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Sample records for confined submarine fans

  1. Miocene Current-Modified Submarine Fans

    NASA Astrophysics Data System (ADS)

    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.

  2. Submarine fans in a sequence stratigraphic framework

    SciTech Connect

    Posamentier, H.W.; Erskine, R.D.; Mitchum, R.M.; Vail, P.R.

    1987-05-01

    Submarine fans are fan- or cone-shaped turbiditic deposits formed in upper bathyal or deeper water depths. Within a sequence stratigraphic framework, these basin-floor turbidites can occur during lowstand-fan or lowstand-wedge systems tract time. During lowstand fan time, streams are rejuvenated and depocenters shift from the coastal plain to the upper slope, causing retrogradational slope failure and canyon formation. The sediment delivered here bypasses the canyon and continues down the slope as a succession of gravity flows and is deposited as fan-shaped turbiditic deposits at the base of the slope. Seismic and outcrop evidence suggest that these sand-prone deposits are abruptly introduced into the basin and are generally characterized by subtle external mounding and internal bidirectionally down lapping seismic reflections where seismically resolvable. Deep-water sediment deposited during this interval has no coeval shelf equivalent. During lowstand wedge time, streams cease down cutting and valleys which have been freshly incised begin to fill. Because coarse sediment will preferentially be deposited within these incised valleys, the sand-to-mud ratio delivered to the upper slope will be decreased and, consequently, there is an inherent difference between submarine fans deposited at this time and those deposited during lowstand fan time. Deposition during lowstand wedge time is characterized seismically by slope front fill or wedge-shaped geometries down lapping the earlier submarine fan (i.e., deposited during lowstand fan time). These shale-prone deposits are largely comprised of thinner-bedded turbidites as well as the occasional leveed channel.

  3. Comparison of depositional elements of an ancient and a modern submarine fan complex: Early Pennsylvanian Jackfork and late Pleistocene Mississippi fans

    SciTech Connect

    Coleman, J.L. Jr. )

    1990-05-01

    Normark urged that all future, meaningful deep-sea fan comparisons be confined to key depositional elements common to most turbidite systems. These elements should include basin size, tectonic and eustatic setting, and depositional process indicators. A test case for elemental comparisons between two widely studied fan complexes is presented and evaluated. The lower Pennsylvanian (Morrowan) Jackfork submarine fan complex extends from central Arkansas to northeast Texas. Sequence analysis suggests that the Jackfork is composed of four to seven depositional episodes and occupies the floor of a deep basin bordered to the north and east by a passive carbonate-siliciclastic shelf margin and to the south and east by a northward-advancing orogenic belt. The Jackfork apparently unrestricted to the west and southwest. The Mississippi submarine fan complex extends from the submerged continental shelf of southern Louisiana to the abyssal depths between Yucatan and Florida. The fan complex is primarily Pleistocene in age, with the present morphologic fan being late Wisconsinian. The Mississippi Fan is composed of 17 depositional episodes. It occupies the floor of a deep basin bordered on the north and west by quiescent( ) halokinetic-siliciclastic shelf margins and to the east and south by passive carbonate margins. Elemental comparisons between the Mississippi fan and a palynspastically restored Jackfork fan complex suggest that both are quite similar, even though the Mississippi fan is up to three times larger in some categories. Comparative study of key depositional elements facilities a more complete understanding of both modern and ancient submarine fans.

  4. Nicolas and Eel submarine fans, California continental borderland

    SciTech Connect

    Reynolds, S.; Gorsline, D.S.

    1987-04-01

    Nicolas and Eel Submarine Fans occur in the San Nicolas basin - an outer basin of the California continental borderland that has a low sedimentation rate. Nicolas Fan lies southeast of San Nicolas Island and the broad San Nicolas Bank. The upper fan is characterized by numerous channels. The midfan region may be divided into three distinct areas: a central midfan and two subfans. The central midfan deposition system is typical of Normark's suprafan. The subfans are essentially flat, sandy lobes. Eel Fan lies west of San Clemente Island and is fed by an erosional valley. Its midfan region may also be characterized as a flat, sandy lobe. Box-core data show that holocene turbidity currents have occurred on the central Nicolas Fan, whereas the subfans and Eel Fan are nearly inactive. The local tectonic regime influences these fans by determining slope trends, creating bathymetric obstacles, controlling canyon location, and triggering mass movements. Sea level changes affect sedimentation patterns of the fans by increasing the mean grain size and the amount of sediment delivered to the fan during lowstands. These changes may, in turn, affect the morphology of the fan. The characteristics of these fans represent variations of the generalized fan models described in the literature. 12 figures, 1 table.

  5. Process sedimentology of submarine fan deposits - new perspectives

    NASA Astrophysics Data System (ADS)

    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

  6. Global classification of spectrum of submarine fan types

    SciTech Connect

    Gorsline, D.S.

    1987-05-01

    There is a pressing need for a schema in which they can arrange the variety of fan forms, both modern and ancient. Such schemes have been generated for the delta depositional form, the beach form, and to some extent for aeolian, fluvial, and glacial deposits. Work by several workers has demonstrated that three necessary dimensions define the variety of submarine fan morphological responses: (1) fan size, (2) sediment supply rate, and (3) the proportion of sand and mud in that supply. These three dimensions form a space within which all submarine fans can be fitted and within which four subspaces can be defined on the basis of order-of-magnitude changes in all three dimensions. Fan morphologies in the less than 10 km scale are simple cones or lobes (suprafan lobes); those of the order of 10 to 100 km may have both lobe and leveed channel components; those in the size range from 100 to 1000 km tend to be dominated by channel systems and are probably composites of smaller fans analogous to crevasse splay systems in very large deltas. Fans larger than about 1000 km are few in number (giant fans) and are dominated by large-scale channels. Megaturbidites are probably limited to systems of the third zone by the constraints of sediment supply and receiving area.

  7. Reservoir properties of submarine- fan facies: Great Valley sequence, California.

    USGS Publications Warehouse

    McLean, H.

    1981-01-01

    Submarine-fan sandstones of the Great Valley sequence west of the Sacramento Valley, California, have low porosities and permeabilities. However, petrography and scanning electron microscope studies indicate that most sands in almost all submarine-fan environments are originally porous and permeable. Thin turbidite sandstones deposited in areas dominated by shale in the outer-fan and basin-plain are cemented mainly by calcite; shale dewatering is inferred to contribute to rapid cementation early in the burial process. Sands deposited in inner- and middle-fan channels with only thin shale beds have small percentrages of intergranular cement. The original porosity is reduced mechanically at shallow depths and by pressure solution at deeperlevels. Permeability decreases with increasing age of the rocks, as a result of increasing burial depths. Computer-run stepwise regression analyses show that the porosity is inversely related to the percentage of calcite cement. The results reported here indicate original porosity and permeability can be high in deep-water submarine fans and that fan environments dominated by sand (with high sand/shale ratios) are more likely to retain higher porosity and permeability to greater depths than sand interbedded with thick shale sequences.-from Author

  8. Modern and ancient submarine fans - reply.

    USGS Publications Warehouse

    Normark, W.T.

    1980-01-01

    A reply to Nilsen's comment (see previous 2 abstracts) on his original paper, which constitutes a critical review of Nilsen's and the author's earlier ideas in the light of new information which has emerged in the interim. Key issues addressed are: 1) clarification of the suprafan concept for modern fans; 2) problems that result from use of morphologic terms in describing ancient systems 3) application of the 'original' Multi-Ricci Lucchi model to modern fans; 4) requirements for more than two models; 5) potential petroleum reservoirs on lower fans; and 6) specific goals for future work.-after Author

  9. Eustatic and structural control of submarine-fan sedimentation, Conception fan, Santa Barbara basin, California

    SciTech Connect

    Thor, D.R.

    1984-04-01

    Eustatic sea level lows provide an opportunity for submarine-fan development; topography and structure, however, can control depositional-sequence geometry. Analysis of high-resolution seismic data provides a basis to evaluate to the evolution and geometry of the Pleistocene-Holocene Conception fan. The fan formed in the restricted, tectonically active Santo Barbara basin. It consists of 4 vertically stacked depositional sequences, each bounded by nondepositional unconformities. The unconformities are defined by seismic-sequence boundaries and were formed during sea-level falls that are related to Pleistocene glacioeustatic changes. Each depositional sequence consists of lowstand, sandrich facies (fan channel, levee, and lobe) topped by highstand, mud-rich facies. The geometry of the depositional sequences tends to be rectilinear, not arcuate, because lateral progradation is restricted by topographically high structures. The modern fan surface and the Holocene depositional sequence provide a good analog for the older, underlying depositional sequences. The fan surface is characterized by 4 main channels, 2 of which head into submarine canyons incised into the shelf. Submarine canyons that fed the other 2 channels are now filled and have no topographic expression. In addition, numerous partially buried channel segments occur in the interchannel areas. The Holocene depositional sequence consists of lenticular and sheet-drape deposits interpreted to be channel, levee, and lobe facies. The facies geometry suggests that Mutti's topographic compensation, channel migration, and avulsion were typical processes on Conception fan.

  10. Newly imaged channel-fan morphology and submarine landslides in the Catalina Basin, southern California Borderland

    NASA Astrophysics Data System (ADS)

    Roland, E. C.; Maier, K. L.; Brothers, D. S.; Kluesner, J.; Conrad, J. E.; Walton, M. A. L.; Balster-Gee, A. F.; Hart, P. E.

    2016-12-01

    Basin and ridge bathymetry in the strike-slip-dominated California Borderland provides a unique setting for exploring submarine channel and fan evolution influenced by Quaternary faulting and sea-level variations. Until recently, minimal data had been collected in the inner Borderland Catalina Basin, despite its location just 70 km offshore Los Angeles in proximity to the San Clemente and Catalina faults. A joint USGS and University of Washington survey in February 2016 collected new high-resolution multichannel seismic-reflection data, chirp sub-bottom profiles, and multibeam bathymetry in the Catalina Basin from 1000 to 1500 m water depth. Combined with previous surveys, these new data provide the first continuous multibeam bathymetric coverage of the distally sourced San Gabriel canyon-channel-fan system and high-resolution subsurface imaging in the Catalina Basin. The transition from channel to fan morphology is imaged particularly clearly in the eastern, proximal portion of Catalina Basin to 1250 m water depth. The San Gabriel Channel appears tectonically confined by uplifted fault blocks at its entry into the basin, where channel confinement rapidly decreases. Several other discontinuous channels, knickpoints, and scours are imaged to the west, where changes in confinement appear to be associated with uplifted ridges. Seismic-reflection profiles suggest that the location of fan depocenters has shifted during basin evolution, possibly linked to transpressional motion along the Catalina and San Clemente faults. The Catalina Basin may receive additional locally sourced sediment input from relatively smaller canyons, gullies, and submarine landslides along the flanks of the Catalina and San Clemente Islands. For example, a submarine landslide headscarp and associated deposit (area 2 km2) are imaged along the fault-controlled flank of the Catalina platform, suggesting a potential linkage between active faulting and slope failure.

  11. Internal geometry, seismic facies, and petroleum potential of canyons and inner fan channels of the Indus submarine fan

    SciTech Connect

    McHargue, T.R.; Webb, J.E.

    1986-02-01

    The Indus Fan, the second largest submarine fan in the world, covers 1,250,000 km/sup 2/ (500,000 mi/sup 2/) and contains sediment more than 7 km (23,000 ft) thick. Multichannel (24-fold) CDP seismic data provide the bases for evaluating the Indus Fan and consist of four seismic facies. Of these, only the high-amplitude, discontinuous (H-D) facies is thought to contain reservoir-quality sandstones. The H-D facies is confined to the axes of leveed channels. Canyon-channel systems that fed the fan in the past can be divided into three zones. The degradational zone is composed of an erosional canyon complex filled by prodelta mud. The transitional zone, located near the canyon mouth, consists of superimposed channels that initially were erosional but eventually aggraded and developed levees. The headward termination of the H-D facies occurs in this zone. The aggradational zone consists of superimposed leveed channels confined solely by their own levees. The proximal termination of the H-D facies near canyon mouths implies the presence of reservoir-quality sandstone surrounded by source/seal mudstone in the transitional zone. This stratigraphic trapping geometry and structural leads may represent a vast, untapped petroleum province.

  12. Tufts submarine fan: turbidity-current gateway to Escanaba Trough

    USGS Publications Warehouse

    Reid, Jane A.; Normark, William R.

    2003-01-01

    Turbidity-current overflow from Cascadia Channel near its western exit from the Blanco Fracture Zone has formed the Tufts submarine fan, which extends more than 350 km south on the Pacific Plate to the Mendocino Fracture Zone. For this study, available 3.5-kHz high-resolution and airgun seismic-reflection data, long-range side-scan sonar images, and sediment core data are used to define the growth pattern of the fan. Tufts fan deposits have smoothed and filled in the linear ridge-and-valley relief over an area exceeding 23,000 km2 on the west flank of the Gorda Ridge. The southernmost part of the fan is represented by a thick (as much as 500 m) sequence of turbidite deposits ponded along more than 100 km of the northern flank of the Mendocino Fracture Zone. Growth of the Tufts fan now permits turbidity-current overflow from Cascadia Channel to reach the Escanaba Trough, a deep rift valley along the southern axis of the Gorda Ridge. Scientific drilling during both the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) provided evidence that the 500-m-thick sediment fill of Escanaba Trough is dominantly sandy turbidites. Radiocarbon dating of the sediment at ODP Site 1037 showed that deposition of most of the upper 120 m of fill was coincident with Lake Missoula floods and that the provenance of the fill is from the eastern Columbia River drainage basin. The Lake Missoula flood discharge with its entrained sediment continued flowing downslope upon reaching the ocean as hyperpycnally generated turbidity currents. These huge turbidity currents followed the Cascadia Channel to reach the Pacific Plate, where overbank flow provided a significant volume of sediment on Tufts fan and in Escanaba Trough. Tufts fan and Tufts Abyssal Plain to the west probably received turbidite sediment from the Cascadia margin during much of the Pleistocene.

  13. Submarine canyon and fan systems of the California Continental Borderland

    USGS Publications Warehouse

    Normark, W.R.; Piper, D.J.W.; Romans, B.W.; Covault, J.A.; Dartnell, P.; Sliter, R.W.

    2009-01-01

    Late Quaternary turbidite and related gravity-flow deposits have accumulated in basins of the California Borderland under a variety of conditions of sediment supply and sea-level stand. The northern basins (Santa Barbara, Santa Monica, and San Pedro) are closed and thus trap virtually all sediment supplied through submarine canyons and smaller gulley systems along the basin margins. The southern basins (Gulf of Santa Catalina and San Diego Trough) are open, and, under some conditions, turbidity currents flow from one basin to another. Seismic-reflection profiles at a variety of resolutions are used to determine the distribution of late Quaternary turbidites. Patterns of turbidite-dominated deposition during lowstand conditions of oxygen isotope stages 2 and 6 are similar within each of the basins. Chronology is provided by radiocarbon dating of sediment from two Ocean Drilling Program sites, the Mohole test-drill site, and large numbers of piston cores. High-resolution, seismic-stratigraphic frameworks developed for Santa Monica Basin and the open southern basins show rapid lateral shifts in sediment accumulation on scales that range from individual lobe elements to entire fan complexes. More than half of the submarine fans in the Borderland remain active at any given position of relative sea level. Where the continental shelf is narrow, canyons are able to cut headward during sea-level transgression and maintain sediment supply to the basins from rivers and longshore currents during highstands. Rivers with high bedload discharge transfer sediment to submarine fans during both highstand and lowstand conditions. ?? 2009 The Geological Society of America.

  14. Tectonically controlled fan delta and submarine fan sedimentation of late Miocene age, southern Temblor Range, California

    USGS Publications Warehouse

    Ryder, Robert T; Thomson, Alan

    1989-01-01

    The Santa Margarita Formation in the southern Temblor Range, composed of conglomerate and subordinate sandstone, evolved as a large complex of fan deltas and submarine fans in late Miocene time. An 80 to 90-m.y.-old granitic basement of the Salinian block and an accompanying 23.5-m.y.-old volcanic field now located in the northern Gabilan Range and the Pinnacles area, respectively, were the primary source terranes. In general, the fan deltas crop out along the west side of the southern Temblor Range, whereas the proximal parts of the submarine fans crop out along the east side of the range. The fan deltas consist of subaerial topset beds and low-angle basinward-dipping subaqueous foreset beds. Strata interpreted to be topset beds are composed largely of conglomerate with thick to very thick horizontal beds and matrix-supported clasts. Most of the thick to very thick conglomerate beds are internally massive and disorganized. Strata interpreted as foreset beds are composed of thick-bedded, large-scale, low-angle, cross-stratified conglomerate and sandstone units which commonly are internally massive. Abundant molluskan macrofossils such as Ostrea and Pecten are present in the subaqueous foreset beds; many have been displaced downslope from their original site of deposition. Conglomerate- and sandstone-filled submarine canyons, through which coarse-grained detritus was transported to the adjacent submarine fans, locally have cut into the foreset beds of the fan deltas. These submarine canyon deposits are generally better stratified than adjacent foreset-bed deposits, and they consist of thick horizontal beds, internally massive or normally graded, arranged in fining- and thinning-upward sequences. Isolated and composite conglomerate- and sandstone-filled channels, which crop out on the east flank of the southern Temblor Range, are interpreted as proximal submarine-fan channel deposits. These channel-form conglomerate and sandstone deposits are characterized by thick

  15. Tectonically controlled fan delta and submarine fan sedimentation of late Miocene age, southern Temblor Range, California

    USGS Publications Warehouse

    Ryder, Robert T; Thomson, Alan

    1989-01-01

    The Santa Margarita Formation in the southern Temblor Range, composed of conglomerate and subordinate sandstone, evolved as a large complex of fan deltas and submarine fans in late Miocene time. An 80 to 90-m.y.-old granitic basement of the Salinian block and an accompanying 23.5-m.y.-old volcanic field now located in the northern Gabilan Range and the Pinnacles area, respectively, were the primary source terranes. In general, the fan deltas crop out along the west side of the southern Temblor Range, whereas the proximal parts of the submarine fans crop out along the east side of the range. The fan deltas consist of subaerial topset beds and low-angle basinward-dipping subaqueous foreset beds. Strata interpreted to be topset beds are composed largely of conglomerate with thick to very thick horizontal beds and matrix-supported clasts. Most of the thick to very thick conglomerate beds are internally massive and disorganized. Strata interpreted as foreset beds are composed of thick-bedded, large-scale, low-angle, cross-stratified conglomerate and sandstone units which commonly are internally massive. Abundant molluskan macrofossils such as Ostrea and Pecten are present in the subaqueous foreset beds; many have been displaced downslope from their original site of deposition. Conglomerate- and sandstone-filled submarine canyons, through which coarse-grained detritus was transported to the adjacent submarine fans, locally have cut into the foreset beds of the fan deltas. These submarine canyon deposits are generally better stratified than adjacent foreset-bed deposits, and they consist of thick horizontal beds, internally massive or normally graded, arranged in fining- and thinning-upward sequences. Isolated and composite conglomerate- and sandstone-filled channels, which crop out on the east flank of the southern Temblor Range, are interpreted as proximal submarine-fan channel deposits. These channel-form conglomerate and sandstone deposits are characterized by thick

  16. The importance of shallow confining units to submarine groundwater flow

    USGS Publications Warehouse

    Bratton, J.F.

    2007-01-01

    In addition to variable density flow, the lateral and vertical heterogeneity of submarine sediments creates important controls on coastal aquifer systems. Submarine confining units produce semi-confined offshore aquifers that are recharged on shore. These low-permeability deposits are usually either late Pleistocene to Holocene in age, or date to the period of the last interglacial highstand. Extensive confining units consisting of peat form in tropical mangrove swamps, and in salt marshes and freshwater marshes and swamps at mid-latitudes. At higher latitudes, fine-grained glaciomarine sediments are widespread. The net effect of these shallow confining units is that groundwater from land often flows farther offshore before discharging than would normally be expected. In many settings, the presence of such confining units is critical to determining how and where pollutants from land will be discharged into coastal waters. Alternatively, these confining units may also protect fresh groundwater supplies from saltwater intrusion into coastal wells.

  17. Seismic expression of Late Quaternary Banda submarine canyon and fan offshore northern Baja California

    SciTech Connect

    Legg, M.R.

    1987-05-01

    High-resolution seismic reflection profiles obtained throughout the inner California continental borderland offshore northwestern Baja California, Mexico, show the presence of numerous modern submarine canyons and associated fans. One set of these, the Banda submarine canyon/fan, is of relatively recent origin, as demonstrated by onlap of the basal fan sediments against an acoustically transparent, presumably hemipelagic deposit. Late Quaternary sedimentation rates inferred from isotopically dated piston core samples place the age of the postulated hemipelagic unit at approximately 650,000 years ago. The Banda submarine canyon heads within the Bahia Todos Santo and passes through a narrow gorge between Punta Banda and Islas Todos Santos. It is proposed that this submarine canyon and fan system formed entirely during late Quaternary time, following the breach of the Punta Banda ridge during a late Pleistocene high sea level stand. The presence of an ancient, buried channel exiting to the north out of Bahia Todos Santos probably marks the head of an earlier submarine canyon which acted as the conduit of clastic sediments from Valle Maneadero to the deep borderland basins. The now active Banda submarine canyon pirated the supply of terrigenous clastics from this older canyon. The active Agua Blanca fault zone cuts across the head of Banda submarine canyon, suggesting that tectonic movements may have played a role in the development of the Banda submarine canyon and fan system.

  18. Channel fill characteristics in submarine fans and deltas

    SciTech Connect

    Bouma, A.H.; Goddard, D. )

    1993-02-01

    Excellent data sources may not answer all pertinent questions and multifold seismic data usually cannot resolve internal characteristics of channel fills, even when it can detect the channel. Well log correlations can be wrong, especially when dealing with thin channel fills and outcrops are seldom sufficiently large to reveal a complete channel fill. In the final analysis, integration of all these types of data is necessary. Although not well understood, a lot of similarities exist between the channel fills from submarine fans and those from deltas. It is definitely beneficial to compare data from both environments. Channels and their fills can be: (1) primarily the result of major erosion forming an incisement that becomes gradually filled; (2) primarily the result of deposition, maintaining a channel, gradually filling it and simultaneously building its levees; (3) massive fill; (4) a bedded fill with or without an upward and/or lateral thinning or fining; or (5) a combination of thick bedded and thin bedded. Many channels alternate between erosional and depositional activities. Often an erosional cut is lined with shale, reducing fluid flow between channel sandstones and those of the levees. Also, a thorough knowledge of all of these varied processes is essential for the understanding of why [open quotes]massive[close quotes] channel fills can be wet and [open quotes]thin-bedded levees[close quotes] deposits oil prone.

  19. Modern and ancient submarine fans: discussion of papers by Walker and Normark.

    USGS Publications Warehouse

    Nilsen, T.H.

    1980-01-01

    A comment on two papers, by Walker (GeoAbstracts 78E/2328) and Normark (GeoAbstracts 78E/2278), in which attempts were made to synthesize current concepts and models of deep-marine sedimentation for modern and ancient submarine fans. Argues that several important aspects of these papers are misleading - namely, Walker's confusing use of the term 'thick-bedded' for 'proximal', problems introduced by application of the suprafan concept to ancient fan deposits; and unfortunate overemphasis of channeled submarine fan deposits as exploration targets.-after Author

  20. Sedimentary, tectonic, and sea-level controls on submarine fan and slope-apron turbidite systems

    USGS Publications Warehouse

    Stow, D.A.V.; Howell, D.G.; Nelson, C.H.

    1984-01-01

    To help understand factors that influence submarine fan deposition, we outline some of the principal sedimentary, tectonic, and sea-level controls involved in deep-water sedimentation, give some data on the rates at which they operate, and evaluate their probable effects. Three depositional end-member systems, two submarine fan types (elongate and radial), and a third nonfan, slope-apron system result primarily from variations in sediment type and supply. Tectonic setting and local and global sea-level changes further modify the nature of fan growth, the distribution of facies, and the resulting vertical stratigraphic sequences. ?? 1984 Springer-Verlag New York Inc.

  1. Outcrop-scale acoustic facies analysis and latest Quaternary development of Hueneme and Dume submarine fans, offshore California

    USGS Publications Warehouse

    Piper, D.J.W.; Hiscott, R.N.; Normark, W.R.

    1999-01-01

    The uppermost Quaternary deposits of the Hueneme and Dume submarine fans in the Santa Monica Basin have been investigated using a closed-spaced grid of boomer seismic-reflection profiles, which give vertical resolution of a few tens of centimetres with acoustic penetration to 50 m. Acoustic facies integrated with geometry define six architectural elements, some with discrete subelements that are of a scale that can be recognized in outcrops of ancient turbidite systems. In the Santa Monica Basin, the relationship of these elements to fan morphology, stratigraphy and sediment source is precisely known. The width of upper Hueneme fan valley has been reduced from 5 km since the last glacial maximum to 1 km at present by construction of laterally confined sandy levees within the main valley. The middle fan comprises three main subelements: thick sand deposits at the termination of the fan valley, low-gradient sandy lobes typically 5 km long and < 10 m thick, and scoured lobes formed of alternating sand and mud beds with many erosional depressions. The site of thickest lobe sediment accumulation shifts through time, with each sand bed deposited in a previous bathymetric low (i.e. compensation cycles). The lower fan and basin plain consists of sheet-like alternations of sand and mud with shallow channels and lenses. Variations in the rate of late Quaternary sea level rise initiated changes in sediment facies distribution. At lowstand, and during the approximately 11 ka stillstand in sea level, the Hueneme Fan was fed largely by hyperpycnal flow from the Santa Clara River delta, depositing high sediment waves on the right hand levee and thick sandy lobes on the middle fan. At highstand of sea level, most turbidity currents were generated by failure of silty prodelta muds. In contrast, the smaller Dume Fan was apparently always fed from littoral drift of sand through a single-canyon point source.

  2. A passive margin-type submarine fan complex, Permian Ecca Group, South Africa

    SciTech Connect

    Wickens, H.D. ); Bouma, A.H. )

    1991-03-01

    A submarine fan complex, comprising five arenaceous fan systems separated by basinal shale units, occurs in the southwestern part of the intracratonic Karoo basin in South Africa. Although basin development is related to a subduction zone bordering the palaeo-Pacific ocean to the south of Gondwanaland and the evolution of the Cape Fold Belt, the entire Lower Permian Ecca Group basin-fill succession reflects depositional characteristics of a passive-margin setting. The submarine fan complex, 250 m thick, originated from sediments supplied by Mississippi-type deltas dominating the Ecca coastline. The fine grain-size and low sand/shale ratio of the submarine fan and deltaic deposits reflect the maturity of the ancient river systems. Outcrops of the fan complex are well exposed and cover an area of 650 km{sup 2}. The strata are not affected by folding, and deep erosion allows three-dimensional viewing of mid-fan to outer-fan deposits. Features of interest include stacked lobe deposits displayed along 2.5 km of a 60 m high cliff section, and a transverse cliff section through channel-fill deposits 500 m wide. Paleocurrent directions reveal that each sequence had its own main source area located to the northwest and south of its present geographic location. The cyclic nature of the fan complex is attributed to relative sea-level changes; deposition took place on the basin floor in water depths that do not exceed 500 m. Shoaling of the basin to wave base depths is reflected in the pro-delta and delta front deposits overlying the uppermost fan sequence. Major factors in controlling direction of fan progradation were delta switching and basin floor topography.

  3. Drainage systems associated with mid-ocean channels and submarine Yazoos: Alternative to submarine fan depositional systems

    SciTech Connect

    Hesse, R. )

    1989-12-01

    Submarine drainage systems associated with mid-ocean channels and Yazoo River-type tributaries in small ocean basins represent a contrast to deep-sea fan depositional systems. Deep-sea fans are diverging sediment-dispersal systems of distributary fan valleys. Deep-sea channel-submarine-yazoo systems, on the other hand, form centripetally converging patterns of tributaries and yazoo-type satellite channels that join a major basin-draining (mid-ocean) channel. The facies model for such systems is characterized by randomly stacked fining-upward, gravelly, and sandy channel-fill and submarine point-bar sequences of the main channel encased in fine-grained overbank deposits. Second-order channels contain sandy proximal overbank deposits, whereas the levees of the main channel are predominantly composed of silt and clay. Second-order channels may be braided and may broaden into braid plains. Morphology and surficial sediment distribution have been studied within the Northwest Atlantic Mid-Ocean Channel of the Labrador Sea and its associated levees and yazoo-type (and other) tributaries.

  4. Sea level controls on the textural characteristics and depositional architecture of the Hueneme and associated submarine fan systems, Santa Monica Basin, California

    USGS Publications Warehouse

    Normark, W.R.; Piper, D.J.W.; Hiscott, R.N.

    1998-01-01

    Hueneme and Dume submarine fans in Santa Monica Basin consist of sandy channel and muddy levee facies on the upper fan. lenticular sand sheets on the middle fan. and thinly bedded turbidite and hemipelagic facies elsewhere. Fifteen widely correlatable key seismic reflections in high-resolution airgun and deep-towed boomer profiles subdivide the fan and basin deposits into time-slices that show different thickness and seismic-facies distributions, inferred to result from changes in Quaternary sea level and sediment supply. At times of low sea level, highly efficient turbidity currents generated by hyperpycnal flows or sediment failures at river deltas carry sand well out onto the middle-fan area. Thick, muddy flows formed rapidly prograding high levees mainly on the western (right-hand) side of three valleys that fed Hueneme fan at different times: the most recently active of the lowstand fan valleys. Hueneme fan valley, now heads in Hueneme Canyon. At times of high sea level, fans receive sand from submarine canyons that intercept littoral-drift cells and mixed sediment from earthquake-triggered slumps. Turbidity currents are confined to 'underfit' talweg channels in fan valleys and to steep, small, basin-margin fans like Dume fan. Mud is effectively separated from sand at high sea level and moves basinward across the shelf in plumes and in storm-generated lutite flows, contributing to a basin-floor blanket that is locally thicker than contemporary fan deposits and that onlaps older fans at the basin margin. The infilling of Santa Monica Basin has involved both fan and basin-floor aggradation accompanied by landward and basinward facies shifts. Progradation was restricted to the downslope growth of high muddy levees and the periodic basinward advance of the toe of the steeper and sandier Dume fan. Although the region is tectonically active, major sedimentation changes can be related to eustatic sea-level changes. The primary controls on facies shifts and fan growth

  5. Characteristics of some submarine fan channels, Permian Ecca Group, South Africa

    SciTech Connect

    Bouma, A.H. ); Dev Wickens, H. )

    1991-03-01

    The vary well exposed submarine fan complex in the southwestern part of the Karoo basin permits close examination of channel-fills and in places their associated overbank deposits. The complex comprises five arenaceous fan systems some of which attain 60 m in thickness. The fans are vertically stacked and separated by basinal shale deposits; each system with its own direction of growth. The association of channelized sandstone bodies and thin-bedded sandstone and shale packages in an updip position from predominantly stacked lobe deposits suggest preservation of middle fan settings. A 500 m wide, 20 m thick channel-fill consisting massive amalgamated sandstone beds occupying the channel thalweg occurs in a setting dominated by thin-bedded, ripple-laminated sandstone and shale. Gradual thinning of the channel-fill beds toward the channel edges, lack of internal lateral accretion, and a high width to depth ratio suggests a low sinuous to straight channel. The channel-fill is capped by an abandonment facies characterized by ripple-laminated sandstone and shale. Stacked, laterally offset channel-fill deposits with highly erosional contacts and typical well-bedded overbank deposits form channel-overbank complexes and characterize the mid-fan region of the uppermost fan system. Palaeocurrent directions and gradual diminishing of bed-thickness away from the generally massively bedded, amalgamated channel-fill sandstones confirm a simultaneous channel/overbank origin for these deposits. Levee morphology has not been recognized. Both examples of channel-fills cited reveal part of the complexity of the channelized portions of submarine fans and hence the implications thereof in exploring for hydrocarbon reservoirs.

  6. Autogenic processes and deposit signatures in laboratory submarine fan experiments with supercritical alluvial channels

    NASA Astrophysics Data System (ADS)

    Strom, Kyle; Hamilton, Paul; Hoyal, David; Fedele, Juan

    2017-04-01

    Submarine fans are an amalgamation of channels and lobes built over time on the continental slope and abyssal plain through multiple avulsion cycles. This research experimentally explores supercritical submarine fan building processes from a hydraulic and sediment transport perspective. Data for this was provided by a new methodology developed to measure the layer-averaged hydraulic variables of small-scale density currents that change with space and time as they construct the fan. In the presentation, we will present the autogenic avulsion cycle observed, discuss why steep systems can potentially produce "perched" lobes, show the characteristics of lobe and channel fill deposits resulting from a single avulsion cycle, and present data describing the overall development of the fan through multiple avulsion cycles. The experiments showed that the primary avulsion cycle consisted of the following phases: channel incision and basinward extension, cessation of channel extension and mouth bar formation, bar aggradation and hydraulic jump initiation, and upstream propagation of the channel-to-lobe transition. The transition from erosion or bypass in the channels to deposition in an expanded-flow region downstream led to a choked-flow condition that caused a hydraulic jump to initiate before reaching the basin floor. Each avulsion cycle was responsible for an associated lobe deposit. Since hydraulic jumps were common during avulsion cycles, they were used to predict the maximum thickness of the lobe deposits as a function of the upstream flow depth and Froude number. The lobes emplaced by discrete avulsion cycles stacked up over time to form the overall fan. Though each cycle contained elements of both basinward extension and upstream backfilling, the fans showed net progradation at a long-term rate that can be representatively modeled using a mass balance approach based on sediment supply and equilibrium fan slope.

  7. Evolution of Paleogene submarine Canyon-Fan systems, southern Sacramento basin, California

    SciTech Connect

    Fischer, P.J.; Cherven, V.B.; Almgren, A.A.

    1986-04-01

    The evolutionary development of the Paleogene Martinez and Meganos Submarine Canyon and Fan systems of the southern Sacramento basin was controlled by a complex interplay of eustatic sea level change and tectonism. In this brief synthesis, the authors postulated that eustatic sea level changes were the dominant or controlling factor, and tectonism, although significant, was of secondary importance. The development of the Paleogene canyon and fan systems is correlated with low sea level stands or regressions at 60 Ma and 56 Ma. Intermittent tectonism, beginning at least 5-10 m.y. earlier, particularly along the western and southwestern margins of the Sacramento basin, controlled the location of the canyon and fan systems. The controlling tectonic elements of the southern basin were north-trending, high-angle faults related to the Kirby Hills and Midland fault zones and the Diablo-Kirby Hills(.) uplift. Both canyons were probably active (that is, channeling coarse sediment to their fans) during most of the late Paleocene. The authors suggest that canyon activity was maintained by south-flowing longshore drift or feeder systems, down-canyon gravity flows (turbidites, etc) and up-down canyon current systems, all of which are typical of modern, active submarine canyon and fan systems. The canyons filled with fine-grained sediments when the canyons were beheaded or separated from the longshore drift system by rising sea level, or when tectonism(.) shifted the major river drainage that supplied the canyon with sediment. Truncation and erosion of the canyon-fill and fan facies of the late Paleocene-early Eocene Meganos Formation along the Diablo outcrop belt was primarily due to the major early middle Eocene lowstand (49.5 Ma).

  8. Carbonate apron models: Alternatives to the submarine fan model for paleoenvironmental analysis and hydrocarbon exploration

    USGS Publications Warehouse

    Mullins, H.T.; Cook, H.E.

    1986-01-01

    Sediment gravity flow deposition along the deep-water flanks of carbonate platforms typically does not produce submarine fans. Rather, wedge-shaped carbonate aprons develop parallel to the adjacent shelf/slope break. The major difference between submarine fans and carbonate aprons is a point source with channelized sedimentation on fans, versus a line source with sheet-flow sedimentation on aprons. Two types of carbonate aprons may develop. Along relatively gentle (< 4??) platform-margin slopes, aprons form immediately adjacent to the shallow-water platform and are referred to as carbonate slope aprons. Along relatively steep (4-15??) platform margin slopes, redeposited limestones accumulate in a base-of-slope setting, by-passing an upper slope via a multitude of small submarine canyons, and are referred to as carbonate base-of-slope aprons. Both apron types are further subdivided into inner and outer facies belts. Inner apron sediments consist of thick, mud-supported conglomerates and megabreccias (Facies F) as well as thick, coarse-grained turbidites (Facies A) interbedded with subordinate amounts of fine-grained, peri-platform ooze (Facies G). Outer apron sediments consist of thinner, grain-supported conglomerates and turbidites (Facies A) as well as classical turbidites (Facies C) with recognizable Bouma divisions, interbedded with approximately equal proportions of peri-platform ooze (Facies G). Seaward, aprons grade laterally into basinal facies of thin, base-cut-out carbonate turbidites (Facies D) that are subordinate to peri-platform oozes (Facies G). Carbonate base-of-slope aprons grade shelfward into an upper slope facies of fine-grained peri-platform ooze (Facies G) cut by numerous small canyons that are filled with coarse debris, as well as intraformational truncation surfaces which result from submarine sliding. In contrast, slope aprons grade shelfward immediately into shoal-water, platform-margin facies without an intervening by-pass slope. The two

  9. Mid-Cretaceous submarine fans of the southwest Bredasdorp basin, South Africa

    SciTech Connect

    Gilbert, C. )

    1991-03-01

    Mid-Cretaceous lowstand systems tracts, containing varying thicknesses of sandstone, have been identified in the E-G subbasin, south-central Bredasdorp basin, offshore South Africa. These lowstand tracts overlie a type 1 unconformity of Albian age, related to erosion of submarine channels into the lower continental slope. Five boreholes drilled in this area to date were located either at the break of continental slope on this unconformity or slightly distal thereto. Four wells were designed primarily to test Late Jurassic-Early Cretaceous rift-fill sequences beneath the drift onset (Gondwanaland breakup) unconformity. The fifth borehole tested mid-Cretaceous lowstand sandstones, following reappraisal of their reservoir quality and hydrocarbon shows, based on the earlier boreholes. Gamma-ray log motifs together with seismic interpretations, petrographic evidence from cores, and sidewall cores and cuttings permit the interpretation of various subenvironments, from proximal feeder channel to distal supra-fan lobe settings of a deep-marine fan or fans. It is proposed that these fans represent the first phase of sedimentation on the Albian type 1 unconformity surface during conditions of falling sea level. Sediment, possibly eroded from highstand fan deltas or shelf sands on a partially exposed shelf to the south, was transported down erosional submarine channels. A proximal source and high gradients favored the high sand:mud ratio encountered in these wells. Local tectonic activity of short duration along faults parallel to the Agulhas fracture zone may have contributed to gradient steepening. Latest drilling results have upgraded similar plays distal to erosional channels in the immediate area.

  10. The development of a laterally confined laboratory fan delta under sediment supply reduction

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaofeng; Wang, Siqiang; Wu, Xi; Xu, Shun; Li, Zhangyong

    2016-03-01

    In previous fan delta experiments, the effect of lateral confinement was generally ignored as these fans were usually unconfined with semiconical geometries. However, in gorge areas, fan development is usually laterally confined by valley walls. This study investigates autogenic processes of fan deltas in a laterally confined experimental tank. The experiment is divided into three phases. The sediment supply is held constant within each phase, so the autogenic processes of the fan are separated from the allogenic forcings. Results indicate that laterally confined fan deltas have higher progradation and aggradation potential, more regular channel braiding, and more even transverse sedimentation than unconfined fans. Besides, responses of fan deltas to sediment supply reduction are investigated in this research. At the initiation of the second and third phases, sediment feed rates are instantaneously reduced so that the allogenic forcings are predominant. Observations show that under sediment supply reduction, channelization on fan deltas are more pronounced and durations of the fluvial cycles are longer. The adjustment of fan morphology becomes slower as the self-regulation capacity of the fan decreases with reduced sediment supply.

  11. Paleogene Submarine Fan Depocenters of the Abyssal Gulf of Mexico: Paleogeography, Provenance, and Tectonic Implications

    NASA Astrophysics Data System (ADS)

    Winker, C. D.

    2008-05-01

    In the abyssal Gulf of Mexico (AGOM) seven major Paleogene submarine fan depocenters are identified on regional 2D and local 3D seismic data tied to wells on adjacent structural belts. Source directions are inferred from (1) location of isopach maxima relative to paleo-margins; (2) seismic facies; (3) channel orientations on 3D seismic; and (4) sandstone composition, particularly that of lithic grains. Paleogene fan depocenters in the southwestern and southeastern AGOM are associated with relatively narrow and high-gradient (several degrees), high-bypass continental margins adjacent to orogenic belts. The (1) Chicontepec Fan (Paleocene, syn-Laramide) and (2) Post-Chicontepec Fan (Eocene-Oligocene) had westerly sources in east-central Mexico. Sandstone lithic modes are predominantly carbonate in the Chicontepec and mixed volcanic-carbonate in the Post-Chicontepec. The Laramide-age (3) Straits of Florida depocenter (Paleocene-Eocene?) was sourced from Cuba to the southeast; sandstone composition is unknown. In contrast, Paleogene fan depocenters in the northwestern AGOM are associated with large deltaic depocenters, low- to moderate-bypass margins, and very low-gradient (1 degree or less) continental slopes. The Wilcox fans (Upper Paleocene-Lower Eocene, syn-Laramide) had a dominant source direction to the northwest, but can be separated into (4) Lower Wilcox (northerly source), (5) Middle Wilcox (westerly source in NE Mexico), and (6) Upper Wilcox (westerly to northwesterly source). Like the Upper Wilcox, the (7) Frio fan depocenter (Middle Oligocene) had a westerly source associated with a large deltaic depocenter. Sandstone lithic modes of Wilcox fans range from metamorphic to mixed metamorphic-volcanic, clays are predominantly illite, and polygonal faulting is absent. Sandstones of the overlying Post-Chicontepec and Frio fans are mixed volcanic-carbonate, clays are smectite-rich, and polygonal faulting is abundant. Six of these depocenters attain maximum

  12. Hydraulic and sediment transport properties of autogenic avulsion cycles on submarine fans with supercritical distributaries

    NASA Astrophysics Data System (ADS)

    Hamilton, Paul B.; Strom, Kyle B.; Hoyal, David C. J. D.

    2015-07-01

    Submarine fans, like other distributive systems, are built by repeated avulsion cycles. However, relative to deltas and alluvial fans, much less is known about avulsions in subaqueous settings. In this study, we ran a set of subaqueous fan experiments to investigate the mechanics associated with autogenic avulsion cycles of self-formed channels and lobe deposits on steep slopes. The experiments used saline density currents with crushed plastic to emulate sustained turbidity currents and bed load transport. We collected detailed hydraulic and bathymetric measurements and made use of a 1-D laterally expanding density current model to better understand different aspects of the avulsion cycle. Our results reveal three major components of the avulsion cycles: (1) distributary channel incision, extension, and stagnation; (2) mouth bar aggradation and hydraulic jump initiation; and (3) hydraulic jump sedimentation and upstream retreat. Interestingly, in all but one experiment, the avulsion cycles led to fans that remained perched above the basin slope break. Experimental data and hydraulic theory were used to unravel actual mechanics associated with cycles. We found that channels stopped extending into the basin due to a decay in sediment transport capacity relative to sediment supply and that the reduction in capacity was primarily an outcome of expansion-driven velocity reduction; dilution played a secondary role. Once channel extension ceased, mouth bar deposits aggraded to a thickness approximately equal to the critical step height needed to create a choked flow condition. The choke then initiated a hydraulic jump on the upstream side of the bar. Once formed, the jump detained a majority of the incoming sediment and forced the channel-to-lobe transition upstream, filling the channel with steep backset bedding and capping the entire channel with a mounded lobate deposit. These intrinsic processes repeated through multiple avulsion cycles to build the fan.

  13. Anatomy of a submarine fan complex, Exmouth sub-basin, western Australia

    SciTech Connect

    Arditto, P.A.

    1996-12-31

    A process sedimentologic and sequence stratigraphic study of the basal Berriasian-aged Barrow Group was undertaken within the Macedon Gas Field, WA-155-P, Exmouth Sub-basin, using conventional core and wireline log data. Due to poor data quality the 3D seismic could not be integrated into the study. The study concentrated on basal sandstone reservoirs now interpreted to be a submarine debris flow and grain flow fan complex. These sands developed as a result of rapid sediment loading of the prograding Barrow Group shelf margin with subsequent collapse of the margin and sediment transport to an offshore setting. Detailed core process sedimentology tied into wireline log motifs indicates that sediment transport was by grain flow and minor debris flow; true turbidities are rare. The inferred sediment source were shelf margin barrier bar and stream mouth bar units located to the southeast. This postulated source area has been subsequently uplifted and removed through erosion by regional intra-Valanginian tectonism. A well correlation diagram was constructed to help delineate the distribution of five fan cycles. A regionally significant third-order maximum flooding surface, slightly younger than the fan complex, was used as a stratigraphic datum for the correlation. Isopach and percent sand maps for each of the fans display a general east to southeast progressive displacement in both depocentre and maximum sand content. This is interpreted to be a response to a more general transgressive event within the basal portion of the Barrow Group, culminating in the third-order maximum flooding surface used as the stratigraphic datum. The entire fan complex appears to have limited areal extent which may limit both the capture area for gas charging and the water drive capacity for gas production.

  14. Anatomy of a submarine fan complex, Exmouth sub-basin, western Australia

    SciTech Connect

    Arditto, P.A. )

    1996-01-01

    A process sedimentologic and sequence stratigraphic study of the basal Berriasian-aged Barrow Group was undertaken within the Macedon Gas Field, WA-155-P, Exmouth Sub-basin, using conventional core and wireline log data. Due to poor data quality the 3D seismic could not be integrated into the study. The study concentrated on basal sandstone reservoirs now interpreted to be a submarine debris flow and grain flow fan complex. These sands developed as a result of rapid sediment loading of the prograding Barrow Group shelf margin with subsequent collapse of the margin and sediment transport to an offshore setting. Detailed core process sedimentology tied into wireline log motifs indicates that sediment transport was by grain flow and minor debris flow; true turbidities are rare. The inferred sediment source were shelf margin barrier bar and stream mouth bar units located to the southeast. This postulated source area has been subsequently uplifted and removed through erosion by regional intra-Valanginian tectonism. A well correlation diagram was constructed to help delineate the distribution of five fan cycles. A regionally significant third-order maximum flooding surface, slightly younger than the fan complex, was used as a stratigraphic datum for the correlation. Isopach and percent sand maps for each of the fans display a general east to southeast progressive displacement in both depocentre and maximum sand content. This is interpreted to be a response to a more general transgressive event within the basal portion of the Barrow Group, culminating in the third-order maximum flooding surface used as the stratigraphic datum. The entire fan complex appears to have limited areal extent which may limit both the capture area for gas charging and the water drive capacity for gas production.

  15. A million miles from rivers: secondary flow in submarine canyon-fan systems.

    NASA Astrophysics Data System (ADS)

    Dorrell, Robert; Darby, Steve; Peakall, Jeff; Parsons, Dan; Sumner, Esther; Wynn, Russell

    2013-04-01

    In both subaerial and submarine meander bends, fluid flow travels in a helical spiral, as centrifugal and hydrostatic forces balance the turbulent shear stress within the flow. Understanding the sense of the secondary flow circulation is important because the near bed orientation of the fluid flow vector strongly affects sediment transport and hence meander bend morphodynamic evolution, the patterns of surface grain size sorting and therefore the character of the sedimentary deposits produced. To evaluate the conditions favouring the onset of distinctive secondary flow circulations (and in particular, to discriminate cases when the near-bed radial flow is directed towards the inner bank ('river like') or outer bank ('river reversed'), we develop a holistic analytical model incorporating centrifugal and Coriolis forces, the radial pressure gradient and the baroclinicity of the flow. This new model is validated using experimental data and used to highlight the influence on the secondary flow of the principle physical forces acting on the flow. Previous analytical studies have considered a temporally constant, two-dimensional, rotationally invariant, framework that leads to vanishing radial material flux conditions when applied to flows within bounded channels. However, we show that a three-dimensional flow framework, with non-zero radial material fluxes resultant of flow super-elevation and overspill, is required to capture the rotational structure of flow within submarine meanders. Given this three-dimensional model, we present phase-space diagrams indicating the variation of the generic vertical structure of rotational flow within submarine meanders. Our findings highlight the importance of the radial flux boundary conditions as the primary control of secondary flow dynamics of submarine meanders. Further, the new model presented here suggests that the propensity for the occurrence of "river-reversed" secondary flow in canyon-fan networks is greater than recently

  16. Submarine fan sedimentation at a convergent margin: the cretaceous mangapokia formation, New Zealand

    NASA Astrophysics Data System (ADS)

    Barnes, Philip M.

    1988-10-01

    -concentration flows. Rare discontinuous graded bedded sandstones containing common flame structures (Facies 7) interbedded with conglomerate facies represent within-channel turbidites. A lower inner-submarine fan channel-overbank assemblage (Facies Association A), an inner-middle submarine fan channel-lobe assemblage (Facies Association B), and a mid-fan assemblage (Facies Association C) are distinguished. Two large-scale progradational suites of facies reflecting large-scale migration of the inner-fan channel complex are superimposed upon numerous small-scale depositional cycles resulting from lateral migration of numerous braided channels within the inner and mid-fan environments. The volumetrically minor ocean-floor assemblage is restricted to zones of melange. Chemically the basalts are tholeiitic, with trace element concentrations similar to modern ocean-floor basalts. Radiolarian-bearing cherts and coloured argillites are highly oxidised, and chemically similar to some modern oceanic pelagic sediments. The juxtaposition of relatively coherent, strongly folded and tectonically imbricated trench-fill submarine fan sediments and minor ocean-floor material is consistent with contemporaneous sedimentation and accretion at the base of the i inner trench slope in a convergent plate setting. The Mangapokia Formation is interpreted to represent the youngest part of the Torlesse terrane, and hence in southern North Island, Torlesse deposition and concurrent subduction tectonism were probably continuous at least until the middle Cretaceous.

  17. Concepts for future exploration for submarine fan and turbidite system reservoirs

    SciTech Connect

    Link, M.H.; Weimer, P. )

    1990-05-01

    With the emphasis of future petroleum exploration in deeper water and on frontier plays, submarine fan and turbidite systems will be major reservoir targets. Successful exploration and development of these reservoirs will be largely controlled by world oil prices, politics, markets, and drilling and producing technologies. Present economics require large reserves when targeting deep water or when drilling remote regions of countries that require large capital expenditures for pipelines and development. Future techniques for successful exploration and production of turbidite reservoirs will include (1) successful application of sequence stratigraphy in identifying reservoirs, (2) new play concepts for exploring synclinal low areas, and (3) the expanded use of three-dimensional seismic surveys. Lacustrine turbidites in rift, wrench, and successor basins are good potential targets because of their association with good source rocks/seals. Reservoirs occur at the base of deltaic clinoforms interbedded with source locks or along actively subsiding fault scarps. Many of these basins are extremely large, but the distribution of source rocks may be limited, making the potential reserves in these systems highly variable. Submarine fans associated with Cenozoic deltas remain an active deep water play. Turbidite reservoirs, deposited within bathymetric lows and localized basins on the slope created by salt and shale diapirism, occur in areas such as the northern Gulf of Mexico, continental margin of Nigeria, and Mackenzie Delta/Canadian Beaufort Sea. Other prospective Cenozoic delta-related margins include those associated with the Amazon, Indus, Ganges-Bramapuhtra, and Mahakam Deltas. The tremendous exploration successes in the deep-water Campos basin illustrate the great potential in passive margins. Targets are subtle and influenced by depositional topography controlled by growth faults, and shale and salt diapirs.

  18. Sedimentary facies analysis and depositional model of the Palaeogene West Crocker submarine fan system, NW Borneo

    NASA Astrophysics Data System (ADS)

    Zakaria, Abdullah Adli; Johnson, Howard D.; Jackson, Christopher A.-L.; Tongkul, Felix

    2013-10-01

    This study outlines a sedimentological analysis of the Palaeogene West Crocker Formation (WCF) around the Kota Kinabalu area of SW Sabah, which represents a large submarine fan depositional system within part of what was the complex and tectonically active margin of NW Borneo. The newly acquired and often extensive outcrop data summarised in this study has resulted in a more complete synthesis of the Crocker fan depositional system than has been previously possible. Seven facies (F1-F7) have been identified which constitute three main facies groups: (1) sand-dominated facies (F1-F3), comprise high- to low-density turbidites and form the dominant part of the WCF, (2) debris flow-dominated facies (F4-F6) comprises mud- and sand-dominant debris flows and mass transport deposits (MTD), which form a secondary but highly distinctive part of the WCF, and (3) mudstone-dominated facies (F7), represent a subordinate part of the WCF. Analysis of the vertical facies successions (from proximal to distal), has resulted in recognition of five major genetic units: (1) channel-levee complex; characterised by thick (30-60 m) thinning and fining upward facies succession, which are dominated in their lower part by thick-bedded (1-6 m), amalgamated high-density (Lowe-type) turbidites with rare debrite beds; the upper part is dominated low-density (Bouma-type) turbidites, without associated debrite beds. (2) Channelised lobes; characterised by 2-10 m thick, coarsening upward, which are overlain by 5-20 m thick fining upward facies successions; these successions are dominated by high-density turbidites (c. 0.5-1 m thick) and linked co-genetic turbidite-debrite beds (0.1-0.5 m thick), with subordinate mudstone facies. (3) Non-channelised lobes; comprise 5-20 m thick coarsening upward facies successions; these start with mudstone facies, which pass gradually upwards into linked co-genetic turbidite-debrite beds; sandstone bed thickness increases upwards, while the debrite caps tend to

  19. Mesozoic and late tertiary submarine fan sequences and their tectonic significance, Sumba, Indonesia

    NASA Astrophysics Data System (ADS)

    Von Der Borch, C. C.; Grady, A. E.; Hardjoprawiro, S.; Prasetyo, H.; Hadiwisastra, S.

