A review of recent advances in numerical modelling of local scour problems

DEFF Research Database (Denmark)

Sumer, B. Mutlu

2014-01-01

A review is presented of recent advances in numerical modelling of local scour problems. The review is organized in five sections: Highlights of numerical modelling of local scour; Influence of turbulence on scour; Backfilling of scour holes; Scour around complex structures; and Scour protection ...

Numerical simulation of scour by a wall jet downstream of a solid apron

Energy Technology Data Exchange (ETDEWEB)

Barron, R.M. [Univ. of Windsor, Fluid Dynamics Research Inst., Windsor, Ontario (Canada)]. E-mail: az3@uwindsor.ca; Neyshabouri, S.A.A.S. [Univ. of Tarbiat Modarres, Dept. of Civil Engineering, Tehran (Iran, Islamic Republic of)]. E-mail: salehi@modares.ac.ir

2003-07-01

The time consuming and expensive nature of experimental research on scouring processes caused by flowing water makes it attractive to develop numerical tools for the prediction of the interaction of the fluid flow and the movable bed. In this paper the numerical simulation of scour caused by a wall jet flowing over a solid apron is presented. The flow is assumed to be two-dimensional, and the alluvium is cohesionless. The solution process, repeated at each time step, involves simulation of a turbulent wall jet flow, determination of the convection-diffusion of sand concentration, and prediction of the bed deformation. For simulation of the jet flow, the governing equations for momentum, mass balance and turbulent parameters are solved by the finite volume method. The SIMPLE scheme with momentum interpolation is used for pressure correction. A convection-diffusion equation is solved for sediment concentration. A boundary condition for concentration at the bed, which takes into account the effect of bed-load, is implemented. The time rate of deposition and scour at the bed is obtained by solving the continuity equation for sediment. A meshing technique is devised to deal with the movement of the bed adjacent to the rigid apron. Comparison of the simulation results with available experimental data shows favorable agreement for the time evolution of the scour hole and for the maximum scour depth. (author)

Eco-friendly design of scour protection: potential enhancement of ecological functioning in offshore wind farms

NARCIS (Netherlands)

Lengkeek, Wouter; Didderen, K.; Teunis, M.; Driessen, F.; Coolen, J.W.P.; Bos, O.G.; Vergouwen, S.A.; Raaijmakers, T.; Vries, de M.B.; Koningsveld, van M.

2017-01-01

The aim of this study is to explore the possibilities to implement ‘Building with North Sea Nature’ in offshore infrastructures in the North Sea by providing guidelines for the eco-friendly design of scour protection structures around monopiles in planned wind farms to enhance ecological

Assessment of Foundation Design for Offshore Monopiles Unprotected Against Scour

DEFF Research Database (Denmark)

Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo

2013-01-01

When designing offshore monopiles without scour protection, the stiffness of the foundation will vary with time due to the dependency of the scour depth on current and sea conditions. Currently, design regulations of organizations such as Det Norske Veritas (DNV) and the International Organization...... for Standardization (ISO) recommend the use of the most extreme local scour depth as the design scour depth. This is a conservative approach, because the scour depth depends on the sea conditions and because the equilibrium scour depth is low during moderate to extreme wave loading. In this paper the effect of using...... expected scour depths when designing for the ultimate limit state and the fatigue limit state is illustrated by means of a desk study....

Scour at the round head of a rubble-mound breakwater

DEFF Research Database (Denmark)

Fredsøe, Jørgen; Sumer, B. Mutlu

1997-01-01

This study complements the investigation on scour around the head of a breakwater, reported in the companion paper where the case of vertical-wall breakwater was considered, The present study deals with the case of rubble-mound breakwater. Two key mechanisms with regard to the scour processes......, and the acceleration due to gravity, g, appears to be the main governing parameter regarding the breaker-induced scour. The scour depth increases with increasing values of these parameters. The conventional stone protection is investigated in the study. An empirical formula is developed for the extent...

Flood scour monitoring system using fiber Bragg grating sensors

Science.gov (United States)

Lin, Yung Bin; Lai, Jihn Sung; Chang, Kuo Chun; Li, Lu Sheng

2006-12-01

The exposure and subsequent undermining of pier/abutment foundations through the scouring action of a flood can result in the structural failure of a bridge. Bridge scour is one of the leading causes of bridge failure. Bridges subject to periods of flood/high flow require monitoring during those times in order to protect the traveling public. In this study, an innovative scour monitoring system using button-like fiber Bragg grating (FBG) sensors was developed and applied successfully in the field during the Aere typhoon period in 2004. The in situ FBG scour monitoring system has been demonstrated to be robust and reliable for real-time scour-depth measurements, and to be valid for indicating depositional depth at the Dadu Bridge. The field results show that this system can function well and survive a typhoon flood.

Wave scour around structures

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Fredsøe, Jørgen

1999-01-01

This review (of scour around marine structures) is organized in seven main sections: Basic concepts; Tunnel erosion; Two- and three-dimensional scour around pipelines; Scour around piles (slender bodies), including pile groups; Scour around complex structures; Scour around large, vertical cylinders...

Scour around an offshore windturbine

NARCIS (Netherlands)

Louwersheimer, W.F.; Verhagen, H.J.; Olthof, J.

2007-01-01

During the construction of the first Dutch offshore wind farm prototype measurements were performed. These measurements were aimed to monitor the behaviour of the granular filter layer of the scour protection around the mono-piles upon which the wind turbines are founded. These measurements were

Wall roughness effects on flow and scouring in curved channels with gravel bed

OpenAIRE

Hersberger, Daniel S.

2002-01-01

Wall roughness effects on flow and scouring in curved channels with gravel bed In the narrow valleys in Alpine regions, rivers frequently flow across constructed zones, passing through villages and cities. Due to limited space, the protection from high floods often needs to be ensured by protection walls. During floods, these protection walls may be endangered by scour phenomena, especially if they are located in bends. In the past, the potential danger of underscoured structures was reduced ...

Prevention of Bridge Scour with Non-uniform Circular Piers Plane under Steady Flows

Science.gov (United States)

Chen, Hsing-Ting; Wang, Chuan-Yi

2017-04-01

River bed scour and deposit variation extremely severe because of most of rivers are steep and rapid flows, and river discharge extremely unstable and highly unsteady during different seasons in Taiwan. In addition to the obstruction of piers foundation, it causes local scour and threatens the safety of bridges. In the past, riprap, wire gabion or wrap pier works were adopted as the protections of piers foundation, but there were no effectual outcomes. The events of break off piers still happen sometimes. For example, typhoon Kalmaegi (2008) and Morakot (2009) caused heavy damages on Ho-Fon bridge in the Da-jia river and Shuang-Yuan bridge in the Kao-Ping river, respectively. Accordingly, to understand the piers scour system and propose an appropriate protection of piers foundation becomes an important topic for this study currently. This research improves the protection works of the existing uniform bridge pier (diameter D) to ensure the safety of the bridge. The non-uniform plane of circular piers (diameter D*) are placed on the top of a bridge pier foundation to reduce the down flow impacting energy and scour by its' surface roughness characteristics. This study utilize hydraulic models to simulate local scour depth and scour depth change with time for non-uniform pier diameter ratio D/D* of 0.3,0.4,0.5,0.6,0.7 and 0.8, and different type pier and initial bed level (Y) relative under the foundation top elevation under steady flows of V/Vc=0.95,0.80 and 0.65. The research results show that the scour depth increases with an increase of flow intensity (V/Vc) under different types of steady flow hydrographs. The scour depth decreases with increase of initial bed level (Y=+0.2D*,0D*and -0.2D*) relative under the foundation top elevation of the different type pier. The maximum scour depth occurred in the front of the pier for all conditions. Because of the scouring retardation by the non-uniform plane of foundation, the scour depth is reduced for the un-exposed bridge

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

Science.gov (United States)

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.

Safety Performance Evaluations for the Vehicle Based Movable Barriers Using Full Scale Crash Tests

Directory of Open Access Journals (Sweden)

Jin Minsoo

2017-01-01

Full Text Available The present study aims to develop a prototype of large-size movable barriers to protect roadside workers from incoming vehicles to the road work area with the following functions: maximization of work space in the right and left directions, convenient mobility, and minimization of impact without modification of the inside of movable barriers into traffic lanes and perform safety performance assessment on passengers through full scale crash tests. The large movable barrier was divided into folder type and telescope type and the development stage was now at the prototype phase. A full scale crash test was conducted prior to certification test at a level of 90%. The full scale crash test result showed that both types of folder type movable barrier and telescope type movable barrier satisfied the standard of the passenger safety performance evaluation at a level of 90%.

Development of scour in non-cohesive sediments under a poorly erodible top layer

OpenAIRE

Van Zuylen, J.A.; Sloff, C.J.

2015-01-01

This study deals with the development of deep scour holes in the river bed of the Dutch Rhine delta in the Netherlands. Assessment of multi-beam surveys, laboratory-flume experiments, and 3D numerical modelling, shows how fast this type of scour holes grows in depth and width. These typical scour holes are found in the tidal deltaic rivers that experience a general incision. This erosion decreases the thickness of the erosion resistant clay/peat layer that is covering and protecting the under...

Flume experiments on scour downstream of wood stream restoration structures

Science.gov (United States)

Pagliara, Stefano; Kurdistani, Sahameddin Mahmoudi

2017-02-01

River restoration aims to improve physical natural form and processes of a river. Techniques to control the riverbed, stabilize channel alignment, protect stream banks, and rebuild the natural habitat are an important part of river restoration projects. Rivers can be stabilized and habitat restored through techniques such as rebuilding meanders and pool-riffle sequences and managing large wood. Structures that limit channel width to accelerate the normal flows through the constricted section are referred to as stream deflectors. Single-wing, double-wing and triangular deflectors are the most commonly used types of this measure. Log-frame deflectors consist of a triangular log frame filled with rock. Deflector constructions singly or in series in low gradient meandering streams, divert base flows toward the center of the channel and, under certain conditions, increase the depth and velocity of flow thereby creating scour pools and enhancing fish habitat. Scour characteristics and morphologies downstream of log-frame deflectors have been analyzed at the hydraulic laboratory of the University of Pisa. All experiments have been carried out in clear water conditions. The results showed that the tailwater depth plays an important role on scour characteristics. In addition, it was experimentally proven that using log-frame deflectors instead of log-deflectors result in a better river bank protection. In this case, for all the tested hydraulic conditions, the scour hole never occurred close to the channel bank. Useful empirical relationships have been proposed in order to evaluate the main features of the scour geometry.

Environmental protection stability of river bed and banks using convex, concave, and linear bed sills.

Science.gov (United States)

Keshavarzi, Alireza; Noori, Lila Khaje

2010-12-01

River bed scourings are a major environmental problem for fish and aquatic habitat resources. In this study, to prevent river bed and banks from scouring, different types of bed sills including convex, concave and linear patterns were installed in a movable channel bed in a laboratory flume. The bed sills were tested with nine different arrangements and under different flow conditions. To find the most effective bed sill pattern, the scouring depth was measured downstream of the bed sill for a long experimental duration. The scour depth was measured at the middle and at the end of each experimental test for different ratios of the arch radius to the channel width [r/w]. The experimental results indicated that the convex pattern with r/w=0.35 produced minimum bed scouring depth at the center line whereas the concave pattern with r/w=0.23 produced the minimum scour depth at the wall banks. Therefore, the convex pattern was the most effective configuration for prevention of scouring at the center line of the river while the concave pattern was very effective to prevent scouring at the river banks. These findings can be suggested to be used in practical applications.

Time-wise variation of scouring at bridge abutments

Indian Academy of Sciences (India)

provides useful information for the degree of scour counter-measure to be imple- mented against ..... the extension of the area of protection as well as the size, layer thickness, and surface elevation .... 275, School of Engineering, University of.

Proceedings of the ice scour and Arctic marine pipelines workshop

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-11-01

This conference was organized to discuss the challenges facing engineers in Arctic offshore oil and gas operations, particularly those dealing with the design, installation and operation of offshore pipelines. Adding to the usual engineering considerations, formidable enough in themselves, Arctic offshore pipelines also face constraints due to permafrost, ice cover, and ice scouring from icebergs. In addition to an examinations of the roles played by these constraints, the forces and deformation mechanisms experienced by different soils during ice scouring events, modeling the scouring process and the application of models to the issue of pipeline burial and protection were other topics that were addressed by various speakers. Some of the regulatory concerns regarding issues for Arctic pipelines were also discussed. refs., tabs., figs.

Maintaining the Link to The Floodplain: Scour Dynamics in Crevasses

Science.gov (United States)

Esposito, C. R.; Liang, M.; Yuill, B. T.; Meselhe, E. A.

2017-12-01

In river deltas, crevasses are the primary geomorphic feature that traverse the levee, connecting the river to its floodplain and facilitating the transfer of water, sediment, and chemical constituents from the trunk channel. Despite their fundamental position linking river and floodplain, the factors that are important to crevasse evolution are not well understood, and their enumeration is the subject of active research across multiple earth surface process subfields. Crevasses are often associated with a zone of intense scour proximal to the trunk channel. Surprisingly little is known about the morphological dynamics in this zone, but there is evidence from studies of river avulsion that scour zone evolution plays an important role in determining crevasse sustainability. Here we use Delft3D to simulate the development of managed crevasse splays - river diversions - for the purpose of landscape management in the Mississippi River Delta. Our model runs vary the erodibility of the substrate in the receiving basin and the extent and location of erosion protection along the conveyance channel. We find that substrate erodibility in the basin plays a critical role in determining the long-term performance of sediment diversions. Crevasses that create large scours tend to maintain their performance over several decades, but those that only create small scours are subject to rapidly declining performance as the scour pit fills in with coarse sediments. Finally, we compare the evolution of our modeled scour zone to the West Bay Sediment Diversion, where regular bathymetric surveys have documented the evolution of the scour zone since 2004.

Potential scour for marine current turbines based on experience of offshore wind turbine

International Nuclear Information System (INIS)

Chen, L; Lam, W H; Shamsuddin, A H

2013-01-01

The oceans have tremendous untapped natural resources. These sources are capable to make significant contribution to our future energy demands. Marine current energy offers sustainable and renewable alternative to conventional sources. Survival problems of Marine Current Turbines (MCTs) need to be addressed due to the harsh marine environment. The analogous researches in wind turbine have been conducted. Some of the results and knowledge are transferable to marine current energy industry. There still exist some gaps in the state of knowledge. Scour around marine structures have been well recognised as an engineering issue as scour is likely to cause structural instability. This paper aims to review different types of foundation of MCTs and potential scour and scour protection around these foundations based on the experience of offshore wind turbine farm.

The South Carolina bridge-scour envelope curves

Science.gov (United States)

Benedict, Stephen T.; Feaster, Toby D.; Caldwell, Andral W.

2016-09-30

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations to evaluate historical, riverine bridge scour in the Piedmont and Coastal Plain regions of South Carolina. These investigations included data collected at 231 riverine bridges, which lead to the development of bridge-scour envelope curves for clear-water and live-bed components of scour. The application and limitations of the South Carolina bridge-scour envelope curves were documented in four reports, each report addressing selected components of bridge scour. The current investigation (2016) synthesizes the findings of these previous reports into a guidance manual providing an integrated procedure for applying the envelope curves. Additionally, the investigation provides limited verification for selected bridge-scour envelope curves by comparing them to field data collected outside of South Carolina from previously published sources. Although the bridge-scour envelope curves have limitations, they are useful supplementary tools for assessing the potential for scour at riverine bridges in South Carolina.

Bridge Scour Technology Transfer

Science.gov (United States)

2018-01-24

Scour and flooding are the leading causes of bridge failures in the United States and therefore should be monitored. New applications of tools and technologies are being developed, tested, and implemented to reduce bridge scour risk. The National Coo...

Global and local scour at pile groups

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Bundgaard, Klavs; Fredsøe, Jørgen

2005-01-01

This paper presents the results of an experimental investigation on scour around pile groups with different configurations exposed to steady current. Two kinds of tests were carried out: rigid-bed tests and actual scour tests. In these, the mean and turbulence properties of the flow were measured...... across the pile groups. The pile-group configurations were such that the global scour was distinguished from the local scour. The results show that the global scour can be quite substantial....

Global and local scour at pile groups

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Bundgaard, Klavs; Fredsøe, Jørgen

2005-01-01

This paper presents the results of an experimental investigation on scour around pile groups with different configurations exposed to steady current. Two kinds of tests were carried out: (1) Rigid-bed tests, and (2) Actual scour tests. In the former tests, the mean and turbulence properties...... of the flow were measured across the pile groups. The pile group configurations were such that the global scour was distinguished from the local scour. The results show that the global scour can be quite substantial....

Level II scour analysis for Bridge 28 (ROCHTH00370028) on Town Highway 37, crossing Brandon Brook, Rochester, Vermont

Science.gov (United States)

Wild, Emily C.; Weber, Matthew A.

1998-01-01

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

78 FR 13747 - Safety Advisory 2013-01; Passing Stop Signals Protecting Movable Bridges

Science.gov (United States)

2013-02-28

... Association Manual for Railway Engineering. 2. Evaluate operating rules and procedures that permit the...: (1) Evaluate the design and construction of existing movable bridges to determine if effective span... perform these duties. FOR FURTHER INFORMATION CONTACT: Carlo M. Patrick, Staff Director, Rail and...

Scour around bridge piers in the stage hydrograph

Energy Technology Data Exchange (ETDEWEB)

Ahn, Sang Jin; Kim, Ung Yong [Chungbuk National University, Chongju (Korea, Republic of); Yon, Kee Seuk; Kim, Jong Sub [Taejon University of Technology, Taejon (Korea, Republic of)

1997-08-31

This study aims at examining closely the scour around a pier due to irregular water stage changes during flood. At the Sangye bridge is located lowermost downstream of the Bocheong stream in the Kum River, the IHP experimental watershed. For this purpose, we have analyzed the change of scour depths due to stage hydrographs of experimental basin by a simulation. To examine the scour phenomenon around a pier due to irregular stage change in flood, we have analyzed the change of scour depth corresponding to stage hydrograph of field watershed after verification of model channel. From this study, the following conclusions are made: First, in case of predicting the maximum scour depth around a pier with stage hydrograph in the state of steady flow, we should choose the highest stage. Second, after increasing the stage, the equilibrium scour depth became smaller than the maximum scour depth. therefore, in case of estimating the maximum scour depth in rivers, it is recommended that we should consider additional scour depth which is reduced by infilling the sediments. (author). 25 refs., 6 tabs., 11 figs.

Local scour at abutments: A review

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

On the other hand, live-bed scour occurs when the scour hole is ... The primary vortex is elliptical in shape, with an inner core region being a .... The primary vortex is strong upstream of the abutment (see sections A–C) ...... Cardoso A H, Bettess R 1999 Effects of time and channel geometry on scour at bridge abutments. J.

Reliability Analysis of Free Jet Scour Below Dams

Directory of Open Access Journals (Sweden)

Chuanqi Li

2012-12-01

Full Text Available Current formulas for calculating scour depth below of a free over fall are mostly deterministic in nature and do not adequately consider the uncertainties of various scouring parameters. A reliability-based assessment of scour, taking into account uncertainties of parameters and coefficients involved, should be performed. This paper studies the reliability of a dam foundation under the threat of scour. A model for calculating the reliability of scour and estimating the probability of failure of the dam foundation subjected to scour is presented. The Maximum Entropy Method is applied to construct the probability density function (PDF of the performance function subject to the moment constraints. Monte Carlo simulation (MCS is applied for uncertainty analysis. An example is considered, and there liability of its scour is computed, the influence of various random variables on the probability failure is analyzed.

