Sample records for sloop channel bridge

  1. Delineation of tidal scour through marine geophysical techniques at Sloop Channel and Goose Creek bridges, Jones Beach State Park, Long Island, New York

    USGS Publications Warehouse

    Stumm, Frederick; Chu, Anthony; Reynolds, Richard J.

    2001-01-01

    Inspection of the Goose Creek Bridge in southeastern Nassau County in April 1998 by the New York State Department of Transportation (NYSDOT) indicated a separation of bridge piers from the road bed as a result of pier instability due to apparent seabed scouring by tidal currents. This prompted a cooperative study by the U.S. Geological Survey with the NYSDOT to delineate the extent of tidal scour at this bridge and at the Sloop Channel Bridge, about 0.5 mile to the south, through several marine- geophysical techniques. These techniques included use of a narrow-beam, 200-kilohertz, research-grade fathometer, a global positioning system accurate to within 3 feet, a 3.5 to 7-kilohertz seismic-reflection profiler, and an acoustic Doppler current profiler (ADCP). The ADCP was used only at the Sloop Channel Bridge; the other techniques were used at both bridges.Results indicate extensive tidal scour at both bridges. The fathometer data indicate two major scour holes nearly parallel to the Sloop Channel Bridge—one along the east side, and one along the west side (bridge is oriented north-south). The scour-hole depths are as much as 47 feet below sea level and average more than 40 feet below sea level; these scour holes also appear to have begun to connect beneath the bridge. The deepest scour is at the north end of the bridge beneath the westernmost piers. The east-west symmetry of scour at Sloop Channel Bridge suggests that flood and ebb tides produce extensive scour.The thickness of sediment that has settled within scour holes could not be interpreted from fathometer data alone because fathometer frequencies cannot penetrate beneath the sea-floor surface. The lower frequencies used in seismic-reflection profiling can penetrate the sea floor and underlying sediments, and indicate the amount of infilling of scour holes, the extent of riprap under the bridge, and the assemblages of clay, sand, and silt beneath the sea floor. The seismic- reflection surveys detected 2 to 5 feet of sediment filling the scour holes at both bridges; this indicates that the fathometer surveys were undermeasuring the effective depth of bridge scour by 2 to 5 feet through their inability to penetrate the infilled sediment. Several clay layers with thicknesses of 3 to 5 feet were detected beneath the sea floor at both bridges. Most of the piers beneath Sloop Channel Bridge appear to be surrounded by riprap, but, in several areas the riprap appears to be slumping or sliding into adjacent scour holes. Similar slumping was indicated at the Goose Creek Bridge. Most of the sediment underlying the sea floor at both bridges is interpreted as a fine-grained, cross-bedded sand.ADCP data from Sloop Channel indicate that the constricted flow beneath the bridge increases the horizontal current velocities from 2 to 6 feet per second. Total measured discharge beneath Sloop Channel Bridge was 41,800 cubic feet per second at flood tide and 27,600 cubic feet per second at ebb tide.

  2. World-systems analysis.

    NASA Astrophysics Data System (ADS)

    Evans, Amanda M.

    2007-12-01

    Jamaica sloops were vernacular watercraft designed, built, and utilized by Caribbean colonists beginning in the late-17th century. Despite their popularity, no design or construction records or even a specific definition of their form survive, and many sources simply describe them as an early version of the Bermuda sloop. Vernacular Jamaica sloops were a unique adaptation by English colonists to combat the effects of piracy, and their design was specific to the economic, geographic, and political circumstances of colonial Jamaica. This article proposes a set of characteristics that can be used to define vernacular Jamaica sloops, firstly to distinguish them from the eighteenth-century naval Jamaica-class sloops but also to better understand them as a social response to external stimuli within the complex relationship between maritime economy, piracy and colonial control executed through the navy.

  3. 78 FR 14188 - Safety Zone, Change to Enforcement Period, Patapsco River, Northwest and Inner Harbors; Baltimore...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    ... enforcement period of a safety zone regulation for the annual movement of the historic sloop-of-war USS... sloop-of-war USS CONSTELLATION in Baltimore, Maryland on the Thursday before Memorial Day (observed... McHenry National Monument and Historic Site. Beginning at 3 p.m., the historic Sloop-of-War USS...

  4. 78 FR 1795 - Safety Zone, Change to Enforcement Period, Patapsco River, Northwest and Inner Harbors; Baltimore...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-09

    ... historic sloop-of-war USS CONSTELLATION. This regulation applies to a recurring event that takes place in... Ships in Baltimore is planning to conduct its turn-around ceremony involving the sloop-of-war USS... Monument and Historic Site. Beginning at 3 p.m., the historic Sloop-of-War USS CONSTELLATION will be towed...

  5. Relativistic effects of spacecraft with circumnavigating observer

    NASA Astrophysics Data System (ADS)

    Shanklin, Nathaniel; West, Joseph

    A variation of the recently introduced Trolley Paradox, itself is a variation of the Ehrenfest Paradox is presented. In the Trolley Paradox, a ``stationary'' set of observers tracking a wheel rolling with a constant velocity find that the wheel travels further than its rest length circumference during one revolution of the wheel, despite the fact that the Lorentz contracted circumference is less than its rest value. In the variation presented, a rectangular spacecraft with onboard observers moves with constant velocity and is circumnavigated by several small ``sloops'' forming teams of inertial observers. This whole precession moves relative to a set of ``stationary'' Earth observers. Two cases are presented, one in which the sloops are evenly spaced according to the spacecraft observers, and one in which the sloops are evenly spaced according to the Earth observes. These two cases, combined with the rectangular geometry and an emphasis on what is seen by, and what is measured by, each set of observers is very helpful in sorting out the apparent contradictions. To aid in the visualizations stationary representations in excel along with animation in Visual Python and Unity are presented. The analysis presented is suitable for undergraduate physics majors.

  6. The Sustainability Cycle and Loop: models for a more unified understanding of sustainability.

    PubMed

    Hay, Laura; Duffy, Alex; Whitfield, R I

    2014-01-15

    In spite of the considerable research on sustainability, reports suggest that we are barely any closer to a more sustainable society. As such, there is an urgent need to improve the effectiveness of human efforts towards sustainability. A clearer and more unified understanding of sustainability among different people and sectors could help to facilitate this. This paper presents the results of an inductive literature investigation, aiming to develop models to explain the nature of sustainability in the Earth system, and how humans can effectively strive for it. The major contributions are two general and complementary models, that may be applied in any context to provide a common basis for understanding sustainability: the Sustainability Cycle (S-Cycle), and the Sustainability Loop (S-Loop). Literature spanning multiple sectors is examined from the perspective of three concepts, emerging as significant in relation to our aim. Systems are shown to provide the context for human action towards sustainability, and the nature of the Earth system and its sub-systems is explored. Activities are outlined as a fundamental target that humans need to sustain, since they produce the entities both needed and desired by society. The basic behaviour of activities operating in the Earth system is outlined. Finally, knowledge is positioned as the driver of human action towards sustainability, and the key components of knowledge involved are examined. The S-Cycle and S-Loop models are developed via a process of induction from the reviewed literature. The S-Cycle describes the operation of activities in a system from the perspective of sustainability. The sustainability of activities in a system depends upon the availability of resources, and the availability of resources depends upon the rate that activities consume and produce them. Humans may intervene in these dynamics via an iterative process of interpretation and action, described in the S-Loop model. The models are briefly applied to a system described in the literature. It is shown that the S-Loop may be used to guide efforts towards sustainability in a particular system of interest, by prescribing the basic activities involved. The S-Cycle may be applied complementary to the S-Loop, to support the interpretation of activity behaviour described in the latter. Given their general nature, the models provide the basis for a more unified understanding of sustainability. It is hoped that their use may go some way towards improving the effectiveness of human action towards sustainability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  8. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  9. Multiple Channel Bridges for Spinal Cord Injury: Cellular Characterization of Host Response

    PubMed Central

    Yang, Yang; Laporte, Laura De; Zelivyanskaya, Marina L.; Whittlesey, Kevin J.; Anderson, Aileen J.; Cummings, Brian J.

    2009-01-01

    Bridges for treatment of the injured spinal cord must stabilize the injury site to prevent secondary damage and create a permissive environment that promotes regeneration. The host response to the bridge is central to creating a permissive environment, as the cell types that respond to the injury have the potential to secrete both stimulatory and inhibitory factors. We investigated multiple channel bridges for spinal cord regeneration and correlated the bridge structure to cell infiltration and axonal elongation. Poly(lactide-co-glycolide) bridges were fabricated by a gas foaming/particulate leaching process. Channels within the bridge had diameters of 150 or 250 μm, and the main body of the bridge was highly porous with a controllable pore size. Upon implantation in a rat spinal cord hemisection site, cells infiltrated into the bridge pores and channels, with the pore size influencing the rate of infiltration. The pores had significant cell infiltration, including fibroblasts, macrophages, S-100β-positive cells, and endothelial cells. The channels of the bridge were completely infiltrated with cells, which had aligned axially, and consisted primarily of fibroblasts, S-100β-positive cells, and endothelial cells. Reactive astrocytes were observed primarily outside of the bridge, and staining for chondroitin sulfate proteoglycans was decreased in the region surrounding the bridge relative to studies without bridges. Neurofilament staining revealed a preferential growth of the neural fibers within the bridge channels relative to the pores. Multiple channel bridges capable of supporting cellular infiltration, creating a permissive environment, and directing the growth of neural fibers have potential for promoting and directing spinal cord regeneration. PMID:19382871

  10. Relation of channel stability to scour at highway bridges over waterways in Maryland

    USGS Publications Warehouse

    Doheny, Edward J.; ,

    1993-01-01

    Data from assessments of channel stability and observed-scour conditions at 876 highway bridges over Maryland waterways were entered into a database. Relations were found to exist among specific, deterministic variables and observed-scour and debris conditions. Relations were investigated between (1) high-flow angle of attack and pier- and abutment-footing exposure, (2)abutment location and abutment-footing exposure, (3) type of bed material and pier-footing exposure, (4) tree cover on channel banks and mass wasting of the channel banks, and (5) land use near the bridge and the presence of debris blockage at the bridge opening. The results of the investigation indicate the following: (1) The number of pier and abutment-footing exposures increased for increasing high-flow angles of attack, (2) the number of abutment-footing exposures increased for abutments that protrude into the channel, (3) pier-footing exposures were most common for bridges over streams with channel beds of gravel, (4) mass wasting of channel banks with tree cover of 50 percent or greater near the bridge was less than mass wasting of channel banks with tree cover of less than 50 percent near the bridge, and (5) bridges blockage than bridge in row crop and swamp basins.

  11. Application of the multi-dimensional surface water modeling system at Bridge 339, Copper River Highway, Alaska

    USGS Publications Warehouse

    Brabets, Timothy P.; Conaway, Jeffrey S.

    2009-01-01

    The Copper River Basin, the sixth largest watershed in Alaska, drains an area of 24,200 square miles. This large, glacier-fed river flows across a wide alluvial fan before it enters the Gulf of Alaska. Bridges along the Copper River Highway, which traverses the alluvial fan, have been impacted by channel migration. Due to a major channel change in 2001, Bridge 339 at Mile 36 of the highway has undergone excessive scour, resulting in damage to its abutments and approaches. During the snow- and ice-melt runoff season, which typically extends from mid-May to September, the design discharge for the bridge often is exceeded. The approach channel shifts continuously, and during our study it has shifted back and forth from the left bank to a course along the right bank nearly parallel to the road.Maintenance at Bridge 339 has been costly and will continue to be so if no action is taken. Possible solutions to the scour and erosion problem include (1) constructing a guide bank to redirect flow, (2) dredging approximately 1,000 feet of channel above the bridge to align flow perpendicular to the bridge, and (3) extending the bridge. The USGS Multi-Dimensional Surface Water Modeling System (MD_SWMS) was used to assess these possible solutions. The major limitation of modeling these scenarios was the inability to predict ongoing channel migration. We used a hybrid dataset of surveyed and synthetic bathymetry in the approach channel, which provided the best approximation of this dynamic system. Under existing conditions and at the highest measured discharge and stage of 32,500 ft3/s and 51.08 ft, respectively, the velocities and shear stresses simulated by MD_SWMS indicate scour and erosion will continue. Construction of a 250-foot-long guide bank would not improve conditions because it is not long enough. Dredging a channel upstream of Bridge 339 would help align the flow perpendicular to Bridge 339, but because of the mobility of the channel bed, the dredged channel would likely fill in during high flows. Extending Bridge 339 would accommodate higher discharges and re-align flow to the bridge.

  12. 77 FR 11434 - Safety Zone; Patapsco River, Northwest and Inner Harbors, Baltimore, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ... and Historic Shrine in Baltimore, Maryland, and its return. This action will restrict vessel traffic... Historic Shrine, Baltimore, Maryland. After being turned-around, the USS CONSTELLATION will be returned to... of the historic sloop-of-war USS CONSTELLATION on May 25, 2012. This action is necessary to provide...

  13. Stories of Transformation: Place-Based Education and the Developing Place-Consciousness of Educators along the Hudson River

    ERIC Educational Resources Information Center

    Rosenthal, Jennifer K.

    2011-01-01

    This phenomenological case study investigates the lived experiences of five educators who engage in on-board educational programs, offered by the non-profit environmental organization "Hudson River Sloop Clearwater, Inc", and follows their stories of place-conscious development leading to place-based educational engagement. By analyzing…

  14. Hudson River School

    ERIC Educational Resources Information Center

    McCloskey, Patrick J.

    2004-01-01

    In this article, the author features the "Clearwater," a full-size working replica of a 19th century Hudson River cargo sloop. The "Clearwater" has been serving New York state students as a link to both local history and the environment, helping them to learn lessons about the history of the Hudson River and the environment,…

  15. Generalized ensemble method applied to study systems with strong first order transitions

    DOE PAGES

    Malolepsza, E.; Kim, J.; Keyes, T.

    2015-09-28

    At strong first-order phase transitions, the entropy versus energy or, at constant pressure, enthalpy, exhibits convex behavior, and the statistical temperature curve correspondingly exhibits an S-loop or back-bending. In the canonical and isothermal-isobaric ensembles, with temperature as the control variable, the probability density functions become bimodal with peaks localized outside of the S-loop region. Inside, states are unstable, and as a result simulation of equilibrium phase coexistence becomes impossible. To overcome this problem, a method was proposed by Kim, Keyes and Straub, where optimally designed generalized ensemble sampling was combined with replica exchange, and denoted generalized replica exchange method (gREM).more » This new technique uses parametrized effective sampling weights that lead to a unimodal energy distribution, transforming unstable states into stable ones. In the present study, the gREM, originally developed as a Monte Carlo algorithm, was implemented to work with molecular dynamics in an isobaric ensemble and coded into LAMMPS, a highly optimized open source molecular simulation package. Lastly, the method is illustrated in a study of the very strong solid/liquid transition in water.« less

  16. Generalized ensemble method applied to study systems with strong first order transitions

    NASA Astrophysics Data System (ADS)

    Małolepsza, E.; Kim, J.; Keyes, T.

    2015-09-01

    At strong first-order phase transitions, the entropy versus energy or, at constant pressure, enthalpy, exhibits convex behavior, and the statistical temperature curve correspondingly exhibits an S-loop or back-bending. In the canonical and isothermal-isobaric ensembles, with temperature as the control variable, the probability density functions become bimodal with peaks localized outside of the S-loop region. Inside, states are unstable, and as a result simulation of equilibrium phase coexistence becomes impossible. To overcome this problem, a method was proposed by Kim, Keyes and Straub [1], where optimally designed generalized ensemble sampling was combined with replica exchange, and denoted generalized replica exchange method (gREM). This new technique uses parametrized effective sampling weights that lead to a unimodal energy distribution, transforming unstable states into stable ones. In the present study, the gREM, originally developed as a Monte Carlo algorithm, was implemented to work with molecular dynamics in an isobaric ensemble and coded into LAMMPS, a highly optimized open source molecular simulation package. The method is illustrated in a study of the very strong solid/liquid transition in water.

  17. Multiple functional roles of the accessory I-domain of bacteriophage P22 coat protein revealed by NMR structure and cryoEM modeling

    PubMed Central

    Rizzo, Alessandro A.; Suhanovsky, Margaret M.; Baker, Matthew L.; Fraser, LaTasha C.R.; Jones, Lisa M.; Rempel, Don L.; Gross, Michael L.; Chiu, Wah; Alexandrescu, Andrei T.; Teschke, Carolyn M.

    2014-01-01

    SUMMARY Some capsid proteins built on the ubiquitous HK97-fold have accessory domains that impart specific functions. Bacteriophage P22 coat protein has a unique inserted I-domain. Two prior I-domain models from sub-nanometer cryoEM reconstructions differed substantially. Therefore, the NMR structure of the I-domain was determined, which also was used to improve cryoEM models of coat protein. The I-domain has an anti-parallel 6-stranded β-barrel fold, previously not observed in HK97-fold accessory domains. The D-loop, which is dynamic both in the isolated I-domain and intact monomeric coat protein, forms stabilizing salt bridges between adjacent capsomers in procapsids. A newly described S-loop is important for capsid size determination, likely through intra-subunit interactions. Ten of eighteen coat protein temperature-sensitive-folding substitutions are in the I-domain, indicating its importance in folding and stability. Several are found on a positively charged face of the β-barrel that anchors the I-domain to a negatively charged surface of the coat protein HK97-core. PMID:24836025

  18. Multiple functional roles of the accessory I-domain of bacteriophage P22 coat protein revealed by NMR structure and CryoEM modeling.

    PubMed

    Rizzo, Alessandro A; Suhanovsky, Margaret M; Baker, Matthew L; Fraser, LaTasha C R; Jones, Lisa M; Rempel, Don L; Gross, Michael L; Chiu, Wah; Alexandrescu, Andrei T; Teschke, Carolyn M

    2014-06-10

    Some capsid proteins built on the ubiquitous HK97-fold have accessory domains imparting specific functions. Bacteriophage P22 coat protein has a unique insertion domain (I-domain). Two prior I-domain models from subnanometer cryoelectron microscopy (cryoEM) reconstructions differed substantially. Therefore, the I-domain's nuclear magnetic resonance structure was determined and also used to improve cryoEM models of coat protein. The I-domain has an antiparallel six-stranded β-barrel fold, not previously observed in HK97-fold accessory domains. The D-loop, which is dynamic in the isolated I-domain and intact monomeric coat protein, forms stabilizing salt bridges between adjacent capsomers in procapsids. The S-loop is important for capsid size determination, likely through intrasubunit interactions. Ten of 18 coat protein temperature-sensitive-folding substitutions are in the I-domain, indicating its importance in folding and stability. Several are found on a positively charged face of the β-barrel that anchors the I-domain to a negatively charged surface of the coat protein HK97-core. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. The Six Track Scherzer Rolling Lift Bridge…Two double track spans ...

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

    The Six Track Scherzer Rolling Lift Bridge…Two double track spans closed. One double-track span open. Photocopy of plate xvi in Scherzer Rolling Lift Bridge Company, Scherzer Rolling Lift Bridges. - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  20. 75 FR 18058 - Safety Zone; Patapsco River, Northwest and Inner Harbors, Baltimore, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-09

    ... historic sloop-of-war USS CONSTELLATION on May 27, 2010. This action is necessary to provide for the safety... Baltimore, Maryland, to a point on the Patapsco River near the Fort McHenry National Monument and Historic Shrine in Baltimore, Maryland, and its return. This action will restrict vessel traffic in portions of...

  1. 77 FR 25592 - Safety Zone; Patapsco River, Northwest and Inner Harbors, Baltimore, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-01

    ... historic sloop-of-war USS CONSTELLATION on May 24, 2012. This action is necessary to provide for the safety... Baltimore, Maryland, to a point on the Patapsco River near the Fort McHenry National Monument and Historic Shrine in Baltimore, Maryland, and its return. This action will restrict vessel traffic in portions of...

  2. The Open Learning Object Model to Promote Open Educational Resources

    ERIC Educational Resources Information Center

    Fulantelli, Giovanni; Gentile, Manuel; Taibi, Davide; Allegra, Mario

    2008-01-01

    In this paper we present the results of research work, that forms part of the activities of the EU-funded project SLOOP: Sharing Learning Objects in an Open Perspective, aimed at encouraging the definition, development and management of Open Educational Resources based on the Learning Object paradigm (Wiley, 2000). We present a model of Open…

  3. 78 FR 56834 - Safety Zone; Patapsco River, Northwest and Inner Harbors; Baltimore, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-16

    ... historic sloop-of-war USS CONSTELLATION on September 26, 2013. If necessary, due to inclement weather, the..., due to inclement weather, the event will be rescheduled for October 3, 2013. The event is scheduled to... congestion along the planned route. In the event of inclement weather, the ``turn-around'' will be...

  4. Hydrographic surveys of the Missouri and Yellowstone Rivers at selected bridges and through Bismarck, North Dakota, during the 2011 flood

    USGS Publications Warehouse

    Densmore, Brenda K.; Strauch, Kellan R.; Dietsch, Benjamin J.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the North Dakota Department of Transportation and the North Dakota State Water Commission, completed hydrographic surveys at six Missouri River bridges and one Yellowstone River bridge during the 2011 flood of the Missouri River system. Bridges surveyed are located near the cities of Cartwright, Buford, Williston, Washburn, and Bismarck, N. Dak. The river in the vicinity of the bridges and the channel through the city of Bismarck, N. Dak., were surveyed. The hydrographic surveys were conducted using a high-resolution multibeam echosounder (MBES), the RESON SeaBatTM 7125, during June 6–9 and June 28–July 9, 2011. The surveyed area at each bridge site extended 820 feet upstream from the bridge to 820 feet downstream from the bridge. The surveyed reach through Bismarck consisted of 18 miles of the main channel wherever depth was sufficient. Results from these emergency surveys aided the North Dakota Department of Transportation in evaluating the structural integrity of the bridges during high-flow conditions. In addition, the sustained high flows made feasible the surveying of a large section of the normally shallow channel with the MBES. In general, results from sequential bridge surveys showed that as discharge increased between the first and second surveys at a given site, there was a general trend of channel scour. Locally, complex responses of scour in some areas and deposition in other areas of the channel were identified. Similarly, scour around bridge piers also showed complex responses to the increase in flow between the two surveys. Results for the survey area of the river channel through Bismarck show that, in general, scour occurred around river structures or where the river has tight bends and channel narrowing. The data collected during the surveys are provided electronically in two different file formats: comma delimited text and CARIS Spatial ArchiveTM (CSARTM) format.

  5. 78 FR 56609 - Drawbridge Operation Regulations; Reynolds Channel, Lawrence, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-13

    ... Regulations; Reynolds Channel, Lawrence, NY AGENCY: Coast Guard, DHS. ACTION: Notice canceling temporary... Beach Bridge, mile 0.4, across Reynolds Channel, at Lawrence, New York. The owner of the bridge, Nassau... published a temporary deviation entitled ``Drawbridge Operation Regulations; Reynolds Channel, Lawrence, NY...

  6. 77 FR 37316 - Drawbridge Operation Regulations; Reynolds Channel, Nassau, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-21

    ... Regulations; Reynolds Channel, Nassau, NY AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from... regulations governing the operation of the Long Beach Bridge, mile 4.7, across Reynolds Channel, at Nassau...: The Long Beach Bridge, across Reynolds Channel, mile 4.7, at Nassau, New York, has a vertical...

  7. 77 FR 50016 - Drawbridge Operation Regulation; Grassy Sound Channel, Middle Township, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ... Operation Regulation; Grassy Sound Channel, Middle Township, NJ AGENCY: Coast Guard, DHS. ACTION: Notice of... operating schedule that governs the Grassy Sound Channel (Ocean Drive) Bridge across the Grassy Sound... operating schedule to accommodate ``The Wild Half'' run. The Grassy Sound Channel (Ocean Drive) Bridge...

  8. 33 CFR 117.753 - Ship Channel, Great Egg Harbor Bay.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Ship Channel, Great Egg Harbor... SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.753 Ship Channel, Great Egg Harbor Bay. The draw of the S52 (Ship Channel) bridge, mile 0.5 between Somers Point and Ocean...

  9. 33 CFR 117.753 - Ship Channel, Great Egg Harbor Bay.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Ship Channel, Great Egg Harbor... SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.753 Ship Channel, Great Egg Harbor Bay. The draw of the S52 (Ship Channel) bridge, mile 0.5 between Somers Point and Ocean...

  10. 78 FR 48314 - Drawbridge Operation Regulation; Grassy Sound Channel, Middle Township, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ... Operation Regulation; Grassy Sound Channel, Middle Township, NJ AGENCY: Coast Guard, DHS. ACTION: Notice of... operating schedule that governs the Grassy Sound Channel Bridge (Ocean Drive) across Grassy Sound, mile 1.0..., the Grassy Sound Channel Bridge (Ocean Drive), at mile 1.0, at Middle Township, NJ is open on signal...

  11. River meander modeling of the Wabash River near the Interstate 64 Bridge near Grayville, Illinois

    USGS Publications Warehouse

    Lant, Jeremiah G.; Boldt, Justin A.

    2018-01-16

    Natural river channels continually evolve and change shape over time. As a result, channel evolution or migration can cause problems for bridge structures that are fixed in the flood plain. A once-stable bridge structure that was uninfluenced by a river’s shape could be encroached upon by a migrating river channel. The potential effect of the actively meandering Wabash River on the Interstate 64 Bridge at the border with Indiana near Grayville, Illinois, was studied using a river migration model called RVR Meander. RVR Meander is a toolbox that can be used to model river channel meander migration with physically based bank erosion methods. This study assesses the Wabash River meandering processes through predictive modeling of natural meandering over the next 100 years, climate change effects through increased river flows, and bank protection measures near the Interstate 64 Bridge.

  12. Channel evolution of the Hatchie River near the U.S. Highway 51 crossing in Lauderdale and Tipton counties, West Tennessee

    USGS Publications Warehouse

    Bryan, B.A.

    1989-01-01

    An investigation was conducted to describe the channel cross-section evolution near the bridge crossing of the Hatchie River at U.S. Highway 51 in Lauderdale and Tipton Counties, in West Tennessee. The study also included velocity and discharge distributions near the bridge crossing, and definition of streamflow duration and flood frequencies at the bridge site and comparison of these statistics with flows prior to the bridge collapse. Cross-section measurements at the site indicated that the channel was widening at a rate of 0.8 ft/year from 1931 through about 1975. The channel bed was stable at an elevation of about 235 ft. Construction of a south bound bridge in 1974 and 1975 reduced the effective flow width from about 4,000 to about 1,000 ft. Data collected from 1975 to 1981 indicated that the channel bed degraded to an elevation of about 230 ft and the widening rate increased to about 4.5 ft/year. The channel bed returned to approximately the pre-construction elevation of 235 ft as channel width increased. The widening rate decreased to about 1.8 ft/year from 1981 through 1989. Channel-geometry data indicated that recent channel morphology changes along the toe of the right bank have resulted in continued bank undercutting and bank failure. Cross-section geometry and flow-velocity distributions from measurements made from April 6 through 10, 1989, indicate that there is a high-flow meander pattern through this river reach and that the bridges are located at the point where the current strikes the right bank. (USGS)

  13. 44 CFR 72.3 - Fee schedule.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... previously; (6) Requests for LOMRs and PMRs based on projects involving bridges, culverts, or channels, or... involving new hydrologic information, bridges, culverts, or channels, or combinations thereof; and (11...

  14. 44 CFR 72.3 - Fee schedule.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... previously; (6) Requests for LOMRs and PMRs based on projects involving bridges, culverts, or channels, or... involving new hydrologic information, bridges, culverts, or channels, or combinations thereof; and (11...

  15. 44 CFR 72.3 - Fee schedule.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... previously; (6) Requests for LOMRs and PMRs based on projects involving bridges, culverts, or channels, or... involving new hydrologic information, bridges, culverts, or channels, or combinations thereof; and (11...

  16. 44 CFR 72.3 - Fee schedule.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... previously; (6) Requests for LOMRs and PMRs based on projects involving bridges, culverts, or channels, or... involving new hydrologic information, bridges, culverts, or channels, or combinations thereof; and (11...

  17. Summary and Comparison of Multiphase Streambed Scour Analysis at Selected Bridge Sites in Alaska

    USGS Publications Warehouse

    Conaway, Jeffrey S.

    2004-01-01

    The U.S. Geological Survey and the Alaska Department of Transportation and Public Facilities undertook a cooperative multiphase study of streambed scour at selected bridges in Alaska beginning in 1994. Of the 325 bridges analyzed for susceptibility to scour in the preliminary phase, 54 bridges were selected for a more intensive analysis that included site investigations. Cross-section geometry and hydraulic properties for each site in this study were determined from field surveys and bridge plans. Water-surface profiles were calculated for the 100- and 500-year floods using the Hydrologic Engineering Center?s River Analysis System and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths for the 100- and 500-year recurrence-interval discharges exceeded 5 feet at six bridges, and pier-scour depths exceeded 10 feet at 24 bridges. Complex pier-scour computations were made at 10 locations where the computed contraction-scour depths would expose pier footings. Pressure scour was evaluated at three bridges where the modeled flood water-surface elevations intersected the bridge structure. Site investigation at the 54 scour-critical bridges was used to evaluate the effectiveness of the preliminary scour analysis. Values for channel-flow angle of attack and approach-channel width were estimated from bridge survey plans for the preliminary study and were measured during a site investigation for this study. These two variables account for changes in scour depths between the preliminary analysis and subsequent reanalysis for most sites. Site investigation is needed for best estimates of scour at bridges with survey plans that indicate a channel-flow angle of attack and for locations where survey plans did not include sufficient channel geometry upstream of the bridge.

  18. A Conversion of Wheatstone Bridge to Current-Loop Signal Conditioning for Strain Gages

    NASA Technical Reports Server (NTRS)

    Anderson, Karl F.

    1995-01-01

    Current loop circuitry replaced Wheatstone bridge circuitry to signal-condition strain gage transducers in more than 350 data channels for two different test programs at NASA Dryden Flight Research Center. The uncorrected test data from current loop circuitry had a lower noise level than data from comparable Wheatstone bridge circuitry, were linear with respect to gage-resistance change, and were uninfluenced by varying lead-wire resistance. The current loop channels were easier for the technicians to set up, verify, and operate than equivalent Wheatstone bridge channels. Design choices and circuit details are presented in this paper in addition to operational experience.

  19. 78 FR 66265 - Drawbridge Operation Regulations; Reynolds Channel, Lawrence, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-05

    ... Regulations; Reynolds Channel, Lawrence, NY AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation... from the regulations governing the operation of the Atlantic Beach Bridge, mile 0.4, across Reynolds.... SUPPLEMENTARY INFORMATION: The Atlantic Beach Bridge, across Reynolds Channel, mile 0.4, at Lawrence, New York...

  20. 77 FR 70372 - Drawbridge Operation Regulation; Shark River (South Channel), Avon Township, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-26

    ... regulation that governs the opening of the S35 Bridge, mile 0.9, across Shark River (South Channel) at Avon... no longer a movable bridge, the regulation controlling the opening and closing of the bridge is no... jeopardizing the safety or security of people, places or vessels. 6. Unfunded Mandates Reform Act The Unfunded...

  1. AT&SF RAILROAD BRIDGE ACROSS ARROYO SECO CHANNEL AND PARKWAY. SEEN ...

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

    AT&SF RAILROAD BRIDGE ACROSS ARROYO SECO CHANNEL AND PARKWAY. SEEN FROM DEBS PARK IN SAME CAMERA LOCATION AS CA-265-13. NOTE FREEWAY 134 AT DISTANT RIGHT REAR. LOOKING 318°NW - Atchison, Topeka & Santa Fe Railroad Bridge, Spanning Arroyo Seco Parkway at parkway milepost 29.03, Los Angeles, Los Angeles County, CA

  2. 76 FR 11679 - Drawbridge Operation Regulation; Shark River (South Channel), Belmar, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-03

    ... Operation Regulation; Shark River (South Channel), Belmar, NJ AGENCY: Coast Guard, DHS. ACTION: Notice of... temporary deviation from the regulations governing the operation of the S71 Bridge across Shark River (South... Bridge, a bascule lift drawbridge, across Shark River (South Channel), at mile 0.8, in Belmar, NJ, has a...

  3. Alternative stream channel maintenance at bridge crossings : final report.

    DOT National Transportation Integrated Search

    2017-02-01

    Ohio Department of Transportation (ODOT) forces undertake routine and sometimes extensive maintenance of stream channels that impact the performance and safety of bridges. Unfortunately, county crews have limited options available to solve maintenanc...

  4. 11. VIEW OF ARROYO SECO CHANNEL SEEN FROM AVENUE 14 ...

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

    11. VIEW OF ARROYO SECO CHANNEL SEEN FROM AVENUE 14 BRIDGE. SAN FERNANDO ROAD BRIDGE AT CENTER. LOOKING 25° NNE. - Arroyo Seco Parkway, Figueroa Street Viaduct, Spanning Los Angeles River, Los Angeles, Los Angeles County, CA

  5. Streamflow and streambed scour in 2010 at bridge 339, Copper River, Alaska

    USGS Publications Warehouse

    Conaway, Jeffrey S.; Brabets, Timothy P.

    2011-01-01

    The distribution of the Copper River's discharge through the bridges was relatively stable until sometime between 1969-70 and 1982-85. The majority of the total Copper River discharge in 1969-70 passed through three bridges on the western side of the delta, but by 1982-1985, 25 to 62 percent of the flow passed through bridge 342 on the eastern side of the Copper River Delta. In 2004, only 8 percent of the flow passed through the western bridges, while 90 percent of the discharge flowed through two bridges on the eastern side of the delta. Migration of the river across the delta and redistribution of discharge has resulted in streambed scour at some bridges, overtopping of the road during high flows, prolonged highway closures, and formation of new channels through forests. Scour monitoring at the eastern bridges has recorded as much as 44 feet of fill at one pier and 33 feet of scour at another. In 2009, flow distribution began to shift from the larger bridge 342 to bridge 339. In 2010, flow in excess of four times the design discharge scoured the streambed at bridge 339 to a level such that constant on-site monitoring was required to evaluate the potential need for bridge closure. In 2010, instantaneous flow through bridge 339 was never less than 30 percent and was as high as 49 percent of the total Copper River discharge. The percentage of flow through bridge 339 decreased when the overall Copper River discharge increased. The increased discharge through bridge 339 is attributed to a shift in the approach channel 3,500 feet upstream. Bridge channel alignment and analysis of flow distribution as of October 2010 indicate these hydrologic hazards will persist in 2011.

  6. Two Salt Bridges Differentially Contribute to the Maintenance of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Channel Function*

    PubMed Central

    Cui, Guiying; Freeman, Cody S.; Knotts, Taylor; Prince, Chengyu Z.; Kuang, Christopher; McCarty, Nael A.

    2013-01-01

    Previous studies have identified two salt bridges in human CFTR chloride ion channels, Arg352-Asp993 and Arg347-Asp924, that are required for normal channel function. In the present study, we determined how the two salt bridges cooperate to maintain the open pore architecture of CFTR. Our data suggest that Arg347 not only interacts with Asp924 but also interacts with Asp993. The tripartite interaction Arg347-Asp924-Asp993 mainly contributes to maintaining a stable s2 open subconductance state. The Arg352-Asp993 salt bridge, in contrast, is involved in stabilizing both the s2 and full (f) open conductance states, with the main contribution being to the f state. The s1 subconductance state does not require either salt bridge. In confirmation of the role of Arg352 and Asp993, channels bearing cysteines at these sites could be latched into a full open state using the bifunctional cross-linker 1,2-ethanediyl bismethanethiosulfonate, but only when applied in the open state. Channels remained latched open even after washout of ATP. The results suggest that these interacting residues contribute differently to stabilizing the open pore in different phases of the gating cycle. PMID:23709221

  7. 75 FR 12688 - Drawbridge Operation Regulations; Long Island, New York Inland Waterway from East Rockaway Inlet...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-17

    ... operation of the Wreck Lead Railroad Bridge across Reynolds Channel, mile 4.4, New York. This deviation... INFORMATION: The Wreck Lead Railroad Bridge across Reynolds Channel at mile 4.4, New York, has a vertical...

  8. 76 FR 35978 - Drawbridge Operation Regulations; Long Island, New York Inland Waterway From East Rockaway Inlet...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... regulation governing the operation of the Long Beach Bridge at mile 4.7, across Reynolds Channel at Nassau...-9826. SUPPLEMENTARY INFORMATION: The Long Beach Bridge, across Reynolds Channel at mile 4.7, at Nassau...

  9. Lateral movement and stability of channel banks near four highway crossings in southwestern Mississippi

    USGS Publications Warehouse

    Turnipseed, D. Phil

    1994-01-01

    Channel meandering in alluvial streams has caused localized channel instability that has resulted in bridge failure and loss of human life in Mississippi. The U.S. Geological Survey, in coopera- tion with the Mississippi Department of Transpor- tation, conducted a study to develop a better methodology for defining and estimating channel meandering. For this report, river reaches near four bridge sites with current lateral movement of channel banks were selected for study. The lateral movement of channel banks was studied by mapping meanders from aerial photographs taken at various times, evaluating available discharge measurements, and measuring existing channel geometry and soil strength properties at these sites. Rapid, unre- stricted meander cuts and sandy banks are charac- teristic of the sites. Lateral movement was signi- ficant upstream from all four sites, and only one bridge site did not have significant lateral channel-bank movement during the study period. The development of cutbanks and localized channel-bank erosion have caused unstable conditions at three of the sites. Maps of tops of channel indicate significant lateral movement of channel banks upstream and downstream of all four sites and near the bridges at three of four sites. No significant movement occurred at the U.S. Highway 98 crossing of the Bogue Chitto near Tylertown from 1941 to 1991 despite large floods in 1983 and 1990. Slope stability analyses indicated this site to be marginally stable. The maximum lateral movement indicated from maps of tops of channel banks was 680 feet of northward movement of the right (north) bank of the Homochitto River near the State Highway 33 crossing at Rosetta from 1941 to 1983.

  10. Rocket Research Presentation at the NACA's 1947 Inspection

    NASA Image and Video Library

    1947-10-21

    Researcher John Sloop briefs visitors on his latest rocket engine research during the 1947 Inspection at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The NACA had been hosting annual Aircraft Engineering Conferences, better known as Inspections, since 1926. Individuals from the manufacturing industry, military, and university settings were invited to tour the NACA laboratories. There were a series of stops on the tour, mostly at test facilities, where researchers would brief the group on the latest efforts in their particular field. The Inspections grew in size and scope over the years and by the mid-1940s required multiple days. The three-day 1947 Inspection was the first time the event was held at NACA Lewis. Over 800 scientists, industrialists, and military leaders attended the three-day event. Talks were given at the Altitude Wind Tunnel, Four Burner Area, Engine Research Building, and other facilities. An array of topics were discussed, including full-scale engine testing, ramjets, axial-flow compressors, turbojets, fuels, icing, and materials. The NACA Lewis staff and their families were able to view the same presentations after the Inspection was over. Sloop, a researcher in the Fuels and Thermodynamics Division, briefed visitors on NACA Lewis’ early research in rocket engine propellants, combustion, and cooling. This early NACA Lewis work led to the development of liquid hydrogen as a viable propellant in the late 1950s.

  11. Agar-based bridges as biocompatible candidates to provide guide cues in spinal cord injury repair.

    PubMed

    Martín-López, Eduardo; Darder, Margarita; Ruiz-Hitzky, Eduardo; Nieto Sampedro, Manuel

    2013-01-01

    Spinal bridge implants are strategic to provide growth surfaces for axonal regeneration after spinal cord injuries. The design of an appropriate substrate, one that is suitable for implantation, must involve careful testing of the biomaterial properties both in vitro and in vivo. The goal of this work was to test the structure, stability and biological response after spinal bridges implantation of several biopolymers, composed of mixtures of agar (AG), as structural matrix scaffold, with κ-carrageenan (Kc), gelatin (G), xanthan gum (Xn) and polysulfone (PS). Biopolymer structures were studied by environmental scanning electron microscopy, whereas the stability of gels was analyzed by in vitro degradation and swelling tests. The biocompatibility of these materials and their ability to promote cell growth and axonal regeneration were studied by implantation of spinal bridges containing empty linear channels in an acute rat spinal cord transection model at thoracic level (T8). All gel mixtures gave rise to porous structures and they were stables to degradation, excepting the AG+G mixture. Spinal bridges constructed from all mixtures were implanted during a month in adult rats. After this time a low host reaction occurred to all bridge materials as well as neurite and cell ingrowths through the empty channels. Neurites within the bridges were mostly peripheral sensory fibers such as those positive for CGRP, whereas there was a lack of regeneration of central axons crossing from the spinal tissue to bridges. Many of these neurites established closed contacts with non-myelin Schwann cells. The histological analysis revealed a high accumulation of collagen fibers within the channels. Unexpected was the apparent loss of channels linearity which affected the growth of neurites and cells, indicating the need for additional regeneration strategies and vertebrae bridge fixing.

  12. 3. This series of photographs (3 through 9) illustrates the ...

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

    3. This series of photographs (3 through 9) illustrates the operation of the swing bridge. In #3 the bridge is in its closed position. #3 4,5,&6 the boat whistles and requests passage. the bridge is closed to traffice. The bridge operator, stationed in the center of the tenders house at the center of the truss releases the pneumatic jack. The rollers beneath the deck. swing upward and the electric-powered turntable swings the bobtail drawn in the direction of the oncoming vessel. In #7 a tugboat enters the channel. In #8 a much-lightened ore carrier which has delivered its cargo to the steel mills upriver(note the high water mark), makes its way down-river towards Lake Erie. Such boats are too large to turn around on the narrow Cuyahoga, so they go out backwards, pulled by a tug. in #9 the the ore-carrier clears the channel. In #10 As soon as the boat clears the bridge, the bridge tender begins to close it. The bridge is opened in the direction of an oncoming vessel so that it can be closed even as the boat is leaving the channel; thus surface traffic on Center Street suffers the least possible interruption. - Center Street Swing Bridge, Southwest of Public Square, Cleveland, Cuyahoga County, OH

  13. Supply of large woody debris in a stream channel

    USGS Publications Warehouse

    Diehl, Timothy H.; Bryan, Bradley A.

    1993-01-01

    The amount of large woody debris that potentially could be transported to bridge sites was assessed in the basin of the West Harpeth River in Tennessee in the fall of 1992. The assessment was based on inspections of study sites at 12 bridges and examination of channel reaches between bridges. It involved estimating the amount of woody material at least 1.5 meters long, stored in the channel, and not rooted in soil. Study of multiple sites allowed estimation of the amount, characteristics, and sources of debris stored in the channel, and identification of geomorphic features of the channel associated with debris production. Woody debris is plentiful in the channel network, and much of the debris could be transported by a large flood. Tree trunks with attached root masses are the dominant large debris type. Death of these trees is primarily the result of bank erosion. Bank instability seems to be the basin characteristic most useful in identifying basins with a high potential for abundant production of debris.

  14. A four-disulphide-bridged toxin, with high affinity towards voltage-gated K+ channels, isolated from Heterometrus spinnifer (Scorpionidae) venom.

    PubMed

    Lebrun, B; Romi-Lebrun, R; Martin-Eauclaire, M F; Yasuda, A; Ishiguro, M; Oyama, Y; Pongs, O; Nakajima, T

    1997-11-15

    A new toxin, named HsTX1, has been identified in the venom of Heterometrus spinnifer (Scorpionidae), on the basis of its ability to block the rat Kv1.3 channels expressed in Xenopus oocytes. HsTX1 has been purified and characterized as a 34-residue peptide reticulated by four disulphide bridges. HsTX1 shares 53% and 59% sequence identity with Pandinus imperator toxin1 (Pi1) and maurotoxin, two recently isolated four-disulphide-bridged toxins, whereas it is only 32-47% identical with the other scorpion K+ channel toxins, reticulated by three disulphide bridges. The amidated and carboxylated forms of HsTX1 were synthesized chemically, and identity between the natural and the synthetic amidated peptides was proved by mass spectrometry, co-elution on C18 HPLC and blocking activity on the rat Kv1.3 channels. The disulphide bridge pattern was studied by (1) limited reduction-alkylation at acidic pH and (2) enzymic cleavage on an immobilized trypsin cartridge, both followed by mass and sequence analyses. Three of the disulphide bonds are connected as in the three-disulphide-bridged scorpion toxins, and the two extra half-cystine residues of HsTX1 are cross-linked, as in Pi1. These results, together with those of CD analysis, suggest that HsTX1 probably adopts the same general folding as all scorpion K+ channel toxins. HsTX1 is a potent inhibitor of the rat Kv1.3 channels (IC50 approx. 12 pM). HsTX1 does not compete with 125I-apamin for binding to its receptor site on rat brain synaptosomal membranes, but competes efficiently with 125I-kaliotoxin for binding to the voltage-gated K+ channels on the same preparation (IC50 approx. 1 pM).

  15. Efficient method for assessing channel instability near bridges

    USGS Publications Warehouse

    Robinson, Bret A.; Thompson, R.E.

    1993-01-01

    Efficient methods for data collection and processing are required to complete channel-instability assessments at 5,600 bridge sites in Indiana at an affordable cost and within a reasonable time frame while maintaining the quality of the assessments. To provide this needed efficiency and quality control, a data-collection form was developed that specifies the data to be collected and the order of data collection. This form represents a modification of previous forms that grouped variables according to type rather than by order of collection. Assessments completed during two field seasons showed that greater efficiency was achieved by using a fill-in-the-blank form that organizes the data to be recorded in a specified order: in the vehicle, from the roadway, in the upstream channel, under the bridge, and in the downstream channel.

  16. 75 FR 30747 - Drawbridge Operation Regulation; Curtis Creek, Baltimore, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... audio voice-warning device will announce bridge movement. The channel traffic lights will then... an audio voice-warning device will announce bridge movement. The channel traffic lights will then... shall provide and keep in good legible condition two board gauges painted white with black figures not...

  17. 33 CFR 118.110 - Daymarks and lateral lighting on bridges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

  18. 33 CFR 118.110 - Daymarks and lateral lighting on bridges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

  19. 33 CFR 118.110 - Daymarks and lateral lighting on bridges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

  20. 20. View southwest under bridge showing steel girder, cross beams, ...

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

    20. View southwest under bridge showing steel girder, cross beams, and bracing of bascule leaves. - Yellow Mill Bridge, Spanning Yellow Mill Channel at Stratford Avenue, Bridgeport, Fairfield County, CT

  1. Results of repeat bathymetric and velocimetric surveys at the Amelia Earhart Bridge on U.S. Highway 59 over the Missouri River at Atchison, Kansas, 2009-2013

    USGS Publications Warehouse

    Huizinga, Richard J.

    2013-01-01

    Bathymetric and velocimetric data were collected six times by the U.S. Geological Survey, in cooperation with the Kansas Department of Transportation, in the vicinity of Amelia Earhart Bridge on U.S. Highway 59 over the Missouri River at Atchison, Kansas. A multibeam echosounder mapping system and an acoustic Doppler current meter were used to obtain channel-bed elevations and depth-averaged velocities for a river reach approximately 2,300 feet long and extending across the active channel of the Missouri River. The bathymetric and velocimetric surveys provide a “snapshot” of the channel conditions at the time of each survey, and document changes to the channel-bed elevations and velocities during the course of construction of a new bridge for U.S. Highway 59 downstream from the Amelia Earhart Bridge. The baseline survey in June 2009 revealed substantial scour holes existed at the railroad bridge piers upstream from and at pier 10 of the Amelia Earhart Bridge, with mostly uniform flow and velocities throughout the study reach. After the construction of a trestle and cofferdam on the left (eastern) bank downstream from the Amelia Earhart Bridge, a survey on June 2, 2010, revealed scour holes with similar size and shape as the baseline for similar flow conditions, with slightly higher velocities and a more substantial contraction of flow near the bridges than the baseline. Subsequent surveys during flooding conditions in June 2010 and July 2011 revealed substantial scour near the bridges compared to the baseline survey caused by the contraction of flow; however, the larger flood in July 2011 resulted in less scour than in June 2010, partly because the removal of the cofferdam for pier 5 of the new bridge in March 2011 diminished the contraction near the bridges. Generally, the downstream part of the study reach exhibited varying amounts of scour in all of the surveys except the last when compared to the baseline. During the final survey, velocities throughout the study area were the lowest of all the surveys, resulting in overall deposition throughout the reach compared to the baseline survey—despite the presence of the trestle in the final survey. The multiple surveys at the Amelia Earhart Bridge document the effects of moderate- to high-flow conditions on scour, compounded by the effects of adding and removing a constriction in the channel. Additional factors such as pier shape and angle of approach flow also were documented.

  2. 1. SUMMER STREET BRIDGE. DRAW SPAN MOVES TOWARD VIEWER ON ...

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

    1. SUMMER STREET BRIDGE. DRAW SPAN MOVES TOWARD VIEWER ON TRACKS VISIBLE AT CENTER OF PHOTOGRAPH. - Summer Street Retractile Bridge, Spanning Fort Point Channel at Summer Street, Boston, Suffolk County, MA

  3. 78 FR 17097 - Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ...-AA00 Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ AGENCY: Coast Guard, DHS. ACTION... waters of Lake Havasu and the London Bridge Channel for the Lake Havasu Triathlon. This temporary safety... participants. The waterside swim course consists of 1500 meters in Lake Havasu and the London Bridge Channel...

  4. Implementing statistical analysis in multi-channel acoustic impact-echo testing of concrete bridge decks: Determining thresholds for delamination detection

    NASA Astrophysics Data System (ADS)

    Hendricks, Lorin; Spencer Guthrie, W.; Mazzeo, Brian

    2018-04-01

    An automated acoustic impact-echo testing device with seven channels has been developed for faster surveying of bridge decks. Due to potential variations in bridge deck overlay thickness, varying conditions between testing passes, and occasional imprecise equipment calibrations, a method that can account for variations in deck properties and testing conditions was necessary to correctly interpret the acoustic data. A new methodology involving statistical analyses was therefore developed. After acoustic impact-echo data are collected and analyzed, the results are normalized by the median for each channel, a Gaussian distribution is fit to the histogram of the data, and the Kullback-Leibler divergence test or Otsu's method is then used to determine the optimum threshold for differentiating between intact and delaminated concrete. The new methodology was successfully applied to individual channels of previously unusable acoustic impact-echo data obtained from a three-lane interstate bridge deck surfaced with a polymer overlay, and the resulting delamination map compared very favorably with the results of a manual deck sounding survey.

  5. 6. DETAIL VIEW OF NORTHEAST END OF BRIDGE, SHOWING ROCKER ...

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

    6. DETAIL VIEW OF NORTHEAST END OF BRIDGE, SHOWING ROCKER ARM PORTION OF BASCULE - Seddon Island Scherzer Rolling Lift Bridge, Spanning Garrison Channel from Tampa to Seddon Island, Tampa, Hillsborough County, FL

  6. 33 CFR 117.997 - Atlantic Intracoastal Waterway, South Branch of the Elizabeth River to the Albermarle and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... bridge and directly beneath the bridge with closed circuit cameras mounted on top of the bridge and with... movement, a warning alarm will sound until the bridge is seated and locked down or in the full open... bridge is seated and locked down. When the bridge is seated and locked down to vessels, the channel...

  7. Wind Tunnel Measurements for Flutter of a Long-Afterbody Bridge Deck

    PubMed Central

    Chen, Zeng-Shun; Zhang, Cheng; Wang, Xu; Ma, Cun-Ming

    2017-01-01

    Bridges are an important component of transportation. Flutter is a self-excited, large amplitude vibration, which may lead to collapse of bridges. It must be understood and avoided. This paper takes the Jianghai Channel Bridge, which is a significant part of the Hong Kong-Zhuhai-Macao Bridge, as an example to investigate the flutter of the bridge deck. Firstly, aerodynamic force models for flutter of bridges were introduced. Then, wind tunnel tests of the bridge deck during the construction and the operation stages, under different wind attack angles and wind velocities, were carried out using a high frequency base balance (HFBB) system and laser displacement sensors. From the tests, the static aerodynamic forces and flutter derivatives of the bridge deck were observed. Correspondingly, the critical flutter wind speeds of the bridge deck were determined based on the derivatives, and they are compared with the directly measured flutter speeds. Results show that the observed derivatives are reasonable and applicable. Furthermore, the critical wind speeds in the operation stage is smaller than those in the construction stage. Besides, the flutter instabilities of the bridge in the construction and the operation stages are good. This study helps guarantee the design and the construction of the Jianghai Channel Bridge, and advances the understanding of flutter of long afterbody bridge decks. PMID:28208773

  8. Wind Tunnel Measurements for Flutter of a Long-Afterbody Bridge Deck.

    PubMed

    Chen, Zeng-Shun; Zhang, Cheng; Wang, Xu; Ma, Cun-Ming

    2017-02-09

    Bridges are an important component of transportation. Flutter is a self-excited, large amplitude vibration, which may lead to collapse of bridges. It must be understood and avoided. This paper takes the Jianghai Channel Bridge, which is a significant part of the Hong Kong-Zhuhai-Macao Bridge, as an example to investigate the flutter of the bridge deck. Firstly, aerodynamic force models for flutter of bridges were introduced. Then, wind tunnel tests of the bridge deck during the construction and the operation stages, under different wind attack angles and wind velocities, were carried out using a high frequency base balance (HFBB) system and laser displacement sensors. From the tests, the static aerodynamic forces and flutter derivatives of the bridge deck were observed. Correspondingly, the critical flutter wind speeds of the bridge deck were determined based on the derivatives, and they are compared with the directly measured flutter speeds. Results show that the observed derivatives are reasonable and applicable. Furthermore, the critical wind speeds in the operation stage is smaller than those in the construction stage. Besides, the flutter instabilities of the bridge in the construction and the operation stages are good. This study helps guarantee the design and the construction of the Jianghai Channel Bridge, and advances the understanding of flutter of long afterbody bridge decks.

  9. Measurement of bridge scour at the SR-32 crossing of the Sacramento River at Hamilton City, California, 1987-92

    USGS Publications Warehouse

    Blodgett, J.C.; Harris, Carroll D.; ,

    1993-01-01

    A study of the State Route 32 crossing of the Sacramento River near Hamilton City, California, is being made to determine those channel and bridge factors that contribute to scour at the site. Three types of scour data have been measured-channel bed (natural) scour, constriction (general) scour, and local (bridge-pier induced) scour. During the years 1979-93, a maximum of 3.4 ft of channel bed scour, with a mean of 1.4 ft, has been measured. Constriction scour, which may include channel bed scour, has been measured at the site nine times during the years 1987-92. The calculated amount of constriction scour ranged from 0.2 to 3.0 ft, assuming the reference is the mean bed elevation. Local scour was measured four times at the site in 1991 and 1992 and ranged from -2.1 (fill) to 11.6 ft , with the calculated amounts dependent on the bed reference elevation and method of computation used. Surveys of the channel bed near the bridge piers indicate the horizontal location of lowest bed elevation (maximum depth of scour) may vary at least 17 ft between different surveys at the same pier and most frequently is located downstream from the upstream face of the pier.

  10. Quality control and quality assurance plan for bridge channel-stability assessments in Massachusetts

    USGS Publications Warehouse

    Parker, Gene W.; Pinson, Harlow

    1993-01-01

    A quality control and quality assurance plan has been implemented as part of the Massachusetts bridge scour and channel-stability assessment program. This program is being conducted by the U.S. Geological Survey, Massachusetts-Rhode Island District, in cooperation with the Massachusetts Highway Department. Project personnel training, data-integrity verification, and new data-management technologies are being utilized in the channel-stability assessment process to improve current data-collection and management techniques. An automated data-collection procedure has been implemented to standardize channel-stability assessments on a regular basis within the State. An object-oriented data structure and new image management tools are used to produce a data base enabling management of multiple data object classes. Data will be reviewed by assessors and data base managers before being merged into a master bridge-scour data base, which includes automated data-verification routines.

  11. Short-term evaluation of a bridge cable using acoustic emission sensors.

    DOT National Transportation Integrated Search

    2010-05-01

    The Varina-Enon Bridge carries I-295 across the James River and crosses over the shipping channel that leads to the Richmond (Virginia) Marine Terminal. The bridge is a cable-stayed bridge that was opened to traffic in July 1990. It has 150 ft of ver...

  12. 75 FR 38923 - Regulated Navigation Area: Niantic Railroad Bridge Construction, Niantic, CT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ...-AA11 Regulated Navigation Area: Niantic Railroad Bridge Construction, Niantic, CT AGENCY: Coast Guard... Niantic River Channel under and surrounding the Amtrak Railroad Bridge that crosses Niantic Bay in the... on the navigable waters during the construction of the Niantic Railroad Bridge. DATES: This rule is...

  13. 22. View of Clark Fork Vehicle Bridge facing downwest side. ...

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

    22. View of Clark Fork Vehicle Bridge facing down-west side. Looking at road deck and vertical laced channel. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

  14. 44. Detail, bridge land span outboard girder brackets carrying utility ...

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

    44. Detail, bridge land span outboard girder brackets carrying utility conduit. Structure rests on granite blocks mounted on granite piers. - Broadway Bridge, Spanning Foundry Street, MBTA Yard, Fort Point Channel, & Lehigh Street, Boston, Suffolk County, MA

  15. Backwater effects of Piers in Subcritical Flow

    DOT National Transportation Integrated Search

    2001-10-01

    Construction or renovation of bridge structures may require placement of bridge piers within the channel or floodplain of natural waterways. These piers will obstruct the flow and may cause an increase in water levels upstream of the bridge structure...

  16. 33 CFR 165.1110 - Security Zone: Coronado Bay Bridge, San Diego, CA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Bridge, San Diego, CA. 165.1110 Section 165.1110 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.1110 Security Zone: Coronado Bay Bridge, San Diego, CA. (a) Location. All navigable waters of San... pilings of the Coronado Bay Bridge. These security zones will not restrict the main navigational channel...

  17. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... six inches square. If the visibility required is more than one-half mile, the panels must be at least 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge lighting. Lateral significant red triangles and green square retroreflective panels shall be used. The...

  18. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... six inches square. If the visibility required is more than one-half mile, the panels must be at least 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge lighting. Lateral significant red triangles and green square retroreflective panels shall be used. The...

  19. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... six inches square. If the visibility required is more than one-half mile, the panels must be at least 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge lighting. Lateral significant red triangles and green square retroreflective panels shall be used. The...

  20. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... six inches square. If the visibility required is more than one-half mile, the panels must be at least 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge lighting. Lateral significant red triangles and green square retroreflective panels shall be used. The...

  1. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... six inches square. If the visibility required is more than one-half mile, the panels must be at least 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge lighting. Lateral significant red triangles and green square retroreflective panels shall be used. The...

  2. 33 CFR 165.1110 - Security Zone: Coronado Bay Bridge, San Diego, CA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Bridge, San Diego, CA. 165.1110 Section 165.1110 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.1110 Security Zone: Coronado Bay Bridge, San Diego, CA. (a) Location. All navigable waters of San... pilings of the Coronado Bay Bridge. These security zones will not restrict the main navigational channel...

  3. 76 FR 57910 - Regulated Navigation Area; Route 24 Bridge Construction, Tiverton and Portsmouth, RI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-19

    ...-AA11 Regulated Navigation Area; Route 24 Bridge Construction, Tiverton and Portsmouth, RI AGENCY: Coast... surrounding construction of the new Route 24 bridge that crosses the Sakonnet River between Tiverton and... channel beneath the bridge, speed restrictions, and suspension of all vessel traffic within the RNA during...

  4. 23. View of Clark Fork Vehicle Bridge facing upwest side. ...

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

    23. View of Clark Fork Vehicle Bridge facing up-west side. Looking at structural connection of top chord, vertical laced channel and diagonal bars. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

  5. 6. VIEW OF THE EASTERN BRIDGE ELEVATION, SHOWING CENTRAL PIER ...

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

    6. VIEW OF THE EASTERN BRIDGE ELEVATION, SHOWING CENTRAL PIER AND ASSOCIATED SUPERSTRUCTURE, AND CANTILEVERED NORTHERN TRUSS SECTION. NOTE THE JOIN BETWEEN EYE-BAR (LEFT) AND RIVETED CHANNEL (RIGHT) LOWER BRIDGE CHORDS AT CENTER LEFT OF PHOTOGRAPH. FACING NORTH. - Coverts Crossing Bridge, Spanning Mahoning River along Township Route 372 (Covert Road), New Castle, Lawrence County, PA

  6. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

  7. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

  8. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

  9. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

  10. Evaluation of streambed scour at bridges over tidal waterways in Alaska

    USGS Publications Warehouse

    Conaway, Jeffrey S.; Schauer, Paul V.