    1983-12-01

    The Indonesian island of Sumba occupies a critical zone which separates a "normal" subduction complex (Java Trench System) from a continent-island arc collision zone (Banda Arc). Sumba is considered by some authors to be a microcontinental fragment, although in this context its pre-fragmentation origin is uncertain. Detailed studies of the stratigraphy of Sumba, however, throw light on the origin and subsequent geological history of the island and surrounding areas. On available evidence, the oldest outcropping rocks are of Cretaceous age and locally contain a tropical Tethyan marine fauna. They comprise dark-coloured, sometimes carbonaceous and often volcanogenic mudstones, sandstones, gravels and diamictites, pervasively intruded by andesitic and dacitic dykes and locally intruded by granodiorite plutons. These sediments are siliclastic and appear to have had a continental provenance. The Cretaceous rocks in many areas compromise part of a major submarine fan complex which, at least in south-central Sumba, prograded towards the southwest and south. Shallow marine and non-marine Paleogene sediments and volcanic agglomerates lie unconformably above the uplifted, tilted and eroded Cretaceous strata. These are overlain in turn by the widely outcropping Miocene Sumba Formation, an oceanic sequence with island-arc affinities. Accessible outcrops of the Sumba Formation comprise platform carbonates with abundant reef developments in west Sumba, and a major submarine fan—pelagic chalk complex in east Sumba. The fan complex, which extends beneath the southern Savu Sea north of Sumba, is dominated by large-scale slumps, olistostromes and thin- and thick-bedded turbidites. Turbidite sands and gravels invariably are volcaniclastic, containing components derived from a typical inner (volcanic) arc complex. Paleocurrent indicators are difficult to find in the Sumba Formation, thus it is uncertain at this stage whether the volcaniclastic turbidites were derived from the

  20. Effect of an offshore sinkhole perforation in a coastal confined aquifer on submarine groundwater discharge

    USGS Publications Warehouse

    Fratesi, S.E.; Leonard, V.; Sanford, W.E.

    2007-01-01

    In order to explore submarine groundwater discharge in the vicinity of karst features that penetrate the confining layer of an offshore, partially confined aquifer, we constructed a three-dimensional groundwater model using the SUTRA (Saturated-Unsaturated TRAnsport) variable-density groundwater flow model. We ran a parameter sensitivity analysis, testing the effects of recharge rates, permeabilities of the aquifer and confining layer, and thickness of the confining layer. In all simulations, less than 20% of the freshwater recharge for the entire model exits through the sinkhole. Recirculated seawater usually accounts for 10-30% of the total outflow from the model. Often, the sinkhole lies seaward of the transition zone and acts as a recharge feature for recirculating seawater. The permeability ratio between aquifer and confining layer influences the configuration of the freshwater wedge the most; as confining layer permeability decreases, the wedge lengthens and the fraction of total discharge exiting through the sinkhole increases. Copyright ?? 2007 IAHS Press.

  1. A delta-fed submarine ramp alternative to the canyon-fed depositional model of the Stevens submarine fan system, southeastern San Joaquin basin, Kern County, California

    SciTech Connect

    Harrison, C.P.

    1996-12-31

    Deep-marine sands of the Upper Miocene Stevens Sandstone, one of the most important hydrocarbon-producing units in the United States, were deposited by sediment-gravity flows in the Bakersfield Arch area of the southern San Joaquin basin. The Stevens Sandstone has historically been considered to be a thick turbidite succession shed off the southern Sierra Nevada as four fans in a long-lived submarine fan system fed by several large submarine canyons. Access to previously unavailable proprietary 2-D and 3-D seismic data sets, carefully calibrated by well-log and core data, permits a more complete understanding of the depositional architecture of this highly petroliferous, deep-marine depositional system. This study concludes that these units were deposited in a delta-fed, line- sourced deep-sea system, whose distribution was structurally-controlled. Seismic lines examined in this study show evidence for a large fault-controlled slump feature in the area that has been referred to as {open_quotes}Rosedale Canyon,{close_quotes} and no evidence supports the existence of submarine canyons feeding the system. The highly progradational Stevens interval consists of thick siliciclastic units separated by thin, intervening biosiliceous shales. Seismically, the upper bounding surfaces of these biosiliceous shales represent major downlap surfaces. As sands were deposited by high-density turbidity currents, the area of the present Bakersfield Arch developed into a deep-sea braid plain. Smaller-scale linear features detected on horizon slices through the 3-D seismic data cube have been interpreted in this study as braided channelform features deposited on the deep-sea braid plain. Hydrocarbon production along these linear trends may be associated with porosity and permeability variations resulting from channelized versus non-channelized sedimentation.

  2. A delta-fed submarine ramp alternative to the canyon-fed depositional model of the Stevens submarine fan system, southeastern San Joaquin basin, Kern County, California

    SciTech Connect

    Harrison, C.P. )

    1996-01-01

    Deep-marine sands of the Upper Miocene Stevens Sandstone, one of the most important hydrocarbon-producing units in the United States, were deposited by sediment-gravity flows in the Bakersfield Arch area of the southern San Joaquin basin. The Stevens Sandstone has historically been considered to be a thick turbidite succession shed off the southern Sierra Nevada as four fans in a long-lived submarine fan system fed by several large submarine canyons. Access to previously unavailable proprietary 2-D and 3-D seismic data sets, carefully calibrated by well-log and core data, permits a more complete understanding of the depositional architecture of this highly petroliferous, deep-marine depositional system. This study concludes that these units were deposited in a delta-fed, line- sourced deep-sea system, whose distribution was structurally-controlled. Seismic lines examined in this study show evidence for a large fault-controlled slump feature in the area that has been referred to as [open quotes]Rosedale Canyon,[close quotes] and no evidence supports the existence of submarine canyons feeding the system. The highly progradational Stevens interval consists of thick siliciclastic units separated by thin, intervening biosiliceous shales. Seismically, the upper bounding surfaces of these biosiliceous shales represent major downlap surfaces. As sands were deposited by high-density turbidity currents, the area of the present Bakersfield Arch developed into a deep-sea braid plain. Smaller-scale linear features detected on horizon slices through the 3-D seismic data cube have been interpreted in this study as braided channelform features deposited on the deep-sea braid plain. Hydrocarbon production along these linear trends may be associated with porosity and permeability variations resulting from channelized versus non-channelized sedimentation.

  3. Sequence architecture and lithofacies assemblages of submarine fan deposits in Los Molles Formation (Jurassic), Neuquen Basin, Argentina

    SciTech Connect

    Dean, J.S.

    1986-05-01

    The Neuquen basin is a remnant of the Mesozoic back-arc basin trend that developed along the western margin of South America. It contains a thick, diverse sequence of Jurassic sedimentary strata, whose facies distribution was strongly influenced by syndepositional tectonism. The predominantly dark, laminated shales and siltstones of the Los Molles Formation range from Pliensbachian to Callovian in age and record the progradation of the outer shelf, slope, and basin-plain sediments deposited during the shoaling phase of the lowermost, or Cuyan, Jurassic cycle. Based on outcrop, well, and seismic data, several thick packages of sandstone and conglomerate within the Los Molles are interpreted to represent submarine fan deposits that developed during periods of relative sea level lowstand. Sea level falls were probably related to local synchronous tectonic pulses rather than true eustatic fluctuations. The distribution of coarse-grained fan deposits was apparently strongly controlled by the location of major Jurassic fault trends that stabilized the position of the shelf-slope break through time. Based on the geometry and sequence architecture, two distinct styles of fan development are recognized in the Los Molles sandstones. The most common style (type A) is characterized by sequences that have poorly defined, sand-poor lobes with well-developed channel-levee complexes. Some channels exhibit large-scale accretion surfaces, probably resulting from lateral migration. Thick-bedded arenite facies are limited to amalgamated channel fills, whereas thin-bedded classical turbidites are present as overbank deposits. Type A fans were built by turbidity and fluxoturbidity currents from submarine canyon point sources. The less common fan sequences (type B) lack channeling; they are dominated by thick, massive beds of internally featureless sandstone that are bounded by chaotic slump deposits.

  4. Depositional characteristics of middle to upper Miocene Point Fermin Submarine Fan, Palos Verdes, California

    SciTech Connect

    Russell, P.W.

    1987-05-01

    The Point Fermin submarine fan lies within the upper Monterey Formation of the Palos Verdes Peninsula, California. Exposures of sediment gravity flow deposits extend from the upper portion of the tuffaceous lithofacies of the Altamira shale member to the middle of the Valmonte Diatomite. Outstanding sea-cliff exposures display a three-dimensional view of a large (approximately 1000 ft across) backfilled channel, scoured into thin-bedded shale and sandstone deposits. Channel backfill deposits primarily consist of Catalina schist-bearing sandstone and breccia, and lenses of disorganized intraformational breccia and conglomerate. The exposures exhibit an overall thinning and fining-upward sequence. The coarse-grained basal portion of the sequence displays sedimentary structures and bedding characteristics which are indicative of mass deposition by extremely concentrated, viscous dispersions. Channelized breccia beds contain schist clasts up to 9 ft in diameter, and intraformation breccia lenses contain rip-up clasts of Monterey Shale up to 30 ft long. Inferred flow mechanisms are a combination of grain flow, high-density turbulent flow, and sandy debris flow. The coarseness of these deposits is indicative of a proximal source. Higher in the sequence, sedimentary structures in upper portions of individual beds are characteristic of low-density turbulent flows. This upward change in sedimentary structures within individual beds is indicative of the passage of a high-density gravity flow and the subsequent waning, low-density turbulent flow conditions which follow. Directional features indicate a mean southeasterly flow direction. These results (which contradict data from previous published reports), in conjunction with the overall coarseness of these deposits, suggest the source to be the Palos Verde uplift.

  5. Geology and coproduction potential of submarine-fan deposits along the Gulf Coast of east Texas and Louisiana

    SciTech Connect

    Jackson, M.L.W.; Light, M.P.R.; Ayers, W.B. Jr.

    1987-04-01

    Four reservoirs containing dispersed gas were examined for their coproduction potential. Reservoirs in Port Acres field (Texas) and Ellis field (Louisiana) produce from the Hackberry member of the Oligocene Frio formation, and two reservoirs in Esther field (Louisiana) produced from the lower Miocene Planulina zone. Log-pattern and lithofacies maps, together with stratigraphic position, suggest that the reservoirs are in ancient submarine-fan deposits. Dip-elongate, channel-fill sands are characteristic; reservoir sands pinch out along the strike. Growth faults, common in the submarine slope setting, form undip and downdip boundaries, producing combination traps. In Ellis field, coproduction accounts for 300 Mcf/D (8.5X10/sup 3/ m/sup 3//d) of gas. Port Acres field contains the largest remaining reserves, but other technical and economic factors limit coproduction potential there. Recent drilling has extended primary production and delayed coproduction in the Esther field.

  6. Margin Architecture and Sediment Flux as Controls on Submarine Fan Development: Tectonic-Climate Interactions in the Gulf of Alaska

    NASA Astrophysics Data System (ADS)

    Gulick, S. P. S.; Montelli, A.; Swartz, J. M.; Morey, S.; Jaeger, J. M.; Mix, A. C.; Reece, R.; Somchat, K.; Wagner, P. F.; Worthington, L. L.

    2015-12-01

    The oblique collision of the Yakutat microplate into southeast Alaska generates the St. Elias Mountains, a coastal orogen with significant moisture from the Gulf of Alaska resulting in large, temperate glacial systems that expand to and eventually cross the continental shelf during glacial maxima. We present an overview of the evolution of sediment routing on this margin from integration of seismic images, updated age models and core-log-seismic correlations from IODP Expedition 341 drilling sites, and mapping efforts from shelf, slope, and fan. We focus on the three dominant glacial systems during the climatically important intensification of Northern Hemisphere glaciation at the Plio-Pleistocene transition and the further intensification of glaciation since the mid-Pleistocene transition. Along strike, sediment delivery to deepwater from the three glacial systems varied according to Pleistocene shelf accommodation space. The Alsek crossed a narrower shelf with a bedrock high near the shelf edge; the Malaspina-Hubbard system crossed an undeformed, ~1 km deep shelf; the Bering-Bagley system crossed a several km deep shelf deforming as an active fold and thrust belt. The Malaspina and Bering catchments exhibit high exhumation rates onshore due to the Yakutat collision and upon reaching the shelf edge these glaciers generate trough mouth fans (TMFs) on the adjacent continental slope but only after first filling the available accommodation with glacigenic sediment and lowering the slope gradient through progradation. The Alsek crosses the shelf earliest but never with sufficient sediment flux to generate a TMF. An east-west transition in adjacent deepwater submarine channels that feed and generate the Surveyor Fan suggests that shelf accommodation and sediment flux are primary controls on sediment routing from orogen to submarine fan. Both of these parameters are in turn a function of initial tectonic architecture and ongoing orogen dynamics.

  7. Potential links between onshore tectonics and terrestrial organic carbon delivery to distal submarine fan environments: IODP Site U1417, Surveyor Fan, Gulf of Alaska

    NASA Astrophysics Data System (ADS)

    Childress, L. B.; Ridgway, K. D.; Blair, N. E.; Bahlburg, H.; Berbel, G.; Cowan, E. A.; Forwick, M.; Gulick, S. P.; Jaeger, J. M.; Maerz, C.; McClymont, E.; Moy, C. M.; Müller, J.; Nakamura, A.; Ribeiro, F.

    2013-12-01

    and the older uplifted parts of the Mesozoic continental margin to the distal submarine fan system. Since the early Pleistocene, the distal fan has been sourced from tidewater glaciers transporting sediment from the continental margin of south-central Alaska through the Surveyor Channel and related sediment pathways, levees, and overbank systems. We hypothesize that tectonic transport of the Yakutat Terrane and the onset of tidewater glaciation resulted in variation of the geochemical signature of ancient carbon delivered to the distal parts of the Surveyor Fan. Biomarker differences between the Neogene coal-bearing Kulthieth Formation and the Mesozoic continental strata material will allow us to confirm source material to the fan over the last ~ 10 Ma.

  8. Growth of a post-Little Ice Age submarine fan, Glacier Bay, Alaska

    USGS Publications Warehouse

    Carlson, P.R.; Cowan, E.A.; Powell, R.D.; Cai, J.

    1999-01-01

    A small Holocene fan is forming where Queen Inlet, a hanging valley, enters West Arm fjord, Glacier Bay, Alaska. Queen fan formed in the last 80 years following retreat of the Little Ice Age glacier that filled Glacier Bay about 200 yr BP. It was built mainly by a turbidite system originating from Carroll Glacier delta, as the delta formed in the early 1900s at the head of Queen Inlet. The Late Holocene Queen fan is comparable to large Pleistocene fans that formed in the Gulf of Alaska and differs from trough-mouth fans formed by cooler climate glacier systems.

  9. Neogene marine sedimentary record of the Gulf of Alaska: from the glaciers to the distal submarine fan systems

    NASA Astrophysics Data System (ADS)

    Ridgway, K. D.; Bahlburg, H.; Childress, L. B.; Cowan, E. A.; Forwick, M.; Moy, C. M.; Müller, J.; Ribeiro, F.; Gupta, S.; Gulick, S. P.; Jaeger, J. M.

    2013-12-01

    The marine sedimentary record of Miocene to Pleistocene tectonics and glaciation is well preserved along the southern Alaska convergent margin. This margin is well suited for linking proximal to distal sediment transport processes because sediment is being generated by glacial erosion in the highest coastal mountain range on earth and subsequently being transported to the Aleutian subduction zone. We will discuss the sedimentary record from two end members of this system: (1) the proximal marine record now exposed onshore in the high peaks of the coastal ranges, and (2) the offshore distal record preserved in the Surveyor submarine fan system that was cored during the 2013 IODP Expedition 341. Onshore the Miocene non-glacial strata are represented by the Poul Creek Fm. This unit is 2000 m thick and in its upper part consists of mudstone, thin sandstone beds (10-30 cm thick), and thick bedded (1-2 m) highly bioturbated green sandstone beds that contain hummocky stratification. We interpret this unit as being deposited mainly in marine shelf environments. A gradational contact between the Poul Creek and the overlying upper Miocene-Pleistocene Yakataga Formation is marked by a transition to mudstone, thick bedded sandstone and glacial diamictite. This transition to glacial dominated deposition is interpreted to have occurred around 5 Ma based on previous studies. The onshore glacimarine strata are 5 km thick and grade up section from submarine fan to marine shelf strata. In the distal submarine fan record at IODP Site U1417, the upper Miocene strata in the lower part of the Site consist of 340 m of highly bioturbated gray to green mud interbedded with coarse sand and sandy diamict. These coarse-grained units are lithic rich with mainly sedimentary, volcanic, and coal clasts. We interpret these units as being derived from coal-bearing sedimentary strata exposed in the onshore thrust belt. These facies are interbedded with diatom ooze; we interpret this combination of

  10. Role of sediment supply and relative sea-level on sediment delivery to submarine deltas and fans of the Laurentian Channel (Lower St. Lawrence Estuary, Eastern Canada)

    NASA Astrophysics Data System (ADS)

    Normandeau, Alexandre; Lajeunesse, Patrick; St-Onge, Guillaume; Francus, Pierre

    2016-04-01

    Series of submarine canyons and channels observed in the Lower St. Lawrence Estuary (LSLE; Eastern Canada) provide an opportunity to analyze in great detail their morphology, spatial distribution and Holocene activity in a relatively shallow (≤300 m) semi-enclosed basin. Four categories of canyons and channels were identified according to their feeding sources: glacially-fed, river-fed, longshore drift-fed and sediment-starved systems. This presentation will focus on the interaction between glacially-fed, river-fed (deltas) and longshore drift-fed systems. Three main types of deposits were identified in sediment core samples and seismic stratigraphy: turbidites, debrites and hyperpycnites. The analysis of high-resolution multibeam data, seismic profiles and sediment cores reveals the differences in timing of these gravity flow deposits related to submarine fan deposition. Submarine fans related to glacial meltwaters were formed during deglaciation, near 11 ka cal BP. Following the retreat of the Laurentide Ice Sheet margin in the LSLE, delta progradation allowed the formation of submarine channels by debris and hyperpycnal flows. A reduction of sediment supply from the rivers and a relative sea-level stabilization by 7 ka cal BP then limited the occurrence of these debris and hyperpycnal flows and favoured erosion of the delta fronts. During delta progradation, longshore drift-fed submarine fans were also formed due to high sediment supply, but continued transferring terrigenous material throughout the Holocene. This continued activity was possible because delta fronts eroded and longshore drift transported sediments to the canyons located at the end of a littoral cell. This study highlights that the variability and timing of sediment deposition in submarine deltas and fans is controlled primarily by variations in sediment supply in a formerly glaciated environment.

  11. Mesoscale mechanics of distributive channel systems with supercritical distributaries: an experimental study of alluvial and submarine fans

    NASA Astrophysics Data System (ADS)

    Hamilton, Paul; Strom, Kyle; Hoyal, David

    2014-05-01

    Cyclicity is a feature of distributive channel systems whereby the landform is modified by either: variation in boundary conditions, e.g., sea-level rise/fall on deltas, or feedbacks triggered and maintained by intrinsic system mechanics, i.e., autogenic processes. The intrinsic organization of coupled fluid/sediment systems is predictable over small scales, i.e., bedform development and evolution; similar relationships can be developed for sedimentary systems over the mesoscale, i.e., the channel and lobe scale. The most prevalent mesoscale process at work in a variety of settings is the avulsion cycle which takes a generic form of: distributive channel formation and basinward extension, deceleration and mouth bar deposition, flow interaction with the aggrading mouth bar and upstream retreat, and flow reorganization. Though this generic description holds in a general sense, a system's particular response is a function of several variables but is most deterministically tied to hydraulic regime relative to critical flow. Herein we describe the supercritical autogenic response of fan systems using experimental results that include data pertaining to both phases of the morphodynamic feedback cycle, the fluid flow and the mobile sediment bed. Non-invasive, image-based techniques were used to quantify the velocity field on evolving fans. Hydraulic characterization is combined with topographic scans to create a complete picture of mesoscale development. This combination makes for a unique data set in mesoscale geomorphology experiments where data is typically restricted to topography evolution with inferred hydraulic process. Via experiments we show that supercritical distributaries experience hydraulic jump controlled backfilling and avulsion as distinguished from the backwater controlled avulsions occurring with subcritical distributive systems. Further, we consider both alluvial and submarine fan experiments to better examine the relative importance of setting

  12. Late Pleistocene channel-levee development on Monterey submarine fan, central California

    USGS Publications Warehouse

    Normark, W.R.

    1999-01-01

    Much of the modern upper (proximal) Monterey fan is a channel-levee complex, the Upper Turbidite Sequence (UTS), that was deeply eroded after the channel breached a volcanic ridge to reach a deeper base level. Ages of sediment samples collected with the ALVIN submersible from the deepest outcrop within the channel-levee system, 390 m below the adjacent western levee crest, indicate that the UTS deposits accumulated at ???1 m ka-1 during the last 500 ka. Neogene and Early Pleistocene sediment accumulation on the fan prior to the UTS was much slower (<0.03 m ka-1), and underlying turbidite systems(?) had substantially different morphologic expression(s).

  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

    SciTech Connect

    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. Cenozoic Climate-Tectonic Interactions in the Western Himalaya Recorded in the Indus Submarine Fan from IODP Expedition 355

    NASA Astrophysics Data System (ADS)

    Clift, P. D.; Pandey, D.; Kulhanek, D. K.; Andò, S.; Science Party, E.

    2015-12-01

    The Indus Submarine Fan is the largest repository of clastic sediment eroded from the Western Himalayas since the start of India-Eurasia collision likely around 50 Ma. This sedimentary archiveis central to understanding how the climate and the tectonic evolution of the mountains have evolved together. A number of models now propose linkages between surface processes, controlled by climatic influences, and the tectonics of the solid Earth. In particular, exhumation of deeply-buried high-grade metamorphic rocks in the Greater Himalaya and the development of large-scale duplexes within the Lesser Himalaya are likely triggered by changes in the rate and location of erosion. Although some of these issues can be addressed by studies onshore, erosion has removed much of the older record from the crystalline basement itself. As a result the sediment record must be used to understand how fast erosion was occurring and whether that was linked to changes in tectonics and climate. A major unconformity in the foreland basin means that this work cannot be done fully using terrestrial records but rather the more complete records in the Arabian Sea and Bay of Bengal. Drilling by International Ocean Discovery Program Expedition 355 in the Eastern Arabian Sea has recovered two sections spanning the last ~11 Ma, which should allow us to reconstruct how the Western Himalaya have responded to climate change since the late Miocene, spanning the time when the Lesser Himalaya began to exhume. Autocyclic processes within the fan and a major mass transport deposit mean that the record is not continuous, but should nonetheless allow us to examine the impact of the important climatic transition at 7-8 Ma noted on the Oman margin and in the foreland basin. Initial results indicate that the Indus Fan was receiving material from Himalayan high-grade metamorphic rocks since at least ca. 14-17 Ma and that there was a direct connection with the suture, likely close to the western syntaxis, dating

  15. Cenozoic Climate-Tectonic Interactions in the Western Himalaya Recorded in the Indus Submarine Fan: Initial Results from IODP Expedition 355

    NASA Astrophysics Data System (ADS)

    Clift, Peter; Pandey, Dhananjai; Kulhanek, Denise; Andò, Sergio; Zhou, Peng; 355 Scientists Expedition

    2016-04-01

    The Indus Submarine Fan is the largest repository of clastic sediment eroded from the Western Himalayas since the start of India-Eurasia collision, likely around 50 Ma. Interpreting this sedimentary archive is central to understanding how the Asian monsoon and Himalaya have evolved together. Models indicate linkages between surface processes, controlled by climatic influences, and the tectonics of the solid Earth. The development of large-scale duplexes within the Lesser Himalaya starting in the Late Miocene may be linked to changes in erosion intensity and location, especially spanning the 7-8 Ma climatic transition previously identified in the foreland basin and offshore Oman. Although some of these issues can be addressed by studies onshore, erosion has removed much of the older record from the crystalline basement itself and the Siwalik Group foreland sediment tend to image limited stretches of the Himalayan front rather than supplying a basin-wide record. The sediment record of the Arabian Sea must be used to understand how the Indus catchment responds to changes in monsoon strength. Drilling by International Ocean Discovery Program Expedition 355 in the Eastern Arabian Sea has recovered two submarine fan sections spanning the last ca. 11 Ma, predated by a mass transport deposit. These should allow us to reconstruct how the Western Himalaya have responded to climate change since the late Miocene. Autocyclic processes within the fan and a major mass transport deposit mean that the record is not continuous, but is largely complete. Initial results indicate that the Indus Submarine Fan was receiving materials from Himalayan high-grade metamorphic rocks since at least ca. 14-17 Ma and that there was a direct connection with the suture, likely close to the western syntaxis, dating from the late Miocene. However, initial postcruise results now indicate that there has been significant flux directly from the Indian Peninsular, especially since 3 Ma that disrupts the

  16. Occupational stress in submariners: the impact of isolated and confined work on psychological well-being.

    PubMed

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

    NASA Astrophysics Data System (ADS)

    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

  18. The origin and internal structures of submarine-slide deposits in a lower Pleistocene outer-fan succession in the Kazusa forearc basin on the Boso Peninsula of Japan

    NASA Astrophysics Data System (ADS)

    Fukuda, Kayo; Suzuki, Masahiro; Ito, Makoto

    2015-05-01

    This study investigates the internal geometry and formation processes of submarine-slide deposits in a lower Pleistocene outer-fan succession in the Kazusa forearc basin on the Boso Peninsula of Japan. The submarine-slide deposits are ~ 40 m thick, with a minimum length of ~ 900 m and a width of ~ 700 m. Both the submarine-slide deposits and host deposits comprise siltstones intercalated with very thin- to medium-bedded, sheet-like turbidites and volcanic ash beds. Based on the sequence-stratigraphic framework of the submarine-fan succession, we conclude that the submarine-slide deposits formed during a glacioeustatic sea-level lowstand at about 1.16 Ma. The submarine-slide deposits are characterized by thrust sequences with a ramp anticline in the frontal part. A basal slide plane in the lower part of the deposits is developed at a horizon located 2-4 cm below the base of a coarse volcanic ash bed and is associated with sheared deposits. Slide planes are sealed in the upper part of the submarine-slide deposits in association with drag folds and chaotic deposits. Finally, the submarine-slide deposits are transitionally overlain by ~ 3-m-thick chaotic muddy deposits, and are finally overlain by siltstones intercalated with very thin- to medium-bedded, sheet-like turbidites and volcanic ash beds, which show lithofacies features similar to those of the submarine-slide deposits. The variations in the deformation styles indicate that sliding occurred as a synsedimentary process in the outer-fan environment, and the basal slide plane formed when the porosity of the muddy deposits was reduced to ~ 55% or less. Based on the empirical relationship between the submarine-fan length and lower-fan slopes from modern examples, the gradient of the outer-fan is estimated at 0.31°-0.46°, which is lower than the threshold gradient of 1.2° for a 40-m-thick submarine slide with the estimated basal porosity. Based on the distribution of deformed deposits within the lower-fan host

  19. Facies and cyclicity within the Oligocene-Early Miocene Panjgur Formation, Khojak-Panjgur Submarine Fan Complex, south-west Makran, Pakistan

    NASA Astrophysics Data System (ADS)

    Kassi, Akhtar Muhammad; Khan, Abdul Salam; Kelling, Gilbert; Kasi, Aimal Khan

    2011-06-01

    The Makran Accretionary Belt covers vast areas of the south-western Makran, Pakistan and extends westwards into coastal Iran. In Pakistan this belt is dominated by an overall regressive succession comprising the Siahan/Hoshab shale (a valley-forming claystone/siltstone-dominant facies) and the ridge-forming, sandstone-dominant facies of the Panjgur Formation, a very thick cyclic succession of Oligocene-Early Miocene turbidites. These formations form part of the "Khojak-Panjgur Submarine Fan Complex". The Panjgur Formation comprises nine distinct facies, which are organized into seven facies associations distinguished by their constituent facies, vertical organizations and lateral geometries. Facies associations include: (1) mid-fan channels, (2) overbank/levee, (3) crevasse-splays, (4) inter-channel, (5) outer-fan-lobes, (6) fan-fringe, and (7) trench floor/basin-plain. The formation displays a hierarchy of 1st, 2nd and 3rd order sedimentary cycles. The 1st order cycles range in thickness from 60 m to 450 m and conceptually correspond to "sequences" or "depositional sequences" formed mainly in response to sea-level fluctuations. Their boundaries are characterized by gradual or abrupt replacement of claystone/siltstone facies of the basin-plain by thin- to thick-bedded mid- to outer-fan turbidites, representing a basinward shift of the facies. The 1st order cycles generally start with thick- to very thick-bedded sandstones of channelized mid-fan facies, passing upwards into a middle part consisting of thin- to thick-bedded sandstone and claystone facies of the outer-fan-lobes and capped by claystone/siltstone-dominant facies of the basin-plain association. These three parts of the 1st order cycles correspond to the lowstand systems tracts (LST), transgressive systems tracts (TST) and highstand systems tract (HST) of the full depositional sequence. The 2nd order cycles, which are generally thinning-up and thickening-up cycles, range in thickness from 4 to 65 m, and

  20. Provenance of a large Lower Cretaceous turbidite submarine fan complex on the active Laurasian margin: Central Pontides, northern Turkey

    NASA Astrophysics Data System (ADS)

    Akdoğan, Remziye; Okay, Aral I.; Sunal, Gürsel; Tari, Gabor; Meinhold, Guido; Kylander-Clark, Andrew R. C.

    2017-02-01

    The Pontides formed the southern active margin of Laurasia during the Mesozoic. They became separated from mainland Laurasia during the Late Cretaceous, with the opening of the Black Sea as an oceanic back-arc basin. During the Early Cretaceous, a large submarine turbidite fan complex developed in the Central Pontides. The turbidites cover an area of 400 km by 90 km with a thickness of more than 2 km. We have investigated the provenance of these turbidites-the Çağlayan Formation-using paleocurrent measurements, U-Pb detrital zircon ages, REE abundances of dated zircons and geochemistry of detrital rutile grains. 1924 paleocurrent measurements from 96 outcrop stations indicate flow direction from northwest to southeast in the eastern part of the Çağlayan Basin and from north-northeast to west-southwest in the western part. 1194 detrital zircon ages from 13 Lower Cretaceous sandstone samples show different patterns in the eastern, central and western parts of the basin. The majority of the U-Pb detrital zircon ages in the eastern part of the basin are Archean and Paleoproterozoic (61% of all zircon ages, 337 grains); rocks of these ages are absent in the Pontides and present in the Ukrainian Shield, which indicates a source north of the Black Sea. In the western part of the basin the majority of the zircons are Carboniferous and Neoproterozoic (68%, 246 grains) implying more local sources within the Pontides. The detrital zircons from the central part show an age spectrum as mixture of zircons from western and eastern parts. Significantly, Jurassic and Early Cretaceous zircons make up less than 2% of the total zircon population, which implies lack of a coeval magmatic arc in the region. This is compatible with the absence of the Lower Cretaceous granites in the Pontides. Thus, although the Çağlayan Basin occupied a fore-arc position above the subduction zone, the arc was missing, probably due to flat subduction, and the basin was largely fed from the Ukrainian

  1. Complications in The Identification and Mapping of the Foot of the Slope on the Indus Submarine Fan

    NASA Astrophysics Data System (ADS)

    Inam, A.; Rabbani, M. M.; Tabrez, A. R.

    2005-12-01

    scientific literature. The investigation and identification of the COB/COT/SDRs might be one of the most critical element in determining the FoS using geological/geophysical evidence, when invoking the `evidence to the contrary' provision of the Art.76 for the establishment of the continental shelf. The seafloor spreading, basement topography and the SW Monsoon have influenced the sediment deposition in the geological past, resulting in variable sediment thicknesses in the area. This will be one of the most critical factor when pursuing the `sediment thickness rule' for the proposed establishment of the continental shelf. The rugged bottom topography and variations in the sediment thicknesses over the Indus submarine fan has made the delimitation of marine boundary a very challenging task for the scientists involved in the application of Article 76 in this part of the world.

  2. Structural controls on the development of submarine channel/fan systems since the Pleistocene in the accretionary wedge off SW Taiwan

    NASA Astrophysics Data System (ADS)

    Shen, Kang-Nien; Tien-Shun Lin, Andrew; Lin, Che-Chuan; Liu, Char-Shine; Wang, Yunshuen

    2016-04-01

    The accretionary wedge off SW Taiwan is the result of incipient arc-continent collision between the Luzon volcanic arc and the northern rifted margin of the South China Sea (SCS). Dynamic interactions of thrusting, folding and a rigorous sediment supply from the Taiwan mountain belts have resulted in two arrays of canyons/channels and slope-fan systems in the accretionary wedge. The Penghu canyon/fan system lies in the lower wedge and near the northern rifted margin of the SCS. The Penghu canyon is a river-fed canyon and receives sediments from southern Taiwan and SE China during eustatic lowstands. It becomes detached from river inputs during eustatic highstands as it is in the present-day. The Gaoping canyon/fan system in the south traverses both the upper slope and lower slope domains of the accretionary wedge. This system is a river-fed system during a full eustatic cycle and it drains sediments from the onshore Gaoping River. We interpreted multiple grids of multichannel seismic reflection data of MCS994, MCS1000-6, MCS1014, MCS1046 collected onboard Ocean Research I during 2012 April to 2013 August to map out thrust/fold structures and channel/fan systems in the study area. Seismic facies analyses were performed on seismic sections and key stratal surfaces of base of Pliocene and base of Pleistocene are correlated from boreholes drilled in the shelf of the northern SCS margin. Our results show that the upper Gaoping Canyon has been confined by structural ridges with limited switching of canyon courses, whereas the lower Gaoping canyon/fan system has been developed on lower slope with channel/levee deposition in multiple slope fans since early Pleistocene. Pleistocene lateral aggrading channel-and-levee systems are especially evident near the modern canyon course in the lower slope. The Penghu can/fan system in the lower accretionary wedge is also evident by seismic facies showing channel cut-and-fill, channel abandonment and channel-and-levee systems. This

  3. Provenance of Miocene submarine fans in the Shikoku Basin: Results from NanTroSEIZE and implications for stratigraphic correlation of subduction inputs

    NASA Astrophysics Data System (ADS)

    Pickering, K. T.; Underwood, M.; Moore, G. F.

    2013-12-01

    Seismo-stratigraphy, coring and LWD during IODP Expeditions 319, 322, and 333 (Sites C0011 / C0012) show three Miocene submarine fans in the NE Shikoku Basin, with broadly coeval deposits at ODP Site 1177 and DSDP Site 297, NW Shikoku Basin. Pickering et al. (2013) have shown that the sediment dispersal patterns for these fans have major implications for paleogeographies at that time. The oldest, Middle Miocene Kyushu Fan is the finest grained, has a sheet-like geometry, and was fed by quartz-rich sediment gravity-flows derived mostly from an ancestral landmass in the East China Sea. This likely sediment provenance is further supported by U-Pb zircon and fission track analysis of both zircons and apatites from sediments taken from the forearc and trench of the Nankai Trough, together with rivers from southwest Japan, that point to the influence of the Yangtze River in supplying into the Shikoku Basin prior to rifting of the Okinawa Trough at 10 to 6 Ma (Clift et al. 2013). During prolonged hemipelagic mud deposition at C0011-C0012 (12.2 to 9.1 Ma), sand supply continued at Sites 1177 and 297. Sand delivery to much of the Shikoku Basin, however, probably halted during a phase of sinistral strike-slip and oblique plate motion, after which the Daiichi Zenisu Fan (9.1 to 8.0 Ma) was fed by submarine channels. The youngest fan (Daini Zenisu; 8.0 to 7.6 Ma) has sheet-like geometry with thick-bedded, coarse-grained pumiceous sandstones. The pumice fragments were fed from a mixed provenance that included the collision zone of the Izu-Bonin and Honshu arcs. The shift from channelized to sheet-like flows was probably favored by renewal of relatively rapid northward subduction, which accentuated the trench as a bathymetric depression. Understanding the stratigraphic position and 3-D geometry of the sandbodies has important implications for stratigraphic correlation throughout the northern Shikoku Basin, together with subduction-related processes, including the potential for

  4. Proto-Pacific-margin source for the Ordovician turbidite submarine fan, Lachlan Orogen, southeast Australia: Geochemical constraints

    NASA Astrophysics Data System (ADS)

    Offler, R.; Fergusson, C. L.

    2016-04-01

    The Early Palaeozoic proto-Pacific Pacific margin of Gondwana was characterised by a huge turbidite submarine fan with abundant clastic detritus derived from unknown sources within Gondwana. These deposits are widespread in the Lachlan Orogen of southeast Australia and include the Ordovician Adaminaby Group. Here we show that the mudstones and sandstones of the Adaminaby Group have chemical compositions that indicate the detritus in them was derived from a felsic, continental source similar in composition to Post Archean Australian Shales (PAAS). Chondrite normalised REE patterns showing LREE enrichment, flat PAAS normalised patterns and elemental ratios La/Sc, Cr/Th, Cr/V, Th/Sc and Th/U, have been used to support this interpretation. The dominance of quartz, and to a lesser degree plagioclase and biotite in the sandstones, suggests that the source was mainly granodioritic to tonalitic in composition. Th/Yb and Ta/Yb ratios indicate that the source was probably calc-alkaline, continental and shoshonitic. In addition, the presence of detrital muscovite, low-grade metamorphic and felsic volcanic clasts, demonstrates that a low-grade metamorphic terrane and volcanic arc contributed to the detritus observed in the samples. The presence of well-rounded zircons and tourmalines, very high Zr contents, high Zr/Sc and higher Cr/V ratios in some samples particularly in the Shoalhaven River area, indicate that some of the detritus was recycled. SiO2 versus (Al2O3 + K2O + Na2O) plots suggest the source areas experienced conditions varying from humid/semi-humid to semi-arid. Textural features and weathering trends of samples from all locations follow a curved pathway on Al2O3 - (CaO* + Na2O) - K2O (ACNK) diagrams, and indicate that the clays formed from weathering had been K-metasomatised prior to penetrative deformation. Chemical indices of alteration (CIA) reveal that even the freshest sandstones are altered and others are moderately to strongly altered. Discrimination

  5. Meander in valley crossing a deep-ocean fan.

    PubMed

    Shepard, F P

    1966-10-21

    Seaward of most submarine canyons there are large sediment fans comparable to the fans at the base of mountain ranges. Many of the submarine fans are cut by valleys called fan-valleys which usually connect with the mouths of submarine canyons. Loop-like bends or meanders characterize the channels of rivers in their lower flood plains, but have never been found in the shallow channels that cross the alluvial fans at the base of mountain canyons. Therefore, it was surprising to find that the channel in a very deep submarine fan-valley off Monterey Bay, California, has a tight meander.

  6. Present Thoughts on Exercise, Weight, and Performance Aboard Nuclear Submarines,

    DTIC Science & Technology

    Submarine personnel, Physical fitness, Confined environments, Stress(Physiology), Stress(Psychology), Body weight, Weight reduction, Diet , Nuclear powered submarines, Exercise(Physiology), Performance(Human)

  7. Sequence stratigraphy and depositional systems of the paleocene submarine fans in the central North Sea: The evolution of a shelf-to-basin system

    SciTech Connect

    Reinsborough, B.C.; Galloway, W.E. )

    1993-09-01

    Slope/basin depositional systems consist of combinations of facies, including slump lobes; chute, flute, and channel fills; mounded turbidite lobes; sheet turbidites; low-density turbidite sheets and fills; hemipelagic drapes; and contourite mounds. Specific facies associations are determined by the nature (point source or linear source) and caliber (volume, grain size, sand:mud) of sediment supply to the slope. The extensive well-log, seismic, and core database was used to dissect the stratal and facies architecture of the Andrew depositional system and characterize a logical evolution of the sand-rich shelf-to-basin depositional systems tract. The andrew consists of upper and lower depositional units bounded by downlap terminations and high-gamma marker beds. The lower Andrew displays three distinct sand-rich lobes, delineated by isopach, sand percent, log motif, and seismic facies maps Proximal, mounded, sand-rich units disperse into unchannelized sheet turbidites in the basin. No extensive incised submarine valleys feed this unit, which is characterized by coarsening and thickening-upward log responses and hummocky to discontinuous reflectors. The upper Andrew downlaps the lower unit and a single, linear sediments source was centered in the Witch ground graben. The dispersal pattern and internal character suggest the upper unit is a proximal slope apron, downlapping and filling interlobe bathymetric lows of the underlying unit. Sharp-based, blocky/digitate log signatures, discontinuous chaotic reflectors, and coarse-grained sediment characterize this unit. The lower Andrew represents a structurally focused, sand-rich lobe complex, without associated incised canyons. The Andrew system evolved as the delta platform expanded onto the proximal fan, resulting in a linear sediment source spilling over the slope as a fringing slope apron.

  8. The Astoria Fan: An elongate type fan

    USGS Publications Warehouse

    Nelson, C.H.

    1984-01-01

    The Astoria Fan, a modern system, is located on a subducting oceanic crust and fills a north-south-trending trench along the Oregon continental margin. Well-developed channels cross the entire fan length; they display classic inner-fan leveed profiles but evolve into distributaries in the midfan area where the gradient decreases sharply. During periods of low sea level, inner- and middle-fan channels funnel sand to distal depositional sites in the outer-fan area where the sand/shale ratios are highest. This pattern of sand displacement and efficiency of transport appears to be characteristic of elongate fans fed by a major river and submarine canyon. ?? 1984 Springer-Verlag New York Inc.

  9. Miocene Blanca Fan, Northern Channel Islands, California: Small fans reflecting tectonism and volcanism

    NASA Astrophysics Data System (ADS)

    McLean, Hugh; Howell, D. G.

    1984-06-01

    Blanca fan is a submarine fan composed of Miocene volcaniclastic strata. Parts of the fan system are exposed on Santa Cruz and Santa Rosa Islands, and possibly correlative strata crop out on San Miguel and Santa Catalina Islands. The Blanca fan and underlying breccia reflect regional transcurrent faulting in the California Continental Borderland and development of a system of rapidly subsiding basins and uplifted linear ridges during early and middle Miocene time. Erosion of uplifted crystalline basement rocks followed by the onset of silicic volcanism created linear sediment sources for the alluvial and submarine fans, respectively.

  10. Miocene Blanca Fan, Northern Channel Islands, California: Small fans reflecting tectonism and volcanism

    USGS Publications Warehouse

    McLean, H.; Howell, D.G.

    1984-01-01

    Blanca fan is a submarine fan composed of Miocene volcaniclastic strata. Parts of the fan system are exposed on Santa Cruz and Santa Rosa Islands, and possibly correlative strata crop out on San Miguel and Santa Catalina Islands. The Blanca fan and underlying breccia reflect regional transcurrent faulting in the California Continental Borderland and development of a system of rapidly subsiding basins and uplifted linear ridges during early and middle Miocene time. Erosion of uplifted crystalline basement rocks followed by the onset of silicic volcanism created linear sediment sources for the alluvial and submarine fans, respectively. ?? 1984 Springer-Verlag New York Inc.

  11. High-resolution seismic stratigraphy of a late Pleistocene submarine fan ponded by salt-withdrawal mini-basins on the Gulf of Mexico continental slope

    SciTech Connect

    Winker, C.D.

    1996-12-31

    The late Pleistocene Brazos-Trinity Fan, a structurally ponded fan completely exposed and undisturbed on the seafloor, was mapped with a combination of conventional and high-resolution seismic data. This fan occupies three salt-withdrawal mini-basins (1, 2, 4) and a graben (3), each filled with an onlapping package consisting of alternating bedded and non-bedded units evident on high-resolution data. Basins 1--3 are filled to their topographic spill points; the onlap-fill succession of each is incised by a channel system which bypassed sediment to the next basin(s) downdip. Seismic continuity generally increases distally in the system and within individual basins, believed to reflect the increasing prevalence of turbidity currents over high-density sediment gravity flows.

  12. Slope-confined submarine canyons in the Baiyun deep-water area, northern South China Sea: variation in their modern morphology

    NASA Astrophysics Data System (ADS)

    Li, X. S.; Zhou, Q. J.; Su, T. Y.; Liu, L. J.; Gao, S.; Zhou, S. W.

    2016-06-01

    On the basis of newly collected multibeam bathymetric data, chirp profiles and existing seismic data, we presented a detailed morphological interpretation of a series of slope-confined canyons in water depths of 300-2000 m in the Baiyun deep-water area, northern margin of the South China Sea. Although these canyons are commonly characterized by regular spacing and a straight-line shape, they vary in their lengths, starting and ending water depths, canyon relief, slope gradients, wall slope gradients and depth profiles along the axis. The eastern canyons (C1-C8) have complex surface features, low values in their slope gradient, canyon relief and wall slope gradient and high values in their length and starting and ending depth contrasting to the western ones (C9-C17). From the bathymetric data and chirp profiles, we interpret two main processes that have controlled the morphology and evolution of the canyons: axial incision and landsliding. The western part of the shelf margin where there were at least four stages of submerged reefs differs from the eastern part of the shelf margin where sedimentary undulations occurred at a water depth of ~650 m. We consider that the variation in morphology of submarine canyons in the study area is the result of multiple causes, with the leading cause being the difference in stability of the upper slope which is related to the submerged reefs and sedimentary undulations.

  13. Characteristics of weakly confined submarine channel system and their application to gas hydrate trapping system, Eastern Nankai Trough, Japan

    NASA Astrophysics Data System (ADS)

    Komatsu, Y.; Fujii, T.; Suzuki, K.

    2013-12-01

    The 1st offshore gas hydrate production test was conducted at gas hydrate concentrated zone (reservoir) of the Eastern Nankai Trough, which is considered stratigraphic accumulation. However, the accumulation mechanism for this concentrated zone is not yet well understood. In this study, in order to examine gas hydrate trapping system in the accumulation mechanism, we identify the depositional process and controlling factors based on facies analysis and sequence stratigraphy using the core and geophysical log data. Our study area is the minibasin in the front of the north slope of Daini-Atsumi Knoll in the Eastern Nankai Trough. The minibasin development is strongly influenced by uplift of the knoll associated with plate subduction. The minibasin fill deposits are interpreted as the Pleistocene trough fill small turbidite fan system. Seven depositional sequences are identified based on grain size, bed thickness, sedimentary structure, and stacking pattern in this study. The sequence boundaries are also identified by terminations of seismic reflection. These sequences are attributed to a fourth to fifth-order eustatic sea-level changes, because the stacking pattern cycle is in phase with global oxygen isotope curves, the cycle is also identified in the onshore formation during the same period. The reservoir was interpreted as Falling-Stage Systems Tract (FSST) and Lowstand Systems Tract (LST). In the reservoir, it was observed the channel complex set characterized by relatively strong reflections and paleocurrent flowing from northeast to southwest on 3-D seismic data. The channel complex set changes into muddy facies in the south direction. The channel complex set is characterized by hemipelagic setting or slope (F1), abandonment mud drape (F2), nonamalgamated channel element (F3), and semiamalgamated channel element (F4). The channel elements (F3, 4) are the fundamental unit and record a single phase of downcutting and filling. The building block of the channel

  14. Lithofacies, biofacies, and ichnoassemblage evolution of a shallow submarine volcaniclastic fan-shelf depositional system (Upper Cretaceous, James Ross Island, Antarctica)

    NASA Astrophysics Data System (ADS)

    Scasso, R. A.; Olivero, E. B.; Buatois, L. A.

    The Upper Cretaceous (Santonian-Campanian/lower Maastrichtian) Santa Marta Formation on James Ross Island, Antarctica, represents volcaniclastic shallow marine fan and shelf sedimentation adjacent to an active volcanic arc. A combined analysis of sedimentologic, paleoecologic, and ichnologic data allows for the recognition in this unit of six lithofacies associations, eight biofacies, and five trace fossils assemblages. Lithofacies are dominated by fine, massive, tuffaceous rocks; graded, turbidite-like tuffaceous sandstones; carbonaceous mudstones; resedimented conglomerates; coquinas; sandstones; silty sandstones; and minor stromatolite beds. Biofacies are defined by different composition and relative abundance of elements of the benthic fauna, mainly bivalves, gastropods, and serpulids, with minor elements represented by scaphopods, corals, brachiopods, and echinoids. Trace fossil assemblages include the most common elements of the Skolithos and Cruziana ichnofacies. A striking result of the analysis is that lithofacies, biofacies, and trace fossil assemblages form distinct, non-repetitive, vertically successive horizons, with their distribution boundaries roughly coincident. On this basis, seven major facies groups, showing a distinct combination of lithofacies, biofacies, and trace fossils, are distinguished in the Santa Marta Formation. These non-repetitive, vertically stacked facies groups reveal a one-way evolution of the depositional system during a transgressive-regressive cycle, with a new transgression at the top of the unit. The lower facies groups represent shallow marine settings with a very high rate of volcaniclastic sedimentation within subsiding basin. Shallow, volcaniclastic fan systems were probably formed at the base of delta slope and grew rapidly as a consequence of high sedimentary supply in equilibrium with basin subsidence. The upper facies groups probably represent sedimentation within the marine part of the envisaged deltaic system on a

  15. Delivery of Terrigenous Material to Submarine Fans: Biological Evidence of Local, Staged, and Possibly Full Canyon Sediment Transport Down the Ascension-Monterey Canyon System Off Central California, USA

    NASA Astrophysics Data System (ADS)

    McGann, M.

    2014-12-01

    Submarine canyons are instrumental in transporting sediment from coastal regions to deep-sea fans. Mean grain size, distribution, and sorting have been used to characterize these deposits, but they provide little information on where sediment transport was initiated or the delivery processes involved. Fortunately, the entrained biological constituents have unique environmental signatures that are more precise proxies for source areas than are mineral grains alone. They may identify a single biofacies deposit (SBD) resulting from local sediment transport such as storm waves, peak river discharge, breaking of internal waves, canyon wall sloughing, or hemipelagic deposition, or a displaced, multiple biofacies deposit (MBD) containing several biofacies where sediment is transported from one biofacies to another, is caught behind a slump that acts as a dam, remains there long enough for the local fauna to become established, and then this combined assemblage is transported further downslope when the dam breaks. Multiple episodes of this "staged" storage-and-release process occur sequentially so as to move the sediment progressively down the canyon. Rarely, exceptionally large triggers such as earthquakes, intense storm disturbances, and catastrophic failure of canyon walls result in full canyon flushing events, entraining numerous biofacies during a single rapid descent. These events can be differentiated in recent deposits by the presence of living specimens representing distinct biofacies or in historic records by dating individual biofacies within a turbidite. A 19,000 year record from the Ascension-Monterey Canyon system (core S3-15G, 36°23.53'N, 123°20.52'W; 3491 m) captured hemipelagic mud interspersed with turbiditic sand and silt transported to lower bathyal depths. The relative abundance of displaced benthic foraminifera was found to correlate positively with grain size (75% in cross-bedded turbiditic sands, 39% in laminated turbiditic sands, and 15% in

  16. Flow splitting modifies the helical motion in submarine channels

    NASA Astrophysics Data System (ADS)

    Islam, M. Ashraful; Imran, Jasim; Pirmez, Carlos; Cantelli, Alessandro

    2008-11-01

    Intricately meandering channels of various scales constitute a major morphological feature of the submarine slope and fan systems. These channels act as conduits of density-driven gravity underflows and in turn are shaped by these underflows. The relationship between channel curvature and the dynamics of sediment-laden underflows commonly known as turbidity current has been an enigma, and recently, a subject of controversy. This contribution unravels the flow field of turbidity current at submarine channel bends captured from large scale laboratory experiments. The experimental results show that a mildly sloping channel bank greatly enhances the tilt of the turbidity current-ambient water interface, so much so that the current completely separates from the convex or the inside bank. We also show that irrespective of the shape of the channel cross section, two cells of helical flow appear in confined submarine bend flow. The near-bed cell has a circulation pattern similar to that observed in fluvial channels; the other cell has an opposite sense of rotation. If, on the other hand, a portion of the flow detaches from the body of the current and spills to the concave or outside overbank area, the upper circulation cell becomes suppressed by the resulting lateral convection.

  17. Titan Submarine

    NASA Image and Video Library

    2015-06-15

    What would a submarine to explore the liquid methane seas of Saturn's Moon Titan look like? This video shows one submarine concept that would explore both the shoreline and the depths of this strange world that has methane rain, rivers and seas! The design was developed for the NASA Innovative Advanced Concepts (NIAC) Program, by NASA Glenn's COMPASS Team, and technologists and scientists from the Applied Physics Lab and submarine designers from the Applied Research Lab.

  18. Sublacustrine depositional fans in southwest Melas Chasma

    NASA Astrophysics Data System (ADS)

    Metz, Joannah M.; Grotzinger, John P.; Mohrig, David; Milliken, Ralph; Prather, Bradford; Pirmez, Carlos; McEwen, Alfred S.; Weitz, Catherine M.

    2009-10-01

    Two depositional fan complexes have been identified on the floor of southwest Melas Chasma. The western fan complex is located near the center of an enclosed basin in southwest Melas Chasma and is composed of multiple lobes with dendritic finger-like terminations. These fans are very flat and have a morphology unlike any other fan that has been previously identified on Mars. On the basis of the morphologic similarity of the western fan complex to the Mississippi submarine fan complex, we suggest that it may be a deep subaqueous fan depositional system. There are numerous channels on the surface of the western fan complex, and measurements of channel length, width, and sinuosity are consistent with channels observed on terrestrial submarine fans. The eastern Melas depositional fans are less well preserved and may be of deltaic or sublacustrine origin. Recognition of the fans supports earlier suggestions for the presence of a former lake in Melas Chasma and indicates that a significant body of water was present and stable at the surface of Mars for at least 102 to 104 years.

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

    NASA Astrophysics Data System (ADS)

    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

  20. Titan Submarines!

    NASA Astrophysics Data System (ADS)

    Oleson, S. R.; Lorenz, R. D.; Paul, M. V.; Hartwig, J. W.; Walsh, J. M.

    2017-02-01

    A NIAC Phase II submarine concept, dubbed 'Titan Turtle' for Saturn's moon Titan's northern sea, Ligea Mare. A design concept including science and operations is described for this -180°C liquid methane sea.

  1. Alluvial Fans

    NASA Image and Video Library

    2014-04-30

    Triangular shaped deposits at cliff edges are termed alluvial fans. Alluvial fans typically form in arid regions were water flow is limited, so deposits of material are not washed away as seen by NASA 2001 Mars Odyssey spacecraft.

  2. White submarine

    NASA Astrophysics Data System (ADS)

    While not everyone gets to live in a yellow submarine, the scientific community may get to have a decommissioned U.S. Navy nuclear submarine dedicated to it. The Sturgeon class of submarines, which scientists say are the ideal choice for the project, will be coming up for decommissioning in this next decade. So the time is ripe, scientists say. Two weeks ago, oceanographers, submarine specialists, marine biologists, and geophysicists, among others met at AGU headquarters in Washington to discuss how to get the project in the water. If all goes well, the project would be the "biggest thing that ever happened in ocean and Earth science," according to Lloyd Keigwin of the Woods Hole Oceanographic Institution, who convened the meeting. For example, the submarine could make many types of "compelling" research possible that can not be done now by other means, such as studies in the Arctic that may have significant bearing on global change research, Keigwin says. However, the imposing hurdles that the project must overcome are as big as the opportunities it offers. Foremost, there is a question as to who will pick up the tab for such an endeavor.