Unknown foundation determination for scour.

Science.gov (United States)

2012-04-01

Unknown foundations affect about 9,000 bridges in Texas. For bridges over rivers, this creates a problem : regarding scour decisions as the calculated scour depth cannot be compared to the foundation depth, and a : very conservative costly approach m...

Level II scour analysis for Bridge 18 (SHEFTH00410018) on Town Highway 41, crossing Millers Run, Sheffield, Vermont

Science.gov (United States)

Wild, Emily C.; Boehmler, Erick M.

1997-01-01

opening-skewto-roadway is 5 degrees, while it is zero degrees in the historical form. A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the left abutment during the Level I assessment. The scour protection measure at the site includes type-1 stone fill (less than 12 inches diameter) along the upstream right wingwall and the upstream left wingwall. Type-2 stone fill (less than 36 inches diameter) extends along the downstream end of the downstream left wingwall, the upstream right bank and the downstream left bank. The downstream right bank is protected by type-2 stone fill and a stone masonry 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) 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 0.2 to 1.8 ft. The worst-case contraction scour occurred at the 100-year and 500-year discharges. Left abutment scour ranged from 14.1 to 16.4 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 6.9 to 9.3 ft. The worst-case right abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to

A-jacks and Aquawrap installations in Utah : scour revetment performance evaluation, final report, December 2009.

Science.gov (United States)

2009-12-01

This is a performance evaluation report for A-Jacks, an articulated concrete block designed to protect bridge elements exposed to the river scouring forces, and for Aquawrap, a glass fiber reinforced polymer designed to protect and strengthen bridge ...

Temporal variation of clear-water scour at compound Abutments

Directory of Open Access Journals (Sweden)

Aminuddin Ab. Ghani

2016-12-01

Full Text Available Most of actual abutments in rivers are built on foundation, while there is limited number of study available on the effects of the foundation on the local scour. In this study, temporal variation of local scour around compound abutment was investigated experimentally under clear-water conditions. The results showed that a suitable level of foundation is able to decrease the scour depth and increase scour time during the flood events. The trend of temporal scour depth at compound pier and abutment is similar. The scour depth develops to top of foundation quickly, and then the foundation postpones the scour development (lag–time. Duration of lag–time depends on the foundation level, velocity ratio (U/Uc and foundation dimension. This study highlights that proper design of foundation level increases duration of scouring and provides enough time to treat bridge foundation after the flood events.

Streambed scour of salmon spawning habitat in a regulated river influenced by management of peak discharge

Science.gov (United States)

Gendaszek, Andrew S.; Burton, Karl D.; Magirl, Christopher S.; Konrad, Christopher P.

2017-01-01

In the Pacific Northwest of the United States, salmon eggs incubating within streambed gravels are susceptible to scour during floods. The threat to egg-to-fry survival by streambed scour is mitigated, in part, by the adaptation of salmon to bury their eggs below the typical depth of scour. In regulated rivers globally, we suggest that water managers consider the effect of dam operations on scour and its impacts on species dependent on benthic habitats.We instrumented salmon-spawning habitat with accelerometer scour monitors (ASMs) at 73 locations in 11 reaches of the Cedar River in western Washington State of the United States from Autumn 2013 through the Spring of 2014. The timing of scour was related to the discharge measured at a nearby gage and compared to previously published ASM data at 26 locations in two reaches of the Cedar River collected between Autumn 2010 and Spring 2011.Thirteen percent of the recovered ASMs recorded scour during a peak-discharge event in March 2014 (2-to 3-year recurrence interval) compared to 71% of the recovered ASMs during a higher peak-discharge event in January 2011 (10-year recurrence interval). Of the 23 locations where ASMs recorded scour during the 2011 and 2014 deployments, 35% had scour when the discharge was ≤87.3 m3/s (3,082 ft3/s) (2-year recurrence interval discharge) with 13% recording scour at or below the 62.3 m3/s (2,200 ft3/s) operational threshold for peak-discharge management during the incubation of salmon eggs.Scour to the depth of salmon egg pockets was limited during peak discharges with frequent (1.25-year or less) recurrence intervals, which managers can regulate through dam operations on the Cedar River. Pairing novel measurements of the timing of streambed scour with discharge data allows the development of peak-discharge management strategies that protect salmon eggs incubating within streambed gravels during floods.

Level II scour analysis for Bridge 38 (JERITH0020038) on Town Highway 20, crossing the Lee River, Jericho, Vermont

Science.gov (United States)

Wild, Emily C.; Degnan, James R.

1997-01-01

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

Temporal variation of clear-water scour at compound Abutments

OpenAIRE

Aminuddin Ab. Ghani; Reza Mohammadpour

2016-01-01

Most of actual abutments in rivers are built on foundation, while there is limited number of study available on the effects of the foundation on the local scour. In this study, temporal variation of local scour around compound abutment was investigated experimentally under clear-water conditions. The results showed that a suitable level of foundation is able to decrease the scour depth and increase scour time during the flood events. The trend of temporal scour depth at compound pier and abut...

23 CFR 650.809 - Movable span bridges.

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Movable span bridges. 650.809 Section 650.809 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed bridge...

Level II scour analysis for Bridge 17 (LYNDTH00020017) on Town Highway 2, crossing Hawkins Brook, Lyndon, Vermont

Science.gov (United States)

Wild, Emily C.; Medalie, Laura

1997-01-01

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

Mathematical modelling of scour: A review

DEFF Research Database (Denmark)

Sumer, B. Mutlu

2007-01-01

A review is presented of mathematical modelling of scour around hydraulic and marine structures. Principal ideas, general features and procedures are given. The paper is organized in three sections: the first two sections deal with the mathematical modelling of scour around piers....../piles and pipelines, respectively, the two benchmark cases, while the third section deals with the mathematical modelling of scour around other structures such as groins, breakwaters and sea walls. A section is also added to discuss potential future research areas. Over one hundred references are included...

Onset of scour below pipelines and self-burial

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Truelsen, Christoffer; Sichmann, T.

2001-01-01

This paper summarizes the results of an experimental study on the onset of scour below and self-burial of pipelines in currents/waves. Pressure was measured on the surface of a slightly buried pipe at two points, one at the upstream side and the other at the downstream side of the pipe, both...... in the sand bed. The latter enabled the pressure gradient (which drives a seepage flow underneath the pipe) to be calculated. The results indicated that the excessive seepage flow and the resulting piping are the major factor to cause the onset of scour below the pipeline. The onset of scour occurred always...... locally (but not along the length of the pipeline as a two-dimensional process). The critical condition corresponding to the onset of scour was determined both in the case of currents and in the case of waves. Once the scour breaks out, it will propagate along the length of the pipeline, scour holes being...

Measurement and Estimation of Riverbed Scour in a Mountain River

Science.gov (United States)

Song, L. A.; Chan, H. C.; Chen, B. A.

2016-12-01

Mountains are steep with rapid flows in Taiwan. After installing a structure in a mountain river, scour usually occurs around the structure because of the high energy gradient. Excessive scouring has been reported as one of the main causes of failure of river structures. The scouring disaster related to the flood can be reduced if the riverbed variation can be properly evaluated based on the flow conditions. This study measures the riverbed scour by using an improved "float-out device". Scouring and hydrodynamic data were simultaneously collected in the Mei River, Nantou County located in central Taiwan. The semi-empirical models proposed by previous researchers were used to estimate the scour depths based on the measured flow characteristics. The differences between the measured and estimated scour depths were discussed. Attempts were then made to improve the estimating results by developing a semi-empirical model to predict the riverbed scour based on the local field data. It is expected to setup a warning system of river structure safety by using the flow conditions. Keywords: scour, model, float-out device

Level II scour analysis for Bridge 8 (NEWFTH00010008) on Town Highway 1, crossing Wardsboro Brook, Newfane, Vermont

Science.gov (United States)

Wild, Emily C.; Degnan, James

1998-01-01

. 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

Level II scour analysis for Bridge 46 (FFIETH00470046) on Town Highway 47, crossing Black Creek, Fairfield, Vermont

Science.gov (United States)

Wild, Emily C.; Flynn, Robert H.

1998-01-01

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

Level II scour analysis for Bridge 41 (ANDOVT00110041) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont

Science.gov (United States)

Wild, Emily C.; Hammond, Robert E.

1997-01-01

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

Level II scour analysis for Bridge 46 (CHESVT00110046) on Vermont State Route 11, crossing the Middle Branch Williams River, Chester, Vermont

Science.gov (United States)

Wild, Emily C.

1997-01-01

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

Evaluation of abutment scour prediction equations with field data

Science.gov (United States)

Benedict, S.T.; Deshpande, N.; Aziz, N.M.

2007-01-01

The U.S. Geological Survey, in cooperation with FHWA, compared predicted abutment scour depths, computed with selected predictive equations, with field observations collected at 144 bridges in South Carolina and at eight bridges from the National Bridge Scour Database. Predictive equations published in the 4th edition of Evaluating Scour at Bridges (Hydraulic Engineering Circular 18) were used in this comparison, including the original Froehlich, the modified Froehlich, the Sturm, the Maryland, and the HIRE equations. The comparisons showed that most equations tended to provide conservative estimates of scour that at times were excessive (as large as 158 ft). Equations also produced underpredictions of scour, but with less frequency. Although the equations provide an important resource for evaluating abutment scour at bridges, the results of this investigation show the importance of using engineering judgment in conjunction with these equations.

Level II scour analysis for Bridge 25 (ROCHTH00400025) on Town Highway 40, crossing Corporation Brook, Rochester, Vermont

Science.gov (United States)

Wild, Emily C.; Weber, Matthew A.

1998-01-01

.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�

Level II scour analysis for Bridge 13 (LINCTH00010013) on Town Highway 1, crossing Cota Brook, Lincoln, Vermont

Science.gov (United States)

Wild, Emily C.

1998-01-01

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

Edge scour in current adjacent to stone covers

DEFF Research Database (Denmark)

Petersen, Thor Ugelvig; Sumer, B. Mutlu; Meyer, Knud Erik

The present paper reports some early results of an experimental investigation of edge scour in currents. Two kinds of measurements are made (1) Particle Image Velocimetry (PIV) measurements of secondary currents that take place near a junction between the stone cover and the sand bed in a clear......-water experiment; and (2) scour measurements in actual scour experiment in the live-bed regime. The early results indicate that edge scour in a steady current propagating in-line with a stone layer is caused by the combined action of two effects; (1) Primary flow and (2) Secondary flow. The primary flow stirs up...... the sediment and puts into suspension, and the secondary flow carries it away from the junction between the stone layer and the sand bed, resulting in a scour hole forming adjacent to the toe of the stone layer....

Evolution and Reduction of Scour around Offshore Wind Turbines

Science.gov (United States)

McGovern, David; Ilic, Suzana

2010-05-01

Evolution and Reduction of Scour around Offshore Wind Turbines In response to growing socio-economic and environmental demands, electricity generation through offshore wind turbine farms is a fast growing sector of the renewable energy market. Considerable numbers of offshore wind farms exist in the shallow continental shelf seas of the North-West Europe, with many more in the planning stages. Wind energy is harnessed by large rotating blades that drive an electricity generating turbine placed on top of a long cylindrical monopile that are driven into the sea-bed, well into the bed rock below the sediment. Offshore wind turbines are popular due to consistently higher wind speeds and lower visual impact than their onshore counter parts, but their construction and maintenance is not without its difficulties. The alteration of flow by the presence of the wind turbine monopile results in changes in sedimentary processes and morphology at its base. The increase in flow velocity and turbulence causes an amplification of bed shear stress and this can result in the creation of a large scour hole at the monopile base. Such a scour hole can adversely affect the structural integrity and hence longevity of the monopile. Changes to the sea bed caused by this may also locally affect the benthic habitat. We conducted an extensive series of rigid and mobile bed experiments to examine the process of scour under tidal currents. We also test the effectiveness of a flow-altering collared monopile in reducing scour. Firstly, we used Particle Image Velocimetry (PIV) and Acoustic Doppler Velocimetry (ADV) to visualise and analyse the flow and turbulence properties in the local flow around the monopile and collared monopile over a smooth rigid bed under tidal flow. The measured flow, turbulence and shear stress properties are related to mobile bed tests where a Seatek 5 MHz Ultrasonic Ranging system is used to identify the evolution of scour under reversing tidal currents. The tidal

Level II scour analysis for Bridge 15 (BOLTTH00150015) on Town Highway 15, crossing Joiner Brook, Bolton, Vermont

Science.gov (United States)

Burns, Ronda L.; Wild, Emily C.

1998-01-01

mean thalweg depth was observed at the downstream end of the right abutment and along the downstream right wingwall during the Level I assessment. A second scour hole 1.2 ft deeper than the mean thalweg depth was observed at the upstream end of the left abutment and along the upstream left wingwall. The left abutment footing is exposed in the area of the scour hole. 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 at the downstream end of the downstream right wingwall and type-2 stone fill (less than 36 inches diameter) along the downstream left bank. There is also type-3 stone fill (less than 48 inches diameter) 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 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 0.8 to 3.5 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.9 to 15.1 ft. The worst-case abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring

Scour around vertical wall abutment in cohesionless sediment bed

Science.gov (United States)

Pandey, M.; Sharma, P. K.; Ahmad, Z.

2017-12-01

At the time of floods, failure of bridges is the biggest disaster and mainly sub-structure (bridge abutments and piers) are responsible for this failure of bridges. It is very risky if these sub structures are not constructed after proper designing and analysis. Scour is a natural phenomenon in rivers or streams caused by the erosive action of the flowing water on the bed and banks. The abutment undermines due to river-bed erosion and scouring, which generally recognized as the main cause of abutment failure. Most of the previous studies conducted on scour around abutment have concerned with the prediction of the maximum scour depth (Lim, 1994; Melvill, 1992, 1997 and Dey and Barbhuiya, 2005). Dey and Barbhuiya (2005) proposed a relationship for computing maximum scour depth near an abutment, based on laboratory experiments, for computing maximum scour depth around vertical wall abutment, which was confined to their experimental data only. However, this relationship needs to be also verified by the other researchers data in order to support the reliability to the relationship and its wider applicability. In this study, controlled experimentations have been carried out on the scour near a vertical wall abutment. The collected data in this study along with data of the previous investigators have been carried out on the scour near vertical wall abutment. The collected data in this study along with data of the previous have been used to check the validity of the existing equation (Lim, 1994; Melvill, 1992, 1997 and Dey and Barbhuiya, 2005) of maximum scour depth around the vertical wall abutment. A new relationship is proposed to estimate the maximum scour depth around vertical wall abutment, it gives better results all relationships.

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

Science.gov (United States)

Burns, Ronda L.; Wild, Emily C.

1998-01-01

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

Upper bound of abutment scour in laboratory and field data

Science.gov (United States)

Benedict, Stephen

2016-01-01

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a field investigation of abutment scour in South Carolina and used those data to develop envelope curves that define the upper bound of abutment scour. To expand on this previous work, an additional cooperative investigation was initiated to combine the South Carolina data with abutment scour data from other sources and evaluate upper bound patterns with this larger data set. To facilitate this analysis, 446 laboratory and 331 field measurements of abutment scour were compiled into a digital database. This extensive database was used to evaluate the South Carolina abutment scour envelope curves and to develop additional envelope curves that reflected the upper bound of abutment scour depth for the laboratory and field data. The envelope curves provide simple but useful supplementary tools for assessing the potential maximum abutment scour depth in the field setting.

Hall-Effect Sensors for Real-Time Monitoring Pier Scour

Directory of Open Access Journals (Sweden)

Chen-Chia CHEN

2015-01-01

Full Text Available Scour around bridge pier is a major cause of bridge failure such as collapse resulted in loss of life and property. Most of available sensors and approaches for monitoring bridge pier scour are very expensive, which is a main challenge for mass deployment of numerous bridges. Our proposed scour monitoring system utilized low-cost commercial sensors, hall-effect sensors (unit price< $1 that are capable of real-time measuring bridge pier scour with resolution of ~ 2.5 cm, and overall cost for single sensor node of our proposed work is at least 40 % less expensive than existing work. The hall- effect sensor is evaluated under controlled conditions in two laboratory flumes. After scour event, the typical voltage change of the hall-effect sensor is ~ 300 mV, and the system achieve signal-to-noise ratio performance of ~ 60 dB. Finally, we also provide an equation to predict the time variation of scour depth around pier model. Moreover, the master-slave architecture of bridge pier scour monitoring system has scalability and flexibility for mass deployment. This technique has the potential for further widespread implementation in the field.

Level II scour analysis for Bridge 67 (MTHOTH00120067) on Town Highway 12, crossing Freeman Brook, Mount Holly, Vermont

Science.gov (United States)

Wild, Emily C.; Severance, Timothy

1998-01-01

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

Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2012

Science.gov (United States)

Beebee, Robin A.; Schauer, Paul V.

2015-11-19

Streambed scour potential was evaluated at 18 river- and stream-spanning bridges in Alaska that have unknown foundation details or a lack of existing scour analysis. All sites were evaluated for stream stability and long-term scour potential. Contraction scour and abutment scour were calculated for 17 bridges, and pier scour was calculated for 7 bridges that had piers. Vertical contraction (pressure flow) scour was calculated for sites with overtopping floods (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 was also calculated for large recorded floods at several sites. Equations for scour in cohesive soils were used for sites where streambed sediment was silt-sized or smaller.

Evaluation of Maryland abutment scour equation through selected threshold velocity methods

Science.gov (United States)

Benedict, S.T.

2010-01-01

The U.S. Geological Survey, in cooperation with the Maryland State Highway Administration, used field measurements of scour to evaluate the sensitivity of the Maryland abutment scour equation to the critical (or threshold) velocity variable. Four selected methods for estimating threshold velocity were applied to the Maryland abutment scour equation, and the predicted scour to the field measurements were compared. Results indicated that performance of the Maryland abutment scour equation was sensitive to the threshold velocity with some threshold velocity methods producing better estimates of predicted scour than did others. In addition, results indicated that regional stream characteristics can affect the performance of the Maryland abutment scour equation with moderate-gradient streams performing differently from low-gradient streams. On the basis of the findings of the investigation, guidance for selecting threshold velocity methods for application to the Maryland abutment scour equation are provided, and limitations are noted.

Monitoring bridge scour using fiber optic sensors.

Science.gov (United States)

2015-04-01

The scouring process excavates and carries away materials from the bed and banks of streams, and from : around the piers and abutments of bridges. Scour undermines bridges and may cause bridge failures due to : structural instability. In the last 30 ...

Research on Local Scour at Bridge Pier under Tidal Action

Directory of Open Access Journals (Sweden)

Wang Jianping

2015-01-01

Full Text Available Through the local scour test at bridge pier under tidal action in a long time series, this paper observes the growing trend of the deepest point of local scour at bridge pier under tidal conditions with different characteristic parameters, analyzes the impact of repeat sediment erosion and deposition in the scouring pit caused by reversing current on the development process of the scouring pit, and clarifies the relation between the tide and local scouring depth at bridge pier under steady flow conditions, so as to provide a scientific basis for bridge design and safe operation of estuary and harbor areas.