    2012-01-01

    The potential for streambed scour was evaluated at 41 bridges that cross tidal waterways in Alaska. These bridges are subject to several coastal and riverine processes that have the potential, individually or in combination, to induce streambed scour or to damage the structure or adjacent channel. The proximity of a bridge to the ocean and water-surface elevation and velocity data collected over a tidal cycle were criteria used to identify the flow regime at each bridge, whether tidal, riverine, or mixed, that had the greatest potential to induce streambed scour. Water-surface elevations measured through at least one tide cycle at 32 bridges were correlated to water levels at the nearest tide station. Asymmetry of the tidal portion of the hydrograph during the outgoing tide at 12 bridges indicated that riverine flows were stored upstream of the bridge during the tidal exchange. This scenario results in greater discharges and velocities during the outgoing tide compared to those on the incoming tide. Velocity data were collected during outgoing tides at 10 bridges that experienced complete flow reversals, and measured velocities during the outgoing tide exceeded the critical velocity required to initiate sediment transport at three sites. The primary risk for streambed scour at most of the sites considered in this study is from riverine flows rather than tidal fluctuations. A scour evaluation for riverine flow was completed at 35 bridges. Scour from riverine flow was not the primary risk for six tidally-controlled bridges and therefore not evaluated at those sites. Field data including channel cross sections, a discharge measurement, and a water-surface slope were collected at the 35 bridges. Channel instability was identified at 14 bridges where measurable scour and or fill were noted in repeated surveys of channel cross sections at the bridge. Water-surface profiles for the 1-percent annual exceedance probability discharge were calculated by using the Hydrologic Engineering Center’s River Analysis System model, and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths were greater than 2.0 feet at five bridges and computed pier-scour depths were 4.0 feet or greater at 15 bridges. The potential for streambed scour by both coastal and riverine processes at the bridges considered in this study were evaluated, ranked, and summed to determine a cumulative risk factor for each bridge. Possible factors that could mitigate the scour risks were investigated at 22 bridges that had high individual or cumulative rankings. Mitigating factors such as piers founded in bedrock, deep pier foundations relative to scour depths, and lack of observed scour during field measurements were documented for 13 sites, but additional study and monitoring is needed to better quantify the streambed scour potential for nine sites. Three bridges prone to being affected by storm surges will require more data collection and possibly complex hydrodynamic modeling to accurately quantify the streambed scour potential. Continuous monitoring of water-surface and streambed elevation at one or more piers is needed for two bridges to better understand the tidal and riverine influences on streambed scour.

  11. Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2013–15

    USGS Publications Warehouse

    Beebee, Robin A.; Dworsky, Karenth L.; Knopp, Schyler J.

    2017-12-27

    Streambed scour potential was evaluated at 52 river- and stream-spanning bridges in Alaska that lack a quantitative scour analysis or have unknown foundation details. All sites were evaluated for stream stability and long-term scour potential. Contraction scour and abutment scour were calculated for 52 bridges, and pier scour was calculated for 11 bridges that had piers. Vertical contraction (pressure flow) scour was calculated for sites where the modeled water surface was higher than the superstructure of the bridge. In most cases, hydraulic models of the 1- and 0.2-percent annual exceedance probability floods (also known as the 100- and 500-year floods, respectively) were used to derive hydraulic variables for the scour calculations. Alternate flood values were used in scour calculations for sites where smaller floods overtopped a bridge or where standard flood-frequency estimation techniques did not apply. Scour also was calculated for large recorded floods at 13 sites.Channel instability at 11 sites was related to human activities (in-channel mining, dredging, and channel relocation). Eight of the dredged sites are located on active unstable alluvial fans and were graded to protect infrastructure. The trend toward aggradation during major floods at these sites reduces confidence in scour estimates.Vertical contraction and pressure flow occurred during the 0.2-percent or smaller annual exceedance probability floods at eight sites. Contraction scour exceeded 5 feet (ft) at four sites, and total scour at piers (pier scour plus contraction scour) exceeded 5 ft at four sites. Debris accumulation increased calculated pier scour at six sites by an average of 2.4 ft. Total scour at abutments exceeded 5 ft at 10 sites. Scour estimates seemed excessive at two piers where equations did not account for channel armoring, and at four abutments where failure of the embankment and attendant channel widening would reduce scour.

  12. 12. DETAIL VIEW OF BRIDGE, SHOWING SPRING LINE OF SPANS ...

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

    12. DETAIL VIEW OF BRIDGE, SHOWING SPRING LINE OF SPANS FROM CROWN OF MID-CHANNEL PIER, PAIRED COLUMNS SUPPORTING DECK, ARCHED WINDOW RAILING, LOOKING WEST-NORTHWEST FROM EUREKA SOUTHERN RAILROAD BRIDGE. CABLES VISIBLE IN BACKGROUND ARE EARTHQUAKE RESTRAINERS RETROFITTED TO 1952 HIGHWAY BRIDGE, WHICH FUNCTIONED AS DESIGNED IN APRIL 1992 TEMBLOR - Van Duzen River Bridge, Spanning Van Duzen River at CA State Highway 101, Alton, Humboldt County, CA

  13. Structural evaluation of the John A. Roebling Suspension Bridge : element level analysis.

    DOT National Transportation Integrated Search

    2008-07-01

    The primary objective of the structural evaluation of the John A. Roebling Bridge is to determine the maximum allowable gross vehicle weight (GVW) that can be carried by the bridge deck structural elements such as the open steel grid deck, channels, ...

  14. Reduced channel conveyance on the Wichita River at Wichita Falls, Texas, 1900-2009

    USGS Publications Warehouse

    Winters, Karl; Baldys, Stanley; Schreiber, Russell

    2010-01-01

    Recent floods on the Wichita River at Wichita Falls, Texas, have reached higher stages compared to historical floods of similar magnitude discharges. The U.S. Geological Survey (USGS) has operated streamflow-gaging station 07312500 Wichita River at Wichita Falls, Tex., since 1938 and flood measurements near the location of the present gage were first made in 1900. Floods recorded in 2007 and 2008 at this gaging station, including the record flood of June 30, 2007, reached higher stages compared to historical floods before 1972 of similar peak discharges. For flood measurements made at stages of more than 18 feet, peak stages were about 1 to 3 feet higher compared to peak stages of similar peak discharges measured before 1972. Flood measurements made at stages of more than 18 feet also indicate a decrease in the measured mean velocity from about 3.5 to about 2.0 feet per second from 1941 to 2008. The increase in stage and decrease in streamflow velocity for similar magnitude floods indicates channel conveyance has decreased over time. A study to investigate the causes of reduced channel conveyance in the Wichita River reach from Loop 11 downstream to River Road in Wichita Falls was done by the USGS in cooperation with the City of Wichita Falls. Historical photographs indicate substantial growth of riparian vegetation downstream from Loop 11 between 1950 and 2009. Aerial photographs taken between 1950 and 2008 also indicate an increase in riparian vegetation. Twenty-five channel cross sections were surveyed by the USGS in this reach in 2009. These cross sections were located at bridge crossings or collocated with channel cross sections previously surveyed in 1986 for use in a floodplain mapping study by the Federal Emergency Management Agency. Four channel cross sections 3,400 to 11,900 feet downstream from Martin Luther King Jr. Boulevard indicate narrowing of the channel. The remaining channel cross sections surveyed in 2009 by the USGS compared favorably with cross sections surveyed in 1986 for the Federal Emergency Management Agency, with no substantial differences noted. Comparison of channel cross sections surveyed in 2009 to those from historic bridge plans indicate no change in cross section has occurred at most of the bridges from Loop 11 downstream to River Road in Wichita Falls, except for obstructions noted at the Scott Avenue bridge and Martin Luther King Jr. bridge. Although obstructions in the channel at these bridges only partially block flow, they could also be contributing to reduced channel conveyance. Step-backwater profiles were used by the USGS to verify channel roughness. The main channel roughness coefficients (Manning's n values) from 2009 surveys were virtually unchanged from those used in a 1991 hydraulic model done for the Federal Emergency Management Agency. The average overbank roughness coefficient (Manning's n value) was 0.15, more than double the value of 0.06 used in the 1991 hydraulic model. Increased overbank vegetation has resulted in higher stages conveying the same amount of discharge, particularly for discharges more than 4,000 cubic feet per second.

  15. Detailed scour measurements around a debris accumulation

    USGS Publications Warehouse

    Mueller, David S.; Parola, Arthur C.

    1998-01-01

    Detailed scour measurements were made at Farm-Market 2004 over the Brazos River near Lake Jackson, Tex. during flooding in October 1994. Woody debris accumulations on bents 6, 7, and 8 obstructed flow through the bridge, causing scour of the streambed. Measurements at the site included three-dimensional velocities, channel bathymetry, water-surface elevations, water-surface slope, and discharge. Channel geometry upstream from the bridge caused approach conditions to be nonuniform.

  16. A DS-UWB Cognitive Radio System Based on Bridge Function Smart Codes

    NASA Astrophysics Data System (ADS)

    Xu, Yafei; Hong, Sheng; Zhao, Guodong; Zhang, Fengyuan; di, Jinshan; Zhang, Qishan

    This paper proposes a direct-sequence UWB Gaussian pulse of cognitive radio systems based on bridge function smart sequence matrix and the Gaussian pulse. As the system uses the spreading sequence code, that is the bridge function smart code sequence, the zero correlation zones (ZCZs) which the bridge function sequences' auto-correlation functions had, could reduce multipath fading of the pulse interference. The Modulated channel signal was sent into the IEEE 802.15.3a UWB channel. We analysis the ZCZs's inhibition to the interference multipath interference (MPI), as one of the main system sources interferences. The simulation in SIMULINK/MATLAB is described in detail. The result shows the system has better performance by comparison with that employing Walsh sequence square matrix, and it was verified by the formula in principle.

  17. River sedimentation and channel bed characteristics in northern Ethiopia

    NASA Astrophysics Data System (ADS)

    Demissie, Biadgilgn; Billi, Paolo; Frankl, Amaury; Haile, Mitiku; Lanckriet, Sil; Nyssen, Jan

    2016-04-01

    Excessive sedimentation and flood hazard are common in ephemeral streams which are characterized by flashy floods. The purposes of this study was to investigate the temporal variability of bio-climatic factors in controlling sediment supply to downstream channel reaches and the effect of bridges on local hydro-geomorphic conditions in causing the excess sedimentation and flood hazard in ephemeral rivers of the Raya graben (northern Ethiopia). Normalized Difference Vegetation Index (NDVI) was analyzed for the study area using Landsat imageries of 1972, 1986, 2000, 2005, 2010, and 2012). Middle term, 1993-2011, daily rainfall data of three meteorological stations, namely, Alamata, Korem and Maychew, were considered to analyse the temporal trends and to calculate the return time intervals of rainfall intensity in 24 hours for 2, 5, 10 and 20 years using the log-normal and the Gumbel extreme events method. Streambed gradient and bed material grain size were measured in 22 river reaches (at bridges and upstream). In the study catchments, the maximum NDVI values were recorded in the time interval from 2000 to 2010, i.e. the decade during which the study bridges experienced the most severe excess sedimentation problems. The time series analysis for a few rainfall parameters do not show any evidence of rainfall pattern accountable for an increase in sediment delivery from the headwaters nor for the generation of higher floods with larger bedload transport capacities. Stream bed gradient and bed material grain size data were measured in order to investigate the effect of the marked decrease in width from the wide upstream channels to the narrow recently constructed bridges. The study found the narrowing of the channels due to the bridges as the main cause of the thick sedimentation that has been clogging the study bridges and increasing the frequency of overbank flows during the last 15 years. Key terms: sedimentation, ephemeral streams, sediment size, bridge clogging

  18. View of substructure of Sixth Street Bridge overcrossing of Los ...

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

    View of substructure of Sixth Street Bridge overcrossing of Los Angeles River. Looking west. Note dark hole at lower with is access ramp to river channel seen in HAER CA-176-56 - Sixth Street Bridge, Spanning 101 Freeway at Sixth Street, Los Angeles, Los Angeles County, CA

  19. Estimates of bridge scour at two sites on the Virgin River, southeastern Nevada, using a sediment-transport model and historical geomorphic data

    USGS Publications Warehouse

    Hilmes, M.M.; Vaill, J.E.

    1997-01-01

    A bridge-scour study by the U.S. Geological Survey, in cooperation with the Nevada Department of Transportation, began in April 1996 to evaluate the Mesquite, Nevada, and Riverside, Nevada, bridges on the lower Virgin River using a sediment-transport model and historical geomorphic data. The BRIdge Stream Tube model for Alluvial River Simulation (BRI-STARS) was used to estimate bridge scour. The model was first calibrated using data for the Virgin River flood of March 12, 1995. Surveyed channel-geometry data were available at 11 cross sections for dates before and after the March 1995 flood to allow for evaluation of the model results. The model estimated the thalweg altitude within plus or minus 1 meter at 10 of the 11 cross sections. The calibrated model then was used to estimate the contraction, channel, pier, and total scour for synthesized hydrographs for 100- and 500-year floods at the two bridge sites. The estimated maximum total scour at the Mesquite bridge was 1.30 meters for the 100-year flood and 1.32 meters for the 500-year flood. The maximum total scour at the Riverside bridge was 1.90 meters for the 100-year flood and 2.01 meters for the 500-year flood. General scour was evaluated using stage-discharge relations at nearby streamflow-gaging stations, 1993-95 channel-geometry data, and channel-geometry data for the 100- and 500-year floods. On the basis of stage and discharge at the Littlefield, Arizona, gaging station, no long-term trend in aggradation or degradation was found. However, several cycles of aggradation and degradation had occurred during the period of record; the difference between the highest and lowest stage was 0.87 meter for a chosen low-flow discharge of 5.66 cubic meters per second for 1929-95. The value of 0.87 meter is probably the best estimate of general scour. The cross sections had an average scour depth of 0.07 meter between 1993 and 1994 and 0.16 meter between 1994 and 1995. The model simulated little general scour for the 100- and 500-year floods at the cross sections and did not give a good estimate of general scour, probably because the duration (days) of the floods used in the model was relatively short when compared with the duration (months or years) of geomorphic processes that influence long-term aggradation or degradation. Historical geomorphic changes of the Virgin River at the bridge sites and the causes of those changes were documented using aerial photographs from 1938-95 and other historical information. The Virgin River has become narrower and more sinuous through time, the vegetation on the flood plain has increased, and the channel has shifted laterally many times. The processes associated with these channel changes were found to be long-term changes in precipitation and streamflow; the duration, magnitude, and timing of floods; sediment-transport characteristics; channel avulsion; changes in density of vegetation; and anthropogenic influences.

  20. Structure-correlated diffusion anisotropy in nanoporous channel networks by Monte Carlo simulations and percolation theory

    NASA Astrophysics Data System (ADS)

    Kondrashova, Daria; Valiullin, Rustem; Kärger, Jörg; Bunde, Armin

    2017-07-01

    Nanoporous silicon consisting of tubular pores imbedded in a silicon matrix has found many technological applications and provides a useful model system for studying phase transitions under confinement. Recently, a model for mass transfer in these materials has been elaborated [Kondrashova et al., Sci. Rep. 7, 40207 (2017)], which assumes that adjacent channels can be connected by "bridges" (with probability pbridge) which allows diffusion perpendicular to the channels. Along the channels, diffusion can be slowed down by "necks" which occur with probability pneck. In this paper we use Monte-Carlo simulations to study diffusion along the channels and perpendicular to them, as a function of pbridge and pneck, and find remarkable correlations between the diffusivities in longitudinal and radial directions. For clarifying the diffusivity in radial direction, which is governed by the concentration of bridges, we applied percolation theory. We determine analytically how the critical concentration of bridges depends on the size of the system and show that it approaches zero in the thermodynamic limit. Our analysis suggests that the critical properties of the model, including the diffusivity in radial direction, are in the universality class of two-dimensional lattice percolation, which is confirmed by our numerical study.

  1. 12. Photocopy of drawing (this photograph is an 8''x 10''contact ...

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

    12. Photocopy of drawing (this photograph is an 8''x 10''contact print; September, 1986 as built drawing by D. Monclova, in possession of the Highway Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Santiago (sic) Channel, Route no. 2 km. 75.50, Arecibo, P.R. Bridge no. 53. No. 2 of 2. - Puente del Cano Carate, Spanning Cano Carate Channel, Arecibo, Arecibo Municipio, PR

  2. 76 FR 14279 - Drawbridge Operation Regulation; Grassy Sound Channel, Middle Township, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    ... Operation Regulation; Grassy Sound Channel, Middle Township, NJ AGENCY: Coast Guard, DHS. ACTION: Notice of... temporary deviation from the regulations governing the operation of the Grassy Sound Channel Bridge across the Grassy Sound Channel, mile 1.0, at Middle Township, NJ. The deviation is necessary to facilitate...

  3. 47 CFR 80.102 - Radiotelephone station identification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... for more than 15 minutes. When public correspondence is being exchanged with a ship or aircraft... use of the name of the bridge in lieu of the call sign. (c) Ship stations transmitting on any authorized VHF bridge-to-bridge channel may be identified by the name of the ship in lieu of the call sign...

  4. 47 CFR 80.102 - Radiotelephone station identification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... for more than 15 minutes. When public correspondence is being exchanged with a ship or aircraft... use of the name of the bridge in lieu of the call sign. (c) Ship stations transmitting on any authorized VHF bridge-to-bridge channel may be identified by the name of the ship in lieu of the call sign...

  5. 47 CFR 80.102 - Radiotelephone station identification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... for more than 15 minutes. When public correspondence is being exchanged with a ship or aircraft... use of the name of the bridge in lieu of the call sign. (c) Ship stations transmitting on any authorized VHF bridge-to-bridge channel may be identified by the name of the ship in lieu of the call sign...

  6. 47 CFR 80.102 - Radiotelephone station identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... for more than 15 minutes. When public correspondence is being exchanged with a ship or aircraft... use of the name of the bridge in lieu of the call sign. (c) Ship stations transmitting on any authorized VHF bridge-to-bridge channel may be identified by the name of the ship in lieu of the call sign...

  7. 47 CFR 80.102 - Radiotelephone station identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... for more than 15 minutes. When public correspondence is being exchanged with a ship or aircraft... use of the name of the bridge in lieu of the call sign. (c) Ship stations transmitting on any authorized VHF bridge-to-bridge channel may be identified by the name of the ship in lieu of the call sign...

  8. 77 FR 57022 - Drawbridge Operation Regulation; Shark River, Avon, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-17

    ... across the Shark River (South Channel), at Avon Township, NJ. This deviation is necessary to facilitate... River, mile 0.9, is a bascule lift Bridge, in Avon Township, NJ, and has a vertical clearance in the... Township, NJ, the draws of these two bridges will also be restricted under this deviation. These bridges...

  9. 78 FR 77591 - Drawbridge Operation Regulation; Shark River, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ..., NJ. The deviation is necessary to facilitate the replacement of motor seals and instrumentation on... motor seals and instrumentation on the bridge. The Route 71 Bridge across Shark River (South Channel...

  10. A Highly Conserved Salt Bridge Stabilizes the Kinked Conformation of β2,3-Sheet Essential for Channel Function of P2X4 Receptors.

    PubMed

    Zhao, Wen-Shan; Sun, Meng-Yang; Sun, Liang-Fei; Liu, Yan; Yang, Yang; Huang, Li-Dong; Fan, Ying-Zhe; Cheng, Xiao-Yang; Cao, Peng; Hu, You-Min; Li, Lingyong; Tian, Yun; Wang, Rui; Yu, Ye

    2016-04-08

    Significant progress has been made in understanding the roles of crucial residues/motifs in the channel function of P2X receptors during the pre-structure era. The recent structural determination of P2X receptors allows us to reevaluate the role of those residues/motifs. Residues Arg-309 and Asp-85 (rat P2X4 numbering) are highly conserved throughout the P2X family and were involved in loss-of-function polymorphism in human P2X receptors. Previous studies proposed that they participated in direct ATP binding. However, the crystal structure of P2X demonstrated that those two residues form an intersubunit salt bridge located far away from the ATP-binding site. Therefore, it is necessary to reevaluate the role of this salt bridge in P2X receptors. Here, we suggest the crucial role of this structural element both in protein stability and in channel gating rather than direct ATP interaction and channel assembly. Combining mutagenesis, charge swap, and disulfide cross-linking, we revealed the stringent requirement of this salt bridge in normal P2X4 channel function. This salt bridge may contribute to stabilizing the bending conformation of the β2,3-sheet that is structurally coupled with this salt bridge and the α2-helix. Strongly kinked β2,3 is essential for domain-domain interactions between head domain, dorsal fin domain, right flipper domain, and loop β7,8 in P2X4 receptors. Disulfide cross-linking with directions opposing or along the bending angle of the β2,3-sheet toward the α2-helix led to loss-of-function and gain-of-function of P2X4 receptors, respectively. Further insertion of amino acids with bulky side chains into the linker between the β2,3-sheet or the conformational change of the α2-helix, interfering with the kinked conformation of β2,3, led to loss-of-function of P2X4 receptors. All these findings provided new insights in understanding the contribution of the salt bridge between Asp-85 and Arg-309 and its structurally coupled β2,3-sheet to the function of P2X receptors. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Towards a robust assessment of bridge clogging processes in flood risk management

    NASA Astrophysics Data System (ADS)

    Gschnitzer, T.; Gems, B.; Mazzorana, B.; Aufleger, M.

    2017-02-01

    River managers are aware that wood-clogging mechanisms frequently trigger damage-causing processes like structural damages at bridges, sudden channel outbursts, and occasionally, major displacements of the water course. To successfully mitigate flood risks related to the transport of large wood (LW), river managers need a guideline for an accurate and reliable risk assessment procedure and the design of river sections and bridges that are endangered of LW clogging. In recent years, comprehensive research dealing with the triggers of wood-clogging mechanisms at bridges and the corresponding impacts on flood risk was accomplished at the University of Innsbruck. A large set of laboratory experiments in a rectangular flume was conducted. In this paper we provide an overall view of these tests and present our findings. By applying a logistic regression analysis, the available knowledge on the influence of geometrical, hydraulic, and wood-related parameters on LW clogging probabilities is processed in a generalized form. Based on the experimental modeling results a practice-oriented guideline that supports the assessment of flood risk induced by LW clogging, is presented. In this context, two specific local structural protection measures at the bridge, aiming for a significant decrease of the entrapment probabilities, are illustrated: (i) a deflecting baffle installed on the upstream face of the bridge and (ii) a channel constriction leading to a change in flow state and a corresponding increase of the flow velocities and the freeboard at the bridge cross section. The presented guideline is based on a three-step approach: estimation of LW potential, entrainment, and transport; clogging scenario at the bridge; and the impact on channel and floodplain hydraulics. For a specific bridge susceptible to potential clogging caused by LW entrapment, it allows for a qualitative evaluation of potential LW entrainment in the upstream river segments, its transport toward the hydraulic bottleneck, and for a quantification of expected entrapment probabilities. Depending on the amount and characteristics of the impacting LW, consequences of bridge clogging can be determined and LW bridge-clogging scenarios can be considered within hydrodynamic numerical modeling.

  12. 11. Photocopy of drawing (this photograph is an 8''x 10''contact ...

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

    11. Photocopy of drawing (this photograph is an 8''x 10''contact print; February 7, 1989 revision of a September, 1986 as built drawing by D. Monclova, in possession of the Highway Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Santiago (sic) Channel, Route no. 2 km. 75.50, Arecibo, P.R. Bridge no. 53. No. 1 of 2. - Puente del Cano Carate, Spanning Cano Carate Channel, Arecibo, Arecibo Municipio, PR

  13. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  14. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  15. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  16. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  17. 33 CFR 117.721 - Grassy Sound Channel.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Grassy Sound Channel. 117.721... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.721 Grassy Sound Channel. The draw of the Grassy Sound Channel Bridge, mile 1.0 in Middle Township, shall open on signal from 6 a.m. to 8 p...

  18. Geomorphology and river dynamics of the lower Copper River, Alaska

    USGS Publications Warehouse

    Brabets, Timothy P.; Conaway, Jeffrey S.

    2009-01-01

    Located in south-central Alaska, the Copper River drains an area of more than 24,000 square miles. The average annual flow of the river near its mouth is 63,600 cubic feet per second, but is highly variable between winter and summer. In the winter, flow averages approximately 11,700 cubic feet per second, and in the summer, due to snowmelt, rainfall, and glacial melt, flow averages approximately 113,000 cubic feet per second, an order of magnitude higher. About 15 miles upstream of its mouth, the Copper River flows past the face of Childs Glacier and enters a large, broad, delta. The Copper River Highway traverses this flood plain, and in 2008, 11 bridges were located along this section of the highway. The bridges cross several parts of the Copper River and in recent years, the changing course of the river has seriously damaged some of the bridges.Analysis of aerial photography from 1991, 1996, 2002, 2006, and 2007 indicates the eastward migration of a channel of the Copper River that has resulted in damage to the Copper River Highway near Mile 43.5. Migration of another channel in the flood plain has resulted in damage to the approach of Bridge 339. As a verification of channel change, flow measurements were made at bridges along the Copper River Highway in 2005–07. Analysis of the flow measurements indicate that the total flow of the Copper River has shifted from approximately 50 percent passing through the bridges at Mile 27, near the western edge of the flood plain, and 50 percent passing through the bridges at Mile 36–37 to approximately 5 percent passing through the bridges at Mile 27 and 95 percent through the bridges at Mile 36–37 during average flow periods.The U.S. Geological Survey’s Multi-Dimensional Surface-Water Modeling System was used to simulate water-surface elevation and velocity, and to compute bed shear stress at two areas where the Copper River is affecting the Copper River Highway. After calibration, the model was used to examine the effects that betterments, such as guide banks or bridge extensions, would have on flow conditions and to provide sound conceptual information that could help decide if a proposed betterment will work or determine potential problems that need to be addressed for a particular betterment. The ability of the model to simulate these hydraulic conditions was constrained by the accuracy and level of channel geometry detail, which is constantly changing in the lower Copper River.

  19. 33 CFR 118.75 - Lights on single-opening drawbridges.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... span. (c) Pier or abutment lights. Every swing bridge shall be lighted so that the end of each pier, abutment or fixed portion of the bridge adjacent to the navigable channel through the draw, or each end of the protection piers for such piers, abutments, or fixed portion of the bridge will be marked by a red...

  20. 33 CFR 117.225 - Yellow Mill Channel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Yellow Mill Channel. 117.225 Section 117.225 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Connecticut § 117.225 Yellow Mill Channel. The...

  1. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  2. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  3. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  4. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  5. 33 CFR 117.598 - Eel Pond Channel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Eel Pond Channel. 117.598 Section 117.598 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.598 Eel Pond Channel. The...

  6. Insights from depth-averaged numerical simulation of flow at bridge abutments in compound channels.

    DOT National Transportation Integrated Search

    2011-07-01

    Two-dimensional, depth-averaged flow models are used to study the distribution of flow around spill-through abutments situated on floodplains in compound channels and rectangular channels (flow on very wide floodplains may be treated as rectangular c...

  7. Real-Time River Channel-Bed Monitoring at the Chariton and Mississippi Rivers in Missouri, 2007-09

    USGS Publications Warehouse

    Rydlund, Jr., Paul H.

    2009-01-01

    Scour and depositional responses to hydrologic events have been important to the scientific community studying sediment transport as well as potential effects on bridges and other hydraulic structures within riverine systems. A river channel-bed monitor composed of a single-beam transducer was installed on a bridge crossing the Chariton River near Prairie Hill, Missouri (structure L-344) as a pilot study to evaluate channel-bed change in response to the hydrologic condition disseminated from an existing streamgage. Initial results at this location led to additional installations in cooperation with the Missouri Department of Transportation at an upstream Chariton River streamgage location at Novinger, Missouri (structure L-534) and a Mississippi River streamgage location near Mehlville, Missouri (structures A-1850 and A-4936). In addition to stage, channel-bed elevation was collected at all locations every 15 minutes and transmitted hourly to a U.S. Geological Survey database. Bed elevation data for the Chariton River location at Novinger and the Mississippi River location near Mehlville were provided to the World Wide Web for real-time monitoring. Channel-bed data from the three locations indicated responses to hydrologic events depicted in the stage record; however, notable bedforms apparent during inter-event flows also may have affected the relation of scour and deposition to known hydrologic events. Throughout data collection periods, Chariton River locations near Prairie Hill and Novinger reflected bed changes as much as 13 feet and 5 feet. Nearly all of the bed changes correlated well with the hydrographic record at these locations. The location at the Mississippi River near Mehlville indicated a much more stable channel bed throughout the data collection period. Despite missing data resulting from damage to one of the river channel-bed monitors from ice accumulation at the upstream nose of the bridge pier early in the record, the record from the downstream river channel-bed monitor demonstrated a good correlation (regardless of a 7 percent high bias) between bedform movement and the presence of bedforms surrounding the bridge as indicated by coincident bathymetric surveys using multibeam sonar.

  8. 37. View of the control house on the north tower ...

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

    37. View of the control house on the north tower from the north span facing north. Note mirror and video camera used by bridge operator to check for vessel traffic prior to operating the bridge, loudspeaker and sirens to warn pedestrians and boaters. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  9. Rapid multichannel impact-echo scanning of concrete bridge decks from a continuously moving platform

    NASA Astrophysics Data System (ADS)

    Mazzeo, Brian A.; Larsen, Jacob; McElderry, Joseph; Guthrie, W. Spencer

    2017-02-01

    Impact-echo testing is a non-destructive evaluation technique for determining the presence of defects in reinforced concrete bridge decks based on the acoustic response of the bridge deck when struck by an impactor. In this work, we build on our prior research with a single-channel impactor to demonstrate a seven-channel impact-echo scanning system with independent control of the impactors. This system is towed by a vehicle and integrated with distance measurement for registering the locations of the impacts along a bridge deck. The entire impact and recording system is computer-controlled. Because of a winch system and hinged frame construction of the apparatus, setup, measurement, and take-down of the apparatus can be achieved in a matter of minutes. Signal processing of the impact responses is performed on site and can produce a map of delaminations immediately after data acquisition. This map can then be used to guide other testing and/or can be referenced with the results of other testing techniques to facilitate comprehensive condition assessments of concrete bridge decks. This work demonstrates how impact-echo testing can be performed in a manner that makes complete bridge deck scanning for delaminations rapid and practical.

  10. Risk analysis of emergent water pollution accidents based on a Bayesian Network.

    PubMed

    Tang, Caihong; Yi, Yujun; Yang, Zhifeng; Sun, Jie

    2016-01-01

    To guarantee the security of water quality in water transfer channels, especially in open channels, analysis of potential emergent pollution sources in the water transfer process is critical. It is also indispensable for forewarnings and protection from emergent pollution accidents. Bridges above open channels with large amounts of truck traffic are the main locations where emergent accidents could occur. A Bayesian Network model, which consists of six root nodes and three middle layer nodes, was developed in this paper, and was employed to identify the possibility of potential pollution risk. Dianbei Bridge is reviewed as a typical bridge on an open channel of the Middle Route of the South to North Water Transfer Project where emergent traffic accidents could occur. Risk of water pollutions caused by leakage of pollutants into water is focused in this study. The risk for potential traffic accidents at the Dianbei Bridge implies a risk for water pollution in the canal. Based on survey data, statistical analysis, and domain specialist knowledge, a Bayesian Network model was established. The human factor of emergent accidents has been considered in this model. Additionally, this model has been employed to describe the probability of accidents and the risk level. The sensitive reasons for pollution accidents have been deduced. The case has also been simulated that sensitive factors are in a state of most likely to lead to accidents. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. 78 FR 26508 - Drawbridge Operation Regulations; Reynolds Channel, Nassau, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-07

    ... Regulations; Reynolds Channel, Nassau, NY AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from... regulation governing the operation of the Long Beach Bridge, mile 4.7, across Reynolds Channel at Nassau, New.... on July 12, 2013. Reynolds Creek has commercial and recreational vessel traffic. No objections were...

  12. 78 FR 37456 - Drawbridge Operation Regulations; Reynolds Channel, Nassau, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-21

    ... Regulations; Reynolds Channel, Nassau, NY AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from... regulation governing the operation of the Long Beach Bridge, mile 4.7, across Reynolds Channel at Nassau, New... July 1, 2013. Reynolds Creek has commercial and recreational vessel traffic. No objections were...

  13. 14. DETAIL VIEW OF SERVICE BRIDGE, SHOWING TRAVELLING CRANE AND ...

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

    14. DETAIL VIEW OF SERVICE BRIDGE, SHOWING TRAVELLING CRANE AND TAINTER GATE PIER WITH RECESSES FOR EMERGENCY BULKHEADS AND BULKHEAD DOGGING DEVICES, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  14. View of movable span and point truss (to right), from ...

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

    View of movable span and point truss (to right), from navy land, looking west, showing bridge in context of navigational channel. - Naval Supply Annex Stockton, Daggett Road Bridge, Daggett Road traversing Burns Cut Off, Stockton, San Joaquin County, CA

  15. 21. VIEW OF MIANUS RIVER RAILROAD BRIDGE LOOKING NORTHEAST FROM ...

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

    21. VIEW OF MIANUS RIVER RAILROAD BRIDGE LOOKING NORTHEAST FROM THE REMAINS OF THE COS COB POWER PLANT COALING DOCK. THE BRIDGE IS A ROLLING LIFT BASCULE TYPE BUILT IN 1894-1895. NOTE THE ABSENCE OF CATENARY OVER THE CHANNEL AND THE METHOD OF CARRYING POWER FEED OVER THE RIVER ON THE HIGH TOWERS ADJACENT TO THE LIFT SECTION OF THE BRIDGE. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  16. Procedures for scour assessments at bridges in Pennsylvania

    USGS Publications Warehouse

    Cinotto, Peter J.; White, Kirk E.

    2000-01-01

    Scour is the process and result of flowing water eroding the bed and banks of a stream. Scour at nearly 14,300 bridges(1) spanning water, and the stability of river and stream channels in Pennsylvania, are being assessed by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Transportation (PennDOT). Procedures for bridge-scour assessments have been established to address the needs of PennDOT in meeting a 1988 Federal Highway Administration mandate requiring states to establish a program to assess all public bridges over water for their vulnerability to scour. The procedures also have been established to help develop an understanding of the local and regional factors that affect scour and channel stability. This report describes procedures for the assessment of scour at all bridges that are 20 feet or greater in length that span water in Pennsylvania. There are two basic types of assessment: field-viewed bridge site assessments, for which USGS personnel visit the bridge site, and office-reviewed bridge site assessments, for which USGS personnel compile PennDOT data and do not visit the bridge site. Both types of assessments are primarily focused at assisting PennDOT in meeting the requirements of the Federal Highway Administration mandate; however, both assessments include procedures for the collection and processing of ancillary data for subsequent analysis. Date of bridge construction and the accessibility of the bridge substructure units for inspection determine which type of assessment a bridge receives. A Scour-Critical Bridge Indicator Code and a Scour Assessment Rating are computed from selected collected and compiled data. PennDOT personnel assign the final Scour-Critical Bridge Indicator Code and a Scour Assessment Rating on the basis of their review of all data. (1)Words presented in bold type are defined in the Glossary section of this report.

  17. A large iris-like expansion of a mechanosensitive channel protein induced by membrane tension

    NASA Technical Reports Server (NTRS)

    Betanzos, Monica; Chiang, Chien-Sung; Guy, H. Robert; Sukharev, Sergei

    2002-01-01

    MscL, a bacterial mechanosensitive channel of large conductance, is the first structurally characterized mechanosensor protein. Molecular models of its gating mechanisms are tested here. Disulfide crosslinking shows that M1 transmembrane alpha-helices in MscL of resting Escherichia coli are arranged similarly to those in the crystal structure of MscL from Mycobacterium tuberculosis. An expanded conformation was trapped in osmotically shocked cells by the specific bridging between Cys 20 and Cys 36 of adjacent M1 helices. These bridges stabilized the open channel. Disulfide bonds engineered between the M1 and M2 helices of adjacent subunits (Cys 32-Cys 81) do not prevent channel gating. These findings support gating models in which interactions between M1 and M2 of adjacent subunits remain unaltered while their tilts simultaneously increase. The MscL barrel, therefore, undergoes a large concerted iris-like expansion and flattening when perturbed by membrane tension.

  18. Channel stability of Turkey Creek, Nebraska

    USGS Publications Warehouse

    Rus, David L.; Soenksen, Philip J.

    1998-01-01

    Channelization on Turkey Creek and its receiving stream, the South Fork Big Nemaha River, has disturbed the equilibrium of Turkey Creek and has led to channel-stability problems, such as degradation and channel widening, which pose a threat to bridges and land adjacent to the stream. As part of a multiagency study, the U.S. Geological Survey assessed channel stability at two bridge sites on upper and middle portions of Turkey Creek by analyzing streambed-elevation data for gradation changes, comparing recent cross-section surveys and historic accounts, identifying bank-failure blocks, and analyzing tree-ring samples. These results were compared to gradation data and trend results for a U.S. Geological Survey streamflow-gaging station near the mouth of Turkey Creek from a previous study. Examination of data on streambed elevations reveals that degradation has occurred. The streambed elevation declined 0.5 m at the upper site from 1967-97. The streambed elevation declined by 3.2 m at the middle site from 1948-97 and exposed 2 m of the pilings of the Nebraska Highway 8 bridge. Channel widening could not be verified at the two sites from 1967-97, but a historic account indicates widening at the middle site to be two to three times that of the 1949 channel width. Small bank failures were evident at the upper site and a 4-m-wide bank failure occurred at the middle site in 1987 according to tree ring analyses. Examination of streambed-elevation data from a previous study at the lower site reveals a statistically significant aggrading trend from 1958-93. Further examination of these data suggests minor degradation occurred until 1975, followed by aggradation.

  19. Bathymetric surveys at highway bridges crossing the Missouri River in Kansas City, Missouri, using a multibeam echo sounder, 2010

    USGS Publications Warehouse

    Huizinga, Richard J.

    2010-01-01

    Bathymetric surveys were conducted by the U.S. Geological Survey, in cooperation with the Missouri Department of Transportation, on the Missouri River in the vicinity of nine bridges at seven highway crossings in Kansas City, Missouri, in March 2010. A multibeam echo sounder mapping system was used to obtain channel-bed elevations for river reaches that ranged from 1,640 to 1,800 feet long and extending from bank to bank in the main channel of the Missouri River. These bathymetric scans will be used by the Missouri Department of Transportation to assess the condition of the bridges for stability and integrity with respect to bridge scour. Bathymetric data were collected around every pier that was in water, except those at the edge of the water or in extremely shallow water, and one pier that was surrounded by a large debris raft. A scour hole was present at every pier for which bathymetric data could be obtained. The scour hole at a given pier varied in depth relative to the upstream channel bed, depending on the presence and proximity of other piers or structures upstream from the pier in question. The surveyed channel bed at the bottom of the scour hole was between 5 and 50 feet above bedrock. At bridges with drilled shaft foundations, generally there was exposure of the upstream end of the seal course and the seal course often was undermined to some extent. At one site, the minimum elevation of the scour hole at the main channel pier was about 10 feet below the bottom of the seal course, and the sides of the drilled shafts were evident in a point cloud visualization of the data at that pier. However, drilled shafts generally penetrated 20 feet into bedrock. Undermining of the seal course was evident as a sonic 'shadow' in the point cloud visualization of several of the piers. Large dune features were present in the channel at nearly all of the surveyed sites, as were numerous smaller dunes and many ripples. Several of the sites are on or near bends in the river, resulting in a deep channel thalweg on the outside of the bend at these sites. At structure A5817 on State Highway 269, bedrock exposure was evident in the channel thalweg. The surveyed channel bed at a given site from this study generally was lower than the channel bed obtained during Level II scour assessments in 2002. At piers with well-defined scour holes, the frontal slopes of the holes were somewhat less than recommended values in the literature, and the shape of the holes appeared to be affected by the movement of dune features into and around the holes. The channel bed at all of the surveyed sites was lower than the channel bed at the time of construction, and an analysis of measurement data from the U.S. Geological Survey continuous streamflow-gaging station on the Missouri River at Kansas City, Missouri (station number 06893000), confirmed a lowering trend of the channel-bed elevations with time at the gaging station. The size of the scour holes observed at the surveyed sites likely was affected by the moderate flood conditions on the Missouri River at the time of the surveys. The scour holes likely would be substantially smaller during conditions of low flow.

  20. 33 CFR 117.753 - Ship Channel, Great Egg Harbor Bay.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Ship Channel, Great Egg Harbor Bay. 117.753 Section 117.753 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND..., Great Egg Harbor Bay. The draw of the S52 (Ship Channel) bridge, mile 0.5 between Somers Point and Ocean...

  1. 33 CFR 117.753 - Ship Channel, Great Egg Harbor Bay.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Ship Channel, Great Egg Harbor Bay. 117.753 Section 117.753 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND..., Great Egg Harbor Bay. The draw of the S52 (Ship Channel) bridge, mile 0.5 between Somers Point and Ocean...

  2. Split-cross-bridge resistor for testing for proper fabrication of integrated circuits

    NASA Technical Reports Server (NTRS)

    Buehler, M. G. (Inventor)

    1985-01-01

    An electrical testing structure and method is described whereby a test structure is fabricated on a large scale integrated circuit wafer along with the circuit components and has a van der Pauw cross resistor in conjunction with a bridge resistor and a split bridge resistor, the latter having two channels each a line width wide, corresponding to the line width of the wafer circuit components, and with the two channels separated by a space equal to the line spacing of the wafer circuit components. The testing structure has associated voltage and current contact pads arranged in a two by four array for conveniently passing currents through the test structure and measuring voltages at appropriate points to calculate the sheet resistance, line width, line spacing, and line pitch of the circuit components on the wafer electrically.

  3. Assessing Stream Channel Stability at Bridges in Physiographic Regions

    DOT National Transportation Integrated Search

    2006-07-01

    The objective of this study was to expand and improve a rapid channel stability assessment method developed previously by Johnson et al. to include additional factors, such as major physiographic units across the United States, a greater range of ban...

  4. 14. VIEW OF ARROYO SECO CHANNEL AND INTERSTATE I5 OVERCROSSING ...

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

    14. VIEW OF ARROYO SECO CHANNEL AND INTERSTATE I-5 OVERCROSSING SEEN FROM SAN FERNANDO ROAD BRIDGE. LOOKING 10°N. - Arroyo Seco Parkway, Figueroa Street Viaduct, Spanning Los Angeles River, Los Angeles, Los Angeles County, CA

  5. 12. VIEW OF ARROYO SECO CHANNEL SEEN FROM SAN FERNANDO ...

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

    12. VIEW OF ARROYO SECO CHANNEL SEEN FROM SAN FERNANDO BRIDGE. NOTE VIADUCTS AND TUNNEL PORTAL AT REAR. LOOKING 234°SW. - Arroyo Seco Parkway, Figueroa Street Viaduct, Spanning Los Angeles River, Los Angeles, Los Angeles County, CA

  6. Detail of diagonal end post support bracket mounted to east ...

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

    Detail of diagonal end post support bracket mounted to east face of track girder, east span. View south - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  7. 33 CFR 117.253 - Anacostia River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... open position for vessel traffic. During open span movement, the channel traffic lights will flash red... traffic lights will flash red, and an audio voice-warning device will announce bridge movement during... will continue to flash red. (6) The owners of the bridge shall provide and keep in good legible...

  8. 33 CFR 117.253 - Anacostia River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... open position for vessel traffic. During open span movement, the channel traffic lights will flash red... traffic lights will flash red, and an audio voice-warning device will announce bridge movement during... will continue to flash red. (6) The owners of the bridge shall provide and keep in good legible...

  9. 33 CFR 117.253 - Anacostia River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... open position for vessel traffic. During open span movement, the channel traffic lights will flash red... traffic lights will flash red, and an audio voice-warning device will announce bridge movement during... will continue to flash red. (6) The owners of the bridge shall provide and keep in good legible...

  10. Channel bed degradation in major Oklahoma streams volume IV of V : Canadian River.

    DOT National Transportation Integrated Search

    2007-12-01

    The purpose of this research is to analyze the flowline data and relate it to the degradation of the : river bed at bridge locations in the river. This information may then be used to replace or rehabilitate those : bridges that experienced severe de...

  11. Channel bed degradation in major Oklahoma streams volume III of IV North Canadian River.

    DOT National Transportation Integrated Search

    2007-12-01

    The purpose of this research is to analyze the flowline data and relate it to the degradation of the river bed at bridge locations in the river. This information may then be used to replace or rehabilitate those bridges that experienced severe degrad...

  12. Channel bed degradation in major Oklahoma Streams volume I of IV : Arkansas River.

    DOT National Transportation Integrated Search

    2007-12-01

    The purpose of this research is to analyze the flowline data and relate it to the degradation of the : river bed at bridge locations in the river. This information may then be used to replace or rehabilitate : those bridges that experienced severe de...

  13. Channel bed degradation in major Oklahoma streams volume V of V : Washita River.

    DOT National Transportation Integrated Search

    2007-12-01

    The purpose of this research is to analyze the flowline data and relate it to the degradation of the river : bed at bridge locations in the river. This information may then be used to replace or rehabilitate those : bridges that experienced severe de...

  14. 77 FR 22492 - Drawbridge Operation Regulations; Long Island, New York Inland Waterway from East Rockaway Inlet...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-16

    ... operation of the Atlantic Beach Bridge, mile 0.4, across Reynolds Channel at Lawrence, New York. The owner... marine transportation system that transit Reynolds Channel. Under 5 U.S.C. 553(d)(3), the Coast Guard..., across Reynolds Channel at Lawrence, New York, has a vertical clearance in the closed position of 25 feet...

  15. Level II scour analysis for Bridge 6 (MORRTH00030006) on Town Highway 3, crossing Ryder Brook, Morristown, Vermont

    USGS Publications Warehouse

    Boehmler, Erick M.; Hammond, Robert E.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure MORRTH00030006 on Town Highway 3 crossing Ryder Brook, Morristown, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in north-central Vermont. The 19.1-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover also is forested. In the study area, Ryder Brook has a straight channel with an average channel top width of 450 ft and an average bank height of 7 ft. The predominant channel bed material is silt and clay with a median grain size (D50) of 0.0719 mm (0.000236 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 18, 1996, indicated that the reach was aggraded, but the channel through the bridge was scoured. The Town Highway 3 crossing of Ryder Brook is a 72-ft-long, two-lane bridge consisting of one 70-foot steel-beam span (Vermont Agency of Transportation, written communication, January 31, 1996). The bridge is supported by vertical, concrete abutments with spill-through embankments and wingwalls. The channel is not skewed to the opening and the opening-skew-to-roadway is zero degrees. Channel scour under the bridge was evident at this site during the Level I assessment. The depth of the channel increases from 3 feet at the upstream bridge face to 10 feet at the downstream bridge face. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) on the spill-through embankments of each abutment, the upstream road embankments and the downstream left road embankment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 20.4 to 25.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 8.3 to 10.5 ft. The worst-case abutment scour also occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  16. Use of GDNF Releasing Nanofiber Nerve Guide Conduits for the Repair of Conus Medullaris/Cauda Equina Injury in the Nonhuman Primate

    DTIC Science & Technology

    2015-02-01

    repair of conus medullaris/cauda equina injury in rhesus macaques using a biodegradable bridging graft that releasing the trophic factor, GDNF. All...and biodegradable nerve guidance channels as bridging grafts. The follow section describes the methods and protocols for laminectomy, ventral root...in saline until being grafted, 8. For use of a bridging biodegradable NGC segment, the NGCs were fabricated and comprised of electrospun

  17. Level II scour analysis for Bridge 42 (RANDVT00120042) on State Highway 12, crossing Third Branch White River, Randolph, Vermont

    USGS Publications Warehouse

    Olson, Scott A.; Weber, Matthew A.

    1996-01-01

    bridge consisting of four concrete spans. The maximum span length is 57 ft. (Vermont Agency of Transportation, written commun., July 29, 1994). The bridge is supported by vertical, concrete abutments and three concrete piers. The toe of the left abutment is at the channel edge. The toe of the right abutment is set back on the right over-bank. The roadway centerline on the structure has a slight horizontal curve; however, the main channel is skewed approximately 5 degrees to the bridge. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

  18. Research to support design and siting of deposition areas for dredged material from the Rodanthe Emergency Channel

    DOT National Transportation Integrated Search

    2017-06-30

    The Rodanthe Emergency Ferry Channel (REFC) is essential for transporting emergency personnel, equipment, and supplies to Hatteras Island communities following any event that renders the Herbert C. Bonner Bridge and/or North Carolina Highway 12 impas...

  19. 26. Detail of south granite pier revealing riveted truss ends ...

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

    26. Detail of south granite pier revealing riveted truss ends and iron footing plates on top of granite cap stones. View north - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  20. 33 CFR 117.822 - Beaufort Channel, NC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements North Carolina § 117.822 Beaufort Channel, NC. The... bridge need not open between the hours of 6:30 a.m. to 8 a.m. and 4:30 p.m. to 6 p.m. (b) From 10 p.m. to...

  1. 40. Detail of typical subdeck of granite pier showing humanscale ...

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

    40. Detail of typical subdeck of granite pier showing human-scale arched openings in pies. Note remnants of fender system. View north - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  2. Reciprocal voltage sensor-to-pore coupling leads to potassium channel C-type inactivation

    PubMed Central

    Conti, Luca; Renhorn, Jakob; Gabrielsson, Anders; Turesson, Fredrik; Liin, Sara I; Lindahl, Erik; Elinder, Fredrik

    2016-01-01

    Voltage-gated potassium channels open at depolarized membrane voltages. A prolonged depolarization causes a rearrangement of the selectivity filter which terminates the conduction of ions – a process called slow or C-type inactivation. How structural rearrangements in the voltage-sensor domain (VSD) cause alteration in the selectivity filter, and vice versa, are not fully understood. We show that pulling the pore domain of the Shaker potassium channel towards the VSD by a Cd2+ bridge accelerates C-type inactivation. Molecular dynamics simulations show that such pulling widens the selectivity filter and disrupts the K+ coordination, a hallmark for C-type inactivation. An engineered Cd2+ bridge within the VSD also affect C-type inactivation. Conversely, a pore domain mutation affects VSD gating-charge movement. Finally, C-type inactivation is caused by the concerted action of distant amino acid residues in the pore domain. All together, these data suggest a reciprocal communication between the pore domain and the VSD in the extracellular portion of the channel. PMID:27278891

  3. Reciprocal voltage sensor-to-pore coupling leads to potassium channel C-type inactivation

    NASA Astrophysics Data System (ADS)

    Conti, Luca; Renhorn, Jakob; Gabrielsson, Anders; Turesson, Fredrik; Liin, Sara I.; Lindahl, Erik; Elinder, Fredrik

    2016-06-01

    Voltage-gated potassium channels open at depolarized membrane voltages. A prolonged depolarization causes a rearrangement of the selectivity filter which terminates the conduction of ions - a process called slow or C-type inactivation. How structural rearrangements in the voltage-sensor domain (VSD) cause alteration in the selectivity filter, and vice versa, are not fully understood. We show that pulling the pore domain of the Shaker potassium channel towards the VSD by a Cd2+ bridge accelerates C-type inactivation. Molecular dynamics simulations show that such pulling widens the selectivity filter and disrupts the K+ coordination, a hallmark for C-type inactivation. An engineered Cd2+ bridge within the VSD also affect C-type inactivation. Conversely, a pore domain mutation affects VSD gating-charge movement. Finally, C-type inactivation is caused by the concerted action of distant amino acid residues in the pore domain. All together, these data suggest a reciprocal communication between the pore domain and the VSD in the extracellular portion of the channel.

  4. Bathymetric and velocimetric surveys at highway bridges crossing the Missouri River in and into Missouri during summer flooding, July-August 2011

    USGS Publications Warehouse

    Huizinga, Richard J.

    2012-01-01

    Bathymetric and velocimetric surveys were conducted by the U.S. Geological Survey, in cooperation with the Kansas and Missouri Departments of Transportation, in the vicinity of 36 bridges at 27 highway crossings of the Missouri River between Brownville, Nebraska and St. Louis, Missouri, from July 13 through August 3, 2011, during a summer flood. A multibeam echo sounder mapping system was used to obtain channel-bed elevations for river reaches ranging from 1,350 to 1,860 feet and extending across the active channel of the Missouri River. These bathymetric scans provide a "snapshot" of the channel conditions at the time of the surveys and provide characteristics of scour holes that may be useful in the development of predictive guidelines or equations for scour holes. These data also may be used by the Kansas and Missouri Departments of Transportation to assess the bridges for stability and integrity issues with respect to bridge scour during floods. Bathymetric data were collected around every pier that was in water, except those at the edge of water, in extremely shallow water, or surrounded by debris rafts. Scour holes were present at most piers for which bathymetry could be obtained, except at piers on channel banks, those near or embedded in lateral or longitudinal spur dikes, and those on exposed bedrock outcrops. Scour holes observed at the surveyed bridges were examined with respect to depth and shape. Although exposure of parts of foundational support elements was observed at several piers, at most sites the exposure likely can be considered minimal compared to the overall substructure that remains buried in bed material; however, there were several notable exceptions where the bed material thickness between the bottom of the scour hole and bedrock was less than 6 feet. Such substantial exposure of usually buried substructural elements may warrant special observation in future flood events. Previous bathymetric surveys had been done at several of the sites, and comparisons between bathymetric surfaces from the previous surveys and those of this study indicate substantial variability in the response of the channel bed to the 2011 summer flood conditions. At sites in Kansas City, there was no consistent deepening of the channel or increase in the size of scour holes, despite substantially more discharge and a higher water-surface elevation in the 2011 surveys, which implies the high-flow conditions during the 2011 surveys created a similar scour scenario to the previous surveys. At Jefferson City and the St. Louis sites, there was a consistent deepening of the channel, and a slight to substantial increase in the depth of scour holes in the 2011 surveys compared to previous surveys, although the effects of the higher flow appeared to be mitigated by the shape and alignment of the piers at most sites in St. Louis. Construction activities related to a new bridge at the Atchison, Kansas, site likely have contributed to the substantial additional scour observed there in a previous survey during the 2010 flooding, and the subsequent aggradation of the channel bed observed in the 2011 survey. Pier size, nose shape, and alignment to flow also had a profound effect on the size of the scour hole observed for a given pier.

  5. 39. View of bridge operators controls in the control house ...

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

    39. View of bridge operators controls in the control house facing south. Controls on the right are for the south span and on the left for the north span. The large dial indicator towards the top of the picture is a position indicator for the south span. Also present is a marine radio for talking to marine traffic and control ropes for the horn and siren. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  6. Design and performance of self-consolidating concrete for connecting precast concrete deck panels and bridge I-girders.

    DOT National Transportation Integrated Search

    2014-08-01

    Existing full-depth precast concrete deck systems use either open channels or pockets to accommodate the shear connectors of supporting girders for achieving composite systems. The use of open channels or pockets requires cast-in-place concrete/grout...

  7. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  8. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  9. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  10. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  11. 33 CFR 117.751 - Shark River (South Channel).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  12. Disruption of Alluvial Fan Processes in a Cascade Range Stream, and Attempts to Address the Resulting Problems...

    NASA Astrophysics Data System (ADS)

    DeVries, P.

    2016-12-01

    Alluvial fan processes have been altered in two ways on Mouse Creek, tributary of the Sauk River, WA. A county road and low profile bridge were built in the vicinity of a large scale break in slope, and a berm was built upstream along one bank to confine flows. The system has a high sediment load from episodic mass wasting upstream. Over 10 years of survey data and analyses provide a case study of aggradation, flooding, and avulsion processes above the road crossing, and of efforts to address the resulting problems. The berm precluded fan deposition upstream, and appears to have shifted the deposition zone downstream closer to the bridge, leading to an avulsion and impacting upstream migration of salmon to spawning habitat. In addition, the bed elevation of the channel is now higher than the historic fan surface on the other side of the berm. The bridge was raised to reduce the road crossing influence on sediment transport and deposition, which worked for a while locally until the avulsion developed, which accelerated aggradation in the former main channel above the bridge. Plans have been developed for removing the berm and allowing the stream to re-engage its fan. The key design question presently is: should the berm be excavated to its toe on the channel side to accelerate restoration of depositional processes, or should a semblance of bankfull morphology be retained?

  13. Simultaneous Observations of p-mode Light Walls and Magnetic Reconnection Ejections above Sunspot Light Bridges

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hou, Yijun; Zhang, Jun; Li, Ting

    Recent high-resolution observations from the Interface Region Imaging Spectrograph reveal bright wall-shaped structures in active regions (ARs), especially above sunspot light bridges. Their most prominent feature is the bright oscillating front in the 1400/1330 Å channel. These structures are named light walls and are often interpreted to be driven by p-mode waves. Above the light bridge of AR 12222 on 2014 December 06, we observed intermittent ejections superimposed on an oscillating light wall in the 1400 Å passband. At the base location of each ejection, the emission enhancement was detected in the Solar Dynamics Observatory 1600 Å channel. Thus, wemore » suggest that in wall bases (light bridges), in addition to the leaked p-mode waves consistently driving the oscillating light wall, magnetic reconnection could happen intermittently at some locations and eject the heated plasma upward. Similarly, in the second event occurring in AR 12371 on 2015 June 16, a jet was simultaneously detected in addition to the light wall with a wave-shaped bright front above the light bridge. At the footpoint of this jet, lasting brightening was observed, implying magnetic reconnection at the base. We propose that in these events, two mechanisms, p-mode waves and magnetic reconnection, simultaneously play roles in the light bridge, and lead to the distinct kinetic features of the light walls and the ejection-like activities, respectively. To illustrate the two mechanisms and their resulting activities above light bridges, in this study we present a cartoon model.« less

  14. 3. DOWNSTREAM AERIAL VIEW OF THE DIVERSION CHANNEL AND CONTROL ...

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

    3. DOWNSTREAM AERIAL VIEW OF THE DIVERSION CHANNEL AND CONTROL WORKS. THE OUTLET CONTROL TOWER AND THE PIER FOR THE SERVICE BRIDGE ARE SHOWN COMPLETED.... Volume XVIII, No. 11, January 18, 1940. - Prado Dam, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  15. Ground-penetrating radar: A tool for monitoring bridge scour

    USGS Publications Warehouse

    Anderson, N.L.; Ismael, A.M.; Thitimakorn, T.

    2007-01-01

    Ground-penetrating radar (GPR) data were acquired across shallow streams and/or drainage ditches at 10 bridge sites in Missouri by maneuvering the antennae across the surface of the water and riverbank from the bridge deck, manually or by boat. The acquired two-dimensional and three-dimensional data sets accurately image the channel bottom, demonstrating that the GPR tool can be used to estimate and/or monitor water depths in shallow fluvial environments. The study results demonstrate that the GPR tool is a safe and effective tool for measuring and/or monitoring scour in proximity to bridges. The technique can be used to safely monitor scour at assigned time intervals during peak flood stages, thereby enabling owners to take preventative action prior to potential failure. The GPR tool can also be used to investigate depositional and erosional patterns over time, thereby elucidating these processes on a local scale. In certain instances, in-filled scour features can also be imaged and mapped. This information may be critically important to those engaged in bridge design. GPR has advantages over other tools commonly employed for monitoring bridge scour (reflection seismic profiling, echo sounding, and electrical conductivity probing). The tool doesn't need to be coupled to the water, can be moved rapidly across (or above) the surface of a stream, and provides an accurate depth-structure model of the channel bottom and subchannel bottom sediments. The GPR profiles can be extended across emerged sand bars or onto the shore.

  16. Health monitoring of Binzhou Yellow River highway bridge using fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Ou, Jinping; Zhao, Xuefeng; Li, Hui; Zhou, Zhi; Zhang, Zhichun; Wang, Chuan

    2005-05-01

    Binzhou yellow river Highway Bridge with 300 meter span and 768 meter length is located in the Shandong province of China and is the first cable stayed bridge with three towers along the yellow river, one of the biggest rivers in China. In order to monitoring the strain and temperature of the bridge and evaluate the health condition, one fiber Bragg grating sensing network consists of about one hundred and thirty FBG sensors mounted in 31 monitoring sections respectively, had been built during three years time. Signal cables of sensors were led to central control room located near the main tower. One four-channel FBG interrogator was used to read the wavelengths from all the sensors, associated with four computer-controlled optic switches connected to each channel. One program was written to control the interrogator and optic switches simultaneously, and ensure signal input precisely. The progress of the monitoring can be controlled through the internet. The sensors embedded were mainly used to monitor the strain and temperature of the steel cable and reinforced concrete beam. PE jacket opening embedding technique of steel cable had been developed to embed FBG sensors safely, and ensure the reliability of the steel cable opened at the same time. Data obtained during the load test can show the strain and temperature status of elements were in good condition. The data obtained via internet since the bridge's opening to traffic shown the bridge under various load such as traffic load, wind load were in good condition.

  17. Crystal structure of dimeric cardiac L-type calcium channel regulatory domains bridged by Ca[superscript 2+]·calmodulins

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fallon, Jennifer L.; Baker, Mariah R.; Xiong, Liangwen

    2009-11-10

    Voltage-dependent calcium channels (Ca(V)) open in response to changes in membrane potential, but their activity is modulated by Ca(2+) binding to calmodulin (CaM). Structural studies of this family of channels have focused on CaM bound to the IQ motif; however, the minimal differences between structures cannot adequately describe CaM's role in the regulation of these channels. We report a unique crystal structure of a 77-residue fragment of the Ca(V)1.2 alpha(1) subunit carboxyl terminus, which includes a tandem of the pre-IQ and IQ domains, in complex with Ca(2+).CaM in 2 distinct binding modes. The structure of the Ca(V)1.2 fragment is anmore » unusual dimer of 2 coiled-coiled pre-IQ regions bridged by 2 Ca(2+).CaMs interacting with the pre-IQ regions and a canonical Ca(V)1-IQ-Ca(2+).CaM complex. Native Ca(V)1.2 channels are shown to be a mixture of monomers/dimers and a point mutation in the pre-IQ region predicted to abolish the coiled-coil structure significantly reduces Ca(2+)-dependent inactivation of heterologously expressed Ca(V)1.2 channels.« less

  18. Comparison of erosion and channel characteristics

    USGS Publications Warehouse

    Parker, Gene W.

