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Sample records for river bend station

  1. 78 FR 50454 - Entergy Operations, Inc., River Bend Station, Unit 1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Entergy Operations, Inc., River Bend Station, Unit 1 AGENCY: Nuclear Regulatory Commission. ACTION...-47, issued to Entergy Operations, Inc. (the licensee), for operation of the River Bend Station, Unit...

  2. 75 FR 61219 - Entergy Operations, Inc.; River Bend Station, Unit 1; Environmental Assessment and Finding of No...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-04

    ... COMMISSION Entergy Operations, Inc.; River Bend Station, Unit 1; Environmental Assessment and Finding of No...-47, issued Entergy Operations, Inc. (Entergy, the licensee), for operation of the River Bend Station, Unit 1 (RBS), located in West Feliciana Parish, Louisiana. In accordance with 10 CFR 51.21, the NRC...

  3. Flood characteristics of the Buffalo River at Tyler Bend, Arkansas

    USGS Publications Warehouse

    Neely, Braxtel L.

    1987-01-01

    The Buffalo River is located in the Ozark Mountains in north-central Arkansas. Tyler Bend is on the Buffalo River about 1.5 miles upstream from U.S. Highway 65. The National Park Service is developing several recreational park sites along this scenic river. The magnitude, frequency, duration and velocities of floods are primary factors needed for establishing guidelines for developing facilities and managing park sites. The Park Service plans to develop park facilities at Tyler Bend and needs flood information at this site. This report provides information on the 100-, 75-, 50-, 30-, 20-, 10-, and 5-year floods on the Buffalo River at Tyler Bend. It was prepared by the U.S. Geological Survey in cooperation with the National Park Service and is based on data collected during the December 1982 flood, gaging station data for the Buffalo River near St. Joe, Arkansas and a Statewide flood-frequency report. (Lantz-PTT)

  4. Advantages of customer/supplier involvement in the upgrade of River Bend`s IST program

    SciTech Connect

    Womack, R.L.; Addison, J.A.

    1996-12-01

    At River Bend Station, IST testing had problems. Operations could not perform the test with the required repeatability; engineering could not reliably trend test data to detect degradation; licensing was heavily burdened with regulatory concerns; and maintenance could not do preventative maintenance because of poor prediction of system health status. Using Energy`s Total Quality principles, it was determined that the causes were: lack of ownership, inadequate test equipment usage, lack of adequate procedures, and lack of program maintenance. After identifying the customers and suppliers of the IST program data, Energy management put together an upgrade team to address these concerns. These customers and suppliers made up the IST upgrade team. The team`s mission was to supply River Bend with a reliable, functional, industry correct and user friendly IST program. The IST program in place went through a verification process that identified and corrected over 400 individual program discrepancies. Over 200 components were identified for improved testing methods. An IST basis document was developed. The operations department was trained on ASME Section XI testing. All IST tests have been simplified and shortened, due to heavy involvement by operations in the procedure development process. This significantly reduced testing time, resulting in lower cost, less dose and greater system availability.

  5. HYDRODYNAMICS AND SEDIMENT TRANSPORT IN LOWER MISSISSIPPI RIVER MEANDER BENDS (LOUISIANA): IMPLICATIONS FOR LARGE SEDIMENT DIVERSIONS

    NASA Astrophysics Data System (ADS)

    Allison, M. A.; McCorquodale, A.; Meselhe, E. A.

    2009-12-01

    Field data collection and numerical modeling is being conducted in the lower Mississippi River in the region of a meander bend at Myrtle Grove, LA (river km 96 above Head of Passes) in support of a proposed large water and sediment diversion (1,130-2,830 cms) for coastal wetland restoration. Field studies in October 2008, April and May 2009, at discharges ranging from 11,000-21,000 cms, examined the role of bend dynamics on sediment transport through this reach relative to control sites further downriver and USGS monitoring stations upriver. Suspended loads and grain size character measured by ADCP (velocities and backscatter), isokinetic point sampler (P-63), and optical sensors (LISST, OBS, transmissometer) indicate that during the rising-to-high discharge phase, sand lifting off from the downstream edge of the lateral bar upriver of the bend augments that carried from further upriver, and is entrained in the upper 10-25m of the water column. This excess suspended sand is advected around the bend before concentrations are reduced to background levels over the lateral bar downstream of the bend. Bedload transport rates measured by repeat swath bathymetric mapping of migrating dunes are comparable upstream of the bend, downstream, and in the control sites. However, no bedforms are observed in the bend thalweg (up to 60 m deep) supporting the dominance of suspended sand transport in the bend. Both 1D (HEC-RAS and HEC6-T) and 3D (Flow3D) numerical hydrodynamic and sediment transport modeling is underway to simulate this process and the large-scale eddy present in the bend that generates upriver transport along the inside of the meander bend at all observed discharges. Our preliminary results suggest that the outside of meander bends might be an appropriate site for sediment diversions that draw near-surface water from this sediment-rich layer.

  6. Sharp bends associated with deep scours in a tropical river: The river Mahakam (East Kalimantan, Indonesia)

    NASA Astrophysics Data System (ADS)

    Vermeulen, B.; Hoitink, A. J. F.; Berkum, S. W.; Hidayat, H.

    2014-07-01

    Autogenic scouring in sharp river bends has received ample attention in laboratory and modeling studies. These studies have significantly advanced our understanding of how flow processes are influenced by strong curvature and how they affect the bathymetry. Here we present a 300 km reach of the Mahakam River in Indonesia, which features several sharp bends (W/R > 0.5), providing a unique field data set to validate existing knowledge on sharp bends. Scour depths were found to strongly exceed what can be expected based on existing understanding of sharp bends and are highly correlated with curvature. A comprehensive stream reconnaissance was carried out to compare the occurrence of sharp bends and deep scours with lateral bank migration. Histograms of the occurrence of erosive, stable, advancing, and bar-type banks as a function of curvature quantify the switch from a mildly curved bend regime to a sharp bend regime. In mild bends, outer banks erode and inner banks advance. In sharp bends the erosion pattern inverts. Outer banks stabilize or advance, while inner banks erode. In sharply curved river bends, bars occur near the outer banks that become less erosive for higher curvatures. Inner banks become more erosive for higher curvatures but nevertheless accommodate the larger portion of exposed bars. No relation was found between the land cover adjacent to the river and the occurrence of sharp bends. Soil processes may play a crucial role in the formation of sharp bends, which is inferred from iron and manganese concretions observed in the riverbanks, indicating ferric horizons and early stages of the formation of plinthic horizons. Historical topographic maps show the planform activity of the river is low, which may relate to the scour holes slowing down planimetric development.

  7. 78 FR 28001 - In the Matter of Entergy Gulf States Louisiana, LLC., and Entergy Operations, Inc., River Bend...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-13

    ... COMMISSION In the Matter of Entergy Gulf States Louisiana, LLC., and Entergy Operations, Inc., River Bend Station, Unit 1; Order Approving Direct and Indirect Transfers of License I Entergy Gulf States Louisiana... Spent Fuel Storage Installation, to a new limited liability company also named Entergy Gulf...

  8. History of the Priest River Experiment Station

    Treesearch

    Kathleen L. Graham

    2004-01-01

    In 1911, the U.S. Forest Service established the Priest River Experimental Forest near Priest River, Idaho. The Forest served as headquarters for the Priest River Forest Experiment Station and continues to be used for forest research critical to understanding forest development and the many processes, structures, and functions occurring in them. At...

  9. Using Timelapse LiDAR to Quantify River Bend Change on the Coastal Trinity River, TX

    NASA Astrophysics Data System (ADS)

    Mason, J.; Mohrig, D. C.

    2016-12-01

    Timelapse airborne lidar collected over 4 years on the coastal Trinity River in east Texas, USA, shows profound spatial variability in point bar shape and growth as well as cut bank erosion in channel bends. The difference map covers 88 river kilometers with 54 bends included in the study. The transition from quasi-uniform flow into backwater affected flow occurs about halfway through the survey, and is accompanied by distinct changes in point bar growth and cut bank erosion. Within a single bend, the extent and amount of point bar deposition and outer-bank erosion are typically well-correlated, implying that bank pull and bar push are intimately linked. Point bar depositional area decreases from an average of about 72,000 square meters in the region of quasi uniform flow down to less than 20,000 square meters before the bars become completely subaqueous in the backwater zone. The volume of sediment deposited on the sub-aerial bars drops by about 64% throughout the survey reach. The volume of sediment eroded from cutbanks behaves similarly. These trends nicely coincide with results from Smith 2012 that show a sharp decrease in the lateral migration rate of the channel in the backwater zone of the Trinity River. Results from this study help to deepen the understanding of the system's morphodynamics by connecting changes in the geomorphology with river bend kinematics, hydraulics and sediment transport.

  10. Analytical determination of coupled bending-torsion vibrations of cantilever beams by means of station functions

    NASA Technical Reports Server (NTRS)

    Mendelson, Alexander; Gendler, Selwyn

    1951-01-01

    A method based on the concept of station functions is presented for calculating the modes and the frequencies of nonuniform cantilever beams vibrating in torsion, bending, and coupled bending-torsion motion. The method combines some of the advantages of the Rayleigh-Ritz and Stodola methods, in that a continuous loading function for the beam is used, with the advantages of the influence-coefficient method, in that the continuous loading function is obtained in terms of the displacements of a finite number of stations along the beam.

  11. VIEW, LOOKING NORTHWEST, OF MIANUS RIVER PUMP STATION AND MIANUS ...

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

    VIEW, LOOKING NORTHWEST, OF MIANUS RIVER PUMP STATION AND MIANUS RIVER DAM. AT THE LEFT END OF THE DAM IS A FISH LADDER INSTALLED IN 1993 - New York, New Haven & Hartford Railroad, Mianus River Pumping Station, River Road & Boston Post Road, Greenwich, Fairfield County, CT

  12. 13. VIEW FROM POTOMAC RIVER BRIDGE PLATFORM WEST TOWARDS STATION. ...

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

    13. VIEW FROM POTOMAC RIVER BRIDGE PLATFORM WEST TOWARDS STATION. HARPERS FERRY DEPOT IS ON LEFT, NORTH TRACK WAITING STATION IS ON RIGHT. - Baltimore & Ohio Railroad, Harpers Ferry Station, Potomac Street, Harpers Ferry, Jefferson County, WV

  13. Title V Operating Permit: XTO Energy, Inc. - River Bend Dehydration Site

    EPA Pesticide Factsheets

    Initial Title V Operating Permit (Permit Number: V-UO-000026-2011.00) and the Administrative Permit Record for the XTO Energy, Inc., River Bend Dehydration Site, located on the Uintah and Ouray Indian Reservation.

  14. Draft Part 71 Permit: XTO Energy Inc. - River Bend Dehydration Site

    EPA Pesticide Factsheets

    Draft Title V Operating Permit, statement of basis, public notice bulletin, and the administrative permit docket (application and other supporting documents) for the Draft Part 71 Permit for XTO Energy Inc. - River Bend Dehydration Site

  15. Draft Part 71 Permit: XTO Energy Inc. - River Bend Dehydration Site

    EPA Pesticide Factsheets

    Draft Operating Permit (Permit Number: V-UO-000026-2011.00), statement of basis, public notice bulletin, and the administrative permit docket (application and other supporting documents) for the XTO Energy Inc. - River Bend Dehydration Site

  16. Autogenic Scour and Channel Widening in Sharp Bends of the River Mahakam

    NASA Astrophysics Data System (ADS)

    Hoitink, T.; Vermeulen, B.; van Berkum, S.; Hidayat, H.; Labeur, R. J.

    2014-12-01

    Field evidence of the River Mahakam reveals autogenic scour and channel widening in a series of sharp bends. An integral analysis of a 300 km reach of the river is presented, including a comprehensive survey of the river banks, delineation of the river corridor from radar observations, Large Eddy Simulations of observed flow patterns, and a geometric analysis of planform and depth information. Scour depths strongly exceed what can be expected based on existing understanding of sharp bends, and are highly correlated with curvature. Histograms of the occurrence of erosive, stable, advancing, and bar-type banks as a function of curvature quantify the switch from a mildly curved bend regime to a sharp bend regime. In mild bends, outer banks erode and inner banks advance. In sharp bends the erosion pattern inverts. Outer banks stabilize or advance, while inner banks erode. In sharply curved river bends, bars occur near the outer banks that become less erosive for higher curvatures. Inner banks become more erosive for higher curvatures, but nevertheless accommodate the larger portion of exposed bars. Soil processes may play a crucial role in the formation of sharp bends, which is inferred from iron and manganese concretions observed in the riverbanks, indicating ferric horizons and early stages of the formation of plinthic horizons. Historical topographic maps show the planform activity of the river is low, which may relate to the scours slowing down planimetric development. The occurrence of exceptionally deep scours is attributed to downflow near the scour exceeding 12 cm/s, increasing the bed shear stress. The downflow, in turn, is explained from the cross-sectional area increase, which is shown to be important in generating adverse surface gradients driving flow recirculation in the Large Eddy Simulations. Strong secondary flow distorts the vertical pressure distribution that is no longer hydrostatic. The downflow advects longitudinal momentum, moving the core of the

  17. INTERIOR VIEW OF MIANUS RIVER PUMP STATION LOOKING SOUTHEAST. THE ...

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

    INTERIOR VIEW OF MIANUS RIVER PUMP STATION LOOKING SOUTHEAST. THE CYLINDRICAL TANKS ON THE RIGHT SIDE OF THE PHOTOGRAPH ARE SAND-GRAVEL FILTERS. THE DIESEL POWERED PUMPS LOCATED IN THE CENTER LEFT FOREGOUND SUPPLIED FRESH WATER THROUGH A 16" LINE TO THE POWER PLANT BOILERS LOCATED ONE MILE SOUTH OF THE PUMP STATION - New York, New Haven & Hartford Railroad, Mianus River Pumping Station, River Road & Boston Post Road, Greenwich, Fairfield County, CT

  18. 16. YAZOO BACKWATER PUMPING STATION MODEL, YAZOO RIVER BASIN. MECHANICAL ...

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

    16. YAZOO BACKWATER PUMPING STATION MODEL, YAZOO RIVER BASIN. MECHANICAL AND HYDRAULIC ENGINEERS EXAMINING MODEL PUMPS. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  19. 19. YAZOO BACKWATER PUMPING STATION MODEL, YAZOO RIVER BASIN. ELECTRONICS ...

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

    19. YAZOO BACKWATER PUMPING STATION MODEL, YAZOO RIVER BASIN. ELECTRONICS ENGINEER AT DATA COLLECTION COMPUTER ROOM. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  20. 15. YAZOO BACKWATER PUMPING STATION MODEL, YAZOO RIVER BASIN (MODEL ...

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

    15. YAZOO BACKWATER PUMPING STATION MODEL, YAZOO RIVER BASIN (MODEL SCALE: 1' = 26'). - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  1. Extreme sediment pulses generated by bend cutoffs along a large meandering river

    NASA Astrophysics Data System (ADS)

    Zinger, Jessica A.; Rhoads, Bruce L.; Best, James L.

    2011-10-01

    In meandering rivers, bend cutoffs have long been recognized as an important mechanism of change in the path of the channel. Meander bend cutoffs can develop by the progressive migration of an elongated bend onto itself, which forms a neck cutoff, or by the erosion of a new channel across the neck of the bend, which is known as a chute cutoff. River cutoffs affect channel navigation, and form meander scars and oxbow lakes in river floodplains, which are important habitats for riparian ecosystems. The importance of cutoff processes in meander dynamics is well established, but the effects of cutoffs on overall sediment flux are poorly characterized. Here we use aerial imagery, global positioning system mapping and measurements of channel bathymetry to estimate the amount of sediment released by two chute cutoffs on the Wabash River in the Midwestern USA. We find that each event triggered the rapid delivery of sediment into the river, at rates that are one to five orders of magnitude larger than those produced by lateral migration of individual bends. We find that much of this material was deposited immediately downstream, at the confluence of the Wabash and Ohio rivers, which led to significant changes in channel morphology. This sedimentation ultimately impeded barge traffic and necessitated extensive dredging.

  2. Composition of Age-0 Fish Assemblages in the Apalachicola River, River Styx, and Battle Bend, Florida

    USGS Publications Warehouse

    Walsh, Stephen J.; Buttermore, Elissa N.; Burgess, O. Towns; Pine, William E.

    2009-01-01

    Light traps were used to sample the age-0 year class of fish communities in the Apalachicola River and associated floodplain water bodies of River Styx and Battle Bend, Florida, in 2006-2007. A total of 629 light traps were deployed during the spring and early summer months (341 between March 15 and June 6, 2006; 288 between March 9 and July 3, 2007). For combined years, 13.8 percent of traps were empty and a total of 20,813 age-0 fish were captured representing at least 40 taxa of 29 genera and 16 families. Trap catches were dominated by relatively few species, with the most abundant groups represented by cyprinids, centrarchids, percids, and catostomids. Six taxa accounted for about 80 percent of all fish collected: Micropterus spp. (28.9 percent), Notropis texanus (28.9 percent), Lepomis macrochirus (7.9 percent), Carpiodes cyprinus (6.2 percent), Cyprinidae sp. (4.6 percent), and Minytrema melanops (4.2 percent). Based on chronological appearance in light traps and catch-per-unit effort, including data from previous years of sampling, peak spawning periods for most species occurred between early March and mid-June. A complementary telemetry study of pre-reproductive adults of select target species (Micropterus spp., Lepomis spp., and M. melanops) revealed distinct patterns of habitat use, with some individual fish exclusively utilizing mainstem river habitat or floodplain habitat during spawning and post-spawning periods, and other individuals migrating between habitats. A comparison of light-trap catches between a pre-enhancement, high-water year (2003) and post-enhancement, low-water year (2007) for the oxbow at Battle Bend revealed some difference in community composition, with slightly greater values of diversity and evenness indices in 2007. Two dominant species, Lepomis macrochirus and Micropterus salmoides, were substantially greater in relative abundance among all age-0 fish collected in 2007 in comparison to 2003. Excavation of sediments at the mouth

  3. An integrated approach to investigate the reach-averaged bend scale dynamics of large meandering rivers

    NASA Astrophysics Data System (ADS)

    Monegaglia, Federico; Henshaw, Alex; Zolezzi, Guido; Tubino, Marco

    2016-04-01

    Planform development of evolving meander bends is a beautiful and complex dynamic phenomenon, controlled by the interplay among hydrodynamics, sediments and floodplain characteristics. In the past decades, morphodynamic models of river meandering have provided a thorough understanding of the unit physical processes interacting at the reach scale during meander planform evolution. On the other hand, recent years have seen advances in satellite geosciences able to provide data with increasing resolution and earth coverage, which are becoming an important tool for studying and managing river systems. Analysis of the planform development of meandering rivers through Landsat satellite imagery have been provided in very recent works. Methodologies for the objective and automatic extraction of key river development metrics from multi-temporal satellite images have been proposed though often limited to the extraction of channel centerlines, and not always able to yield quantitative data on channel width, migration rates and bed morphology. Overcoming such gap would make a major step forward to integrate morphodynamic theories, models and real-world data for an increased understanding of meandering river dynamics. In order to fulfill such gaps, a novel automatic procedure for extracting and analyzing the topography and planform dynamics of meandering rivers through time from satellite images is implemented. A robust algorithm able to compute channel centerline in complex contexts such as the presence of channel bifurcations and anabranching structures is used. As a case study, the procedure is applied to the Landsat database for a reach of the well-known case of Rio Beni, a large, suspended load dominated, tropical meandering river flowing through the Bolivian Amazon Basin. The reach-averaged evolution of single bends along Rio Beni over a 30 years period is analyzed, in terms of bend amplification rates computed according to the local centerline migration rate. A

  4. Hydrogeologic characterization of the Brazos River Alluvium Aquifer, Bosque County to Fort Bend County, Texas

    USGS Publications Warehouse

    Shah, Sachin D.; Houston, Natalie A.; Braun, Christopher L.

    2007-01-01

    Introduction The Brazos River alluvium aquifer underlies the Brazos River in Texas from Bosque County to Fort Bend County. The aquifer, one of 21 minor aquifers in the State, supplies water for irrigation, domestic, stock, and commercial use. The Brazos River alluvium aquifer likely will become more important in the future as demand for water increases statewide. A thorough understanding of the hydrogeology of the alluvium aquifer will be the foundation for future studies in the area. During October 2006-April 2007, the U.S. Geological Survey, in cooperation with the Texas Water Development Board, conducted a study to delineate the altitude of the top, altitude of the base, and thickness of the Brazos River alluvium aquifer, and to compile and summarize available hydraulic property (specific capacity, transmissivity, and hydraulic conductivity) data. A digital elevation model was used as the altitude of the top of the aquifer. The altitude of the base of the aquifer was generated using data from wells. The study area encompasses the Brazos River alluvium aquifer in parts of Bosque, Hill, McLennan, Falls, Robertson, Milam, Brazos, Burleson, Grimes, Washington, Waller, Austin, and Fort Bend Counties and a 1.5-mile-wide lateral buffer adjacent to the aquifer. The results of this study will be used by the Texas Water Development Board for input into a ground-water availability model.

  5. Incision of the Yangtze River at the First Bend Determined by Three-Nuclide Burial Dating

    NASA Astrophysics Data System (ADS)

    McPhillips, D. F.; Hoke, G. D.; Rood, D. H.; Bierman, P. R.

    2015-12-01

    On the southeast margin of the Tibetan Plateau, the evolution of the Yangtze River and its major tributaries has become an important source of data for investigating geodynamics. In particular, the timing of river incision is frequently interpreted as a proxy for the timing of surface uplift in the absence of structural evidence. We investigate the timing of the incision of the gorge at the First Bend using cosmogenic nuclide burial dating of coarse, quartz sediments from caves. Sediments were deposited when the caves were near river level and subsequently abandoned as the river incised. To resolve burial ages >5 Ma, we measured the radionuclides 10Be and 26Al, and the stable nuclide 21Ne. Results from 4 caves show that 26Al and 10Be concentrations are an order of magnitude lower in abandoned cave samples than in a river-level cave sample where deposition is active (10Be: 1.3x104 and 3.4x105 at/g). In contrast, 26Al/10Be ratios in all caves are ≥6.2 and indistinguishable within error. 21Ne concentrations range from 2.1x106 to 7.8x106 at/g. The results are consistent with an old age for the abandoned cave deposits, such that most of the radionuclides initially present have decayed and the concentrations that we measure today are the result of millions of years of exposure to muons. We solve for burial ages, taking into account in situ muogenic production, and find that the majority of the gorge (1 km) was likely incised between ~12 and 9 Ma. The results also require that the rate of river incision declined after the gorge was cut below the lowest elevation cave at 9 Ma. Inverse modeling of published low-temperature thermochronology (Ouimet et al., 2010) supports our burial age results. River capture near the First Bend, which likely integrated the modern Yangtze, likely occurred prior to the mid-Miocene incision of the gorge. In view of the geographic position of the First Bend—just downslope from the southeast margin of the Plateau—it is difficult to explain

  6. 50. VIEW OF CENTRAL CONTROL STATION AND VISITOR CENTER/RIVER SIDES ...

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

    50. VIEW OF CENTRAL CONTROL STATION AND VISITOR CENTER/RIVER SIDES (Visitor Center Building constructed after field negatives were taken and numbered.) - Mississippi River 9-Foot Channel Project, Lock & Dam No. 11, Upper Mississippi River, Dubuque, Dubuque County, IA

  7. Research station to aid multidisciplinary study of Upper Mississippi River

    NASA Astrophysics Data System (ADS)

    Nakato, Tatsuaki

    IIHR-Hydroscience and Engineering (formerly Iowa Institute of Hydraulic Research) of the University of Iowa's College of Engineering is establishing a Mississippi Riverside Environmental Research Station (MRERS) to provide opportunities for researchers and educators around the world to study river ecosystems in a multidisciplinary setting. MRERS will provide state-of-the-art facilities to study diverse facets of the upper Mississippi River to better understand river ecosystems and their response to natural events and human activities. It will also provide students at all levels with hands-on experience as well as opportunities for public education. In light of recent flooding in the region last spring, establishment of MRERS is timely MRERS will bring a truly multidisciplinary approach to understanding and planning for one of the country's most important natural resources: the mighty Mississippi.

  8. Role of river bends for the formation and evolution of channel bedforms: Combined field studies and numerical modeling from the tidally influenced zones of the Yellow River, China, and Mississippi River, USA.

    NASA Astrophysics Data System (ADS)

    Ma, H.; Nittrouer, J. A.; Moodie, A.; Calson, B.; Parker, G.

    2015-12-01

    River bedforms represent the unstable interface between fluid flow and the granular channel bed, and these features play an important role for modifying flow resistance and sediment transport rates, and thus influencing river morphology. Although widely observed in natural rivers, bedforms are difficult to measure quantitatively and are rarely connected to other fluvial morphological processes. This study presents high-resolution channel bathymetric data from the tidally influenced, lowermost Yellow River, China, collected using a multibeam swath profiler. Repeat surveys were conducted over rising and flood discharge conditions, which is the first such kind of survey in Yellow River. The bathymetry data show that for all water discharges, a flat bed, devoid of a thalweg or dunes, persists within straight-reach segments near the bends of the Yellow River, despite the bed consisting of fine sand. Interestingly, in bend segments, the channel deepens, and linear dunes develop. Moreover, as the water discharge increases over time, the edge of dune field contained in the bend segments propagates into the adjacent upstream and downstream straight-reach segments. In contrasting case study, Nittrouer et al. (2008) reported persistent dune field in the straight reaches of the tidally influenced Mississippi River; however these dunes disappear in neighboring river bends. Based on the two cases of the Yellow and Mississippi Rivers, which have fundamentally different conditions of water-to-sediment discharge ratios, the threshold condition of bedform formation and stability are evaluated, and connected to local conditions of river bend morphology. This work improves the understanding of the co-evolution of bedforms and flow conditions in river bends, which are intertwined and important morphological processes that affect fluvial-deltaic sediment transport dynamics. In addition, the straight-bend structure is a basic element of river morphology, and so the results of this study

  9. Cultural Resource Survey of Carrollton Bend Revetment, Mississippi River M-105.7 to 101.7-L, Jefferson and Orleans Parishes, Louisiana

    DTIC Science & Technology

    1993-02-26

    CARROLLTON BEND REVETMENT, MISSISSIPPI RIVER M-105.7 TO 101.7-., JEFFERSON AND ORLEANS PARISHES, LOUISIANA February 1993 FINAL REPORT DTIC,CT, R. Christopher...CULTURAL RESOURCE SURVEY OF CARROLLTON BEND REVETMENT, MISSISSIPPI RIVER M-105.7 TO 101.7-L, JEFFERSON AND ORLEANS PARISHES, LOUISIANA 12-PERSONAL AUTHOR(S...survey of the Carrollton Bend levetment, Jefferson and Orteant4 parishes, Louisiana. The project was undertaken by P.. Christopher Goodwin

  10. 77 FR 53913 - River Bend Industries, LLC, Including On-Site Leased Workers From FirstStaff, Trac Staffing, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-04

    ... FirstStaff, Trac Staffing, and Worksource, Inc., Fort Smith, Arkansas; Amended Certification Regarding... Industries, LLC including on-site leased workers from FirstStaff, Trac Staffing, Worksource, Inc., Fort Smith... at the Fort Smith, Arkansas location of River Bend Industries, LLC. The Department has determined...

  11. Applying a Model of Curvature-Driven Bend Migration Developed for Alluvial Rivers to a Gravel-Bedded River With Reaches of Exposed Bedrock

    NASA Astrophysics Data System (ADS)

    Narinesingh, P.; Pizzuto, J. E.

    2009-12-01

    The South River, Virginia, a sinuous, gravel-bedded river influenced by frequent bedrock exposures, appears at first glance to be meandering. However, when its planform statistics are compared to a freely meandering river (the Teklanika River, Alaska), systematic differences become apparent. Bends of the South River have shorter lengths, longer radii of curvatures, a distinctive meander wavelength spectrum, and a lower fractal dimension of D = 1.11 than those of the Teklanika River. Sixty five percent of the length of South River in the study area consists of sections with exposed bedrock (either on the bed or the banks) and islands. Alluvial floodplains of varying lengths are scattered between sections of bedrock and islands, accounting for the remaining 35% of the study reach. In these areas, the South River displays sinuosity values that may be as high as 2.5. Within the alluvial reaches, aerial photographs from 1937 and 2005 document significant channel migration. Driven by the need to quantify the flux of mercury-contaminated sediments entering the river through bank erosion, we applied the bend migration model of Johannesson and Parker (1989). The model, when schematized for hydraulics of the alluvial sections of the South River and calibrated to the total area of erosion mapped from aerial photographs, correctly predicts 45% of the observed locations of erosion as mapped from the aerial photographs and observed in the field. The total area of erosion computed using the predicted near-bank excess velocity is within 14% of that mapped. According to a non-parametric Kruskal-Wallis test, the predicted areas of erosion along the river are not significantly different from those defined by the historical aerial photographs (P >= 0.05, two tailed test). These results suggest that curvature dependent hydraulic models for alluvial rivers may provide useful predictions of total erosion of alluvium on mixed bedrock/alluvial rivers like the South River. However, improved

  12. Flow structure caused by a local cross-sectional area increase and curvature in a sharp river bend

    NASA Astrophysics Data System (ADS)

    Vermeulen, B.; Hoitink, A. J. F.; Labeur, R. J.

    2015-09-01

    Horizontal flow recirculation is often observed in sharp river bends, causing a complex three-dimensional flow structure with large implications for the morphological and planimetric development of meanders. Several field observations in small-scale systems show that sharp bends are often found in association with a strong increase in cross-sectional area, the deposition of outer bank benches, and reattachment bars near the inner bank. Recent studies show that these bends can also occur in large-scale systems. In this study, we present field measurements of a sharp bend in the Mahakam River, East Kalimantan, Indonesia. The cross-sectional area increases by a factor of 3 compared with the reach-averaged cross-sectional area. Along a river reach of about 150 km, cross-sectional area correlates strongly with curvature. The field measurements are analyzed together with the results from numerical simulation with a three-dimensional finite element model, which yields a comprehensive view of the intricate flow structure. In turn, the model is used to validate a new equation that captures the water surface topography dependence on cross-sectional area variation and curvature. The results show the importance of the increase in cross-sectional area in the development of horizontal recirculation. Vertical acceleration of the flow into the scour causes the pressure to deviate from a hydrostatic pressure distribution. Strong downflow (up to 12 cm s-1) advects longitudinal momentum toward the bed, causing the flow to concentrate in the lower part of the cross section. This increases the velocity magnitude throughout the cross section, which is expected to maintain the large scour depth found in several bends along the Mahakam River.

  13. Flow structure caused by a local cross-sectional area increase and curvature in sharp river bends

    NASA Astrophysics Data System (ADS)

    Vermeulen, B.

    2015-12-01

    Horizontal flow recirculation is often observed in sharp river bends, causing a complex three-dimensional flow structure with large implications for the morphological and planimetric development of meanders. Several field observations in small scale systems show that sharp bends are often found in association with a strong increase in cross-sectional area, the deposition of outer bank benches and reattachment bars near the inner bank. Recent studies show that these bends can also occur in large scale systems. In this study, we present field measurements of a sharp bend in the Mahakam River, East Kalimantan, Indonesia. The cross-sectional area increases by a factor of three compared with the reach averaged cross-sectional area. Along a river reach of about 150 km, cross-sectional area correlates strongly with curvature. The field measurements are analyzed together with the results from numerical simulation with a 3D finite element model, which yields a comprehensive view of the intricate flow structure. In turn, the model is used to validate a new equation that captures the water surface topography dependence on cross-sectional area variation and curvature. The results show the importance of the increase in cross-sectional area in the development of horizontal recirculation. Vertical acceleration of the flow into the scour causes the pressure to deviate from a hydrostatic pressure distribution. Strong downflow (up to 12 cm/s) advects longitudinal momentum towards the bed, causing the flow to concentrate in the lower part of the cross-section. This increases the velocity magnitude throughout the cross-section, which is expected to maintain the large scour depth found in several bends along the Mahakam River.

  14. Base flow (1966-2005) and streamflow gain and loss (2006) of the Brazos River, McLennan County to Fort Bend County, Texas

    USGS Publications Warehouse

    Turco, Michael J.; East, Jeffery W.; Milburn, Matthew S.

    2007-01-01

    During 2006?07, the U.S. Geological Survey (USGS), in cooperation with the Texas Water Development Board, did a study to quantify historical (water years 1966?2005) base flow and streamflow gains and losses from two streamflow-measuring surveys (March and August 2006) in the Brazos River from McLennan County to Fort Bend County, Texas. The Brazos River is hydraulically connected to the Brazos River alluvium aquifer, which in turn is hydraulically connected to several underlying aquifers, the outcrops of which occur in laterally adjacent layers generally parallel to the coast (major aquifers, Carrizo-Wilcox and Gulf Coast, and minor aquifers, Queen City, Sparta, and Yegua-Jackson). Hydrograph separation was done using the USGS computer program Hydrograph Separation and Analysis with historical streamflow from 10 USGS gaging stations, three on the Brazos River and seven on selected tributaries to the Brazos River. Streamflow data for computation of gains and losses were collected in March 2006 from 36 sites on the Brazos River and 19 sites on 19 tributaries to the Brazos River; and in August 2006 from 28 sites on the Brazos River and 16 sites on tributaries. Hydrograph separation and associated analyses indicate an appreciable increase in base flow as a percentage of streamflow in the reach of the Brazos River that crosses the outcrops of the Carrizo-Wilcox, Queen City, Sparta, and Yegua-Jackson aquifers compared to that in the adjacent upstream reach (on average from about 43 percent to about 60 percent). No increase in base flow as a percentage of streamflow in the reach of the Brazos River crossing the Gulf Coast aquifer compared to that in the adjacent upstream reach was indicated. Streamflow gains and losses computed for March 2006 for 35 reaches defined by pairs of sites on the Brazos River indicated that five reaches were verifiably gaining streamflow (computed gain exceeded potential flow measurement error) and none were verifiably losing streamflow. Four of

  15. Morphology and sedimentology of a central Brazos River point bar, Boxley Bend, Brazos County, Texas

    SciTech Connect

    Connolly, W.M.; Mazzullo, J.

    1986-09-01

    A reconnaissance of Brazos River point bars reveals great variety in their morphology and sedimentology, owing to the complex interaction of climate, local hydrography, and local sediment sources. This paper presents the first in a series of studies of point bars of the Brazos River and concentrates on the Boxley Bend point bar near Snook, Texas. The summer morphology of the point bar is complex, consisting of an upper and lower tier separated by a scarp but connected by a central ramp. The surfaces of the lower tier and ramp display numerous large gravel bars and shallow scour pools as well as low-amplitude sand waves, ripples, and current lineations. In cross section, the lower tier and ramp are characterized by (1) trough cross-bedded, medium to fine sand produced by megaripple migration during floods; (2) massive gravel beds, the product of formation and migration of gravel bars during floods; and (3) fine rippled sand and clay drapes formed during falling flood. The surface of the upper tier displays ripple-laminated eolian sand and deflation deposits of mud clasts. In cross section, the upper tier is characterized by thick beds of horizontally stratified fine sand. During the winter, the entire surface of the point bar is covered by large (2 m high) transverse bars separated by deep scour troughs. Transverse bars migrate into the troughs to produce a sequence of fine sand with backflow ripple cross-stratification overlain by thick beds of tabular cross-bedded medium sand. The transverse bars appear to be transitory features with little net effect on sedimentation, because they are removed from the surface of the point bar by summertime.

  16. Population trends, bend use relative to available habitat and within-river-bend habitat use of eight indicator species of Missouri and Lower Kansas River benthic fishes: 15 years after baseline assessment

    USGS Publications Warehouse

    Wildhaber, Mark L.; Yang, Wen-Hsi; Arab, Ali

    2016-01-01

    A baseline assessment of the Missouri River fish community and species-specific habitat use patterns conducted from 1996 to 1998 provided the first comprehensive analysis of Missouri River benthic fish population trends and habitat use in the Missouri and Lower Yellowstone rivers, exclusive of reservoirs, and provided the foundation for the present Pallid Sturgeon Population Assessment Program (PSPAP). Data used in such studies are frequently zero inflated. To address this issue, the zero-inflated Poisson (ZIP) model was applied. This follow-up study is based on PSPAP data collected up to 15 years later along with new understanding of how habitat characteristics among and within bends affect habitat use of fish species targeted by PSPAP, including pallid sturgeon. This work demonstrated that a large-scale, large-river, PSPAP-type monitoring program can be an effective tool for assessing population trends and habitat usage of large-river fish species. Using multiple gears, PSPAP was effective in monitoring shovelnose and pallid sturgeons, sicklefin, shoal and sturgeon chubs, sand shiner, blue sucker and sauger. For all species, the relationship between environmental variables and relative abundance differed, somewhat, among river segments suggesting the importance of the overall conditions of Upper and Middle Missouri River and Lower Missouri and Kansas rivers on the habitat usage patterns exhibited. Shoal and sicklefin chubs exhibited many similar habitat usage patterns; blue sucker and shovelnose sturgeon also shared similar responses. For pallid sturgeon, the primary focus of PSPAP, relative abundance tended to increase in Upper and Middle Missouri River paralleling stocking efforts, whereas no evidence of an increasing relative abundance was found in the Lower Missouri River despite stocking.

  17. From meander bend to oxbow lake: flow, channel morphology and sedimentology of an evolving chute cutoff on the Wabash River, IL-IN

    NASA Astrophysics Data System (ADS)

    Zinger, J. A.; Rhoads, B. L.; Best, J. L.; Johnson, K.

    2012-12-01

    Chute channels develop on meandering rivers in a wide variety of environments, and in many cases result in bend cutoff and formation of an oxbow lake. During the transition from active meander bend to oxbow lake, the chute channel and original bend create a paired bifurcation-confluence unit. Here, we present field documentation of the evolving flow structure within a recent chute cutoff on the Wabash River, IL-IN, focusing on the bifurcation located on the upstream limb of the original bend. Previous studies indicate that this is the location of greatest sedimentation rates prior to complete plugging of the bend (e.g. Shields & Abt, 1989). We seek to isolate the fundamental processes causing rapid sedimentation in the upstream limb of the bend, using repeated hydroacoustic measurements of bed elevation and three-dimensional flow velocity at several key cross-sections. We also employ differential GPS surveys of channel banklines, analysis of aerial photographs and sampling of sediment on exposed bars at low flow, to aid interpretations of the cross-sectional data. This paper will detail the co-evolution of flow structure and channel morphology at this site and examine the coherent patterns of erosion and deposition responsible for oxbow lake formation. Reference: Shields, FD; Abt, SR (1989). Sediment deposition in cutoff meander bends and implications for effective management. Regulated Rivers: Research & Management 4, 381-396.

  18. Proposed Synthetic Minor NSR Permit: Anadarko Uintah Midstream, LLC - White River Compressor Station

    EPA Pesticide Factsheets

    Proposed synthetic minor NSR permit, public notice bulletin, and administrative permit docket for the Anadarko Uintah Midstream, LLC, White River Compressor Station, located on Uintah and Ouray Indian Reservation in Utah.

  19. Geologic and hydrogeologic information for a geodatabase for the Brazos River Alluvium Aquifer, Bosque County to Fort Bend County, Texas

    USGS Publications Warehouse

    Shah, Sachin D.; Houston, Natalie A.

    2007-01-01

    During July-October 2006, the U.S. Geological Survey (USGS), in cooperation with the Texas Water Development Board (TWDB), developed geologic and hydrogeologic information for a geodatabase for use in development of a Groundwater Availability Model (GAM) of the Brazos River alluvium aquifer along the Brazos River from Bosque County to Fort Bend County, Texas. The report provides geologic and hydrogeologic information for a study area that encompasses the Brazos River alluvium aquifer, a 1/2-mile-wide lateral buffer surrounding the aquifer, and the rocks immediately underlying the aquifer. The geodatabase involves use of a thematic approach to create layers of feature data using a geographic information system. Feature classes represent the various types of data that are keyed to spatial location and related to one another within the geodatabase. The 1/2-mile-wide buffer surrounding the aquifer was applied to include data from wells constructed primarily in alluvium but outside the boundary of the Brazos River alluvium aquifer. A 1/2- by 1/2-mile grid was generated on the study area to facilitate uniform distribution of data for eventual input into the GAM. Data were compiled primarily from drillers and borehole geophysical logs from government agencies and universities, hydrogeologic sections and maps from published reports, and agency files. The geodatabase contains 450 points with geologic data and 280 points with hydrogeologic data.

  20. Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry.

    PubMed

    Gleason, Colin J; Smith, Laurence C

    2014-04-01

    Rivers provide critical water supply for many human societies and ecosystems, yet global knowledge of their flow rates is poor. We show that useful estimates of absolute river discharge (in cubic meters per second) may be derived solely from satellite images, with no ground-based or a priori information whatsoever. The approach works owing to discovery of a characteristic scaling law uniquely fundamental to natural rivers, here termed a river's at-many-stations hydraulic geometry. A first demonstration using Landsat Thematic Mapper images over three rivers in the United States, Canada, and China yields absolute discharges agreeing to within 20-30% of traditional in situ gauging station measurements and good tracking of flow changes over time. Within such accuracies, the door appears open for quantifying river resources globally with repeat imaging, both retroactively and henceforth into the future, with strong implications for water resource management, food security, ecosystem studies, flood forecasting, and geopolitics.

  1. 33 CFR 165.554 - Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County, Pennsylvania. 165.554 Section 165.554 Navigation and... Areas Fifth Coast Guard District § 165.554 Security Zone; Three Mile Island Generating Station...

  2. 33 CFR 165.554 - Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County, Pennsylvania. 165.554 Section 165.554 Navigation and... Areas Fifth Coast Guard District § 165.554 Security Zone; Three Mile Island Generating Station...

  3. 33 CFR 165.554 - Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County, Pennsylvania. 165.554 Section 165.554 Navigation and... Areas Fifth Coast Guard District § 165.554 Security Zone; Three Mile Island Generating Station...

  4. 33 CFR 165.554 - Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County, Pennsylvania. 165.554 Section 165.554 Navigation and... Areas Fifth Coast Guard District § 165.554 Security Zone; Three Mile Island Generating Station...

  5. 33 CFR 165.554 - Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; Three Mile Island Generating Station, Susquehanna River, Dauphin County, Pennsylvania. 165.554 Section 165.554 Navigation and... Areas Fifth Coast Guard District § 165.554 Security Zone; Three Mile Island Generating Station...

  6. 78 FR 75386 - Entergy Operations, Inc.; Combined License Application for River Bend Station Unit 3, Exemption...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-11

    ... CONTACT: John Klos, Office of New Reactors, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001... and receipt of license, or operate the facility. The target of Section I.5 of the rule were those... implementation among licensees; and modify certain requirements to be more effective and efficient. Since plant...

  7. 78 FR 53482 - Entergy Operations, Inc., River Bend Station, Unit 1; Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ... interpretation of P a as defined in Appendix J has no relation to security issues. Therefore, the common defense... determined that the granting of this exemption will not have a significant effect on the quality of the human...

  8. Influence of Channel Morphology on Flow Hydraulics in a Compound Meander Bend of the Lower Brazos River, Texas

    NASA Astrophysics Data System (ADS)

    Hales, B. U.; Guneralp, I.; Filippi, A. M.

    2013-12-01

    At a meander-bend scale, process-form interactions between channel morphology and flow hydraulics generate unique features called geomorphic units, such as pools, sediment bars, and backwater regions. Geomorphic units play an important role as distinct habitats for aquatic species. In this study, we investigate channel morphology and flow structure of an incised meander bend on the lower Brazos River, Texas, to inform aquatic habitat assessment. The bend represents the characteristics of sand-bed and high-amplitude meandering rivers and contains a localized bank-protection structure along its cutbank. We examine: 1) the spatial characteristics of channel morphology (i.e., geomorphic units); 2) spatial characteristics of flow hydraulics in relation to geomorphic units at low- (Q1), medium- (Q2), and high- (Q3) discharge conditions; and 3) the influence of channel morphology on flow hydraulics within this meander bend. We utilize bathymetric and hydraulic surveys conducted using Acoustic Doppler Current Profiler (ADCP) and simultaneously collected bed-sediment samples. To characterize channel morphology, we use a digital terrain model (DTM) of the bend that we generate by fusing our bathymetric data and an airborne interferometric synthetic aperture radar (InSAR)-derived DTM. We examine flow hydraulics by performing quasi 3-D hydraulic modeling. Results show that channel morphology has a strong influence on the spatial distribution of hydraulic parameters, including water depth, flow velocities, Froude number, and helix strength. At Q1, the emergent mid-channel bar forces flow divergence/convergence and acts as a macro-roughness structure. High flow velocity concentrates in the deeper and narrower sub-channel along the cutbank side. At Q2, the location of the mid-channel bar shifts toward the point bar, forming a new chute sub-channel. Highest flow velocities are still concentrated in the permanent sub-channel along the cutbank, but shift downstream toward the exit

  9. Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry

    PubMed Central

    Gleason, Colin J.; Smith, Laurence C.

    2014-01-01

    Rivers provide critical water supply for many human societies and ecosystems, yet global knowledge of their flow rates is poor. We show that useful estimates of absolute river discharge (in cubic meters per second) may be derived solely from satellite images, with no ground-based or a priori information whatsoever. The approach works owing to discovery of a characteristic scaling law uniquely fundamental to natural rivers, here termed a river’s at-many-stations hydraulic geometry. A first demonstration using Landsat Thematic Mapper images over three rivers in the United States, Canada, and China yields absolute discharges agreeing to within 20–30% of traditional in situ gauging station measurements and good tracking of flow changes over time. Within such accuracies, the door appears open for quantifying river resources globally with repeat imaging, both retroactively and henceforth into the future, with strong implications for water resource management, food security, ecosystem studies, flood forecasting, and geopolitics. PMID:24639551

  10. Knee-bend turn and compressed meandering on the Pam and Papum River due to tectonic forcing on the Sub-Himalaya of the Arunachal Himalaya, India

    NASA Astrophysics Data System (ADS)

    Devi, M.

    2009-04-01

    The Pam and Papum River gets originated from the Lesser Himalayan region,passes through the Sub-Himalaya and confluences at an obtuse angle in a prong shape, guided by ENE-WSW, WNW-ESE trending lineaments and join the mighty Brahmaputra River as the Burai River after following more or less as a straigth channel,from the north.It follows NE-SW to NW-SE trending lineaments. These rivers show compressed meandering and take knee-bend turnings on its river flow from north to south. Papum Syncline with its axial trend of ENE-WSW passes through the river channels of these rivers. The Pam River channel shows upright beddings on its left bank, as the Tippi Thrust, in which the Lower Siwaliks thrust upon the Middle and Upper Siwaliks, passes through the river channel had truncated northern flank of the Papum syncline. Structural elements of folding and fault movements disturbed the Pam and Papum River channels, leading to compressed meandering. With the onset of Tippi thrust, the north to southward flowing Pam River changed its course by taking knee bend turning from NW-SE to E-W to ENE- WSW direction following the fault trend. Columns of upright sandstone and pebbly beds protruded have also been observed along the left bank of the Pam River. Structural control of the river channel is also indicated by another set of the protruding sandstone beds observed on the right bank of the Pam River with no extension on the left bank is observed on its confluence with Jote Stream. Papum River also takes N-S to NW-SE channel with an obtuse angle turning guided by Tippi thrust and meets the Pam River in a Y-shaped joining along a 8km long NE-SW trending fault plane. Active tectonic activities uplifted Quaternary deposits of gravels, sand and silt in the study area. Left lateral movement is also evident from the offsetting of the Pam river at its confluence with Jote stream by about 300m. Intense activity of folding and faulting related to the proximal tectonics of the Himalayan foreland

  11. Evaluation of river water quality monitoring stations by principal component analysis.

    PubMed

    Ouyang, Ying

    2005-07-01

    The development of a surface water monitoring network is a critical element in the assessment, restoration, and protection of stream water quality. This study applied principal component analysis (PCA) and principal factor analysis (PFA) techniques to evaluate the effectiveness of the surface water quality-monitoring network in a river where the evaluated variables are monitoring stations. The objective was to identify monitoring stations that are important in assessing annual variations of river water quality. Twenty-two stations used for monitoring physical, chemical, and biological parameters, located at the main stem of the lower St. Johns River in Florida, USA, were selected for the purpose of this study. Results show that 3 monitoring stations were identified as less important in explaining the annual variance of the data set, and therefore could be the non-principal stations. In addition, the PFA technique was also employed to identify important water quality parameters. Results reveal that total organic carbon, dissolved organic carbon, total nitrogen, dissolved nitrate and nitrite, orthophosphate, alkalinity, salinity, Mg, and Ca were the parameters that are most important in assessing variations of water quality in the river. This study suggests that PCA and PFA techniques are useful tools for identification of important surface water quality monitoring stations and parameters.

  12. Changing Station Coverage in the Upper Colorado River Basin: Is This a Problem?

    NASA Astrophysics Data System (ADS)

    McAfee, S. A.; Woodhouse, C. A.; Morino, K.; Pederson, G. T.

    2015-12-01

    Almost 40 million people living in the arid western U.S. depend on the Colorado River. The high demand, recent drought, and paleoclimatic studies documenting long, severe droughts have spurred numerous studies on the drivers of Colorado River flow. Understanding low-frequency variability and trends in a large and complex basin like the Upper Colorado (UCRB), which contributes the vast majority of Colorado River flow, requires long, high-spatial resolution climatological records. However, researchers sometimes find discrepancies between long climate data products and hydrological records. One explanation for such disparities is the composition of the climate data record. The National Center for Environmental Information's Master Station History Report (MSHR) documents significant changes in the number and spatial distribution of weather stations within the UCRB. These shifts are reflected in the basin-average station elevation, which has varied by over 300m since 1950 and by over 365m since 1875. Strong elevation and aspect controls on both temperature and precipitation combined with the high degree of variability in station location could drive trends in gridded products in the absence of real climatological trends, although differences in base data, spatial resolution and gridding algorithms can complicate comparisons. Yet limiting analysis to only those stations with long, consistent records is impractical and would be problematic as station density in the early part of the record was not sufficient to characterize the basin. Here we document changes in station coverage within the UCRB and identify the degree to which coverage may have influenced climatic trends.

  13. Drainage areas for selected stream-sampling stations, Missouri River Basin

    USGS Publications Warehouse

    2006-01-01

    As part of the U.S. Geological Survey's (USGS) National Water-Quality Assessment Program (NAWQA), an investigation of the Missouri River Basin is being conducted to document trends in surface-water quality, specifically for trends in nutrients and suspended sediment. Surface-water samples were collected from streams at specific sampling stations. Water-quality characteristics at each station are influenced by the natural and cultural characteristics of the drainage area upstream from the sampling station. Efficient quantification of the drainage area characteristics requires a digital map of the drainage area boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital drainage-area boundary data for one stream-sampling station in the Missouri River Basin (MRB4) study area is included in this data release. The drainage divides were identified chiefly using 1:24,000-scale hypsography.

  14. Analysis of fixed-station water-quality data in the Umpqua River basin, Oregon

    USGS Publications Warehouse

    Rinella, J.F.

    1986-01-01

    An appraisal of surface water quality in the Umpqua River basin was made using existing monthly data collected by the Oregon Department of Environmental Quality and the U.S. Geological Survey in cooperation with the Douglas County Water Resources Survey. This appraisal was limited to interpretation of instantaneous monthly water quality data collected in the Umpqua River basin from water years 1974 to 1983. These data were used to compare water quality conditions throughout the basin and to determine if data collected from the NASQAN (National Stream Quality Accounting network) station are representative of upstream basin conditions. In general, data collected at the NASQAN station represent a composite of water quality from the North and South Umpqua Rivers. These river basins account for 82 % of the NASQAN station drainage. Water quality concentrations, loads, yields, and trends were statistically described and related to point source effluent loads and basin characteristics including geohydrology, hydrology, population, land use, and water use. Available point-and nonpoint-source data provided minimal information for determining cause-effect relations and for explaining observed trends in water quality; however, the data did indicate that the largest effluent discharges are located in the South Umpqua River basin in the Roseburg-Winston area. Instantaneous and annual flow weighted levels of specific conductance, phosphorus, organic plus ammonia nitrogen, nitrite plus nitrate, and fecal coliform bacteria are generally highest in the South Umpqua River near Roseburg. These high levels generally occur during the summer months when river flow is extremely low relative to flow in the North Umpqua River. The North Umpqua River has among the lowest constituent concentrations observed in the basin. (Lantz-PTT)

  15. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River, Ocean...

  16. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River, Ocean...

  17. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River, Ocean...

  18. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River, Ocean...

  19. 33 CFR 165.552 - Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; Oyster Creek Generation Station, Forked River, Ocean County, New Jersey. 165.552 Section 165.552 Navigation and Navigable... Coast Guard District § 165.552 Security Zone; Oyster Creek Generation Station, Forked River, Ocean...

  20. Summary of records of surface waters at base stations in Colorado River Basin, 1891-1938

    USGS Publications Warehouse

    Dickinson, W.E.