Level II scour analysis for Bridge 63 (MTH0TH00120063) on Town Highway 12, crossing Russell Brook, Mount Holly, Vermont

Science.gov (United States)

Wild, Emily C.; Severance, Timothy

1998-01-01

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

Level II scour analysis for Bridge 44 (LINCTH00330044) on Town Highway 33, crossing the New Haven River, Lincoln, Vermont

Science.gov (United States)

Burns, Ronda L.; Wild, Emily C.

1997-01-01

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

Tsunami Induced Scour Around Monopile Foundations

DEFF Research Database (Denmark)

Fuhrman, David R.; Eltard-Larsen, Bjarke; Baykal, Cüneyt

While the run-up, inundation, and destructive potential of tsunami events has received considerable attention in the literature, the associated interaction with the sea bed i.e. boundary layer dynamics, induced sediment transport, and resultant sea bed morphology, has received relatively little...... specific attention. The present paper aims to further the understanding of tsunami-induced scour, by numerically investigating tsunami-induced flow and scour processes around a monopile structure, representative of those commonly utilized as offshore wind turbine foundations. The simulations are based...... a monopile at model (laboratory) spatial and temporal scales. Therefore, prior to conducting such numerical simulations involving tsunami-induced scour, it is necessary to first establish a methodology for maintaining similarity of model and full field scales. To achieve hydrodynamic similarity we...

A novel bridge scour monitoring and prediction system

Science.gov (United States)

Valyrakis, Manousos; Michalis, Panagiotis; Zhang, Hanqing

2015-04-01

Earth's surface is continuously shaped due to the action of geophysical flows. Erosion due to the flow of water in river systems has been identified as a key problem in preserving ecological health but also a threat to our built environment and critical infrastructure, worldwide. As an example, it has been estimated that a major reason for bridge failure is due to scour. Even though the flow past bridge piers has been investigated both experimentally and numerically, and the mechanisms of scouring are relatively understood, there still lacks a tool that can offer fast and reliable predictions. Most of the existing formulas for prediction of bridge pier scour depth are empirical in nature, based on a limited range of data or for piers of specific shape. In this work, the use of a novel methodology is proposed for the prediction of bridge scour. Specifically, the use of an Adaptive Neuro-Fuzzy Inference System (ANFIS) is proposed to estimate the scour depth around bridge piers. In particular, various complexity architectures are sequentially built, in order to identify the optimal for scour depth predictions, using appropriate training and validation subsets obtained from the USGS database (and pre-processed to remove incomplete records). The model has five variables, namely the effective pier width (b), the approach velocity (v), the approach depth (y), the mean grain diameter (D50) and the skew to flow. Simulations are conducted with data groups (bed material type, pier type and shape) and different number of input variables, to produce reduced complexity and easily interpretable models. Analysis and comparison of the results indicate that the developed ANFIS model has high accuracy and outstanding generalization ability for prediction of scour parameters. The effective pier width (as opposed to skew to flow) is amongst the most relevant input parameters for the estimation. Training of the system to new bridge geometries and flow conditions can be achieved by

Design of the movable limiters for JT-60

International Nuclear Information System (INIS)

Takashima, Tetsuo; Yamamoto, Masahiro; Nakamura, Hiroo; Ohkubo, Minoru; Ohta, Mitsuru

1976-07-01

Two fast-acting movable rail limiters will be used in JT-60 to suppress skin effect of the plasma current with a large radius. They travel safely through a stroke of about 1 m for 0.1 sec in the build-up phase of plasma current. The movable limiter system consists of a driving mechanism, a vacuum seal, a bearing used at high temperatures in a vacuum, a molybdenum rail limiter weighing 200 kg and its auxiliary members. Many problems are involved in construction of the system because the design specifications exceed the present technology. Described are design of the movable limiter system for JT-60 and problems in the mechanical, electrical and vacuum aspects. (auth.)

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

Science.gov (United States)

Wild, Emily C.; Hammond, Robert E.

1997-01-01

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

Multi-Hazard Assessment of Scour Damaged Bridges with UAS-Based Measurements

Science.gov (United States)

Özcan, O.; Ozcan, O.

2017-12-01

Flood and stream induced scour occurring in bridge piers constructed on rivers is one of the mostly observed failure reasons in bridges. Scour induced failure risk in bridges and determination of the alterations in bridge safety under seismic effects has the ultimate importance. Thus, for the determination of bridge safety under the scour effects, the scour amount under bridge piers should be designated realistically and should be tracked and updated continuously. Hereby, the scour induced failures in bridge foundation systems will be prevented and bridge substructure design will be conducted safely. In this study, in order to measure the amount of scour in bridge load bearing system (pile foundations and pile abutments) and to attain very high definition 3 dimensional models of river flood plain for the flood analysis, unmanned aircraft system (UAS) based measurement methods were implemented. UAS based measurement systems provide new and practical approach and bring high precision and reliable solutions considering recent measurement systems. For this purpose, the reinforced concrete (RC) bridge that is located on Antalya Boğaçayı River, Turkey and that failed in 2003 due to flood-induced scour was selected as the case study. The amount of scour occurred in bridge piers and piles was determined realistically and the behavior of bridge piers under scour effects was investigated. Future flood effects and the resultant amount of scour was determined with HEC-RAS software by using digital surface models that were obtained at regular intervals using UAS for the riverbed. In the light of the attained scour measurements and expected scour after a probable flood event, the behavior of scour damaged RC bridge was investigated by pushover and time history analyses under lateral and vertical seismic loadings. In the analyses, the load and displacement capacity of bridge was observed to diminish significantly under expected scour. Thus, the deterioration in multi hazard

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

Science.gov (United States)

Wild, Emily C.

1998-01-01

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

Investigation of pier scour in coarse-bed streams in Montana, 2001 through 2007

Science.gov (United States)

Holnbeck, Stephen R.

2011-01-01

A primary goal of ongoing field research of bridge scour is improvement of scour-prediction equations so that pier-scour depth is predicted accurately-an important element of hydraulic analysis and design of highway bridges that cross streams, rivers, and other waterways. Scour depth for piers in streambeds with a mixture of sand, gravel, cobbles, and boulders (coarse-bed streams, which are common in Montana) generally is less than the scour depth in finer-grained (sandy) streambeds under similar conditions. That difference is attributed to an armor layer of coarser material. Pier-scour data from the U.S. Geological Survey were used in this study to develop a bed-material correction factor, which was incorporated into the Federal Highway Administration's recommended equation for computing pier scour. This report describes results of a study of pier scour in coarse-bed streams at 59 bridge sites during 2001-2007 in the mountain and foothill regions of western Montana. Respective drainage areas ranged from about 3 square miles (mi2) to almost 20,000 mi2. Data collected and analyzed for this study included 103 pier-scour measurements; the report further describes data collection, shows expansion of the national coarse pier-scour database, discusses use of the new data in evaluation of relative accuracy of various predictive equations, and demonstrates how differences in size and gradation between surface bed material and shallow-subsurface bed material might relate to pier scour. Nearly all measurements were made under clear-water conditions with no incoming sediment supply to the bridge opening. Half of the measurements showed approach velocities that equaled or surpassed the critical velocity for incipient motion of bed material, possibly indicating that measurements were made very near the threshold between clear-water and live-bed scour, where maximum scour was shown in laboratory studies. Data collected in this study were compared to selected pier-scour data from

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

Science.gov (United States)

Wild, Emily C.

1998-01-01

.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

Level II scour analysis for Bridge 30 (NEWHTH00050030) on Town Highway 5, crossing the New Haven River, New Haven, Vermont

Science.gov (United States)

Burns, Ronda L.; Wild, Emily C.

1998-01-01

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

Level II scour analysis for Bridge 7H (HUNTTH0001007H) on Town Highway 1, crossing Cobb Brook, Huntington, Vermont

Science.gov (United States)

Wild, Emily C.

1997-01-01

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

Level II scour analysis for Bridge 34 (WWINTH00370034) on Town Highway 37, crossing Mill Brook, West Windsor, Vermont

Science.gov (United States)

Boehmler, Erick M.; Wild, Emily C.

1998-01-01

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

Wall-Roughness Effects on Flow and Scouring in Curved Channels with Gravel Beds

OpenAIRE

Hersberger, D.; Franca, Mário J.; Schleiss, Anton

2016-01-01

Due to a complex three-dimensional flow pattern, the outer banks of river bends are predisposed to erosion. When endangering civil structures, preventing measures to mitigate this erosion are thus required. Vertical ribs at protection walls for scour reduction have been applied to several flood protection projects in mountain rivers; nevertheless, no systematic and intensive study has been presented so far to evaluate their effect. This paper investigates experimentally the effect of vertical...

Concept Design of Movable Beam of Hydraulic Press

Directory of Open Access Journals (Sweden)

Li Yancong

2017-01-01

Full Text Available The hydraulic press movable beam is one of the key components of the hydraulic press; its design quality impacts the accuracy of the workpiece that the press suppressed. In this paper, first, with maximum deflection and material strength as constraints, mechanical model of the movable beam is established; next, the concept design model of the moveable beam structure is established; the relationship among the force of the side cylinder, the thickness of the inclined plate, outer plate is established also. Taking movable beam of the 100MN type THP10-10000 isothermal forging hydraulic press as an example, the conceptual design result is given. This concept design method mentoned in the paper has general meaning and can apply to other similar product design.

Bridge pressure flow scour for clear water conditions

Science.gov (United States)

2009-10-01

The equilibrium scour at a bridge caused by pressure flow with critical approach velocity in clear-water simulation conditions was studied both analytically and experimentally. The flume experiments revealed that (1) the measured equilibrium scour pr...

Level II scour analysis for Bridge 52 (CHESTH00100052) on Town Highway 10, crossing the South branch Williams River, Chester, Vermont

Science.gov (United States)

Wild, Emily C.; Ivanoff, Michael A.

1998-01-01

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

Multi-approach analysis of maximum riverbed scour depth above subway tunnel

Directory of Open Access Journals (Sweden)

Jun Chen

2010-12-01

Full Text Available When subway tunnels are routed underneath rivers, riverbed scour may expose the structure, with potentially severe consequences. Thus, it is important to identify the maximum scour depth to ensure that the designed buried depth is adequate. There are a range of methods that may be applied to this problem, including the fluvial process analysis method, geological structure analysis method, scour formula method, scour model experiment method, and numerical simulation method. However, the application ranges and forecasting precision of these methods vary considerably. In order to quantitatively analyze the characteristics of the different methods, a subway tunnel passing underneath a river was selected, and the aforementioned five methods were used to forecast the maximum scour depth. The fluvial process analysis method was used to characterize the river regime and evolution trend, which were the baseline for examination of the scour depth of the riverbed. The results obtained from the scour model experiment and the numerical simulation methods are reliable; these two methods are suitable for application to tunnel projects passing underneath rivers. The scour formula method was less accurate than the scour model experiment method; it is suitable for application to lower risk projects such as pipelines. The results of the geological structure analysis had low precision; the method is suitable for use as a secondary method to assist other research methods. To forecast the maximum scour depth of the riverbed above the subway tunnel, a combination of methods is suggested, and the appropriate analysis method should be chosen with respect to the local conditions.

The Reverse Approach for Monopile Scour

DEFF Research Database (Denmark)

Hartvig, Peres Akrawi

2012-01-01

The present paper deals with the theoretical and numerical modeling of scouring and backfilling around an offshore monopile. Based on existing relations for the bed load and the bed update, and a new model for the sediment pickup, it demonstrates the possibility of computing the mean bed shear...... stress if the bed and bed update is estimated. The present concepts may be useful for developing methods for scour forecasting....

Scour process caused by multiple subvertical non-crossing jets

Directory of Open Access Journals (Sweden)

Stefano Pagliara

2017-01-01

Full Text Available The scour process induced by plunging jets is an important topic for hydraulic engineers. In recent decades, several researchers have developed new strategies and methodologies to control the scour morphology, including different jet arrangements and structures located in the stilling basin. It has been found that multiple jets can cause less scouring than single plunging jets. Based on this evidence, this study aimed to investigate the equilibrium morphology caused by multiple non-crossing jets. A dedicated laboratory model was built and experimental tests were carried out under different combinations of jet inclination angles, by varying the tailwater level and the virtual crossing point location, which was set below the original channel bed level. It was experimentally shown that the equilibrium scour morphology depends on the jet discharge, the differences in non-crossing jet inclination angles, the downstream water level, and the distance of the virtual crossing point from the original channel bed level. In particular, the last parameter was found to be one of the most influential parameters, because of the resulting flow patterns inside the water body. Furthermore, the analysis of experimental evidence allowed for a complete and detailed classification of the scour hole typologies. Three different scour typologies were distinguished and classified. Finally, based on previous studies, two novel relationships have been proposed to predict both the maximum scour depth and length within a large range of hydraulic and geometric parameters.

Design and evaluation of a high sensitivity spiral TDR scour sensor

Science.gov (United States)

Gao, Quan; (Bill Yu, Xiong

2015-08-01

Bridge scour accounts for more than half of the reported bridge failures in the United States. Scour monitoring technology based on time domain reflectometry (TDR) features the advantages of being automatic and inexpensive. The senior author’s team has developed a few generations of a TDR bridge scour monitoring system, which have succeeded in both laboratory and field evaluations. In this study, an innovative spiral TDR sensor is proposed to further improve the sensitivity of the TDR sensor in scour detection. The spiral TDR sensor is made of a parallel copper wire waveguide wrapped around a mounting rod. By using a spiral path for the waveguide, the TDR sensor achieves higher sensitivity than the traditional straight TDR probes due to longer travel distance of the electromagnetic (EM) wave per unit length in the spiral probe versus traditional probe. The performance of the new TDR spiral scour sensor is validated by calibration with liquids with known dielectric constant and wet soils. Laboratory simulated scour-refilling experiments are performed to evaluate the performance of the new spiral probe in detecting the sediment-water interface and therefore the scour-refill process. The tests results indicate that scour depth variation of less than 2 cm can be easily detected by this new spiral sensor. A theory is developed based on the dielectric mixing model to simplify the TDR signal analyses for scour depth detection. The sediment layer thickness (directly related to scour depth) varies linearly with the square root of the bulk dielectric constant of the water-sediment mixture measured by the spiral TDR probe, which matches the results of theoretical prediction. The estimated sediment layer thickness and therefore scour depth from the spiral TDR sensor agrees very well with that by direct physical measurement. The spiral TDR sensor is four times more sensitive than a traditional straight TDR probe.

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

Science.gov (United States)

Olson, Scott A.

1997-01-01

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

Movable collimator for positron annihilation imaging device

International Nuclear Information System (INIS)

Thompson, C.J.

1981-01-01

A positron annihilation imaging device having two circular arrays of detectors disposed in spaced apart parallel planes wherein axially movable annular collimator rings are generally disposed in a pair of opposite planes outside the associated planes of the collimators to each collimator being movable toward the opposite collimator and a central collimator of annular configuration generally disposed between the two rows of detectors but being split into two rings which may be separated, the outer and inner collimators serving to enhance data readout and imaging

An Accelerometer-Based Sensor System for Real-Time Bridge Scour Monitoring

Directory of Open Access Journals (Sweden)

Yi-Jie Hsieh

2015-11-01

Full Text Available With the fast global climate change, many bridge structures are facing the nature disasters such as earthquakes and floods. The damage of bridges can cause the severe cost of human life and property. The heavy rain brought by the typhoon in July and August in Taiwan causes the bridge scour and makes the damage or collapse for bridges. Since scour is one of the major causes for bridge failure, how to monitor the bridge scour becomes an important task in Taiwan. This paper presents a real-time bridge scour monitoring system based on accelerometer sensors. The presented sensor network consists of a gateway node and under-water sensor nodes with the wired RS-485 communication protocol. The proposed master-slave architecture of the bridge scour monitoring system owns the scalability and flexibility and is setup in the field currently. The experimental results in the field show the presented sensor system can detect the bridge scour effectively with our proposed scour detection algorithm in real time.

Level II scour analysis for Bridge 37 (DUXBTH00120037) on Town Highway 12, crossing Ridley Brook, Duxbury, Vermont

Science.gov (United States)

Wild, Emily C.; Ivanhoff, Michael A.

1997-01-01

, 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.

Multi-approach analysis of maximum riverbed scour depth above subway tunnel

OpenAIRE

Jun Chen; Hong-wu Tang; Zui-sen Li; Wen-hong Dai

2010-01-01

When subway tunnels are routed underneath rivers, riverbed scour may expose the structure, with potentially severe consequences. Thus, it is important to identify the maximum scour depth to ensure that the designed buried depth is adequate. There are a range of methods that may be applied to this problem, including the fluvial process analysis method, geological structure analysis method, scour formula method, scour model experiment method, and numerical simulation method. However, the applic...

Evaluation of streambed scour at bridges over tidal waterways in Alaska

Science.gov (United States)

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

Scour at Vertical Piles in Sand-Clay Mixtures under Waves

DEFF Research Database (Denmark)

Dey, Subhasish; Helkjær, Anders; Sumer, B. Mutlu

2011-01-01

Marine sediments often contain sand-clay mixtures in widely varying proportions. This study presents the results of equilibrium scour and time variation of scour depths at circular piles embedded vertically in clay alone and sand-clay mixed beds under waves. Experiments were conducted in a wave...... flume with different proportions of sand-clay mixtures as bed sediments. Test results for the cases of steady current and sand alone under waves are used as references. The equilibrium scour depth reduces with an increase in clay proportion n (by weight) in a sand-clay mixture. Interestingly, the scour...

Level II scour analysis for Bridge 13 (SHARTH00040013) on Town Highway 4, crossing Broad Brook, Sharon, Vermont

Science.gov (United States)

Wild, Emily C.; Weber, Matthew A.

1997-01-01

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.

Simulation of Wave-Plus-Current Scour beneath Submarine Pipelines

DEFF Research Database (Denmark)

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

2016-01-01

A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed and suspen......A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed...... and suspended load descriptions forming the basis for seabed morphology. The model was successfully validated against experimental measurements involving scour development and eventual equilibrium in pure-current flows over a range of Shields parameters characteristic of both clear-water and live-bed regimes....... This validation complements previously demonstrated accuracy for the same model in simulating pipeline scour processes in pure-wave environments. The model was subsequently utilized to simulate combined wave-plus-current scour over a wide range of combined Keulegan–Carpenter numbers and relative current strengths...

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

Science.gov (United States)

Ivanoff, Michael A.; Wild, Emily C.

1998-01-01

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

Research on the Effects of the Movable Die and its Counter Force on Sheet Hydroforming

International Nuclear Information System (INIS)

Zhou, Li X.; Zhang, Shi H.; Wang, Ben X.