    1998-01-01

    Erosion was observed at 33 percent of 22,495 bridge sites in nine States. Among sites with erosion, 56 percent were associated with skewed flows, curved channels, or a combination of these two conditions, and at 18 percent of the sites, channels were straight with steep bank angles. The remaining 26 percent are sites with observable erosion at piers or abutments on straight channels. Comparison of the sites with erosion to channel bed-material indicate that 44 percent of the single-span sites had gravel-size or smaller bed material and 70 percent of the multiple-span sites had gravel-size or smaller bed material.

  19. IBRD sonar scour monitoring project : real-time river channel-bed monitoring at the Chariton and Mississippi Rivers in Missouri, 2007-09, final report, January 2010.

    DOT National Transportation Integrated Search

    2010-01-01

    Scour and depositional responses to hydrologic events have been important to the scientific community studying sediment transport as well as potential effects on bridges and other hydraulic structures within riverine systems. A river channel-bed moni...

  20. 76 FR 49662 - Drawbridge Operation Regulation; Grassy Sound Channel, Middle Township, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-11

    ... accommodate racers in ``The Wild Half'' half marathon. This deviation allows the bridge to remain in the closed position to ensure safe passage for the half marathon racers. DATES: This deviation is effective... Sound Channel, mile 1.0, at Middle Township, NJ. The route of ``The Wild Half'' half marathon crosses...

  1. Mechanism of Cd2+-coordination during Slow Inactivation in Potassium Channels

    PubMed Central

    Raghuraman, H.; Cordero-Morales, Julio F.; Jogini, Vishwanath; Pan, Albert C.; Kollewe, Astrid; Roux, Benoît; Perozo, Eduardo

    2013-01-01

    Summary In K+ channels, rearrangements of the pore outer-vestibule have been associated with C-type inactivation gating. Paradoxically, the crystal structure of Open/C-type inactivated KcsA suggest these movements to be modest in magnitude. Here, we show that under physiological conditions, the KcsA outer-vestibule undergoes relatively large dynamic rearrangements upon inactivation. External Cd2+ enhances the rate of C-type inactivation in an outer-vestibule cysteine mutant (Y82C) via metal-bridge formation. This effect is not present in a non-inactivating mutant (E71A/Y82C). Tandem dimer and tandem tetramer constructs of equivalent cysteine mutants in KcsA and Shaker K+ channels demonstrate that these Cd2+ metal bridges are formed only between adjacent subunits. This is well supported by molecular dynamics simulations. Based on the crystal structure of Cd2+-bound Y82C-KcsA in the closed state, together with EPR distance measurements in the KcsA outer-vestibule, we suggest that subunits must dynamically come in close proximity as the channels undergo inactivation. PMID:22771214

  2. Design, synthesis, insecticidal activity, and structure-activity relationship (SAR): studies of novel triazone derivatives containing a urea bridge group based on transient receptor potential (TRP) channels.

    PubMed

    Yang, Yan; Liu, Yuxiu; Song, Hongjian; Li, Yongqiang; Wang, Qingmin

    2016-11-01

    Numerous compounds containing urea bridge and biurea moieties are used in a variety of fields, especially as drugs and pesticides. To search for novel, environmentally benign and ecologically safe pesticides with unique modes of action, four series of novel triazone analogues containing urea, thiourea, biurea, and thiobiurea bridge, respectively, were designed and synthesized, according to various calcium ion channel inhibitors which act on transient receptor potential protein. Their structures were characterized by [Formula: see text] NMR, [Formula: see text] NMR, and HRMS. The insecticidal activities of the new compounds were obtained. The bioassay results indicated that compounds containing a thiourea bridge and a thiobiurea bridge exhibited excellent insecticidal activities against bean aphid. Specifically, compounds [Formula: see text], [Formula: see text], and [Formula: see text] exhibited 85, 90, and 95 % activities, respectively, at 10 mg/kg. Compounds [Formula: see text] (30 %), [Formula: see text] (35 %), [Formula: see text] (30 %), and [Formula: see text] (40 %) exhibited the approximate aphicidal activity of pymetrozine (30 %) at 5 mg/kg. In addition, some target compounds exhibited insecticidal activities against lepidopteran pests. From a molecular design standpoint, the information obtained in this study could help in the further design of new derivatives with improved insecticidal activities.

  3. Specific conductance and water temperature data for San Francisco Bay, California, for Water Year 2004

    USGS Publications Warehouse

    Buchanan, P.A.

    2005-01-01

    This article presents time-series graphs of specificconductance and water-temperature data collected in San Francisco Bay during water year 2004 (October 1, 2003, through September 30, 2004). Specific-conductance and water-temperature data were recorded at 15-minute intervals at seven U.S. Geological Survey (USGS) locations (Figure 1, Table 1). Specific-conductance and water-temperature data from Point San Pablo (PSP) and San Mateo Bridge (SMB) were recorded by the California Department of Water Resources (DWR) before 1988, by the USGS National Research Program from 1988 to 1989, and by the USGSDWR cooperative program since 1990. Benicia Bridge (BEN), Carquinez Bridge (CARQ), and Napa River (NAP) were established in 1998 by the USGS. San Pablo Bay (SPB) was initially established in 1998 at Channel Marker 9 but was moved to Channel Marker 1 in 2003. The monitoring station at Alcatraz (ALC) was established in 2003 by the USGS to replace the discontinued monitoring station San Francisco Bay at Presidio Military Reservation.

  4. Field performance of an acoustic scour-depth monitoring system

    USGS Publications Warehouse

    Mason, Jr., Robert R.; Sheppard, D. Max

    1994-01-01

    The Herbert C. Bonner Bridge over Oregon Inlet serves as the only land link between Bodie and Hatteras Islands, part of the Outer Banks of North Carolina. Periodic soundings over the past 30 years have documented channel migration, local scour, and deposition at several pilings that support the bridge. In September 1992, a data-collection system was installed to permit the off-site monitoring of scour at 16 bridge pilings. The system records channel-bed elevations at 15-minute intervals and transmits the data to a satellite receiver. A cellular phone connection also permits downloading and reviewing of the data as they are being collected. A digitally recording, acoustic fathometer is the main component of the system. In November 1993, current velocity, water-surface elevation, wave characteristics, and water temperature measuring instruments were also deployed at the site. Several performance problems relating to the equipment and to the harsh marine environment have not been resolved, but the system has collected and transmitted reliable scour-depth and water-level data.

  5. Analysis of Static Load Test of a Masonry Arch Bridge

    NASA Astrophysics Data System (ADS)

    Shi, Jing-xian; Fang, Tian-tian; Luo, Sheng

    2018-03-01

    In order to know whether the carrying capacity of the masonry arch bridge built in the 1980s on the shipping channel entering and coming out of the factory of a cement company can meet the current requirements of Level II Load of highway, through the equivalent load distribution of the test vehicle according to the current design specifications, this paper conducted the load test, evaluated the bearing capacity of the in-service stone arch bridge, and made theoretical analysis combined with Midas Civil. The results showed that under the most unfavorable load conditions the measured strain and deflection of the test sections were less than the calculated values, the bridge was in the elastic stage under the design load; the structural strength and stiffness of the bridge had a certain degree of prosperity, and under the in the current conditions of Level II load of highway, the bridge structure was in a safe state.

  6. The effects of transistor source-to-gate bridging faults in complex CMOS gates

    NASA Astrophysics Data System (ADS)

    Visweswaran, G. S.; Ali, Akhtar-Uz-Zaman M.; Lala, Parag K.; Hartmann, Carlos R. P.

    1991-06-01

    A study of the effect of gate-to-source bridging faults in the pull-up section of a complex CMOS gate is presented. The manifestation of these faults depends on the resistance value of the connection causing the bridging. It is shown that such faults manifest themselves either as stuck-at or stuck-open faults and can be detected by tests for stuck-at and stuck-open faults generated for the equivalent logic current. It is observed that for transistor channel lengths larger than 1 microns there exists a range of values of the bridging resistance for which the fault behaves as a pseudo-stuck-open fault.

  7. 33. Three bolts on railing outside control house on north ...

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

    33. Three bolts on railing outside control house on north tower, one bolt on first handrail post of the north span (bridge is in the open position). As the bridge opens or closes the single bolt on the handrail post moves past the three stationary bolts. This system is used by the bridge operator to judge speed and position of the north span as it opens or closes. Based on these bolts movement of the north span is speeded up or slowed down and the brakes applied during the opening and closing process. View facing east. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  8. Level II scour analysis for Bridge 28 (BRNATH00660028) on Town Highway 66, crossing Locust Creek, Barnard, Vermont

    USGS Publications Warehouse

    Severence, Timothy

    1997-01-01

    The Town Highway 66 crossing of the Locust Creek is a 41-ft-long, one-lane bridge consisting of a 39 ft steel stringer type bridge with a concrete deck (Vermont Agency of Transportation, written communication, August 24, 1994). The clear span is 36.8 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The upstream right wingwall is protected by stone fill. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is 0 degrees. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.

  9. Flood-plain and channel aggradation of selected bridge sites in the Iowa and Skunk River basins, Iowa

    USGS Publications Warehouse

    Eash, D.A.

    1996-01-01

    Flood-plain and channel-aggradation rates were estimated at 10 bridge sites on the Iowa River upstream of Coralville Lake and at two bridge sites in the central part of the Skunk River Basin. Four measurement methods were used to quantify aggradation rates: (1) a dendrogeomorphic method that used tree-age data and sediment-deposition depths, (2) a bridge-opening cross-section method that compared historic and recent cross sections of bridge openings, (3) a stage-discharge rating-curve method that compared historic and recent stages for the 5-year flood discharge and the average discharge, and (4) nine sediment pads that were installed on the Iowa River flood plain at three bridge sites in the vicinity of Marshalltown. The sediment pads were installed prior to overbank flooding in 1993. Sediments deposited on the pads as a result of the 1993 flood ranged in depth from 0.004 to 2.95 feet. Measurement periods used to estimate average aggradation rates ranged from 1 to 98 years and varied among methods and sites. The highest aggradation rates calculated for the Iowa River Basin using the dendrogeomorphic and rating- curve measurement methods were for the State Highway 14 crossing at Marshalltown, where these highest rates were 0.045 and 0.124 feet per year, respectively. The highest aggradation rates calculated for the Skunk River Basin were for the U.S. Highway 63 crossing of the South Skunk River near Oskaloosa, where these highest rates were 0.051 and 0.298 feet per year, respectively.

  10. Dynamics of liquid bridges inside microchannels subject to pure oscillatory flows

    NASA Astrophysics Data System (ADS)

    Ahmadlouydarab, Majid; Azaiez, Jalel; Chen, Zhangxin

    2014-11-01

    We report on 2D simulations of liquid bridges' dynamics in microchannels of uniform wettability and subject to external oscillatory flows. The flow equations were solved using the Cahn-Hilliard diffuse-interface formulation and the finite element method with unstructured grid. It was found that regardless of the wettability properties of the microchannel walls, there is a critical frequency above which the bridge shows perpetual periodic oscillatory motion. Below that critical frequency, the liquid bridge ruptures when the channel walls are philic and detaches from the surface when they are phobic. This critical frequency depends on the viscosity ratio, oscillation amplitude and geometric aspect ratio of the bridge. It was also found that the flow velocity is out of phase with the footprint/throat lengths and that the latter two show a phase difference. These differences were explained in terms of the motion of the two contact lines on the substrates and the deformation of the fluid-fluid interfaces. To characterize the behavior of the liquid bridge, two quantitative parameters; the liquid bridge-solid interfacial length and the length of the throat of the liquid bridge were used. Variations of the interfacial morphology development of the bridge were analyzed to understand the bridge response.

  11. 7. CLOSEUP VIEW OF THE PUMP DISCHARGE CHANNEL, AND THE ...

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

    7. CLOSEUP VIEW OF THE PUMP DISCHARGE CHANNEL, AND THE DISCHARGE WEIR OF THE FOR PUMPS NO. 2 AND 3, LOOKING NORTHEAST. THE SERVICE BRIDGE PROVIDED ACCESS TO THE LEVEE OVER TOBY CREEK. - Wyoming Valley Flood Control System, Woodward Pumping Station, East of Toby Creek crossing by Erie-Lackawanna Railroad, Edwardsville, Luzerne County, PA

  12. Peptides and genes coding for scorpion toxins that affect ion-channels.

    PubMed

    Possani, L D; Merino, E; Corona, M; Bolivar, F; Becerril, B

    2000-01-01

    Most scorpion toxins are ligand peptides that recognize and bind to integral membrane proteins known as ion-channels. To date there are at least 202 distinct sequences described, obtained from 30 different species of scorpions, 27 from the family Buthidae and three from the family Scorpionidae. Toxins that recognize potassium and chloride channels are usually from 29 to 41 amino acids long, stabilized by three or four disulfide bridges, whereas those that recognize sodium channels are longer, 60 to 76 amino acid residues, compacted by four disulfide bridges. Toxins specific for calcium channels are scarcely known and have variable amino acid lengths. The entire repertoire of toxins, independently of their specificity, was analyzed together by computational programs and a phylogenetic tree was built showing two separate branches. The K(+) and Cl(-) channel specific toxins are clustered into 14 subfamilies, whereas those of Na(+) and Ca(2+) specific toxins comprise at least 12 subfamilies. There are clear similarities among them, both in terms of primary sequence and the main three-dimensional folding pattern. A dense core formed by a short alpha helix segment and several antiparallel beta-sheet stretches, maintained by disulfide pairing, seems to be a common structural feature present in all toxins. The physiological function of these peptides is manifested by a blockage of ion passage through the channels or by a modification of the gating mechanism that controls opening and closing of the ion pore.

  13. Exploring Strong Interactions in Proteins with Quantum Chemistry and Examples of Their Applications in Drug Design.

    PubMed

    Xie, Neng-Zhong; Du, Qi-Shi; Li, Jian-Xiu; Huang, Ri-Bo

    2015-01-01

    Three strong interactions between amino acid side chains (salt bridge, cation-π, and amide bridge) are studied that are stronger than (or comparable to) the common hydrogen bond interactions, and play important roles in protein-protein interactions. Quantum chemical methods MP2 and CCSD(T) are used in calculations of interaction energies and structural optimizations. The energies of three types of amino acid side chain interactions in gaseous phase and in aqueous solutions are calculated using high level quantum chemical methods and basis sets. Typical examples of amino acid salt bridge, cation-π, and amide bridge interactions are analyzed, including the inhibitor design targeting neuraminidase (NA) enzyme of influenza A virus, and the ligand binding interactions in the HCV p7 ion channel. The inhibition mechanism of the M2 proton channel in the influenza A virus is analyzed based on strong amino acid interactions. (1) The salt bridge interactions between acidic amino acids (Glu- and Asp-) and alkaline amino acids (Arg+, Lys+ and His+) are the strongest residue-residue interactions. However, this type of interaction may be weakened by solvation effects and broken by lower pH conditions. (2) The cation- interactions between protonated amino acids (Arg+, Lys+ and His+) and aromatic amino acids (Phe, Tyr, Trp and His) are 2.5 to 5-fold stronger than common hydrogen bond interactions and are less affected by the solvation environment. (3) The amide bridge interactions between the two amide-containing amino acids (Asn and Gln) are three times stronger than hydrogen bond interactions, which are less influenced by the pH of the solution. (4) Ten of the twenty natural amino acids are involved in salt bridge, or cation-, or amide bridge interactions that often play important roles in protein-protein, protein-peptide, protein-ligand, and protein-DNA interactions.

  14. Thomas Spencer Wells, Bt FRCS (1818-97) and his contributions to naval medicine.

    PubMed

    Cook, G C

    2007-05-01

    Sir Thomas Spencer Wells (1818-97) is best remembered both as a gynaecological surgeon, who introduced ovariectomy, and as the one who introduced the surgical forceps named after him. Far less is known of his career in the Royal Navy (RN) as an assistant surgeon and then a surgeon, and his contributions to naval medicine. Wells enlisted for the RN at the age of 23 years and for most of his naval career (1841-56) he served at the Naval Hospital, Malta (1841-48). However, from 1851 to 1853 he was surgeon and sanitary officer on the sloop, HMS Modeste. Most of Wells' contributions to the health of sailors were of a preventive nature, especially involving ventilation, in RN ships. He was also an enthusiast for quarantine and vaccination.

  15. Drowned reefs and antecedent karst topography, Au'au channel, S.E. Hawaiian Islands

    USGS Publications Warehouse

    Grigg, R.W.; Grossman, E.E.; Earle, S.A.; Gittings, S.R.; Lott, D.; McDonough, J.

    2002-01-01

    During the last glacial maximum (LGM), about 21,000 years ago, the Hawaiian Islands of Maui, Lanai, and Molokai were interconnected by limestone bridges, creating a super-island known as Maui-Nui. Approximately 120 m of sea-level rise during the Holocene Transgression flooded, and then drowned, these bridges separating the islands by inter-island channels. A new multibeam high-resolution bathymetric survey of the channels between the islands, coupled with observations and video-transects utilizing DeepWorker-2000 submersibles, has revealed the existence of numerous drowned reef features including concentric solution basins, solution ridges (rims), sand and sediment plains, and conical-shaped reef pinnacles. The concentric basins contain flat lagoon-like bottoms that are rimmed by steep-sided limestone walls. Undercut notches rim the basins at several depths, marking either sea-level still stands or paleo-lake levels. All of the solution basins shallower than 120 m were subaerial at the LGM, and at one stage or another may have been shallow shoreline lakes. Today, about 70 drowned reef pinnacles are scattered across the Maui-Lanai underwater bridge and all are situated in wave-sheltered positions. Most drowned during the interval between 14,000 and 10,000 years ago when sea-level rise averaged 15 mm/year. Virtually all of the surficial topography in the Au'au Channel today is a product of karst processes accentuated by marginal reef growth during the Holocene. Both the submerged basins and the drowned reefs represent an archive of sea-level and climate history in Hawaii during the late Quaternary.

  16. Down-state model of the voltage-sensing domain of a potassium channel.

    PubMed

    Schow, Eric V; Freites, J Alfredo; Gogna, Karun; White, Stephen H; Tobias, Douglas J

    2010-06-16

    Voltage-sensing domains (VSDs) of voltage-gated potassium (Kv) channels undergo a series of conformational changes upon membrane depolarization, from a down state when the channel is at rest to an up state, all of which lead to the opening of the channel pore. The crystal structures reported to date reveal the pore in an open state and the VSDs in an up state. To gain insights into the structure of the down state, we used a set of experiment-based restraints to generate a model of the down state of the KvAP VSD using molecular-dynamics simulations of the VSD in a lipid bilayer in excess water. The equilibrated VSD configuration is consistent with the biotin-avidin accessibility and internal salt-bridge data used to generate it, and with additional biotin-avidin accessibility data. In the model, both the S3b and S4 segments are displaced approximately 10 A toward the intracellular side with respect to the up-state configuration, but they do not move as a rigid body. Arginine side chains that carry the majority of the gating charge also make large excursions between the up and down states. In both states, arginines interact with water and participate in salt bridges with acidic residues and lipid phosphate groups. An important feature that emerges from the down-state model is that the N-terminal half of the S4 segment adopts a 3(10)-helical conformation, which appears to be necessary to satisfy a complex salt-bridge network. (c) 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  17. Down-State Model of the Voltage-Sensing Domain of a Potassium Channel

    PubMed Central

    Schow, Eric V.; Freites, J. Alfredo; Gogna, Karun; White, Stephen H.; Tobias, Douglas J.

    2010-01-01

    Abstract Voltage-sensing domains (VSDs) of voltage-gated potassium (Kv) channels undergo a series of conformational changes upon membrane depolarization, from a down state when the channel is at rest to an up state, all of which lead to the opening of the channel pore. The crystal structures reported to date reveal the pore in an open state and the VSDs in an up state. To gain insights into the structure of the down state, we used a set of experiment-based restraints to generate a model of the down state of the KvAP VSD using molecular-dynamics simulations of the VSD in a lipid bilayer in excess water. The equilibrated VSD configuration is consistent with the biotin-avidin accessibility and internal salt-bridge data used to generate it, and with additional biotin-avidin accessibility data. In the model, both the S3b and S4 segments are displaced ∼10 Å toward the intracellular side with respect to the up-state configuration, but they do not move as a rigid body. Arginine side chains that carry the majority of the gating charge also make large excursions between the up and down states. In both states, arginines interact with water and participate in salt bridges with acidic residues and lipid phosphate groups. An important feature that emerges from the down-state model is that the N-terminal half of the S4 segment adopts a 310-helical conformation, which appears to be necessary to satisfy a complex salt-bridge network. PMID:20550898

  18. Yield enhancement of 3D flash devices through broadband brightfield inspection of the channel hole process module

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Youl; Seo, Il-Seok; Ma, Seong-Min; Kim, Hyeon-Soo; Kim, Jin-Woong; Kim, DoOh; Cross, Andrew

    2013-03-01

    The migration to a 3D implementation for NAND flash devices is seen as the leading contender to replace traditional planar NAND architectures. However the strategy of replacing shrinking design rules with greater aspect ratios is not without its own set of challenges. The yield-limiting defect challenges for the planar NAND front end were primarily bridges, protrusions and residues at the bottom of the gates, while the primary challenges for front end 3D NAND is buried particles, voids and bridges in the top, middle and bottom of high aspect ratio structures. Of particular interest are the yield challenges in the channel hole process module and developing an understanding of the contribution of litho and etch defectivity for this challenging new integration scheme. The key defectivity and process challenges in this module are missing, misshapen channel holes or under-etched channel holes as well as reducing noise sources related to other none yield limiting defect types and noise related to the process integration scheme. These challenges are expected to amplify as the memory density increases. In this study we show that a broadband brightfield approach to defect monitoring can be uniquely effective for the channel hole module. This approach is correlated to end-of-line (EOL) Wafer Bin Map for verification of capability.

  19. Hydrology, geomorphology, and flood profiles of Lemon Creek, Juneau, Alaska

    USGS Publications Warehouse

    Host, Randy H.; Neal, Edward G.

    2005-01-01

    Lemon Creek near Juneau, Alaska has a history of extensive gravel mining, which straightened and deepened the stream channel in the lower reaches of the study area. Gravel mining and channel excavation began in the 1940s and continued through the mid-1980s. Time sequential aerial photos and field investigations indicate that the channel morphology is reverting to pre-disturbance conditions through aggradation of sediment and re-establishment of braided channels, which may result in decreased channel conveyance and increased flooding potential. Time sequential surveys of selected channel cross sections were conducted in an attempt to determine rates of channel aggradation/degradation throughout three reaches of the study area. In order to assess flooding potential in the lower reaches of the study area the U.S. Army Corps of Engineers Hydrologic Engineering Center River Analysis System model was used to estimate the water-surface elevations for the 2-, 10-, 25-, 50-, and 100-year floods. A regionally based regression equation was used to estimate the magnitude of floods for the selected recurrence intervals. Forty-two cross sections were surveyed to define the hydraulic characteristics along a 1.7-mile reach of the stream. High-water marks from a peak flow of 1,820 cubic feet per second, or about a 5-year flood, were surveyed and used to calibrate the model throughout the study area. The stream channel at a bridge in the lower reach could not be simulated without violating assumptions of the model. A model without the lower bridge indicates flood potential is limited to a small area.

  20. Thermally induced charge current through long molecules

    NASA Astrophysics Data System (ADS)

    Zimbovskaya, Natalya A.; Nitzan, Abraham

    2018-01-01

    In this work, we theoretically study steady state thermoelectric transport through a single-molecule junction with a long chain-like bridge. Electron transmission through the system is computed using a tight-binding model for the bridge. We analyze dependences of thermocurrent on the bridge length in unbiased and biased systems operating within and beyond the linear response regime. It is shown that the length-dependent thermocurrent is controlled by the lineshape of electron transmission in the interval corresponding to the HOMO/LUMO transport channel. Also, it is demonstrated that electron interactions with molecular vibrations may significantly affect the length-dependent thermocurrent.

  1. Bathymetric and velocimetric surveys at highway bridges crossing the Missouri River between Kansas City and St. Louis, Missouri, April-May, 2013

    USGS Publications Warehouse

    Huizinga, Richard J.

    2014-01-01

    Bathymetric and velocimetric data were collected by the U.S. Geological Survey, in cooperation with the Missouri Department of Transportation, in the vicinity of 10 bridges at 9 highway crossings of the Missouri River between Lexington and Washington, Missouri, from April 22 through May 2, 2013. A multibeam echosounder mapping system was used to obtain channel-bed elevations for river reaches ranging from 1,640 to 1,840 feet longitudinally and extending laterally across the active channel between banks and spur dikes in the Missouri River during low- to moderate-flow conditions. These bathymetric surveys indicate the channel conditions at the time of the surveys and provide characteristics of scour holes that may be useful in the development of predictive guidelines or equations for scour holes. These data also may be useful to the Missouri Department of Transportation to assess the bridges for stability and integrity issues with respect to bridge scour during floods. Bathymetric data were collected around every pier that was in water, except those at the edge of water or in very shallow water (less than about 6 feet). Scour holes were present at most piers for which bathymetry could be obtained, except at piers on channel banks, near or embedded in lateral or longitudinal spur dikes, and on exposed bedrock outcrops. Scour holes observed at the surveyed bridges were examined with respect to depth and shape. Although exposure of parts of foundational support elements was observed at several piers, at most sites the exposure likely can be considered minimal compared to the overall substructure that remains buried in channel-bed material; however, there were several notable exceptions where the bed material thickness between the bottom of the scour hole and bedrock was less than 6 feet. Such substantial exposure of usually buried substructural elements may warrant special observation in future flood events. Previous bathymetric surveys had been done at all of the sites in this study during the flood of 2011. Comparisons between bathymetric surfaces from the previous surveys and those of this study generally indicate a consistent increase in the elevation of the bed and decrease in the size of scour holes at these sites, both likely caused by a substantial decrease in discharge and water-surface elevation compared to the 2011 surveys at most sites. However, multiple surveys at one of the sites indicate that the flow condition is not the sole variable in the determination of the size of scour holes at sites with a dual bridge configuration. Furthermore, another site had a smaller and shallower scour hole even though the discharge in this study was slightly greater than in 2011. Pier size, nose shape, and alignment to flow also had a substantial effect on the size of the scour hole observed.

  2. General Model Study of Scour at Proposed Pier Extensions - Santa Ana River at BNSF Bridge, Corona, California

    DTIC Science & Technology

    2017-11-01

    model of the bridge piers, other related structures, and the adjacent channel. Data from the model provided a qualitative and quantitative evaluation of...minus post-test lidar survey . ......................... 42 Figure 38. Test 1 (30,000 cfs existing conditions) pre- minus post-test lidar survey ...43 Figure 39. Test 7 (15,000 cfs original proposed conditions) pre- minus post-test lidar survey

  3. Simulations of flow and prediction of sediment movement in Wymans Run, Cochranton Borough, Crawford County, Pennsylvania

    USGS Publications Warehouse

    Hittle, Elizabeth

    2011-01-01

    In small watersheds, runoff entering local waterways from large storms can cause rapid and profound changes in the streambed that can contribute to flooding. Wymans Run, a small stream in Cochranton Borough, Crawford County, experienced a large rain event in June 2008 that caused sediment to be deposited at a bridge. A hydrodynamic model, Flow and Sediment Transport and Morphological Evolution of Channels (FaSTMECH), which is incorporated into the U.S. Geological Survey Multi-Dimensional Surface-Water Modeling System (MD_SWMS) was constructed to predict boundary shear stress and velocity in Wymans Run using data from the June 2008 event. Shear stress and velocity values can be used to indicate areas of a stream where sediment, transported downstream, can be deposited on the streambed. Because of the short duration of the June 2008 rain event, streamflow was not directly measured but was estimated using U.S. Army Corps of Engineers one-dimensional Hydrologic Engineering Centers River Analysis System (HEC-RAS). Scenarios to examine possible engineering solutions to decrease the amount of sediment at the bridge, including bridge expansion, channel expansion, and dredging upstream from the bridge, were simulated using the FaSTMECH model. Each scenario was evaluated for potential effects on water-surface elevation, boundary shear stress, and velocity.

  4. Bridging kinematics and concentration content in a chaotic micromixer.

    PubMed

    Villermaux, E; Stroock, A D; Stone, H A

    2008-01-01

    We analyze the mixing properties of the microfluidic herringbone configuration introduced to mix scalar substances in a narrow channel at low Reynolds but large Péclet numbers. Because of the grooves sculpted on the channel floor, substantial transverse motions are superimposed onto the usual longitudinal Poiseuille dispersion along the channel, whose impact on both the mixing rate and mixture content is quantified. We demonstrate the direct link between the flow kinematics and the deformation rate of the mixture's concentration distribution, whose overall shape is also determined.

  5. Bathymetric and velocimetric surveys at highway bridges crossing the Missouri River near Kansas City, Missouri, June 2–4, 2015

    USGS Publications Warehouse

    Huizinga, Richard J.

    2016-06-22

    A local spatial minimum average channel-bed elevation at structure A7650 (site 10) compared to adjacent sites may indicate this site is at or near a local feature that controls sediment deposition and scour. The average channel-bed elevation values and the distribution of channel-bed elevations imply that sediment unable to deposit near structure A7650 is flushed downstream and deposits at the next downstream site, structure A5817 (site 11).

  6. TRPM channels phosphorylation as a potential bridge between old signals and novel regulatory mechanisms of insulin secretion.

    PubMed

    Diaz-Garcia, Carlos Manlio; Sanchez-Soto, Carmen; Hiriart, Marcia

    2013-03-01

    Transient receptor potential channels, especially the members of the melastatin family (TRPM), participate in insulin secretion. Some of them are substrates for protein kinases, which are involved in several neurotransmitter, incretin and hormonal signaling cascades in β cells. The functional relationships between protein kinases and TRPM channels in systems of heterologous expression and native tissues rise issues about novel regulation pathways of pancreatic β-cell excitability. The aim of the present work is to review the evidences about phosphorylation of TRPM channels in β cells and to discuss the perspectives on insulin secretion.

  7. Spatial-temporal fluvial morphology analysis in the Quelite river: It's impact on communication systems

    NASA Astrophysics Data System (ADS)

    Ramos, Judith; Gracia, Jesús

    2012-01-01

    SummaryDuring 2008 and 2009 heavy rainfall took place around the Mazatlan County in the Sinaloa state, Mexico, with a return period (Tr) between 50 and 100 years. As a result, the region and its infrastructure, such as the railways and highways (designed for a Tr = 20 years) were severely exposed to floods and, as a consequence damage caused by debris and sediments dragged into the channel. One of the highest levels of damage to the infrastructure was observed in the columns of Quelite River railway's bridge. This is catastrophic as the railway is very important for trade within the state and also among other states in Mexico and in the USA. In order to understand the impact of the flooding and to avoid the rail system being damaged it is necessary to analyse how significant the changes in the river channel have been. This analysis looks at the definition of the main channel and its floodplain as a result of the sediment variability, not only at the bridge area, but also upstream and downstream. The Quelite River study considers the integration of Geographic Information Systems (GIS) and remote sensing data to map, recognise and assess the spatio-temporal change channel morphology. This increases the effectiveness of using different types of geospatial data with in situ measurements such as hydrological data. Thus, this paper is an assessment of a 20 years study period carried out using historical Landsat images and aerial photographs as well as recent Spot images. A Digital Elevation Model (DEM) of local topography and flow volumes were also used. The results show the Quelite River is an active river with a high suspended sediment load and migration of meanders associated to heavy rainfall. The river also has several deep alluvial floodplain channels which modified the geometry and other morphological characteristics of the channel in the downstream direction. After the identification of the channel changes, their causes and solutions to control, the channel migration and the dynamics structure, a river management plan was projected not only to protect the bridge but also to provide a flood risk awareness in order to reduce the social-economical impact during a flood event.

  8. Development and application of a modified wireless tracer for disaster prevention

    NASA Astrophysics Data System (ADS)

    Chung Yang, Han; Su, Chih Chiang

    2016-04-01

    Typhoon-induced flooding causes water overflow in a river channel, which results in general and bridge scour and soil erosion, thus leading to bridge failure, debris flow and landslide collapse. Therefore, dynamic measurement technology should be developed to assess scour in channels and landslide as a disaster-prevention measure against bridge failure and debris flow. This paper presents a wireless tracer that enables monitoring general scour in river channels and soil erosion in hillsides. The wireless tracer comprises a wireless high-power radio modem, various electronic components, and a self-designed printed circuit board that are all combined with a 9-V battery pack and an auto switch. The entire device is sealed in a jar by silicon. After it was modified, the wireless tracer underwent the following tests for practical applications: power continuation and durability, water penetration, and signal transmission during floating. A regression correlation between the wireless tracer's transmission signal and distance was also established. This device can be embedded at any location where scouring is monitored, and, in contrast to its counterparts that detect scour depth by identifying and analyzing received signals, it enables real-time observation of the scouring process. In summary, the wireless tracer developed in this study provides a dynamic technology for real-time monitoring of scouring (or erosion) and forecasting of landslide hazards. Keywords: wireless tracer; scour; real-time monitoring; landslide hazard.

  9. Level II scour analysis for Bridge 10 (BENNUS00070010) on U.S. Route 7, crossing the Walloomsac River, Bennington, Vermont

    USGS Publications Warehouse

    Olson, Scott A.; Burns, Ronda L.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure BENNUS00070010 on U.S. Route 7, also known as North Street, crossing of the Walloomsac River, Bennington, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in southwestern Vermont. The 30.1-mi2 drainage area is a predominantly rural and forested basin. The bridge site is located within an urban setting in the Town of Bennington with buildings, parking lots, lawns, and a playground on the overbank areas. In the study area, the Walloomsac River has a straight channel with constructed channel banks through much of the reach. The channel is located on a delta and has a slope of approximately 0.02 ft/ft, an average channel top width of 37 ft and an average bank height of 5 ft. The predominant channel bed material is cobble with a median grain size (D50) of 96.0 mm (0.315 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 5, 1996, indicated that the constructed reach was stable. The U.S. Route 7 crossing of the Walloomsac River is a 53-ft-long, two-lane bridge consisting of one 50-foot steel span (Vermont Agency of Transportation, written communication, September 27, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The wingwalls are angled in toward the channel because the widths of the upstream and downstream constructed channel banks are narrower than the bridge opening. The channel is skewed approximately 5 degrees to the opening and the opening-skew-to-roadway is 10 degrees. Scour countermeasures at the site include masonry and stone walls on both the upstream and downstream banks. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour computed for all modelled flows ranged from 0.0 to 0.1 ft. The worstcase contraction scour occurred at the 500-year discharge. Computed left abutment scour ranged from 5.9 to 6.8 ft. with the worst-case scour occurring at the 500-year discharge. Computed right abutment scour for all modelled flows was 6.8 ft. Total scour depths for all modelled flows did not exceed the depth of the abutment footings. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  10. Wind-Driven Formation of Ice Bridges in Straits.

    PubMed

    Rallabandi, Bhargav; Zheng, Zhong; Winton, Michael; Stone, Howard A

    2017-03-24

    Ice bridges are static structures composed of tightly packed sea ice that can form during the course of its flow through a narrow strait. Despite their important role in local ecology and climate, the formation and breakup of ice bridges is not well understood and has proved difficult to predict. Using long-wave approximations and a continuum description of sea ice dynamics, we develop a one-dimensional theory for the wind-driven formation of ice bridges in narrow straits, which is verified against direct numerical simulations. We show that for a given wind stress and minimum and maximum channel widths, a steady-state ice bridge can only form beyond a critical value of the thickness and the compactness of the ice field. The theory also makes quantitative predictions for ice fluxes, which are particularly useful to estimate the ice export associated with the breakup of ice bridges. We note that similar ideas are applicable to dense granular flows in confined geometries.

  11. Temporal and spatial patterns of wetland sedimentation, West Tennessee

    USGS Publications Warehouse

    Hupp, C.R.; Bazemore, D.E.

    1993-01-01

    Dendrogeomorphic techniques were used to describe and interpret patterns of sedimentation rates at two forested wetland sites in West Tennessee. Fifty-five sampling stations were established along transects upstream and downstream from bridge structures, and 515 trees were examined for depth of sediment accretion and cored for age determination. Temporal variation in sedimentation rate may be related more to stream channelization and agricultural activity than to bridge and causeway construction. Sedimentation rates have increased substantially in the last 28 years, although channelized streams may have overall lower rates than unchannelized streams. Comparisons of sedimentation rates from deposition over artificial markers (short term) with those determined from tree-ring analysis (long-term) indicate that trends are similar where hydrogeomorphic conditions have not been altered substantially. No tendency for increased sedimentation upstream from bridges was observed. Deposition rates were inversely correlated with elevation and degree of ponding. Downstream deposition of sand splays appears to be related to flow constrictions and may be extensive. Mean overall rates of sedimentation (between 0.24 and 0.28 cm year-1), determined dendrogeomorphically, are comparable with other published rates. ?? 1993.

  12. Reference surfaces for bridge scour depths

    USGS Publications Warehouse

    Landers, Mark N.; Mueller, David S.; ,

    1993-01-01

    Depth of scour is measured as the vertical distance between scoured channel geometry and a measurement reference surface. A scour depth measurement can have a wide range depending on the method used to establish the reference surface. A consistent method to establish reference surfaces for bridge scour measurements is needed to facilitate transferability of scour data an scour analyses. This paper describes and evaluates techniques for establishing reference surfaces from which local and contraction scour are measured.

  13. 18 CFR 1304.1 - Scope and intent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., bridges, aerial cables, culverts, pipelines, fish attractors, shoreline stabilization projects, channel... subjacent to TVA reservoirs and exercises its land rights to carry out the purposes and policies of the Act...

  14. Rational design and validation of a vanilloid-sensitive TRPV2 ion channel.

    PubMed

    Yang, Fan; Vu, Simon; Yarov-Yarovoy, Vladimir; Zheng, Jie

    2016-06-28

    Vanilloids activation of TRPV1 represents an excellent model system of ligand-gated ion channels. Recent studies using cryo-electron microcopy (cryo-EM), computational analysis, and functional quantification revealed the location of capsaicin-binding site and critical residues mediating ligand-binding and channel activation. Based on these new findings, here we have successfully introduced high-affinity binding of capsaicin and resiniferatoxin to the vanilloid-insensitive TRPV2 channel, using a rationally designed minimal set of four point mutations (F467S-S498F-L505T-Q525E, termed TRPV2_Quad). We found that binding of resiniferatoxin activates TRPV2_Quad but the ligand-induced open state is relatively unstable, whereas binding of capsaicin to TRPV2_Quad antagonizes resiniferatoxin-induced activation likely through competition for the same binding sites. Using Rosetta-based molecular docking, we observed a common structural mechanism underlying vanilloids activation of TRPV1 and TRPV2_Quad, where the ligand serves as molecular "glue" that bridges the S4-S5 linker to the S1-S4 domain to open these channels. Our analysis revealed that capsaicin failed to activate TRPV2_Quad likely due to structural constraints preventing such bridge formation. These results not only validate our current working model for capsaicin activation of TRPV1 but also should help guide the design of drug candidate compounds for this important pain sensor.

  15. Streambed stability and scour potential at selected bridge sites in Michigan

    USGS Publications Warehouse

    Holtschlag, D.J.; Miller, R.L.

    1998-01-01

    Contraction scour in the main stream channel at a bridge and local scour near piers and abutments can result in bridge failure. Estimates of contraction-scour and local-scour potentials associated with the 100-year flood were computed for 13 bridge sites in Michigan by use of semi-theoretical equations and procedures recommended by the Federal Highway Administration. These potentials were compared with measures of Streambed stability obtained by use of data from 773 historical streamflow measurements, documenting 20,741 individual Streambed soundings between 1959 and 1995. Analysis of these data indicate small, but statistically significant, monotonic trends in Streambed elevation at 10 sites. No consistent patterns in relations between changes in Streambed elevations and streamflow, flow velocity, or flow depth were evident. Also, estimates of contraction-scour potential were not correlated with measures of Streambed stability, and no differences were detected between measures of Streambed stability in the main channel and stability adjacent to piers. Despite the inconsistencies between measures of Streambed stability and scour potential, data from a single, large flood (greater than a 100-year event) provided field evidence that the relation between scour and streamflow is highly nonlinear. This nonlinearity and the limited availability of measurements of extreme flood events may have reduced the utility of the empirical measures for confirming the nonlinear scour-potential equations and procedures. Results of field surveys using ground-penetrating radar and tuned transducers showed limited ability to aid interpretation of historical scour conditions at four bridge sites. Additional research is needed to confirm the applicability of scour-potential equations for hydrogeologic conditions in Michigan.

  16. Method and system for a gas tube-based current source high voltage direct current transmission system

    DOEpatents

    She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

    2017-08-29

    A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

  17. MoNET: media over net gateway processor for next-generation network

    NASA Astrophysics Data System (ADS)

    Elabd, Hammam; Sundar, Rangarajan; Dedes, John

    2001-12-01

    MoNETTM (Media over Net) SX000 product family is designed using a scalable voice, video and packet-processing platform to address applications with channel densities from few voice channels to four OC3 per card. This platform is developed for bridging public circuit-switched network to the next generation packet telephony and data network. The platform consists of a DSP farm, RISC processors and interface modules. DSP farm is required to execute voice compression, image compression and line echo cancellation algorithms for large number of voice, video, fax, and modem or data channels. RISC CPUs are used for performing various packetizations based on RTP, UDP/IP and ATM encapsulations. In addition, RISC CPUs also participate in the DSP farm load management and communication with the host and other MoP devices. The MoNETTM S1000 communications device is designed for voice processing and for bridging TDM to ATM and IP packet networks. The S1000 consists of the DSP farm based on Carmel DSP core and 32-bit RISC CPU, along with Ethernet, Utopia, PCI, and TDM interfaces. In this paper, we will describe the VoIP infrastructure, building blocks of the S500, S1000 and S3000 devices, algorithms executed on these device and associated channel densities, detailed DSP architecture, memory architecture, data flow and scheduling.

  18. Thermal Analysis of AlGaN/GaN High-Electron-Mobility Transistor and Its RF Power Efficiency Optimization with Source-Bridged Field-Plate Structure.

    PubMed

    Kwak, Hyeon-Tak; Chang, Seung-Bo; Jung, Hyun-Gu; Kim, Hyun-Seok

    2018-09-01

    In this study, we consider the relationship between the temperature in a two-dimensional electron gas (2-DEG) channel layer and the RF characteristics of an AlGaN/GaN high-electron-mobility transistor by changing the geometrical structure of the field-plate. The final goal is to achieve a high power efficiency by decreasing the channel layer temperature. First, simulations were performed to compare and contrast the experimental data of a conventional T-gate head structure. Then, a source-bridged field-plate (SBFP) structure was used to obtain the lower junction temperature in the 2-DEG channel layer. The peak electric field intensity was reduced, and a decrease in channel temperature resulted in an increase in electron mobility. Furthermore, the gate-to-source capacitance was increased by the SBFP structure. However, under the large current flow condition, the SBFP structure had a lower maximum temperature than the basic T-gate head structure, which improved the device electron mobility. Eventually, an optimum position of the SBFP was used, which led to higher frequency responses and improved the breakdown voltages. Hence, the optimized SBFP structure can be a promising candidate for high-power RF devices.

  19. Thermoelectric efficiency of single-molecule junctions with long molecular linkers.

    PubMed

    Zimbovskaya, Natalya A

    2018-06-18

    We report results of theoretical studies of thermoelectric efficiency of single-molecule junctions with long molecular linkers. The linker is simulated by a chain of identical sites described using a tight-binding model. It is shown that thermoelectric figure of merit ZT strongly depends on the bridge length, being controlled by the lineshape of electron transmission function within the tunnel energy range corresponding to HOMO/LUMO transport channel. Using the adopted model we demonstrate that ZT may significantly increase as the linker lengthens, and that gateway states on the bridge (if any) may noticeably affect the length-dependent ZT. Temperature dependences of ZT for various bridge lengths are analyzed. It is shown that broad minima emerge in ZT versus temperature curves whose positions are controlled by the bridge lengths. © 2018 IOP Publishing Ltd.

  20. Detection of magnetic microbeads and ferrofluid with giant magnetoresistance sensors

    NASA Astrophysics Data System (ADS)

    Feng, J.; Wang, Y. Q.; Li, F. Q.; Shi, H. P.; Chen, X.

    2011-01-01

    Giant magnetoresistance sensors based on multilayers [Cu/NiFeCo]×10/ Ta were fabricated by microfabrication technology. A GMR-bridge was used to detect the magnetic MyOne beads and Ferro fluid. The dependence of the GMR-bridge signals on the surface coverage of MyOne beads was studied. The results show that the GMR sensor is capable of detecting the magnetic beads. The detectable limit of MyOne beads is about 100, and the corresponding signal output is 8 μV. The GMR bridge signal is proportional to the surface coverage of the MyOne beads. The sensitivity of the GMR bridge is inversely proportional to the feature size of the GMR sensor. The GMR bridge integrated with microfludic channel was also used for dynamic detection of ferrofluid (suspension of Fe3O4 particles). The results show that the GMR bridge is capable of detecting the flow of ferrofluid, and the sensor signals are proportional to the concentration of the ferrofluid. The detection limit of concentration of the ferrofluid is 0.56 mg/ml, and the corresponding signal is 6.2 μV.

  1. 4. Photocopy of drawing (this photograph is an 8''x 10'' ...

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

    4. Photocopy of drawing (this photograph is an 8''x 10'' contact print; January, 1995 revision of a July 11, 1973 as built drawing by A. Rivera-Cruz, in possession of the Highway System Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Rio Grande de Arecibo, Route no. 2 Km. 74.75. Bridge no. 44. no. 2 of 4. - Puente del Rio Grande de Arecibo, Spanning Rio Grande de Arecibo Channel, Cambalache neighborhood, Arecibo, Arecibo Municipio, PR

  2. 5. Photocopy of drawing (this photograph is an 8''x 10'' ...

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

    5. Photocopy of drawing (this photograph is an 8''x 10'' contact print; December, 1990 as built drawing by M. Villafane, in possession of the Highway System Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Rio Grande de Arecibo, Route no. 2 Km. 74.75. Arecibo, P.R. Bridge no. 44. no. 3 of 4. - Puente del Rio Grande de Arecibo, Spanning Rio Grande de Arecibo Channel, Cambalache neighborhood, Arecibo, Arecibo Municipio, PR

  3. 6. Photocopy of drawing (this photograph is an 8''x 10'' ...

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

    6. Photocopy of drawing (this photograph is an 8''x 10'' contact print; January 4, 1995 revision of a February, 1992 as built drawing by M. Villafane, in possession of the Highway System Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Rio Grande de Arecibo, Route no. 2 Km. 74.75. Arecibo, P.R. Bridge no. 44. no. 4 of 4. - Puente del Rio Grande de Arecibo, Spanning Rio Grande de Arecibo Channel, Cambalache neighborhood, Arecibo, Arecibo Municipio, PR

  4. 3. Photocopy of drawing (this photograph is an 8''x 10'' ...

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

    3. Photocopy of drawing (this photograph is an 8''x 10'' contact print; January, 1995 revision of a October 31, 1973 as built drawing by A. Rivera-Cruz, in possession of the Highway System Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Rio Grande de Arecibo, Route no. 2 Arecibo Km. 74.40. Bridge no. 44 no. 1 of 4. - Puente del Rio Grande de Arecibo, Spanning Rio Grande de Arecibo Channel, Cambalache neighborhood, Arecibo, Arecibo Municipio, PR

  5. A Measurable Difference: Bridge Versus Loop

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Trig-Tek, Inc.'s Model 251A ACL-8 Anderson Current Loop (ACL) Conditioner is an eight channel device designed to condition variable-resistant sensor signals from Strain Gage and RTD's (Resistance Temperature Device)s. It uses NASA's patented ACL technology instead of the classic wheatstone bridge. The electronic measurement circuit delivers accuracy far beyond previous methods and prevents errors caused by variation in the wires that connect sensors to data collection equipment. This is the first license to market a NASA Dryden Flight Research Center patent.

  6. A symmetric, triply interlaced 3-D anionic MOF that exhibits both magnetic order and SMM behaviour.

    PubMed

    Campo, J; Falvello, L R; Forcén-Vázquez, E; Sáenz de Pipaón, C; Palacio, F; Tomás, M

    2016-11-14

    A newly prepared 3-D polymer of cobalt citrate cubanes bridged by high-spin Co(ii) centres displays both single-molecule magnet (SMM) behaviour and magnetic ordering. Triple interpenetration of the 3-D diamondoid polymers yields a crystalline solid with channels that host cations and free water molecules, with the SMM behaviour of the Co 4 O 4 cores preserved. The octahedrally coordinated Co(ii) bridges are implicated in the onset of magnetic order at an experimentally accessible temperature.

  7. 47. Viaduct detail showing riveted plate bracing and lattice members, ...

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

    47. Viaduct detail showing riveted plate bracing and lattice members, same double post as MA-46. - Broadway Bridge, Spanning Foundry Street, MBTA Yard, Fort Point Channel, & Lehigh Street, Boston, Suffolk County, MA

  8. 46 CFR 11.705 - Route familiarization requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... such as bridges, narrow channels, or sharp turns; and, (6) Any other factors unique to the route that... paragraph (c) of this section. (c) An applicant who currently holds a deck officer license or MMC...

  9. Bathymetric and Velocimetric Survey and Assessment of Habitat for Pallid Sturgeon on the Mississippi River in the Vicinity of the Proposed Interstate 70 Bridge at St. Louis, Missouri

    USGS Publications Warehouse

    Huizinga, Richard J.; Elliott, Caroline M.; Jacobson, Robert B.

    2010-01-01

    A bathymetric and velocimetry survey was conducted on the Mississippi River in the vicinity of a proposed new bridge for Interstate 70 at St. Louis, Missouri. A multibeam echo sounder mapping system and an acoustic Doppler current profiler were used to obtain channel-bed elevations and vertically averaged and near-bed velocities for a 3,545-foot (1,080-meter) long reach of the Mississippi River approximately 1,935 feet (590 meters) wide from the Illinois to Missouri banks. Data from the 2009 survey were used to determine the conditions of the benthic habitat in the vicinity of the proposed Interstate 70 bridge. The channel-bed elevations ranged from approximately 346 feet (105.46 meters) to 370 feet (112.78 meters) above the North American Vertical Datum of 1988 in a majority of the channel except for the channel banks. Large dune features up to 12.5 feet (3.81 meters) high were present in the middle of the channel, and numerous smaller dunes and many ripples as smaller features were superimposed on the larger dunes. However, it is uncertain if the large dune features present in mid-channel are long-term features or an artifact of the seasonal flooding on the Mississippi River. A substantial scour depression was present on the right descending bank (Missouri side) near the downstream end of the study area, as well as other smaller scour holes near the instream barge mooring structures on the Missouri bank. The vertically averaged velocities acquired with the acoustic Doppler current profiler ranged from approximately 2 feet per second (0.61 meters per second) along the channel margins to approximately 7.0 feet per second (2.13 meters per second) in the main channel, with an average velocity of 5.5 feet per second (1.68 meters per second) in mid-channel. The orientation of the vertically averaged velocity vectors showed flow crossing from the Illinois bank to the Missouri bank from upstream to downstream in the study area, which was confirmed by the orientation of the large dune features in mid-channel and a shift in the channel thalweg from the Illinois bank to the Missouri bank. The near-bottom velocities acquired with the acoustic Doppler current profiler ranged from 0.3 to 7.0 feet per second (0.09 to 2.13 meters per second), and the effects of the large dune features were apparent in the more random scattering of the velocity vectors, the low velocities downstream from the dunes, and higher velocities near the crests of the dunes. Despite the considerable physical complexity of this site because of the arrangement of large sand dunes in the middle of the channel, existing studies do not document persistent use of these deep, fast, main-channel habitats by pallid sturgeon. Narrow channel-margin areas on both banks having relatively low velocity, high depth slope, and high velocity gradients are similar to adult migration habitats as documented on the Missouri River downstream from Kansas City, Missouri. Although the reach generally lacks features associated with sturgeon habitat selection on the Middle Mississippi River, the barge mooring areas on the right descending bank have topographic complexity and contain large woody debris and small patches of probable gravel-cobble substrate that may have positive habitat value for sturgeon or other species. Furthermore, telemetry studies have documented sturgeon migrating upstream and downstream through this reach as adults, and they probably drift downstream through this reach as free-embryo larvae. Successful upstream migration may depend on availability of areas with hydraulic complexity and relatively low velocities, as presently exist on the margins of the site. Additionally, complexity at the channel margin may provide areas where larvae settle out from drifting in the main current or may act to slow bulk drift rates. Construction of bridge piers close to the banks will likely alter hydraulics and sediment transport on the channel margins and may result in substanti

  10. δ-Conotoxins synthesized using an acid-cleavable solubility tag approach reveal key structural determinants for NaV subtype selectivity.

    PubMed

    Peigneur, Steve; Paolini-Bertrand, Marianne; Gaertner, Hubert; Biass, Daniel; Violette, Aude; Stöcklin, Reto; Favreau, Philippe; Tytgat, Jan; Hartley, Oliver

    2014-12-19

    Conotoxins are venom peptides from cone snails with multiple disulfide bridges that provide a rigid structural scaffold. Typically acting on ion channels implicated in neurotransmission, conotoxins are of interest both as tools for pharmacological studies and as potential new medicines. δ-Conotoxins act by inhibiting inactivation of voltage-gated sodium channels (Nav). Their pharmacology has not been extensively studied because their highly hydrophobic character makes them difficult targets for chemical synthesis. Here we adopted an acid-cleavable solubility tag strategy that facilitated synthesis, purification, and directed disulfide bridge formation. Using this approach we readily produced three native δ-conotoxins from Conus consors plus two rationally designed hybrid peptides. We observed striking differences in Nav subtype selectivity across this group of compounds, which differ in primary structure at only three positions: 12, 23, and 25. Our results provide new insights into the structure-activity relationships underlying the Nav subtype selectivity of δ-conotoxins. Use of the acid-cleavable solubility tag strategy should facilitate synthesis of other hydrophobic peptides with complex disulfide bridge patterns. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Level II scour analysis for Bridge 32 (FERRTH00190032) on Town Highway 19, crossing the South Slang Little Otter Creek, Ferrisburgh, Vermont

    USGS Publications Warehouse

    Ivanoff, Michael A.; Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure FERRTH00190032 on Town Highway 19 crossing the South Slang Little Otter Creek (Hawkins Slang Brook), Ferrisburg, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Champlain section of the St. Lawrence Valley physiographic province in west-central Vermont. The 8.00-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover consists of wetlands upstream and downstream of the bridge with trees and pasture on the wide flood plains. In the study area, the South Slang Little Otter Creek has a meandering channel with essentially no channel slope, an average channel top width of 932 ft and an average bank height of 6 ft. The channel bed material ranges from clay to sand. Sieve analysis indicates that greater than 50% of the sample is coarse silt and clay and thus a medium grain size by use of sieve analysis was indeterminate. The median grain size was assumed to be a course silt with a size (D50) of 0.061mm (0.0002 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 2, 1996, indicated that the reach was stable. The Town Highway 19 crossing of the South Slang Little Otter Creek is a 45-ft-long, twolane bridge consisting of one 42-foot concrete box-beam span (Vermont Agency of Transportation, written communication, December 11, 1995). The opening length of the structure parallel to the bridge face is 41.8 ft. The bridge is supported by vertical, concrete abutments. The channel is skewed approximately 5 degrees to the opening while the opening-skew-to-roadway is zero degrees. A scour hole 3.5 ft deeper than the mean thalweg depth was observed in the upstream channel. Also a scour hole 2.0 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. The scour protection measures at the site are type-1 stone fill (less than 12 inches diameter) around the left and right abutments, along the upstream and downstream road embankments, and across the entire upstream and downstream bridge face. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 14.0 to 20.2 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 3.2 to 8.3 ft. The worst-case abutment scour occurred at the 500-year discharge. The predicted scour is well above the pile bottom elevations. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. Computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  12. Development and simulation of microfluidic Wheatstone bridge for high-precision sensor

    NASA Astrophysics Data System (ADS)

    Shipulya, N. D.; Konakov, S. A.; Krzhizhanovskaya, V. V.

    2016-08-01

    In this work we present the results of analytical modeling and 3D computer simulation of microfluidic Wheatstone bridge, which is used for high-accuracy measurements and precision instruments. We propose and simulate a new method of a bridge balancing process by changing the microchannel geometry. This process is based on the “etching in microchannel” technology we developed earlier (doi:10.1088/1742-6596/681/1/012035). Our method ensures a precise control of the flow rate and flow direction in the bridge microchannel. The advantage of our approach is the ability to work without any control valves and other active electronic systems, which are usually used for bridge balancing. The geometrical configuration of microchannels was selected based on the analytical estimations. A detailed 3D numerical model was based on Navier-Stokes equations for a laminar fluid flow at low Reynolds numbers. We investigated the behavior of the Wheatstone bridge under different process conditions; found a relation between the channel resistance and flow rate through the bridge; and calculated the pressure drop across the system under different total flow rates and viscosities. Finally, we describe a high-precision microfluidic pressure sensor that employs the Wheatstone bridge and discuss other applications in complex precision microfluidic systems.

  13. Rational design and validation of a vanilloid-sensitive TRPV2 ion channel

    PubMed Central

    Yang, Fan; Vu, Simon; Yarov-Yarovoy, Vladimir; Zheng, Jie

    2016-01-01

    Vanilloids activation of TRPV1 represents an excellent model system of ligand-gated ion channels. Recent studies using cryo-electron microcopy (cryo-EM), computational analysis, and functional quantification revealed the location of capsaicin-binding site and critical residues mediating ligand-binding and channel activation. Based on these new findings, here we have successfully introduced high-affinity binding of capsaicin and resiniferatoxin to the vanilloid-insensitive TRPV2 channel, using a rationally designed minimal set of four point mutations (F467S–S498F–L505T–Q525E, termed TRPV2_Quad). We found that binding of resiniferatoxin activates TRPV2_Quad but the ligand-induced open state is relatively unstable, whereas binding of capsaicin to TRPV2_Quad antagonizes resiniferatoxin-induced activation likely through competition for the same binding sites. Using Rosetta-based molecular docking, we observed a common structural mechanism underlying vanilloids activation of TRPV1 and TRPV2_Quad, where the ligand serves as molecular “glue” that bridges the S4–S5 linker to the S1–S4 domain to open these channels. Our analysis revealed that capsaicin failed to activate TRPV2_Quad likely due to structural constraints preventing such bridge formation. These results not only validate our current working model for capsaicin activation of TRPV1 but also should help guide the design of drug candidate compounds for this important pain sensor. PMID:27298359

  14. Level II scour analysis for Bridge 17 (NEWHTH00200017) on Town Highway 20, crossing Little Otter Creek, New Haven, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Burns, Ronda L.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure NEWHTH00200017 on Town Highway 20 crossing Little Otter Creek, New Haven, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Champlain section of the St. Lawrence Valley physiographic province in west-central Vermont. The 10.8-mi2 drainage area is in a predominantly rural and wetland basin. In the vicinity of the study site, the surface cover is shrubland on the downstream right overbank. The surface cover of the downstream left overbank, the upstream right overbank and the upstream left overbank is wetland and pasture. In the study area, Little Otter Creek has a meandering channel with a slope of approximately 0.0007 ft/ft, an average channel top width of 97 ft and an average bank height of 5 ft. The channel bed material ranges from silt and clay to cobble. Medium sized silt and clay is the channel material upstream of the approach cross-section and downstream of the exit cross-section. The median grain size (D50) of the silt and clay channel bed material is 1.52 mm (0.005 ft), which was used for contraction and abutment scour computations. From the approach cross-section, under the bridge, and to the exit cross-section, stone fill is the channel bed material. The median grain size (D50) of the stone fill channel bed material is 95.7 mm (0.314 ft). The stone fill median grain size was used solely for armoring computations. The geomorphic assessment at the time of the Level I and Level II site visit on June 11, 1996, indicated that the reach was stable.The Town Highway 20 crossing of Little Otter Creek is a 32-ft-long, two-lane bridge consisting of a 28-ft steel-beam span (Vermont Agency of Transportation, written communication, December 15, 1995). The opening length of the structure parallel to the bridge face is 24.9 ft. The bridge is supported by almost vertical, concrete abutments. The channel is skewed approximately 15 degrees to the opening while the opening-skew-toroadway is zero degrees. The scour countermeasures at the site consisted of type-1 stone fill (less than 12 inches diameter) along the left and right abutments, as well as along the upstream left and right banks. Type-2 stone fill (less than 36 inches diameter) was present along the downstream right bank. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 9.7 to 13.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.9 to 7.9 ft. Right abutment scour ranged from 10.5 to 11.8 ft. The worst-case left and right abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Water pollution risk simulation and prediction in the main canal of the South-to-North Water Transfer Project

    NASA Astrophysics Data System (ADS)

    Tang, Caihong; Yi, Yujun; Yang, Zhifeng; Cheng, Xi

    2014-11-01

    The middle route of the South-to-North Water Transfer Project (MRP) will divert water to Beijing Tuancheng Lake from Taocha in the Danjiangkou reservoir located in the Hubei province of China. The MRP is composed of a long canal and complex hydraulic structures and will transfer water in open channel areas to provide drinking water for Beijing, Shijiazhuang and other cities under extremely strict water quality requirements. A large number of vehicular accidents, occurred on the many highway bridges across the main canal would cause significant water pollution in the main canal. To ensure that water quality is maintained during the diversion process, the effects of pollutants on water quality due to sudden pollution accidents were simulated and analyzed in this paper. The MIKE11 HD module was used to calculate the hydraulic characteristics of the 42-km Xishi-to-Beijuma River channel of the MRP. Six types of hydraulic structures, including inverted siphons, gates, highway bridges, culverts and tunnels, were included in this model. Based on the hydrodynamic model, the MIKE11 AD module, which is one-dimensional advection dispersion model, was built for TP, NH3-N, CODMn and F. The validated results showed that the computed values agreed well with the measured values. In accordance with transportation data across the Dianbei Highway Bridge, the effects of traffic accidents on the bridge on water quality were analyzed. Based on simulated scenarios with three discharge rates (ranged from 12 m3/s to 17 m3/s, 40 m3/s, and 60 m3/s) and three pollution loading concentration levels (5 t, 10 t and 20 t) when trucks spill their contents (i.e., phosphate fertilizer, cyanide, oil and chromium solution) into the channel, emergency measures were proposed. Reasonable solutions to ensure the water quality with regard to the various types of pollutants were proposed, including treating polluted water, maintaining materials, and personnel reserves.