  3. Submarine landslides in Arctic sedimentation: Canada Basin

    USGS Publications Warehouse

    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.

  4. Submarine Landslides in Arctic Sedimentation: Canada Basin

    USGS Publications Warehouse

    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.

  5. Submarine atmospheres.

    PubMed

    Knight, D R; Tappan, D V; Bowman, J S; O'Neill, H J; Gordon, S M

    1989-12-01

    Nuclear submariners live and work in an atmosphere composed of approximately 80% naturally occurring nitrogen, 19% oxygen (manufactured aboard ship), and a complex mixture of inorganic and organic contaminants. The concentrations of contaminants exist as a balance between the rates of production from human and operational activities and the rate of removal by engineering systems. The biological effects of inorganic gases, particularly carbon dioxide, have been extensively studied. Investigators are now attempting to define the composition and concentration of volatile organic compounds that accumulate during 90-day submergences. Medical studies have not conclusively shown that crewmembers incur adverse health effects from continuous exposures to the sealed atmospheres of nuclear submarines.

  6. Contact Lenses on Submarines

    DTIC Science & Technology

    2014-09-26

    NAVAL SUBMARINE MEDICAL RESEARCH LABORATORY SUBMARINE BASE, GROTON, CONN. REPORT NUMBER 1048 CONTACT LENSES ON SUBMARINES... CONTACT LENSES ON SUBMARINES by James F. Socks, CDR, MSC, USN NAVAL SUBMARINE MEDICAL RESEARCH LABORATORY REPORT NUMBER 1048 NAVAL MEDICAL RESEARCH...DRSCHLAB Approved for public release; distribution unlimited SUMMARY PAGE PROBLEM To determine the feasibility of wearing contact lenses aboard

  7. Submarine landslides

    USGS Publications Warehouse

    Hampton, M.A.; Lee, H.J.; Locat, J.

    1996-01-01

    Landslides are common on inclined areas of the seafloor, particularly in environments where weak geologic materials such as rapidly deposited, finegrained sediment or fractured rock are subjected to strong environmental stresses such as earthquakes, large storm waves, and high internal pore pressures. Submarine landslides can involve huge amounts of material and can move great distances: slide volumes as large as 20,000 km3 and runout distances in excess of 140 km have been reported. They occur at locations where the downslope component of stress exceeds the resisting stress, causing movement along one or several concave to planar rupture surfaces. Some recent slides that originated nearshore and retrogressed back across the shoreline were conspicuous by their direct impact on human life and activities. Most known slides, however, occurred far from land in prehistoric time and were discovered by noting distinct to subtle characteristics, such as headwall scarps and displaced sediment or rock masses, on acoustic-reflection profiles and side-scan sonar images. Submarine landslides can be analyzed using the same mechanics principles as are used for occurrences on land. However, some loading mechanisms are unique, for example, storm waves, and some, such as earthquakes, can have greater impact. The potential for limited-deformation landslides to transform into sediment flows that can travel exceedingly long distances is related to the density of the slope-forming material and the amount of shear strength that is lost when the slope fails.

  8. Submarines against Submarines (Selected Articles),

    DTIC Science & Technology

    1979-07-05

    Denisov , A. D.; Kvitnitskiy, A. A.; Slepenkov, Z. F. 7_ 1 Chapter V COMBAT EMPLOYMENT OF SUBMARINES IN ANTISUBMARINE WARFARE IN THE VIEWS OF THE US...Geographic Names Transliteration System .... ii Foreword ....................................................... 1 Chapter V . Combat Employment of...Block Italic If * A a A, a P p p p ,’ 5 6 , b C B a V , v T T T m ra Yr 5y y y ,/7 #D, d qb €.: . E a Ye, ye; L, e* X x X x Kh, - 3i, m z h Ll 4 ’ y m

  9. Submarine Silicic Explosive Eruptions: what can submarine pyroclasts tell us?

    NASA Astrophysics Data System (ADS)

    Carey, R.; Allen, S.; McPhie, J.; Fiske, R. S.; Tani, K.

    2014-12-01

    Our understanding of submarine volcanism is in its infancy with respect to subaerial eruption processes. Two fundamental differences between eruptions in seawater compared to those on land are that (1) eruptions occur at higher confining pressures, and (2) in a seawater medium, which has a higher heat capacity, density and viscosity than air. Together with JAMSTEC collaborators we have a sample suite of submarine pumice deposits from modern volcanoes of known eruption depths. This sample suite spans a spectrum of eruption intensities, from 1) powerful explosive caldera-forming (Myojin Knoll caldera); to 2) weakly explosive cone building (pre-caldera Myojin Knoll pumice and Kurose-Nishi pumice); to 3) volatile-driven effusive dome spalling (Sumisu knoll A); to 4) passive dome effusion (Sumisu knoll B and C). This sample suite has exceptional potential, not simply because the samples have been taken from well-constrained, sources but because they have similar high silica contents, are unaltered and their phenocrysts contain melt inclusions. Microtextural quantitative analysis has revealed that (i) clast vesicularities remain high (69-90 vol.%) regardless of confining pressure, mass eruption rate or eruption style , (ii) vesicle number densities scale with inferred eruption rate, and (iii) darcian and inertial permeabilities of submarine effusive and explosive pyroclasts overlap with explosively-erupted subaerial pyroclasts.

  10. Assessment of ambulatory activity in the Republic of Korea Navy submarine crew.

    PubMed

    Choi, Seong-Woo; Lee, Jae-Ho; Jang, Young-Keun; Kim, Jung-Ryul

    2010-01-01

    A submarine crew in the Republic of the Korea Navy experienced significant physical inactivity during undersea deployment because of the narrow and confined space. Physical inactivity is known to be associated with a number of adverse health conditions in the long-term perspective. This study aimed to assess the ambulatory activity of submarine crew using pedometers. Study subjects (n=109) were the submarine crew from two diesel submarines and personnel from the Submarine Command. The subjects wore pedometers at their waistline and recorded their walking steps daily for a month. The submarine crew walked more than 7000 steps/day on average during the stationed period. However, the ambulatory activity of the submarine crew greatly declined to a level of around 2000 steps/day during deployment, which corresponded to the sedentary status category. Active exercise is recommended for the submarine crew to prevent potential adverse health outcomes related to the physical inactivity.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. New observations of sinuous channels on the Amazon Fan

    NASA Astrophysics Data System (ADS)

    Flood, R. D.

    2014-12-01

    High-sinuosity submarine fan channels on the Amazon Fan were first observed using long-range (GLORIA) side-scan sonar in 1982 and mapped in greater detail using multibeam sonar in 1984. These data have provided important insights into the nature and evolution of submarine channel systems. Subsequent studies on the Amazon Fan have focused on avulsion patterns, sedimentation patterns, fan growth and the climate record contained in fan sediments, and there has been relatively little additional work on the details of sinuous channel morphology. Channels on the Amazon Fan have been imaged by multibeam sonar on several occasions since 1984 during focused studies, regional mapping and ship transit. These multibeam data are being compiled and studied to better characterize these iconic channels. One observation of particular interest is that, on the Amazon Fan, channel-wall slumps appear to be more common than previously thought. Drilling of a cut-off meander during ODP Leg 155 on the Amazon Fan showed the presence of slumped material deeper in the channel suggesting that failure of the channel wall was in part responsible for the abandonment and filling of that meander loop. The failure also apparently created a sandy debris flow with clasts of fine-grained levee material transported in a sandy matrix. This sandy debris flow may have been able to flow along the channel and deposit at the seaward end where similar sediments can be found. Disturbed zones now visible on the inner walls of channels at several other places along the channels suggest that these kinds of inner-wall slumps may play important roles in channel evolution and fan growth. Channel-blocking slumps can isolate channel loops which can then fill with sandy sediments, and avulsions are likely if this kind of slump fills the channel. The failure of channel walls can also lead to new channel segments that tend to straighten the channel. Dramatic changes to the shape of the channel can likely lead to large and

  13. Submarine landslides: advances and challenges

    USGS Publications Warehouse

    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

  14. Late Pleistocene and Holocene depositional trends, processes, and history of Astoria deep-sea fan, Northeast Pacific

    USGS Publications Warehouse

    Nelson, H.

    1976-01-01

    The asymmetrical Astoria Fan (110 ?? 180 km) developed off the Columbia River and Astoria submarine canyon during the Pleistocene. Morphology, stratigraphy, and lithology have been outlined for a Pleistocene turbidite, and a Holocene hemipelagic sedimentary regime to generate geologically significant criteria for comparison with ancient equivalent deposits. Both gray silty clay of the Late Pleistocene and olive-gray clay of the Early Holocene are interrupted by turbidites. The few deeply incised fan valleys of the more steeply sloping upper fan contain thick, muddy and very poorly sorted sand and gravel beds that usually have poorly developed internal sedimentary structures. The numerous shallower fan valleys and distributaries of the flatter middle and lower fan contain thick, clean, and moderately sorted medium to fine sands that are vertically graded in texture, composition and well-developed internal sedimentary structures. Tuffaceous turbidites (containing Mazama ash, 6600 B.P.) can be traced as thick deposits (ca. 30-40 cm) throughout the Astoria Channel system and as thin correlative interbeds (ca. 1-2 cm) in interchannel areas. Similarly, sand/shale ratios are high throughout the fan valleys and the middle and lower fan areas of distributaries, but are low in the upper-fan interchannel areas. These depositional trends indicate that high-density turbidity currents carry coarse traction loads that remain confined in upper but not lower fan valleys. Fine debris selectively sorts out from channelized flows into overbank suspension flows that spread over the fan and deposit clayey silt. A high content of mica, plant fragments, and glass shards (if present) characterizes deposits of the overbank flows, a major process in the building of upper fan levees and interchannel areas. In the Late Pleistocene, turbidity currents funneled most coarse-grained debris through upper channels to depositional sites in middle and lower fan distributaries that periodically shifted

  15. Submarine cable route survey

    SciTech Connect

    Herrouin, G.; Scuiller, T.

    1995-12-31

    The growth of telecommunication market is very significant. From the beginning of the nineties, more and more the use of optical fiber submarine cables is privileged to that of satellites. These submarine telecommunication highways require accurate surveys in order to select the optimum route and determine the cable characteristics. Advanced technology tools used for these surveys are presented along with their implementation.

  16. Paint-Stirrer Submarine

    ERIC Educational Resources Information Center

    Young, Jocelyn; Hardy, Kevin

    2007-01-01

    In this article, the authors discuss a unique and challenging laboratory exercise called, the paint-stir-stick submarine, that keeps the students enthralled. The paint-stir-stick submarine fits beautifully with the National Science Education Standards Physical Science Content Standard B, and with the California state science standards for physical…

  17. Paint-Stirrer Submarine

    ERIC Educational Resources Information Center

    Young, Jocelyn; Hardy, Kevin

    2007-01-01

    In this article, the authors discuss a unique and challenging laboratory exercise called, the paint-stir-stick submarine, that keeps the students enthralled. The paint-stir-stick submarine fits beautifully with the National Science Education Standards Physical Science Content Standard B, and with the California state science standards for physical…

  18. Giant submarine canyons: is size any clue to their importance in the rock record?

    USGS Publications Warehouse

    Normark, William R.; Carlson, Paul R.

    2003-01-01

    Submarine canyons are the most important conduits for funneling sediment from continents to oceans. Submarine canyons, however, are zones of sediment bypassing, and little sediment accumulates in the canyon until it ceases to be an active conduit. To understand the potential importance in the rock record of any given submarine canyon, it is necessary to understand sediment-transport processes in, as well as knowledge of, deep-sea turbidite and related deposits that moved through the canyons. There is no straightforward correlation between the final volume of the sedimentary deposits and size o fthe associated submarine canyons. Comparison of selected modern submarine canyons together with their deposits emphasizes the wide range of scale differences between canyons and their impact on the rock record. Three of the largest submarine canyons in the world are incised into the Beringian (North American) margin of the Bering Sea. Zhemchug Canyon has the largest cross-section at the shelf break and greatest volume of incision of slope and shelf. The Bering Canyon, which is farther south in the Bering Sea, is first in length and total area. In contrast, the largest submarine fans-e.g., Bengal, Indus, and Amazon-have substantially smaller, delta-front submarine canyons that feed them; their submarine drainage areas are one-third to less than one-tenth the area of Bering Canyon. some very large deep-sea channells and tubidite deposits are not even associated with a significant submarine canyon; examples include Horizon Channel in the northeast Pacific and Laurentian Fan Valley in the North Atlantic. Available data suggest that the size of turbidity currents (as determined by volume of sediment transported to the basins) is also not a reliable indicator of submarine canyon size.

  19. Clast-contact conglomerates in submarine canyons: possible subaqueous sieve deposits

    SciTech Connect

    Fitzgerald, M.S.

    1987-05-01

    Thick, coarse, clast-contact conglomerates in submarine canyon fill have previously been attributed to rock-fall, grain-flow, or winnowing processes. However, these processes do not adequately explain some thick conglomeratic sequences. The proposed process of subaqueous sieve deposition could account for these clast-contact conglomerates. Subaerial sieve deposition has been documented on small-scale fan models and on alluvial fans. A subaerial sieve deposit begins as a debris flow which at some point freezes up. The matrix is then lost by subsequent filtration or outflow, and the emplacement of a clast-contact gravel ensues. A subaqueous sieve deposit would be slightly modified in that the matrix would not be lost by filtration into the submarine canyon floor, but rather by outflow at the terminus of the lobe immediately after deposition, or possibly from the top and/or sides of the freezing flow mass during transport. Besides forming in submarine canyons, subaqueous sieve deposits might also occur in paralic, submarine fan channel, and base-of-the-slope settings. In substantiating the existence of subaqueous sieve deposits, the sedimentary structures and grain-size data from recent sieve deposits on alluvial fans are compared to those of ancient submarine canyon deposits. Numerous similarities are found supporting this new method of deposition. Some discrepancies are encountered, but these are expected due to modifications caused by an aqueous medium.

  20. NASA ISS Portable Fan Assembly Acoustics

    NASA Technical Reports Server (NTRS)

    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.

  1. Controls on plan-form evolution of submarine channels

    NASA Astrophysics Data System (ADS)

    Imran, J.; Mohrig, D. C.

    2014-12-01

    Vertically aggrading sinuous channels constitute a basic building block of modern submarine fans and the greater continental slope. Interpretation of seismically imaged channels reveals a significant diversity in internal architecture, as well as important similarities and differences in the evolution of submarine channels relative to better studied rivers. Many submarine channel cross sections possess a 'gull wing' shape. Successive stacking of such channels demonstrates that systematic bank erosion is not required in order for lateral migration to occur. The lateral shift of such aggrading channels, however, is expected to be much less dynamic than in the case of terrestrial rivers. Recent high-resolution 3D seismic data from offshore Angola and an upstream segment of the Bengal Submarine Fan show intensely meandering channels that experience considerable lateral shifting during periods of active migration within submarine valleys. The cross sections of the actively migrating channels are similar to meandering river channels characterized by an outer cut-bank and inner-bank accretion. In submarine channels, the orientation of the secondary flow can be river-like or river-reverse depending on the channel gradient, cross sectional shape, and the adaptation length of the channel bend. In river channels, a single circulation cell commonly occupies the entire channel relief, redistributing the bed-load sediment across the channel, and influencing the thread of high velocity and thus the plan-form evolution of the channel. In submarine environments, the height of the circulation cell will be significantly smaller than channel relief, thus leading to development of lower relief point bars from bed-load transport. Nevertheless these "underfit" bars may play an important role in plan-form evolution of submarine channels. In rivers and submarine channels, the inclined surface accretion can be constructed via pure bed-load, suspended-load, or a combination of both transport

  2. Submarine neutrino communication

    NASA Astrophysics Data System (ADS)

    Huber, Patrick

    2010-09-01

    We discuss the possibility to use a high energy neutrino beam from a muon storage ring to provide one way communication with a submerged submarine. Neutrino interactions produce muons which can be detected either, directly when they pass through the submarine or by their emission of Cerenkov light in sea water, which, in turn, can be exploited with sensitive photo detectors. Due to the very high neutrino flux from a muon storage ring, it is sufficient to mount either detection system directly onto the hull of the submersible. The achievable data transfer rates compare favorable with existing technologies and do allow for a communication at the usual speed and depth of submarines.

  3. Fan-structure waves in shear ruptures

    NASA Astrophysics Data System (ADS)

    Tarasov, Boris

    2016-04-01

    This presentation introduces a recently identified shear rupture mechanism providing a paradoxical feature of hard rocks - the possibility of shear rupture propagation through the highly confined intact rock mass at shear stress levels significantly less than frictional strength. According to the fan-mechanism the shear rupture propagation is associated with consecutive creation of small slabs in the fracture tip which, due to rotation caused by shear displacement of the fracture interfaces, form a fan-structure representing the fracture head. The fan-head combines such unique features as: extremely low shear resistance (below the frictional strength), self-sustaining stress intensification in the rupture tip (providing easy formation of new slabs), and self-unbalancing conditions in the fan-head (making the failure process inevitably spontaneous and violent). An important feature of the fan-mechanism is the fact that for the initial formation of the fan-structure an enhanced local shear stress is required, however, after completion of the fan-structure it can propagate as a dynamic wave through intact rock mass at shear stresses below the frictional strength. Paradoxically low shear strength of pristine rocks provided by the fan-mechanism determines the correspondingly low transient strength of the lithosphere, which favours generation of new earthquake faults in the intact rock mass adjoining pre-existing faults in preference to frictional stick-slip instability along these faults. The new approach reveals an alternative role of pre-existing faults in earthquake activity: they represent local stress concentrates in pristine rock adjoining the fault where special conditions for the fan-mechanism nucleation are created, while further dynamic propagation of the new fault (earthquake) occurs at low field stresses even below the frictional strength.

  4. Gravity deposits in deep sea fans and on Continental Slopes, Black Sea

    SciTech Connect

    Ivanov, M.K.; Konyukhov, A.I.

    1988-08-01

    The Danube fan has a classical structure. It is clearly expressed in the bottom relief and traced by reflection profiles for more than 200 km. The fan body is levee valley, which splits in a mid-fan area into numerous meandering distributaries. The fan consists of gravity and hemipelagic deposits. These are mainly turbidites of various compositions. Channels are filled with grain-flow deposits (sand), debris-flow deposits (sandy clay with shells), and slides from valley walls (mud, sapropelic mud). Levees in upper and mid-fan areas are formed by specific turbidite sequences: mudstone crumbs in the base, thinly laminated silt and clays in the middle, blue mud on the top. Hemipelagic sediments increase noticeably on outer slopes of the levees. In the Pleistocene sequences these are mud; in the Holocene, sapropelic mud and coccolith-diatom ooze. Distal turbidites are widespread in the lower fan areas. In the base of each cycle is a thin sand-silt layer with unclear graded bedding; the upper part is represented by mud. Reflection profiles demonstrate an ancient fan system with buried channels and levees. Configurations of these bodies are very similar to those of the modern fans. The sedimentary lens on the sea floor opposite the mouths of submarine canyons of the Rioni, Inguri, Kodori, Supsa, and Chorokh Rivers was formed by overlapped modern and ancient fans. The Inguri and Rioni produced a practically single submarine fan, the largest in this area. It is rather well expressed morphologically and traced by reflection profiles for more than 100 km. In its lower part it overlays a number of small fans. The Rioni-Inguri fan is smaller than the Danube, but the whole system of overlapped fans occupies an area of about 17,000 km/sup 2/, being more than 3 km thick. The composition and structure of sediments in this deep-sea system change sharply, depending on the geomorphological position.

  5. Submarines, spacecraft and exhaled breath.

    PubMed

    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

  6. Monterey Fan: Growth pattern control by basin morphology and changing sea levels

    USGS Publications Warehouse

    Normark, W.R.; Gutmacher, C.E.; Chase, T.E.; Wilde, P.

    1984-01-01

    Monterey Fan is the largest modern fan off the California shore. Two main submarine canyon systems feed it via a complex pattern of fan valleys and channels. The northern Ascension Canyon system is relatively inactive during high sea-level periods. In contrast, Monterey Canyon and its tributaries to the south cut across the shelf and remain active during high sea level. Deposition on the upper fan is controlled primarily by the relative activity within these two canyon systems. Deposition over the rest of the fan is controlled by the oceanic crust topography, resulting in an irregular fan shape and periodic major shifts in the locus of deposition. ?? 1984 Springer-Verlag New York Inc.

  7. Controls on alluvial fan long-profiles

    USGS Publications Warehouse

    Stock, J.D.; Schmidt, K.M.; Miller, D.M.

    2008-01-01

    Water and debris flows exiting confined valleys have a tendency to deposit sediment on steep fans. On alluvial fans where water transport of gravel predominates, channel slopes tend to decrease downfan from ???0.10-0.04 to ???0.01 across wide ranges of climate and tectonism. Some have argued that this pattern reflects grain-size fining downfan such that higher threshold slopes are required just to entrain coarser particles in the waters of the upper fan, whereas lower slopes are required to entrain finer grains downfan (threshold hypothesis). An older hypothesis is that slope is adjusted to transport the supplied sediment load, which decreases downfan as deposition occurs (transport hypothesis). We have begun to test these hypotheses for alluvial fan long-profiles using detailed hydraulic and particle-size data in sediment transport models. On four alluvial fans in the western U.S., we find that channel hydraulic radiiare largely 0.5-0.9 m at fan heads, decreasing to 0.1-0.2 m at distal margins. We find that median gravel diameter does not change systematically along the upper 60%-80% of active fan channels as slope declines, so downstream gravel fining cannot explain most of the observed channel slope reduction. However, as slope declines, channel-bed sand cover increases systematically downfan from areal fractions of <20% above fan heads to distal fan values in excess of 70%. As a result, entrainment thresholds for bed material might decrease systematically downfan, leading to lower slopes. However, current models of this effect alone tend to underpredict downfan slope changes. This is likely due to off-channel gravel deposition. Calculations that match observed fan long-profiles require an exponential decline in gravel transport rate, so that on some fans approximately half of the load must be deposited off channel every -0.20-1.4 km downfan. This leads us to hypothesize that some alluvial fan long-proffies are statements about the rate of overbank deposition of

  8. Giant submarine landslides on the Colombian margin and tsunami risk in the Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Leslie, Stephen C.; Mann, Paul

    2016-09-01

    A series of three giant, previously unrecognized submarine landslides are defined on a 16,000 line km grid of multi-channel 2D seismic reflection profiles along the active margin of northern Colombia in the western Caribbean Sea. These deposits record the collapse and mobilization of immense segments (thousands of cubic kilometers) of the submarine slope and are comparable in scale to the largest known landslides on Earth. We show that the breakaway zone for these events corresponds to the tectonically over-steepened slopes of the Magdalena Fan, an extensive submarine fan composed of sediments sourced from the northern Andes and deposited by the Magdalena River. An over-pressured zone of weakness at the base of the gas-hydrate stability layer within the fan likely facilitates slope failure. Timing of these massive slope failures is constrained by well control and occurred from the mid-to-late Pliocene to mid-Pleistocene. To understand the tsunamigenic hazards posed by the recurrence of such an event today, we model the potential tsunami source created by a submarine landslide of comparable thickness (400 m) and lateral extent (1700 km2) derived from the over-steepened upper slopes of the present day Magdalena Fan. Our modeling indicates the recurrence of an analogous slope failure would result in a major tsunami that would impact population centers along the Caribbean coastlines of Colombia, Central America, and the Greater Antilles with little advance warning.

  9. Composite fan blade

    SciTech Connect

    Farr, J.D.

    1993-08-31

    A composite fan blade is described for a prop fan engine comprising: a support disk having a plurality of hinge lugs formed therein, the disk being connected to an engine drive means; a bushing element; a fan blade formed from a first set of radially oriented unidirectional layers of fibers, the first set of layers of fibers being wrapped around the bushing element to form an elongated front side, an elongated back side, and a portion encompassing the bushing element; a blade platform formed from a second set of unidirectional layers of fibers having a first and a second end which are both wrapped around respective resin filler elements to form resin filled support pockets, the second set of unidirectional layers of fibers being wrapped around the portion of the fan blade encompassing the bushing element to place the resin filled support pockets against the portion of the fan blade encompassing the bushing element, wherein the fan blade and the blade platform form a fan blade assembly, the fan blade assembly having a plurality of hinge slots formed therein; and a pin element extending through the hinge formed by the plurality of hinge lugs in the support disk and the plurality of hinge slots in the fan blade assembly for attaching the fan blade assembly to the support disk.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    Gasier, Heath G.; Young, Colin R.; Gaffney-Stomberg, Erin; McAdams, Douglas C.; Lutz, Laura J.; McClung, James P.

    2016-01-01

    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. PMID:26867201

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

    USGS Publications Warehouse

    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 < 1:1000, or 0??0.5???), (< 10 fathoms, or 18 m relief). 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

  13. Autogenic limits on allogenic controls of submarine landform evolution

    NASA Astrophysics Data System (ADS)

    Dorrell, R. M.; McCaffrey, W. D.; Burns, A. D.

    2014-12-01

    Seafloor channel avulsion events recorded in the stratigraphic architecture of submarine fans are often identified as signals of boundary change of the associated sediment supply system. However, interpretation of such signals that are persevered in the rock record is complicated by the interplay between internal (autogenic) forcing and external (allogenic) forcing on the system which may have caused the avulsion of the channel. To investigate the importance of autogenic forcing on seafloor channel evolution, novel models have been constructed which calculate the width-averaged growth of a channel levee system with progressive deposition. These models demonstrate that seafloor channel-levee systems are inherently unstable and will avulse purely subject to autogenic forcing. It is demonstrated that this instability arises as a function of geometric constraints on the cross-sectional shape of the evolving channel and its bounding levees under aggradational flow conditions. Analytical solutions to these simplified models demonstrate that change in the area of the channel is given by the comparative rate at which the bounding outer levee and channel are built up. Whilst the outer levee is built up faster than the channel, there is a relative increase in channel size - increasing the degree by which a flow is confined and thus the decreasing the likelihood of an avulsion. However, if the channel is built up faster than the outer levee the degree by which the flow is confined by the channel will decrease, and thus the likelihood of avulsion will increase. It is seen that as bounding levees become large, and thus cannot be built up as fast as the channel, the evolution of the channel is inherently limited. However, autogenic channel-levee instability likely arises over very long time periods, with the half-life of channel decay proportional to the channel-levee system size. Thus, it is expected that additional external (allogenic) forcing, such as boundary condition

  14. The submarine service of the future?

    PubMed

    Bland, S A

    2000-01-01

    Space missions, although now routine, are unique in terms of their environment and logistical requirements. The number of missions (man-hours) remains relatively small and planning still relies on comparisons with analogous missions, including submarine operations. Antarctic missions, which tend not to be classified, have provided more information about isolated communities because of the number of personnel per base. Space medicine has traditionally been an extension of aviation medicine with high g-forces involved in the transition from Earth to orbit and astronauts such as Neil Armstrong recruited from the test pilot fraternity. As the length of a mission increases and the space habitation relies more on regenerative systems, the environment becomes more analogous with today's nuclear submarines. As well as the air purification implications, radiation still is a significant hazard with even greater impact on future Mars missions requiring the provision of health physics monitoring, advice and countermeasures well established in the submarine flotilla. Nevertheless, the specialty space medicine will progress as a specialty in its own right, pooling expertise from other specialties such as aviation, radiation, emergency and occupational medicine taking human exploration beyond the confines of land and sea.

  15. Distribution and tsunamigenic potential of submarine landslides in the Gulf of Mexico

    USGS Publications Warehouse

    Chaytor, Jason D.; Twichell, David C.; Lynett, Patrick; Geist, Eric L.

    2010-01-01

    The Gulf of Mexico (GOM) is a geologically diverse ocean basin that includes three distinct geologic provinces: a carbonate province, a salt province, and canyon to deep-sea fan province, all of which contain evidence of submarine mass movements. The threat of submarine landslides in the GOM as a generator of near-field damaging tsunamis has not been widely addressed. Submarine landslides in the GOM are considered a potential tsunami hazard because: (1) some dated landslides in the GOM have post-glacial ages and (2) recent seismicity recorded within the GOM. We present a brief review of the distribution and style of submarine landslides that have occurred in the GOM during the Quaternary, followed by preliminary hydrodynamic modeling results of tsunami generation from the East Breaks landslide off Corpus Christie, TX.

  16. 1. EXTERIOR VIEW OF NEW FAN HOUSE AND HILLMAN FAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR VIEW OF NEW FAN HOUSE AND HILLMAN FAN HOUSE LOOKING NORTHWEST The building on the left, the New Fan House, houses a Corliss steam engine which powered a Buffalo Forge Company single inlet Duplex Conoidal centrifugal exhausted fan through a metal updraft chimney. Part of the brick airway leading to the Baltimore shaft is visible to its right rear. The Hillman Fan House, on the right, houses the 1883 double inlet Guibal fan. The south entry, the curve of the fan housing, and brick updraft chimney are visible in this view. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  17. Making a Submarine.

    ERIC Educational Resources Information Center

    Cornacchia, Deborah J.

    2002-01-01

    Describes Archimedes principle and why a ship sinks when it gets a hole in it. Suggests an activity for teaching the concept of density and water displacement through the construction of a simple submarine. Includes materials and procedures for this activity. (KHR)

  18. Making a Submarine.

    ERIC Educational Resources Information Center

    Cornacchia, Deborah J.

    2002-01-01

    Describes Archimedes principle and why a ship sinks when it gets a hole in it. Suggests an activity for teaching the concept of density and water displacement through the construction of a simple submarine. Includes materials and procedures for this activity. (KHR)

  19. Industrial Turbine Fans

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Westinghouse Corp. & R &D Center's development of blades of an advanced controllable-pitch axial fan used in electrical power generation was aided by four computer programs supplied by COSMIC. Programs helped determine sensitivity of large industrial turbines and fans to particular matter such as dust and ash which can cause erosion. Programs also helped substantially reduce developmental costs.

  20. Volume balance of a submarine landslide in the Espírito Santo Basin, offshore Brazil: Quantifying seafloor erosion, sediment accumulation and depletion

    NASA Astrophysics Data System (ADS)

    Alves, Tiago M.; Cartwright, Joseph A.

    2009-11-01

    Degrees of seafloor erosion, sediment accumulation and depletion are quantified using a 3D seismic volume of a small submarine landslide offshore Brazil. In the study area, the upper boundaries of large remnant blocks — kept in situ during the main instability event — and the interpreted non-failed margins of the landslide comprise a reliable estimate for the position of the seafloor at the time the submarine landslide was generated. Remnant blocks of strata show little internal deformation, particularly at their base, and were kept upright during a principal instability event triggered in response to regional halokinesis and associated overburden faulting. They are laterally bounded by a mixed succession of mass-wasted chaotic strata, rafted blocks and post-slide sub-horizontal units. Despite the thin accumulation of failed strata now visible, the interpreted data indicate that submarine landslides of small areal dimensions can erode substantial volumes of seafloor sediment. Consequently, the more than 300 m of eroded seafloor strata offshore Brazil is of a similar scale to the largest failures recorded on continental margins (e.g. Storegga Slide; Amazon Fan complex; Cape Fear slide). The scale relationships presented in this paper indicate that the magnitude of seafloor erosion experienced during instability events may not be recorded by distal mass-wasted strata, which can be demonstrably thinner than the original volume of failed sediment. Thus, we conclude that the relative expression of accumulated slide strata is not directly related to the original volume of failed material. In addition, small-scale landslides can be responsible for the erosion of thick seafloor deposits, a factor that can potentially cause significant losses of seal capacity in overburden successions due to the sudden release of confining pressures in a vertical direction.

  1. Superelevation and overspill control secondary flow dynamics in submarine channels

    NASA Astrophysics Data System (ADS)

    Dorrell, R. M.; Darby, S. E.; Peakall, J.; Sumner, E. J.; Parsons, D. R.; Wynn, R. B.

    2013-08-01

    In subaerial and submarine meander bends, fluid flow travels downstream in a helical spiral, the structure of which is determined by centrifugal, hydrostatic, baroclinic, and Coriolis forces that together balance frictional stresses generated by the flow. The sense of rotation of this helical flow, and in particular, whether the near bed flow is directed toward the inner bank, e.g., "river-normal," or outer bank, e.g., "river-reversed," is crucial to the morphodynamic evolution of the channel. However, in recent years, there has been a debate over the river-normal or river-reversed nature of submarine flows. Herein, we develop a novel three-dimensional closure of secondary flow dynamics, incorporating downstream convective material transport, to cast new light on this debate. Specifically, we show that the presence of net radial material transport, arising from flow superelevation and overspill, exerts a key control on the near bed orientation of secondary flow in submarine meanders. Our analysis implies that river-reversed flows are likely to be much more prevalent throughout submarine-canyon fan systems than prior studies have indicated.

  2. Arctic Submarine Slope Stability

    NASA Astrophysics Data System (ADS)

    Winkelmann, D.; Geissler, W.

    2010-12-01

    Submarine landsliding represents aside submarine earthquakes major natural hazard to coastal and sea-floor infrastructure as well as to coastal communities due to their ability to generate large-scale tsunamis with their socio-economic consequences. The investigation of submarine landslides, their conditions and trigger mechanisms, recurrence rates and potential impact remains an important task for the evaluation of risks in coastal management and offshore industrial activities. In the light of a changing globe with warming oceans and rising sea-level accompanied by increasing human population along coasts and enhanced near- and offshore activities, slope stability issues gain more importance than ever before. The Arctic exhibits the most rapid and drastic changes and is predicted to change even faster. Aside rising air temperatures, enhanced inflow of less cooled Atlantic water into the Arctic Ocean reduces sea-ice cover and warms the surroundings. Slope stability is challenged considering large areas of permafrost and hydrates. The Hinlopen/Yermak Megaslide (HYM) north of Svalbard is the first and so far only reported large-scale submarine landslide in the Arctic Ocean. The HYM exhibits the highest headwalls that have been found on siliciclastic margins. With more than 10.000 square kilometer areal extent and app. 2.400 cubic kilometer of involved sedimentary material, it is one of the largest exposed submarine slides worldwide. Geometry and age put this slide in a special position in discussing submarine slope stability on glaciated continental margins. The HYM occurred 30 ka ago, when the global sea-level dropped by app. 50 m within less than one millennium due to rapid onset of global glaciation. It probably caused a tsunami with circum-Arctic impact and wave heights exceeding 130 meters. The HYM affected the slope stability field in its neighbourhood by removal of support. Post-megaslide slope instability as expressed in creeping and smaller-scaled slides are

  3. Active submarine volcano sampled

    USGS Publications Warehouse

    Taylor, B.

    1983-01-01

    On June 4, 1982, two full dredge hauls of fresh lava were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, in the western Pacific Ocean, from the water depths of 1,200 and 2,700 feet. the shallower dredge site was within 0.5 mile of the active submarine vent shown at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano that has been observed to erupt every year or two for at least the last 30 years (see photographs). An island formed in 1952, 1961, 1965, and 1978; but, in each case, it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982. 

  4. ANS Based Submarine Simulation

    DTIC Science & Technology

    1994-08-01

    computer based simulation proraon supplied by Dr. John Ware at Computer Sceinces Corporation (CSC). Thee am two reasons to use simulated data instead...ANS (Artificial Neural System) capable of modeling submarine perfomncie based on full scale data generated using a computer based simulabon program...The Optimized Entropy algorilth enables the solutions to diffcu problems on a desktop computer within an acceptable time frame. Ob6ectve for w

  5. Online Fan Practices and CALL

    ERIC Educational Resources Information Center

    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…

  6. Alluvial fan in China

    NASA Image and Video Library

    2008-09-05

    This image captures the beauty of a major alluvial fan in Tsinghai, a province located in Northwestern China. This archival image was taken from NASA Space Shuttle in 1997 as part of its ISS EarthKAM mission.

  7. Architectural elements of fan-delta complex in Pennsylvanian Taos Trough, New Mexico

    SciTech Connect

    Soegaard, K.

    1989-03-01

    Identification of architectural elements within alluvial-fan and subaqueous fan-delta gravel units is fundamental to resolving depositional processes within fan-delta complexes of the Pennsylvanian Taos trough, New Mexico. Subaqueous fan-delta deposits consist of lenticular gravel-body complexes encased by black, basinal shales. Gravel-body complexes are composed of a series of stacked gravel lenses, each of which is enveloped by fifth-order bounding surfaces. The central portion of individual gravel lenses contains a channel complex. Channels are outlined by third- and fourth-order bounding surfaces and are infilled by high-density gravity flow deposits. The fringe of submarine gravel lenses consists of stacked, laterally continuous Bouma sequences separated by second-order bounding surfaces. Bouma sequences were deposited by dilute turbidity flows during evacuation of submarine channels. Subaqueous channel complexes within gravel lenses represent midfan channels, whereas the fringe of lenticular gravel lenses represent outer-fan lobes. Recognition of depositional processes and architectural elements of fan deltas in the Sandia Formation enables distinction between these and other types of coarse-grained deltas in the Taos trough. This, in turn, has implications for resolving evolution of the trough.

  8. Supercritical Submarine Channel Morphodynamics from Integrated Investigation of the Western North American Continental Margin

    NASA Astrophysics Data System (ADS)

    Covault, J. A.; Fildani, A.; Hubbard, S. M.; Hughes Clarke, J. E.; Kostic, S.; Paull, C. K.; Sylvester, Z.

    2015-12-01

    Submarine channels are conduits through which turbidity currents and related mass movements transport sediment into the deep sea, thereby playing important roles in the development of continental margins and biogeochemical cycles. To gain a better understanding of submarine channel morphodynamic evolution we explore a variety of channel systems from the western North American continental margin with varying sinuosity and levee geometry, terraces, channel cut-offs, and sediment waves in incipient channels, along thalwegs of well-developed channels, and on levees. Repeat bathymetric surveys of submarine channels in fjords of British Columbia and the Monterey canyon underscore the transience of fine-scale detail in channelized geomorphology, and multi-phase bed reworking, local deposition, and bypass of turbidity currents. Numerical modeling is combined with interpretations of channel geomorphology and strata in the Monterey and San Mateo canyon-channel systems to demonstrate that some of the sediment waves are likely to be cyclic steps. Submarine cyclic steps are long-wave, upstream-migrating bedforms in which each bedform in the series is bounded by a hydraulic jump in an overriding turbidity current, which is Froude-supercritical over the lee side of the bedform and Froude-subcritical over the stoss side. Submarine turbidity currents are susceptible to supercritical flow because of the reduced gravitational acceleration of dilute suspensions. Higher submarine slopes common to the North American continental margin also promote supercritical flow, which might not be as common across lower slopes of large passive margins such as the Amazon, Indus, and Bengal submarine fans. We posit that cyclic steps are a common morphodynamic expression in many continental margins. Continued integration of high-resolution data, such as repeat geophysical surveys, acoustic doppler current profiler measurements, and turbidite outcrops, which provide insights into the longer

  9. Seismic stratigraphic comparison of DSDP Leg 96 results with older Mississippi fan lobes, Gulf of Mexico

    SciTech Connect

    Weimer, P.; Buffler, R.T.

    1987-05-01

    DSDP Leg 96 drilled the youngest depositional lobe of the Mississippi fan at nine sites. These sites were designed to provide a set of reference cores to help explain the development of Quaternary and older submarine fans. The youngest fan lobe is dominated by a single, sinuous aggradational channel system, characterized by high-amplitude reflections that represent channel-lag gravels and sands, while adjacent laterally continuous reflections correspond to fine-grained overbank sediments. Analysis of 12,000 km of multifold seismic data from the Mississippi fan provides a method for comparing the drilling results with the seismic stratigraphy of the nine older Mississippi fan lobes. Sinuous channels and associated facies are present in all older lobes in the middle fan area, although there is a greater diversity in channel/overbank distribution and interpreted depositional processes. For example, four of the lobes have several coeval channels that are fed by separate submarine canyons in the slope, and a bifurcating channel pattern caused by channel avulsion is present in six different lobes along the middle and lower fan. In addition, an important seismic facies consisting of mounded, hummocky, and chaotic reflections is present at the base of six older lobes. This facies is more areally restricted than the overlying, well-developed channel/overbank deposits and is interpreted to represent coarse-grained channel sediments deposited during lowering sea level. Although Leg 96 drilling provides sedimentologic information that can be used for comparison with other fans, this seismic stratigraphic study of the entire Mississippi fan suggests that additional processes were operating that were not explained by the drilling results.

  10. Submarine Landslides: A Multidisciplinary Crossroad

    NASA Astrophysics Data System (ADS)

    Moscardelli, L. G.

    2014-12-01

    The study of submarine landslides has advanced considerably in the last decade. A multitude of geoscience disciplines, including marine, petroleum and planetary geology, as well as geohazard assessments, are concerned with the study of these units. Oftentimes, researchers working in these fields disseminate their findings within their own communities and a multidisciplinary approach seems to lack. This presentation showcases several case studies in which a broader approach has increased our understanding of submarine landslides in a variety of geologic settings. Three-dimensional seismic data from several continental margins (Trinidad, Brazil, Morocco, Canada, GOM), as well as data from outcrop localities are shown to explore geomorphological complexities associated with submarine landslides. Discussion associated with the characterization and classification of submarine landslides is also part of this work. Topics that will be cover include: 1) how data from conventional oil and gas exploration activities can be used to increase our understanding of the dynamic behavior of submarine landslides, 2) analogies between terrestrial submarine landslides and potential Martian counterparts, 3) impact of submarine landslides in margin construction, as well as their economic significance and 4) the importance of quantifying the morphology of submarine landslides in a systematic fashion.

  11. Anti Submarine Warfare Search Models

    DTIC Science & Technology

    2016-09-01

    DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words) Stealth and high endurance make submarines ideally suited to a variety of missions, and finding...INTENTIONALLY LEFT BLANK v ABSTRACT Stealth and high endurance make submarines ideally suited to a variety of missions, and finding ways to detect, track...II. UNIFORM DIRECTION ......................................................................................5 A. NOTATION AND DEFINITIONS

  12. Current submarine atmosphere control technology.

    PubMed

    Mazurek, W

    1998-01-01

    Air purification in submarines was introduced towards the end of World War II and was limited to the use of soda lime for the removal of carbon dioxide and oxygen candles for the regeneration of oxygen. The next major advances came with the advent of nuclear-powered submarines. These included the development of regenerative and, sometimes, energy-intensive processes for comprehensive atmosphere revitalization. With the present development of conventional submarines using air-independent propulsion there is a requirement for air purification similar to that of the nuclear-powered submarines but it is constrained by limited power and space. Some progress has been made in the development of new technology and the adoption of air purification equipment used in the nuclear-powered submarines for this application.

  13. Fan Noise Test Facility

    NASA Image and Video Library

    1969-01-21

    The Fan Noise Test Facility built at the Lewis Research Center to obtain far-field noise data for the National Aeronautics and Space Administration (NASA) and General Electric Quiet Engine Program. The engine incorporated existing noise reduction methods into an engine of similar power to those that propelled the Boeing 707 or McDonnell-Douglas DC-8 airliner. The new the low-bypass ratio turbofan engines of the 1960s were inherently quieter than their turbojet counterparts, researchers had a better grasp of the noise generation problem, and new acoustic technologies had emerged. Lewis contracted General Electric in 1969 to build and aerodynamically test three experimental engines with 72-inch diameter fans. The engines were then brought to Lewis and tested with an acoustically treated nacelle. This Fan Noise Test Facility was built off of the 10- by 10-Foot Supersonic Wind Tunnel’s Main Compressor and Drive Building. Lewis researchers were able to isolate the fan’s noise during these initial tests by removing the core of the engine. The Lewis test rig drove engines to takeoff tip speeds of 1160 feet per second. The facility was later used to test a series of full-scale model fans and fan noise suppressors to be used with the quiet engine. NASA researchers predicted low-speed single-stage fans without inlet guide vanes and with large spacing between rotors and stators would be quieter. General Electric modified a TF39 turbofan engine by removing the the outer protion of the fan and spacing the blade rows of the inner portion. The tests revealed that the untreated version of the engine generated less noise than was anticipated, and the acoustically treated nacelle substantially reduced engine noise.

  14. Flushing submarine canyons.

    PubMed

    Canals, Miquel; Puig, Pere; de Madron, Xavier Durrieu; Heussner, Serge; Palanques, Albert; Fabres, Joan

    2006-11-16

    The continental slope is a steep, narrow fringe separating the coastal zone from the deep ocean. During low sea-level stands, slides and dense, sediment-laden flows erode the outer continental shelf and the continental slope, leading to the formation of submarine canyons that funnel large volumes of sediment and organic matter from shallow regions to the deep ocean(1). During high sea-level stands, such as at present, these canyons still experience occasional sediment gravity flows(2-5), which are usually thought to be triggered by sediment failure or river flooding. Here we present observations from a submarine canyon on the Gulf of Lions margin, in the northwest Mediterranean Sea, that demonstrate that these flows can also be triggered by dense shelf water cascading (DSWC)-a type of current that is driven solely by seawater density contrast. Our results show that DSWC can transport large amounts of water and sediment, reshape submarine canyon floors and rapidly affect the deep-sea environment. This cascading is seasonal, resulting from the formation of dense water by cooling and/or evaporation, and occurs on both high- and low-latitude continental margins(6-8). DSWC may therefore transport large amounts of sediment and organic matter to the deep ocean. Furthermore, changes in the frequency and intensity of DSWC driven by future climate change may have a significant impact on the supply of organic matter to deep-sea ecosystems and on the amount of carbon stored on continental margins and in ocean basins.

  15. 30 CFR 57.4504 - Fan installations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Control Installation/construction/maintenance § 57.4504 Fan installations. (a) Fan houses, fan bulkheads... of combustible materials, except installed wiring, ground and track support, headframes, and...

  16. 30 CFR 57.4504 - Fan installations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Control Installation/construction/maintenance § 57.4504 Fan installations. (a) Fan houses, fan bulkheads... of combustible materials, except installed wiring, ground and track support, headframes, and...

  17. 30 CFR 57.4504 - Fan installations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Control Installation/construction/maintenance § 57.4504 Fan installations. (a) Fan houses, fan bulkheads... of combustible materials, except installed wiring, ground and track support, headframes, and...

  18. 30 CFR 57.4504 - Fan installations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Control Installation/construction/maintenance § 57.4504 Fan installations. (a) Fan houses, fan bulkheads... of combustible materials, except installed wiring, ground and track support, headframes, and...

  19. 30 CFR 57.4504 - Fan installations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Control Installation/construction/maintenance § 57.4504 Fan installations. (a) Fan houses, fan bulkheads... of combustible materials, except installed wiring, ground and track support, headframes, and...

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Smart Fan Modules And System

    DOEpatents

    Cipolla, Thomas M.; Kaufman, Richard I.; Mok, Lawrence S.

    2003-07-15

    A fan module including: two or more individual fans, each fan having an air movement means and a motor engaged with the air movement means for accelerating air entering each of the two or more individual fans; a temperature sensor for sensing a temperature associated with the two or more fans and for outputting a first signal corresponding to the temperature; rotational speed sensor for outputting a second signal corresponding to a rotational speed of each of the two or more fans; and a processor for receiving the first and second signals and controlling the two or more individual fans based on the first and second signals. A fan module including: two or more individual fans, each fan having an air movement means and a motor engaged with the air movement means for accelerating air entering each of the two or more individual fans; a temperature sensor for sensing a temperature associated with the two or more fans and for outputting a first signal corresponding to the temperature; rotational speed sensor for outputting a second signal corresponding to a rotational speed of each of the two or more fans; and a processor for receiving the first and second signals and controlling the two or more individual fans based on the first and second signals.

  2. Submarine laser communications

    NASA Astrophysics Data System (ADS)

    McConathy, D. R.

    The Department of the Navy and the Defense Advanced Research Projects Agency (DARPA) are sponsoring a joint study to investigate the use of blue-green laser technology to comunicate with submarines at operating depths. Two approaches are under investigation - one in which the laser itself is space-based, and the other in which the laser is ground-based with its beam redirected to the earth's surface by an orbiting mirror. This paper discusses these two approaches, and presents a brief history of activities which led to the current studies.

  3. Preliminary Aerodynamic Investigation of Fan Rotor Blade Morphing

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    2012-01-01

    Various new technologies currently under development may enable controlled blade shape variability, or so-called blade morphing, to be practically employed in aircraft engine fans and compressors in the foreseeable future. The current study is a relatively brief, preliminary computational fluid dynamics investigation aimed at partially demonstrating and quantifying the aerodynamic potential of fan rotor blade morphing. The investigation is intended to provide information useful for near-term planning, as well as aerodynamic solution data sets that can be subsequently analyzed using advanced acoustic diagnostic tools, for the purpose of making fan noise comparisons. Two existing fan system models serve as baselines for the investigation: the Advanced Ducted Propulsor fan with a design tip speed of 806 ft/sec and a pressure ratio of 1.294, and the Source Diagnostic Test fan with a design tip speed of 1215 ft/sec and a pressure ratio of 1.470. Both are 22-in. sub-scale, low-noise research fan/nacelle models that have undergone extensive experimental testing in the 9- by 15-foot Low Speed Wind Tunnel at the NASA Glenn Research Center. The study, restricted to fan rotor blade morphing only, involves a fairly simple blade morphing technique. Specifically, spanwise-linear variations in rotor blade-section setting angle are applied to alter the blade shape; that is, the blade is linearly retwisted from hub to tip. Aerodynamic performance comparisons are made between morphed-blade and corresponding baseline configurations on the basis of equal fan system thrust, where rotor rotational speed for the morphed-blade fan is varied to change the thrust level for that configuration. The results of the investigation confirm that rotor blade morphing could be a useful technology, with the potential to enable significant improvements in fan aerodynamic performance. Even though the study is very limited in scope and confined to simple geometric perturbations of two existing fan

  4. 9. DETAIL OF THE FAN HOUSE INTERIOR, SHOWING FAN OPENINGS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. DETAIL OF THE FAN HOUSE INTERIOR, SHOWING FAN OPENINGS. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

  5. Are the dimensions of submarine lobe systems independent of allogenic factors?

    NASA Astrophysics Data System (ADS)

    Prélat, A.; Covault, J. A.; Hodgson, D. M.; Fildani, A.; Flint, S. S.

    2010-05-01

    Submarine lobe dimensions from six different systems are compared: 1) the exhumed Permian Fan 3 lobe complex of the Tanqua Karoo, South Africa; 2) the modern Amazon fan channel-mouth lobe complex, offshore Brazil; 3) a portion of the modern distal Zaïre fan, offshore Angola / Congo; 4) a Pleistocene fan of the Kutai Basin, subsurface offshore Indonesia; 5) the modern Golo system, offshore east Corsica, France; and 6) a lobe complex deposited in the shallow subsurface, offshore Nigeria. These six systems have significantly different source-to-sink configurations (shelf dimension and slope topography), sediment supply characteristics (calibre and rate), tectonic settings, (palaeo) latitude, and delivery systems. Despite these differences, the lobe deposits share similar geometric and dimensional characteristics. Lobes are grouped into two distinct populations of geometries that can be related to basin-floor topography. The first population corresponds to areally extensive but thin lobes (average width 14 km × length 35 km × thickness 12 m) that were deposited onto low relief basin floor areas, like the Tanqua Karoo, the Amazon and the Zaïre systems. The second population corresponds to areally smaller but thicker lobes (average width 5 km × length 8 km × thickness 30 m) that were deposited into settings with higher amplitude of relief, like in the Corsican trough, the Kutai basin, and offshore Nigeria. Basin floor topography confining the lobes can be very subtle, and only occur on one side of the system. The two populations of lobe types, however, share similar volumes, in the order of 1 or 2 km3. The largest lobes are observed in the Zaïre fan, where the average lobe volume reaches 3.3 km3 and the smallest lobes are observed in the Corsican trough where the average lobe volume is 0.4 km3. This variation in lobe volume is minor when compared to the variation observed in present-day up-dip drainage systems, which provide sediment to the deep-water depositional

  6. Prediction of ducted fan performance

    NASA Technical Reports Server (NTRS)

    Mendenhall, M. R.; Spangler, S. B.

    1972-01-01

    Computer program to predict performance of ducted fan combination at specified advance ratio and angle of attack is described. Parameters affecting performance of ducted fan are presented. Information obtained from computer program is explained for various conditions considered.

  7. Advanced Noise Control Fan (ANCF)

    NASA Image and Video Library

    2014-01-15

    The Advanced Noise Control Fan shown here is located in NASA Glenn’s Aero-Acoustic Propulsion Laboratory. The 4-foot diameter fan is used to evaluate innovate aircraft engine noise reduction concepts less expensively and more quickly.

  8. Alluvial Fans in Mojave Crater

    NASA Image and Video Library

    2015-05-20

    This image from NASA Mars Reconnaissance Orbiter shows a landscape that is pervasively eroded, right up to the tops of the ridges, with channels extending down into depositional fans much like alluvial fans in the Mojave Desert.

  9. Controls on alluvial fan morphology

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

    Using laboratory experiments, we investigate the influence of water and sediment discharges on the morphology of an alluvial fan. In our flume, a single-thread river deposits corundum sand (0.3 mm) into a conical fan. We record the fan progradation with top-view images, and measure its shape using the deformation of a Moiré pattern. The fan remains virtually self-affine as it grows, with a nearly constant slope. We find that, when the sediment discharge is small, the longitudinal slope of the fan remains close to that of a river at the threshold for sediment transport. A higher sediment discharge causes the fan's slope to depart from the threshold value. Due to the downstream decrease of the sediment load, this slope gets shallower towards the fan's toe. This suggests that the proximal slope of an alluvial fan could be a proxy for the sediment flux that feeds it.

  10. Analytical Lift Fan Noise Study

    NASA Technical Reports Server (NTRS)

    Rao, G. V. R.; Chu, W. T.; Digumarthi, R. V.

    1973-01-01

    Based on reasonable estimates of flow conditions occurring in an axial fan, acoustic radiation from various noise sources is evaluated. Results of computations on two specific fans are presented, and relative significance of the various sources is examined.

  11. Cyclic sediment deposition within Amazon deep-sea fan

    SciTech Connect

    Manley, P.L.; Flood, R.D.