    1944-01-01

    Collection by the Geological Survey of records of stream flow in the Colorado River Basin was begun in August 1889, when three gaging stations were established in Arizona, on' the Gila, Salt, and Verde Rivers. In 1894-95 the work was extended to include 15 gaging stations, on tributary streams at points in the basin where irrigation development was most intensive, and by 1910 the number had increased to 109. In 1938 there were 262 gaging stations, located to advantage throughout the basin. The earliest known records of discharge in the Colorado River Basin were individual measurements of the main river, made by engineers of the United States Army, 1 at Stone's Ferry near Boulder Canyon August 12, 1875, at Camp Mohave September 2, 1875, and at Fort Yuma March 20, 1876. In the summer of 1876, the Southern Pacific Co. established a gage near the railroad bridge over Colorado River at Yuma, and daily gage readings at that point, now available, are continuous since January 1, 1878.Modern irrigation, using surface waters diverted from various streams in the basin, was begun many years before the first continuous records of discharge Had been obtained. As developments for irrigation and other purposes increased in size and number, became more systematized, and required greater knowledge of water supply, the collection of records of stream flow was substantially augmented through the assistance of many interested parties and agencies, both private and public.

  1. ALARA Overview System at Crystal River Unit 3 Nuclear Station.

    PubMed

    Kline, K B; Cope, W B

    1995-08-01

    During the Spring of 1994 the Health Physics Department at Florida Power Company used video and audio equipment to support remote health physics coverage for their Crystal River Unit 3 refueling outage (Refuel 9). The system consisted of eight cameras with audio interface linked to a control center located in a low-dose area. The system allowed health physics personnel to monitor steam generator and refueling activities with minimum exposure in high-dose areas, cutting by half the dose from the previous outage. B&W Nuclear Technologies provided complete setup, maintenance and tear-down, as well as assuming responsibilities for contaminated video and audio equipment.

  2. Magnetic fingerprint of the sediment load in a meander bend section of the Seine River (France)

    NASA Astrophysics Data System (ADS)

    Kayvantash, D.; Cojan, I.; Kissel, C.; Franke, C.

    2017-06-01

    This study aims to evaluate the potential of magnetic methods to determine the composition of the sediment load in a cross section of an unmanaged meander in the upstream stretch of the Seine River (Marnay-sur-Seine). Suspended particulate matter (SPM) was collected based on a regular sampling scheme along a cross section of the river, at two different depth levels: during a low-water stage (May 2014) and a high-water stage (February 2015). Riverbed sediments (RBS) were collected during the low-water stage and supplementary samples were taken from the outer and inner banks. Magnetic properties of the dry bulk SPM and sieved RBS and bank sediments were analysed. After characterizing the main magnetic carrier as magnetite, hysteresis parameters were measured, giving access to the grain size and the concentration of these magnetite particles. The results combined with sedimentary grain size data were compared to the three-dimensional velocity profile of the river flow. In the RBS where the magnetic grain size is rather uniform, the concentration of magnetite is inversely proportional to the mean grain size of the total sediment indicating that magnetite is strongly associated with the fine sedimentary fraction. The same pattern is observed in the samples from the outer and inner banks. During the low-water stage, the uniformly fine SPM grain size distribution characterizes the wash load. The magnetic fraction is also relatively fine (within the pseudo single domain range) with concentration similar to that of the fine RBS fraction. During the high-water stage, SPM samples correspond to mixtures of wash load and resuspended sediment from the bedload and riverbanks. Here, the grain size distribution is heterogeneous across the section showing coarser particles compared to those in the low-water stage and more varying magnetite concentrations while the magnetic grain size is like that of the low-water stage. The magnetite concentration in the high-water SPM can be

  3. Field Bending Tests of Three Riparian Species Common to the Central Platte River: Resistance, Rigidity and Plant Streamlining

    NASA Astrophysics Data System (ADS)

    Thomas, R. E.; Bankhead, N. L.; Simon, A.

    2010-12-01

    The braided Platte River, central Nebraska, was described by the 19th Century wit Artemus Ward as being “a mile wide and an inch deep”. 150 years on, the upstream diversion and storage of water for agricultural, municipal and industrial uses has caused significant alteration of the hydrologic regime. As a result, sandbars have been progressively colonized by vegetation, leading to the formation of semi-permanent islands and the narrowing of braids by 30-90%. In response, a program was initiated early in 2007 to recreate habitat for endangered birds. One potential management strategy is to modify the hydrologic regime with the goal of removing vegetation and hence re-establishing a dynamic braided channel. An interdisciplinary approach has been adopted to evaluate the likelihood for successful implementation of such a strategy. In a companion paper, Bankhead et al. describe field tests conducted to quantify the forces necessary to uproot and/or break the stems and roots of four common riparian species. Herein, we describe field measurements of the behavior of reed canary grass, phragmites australis and cottonwood plants in response to being pulled horizontally at a known height above the ground. During the tests, the extent of plant bending in response to the applied force and the resistance to bending were monitored continuously. Furthermore, a novel approach employing time lapse photography and image processing was used to quantify associated changes in plant projected area. The mean stem diameter of reed canary grass plants was 3.21 ± 1.08 mm (μ ± σ, n = 69), that of phragmites australis plants was 6.05 ± 1.95 mm (n = 90), and that of cottonwood plants was 4.18 ± 3.59 mm (n = 76). The mean stem length of reed canary grass was 0.77 ± 0.35 m (n = 69), that of phragmites australis was 0.86 ± 0.64 m (n = 90), and that of cottonwoods was 0.55 ± 0.43 m (n = 76). The flexural rigidities (J) of cottonwoods were particularly sensitive to plant age: for 1 year

  4. Flow structure and channel morphodynamics of meander bend chute cutoffs: A case study of the Wabash River, USA

    NASA Astrophysics Data System (ADS)

    Zinger, Jessica A.; Rhoads, Bruce L.; Best, James L.; Johnson, Kevin K.

    2013-12-01

    paper documents the three-dimensional structure of flow and bed morphology of two developing chute cutoffs on a single meander bend on the lower Wabash River, USA, and relates the flow structure to patterns of morphologic change in the evolving cutoff channels. The upstream end of the cutoff channels is characterized by: (1) a zone of flow velocity reduction/stagnation and bar development in the main channel across from the cutoff entrance, (2) flow separation and bar development along the inner (left) bank of the cutoff channel immediately downstream from the cutoff entrance, and (3) helical motion and outward advection of flow momentum entering the cutoff channel, leading to erosion of the outer (right) bank of the cutoff channel. At the downstream end of the cutoff channels, the major hydrodynamic and morphologic features are: (1) flow stagnation along the bank of the main channel immediately upstream of the cutoff channel mouth, (2) convergence of flows from the cutoff and main channels, (3) helical motion of flow from the cutoff, (4) a zone of reduced velocity along the bank of the main channel immediately downstream from the cutoff channel mouth, and (5) development of a prominent bar complex that penetrates into the main channel and extends from the stagnation zone upstream to downstream of the cutoff mouth. These results provide the basis for a conceptual model of chute-cutoff dynamics in which the upstream and downstream ends of a cutoff channel are treated as a bifurcation and confluence, respectively.

  5. Characteristics of suspended and streambed sediment within constructed chutes and the main channel at Upper Hamburg and Glovers Point Bends, Missouri River, Nebraska, 2008

    USGS Publications Warehouse

    Woodward, Brenda K.; Rus, David L.

    2011-01-01

    The U.S. Army Corps of Engineers, Omaha District, as part of the Missouri River Bank Stabilization and Navigation Mitigation Project, has constructed 17 off-channel chutes along the channelized Missouri River, downstream from Sioux City, Iowa, to increase habitat diversity. To better understand characteristics of suspended and streambed sediment within these constructed chutes, the U.S. Geological Survey investigated specific aspects of chute design and function in relation to sediment characteristics including: (1) effects of inlet structures; (2) changes occurring between the inlet and the outlet of a chute; (3) effects of chutes on sediment characteristics in the main channel; and (4) differences in chute dynamics between sampled chutes. Two chutes differing in design, location, and dynamics were studied, Upper Hamburg Bend near Nebraska City, Nebr., and Glovers Point Bend near Winnebago, Nebr. Each site was characterized using five or more sampling transects (two in the chute and three to four in the main channel) designed to bracket sediment exchanges between chutes and the main channel. A sixth transect was included at the Upper Hamburg Bend study site to account for the effects of a nontarget chute having its inlet midway between the inlet and outlet of the primary chute. Representative samples of suspended and streambed sediment were collected at each transect, along with measurements of turbidity and streamflow, between June and November 2008. Four sets of samples were collected at the Glovers Point Bend study site and five sample sets were collected from the Upper Hamburg Bend study site. Results from paired t-tests and standard t-tests indicated that the inlet structure design, passing inflow only from the top of the main-channel water column, reduced the supply of coarse-grained suspended sediment entering the chutes. Statistical comparisons did not indicate differences between the inlet and outlet of either chute; however, anecdotal evidence of recent

  6. NOx reduction through combustion optimization at PEPCO`s Potomac River Station

    SciTech Connect

    Cramer, D.S.; Williams, S.E.; Watkins, J.T.

    1995-06-01

    This paper describes the work done under EPRI Project RP 3383 at Potomac River Station to reduce NOx emissions by adjusting boiler controls. it details the method followed by PEPCO and Lehigh engineers to achieve a 35% reduction in average NOx emissions over a one-month extended test. Parameters that had the largest effect on NOx are discussed. A description of instruments installed to better monitor and control combustion is included.

  7. Bacteriological and Physicochemical Studies on Tigris River Near the Water Purification Stations within Baghdad Province

    PubMed Central

    Al-Bayatti, Khalid K.; Al-Arajy, Kadhum H.; Al-Nuaemy, Seba Hussain

    2012-01-01

    We studied the physical, chemical, and microbiological factors that influence drinking water quality processed from River Tigris, and of the three main drinking water purification stations located at different parts of Tigris River, along with evaluation of drinking water of Al-Shula region in Baghdad city. Water samples were taken monthly from December 2009 to September 2010. Physical and chemical analyses of water included determination of temperature, pH, turbidity, electrical conductivity, total dissolved solids, salinity, dissolved oxygen, and biological oxygen demand. The results of water before and after purification indicated values within the international allowable levels. Microbial analyses included estimation of the number of total viable microbial counts, total coliform, total fecal E. coli and Pseudomonas aeruginosa, and other pathogenic bacteria that might be present in the water of the three stations and of the Tigris River, and also the tap water from Al-Shula houses. The results indicated that the types and proportions of various bacterial species isolated from different water sources were almost similar. This indicates inefficient purification procedures in all the stations studied, which exceeded the internationally allowable level of pathogens in potable water. Also, this explains the high incidence rate of children diarrheal reported in Al-Shula region. PMID:23365587

  8. Bacteriological and physicochemical studies on Tigris River near the water purification stations within Baghdad Province.

    PubMed

    Al-Bayatti, Khalid K; Al-Arajy, Kadhum H; Al-Nuaemy, Seba Hussain

    2012-01-01

    We studied the physical, chemical, and microbiological factors that influence drinking water quality processed from River Tigris, and of the three main drinking water purification stations located at different parts of Tigris River, along with evaluation of drinking water of Al-Shula region in Baghdad city. Water samples were taken monthly from December 2009 to September 2010. Physical and chemical analyses of water included determination of temperature, pH, turbidity, electrical conductivity, total dissolved solids, salinity, dissolved oxygen, and biological oxygen demand. The results of water before and after purification indicated values within the international allowable levels. Microbial analyses included estimation of the number of total viable microbial counts, total coliform, total fecal E. coli and Pseudomonas aeruginosa, and other pathogenic bacteria that might be present in the water of the three stations and of the Tigris River, and also the tap water from Al-Shula houses. The results indicated that the types and proportions of various bacterial species isolated from different water sources were almost similar. This indicates inefficient purification procedures in all the stations studied, which exceeded the internationally allowable level of pathogens in potable water. Also, this explains the high incidence rate of children diarrheal reported in Al-Shula region.

  9. 33 CFR 334.285 - York River and the Naval Weapons Station Yorktown-Cheatham Annex, Yorktown, Virginia; danger zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false York River and the Naval Weapons... RESTRICTED AREA REGULATIONS § 334.285 York River and the Naval Weapons Station Yorktown-Cheatham Annex... less than the maximum range of the weapons being used at the facility or while a vessel is within the...

  10. 78 FR 57323 - York River and the Naval Weapons Station Yorktown-Cheatham Annex, Yorktown, Virginia; Danger Zone

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-18

    ... Department of the Army, Corps of Engineers 33 CFR Part 334 York River and the Naval Weapons Station Yorktown... and the Naval Weapons Station Yorktown- Cheatham Annex, Yorktown, Virginia; danger zone. (a) The area... firing activities shall be conducted when the visibility is less that the maximum range of the...

  11. 33 CFR 334.155 - Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. 334.155 Section 334.155 Navigation and... RESTRICTED AREA REGULATIONS § 334.155 Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. (a) The area. The waters within the Naval Station Annapolis small boat basin and...

  12. 33 CFR 334.155 - Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. 334.155 Section 334.155 Navigation and... RESTRICTED AREA REGULATIONS § 334.155 Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. (a) The area. The waters within the Naval Station Annapolis small boat basin and...

  13. 33 CFR 334.155 - Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. 334.155 Section 334.155 Navigation and... RESTRICTED AREA REGULATIONS § 334.155 Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. (a) The area. The waters within the Naval Station Annapolis small boat basin and...

  14. 33 CFR 334.155 - Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. 334.155 Section 334.155 Navigation and... RESTRICTED AREA REGULATIONS § 334.155 Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. (a) The area. The waters within the Naval Station Annapolis small boat basin and...

  15. 33 CFR 334.155 - Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. 334.155 Section 334.155 Navigation and... RESTRICTED AREA REGULATIONS § 334.155 Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. (a) The area. The waters within the Naval Station Annapolis small boat basin and...

  16. Two-station comparison of peak flows to improve flood-frequency estimates for seven streamflow-gaging stations in the Salmon and Clearwater River Basins, Central Idaho

    USGS Publications Warehouse

    Berenbrock, Charles

    2003-01-01

    Improved flood-frequency estimates for short-term (10 or fewer years of record) streamflow-gaging stations were needed to support instream flow studies by the U.S. Forest Service, which are focused on quantifying water rights necessary to maintain or restore productive fish habitat. Because peak-flow data for short-term gaging stations can be biased by having been collected during an unusually wet, dry, or otherwise unrepresentative period of record, the data may not represent the full range of potential floods at a site. To test whether peak-flow estimates for short-term gaging stations could be improved, the two-station comparison method was used to adjust the logarithmic mean and logarithmic standard deviation of peak flows for seven short-term gaging stations in the Salmon and Clearwater River Basins, central Idaho. Correlation coefficients determined from regression of peak flows for paired short-term and long-term (more than 10 years of record) gaging stations over a concurrent period of record indicated that the mean and standard deviation of peak flows for all short-term gaging stations would be improved. Flood-frequency estimates for seven short-term gaging stations were determined using the adjusted mean and standard deviation. The original (unadjusted) flood-frequency estimates for three of the seven short-term gaging stations differed from the adjusted estimates by less than 10 percent, probably because the data were collected during periods representing the full range of peak flows. Unadjusted flood-frequency estimates for four short-term gaging stations differed from the adjusted estimates by more than 10 percent; unadjusted estimates for Little Slate Creek and Salmon River near Obsidian differed from adjusted estimates by nearly 30 percent. These large differences probably are attributable to unrepresentative periods of peak-flow data collection.

  17. Benthic community of the Savannah River below a peaking hydropower station

    USGS Publications Warehouse

    Hudson, Patrick L.; Nichols, S. Jerrine

    1986-01-01

    The Savannah River below Hartwell Dam, on the South Carolina-Georgia border, contains at least 206 benthic invertebrate taxa, even though this tailwater undergoes substantial daily fluctuations in water flow, temperature, and dissolved oxygen. Oligochaetes, chironomids, and amphipods dominate the community immediately below the dam. Farther downstream, larger organisms (i.e., Ephemeroptera, Trichoptera, etc.) dominate the benthic community. The high diversity of this system is primarily attributed to the intensive effort we expended to identify invertebrates to species level. We conclude that tailwaters associated with peaking hydropower stations may in fact have the diverse community assemblages found in natural streams and that this has not been recognized by other investigators because the bulk of the fauna is made up of small forms that are easily overlooked. Comparisons of tailwater fauna communities with those in control areas should be limited to rivers of similar size.

  18. Flood hazard assessment of the Hoh River at Olympic National Park ranger station, Washington

    USGS Publications Warehouse

    Kresch, D.L.; Pierson, T.C.

    1987-01-01

    Federal regulations require buildings and public facilities on Federal land to be located beyond or protected from inundation by a 100-year flood. Flood elevations, velocities and boundaries were determined for the occurrence of a 100-year flood through a reach, approximately 1-mi-long, of the Hoh River at the ranger station complex in Olympic National Park. Flood elevations, estimated by step-backwater analysis of the 100-year flood discharge through 14 channel and flood-plain cross sections of the Hoh River, indicate that the extent of flooding in the vicinity of buildings or public facilities at the ranger station complex is likely to be limited mostly to two historic meander channels that lie partly within loop A of the public campground and that average flood depths of about 2 feet or less would be anticipated in these channels. Mean flow velocities at the cross sections, corresponding to the passage of a 100-year flood, ranged from about 5 to over 11 ft/sec. Flooding in the vicinity of either the visitors center or the residential and maintenance areas is unlikely unless the small earthen dam at the upstream end of Taft Creek were to fail. Debris flows with volumes on the order of 100 to 1,000 cu yards could be expected to occur in the small creeks that drain the steep valley wall north of the ranger station complex. Historic debris flows in these creeks have generally traveled no more than about 100 yards out onto the valley floor. The potential risk that future debris flows in these creeks might reach developed areas within the ranger station complex is considered to be small because most of the developed areas within the complex are situated more than 100 yards from the base of the valley wall. Landslides or rock avalanches originating from the north valley wall with volumes potentially much larger than those for debris flows could have a significant impact on the ranger station complex. The probability that such landslides or avalanches may occur is

  19. Uncertainty in low-flow data from three streamflow-gaging stations on the upper Verde River, Arizona

    USGS Publications Warehouse

    Anning, D.W.; ,

    2004-01-01

    The evaluation of uncertainty in low-flow data collected from three streamflow-gaging stations on the upper Verde River, Arizona, was presented. In downstream order, the stations are Verde River near Paulden, Verde River near Clarkdale, and Verde River near Camp Verde. A monitoring objective of the evaluation was to characterize discharge of the lower flow regime through a variety of procedures such as frequency analysis and base-flow analysis. For Verde River near Paulden and near Camp Verde, the uncertainty of daily low flows can be reduced by decreasing the uncertainty of discharge-measurement frequency, or building an artificial control that would have a stable stage-discharge relation over time.

  20. Intercomparison study of atmospheric methane and carbon dioxide concentrations measured at the Ebre River Delta Station

    NASA Astrophysics Data System (ADS)

    Occhipinti, Paola; Morguí, Josep Anton; Àgueda, Alba; Batet, Oscar; Borràs, Sílvia; Cañas, Lídia; Curcoll, Roger; Grossi, Claudia; Nofuentes, Manel; Vazquez, Eusebi; Rodó, Xavier

    2015-04-01

    In the framework of the ClimaDat project, IC3 has established a network of eight monitoring stations across the Iberian Peninsula and the Canarian Archipelago with the aim of studying climate processes. The monitoring station at the Ebre River Delta (DEC3) is located in the Ebre River Delta Natural Park (40° 44' N; 0° 47' E) and it is characterized by the typical North-Western Mediterranean climate. Since 2013, atmospheric greenhouse gases (GHG) and 222Rn tracer gas together with the meteorological parameters are continuously measured from a 10 m a.g.l. height tower. Atmospheric GHG (CO2, CH4, CO and N2O) concentrations are determined using a Picarro analyzer G2301 (CO2 and CH4) and a modified gas chromatograph (GC) Agilent 6890N (CO2, CH4, CO and N2O). Open data access is available from the www.climadat.es website. Data collected at the DEC3 station are also submitted to the InGOS platform since this station is part of the InGOS European infrastructure project. Researchers from the Laboratory of the Atmosphere and the Oceans (LAO) at IC3 have performed an intercomparison study at the DEC3 site between three different Picarro analyzers (two Picarro G2301 and one Picarro G2301M), a Los Gatos Research (LGR) analyzer and the GC system already installed at the station. The aim of this study is to compare and assess the measuring agreement between the four optical gas analyzers and the GC. In the first part of the experiment, all instruments have been calibrated using NOAA gases as primary standards analyzing five Praxair provided targets to evaluate the precision of the measuring instruments. Max Plank Institute (MPI) gases have been used as secondary standards for the GC whereas Praxair provided tanks are used as secondary standards for the Picarro and the LGR analyzers. In the second part of the experiment, atmospheric GHG were measured from natural atmospheric air taken from a 10 m a.g.l. inlet. Daily cycles of GHG measurements were carried out using different

  1. Spatial pattern assessment of river water quality: implications of reducing the number of monitoring stations and chemical parameters.

    PubMed

    Wang, Yeuh-Bin; Liu, Chen-Wuing; Liao, Pei-Yu; Lee, Jin-Jing

    2014-03-01

    The Tamsui River basin is located in Northern Taiwan and encompasses the most metropolitan city in Taiwan, Taipei City. The Taiwan Environmental Protection Administration (EPA) has established 38 water quality monitoring stations in the Tamsui River basin and performed regular river water quality monitoring for the past two decades. Because of the limited budget of the Taiwan EPA, adjusting the monitoring program while maintaining water quality data is critical. Multivariate analysis methods, such as cluster analysis (CA), factor analysis (FA), and discriminate analysis (DA), are useful tools for the statistically spatial assessment of surface water quality. This study integrated CA, FA, and DA to evaluate the spatial variance of water quality in the metropolitan city of Taipei. Performing CA involved categorizing monitoring stations into three groups: high-, moderate-, and low-pollution areas. In addition, this categorization of monitoring stations was in agreement with that of the assessment that involved using the simple river pollution index. Four latent factors that predominantly influence the river water quality of the Tamsui River basin are assessed using FA: anthropogenic pollution, the nitrification process, seawater intrusion, and geological and weathering processes. We plotted a spatial pattern using the four latent factor scores and identified ten redundant monitoring stations near each upstream station with the same score pattern. We extracted five significant parameters by using DA: total organic carbon, total phosphorus, As, Cu, and nitrate, with spatial variance to differentiate them from the polluted condition of the group obtained by using CA. Finally, this study suggests that the Taiwan EPA can adjust the surface water-monitoring program of the Tamsui River by reducing the monitoring stations to 28 and the measured chemical parameters to five to lower monitoring costs.

  2. A novel permanent gauge-cam station for surface-flow observations on the Tiber River

    NASA Astrophysics Data System (ADS)

    Tauro, Flavia; Petroselli, Andrea; Porfiri, Maurizio; Giandomenico, Lorenzo; Bernardi, Guido; Mele, Francesco; Spina, Domenico; Grimaldi, Salvatore

    2016-06-01

    Flow monitoring of riverine environments is crucial for hydrology and hydraulic engineering practice. Besides few experimental implementations, flow gauging relies on local water level and surface-flow velocity measurements through ultrasonic meters and radars. In this paper, we describe a novel permanent gauge-cam station for large-scale and continuous observation of surface flows, based on remote acquisition and calibration of video data. Located on the Tiber River, in the center of Rome, Italy, the station captures 1 min videos every 10 min over an area oriented along the river cross section of up to 20.6 × 15.5 m2. In a feasibility study, we demonstrate that accurate surface-flow velocity estimations can be obtained by analyzing experimental images via particle tracking velocimetry (PTV). In medium illumination conditions (70-75 lux), PTV leads to velocity estimations in close agreement with radar records and is less affected by uneven lighting than large-scale particle image velocimetry. Future efforts will be devoted to the development of a comprehensive test bed infrastructure for investigating the potential of multiple optics-based approaches for surface hydrology.

  3. Numerical modeling of erosional and depositional bank processes in migrating river bends with self-formed width: Morphodynamics of bar push and bank pull

    NASA Astrophysics Data System (ADS)

    Eke, Esther; Parker, Gary; Shimizu, Yasuyuki

    2014-07-01

    Meandering rivers display active communication between bank erosion and bar deposition processes. How does this occur? How does the river select its width? To answer these questions, we implement a model for meander migration where both bank processes (erosion and deposition) are considered independently. Bank erosion is modeled as erosion of purely noncohesive bank material damped by natural slump block armoring; channel deposition is modeled via flow-retarded vegetal encroachment. Both processes are tied to a slope-dependent channel forming Shields number; banks with near-bank Shields number below this value undergo deposition, and those above it undergo erosion. Channel-forming Shields number must increase with slope, as dictated by available data and model performance. Straight channel modeling shows that a channel arrives at an equilibrium width from any initial condition. For the channel bend, the river always approaches an asymptotic state where width reduces slowly in time and where bank erosion and deposition occur at nearly equal rates. Before this state is reached, however, the river follows a phase-plane trajectory with four possible regimes: (a) both banks erode, (b) both banks deposit, (c) both banks migrate outward, but with a faster depositing bank (bar push), and (d) both banks migrate outward, but with a faster eroding bank (bank pull). The trajectory of migration on the phase plane depends on initial conditions and input parameters controlling the rate of depositional and erosional migration. All input parameters have specific physical meaning, and the potential to be measured in the field.

  4. Surface flow observations from a gauge-cam station on the Tiber river

    NASA Astrophysics Data System (ADS)

    Tauro, Flavia; Porfiri, Maurizio; Petroselli, Andrea; Grimaldi, Salvatore

    2016-04-01

    Understanding the kinematic organization of natural water bodies is central to hydrology and environmental engineering practice. Reliable and continuous flow observations are essential to comprehend flood generation and propagation mechanisms, erosion dynamics, sediment transport, and drainage network evolution. In engineering practice, flood warning systems largely rely on real-time discharge measurements, and flow velocity monitoring is important for the design and management of hydraulic structures, such as reservoirs and hydropower plants. Traditionally, gauging stations have been equipped with water level meters, and stage-discharge relationships (rating curves) have been established through few direct discharge measurements. Only in rare instances, monitoring stations have integrated radar technology for local measurement of surface flow velocity. Establishing accurate rating curves depends on the availability of a comprehensive range of discharge values, including measurements recorded during extreme events. However, discharge values during high-flow events are often difficult or even impossible to obtain, thereby hampering the reliability of discharge predictions. Fully remote observations have been enabled in the past ten years through optics-based velocimetry techniques. Such methodologies enable the estimation of the surface flow velocity field over extended regions from the motion of naturally occurring debris or floaters dragged by the current. Resting on the potential demonstrated by such approaches, here, we present a novel permanent gauge-cam station for the observation of the flow velocity field in the Tiber river. This new station captures one-minute videos every 10 minutes over an area of up to 20.6 × 15.5m2. In a feasibility study, we demonstrate that experimental images analyzed via particle tracking velocimetry and particle image velocimetry can be used to obtain accurate surface flow velocity estimations in close agreement with radar records

  5. Delivery of water from Belton Reservoir to the Brazos River gaging station at Richmond, Texas, by way of the Leon, Little, and Brazos River channels, 1956

    USGS Publications Warehouse

    Havelka, D.E.; Parten, E.M.

    1957-01-01

    Beginning November 1, 1956 and ending December 14, 1956, the Corps of Engineers, in cooperation with the Brazos River Authority released 73,000 acre-feet of water (as measured at the gaging station on Leon river near Belton) from the Belton Reservoir for industrial use in the vicinity of Freeport, Tex. (see fig. 1). The need for this water at Freeport came as a result of the prolonged drought conditions causing flows in the Brazos River in the vicinity of Freeport to be insufficient to satisfy the industrial and other uses of vital importance.

  6. Discharge Estimation Using Satellite Gravity During Flood Seasons at the Óbidos Gauge Station, Amazon River

    NASA Astrophysics Data System (ADS)

    Eom, J.; Seo, K. W.; Lee, Y. K.

    2014-12-01

    Reliable measurement of river discharge is important for management of water resource and understanding of hydrological cycles particularly associated with global and regional climate changes. Practically, to obtain continuous time series of river discharge, regression analysis of an empirical relationship between accumulated water level and discharge data is used. During wet season, however, the relationship includes more uncertainty due to the difficulty of accurate discharge measurement. This is particularly true for the Amazon River because significant amount of water flows outside river channel during flooding. For an alternative way to estimate river discharge, we use GRACE time-varying gravity measurement from January 2003 to December 2012. We first apply Empirical Orthogonal Function (EOF) for GRACE time-varying gravity fields in Amazon and successfully isolate gravity signal in the main stream. The EOF time series represents relative river discharge variations without larger uncertainty during flooding season compared to conventional in-situ discharge estimate. Estimates of Amazon River discharge based on GRACE data are very close to those from observed at gauge stations during dry seasons. However, our estimates are larger than in-situ data in high water seasons, and the difference is the maximum at the 2009 flooding. This is probably because in-situ observation underestimates river discharge during wet season due possibly to detoured water in river pathway developed during flooding while GRACE observes integrated water mass variations in river channels.

  7. Output improvement of Sg. Piah run-off river hydro-electric station with a new computed river flow-based control system

    NASA Astrophysics Data System (ADS)

    Jidin, Razali; Othman, Bahari

    2013-06-01

    The lower Sg. Piah hydro-electric station is a river run-off hydro scheme with generators capable of generating 55MW of electricity. It is located 30km away from Sg. Siput, a small town in the state of Perak, Malaysia. The station has two turbines (Pelton) to harness energy from water that flow through a 7km tunnel from a small intake dam. The trait of a run-off river hydro station is small-reservoir that cannot store water for a long duration; therefore potential energy carried by the spillage will be wasted if the dam level is not appropriately regulated. To improve the station annual energy output, a new controller based on the computed river flow has been installed. The controller regulates the dam level with an algorithm based on the river flow derived indirectly from the intake-dam water level and other plant parameters. The controller has been able to maintain the dam at optimum water level and regulate the turbines to maximize the total generation output.

  8. Transport of suspended and bedload sediment at eight stations in the Coeur d'Alene River basin, Idaho

    USGS Publications Warehouse

    Clark, Greg M.; Woods, Paul F.

    2000-01-01

    At most of the stations, and at the stream discharges sampled, the bedload was primarily composed of material greater than 2 millimeters in diameter, the break between sand and gravel. A predominance of sand-sized bedload was noted at only a few stations, and generally only during low stream discharge. The particle-size distribution of bedload sediment at most stations became proportionately coarser as stream discharge increased. During the peak of snowmelt runoff for water years 1999 and 2000, gravel-sized material between 2 and 64 millimeters in diameter comprised more than 70 percent of the bedload transport at most stations. However, at the station on the Coeur d’Alene River at Rose Lake, the bedload was predominantly composed of fine-grained material of less than 1 millimeter in diameter for all measured stream discharges. The slow water velocities at Rose Lake accounted for the predominance of fine-grained sediment transport.

  9. 33 CFR 165.553 - Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey. 165.553 Section 165.553 Navigation... Limited Access Areas Fifth Coast Guard District § 165.553 Security Zone; Salem and Hope Creek Generation...

  10. 33 CFR 165.553 - Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey. 165.553 Section 165.553 Navigation... Limited Access Areas Fifth Coast Guard District § 165.553 Security Zone; Salem and Hope Creek Generation...

  11. 33 CFR 165.553 - Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey. 165.553 Section 165.553 Navigation... Limited Access Areas Fifth Coast Guard District § 165.553 Security Zone; Salem and Hope Creek Generation...

  12. 33 CFR 165.553 - Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey. 165.553 Section 165.553 Navigation... Limited Access Areas Fifth Coast Guard District § 165.553 Security Zone; Salem and Hope Creek Generation...

  13. 33 CFR 165.553 - Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; Salem and Hope Creek Generation Stations, Delaware River, Salem County, New Jersey. 165.553 Section 165.553 Navigation... Limited Access Areas Fifth Coast Guard District § 165.553 Security Zone; Salem and Hope Creek Generation...

  14. Flow Estimate of Carbon Dioxide in a Amazon River Hydrological Station

    NASA Astrophysics Data System (ADS)

    Moura, J. M. S.; Ferreira, R. B., Jr.; Tapajós, R. P.

    2014-12-01

    Recent measurements in the Amazon suggest that the flow of CO2 in surface waters may reach the order of 1GT per year and isotopic analyzes suggest that this carbon is a direct result of organic matter degradation (OMD) in rivers and the measured concentration exceeds the value expected for there to be equilibrium with the atmosphere (Richey et al, 2002). This study aimed to measure and check the seasonal variability of CO2 fluxes in a range of six months (September 2013-February 2014) in the Strait Óbidos hydrological station located geographically in the coordinates 55 ° 1 '4 "S and 55 ° 31' 4" W. In addiction, it is intended to correlate the data with physical-chemical water parameters pH, dissolved oxygen (DO), and temperature and humidity. The method used for the measurement of CO2 concentration in the atmosphere-water interface is the floating chamber liked with an infrared gas analyzer (IRGA- Infrared Gas Analyzer). The physical-chemical parameters of water were measured using a multiparameter probe YSI Professional Plus model. The preliminary results shows values average CO2 flux was approximately 15.65 1,01ppm / m2s-1 for the months of September and October and between the months of November, 2013 and February 2014 the CO2 flux average was 4.40 + 1.94 ppm / m2s-1. In addiction to the high temperature in dry season, in the water column there is sufficient convection for the existence of gases transport from water to atmosphere, resulting in increase of exchange. Thus, the decreased amount of radiation and consequently the low temperatures in the humid period (on average 27.2 ° C) should affect the OMD in the river, responsible for the production of dissolved CO2. Keywords: CO2 flux, seasonal variability, amazon river

  15. Holocene sedimentation and coastal wetlands response to rising sea level at the Aucilla river mouth, a low energy coast in the Big Bend area of Florida

    USGS Publications Warehouse

    Garrett, Connie; Hertler, Heidi; Hoenstine, Ronald; Highley, Brad

    1993-01-01

    The shallow dip of the Florida carbonate platform results in low wave energy on Florida ???Big Bend??? coasts. Therefore sedimentation is dominated by river-and tidal-hydrodynamics near the Aucilla River mouth. Where present, Holocene sediments are thin and unconformably overlie Oligocene-aged Suwannee Limestone. The oldest unlithified sediments include reworked carbonate rubble with clay and wood fragments (seven thousand years old or less, based on wood radio-carbon dating). Although this basal sequence is observed in most areas, the sediments that overlie it vary. Sediment sequences from the outer littoral to submarine environments include organic-rich sands, oyster biotherm remains, and cleaner sands with organic-filled burrows. Inner littoral (salt-marsh) sequences generally consist of sandy, fining-upwards sequences in which dry weights of fine-grained clastics and organic components increase up-sequence at similar rates. Offshore sediments preserve greatly attenuated fluvial and salt-marsh facies, if these facies are preserved at all. With sea-level rise, erosion can result from insufficient sediment supply and down-cutting by tidal currents (Dolotov, 1992; and Dalrymple et al., 1992). Dolotov (1992) attributes displacement of original coastal stratigraphy to insufficient sediments for beach profile maintenance, while Dalrymple et al. (1992) attribute erosional truncation (ravinement) or complete removal of portions of typical estuarine sequences to headward migration of tidal channels.

  16. Cultural Resources Survey of Greenwood Bend and Iowa Point Revetment, Mississippi River M-293.1 to 280-L

    DTIC Science & Technology

    1993-10-01

    temnmincki rivers and lakes three-toed box turtle Terrapene carolina terrestrial , wooded areas or edges triunguis_ ground skink Leiolopisma laterale...flaWgaster eastern garter snake 7hamnophis sinalis sinails virtually all se-miaquatic to terrestrial habitats speckled king snake Lampropekts getuda... Tapirus copei), and extinct tapir ( Tapirus veroensis). (Brown 1938, Steere 1938, Richards 1938, Domning 1969, Lowrey 1974, Delcourt and Delcourt 1977

  17. Analysis of current-meter data at Columbia River gaging stations, Washington and Oregon

    USGS Publications Warehouse

    Savini, John; Bodhaine, G.L.

    1971-01-01

    The U.S. Geological Survey developed equipment to measure stream velocity simultaneously with 10 current meters arranged in a vertical and to measure velocity closer to the streambed than attainable with conventional equipment. With the 10 current meters, synchronous velocities were recorded for a period of 66 minutes at 10 different depths in one vertical of one gaging-station cross section. In addition, with a current meter installed on a special bracket to allow measurements to 0.5 foot above streambed, data were obtained at two to four verticals in four gaging-station cross sections. The mean velocity determined for the 66-minute period of record was 3.30 fps (feet per second). The graphic record of velocity was analyzed on a minute-by-minute basis. It was noted that the shape of the vertical velocity curves (plot of horizontal flow velocities measured in a vertical) changed from one minute to the next, but the change seemed to be random. Velocities obtained at different depths in the, profile fluctuated significantly, with the 1-minute velocities obtained at 0.05 depth (5 percent of total depths measured from the surface at indicated vertical) showing the smallest range--0.66 fps--and those at 0.55 depth the largest range--l.22 fps. The standard deviation, expressed in feet per second, of the velocity at each point in the vertical tended to increase with depth--from 0.16 fps at 0.05 depth to a maximum of 0.24 fps at 0.75 depth. The standard deviation, expressed as a percentage of the mean velocity, ranged from about 4 percent near the surface to 11 percent at 0.95 depth. In spite of the fluctuation in mean velocity that occurred during the 66 minutes and observation period of 4 minutes yields a mean velocity that differs from the 66-minute mean by less than one-half of a percent. Determining the mean velocity by averaging the 10-point observations of the 66minute run proved to be as accurate as by plotting the vertical velocity curvy (from the averaged 10

  18. Study on the influence of small hydropower stations on the macroinvertebrates community-Take Nanhe River as a case, China

    NASA Astrophysics Data System (ADS)

    Zhao, Weihua; Li, Qingyun; Guo, Weijie; Wang, Zhenhua

    2017-05-01

    This study take Nahan River as a case to research the impacts of small hydropower stations on macroinvertebrates community. Results showed that a total of 13 macroinvertebrate samples was collected and contained 56 taxa belonging to 18 families and 35 genera. The influence of runoff regulation was more seriously than hydrological period. There were obvious zoning phenomenon of macroinvertebrates between reservoir, downdam reaches and natural reaches. From reservoir, downdam reaches to natural reaches, species abundance increased in turn. There are the least species in reservoir, the most in natural rivers. The reservoirs had the highest biomass and were quite different from those in downdam and natural reaches. However, there was no significant difference between different periods of hydropower station.

  19. Simulations of the Influence of MHK-Turbine Operation on Hydrodynamics and Sediment Transport for Scotlandville Bend, Mississippi River

    NASA Astrophysics Data System (ADS)

    Barco, J.; Johnson, E.; Roberts, J. D.; James, S. C.; Jones, C.

    2012-12-01

    Water-current MHK turbines are receiving growing interest in many parts of the world with hydrokinetic resources. However, little is known about the potential effects of MHK device operation in coastal waters, estuaries, or rivers, or of the cumulative impacts of these devices on aquatic ecosystems over years or decades of operation. This lack of knowledge affects the actions of regulatory agencies, the opinions of stakeholder groups, and the commitment of energy project developers and investors. There is an urgent need for practical, accessible tools and peer-reviewed publications to help industry and regulators evaluate environmental impacts and mitigation measures and to establish best siting and design practices. This study presents a methodology to assess the hydrokinetic potential and its environmental effects in a reach of the Mississippi river. The potential changes to the physical environment imposed by operation of MHK turbine arrays were evaluated using the modeling platform SNL-EFDC. Energy extraction is simulated using momentum sinks recently coded into SNL-EFDC, which is an augmented version of US EPA's Environmental Fluid Dynamics Code (EFDC). Three different scenarios (4-, 23- and 112-piling arrays) were development for SNL-EFDC simulations. The four-piling array included 12 turbines; the 23-piling, 132 turbines; and the 112-piling, 638 turbines. As expected, average velocities decrease downstream of each MHK device due to energy removal and blunt-body form drag from the MHK support structures. Furthermore, the velocity profiles exhibit a wake velocity deficit downstream of the last MHK row, which disappears within about 15 array widths downstream. This mirrors the approximate recovery of the wake for a single MHK turbine in a straight channel, which recovers to a ~10% deficit around 15 device diameters downstream. Changes in the flow field also alter sediment transport dynamics around and downstream of an MHK array. Model results with and without

  20. Dating the incision of the Yangtze River gorge at the First Bend using three-nuclide burial ages

    NASA Astrophysics Data System (ADS)

    McPhillips, Devin; Hoke, Gregory D.; Liu-Zeng, Jing; Bierman, Paul R.; Rood, Dylan H.; Niedermann, Samuel

    2016-01-01

    Incision of the Yangtze River gorge is widely interpreted as evidence for lower crustal flow beneath the southeast margin of the Tibetan Plateau. Previous work focused on the onset of incision, but the duration of incision remains unknown. Here we present cosmogenic nuclide burial ages of sediments collected from caves on the walls of the gorge that show the gorge was incised ~1 km sometime between 18 and 9 Ma. Thereafter, incision slowed substantially. We resolve middle Miocene burial ages by using three nuclides and accounting for in situ muogenic production. This approach explains the absolute concentrations of 10Be, 26Al, and 21Ne, as well as 26Al/10Be and 21Ne/10Be ratios. A declining incision rate challenges existing geodynamic interpretations by suggesting that either (1) surface uplift has ceased immediately south of the plateau margin or (2) gorge incision is not a useful proxy for the timing of surface uplift.

  1. Spatial patterns of groundwater-surface water interactions at the meander-bend scale in a gravel-bed lowland river during a large-scale flow experiment

    NASA Astrophysics Data System (ADS)

    Bray, E. N.; Dunne, T.

    2012-12-01

    Improved characterization of 1) streambed hydraulic conductivity and 2) near-bed and subsurface water temperatures allows better understanding of the spatial patterns of groundwater-surface water exchange in rivers. We measured the effects of a large-scale flow experiment on groundwater-surface water exchange and temperature using fiber optic distributed temperature sensing (DTS), measured temperature in the shallow hyporheic zone (46 cm), and measured streambed saturated hydraulic conductivity (Ksat) over the length of three river meander bends (2 km). Measured channel bed elevation, flow depth, velocity, and bed-material grain size were used to develop a two-dimensional numerical model of the flow field as boundary conditions for a model of the hyporheic flow field. We deployed 2 km of fiber-optic cable directly on top of the riverbed over three pool-riffle sequences each with a different degree of bed mobility. DTS data were collected every 2 m for 32 days (1.5 days at 10 cms, 10 days at 20 cms, 16 days at 10 cms, and 4.5 days at 2-4 cms). Three installations of six hyporheic zone sensors, located near the upstream and downstream ends of the DTS cable, recorded interstitial pore water temperature at depths of 46 cm. During flows of 10 cms, we measured Ksat in the streambed at depths of 60 cm using a groundwater standpipe and backpack permeameter over the length of two meander bends. DTS results showed relatively uniform temperature over the 2-km reach during the initial flow of 10 cms. Near-bed temperatures averaged 15.6°C while pore water temperatures averaged 15.4°C. The 20 cms flow decreased near-bed temperatures to 14.9°C and pore water temperatures averaged 14.7°C. However, during the 20 cms flow, the bed became mobile causing local scour and deposition at three locations and buried the DTS cable with gravel/sand up to 26 cm deep. Our DTS results allowed us to record the transition from near-bed temperatures to shallow subsurface temperatures during a

  2. Decadal flood frequency analyses: Case study of station Litija on the Sava river

    NASA Astrophysics Data System (ADS)

    Bezak, Nejc; Brilly, Mitja; Sraj, Mojca

    2013-04-01

    The objective of the study was (1) to perform decadal flood frequency analyses for the nine 30 years long data series, (2) to compare some commonly used distribution functions, (3) to compare the method of moments and the method of L-moments, and (4) to evaluate changes in the Q-T curves for the different hydrological periods. Decadal flood frequency analyses can be useful in climate changes or climate variability assessment. Investigation of the influence of the selected period for flood frequency analyses is important for the observation of changes in the discharge data. To reach the optimal flood frequency analyses results one should choose the best fitting distribution function and appropriate parameter estimation technique. The hydrological station Litija on the river Sava is one of the oldest gauging stations in Slovenia. 116 years of the daily discharge data were used for decadal flood frequency analyses. Data was separated in nine parts, each part contained 30 years of annual maximums. The normal, log-normal, Pearson 3, log-Pearson 3, Gumbel, generalized extreme value (GEV) and generalized logistic (GL) distributions were used for flood frequency analyses. The method of moments and the method of L-moments were used for parameters estimation. The root mean square error (RMSE), mean absolute error (MAE), Probability plot correlation coefficient (PPCC), Kolmogorov-Smirnov (K-S), Anderson-Darling (A-D) and AIC (Akaike information criterion) tests were used to compare distribution functions and different data samples. The L-moments ratio diagram was also used to assess differences between distribution functions. The GEV, Pearson 3 and log-Pearson 3 distributions gave better results as the normal, log-normal, Gumbel and GL distributions. The Gumbel and log-normal distributions had larger dispersion of tests results as other considered distributions. When distribution parameters were estimated with the method of L-moments test results were better as in case of the

  3. Using NASA's Giovanni System to Simulate Time-Series Stations in the Outflow Region of California's Eel River

    NASA Technical Reports Server (NTRS)

    Acker, James G.; Shen, Suhung; Leptoukh, Gregory G.; Lee, Zhongping

    2012-01-01

    Oceanographic time-series stations provide vital data for the monitoring of oceanic processes, particularly those associated with trends over time and interannual variability. There are likely numerous locations where the establishment of a time-series station would be desirable, but for reasons of funding or logistics, such establishment may not be feasible. An alternative to an operational time-series station is monitoring of sites via remote sensing. In this study, the NASA Giovanni data system is employed to simulate the establishment of two time-series stations near the outflow region of California s Eel River, which carries a high sediment load. Previous time-series analysis of this location (Acker et al. 2009) indicated that remotely-sensed chl a exhibits a statistically significant increasing trend during summer (low flow) months, but no apparent trend during winter (high flow) months. Examination of several newly-available ocean data parameters in Giovanni, including 8-day resolution data, demonstrates the differences in ocean parameter trends at the two locations compared to regionally-averaged time-series. The hypothesis that the increased summer chl a values are related to increasing SST is evaluated, and the signature of the Eel River plume is defined with ocean optical parameters.

  4. Hanford Meteorological Station computer codes: Volume 7, The RIVER computer code

    SciTech Connect

    Andrews, G.L.; Buck, J.W.

    1988-03-01

    The RIVER computer code is used to archive Columbia River data measured at the 100N reactor. The data are recorded every other hour starting at 0100 Pacific Standard Time (12 observations in a day), and consists of river elevation, temperature, and flow rate. The program prompts the user for river data by using a data entry form. After the data have been enetered and verified, the program appends each hour of river data to the end of each corresponding surface observation record for the current day. The appended data are then stored in the current month's surface observation file.

  5. Comparative swimming and station-holding ability of the threatened Rocky Mountain Sculpin (Cottus sp.) from four hydrologically distinct rivers

    PubMed Central

    Veillard, Marie F.; Ruppert, Jonathan L.W.; Tierney, Keith; Watkinson, Douglas A.

    2017-01-01

    Abstract Hydrologic alterations, such as dams, culverts or diversions, can introduce new selection pressures on freshwater fishes, where they are required to adapt to novel environmental conditions. Our study investigated how species adapt to natural and altered stream flow, where we use the threatened Rocky Mountain Sculpin (Cottus sp.) as a model organism. We compared the swimming and station-holding performance of Rocky Mountain Sculpin from four different hydrologic regimes in Alberta and British Columbia, including the North Milk River, a system that experiences increased flows from a large-scale diversion. We measured the slip (Uslip) and failure (Uburst) velocities over three constant acceleration test trials. Uslip was defined as the point at which individuals required the addition of bursting or swimming to maintain position. Uburst was defined as the point at which individuals were unable to hold position in the swimming chamber through swimming, bursting or holding techniques without fully or partially resting on the electrified back plate. We found individuals from the Flathead River in British Columbia (with the highest natural flow) failed at significantly higher Uburst velocities than fish from the southern Albertan populations. However, there was no relationship between peak hydrologic flow from the natal river and Uburst or Uslip. Further, Uburst velocities decreased from 51.8 cm s−1 (7.2 BL s−1) to 45.6 cm s−1 (6.3 BL s−1) by the third consecutive test suggesting the use of anaerobic metabolism. Uslip was not different between trials suggesting the use of aerobic metabolism in station-holding behaviours (Uslip). Moreover, we found no significant differences in individuals from the altered North Milk River system. Finally, individual caudal morphological characteristics were related to both slip and failure velocities. Our study contributes to the conservation of Rocky Mountain Sculpin by providing the first documentation of swimming and

  6. Comparative swimming and station-holding ability of the threatened Rocky Mountain Sculpin (Cottus sp.) from four hydrologically distinct rivers.

    PubMed

    Veillard, Marie F; Ruppert, Jonathan L W; Tierney, Keith; Watkinson, Douglas A; Poesch, Mark

    2017-01-01

    Hydrologic alterations, such as dams, culverts or diversions, can introduce new selection pressures on freshwater fishes, where they are required to adapt to novel environmental conditions. Our study investigated how species adapt to natural and altered stream flow, where we use the threatened Rocky Mountain Sculpin (Cottus sp.) as a model organism. We compared the swimming and station-holding performance of Rocky Mountain Sculpin from four different hydrologic regimes in Alberta and British Columbia, including the North Milk River, a system that experiences increased flows from a large-scale diversion. We measured the slip (Uslip) and failure (Uburst) velocities over three constant acceleration test trials. Uslip was defined as the point at which individuals required the addition of bursting or swimming to maintain position. Uburst was defined as the point at which individuals were unable to hold position in the swimming chamber through swimming, bursting or holding techniques without fully or partially resting on the electrified back plate. We found individuals from the Flathead River in British Columbia (with the highest natural flow) failed at significantly higher Uburst velocities than fish from the southern Albertan populations. However, there was no relationship between peak hydrologic flow from the natal river and Uburst or Uslip. Further, Uburst velocities decreased from 51.8 cm s(-1) (7.2 BL s(-1)) to 45.6 cm s(-1) (6.3 BL s(-1)) by the third consecutive test suggesting the use of anaerobic metabolism. Uslip was not different between trials suggesting the use of aerobic metabolism in station-holding behaviours (Uslip). Moreover, we found no significant differences in individuals from the altered North Milk River system. Finally, individual caudal morphological characteristics were related to both slip and failure velocities. Our study contributes to the conservation of Rocky Mountain Sculpin by providing the first documentation of swimming and station

  7. Habitat, biota, and sediment characteristics at selected stations in the lower Illinois River Basin, Illinois, 1996-98

    USGS Publications Warehouse

    Adolphson, Debbie L.; Fazio, David J.; Harris, Mitchell A.

    2001-01-01

    Data collection for the lower Illinois River Basin (LIRB) National Water-Quality Assessment (NAWQA) program began in 1996. Data on habitat, fish, benthic macroinvertebrates, and sediment were collected at eight stations on six streams in the basin--Illinois River, Panther Creek, Mackinaw River, Indian Creek, Sangamon River, and La Moine River. These streams typically flow through agricultural lands with very low gradients. Substrates typically are clay to gravel with areas of cobble. Banks are high, steep, and sparsely vegetated. Topographic surveys provide illustrations of the geometry that promote understanding of channel geometry and a data set that, in the future, can be used by others to assess stream changes. Suspended-sediment particle size, woody debris, and stream velocity are important to fish and benthic macroinvertebrate communities. Fine particles (silts and clays) were abundant in suspended sediment and stream banks, and fish insectivorous cyprinid community composition increased with decreases in the concentration of these suspended fines. Suckers were prevalent in stream reaches with abundant woody-snag cover, whereas sunfish communities were most abundant in areas with slow water velocities. Hydropsychidae, Chironomidae, and Baetidae were the most abundant benthic macroinvertebrate families collected throughout the region, but stream size and water velocity were important to benthic macroinvertebrate community composition. Tricorythodes mayflies and Elmidae had higher relative abundance at sites in small- and moderate-size drainage basins, and Baetidae density was greatest in reaches with highest water velocity.

  8. Statistical filtering of river survey and streamflow data for improving At-A-Station hydraulic geometry relations

    NASA Astrophysics Data System (ADS)

    Afshari, Shahab; Fekete, Balazs M.; Dingman, S. Lawrence; Devineni, Naresh; Bjerklie, David M.; Khanbilvardi, Reza M.

    2017-04-01

    Natural streams are characterized by variation in cross-section geometry, bed-slope, bed roughness, hydraulic slope, etc., along their channels resulting from several interacting features of the riverine system including the effects of discharge changes, geologic context, sediment load, etc. Quantitative and qualitative assessment of river flow dynamics requires sufficient knowledge of hydraulics and these geophysical variables. Average flow condition theory expressed as ;At-A-Station; hydraulic geometry (AHG) relations are site-specific power-functions, relating the mean stream channel forms (i.e. water depth, top-width, flow velocity, and flow area) to discharge, have been studied since 50s. Establishing robust AHG relations requires pre-assessment of data quality by means of uncertainty analysis. Our paper introduces a recursive data filtering procedure to find both random and systematic errors in streamflow and river-survey data that can be used to produce robust and informative AHG relations. The method is first verified on synthetic data and then by experiments over: (1) real discharge-stage ratings provided by daily streamflow records of U.S. Geological Survey/National Water Information System dataset (USGS/NWIS), and (2) field river survey measurement data from USGS/NWIS. This produces robust AHG relations at 4472 monitoring stations across the U.S.