  16. Hydraulic analysis, Mad River at State Highway 41, Springfield, Ohio

    USGS Publications Warehouse

    Mayo, Ronald I.

    1977-01-01

    A hydraulic analysis of the lad River in a reach at Springfield, Ohio was made to determine the effects of relocating State Highway 41 in 1S76. The main channel was cleaned by dredging in the vicinity cf the new highway bridge and at the Detroit, Toledo and Ironton Railway bridge upstream. The new highway was placed on a high fill with relief structures for flood plain drainage consisting of a 12-foot corrugated metal pipe culvert and a bridge opening to accommodate the Detroit, Toledo and Ironton Railway and a property access road. The effect of the new highway embankment on drainage from the flood plain was requested. Also requested was the effect that might be expected on the elevation of flood waters above the new highway embankment if the access road through the new highway embankment were raised.The study indicates that the improvement in the capacity of the main channel to carry water was such that, up to a discharge equivalent to a 25-year frequency flood, the water-surface elevation in the reach upstream from the Detroit, Toledo and Ironton Railway bridge would be about 0.6 foot lower than under conditions prior to the construction on State Highway 41. Diversion through the Mad River left bank levee break above the Detroit, Toledo and Ironton Railway bridge to the flood Flain would be decreased about one-half in terms of rate of discharge in cubic feet per second. The maximum difference in elevation cf the flood water between the upstream and downstream side of the new State Highway 41 embankment would be about 0.2 foot, with an additional 0.4 foot to be expected if the access road were raised 1.5 feet.

  17. AC electric field induced dielectrophoretic assembly behavior of gold nanoparticles in a wide frequency range

    NASA Astrophysics Data System (ADS)

    Liu, Weiyu; Wang, Chunhui; Ding, Haitao; Shao, Jinyou; Ding, Yucheng

    2016-05-01

    In this work, we focus on frequency-dependence of pearl chain formations (PCF) of gold nanoparticles driven by AC dielectrophoresis (DEP), especially in a low field-frequency range, where induced double-layer charging effect at ideally polarizable surfaces on particle DEP behavior and surrounding liquid motion need not be negligible. As field frequency varies, grown features of DEP assembly structures ranging from low-frequency non-bridged gap to high-frequency single gold nanoparticle-made nanowires bridging the electrodes are demonstrated experimentally. Specifically, at 10 kHz, a kind of novel channel-like structure with parallel opposing banks is formed at the center of interelectrode gap. In stark contrast, at 1 MHz, thin PCF with diameter of 100 nm is created along the shortest distance of the isolation spacing. Moreover, a particular conductive path of nanoparticle chains is produced at 1 MHz in a DEP device embedded with multiple floating electrodes. A theoretical framework taking into account field-induced double-layer polarization at both the particle/electrolyte and electrode/electrolyte interface is developed to correlate these experimental observations with induced-charge electrokinetic (ICEK) phenomenon. And a RC circuit model is helpful in accounting for the formation of this particular non-bridged channel-like structure induced by a low-frequency AC voltage. As compared to thin PCF formed at high field frequency that effectively short circuits the electrode pair, though it is difficult for complete PCF bridging to occur at low frequency, the non-bridged conducting microstructure has potential to further miniaturize the size of electrode gap fabricated by standard micromachining process and may find useful application in biochemical sensing.

  18. Application of a sediment-transport model to estimate bridge scour at selected sites in Colorado, 1991-93

    USGS Publications Warehouse

    Vaill, J.E.

    1995-01-01

    A bridge-scour study by the U.S. Geological Survey, in cooperation with the Colorado Department of Transportation, was begun in 1991 to evaluate bridges in the State for potential scour during floods. A part of that study was to apply a computer model for sediment-transport routing to simulate channel aggradation or degradation and pier scour during floods at three bridge sites in Colorado. Stream-channel reaches upstream and downstream from the bridges were simulated using the Bridge Stream Tube model for Alluvial River Simulation (BRI-STARS). Synthetic flood hydrographs for the 500-year floods were developed for Surveyor Creek near Platner and for the Rio Grande at Wagon Wheel Gap. A part of the recorded mean daily hydrograph for the peak flow of record was used for the Yampa River near Maybell. The recorded hydrograph for the peak flow of record exceeded the computed 500-year-flood magnitude for this stream by about 22 percent. Bed-material particle-size distributions were determined from samples collected at Surveyor Creek and the Rio Grande. Existing data were used for the Yampa River. The model was used to compute a sediment-inflow hydrograph using particle-size data collected and a specified sediment-transport equation at each site. Particle sizes ranged from less than 0.5 to 16 millimeters for Surveyor Creek, less than 4 to 128 millimeters for the Yampa River, and 22.5 to 150 millimeters for the Rio Grande. Computed scour at the peak steamflows ranged from -2.32 feet at Surveyor Creek near Platner to +0.63 foot at the Rio Grande at Wagon Wheel Gap. Pier- scour depths computed at the peak streamflows ranged from 4.46 feet at the Rio Grande at Wagon Wheel Gap to 5.94 feet at the Yampa River near Maybell. The number of streamtubes used in the model varied at each site.

  19. Level II scour analysis for Bridge 51 (RANDTH00SC0051) on School Street, crossing Thayer Brook, Randolph, Vermont

    USGS Publications Warehouse

    Olson, Scott A.

    1996-01-01

    ft, an average channel top width of 36 ft and an average channel depth of 3 ft. The predominant channel bed materials are gravel and cobble (D50 is 58.2 mm or 0.191 ft). The geomorphic assessment at the time of the Level I site visits on August 4, 1994 and December 8, 1994, indicated that the reach was stable. The School Street crossing of Thayer Brook is a 39-ft-long, two-lane bridge consisting of one 35-foot concrete span (Vermont Agency of Transportation, written commun., August 2, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. Type-2 stone fill (less than 36 inches diameter) along the downstream left bank was the only existing protection. The approach channel is skewed approximately 45 degrees to the bridge face; the opening-skew-to-roadway is also 45 degrees. Additional details describing conditions at the site are included in the Level II Summary, Appendix D, and Appendix E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.0 to 2.2 ft. with the worst-case scenario occurring at the 500-year discharge. Abutment scour ranged from 6.2 to 12.0 ft. The worst-case abutment scour also occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1993, p. 48). Many factors, including historical performance during flood events, the geomorphic assessment, scour protection measures, and the results of the hydraulic analyses, must be considered to properly assess the validity of abutment scour results. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein, based on the consideration of additional contributing factors and experienced engineering judgement.

  20. Water-surface profiles of Raccoon River at Des Moines, Iowa

    USGS Publications Warehouse

    Carpenter, Philip J.; Appel, David H.

    1966-01-01

    The Raccoon River., having a drainage area of 3,630 square miles, borders the south edge of the Des Moines downtown business district before flowing into the Des Moines River at mile 201.6. A large residential area and the city airport are separated from downtown Des Moines by the Raccoon River (fig. 1). Five highway bridges and one railroad bridge span the river between the mouth and mile 205.75, the limits of this report (fig. 1). The river is confined to a narrow channel from the mouth to the Chicago, Burlington, and Quincy Railroad bridge (mile 202.6); upstream of this bridge the river is not confined and during high water spreads over a wide flood plain. Fleur Drive, a principal traffic artery to the downtown area, is the only roadway of the five that crosses this wide flood plain. It has been flooded 15 times during the period 1903, 1918-1965.

  1. Real-time seismic monitoring of the integrated cape girardeau bridge array and recorded earthquake response

    USGS Publications Warehouse

    Celebi, M.

    2006-01-01

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. The bridge was designed for a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and at surface and downhole free-field arrays of the bridge. The paper also presents the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to assess the performance of the bridge, to check design parameters, including the comparison of dynamic characteristics with actual response, and to better design future similar bridges. Preliminary analyses of ambient and low amplitude small earthquake data reveal specific response characteristics of the bridge and the free-field. There is evidence of coherent tower, cable, deck interaction that sometimes results in amplified ambient motions. Motions at the lowest tri-axial downhole accelerometers on both MO and IL sides are practically free from any feedback from the bridge. Motions at the mid-level and surface downhole accelerometers are influenced significantly by feedback due to amplified ambient motions of the bridge. Copyright ASCE 2006.

  2. Level II scour analysis for Bridge 24 (MANCUS00070024) on U.S. Route 7, crossing Lye Brook, Manchester, Vermont

    USGS Publications Warehouse

    Olson, Scott A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure MANCUS00070024 on U.S. Route 7 crossing Lye Brook, Manchester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Taconic section of the New England physiographic province in southwestern Vermont. The 8.13-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the primary surface cover consists of brush and trees. In the study area, Lye Brook has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 66 ft and an average bank height of 11 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 90.0 mm (0.295 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 6, 1996, indicated that the reach was stable. Although, the immediate reach is considered stable, upstream of the bridge the Lye Brook valley is very steep (0.05 ft/ft). Extreme events in a valley this steep may quickly reveal the instability of the channel. In the Flood Insurance Study for the Town of Manchester (Federal Emergency Management Agency, January, 1985), Lye Brook’s overbanks were described as “boulder strewn” after the August 1976 flood. The U.S. Route 7 crossing of Lye Brook is a 28-ft-long, two-lane bridge consisting of one 25-foot concrete span (Vermont Agency of Transportation, written communication, September 28, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the opening-skew-to-roadway is 55 degrees. At the time of construction, the downstream channel was relocated (written communication, Dan Landry, VTAOT, January 2, 1997). A levee on the downstream right bank was also constructed and is protected by type-4 stone-fill (less than 60 inches diameter) extending from the bridge to more than 300 feet downstream. Type-2 stone fill (less than 36 inches diameter) covers the downstream right bank from the bridge to more than 300 feet downstream. Type-2 stone-fill also extends from the bridge to 220 feet upstream on both upstream banks. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is analyzed since it has the potential of being the worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.0 to 1.6 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour computations for the left abutment ranged from 14.5 to 16.1 ft. with the worst-case occurring at the 100-year discharge. Abutment scour computations for the right abutment ranged from 6.9 to 10.4 ft. with the worst-case occurring at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  3. Level II scour analysis for Bridge 48 (FFIETH00300048) on Town Highway 30, crossing Wanzer Brook, Fairfield, Vermont

    USGS Publications Warehouse

    Flynn, Robert H.; Boehmler, Erick M.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure FFIETH00300048 on Town Highway 30 crossing Wanzer Brook, Fairfield, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in northwestern Vermont. The 6.78-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover upstream of the bridge and on the downstream right bank is primarily pasture. The downstream left bank is forested. In the study area, Wanzer Brook has an incised, straight channel with a slope of approximately 0.03 ft/ft, an average channel top width of 65 ft and an average bank height of 5 ft. The channel bed material is cobble with a median grain size (D50) of 111 mm (0.364 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 11, 1995, indicated that the reach was stable. The Town Highway 30 crossing of Wanzer Brook is a 31-ft-long, two-lane bridge consisting of one 28-foot steel-beam span (Vermont Agency of Transportation, written communication, March 8, 1995). The opening length of the structure parallel to the bridge face is 26 ft.The bridge is supported by vertical stone wall abutments with concrete caps and “kneewall” footings. The channel is skewed approximately 25 degrees to the opening while the measured opening-skew-to-roadway is 20 degrees. A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the downstream left retaining wall (extended concrete footing) during the Level I assessment. It was also observed that the right abutment is undermined with a scour depth of 0.5 ft. The scour protection at the site was limited to four large boulders (type-4, less than 60 inches diameter) along the downstream right retaining wall. The channel under the bridge is a “corduroy” log mat floor composed of 13 logs which are parallel to the bridge face and extend from 5 ft under the bridge to the downstream bridge face. The most downstream log is approximately 0.3 to 0.4 ft higher than the other logs and controls flow at lower flows. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.3 to 0.6 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 14.1 to 16.0 ft at the left abutment and from 6.8 to 7.6 ft at the right abutment. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  4. 7. DETAIL VIEW OF ROCKER ARM, SHOWING POCKETS, LUGS, INCLINED ...

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

    7. DETAIL VIEW OF ROCKER ARM, SHOWING POCKETS, LUGS, INCLINED STOPPING BLOCK AT SHOREWARD END OF TRACK GIRDER - Seddon Island Scherzer Rolling Lift Bridge, Spanning Garrison Channel from Tampa to Seddon Island, Tampa, Hillsborough County, FL

  5. Self-healing patterns in ferromagnetic-superconducting hybrids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vlasko-Vlasov, V. K.; Palacious, E.; Rosenmann, D.

    We study magnetic flux dynamic effects in a superconducting bridge with thin soft magnetic stripes placed either on top or under the bridge. Voltage-current (VI) measurements reveal that the edges of magnetic stripes oriented transvers or along the bridge introduce channels or barriers for vortex motion, resulting in the decrease or increase of the critical current, respectively. We demonstrate a remarkable self-healing effect whereby the magnetic pinning strength for the longitudinal stripes increases with current. The self-field of the current polarizes the magnetic stripes along their width, which enhances the stray fields at their edges and creates a dynamic vortexmore » pinning landscape to impede vortex flow. Our results highlight new strategies to engineer adaptive pinning topologies in superconducting-ferromagnetic hybrids.« less

  6. Bridging the gap to therapeutic strategies based on connexin/pannexin biology.

    PubMed

    Naus, Christian C; Giaume, Christian

    2016-11-29

    A unique workshop was recently held focusing on enhancing collaborations leading to identify and update the development of therapeutic strategies targeting connexin/pannexin large pore channels. Basic scientists exploring the functions of these channels in various pathologies gathered together with leading pharma companies which are targeting gap junction proteins for specific therapeutic applications. This highlights how paths of discovery research can converge with therapeutic strategies in innovative ways to enhance target identification and validation.

  7. The voltage-gated proton channel: a riddle, wrapped in a mystery, inside an enigma

    PubMed Central

    DeCoursey, Thomas E.

    2016-01-01

    The main properties of voltage gated proton channels are described, along with what is known about how the channel protein structure accomplishes these functions. Just as protons are unique among ions, proton channels are unique among ion channels. Their four transmembrane helices sense voltage, the pH gradient, and conduct protons exclusively. Selectivity is achieved by the unique ability of H3O+ to protonate an Asp-Arg salt bridge. Pathognomonic sensitivity of gating to the pH gradient ensures channel opening only when acid extrusion will result, which is crucial to most biological functions. An exception occurs in dinoflagellates in which H+ influx through HV1 triggers the bioluminescent flash. Pharmacological interventions that promise to ameliorate cancer, asthma, brain damage in ischemic stroke, Alzheimer’s disease, autoimmune diseases, and numerous other conditions, await future progress. PMID:25964989

  8. OcyKTx2, a new K⁺-channel toxin characterized from the venom of the scorpion Opisthacanthus cayaporum.

    PubMed

    Schwartz, Elisabeth F; Bartok, Adam; Schwartz, Carlos Alberto; Papp, Ferenc; Gómez-Lagunas, Froylan; Panyi, Gyorgy; Possani, Lourival D

    2013-08-01

    Opisthacanthus cayaporum belongs to the Liochelidae family, and the scorpions from this genus occur in southern Africa, Central America and South America and, therefore, can be considered a true Gondwana heritage. In this communication, the isolation, primary structure characterization, and K⁺-channel blocking activity of new peptide from this scorpion venom are reported. OcyKTx2 is a 34 amino acid long peptide with four disulfide bridges and molecular mass of 3807 Da. Electrophysiological assays conducted with pure OcyKTx2 showed that this toxin reversibly blocks Shaker B K⁺-channels with a Kd of 82 nM, and presents an even better affinity toward hKv1.3, blocking it with a Kd of ∼18 nM. OcyKTx2 shares high sequence identity with peptides belonging to subfamily 6 of α-KTxs that clustered very closely in the phylogenetic tree included here. Sequence comparison, chain length and number of disulfide bridges analysis classify OcyKTx2 into subfamily 6 of the α-KTx scorpion toxins (systematic name, α-KTx6.17). Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Bridge Crossing Simulator

    DTIC Science & Technology

    2014-10-07

    is counted as. Per the TDTC, a test bridge with longitudinal and/or lateral symmetry under non- eccentric loading can be considered as 1, 2, or 4...Level Run036 3 MLC70T (tracked) BA Run046 6 AB Run055 9 AB Run060 9 BA Run064 12 BA Run071 15 AB Run155 3 MLC96W ( wheeled ) AB...Run331 9 AB Run359 15 AB Run430 12 MLC96W ( wheeled ) BA Run434 12 AB Run447 3 BA Bank Condition: Side Slope, Even Strain Channels High

  10. Instrumentation for detailed bridge-scour measurements

    USGS Publications Warehouse

    Landers, Mark N.; Mueller, David S.; Trent, Roy E.; ,

    1993-01-01

    A portable instrumentation system is being developed to obtain channel bathymetry during floods for detailed bridge-scour measurements. Portable scour measuring systems have four components: sounding instrument, horizontal positioning instrument, deployment mechanisms, and data storage device. The sounding instrument will be a digital fathometer. Horizontal position will be measured using a range-azimuth based hydrographic survey system. The deployment mechanism designed for this system is a remote-controlled boat using a small waterplane area, twin-hull design. An on-board computer and radio will monitor the vessel instrumentation, record measured data, and telemeter data to shore.

  11. Coherent spin transfer between molecularly bridged quantum dots.

    PubMed

    Ouyang, Min; Awschalom, David D

    2003-08-22

    Femtosecond time-resolved Faraday rotation spectroscopy reveals the instantaneous transfer of spin coherence through conjugated molecular bridges spanning quantum dots of different size over a broad range of temperature. The room-temperature spin-transfer efficiency is approximately 20%, showing that conjugated molecules can be used not only as interconnections for the hierarchical assembly of functional networks but also as efficient spin channels. The results suggest that this class of structures may be useful as two-spin quantum devices operating at ambient temperatures and may offer promising opportunities for future versatile molecule-based spintronic technologies.

  12. Bridge-Scour Data Management System user's manual

    USGS Publications Warehouse

    Landers, Mark N.; Mueller, David S.; Martin, Gary R.

    1996-01-01

    The Bridge-Scour Data Management System (BSDMS) supports preparation, compilation, and analysis of bridge-scour data. The BSDMS provides interactive storage, retrieval, selection, editing, and display of bridge-scour data sets. Bridge-scour data sets include more than 200 site and measurement attributes of the channel geometry, flow hydraulics, hydrology, sediment, geomorphic-setting, location, and bridge specifications. This user's manual provides a general overview of the structure and organization of BSDMS data sets and detailed instructions to operate the program. Attributes stored by the BSDMS are described along with an illustration of the input screen where the attribute can be entered or edited. Measured scour depths can be compared with scour depths predicted by selected published equations using the BSDMS. The selected published equations available in the computational portion of the BSDMS are described. This manual is written for BSDMS, version 2.0. The data base will facilitate: (1) developing improved estimators of scour for specific regions or conditions; (2) describing scour processes; and (3) reducing risk from scour at bridges. BSDMS is available in DOS and UNIX versions. The program was written to be portable and, therefore, can be used on multiple computer platforms. Installation procedures depend on the computer platform, and specific installation instructions are distributed with the software. Sample data files and data sets of 384 pier-scour measurements from 56 bridges in 14 States are also distributed with the software.

  13. Level II scour analysis for Bridge 41 (WODSTH00750041) on Town Highway 75, crossing Happy Valley Brook, Woodstock, Vermont

    USGS Publications Warehouse

    Olson, Scott A.

    1996-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure WODSTH00750041 on town highway 75 crossing Happy Valley Brook, Woodstock, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province of east-central Vermont. The 3.45-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is brush with scattered trees. In the study area, Happy Valley Brook has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 23 ft and an average channel depth of 5 ft. The predominant channel bed materials are gravel and cobble with a median grain size (D50) of 82.8 mm (0.272 ft). The geomorphic assessment at the time of the Level II site visits on September 13, 1994 and December 14, 1994, indicated that the reach was degrading. Five logs are embedded across the channel under the bridge in an attempt to prevent further degradation (see Figures 5 and 6). The town highway 75 crossing of Happy Valley Brook is a 27-ft-long, two-lane bridge consisting of one 25-foot steel-beam span. The clear span is 17 ft. (Vermont Agency of Transportation, written communication, August 3, 1994). The bridge is supported by vertical, stone abutments with wingwalls. The channel is skewed approximately 40 degrees to the opening and the opening-skew-to-roadway is also 40 degrees. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.3 to 2.2 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 7.2 to 12.0 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  14. Level II scour analysis for Bridge 29 (CRAFTH00550029) on Town Highway 55, crossing the Black River, Craftsbury, Vermont

    USGS Publications Warehouse

    Boehmler, Erick M.; Degnan, James R.

    1996-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure CRAFTH00550029 on town highway 55 crossing the Black River, Craftsbury, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province of north-central Vermont in the town of Craftsbury. The 24.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the banks have woody vegetation coverage except for the upstream left bank and the downstream right bank, which have more brush cover than trees. In the study area, the Black River has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 41 ft and an average channel depth of 5.5 ft. The predominant channel bed material is sand and gravel (D50 is 44.7 mm or 0.147 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 7, 1995, indicated that the reach was stable. The town highway 55 crossing of the Black Riveris a 32-ft-long, one-lane bridge consisting of one 28-foot span steel stringer superstructure with a timber deck (Vermont Agency of Transportation, written communication, August 4, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 40 degrees to the opening while the opening-skew-to-roadway is 10 degrees. A scour hole 2 ft deeper than the mean thalweg depth was evident at mid-channel immediately downstream of the bridge during the Level I assessment. The only scour protection measure at the site was type-1 stone fill (less than 12 inches diameter) on the upstream right bank and road approach embankment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.9 to 1.4 ft. The worst-case contraction scour occurred at the 100-year discharge. Abutment scour ranged from 12.1 to 15.5 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Bathymetric and velocimetric surveys at highway bridges crossing the Missouri and Mississippi Rivers near St. Louis, Missouri, May 23–27, 2016

    USGS Publications Warehouse

    Huizinga, Richard J.

    2017-09-26

    Bathymetric and velocimetric data were collected by the U.S. Geological Survey, in cooperation with the Missouri Department of Transportation, near 13 bridges at 8 highway crossings of the Missouri and Mississippi Rivers in the greater St. Louis, Missouri, area from May 23 to 27, 2016. A multibeam echosounder mapping system was used to obtain channel-bed elevations for river reaches ranging from 1,640 to 1,970 feet longitudinally and extending laterally across the active channel from bank to bank during low to moderate flood flow conditions. These bathymetric surveys indicate the channel conditions at the time of the surveys and provide characteristics of scour holes that may be useful in the development of predictive guidelines or equations for scour holes. These data also may be useful to the Missouri Department of Transportation as a low to moderate flood flow comparison to help assess the bridges for stability and integrity issues with respect to bridge scour during floods.Bathymetric data were collected around every pier that was in water, except those at the edge of water, and scour holes were observed at most surveyed piers. The observed scour holes at the surveyed bridges were examined with respect to shape and depth.The frontal slope values determined for scour holes observed in the current (2016) study generally are similar to recommended values in the literature and to values determined for scour holes in previous bathymetric surveys. Several of the structures had piers that were skewed to primary approach flow, as indicated by the scour hole being longer on the side of the pier with impinging flow, and some amount of deposition on the leeward side, as typically has been observed at piers skewed to approach flow; however, at most skewed piers in the current (2016) study, the scour hole was deeper on the leeward side of the pier. At most of these piers, the angled approach flow was the result of a deflection or contraction of flow caused by a spur dike near the pier, which may affect flow differently than for a simple skew. At structure A6500 (site 33), the wide face of the pier footing and seal course would behave as a complex foundation, for which scour is computed differently.Previous bathymetric surveys exist for all the sites examined in this study. A previous survey in October 2010 at most of the sites had similar flow conditions and similar results to the 2016 surveys. A survey during flood conditions in August 2011 at the sites on the Missouri River and in May 2009 at structures A4936 and A1850 (site 35) on the Mississippi River did not always indicate more substantial scour during flood conditions. At structure A6500 (site 33) on the Mississippi River, a previous survey in 2009 was part of a habitat assessment before construction of the bridge and provides unique insight into the effects of the construction of that bridge on the channel in this reach. Substantial scour was observed near the right pier, and the riprap blanket surrounding the left pier seems to limit scour near that pier. Multiple additional surveys have been completed at structures A4936 and A1850 (site 35) on the Mississippi River, and the results of these surveys also are presented.

  16. Predicting scour in weak rock of the Oregon Coast Range : final report

    DOT National Transportation Integrated Search

    1999-10-01

    Recent experience in the Coast Range Province of Oregon demonstrates that weak sedimentary bedrock in stream channels can be vulnerable to scour. The presence of erodible rock adjacent to bridge foundations and abutments necessitates monitoring of th...

  17. 2. OVERALL VIEW OF LOWWATER DAM, LOOKING UPSTREAM. CHAIN OF ...

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

    2. OVERALL VIEW OF LOW-WATER DAM, LOOKING UPSTREAM. CHAIN OF ROCKS BRIDGE AND ST. LOUIS WATER DEPARTMENT INTAKE IN BACKGROUND, LOOKING NORTHWEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  18. High-efficiency K-band tracking antenna feed

    NASA Technical Reports Server (NTRS)

    Beavin, R. L.; Simanyi, A. I.

    1975-01-01

    Antenna feed features high aperture efficiency of multimode near-field horn and develops tracking signals without conventional monopulse bridge. Feed assembly is relatively simple and very compact. However, feed is sensitive to cross-polarized energy which couples into orthogonal error channel.

  19. Hydraulic and Geomorphic Assessment of the Merced River and Historic Bridges in Eastern Yosemite Valley, Yosemite National Park, California: Sacramento, California

    USGS Publications Warehouse

    Minear, J. Toby; Wright, Scott A.

    2013-01-01

    The Merced River in the popular and picturesque eastern-most part of Yosemite Valley in Yosemite National Park, California, USA, has been extensively altered since the park was first conceived in 1864. Historical human trampling of streambanks has been suggested as the cause of substantial increases in stream width, and the construction of undersized stone bridges in the 1920s has been suggested as the major factor leading to an increase in overbank flooding due to deposition of bars and islands between the bridges. In response, the National Park Service at Yosemite National Park (YNP) requested a study of the hydraulic and geomorphic conditions affecting the most-heavily influenced part of the river, a 2.4-km reach in eastern Yosemite Valley extending from above the Tenaya Creek and Merced River confluence to below Housekeeping Bridge. As part of the study, present-day conditions were compared to historical conditions and several possible planning scenarios were investigated, including the removal of an elevated road berm and the removal of three undersized historic stone bridges identified by YNP as potential problems: Sugar Pine, Ahwahnee and Stoneman Bridges. This Open-File Report will be superseded at a later date by a Scientific Investigations Report. A two-dimensional hydrodynamic model, the USGS FaSTMECH (Flow and Sediment Transport with Morphological Evolution of Channels) model, within the USGS International River Interface Cooperative (iRIC) model framework, was used to compare the scenarios over a range of discharges with annual exceedance probabilities of 50-, 20-, 10-, and 5- percent. A variety of topographic and hydraulic data sources were used to create the input conditions to the hydrodynamic model, including aerial LiDAR (Light Detection And Ranging), ground-based LiDAR, total station survey data, and grain size data from pebble counts. A digitized version of a historical topographic map created by the USGS in 1919, combined with estimates of grain size, was used to simulate historical conditions, and the planning scenarios were developed by altering the present-day topography. Roughness was estimated independently of measured water-surface elevations by using the mapped grain-size data and the Keulegan relation of grain size to drag coefficient. The FaSTMECH hydrodynamic model was evaluated against measured water levels by using a 130.9 m3 s-1 flow (approximately a 33-percent annual exceedance probability flood) with 36 water-surface elevations measured by YNP personnel on June 8, 2010. This evaluation run had a root mean square error of 0.21 m between the simulated- and observed water-surface elevations (less than 10 percent of depth), though the observed water-surface elevations had relatively high variation due to the strong diurnal stage changes over the course of the 4.4-hour collection period, during which discharge varied by about 15 percent. There are presently no velocity data with which to test the model. A geomorphic assessment was performed that consisted of an estimate of the magnitude and frequency of bedload and suspended-sediment transport at “Tenaya Bar”, an important gravel-cobble bar located near the upstream end of the study site that determines the amount of flow across the floodplain at the Sugar Pine – Ahwahnee bend. An analysis of select repeat cross-sections collected by YNP since the late 1980s was done to investigate changes in channel cross-sectional area near the Tenaya Bar site. The results of the FaSTMECH models indicate that the maximum velocities in the present-day channel within the study reach are associated with Stoneman and Sugar Pine Bridges, at close to 3.0 m s-1 for the 5-percent annual exceedance probability flood. The modeled maximum velocities at Ahwahnee Bridge are comparatively low, at between 1.5 and 2.0 m s-1, most likely due to the bridge's orientation parallel to down-valley floodplain flows. The results of the FaSTMECH models for the bridge removal scenarios indicate a reduction in average velocity at the bridge sites for the range of flows by approximately 23-38 percent (Sugar Pine Bridge), 32-42 percent (Ahwahnee Bridge), and 33-39 percent (Stoneman Bridge), though a side channel of concern to YNP management did not appear to be substantially affected by the removal scenarios. In comparison to the historical data, the FaSTMECH results suggest that flows for present-day conditions do not inundate the floodplain until between the 50- and 20-percent annual exceedance probability flood, whereas historically, a large portion of the floodplain was inundated during the 50-percent annual exceedance probability flood. Modeled maximum velocities in the present-day channel commonly exceed 2.0 m s-1, whereas with the historical scenario, modeled maximum in-channel velocities rarely exceeded 2.0 m s-1. The geomorphic analysis of the magnitude-frequency of bedload and suspended-sediment transport suggests that at the important Tenaya Bar site, the majority of bed sediment is mobile during most snowmelt-dominated floods. In contrast to sediment transport capacity, the analysis of repeat cross-sections suggests that bedload sediment supply into the eastern Yosemite Valley may be quite different between rain-on-snow floods and snowmelt-dominated floods, potentially with most sediment supply occurring during rain-on-snow floods, such as the 1997 flood. In contrast, the magnitude-frequency analysis of bedload and suspended-sediment transport suggests that long-term bedload sediment transport is likely dominated by snowmelt floods, and suspended-sediment transport is relatively low compared to bedload transport. Obtaining measured velocity data throughout the study reach would aid in model calibration, and thus would improve confidence in model results. Improved confidence in the model velocity results would allow additional substantial analyses of reach-scale effects of the planning scenarios and would enable the development of geomorphic models to evaluate the long-term geomorphic responses of the site. In addition, the collection of watershed sediment-supply data, about which little is presently known, would give planners helpful tools to plan restoration scenarios for this nationally important river.

  20. Earth Observations taken by the Expedition 10 crew

    NASA Image and Video Library

    2004-10-25

    ISS010-E-05070 (25 October 2004) --- Corrientes, Argentina, and the Parana River are featured in this image photographed by an Expedition 10 crewmember on the International Space Station (ISS). Corrientes, Argentina sits on the east bank of the Parana River, South America’s third largest river (after the Negro and Amazon Rivers). From its headwaters in southeastern Brazil, the river flows southwestward around southern Paraguay, and then into Argentina. Corrientes is located just inside Argentina, across the river from the southwestern tip of Paraguay. The bridge over the Parana, built in the 1970s, connects Corrientes to its sister city, Resistencia, (beyond the left edge of image) on the western bank of the river. Sun glint on the river gives it a silvery glow and emphasizes channel islands in the river, side channels, and meander scars on the floodplain opposite the city, and even reveals the pattern of disturbed flow downstream of the bridge pylons. The old part of the city appears as a zone of smaller, more densely clustered city blocks along the river to the north of a major highway, which runs through Corrientes from the General Belgrano Bridge to the northeast (upper right of image). Larger blocks of the younger cityscape, with more green space, surround these core neighborhoods.

  1. Level II scour analysis for Bridge 45a (BRIDUS00040045a) on U.S. Route 4, crossing Ottauquechee River, Bridgewater, Vermont

    USGS Publications Warehouse

    Olson, Scott A.

    1996-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure BRIDUS00040045a on U.S.. Route 4 crossing the Ottauquechee River, Bridgewater, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge available from VTAOT files was compiled prior to conducting Level I and Level II analyses and can be found in Appendix D. The site is in the Green Mountain physiographic province of central Vermont in the town of Bridgewater. The 72.1-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the overbank areas are lawn or pasture with a few residences. The immediate channel banks have moderately dense woody vegetation. In the study area, the Ottauquechee River has a sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 81 ft and an average channel depth of 3 ft. The predominant channel bed materials are gravel and cobble (D50 is 54.9 mm or 0.180 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 26, 1994, indicated that the reach was stable. The U.S. Route 4 crossing of the Ottauquechee Riveris a 172-ft-long, two-lane bridge consisting of three steel-beam spans supported by spill-through abutments and two concrete piers (Vermont Agency of Transportation, written commun., August 25, 1994). The abutment and road approaches are protected by type-2 stone fill (less than 36 inches diameter). The North Branch of the Ottauquechee River joins the Ottauquechee River approximately 200 feet upstream of the bridge on the main branch’s left bank. The channel approach to the bridge has a mild bend with the bridge skewed 15 degrees to flow; the opening-skew-to-roadway is 30 degrees. Additional details describing conditions at the site are included in the Level II Summary, Appendix D, and Appendix E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 3.1 to 4.0 ft. with the worst-case contraction scour occurring at the 500-year and incipient road-overflow discharges. Abutment scour ranged from 9.3 to 15.2 ft. The worst-case abutment scour also occurred at the 500-year discharge. Pier scour ranged from 11.4 to 12.4 ft. with the worst-case scenario occurring at the incipient roadway overflow discharge. The incipient roadway overflow discharge was between the 100- and 500-year discharges. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1993, p. 48). Many factors, including historical performance during flood events, the geomorphic assessment, scour protection measures, and the results of the hydraulic analyses, must be considered to properly assess the validity of abutment scour results. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein, based on the consideration of additional contributing factors and experienced engineering judgement.

  2. Level II scour analysis for Bridge 3 (EASTTH00010003) on Town Highway 1, crossing the East Branch Passumpsic River, East Haven, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Boehmler, Erick M.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure EASTTH00010003 on Town Highway 1 crossing the East Branch Passumpsic River, East Haven, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the White Mountain section of the New England physiographic province in northeastern Vermont. The 50.4-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover on the left bank upstream is forest. On the remaining three banks the surface cover is pasture while the immediate banks have dense woody vegetation. In the study area, the East Branch Passumpsic River has an incised, sinuous channel with a slope of approximately 0.003 ft/ft, an average channel top width of 62 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 61.5 mm (0.187 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 14, 1995, indicated that the reach was stable. The Town Highway 1 crossing of the East Branch Passumpsic River is a 89-ft-long, two-lane bridge consisting of one 87-foot steel-beam span (Vermont Agency of Transportation, written communication, March 17, 1995). The opening length of the structure parallel to the bridge face is 84.7 ft. The bridge is supported by vertical, concrete abutments with sloped stone fill in front that creates a spill through embankment. The channel is skewed approximately zero degrees to the opening and the opening-skew-to-roadway is also zero degrees. Channel scour 0.5 ft deeper than the mean thalweg depth was observed to the left of the center of the channel under the bridge during the Level I assessment. The scour countermeasures at the site are type-2 stone fill (less than 36 inches diameter) along the downstream left bank and type-4 stone fill (less than 60 inches diameter) in front of the abutments creating spill through slopes. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0 to 1.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.4 to 11.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  3. Level II scour analysis for Bridge 38 (TOPSTH00570038) on Town Highway 57, crossing Waits River, Topsham, Vermont

    USGS Publications Warehouse

    Striker, Lora K.; Boehmler, Erick M.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure TOPSTH00570038 on Town Highway 57 crossing the Waits River, Topsham, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in east central Vermont. The 37.3-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is predominantly pasture while the left bank upstream is suburban. In the study area, the Waits River has a sinuous locally anabranched channel with a slope of approximately 0.01 ft/ft, an average channel top width of 76 ft and an average bank height of 6 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 57.2 mm (0.188 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 28, 1995, indicated that the reach was considered laterally unstable due to cut-banks upstream, mid-channel bars and lateral migration of the channel towards the left abutment. The Town Highway 34 crossing of the Waits River is a 34-ft-long, one-lane bridge consisting of one 31-foot steel-beam span (Vermont Agency of Transportation, written communication, March 28, 1995). The opening length of the structure parallel to the bridge face is 30.4 ft. The bridge is supported by a vertical, stone abutment with concrete facing and wingwalls on the right and by a vertical, concrete abutment with wingwalls on the left. The channel is skewed approximately 0 degrees to the opening and the opening-skew-to-roadway is also zero degrees. A scour hole 2.0 ft deeper than the mean thalweg depth was observed towards the left bank underneath the bridge. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the left bank upstream, in the upstream left wing wall area, along the left abutment, at the downstream end of the right abutment, and in the downstream left wing wall area. There is type-3 stone fill (less than 48 inches diameter) in the downstream right wing wall area. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.6 to 5.2 ft. The worst-case contraction scour occurred at the 100-year discharge. Abutment scour ranged from 9.8 to 18.5 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  4. Level II scour analysis for Bridge 41 (ROCKTH00390041) on Town Highway 39, crossing the Saxtons River, Rockingham, Vermont

    USGS Publications Warehouse

    Boehmler, Erick M.; Degnan, James R.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ROCKTH00390041 on Town Highway 39 crossing the Saxtons River, Rockingham, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 57.4-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover consists of forest on the left bank and pasture with some trees on the right bank. In the study area, the Saxtons River has an sinuous channel with a slope of approximately 0.009 ft/ft, an average channel top width of 112 ft and an average bank height of 10 ft. The channel bed material ranges from sand to cobbles with a median grain size (D50) of 103 mm (0.339 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 15, 1996, indicated that the reach was laterally unstable. There are wide point bars, cut-banks with fallen trees, and areas of localized channel scour along the left bank, where there is bedrock exposure at the surface. The Town Highway 39 crossing of the Saxtons River is an 85-ft-long, one-lane bridge consisting of one 82-foot steel-beam span (Vermont Agency of Transportation, written communication, March 31, 1995). The bridge is supported by vertical, concrete abutments without wingwalls. The channel is skewed approximately 30 degrees to the opening while the opening-skew-to-roadway is zero degrees. A scour hole 3 ft deeper than the mean thalweg depth was observed during the Level I assessment along the left side of the channel under the bridge exposing the left abutment footing 5.5 feet. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) on the left banks upstream and downstream and the left abutment wall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 2.2 to 3.8 feet. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 21.4 to 23.2 feet and 26.2 to 32.4 feet at the left and right abutments respectively. The worst-case abutment scour occurred for the right abutment at the incipient overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Bedrock was exposed at the surface in some areas of the channel and potentially is located at a shallower depth than the scour depths indicated above. Nevertheless, scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  5. 14. Photocopy of drawing (this photograph is an 8''x 10'' ...

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

    14. Photocopy of drawing (this photograph is an 8''x 10'' contact print; November 1, 1993 revision of a May, 1982 as built drawing by M. Villafane, in possession of the Highway System Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Perdomo Channel, Road no. P.R.2, Km. 75.60, Arecibo, P.R. no. 2 of 3. - Puente del Cano Perdomo, Route PR-2 spanning Cano Perdomo Channel, Arecibo, Arecibo Municipio, PR

  6. 15. Photocopy of drawing (this photograph is an 8''x 10'' ...

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

    15. Photocopy of drawing (this photograph is an 8''x 10'' contact print; November 1, 1993 revision of a May, 1982 as built drawing by M. Villafane, in possession of the Highway System Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Perdomo Channel, Road no. P.R.2, Km. 75.60, Arecibo, P.R. no. 3 of 3. - Puente del Cano Perdomo, Route PR-2 spanning Cano Perdomo Channel, Arecibo, Arecibo Municipio, PR

  7. 13. Photocopy of drawing (this photograph is an 8''x 10'' ...

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

    13. Photocopy of drawing (this photograph is an 8''x 10'' contact print; November 1, 1993 revision of a May, 1982 as built drawing by M. Villafane, in possession of the Highway System Administration Office of the Puerto Rico Highway and Transportation Authority) Bridge over Perdomo Channel, Road no. P.R.2, Km. 75.60, Arecibo, P.R. no. 1 of 3. - Puente del Cano Perdomo, Route PR-2 spanning Cano Perdomo Channel, Arecibo, Arecibo Municipio, PR

  8. 33 CFR 165.814 - Security Zones; Captain of the Port Houston-Galveston Zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Ship Channel Light 133 (LLNR-24450) west to the T & N Rail Road Swing Bridge at the entrance to Buffalo...°59′12″ W (LLNR-23525), and Houston Ship Channel Light 91, 29°41′00″ N, 94°59′00″ W (LLNR-23375) (NAD...°23′16″ N, 94°53′15″ W (NAD 1983). (5) Freeport, Texas. (i) The Dow Barge Canal, containing all waters...

  9. 33 CFR 165.814 - Security Zones; Captain of the Port Houston-Galveston Zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Ship Channel Light 133 (LLNR-24450) west to the T & N Rail Road Swing Bridge at the entrance to Buffalo...°59′12″ W (LLNR-23525), and Houston Ship Channel Light 91, 29°41′00″ N, 94°59′00″ W (LLNR-23375) (NAD...°23′16″ N, 94°53′15″ W (NAD 1983). (5) Freeport, Texas. (i) The Dow Barge Canal, containing all waters...

  10. 33 CFR 165.814 - Security Zones; Captain of the Port Houston-Galveston Zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Ship Channel Light 133 (LLNR-24450) west to the T & N Rail Road Swing Bridge at the entrance to Buffalo...°59′12″ W (LLNR-23525), and Houston Ship Channel Light 91, 29°41′00″ N, 94°59′00″ W (LLNR-23375) (NAD...°23′16″ N, 94°53′15″ W (NAD 1983). (5) Freeport, Texas. (i) The Dow Barge Canal, containing all waters...

  11. 33 CFR 165.814 - Security Zones; Captain of the Port Houston-Galveston Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Ship Channel Light 133 (LLNR-24450) west to the T & N Rail Road Swing Bridge at the entrance to Buffalo...°59′12″ W (LLNR-23525), and Houston Ship Channel Light 91, 29°41′00″ N, 94°59′00″ W (LLNR-23375) (NAD...°23′16″ N, 94°53′15″ W (NAD 1983). (5) Freeport, Texas. (i) The Dow Barge Canal, containing all waters...

  12. Level II scour analysis for Bridge 42 (HARDELMSTR0042) on Elm Street, crossing Cooper Brook, Hardwick, Vermont

    USGS Publications Warehouse

    Olson, Scott A.

    1996-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure HARDELMSTR0042 on Elm Street crossing Cooper Brook, Hardwick, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in north-central Vermont. The 16.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the overbanks are primarily grass covered with some brush along the immediate channel banks except the upstream right bank and overbank which is forested and the downstream left overbank which has a lumberyard. In the study area, Cooper Brook has a sinuous channel with a slope of approximately 0.005 ft/ft, an average channel top width of 50 ft and an average channel depth of 6 ft. The predominant channel bed materials are sand and gravel with a median grain size (D50) of 1.25 mm (0.00409 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 24, 1995, indicated that the reach was stable. The Elm Street crossing of Cooper Brook is a 39-ft-long, two-lane bridge consisting of one 37-foot concrete span (Vermont Agency of Transportation, written communication, March 17, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 40 degrees to the opening while the opening-skew-to-roadway is 45 degrees. On August 17, 1995 the site was revisited to investigate the effect of the August 4-5, 1995 flood on the structure. Channel features such as scour holes and point bars were shifted by the high flow event. Details of these changes can be found in the Level I data form in Appendix E. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and G. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 3.4 ft. The worst-case contraction scour occurred at the incipient-overtopping discharge which was less than the 100-year discharge. Abutment scour ranged from 7.1 to 10.4 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1993, p. 48). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  13. Level II scour analysis for Bridge 25 (JAMATH00010025) on Town Highway 1, crossing Ball Mountain Brook, Jamaica, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure JAMATH00010025 on Town Highway 1 crossing Ball Mountain Brook, Jamaica, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in southern Vermont. The 29.5-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest except on the downstream right bank which is pasture with some trees along the channel. In the study area, Ball Mountain Brook has an incised, straight channel with a slope of approximately 0.021 ft/ft, an average channel top width of 86 ft and an average bank height of 9 ft. The channel bed material ranges from gravel to bedrock with a median grain size (D50) of 222 mm (0.727 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 13, 1996, indicated that the reach was stable. The Town Highway 1 crossing of Ball Mountain Brook is a 78-ft-long, two-lane bridge consisting of one 75-foot steel-beam span (Vermont Agency of Transportation, written communication, March 29, 1995). The opening length of the structure parallel to the bridge face is 73 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 30 degrees to the opening while the opening-skew-to-roadway is 30 degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed at the upstream bridge face. The scour protection measures at the site were type-2 stone fill (less than 36 inches diameter) along the upstream banks and along both abutments, and type-3 stone fill (less than 48 inches diameter) along the downstream banks. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour only occurred at the 500-year discharge and was 0.1 ft. Abutment scour ranged from 11.2 to 15.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  14. Level II scour analysis for Bridge 35, (ANDOVT00110035) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ANDOVT00110035 on State Route 11 crossing the Middle Branch Williams River, Andover, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (Federal Highway Administration, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in south-central Vermont. The 4.65-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the left bank and small trees and brush on the right bank upstream and downstream of the bridge. In the study area, the Middle Branch Williams River has an incised, meandering channel with a slope of approximately 0.02 ft/ft, an average channel top width of 57 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 31.4 mm (0.103 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 28, 1996, indicated that the reach was laterally unstable. There are cut-banks upstream and downstream of the bridge and an island in the channel upstream. The State Route 11 crossing of the Middle Branch Williams River is a 28-ft-long, two-lane bridge consisting of one 24-ft concrete tee-beam span (Vermont Agency of Transportation, written communication, March 28, 1995). The opening length of the structure parallel to the bridge face is 23.6 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the computed opening-skew-to-roadway is 25 degrees. A scour hole ranging from 1.5 to 1.75 ft deeper than the mean thalweg depth was observed along the upstream left wingwall, the left abutment, and the downstream left wingwall during the Level I assessment. The scour countermeasures at the site included type-1 stone fill (less than 12 inches diameter) at the right road approach upstream and downstream of the bridge and type-2 stone fill (less than 36 inches diameter) at the left road approach upstream and downstream of the bridge. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 2.0 to 4.3 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 14.4 to 16.5 ft at the left abutment and from 6.3 to 8.8 ft at the right abutment. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Value engineering and cost effectiveness of various fiber reinforced polymer (FRP) repair systems.

    DOT National Transportation Integrated Search

    2006-06-01

    Seventeen 40 year old C-Channel type prestressed concrete bridge girders and one impact damaged AASHTO : Type II prestressed concrete girder were tested under static and fatigue loading to determine the cost-effectiveness : and value engineering aspe...

  16. 22. Detail of remnants of winch and motor on remains ...

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

    22. Detail of remnants of winch and motor on remains of machinery house platform east of drawspan; note cables (still connected to drawspan) coming off the winding drum; view to north. - Summer Street Bridge, Spanning Reserved Channel, Boston, Suffolk County, MA

  17. 4. DETAIL VIEW OF ROCKFILL SECTION OF LOWWATER DAM, LOOKING ...

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

    4. DETAIL VIEW OF ROCKFILL SECTION OF LOW-WATER DAM, LOOKING NORTHEAST (UPSTREAM). CHAIN OF ROCKS BRIDGE AND ST. LOUIS WATER DEPARTMENT INTAKES IN BACKGROUND - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  18. Implications of Metaphors in Defining Technical Communication.

    ERIC Educational Resources Information Center

    Beck, Charles E.

    1991-01-01

    Identifies four metaphors that appear dominant in current studies in the field of technical communication: transmitter, channel, balance, and bridge. Suggests limitations upon each of the metaphors. Discusses the alternative metaphors of lock, translator, transformer, synthesizer, conductor, and orchestrator. Proposes orchestration as a fruitful…

  19. Assuring the Economic Health of America's Cities.

    ERIC Educational Resources Information Center

    Cisneros, Henry G.

    1982-01-01

    Discusses the relationship of the economic conditions of cities to the national economy. A national urban policy is needed which would promote cooperation between business and government, increase investment in public facilities--roads, bridges, ports, etc.--and channel more resources to local governments. (AM)

  20. Developing a National Stream Morphology Data Exchange: Needs, Challenges, and Opportunities.

    EPA Science Inventory

    Stream morphology data, primarily consisting of channel and foodplain geometry and bed material size measurements, historically have had a wide range of applications and uses including culvert/ bridge design, rainfall- runoff modeling, food inundation mapping (e.g., U.S. Federal ...

  1. Assessment of bridge scour in the lower, middle, and upper Yangtze River estuary with riverbed sonar profiling techniques.

    PubMed

    Zheng, Shuwei; Xu, Y Jun; Cheng, Heqin; Wang, Bo; Lu, Xuejun

    2017-12-12

    Riverbed scour of bridge piers can cause rapid loss in foundation strength, leading to sudden bridge collapse. This study used multi-beam echo sounders (Seabat 7125) to map riverbed surrounding the foundations of four major bridges in the lower, middle, and upper reaches of the 700-km Yangtze River Estuary (YRE) during June 2015 and September 2016. The high-resolution data were utilized to analyze the morphology of the bridge scour and the deformation of the wide-area riverbed (i.e., 5-18 km long and 1.3-8.3 km wide). In addition, previous bathymetric measurements collected in 1998, 2009, and 2013 were used to determine riverbed erosion and deposition at the bridge reaches. Our study shows that the scour depth surrounding the bridge foundations progressed up to 4.4-19.0 m in the YRE. Over the past 5-15 years, the total channel erosion in some river reaches was up to 15-17 m, possessing a threat to the bridge safety in the YRE. Tide cycles seemed to have resulted in significant variation in the scour morphology in the lower and middle YRE. In the lower YRE, the riverbed morphology displayed one long erosional ditch on both sides of the bridge foundations and a long-strip siltation area distributed upstream and downstream of the bridge foundations; in the middle YRE, the riverbed morphology only showed erosional morphology surrounding the bridge foundations. Large dunes caused deep cuts and steeper contours in the bridge scour. Furthermore, this study demonstrates that the high-resolution grid model formed by point cloud data of multi-beam echo sounders can clearly display the morphology of the bridge scour in terms of wide areas and that the sonar technique is a very useful tool in the assessment of bridge scours.

  2. 31. Closeup view of the electrical and mechanical rail connections ...

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

    31. Closeup view of the electrical and mechanical rail connections between the two spans facing north; 'pins' and electrical connection. Both spans are down and locked. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  3. 30 CFR 816.151 - Primary roads.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., or greater event as specified by the regulatory authority; (2) Drainage pipes and culverts shall be... drainage over the road surface and embankment; (4) Culverts shall be installed and maintained to sustain... intermittent stream channel crossings shall be made using bridges, culverts, low-water crossings, or other...

  4. 30 CFR 816.151 - Primary roads.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., or greater event as specified by the regulatory authority; (2) Drainage pipes and culverts shall be... drainage over the road surface and embankment; (4) Culverts shall be installed and maintained to sustain... intermittent stream channel crossings shall be made using bridges, culverts, low-water crossings, or other...

  5. 30 CFR 816.151 - Primary roads.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., or greater event as specified by the regulatory authority; (2) Drainage pipes and culverts shall be... drainage over the road surface and embankment; (4) Culverts shall be installed and maintained to sustain... intermittent stream channel crossings shall be made using bridges, culverts, low-water crossings, or other...

  6. Conversational Agents in Virtual Worlds: Bridging Disciplines

    ERIC Educational Resources Information Center

    Veletsianos, George; Heller, Robert; Overmyer, Scott; Procter, Mike

    2010-01-01

    This paper examines the effective deployment of conversational agents in virtual worlds from the perspective of researchers/practitioners in cognitive psychology, computing science, learning technologies and engineering. From a cognitive perspective, the major challenge lies in the coordination and management of the various channels of information…

  7. 17. Detail view southwest showing brick parapet, wood entablature, brick ...

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

    17. Detail view southwest showing brick parapet, wood entablature, brick pilasters with molded wood caps, splayed arch and arched window lintels of north elevation of west operator's house. - Yellow Mill Bridge, Spanning Yellow Mill Channel at Stratford Avenue, Bridgeport, Fairfield County, CT

  8. View of approach span and movable span, looking southeast from ...

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

    View of approach span and movable span, looking southeast from navy land. Note that navigational channel exists only on north side of movable span. - Naval Supply Annex Stockton, Daggett Road Bridge, Daggett Road traversing Burns Cut Off, Stockton, San Joaquin County, CA

  9. Design of high-energy high-current linac with focusing by superconducting solenoids

    NASA Astrophysics Data System (ADS)

    Batskikh, Guennady I.; Belugin, Vladimir M.; Bondarev, Boris I.; Fedotov, Arkady P.; Durkin, Alexander P.; Ivanov, Yury D.; Mikhailov, Vladimir N.; Murin, Boris P.; Mustafin, Kharis Kh.; Shumakov, Igor V.; Uksusov, Nikolay I.

    1995-09-01

    The advancement of MRTI design for 1.5 GeV and 250 mA ion CW linac is presented in the report. In new linac version all the way from input to output the ions are focused by magnetic fields of superconducting solenoids. The ion limit current is far beyond the needed value. The linac focusing channel offers major advantages over the more conventional ones. The acceptance is 1.7 times as large for such focusing channel as for quadrupole one. Concurrently, a random perturbation sensitivity for such channel is one order of magnitude smaller than in quadrupole channel. These focusing channel features allow to decrease beam matched radius and increase a linac radiation purity without aperture growth. ``Regotron'' is used as high power generator in linac main part. But D&W cavities need not be divided into sections connected by RF-bridges which denuded them of high coupling factor.

  10. Bridging the divide between science and journalism.

    PubMed

    Van Eperen, Laura; Marincola, Francesco M; Strohm, Jennifer

    2010-03-10

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media.Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

  11. Bridging the Divide between Science and Journalism

    PubMed Central

    2010-01-01

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings. PMID:20219123

  12. Level II scour analysis for Bridge 46 (LINCTH00060046) on Town Highway 6, crossing the New Haven River, Lincoln, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure LINCTH00060046 on Town Highway 6 crossing the New Haven River, Lincoln, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in west-central Vermont. The 45.9-mi2 drainage area is in a predominantly suburban and forested basin. In the vicinity of the study site, the surface cover is forest upstream of the bridge. The downstream right overbank near the bridge is suburban with buildings, homes, lawns, and pavement (less than fifty percent). The downstream left overbank is brushland while the immediate banks have dense woody vegetation. In the study area, the New Haven River has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 95 ft and an average bank height of 7 ft. The channel bed material ranges from sand to bedrock with a median grain size (D50) of 120.7 mm (0.396 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 13, 1996, indicated that the reach was stable. The Town Highway 34 crossing of the New Haven River is a 85-ft-long, two-lane bridge consisting of an 80-foot steel arch truss (Vermont Agency of Transportation, written communication, December 14, 1995). The opening length of the structure parallel to the bridge face is 69 feet. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 25 degrees to the opening while the opening-skew-to-roadway is 5 degrees. A scour hole 2.0 ft deeper than the mean thalweg depth was observed in the downstream channel during the Level I assessment. Protection measures at the site include type-1 stone fill (less than 12 inches diameter) at the upstream left wingwall, type-2 stone fill (less than 36 inches diameter) at the downstream end of the downstream left wingwall, and type-3 stone fill (less than 48 inches diameter) at the upstream right wingwall and the downstream end of the downstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 1.7 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge. Left abutment scour ranged from 12.9 to 17.8 ft. Right abutment scour ranged from 5.9 to 11.9 ft. The worst-case abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  13. Level II scour analysis for Bridge 28 (STRATH00020028) on Town Highway 2, crossing the West Branch Ompompanoosuc River, Strafford, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure STRATH00020028 on Town Highway 2 crossing the West Branch Ompompanoosuc River, Strafford, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gathered from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in central Vermont. The 25.4-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge. In the study area, the West Branch Ompompanoosuc River has a sinuous channel with a slope of approximately 0.002 ft/ft, an average channel top width of 34 ft and an average bank height of 6 ft. The channel bed material ranges from silt and clay to cobbles with a median grain size (D50) of 20.4 mm (0.0669 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 24, 1996, indicated that the reach was laterally unstable, because of moderate fluvial erosion. The Town Highway 2 crossing of the West Branch Ompompanoosuc River is a 31-ft-long, twolane bridge consisting of a 26-foot concrete tee-beam span (Vermont Agency of Transportation, written communication, October 23, 1995). The opening length of the structure parallel to the bridge face is 24.6 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the computed opening-skew-toroadway is 5 degrees. A scour hole 3.2 ft deeper than the mean thalweg depth was observed under the bridge along the right side of the channel during the Level I assessment. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the upstream right bank, the upstream right wingwall, the right abutment and the downstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 3.2 to 4.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 4.4 to 7.5 ft. Right abutment scour ranged from 7.2 to 10.1 ft.The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  14. Level II scour analysis for Bridge 29 (HUNTTH00290029) on Town Highway 29, crossing Cobb Brook, Huntington, Vermont

    USGS Publications Warehouse

    Flynn, Robert H.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure HUNTTH00290029 on Town Highway 29 crossing Cobb Brook, Huntington, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in northwestern Vermont. The 4.16-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream and downstream of the bridge. In the study area, Cobb Brook has an incised, straight channel with a slope of approximately 0.024 ft/ft, an average channel top width of 53 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to bedrock with a median grain size (D50) of 112.0 mm (0.367 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 25, 1996, indicated that the reach was stable. The Town Highway 29 crossing of Cobb Brook is a 36-ft-long, one-lane bridge consisting of one 30-foot steel-beam span (Vermont Agency of Transportation, written communication, December 11, 1995) and a wooden deck. The opening length of the structure parallel to the bridge face is 27 ft.The bridge is supported by vertical, concrete abutments. The channel is skewed approximately 25 degrees to the opening while the opening-skew-to-roadway was measured to be 20 degrees. VTAOT records indicate an opening-skew-to-roadway of zero degrees. A scour hole 1.5 ft deeper than the mean thalweg depth was observed extending from 12 ft upstream of the upstream end of the left abutment to 10 ft under the bridge in the center of the channel during the Level I assessment. Another scour hole approximately 1.2 ft deeper than the mean thalweg depth was observed along the downstream end of the right abutment during the Level I assessment. The scour protection measures at the site included type-2 stone fill (less than 36 inches diameter) along the upstream end of the right abutment and type-3 stone fill (less than 48 inches diameter) along the upstream end of the upstream left retaining wall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was computed to be zero ft. Abutment scour ranged from 9.9 to 12.5 ft along the left abutment and from 6.2 to 8.6 ft along the right abutment. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Stability of aggregates in the environment: role of solid bridging

    NASA Astrophysics Data System (ADS)

    Seiphoori, A.; Jerolmack, D. J.; Arratia, P. E.