    1988-08-01

    The Upper and middle Amazon Fan has grown in a cyclic fashion. An individual deposition cycle consists of (1) a widespread basal, acoustically transparent seismic unit (interpreted as debris-flow deposits) that fills and levels preexisting topographic lows, and (2) a levee complex built of overlapping channel-levee systems. Two and possibly three cycles have been identified within the Amazon Fan. The levee complex beneath one debris flow originated from a different submarine canyon than did the levee complex above the debris flow, suggesting that these levee complexes formed during different sea level lowstands. Calculations based on present sediment discharge of the Amazon River suggest that an entire levee complex can form within the time span of a single glacial stage, such as the Wisconsin; however, the levee complex probably could not have formed during the relatively short time interval when sea level rose rapidly at the end of a glacial stage. The basal seismic units (debris-flow deposits) may have been deposited at any time during sea level fluctuations. Although seismic evidence suggests that this cyclic sedimentation pattern may be related to glacio-eustatic sea level variations, cyclic fan growth may be attributed to other processes as well. For example, a bottom-simulating reflector (BSR) observed within the upper fan appears to be a gas hydrate. Migration of the hydrate phase boundary during sea level fluctuations and diapiric activity may be mechanisms for initiating widespread debris flows. 10 figs.

  12. Submarine Volcanic Eruptions and Potential Analogs for Venus

    NASA Technical Reports Server (NTRS)

    Wilson, L.; Mouginismark, P. J.; Fryer, P.; Gaddis, L. R.

    1985-01-01

    As part of an analysis program to better understand the diversity of volcanic processes on the terrestrial planets, an investigation of the volcanic landforms which exist on the Earth's ocean floor was initiated. In part, this analysis is focused toward gaining a better understanding of submarine volcanic landforms in their own right, but also it is hoped that these features may show similarities to volcanic landforms on Venus, due to the high ambient water (Earth) and atmospheric (Venus) pressures. A series of numerical modelling experiments was performed to investigate the relative importance of such attributes as water pressure and temperature on the eruption process, and to determine the rate of cooling and emplacement of lava flows in the submarine environment. Investigations to date show that the confining water pressure and the buoyancy effects of the surrounding water significantly affect the styles of volcanism on the ocean floor. In the case of Venusian volcanism, confining pressures will not be as great as that found at the ocean's abyssal plains, but nevertheless the general trend toward reducing magma vesiculation will hold true for Venus as well as the ocean floor. Furthermore, other analogs may also be found between submarine volcanism and Venusian activity.

  13. Silicic Submarine Eruptions: what can erupted pyroclasts tell us?

    NASA Astrophysics Data System (ADS)

    Carey, R.; Allen, S.; McPhie, J.; Fiske, R. S.; Tani, K.

    2013-12-01

    Our understanding of submarine volcanism is in its infancy with respect to subaerial eruption processes. Two fundamental differences between eruptions in seawater compared to those on land are that (1) eruptions occur at higher confining pressures, and (2) in a seawater medium, which has a higher heat capacity, density and viscosity than air. Together with JAMSTEC collaborators we have a sample suite of submarine pumice deposits from modern volcanoes of known eruption depths. This sample suite spans a spectrum of eruption intensities, from 1) powerful explosive caldera-forming (Myojin Knoll caldera); to 2) weakly explosive cone building (pre-caldera Myojin Knoll pumice and Kurose-Nishi pumice); to 3) volatile-driven effusive dome spalling (Sumisu knoll A); to 4) passive dome effusion (Sumisu knoll B and C). This sample suite has exceptional potential, not simply because the samples have been taken from well-constrained, sources but because they have similar high silica contents, are unaltered and their phenocrysts contain melt inclusions. Microtextural quantitative analysis has revealed that (i) clast vesicularities remain high (69-90 vol.%) regardless of confining pressure, mass eruption rate or eruption style , (ii) vesicle number densities scale with inferred eruption rate, and (iii) darcian and inertial permeabilities of submarine effusive and explosive pyroclasts overlap with explosively-erupted subaerial pyroclasts.

  14. The three scales of submarine groundwater flow and discharge across passive continental margins

    USGS Publications Warehouse

    Bratton, John F.

    2010-01-01

    Increased study of submarine groundwater systems in recent years has provided a wealth of new data and techniques, but some ambiguity has been introduced by insufficient distinguishing of the relevant spatial scales of the phenomena studied. Submarine groundwater flow and discharge on passive continental margins can be most productively studied and discussed by distinct consideration of the following three spatial scales: (1) the nearshore scale, spanning approximately 0–10 m offshore and including the unconfined surficial aquifer; (2) the embayment scale, spanning approximately 10 m to as much as 10 km offshore and including the first confined submarine aquifer and its terminus; and (3) the shelf scale, spanning the width and thickness of the aquifers of the entire continental shelf, from the base of the first confined aquifer downward to the basement, and including influences of geothermal convection and glacio-eustatic change in sea level.

  15. Submarine lithification of carbonate sediments.

    PubMed

    Milliman, J D

    1966-08-26

    Recrystallized planktonic limestones from two guyots in the North Atlantic are in oxygen-isotopic equilibrium with their present ambient waters, suggesting submarine lithifica tion and recrystallization. The early stages of submarine lithification of carbonates may involve precipitation of, and replacement by, magnesium-rich calcite; with time this may invert to magnesium-poor calcite. This type of lithification probably requires very low rates of sediment accumulation.

  16. Solar Multiple Eruptions from a Confined Magnetic Structure

    NASA Astrophysics Data System (ADS)

    Lee, Jeongwoo; Liu, Chang; Jing, Ju; Chae, Jongchul

    2016-09-01

    How eruption can recur from a confined magnetic structure is discussed based on the Solar Dynamics Observatory observations of the NOAA active region 11444, which produced three eruptions within 1.5 hr on 2012 March 27. The active region (AR) had the positive-polarity magnetic fields in the center surrounded by the negative-polarity fields around. Since such a distribution of magnetic polarity tends to form a dome-like magnetic fan structure confined over the AR, the multiple eruptions were puzzling. Our investigation reveals that this event exhibits several properties distinct from other eruptions associated with magnetic fan structures: (i) a long filament encircling the AR was present before the eruptions; (ii) expansion of the open-closed boundary (OCB) of the field lines after each eruption was suggestive of the growing fan-dome structure, and (iii) the ribbons inside the closed magnetic polarity inversion line evolved in response to the expanding OCB. It thus appears that in spite of multiple eruptions the fan-dome structure remained undamaged, and the closing back field lines after each eruption rather reinforced the fan-dome structure. We argue that the multiple eruptions could occur in this AR in spite of its confined magnetic structure because the filament encircling the AR was adequate for slipping through the magnetic separatrix to minimize the damage to its overlying fan-dome structure. The result of this study provides a new insight into the productivity of eruptions from a confined magnetic structure.

  17. A fan tale, modern and ancient fans - A comparison

    SciTech Connect

    Fischer, P.J. ); Thor, D.R. ); Cherven, V.B.

    1991-02-01

    The Quaternary Conception fan of the Santa Barbara basin and the Upper Cretaceous Lathrop fan of the northern San Joaquin basin tell an interesting tale. Both fans show a well defined sequence stratigraphy of alternating low-stand, sand-rich units that alternate with thin high-stand silt units that drape and in-fill the surface topography of the previous sand-cycle. Isopachs made from detailed well log correlations (Lathrop) and seismic reflection data tied to borings (Conception) show that the fans are composed of a series of offset-stacked, elongate fan lobes. These lobes are similar in size. A major difference in the development of the two fans is the timing of tectonism. Concomitant tectonism uplifted the Conception fan lobes and resulted in localized erosion of high-stand silts beds and sand-on-sand lobe contacts. Tectonism and Lathrop occurred after fan deposition and provided the trapping structure-the Lathrop anticlinal fold. Following are some lessons to be learned from these and other fans the authors have studied: (1) Quaternary or modern' fans and ancient fans are similar. (2) Elongate sand-rich fan lobes separated by highstand silt units are typical of fans. (3) In addition to well-known techniques (seismic stratigraphy and detailed well log correlations), original reservoir pressures may be used to differentiate sequences and lobes (e.g., Lathrop). (4) Tectonism and erosion along the margin may limit traps to the uppermost lobe sequence (e.g., Conception). (5) An offset-stacked elongate fan lobe model is a valuable exploration and production tool.

  18. Storm-reworked shallow-marine fans in the Middle Triassic Baise area, South China

    NASA Astrophysics Data System (ADS)

    Wang, Jiahao; Xie, Xinong; Pang, Xiong; Liu, Baojun

    2017-03-01

    Shallow-marine fans have been analyzed for sedimentary characteristics and genetic mechanisms far less commonly than deep-marine fans. Based on outcrop observations, this study reveals that large-scale submarine fans in the Middle Triassic Baise area, south China, consisted of a braided channel-levee facies complex in the inner fans; sinuous channel-levee facies complex, overbank facies and crevasse splay facies in the medial fans; and sand sheet facies in the outer fans, which present different lithology assemblages and depositional successions. The lithofacies of dominant massive sandstone, secondary graded sandstone and laminated sandstone from bottom to top is similar to the Bouma sequence, indicative of gravity flow processes. However, the laminated sandstones mostly bear sedimentary structures of gutter casts, wave-generated ripple marks, hummocky cross-bedding, wave-generated cross-bedding and ripple bedding, and were thus attributed to frequent storm reworking processes. Moreover, discontinuous deposition recorded by abrupt sediment grain-size changes, distinct interfaces and divergent paleocurrent orientations occurred between the laminated sandstones and the underlying massive (or graded) sandstones. Accordingly, storm reworking processes together with abundant fossils of Daonella, Ammonite and Crinoidea indicate a shallow-marine paleo-environment. As a whole, this study provides a good example of large-scale shallow-marine fans and laminated sandstones resulted from storm reworking.

  19. Morphodynamics of submarine channel inception revealed by new experimental approach.

    PubMed

    de Leeuw, Jan; Eggenhuisen, Joris T; Cartigny, Matthieu J B

    2016-03-21

    Submarine channels are ubiquitous on the seafloor and their inception and evolution is a result of dynamic interaction between turbidity currents and the evolving seafloor. However, the morphodynamic links between channel inception and flow dynamics have not yet been monitored in experiments and only in one instance on the modern seafloor. Previous experimental flows did not show channel inception, because flow conditions were not appropriately scaled to sustain suspended sediment transport. Here we introduce and apply new scaling constraints for similarity between natural and experimental turbidity currents. The scaled currents initiate a leveed channel from an initially featureless slope. Channelization commences with deposition of levees in some slope segments and erosion of a conduit in other segments. Channel relief and flow confinement increase progressively during subsequent flows. This morphodynamic evolution determines the architecture of submarine channel deposits in the stratigraphic record and efficiency of sediment bypass to the basin floor.

  20. Morphodynamics of submarine channel inception revealed by new experimental approach

    PubMed Central

    de Leeuw, Jan; Eggenhuisen, Joris T.; Cartigny, Matthieu J. B.

    2016-01-01

    Submarine channels are ubiquitous on the seafloor and their inception and evolution is a result of dynamic interaction between turbidity currents and the evolving seafloor. However, the morphodynamic links between channel inception and flow dynamics have not yet been monitored in experiments and only in one instance on the modern seafloor. Previous experimental flows did not show channel inception, because flow conditions were not appropriately scaled to sustain suspended sediment transport. Here we introduce and apply new scaling constraints for similarity between natural and experimental turbidity currents. The scaled currents initiate a leveed channel from an initially featureless slope. Channelization commences with deposition of levees in some slope segments and erosion of a conduit in other segments. Channel relief and flow confinement increase progressively during subsequent flows. This morphodynamic evolution determines the architecture of submarine channel deposits in the stratigraphic record and efficiency of sediment bypass to the basin floor. PMID:26996440

  1. Morphology, acoustic characteristics, and Late Quaternary growth of conception Fan, Santa Barbara basin, California

    SciTech Connect

    Kraemer, S.M.C.

    1986-04-01

    A radial borderland-basin fan in the western half of the Santa Barbara basin, the Conception Fan, shows characteristics of a debris slope. More than 3000 mi of closely spaced (3.5 kHz) high-resolution profiles, 270 gravity cores, and 8 borings were used to map channel and fan morphology, and channel, levee, and lobe acoustic facies. Two major unconformities are recognized on the seismic profiles. The upper unconformity represents the 10-k.y.B.P. horizon. The lower unconformity is the erosional surface of the late Wisconsinan lowstand of sea level, 18-26 k.y.B.P. Eustasy and tectonism produced two pulses of deposition, each from a different point source, during the Flandrian transgression. Prior to the late Pleistocene, the Conception Fan was fed by one major canyon/channel system, above the western part of the fan. During the late Pleistocene, two small submarine canyons were cut into the slope 7 mi east. Four major channels, smaller than the western channel system, were incised into the fan surface, indicating the eustatic decrease in sediment input. The fault-controlled western canyon (Sacate) fed all but the eastern channel. Faulting and slumping on the slope cut the eastern canyon (Gaviota) and formed the eastern channel. Numerous slope gullies influenced eastern canyon and channel development. Holocene currents rounding Point Conception have winnowed fine sediments in the western channel region, resulting in hummocky topography and the scoured appearance of the channel. Hemipelagic deposition dominates the lower-middle and lower fan of the eastern part of the fan. The western part of the fan seems to be receiving slope-like deposits over the relict fan surface.

  2. Large Alluvial Fans on Mars

    NASA Technical Reports Server (NTRS)

    Moore, Jeffrey M.; Howard, Alan D.

    2004-01-01

    Several dozen distinct alluvial fans, 10 to greater than 40 km long downslope are observed exclusively in highlands craters. Within a search region between 0 deg. and 30 deg. S, alluvial fan-containing craters were only found between 18 and 29 S, and they all occur at around plus or minus 1 km of the MOLA-defined Martian datum. Within the study area they are not randomly distributed but instead form three distinct clusters. Fans typically descend greater than 1 km from where they disgorge from their alcoves. Longitudinal profiles show that their surfaces are very slightly concave with a mean slope of 2 degrees. Many fans exhibit very long, narrow low-relief ridges radially oriented down-slope, often branching at their distal ends, suggestive of distributaries. Morphometric data for 31 fans was derived from MOLA data and compared with terrestrial fans with high-relief source areas, terrestrial low gradient alluvial ramps in inactive tectonic settings, and older Martian alluvial ramps along crater floors. The Martian alluvial fans generally fall on the same trends as the terrestrial alluvial fans, whereas the gentler Martian crater floor ramps are similar in gradient to the low relief terrestrial alluvial surfaces. For a given fan gradient, Martian alluvial fans generally have greater source basin relief than terrestrial fans in active tectonic settings. This suggests that the terrestrial source basins either yield coarser debris or have higher sediment concentrations than their Martian counterpoints. Martian fans and Basin and Range fans have steeper gradients than the older Martian alluvial ramps and terrestrial low relief alluvial surfaces, which is consistent with a supply of coarse sediment. Martian fans are relatively large and of low gradient, similar to terrestrial fluvial fans rather than debris flow fans. However, gravity scaling uncertainties make the flow regime forming Martian fans uncertain. Martian fans, at least those in Holden crater, apparently

  3. Comparison of modern Mississippi fan with selected ancient fans

    SciTech Connect

    Shanmugam, G.; Moiola, R.J.; McPherson, J.G.; O'Connell, S.

    1988-09-01

    A comparison of the modern passive-margin Mississippi fan (DSDP Leg 96) with selected ancient active-margin fans reveals major differences in turbidite facies associations and seismic characteristics of the lower fan area. The lower Mississippi fan is composed of channel (facies B and F) and nonchannel sequences (facies C. and D), whereas lower fan areas of ancient active-margin fans are characterized by nonchannelized, thickening-upward depositional lobes (facies C and D) with sheetlike geometry. An absence of depositional lobes in the lower Mississippi fan is also suggested by a lack of mounded seismic reflections. Continuous and parallel seismic reflections of the lower Mississippi fan may represent sheet sands, but not those of true depositional lobes. In mature passive-margin fans, long, sinuous channels develop as a consequence of low gradients and the transport of sediment with a relatively low sand/mud ratio, and these channels develop lenticular sand bodies. In contrast, channels in active-margin fans are short and commonly braided as a result of high gradients and the transport of sediment with a relatively high sand/mud ratio. Braided channels characteristically develop sheetlike sand bodies.

  4. Tectonic control of Cretaceous gravity deposits and submarine Valleys in the subalpine basin, French western Alps

    SciTech Connect

    Philippe, J.; Beaudoin, B.; Fries, G.; Parize, O.

    1988-08-01

    The Late Jurassic-Early Cretaceous series of the French subalpine basin is characterized by alternating limestones and marls with numerous, thick gravity-flow deposits (carbonate debris flows and slumps, siliciclastic grain flows, turbidites). These gravity deposits originate from platforms and slopes and come through the basin via several parallel canyons and submarine valleys. Some carbonate (Berriasian) and siliciclastic (Aptian) deep-sea fans are built at the canyon mouth during intense activity of the canyons and reworking of the sediments. The tectonic control of the gravity deposits is demonstrated by the position and filling of the submarine valleys all along the Cretaceous. The submarine valleys correspond systematically to the lower part of extensional tilted blocks; the gravity deposits come along the main syn-sedimentary normal faults delimiting these tilted blocks. The gravity deposits go from one tilted block to another through some synsedimentary passes which are induced by slight folding, perhaps related to an early diapirism at some nodes of extensional faults. The canyon-like valleys are due to very strong erosion when a submarine valley cuts of the higher part of a tilted block. The gravity deposits are stacked atop each other and progressively fill the valleys. Thus the cutting and filling of the submarine valleys and canyons on occasions during the Early Cretaceous are explained by a permanent synsedimentary activity. These Jurassic and Cretaceous extensional structures are later reactivated by inversion during Tertiary compressional movements.

  5. Timing of occurrence of large submarine landslides on the Atlantic Ocean margin

    USGS Publications Warehouse

    Lee, H.J.

    2009-01-01

    Submarine landslides are distributed unevenly both in space and time. Spatially, they occur most commonly in fjords, active river deltas, submarine canyon-fan systems, the open continental slope and on the flanks of oceanic volcanic islands. Temporally, they are influenced by the size, location, and sedimentology of migrating depocenters, changes in seafloor pressures and temperatures, variations in seismicity and volcanic activity, and changes in groundwater flow conditions. The dominant factor influencing the timing of submarine landslide occurrence is glaciation. A review of known ages of submarine landslides along the margins of the Atlantic Ocean, augmented by a few ages from other submarine locations shows a relatively even distribution of large landslides with time from the last glacial maximum until about five thousand years after the end of glaciation. During the past 5000??yr, the frequency of occurrence is less by a factor of 1.7 to 3.5 than during or shortly after the last glacial/deglaciation period. Such an association likely exists because of the formation of thick deposits of sediment on the upper continental slope during glacial periods and increased seismicity caused by isostatic readjustment during and following deglaciation. Hydrate dissociation may play a role, as suggested previously in the literature, but the connection is unclear.

  6. Fans on Crater Rims

    NASA Image and Video Library

    2016-12-14

    Gas under pressure will choose an easy escape route. In this image, the terrain is covered with a seasonal layer of dry ice. The weak spots, for gas sublimating from the bottom of the seasonal ice layer to escape, appear to be around craters, where the surface was broken and pulverized by an impact. Fans of surface material deposited on top of the seasonal ice layer show where the escape vents are. http://photojournal.jpl.nasa.gov/catalog/PIA21271

  7. Fan Blade Development

    DTIC Science & Technology

    1982-09-01

    following. o Injection Molding o Reaction Injection Molding o Rotational Molding o Blow Molding j o Thermoforming o Compressive Molding I GARD’s...process investigation for the alternate material PVK indicated Sthat of the above, injection molding and thermoforming are the two processes directly... thermoforming does require some secondary trimming after the part is removed. The preheated temperature for the fan material in the thermoforming

  8. Alluvial Fan, China

    NASA Image and Video Library

    2017-09-27

    Image taken 5/2/2002 by ASTER: A vast alluvial fan blossoms across the desolate landscape between the Kunlun and Altun mountain ranges that form the southern border of the Taklimakan Desert in China's XinJiang Province. This image can be found on ASTER Path 143 Row 34, center: 37.43 N, 84.30 E. To learn more about the Landsat satellite go to: landsat.gsfc.nasa.gov/

  9. Controls on modern tributary-junction alluvial fan occurrence and morphology: High Atlas Mountains, Morocco

    NASA Astrophysics Data System (ADS)

    Stokes, Martin; Mather, Anne E.

    2015-11-01

    Modern tributary-junction alluvial fans (cone-shaped depositional landforms formed in confined valley settings) were analysed from a 20-km-long reach of the Dades River in the distal part of the fold-thrust belt region in the south-central High Atlas Mountains of Morocco. Here, a deeply dissected network of ephemeral tributary streams and a perennial trunk drainage characterised by an arid mountain desert climate are configured onto a folded and thrust faulted Mesozoic sedimentary sequence. Out of 186 tributary streams, only 29 (16%) generated alluvial fans at their tributary junctions. The fan-generating catchments possess higher relief, longer lengths, lower gradients, and larger areas than nonfan-generating catchments. Whilst geologically, fan-generating catchments are underlain by folded/steeply dipping weak bedrock conducive to high sediment yield. Tributary-junction fans are built from debris flow or fluvial processes into open or confined canyon trunk valley settings. The proximity of the perennial trunk drainage combined with the valley morphology produces lobate or foreshortened trimmed fan forms. Analysis of fan (area, gradient, process), catchment (area, relief, length, gradient), and tributary valley (width) variables reveals weak morphometric relationships, highlighted by residual plots that show dominance of smaller and lower gradient than expected fan forms. These morphometric relationships can be explained by interplay between the catchment and trunk drainage geology, morphology, climate, and flood regime that are combined into a conceptual 'build and reset' model. Ephemeral tributary-junction fans develop progressively during annual localised winter-spring storm events, attempting to build towards a morphological equilibrium. However, the fans never reach an equilibrium morphological form as they are reset by rare (> 10 year) large floods along the River Dades that are linked to regional incursions of Atlantic low pressure troughs. The model

  10. Exhaust Fan Temperature Switch

    SciTech Connect

    Ball, G.S.; /Fermilab

    1989-05-11

    The 13000 cfm 'emergency' vent fan must be protected from over cooling which would result in a mechanical failure. Over cooling could result from a catastrophic cryogen release from the cryostat(s) or Argon Storage Dewar. In order to protect the fan, a VPT has been calibrated for -31 C to open a switch which sends a signal to allow warm gas to enter the sump by means of a motor controlled louver installed at 'sidewalk level' in the ductwork between the assembly hall and the Argon Dewar Enclosure. The bulb of the VPT is enclosed in a thermal well and will be placed in the gas stream directly above the fan. The switching unit will be mounted nearby on the wall in order to isolate it from vibrational effects. Should the fan be activated due to a cryogen release, it should not experience any problems when operating above -40 C. The switch was set and checked in a saturated calcium chloride solution cooled to -31 C by running cold gaseous Nitrogen through a copper tube coiled in a dewar. Switching temperature was measured by a thermocouple tied to the VPT bulb. The thermocouple was checked in LN2, in an ice water bath, and against an ordinary thermometer (which was assumed to be accurate to plus or minus 0.3 C) at room temperature. The results are shown below in 'Table 1' By interpolation of the data, thermocouple error at -31.0 C was found to be 0.43 C on the warm side. Since this error was small, it was ignored. 'Table 2' shows the results of the tests. Ten readings were taken with the switch wired in the 'normally open' mode. This results in a signal at room temperature. The worst deviation was 2.5 C. Three readings were then taken from the 'normally closed' wiring arrangement (the way it will be wired for installation). The greatest deviation was 1.2 C. The next day, the switch was checked five times wired in the 'normally open' configuration. The greatest error was 1.1 C. A graph has been prepared showing the switching and resetting temperatures. The errors these

  11. An investigation of the physical factors controlling the sense of secondary flow circulation within submarine meanders

    NASA Astrophysics Data System (ADS)

    Darby, S. E.; Dorrell, R. M.; Peakall, J.; Sumner, E.; Parsons, D. R.; Wynn, R.

    2012-12-01

    within submarine canyon-fan networks. Our findings highlight the importance of (i) Coriolis, (ii) flow baroclinicity, and (iii) the dimensionality of the space-time continuum in controlling the sense of helical flow in submarine meanders. Specifically, the new model presented here suggests that the propensity for the occurrence of meander 'reversed' flow circulations in canyon-fan networks may be considerably greater than recently advocated.

  12. Sediment-laden flow induced submarine cable failures off southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Su, C. C.

    2012-04-01

    Taiwan is located on the convergent boundary between the Eurasian and Philippine Sea plates, where has a highly frequency of earthquakes. Furthermore, the interaction between the largest continent (Eurasia Continent) and ocean (Pacific Ocean) leads to torrential-rain-induced flooding in the plume rain (May-June) and typhoon seasons (July-October). According to statistics from Water Resources Agency, in the last few decades, the mean annual sediment load was 384 million tons from the island of Taiwan into the sea. Off southwestern Taiwan, two major submarine canyons, the Gaoping submarine canyon (GPSC) and Fangliao submarine canyon (FLSC), are incising from continental shelf to deep sea floor and both of them transport considerable amounts of sediment to the South China Sea. In contrast to the GPSC which is directly connected to the Gaoping River, the FLSC which is smaller, younger and confined to the slope, does not associate with any river on land. Since 2006, southern Taiwan has been through several big typhoons and earthquakes which triggered submarine landslides and turbidity currents and damaged many submarine cables. The analytical results from sediment cores which taken from the GPSC and FLSC during 2005 to 2010 show these submarine cable break events may caused by different processes. In the upper GPSC, hyperpycnal flow might be the major process which caused the cable damages. On the contrary, cable failures in FLSC are due to sediment liquefaction.

  13. Observational Analysis of Coronal Fans

    NASA Technical Reports Server (NTRS)

    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.

  14. Minturn and Sangre de Cristo Formations of southern Colorado: a prograding fan-delta to alluvial-fan sequence shed from ancestral Rocky Mountains

    SciTech Connect

    Lindsey, D.A.; Clark, R.F.; Ashe, S.J.; Flores, R.J.

    1983-08-01

    The Pennsylvanian Minturn and Pennsylvanian-Permian Sangre de Cristo Formations of the northern Sangre de Cristo Mountains comprise a 3,800-m (12,500-ft) thick progradational sequence of coarse clastic sediments shed into a basin on the northeastern side of the late Paleozoic San Luis-Uncompahgre highland. From bottom to top, the mostly marine Minturn Formation contains probable deltaic (700 m, 2,300 ft), mixed fan-delta and prodelta (800 m, 2,600 ft), and fan-delta (600 m, 2,000 ft) deposits; the mostly continental Sangre de Cristo Formation contains distal alluvial fan (600 m, 2,000 ft) and proximal alluvial fan (1,100m 3,600 ft) deposits. At least three episodes of uplift are indicated by the distribution of unconformities, geometry of intertonguing facies, and abrupt vertical changes in facies. The deltaic and mixed fan-delta and prodelta deposits of the lower and middle parts of the Minturn Formation consist of coarsening-upward cycles 30 to 300 m (100 to 1,000 ft) thick of shale, siltstone, sandstone, and conglomeratic sandstone. The mixed deposits in the middle part of the Minturn contain cycles of shale, proximalturbidite sandstones, and conglomeratic sandstone; such cycles are interpreted as deposits of submarine fans overridden by fan deltas. Continental deposits of the lower member of the Sangre de Cristo Formation consist of fining-upward cycles 2 to 37 m (6.5 to 121 ft) thick of cross-bedded conglomerate, sandstone, and siltstone deposited by braided streams on the distal parts of alluvial fans.

  15. Fan-structure wave as a source of earthquake instability

    NASA Astrophysics Data System (ADS)

    Tarasov, Boris

    2015-04-01

    Today frictional shear resistance along pre-existing faults is considered to be the lower limit on rock shear strength at confined compression corresponding to the seismogenic layer. This determines the lithospheric strength and the primary earthquake mechanism associated with frictional stick-slip instability on pre-existing faults. This paper introduces a recently identified shear rupture mechanism providing a paradoxical feature of hard rocks - the possibility of shear rupture propagation through the highly confined intact rock mass at shear stress levels significantly less than frictional strength. In the new mechanism the rock failure, associated with consecutive creation of small slabs (known as 'domino-blocks') from the intact rock in the rupture tip, is driven by a fan-shaped domino structure representing the rupture head. The fan-head combines such unique features as: extremely low shear resistance (below the frictional strength), self-sustaining stress intensification in the rupture tip (providing easy formation of new domino-blocks), and self-unbalancing conditions in the fan-head (making the failure process inevitably spontaneous and violent). An important feature of the fan-mechanism is the fact that for the initial formation of the fan-structure an enhanced local shear stress is required, however, after completion of the fan-structure it can propagate as a dynamic wave through intact rock mass at shear stresses below the frictional strength. Paradoxically low shear strength of pristine rocks provided by the fan-mechanism determines the lower limit of the lithospheric strength and favours the generation of new faults in pristine rocks in preference to frictional stick-slip instability along pre-existing faults. The new approach reveals an alternative role of pre-existing faults in earthquake activity: they represent local stress concentrates in pristine rock adjoining the fault where special conditions for the fan-mechanism nucleation are created

  16. High fidelity phase locked PIV measurements analysing the flow fields surrounding an oscillating piezoelectric fan

    NASA Astrophysics Data System (ADS)

    Jeffers, Nicholas; Nolan, Kevin; Stafford, Jason; Donnelly, Brian

    2014-07-01

    Piezoelectric fans have been studied extensively and are seen as a promising technology for thermal management due to their ability to provide quiet, reliable cooling with low power consumption. The fluid mechanics of an unconfined piezoelectric fan are complex which is why the majority of the literature to date confines the fan in an attempt to simplify the flow field. This paper investigates the fluid mechanics of an unconfined fan operating in its first vibration frequency mode. The piezoelectric fan used in this study measures 12.7mm × 70mm and resonates at 92.5Hz in air. A custom built experimental facility was developed to capture the fan's flow field using phase locked Particle Image Velocimetry (PIV). The phase locked PIV results are presented in terms of vorticity and show the formation of a horse shoe vortex. A three dimensional A2 criterion constructed from interpolated PIV measurements was used to identify the vortex core in the vicinity of the fan. This analysis was used to clearly identify the formation of a horse shoe vortex that turns into a hairpin vortex before it breaks up due to a combination of vortex shedding and flow along the fan blade. The results presented in this paper contribute to both the fluid dynamics and heat transfer literature concerning first mode fan oscillation.

  17. Fan Cart: The Next Generation

    NASA Astrophysics Data System (ADS)

    Lamore, Brian

    2016-10-01

    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 in developing the `E' portion of your and your students' STEM (science, technology, engineering, and math) skills, one way to accomplish this is to revisit the DIY fan cart. In this article I share a design of a new edition of the DIY fan cart and some ideas for incorporating the engineering design process into your high school curriculum.

  18. Fan Noise Reduction: An Overview

    NASA Technical Reports Server (NTRS)

    Envia, Edmane

    2001-01-01

    Fan noise reduction technologies developed as part of the engine noise reduction element of the Advanced Subsonic Technology Program are reviewed. Developments in low-noise fan stage design, swept and leaned outlet guide vanes, active noise control, fan flow management, and scarfed inlet are discussed. In each case, a description of the method is presented and, where available, representative results and general conclusions are discussed. The review concludes with a summary of the accomplishments of the AST-sponsored fan noise reduction research and a few thoughts on future work.

  19. Improved testing safeguards fan reliability

    SciTech Connect

    Chedister, W.C.; Long, J.

    1995-04-01

    This article describes how new NDT inspection services and materials help power plant managers avoid costly fan failures. A single broken or disconnected fan blade can induce vibration that renders a fan useless. While power plant fan repair and replacement costs can rise as high as $500,000, the cost is small compared to lost revenue from a long unscheduled outage to complete the job. It is not surprising then that non-destructive testing (NDT) is essential in detecting system component trouble. New-generation test materials and highly experienced service specialists are substantially improving inspection effectiveness.

  20. Fan and pump noise control

    NASA Technical Reports Server (NTRS)

    Misoda, J.; Magliozzi, B.

    1973-01-01

    The development is described of improved, low noise level fan and pump concepts for the space shuttle. In addition, a set of noise design criteria for small fans and pumps was derived. The concepts and criteria were created by obtaining Apollo hardware test data to correlate and modify existing noise estimating procedures. A set of space shuttle selection criteria was used to determine preliminary fan and pump concepts. These concepts were tested and modified to obtain noise sources and characteristics which yield the design criteria and quiet, efficient space shuttle fan and pump concepts.

  1. Controls on sediment transfer and storage on debris flow fans

    NASA Astrophysics Data System (ADS)

    Schürch, Peter; Densmore, Alexander L.; Rosser, Nick J.; McArdell, Brian W.

    2010-05-01

    generally comparable to the fan-scale lag rates in both sign and magnitude, indicating that volume exchange between channel and bed is typically fairly uniform down-fan in any given flow. Accordingly, flows of similar volume at the fan apex can evolve in a divergent manner, becoming significantly larger or smaller while crossing the fan surface. Because debris-flow hazard and depositional pattern are highly dependent on the degree of flow confinement within a channel, and in turn on the volume of individual flows, the results have important implications for the short- to medium-term evolution of fan systems, and can be used to inform how we manage debris flows on fan surfaces as hazards.

  2. Dark Spots and Fans

    NASA Technical Reports Server (NTRS)

    2006-01-01

    As winter turns to spring at the south polar ice cap of Mars, the rising sun reveals dark spots and fans emerging from the cold polar night. Using visual images (left) and temperature data (right) from the Thermal Emission Imaging system on NASA's Mars Odyssey orbiter, scientists have built a new model for the origin of the dark markings. Scientists propose the markings come from dark sand and dust strewn by high-speed jets of carbon-dioxide gas. These erupt from under a layer of carbon-dioxide ice that forms each Martian winter.

  3. Field of Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Subimage #1 Figure 1 Subimage #2 Figure 2 [figure removed for brevity, see original site] [figure removed for brevity, see original site] Anaglyph Figure 3 Subimage #3 Figure 4

    At the very beginning of spring in the southern hemisphere on Mars the ground is covered with a seasonal layer of carbon dioxide ice. In this image there are two lanes of undisturbed ice bordered by two lanes peppered with fans of dark dust.

    When we zoom in to the subimage (figure 1), the fans are seen to be pointed in the same direction, dust carried along by the prevailing wind. The fans seem to emanate from spider-like features.

    The second subimage (figure 2) zooms in to full HiRISE resolution to reveal the nature of the 'spiders.' The arms are channels carved in the surface, blanketed by the seasonal carbon dioxide ice. The seasonal ice, warmed from below, evaporates and the gas is carried along the channels. Wherever a weak spot is found the gas vents to the top of the seasonal ice, carrying along dust from below.

    The anaglyph (figure 3) of this spider shows that these channels are deep, deepening and widening as they converge. Spiders like this are often draped over the local topography and often channels get larger as they go uphill. This is consistent with a gas eroding the channels.

    A different channel morphology is apparent in the lanes not showing fans. In these regions the channels are dense, more like lace, and are not radially organized. The third subimage (figure 4) shows an example of 'lace.'

    Observation Geometry Image PSP_002532_0935 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 09-Feb-2007. The complete image is centered at -86.4 degrees latitude, 99.1 degrees East longitude. The range to the target site was 276.1 km (172.6 miles). At this distance the image scale is

  4. Field of Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Subimage #1 Figure 1 Subimage #2 Figure 2 [figure removed for brevity, see original site] [figure removed for brevity, see original site] Anaglyph Figure 3 Subimage #3 Figure 4

    At the very beginning of spring in the southern hemisphere on Mars the ground is covered with a seasonal layer of carbon dioxide ice. In this image there are two lanes of undisturbed ice bordered by two lanes peppered with fans of dark dust.

    When we zoom in to the subimage (figure 1), the fans are seen to be pointed in the same direction, dust carried along by the prevailing wind. The fans seem to emanate from spider-like features.

    The second subimage (figure 2) zooms in to full HiRISE resolution to reveal the nature of the 'spiders.' The arms are channels carved in the surface, blanketed by the seasonal carbon dioxide ice. The seasonal ice, warmed from below, evaporates and the gas is carried along the channels. Wherever a weak spot is found the gas vents to the top of the seasonal ice, carrying along dust from below.

    The anaglyph (figure 3) of this spider shows that these channels are deep, deepening and widening as they converge. Spiders like this are often draped over the local topography and often channels get larger as they go uphill. This is consistent with a gas eroding the channels.

    A different channel morphology is apparent in the lanes not showing fans. In these regions the channels are dense, more like lace, and are not radially organized. The third subimage (figure 4) shows an example of 'lace.'

    Observation Geometry Image PSP_002532_0935 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 09-Feb-2007. The complete image is centered at -86.4 degrees latitude, 99.1 degrees East longitude. The range to the target site was 276.1 km (172.6 miles). At this distance the image scale is

  5. Subjective symptoms and postural control during a disabled submarine simulation.

    PubMed

    Cymerman, A; Young, A J; Francis, T J R; Wray, D D; Ditzler, D T; Stulz, D; Bovill, M; Muza, S R

    2002-01-01

    To simulate conditions aboard a disabled submarine, 7 submariners were confined for 5 d to a normobaric environment of 16.75% O2, 2.5% CO2, 4 degrees C, and 85% relative humidity (RH). After 2 control days and 1 d of hypoxia, the remaining environmental conditions were imposed for the next 5 d, followed by 1 additional day of just hypoxia. Daily morning symptoms were assessed using the Environmental Symptoms Questionnaire (ESQ). Postural stability was determined on 4 occasions using a computerized balance system: control period, after 2.7 and 4.7 d of steady-state test conditions, and after 5.7 d (with return to normal ambient temp, RH, and CO2). Three balance tests were performed: eyes open, eyes closed, and a dynamic test. Postural stability deteriorated after 2.7 d (87% eyes open, P < 0.001 and 26% eyes closed, P = 0.01). ESQ symptom subsets for acute mountain sickness, exertion, fatigue, alertness, and ear/nose/throat were not significantly different. Cold symptom subsets were increased after 3-7 d (P < 0.001); distress and muscle discomfort subsets after 7 d (P = 0.02). Continued exposure to the combination of cold and hypoxia elicited subjective symptom changes and disturbances in postural stability that are statistically significant. These observations may be of practical importance when tasks aboard a disabled submarine involve balance and mobility.

  6. A Pleistocene coastal alluvial fan complex produced by Middle Pleistocene glacio-fluvial processes

    NASA Astrophysics Data System (ADS)

    Adamson, Kathryn; Woodward, Jamie; Hughes, Philip; Giglio, Federico; Del Bianco, Fabrizio

    2014-05-01

    A coarse-grained alluvial fan sequence at Lipci, Kotor Bay, in western Montenegro, provides a sedimentary record of meltwater streams draining from the Orjen Massif (1,894 m a.s.l.) to the coastal zone. At Lipci sedimentary evidence and U-series ages have been used alongside offshore bathymetric imagery and seismic profiles to establish the size of the fan and constrain the nature and timing of its formation. Establishing the depositional history of such coastal fans is important for our understanding of cold stage sediment flux from glaciated uplands to the offshore zone, and for exploring the impact of sea level change on fan reworking. There is evidence of at least four phases of Pleistocene glaciation on the Orjen massif, which have been U-series dated and correlated to MIS 12, MIS 6, MIS 5d-2 and the Younger Dryas. A series of meltwater channels delivered large volumes of coarse- and fine-grained limestone sediment from the glaciated uplands into the Bay of Kotor. At the southern margin of the Orjen massif, a series of large (>700 m long) alluvial fans has developed. Some of these extend offshore for up to 600 m. Lipci fan lies downstream of end moraines in the valley immediately above, which were formed by an extensive outlet glacier of the Orjen ice cap during MIS 12. The terrestrial deposits are part of the fan apex (50 m a.s.l.) that lies at the foot of a steep bedrock channel, but the majority of the fan is now more than 25 m below sea level. The terrestrial fan sediments are strongly cemented by multiple generations of calcite precipitates: the oldest U-series ages are infinite indicating that the fan is >350 ka in age. These ages are in agreement with alluvial sedimentary evidence and U-series ages from other fluvial units on Mount Orjen. The terrestrial portion of the Lipci fan surface contains several channels. These are well preserved due to cementation with calcium carbonate. Submarine imagery indicates that the now submerged portion of the fan also

  7. Submarine geothermal resources

    USGS Publications Warehouse

    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

  8. Design features of fans, blowers, and compressors

    NASA Astrophysics Data System (ADS)

    Cheremisinoff, N. P.; Cheremisinoff, P. N.

    Fan engineering and compression machines are discussed. Basic aspects of fan performance and design are reviewed, and the design and performance characteristics of radial-flow fans, axial-flow fans, and controllable pitch fans are examined in detail. Air-conditioning systems are discussed, and noise, vibration, and mechanical considerations in fans are extensively examined. The thermodynamic principles governing compression machines are reviewed, and piston compressors, rotary compressors, blowers, and centrifugal compressors are discussed.

  9. Sediment transport processes in the Gulf of Alaska: a morphological analysis of channel and fan sedimentary features

    NASA Astrophysics Data System (ADS)

    Morey, S.; Swartz, J. M.; Gulick, S. P. S.

    2016-12-01

    The Alaskan Abyssal Plain is home to three active channel/fan systems: the Surveyor, Chirikov, and Baranof systems. Individual studies of the Surveyor and Baranof fans indicate that these systems derive their sediments from the glacially dominated Northeast Pacific North American coast. The Pleistocene aged sediments found in the Surveyor Fan record some of the highest sediment accumulation rates (up to 130 cm/kyr) ever documented and show that this system is one of the youngest recognized large submarine fans. Further, the Surveyor and Baranof systems are two of the largest submarine fans in the world and their development has been significantly influenced by climatic and tectonic forcing. Specifically, these fans either developed or expanded with increased glacial activity in the Pleistocene that resulted in increased sediment flux to the Gulf of Alaska. While this influence is widely accepted, the depositional processes within the modern and past systems are poorly understood. A thorough investigation of these deep ocean sediment transport processes can further inform our understanding of this high-latitude source-to-sink system. Although the existence of multiple fans on a margin isn't exclusive to Alaska, the slope of the Gulf's basin floor indicates a relatively unique condition. As channels in the Gulf of Alaska carry sediment away from the continental slope margin—parallel to the Aleutian Trench—the basin floor between the adjacent channels generally slopes towards the Aleutian Trench. The presence of large scale bedforms on this sloped surface indicate the potential for significant sediment remobilization on the basin floor between active channels. Additionally, these systems are characterized by higher relief western channel banks and varying states of equilibrium, as well as differing degrees of sinuosity and channel width/depth. We intend to quantify these and other morphological features in the Gulf of Alaska with the goal of investigating active

  10. Fan Cart: The Next Generation

    ERIC Educational Resources Information Center

    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…

  11. Fan Cart: The Next Generation

    ERIC Educational Resources Information Center

    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…

  12. Obstacle avoidance sonar for submarines

    NASA Astrophysics Data System (ADS)

    Dugas, Albert C.; Webman, Kenneth M.

    2002-05-01

    The Advanced Mine Detection Sonar (AMDS) system was designed to operate in poor environments with high biological and/or shallow-water boundary conditions. It provides increased capability for active detection of volume, close-tethered, and bottom mines, as well as submarine and surface target active/passive detection for ASW and collision avoidance. It also provides bottom topography mapping capability for precise submarine navigation in uncharted littoral waters. It accomplishes this by using advanced processing techniques with extremely narrow beamwidths. The receive array consists of 36 modules arranged in a 15-ft-diameter semicircle at the bottom of the submarine sonar dome to form a chin-mounted array. Each module consists of 40 piezoelectric rubber elements. The modules provide the necessary signal conditioning to the element data prior to signal transmission (uplink) through the hull. The elements are amplified, filtered, converted to digital signals by an A/D converter, and multiplexed prior to uplink to the inboard receiver. Each module also has a downlink over which it receives synchronization and mode/gain control. Uplink and downlink transmission is done using fiberoptic telemetry. AMDS was installed on the USS Asheville. The high-frequency chin array for Virginia class submarines is based on the Asheville design.

  13. CF6 fan performance improvement

    NASA Technical Reports Server (NTRS)

    Patt, R. F.; Reemsnyder, D. C.

    1980-01-01

    A significant portion of the NASA-sponsored Performance Improvement Program for the CF6 engine was the development of an improved fan concept. This involved aerodynamic redesign of the CF6 fan blade to increase fan efficiency while retaining the mechanical integrity, operability, and acoustic characteristics of the existing blade. A further improvement in performance was obtained by adding a fan case stiffener ring to decouple blade-case vibrational characteristics, permitting a significant reduction in running tip clearance. Engine testing was performed to establish the performance, mechanical and acoustic properties of the new design relative to the current fan, and to establish power management characteristics for the CF6-50C2/E2 engine. A significant improvement in cruise power SFC of 1.8 percent was demonstrated in Sea Level testing projected to altitude flight conditions.

  14. Design definition study of a lift/cruise fan technology V/STOL aircraft. Volume 1: Navy operational aircraft

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Aircraft were designed and sized to meet Navy mission requirements. Five missions were established for evaluation: anti-submarine warfare (ASW), surface attack (SA), combat search and rescue (CSAR), surveillance (SURV), and vertical on-board delivery (VOD). All missions were performed with a short takeoff and a vertical landing. The aircraft were defined using existing J97-GE gas generators or reasonable growth derivatives in conjunction with turbotip fans reflecting LF460 type technology. The multipurpose aircraft configuration established for U.S. Navy missions utilizes the turbotip driven lift/cruise fan concept for V/STOL aircraft.

  15. 30. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONNECTICUT. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONNECTICUT. 2 JUNE 1930. SUBMARINE TRAINING TANK - STEELWORK 98% COMPLETE; BRICKWORK 95% COMPLETE, PIPING 10% IN PLACE. LOOKING NORTH. CONTRACT NO. Y-1539-ELEVATOR, SUBMARINE ESCAPE TANK.' - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

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

    NASA Astrophysics Data System (ADS)

    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

  17. The lithostratigraphy of a marine kame delta-outwash fan complex at Pease AFB, Newington, NH

    SciTech Connect

    Dineen, R.J.; Manning, S.; McGeehan, K. )

    1993-03-01

    The overburden stratigraphy at Pease AFB is based on over 1,200 wells, borings, piezometers, and test pits, and includes five lithologic units: Fill, Upper Sand (US), Marine Clay and Silt (MCS), Lower Sand (LS), and Till (GT). The US is a yellow brown, poorly sorted sand to silty sand and is massive to laminated, and locally has hummocky bedding. The MCS (the Presumpscot Formation) is a dark gray, massive to laminated sandy to silty clay, and is locally interbedded with silty sand. The MCS contains a trace of organic matter, primarily as fine particles of peat. The LS is a gray to brown, poorly sorted, silty sand to gravelly sand that is massive to planar bedded and locally grades down into GT and/or upward into MCS. The GT consists of a massive to crudely bedded dark gray to dark brown, very poorly sorted, sandy silt to gravelly, silty sand. The US, MCS, LS and upper part of the GT were deposited in a marine environment at or near the ice margin. Pease AFB is built on two large fans of gravelly sand (LS plus US) that are bordered to the east by NW-SE till ridges (drumlins ). The northern-most fan is flat-topped with a surface elevation of 30 m ASL. The southern fan is more hummocky, with a surface elevation of 18.5 m ASL. Both fans coarsen towards the NW, and are interbedded with MCS towards the SE. The apices of the fans overlie deeply-scoured troughs in the rock surface. The fans are interpreted to be kame deltas or submarine outwash fans that are deposited along the retreating Wisconsinan ice margin by concentrated meltwater flow. Later, the US may have been deposited by marine shoreface erosion of the emergent fans as the ice front retreated and sea level fell.

  18. The transfer of river load to deep-sea fans: A quantitative approach

    SciTech Connect

    Wetzel, A. )

    1993-10-01

    Submarine fans and turbidite systems are major petroleum reservoirs in many sedimentary basins worldwide. The size of a river-fed deep-sea fan is controlled mainly by the amount of sediment available from a terrestrial source, whereas sea level fluctuations only trigger mass transfer to the deep sea. The deposition rate and fan length correlate for most fans formed on abyssal plains. Fan size is independent of depositional environment (lake or sea), time span, or geological period, which may be characterized by different amplitudes and frequencies of sea level fluctuations. In climatically stable regions such as the tropics about 25 [+-] 10% of the suspended river load reaching the river mouth is transported to the deep sea over the long term. The type of river mouth affects the amount of material transported to the deep sea; estuaries with deeply incised canyons may transfer 6-8 times more material than fluvial-dominated and lobate deltas, provided the suspended river load is equal in both cases. For most river-fed deep-sea fans, a well-defined geometry develops on unconfined abyssal plains. The width/length ratio is about 0.2 at the base of the slope, and reaches a maximum of 0.5 farther downward. This is in good agreement with flume experiments. The volume of such fans resting on a planar base is roughly 0.35 [times] area [times] maximum thickness. The quantitative relationships of fans with respect to geometry, deposition rate, and river suspended discharge may provide some basic for basin modeling and calculation of the sediment budget of erosional-depositional systems.

  19. Fan noise prediction assessment

    NASA Technical Reports Server (NTRS)

    Bent, Paul H.

    1995-01-01

    This report is an evaluation of two techniques for predicting the fan noise radiation from engine nacelles. The first is a relatively computational intensive finite element technique. The code is named ARC, an abbreviation of Acoustic Radiation Code, and was developed by Eversman. This is actually a suite of software that first generates a grid around the nacelle, then solves for the potential flowfield, and finally solves the acoustic radiation problem. The second approach is an analytical technique requiring minimal computational effort. This is termed the cutoff ratio technique and was developed by Rice. Details of the duct geometry, such as the hub-to-tip ratio and Mach number of the flow in the duct, and modal content of the duct noise are required for proper prediction.

  20. Quiet High-Speed Fan

    NASA Technical Reports Server (NTRS)

    Lieber, Lysbeth; Repp, Russ; Weir, Donald S.

    1996-01-01

    A calibration of the acoustic and aerodynamic prediction methods was performed and a baseline fan definition was established and evaluated to support the quiet high speed fan program. A computational fluid dynamic analysis of the NASA QF-12 Fan rotor, using the DAWES flow simulation program was performed to demonstrate and verify the causes of the relatively poor aerodynamic performance observed during the fan test. In addition, the rotor flowfield characteristics were qualitatively compared to the acoustic measurements to identify the key acoustic characteristics of the flow. The V072 turbofan source noise prediction code was used to generate noise predictions for the TFE731-60 fan at three operating conditions and compared to experimental data. V072 results were also used in the Acoustic Radiation Code to generate far field noise for the TFE731-60 nacelle at three speed points for the blade passage tone. A full 3-D viscous flow simulation of the current production TFE731-60 fan rotor was performed with the DAWES flow analysis program. The DAWES analysis was used to estimate the onset of multiple pure tone noise, based on predictions of inlet shock position as a function of the rotor tip speed. Finally, the TFE731-60 fan rotor wake structure predicted by the DAWES program was used to define a redesigned stator with the leading edge configured to minimize the acoustic effects of rotor wake / stator interaction, without appreciably degrading performance.

  1. Noise generated by quiet engine fans. 3: Fan C

    NASA Technical Reports Server (NTRS)

    Montegan, F. J.; Schaefer, J. W.; Schmiedlin, R. F.

    1976-01-01

    A family of fans designed with low noise features was acoustically evaluated, and noise results are documented for a 1.6-pressure-ratio, 472-m/sec (155-ft/sec) tip speed fan. The fan is described and some aerodynamic operating data are given. Far field noise around the fan was measured over a range of operating conditions for a variety of configurations having different arrangements of sound absorbing material in the flow ducts. Complete results of 1.3 octave band analysis of the data are presented in tabular form. Included also are acoustic power spectra and sideline perceived noise levels. Representative 1/3 octave band data are presented graphically, and sample graphs of continuous narrow band spectra are also provided.

  2. 34. VIEW OF SUBMARINE ESCAPE TRAINING TANK PRIOR TO ADDITION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. VIEW OF SUBMARINE ESCAPE TRAINING TANK PRIOR TO ADDITION OF BLISTERS IN 1959, LOOKING SOUTHEAST - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  3. Russian nuclear-powered submarine decommissioning

    SciTech Connect

    Bukharin, O.; Handler, J.

    1995-11-01

    Russia is facing technical, economic and organizational difficulties in dismantling its oversized and unsafe fleet of nuclear powered submarines. The inability of Russia to deal effectively with the submarine decommissioning crisis increases the risk of environmental disaster and may hamper the implementation of the START I and START II treaties. This paper discusses the nuclear fleet support infrastructure, the problems of submarine decommissioning, and recommends international cooperation in addressing these problems.

  4. Saga is largest commercial submarine ever

    SciTech Connect

    Not Available

    1985-05-01

    The long-range autonomous submarine, Saga, went nuclear last year with an agreement between the French and two Canadian companies. The agreement to convert the prototype from Swedish Stirling closed-cycle combustion engines to a nuclear power supply will make Saga the first non-defense nuclear submarine. With an external hull displacement of 500 tons, Saga will be the largest commercial submarine ever built.

  5. Submarine landslides hazard offshore Israel

    NASA Astrophysics Data System (ADS)

    Katz, Oded

    2016-04-01

    Submarine landslides pose significant natural hazards. They can damage seafloor infrastructure, such as that used to recover oil and gas or seafloor telecommunication cables, and even generate tsunamis. We recently mapped 447 submarine landslides across the east Mediterranean continental slope, offshore Israel (hereafter the studied area). The mapped landslides are found at water depths of 130 m to 1,000 m and their volume ranges 10-5 - 100 km3. Landslide scars are typically related to a critical slope angle of >4° . Landslides at the northern part of the studied area are spatially associated with fault scarps and are smaller than the ones on the southern part. In this work we evaluate the potential hazard to population and to on- and off- shore facilities posed by submarine landslides across the studied area. We integrate three independent probabilities: (1) the probability for a landslide event of a given volume, based on the size distribution of the mapped landslides; (2) the probability for a landslide event in a given time, based on the reoccurrence time of triggering earthquakes with M >7, and on a 50,000 years general time frame derived from submarine landslides identified across the Mediterranean Sea; (3) the probability for a landslide event in a given area, based on the distribution of slopes exceeding the critical angle. Overall, the fraction of potentially destructive landslides (size > 0.1 km3) is small, 0.05. Thus, considering typical planning time scales of less than 100 years, the calculated hazard is only moderate. The small fraction of landslides with tsunamogenic potential (size > 1 km3), suggests that the hazard for landslide-induced tsunamis along the open slope part of the studied area is small. Landslides in the southern part of the studied area are larger and thus present a somewhat bigger potential source of tsunami waves.