2007-01-01

An improved Sheet Hydro-forming process was proposed, which was investigated in Institute of Metal Research, Chinese Academy of Sciences. ASAME system and FEM are used to analyze the forming process to explain some results that were found in the experiment. In the simulation, the effect of the movable die on the maximum principal stress is investigated in detail by using the FEM code LS-DYNA. For this case, the movable die changes the distribution of the maximum principal stress. For the sheet hydroforming without the movable die, the principal stress near the shoulder of the movable die arrives to the maximum value when t=0.0033s suddenly. But for the sheet hydroforming with the movable die, the maximum principal stress still lies in the die radius. The principal stress near the shoulder of the movable die is smaller. At the last stage contacting with the die, for the case without the movable die, the maximum principal stress near the shoulder of movable die is larger than that of the sheet hydroforming with the movable die. Moreover, the stress distribution near the shoulder of movable die for the case without the movable die is complicated. It is instable and very easy to occur wrinkling. The movable die delays the maximum thickness strain to the contacting die stage. So the formability of sheet metal can be remarkably improved by adopting the movable die. On a certain extent, the uniform distribution of thickness can be realized by increasing the counterforce of movable die. The minimum thickness reduction moves outside which is very helpful for the uniform thickness distribution. In this paper, two kinds of materials, soft steel and stainless steel, were investigated

Study of the time-dependent clear water scour around circular bridge piers

Directory of Open Access Journals (Sweden)

Aksoy Aysegul Ozgenc

2017-03-01

Full Text Available The local scour around bridge piers influences their stabilities and plays a key role in the bridge failures. The estimation of the maximum possible scour depth around bridge piers is an important step in the design of the bridge pier foundations. In this study, the temporal evolution of local scour depths as well as the equilibrium scour depths were analyzed.

3D mathematical modelling of scour around a circular pile in current

DEFF Research Database (Denmark)

Roulund, Andreas; Sumer, B. Mutlu; Fredsøe, Jørgen

1999-01-01

This paper deals with scour around a circular pile exposed to a steady current. A 3D numerical model incorporated with the k-w,SST closure coupled with the sediment-continuity equation and a bedload sediment transport formula has been used to predict the scour. 3D calculations have also been...... carried out for a plane rigid bottom for reference purpose. The predicted flow features are apparently in fairly good agreement with the experimental data. Early calculations indicate that the model is able to predict the scour properties satisfactorily in the initial stages of the scour process, up...... to scour depth of 0.6-0.7 times the pile diameter. Calculations that describe the entire scour process (including the equilibrium stage) are underway....

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

Science.gov (United States)

Wild, Emily C.

1997-01-01

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.

Management of excessive movable tissue: a modified impression technique.

Science.gov (United States)

Shum, Michael H C; Pow, Edmond H N

2014-08-01

Excessive movable tissue is a challenge in complete denture prosthetics. A modified impression technique is presented with polyvinyl siloxane impression material and a custom tray with relief areas and perforations in the area of the excessive movable tissue. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Extreme Changes in Stream Geomorphic Conditions induced by Fluvial Scour in Bridges

Science.gov (United States)

Özcan, O.; Ozcan, O.

2016-12-01

The numerous complexities associated with bridge scour have caused scour to be one of the most active topics of stream geomorphic research. The assessment of local scouring mechanism around bridge piers provides information for decision-making regarding the pile footing design, predicting the safety of bridges under critical scoured conditions, and as a result, may help prevent unnecessary loses. In the study, bridge design plans and HEC-RAS modeling were used for the assessment of changes in stream geomorphic conditions. The derived fluvial scour depths were compared with the field measurements and the empirical formula which is based on stream flow discharge rate, streambed condition and shape of river. Preliminary results revealed that bridge damage resulting from the flood event in 2003 induced substantial scour around bridge piles. Afterwards, significant stream bed change was observed under the influence of fluvial scour in another flood occurred in 2009. Consequently, geomorphic conditions of the stream bed should be considered in the structural design of the bridges.

Experimental Evaluation of Backfill in Scour Holes Around Offshore Monopiles

DEFF Research Database (Denmark)

Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Frigaard, Peter

2010-01-01

be to allow the forming of a scour hole and hereby design the monopile with a larger penetration depth. The depth of the scour hole will change over time as the scour depth will increasewhen currents are dominating and backfilling of the scour hole will take placewhenwaves are dominating. Several researchers...... of the foundation for fatigue. A backfill test has been performed in the LargeWave Channel (GWK) of the Coastal Research Centre (FZK) in Hannover.The relative density of the backfilled soil material has based on soil samples and CPT measurements been determined to be in the range of 60–80%. The normalized time...

Level II scour analysis for Bridge 36 (DUXBTH00040036) on Town Highway 4, crossing Crossett Brook, Duxbury, Vermont

Science.gov (United States)

Wild, Emily C.; Degnan, James R.

1997-01-01

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.

Level II scour analysis for Bridge 51 (JERITH00590051) on Town Highway 59, crossing The Creek, Jericho, Vermont

Science.gov (United States)

Wild, Emily C.

1998-01-01

(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.

Evaluation of scour potential of cohesive soils - phase 2.

Science.gov (United States)

2015-01-01

Determination of erosion parameters in order to predict scour depth is imperative to designing safe, : economic, and efficient bridge foundations. Scour behavior of granular soils is generally understood, : and design criteria have been established b...

Flow and scour around spherical bodies

DEFF Research Database (Denmark)

Truelsen, Christoffer

2003-01-01

Spherical bodies placed in the marine environment may bury themselves due to the action of the waves and the current on the sediment in their immediate neighborhood. The present study addresses this topic by a numerical and an experimental investigation of the flow and scour around a spherical body...... results except in the critical flow regime. For flow around a near-wall sphere, a weak horseshoe vortex emerges as the gap ratio becomes less than or equal to 0.3. In Chapter 3, a RANS flow solver has been used to compute the bed shear stress for a near-wall sphere. The model results compare well...... 4, an experimental study on the scour around spherical bodies and self-burial in sand for steady current and waves has been carried out. The effect of the contraction of streamlines is found to be the key element in the scour process both for steady current and waves. Furthermore, it is demonstrated...

U.S. Geological Survey - Virginia Department of Transportation: Bridge scour pilot study

Science.gov (United States)

Austin, Samuel H.

2018-02-27

BackgroundCost effective and safe highway bridge designs are required to ensure the long-term sustainability of Virginia’s road systems. The streamflows that, over time, scour streambed sediments from bridge piers inherently affect bridge safety and design costs. To ensure safety, bridge design must anticipate streambed scour at bridge piers over the lifespan of a bridge. Until recently Federal Highway Administration (FHWA) guidance provided only for scour estimates of granular, noncohesive, highly erosive material yielding overestimates of scour potential in instances when streambed materials offer some resistance to scour. This study seeks to estimate stream power and streambed scour for these more resistive sites, with bridge piers potentially established in cohesive soil or erodible rock. This new knowledge may provide significant construction cost savings while ensuring design and construction of safe highway bridges.

EFFECT OF BRIDGE PIERS INCLINATION AND ROUGHNESS ON SCOUR PIT DIMENSIONS

Directory of Open Access Journals (Sweden)

Moaed S. Khalil

2013-05-01

Full Text Available In this paper a laboratory work was performed to study the effect of bridge piers inclination and surface roughness on scour pit dimensions. Fifty four experiments were conducted using three different sizes and inclinations Pier models fixed in a sandy bed channel. First, the axis of the pier was parallel to the flow, then it was inclined by 30° and finally by 45°. Each model was tested under three different flow discharges for a period not less than two hours and at the end of each experiment the dimensions of the scour pit were measured. The same experiments were repeated after roughening the surface of each pier by fine gravel of 2mm in diameter to increase its roughness.The results of the experiment showed a clear reduction in scour pit dimensions after increasing pier roughness, the percentage of decreases in scour depth was between 2 % and 61%, while the scour length decreased between 2.5% and 22%, and finally the width of scour decreases was between 3% and 19.7%. The results also showed that the inclination of pier's axis produced an increase in scour pit dimensions. Finally, the empirical relationships of the results showed that it's possible to explain the relation between the flow discharge and each of scour pit dimensions by a simple linear equation, where the determination coefficient were more than 0.94 for all relations. 

Positron annihilation imaging device having movable collimator

International Nuclear Information System (INIS)

Thompson, C.J.

1981-01-01

This patent application relates to a positron annihilation imaging device comprising two circular arrays of detectors disposed in spaced apart parallel planes and circumferentially offset by half the detector spacing, axially movable annular outer collimator rings, generally disposed in a pair of opposite planes outside the associated planes of the detectors, each collimator being movable toward the opposite collimator. An inner collimator of annular configuration is disposed between the two rows of detectors and is formed in two rings which may be separated axially. The outer and inner collimators serve to enhance data readout and imaging. (author)

Level II scour analysis for Bridge 8 (ANDOTH00010008) on Town Highway 1, crossing Andover Branch, Andover, Vermont

Science.gov (United States)

Flynn, Robert H.; Wild, Emily C.

1997-01-01

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.

Vulnerability of bridges to scour: insights from an international expert elicitation workshop

Science.gov (United States)

Lamb, Rob; Aspinall, Willy; Odbert, Henry; Wagener, Thorsten

2017-08-01

Scour (localised erosion) during flood events is one of the most significant threats to bridges over rivers and estuaries, and has been the cause of numerous bridge failures, with damaging consequences. Mitigation of the risk of bridges being damaged by scour is therefore important to many infrastructure owners, and is supported by industry guidance. Even after mitigation, some residual risk remains, though its extent is difficult to quantify because of the uncertainties inherent in the prediction of scour and the assessment of the scour risk. This paper summarises findings from an international expert workshop on bridge scour risk assessment that explores uncertainties about the vulnerability of bridges to scour. Two specialised structured elicitation methods were applied to explore the factors that experts in the field consider important when assessing scour risk and to derive pooled expert judgements of bridge failure probabilities that are conditional on a range of assumed scenarios describing flood event severity, bridge and watercourse types and risk mitigation protocols. The experts' judgements broadly align with industry good practice, but indicate significant uncertainty about quantitative estimates of bridge failure probabilities, reflecting the difficulty in assessing the residual risk of failure. The data and findings presented here could provide a useful context for the development of generic scour fragility models and their associated uncertainties.

Updating HEC-18 pier scour equations for noncohesive soils.

Science.gov (United States)

2016-10-01

A dataset of 594 bridge pier scour observations from two laboratory and three field studies was compiled. The dataset served as the testing ground for evaluating potential enhancements to the pier scour tools for noncohesive soils in Hydraulic Engine...

Bleaching of hydroentangled greige cotton nonwoven fabrics without scouring

Science.gov (United States)

This work investigated whether a hydroentangled greige cotton nonwoven fabric made at a relatively high hydroentangling water pressure, say, 135-bar, could be successfully bleached to attain the desired whiteness, absorbency and other properties without traditional scouring. Accordingly, the scoured...

Movable limiter experiment on TPE-1RM15 reversed field pinch machine

International Nuclear Information System (INIS)

Yagi, Yasuyuki; Shimada, Toshio; Hirota, Isao; Maejima, Yoshiki; Hirano, Yoichi; Ogawa, Kiyoshi

1989-01-01

Two movable limiters with a graphite head (35 mm Φ x 40 mm high) were installed in TPE-1RM15 reversed field pinch (RFP) machine. Measurement of the heat flux input to the movable limiters and the effect of the insertion of the limiter on plasma properties, as well as surface analyses of the graphite head after the exposure, were conducted. The heat flux input into the electron drift side of the limiter exceeded that from the ion drift side by factor of 4-6 at the maximum insertion of the limiters (10 mm inward from the shadow of the fixed limiters). This factor increased as the movable limiter protruded into the plasma, and this profile is attributed to the change of the pitch profile of the magnetic field line at the plasma periphery. At the maximum insertion of the two movable limiters, the energy input into a graphite head was about 10% of the joule input energy during the current sustainment phase. The one turn loop voltage and plasma resistance increased when the movable limiters were inserted beyond the shadow of the fixed limiters, and the increment of the joule input power roughly correlates with the increment of the loss power into the protruded movable limiters. Unbalanced position scanning showed that the relative distance of a movable limiter from the plasma column was not affected by another movable limiter installed 180 0 toroidally away from the former limiter. Fundamental surface analyses of the graphite head showed that deposition of metal impurities (Fe and Cr) was higher at the corner of the ion drift side than that of the electron shift side, and that the corner of the electron drift side was more roughened than the ion drift side. (orig.)

Level II scour analysis for Bridge 34 (ROCHTH00210034) on Town Highway 21, crossing the White River, Rochester, Vermont

Science.gov (United States)

Wild, Emily C.; Degnan, James

1997-01-01

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.

Vulnerability of bridges to scour: insights from an international expert elicitation workshop

Directory of Open Access Journals (Sweden)

R. Lamb

2017-08-01

Full Text Available Scour (localised erosion during flood events is one of the most significant threats to bridges over rivers and estuaries, and has been the cause of numerous bridge failures, with damaging consequences. Mitigation of the risk of bridges being damaged by scour is therefore important to many infrastructure owners, and is supported by industry guidance. Even after mitigation, some residual risk remains, though its extent is difficult to quantify because of the uncertainties inherent in the prediction of scour and the assessment of the scour risk. This paper summarises findings from an international expert workshop on bridge scour risk assessment that explores uncertainties about the vulnerability of bridges to scour. Two specialised structured elicitation methods were applied to explore the factors that experts in the field consider important when assessing scour risk and to derive pooled expert judgements of bridge failure probabilities that are conditional on a range of assumed scenarios describing flood event severity, bridge and watercourse types and risk mitigation protocols. The experts' judgements broadly align with industry good practice, but indicate significant uncertainty about quantitative estimates of bridge failure probabilities, reflecting the difficulty in assessing the residual risk of failure. The data and findings presented here could provide a useful context for the development of generic scour fragility models and their associated uncertainties.

The design and application of the movable limiter in EAST

Energy Technology Data Exchange (ETDEWEB)

Lei Cao, E-mail: caolei@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Science, Shushanhu road 350, Hefei 230031 (China); Song Yuntao [Institute of Plasma Physics, Chinese Academy of Science, Shushanhu road 350, Hefei 230031 (China)

2011-10-15

There are two movable limiters that have been installed on EAST. The movable limiter consists of three parts that are blade, support components and drive components. The blade which consists of heat sink and graphite tiles has to face plasma during plasma discharge. The support components consist of a long shaft and a movable plate. The drive components consists of a screw shaft, a step motor, four guide shafts and two support plates. There is an extra support which has fit in Tokamak and a frame on the outside of the flange. The specific shape of the blade has been optimized so that the graphite tiles on the blade can withstand max 5 MW/m{sup 2} heat load with two long cooling channels. The long shaft of the transfer components connect with blade to make it can move along the axis of the limiter. The movable blade could adjust a wide variety of plasma major and minor diameters. The drive components provide motion from step motor which can be remote controlled in the control room far away from the scene. The rotation is translated to slide motion by a screw shaft. The screw shaft can push the slide which connected with the long shaft to at last move the blade. To introduce the motion from outside to the vacuum vessel, the limiter has a long bellow and special structure as dynamical seal. This seal structure proved very reliable. The remote control system has been also equipped the distance sensor to provide the information of the position of the limiter. The control system is based on PC so it can be easily operated. The two movable limiters have been installed on the EAST. During past twice discharges, the movable limiter proved to be a useful tool for EAST to control the plasma boundary.

The design and application of the movable limiter in EAST

International Nuclear Information System (INIS)

Lei Cao; Song Yuntao

2011-01-01

There are two movable limiters that have been installed on EAST. The movable limiter consists of three parts that are blade, support components and drive components. The blade which consists of heat sink and graphite tiles has to face plasma during plasma discharge. The support components consist of a long shaft and a movable plate. The drive components consists of a screw shaft, a step motor, four guide shafts and two support plates. There is an extra support which has fit in Tokamak and a frame on the outside of the flange. The specific shape of the blade has been optimized so that the graphite tiles on the blade can withstand max 5 MW/m 2 heat load with two long cooling channels. The long shaft of the transfer components connect with blade to make it can move along the axis of the limiter. The movable blade could adjust a wide variety of plasma major and minor diameters. The drive components provide motion from step motor which can be remote controlled in the control room far away from the scene. The rotation is translated to slide motion by a screw shaft. The screw shaft can push the slide which connected with the long shaft to at last move the blade. To introduce the motion from outside to the vacuum vessel, the limiter has a long bellow and special structure as dynamical seal. This seal structure proved very reliable. The remote control system has been also equipped the distance sensor to provide the information of the position of the limiter. The control system is based on PC so it can be easily operated. The two movable limiters have been installed on the EAST. During past twice discharges, the movable limiter proved to be a useful tool for EAST to control the plasma boundary.

Level II scour analysis for Bridge 29 (DORSTH00100029) on Town Highway 10, crossing the Mettawee River, Dorset, Vermont

Science.gov (United States)

Wild, Emily C.

1997-01-01

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.

Gene expression programming for prediction of scour depth downstream of sills

Science.gov (United States)

Azamathulla, H. Md.

2012-08-01

SummaryLocal scour is crucial in the degradation of river bed and the stability of grade control structures, stilling basins, aprons, ski-jump bucket spillways, bed sills, weirs, check dams, etc. This short communication presents gene-expression programming (GEP), which is an extension to genetic programming (GP), as an alternative approach to predict scour depth downstream of sills. Published data were compiled from the literature for the scour depth downstream of sills. The proposed GEP approach gives satisfactory results (R2 = 0.967 and RMSE = 0.088) compared to the existing predictors (Chinnarasri and Kositgittiwong, 2008) with R2 = 0.87 and RMSE = 2.452 for relative scour depth.

Prediction of scour below submerged pipeline crossing a river using ANN.

Science.gov (United States)

Azamathulla, H M; Zakaria, Nor Azazi

2011-01-01

The process involved in the local scour below pipelines is so complex that it makes it difficult to establish a general empirical model to provide accurate estimation for scour. This paper describes the use of artificial neural networks (ANN) to estimate the pipeline scour depth. The data sets of laboratory measurements were collected from published works and used to train the network or evolve the program. The developed networks were validated by using the observations that were not involved in training. The performance of ANN was found to be more effective when compared with the results of regression equations in predicting the scour depth around pipelines.

Equilibrium depth of scour at straight guide banks

Science.gov (United States)

Gjunsburgs, B.; Bulankina, V.

2017-10-01

The equilibrium stage of scour at the head of straight guide banks with a uniform and stratified bed conditions have been studied. The contraction of the river by bridge crossing with straight guide banks considerably alters the flow pattern. The streamlines become curve and the concentration of streamlines, longitudinal and transverse slopes of the water surface, a local increase in velocity, vortex and eddy structures, and the origin of a flow separation zone between the extreme streamlines and the guide bank are observed and local scour is developing at the head of the straight guide banks. New formulae for calculation of equilibrium depth of scour at straight guide banks at uniform and stratified river bed is elaborated and confirmed by tests and computer modelling results.

Level II scour analysis for Bridge 32 (TUNBTH00600032) on Town Highway 60, crossing First Branch White River, Tunbridge, Vermont

Science.gov (United States)

Wild, Emily C.

1998-01-01

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.

Monitoring bridge scour using fiber optic sensors : [tech summary].

Science.gov (United States)

2015-04-01

It is well known that scour is one of the major causes of bridge failures. In the last 30 years, more than 1,000 bridges collapsed in : the US and about 60% of the failures are related to the scour of bridges foundations. Due to the difficulty in ...

The upper bound of abutment scour defined by selected laboratory and field data

Science.gov (United States)

Benedict, Stephen; Caldwell, Andral W.