    2017-12-01

    Colloids in suspension may form larger flocs under favorable conditions, via diffusion- or reaction-limited aggregation. In addition, the process of drying colloidal suspensions drives colloids together via hydrodynamic forces to form aggregates, that may be stable or unstable when subject to re-wetting and transport. Channel banks, shorelines and hillslopes are examples where the periodic wetting and drying results in the aggregation of muds. If aggregates disperse, the mud structure is unstable to subsequent wetting or fluid shear and can easily be detached and transported to rivers and coasts. The effective friction that governs hillslope and channel-bank soil creep rates also depends on the stability of the soil aggregates. Yet, few studies probe the particle-scale assembly or stability of aggregates subject to environmental loads, and the effects of shape or size heterogeneity have not been examined in detail. Here we investigate the formation and stability of aggregates subject to passive re-wetting (by misting) and shearing using a simple Poiseuille flow in a microfluidic device. We study the kinetics of a wide range of silicate colloids of different size and surface charge properties using in situ microscopy and particle tracking. We find that negatively charged silica microspheres are dragged by the retreating edge of an evaporating drop and are resuspended easily on re-wetting, showing that aggregates are unstable. In contrast, a bi-disperse suspension created by the addition of silica nanoparticles forms stable deposits, where nanoparticles bind larger particles by bridging the interparticle space, a mechanism similar to capillary bridging that we refer to as "solid bridging." Although aggregate structure and dynamics of the bi-disperse system changes quantitatively with surface-charge of the nanoparticles, smaller particles always conferred stability on the aggregates. Investigation of other colloids, including asbestos fibers and various clays, reveals that this solid bridging effect is robust across variations in particle shape and material composition. These experiments suggest that natural mud and soil may form more stable aggregates than would naively be expected by considering the charge effects alone, because their inherent size heterogeneity is conducive to solid bridging.

  16. Determination of channel capacity of the Mokelumne River downstream from Camanche Dam, San Joaquin and Sacramento Counties, California

    USGS Publications Warehouse

    Simpson, R.G.

    1972-01-01

    This study evaluates the adequacy of a 39-mile reach of the Mokelumne River in San Joaquin and Sacramento Counties, California, to carry planned flood releases between Camanche Reservoir and the Bensons Ferry Bridge near Thornton. The flood releases from Camanche Reservoir are to be restricted, insofar as possible, so that the flows in the Mokelumne River will not exceed 5,000 cfs (cubic feet per second) as measured at the gaging station below Camanche Dam. Areas of inundation and computed floodwater profiles are based on channel conditions in late 1970 and on observed water-surface profiles during flood releases of about 5,000 cfs in January 1969 and January 1970. The inundated area shown on the maps (appendix A) and the water-surface elevations indicated on the cross sections (appendix G) are for the flood releases of those dates. The following conclusions are contingent on there being no levee failures during periods of high flow and no significant channel changes since the flood release of January 1970. 1. High tides in San Francisco Bay and, to a greater degree, flood stages on the Cosumnes River, cause backwater in the study reach. Severe backwater conditions occurring simultaneously with a flow of 5,000 cfs in the Mokelumne River can increase the flood stage 4 to 6 feet at Bensons Ferry Bridge (cross section 1). Backwater effects decrease in an upstream direction and are less than 0.5 foot at cross section 35, a river distance of 8.6 miles upstream from cross section 1, and 1.5 miles downstream from the Peltier Road bridge. 2. In the reach between cross sections 1 and 35, a 5,000 cfs release from Camanche Reservoir with maximum backwater effect (measured at cross section 1 at the mouth of the Cosumnes River) is confined within the natural or leveed banks except on the right bank flood plain between cross sections 12 and 19. 3. Upstream from cross section 35, there is overbank flooding at a flow of 5,000 cfs between cross sections 48 and 51, and 62 and 67.5. An increase in flow from 5,000 to 6,000 cfs will cause flooding between cross sections 43 and 47, 52 and 56, and 73 and 85. 4. A discharge of 5,000 cfs will pass through all bridge openings in the study reach except that of the Western Pacific Railroad Co. bridge at cross section 4. If large amounts of debris lodge on the railroad bridge when backwater from the Cosumnes River occurs, the debris could cause higher stages and flooding along the right bank between cross sections 5 and 12.

  17. Bridge-scour analysis on Cuchillo Negro Creek at the Interstate 25 crossing near Truth or Consequences, New Mexico

    USGS Publications Warehouse

    Waltemeyer, S.D.

    1995-01-01

    A sediment-transport model to simulate channel change was applied to a 1-mile reach of Cuchillo Negro Creek at the Interstate 25 crossing at Truth or Consequences, New Mexico, using the Bridge-Stream Tube model for Alluvial River Simulation (BRI-STARS). The 500-year flood discharge was estimated to be 10,700 cubic feet per second. The 100-year, 500-year, and regional maximum discharges were used to design synthetic and discretized hydrographs using a flood volume equation. The regional maximum discharge relation was developed for New Mexico based on 259 streamflow-gaging stations' maximum peak discharge. The regional maximum-peak discharge for the site was determined to be 81,700 cubic feet per second. Bed-material particle-size distribution was determined for six size classes ranging from 1 to 30 millimeters. The median diameter was 4.6 millimeters at the bed surface and 9.0 millimeters 13 feet below the bed surface. Bed-material discharge for use in the model was estimated to be 18,770 tons per day using hydraulic properties, water temperature, and Yang's gravel equation. Channel-change simulations showed a maximum channel degradation of 1.38 feet for the regional maximum-peak discharge hydrograph.

  18. Sediment-transport characteristics of Cane Creek, Lauderdale County, Tennessee

    USGS Publications Warehouse

    Carey, W.P.

    1993-01-01

    An investigation of the sediment-transport characteristics of Cane Creek in Lauderdale County, Tennessee, was conducted from 1985-88 to evaluate the potential for channel erosion induced by modifications (realignment and enlargement) and the potential ability of different flows to move bed and bank stabilizing material. Frequently occurring flows in Cane Creek are capable of moving sand-size material (0.0625 - 4.0 millimeters). During floods that equal or exceed the 2-year flood, Cane Creek is capable of moving very coarse gravel (32 - 64 millimeters). Boundary-shear values at bridges, where flow contractions occur, correspond to critical diameters in excess of 100 millimeters. Thus, the areas near bridges, where channel stability is most critical, are the areas where erosive power is greatest. Deepening and widening of Cane Creek has exposed large areas of channel boundary that are a significant source of raindrop-detached sediment during the early stages of a storm before stream flow increases signifi- cantly. This causes suspended-sediment concentration to peak while the flow hydrograph is just beginning to rise. For basins like Cane Creek, where runoff events commonly last less than a day and where variation in discharge and sediment concentrations are large, an estimate of sediment yield based on periodic observations of instantaneous values is subject to considerable uncertainty.

  19. Ion-binding properties of the ClC chloride selectivity filter

    PubMed Central

    Lobet, Séverine; Dutzler, Raimund

    2006-01-01

    The ClC channels are members of a large protein family of chloride (Cl−) channels and secondary active Cl− transporters. Despite their diverse functions, the transmembrane architecture within the family is conserved. Here we present a crystallographic study on the ion-binding properties of the ClC selectivity filter in the close homolog from Escherichia coli (EcClC). The ClC selectivity filter contains three ion-binding sites that bridge the extra- and intracellular solutions. The sites bind Cl− ions with mM affinity. Despite their close proximity within the filter, the three sites can be occupied simultaneously. The ion-binding properties are found conserved from the bacterial transporter EcClC to the human Cl− channel ClC-1, suggesting a close functional link between ion permeation in the channels and active transport in the transporters. In resemblance to K+ channels, ions permeate the ClC channel in a single file, with mutual repulsion between the ions fostering rapid conduction. PMID:16341087

  20. Relative roughness controls on incipient sediment motion in steep channels

    NASA Astrophysics Data System (ADS)

    Prancevic, J.; Lamb, M. P.; Fuller, B. M.

    2012-12-01

    For over eight decades, researchers have noted an appreciable increase in the nondimensional shear stress (Shields number) at initiation of fluvial bedload transport with increasing bed slope. The precise cause of the trend, however, is obscured by the covariance of several factors with increased slope: a greater downstream component of the gravity acting on the grains and fluid, changes in bed morphology, increased grainsize relative to the channel width that may lead to grain bridging, and increased grainsize relative to flow depth (relative roughness) that may change flow hydraulics and particle buoyancy. Here, we report on ongoing laboratory experiments spanning a wide range of bed slopes (2% to 67%) designed to isolate these variables and determine the true cause of heightened critical Shields numbers on steep slopes. First, we eliminated bed morphology as a factor by using only planar beds. To investigate the effect of grain bridging, we used two different channel widths, representing width-to-grainsize ratios of 23:1 and 9:1. Finally, to separate the effects of slope from relative roughness, we compared incipient motion conditions for acrylic particles (submerged specific gravity of 0.15) to natural siliciclastic gravel (submerged specific gravity of 1.65). Different particle densities allowed us to explore incipient motion as a function of relative roughness, independent of channel slope, because lighter particles move at shallower flow depths than heavier ones of the same size. Results show that both materials exhibit a positive trend between bed slope and critical Shields number despite the existence of planar beds for all slopes. Furthermore, changing the grainsize-to-width ratio had a negligible effect on this trend. For all slopes, the critical Shields number for bedload transport was higher for the acrylic particles than for gravel, indicating that relative roughness has a strong control on incipient sediment motion independent of channel slope. These results are consistent with a simple force balance model that considers the effect of relative roughness on flow hydraulics and particle buoyancy, and neglects grain bridging and particle wedging. Together, our results indicate that heightened critical Shields number on steep planar beds is fundamentally due to the increase in relative roughness with increasing slope at the onset of sediment motion.

  1. Level II scour analysis for Bridge 34 (CORITH0050034) on Town Highway 50, crossing the South Branch Waits River, Corinth, Vermont

    USGS Publications Warehouse

    Ivanoff, Michael A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure CORITH00500034 on Town Highway 50 crossing the South Branch Waits River, Corinth, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in central Vermont. The 35.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge while the immediate banks have dense woody vegetation. In the study area, the South Branch Waits River has an incised, meandering channel with a slope of approximately 0.005 ft/ft, an average channel top width of 63 ft and an average bank height of 6 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 23.7 mm (0.078 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 5, 1995, indicated that the reach was stable. The Town Highway 50 crossing of the South Branch Waits River is a 56-ft-long, one-lane bridge consisting of one 54-foot steel thru-truss span (Vermont Agency of Transportation, written communication, March 24, 1995). The opening length of the structure parallel to the bridge face is 51.5 ft.The bridge is supported by vertical, concrete abutments with no wingwalls. Stone fill and bank material in front of the abutments create spill-through embankments. The channel is skewed approximately 30 degrees to the opening while the opening-skew-to-roadway is 15 degrees. A scour hole 2.5 ft deeper than the mean thalweg depth was observed along the left bank through the bridge during the Level I assessment. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the left and right banks extending from upstream to downstream through the bridge. The stone fill under the bridge creates spill-through embankments. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as other potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 3.0 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was less than the 100-year discharge. Abutment scour ranged from 2.4 to 6.3 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich and HIRE equations (abutment scour) give “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  2. Twenty-First Bowditch Lecture

    ERIC Educational Resources Information Center

    Diamond, Jared M.

    1977-01-01

    Discusses the discovery, physiological function and the three roles (the bridge, the gate, and the fence) of the junctions between epithelial cells. Experimental usefulness of epithelia in studying basic questions common to all cell membranes, such as extraction of channels and carriers, or origin of ion or nonelectrolyte selectivity, is…

  3. Building Blocks for Personal Brands

    ERIC Educational Resources Information Center

    Thomas, Lisa Carlucci

    2011-01-01

    In this article, the author discusses the four essential building blocks for personal brands: (1) name; (2) message; (3) channels; and (4) bridges. However, outstanding building materials can only take a person so far. The author emphasizes that vision, determination, faith, a sense of humor, and humility are also required.

  4. 78 FR 34893 - Drawbridge Operation Regulations; Reynolds Channel, Lawrence, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... under an alternate schedule for 176 days, to facilitate electrical and structural rehabilitation at the.... Judy Leung-Yee, Project Officer, First Coast Guard District, telephone (212) 668-7165, email judy.k... temporary deviation to facilitate electrical and structural rehabilitation at the bridge. The waterway has...

  5. 41. PHOTOGRAPHY OF BLUE PRINT (MINNEAPOLIS CITY ENGINEER) END AND ...

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

    41. PHOTOGRAPHY OF BLUE PRINT (MINNEAPOLIS CITY ENGINEER) END AND CENTRE CASTING OF CAST STEEL, MASONRY CASTING OF CAST IRON CASTING, FOR MINNEAPOLIS STEEL ARCH (4 x 5 negative) - Steel Arch Bridge, Hennepin Avenue spanning west channel of Mississippi River, Minneapolis, Hennepin County, MN

  6. Digimarc MediaBridge: the birth of a consumer product from concept to commercial application

    NASA Astrophysics Data System (ADS)

    Perry, Burt; MacIntosh, Brian; Cushman, David

    2002-04-01

    This paper examines the issues encountered in the development and commercial deployment of a system based on digital watermarking technology. The paper provides an overview of the development of digital watermarking technology and the first applications to use the technology. It also looks at how we took the concept of digital watermarking as a communications channel within a digital environment and applied it to the physical print world to produce the Digimarc MediaBridge product. We describe the engineering tradeoffs that were made to balance competing requirements of watermark robustness, image quality, embedding process, detection speed and end user ease of use. Today, the Digimarc MediaBridge product links printed materials to auxiliary information about the content, via the Internet, to provide enhanced informational marketing, promotion, advertising and commerce opportunities.

  7. Level II scour analysis for Bridge 2 (RYEGTH00020002) on Town Highway 2, crossing the Wells River, Ryegate, Vermont

    USGS Publications Warehouse

    Ivanoff, Michael A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure RYEGTH00020002 on Town Highway 2 crossing the Wells River, Ryegate, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in east-central Vermont. The 75.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover consists of cut grass, trees, and brush on the flood plains while the immediate banks have dense woody vegetation. In the study area, the Wells River has an incised, sinuous channel with a slope of approximately 0.006 ft/ft, an average channel top width of 110 ft and an average bank height of 12 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 82.3 mm (0.270 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 24, 1995, indicated that the reach was laterally unstable with moderate fluvial erosion and meandering downstream of the bridge. The Town Highway 2 crossing of the Wells River is a 79-ft-long, two-lane bridge consisting of one 75-foot steel-beam span (Vermont Agency of Transportation, written communication, March 27, 1995). The opening length of the structure parallel to the bridge face is 75.1 ft. The bridge is supported by vertical, concrete abutments, the left has a spill-through embankment, with wingwalls. The channel is not skewed to the opening and the opening-skew-to-roadway is zero degrees. A scour hole 3 ft deeper than the mean thalweg depth was observed in the channel from upstream and through the bridge during the Level I assessment. The scour protection counter-measures at the site included type-4 stone fill (less than 60 inches diameter) along the base of the left abutment forming a spill-through embankment. There was also type-2 stone fill (less than 36 inches diameter) along the entire base length of the upstream right wingwall, the upstream right bank and downstream left bank. There was a stone wall along the upstream left bank extending 130 ft from the bridge. In addition there was type-1 stone fill (less than 12 inches diameter) along the downstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was zero. Abutment scour ranged from 7.1 to 11.4 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  8. Level II scour analysis for Bridge 40 (ROCKTH00140040) on Town Highway 14, crossing the Williams River, Rockingham, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ROCKTH00140040 on Town Highway 14 crossing the Williams River, Rockingham, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 99.2-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture downstream of the bridge. Upstream of the bridge, the left bank is forested and the right bank is suburban. In the study area, the Williams River has an incised, sinuous channel with a slope of approximately 0.005 ft/ft, an average channel top width of 154 ft and an average bank height of 11 ft. The channel bed material ranges from silt and clay to cobble with a median grain size (D50) of 45.4 mm (0.149 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 4, 1996, indicated that the reach was stable. The Town Highway 14 crossing of the Williams River is a 106-ft-long, one-lane covered bridge consisting of two steel-beam spans with a maximum span length of 73 ft (Vermont Agency of Transportation, written communication, April 6, 1995). The opening length of the structure parallel to the bridge face is 94.5 ft. The bridge is supported by a vertical, concrete abutment with wingwalls on the left, a vertical, laid-up stone abutment on the right and a concrete pier. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is zero degrees. A scour hole 2.1 ft deeper than the mean thalweg depth was observed towards the left side of the channel under and just downstream of the bridge during the Level I assessment. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) at the upstream end of the upstream left wingwall and type-2 stone fill (less than 36 inches diameter) along the upstream left bank and the left abutment. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was zero ft. Left abutment scour ranged from 13.9 to 19.2 ft. Right abutment scour ranged from 7.0 to 11.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Pier scour ranged from 18.7 to 24.7 ft and the worst case occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particlesize distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  9. Level II scour analysis for Bridge 37 (BARTTH00080037) on Town Highway 8, crossing Willoughby River, Barton, Vermont

    USGS Publications Warehouse

    Ayotte, Joseph D.; Boehmler, Erick M.

    1996-01-01

    of north-central Vermont in the town of Barton. The 60.4-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the banks have sparse to moderate woody vegetation coverage. In the study area, the Willoughby River is probably incised, has a sinuous channel with a slope of approximately 0.009 ft/ft, an average channel top width of 108 ft and an average channel depth of 6 ft. The predominant channel bed material is cobble (D50 is 95.1 mm or 0.312 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 20, 1994, indicated that the reach was stable. The town highway 8 crossing of the Willoughby River is a 96-ft-long, two-lane bridge consisting of one 94-foot steel-beam span (Vermont Agency of Transportation, written communication, August 4, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 15 degrees to the opening while the opening-skew-to-roadway is 10 degrees. No scour was reported in the channel or along abutments or wingwalls during the Level I assessment. Type-2 stone fill (less than 24 inches diameter) was reported at each abutment and all four wingwalls. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. Data in appendix D (Vermont Agency of Transportation, written communication, August 4, 1994) indicate that the right abutment may be founded on or near marble bedrock which may limit scour depths. Bedrock was not detected by borings in the vicinity of the left abutment. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8. Contraction scour for all modelled flows was 0 ft. Abutment scour ranged from 7.3 to 10.7 ft and the worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1993, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  10. Flood discharges and hydraulics near the mouths of Wolf Creek, Craig Branch, Manns Creek, Dunloup Creek, and Mill Creek in the New River Gorge National River, West Virginia

    USGS Publications Warehouse

    Wiley, J.B.

    1994-01-01

    The U.S. Geological Survey, in cooperation with the National Park Service, studied the frequency and magnitude of flooding near the mouths of five tributaries to the New River in the New River Gorge National River. The 100-year peak discharge at each tributary was determined from regional frequency equations. The 100-year discharge at Wolf Creek, Craig Branch, Manns Creek, Dunloup Creek, and Mill Creek was 3,400 cubic feet per second, 640 cubic feet per second, 8,200 cubic feet per second, 7,100 cubic feet per second, and 9,400 cubic feet per second, respectively. Flood elevations for each tributary were determined by application of a steady-state, one-dimensional flow model. Manning's roughness coefficients for the stream channels ranged from 0.040 to 0.100. Bridges that would be unable to contain the 100-year flood within the bridge opening included: the State Highway 82 bridge on Wolf Creek, the second Fayette County Highway 25 bridge upstream from the confluence with New River on Dunloup Creek, and an abandoned log bridge on Mill Creek.

  11. Establishment of a Continuous Wave Laser Welding Process

    DTIC Science & Technology

    1976-10-01

    gas channel . A stiff bridge clamp with threaded force points was used on half inch plate welds to iron out waviness in the test coupons. Several...34 back up channel * 10.5kW on work 11-17 ^^^^^^^ ■ u u mi u.üiijüuiiiii IK««,,.! umm j,- u.jipiHi^iMii.ijii.ijiji j! J u„„, On each of four days...welded at 40 ipm using maximum available power on the surface (12.6 KV7 for the F/7 optical system) . Contours improved but porosity formed in the

  12. Level II scour analysis for Bridge 33 (WWINTH00300033) on Town Highway 30, crossing Mill Brook, West Windsor, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Flynn, Robert H.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure WWINTH00300033 on Town Highway 30 crossing Mill Brook, West Windsor, Vermont (Figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in east-central Vermont. The 24.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream of the bridge while the immediate banks have dense woody vegetation. Downstream of the bridge is forested. In the study area, Mill Brook has an incised, sinuous channel with a slope of approximately 0.004 ft/ft, an average channel top width of 58 ft and an average bank height of 5 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 65.7 mm (0.215 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 5, 1996, indicated that the reach was stable. The Town Highway 30 crossing of the Mill Brook is a 46-ft-long, one-lane covered bridge consisting of a 40-foot wood-beam span (Vermont Agency of Transportation, written communication, March 23, 1995). The opening length of the structure parallel to the bridge face is 36.3 ft. The bridge is supported by vertical, concrete capped laid-up stone abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is zero degrees. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the upstream right bank, the upstream right wingwall, the right abutment and the downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was analyzed since it had the potential of being the worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.0 to 16.0 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  13. Use of acoustic technology to define hydraulic characteristics of an estuary near the Mississippi Gulf Coast

    USGS Publications Warehouse

    Van Wilson, K.

    2004-01-01

    An Acoustic Doppler Current Profiler (ADCP) was used on the Jourdan River at Interstate Highway 10 near Kiln, Mississippi, in 1996 to measure three-dimensional velocity vectors and water depths and in 1998, in combination with a global positioning system, to define channel bathymetry in the vicinity of the bridge. During a 25-hour period on September 19-20, 1996, 117 consecutive measurements of stage and discharge were obtained throughout a complete tidal cycle. These measurements were obtained during the time of year when headwater flows were minimal, and, therefore, the tidal-affected flow conditions were noticeable. The stage ranged from only 0.7 to 2.8 ft above sea level, but discharge ranged from 3,980 ft3/s flowing upstream to 5,580 ft 3/s flowing downstream. The average discharge during the 25-hour period was only 80 ft3/s flowing downstream. By using the ADCP, full downstream flow, bi-directional flow, and full upstream flow conditions were identified. If conventional measurement techniques had been used, the bi-directional flow conditions could not have been detected since flow direction would have been based on what was seen at the water surface. These measurements were used to define the lower range of the stage-storage-volume relation inland of the highway. On June 10, 1998, the ADCP, in combination with a global positional system, was used to define channel bathymetry for the river reach from about 3,500 ft upstream to about 2,500 ft downstream of the bridge. The bathymetry was compared to past soundings obtained in the vicinity of the bridge; as much as 18 ft of total scour was indicated to have occurred at a bridge pier. Copyright ASCE 2004.

  14. 33 CFR 118.160 - Vertical clearance gauges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... distance between “low steel” of the bridge channel span (in the closed to navigation position for... approaching vessels and extend to a reasonable height above high water so as to be meaningful to the viewer... protection structure and made of a durable material of sufficient strength to provide resistance to weather...

  15. 33 CFR 118.160 - Vertical clearance gauges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... distance between “low steel” of the bridge channel span (in the closed to navigation position for... approaching vessels and extend to a reasonable height above high water so as to be meaningful to the viewer... protection structure and made of a durable material of sufficient strength to provide resistance to weather...

  16. Monitoring the effects of knickpoint erosion on bridge pier and abutment structural damage due to scour.

    DOT National Transportation Integrated Search

    2012-04-01

    The goal of this study was to conduct a field-oriented evaluation, coupled with advanced laboratory techniques, of channel : degradation in a stream of the Deep Loess Region of western Iowa, namely Mud Creek. The Midwestern United States is : an idea...

  17. 76 FR 59121 - Notice of Availability of the Record of Decision for the Final Environmental Impact Statement...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-23

    ... lined open channels; grade control structures; bridges and drainage crossings; building pads; and water quality control facilities (sedimentation control, flood control, debris, and water quality basins). The... facilities (sedimentation control, flood debris, and water quality basins); regular and ongoing maintenance...

  18. 20. DETaIL VIEW OF UPPER EAST WALL CONTROL STATION, SHOWING ...

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

    20. DETaIL VIEW OF UPPER EAST WALL CONTROL STATION, SHOWING EMERGENCY BULKHEAD STIFFLEG DERRICK, MAIN LOCK PEDESTRIAN BRIDGE, RECESSES FOR MAIN LOCK LIFT GATE, AND TILE GAUGES, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  19. 78 FR 20451 - Drawbridge Operation Regulations; Pelican Island Causeway, Galveston, Channel, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-05

    ... severity of damage and subsequent repairs necessary for this bridge were not known until recently. In this..., to minimize litigation, eliminate ambiguity, and reduce burden. 10. Protection of Children We have analyzed this rule under Executive Order 13045, Protection of Children from Environmental Health Risks and...

  20. 19. View of dedication plaque on the north tower facing ...

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

    19. View of dedication plaque on the north tower facing south. The view is oblique because that portion of the approach trestles immediately in front of the plaque was removed in 1979. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  1. Bridging the Technology of Telecommunications into Business Communication.

    ERIC Educational Resources Information Center

    Nixon, Judy C.; West Judy F.

    A survey of companies using telecommunications equipment investigated the distribution of channel selection and the use of external mail distribution systems. A total of 50 companies responded to the survey, which identified 12 telecommunications systems and seven external mail distribution systems. Results indicated that the four most popular…

  2. 16. DETAIL, VERTICAL MEMBER L2U2 FROM BELOW AND EAST. UNUSUALLY ...

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

    16. DETAIL, VERTICAL MEMBER L2-U2 FROM BELOW AND EAST. UNUSUALLY SHAPED DESIGN REFLECTS COLUMN STRESSES ALSO NOTE LACING, WHICH COMPRISES ANGLES RATHER THAN COMMON FLAT BARS - Coraopolis Bridge, Spanning Ohio River back channel at Ferree Street & Grand Avenue, Coraopolis, Allegheny County, PA

  3. 33 CFR 117.903 - Darby Creek.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., nine inches high to indicate the vertical clearance under the closed draw at all stages of the tide... change from flashing green to flashing red anytime the bridge is not in the full open position. (10) During downward span movement, the channel traffic lights will change from flashing green to flashing red...

  4. 33 CFR 117.903 - Darby Creek.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., nine inches high to indicate the vertical clearance under the closed draw at all stages of the tide... change from flashing green to flashing red anytime the bridge is not in the full open position. (10) During downward span movement, the channel traffic lights will change from flashing green to flashing red...

  5. 33 CFR 117.903 - Darby Creek.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., nine inches high to indicate the vertical clearance under the closed draw at all stages of the tide... change from flashing green to flashing red anytime the bridge is not in the full open position. (10) During downward span movement, the channel traffic lights will change from flashing green to flashing red...

  6. 78 FR 56610 - Drawbridge Operation Regulations; Reynolds Channel, Lawrence, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-13

    ... under an alternate schedule for 92 days, to facilitate electrical and structural rehabilitation at the...: If you have questions on this rule, call or email Ms. Judy Leung-Yee, Project Officer, First Coast... structural rehabilitation at the bridge. The waterway has commercial and seasonal recreational vessels of...

  7. Modal Identification of Tsing MA Bridge by Using Improved Eigensystem Realization Algorithm

    NASA Astrophysics Data System (ADS)

    QIN, Q.; LI, H. B.; QIAN, L. Z.; LAU, C.-K.

    2001-10-01

    This paper presents the results of research work on modal identification of Tsing Ma bridge ambient testing data by using an improved eigensystem realization algorithm. The testing was carried out before the bridge was open to traffic and after the completion of surfacing. Without traffic load, ambient excitations were much less intensive, and the bridge responses to such ambient excitation were also less intensive. Consequently, the bridge responses were significantly influenced by the random movement of heavy construction vehicles on the deck. To cut off noises in the testing data and make the ambient signals more stationary, the Chebyshev digital filter was used instead of the digital filter with a Hanning window. Random decrement (RD) functions were built to convert the ambient responses to free vibrations. An improved eigensystem realization algorithm was employed to improve the accuracy and the efficiency of modal identification. It uses cross-correlation functions ofRD functions to form the Hankel matrix instead of RD functions themselves and uses eigenvalue decomposition instead of singular value decomposition. The data for response accelerations were acquired group by group because of limited number of high-quality accelerometers and channels of data loggers available. The modes were identified group by group and then assembled by using response accelerations acquired at reference points to form modes of the complete bridge. Seventy-nine modes of the Tsing Ma bridge were identified, including five complex modes formed in accordance with unevenly distributed damping in the bridge. The identified modes in time domain were then compared with those identified in frequency domain and finite element analytical results.

  8. Level II scour analysis for Bridge 43 (BENNCYDEPO0043) on Depot Street, crossing the Walloomsac River, Bennington, Vermont

    USGS Publications Warehouse

    Olson, Scott A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure BENNCYDEPO0043 on the Depot Street crossing of the Walloomsac River, Bennington, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in southwestern Vermont. The 30.1-mi2 drainage area is a predominantly rural and forested basin. The bridge site is located within an urban setting in the Town of Bennington with buildings and parking lots on overbanks. In the study area, the Walloomsac River has a straight channel with constructed channel banks through much of the reach. The channel is located on a delta and has a slope of approximately 0.02 ft/ft, an average channel top width of 48 ft and an average bank height of 6 ft. The predominant channel bed material is cobble with a median grain size (D50) of 108 mm (0.356 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 5, 1996, indicated that the reach was stable. The Depot Street crossing of the Walloomsac River is a 46-ft-long, two-lane bridge consisting of one 40-foot concrete span (Vermont Agency of Transportation, written communication, December 13, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 5 degrees to the opening and the opening-skew-to-roadway is 15 degrees. Scour countermeasures at the site include type-2 stone fill (less than 36 inches diameter) at the upstream end of the upstream right wing wall and type-1 stone fill (less than 12 inches diameter) along the base of the upstream left wing wall. Downstream banks are protected by concrete and stone walls. The upstream right bank is protected by alternating type-2 stone fill and masonry walls. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour computed for all modelled flows ranged from 0.0 to 4.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Computed right abutment scour ranged from 2.9 to 13.4 ft. with the worst-case scour occurring at the 500-year discharge. Computed left abutment scour ranged from 5.6 to 16.3 ft. with the worst-case scour also occurring at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  9. Design and experiment of a neural signal detection using a FES driving system.

    PubMed

    Zonghao, Huang; Zhigong, Wang; Xiaoying, Lu; Wenyuan, Li; Xiaoyan, Shen; Xintai, Zhao; Shushan, Xie; Haixian, Pan; Cunliang, Zhu

    2010-01-01

    The channel bridging, signal regenerating, and functional rebuilding of injured nerves is one of the most important issues in life science research. In recent years, some progresses in the research area have been made in repairing injured nerves with microelectronic neural bridge. Based on the previous work, this paper presents a neural signal detection and functional electrical stimulation (FES) driving system with using high performance operational amplifiers, which has been realized. The experimental results show that the designed system meets requirements. In animal experiments, sciatic nerve signal detection, regeneration and function rebuilding between two toads have been accomplished successfully by using the designed system.

  10. The ``cinquefoil" resistive/Hall measurement geometry

    NASA Astrophysics Data System (ADS)

    Koon, Daniel W.

    2000-03-01

    This talk begins by analyzing the charge transport weighting functions -- the sensitivity of resistive and Hall measurements to local macroscopic inhomogeneities -- of bridge-shaped transport specimens. As expected, such measurements sample only that region of the specimen between the central voltage electrodes, in the limit of narrow current channels connected by even narrower arms to the voltage electrodes. The bridge geometry has a few advantages over the van der Pauw cloverleaf geometry -- including ease in zeroing out the null-field Hall voltage -- but also some disadvantages. The talk concludes with an analysis of a hybrid geometry, the “cinquefoil” or five-leafed clover, which combines the best features of both.

  11. A new FPGA-driven P-HIFU system with harmonic cancellation technique

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Shen, Guofeng; Su, Zhiqiang; Chen, Yazhu

    2017-03-01

    This paper introduces a high intensity focused ultrasound system for ablation using switch-mode power amplifiers with harmonic cancellation technique eliminating the 3rdharmonic and all even harmonics. The efficiency of the amplifier is optimized by choosing different parameters of the harmonic cancellation technique. This technique requires double driving signals, and specific signal waveform because of the full-bridge topology. The new FPGA-driven P-HIFU system has 200 channels of phase signals that can form 100 output channels. An FPGA chip is used to generate these signals, and each channel has a phase resolution of 2 ns, less than one degree. The output waveform of the amplifier, voltage waveform across the transducer, shows fewer harmonic components.

  12. Backwater at bridges and densely wooded flood plains, west fork Amite River near Liberty, Mississippi

    USGS Publications Warehouse

    Colson, B.E.; Ming, C.O.; Arcement, George J.

    1979-01-01

    Floodflow data that will provide a base for evaluating digital models relating to open-channel flow were obtained at 22 sites on streams in Alabama, Louisiana, and Mississippi. Thirty-five floods were measured. Analysis of the data indicated methods currently in use would be inaccurate where densely vegetated flood plains are crossed by highway embankments and single-opening bridges. This atlas presents flood information at the site on West Fork Amite River near Liberty, MS. Water depths , velocities, and discharges through bridge openings on West Fork Amite River near Liberty, MS for floods of December 6, 1971 , and March 25, 1973, are shown, together with peak water-surface elevations along embankments and along cross sections. Manning 's roughness coefficient values in different parts of the flood plain are shown on maps, and flood-frequency relations are shown on a graph. (USGS).

  13. Automatic modal identification of cable-supported bridges instrumented with a long-term monitoring system

    NASA Astrophysics Data System (ADS)

    Ni, Y. Q.; Fan, K. Q.; Zheng, G.; Chan, T. H. T.; Ko, J. M.

    2003-08-01

    An automatic modal identification program is developed for continuous extraction of modal parameters of three cable-supported bridges in Hong Kong which are instrumented with a long-term monitoring system. The program employs the Complex Modal Indication Function (CMIF) algorithm to identify modal properties from continuous ambient vibration measurements in an on-line manner. By using the LabVIEW graphical programming language, the software realizes the algorithm in Virtual Instrument (VI) style. The applicability and implementation issues of the developed software are demonstrated by using one-year measurement data acquired from 67 channels of accelerometers deployed on the cable-stayed Ting Kau Bridge. With the continuously identified results, normal variability of modal vectors caused by varying environmental and operational conditions is observed. Such observation is very helpful for selection of appropriate measured modal vectors for structural health monitoring applications.

  14. Scorpion venom peptides with no disulfide bridges: a review.

    PubMed

    Almaaytah, Ammar; Albalas, Qosay

    2014-01-01

    Scorpion venoms are rich sources of biologically active peptides that are classified into disulfide-bridged peptides (DBPs) and non-disulfide-bridged peptides (NDBPs). DBPs are the main scorpion venom components responsible for the neurotoxic effects observed during scorpion envenomation as they usually target membrane bound ion channels of excitable and non-excitable cells. Several hundred DBPs have been identified and functionally characterized in the past two decades. The NDBPs represent a novel group of molecules that have gained great interest only recently due to their high diversity both in their primary structures and bioactivities. This review provides an overview of scorpion NDBPs focusing on their therapeutic applications, modes of discovery, mechanisms of NDBPs genetic diversity and structural properties. It also provides a simple classification for NDBPs that could be adopted and applied to other NDBPs identified in future studies. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Identification of unusual events in multi-channel bridge monitoring data

    NASA Astrophysics Data System (ADS)

    Omenzetter, Piotr; Brownjohn, James Mark William; Moyo, Pilate

    2004-03-01

    Continuously operating instrumented structural health monitoring (SHM) systems are becoming a practical alternative to replace visual inspection for assessment of condition and soundness of civil infrastructure such as bridges. However, converting large amounts of data from an SHM system into usable information is a great challenge to which special signal processing techniques must be applied. This study is devoted to identification of abrupt, anomalous and potentially onerous events in the time histories of static, hourly sampled strains recorded by a multi-sensor SHM system installed in a major bridge structure and operating continuously for a long time. Such events may result, among other causes, from sudden settlement of foundation, ground movement, excessive traffic load or failure of post-tensioning cables. A method of outlier detection in multivariate data has been applied to the problem of finding and localising sudden events in the strain data. For sharp discrimination of abrupt strain changes from slowly varying ones wavelet transform has been used. The proposed method has been successfully tested using known events recorded during construction of the bridge, and later effectively used for detection of anomalous post-construction events.

  16. Clear-Water Contraction Scour at Selected Bridge Sites in the Black Prairie Belt of the Coastal Plain in Alabama, 2006

    USGS Publications Warehouse

    Lee, K.G.; Hedgecock, T.S.

    2008-01-01

    The U.S. Geological Survey, in cooperation with the Alabama Department of Transportation, made observations of clear-water contraction scour at 25 bridge sites in the Black Prairie Belt of the Coastal Plain of Alabama. These bridge sites consisted of 54 hydraulic structures, of which 37 have measurable scour holes. Observed scour depths ranged from 1.4 to 10.4 feet. Theoretical clear-water contraction-scour depths were computed for each bridge and compared with observed scour. This comparison showed that theoretical scour depths, in general, exceeded the observed scour depths by about 475 percent. Variables determined to be important in developing scour in laboratory studies along with several other hydraulic variables were investigated to understand their influence within the Alabama field data. The strongest explanatory variables for clear-water contraction scour were channel-contraction ratio and velocity index. Envelope curves were developed relating both of these explanatory variables to observed scour. These envelope curves provide useful tools for assessing reasonable ranges of scour depth in the Black Prairie Belt of Alabama.

  17. Level II scour analysis for Bridge 29 (ROYATH00920029) on Town Highway 92, crossing the First Branch White River, Royalton, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Hammond, Robert E.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ROYATH00920029 on Town Highway 92 crossing the First Branch White River, Royalton, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in central Vermont. The 101-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge. In the study area, the First Branch White River has an incised, sinuous channel with a slope of approximately 0.001 ft/ft, an average channel top width of 81 ft and an average bank height of 9 ft. The channel bed material ranges from sand to bedrock with a median grain size (D50) of 1.18 mm (0.00347 ft). The geomorphic assessment at the time of the Level I site visit on July 23, 1996 and Level II site visit on June 2, 1995, indicated that the reach was stable. The Town Highway 92 crossing of the First Branch White River is a 59-ft-long, one-lane bridge consisting of a 57-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 23, 1995). The opening length of the structure parallel to the bridge face is 52.2 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 20 degrees to the opening while the opening-skew-to-roadway is zero degrees. A scour hole 4.0 ft deeper than the mean thalweg depth was observed in the upstream channel during the Level I assessment. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the upstream left and right wingwalls, the left abutment and downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 4.1 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was less than the 100-year discharge. Left abutment scour ranged from 12.9 to 15.4 ft, where the worst-case abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 14.5 to 15.0 ft, where the worst-case abutment scour occurred at the 100-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  18. Level II scour analysis for Bridge 68 (NFIETH00960068) on Town Highway 96, crossing the Dog River, Northfield, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure NFIETH00960068 on Town Highway 96 crossing the Dog River, Northfield, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 30.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover on the left bank upstream and downstream is pasture while the immediate banks have dense woody vegetation. The right bank upstream is forested and the downstream right bank is pasture. Vermont state route 12A runs parallel to the river on the right bank. In the study area, the Dog River has an incised, straight channel with a slope of approximately 0.004 ft/ft, an average channel top width of 70 ft and an average bank height of 7 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 47.9 mm (0.157 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 25, 1996, indicated that the reach was stable. The Town Highway 96 crossing of the Dog River is a 45-ft-long, one-lane bridge consisting of one 43-foot steel-beam span with a timber deck (Vermont Agency of Transportation, written communication, October 13, 1995). The opening length of the structure parallel to the bridge face is 41.5 ft.The bridge is supported by vertical, concrete abutments with wingwalls. The channel is not skewed to the opening and the opening-skew-to-roadway is zero degrees. Channel scour 0.5 ft deeper than the mean thalweg depth, was observed under the bridge during the Level I assessment. The scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) along the left bank upstream and type-2 stone fill (less than 36 inches diameter) along the upstream and downstream right banks that extends partially in front of the right wingwalls. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.8 to 1.2 ft. The worst-case contraction scour occurred at the 100-year and 500-year discharges. Abutment scour ranged from 8.5 to 12.2 ft. The worst-case abutment scour occurred at the incipient roadway-overtopping discharge for the right abutment. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  19. Level II scour analysis for Bridge 17 (RIPTTH00180017) on Town Highway 18, crossing the South Branch Middlebury River, Ripton, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Medalie, Laura

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure RIPTTH00180017 on Town Highway 18 crossing the South Branch Middlebury River, Ripton, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in west-central Vermont. The 15.5-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest except on the upstream left bank where it is shrubs and brush. In the study area, the South Branch Middlebury River has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 86 ft and an average bank height of 10 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 111 mm (0.364 ft). In addition, there is a bedrock outcrop across the channel downstream of the bridge. The geomorphic assessment at the time of the Level I and Level II site visit on June 10, 1996, indicated that the reach was stable. The Town Highway 18 crossing of the South Branch Middlebury River is a 61-ft-long, one-lane bridge consisting of one 58-foot steel-beam span (Vermont Agency of Transportation, written communication, November 30, 1995). The opening length of the structure parallel to the bridge face is 56.8 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 40 degrees to the opening while the computed opening-skew-to-roadway is 30. A scour hole 1.25 ft deeper than the mean thalweg depth was observed along the right abutment and the downstream right wingwall during the Level I assessment. The scour protection measures at the site include type-2 stone fill (less than 36 inches diameter) along the left abutment and it’s wingwalls and at the upstream end of the right abutment. Also, type-3 stone fill (less than 48 inches diameter) is along the upstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.1 to 1.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 5.6 to 9.0 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  20. Level II scour analysis for Bridge 4 (DANVTH00010004) on Town Highway 1, crossing Joes Brook, Danville, Vermont

    USGS Publications Warehouse

    Flynn, Robert H.; Boehmler, Erick M.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure DANVTH00010004 on Town Highway 1 crossing Joes Brook, Danville, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in northeastern Vermont. The 42.5-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture along the upstream and downstream left banks with trees and brush along the immediate banks. The upstream and downstream right banks are forested. In the study area, Joes Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 68 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to bedrock with a median grain size (D50) of 80.1 mm (0.263 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 22, 1995, indicated that the reach was stable. The Town Highway 1 crossing of Joes Brook is a 49-ft-long, two-lane bridge consisting of one 45-foot steel-beam span (Vermont Agency of Transportation, written communication, March 17, 1995). The opening length of the structure parallel to the bridge face is 45 ft.The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 15 degrees to the opening and the computed opening-skew-to-roadway is 15 degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. The scour hole also extends upstream and downstream of the bridge, along the right side of the channel. The scour protection measures at the site include type-2 stone fill (less than 36 inches diameter) at the upstream end of the upstream left wingwall and along the entire base length of the downstream right wingwall. Type-3 stone fill (less than 48 inches diameter) is along the entire base length of the upstream right wingwall and type-5 protection (stone block wall) is along the upstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was computed to be zero ft. Abutment scour ranged from 11.7 to 13.0 ft along the right abutment and from 6.6 to 9.4 ft along the left abutment. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich and Hire equations (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  1. Level II scour analysis for Bridge 31 (JERITH00350031) on Town Highway 35, crossing Mill Brook, Jericho, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure JERITH00350031 on Town Highway 35 crossing Mill Brook, Jericho, Vermont (figures 1– 8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gathered from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province and the Champlain section of the St. Lawrence physiographic province in northwestern Vermont. The 15.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream of the bridge. The downstream left overbank is pasture. The downstream right overbank is brushland. In the study area, the Mill Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 117 ft and an average bank height of 11 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 81.1 mm (0.266 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 3, 1996, indicated that the reach was laterally unstable. The Town Highway 35 crossing of the Mill Brook is a 53-ft-long, one-lane bridge consisting of a 50-foot steel-beam span with a wooden deck (Vermont Agency of Transportation, written communication, November 30, 1995). The opening length of the structure parallel to the bridge face is 48 ft. The bridge is supported by a vertical, concrete abutment with wingwalls on the left. On the right, the abutment and wingwalls are laid-up stone with a concrete cap. The channel is not skewed to the opening. The roadway is skewed 10 degrees to the opening. A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the left abutment during the Level I assessment. Scour countermeasures at the site were type-2 stone fill (less than 36 inches diameter) at the upstream and downstream left wingwalls, the upstream and downsteam left channel banks, and the downstream left road embankment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). In addition, the incipient roadway-overtopping discharge is analyzed since it has the potential of being the worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.4 to 1.3 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 9.9 to 12.4 ft. Right abutment scour ranged from 13.8 to 17.8 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  2. Level II scour analysis for Bridge 13 (PFRDTH00030013) on Town Highway 3, crossing Furnace Brook, Pittsford, Vermont

    USGS Publications Warehouse

    Flynn, Robert H.; Medalie, Laura

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure PFRDTH00030013 on Town Highway 3 crossing Furnace Brook, Pittsford, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Taconic section of the New England physiographic province in western Vermont. The 17.1-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is grass along the downstream right bank while the remaining banks are primarily forested. In the study area, Furnace Brook has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 49 ft and an average channel depth of 4 ft. The predominant channel bed material ranges from gravel to bedrock with a median grain size (D50) of 70.2 mm (0.230 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 20, 1995, indicated that the reach was stable. The Town Highway 3 crossing of Furnace Brook is a 75-ft-long, two-lane bridge consisting of one 72-ft-long steel stringer span (Vermont Agency of Transportation, written communication, March 14, 1995). The bridge is supported by vertical, concrete abutments with spill-through slopes. The channel is skewed approximately 20 degrees to the opening while the opening-skew-to-roadway is 35 degrees. The opening-skew-to-roadway was determined from surveyed data collected at the bridge although, information provided from the VTAOT files, indicates that the opening-skew-to-roadway is 30 degrees (Appendix D). The scour protection measures at the site included type-2 stone fill (less than 36 inches diameter) on the spill-through slope along each abutment. Type-2 stone fill scour protection was also found along the upstream left wingwall and downstream right wingwall. Type-1 (less than 12 inches diameter) stone fill scour protection was found along the upstream right wingwall and downstream left wingwall. No bank protection was observed downstream or upstream. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.2 to 2.0 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 7.8 to 13.1 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution although, bedrock outcropping is apparent both upstream and downstream of this bridge. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  3. Design of high-energy high-current linac with focusing by superconducting solenoids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Batskikh, Guennady I.; Belugin, Vladimir M.; Bondarev, Boris I.

    1995-09-15

    The advancement of MRTI design for 1.5 GeV and 250 mA ion CW linac is presented in the report. In new linac version all the way from input to output the ions are focused by magnetic fields of superconducting solenoids. The ion limit current is far beyond the needed value. The linac focusing channel offers major advantages over the more conventional ones. The acceptance is 1.7 times as large for such focusing channel as for quadrupole one. Concurrently, a random perturbation sensitivity for such channel is one order of magnitude smaller than in quadrupole channel. These focusing channel features allowmore » to decrease beam matched radius and increase a linac radiation purity without aperture growth. ''Regotron'' is used as high power generator in linac main part. But D and W cavities need not be divided into sections connected by RF-bridges which denuded them of high coupling factor.« less

  4. Activation of acid-sensing ion channels by localized proton transient reveals their role in proton signaling.

    PubMed

    Zeng, Wei-Zheng; Liu, Di-Shi; Liu, Lu; She, Liang; Wu, Long-Jun; Xu, Tian-Le

    2015-09-15

    Extracellular transients of pH alterations likely mediate signal transduction in the nervous system. Neuronal acid-sensing ion channels (ASICs) act as sensors for extracellular protons, but the mechanism underlying ASIC activation remains largely unknown. Here, we show that, following activation of a light-activated proton pump, Archaerhodopsin-3 (Arch), proton transients induced ASIC currents in both neurons and HEK293T cells co-expressing ASIC1a channels. Using chimera proteins that bridge Arch and ASIC1a by a glycine/serine linker, we found that successful coupling occurred within 15 nm distance. Furthermore, two-cell sniffer patch recording revealed that regulated release of protons through either Arch or voltage-gated proton channel Hv1 activated neighbouring cells expressing ASIC1a channels. Finally, computational modelling predicted the peak proton concentration at the intercellular interface to be at pH 6.7, which is acidic enough to activate ASICs in vivo. Our results highlight the pathophysiological role of proton signalling in the nervous system.

  5. Quantum photonic network and physical layer security

    NASA Astrophysics Data System (ADS)

    Sasaki, Masahide; Endo, Hiroyuki; Fujiwara, Mikio; Kitamura, Mitsuo; Ito, Toshiyuki; Shimizu, Ryosuke; Toyoshima, Morio

    2017-06-01

    Quantum communication and quantum cryptography are expected to enhance the transmission rate and the security (confidentiality of data transmission), respectively. We study a new scheme which can potentially bridge an intermediate region covered by these two schemes, which is referred to as quantum photonic network. The basic framework is information theoretically secure communications in a free space optical (FSO) wiretap channel, in which an eavesdropper has physically limited access to the main channel between the legitimate sender and receiver. We first review a theoretical framework to quantify the optimal balance of the transmission efficiency and the security level under power constraint and at finite code length. We then present experimental results on channel characterization based on 10 MHz on-off keying transmission in a 7.8 km terrestrial FSO wiretap channel. This article is part of the themed issue 'Quantum technology for the 21st century'.

  6. Quantum photonic network and physical layer security.

    PubMed

    Sasaki, Masahide; Endo, Hiroyuki; Fujiwara, Mikio; Kitamura, Mitsuo; Ito, Toshiyuki; Shimizu, Ryosuke; Toyoshima, Morio

    2017-08-06

    Quantum communication and quantum cryptography are expected to enhance the transmission rate and the security (confidentiality of data transmission), respectively. We study a new scheme which can potentially bridge an intermediate region covered by these two schemes, which is referred to as quantum photonic network. The basic framework is information theoretically secure communications in a free space optical (FSO) wiretap channel, in which an eavesdropper has physically limited access to the main channel between the legitimate sender and receiver. We first review a theoretical framework to quantify the optimal balance of the transmission efficiency and the security level under power constraint and at finite code length. We then present experimental results on channel characterization based on 10 MHz on-off keying transmission in a 7.8 km terrestrial FSO wiretap channel.This article is part of the themed issue 'Quantum technology for the 21st century'. © 2017 The Author(s).

  7. 5. SITE OVERVIEW. DETAIL VIEW OF INTERCHANGE OF ARROYO SECO ...

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

    5. SITE OVERVIEW. DETAIL VIEW OF INTERCHANGE OF ARROYO SECO PARKWAY AT RIGHT, INTERSTATE 1-5 AT CENTER, AND FIGUEROA STREET AT LEFT. NOTE ARROYO SECO CHANNEL PARALLEL TO PARKWAY. NOTE AVENUE 26 BRIDGE AT CENTER. LOOKING 30° NNE. - Arroyo Seco Parkway, Los Angeles to Pasadena, Los Angeles, Los Angeles County, CA

  8. 33 CFR 118.160 - Vertical clearance gauges.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of the foot marks, read from top to bottom. Each gauge must be installed on the end of the right... directly on the bridge channel pier or pier protection structure if the surface is suitable and has... be marked by black numerals and foot marks on a white background. Paint, if used, must be of good...

  9. 33 CFR 118.160 - Vertical clearance gauges.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of the foot marks, read from top to bottom. Each gauge must be installed on the end of the right... directly on the bridge channel pier or pier protection structure if the surface is suitable and has... be marked by black numerals and foot marks on a white background. Paint, if used, must be of good...

  10. 33 CFR 162.235 - Puget Sound Area, Wash.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... within the canal grounds unless they are well over on the tide flats to the west of the dredged channel... Company bridges crossing this narrow section, shall be governed by red and green traffic signal lights... that the waterway is clear. Two red lights, one vertically above the other, displayed ahead of a vessel...

  11. 33 CFR 162.235 - Puget Sound Area, Wash.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... within the canal grounds unless they are well over on the tide flats to the west of the dredged channel... Company bridges crossing this narrow section, shall be governed by red and green traffic signal lights... that the waterway is clear. Two red lights, one vertically above the other, displayed ahead of a vessel...

  12. 33 CFR 162.235 - Puget Sound Area, Wash.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... within the canal grounds unless they are well over on the tide flats to the west of the dredged channel... Company bridges crossing this narrow section, shall be governed by red and green traffic signal lights... that the waterway is clear. Two red lights, one vertically above the other, displayed ahead of a vessel...

  13. 50. Neg. No. F176B, Jun 5, 1936, EXTERIORFORD ASSEMBLY PLANT ...

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

    50. Neg. No. F-176B, Jun 5, 1936, EXTERIOR-FORD ASSEMBLY PLANT AT LONG BEACH, OVERALL VIEW OF PLANT FROM THE HENRY FORD BRIDGE, CERRITOS CHANNEL IN THE FOREGROUND - Ford Motor Company Long Beach Assembly Plant, Assembly Building, 700 Henry Ford Avenue, Long Beach, Los Angeles County, CA

  14. Experiments and Analyses of the Formation of Erosional Scour Marks with Implications to the Origin of the Martian Outflow Channels

    NASA Technical Reports Server (NTRS)

    Komar, P. D.

    1985-01-01

    The objectives of the present study of erosional scour marks on Mars involve flume experiments to examine the details of scour patterns around a variety of obstacle shapes, and to review the engineering literature on the scour around bridge piers to determine whether those results might provide a quantitative evaluation of the flows which formed the scour marks in the outflow channels. The flume experiments completed to date examined the scour which develops around a circular island and around a streamlined island (having a lemniscate shape with length/width = 3.0). The islands themselves are non-erodable solids, but are surrounded by a fine-grained sediment bed. The scour patterns which occur around the circular island agree with those produced by prototype bridge piers and by scale-model piers employed in the engineering studies. The scour patterns around the model streamlined islands correspond extremely well with those seen adjacent to the streamlined islands on Mars, providing still more confirmation for a water-flow origin.

  15. Remote-Sensing Survey of the Atchafalaya Basin Main Channel, Atchafalaya Channel Training Project, Sts. Martin and Mary Parishes, Louisiana

    DTIC Science & Technology

    1991-11-01

    Just above Cornay’s Bridge they sunk the steamer Flycatcher and a schooner loaded with bricks, plus live oak trees were cut down and thrown into the...contour level) (Feet) Single Objects Engine camshaft 20 fi x 2 m 45 45 x 50 feet 15 Cas’ Iron soil pipe 10 ft long. 100 lbs 1407 45 x 65 feet 4 Iron...hitting any of the numerous fallen trees , snags, submerged logs, shallow sand bars, etc., 52 Chapter 3. Remote-Sensing Survey which occur along much of the

  16. A simplified GIS-based model for large wood recruitment and connectivity in mountain basins

    NASA Astrophysics Data System (ADS)

    Lucía, Ana; Antonello, Andrea; Campana, Daniela; Cavalli, Marco; Crema, Stefano; Franceschi, Silvia; Marchese, Enrico; Niedrist, Martin; Schneiderbauer, Stefan; Comiti, Francesco

    2014-05-01

    The mobilization of large wood (LW) elements in mountain rivers channels during floods may increase their hazard potential, especially by clogging narrow sections such as bridges. However, the prediction of LW transport magnitude during flood events is a challenging topic. Although some models on LW transport have been recently developed, the objective of this work was to generate a simplified GIS-based model to identify along the channel network the most likely LW-related critical sections during high-magnitude flood events in forested mountain basins. Potential LW contribution generated by landsliding occurring on hillslopes is assessed using SHALSTAB stability model coupled to a GIS-based connectivity index, developed as a modification of the index proposed by Cavalli et al (2013). Connected slope-derived LW volumes are then summed at each raster cell to LW volumes generated by bank erosion along the erodibile part of river corridors, where bank erosion processes are estimated based on user-defined channel widening ratios stemming from observations following recent extreme events in mountain basins. LW volume in the channel is then routed through the stream network applying simple Boolean rules meant to capture the most important limiting transport condition in these high-energy systems at flood stage, i.e. flow width relative to log length. In addition, the role of bridges and retention check-dams in blocking floating logs is accounted for in the model, in particular bridge length and height are used to characterize their clogging susceptibility for different levels of expected LW volumes and size. The model has been tested in the Rienz and Ahr basins (about 630 km2 each), located in the Eastern Italian Alps. Sixty percent of the basin area is forested, and elevations range from 811 m a.s.l. to 3488 m a.s.l.. We used a 2.5 m resolution DTM and DSM, and their difference was used to calculate the canopy height. Data from 35 plots of the National Forest Inventory were used to estimate forest stand volume by a semi-empirical model. Ddatabase on shallow landslides along with precipitation depth was utilized to calibrate the parameters for the SHALSTAB model. Orthophotos (0.5 m pixel resolution) and existing technical maps were used to delimitate the channel banks, which were used to calculate automatically channel width for each grid cell. The model output provided information about the expected volume and mean size of LW recruited and transported during a 300 yr flood event in the test basins, as well as the location of the most probable clogged sections (mostly related to infrastructures) along the channel network. The model thus shows the capability to assist river managers in identifying the most critical sections of river networks and to assess the effectiveness and location of different mitigation options such as wood retention structures or forest management practices.

  17. Level II scour analysis for Bridge 23 (WOLCTH00130023) on Town Highway 13, crossing the Wild Branch of the Lamoille River, Wolcott, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Degnan, James R.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure WOLCTH00130023 on Town Highway 13 crossing the Wild Branch Lamoille River, Wolcott, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, collected from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in northcentral Vermont. The 27.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture on the upstream right overbank. The upstream left overbank is brushland. Downstream of the bridge, the surface cover is forested on the right overbank. The downstream left overbank is pasture while the immediate bank has dense woody vegetation. In the study area, the Wild Branch Lamoille River has an incised, straight channel with a slope of approximately 0.009 ft/ft, an average channel top width of 65 ft and an average bank height of 7 ft. The channel bed material ranges from sand to boulders with a median grain size (D50) of 85.3 mm (0.280 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 17, 1996 indicated that the reach was laterally unstable. The Town Highway 13 crossing of the Wild Branch Lamoille River is a 41-ft-long, one-lane bridge consisting of a 39-foot steel girder span (Vermont Agency of Transportation, written communication, October 13, 1995). The opening length of the structure parallel to the bridge face is 38 ft. The bridge is supported by vertical, concrete abutments. The right abutment has concrete wingwalls. The channel is skewed approximately 45 degrees to the opening while the opening-skew-to-roadway is zero degrees. A scour hole 3.5 ft deeper than the mean thalweg depth was observed in the channel during the Level I assessment. Scour countermeasures at the site includes type-2 stone fill (less than 3 feet diameter) along the banks, the right wingwalls, the right abutment and the road embankments. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.0 to 2.1 ft. The worst-case contraction scour occurred at the 100-year discharge. Left abutment scour ranged from 9.1 to 13.2 ft. Right abutment scour ranged from 15.7 to 22.3 ft. The worst-case abutment scour occurred at the 500- year discharge for both abutments. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. During the August 1995 flood, the Wild Branch Lamoille River overtopped the bridge deck at structure WOLCTH00130023. Debris also was caught in the upstream I-beam of the structure. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  18. Level II scour analysis for Bridge 5 (WOLCTH00150005) on Town Highway 15, crossing the Wild Branch Lamoille River, Wolcott, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure WOLCTH00150005 on Town Highway 15 crossing the Wild Branch Lamoille River, Wolcott, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.During the August 1995 and July 1997 flood events, the left roadway was overtopped. Although there was loss of stone fill along the right abutment, the structure withstood both events.The site is in the Green Mountain section of the New England physiographic province in north- central Vermont. The 38.3-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge, while the immediate banks have dense woody vegetation.In the study area, the Wild Branch Lamoille River has an incised, sinuous channel with a slope of approximately 0.006 ft/ft, an average channel top width of 98 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to bedrock with a median grain size (D50) of 89.1 mm (0.292 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 17, 1996, indicated that the reach was stable.The Town Highway 15 crossing of the Wild Branch Lamoille River is a 46-ft-long, two-lane bridge consisting of a 43-foot prestressed concrete box-beam span (Vermont Agency of Transportation, written communication, October 13, 1995). The opening length of the structure parallel to the bridge face is 42 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening- skew-to-roadway is zero degrees.A scour hole 2.0 ft deeper than the mean thalweg depth was observed near the bridge along the left side of the channel during the Level I assessment. Scour countermeasures at the site consists of type-1 stone fill (less than 12 inches diameter) along the upstream left bank and along the left and right downstream banks, type-2 stone fill (less than 36 inches diameter) along the downstream left and right wingwalls, type-3 stone fill (less than 48 inches diameter) along the upstream left wingwall and the right abutment, and type-4 stone fill (less than 60 inches diameter) along the upstream right wingwall and the left abutment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled flows was zero ft. Left abutment scour ranged from 7.9 to 23.3 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 21.5 to 22.8 ft. The worst-case right abutment scour occurred at the incipient roadway-overtopping discharge. Additional in formation on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross- section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  19. Hydraulic analyses of water-surface profiles in the vicinity of the Coamo Dam and Highway 52 Bridge, southern Puerto Rico; flood analyses as related to the flood of October 7, 1985

    USGS Publications Warehouse

    Johnson, K.G.; Quinones-Marquez, Ferdinand; Gonzalez, Ralph

    1987-01-01

    The magnitude, frequency and extent of the flood of October 7, 1985 at the Rio Coamo in the vicinity of the Coamo Dam and Highway 52 bridge in southern Puerto Rico, were investigated. The observed flood profiles were used to calibrate a step-backwater model. The calibrated model was then used to investigate several alternative flow conditions in the vicinity of the bridge. The peak discharge of the flood at the Highway 52 bridge was 72,000 cu ft/sec. This peak discharge was determined from the peak computed at a reach in the vicinity of the Banos de Coamo, about 1.2 mi upstream from the bridge. The computed discharge at the Banos de Coamo of 66,000 cu ft/sec was adjusted to the dam and bridge location by multiplying it by the ratio of the drainage areas raised to the 0.83 power. The flood had a recurrence interval of about 100 yr, exceeding all previously known floods at the site. The flood overtopped the spillway and levee of the Coamo Dam just upstream of Highway 52. The flow over the spillway was 54,000 cu ft/sec. Flow over the levee was about 18,000 cu ft/sec. About 10,000 cu ft/sec of the flow over the levee returned to the main channel at the base of the embankment at the northeast approach to the bridge. The remaining 8,000 cu ft/sec flowed south through the underpass on Highway 153. The embankment and shoulder on the northern span of the bridge were eroded with the eventual collapse of the approach slab. (Author 's abstract)

  20. Unexpected Connections between Humidity and Ion Transport Discovered Using a Model to Bridge Guard Cell-to-Leaf Scales.