  6. Turbidite fans in Upper Cretaceous Pierre Shale, Eagle Basin, Colorado: a new reservoir facies

    SciTech Connect

    Krystinik, L.F.

    1983-03-01

    Two fans intercalate with the Upper Cretaceous Pierre Shale and form cliffs over more than 10 mi (16 km) of continuous outcrop in the Eagle basin, north of Walcott, Colorado. Both units exhibit progradational sequences typical of turbidite fans. A common vertical succession of sedimentary structures consists of starved ripples, flat-bottomed ripple beds, thin flat beds grading into ripples of climbing ripples, and amalgamated flat beds. Massive to graded beds are rare and occur only in the upper part of each sandstone body. Associated sedimentary features include parting lineation, grooves, prod marks, mud chips, contorted bedding, and flute casts. Broad, low-relief channels occur at the top of the lower, more well-developed sequence. The sedimentary structures described correlate well with accepted models for turbidite-fan sedimentation. Alternative interpretations of these laterally continuous, progradational sandstone bodies might include deposition in a distal shoreface or offshore bar environment. Hummocky cross-stratification and large-scale cross-stratified bed forms are not common in the sequence, as would be expected in a shoreface or marine-bar environment. Turbidite-fan deposits similar to those studied could be economically significant because of their extreme lateral continuity, updip seals, intercalation with hydrocarbon source rock, and possible overpressuring. The presence of submarine fans within the Cretaceous Western Interior seaway may increase significantly the hydrocarbon potential of previously unexplored, shaly portions of the basin.

  7. Late Quaternary evolution of channel and lobe complexes of Monterey Fan

    USGS Publications Warehouse

    Fildani, A.; Normark, W.R.

    2004-01-01

    The modern Monterey submarine fan, one of the largest deep-water deposits off the western US, is composed of two major turbidite systems: the Neogene Lower Turbidite System (LTS) and the late Quaternary Upper Turbidite System (UTS). The areally extensive LTS is a distal deposit with low-relief, poorly defined channels, overbank, and lower-fan elements. The younger UTS comprises almost half of the total fan volume and was initiated in the late Pleistocene from canyons in the Monterey Bay area. Rapidly prograding high-relief, channel-levee complexes dominated deposition early in the UTS with periodic avulsion events. In the last few 100 ka, much of the sediment bypassed the northern fan as a result of allocyclic controls, and deposition is simultaneously occurring on a sandy lobe with low-relief channels and on an adjacent detached muddier lobe built from reconfinement of overbank flow from the northern high-relief channels. During the relatively short-lived UTS deposition, at least seven different channel types and two lobe types were formed. This study provides a significant reinterpretation of the depositional history of Monterey Fan by incorporating all available unpublished geophysical data. ?? 2004 Elsevier B.V. All rights reserved.

  8. Late Quaternary evolution of channel and lobe complexes of Monterey Fan

    USGS Publications Warehouse

    Fildani, Andrea; Normark, William R.

    2004-01-01

    The modern Monterey submarine fan, one of the largest deep-water deposits off the western US, is composed of two major turbidite systems: the Neogene Lower Turbidite System (LTS) and the late Quarternary Upper Turbidite System (UTS). The areally extensive LTS is a distal deposit with low-relief, poorly defined channels, overbank, and lower-fan elements. The younger UTS comprises almost half of the total fan volume and was initiated in the late Pleistocene from canyons in the Monterey Bay area. Rapidly prograding high-relief, channel-levee complexes dominated deposition early in the UTS with periodic avulsion events. In the last few 100 ka, much of the sediment bypassed the northern fan as a result of allocyclic controls, and deposition is simultaneously occuring on a sandy lobe with low-relief channels and on an adjacent detached muddier lobe built from reconfinement of overbank flow from the northern high-relief channels. During the relatively short-lived UTS deposition, at least seven different channel types and two lobe types were formed. This study provides a significant reinterpretation of the depositional history of Monterey Fan by incorporating all available unpublished geophysical data.

  9. Fan noise research at NASA

    NASA Astrophysics Data System (ADS)

    Groeneweg, John F.

    Results of recent NASA research to reduce aircraft turbofan noise are described. As the bypass ratio of a turbofan engine increases from 5 to as much as 20, the dominant source of engine noise is the fan. A primary mechanism of tone noise generation is the rotor blade wakes interacting with downstream stator vanes. Methods of analyzing rotor-stator tone noise generation are described and sample results are given. The role of an acoustic modal description is emphasized. Wind tunnel tests of model fans and nacelles are described including a novel rotating microphone technique for modal measurement. Sample far field results are given showing the effects of inlet length, and modal measurements are shown which point to a new generation mechanism. Concepts for active fan noise control at the source are addressed. Implications of the research which have general relevance to fan noise generation and control are discussed.

  10. Containment of composite fan blades

    NASA Technical Reports Server (NTRS)

    Coppa, A. P.; Stotler, C. L.

    1977-01-01

    The development of containment concepts for use with large composite fan blades, taking into account the frangible nature of composite blades is considered. Aspects of the development program include; (1) an analysis to predict the interaction between a failed fan blade and the blade containment structure; (2) scaling factors to allow impact testing using subscale containment rings and simulated blades; (3) the design and fabrication of containment systems for further evaluation in a rotating rig test facility; (4) evaluate the test data against the analytically predicted results; and (5) determine overall systems weights and design characteristics of a composite fan stage installation and compare to the requirements of an equivalent titanium fan blade system. Progress in the blade impact penetration tests and the design and fabrication of blade containment systems is reported.

  11. Hydraulic processes on alluvial fans

    SciTech Connect

    French, R.H.

    1987-01-01

    Alluvial fans are among the most prominent landscape features in the American Southwest and throughout the semi-arid and arid regions of the world. The importance of developing a qualitative and quantitative understanding of the hydraulic processes which formed, and which continue to modify, these features derives from their rapid and significant development over the past four decades. As unplanned urban sprawl moved from valley floors onto alluvial fans, the serious damage incurred from infrequent flow events has dramatically increased. This book presents a discussion of our current and rapidly expanding knowledge of hydraulic processes on alluvial fans. It addresses the subject from a multidisciplinary viewpoint, acquainting the reader with geological principles pertinent to the analysis of hydraulic processes on alluvial fans.

  12. Central Fan Integrated Ventilation Systems

    SciTech Connect

    2009-05-12

    This information sheet describes one example of a ventilation system design, a central fan integrated supply (CFIS) system, a mechanical ventilation and pollutant source control to ensure that there is reasonable indoor air quality inside the house.

  13. Fan Noise Research at NASA

    NASA Technical Reports Server (NTRS)

    Groeneweg, John F.

    1994-01-01

    Results of recent NASA research to reduce aircraft turbofan noise are described. As the bypass ratio of a turbofan engine increases from five to as much as 20, the dominant source of engine noise is the fan. A primary mechanism of tone noise generation is the rotor blade wakes interacting with downstream stator vanes. Methods of analyzing rotor stator tone noise generation are described and sample results are given. The role of an acoustic modal description is emphasized. Wind tunnel tests of model fans and nacelles are described including a novel rotating microphone technique for modal measurement. Sample far field results are given showing the effects of inlet length, and modal measurements are shown which point to a new generation mechanism. Concepts for active fan noise control at the source are addressed. Implications of the research which have general relevance to fan noise generation and control are discussed.

  14. Integral fan/water separator

    NASA Technical Reports Server (NTRS)

    Johnson, R. L.

    1976-01-01

    Centrifugal force created by rotating fan wheel separates moisture from gas. Lightweight portable unit can be worn with pressurized suit, where it will remove moisture that accumulates from breathing and perspiration.

  15. Integral fan/water separator

    NASA Technical Reports Server (NTRS)

    Johnson, R. L.

    1976-01-01

    Centrifugal force created by rotating fan wheel separates moisture from gas. Lightweight portable unit can be worn with pressurized suit, where it will remove moisture that accumulates from breathing and perspiration.

  16. PFP supply fan motor starters

    SciTech Connect

    Keck, R.D.

    1995-05-31

    The Plutonium Finishing Plant (PFP) is currently stabilizing about 25 kg of Pu sludge; upon completion of this task, PFP will be maintained in a safe standby condition to await decision from the PFP NEPA review. It can take about 10 years to initiate and complete terminal cleanout after this; the facility will then be decommissioned and decontaminated. The 234-5Z ventilation system must continue to operate until terminal cleanout. Part of the ventilation system is the seismic fan shutdown system which shuts down the ventilation supply fans in case of strong earthquake. This document presents criteria for installing solid state, reduced voltage motor starters and isolation contactors for the 8 main ventilation supply fans. The isolation contactors will shutdown the supply fans in event of earthquake.

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

    NASA Astrophysics Data System (ADS)

    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

  18. Fan/Ram Duct Program

    DTIC Science & Technology

    1973-10-01

    turbofan engine shutoff scheme, the ram duct flow conditions, and the Ian duct shutoff vane area transi- tion schedule. This loss will be...airflow. The performance of the turbofan is neglected until the main engine burner is ignited. At that time it is assumed that the turbo - fan...B. Transient Operation . . .. TRANSIENT TRANSITION TEST CASES A. Turbofan to Ramjet B. Ramjet to Turbo fan CONCLUSIONS AND RECOMMENDATIONS

  19. A Variable Speed Fan Dynamometer

    NASA Technical Reports Server (NTRS)

    Wood, Karl D

    1920-01-01

    Fan brakes used as absorption dynamometers in testing internal combustion engines have the disadvantage that a given fan will run only at one speed when the engine is delivering full power. In order to be able to vary the speed at which a given power will be absorbed, English manufacturers have for some time been using a cylindrical housing around the fan with one or two variable openings in the periphery. Here, results are given of tests conducted to determine how great a range of speed can be obtained from such a device. The tests show that a power ratio of five to 1 can be obtained, the power ratio being defined as the ratio of the power absorbed by the fan at a given speed with the outlet open to the power absorbed at the same speed with the second outlet closed. Data show that improvements in the design of the fan brake can make the speed ratio approach but not exceed a value of two to one. Also given here are a brief outline of previous work on fan brakes, a description of the experimental apparatus and methods used in the tests, and a more detailed statement of test results.

  20. Density as a Cost-driver in Naval Submarine Design and Procurement

    DTIC Science & Technology

    2008-06-25

    eliminating the buoyancy reserve. This satisfies Archimedes ’ Principle , which states that the weight of a displaced fluid is directly proportional to the...because Archimedes ’ Principle requires the densities of all submarines (when submerged) to achieve densities equal to that of water. The primary goal...under very confined conditions; to go further in squeezing up on the contents could become counterproductive and almost certainly push up building costs

  1. Flow structure in submarine meandering channels, a continuous discussion on secondary flow

    NASA Astrophysics Data System (ADS)

    Abad, J. D.; Parker, G.; Sequeiros, O.; Spinewine, B.; Garcia, M. H.; Pirmez, C.

    2011-12-01

    The understanding of the flow structure in deep-sea turbidity currents is important for the formation of submarine meandering channels. Similarly to the case of subaerial channels, several types of secondary flows include turbulence-, curvature- and bed morphodynamic-driven flow structures that modulate sediment transport and channel bed morphodynamics. This study focuses on [1] a review of long-time research effort (Abad et al., 2011) that tackles the description of the secondary flow associated with a subaqueous bottom current (saline) in a high-curvature meandering channel and [2] ongoing numerical simulations of similar settings as the experiments to describe the entire flow structure. In the case of subaerial channels, the classical Rozovskiian paradigm is often invoked which indicates that the near-bottom secondary flow in a bend is directed inward. It has recently been suggested based on experimental and theoretical considerations, however, that this pattern is reversed (near-bottom secondary flow is directed outward) in the case of submarine meandering channels. Experimental results presented here, on the other hand, indicate near-bottom secondary flows that have the same direction as observed in a river (normal secondary flow). The implication is an apparent contradiction between experimental results. This study combines theory, experiments, reconstructions of field flows and ongoing simulations to resolve this apparent contradiction based on the flow densimetric Froude number. Three ranges of densimetric Froude number are found, such that a) in an upper regime, secondary flow is reversed, b) in a middle regime, it is normal and c) in a lower regime, it is reversed. These results are applied to field scale channel-forming turbidity currents in the Amazon submarine canyon-fan system (Amazon Channel) and the Monterey canyon and a saline underflow in the Black Sea flowing from the Bosphorus. Our analysis indicates that secondary flow should be normal

  2. Study on the submarine tracking method of anti-submarine patrol aircraft using passive omni-directional sonobuoys

    NASA Astrophysics Data System (ADS)

    Wang, Xinwei; Wang, Jianguo; Men, Jinzhu

    2017-09-01

    According to submarine tracking problem of the anti-submarine patrol aircraft(ASPA) using passive omnidirectional sonobuoy, the paper discusses on the layout of sonobuoy for tracking submarine, studies on the method of sonobuoy for tracking submarine, and analysis of the whole process of tracking submarine for anti-submarine patrol aircraft using sonobuoys. The papers also take the simulation analysis for 5 kinds of tracking index, and gives out the result as the chart or table, and provides the reference for the research of following submarine for anti submarine patrol aircraft.

  3. Depositional patterns and shelf-margin styles of a lowstand slope fan systems tract, offshore Louisiana

    SciTech Connect

    Bowen, B.E. ); Pacht, J. ); Shaffer, B.L.S.

    1990-05-01

    A complete spectrum of facies from deep-water fans to up-dip deltaics and fluvial sediments occurs in the Pliocene-Pleistocene lowstand fan systems tracts of the Gulf of Mexico. Seismic data, well logs, and biostratigraphy have been used to delineate and map the upper Pliocene slope fan systems tract, commonly referred to as the Lenticulina I interval. This tract contains sands that are major hydrocarbon producers in the southern part of the Louisiana shelf. Both a ramp margin and a growth fault modified ramp margin can be recognized in this unit. Large submarine fans with well-developed channel levee complexes occur basinward of the growth fault margin. The sands in these sediments typically are thin-bedded and highly lenticular. On the upside of the growth faults, the slope fan sediments can be chronostratigraphically correlated to deltaics by using the encasing condensed sections that have been defined by biostratigraphy. The sands in the deltaics are coarsening-upward cycles, occasionally blocky, are generally thicker bedded than the downdip fan deposits. Updip, the semicontinuous to continuous reflectors of the deltaic sediments are replaced by highly discontinuous reflectors with variable amplitude characteristic of upper delta plain or fluvial deposits. A different set of facies is characteristic of the ramp margin. Extensive slope fan sediments are rarely developed and the updip deltaic wedge tends to be thicker and is characterized by slumping along the seaward margin. The deltaics occur in an area that extends about 100 mi along strike and 75 mi in the dip direction.

  4. Flow performance of highly loaded axial fan with bowed rotor blades

    NASA Astrophysics Data System (ADS)

    Chen, L.; Liu, X. J.; Yang, A. L.; Dai, R.

    2013-12-01

    In this paper, a partial bowed rotor blade was proposed for a newly designed high loaded axial fan. The blade was positively bowed 30 degrees from hub to 30 percent spanwise position. Flows of radial blade and bowed blade fans were numerically compared for various operation conditions. Results show that the fan's performance is improved. At the designed condition with flow coefficient of 0.52, the efficiency of the bowed blade fan is increased 1.44% and the static pressure rise is increased 11%. Comparing the flow structures, it can be found that the separated flow in the bowed fan is reduced and confined within 20 percent span, which is less than the 35 percent in the radial fan. It means that the bowed blade generates negative blade force and counteracts partial centrifugal force. It is alleviates the radial movements of boundary layers in fan's hub region. Flow losses due to 3D mixing are reduced in the rotor. Inlet flow to downstream stator is also improved.

  5. Reference PMHS Sled Tests to Assess Submarining.

    PubMed

    Uriot, Jérôme; Potier, Pascal; Baudrit, Pascal; Trosseille, Xavier; Petit, Philippe; Richard, Olivier; Compigne, Sabine; Masuda, Mitsutoshi; Douard, Richard

    2015-11-01

    Sled tests focused on pelvis behavior and submarining can be found in the literature. However, they were performed either with rigid seats or with commercial seats. The objective of this study was to get reference tests to assess the submarining ability of dummies in more realistic conditions than on rigid seat, but still in a repeatable and reproducible setup. For this purpose, a semi-rigid seat was developed, which mimics the behavior of real seats, although it is made of rigid plates and springs that are easy to reproduce and simulate with an FE model. In total, eight PMHS sled tests were performed on this semirigid seat to get data in two different configurations: first in a front seat configuration that was designed to prevent submarining, then in a rear seat configuration with adjusted spring stiffness to generate submarining. All subjects sustained extensive rib fractures from the shoulder belt loading. No pelvis fractures and no submarining were observed in the front seat configuration, but two subjects sustained lumbar vertebrae fractures. In the rear seat configuration, all subjects sustained pelvic fractures and demonstrated submarining. Corridors were constructed for the external forces and the PMHS kinematics. They are provided in this paper as new reference tests to assess the biofidelity of human surrogates in different configurations that either result in submarining or do not. In future, it is intended to analyze further seat and restraint system configurations to be able to define a submarining predictor.

  6. Obsolescence Management for Virginia-Class Submarines

    DTIC Science & Technology

    2010-10-01

    century. PROBLEM Although the Vitginia- chss submarine is designed for maximum flexibility, allowing tor technological insertion and innovation over the... chss obsoles- cence program was the submarine’s design using modules, open architecture, and COTS compo- nents. The following are the key lessons

  7. Comparative Naval Architecture Analysis of Diesel Submarines

    DTIC Science & Technology

    2005-06-01

    mission, cost, or other factors affect the architecture? This study examines and compares the naval architecture of selected diesel submarines from...79 A ppendix E : Subm arine Shape Factors ................................................................................... 90 5 List of...country. Do factors such as mission, cost, or tradition 10 affect submarine naval architecture? An in depth comparison is performed of six diesel

  8. Nuclear Submarines and Aircraft Carriers | Radiation ...

    EPA Pesticide Factsheets

    2017-08-07

    Nuclear submarines and aircraft carriers are powered by onboard nuclear reactors. Heat from the nuclear reaction makes the steam needed to power the submarine. When a nuclear vessel is taken out of service, its radioactive parts are disposed of and monitored.

  9. Two-Stage Centrifugal Fan

    NASA Technical Reports Server (NTRS)

    Converse, David

    2011-01-01

    Fan designs are often constrained by envelope, rotational speed, weight, and power. Aerodynamic performance and motor electrical performance are heavily influenced by rotational speed. The fan used in this work is at a practical limit for rotational speed due to motor performance characteristics, and there is no more space available in the packaging for a larger fan. The pressure rise requirements keep growing. The way to ordinarily accommodate a higher DP is to spin faster or grow the fan rotor diameter. The invention is to put two radially oriented stages on a single disk. Flow enters the first stage from the center; energy is imparted to the flow in the first stage blades, the flow is redirected some amount opposite to the direction of rotation in the fixed stators, and more energy is imparted to the flow in the second- stage blades. Without increasing either rotational speed or disk diameter, it is believed that as much as 50 percent more DP can be achieved with this design than with an ordinary, single-stage centrifugal design. This invention is useful primarily for fans having relatively low flow rates with relatively high pressure rise requirements.

  10. Currents in monterey submarine canyon

    USGS Publications Warehouse

    Xu, J. P.; Noble, M.A.

    2009-01-01

    Flow fields of mean, subtidal, and tidal frequencies between 250 and 3300 m water depths in Monterey Submarine Canyon are examined using current measurements obtained in three yearlong field experiments. Spatial variations in flow fields are mainly controlled by the topography (shape and width) of the canyon. The mean currents flow upcanyon in the offshore reaches (>1000 m) and downcanyon in the shallow reaches (100-m amplitude isotherm oscillations and associated high-speed rectilinear currents. The 15-day spring-neap cycle and a ???3-day??? band are the two prominent frequencies in subtidal flow field. Neither of them seems directly correlated with the spring-neap cycle of the sea level.

  11. Cardiovascular Risk Factors in Submariners

    DTIC Science & Technology

    1979-01-01

    submariners. Skinfold thickness in these subjects was determined to be higher than in most other groups of men of similar age; the total level of body...infrascapular) regions indicated a considerable excess of skinfold thickness in the subjects of this study compared to other population groups. While...mean values of 1.69, 1.84, and 2.19 cm for infra- scapular skinfotds and 1.07, 1.13, and 1.27 cm for triceps skinfolds using the Harpenden , Lange

  12. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  13. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  14. 29. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION AT POINT JUST ABOVE THE SUBMARINE SECTION AT THE 110-FOOT LEVEL 1929-1930 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  15. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  16. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 5 2012-07-01 2012-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine... submarines....

  17. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  18. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 5 2013-07-01 2013-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine... submarines....

  19. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 5 2014-07-01 2014-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine... submarines....

  20. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 5 2011-07-01 2011-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine... submarines....

  1. 32. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONN. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONN. OCTOBER 3, 1932. COMPLETION OF ERECTION OF STEELWORK FOR ELEVATOR. LOOKING NORTH. CONTRACT NO. Y-1539-ELEVATOR, SUBMARINE ESCAPE TANK.' - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  2. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine... submarines....

  3. Fan Flutter Analysis Capability Enhanced

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Srivastava, Rakesh; Stefko, George L.

    2001-01-01

    The trend in the design of advanced transonic fans for aircraft engines has been toward the use of complex high-aspect-ratio blade geometries with a larger number of blades and higher loading. In addition, integrally bladed disks or blisks are being considered in fan designs for their potential to reduce manufacturing costs, weight, and complexity by eliminating attachments. With such design trends, there is an increased possibility within the operating region of part-speed stall flutter (self-excited vibrations) that is exacerbated by the reduced structural damping of blisk fans. To verify the aeroelastic soundness of the design, the NASA Glenn Research Center is developing and validating an accurate aeroelastic prediction and analysis capability. Recently, this capability was enhanced significantly as described here.

  4. Heavy mineral assemblages in Lower-Middle Miocene sediments in the Bengal Fan, IODP Exp. 354

    NASA Astrophysics Data System (ADS)

    Yoshida, K.; Cruz, J. W.; Gyawali, B. R.; Osaki, A.; Manoj, M. C.; Hatano, N.; France-Lanord, C.; Spiess, V.; Klaus, A.

    2016-12-01

    The submarine Bengal Fan is the largest submarine fan system on Earth. The formation of this fan is a direct result of the India-Asia plate collision. Thus, changes in the mineral assemblages of fan sediments record the uplift history of the Himalayan orogenic system. IODP Expedition 354 drilled seven sites in an E-W transect along the 8°N latitude in the Bengal Fan. The deepest site U1451, 1200 m below the seafloor, recovered a complete sequence of fan deposits. The sediments drilled at this site consisted of mica- and quartz-rich sand, silt, and clay, with the exception of the lower Oligocene-Eocene section. In this study, we present preliminary results of the modal proportions of heavy minerals in the sediments recovered from Site U1451 using thin sections with EDS analysis, and discuss the historical changes of the mineral assemblages. The heavy mineral assemblage of the Late Oligocene silt-sands, to which the oldest sediments of the Bengal Fan belong, mainly consists of tourmaline and rutile assemblage with rare garnet and amphibole. The heavy mineral assemblage in the Early Miocene sediments mainly includes a ZTR (zircon-tourmaline-rutile) component with small amounts of garnet, apatite, aluminosilicates (kyanite and sillimanite) and staurolite. At the early part of the Middle Miocene sequence, amphibole and garnets increase rapidly, and there are frequent occurrences of aluminosilicate and staurolite. In the Middle Miocene sediments, the assemblage of heavy minerals becomes diverse, and metamorphic minerals, such as staurolite, chloritoid, aluminosilicate (kyanite and sillimanite), amphibole, and garnet, are normally included in the sediments. These measurements of heavy minerals demonstrate wide exposure and sediment production from a metamorphic terrane in the Himalayas during the Middle Miocene period, though these high-grade metamorphic minerals are occasionally included in Early Miocene sands. Also the above mentioned metamorphic mineral grains of

  5. Vacuum Cleaner Fan Being Improved

    NASA Technical Reports Server (NTRS)

    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.

  6. 30 CFR 75.302 - Main mine fans.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ventilated by one or more main mine fans. Booster fans shall not be installed underground to assist main mine fans except in anthracite mines. In anthracite mines, booster fans installed in the main air current or...

  7. Sound maintenance practices protect fan investments

    SciTech Connect

    Bauer, M.

    2009-11-15

    Since underground coal miners depend on axial fans, lack of maintenance could prove costly. A number of pre-emptive actions that can help keep fans running at optimal performance can also be taken. 2 photos.

  8. Stratigraphy of Alluvial Fans in Saheki Crater

    NASA Image and Video Library

    2016-03-23

    Alluvial fans are gently-sloping wedges of sediments deposited by flowing water. Some of the best-preserved alluvial fans on Mars are in Saheki Crater, seen here by NASA Mars Reconnaissance Orbiter spacecraft.

  9. Prop-fan with improved stability

    NASA Technical Reports Server (NTRS)

    Rothman, Edward A. (Inventor); Violette, John A. (Inventor)

    1988-01-01

    Improved prop-fan stability is achieved by providing each blade of the prop-fan with a leading edge which, outwardly, from a location thereon at the mid-span of the blade, occupy generally a single plane.

  10. Global estimates of fresh submarine groundwater discharge

    NASA Astrophysics Data System (ADS)

    Luijendijk, Elco; Gleeson, Tom; Moosdorf, Nils

    2016-04-01

    Fresh submarine groundwater discharge, the flow of fresh groundwater to oceans, may be a significant contributor to the water and chemical budgets of the world's oceans. We present new estimates of the flux of fresh groundwater to the world's oceans. We couple density-dependent numerical simulations of generic models of coastal basins with geospatial databases of hydrogeological parameters and topography to resolve the rate of terrestrially-derived submarine groundwater discharge globally. We compare the model results to a new global compilation of submarine groundwater discharge observations. The results show that terrestrially-derived SGD is highly sensitive to permeability. In most watersheds only a small fraction of groundwater recharge contributes to submarine groundwater discharge, with most recharge instead contributing to terrestrial discharge in the form of baseflow or evapotranspiration. Fresh submarine groundwater discharge is only significant in watersheds that contain highly permeable sediments, such as coarse-grained siliciclastic sediments, karstic carbonates or volcanic deposits. Our estimates of global submarine groundwater discharge are much lower than most previous estimates. However, many tropical and volcanic islands are hotspots of submarine groundwater discharge and solute fluxes towards the oceans. The comparison of model results and data highlights the spatial variability of SGD and the difficulty of scaling up observations.

  11. Naval submarine base Kings Bay and Bangor soil evaluations.

    SciTech Connect

    Holcomb, David Joseph; Patteson, Raymond; Wesenberg, Donald L.; Attaway, Stephen W.

    2004-08-01

    This report provides soil evaluation and characterization testing for the submarine bases at Kings Bay, Georgia, and Bangor, Washington, using triaxial testing at high confining pressures with different moisture contents. In general, the samples from the Bangor and Kings Bay sites appeared to be stronger than a previously used reference soil. Assuming the samples of the material were representative of the material found at the sites, they should be adequate for use in the planned construction. Since soils can vary greatly over even a small site, a soil specification for the construction contractor would be needed to insure that soil variations found at the site would meet or exceed the requirements. A suggested specification for the Bangor and Kings Bay soils was presented based on information gathered from references plus data obtained from this study, which could be used as a basis for design by the construction contractor.

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

    NASA Technical Reports Server (NTRS)

    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.

  13. Review of Aircraft Engine Fan Noise Reduction

    NASA Technical Reports Server (NTRS)

    VanZante, Dale

    2008-01-01

    Aircraft turbofan engines incorporate multiple technologies to enhance performance and durability while reducing noise emissions. Both careful aerodynamic design of the fan and proper installation of the fan into the system are requirements for achieving the performance and acoustic objectives. The design and installation characteristics of high performance aircraft engine fans will be discussed along with some lessons learned that may be applicable to spaceflight fan applications.

  14. Sequence stratigraphy, facies architecture and reservoir distribution, Cretaceous lowstand fan reservoirs, Southern Basin, onshore Trinidad

    SciTech Connect

    Sprague, A.R.; Larue, D.K.; Faulkner, B.L.

    1996-08-01

    Thick Albian-Campanian mass-flow sandstones in the Southern Basin Trinidad were deposited within submarine canyons incised into the northern continental slope of South America and as associated down-dip basin-floor lowstand fans. The contemporaneous slope to basin-floor break lay across the Southern Basin area with turbidity current paleoflow being to the northwest. North of this paleo-slope break graded to massive, channelized, high-density turbidite sandstones occur interstratified with shaly overbank and channel abandonment deposits. A progression of depositional sub-environments from proximal through distal lowstand fan can be recognized. All fine and thin upward but can be discriminated by the occurrence of slumps, debris flows and conglomerates, the grain-size and bedding scale of sandstones and the characteristics of low-density turbidites and mudrocks. South of the paleo-slope break mass-flow deposits comprise muddy slumps and debris flows rich in granules and pebbles deposited in slope canyons. During periods of turbidity current by-pass or fan abandonment hemipelagic settling processes predominated. Reservoir distribution maps of these lowstand fans have been constructed utilizing geometric constraints, analogs and paleoslope determinations from oriented core. The interpreted canyon locations and orientations are key to the understanding of reservoir distribution on the basin-floor tract to the north: a vital component in the exploration of the basin.

  15. Section Selection Software Design for Submarine Cables

    NASA Astrophysics Data System (ADS)

    Li, Meng; Niu, Sheng-suo; Song, Yan; Jia, Xu-ce; Liu, Yu-qin; Zhao, Ke-wei

    2017-08-01

    In order to improve the efficiency and accuracy of ampacity calculation and submarine cable’s section selection, this article improved the shortage of IEC(International Electrotechnical Commission) norms when calculating the ampacity of submarine cables, developed hierarchical principles and established accurate thermal circuit model of the various types of cables. This article realized accurate calculation of ampacity and achieved the ampacity calculation software module’s design. Finally this article firstly developed a section selection software for submarine cables combined with the heat-stable calibration module. After verified the accuracy and effectiveness of software in the typical layout conditions, this software can provide good guidance for practical engineering.

  16. Online Fan Fiction and Critical Media Literacy

    ERIC Educational Resources Information Center

    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…

  17. 14 CFR 29.908 - Cooling fans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant General § 29.908 Cooling fans. For cooling fans that are... in Category A rotorcraft, it must be shown that a fan blade failure will not prevent continued safe flight either because of damage caused by the failed blade or loss of cooling air. (b) Category B....

  18. 14 CFR 29.908 - Cooling fans.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant General § 29.908 Cooling fans. For cooling fans that are... in Category A rotorcraft, it must be shown that a fan blade failure will not prevent continued safe flight either because of damage caused by the failed blade or loss of cooling air. (b) Category B....

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

    USGS Publications Warehouse

    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

  20. School Athletics and Fan Aggression

    ERIC Educational Resources Information Center

    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…

  1. Flow Over a Model Submarine

    NASA Astrophysics Data System (ADS)

    Jiménez, Juan; Smits, Alexander

    2003-11-01

    Experimental investigation over a DARPA SUBOFF submarine model (SUBOFF Model) was performed using flow visualization and Digital Particle Image Velocimetry (DPIV). The model has an axisymmetric body with sail and fins, and it was supported by a streamlined strut that was formed by the extension of the sail appendage. The range of flow conditions studied correspond to a Reynolds numbers based on model length, Re_L, of about 10^5. Velocity vector fields, turbulence intensities, vorticity fields, and flow visualization in the vicinity of the junction flows are presented. In the vicinity of the control surface and sail hull junctions, the presence of streamwise vortices in the form of horseshoe or necklace vortices locally dominates the flow. The effects of unsteady motions about an axis passing through the sail are also investigated to understand the evolution of the unsteady wake.

  2. Fan-in-Fuselage Advanced Antitorque System

    DTIC Science & Technology

    1974-11-01

    EFFECTS IN AXIAL FLOW FANS, Air - craft Engineering, Vol. XXXIII No. 393, November 1961, pp. 314-319 29. Wahl, H. A., et al, DUCTED FAN DESIGN STUDY OF THE...sl/sec) V. = air flow velocity at fan, ft/sec V = outlet (jet) velocity, ft/sec A. = cross-sectiondl area at fan, sq ft A = cross-sectional...loading), of low flow - through velocities, and of a small tip clearance are all highly desirable. Fan power for a given rotor power thus varies

  3. CHALLENGES POSED BY RETIRED RUSSIAN NUCLEAR SUBMARINES

    SciTech Connect

    Rudolph, Dieter; Kroken, Ingjerd; Latyshev, Eduard; Griffith, Andrew

    2003-02-27

    The purpose of this paper is to provide an overview of the challenges posed by retired Russian nuclear submarines, review current U.S. and International efforts and provide an assessment of the success of these efforts.

  4. Personality and coping strategies during submarine missions.

    PubMed

    Sandal, Gro M; Endresen, Inger M; Vaernes, Ragnar; Ursin, Holger

    2003-01-01

    Relations between personality profiles, measured by the Personality Characteristics Inventory (PCI), and habitual coping strategies, measured by the Utrecht Coping List (UCL), were investigated in a sample of submarine personnel and office employees. The predictive validity of these instruments were examined for reported stress, health complaints, and salivary cortisone measures during 3 submarine missions. PCI and UCL were completed before the missions, and questionnaires and saliva were collected weekly. The results showed no significant relations between PCI profiles and coping strategies. Interpersonal orientation, achievement motivation, and habitual coping strategies were predictors for coping during the submarine missions. Problem-directed strategies and interpersonal sensitivity combined with strong achievement motivation were related to low indicated stress from social factors (lack of privacy, interpersonal tension, and crowding) and homesickness. The findings suggest that interpersonal characteristics need to be considered in the selection of submariners and personnel for other military settings in which units are exposed to prolonged stress and isolation.

  5. Personality and coping strategies during submarine missions.

    PubMed

    Sandal, G M; Endresen, I M; Vaernes, R; Ursin, H

    1999-01-01

    Relations between personality profiles, measured by the Personality Characteristics Inventory (PCI), and habitual coping strategies, measured by the Utrecht Coping List (UCL), were investigated in a sample of submarine personnel and office employees. The predictive validity of these instruments were examined for reported stress, health complaints, and salivary cortisone measures during 3 submarine missions. PCI and UCL were completed before the missions, and questionnaires and saliva were collected weekly. The results showed no significant relations between PCI profiles and coping strategies. Interpersonal orientation, achievement motivation, and habitual coping strategies were predictors for coping during the submarine missions. Problem-directed strategies and interpersonal sensitivity combined with strong achievement motivation were related to low indicated stress from social factors (lack of privacy, interpersonal tension, and crowding) and homesickness. The findings suggest that interpersonal characteristics need to be considered in the selection of submariners and personnel for other military settings in which units are exposed to prolonged stress and isolation.

  6. Decision Making in the Submarine Information Architecture

    DTIC Science & Technology

    2012-12-15

    submarine’s resources across time and operational geography to produce the output that the higher level plan requires. There are opportunities to...the intended track of the submarine in geography and in time. This is executed through use of a U.S. Navy approved Electronic Chart Display and...Spring( 42). Hoverstadt, P. (2008) The Fractal Organization: Creating Sustainable Organizations with the Viable Systems Model. West Sussex, UK: Wiley

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

    USGS Publications Warehouse

    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.

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

    PubMed

    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.

  9. Sedimentologic evolution of a submarine canyon in a forearc basin, Upper Cretaceous Rosario Formation, San Carlos, Mexico

    SciTech Connect

    Morris, W.R.; Busby-Spera, C.J.

    1988-06-01

    The walls, floor, and fill of a submarine canyon are well-exposed near San Carlos, Mexico, in forecarc strata of the Upper Cretaceous Rosario Formation. The submarine canyon is about 7 km wide and at least 230 m deep and has eroded a minimum of 150 m into underlying fluvial red beds. It is unclear whether subaerial or submarine processes initiated the canyon cutting; however, marine processes, especially debris flows, modified the morphology of the submarine canyon. The submarine canyon fill and overlying slope deposits form two major fining-upward sequences. The first includes a 120 m thick lower conglomerate-sandstone unit (LCSU) at the base of the canyon fill overlain by a 50-110 m thick middle mudstone-sandstone unit (MMSU). The MMSU consists predominantly of mudstone and thin-bedded sandstone, but includes a channel filled with sandstone beds that form a fining- and thinning-upward sequence. This sequence is overlain by the second major sequence, a 0-60 m thick upper conglomerate-sandstone unit (UCSU), which is confined to three channels within the submarine canyon and passes gradationally upward into slope mudstone. Each of the two major fining-upward sequences records a gradual decrease in supply of coarse-grained sediment to the submarine canyon head. The first fining-upward sequence may correspond to a lowstand and subsequent rise in global sea level or, alternatively, may have resulted from local downdropping of the basin. The second fining-upward sequence does not correspond to global sea level fluctuations but is age-correlative with a drop then rise in relative sea level recognized by other workers 300-400 km to the north in the San Diego-Ensenada area. This sea level drop is inferred to have been a regional-scale tectonic event that affect the forearc basin along its length. 18 figures, 2 tables.

  10. Low Noise Research Fan Stage Design

    NASA Technical Reports Server (NTRS)

    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.

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

    USGS Publications Warehouse

    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.

  12. Reconstructing the formation mechanism of submarine biogenic stalactites: The contribution of AMS

    NASA Astrophysics Data System (ADS)

    Quarta, G.; D'Elia, M.; Calcagnile, L.; Belmonte, G.; Ingrosso, G.

    2010-04-01

    Submarine caves at the Cape of Otranto in South-Eastern Italy host eccentric stalactites which have been recently recognised as completely biogenic. The possibility to use the calcareous tubules of Polichaete forming the inner texture of the stalactites as suitable samples for radiocarbon dating is described. AMS radiocarbon dating analyses performed on samples taken at different positions along the longitudinal axis of three different stalactites allowed to obtain information about the duration of the formation phase, to determine the growth-rate at different stages of evolution and to establish the complete submarine origin of the stalactites. The comparison of the radiocarbon data obtained for the different studied structures reveal also similarities as well as important differences between single stalactites, supplying new information about their response to environmental changes in the same, confined ecosystem.

  13. Human-Powered Submarine Competition: World Submarine International 1996 [and] Design Technology Exhibit: A School Model.

    ERIC Educational Resources Information Center

    Hibberd, John C.; Edwards, Don

    1996-01-01

    Hibbard describes the process used by students at Millersville University to build a human-powered submarine for entry in an international submarine competition. Edwards discusses the Design Technology Exhibit held at Lu Sutton Elementary School, the purpose of which was to challenge students to design a useful structure and provide them with the…

  14. Flutter of swept fan blades

    NASA Technical Reports Server (NTRS)

    Kielb, R. E.; Kaza, K. R. V.

    1984-01-01

    The effect of sweep on fan blade flutter is studied by applying the analytical methods developed for aeroelastic analysis of advance turboprops. Two methods are used. The first method utilizes an approximate structural model in which the blade is represented by a swept, nonuniform beam. The second method utilizes a finite element technique to conduct modal flutter analysis. For both methods the unsteady aerodynamic loads are calculated using two dimensional cascade theories which are modified to account for sweep. An advanced fan stage is analyzed with 0, 15 and 30 degrees of sweep. It is shown that sweep has a beneficial effect on predominantly torsional flutter and a detrimental effect on predominantly bending flutter. This detrimental effect is shown to be significantly destabilizing for 30 degrees of sweep.

  15. Seismic characteristics, morphology and formation of the ponded Fangliao Fan off southwestern Taiwan, northern South China Sea

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    Using bathymetry and reflection seismic profiles this study reveals the nature of the modern ponded Fangliao Fan within a framework of sediment infilling of an intra-slope basin on a tectonically active margin off southwestern Taiwan. The Fangliao Fan begins at the mouth of Fangliao Canyon at a water depth of 900 m and terminates down-slope at the escarpment of a linear ridge north of the Kaoping Slope Valley at a water depth of about 1,100 m, sediment gravity flows being prevented from farther down-slope transport due to ponding against this bathymetric high. The fan appears as a distinct basinward-opening triangular depocenter confined by ridges on both sides and the NW-SE trending ridge aligned normal to the elongation of the fan. These topographic ridges were formed by mud-diapiric intrusions. The external form of the ponded Fangliao Fan is characterized by a fan-valley fill pattern that has a concave cross-sectional morphology, in contrast to typical mounded fans deposited on slope-basin plains having a smooth topography. Sediment episodically funneled through the Fangliao Canyon from upslope areas and derived from the flanks of the mud-diapiric ridges are mainly transported by mass movement before being re-dispersed by unconfined channels to infill the intra-slope basin, thereby building up channelized fan complexes with poorly developed levees. The sediment flows from the mouth of Fangliao Canyon flow down-slope along the west flank of the Fangliao Ridge. In the process, a feeder channel has been eroded into the seafloor along which sediment is transported to the distal parts of the fan. Sediment west of the feeder channel is mainly redistributed by mass movement and/or fan channels to fill up the irregular topographic low in the slope. Due to a very low sediment supply, Fangliao Fan represents a starved ponded slope fan. As such it provides insights into the processes by which ponded fans develop and can therefore serve as an analog for similar fans

  16. High Bypass Turbofan Component Development. Amendment I. Small Fan Redesign.

    DTIC Science & Technology

    1980-02-01

    to Original Hub Section 22 15. Fan Rotor Load Distribution 23 16. Fan Disk Stress Model 24 17. Redesigned Fan Blisk 3/4 View 25 18. Comparison of...Initial & Redesigned Fan Blisk - Front View 26 19. Comparison of Initial & Redesigned Fan Blisk - Rear View 27 20. Comparison of Initial & Redesigned Fan ... blisk are covered by this Contract. -2- DESCRIPTIOH OF TECHNICRL WORK FAN ROTOR AERODYNAMIC DESIGN Method of Characteristics It is well known that the

  17. Submarine fan reservoir architecture and heterogeneity influence on hard-to-recover reserves. Achimov Fm

    NASA Astrophysics Data System (ADS)

    Kondratyev, A.; Rukavishnikov, V.; Shakirzyanov, L.; Maksyutin, K.

    2015-02-01

    Due to the fact that simulation model calculation is the basic method used for estimating the efficiency of a development strategy, it is necessary to design geological and simulation models within which reservoir properties and heterogeneity are defined. In addition, the estimation of the influence of various kinds of geological uncertainties on reservoir properties will allow defining a more effective development strategy. The Achimov formation of the Vingapur oil field was considered in the current study. The northern part of the field is now quite attractive for the development of this formation. The goal of this paper was the complex investigation of petrophysical properties to make a prognosis for the field and assess the effect of geologic uncertainties on production. The first step implied studying the western part of the field where core data are available, the next stage was developing an algorithm to make a prognosis for properties and the geologic and reservoir simulation models were eventually constructed to study the effect of geologic uncertainties in the northern part. As the result of the sedimentary analysis, a model of deposition was defined within which structural elements were also determined. On the basis of wireline and core data analysis, the petrophysical model of the reservoir was build where the method of Rock Types identification using specific cut-off values for wireline logs was applied for the evaluations. In addition to this, the Hydraulic Flow unit approach was employed, which allowed estimating the less extensively explored areas of the field where core had not been retrieved from. Also, this paper provides the results of the seismic attribute analysis and calculations in order to characterize uncertainty in cumulative oil production under the influence of petrophysical and geological heterogeneity.

  18. Deep-sea channel/submarine-yazoo system of the Labrador Sea: A new deep-water facies model

    SciTech Connect

    Hesse, R.; Rakofsky, A. )

    1992-05-01

    The deep-sea channel/submarine-yazoo system is a newly recognized deep-water depositional environment that is significantly different from previously documented turbidite environments. The new system is in many ways the antithesis of classical deep-sea fans. The purpose of this paper is to present the characteristics and elements of the system, develop a facies model for it, establish the system variables, and discuss its possible significance in the geologic record and in subsurface exploration. Previous investigators of deepwater turbidite sediments often faced difficulties in trying to fit their sequences into traditional single-source, deep-sea fan models. The present model fills part of an obvious gap in interpretation schemes for deep-water clastic sediments.

  19. Sediment dispersal pattern in the Bay of Bengal - evidence for commencement of Bengal Fan sedimentation

    NASA Astrophysics Data System (ADS)

    Krishna, K. S.; Ismaiel, M.; Karlapati, S.; Gopala Rao, D.; Mishra, J.; D, S.

    2015-12-01

    The sediment succession in the Bay of Bengal records signatures corresponding to India-Asia collision, regional climate, and erosional processes of the Himalayan orogeny and the Indian subcontinent. The Bengal Fan - world's largest submarine fan - has been long studied to understand the link between the Himalayan tectonics and Asian monsoon climate, but early phase information of the Himalaya erosion is not retrieved from the Indian Ocean due to lack of deep-core samples. Therefore, the missing corresponding signals hampered the understanding of coupled processes between tectonics, climate and erosion. Seismic reflection profiles and industrial drill wells from the western Bay of Bengal show two different modes of sediment deposition: initially Indian peninsular rivers discharged sediments to the ocean at a rate ~20 m/m.y. until Oligocene-Miocene time (~23 Ma) with the exception of two fairly-enhanced sediment pulses from 65 to 54 and again from 34 to 23 Ma; since 23 Ma the Ganges and Brahmaputra rivers added huge volumes of sediments to the bay with variable rates range from 40 to >1000 m/m.y. Using seismic stratigraphic technique we found a distinct increase in sediment discharge (~140 m/m.y.) at 23 Ma is an important age marker for the onset of Bengal Fan sedimentation as a coupled connection between the Himalayan tectonics and Asian climate. Further rise in sedimentation rate during the period 6.8 - 0.8 Ma is surprisingly not in agreement with the decrease in sediment rate reported at ODP Leg 116 sites in the distal Bengal Fan, but coincident with the change in monsoon intensity. Here we provide well constrained ages for the growth of the Bengal Fan, which can serve as benchmark for interactions between the Himalayan exhumation and Asian climate.

  20. Highstand fans in the California borderland: the overlooked deep-water depositional systems

    USGS Publications Warehouse

    Covault, Jacob A.; Normark, William R.; Romans, Brian W.; Graham, Stephan A.

    2007-01-01

    Contrary to widely used sequence-stratigraphic models, lowstand fans are only part of the turbidite depositional record; our analysis reveals that a comparable volume of coarse-grained sediment has been deposited in California borderland deep-water basins regardless of sea level. Sedimentation rates and periods of active sediment transport have been determined for deep-water canyon-channel systems contributing to the southeastern Gulf of Santa Catalina and San Diego Trough since 40 ka using an extensive grid of high-resolution and deep-penetration seismic-reflection data. A regional seismic-reflection horizon (40 ka) has been correlated across the study area using radiocarbon age dates from the Mohole borehole and U.S. Geological Survey piston cores. This study focused on the submarine fans fed by the Oceanside, Carlsbad, and La Jolla Canyons, all of which head within the length of the Ocean-side littoral cell. The Oceanside Canyon–channel system was active from 45 to 13 ka, and the Carlsbad system was active from 50 (or earlier) to 10 ka. The La Jolla system was active over two periods, from 50 (or earlier) to 40 ka, and from 13 ka to the present. One or more of these canyon-channel systems have been active regardless of sea level. During sea-level fluctuation, shelf width between the canyon head and the littoral zone is the primary control on canyon-channel system activity. Highstand fan deposition occurs when a majority of the sediment within the Oceanside littoral cell is intercepted by one of the canyon heads, currently La Jolla Canyon. Since 40 ka, the sedimentation rate on the La Jolla highstand fan has been >2 times the combined rates on the Oceanside and Carlsbad lowstand fans.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    -Baltimore, Norfolk-Washington, and Hatteras) are being investigated from the canyon heads down to their deep-water submarine fans in an effort to characterize their sediment transport history and constrain the influences of external processes on their morphology. Each canyon-fan system is morphologically unique and is strongly controlled by source region, antecedent margin morphology, landslide and debris flow processes, and the long-term influence of deep-water (along-slope) currents.

  2. Hydroplaning and submarine debris flows

    NASA Astrophysics Data System (ADS)

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

    2004-01-01

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

  3. Acoustic Power Transmission Through a Ducted Fan

    NASA Technical Reports Server (NTRS)

    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.

  4. Laboratory alluvial fans in one dimension.

    PubMed

    Guerit, L; Métivier, F; Devauchelle, O; Lajeunesse, E; Barrier, L

    2014-08-01

    When they reach a flat plain, rivers often deposit their sediment load into a cone-shaped structure called alluvial fan. We present a simplified experimental setup that reproduces, in one dimension, basic features of alluvial fans. A mixture of water and glycerol transports and deposits glass beads between two transparent panels separated by a narrow gap. As the beads, which mimic natural sediments, get deposited in this gap, they form an almost one-dimensional fan. At a moderate sediment discharge, the fan grows quasistatically and maintains its slope just above the threshold for sediment transport. The water discharge determines this critical slope. At leading order, the sediment discharge only controls the velocity at which the fan grows. A more detailed analysis reveals a slight curvature of the fan profile, which relates directly to the rate at which sediments are transported.

  5. Mathematical modelling of submarine landslide motion

    NASA Astrophysics Data System (ADS)

    Burminskij, A.

    2012-04-01

    Mathematical modelling of submarine landslide motion The paper presents a mathematical model to calculate dynamic parameters of a submarine landslide. The problem of estimation possible submarine landslides dynamic parameters and run-out distances as well as their effect on submarine structures becomes more and more actual because they can have significant impacts on infrastructure such as the rupture of submarine cables and pipelines, damage to offshore drilling platforms, cause a tsunami. In this paper a landslide is considered as a viscoplastic flow and is described by continuum mechanics equations, averaged over the flow depth. The model takes into account friction at the bottom and at the landslide-water boundary, as well as the involvement of bottom material in motion. A software was created and series of test calculations were performed. Calculations permitted to estimate the contribution of various model coefficients and initial conditions. Motion down inclined bottom was studied both for constant and variable slope angle. Examples of typical distributions of the flow velocity, thickness and density along the landslide body at different stages of motion are given.

  6. Multidisciplinary Investigations of Submarine Flow to Biscayne Bay, Florida

    NASA Astrophysics Data System (ADS)

    Halley, R. B.; Reich, C. D.; Swarzenski, P. W.; Langevin, C. D.

    2005-05-01

    Biscayne Bay and Biscayne National Park (BNP) are located next to the Miami-Dade urban complex and are adjacent to the Dade County South Dade Landfill Facility and the Miami-Dade Water and Sewer South District Plant. The base of the landfill is lined to separate it from the underlying Miami Limestone, the host rock for the surficial Biscayne Aquifer. The sewage-treatment facility injects treated sewage into the lower Florida Aquifer (750 m) that is overlain by an aquitard termed the Middle Confining Unit (450 m). The Biscayne Aquifer (up to 50 m thick) borders the western margin of BNP, and the Floridan Aquifer underlies the entire park. There is concern about leakage of contaminated aquifer water into BNP and its potential effects on water quality. Groundwater flux to Biscayne Bay is being studied using pressure measurements and geochemical analyses from submarine wells, electromagnetic seepage meters, streaming resistivity profiling, and local and regional model simulations. Both seepage meters and water analyses provide point information that can be placed into the regional context provided by flow models and geochemical and geophysical profiling, which, in turn, constrain the groundwater contribution. Water samples were collected approximately quarterly from August 2002 until March 2004 from submarine wells along a transect through Biscayne Bay and across the reef to the shelf edge. Samples were analyzed for conductivity (salinity), dissolved oxygen, temperature, redox potential, nutrients, metals, strontium isotopes, radon, sulfate, and wastewater compounds. Low-salinity water was identified from nearshore wells and indicates seepage from the Biscayne Aquifer and/or surface-water intrusion into the rocks along western Biscayne Bay. Analyses of water samples (n = 109) collected from wells across the Florida shelf show no consistent evidence of wastewater contaminants occurring in groundwater beneath BNP. No significant leakage from the Floridan Aquifer

  7. 30 CFR 75.311 - Main mine fan operation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... back-up fan system— (1) Only persons necessary to evaluate the effect of the fan stoppage or restart... back-up fan system is used that does not provide the ventilating quantity provided by the main mine fan... movement. (h) Any atmospheric monitoring system operated during fan stoppages shall be intrinsically safe. ...

  8. The entrainment, pressure and flow process of a jet fan modeled in a square section wind tunnel

    SciTech Connect

    Mutama, K.R.; Hall, A.E.

    1995-12-31

    Jet fan (ductless fan) ventilation in underground mines and tunnels is a subject requiring further attention. At present there are no accepted procedures or guidelines for this type of ventilation. The main reason has been the absence of sufficient general data, which has hampered the development of rules. There is great potential for using jet fans in terms of both effectiveness and economics because they eliminate the need for ventilation tubing. In the present studies a procedure is described and results are presented from a jet fan modeled in a square section wind tunnel. The major purpose of the studies was to provide fundamental data on jet fan performance after it was realized that previous work had been limited and too site specific. The jet fan position in relation to the tunnel walls was varied in order to study the influence of confining walls on entrainment rates and the resulting aerodynamics. A clearer understanding of the fundamental principles of jet fan applications was obtained.

  9. Decline of the performance of a portable axial-flow fan due to the friction and duct bending loss of a connected flexible duct.

    PubMed

    Ojima, Jun

    2017-03-28

    In a job site, a portable fan is often used to ventilate a confined space. When a portable fan is applied to such a space, the actual ventilation flow rate must be accurately estimated in advance because the safety level of contaminant and oxygen concentrations in the space will determine the ventilation requirements. When a portable fan is used with a flexible duct, the actual flow rate of the fan decreases due to the friction and duct bending loss of the duct. Intending to show the decline of a fan performance, the author conducted laboratory experiments and reported the quantitative effect of the friction and duct bending loss of a flexible duct to the flow rate of a portable fan. Four commercial portable fans of different specifications were procured for the experiments, and the decline of the performance of each portable fan due to the friction loss etc. of a connected flexible duct was investigated by measuring actual flow rate. The flow rate showed an obvious decrease from the rated flow rate when a flexible duct was connected. Connection of a straight polyester flexible duct and a straight aluminum flexible duct reduced the flow rates to 81.2 - 52.9% and less than 50%, respectively. The flow rate decreased with an increase of the bend angle of the flexible duct. It is recommended that flow rate check of a portable fan should be diligently carried out in every job site.

  10. Sediment mass-flow processes on a depositional lobe, outer Mississippi Fan

    SciTech Connect

    Schwab, W.C.; Twichell, D.C.; Lee, H.J.; Nelson, C.H.; McArthur, W.G.; Locat, J.; Kenyon, N.H.