  9. Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

    USGS Publications Warehouse

    Repert, Deborah A.; Underwood, Jennifer C.; Smith, Richard L.; Song, Bongkeun

    2014-01-01

    Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sediment samples collected over distinct water cycle seasons. In conjunction, the microbial community composition in the bed sediments using genes involved in N-cycling (narG, napA, nosZ, and amoA) and 16S rRNA gene pyrosequences was examined. Temporal variation was observed in net N mineralization, nitrate uptake, and denitrification rate potentials and correlated strongly with sediment carbon (C) and extractable N content and microbial community composition rather than with river water nutrient concentrations. The C content of the bed sediment was notably impacted by the spring flood, ranging from 1.1% in the midst of an ice-jam to 0.1% immediately after ice-out, suggesting a buildup of organic material (OM) prior to scouring of the bed sediments during ice break up. The dominant members of the microbial community that explained differences in N-processing rates belonged to the genera Crenothrix,Flavobacterium, and the family of Comamonadaceae. Our results suggest that biogeochemical processing rates in the bed sediments appear to be more coupled to hydrology, nutrient availability in the sediments, and microbial community composition rather than river nutrient concentrations at Pilot Station.

  10. Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

    NASA Astrophysics Data System (ADS)

    Repert, Deborah A.; Underwood, Jennifer C.; Smith, Richard L.; Song, Bongkeun

    2014-12-01

    Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sediment samples collected over distinct water cycle seasons. In conjunction, the microbial community composition in the bed sediments using genes involved in N-cycling (narG, napA, nosZ, and amoA) and 16S rRNA gene pyrosequences was examined. Temporal variation was observed in net N mineralization, nitrate uptake, and denitrification rate potentials and correlated strongly with sediment carbon (C) and extractable N content and microbial community composition rather than with river water nutrient concentrations. The C content of the bed sediment was notably impacted by the spring flood, ranging from 1.1% in the midst of an ice-jam to 0.1% immediately after ice-out, suggesting a buildup of organic material (OM) prior to scouring of the bed sediments during ice break up. The dominant members of the microbial community that explained differences in N-processing rates belonged to the genera Crenothrix, Flavobacterium, and the family of Comamonadaceae. Our results suggest that biogeochemical processing rates in the bed sediments appear to be more coupled to hydrology, nutrient availability in the sediments, and microbial community composition rather than river nutrient concentrations at Pilot Station.

  11. Analysis of minimum 7-day discharges and estimation of minimum 7-day, 2-year discharges for streamflow-gaging stations in the Brazos River basin, Texas

    USGS Publications Warehouse

    Raines, Timothy H.; Asquith, William H.

    1997-01-01

    The 7Q2 is zero for 31 of the 46 unregulated-only stations and for 9 of the 26 regulated-only stations. The 7Q2 also is zero for 9 stations before regulation and for 3 stations after regulation of the 25 stations with both unregulated and regulated data. The 7Q2 ranges from 33 to 631 cubic feet per second for the eight regulated-only stations on the mainstem Brazos River. For the seven stations on the mainstem Brazos River with at least 10 years of unregulated and 10 years of regulated discharge data, the 7Q2 ranges from 0 to 568 cubic feet per second before regulation and from 0.30 to 670 cubic feet per second after regulation. The 7Q2 increased during regulation for 19 of the 25 stations with both unregulated and regulated data. The effect of regulation for most stations generally was an increase in the magnitude of the 7Q2.

  12. Evaluating long-term trends in mean- and high- river flows using a network of reference stations in Ireland

    NASA Astrophysics Data System (ADS)

    Wilby, R. L.; Murphy, C.; Harrigan, S.; Hall, J.

    2012-12-01

    This paper describes the development of a reference hydrometric network for Ireland established primarily for the detection of climate driven trends in mean and high river flows. Thirty-five stations were identified for inclusion in the network plus a further 8 from the UK Benchmark Network. Their average record length is 40 years with a minimum of 28 and maximum of 63 years. Time series were derived for eight river flow indices: annual and seasonal mean flows and the annual maximum 1-, 10- and 30-day flows. Mann Kendall and Theil Sen statistics were applied to all indices using fixed and variable start/end dates. Trends in the winter mean are found to be highly dependent on the chosen period of analysis with the longest records showing increased flows. Contrary to expectations (of regional climate change scenarios), increases are also evident for long-term summer mean flows. High flow metrics exhibit positive and persistent trends that are less affected by inter-annual variability and period of record. Overall, there is strong spatial coherence in these patterns of change, linked to temporal variations in precipitation. Our results highlight the dangers of using conventional fixed periods such as 1961-1990 for trend detection, recognising that there is always a trade-off between record length, density of the network, and geographic coverage. Furthermore, outliers at the beginning of the record can be an artefact of the original motivation for installing the gauging station(s). In this case, water resource concerns during a markedly dry period in the mid-1970s favour positive trends over subsequent decades. Future work will focus on detection times for climate change signals and the identification of sentinel sites for discerning early signs of anthropogenic climate change across Ireland. Broader lessons for monitoring and detection of anthropogenic climate change signals will also be distilled.

  13. Principal facts for gravity stations in the Clearwater and Blackfoot River valleys, Montana

    USGS Publications Warehouse

    Wilson, Dolores M.

    1978-01-01

    A gravity survey was made in the Clearwater and Blackfoot River valleys to provide information on structural relationships and subsurface geology as part of the Big Fork-Avon environmental and land-use project undertaken by the U.S. Geological Survey and Missoula and Powell Counties, Montana.

  14. Rural Land Use in the Monongahela River Basin. [Agricultural Experiment Station] Bulletin 641.

    ERIC Educational Resources Information Center

    Akintola, Jacob; And Others

    In order to determine rural land use in the Monongahela River Basin, 11,528 landowners, controlling 40 percent of 10 contiguous counties in north-central West Virginia and constituting 19 percent of the rural population, were surveyed. Data derived from 892 questionnaire responses were analyzed in terms of past, present, and future land use; land…

  15. Low-flow characteristics at gaging stations on the Wisconsin, Fox, and Wolf rivers, Wisconsin

    USGS Publications Warehouse

    Gebert, W.A.; Holmstrom, B.K.

    1977-01-01

    The magnitude of the low-flow characteristics are in some instances affected by the period of record. These characteristics can vary as much as ±30 percent at some gaging stations depending on whether or not the severe drought of the 1930's was included in the analysis.

  16. Estimating Low-Flow Frequency Statistics and Hydrologic Analysis of Selected Streamflow-Gaging Stations, Nooksack River Basin, Northwestern Washington and Canada

    USGS Publications Warehouse

    Curran, Christopher A.; Olsen, Theresa D.

    2009-01-01

    Low-flow frequency statistics were computed at 17 continuous-record streamflow-gaging stations and 8 miscellaneous measurement sites in and near the Nooksack River basin in northwestern Washington and Canada, including the 1, 3, 7, 15, 30, and 60 consecutive-day low flows with recurrence intervals of 2 and 10 years. Using these low-flow statistics, 12 regional regression equations were developed for estimating the same low-flow statistics at ungaged sites in the Nooksack River basin using a weighted-least-squares method. Adjusted R2 (coefficient of determination) values for the equations ranged from 0.79 to 0.93 and the root-mean-squared error (RMSE) expressed as a percentage ranged from 77 to 560 percent. Streamflow records from six gaging stations located in mountain-stream or lowland-stream subbasins of the Nooksack River basin were analyzed to determine if any of the gaging stations could be removed from the network without significant loss of information. Using methods of hydrograph comparison, daily-value correlation, variable space, and flow-duration ratios, and other factors relating to individual subbasins, the six gaging stations were prioritized from most to least important as follows: Skookum Creek (12209490), Anderson Creek (12210900), Warm Creek (12207750), Fishtrap Creek (12212050), Racehorse Creek (12206900), and Clearwater Creek (12207850). The optimum streamflow-gaging station network would contain all gaging stations except Clearwater Creek, and the minimum network would include Skookum Creek and Anderson Creek.

  17. Long-term continuous acoustical suspended-sediment measurements in rivers – Theory, evaluation, and results from 14 stations on five rivers

    USGS Publications Warehouse

    Topping, David; Wright, Scott A.; Griffiths, Ronald; Dean, David

    2016-01-01

    We have developed a physically based method for using two acoustic frequencies to measure suspended-silt-and-clay concentration, suspended-sand concentration, and suspended-sand median grain size in river cross sections at 15-minute intervals over decadal timescales. The method is strongly grounded in the extensive scientific literature on the scattering of sound by suspensions of small particles. In particular, the method takes advantage of the specific theoretical relations among acoustic frequency, acoustic attenuation, acoustic backscatter, suspended-sediment concentration, and suspended-sediment grain-size distribution. We briefly describe the theory and methods, demonstrate the application of the method, and compute biases and errors in the method at 14 stations in the Colorado River and Rio Grande basins, where large numbers of suspended-sediment samples have been collected concurrently with acoustical measurements over many years. Quantification of errors in sediment-transport measurements made using this method is essential if the measurements are to be used effectively, e.g., to evaluate uncertainty in long-term sediment loads and budgets

  18. Big Bend National Park, TX, USA, Mexico

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Sierra del Carmen of Mexico, across the Rio Grande River from Big Bend National Park, TX, (28.5N, 104.0W) is centered in this photo. The Rio Grande River bisects the scene; Mexico to the east, USA to the west. The thousand ft. Boquillas limestone cliff on the Mexican side of the river changes colors from white to pink to lavender at sunset. This severely eroded sedimentary landscape was once an ancient seabed later overlaid with volcanic activity.

  19. Characteristics of sediment data and annual suspended-sediment loads and yields for selected lower Missouri River mainstem and tributary stations, 1976-2008

    USGS Publications Warehouse

    Heimann, David C.; Rasmussen, Patrick P.; Cline, Teri L.; Pigue, Lori M.; Wagner, Holly R.

    2010-01-01

    Suspended-sediment data from 18 selected surface-water monitoring stations in the lower Missouri River Basin downstream from Gavins Point Dam were used in the computation of annual suspended-sediment and suspended-sand loads for 1976 through 2008. Three methods of suspended-sediment load determination were utilized and these included the subdivision method, regression of instantaneous turbidity with suspended-sediment concentrations at selected stations, and regression techniques using the Load Estimator (LOADEST) software. Characteristics of the suspended-sediment and streamflow data collected at the 18 monitoring stations and the tabulated annual suspended-sediment and suspended-sand loads and yields are presented.

  20. Hardgrove grindability study of Powder River Basin and Appalachian coal components in the blend to a midwestern power station

    SciTech Connect

    Padgett, P.L.; Hower, J.C.

    1996-12-31

    Five coals representing four distinct coal sources blended at a midwestern power station were subjected to detailed analysis of their Hardgrove grindability. The coals are: a low-sulfur, high volatile A bituminous Upper Elkhorn No. 3 coal (Pike County, KY); a medium-sulfur, high volatile A bituminous Pittsburgh coal (southwestern PA); a low-sulfur, subbituminous Wyodak coal from two mines in the eastern Powder River Basin (Campbell County, WY). The feed and all samples processed in the Hardgrove grindability test procedure were analyzed for their maceral and microlithotype content. The high-vitrinite Pittsburgh coal and the relatively more petrographically complex Upper Elkhorn No. 3 coal exhibit differing behavior in grindability. The Pittsburgh raw feed, 16x30 mesh fraction (HGI test fraction), and the {minus}30 mesh fraction (HGI reject) are relatively similar petrographically, suggesting that the HGI test fraction is reasonably representative of the whole feed. The eastern Kentucky coal is not as representative of the whole feed, the HGI test fraction having lower vitrinite than the rejected {minus}30 mesh fraction. The Powder River Basin coals are high vitrinite and show behavior similar to the Pittsburgh coal.

  1. Innovation in monitoring: The U.S. Geological Survey Sacramento–San Joaquin River Delta, California, flow-station network

    USGS Publications Warehouse

    Burau, Jon; Ruhl, Cathy; Work, Paul

    2016-01-29

    The U.S. Geological Survey (USGS) installed the first gage to measure the flow of water into California’s Sacramento–San Joaquin River Delta from the Sacramento River in the late 1800s. Today, a network of 35 hydro-acoustic meters measure flow throughout the delta. This region is a critical part of California’s freshwater supply and conveyance system. With the data provided by this flow-station network—sampled every 15 minutes and updated to the web every hour—state and federal water managers make daily decisions about how much freshwater can be pumped for human use, at which locations, and when. Fish and wildlife scientists, working with water managers, also use this information to protect fish species affected by pumping and loss of habitat. The data are also used to help determine the success or failure of efforts to restore ecosystem processes in what has been called the “most managed and highly altered” watershed in the country.

  2. Uncertainty in annual streamflow and change in reservoir content data from selected surface-water gaging stations on the lower Colorado River

    USGS Publications Warehouse

    Anning, David W.

    2002-01-01

    The lower Colorado River is an important water resource for metropolitan populations, agriculture, and industry in California, Arizona, and Nevada. The Bureau of Reclamation (BOR) manages the river, releasing water stored in Lakes Mead, Mohave, and Havasu, and in other smaller reservoirs as needed so that it can be used by diverters. To help guide river management, streamflow and reservoir content are monitored at strategically located gaging stations along the lower Colorado River, its tributaries, and its diversions. The data obtained from these gaging stations, however, contain uncertainty and are only estimates of the ‘‘true’’ streamflow and reservoir content. As part of a cooperative project with the BOR, the U.S. Geological Survey (USGS) estimated the standard error of the annual discharge for calendar years 1995–99 at 14 streamflow-gaging stations and the standard error of the change in reservoir content at 2 reservoir-content gaging stations (table 1 and fig.1; Anning, 2002). These standard error estimates provide a measure of the random uncertainty for the annual data.

  3. [Health assessments of a military company stationed on the Maroni River in French Guiana].

    PubMed

    Lial, J P

    1999-01-01

    Over a 5 month period (October 1996 to February 1997), a rotating company of 146 servicemen belonging to the Navy Airborne 6th Regiment were assigned along the Maroni River in French Guyana. During this mission, the medical personnel treated 387 local residents. Etiologies comprised 51 malaria attacks including 46 involving Plasmodium falciparum and 4 rattlesnake envenomations. The most common cause of consultation by military personnel was mycotic and staphylococcal skin infections, but 5 cases involving poor acclimatization were treated during the hot and dry season. Seven malaria attacks involving Plasmodium falciparum including 2 that were severe occurred despite prophylaxis using chloroquine-proguanil. Treatment with halofantrine was successful in all but one case which required combined chemotherapy using quinine and doxycycline. Five cases of cutaneous leishmaniasis were observed in subjects involved in jungle training. No case of HIV infection was detected upon returning home since most personnel either followed the recommendation to abstain from sex (51 p. 100) or used a condom (90 p. 100 of personnel who had sexual relations). These data illustrate the health risks for mainland French nationals in the region of the Maroni River and underline the need for preventive measures and education.

  4. Feasibility of estimate sediment yield in the non-sediment monitoring station area - A case study of Alishan River watershed,Taiwan

    NASA Astrophysics Data System (ADS)

    Chang, ChiaChi; Chan, HsunChuan; Jia, YaFei; Zhang, YaoXin

    2017-04-01

    Due to the steep topography, frail geology and concentrated rainfall in wet season, slope disaster occurred frequently in Taiwan. In addition, heavy rainfall induced landslides in upper watersheds. The sediment yield on the slopeland affects the sediment transport in the river. Sediment deposits on the river bed reduce the river cross section and change the flow direction. Furthermore, it generates risks to residents' lives and property in the downstream. The Taiwanese government has been devoting increasing efforts on the sedimentary management issues and on reduction in disaster occurrence. However, due to the limited information on the environmental conditions in the upper stream, it is difficult to set up the sedimentary monitoring equipment. This study used the upper stream of the Qingshuei River, the Alishan River, as a study area. In August 2009, Typhoon Morakot caused the sedimentation of midstream and downstream river courses in the Alishan River. Because there is no any sediment monitoring stations within the Alishan River watershed, the sediment yield values are hard to determine. The objective of this study is to establish a method to analyze the event-landslide sediment transport in the river on the upper watershed. This study numerically investigated the sediment transport in the Alishan River by using the KINEROS 2 model developed by the United States Department of Agriculture and the CCHE1D model developed by the National Center for Computational Hydroscience and Engineering. The simulated results represent the morphology changes in the Alishan River during the typhoon events. The results consist of a critical strategy reference for the sedimentary management for the Alishan River watershed.

  5. Reversal bending fatigue testing

    DOEpatents

    Wang, Jy-An John; Wang, Hong; Tan, Ting

    2014-10-21

    Embodiments for apparatuses for testing reversal bending fatigue in an elongated beam are disclosed. Embodiments are configured to be coupled to first and second end portions of the beam and to apply a bending moment to the beam and create a pure bending condition in an intermediate portion of the beam. Embodiments are further configured to cyclically alternate the direction of the bending moment applied to the beam such that the intermediate portion of the beam cyclically bends in opposite directions in a pure bending condition.

  6. Surface-water-quality assessment of the Kentucky River Basin, Kentucky; fixed-station network and selected water-quality data, April 1987 through August 1991

    USGS Publications Warehouse

    Griffin, M.S.; Martin, G.R.; White, K.D.

    1994-01-01

    This report describes selected data-collection activities and the associated data collected during the Kentucky River Basin pilot study of the U.S. Geological Survey's National Water-Quality Assessment Program. The data are intended to provide a nationally consistent description and improved understanding of current water quality in the basin. The data were collected at seven fixed stations that represent stream cross sections where constituent transport and water-quality trends can be evaluated. The report includes descriptions of (1) the basin; (2) the design of the fixed-station network; (3) the fixed-station sites; (4) the physical and chemical measurements; (5) the methods of sample collection, processing, and analysis; and (6) the quality-assurance and quality-control procedures. Water-quality data collected at the fixed stations during routine periodic sampling and supplemental high-flow sampling from April 1987 to August 1991 are presented.

  7. Determination of base-flow characteristics at selected streamflow-gaging stations on the Mad River, Ohio

    USGS Publications Warehouse

    Koltun, G.F.

    1995-01-01

    This report describes the results of a study to estimate characteristics of base flow and sustained ground-water discharge at five streamflow-gaging stations on the Mad River in Ohio. The five streamflow-gaging stations are located at Zanesfield, near Urbana, at St. Paris Pike (at Eagle City), near Springfield, and near Dayton. The median of the annual-mean base flows, determined by means of hydrograph separation, ranged from 0.64 (ft3/s)/mi2 (cubic feet per second per square mile) at Zanesfield to 0.74 (ft3/s)/mi2 at St. Paris Pike. The median percentage of annual total streamflow attributed to base flow ranged from 61.8 percent at Zanesfield to 76.1 percent near Urbana. Estimates of an upper limit (or threshold) at which base flows can be considered to be composed predominately of sustained ground-water discharge were made by constructing and analyzing base- flow-duration curves. The sustained ground-water discharges (base flows less than or equal to the estimated sustained ground-water-discharge thresholds) are assumed to originate from ground-water- flow systems that are minimally affected by seasonal climatic changes. The median sustained ground- water discharge ranged from 0.11 (ft3/s)/mi2 at Zanesfield to 0.26 (ft3/s)/mi2 at St. Paris Pike (at Eagle City) and near Springfield. The median sustained ground-water discharge, expressed as a percentage of the median annual-mean base flow, ranged from 17.2 percent at Zanesfield to 38.6 percent near Springfield.

  8. A Current and Retrospective Landscape-Level C Budget for the Fluxnet-Canada Coastal British Columbia Station (Oyster River).

    NASA Astrophysics Data System (ADS)

    Trofymow, J. A.; Stinson, G.; Kurz, W.

    2006-12-01

    A retrospective carbon (C ) budget for the Fluxnet-Canada coastal BC Station (5 x 5 km Oyster River Area) for the period 1920 to 2005 was developed using the spatially-explicit version of the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3). CBM-CFS3 is an inventory-based C budget modeling tool that has been used to simulate forest C dynamics at national, regional, and operational scales. A current (circa 2000) forest inventory map for the Oyster River Area was compiled using data provided by forest companies (TimberWest and Island Timberlands). This inventory was overlaid with historic disturbance maps and orthophotographs to generate a coverage of forest cover polygons with unique disturbance histories. A 1920 timber cruise map was then used to help estimate the volume, cover type, and age of the forest in each polygon in 1920. Data were loaded into the CBM-CFS3 initialization routine and the model was then used to simulate the forest dynamics and C budget for the 85-year period. The C budget of the Oyster River Area is strongly tied to its disturbance history. In 1920, old-growth forest covered the majority of the study area and net C flux was neutral or small. In the 1930's and 40's, ground fires, clear-cut harvesting (using railroad logging), and slash burning resulted in a significant loss of biomass C and a substantial flux of C into dead organic matter, the atmosphere, and wood product pools (area net average C loss 5 - 20 Mg C/ha/yr). A gradual recovery of ecosystem C stocks followed this period of high disturbance activity but the area remained a significant C source, and did not become a net C sink until well into the 1950's. From 1960 through 1987 disturbance was minimal and the area remained a C sink (area average net uptake 2 - 6 Mg C/ha/yr). As harvesting of the second-growth forest began in the late 1980's, the C budget of the area was once again dominated by disturbances, albeit buffered by ongoing C uptake by living biomass in the

  9. Comparison of oxide- and metal-core behavior during CRBRP (Clinch River Breeder Reactor Plant) station blackout

    SciTech Connect

    Polkinghorne, S T; Atkinson, S A

    1986-01-01

    A resurrected concept that could significantly improve the inherently safe response of Liquid-Metal cooled Reactors (LMRs) during severe undercooling transients is the use of metallic fuel. Analytical studies have been reported on for the transient behavior of metal-fuel cores in innovative, inherently safe LMR designs. This paper reports on an analysis done, instead, for the Clinch River Breeder Reactor Plant (CRBRP) design with the only innovative change being the incorporation of a metal-fuel core. The SSC-L code was used to simulate a protected station blackout accident in the CRBRP with a 943 MWt Integral Fast Reactor (IFR) metal-fuel core. The results, compared with those for the oxide-fueled CRBRP, show that the margin to boiling is greater for the IFR core. However, the cooldown transient is more severe due to the faster thermal response time of metallic fuel. Some additional calculations to assess possible LMR design improvements (reduced primary system pressure losses, extended flow coastdown) are also discussed. 8 refs., 13 figs., 2 tabs.

  10. Hydrogeology of the Piney Point-Nanjemoy, Aquia, and Upper Patapsco Aquifers, Naval Air Station Patuxent River and Webster Outlying Field, St. Marys County, Maryland, 2000-06

    USGS Publications Warehouse

    Klohe, Cheryl A.; Kay, Robert T.

    2007-01-01

    Recent and projected population growth in southern Maryland continues to bring ground-water-quality and quantity issues to the forefront. Lithologic, borehole geophysical, water-level, and water-use data were compiled and interpreted to revise understanding of the hydrogeologic framework of the Piney Point-Nanjemoy, Aquia, and Upper Patapsco aquifers in southern Maryland, with emphasis on the Naval Air Station Patuxent River and Webster Outlying Field. Understanding of the hydrogeologic framework for the Upper Patapsco aquifer also has been revised based on the results of aquifer testing and water-quality sampling of two wells. The Piney Point-Nanjemoy aquifer is 50 to 70 feet thick, with a top altitude of 213 to 260 feet below the North American Vertical Datum of 1988 and a hydraulic conductivity of 2 feet per day at Naval Air Station Patuxent River and Webster Outlying Field. Ground-water withdrawals from the Piney Point-Nanjemoy aquifer have been minimal since 1999 and water levels in the aquifer have not changed substantially since the 1950s. An overall decline of about 2.5 feet has been observed since 1997, however. The Aquia aquifer is 100 to 145 feet thick, with a top altitude of approximately 450 feet below the North American Vertical Datum of 1988 and a hydraulic conductivity of 6 to 10 feet per day at Naval Air Station Patuxent River. The Aquia aquifer is approximately 50 feet thick, with a top altitude of 470 feet below sea level and a hydraulic conductivity of 6 to 10 feet per day at Webster Outlying Field. Water levels in the Aquia aquifer declined in response to increased withdrawals from the aquifer from the early 1940s through about 2000 at Naval Air Station Patuxent River and Webster Outlying Field, but have been generally stable from about 1999 through April 2006. The Upper Patapsco aquifer at the Naval Air Station Patuxent River and Webster Outlying Field consists of layers of sand interbedded with layers of clay that total over 200 feet in

  11. Statistical summaries of water-quality data for selected streamflow-gaging stations in the Red River of the North basin, North Dakota, Minnesota, and South Dakota

    USGS Publications Warehouse

    Macek-Rowland, Kathleen M.; Dressler, Valerie M.

    2002-01-01

    The quantity and quality of current and future water resources in the Red River of the North Basin in North Dakota, Minnesota, and South Dakota are concerns of people who reside within the basin. Additional water resources are needed because of recent growth in population, industry, and agriculture. How the management of current and future water-resources will impact water quality within the basin is a critical issue. Water-quality data, particularly for surface-water sources, will help water-resources managers make decisions about current and future water resources in the Red River of the North Basin. Statistical summaries of water-quality data for 43 streamflow-gaging stations in the Red River of the North Basin in North Dakota, Minnesota, and South Dakota are presented in this report. Statistical summaries include sample size, maximum, minimum, mean, and values for the 95th, 75th, 50th, 25th, and 5th percentiles.

  12. A statistical study of dayside diffuse aurora observed at Yellow River Station in Ny-Ålesund, Svalbard

    NASA Astrophysics Data System (ADS)

    Han, D.; Hu, Z.; Hu, H.; Yang, H.; Huang, D. H.; Chen, X.

    2014-12-01

    Chinese Yellow River Station (YRS), at Ny-Alesund, Svalbard is one of the few stations that can make longtime optical auroral observation at the cusp latitude in the dayside during the boreal winter season on the Earth. Since November 2003, an optical observation system consisting of three identical all-sky imagers supplied with the narrow band filters centered at 427.8, 557.5 and 630.0nm, has been installed at YRS, and the continuous observations providing us with an unprecedented opportunity to investigate some new properties of dayside aurora. Optical diffuse auroras are normally observed at the sub-aurora latitude in nightside on the ground. However, by using 7-year continuous observations obtained at YRS, we found that the diffuse auroras are very frequently observed on the dayside at the high latitude, i.e., near the cusp. We classified the dayside diffuse aurora into four primary categories. They are (1) Veiling Diffuse Aurora, which has no obvious morphological structure and clear boundaries, sometimes likes a thick cloud cover the entire sky, (2) Patch Diffuse Aurora, which is an aurora patch normally in ~10-100km in width and usually owns pulsating property; (3) Diffuse Arcs, which looks like an arc but is apparently different from the discrete auroral arcs in morphology, and (4) Pulsating Aurora, occurring with sparkling forms. We statistical studied how the occurrence of the four types of dayside diffuse auroras depends on the local time, magnetic activity, and solar wind conditions. We found that the occurrence of each type of dayside diffuse aurora shows a unimodal distribution with magnetic local time and their peaks are mostly appeared near the magnetic local noon. We also noted that ~92.2% of the dayside diffuse auroras is observed under low magnetic activity, i.e., Kp ≤ 3, and the dayside diffuse auroras prefer to be observed under IMF By<0 and Bz>0. Although previous studies suggested that the dayside diffuse aurora should be caused by wave

  13. Hydrodynamic Simulations of Physical Aquatic Habitat Availability for Pallid Sturgeon in the Lower Missouri River, at Yankton, South Dakota, Kenslers Bend, Nebraska, Little Sioux, Iowa, and Miami, Missouri, 2006-07

    USGS Publications Warehouse

    Jacobson, Robert B.; Johnson, Harold E.; Dietsch, Benjamin J.

    2009-01-01

    The objective of this study was to assess the sensitivity of habitat availability in the Lower Missouri River to discharge variation, with emphasis on habitats that might support spawning of the endangered pallid sturgeon. We constructed computational hydrodynamic models for four reaches that were selected because of evidence that sturgeon have spawned in them. The reaches are located at Miami, Missouri (river mile 259.6-263.5), Little Sioux, Iowa (river mile 669.6-673.5), Kenslers Bend, Nebraska (river mile 743.9-748.1), and Yankton, South Dakota reach (river mile 804.8-808.4). The models were calibrated for a range of measured flow conditions, and run for a range of discharges that might be affected by flow modifications from Gavins Point Dam. Model performance was assessed by comparing modeled and measured water velocities. A selection of derived habitat units was assessed for sensitivity to hydraulic input parameters (drag coefficient and lateral eddy viscosity). Overall, model results were minimally sensitive to varying eddy viscosity; varying lateral eddy viscosity by 20 percent resulted in maximum change in habitat units of 5.4 percent. Shallow-water habitat units were most sensitive to variation in drag coefficient with 42 percent change in unit area resulting from 20 percent change in the parameter value; however, no habitat unit value changed more than 10 percent for a 10 percent variation in drag coefficient. Sensitivity analysis provides guidance for selecting habitat metrics that maximize information content while minimizing model uncertainties. To assess model sensitivities arising from topographic variation from sediment transport on an annual time scale, we constructed separate models from two complete independent surveys in 2006 and 2007. The net topographic change was minimal at each site; the ratio of net topographic change to water volume in the reaches at 95 percent exceedance flow was less than 5 percent, indicating that on a reach

  14. Hydrodynamic simulations of physical aquatic habitat availability for Pallid Sturgeon in the Lower Missouri River, at Yankton, South Dakota, Kenslers Bend, Nebraska, Little Sioux, Iowa, and Miami, Missouri, 2006-07

    USGS Publications Warehouse

    Jacobson, Robert B.; Johnson, Harold E.; Dietsch, Benjamin J.

    2009-01-01

    The objective of this study was to assess the sensitivity of habitat availability in the Lower Missouri River to discharge variation, with emphasis on habitats that might support spawning of the endangered pallid sturgeon. We constructed computational hydrodynamic models for four reaches that were selected because of evidence that sturgeon have spawned in them. The reaches are located at Miami, Missouri (river mile 259.6–263.5), Little Sioux, Iowa (river mile 669.6–673.5), Kenslers Bend, Nebraska (river mile 743.9–748.1), and Yankton, South Dakota reach (river mile 804.8–808.4). The models were calibrated for a range of measured flow conditions, and run for a range of discharges that might be affected by flow modifications from Gavins Point Dam. Model performance was assessed by comparing modeled and measured water velocities.A selection of derived habitat units was assessed for sensitivity to hydraulic input parameters (drag coefficient and lateral eddy viscosity). Overall, model results were minimally sensitive to varying eddy viscosity; varying lateral eddy viscosity by 20 percent resulted in maximum change in habitat units of 5.4 percent. Shallow-water habitat units were most sensitive to variation in drag coefficient with 42 percent change in unit area resulting from 20 percent change in the parameter value; however, no habitat unit value changed more than 10 percent for a 10 percent variation in drag coefficient. Sensitivity analysis provides guidance for selecting habitat metrics that maximize information content while minimizing model uncertainties.To assess model sensitivities arising from topographic variation from sediment transport on an annual time scale, we constructed separate models from two complete independent surveys in 2006 and 2007. The net topographic change was minimal at each site; the ratio of net topographic change to water volume in the reaches at 95 percent exceedance flow was less than 5 percent, indicating that on a reach

  15. Ozone and fine particle in the western Yangtze River Delta: an overview of 1 yr data at the SORPES station

    NASA Astrophysics Data System (ADS)

    Ding, A. J.; Fu, C. B.; Yang, X. Q.; Sun, J. N.; Zheng, L. F.; Xie, Y. N.; Herrmann, E.; Nie, W.; Petäjä, T.; Kerminen, V.-M.; Kulmala, M.

    2013-06-01

    This work presents an overview of 1 yr measurements of ozone (O3) and fine particular matter (PM2.5) and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES), in the western part of the Yangtze River Delta (YRD) in eastern China. Ozone and PM2.5 showed strong seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and a formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1 yr period, suggesting a severe air pollution situation in this region. Case studies for typical O3 and PM2.5 episodes demonstrated that these episodes were generally associated with an air mass transport pathway over the mid-YRD, i.e., along the Nanjing-Shanghai axis with its city clusters, and showed that synoptic weather played an important role in air pollution, especially for O3. Agricultural burning activities caused high PM2.5 and O3 pollution during harvest seasons, especially in June. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the mid-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving air quality in these areas through collaborative control measures among different administrative regions.

  16. Ozone and fine particle in the western Yangtze River Delta: an overview of 1-yr data at the SORPES station

    NASA Astrophysics Data System (ADS)

    Ding, A. J.; Fu, C. B.; Yang, X. Q.; Sun, J. N.; Zheng, L. F.; Xie, Y. N.; Herrmann, E.; Petäjä, T.; Kerminen, V.-M.; Kulmala, M.

    2013-01-01

    This work presents an overview of 1-yr measurements of ozone (O3) and fine particular matter (PM2.5) and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES), in the western part of the Yangtze River Delta (YRD) in East China. O3 and PM2.5 showed distinguished seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and also indicates a substantial formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1-yr period, suggesting a severe air pollution situation in this region. Case studies for typical O3 and PM2.5 episodes demonstrated that these episodes were generally associated with an air mass transport pathway over the mid-YRD, i.e. along the Nanjing-Shanghai axis with its city clusters, and showed that synoptic weather played an important role in air pollution, especially for O3. Agricultural burning activities caused high PM2.5 and O3 pollution during harvest seasons, especially in June. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the middle-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region, especially for the burning episode days. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving air quality in these areas through collaborative control measures among different administrative regions.

  17. 33 CFR 334.430 - Neuse River and tributaries at Marine Corps Air Station Cherry Point, North Carolina; restricted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Marine Corps Air Station Cherry Point, North Carolina; restricted area and danger zone. 334.430 Section... Air Station Cherry Point, North Carolina; restricted area and danger zone. (a) The restricted area... Station, Cherry Point, North Carolina, extending from the mouth of Hancock Creek to a point approximately...

  18. 33 CFR 334.430 - Neuse River and tributaries at Marine Corps Air Station Cherry Point, North Carolina; restricted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Marine Corps Air Station Cherry Point, North Carolina; restricted area and danger zone. 334.430 Section... Air Station Cherry Point, North Carolina; restricted area and danger zone. (a) The restricted area... Station, Cherry Point, North Carolina, extending from the mouth of Hancock Creek to a point approximately...

  19. 33 CFR 334.430 - Neuse River and tributaries at Marine Corps Air Station Cherry Point, North Carolina; restricted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Marine Corps Air Station Cherry Point, North Carolina; restricted area and danger zone. 334.430 Section... Air Station Cherry Point, North Carolina; restricted area and danger zone. (a) The restricted area... Station, Cherry Point, North Carolina, extending from the mouth of Hancock Creek to a point approximately...

  20. 33 CFR 334.430 - Neuse River and tributaries at Marine Corps Air Station Cherry Point, North Carolina; restricted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Marine Corps Air Station Cherry Point, North Carolina; restricted area and danger zone. 334.430 Section... Air Station Cherry Point, North Carolina; restricted area and danger zone. (a) The restricted area... Station, Cherry Point, North Carolina, extending from the mouth of Hancock Creek to a point approximately...

  1. 33 CFR 334.430 - Neuse River and tributaries at Marine Corps Air Station Cherry Point, North Carolina; restricted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Marine Corps Air Station Cherry Point, North Carolina; restricted area and danger zone. 334.430 Section... Air Station Cherry Point, North Carolina; restricted area and danger zone. (a) The restricted area... Station, Cherry Point, North Carolina, extending from the mouth of Hancock Creek to a point approximately...

  2. Discovering Gee's Bend Quilts

    ERIC Educational Resources Information Center

    Johnson, Ann

    2008-01-01

    Gee's Bend is a small community near Selma, Alabama where cotton plantations filled the land before the Civil War. After the war, the freed slaves of the plantations worked as tenant farmers and founded an African-American community. In 2002, the women of this community brought international attention and acclaim to Gee's Bend through the art of…

  3. Discovering Gee's Bend Quilts

    ERIC Educational Resources Information Center

    Johnson, Ann

    2008-01-01

    Gee's Bend is a small community near Selma, Alabama where cotton plantations filled the land before the Civil War. After the war, the freed slaves of the plantations worked as tenant farmers and founded an African-American community. In 2002, the women of this community brought international attention and acclaim to Gee's Bend through the art of…

  4. Microhole Tubing Bending Report

    DOE Data Explorer

    Oglesby, Ken

    2012-01-01

    A downhole tubing bending study was made and is reported herein. IT contains a report and 2 excel spreadsheets to calculate tubing bending and to estimate contact points of the tubing to the drilled hole wall (creating a new support point).

  5. Application of continuous seismic-reflection techniques to delineate paleochannels beneath the Neuse River at US Marine Corps Air Station, Cherry Point, North Carolina

    USGS Publications Warehouse

    Cardinell, Alex P.

    1999-01-01

    A continuous seismic-reflection profiling survey was conducted by the U.S. Geological Survey on the Neuse River near the Cherry Point Marine Corps Air Station during July 7-24, 1998. Approximately 52 miles of profiling data were collected during the survey from areas northwest of the Air Station to Flanner Beach and southeast to Cherry Point. Positioning of the seismic lines was done by using an integrated navigational system. Data from the survey were used to define and delineate paleochannel alignments under the Neuse River near the Air Station. These data also were correlated with existing surface and borehole geophysical data, including vertical seismic-profiling velocity data collected in 1995. Sediments believed to be Quaternary in age were identified at varying depths on the seismic sections as undifferentiated reflectors and lack the lateral continuity of underlying reflectors believed to represent older sediments of Tertiary age. The sediments of possible Quaternary age thicken to the southeast. Paleochannels of Quaternary age and varying depths were identified beneath the Neuse River estuary. These paleochannels range in width from 870 feet to about 6,900 feet. Two zones of buried paleochannels were identified in the continuous seismic-reflection profiling data. The eastern paleochannel zone includes two large superimposed channel features identified during this study and in re-interpreted 1995 land seismic-reflection data. The second paleochannel zone, located west of the first paleochannel zone, contains several small paleochannels near the central and south shore of the Neuse River estuary between Slocum Creek and Flanner Beach. This second zone of channel features may be continuous with those mapped by the U.S. Geological Survey in 1995 using land seismic-reflection data on the southern end of the Air Station. Most of the channels were mapped at the Quaternary-Tertiary sediment boundary. These channels appear to have been cut into the older sediments

  6. Occipital bending in schizophrenia.

    PubMed

    Maller, Jerome J; Anderson, Rodney J; Thomson, Richard H; Daskalakis, Zafiris J; Rosenfeld, Jeffrey V; Fitzgerald, Paul B

    2017-01-01

    To investigate the prevalence of occipital bending (an occipital lobe crossing or twisting across the midline) in subjects with schizophrenia and matched healthy controls. Occipital bending prevalence was investigated in 37 patients with schizophrenia and 44 healthy controls. Ratings showed that prevalence was nearly three times higher among schizophrenia patients (13/37 [35.1%]) than in control subjects (6/44 [13.6%]). Furthermore, those with schizophrenia had greater normalized gray matter volume but less white matter volume and had larger brain-to-cranial ratio. The results suggest that occipital bending is more prevalent among schizophrenia patients than healthy subjects and that schizophrenia patients have different gray matter-white matter proportions. Although the cause and clinical ramifications of occipital bending are unclear, the results infer that occipital bending may be a marker of psychiatric illness.

  7. Analysis of Flood-Magnitude and Flood-Frequency Data for Streamflow-Gaging Stations in the Delaware and North Branch Susquehanna River Basins in Pennsylvania

    USGS Publications Warehouse

    Roland, Mark A.; Stuckey, Marla H.

    2007-01-01

    The Delaware and North Branch Susquehanna River Basins in Pennsylvania experienced severe flooding as a result of intense rainfall during June 2006. The height of the flood waters on the rivers and tributaries approached or exceeded the peak of record at many locations. Updated flood-magnitude and flood-frequency data for streamflow-gaging stations on tributaries in the Delaware and North Branch Susquehanna River Basins were analyzed using data through the 2006 water year to determine if there were any major differences in the flood-discharge data. Flood frequencies for return intervals of 2, 5, 10, 50, 100, and 500 years (Q2, Q5, Q10, Q50, Q100, and Q500) were determined from annual maximum series (AMS) data from continuous-record gaging stations (stations) and were compared to flood discharges obtained from previously published Flood Insurance Studies (FIS) and to flood frequencies using partial-duration series (PDS) data. A Wilcoxon signed-rank test was performed to determine any statistically significant differences between flood frequencies computed from updated AMS station data and those obtained from FIS. Percentage differences between flood frequencies computed from updated AMS station data and those obtained from FIS also were determined for the 10, 50, 100, and 500 return intervals. A Mann-Kendall trend test was performed to determine statistically significant trends in the updated AMS peak-flow data for the period of record at the 41 stations. In addition to AMS station data, PDS data were used to determine flood-frequency discharges. The AMS and PDS flood-frequency data were compared to determine any differences between the two data sets. An analysis also was performed on AMS-derived flood frequencies for four stations to evaluate the possible effects of flood-control reservoirs on peak flows. Additionally, flood frequencies for three stations were evaluated to determine possible effects of urbanization on peak flows. The results of the Wilcoxon signed

  8. Groundwater quality and occurrence and distribution of selected constituents in the Aquia and Upper Patapsco aquifers, Naval Air Station Patuxent River, St. Mary's County, Maryland, July 2008

    USGS Publications Warehouse

    Dieter, Cheryl A.; Campo, Kimberly W.; Baker, Anna C.

    2012-01-01

    The Naval Air Station Patuxent River in southern Maryland has continued to expand in the first decade of the 21st century, contributing to rapid population growth in the surrounding area. The increase in population has caused State and County water managers and others to be concerned about the impact of population growth on the quantity and quality of groundwater supplies. The U.S. Geological Survey has been investigating the groundwater resources of the air station since 1998. As part of that ongoing investigation, groundwater was sampled in 2008 in six wells in the Aquia aquifer and two wells in the Upper Patapsco aquifer in the vicinity of Naval Air Station Patuxent River and Webster Outlying Field. Groundwater samples were analyzed for basic chemistry (field parameters, major ions, and nutrients) as well as several water-quality issues of concern including the occurrence of arsenic and tungsten, and saltwater intrusion. The results of the 2008 groundwater-quality sampling indicate that the overall quality of groundwater in the Aquia aquifer has not changed since 1943; data are too limited to determine if groundwater quality has changed in the Upper Patapsco aquifer. At one well in the Aquia aquifer, the arsenic concentration exceeded the U.S. Environmental Protection Agency standard for drinking water. Arsenic was not detected in samples from the Upper Patapsco aquifer. Tungsten concentrations were detected at low concentrations near the laboratory reporting level in all eight samples. There was no evidence of saltwater intrusion in any of the wells.

  9. Backed Bending Actuator

    NASA Technical Reports Server (NTRS)

    Costen, Robert C.; Su, Ji

    2004-01-01

    Bending actuators of a proposed type would partly resemble ordinary bending actuators, but would include simple additional components that would render them capable of exerting large forces at small displacements. Like an ordinary bending actuator, an actuator according to the proposal would include a thin rectangular strip that would comprise two bonded layers (possibly made of electroactive polymers with surface electrodes) and would be clamped at one end in the manner of a cantilever beam. Unlike an ordinary bending actuator, the proposed device would include a rigid flat backplate that would support part of the bending strip against backward displacement; because of this feature, the proposed device is called a backed bending actuator. When an ordinary bending actuator is inactive, the strip typically lies flat, the tip displacement is zero, and the force exerted by the tip is zero. During activation, the tip exerts a transverse force and undergoes a bending displacement that results from the expansion or contraction of one or more of the bonded layers. The tip force of an ordinary bending actuator is inversely proportional to its length; hence, a long actuator tends to be weak. The figure depicts an ordinary bending actuator and the corresponding backed bending actuator. The bending, the tip displacement (d(sub t)), and the tip force (F) exerted by the ordinary bending actuator are well approximated by the conventional equations for the loading and deflection of a cantilever beam subject to a bending moment which, in this case, is applied by the differential expansion or contraction of the bonded layers. The bending, displacement, and tip force of the backed bending actuator are calculated similarly, except that it is necessary to account for the fact that the force F(sub b) that resists the displacement of the tip could be sufficient to push part of the strip against the backplate; in such a condition, the cantilever beam would be effectively shortened

  10. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  11. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  12. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  13. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  14. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  15. Benthic studies to assess thermal impacts of the H. A. Wagner Steam Electric Station, Patapsco River, Maryland. Final report Jun 81-Feb 82

    SciTech Connect

    Heck, K.L.; Osman, R.W.

    1982-07-15

    In July 1980, a study was initiated to estimate the effects of the H. A. Wagner Steam Electric Station (SES) on the benthic and finfish assemblages of Baltimore's Outer Harbor and the Patapsco River. This benthic study, conducted from July 1980 to early June 1981, was designed to determine whether shifts in benthic species composition and abundance, out-of-phase reproductive activity, or altered patterns of recruitment occur in thermally affected areas. A sixth transect with three sampling stations was added because this transect was adjacent to the Wagner SES and in an area scheduled for dredging. In addition to examining thermal effects, an assessment was made of the extent to which dredging and nearby sources of heavy-metal pollution contributed to or were responsible for observed differences.

  16. Understanding Aggregation and Estimating Seasonal Abundance of Chrysaora quinquecirrha Medusae from a Fixed-station Time Series in the Choptank River, Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Tay, J.; Hood, R. R.

    2016-02-01

    Although jellyfish exert strong control over marine plankton dynamics (Richardson et al. 2009, Robison et al. 2014) and negatively impact human commercial and recreational activities (Purcell et al. 2007, Purcell 2012), jellyfish biomass is not well quantified due primarily to sampling difficulties with plankton nets or fisheries trawls (Haddock 2004). As a result, some of the longest records of jellyfish are visual shore-based surveys, such as the fixed-station time series of Chrysaora quinquecirrha that began in 1960 in the Patuxent River in Chesapeake Bay, USA (Cargo and King 1990). Time series counts from fixed-station surveys capture two signals: 1) demographic change at timescales on the order of reproductive processes and 2) spatial patchiness at shorter timescales as different parcels of water move in and out of the survey area by tidal and estuarine advection and turbulent mixing (Lee and McAlice 1979). In this study, our goal was to separate these two signals using a 4-year time series of C. quinquecirrha medusa counts from a fixed-station in the Choptank River, Chesapeake Bay. Idealized modeling of tidal and estuarine advection was used to conceptualize the sampling scheme. Change point and time series analysis was used to detect demographic changes. Indices of aggregation (Negative Binomial coefficient, Taylor's Power Law coefficient, and Morisita's Index) were calculated to describe the spatial patchiness of the medusae. Abundance estimates revealed a bloom cycle that differed in duration and magnitude for each of the study years. Indices of aggregation indicated that medusae were aggregated and that patches grew in the number of individuals, and likely in size, as abundance increased. Further inference from the conceptual modeling suggested that medusae patch structure was generally homogenous over the tidal extent. This study highlights the benefits of using fixed-station shore-based surveys for understanding the biology and ecology of jellyfish.

  17. Simulation of Ground-Water Flow and Optimization of Withdrawals from Aquifers at the Naval Air Station Patuxent River, St. Mary's County, Maryland

    USGS Publications Warehouse

    Dieter, Cheryl A.; Fleck, William B.

    2008-01-01

    Potentiometric surfaces in the Piney Point-Nanjemoy, Aquia, and Upper Patapsco aquifers have declined from 1950 through 2000 throughout southern Maryland. In the vicinity of Lexington Park, Maryland, the potentiometric surface in the Aquia aquifer in 2000 was as much as 170 feet below sea level, approximately 150 feet lower than estimated pre-pumping levels before 1940. At the present rate, the water levels will have declined to the regulatory allowable maximum of 80 percent of available drawdown in the Aquia aquifer by about 2050. The effect of the withdrawals from these aquifers by the Naval Air Station Patuxent River and surrounding users on the declining potentiometric surface has raised concern for future availability of ground water. Growth at Naval Air Station Patuxent River may increase withdrawals, resulting in further drawdown. A ground-water-flow model, combined with optimization modeling, was used to develop withdrawal scenarios that minimize the effects (drawdown) of hypothetical future withdrawals. A three-dimensional finite-difference ground-water-flow model was developed to simulate the ground-water-flow system in the Piney Point-Nanjemoy, Aquia, and Upper Patapsco aquifers beneath the Naval Air Station Patuxent River. Transient and steady-state conditions were simulated to give water-resource managers additional tools to manage the ground-water resources. The transient simulation, representing 1900 through 2002, showed that the magnitude of withdrawal has increased over that time, causing ground-water flow to change direction in some areas. The steady-state simulation was linked to an optimization model to determine optimal solutions to hypothetical water-management scenarios. Two optimization scenarios were evaluated. The first scenario was designed to determine the optimal pumping rates for wells screened in the Aquia aquifer within three supply groups to meet a 25-percent increase in withdrawal demands, while minimizing the drawdown at a control

  18. "A shape bend in the road, showing how the horses ...

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

    "A shape bend in the road, showing how the horses are hitched in 'blocking.' The remainder of the team has been hitched to the block and tackle." San Joaquin Light and Power Magazine, Vol. I, No. 12, December 1913, p. 553 - Tule River Hydroelectric Complex, CA Highway 190 at North Fork of Middle Fork of Tule River, Springville, Tulare County, CA

  19. Reconstructing meteorological time series to quantify the uncertainties of runoff simulation in the ungauged Qira River Basin using data from multiple stations

    NASA Astrophysics Data System (ADS)

    Xue, Jie; Gui, Dongwei; Lei, Jiaqiang; Feng, Xinlong; Zeng, Fanjiang; Zhou, Jie; Mao, Donglei

    2016-10-01

    The existence and development of oases in arid plain areas depends mainly on the runoff generated from alpine regions. Quantifying the uncertainties of runoff simulation under climatic change is crucial for better utilization of water resources and management of oases in arid areas. In the present study, based on the ungauged Qira River Basin in Xinjiang, China, a modified version of the Delta statistical downscaling method was applied to reconstruct the monthly mean temperature (MMT), monthly accumulated precipitation (MAP), and monthly accumulated evaporation (MAE) of two target stations. Then, the uncertainty in runoff simulation, implemented using the Three-Layered Feedforward Neural Network model with the Back-Propagation learning algorithm, was quantified. The modified Delta method reproduced the MMT, MAP, and MAE time series of the two target stations very well during the calibrated periods, and the reconstructed uncertainty ranges were small among reconstructed datasets using data from 12 observation stations. The monthly accumulated runoff simulated by the reconstructed MMT, MAP, and MAE as input variables of the model possessed unpredictable uncertainty. Although the use of multi-data ensembles in model inputs are considered an effective way to minimize uncertainties, it could be concluded that, in this case, the efficiency of such an approach was limited because of errors in the meteorological data and the deficiency of the model's structure. The uncertainty range in the runoff peak was unable to capture the actual monthly runoff. Nevertheless, this study represents a significant attempt to reproduce historical meteorological data and to evaluate the uncertainties in runoff simulation through multiple input ensembles in an ungauged basin. It can be used as reference meteorological data for researching long-term climate change and producing runoff forecasts for assessing the risk of droughts and/or floods, as well as the existence and management of plain

  20. Rivers

    USGS Publications Warehouse

    Leopold, Luna Bergere

    1962-01-01

    Rivers are both the means and the routes by which the products of continental weathering are carried to the oceans of the world. Except in the most arid areas more water falls as precipitation than is lost by evaporation and transpiration from the land surface to the atmosphere. Thus there is an excess of water, which must flow to the ocean. Rivers, then, are the routes by which this excess water flows to the ultimate base level. The excess of precipitation over evaporation and transpiration provides the flow of rivers and springs, recharges ground-water storage, and is the supply from which man draws water for his needs.

  1. Dispersion suppressors with bending

    SciTech Connect

    Garren, A.

    1985-10-01

    Dispersion suppressors of two main types are usually used. In one the cell quadrupole focussing structure is the same as in normal cells but some of the dipoles are replaced by drifts. In the other, the quadrupole strengths and/or spacings are different from those of the normal cells, but the bending is about the same as it is in the cells. In SSC designs to date, dispersion suppressors of the former type have been used, consisting of two cells with bending equivalent to one. In this note a suppressor design with normal bending and altered focussing is presented. The advantage of this scheme is that circumference is reduced. The disadvantages are that additional special quadrupoles must be provided (however, they need not be adjustable), and the maximum beta values within them are about 30% higher than the cell maxima.

  2. A progress report on the Malaga Bend Experimental Salinity Alleviation Project, Eddy County, New Mexico

    USGS Publications Warehouse

    Cox, E.R.; Havens, J.S.

    1965-01-01

    At Malaga Bend on the Pecos River in Eddy County, New Mexico, a brine aquifer about 1950 feet below the stream channel has a pressure head about 10 feet above the river bed. This aquifer normally discharges about 430 tons of dissolved minerals daily into the river of which about 370 tons was sodium chloride. The Malaga Bend Experimental Salinity Alleviation Project, authorized by the U.S. Congress in 1958, Public Law 85-333,is an attempt to determine if the salinity content of the Pecos River below Malaga Bend can be decreased by reducing the inflow of saline water into the river at Malaga Bend by pumping from the brine aquifer. Construction for the project was supervised by the Bureau of Reclamation, and the collection of data and its interpretation were the responsibility cooperatively of the U. S. Geological Survey and the Pecos River Commission.

  3. Two-dimensional resistivity investigation along West Fork Trinity River, Naval Air Station-Joint Reserve Base, Carswell Field, Fort Worth, Texas, October 2004

    USGS Publications Warehouse

    Shah, Sachin D.; Stanton, Gregory P.