    PubMed

    Wang, Yizhou; Hills, Adrian; Vialet-Chabrand, Silvere; Papanatsiou, Maria; Griffiths, Howard; Rogers, Simon; Lawson, Tracy; Lew, Virgilio L; Blatt, Michael R

    2017-11-01

    Stomatal movements depend on the transport and metabolism of osmotic solutes that drive reversible changes in guard cell volume and turgor. These processes are defined by a deep knowledge of the identities of the key transporters and of their biophysical and regulatory properties, and have been modeled successfully with quantitative kinetic detail at the cellular level. Transpiration of the leaf and canopy, by contrast, is described by quasilinear, empirical relations for the inputs of atmospheric humidity, CO 2 , and light, but without connection to guard cell mechanics. Until now, no framework has been available to bridge this gap and provide an understanding of their connections. Here, we introduce OnGuard2, a quantitative systems platform that utilizes the molecular mechanics of ion transport, metabolism, and signaling of the guard cell to define the water relations and transpiration of the leaf. We show that OnGuard2 faithfully reproduces the kinetics of stomatal conductance in Arabidopsis thaliana and its dependence on vapor pressure difference (VPD) and on water feed to the leaf. OnGuard2 also predicted with VPD unexpected alterations in K + channel activities and changes in stomatal conductance of the slac1 Cl - channel and ost2 H + -ATPase mutants, which we verified experimentally. OnGuard2 thus bridges the micro-macro divide, offering a powerful tool with which to explore the links between guard cell homeostasis, stomatal dynamics, and foliar transpiration. © 2017 American Society of Plant Biologists. All rights reserved.

  1. ENHANCEMENT OF A SUNSPOT LIGHT WALL WITH EXTERNAL DISTURBANCES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Shuhong; Zhang, Jun; Erdélyi, Robert, E-mail: shuhongyang@nao.cas.cn

    Based on the Interface Region Imaging Spectrograph observations, we study the response of a solar sunspot light wall to external disturbances. A flare occurrence near the light wall caused material to erupt from the lower solar atmosphere into the corona. Some material falls back to the solar surface and hits the light bridge (i.e., the base of the light wall), then sudden brightenings appear at the wall base followed by the rise of wall top, leading to an increase of the wall height. Once the brightness of the wall base fades, the height of the light wall begins to decrease.more » Five hours later, another nearby flare takes place, and a bright channel is formed that extends from the flare toward the light bridge. Although no obvious material flow along the bright channel is found, some ejected material is conjectured to reach the light bridge. Subsequently, the wall base brightens and the wall height begins to increase again. Once more, when the brightness of the wall base decays, the wall top fluctuates to lower heights. We suggest, based on the observed cases, that the interaction of falling material and ejected flare material with the light wall results in the brightenings of wall base and causes the height of the light wall to increase. Our results reveal that the light wall can be not only powered by the linkage of p -mode from below the photosphere, but may also be enhanced by external disturbances, such as falling material.« less

  2. Level II scour analysis for Bridge 33 (HUNTTH00220033) on Town Highway 22, crossing Brush Brook, Huntington, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Degnan, James R.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure HUNTTH00220033 on Town Highway 22 crossing Brush Brook, Huntington, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 8.65-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest except on the downstream right overbank which is pasture. In the study area, Brush Brook has an incised, straight channel with a slope of approximately 0.04 ft/ft, an average channel top width of 42 ft and an average bank height of 3 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 76.7 mm (0.252 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 26, 1996, indicated that the reach was stable. The Town Highway 22 crossing of Brush Brook is a 40-ft-long, two-lane bridge consisting of one 23.5-foot concrete slab span (Vermont Agency of Transportation, written communication, November 30, 1995). The opening length of the structure parallel to the bridge face is 36.9 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 35 degrees to the opening while the opening-skew-to-roadway is 30 degrees. The scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the left and right banks upstream that extended through the bridge and along the downstream banks. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is analyzed since it has the potential of being the worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 1.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.5 to 14.9 ft. The worst-case abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  3. Level II scour analysis for Bridge 22 (JAY-TH00400022) on Town Highway 40, crossing Jay Branch, Jay, Vermont

    USGS Publications Warehouse

    Ivanoff, Michael A.; Song, Donald L.

    1997-01-01

    8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in northern Vermont. The 2.15-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is primarily pasture on the upstream and downstream left overbank while the immediate banks have dense woody vegetation. The downstream right overbank of the bridge is forested. In the study area, Jay Branch Tributary has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 26 ft and an average bank height of 3 ft. The channel bed material ranges from gravel to cobble with a median grain size (D50) of 40.5 mm (0.133 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 7, 1995, indicated that the reach was stable. The Town Highway 40 crossing of Jay Branch Tributary is a 27-ft-long, two-lane bridge consisting of one 25-foot steel-beam span (Vermont Agency of Transportation, written communication, March 6, 1995). The opening length of the structure parallel to the bridge face is 23.5 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel skew and the opening-skew-to-roadway are zero degrees. The scour counter-measures at the site included type-2 stone fill (less than 36 inches diameter) at the upstream end of the left and right abutments, at the upstream right wingwall, and at the downstream left wingwall. There was also type-3 stone fill (less than 48 inches diameter) at the upstream left and downstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.7 to 1.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 4.6 to 4.9 ft. The worst-case left abutment scour occurred at the 100-year discharge. Right abutment scour ranged from 4.0 to 5.0 ft. The worst-case right abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  4. Man-induced channel adjustment in Tennessee streams

    USGS Publications Warehouse

    Robbins, C.H.; Simon, Andrew

    1983-01-01

    Channel modifications in Tennessee, particularly in the western part, have led to large-scale instabilities in the channelized rivers and may have contributed to several bridge failures. These modifications, together with land-use practices, led to downcutting, headward erosion, downstream aggradation, accelerated scour, and bank instabilities. Changes in gradient by channel straightening caused more severe channel response than did dredging or clearing. Large-scale changes continue to occur in all the channelized rivers: the Obion River, its forks, and the South Fork Forked Deer River. However, the non-channelized Hatchie River in west Tennessee not only withstood the natural stresses imposed by the wet years of 1973 to 1975 but continues to exhibit characteristics of stability. Water-surface slope, the primary dependent variable, proved to be a sensitive and descriptive parameter useful in determining channel adjustment. Adjustments to man-induced increases in channel-slope are described by inverse exponential functions of the basic form S=ae(-b(t)); where ' S ' is some function describing channel-slope, ' t ' is the number of years since completion of channel work, and ' a ' and ' b ' are coefficients. Response times for the attainment of ' equilibrium ' channel slopes are a function of the magnitude and extent of the imposed modifications. The adjusted profile gradients attained by the streams following channelization are similar to the predisturbed profile gradients, where no alteration to channel length was made. Where the channels were straightened by constructing cut-offs, thus shortening channel length, then slope adjustments (reduction) proceed past the predisturbed profile gradients, to new profiles with lower gradients. (USGS)

  5. Dissociative electron attachment to DNA-diamine thin films: Impact of the DNA close environment on the OH− and O− decay channels

    PubMed Central

    Boulanouar, Omar; Fromm, Michel; Mavon, Christophe; Cloutier, Pierre; Sanche, Léon

    2013-01-01

    We measure the desorption of anions stimulated by the impact of 0–20 eV electrons on highly uniform thin films of plasmid DNA-diaminopropane. The results are accurately correlated with film thickness and composition by AFM and XPS measurements, respectively. Resonant structures in the H−, O−, and OH− yield functions are attributed to the decay of transient anions into the dissociative electron attachment (DEA) channel. The diamine induces ammonium-phosphate bridges along the DNA backbone, which suppresses the DEA O− channel and in counter-part increases considerably the desorption of OH−. The close environment of the phosphate groups may therefore play an important role in modulating the rate and type of DNA damages induced by low energy electrons. PMID:23927286

  6. Stenting for Acute Aortic Dissection with Malperfusion as “Bridge Therapy”

    PubMed Central

    Fujita, Wakako; Taniguchi, Satoshi; Daitoku, Kazuyuki; Fukuda, Ikuo

    2010-01-01

    The most common treatment of acute type A aortic dissection is immediate surgical repair. However, early surgery for acute dissections with peripheral vascular compromise carries a high mortality rate. Herein, we report a case in which we placed percutaneous endovascular stents in a type A dissection patient before proceeding with proximal aortic repair. Bare-metal stents were placed into the obliterated true channel of the abdominal aorta and the left external iliac artery. Endovascular stenting immediately relieved the lower-left-extremity ischemic symptoms, and the patient underwent hemi-arch replacement 7 days after the procedure. Stent placement for patients who have acute aortic dissection with malperfusion can be used as “bridge therapy.” PMID:21224949

  7. The Semantic Environment: Heuristics for a Cross-Context Human-Information Interaction Model

    NASA Astrophysics Data System (ADS)

    Resmini, Andrea; Rosati, Luca

    This chapter introduces a multidisciplinary holistic approach for the general design of successful bridge experiences as a cross-context human-information interaction model. Nowadays it is common to interact through a number of different domains in order to communicate successfully, complete a task, or elicit a desired response: Users visit a reseller’s web site to find a specific item, book it, then drive to the closest store to complete their purchase. As such, one of the crucial challenges user experience design will face in the near future is how to structure and provide bridge experiences seamlessly spanning multiple communication channels or media formats for a specific purpose.

  8. Exploring the dynamic behaviors and transport properties of gas molecules in a transmembrane cyclic peptide nanotube.

    PubMed

    Li, Rui; Fan, Jianfen; Li, Hui; Yan, Xiliang; Yu, Yi

    2013-12-05

    The dynamic behaviors and transport properties of O2, CO2, and NH3 molecules through a transmembrane cyclic peptide nanotube (CPNT) of 8×cyclo-(WL)4/POPE have been investigated by steered molecular dynamics (SMD) simulations and adaptive biasing force (ABF) samplings. Different external forces are needed for three gas molecules to enter the channel. The periodic change of the pulling force curve for a gas traveling through the channel mainly arises from the regular and periodic arrangement of the composed CP subunits of the CPNT. Radial distribution functions (RDFs) between gas and water disclose the density decrease of channel water, which strongly aggravates the discontinuity of H-bond formation between a gas molecule and the neighboring water. Compared to hardly any H-bond formation between CO2 (or O2) and the framework of the CPNT, NH3 can form abundant H-bonds with the carbonyl/amide groups of the CPNT, leading to a fierce competition to NH3-water H-bonded interactions. In addition to direct H-bonded interactions, all three gases can form water bridges with the tube. The potential profile of mean force coincides with the occurring probability of a gas molecule along the tube axis. The energy barriers at two mouths of the CPNT elucidate the phenomenon that CO2 and O2 are thoroughly confined in the narrow lumen while NH3 can easily go outside the tube. Intermolecular interactions of each gas with channel water and the CPNT framework and the formation of H-bonds and water bridges illuminate the different gas translocation behaviors. The results uncover interesting and comprehensive mechanisms underlying the permeation characteristics of three gas molecules traveling through a transmembrane CPNT.

  9. NMR structural and dynamical investigation of the isolated voltage-sensing domain of the potassium channel KvAP: implications for voltage gating.

    PubMed

    Shenkarev, Zakhar O; Paramonov, Alexander S; Lyukmanova, Ekaterina N; Shingarova, Lyudmila N; Yakimov, Sergei A; Dubinnyi, Maxim A; Chupin, Vladimir V; Kirpichnikov, Mikhail P; Blommers, Marcel J J; Arseniev, Alexander S

    2010-04-28

    The structure and dynamics of the isolated voltage-sensing domain (VSD) of the archaeal potassium channel KvAP was studied by high-resolution NMR. The almost complete backbone resonance assignment and partial side-chain assignment of the (2)H,(13)C,(15)N-labeled VSD were obtained for the protein domain solubilized in DPC/LDAO (2:1) mixed micelles. Secondary and tertiary structures of the VSD were characterized using secondary chemical shifts and NOE contacts. These data indicate that the spatial structure of the VSD solubilized in micelles corresponds to the structure of the domain in an open state of the channel. NOE contacts and secondary chemical shifts of amide protons indicate the presence of tightly bound water molecule as well as hydrogen bond formation involving an interhelical salt bridge (Asp62-R133) that stabilizes the overall structure of the domain. The backbone dynamics of the VSD was studied using (15)N relaxation measurements. The loop regions S1-S2 and S2-S3 were found mobile, while the S3-S4 loop (voltage-sensor paddle) was found stable at the ps-ns time scale. The moieties of S1, S2, S3, and S4 helices sharing interhelical contacts (at the level of the Asp62-R133 salt bridge) were observed in conformational exchange on the micros-ms time scale. Similar exchange-induced broadening of characteristic resonances was observed for the VSD solubilized in the membrane of lipid-protein nanodiscs composed of DMPC, DMPG, and POPC/DOPG lipids. Apparently, the observed interhelical motions represent an inherent property of the VSD of the KvAP channel and can play an important role in the voltage gating.

  10. 13. DETAIL OF CONNECTION BETWEEN TOP CHORD AND POST IN ...

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

    13. DETAIL OF CONNECTION BETWEEN TOP CHORD AND POST IN WEST TRUSS, SHOWING CHANNELS AND REINFORCED CAST-IRON LACING, I-BEAMS FASTENED TOGETHER WITH RIVETTED PLATES, AND ASSEMBLY OF DIAGONAL EYE BEAM AND BOLT; VIEW FROM EAST SIDE. - Mitchell's Mill Bridge, Spanning Winter's Run on Carrs Mill Road, west of Bel Air, Bel Air, Harford County, MD

  11. 76 FR 51885 - Drawbridge Operation Regulation; Grassy Sound Channel, Middle Township, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-19

    ... the past 6 years there have been minimal openings for this bridge during the morning hours in August... INFORMATION CONTACT: If you have questions on this rule, call or e-mail Lindsey Middleton, Coast Guard; telephone 757-398-6629, e-mail [email protected] . If you have questions on viewing the docket...

  12. 78 FR 26380 - Proposal To Replace the Existing Movable I-5 Bridge Across the Columbia River With a Fixed Multi...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-06

    ..., which requires agencies to coordinate and expedite the permitting and environmental review process for... by CRC to realign the federal channel to accommodate the proposed project. A ship simulation will be... provides information on how to participate in the process. The process includes an opportunity to submit...

  13. Level II scour analysis for Bridge 8 (ANDOTH00010008) on Town Highway 1, crossing Andover Branch, Andover, Vermont

    USGS Publications Warehouse

    Flynn, Robert H.; Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ANDOTH00010008 on Town Highway 1 crossing the Andover Branch, Andover , Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.The site is in the Green Mountain section of the New England physiographic province in south-central Vermont. The 5.30-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover along the immediate banks, both upstream and downstream of the bridge, is grass while farther upstream and downstream, the surface cover is primarily forest.In the study area, the Andover Branch has an incised, straight channel with a slope of approximately 0.01 ft/ft, an average channel top width of 35 ft and an average bank height of 3 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 63.6 mm (0.209 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 27, 1996, indicated that the reach was stable.The Town Highway 1 crossing of the Andover Branch is a 54-ft-long, two-lane bridge consisting of one 51-foot steel-beam span (Vermont Agency of Transportation, written communication, March 28, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the opening-skew-to-roadway is 30 degrees.A scour hole 0.7 ft deeper than the mean thalweg depth was observed approximately 52 feet downstream of the downstream face of the bridge during the Level I assessment. Scour countermeasures at the site include type-2 stone fill (less than 36 inches diameter) along the entire base length of the left and right abutments and along the left bank from 65 ft to 89 ft upstream. Type-1 stone fill was found along the right bank from the bridge to 47 ft upstream and along the left bank from 40 ft to 65 ft upstream. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled flows ranged from 0.0 to 0.1 ft. The worst case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 5.0 to 8.1 ft along the left abutment and from 2.1 to 4.6 ft along the right abutment. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  14. Level II scour analysis for Bridge 27 (WSTOTH00070027) on Town Highway 7, crossing Jenny Coolidge Brook, Weston, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure WSTOTH00070027 on Town Highway 7 crossing Jenny Coolidge Brook, Weston, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in southwestern Vermont. The 2.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture downstream of the bridge while upstream of the bridge is forested. In the study area, the Jenny Coolidge Brook has an incised, sinuous channel with a slope of approximately 0.04 ft/ft, an average channel top width of 51 ft and an average bank height of 6 ft. The channel bed material ranges from sand to boulders with a median grain size (D50) of 122 mm (0.339 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 20, 1996, indicated that the reach was stable. The Town Highway 7 crossing of the Jenny Coolidge Brook is a 52-ft-long, two-lane bridge consisting of a 50-foot steel-beam span (Vermont Agency of Transportation, written communication, April 7, 1995). The opening length of the structure parallel to the bridge face is 49.2 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 5 degrees to the opening while the computed opening-skew-to-roadway is 15 degrees. The legs of the skeleton-type right abutment were exposed approximately 2 feet (vertically) and approximately 2 feet (horizontally) during the Level I assessment. Scour protection measures at the site include type-1 stone fill (less than 12 inches diameter) along the downstream right wingwall, and type-2 stone fill (less than 36 inches diameter) along the upstream banks, upstream left wingwall, left abutment, downstream left wingwall and downstream left bank. A stone wall levee extends along the downstream right bank. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was zero ft. Abutment scour ranged from 3.0 to 4.1 ft. The worst-case left abutment scour occurred at the 100-year discharge. The worst-case right abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particlesize distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Level II scour analysis for Bridge 13 (LINCTH00010013) on Town Highway 1, crossing Cota Brook, Lincoln, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure LINCTH00010013 on Town Highway 1 crossing Cota Brook, Lincoln, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in west-central Vermont. The 3.0-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest along the upstream right bank and brushland along the upstream left bank. Downstream of the bridge, the surface cover is pasture along the left and right banks. In the study area, Cota Brook has an sinuous channel with a slope of approximately 0.01 ft/ ft, an average channel top width of 30 ft and an average bank height of 2 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 34.7 mm (0.114 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 10, 1996, indicated that the reach was laterally unstable due to cut-banks and wide, vegetated point bars upstream and downstream of the bridge. The Town Highway 1 crossing of Cota Brook is a 38-ft-long, two-lane bridge consisting of a 36-foot steel-stringer span (Vermont Agency of Transportation, written communication, December 14, 1995). The opening length of the structure parallel to the bridge face is 34.4 ft. The bridge is supported by vertical, concrete abutments. The channel is skewed approximately 15 degrees to the opening while the opening-skew-to-roadway is zero degrees.A scour hole 2.0 ft deeper than the mean thalweg depth was observed along the upstream right bank during the Level I assessment. Along the right abutment, it is 0.25 ft deeper than the mean thalweg depth. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) along the upstream right bank and type-2 stone fill (less than 36 inches diameter) along the left and right abutments and along the downstream left bank. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 1.7 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 9.1 to 11.3 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  16. Level II scour analysis for Bridge 7H (HUNTTH0001007H) on Town Highway 1, crossing Cobb Brook, Huntington, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure HUNTTH001007H on Town Highway 1 crossing the Cobb Brook, Huntington, Vermont (figures 1–10). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.In August 1976, Hurricane Belle caused flooding at this site which resulted in road and bridge damage (figures 7-8). This was approximately a 25-year flood event (U.S. Department of Housing and Urban Development, 1978). The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 4.20-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream of the bridge. Downstream of the bridge is brushland and pasture.In the study area, the Cobb Brook has an incised, straight channel with a slope of approximately 0.03 ft/ft, an average channel top width of 43 ft and an average bank height of 6 ft. The channel bed material ranges from sand to boulders with a median grain size (D50) of 65.5 mm (0.215 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 24, 1996, indicated that the reach was stable. The Town Highway 1 crossing of the Cobb Brook is a 23-ft-long, two-lane bridge consisting of one 20-foot concrete slab span (Vermont Agency of Transportation, written communication, June 21, 1996). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 15 degrees to the opening while the opening-skew-to-roadway is zero degrees.A scour hole 2.8 ft deeper than the mean thalweg depth was observed along the left abutment during the Level I assessment. Protection measures at the site include type-1 stone fill (less than 12 inches diameter) at the downstream right wingwall, type-2 stone fill (less than 36 inches diameter) at the upstream right wingwall and the downstream end of the downstream left wingwall, and type-3 stone fill (less than 48 inches diameter) at the upstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled flows ranged from 0.2 to 1.3 ft. The worst-case contraction scour occurred at the incipient-overtopping discharge. Abutment scour ranged from 4.0 to 8.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 10. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  17. Level II scour analysis for Bridge 33 (CONCTH00580033) on Town Highway 58, crossing Miles Stream, Concord, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure CONCTH00580033 on Town Highway 58 crossing Miles Stream, Concord, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in northeastern Vermont. The 17.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream of the bridge while the immediate banks have dense woody vegetation. Downstream of the bridge, the right bank is forested and the left bank has shrubs and brush. In the study area, Miles Stream has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 91 ft and an average bank height of 7 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 61.6 mm (0.188 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 15, 1995, indicated that the reach was stable. The Town Highway 58 crossing of Miles Stream is a 44-ft-long, two-lane bridge consisting of one 39-foot steel-beam span (Vermont Agency of Transportation, written communication, March 24, 1995). The opening length of the structure parallel to the bridge face is 37.4 ft. The bridge is supported by vertical, concrete abutments with stone fill in front creating spillthrough embankments. The channel is skewed approximately 20 degrees to the opening while the opening-skew-to-roadway is zero degrees. The only scour countermeasure at the site was type-3 stone fill (less than 48 inches diameter) along the left and right banks upstream, in front of the abutments forming spill through embankments, and extending along the banks downstream. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 1.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 4.0 to 9.7 ft. The worst-case abutment scour occurred at the 500-year discharge for the right abutment and at the incipient roadway-overtopping discharge for the left abutment. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  18. Level II scour analysis for Bridge 46 (FFIETH00470046) on Town Highway 47, crossing Black Creek, Fairfield, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Flynn, Robert H.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure FFIETH00470046 on Town Highway 47 crossing Black Creek, Fairfield, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gathered from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in northwestern Vermont. The 37.8 mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge while the immediate banks have dense woody vegetation. In the study area, Black Creek has a meandering channel with a slope of approximately 0.0005 ft/ft, an average channel top width of 51 ft and an average bank height of 6 ft. The channel bed material ranges from sand to bedrock with a median grain size (D50) of 0.189 mm (0.00062 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 12, 1995, indicated that the reach was stable. The Town Highway 47 crossing of Black Creek is a 35-ft-long, one-lane bridge consisting of one 31-ft steel-stringer span (Vermont Agency of Transportation, written communication, March 8, 1995). The opening length of the structure parallel to the bridge face is 28.0 ft. The bridge is supported by vertical, laid-up stone abutments with wingwalls. The channel is skewed approximately zero degrees to the opening and the opening-skew-toroadway is zero degrees. A scour hole 6.0 ft deeper than the mean thalweg depth was observed just downstream of the bridge during the Level I assessment. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) along the left abutment. Type-2 stone fill (less than 36 inches diameter) extended along the upstream left and right banks, the upstream left and right wingwalls, the downstream left wingwall, and the downstream left bank. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.4 to 8.2 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was less than the 100-year discharge. Abutment scour ranged from 5.8 to 15.6 ft. At the left abutment, the worst-case abutment scour occurred at the 100-year discharge, and at the right abutment the worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results.” Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  19. Preliminary assessment of channel stability and bed-material transport along Hunter Creek, southwestern Oregon

    USGS Publications Warehouse

    Jones, Krista L.; Wallick, J. Rose; O'Connor, Jim E.; Keith, Mackenzie K.; Mangano, Joseph F.; Risley, John C.

    2011-01-01

    This preliminary assessment of (1) bed-material transport in the Hunter Creek basin, (2) historical changes in channel condition, and (3) supplementary data needed to inform permitting decisions regarding instream gravel extraction revealed the following: Along the lower 12.4 km (kilometers) of Hunter Creek from its confluence with the Little South Fork Hunter Creek to its mouth, the river has confined and unconfined segments and is predominately alluvial in its lowermost 11 km. This 12.4-km stretch of river can be divided into two geomorphically distinct study reaches based primarily on valley physiography. In the Upper Study Reach (river kilometer [RKM] 12.4-6), the active channel comprises a mixed bed of bedrock, boulders, and smaller grains. The stream is confined in the upper 1.4 km of the reach by a bedrock canyon and in the lower 2.4 km by its valley. In the Lower Study Reach (RKM 6-0), where the area of gravel bars historically was largest, the stream flows over bed material that is predominately alluvial sediments. The channel alternates between confined and unconfined segments. The primary human activities that likely have affected bed-material transport and the extent and area of gravel bars are (1) historical and ongoing aggregate extraction from gravel bars in the study area and (2) timber harvest and associated road construction throughout the basin. These anthropogenic activities likely have varying effects on sediment transport and deposition throughout the study area and over time. Although assessing the relative effects of these anthropogenic activities on sediment dynamics would be challenging, the Hunter Creek basin may serve as a case study for such an assessment because it is mostly free of other alterations to hydrologic and geomorphic processes such as flow regulation, dredging, and other navigation improvements that are common in many Oregon coastal basins. Several datasets are available that may support a more detailed physical assessment of Hunter Creek. The entire study area has been captured in aerial photographs at least once per decade since the 1940s. This temporally rich photograph dataset would support quantitative analyses of changes in channel planform as well as vegetation cover. Light Detection And Ranging (LiDAR) data collected in 2008 would facilitate hydraulic and sediment-transport modeling and characterization of bar elevations throughout most of the study area. Few studies describing channel morphology and sediment transport exist for the Hunter Creek basin. The most detailed study reported channel incision and bank instability as well as the loss of point bars and pools in the lower 3.9 km of Hunter Creek from slightly downstream of its confluence with Yorke Creek to its mouth (EA Engineering, Sci-ence, and Technology, 1998). Repeat channel cross-sections collected from 1994 to 2010 at four bridges indicate that Hunter Creek is dynamic and subject to channel shifting, aggradation, and incision. Despite this dynamism, the channel at three bridge crossings showed little net change in thalweg elevation during this period. However, the channel thalweg aggraded 0.55 m from 2004 to 2008 near the bridge at RKM 3.5. Systematic delineation of gravel bars from aerial photographs collected in 1940, 1965, 2005, and 2009 indicates a 52-percent reduction in the area of bed-material sediment throughout the study area from 1940 to 2009. Net bar loss was greatest in the Lower Study Reach from RKM 1-4 and mainly is associ-ated with the encroachment of vegetation onto upper-bar surfaces lacking apparent vegetation in 1940. Bar-surface material was approximately equal in size to bar-subsurface material at Conn Creek Bar, whereas it was distinctly coarser than the subsurface material at Menasha Bar. Armoring ratios, which indicate the coarseness of the bar surface relative to the bar subsurface, were calculated as 0.97 for Conn Creek Bar and 1.5 for Menasha Bar. These ratios tentatively show that

  20. In-channel electrochemical detection in the middle of microchannel under high electric field.

    PubMed

    Kang, Chung Mu; Joo, Segyeong; Bae, Je Hyun; Kim, Yang-Rae; Kim, Yongseong; Chung, Taek Dong

    2012-01-17

    We propose a new method for performing in-channel electrochemical detection under a high electric field using a polyelectrolytic gel salt bridge (PGSB) integrated in the middle of the electrophoretic separation channel. The finely tuned placement of a gold working electrode and the PGSB on an equipotential surface in the microchannel provided highly sensitive electrochemical detection without any deterioration in the separation efficiency or interference of the applied electric field. To assess the working principle, the open circuit potentials between gold working electrodes and the reference electrode at varying distances were measured in the microchannel under electrophoretic fields using an electrically isolated potentiostat. In addition, "in-channel" cyclic voltammetry confirmed the feasibility of electrochemical detection under various strengths of electric fields (∼400 V/cm). Effective separation on a microchip equipped with a PGSB under high electric fields was demonstrated for the electrochemical detection of biological compounds such as dopamine and catechol. The proposed "in-channel" electrochemical detection under a high electric field enables wider electrochemical detection applications in microchip electrophoresis.

  1. Activation of acid-sensing ion channels by localized proton transient reveals their role in proton signaling

    PubMed Central

    Zeng, Wei-Zheng; Liu, Di-Shi; Liu, Lu; She, Liang; Wu, Long-Jun; Xu, Tian-Le

    2015-01-01

    Extracellular transients of pH alterations likely mediate signal transduction in the nervous system. Neuronal acid-sensing ion channels (ASICs) act as sensors for extracellular protons, but the mechanism underlying ASIC activation remains largely unknown. Here, we show that, following activation of a light-activated proton pump, Archaerhodopsin-3 (Arch), proton transients induced ASIC currents in both neurons and HEK293T cells co-expressing ASIC1a channels. Using chimera proteins that bridge Arch and ASIC1a by a glycine/serine linker, we found that successful coupling occurred within 15 nm distance. Furthermore, two-cell sniffer patch recording revealed that regulated release of protons through either Arch or voltage-gated proton channel Hv1 activated neighbouring cells expressing ASIC1a channels. Finally, computational modelling predicted the peak proton concentration at the intercellular interface to be at pH 6.7, which is acidic enough to activate ASICs in vivo. Our results highlight the pathophysiological role of proton signalling in the nervous system. PMID:26370138

  2. Dynamics of protein-protein interactions at the MscL periplasmic-lipid interface.

    PubMed

    Zhong, Dalian; Yang, Li-Min; Blount, Paul

    2014-01-21

    MscL, the highly conserved bacterial mechanosensitive channel of large conductance, is one of the best studied mechanosensors. It is a homopentameric channel that serves as a biological emergency release valve that prevents cell lysis from acute osmotic stress. We previously showed that the periplasmic region of the protein, particularly a single residue located at the TM1/periplasmic loop interface, F47 of Staphylococcus aureus and I49 of Escherichia coli MscL, plays a major role in both the open dwell time and mechanosensitivity of the channel. Here, we introduced cysteine mutations at these sites and found they formed disulfide bridges that decreased the channel open dwell time. By scanning a likely interacting domain, we also found that these sites could be disulfide trapped by addition of cysteine mutations in other locations within the periplasmic loop of MscL, and this also led to rapid channel kinetics. Together, the data suggest structural rearrangements and protein-protein interactions that occur within this region upon normal gating, and further suggest that locking portions of the channel into a transition state decreases the stability of the open state. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. A study to estimate the fate and transport of bacteria in river water from birds nesting under a bridge.

    PubMed

    Nayamatullah, M M M; Bin-Shafique, S; Sharif, H O

    2013-01-01

    To investigate the effect of input parameters, such as the number of bridge-dwelling birds, decay rate of the bacteria, flow at the river, water temperature, and settling velocity, a parametric study was conducted using a water quality model developed with QUAL2Kw. The reach of the bacterial-impaired section from the direct droppings of bridge-nesting birds at the Guadalupe River near Kerrville, Texas was estimated using the model. The concentration of Escherichia coli bacteria were measured upstream, below the bridge, and downstream of the river for one-and-a-half years. The decay rate of the indicator bacteria in the river water was estimated from the model using measured data, and was found to be 6.5/day. The study suggests that the number of bridge-dwelling birds, the decay rate, and flow at the river have the highest impact on the fate and transport of bacteria. The water temperature moderately affects the fate and transport of bacteria, whereas, the settling velocity of bacteria did not show any significant effect. Once the decay rates are estimated, the reach of the impaired section was predicted from the model using the average flow of the channel. Since the decay rate does not vary significantly in the ambient environment at this location, the length of the impaired section primarily depends on flow.

  4. Floods in mountain environments: A synthesis

    NASA Astrophysics Data System (ADS)

    Stoffel, Markus; Wyżga, Bartłomiej; Marston, Richard A.

    2016-11-01

    Floods are a crucial agent of geomorphic change in the channels and valley floors of mountains watercourses. At the same time, they can be highly damaging to property, infrastructure, and life. Because of their high energy, mountain watercourses are highly vulnerable to environmental changes affecting their catchments and channels. Many factors have modified and frequently still tend to modify the environmental conditions in mountain areas, with impacts on geomorphic processes and the frequency, magnitude, and timing of floods in mountain watercourses. The ongoing climate changes vary between regions but may affect floods in mountain areas in many ways. In many mountain regions of Europe, widespread afforestation took place over the twentieth century, considerably increasing the amounts of large wood delivered to the channels and the likelihood of jamming bridges. At the same time, deforestation continues in other mountain areas, accelerating runoff and amplifying the magnitude and frequency of floods in foreland areas. In many countries, in-channel gravel mining has been a common practice during recent decades; the resultant deficit of bed material in the affected channels may suddenly manifest during flood events, resulting in the failure of scoured bridges or catastrophic channel widening. During the past century many rivers in mountain and foreland areas incised deeply; the resultant loss of floodplain water storage has decreased attenuation of flood waves, hence increasing flood hazard to downstream river reaches. On the other hand, a large amount of recent river restoration activities worldwide may provide examples of beneficial changes to flood risk, attained as a result of increased channel storage or reestablished floodplain water storage. Relations between geomorphic processes and floods operate in both directions, which means that changes in flood probability or the character of floods (e.g., increased wood load) may significantly modify the morphology of mountain rivers, but morphological changes of rivers can also affect hydrological properties of floods and the associated risk for societies. This paper provides a review of research in the field of floods in mountain environments and puts the papers of this special issue dedicated to the same topic into context. It also provides insight into innovative studies, methods, or emerging aspects of the relations between environmental changes, geomorphic processes, and the occurrence of floods in mountain rivers.

  5. 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 hydrologic, sedimentary, and anthropogenic controls. Since the 1960s, numerous point bars have vertically accreted and vegetation has encroached along the channel margins, which probably promotes channel-bed incision to compensate for a reduction in cross-sectional area. Channel incision was detected at all gaging stations along the Brazos River, and the depth of incision is greatest in the lowermost gaging stations, exemplified by about 5 feet of channel-bed incision between 1993 and 2004 at Richmond, Texas. One notable exception to this pattern of incision was a period of aggradation at U.S. Geological Survey gaging station 08096500 Brazos River at Waco, Texas, during the late 1920s and 1930s, probably associated with upstream dam construction. Lateral channel migration rates along the Brazos River determined from aerial photographs are greatest between Waco and Hempstead, Texas, with numerous bends moving an average of more than 10 feet per year. Migration rates at selected bends downstream from Hempstead were measured as less than 10 feet per year, on average. Two tributaries of the Brazos River, the Little and Navasota Rivers, also were investigated for historical channel adjustment. The Little River near Cameron, Texas (08106500) has incised its channel bed about 12 feet since 1949, and the lower Navasota River shows complex adjustment to bridge construction activities and a channel avulsion.

  6. Cross correlation measurement of low frequency conductivity noise

    NASA Astrophysics Data System (ADS)

    Jain, Aditya Kumar; Nigudkar, Himanshu; Chakraborti, Himadri; Udupa, Aditi; Gupta, Kantimay Das

    2018-04-01

    In order to study the low frequency noise(1/f noise)an experimental technique based on cross correlation of two channels is presented. In this method the device under test (DUT)is connected to the two independently powered preamplifiers in parallel. The amplified signals from the two preamplifiers are fed to two channels of a digitizer. Subsequent data processing largelyeliminates the uncorrelated noise of the two channels. This method is tested for various commercial carbon/metal film resistors by measuring equilibrium thermal noise (4kBTR). The method is then modified to study the non-equilibrium low frequency noise of heterostructure samples using fiveprobe configuration. Five contact probes allow two parts of the sample to become two arms of a balanced bridge. This configuration helps in suppressing the effect of power supply fluctuations, bath temperature fluctuations and contact resistances.

  7. 5. Downstream elevation, view to southeast. Dark stains on side ...

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

    5. Downstream elevation, view to southeast. Dark stains on side of main girder are from deck drain scuppers, marking deck level within the girders. Compare this view and CA-126-7 to CA-126-19 for indication of severity of siltation of Salt River channel has silted. - Salt River Bridge, Spanning Salt River at Dillon Road, Ferndale, Humboldt County, CA

  8. Use of antibodies specific to defined regions of scorpion. cap alpha. -toxin to study its interaction with its receptor site on the sodium channel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ayeb, M.E.; Bahraoui, E.M.; Granier, C.

    1986-10-21

    Five antibody populations selected by immunoaffinity chromatography for the specificity toward various regions of toxin II of the scorpion Androctonus australis Hector were used to probe the interaction of this protein with its receptor site on the sodium channel. These studies indicate that two antigenic sites, one located around the disulfide bridge 12-63 and one encompassing residues 50-59, are involved in the molecular mechanisms of toxicity neutralization. Fab fragments specific to the region around disulfide bridge 12-63 inhibit binding of the /sup 125/I-labeled toxin to its receptor site. Also, these two antigenic regions are inaccessible to the antibodies when themore » toxin is bound to its receptor site. In contrast, the two other antigenic sites encompassing the only ..cap alpha..-helix region (residues 23-32) and a ..beta..-turn structure (residues 32-35) are accessible to the respective antibodies when the toxin is bound to its receptor. Together, these data support the recent proposal that a region made of residues that are conserved in the scorpion toxin family is involved in the binding of the toxin to the receptor.« less

  9. DICOM relay over the cloud.

    PubMed

    Silva, Luís A Bastião; Costa, Carlos; Oliveira, José Luis

    2013-05-01

    Healthcare institutions worldwide have adopted picture archiving and communication system (PACS) for enterprise access to images, relying on Digital Imaging Communication in Medicine (DICOM) standards for data exchange. However, communication over a wider domain of independent medical institutions is not well standardized. A DICOM-compliant bridge was developed for extending and sharing DICOM services across healthcare institutions without requiring complex network setups or dedicated communication channels. A set of DICOM routers interconnected through a public cloud infrastructure was implemented to support medical image exchange among institutions. Despite the advantages of cloud computing, new challenges were encountered regarding data privacy, particularly when medical data are transmitted over different domains. To address this issue, a solution was introduced by creating a ciphered data channel between the entities sharing DICOM services. Two main DICOM services were implemented in the bridge: Storage and Query/Retrieve. The performance measures demonstrated it is quite simple to exchange information and processes between several institutions. The solution can be integrated with any currently installed PACS-DICOM infrastructure. This method works transparently with well-known cloud service providers. Cloud computing was introduced to augment enterprise PACS by providing standard medical imaging services across different institutions, offering communication privacy and enabling creation of wider PACS scenarios with suitable technical solutions.

  10. Basic hydraulic principles of open-channel flow

    USGS Publications Warehouse

    Jobson, Harvey E.; Froehlich, David C.

    1988-01-01

    The three basic principles of open-channel-flow analysis--the conservation of mass, energy, and momentum--are derived, explained, and applied to solve problems of open-channel flow. These principles are introduced at a level that can be comprehended by a person with an understanding of the principles of physics and mechanics equivalent to that presented in the first college level course of the subject. The reader is assumed to have a working knowledge of algebra and plane geometry as well as some knowledge of calculus. Once the principles have been derived, a number of example applications are presented that illustrate the computation of flow through culverts and bridges, and over structures, such as dams and weirs. Because resistance to flow is a major obstacle to the successful application of the energy principle to open-channel flow, procedures are outlined for the rational selection of flow resistance coefficients. The principle of specific energy is shown to be useful in the prediction of water-surface profiles both in the qualitative and quantitative sense. (USGS)

  11. Measuring flood discharge in unstable stream channels using ground-penetrating radar

    USGS Publications Warehouse

    Spicer, K.R.; Costa, J.E.; Placzek, G.

    1997-01-01

    Field experiments were conducted to test the ability of ground-penetrating radar (GPR) to measure stream-channel cross sections at high flows without the necessity of placing instruments in the water. Experiments were conducted at four U.S. Geological Survey gaging stations in southwest Washington State. With the GPR antenna suspended above the water surface from a bridge or cableway, traverses were made across stream channels to collect radar profile plots of the streambed. Subsequent measurements of water depth were made using conventional depth-measuring equipment (weight and tape) and were used to calculate radar signal velocities. Other streamflow-parameter data were collected to examine their relation to radar signal velocity and to claritv of streambed definition. These initial tests indicate that GPR is capable of producing a reasonably accurate (??20%) stream-channel profile and discharge far more quickly than conventional stream-gaging procedures, while avoiding the problems and hazards associated with placing instruments in the water.

  12. Design of high-energy high-current linac with focusing by superconducting solenoids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Batskikh, G.I.; Belugin, V.M.; Bondarev, B.I.

    1995-10-01

    The advancement of MRTI design for 1.5 GeV and 250 mA ion CW linac was presented in a previous report. In this new linac version all the way from input to output the ions are focused by magnetic fields of superconducting solenoids. The ion limit current is far beyond the needed value. The linac focusing channel offers major advantages over the more conventional ones. The acceptance is 1.7 times as large for such focusing channel as for quadrupole one. Concurrently, a random perturbation sensitivity for such channel is one order of magnitude smaller than in quadrupole channel. These focusing channelmore » features allow to decrease beam matched radius and increase a linac radiation purity without aperture growth. {open_quotes}Regotron{close_quotes} is used as high power generator in linac main part. But D&W cavities need not be divided into sections connected by RF-bridges which denuded them of high coupling factor.« less

  13. Packaging and testing of multi-wavelength DFB laser array using REC technology

    NASA Astrophysics Data System (ADS)

    Ni, Yi; Kong, Xuan; Gu, Xiaofeng; Chen, Xiangfei; Zheng, Guanghui; Luan, Jia

    2014-02-01

    Packaging of distributed feedback (DFB) laser array based on reconstruction-equivalent-chirp (REC) technology is a bridge from chip to system, and influences the practical process of REC chip. In this paper, DFB laser arrays of 4-channel @1310 nm and 8-channel @1550 nm are packaged. Our experimental results show that both these laser arrays have uniform wavelength spacing and larger than 35 dB average Side Mode Suppression Ratio (SMSR). When I=35 mA, we obtain the total output power of 1 mW for 4-channel @1310 nm, and 227 μw for 8-channel @1550 nm respectively. The high frequency characteristics of the packaged chips are also obtained, and the requirements for 4×10 G or even 8×10 G systems can be reached. Our results demonstrate the practical and low cost performance of REC technology and indicate its potential in the future fiber-to-the-home (FTTH) application.

  14. Level II scour analysis for Bridge 34 (ROCHTH00210034) on Town Highway 21, crossing the White River, Rochester, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Degnan, James

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ROCHTH00210034 on Town Highway 21 crossing the White River, Rochester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, obtained from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 74.8-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is suburban on the upstream and downstream left overbanks, though brush prevails along the immediate banks. On the upstream and downstream right overbanks, the surface cover is pasture with brush and trees along the immediate banks.In the study area, the White River has an incised, straight channel with a slope of approximately 0.002 ft/ft, an average channel top width of 102 ft and an average bank height of 5 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 74.4 mm (0.244 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 23, 1996, indicated that the reach was stable.The Town Highway 21 crossing of the White River is a 72-ft-long, two-lane bridge consisting of 70-foot steel stringer span (Vermont Agency of Transportation, written communication, March 22, 1995). The opening length of the structure parallel to the bridge face is 67.0 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 15 degrees to the opening while the opening-skew-to-roadway is zero degrees.Channel scour, 1.5 ft deeper than the mean thalweg depth was observed along the left abutment and wingwalls during the Level I assessment. Scour countermeasures at the site includes type-1 stone fill (less than 12 inches diameter) along the upstream left bank and the upstream and downstream left road embankments, type-2 (less than 36 inches diameter) along the upstream end of the upstream left wingwall and downstream left bank, and type-3 (less than 48 inches diameter) along the downstream end of the downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). In addition, the incipient roadway-overtopping discharge is analyzed since it has the potential of being the worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled discharges was zero. Left abutment scour ranged from 6.8 to 21.2 ft. Right abutment scour ranged from 13.9 to 18.4 ft. The worst-case abutment scour occurred at the 500-year discharge at the left and right abutments. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Level II scour analysis for Bridge 38 (JERITH0020038) on Town Highway 20, crossing the Lee River, Jericho, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Degnan, James R.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure JERITH00200038 on Town Highway 20 crossing the Lee River, Jericho, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, obtained from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province and the Champlain section of the St. Lawrence physiographic province in northwestern Vermont. The 12.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover on the upstream and downstream right overbank is pasture while the immediate banks have dense woody vegetation. The surface cover on the upstream and downstream left overbank is forested. In the study area, the Lee River has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 89 ft and an average bank height of 14 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 45.9 mm (0.151 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 2, 1996, indicated that the reach was stable. The Town Highway 20 crossing of the Lee River is a 49-ft-long, one-lane bridge consisting of a steel through truss span (Vermont Agency of Transportation, written communication, December 12, 1995). The opening length of the structure parallel to the bridge face is 44 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the computed opening-skew-toroadway is 5 degrees. A scour hole 1 ft deeper than the mean thalweg depth was observed in the center of the channel during the Level I assessment. Scour countermeasures at the site include type-1 stone fill (less than 12 inches diameter) at the downstream left road embankment. Type-2 stone fill (less than 36 inches diameter) protects the upstream left wingwall, the upstream and downstream right wingwalls and the upstream end of the right abutment. Type-3 stone fill (less than 48 inches diameter) protects the left abutment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was zero. Abutment scour ranged from 4.9 to 10.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  16. Level II scour analysis for Bridge 16 (RIPTTH00110016) on Town Highway 11, crossing the Middle Branch Middlebury River, Ripton, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure RIPTTH00110016 on Town Highway 11 crossing the Middle Branch Middlebury River, Ripton, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in west-central Vermont. The 6.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover consists of shrubs, brush and trees except for the upstream left bank which is completely forested. In the study area, the Middle Branch Middlebury River has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 68 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 97.6 mm (0.320 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 11, 1996, indicated that the reach was stable. The Town Highway 11 crossing of the Middle Branch Middlebury River is a 44-ft-long, two-lane bridge consisting of one 42-foot steel-beam span (Vermont Agency of Transportation, written communication, December 15, 1995). The opening length of the structure parallel to the bridge face is 40.2 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 40 degrees to the opening. The opening-skew-to-roadway value from the VTAOT database is 20 degrees while 30 degrees was computed from surveyed points. A scour hole, 3 ft deeper than the mean thalweg depth, was observed along the left abutment and upstream left wingwall during the Level I assessment. In addition, 1 ft of channel scour was observed just downstream of the downstream left wingwall along the left bank. Scour countermeasures at the site included type-2 stone fill (less than 36 inches diameter) along the upstream left and right banks and along the upstream end of the downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.1 to 0.4 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 7.2 to 8.6 ft along the right abutment and from 11.7 to 13.7 ft along the left abutment. The worstcase abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  17. Level II scour analysis for Bridge 144 (ROCHVT01000144) on State Route 100, crossing the White River, Rochester, Vermont

    USGS Publications Warehouse

    Boehmler, Erick M.; Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ROCHVT01000144 on State Route 100 crossing the White River, Rochester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 68.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture with forest on the valley walls. In the study area, the White River has a meandering channel with a slope of approximately 0.003 ft/ft, an average channel top width of 119 ft and an average channel depth of 4 ft. The predominant channel bed material is gravel and cobbles with a median grain size (D50) of 72.5 mm (0.238 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 22, 1996, indicated that the reach was laterally unstable due to a cut-bank present on the upstream left bank and wide point bars upstream and downstream in the vicinity of this site. The State Route 100 crossing of the White Riveris a 103-ft-long, two-lane bridge consisting of one 101-foot steel-beam span (Vermont Agency of Transportation, written communication, March 8, 1995). The bridge is supported by vertical, concrete abutment walls with spill-through embankments in front of each abutment wall and no wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening-skew-toroadway is 5 degrees. The scour protection measures at the site are type-2 stone fill (less than 36 inches diameter) on the upstream left bank, both abutment spill-through embankments, and the downstream banks. There also is type-1 stone fill (less than 12 inches diameter) on the upstream right bank. The stone fill is continuous on both sides of the river in the vicinity of the bridge. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. There was no computed contraction scour for the modelled flows. Abutment scour ranged from 6.9 to 10.9 ft. The worst-case abutment scour occurred at the incipient overtopping discharge, which was less than the 100-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particlesize distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  18. Level II scour analysis for Bridge 4 (MAIDTH00070004) on Town Highway 7, crossing Cutler Mill Brook, Maidstone, Vermont

    USGS Publications Warehouse

    Striker, Lora K.; Medalie, Laura

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure MAIDTH00070004 on Town Highway 7 crossing the Cutler Mill Brook, Maidstone, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the White Mountain section of the New England physiographic province in northeastern Vermont. The 18.1-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is predominantly shrub and brushland. In the study area, the Cutler Mill Brook has a non-incised, meandering channel with local braiding and a slope of approximately 0.004 ft/ft, an average channel top width of 43 ft and an average bank height of 2 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 27.6 mm (0.091 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 19, 1995, indicated that the reach was laterally unstable due to large meanders in the channel. The Town Highway 7 crossing of the Cutler Mill Brook is a 25-ft-long, one-lane bridge consisting of one 22-foot concrete span (Vermont Agency of Transportation, written communication, August 5, 1994). The opening length of the structure parallel to the bridge face is 21.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 20 degrees to the opening while the opening-skew-to-roadway is 0 degrees. A scour hole 2.0 ft deeper than the mean thalweg depth was observed along the left abutment during the Level I assessment. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along both banks upstream, along the entire base length of the upstream left wingwall, and along the upstream end of the upstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 2.2 to 4.2 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 5.7 to 12.4 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  19. Level II scour analysis for Bridge 12 (HUNTTH00010012) on Town Highway 001, crossing Brush Brook, Huntington, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Wild, Emily C.

    1997-01-01

    frequency data contained in the Flood Insurance Study for the Town of Huntington (U.S. Department of Housing and Urban Development, 1978). The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 9.19-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture while the immediate banks have some woody vegetation. In the study area, the Brush Brook has a sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 62 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to cobble with a median grain size (D50) of 100.0 mm (0.328 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 25, 1996, indicated that the reach was stable. The Town Highway 1 crossing of Brush Brook is a 64-ft-long, two-lane bridge consisting of one 62-foot steel-stringer span (Vermont Agency of Transportation, written communication, November 30, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is 6 degrees. Channel scour 2.2 ft deeper than the mean thalweg depth was observed along the upstream right bank and along the base of the spill-through protection for the right abutment during the Level I assessment. Scour protection measured at the site was type-2 stone fill (less than 36 inches diameter) along the upstream left and right banks and in front of all four wingwalls. In front of the abutments, there was type-3 stone fill (less than 48 inches diameter) forming a spill-through slope. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. There was no computed contraction scour for any modelled flow. Abutment scour ranged from 1.4 to 2.8 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 9. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  20. Geomorphology of the lower Copper River, Alaska

    USGS Publications Warehouse

    Brabets, T.P.

    1996-01-01

    The Copper River, located in southcentral Alaska, drains an area of more than 24,000 square miles. About 30 miles above its mouth, this large river enters Miles Lake, a proglacial lake formed by the retreat of Miles Glacier. Downstream from the outlet of Miles Lake, the Copper River flows past the face of Childs Glacier before it enters a large, broad, alluvial flood plain. The Copper River Highway traverses this flood plain and in 1996, 11 bridges were located along this section of the highway. These bridges cross parts or all of the Copper River and in recent years, some of these bridges have sustained serious damage due to the changing course of the Copper River. Although the annual mean discharge of the lower Copper River is 57,400 cubic feet per second, most of the flow occurs during the summer months from snowmelt, rainfall, and glacial melt. Approximately every six years, an outburst flood from Van Cleve Lake, a glacier-dammed lake formed by Miles Glacier, releases approximately 1 million acre-feet of water into the Copper River. At the peak outflow rate from Van Cleve Lake, the flow of the Copper River will increase an additional 140,000 and 190,000 cubic feet per second. Bedload sampling and continuous seismic reflection were used to show that Miles Lake traps virtually all the bedload being transported by the Copper River as it enters the lake from the north. The reservoir-like effect of Miles Lake results in the armoring of the channel of the Copper River downstream from Miles Lakes, past Childs Glacier, until it reaches the alluvial flood plain. At this point, bedload transport begins again. The lower Copper River transports 69 million tons per year of suspended sediment, approximately the same quantity as the Yukon River, which drains an area of more than 300,000 square miles. By correlating concurrent flows from a long-term streamflow- gaging station on the Copper River with a short-term streamflow-gaging station at the outlet of Miles Lake, long-term flow characteristics of the lower Copper River were synthesized. Historical discharge and cross-section data indicate that as late as 1970, most of the flow of the lower Copper River was through the first three bridges of the Copper River Highway as it begins to traverse the alluvial flood plain. In the mid 1980's, a percentage of the flow had shifted away from these three bridges and in 1995, only 51 percent of the flow of the Copper River passed through them. Eight different years of aerial photography of the lower Copper River were analyzed using Geographical Information System techniques. This analysis indicated that no major channel changes were caused by the 1964 earthquake. A flood in 1981 that had a recurrence interval of more than 100 years caused significant channel changes in the lower Copper River. A probability analysis of the lower Copper River indicated stable areas and the long-term locations of channels. By knowing the number of times a particular area has been occupied by water and the last year an area was occupied by water, areas of instability can be located. A Markov analysis of the lower Copper River indicated that the tendency of the flood plain is to remain in its current state. Large floods of the magnitude of the 1981 event are believed to be the cause of major changes in the lower Copper River.

  1. Geomorphology of the lower Copper River, Alaska

    USGS Publications Warehouse

    Brabets, Timothy P.

    1997-01-01

    The Copper River, located in southcentral Alaska, drains an area of more than 24,000 square miles. About 30 miles above its mouth, this large river enters Miles Lake, a proglacial lake formed by the retreat of Miles Glacier. Downstream from the outlet of Miles Lake, the Copper River flows past the face of Childs Glacier before it enters a large, broad, alluvial flood plain. The Copper River Highway traverses this flood plain and in 1995, 11 bridges were located along this section of the highway. These bridges cross parts of the Copper River and in recent years, some of these bridges have sustained serious damage due to the changing course of the Copper River. Although the annual mean discharge of the lower Copper River is 57,400 cubic feet per second, most of the flow occurs during the summer months from snowmelt, rainfall, and glacial melt. Approximately every six years, an outburst flood from Van Cleve Lake, a glacier-dammed lake formed by Miles Glacier, releases approximately 1 million acre-feet of water into the Copper River. When the outflow rate from Van Cleve Lake reaches it peak, the flow of the Copper River will increase between 150,000 to 190,000 cubic feet per second. Data collected by bedload sampling and continuous seismic reflection indicated that Miles Lake traps virtually all the bedload being transported by the Copper River as it enters the lake from the north. The reservoir-like effect of Miles Lake results in the armoring of the channel of the Copper River downstream from Miles Lake, past Childs Glacier, until it reaches the alluvial flood plain. At this point, bedload transport begins again. The lower Copper River transports 69 million tons per year of suspended sediment, approximately the same quantity as the Yukon River, which drains an area of more than 300,000 square miles. By correlating concurrent flows from a long-term streamflow-gaging station on the Copper River with a short-term streamflow-gaging station at the outlet of Miles Lake, long-term flow characteristics of the lower Copper River were synthesized. Historical discharge and cross-section data indicate that as late as 1970, most of the flow of the lower Copper River was through the first three bridges of the Copper River Highway as it begins to traverse the alluvial flood plain. In the mid 1980's, a percentage of the flow had shifted away from these three bridges and in 1995, only 51 percent of the flow of the Copper River passed through them. Eight different years of aerial photography of the lower Copper River were analyzed using Geographical Information System techniques. This analysis indicated that no major channel changes were caused by the 1964 earthquake. However, a flood in 1981 that had a recurrence interval of more than 100 years caused significant channel changes in the lower Copper River. A probability analysis of the lower Copper River indicated stable areas and the long-term locations of channels. By knowing the number of times a particular area has been occupied by water and the last year an area was occupied by water, areas of instability can be located. A Markov analysis of the lower Copper River indicated that the tendency of the flood plain is to remain in its current state. Large floods of the magnitude of the 1981 event are believed to be the cause of major changes in the lower Copper River.

  2. [Bridge role of Jingming (BL 1) for VDT asthenopia and brainfag based on human instinct].

    PubMed

    Zhang, Wei; Li, Huanan; Zhao, Na; Hai, Xinghua; Dong, Hua; Wang, Jingui

    2017-01-12

    To explore the bridge role of Jingming (BL 1) for video display terminal (VDT) asthenopia and brainfag. Ancient literature and modern scientific research on the acupoint have been analyzed and summarized so as to explore pressing the acupoint the instinct feedback of brain after asthenopia. It is demonstrated that Jingming (BL 1) is a key channel between eyes, brain and the outside world, and it is one of major feedback points of brain after asthenopia. In this paper we try to establish a new research thinking and ascertain it, namely Jingming (BL 1) reflecting the relationship between asthenopia and brainfag. We hope that it can provide some references for further research on cognizing brain through eye.

  3. Pipelining in structural health monitoring wireless sensor network

    NASA Astrophysics Data System (ADS)

    Li, Xu; Dorvash, Siavash; Cheng, Liang; Pakzad, Shamim

    2010-04-01

    Application of wireless sensor network (WSN) for structural health monitoring (SHM), is becoming widespread due to its implementation ease and economic advantage over traditional sensor networks. Beside advantages that have made wireless network preferable, there are some concerns regarding their performance in some applications. In long-span Bridge monitoring the need to transfer data over long distance causes some challenges in design of WSN platforms. Due to the geometry of bridge structures, using multi-hop data transfer between remote nodes and base station is essential. This paper focuses on the performances of pipelining algorithms. We summarize several prevent pipelining approaches, discuss their performances, and propose a new pipelining algorithm, which gives consideration to both boosting of channel usage and the simplicity in deployment.

  4. Tidal Energy Conversion Installation at an Estuarine Bridge Site: Resource Evaluation and Energy Production Estimate

    NASA Astrophysics Data System (ADS)

    Wosnik, M.; Gagnon, I.; Baldwin, K.; Bell, E.