    1996-09-01

    As exploration for hydrocarbons moves toward subtler traps, channel-end sand deposits of deep-sea fans and related turbidite systems are among the key targets. SeaMARC 1A sidescan-sonar imagery and cores from the distal reaches of a depositional lobe on the Mississippi Fan show that channelized mass flow as the dominant mechanism for transport of silt and sand during the formation of this part of the fan. Sediments in these flows were rapidly deposited once outside of their confining channels. The depositional lobe is formed of a series of long, narrow sublobes composed of thin-bedded turbidites (normally graded siliciclastic sand and silt, 20 cm thick on average), debris-flow deposits (soft clay clasts up to 5 cm in diameter in a siliciclastic silt matrix, 48 cm thick on average), and background-sedimentation hemipelagic muds. The mass flows most likely originated from slope failure at the head of the Mississippi Canyon or on the outer continental shelf and flowed approximately 500 km to the distal reaches of the fan, with debris flow being the dominant flow type. An analysis that uses the geometry of the confining channels and strength properties of the debris-flow material shows that these thin debris flows could have traveled hundreds of kilometers on extremely small sea-floor slopes at low velocities if the flowing medium behaved as Bingham fluids and were steady-state phenomena.

  11. Enhanced Fan Noise Modeling for Turbofan Engines

    NASA Technical Reports Server (NTRS)

    Krejsa, Eugene A.; Stone, James R.

    2014-01-01

    This report describes work by consultants to Diversitech Inc. for the NASA Glenn Research Center (GRC) to revise the fan noise prediction procedure based on fan noise data obtained in the 9- by 15 Foot Low-Speed Wind Tunnel at GRC. The purpose of this task is to begin development of an enhanced, analytical, more physics-based, fan noise prediction method applicable to commercial turbofan propulsion systems. The method is to be suitable for programming into a computational model for eventual incorporation into NASA's current aircraft system noise prediction computer codes. The scope of this task is in alignment with the mission of the Propulsion 21 research effort conducted by the coalition of NASA, state government, industry, and academia to develop aeropropulsion technologies. A model for fan noise prediction was developed based on measured noise levels for the R4 rotor with several outlet guide vane variations and three fan exhaust areas. The model predicts the complete fan noise spectrum, including broadband noise, tones, and for supersonic tip speeds, combination tones. Both spectra and directivity are predicted. Good agreement with data was achieved for all fan geometries. Comparisons with data from a second fan, the ADP fan, also showed good agreement.

  12. Turbulent dispersion via fan-generated flows

    PubMed Central

    Halloran, Siobhan K.; Wexler, Anthony S.; Ristenpart, William D.

    2014-01-01

    Turbulent dispersion of passive scalar quantities has been extensively studied in wind tunnel settings, where the flow is carefully conditioned using flow straighteners and grids. Much less is known about turbulent dispersion in the “unconditioned” flows generated by fans that are ubiquitous in indoor environments, despite the importance of these flows to pathogen and contaminant transport. Here, we demonstrate that a point source of scalars released into an airflow generated by an axial fan yields a plume whose width is invariant with respect to the fan speed. The results point toward a useful simplification in modeling of disease and pollution spread via fan-generated flows. PMID:24932096

  13. The lift-fan aircraft: Lessons learned

    NASA Technical Reports Server (NTRS)

    Deckert, Wallace H.

    1995-01-01

    This report summarizes the highlights and results of a workshop held at NASA Ames Research Center in October 1992. The objective of the workshop was a thorough review of the lessons learned from past research on lift fans, and lift-fan aircraft, models, designs, and components. The scope included conceptual design studies, wind tunnel investigations, propulsion systems components, piloted simulation, flight of aircraft such as the SV-5A and SV-5B and a recent lift-fan aircraft development project. The report includes a brief summary of five technical presentations that addressed the subject The Lift-Fan Aircraft: Lessons Learned.

  14. Paraboloidal Antenna Radiates Fan Or Pencil Beams

    NASA Technical Reports Server (NTRS)

    Huang, John

    1989-01-01

    Shape of beam determined by type of feed. Theory and experiments show same paraboloidal antenna reflector used to radiate pencil beam or fan beam, depending on configuration of feed. Although pencil-shaped beam desirable in many applications, fan-shaped beam preferred in some scanning-radar and mapping-radar systems. Experiment performed with paraboloidal reflector having focal length of 48 in. (1.22 m) and diameter of 3.65 m. Shows fan beams generated in this way and not seriously distorted by feed offsets tested. Also shows because reflector in near field of feed, fan beam not necessarily focused by placing feed at focal plane.

  15. Turbulent dispersion via fan-generated flows

    NASA Astrophysics Data System (ADS)

    Halloran, Siobhan K.; Wexler, Anthony S.; Ristenpart, William D.

    2014-05-01

    Turbulent dispersion of passive scalar quantities has been extensively studied in wind tunnel settings, where the flow is carefully conditioned using flow straighteners and grids. Much less is known about turbulent dispersion in the "unconditioned" flows generated by fans that are ubiquitous in indoor environments, despite the importance of these flows to pathogen and contaminant transport. Here, we demonstrate that a point source of scalars released into an airflow generated by an axial fan yields a plume whose width is invariant with respect to the fan speed. The results point toward a useful simplification in modeling of disease and pollution spread via fan-generated flows.

  16. Reducing Unsteady Loads on a Piggyback Miniature Submarine

    NASA Technical Reports Server (NTRS)

    Lin, John

    2009-01-01

    A small, simple fixture has been found to be highly effective in reducing destructive unsteady hydrodynamic loads on a miniature submarine that is attached in piggyback fashion to the top of a larger, nuclear-powered, host submarine. The fixture, denoted compact ramp, can be installed with minimal structural modification, and the use of it does not entail any change in submarine operations.

  17. 36. VIEW OF CUPOLA, SUBMARINE ESCAPE TRAINING TANK, SHOWING ROVING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. VIEW OF CUPOLA, SUBMARINE ESCAPE TRAINING TANK, SHOWING ROVING RESCUE BELL SUSPENDED ABOVE TANK, WITH TWO-LOCK RECOMPRESSION CHAMBER AT REAR, LOOKING WEST. Photo taken after installation of recompression chamber in 1956. - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  18. 35. INTERIOR VIEW OF EQUIPMENT HOUSE, SUBMARINE ESCAPE TRAINING TANK, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. INTERIOR VIEW OF EQUIPMENT HOUSE, SUBMARINE ESCAPE TRAINING TANK, PRIOR TO ENLARGEMENT OF ROOM AND INSTALLATION OF TRIPLE-LOCK RECOMPRESSION CHAMBER IN 1957 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  19. 31. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION OF THE ELEVATOR AND PASSAGEWAYS TO THE 18- AND 50-FOOT LOCKS AND CUPOLA 1932 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  20. Sustaining U.S. Nuclear Submarine Design Capabilities

    DTIC Science & Technology

    2007-01-01

    Attack Narwhal 1 1969 Attack Lipscomb 1 1974 Attack The Submarine Design Process 9 Submarine Class Class Size Commission Dates Type of Submarine...class, EB had several designs in process, including the Narwhal , Lipscomb, and NR-1, which helped them bridge the gap. The Seawolf class (SSN 21) was

  1. Prototype Morphing Fan Nozzle Demonstrated

    NASA Technical Reports Server (NTRS)

    Lee, Ho-Jun; Song, Gang-Bing

    2004-01-01

    Ongoing research in NASA Glenn Research Center's Structural Mechanics and Dynamics Branch to develop smart materials technologies for aeropropulsion structural components has resulted in the design of the prototype morphing fan nozzle shown in the photograph. This prototype exploits the potential of smart materials to significantly improve the performance of existing aircraft engines by introducing new inherent capabilities for shape control, vibration damping, noise reduction, health monitoring, and flow manipulation. The novel design employs two different smart materials, a shape-memory alloy and magnetorheological fluids, to reduce the nozzle area by up to 30 percent. The prototype of the variable-area fan nozzle implements an overlapping spring leaf assembly to simplify the initial design and to provide ease of structural control. A single bundle of shape memory alloy wire actuators is used to reduce the nozzle geometry. The nozzle is subsequently held in the reduced-area configuration by using magnetorheological fluid brakes. This prototype uses the inherent advantages of shape memory alloys in providing large induced strains and of magnetorheological fluids in generating large resistive forces. In addition, the spring leaf design also functions as a return spring, once the magnetorheological fluid brakes are released, to help force the shape memory alloy wires to return to their original position. A computerized real-time control system uses the derivative-gain and proportional-gain algorithms to operate the system. This design represents a novel approach to the active control of high-bypass-ratio turbofan engines. Researchers have estimated that such engines will reduce thrust specific fuel consumption by 9 percent over that of fixed-geometry fan nozzles. This research was conducted under a cooperative agreement (NCC3-839) at the University of Akron.

  2. An experimental approach to submarine canyon evolution

    NASA Astrophysics Data System (ADS)

    Lai, Steven Y. J.; Gerber, Thomas P.; Amblas, David

    2016-03-01

    We present results from a sandbox experiment designed to investigate how sediment gravity flows form and shape submarine canyons. In the experiment, unconfined saline gravity flows were released onto an inclined sand bed bounded on the downstream end by a movable floor that was used to increase relief during the experiment. In areas unaffected by the flows, we observed featureless, angle-of-repose submarine slopes formed by retrogressive breaching processes. In contrast, areas influenced by gravity flows cascading across the shelf break were deeply incised by submarine canyons with well-developed channel networks. Normalized canyon long profiles extracted from successive high-resolution digital elevation models collapse to a single profile when referenced to the migrating shelf-slope break, indicating self-similar growth in the relief defined by the canyon and intercanyon profiles. Although our experimental approach is simple, the resulting canyon morphology and behavior appear similar in several important respects to that observed in the field.

  3. Pore-fluid chemistry along the main axis of an active lobe at the Congo deep-sea fan

    NASA Astrophysics Data System (ADS)

    Croguennec, C.; Ruffine, L.; Guyader, V.; Le Bruchec, J.; Ruesch, B.; Caprais, J.; Cathalot, C.; de Prunelé, A.; Germain, Y.; Bollinger, C.; Dennielou, B.; Olu, K.; Rabouille, C.

    2013-12-01

    The distal lobes of the Congo deep-sea fan constitute a unique in situ laboratory to study early diagenesis of marine sediments. They are located at water depth of about 5000 m and result from the deposition of sediment transported by turbidity currents along the channel-levee systems and submarine canyon connected to the Congo River. Thus, a huge amount of organic matter, transported from the river to the lobes, undergoes decomposition processes involving different oxidants present within the sedimentary column. This drastically changes the chemistry of the pore fluids, allowing the occurence of a succession of biogeochemical processes. The present study is part of an ongoing project which aims at better understanding the role and the fate of organic matter transported to the lobe systems, as well as its implication in the distribution of the living communities encountered there. Thus, pore fluids have been sampled from 8 Calypso cores in order to determine the concentration of dissolved elements. Five sites have been investigated: four of them are located along the main axis of a currently active lobe, the last one being located on a lobe disconnected from the chenals. The analyses of methane, major (Cl, SO4, Mg, Ca, K, Na) and minor (Sr, Ba, B, Li, Mn) elements have been carried out along with total alkalinity determination. The resulting profiles show a highly heterogeneous pore-fluid chemistry. Sulphate concentration near the seawater/sediment interface varies from 3 to 29 mM, indicating intense sulphate reduction. Surprisingly the lowest values are found at the site which is disconnected from the active lobe. The manganese cycle is well defined for all cores. The core recovered at the more distal lobe exhibits very peculiar pore-fluid profiles which are likely related to a geological event, most likely sediment slide and remobilization. References: Babonneau, N., Savoye, B., Cremer, M. & Klein, B., 2002. Morphology and architecture of the present canyon and

  4. Placer lag deposits in submarine channels in the Gulf of Alaska

    SciTech Connect

    Dobson, M.R. ); Huggett, Q. )

    1990-06-01

    GLORIA surveys in the Gulf of Alaska during 1989 have revealed details of sediment transport systems that cross the Slope, Rise, and adjacent abyssal plain. Two systems dominate: channel-levee complexes that promote the construction of major fans, and large single channels with subdued overbank activities which terminate as extended sediment lobes that may coalesce to give sand plains. Both channel types originate from Upper Slope gulley zones developed on rapidly dumped shelf edge fans associated with major tidewater glaciers that during periods of climatic deterioration and lower sea levels extended across the narrow shelf to the top of the Slope. Thus, the sediment source for these channel systems consists of unsorted rapidly abandoned glacial debris. The nature of initial emplacement of unsorted sediments is significant because the Alaskan provenance area is rich in heavy or placer type minerals; particularly those with economic value such as gold and platinum. The reworking of these sediments along submarine channels that morphologically have strong similarities with subaerial systems makes placer prospecting a viable proposition. Surveys using GLORIA, 10 KHz, and 3.5 KHz profilers together with a 140 in.{sup 3} airgun array have allowed the identification of prospecting sites and provided the control for the development of predictive models for those processes that ensure heavy mineral concentration in the transport regimes identified for this margin. Importantly, because this margin is an active transform type, individual fans, sourcing as they do from restricted sites along this coastline, are short-lived such that even abandoned fans offer prospects for the surveyor.

  5. Containment of composite fan blades

    NASA Technical Reports Server (NTRS)

    Stotler, C. L.; Coppa, A. P.

    1979-01-01

    A lightweight containment was developed for turbofan engine fan blades. Subscale ballistic-type tests were first run on a number of concepts. The most promising configuration was selected and further evaluated by larger scale tests in a rotating test rig. Weight savings made possible by the use of this new containment system were determined and extrapolated to a CF6-size engine. An analytical technique was also developed to predict the released blades motion when involved in the blade/casing interaction process. Initial checkout of this procedure was accomplished using several of the tests run during the program.

  6. Geomorphic process fingerprints in submarine canyons

    USGS Publications Warehouse

    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.

  7. Understanding steady-state Deep Submarine Groundwater Discharge: a case study in Northern Israel

    NASA Astrophysics Data System (ADS)

    Paldor, Anner; Aharonov, Einat; Katz, Oded

    2017-04-01

    Deep Submarine Groundwater Discharge (DSGD) is a ubiquitous and highly significant phenomenon, yet it remains poorly understood. Here we use numerical modeling (FEFLOW) to investigate a case study of DSGD offshore northern Israel, aiming to unravel the main features and mechanics of steady-state DSGD: the hydrology that enables its formation, the controls on rates and salinity of seepage, and the residence time of fluid underground. In addition, we investigate the geometry of the fresh-salt water interface within the seeping offshore aquifer. The first part of this work constructs a large scale (70 km) geologic cross-section of our case-study region. The mapping suggests outcropping of confined aquifer strata (Upper Cenomanian Judea Group) on the continental shelf break, 5-15 km offshore. The second part consists of hydrological simulations of DSGD from a confined aquifer similar to the case-study aquifer. The main findings are thus: steady-state DSGD from a confined aquifer occurs far offshore even under moderate heads. It is accompanied by a circulation cell that forms around an intrinsic freshwater-seawater interface. Circulation consists of seawater entering the confined aquifer at the exposed section offshore, mixing with terrestrial groundwater within the aquifer, and seeping saline water out the upper part of the exposed section. In addition, the simulated confined aquifer displays a very flat fresh-salt water interface extending far offshore, as observed in natural offshore aquifers. Preliminary results of a hydrographic survey in the area of study suggest a low-salinity anomaly close to the seafloor, implying seepage of brines in that area, as expected from the model. These new insights have potentially important implications for coastal hydrology, seawater chemistry, biogeochemistry, and submarine slope instability.

  8. Suppression of broadband noise radiated by a low-speed fan in a duct.

    PubMed

    Huang, L; Ma, X; Feng, L G

    2010-07-01

    Attenuation of ducted fan noise remains a technical challenge in the low frequency range as traditional duct lining becomes ineffective. This study proposes a reactive method to suppress the sound radiation from an axial-flow fan. The method is particularly effective in the low frequency region and covers a broad band. Its effect is derived from two mechanisms. One is the reduction in the confining effects of duct walls when the duct radius is increased; the other is the acoustic interference between the direct radiation from the fan and reflections by the duct junctions. This interference is always destructive for axial dipoles when the frequency approaches zero. This performance differs from normal passive control methods, which become totally ineffective toward zero frequency. An approximate plane-wave theory explains the essential physics of the method, and its quantitative prediction is found to agree well with a full numerical simulation using a spectral method of Chebyshev collocation. The latter is validated by experiment using an axial-flow fan in a duct of finite length. Broadband noise reduction is achieved while the flow speed is kept unchanged. Practical difficulties of implementation for a fan with high pressure increase are discussed.

  9. Autogenic dynamics of debris-flow fans

    NASA Astrophysics Data System (ADS)

    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

  10. Decision Support for Attack Submarine Commanders.

    DTIC Science & Technology

    1980-10-01

    AD-AO95 892 DECISION SCIENCE CONSORTIUM INC FALLS CHURCH VA F./e 12/2 DECISION SUPPORT FOR ATTACK SUBMARINE COMMANDERS. (U) OCT 80 M S COHEN, R V...BROWN N00014-80-C-0046 UNCLASSIFIED TR-8S-11 ML DECISIN IEN$CE CUIVSURTiUM, MrC. DECISION SUPPORT FOR A TTA CK SUBMARINE COMMANDERS Marvin S . Cohen and...on reverse) DDI ,o..ŕ 1473 EDITION OF I NOV 65 IS OISOLCTZ Unclassified S /N 0102-014-6601 1 SECURITY CLASIFICATION OF TNIS PAGE (10bon DW& tateo* 01

  11. A model for the submarine depthkeeping team

    NASA Technical Reports Server (NTRS)

    Ware, J. R.; Best, J. F.; Bozzi, P. J.; Kleinman, D. W.

    1981-01-01

    The most difficult task the depthkeeping team must face occurs during periscope-depth operations during which they may be required to maintain a submarine several hundred feet long within a foot of ordered depth and within one-half degree of ordered pitch. The difficulty is compounded by the facts that wave generated forces are extremely high, depth and pitch signals are very noisy and submarine speed is such that overall dynamics are slow. A mathematical simulation of the depthkeeping team based on the optimal control models is described. A solution of the optimal team control problem with an output control restriction (limited display to each controller) is presented.

  12. Biomonitoring of physiological status and cognitive performance of underway submariners undergoing a novel watch-standing schedule

    NASA Astrophysics Data System (ADS)

    Duplessis, C. A.; Cullum, M. E.; Crepeau, L. J.

    2005-05-01

    Submarine watch-standers adhere to a 6 hour-on, 12 hour-off (6/12) watch-standing schedule, yoking them to an 18-hr day, engendering circadian desynchronization and chronic sleep deprivation. Moreover, the chronic social crowding, shift work, and confinement of submarine life provide additional stressors known to correlate with elevated secretory immunoglobulin A (sIgA) and cortisol levels, reduced performance, immunologic dysfunction, malignancies, infections, gastrointestinal illness, coronary disease, anxiety, and depression. We evaluated an alternative, compressed, fixed work schedule designed to enhance circadian rhythm entrainment, sleep hygiene, performance, and health on 10 underway submariners, who followed the alternative and 6/12 schedules for approximately 2 weeks each. We measured subjects" sleep, cognitive performance, and salivary biomarker levels. Pilot analysis of the salivary data on one subject utilizing ELISA suggests elevated biomarker levels of stress. Average PM cortisol levels were 0.2 μg/L (normal range: nondetectable - 0.15 μg/L), and mean sIgA levels were 562 μg/ml (normal range: 100-500 μg/ml). Future research exploiting real-time salivary bioassays, via fluorescent polarimetry technology, identified by the Office of Naval Research (ONR) as a future Naval requirement, allows researchers to address correlations between stress-induced elaboration of salivary biomarkers with physiological and performance decrements, thereby fostering insight into the underway submariner"s psychoimmunological status. This may help identify strategies that enhance resilience to stressors. Specifically, empirically-based modeling can identify optimal watch-standing schedules and stress-mitigating procedures -- within the operational constraints of the submarine milieu and the mission --that foster improved circadian entrainment and reduced stress reactivity, enhancing physiological health, operational performance, safety, and job satisfaction.

  13. Effects of Alluvial and Debris Flow Fans on Channel Morphology in Idaho, Washington, and Oregon

    NASA Astrophysics Data System (ADS)

    Bigelow, P. E.; Benda, L.; Miller, D.; Andras, K.

    2003-12-01

    major gradient nick points on mainstem channels (e.g. bedrock, rock falls, canyon constrictions, channel bends, etc.). However, not all channels are prone to tributary fan effects. Steep and confined mountain channels with high stream power may quickly transport deposits from debris flow and alluvial fans, leaving no morphological effects. Overall, these field studies provide a possible physical basis for recent observations of increased habitat use near tributary junctions (e.g. salmon spawning density, aquatic invertebrate density) and underpin emerging stream network theory on the organization of disturbance in creating and maintaining a variety of habitat in aquatic and riparian ecosystems.

  14. PEFCs for naval ships and submarines: many tasks, one solution

    NASA Astrophysics Data System (ADS)

    Sattler, Gunter

    Polymer electrolyte fuel cells (PEFCs) for air-independent propulsion systems have been developed and tested under submarine conditions and are thus ready for submarine application. A demand analysis and the presentation of the requirements for naval surface ships and submarines will be followed by the description of the realisation concepts for PEFC propulsion plants. Based on the results of FC operation on board of a submarine and the system design for the new German submarine Class 212, synergy effects will be derived from that for surface ships. Finally, future aspects will be pointed out including PEFC propulsion for merchant ships.

  15. The Submarine Flanks of Anatahan Volcano

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    The submarine flanks of Anatahan volcano were surveyed with EM300 multibeam sonar and the MR1 sidescan sonar from the R/V Thomas G. Thompson in February 2003. This was part of a larger survey of over 50 submarine volcanoes within the Marianas volcanic arc between 13° 10'N and 23° 10'N (see Embley et al. and Baker et al. abstracts, this meeting). This work was part of a multi-year study of seafloor volcanism in diverse tectonic settings, funded by NOAA's Office of Ocean Exploration. (see: http://oceanexplorer.noaa.gov/explorations/03fire/). The island of Anatahan has a maximum elevation of 798 m, but its submarine flanks descend to depths of 2000-2600 m, so most of the volcano lies below sea level. The submarine part of the volcano is elongated in the east-west direction, like the island. Conspicuous in the bathymetry are numerous small parasitic cones and hummocky ridges on the southwest and east submarine flanks of the island that radiate outward (downslope) from the island. These features appear as areas of high reflectivity in the MR1 sidescan sonar and some have distinctly lobate outlines, suggesting that they are areas of relatively young lava flows. Some of these lava flows extend up to 15 km from the coastline of the island and to depths below 2000 m. The upslope sources of these lavas are often ambiguous, but we interpret that they were erupted underwater (as opposed to erupted on land and then flowing into the ocean) because they are associated with cones and ridges that may be vent areas. The other flanks of the island appear to be draped in volcaniclastic material that has been transported downslope from the shoreline, in some cases as distinct flows that radiate outward in braided channels that have slightly higher reflectivity than surrounding areas in the sidescan imagery. These fragmental flows also extend to depths below 2000 m, especially on the west and south flanks of the island. The most prominent feature in the bathymetry around Anatahan is a

  16. Drive Fan for the Icing Research Tunnel

    NASA Image and Video Library

    1944-11-21

    View of the drive fan for the Icing Research Tunnel at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory in Cleveland, Ohio. The tunnel was built in the early 1940s to study the formation of ice on aircraft surfaces and methods of preventing or eradicating that ice. Ice buildup adds extra weight, effects aerodynamics, and sometimes blocks airflow through engines. The original 4100-horsepower induction motor was coupled directly to the 24-foot-diameter fan. The 12 wooden fan blades were protected on their leading edge by a neoprene boot. The system could create air speeds up to 300 miles per hour through the tunnel’s 6- by 9-foot test section. The large tail faring extending from the center of the fan is used to guide the airflow down the tunnel in a uniform way. A new 5000-horsepower motor was installed in 1987, and the original fan blades were replaced in 1993.

  17. Advanced Noise Control Fan Aerodynamic Performance

    NASA Technical Reports Server (NTRS)

    Bozak, Richard F., Jr.

    2009-01-01

    The Advanced Noise Control Fan at the NASA Glenn Research Center is used to experimentally analyze fan generated acoustics. In order to determine how a proposed noise reduction concept affects fan performance, flow measurements can be used to compute mass flow. Since tedious flow mapping is required to obtain an accurate mass flow, an equation was developed to correlate the mass flow to inlet lip wall static pressure measurements. Once this correlation is obtained, the mass flow for future configurations can be obtained from the nonintrusive wall static pressures. Once the mass flow is known, the thrust and fan performance can be evaluated. This correlation enables fan acoustics and performance to be obtained simultaneously without disturbing the flow.

  18. Fan-fold shielded electrical leads

    DOEpatents

    Rohatgi, R.R.; Cowan, T.E.

    1996-06-11

    Disclosed are fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate. 3 figs.

  19. Blade Vibration Measurement System for Unducted Fans

    NASA Technical Reports Server (NTRS)

    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.

  20. Supersonic through-flow fan assessment

    NASA Technical Reports Server (NTRS)

    Kepler, C. E.; Champagne, G. A.

    1988-01-01

    A study was conducted to assess the performance potential of a supersonic through-flow fan engine for supersonic cruise aircraft. It included a mean-line analysis of fans designed to operate with in-flow velocities ranging from subsonic to high supersonic speeds. The fan performance generated was used to estimate the performance of supersonic fan engines designed for four applications: a Mach 2.3 supersonic transport, a Mach 2.5 fighter, a Mach 3.5 cruise missile, and a Mach 5.0 cruise vehicle. For each application an engine was conceptualized, fan performance and engine performance calculated, weight estimates made, engine installed in a hypothetical vehicle, and mission analysis was conducted.

  1. Fan-fold shielded electrical leads

    DOEpatents

    Rohatgi, Rajeev R.; Cowan, Thomas E.

    1996-01-01

    Fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate.

  2. Climatic and Tectonic Controls on Alluvial Fan Evolution: The Lost River Range, Idaho

    NASA Astrophysics Data System (ADS)

    Phillips, R. J.; Pierce, J. L.; Sharp, W. D.; Pierce, K. L.

    2006-12-01

    In the northern Basin &Range, alluvial fans developed along the Lost River range-front consist of several distinct inset fan segments with concave-up radial profiles. Multiple large radius (>5 km), shallow (2- 3°), alluvial fans extend across and beyond the active, ~140-km-long, normal Lost River fault. These large fans are relict features, formed by major sheetfloods that occurred intermittently between ~15-180 ka. More recent deposition has been dominated by debris-flows that form small-radius (<2 km), steep (8- 17°), fans closely confined to the mountain front [1,2]. In order to determine the timing of fan surface stabilization, we have undertaken precise mass spectrometric 230Th/U dating of pedogenic carbonate from calcic soils that mantle fan surfaces on the Arco fault segment. Careful selection of mg-size samples of dense soil carbonate pebble coats, from within a trench that cuts through gravelly fan deposits, indicates that the fan soils are geochemically suitable for uranium-series dating (median U=7ppm, 232Th=0.09ppm, 232Th/230Th=154). 230Th/U analysis of these calcic soils can thus provide precise temporal constraints on intervals of surface stability and subsequent soil formation. The oldest fan surface (Qfo1, 178+/-8 ka), exposed within the footwall of the trench, suggests an interval of surface stability, indicating that the fan was likely abandoned due to incision early in MIS 6. Incision may have resulted from surface faulting along the Arco segment of the Lost River fault, but could relate to changes in stream power or sediment supply associated with climatic change or with auto-cyclic variations within the drainage basin. A younger incised and faulted fan surface (Qfo2, 69+/-6 ka), likely represents active alluviation at the beginning of MIS 4 and, since it formed as hanging-wall alluvial gravel, provides age limits on an episode of fault displacement between Qfo1 and Qfo2. In situ pedogenic carbonate coats on sub-angular gravels within the

  3. Physical and chemical properties of submarine basaltic rocks from the submarine flanks of the Hawaiian Islands

    USGS Publications Warehouse

    Yokose, H.; Lipman, P.W.; Kanamatsu, T.

    2005-01-01

    To evaluate physical and chemical diversity in submarine basaltic rocks, approximately 280 deep submarine samples recovered by submersibles from the underwater flanks of the Hawaiian Islands were analyzed and compared. Based on observations from the submersibles and hand specimens, these samples were classified into three main occurrence types (lavas, coarse-grained volcaniclastic rocks, and fine-grained sediments), each with several subtypes. The whole-rock sulfur content and porosity in submarine basaltic rocks, recovered from depths greater than 2000 m, range from < 10 ppm and 2 vol.% to 2200 ppm and 47 vol.%, respectively. These wide variations cannot be due just to different ambient pressures at the collection depths, as inferred previously for submarine erupted lavas. The physical and chemical properties of the recovered samples, especially a combination of three whole-rock parameters (Fe-oxidation state, Sulfur content, and Porosity), are closely related to the occurrence type. The FSP triangular diagram is a valuable indicator of the source location of basaltic fragments deposited in deep submarine areas. This diagram can be applied to basaltic rocks such as clasts in debris-flow deposits, submarine-emplaced lava flows that may have crossed the shoreline, and slightly altered geological samples. ?? 2005 Elsevier B.V. All rights reserved.

  4. Seatbelt submarining injury and its prevention countermeasures: How a cantilever seat pan structure exacerbate submarining

    PubMed Central

    Thorbole, Chandrashekhar K.

    2015-01-01

    The purpose of this study and a case report was to demonstrate seat belt webbing induced injury due to seatbelt submarining during the frontal motor vehicle crash. Submarining is an undesired phenomenon during a frontal crash scenario and is dependent on design features of the seat pan and seatbelt system. The lack of adequate anti-submarining features at any seating position with three-point restraint can cause abdominal solid and hollow organ injuries. This paper reports a case of submarining and factors that exacerbated this phenomenon leading to critical occupant abdominal injury. This case report and the following injury causation analysis demonstrate the shortcomings of a cantilever seat pan design in context to the occupant safety. The inadequate seat pan anti-submarining feature in association with lack of seatbelt load-limiter and Pretensioner reduces the level of occupant protection offered by the seat belt system in the rear seat. This case report shows the dangers of cantilever seat pan design and its association with increased risk of submarining causing severe abdominal injuries. PMID:26985421

  5. Ice-Confined Basaltic Lava Flows: Review and Discussion

    NASA Astrophysics Data System (ADS)

    Skilling, I.; Edwards, B. R.

    2012-12-01

    Basaltic lavas that are interpreted as having been emplaced in subglacial or ice-confined subaerial settings are known from several localities in Iceland, British Columbia and Antarctica. At least four different types of observations have been used to date to identify emplacement of basaltic lavas in an ice-rich environment: i) gross flow morphology, ii) surface structures, iii) evidence for ice-confined water during emplacement, and iv) lava fracture patterns. Five types of ice-confined lava are identified: sheets, lobes, mounds, linear ridges and sinuous ridges. While the appearance of lavas is controlled by the same factors as in the submarine environment, such as the geometry and configuration of vents and lava tubes, flow rheology and rates, and underlying topography, the presence of ice can lead to distinct features that are specific to the ice-confined setting. Other types have very similar or identical equivalents in submarine environment, albeit with some oversteepening/ice contact surfaces. Ice-confined lavas can form as (1) subaerial or subaqueous lavas emplaced against ice open to the air, (2) subaqueous lavas emplaced into pre-existing sub-ice drainage networks, and (3) subaqueous lavas emplaced into ponded water beneath ice. Their surface structures reflect the relationship between rates of lava flow emplacement at the site of ice-water-lava contact, ice melting and water drainage. Variations in local lava flow rates could be due to lava cooling, constriction, inflation, tube development, ice melting, ice collapse, lava collapse, changes in eruption rate etc. Episodes of higher lava flow rate would favour direct ice contact and plastic compression against the ice, generating oversteepened and/or overthickened chilled margins, cavities in the lava formed by melting of enveloped ice blocks (cryolith cavities) and structures such as flattened pillows and lava clasts embedded into the glassy margins. Melting back of the confining ice generates space to

  6. Using multiple geochemical tracers to characterize the hydrogeology of the submarine spring off Crescent Beach, Florida

    USGS Publications Warehouse

    Swarzenski, P.W.; Reich, C.D.; Spechler, R.M.; Kindinger, J.L.; Moore, W.S.

    2001-01-01

    A spectacular submarine spring is located about 4 km east of Crescent Beach, FL, in the Atlantic Ocean. The single vent feature of Crescent Beach Spring provides a unique opportunity to examine onshore-offshore hydrogeologic processes, as well as point source submarine ground water discharge. The Floridan aquifer system in northeastern Florida consists of Tertiary interspersed limestone and dolomite strata. Impermeable beds confine the water-bearing zones under artesian pressure. Miocene and younger confining strata have been eroded away at the vent feature, enabling direct hydrologic communication of Eocene ground water with coastal bottom waters. The spring water had a salinity of 6.02, which was immediately diluted by ambient seawater during advection/mixing. The concentration of major solutes in spring water and onshore well waters confirm a generalized easterly flow direction of artesian ground water. Nutrient concentrations were generally low in the reducing vent samples, and the majority of the total nitrogen species existed as NH3. The submarine ground water tracers, Rn-222 (1174 dpm I-1, dpm), methane (232 nM) and barium (294.5 nM) were all highly enriched in the spring water relative to ambient seawater. The concentrations of the reverse redox elements U, V and Mo were expectedly low in the submarine waters. The strontium isotope ratio of the vent water (87Sr/86Sr = 0.70798) suggests that the spring water contain an integrated signature indicative of Floridan aquifer system ground water. Additional Sr isotopic ratios from a series of surficial and Lower Floridan well samples suggest dynamic ground water mixing, and do not provide clear evidence for a single hydrogeologic water source at the spring vent. In this karst-dominated aquifer, such energetic mixing at the vent feature is expected, and would be facilitated by conduit and fractured flow. Radium isotope activities were utilized to estimate flow-path trajectories and to provide information on

  7. Experimental Study of Alluvial Fan Formation

    NASA Astrophysics Data System (ADS)

    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).

  8. Biochemical and Hematologic Profiles of 1000 Submariners

    DTIC Science & Technology

    1977-03-01

    neutrophil and leucocyte levels, serum cholesterol , and both fasting and postprandial glucose correlated positively with age; serum al- kaline phosphatase... postprandial glucose, and cholesterol may be seen to correlate positively and significantly with age after correlation effects attributed to length... cholesterol content and alkaline phosphatase activity; after a loading test, glucose levels showed a negative relationship to length of submarine service

  9. "Internal Waves" Advancing along Submarine Canyons.

    PubMed

    Shepard, F P; Marshall, N F; McLoughlin, P A

    1974-01-18

    Patterns of alternating up- and downcanyon currents have been traced along the axes of submarine canyons off California. The patterns arrive later at stations nearer the heads of coastal canyons. Where a canyon heads between two islands, the patterns advance down the axis. The propagation speeds of these patterns were estimated as 25 to 88 centimeters per second. Internal waves are the probable explanation.

  10. Addressing submarine geohazards through scientific drilling

    NASA Astrophysics Data System (ADS)

    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

  11. Chemical environments of submarine hydrothermal systems

    NASA Technical Reports Server (NTRS)

    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

  12. Phase 1 Final Report: Titan Submarine

    NASA Technical Reports Server (NTRS)

    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

  13. The World's Largest Submarine Canyon—Kroenke Canyon in the Western Equatorial Pacific

    NASA Astrophysics Data System (ADS)

    Coffin, M. F.; Adams, N.; Whittaker, J. M.; Lucieer, V.; Heckman, M.; Ketter, T.; Neale, J. F.; Reyes, A.; Travers, A.

    2015-12-01

    Kroenke Canyon lies on the Ontong Java Plateau (OJP) in the western Equatorial Pacific, between the Solomon Islands and the Federated States of Micronesia. In late 2014 aboard the Schmidt Ocean Institute's RV Falkor, we mapped, albeit incompletely, the Canyon for the first time, revealing that it is both the longest (>700 km) and the most voluminous (>6800 km3) submarine canyon yet discovered on Earth. Kroenke Canyon appears to originate in the vicinity of Ontong Java (Solomon Islands) and Nukumanu (Papua New Guinea) atolls, and presumably began to develop when the atolls were high-standing volcanic islands surmounting the ~120 Ma igneous basement of the OJP. The Canyon is characterised by numerous tributaries and significant mass wasting. Kroenke Canyon incises the layer-cake stratigraphy of OJP sediment and sedimentary rock, mostly carbonate with some interbedded chert, which has provided numerous slip surfaces for submarine landslides. The carbonate compensation depth (CCD) roughly coincides with the depth of the transition between the OJP and the neighbouring Nauru Basin. As a result, despite the large volume of sediment eroded and transported by canyon-forming processes, only a minor fan is evident in the Nauru Basin because most of the carbonate has dissolved.

  14. Submarine glacial landforms record Late Pleistocene ice-sheet dynamics, Inner Hebrides, Scotland

    NASA Astrophysics Data System (ADS)

    Dove, Dayton; Arosio, Riccardo; Finlayson, Andrew; Bradwell, Tom; Howe, John A.

    2015-09-01

    We use ∼7000 km2 of high-resolution swath bathymetry data to describe and map the submarine glacial geomorphology, and reconstruct Late Pleistocene ice sheet flow configurations and retreat dynamics within the Inner Hebrides, western Scotland. Frequently dominated by outcrops of structurally complex bedrock, the seabed also comprises numerous assemblages of well-preserved glacigenic landforms typical of grounded ice sheet flow and punctuated ice-margin retreat. The occurrence and character of the glacially streamlined landforms is controlled in part by the shallow geology and topography, however these factors alone cannot account for the location, orientation, and configuration of the observed landforms. We attribute the distribution of these elongate streamlined landforms to the onset zone of the former Hebrides Ice Stream (HIS) - part of a major ice stream system that drained 5-10% of the last British-Irish Ice Sheet (BIIS). We suggest this geomorphic signature represents the transition from slow 'sheet flow' to 'streaming flow' as ice accelerated out from an environment characterized by numerous bedrock obstacles (e.g. islands, headlands), towards the smooth, sediment dominated shelf. The majority of streamlined landforms associated with the HIS indicate ice sheet flow to the southwest, with regional-scale topography clearly playing a major role in governing the configuration of flow. During maximal glacial conditions (∼29-23 ka) we infer that the HIS merged with the North Channel-Malin Shelf Ice Stream to form a composite ice stream system that ultimately reached the continental shelf edge at the Barra-Donegal Trough-Mouth Fan. Taken collectively however, the pattern of landforms now preserved at seabed (e.g. convergent flow indicators, cross-cutting flow sets) is more indicative of a thinning ice mass, undergoing reorganization during overall ice sheet retreat (during latter stages of Late Weischselian glaciation). Suites of moraines overprinting the

  15. TBCC Fan Stage Operability and Performance

    NASA Technical Reports Server (NTRS)

    Suder, Kenneth L.

    2007-01-01

    NASA s Fundamental Aeronautics Program is investigating turbine-based propulsion systems for access to space because it provides the potential for aircraft-like, space-launch operations that may significantly reduce launch costs and improve safety. Studies performed under NASA s NGLT and the NASP High Speed Propulsion Assessment (HiSPA) program indicated a variable cycle turbofan/ramjet was the best configuration to satisfy access-to-space mission requirements because this configuration maximizes the engine thrust-to-weight ratio while minimizing frontal area. To this end, NASA and GE teamed to design a Mach 4 variable cycle turbofan/ramjet engine for access to space. To enable the wide operating range of a Mach 4+ variable cycle turbofan ramjet required the development of a unique fan stage design capable of multi-point operation to accommodate variations in bypass ratio (10X), fan speed (7X), inlet mass flow (3.5X), inlet pressure (8X), and inlet temperature (3X). The primary goal of the fan stage was to provide a high pressure ratio level with good efficiency at takeoff through the mid range of engine operation, while avoiding stall and losses at the higher flight Mach numbers, without the use of variable inlet guide vanes. Overall fan performance and operability therefore requires major consideration, as competing goals at different operating points and aeromechanical issues become major drivers in the design. To mitigate risk of meeting the unique design requirements for the fan stage, NASA and GE teamed to design and build a 57% engine scaled fan stage to be tested in NASA s transonic compressor facility. The objectives of this test are to assess the aerodynamic and aero mechanic performance and operability characteristics of the fan stage over the entire range of engine operation including: 1) sea level static take-off, 2) transition over large swings in fan bypass ratio, 3) transition from turbofan to ramjet, and 4) fan windmilling operation at high Mach

  16. Turbofan gas turbine engine with variable fan outlet guide vanes

    NASA Technical Reports Server (NTRS)

    Wood, Peter John (Inventor); Zenon, Ruby Lasandra (Inventor); LaChapelle, Donald George (Inventor); Mielke, Mark Joseph (Inventor); Grant, Carl (Inventor)

    2010-01-01

    A turbofan gas turbine engine includes a forward fan section with a row of fan rotor blades, a core engine, and a fan bypass duct downstream of the forward fan section and radially outwardly of the core engine. The forward fan section has only a single stage of variable fan guide vanes which are variable fan outlet guide vanes downstream of the forward fan rotor blades. An exemplary embodiment of the engine includes an afterburner downstream of the fan bypass duct between the core engine and an exhaust nozzle. The variable fan outlet guide vanes are operable to pivot from a nominal OGV position at take-off to an open OGV position at a high flight Mach Number which may be in a range of between about 2.5-4+. Struts extend radially across a radially inwardly curved portion of a flowpath of the engine between the forward fan section and the core engine.

  17. Radially leaned outlet guide vanes for fan source noise reduction

    NASA Technical Reports Server (NTRS)

    Kazin, S. B.

    1973-01-01

    Two quiet engine program half scale fans one with a subsonic and the other with a supersonic fan tip speed at takeoff were run with 30 degree leaned and radial outlet guide vanes. Acoustic data at takeoff fan speed on the subsonic tip speed fan showed decreases in 200-foot sideline noise of from 1 to 2 PNdb. The supersonic tip speed fan a takeoff fan speed, however, showed noise increases of up 3 PNdb and a decrease in fan efficiency. At approach fan speed, the subsonic tip speed fan showed a noise decrease of 2.3 PNdb at the 200-foot sideline maximum angle and an increase in efficiency. The supersonic tip speed fan showed noise increase of 3.5 PNdb and no change in efficiency. The decrease in fan efficiency and the nature of the noise increase largely high frequency broadband noise lead to the speculation that an aerodynamic problem occurred.

  18. Highly Loaded Fan by Using Tandem Cascade Rotor Blade

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroaki; Suga, Shinya; Matsuoka, Akinori

    For axial flow compressors and fans in the aircraft engines higher pressure ratio is required in order to attain the high thrust engines. In this study, the fan with the tandem cascades was introduced to increase the fan pressure ratio. The use of tandem cascades in the fan allows savings in length and weight and therefore a compact fan could be built. The design of fan with tandem cascades and the fan testing were carried out to develop the high pressure ratio fan for the Air Turbo Ramjet (ATR) propulsion system. The ATR is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds. In particular, high fan pressure ratio contributes to increase the engine thrust during subsonic flight at which the engine does not make use of ram effect. The results of the fan testing indicate that the pressure ratio of 2.2 is achieved in single stage fan.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Compressor and fan wake characteristics

    NASA Technical Reports Server (NTRS)

    Reynolds, B.; Hah, C.; Lakshminarayana, B.; Ravindranath, A.

    1978-01-01

    A triaxial probe and a rotating conventional probe, mounted on a traverse gear operated by two step motors were used to measure the mean velocities and turbulence quantities across a rotor wake at various radial locations and downstream stations. The data obtained was used in an analytical model developed to study how rotor flow and blade parameters and turbulence properties such as energy, velocity correlations, and length scale affect the rotor wake characteristics and its diffusion properties. The model, includes three dimensional attributes, can be used in predicting the discrete as well as broadband noise generated in a fan rotor, as well as in evaluating the aerodynamic losses, efficiency and optimum spacing between a rotor and stator in turbomachinery.

  1. Confinement Aquaculture. Final Report.

    ERIC Educational Resources Information Center

    Delaplaine School District, AR.

    The Delaplaine Agriculture Department Confinement Project, begun in June 1988, conducted a confinement aquaculture program by comparing the growth of channel catfish raised in cages in a pond to channel catfish raised in cages in the Black River, Arkansas. The study developed technology that would decrease costs in the domestication of fish, using…

  2. Indoor Confined Feedlots.

    PubMed

    Grooms, Daniel L; Kroll, Lee Anne K

    2015-07-01

    Indoor confined feedlots offer advantages that make them desirable in northern climates where high rainfall and snowfall occur. These facilities increase the risk of certain health risks, including lameness and tail injuries. Closed confinement can also facilitate the rapid spread of infectious disease. Veterinarians can help to manage these health risks by implementing management practices to reduce their occurrence.

  3. Confinement Aquaculture. Final Report.

    ERIC Educational Resources Information Center

    Delaplaine School District, AR.

    The Delaplaine Agriculture Department Confinement Project, begun in June 1988, conducted a confinement aquaculture program by comparing the growth of channel catfish raised in cages in a pond to channel catfish raised in cages in the Black River, Arkansas. The study developed technology that would decrease costs in the domestication of fish, using…

  4. Bright Streaks and Dark Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The south polar region of Mars is covered every year by a layer of carbon dioxide ice. In a region called the 'cryptic terrain,' the ice is translucent and sunlight can penetrate through the ice to warm the surface below.

    The ice layer sublimates (evaporates) from the bottom. The dark fans of dust seen in this image come from the surface below the layer of ice, carried to the top by gas venting from below. The translucent ice is 'visible' by virtue of the effect it has on the tone of the surface below, which would otherwise have the same color and reflectivity as the fans.

    Bright streaks in this image are fresh frost. The CRISM team has identified the composition of these streaks to be carbon dioxide.

    Observation Geometry Image PSP_003113_0940 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 26-Mar-2007. The complete image is centered at -85.8 degrees latitude, 106.0 degrees East longitude. The range to the target site was 244.9 km (153.0 miles). At this distance the image scale is 49.0 cm/pixel (with 2 x 2 binning) so objects 147 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel . The image was taken at a local Mars time of 06:20 PM and the scene is illuminated from the west with a solar incidence angle of 79 degrees, thus the sun was about 11 degrees above the horizon. At a solar longitude of 207.6 degrees, the season on Mars is Northern Autumn.

  5. Bright Streaks and Dark Fans

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The south polar region of Mars is covered every year by a layer of carbon dioxide ice. In a region called the 'cryptic terrain,' the ice is translucent and sunlight can penetrate through the ice to warm the surface below.

    The ice layer sublimates (evaporates) from the bottom. The dark fans of dust seen in this image come from the surface below the layer of ice, carried to the top by gas venting from below. The translucent ice is 'visible' by virtue of the effect it has on the tone of the surface below, which would otherwise have the same color and reflectivity as the fans.

    Bright streaks in this image are fresh frost. The CRISM team has identified the composition of these streaks to be carbon dioxide.

    Observation Geometry Image PSP_003113_0940 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 26-Mar-2007. The complete image is centered at -85.8 degrees latitude, 106.0 degrees East longitude. The range to the target site was 244.9 km (153.0 miles). At this distance the image scale is 49.0 cm/pixel (with 2 x 2 binning) so objects 147 cm across are resolved. The image shown here has been map-projected to 50 cm/pixel . The image was taken at a local Mars time of 06:20 PM and the scene is illuminated from the west with a solar incidence angle of 79 degrees, thus the sun was about 11 degrees above the horizon. At a solar longitude of 207.6 degrees, the season on Mars is Northern Autumn.

  6. Alluvial fans and fan deltas: a guide to exploration for oil and gas

    SciTech Connect

    Fraser, G.S.; Suttner, L.

    1986-01-01

    This volume is a result of a series of lectures presented to an oil company in 1985 and is intended for an audience of explorationists. Material is presented in the order in which an exploration program might proceed in a frontier area. The volume is divided into six chapters that cover definitions and tectonic setting, alluvial-fan morphology, processes and facies on alluvial fans, geomorphic controls, effects of extrinsic controls (chiefly tectonism and climate) on alluvial-fan sequences, and diagenesis. Previously published black-and-white line drawings from studies of modern and ancient fans and fan deltas provide almost all the illustrative material; only one photograph is included, an aerial view of fans in part of Death Valley. The authors emphasize the complexity and variability of fan deposits and their resultant architecture. Although the volume contains a useful review of previous literature, it contains little new material, and it is remarkably lacking subsurface examples and data for a volume intended for the exploration community. In addition, fan deltas receive only brief attention; the overwhelming part of the book is devoted to alluvial fans. The volume will be of interest to those involved in studies of modern and ancient alluvial-fan deposits. 165 references.

  7. School spirits: alcohol and collegiate sports fans.

    PubMed

    Nelson, Toben F; Wechsler, Henry

    2003-01-01

    While studies have addressed alcohol use and related problems among college athletes, little is known about the drinking patterns of non-athletes who are sports fans. This study examines the relationship between alcohol use and interest in collegiate sports on two levels. First, do sports fans in college binge drink more and exhibit more negative alcohol-related outcomes than other students? Second, do colleges with large numbers of sports fans have higher rates of heavy drinking and accompanying secondhand effects affecting other students? The study analyzed the responses of a nationally representative sample of students who completed questionnaires in the spring of 1999 regarding their extracurricular activities and substance use. The responses of 3445 student sports fans were compared to those of 8405 students who were not sports fans. More sports fans drank alcohol, engaged in binge drinking, had a heavy drinking style and reported alcohol-related problems than nonfans. The percentage of sports fans at a school was associated with binge drinking rates and the secondhand effects. The implications for those working with college athletics and for alcohol prevention personnel are discussed.

  8. UHB Engine Fan Broadband Noise Reduction Study

    NASA Technical Reports Server (NTRS)

    Gliebe, Philip R.; Ho, Patrick Y.; Mani, Ramani

    1995-01-01

    A study has been completed to quantify the contribution of fan broadband noise to advanced high bypass turbofan engine system noise levels. The result suggests that reducing fan broadband noise can produce 3 to 4 EPNdB in engine system noise reduction, once the fan tones are eliminated. Further, in conjunction with the elimination of fan tones and an increase in bypass ratio, a potential reduction of 7 to 10 EPNdB in system noise can be achieved. In addition, an initial assessment of engine broadband noise source mechanisms has been made, concluding that the dominant source of fan broadband noise is the interaction of incident inlet boundary layer turbulence with the fan rotor. This source has two contributors, i.e., unsteady life dipole response and steady loading quadrupole response. The quadrupole contribution was found to be the most important component, suggesting that broadband noise reduction can be achieved by the reduction of steady loading field-turbulence field quadrupole interaction. Finally, for a controlled experimental quantification and verification, the study recommends that further broadband noise tests be done on a simulated engine rig, such as the GE Aircraft Engine Universal Propulsion Simulator, rather than testing on an engine statically in an outdoor arena The rig should be capable of generating forward and aft propagating fan noise, and it needs to be tested in a large freejet or a wind tunnel.

  9. Small fan-in is beautiful

    SciTech Connect

    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.

  10. Large Fluvial Fans and Exploration for Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Wilkinson, Murray Justin

    2005-01-01

    A report discusses the geological phenomena known, variously, as modern large (or large modern) fluvial fans or large continental fans, from a perspective of exploring for hydrocarbons. These fans are partial cones of river sediment that spread out to radii of 100 km or more. Heretofore, they have not been much recognized in the geological literature probably because they are difficult to see from the ground. They can, however, be seen in photographs taken by astronauts and on other remotely sensed imagery. Among the topics discussed in the report is the need for research to understand what seems to be an association among fluvial fans, alluvial fans, and hydrocarbon deposits. Included in the report is an abstract that summarizes the global distribution of large modern fluvial fans and a proposal to use that distribution as a guide to understanding paleo-fluvial reservoir systems where oil and gas have formed. Also included is an abstract that summarizes what a continuing mapping project has thus far revealed about the characteristics of large fans that have been found in a variety of geological environments.

  11. Dynamic response of Hovercraft lift fans

    NASA Astrophysics Data System (ADS)

    Moran, D. D.

    1981-08-01

    Hovercraft lift fans are subjected to varying back pressure due to wave action and craft motions when these vehicles are operating in a seaway. The oscillatory back pressure causes the fans to perform dynamically, exhibiting a hysteresis type of response and a corresponding degradation in mean performance. Since Hovercraft motions are influenced by variations in lift fan pressure and discharge, it is important to understand completely the nature of the dynamic performance of lift fans in order to completely solve the Hovercraft seakeeping problem. The present study was performed to determine and classify the instabilities encountered in a centrifugal fan operating against time-varying back pressure. A model-scale experiment was developed in which the fan discharge was directed into a flow-measuring device, terminating in a rotating valve which produced an oscillatory back pressure superimposed upon a mean aerodynamic resistance. Pressure and local velocity were measured as functions of time at several locations in the fan volute. The measurements permitted the identification of rotating (or propagating) stall in the impeller. One cell and two cell configurations were classified and the transient condition connecting these two configurations was observed. The mechanisms which lead to rotating stall in a centrifugal compressor are presented and discussed with specific reference to Hovercraft applications.

  12. Coaxial Compound Helicopter for Confined Urban Operations

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Elmore, Joshua F.; Keen, Ernest B.; Gallaher, Andrew T.; Nunez, Gerardo F.

    2016-01-01

    A rotorcraft was designed for military operations in a confined urban environment. The specifications included major increases in useful load, range, and speed relative current aircraft capabilities, with a size constraint based on the dimensions of urban streets and intersections. Analysis showed that this combination of requirements is best satisfied by a coaxial main-rotor configuration, with lift compounding to off-load the rotors at high speed, and ducted fans under the rotor disk for propulsion. The baseline design is described, and the aircraft performance is summarized for utility, attack, MEDEVAC, and cargo delivery missions. The impact on size and performance is examined for a number of excursions, including lift-offset main rotors. Technology development required to achieve this advance in capability is recommended.

  13. Fan Noise Prediction: Status and Needs

    NASA Technical Reports Server (NTRS)

    Huff, Dennis L.

    1997-01-01

    The prediction of fan noise is an important part to the prediction of overall turbofan engine noise. Advances in computers and better understanding of the flow physics have allowed researchers to compute sound generation from first principles and rely less on empirical correlations. While progress has been made, there are still many aspects of the problem that need to be explored. This paper presents some recent advances in fan noise prediction and suggests areas that still need further development. Fan noise predictions that support the recommendations are taken from existing publications.

  14. Modern and ancient alluvial fan deposits

    SciTech Connect

    Nilsen, T.H.