    2006-01-01

    Naval Air Station-Joint Reserve Base Carswell Field (NAS-JRB) at Fort Worth, Tex., constitutes a government-owned, contractor-operated facility that has been in operation since 1942. Contaminants, primarily volatile organic compounds and metals, have entered the ground-water-flow system through leakage from waste-disposal sites and manufacturing processes. Ground water flows from west to east toward the West Fork Trinity River. During October 2004, the U.S. Geological Survey conducted a two-dimensional (2D) resistivity investigation at a site along the West Fork Trinity River at the eastern boundary of NAS-JRB to characterize the distribution of subsurface resistivity. Five 2D resistivity profiles were collected, which ranged from 500 to 750 feet long and extended to a depth of 25 feet. The Goodland Limestone and the underlying Walnut Formation form a confining unit that underlies the alluvial aquifer. The top of this confining unit is the top of bedrock at NAS-JRB. The bedrock confining unit is the zone of interest because of the potential for contaminated ground water to enter the West Fork Trinity River through saturated bedrock. The study involved a capacitively-coupled resistivity survey and inverse modeling to obtain true or actual resistivity from apparent resistivity. The apparent resistivity was processed using an inverse modeling software program. The results of this program were used to generate distributions (images) of actual resistivity referred to as inverted sections or profiles. The images along the five profiles show a wide range of resistivity values. The two profiles nearest the West Fork Trinity River generally showed less resistivity than the three other profiles.

  4. Occipital bending in depression.

    PubMed

    Maller, Jerome J; Thomson, Richard H S; Rosenfeld, Jeffrey V; Anderson, Rodney; Daskalakis, Zafiris J; Fitzgerald, Paul B

    2014-06-01

    There are reports of differences in occipital lobe asymmetry within psychiatric populations when compared with healthy control subjects. Anecdotal evidence and enlarged lateral ventricles suggests that there may also be a different pattern of curvature whereby one occipital lobe wraps around the other, termed 'occipital bending'. We investigated the prevalence of occipital bending in 51 patients with major depressive disorder (males mean age = 41.96 ± 14.00 years, females mean age = 40.71 ± 12.41 years) and 48 age- and sex-matched healthy control subjects (males mean age = 40.29 ± 10.23 years, females mean age = 42.47 ± 14.25 years) and found the prevalence to be three times higher among patients with major depressive disorder (18/51, 35.3%) when compared with control subjects (6/48, 12.5%). The results suggest that occipital bending is more common among patients with major depressive disorder than healthy subjects, and that occipital asymmetry and occipital bending are separate phenomena. Incomplete neural pruning may lead to the cranial space available for brain growth being restricted, or ventricular enlargement may exacerbate the natural occipital curvature patterns, subsequently causing the brain to become squashed and forced to 'wrap' around the other occipital lobe. Although the clinical implications of these results are unclear, they provide an impetus for further research into the relevance of occipital bending in major depression disorder. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Hydrological variability from gauging stations and simulated SWOT data, for major French rivers over the past decades

    NASA Astrophysics Data System (ADS)

    Chevalier, Laetitia; Laignel, Benoit; Turki, Imen; Lyard, Florent; Lion, Christine

    2014-05-01

    This study was carried out in the framework of the program Surface Water and Ocean Topography (SWOT) associated to the National Center of Space Studies (CNES). Basing on discharge measurements, and simulated Surface Water and Ocean Topography (SWOT) data, we have investigated the hydrological variability of the main French rivers (Seine, Loire, Garonne and Rhône) by the use of a minimum, maximum and mean annual discharge analyses, Loess and wavelet approach (continuous wavelet analyses and wavelet coherence analyses). Results show (i) strong coherence between the four watershed discharges, varying between 73% and 92% and (ii) three different periods for hydrological variability: before 1970, between 1970 and 1990, and after 1990. From these results, simulated SWOT data and discharges are compared for these three periods using same analyses. Simulated SWOT data are obtained by re-sampling river discharges from the SWOT crossing time calculated. Simulated SWOT data can reproduce the hydrological variability of rivers despite number of SWOT passages (from two to four). These results are validated by coherence wavelet, which underlines coherence higher than 90% between simulated SWOT data and in-situ discharge. However, the results indicate that simulated SWOT data don't reproduce exactly the minimum and maximum annual discharge: (i) maximum annual SWOT data are underestimated and (ii) minimum annual SWOT data are overestimated

  6. Velocity and Scour Prediction in River Bends

    DTIC Science & Technology

    1993-03-01

    these secondary currents which are responsible for the accelaration of near bank primary velocities in the outer bank region. Consequently, the...different forces acting on bed-material particles to produce an equilibrium bed topography. All flow models start with the equations of motion for fluid flow...forces directed inwards and outwards on each bed particle are balanced (Allen, 1970; Bridge,1977). This means that particles of different sizes travel

  7. Analysis of watersheds monitored by the U.S. Geological Survey streamflow-gaging station network in the Upper Colorado River Basin

    USGS Publications Warehouse

    Kenney, Terry A.; Buto, Susan G.; Susong, David D.

    2011-01-01

    The U.S. Geological Survey (USGS) has operated streamflow-gaging stations in 1,053 watersheds in the Upper Colorado River Basin (UCRB) since 1894. Currently, 223 of these streamgages are active. This report presents selected watershed characteristics for 10,338 watersheds in the UCRB. These watersheds are compared to the watersheds upstream of USGS streamgages to assess how well the USGS streamgage network represents the physical characteristics of the watersheds in the entire basin. To conduct this assessment, 17 watershed characteristics, including physiographic parameters, land cover types, lithology, and parameters that describe anthropogenic influence, were computed for each of the gaging station drainage basins. The set of 10,338 watersheds in the UCRB was constructed from a previously developed stream-reach network, and the same 17 basin characteristics were computed for each watershed to facilitate comparisons. The USGS streamgage watersheds and the UCRB watersheds were split into those that are currently unaffected by upstream reservoir regulation and those currently affected by upstream reservoir regulation. In general, for unregulated watersheds, the streamgage network represents the range of most basin characteristics in the watersheds of the UCRB. However, the active streamgage network for unregulated watersheds is generally lacking in representation of most basin characteristics compared with watersheds in the UCRB. At regulated locations, the streamgage network including the active network, generally represents the range of most basin characteristics well.

  8. Hydrometry's classical and Innovative methods and tools comparison for Stara river flows at Agios Germanos monitoring station in north-west Greece.

    NASA Astrophysics Data System (ADS)

    Filintas, Agathos, , Dr; Hatzigiannakis, Evagellos, , Dr; Arampatzis, George, , Dr; Ilias, Andreas; Panagopoulos, Andreas, , Dr; Hatzispiroglou, Ioannis

    2015-04-01

    The aim of the present study is a thorough comparison of hydrometry's conventional and innovative methods-tools for river flow monitoring. A case study was conducted in Stara river at Agios Germanos monitoring station (northwest Greece), in order to investigate possible deviations between conventional and innovative methods-tools on river flow velocity and discharge. For this study, two flowmeters were used, which manufac-tured in 2013 (OTT Messtechnik Gmbh, 2013), as follows: a) A conventional propeller flow velocity meter (OTT-Model C2) which is a me-chanical current flow meter with a certification of calibration BARGO, operated with a rod and a relocating device, along with a digital measuring device including an elec-tronic flow calculator, data logger and real time control display unit. The flowmeter has a measurement velocity range 0.025-4.000 m/s. b) An innovative electromagnetic flowmeter (OTT-Model MF pro) which it is con-sisted of a compact and light-weight sensor and a robust handheld unit. Both system components are designed to be attached to conventional wading rods. The electromag-netic flowmeter uses Faraday's Law of electromagnetic induction to measure the process flow. When an electrically conductive fluid flows along the meter, an electrode voltage is induced between a pair of electrodes placed at right angles to the direction of mag-netic field. The electrode voltage is directly proportional to the average fluid velocity. The electromagnetic flowmeter was operated with a rod and relocating device, along with a digital measuring device with various logging and graphical capabilities and vari-ous methods of velocity measurement (ISO/USGS standards). The flowmeter has a measurement velocity range 0.000-6.000 m/s. The river flow data were averaged over a pair measurement of 60+60 seconds and the measured river water flow velocity, depths and widths of the segments were used for the estimation of cross-section's mean flow velocity in each measured

  9. [Limnetic zooplankton run-off a high-head dam and their fate in a river with high current velocity (case of the Krasnoiarsk hydroelectric power station on the Yenisei river].

    PubMed

    Dubovskaia, O P; Gladyshev, M I; Makhutova, O N

    2004-01-01

    The vertical distribution of net zooplankton in head-water of Krasnoyarsk hydroelectric power station and its horizontal distribution in the tail-water were studied during two years in winter and summer seasons. In order to distinguish living and dead individuals the special staining was used. It was revealed that on average 77% of living plankton pass through high-head dam with deep water scoop to the tailwater. While passing through dam aggregates some individuals of the reservoir plankton are traumatized and die, that results in some increase of portion of dead individuals in the tail water near dam (from 3 to 6%). Alive zooplankton passed through the dam aggregates is eliminated under the Upper Yenisei highly turbulent conditions. There is approximately 10% of it in 32 km from the dam if compare with biomass in 20-40 m layer of reservoir, the portion of dead increases to 11%. The biomass of zooplankton suspended in the water column of the tail-water sometimes increases (till > 1 g/m3) due to large Copepoda Heteroscope borealis, which inhabits near-bottom and near-shore river zones and can be found in the central part of the river during reproductive period. Limnetic zooplankton from the reservoir cannot be considered as important food for planktivores in the tail-water.

  10. Big Bend sees big environmental push

    SciTech Connect

    Blankinship, S.

    2007-10-15

    The 1800 MW Big Bend Power Station is a coal-fired facility in Tampa Bay, Florida, USA owned by Tampa Electric. It has four pulverized coal- fired steam units equipped with FGD scrubbers and electrostatic precipitators. Currently the addition of selective catalytic reduction (SCR) systems is under consideration. The Unit 4 SCR retrofit was completed in June 2007; the remaining three systems are scheduled for completion by 2010. Boiler draft systems will be modified to a balance draft design to accommodate the increased pressure drop of the new systems. 3-D computer models were developed to determine constructability due to the tight clearance at the site. 1 photo.

  11. 2. VIEW OF CENTRAL BEND OF LOWER DIAGONAL NO. 1 ...

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

    2. VIEW OF CENTRAL BEND OF LOWER DIAGONAL NO. 1 DRAIN, LOOKING 2932 EAST OF NORTH. - Truckee-Carson Irrigation District, Lower Diagonal No. 1 Drain, Bounded by West Gate Road & Weapons Delivery Road, Naval Air Station Fallon, Fallon, Churchill County, NV

  12. 10. MOVABLE BED SEDIMENTATION MODELS. DOGTOOTH BEND MODEL (MODEL SCALE: ...

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

    10. MOVABLE BED SEDIMENTATION MODELS. DOGTOOTH BEND MODEL (MODEL SCALE: 1' = 400' HORIZONTAL, 1' = 100' VERTICAL), AND GREENVILLE BRIDGE MODEL (MODEL SCALE: 1' = 360' HORIZONTAL, 1' = 100' VERTICAL). - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  13. Maximum outer-bank velocity reduction for vane-dike fields installed in channel bends

    Treesearch

    S. Michael Scurlock; Amanda L. Cox; Christopher I. Thornton; Drew C. Baird

    2011-01-01

    Hydraulic conditions associated with channel bends in meandering rivers include secondary, helical currents, mass shift of flow to the outside of the bend, and increased erosion along the outer streambank. Such outer-bank erosion may result in undesired plan-form migration of the stream course, placing valuable land holdings or infrastructure in jeopardy. A type of in-...

  14. Bending the Rings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Saturn's rings appear strangely warped in this view of the rings seen through the upper Saturn atmosphere.

    The atmosphere acts like a lens in refracting (bending) the light reflected from the rings. As the rings pass behind the overexposed limb (edge) of Saturn as seen from Cassini, the ring structure appears to curve downward due to the bending of the light as it passes through the upper atmosphere.

    This image was obtained using a near-infrared filter. The filter samples a wavelength where methane gas does not absorb light, thus making the far-off rings visible through the upper atmosphere.

    By comparing this image to similar ones taken using filters where methane gas does absorb, scientists can estimate the vertical profile of haze and the abundance of methane in Saturn's high atmosphere.

    The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 14, 2005, through a filter sensitive to wavelengths of infrared light centered at 938 nanometers and at a distance of approximately 197,000 kilometers (123,000 miles) from Saturn. The image scale is 820 meters (2,680 feet) per pixel.

  15. Light bending in radiation background

    SciTech Connect

    Kim, Jin Young; Lee, Taekoon E-mail: tlee@kunsan.ac.kr

    2014-01-01

    We consider the velocity shift of light in presence of radiation emitted by a black body. Within geometric optics formalism we calculate the bending angle of a light ray when there is a gradient in the energy density. We model the bending for two simplified cases. The bending angle is proportional to the inverse square power of the impact parameter (∝1/b{sup 2}) when the dilution of energy density is spherically symmetric. The bending angle is inversely proportional to the impact parameter (∝1/b) when the energy density dilutes cylindrically. Assuming that a neutron star is an isothermal black body, we estimate the order of magnitude for such bending angle and compare it with the bending angle by magnetic field.

  16. 2. TELEPHOTO VIEW OF CHESTER STATION COMPLEX FROM THE SOUTH ...

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

    2. TELEPHOTO VIEW OF CHESTER STATION COMPLEX FROM THE SOUTH SIDE OF THE COMMODORE BARRY BRIDGE THAT SPANS THE DELAWARE RIVER - Delaware County Electric Company, Chester Station, Delaware River at South end of Ward Street, Chester, Delaware County, PA

  17. Phase trombones with bending

    SciTech Connect

    Courant, E.D.; Garren, A.

    1985-10-01

    The phase shifting trombones considered up to now for SSC application consisted of sets of evenly spaced quadrupoles separated by drift spaces. One such trombone was placed between a dispersion suppressor and a crossing insertion, so that the trombone had zero dispersion. With such trombones, it is possible to change {beta}{sup *} at constant tune, or to change the tunes by several units without altering the cell phase advances in the arcs. An objection to the above type of phase trombone is that it adds to the circumference, since no bending is included. This objection may or may not be valid depending on the potential usefulness of the drift spaces in them. In this note the authors show an alternative trombone design in which dipoles are included between the quadrupoles as in the normal arc cells. Since these trombones have dispersion, they are placed at the ends of the arcs, to be followed in turn by the dispersion suppressors and crossing insertions.

  18. Historical Channel Adjustment and Estimates of Selected Hydraulic Values in the Lower Sabine River and Lower Brazos River Basins, Texas and Louisiana

    USGS Publications Warehouse

    Heitmuller, Franklin T.; Greene, Lauren E.

    2009-01-01

    The U.S. Geological Survey, in cooperation with the Texas Water Development Board, evaluated historical channel adjustment and estimated selected hydraulic values at U.S. Geological Survey streamflow-gaging stations in the lower Sabine River Basin in Texas and Louisiana and lower Brazos River Basin in Texas to support geomorphic assessments of the Texas Instream Flow Program. Channel attributes including cross-section geometry, slope, and planform change were evaluated to learn how each river's morphology changed over the years in response to natural and anthropogenic disturbances. Historical and contemporary cross-sectional channel geometries at several gaging stations on each river were compared, planform changes were assessed, and hydraulic values were estimated including mean flow velocity, bed shear stress, Froude numbers, and hydraulic depth. The primary sources of historical channel morphology information were U.S. Geological Survey hard-copy discharge-measurement field notes. Additional analyses were done using computations of selected flow hydraulics, comparisons of historical and contemporary aerial photographs, comparisons of historical and contemporary ground photographs, evaluations of how frequently stage-discharge rating curves were updated, reviews of stage-discharge relations for field measurements, and considerations of bridge and reservoir construction activities. Based on historical cross sections at three gaging stations downstream from Toledo Bend Reservoir, the lower Sabine River is relatively stable, but is subject to substantial temporary scour-and-fill processes during floods. Exceptions to this characterization of relative stability include an episode of channel aggradation at the Sabine River near Bon Wier, Texas, during the 1930s, and about 2 to 3 feet of channel incision at the Sabine River near Burkeville, Texas, since the late 1950s. The Brazos River, at gaging stations downstream from Waco, Texas, has adjusted to a combination of

  19. Seasonal variations in water quality of an oxbow lake in response to multiple short-time pulses of flooding (Jataí Ecological Station--Mogi-Guaçu River, Luiz Antonio, SP-Brazil).

    PubMed

    Krusche, A V; Mozeto, A A

    1999-01-01

    Mogi-Guaçu River is a six-order floodplain river in the upper Paraná River Basin, Southern Brazil. Its yearly discharge varies from a minimum of 100 m3.s-1 to a maximum of 600 m3.s-1. Diogo Lake is a shallow lake located at its floodplain within the Jataí Ecological Station (Luiz Antonio, São Paulo State) and is connected throughout the year to the river through a narrow and shallow channel. The main finding of this study is that the river hidrology controls the annual variations in lake hydrochemistry through a series of hydraulic effects related to oscillations in river discharge. Lake water quality is a resultant of differential contribution from local and regional watersheds. During the low water period, lake water quality is determined by inputs from Cafundó Creek, which drains the local watershed into the lake. Raising the river level during the rain season results in the damming of lake and culminates with the entrance of river waters into the plain. The geochemistry of waters in this system is determined by weathering of sandstones with basalt intrusions. Waters are acidic (river pH = 6.00 to 7.02 and stream-lake pH = 5.15 to 6.7) and dominant cations are Na+ and K+. Major anions are almost exclusively represented by bicarbonate and an unknown concentration of organic acid anions. The overall ionic load of these soft waters in the system is therefore very low.

  20. Concentrations and loads of cadmium, lead, and zinc measured near the peak of the 1999 snowmelt-runoff hydrographs for 42 water-quality stations, Coeur d'Alene River basin, Idaho

    USGS Publications Warehouse

    Woods, Paul F.

    2000-01-01

    The Coeur d’Alene River near Harrison transported 924 pounds of dissolved lead per day, of which 82.8 pounds came from the South Fork and 11.7 pounds from the North Fork. Only 10.2 percent of the load at Harrison was measured at the Pinehurst and Enaville stations; therefore, a substantial load of dissolved lead is being contributed downstream from the confluence of the North and South Forks.

  1. Beam bending via plasmonic lenses.

    PubMed

    Zhao, Yanhui; Lin, Sz-Chin Steven; Nawaz, Ahmad Ahsan; Kiraly, Brian; Hao, Qingzhen; Liu, Yanjun; Huang, Tony Jun

    2010-10-25

    We have designed and characterized three different types of plasmonic lenses that cannot only focus, but can also bend electromagnetic (EM) waves. The bending effect is achieved by constructing an asymmetric phase front caused by varying phase retardations in EM waves as they pass through a plasmonic lens. With an incident wave normal to the lens surface, light bends up to 8° off the axial direction. The optical wave propagation was numerically investigated using the finite-difference time-domain (FDTD) method. Simulation results show that the proposed plasmonic lenses allow effective beam bending under both normal and tilted incidence. With their relatively large bending range and capability to perform in the far field, the plamsonic lenses described in this article could be valuable in applications such as photonic communication and plasmonic circuits.

  2. Digital modeling of radioactive and chemical waste transport in the aquifer underlying the Snake River Plain at the National Reactor Testing Station, Idaho

    USGS Publications Warehouse

    Robertson, J.B.

    1974-01-01

    Industrial and low-level radioactive liquid wastes at the National Reactor Testing Station (NRTS) in Idaho have been disposed to the Snake River Plain aquifer since 1952. Monitoring studies have indicated that tritium and chloride have dispersed over a 15-square mile (39-square kilometer) area of the aquifer in low but detectable concentrations and have only migrated as far as 5 miles (8 kilometers) downgradient from discharge points. The movement of cationic waste solutes, particularly 90Sr and 137Cs, has been significantly retarded due to sorption phenomena, principally ion exchange. 137Cs has shown no detectable migration in the aquifer and 90Sr has migrated only about 1.5 miles (2 kilometers) from the Idaho Chemical Processing Plant (ICPP) discharge well, and is detectable over an area of only 1.5 square miles ( 4 square kilometers) of the aquifer. Digital modeling techniques have been applied successfully to the analysis of the complex waste-transport system by utilizing numerical solution of the coupled equations of groundwater motion and mass transport. The model includes the effects of convective transport, flow divergence, two-dimensional hydraulic dispersion, radioactive decay, and reversible linear sorption. The hydraulic phase of the model uses the iterative, alternating direction, implicit finite-difference scheme to solve the groundwater flow equations, while the waste-transport phase uses a modified method of characteristics to solve the solute transport equations simulated by the model. The modeling results indicate that hydraulic dispersion (especially transverse) is a much more significant influence than previously suggested by earlier studies. The model has been used to estimate future waste migration patterns for varied assumed hydrological and waste conditions up through the year 2000. The hydraulic effects of recharge from the Big Lost River have an important (but not predominant) influence on the simulated future migration patterns. For the

  3. 1. View looking south with Neshanic Station Bridge appearing underneath ...

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

    1. View looking south with Neshanic Station Bridge appearing underneath Lehigh Valley Railroad Bridge in foreground. Jet Lowe, photographer, 1983 - Neshanic Station Lenticular Truss Bridge, State Route 567, spanning South Branch of Raritan River, Neshanic Station, Somerset County, NJ

  4. A Dark Bend

    NASA Image and Video Library

    2016-09-05

    Saturn's rings appear to bend as they pass behind the planet's darkened limb due to refraction by Saturn's upper atmosphere. The effect is the same as that seen in an earlier Cassini view (see PIA20491), except this view looks toward the unlit face of the rings, while the earlier image viewed the rings' sunlit side. The difference in illumination brings out some noticeable differences. The A ring is much darker here, on the rings' unlit face, since its larger particles primarily reflect light back toward the sun (and away from Cassini's cameras in this view). The narrow F ring (at bottom), which was faint in the earlier image, appears brighter than all of the other rings here, thanks to the microscopic dust that is prevalent within that ring. Small dust tends to scatter light forward (meaning close to its original direction of travel), making it appear bright when backlit. (A similar effect has plagued many a driver with a dusty windshield when driving toward the sun.) This view looks toward the unilluminated side of the rings from about 19 degrees below the ring plane. The image was taken in red light with the Cassini spacecraft narrow-angle camera on July 24, 2016. The view was acquired at a distance of approximately 527,000 miles (848,000 kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 169 degrees. Image scale is 3 miles (5 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20497

  5. Evaluation of machine learning tools as a statistical downscaling tool: temperatures projections for multi-stations for Thames River Basin, Canada

    NASA Astrophysics Data System (ADS)

    Goyal, Manish Kumar; Burn, Donald H.; Ojha, C. S. P.

    2012-05-01

    Many impact studies require climate change information at a finer resolution than that provided by global climate models (GCMs). This paper investigates the performances of existing state-of-the-art rule induction and tree algorithms, namely single conjunctive rule learner, decision table, M5 model tree, and REPTree, and explores the impact of climate change on maximum and minimum temperatures (i.e., predictands) of 14 meteorological stations in the Upper Thames River Basin, Ontario, Canada. The data used for evaluation were large-scale predictor variables, extracted from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis dataset and the simulations from third generation Canadian coupled global climate model. Data for four grid points covering the study region were used for developing the downscaling model. M5 model tree algorithm was found to yield better performance among all other learning techniques explored in the present study. Hence, this technique was applied to project predictands generated from GCM using three scenarios (A1B, A2, and B1) for the periods (2046-2065 and 2081-2100). A simple multiplicative shift was used for correcting predictand values. The potential of the downscaling models in simulating predictands was evaluated, and downscaling results reveal that the proposed downscaling model can reproduce local daily predictands from large-scale weather variables. Trend of projected maximum and minimum temperatures was studied for historical as well as downscaled values using GCM and scenario uncertainty. There is likely an increasing trend for T max and T min for A1B, A2, and B1 scenarios while decreasing trend has been observed for B1 scenarios during 2081-2100.

  6. 33 CFR 334.540 - Banana River at the Eastern Range, 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Banana River at the Eastern Range... AND RESTRICTED AREA REGULATIONS § 334.540 Banana River at the Eastern Range, 45th Space Wing, Cape... navigable waters of the United States, as defined at 33 CFR part 329, within the Banana River contiguous to...

  7. 33 CFR 334.540 - Banana River at the Eastern Range, 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Banana River at the Eastern Range... AND RESTRICTED AREA REGULATIONS § 334.540 Banana River at the Eastern Range, 45th Space Wing, Cape... navigable waters of the United States, as defined at 33 CFR part 329, within the Banana River contiguous to...

  8. 33 CFR 334.540 - Banana River at the Eastern Range, 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Banana River at the Eastern Range... AND RESTRICTED AREA REGULATIONS § 334.540 Banana River at the Eastern Range, 45th Space Wing, Cape... navigable waters of the United States, as defined at 33 CFR part 329, within the Banana River contiguous to...

  9. 33 CFR 334.540 - Banana River at the Eastern Range, 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Banana River at the Eastern Range... AND RESTRICTED AREA REGULATIONS § 334.540 Banana River at the Eastern Range, 45th Space Wing, Cape... navigable waters of the United States, as defined at 33 CFR part 329, within the Banana River contiguous to...

  10. 33 CFR 334.540 - Banana River at the Eastern Range, 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Banana River at the Eastern Range... AND RESTRICTED AREA REGULATIONS § 334.540 Banana River at the Eastern Range, 45th Space Wing, Cape... navigable waters of the United States, as defined at 33 CFR part 329, within the Banana River contiguous to...

  11. Sheet Bending using Soft Tools

    NASA Astrophysics Data System (ADS)

    Sinke, J.

    2011-05-01

    Sheet bending is usually performed by air bending and V-die bending processes. Both processes apply rigid tools. These solid tools facilitate the generation of software for the numerical control of those processes. When the lower rigid die is replaced with a soft or rubber tool, the numerical control becomes much more difficult, since the soft tool deforms too. Compared to other bending processes the rubber backed bending process has some distinct advantages, like large radius-to-thickness ratios, applicability to materials with topcoats, well defined radii, and the feasibility of forming details (ridges, beads). These advantages may give the process exclusive benefits over conventional bending processes, not only for industries related to mechanical engineering and sheet metal forming, but also for other disciplines like Architecture and Industrial Design The largest disadvantage is that also the soft (rubber) tool deforms. Although the tool deformation is elastic and recovers after each process cycle, the applied force during bending is related to the deformation of the metal sheet and the deformation of the rubber. The deformation of the rubber interacts with the process but also with sheet parameters. This makes the numerical control of the process much more complicated. This paper presents a model for the bending of sheet materials using a rubber lower die. This model can be implemented in software in order to control the bending process numerically. The model itself is based on numerical and experimental research. In this research a number of variables related to the tooling and the material have been evaluated. The numerical part of the research was used to investigate the influence of the features of the soft lower tool, like the hardness and dimensions, and the influence of the sheet thickness, which also interacts with the soft tool deformation. The experimental research was focused on the relation between the machine control parameters and the most

  12. Space Station

    NASA Image and Video Library

    1991-01-01

    In 1982, the Space Station Task Force was formed, signaling the initiation of the Space Station Freedom Program, and eventually resulting in the Marshall Space Flight Center's responsibilities for Space Station Work Package 1.

  13. Bending Instabilities of Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Silvestre, N.; Camotim, D.

    This paper presents an investigation on the buckling behaviour of single-walled carbon nanotubes (NTs) under bending and unveils several aspects concerning the dependence of critical bending curvature on the NT length. The buckling results are obtained by means of non-linear shell finite element analyses using ABAQUS code. It is shown that eigenvalue analyses do not give a correct prediction of the critical curvature of NTs under bending. Conversely, incremental-iterative non-linear analyses provide a better approximation to the molecular dynamics results due to the progressive ovalization of the NT cross-section under bending. For short NTs, the limit curvature drops with the increasing length mostly due to the decreasing influence of end effects. For moderate to long tubes, the limit curvature remains practically constant and independent on the tube length. An approximate formula based on the Brazier expression is proposed to predict the limit curvature.

  14. A preliminary study on the effects of combined halogenation and thermal recirculation at a coal-fired generating station

    SciTech Connect

    Schnelle, R.C.; Strimple, P.D.

    1995-06-01

    East Bend Station is a single-unit, 650 megawatt, coal-fired generating station, located at Ohio River mile 510, near Rabbit Hash, Kentucky. Zebra mussel (Dreissena polymorpha) veligers were first detected at East Bend on 23 July 1992. Since then, the station has adopted a plan for preventing the settlement of zebra mussel veligers, by utilizing a combined halogenation and thermal recirculation treatment regime. A backflush pipeline was constructed, allowing 100% of the heated service water to be recycled through the intake well. During weekly treatments, the service water return to the river is valved out and water temperature is ramped up to between 31{degrees} - 35{degrees}C. HTH (calcium hypochlorite @65% available chlorine) is then slug-fed directly into the intake well. The temperature is maintained until the chlorine residual is below detectable limits. In addition to the weekly combined treatments, the service water system is also brominated for two hours, three times weekly, to 0.5 mg/1 TRO. Treatment efficacy is monitored, using a plexiglas biobox, seeded with adult mussels obtained from a substrate monitor attached to a barge cell and submerged to a depth of 3 meters. Preliminary results show both treatments to be ineffective for adult kill, however, it is believed that any newly-settle juveniles are being killed. Intake and equipment inspections during an upcoming unit outage will provide further verification. Additional testing, using various halogenation techniques, will be conducted during 1995.

  15. Bromide, Chloride, and Sulfate Concentrations and Loads at U.S. Geological Survey Streamflow-Gaging Stations 07331600 Red River at Denison Dam, 07335500 Red River at Arthur City, and 07336820 Red River near DeKalb, Texas, 2007-09

    USGS Publications Warehouse

    Baldys, Stanley; Churchill, Christopher J.; Mobley, Craig A.; Coffman, David K.

    2010-01-01

    The U.S. Geological Survey, in cooperation with the City of Dallas Water Utilities Division, did a study to characterize bromide, chloride, and sulfate concentrations and loads at three U.S. Geological Survey streamflow-gaging stations on the reach of the Red River from Denison Dam, which impounds Lake Texoma, to the U.S. Highway 259 bridge near DeKalb, Texas. Bromide, chloride, and sulfate concentrations and loads were computed for streamflow-gaging stations on the study reach of the Red River. Continuous streamflow and specific conductance data and discrete samples for bromide, chloride, sulfate, and specific conductance were collected at three main-stem streamflow-gaging stations on the Red River: 07331600 Red River at Denison Dam near Denison, Texas (Denison Dam gage), 07335500 Red River at Arthur City, Texas (Arthur City gage), and 07336820 Red River near DeKalb, Texas (DeKalb gage). At each of these streamflow-gaging stations, discrete water-quality data were collected during January 2007-February 2009; continuous water-quality data were collected during March 2007-February 2009. Two periods of high flow resulted from floods during the study; floods during June-July 2007 resulted in elevated flow during June-September 2007 and smaller floods during March-April 2008 resulted in elevated flow during March-April 2008. Bromide, chloride, and sulfate concentrations in samples collected at the three gages decreased downstream. Median bromide concentrations ranged from 0.32 milligram per liter at the Denison Dam gage to 0.19 milligram per liter at the DeKalb gage. Median chloride concentrations ranged from 176 milligrams per liter at the Denison Dam gage to 108 milligrams per liter at the DeKalb gage, less than the 300-milligrams per liter secondary maximum contaminant level established by the Texas Commission on Environmental Quality. Median sulfate concentrations ranged from 213 milligrams per liter at the Denison Dam gage to 117 milligrams per liter at the De

  16. Surface Meteorological Station - North Bend, OR (OTH) - Raw Data

    SciTech Connect

    Coleman, Tim

    2016-10-25

    A variety of instruments are used to measure various quantities related to meteorology, precipitation, and radiation near the Earth’s surface. Typically, a standard suite of instruments is deployed to monitor meteorological state variables.

  17. Carbon Burnout Project at Tampa Electric's Big Bend Station

    EPA Pesticide Factsheets

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  18. Passive, achromatic, nearly isochronous bending system

    DOEpatents

    Douglas, David R.; Yunn, Byung C.

    2004-05-18

    A particle beam bending system having a geometry that applies active bending only beyond the chord of the orbit for any momentum component. Using this bending configuration, all momentum components emerge dispersed in position only; all trajectories are parallel by construction. Combining a pair of such bends with reflective symmetry produces a bend cell that is, by construction, achromatic to all orders. By the particular choice of 45.degree. individual bends, a pair of such achromats can be used as the basis of a 180.degree. recirculation arc. Other rational fractions of a full 180.degree. bend serve equally well (e.g., 2 bends/cell.times.90.degree./bend.times.1 cell /arc; 2 bends/cell.times.30.degree./bend.times.3 cells/arc, etc), as do combinations of multiple bending numerologies (e.g., 2 bends/cell.times.22.5.degree./bend.times.2 cells+2 bends/cell.times.45.degree./bend.times.1 cell). By the choice of entry pole face rotation of the first magnet and exit pole face rotation of the second magnet (with a value to be determined from the particular beam stability requirements imposed by the choice of bending angle and beam properties to be used in any particular application), desirable focusing properties can be introduced and beam stability can be insured.

  19. Trace gases, aerosols and their interactions with synoptic weather: An overview of in-situ measurements at the SORPES Station in the western Yangtze River Delta, China

    NASA Astrophysics Data System (ADS)

    Ding, A.; Fu, C.; Yang, X.; Petaja, T.; Kerminen, V.; Kulmala, M. T.

    2013-12-01

    This work presents an overview of 1 yr measurements of ozone (O3) and fine particular matter (PM2.5) and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES), in the western part of the Yangtze River Delta (YRD) in eastern China. Ozone and PM2.5 showed strong seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and a formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1 yr period, suggesting a severe air pollution situation in this region. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the mid-YRD. North-YRD and the North China Plain are the main contributors to PM2.5pollution in this region. Case studies for typical O3 and PM2.5 episodes showed that synoptic weather played an important role in air pollution, especially for O3. Observation during the typical biomass burning seasons also shows clear air pollution - weather interactions. For the typical episode occurred on 10 June, 2012, the measurement suggest that the mixed agricultural burning plumes with fossil fuel combustion pollution resulted in a decrease of solar radiation by more than 70 %, of sensible heat flux over 85 %, a temperature drop by almost 10 K, and a change 10 of rainfall during daytime and nighttime. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving air quality in these areas through collaborative control measures among different administrative regions, and

  20. Trace gases, aerosols and their interactions with synoptic weather: An overview of in-situ measurements at the SORPES Station in the western Yangtze River Delta, China

    NASA Astrophysics Data System (ADS)

    Ding, A.; Fu, C.; Yang, X.; Petaja, T.; Kerminen, V.; Kulmala, M. T.

    2011-12-01

    This work presents an overview of 1 yr measurements of ozone (O3) and fine particular matter (PM2.5) and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES), in the western part of the Yangtze River Delta (YRD) in eastern China. Ozone and PM2.5 showed strong seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and a formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1 yr period, suggesting a severe air pollution situation in this region. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the mid-YRD. North-YRD and the North China Plain are the main contributors to PM2.5pollution in this region. Case studies for typical O3 and PM2.5 episodes showed that synoptic weather played an important role in air pollution, especially for O3. Observation during the typical biomass burning seasons also shows clear air pollution - weather interactions. For the typical episode occurred on 10 June, 2012, the measurement suggest that the mixed agricultural burning plumes with fossil fuel combustion pollution resulted in a decrease of solar radiation by more than 70 %, of sensible heat flux over 85 %, a temperature drop by almost 10 K, and a change 10 of rainfall during daytime and nighttime. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving air quality in these areas through collaborative control measures among different administrative regions, and

  1. Biomorphodynamic modelling of inner bank advance in migrating meander bends

    NASA Astrophysics Data System (ADS)

    Zen, Simone; Zolezzi, Guido; Toffolon, Marco; Gurnell, Angela M.

    2016-07-01

    We propose a bio-morphodynamic model at bend cross-sectional scale for the lateral migration of river meander bends, where the two banks can migrate separately as a result of the mutual interaction between river flow, sediments and riparian vegetation, particularly at the interface between the permanently wet channel and the advancing floodplain. The model combines a non-linear analytical model for the morphodynamic evolution of the channel bed, a quasi-1D model to account for flow unsteadiness, and an ecological model describing riparian vegetation dynamics. Simplified closures are included to estimate the feedbacks among vegetation, hydrodynamics and sediment transport, which affect the morphology of the river-floodplain system. Model tests reveal the fundamental role of riparian plants in generating bio-morphological patterns at the advancing floodplain margin. Importantly, they provide insight into the biophysical controls of the 'bar push' mechanism and into its role in the lateral migration of meander bends and in the temporal variations of the active channel width.

  2. Predicting the impact of riverbed excavation on the buried depth of groundwater table and capillary water zone in the river banks-taking Xinfeng hydropower station as an example

    NASA Astrophysics Data System (ADS)

    Shi, Jie; Lan, Jun-Kang

    2017-06-01

    In order to obtain a larger water level drop for power generation, Xinfeng hydropower station proposed to dig 0∼3m depth under the riverbed of downstream. This will affect the burial depth of the groundwater level and capillary water zone on both sides of the river and the nearby resident life and agriculture production. In this study, a three-dimensional groundwater numerical model was set using GMS software to predict the flow field changes after the downstream of riverbed was deepen in Xinfeng hydropower station. Simulation results showed that groundwater level near the bank will greatly decline, affecting water consumption of local residents. Because of the local developed canal system and abundant irrigation water amount, riverbed excavation barely affects agriculture production when increasing the irrigation water volume and frequency.

  3. Bending fracture in carbon nanotubes.

    PubMed

    Kuo, Wen-Shyong; Lu, Hsin-Fang

    2008-12-10

    A novel approach was adopted to incur bending fracture in carbon nanotubes (CNTs). Expanded graphite (EG) was made by intercalating and exfoliating natural graphite flakes. The EG was deposited with nickel particles, from which CNTs were grown by chemical vapor deposition. The CNTs were tip-grown, and their roots were fixed on the EG flakes. The EG flakes were compressed, and many CNTs on the surface were fragmented due to the compression-induced bending. Two major modes of the bending fracture were observed: cone-shaped and shear-cut. High-resolution scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the crack growth within the graphene layers. The bending fracture is characterized by two-region crack growth. An opening crack first appears around the outer-tube due to the bending-induced tensile stress. The crack then branches to grow along an inclined direction toward the inner-tube due to the presence of the shear stress in between graphene layers. An inner-tube pullout with inclined side surface is formed. The onset and development of the crack in these two regions are discussed.

  4. Regression Equations for Estimating Concentrations of Selected Water-Quality Constituents for Selected Gaging Stations in the Red River of the North Basin, North Dakota, Minnesota, and South Dakota

    USGS Publications Warehouse

    Williams-Sether, Tara

    2004-01-01

    The Dakota Water Resources Act, passed by the U.S. Congress on December 15, 2000, authorized the Secretary of the Interior to conduct a comprehensive study of future water-quantity and quality needs of the Red River of the North Basin in North Dakota and possible options to meet those water needs. Previous Red River of the North Basin studies conducted by the Bureau of Reclamation used streamflow and water-quality data bases developed by the U.S. Geological Survey that included data for 1931-84. As a result of the recent congressional authorization and results of previous studies by the Bureau of Reclamation, redevelopment of the streamflow and water-quality data bases with current data through 1999 are needed in order to evaluate and predict the water-quantity and quality effects within the Red River of the North Basin. This report provides updated statistical summaries of selected water-quality constituents and streamflow and the regression relations between them. Available data for 1931-99 were used to develop regression equations between 5 selected water-quality constituents and streamflow for 38 gaging stations in the Red River of the North Basin. The water-quality constituents that were regressed against streamflow were hardness (as CaCO3), sodium, chloride, sulfate, and dissolved solids. Statistical summaries of the selected water-quality constituents and streamflow for the gaging stations used in the regression equations development and the applications and limitations of the regression equations are presented in this report.

  5. Bending rules for animal propulsion.

    PubMed

    Lucas, Kelsey N; Johnson, Nathan; Beaulieu, Wesley T; Cathcart, Eric; Tirrell, Gregory; Colin, Sean P; Gemmell, Brad J; Dabiri, John O; Costello, John H

    2014-01-01

    Animal propulsors such as wings and fins bend during motion and these bending patterns are believed to contribute to the high efficiency of animal movements compared with those of man-made designs. However, efforts to implement flexible designs have been met with contradictory performance results. Consequently, there is no clear understanding of the role played by propulsor flexibility or, more fundamentally, how flexible propulsors should be designed for optimal performance. Here we demonstrate that during steady-state motion by a wide range of animals, from fruit flies to humpback whales, operating in either air or water, natural propulsors bend in similar ways within a highly predictable range of characteristic motions. By providing empirical design criteria derived from natural propulsors that have convergently arrived at a limited design space, these results provide a new framework from which to understand and design flexible propulsors.

  6. Method for uniformly bending conduits

    DOEpatents

    Dekanich, S.J.

    1984-04-27

    The present invention is directed to a method for bending metal tubing through various radii while maintaining uniform cross section of the tubing. The present invention is practical by filling the tubing to a sufficient level with water, freezing the water to ice and bending the ice-filled tubing in a cooled die to the desired radius. The use of the ice as a filler material provides uniform cross-sectional bends of the tubing and upon removal of the ice provides an uncontaminated interior of the tubing which will enable it to be used in its intended application without encountering residual contaminants in the tubing due to the presence of the filler material.

  7. Bending Rules in Graphene Kirigami

    NASA Astrophysics Data System (ADS)

    Grosso, Bastien F.; Mele, E. J.

    2015-11-01

    The three-dimensional shapes of graphene sheets produced by nanoscale cut-and-join kirigami are studied by combining large-scale atomistic simulations with continuum elastic modeling. Lattice segments are selectively removed from a graphene sheet, and the structure is allowed to close by relaxing in the third dimension. The surface relaxation is limited by a nonzero bending modulus which produces a smoothly modulated landscape instead of the ridge-and-plateau motif found in macroscopic lattice kirigami. The resulting surface shapes and their interactions are well described by a new set of microscopic kirigami rules that resolve the competition between bending and stretching energies.

  8. Bending Rules in Graphene Kirigami.

    PubMed

    Grosso, Bastien F; Mele, E J

    2015-11-06

    The three-dimensional shapes of graphene sheets produced by nanoscale cut-and-join kirigami are studied by combining large-scale atomistic simulations with continuum elastic modeling. Lattice segments are selectively removed from a graphene sheet, and the structure is allowed to close by relaxing in the third dimension. The surface relaxation is limited by a nonzero bending modulus which produces a smoothly modulated landscape instead of the ridge-and-plateau motif found in macroscopic lattice kirigami. The resulting surface shapes and their interactions are well described by a new set of microscopic kirigami rules that resolve the competition between bending and stretching energies.

  9. Bending of floating flexible legs

    NASA Astrophysics Data System (ADS)

    Park, Kun Joong; Kim, Ho-Young

    When long thin flexible solid objects, such as the legs of water striders, disposable spoons and human hairs, are pressed against a liquid surface, they bend due to interfacial and hydrostatic forces. To understand the phenomenon, we study the bending of a sheet touching the liquid surface at an angle while clamped at the other end, to find its deflection and the load that the sheet can support before sinking. The theoretically predicted shapes of the sheet and the meniscus match well with experiments. Our theory shows that flexible sheets can support more load than rigid ones before sinking when the sheets are highly hydrophobic.

  10. Compaction managed mirror bend achromat

    DOEpatents

    Douglas, David [Yorktown, VA

    2005-10-18

    A method for controlling the momentum compaction in a beam of charged particles. The method includes a compaction-managed mirror bend achromat (CMMBA) that provides a beamline design that retains the large momentum acceptance of a conventional mirror bend achromat. The CMMBA also provides the ability to tailor the system momentum compaction spectrum as desired for specific applications. The CMMBA enables magnetostatic management of the longitudinal phase space in Energy Recovery Linacs (ERLs) thereby alleviating the need for harmonic linearization of the RF waveform.

  11. 2014 land cover land use horseshoe bend

    USGS Publications Warehouse

    Hanson, Jenny L.; Hoy, Erin E.; Robinson, Larry R.

    2016-01-01

    This collection of conservation areas consists of the floodplain of the combined streams of the Iowa River and the Cedar River. The study area begins just southeast of Wapello, IA, and continues southeast until the Horseshoe Bend Division, Port Louisa NWR. The area is currently managed to maintain meadow or grassland habitat which requires intensive management due to vegetative succession. In addition, this floodplain area contains a high proportion of managed lands and private lands in the Wetland Reserve Program and is a high priority area for cooperative conservation actions. This project provides a late-summer baseline vegetation inventory to assess future management actions in an adaptive process. Changes in levees, in addition to increased water flows and flood events due to climate change and land use practices, make restoration of floodplain processes more complex. Predictive models could help determine more efficient and effective restoration and management techniques. Successful GIS tools developed for this project would be applicable to other floodplain refuges and conservation areas.

  12. Design and installation of continuous flow and water qualitymonitoring stations to improve water quality forecasting in the lower SanJoaquin River

    SciTech Connect

    Quinn, Nigel W.T.

    2007-01-20

    This project deliverable describes a number ofstate-of-the-art, telemetered, flow and water quality monitoring stationsthat were designed, instrumented and installed in cooperation with localirrigation water districts to improve water quality simulation models ofthe lower San Joaquin River, California. This work supports amulti-disciplinary, multi-agency research endeavor to develop ascience-based Total Maximum Daily Load for dissolved oxygen in the SanJoaquin River and Stockton Deep Water Ship Channel.

  13. International Space Station (ISS)

    NASA Image and Video Library

    2002-06-18

    This is a photo of the Hayman Fire burning in the foothills southwest of Denver, Colorado, as viewed by an Expedition Five crewmember aboard the International Space Station (ISS). Astronauts use a variety of lenses and look angles as their orbits pass over the wildfires to document the long-distance movements of smoke from the fires as well as details of the burning areas. In this view, Littleton, Chatfield Lake, and the Arkansas River are all visible.

  14. Hormonal regulation of gravitropic bending

    NASA Astrophysics Data System (ADS)

    Hu, X.; Cui, D.; Xu, X.; Hu, L.; Cai, W.

    Gravitropic bending is an important subject in the research of plant Recent data support the basics of the Cholodny-Went hypothesis indicating that differential growth in gravitropism is due to redistribution of auxin to the lower sides of gravistimulated roots but little is known regarding the molecular details of such effects So we carried a series of work surround the signals induced by auxin end center We found the endogenous signaling molecules nitric oxide NO and cGMP mediate responses to gravistimulation in primary roots of soybean Glycine max Horizontal orientation of soybean roots caused the accumulation of both NO and cGMP in the primary root tip Fluorescence confocal microcopy revealed that the accumulation of NO was asymmetric with NO concentrating in the lower side of the root Auxin induced NO accumulation in root protoplasts and asymmetric NO accumulation in root tips Gravistimulation NO and auxin also induced the accumulation of cGMP a response inhibited by removal of NO or by inhibitors of guanylyl cyclase compounds that also reduced gravitropic bending Asymmetric NO accumulation and gravitropic bending were both inhibited by an auxin transport inhibitor and the inhibition of bending was overcome by treatment with NO or 8-bromo-cGMP a cell-permeable analog of cGMP These data indicate that auxin-induced NO and cGMP mediate gravitropic curvature in soybean roots From Hu et al Plant Physiol 2005 137 663-670 The asymmetric distribution of auxin plays a fundamental role in plant gravitropic bending

  15. Annual Peak-Flow Frequency Characteristics and (or) Peak Dam-Pool-Elevation Frequency Characteristics of Dry Dams and Selected Streamflow-Gaging Stations in the Great Miami River Basin, Ohio

    USGS Publications Warehouse

    Koltun, G.F.

    2009-01-01

    This report describes the results of a study to determine frequency characteristics of postregulation annual peak flows at streamflow-gaging stations at or near the Lockington, Taylorsville, Englewood, Huffman, and Germantown dry dams in the Miami Conservancy District flood-protection system (southwestern Ohio) and five other streamflow-gaging stations in the Great Miami River Basin further downstream from one or more of the dams. In addition, this report describes frequency characteristics of annual peak elevations of the dry-dam pools. In most cases, log-Pearson Type III distributions were fit to postregulation annual peak-flow values through 2007 (the most recent year of published peak-flow values at the time of this analysis) and annual peak dam-pool storage values for the period 1922-2008 to determine peaks with recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years. For one streamflow-gaging station (03272100) with a short period of record, frequency characteristics were estimated by means of a process involving interpolation of peak-flow yields determined for an upstream and downstream gage. Once storages had been estimated for the various recurrence intervals, corresponding dam-pool elevations were determined from elevation-storage ratings provided by the Miami Conservancy District.

  16. Geomorphic Effects of Engineered Log Jams in River Restoration, Middle Fork John Day River

    NASA Astrophysics Data System (ADS)

    Duffin, J.; McDowell, P. F.

    2014-12-01

    The Middle Fork of the John Day River (MFJD) Intensively Monitored Watershed in eastern Oregon is a multi-phase restoration implementation and monitoring project. MFJD is a tributary to the Colombia and is part of one of the longest free flowing rivers systems in the continental United States. It is a gravel and cobble bed river with a drainage area of 2,100 km2. The river has endured extensive channel and floodplain degradation from years of channel alteration and straightening due to human influences including dredge mining, ranching, and farming. As part of the river restoration project on the MFJD, engineered log jams have been constructed to address many of the restoration goals including creating scour pools, inhibiting bank erosion, creating and maintaining a sinuous river planform, and increasing complexity of fish habitat. There is a need for more detailed understanding on ELJ channel morphologic effects and how site-specific characteristics and differences in log jam infrastructure interact to create the in-channel features over timescales longer than a few years. This study uses detailed channel bed topographic surveys collected either with a total station or RTK-GPS technology. Geomorphic change detection techniques are utilized to monitor topographic change under and around the 26 log structures in two different river reaches over a six to seven year period The log structures are often associated with deepening of pools as desired, but also some structures show sedimentation under the structure. Differences in the patterns will be assessed based on the design, location, and specific characteristics of the log structures; variables include number and placement of logs, volume of structure, location on meander bend, and sediment sizes.

  17. Bend ductility of tungsten heavy alloys

    SciTech Connect

    Gurwell, W.E.; Garnich, M.R.; Dudder, G.B.; Lavender, C.A.

    1992-11-01

    A bend ductility test is used to indicate the formability of tungsten heavy alloys sheet. The primary test bends a notchless Charpy impact specimen to a bend angle of approximately 100C. This can be augmented by a bend-completion test. Finite element modeling as well as strain-gaged bend specimens elucidate the strain distribution in the specimen as a function of material thickness and bend angle. The bend ductilities of 70%W, 807.W and 90%W alloys are characterized. As expected, decreasing thickness or tungsten content enhances bend ductility. Oxidation is not detrimental; therefore, controlled atmosphere is not required for cooling. The potentially detrimental effects of mechanical working (e.g., rolling, roller-leveling, grit blasting, and peening) and machining (e.g., cutting and sanding) are illustrated.

  18. Bend ductility of tungsten heavy alloys

    SciTech Connect

    Gurwell, W.E.; Garnich, M.R.; Dudder, G.B.; Lavender, C.A.

    1992-11-01

    A bend ductility test is used to indicate the formability of tungsten heavy alloys sheet. The primary test bends a notchless Charpy impact specimen to a bend angle of approximately 100C. This can be augmented by a bend-completion test. Finite element modeling as well as strain-gaged bend specimens elucidate the strain distribution in the specimen as a function of material thickness and bend angle. The bend ductilities of 70%W, 807.W and 90%W alloys are characterized. As expected, decreasing thickness or tungsten content enhances bend ductility. Oxidation is not detrimental; therefore, controlled atmosphere is not required for cooling. The potentially detrimental effects of mechanical working (e.g., rolling, roller-leveling, grit blasting, and peening) and machining (e.g., cutting and sanding) are illustrated.

  19. Stream-Flow Measurements at Selected Gaging Stations in the Iowa and Des Moines River Basins and Development of Stage-Discharge Relationships

    DTIC Science & Technology

    2003-07-01

    34 - Long 94°07󈧦" • Drainage Area = 2167 sq. mi. • River Mile = N/A • Location of Gage = On left bank 15 ft downstream from bridge on State Highway...17825 18041 18258 18477 18698 18920 2167 20 19143 19368 19594 19822 20052 20283 20515 20749 20985 21222 2317 21 21460 PROI4 - NORTH RACCOON RIVER NEAR...5230 5354 5480 5608 5739 1228 22 5873 6009 6147 6288 6431 6577 6726 6878 7032 7189 1476 23 7348 7511 7676 7845 8016 8190 8368 8548 8731 8918 1759 24

  20. Bending loss of terahertz pipe waveguides.

    PubMed

    Lu, Jen-Tang; Hsueh, Yu-Chun; Huang, Yu-Ru; Hwang, Yuh-Jing; Sun, Chi-Kuang

    2010-12-06

    We present an experimental study on the bending loss of terahertz (THz) pipe waveguide. Bending loss of pipe waveguides is investigated for various frequencies, polarizations, core diameters, cladding thicknesses, and cladding materials. Our results indicate that the pipe waveguides with lower guiding loss suffer lower bending loss due to stronger mode confinement. The unexpected low bending loss in the investigated simple leaky waveguide structure promises variety of flexible applications.

  1. Acoustic characteristics of circular bends in pipes

    NASA Astrophysics Data System (ADS)

    Firth, D.; Fahy, F. J.