    2015-12-01

    The "Living Bridge" project aims to create a self-diagnosing, self-reporting "smart bridge" powered by a local renewable energy source, tidal energy - transforming Memorial Bridge, a vertical lift bridge over the tidal Piscataqua River connecting Portsmouth, NH and Kittery, ME, into a living laboratory for researchers, engineers, scientists, and the community. The Living Bridge project includes the installation of a tidal turbine at the Memorial Bridge. The energy converted by the turbine will power structural health monitoring, environmental and underwater instrumentation. Utilizing locally available tidal energy can make bridge operation more sustainable, can "harden" transportation infrastructure against prolonged grid outages and can demonstrate a prototype of an "estuarine bridge of the future". A spatio-temporal tidal energy resource assessment was performed using long term bottom-deployed Acoustic Doppler Current Profilers (ADCP) at two locations: near the planned deployment location in 2013-14 for 123 days and mid-channel in 2007 for 35 days. Data were evaluated to determine the amount of available kinetic energy that can be converted into usable electrical energy on the bridge. Changes in available kinetic energy with ebb/flood and spring/neap tidal cycles and electrical energy demand were analyzed. The target deployment site exhibited significantly more energetic ebb tides than flood tides, which can be explained by the local bathymetry of the tidal estuary. A system model is used to calculate the net energy savings using various tidal generator and battery bank configurations. Different resource evaluation methodologies were also analyzed, e.g., using a representative ADCP "bin" vs. a more refined, turbine-geometry-specific methodology, and using static bin height vs. bin height that move w.r.t. the free surface throughout a tidal cycle (representative of a bottom-fixed or floating turbine deployment, respectively). ADCP operating frequencies and bin sizes affect the standard deviation of measurements, and measurement uncertainties are evaluated. The planned installation, consisting of a vertical axis turbine with the generator above water, mounted to a floating platform, and underwater instrumentation will be outlined. Supported by NSF-IIP 1430260

  5. Level II scour analysis for Bridge 25 (ROCHTH00400025) on Town Highway 40, crossing Corporation Brook, Rochester, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Weber, Matthew A.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ROCHTH00400025 on Town Highway 40 crossing Corporation Brook, Rochester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, from Vermont Agency of Transportation files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 4.97-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the upstream left and right overbanks, and the downstream left overbank. On the downstream right overbank, the surface cover is predominately brushland. In the study area, Corporation Brook has an incised, sinuous channel with a slope of approximately 0.04 ft/ft, an average channel top width of 37 ft and an average bank height of 6 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 101 mm (0.332 ft). The geomorphic assessment at the time of the Level I site visit on April 12, 1995 and Level I and II site visit on July 8, 1996, indicated that the reach was stable. The Town Highway 40 crossing of Corporation Brook is a 31-ft-long, one-lane bridge consisting of a 26-foot steel stringer span (Vermont Agency of Transportation, written communication, March 22, 1995). The opening length of the structure parallel to the bridge face is 24 ft. The bridge is supported by vertical, concrete abutments. The channel is skewed approximately 15 degrees to the opening while the opening-skew-to-roadway is 15 degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed in the channel at the downstream bridge face during the Level I assessment. Additionally, it was observed that the left abutment footing was exposed 1.0 ft and the right abutment footing was exposed 2.0 ft. Scour countermeasures at the site included type-1 stone fill (less than 12 inches diameter) along the upstream left and right banks and the downstream left bank. Type-2 stone fill (less than 36 inches diameter) scour protection extended along the downstream right bank and the upstream and downstream ends of the abutments. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.1 to 1.5 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.5 to 7.0 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 5.6 to 6.0 ft. The worst-case right abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  6. Level II scour analysis for Bridge 21 (MONKTH00340021) on Town Highway 34, crossing Little Otter Creek, Monkton, Vermont

    USGS Publications Warehouse

    Boehmler, Erick M.; Medalie, Laura

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure MONKTH00340021 on Town Highway 34 crossing Little Otter Creek, Monkton, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix D of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix C. The site is in the Champlain section of the Saint Lawrence Valley physiographic province in northwestern Vermont. The 34.1-mi2 drainage area is in a predominantly rural and forested basin with pasture in the valleys. In the vicinity of the study site, the surface cover consists of pasture. The most significant tree cover is immediately adjacent to the channel on the right bank downstream. In the study area, Little Otter Creek has a sinuous channel with a slope of approximately 0.008 ft/ft, an average channel top width of 92 feet and an average bank height of 6 feet. The predominant channel bed materials are silt and clay. Sieve analysis indicates that greater than 50% of the sample is silt and clay and thus a median grain size by use of sieve analysis was indeterminate. Therefore, the median grain size was assumed to be medium silt with a size (D50) of 0.0310 mm (0.000102 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 19 and June 20, 1996, indicated that the reach was stable. The Town Highway 34 crossing of Little Otter Creek is a 50-ft-long, one-lane bridge consisting of one 26-foot concrete span and three “boiler tube” smooth metal pipe culverts through the left road approach (Vermont Agency of Transportation, written communication, December 15, 1995). The opening length of the bridge parallel to the bridge face is 25.1 feet. The bridge is supported by vertical, concrete abutments with wingwalls on the right abutment only. The channel is skewed approximately 25 degrees to the opening. The VTAOT records indicate the opening-skew-to-roadway is 20 degrees but measurement from surveyed data suggests the skew is five degrees. The scour protection measures at the site were type-1 stone fill (less than 12 inches diameter) on the upstream and downstream embankments of the left road approach and type-2 stone fill (less than 36 inches diameter) surrounding the entrance of each culvert. Additional details describing conditions at the site are included in the Level II Summary and Appendices C and D. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 10.3 to 12.3 feet. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 8.6 to 22.5 feet. The worst-case abutment scour occurred at the 500-year discharge for the left abutment and at the incipient overtopping discharge for the right abutment. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  7. Level II scour analysis for Bridge 33 (TUNBTH00450033) on Town Highway 45, crossing the First Branch White River, Tunbridge, Vermont

    USGS Publications Warehouse

    Wild, E.C.; Severance, Timothy

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure TUNBTH00450033 on Town Highway 45 crossing the First Branch White River, Tunbridge, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in central Vermont. The 86.4-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge, while woody vegetation sparsely covers the immediate banks. In the study area, the First Branch White River has an incised, sinuous channel with a slope of approximately 0.003 ft/ft, an average channel top width of 68 ft and an average bank height of 7 ft. The channel bed material ranges from sand to gravel with a median grain size (D50) of 27.1 mm (0.089 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 18, 1995, indicated that the reach was laterally unstable due to a cut-bank present on the upstream right bank and a wide channel bar in the upstream reach. The Town Highway 45 crossing of the First Branch White River is a 67-ft-long, one-lane bridge consisting of one 54-foot timber thru-truss span (Vermont Agency of Transportation, written communication, March 23, 1995). The opening length of the structure parallel to the bridge face is 53.5 ft. The bridge is supported on the right by a vertical, concrete abutment with an upstream wingwall, and on the left by a vertical, stone abutment. The channel is skewed approximately 20 degrees to the opening while the computed opening-skew-to-roadway is 10 degrees. A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. Scour countermeasures at the site include type-1 stone fill (less than 12 inches diameter) along the upstream right wingwall, type-2 stone fill (less than 36 inches diameter) along the right abutment, and type-3 stone fill (less than 48 inches diameter) along the upstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 3.0 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 12.8 to 31.0 ft. Right abutment scour ranged from 9.8 to 19.0 ft. The worst-case left and right abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in Tables 1 and 2. A cross-section of the scour computed at the bridge is presented in Figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  8. Dynamics of viscous liquid bridges inside microchannels subject to external oscillatory flow

    NASA Astrophysics Data System (ADS)

    Ahmadlouydarab, Majid; Azaiez, Jalel; Chen, Zhangxin

    2015-02-01

    We report on two-dimensional simulations of liquid bridges' dynamics inside microchannels of uniform wettability and subject to an external oscillatory flow rate. The oscillatory flow results in a zero net flow rate and its effects are compared to those of a stationary system. To handle the three phase contact lines motion, Cahn-Hilliard diffuse-interface formulation was used and the flow equations were solved using the finite element method with adaptively refined unstructured grids. The results indicate that the liquid bridge responds in three different ways depending on the substrate wettability properties and the frequency of the oscillatory flow. In particular below a critical frequency, the liquid bridge will rupture when the channel walls are philic or detach from the surface when they are phobic. However, at high frequencies, the liquid bridge shows a perpetual periodic oscillatory motion for both philic and phobic surfaces. Furthermore, an increase in the frequency of the flow velocity results in stabilization effects and a behavior approaching that of the stationary system where no rupture or detachment can be observed. This stable behavior is the direct result of less deformation of the liquid bridge due to the fast flow direction change and motion of contact lines on the solid substrate. Moreover, it was found that the flow velocity is out of phase with the footprint and throat lengths and that the latter two also show a phase difference. These differences were explained in terms of the motion of the two contact lines on the solid substrates and the deformation of the two fluid-fluid interfaces.

  9. Dynamics of viscous liquid bridges inside microchannels subject to external oscillatory flow.

    PubMed

    Ahmadlouydarab, Majid; Azaiez, Jalel; Chen, Zhangxin

    2015-02-01

    We report on two-dimensional simulations of liquid bridges' dynamics inside microchannels of uniform wettability and subject to an external oscillatory flow rate. The oscillatory flow results in a zero net flow rate and its effects are compared to those of a stationary system. To handle the three phase contact lines motion, Cahn-Hilliard diffuse-interface formulation was used and the flow equations were solved using the finite element method with adaptively refined unstructured grids. The results indicate that the liquid bridge responds in three different ways depending on the substrate wettability properties and the frequency of the oscillatory flow. In particular below a critical frequency, the liquid bridge will rupture when the channel walls are philic or detach from the surface when they are phobic. However, at high frequencies, the liquid bridge shows a perpetual periodic oscillatory motion for both philic and phobic surfaces. Furthermore, an increase in the frequency of the flow velocity results in stabilization effects and a behavior approaching that of the stationary system where no rupture or detachment can be observed. This stable behavior is the direct result of less deformation of the liquid bridge due to the fast flow direction change and motion of contact lines on the solid substrate. Moreover, it was found that the flow velocity is out of phase with the footprint and throat lengths and that the latter two also show a phase difference. These differences were explained in terms of the motion of the two contact lines on the solid substrates and the deformation of the two fluid-fluid interfaces.

  10. Impact of the proposed I-326 crossing on the 500-year flood stages of the Congaree River near Columbia, South Carolina

    USGS Publications Warehouse

    Bennett, C.S.

    1984-01-01

    A two-dimensional finite-element surface water flow modeling system based on the shallow water equations was used to study the hydraulic impact of the proposed Interstate crossing on the 500-year flood. Infrared aerial photography was used to define regions of homogeneous roughness in the flood plain. Finite-element networks approximating flood plain topography were designed using elements of three roughness types. High water marks established during an 8-year flood that occurred in October 1976 were used to calibrate the model. The 500-year flood (630,000 cu ft/sec) was simulated using the dike on the left bank as the left boundary and the right edge of the flood plain as the right boundary. Simulations were performed without and with the proposed highway embankments in place. Detailed information was obtained about backwater effects upstream from the proposed highway embankments, changes in flow distribution resulting from embankments, and velocities in the vicinity of the bridge openings. The results of the study indicate that the four bridge openings in the right flood plain should be adequate to handle the 500-yr flood flow. Forty percent of the flow passes through the main channel bridge, while the remaining 60% of the flow passes through the three overflow bridges. Average velocities in the bridge openings ranged from 3.4 ft/sec to 6.9 ft/sec with a maximum vertically averaged velocity of 9.3 ft/sec occurring at the right edge of one of the overflow bridges. (Author 's abstract)

  11. Level II scour analysis for Bridge 23 (GLOVTH00410023) on Town Highway 41, crossing Sherburne Brook, Glover, Vermont

    USGS Publications Warehouse

    Olson, Scott A.; Boehmler, Erick M.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure GLOVTH00410023 on Town Highway 41 crossing Sherburne Brook, Glover, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in northern Vermont. The 2.57-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is primarily forest with small areas of lawn and a home on the right overbank and a gravel roadway along the upstream left bank. In the study area, Sherburne Brook has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 33 ft and an average bank height of 6 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 57.3 mm (0.188 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 24, 1994, indicated that the reach was stable. The Town Highway 41 crossing of Sherburne Brook is a 24-ft-long, one-lane bridge consisting of one 21-foot steel-beam span with a timber deck (Vermont Agency of Transportation, written communication, August 4, 1994). The opening length of the structure parallel to the bridge face is 20.3 ft. The bridge is supported by vertical, granite block abutments. The channel is skewed approximately 55 degrees to the opening while the measured opening-skew-to-roadway is 30 degrees. One foot of scour below the mean thalweg depth was observed along the right abutment undermining the abutment by 0.5 feet vertically. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.4 to 0.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 4.6 to 7.2 ft. The worst-case abutment scour also occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  12. Level II scour analysis for Bridge 19 (SHEFTH00440019) on Town Highway 44, crossing Trout Brook, Sheffield, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Medalie, Laura

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure SHEFTH00440019 on Town Highway 44 crossing Trout Brook, Sheffield, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the White Mountain section of the New England physiographic province in northeastern Vermont. The 3.0-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is grass on the upstream and downstream right overbanks, while the immediate banks have dense woody vegetation. The surface cover of the upstream and downstream left overbanks is shrub and brushland. In the study area, Trout Brook has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 45 ft and an average bank height of 6 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 116 mm (0.381 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 31, 1995, indicated that the reach was stable. The Town Highway 44 crossing of Trout Brook is a 24-ft-long, one-lane bridge consisting of a 22-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 28, 1994). The opening length of the structure parallel to the bridge face is 19.8 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is zero degrees. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was analyzed since it has the potential of being the worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows resulted in zero ft. Left abutment scour ranged from 4.4 to 5.6 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 3.6 to 4.8 ft. The worst-case right abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particlesize distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  13. Level II scour analysis for Bridge 42 (NEWFTH00350042) on Town Highway 35, crossing Stratton Hill Brook, Newfane, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Ivanoff, Michael A.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure NEWFTH00350042 on Town Highway 35 crossing Stratton Hill Brook, Newfane, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 1.16-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forested. In the study area, Stratton Hill Brook has an incised, striaght channel with a slope of approximately 0.1 ft/ft, an average channel top width of 36 ft and an average bank height of 8 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 121 mm (0.396 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 20, 1996, indicated that the reach was stable. The Town Highway 34 crossing of Stratton Hill Brook is a 34-ft-long, one-lane bridge consisting of a 32-foot steel-beam span (Vermont Agency of Transportation, written communication, April 6, 1995). The opening length of the structure parallel to the bridge face is 30.8 ft. The bridge is supported by vertical, concrete abutments with upstream wingwalls. The channel is skewed approximately 20 degrees to the opening while the computed opening-skew-to-roadway is 15 degrees. During the Level I assessment, it was observed that the right abutment footing was exposed 1.5 feet. The only scour protection measure at the site was type-1 stone fill (less than 12 inches diameter) along the downstream left bank. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was zero ft. Abutment scour ranged from 2.3 to 3.3 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  14. Level II scour analysis for Bridge 17 (LYNDTH00020017) on Town Highway 2, crossing Hawkins Brook, Lyndon, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Medalie, Laura

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure LYNDTH00020017 on Town Highway 2 crossing Hawkins Brook, Lyndon, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.The site is in the Green Mountain section of the New England physiographic province in northeastern Vermont. The 7.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the left and right upstream overbanks. The downstream left and right overbanks are brushland.In the study area, Hawkins Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 78 ft and an average bank height of 7.3 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 46.6 mm (0.153 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 4, 1995, indicated that the reach was laterally unstable with the presence of point bars and side bars.The Town Highway 2 crossing of Hawkins Brook is a 49-ft-long, two-lane bridge consisting of a 46-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 27, 1995). The opening length of the structure parallel to the bridge face is 43 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the computed opening-skew-to-roadway is zero degrees.A scour hole 0.75 ft deeper than the mean thalweg depth was observed along the downstream left abutment during the Level I assessment. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) at the upstream end of the downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled flows ranged from 0.1 to 0.9 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 3.8 to 6.6 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Level II scour analysis for Bridge 32 (HUNTTH00220032) on Town Highway 22, crossing Brush Brook, Huntington, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure HUNTTH00220032 on Town Highway 22 crossing Brush Brook, Huntington, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 5.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest except on the downstream right overbank which is pasture. In the study area, Brush Brook has an incised, straight channel with a slope of approximately 0.05 ft/ft, an average channel top width of 58 ft and an average bank height of 6 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 127 mm (0.416 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 25, 1996, indicated that the reach was stable. The Town Highway 22 crossing of Brush Brook is a 36-ft-long, one-lane bridge consisting of one 34-foot steel-beam span and a timber deck (Vermont Agency of Transportation, written communication, December 12, 1995). The opening length of the structure parallel to the bridge face is 35.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls on the left. The channel is skewed approximately 50 degrees to the opening while the measured opening-skew-to-roadway is 15 degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the left abutment and downstream left wingwall during the Level I assessment. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the upstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.2 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.4 to 10.2 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  16. Level II scour analysis for Bridge 22 (BRADTH00270022) on Town Highway 27, crossing the Waits River, Bradford, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Ivanoff, Michael A.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure BRADTH00270022 on Town Highway 27 crossing the Waits River, Bradford, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, obtained from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in east-central Vermont. The 153-mi2 drainage area is in a predominantly rural and forested basin. However, in the vicinity of the study site, the upstream and downstream left banks are suburban and the upstream and downstream right banks are shrub and brushland. In the study area, the Waits River has an incised, sinuous channel with a slope of approximately 0.0002 ft/ft, an average channel top width of 125 ft and an average bank height of 4 ft. The channel bed material ranges from silt and clay to bedrock with a median grain size (D50) of 0.393 mm (0.00129 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 7, 1995, indicated that the reach was stable. The Town Highway 27 crossing of the Waits River is a 109-ft-long, one-lane bridge consisting of a 104-ft steel-truss span (Vermont Agency of Transportation, written communication, March 16, 1995). The opening length of the structure parallel to the bridge face is 99.2 ft. The bridge is supported by vertical, laid-up stone abutments. The channel is skewed approximately 30 degrees to the opening while the opening-skew-to-roadway is zero degrees. No evidence of scour was observed during the Level I assessment. Scour protection measures at the site included type-2 stone fill (less than 36 inches diameter) along the upstream right and downstream left banks and type-3 stone fill (less than 48 inches diameter) along the left and right abutments. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.5 to 2.0 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 11.8 to 18.8 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results.” Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  17. The contributions of Donald Lee Johnson to understanding the Quaternary geologic and biogeographic history of the California Channel Islands

    USGS Publications Warehouse

    Muhs, Daniel R.

    2013-01-01

    Over a span of 50 years, native Californian Donald Lee Johnson made a number of memorable contributions to our understanding of the California Channel Islands. Among these are (1) recognizing that carbonate dunes, often cemented into eolianite and derived from offshore shelf sediments during lowered sea level, are markers of glacial periods on the Channel Islands; (2) identifying beach rock on the Channel Islands as the northernmost occurrence of this feature on the Pacific Coast of North America; (3) recognizing of the role of human activities in historic landscape modification; (4) identifying both the biogenic and pedogenic origins of caliche “ghost forests” and laminar calcrete forms on the Channel Islands; (5) providing the first soil maps of several of the islands, showing diverse pathways of pedogenesis; (6) pointing out the importance of fire in Quaternary landscape history on the Channel Islands, based on detailed stratigraphic studies; and (7), perhaps his greatest contribution, clarifying the origin of Pleistocene pygmy mammoths on the Channel Islands, due not to imagined ancient land bridges, but rather the superb swimming abilities of proboscideans combined with lowered sea level, favorable paleowinds, and an attractive paleovegetation on the Channel Islands. Don was a classic natural historian in the great tradition of Charles Darwin and George Gaylord Simpson, his role models. Don’s work will remain important and useful for many years and is an inspiration to those researching the California Channel Islands today.

  18. Methodology for Scour Evaluation of US Army Installation Bridges: A Proposed Evaluation for Scour Risk and Channel Instability

    DTIC Science & Technology

    2013-01-01

    rainfall runoff relations ....................................................... 9  Step 2: evaluate hydraulic conditions...earthquakes, landslides , or forest fires might result in a large sediment load. Major changes in the stream might be reflected in aggradation, degradation...removal of material from around piers, abutments, and embankments, caused by an acceleration of flow and by vortices induced by the flow around

  19. 33 CFR 117.799 - Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Parkway bridge, mile 30.7 across State Boat Channel at Captree Island, shall open on signal if at least... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Long Island, New York Inland... Requirements New York § 117.799 Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock...

  20. 33 CFR 117.799 - Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock Canal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Parkway bridge, mile 30.7 across State Boat Channel at Captree Island, shall open on signal if at least... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Long Island, New York Inland... Requirements New York § 117.799 Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock...

  1. 33 CFR 117.799 - Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock Canal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Parkway bridge, mile 30.7 across State Boat Channel at Captree Island, shall open on signal if at least... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Long Island, New York Inland... Requirements New York § 117.799 Long Island, New York Inland Waterway from East Rockaway Inlet to Shinnecock...

  2. Dissociative electron attachment to DNA-diamine thin films: Impact of the DNA close environment on the OH{sup −} and O{sup −} decay channels

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Boulanouar, Omar; Fromm, Michel; Mavon, Christophe

    We measure the desorption of anions stimulated by the impact of 0–20 eV electrons on highly uniform thin films of plasmid DNA-diaminopropane. The results are accurately correlated with film thickness and composition by AFM and XPS measurements, respectively. Resonant structures in the H{sup −}, O{sup −}, and OH{sup −} yield functions are attributed to the decay of transient anions into the dissociative electron attachment (DEA) channel. The diamine induces ammonium-phosphate bridges along the DNA backbone, which suppresses the DEA O{sup −} channel and in counter-part increases considerably the desorption of OH{sup −}. The close environment of the phosphate groups maymore » therefore play an important role in modulating the rate and type of DNA damages induced by low energy electrons.« less

  3. Capillary Condensation in 8 nm Deep Channels.

    PubMed

    Zhong, Junjie; Riordon, Jason; Zandavi, Seyed Hadi; Xu, Yi; Persad, Aaron H; Mostowfi, Farshid; Sinton, David

    2018-02-01

    Condensation on the nanoscale is essential to understand many natural and synthetic systems relevant to water, air, and energy. Despite its importance, the underlying physics of condensation initiation and propagation remain largely unknown at sub-10 nm, mainly due to the challenges of controlling and probing such small systems. Here we study the condensation of n-propane down to 8 nm confinement in a nanofluidic system, distinct from previous studies at ∼100 nm. The condensation initiates significantly earlier in the 8 nm channels, and it initiates from the entrance, in contrast to channels just 10 times larger. The condensate propagation is observed to be governed by two liquid-vapor interfaces with an interplay between film and bridging effects. We model the experimental results using classical theories and find good agreement, demonstrating that this 8 nm nonpolar fluid system can be treated as a continuum from a thermodynamic perspective, despite having only 10-20 molecular layers.

  4. An integrated microfluidic cell for detection, manipulation, and sorting of single micron-sized magnetic beads

    NASA Astrophysics Data System (ADS)

    Jiang, Z.; Llandro, J.; Mitrelias, T.; Bland, J. A. C.

    2006-04-01

    A lab-on-a-chip integrated microfluidic cell has been developed for magnetic biosensing, which is comprised of anisotropic magnetoresistance (AMR) sensors optimized for the detection of single magnetic beads and electrodes to manipulate and sort the beads, integrated into a microfluidic channel. The device is designed to read out the real-time signal from 9 μm diameter magnetic beads moving over AMR sensors patterned into 18×4.5 μm rectangles and 10 μm diameter rings and arranged in Wheatstone bridges. The beads are moved over the sensors along a 75×75 μm wide channel patterned in SU8. Beads of different magnetic moments can be sorted through a magnetostatic sorting gate into different branches of the microfluidic channel using a magnetic field gradient applied by lithographically defined 120 nm thick Cu striplines carrying 0.2 A current.

  5. On Schrödinger's bridge problem

    NASA Astrophysics Data System (ADS)

    Friedland, S.

    2017-11-01

    In the first part of this paper we generalize Georgiou-Pavon's result that a positive square matrix can be scaled uniquely to a column stochastic matrix which maps a given positive probability vector to another given positive probability vector. In the second part we prove that a positive quantum channel can be scaled to another positive quantum channel which maps a given positive definite density matrix to another given positive definite density matrix using Brouwer's fixed point theorem. This result proves the Georgiou-Pavon conjecture for two positive definite density matrices, made in their recent paper. We show that the fixed points are unique for certain pairs of positive definite density matrices. Bibliography: 15 titles.

  6. An Isomorphism between Lyapunov Exponents and Shannon's Channel Capacity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Friedland, Gerald; Metere, Alfredo

    We demonstrate that discrete Lyapunov exponents are isomorphic to numeric overflows of the capacity of an arbitrary noiseless and memoryless channel in a Shannon communication model with feedback. The isomorphism allows the understanding of Lyapunov exponents in terms of Information Theory, rather than the traditional definitions in chaos theory. The result also implies alternative approaches to the calculation of related quantities, such as the Kolmogorov Sinai entropy which has been linked to thermodynamic entropy. This work provides a bridge between fundamental physics and information theory. It suggests, among other things, that machine learning and other information theory methods can bemore » employed at the core of physics simulations.« less

  7. Level II scour analysis for Bridge 52 (CHESTH00100052) on Town Highway 10, crossing the South branch Williams River, Chester, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Ivanoff, Michael A.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure CHESTH00100052 on Town Highway 10 crossing the South Branch Williams River, Chester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 4.05-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream and downstream of the bridge. In the study area, the South Branch Williams River has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 35 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 82.1 mm (0.269 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 21, 1996, indicated that the reach was unstable, as a result of the moderate bank erosion. The Town Highway 10 crossing of the South Branch Williams River is a 32-ft-long, one-lane bridge consisting of a 29-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 31, 1995). The opening length of the structure parallel to the bridge face is 27.6 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 25 degrees to the opening while the opening-skew-to-roadway is 20 degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed at the downstream end of the right abutment during the Level I assessment. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the upstream left and right banks, the upstream end of the upstream right wingwall and the entire base length of the upstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 5.2 to 10.8 ft. The worst-case abutment scour also occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  8. Level II scour analysis for Bridge 47 (PLYMTH00540047) on Town Highway 54, crossing Pinney Hollow Brook, Plymouth, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Weber, Matthew A.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure PLYMTH00540047 on Town Highway 54 crossing Pinney Hollow Brook, Plymouth, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gathered from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in south-central Vermont. The 7.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge while the immediate banks have dense woody vegetation. In the study area, Pinney Hollow Brook has an incised, straight channel with a slope of approximately 0.01 ft/ft, an average channel top width of 57 ft and an average bank height of 7 ft. The channel bed material ranges from sand to cobbles with a median grain size (D50) of 45.7 mm (0.150 ft). The geomorphic assessment at the time of the Level I and Level II site visit on March 30, 1995 and Level II site visit on October 2, 1995, indicated that the reach was stable. The Town Highway 54 crossing of Pinney Hollow Brook is a 30-ft-long, two-lane bridge consisting of a 27-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 22, 1995). The opening length of the structure parallel to the bridge face is 25.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is not skewed to the opening and the opening-skew-to-roadway is zero degrees. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) along the upstream left wingwall, the upstream right wingwall and the downstream end of the downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 2.0 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was less than the 100-year discharge. Left abutment scour ranged from 3.4 to 6.7 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 8.9 to 9.6 ft. The worst-case right abutment scour occurred at the 100-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  9. Level II scour analysis for Bridge 37 (DUXBTH00120037) on Town Highway 12, crossing Ridley Brook, Duxbury, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Ivanhoff, Michael A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure DUXBTH00120037 on Town Highway 12 crossing Ridley Brook, Duxbury, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in north central Vermont. The 10.1-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream and downstream of the bridge. In the study area, Ridley Brook has an incised, straight channel with a slope of approximately 0.04 ft/ft, an average channel top width of 67 ft and an average bank height of 9 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 123 mm (0.404 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 1, 1996, indicated that the reach was stable. The Town Highway 12 crossing of Ridley Brook is a 33-ft-long, two-lane bridge consisting of five 30-ft steel rolled beams (Vermont Agency of Transportation, written communication, October 13, 1995). The opening length of the structure parallel to the bridge face is 30 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 50 degrees to the opening while the measured opening-skew-to-roadway is 20 degrees. A scour hole 2 ft deeper than the mean thalweg depth was observed along the right abutment and downstream right wingwall during the Level I assessment. Scour countermeasures at the site include type-2 stone fill (less than 3 feet diameter) along the upstream and downstream left road embankments, and type-3 stone fill (less than 4 feet diameter) along the upstream right bank and upstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.6 to 1.7 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 5.0 to 8.3 ft, with the worst-case occurring at the incipient-overtopping discharge. Right abutment scour ranged from 13.1 to 16.7 ft, with the worst-case occurring at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  10. Level II scour analysis for Bridge 63 (MTH0TH00120063) on Town Highway 12, crossing Russell Brook, Mount Holly, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Severance, Timothy

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure MTHOTH00120063 on Town Highway 12 crossing Russell Brook, Mount Holly, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in south-central Vermont. The 3.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream and downstream of the bridge. In the study area, Russell Brook has an incised, sinuous channel with a slope of approximately 0.0263 ft/ft, an average channel top width of 29 ft and an average bank height of 3 ft. The channel bed material ranges from cobbles to boulders with a median grain size (D50) of 97.1 mm (0.318 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 4, 1995, indicated that the reach was stable. The Town Highway 12 crossing of Russell Brook is a 29-ft-long, one-lane bridge consisting of a 26-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 21, 1995). The opening length of the structure parallel to the bridge face is 23.5 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 40 degrees to the opening while the computed opening-skew-to-roadway is 35 degrees. During the Level I assessment, it was observed that the upstream left wingwall footing was exposed 0.2 ft, in reference to the mean thalweg depth, and the upstream end of the left abutment was exposed 0.1 ft. The scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the upstream end of the upstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.1 ft. The worst-case contraction scour occurred at the 100-year discharge. Left abutment scour ranged from 4.4 to 5.7 ft. Right abutment scour ranged from 11.3 to 12.2 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  11. Level II scour analysis for Bridge 13 (SHARTH00040013) on Town Highway 4, crossing Broad Brook, Sharon, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Weber, Matthew A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure SHARTH00040013 on Town Highway 4 crossing Broad Brook, Sharon, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.The site is in the New England Upland section of the New England physiographic province in central Vermont. The 16.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is brushland on the downstream left overbank and row crops on the right overbank, while the immediate banks have dense woody vegetation. Upstream of the bridge, the overbanks are forested.In the study area, Broad Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 69 ft and an average bank height of 5 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 112 mm (0.369 ft). The geomorphic assessment at the time of the Level I site visit on April 11, 1995 and Level II site visit on July 23, 1996, indicated that the reach was stable.The Town Highway 4 crossing of Broad Brook is a 34-ft-long, two-lane bridge consisting of one 31-foot concrete tee beam span (Vermont Agency of Transportation, written communication, March 23, 1995). The opening length of the structure parallel to the bridge face is 30.1 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is 15 degrees.A scour hole 2.0 ft deeper than the mean thalweg depth was observed along the upstream end of the right abutment. At the downstream end of the left abutment, a 1.0 foot scour hole was observed . Scour countermeasures at the site include type-2 stone fill (less than 3 feet diameter) at each road embankment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled flows ranged from 0.7 to 1.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 5.6 to 9.4 ft. The worst case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 19.0 to 19.8 ft. The worst-case right abutment scour occurred at the incipient-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  12. Level II scour analysis for Bridge 51 (JERITH00590051) on Town Highway 59, crossing The Creek, Jericho, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure JERITH00590051 on Town Highway 59 crossing The Creek, Jericho, Vermont (figures 1– 8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (Federal Highway Administration, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province and the Champlain section of the St. Lawrence physiographic province in northwestern Vermont. The 10.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture on the left and right overbanks, upstream and downstream of the bridge while the immediate banks have dense woody vegetation. In the study area, The Creek has a sinuous channel with a slope of approximately 0.004 ft/ft, an average channel top width of 45 ft and an average bank height of 6 ft. The channel bed material ranges from silt to cobble with a median grain size (D50) of 58.6 mm (0.192 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 3, 1996, indicated that the reach was stable. The Town Highway 59 crossing of The Creek is a 33-ft-long, two-lane bridge consisting of a 28-foot steel-stringer span (Vermont Agency of Transportation, written communication, December 11, 1995). The opening length of the structure parallel to the bridge face is 26 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the computed opening-skew-toroadway is 5 degrees.A scour hole 3 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. Scour countermeasures at the site included type-1 stone fill (less than 12 inches diameter) at the left and right upstream road embankments. Type-2 stone fill (less than 36 inches diameter) was along the upstream right bank and along the upstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was zero ft. Left abutment scour ranged from 2.4 to 3.2 ft. Right abutment scour ranged from 4.1 to 4.5 ft.The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  13. Level II scour analysis for Bridge 5 (DUMMVT00300005) on State Route 30, crossing Stickney Brook, Dummerston, Vermont

    USGS Publications Warehouse

    Ivanoff, Michael A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure DUMMVT00300005 on State Route 30 crossing Stickney Brook, Dummerston, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 6.31-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest and brush. In the study area, Stickney Brook has an incised, straight channel with a slope of approximately 0.04 ft/ft, an average channel top width of 80 ft and an average bank height of 7 ft. The channel bed material is predominantly cobble with a median grain size (D50) of 80.3 mm (0.264 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 12, 1996, indicated that the reach was aggrading. The State Route 30 crossing of Stickney Brook is a 84-ft-long, two-lane bridge consisting of one 82-foot steel-beam span (Vermont Agency of Transportation, written communication, March 30, 1995). The opening length of the structure parallel to the bridge face is 79.7 ft. The bridge is supported by vertical, concrete abutments with spill-through embankments. The channel is skewed approximately 5 degrees to the opening while the opening-skew-to-roadway is 0 degrees. A scour hole 0.5 ft deeper than the mean thalweg depth was observed along the toe of the right spill-through slope during the Level I assessment. The scour protection measures at the site were type-2 stone fill (less than 36 inches diameter) along the left and right bank under the bridge forming a spill-through slope and type-2 stone fill from approximately 20 ft to 64 ft upstream on the right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.2 ft. The worst-case contraction scour occurred at the 100-year discharge. Left abutment scour ranged from 5.5 to 6.3 ft. Right abutment scour ranged from 2.0 to 3.8 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  14. Level II scour analysis for Bridge 34 (HUNTTH00210034) on Town Highway 21, crossing Brush Brook, Huntington, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Ivanoff, Michael A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure HUNTTH00210034 on Town Highway 21 crossing Brush Brook, Huntington, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 6.23-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest. In the study area, Brush Brook has an incised, straight channel with a slope of approximately 0.03 ft/ft, an average channel top width of 43 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 90.0 mm (0.295 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 26, 1996, indicated that the reach was stable. The Town Highway 21 crossing of Brush Brook is a 28-ft-long, one-lane bridge consisting of one 26-foot steel-beam span with a timber deck (Vermont Agency of Transportation, written communication November 30, 1995). The opening length of the structure parallel to the bridge face is 25.4 ft. The bridge is supported by vertical, concrete abutments with a wingwall on the upstream right. The channel is skewed approximately 5 degrees to the opening and the computed opening-skew-to-roadway is 5 degrees. A tributary enters Brush Brook on the right bank immediately downstream of the bridge. At the confluence, the left bank of Brush Brook is eroded and there is a small void under the downstream end of the left abutment footing which is completely exposed. The right abutment footing is also exposed. The scour countermeasures at the site include type-2 stone fill (less than 36 inches diameter) along the upstream banks and in front of the right abutment and type-3 stone fill (less than 48 inches diameter) along the entire base length of the upstream right wingwall and along the downstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.7 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was less than the 100-year discharge. Abutment scour ranged from 6.9 to 10.9 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Level II scour analysis for Bridge 32 (TUNBTH00600032) on Town Highway 60, crossing First Branch White River, Tunbridge, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure TUNBTH00600032 on Town Highway 60 crossing the First Branch White River, Tunbridge, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in central Vermont. The 92.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge, while woody vegetation sparsely covers the immediate banks. In the study area, the First Branch White River has a sinuous channel with a slope of approximately 0.001 ft/ft, an average channel top width of 82 ft and an average bank height of 7 ft. The channel bed material ranges from sand to gravel with a median grain size (D50) of 24.4 mm (0.08 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 18, 1995, indicated that the reach was laterally unstable, as a result of block failure of moderately eroded banks. The Town Highway 60 crossing of the First Branch White River is a 74-ft-long, one-lane bridge consisting of a 71-foot timber thru-truss span (Vermont Agency of Transportation, written communication, August 24, 1994). The opening length of the structure parallel to the bridge face is 64 ft.The bridge is supported by vertical, laid-up stone abutments with upstream wingwalls. The channel is not skewed to the opening. The computed opening-skew-to-roadway is 5 degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed in the upstream reach during the Level I assessment. Scour countermeasures at the site includes type-1 stone fill (less than 12 inches diameter) along the upstream right bank. Type-2 stone fill (less than 36 inches diameter) is present along the upstream right wingwall, the left abutment and the right abutment. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the maximum free-surface discharge was determined and analyzed as another potential worst-case scour scenarios. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 2.2 to 6.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 20.6 to 30.4 ft. Right abutment scour ranged from 9.7 to 19.5 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  16. Level II scour analysis for Bridge 45 (BRNETH00070045) on Town Highway 7, crossing the Stevens River, Barnet, Vermont

    USGS Publications Warehouse

    Ivanoff, Michael A.; Hammond, Robert E.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure BRNETH00070045 on Town Highway 7 crossing the Stevens River, Barnet, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in east-central Vermont. The 41.5-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream and pasture downstream of the bridge while the immediate banks have dense woody vegetation. In the study area, the Stevens River has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 100 ft and an average bank height of 17 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 105 mm (0.344 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 22, 1995, indicated that the reach was stable. The Town Highway 7 crossing of the Stevens River is a 37-ft-long, two-lane bridge consisting of one 34-foot concrete slab span (Vermont Agency of Transportation, written communication, March 16, 1995). The opening length of the structure parallel to the bridge face is 33 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is 20 degrees. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) along the entire left and right abutments, upstream and downstream wingwalls, and upstream and downstream banks. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.8 to 5.4 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was greater than the 100-year discharge. Left abutment scour ranged from 21.8 to 28.6 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 14.6 to 17.4 ft. The worst-case right abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  17. Recent applications of acoustic Doppler current profilers

    USGS Publications Warehouse

    Oberg, K.A.; Mueller, David S.

    1994-01-01

    A Broadband acoustic Doppler current profiler (BB-ADCP) is a new instrument being used by the U.S. Geological Survey (USGS) to measure stream discharge and velocities, and bathymetry. During the 1993 Mississippi River flood, more than 160 high-flow BB-ADCP measurements were made by the USGS at eight locations between Quincy and Cairo, Ill., from July 19 to August 20, 1993. A maximum discharge of 31,400 m3/s was measured at St. Louis, Mo., on August 2, 1993. A BB-ADCP also has been used to measure leakage through three control structures near Chicago, Ill. These measurements are unusual in that the average velocity for the measured section was as low as 0.03 m/s. BB-ADCP's are also used in support of studies of scour at bridges. During the recent Mississippi River flood, BB-ADCP's were used to measure water velocities and bathymetry upstream from, next to, and downstream from bridge piers at several bridges over the Mississippi River. Bathymetry data were collected by merging location data from Global Positioning System (GPS) receivers, laser tracking systems, and depths measured by the BB-ADCP. These techniques for collecting bathymetry data were used for documenting the channel formation downstream from the Miller City levee break and scour near two bridges on the Mississippi River.

  18. Status in the development of self-powered wireless sensor node for structural health monitoring and prognosis

    NASA Astrophysics Data System (ADS)

    Godinez-Azcuaga, Valery F.; Farmer, Justin; Ziehl, Paul H.; Giurgiutiu, Victor; Nanni, Antonio; Inman, Daniel J.

    2012-04-01

    This paper discusses the development status of a self-powered wireless sensor node for steel and concrete bridges monitoring and prognosis. By the end of the third year in this four-year cross-disciplinary project, the 4-channel acoustic emission wireless node, developed by Mistras Group Inc, has already been deployed in concrete structures by the University of Miami. Also, extensive testing is underway with the node powered by structural vibration and wind energy harvesting modules developed by Virginia Tech. The development of diagnosis tools and models for bridge prognosis, which will be discussed in the paper, continues and the diagnosis tools are expected to be programmed in the node's AVR during the 4th year of the project. The impact of this development extends beyond the area of bridge health monitoring into several fields, such as offshore oil platforms, composite components on military ships and race boats, combat deployable bridges and wind turbine blades. Some of these applications will also be discussed. This project was awarded to a joint venture formed by Mistras Group Inc, Virginia Tech, University of South Carolina and University of Miami by the National Institute of Standards and Technology through its Technology Innovation Program Grant #70NANB9H007.

  19. Recent advances in the development of a self-powered wireless sensor network for structural health prognosis

    NASA Astrophysics Data System (ADS)

    Godinez-Azcuaga, Valery F.; Inman, Daniel J.; Ziehl, Paul H.; Giurgiutiu, Victor; Nanni, Antonio

    2011-04-01

    This paper presents the most recent advances in the development of a self powered wireless sensor network for steel and concrete bridges monitoring and prognosis. This five-year cross-disciplinary project includes development and deployment of a 4-channel acoustic emission wireless node powered by structural vibration and wind energy harvesting modules. In order to accomplish this ambitious goal, the project includes a series of tasks that encompassed a variety of developments such as ultra low power AE systems, energy harvester hardware and especial sensors for passive and active acoustic wave detection. Key studies on acoustic emission produced by corrosion on reinforced concrete and by crack propagation on steel components to develop diagnosis tools and models for bridge prognosis are also a part of the project activities. It is important to mention that the impact of this project extends beyond the area of bridge health monitoring. Several wireless prototype nodes have been already requested for applications on offshore oil platforms, composite ships, combat deployable bridges and wind turbines. This project was awarded to a joint venture formed by Mistras Group Inc, Virginia Tech, University of South Carolina and University of Miami and is sponsored through the NIST-TIP Grant #70NANB9H007.

  20. Comparative proteomic analysis of male and female venoms from the Cuban scorpion Rhopalurus junceus.

    PubMed

    Rodríguez-Ravelo, Rodolfo; Batista, Cesar V F; Coronas, Fredy I V; Zamudio, Fernando Z; Hernández-Orihuela, Lorena; Espinosa-López, Georgina; Ruiz-Urquiola, Ariel; Possani, Lourival D

    2015-12-01

    A complete mass spectrometry analysis of venom components from male and female scorpions of the species Rhophalurus junceus of Cuba is reported. In the order of 200 individual molecular masses were identified in both venoms, from which 63 are identical in male and females genders. It means that a significant difference of venom components exists between individuals of different sexes, but the most abundant components are present in both sexes. The relative abundance of identical components is different among the genders. Three well defined groups of different peptides were separated and identified. The first group corresponds to peptides with molecular masses of 1000-2000 Da; the second to peptides with 3500-4500 Da molecular weight, and the third with 6500-8000 Da molecular weights. A total of 86 peptides rich in disulfide bridges were found in the venoms, 27 with three disulfide bridges and 59 with four disulfide bridges. LC-MS/MS analysis allowed the identification and amino acid sequence determination of 31 novel peptides in male venom. Two new putative K(+)-channel peptides were sequences by Edman degradation. They contain 37 amino acid residues, packed by three disulfide bridges and were assigned the systematic numbers: α-KTx 1.18 and α-KTx 2.15. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. QPatch: the missing link between HTS and ion channel drug discovery.

    PubMed

    Mathes, Chris; Friis, Søren; Finley, Michael; Liu, Yi

    2009-01-01

    The conventional patch clamp has long been considered the best approach for studying ion channel function and pharmacology. However, its low throughput has been a major hurdle to overcome for ion channel drug discovery. The recent emergence of higher throughput, automated patch clamp technology begins to break this bottleneck by providing medicinal chemists with high-quality, information-rich data in a more timely fashion. As such, these technologies have the potential to bridge a critical missing link between high-throughput primary screening and meaningful ion channel drug discovery programs. One of these technologies, the QPatch automated patch clamp system developed by Sophion Bioscience, records whole-cell ion channel currents from 16 or 48 individual cells in a parallel fashion. Here, we review the general applicability of the QPatch to studying a wide variety of ion channel types (voltage-/ligand-gated cationic/anionic channels) in various expression systems. The success rate of gigaseals, formation of the whole-cell configuration and usable cells ranged from 40-80%, depending on a number of factors including the cell line used, ion channel expressed, assay development or optimization time and expression level in these studies. We present detailed analyses of the QPatch features and results in case studies in which secondary screening assays were successfully developed for a voltage-gated calcium channel and a ligand-gated TRP channel. The increase in throughput compared to conventional patch clamp with the same cells was approximately 10-fold. We conclude that the QPatch, combining high data quality and speed with user friendliness and suitability for a wide array of ion channels, resides on the cutting edge of automated patch clamp technology and plays a pivotal role in expediting ion channel drug discovery.

  2. Book lung development in juveniles and adults of the cobweb spider, Parasteatoda tepidariorum C. L. Koch, 1841 (Araneomorphae, Theridiidae).

    PubMed

    Farley, Roger D

    2018-03-01

    Light and transmission electron microscopy were used to study the development of new book lung lamellae in juvenile and adult spiders (Parasteatoda tepidariorum). As hypothesized earlier in a study of embryos, mesenchyme cells dispersed throughout the opisthosoma (EMT) are a likely source of precursor epithelial cells (MET) for the new lamellae. The precursor cells in juveniles and adults continue many of the complex activities observed in embryos, e.g., migration, alignment, lumen formation, thinning, elongation, and secretion of the cuticle of air channel walls and trabeculae. The apicobasal polarity of precursor cells for new channels is apparently induced by the polarity pattern of precursor cells of channels produced earlier. Thus, new air and hemolymph channels extend and continue the alternating pattern of older channels. At sites more distant from the spiracle and atrium, new channels are usually produced by the mode II process (intracellular alignment and merging of vesicles). These air channels have bridging trabeculae and are quite stable in size throughout their length. At sites closer to the spiracle and atrium, new channels may be produced by mode I (coalescence of merocrine vesicle secretion). This raises the hypothesis that structural and functional differences in mode I and II channels and differing oxygen and fluid conditions with distance from the spiracle and atrium determine the mode of formation of new channels. Observations herein support an earlier hypothesis that there is some intercellular apical/apical and basal/basal affinity among the opposed surfaces of aligned precursor cells. This results in the alternating pattern of air channels at the apical and hemolymph channels at the basal cell surfaces. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  3. Large wood recruitment and transport during large floods: A review

    NASA Astrophysics Data System (ADS)

    Comiti, F.; Lucía, A.; Rickenmann, D.

    2016-09-01

    Large wood (LW) elements transported during large floods are long known to have the capacity to induce dangerous obstructions along the channel network, mostly at bridges and at hydraulic structures such as weirs. However, our current knowledge of wood transport dynamics during high-magnitude flood events is still very scarce, mostly because these are (locally) rare and thus unlikely to be directly monitored. Therefore, post-event surveys are invaluable ways to get insights (although indirectly) on LW recruitment processes, transport distance, and factors inducing LW deposition - all aspects that are crucial for the proper management of river basins related to flood hazard mitigation. This paper presents a review of the (quite limited) literature available on LW transport during large floods, drawing extensively on the authors' own experience in mountain and piedmont rivers, published and unpublished. The overall picture emerging from these studies points to a high, catchment-specific variability in all the different processes affecting LW dynamics during floods. Specifically, in the LW recruitment phase, the relative floodplain (bank erosion) vs. hillslope (landslide and debris flows) contribution in mountain rivers varies substantially, as it relates to the extent of channel widening (which depends on many variables itself) but also to the hillslope-channel connectivity of LW mobilized on the slopes. As to the LW transport phase within the channel network, it appears to be widely characterized by supply-limited conditions; whereby LW transport rates (and thus volumes) are ultimately constrained by the amount of LW that is made available to the flow. Indeed, LW deposition during floods was mostly (in terms of volume) observed at artificial structures (bridges) in all the documented events. This implies that the estimation of LW recruitment and the assessment of clogging probabilities for each structure (for a flood event of given magnitude) are the most important aspects for the prediction of LW transport magnitude at any cross section along the river network. Finally, the review discusses the optimal strategies to manage LW-related hazard, which should consider riparian vegetation and in-channel dead wood as key components of river ecosystems and thus should interfere with LW (as well as with sediment) transport dynamics only for limited spatial and temporal scales.

  4. Water level, specific conductance, and water temperature data, San Francisco Bay, California, for Water Year 2000

    USGS Publications Warehouse

    Buchanan, P.A.

    2002-01-01

    Time series of water-level, specific-conductance, and watertemperature data were collected at seven sites in San Francisco Bay during water year 2000 (October 1, 1999 through September 30, 2000). Water-level data were recorded only at Point San Pablo. Specific-conductance and water-temperature data were recorded at 15-minute intervals at the following locations (Figure 1): • Carquinez Strait at Carquinez Bridge • Napa River at Mare Island Causeway near Vallejo • San Pablo Bay at Petaluma River Channel Marker 9 • San Pablo Strait at Point San Pablo • Central San Francisco Bay at Presidio Military Reservation • Central San Francisco Bay at Pier 24 • South San Francisco Bay at San Mateo Bridge near Foster City.

  5. Level II scour analysis for Bridge 7 (WALDTH00020007) on Town Highway 2, crossing Coles Brook, Walden, Vermont

    USGS Publications Warehouse

    Striker, Lora K.; Medalie, Laura

    1997-01-01

    ft, an average channel top width of 37 ft and an average bank height of 4 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 32.9 mm (0.108 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 9, 1995, indicated that the reach was laterally unstable due to cut-banks, point bars, and loose unconsolidated bed material. The Town Highway 2 crossing of Coles Brook is a 74-ft-long, two-lane bridge consisting of one 71-foot steel-beam span (Vermont Agency of Transportation, written communication, April 5, 1995). The opening length of the structure parallel to the bridge face is 69.3 ft. The bridge is supported by spill-through abutments. The channel is skewed approximately 35 degrees to the opening while the measured opening-skew-to-roadway is 15 degrees. A scour hole 1.5 ft deeper than the mean thalweg depth was observed from 60 ft. to 100 ft. downstream during the Level I assessment. Scour protection measures at the site include: type-1 stone fill (less than 12 inches diameter) along the right bank upstream, at the downstream end of the downstream left wingwall and downstream right wingwall; and type-2 stone fill (less than 36 inches diameter) along the left bank upstream, at the upstream end of the upstream right wingwall, and along the entire base of the left and right abutments. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.8 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge. Abutment scour ranged from 5.7 to 12.9 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  6. Molecular Dynamics Simulation Reveals Specific Interaction Sites between Scorpion Toxins and Kv1.2 Channel: Implications for Design of Highly Selective Drugs

    PubMed Central

    Yuan, Shouli; Gao, Bin

    2017-01-01

    The Kv1.2 channel plays an important role in the maintenance of resting membrane potential and the regulation of the cellular excitability of neurons, whose silencing or mutations can elicit neuropathic pain or neurological diseases (e.g., epilepsy and ataxia). Scorpion venom contains a variety of peptide toxins targeting the pore region of this channel. Despite a large amount of structural and functional data currently available, their detailed interaction modes are poorly understood. In this work, we choose four Kv1.2-targeted scorpion toxins (Margatoxin, Agitoxin-2, OsK-1, and Mesomartoxin) to construct their complexes with Kv1.2 based on the experimental structure of ChTx-Kv1.2. Molecular dynamics simulation of these complexes lead to the identification of hydrophobic patches, hydrogen-bonds, and salt bridges as three essential forces mediating the interactions between this channel and the toxins, in which four Kv1.2-specific interacting amino acids (D353, Q358, V381, and T383) are identified for the first time. This discovery might help design highly selective Kv1.2-channel inhibitors by altering amino acids of these toxins binding to the four channel residues. Finally, our results provide new evidence in favor of an induced fit model between scorpion toxins and K+ channel interactions. PMID:29104247

  7. Level II scour analysis for Bridge 44 (CHESVT00110044) on State Route 11, crossing Andover Brook, Chester, Vermont

    USGS Publications Warehouse

    Ivanoff, Michael A.; Hammond, Robert E.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure CHESVT00110044 on State Route 11 crossing Andover Brook, Chester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 12.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture with dense woody vegetation on the immediate banks except the downstream left bank of the bridge which is forested. In the study area, Andover Brook has an incised, meandering channel with a slope of approximately 0.02 ft/ft, an average channel top width of 74 ft and an average bank height of 8 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 83.6 mm (0.274 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 11, 1996, indicated that the reach was stable. The State Route 11 crossing of Andover Brook is a 58-ft-long, two-lane bridge consisting of one 56-foot concrete T-beam span (Vermont Agency of Transportation, written communication, March 29, 1995). The opening length of the structure parallel to the bridge face is 52.9 ft.The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 35 degrees to the opening while the opening-skew-to-roadway is 45 degrees. A scour hole 1.8 ft deeper than the mean thalweg depth was observed along the upstream left wingwall and left abutment during the Level I assessment. The scour protection measures at the site included type-4 stone fill (less than 60 inches diameter) along the upstream left bank between the wingwall and a concrete wall. There was type-2 stone fill (less than 36 inches diameter) along the entire base of the upstream left wingwall, and the downstream end of the downstream right wingwall. There was type-1 stone fill (less than 12 inches diameter) at the downstream end of the downstream left wingwall. There was also a concrete wall along the upstream left bank from 18 to 50 ft upstream of the bridge. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 1.2 ft. The worst-case contraction scour occurred at the incipient-overtopping discharge. The incipientovertopping discharge is 520 cfs less than the 100-year discharge. Left abutment scour ranged from 16.4 to 20.9 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 8.4 to 9.4 ft. The worst-case right abutment scour occurred at both the 100-year and 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  8. Level II scour analysis for Bridge 30 (NEWHTH00050030) on Town Highway 5, crossing the New Haven River, New Haven, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure NEWHTH00050030 on Town Highway 5 crossing the New Haven River, New Haven, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (Federal Highway Administration, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D.The site is in the Champlain section of the St. Lawrence Valley physiographic province in west-central Vermont. The 115-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture on the right bank upstream and downstream of the bridge while the immediate banks have dense woody vegetation. The upstream left bank is also pasture. The downstream left bank is forested.In the study area, the New Haven River has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 127 ft and an average bank height of 5 ft. The channel bed material ranges from silt to cobble with a median grain size (D50) of 20.4 mm (0.067 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 19, 1996, indicated that the reach was laterally unstable. The stream bends through the bridge and impacts the left bank where there is a cut bank and scour hole.The Town Highway 5 crossing of the New Haven River is a 181-ft-long, two-lane bridge consisting of four 45-ft concrete tee-beam spans (Vermont Agency of Transportation, written communication, December 15, 1995). The opening length of the structure parallel to the bridge face is 175.9 ft. The bridge is supported by vertical, concrete abutments with stone fill spill-through embankments and three concrete piers. The channel is skewed approximately 15 degrees to the opening while the computed opening-skew-to-roadway is 10 degrees.A scour hole 4.5 ft deeper than the mean thalweg depth was observed along the downstream left bank during the Level I assessment. Also observed was a scour hole 1.5 ft deeper than the mean thalweg depth at the upstream end of the middle pier. The only scour protection measure at the site was type-3 stone fill (less than 48 inches diameter) in front of the left and right abutments creating spill through slopes. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled flows ranged from 0.7 to 2.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.8 to 8.4 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 11.2 to 14.0 ft. The worst-case right abutment scour occurred at the 500-year discharge. Pier scour ranged from 12.9 to 19.3 ft. The worst-case pier scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  9. Distribution of Escherichia coli and Enterococci in water, sediments, and bank soils along North Shore Channel between Bridge Street and Wilson Avenue, Metropolitan Water Reclamation District of Greater Chicago

    USGS Publications Warehouse

    Byappanahalli, Muruleedhara; Whitman, Richard L.; Shively, Dawn; Przybyla-Kelly, Katarzyna; Lukasik, Ashley M.

    2010-01-01

    The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) wished to know the distribution and potential sources of fecal indicator bacteria, E. coli and enterococci, in water, sediments, and upland soils along an upstream and downstream portion of the North Shore Channel (NSC) that is the receiving stream for the District’s North Side Water Reclamation Plant (NSWRP) outfall. Biweekly water and sediment samples were collected between August and October 2008 and included the following locations upstream of the outfall: Bridge Street (UPS-1), Oakton Street (UPS-2), the NSWRP outfall (OF), and downstream: Foster Avenue (DNS-1), and Wilson Avenue (DNS-2). E. coli and enterococci were consistently found in water and sediments at all sampling locations, with bacterial densities in water increasing below the NSWRP outfall; bacterial densities in sediment were more variable. On a relative measurement basis (i.e., 100 ml=100 g), both E. coli and enterococci densities were significantly higher in sediments than water. E. coli and enterococci were consistently recovered from bank soil along wooded, grassy, erosional, and depositional areas at two recreational parks, as well as other riparian areas along the river. Thus, soils along the river basin are likely sources of these bacteria to the NSC channel, introduced through runoff or other physical processes. Tributaries, such as the North Branch of the Chicago River (NBCR) that flow into NSC near Albany Ave, may provide a constant source of E. coli and enterococci to the NSC. Additionally, storm sewer outfalls may increase E. coli loadings to NSC during wet weather conditions. Our findings suggest that the abundance of nonpoint sources contributing to the overall fecal indicator bacteria (FIB) load in the NSC channel may complicate bacteria source determination and remediation efforts to protect the stream water quality.

  10. PROFILE: Hungry Water: Effects of Dams and Gravel Mining on River Channels

    PubMed

    Kondolf

    1997-07-01

    / Rivers transport sediment from eroding uplands to depositional areas near sea level. If the continuity of sediment transport is interrupted by dams or removal of sediment from the channel by gravel mining, the flow may become sediment-starved (hungry water) and prone to erode the channel bed and banks, producing channel incision (downcutting), coarsening of bed material, and loss of spawning gravels for salmon and trout (as smaller gravels are transported without replacement from upstream). Gravel is artificially added to the River Rhine to prevent further incision and to many other rivers in attempts to restore spawning habitat. It is possible to pass incoming sediment through some small reservoirs, thereby maintaining the continuity of sediment transport through the system. Damming and mining have reduced sediment delivery from rivers to many coastal areas, leading to accelerated beach erosion. Sand and gravel are mined for construction aggregate from river channel and floodplains. In-channel mining commonly causes incision, which may propagate up- and downstream of the mine, undermining bridges, inducing channel instability, and lowering alluvial water tables. Floodplain gravel pits have the potential to become wildlife habitat upon reclamation, but may be captured by the active channel and thereby become instream pits. Management of sand and gravel in rivers must be done on a regional basis, restoring the continuity of sediment transport where possible and encouraging alternatives to river-derived aggregate sources.KEY WORDS: Dams; Aquatic habitat; Sediment transport; Erosion; Sedimentation; Gravel mining

  11. Experimental and Analytical Seismic Studies of a Four-Span Bridge System with Innovative Materials

    NASA Astrophysics Data System (ADS)

    Cruz Noguez, Carlos Alonso

    As part of a multi-university project utilizing the NSF Network for Earthquake Engineering Simulation (NEES), a quarter-scale model of a four-span bridge incorporating plastic hinges with different advanced materials was tested to failure on the three shake table system at the University of Nevada, Reno (UNR). The bridge was the second test model in a series of three 4-span bridges, with the first model being a conventional reinforced-concrete (RC) structure. The purpose of incorporating advanced materials was to improve the seismic performance of the bridge with respect to two damage indicators: (1) column damage and (2) permanent deformations. The goals of the study presented in this document were to (1) evaluate the seismic performance of a 4-span bridge system incorporating SMA/ECC and built-in rubber pad plastic hinges as well as post-tensioned piers, (2) quantify the relative merit of these advanced materials and details compared to each other and to conventional reinforced concrete plastic hinges, (3) determine the influence of abutment-superstructure interaction on the response, (4) examine the ability of available elaborate analytical modeling techniques to model the performance of advanced materials and details, and (5) conduct an extensive parametric study of different variations of the bridge model to study several important issues in bridge earthquake engineering. The bridge model included six columns, each pair of which utilized a different advanced detail at bottom plastic hinges: shape memory alloys (SMA), special engineered cementitious composites (ECC), elastomeric pads embedded into columns, and post-tensioning tendons. The design of the columns, location of the bents, and selection of the loading protocol were based on pre-test analyses conducted using computer program OpenSees. The bridge model was subjected to two-horizontal components of simulated earthquake records of the 1994 Northridge earthquake. Over 340 channels of data were collected. The test results showed the effectiveness of the advanced materials in reducing damage and permanent displacements. The damage was minimal in plastic hinges with SMA/ECC and those with built-in elastomeric pads. Conventional RC plastic hinges were severely damaged due to spalling of concrete and rupture of the longitudinal and transverse reinforcement. Extensive post-test analytical studies were conducted and it was determined that a computational model of the bridge that included bridge-abutment interaction using OpenSees was able to provide satisfactory estimations of key structural parameters such as superstructure displacements and base shears. The analytical model was also used to conduct parametric studies on single-column and bridge-system response under near-fault ground motions. The effects of vertical excitations and transverse shear-keys at the bridge abutments on the superstructure displacement and column drifts were also explored.

  12. Reversible electrochemical modification of the surface of a semiconductor by an atomic-force microscope probe

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kozhukhov, A. S., E-mail: antonkozhukhov@yandex.ru; Sheglov, D. V.; Latyshev, A. V.

    A technique for reversible surface modification with an atomic-force-microscope (AFM) probe is suggested. In this method, no significant mechanical or topographic changes occur upon a local variation in the surface potential of a sample under the AFM probe. The method allows a controlled relative change in the ohmic resistance of a channel in a Hall bridge within the range 20–25%.

  13. The role of beaver in shaping steelhead trout (Oncorhynchus mykiss) habitat complexity and thermal refugia in a central Oregon stream

    NASA Astrophysics Data System (ADS)

    Consolati, F.; Wheaton, J. M.; Neilson, B. T.; Bouwes, N.; Pollock, M. M.

    2012-12-01

    The incised and degraded habitat of Bridge Creek, tributary to the John Day River in central Oregon, is thought to be limiting the local population of ESA-listed steelhead trout (Oncorhynchus mykiss). Restoration efforts for this watershed are aimed to improve their habitat through reconnecting the channel with portions of its former floodplain (now terraces) to increase stream habitat complexity and the extent of riparian vegetation. This is being done via the installation of over a hundred beaver dam support (BDS) structures that are designed to either mimic beaver dams or support existing beaver dams. The overall objective of this study is to determine if the BDS structures have had an effect on stream channel habitat complexity and thermal refugia in selected sections of Bridge Creek. Analysis of stream temperature data in restoration treatment and control areas will show the effects of beaver dams on stream temperature. Analysis of aerial imagery and high resolution topographic data will exhibit how the number and types of geomorphic units have changed after the construction of beaver dams. Combined, the results of this research are aimed to increase our understanding of how beaver dams impact fish habitat and stream temperature.