    1985-01-01

    Understanding the structure and depositional processes of alluvial fans (river outwash deposits) has a special interest for those involved with the exploration of petroleum and many minerals. This collection of facsimile reprints of significant and classical research papers sheds new light on the subject. This reference covers the stratigraphy, sedimentology, and depositional processes of modern and ancient alluvial fans. Geographical areas considered include Arctic Canada, the American Southwest, Australia, Wyoming, Norway, and Spain. It includes a state-of-the-art introduction by the editor along with commentaries on all the papers included, a master author citation index and a subject index, and a chronological listing of early studies of alluvial fans.

  15. Fan Database and Web-tool for Choosing Quieter Spaceflight Fans

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S.; Burnside, Nathan J.

    2007-01-01

    One critical aspect of designing spaceflight hardware is the selection of fans to provide the necessary cooling. And with efforts to minimize cost and the tendancy to be conservative with the amount of cooling provided, it is easy to choose an overpowered fan. One impact of this is that the fan uses more energy than is necessary. But, the more significant impact is that the hardware produces much more acoustic noise than if an optimal fan was chosen. Choosing the right fan for a specific hardware application is no simple task. It requires knowledge of cooling requirements and various fan performance characteristics as well as knowledge of the aerodynamic losses of the hardware in which the fan is to be installed. Knowledge of the acoustic emissions of each fan as a function of operating condition is also required in order to choose a quieter fan for a given design point. The purpose of this paper is to describe a database and design-tool that have been developed to aid spaceflight hardware developers in choosing a fan for their application that is based on aerodynamic performance and reduced acoustic emissions as well. This web-based-tool provides a limited amount of fan-data, provides a method for selecting a fan based on its projected operating point, and also provides a method for comparing and contrasting aerodynamic performance and acoustic data from different fans. Drill-down techniques are used to display details of the spectral noise characteristics of the fan at specific operation conditions. The fan aerodynamic and acoustic data were acquired at Ames Research Center in the Experimental Aero-Physics Branch's Anechoic Chamber. Acoustic data were acquired according to ANSI Standard S12.11-1987, "Method for the Measurement of Noise Emitted by Small Air-Moving Devices." One significant improvement made to this technique included automation that allows for a significant increase in flow-rate resolution. The web-tool was developed at Johnson Space Center and is

  16. Fan Database and Web-tool for Choosing Quieter Spaceflight Fans

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S.; Burnside, Nathan J.

    2007-01-01

    One critical aspect of designing spaceflight hardware is the selection of fans to provide the necessary cooling. And with efforts to minimize cost and the tendancy to be conservative with the amount of cooling provided, it is easy to choose an overpowered fan. One impact of this is that the fan uses more energy than is necessary. But, the more significant impact is that the hardware produces much more acoustic noise than if an optimal fan was chosen. Choosing the right fan for a specific hardware application is no simple task. It requires knowledge of cooling requirements and various fan performance characteristics as well as knowledge of the aerodynamic losses of the hardware in which the fan is to be installed. Knowledge of the acoustic emissions of each fan as a function of operating condition is also required in order to choose a quieter fan for a given design point. The purpose of this paper is to describe a database and design-tool that have been developed to aid spaceflight hardware developers in choosing a fan for their application that is based on aerodynamic performance and reduced acoustic emissions as well. This web-based-tool provides a limited amount of fan-data, provides a method for selecting a fan based on its projected operating point, and also provides a method for comparing and contrasting aerodynamic performance and acoustic data from different fans. Drill-down techniques are used to display details of the spectral noise characteristics of the fan at specific operation conditions. The fan aerodynamic and acoustic data were acquired at Ames Research Center in the Experimental Aero-Physics Branch's Anechoic Chamber. Acoustic data were acquired according to ANSI Standard S12.11-1987, "Method for the Measurement of Noise Emitted by Small Air-Moving Devices." One significant improvement made to this technique included automation that allows for a significant increase in flow-rate resolution. The web-tool was developed at Johnson Space Center and is

  17. The alluvial fan, fan-delta and sublacustrine fan of Paleogene age within Liaohe Rift, Liaoning Province, China

    NASA Astrophysics Data System (ADS)

    Huo, Yan

    1990-07-01

    Liaohe Rift is the Liaoning section of the Tan-Lu fault system, which passes through Bohai Sea and is elongated toward the north. Two main subparallel faults moved violently during the Paleogene in the area, and two columns of asymmetrical depressions stretching in NE-SW direction were formed. The oil reservoirs in the basin of Paleogene age can be classified mainly into three types: (1) alluvial fan, (2) fan-delta, and (3) sublacustrine fan based on the studies of the colour and composition of mudstones, sedimentary structure of sandstones and rhythm of sequences. Variation in tectonic activity caused differences in provenance; the sandbodies therefore have their own characteristics. Based on the above, a sedimentary model for the Liaohe Rift can be established: from the margin toward the centre of the basin, the types of sedimentary facies were respectively alluvial fan, floodplain, fan-delta, subaqueous canyon and sublacustrine fan, fan-delta and sublacustrine fan formed the main facies, and were located on the downfaulted side of the faults, while the floodplain and subaqueous canyon were the transition facies. The greater the concentration of faults, the more intense was their tectonic activity, the greater the sediment supply from the upfaulted blocks and the lower sediment maturity and less well developed are the transition facies. Generally, during lake flooding, the greatest tectonic activity took place at the steep side of the basin. During subaerial sedimentation, the least activity happened along the strike direction of the basin. By using this model, the sedimentary bodies formed in different structural episodes and portion of the basin can be interpreted.

  18. Identification with sports teams by fans of women's sports.

    PubMed

    Nelson, Kelly

    2004-10-01

    Previous studies on why sports fans identify with a particular team have focused on fans of men's sports teams. This study examined why fans favor a particular women's sports team. Based on survey responses from 273 self-identified fans of women's sports, athletes are most frequently cited as the reason for choosing a favorite women's sports team.

  19. 30 CFR 57.8519 - Underground main fan controls.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Underground main fan controls. 57.8519 Section... Ventilation Surface and Underground § 57.8519 Underground main fan controls. All underground main fans shall have controls placed at a suitable protected location remote from the fan and preferably on the...

  20. 30 CFR 57.8518 - Main and booster fans.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main and booster fans. 57.8518 Section 57.8518... and Underground § 57.8518 Main and booster fans. (a) All mine main and booster fans installed and used..., or adjustments. (b) In the event of main or booster fan failure due to a malfunction, accident, power...

  1. 30 CFR 75.311 - Main mine fan operation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... back-up fan system— (1) Only persons necessary to evaluate the effect of the fan stoppage or restart... back-up fan system is used that does not provide the ventilating quantity provided by the main mine fan... fire or other products of combustion are approved in the ventilation plan. (g) If multiple mine...

  2. From Confinement to Superfluidity?

    NASA Astrophysics Data System (ADS)

    Zakharov, V. I.

    2011-04-01

    We describe a unified picture of confining and deconfined phases of Yang-Mills theories in terms of nonperturbative vacuum defects. The confinement is related to condensation of (magnetic) strings. The phase transition at T = Tc is viewed as change of dimensions, 4d → 3d. Namely, all the defects become time oriented. As a result, percolation of strings becomes percolation of 3d trajectories or, in field theoretic language, condensation of a 3d scalar field. The condensation, in turn, might signal superfluidity of the quark-gluon plasma. The notes are mostly a mini-review. A remark on entanglement and confinement is added.

  3. Elastic membranes in confinement

    NASA Astrophysics Data System (ADS)

    Bostwick, Joshua; Miksis, Michael; Davis, Stephen

    2014-11-01

    An elastic membrane stretched between two walls takes a shape defined by its length and the volume of fluid it encloses. Many biological structures, such as cells, mitochondria and DNA, have finer internal structure in which a membrane (or elastic member) is geometrically ``confined'' by another object. We study the shape stability of elastic membranes in a ``confining'' box and introduce repulsive van der Waals forces to prevent the membrane from intersecting the wall. We aim to define the parameter space associated with mitochondria-like deformations. We compare the confined to `unconfined' solutions and show how the structure and stability of the membrane shapes changes with the system parameters.

  4. Mass gap without confinement

    NASA Astrophysics Data System (ADS)

    Faedo, Antón F.; Mateos, David; Pravos, David; Subils, Javier G.

    2017-06-01

    We revisit a one-parameter family of three-dimensional gauge theories with known supergravity duals. We show that three infrared behaviors are possible. For generic values of the parameter, the theories exhibit a mass gap but no confinement, meaning no linear quark-antiquark potential; for one limiting value of the parameter the theory flows to an infrared fixed point; and for another limiting value it exhibits both a mass gap and confinement. Theories close to these limiting values exhibit quasi-conformal and quasi-confining dynamics, respectively. Eleven-dimensional supergravity provides a simple, geometric explanation of these features.

  5. Numerical Analysis for the Air Flow of Cross Flow Fan

    NASA Astrophysics Data System (ADS)

    Sakai, Hirokazu; Tokushge, Satoshi; Ishikawa, Masatoshi; Ishihara, Takuya

    There are many factors for designing the cross flow fan. Therefore, the performance of cross flow fan is not clear yet. We can analyze the transient flow of a cross flow fan using sliding mesh approach. One of the tasks using Computational Fluid Dynamics (CFD) is a way of modeling for analysis heat exchangers with cross flow fan. These tasks are very important for design. The paper has a modeling of heat exchangers and meshing the fan blades. The next tasks, we focus the ability of cross flow fan when we change the geometry of fan blades.

  6. Navy Fan, California Borderland: Growth pattern and depositional processes

    USGS Publications Warehouse

    Normark, W.R.; Piper, D.J.W.

    1984-01-01

    Navy Fan is a Late Pleistocene sand-rich fan prograding into an irregularly shaped basin in the southern California Borderland. The middle fan, characterized by one active and two abandoned 'distributary' channels and associated lobe deposits, at present onlaps part of the basin slope directly opposite from the upper-fan valley, thus dividing the lower-fan/basin-plain regions into two separate parts of different depths. Fine-scale mesotopographic relief on the fan surface and correlation of individual turbidite beds through nearly 40 cores on the middle and lower fan provide data for evaluating the Late Pleistocene and Holocene depositional processes. ?? 1984 Springer-Verlag New York Inc.

  7. 11. EXTERIOR VIEW OF NEW FAN HOUSE LOOKING EAST The ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. EXTERIOR VIEW OF NEW FAN HOUSE LOOKING EAST The airway (on the left) leads from the Baltimore shaft to the New Fan House. The metal housing (center foreground) encases a single entry Duplex Conoidal fan, made by the Buffalo Forge Company. The Duplex Conoidal fan had two parts: a disk fan which drew air up the airway and a centrifugal fan set at a right angle to it which exhausted the air. The engine house (on the right) contains a direct connected Corliss engine. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  8. [Functional status of submariners after short-time submarine raid in the sea].

    PubMed

    Kalmanov, A S; Pisarev, A A; Khankevich, Yu R; Bloshchinskii, I A; Valskii, A V

    2015-10-01

    Short-time sea submarine raids (from a few days to a few weeks), performed during one working cycle, negatively influence on the functional state of the submariners organism. Upon returning to the point of basing the crew involved in the maintenance of the material and performs preparations for further access to the sea. Due to the high workload and lack of time personnel are not held in any correctional and rehabilitation activities, and therefore the time for the next release in the sea functional condition and functional reserves of the body does not have time to fully recover. The transfer of the submarine crew and referral to medical and psychological rehabilitation assumed only after the end of the operating cycle after the crew the task of further voyage. Based on the assessment of the functional systems of the submarine after a short voyage concluded on the need to develop a set of remedial measures for the recovery of submarine crews during inter-cruise period.

  9. Anatomy and growth pattern of Amazon deep-sea fan as revealed by long-range side-scan sonar (GLORIA) and high-resolution seismic studies

    SciTech Connect

    Damuth, J.E.; Flood, R.D.; Kowsmann, R.O.; Belderson, R.H.; Gorini, M.A.

    1988-08-01

    Imaging of the Amazon deep-sea fan with long-range side-scan sonar (GLORIA) has, for the first time, revealed the anatomy, trends, and growth pattern of distributary channels on this fan. Only one channel-levee system was active at any given time and extended from the Amazon Submarine Canyon downslope onto the lower fan (> 4,200 m). Formation of new channel-levee systems occurred when a currently active channel-levee system was cut off and abandoned through avulsion, and a new channel-levee system was established nearby. Through time, successive channel-levee formation and abandonment built two broad levee complexes consisting of groups of overlapping, coalescing segments of channel-levee systems across the present fan surface. These, plus older, now buried levee complexes, indicate that fan growth is radially outward and downslope through development of successive levee complexes. The most striking characteristic of the distributary channels is their intricate, often recurving, meanders with sinuosities of up to 2.5. Cutoffs and abandoned meander loops indicate that the channels migrate laterally through time. Channel bifurcation results predominantly from avulsion when flows breach a channel levee, thereby abandoning the present channel and establishing a new channel-levee segment nearby. No clear evidence of channel branching (i.e., division of a single channel into two active segments) or braiding was observed. 22 figs.

  10. Structure and history of submarine slope failures at the Cape Fear submarine landslide, U.S. Atlantic margin

    NASA Astrophysics Data System (ADS)

    Miller, N. C.; Chaytor, J. D.; Hutchinson, D. R.; Ten Brink, U. S.; Flores, C. H.

    2015-12-01

    New multi-channel seismic (MCS), chirp sub-bottom, and multibeam bathymetry and backscatter data image the Late Pleistocene-Holocene age Cape Fear submarine landslide (CFS) along its complete ~375 km length, from the multiple headwalls at ~2500 m water depth on the slope to the lobate, low-relief toe at ~5400 m water depth. A surficial chaotic mass transport deposit (MTD) filling the failure scar exceeds 100 m in thickness over large sections of the deposit, thinning towards the margins of the slide. Below 5000 m, the CFS truncates the surficial MTD of the Cape Lookout Landslide in several places, indicating that it post-dates the Cape Lookout Landslide. At depth, the MCS data image the edge of the Cape Fear salt diapir and a seismically transparent region that may be associated with fluid flow focused along the edge of the diapir. This potential fluid pathway sits directly beneath the headwalls of the CFS, supporting the hypothesis that the salt diapir is responsible for the failure, either through deformation of sediments during salt emplacement or by focusing of fluids, or both. The MCS data also image several earlier MTDs. These deposits are confined to sediments younger than the early Cenozoic, consistent with interpretations of major canyon cutting in the Eocene and initiation of intense deep and erosive currents in the Late Paleogene. These processes can over-steepen and redistribute slope sediments, enhancing conditions for slope failures and salt diapirism.

  11. Influence of Anchoring on Burial Depth of Submarine Pipelines.

    PubMed

    Zhuang, Yuan; Li, Yang; Su, Wei

    2016-01-01

    Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed.

  12. Prevalence of Helicobacter pylori in United States Navy submarine crews.

    PubMed

    Jackman, R P; Schlichting, C; Carr, W; Dubois, A

    2006-06-01

    Helicobacter pylori prevalence is elevated in German submarine crews and in United States Navy (USN) surface fleet personnel, but H. pylori prevalence in USN submariners was unknown. The goal of the study was to determine the prevalence of H. pylori in the crews of USN nuclear submarines compared to other military personnel and to the general US population. The presence of H. pylori IgG antibodies was determined in serum samples using a commercial ELISA. Only 47 out of 451 submariners (9.4%) were H. pylori positive, which is similar to that of the US general population with a similar level of education. In contrast, H. pylori prevalence is significantly higher in US Army recruits (26%), USN surface fleet personnel (25%), and German diesel submariners (38%). These data demonstrate that submarine service (and by inference activity requiring isolation and close contact, per se) is not a risk factor for H. pylori infection.

  13. Influence of Anchoring on Burial Depth of Submarine Pipelines

    PubMed Central

    Zhuang, Yuan; Li, Yang; Su, Wei

    2016-01-01

    Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed. PMID:27166952

  14. Response analysis of a submarine cable under fault movement

    NASA Astrophysics Data System (ADS)

    Liu, Aiwen

    2009-03-01

    Based on the performance of submarine cables in past earthquakes, an analytical method to determine cable performance under seabed fault movement is proposed in this paper. First, common types of earthquake damage to submarine cables are summarized, which include seabed displacement induced by fault movement, submarine landslides and seabed soil liquefaction, etc. The damage is similar to damage observed to buried pipelines following land earthquakes. The Hengchun earthquake of Dec. 26, 2006 is used as a case study. The M7.2 earthquake occurred in the South China Sea at 20:26 Beijing Time, and caused 14 international submarine cables to sever and break. The results show that the proposed method predicts damage similar to that observed in the Hengchun earthquake. Based on parametric studies of the influence of the water depth and the magnitude of the submarine earthquake, countermeasures to prevent damage to submarine cables are proposed.

  15. Energy efficient engine: fan test hardware detailed design report

    SciTech Connect

    Sullivan, T.J.

    1980-10-01

    A single stage fan and quarter stage booster were designed for the energy efficient engine. The fan has an inlet radius ratio of 0.342 and a specific flow rate of 208.9 Kg/S sq m (42.8 lbm/sec sq ft). The fan rotor has 32 medium aspect ratio (2.597) titanium blades with a partspan shroud at 55% blade height. The design corrected fan tip speed is 411.5 M/S (1350 ft/sec). The quarter stage island splits the total fan flow with approximately 22% of the flow being supercharged by the quarter stage rotor. The fan bypass ratio is 6.8. The core flow total pressure ratio is 1.67 and the fan bypass pressure ratio is 1.65. The design details of the fan and booster blading, and the fan frame and static structure for the fan configuration are presented.

  16. Energy efficient engine: Fan test hardware detailed design report

    NASA Technical Reports Server (NTRS)

    Sullivan, T. J.

    1980-01-01

    A single stage fan and quarter stage booster were designed for the energy efficient engine. The fan has an inlet radius ratio of 0.342 and a specific flow rate of 208.9 Kg/S sq m (42.8 lbm/sec sq ft). The fan rotor has 32 medium aspect ratio (2.597) titanium blades with a partspan shroud at 55% blade height. The design corrected fan tip speed is 411.5 M/S (1350 ft/sec). The quarter stage island splits the total fan flow with approximately 22% of the flow being supercharged by the quarter stage rotor. The fan bypass ratio is 6.8. The core flow total pressure ratio is 1.67 and the fan bypass pressure ratio is 1.65. The design details of the fan and booster blading, and the fan frame and static structure for the fan configuration are presented.

  17. 7. EXTERIOR VIEW OF BALTIMORE FAN HOUSE, AIRWAY, AND HILLMAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. EXTERIOR VIEW OF BALTIMORE FAN HOUSE, AIRWAY, AND HILLMAN FAN HOUSE LOOKING SOUTHEAST The roof of the 1908 Baltimore Fan House is to the left; the doorway opens onto the rear of the metal fan housing. In the immediate foreground is a section of the blast doors installed in the airway directly over the shaft to protect the fans in case of a mine explosion. The sloping airway, to the right, connects with the New Fan House, whose metal updraft chimney is evident in the right background. The engine house of the Hillman Fan House is in the left background with the fan housing and updraft chimney connected. The boiler house stack is in the background. All of the engines in the fan complex were powered by the boiler house. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  18. CF6 jet engine performance improvement: New fan

    NASA Technical Reports Server (NTRS)

    Fasching, W. A.

    1980-01-01

    As part of the NASA sponsored engine component improvement program, and fan package was developed to reduce fuel consumption in current CF6 turbofan aircraft engine. The new fan package consist of an improved fan blade, reduced fan tip clearance due to a fan case stiffener, and a smooth fan casing tip shroud. CF6 engine performance and acoustic tests demonstrated the predicted 1.8% improvement in cruise sfc without an increase in engine noise. Power management thrust/fan speed characteristics were defined. Mechanical and structural integrity was demonstrated in model fan rotor photoelastic stress tests, full-size fan blade bench fatigue tests, and CF6 engine bird ingestion, crosswind, and cyclic endurance tests. The fan was certified in the CF6-500c2/E2 engines and is in commerical service on the Boeing 747-200, Douglas DC-10-30, and Atrbus industrie A300B aircraft.

  19. 16. INTERIOR VIEW OF SUBMARINE SECTION AT 110FOOT LEVEL, ESCAPE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. INTERIOR VIEW OF SUBMARINE SECTION AT 110-FOOT LEVEL, ESCAPE TRAINING TANK, SHOWING LADDER TO ESCAPE TANK, LOOKING SOUTH - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  20. 50. PIPING FOR SUBMARINE SECTION, Y&D No. 107728 Scale 3/8' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. PIPING FOR SUBMARINE SECTION, Y&D No. 107728 Scale 3/8' = 1'; August 26, 1929 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

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

    NASA Technical Reports Server (NTRS)

    Miller, Christopher J. (Technical Monitor); Repp, Russ; Gentile, David; Hanson, David; Chunduru, Srinivas

    2003-01-01

    The primary objective of the Quiet High-Speed Fan (QHSF) program was to develop an advanced high-speed fan design that will achieve a 6 dB reduction in overall fan noise over a baseline configuration while maintaining similar performance. The program applies and validates acoustic, aerodynamic, aeroelastic, and mechanical design tools developed by NASA, US industry, and academia. The successful fan design will be used in an AlliedSignal Engines (AE) advanced regional engine to be marketed in the year 2000 and beyond. This technology is needed to maintain US industry leadership in the regional turbofan engine market.

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

    NASA Technical Reports Server (NTRS)

    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.

  3. Experimental Alluvial Fan Modeling Related to Large Alluvial Fans on Mars

    NASA Astrophysics Data System (ADS)

    Kraal, E. R.; van Dijk, M.; Postma, G.

    2006-12-01

    A population of large alluvial fans has been discovered on Mars. They emanate from crater rims and deposit into crater basins. The build up of such alluvial fans requires a sustained source of flowing surface water. However, the amount of water may vary and that variation can be recorded in variations in fan surface morphology and slope. About half of the alluvial fans on Mars preserve a surface fluvial record (e.g.stream patterns, meanders, cut banks) and the majority have slopes measurable at Mars Orbiter Laser Altimeter (MOLA) resolution. We are conducting experimental modeling of alluvial fan formation using the Eurotank at Utrecht University to understand the relative importance of sediment discharge and pre-existing basin slopes on alluvial fan morphology. The Eurotank Flume Facility contains a flume 5 by 8 meters. The water discharge, sediment discharge, basin structure, and particle size can all be varied. We conduct two experiments simultaneously; the resulting fans are deposited on two 2.5 by 5 meter prepared surfaces with constant slopes of ~0.035 and ~0.045, respectively. Sediment and water discharge are held constant. Results are recorded as a combination of surface images (from video recording of fluvial processes) and digital terrain models (DTM) at a resolution of ~80 microns from photogrammetry (stereo pairs) of the entire fan apron surface. The DTM and photographic results will be integrated with data from previous experiments of fan formation over lower sloping surfaces and the combined experiments will be compared to the Martian fan population. We will compare the experimental formation of surface fluvial features similar to those observed on Mars (e.g. stream patterns) with the goal of ascertaining the amount of fluid (i.e. debris flow vs. fluvial) required to form the Martian alluvial fans. Though we are currently focusing on Martian large alluvial fans, we anticipate that there will be broad applications to many of the fans discovered on Mars

  4. Synchronous and Cogged Fan Belt Performance Assessment

    SciTech Connect

    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.

  5. Supersonic fan engines for military aircraft

    NASA Technical Reports Server (NTRS)

    Franciscus, L. C.

    1983-01-01

    Engine performance and mission studies were performed for turbofan engines with supersonic through-flow fans. A Mach 2.4 CTOL aircraft was used in the study. Two missions were considered: a long range penetrator mission and a long range intercept mission. The supersonic fan engine is compared with an augmented mixed flow turbofan in terms of mission radius for a fixed takeoff gross weight of 75,000 lbm. The mission radius of aircraft powered by supersonic fan engines could be 15 percent longer than aircraft powered with conventional turbofan engines at moderate thrust to gross weight ratios. The climb and acceleration performance of the supersonic fan engines is better than that of the conventional turbofan engines.

  6. Supersonic fan engines for military aircraft

    NASA Technical Reports Server (NTRS)

    Franciscus, L. C.

    1983-01-01

    Engine performance and mission studies were performed for turbofan engines with supersonic through-flow fans. A Mach 2.4 CTOL aircraft was used in the study. Two missions were considered: a long range penetrator mission and a long range intercept mission. The supersonic fan engine is compared with an augmented mixed flow turbofan in terms of mission radius for a fixed takeoff gross weight of 75,000 lbm. The mission radius of aircraft powered by supersonic fan engines could be 15 percent longer than aircraft powered with conventional turbofan engines at moderate thrust to gross weight ratios. The climb and acceleration performance of the supersonic fan engines is better than that of the conventional turbofan engines. Previously announced in STAR as N83-34947

  7. The Laurentian Fan: Sohm Abyssal Plain

    USGS Publications Warehouse

    Piper, D.J.W.; Stow, D.A.V.; Normark, W.R.

    1984-01-01

    The 0.5- to 2-km thick Quaternary Laurentian Fan is built over Tertiary and Mesozoic sediments that rest on oceanic crust. Two 400-km long fan valleys, with asymmetric levees up to 700-m high, lead to an equally long, sandy, lobate basin plain (northern Sohm Abyssal Plain). The muddy distal Sohm Abyssal Plain is a further 400-km long. The sediment supplied to the fan is glacial in origin, and in part results from seismically triggered slumping on the upper continental slope. Sandy turbidity currents, such as the 1929 Grand Banks earthquake event, probably erode the fan-valley floors; but thick muddy turbidity currents build up the high levees. ?? 1984 Springer-Verlag New York Inc.

  8. A method to assess fluvial fan channel networks, with a preliminary application to fans in coastal British Columbia

    NASA Astrophysics Data System (ADS)

    Millard, Thomas Hugh; Hogan, Dan L.; Wilford, David J.; Roberts, Brian

    2010-03-01

    The channel network on a fluvial fan distributes sediment across the fan surface and determines fan development. We present a method to characterize fan channel networks (FCNs) so that the effect of controls (e.g., sediment supply) on the FCN can be evaluated. We then do a preliminary test of the method using three fans in coastal British Columbia. The method uses a set of three measures: 1) the spatial extent of hydrogeomorphic activity, measured as the percentage of the contemporary fan surface area occupied by active channels; 2) the topologic structure, using node counts to measure channel network complexity; and 3) a sediment budget to indicate the proportion of sediment that is stored on the fan, loosely characterized by comparing the second-largest clast size of sediment at the fan apex or intersection point with the second-largest clast at the toe of the fan. These measures were applied to two fan deltas and one partial fan delta in northern Vancouver Island, British Columbia, using channel surveys conducted in 2006 and 2007. All three fans are located within 30 km of each other, have similar climatic, physiographic, and vegetation settings, and have natural channel networks. Each fan has perennial channel flow at the fan apex. Watershed areas range from 19.5 to 35.6 km 2, and contemporary fan areas range from 0.2 to 0.7 km 2. The Melton Relative Relief ratio ranges from 0.24 to 0.30 and none of the fans show evidence of debris floods or debris flows. In addition to testing the efficacy of the FCN measures, we use these fans to explore the question of whether fans in similar geomorphic settings and with similar controls develop similar FCNs. Results show the fans have between 4.7-8.5 % of the contemporary fan surface occupied by the active channel network. Topologic node counts indicate that the two fan deltas have a similar level of channel complexity, with 42-54 nodes in total. The partial fan delta channel network is approximately half as complex, with

  9. Submarine paleoseismology based on turbidite records.

    PubMed

    Goldfinger, Chris

    2011-01-01

    Many of the largest earthquakes are generated at subduction zones or other plate boundary fault systems near enough to the coast that marine environments may record evidence of them. During and shortly after large earthquakes in the coastal and marine environments, a spectrum of evidence may be left behind, mirroring onshore paleoseismic evidence. Shaking or displacement of the seafloor can trigger processes such as turbidity currents, submarine landslides, tsunami (which may be recorded both onshore and offshore), and soft-sediment deformation. Marine sites may also share evidence of fault scarps, colluvial wedges, offset features, and liquefaction or fluid expulsion with their onshore counterparts. This article reviews the use of submarine turbidite deposits for paleoseismology, focuses on the dating and correlation techniques used to establish stratigraphic continuity of marine deposits, and outlines criteria for distinguishing earthquake deposits and the strategies used to acquire suitable samples and data for marine paleoseismology.

  10. Voluminous submarine lava flows from Hawaiian volcanoes

    SciTech Connect

    Holcomb, R.T.; Moore, J.G.; Lipman, P.W.; Belderson, R.H.

    1988-05-01

    The GLORIA long-range sonar imaging system has revealed fields of large lava flows in the Hawaiian Trough east and south of Hawaii in water as deep as 5.5 km. Flows in the most extensive field (110 km long) have erupted from the deep submarine segment of Kilauea's east rift zone. Other flows have been erupted from Loihi and Mauna Loa. This discovery confirms a suspicion, long held from subaerial studies, that voluminous submarine flows are erupted from Hawaiian volcanoes, and it supports an inference that summit calderas repeatedly collapse and fill at intervals of centuries to millenia owing to voluminous eruptions. These extensive flows differ greatly in form from pillow lavas found previously along shallower segments of the rift zones; therefore, revision of concepts of volcano stratigraphy and structure may be required.

  11. Analysis of the Causes and Consequences of Submarine Slope Failure

    DTIC Science & Technology

    1997-09-30

    ANALYSIS OF THE CAUSES AND CONSEQUENCES OF SUBMARINE SLOPE FAILURE Lincoln F. Pratson Institute of Arctic and Alpine Research University of Colorado...and stratigraphy. SCIENTIFIC OBJECTIVES • Use estimates of the state of stress in a submarine slope to constrain the likelihood and potential mode of...analytical solution for the state of stress in two dimensions in a simple, homogeneous, submarine slope; and second, a numerical solution of the state of

  12. Submarine Landslides: What we Know and Where we are Going!

    NASA Astrophysics Data System (ADS)

    Moscardelli, L. G.; Mountjoy, J. J.; Micallef, A.; Strasser, M.; Vanneste, M.; Chaytor, J. D.; Mosher, D.; Krastel, S.; Lo Iacono, C.; Yamada, Y.

    2015-12-01

    Submarine landslides and other gravity-induced movements can disrupt very large areas of continental margins resulting in long-term seafloor morphologic change and multi-scale mass transport deposits (MTDs). Potential consequences of submarine landslides include damage to seabed infrastructure, offshore facilities, as well as generation or enhancement of tsunamis. MTDs are common on the modern seafloor and within the stratigraphic record. Slides, slumps and debris flows can be constituents of MTDs and can co-occur in the same event or depositional unit. Recent research indicates that relationships exist between MTD geological setting, causal mechanisms, and geometries. Quantitative data analysis suggests that MTD morphometric parameters can be used to link these three parameters. Despite many advances in this field, it still remains unclear how to definitively identify pre-conditioning factors and triggers of submarine landslides in modern slopes, and how submarine landslides evolve after initiation. In addition, new questions regarding the interaction between submarine landslides and active marine processes, such as bottom currents and fluid flow, have emerged.One of the mandates of the S4SLIDE (IGCP-640) project, a joint endeavor of UNESCO and IGCP that represents the broad field of submarine landslide research, is to facilitate interactions at an international level among scientists, industry and government representatives to advance our knowledge on a number of outstanding science questions: (i) What is the nature of the interaction between current-controlled sedimentation and submarine landslides? (ii) What role do transient turbulent-laminar flows play in the formation of submarine landslides? (iii) Do climatic variations control the occurrence of submarine landslides? (iv) What is the economic significance of submarine landslides? (v) Do we understand the hazards that submarine landslides pose to the environment and to humans? This presentation will cover

  13. Foreword to the Air Anti-Submarine Warfare Theme

    DTIC Science & Technology

    2014-06-01

    for public release; distribution is unlimited. FOREWORD TO THE AIR ANTI-SUBMARINE WARFARE THEME Air ASW Board: RADM Mike Manazir, Director Air...Mission Programs (Received April 1, 2014) We are honored to introduce the Air Anti-Submarine Warfare (ASW) themed compendium for the Journal of Underwater...reflect upon. Three main themes emerge from the last decade relating to the air community’s positioning relative to anti-submarine warfare: a shift in

  14. Flutter Calculations for an Experimental Fan

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Srivastava, Rakesh; Panovsky, Josef; Keith, Theo G., Jr.; Stefko, George L.

    2003-01-01

    During testing, an experimental forward-swept fan encountered flutter at part-speed conditions. A three-dimensional propulsion aeroelasticity code, based on a computational fluid dynamics (CFD) approach, was used to model the aeroelastic behavior of this fan. This paper describes the flutter calculations and compares the results to the experimental measurements. Results of sensitivity studies are also presented that show the relative importance of different aspects of aeroelastic modeling.

  15. The Advanced Noise Control Fan Baseline Measurements

    NASA Technical Reports Server (NTRS)

    McAllister, Joseph; Loew, Raymond A.; Lauer, Joel T.; Stuliff, Daniel L.

    2009-01-01

    The NASA Glenn Research Center s (NASA Glenn) Advanced Noise Control Fan (ANCF) was developed in the early 1990s to provide a convenient test bed to measure and understand fan-generated acoustics, duct propagation, and radiation to the farfield. As part of a complete upgrade, current baseline and acoustic measurements were documented. Extensive in-duct, farfield acoustic, and flow field measurements are reported. This is a follow-on paper to documenting the operating description of the ANCF.

  16. Altitude Wind Tunnel Drive Fan being Assembled

    NASA Image and Video Library

    1943-07-21

    National Advisory Committee for Aeronautics (NACA) engineers assembled the Altitude Wind Tunnel’s (AWT) large wooden drive fan inside the hangar at the Aircraft Engine Research Laboratory. When it was built at the in the early 1940s the AWT was among the most complex test facilities ever designed. It was the first wind tunnel capable of operating full-scale engines under realistic flight conditions. This simulation included the reduction of air temperature, a decrease in air pressure, and the creation of an airstream velocity of up to 500 miles per hour. The AWT was constructed in 1942 and 1943. This photograph shows NACA engineers Lou Hermann and Jack Aust assembling the tunnel’s drive fan inside the hangar. The 12-bladed, 31-foot-diameter spruce wood fan would soon be installed inside the wind tunnel to create the high-speed airflow. This massive propeller was designed and constructed by the engine lab's design team at Langley Field. John Breisch, a Langley technician with several years of wind tunnel installation experience, arrived in Cleveland at the time of this photograph to supervise the fan assembly inside the hangar. He would return several weeks later to oversee the actual installation in the tunnel. The fan was driven at 410 revolutions per minute by an 18,000-horsepower General Electric induction motor that was located in the rear corner of the Exhauster Building. An extension shaft connected the motor to the fan. A bronze screen protected the fan against damage from failed engine parts sailing through the tunnel. Despite this screen the blades did become worn or cracked over time and had to be replaced. An entire new fan was installed in 1951.

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

    NASA Astrophysics Data System (ADS)

    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 < 10°, however, they range from horizontal to near vertical. Individual strata display significant changes in depositional dip, beds pinch and swell, and some are completely truncated. Centimeter to meter scale terrace mounds exhibit the common stair-step morphology. As a consequence of vertical accretion in the pools, terrace mounds morphed into sloping fans. The travertine is composed of a variety of commonly reported constituents, i.e., centimeter thick laminae of bacterial shrubs and oncoids, foam 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

  18. Notebook on Nonacoustic Detection of Submarines

    DTIC Science & Technology

    1980-11-12

    6.1.2.1 ( Overhauser Effect (U) ...................................... . 6.1.2.2 ( ) Two·Photon Interactions (U...hydrophone) sonobuoy and a stationary magnetometer (e.g .• in a magnebuoy) are point (iero-dimens1onal) sensors whicn, of themselves. have no outreach...capability. {The submarine-generated fields must come to them.) A magnetometer in a moving aircraft may be considered as operating in one dimension. witti

  19. SSN 774 Virginia Class Submarine (SSN 774)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-516 SSN 774 Virginia Class Submarine (SSN 774) As of FY 2017 President’s Budget Defense...Estimate RDT&E - Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined TY...including three Extended Drydocking Selected Restricted Availabilities (EDSRAs) and one Depot Maintenance Period (DMP) scheduled and planned

  20. Nuclear Electric Magnetohydrodynamic Propulsion for Submarine

    DTIC Science & Technology

    1989-05-01

    The selection of High Temperature Gas Reactor (HTGR) and Liquid-Metal Fast Breeder Reactor ( LMFBR ) was based on the combined merits of safety...150 Nozzle-Separator-Diffuser 5-3 Block Diagram of the Rotary Inverter 153 System 5-4 (a) HTGR with Closed-Cycle Gas Turbine 158 (b) LMFBR with Closed...Sodium Cooled Reactor Subsystem 137 Performance -i1- 4-8 MHD Submarine Powered by LMFBR 139 Performance Summary 5-1 Cryogenic Characteristics of

  1. Polymer Crystallization under Confinement

    NASA Astrophysics Data System (ADS)

    Floudas, George

    Recent efforts indicated that polymer crystallization under confinement can be substantially different from the bulk. This can have important technological applications for the design of polymeric nanofibers with tunable mechanical strength, processability and optical clarity. However, the question of how, why and when polymers crystallize under confinement is not fully answered. Important studies of polymer crystallization confined to droplets and within the spherical nanodomains of block copolymers emphasized the interplay between heterogeneous and homogeneous nucleation. Herein we report on recent studies1-5 of polymer crystallization under hard confinement provided by model self-ordered AAO nanopores. Important open questions here are on the type of nucleation (homogeneous vs. heterogeneous), the size of critical nucleus, the crystal orientation and the possibility to control the overall crystallinity. Providing answers to these questions is of technological relevance for the understanding of nanocomposites containing semicrystalline polymers. In collaboration with Y. Suzuki, H. Duran, M. Steinhart, H.-J. Butt.

  2. Contamination potential of nitrogen compounds in the heterogeneous aquifers of the Choushui River alluvial fan, Taiwan.

    PubMed

    Jang, Cheng-Shin; Liu, Chen-Wuing

    2005-10-01

    This study aimed to analyze the contamination potential associated with the reactive transport of nitrate-N and ammonium-N in the Choushui River alluvial fan, Taiwan and to evaluate a risk region in developing a groundwater protection policy in 2021. In this area, an aquifer redox sequence provided a good understanding of the spatial distributions of nitrate-N and ammonium-N and of aerobic and anaerobic environments. Equiprobable hydraulic conductivity (K) fields reproduced by geostatistical methods characterized the spatial uncertainty of contaminant transport in the heterogeneous aquifer. Nitrogen contamination potential fronts for high and low threshold concentrations based on a 95% risk probability were used to assess different levels of risk. The simulated result reveals that the spatial uncertainty of highly heterogeneous K fields governs the contamination potential assessment of the nitrogen compounds along the regional flow directions. The contamination potential of nitrate-N is more uncertain than that for ammonium-N. The high nitrate-N concentrations (> or =3 mg/L) are prevalent in the aerobic environment. The low concentration nitrate-N plumes (0.5-3 mg/L) gradually migrate to the mid-fan area and to a maximum distance of 15 km from the aerobic region. The nitrate-N plumes pose a potential human health risk in the aerobic and anaerobic environments. The ammonium-N plumes remain stably confined to the distal-fan and partial mid-fan areas.

  3. Contamination potential of nitrogen compounds in the heterogeneous aquifers of the Choushui River alluvial fan, Taiwan

    NASA Astrophysics Data System (ADS)

    Jang, Cheng-Shin; Liu, Chen-Wuing

    2005-10-01

    This study aimed to analyze the contamination potential associated with the reactive transport of nitrate-N and ammonium-N in the Choushui River alluvial fan, Taiwan and to evaluate a risk region in developing a groundwater protection policy in 2021. In this area, an aquifer redox sequence provided a good understanding of the spatial distributions of nitrate-N and ammonium-N and of aerobic and anaerobic environments. Equiprobable hydraulic conductivity ( K) fields reproduced by geostatistical methods characterized the spatial uncertainty of contaminant transport in the heterogeneous aquifer. Nitrogen contamination potential fronts for high and low threshold concentrations based on a 95% risk probability were used to assess different levels of risk. The simulated result reveals that the spatial uncertainty of highly heterogeneous K fields governs the contamination potential assessment of the nitrogen compounds along the regional flow directions. The contamination potential of nitrate-N is more uncertain than that for ammonium-N. The high nitrate-N concentrations (≧ 3 mg/L) are prevalent in the aerobic environment. The low concentration nitrate-N plumes (0.5-3 mg/L) gradually migrate to the mid-fan area and to a maximum distance of 15 km from the aerobic region. The nitrate-N plumes pose a potential human health risk in the aerobic and anaerobic environments. The ammonium-N plumes remain stably confined to the distal-fan and partial mid-fan areas.

  4. Confinement and the Pomeron

    SciTech Connect

    White, A.R.

    1989-09-25

    The importance of confinement for obtaining a unitary high-energy limit for QCD is discussed. Minijets'' are argued to build up non-unitary behavior{endash}when k{sub T} {gt} {Lambda} is imposed. For minijets to mix with low k{sub T} Pomeron Field Theory describing confinement, and give consistent asymptotic behavior, new quarks'' must enter the theory above the minijet transverse momentum scale. The Critical Pomeron is the resulting high-energy limit. 22 refs.

  5. Radiated noise of ducted fans

    NASA Technical Reports Server (NTRS)

    Eversman, Walter

    1992-01-01

    The differences in the radiated acoustic fields of ducted and unducted propellers of the same thrust operating under similar conditions are investigated. An FEM model is created for the generation, propagation, and radiation of steady, rotor alone noise and exit guide vane interaction noise of a ducted fan. For a specified number of blades, angular mode harmonic, and rotor angular velocity, the acoustic field is described in a cylindrical coordinate system reduced to only the axial and radial directions. It is found that, contrary to the usual understanding of the Tyler and Sofrin (1962) result, supersonic tip speed rotor noise can be cut off if the tip Mach number is only slightly in excess of unity and if the number of blades is relatively small. If there are many blades, the fundamental angular mode number is large, and the Tyler and Sofrin result for thin annuli becomes more relevant. Shrouding of subsonic tip speed propellers is a very effective means of controlling rotor alone noise.

  6. Radiated noise of ducted fans

    NASA Astrophysics Data System (ADS)

    Eversman, Walter

    The differences in the radiated acoustic fields of ducted and unducted propellers of the same thrust operating under similar conditions are investigated. An FEM model is created for the generation, propagation, and radiation of steady, rotor alone noise and exit guide vane interaction noise of a ducted fan. For a specified number of blades, angular mode harmonic, and rotor angular velocity, the acoustic field is described in a cylindrical coordinate system reduced to only the axial and radial directions. It is found that, contrary to the usual understanding of the Tyler and Sofrin (1962) result, supersonic tip speed rotor noise can be cut off if the tip Mach number is only slightly in excess of unity and if the number of blades is relatively small. If there are many blades, the fundamental angular mode number is large, and the Tyler and Sofrin result for thin annuli becomes more relevant. Shrouding of subsonic tip speed propellers is a very effective means of controlling rotor alone noise.

  7. Radiated noise of ducted fans

    NASA Technical Reports Server (NTRS)

    Eversman, Walter

    1992-01-01

    The differences in the radiated acoustic fields of ducted and unducted propellers of the same thrust operating under similar conditions are investigated. An FEM model is created for the generation, propagation, and radiation of steady, rotor alone noise and exit guide vane interaction noise of a ducted fan. For a specified number of blades, angular mode harmonic, and rotor angular velocity, the acoustic field is described in a cylindrical coordinate system reduced to only the axial and radial directions. It is found that, contrary to the usual understanding of the Tyler and Sofrin (1962) result, supersonic tip speed rotor noise can be cut off if the tip Mach number is only slightly in excess of unity and if the number of blades is relatively small. If there are many blades, the fundamental angular mode number is large, and the Tyler and Sofrin result for thin annuli becomes more relevant. Shrouding of subsonic tip speed propellers is a very effective means of controlling rotor alone noise.

  8. Submarine tower escape decompression sickness risk estimation.

    PubMed

    Loveman, G A M; Seddon, E M; Thacker, J C; Stansfield, M R; Jurd, K M

    2014-01-01

    Actions to enhance survival in a distressed submarine (DISSUB) scenario may be guided in part by knowledge of the likely risk of decompression sickness (DCS) should the crew attempt tower escape. A mathematical model for DCS risk estimation has been calibrated against DCS outcome data from 3,738 exposures of either men or goats to raised pressure. Body mass was used to scale DCS risk. The calibration data included more than 1,000 actual or simulated submarine escape exposures and no exposures with substantial staged decompression. Cases of pulmonary barotrauma were removed from the calibration data. The calibrated model was used to estimate the likelihood of DCS occurrence following submarine escape from the United Kingdom Royal Navy tower escape system. Where internal DISSUB pressure remains at - 0.1 MPa, escape from DISSUB depths < 200 meters is estimated to have DCS risk < 6%. Saturation at raised DISSUB pressure markedly increases risk, with > 60% DCS risk predicted for a 200-meter escape from saturation at 0.21 MPa. Using the calibrated model to predict DCS for direct ascent from saturation gives similar risk estimates to other published models.

  9. Fusion, magnetic confinement

    SciTech Connect

    Berk, H.L.

    1992-08-06

    An overview is presented of the principles of magnetic confinement of plasmas for the purpose of achieving controlled fusion conditions. Sec. 1 discusses the different nuclear fusion reactions which can be exploited in prospective fusion reactors and explains why special technologies need to be developed for the supply of tritium or {sup 3}He, the probable fuels. In Sec. 2 the Lawson condition, a criterion that is a measure of the quality of confinement relative to achieving fusion conditions, is explained. In Sec. 3 fluid equations are used to describe plasma confinement. Specific confinement configurations are considered. In Sec. 4 the orbits of particle sin magneti and electric fields are discussed. In Sec. 5 stability considerations are discussed. It is noted that confinement systems usually need to satisfy stability constraints imposed by ideal magnetohydrodynamic (MHD) theory. The paper culminates with a summary of experimental progress in magnetic confinement. Present experiments in tokamaks have reached the point that the conditions necessary to achieve fusion are being satisfied.

  10. Fusion, magnetic confinement

    SciTech Connect

    Berk, H.L.

    1992-08-06

    An overview is presented of the principles of magnetic confinement of plasmas for the purpose of achieving controlled fusion conditions. Sec. 1 discusses the different nuclear fusion reactions which can be exploited in prospective fusion reactors and explains why special technologies need to be developed for the supply of tritium or {sup 3}He, the probable fuels. In Sec. 2 the Lawson condition, a criterion that is a measure of the quality of confinement relative to achieving fusion conditions, is explained. In Sec. 3 fluid equations are used to describe plasma confinement. Specific confinement configurations are considered. In Sec. 4 the orbits of particle sin magneti and electric fields are discussed. In Sec. 5 stability considerations are discussed. It is noted that confinement systems usually need to satisfy stability constraints imposed by ideal magnetohydrodynamic (MHD) theory. The paper culminates with a summary of experimental progress in magnetic confinement. Present experiments in tokamaks have reached the point that the conditions necessary to achieve fusion are being satisfied.

  11. Aerodynamic characteristics of a large scale lift fan transport model with podded fans forward and lift cruise fans mounted above the wing

    NASA Technical Reports Server (NTRS)

    Kirk, J. V.; Dickinson, S. O.; Hall, L. P.; Coffman, M. G.

    1972-01-01

    The aerodynamic characteristics of a large scale V/STOL transport model powered by tip-turbine driven lift fans were investigated. The model had four fans; the forward fans were mounted in pods forward of the wing at midsemispan. The aft fans were placed in cruise nacelles behind and above the wing. A cascade of variable camber exit louvers was placed behind each of the lift-cruise fans to turn the fan flow in the lift direction for hover and transition to wing supported flight. The wing of the model was mounted above the fuselage, had an aspect ratio of 5.8, sweepback of 35 deg at the quarter chord line and a taper ratio of 0.3. Various configurations of the model were tested to explore the transition speed range. Fan performance, turning effectiveness of the variable camber exit louvers, longitudinal and lateral-directional characteristics with fan operation in crossflow are presented.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. A Submarine Perspective on Hawaiian Volcanoes

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Postwar improvements in navigation, sonar-based mapping, and submarine photography enabled the development of bathymetric maps, which revealed submarine morphologic features that could be dredged or explored and sampled with a new generation of manned and unmanned submersibles. The maps revealed debris fields from giant landslides, the great extent of rift zones radiating from volcanic centers, and two previously unknown submarine volcanoes named Mahukona and Loihi, the youngest Hawaiian volcano. About 70 major landslides cover half the flanks of the Hawaiian Ridge out to Midway Island. Some of the landslides attain lengths of 200 km and have volumes exceeding 5,000 km3. More recent higher resolution bathymetry and sidescan data reveal that many submarine eruptions construct circular, flat-topped, monogenetic cones; that large fields of young strongly alkalic lava flows, such as the North Arch and South Arch lava fields, erupt on the seafloor within several hundred km of the islands; and that alkalic lavas erupt during the shield stage on Kilauea and Mauna Loa. The North Arch flow field covers about 24,000 km2, has an estimated volume between about 1000 and 1250 km3, has flows as long as 108 km, and erupted from over 100 vents. The source and melting mechanisms for their production is still debated. The maps also displayed stair-step terraces, mostly constructed of drowned coral reefs, which form during early rapid subsidence of the volcanoes during periods of oscillating sea level. The combination of scuba and underwater photography facilitated the first motion pictures of the mechanism of formation of pillow lava in shallow water offshore Kilauea. The age progression known from the main islands was extended westward along the Hawaiian Ridge past Midway Island, around a bend in the chain and northward along the Emperor Seamounts. Radiometric dating of dredged samples from these submarine volcanoes show that the magma source that built the chain has been active for

  14. 75 FR 79952 - Airworthiness Directives; DASSAULT AVIATION Model Falcon 10 Airplanes; Model FAN JET FALCON, FAN...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-21

    ... Model Falcon 10 Airplanes; Model FAN JET FALCON, FAN JET FALCON SERIES C, D, E, F, and G Airplanes; Model MYSTERE-FALCON 200 Airplanes; Model MYSTERE-FALCON 20-C5, 20-D5, 20-E5, and 20-F5 Airplanes; Model FALCON 2000 and FALCON 2000EX Airplanes; and Model MYSTERE-FALCON 50 and MYSTERE-FALCON 900...

  15. HEPA Filter Differential Pressure Fan Interlock System Functional Requirements and Technical Design Criteria

    SciTech Connect

    TUCK, J.A.

    2000-05-11

    Double-shell tanks (DSTs) and Double Contained Receiver Tanks (DCRTs) are actively ventilated, along with certain single-shell tanks (SSTs) and other RPP facilities. The exhaust air stream on a typical primary ventilation system is drawn through two stages of high-efficiency particulate air (HEPA) filtration to ensure confinement of airborne radioactive materials. Active ventilation exhaust stacks require a stack CAM interlock to detect releases from postulated accidents, and to shut down the exhaust fan when high radiation levels are detected in the stack airstream. The stack CAM interlock is credited as a mitigating control to stop continued unfiltered radiological and toxicological discharges from the stack, which may result from an accident involving failure of a HEPA filter. This document defines the initial technical design baseline for a HEPA filter AP fan interlock system.

  16. Sedimentary processes of the lower Monterey Fan channel and channel-mouth lobe

    USGS Publications Warehouse

    Klaucke, I.; Masson, D.G.; Kenyon, Neil H.; Gardner, J.V.

    2004-01-01

    The distribution of deposits, sediment transport pathways and processes on the lower Monterey Fan channel and channel-mouth lobe (CML) are studied through the integration of GLORIA and TOBI sidescan sonar data with 7-kHz subbottom profiler records and sediment cores for ground-truthing. The lower Monterey channel is characterised by an up to 30-m-deep channel with poorly developed levees and alternating muddy and silty muddy overbank deposits. The channel is discontinuous, disappearing where gradients are less than about 1:350. Ground-truthing of the large CML shows that the entire CML is characterised by widespread deposits of generally fine sand, with coarser sand at the base of turbidites. Sand is particularly concentrated in finger-like areas of low-backscatter intensity and is interpreted as the result of non-turbulent sediment-gravity flows depositing metres thick massive, fine sand. TOBI sidescan sonar data reveal recent erosional features in the form of scours, secondary channels, large flow slides, and trains of blocks at the distal end of the CML. Erosion is probably related to increasing gradient as the CML approaches Murray Fracture zone and to differential loading of sandy submarine fan deposits onto pelagic clays. Reworking of older flow slides by sediment transport processes on the lobe produces trains of blocks that are several metres in diameter and aligned parallel to the flow direction. ?? 2004 Elsevier B.V. All rights reserved.

  17. Fan Acoustic Issues in the NASA Space Flight Experience

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S.; Goodman, Jerry

    2008-01-01

    Emphasis needs to be placed on choosing quiet fans compatible with systems design and specifications that control spec levels: a) Sound power; b) Choose quiet fan or plan to quiet it, early in program; c) Plan early verification that fan source allocations are met. Airborne noise: a) System design should function/play together with fans used (flow passages, restrictions, bends, expansions & contractions, and acoustics) vs. fan speed understood (nominal, worst case, & unplanned variances); b) Fan inlets treated, as required; c) Fan Outlets treated, as required; d) Ducted system inlets are outlets designed for acoustic compliance compatibility & designed so some late required modifications can be made without significant impacts. Structure Borne Noise: a) Structure borne noise dealt with as part of fan package or installation; b) Duct attachments and lines isolated. Case Radiated Noise: - Treatment added as much as possible to fan package (see example).

  18. Simulations of Enhanced Confinement

    NASA Astrophysics Data System (ADS)

    Dorland, W.; Kotschenreuther, M.; Liu, Q. P.; Jones, C. S.; Beer, M. A.; Hammett, G. W.

    1996-11-01

    Most existing tokamaks routinely achieve enhanced confinement regimes. Designs for new, larger tokamaks therefore are typically predicated upon reliable enhanced confinement performance. However, most enhanced confinement regimes rely (to some degree) upon sheared E×B flows to stabilize the turbulence that otherwise limits the confinement. For example, the pedestal H-mode transport barrier is typically attributed to shear stabilization [Biglari, Diamond and Terry, Phys. Fl. B, 2 1 (1990)]. Unfortunately, it is easily shown that sheared E×B stabilization of microinstabilities such as the ITG mode does not scale favorably with machine size. Here, using nonlinear gyrofluid simulations in general geometry, we attempt to quantify the confinement enhancement that can be expected from velocity shear stabilization for conventional reactor plasmas. We also consider other microinstability stabilization mechanisms(See related presentations by Beer, Kotschenreuther, Manickam, and Ramos, this conference.) (strong density peaking, Shafranov shift stabilization, dots) and unconventional reactor configurations.^2 Experimental datasets from JET, DIII-D, C-Mod and TFTR are analyzed, and ITER operation is considered.