    1984-11-01

    The acoustic properties of circular bends in pipework systems are investigated by calculation of the mode shapes and propagation constants of the acoustic modes of the bend, the torus modes, and by evaluation of the transmission and reflection coefficients at a bend in an otherwise infinite straight pipe. The coefficients for the first three cylinder and torus modes are plotted against frequency for the case of a plane wave incident upon a 90° bend. The pipe walls are assumed to be rigid.

  2. Improved Method Of Bending Concentric Pipes

    NASA Technical Reports Server (NTRS)

    Schroeder, James E.

    1995-01-01

    Proposed method for bending two concentric pipes simultaneously while maintaining void between them replaces present tedious, messy, and labor-intensive method. Array of rubber tubes inserted in gap between concentric pipes. Tubes then inflated with relatively incompressible liquid to fill gap. Enables bending to be done faster and more cleanly, and amenable to automation of significant portion of bending process on computer numerically controlled (CNC) tube-bending machinery.

  3. Steam-bending properties of southern pine

    Treesearch

    Truett J. Lemoine; Peter Koch

    1971-01-01

    Southern pine wood can be successfully steam-bent if the bending jig incorporates a flexible metal bending strap together with a mechanism to apply a uniform end compression load during the bending operation. With clear, 1/2- and 1-inch-thick southern pine at 17-percent moisture content, highest bending rating where obtained with fast-grown, vertical-grain, low-density...

  4. Space Station

    NASA Image and Video Library

    1972-01-01

    This is an artist's concept of a modular space station. In 1970 the Marshall Space Flight Center arnounced the completion of a study concerning a modular space station that could be launched by the planned-for reusable Space Shuttle. The study envisioned a space station composed of cylindrical sections 14 feet in diameter and of varying lengths joined to form any one of a number of possible shapes. The sections were restricted to 14 feet in diameter and 58 feet in length to be consistent with a shuttle cargo bay size of 15 by 60 feet. Center officials said that the first elements of the space station could be in orbit by about 1978 and could be manned by three or six men. This would be an interim space station with sections that could be added later to form a full 12-man station by the early 1980s.

  5. Space station

    NASA Technical Reports Server (NTRS)

    Stewart, Donald F.; Hayes, Judith

    1989-01-01

    The history of American space flight indicates that a space station is the next logical step in the scientific pursuit of greater knowledge of the universe. The Space Station and its complement of space vehicles, developed by NASA, will add new dimensions to an already extensive space program in the United States. The Space Station offers extraordinary benefits for a comparatively modest investment (currently estimated at one-ninth the cost of the Apollo Program). The station will provide a permanent multipurpose facility in orbit necessary for the expansion of space science and technology. It will enable significant advancements in life sciences research, satellite communications, astronomy, and materials processing. Eventually, the station will function in support of the commercialization and industrialization of space. Also, as a prerequisite to manned interplanetary exploration, the long-duration space flights typical of Space Station missions will provide the essential life sciences research to allow progressively longer human staytime in space.

  6. FFAG lattice without opposite bends

    NASA Astrophysics Data System (ADS)

    Trbojevic, Dejan; Courant, Ernest D.; Garren, Al

    2000-08-01

    A future "neutrino factory" or Muon Collider requires fast muon acceleration before the storage ring. Several alternatives for fast muon acceleration have previously been considered. One of them is the FFAG (Fixed Field Alternating Gradient) synchrotron. The FFAG concept was developed in 1952 by K. R. Symon (ref. 1). The advantages of this design are the fixed magnetic field, large range of particle energy, simple RF; power supplies are simple, and there is no transition energy. But a drawback is that reverse bending magnets are included in the configuration; this increases the size and cost of the ring. Recently some modified FFAG lattice designs have been described where the amount of opposite bending was significantly reduced (ref. 2, ref. 3).

  7. Space Station

    NASA Technical Reports Server (NTRS)

    Anderton, D. A.

    1985-01-01

    The official start of a bold new space program, essential to maintain the United States' leadership in space was signaled by a Presidential directive to move aggressively again into space by proceeding with the development of a space station. Development concepts for a permanently manned space station are discussed. Reasons for establishing an inhabited space station are given. Cost estimates and timetables are also cited.

  8. Ecological evaluation of proposed dredged material from the Point Frazer Bend Reach, Winyah Bay, South Carolina

    SciTech Connect

    Gardiner, W.W.; Ward, J.A.; Word, J.Q.

    1995-02-01

    The port of Georgetown, South Carolina, is served by navigational channels within Winyah Bay and the lower Sampit River. Dredging is required to maintain these waterways and to facilitate normal shipping traffic. Prior to dredging, ecological evaluations must be conducted to determine the suitability of the proposed dredged material for open-ocean disposal. These evaluations are to be performed under Section 103 of the Marine Protection, Research, and, Sanctuaries Act of 1972 (MPRSA), following the testing protocols presented in Evaluation of Dredged Material Proposed for Ocean Disposal Testing Manual, hereafter referred to as the 1991 Implementation Manual. The Charleston Intensive Project is a reevaluation of sediments collected from two stations (IH-2 and IH-3) in the Frazier Point Bend reach of the Winyah Bay channel. Reference sediment was also collected from site IH-R2, just south of Hare Island. The results of physical/chemical analyses indicated that some contaminants of concern were present in test treatments representing dredged material when compared with the reference treatment IH-R2. The results of this study indicate that, based on the acute toxicity and chemical analyses, dredged material represented by these test treatments is suitable for open-ocean disposal.

  9. 50. Stream gaging station in steelpipe well and shelter, looking ...

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

    50. Stream gaging station in steel-pipe well and shelter, looking west. Photo by Robin Lee Tedder, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  10. 49. View of unlined canal near inline stream gaging station, ...

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

    49. View of unlined canal near in-line stream gaging station, looking west. Photo by Robin Lee Tedder, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  11. Rear of REPLACEMENT MODEL single chair from mid station. Tower ...

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

    Rear of REPLACEMENT MODEL single chair from mid station. Tower 13 in background, LOOKing northeast. - Mad River Glen, Single Chair Ski Lift, 62 Mad River Glen Resort Road, Fayston, Washington County, VT

  12. 1. Photocopied from Photo 1645, Wheelon Station Folder #1, Engineering ...

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

    1. Photocopied from Photo 1645, Wheelon Station Folder #1, Engineering Department, Utah Power & Light Co., Salt Lake City, Utah. UTAH SUGAR CO.'S DAM -- BEAR RIVER CANYON. - Irrigation Diversion Canal, Bear River, Fielding, Box Elder County, UT

  13. 7. STATION 'L' FROM THE WEST BANK OF THE WILLAMETTE ...

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

    7. STATION 'L' FROM THE WEST BANK OF THE WILLAMETTE RIVER LOOKING EAST, SCREEN HOUSES AND TURBINE BUILDINGS IN FOREGROUND - Portland General Electric Company, Station "L", 1841 Southeast Water Street, Portland, Multnomah County, OR

  14. 5. VIEW OF STATION 'L' FROM WEST BANK OF THE ...

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

    5. VIEW OF STATION 'L' FROM WEST BANK OF THE WILLAMETTE RIVER, SCREEN HOUSES AND TURBINE BUILDINGS IN FOREGROUND - Portland General Electric Company, Station "L", 1841 Southeast Water Street, Portland, Multnomah County, OR

  15. Geomorpho-tectonic evolution of the Jamaican restraining bend

    NASA Astrophysics Data System (ADS)

    Domínguez-González, Leomaris; Andreani, Louis; Stanek, Klaus P.; Gloaguen, Richard

    2015-01-01

    This work applies recent advances in tectonic geomorphology in order to understand the geomorphic evolution of the Jamaican restraining bend located along the Caribbean-Gonâve-North American plate boundary. We propose a classification of landscapes according to their erosional stages. The approach is mainly based on the combination of two DEM-based geomorphic indices: the hypsometric integral which highlights elevated surfaces, and the surface roughness which increases when the relief is incised by the drainage network. River longitudinal profiles were also analyzed as the drainage network responds quickly to base-level change triggered by external forcing such as tectonics. Anomalies in river profiles (knickpoints and convex segments) were mapped using stream length-gradient (SL) and normalized steepness (ksn) indices. The results provide new insights for understanding the complex evolution of the Jamaican restraining bend. Three main morphotectonic regions were identified in Jamaica: (1) the Blue Mountain-Wagwater unit located at the eastern tip of the island, (2) the Jamaican highlands plateau which covers most of the northern and central areas and (3) the tilted block province located along the southern part of Jamaica. Each region has a specific morphological signature which marks a different stage in the Late Miocene to present evolution of the Jamaican restraining bend. The evolution of the bend is mainly associated with the western propagation of major E-trending strike-slip faults and NW-trending thrusts. In the western and central parts of Jamaica the present-day motion between the Caribbean plate and the Gonâve microplate is broadly distributed along several structures, while in the easternmost part of the island this motion seems to be almost completely accommodated along the Blue Mountain range and the Plantain-Garden Fault.

  16. 14. PROJECT PLAN, INTAKE PIER, RAW WATER CONDUITS, PUMPING STATION ...

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

    14. PROJECT PLAN, INTAKE PIER, RAW WATER CONDUITS, PUMPING STATION FORCE MAINS, TREATED WATER PIPELINES, AND FILTRATION PLANT, SHEET 1 OF 117, 1920. - Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA

  17. Space Station

    NASA Image and Video Library

    1952-01-01

    This is a von Braun 1952 space station concept. In a 1952 series of articles written in Collier's, Dr. Wernher von Braun, then Technical Director of the Army Ordnance Guided Missiles Development Group at Redstone Arsenal, wrote of a large wheel-like space station in a 1,075-mile orbit. This station, made of flexible nylon, would be carried into space by a fully reusable three-stage launch vehicle. Once in space, the station's collapsible nylon body would be inflated much like an automobile tire. The 250-foot-wide wheel would rotate to provide artificial gravity, an important consideration at the time because little was known about the effects of prolonged zero-gravity on humans. Von Braun's wheel was slated for a number of important missions: a way station for space exploration, a meteorological observatory and a navigation aid. This concept was illustrated by artist Chesley Bonestell.

  18. Merrimack River Watershed Communities

    EPA Pesticide Factsheets

    Listing of all communities included in each of the hydrologic unit code (HUC) 8, 10, and 12 boundaries for the Merrimack River Watershed and city locations for the EPA water quality monitoring stations.

  19. Final Environmental Assessment, Construct Antenna Parts Storage Facility, Upgrade Perimeter Security Fence and Demolish Camera Shed, Red River Air Force Space Surveillance Station (AFSSS), Lewisville, Arkansas

    DTIC Science & Technology

    2012-11-01

    Substandard”). Condition Code 3 means this facility cannot be raised to meet Class A standard to house the function for which it is currently...and energy goals; • Have sufficient space to house all necessary parts and equipment; • Enhance security for the space surveillance system program...within the Red River AFSSS (NAVFAC, 2003). Radon Radon testing was performed in April 1999 and results indicate radon levels below the threshold

  20. Priest River Experimental Forest (Idaho)

    Treesearch

    Russell T. Graham; Theresa B. Jain

    2004-01-01

    Priest River Experimental Forest was among the first experimental forests: it was set aside as a forestry research center in September 1911. The forest served as the headquarters for the Priest River Experiment Station until 1930 when it was incorporated into the Northern Rocky Mountain Forest and Range Experiment Station, which, in turn, joined the Intermountain...

  1. Space Station

    NASA Image and Video Library

    1969-01-01

    This picture illustrates a concept of a 33-Foot-Diameter Space Station Leading to a Space Base. In-house work of the Marshall Space Flight Center, as well as a Phase B contract with the McDornel Douglas Astronautics Company, resulted in a preliminary design for a space station in 1969 and l970. The Marshall-McDonnel Douglas approach envisioned the use of two common modules as the core configuration of a 12-man space station. Each common module was 33 feet in diameter and 40 feet in length and provided the building blocks, not only for the space station, but also for a 50-man space base. Coupled together, the two modules would form a four-deck facility: two decks for laboratories and two decks for operations and living quarters. Zero-gravity would be the normal mode of operation, although the station would have an artificial gravity capability. This general-purpose orbital facility was to provide wide-ranging research capabilities. The design of the facility was driven by the need to accommodate a broad spectrum of activities in support of astronomy, astrophysics, aerospace medicine, biology, materials processing, space physics, and space manufacturing. To serve the needs of Earth observations, the station was to be placed in a 242-nautical-mile orbit at a 55-degree inclination. An Intermediate-21 vehicle (comprised of Saturn S-IC and S-II stages) would have launched the station in 1977.

  2. Comparing the Planform Morphologies of a Freely Meandering Channel and the Bedrock- Controlled South River, VA.

    NASA Astrophysics Data System (ADS)

    Narinesingh, P.; Pizzuto, J.

    2008-12-01

    The planforms of the lithologically controlled South River, VA, and the freely meandering Teklanika River, AK were investigated using two statistical methods as well as fractal and spectral analyses. The lithologic controls along the South River include riverbanks consisting of pre-Holocene terraces and alluvial fans, and highly resistant bedrock that frequently crops out both in the bed and along the banks. A statistical analysis of bends composed of single arcs shows that the average radius of curvature is six times greater and the average bend length is 25 percent smaller for the South River relative to the meandering river, indicating that lithologically controlled bends are less curved and shorter than freely-formed meander bends. Fractal analysis reveals that the meandering river displays a smaller range in length scales than the South River, which exhibits a wider range in length scales that reflect a wider distribution of bend sizes. The method of Lancaster and Bras, (2002), which identifies bends of different complexity, indicates that the meandering river displays bends composed of single arcs, complex arcs and multiple complex arcs. Unlike the freely meandering Teklanika River, the lithologically controlled South River does not display bends composed of multiple complex arcs, though bends composed of single and complex arcs are common. Spectral analysis reveals that the meandering river's pattern is composed of a relatively narrow range of dominant wavelengths with the most prominent wavelength being the longest, while the lithologically controlled river displays dominant wavelengths over a relatively wide range and the most prominent wavelength is not the longest. This analysis demonstrates that lithological controls increase the range of bend lengths, increase radii of curvature, simplify bend shapes, and increase the distribution of wavelengths of sinuous rivers.

  3. WHERE THE GRANULAR FLOWS BEND

    SciTech Connect

    Khomenko, E.; Martinez Pillet, V.; Bonet, J. A.; Del Toro Iniesta, J. C.; Domingo, V.; Schmidt, W.; Knoelker, M.

    2010-11-10

    Based on IMaX/SUNRISE data, we report on a previously undetected phenomenon in solar granulation. We show that in a very narrow region separating granules and intergranular lanes, the spectral line width of the Fe I 5250.2 A line becomes extremely small. We offer an explanation of this observation with the help of magneto-convection simulations. These regions with extremely small line widths correspond to the places where the granular flows bend from upflow in granules to downflow in intergranular lanes. We show that the resolution and image stability achieved by IMaX/SUNRISE are important requisites to detect this interesting phenomenon.

  4. Space Station

    NASA Image and Video Library

    1991-01-01

    This artist's concept depicts the Space Station Freedom as it would look orbiting the Earth, illustrated by Marshall Space Flight Center artist, Tom Buzbee. Scheduled to be completed in late 1999, this smaller configuration of the Space Station featured a horizontal truss structure that supported U.S., European, and Japanese Laboratory Modules; the U.S. Habitation Module; and three sets of solar arrays. The Space Station Freedom was an international, permanently marned, orbiting base to be assembled in orbit by a series of Space Shuttle missions that were to begin in the mid-1990's.

  5. Space Station

    NASA Image and Video Library

    1991-01-01

    This artist's concept depicts the Space Station Freedom as it would look orbiting the Earth; illustrated by Marshall Space Flight Center artist, Tom Buzbee. Scheduled to be completed in late 1999, this smaller configuration of the Space Station features a horizontal truss structure that supported U.S., European, and Japanese Laboratory Modules; the U.S. Habitation Module; and three sets of solar arrays. The Space Station Freedom was an international, permanently marned, orbiting base to be assembled in orbit by a series of Space Shuttle missions that were to begin in the mid-1990's.

  6. Surface-water-quality assessment of the upper Illinois River Basin in Illinois, Indiana, and Wisconsin; fixed-station network and selected water-quality data for April 1987-September 1990

    USGS Publications Warehouse

    Sullivan, Daniel J.; Blanchard, Stephen F.

    1994-01-01

    This report describes and presents the sampling design, methods, quality assurance methods and results, and information on how to obtain data collected at eight fixed stations in the upper Illinois River Basin as part of the pilot phase of the National Water-Quality Assessment program. Data were collected monthly from April 1987-August l990; these data were supplemented with data collected during special events, including high and low flows. Each fixed station represents a cross section at which the transport of selected dissolved and suspended materials can be computed. Samples collected monthly and during special events were analyzed for concentrations of major ions, nutrients, trace elements, organic carbon, chlorophyll-a, suspended sediment, and other constituents. Field measurements of water temperature, pH, dissolved oxygen, specific conductance, and indicator bacteria also were made at each site. Samples of suspended sediment were analyzed for concentrations of major ions and trace elements. In addition, samples were analyzed seasonally for concentrations of antimony, bromide, molybdenum, and the radionuclides gross alpha and gross beta.

  7. Stations Outdoors

    ERIC Educational Resources Information Center

    Madison, John P.; And Others

    1976-01-01

    Described is a program of outdoor education utilizing activity-oriented learning stations. Described are 13 activities including: a pond study, orienteering, nature crafts, outdoor mathematics, linear distance measurement, and area measurement. (SL)

  8. Structural basis for DNA bending

    SciTech Connect

    Nadeau, J.G.; Crothers, D.M. )

    1989-04-01

    The authors report proton NMR studies on DNA oligonucleotides that contain A tracts of lengths known to produce various degrees of bending. Spectra of duplexes in the series 5{prime}-(GGCA{sub n}CGG){center dot}(CCGT{sub n}GCC) (n = 3,4,5,7,9) reveal substantial structural changes within the A{sub n}{center dot}T{sub n} tract as its length is increased. Chemical-shift comparisons show that A tracts with fewer than about seven members do not contain regions of uniform structure. Throughout the series, there is a striking monotonic relationship between the location of an A{center dot}T pair in the A tract and the relative position of its ThyH3 resonance. The direction of this chemical-shift dispersion is opposite to that expected from consideration of ring-current effects alone. This model features a substantial negative base-pair tilt, which has been suggested previously as the source of A-tract bending. In contrast, the nuclear Overhauser effect distances are inconsistent with at least one known crystallographic A-tract structure which lacks appreciable base-pair tilt.

  9. Space Station

    NASA Image and Video Library

    1970-01-01

    This is an illustration of the Space Base concept. In-house work of the Marshall Space Flight Center, as well as a Phase B contract with the McDornel Douglas Astronautics Company, resulted in a preliminary design for a space station in 1969 and l970. The Marshall-McDonnel Douglas approach envisioned the use of two common modules as the core configuration of a 12-man space station. Each common module was 33 feet in diameter and 40 feet in length and provided the building blocks, not only for the space station, but also for a 50-man space base. Coupled together, the two modules would form a four-deck facility: two decks for laboratories and two decks for operations and living quarters. Zero-gravity would be the normal mode of operation, although the station would have an artificial-gravity capability. This general-purpose orbital facility was to provide wide-ranging research capabilities. The design of the facility was driven by the need to accommodate a broad spectrum of activities in support of astronomy, astrophysics, aerospace medicine, biology, materials processing, space physics, and space manufacturing. To serve the needs of Earth observations, the station was to be placed in a 242-nautical-mile orbit at a 55-degree inclination. An Intermediate-21 vehicle (comprised of Saturn S-IC and S-II stages) would have launched the station in 1977.

  10. 4. ENVIRONMENT, FROM NORTH, SHOWING RIVER ROAD BRIDGE CARRYING CASSELMAN ...

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

    4. ENVIRONMENT, FROM NORTH, SHOWING RIVER ROAD BRIDGE CARRYING CASSELMAN RIVER ROAD OVER CASSELMAN RIVER, WITH MARYLAND GEOLOGICAL SURVEY STREAM-GAUGING STATION AT NORTHEAST CORNER OF BRIDGE - River Road Bridge, Crossing Casselman River on Casselman River Road, Grantsville, Garrett County, MD

  11. National Dam Inspection Program. Williamsburg Station Dam (NDI ID Number PA-540, DER ID Number 7-48), Susquehanna River Basin, Frankstown Branch, Juniata River, Blair County, Pennsylvania. Phase I Inspection Report

    DTIC Science & Technology

    1981-06-01

    area should be inspected during periods of low flow in the river to document the actual condition of the section. The inspection of the structure...inspected during a period of low fllow in the riverd. 6 SECTION 4 OPERATIO0AL PROCEDURES 4.1 Procedures. Water is drawn from the reservoir on an as...approximate analysis of the static stability of the gravity spillway section was performed for this study. During periods of extreme hydrometeorological

  12. Sensitivity analysis of channel-bend hydraulics influenced by vegetation

    NASA Astrophysics Data System (ADS)

    Bywater-Reyes, S.; Manners, R.; McDonald, R.; Wilcox, A. C.

    2015-12-01

    Alternating bars influence hydraulics by changing the force balance of channels as part of a morphodynamic feedback loop that dictates channel geometry. Pioneer woody riparian trees recruit on river bars and may steer flow, alter cross-stream and downstream force balances, and ultimately change channel morphology. Quantifying the influence of vegetation on stream hydraulics is difficult, and researchers increasingly rely on two-dimensional hydraulic models. In many cases, channel characteristics (channel drag and lateral eddy viscosity) and vegetation characteristics (density, frontal area, and drag coefficient) are uncertain. This study uses a beta version of FaSTMECH that models vegetation explicitly as a drag force to test the sensitivity of channel-bend hydraulics to riparian vegetation. We use a simplified, scale model of a meandering river with bars and conduct a global sensitivity analysis that ranks the influence of specified channel characteristics (channel drag and lateral eddy viscosity) against vegetation characteristics (density, frontal area, and drag coefficient) on cross-stream hydraulics. The primary influence on cross-stream velocity and shear stress is channel drag (i.e., bed roughness), followed by the near-equal influence of all vegetation parameters and lateral eddy viscosity. To test the implication of the sensitivity indices on bend hydraulics, we hold calibrated channel characteristics constant for a wandering gravel-bed river with bars (Bitterroot River, MT), and vary vegetation parameters on a bar. For a dense vegetation scenario, we find flow to be steered away from the bar, and velocity and shear stress to be reduced within the thalweg. This provides insight into how the morphodynamic evolution of vegetated bars differs from unvegetated bars.

  13. Application of Surface Geophysical Methods, With Emphasis on Magnetic Resonance Soundings, to Characterize the Hydrostratigraphy of the Brazos River Alluvium Aquifer, College Station, Texas, July 2006 - A Pilot Study

    USGS Publications Warehouse

    Shah, Sachin D.; Kress, Wade H.; Legchenko, Anatoly

    2007-01-01

    The U.S. Geological Survey, in cooperation with the Texas Water Development Board, used surface geophysical methods at the Texas A&M University Brazos River Hydrologic Field Research Site near College Station, Texas, in a pilot study, to characterize the hydrostratigraphic properties of the Brazos River alluvium aquifer and determine the effectiveness of the methods to aid in generating an improved ground-water availability model. Three non-invasive surface geophysical methods were used to characterize the electrical stratigraphy and hydraulic properties and to interpret the hydrostratigraphy of the Brazos River alluvium aquifer. Two methods, time-domain electromagnetic (TDEM) soundings and two-dimensional direct-current (2D-DC) resistivity imaging, were used to define the lateral and vertical extent of the Ships clay, the alluvium of the Brazos River alluvium aquifer, and the underlying Yegua Formation. Magnetic resonance sounding (MRS), a recently developed geophysical method, was used to derive estimates of the hydrologic properties including percentage water content and hydraulic conductivity. Results from the geophysics study demonstrated the usefulness of combined TDEM, 2D-DC resistivity, and MRS methods to reduce the need for additional boreholes in areas with data gaps and to provide more accurate information for ground-water availability models. Stratigraphically, the principal finding of this study is the relation between electrical resistivity and the depth and thickness of the subsurface hydrostratigraphic units at the site. TDEM data defined a three-layer electrical stratigraphy corresponding to a conductor-resistor-conductor that represents the hydrostratigraphic units - the Ships clay, the alluvium of the Brazos River alluvium aquifer, and the Yegua Formation. Sharp electrical boundaries occur at about 4 to 6 and 20 to 22 meters below land surface based on the TDEM data and define the geometry of the more resistive Brazos River alluvium aquifer

  14. Guanine tracts enhance sequence directed DNA bends.

    PubMed Central

    Milton, D L; Casper, M L; Wills, N M; Gesteland, R F

    1990-01-01

    Synthetic DNA fragments were constructed to determine the effect of G tracts, in conjunction with periodically spaced A tracts, on DNA bends. Relative length measurements showed that the G tracts spaced at the half helical turn enhanced the DNA bend. When the G tract was interrupted with a thymine or shortened to one or two guanines, the relative lengths decreased. If the G tract was replaced with either an A tract or a T tract, the bend was cancelled. Replacement with a C tract decreased the relative length to that of a thymine interruption suggesting that bend enhancement due to G tracts requires A tracts on the same strand. PMID:2315040

  15. Ovalization of Tubes Under Bending and Compression

    NASA Technical Reports Server (NTRS)

    Demer, L J; Kavanaugh, E S

    1944-01-01

    An empirical equation has been developed that gives the approximate amount of ovalization for tubes under bending loads. Tests were made on tubes in the d/t range from 6 to 14, the latter d/t ratio being in the normal landing gear range. Within the range of the series of tests conducted, the increase in ovalization due to a compression load in combination with a bending load was very small. The bending load, being the principal factor in producing the ovalization, is a rather complex function of the bending moment, d/t ratio, cantilever length, and distance between opposite bearing faces. (author)

  16. Protein-induced bending and DNA cyclization.

    PubMed

    Kahn, J D; Crothers, D M

    1992-07-15

    We have applied T4 ligase-mediated DNA cyclization kinetics to protein-induced bending in DNA. The presence and direction of a static bend can be inferred from J factors for cyclization of 150- to 160-base-pair minicircles, which include a catabolite activator protein binding site phased against a sequence-directed bend. We demonstrate a quasi-thermodynamic linkage between cyclization and protein binding; we find that properly phased DNAs bind catabolite activator protein approximately 200-fold more tightly as circles than as linear molecules. The results unambiguously distinguish DNA bends from isotropically flexible sites and can explain cooperative binding by proteins that need not contact each other.

  17. 8. VIEW LOOKING UPSTREAM FROM THE RIVER ARM OF THE ...

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

    8. VIEW LOOKING UPSTREAM FROM THE RIVER ARM OF THE COFFERDAM NEAR STATION (September 1936) - Mississippi River 9-Foot Channel Project, Lock & Dam No. 13, Upper Mississippi River, Fulton, Whiteside County, IL

  18. Bending Gold Nanorods with Light.

    PubMed

    Babynina, Anastasia; Fedoruk, Michael; Kühler, Paul; Meledin, Alexander; Döblinger, Markus; Lohmüller, Theobald

    2016-10-12

    V-shaped gold nanoantennas are the functional components of plasmonic metasurfaces, which are capable of manipulating light in unprecedented ways. Designing a metasurface requires the custom arrangement of individual antennas with controlled shape and orientation. Here, we show how highly crystalline gold nanorods in solution can be bent, one-by-one, into a V-shaped geometry and printed to the surface of a solid support through a combination of plasmonic heating and optical force. Significantly, we demonstrate that both the bending angle and the orientation of each rod-antenna can be adjusted independent from each other by tuning the laser intensity and polarization. This approach is applicable for the patterning of V-shaped plasmonic antennas on almost any substrate, which holds great potential for the fabrication of ultrathin optical components and devices.

  19. Peeling, sliding, pulling and bending

    NASA Astrophysics Data System (ADS)

    Lister, John; Peng, Gunnar

    2015-11-01

    The peeling of an elastic sheet away from thin layer of viscous fluid is a simply-stated and generic problem, that involves complex interactions between the flow and elastic deformation on a range of length scales. Consider an analogue of capillary spreading, where a blister of injected viscous fluid spreads due to tension in the overlying elastic sheet. Here the tension is coupled to the deformation of the sheet, and thus varies in time and space. A key question is whether or not viscous shear stresses ahead of the blister are sufficient to prevent the sheet sliding inwards and relieving the tension. Our asymptotic analysis reveals a dichotomy between fast and slow spreading, and between two-dimensional and axisymmetric spreading. In combination with bending stresses and gravity, which may dominate parts of the flow but not others, there is a plethora of dynamical regimes.

  20. Peeling, sliding, pulling and bending

    NASA Astrophysics Data System (ADS)

    Lister, John; Peng, Gunnar

    2016-11-01

    The peeling of an elastic sheet away from thin layer of viscous fluid is a simply-stated and generic problem, that involves complex interactions between the flow and elastic deformation on a range of length scales. Consider an analogue of capillary spreading, where a blister of injected viscous fluid spreads due to tension in the overlying elastic sheet. Here the tension is coupled to the deformation of the sheet, and thus varies in time and space. A key question is whether or not viscous shear stresses ahead of the blister are sufficient to prevent the sheet sliding inwards and relieving the tension. Our asymptotic analysis reveals a dichotomy between fast and slow spreading, and between two-dimensional and axisymmetric spreading. In combination with bending stresses and gravity, which may dominate parts of the flow but not others, there is a plethora of dynamical regimes.

  1. 113. TELEPHOTO VIEW OF CHESTER STATION COMPLEX FROM THE SOUTH ...

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

    113. TELEPHOTO VIEW OF CHESTER STATION COMPLEX FROM THE SOUTH SIDE OF THE COMMODORE BARRY BRIDGE THAT SPANS THE DELAWARE RIVER (DUPLICATE OF HAER No. PA-505-2) - Delaware County Electric Company, Chester Station, Delaware River at South end of Ward Street, Chester, Delaware County, PA

  2. 1. VIEW NORTH OF HAMPDEN STATION AND (AT LEFT) CHICOPEE ...

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

    1. VIEW NORTH OF HAMPDEN STATION AND (AT LEFT) CHICOPEE RIVER MOUTH; CONDENSER WATER INTAKE IS AT CENTER, END OF VIADUCT IS VISIBLE THROUGH TREES AT RIGHT - Turners Falls Power & Electric Company, Hampden Station, East bank of Connecticut River, Chicopee, Hampden County, MA

  3. Space Station

    NASA Image and Video Library

    1971-01-01

    This is an artist's concept of the Research and Applications Modules (RAM). Evolutionary growth was an important consideration in space station plarning, and another project was undertaken in 1971 to facilitate such growth. The RAM study, conducted through a Marshall Space Flight Center contract with General Dynamics Convair Aerospace, resulted in the conceptualization of a series of RAM payload carrier-sortie laboratories, pallets, free-flyers, and payload and support modules. The study considered two basic manned systems. The first would use RAM hardware for sortie mission, where laboratories were carried into space and remained attached to the Shuttle for operational periods up to 7 days. The second envisioned a modular space station capability that could be evolved by mating RAM modules to the space station core configuration. The RAM hardware was to be built by Europeans, thus fostering international participation in the space program.

  4. Space Station

    NASA Image and Video Library

    1986-08-01

    In response to President Reagan's directive to NASA to develop a permanent marned Space Station within a decade, part of the State of the Union message to Congress on January 25, 1984, NASA and the Administration adopted a phased approach to Station development. This approach provided an initial capability at reduced costs, to be followed by an enhanced Space Station capability in the future. This illustration depicts a configuration with enhanced capabilities. It builds on the horizontal boom and module pattern of the revised baseline. This configuration would feature dual keels, two vertical spines 105-meters long joined by upper and lower booms. The structure carrying the modules would become a transverse boom of a basically rectangular structure. The two new booms, 45-meters in length, would provide extensive accommodations for attached payloads, and would offer a wide field of view. Power would be increased significantly, with the addition if a 50-kW solar dynamic power system.

  5. Restorying the Self: Bending toward Textual Justice

    ERIC Educational Resources Information Center

    Thomas, Ebony Elizabeth; Stornaiuolo, Amy

    2016-01-01

    In this essay, Ebony Elizabeth Thomas and Amy Stornaiuolo explore new trends in reader response for a digital age, particularly the phenomenon of bending texts using social media. They argue that bending is one form of "restorying," a process by which people reshape narratives to represent a diversity of perspectives and experiences that…

  6. Tube-bending scale/protractor

    NASA Technical Reports Server (NTRS)

    Millett, A. U.

    1977-01-01

    Combination protractor and scale for measuring tube bends has novel pivot that allows tube to remain in contact with scale arms for all bend angles. Device permits rapid and accurate scribing and measurement of mockup fluid lines to obtain production data.

  7. Restorying the Self: Bending toward Textual Justice

    ERIC Educational Resources Information Center

    Thomas, Ebony Elizabeth; Stornaiuolo, Amy

    2016-01-01

    In this essay, Ebony Elizabeth Thomas and Amy Stornaiuolo explore new trends in reader response for a digital age, particularly the phenomenon of bending texts using social media. They argue that bending is one form of "restorying," a process by which people reshape narratives to represent a diversity of perspectives and experiences that…

  8. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  9. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  10. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  11. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  12. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  13. Observation Station

    ERIC Educational Resources Information Center

    Rutherford, Heather

    2011-01-01

    This article describes how a teacher integrates science observations into the writing center. At the observation station, students explore new items with a science theme and use their notes and questions for class writings every day. Students are exposed to a variety of different topics and motivated to write in different styles all while…

  14. Space Station

    NASA Image and Video Library

    1989-08-01

    In response to President Reagan's directive to NASA to develop a permanent marned Space Station within a decade, part of the State of the Union message to Congress on January 25, 1984, NASA and the Administration adopted a phased approach to Station development. This approach provided an initial capability at reduced costs, to be followed by an enhanced Space Station capability in the future. This illustration depicts the baseline configuration, which features a 110-meter-long horizontal boom with four pressurized modules attached in the middle. Located at each end are four photovoltaic arrays generating a total of 75-kW of power. Two attachment points for external payloads are provided along this boom. The four pressurized modules include the following: A laboratory and habitation module provided by the United States; two additional laboratories, one each provided by the European Space Agency (ESA) and Japan; and an ESA-provided Man-Tended Free Flyer, a pressurized module capable of operations both attached to and separate from the Space Station core. Canada was expected to provide the first increment of a Mobile Serving System.

  15. Space Station

    NASA Image and Video Library

    1985-12-01

    Skylab's success proved that scientific experimentation in a low gravity environment was essential to scientific progress. A more permanent structure was needed to provide this space laboratory. President Ronald Reagan, on January 25, 1984, during his State of the Union address, claimed that the United States should exploit the new frontier of space, and directed NASA to build a permanent marned space station within a decade. The idea was that the space station would not only be used as a laboratory for the advancement of science and medicine, but would also provide a staging area for building a lunar base and manned expeditions to Mars and elsewhere in the solar system. President Reagan invited the international community to join with the United States in this endeavour. NASA and several countries moved forward with this concept. By December 1985, the first phase of the space station was well underway with the design concept for the crew compartments and laboratories. Pictured are two NASA astronauts, at Marshall Space Flight Center's (MSFC) Neutral Buoyancy Simulator (NBS), practicing construction techniques they later used to construct the space station after it was deployed.

  16. Bending of light in conformal Weyl gravity

    SciTech Connect

    Sultana, Joseph; Kazanas, Demosthenes

    2010-06-15

    We reexamine the bending of light issue associated with the metric of the static, spherically symmetric solution of Weyl gravity discovered by Mannheim and Kazanas (1989). To this end we employ the procedure used recently by Rindler and Ishak to obtain the bending angle of light by a centrally concentrated spherically symmetric matter distribution in a Schwarzschild-de Sitter background. In earlier studies the term {gamma}r in the metric led to the paradoxical result of a bending angle proportional to the photon impact parameter, when using the usual formalism appropriate to asymptotically flat space-times. However, employing the approach of light bending of Rindler and Ishak we show that the effects of this term are in fact insignificant, with the discrepancy between the two procedures attributed to the definition of the bending angle between the asymptotically flat and nonflat spaces.

  17. Wire and Cable Cold Bending Test

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony

    2010-01-01

    One of the factors in assessing the applicability of wire or cable on the lunar surface is its flexibility under extreme cold conditions. Existing wire specifications did not address their mechanical behavior under cold, cryogenic temperature conditions. Therefore tests were performed to provide this information. To assess this characteristic 35 different insulated wire and cable pieces were cold soaked in liquid nitrogen. The segments were then subjected to bending and the force was recorded. Any failure of the insulation or jacketing was also documented for each sample tested. The bending force tests were performed at room temperature to provide a comparison to the change in force needed to bend the samples due to the low temperature conditions. The results from the bending tests were plotted and showed how various types of insulated wire and cable responded to bending under cold conditions. These results were then used to estimate the torque needed to unroll the wire under these low temperature conditions.

  18. Pipe and bend erosion by pneumatic transport of solids at high temperature

    NASA Astrophysics Data System (ADS)

    Klinzing, George E.; Borzone, Luis A.; Yang, Wen-Ching

    1989-06-01

    The erosion of various components of a pneumatic transport line was studied through basic experiments, commercial scale test runs and computer simulation. The main objective was to study the effect of the operating variables on the erosion rates of refractory lined straight sections and bends. Temperatures ranging from 22 to 830 C, gas velocities from 12.9 to 34 m/s and solid flow rates from 48 to 225 kg/h were tested in a High Temperature Pneumatic Transport Test Facility. Four kinds of refractory concretes were used as targets. The erodent materials were river sand, coal slag and alumina. The effect of gas velocity and solids slow rate on the erosion rate was correlated in terms of power laws, while temperature effects proved to be more complex, since mechanical properties of both erodent and target materials change with temperature. The erosion of circular bends was evaluated using a computer model that combines computational particle dynamics and experimental data to predict the erosion pattern inside the bend. Experiments on the erosion of wedge samples, performed in the erosion test facility, and data on particle-wall collisions, obtained with the help of high speed photographic techniques, were the basic set of data used in the simulation. As an alternative to circular radius bends, and experimental study of wear and flow patterns in blinded T-bends was performed. The internal geometry in this kind of bends was determined by the solids deposition, and complex erosion patterns appeared as the operating variables were manipulated.

  19. [Effects of the installation of the Rosal hydroelectric power station, Itabapoana River, States of Espírito Santo and Rio de Janeiro, on anophelinae, planorbidae and phlebotominae].

    PubMed

    Rezende, Helder Ricas; Sessa, Paulo Augusto; Ferreira, Adelson Luiz; dos Santos, Claudiney Biral; Leite, Gustavo Rocha; Falqueto, Aloísio

    2009-01-01

    The construction of dams usually changes the composition of the fauna within their areas of influence. In the area where the Rosal hydroelectric power station has been installed, in the States of Espírito Santo and Rio de Janeiro, changes to the abundance of anophelinae, planorbidae and phlebotominae were evaluated before (1998-2000) and after (2000-2005) the damming. Nine sample collection points were defined, each represented by a home and its outbuildings, shelters for domestic animals and water collection points within a radius of 150m. One hundred and three adult anophelinae were collected before the damming and 313 afterwards; 200 immature anophelinae before and 708 afterwards; 868 planorbidae before and 486 afterwards; and 2,979 phlebotominae before and 912 afterwards. The vector record, consisting of anophelinae, planorbidae and phlebotominae, shows the potential of this area for transmission of malaria, schistosomiasis and American cutaneous leishmaniasis. However, the environmental changes did not increase the risk of the occurrence of these diseases.

  20. 49 CFR 192.315 - Wrinkle bends in steel pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Wrinkle bends in steel pipe. 192.315 Section 192... Transmission Lines and Mains § 192.315 Wrinkle bends in steel pipe. (a) A wrinkle bend may not be made on steel... wrinkle bend on steel pipe must comply with the following: (1) The bend must not have any sharp kinks....

  1. 49 CFR 192.315 - Wrinkle bends in steel pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Wrinkle bends in steel pipe. 192.315 Section 192... Transmission Lines and Mains § 192.315 Wrinkle bends in steel pipe. (a) A wrinkle bend may not be made on steel... wrinkle bend on steel pipe must comply with the following: (1) The bend must not have any sharp kinks....

  2. 49 CFR 192.315 - Wrinkle bends in steel pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Wrinkle bends in steel pipe. 192.315 Section 192... Transmission Lines and Mains § 192.315 Wrinkle bends in steel pipe. (a) A wrinkle bend may not be made on steel... wrinkle bend on steel pipe must comply with the following: (1) The bend must not have any sharp kinks....

  3. 49 CFR 192.315 - Wrinkle bends in steel pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Wrinkle bends in steel pipe. 192.315 Section 192... Transmission Lines and Mains § 192.315 Wrinkle bends in steel pipe. (a) A wrinkle bend may not be made on steel... wrinkle bend on steel pipe must comply with the following: (1) The bend must not have any sharp kinks....

  4. 49 CFR 192.315 - Wrinkle bends in steel pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Wrinkle bends in steel pipe. 192.315 Section 192... Transmission Lines and Mains § 192.315 Wrinkle bends in steel pipe. (a) A wrinkle bend may not be made on steel... wrinkle bend on steel pipe must comply with the following: (1) The bend must not have any sharp kinks....

  5. Bend Properties of Sapphire Fibers at Elevated Temperatures. 1; Bend Survivability

    NASA Technical Reports Server (NTRS)

    Morscher, Gregory N.; Sayir, Haluk

    1995-01-01

    The effect of temperature on the bend radius that a c-axis-oriented sapphire fiber can withstand was determined for fibers of various diameter. Bend stress rupture tests were performed for times of 1-100 h and temperatures of 300-1700 C. Fibers would survive the bend test undeformed, would fracture or would deform. The bend survival radius was determined to be the radius above which no fibers fractured or deformed for a given time-temperature treatment. It was found that the ability of fibers to withstand curvature decreases substantially with time and increasing temperature and that fibers of smaller diameter (46-83 micron) withstood smaller bend radii than would be expected from just a difference in fiber diameter when compared with the bend results of the fibers of large diameter (144 micron). This was probably due to different flaw populations, causing high temperature bend failure for the tested sapphire fibers of different diameters.

  6. Willamette River at Lambert Bend, Oregon, bridge-site report

    USGS Publications Warehouse

    Harris, D.D.

    1969-01-01

    The Highway Department also wants to know what flow could be expected from a flood event equal to that of December 1964, but regulated by three additional reservoirs that have been completed since 1964. This design discharge will be referred to as Condition 2 in this report. Also required in Condition 2 is the amount of backwater caused by the two constrictions and how often the design flood occurred before regulation began in 1941.

  7. Analysis and detection of functional outliers in water quality parameters from different automated monitoring stations in the Nalón river basin (Northern Spain).

    PubMed

    Piñeiro Di Blasi, J I; Martínez Torres, J; García Nieto, P J; Alonso Fernández, J R; Díaz Muñiz, C; Taboada, J

    2015-01-01

    The purposes and intent of the authorities in establishing water quality standards are to provide enhancement of water quality and prevention of pollution to protect the public health or welfare in accordance with the public interest for drinking water supplies, conservation of fish, wildlife and other beneficial aquatic life, and agricultural, industrial, recreational, and other reasonable and necessary uses as well as to maintain and improve the biological integrity of the waters. In this way, water quality controls involve a large number of variables and observations, often subject to some outliers. An outlier is an observation that is numerically distant from the rest of the data or that appears to deviate markedly from other members of the sample in which it occurs. An interesting analysis is to find those observations that produce measurements that are different from the pattern established in the sample. Therefore, identification of atypical observations is an important concern in water quality monitoring and a difficult task because of the multivariate nature of water quality data. Our study provides a new method for detecting outliers in water quality monitoring parameters, using turbidity, conductivity and ammonium ion as indicator variables. Until now, methods were based on considering the different parameters as a vector whose components were their concentration values. This innovative approach lies in considering water quality monitoring over time as continuous curves instead of discrete points, that is to say, the dataset of the problem are considered as a time-dependent function and not as a set of discrete values in different time instants. This new methodology, which is based on the concept of functional depth, was applied to the detection of outliers in water quality monitoring samples in the Nalón river basin with success. Results of this study were discussed here in terms of origin, causes, etc. Finally, the conclusions as well as advantages of

  8. Averaged indicators of secondary flow in repeated acoustic Doppler current profiler crossings of bends

    USGS Publications Warehouse

    Dinehart, R.L.; Burau, J.R.

    2005-01-01

    [1] Cross-stream velocity was measured in a large river bend at high spatial resolution over three separate survey episodes. A suite of methods for resolving cross-stream velocity distributions was tested on data collected using acoustic Doppler current profilers (ADCP) in the sand-bedded Sacramento River, California. The bend was surveyed with repeated ADCP crossings at eight cross sections during a rising limb of high discharge in February 2004 and twice on recession in March 2004. By translating and interpolating repeated ADCP crossings to planar grids, velocity ensembles at similar positions along irregular boat paths could be averaged. The averaging minimized turbulent fluctuations in streamwise velocities over 1 m/s, enabling the resolution of weaker cross-stream velocities (???15-30 cm/s). Secondary-flow influence on suspended sediment was inferred from a lateral region of acoustic backscatter intensity aligned with outward flow over the point bar. A near-bed decrease in backscatter intensity across the pool corresponded with inward cross-stream flow. These suspension indicators were used to orient averaged velocity grids for unambiguously defining the cross-stream velocity magnitudes. Additional field investigations could test whether the correlation between cross-stream velocity and backscatter intensity patterns results from helical recirculation of suspended sediment to the inside of the bend. These river measurements, consistent with classic and recent laboratory studies, show that ADCP surveys can provide refined views of secondary flow and sediment movement in large rivers.

  9. Contactless laser bending of silicon microstructures

    NASA Astrophysics Data System (ADS)

    Exner, Horst; Loschner, Udo

    2003-04-01

    We are going to present a new technology for laser bending of silicon microstructures based upon a suggestion of and carried out in cooperation with Prof. Dr. J. Fr'hauf from the Technical University Chemnitz (see acknowledgement). We investigated the influence of various laser process parameters on the bending angle and its reproducibility. Bending of the silicon element as a result of the laser induced thermal stresses in the material occurs toward the incident laser beam. The bending angle depends on a lot of laser process and material parameters. In particular we found that the irra-diation regime is well suited to control the bending angle. First substantial FEM based calculations of laser induced temperature fields using a moving laser heat source show the temperature field propagation in the material and reveal some regions of complicated overheating. As a result of our experiments we show a variety of examples including mul-tiple and also continuous bendings. There are several essential advantages compared to conventional bending technologies with this new method: Laser bending is contactless without using additional tools or external forces. Because of the local laser treatment the heat flux to the neighbouring material is minimized. The laser beam can be applied through windows of glass that means to al-most hermetically sealed micro devices. So laser technology is suitable for machining of already finished microsystems. It opens up a wide field of applications in micro system technologies: clip-chip-mechanism or sliding chips for micro optical benches, the adjustment of optical mirrors or other components or the ability of continuous bending for electro-static drives and so on.

  10. Aerosol size distribution and new particle formation in western Yangtze River Delta of China: two-year measurement at the SORPES station

    NASA Astrophysics Data System (ADS)

    Qi, X. M.; Ding, A. J.; Nie, W.; Petäjä, T.; Kerminen, V.-M.; Herrmann, E.; Xie, Y. N.; Zheng, L. F.; Manninen, H.; Aalto, P.; Sun, J. N.; Xu, Z. N.; Chi, X. G.; Huang, X.; Boy, M.; Virkkula, A.; Yang, X.-Q.; Fu, C. B.; Kulmala, M.

    2015-04-01

    Aerosol particles play important roles in regional air quality and global climate change. In this study, we analyzed two-year (2011-2013) of measurements of submicron particles (6-800 nm) at a suburban site in western Yangtze River delta (YRD) of East China. The number concentrations (NCs) of particles in the nucleation, Aitken and accumulation modes were 5300 ± 5500, 8000 ± 4400, 5800 ± 3200 cm-3, respectively. Number concentrations and size distributions of submicron particles were also influenced by long-range and regional transport of air masses. The highest and lowest accumulation mode particle number concentrations were observed in air masses from YRD and coastal region, respectively. Continental air masses from inland had the highest concentrations of nucleation mode particles. New particle formation (NPF) events, apparent in 44% of the effective measurement days, occurred frequently in all the seasons except winter. Radiation and pre-existing particles were found to be the main factors influencing the occurrence of NPF events. The particle formation rate was the highest in spring (3.6 ± 2.4 cm-3 s-1), whereas the particle growth rate had the highest values in summer (12.8 ± 4.4 nm h-1). The formation rate was typically high in relatively clean air masses, whereas the growth rate tended to be high in the polluted YRD air masses. The frequency of NPF events and the growth rate showed a strong year-to-year difference. In the summer of 2013, associated with a multi-week heat wave and photochemical pollution, NPF events occurred more frequently and the growth rate was much higher than in the same period of 2012. The difference in the location and strength of sub-tropical High, which influences the air mass transport pathways and solar radiation, seems to be the driving cause for year-to-year differences. This study reported the longest continuous measurement records of submicron particles in the East China and gained a comprehensive understanding of the

  11. Initial Ares I Bending Filter Design

    NASA Technical Reports Server (NTRS)

    Jang, Jiann-Woei; Bedrossian, Nazareth; Hall, Robert; Norris, H. Lee; Hall, Charles; Jackson, Mark

    2007-01-01

    The Ares-I launch vehicle represents a challenging flex-body structural environment for control system design. Software filtering of the inertial sensor output will be required to ensure control system stability and adequate performance. This paper presents a design methodology employing numerical optimization to develop the Ares-I bending filters. The filter design methodology was based on a numerical constrained optimization approach to maximize stability margins while meeting performance requirements. The resulting bending filter designs achieved stability by adding lag to the first structural frequency and hence phase stabilizing the first Ares-I flex mode. To minimize rigid body performance impacts, a priority was placed via constraints in the optimization algorithm to minimize bandwidth decrease with the addition of the bending filters. The bending filters provided here have been demonstrated to provide a stable first stage control system in both the frequency domain and the MSFC MAVERIC time domain simulation.

  12. Bending instability in electrospinning of nanofibers

    NASA Astrophysics Data System (ADS)

    Yarin, A. L.; Koombhongse, S.; Reneker, D. H.

    2001-03-01

    A localized approximation was developed to calculate the bending electric force acting on an electrified polymer jet, which is a key element of the electrospinning process for manufacturing of nanofibers. Using this force, a far reaching analogy between the electrically driven bending instability and the aerodynamically driven instability was established. Continuous, quasi-one-dimensional, partial differential equations were derived and used to predict the growth rate of small electrically driven bending perturbations of a liquid column. A discretized form of these equations, that accounts for solvent evaporation and polymer solidification, was used to calculate the jet paths during the course of nonlinear bending instability leading to formation of large loops and resulting in nanofibers. The results of the calculations are compared to the experimental data acquired in the present work. Agreement of theory and experiment is discussed.

  13. Bending artificial muscle from nylon filaments

    NASA Astrophysics Data System (ADS)

    Mirvakili, Seyed M.; Hunter, Ian W.

    2016-04-01

    Highly oriented nylon and polyethylene fibers shrink in length and expand in diameter when heated. Using this property, in this work, for the first time we are introducing a type of bending artificial muscle from nylon filaments such as fishing line. Reversible radius of curvature of 0.23 mm-1 was achieved with maximum reversible bending amplitude of 115 mm for the nylon bending actuator. Peak force of up to 2040 mN was measured with a catch-state force of up to 40% of the active force. A 3 dB roll-off frequency of around 0.7 Hz was observed in the frequency response of the bending actuator in water.

  14. Thermal static bending of deployable interlocked booms

    NASA Technical Reports Server (NTRS)

    Staugaitis, C. L.; Predmore, R. E.

    1973-01-01

    Metal ribbons processed with a heat-forming treatment are enabled to form tubelike structures when deployed from a roll. Deployable booms of this have been utilized for gravity-gradient stabilization on the RAE, ATS, and Nimbus D satellites. An experimental thermal-mechanics test apparatus was developed to measure the thermal static bending and twist of booms up to 3 meters long. The apparatus was calibrated by using the correlation between calculated and observed thermal bending of a seamless tube. Thermal static bending values of 16 interlocked deployable booms were observed to be within a factor of 2.5 of the values calculated from seamless-tube theory. Out-of-Sun-plane thermal bending was caused by complex heat transfer across the interlocked seam. Significant thermal static twisting was not observed.

  15. 77 FR 47525 - Safety Zone, Mississippi River, Mile Marker 291 to 295

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-09

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Mississippi River, Mile Marker 291 to 295... temporary safety zone for all waters of the Lower Mississippi River, extending the entire width of the river... pattern due to dredging operations in the vicinity of Tunica Bend, Lower Mississippi River Mile...

  16. Minimal Bending Energies of Bilayer Polyhedra

    NASA Astrophysics Data System (ADS)

    Haselwandter, Christoph A.; Phillips, Rob

    2010-11-01

    Motivated by recent experiments on bilayer polyhedra composed of amphiphilic molecules, we study the elastic bending energies of bilayer vesicles forming polyhedral shapes. Allowing for segregation of excess amphiphiles along the ridges of polyhedra, we find that bilayer polyhedra can indeed have lower bending energies than spherical bilayer vesicles. However, our analysis also implies that, contrary to what has been suggested on the basis of experiments, the snub dodecahedron, rather than the icosahedron, generally represents the energetically favorable shape of bilayer polyhedra.