2015-01-01

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a field investigation of abutment scour in South Carolina and used that data to develop envelope curves defining the upper bound of abutment scour. To expand upon this previous work, an additional cooperative investigation was initiated to combine the South Carolina data with abutment-scour data from other sources and evaluate the upper bound of abutment scour with the larger data set. To facilitate this analysis, a literature review was made to identify potential sources of published abutment-scour data, and selected data, consisting of 446 laboratory and 331 field measurements, were compiled for the analysis. These data encompassed a wide range of laboratory and field conditions and represent field data from 6 states within the United States. The data set was used to evaluate the South Carolina abutment-scour envelope curves. Additionally, the data were used to evaluate a dimensionless abutment-scour envelope curve developed by Melville (1992), highlighting the distinct difference in the upper bound for laboratory and field data. The envelope curves evaluated in this investigation provide simple but useful tools for assessing the potential maximum abutment-scour depth in the field setting.

Predictive model for local scour downstream of hydrokinetic turbines in erodible channels

Science.gov (United States)

Musa, Mirko; Heisel, Michael; Guala, Michele

2018-02-01

A modeling framework is derived to predict the scour induced by marine hydrokinetic turbines installed on fluvial or tidal erodible bed surfaces. Following recent advances in bridge scour formulation, the phenomenological theory of turbulence is applied to describe the flow structures that dictate the equilibrium scour depth condition at the turbine base. Using scaling arguments, we link the turbine operating conditions to the flow structures and scour depth through the drag force exerted by the device on the flow. The resulting theoretical model predicts scour depth using dimensionless parameters and considers two potential scenarios depending on the proximity of the turbine rotor to the erodible bed. The model is validated at the laboratory scale with experimental data comprising the two sediment mobility regimes (clear water and live bed), different turbine configurations, hydraulic settings, bed material compositions, and migrating bedform types. The present work provides future developers of flow energy conversion technologies with a physics-based predictive formula for local scour depth beneficial to feasibility studies and anchoring system design. A potential prototype-scale deployment in a large sandy river is also considered with our model to quantify how the expected scour depth varies as a function of the flow discharge and rotor diameter.

Numerical simulation of wave-induced scour and backfilling processes beneath submarine pipelines

DEFF Research Database (Denmark)

Fuhrman, David R.; Baykal, Cüneyt; Sumer, B. Mutlu

2014-01-01

A fully-coupled hydrodynamic/morphodynamic numerical model is presented and utilized for the simulation of wave-induced scour and backfilling processes beneath submarine pipelines. The model is based on solutions to Reynolds-averaged Navier–Stokes equations, coupled with k−ω turbulence closure......≤30 demonstrate reasonable match with previous experiments, both in terms of the equilibrium scour depth as well as the scour time scale. Wave-induced backfilling processes are additionally studied by subjecting initial conditions taken from scour simulations with larger KC to new wave climates...... characterized by lower KC values. The simulations considered demonstrate the ability of the model to predict backfilling toward expected equilibrium scour depths based on the new wave climate, in line with experimental expectations. The simulated backfilling process is characterized by two stages: (1...

Evaluation of bridge instability caused by dynamic scour based on fractal theory

International Nuclear Information System (INIS)

Lin, Tzu-Kang; Shian Chang, Yu; Wu, Rih-Teng; Chang, Kuo-Chun

2013-01-01

Given their special structural characteristics, bridges are prone to suffer from the effects of many hazards, such as earthquakes, wind, or floods. As most of the recent unexpected damage and destruction of bridges has been caused by hydraulic issues, monitoring the scour depth of bridges has become an important topic. Currently, approaches to scour monitoring mainly focus on either installing sensors on the substructure of a bridge or identifying the physical parameters of a bridge, which commonly face problems of system survival or reliability. To solve those bottlenecks, a novel structural health monitoring (SHM) concept was proposed by utilizing the two dominant parameters of fractal theory, including the fractal dimension and the topothesy, to evaluate the instability condition of a bridge structure rapidly. To demonstrate the performance of this method, a series of experiments has been carried out. The function of the two parameters was first determined using data collected from a single bridge column scour test. As the fractal dimension gradually decreased, following the trend of the scour depth, it was treated as an alternative to the fundamental frequency of a bridge structure in the existing methods. Meanwhile, the potential of a positive correlation between the topothesy and the amplitude of vibration data was also investigated. The excellent sensitivity of the fractal parameters related to the scour depth was then demonstrated in a full-bridge experiment. Moreover, with the combination of these two parameters, a safety index to detect the critical scour condition was proposed. The experimental results have demonstrated that the critical scour condition can be predicted by the proposed safety index. The monitoring system developed greatly advances the field of bridge scour health monitoring and offers an alternative choice to traditional scour monitoring technology. (paper)

Scour in cohesive soils

Science.gov (United States)

2015-05-01

This study of scour in cohesive soils had two objectives. The first was to introduce and demonstrate a new ex situ erosion testing device (ESTD) that can mimic the near-bed flow of open channels to erode cohesive soils within a specified range of she...

Scour depth estimation using an equation based on wind tunnel experiments

Directory of Open Access Journals (Sweden)

Tsutsui Takayuki

2016-01-01

Full Text Available Scour is the result of degradation and aggradation by wind or moving fluid in the front and back of a pole standing in sand, respectively, and is often observed at the bottom of bridge piers in rivers. In this study, we propose a method of estimating the scour depth around a cylindrical structure standing in sand. The relationships among the depth of the scour, the aspect ratio of the structure (= height/diameter, the fluid velocity, and the sand properties (particle size and density were determined experimentally using a wind tunnel. The experiments were carried out under clear-water scour conditions. In the experiments, the aspect ratio of the cylindrical structure, the fluid velocity, and the sand particle size were varied systematically. The diameters of the structure were 20, 40, and 60 mm, and the aspect ratio was varied from 0.25 to 3.0. Sand particles of four sizes (200, 275, 475, and 600 μm were used in the experiment, and the velocity was varied from 4 to 11 m/s. The depth and radius of the scour were measured. As a result, we have developed an equation for estimating the scour depth that uses the aspect ratio, fluid velocity, and sand particle size as parameters.

Dynamic posturography using a new movable multidirectional platform driven by gravity.

NARCIS (Netherlands)

Commissaris, D.A.C.M.; Nieuwenhuijzen, P.H.J.A.; Overeem, S.; Vos, A. de; Duysens, J.E.J.; Bloem, B.R.

2002-01-01

Human upright balance control can be quantified using movable platforms driven by servo-controlled torque motors (dynamic posturography). We introduce a new movable platform driven by the force of gravity acting upon the platform and the subject standing on it. The platform consists of a 1 m2 metal

Dynamic posturography using a new movable multidirectional platform driven by gravity

NARCIS (Netherlands)

Commissaris, D.A.C.M.; Nieuwenhuijzen, P.H.J.A.; Overeem, S.; Vos, A. de; Duysens, J.E.J.; Bloem, B.R.

2002-01-01

Human upright balance control can be quantified using movable platforms driven by servo-controlled torque motors (dynamic posturography). We introduce a new movable platform driven by the force of gravity acting upon the platform and the subject standing on it. The platform consists of a 1 m(2)

Bridge scour conference shares knowledge and innovations : Tech Transfer Spotlight

Science.gov (United States)

2018-01-01

The National Cooperative Highway Research Programs Domestic Scan (NCHRP Project 20-68A) on bridge scour risk management brought more than 30 national bridge scour experts together for a week in July 2016 to examine ways to prevent and remediate br...

Design and characteristics of the drive mechanism for movable limiters of JT-60, (1)

International Nuclear Information System (INIS)

Takashima, Tetsuo; Morishita, Osamu; Yamamoto, Masahiro; Shimizu, Masatsugu; Ohta, Mitsuru

1976-10-01

Two fast-acting movable rail limiters will be installed in a large Tokamak JT-60 being designed in JAERI. The movable limiter consists of a drive mechanism, a vacuum seal, a bearing, and a molybdenum rail limiter. Design of the drive mechanism for the movable limiter and experimental results on the driving characteristics in full scale are described. (auth.)

Trends of Abutment-Scour Prediction Equations Applied to 144 Field Sites in South Carolina

Science.gov (United States)

Benedict, Stephen T.; Deshpande, Nikhil; Aziz, Nadim M.; Conrads, Paul

2006-01-01

The U.S. Geological Survey conducted a study in cooperation with the Federal Highway Administration in which predicted abutment-scour depths computed with selected predictive equations were compared with field measurements of abutment-scour depth made at 144 bridges in South Carolina. The assessment used five equations published in the Fourth Edition of 'Evaluating Scour at Bridges,' (Hydraulic Engineering Circular 18), including the original Froehlich, the modified Froehlich, the Sturm, the Maryland, and the HIRE equations. An additional unpublished equation also was assessed. Comparisons between predicted and observed scour depths are intended to illustrate general trends and order-of-magnitude differences for the prediction equations. Field measurements were taken during non-flood conditions when the hydraulic conditions that caused the scour generally are unknown. The predicted scour depths are based on hydraulic conditions associated with the 100-year flow at all sites and the flood of record for 35 sites. Comparisons showed that predicted scour depths frequently overpredict observed scour and at times were excessive. The comparison also showed that underprediction occurred, but with less frequency. The performance of these equations indicates that they are poor predictors of abutment-scour depth in South Carolina, and it is probable that poor performance will occur when the equations are applied in other geographic regions. Extensive data and graphs used to compare predicted and observed scour depths in this study were compiled into spreadsheets and are included in digital format with this report. In addition to the equation-comparison data, Water-Surface Profile Model tube-velocity data, soil-boring data, and selected abutment-scour data are included in digital format with this report. The digital database was developed as a resource for future researchers and is especially valuable for evaluating the reasonableness of future equations that may be developed.

The timing of scour and fill in a gravel-bedded river measured with buried accelerometers

Science.gov (United States)

Gendaszek, Andrew S.; Magirl, Christopher S.; Czuba, Christiana R.; Konrad, Christopher P.

2013-01-01

A device that measures the timing of streambed scour and the duration of sediment mobilization at specific depths of a streambed was developed using data-logging accelerometers placed within the gravel substrate of the Cedar River, Washington, USA. Each accelerometer recorded its orientation every 20 min and remained stable until the surrounding gravel matrix mobilized as sediment was transported downstream and scour reached the level of the accelerometer. The accelerometer scour monitors were deployed at 26 locations in salmon-spawning habitat during the 2010–2011 flood season to record when the streambed was scoured to the depth of typical egg-pocket deposition. Scour was recorded at one location during a moderate high-flow event (65 m3/s; 1.25–1.5-year recurrence interval) and at 17 locations during a larger high-flow event (159 m3/s; 7-year recurrence interval). Accelerometer scour monitors recorded periods of intermittent sediment mobilization and stability within a high-flow event providing insight into the duration of scour. Most scour was recorded during the rising limb and at the peak of a flood hydrograph, though some scour occurred during sustained high flows following the peak of the flood hydrograph.

Estimation of potential scour at bridges on local government roads in South Dakota, 2009-12

Science.gov (United States)

Thompson, Ryan F.; Wattier, Chelsea M.; Liggett, Richard R.; Truax, Ryan A.

2014-01-01

In 2009, the U.S. Geological Survey and South Dakota Department of Transportation (SDDOT) began a study to estimate potential scour at selected bridges on local government (county, township, and municipal) roads in South Dakota. A rapid scour-estimation method (level-1.5) and a more detailed method (level-2) were used to develop estimates of contraction, abutment, and pier scour. Data from 41 level-2 analyses completed for this study were combined with data from level-2 analyses completed in previous studies to develop new South Dakota-specific regression equations: four regional equations for main-channel velocity at the bridge contraction to account for the widely varying stream conditions within South Dakota, and one equation for head change. Velocity data from streamgages also were used in the regression for average velocity through the bridge contraction. Using these new regression equations, scour analyses were completed using the level-1.5 method on 361 bridges on local government roads. Typically, level-1.5 analyses are completed at flows estimated to have annual exceedance probabilities of 1 percent (100-year flood) and 0.2 percent (500-year flood); however, at some sites the bridge would not pass these flows. A level-1.5 analysis was then completed at the flow expected to produce the maximum scour. Data presented for level-1.5 scour analyses at the 361 bridges include contraction, abutment, and pier scour. Estimates of potential contraction scour ranged from 0 to 32.5 feet for the various flows evaluated. Estimated potential abutment scour ranged from 0 to 40.9 feet for left abutments, and from 0 to 37.7 feet for right abutments. Pier scour values ranged from 2.7 to 31.6 feet. The scour depth estimates provided in this report can be used by the SDDOT to compare with foundation depths at each bridge to determine if abutments or piers are at risk of being undermined by scour at the flows evaluated. Replicate analyses were completed at 24 of the 361 bridges

Informational Entropy and Bridge Scour Estimation under Complex Hydraulic Scenarios

Science.gov (United States)

Pizarro, Alonso; Link, Oscar; Fiorentino, Mauro; Samela, Caterina; Manfreda, Salvatore

2017-04-01

Bridges are important for society because they allow social, cultural and economic connectivity. Flood events can compromise the safety of bridge piers up to the complete collapse. The Bridge Scour phenomena has been described by empirical formulae deduced from hydraulic laboratory experiments. The range of applicability of such models is restricted by the specific hydraulic conditions or flume geometry used for their derivation (e.g., water depth, mean flow velocity, pier diameter and sediment properties). We seek to identify a general formulation able to capture the main dynamic of the process in order to cover a wide range of hydraulic and geometric configuration, allowing to extend our analysis in different contexts. Therefore, exploiting the Principle of Maximum Entropy (POME) and applying it on the recently proposed dimensionless Effective flow work, W*, we derived a simple model characterized by only one parameter. The proposed Bridge Scour Entropic (BRISENT) model shows good performances under complex hydraulic conditions as well as under steady-state flow. Moreover, the model was able to capture the evolution of scour in several hydraulic configurations even if the model contains only one parameter. Furthermore, results show that the model parameter is controlled by the geometric configurations of the experiment. This offers a possible strategy to obtain a priori model parameter calibration. The BRISENT model represents a good candidate for estimating the time-dependent scour depth under complex hydraulic scenarios. The authors are keen to apply this idea for describing the scour behavior during a real flood event. Keywords: Informational entropy, Sediment transport, Bridge pier scour, Effective flow work.

Movable MEMS Devices on Flexible Silicon

KAUST Repository

Ahmed, Sally

2013-05-05

Flexible electronics have gained great attention recently. Applications such as flexible displays, artificial skin and health monitoring devices are a few examples of this technology. Looking closely at the components of these devices, although MEMS actuators and sensors can play critical role to extend the application areas of flexible electronics, fabricating movable MEMS devices on flexible substrates is highly challenging. Therefore, this thesis reports a process for fabricating free standing and movable MEMS devices on flexible silicon substrates; MEMS flexure thermal actuators have been fabricated to illustrate the viability of the process. Flexure thermal actuators consist of two arms: a thin hot arm and a wide cold arm separated by a small air gap; the arms are anchored to the substrate from one end and connected to each other from the other end. The actuator design has been modified by adding etch holes in the anchors to suit the process of releasing a thin layer of silicon from the bulk silicon substrate. Selecting materials that are compatible with the release process was challenging. Moreover, difficulties were faced in the fabrication process development; for example, the structural layer of the devices was partially etched during silicon release although it was protected by aluminum oxide which is not attacked by the releasing gas . Furthermore, the thin arm of the thermal actuator was thinned during the fabrication process but optimizing the patterning and etching steps of the structural layer successfully solved this problem. Simulation was carried out to compare the performance of the original and the modified designs for the thermal actuators and to study stress and temperature distribution across a device. A fabricated thermal actuator with a 250 μm long hot arm and a 225 μm long cold arm separated by a 3 μm gap produced a deflection of 3 μm before silicon release, however, the fabrication process must be optimized to obtain fully functioning

Development of scour in non-cohesive sediments under a poorly erodible top layer

NARCIS (Netherlands)

Van Zuylen, J.A.; Sloff, C.J.

2015-01-01

This study deals with the development of deep scour holes in the river bed of the Dutch Rhine delta in the Netherlands. Assessment of multi-beam surveys, laboratory-flume experiments, and 3D numerical modelling, shows how fast this type of scour holes grows in depth and width. These typical scour

Flow and edge scour in current adjacent to stone covers

DEFF Research Database (Denmark)

Petersen, Thor U.; Sumer, B. Mutlu; Bøgelund, Jon

2015-01-01

This paper presents the results of an experimental investigation on edge scour adjacent to a stone cover laid on a sandy bed. The three-dimensional flow over the edge of the stone layer has been investigated by the use of particle image velocimetry. The flow measurements show a significant amount...... of turbulence in the primary flow near the junction between the stone layer and the sand bed and the formation of complex secondary-flow structures. The results show that the flow and the edge scour process in a steady current are governed by the size of the roughness elements and to some extent the side slope...... of the berm. The edge scour is caused by the combined action of the primary flow and the secondary flow. The primary flow stirs up the sediment and puts it into suspension, and the secondary flow carries it away from the junction between the stone layer and the sand bed, resulting in a scour hole forming...

Contraction rate, flow modification and bed layering impact on scour at the elliptical guide banks

Science.gov (United States)

Gjunsburgs, B.; Jaudzems, G.; Bizane, M.; Bulankina, V.

2017-10-01

Flow contraction by the bridge crossing structures, intakes, embankments, piers, abutments and guide banks leads to general scour and the local scour in the vicinity of the structures. Local scour is depending on flow, river bed and structures parameters and correct understanding of the impact of each parameter can reduce failure possibility of the structures. The paper explores hydraulic contraction, the discharge redistribution between channel and floodplain during the flood, local flow modification and river bed layering on depth, width and volume of scour hole near the elliptical guide banks on low-land rivers. Experiments in a flume, our method for scour calculation and computer modelling results confirm a considerable impact of the contraction rate of the flow, the discharge redistribution between channel and floodplain, the local velocity, backwater and river bed layering on the depth, width, and volume of scour hole in steady and unsteady flow, under clear water condition. With increase of the contraction rate of the flow, the discharge redistribution between channel and floodplain, the local velocity, backwater values, the scour depth increases. At the same contraction rate, but at a different Fr number, the scour depth is different: with increase in the Fr number, the local velocity, backwater, scour depth, width, and volume is increasing. Acceptance of the geometrical contraction of the flow, approach velocity and top sand layer of the river bed for scour depth calculation as accepted now, may be the reason of the structures failure and human life losses.

Analysis of experimental data sets for local scour depth around ...

African Journals Online (AJOL)

The performance of soft computing techniques to analyse and interpret the experimental data of local scour depth around bridge abutment, measured at different laboratory conditions and environment, is presented. The scour around bridge piers and abutments is, in the majority of cases, the main reason for bridge failures.

Scour depth estimation using an equation based on wind tunnel experiments

OpenAIRE

Tsutsui Takayuki

2016-01-01

Scour is the result of degradation and aggradation by wind or moving fluid in the front and back of a pole standing in sand, respectively, and is often observed at the bottom of bridge piers in rivers. In this study, we propose a method of estimating the scour depth around a cylindrical structure standing in sand. The relationships among the depth of the scour, the aspect ratio of the structure (= height/diameter), the fluid velocity, and the sand properties (particle size and density) were d...

Pier and contraction scour prediction in cohesive soils at selected bridges in Illinois

Science.gov (United States)

Straub, Timothy D.; Over, Thomas M.