  19. Holocene sedimentation history of the major fan valleys of Monterey fan

    USGS Publications Warehouse

    Hess, G.R.; Normark, W.R.

    1976-01-01

    There are three major fan valleys on upper Monterey fan. Deep-tow geophysical profiles and 40 sediment cores provide the basis for evaluation of the sedimentation histories of these valleys. Monterey fan valley leads from Monterey canyon to a major suprafan and is bounded by levees that crest more than 400 m above the valley floor. The valley passes through a large z-bend or meander. Monterey East fan valley joins Monterey fan valley at the meander at about 150 m above the valley floor, and marks an earlier position of the lower Monterey fan valley. Ascension valley, a hanging contributary to the Monterey fan valley, appears to have once been the shoreward head of the lower part of the present Monterey fan valley. The relief of Monterey fan valley appears from deep-tow profiles to be erosional. The valley is floored with sand. Holocene turbidity currents do not overtop the levees 400 m above the valley floor, but do at times overflow and transport sand into Monterey East valley, producing a sandy floor. An 1100 m by 300 m dune field was observed on side scan sonar in Monterey East valley. Ascension fan valley was floored with sand during glacial intervals of lowered sea level, then was cut off from its sand source as sea level rose. A narrow (500 m), erosional, meandering channel was incised into the flat valley floor; the relief features otherwise appear depositional, with a hummocky topography perhaps produced in the manner of a braided riverbed. The sand is mantled by about 6 m of probable Holocene mud. Hummocky relief on the back side of the northwestern levees of both Ascension and Monterey valleys is characteristic of many turbidite valleys in the northeast Pacific. The hummocky topography is produced by dune-like features that migrate toward levee crests during growth. ?? 1976.

  20. Confined Brownian ratchets.

    PubMed

    Malgaretti, Paolo; Pagonabarraga, Ignacio; Rubi, J Miguel

    2013-05-21

    We analyze the dynamics of Brownian ratchets in a confined environment. The motion of the particles is described by a Fick-Jakobs kinetic equation in which the presence of boundaries is modeled by means of an entropic potential. The cases of a flashing ratchet, a two-state model, and a ratchet under the influence of a temperature gradient are analyzed in detail. We show the emergence of a strong cooperativity between the inherent rectification of the ratchet mechanism and the entropic bias of the fluctuations caused by spatial confinement. Net particle transport may take place in situations where none of those mechanisms leads to rectification when acting individually. The combined rectification mechanisms may lead to bidirectional transport and to new routes to segregation phenomena. Confined Brownian ratchets could be used to control transport in mesostructures and to engineer new and more efficient devices for transport at the nanoscale.

  1. Confined Brownian ratchets

    NASA Astrophysics Data System (ADS)

    Malgaretti, Paolo; Pagonabarraga, Ignacio; Rubi, J. Miguel

    2013-05-01

    We analyze the dynamics of Brownian ratchets in a confined environment. The motion of the particles is described by a Fick-Jakobs kinetic equation in which the presence of boundaries is modeled by means of an entropic potential. The cases of a flashing ratchet, a two-state model, and a ratchet under the influence of a temperature gradient are analyzed in detail. We show the emergence of a strong cooperativity between the inherent rectification of the ratchet mechanism and the entropic bias of the fluctuations caused by spatial confinement. Net particle transport may take place in situations where none of those mechanisms leads to rectification when acting individually. The combined rectification mechanisms may lead to bidirectional transport and to new routes to segregation phenomena. Confined Brownian ratchets could be used to control transport in mesostructures and to engineer new and more efficient devices for transport at the nanoscale.

  2. Characterisation and modelling of washover fans

    USGS Publications Warehouse

    Donnelly, Chantal; Sallenger, Asbury H.

    2007-01-01

    Pre- and post-storm topography and aerial photography, collected in regions where new washover fans were formed, were studied to determine the extent of morphologic, vegetative and anthropogenic control on washover shape and extent. When overwash is funnelled through a gap in a dune ridge and then spreads laterally on the back barrier, decelerating and depositing sediment, it forms washover fans. Fans were shown to primarily occur at pre-existing gaps in the foredune. During overwash, these gaps, or overwash throats, widened and deepened. The shape and extent of the fan was shown to depend on not only the pre-storm topography, but also the existence of beach tracks, roads and other anthropogenic influences and vegetation. The cross-shore overwash profile change model by Larson et al. and Donnelly et al. was modified to include pre-storm throat widths and a lateral spreading angle estimated from the pre-storm topography as inputs and tested using cross-shore profiles through the fan centres. These new inputs make the model more generalised, such that the calibrated model is applicable to a wider range of cross-shore profiles.

  3. Impact resistance of composite fan blades

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Results are presented of a program to determine the impact resistance of composite fan blades subjected to foreign object damage (FOD) while operating under conditions simulating a short take-off and landing (STOL) engine at takeoff. The full-scale TF39 first-stage fan blade was chosen as the base design for the demonstration component since its configuration and operating tip speeds are similar to a typical STOL fan blade several composite configurations had already been designed and evaluated under previous programs. The first portion of the program was devoted toward fabricating and testing high impact resistant, aerodynamically acceptable composite blades which utilized only a single material system in any given blade. In order to increase the blade impact capability beyond this point, several mixed material (hybrid) designs were investigated using S-glass and Kevlar as well as boron and graphite fibers. These hybrid composite blades showed a marked improvement in resistance to bird impact over those blades made of a single composite material. The work conducted under this program has demonstrated substantial improvement in composite fan blades with respect to FOD resistance and has indicated that the hybrid design concept, which utilizes different types of fibers in various portions of a fan blade design depending on the particular requirements of the different areas and the characteristics of the different fibers involved, shows a significant improvement over those designs utilizing only one material system.

  4. 32 CFR 707.7 - Submarine identification light.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 5 2014-07-01 2014-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all around...

  5. Detail of conning tower atop the submarine. Note the wire ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of conning tower atop the submarine. Note the wire rope wrapped around the base of the tower, which may have been used in an attempt to pull the submarine offshore. - Sub Marine Explorer, Located along the beach of Isla San Telmo, Pearl Islands, Isla San Telmo, Former Panama Canal Zone, CZ

  6. 32 CFR 707.7 - Submarine identification light.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all...

  7. 32 CFR 707.7 - Submarine identification light.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 5 2013-07-01 2013-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all...

  8. 32 CFR 707.7 - Submarine identification light.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 5 2011-07-01 2011-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all...

  9. 32 CFR 707.7 - Submarine identification light.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 5 2012-07-01 2012-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all...

  10. At Periscope Depth: Exploring Submarine Proliferation In Southeast Asia

    DTIC Science & Technology

    2015-09-01

    deterrence, enforcement, prestige, or a combination of the three? This thesis compared the case studies of Indonesia, Malaysia , Singapore, and...rationales for purchasing submarines. Indonesia, Malaysia , and Singapore likely purchased submarines for deterrence and enforcement, and Vietnam for...combination of the three? This thesis compared the case studies of Indonesia, Malaysia , Singapore, and Vietnam, analyzed statements made by government and

  11. Three dimensional boundary layers on submarine conning towers and rudders

    NASA Astrophysics Data System (ADS)

    Gleyzes, C.

    1988-01-01

    Solutions for the definition of grids adapted to the calculation of three-dimensional boundary layers on submarine conning towers and on submarine rudders and fins are described. The particular geometry of such bodies (oblique shaped hull, curved fins) required special adaptations. The grids were verified on examples from a test basin.

  12. 47 CFR 32.2424 - Submarine & deep sea cable.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2424 Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... cost of optical fiber cable and other associated material used in constructing a physical path for the...

  13. Displaying Uncertainty: A Comparison Between Submarine Subject Matter Experts

    DTIC Science & Technology

    2007-03-01

    known as the “submarine capital of the world” and is the home for many of the schools relating to the submarine service. The administering officer for...and Woods, D. D. (1988). Aiding Human Performance: I. Cognitive Analysis, Le Travail Humain 51(1), 39-64. Roth, E. M., Patterson, E. S., and Mumaw

  14. Design Guidelines for Quiet Fans and Pumps for Space Vehicles

    NASA Technical Reports Server (NTRS)

    Lovell, John S.; Magliozzi, Bernard

    2008-01-01

    This document presents guidelines for the design of quiet fans and pumps of the class used on space vehicles. A simple procedure is presented for the prediction of fan noise over the meaningful frequency spectrum. A section also presents general design criteria for axial flow fans, squirrel cage fans, centrifugal fans, and centrifugal pumps. The basis for this report is an experimental program conducted by Hamilton Standard under NASA Contract NAS 9-12457. The derivations of the noise predicting methods used in this document are explained in Hamilton Standard Report SVHSER 6183, "Fan and Pump Noise Control," dated May 1973 (6).

  15. 10. EXTERIOR VIEW OF STONE RETAINING WALL, AIRWAY, BALTIMORE FAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. EXTERIOR VIEW OF STONE RETAINING WALL, AIRWAY, BALTIMORE FAN HOUSE AND HILLMAN FAN HOUSE LOOKING EAST The stone retaining wall encloses a pit which may have been the original site of the Hillman Fan House steam engine. The concrete foundations in the left foreground are more recent (c. 1930) additions which may be supports for a porch or stairway. The sloping airshaft, in the middle ground, connected the Baltimore shaft to the New Fan House (not shown) and Hillman Fan House in the background. The Hillman engine house is on the left. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  16. 22. INTERIOR VIEW OF NEW FAN HOUSE UPSHAFT CHIMNEY LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. INTERIOR VIEW OF NEW FAN HOUSE UPSHAFT CHIMNEY LOOKING WEST The Duplex Conoidal Fan is a single entry disk fan (see PA 61-21 and PA 61-22) which drew air from the No. 4 (Baltimore) shaft up the air-way through the cone, seen on the right, into the centrifugal fan, pictured here. The curved metal blades forced the air from the center of the fan to the tips of the blades and out the sheet metal exhaust chimney. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  17. Prodigious submarine landslides on the Hawaiian Ridge

    NASA Astrophysics Data System (ADS)

    Moore, J. G.; Clague, D. A.; Holcomb, R. T.; Lipman, P. W.; Normark, W. R.; Torresan, M. E.

    1989-12-01

    The extensive area covered by major submarine mass wasting deposits on or near the Hawaiian Ridge has been delimited by systematic mapping of the Hawaiian exclusive economic zone using the side-looking sonar system GLORIA. These surveys show that slumps and debris avalanche deposits are exposed over about 100,000 km2 of the ridge and adjacent seafloor from Kauai to Hawaii, covering an area more than 5 times the land area of the islands. Some of the individual debris avalanches are more than 200 km long and about 5000 km3 in volume, ranking them among the largest on Earth. The slope failures that produce these deposits begin early in the history of individual volcanoes when they are small submarine seamounts, culminate near the end of subaerial shield building, and apparently continue long after dormancy. Consequently, landslide debris is an important element in the internal structure of the volcanoes. The dynamic behavior of the volcanoes can be modulated by slope failure, and the structural features of the landslides are related to elements of the volcanoes including rift zones and fault systems. The landslides are of two general types, slumps and debris avalanches. The slumps are slow moving, wide (up to 110 km), and thick (about 10 km) with transverse blocky ridges and steep toes. The debris avalanches are fast moving, long (up to 230 km) compared to width, and thinner (0.05-2 km); they commonly have a well-defined amphitheater at their head and hummocky terrain in the lower part. Oceanic disturbance caused by rapid emplacement of debris avalanches may have produced high-level wave deposits (such as the 365-m elevation Hulopoe Gravel on Lanai) that are found on several islands. Most present-day submarine canyons were originally carved subaerially in the upper parts of debris avalanches. Subaerial canyon cutting was apparently promoted by the recently steepened and stripped slopes of the landslide amphitheaters.

  18. The 1929 Grand Banks submarine landslide revisited

    NASA Astrophysics Data System (ADS)

    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.

  19. Hydrogen isotope systematics of submarine basalts

    USGS Publications Warehouse

    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.

  20. Miniature Robotic Submarine for Exploring Harsh Environments

    NASA Technical Reports Server (NTRS)

    Behar, Alberto; Bruhn, Fredrik; Carsey, Frank

    2004-01-01

    The miniature autonomous submersible explorer (MASE) has been proposed as a means of scientific exploration -- especially, looking for signs of life -- in harsh, relatively inaccessible underwater environments. Basically, the MASE would be a small instrumented robotic submarine (see figure) that could launch itself or could be launched from another vehicle. Examples of environments that might be explored by use of the MASE include subglacial lakes, deep-ocean hydrothermal vents, acidic or alkaline lakes, brine lenses in permafrost, and ocean regions under Antarctic ice shelves.

  1. Submarine Combat Systems Engineering Project Capstone Project

    DTIC Science & Technology

    2011-06-06

    Surface Warfare Center Carderock Division and Naval Undersea Warfare Center Division Newport. Reproduction of all or part of this report is authorized...criticality of that contact. For example, a distant fishing submarine is not as critical as a nearby warship. As the contact approaches ownship, the...406,159 $507,699 $609,239 $710,779 $2,538,496 2016 1.1253 $104,383 $208,766 $313,149 $417,532 $521,915 $626,298 $730,681 $2,609,574 2017 1.1568

  2. Submarine harbor navigation using image data

    NASA Astrophysics Data System (ADS)

    Stubberud, Stephen C.; Kramer, Kathleen A.

    2017-01-01

    The process of ingress and egress of a United States Navy submarine is a human-intensive process that takes numerous individuals to monitor locations and for hazards. Sailors pass vocal information to bridge where it is processed manually. There is interest in using video imaging of the periscope view to more automatically provide navigation within harbors and other points of ingress and egress. In this paper, video-based navigation is examined as a target-tracking problem. While some image-processing methods claim to provide range information, the moving platform problem and weather concerns, such as fog, reduce the effectiveness of these range estimates. The video-navigation problem then becomes an angle-only tracking problem. Angle-only tracking is known to be fraught with difficulties, due to the fact that the unobservable space is not the null space. When using a Kalman filter estimator to perform the tracking, significant errors arise which could endanger the submarine. This work analyzes the performance of the Kalman filter when angle-only measurements are used to provide the target tracks. This paper addresses estimation unobservability and the minimal set of requirements that are needed to address it in this complex but real-world problem. Three major issues are addressed: the knowledge of navigation beacons/landmarks' locations, the minimal number of these beacons needed to maintain the course, and update rates of the angles of the landmarks as the periscope rotates and landmarks become obscured due to blockage and weather. The goal is to address the problem of navigation to and from the docks, while maintaining the traversing of the harbor channel based on maritime rules relying solely on the image-based data. The minimal number of beacons will be considered. For this effort, the image correlation from frame to frame is assumed to be achieved perfectly. Variation in the update rates and the dropping of data due to rotation and obscuration is considered

  3. Comparative Naval Architecture of Modern Foreign Submarines

    DTIC Science & Technology

    1988-05-01

    3 (e) 3 (e) VOLUME OF LARGEST 20000 (e) 26500 45930 18450 24720 WT SPACE, cuft MBT VOLUME, cuft 24500 12250 9975 11340 8400 MBT/ COMPT RATIO: 1.225...OF LARGEST 28923 26446 19300 19971 3370 WT SPACE, cuft MBT VOLUME, cuft 7350 9310 6300 2450 420 MBT/ COMPT RATIO: 0.254 o.352 0.326 0. 122 0. 124 Table...down, enabling the submarine to aviod sinking. The "MBT/ COMPT " ratio Is the fraction of the largest compartment volume which could be flooded before 90

  4. The IODP 'Nankai Trough Submarine Landslide History

    NASA Astrophysics Data System (ADS)

    Strasser, Michael; Moore, Gregory F.

    2010-05-01

    With increasing awareness of oceanic geohazards, submarine landslides are gaining wide attention not only because of their catastrophic impacts (e.g. landslide-induced tsunamis), but also because they can be directly related to primary trigger mechanisms including earthquakes, rapid sedimentation, gas release, or clathrate dissociation, many of which represent geohazards themselves. Ocean drilling is a key element in understanding such geohazards, given that the submarine geological record preserves structures and past occurrences. To improve our knowledge, quantitative constraints on frequency and magnitude on relevant timescales need to be related to trigger and failure mechanisms. Towards this goal, the Ancillary Project Letter "Nankai Trough Submarine Landslide History" (NanTroSLIDE) aims to add one site to the IODP Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) study area to constrain timing, causes and consequences of submarine landslides in this well-studied accretionary complex. 3D seismic data interpretation in this area offshore Kii Peninsula, SW Japan, reveals a peculiar slope basin sedimentary succession that is composed of stacked Pleistocene-to-recent mass-transport deposits (MTDs), as seismically imaged by acoustically transparent to chaotic bodies with ponded geometries. A nearby small slope basin has been drilled during IODP NanTroSEIZE Stage 1a expedition 316. Site C0008 is located seaward of a prominent out-of-sequence thrust (OOST - mega splay fault). In the lower part of the slope-basin stratigraphic succession, early Pleistocene MTDs document increased slope failure activity along the upthrusted hangingwall block during a period of increased OOST activity. Apart from the deepest section, Site C0008 lacks clear evidence for MTDs, mainly because of a significant hiatus in its upper part, resulting from recent slumping. Proposed Drilling in a lower slope basin that (i) better represents the depocenter for downslope mass transport, (ii

  5. Optimism Bias in Fans and Sports Reporters.

    PubMed

    Love, Bradley C; Kopeć, Łukasz; Guest, Olivia

    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).

  6. Optimism Bias in Fans and Sports Reporters

    PubMed Central

    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

  7. The mediating role of facebook fan pages.

    PubMed

    Chih, Wen-Hai; Hsu, Li-Chun; Wang, Kai-Yu; Lin, Kuan-Yu

    2014-01-01

    Using the dual mediation hypothesis, this study investigates the role of interestingness (the power of attracting or holding one's attention) attitude towards the news, in the formation of Facebook Fan Page users' electronic word-of-mouth intentions. A total of 599 Facebook fan page users in Taiwan were recruited and structural equation modeling (SEM) was used to test the research hypotheses. The results show that both perceived news entertainment and informativeness positively influence interestingness attitude towards the news. Interestingness attitude towards the news subsequently influences hedonism and utilitarianism attitudes towards the Fan Page, which then influence eWOM intentions. Interestingness attitude towards the news plays a more important role than hedonism and utilitarianism attitudes in generating electronic word-of-mouth intentions. Based on the findings, the implications and future research suggestions are provided.

  8. Transformation-optical Fan-beam Synthesis

    NASA Astrophysics Data System (ADS)

    Yang, Rui; Kong, Xianghui; Wang, Hui; Su, He; Lei, Zhenya; Wang, Jing; Zhang, Aofang; Chen, Lei

    2016-02-01

    Gradient-index dielectric lenses are generated based on the coordinate transformation by compressing the homogeneous air spaces quasi-conformally towards and outwards the primary source. The three-dimensional modeling is then performed through revolving the prescribed transformational media 180 degrees around the focal point to reach the architecture of barrel-vaults. It is found that all these two- and three-dimensional transformation-optical designs are capable of producing fan-beams efficiently over a broad frequency range with their main lobes possessing the narrow beamwidth in one dimension and the wide beamwidth in the other, while having the great ability of the wide angular scanning. Finally, we propose to construct such four types of fan-beam lenses through multiple-layered dielectrics with non-uniformed perforations and experimentally demonstrate their excellent performances in the fan-beam synthesis.

  9. Noise Measurements of the VAIIPR Fan

    NASA Technical Reports Server (NTRS)

    Mendoza, Jeff; Weir, Don

    2012-01-01

    This final report has been prepared by Honeywell Aerospace, Phoenix, Arizona, a unit of Honeywell International, Inc., documenting work performed during the period September 2004 through November 2005 for the National Aeronautics and Space Administration (NASA) Glenn Research Center, Cleveland, Ohio, under the Revolutionary Aero-Space Engine Research (RASER) Program, Contract No. NAS3- 01136, Task Order 6, Noise Measurements of the VAIIPR Fan. The NASA Task Manager was Dr. Joe Grady, NASA Glenn Research Center, Mail Code 60-6, Cleveland, Ohio 44135. The NASA Contract Officer was Mr. Albert Spence, NASA Glenn Research Center, Mail Code 60-6, Cleveland, Ohio 44135. This report focuses on the evaluation of internal fan noise as generated from various inflow disturbances based on measurements made from a circumferential array of sensors located near the fan and sensors upstream of a serpentine inlet.

  10. Transformation-optical Fan-beam Synthesis

    PubMed Central

    Yang, Rui; Kong, Xianghui; Wang, Hui; Su, He; Lei, Zhenya; Wang, Jing; Zhang, Aofang; Chen, Lei

    2016-01-01

    Gradient-index dielectric lenses are generated based on the coordinate transformation by compressing the homogeneous air spaces quasi-conformally towards and outwards the primary source. The three-dimensional modeling is then performed through revolving the prescribed transformational media 180 degrees around the focal point to reach the architecture of barrel-vaults. It is found that all these two- and three-dimensional transformation-optical designs are capable of producing fan-beams efficiently over a broad frequency range with their main lobes possessing the narrow beamwidth in one dimension and the wide beamwidth in the other, while having the great ability of the wide angular scanning. Finally, we propose to construct such four types of fan-beam lenses through multiple-layered dielectrics with non-uniformed perforations and experimentally demonstrate their excellent performances in the fan-beam synthesis. PMID:26847048

  11. Fan Noise Source Diagnostic Test: Rotor Alone Aerodynamic Performance Results

    NASA Technical Reports Server (NTRS)

    Hughes, Christopher E.; Jeracki, Robert J.; Woodward, Richard P.; Miller, Christopher J.

    2005-01-01

    The aerodynamic performance of an isolated fan or rotor alone model was measured in the NASA Glenn Research Center 9- by 15- Foot Low Speed Wind Tunnel as part of the Fan Broadband Source Diagnostic Test conducted at NASA Glenn. The Source Diagnostic Test was conducted to identify the noise sources within a wind tunnel scale model of a turbofan engine and quantify their contribution to the overall system noise level. The fan was part of a 1/5th scale model representation of the bypass stage of a current technology turbofan engine. For the rotor alone testing, the fan and nacelle, including the inlet, external cowl, and fixed area fan exit nozzle, were modeled in the test hardware; the internal outlet guide vanes located behind the fan were removed. Without the outlet guide vanes, the velocity at the nozzle exit changes significantly, thereby affecting the fan performance. As part of the investigation, variations in the fan nozzle area were tested in order to match as closely as possible the rotor alone performance with the fan performance obtained with the outlet guide vanes installed. The fan operating performance was determined using fixed pressure/temperature combination rakes and the corrected weight flow. The performance results indicate that a suitable nozzle exit was achieved to be able to closely match the rotor alone and fan/outlet guide vane configuration performance on the sea level operating line. A small shift in the slope of the sea level operating line was measured, which resulted in a slightly higher rotor alone fan pressure ratio at take-off conditions, matched fan performance at cutback conditions, and a slightly lower rotor alone fan pressure ratio at approach conditions. However, the small differences in fan performance at all fan conditions were considered too small to affect the fan acoustic performance.

  12. Directional scales of heterogeneity in alluvial fan aquifers

    SciTech Connect

    Neton, M.J.; Dorsch, J.; Young, S.C.; Olson, C.D. . Dept. of Geological Sciences Tennessee Valley Authority Engineering Lab., Norris, TN )

    1992-01-01

    Abrupt lateral and vertical permeability changes of up to 12 orders of magnitude are common in alluvial fan aquifers due to depositional heterogeneity. This abrupt heterogeneity is problematic, particularly in construction of a continuous hydraulic conductivity field from point measurements. Site characterization is improved through use of a scale-and-directionally-related model of fan heterogeneities. A directional classification of alluvial fan aquifer heterogeneities is proposed. The three directional scales of heterogeneity in alluvial fan aquifers are: (1) within-fan, (2) between-fan (strike-parallel), and (3) cross-fan (strike-perpendicular). Within-fan heterogeneity ranges from very small-scale intergrain relationships which control the nature of pores, to larger scale permeability trends between fan apex and toe, and includes abrupt lateral and vertical facies relationships. Between-fan heterogeneities are of a larger-scale and include differences between adjacent (non)coalescent fans along a basin-margin fault due primarily to changes in lithology between adjacent upland source basins. These differences produce different (a) grain and pore fluid compositions, (b) lithologic facies and proportions, and (c) down-fan fining trends, between adjacent fans. Cross-fan heterogeneities extend from source to basin. Fan deposits are in abrupt contact upgradient with low permeability, basin-margin source rock. Downgradient, fan deposits are in gradational to abrupt contact with time-equivalent, generally lower permeability deposits of lake, desert, longitudinal braided and meandering river, volcanic, and shallow marine environments. Throughout basin history these environments may abruptly cover the fan with low permeability horizons.

  13. How are giant clasts incorporated into submarine landslides and how do they change flow dynamics?

    NASA Astrophysics Data System (ADS)

    Ortiz-Karpf, A.; Hodgson, D.; Jackson, C. A. L.; Spychala, Y.; Hannah, B. L.; McCaffrey, W. D.

    2015-12-01

    Giant clasts (>10,000 m3) are common in many submarine landslide deposits. Here, we use submarine landslide deposits exposed in the field (Karoo Basin, South Africa and Neuquén Basin, Argentina) and imaged in high-resolution reflection seismic data (offshore Colombia and offshore Brazil) to investigate how giant clasts were entrained and transported in the parent flows, and how they changed longitudinal flow behaviour. Based on: (i) facies/seismic facies similarities between clast and substrate; (ii) evidence for basal scour at a scale comparable to the clasts; and (iii) the spatial association of scours and clasts, we are able to discriminate between clasts derived from the substrate during flow run-out rather than from headwall degradation. Highly sheared basal surfaces are well-developed in distal locations, sometimes extending beyond the deposit. This points to deformation and weakening of the substrate ahead of the flow, thus providing a potential mechanism to entrain large clasts on low gradients in the absence of basal flow turbulence. Scours and ramps on the basal shear surface, which are associated with concentrations of large clasts, commonly occur where bathymetric changes are abrupt (confinement and/or steepening) or where more easily eroded substrate are encountered (e.g. sand-prone channel-fills). Substrate entrainment bulks the flow volume along during flow evolution, thereby increasing mass and momentum. Our outcrop and subsurface examples point to a complicated interplay between flow evolution, bathymetry, and substrate geology, which combine to control the development of the basal shear surface. Improved understanding of these interrelationships will help to refine the estimates of the volumes and runout distances, and therefore geohazard potential, of submarine landslides.

  14. Formation of submarine flat-topped volcanic cones in Hawai'i

    NASA Astrophysics Data System (ADS)

    Clague, David A.; Moore, James G.; Reynolds, Jennifer R.

    simultaneously build the rim outward and upward, but also dam and fill in the low point on the rim. The process repeats at the new lowest point, forming a circular structure with a flat horizontal top and steep pillowed margins. There is a delicate balance between lava (heat) supply to the pond and cooling and thickening of the floating crust. Factors that facilitate construction of such landforms include effusive eruption of lava with low volatile contents, moderate to high confining pressure at moderate to great ocean depth, long-lived steady eruption (years to decades), moderate effusion rates (probably ca. 0.1km3/year), and low, but not necessarily flat, slopes. With higher effusion rates, sheet flows flood the slope. With lower effusion rates, pillow mounds form. Hawaiian shield-stage eruptions begin as fissure eruptions. If the eruption is too brief, it will not consolidate activity at a point, and fissure-fed flows will form a pond with irregular levees. The pond will solidify between eruptive pulses if the eruption is not steady. Lava that is too volatile rich or that is erupted in too shallow water will produce fragmental and highly vesicular lava that will accumulate to form steep pointed cones, as occurs during the post-shield stage. The steady effusion of lava on land constructs lava shields, which are probably the subaerial analogs to submarine flat-topped cones but formed under different cooling conditions.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Sediment sound velocities from sonobuoys: Arabian fan

    SciTech Connect

    Bachman, R.T.; Hamilton, E.L.

    1980-02-10

    Eight variable-angle seismic reflection stations in the Arabian Fan, Northwestern Indian Ocean, provided 40 determinations of sound velocity in sediment and sedimentary rock. Sound velocity in the homogeneous, largely terrigenous fan increases smoothly with depth. Regression analysis yielded the velocity-time relationship V (km/s)=1.510+1.863t, where V is instantaneous velocity and t is one-way travel time below the sea floor to 1 s. The velocity-depth function is V (km/s)=1.510+1.200h-0.253h/sup 2/+ 0.034h/sup 3/, where h is subbottom depth in km.

  17. Fan-less long range alpha detector

    DOEpatents

    MacArthur, D.W.; Bounds, J.A.

    1994-05-10

    A fan-less long range alpha detector is disclosed which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces. 2 figures.

  18. Theoretical Determination of Axial Fan Performance

    NASA Technical Reports Server (NTRS)

    Struve, E.

    1943-01-01

    The report presents a method for the computation of axial fan characteristics. The method is based on the assumption that the law of constancy of the circulation along the blade holds, approximately, for all fan conditions for which the blade elements operate at normal angles of attack (up to the stalling angles). Pressure head coefficient K(sub a) and power coefficient K(sub u) for the force components in the axial and tangential directions, respectively, and analogous to the lift and drag coefficients C(sub y) and C(sub x) are conveniently introduced.

  19. Sport fans' impressions of gay male athletes.

    PubMed

    Campbell, Jamonn; Cothren, Denise; Rogers, Ross; Kistler, Lindsay; Osowski, Anne; Greenauer, Nathan; End, Christian

    2011-01-01

    The purpose of this study was to examine sport fans' impressions of gay male athletes. Participants formed impressions of a fictional athlete from their favorite team after reading a short scenario about the player. The scenarios described the athlete as being gay or straight, and either becoming a distraction or not causing a distraction to the team. While males' ratings of the athlete did not significantly differ, female fans formed significantly more positive impressions of the gay male player than the straight athlete. These results are discussed in terms of the ingroup bias and the shifting culture of homophobia in sport.

  20. Fan-less long range alpha detector

    DOEpatents

    MacArthur, Duncan W.; Bounds, John A.

    1994-01-01

    A fan-less long range alpha detector which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces.

  1. Numerical simulation for fan broadband noise prediction

    NASA Astrophysics Data System (ADS)

    Hase, Takaaki; Yamasaki, Nobuhiko; Ooishi, Tsutomu

    2011-03-01

    In order to elucidate the broadband noise of fan, the numerical simulation of fan operating at two different rotational speeds is carried out using the three-dimensional unsteady Reynolds-averaged Navier-Stokes (URANS) equations. The computed results are compared to experiment to estimate its accuracy and are found to show good agreement with experiment. A method is proposed to evaluate the turbulent kinetic energy in the framework of the Spalart-Allmaras one equation turbulence model. From the calculation results, the turbulent kinetic energy is visualized as the turbulence of the flow which leads to generate the broadband noise, and its noise sources are identified.

  2. OSCEE fan exhaust bulk absorber treatment evaluation

    NASA Technical Reports Server (NTRS)

    Bloomer, H. E.; Samanich, N. E.

    1980-01-01

    The acoustic suppression capability of bulk absorber material designed for use in the fan exhaust duct walls of the quiet clean short haul experiment engine (OCSEE UTW) was evaluated. The acoustic suppression to the original design for the engine fan duct which consisted of phased single degree-of-freedom wall treatment was tested with a splitter and also with the splitter removed. Peak suppression was about as predicted with the bulk absorber configuration, however, the broadband characteristics were not attained. Post test inspection revealed surface oil contamination on the bulk material which could have caused the loss in bandwidth suppression.

  3. Fan and Open-Rotor Noise

    NASA Technical Reports Server (NTRS)

    Miller, Christopher J.

    2010-01-01

    This presentation is a technical progress report and near term outlook for work on fan (in-duct) and open-rotor (high speed propeller) noise funded by NASA's Fundamental Aeronautics Program, Subsonic Fixed Wing (SFW) Project and the Integrated Systems Research Program, Environmentally Responsible Aircraft Project. Sections of the presentation cover: the system level metrics are outlined for the SFW timeframes (2015, 2020 1 2025); the Ultra-High Bypass ratio technology development roadmap; a feasibility study for a low technology readiness level fan test rig; the development plan for a turbomachinery oriented computational aero-acoustics code; and systems analysis work on open-rotor modeling.

  4. Development and Evaluation of a Hyperbaric Toxic Gas Monitor (SubTox) for Disabled Submarines

    DTIC Science & Technology

    2013-08-01

    DEVELOPMENT AND EVALUATION OF A HYPERBARIC TOXIC GAS MONITOR (SUBTOX) FOR DISABLED SUBMARINES...HYPERBARIC TOXIC GAS MONITOR (SUBTOX) FOR DISABLED SUBMARINES 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) R. S. Lillo...for monitoring toxic gases on disabled submarines (DISSUBs) rely on chemical detector tubes to determine when submarine escape action levels (SEALs

  5. Plasma confinement at JET

    NASA Astrophysics Data System (ADS)

    Nunes, I.; JET Contributors

    2016-01-01

    Operation with a Be/W wall at JET (JET-ILW) has an impact on scenario development and energy confinement with respect to the carbon wall (JET-C). The main differences observed were (1) strong accumulation of W in the plasma core and (2) the need to mitigate the divertor target temperature to avoid W sputtering by Be and other low Z impurities and (3) a decrease of plasma energy confinement. A major difference is observed on the pedestal pressure, namely a reduction of the pedestal temperature which, due to profile stiffness the plasma core temperature is also reduced leading to a degradation of the global confinement. This effect is more pronounced in low β N scenarios. At high β N, the impact of the wall on the plasma energy confinement is mitigated by the weaker plasma energy degradation with power relative to the IPB98(y, 2) scaling calculated empirically for a CFC first wall. The smaller tolerable impurity concentration for tungsten (<10-5) compared to that of carbon requires the use of electron heating methods to prevent W accumulation in the plasma core region as well as gas puffing to avoid W entering the plasma core by ELM flushing and reduction of the W source by decreasing the target temperature. W source and the target temperature can also be controlled by impurity seeding. Nitrogen and Neon have been used and with both gases the reduction of the W source and the target temperature is observed. Whilst more experiments with Neon are necessary to assess its impact on energy confinement, a partial increase of plasma energy confinement is observed with Nitrogen, through the increase of edge temperature. The challenge for scenario development at JET is to extend the pulse length curtailed by its transient behavior (W accumulation or MHD), but more importantly by the divertor target temperature limits. Re-optimisation of the scenarios to mitigate the effect of the change of wall materials maintaining high global energy confinement similar to JET-C is

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Structural integrity of wind tunnel wooden fan blades

    NASA Technical Reports Server (NTRS)

    Young, Clarence P., Jr.; Wingate, Robert T.; Rooker, James R.; Mort, Kenneth W.; Zager, Harold E.

    1991-01-01

    Information is presented which was compiled by the NASA Inter-Center Committee on Structural Integrity of Wooden Fan Blades and is intended for use as a guide in design, fabrication, evaluation, and assurance of fan systems using wooden blades. A risk assessment approach for existing NASA wind tunnels with wooden fan blades is provided. Also, state of the art information is provided for wooden fan blade design, drive system considerations, inspection and monitoring methods, and fan blade repair. Proposed research and development activities are discussed, and recommendations are provided which are aimed at future wooden fan blade design activities and safely maintaining existing NASA wind tunnel fan blades. Information is presented that will be of value to wooden fan blade designers, fabricators, inspectors, and wind tunnel operations personnel.

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

    NASA Technical Reports Server (NTRS)

    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.

  9. Improving Fan System Performance: A Sourcebook for Industry

    SciTech Connect

    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.

  10. 5. AEROVANE FAN HOOD FROM NORTHWEST. MANWAY SHAFT DOORS AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. AEROVANE FAN HOOD FROM NORTHWEST. MANWAY SHAFT DOORS AND METAL FRAGMENT AT RIGHT REAR. - Consolidation Coal Company Mine No. 11, Aerovane Fan, East side of State Route 936, Midlothian, Allegany County, MD

  11. 1. A BRICK AND CONCRETE FAN HOUSING ADJACENT TO ONE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. A BRICK AND CONCRETE FAN HOUSING ADJACENT TO ONE OF THE ADIT OPENINGS (VIEW TO THE NORTH). - Foster Gulch Mine, Fan Housing, Bear Creek 1 mile Southwest of Town of Bear Creek, Red Lodge, Carbon County, MT

  12. The Shape of Trail Canyon Alluvial Fan, Death Valley

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Dohrenwend, John C.

    1993-01-01

    A modified conic equation has been fit to high-resolution digital topographic data for Trail Canyon alluvial fan in Death Valley, California. Fits were accomplished for 3 individual fan units of different age.

  13. Fan blade development. Final report Sep 81-Sep 82

    SciTech Connect

    Buday, J.M.

    1982-09-01

    The objective of this program was to develop an improved fan blade that could be utilized in place of the current steel fan blade on the Pedal Ventilator Kit (PVK). The goals of the program were to reduce both the unit cost and weight of the fan while maintaining its effectiveness and reliability. A value analysis study was conducted on the fan blade to determine material/design revisions that offered potential manufacturing economies. Based on the conclusions of the study, two designs were chosen for fabrication. The two fan designs were constructed and tested. As a result of the performance testing, one fan blade emerged as the optimum design. Fifteen fan blades of the optimum design were constructed for FEMA inspection and distribution. Preliminary specifications were generated for the fan blade assembly. in addition, production cost estimates based on a procurement of 100,000 units were formulated for FEMA budgetary purposes.

  14. Simulation of detonation of ammonium nitrate fuel oil mixture confined by aluminum: edge angles for DSD

    SciTech Connect

    Short, Mark; Quirk, James J; Kiyanda, Charles B; Jackson, Scott I; Briggs, Matthew E; Shinas, Micheal A

    2010-01-01

    Non-ideal high explosives are typically porous, low-density materials with a low detonation velocity (3--5 km/s) and long detonation reaction zone ({approx} cms). As a result, the interaction of a non-ideal high explosive with an inert confiner can be markedly different than for a conventional high explosive. Issues arise, for example, with light stiff confiners where the confiner can drive the high explosive (HE) through a Prandtl-Meyer fan at the HE/confiner interface rather than the HE driving the confiner. For a non-ideal high explosive confined by a high sound speed inert such that the detonation velocity is lower than the inert sound speed, the flow is subsonic and thus shockless in the confiner. In such cases, the standard detonation shock dynamics methodology, which requires a positive edge-angle be specified at the HE/confiner interface in order that the detonation shape be divergent, cannot be directly utilized. In order to study how detonation shock dynamics can be utilized in such cases, numerical simulations of the detonation of ammonium nitrate-fuel oil (ANFO) confined by aluminum 6061 are conducted.

  15. Submarine 'safe to escape' studies in man.

    PubMed

    Jurd, K M; Seddon, F M; Thacker, J C; Blogg, S L; Stansfield, M R D; White, M G; Loveman, G A M

    2014-01-01

    The Royal Navy requires reliable advice on the safe limits of escape from a distressed submarine (DISSUB). Flooding in a DISSUB may cause a rise in ambient pressure, increasing the risk of decompression sickness (DCS) and decreasing the maximum depth from which it is safe to escape. The aim of this study was to investigate the pressure/depth limits to escape following saturation at raised ambient pressure. Exposure to saturation pressures up to 1.6 bar (a) (160 kPa) (n = 38); escapes from depths down to 120 meters of sea water (msw) (n = 254) and a combination of saturation followed by escape (n = 90) was carried out in the QinetiQ Submarine Escape Simulator, Alverstoke, United Kingdom. Doppler ultrasound monitoring was used to judge the severity of decompression stress. The trials confirmed the previously untested advice, in the Guardbook, that if a DISSUB was lying at a depth of 90 msw, then it was safe to escape when the pressure in the DISSUB was 1.5 bar (a), but also indicated that this advice may be overly conservative. This study demonstrated that the upper DISSUB saturation pressure limit to safe escape from 90 msw was 1.6 bar (a), resulting in two cases of DCS.

  16. Deep-Sea Submarine 'Ben Franklin'

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The deep-sea submarine 'Ben Franklin' is being docked in the harbor. Named for American patriot and inventor Ben Franklin, who discovered the Gulf Steam, the 50-foot Ben Franklin was built between 1966 and 1968 in Switzerland for deep-ocean explorer Jacques Piccard and the Grumman Aircraft Engineering Corporation. The submersible made a famous 30-day drift dive off the East Coast of the United States and Canada in 1969 mapping the Gulf Stream's currents and sea life. It also made space exploration history by studying the behavior of aquanauts in a sealed, self-contained, self-sufficient capsule for NASA. On July 14, 1969, the Ben Franklin was towed to the high-velocity center of the Stream off the coast of Palm Beach, Florida. With a NASA observer on board, the sub descended to 1,000 feet off of Riviera Beach, Florida and drifted 1,400 miles north with the current for more than four weeks, reemerging near Maine. During the course of the dive, NASA conducted exhaustive analyses of virtually every aspect of onboard life. They measured sleep quality and patterns, sense of humor and behavioral shifts, physical reflexes, and the effect of a long-term routine on the crew. The submarine's record-shattering dive influenced the design of Apollo and Skylab missions and continued to guide NASA scientists as they devised future marned space-flight missions.

  17. Deep-Sea Research Submarine 'Ben Franklin'

    NASA Technical Reports Server (NTRS)

    1969-01-01

    This is an aerial view of the deep-sea research submarine 'Ben Franklin' at dock. Named for American patriot and inventor Ben Franklin, who discovered the Gulf Steam, the 50-foot Ben Franklin was built between 1966 and 1968 in Switzerland for deep-ocean explorer Jacques Piccard and the Grumman Aircraft Engineering Corporation. The submersible made a famous 30-day drift dive off the East Coast of the United States and Canada in 1969 mapping the Gulf Stream's currents and sea life, and also made space exploration history by studying the behavior of aquanauts in a sealed, self-contained, self-sufficient capsule for NASA. On July 14, 1969, the Ben Franklin was towed to the high-velocity center of the Stream off the coast of Palm Beach, Florida. With a NASA observer on board, the sub descended to 1,000 feet off of Riviera Beach, Florida and drifted 1,400 miles north with the current for more than four weeks, reemerging near Maine. During the course of the dive, NASA conducted exhaustive analyses of virtually every aspect of onboard life. They measured sleep quality and patterns, sense of humor and behavioral shifts, physical reflexes, and the effects of a long-term routine on the crew. The submarine's record-shattering dive influenced the design of Apollo and Skylab missions and continued to guide NASA scientists as they devised future marned space-flight missions.

  18. Deep-Sea Submarine 'Ben Franklin'

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The deep-sea submarine 'Ben Franklin' is being docked in the harbor. Named for American patriot and inventor Ben Franklin, who discovered the Gulf Steam, the 50-foot Ben Franklin was built between 1966 and 1968 in Switzerland for deep-ocean explorer Jacques Piccard and the Grumman Aircraft Engineering Corporation. The submersible made a famous 30-day drift dive off the East Coast of the United States and Canada in 1969 mapping the Gulf Stream's currents and sea life. It also made space exploration history by studying the behavior of aquanauts in a sealed, self-contained, self-sufficient capsule for NASA. On July 14, 1969, the Ben Franklin was towed to the high-velocity center of the Stream off the coast of Palm Beach, Florida. With a NASA observer on board, the sub descended to 1,000 feet off of Riviera Beach, Florida and drifted 1,400 miles north with the current for more than four weeks, reemerging near Maine. During the course of the dive, NASA conducted exhaustive analyses of virtually every aspect of onboard life. They measured sleep quality and patterns, sense of humor and behavioral shifts, physical reflexes, and the effect of a long-term routine on the crew. The submarine's record-shattering dive influenced the design of Apollo and Skylab missions and continued to guide NASA scientists as they devised future marned space-flight missions.

  19. Flow dynamics around downwelling submarine canyons

    NASA Astrophysics Data System (ADS)

    Spurgin, J. M.; Allen, S. E.

    2014-10-01

    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.

  20. Flow dynamics around downwelling submarine canyons

    NASA Astrophysics Data System (ADS)

    Spurgin, J. M.; Allen, S. E.

    2014-05-01

    Flow dynamics around a downwelling submarine canyon were analysed with the Massachusetts Institute of Technology general circulation model. Blanes Canyon (Northwest Mediterranean) was used for topographic and initial forcing conditions. Fourteen scenarios were modelled with varying forcing conditions. Rossby number and Burger number 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. 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 were explained within this new dynamic framework.

  1. Mineralized microbes from Giggenbach submarine volcano

    NASA Astrophysics Data System (ADS)

    Jones, Brian; de Ronde, C. E. J.; Renaut, Robin W.

    2008-08-01

    The Giggenbach submarine volcano, which forms part of the Kermadec active arc front, is located ˜780 km NNE of the North Island of New Zealand. Samples collected from chimneys associated with seafloor hydrothermal vents on this volcano, at a depth of 160-180 m, contain silicified microbes and microbes entombed in reticular Fe-rich precipitates. The mineralized biota includes filamentous, rod-shaped, and rare coccoid microbes. In the absence of organic carbon for rDNA analysis or preserved cells, the taxonomic affinity of these microbes, in terms of extant taxa, remains questionable because of their architectural simplicity and the paucity of taxonomically significant features. The three-dimensional preservation of the microbes indicates rapid mineralization with a steady supply of supersaturated fluids to the nucleation sites present on the surfaces of the microbes. The mineralization styles evident in the microbes from the Giggenbach submarine volcano are similar to those associated with mineralized microbes found in terrestrial hot spring deposits in New Zealand, Iceland, Yellowstone, and Kenya. These similarities exist even though the microbes are probably different and the fluids become supersaturated with respect to opal-A by different mechanisms. For ancient rocks it means that interpretations of the depositional settings cannot be based solely on the silicified microbes or their style of silicification.

  2. Active Control of Fan Noise in Ducts Using Magnetic Bearings

    DTIC Science & Technology

    2007-11-02

    of magnetic bearings. An axial flow fan creates tonal noise related to its rotational rate. Additional noise exists due to harmonics of this frequency...magnetic bearings. An axial flow fan creates tonal noise related to its rotational rate. Additional noise exists due to harmonics of this frequency as well...systems typically have fans that will move air from the heating or cooling system to any desired space. Fan noise is characterized first by tonal

  3. Supersonic throughflow fans for high-speed aircraft

    NASA Technical Reports Server (NTRS)

    Ball, Calvin L.; Moore, Royce D.

    1990-01-01

    A brief overview is provided of past supersonic throughflow fan activities; technology needs are discussed; the design is described of a supersonic throughflow fan stage, a facility inlet, and a downstream diffuser; and the results are presented from the analysis codes used in executing the design. Also presented is a unique engine concept intended to permit establishing supersonic throughflow within the fan on the runway and maintaining the supersonic throughflow condition within the fan throughout the flight envelope.

  4. An analysis of prop-fan/airframe aerodynamic integration

    NASA Technical Reports Server (NTRS)

    Boctor, M. L.; Clay, C. W.; Watson, C. F.

    1978-01-01

    An approach to aerodynamic integration of turboprops and airframes, with emphasis placed upon wing mounted installations is addressed. Potential flow analytical techniques were employed to study aerodynamic integration of the prop fan propulsion concept with advanced, subsonic, commercial transport airframes. Three basic configurations were defined and analyzed: wing mounted prop fan at a cruise Mach number of 0.8, wing mounted prop fan in a low speed configuration, and aft mounted prop fan at a cruise Mach number of 0.8.

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

    NASA Astrophysics Data System (ADS)

    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

  6. Interfingering sand-rich aprons and Var Fan lobe deposits off Corsica: Analog for thick and laterally extensive turbidite petroleum reservoirs

    SciTech Connect

    Nelson, C.H.; Escutia, C. ); Savoye, B. ); Rehault, J.P. )

    1996-01-01

    The sand-rich Var submarine fan initiates off Nice, France, extends 230 km to the southeast, and then deposits a distal lobe (80 x 40 km) that parallels the northwestern base of the Corsican continental slope. Interfingering with the lobe deposits are base-of-slope, sand-rich aprons derived from Corsica. Both the fan lobe and aprons onlap the outcropping steep (6-110) slopes of Corsica. The fan lobe is characterized by generally flat-bedded layers with the total percentage of sand beds in cores ranging from 60-94% of the Holocene deposits. The aprons are characterized by feeder canyons exhibiting common sediment failures and proximal regions with numerous chaotic layers. With increasing distance from the apron apexes, high amplitude wedging reflectors grade laterally to flatter ones, reflector continuity increases, chaotic layers thin, and some incipient channels form. Chaotic layers are the dominant deposit shown on seismic profiles of the aprons. The layers extend as much as 15 km laterally onto the fan lobe and maximum thicknesses of single layers reach 35-70 m, The prolonged echo character with poor penetration, together with irregular surfaces and possible large blocks seen in sidescan sonar records, suggest that apron deposits are coarse grained. Gravel is found in apron layers that extend 21 km onto the fan lobe and the total percentage of sand beds in cores ranges from 37-79% of the Holocene deposits. Because the estimated sand : shale ratio averages 8.6:1 in the Holocene highstand deposits of the interfingering Corsican aprons and Var Fan lobe, this combined environment is an intriguing setting that could provide large continuous reservoirs if it occurred in a suitable ancient petroleum province.

  7. Interfingering sand-rich aprons and Var Fan lobe deposits off Corsica: Analog for thick and laterally extensive turbidite petroleum reservoirs

    SciTech Connect

    Nelson, C.H.; Escutia, C.; Savoye, B.; Rehault, J.P.

    1996-12-31

    The sand-rich Var submarine fan initiates off Nice, France, extends 230 km to the southeast, and then deposits a distal lobe (80 x 40 km) that parallels the northwestern base of the Corsican continental slope. Interfingering with the lobe deposits are base-of-slope, sand-rich aprons derived from Corsica. Both the fan lobe and aprons onlap the outcropping steep (6-110) slopes of Corsica. The fan lobe is characterized by generally flat-bedded layers with the total percentage of sand beds in cores ranging from 60-94% of the Holocene deposits. The aprons are characterized by feeder canyons exhibiting common sediment failures and proximal regions with numerous chaotic layers. With increasing distance from the apron apexes, high amplitude wedging reflectors grade laterally to flatter ones, reflector continuity increases, chaotic layers thin, and some incipient channels form. Chaotic layers are the dominant deposit shown on seismic profiles of the aprons. The layers extend as much as 15 km laterally onto the fan lobe and maximum thicknesses of single layers reach 35-70 m, The prolonged echo character with poor penetration, together with irregular surfaces and possible large blocks seen in sidescan sonar records, suggest that apron deposits are coarse grained. Gravel is found in apron layers that extend 21 km onto the fan lobe and the total percentage of sand beds in cores ranges from 37-79% of the Holocene deposits. Because the estimated sand : shale ratio averages 8.6:1 in the Holocene highstand deposits of the interfingering Corsican aprons and Var Fan lobe, this combined environment is an intriguing setting that could provide large continuous reservoirs if it occurred in a suitable ancient petroleum province.

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

    ERIC Educational Resources Information Center

    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…

  9. Star Trek Rerun, Reread, Rewritten: Fan Writing as Textual Poaching.

    ERIC Educational Resources Information Center

    Jenkins III, Henry

    1988-01-01

    Discusses women who write fiction and fan literature based on the "Star Trek" universe, outlining how Star Trek fans force the primary text to accommodate alternate interests. Also considers the issue of literary property in light of the moral economy of the fan community that shapes the range of permissible retellings of the program…

  10. 30 CFR 57.8529 - Auxiliary fan systems

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Auxiliary fan systems 57.8529 Section 57.8529 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Underground Only § 57.8529 Auxiliary fan systems When auxiliary fan systems are used, such systems shall...

  11. 30 CFR 75.310 - Installation of main mine fans.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Equipped with a pressure recording device or system. Mines permitted to shut down main mine fans under § 75... June 10, 1997 to install a pressure recording device or system on all main mine fans. If a device or system other than a circular pressure recorder is used to monitor main mine fan pressure, the monitoring...

  12. 30 CFR 75.331 - Auxiliary fans and tubing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... recirculation of air. (b) If a deficiency exists in any auxiliary fan system, the deficiency shall be corrected... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Auxiliary fans and tubing. 75.331 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.331 Auxiliary fans and tubing...

  13. 30 CFR 57.8529 - Auxiliary fan systems

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Auxiliary fan systems 57.8529 Section 57.8529 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Underground Only § 57.8529 Auxiliary fan systems When auxiliary fan systems are used, such systems shall...

  14. 30 CFR 75.331 - Auxiliary fans and tubing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... recirculation of air. (b) If a deficiency exists in any auxiliary fan system, the deficiency shall be corrected... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Auxiliary fans and tubing. 75.331 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.331 Auxiliary fans and tubing...

  15. 10 CFR 429.33 - Ceiling fan light kits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Ceiling fan light kits. 429.33 Section 429.33 Energy... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.33 Ceiling fan light kits. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to ceiling fan light...

  16. 10 CFR 429.33 - Ceiling fan light kits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Ceiling fan light kits. 429.33 Section 429.33 Energy... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.33 Ceiling fan light kits. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to ceiling fan light...

  17. 10 CFR 429.33 - Ceiling fan light kits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Ceiling fan light kits. 429.33 Section 429.33 Energy... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.33 Ceiling fan light kits. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to ceiling fan light...

  18. 16 CFR 305.13 - Labeling for ceiling fans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...: “Compare: 49″ to 60″ ceiling fans have airflow efficiencies ranging from approximately 51 to 176 cubic feet... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Labeling for ceiling fans. 305.13 Section... Disclosures § 305.13 Labeling for ceiling fans. (a) Ceiling fans—(1) Content. Any covered product that is...

  19. 16 CFR 305.13 - Labeling for ceiling fans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...: “Compare: 49″ to 60″ ceiling fans have airflow efficiencies ranging from approximately 51 to 176 cubic feet... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Labeling for ceiling fans. 305.13 Section... Disclosures § 305.13 Labeling for ceiling fans. (a) Ceiling fans—(1) Content. Any covered product that is...

  20. 16 CFR 305.13 - Labeling for ceiling fans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... fans have airflow efficiencies ranging from approximately 71 to 86 cubic feet per minute per watt at... diameter: “Compare: 49″ to 60″ ceiling fans have airflow efficiencies ranging from approximately 51 to 176... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Labeling for ceiling fans. 305.13...