  17. Tool bending in New Caledonian crows

    PubMed Central

    Sugasawa, Shoko; van der Wal, Jessica E. M.; Klump, Barbara C.; St Clair, James J. H.

    2016-01-01

    ‘Betty’ the New Caledonian crow astonished the world when she ‘spontaneously’ bent straight pieces of garden wire into hooked foraging tools. Recent field experiments have revealed that tool bending is part of the species' natural behavioural repertoire, providing important context for interpreting Betty's iconic wire-bending feat. More generally, this discovery provides a compelling illustration of how natural history observations can inform laboratory-based research into the cognitive capacities of non-human animals. PMID:27853622

  18. A transparent bending-insensitive pressure sensor.

    PubMed

    Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao

    2016-05-01

    Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.

  19. A transparent bending-insensitive pressure sensor

    NASA Astrophysics Data System (ADS)

    Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao

    2016-05-01

    Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.

  20. Comparison of different secondary flow correction methods for depth-average flow calculations in bends

    NASA Astrophysics Data System (ADS)

    Qin, C. C.

    2014-12-01

    Several secondary flow correction methods had been proposed in literature to account for the 3d flow characteristics of secondary circulation which was often lost in depth-averaged models. In order to evaluate their performances in singular bend, successive reverse curvature bends and natural meander rivers, three different typical secondary flow correction methods were applied to a depth-averaged hydrodynamic model, which were Lien(L), Kalkwijk and Booij(K) and modified Finnie(F) methods. There are obviously limits to the descriptive ability of the three methods in simulating sharply bend channels, especially L method which showed qualitative error. As for successive reverse curvature bends and natural meander rivers, K method gave a better performance than the others. F method increased depth-averaged velocities on the outside of curves, while L method overestimated the whole flow field. By the order of magnitude analysis, we found that L method has done the maximum correction for the secondary flow and the minimum correction for transversal velocities was F method. Those three methods were evaluated by multiple performance criteria. The results of this study can provide some references for some practical applications.

  1. Three-dimensional flow structure and patterns of bed shear stress in an evolving compound meander bend

    USGS Publications Warehouse

    Engel, Frank; Rhoads, Bruce L.

    2016-01-01

    Compound meander bends with multiple lobes of maximum curvature are common in actively evolving lowland rivers. Interaction among spatial patterns of mean flow, turbulence, bed morphology, bank failures and channel migration in compound bends is poorly understood. In this paper, acoustic Doppler current profiler (ADCP) measurements of the three-dimensional (3D) flow velocities in a compound bend are examined to evaluate the influence of channel curvature and hydrologic variability on the structure of flow within the bend. Flow structure at various flow stages is related to changes in bed morphology over the study timeframe. Increases in local curvature within the upstream lobe of the bend reduce outer bank velocities at morphologically significant flows, creating a region that protects the bank from high momentum flow and high bed shear stresses. The dimensionless radius of curvature in the upstream lobe is one-third less than that of the downstream lobe, with average bank erosion rates less than half of the erosion rates for the downstream lobe. Higher bank erosion rates within the downstream lobe correspond to the shift in a core of high velocity and bed shear stresses toward the outer bank as flow moves through the two lobes. These erosion patterns provide a mechanism for continued migration of the downstream lobe in the near future. Bed material size distributions within the bend correspond to spatial patterns of bed shear stress magnitudes, indicating that bed material sorting within the bend is governed by bed shear stress. Results suggest that patterns of flow, sediment entrainment, and planform evolution in compound meander bends are more complex than in simple meander bends. Moreover, interactions among local influences on the flow, such as woody debris, local topographic steering, and locally high curvature, tend to cause compound bends to evolve toward increasing planform complexity over time rather than stable configurations.

  2. 27. Photocopy of scale drawing (from Station 'L' office files, ...

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

    27. Photocopy of scale drawing (from Station 'L' office files, Portland, Oregon) Portland General Electric proposal to city/state, 10/15/1929 FOUNDATION AND LOCATION OF THE STATION SCREEN HOUSE AND A LOOK AT THE TYPICAL DREDGING OF THE RIVER BED WHICH TOOK PLACE ON A PERIODIC BASIS AT STATION 'L' - Portland General Electric Company, Station "L", 1841 Southeast Water Street, Portland, Multnomah County, OR

  3. Results of High Velocity Tests at Tampa Electric Company`s Big Bend 4 FGD System.

    SciTech Connect

    DeKraker, D.P.

    1997-10-15

    Test were conducted at the Big Bend Station to determine the feasibility of scrubbing gas from an additional boiler in the existing FGD system. Testing was accomplished by increasing the gas flow from the D absorber tower and measuring the performance of this module. Key performance aspects evaluated during the testing include mist eliminator performance, SO2 removal efficiency, oxidation of absorbed SO2, and limestone utilization.

  4. Space Station

    NASA Image and Video Library

    1977-01-01

    The Marshall Space Flight Center (MSFC) and the Johnson Space Center (JSC) were each awarded 16-month contracts in April 1976 for the Space Station Systems Analysis Study (SSSAS). Grumman Aerospace Corporation was MSFC's contractor and McDornell Douglas Aerospace Company was JSC's contractor. The goal of this study was to formulate plans for a permanent operational base and laboratory facility in Earth orbit in addition to developing a space construction base design for implementing the program. An expended Space Shuttle external tank was to be the central core platform of the base, and additional pressurized modules could be added to provide laboratory facilities. This artist's concept depicts a space construction base design for implementing the SSSAS.

  5. Axisymmetric Bending Oscillations of Stellar Disks

    NASA Astrophysics Data System (ADS)

    Sellwood, J. A.

    1996-12-01

    Self-gravitating stellar disks with random motion support both exponentially growing and, in some cases, purely oscillatory axisymmetric bending modes, unlike their cold disk counterparts. A razor-thin disk with even a very small degree of random motion in the plane is both unstable and possesses a discrete spectrum of neutral modes, irrespective of the sharpness of the edge. Random motion normal to the disk plane is stabilizing but at the same time allows bending waves to couple to the internal vibrations of the particles, which causes the formerly neutral modes to decay through Landau damping. Focusing first on instabilities, I here determine the degree of random motion normal to the plane needed to suppress global, axisymmetric, bending instabilities in a family of self-gravitating disks. As found previously, bending instabilities are suppressed only when the thickness exceeds that expected from a local criterion when the degree of pressure support within the disk plane is comparable to, or exceeds, the support from rotation. Nevertheless, a modest disk thickness would seem to be adequate for the bending stability of most disk galaxies, except perhaps near their centers. The discretization of the neutral spectrum in a zero-thickness disk is due to the existence of a turning point for bending waves in a warm disk, which is absent when the disk is cold. When the disk is given a finite thickness, the discrete neutral modes generally become strongly damped through wave-particle interactions. It is surprising therefore that I find some simulations of warm, stable disks can support (quasi-)neutral, large-scale, bending modes that decay very slowly, if at all.

  6. Bend-insensitive optical fibers for FTTH applications

    NASA Astrophysics Data System (ADS)

    Li, Ming-Jun

    2009-01-01

    This paper reviews recent development in bend-insensitive fibers for fiber-to-the-home (FTTH) applications. First, requirements for bend-insensitive fibers are discussed. Then different design approaches for reducing fiber bending loss are described and compared. A new bend-insensitive fiber using the nano-engineered ring design is presented in detail.

  7. 49 CFR 192.313 - Bends and elbows.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... serviceability of the pipe. (2) Each bend must have a smooth contour and be free from buckling, cracks, or any other mechanical damage. (3) On pipe containing a longitudinal weld, the longitudinal weld must be as... Lines and Mains § 192.313 Bends and elbows. (a) Each field bend in steel pipe, other than a wrinkle bend...

  8. 49 CFR 192.313 - Bends and elbows.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... serviceability of the pipe. (2) Each bend must have a smooth contour and be free from buckling, cracks, or any other mechanical damage. (3) On pipe containing a longitudinal weld, the longitudinal weld must be as... Lines and Mains § 192.313 Bends and elbows. (a) Each field bend in steel pipe, other than a wrinkle bend...

  9. 49 CFR 192.313 - Bends and elbows.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... serviceability of the pipe. (2) Each bend must have a smooth contour and be free from buckling, cracks, or any other mechanical damage. (3) On pipe containing a longitudinal weld, the longitudinal weld must be as... Lines and Mains § 192.313 Bends and elbows. (a) Each field bend in steel pipe, other than a wrinkle bend...

  10. 49 CFR 192.313 - Bends and elbows.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... serviceability of the pipe. (2) Each bend must have a smooth contour and be free from buckling, cracks, or any other mechanical damage. (3) On pipe containing a longitudinal weld, the longitudinal weld must be as... Lines and Mains § 192.313 Bends and elbows. (a) Each field bend in steel pipe, other than a wrinkle bend...

  11. 49 CFR 192.313 - Bends and elbows.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... serviceability of the pipe. (2) Each bend must have a smooth contour and be free from buckling, cracks, or any other mechanical damage. (3) On pipe containing a longitudinal weld, the longitudinal weld must be as... Lines and Mains § 192.313 Bends and elbows. (a) Each field bend in steel pipe, other than a wrinkle bend...

  12. Arbitrary angle waveguide bends based on zero-index metamaterials

    NASA Astrophysics Data System (ADS)

    Li, Y. H.; Zhang, L. H.; Chen, Y. Q.; Feng, T. H.; Jiang, H. T.; Chen, H.

    2014-08-01

    In this paper, efficient arbitrary angle bends based on impedance-matched zero-index metamaterials (ZIMs) are proposed. Numerical simulations on ZIM-based bends are carried out in waveguide systems. The results show clearly that electromagnetic waves can tunnel through the ZIM-based bends with high transmittance at any bending angles. Moreover, a realistic ZIM-based bends are designed and fabricated on microstrip transmission line. Both simulated and experimental results confirm well the low loss and arbitrary angle bending effects in a system hiring ZIM-based microstrip ring resonator as bending corners.

  13. Using High-Resolution Field Measurements to Model Dune Kinematics in a Large Elongate Meander Bend.

    NASA Astrophysics Data System (ADS)

    Konsoer, K. M.; Rhoads, B. L.; Best, J.; Frias, C. E.; Abad, J. D.; Langendoen, E. J.

    2014-12-01

    Due to recent advances in hydroacoustic technology, such as the development of multibeam echo sounders, it is now possible to obtain highly accurate and detailed bathymetric data for river channels. These data provide the basis for detailed characterizations of bed form morphology ranging from individual ripples to composite dune fields. Theoretical models suggest that bed forms reach an equilibrium morphology based on hydraulic conditions during steady flow. However, at the scale of individual meander bends, bed form morphology will vary according to the local flow structure as influenced by overall bed morphology and planform curvature. Thus, the coevolution of flow structure, bed form morphology, and sediment transport should vary throughout a meander bend. This paper examines spatial variation in bed form characteristics and rates of bed form migration, and thus bed material transport, within a large, actively migrating, elongate meander loop. During a May 2013 flood event on Maier Bend, Wabash River (IL-IN, USA), repeat multibeam echo sounding surveys were conducted ~4 hours apart, providing estimates of dune celerity and volumetric rates of sediment transport at different locations around the bend. Three-dimensional velocity measurements, obtained using an acoustic Doppler current profiler, provide hydraulic data for evaluating interactions between flow structure and bed form morphology. Results show that bed form morphology is highly variable within the bend, ranging from barchans dunes on the upstream limb, 2D ripples across the point bar, and 3D composite dunes with wavelength of ~20 meters near the bend apex. Rates of dune celerity varied from 0.3 m/hr to 0.7 m/hr and were dependent on bed form geometry and local hydraulic conditions. The high-resolution data on flow and form are used to calibrate a 2D numerical model of sediment transport through the bend. Simulations using the calibrated model are used to evaluate the fluvial processes underlying

  14. 116. CENTRAL CONTROL STATION ELEVATIONS & SECTIONS (ML870/1FS) October ...

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

    116. CENTRAL CONTROL STATION - ELEVATIONS & SECTIONS (ML-8-70/1-FS) October 1933 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  15. 43. WEST TO DETAIL OF WHEELED SHEET METAL WORK STATION ...

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

    43. WEST TO DETAIL OF WHEELED SHEET METAL WORK STATION BEARING ON LEFT CIRCA 1900 ROLLS FOR BENDING STEEL WINDMILL BLADES TO PROPER CURVATURE AND ON RIGHT CIRCA 1900 BEADING MACHINE FOR ADDING STIFFENING CREASES TO THE EDGES OF SHEET METAL PARTS SUCH AS BLADES. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

  16. Temporal Differences in the Hydrologic Regime of the Lower Platte River, Nebraska, 1895-2006

    USGS Publications Warehouse

    Ginting, Daniel; Zelt, Ronald B.; Linard, Joshua I.

    2008-01-01

    Hydroecological Integrity Assessment Process software developed by the U.S. Geological Survey. A subset of 27 nonredundant indices (of the 171 indices) was selected using principal component analysis. Indices that described monthly streamflow?mean, maximum, minimum, skewness, and coefficients of variation?also were used. Comparison of these selected indices allowed determination of temporal differences among the six 11-water-year periods for each gaging station. The lower Platte River basin was affected by moderate to severe drought conditions in the 1934?44 period. The widespread drought was preceded by mildly to moderately wet conditions in the 1895?1906 period, followed by incipient drought to incipiently wet conditions in the 1951?61 periods and mildly wet conditions in 1966?76 period, moderately wet conditions in the 1985?1995 period, and incipient drought to mildly wet conditions in the 1996?2006 period. Monthly streamflow of the Platte River from Duncan through Louisville, Nebraska, correlated significantly with the monthly Palmer Hydrological Drought Index. Temporal differences in median values of monthly-mean and monthly-maximum streamflow measured at Duncan, North Bend, and Ashland stations between the two moderately wet periods (1895?1905 and 1985?95) indicated that streamflow storage reservoirs and regulation some time after 1906 significantly reduced monthly streamflow magnitude and amplitude?the difference between the highest and lowest median values of monthly mean streamflow. Effects of storage reservoirs on the median values of monthly-minimum streamflow were less obvious. Temporal differences among the other five periods, from 1934 through 2006 when streamflow was affected by storage and regulation, indicated the predominant effects of contrasting climate conditions on median values of monthly mean, maximum, and minimum streamflow. Significant temporal differences in monthly streamflow values were evident mainly between the two periods of greatly

  17. Variation of dissolved organic carbon transported by two Chinese rivers: The Changjiang River and Yellow River.

    PubMed

    Liu, Dong; Pan, Delu; Bai, Yan; He, Xianqiang; Wang, Difeng; Zhang, Lin

    2015-11-15

    Real-time monitoring of riverine dissolved organic carbon (DOC) and the associated controlling factors is essential to coastal ocean management. This study was the first to simulate the monthly DOC concentrations at the Datong Hydrometric Station for the Changjiang River and at the Lijin Hydrometric Station for the Yellow River from 2000 to 2013 using a multilayer back-propagation neural network (MBPNN), along with basin remote-sensing products and river in situ data. The average absolute error between the modeled values and in situ values was 9.98% for the Changjiang River and 10.84% for the Yellow River. As an effect of water dilution, the variations of DOC concentrations in the two rivers were significantly negatively affected by discharge, with lower values reported during the wet season. Moreover, vegetation growth status and agricultural activities, represented by the gross primary product (GPP) and cropland area percent (CropPer) in the river basin, respectively, also significantly affected the DOC concentration in the Changjiang River, but not the Yellow River. The monthly riverine DOC flux was calculated using modeled DOC concentrations. In particular, the riverine DOC fluxes were affected by discharge, with 71.06% being reported for the Changjiang River and 90.71% for the Yellow River. Over the past decade, both DOC concentration and flux in the two rivers have not shown significant changes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Bending sound in graphene: Origin and manifestation

    NASA Astrophysics Data System (ADS)

    Adamyan, V. M.; Bondarev, V. N.; Zavalniuk, V. V.

    2016-11-01

    It is proved that the acoustic-type dispersion of bending mode in graphene is generated by the fluctuation interaction between in-plane and out-of-plane terms in the free energy arising with account of non-linear components in the graphene strain tensor. In doing so we use an original adiabatic approximation based on the alleged (confirmed a posteriori) significant difference of sound speeds for in-plane and bending modes. The explicit expression for the bending sound speed depending only on the graphene mass density, in-plane elastic constants and temperature is deduced as well as the characteristics of the microscopic corrugations of graphene. The obtained results are in good quantitative agreement with the data of real experiments and computer simulations.

  19. FLUCTUATING MOTOR FORCES BEND GROWING MICROTUBULES

    PubMed Central

    Shekhar, Nandini; Neelam, Srujana; Wu, Jun; Ladd, Anthony JC; Dickinson, Richard B.; Lele, Tanmay P.

    2013-01-01

    Despite their rigidity, microtubules in living cells bend significantly during polymerization resulting in greater curvature than can be explained by thermal forces alone. However, the source of the non-thermal forces that bend growing microtubules remains obscure. We analyzed the motion of microtubule tips in NIH-3T3 fibroblasts expressing EGFP-EB1, a fluorescent +TIP protein that specifically binds to the growing ends of microtubules. We found that dynein inhibition significantly reduced the deviation of the growing tip from its initial trajectory. Inhibiting myosin modestly reduced tip fluctuations, while simultaneous myosin and dynein inhibition caused no further decrease in fluctuations compared to dynein inhibition alone. Our results can be interpreted with a model in which dynein linkages play a key role in generating and transmitting fluctuating forces that bend growing microtubules. PMID:24039637

  20. Distributed and Localized Deformation Along the Lebanese Restraining Bend from Geomorphic Observations and Modeling

    NASA Astrophysics Data System (ADS)

    Goren, L.; Castelltort, S.; Klinger, Y.

    2014-12-01

    The Dead Sea Fault System changes its orientation across Lebanon and forms a restraining bend. The oblique deformation along the Lebanese restraining bend is characterized by a complex suite of tectonic structures, among which, the Yammouneh Fault (YF), is believed to be the main strand that relays deformation from the southern section to the northern section of the Dead Sea Fault System. However, uncertainties regarding slip rates and strain partitioning in Lebanon still prevail. Here, we use morphometric analysis together with analytical and numerical models to constrain rates and modes of distributed and localized deformation along the Lebanese restraining bend.The rivers that drain the western flank of Mount Lebanon show a consistent counterclockwise rotation with respect to an expected orogen perpendicular orientation. Moreover, a pattern of divide disequilibrium in between these rivers emerges from an application of the χ mapping technique, which aims at estimating the degree of geometrical and topological disequilibrium in river networks. These geometrical patterns are compatible with simulation results using a landscape evolution model, which imposes a distributed velocity field along a domain that represents the western flank of Mount Lebanon. We further develop an analytical model that relates the river orientation to a set of kinematic parameters that represents a combined pure and simple shear strain field, and we find the parameters that best explain the present orientation of the western Lebanon rivers. Our results indicate that distributed deformation to the west of the YF takes as much as 30% of the relative Arabia-Sinai plate velocity since the late Miocene, and that the average slip rate along the YF during the same time interval has been 3.8-4.4 mm/yr. The theoretical model can further explain the inferred rotation from Paleomagnetic measurements.

  1. Bend detector for a pipeline pig

    SciTech Connect

    Laymon, D.; Berry, J.M.

    1986-12-16

    A bend detector is described for use on a pipeline pig assembly; the pipeline pig assembly comprising a front pig element and a rear pig element pivotally connected to each other by the bend detector, the front pig element having a longitudinally disposed housing with means for driving the pipeline assembly by the flow of a fluid through a pipeline system. The rear pig element has a longitudinally disposed housing with means for axially supporting the housing in the pipeline system. The detector includes a means for determining the distance traversed by the pipeline pig assembly through the pipeline system. The bend detector comprises a universal joint having a pair of yoke members being pivotally interconnected to a central member so as to oscillate about a pair of mutually perpendicular axes lying in a plane generally perpendicular to the axis of the pipeline, each of the yoke members having a yoke and a collar. The detector also includes a means for mounting each collar to the front pig element and the rear pig element, respectively, the central member being provided with a substantially longitudinal bore for receiving a hollow sleeve, a central opening in each collar thereby forming an axially aligned passageway with the hollow sleeve. A cable is received in the passageway and has its rear end anchored to the mounting means of the rear pig element, the forward end of the cable connected to an actuator shaft for a stylus for recording a bend along the pipeline system, whereby when the pig assembly traverses a bend. The front pig element pivots with respect to the rear pig element thereby pivoting the sleeve relative to the passageway and thereby exerting a pull on the cable causing the actuator shaft to move longitudinally rearward; thereby indicating the location and degree of the bend.

  2. Robotic Arm Comprising Two Bending Segments

    NASA Technical Reports Server (NTRS)

    Mehling, Joshua S.; Difler, Myron A.; Ambrose, Robert O.; Chu, Mars W.; Valvo, Michael C.

    2010-01-01

    The figure shows several aspects of an experimental robotic manipulator that includes a housing from which protrudes a tendril- or tentacle-like arm 1 cm thick and 1 m long. The arm consists of two collinear segments, each of which can be bent independently of the other, and the two segments can be bent simultaneously in different planes. The arm can be retracted to a minimum length or extended by any desired amount up to its full length. The arm can also be made to rotate about its own longitudinal axis. Some prior experimental robotic manipulators include single-segment bendable arms. Those arms are thicker and shorter than the present one. The present robotic manipulator serves as a prototype of future manipulators that, by virtue of the slenderness and multiple- bending capability of their arms, are expected to have sufficient dexterity for operation within spaces that would otherwise be inaccessible. Such manipulators could be especially well suited as means of minimally invasive inspection during construction and maintenance activities. Each of the two collinear bending arm segments is further subdivided into a series of collinear extension- and compression-type helical springs joined by threaded links. The extension springs occupy the majority of the length of the arm and engage passively in bending. The compression springs are used for actively controlled bending. Bending is effected by means of pairs of antagonistic tendons in the form of spectra gel spun polymer lines that are attached at specific threaded links and run the entire length of the arm inside the spring helix from the attachment links to motor-driven pulleys inside the housing. Two pairs of tendons, mounted in orthogonal planes that intersect along the longitudinal axis, are used to effect bending of each segment. The tendons for actuating the distal bending segment are in planes offset by an angle of 45 from those of the proximal bending segment: This configuration makes it possible to

  3. Minimal Bending Energies of Bilayer Polyhedra

    PubMed Central

    Haselwandter, Christoph A.; Phillips, Rob

    2011-01-01

    Motivated by recent experiments on bilayer polyhedra composed of amphiphilic molecules, we study the elastic bending energies of bilayer vesicles forming polyhedral shapes. Allowing for segregation of excess amphiphiles along the ridges of polyhedra, we find that bilayer polyhedra can indeed have lower bending energies than spherical bilayer vesicles. However, our analysis also implies that, contrary to what has been suggested on the basis of experiments, the snub dodecahedron, rather than the icosahedron, generally represents the energetically favorable shape of bilayer polyhedra. PMID:21231425

  4. Band bending in conjugated polymer layers.

    PubMed

    Lange, Ilja; Blakesley, James C; Frisch, Johannes; Vollmer, Antje; Koch, Norbert; Neher, Dieter

    2011-05-27

    We use the Kelvin probe method to study the energy-level alignment of four conjugated polymers deposited on various electrodes. Band bending is observed in all polymers when the substrate work function exceeds critical values. Through modeling, we show that the band bending is explained by charge transfer from the electrodes into a small density of states that extends several hundred meV into the band gap. The energetic spread of these states is correlated with charge-carrier mobilities, suggesting that the same states also govern charge transport in the bulk of these polymers. © 2011 American Physical Society

  5. 33 CFR 117.171 - Middle River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Middle River. 117.171 Section 117... OPERATION REGULATIONS Specific Requirements California § 117.171 Middle River. (a) The draw of the San..., mile 9.8 near Middle River Station, shall open on signal if at least 12 hours notice is given to the...

  6. 33 CFR 117.171 - Middle River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Middle River. 117.171 Section 117... OPERATION REGULATIONS Specific Requirements California § 117.171 Middle River. (a) The draw of the San..., mile 9.8 near Middle River Station, shall open on signal if at least 12 hours notice is given to the...

  7. 33 CFR 117.171 - Middle River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Middle River. 117.171 Section 117... OPERATION REGULATIONS Specific Requirements California § 117.171 Middle River. (a) The draw of the San..., mile 9.8 near Middle River Station, shall open on signal if at least 12 hours notice is given to the...

  8. 33 CFR 117.171 - Middle River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Middle River. 117.171 Section 117... OPERATION REGULATIONS Specific Requirements California § 117.171 Middle River. (a) The draw of the San..., mile 9.8 near Middle River Station, shall open on signal if at least 12 hours notice is given to the...

  9. 33 CFR 117.171 - Middle River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Middle River. 117.171 Section 117... OPERATION REGULATIONS Specific Requirements California § 117.171 Middle River. (a) The draw of the San..., mile 9.8 near Middle River Station, shall open on signal if at least 12 hours notice is given to the...

  10. Depth and velocity data in the Lower San Joaquin River, California, 2011-2014

    USGS Publications Warehouse

    Marineau, Mathieu D.; Wright, Scott A.; Whealdon-Haught, Dan; Kinzel, Paul J.

    2017-01-01

    This data release contains water depth, depth-averaged water velocity, and river stationing (based on 2012 ortho-imagery) in select locations in the Lower San Joaquin River, California, 2011-2014. Between 2011 and 2014, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service (USFWS), collected approximately 105 channel cross-sections and multiple longitudinal profiles, which comprised of nearly 150,000 streamflow-velocity measurements and 246,000 water-depth measurements in various reaches and subreaches of the Lower San Joaquin River between Orestimba Creek and Sturgeon Bend. The data collection locations in the Lower San Joaquin River were selected based on discussions with USFWS to overlap with their sturgeon monitoring sites and areas that may provide beneficial spawning habitat (such as adjacent to gravel bars or known deep scour holes, etc.). An acoustic Doppler current profiler (ADCP) was primarily used to collect the depth and velocity data, however, in 2011 a multibeam sonar was used to map bathymetry in some areas.

  11. The life of a meander bend: Connecting shape and dynamics via analysis of a numerical model

    NASA Astrophysics Data System (ADS)

    Schwenk, Jon; Lanzoni, Stefano; Foufoula-Georgiou, Efi

    2015-04-01

    Analysis of bend-scale meandering river dynamics is a problem of theoretical and practical interest. This work introduces a method for extracting and analyzing the history of individual meander bends from inception until cutoff (called "atoms") by tracking backward through time the set of two cutoff nodes in numerical meander migration models. Application of this method to a simplified yet physically based model provides access to previously unavailable bend-scale meander dynamics over long times and at high temporal resolutions. We find that before cutoffs, the intrinsic model dynamics invariably simulate a prototypical cutoff atom shape we dub simple. Once perturbations from cutoffs occur, two other archetypal cutoff planform shapes emerge called long and round that are distinguished by a stretching along their long and perpendicular axes, respectively. Three measures of meander migration—growth rate, average migration rate, and centroid migration rate—are introduced to capture the dynamic lives of individual bends and reveal that similar cutoff atom geometries share similar dynamic histories. Specifically, through the lens of the three shape types, simples are seen to have the highest growth and average migration rates, followed by rounds, and finally longs. Using the maximum average migration rate as a metric describing an atom's dynamic past, we show a strong connection between it and two metrics of cutoff geometry. This result suggests both that early formative dynamics may be inferred from static cutoff planforms and that there exists a critical period early in a meander bend's life when its dynamic trajectory is most sensitive to cutoff perturbations. An example of how these results could be applied to Mississippi River oxbow lakes with unknown historic dynamics is shown. The results characterize the underlying model and provide a framework for comparisons against more complex models and observed dynamics.

  12. Spectral Analysis of Columbia River Estuary Currents.

    DTIC Science & Technology

    1985-09-01

    D-A1i6i 689 SPECTRAL ANALYSIS OF COLUMBIA RIVER ESTUARY CURRENTS 1/2 (U) ARMY E GINEER VATERWAYS EXPERIMENT STATION VICKCSBURG MS HYDRAULICS LAB B...26 PART IV: ANALYSIS PROCEDURES. .................... 29 *PART V: RESULTS AND DISCUSSION .. ................. 32 Astoria Winds...45 eStation T11B..........................46 Station T12. .......................... 46 Summary of Results

  13. Northern view of inside diameter welding station of the saw ...

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

    Northern view of inside diameter welding station of the saw line in bay9 of the main pipe mill building. - U.S. Steel National Tube Works, Main Pipe Mill Building, Along Monongahela River, McKeesport, Allegheny County, PA

  14. MAIN HYDRAULIC OIL TANK FOR GOVERNORS, AND 56 KW STATION ...

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

    MAIN HYDRAULIC OIL TANK FOR GOVERNORS, AND 56 KW STATION GENERATOR WITH MECHANICAL GOVERNOR. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Glines Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  15. ORIGINAL 1912 STATION POWER TRANSFORMERS IN HIGHTENSION ROOM, SW CORNER ...

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

    ORIGINAL 1912 STATION POWER TRANSFORMERS IN HIGH-TENSION ROOM, SW CORNER OF THE POWERHOUSE. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  16. 5. ROSS POWERHOUSE: SAME CAMERA STATION AS ABOVE PHOTO BUT ...

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

    5. ROSS POWERHOUSE: SAME CAMERA STATION AS ABOVE PHOTO BUT LOOKING EAST. NOTE INFORMATION DISPLAY FOR TOURISTS AT FLOOR LEVEL, 1987. - Skagit Power Development, Ross Powerhouse, On Skagit River, 10.7 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  17. 31. INTERIOR VIEW OF MAIN LOCK, WITH CENTRAL CONTROL STATION ...

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

    31. INTERIOR VIEW OF MAIN LOCK, WITH CENTRAL CONTROL STATION IN RIGHT BACKGROUND, LOOKING SOUTHEAST, DOWNSTREAM - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  18. 53. INTERIOR VIEW OF CENTRAL CONTROL STATION, GIVING A DETAIL ...

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

    53. INTERIOR VIEW OF CENTRAL CONTROL STATION, GIVING A DETAIL VIEW OF THE CENTRAL CONTROL PANEL, LOOKING WEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  19. 52. INTERIOR VIEW OF CENTRAL CONTROL STATION, FIRST FLOOR, SHOWING ...

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

    52. INTERIOR VIEW OF CENTRAL CONTROL STATION, FIRST FLOOR, SHOWING GENERATOR ENGINE AND CENTRAL CONTROL PANEL, LOOKING SOUTH - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  20. 54. INTERIOR VIEW OF CENTRAL CONTROL STATION, GIVING A DETAIL ...

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

    54. INTERIOR VIEW OF CENTRAL CONTROL STATION, GIVING A DETAIL VIEW OF THE CENTRAL CONTROL PANEL, LOOKING SOUTHWEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  1. 92. ELECTRICAL SYSTEM CENTRAL CONTROL STATION GENERAL ARRANGEMENT ...

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

    92. ELECTRICAL SYSTEM - CENTRAL CONTROL STATION - GENERAL ARRANGEMENT OF MACHINERY (ML-5-71/1-FS), January 1934 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  2. 31. INTERIOR VIEW OF MAIN LOCK, WITH CENTRAL CONTROL STATION ...

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

    31. INTERIOR VIEW OF MAIN LOCK, WITH CENTRAL CONTROL STATION IN RIGHT BACKGROUND, LOOKING NORTHEAST, UPSTREAM - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  3. 51. INTERIOR VIEW OF CENTRAL CONTROL STATION ON FIRST FLOOR, ...

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

    51. INTERIOR VIEW OF CENTRAL CONTROL STATION ON FIRST FLOOR, SHOWING CENTRAL CONTROL PANEL AND GENERATOR MOTOR, LOOKING SOUTHWEST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  4. 27. VIEW, LOOKING SOUTHWEST, SHOWING FLOOD GAUGE STATION AT NORTHEAST ...

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

    27. VIEW, LOOKING SOUTHWEST, SHOWING FLOOD GAUGE STATION AT NORTHEAST CORNER OF BRIDGE - East Bloomsburg Bridge, Spanning Susquehanna River at Pennsylvania Route 487 (Legislative Route 283), Bloomsburg, Columbia County, PA

  5. 19. DETAIL VIEW OF UPPER EAST WALL CONTROL STATION, SHOWING ...

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

    19. DETAIL VIEW OF UPPER EAST WALL CONTROL STATION, SHOWING EMERGENCY BULKHEAD STIFFLEG DERRICK TO RIGHT, LOOKING WEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  6. Delocalization and stretch-bend mixing of the HOH bend in liquid water

    NASA Astrophysics Data System (ADS)

    Carpenter, William B.; Fournier, Joseph A.; Biswas, Rajib; Voth, Gregory A.; Tokmakoff, Andrei

    2017-08-01

    Liquid water's rich sub-picosecond vibrational dynamics arise from the interplay of different high- and low-frequency modes evolving in a strong yet fluctuating hydrogen bond network. Recent studies of the OH stretching excitations of H2O indicate that they are delocalized over several molecules, raising questions about whether the bending vibrations are similarly delocalized. In this paper, we take advantage of an improved 50 fs time-resolution and broadband infrared (IR) spectroscopy to interrogate the 2D IR lineshape and spectral dynamics of the HOH bending vibration of liquid H2O. Indications of strong bend-stretch coupling are observed in early time 2D IR spectra through a broad excited state absorption that extends from 1500 cm-1 to beyond 1900 cm-1, which corresponds to transitions from the bend to the bend overtone and OH stretching band between 3150 and 3550 cm-1. Pump-probe measurements reveal a fast 180 fs vibrational relaxation time, which results in a hot-ground state spectrum that is the same as observed for water IR excitation at any other frequency. The fastest dynamical time scale is 80 fs for the polarization anisotropy decay, providing evidence for the delocalized or excitonic character of the bend. Normal mode analysis conducted on water clusters extracted from molecular dynamics simulations corroborate significant stretch-bend mixing and indicate delocalization of δHOH on 2-7 water molecules.

  7. Single molecule FRET shows uniformity in TBP-induced DNA bending and heterogeneity in bending kinetics†

    PubMed Central

    Blair, Rebecca H.; Goodrich, James A.; Kugel, Jennifer F.

    2012-01-01

    TATA binding protein (TBP) is a key component of the eukaryotic RNA polymerase II (Pol II) transcription machinery that binds to TATA boxes located in the core promoter regions of many genes. Structural and biochemical studies have shown that when TBP binds DNA, it sharply bends the DNA. We used single-molecule FRET (smFRET) to study DNA bending by human TBP on consensus and mutant TATA boxes in the absence and presence of TFIIA. We found that the state of the bent DNA within populations of TBP/DNA complexes is homogeneous; partially bent intermediates were not observed. In contrast to previous ensemble studies, TBP was found to bend a mutant TATA box to the same extent as the consensus TATA box. Moreover, in the presence of TFIIA the extent of DNA bending was not significantly changed, although TFIIA did increase the fraction of DNA molecules bound by TBP. Analysis of the kinetics of DNA bending and unbending revealed that on the consensus TATA box two kinetically distinct populations of TBP/DNA complexes exist, however, the bent state of the DNA is the same in the two populations. Our smFRET studies reveal that human TBP bends DNA in a largely uniform manner under a variety of different conditions, which was unexpected given previous ensemble biochemical studies. Our new observations lead to us to revise the model for the mechanism of DNA binding by TBP and for how DNA bending is affected by TATA sequence and TFIIA. PMID:22934924

  8. Spatio-temporal variation in bed-material load using dune topography collected during a severe flood on the coastal Trinity River, east TX, USA

    NASA Astrophysics Data System (ADS)

    Mason, J.; Mohrig, D. C.

    2015-12-01

    A series of six repeat surveys along 27 kilometers of the coastal Trinity River in east Texas, USA, reveal the temporal and spatial changes in bed material load during and following a historically large flood. The river event was above the National Weather Service flood stage for 55 days at the Liberty USGS station, and had a maximum discharge of about 80,000 cfs. As a community, we are beginning to understand how fluvial geomorphology is influenced by the backwater effect, but we still lack an understanding of how the bed-material transport adjusts to accommodate larger-scale changes in river bend pattern and kinematics. Survey data from this project includes sidescan sonar along the channel centerline, multibeam bathymetry, and channel bed sediment samples. In combination, this data set provides new insight into how and when bed material, primarily medium sand with some pebbles, moves through this region, and how this connects to previously observed changes in channel geometry (including downstream decreases in channel width to depth ratio, bar form volume and surface area, and lateral migration rates of river bends). Preliminary examination of sidescan sonar of two bends within the survey area, one upstream and one downstream, reveal a striking difference in bedform behavior in response to the changing hydrograph. Upstream, bedforms decrease 80% in height and 83% in length and increase in 3-dimensionality throughout the extended peak flow. During the falling limb of the flood these same bedforms increase in size as they become more laterally continuous and straight-crested. Downstream, 3-dimensional bedforms decrease 80% in height and 87% in length throughout the extended peak flow and then remain this size during the falling limb of the flood. This presentation will discuss these results with respect to backwater dynamics, sediment supply and transport, implications for coastal geomorphology as well as sediment delivery into deltaic systems.

  9. Aerospace crew station design

    NASA Technical Reports Server (NTRS)

    Carr, Gerald P. (Editor); Montemerlo, Melvin D. (Editor)

    1984-01-01

    Consideration is given to spacecraft cockpits and work stations, commercial aircraft cockpits and crew stations, high performance aircraft cockpits and crew stations, and space stations and habitat crew stations. Particular attention is given to an historical review of NASA manned spacecraft crew stations, ESA spacelab crew stations, the evolution of commercial aircraft flight station design, Boeing 757/767 flight deck, a historical review of Concorde flight deck design, trends in the cockpit design of new European fighters, and state-of-the-art applications for Space Station crew interface design.

  10. Three-Dimensional Gravity-Current Flow Within a Subaqueous Bend: Spatial Evolution and Force Balance Variations

    NASA Astrophysics Data System (ADS)

    Parsons, D. R.; Peakall, J.; Wei, T.; Best, J. L.; Chen, Z.; Zhao, B.

    2012-12-01

    The nature of three-dimensional flow in submarine channel bends is poorly understood, largely due to the absence of detailed data from natural channels. Here data from density-driven flows in a large reservoir on the Yellow River are presented showing the spatio-temporal variation of flow around a subaqueous bend. The data demonstrate for the first time that reversed helical flow, relative to that found in river channel bends, can occur from the centrifugal forcing of flow, even when the Coriolis force acts in the opposite direction. The data also suggest that reversed helical flow fields in submarine channels may be considerably more frequent than currently estimated, notably for bends where Coriolis and centrifugal forces combine. Additionally, our study provides the first field evidence suggesting that sinuous submarine channels can exhibit asymmetry in helical flow orientation between left and right-turning bends, with major implications for the morphodynamics of submarine channels and their resultant patterns of sedimentation and the distribution of depositional units across submarine fans.

  11. Probing the elastic limit of DNA bending.

    PubMed

    Le, Tung T; Kim, Harold D

    2014-01-01

    Sharp bending of double-stranded DNA (dsDNA) plays an essential role in genome structure and function. However, the elastic limit of dsDNA bending remains controversial. Here, we measured the opening rates of small dsDNA loops with contour lengths ranging between 40 and 200 bp using single-molecule Fluorescence Resonance Energy Transfer. The relationship of loop lifetime to loop size revealed a critical transition in bending stress. Above the critical loop size, the loop lifetime changed with loop size in a manner consistent with elastic bending stress, but below it, became less sensitive to loop size, indicative of softened dsDNA. The critical loop size increased from ∼ 60 bp to ∼ 100 bp with the addition of 5 mM magnesium. We show that our result is in quantitative agreement with the kinkable worm-like chain model, and furthermore, can reproduce previously reported looping probabilities of dsDNA over the range between 50 and 200 bp. Our findings shed new light on the energetics of sharply bent dsDNA.

  12. Strong bending of the DNA double helix

    PubMed Central

    Vologodskii, Alexander; D. Frank-Kamenetskii, Maxim

    2013-01-01

    During the past decade, the issue of strong bending of the double helix has attracted a lot of attention. Here, we overview the major experimental and theoretical developments in the field sorting out reliably established facts from speculations and unsubstantiated claims. Theoretical analysis shows that sharp bends or kinks have to facilitate strong bending of the double helix. It remains to be determined what is the critical curvature of DNA that prompts the appearance of the kinks. Different experimental and computational approaches to the problem are analyzed. We conclude that there is no reliable evidence that any anomalous behavior of the double helix happens when DNA fragments in the range of 100 bp are circularized without torsional stress. The anomaly starts at the fragment length of about 70 bp when sharp bends or kinks emerge in essentially every molecule. Experimental data and theoretical analysis suggest that kinks may represent openings of isolated base pairs, which had been experimentally detected in linear DNA molecules. The calculation suggests that although the probability of these openings in unstressed DNA is close to 10−5, it increases sharply in small DNA circles reaching 1 open bp per circle of 70 bp. PMID:23677618

  13. Age of the Hawaiian-Emperor bend

    USGS Publications Warehouse

    Dalrymple, G.B.; Clague, D.A.

    1976-01-01

    40Ar/39Ar age data on alkalic and tholeiitic basalts from Diakakuji and Kinmei Seamounts in the vicinity of the Hawaiian-Emperor bend indicate that these volcanoes are about 41 and 39 m.y. old, respectively. Combined with previously published age data on Yuryaku and Ko??ko Seamounts, the new data indicate that the best age for the bend is 42.0 ?? 1.4 m.y. Petrochemical data indicate that the volcanic rocks recovered from bend seamounts are indistinguishable from Hawaiian volcanic rocks, strengthening the hypothesis that the Hawaiian-Emperor bend is part of the Hawaiian volcanic chain. 40Ar/39Ar total fusion ages on altered whole-rock basalt samples are consistent with feldspar ages and with 40Ar/39Ar incremental heating data and appear to reflect the crystallization ages of the samples even though conventional K-Ar ages are significantly younger. The cause of this effect is not known but it may be due to low-temperature loss of 39Ar from nonretentive montmorillonite clays that have also lost 40Ar. ?? 1976.

  14. Design of a hydraulic bending machine

    Treesearch

    Steven G. Hankel; Marshall Begel

    2004-01-01

    To keep pace with customer demands while phasing out old and unserviceable test equipment, the staff of the Engineering Mechanics Laboratory (EML) at the USDA Forest Service, Forest Products Laboratory, designed and assembled a hydraulic bending test machine. The EML built this machine to test dimension lumber, nominal 2 in. thick and up to 12 in. deep, at spans up to...

  15. Bending rate damping in elastic systems

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Wang, Y.; Fabiano, R. H.

    1989-01-01

    Preliminary results of an investigation of the bending rate damping model for elastic structures are presented. A model for which the internal damping term is physically plausible and which can accomodate cantilevered boundary conditions is discussed. The model formulation and mathematical foundations are given, and numerical results are discussed.

  16. Monitoring the Bending Stiffness of DNA

    NASA Astrophysics Data System (ADS)

    Yuan, Chongli; Lou, Xiongwen; Rhoades, Elizabeth; Chen, Huimin; Archer, Lynden

    2007-03-01

    In eukaryotic cells, the accessibility of genomic sequences provides an inherent regulation mechanism for gene expression through variations in bending stiffness encoded by the nucleic acid sequence. Cyclization of dsDNA is the prevailing method for determining DNA bending stiffness. Recent cyclization data for short dsDNA raises several fundamental questions about the soundness of the cyclization method, particularly in cases where the probability of highly bent DNA conformations is low. We herein evaluate the role of T4 DNA ligase in the cyclization reaction by inserting an environmental sensitive base analogue, 2-amino purine, to the DNA molecule. By monitoring the 2-AP fluorescence under standard cyclization conditions, it is found that in addition to trapping highly-bent cyclic DNA conformations, T4 DNA ligase enhances the apparent base pair flip out rate, thus exaggerating the measured flexibility. This result is further confirmed using fluorescence anisotropy experiments. We show that fluorescence resonance energy transfer (FRET) measurements on suitably labeled dsDNA provides an alternative approach for quantifying the bending stiffness of short fragments. DNA bending stiffness results obtained using FRET are compared with literature values.

  17. Interdisciplinary Invitations: Exploring Gee's Bend Quilts

    ERIC Educational Resources Information Center

    Mitchell, Rebecca; Whitin, Phyllis; Whitin, David

    2012-01-01

    Engaging with the quilts of Gee's Bend offers a rich opportunity for students in grades four through eight to develop appreciation for pattern, rhythm, and innovation while learning about history, entrepreneurship, and political activism. By easily accessing print, film, and Internet resources teachers can include these vibrant quilts and…

  18. Interdisciplinary Invitations: Exploring Gee's Bend Quilts

    ERIC Educational Resources Information Center

    Mitchell, Rebecca; Whitin, Phyllis; Whitin, David

    2012-01-01

    Engaging with the quilts of Gee's Bend offers a rich opportunity for students in grades four through eight to develop appreciation for pattern, rhythm, and innovation while learning about history, entrepreneurship, and political activism. By easily accessing print, film, and Internet resources teachers can include these vibrant quilts and…

  19. Plastic properties of matrix composites in bending

    NASA Astrophysics Data System (ADS)

    Novikov, V. V.; Papkovskaya, O. B.

    1997-11-01

    Using the methods of integrated cross-sections and elastic solutions, we solve an elastico-plastic problem of bending of a Kirchhoff inhomogeneous square plate. The elastico-plastic properties and the effective yield stress of the inhomogeneous plate are calculated on an electronic computer. The computational results form the basis for a qualitative analysis and for the conclusions made.

  20. Strong bending of the DNA double helix.

    PubMed

    Vologodskii, Alexander; Frank-Kamenetskii, Maxim D

    2013-08-01

    During the past decade, the issue of strong bending of the double helix has attracted a lot of attention. Here, we overview the major experimental and theoretical developments in the field sorting out reliably established facts from speculations and unsubstantiated claims. Theoretical analysis shows that sharp bends or kinks have to facilitate strong bending of the double helix. It remains to be determined what is the critical curvature of DNA that prompts the appearance of the kinks. Different experimental and computational approaches to the problem are analyzed. We conclude that there is no reliable evidence that any anomalous behavior of the double helix happens when DNA fragments in the range of 100 bp are circularized without torsional stress. The anomaly starts at the fragment length of about 70 bp when sharp bends or kinks emerge in essentially every molecule. Experimental data and theoretical analysis suggest that kinks may represent openings of isolated base pairs, which had been experimentally detected in linear DNA molecules. The calculation suggests that although the probability of these openings in unstressed DNA is close to 10(-5), it increases sharply in small DNA circles reaching 1 open bp per circle of 70 bp.

  1. Aerosol deposition in bends with turbulent flow

    SciTech Connect

    McFarland, A.R.; Gong, H.; Wente, W.B.

    1997-08-01

    The losses of aerosol particles in bends were determined numerically for a broad range of design and operational conditions. Experimental data were used to check the validity of the numerical model, where the latter employs a commercially available computational fluid dynamics code for characterizing the fluid flow field and Lagrangian particle tracking technique for characterizing aerosol losses. Physical experiments have been conducted to examine the effect of curvature ratio and distortion of the cross section of bends. If it curvature ratio ({delta} = R/a) is greater than about 4, it has little effect on deposition, which is in contrast with the recommendation given in ANSI N13.1-1969 for a minimum curvature ratio of 10. Also, experimental results show that if the tube cross section is flattened by 25% or less, the flattening also has little effect on deposition. Results of numerical tests have been used to develop a correlation of aerosol penetration through a bend as a function of Stokes number (Stk), curvature ratio ({delta}) and the bend angle ({theta}). 17 refs., 10 figs., 2 tabs.

  2. Oceanic Plate Bending Along the Manila Trench

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Lin, J.; Zhan, W.

    2014-12-01

    We quantify along-trench variations in plate flexural bending along the Manila trench in the South China Sea. A 3-D interpreted flexural deformation surface of the subducting South China Sea Plate was obtained by removing from the observed bathymetry the effects of sediment loading, isostatically-compensated topography based on gravity modeling, age-related lithospheric thermal subsidence, and residual short-wavelength features. We analyzed flexural bending of 21 across-trench profile sections along the Manila trench and then calculated five best-fitting tectonic and plate parameters that control the flexural bending for each of the across-trench profile sections. Results of analysis revealed significant along-trench variations: The trench relief of the Manila trench varies from 0.8 to 2.2 km, trench-axis vertical loading (-V0) from -0.4x1012 to 1.21x1012 N/m, and axial bending moment (-M0) from 0.005x1017 to 0.6x1017 N. The effective elastic plate thickness seaward of the Manila outer-rise region (TeM) ranges from 30 to 40 km, while that trench-ward of the outer-rise (Tem) ranges from 11 to 30 km. This corresponds to a reduction in Te of 26-63% for the Manila trench. The transition from TeM to Tem occurs at a breaking distance of 50-120 km from the Manila trench axis. The axial vertical loading, bending moment, and the effective elastic thickness of the Manila trench are much smaller than the Mariana trench (Zhang et al., 2014). The contrast in the flexural bending between the Mariana and Manila trenches might be related to the difference in the ages of the subducting plates and other tectonic variables. Zhang, F., Lin, J., Zhan, W., 2014. Variations in oceanic plate bending along the Mariana trench, Earth Planet. Sci. Lett. 401, 206-214. doi: 10.1016/j.epsl.2014.05.032

  3. A chaos model of meandering rivers

    SciTech Connect

    Stoelum, H.H.

    1991-03-01

    A meandering river is a nonlinear dynamic system, and fractal geometry describes well the meander bends of such rivers. Based on a qualitative, sedimentological model of the process of meandering, a chaos model is proposed, describing meandering as the outcome of two processes: the feedback interaction between river curvature and a high-velocity thalweg channel within the river; and the interaction between meander bends causing abandonment and straightening of the river course. The system, when initiated from a nearly straight river course, moves toward a dynamic equilibrium in which the meander bends are fractal. This development is a case of self-organized criticality. The equilibrium represents a state of optimal energy dissipation in a situation where two counteracting processes are balancing each other. Sedimentology may be seen as the science that describes how nonlinear dynamic processes interact to create a depositional system. As indicated by the example of meandering rivers, the use of chaos and fractal models may give sedimentology a new turn toward understanding sedimentary processes and the 3-D architecture of sediment bodies.

  4. Bending effects on lasing action of semiconductor nanowires.

    PubMed

    Yang, Weisong; Ma, Yaoguang; Wang, Yipei; Meng, Chao; Wu, Xiaoqin; Ye, Yu; Dai, Lun; Tong, Limin; Liu, Xu; Yang, Qing

    2013-01-28

    High flexibility has been one of advantages for one-dimensional semiconductor nanowires (NWs) in wide application of nanoscale integrated circuits. We investigate the bending effects on lasing action of CdSe NWs. Threshold increases and differential efficiency decreases gradually when we decrease the bending radius step by step. Red shift and mode reduction in the output spectra are also observed. The bending loss of laser oscillation is considerably larger than that of photoluminescence (PL), and both show the exponential relationship with the bending radius. Diameter and mode dependent bending losses are investigated. Furthermore, the polarizations of output can be modulated linearly by bending the NWs into different angles continuously.

  5. Experimental Characterization of Stretch-Bending Formability of AHSS Sheets

    NASA Astrophysics Data System (ADS)

    Kitting, Daniela; Ofenheimer, Aldo; Pauli, Heinrich; Till, Edwin T.

    2011-05-01

    Deformation conditions of combined stretching and bending are known to enhance material formability compared to forming conditions without bending (e.g. in-plane stretching). These phenomena can be observed for most conventional steel grades but is even more pronounced for Advanced High Strength Steel (AHSS) sheets. Consequently, there is an urgent need in industry to quantify the phenomena of enhanced material formability due to bending effects. In this work new stretch-bend test setups are presented which can be used in addition to the conventional Angular Stretch Bend Test to systematically investigate the influence of various stretch-bending deformation conditions on the formability of AHSS sheets.

  6. International Space Station Overview

    NASA Technical Reports Server (NTRS)

    Bates, William V., Jr.

    1999-01-01

    The overview of the International Space Station (ISS) is comprised of the program vision and mission; Space Station uses; definition of program phases; as well as descriptions and status of several scheduled International Space Station Overview assembly flights.

  7. Intelligent Virtual Station (IVS)

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Intelligent Virtual Station (IVS) is enabling the integration of design, training, and operations capabilities into an intelligent virtual station for the International Space Station (ISS). A viewgraph of the IVS Remote Server is presented.

  8. Space Station Freedom

    NASA Technical Reports Server (NTRS)

    1991-01-01

    In 1982, the Space Station Task Force was formed, signaling the initiation of the Space Station Freedom Program, and eventually resulting in the Marshall Space Flight Center's responsibilities for Space Station Work Package 1.

  9. Intelligent Virtual Station (IVS)

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Intelligent Virtual Station (IVS) is enabling the integration of design, training, and operations capabilities into an intelligent virtual station for the International Space Station (ISS). A viewgraph of the IVS Remote Server is presented.

  10. Observations on unmeasured rivers

    USGS Publications Warehouse

    Leopold, Luna Bergere; Skibitzke, Herbert E.

    1967-01-01

    An analysis of data on hydraulic parameters collected during a single boat trip down a river system is presented, plotted in form of the hydraulic geometry. A dimensionless rating curve is used to estimate bankfull and average discharge for basins of various sizes. When compared with gaging station data, estimates of bankfull discharge are as consistent and possibly equal in accuracy to estimates made from gaging station data. Estimates of average discharge are less consistent; within the range of drainage areas represented by the gaging stations, errors of estimate vary from 0 to 58 percent. Local variations of bed material size along the river are compensated mostly by changes in local channel slope and roughness and do not much affect the progressive downstream changes in width, depth, or velocity.