2010-01-01

This report presents the results of testing the Scour Rate In Cohesive Soils-Erosion Function Apparatus (SRICOS-EFA) method for estimating scour depth of cohesive soils at 15 bridges in Illinois. The SRICOS-EFA method for complex pier and contraction scour in cohesive soils has two primary components. The first component includes the calculation of the maximum contraction and pier scour (Zmax). The second component is an integrated approach that considers a time factor, soil properties, and continued interaction between the contraction and pier scour (SRICOS runs). The SRICOS-EFA results were compared to scour prediction results for non-cohesive soils based on Hydraulic Engineering Circular No. 18 (HEC-18). On average, the HEC-18 method predicted higher scour depths than the SRICOS-EFA method. A reduction factor was determined for each HEC-18 result to make it match the maximum of three types of SRICOS run results. The unconfined compressive strength (Qu) for the soil was then matched with the reduction factor and the results were ranked in order of increasing Qu. Reduction factors were then grouped by Qu and applied to each bridge site and soil. These results, and comparison with the SRICOS Zmax calculation, show that less than half of the reduction-factor method values were the lowest estimate of scour; whereas, the Zmax method values were the lowest estimate for over half. A tiered approach to predicting pier and contraction scour was developed. There are four levels to this approach numbered in order of complexity, with the fourth level being a full SRICOS-EFA analysis. Levels 1 and 2 involve the reduction factors and Zmax calculation, and can be completed without EFA data. Level 3 requires some surrogate EFA data. Levels 3 and 4 require streamflow for input into SRICOS. Estimation techniques for both EFA surrogate data and streamflow data were developed.

BRISENT: An Entropy-Based Model for Bridge-Pier Scour Estimation under Complex Hydraulic Scenarios

Directory of Open Access Journals (Sweden)

Alonso Pizarro

2017-11-01

Full Text Available The goal of this paper is to introduce the first clear-water scour model based on both the informational entropy concept and the principle of maximum entropy, showing that a variational approach is ideal for describing erosional processes under complex situations. The proposed bridge–pier scour entropic (BRISENT model is capable of reproducing the main dynamics of scour depth evolution under steady hydraulic conditions, step-wise hydrographs, and flood waves. For the calibration process, 266 clear-water scour experiments from 20 precedent studies were considered, where the dimensionless parameters varied widely. Simple formulations are proposed to estimate BRISENT’s fitting coefficients, in which the ratio between pier-diameter and sediment-size was the most critical physical characteristic controlling scour model parametrization. A validation process considering highly unsteady and multi-peaked hydrographs was carried out, showing that the proposed BRISENT model reproduces scour evolution with high accuracy.

Level II scour analysis for Bridge 33 (TUNBTH00450033) on Town Highway 45, crossing the First Branch White River, Tunbridge, Vermont

Science.gov (United States)

Wild, E.C.; Severance, Timothy

1997-01-01

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.

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

Science.gov (United States)

Wild, Emily C.

1997-01-01

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.

HEC-RAS 2.2 for backwater and scour analysis - phase one

Science.gov (United States)

2000-09-01

The Kansas Department of Transportation (KDOT) and most bridge consultants in Kansas have been using the DOS-WSPRO program and the KDOT scour spreadsheets to perform bridge hydraulics and scour analysis for the past several years. Unfortunately, DOS-...

Impact of environmental factors on the distribution of extreme scouring (gouging) event, Canadian Beaufort shelf

Energy Technology Data Exchange (ETDEWEB)

Blasco, Steve [Geological Survey of Canada, Dartmouth (Canada); Carr, Erin; Campbell, Patrick [Canadian Seabed Research Ltd., Porters Lake (Canada); Shearer, Jim [Shearer Consulting, Ottawa (Canada)

2011-07-01

A knowledge of the presence of scours, their dimensions and their return frequencies is highly important in the development of hydrocarbon offshore structures. Mapping surveys have identified 290 extreme scour events across the Canadian Beaufort shelf. This paper investigated the impact of environmental factors on the distribution of extreme scouring events in the Canadian Beaufort shelf. This study used the NEWBASE database of new ice scours to perform an analysis of the scours appearance mechanisms. The geotechnical zonation, the bathymetry and the shelf gradient were evaluated using these data. Estimation of the surficial sediment type, the surficial sediment thickness and sea ice regime were also made. It was found that the spatial distribution of extreme scour events is controlled by sea-ice regime, bathymetry and geotechnical zonation. The results obtained from mapping surveys suggested that the key controlling environmental factors may combine to limit the depth of extreme scour events to 5 meters.

Numerical modeling of local scour around hydraulic structure in sandy beds by dynamic mesh method

Science.gov (United States)

Fan, Fei; Liang, Bingchen; Bai, Yuchuan; Zhu, Zhixia; Zhu, Yanjun

2017-10-01

Local scour, a non-negligible factor in hydraulic engineering, endangers the safety of hydraulic structures. In this work, a numerical model for simulating local scour was constructed, based on the open source code computational fluid dynamics model OpenFOAM. We consider both the bedload and suspended load sediment transport in the scour model and adopt the dynamic mesh method to simulate the evolution of the bed elevation. We use the finite area method to project data between the three-dimensional flow model and the two-dimensional (2D) scour model. We also improved the 2D sand slide method and added it to the scour model to correct the bed bathymetry when the bed slope angle exceeds the angle of repose. Moreover, to validate our scour model, we conducted and compared the results of three experiments with those of the developed model. The validation results show that our developed model can reliably simulate local scour.

Isolating the location of scour-induced stiffness loss in bridges using local modal behaviour

NARCIS (Netherlands)

Prendergast, L.J.; Gavin, K.; Hester, David

2017-01-01

Detecting scour by analysing bridge vibrations is receiving an increasing amount of attention in the literature. Others have considered changes in natural frequency to indicate the presence of scour damage; however, little work has been reported on identifying the location of a scour hole based

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

Science.gov (United States)

Burns, Ronda L.; Wild, Emily C.

1998-01-01

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.

Experimental Investigation on the Scour Hole Geometric Dimensions in Different Spur Dikes in 90 Degree Bend for Non-Submerged Conditions

Directory of Open Access Journals (Sweden)

somayeh rahimi

2017-06-01

Full Text Available Introduction: Outer bank region is always exposed to destruction and scour due to secondary flow. Different methods are generally used to protect the outer bank. One of the most common and economical ways is spur dike. As an obstacle in the flow, spur dikes protect the outer bank through decreasing the velocity and forming vortexes between them and as a result sedimentation along that area. However, the spur dike increases the shear stress and local scour around the spur, especially its nose.. This study investigates the scour hole dimensions around three types of spur dike including permeable, impermeable and bandal-like spur dike which is done as a combination of permeable and impermeable spur dike. Few studies were focused on field applications and laboratory experiments to investigate the practical applicability of the bandal-like structure in natural rivers. Rahman et al. (4 Studied the prediction of main channel degradation and local scour around hydraulic structures (impermeable and bandal-like spur dikes under non-submerged condition. Teraguchi et al. (9 Investigated the influenced of submerged condition on flow characteristics and sediment transport process caused by bandal-like structures with different spacing and alignment under live-bed scour condition through laboratory experiments. Materials and Methods: Experiments were carried out in the Physical Modeling Laboratory of Faculty of Water Science Engineering of Shahid Chamran University, Ahwaz. The main channel consisted of a 5m long upstream and a 3m long downstream straight reaches. A 90 degree bend was located between the two straight reach. The channel was of rectangular cross section, having a width of 0.7m and depth of 0.6m, with mild bends (ratio of radius to a width equal to 4 and it was filled with almost uniform sediment with a median particle size of D50=1.5 mm. The discharges were measured using an ultrasonic flow meter, which was installed on the pipe inlet of the

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

Science.gov (United States)

Wild, Emily C.; Degnan, James R.

1997-01-01

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.

49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.312 Movable bridge, interlocking of signal...

Bottom Scour Observed Under Hurricane Ivan

National Research Council Canada - National Science Library

Teague, William J; Jarosz, Eva; Keen, Timothy R; Wang, David W; Hulbert, Mark S

2006-01-01

Observations that extensive bottom scour along the outer continental shelf under Hurricane Ivan resulted in the displacement of more than 100 million cubic meters of sediment from a 35x15 km region...

Movable geometry and eigenvalue search capability in the MC21 Monte Carlo code

International Nuclear Information System (INIS)

Gill, D. F.; Nease, B. R.; Griesheimer, D. P.

2013-01-01

A description of a robust and flexible movable geometry implementation in the Monte Carlo code MC21 is described along with a search algorithm that can be used in conjunction with the movable geometry capability to perform eigenvalue searches based on the position of some geometric component. The natural use of the combined movement and search capability is searching to critical through variation of control rod (or control drum) position. The movable geometry discussion provides the mathematical framework for moving surfaces in the MC21 combinatorial solid geometry description. A discussion of the interface between the movable geometry system and the user is also described, particularly the ability to create a hierarchy of movable groups. Combined with the hierarchical geometry description in MC21 the movable group framework provides a very powerful system for inline geometry modification. The eigenvalue search algorithm implemented in MC21 is also described. The foundations of this algorithm are a regula falsi search though several considerations are made in an effort to increase the efficiency of the algorithm for use with Monte Carlo. Specifically, criteria are developed to determine after each batch whether the Monte Carlo calculation should be continued, the search iteration can be rejected, or the search iteration has converged. These criteria seek to minimize the amount of time spent per iteration. Results for the regula falsi method are shown, illustrating that the method as implemented is indeed convergent and that the optimizations made ultimately reduce the total computational expense. (authors)

Movable geometry and eigenvalue search capability in the MC21 Monte Carlo code

Energy Technology Data Exchange (ETDEWEB)

Gill, D. F.; Nease, B. R.; Griesheimer, D. P. [Bettis Atomic Power Laboratory, PO Box 79, West Mifflin, PA 15122 (United States)

2013-07-01

A description of a robust and flexible movable geometry implementation in the Monte Carlo code MC21 is described along with a search algorithm that can be used in conjunction with the movable geometry capability to perform eigenvalue searches based on the position of some geometric component. The natural use of the combined movement and search capability is searching to critical through variation of control rod (or control drum) position. The movable geometry discussion provides the mathematical framework for moving surfaces in the MC21 combinatorial solid geometry description. A discussion of the interface between the movable geometry system and the user is also described, particularly the ability to create a hierarchy of movable groups. Combined with the hierarchical geometry description in MC21 the movable group framework provides a very powerful system for inline geometry modification. The eigenvalue search algorithm implemented in MC21 is also described. The foundations of this algorithm are a regula falsi search though several considerations are made in an effort to increase the efficiency of the algorithm for use with Monte Carlo. Specifically, criteria are developed to determine after each batch whether the Monte Carlo calculation should be continued, the search iteration can be rejected, or the search iteration has converged. These criteria seek to minimize the amount of time spent per iteration. Results for the regula falsi method are shown, illustrating that the method as implemented is indeed convergent and that the optimizations made ultimately reduce the total computational expense. (authors)

Development of a three-dimensionally movable phantom system for dosimetric verifications

International Nuclear Information System (INIS)

Nakayama, Hiroshi; Mizowaki, Takashi; Narita, Yuichiro; Kawada, Noriyuki; Takahashi, Kunio; Mihara, Kazumasa; Hiraoka, Masahiro

2008-01-01

The authors developed a three-dimensionally movable phantom system (3D movable phantom system) which can reproduce three-dimensional movements to experimentally verify the impact of radiotherapy treatment-related movements on dose distribution. The phantom system consists of three integrated components: a three-dimensional driving mechanism (3D driving mechanism), computer control system, and phantoms for film dosimetry. The 3D driving mechanism is a quintessential part of this system. It is composed of three linear-motion tables (single-axis robots) which are joined orthogonally to each other. This mechanism has a motion range of 100 mm, with a maximum velocity of 200 mm/s in each dimension, and 3D motion ability of arbitrary patterns. These attributes are sufficient to reproduce almost all organ movements. The positional accuracy of this 3D movable phantom system in a state of geostationary is less than 0.1 mm. The maximum error in terms of the absolute position on movement was 0.56 mm. The positional reappearance error on movement was up to 0.23 mm. The observed fluctuation of time was 0.012 s in the cycle of 4.5 s of oscillation. These results suggested that the 3D movable phantom system exhibited a sufficient level of accuracy in terms of geometry and timing to reproduce interfractional organ movement or setup errors in order to assess the influence of these errors on high-precision radiotherapy such as stereotactic irradiation and intensity-modulated radiotherapy. In addition, the authors 3D movable phantom system will also be useful in evaluating the adequacy and efficacy of new treatment techniques such as gating or tracking radiotherapy

Technical improvements for the dynamic measurement of general scour and landslides

Science.gov (United States)

Chung Yang, Han; Su, Chih Chiang

2017-04-01

Disasters occurring near riverbeds, such as landslides, earth slides, debris flow, and general scour, are easily caused by flooding from typhoons. The occurrence of each type of disaster involves a process, so if a disaster event can be monitored in real time, hazards can be predicted, thereby enabling early warnings that could reduce the degree of loss engendered by the disaster. The study of technical improvements for the dynamic measurement of general scour and landslides could help to release these early warnings. In this study, improved wireless tracers were set up on site to ensure the feasibility of the improved measurement technology. A wireless tracer signal transmission system was simultaneously set up to avoid danger to surveyors caused by them having to be on site to take measurements. In order to understand the real-time dynamic riverbed scouring situation, after the flow path of the river was confirmed, the sites for riverbed scouring observation were established at the P30 pier of the Dajia River Bridge of National Highway No. 3, and approximately 100 m both upstream and downstream (for a total of three sites). A rainy event that caused riverbed erosion occurred in May 2015, and subsequently, Typhoons Soudelor, Goni, and Dujuan caused further erosion in the observed area. The results of the observations of several flood events revealed that wireless tracers can reflect the change in riverbed scour depth caused by typhoons and flooding in real time. The wireless tracer technique can be applied to real-time dynamic scouring observation of rivers, and these improvements in measurement technology could be helpful in preventing landslides in the future.

Longitudinal Pipeline Scour Propagation Induced by Wave-Current Interaction For the South Sumatra-West Java Submarine Pipeline

Science.gov (United States)

Suntoyo; Perkasa, B.; Atikasari, T. J.; Wisudawan, A.

2018-03-01

Scouring process around subsea pipelines could reduce the soil bearing capacity which affected to the pipe stability. Scouring initial process against time should be known to discover scouring propagation. This paper aims to analyze the time scale calculation of 32 inch diameter in-trench pipe, until meet the maximum-scouring-depth stage. Embedment (e/D) variation is given to know the impact to the scour propagation. Wave and current condition presented to meet the real condition. Wave orbital particle velocity (Uw) is calculated to obtain the non-dimensional factors (Uc/(Uc+Uw)) and KC. The results showed according to the deeper pipe embedment, it takes longer time to reach the maximum scouring depth.

Analytical model for local scour prediction around hydrokinetic turbine foundations

Science.gov (United States)

Musa, M.; Heisel, M.; Hill, C.; Guala, M.

2017-12-01

Marine and Hydrokinetic renewable energy is an emerging sustainable and secure technology which produces clean energy harnessing water currents from mostly tidal and fluvial waterways. Hydrokinetic turbines are typically anchored at the bottom of the channel, which can be erodible or non-erodible. Recent experiments demonstrated the interactions between operating turbines and an erodible surface with sediment transport, resulting in a remarkable localized erosion-deposition pattern significantly larger than those observed by static in-river construction such as bridge piers, etc. Predicting local scour geometry at the base of hydrokinetic devices is extremely important during foundation design, installation, operation, and maintenance (IO&M), and long-term structural integrity. An analytical modeling framework is proposed applying the phenomenological theory of turbulence to the flow structures that promote the scouring process at the base of a turbine. The evolution of scour is directly linked to device operating conditions through the turbine drag force, which is inferred to locally dictate the energy dissipation rate in the scour region. The predictive model is validated using experimental data obtained at the University of Minnesota's St. Anthony Falls Laboratory (SAFL), covering two sediment mobility regimes (clear water and live bed), different turbine designs, hydraulic parameters, grain size distribution and bedform types. The model is applied to a potential prototype scale deployment in the lower Mississippi River, demonstrating its practical relevance and endorsing the feasibility of hydrokinetic energy power plants in large sandy rivers. Multi-turbine deployments are further studied experimentally by monitoring both local and non-local geomorphic effects introduced by a twelve turbine staggered array model installed in a wide channel at SAFL. Local scour behind each turbine is well captured by the theoretical predictive model. However, multi

“GEOHeritage” - GIS Based Application for Movable Heritage

Directory of Open Access Journals (Sweden)

Albina Moscicka

2011-12-01

Full Text Available The paper will present the results of a research project „A methodology for mapping movable heritage”.  This project, financed by the Polish Ministry of Science and Higher Education in 2008-2010, was realized by the Institute of Geodesy and Cartography in cooperation with the Research and Academic Computer Network (portal Polska.pl, the Central Archives of Historical Records and Department of Art History of the Wroclaw University. The idea of the project was to simplify access to digital movable cultural heritage by the use of spatial information. The main aspect of the project was to use a Geographic Information System (GIS - as a technology and as a tool - to integrate different digital collections, present their content in one space and provide online access to them from one common level – from an online map. The essence of the research was to present on the online map movable monument as multi-spatial object. The base of this assumption is that most of monuments, especially movable ones, can have several places in the geographical space that are connected with them (several various space relations. As a rule archival documents were created in one place, describe the other, today can be kept in places far away from the place they were prepared, and what more the parts of the same collection can be kept in different archives. Moreover, one single document can be connected or have relations (typological, thematically, temporal, spatial with other relations to the same or the other one. The reason for it is that documents concerning various places are housed in the same archive, various documents can present the same place or the place of creating particular document can be the place of housing another. In the project the basic source material was digital collections of original records. Their metadata defined in the international standards of monuments’ description were used for connecting digital monuments with the geographic space

Predicting Scour of Bedrock in Wisconsin

Science.gov (United States)

2017-04-01

This research evaluates the scour potential of rocks supporting Wisconsin DOT bridge foundations. Ten highway bridges were selected for this study, of which seven are supported by shallow foundations, and five were built on sandstone in rivers/stream...

Influence of Persistent Wind Scour on the Surface Mass Balance of Antarctica

Science.gov (United States)

Das, Indrani; Bell, Robin E.; Scambos, Ted A.; Wolovick, Michael; Creyts, Timothy T.; Studinger, Michael; Fearson, Nicholas; Nicolas, Julien P.; Lenaerts, Jan T. M.; vandenBroeke, Michiel R.

2013-01-01

Accurate quantification of surface snow accumulation over Antarctica is a key constraint for estimates of the Antarctic mass balance, as well as climatic interpretations of ice-core records. Over Antarctica, near-surface winds accelerate down relatively steep surface slopes, eroding and sublimating the snow. This wind scour results in numerous localized regions (Antarctica. The scour zones are persistent because they are controlled by bedrock topography. On the basis of our Dome A observations, we develop an empirical model to predict wind-scour zones across the Antarctic continent and find that these zones are predominantly located in East Antarctica. We estimate that approx. 2.7-6.6% of the surface area of Antarctica has persistent negative net accumulation due to wind scour, which suggests that, across the continent, the snow mass input is overestimated by 11-36.5 Gt /yr in present surface-mass-balance calculations.