  14. A Quasi-Elastic Neutron Scattering Study of the Dynamics of Electrically Constrained Water.

    PubMed

    Fuchs, Elmar C; Bitschnau, Brigitte; Wexler, Adam D; Woisetschläger, Jakob; Freund, Friedemann T

    2015-12-31

    We have measured the quasi-elastic neutron scattering (QENS) of an electrohydrodynamic liquid bridge formed between two beakers of pure water when a high voltage is applied, a setup allowing to investigate water under high-voltage without high currents. From this experiment two proton populations were distinguished: one consisting of protons strongly bound to oxygen atoms (immobile population, elastic component) and a second one of quasi-free protons (mobile population, inelastic component) both detected by QENS. The diffusion coefficient of the quasi-free protons was found to be D = (26 ± 10) × 10(-5) cm(2) s(-1) with a jump length lav ∼ 3 Å and an average residence time of τ0 = 0.55 ± 0.08 ps. The associated proton mobility in the proton channel of the bridge is ∼9.34 × 10(-7) m(2) V(-1) s(-1), twice as fast as diffusion-based proton mobility in bulk water. It also matches the so-called electrohydrodynamic or "apparent" charge mobility, an experimental quantity which so far has lacked molecular interpretation. These results further corroborate the proton channel model for liquid water under high voltage and give new insights into the molecular mechanisms behind electrohydrodynamic charge transport phenomena and delocalization of protons in liquid water.

  15. Influences of high-flow events on a stream channel altered by construction of a highway bridge: A case study

    USGS Publications Warehouse

    Hedrick, Lara B.; Welsh, Stuart A.; Anderson, James T.

    2009-01-01

    Impacts of highway construction on streams in the central Appalachians are a growing concern as new roads are created to promote tourism and economic development in the area. Alterations to the streambed of a first-order stream, Sauerkraut Run, Hardy County, WV, during construction of a highway overpass included placement and removal of a temporary culvert, straightening and regrading of a section of stream channel, and armourment of a bank with a reinforced gravel berm. We surveyed longitudinal profiles and cross sections in a reference reach and the altered reach of Sauerkraut Run from 2003 through 2007 to measure physical changes in the streambed. During the four-year period, three high-flow events changed the streambed downstream of construction including channel widening and aggradation and then degradation of the streambed. Upstream of construction, at a reinforced gravel berm, bank erosion was documented. The reference section remained relatively unchanged. Knowledge gained by documenting channel changes in response to natural and anthropogenic variables can be useful for managers and engineers involved in highway construction projects.

  16. Cloning and characterization of BmK86, a novel K{sup +}-channel blocker from scorpion venom

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mao, Xin; Cao, Zhijian; Yin, Shijin

    2007-09-07

    Scorpion venom represents a tremendous hitherto unexplored resource for understanding ion channels. BmK86 is a novel K{sup +}-channel toxin gene isolated from a cDNA library of Mesobuthus martensii Karsch, which encodes a signal peptide of 22 amino acid residues and a mature toxin of 35 residues with three disulfide bridges. The genomic sequence of BmK86 consists of two exons disrupted by an intron of 72 bp. Comparison with the other scorpion toxins BmK86 shows low sequence similarity. The GST-BmK86 fusion protein was successfully expressed in Escherichia coli. The fusion protein was cleaved by enterokinase and the recombinant BmK86 was purifiedmore » by HPLC. Using whole-cell patch-clamp recording, the recombinant BmK86 was found to inhibit the potassium current of mKv1.3 channel expressed in COS7 cells. These results indicated that BmK86 belongs to a representative member of a novel subfamily of {alpha}-KTxs. The systematic number assigned to BmK86 is {alpha}-KTx26.1.« less

  17. Assessing the continuity of the upland sediment cascade, fluvial geomorphic response of an upland river to an extreme flood event: Storm Desmond, Cumbria, UK.

    NASA Astrophysics Data System (ADS)

    Joyce, Hannah; Hardy, Richard; Warburton, Jeff

    2017-04-01

    Hillslope erosion and accelerated lake sedimentation are often viewed as the source and main storage elements in the upland sediment cascade. However, the continuity of sediment transfer through intervening valley systems has rarely been evaluated during extreme events. Storm Desmond (4th - 6th December, 2015) produced record-breaking rainfall maximums in the UK: 341.4 mm rainfall was recorded in a 24 hour period at Honister Pass, Western Lake District, and 405 mm of rainfall was recorded in a 38 hour period at Thirlmere, central Lake District. The storm was the largest in a 150 year local rainfall series, and exceeded previous new records set in the 2005 and 2009 floods. During this exceptional event, rivers over topped flood defences, and caused damage to over 257 bridges, flooded over 5000 homes and businesses, and caused substantial geomorphic change along upland rivers. This research quantifies the geomorphic and sedimentary response to Storm Desmond along a regulated gravel-bed river: St John's Beck. St John's Beck (length 7.8 km) is a channelised low gradient river (0.005) downstream of Thirlmere Reservoir, which joins the River Greta, and flows through Keswick, where major flooding has occurred, before discharging into Bassenthwaite Lake. St John's Beck has a history of chronic sediment aggradation, erosion and reports of historic flooding date back to 1750. During Storm Desmond, riverbanks were eroded, coarse sediment was deposited across valuable farmland and access routes were destroyed, including a bridge and footpaths, disrupting local business. A sediment budget framework has been used to quantify geomorphic change and sedimentary characteristics of the event along St John's Beck. The volume and sediment size distribution of flood deposits, channel bars, tributary deposits, floodplain scour, riverbank erosion and in-channel bars were measured directly in the field and converted to mass using local estimates of coarse and fine sediment bulk densities. During the event 5000 tonnes of sediment was deposited on floodplains surrounding St John's Beck; 65% of this sediment was deposited in the first 3 km of the reach downstream of Thirlmere Reservoir where the channel is unconfined and channel slope and capacity rapidly decrease. Flood sediment deposits were composed of a single layer of sediment of a similar grain size distribution (mean D90 116 mm), with fines generally sparse. The main source of sediment deposited during the event originated from the channel bed and banks; 1500 tonnes of sediment was stored within channel bars. Approximately 2000 tonnes of sediment was eroded from the riverbanks during the event; with local lateral riverbank recession exceeding 12 m. An estimated 500 tonnes of sediment was scoured from the floodplains along the first 3 km of the reach downstream of Thirlmere Reservoir, with local floodplain scour around a bridge estimated at 300 tonnes. Overall, this sediment budget study demonstrates the importance of valley systems as a major source and sink of sediment along the upland sediment cascade during an extreme flood event.

  18. Algorithms for highway-speed acoustic impact-echo evaluation of concrete bridge decks

    NASA Astrophysics Data System (ADS)

    Mazzeo, Brian A.; Guthrie, W. Spencer

    2018-04-01

    A new acoustic impact-echo testing device has been developed for detecting and mapping delaminations in concrete bridge decks at highway speeds. The apparatus produces nearly continuous acoustic excitation of concrete bridge decks through rolling mats of chains that are placed around six wheels mounted to a hinged trailer. The wheels approximately span the width of a traffic lane, and the ability to remotely lower and raise the apparatus using a winch system allows continuous data collection without stationary traffic control or exposure of personnel to traffic. Microphones near the wheels are used to record the acoustic response of the bridge deck during testing. In conjunction with the development of this new apparatus, advances in the algorithms required for data analysis were needed. This paper describes the general framework of the algorithms developed for converting differential global positioning system data and multi-channel audio data into maps that can be used in support of engineering decisions about bridge deck maintenance, rehabilitation, and replacement (MR&R). Acquisition of position and audio data is coordinated on a laptop computer through a custom graphical user interface. All of the streams of data are synchronized with the universal computer time so that audio data can be associated with interpolated position information through data post-processing. The audio segments are individually processed according to particular detection algorithms that can adapt to variations in microphone sensitivity or particular chain excitations. Features that are greater than a predetermined threshold, which is held constant throughout the analysis, are then subjected to further analysis and included in a map that shows the results of the testing. Maps of data collected on a bridge deck using the new acoustic impact-echo testing device at different speeds ranging from approximately 10 km/h to 55 km/h indicate that the collected data are reasonably repeatable. Use of the new acoustic impact-echo testing device is expected to enable more informed decisions about MR&R of concrete bridge decks.

  19. VALVE

    DOEpatents

    Arkelyan, A.M.; Rickard, C.L.

    1962-04-17

    A gate valve for controlling the flow of fluid in separate concentric ducts or channels by means of a single valve is described. In one position, the valve sealing discs engage opposed sets of concentric ducts leading to the concentric pipes defining the flow channels to block flow therethrough. In another position, the discs are withdrawn from engagement with the opposed ducts and at the same time a bridging section is interposed therebetween to define concentric paths coextensive with and connecting the opposed ducts to facilitate flow therebetween. A wedge block arrangement is employed with each sealing disc to enable it to engage the ducts. The wedge block arrangement also facilitates unobstructcd withdrawal of the discs out of the intervening space between the sets of ducts. (AEC)

  20. Quantum key distribution with untrusted detectors

    NASA Astrophysics Data System (ADS)

    González, P.; Rebón, L.; Ferreira da Silva, T.; Figueroa, M.; Saavedra, C.; Curty, M.; Lima, G.; Xavier, G. B.; Nogueira, W. A. T.

    2015-08-01

    Side-channel attacks currently constitute the main challenge for quantum key distribution (QKD) to bridge theory with practice. So far two main approaches have been introduced to address this problem, (full) device-independent QKD and measurement-device-independent QKD. Here we present a third solution that might exceed the performance and practicality of the previous two in circumventing detector side-channel attacks, which arguably is the most hazardous part of QKD implementations. Our proposal has, however, one main requirement: the legitimate users of the system need to ensure that their labs do not leak any unwanted information to the outside. The security in the low-loss regime is guaranteed, while in the high-loss regime we already prove its robustness against some eavesdropping strategies.

  1. Public channel cryptography: chaos synchronization and Hilbert's tenth problem.

    PubMed

    Kanter, Ido; Kopelowitz, Evi; Kinzel, Wolfgang

    2008-08-22

    The synchronization process of two mutually delayed coupled deterministic chaotic maps is demonstrated both analytically and numerically. The synchronization is preserved when the mutually transmitted signals are concealed by two commutative private filters, a convolution of the truncated time-delayed output signals or some powers of the delayed output signals. The task of a passive attacker is mapped onto Hilbert's tenth problem, solving a set of nonlinear Diophantine equations, which was proven to be in the class of NP-complete problems [problems that are both NP (verifiable in nondeterministic polynomial time) and NP-hard (any NP problem can be translated into this problem)]. This bridge between nonlinear dynamics and NP-complete problems opens a horizon for new types of secure public-channel protocols.

  2. Entanglement routers via a wireless quantum network based on arbitrary two qubit systems

    NASA Astrophysics Data System (ADS)

    Metwally, N.

    2014-12-01

    A wireless quantum network is generated between multi-hops, where each hop consists of two entangled nodes. These nodes share a finite number of entangled two-qubit systems randomly. Different types of wireless quantum bridges (WQBS) are generated between the non-connected nodes. The efficiency of these WQBS to be used as quantum channels between its terminals to perform quantum teleportation is investigated. We suggest a theoretical wireless quantum communication protocol to teleport unknown quantum signals from one node to another, where the more powerful WQBS are used as quantum channels. It is shown that, by increasing the efficiency of the sources that emit the initial partial entangled states, one can increase the efficiency of the wireless quantum communication protocol.

  3. Examination of Single- and Multi-Channel GPR Bridge Deck Condition Assessment Methods with Comparison to Complementary NDE Results

    NASA Astrophysics Data System (ADS)

    Romero, Francisco A.; Manacorda, Guido; Simi, Alessandro; Gucunski, Nenad; Parvardeh, Hooman

    2013-04-01

    A sixteen-channel GPR system which houses both longitudinally- and transversely-polarized, 2.0 GHz antenna elements within a single housing was compared with a single-channel GPR system that was separately using both 1.5GHz and 2.6GHz antennas oriented in the transverse polarization, for the purpose of determining effectiveness of bridge deck condition assessment. The multi-channel system has obvious benefits which include closely-spaced GPR antennas (channels) that provide better lateral resolution, as well as combined data sets from co-linear antennas oriented in both the transverse and longitudinal polarizations, which has benefits for imaging within the deck's internal structure. However, the primary objective was to determine whether the multi-channel system would perform in a similar manner to proven single-channel GPR technology during an attenuation-based GPR condition assessment on an older, partially deteriorated deck in northwestern New Jersey that is annually exposed to freeze-thaw conditions as well as de-icing salts. These assessments were made by focusing on identifying the strongest reflections from the upper mat of transversely-oriented rebars within the deck and comparing reflection strength, or conversely, attenuation of the GPR signal, from each of the 'picked' GPR rebar responses. Coordinates for each of the GPR picks, along with amplitude or attenuation measurements, were gridded and contour-plotted for the purpose of identifying areas identified as either relatively deteriorated or sound. Initially, results were compared for data with no applied correction that takes into account GPR signal attenuation with increasing depth within the concrete deck. Final GPR maps were produced incorporating a depth-correction technique similar to what is described by Barnes, et. al., Romero, et. al, and Gucunski, et. al., a process which has been clearly demonstrated to better correlate GPR results with not only ground truth (cores, sounding) but also with other NDE technologies. Not only did all the single- and multi-channel system comparisons generate nearly identical deterioration maps when GPR results were compared and examined, but mapped results obtained from other NDE methods on the same deck were used to identify zones where corrosive environment (electrical resistivity - ER) elastic modulus (ultrasonic surface wave - USW), and identified delaminations (impact-echo - IE) had commonality with the GPR results. A summary of the equipment used, as well as general data collection and analysis procedures is provided for the GPR condition assessments. Brief descriptions of background and references to how the complementary NDT technologies are deployed, and how data are interpreted, are also discussed. Comparative maps for all technologies are used for illustrative purposes.

  4. Level II scour analysis for Bridge 26 (WSTOTH00070026) on Town Highway 7, crossing Greendale Brook, Weston, Vermont

    USGS Publications Warehouse

    Striker, Lora K.; Hammond, Robert A.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure WSTOTH00070026 on Town Highway 7 crossing Greendale Brook, Weston, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in south central Vermont. The 3.13-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest. In the study area, the Greendale Brook has a sinuous, non-incised, non-alluvial channel with a slope of approximately 0.015 ft/ft, an average channel top width of 38 ft and an average bank height of 3 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 64.8 mm (0.213 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 19, 1996, indicated that the reach was laterally unstable. The channel has moved to the right, however, scour countermeasures are in place along the upstream right bank. The Town Highway 7 crossing of the Greendale Brook is a 52-ft-long, two-lane bridge consisting of one 50-foot steel-beam span with a concrete deck (Vermont Agency of Transportation, written communication, April 07, 1995). The opening length of the structure parallel to the bridge face is 48.6 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 50 degrees to the opening while the opening-skew-to-roadway is 30 degrees. A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the upstream right wingwall and right abutment during the Level I assessment. Scour protection measures at the site include: type-2 stone fill (less than 36 inches diameter) at the upstream end of the upstream left wingwall, along the left bank upstream, at the downstream end of the downstream left wing wall, and along the entire length of the downstream right wing wall; type 4 (less than 60 inches) and type-3 stone fill (less than 48 inches) along the right bank upstream. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was 0.0 ft. Abutment scour ranged from 3.9 to 9.9 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). The Hire equation (abutment scour) is often used when the horizontal length blocked by flow divided by the depth of flow is greater than 25 (Richardson and others, 1995 p. 49). Although the Hire equation could be applied to the left abutment more conservative scour estimates were given by the Froehlich equation on the left abutment. Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  5. Level II scour analysis for Bridge 41 (ANDOVT00110041) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Hammond, Robert E.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ANDOVT00110041 on State Route 11 crossing the Middle Branch Williams River, Andover, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in southeastern Vermont. The 12.1-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is grass on the upstream right overbank while the immediate banks have dense woody vegetation. The upstream left overbank and downstream right overbank are brushland. The downstream left overbank is forested. In the study area, the Middle Branch Williams River has an incised, sinuous channel with a slope of approximately 0.018 ft/ft, an average channel top width of 71 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 85.0 mm (0.279 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 10, 1996, indicated that the reach was laterally unstable due to a cut-bank present on the upstream right bank and a wide channel bar with vegetation in the upstream reach. The State Route 11 crossing of the Middle Branch Williams River is a 46-ft-long, two-lane bridge consisting of a concrete 44-foot tee-beam span (Vermont Agency of Transportation, written communication, March 29, 1995). The opening length of the structure parallel to the bridge face is 42 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 35 degrees to the opening while the opening-skew-toroadway is zero degrees. A scour hole 0.8 ft deeper than the mean thalweg depth was observed along the downstream end of the left abutment and downstream left wingwall during the Level I assessment. Type- 2 stone fill (less than 36 inches diameter) protects the upstream end of the upstream left wingwall, the downstream ends of the downstream left and right wingwalls and the downstream right road embankment. Type-3 stone fill protects the upstream end of the upstream right wingwall and the upstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 2.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 11.1 to 18.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  6. Level II scour analysis for Bridge 34 (WWINTH00370034) on Town Highway 37, crossing Mill Brook, West Windsor, Vermont

    USGS Publications Warehouse

    Boehmler, Erick M.; Wild, Emily C.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure WWINTH00370034 on Town Highway 37 crossing Mill Brook, West Windsor, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in east-central Vermont. The 16.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture except for the upstream left bank where there is mostly shrubs and brush. In the study area, Mill Brook has a sinuous channel with a slope of approximately 0.003 ft/ ft, an average channel top width of 52 ft and an average bank height of 5 ft. The channel bed material ranges from sand to cobbles with a median grain size (D50) of 43.4 mm (0.142 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 5, 1996, indicated that the reach was laterally unstable. Point bars were observed upstream and downstream of this site. Furthermore, slip failure of the bank material was noted downstream at a cut-bank on the left side of the channel across from a point bar. The Town Highway 37 crossing of Mill Brook is a 37-ft-long, one-lane covered bridge consisting of one 32-foot wood thru-truss span (Vermont Agency of Transportation, written communication, March 23, 1995). The opening length of the structure parallel to the bridge face is 29.6 ft. The bridge is supported by vertical, laid-up stone abutment walls with concrete facing and laid-up stone wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is zero degrees. A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. Scour protection measures at the site included type-3 (less than 48 inches diameter) and type-4 (less than 60 inches diameter) stone fill. Type-3 stone fill was observed along the upstream right bank and along the right abutments. Type-4 stone fill was observed at the upstream end of the upstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. There was no contraction scour predicted for any of the modeled flows. Abutment scour at the left abutment ranged from 5.7 to 7.3 ft, while that at the right abutment ranged from 11.6 to 17.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results.” Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  7. Using HEC-RAS to Enhance Interpretive Capabilities of Geomorphic Assessments

    NASA Astrophysics Data System (ADS)

    Keefer, L. L.

    2005-12-01

    The purpose of a geomorphic assessment is to characterize and evaluate a fluvial system for determining the past watershed and channel conditions, current geomorphic character and potential future channel adjustments. The geomorphic assessment approach utilized by the Illinois State Water Survey assesses channel response to disturbance at multiple temporal and spatial scales to help identify the underlying factors and events which led to the existing channel morphology. This is accomplished through two phases of investigation that involve a historical and physical analysis of the watershed, disturbance history, and field work at increasing levels of detail. To infer future channel adjustments, the geomorphic assessment protocol combines two methods of analyses that are dependent on the quantity and detail of the available data. The first method is the compilation of multiple lines of evidence using qualitative information related to the dominant fluvial environment, channel gradient, stream power thresholds, and channel evolution models. The second method is the use of hydraulic models which provide additional interpretative skills to evaluate potential channel adjustments. The structured data collection framework of the geomorphic assessment approach is used for the development of a HEC-RAS model. The model results are then used as another tool to determine the influence of bridges and control structures on channel stability, stream power profiles to identify potential channel bed degradation zones, and provide data for physically-based bank stability models. This poster will demonstrate the advantages of using a hydraulic model, such as HEC-RAS, to expand the interpretive capabilities of geomorphic assessments. The results from applying this approach will be demonstrated for the Big Creek watershed of the Cache River Basin in southern Illinois.

  8. O' Connell bridge inspection by means of Ground Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Santos Assuncao, Sonia, ,, Dr

    2016-04-01

    Ground Penetrating Radar (GPR) is a well-known technique successfully applied in different areas. In structural inspection the methodology may expose information about structural arrangement and pathologies. GPR emits high frequency electromagnetic impulses allowing to detect changes on the electromagnetic properties: electrical conductivity, dielectric constant and magnetic permeability. The central frequency of the each antenna is characterized by a specific resolution and penetration depth. Therefore, different scales of structures can be analysed. High frequency antennas output high resolution images/signals about the shallowest elements such as rebar and the thickness of the first layer. On the other hand, intermediate or lower frequency antennas locate deeper structures, such as the thickness of the arch. The compilation of distinct frequencies gives a better understanding and a more accurate detection of elements in the inner structure. O'Connell Bridge (1877) is one of 24 bridges along River Liffey and one the most famous historical structures in Dublin. It is composed by sandstones and granite and covered by asphalt which represents a suitable structure to evaluate by means of GPR. The lack of inner structural information, especially the thickness of the layer, presence of reinforcement or other metallic elements of support required, at least, a dual frequency analysis of the bridge. In this case, it was applied the (200 MHz and 600 MHz) Multi-Channel Stream EM combined with 1.6 GHz GSSI high frequency antenna. The inspection of bridges by means of GPR may provide not exclusively interesting structural data but historical information and the state of conservation.

  9. Formation of nanoscale water bridges

    NASA Astrophysics Data System (ADS)

    Riedo, Elisa; Szoszkiewicz, Robert; Li, Tai-De; Gao, Jianping; Landman, Uzi

    2006-03-01

    The water bridges provide stability to sand castles, act as transport channels for dip-pen nanolitography and increase adhesion and friction in micro- and nano- devices such as MEMS. The kinetics of capillary condensation and growth at the nanoscale is studied here using friction force microscopy and molecular dynamics calculations. At 40% relative humidity we find that the meniscus nucleation times increase from 0.7 ms up to 4.2 ms when the temperature decreases from 332 K to 299 K. The nucleation times grow exponentially with the inverse temperature 1/T obeying an Arrhenius law. We obtain a nucleation energy barrier of 7.8*10̂-20˜J and an attempt frequency ranging between 4-250˜GHz, in excellent agreement with theoretical predictions. These results provide direct experimental evidence that capillary condensation is a thermally activated phenomenon.

  10. Selective carbon dioxide sorption by a new breathing three-dimensional Zn-MOF with Lewis basic nitrogen-rich channels.

    PubMed

    Kim, Hyun-Chul; Huh, Seong; Lee, Do Nam; Kim, Youngmee

    2018-04-03

    Lewis basic heteroatoms orderly located inside the well-defined channels of metal-organic frameworks (MOFs) are potentially ideal active sites for selective gas sorption and catalysis. To develop functional MOFs with Lewis basic sites inside channels, a new C2h-symmetric dicarboxylate-based bridging ligand, 3,3'-(pyrazine-2,5-diyl)dibenzoic acid (3,3'-PDBA), was prepared by a Suzuki coupling reaction. Subsequently, two new Zn-MOFs containing the C2h-symmetric 3,3'-PDBA bridging ligand and two different bis(pyridyl)-based pillars, 1,2-bis(4-pyridyl)ethane (bpa) or 1,2-bis(4-pyridyl)ethylene (bpe), were prepared through a thermal reaction in N,N-dimethylformamide (DMF). The resulting two Zn-MOFs of the general formula of three-dimensional (3D) [Zn2(μ4-3,3'-PDBA)2(μ2-bpa)]3·(DMF)5(H2O)13 (1) or 3D-like 2D [Zn2(μ4-3,3'-PDBA)2(μ2-bpe)]·(H2O) (2) displayed primitive cubic pcu net and 2D sql net, respectively. Both Zn-MOFs 1 and 2 contain uncoordinated Lewis basic pyrazinyl nitrogen atoms in the frameworks. The solvent-free 1 with flexible bpa linkers only showed a potential porosity of 15.9% by PLATON analysis. Zn-MOF 1 with openly accessible Lewis basic sites exhibited selective sorption of CO2 over N2, H2, and CH4 at low temperature. The adsorption and desorption isotherms for CO2 sorption at 196 K showed phenomenal hysteretic behaviour indicative of a breathing process through an adsorbate-discriminatory gate-opening process toward CO2 at a low gas pressure.

  11. Water exit pathways and proton pumping mechanism in B-type cytochrome c oxidase from molecular dynamics simulations.

    PubMed

    Yang, Longhua; Skjevik, Åge A; Han Du, Wen-Ge; Noodleman, Louis; Walker, Ross C; Götz, Andreas W

    2016-09-01

    Cytochrome c oxidase (CcO) is a vital enzyme that catalyzes the reduction of molecular oxygen to water and pumps protons across mitochondrial and bacterial membranes. While proton uptake channels as well as water exit channels have been identified for A-type CcOs, the means by which water and protons exit B-type CcOs remain unclear. In this work, we investigate potential mechanisms for proton transport above the dinuclear center (DNC) in ba3-type CcO of Thermus thermophilus. Using long-time scale, all-atom molecular dynamics (MD) simulations for several relevant protonation states, we identify a potential mechanism for proton transport that involves propionate A of the active site heme a3 and residues Asp372, His376 and Glu126(II), with residue His376 acting as the proton-loading site. The proposed proton transport process involves a rotation of residue His376 and is in line with experimental findings. We also demonstrate how the strength of the salt bridge between residues Arg225 and Asp287 depends on the protonation state and that this salt bridge is unlikely to act as a simple electrostatic gate that prevents proton backflow. We identify two water exit pathways that connect the water pool above the DNC to the outer P-side of the membrane, which can potentially also act as proton exit transport pathways. Importantly, these water exit pathways can be blocked by narrowing the entrance channel between residues Gln151(II) and Arg449/Arg450 or by obstructing the entrance through a conformational change of residue Tyr136, respectively, both of which seem to be affected by protonation of residue His376. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. 59. MISSISSIPPI, NOXUBEE CO. MACON Ms. 14 E to McLeod, ...

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

    59. MISSISSIPPI, NOXUBEE CO. MACON Ms. 14 E to McLeod, 6.5 Mi S 4.5 miles S on McLeod-Shuqualak road. Lower chord of turn span, SW side looking W. Shows two different ways of joining the channel beams of chord: lattice, and bolts in 'dumbell' -shaped sleeves or spacers. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  13. Use of GDNF-Releasing Nanofiber Nerve Guide Conduits for the Repair of Conus medullaris/Cauda Equina Injury in the Non-Human Primate

    DTIC Science & Technology

    2011-10-01

    Cauda equina, non-human primate, ventral root. neural repair, electromyography , magnetic resonance imaging 16. SECURITY CLASSIFICATION OF: 17...of a guidance channel without GDNF release and a peripheral nerve graft to bridge the tissue gap. A comprehensive set of electrodiagnostic, imaging ... Electromyography (EMG) recordings of the external anal sphincter are obtained pre-operatively as baseline records. The external anal sphincter muscle

  14. Photographic copy of historic photograph, by Corps of Engineers, U.S. ...

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

    Photographic copy of historic photograph, by Corps of Engineers, U.S. Army, May 23, 1940 (original in possession of Corps of Engineers, U.S. Army, Pittsburgh District, Engineering Division files) Unit 3, view of channel excavation downstream at Fourth Avenue Bridge - Johnstown Local Flood Protection Project, Beginning on Conemaugh River approx 3.8 miles downstream from confluence of Little Conemaugh & Stony Creek Rivers at Johnstown, Johnstown, Cambria County, PA

  15. Photographic copy of historic photograph, by Corps of Engineers, U.S. ...

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

    Photographic copy of historic photograph, by Corps of Engineers, U.S. Army, April 24, 1942 (original in possession of Corps of Engineers, U.S. Army, Pittsburgh District, Engineering Division files) Unit 5, view of channel excavation upstream at Franklin Street Bridge - Johnstown Local Flood Protection Project, Beginning on Conemaugh River approx 3.8 miles downstream from confluence of Little Conemaugh & Stony Creek Rivers at Johnstown, Johnstown, Cambria County, PA

  16. A π-π 3D network of tetranuclear μ2/μ3-carbonato Dy(III) bis-pyrazolylpyridine clusters showing single molecule magnetism features.

    PubMed

    Gass, Ian A; Moubaraki, Boujemaa; Langley, Stuart K; Batten, Stuart R; Murray, Keith S

    2012-02-18

    2,6-Di(pyrazole-3-yl)pyridine, 3-bpp, forms a porous (4(9)·6(6)) π-π mediated 3D network of trigonal pyramidal [Dy(III)(4)] carbonato-bridged complexes, with hexagonal channels comprising 54% of the unit cell volume, the material displaying slow magnetisation reversal. This journal is © The Royal Society of Chemistry 2012

  17. PIXE Analysis of Metal Hull Bolts From HMB DeBraak

    NASA Astrophysics Data System (ADS)

    Correll, Francis D.; Cole, Lord K.; Slater, Charles J.; Vanhoy, Jeffrey R.; Fithian, Charles H.

    2009-03-01

    HMB DeBraak was a 16-gun British brig-sloop that sank in a squall on May 25, 1798 off Cape Henlopen, Delaware. Silt covered the wooden hull shortly after it sank, preserving it until DeBraak was raised in 1986. The items recovered from the ship include metal bolts that held the hull together. We used PIXE to measure the compositions of 45 of the bolts and found that they are nearly pure copper (98.3% on average), with most also containing small amounts of iron (0.87%), nickel (0.039%), arsenic (0.43%), silver (0.089%), lead (0.18%), and bismuth (0.12%). A few contain a little indium, tin, or antimony, but none contain zinc above the quantization level. The compositions are similar to those reported for 18th-century English copper, but different from several copper alloys also used to make hull bolts. We conclude that, when DeBraak was last fitted out in 1795-1797, the Royal Navy was still using bolts similar to William Forbes's mechanically hardened pure copper bolts. Forbes's process represents the successful innovation and application of new technology in Royal Navy ships during the wars of the late 18th century.

  18. High performance interconnection between high data rate networks

    NASA Technical Reports Server (NTRS)

    Foudriat, E. C.; Maly, K.; Overstreet, C. M.; Zhang, L.; Sun, W.

    1992-01-01

    The bridge/gateway system needed to interconnect a wide range of computer networks to support a wide range of user quality-of-service requirements is discussed. The bridge/gateway must handle a wide range of message types including synchronous and asynchronous traffic, large, bursty messages, short, self-contained messages, time critical messages, etc. It is shown that messages can be classified into three basic classes, synchronous and large and small asynchronous messages. The first two require call setup so that packet identification, buffer handling, etc. can be supported in the bridge/gateway. Identification enables resequences in packet size. The third class is for messages which do not require call setup. Resequencing hardware based to handle two types of resequencing problems is presented. The first is for a virtual parallel circuit which can scramble channel bytes. The second system is effective in handling both synchronous and asynchronous traffic between networks with highly differing packet sizes and data rates. The two other major needs for the bridge/gateway are congestion and error control. A dynamic, lossless congestion control scheme which can easily support effective error correction is presented. Results indicate that the congestion control scheme provides close to optimal capacity under congested conditions. Under conditions where error may develop due to intervening networks which are not lossless, intermediate error recovery and correction takes 1/3 less time than equivalent end-to-end error correction under similar conditions.

  19. Recombinant Expression, Functional Characterization of Two Scorpion Venom Toxins with Three Disulfide Bridges from the Chinese Scorpion Buthus martensii Karsch.

    PubMed

    Lin, Shengguo; Wang, Xuelin; Hu, Xueyao; Zhao, Yongshan; Zhao, Mingyi; Zhang, Jinghai; Cui, Yong

    2017-01-01

    Scorpion venom contains a large variety of biologically active peptides. However, most of these peptides have not been identified and characterized. Peptides with three disulfide bridges, existing in the scorpion venom, have not been studied in detail and have been poorly characterized until now. Here, we report the recombinant expression and functional characterization of two kinds of venom peptides (BmKBTx and BmNaL-3SS2) with three disulfide bridges. This study adopted an effective Escherichia coli system. The genes for BmKBTx and BmNaL-3SS2 were obtained by polymerase chain reaction and cloned to the pSYPU-1b vector. After expression and purification, the two recombinant proteins were subjected to an analgesic activity assay in mice and whole-cell patchclamp recording of hNav1.7-CHO cell lines. Functional tests showed that BmKBTx and BmNaL- 3SS2 have analgesic activity in mice and can interact with the hNav1.7 subtype of the voltage-gated sodium channel (VGSC). Scorpion venom is rich in bioactive proteins, but most of their functions are unknown to us. This study has increased our knowledge of these novel disulfide-bridged peptides (DBPs) and their biological activities. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  20. Arthroscopically Assisted Reconstruction of Acute Acromioclavicular Joint Dislocations: Anatomic AC Ligament Reconstruction With Protective Internal Bracing—The “AC-RecoBridge” Technique

    PubMed Central

    Izadpanah, Kaywan; Jaeger, Martin; Ogon, Peter; Südkamp, Norbert P.; Maier, Dirk

    2015-01-01

    An arthroscopically assisted technique for the treatment of acute acromioclavicular joint dislocations is presented. This pathology-based procedure aims to achieve anatomic healing of both the acromioclavicular ligament complex (ACLC) and the coracoclavicular ligaments. First, the acromioclavicular joint is reduced anatomically under macroscopic and radiologic control and temporarily transfixed with a K-wire. A single-channel technique using 2 suture tapes provides secure coracoclavicular stabilization. The key step of the procedure consists of the anatomic repair of the ACLC (“AC-Reco”). Basically, we have observed 4 patterns of injury: clavicular-sided, acromial-sided, oblique, and midportion tears. Direct and/or transosseous ACLC repair is performed accordingly. Then, an X-configured acromioclavicular suture tape cerclage (“AC-Bridge”) is applied under arthroscopic assistance to limit horizontal clavicular translation to a physiological extent. The AC-Bridge follows the principle of internal bracing and protects healing of the ACLC repair. The AC-Bridge is tightened on top of the repair, creating an additional suture-bridge effect and promoting anatomic ACLC healing. We refer to this combined technique of anatomic ACLC repair and protective internal bracing as the “AC-RecoBridge.” A detailed stepwise description of the surgical technique, including indications, technical pearls and pitfalls, and potential complications, is given. PMID:26052493

  1. Use of surface-geophysical methods to assess riverbed scour at bridge piers

    USGS Publications Warehouse

    Gorin, S.R.; Haeni, F.P.

    1989-01-01

    A ground-penetrating-radar system, and three seismic systems--color fathometer, tuned transducer, and black-and-white fathometer--were used to evaluate river-bed scour at the Charter Oak, Founder 's and Bulkeley Bridges in Hartford, Connecticut. Cross-sections of the channel and some lateral sections were run at each bridge in June and July 1987, and significant scour at piers supporting each of these bridges was recorded. Each of the four geophysical systems proved to have advantages and limitations. The ground penetrating radar system used single and dual 80 megahertz antennae floating in the water to transmit and receive the signal. The method was successful in water less than 25 ft deep, and in resistive earth materials. The geometry of existing scour holes and the extent of post-scour sedimentation were clearly defined. The color fathometer, operating at a signal frequency of 20 kilohertz, delineated existing scour-hole geometry, detected infilling of scour holes, and provided qualitative information about the physical properties of sediments. The tuned transducer, operating at a signal frequency of 14 kilohertz, defined scour-hole geometry and the extent of post-scour sediment deposition. Both of these systems were effective in water greater than 5 ft deep. At a signal frequency of 200 kilohertz, the black-and-white fathometer could not penetrate post-scour deposits, but it was useful in defining existing scour-holed geometry in water of any depth. (USGS)

  2. Detecting subsurface features and distresses of roadways and bridge decks with ground penetrating radar at traffic speed

    NASA Astrophysics Data System (ADS)

    Liu, Hao; Birken, Ralf; Wang, Ming L.

    2017-04-01

    This paper presents the detections of the subsurface features and distresses in roadways and bridge decks from ground penetrating radar (GPR) data collected at traffic speed. This GPR system is operated at 2 GHz with a penetration depth of 60 cm in common road materials. The system can collect 1000 traces a second, has a large dynamic range and compact packaging. Using a four channel GPR array, dense spatial coverage can be achieved in both longitudinal and transversal directions. The GPR data contains significant information about subsurface features and distresses resulting from dielectric difference, such as distinguishing new and old asphalt, identification of the asphalt-reinforced concrete (RC) interface, and detection of rebar in bridge decks. For roadways, the new and old asphalt layers are distinguished from the dielectric and thickness discontinuities. The results are complemented by surface images of the roads taken by a video camera. For bridge decks, the asphalt-RC interface is automatically detected by a cross correlation and Hilbert transform algorithms, and the layer properties (e.g., dielectric constant and thickness) can be identified. Moreover, the rebar hyperbolas can be visualized from the GPR B-scan images. In addition, the reflection amplitude from steel rebar can be extracted. It is possible to estimate the rebar corrosion level in concrete from the distribution of the rebar reflection amplitudes.

  3. Hydraulic modeling of stream channels and structures in Harbor and Crow Hollow Brooks, Meriden, Connecticut

    USGS Publications Warehouse

    Weiss, Lawrence A.; Sears, Michael P.; Cervione, Michael A.

    1994-01-01

    Effects of urbanization have increased the frequency and size of floods along certain reaches of Harbor Brook and Crow Hollow Brook in Meriden, Conn. A floodprofile-modeling study was conducted to model the effects of selected channel and structural modifications on flood elevations and inundated areas. The study covered the reach of Harbor Brook downstream from Interstate 691 and the reach of Crow Hollow Brook downstream from Johnson Avenue. Proposed modifications, which include changes to bank heights, channel geometry, structural geometry, and streambed armoring on Harbor Brook and changes to bank heights on Crow Hollow Brook, significantly lower flood elevations. Results of the modeling indicate a significant reduction of flood elevations for the 10-year, 25-year, 35-year, 50-year, and 100-year flood frequencies using proposed modifications to (1 ) bank heights between Harbor Brook Towers and Interstate 691 on Harbor Brook, and between Centennial Avenue and Johnson Avenue on Crow Hollow Brook; (2) channel geometry between Coe Avenue and Interstate 69 1 on Harbor Brook; (3) bridge and culvert opening geometry between Harbor Brook Towers and Interstate 691 on Harbor Brook; and (4) channel streambed armoring between Harbor Brook Towers and Interstate 691 on Harbor Brook. The proposed modifications were developed without consideration of cost-benefit ratios.

  4. Connections matter: channeled hydrogels to improve vascularization.

    PubMed

    Muehleder, Severin; Ovsianikov, Aleksandr; Zipperle, Johannes; Redl, Heinz; Holnthoner, Wolfgang

    2014-01-01

    The use of cell-laden hydrogels to engineer soft tissue has been emerging within the past years. Despite, several newly developed and sophisticated techniques to encapsulate different cell types the importance of vascularization of the engineered constructs is often underestimated. As a result, cell death within a construct leads to impaired function and inclusion of the implant. Here, we discuss the fabrication of hollow channels within hydrogels as a promising strategy to facilitate vascularization. Furthermore, we present an overview on the feasible use of removable spacers, 3D laser-, and planar processing strategies to create channels within hydrogels. The implementation of these structures promotes control over cell distribution and increases oxygen transport and nutrient supply in vitro. However, many studies lack the use of endothelial cells in their approaches leaving out an important factor to enhance vessel ingrowth and anastomosis formation upon implantation. In addition, the adequate endothelial cell type needs to be considered to make these approaches bridge the gap to in vivo applications.

  5. µ-Conotoxins Modulating Sodium Currents in Pain Perception and Transmission: A Therapeutic Potential

    PubMed Central

    Tosti, Elisabetta; Boni, Raffaele

    2017-01-01

    The Conus genus includes around 500 species of marine mollusks with a peculiar production of venomous peptides known as conotoxins (CTX). Each species is able to produce up to 200 different biological active peptides. Common structure of CTX is the low number of amino acids stabilized by disulfide bridges and post-translational modifications that give rise to different isoforms. µ and µO-CTX are two isoforms that specifically target voltage-gated sodium channels. These, by inducing the entrance of sodium ions in the cell, modulate the neuronal excitability by depolarizing plasma membrane and propagating the action potential. Hyperexcitability and mutations of sodium channels are responsible for perception and transmission of inflammatory and neuropathic pain states. In this review, we describe the current knowledge of µ-CTX interacting with the different sodium channels subtypes, the mechanism of action and their potential therapeutic use as analgesic compounds in the clinical management of pain conditions. PMID:28937587

  6. Equivalence of two approaches for modeling ion permeation through a transmembrane channel with an internal binding site

    NASA Astrophysics Data System (ADS)

    Zhou, Huan-Xiang

    2011-04-01

    Ion permeation through transmembrane channels has traditionally been modeled using two different approaches. In one approach, the translocation of the permeant ion through the channel pore is modeled as continuous diffusion and the rate of ion transport is obtained from solving the steady-state diffusion equation. In the other approach, the translocation of the permeant ion through the pore is modeled as hopping along a discrete set of internal binding sites and the rate of ion transport is obtained from solving a set of steady-state rate equations. In a recent work [Zhou, J. Phys. Chem. Lett. 1, 1973 (2010)], the rate constants for binding to an internal site were further calculated by modeling binding as diffusion-influenced reactions. That work provided the foundation for bridging the two approaches. Here we show that, by representing a binding site as an energy well, the two approaches indeed give the same result for the rate of ion transport.

  7. Microscopic origin of gating current fluctuations in a potassium channel voltage sensor.

    PubMed

    Freites, J Alfredo; Schow, Eric V; White, Stephen H; Tobias, Douglas J

    2012-06-06

    Voltage-dependent ion channels open and close in response to changes in membrane electrical potential due to the motion of their voltage-sensing domains (VSDs). VSD charge displacements within the membrane electric field are observed in electrophysiology experiments as gating currents preceding ionic conduction. The elementary charge motions that give rise to the gating current cannot be observed directly, but appear as discrete current pulses that generate fluctuations in gating current measurements. Here we report direct observation of gating-charge displacements in an atomistic molecular dynamics simulation of the isolated VSD from the KvAP channel in a hydrated lipid bilayer on the timescale (10-μs) expected for elementary gating charge transitions. The results reveal that gating-charge displacements are associated with the water-catalyzed rearrangement of salt bridges between the S4 arginines and a set of conserved acidic side chains on the S1-S3 transmembrane segments in the hydrated interior of the VSD. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  8. Quantum subsystems: Exploring the complementarity of quantum privacy and error correction

    NASA Astrophysics Data System (ADS)

    Jochym-O'Connor, Tomas; Kribs, David W.; Laflamme, Raymond; Plosker, Sarah

    2014-09-01

    This paper addresses and expands on the contents of the recent Letter [Phys. Rev. Lett. 111, 030502 (2013), 10.1103/PhysRevLett.111.030502] discussing private quantum subsystems. Here we prove several previously presented results, including a condition for a given random unitary channel to not have a private subspace (although this does not mean that private communication cannot occur, as was previously demonstrated via private subsystems) and algebraic conditions that characterize when a general quantum subsystem or subspace code is private for a quantum channel. These conditions can be regarded as the private analog of the Knill-Laflamme conditions for quantum error correction, and we explore how the conditions simplify in some special cases. The bridge between quantum cryptography and quantum error correction provided by complementary quantum channels motivates the study of a new, more general definition of quantum error-correcting code, and we initiate this study here. We also consider the concept of complementarity for the general notion of a private quantum subsystem.

  9. Level II scour analysis for Bridge 38 (ANDOVT00110038) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont

    USGS Publications Warehouse

    Striker, Lora K.; Hammond, Robert E.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ANDOVT00110038 on State Route 11 crossing the Middle Branch Williams River, Andover, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in south central Vermont. The 5.65-mi2 drainage area is in a predominantly rural and forested basin. Upstream and downstream of the study site banks and overbanks are forested. In the study area, the Middle Branch Williams River has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 44 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 54.0 mm (0.177 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 5, 1996, indicated that the reach was stable. The State Route 11 crossing of the Middle Branch Williams River is a 33-ft-long, two-lane bridge consisting of one 31-foot concrete T-beam span (Vermont Agency of Transportation, written communication, March 29, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 55 degrees to the opening while the measured opening-skew-to-roadway is 45 degrees. There were no scour problems observed during the Level I assessment. Type-4 stone fill (less than 60 inches diameter) and type-3 stone fill (less than 48 inches diameter) was present on the left bank upstream and right bank upstream respectively. Type-2 stone fill (less than 36 inches diameter) was present in the upstream left wing wall area. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 1.8 to 3.4 ft. The worst-case contraction scour occurred at the 500-year flow. Abutment scour ranged from 12.0 to 14.0 ft. The worst-case abutment scour occurred at the 500-year flow at the right abutment. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  10. Level II scour analysis for Bridge 39 (ANDOVT00110039) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ANDOVT00110039 on State Route 11 crossing the Middle Branch Williams River, Andover, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in southern Vermont. The 5.75-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the upstream left bank and downstream right bank. The surface cover on the upstream right and downstream left banks is brush. In the study area, the Middle Branch Williams River has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 58 ft and an average bank height of 8 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 96.8 mm (0.317 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 9, 1996, indicated that the reach was laterally unstable. The State Route 11 crossing of the Middle Branch Williams River is a 43-ft-long, two-lane bridge consisting of one 41-foot concrete-beam span and two additional steel beams on the upstream face (Vermont Agency of Transportation, written communication, March 29, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the opening-skew-to-roadway is 45 degrees. The only scour protection measures at the site was type-2 stone fill (less than 36 inches diameter) at the upstream end of the upstream right wingwall and type-3 stone fill (less than 48 inches diameter) along the entire base length of the upstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 8.9 to 11.2 ft. The worst-case abutment scour occurred at the incipient-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  11. Level II scour analysis for Bridge 28 (ROCHTH00370028) on Town Highway 37, crossing Brandon Brook, Rochester, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Weber, Matthew A.

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure ROCHTH00370028 on Town Highway 37 crossing Brandon Brook, Rochester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from VTAOT files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 8.0-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture on the upstream left overbank although the immediate banks have dense woody vegetation. The upstream right overbank and downstream left and right overbanks are forested. In the study area, the Brandon Brook has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 44 ft and an average bank height of 7 ft. The channel bed material ranges from gravel to cobbles with a median grain size (D50) of 84.2 mm (0.276 ft). The geomorphic assessment at the time of the Level I site visit on April 12, 1995 and Level II site visit on July 8, 1996, indicated that the reach was stable. The Town Highway 37 crossing of the Brandon Brook is a 33-ft-long, one-lane bridge consisting of a 31-foot timber-stringer span (Vermont Agency of Transportation, written communication, March 22, 1995). The opening length of the structure parallel to the bridge face is 29.6 ft. The bridge is supported by vertical, timber log cribbing abutments with wingwalls. The channel is skewed approximately 5 degrees to the opening while the computed opening-skew-to-roadway is zero degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the upstream left wingwall and the left abutment during the Level I assessment. The only scour protection measure at the site was type-5 protection, an artificial levee, extending along the upstream right bank to the end of the upstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was zero ft. Left abutment scour ranged from 7.1 to 9.9 ft where the worst-case scour occurred at the 500-year discharge. Right abutment scour ranged from 4.4 to 5.1 ft where the worst-case scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results.” Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein

  12. Level II scour analysis for Bridge 44 (LINCTH00330044) on Town Highway 33, crossing the New Haven River, Lincoln, Vermont

    USGS Publications Warehouse

    Burns, Ronda L.; Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure LINCTH00330044 on Town Highway 33 crossing the New Haven River, Lincoln, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.The site is in the Green Mountain section of the New England physiographic province in west-central Vermont. The 6.3-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest.In the study area, the New Haven River has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 56 ft and an average bank height of 6 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 101.9 mm (0.334 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 10, 1996, indicated that the reach was stable.The Town Highway 33 crossing of the New Haven River is a 33-ft-long, one-lane bridge consisting of one 31-foot timber-beam span (Vermont Agency of Transportation, written communication, December 14, 1995). The opening length of the structure parallel to the bridge face is 29.3 ft. The bridge is supported by vertical, wood-beam crib abutments with wingwalls. The channel is skewed approximately 25 degrees to the opening while the opening-skew-to-roadway is zero degrees.A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. The scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) at the downstream end of the downstream left wingwall and along the downstream right bank, type-2 stone fill (less than 36 inches diameter) along the upstream right bank and type-3 stone fill (less than 48 inches diameter) at the upstream end of the upstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled flows ranged from 0.0 to 1.3 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was less than the 100-year discharge. Abutment scour ranged from 9.4 to 12.6 ft. The worst-case abutment scour occurred at the 100-year discharge for the left abutment and at the incipient overtopping discharge for the right abutment. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  13. Level II scour analysis for Bridge 46 (CHESVT00110046) on Vermont State Route 11, crossing the Middle Branch Williams River, Chester, Vermont

    USGS Publications Warehouse

    Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure CHESVT00110046 on State Route 11 crossing the Middle Branch Williams River, Chester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.The site is in the Green Mountain and New England Upland sections of the New England physiographic province in southeastern Vermont. The 28.0-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forested on the upstream left and downstream right overbanks. The upstream right and downstream left overbanks are pasture while the immediate banks have dense woody vegetation.In the study area, the the Middle Branch Williams River has an incised, sinuous channel with a slope of approximately 0.013 ft/ft, an average channel top width of 81 ft and an average bank height of 11 ft. The channel bed material ranges from gravel to bedrock with a median grain size (D50) of 70.7 mm (0.232 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 12, 1996, indicated that the reach was stable.The State Route 11 crossing of the Middle Branch Williams River is a 118-ft-long, two-lane steel stringer type bridge consisting of a 114-foot steel plate deck (Vermont Agency of Transportation, written communication, March 29, 1995). The opening length of the structure parallel to the bridge face is 109 ft.The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the opening-skew-to-roadway is 50 degrees.A scour hole 2 ft deeper than the mean thalweg depth was observed 128 feet downstream during the Level I assessment. Type-1 (less than 1 foot) stone fill protects the downstream right wingwall. Type-2 (less than 3 ft diameter) stone fill protects the upstream right wingwall, the left and right abutments, the upstream left and right road embankments. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.There was no computed contraction scour for any modelled flows. Abutment scour ranged from 7.0 to 10.3 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  14. Level II scour analysis for Bridge 8 (NEWFTH00010008) on Town Highway 1, crossing Wardsboro Brook, Newfane, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Degnan, James

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure NEWFTH00010008 on Town Highway 1 crossing Wardsboro Brook, Newfane, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (Federal Highway Administration, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the New England Upland section of the New England physiographic province in southestern Vermont. The 6.91-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the upstream right overbank and downstream left and right overbanks. The surface cover on the upstream left overbank is pasture. In the study area, Wardsboro Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 63 ft and an average bank height of 9 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 95.4 mm (0.313 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 21, 1996, indicated that the reach was stable. The Town Highway 1 crossing of the Wardsboro Brook is a 32-ft-long, two-lane bridge consisting of a 26-foot concrete tee-beam span (Vermont Agency of Transportation, written communication, April 6, 1995). The opening length of the structure parallel to the bridge face is 26.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the computed opening while the openingskew-to-roadway is 45 degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) along the upstream right bank, and type-2 stone fill (less than 36 inches diameter) along the upstream left bank and the upstream ends of the upstream left and right wingwalls. A stone wall extends along the downstream right bank from the end of the downstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.1 to 3.9 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 11.1 to 12.9 ft. Right abutment scour ranged from 4.3 to 4.8 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  15. Level II scour analysis for Bridge 67 (MTHOTH00120067) on Town Highway 12, crossing Freeman Brook, Mount Holly, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Severance, Timothy

    1998-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure MTHOTH00120067 on Town Highway 12 crossing Freeman Brook, Mount Holly, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Green Mountain section of the New England physiographic province in south-central Vermont. The 11.4-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forested. In the study area, Freeman Brook has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 51 ft and an average bank height of 6 ft. The channel bed material ranges from sand to boulders with a median grain size (D50) of 55.7 mm (0.183 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 5, 1995, indicated that the reach was stable. The Town Highway 12 crossing of Freeman Brook is a 34-ft-long, two-lane bridge consisting of a 30-foot prestressed concrete-slab span (Vermont Agency of Transportation, written communication, March 15, 1995). The opening length of the structure parallel to the bridge face is 29.5 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 50 degrees to the opening while the opening-skew-to-roadway is 15 degrees. Along the upstream right wingwall, the right abutment and the downstream right wingwall, a scour hole approximately 1.0 to 2.0 ft deeper than the mean thalweg depth was observed during the Level I assessment. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) along the downstream end of the downstream right wingwall; type-2 stone fill (less than 36 inches diameter) along the upstream left wingwall, the left abutment, the downstream left wingwall and the upstream left and right banks; type- 3 stone fill (less than 48 inches diameter) along the downstream left and right banks; and type-4 stone fill (less than 60 inches diameter) along the upstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 2.6 to 3.9 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 7.9 to 10.0 ft. Right abutment scour ranged from 12.7 to 15.2 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  16. Level II scour analysis for Bridge 36 (STOWTH00430036) on Town Highway 43, crossing Miller Brook, Stowe, Vermont

    USGS Publications Warehouse

    Striker, Lora K.; Wild, Emily C.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure STOWTH00430036 on Town Highway 43 crossing the Miller Brook, Stowe, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in north central Vermont. The 5.5-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is predominantly forested. In the study area, the Miller Brook has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 43 ft and an average bank height of 7 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 70.4 mm (0.231 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 15, 1996, indicated that the reach was stable. The Town Highway 43 crossing of the Miller Brook is a 24-ft-long, two-lane bridge consisting of one 21-foot steel-beam span (Vermont Agency of Transportation, written communication, October 13, 1995). The opening length of the structure parallel to the bridge face is 21.5 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening and the computed opening-skew-to-roadway is also 10 degrees. The footing on the left abutment was exposed 2.5 ft and the footing on the right abutment was exposed 3.0 ft during the Level I assessment. Scour protection measures at the site were type-4 stone fill (less than 60 inches diameter) on the left and right bank upstream, type-3 stone fill (less than 48 inches diameter) along the entire base length of the upstream right wingwall, right abutment, and type-2 stone fill (less than 36 inches diameter) along the entire base length of the downstream right wingwall, and left and right banks downstream. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.9 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 3.1 to 6.5 ft. The worst-case abutment scour occurred at the 100-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  17. Level II scour analysis for Bridge 10 (CHESTH00030010) on Town Highway 3 (VT 35), crossing the South Branch of Williams River, Chester, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Hammond, Robert E.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure CHESTH00030010 on Town Highway 3 (VT 35) crossing the South Branch Williams River, Chester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 9.44-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest.In the study area, the South Branch Williams River has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 67 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 69.0 mm (0.226 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 26-27, 1996, indicated that the reach was stable.The Town Highway 3 (VT 35) crossing of the South Branch Williams River is a 69-foot-long, two-lane bridge consisting of one 67-foot steel-stringer span with a concrete deck (Vermont Agency of Transportation, written communication, August 23, 1994). The opening length of the structure parallel to the bridge face is 64.5 ft. The bridge is supported by vertical, concrete abutments with spill-through embankments. The channel is skewed approximately 50 degrees to the opening while the opening-skew-to-roadway is 30 degrees.The scour protection (spill-through abutments) measured at the site was type-3 stone fill (less than 48 inches diameter) extending the entire base length and around the ends of the left and right abutments. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for modelled flows ranged from 0.8 to 3.8 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge. Left abutment scour ranged from 13.3 to 14.9 ft. The worst-case scour at the left abutment occurred at the 500-year discharge. Right abutment scour ranged from 4.1 to 6.0 ft. The worst-case scour at the right abutment occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  18. Level II scour analysis for Bridge 36 (DUXBTH00040036) on Town Highway 4, crossing Crossett Brook, Duxbury, Vermont

    USGS Publications Warehouse

    Wild, Emily C.; Degnan, James R.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure DUXBTH00040036 on Town Highway 4 crossing the Crossett Brook, Duxbury, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.The site is in the Green Mountain section of the New England physiographic province in north-central Vermont. The 4.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover on the upstream left overbank is pasture. The upstream and downstream right overbanks are forested. The downstream left overbank is brushland, while the immediate banks have dense woody vegetation.In the study area, the Crossett Brook has an incised, sinuous channel with a slope of approximately 0.006 ft/ft, an average channel top width of 55 ft and an average bank height of 9 ft. The channel bed material ranges from gravel to bedrock with a median grain size (D50) of 51.6 mm (0.169 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 1, 1996, indicated that the reach was stable.The Town Highway 4 crossing of the Crossett Brook is a 29-ft-long, two-lane bridge consisting of a 26-foot concrete slab span (Vermont Agency of Transportation, written communication, October 13, 1995). The opening length of the structure parallel to the bridge face is 26 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 35 degrees to the opening while the computed opening-skew-to-roadway is 5 degrees.A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the upstream left wingwall and the right abutment during the Level I assessment. Scour countermeasures at the site includes type-2 stone fill (less than 36 inches diameter) at the upstream end of the upstream left and right wingwalls and the upstream left and right banks and road embankments. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.Contraction scour for all modelled flows ranged from 0.0 to 1.7 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.4 to 8.3 ft. Right abutment scour ranged from 6.0 to 7.0 ft. The worst-case left and right abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  19. Level II scour analysis for Bridge 12 (SUNDFLR0030012) on Forest Land Road 3, crossing Roaring Branch Brook, Sunderland, Vermont

    USGS Publications Warehouse

    Flynn, Robert H.; Medalie, Laura

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure SUNDFLR0030012 on Forest Land Road (FLR) 3 (FAS 114) crossing Roaring Branch Brook, Sunderland, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the Green Mountain section of the New England physiographic province in southwestern Vermont. The 4.93-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is dense forest along the left bank and primarily shrubs and trees along the right bank, both upstream and downstream of the bridge. In the study area, Roaring Branch Brook has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 33 ft and an average bank height of 4 ft. The channel bed material ranges from cobble to bedrock with a median grain size (D50) of 139 mm (0.457 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 30, 1996, indicated that the reach was stable. Forest Land Road 3 (FAS 114) crossing of Roaring Branch Brook is a 37-ft-long, two-lane bridge consisting of one 35-foot steel-beam span (Vermont Agency of Transportation, written communication, December 14, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 30 degrees to the opening while the opening-skew-to-roadway is 15 degrees. The scour protection measures at the site included type-3 stone fill (less than 48 inches diameter) along the left and right abutments, along the upstream left and downstream right wing walls and along the downstream right bank. Type-4 (less than 60 inches diameter) stone fill was found along the upstream right and downstream left wingwalls and along the downstream left bank. Type-2 (less than 36 inches diameter) stone fill scour protection was found along the upstream left and right banks. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows was calculated to be 0.0 ft. Abutment scour ranged from 4.3 to 10.4 ft. The worst-case abutment scour occurred at the 500-year discharge along the right abutment. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

  20. Level II scour analysis for Bridge 20 (GRAFTH00010020) on Town Highway 1, crossing the Saxtons River, Grafton Vermont

    USGS Publications Warehouse

    Boehmler, Erick M.; Burns, Ronda L.

    1997-01-01

    This report provides the results of a detailed Level II analysis of scour potential at structure GRAFTH00010020 on Town Highway 1 crossing the Saxtons River, Grafton, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D. The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 33.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream of the bridge and shrub and brush downstream. In the study area, the Saxtons River has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 97 ft and an average bank height of 2 ft. The predominant channel bed material is gravel with a median grain size (D50) of 58.6 mm (0.192 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 21, 1996, indicated that the reach was laterally unstable due to distinctive cut bank development on the upstream right bank and point bar development on the upstream left bank and downstream right bank. The Town Highway 1 crossing of the Saxtons River is a 191-ft-long, two-lane bridge consisting of three steel-beam spans (Vermont Agency of Transportation, written communication, March 29, 1995). The bridge is supported by vertical, concrete abutments with spill-through embankments and two piers. The channel is skewed approximately 40 degrees to the opening. The opening-skew-to-roadway is 45 degrees in the VTAOT records but measured 50 degrees from surveyed points. The scour protection measures at the site were type-1 stone fill (less than 12 inches diameter) on the left abutment, type-2 stone fill (less than 36 inches diameter) on the right abutment and downstream right bank, and a stone wall is noted on the left bank downstream. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.0 to 0.9 feet. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 8.0 to 14.9 feet. The worst-case abutment scour occurred at the 500-year discharge for the right abutment. There are two piers for which computed pier scour ranged from 8.7 to 26.0 feet. The left and right piers in this report are presented as pier 1 and pier 2 respectively. The worst-case pier scour occurred at pier 2 for the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

Some links on this page may take you to non-federal websites. Their policies may differ from this site.
Top