  11. [KCl] Dependence of B-DNA Groove Bending Anisotropy.

    PubMed

    Ma, Ning; van der Vaart, Arjan

    2017-06-01

    The energetics of B-DNA bending toward the major and minor grooves were quantified by free energy simulations at four different KCl concentrations. Increased [KCl] led to more flexible DNA, with persistence lengths that agreed well with experimental values. At all salt concentrations, major groove bending was preferred, although preferences for major and minor groove bending were similar for the A-tract containing sequence. Since the phosphate repulsions and DNA internal energy favored minor groove bending, the preference for major groove bending was thought to originate from differences in solvation. Water in the minor groove was tighter bound than water in the major groove, and harder to displace than major groove water, which favored the compression of the major groove upon bending. Higher [KCl] decreased the persistence length for both major and minor groove bending but did not greatly affect the free energy spacing between the minor and major groove bending curves. For sequences without A-tracts, salt affected major and minor bending to nearly the same degree, and did not change the preference for major groove bending. For the A-tract containing sequence, an increase in salt concentration decreased the already small energetic difference between major and minor groove bending. Since salts did not significantly affect the relative differences in bending energetics and hydration, it is likely that the increased bending flexibilities upon salt increase are simply due to screening.

  12. Meandering down to the Sea: The Wandering Ways of Rivers.

    ERIC Educational Resources Information Center

    Aslamazov, Lev

    1992-01-01

    Discusses the hydrodynamic reasons why a riverbed meanders through a plain. Describes how water movement at a bend in a river causes erosion and changes in the riverbed. Provides a mathematical model to explain the periodic shape of meanders of a river in a plain. (MDH)

  13. Index of stations: surface-water data-collection network of Texas, September 1998

    USGS Publications Warehouse

    Gandara, Susan C.; Barbie, Dana L.

    1999-01-01

    As of September 30, 1998, the surface-water data-collection network of Texas (table 1) included 313 continuous-recording streamflow stations (D), 22 gage-height record only stations (G), 23 crest-stage partial-record stations (C), 39 flood-hydrograph partial-record stations (H), 25 low-flow partial-record stations (L), 1 continuous-recording temperature station (M1), 25 continuous-recording temperature and conductivity stations (M2), 3 continuous-recording temperature, conductivity, and dissolved oxygen stations (M3), 13 continuous-recording temperature, conductivity, dissolved oxygen, and pH stations (M4), 5 daily chemical-quality stations (Qd), 133 periodic chemical-quality stations (Qp), 16 reservoir/lake surveys for water quality (Qs), and 70 continuous or daily reservoir-content stations (R). Plate 1 identifies the major river basins in Texas and shows the location of the stations listed in table 1.

  14. Trends in Streamflow Characteristics of Selected Sites in the Elkhorn River, Salt Creek, and Lower Platte River Basins, Eastern Nebraska, 1928-2004, and Evaluation of Streamflows in Relation to Instream-Flow Criteria, 1953-2004

    USGS Publications Warehouse

    Dietsch, Benjamin J.; Godberson, Julie A.; Steele, Gregory V.

    2009-01-01

    The Nebraska Department of Natural Resources approved instream-flow appropriations on the Platte River to maintain fish communities, whooping crane roost habitat, and wet meadows used by several wild bird species. In the lower Platte River region, the Nebraska Game and Parks Commission owns an appropriation filed to maintain streamflow for fish communities between the Platte River confluence with the Elkhorn River and the mouth of the Platte River. Because Elkhorn River flow is an integral part of the flow in the reach addressed by this appropriation, the Upper Elkhorn and Lower Elkhorn Natural Resources Districts are involved in overall management of anthropogenic effects on the availability of surface water for instream requirements. The Physical Habitat Simulation System (PHABSIM) and other estimation methodologies were used previously to determine instream requirements for Platte River biota, which led to the filing of five water appropriations applications with the Nebraska Department of Natural Resources in 1993 by the Nebraska Game and Parks Commission. One of these requested instream-flow appropriations of 3,700 cubic feet per second was for the reach from the Elkhorn River to the mouth of the Platte River. Four appropriations were granted with modifications in 1998, by the Nebraska Department of Natural Resources. Daily streamflow data for the periods of record were summarized for 17 streamflow-gaging stations in Nebraska to evaluate streamflow characteristics, including low-flow intervals for consecutive durations of 1, 3, 7, 14, 30, 60, and 183 days. Temporal trends in selected streamflow statistics were not adjusted for variability in precipitation. Results indicated significant positive temporal trends in annual flow for the period of record at eight streamflow-gaging stations - Platte River near Duncan (06774000), Platte River at North Bend (06796000), Elkhorn River at Neligh (06798500), Logan Creek near Uehling (06799500), Maple Creek near Nickerson

  15. 21. Photocopied from blueprint, Olmstead Station Miscellaneous Drawings Folder, Engineering ...

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

    21. Photocopied from blueprint, Olmstead Station Miscellaneous Drawings Folder, Engineering Department, Utah Power & Light Co., Salt Lake City, Utah. 'STATION GROUNDS, TELLURIDE POWER CO., PROVO, UTAH.' MAP,1903. - Telluride Power Company, Olmsted Hydroelectric Plant, mouth of Provo River Canyon West of U.S. Route 189, Orem, Utah County, UT

  16. Mir Space Station survey views taken during STS-76 mission

    NASA Image and Video Library

    1996-03-25

    STS076-708-031 (22 - 31 March 1996) --- Clouds over Brazil form the backdrop for this 70mm image showing the Spektr Module and other components of Russia's Mir Space Station. The photograph was taken after Space Shuttle Atlantis docked with the Mir Space Station on March 23, 1996. The delta of the giant Amazon River is at frame center.

  17. 78 FR 79434 - Sabine River Authority of Texas and Sabine River Authority, State of Louisiana; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Sabine River Authority of Texas and Sabine River Authority, State of Louisiana; Notice of Availability of the Final Environmental Impact Statement for the Toledo Bend Hydroelectric Project In accordance with the...

  18. Interaction of low-frequency axisymmetric ultrasonic guided waves with bends in pipes of arbitrary bend angle and general bend radius.

    PubMed

    Verma, Bhupesh; Mishra, Tarun Kumar; Balasubramaniam, Krishnan; Rajagopal, Prabhu

    2014-03-01

    The use of ultrasonic guided waves for the inspection of pipes with elbow and U-type bends has received much attention in recent years, but studies for more general bend angles which may also occur commonly, for example in cross-country pipes, are limited. Here, we address this topic considering a general bend angle φ, a more general mean bend radius R in terms of the wavelength of the mode studied and pipe thickness b. We use 3D Finite Element (FE) simulation to understand the propagation of fundamental axisymmetric L(0,2) mode across bends of different angles φ. The effect of the ratio of the mean bend radius to the wavelength of the mode studied, on the transmission and reflection of incident wave is also considered. The studies show that as the bend angle is reduced, a progressively larger extent of mode-conversion affects the transmission and velocity characteristics of the L(0,2) mode. However the overall message on the potential of guided waves for inspection and monitoring of bent pipes remains positive, as bends seem to impact mode transmission only to the extent of 20% even at low bend angles. The conclusions seem to be valid for different typical pipe thicknesses b and bend radii. The modeling approach is validated by experiments and discussed in light of physics of guided waves.

  19. Development of Bend Sensor for Catheter Tip

    NASA Astrophysics Data System (ADS)

    Nagano, Yoshitaka; Sano, Akihito; Fujimoto, Hideo

    Recently, a minimally invasive surgery which makes the best use of the catheter has been becoming more popular. In endovascular coil embolization for a cerebral aneurysm, the observation of the catheter's painting phenomenon is very important to execute the appropriate manipulation of the delivery wire and the catheter. In this study, the internal bend sensor which consists of at least two bending enhanced plastic optical fibers was developed in order to measure the curvature of the catheter tip. Consequently, the painting could be more sensitively detected in the neighborhood of the aneurysm. In this paper, the basic characteristics of the developed sensor system are described and its usefulness is confirmed from the comparison of the insertion force of delivery wire and the curvature of catheter tip in the experiment of coil embolization.

  20. Molecular Origin of Model Membrane Bending Rigidity

    SciTech Connect

    Kurtisovski, Erol; Taulier, Nicolas; Waks, Marcel; Ober, Raymond; Urbach, Wladimir

    2007-06-22

    The behavior of the bending modulus {kappa} of bilayers in lamellar phases was studied by Small Angle X-ray Scattering technique for various nonionic C{sub i}E{sub j} surfactants. The bilayers are either unswollen and dispersed in water or swollen by water and dispersed in dodecane. For unswollen bilayers, the values of {kappa} decrease with both an increase in the area per surfactant molecule and in the polar head length. They increase when the aliphatic chain length increases at constant area per surfactant molecule. Whereas for water-swollen membranes, the values of {kappa} decrease as the content of water increases converging to the value of the single monolayer bending modulus. Such a behavior results from the decoupling of the fluctuations of the two surfactant membrane monolayers. Our results emphasize the determinant contribution of the surfactant conformation to {kappa}.

  1. Monitoring thermoplastic composites under cyclic bending tests

    NASA Astrophysics Data System (ADS)

    Boccardi, Simone; Meola, Carosena; Carlomagno, Giovanni Maria; Simeoli, Giorgio; Acierno, Domenico; Russo, Pietro

    2016-05-01

    This work is concerned with the use of infrared thermography to visualize temperature variations linked to thermo-elastic effects developing over the surface of a specimen undergoing deflection under bending tests. Several specimens are herein considered, which involve change of matrix and/or reinforcement. More specifically, the matrix is either a pure polypropylene, or a polypropylene added with a certain percentage of compatibilizing agent; the reinforcement is made of glass, or jute. Cyclic bending tests are carried out by the aid of an electromechanical actuator. Each specimen is viewed, during deflection, from one surface by an infrared imaging device. As main finding the different specimens display surface temperature variations which depend on the type of material in terms of both matrix and reinforcement.

  2. Holey fibers for low bend loss

    NASA Astrophysics Data System (ADS)

    Nakajima, Kazuhide; Saito, Kotaro; Yamada, Yusuke; Kurokawa, Kenji; Shimizu, Tomoya; Fukai, Chisato; Matsui, Takashi

    2013-12-01

    Bending-loss insensitive fiber (BIF) has proved an essential medium for constructing the current fiber to the home (FTTH) network. By contrast, the progress that has been made on holey fiber (HF) technologies provides us with novel possibilities including non-telecom applications. In this paper, we review recent progress on hole-assisted type BIF. A simple design consideration is overviewed. We then describe some of the properties of HAF including its mechanical reliability. Finally, we introduce some applications of HAF including to high power transmission. We show that HAF with a low bending loss has the potential for use in various future optical technologies as well as in the optical communication network.

  3. Effect of confinements: Bending in Paramecium

    NASA Astrophysics Data System (ADS)

    Eddins, Aja; Yang, Sung; Spoon, Corrie; Jung, Sunghwan

    2012-02-01

    Paramecium is a unicellular eukaryote which by coordinated beating of cilia, generates metachronal waves which causes it to execute a helical trajectory. We investigate the swimming parameters of the organism in rectangular PDMS channels and try to quantify its behavior. Surprisingly a swimming Paramecium in certain width of channels executes a bend of its flexible body (and changes its direction of swimming) by generating forces using the cilia. Considering a simple model of beam constrained between two walls, we predict the bent shapes of the organism and the forces it exerts on the walls. Finally we try to explain how bending (by sensing) can occur in channels by conducting experiments in thin film of fluid and drawing analogy to swimming behavior observed in different cases.

  4. Torsion and transverse bending of cantilever plates

    NASA Technical Reports Server (NTRS)

    Reissner, Eric; Stein, Manuel

    1951-01-01

    The problem of combined bending and torsion of cantilever plates of variable thickness, such as might be considered for solid thin high-speed airplane or missile wings, is considered in this paper. The deflections of the plate are assumed to vary linearly across the chord; minimization of the potential energy by means of the calculus of variations then leads to two ordinary linear differential equations for the bending deflections and the twist of the plate. Because the cantilever is analyzed as a plate rather than as a beam, the effect of constraint against axial warping in torsion is inherently included. The application of this method to specific problems involving static deflection, vibration, and buckling of cantilever plates is presented. In the static-deflection problems, taper and sweep are considered.

  5. Vortex breakdown in simple pipe bends

    NASA Astrophysics Data System (ADS)

    Ault, Jesse; Shin, Sangwoo; Stone, Howard

    2016-11-01

    Pipe bends and elbows are one of the most common fluid mechanics elements that exists. However, despite their ubiquity and the extensive amount of research related to these common, simple geometries, unexpected complexities still remain. We show that for a range of geometries and flow conditions, these simple flows experience unexpected fluid dynamical bifurcations resembling the bubble-type vortex breakdown phenomenon. Specifically, we show with simulations and experiments that recirculation zones develop within the bends under certain conditions. As a consequence, fluid and particles can remain trapped within these structures for unexpectedly-long time scales. We also present simple techniques to mitigate this recirculation effect which can potentially have impact across industries ranging from biomedical and chemical processing to food and health sciences.

  6. Environmental Analysis of the Air Bending Process

    NASA Astrophysics Data System (ADS)

    Kellens, Karel; Dewulf, Wim; Duflou, Joost R.

    2011-05-01

    This paper presents the results of a data collection effort, allowing to assess the overall environmental impact of the air bending process using the CO2PE!-Methodology. First the different modes of the air bending process are investigated, including both productive and non-productive modes. In particular consumption of electric power is recorded for the different modes. Subsequently, time studies allow determining the importance of productive and nonproductive modes of the involved process. The study demonstrates that the influence of standby losses can be substantial. In addition to life cycle analysis, in depth process analysis also provides insight in achievable environmental impact reducing measures towards machine tool builders and eco-design recommendations for product developers. The energy consumption of three different machine tool architectures are analysed and compared within this paper.

  7. Monoclinal bending of strata over laccolithic intrusions

    USGS Publications Warehouse

    Koch, F.G.; Johnson, A.M.; Pollard, D.D.

    1981-01-01

    Sedimentary strata on top of some laccolithic intrusions are nearly horizontal and little deformed, but are bent into steeply dipping monoclinal flexures over the peripheries of these intrusions. This form of bending is not explained by previous theories of laccolithic intrusion, which predict either horizontal undeformed strata over the center and faulted strata around the periphery, or strata bent continuously into a dome. However, a slight generalization of these theories accomodates the observed form and contains the previous forms as special cases. A critical assumption is that the strength of contacts within a multilayered overburden is overcome locally by layer-parallel shear. If this strength is less than the strength of the layers themselves, then layers over the center remain bonded together and display negligible bending, whereas layers over the periphery slip over one another and are readily bent into a monoclinal flexure. ?? 1981.

  8. The Colorado River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Moderate-resolution Imaging Spectroradiometer (MODIS) true-color image shows the passage of the Colorado River through several southwestern states. The river begins, in this image, in Utah at the far upper right, where Lake Powell is visible as dark pixels surrounded by the salmon-colored rocks of the Colorado Plateau. The Colorado flows southwest through Glen Canyon, to the Glen Canyon Dam, on the Utah-Arizona border. From there it flows south into Arizona, and then turns sharply west where the Grand Canyon of the Colorado cuts through the mountains. The Colorado flows west to the Arizona-Nevada (upper left) border, where it is dammed again, this time by the Hoover Dam. The dark-colored pixels surrounding the bend in the river are Lake Mead. The river flows south along the border of first Nevada and Arizona and then California and Arizona. The Colorado River, which begins in Rocky Mountain National Park in Colorado, empties into the Gulf of California, seen at the bottom center of this image.

  9. The Colorado River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Moderate-resolution Imaging Spectroradiometer (MODIS) true-color image shows the passage of the Colorado River through several southwestern states. The river begins, in this image, in Utah at the far upper right, where Lake Powell is visible as dark pixels surrounded by the salmon-colored rocks of the Colorado Plateau. The Colorado flows southwest through Glen Canyon, to the Glen Canyon Dam, on the Utah-Arizona border. From there it flows south into Arizona, and then turns sharply west where the Grand Canyon of the Colorado cuts through the mountains. The Colorado flows west to the Arizona-Nevada (upper left) border, where it is dammed again, this time by the Hoover Dam. The dark-colored pixels surrounding the bend in the river are Lake Mead. The river flows south along the border of first Nevada and Arizona and then California and Arizona. The Colorado River, which begins in Rocky Mountain National Park in Colorado, empties into the Gulf of California, seen at the bottom center of this image.

  10. DNA Bending Stiffness on Small Length Scales

    NASA Astrophysics Data System (ADS)

    Yuan, Chongli; Chen, Huimin; Lou, Xiong Wen; Archer, Lynden A.

    2008-01-01

    Bending properties of short (15 90 bp), double-stranded DNA fragments are quantified using fluorescence resonance energy transfer and small angle x-ray scattering. Results from both types of measurements indicate that short double-stranded DNA fragments exhibit surprisingly high flexibility. These observations are discussed in terms of base-pair-level length fluctuations originating from dynamic features of Watson-Crick base pairs.

  11. Space station user's handbook

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A user's handbook for the modular space station concept is presented. The document is designed to acquaint science personnel with the overall modular space station program, the general nature and capabilities of the station itself, some of the scientific opportunities presented by the station, the general policy governing its operation, and the relationship between the program and participants from the scientific community.

  12. The multi-bend achromat storage rings

    SciTech Connect

    Eriksson, Mikael

    2016-07-27

    Not very long ago, the 3{sup rd} generation storage ring technology was judged as mature. Most of the 3{sup rd} generation storage rings used the Double-Bend Achromat (DBA) or Triple-Bend Achromat (TBA) concepts. It was however a well-known fact that increasing the number of magnet cells in the rings is a powerful way of decreasing the electron beam emittance and thus the source brilliance, but at the penalty of increasing the size and cost of the rings. Preserving the Dynamic Aperture (DA) in the rings became also an issue when increasing the number of magnet cells. The Multi-Bend Achromat (MBA) concept, including a miniaturization of the ring elements, has now drastically changed the picture. The MBA rings, now in construction or being planned, offer orders of magnitudes higher brilliance than rings of conventional designs. Several light sources around the world are now implementing or planning to implement this MBA concept. This article touches on the science drivers for higher brilliance. We will then describe the MBA concept with its advantages as well as its challenges. A short survey of the MBA activity around the world will also be presented. The author apologies for focusing on the MAX IV project regarding technical solutions. This is motivated by that MAX IV is the facility he knows best and it might be regarded as a fore-runner for the MBA concept.

  13. Forming and Bending of Metal Foams

    NASA Astrophysics Data System (ADS)

    Nebosky, Paul; Tyszka, Daniel; Niebur, Glen; Schmid, Steven

    2004-06-01

    This study examines the formability of a porous tantalum foam, known as trabecular metal (TM). Used as a bone ingrowth surface on orthopedic implants, TM is desirable due to its combination of high strength, low relative density, and excellent osteoconductive properties. This research aims to develop bend and stretch forming as a cost-effective alternative to net machining and EDM for manufacturing thin parts made of TM. Experimentally, bending about a single axis using a wiping die was studied by observing cracking and measuring springback. It was found that die radius and clearance strongly affect the springback properties of TM, while punch speed, embossings, die radius and clearance all influence cracking. Depending on the various combinations of die radius and clearance, springback factor ranged from .70-.91. To examine the affect of the foam microstructure, bending also was examined numerically using a horizontal hexagonal mesh. As the hexagonal cells were elongated along the sheet length, elastic springback decreased. This can be explained by the earlier onset of plastic hinging occurring at the vertices of the cells. While the numerical results matched the experimental results for the case of zero clearance, differences at higher clearances arose due to an imprecise characterization of the post-yield properties of tantalum. By changing the material properties of the struts, the models can be modified for use with other open-cell metallic foams.

  14. Space Station Spartan study

    NASA Technical Reports Server (NTRS)

    Lane, J. H.; Schulman, J. R.; Neupert, W. M.

    1985-01-01

    The required extension, enhancement, and upgrading of the present Spartan concept are described to conduct operations from the space station using the station's unique facilities and operational features. The space station Spartan (3S), the free flyer will be deployed from and returned to the space station and will conduct scientific missions of much longer duration than possible with the current Spartan. The potential benefits of a space station Spartan are enumerated. The objectives of the study are: (1) to develop a credible concept for a space station Spartan; and (2) to determine the associated requirements and interfaces with the space station to help ensure that the 3S can be properly accommodated.

  15. Meanderbelt Dynamics of the Sacramento River, California

    Treesearch

    Michael D. Harvey

    1989-01-01

    A 160 km-long reach of Sacramento River was studied with the objective of predicting future changes in channel planform and their effects on water-surface elevations. Planform data were used to develop regression relationships between bend radius of curvature (Rc) and both short-term (5 years) and long term (90 years) lateral migration rates (MR) and migration...

  16. 76 FR 81992 - PPL Bell Bend, LLC; Combined License Application for Bell Bend Nuclear Power Plant; Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION PPL Bell Bend, LLC; Combined License Application for Bell Bend Nuclear Power Plant; Exemption 1.0..., Certifications, and Approvals for Nuclear Power Plants.'' This reactor is to be identified as Bell Bend...

  17. 78 FR 4465 - PPL Bell Bend, LLC; Combined License Application for Bell Bend Nuclear Power Plant; Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-22

    ... COMMISSION PPL Bell Bend, LLC; Combined License Application for Bell Bend Nuclear Power Plant; Exemption 1.0... Approvals for Nuclear Power Plants.'' This reactor is to be identified as Bell Bend Nuclear Power Plant... (RCOL) application for UniStar's Calvert Cliffs Nuclear Power Plant, Unit 3 (CCNPP3). The NRC is...

  18. THE STRUCTURAL BASIS OF CILIARY BEND FORMATION

    PubMed Central

    Warner, Fred D.; Satir, Peter

    1974-01-01

    The sliding microtubule model of ciliary motility predicts that cumulative local displacement (Δl) of doublet microtubules relative to one another occurs only in bent regions of the axoneme. We have now tested this prediction by using the radial spokes which join the A subfiber of each doublet to the central sheath as markers of microtubule alignment to measure sliding displacements directly. Gill cilia from the mussel Elliptio complanatus have radial spokes lying in groups of three which repeat at 860 Å along the A subfiber. The spokes are aligned with the two rows of projections along each of the central microtubules that form the central sheath. The projections repeat at 143 Å and form a vernier with the radial spokes in the precise ratio of 6 projection repeats to 1 spoke group repeat. In straight regions of the axoneme, either proximal or distal to a bend, the relative position of spoke groups between any two doublets remains constant for the length of that region. However, in bent regions, the position of spoke groups changes systematically so that Δl (doublet 1 vs. 5) can be seen to accumulate at a maximum of 122 Å per successive 860-Å spoke repeat. Local contraction of microtubules is absent. In straight regions of the axoneme, the radial spokes lie in either of two basic configurations: (a) the parallel configuration where spokes 1–3 of each group are normal (90°) to subfiber A, and (b) the tilted spoke 3 configuration where spoke 3 forms an angle (θ) of 9–20°. Since considerable sliding of doublets relative to the central sheath (∼650 Å) has usually occurred in these regions, the spokes must be considered, functionally, as detached from the sheath projections. In bent regions of the axoneme, two additional spoke configurations occur where all three spokes of each group are tilted to a maximum of ± 33° from normal. Since the spoke angles do not lie on radii through the center of bend curvature, and Δl accumulates in the bend, the spokes

  19. Permanent bending and alignment of ZnO nanowires.

    PubMed

    Borschel, Christian; Spindler, Susann; Lerose, Damiana; Bochmann, Arne; Christiansen, Silke H; Nietzsche, Sandor; Oertel, Michael; Ronning, Carsten

    2011-05-06

    Ion beams can be used to permanently bend and re-align nanowires after growth. We have irradiated ZnO nanowires with energetic ions, achieving bending and alignment in different directions. Not only the bending of single nanowires is studied in detail, but also the simultaneous alignment of large ensembles of ZnO nanowires. Computer simulations reveal how the bending is initiated by ion beam induced damage. Detailed structural characterization identifies dislocations to relax stresses and make the bending and alignment permanent, even surviving annealing procedures.

  20. Tunable waveguide bends with graphene-based anisotropic metamaterials

    NASA Astrophysics Data System (ADS)

    Chen, Zhao-xian; Chen, Ze-guo; Ming, Yang; Wu, Ying; Lu, Yan-qing

    2016-02-01

    We design tunable waveguide bends filled with graphene-based anisotropic metamaterials to achieve a nearly perfect bending effect. The anisotropic properties of the metamaterials can be described by the effective medium theory. The nearly perfect bending effect is demonstrated by finite element simulations of various structures with different bending curvatures and shapes. This effect is attributed to zero effective permittivity along the direction of propagation and matched effective impedance at the interfaces between the bending part and the dielectric waveguides. We envisage that the design will be applicable in the far-infrared and terahertz frequency ranges owing to the tunable dielectric responses of graphene.

  1. Recent developments in bend-insensitive and ultra-bend-insensitive fibers

    NASA Astrophysics Data System (ADS)

    Boivin, David; de Montmorillon, Louis-Anne; Provost, Lionel; Montaigne, Nelly; Gooijer, Frans; Aldea, Eugen; Jensma, Jaap; Sillard, Pierre

    2010-02-01

    Designed to overcome the limitations in case of extreme bending conditions, Bend- and Ultra-Bend-Insensitive Fibers (BIFs and UBIFs) appear as ideal solutions for use in FTTH networks and in components, pigtails or patch-cords for ever demanding applications such as military or sensing. Recently, however, questions have been raised concerning the Multi-Path-Interference (MPI) levels in these fibers. Indeed, they are potentially subject to interferences between the fundamental mode and the higher-order mode that is also bend resistant. This MPI is generated because of discrete discontinuities such as staples, bends and splices/connections that occur on distance scales that become comparable to the laser coherent length. In this paper, we will demonstrate the high MPI tolerance of all-solid single-trench-assisted BIFs and UBIFs. We will present the first comprehensive study combining theoretical and experimental points of view to quantify the impact of fusion splices on coherent MPI. To be complete, results for mechanical splices will also be reported. Finally, we will show how the single-trench- assisted concept combined with the versatile PCVD process allows to tightly control the distributions of fibers characteristics. Such controls are needed to massively produce BIFs and to meet the more stringent specifications of the UBIFs.

  2. Missouri River Environmental Inventory. Measurements of the Species Diversity of Planktonic and Microbenthic Organisms.

    DTIC Science & Technology

    1973-01-01

    protozoan species in the benthos of the unchannelized river were found to be the ciliate Paramecium aurelia and the flagelleted species of the genus...the ciliate Vorticella and the ciliate Paramecium aurelia were found to be the most dominant. Or. the basis of total numbers, the plankton was...the benthos at Synder Bend or DeSoto Bend Oxbows during the spring months. The dominant ciliates in the plankton at Synder Bend Oxbow were Paramecium

  3. Driven around the bend: Spatial evolution and controls on the orientation of helical bend flow in a natural submarine gravity current

    NASA Astrophysics Data System (ADS)

    Sumner, E. J.; Peakall, J.; Dorrell, R. M.; Parsons, D. R.; Darby, S. E.; Wynn, R. B.; McPhail, S. D.; Perrett, J.; Webb, A.; White, D.

    2014-02-01

    Submarine channel systems transport vast amounts of terrestrial sediment into the deep sea. Understanding the dynamics of the gravity currents that create these systems, and in particular, how these flows interact with and form bends, is fundamental to predicting system architecture and evolution. Bend flow is characterized by a helical structure and in rivers typically comprises inwardly directed near-bed flow and outwardly directed near-surface flow. Following a decade of debate, it is now accepted that helical flow in submarine channel bends can exhibit a variety of structures including being opposed to that observed in rivers. The new challenge is to understand what controls the orientation of helical flow cells within submarine flows and determines the conditions for reversal. We present data from the Black Sea showing, for the first time, the three-dimensional velocity and density structure of an active submarine gravity current. By calculating the forces acting on the flow, we evaluate what controls the orientation of helical flow cells. We demonstrate that radial pressure gradients caused by across-channel stratification of the flow are more important than centrifugal acceleration in controlling the orientation of helical flow. We also demonstrate that nonlocal acceleration of the flow due to topographic forcing and downstream advection of the cross-stream flow are significant terms in the momentum balance. These findings have major implications for conceptual and numerical models of submarine channel dynamics, because they show that three-dimensional models that incorporate across-channel flow stratification are required to accurately represent curvature-induced helical flow in such systems.

  4. Driven around the bend: Spatial evolution and controls on the orientation of helical bend flow in a natural submarine gravity current

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Submarine channel systems transport vast amounts of terrestrial sediment into the deep sea. Understanding the dynamics of the gravity currents that create these systems, and in particular, how these flows interact with and form bends, is fundamental to predicting system architecture and evolution. Bend flow is characterized by a helical structure and in rivers typically comprises inwardly directed near-bed flow and outwardly directed near-surface flow. Following a decade of debate, it is now accepted that helical flow in submarine channel bends can exhibit a variety of structures including being opposed to that observed in rivers. The new challenge is to understand what controls the orientation of helical flow cells within submarine flows and determines the conditions for reversal. We present data from the Black Sea showing, for the first time, the three-dimensional velocity and density structure of an active submarine gravity current. By calculating the forces acting on the flow, we evaluate what controls the orientation of helical flow cells. We demonstrate that radial pressure gradients caused by across-channel stratification of the flow are more important than centrifugal acceleration in controlling the orientation of helical flow. We also demonstrate that nonlocal acceleration of the flow due to topographic forcing and downstream advection of the cross-stream flow are significant terms in the momentum balance. These findings have major implications for conceptual and numerical models of submarine channel dynamics, because they show that three-dimensional models that incorporate across-channel flow stratification are required to accurately represent curvature-induced helical flow in such systems.

  5. Representation of horizontal strain due to tidal bending by observation and modeling

    NASA Astrophysics Data System (ADS)

    Rack, Wolfgang; King, Matt; Marsh, Oliver; Wild, Christian; Floricioiu, Dana

    2017-04-01

    An important control of ice sheet mass balance is the ice dynamics in the grounding zones around Antarctica. On many outflow glaciers a large temporal variability in ice flow has been observed, which is at least partly related to tides. Here we investigate the tide induced short term ice deformation in an ice shelf grounding zone and the related bending stresses and strain. We make use of the arguably most precise measurement method, differential SAR interferometry, in combination with ground based measurements and model assumptions for tidal bending. Ground validation and satellite data have been acquired within a dedicated field campaign. The Southern McMurdo Ice Shelf in the Western Ross Ice Shelf region was chosen as the experiment site. This area is optimal for the data interpretation because of a simple grounding line configuration, small ice flux, and favourable satellite imaging geometry. It is also a safe area which allowed the installation of tiltmeters and GPS stations, and glaciological measurements such as ice thickness and snow accumulation. From November 2014 to January 2015 the tidal movement was recorded over a period of 2.5 months. TerrSAR-X radar images have been acquired over the same period as a basis to derive ice shelf flexure maps. Despite the viscoelastic effects in ice shelf bending a simple elastic bending model for a beam of finite ice thickness can largely explain the GPS-observed surface strain. Using the same model and taking into account the viewing geometry of the satellite radar, it is now possible to separate horizontal and vertical displacement components in the satellite data. As a result we can obtain more realistic ice shelf flexure profiles from the interferometric SAR measurement. The newly derived flexure profiles are therefore more suitable to recover viscoelastic effects of tidal bending in grounding zones of ice shelves and outlet glaciers. These effects would have otherwise remained unnoticed.

  6. Characterization of bending loss in hollow flexible terahertz waveguides.

    PubMed

    Doradla, Pallavi; Joseph, Cecil S; Kumar, Jayant; Giles, Robert H

    2012-08-13

    Attenuation characteristics of hollow, flexible, metal and metal/dielectric coated polycarbonate waveguides were investigated using an optically pumped far infrared (FIR) laser at 215 µm. The bending loss of silver coated polycarbonate waveguides were measured as a function of various bending angles, bending radii, and bore diameters. Minimal propagation losses of 1.77, 0.96 dB/m were achieved by coupling the lowest loss TE11 mode into the silver or gold coated waveguide, and HE11 mode into the silver/polystyrene coated waveguides respectively. The maximal bending loss was found to be less than 1 dB/m for waveguides of 2 to 4.1 mm bore diameters, with a 6.4 cm bend radius, and up to 150° bending angle. The investigation shows the preservation of single laser mode in smaller bore waveguides even at greater bending angles.

  7. A study on springback of bending linear flow split profiles

    NASA Astrophysics Data System (ADS)

    Mahajan, P.; Taplick, C.; Özel, M.; Groche, P.

    2016-11-01

    The bending of linear flow split profiles made up of high strength materials involves high bending loads leading to high springback and geometrical defects. In addition, the linear flow split profiles are made stronger due to the high plastic deformation applied by the process itself. The bending method proposed in this paper combines the linear flow splitting process with a movable bending tool. The aim of the research was to investigate the effect of superimposed stresses exerted by the linear flow splitting process on bending load and springback of the profile by using a finite element model. The latter was validated by means of experimental results. The results show that the bending loads and the springback were reduced by increasing the superposition of stress applied by the linear flow splitting process. The reduction in the bending loads leads to a reduction in the cross-sectional distortion. Furthermore, the springback was compensated by controlling the amount of superimposed stress.

  8. Internal connectivity of meandering rivers: Statistical generalization of channel hydraulic geometry

    NASA Astrophysics Data System (ADS)

    Czapiga, M. J.; Smith, V. B.; Nittrouer, J. A.; Mohrig, D.; Parker, G.

    2015-09-01

    The geometry of rivers has been characterized in terms of downstream and at-a-station hydraulic geometry, based on individual cross sections. Such analyses do not, however, provide insight as to how these cross sections are connected. We generalize the concept of hydraulic geometry, using data on bathymetry from four reaches of meandering rivers that include at least five bends. We quantify connectivity in terms of the probability that a connected path exists such that a given attribute remains within specified bounds along it. While the concept is general, here we apply it to vessel navigability. We develop a predictor for navigability in meandering rivers, which requires only the following, relatively easily obtained input: vessel draft, vessel width, bankfull depth, bankfull width, relative difference between current and bankfull water surface elevation, and length of desired navigation path. The predictor is applicable to both bankfull and below-bankfull stage. A key input parameter is the standard deviation of the probability distribution of depth. This parameter, in and of itself, yields no information on connectivity as it does not capture the spatial orientation of depth variation. We find, however, that (a) the probability function for connectivity does depend on this parameter, and (b) its use allows for an approximate similarity collapse of the probability function, so providing a quasi-universal predictive relation applying to all four reaches. The results also suggest potential application to more complex forms for connectivity that involve other or multiple in-stream physical variables.

  9. Database for the geologic map of the Bend 30- x 60-minute quadrangle, central Oregon

    USGS Publications Warehouse

    Koch, Richard D.; Ramsey, David W.; Sherrod, David R.; Taylor, Edward M.; Ferns, Mark L.; Scott, William E.; Conrey, Richard M.; Smith, Gary A.

    2010-01-01

    The Bend 30- x 60-minute quadrangle has been the locus of volcanism, faulting, and sedimentation for the past 35 million years. It encompasses parts of the Cascade Range and Blue Mountain geomorphic provinces, stretching from snowclad Quaternary stratovolcanoes on the west to bare rocky hills and sparsely forested juniper plains on the east. The Deschutes River and its large tributaries, the Metolius and Crooked Rivers, drain the area. Topographic relief ranges from 3,157 m (10,358 ft) at the top of South Sister to 590 m (1,940 ft) at the floor of the Deschutes and Crooked Rivers where they exit the area at the north-central edge of the map area. The map encompasses a part of rapidly growing Deschutes County. The city of Bend, which has over 70,000 people living in its urban growth boundary, lies at the south-central edge of the map. Redmond, Sisters, and a few smaller villages lie scattered along the major transportation routes of U.S. Highways 97 and 20. This geologic map depicts the geologic setting as a basis for structural and stratigraphic analysis of the Deschutes basin, a major hydrologic discharge area on the east flank of the Cascade Range. The map also provides a framework for studying potentially active faults of the Sisters fault zone, which trends northwest across the map area from Bend to beyond Sisters. This digital release contains all of the information used to produce the geologic map published as U.S. Geological Survey Geologic Investigations Series I-2683 (Sherrod and others, 2004). The main component of this digital release is a geologic map database prepared using ArcInfo GIS. This release also contains files to view or print the geologic map and accompanying descriptive pamphlet from I-2683.

  10. Cricket antennae shorten when bending (Acheta domesticus L.).

    PubMed

    Loudon, Catherine; Bustamante, Jorge; Kellogg, Derek W

    2014-01-01

    Insect antennae are important mechanosensory and chemosensory organs. Insect appendages, such as antennae, are encased in a cuticular exoskeleton and are thought to bend only between segments or subsegments where the cuticle is thinner, more flexible, or bent into a fold. There is a growing appreciation of the dominating influence of folds in the mechanical behavior of a structure, and the bending of cricket antennae was considered in this context. Antennae will bend or deflect in response to forces, and the resulting bending behavior will affect the sensory input of the antennae. In some cricket antennae, such as in those of Acheta domesticus, there are a large number (>100) of subsegments (flagellomeres) that vary in their length. We evaluated whether these antennae bend only at the joints between flagellomeres, which has always been assumed but not tested. In addition we questioned whether an antenna undergoes a length change as it bends, which would result from some patterns of joint deformation. Measurements using light microscopy and SEM were conducted on both male and female adult crickets (Acheta domesticus) with bending in four different directions: dorsal, ventral, medial, and lateral. Bending occurred only at the joints between flagellomeres, and antennae shortened a comparable amount during bending, regardless of sex or bending direction. The cuticular folds separating antennal flagellomeres are not very deep, and therefore as an antenna bends, the convex side (in tension) does not have a lot of slack cuticle to "unfold" and does not lengthen during bending. Simultaneously on the other side of the antenna, on the concave side in compression, there is an increasing overlap in the folded cuticle of the joints during bending. Antennal shortening during bending would prevent stretching of antennal nerves and may promote hemolymph exchange between the antenna and head.

  11. Evolving efficiency of restraining bends within wet kaolin analog experiments

    NASA Astrophysics Data System (ADS)

    Hatem, Alexandra E.; Cooke, Michele L.; Madden, Elizabeth H.

    2015-03-01

    Restraining bends along strike-slip fault systems evolve by both propagation of new faults and abandonment of fault segments. Scaled analog modeling using wet kaolin allows for qualitative and quantitative observations of this evolution. To explore how bend geometry affects evolution, we model bends with a variety of initial angles, θ, from θ = 0° for a straight fault to θ = 30°. High-angle restraining bends (θ ≥ 20°) overcome initial inefficiencies by abandoning unfavorably oriented restraining segments and propagating multiple new, inwardly dipping, oblique-slip faults that are well oriented to accommodate convergence within the bend. Restraining bends with 0° < θ ≤ 15° maintain activity along the restraining bend segment and grow a single new oblique slip fault on one side of the bend. In all restraining bends, the first new fault propagates at ~5 mm of accumulated convergence. Particle Image Velocimetry analysis provides a complete velocity field throughout the experiments. From these data, we quantify the strike-slip efficiency of the system as the percentage of applied plate-parallel velocity accommodated as slip in the direction of plate motion along faults within the restraining bend. Bends with small θ initially have higher strike-slip efficiency compared to bends with large θ. Although they have different fault geometries, all systems with a 5 cm bend width reach a steady strike-slip efficiency of 80% after 50 mm of applied plate displacement. These experimental restraining bends resemble crustal faults in their asymmetric fault growth, asymmetric topographic gradient, and strike-slip efficiency.

  12. Cricket antennae shorten when bending (Acheta domesticus L.)

    PubMed Central

    Loudon, Catherine; Bustamante, Jorge; Kellogg, Derek W.

    2014-01-01

    Insect antennae are important mechanosensory and chemosensory organs. Insect appendages, such as antennae, are encased in a cuticular exoskeleton and are thought to bend only between segments or subsegments where the cuticle is thinner, more flexible, or bent into a fold. There is a growing appreciation of the dominating influence of folds in the mechanical behavior of a structure, and the bending of cricket antennae was considered in this context. Antennae will bend or deflect in response to forces, and the resulting bending behavior will affect the sensory input of the antennae. In some cricket antennae, such as in those of Acheta domesticus, there are a large number (>100) of subsegments (flagellomeres) that vary in their length. We evaluated whether these antennae bend only at the joints between flagellomeres, which has always been assumed but not tested. In addition we questioned whether an antenna undergoes a length change as it bends, which would result from some patterns of joint deformation. Measurements using light microscopy and SEM were conducted on both male and female adult crickets (Acheta domesticus) with bending in four different directions: dorsal, ventral, medial, and lateral. Bending occurred only at the joints between flagellomeres, and antennae shortened a comparable amount during bending, regardless of sex or bending direction. The cuticular folds separating antennal flagellomeres are not very deep, and therefore as an antenna bends, the convex side (in tension) does not have a lot of slack cuticle to “unfold” and does not lengthen during bending. Simultaneously on the other side of the antenna, on the concave side in compression, there is an increasing overlap in the folded cuticle of the joints during bending. Antennal shortening during bending would prevent stretching of antennal nerves and may promote hemolymph exchange between the antenna and head. PMID:25018734

  13. 76 FR 56638 - Safety Zone; Head of the Cuyahoga, Cuyahoga River, Cleveland, OH

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... 41.29'19'' N, 81.40'50'' W (Marathon Bend) to a line drawn perpendicular to each river bank at 41.29... perpendicular to each riverbank at 41.29'19'' N, 81.40'50'' W (Marathon Bend) to a line drawn perpendicular to...

  14. The Dependency of Nematic and Twist-bend Mesophase Formation on Bend Angle

    PubMed Central

    Mandle, Richard J.; Archbold, Craig T.; Sarju, Julia P.; Andrews, Jessica L.; Goodby, John W.

    2016-01-01

    We have prepared and studied a family of cyanobiphenyl dimers with varying linking groups with a view to exploring how molecular structure dictates the stability of the nematic and twist-bend nematic mesophases. Using molecular modelling and 1D 1H NOESY NMR spectroscopy, we determine the angle between the two aromatic core units for each dimer and find a strong dependency of the stability of both the nematic and twist-bend mesophases upon this angle, thereby satisfying earlier theoretical models. PMID:27819300

  15. COMPARISON OF DOUBLE BEND AND TRIPLE BEND ACHROMATIC LATTICE STRUCTURES AND NSLS-II.

    SciTech Connect

    KRAMER, S.L.; KRINSKY, S.; BENGTSSON, J.

    2006-06-26

    The Double Bend Achromatic (DBA) and the Triple Bend Achromatic (TBA) lattice have been studied rather extensively for use for the NSLS-II storage ring. The advantage of the TBA compared to the DBA in terms of emittance per period is well known. However, the DBA has the advantage of greater number of ID straight sections for the users and maybe easier to tune the dispersive section for reduced chromatic sextupole strength. We present a comparison of these lattices based on optimization of the non-linear driving terms using high order achromatic cancellation of driving terms of the nonlinear lattice.

  16. Investigation of load effect on macro-bend losses for an SMS fiber structure with a small bend radius

    NASA Astrophysics Data System (ADS)

    Rahmah, Fitri; Sekartedjo, Sekartedjo; Hatta, Agus Muhamad

    2016-11-01

    Modelling of load effect on macro-bend losses for a singlemode-multimode-singlemode (SMS) fiber structure with small bend radius is presented. Load effect on macro-bend losses for the SMS fiber structure placed between two high-density polyethylene (HDPE) boards are investigated theoretically and experimentally. A model on macro-bend losses for SMS fiber structure is constructed by using the light transmission formula in a straight SMS fiber structure and taking into account the effective number of guided modes due to the macrobending. In the experimental, a mandrel with a diameter of 0.8 mm is used to induce the bend. When the loads are applied on the system, the mandrel will affect the bend losses for the SMS fiber structure. It is shown numerically and experimentally that the bend-loss of SMS fiber structure strongly depends on the applied loads and the multimode fiber (MMF) lengths.

  17. 23. Station Compressor Room 1 with Air Compressors and Accumulator ...

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

    23. Station Compressor Room 1 with Air Compressors and Accumulator Tanks, view to the south. One of the two large station air compressor units used for depressing the draft tube water level is visible atop a concrete pedestal on the left side of photograph (the second identical compressor is located in an adjacent room). Two of the six station air accumulator tanks are visible in the background. The smaller station service air compressor is visible in right foreground of the photograph was installed in the early 1980s, and replaced the original station service air compressor. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

  18. Broadband light bending with plasmonic nanoantennas.

    PubMed

    Ni, Xingjie; Emani, Naresh K; Kildishev, Alexander V; Boltasseva, Alexandra; Shalaev, Vladimir M

    2012-01-27

    The precise manipulation of a propagating wave using phase control is a fundamental building block of optical systems. The wavefront of a light beam propagating across an interface can be modified arbitrarily by introducing abrupt phase changes. We experimentally demonstrated unparalleled wavefront control in a broadband optical wavelength range from 1.0 to 1.9 micrometers. This is accomplished by using an extremely thin plasmonic layer (~λ/50) consisting of an optical nanoantenna array that provides subwavelength phase manipulation on light propagating across the interface. Anomalous light-bending phenomena, including negative angles of refraction and reflection, are observed in the operational wavelength range.

  19. Light-bending tests of Lorentz invariance

    SciTech Connect

    Tso, Rhondale; Bailey, Quentin G.

    2011-10-15

    Classical light-bending is investigated for weak gravitational fields in the presence of hypothetical local Lorentz violation. Using an effective field theory framework that describes general deviations from local Lorentz invariance, we derive a modified deflection angle for light passing near a massive body. The results include anisotropic effects not present for spherical sources in General Relativity as well as Weak Equivalence Principle violation. We develop an expression for the relative deflection of two distant stars that can be used to analyze data in past and future solar-system observations. The measurement sensitivities of such tests to coefficients for Lorentz violation are discussed.

  20. Bending of light in quantum gravity.

    PubMed

    Bjerrum-Bohr, N E J; Donoghue, John F; Holstein, Barry R; Planté, Ludovic; Vanhove, Pierre

    2015-02-13

    We consider the scattering of lightlike matter in the presence of a heavy scalar object (such as the Sun or a Schwarzschild black hole). By treating general relativity as an effective field theory we directly compute the nonanalytic components of the one-loop gravitational amplitude for the scattering of massless scalars or photons from an external massive scalar field. These results allow a semiclassical computation of the bending angle for light rays grazing the Sun, including long-range ℏ contributions. We discuss implications of this computation, in particular, the violation of some classical formulations of the equivalence principle.

  1. Mixed-Mode-Bending Delamination Apparatus

    NASA Technical Reports Server (NTRS)

    Crews, John H., Jr.; Reeder, James R.

    1991-01-01

    Mixed-mode-bending delamination apparatus generates two types of delamination stress simultaneously in specimen from single externally applied point load. In technique, indivial mode I and mode II contributions to delamination in specimen analyzed by use of simple beam-theory equations, eliminating need for time-consuming, difficult numerical analysis. Allows wider range of mode I/mode II ratios than possible with many other methods. Mixed-mode delamination testing of interest in all fields utilizing composite materials, used mostly in aerospace field, but also used in automobiles, lightweight armored military vehicles, boats, and sporting equipment. Useful in general lumber, plywood, and adhesive industries, as well.

  2. Thermoelastic bending of locally heated orthotropic shells

    NASA Astrophysics Data System (ADS)

    Shevchenko, V. P.; Gol'tsev, A. S.

    2007-03-01

    The thermoelastic bending of locally heated orthotropic shells is studied using the classical theory of thermoelasticity of thin shallow orthotropic shells and the method of fundamental solutions. Linear distribution of temperature over thickness and the Newton's law of cooling are assumed. Numerical analysis is carried out for orthotropic shells of arbitrary Gaussian curvature made of a strongly anisotropic material. The behavior of thermal forces and moments near the zone of local heating is studied for two areas of thermal effect: along a coordinate axis and along a circle of unit radius. Generalized conclusions are drawn

  3. Self-bending symmetric cusp beams

    SciTech Connect

    Gong, Lei; Liu, Wei-Wei; Lu, Yao; Li, Yin-Mei; Ren, Yu-Xuan

    2015-12-07

    A type of self-bending symmetric cusp beams with four accelerating intensity maxima is theoretically and experimentally presented. Distinguished from the reported regular polygon beams, the symmetric cusp beams simultaneously exhibit peculiar features of natural autofocusing and self-acceleration during propagation. Further, such beams take the shape of a fine longitudinal needle-like structure at the focal region and possess the strong ability of self-healing over obstacles. All these intriguing properties were verified experimentally. Particularly, the spatial profile of the reconstructed beam exhibits spatially sculpted optical structure with four siamesed curved arms. Thus, we anticipate that the structured beam will benefit optical guiding and optofluidics in surprising ways.

  4. MHD bending waves in a current sheet

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.; Suess, S. T.

    1986-01-01

    Transverse MHD bending waves are considered in an isothermal and compressible two-dimensional current sheet of finite thickness in which the magnetic field changes direction and strength. The general form of the wave equation is obtained. It is shown that rotation of the magnetic field across the current sheet prevents the existence of singular points so that continuous spectrum solutions and the concomitant wave decay disappear. Instead, normal modes exist and closed integral solution for arbitrary current sheet structure are found. The results are discussed in terms of small-scale waves on the heliospheric current sheet.

  5. Great Bend tornadoes of August 30, 1974

    NASA Technical Reports Server (NTRS)

    Umenhofer, T. A.; Fujita, T. T.; Dundas, R.

    1977-01-01

    Photogrammetric analyses of movies and still pictures taken of the Great Bend, Kansas Tornado series have been used to develop design specifications for nuclear power plants and facilities. A maximum tangential velocity of 57 m/sec and a maximum vertical velocity of 27 m/sec are determined for one suction vortex having a translational velocity of 32 m/sec. Three suction vortices with radii in the 20 to 30 m range are noted in the flow field of one tornado; these suction vortices apparently form a local convergence of inflow air inside the outer portion of the tornado core.

  6. Great Bend tornadoes of August 30, 1974

    NASA Technical Reports Server (NTRS)

    Umenhofer, T. A.; Fujita, T. T.; Dundas, R.

    1977-01-01

    Photogrammetric analyses of movies and still pictures taken of the Great Bend, Kansas Tornado series have been used to develop design specifications for nuclear power plants and facilities. A maximum tangential velocity of 57 m/sec and a maximum vertical velocity of 27 m/sec are determined for one suction vortex having a translational velocity of 32 m/sec. Three suction vortices with radii in the 20 to 30 m range are noted in the flow field of one tornado; these suction vortices apparently form a local convergence of inflow air inside the outer portion of the tornado core.

  7. Anomalous bending effect in photonic crystal fibers.

    PubMed

    Tu, Haohua; Jiang, Zhi; Marks, Daniel L; Boppart, Stephen A

    2008-04-14

    An unexpected transmission loss up to 50% occurs to intense femtosecond pulses propagating along an endlessly single-mode photonic crystal fiber over a length of 1 m. A specific leaky-fiber mode gains amplification along the fiber at the expense of the fundamental fiber mode through stimulated four-wave mixing and Raman scattering, leading to this transmission loss. Bending near the fiber entrance dissipates the propagating seed of this leaky mode, preventing the leaky mode amplification and therefore enhancing the transmission of these pulses.

  8. On the characteristics and scales of outer bank roughness on large meander bends: the influence of bank material properties, floodplain vegetation and flow inundation

    USDA-ARS?s Scientific Manuscript database

    This paper explores the scales and characteristics of form roughness along the outer banks of two bends on a large meandering river through investigation of irregularities in bank contours and local topographic variability on the bank face. The analysis also examines how roughness varies over the ve...

  9. Rawhide Energy Station, Fort Collins, Colorado

    SciTech Connect

    Peltier, R.

    2008-10-15

    The staff of Platte River Power Authority's Rawhide Energy Station have been racking up operating stats and an environmental performance record that is the envy of other plant managers. In the past decade Rawhide has enjoyed an equivalent availability factor in the mid to high 90s and an average capacity factor approaching 90%. Still not content with this performance, Rawhide invested in new technology and equipment upgrades to further optimise performance, reduce emissions, and keep cost competitive. The Energy Station includes four GE France 7EA natural gas-fired turbines totalling 260 MW and a 274 MW coal-fired unit located in northeastern Colorado. 7 figs.

  10. 47 CFR 73.877 - Station logs for LPFM stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Station logs for LPFM stations. 73.877 Section... BROADCAST SERVICES Low Power FM Broadcast Stations (LPFM) § 73.877 Station logs for LPFM stations. The licensee of each LPFM station must maintain a station log. Each log entry must include the time and date...

  11. 47 CFR 73.877 - Station logs for LPFM stations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Station logs for LPFM stations. 73.877 Section... BROADCAST SERVICES Low Power FM Broadcast Stations (LPFM) § 73.877 Station logs for LPFM stations. The licensee of each LPFM station must maintain a station log. Each log entry must include the time and date...

  12. 47 CFR 73.877 - Station logs for LPFM stations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Station logs for LPFM stations. 73.877 Section... BROADCAST SERVICES Low Power FM Broadcast Stations (LPFM) § 73.877 Station logs for LPFM stations. The licensee of each LPFM station must maintain a station log. Each log entry must include the time and date...