New types of time domain reflectometry sensing waveguides for bridge scour monitoring

Science.gov (United States)

Lin, Chih-Ping; Wang, Kai; Chung, Chih-Chung; Weng, Yu-Wen

2017-07-01

Scour is a major threat to bridge safety, especially in harsh fluvial environments. Real-time monitoring of bridge scour is still very limited due to the lack of robust and economic scour monitoring device. Time domain reflectometry (TDR) is an emerging waveguide-based technique holding great promise to develop more durable scour monitoring devices. This study presents new types of TDR sensing waveguides in forms of either sensing rod or sensing wire, taking into account of the measurement range, durability, and ease of field installation. The sensing rod is composed of a hollow grooved steel rod paired up with a metal strip on the insulating groove, while the sensing wire consists of two steel strands with one of them coated with an insulating jacket. The measurement sensitivity is inevitably sacrificed when other properties such as the measurement range, field durability, and installation easiness are enhanced. Factors affecting the measurement sensitivity were identified and experimentally evaluated for better arranging the waveguide conductors. A data reduction method for scour-depth estimation without the need for identifying the sediment/water reflection and a two-step calibration procedure for rating propagation velocities were proposed to work with the new types of TDR sensing waveguides. Both the calibration procedure and the data reduction method were experimentally validated. The test results indicated that the new TDR sensing waveguide provides accurate scour depth measurements regardless of the sacrificed sensitivity. The insulating coating of the new TDR sensing waveguide was also demonstrated to be effective in extending the measurement range up to at least 15 m.

Autonomous measurements of bridge pier and abutment scour using motion-sensing radio transmitters : technical transfer summary.

Science.gov (United States)

2010-01-01

Scour around the foundations (piers and abutments) of a bridge due to river flow is often referred to as bridge scour. Bridge scour is a problem of national scope that has dramatic impacts on economics and safety of the traveling public. Bridge...

Backfilling of a Scour Hole around a Pile in Waves and Current

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Petersen, Thor Ugelvig; Locatelli, Luca

2013-01-01

This paper presents the results of an experimental investigation of the backfilling of scour holes around circular piles. Scour holes around a pile are generated either by a current or a wave. Subsequently, the flow climate is changed from current to wave, combined waves and current, or wave...... around the pile for the same wave (or combined waves and current) climate. The time scale of backfilling has been determined as a function of three parameters, namely, (1) the Keulegan-Carpenter number of the initial wave or current (which generates the initial scour hole); (2) that of the subsequent...

Observations of Scour and Transport at Coastal Structures from the 2011 Tohoku Tsunami - Implications for Flow in Natural Terrain

Science.gov (United States)

Petroff, C. M.

2011-12-01

Before the March 11, 2011 Tohoku tsunami, many communities along the Japan coast had shore protection barriers, some designed specifically to provide protection from tsunamis and others for typhoon and storm surge protection. A vast number of these structures were overtopped, damaged or destroyed by the high inundation and currents generated in the tsunami. Observations are presented about scour features at man-made coastal structures in the Tohoku region as well as the hydraulic transport of debris from these structures. Along with providing lessons for structure design and maintenance, these observations have implications for hydraulic transport in natural terrain, not only at hard points such as rock outcrops but also at other features such as river mouths, barrier islands and coastal dunes. As an example, Photo 1 shows the overtopping flow at the seawall at Noda, in the Iwate prefecture. From the point of view of hydraulics the type of flow seen in the photo is more like that at an in-line weir or spillway than the wave conditions for which the structure was designed. On the lee or downstream side of such structures, the flow is supercritical resulting in a supercritical to subcritical transition near the landward toe of the seawall. High flow velocities along with increased pore pressure and overturning flow create very deep scour in these locations Such as the zone clearly seen in Photo 2 behind the seawall at the Sendai airport. It is anticipated that similar hydraulic conditions would occur for flow over a high coastal dune ridge where the ridge would act as a flow control point and locally high velocities on the landward side of the ridge would result in high erosion and scour. Other examples are given.

Experimental and Numerical Investigation of Local Scour Around Submarine Piggyback Pipeline Under Steady Current

Science.gov (United States)

Zhao, Enjin; Shi, Bing; Qu, Ke; Dong, Wenbin; Zhang, Jing

2018-04-01

As a new type of submarine pipeline, the piggyback pipeline has been gradually adopted in engineering practice to enhance the performance and safety of submarine pipelines. However, limited simulation work and few experimental studies have been published on the scour around the piggyback pipeline under steady current. This study numerically and experimentally investigates the local scour of the piggyback pipe under steady current. The influence of prominent factors such as pipe diameter, inflow Reynolds number, and gap between the main and small pipes, on the maximum scour depth have been examined and discussed in detail. Furthermore, one formula to predict the maximum scour depth under the piggyback pipeline has been derived based on the theoretical analysis of scour equilibrium. The feasibility of the proposed formula has been effectively calibrated by both experimental data and numerical results. The findings drawn from this study are instructive in the future design and application of the piggyback pipeline.

Scour around monopile foundations for off-shore wind turbines

DEFF Research Database (Denmark)

Margheritini, Lucia; Frigaard, Peter; Martinelli, Luca

2006-01-01

The present paper aims to describe the scour hole process around large piles through laboratory tests under waves, unidirectional and tidal currents in time. The process for unidirectional and tidal currents has been compared. The tests have been carried out in a wave flume equipped with a two wa...... recirculation pump at the Hydraulic Laboratory at Aalborg University. The mobile bed around the model was leveled with an automatic laser profiler and the results are graphically displayed as maximum scour depths and eroded volumes....

Modelling the flow structure in local scour around bridge pier

International Nuclear Information System (INIS)

Ghani, U.

2014-01-01

Bridge pier scouring is an important issue of any bridge design work. If it is not taken into account properly, then results will be disastrous. A number of bridges have failed due to clear water local scouring of piers. This research paper presents a numerical model study in which an attempt has been made to explore the flow variables which exist in and around a scoured bridge pier. A finite volume based model of bridge pier was developed using 3D (Three Dimensional) numerical code FLUENT and GAMBIT. After validation process, different discharge values were considered and its impact on three dimensional characteristics of flow such as stream-wise velocities on longitudinal and transverse sections, turbulance circulation cells, and boundary shear stresses was investigated. It was observed that increasing the discharge results in more turbulance around the pier on its downstream side and turbulence properties are intensified in such a situation. However, the primary velocities on the downstream side remain almost unchanged. The results have been presented in the form of contours, vector of primary velocities and x-y plots of bed shear stresses. This study can be used for enhanced understanding of flow features and improvement of formulae for prediction of scour holes around piers. (author)

New movable plate for efficient millimeter wave vertical on-chip antenna

KAUST Repository

Marnat, Loic; Carreno, Armando Arpys Arevalo; Conchouso Gonzalez, David; Galicia Martinez, Miguel Angel; Foulds, Ian G.; Shamim, Atif

2013-01-01

A new movable plate concept is presented in this paper to realize mm-wave vertical on-chip antennas through MEMS based post-processing steps in a CMOS compatible process. By virtue of its vertical position, the antenna is isolated from the lossy Si substrate and hence performs with a better efficiency as compared to the horizontal position. In addition, the movable plate concept enables polarization diversity by providing both horizontal and vertical polarizations on the same chip. Through a first iteration fractal bowtie antenna design, dual band (60 and 77 GHz) operation is demonstrated in both horizontal and vertical positions without any change in dimensions or use of switches for two different mediums (Si and air). To support the movable plate concept, the transmission line and antenna are designed on a flexible polyamide, where the former has been optimized to operate in the bent position. The design is highly suitable for compact, low cost and efficient SoC solutions. © 1963-2012 IEEE.

New movable plate for efficient millimeter wave vertical on-chip antenna

KAUST Repository

Marnat, Loic

2013-04-01

A new movable plate concept is presented in this paper to realize mm-wave vertical on-chip antennas through MEMS based post-processing steps in a CMOS compatible process. By virtue of its vertical position, the antenna is isolated from the lossy Si substrate and hence performs with a better efficiency as compared to the horizontal position. In addition, the movable plate concept enables polarization diversity by providing both horizontal and vertical polarizations on the same chip. Through a first iteration fractal bowtie antenna design, dual band (60 and 77 GHz) operation is demonstrated in both horizontal and vertical positions without any change in dimensions or use of switches for two different mediums (Si and air). To support the movable plate concept, the transmission line and antenna are designed on a flexible polyamide, where the former has been optimized to operate in the bent position. The design is highly suitable for compact, low cost and efficient SoC solutions. © 1963-2012 IEEE.

Electromagnetic sensors for monitoring of scour and deposition processes at bridges and offshore wind turbines

Science.gov (United States)

Michalis, Panagiotis; Tarantino, Alessandro; Judd, Martin

2014-05-01

Recent increases in precipitation have resulted in severe and frequent flooding incidents. This has put hydraulic structures at high risk of failure due to scour, with severe consequences to public safety and significant economic losses. Foundation scour is the leading cause of bridge failures and one of the main climate change impacts to highway and railway infrastructure. Scour action is also being considered as a major risk for offshore wind farm developments as it leads to excessive excavation of the surrounding seabed. Bed level conditions at underwater foundations are very difficult to evaluate, considering that scour holes are often re-filled by deposited loose material which is easily eroded during smaller scale events. An ability to gather information concerning the evolution of scouring will enable the validation of models derived from laboratory-based studies and the assessment of different engineering designs. Several efforts have focused on the development of instrumentation techniques to measure scour processes at foundations. However, they are not being used routinely due to numerous technical and cost issues; therefore, scour continues to be inspected visually. This research project presents a new sensing technique, designed to measure scour depth variation and sediment deposition around the foundations of bridges and offshore wind turbines, and to provide an early warning of an impending structural failure. The monitoring system consists of a probe with integrated electromagnetic sensors, designed to detect the change in the surrounding medium around the foundation structure. The probe is linked to a wireless network to enable remote data acquisition. A developed prototype and a commercial sensor were evaluated to quantify their capabilities to detect scour and sediment deposition processes. Finite element modelling was performed to define the optimum geometric characteristics of the prototype scour sensor based on models with various permittivity

Clear-water abutment and contraction scour in the Coastal Plain and Piedmont Provinces of South Carolina, 1996-99

Science.gov (United States)

Benedict, Stephen T.

2016-01-01

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, collected observations of clear-water aburment and contraction scour at 146 bridges in the Coastal Plain and Piedmont of South Carolina. Scour depths ranged from 0 to 23.6 feet. Theoretical scour depths were computed at each bridge and compared with observed scour. This comparison showed that theoretical scour depths, in general, exceeded the observed scour depths and often were excessive. A comparison of field data with dimensionless relations for laboratory data showed that the range of dimensionless variables used in laboratory investigations was outside of the range for field data in South Carolina, suggesting laboratory relations may not be applicable to field conditions in South Carolina. Variables determined to be important in developing scour within laboratory studies were investigated to understand their influence within the South Carolina field data, and many of these variables appeared to be insignificant under field conditions found in South Carolina. The strongest explanatory variables were embankment length, geometric-contraction ratio, approach velocity, and soil cohesion. Envelope curves developed with the field data are useful tools for assessing reasonable ranges of scour depth in South Carolina. These tools are simple to apply and are an improvement over the current methods for predicting theoretical scour.

Design and Research of the Movable Hybrid Photovoltaic-Thermal (PVT System

Directory of Open Access Journals (Sweden)

Lian Zhang

2017-04-01

Full Text Available In recent years, with the development of photovoltaic system and photo-thermal system technology, hybrid photovoltaic-thermal (PVT technology has been a breakthrough in many aspects. This paper describes the movable hybrid PVT system from the aspects of appearance structure, energy flow, and control circuit. The system is equipped with rolling wheels and the simulated light sources also can be removed so that the system can be used in the outdoor conditions. The movable system is also suitable for the PVT system and its related applications without any external power supply. This system combines two technologies: photovoltaic power generation and photo-thermal utilization. The first part of the power supply is for the systems own output power supply, and the second part is for generating thermal energy. The two separate parts can be controlled and monitored respectively through the control circuits and the touch screens. The experimental results show that the system can generate 691 kWh electric energy and 3047.8 kWh thermal energy each year under normal working conditions. The efficiency of the proposed movable hybrid PVT system is calculated to be approximately 42.82% using the revised equations that are proposed in this paper. Therefore, the movable hybrid PVT system can meet the daily demands of hot water and electricity power in remote areas or islands and other non-grid areas. It also can be used to conduct experiment tests for the PVT system.

Experiences and future plans of movable mask system for the high current collider KEK B-factory

International Nuclear Information System (INIS)

Suetsugu, Yusuke; Kageyama, Tatsuya; Takeuchi, Yasunao; Kanazawa, Ken-ichi; Satoh, Kotarou; Sanami, Toshiya; Hirayama, Hideo

2002-01-01

The movable mask is a special device for an accelerator that cuts off spent particles near the beam orbit and reduces background of the detector. For the KEKB, an electron/positron collider with two rings, sixteen movable masks had been installed for each ring. The originally designed masks, however, revealed severe troubles of heating, arcing and vacuum leaks at the stored beam currents of several hundreds mA. Several kinds of improved masks had been designed employing RF technologies and were installed to the ring step by step. The latest masks are working well except for the grooves on the mask head. Here the problems of movable masks so far are summarized and the structures of the latest movable masks and their status are presented. (author)

49 CFR 236.787 - Protection, cross.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Protection, cross. 236.787 Section 236.787 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Protection, cross. An arrangement to prevent the improper operation of a signal, switch, movable-point frog...

Investigation of hydrodynamics on local scour by shape of single spur dike in river bend

International Nuclear Information System (INIS)

Masjedi, A; Foroushani, E P

2012-01-01

A series of experiments were conducted in which the the scour hole associated with model spur dike was measured in a 180 degree laboratory flume bend under clear-water overtopping flows. In this study, the local scour were conducted for three different shapes of oblong, rectangulat chamfered of straight spur dikes at the bend with various Froude number. The main goals of the experiments were to evaluate the effect of the three different shapes of straight spur dikes on the volume of scour and potential aquatic habitat and on minimizing erosion adjacent to the streambanks. The experiments showed that of the three different shapes of straight spur dikes tested, the least erosion of the around in the near bank region was associated with the spur dikes with oblong shape, while the greatest volume of the scour hole was associated with the rectangular shape. So it was observed that, as Froude number increases, the scour increases.

Method to Predict Long Time Span of Scour Around Offshore Wind Turbine Foundations

DEFF Research Database (Denmark)

Dixen, Martin; Lohmann, Iris P.; Christensen, Erik Damgaard

2012-01-01

tables have been made based on full 3D numerical simulations of the flow and sediment transport for fixed configurations of the scour hole. When changing the governing parameters which are causing the scour development around the structure, the erosion rate or backfilling rate can be calculated from...

Movability or Autonomy for Humans

KAUST Repository

Schnapp, Jeffrey

2018-01-18

A human-centered approach to the design of smart robotic vehicles Contrary to the feverish promises of early 20th century futurists, the romance of the road has driven humanity down a dead end. The civilization of speed, acceleration, and motorized mobility has transformed the world into a perpetual traffic jam. Entire cities are being sacrificed on the altar of automobility. The landscape is being reduced to a flyover and drive-through zone, fissured by asphalt ribbons, fracked to extract fuels whose combustion is cooking the globe. Nearly 80% of urban areas are wrapped in dense blankets of smog. People arenﾒt moving more: they are moving less and with greater difficulty. And they are facing the health consequences of the sedentary life-styles they have been encouraged to adopt. If this is era of mobility, then I believe itﾒs time to shift gears: from mobility to movability. In this lecture, Jeffrey Schnapp will discuss how Movability unfolds on the far more intimate, intelligent, human-scale of the emerging 21st century cityscape. Itﾒs the scale of autonomous land drones threading their way down busy sidewalks; the scale of smart cargo carts invisibly coupled to workers making last mile deliveries in pedestrian-only zones; the scale of electric microcars platooning like trains while stopping off at individual destinations for pickups and dropoffs; and the scale of civic spaces animated by new kinds of vehicles that help the aging or the mobility-impaired to improve the quality of their lives and extend the range of their activities.

Analysis of movable bus stop boarding and alighting areas.

Science.gov (United States)

2013-05-01

This study explored the feasibility of using movable and reusable boarding and alighting (B&A) pads at bus stops. : Potential design alternatives in terms of materials and structural support for these pads were evaluated. The review : focused on the ...

Automatic control of movable detectors

International Nuclear Information System (INIS)

Wassel, W.W.; Remley, G.W.

1980-01-01

An invention is described, relating to a microprocessor based control system for a plurality of movable detectors, e.g. a nuclear reactor flux mapping system, with new system architecture which increases system availability by preventing faults on any of the detection channels from disabling the remaining channels. The system has, say, four drive trains for a number of detectors. Functional separation is realized by having two channels control their associated two drive trains. Redundancy is provided by having dual channels for operator interface. Communications between the functionally separate channels is accomplished by employing two-ported memories in conjunction with multiple microprocessors. (author)

TFTR movable limiter instrumentation and controls

International Nuclear Information System (INIS)

Frankenberg, J.; Collins, D.; Kaufmann, D.; Mamoun, A.

1983-01-01

The TFTR movable limiter is a single poloidal limiter located within one 18 /SUP o/ segment of the vacuum vessel. It consists of three (3) interconnected inconel backing plates covered with titanium carbide coated graphite tiles. The backing plates are positioned by three independent screw drive actuators. Cooling water is fed through the horizontal port cover to tubes brazed onto the backs of the backing plates. Thermocouples monitor the limiter temperature. (1) and more fully described in refs. (1) and (2). The positioning actuators are driven by independently controlled DC servo motors, controlled either locally or from CICADA. Drive motor shaft position is monitored by chain driven encoders and potentiometers. Limiter blade position can be varied to suit any plasma within the operating range. CICADA is programmed to keep the limiter stroke within safe operating limits. A microprocessor duplicates the CICADA protective function allowing limiter operation without CICADA. The potentiometer signal is sent to an analog computer, which safeguards the limiter against failure of the encoders or the micro-processor. Cooling water flows through the limiter in 3 separate paths, one for each blade. The flow rate and temperature rise through each loop are measured accurately to allow CICADA to calculate the heat into each blade. The water system is also interlocked and alarmed to prevent dumping of water into the vacuum vessel

Analysis of Heat Stress and the Indoor Climate Control Requirements for Movable Refuge Chambers.

Science.gov (United States)

Hao, Xiaoli; Guo, Chenxin; Lin, Yaolin; Wang, Haiqiao; Liu, Heqing

2016-05-20

Movable refuge chambers are a new kind of rescue device for underground mining, which is believed to have a potential positive impact on reducing the rate of fatalities. It is likely to be hot and humid inside a movable refuge chamber due to the metabolism of trapped miners, heat generated by equipment and heat transferred from outside. To investigate the heat stress experienced by miners trapped in a movable refuge chamber, the predicted heat strain (PHS) model was used to simulate the heat transfer process between the person and the thermal environment. The variations of heat stress with the temperature and humidity inside the refuge chamber were analyzed. The effects of air temperature outside the refuge chamber and the overall heat transfer coefficient of the refuge chamber shell on the heat stress inside the refuge chamber was also investigated. The relationship between the limit of exposure duration and the air temperature and humidity was numerically analyzed to determine the upper limits of temperature and humidity inside a refuge chamber. Air temperature of 32 °C and relative humidity of 70% are recommended as the design standard for internal thermal environment control of movable refuge chambers.