  13. 47 CFR 73.877 - Station logs for LPFM stations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Station logs for LPFM stations. 73.877 Section... BROADCAST SERVICES Low Power FM Broadcast Stations (LPFM) § 73.877 Station logs for LPFM stations. The licensee of each LPFM station must maintain a station log. Each log entry must include the time and date...

  14. 47 CFR 73.877 - Station logs for LPFM stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Station logs for LPFM stations. 73.877 Section... BROADCAST SERVICES Low Power FM Broadcast Stations (LPFM) § 73.877 Station logs for LPFM stations. The licensee of each LPFM station must maintain a station log. Each log entry must include the time and date...

  15. The Danube Bend, Hungary - proposal for its recognition as a geoheritage

    NASA Astrophysics Data System (ADS)

    Karátson, Dávid

    2016-04-01

    The Danube Bend in North Hungary is a river curvature along the Danube river, cut into a rocky section that reveals Miocene volcanic sucessions. The deepest and narrowest part of the curvature, 5 km in diameter (called Visegrád Gorge), is one of the most picturesque landscapes in Hungary. There, the Danube, before changing its direction toward the south, forms a U-shaped valley in planform - a peculiar shape that has been an enigmatic issue in Hungarian earth sciences since the 19th century. A number of geomorphological theories have been put forward for the origin of the valley, which is incised between remnants of ca. 16 Ma old, small-sized dacitic stratovolcanoes of the Börzsöny Mts to the north, and the ~15 Ma Keserűs Hill lava dome complex to the south, all of which emerged in a contemporaneous archipelago (existent up to Pannonian times). According to Karátson et al. (2006), the U-shaped loop is partly inherited from a late-stage horseshoe caldera morphology of Keserűs Hill volcano, open to the north. Several Ma later, the formation of the Danube Bend was initiated by river incision, removing the post-volcanic sedimentary cover in mid- or rather, late Pleistocene times. Fluvial processes and erosion in turn were triggered by mountain uplift, climate changes, and drop of remote erosion base level. The present curvature of the river was controlled by the exhumation of the horseshoe caldera as well as the surrounding resistant volcaniclastic rocks (e.g. Visegrád Castle Hill) and a hilltop lava dome (Szent Mihály Hill). Moreover, an early-stage meander of Danube may have also inherited. The accelerated Late Quaternary erosion and intense dissection has resulted in a "re-birth" of the volcanic relief, which exhibits again steep slopes to form the spectacular gorge. At present, exposed rock formations (e.g. Vadálló-kövek) tower above the Danube Bend, making the area one of the most scenic landscape in East-Central Europe. Therefore, in 1997, the Danube

  16. Station Tour: Russian Segment

    NASA Image and Video Library

    Expedition 33 Commander Suni Williams concludes her tour of the International Space Station with a visit to the Russian segment, which includes Zarya, the first segment of the station launched in 1...

  17. River meanders

    USGS Publications Warehouse

    Leopold, Luna Bergere; Langbein, Walter Basil

    1966-01-01

    The striking geometric regularity of a winding river is no accident. Meanders appear to be the form in which a river does the least work in turning; hence they are the most probable form a river can take

  18. Radio spectrum surveillance station

    NASA Technical Reports Server (NTRS)

    Hersey, D. R.

    1979-01-01

    The paper presents a general and functional description of a low-cost surveillance station designed as the first phase of NASA's program to develop a radio spectrum surveillance capability for deep space stations for identifying radio frequency interference sources. The station described has identified several particular interferences and is yielding spectral signature data which, after cataloging, will serve as a library for rapid identification of frequently observed interference. Findings from the use of the station are discussed.

  19. Guided Wave Travel Time Tomography for Bends

    NASA Astrophysics Data System (ADS)

    Volker, Arno; Bloom, Joost

    2011-06-01

    The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation is an interesting addition to the current method of periodic inspections. Guided wave tomography has been developed to map the wall thickness using the travel times of guided waves. The method has been demonstrated for straight pipes. The extension of this method to bends is not straightforward because natural focusing occurs due to geometrical path differences. This yields a phase jump, which complicates travel time picking. Because ray-tracing is no longer sufficient to predict the travel times a recursive wave field extrapolation has been developed. The method uses a short spatial convolution operator to propagate a wave field through a bend. The method allows to calculate the wave field at the detector ring, including the phase jump as a consequence of the natural focusing. The recursive wave field extrapolation is done in the space-frequency domain. Therefore dispersion effects can be included easily in the forward modeling. Comparison with measurements shows the accuracy of the method.

  20. International Space Station (ISS)

    NASA Image and Video Library

    1997-07-20

    Photograph shows the International Space Station Laboratory Module under fabrication at Marshall Space Flight Center (MSFC), Building 4708 West High Bay. Although management of the U.S. elements for the Station were consolidated in 1994, module and node development continued at MSFC by Boeing Company, the prime contractor for the Space Station.

  1. Stage measurement at gaging stations

    USGS Publications Warehouse

    Sauer, Vernon B.; Turnipseed, D. Phil

    2010-01-01

    Stream and reservoir stage are critical parameters in the computation of stream discharge and reservoir volume, respectively. In addition, a record of stream stage is useful in the design of structures that may be affected by stream elevation, as well as for the planning for various uses of flood plains. This report describes equipment and methodology for the observation, sensing, and recording of stage in streams and reservoirs. Although the U.S. Geological Survey (USGS) still uses the traditional, basic stilling-well float system as a predominant gaging station, modern electronic stage sensors and water-level recorders are now commonly used. Bubble gages coupled with nonsubmersible pressure transducers eliminate the need for stilling wells. Submersible pressure transducers have become common in use for the measurement of stage in both rivers and lakes. Furthermore, noncontact methods, such as radar, acoustic, and laser methods of sensing water levels, are being developed and tested, and in the case of radar, are commonly used for the measurement of stage. This report describes commonly used gaging-station structures, as well as the design and operation of gaging stations. Almost all of the equipment and instruments described in this report will meet the accuracy standard set by the USGS Office of Surface Water (OSW) for the measurement of stage for most applications, which is ?0.01 foot (ft) or 0.2 percent of the effective stage. Several telemetry systems are used to transmit stage data from the gaging station to the office, although satellite telemetry has become the standard. These telemetry systems provide near real-time stage data, as well as other information that alerts the hydrographer to extreme or abnormal events, and instrument malfunctions.

  2. Characterization of the bending stiffness of large space structure joints

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey

    1989-01-01

    A technique for estimating the bending stiffness of large space structure joints is developed and demonstrated for an erectable joint concept. Experimental load-deflection data from a three-point bending test was used as input to solve a closed-form expression for the joint bending stiffness which was derived from linear beam theory. Potential error sources in both the experimental and analytical procedures are identified and discussed. The bending stiffness of a mechanically preloaded erectable joint is studied at three applied moments and seven joint orientations. Using this technique, the joint bending stiffness was bounded between 6 and 17 percent of the bending stiffness of the graphite/epoxy strut member.

  3. Space Station Live: Station Communications Upgrade

    NASA Image and Video Library

    NASA Public Affairs Officer Nicole Cloutier-Lemasters recently spoke with Penny Roberts, one of the leads for the International Space Station Avionics and Software group, about the upgrade of the K...

  4. Powder River: data for cross-channel profiles at 22 sites in southeastern Montana from 1975 through 2012

    USGS Publications Warehouse

    Moody, John A.; Meade, Robert H.

    2013-01-01

    Powder River rises in the Bighorn Mountains of Wyoming and flows northward through a semi-arid landscape in Wyoming and Montana to the Yellowstone River. The river drains an area of 34,700 km2 and has an average discharge of about 500 million m3 y-1 or 16 m3 s-1. This view of the river looking northward, and hence downstream, was taken in October 2012 (see study reach map), about 20 km north of the Wyoming-Montana state line, about 4 km downstream from an operating gaging station at Moorhead, Montana (USGS station number 06324500), and about 80 river km upstream from a discontinued gaging station at Broadus, Montana (USGS station number 06324710). The river is emerging from a narrowly-confined reach, and the valley widens northward, bordered by hills of the coal-bearing Fort Union Formation. The river in this photo is at about bed-full flow (12 m3 s-1, Moody and others, 1999), and several riffles with disturbed water can be seen downstream between smooth glassy reaches of the river. A narrow band (~2-4 m wide) of reddish sedge (Scirpus spp.) grows just above the bed-full level along the edge of water with a wider band of mixed grasses (Agropyron repens, A. pauciflorum, Bromus inermis, Elymus canadenis, Spartina pectinata, and S. cynosoroids), willow (Salix exigua), tamarisk (Tamirix ramosissima) and small cottonwood seedlings and trees (Populus sargentii) on the flood plain. Three terrace levels have been identified along the river (Leopold and Miller, 1954; Moody and Meade, 2008). The first is the Lightning terrace with small cottonwood trees (seen here without leaves) adjacent to the floodplain in the right-center of the photo. The second is the Moorcroft terrace seen best forming the left bank and extending as a flat surface to the left (west) with a few large cottonwood trees still retaining their green leaves. The third is the colluvial Kaycee terrace that grades slowly upwards and meets the hills of the Fort Union Formation. It can be seen on the right side

  5. Bending response of single layer MoS2

    NASA Astrophysics Data System (ADS)

    Xiong, Si; Cao, Guoxin

    2016-03-01

    Using molecular mechanics (or dynamics) simulations, three different approaches, including the targeted molecular mechanics, four-point bending and nanotube methods, are employed to investigate the bending response of single layer MoS2 (SLMoS2), among which four-point bending is the most accurate approach to determine the bending stiffness according to the continuum theory. It is found that when the bending curvature radius is large enough (e.g. >4 nm), three approaches will give the same bending stiffness of SLMoS2 and the bending behavior is isotropic for SLMoS2, whereas the nanotube method with small tubes (e.g. <4 nm) cannot give the correct bending stiffness. Compared with the reported result from the MoS2 nanotube calculated by density functional theory, the revised Stillinger-Weber (SW) and reactive empirical bond-order (REBO) potentials can give the reasonable bending stiffness of SLMoS2 (8.7-13.4 eV) as well as the effective deformed conformation. In addition, since the Mo-S bond deformation of SLMoS2 under bending is similar to that under in-plane tension/compression, the continuum bending theory can quite accurately predict the bending stiffness of SLMoS2 if a reasonable thickness of SLMoS2 is given. For SLMoS2, the reasonable thickness should be larger than the distance between its two S atomic planes and lower than the distance between two Mo atomic planes of bulk MoS2 crystal, e.g. 0.375-0.445 nm.

  6. Transient Pinning and Pulling: A Mechanism for Bending Microtubules

    PubMed Central

    Kent, Ian A.; Rane, Parag S.; Dickinson, Richard B.; Ladd, Anthony J. C.; Lele, Tanmay P.

    2016-01-01

    Microtubules have a persistence length of the order of millimeters in vitro, but inside cells they bend over length scales of microns. It has been proposed that polymerization forces bend microtubules in the vicinity of the cell boundary or other obstacles, yet bends develop even when microtubules are polymerizing freely, unaffected by obstacles and cell boundaries. How these bends are formed remains unclear. By tracking the motions of microtubules marked by photobleaching, we found that in LLC-PK1 epithelial cells local bends develop primarily by plus-end directed transport of portions of the microtubule contour towards stationary locations (termed pinning points) along the length of the microtubule. The pinning points were transient in nature, and their eventual release allowed the bends to relax. The directionality of the transport as well as the overall incidence of local bends decreased when dynein was inhibited, while myosin inhibition had no observable effect. This suggests that dynein generates a tangential force that bends microtubules against stationary pinning points. Simulations of microtubule motion and polymerization accounting for filament mechanics and dynein forces predict the development of bends of size and shape similar to those observed in cells. Furthermore, simulations show that dynein-generated bends at a pinning point near the plus end can cause a persistent rotation of the tip consistent with the observation that bend formation near the tip can change the direction of microtubule growth. Collectively, these results suggest a simple physical mechanism for the bending of growing microtubules by dynein forces accumulating at pinning points. PMID:26974838

  7. The mechanics of gravitropic bending in leafy dicot stems

    NASA Technical Reports Server (NTRS)

    Salisbury, F. B.; Mueller, W. J.; Blotter, P. T.; Harris, C. S.; White, R. G.; Gillespie, L. S.; Sliwinski, J. E.

    1982-01-01

    The mechanism of the gravitropic bending in stems of the cocklebur and castor bean are investigated. The results of these experiments demonstrate the quick stopping of growth and the increased tensions on the upper layer of a horizontal stem. It is suggested that bending apparently occurs as the resistance of the upper surface layers is extended to the inner cells below. A model of stem bending is developed which can explain the asymmetry of the stem-cell response.

  8. Compliance measurements of chevron notched four point bend specimen

    NASA Technical Reports Server (NTRS)

    Calomino, Anthony; Bubsey, Raymond; Ghosn, Louis J.

    1994-01-01

    The experimental stress intensity factors for various chevron notched four point bend specimens are presented. The experimental compliance is verified using the analytical solution for a straight through crack four point bend specimen and the boundary integral equation method for one chevron geometry. Excellent agreement is obtained between the experimental and analytical results. In this report, stress intensity factors, loading displacements and crack mouth opening displacements are reported for different crack lengths and different chevron geometries, under four point bend loading condition.

  9. The mechanics of gravitropic bending in leafy dicot stems

    NASA Technical Reports Server (NTRS)

    Salisbury, F. B.; Mueller, W. J.; Blotter, P. T.; Harris, C. S.; White, R. G.; Gillespie, L. S.; Sliwinski, J. E.

    1982-01-01

    The mechanism of the gravitropic bending in stems of the cocklebur and castor bean are investigated. The results of these experiments demonstrate the quick stopping of growth and the increased tensions on the upper layer of a horizontal stem. It is suggested that bending apparently occurs as the resistance of the upper surface layers is extended to the inner cells below. A model of stem bending is developed which can explain the asymmetry of the stem-cell response.

  10. BEND3 mediates transcriptional repression and heterochromatin organization.

    PubMed

    Khan, Abid; Prasanth, Supriya G

    2015-01-01

    Transcription repression plays a central role in gene regulation. Transcription repressors utilize diverse strategies to mediate transcriptional repression. We have recently demonstrated that BEND3 (BANP, E5R and Nac1 domain) protein represses rDNA transcription by stabilizing a NoRC component. We discuss the role of BEND3 as a global regulator of gene expression and propose a model whereby BEND3 associates with chromatin remodeling complexes to modulate gene expression and heterochromatin organization.

  11. BEND3 mediates transcriptional repression and heterochromatin organization

    PubMed Central

    Khan, Abid; Prasanth, Supriya G

    2015-01-01

    Transcription repression plays a central role in gene regulation. Transcription repressors utilize diverse strategies to mediate transcriptional repression. We have recently demonstrated that BEND3 (BANP, E5R and Nac1 domain) protein represses rDNA transcription by stabilizing a NoRC component. We discuss the role of BEND3 as a global regulator of gene expression and propose a model whereby BEND3 associates with chromatin remodeling complexes to modulate gene expression and heterochromatin organization. PMID:26507581

  12. Multiple-cladding fibers with reduced bend loss

    NASA Astrophysics Data System (ADS)

    Tomljenovic-Hanic, Snjezana; Bulla, Douglas A. P.; Ankiewicz, Adrian; Love, John D.; Bailey, Ron

    2007-04-01

    We demonstrate that a highly bend-resistant fiber can be realized. It is shown theoretically that, by introducing both depressed and elevated rings into the cladding, bending loss can be reduced significantly. A fiber based on this design has been fabricated and characterized as a first step toward achieving this goal. The results show that a multiple-cladding fiber is highly bend resistant when compared with the standard telecom single-mode fiber.

  13. Bending response of single layer MoS2.

    PubMed

    Xiong, Si; Cao, Guoxin

    2016-03-11

    Using molecular mechanics (or dynamics) simulations, three different approaches, including the targeted molecular mechanics, four-point bending and nanotube methods, are employed to investigate the bending response of single layer MoS2 (SLMoS2), among which four-point bending is the most accurate approach to determine the bending stiffness according to the continuum theory. It is found that when the bending curvature radius is large enough (e.g. >4 nm), three approaches will give the same bending stiffness of SLMoS2 and the bending behavior is isotropic for SLMoS2, whereas the nanotube method with small tubes (e.g. <4 nm) cannot give the correct bending stiffness. Compared with the reported result from the MoS2 nanotube calculated by density functional theory, the revised Stillinger-Weber (SW) and reactive empirical bond-order (REBO) potentials can give the reasonable bending stiffness of SLMoS2 (8.7-13.4 eV) as well as the effective deformed conformation. In addition, since the Mo-S bond deformation of SLMoS2 under bending is similar to that under in-plane tension/compression, the continuum bending theory can quite accurately predict the bending stiffness of SLMoS2 if a reasonable thickness of SLMoS2 is given. For SLMoS2, the reasonable thickness should be larger than the distance between its two S atomic planes and lower than the distance between two Mo atomic planes of bulk MoS2 crystal, e.g. 0.375-0.445 nm.

  14. Space Station attached payloads

    NASA Technical Reports Server (NTRS)

    Clark, Lenwood G.

    1990-01-01

    The Space Station Freedom is being designed and developed with user requirements being used to shape the configuration. Plans include accommodation provisions for a wide variety of attached payloads including the Earth sciences research activities which are the focus of this conference. The station program is even beginning some preliminary payload manifesting which involves planning for accommodation of payload during the station's assembly flights. Potential payload organizations should be aware of the station's plans for payload accommodations so as to guide their own payload activities for future space station use.

  15. Neuroradiology viewing station

    NASA Astrophysics Data System (ADS)

    Lou, Shyhliang A.; Lufkin, Robert B.; Valentino, Daniel J.; Huang, H. K.; Hanafee, William; Jabour, Bradly; Bentsen, John R.; Duckwiler, Gary R.; Dion, Jacques E.

    1990-07-01

    A distributed CT/MR digital viewing station for the neuroradiology section has been developed and is being evaluated in our department. The major components of the station consist of a SUN host computer, a PIXAR II image processor, and four 1K x 1K progressive video monitors. The software modules operating in the station include an image acquisition process, a local database process, and an user image display and processing process. Functions provided by the station are described. Preliminary results obtained from clinical evaluation are reported. Future plans to refine the station are presented.

  16. Dynamic characteristics of power-tower space stations with 15-foot truss bays

    NASA Technical Reports Server (NTRS)

    Dorsey, J. T.

    1986-01-01

    A power tower space station concept which generates power with photovoltaic arrays and where the truss structure has a bay size of 15 ft is described. Rigid body and flexible body dynamic characteristics are presented for a 75-kW Initial Operating Capability (IOC) and 150-kW and 300-kW growth stations. The transient response of the IOC and 300-kW growth stations to shuttle dock, orbit reboost, and mobile remote manipulator system translation loads are studied. Displacements, accelerations, and bending moments at various locations on the IOC and 300-kW growth stations are presented.

  17. Investigation of Water Quality and Plankton in Selected Aquatic Habitats on the Lower Mississippi river.

    DTIC Science & Technology

    1984-04-01

    At the relatively depauperate main channel stations, Keratella (principally K. cochlearis), followed by Vorticella , copepod nauplii, Brachionus...both of the Matthews Bend stations, but rare at main channel stations. Vorticella , plentiful at main channel stations, was relatively scarce at LEGEND -O...cochlearis. The second most numerous taxon was the stalked protozoan Vorticella . As 5 7 Vorticella normally attaches to substrates (Kudo 1966), their

  18. Amazon River discharge estimated from TOPEX/Poseidon altimetry

    NASA Astrophysics Data System (ADS)

    Zakharova, Elena A.; Kouraev, Alexei V.; Cazenave, Anny; Seyler, Frédérique

    2006-02-01

    This paper presents an application of the TOPEX/Poseidon (T/P) satellite altimetry data to estimate river discharge at three sites along the Amazon River. We discuss the methodology to establish empirical relationships between satellite-derived water levels and daily estimations of river discharges based on rating curves and in situ level measurements at gauging stations. Three sites are chosen: Manacapuru (River Solimões), Jatuarana (nearby the confluence of the Solimões and Rio Negro rivers) and Óbidos (Amazon River). We then reconstruct the satellite-based river discharge over a 10-year time span (1992-2002). Comparison between satellite-derived and river discharge at the gauging stations shows that the T/P data can successfully be used for hydrological studies of large rivers, in providing in particular discharge estimates when in situ data are not available. To cite this article: E.A. Zakharova et al., C. R. Geoscience 338 (2006).

  19. Decline of radionuclides in Columbia River biota

    SciTech Connect

    Cushing, C.E.; Watson, D.G.; Scott, A.J.; Gurtisen, J.M.

    1980-03-01

    In January 1971, the last of nine plutonium production reactors using direct discharge of once-through cooling waters into the Columbia River was closed. Sampling was initiated at three stations on the Columbia River to document the decline of the radionuclide body burdens in the biota of the Columbia River ecosystem. The data show that in a river-reservoir complex, the measurable body burden of fission-produced radionuclides decreased to essentially undetectable levels within 18 to 24 mo after cessation of discharge of once-through cooling water into the river. On the basis of data from the free-flowing station, we believe that this decrease would be even more rapid in an unimpounded river.

  20. High-efficiency beam bending using graded photonic crystals.

    PubMed

    Oner, B B; Turduev, M; Kurt, H

    2013-05-15

    We explore beam-bending properties of graded index (GRIN) waveguide with hyperbolic secant profile. The transmission efficiency and bandwidth features are extracted for GRIN photonic crystal (PC) media composed of dielectric rods. Light guiding performance of the GRIN PC medium is analyzed for 90° and 180° waveguide bends. The finite-difference time-domain method is deployed to investigate the performance of the designed GRIN waveguides. By the help of proposed photonic configuration, bending of light is achieved with a high efficiency within a broad bandwidth, which promotes the use of GRIN PC structures for efficient light-bending purposes.

  1. Electrostatic effects in DNA bending by GCN4 mutants.

    PubMed

    Strauss-Soukup, J K; Maher, L J

    1998-01-27

    DNA architecture has been shown to be important for cellular processes such as activation of transcription, recombination, and replication. Many proteins reconfigure the shape of duplex DNA upon binding. Previous experiments have shown that some members of the eukaryotic bZIP family of DNA binding proteins appear to bend DNA, while others do not. We are exploring the role of electrostatic effects in DNA bending by bZIP proteins. The yeast bZIP transcription factor GCN4 does not induce DNA bending in vitro. Previously we substituted basic residues for three neutral amino acids in GCN4 to produce a GCN4 derivative that bends DNA by approximately 15 degrees. This result is consistent with a model of induced DNA bending wherein excess positive charge in proximity to one face of the double helix neutralizes local phosphate diester anions resulting in a laterally-asymmetric charge distribution along the DNA. Such an unbalanced charge distribution can result in collapse of the DNA toward the neutralized surface. We now present a more comprehensive analysis of electrostatic effects in DNA bending by GCN4 derivatives. It is shown that the direction and extent of DNA bending by these derivatives are a linear function of the charges of the amino acids adjacent to the basic domain of the protein. This relation holds over the charge range +6 (16 degrees bend toward the minor groove) to -6 (25 degrees bend toward the major groove).

  2. Bending-induced extension in two-dimensional crystals

    NASA Astrophysics Data System (ADS)

    Pan, Douxing; Li, Yao; Wang, Tzu-Chiang; Guo, Wanlin

    2017-02-01

    We find by ab initio simulations that significant overall tensile strain can be induced by pure bending in a wide range of two-dimensional crystals perpendicular to the bending moment, just like an accordion being bent to open. This bending-induced tensile strain increases in a power law with bent curvature and can be over 20% in monolayered black phosphorus and transition metal dichalcogenides at a moderate curvature of 2 nm^{-1} but more than an order weaker in graphene and hexagon boron nitride. This accordion effect is found to be a quantum mechanical effect raised by the asymmetric response of chemical bonds and electron density to the bending curvature.

  3. Bending Behavior of Porous Sintered Stainless Steel Fiber Honeycombs

    NASA Astrophysics Data System (ADS)

    Zou, Shuiping; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2017-02-01

    A novel porous honeycomb-type substrate has been developed using solid-state sintering stainless steel fibers. The porous sintered stainless steel fiber honeycombs (PSSSFH) are composed of a skeleton of sintered stainless steel fibers, three-dimensionally interconnected porous structures and multiple parallel microchannels. The bending behavior of the PSSSFH is investigated using three-point bending tests. Four stages, including an elastic stage, a yielding stage with a plateau, a hardening stage and a failure stage, are observed during the bending process of the PSSSFH. In the initial yielding stage, the bending forces increase slowly with displacement increasing, and then a yielding plateau follows, which is unique compared with other porous materials. Moreover, the structure parameters of the PSSSFH are varied to investigate the influence on the bending strength. It is determined that the multiple parallel microchannels can enhance the bending strength of porous stainless steel fiber sintered substrates (PSSFSS) and do not influence the variation trend of bending strength of PSSFSS with porosity increasing. The open ratio is conducive to increasing the bending strength, and the microchannel diameters ranging from 0.5 mm to 1.5 mm have little influence on the bending strength. In addition, both the increasing of sintering temperature and sintering time can strengthen the PSSSFH.

  4. Bending Behavior of Porous Sintered Stainless Steel Fiber Honeycombs

    NASA Astrophysics Data System (ADS)

    Zou, Shuiping; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2016-12-01

    A novel porous honeycomb-type substrate has been developed using solid-state sintering stainless steel fibers. The porous sintered stainless steel fiber honeycombs (PSSSFH) are composed of a skeleton of sintered stainless steel fibers, three-dimensionally interconnected porous structures and multiple parallel microchannels. The bending behavior of the PSSSFH is investigated using three-point bending tests. Four stages, including an elastic stage, a yielding stage with a plateau, a hardening stage and a failure stage, are observed during the bending process of the PSSSFH. In the initial yielding stage, the bending forces increase slowly with displacement increasing, and then a yielding plateau follows, which is unique compared with other porous materials. Moreover, the structure parameters of the PSSSFH are varied to investigate the influence on the bending strength. It is determined that the multiple parallel microchannels can enhance the bending strength of porous stainless steel fiber sintered substrates (PSSFSS) and do not influence the variation trend of bending strength of PSSFSS with porosity increasing. The open ratio is conducive to increasing the bending strength, and the microchannel diameters ranging from 0.5 mm to 1.5 mm have little influence on the bending strength. In addition, both the increasing of sintering temperature and sintering time can strengthen the PSSSFH.

  5. Modified Numerical Simulation Model of Blood Flow in Bend

    PubMed Central

    Liu, X; Zhou, X; Hao, X; Sang, X

    2015-01-01

    ABSTRACT The numerical simulation model of blood flow in bend is studied in this paper. The curvature modification is conducted for the blood flow model in bend to obtain the modified blood flow model in bend. The modified model is verified by U tube. By comparing the simulation results with the experimental results obtained by measuring the flow data in U tube, it was found that the modified blood flow model in bend can effectively improve the prediction accuracy of blood flow data affected by the curvature effect. PMID:27398727

  6. Hot bending with a fiber coupled solid state laser

    NASA Astrophysics Data System (ADS)

    Bammer, F.; Schumi, T.; Schuöcker, D.

    2010-09-01

    For bending of brittle materials it is necessary to heat up the forming zone. This can be done with a fiber coupled solid state laser, whose beam is evenly distributed on the bending line with a beam splitter installed in the lower tool (die) of a bending press. With polarization optics the laser beam is divided there into partial beams that are evenly distributed on the bending line with lenses and prisms. A setup for a bending length of 200mm heated by a fiber-coupled 3kW Nd:YAG-laser shows the feasibility of the concept. Successful operation was shown for the Mg-alloy AZ31, which breaks during forming at room temperature, but can be well formed at temperatures in the range of 200-300°C. Other materials benefiting from this method are Ti-alloys, high-strength-Al-alloys, and high-strength-steels. Typical heating times are in the range of up to 5s and much of the heat input is generated during the bending operation where the laser continues to work. Laser Assisted Bending with a fiber coupled solid state laser is a straightforward way to perform the bending of brittle materials in a process as simple as cold bending.

  7. Sorting of bed load sediment by flow in meander bends.

    USGS Publications Warehouse

    Parker, G.; Andrews, E.D.

    1985-01-01

    Equilibrium sorting of coarse mobile bed load sediment in meander bends is considered. A theory of two-dimensional bed load transport of graded material, including the effects of gravity on lateral slopes and secondary currents, is developed. This theory is coupled with a simple tratement of flow in bends, an analytically determined bend shape, and the condition of continuity of each grain size range in transport to describe sorting. The theory indicates that the locus of coarse sediment shifts from the inside bank to the outside bank near the bend apex, as is observed.-Authors

  8. PERMEABILITY OF SALTSTONE MEASUREMENT BY BEAM BENDING

    SciTech Connect

    Harbour, J; Tommy Edwards, T; Vickie Williams, V

    2008-01-30

    One of the goals of the Saltstone variability study is to identify (and, quantify the impact of) the operational and compositional variables that control or influence the important processing and performance properties of Saltstone mixes. A performance property for Saltstone mixes that is important but not routinely measured is the liquid permeability or saturated hydraulic conductivity of the cured Saltstone mix. The value for the saturated hydraulic conductivity is an input into the Performance Assessment for the SRS Z-Area vaults. Therefore, it is important to have a method available that allows for an accurate and reproducible measurement of permeability quickly and inexpensively. One such method that could potentially meet these requirements for the measurement of saturated hydraulic conductivity is the technique of beam bending, developed by Professor George Scherer at Princeton University. In order to determine the feasibility of this technique for Saltstone mixes, a summer student, David Feliciano, was hired to work at Princeton under the direction of George Scherer. This report details the results of this study which demonstrated the feasibility and applicability of the beam bending method to measurement of permeability of Saltstone samples. This research effort used samples made at Princeton from a Modular Caustic side solvent extraction Unit based simulant (MCU) and premix at a water to premix ratio of 0.60. The saturated hydraulic conductivities for these mixes were measured by the beam bending technique and the values determined were of the order of 1.4 to 3.4 x 10{sup -9} cm/sec. These values of hydraulic conductivity are consistent with independently measured values of this property on similar MCU based mixes by Dixon and Phifer. These values are also consistent with the hydraulic conductivity of a generic Saltstone mix measured by Langton in 1985. The high water to premix ratio used for Saltstone along with the relatively low degree of hydration for

  9. Boundary shear stress along rigid trapezoidal bends

    Treesearch

    Christopher I. Thornton; Kyung-Seop Sin; Paul Sclafani; Steven R. Abt

    2012-01-01

    The migration of alluvial channels through the geologic landform is an outcome of the natural erosive processes. Mankind continually attempts to stabilize channel meandering processes, both vertically and horizontally, to reduce sediment discharge, provide boundary definition, and enable economic development along the river's edge. A critical component in the...

  10. Flooding of the Androscoggin River during December 18-19, 2003, in Canton, Maine

    USGS Publications Warehouse

    Dudley, Robert W.

    2005-01-01

    The Androscoggin River flooded the town of Canton, Maine in December 2003, resulting in damage to and (or) evacuation of 44 homes. Streamflow records at the U.S. Geological Survey (USGS) streamflow-gaging stations at Rumford (USGS station identification number 01054500) and Auburn (01059000) were used to estimate the peak streamflow for the Androscoggin in the town of Canton for this flood (December 18-19, 2003). The estimated peak flood streamflow at Canton was approximately 39,800 ft3/s, corresponding to an estimated recurrence interval of 4.4 years; however, an ice jam downstream from Canton Point on December 18-19 obstructed river flow resulting in a high-water elevation commensurate with an open-water flood approximately equal to a 15-year event. The high water-surface elevations attained during the December 18-19 flood event in Canton were higher than the expected open-water flood water-surface elevations; this verified the assumption that the water-surface elevation was augmented due to the downstream ice jam The change in slope of the riverbed from upstream of Canton to the impoundment at the downstream corporate limits, and the river bend near Stevens Island are principal factors in ice-jam formation near Canton. The U.S. Army Corps of Engineers Ice Jam Database indicates five ice-jam-related floods (including December 2003) for the town of Canton: March 13, 1936; January 1978; March 12, 1987; January 29, 1996; and December 18-19, 2003. There have been more ice-jam-related flood events in Canton than these five documented events, but the exact number and nature of ice jams in Canton cannot be determined without further research.

  11. Bend-insensitive fiber based vibration sensor

    NASA Astrophysics Data System (ADS)

    Xu, Yanping; Lu, Ping; Baset, Farhana; Bhardwaj, Vedula Ravi; Bao, Xiaoyi

    2014-05-01

    We report two novel fiber-optic vibration sensors based on standard telecom bend-insensitive fiber (BIF). A tapered BIF forming a fiber Mach-Zehnder interferometer could measure continuous and damped vibration from 1 Hz up to 500 kHz. An enclosed microcantilever is fabricated inside the BIF by chemical etching and fusion spliced with a readout singlemode fiber that exhibits a frequency range from 5 Hz to 10 kHz with high signal-to-noise ratio (SNR) up to 68 dB. The unique double cladding structure of the BIF ensures both sensors with advantages of compactness, high resistance to the external disturbance and stronger mechanical strength.

  12. Bending equation for a quasianisotropic plate

    NASA Astrophysics Data System (ADS)

    Shachnev, V. A.

    2010-10-01

    In the framework of the linear theory of elasticity, an exact bending equation is obtained for the median plane of a plate whose material is a monoclinic system with the axis of symmetry perpendicular to the plate plane. As an example, the equation of the median plane of an isotropic plate is considered; the operator of this equation coincides with the operator of Sophie Germain's approximate equation. As the plate thickness tends to zero, the right-hand side of the equation is asymptotically equivalent to the right-hand side of the approximate equation. In addition, equations relating the median plane transverse stresses and the total stresses in the plate boundary planes to the median plane deflexions are obtained.

  13. Separation of blood in microchannel bends

    NASA Astrophysics Data System (ADS)

    Blattert, Christoph; Jurischka, Reinhold; Schoth, Andreas; Kerth, Paul; Menz, Wolfgang

    2004-01-01

    Biological applications of micro assay devices require integrated on-chip microfluidics for separation of plasma or serum from blood. This is achieved by a new blood separation technique based on a microchannel bend structure developed within the collaborative Micro-Tele-BioChip (μTBC) project co-funded by the German Ministry For Education and Research (BMBF). Different prototype polymer chips have been manufactured with an UV-LIGA process and hot embossing technology. The separation efficiency of these chips has been determined by experimental measurements using human whole blood. Results show different separation efficiencies for cells and plasma depending on microchannel geometry and blood sample characteristics and suggest an alternative blood separation method as compared to existing micro separation technologies.

  14. Separation of blood in microchannel bends

    NASA Astrophysics Data System (ADS)

    Blattert, Christoph; Jurischka, Reinhold; Schoth, Andreas; Kerth, Paul; Menz, Wolfgang

    2003-12-01

    Biological applications of micro assay devices require integrated on-chip microfluidics for separation of plasma or serum from blood. This is achieved by a new blood separation technique based on a microchannel bend structure developed within the collaborative Micro-Tele-BioChip (μTBC) project co-funded by the German Ministry For Education and Research (BMBF). Different prototype polymer chips have been manufactured with an UV-LIGA process and hot embossing technology. The separation efficiency of these chips has been determined by experimental measurements using human whole blood. Results show different separation efficiencies for cells and plasma depending on microchannel geometry and blood sample characteristics and suggest an alternative blood separation method as compared to existing micro separation technologies.

  15. Floating objects with finite resistance to bending.

    PubMed

    Vella, Dominic

    2008-08-19

    We consider the equilibrium flotation of a thin, flexible cylinder at the interface between a liquid and a gas. In particular, we determine the maximum load that such a cylinder can support without sinking. We find that as the length of such a cylinder increases the maximum load at first increases. However, the maximum load reaches a plateau when the length of the cylinder is comparable to the elastocapillary length, which is determined by a balance between the bending of the cylinder and surface tension. We then consider the implications of our analysis for the walking on water of both arthropods and man-made robots. In particular, we show that the legs of water striders are typically slightly shorter than this 'optimal' length, suggesting that elastocapillary effects may act as a selection pressure.

  16. Bending of Light in Ellis Wormhole Geometry

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Amrita; Potapov, Alexander A.

    A recent work by Dey and Sen derived the approximate light deflection angle α by an Ellis wormhole in terms of proper radial distance ℓ that covers the entire spacetime. On the other hand, Bodenner and Will calculated the expressions for light bending in Schwarzschild geometry using various coordinates and showed that they all reduce to a single formula when re-expressed in the coordinate independent language of "circumferential radius" rC identified with the standard radial coordinate rS. We shall argue that the coordinate invariant language for two-way wormholes should be ℓ rather than rS. Hence here we find the exact deflection α in Ellis wormhole geometry first in terms of ℓ and then in terms of rS. We confirm the latter expression using three different methods. We argue that the practical measurement scheme does not necessarily single out either ℓ or rS. Some errors in the literature are corrected.

  17. Light bending in f(T) gravity

    NASA Astrophysics Data System (ADS)

    Ruggiero, Matteo Luca

    2016-05-01

    In the framework of f(T) gravity, we focus on a weak-field and spherically symmetric solution for the Lagrangian f(T) = T + αT2, where α is a small constant which parametrizes the departure from general relativity (GR). In particular, we study the propagation of light and obtain the correction to the general relativistic bending angle. Moreover, we discuss the impact of this correction on some gravitational lensing observables, and evaluate the possibility of constraining the theory parameter α by means of observations. In particular, on taking into account the astrometric accuracy in the Solar System, we obtain that |α|≤ 1.85 × 105m2; this bound is looser than those deriving from the analysis of Solar System dynamics, e.g. |α|≤ 5 × 10-1m2 [L. Iorio, N. Radicella and M. L. Ruggiero, J. Cosmol. Astropart. Phys. 1508 (2015) 021, arXiv:1505.06996 [gr-qc].], |α|≤ 1.8 × 104m2 [L. Iorio and E. N. Saridakis, Mon. Not. R. Astron. Soc. 427 (2012) 1555, arXiv:1203.5781 [gr-qc].] or |α|≤ 1.2 × 102m2 [Y. Xie and X. M. Deng, Mon. Not. R. Astron. Soc. 433 (2013) 3584, arXiv:1312.4103 [gr-qc].]. However, we suggest that, since the effect only depends on the impact parameter, better constraints could be obtained by studying light bending from planetary objects.

  18. 33 CFR 117.511 - West Pearl River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false West Pearl River. 117.511 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.511 West Pearl River. (a) The draw of the Norfolk Southern railroad bridge, mile 22.1 at Pearl River Station, shall open on signal if at...

  19. 33 CFR 117.511 - West Pearl River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false West Pearl River. 117.511 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.511 West Pearl River. (a) The draw of the Norfolk Southern railroad bridge, mile 22.1 at Pearl River Station, shall open on signal if at...

  20. 33 CFR 117.511 - West Pearl River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false West Pearl River. 117.511 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.511 West Pearl River. (a) The draw of the Norfolk Southern railroad bridge, mile 22.1 at Pearl River Station, shall open on signal if at...

  1. A pulsatile developing flow in a bend

    NASA Astrophysics Data System (ADS)

    Thiriet, M.; Graham, J. M. R.; Issa, R. I.

    1992-06-01

    Low frequency pulsatile flow of an incompressible viscous fluid has been numerically investigated in a rigid 90° bend of circular cross-section, using the finite-volume method. The governing parameters are as follows : amplitude ratio of 1.25, Womersley parameter of 4, peak Reynolds number of 358, peak Dean number of 113, Strouhal number ranging from 0.05 to 0.45. With this set of input data, no flow reversal is observed and a single axial vortex occurs in the half cross-section. Upstream and downstream effects of the bend are mainly characterized by an inward shift of the peak axial velocity in the upstream straight tube and the persistency of the secondary motions several diameters down the exit straight pipe. Secondary motions, present in steady flow, weaken greatly when the unsteady axial component of the flow (W) is lower than the mean flow bar{W}. The axial shear stress tau_a, whose maximum is more often located at the outer part of the bend, increases and remains nearly constant about 8 diameters downstream from the bend inlet. The circumferential shear stress tau_c maximum, located slightly towards the outer bend, is 28% of tau_a maximum, and 20% when W < bar{W}. The magnitude of both tau_a and tau_c increases during the accelerative phase. The low shear region is more often located near the inner tube wall. However, the existence of bends in a tube network might increase the deposit of solid particles, with respect to straight pipes, only when W (t)>W, and locally at the inner edge. Un écoulement pulsé à basse fréquence d'un fluide incompressible visqueux a été étudié numériquement dans un coude, à 90°, de parois rigides et de section droite circulaire et constante, par la méthode des volumes finis. Les valeurs des paramètres adimensionnels gouvernant l'écoulement sont: un rapport d'amplitude de 1,25, un paramètre de Womersley de 4, un nombre de Reynolds crête de 358, un nombre de Dean crête de 113; le nombre de Strouhal varie entre 0

  2. Statistical mechanics of bend flexoelectricity and the twist-bend phase in bent-core liquid crystals.

    PubMed

    Shamid, Shaikh M; Dhakal, Subas; Selinger, Jonathan V

    2013-05-01

    We develop a Landau theory for bend flexoelectricity in liquid crystals of bent-core molecules. In the nematic phase of the model, the bend flexoelectric coefficient increases as we reduce the temperature toward the nematic to polar phase transition. At this critical point, there is a second-order transition from high-temperature uniform nematic phase to low-temperature nonuniform polar phase composed of twist-bend or splay-bend deformations. To test the predictions of Landau theory, we perform Monte Carlo simulations to find the director and polarization configurations as functions of temperature, applied electric field, and interaction parameters.

  3. [Impacts of large hydropower station on benthic algal communities].

    PubMed

    Jia, Xing-Huan; Jiang, Wan-Xiang; Li, Feng-Qing; Tang, Tao; Duan, Shu-Gui; Cai, Qing-Hua

    2009-07-01

    To investigate the impacts of large hydropower station in Gufu River on benthic algae, monthly samplings were conducted from September 2004 to June 2007 at the site GF04 which was impacted by the hydropower station, with the site GL03 in Gaolan River as reference. During sampling period, no significant differences were observed in the main physicochemical variables between GF04 and GL03, but the hydrodynamics differed significantly. GL03 was basically at a status of slow flow; while GF04, owing to the discharging from the reservoir, was at a riffle status during more than 60% of the sampling period. Such a difference in hydrodynamics induced significant differences in the community similarity of benthic algae and the relative abundance of unattached diatoms, erect diatoms, and stalked diatoms between GF04 and GL03, which could better reflect the impacts of irregular draw-off by large hydropower station on river eco-system.

  4. Index of stations: surface-water data-collection network of Texas, September 1999

    USGS Publications Warehouse

    Gandara, Susan C.; Barbie, Dana L.

    2001-01-01

    As of September 30, 1999, the surface-water data-collection network of Texas (table 1) included 321 continuous-record streamflow stations (D), 20 continuous-record gage-height only stations (G), 24 crest-stage partial-record stations (C), 40 floodhydrograph partial-record stations (H), 25 low-flow partial-record stations (L), 1 continuous-record temperature station (M1), 25 continuous-record temperature and specific conductance stations (M2), 17 continuous-record temperature, specific conductance, dissolved oxygen, and pH stations (M4), 4 daily water-quality stations (Qd), 115 periodic water-quality stations (Qp), 17 reservoir/lake surveys for water quality stations (Qs), 85 continuous or daily reservoircontent stations (R), and 10 daily precipitation stations (Pd). Plate 1 identifies the major river basins in Texas and shows the location of the stations listed in table 1. Table 1 shows the station number and name, latitude and longitude, type of station, and office responsible for the collection of the data and maintenance of the record. An 8-digit permanent numerical designation for all gaging stations has been adopted on a nationwide basis; stations are numbered and listed in downstream order. In the downstream direction along the main stem, all stations on a tributary entering between two main-stem stations are listed between these two stations. A similar order is followed in listing stations by first rank, second rank, and other ranks of tributaries. The rank of any tributary, with respect to the stream to which it is an immediate tributary, is indicated by an indention in the table. Each indention represents one rank. This downstream order and system of indention shows which gaging stations are on tributaries between any two stations on a main stem and the rank of the tributary on which each gaging station is situated.

  5. Automating existing stations

    SciTech Connect

    Little, J.E.

    1986-09-01

    The task was to automate 20 major compressor stations along ANR Pipeline Co.'s Southeastern and Southwestern pipelines in as many months. Meeting this schedule required standardized hardware and software design. Working with Bristol Babcock Co., ANR came up with an off-the-shelf station automation package suitable for a variety of compressor stations. The project involved 148 engines with 488,880-hp in the 20 stations. ANR Pipeline developed software for these engines and compressors, including horsepower prediction and efficiency. The system places processors ''intelligence'' at each station and engine to monitor and control operations. The station processor receives commands from the company's gas dispatch center at Detroit and informs dispatchers of alarms, conditions, and decision it makes. The automation system is controlled by the Detroit center through a central communications network. Operating orders from the center are sent to the station processor, which obeys orders using the most efficient means of operation at the station's disposal. In a malfunction, a control and communications backup system takes over. Commands and information are directly transmitted between the center and the individual compressor stations. Stations receive their orders based on throughput, with suction and discharge pressure overrides. Additionally, a discharge temperature override protects pipeline coatings.

  6. Coupled-Mode Flutter of Bending-Bending Type in Highly-Flexible Uniform Airfoils

    NASA Astrophysics Data System (ADS)

    Pourazarm, Pariya; Modarres-Sadeghi, Yahya

    2016-11-01

    We study the behavior of a highly flexible uniform airfoil placed in wind both numerically and experimentally. It is shown that for a non-rotating highly-flexible cantilevered airfoil, placed at very small angles of attack (less than 1 degree), the airfoil loses its stability by buckling. For slightly higher angles of attack (more than 1 degree) a coupled-mode flutter in which the first and the second flapwise modes coalesce toward a flutter mode is observed, and thus the observed flutter has a bending-bending nature. The flutter onset and frequency found experimentally matched the numerical predictions. If the same airfoil is forced to rotate about its fixed end, the static deflection decreases and the observed couple-mode flutter becomes of flapwise-torsional type, same as what has already been observed for flutter of rotating wind turbine blades. The support provided by the National Science Foundation, CBET-1437988, is greatly acknowledged.

  7. Bending the Curve: Sensitivity to Bending of Curved Paths and Application in Room-Scale VR.

    PubMed

    Langbehn, Eike; Lubos, Paul; Bruder, Gerd; Steinicke, Frank

    2017-04-01

    Redirected walking (RDW) promises to allow near-natural walking in an infinitely large virtual environment (VE) by subtle manipulations of the virtual camera. Previous experiments analyzed the human sensitivity to RDW manipulations by focusing on the worst-case scenario, in which users walk perfectly straight ahead in the VE, whereas they are redirected on a circular path in the real world. The results showed that a physical radius of at least 22 meters is required for undetectable RDW. However, users do not always walk exactly straight in a VE. So far, it has not been investigated how much a physical path can be bent in situations in which users walk a virtual curved path instead of a straight one. Such curved walking paths can be often observed, for example, when users walk on virtual trails, through bent corridors, or when circling around obstacles. In such situations the question is not, whether or not the physical path can be bent, but how much the bending of the physical path may vary from the bending of the virtual path. In this article, we analyze this question and present redirection by means of bending gains that describe the discrepancy between the bending of curved paths in the real and virtual environment. Furthermore, we report the psychophysical experiments in which we analyzed the human sensitivity to these gains. The results reveal encouragingly wider detection thresholds than for straightforward walking. Based on our findings, we discuss the potential of curved walking and present a first approach to leverage bent paths in a way that can provide undetectable RDW manipulations even in room-scale VR.

  8. Space station, 1959 to . .

    NASA Astrophysics Data System (ADS)

    Butler, G. V.

    1981-04-01

    Early space station designs are considered, taking into account Herman Oberth's first space station, the London Daily Mail Study, the first major space station design developed during the moon mission, and the Manned Orbiting Laboratory Program of DOD. Attention is given to Skylab, new space station studies, the Shuttle and Spacelab, communication satellites, solar power satellites, a 30 meter diameter radiometer for geological measurements and agricultural assessments, the mining of the moons, and questions of international cooperation. It is thought to be very probable that there will be very large space stations at some time in the future. However, for the more immediate future a step-by-step development that will start with Spacelab stations of 3-4 men is envisaged.

  9. Space Station Freedom Utilization Conference

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The topics addressed in Space Station Freedom Utilization Conference are: (1) space station freedom overview and research capabilities; (2) space station freedom research plans and opportunities; (3) life sciences research on space station freedom; (4) technology research on space station freedom; (5) microgravity research and biotechnology on space station freedom; and (6) closing plenary.

  10. Torsion and bending of prismatic rods of hollow rectangular section

    NASA Technical Reports Server (NTRS)

    Abramyan, B L

    1951-01-01

    The torsion and bending of hollow rectangular beams was investigated without the requirement that wall thickness be small compared with the transverse dimensions. The limits of applicability of the usual Bredt formula are indicated for the case of a square hollow tube in torsion. Formulas are given for bending stresses at different parts of the cross section of a hollow rectangular beam.

  11. Observation and Modeling of Single Wall Carbon Nanotube Bend Junctions

    NASA Technical Reports Server (NTRS)

    Han, Jie; Anantram, M. P.; Jaffe, R. L.; Kong, J.; Dai, H.; Saini, Subhash (Technical Monitor)

    1998-01-01

    Single wall carbon nanotube (SWNT) bends, with diameters from approx. 1.0 to 2.5 nm and bend angles from 18 deg. to 34 deg., are observed in catalytic decomposition of hydrocarbons at 600 - 1200 C. An algorithm using molecular dynamics simulation (MD) techniques is developed to model these structures that are considered to be SWNT junctions formed by topological defects (i.e. pentagon-heptagon pairs). The algorithm is used to predict the tube helicities and defect configurations for bend junctions using the observed tube diameters and bend angles. The number and arrangement of the defects at the junction interfaces are found to depend on the tube helicities and bend angle. The structural and energetic calculations using the Brenner potential show a number of stable junction configurations for each bend angle with the 34 deg. bends being more stable than the others. Tight binding calculations for local density of state (LDOS) and transmission coefficients are carried out to investigate electrical properties of the bend junctions.

  12. 36 CFR 7.41 - Big Bend National Park.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Big Bend National Park. 7.41 Section 7.41 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.41 Big Bend National Park. (a) Fishing; closed waters...

  13. 36 CFR 7.41 - Big Bend National Park.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Big Bend National Park. 7.41 Section 7.41 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.41 Big Bend National Park. (a) Fishing; closed waters...

  14. 36 CFR 7.41 - Big Bend National Park.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Big Bend National Park. 7.41 Section 7.41 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.41 Big Bend National Park. (a) Fishing; closed waters...

  15. 36 CFR 7.41 - Big Bend National Park.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Big Bend National Park. 7.41 Section 7.41 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.41 Big Bend National Park. (a) Fishing; closed waters...

  16. 36 CFR 7.41 - Big Bend National Park.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Big Bend National Park. 7.41 Section 7.41 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.41 Big Bend National Park. (a) Fishing; closed waters...

  17. View north of tube bending shop in boilermakers department located ...

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

    View north of tube bending shop in boilermakers department located in southeast corner of the structural shop building (building 57). The computer controlled tube bender can be programmed to bend boiler tubing to nearly any required configuration - Naval Base Philadelphia-Philadelphia Naval Shipyard, Structure Shop, League Island, Philadelphia, Philadelphia County, PA

  18. Flexible DNA bending in HU-DNA cocrystal structures.

    PubMed

    Swinger, Kerren K; Lemberg, Kathryn M; Zhang, Ying; Rice, Phoebe A

    2003-07-15

    HU and IHF are members of a family of prokaryotic proteins that interact with the DNA minor groove in a sequence-specific (IHF) or non-specific (HU) manner to induce and/or stabilize DNA bending. HU plays architectural roles in replication initiation, transcription regulation and site-specific recombination, and is associated with bacterial nucleoids. Cocrystal structures of Anabaena HU bound to DNA (1P71, 1P78, 1P51) reveal that while underlying proline intercalation and asymmetric charge neutralization mechanisms of DNA bending are similar for IHF and HU, HU stabilizes different DNA bend angles ( approximately 105-140 degrees ). The two bend angles within a single HU complex are not coplanar, and the resulting dihedral angle is consistent with negative supercoiling. Comparison of HU-DNA and IHF-DNA structures suggests that sharper bending is correlated with longer DNA binding sites and smaller dihedral angles. An HU-induced bend may be better modeled as a hinge, not a rigid bend. The ability to induce or stabilize varying bend angles is consistent with HU's role as an architectural cofactor in many different systems that may require differing geometries.

  19. BENDING SHOP & OVEN. United Engineering Co., Alameda, California. Plan, ...

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

    BENDING SHOP & OVEN. United Engineering Co., Alameda, California. Plan, two elevations, sections, and details. Alben Froberg, Architect, Oakland, California. Sheet no. 1 of 1. Various scales. December 15, 1941. pencil on tracing paper - United Engineering Company Shipyard, Bending Shop & Oven, 2900 Main Street, Alameda, Alameda County, CA

  20. Studies reveal effects of pipe bends on fluid flow cavitation

    NASA Technical Reports Server (NTRS)

    Stonemetz, R. E.

    1966-01-01

    Incipient cavitation in liquids flowing in pipes curved in one plane are affected by the pipe bend radii and pipe diameters, but little by pipe bend angles ranging from 60 to 120 degrees. Critical cavitation indices decrease with higher Reynolds number and pressure ratio. Bulk liquid temperature increase lowers the mean critical velocity at which cavitation occurs.