Analysis of Heat Stress and the Indoor Climate Control Requirements for Movable Refuge Chambers

Directory of Open Access Journals (Sweden)

Xiaoli Hao

2016-05-01

Full Text Available Movable refuge chambers are a new kind of rescue device for underground mining, which is believed to have a potential positive impact on reducing the rate of fatalities. It is likely to be hot and humid inside a movable refuge chamber due to the metabolism of trapped miners, heat generated by equipment and heat transferred from outside. To investigate the heat stress experienced by miners trapped in a movable refuge chamber, the predicted heat strain (PHS model was used to simulate the heat transfer process between the person and the thermal environment. The variations of heat stress with the temperature and humidity inside the refuge chamber were analyzed. The effects of air temperature outside the refuge chamber and the overall heat transfer coefficient of the refuge chamber shell on the heat stress inside the refuge chamber was also investigated. The relationship between the limit of exposure duration and the air temperature and humidity was numerically analyzed to determine the upper limits of temperature and humidity inside a refuge chamber. Air temperature of 32 °C and relative humidity of 70% are recommended as the design standard for internal thermal environment control of movable refuge chambers.

CFD-DEM Onset of Motion Analysis for Application to Bed Scour Risk Assessment

Energy Technology Data Exchange (ETDEWEB)

Sitek, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-03-01

This CFD study with DEM was done as a part of the Federal Highway Administration’s (FHWA’s) effort to improve scour design procedures. The Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) model, available in CD-Adapco’s StarCCM+ software, was used to simulate multiphase systems, mainly those which combine fluids and solids. In this method the motion of discrete solids is accounted for by DEM, which applies Newton's laws of motion to every particle. The flow of the fluid is determined by the local averaged Navier–Stokes equations that can be solved using the traditional CFD approach. The interactions between the fluid phase and solids phase are modeled by use of Newton's third law. The inter-particle contact forces are included in the equations of motion. Soft-particle formulation is used, which allows particles to overlap. In this study DEM was used to model separate sediment grains and spherical particles laying on the bed with the aim to analyze their movement due to flow conditions. Critical shear stress causing the incipient movement of the sediment was established and compared to the available experimental data. An example of scour around a cylindrical pier is considered. Various depths of the scoured bed and flow conditions were taken into account to gain a better understanding of the erosion forces existing around bridge foundations. The decay of these forces with increasing scour depth was quantified with a ‘decay function’, which shows that particles become increasingly less likely to be set in motion by flow forces as a scour hole increases in depth. Computational and experimental examples of the scoured bed around a cylindrical pier are presented.

Effect of Submergence and Apron Length on Spillway Scour: Case Study

Directory of Open Access Journals (Sweden)

Seungho Hong

2015-10-01

Full Text Available Large-scale water resources systems are often managed by an integrated set of hydraulic structures that are vulnerable to wider ranges of discharge and tailwater elevation than envisioned in their original design due to climate change and additional project objectives such as fostering healthy ecosystems. The present physical model study explored the performance of a spillway structure on the Kissimmee River, operated by the South Florida Water Management District, under extreme conditions of drought and flooding with accompanying low and high tailwater levels for both gate-controlled and uncontrolled spillway flow conditions. Maximum scour depths and their locations for two different riprap apron lengths downstream of the spillway stilling basin were measured along with the complex flow fields prior to scour. Effects of tailwater submergence, type of spillway flow and riprap apron length on scour results are interpreted in terms of the measured turbulent kinetic energy and velocity distributions near the bed.

Reducing Local Scouring at Bridge Piles Using Collars and Geobags

Directory of Open Access Journals (Sweden)

Shatirah Akib

2014-01-01

Full Text Available The present study examines the use of collars and geobags for reducing local scour around bridge piles. The efficiency of collars and geobags was studied experimentally. The data from the experiments were compared with data from earlier studies on the use of single piles with a collar and with a geobag. The results showed that using a combination of a steel collar and a geobag yields the most significant scour reduction for the front and rear piles, respectively. Moreover, the independent steel collar showed better efficiency than the independent geobag below the sediment level around the bridge piles.

Bridge pier scour in cohesive soil: a review

Indian Academy of Sciences (India)

Y Sonia Devi

process and mechanism at bridge pier in cohesive and noncohesive soil are presented. The effects ... examples: one under laboratory condition and another under field condition. ..... not take part in scouring as these sediments are swept over.

Local Scour : Influence of an exponential eddy viscosity distribution on the longitudial flow velocity

NARCIS (Netherlands)

Hoffmans, G.J.C.M.

1988-01-01

The general purpose of this research project is to model mathematically the local scour downstream of a structure (2-D). The model has to simulate the development of the scour as a function of the time. Basically two models are necessary namely a flow model and a morphological model. The latter

The Power of Collateral : How Problems in Securing Transections Limit Private Credit from Movable Property

OpenAIRE

Fleisig, Heywood

1995-01-01

In many developing countries, faulty laws and regulations make it hard to use livestock, machines, equipment, standing crops, and other movable property as collateral. The resulting constraints on access to credit hurt economies. In Bolivia, for example, a faulty legal and regulatory framework for the use of movable property as collateral has led to a loss in GDP estimated at between 5 and...

Investigating the effect of curved shape of bridge abutment provided with collar on local scour, experimentally and numerically

Directory of Open Access Journals (Sweden)

Y. Abdallah Mohamed

2015-06-01

Full Text Available Scour around bridge supports such as abutments can result in structural collapse and loss of life and property, so there is a need to control and minimize the local scour depth. In this paper, numerical and experimental studies were carried out to investigate the effect of different relative radii of the bridge abutment provided with collar on local scour depth. A 3-D numerical model is developed to simulate the scour at bridge abutment using SSIIM program. This model solves 3-D Navier–Stokes equations and a bed load conservation equation. The k–ε turbulence model is used to solve the Reynolds-stress term. It was found the curvature shape of bridge abutment provided with collar could share to reduce the local scour depth by more 95%. In addition, the results of simulation models agree well with the experimental data.

Prediction of Scour Depth around Bridge Piers using Adaptive Neuro-Fuzzy Inference Systems (ANFIS)

Science.gov (United States)

Valyrakis, Manousos; Zhang, Hanqing

2014-05-01

Earth's surface is continuously shaped due to the action of geophysical flows. Erosion due to the flow of water in river systems has been identified as a key problem in preserving ecological health of river systems but also a threat to our built environment and critical infrastructure, worldwide. As an example, it has been estimated that a major reason for bridge failure is due to scour. Even though the flow past bridge piers has been investigated both experimentally and numerically, and the mechanisms of scouring are relatively understood, there still lacks a tool that can offer fast and reliable predictions. Most of the existing formulas for prediction of bridge pier scour depth are empirical in nature, based on a limited range of data or for piers of specific shape. In this work, the application of a Machine Learning model that has been successfully employed in Water Engineering, namely an Adaptive Neuro-Fuzzy Inference System (ANFIS) is proposed to estimate the scour depth around bridge piers. In particular, various complexity architectures are sequentially built, in order to identify the optimal for scour depth predictions, using appropriate training and validation subsets obtained from the USGS database (and pre-processed to remove incomplete records). The model has five variables, namely the effective pier width (b), the approach velocity (v), the approach depth (y), the mean grain diameter (D50) and the skew to flow. Simulations are conducted with data groups (bed material type, pier type and shape) and different number of input variables, to produce reduced complexity and easily interpretable models. Analysis and comparison of the results indicate that the developed ANFIS model has high accuracy and outstanding generalization ability for prediction of scour parameters. The effective pier width (as opposed to skew to flow) is amongst the most relevant input parameters for the estimation.

Vulnerability of bridges to scour:Insights from an international expert elicitation workshop

OpenAIRE

Lamb, Rob; Aspinall, Willy; Odbert, Henry; Wagener, Thorsten

2017-01-01

Scour (localised erosion) during flood events is one of the most significant threats to bridges over rivers and estuaries, and has been the cause of numerous bridge failures, with damaging consequences. Mitigation of the risk of bridges being damaged by scour is therefore important to many infrastructure owners, and is supported by industry guidance. Even after mitigation, some residual risk remains, though its extent is difficult to quantify because of the uncertainties inherent in the predi...

Effect of Scour on the Natural Frequency Responses of the Meteorological Mast in the Taiwan Strait

Directory of Open Access Journals (Sweden)

Wei-Chen Tseng

2018-04-01

Full Text Available The meteorological mast (met mast for the Taiwan Power Company’s offshore wind farm is located in Taiwan Strait near Changhua County. The p–y curve method recommended in the current offshore foundation design codes does not account for the local scour around the pile foundation; it overestimates the lateral pile deformation and underestimates the foundation stiffness. This paper presents a method to correct the initial modulus of subgrade reaction and modify the ultimate lateral resistance caused by the local scour. The natural frequency of the met mast structure is also determined by a numerical model and verified with the measured data in situ. A comprehensive parameter study is performed to analyze the effect of scour on the dynamic responses of the met mast. Two types of foundation model, a coupled-springs foundation model and a distributed-springs foundation model, are considered in the dynamic analysis of the met mast. The results demonstrate that using a distributed-springs foundation model provides a relatively accurate estimate of the natural frequencies of the met mast structure. Furthermore, the scour exerted significant effects on certain modes of the vibration responses. The natural frequencies of the met mast structure can be reduced by approximately 14% due to scour, particularly in the horizontal bending modes. This paper also provides a preliminary strategy for structural monitoring and analysis to detect scour damage on offshore wind turbines with monopile foundations.

Flow and scour around vertical submerged structures

Indian Academy of Sciences (India)

The safety of the foundations of submerged hydraulic structures due to excessive local scour is threatened by the erosive action of the waves and currents passing around these structures. Fish and aquatic habitat is seriously affected due to the modification of the flow field caused by these submerged structures. Hence, the ...

The influence of pool geometry and induced flow patterns in rock scour by high-velocity plunging jets

OpenAIRE

Almeida Manso, Pedro Filipe de; Schleiss, Anton

2007-01-01

The dissipation of energy of flood discharges from water releasing structures of dams is often done by plunging jets diffusing in water and impacting on the riverbed downstream. The construction of expensive concrete structures for energy dissipation can be avoided but the assessment of the scour evolution is mandatory for dam safety. The scour growth rate and shape depend on the riverbed geology. The geometry of scour may influence the turbulent flow pattern in the pool, the dynamic loadings...

Movable chain jacks and winches: case study of PETROBRAS' P58/)62and ENI's Goliat

Energy Technology Data Exchange (ETDEWEB)

Grindheim, Reidar [Aker Pusnes AS, Arendal (Norway)

2012-07-01

Recently, Aker Solutions delivered a movable chain jack system to PETROBRAS's P58/P62 FPSOs and a movable windlass system to ENI's Goliat FPSO. This paper highlights the main differences between the two systems and when it is beneficial to employ movable systems. There are many parameters to consider in determining which system to use - also a traditional system involving a single winch or chain jack per mooring line may in many cases be preferred. The movable chain jack concept is designed to operate multiple mooring lines within the same cluster. A single chain jack is lifted by a skidding gantry and moved to the next mooring line and so forth. Installation and messenger chains are moved using a large sliding chain locker allowing for later offloading of the surplus chain. The movable windlass system is also designed to operate multiple mooring lines within the same cluster. However, in this case the winch is rotary and can operate via electric or hydraulic power. One of the main considerations is to move the windlass and keep the mooring lines intact without cutting them. (author)

Movable shark scales act as a passive dynamic micro-roughness to control flow separation

International Nuclear Information System (INIS)

Lang, Amy W; Bradshaw, Michael T; Smith, Jonathon A; Wheelus, Jennifer N; Motta, Philip J; Habegger, Maria L; Hueter, Robert E

2014-01-01

Shark scales on fast-swimming sharks have been shown to be movable to angles in excess of 50°, and we hypothesize that this characteristic gives this shark skin a preferred flow direction. During the onset of separation, flow reversal is initiated close to the surface. However, the movable scales would be actuated by the reversed flow thereby causing a greater resistance to any further flow reversal and this mechanism would disrupt the process leading to eventual flow separation. Here we report for the first time experimental evidence of the separation control capability of real shark skin through water tunnel testing. Using skin samples from a shortfin mako Isurus oxyrinchus, we tested a pectoral fin and flank skin attached to a NACA 4412 hydrofoil and separation control was observed in the presence of movable shark scales under certain conditions in both cases. We hypothesize that the scales provide a passive, flow-actuated mechanism acting as a dynamic micro-roughness to control flow separation. (paper)

Two-phase flow simulation of scour around a cylindrical pile

Science.gov (United States)

Nagel, T.; Chauchat, J.; Bonamy, C.; Liu, X.; Cheng, Z.; Hsu, T. J.

2017-12-01

Scour around structures is a major engineering issue that requires a detailed description of the flow field but also a consistent description of sediment transport processes that could not only be related to bed shear stress, like Shields parameter based sediment transport formula. In order to address this issue we used a multi-dimensional two-phase flow solver, sedFoam-2.0 (Chauchat et al., GMD 2017) implemented under the open-source CFD toolbox OpenFoam. Three-dimensional simulations have been performed on Roulund et al. (JFM 2005) configurations for clear-water and live bed cases. The k-omega model from Wilcox (AIAA Journal 2006) is used for the turbulent stress and the granular rheology μ(I) is used for the granular stress in the live bed case. The hydrodynamic is validated on the clear water case and the numerical results obtained for the live bed case provide a proof of concept that two-phase flow model is applicable to such problem with quantitative results for the prediction of scour depth upstream and downstream the cylinder at short timescales, up to 300s. Analyzing the simulation results in term of classical dimensionless sediment transport flux versus Shields parameter allows to get more insight into the fine scale sediment transport mechanisms involved in the scour process.

Scour Monitoring System for Subsea Pipeline Based on Active Thermometry: Numerical and Experimental Studies

Directory of Open Access Journals (Sweden)

Jun Du

2013-01-01

Full Text Available A scour monitoring system for subsea pipeline based on active thermometry is proposed in this paper. The temperature reading of the proposed system is based on a distributed Brillouin optical fiber sensing technique. A thermal cable acts as the main component of the system, which consists of a heating belt, armored optical fibers and heat-shrinkable tubes which run parallel to the pipeline. The scour-induced free span can be monitored through different heat transfer behaviors of in-water and in-sediment scenarios during heating and cooling processes. Two sets of experiments, including exposing different lengths of the upper surface of the pipeline to water and creating free spans of various lengths, were carried out in laboratory. In both cases, the scour condition was immediately detected by the proposed monitoring system, which confirmed the system is robust and very sensitive. Numerical study of the method was also investigated by using the finite element method (FEM with ANSYS, resulting in reasonable agreement with the test data. This brand new system provides a promising, low cost, highly precise and flexible approach for scour monitoring of subsea pipelines.

Level II scour analysis for Bridge 8 (BARTTH00020008) on Town Highway 2, crossing Roaring Brook, Barton, Vermont

Science.gov (United States)

Boehmler, Erick M.; Ivanoff, Michael A.

1996-01-01

zero degrees. A scour hole 2.5 ft deeper than the mean thalweg depth was observed near mid-channel 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 left upstream and downstream roadway embankments. 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).

Flow under standing waves Part 2. Scour and deposition in front of breakwaters

DEFF Research Database (Denmark)

Gislason, Kjartan; Fredsøe, Jørgen; Sumer, B. Mutlu

2009-01-01

and routines for, updating the computational mesh based on the mass balance of sediment. Laboratory experiments of scour also were conducted in a wave flume to obtain data for model verification. Both in the numerical simulations and in the laboratory experiment, two kinds of breakwaters were used: A vertical......A 3-D general purpose Navier-Stokes solver was used to calculate the 2-D flow in front of the breakwater. The k-omega, SST (shear-stress transport) model was selected as the turbulence model. The morphologic model of the present code couples the flow solution with a sediment transport description......-wall breakwater; and a sloping-wall breakwater (Slope: 1:1.5). Numerically obtained scour-deposition profiles were compared with the experiments. The numerical results show that the equilibrium scour depth normalized by the wave height decreases with increasing water-depth-to-wave-length ratio. Although...

Live-bed scour experiments with 45 wing-wall abutments

Indian Academy of Sciences (India)

construction cost. ∗. For correspondence ... was connected to the water supply system in the laboratory. A sediment trap was ..... scour conditions, the factor, Kh accounting approaching flow depth, may be taken equal to 1. Envelope curve in ...

Bridge scour monitoring technologies : development of evaluation and selection protocols for application on river bridges in Minnesota.

Science.gov (United States)

2010-03-01

Bridge failure or loss of structural integrity can result from scour of riverbed sediment near bridge abutments or : piers during high-flow events in rivers. In the past 20 years, several methods of monitoring bridge scour have been : developed spann...

Development of movable mask system to cope with high beam current

International Nuclear Information System (INIS)

Suetsugu, Y.; Shibata, K.; Sanami, T.; Kageyama, T.; Takeuchi, Y.

2003-01-01

The KEK B factory (KEKB), a high current electron-positron collider, has a movable mask (or collimator) system to reduce the background noise in the BELLE detector coming from spent particles. The early movable masks, however, had severe problems of heating, arcing, and vacuum leaks over the stored beam current of several hundred mA. The cause is intense trapped higher order modes (HOMs) excited at the mask head, where the cross section of the beam chamber changed drastically. The mask head, made of copper-tungsten alloy or pure copper, was frequently damaged by hitting of the high energy beam at the same time. Since the problems of the mask were revealed, several kinds of improved masks have been designed employing rf technologies in dealing with the HOM and installed to the ring step by step. Much progress has come from adopting a trapped-mode free structure, where the mask was a bent chamber itself. Recently the further improved mask with a reduced HOM design or HOM dampers was developed to suppress the heating of vacuum components near the mask due to the HOM traveling from the mask. To avoid damage to the mask head, on the other hand, a titanium mask head was tried. The latest masks are working as expected now at the stored beam current of 1.5 A. Presented are the problems and experiences on the movable mask system for the KEKB, which are characteristic of and common in a high intensity accelerator

Entangling movable mirrors in a double cavity system

DEFF Research Database (Denmark)

Pinard, Michel; Dantan, Aurelien Romain; Vitali, David

2005-01-01

We propose a double-cavity set-up capable of generating a stationary entangled state of two movable mirrors at cryogenic temperatures. The scheme is based on the optimal transfer of squeezing of input optical fields to mechanical vibrational modes of the mirrors, realized by the radiation pressure...... of the intracavity light. We show that the presence of macroscopic entanglement can be demonstrated by an appropriate readout of the output light of the two cavities....

The link between Movability Number and Incipient Motion in river ...

African Journals Online (AJOL)

This allowed for a firmer definition of Incipient Motion as well as a new bedload transportation equation. Additional laboratory experimentation for Particle Reynolds number over the range 0.12-486 facilitated the improved prediction of Incipient Motion from a plot of the critical Movability Number vs. Particle Reynolds number ...

Surface-geophysical techniques used to detect existing and infilled scour holes near bridge piers

Science.gov (United States)

Placzek, Gary; Haeni, F.P.

1995-01-01

Surface-geophysical techniques were used with a position-recording system to study riverbed scour near bridge piers. From May 1989 to May 1993. Fathometers, fixed- and swept-frequency con- tinuous seismic-reflection profiling (CSP) systems, and a ground-penetrating radar (GPR) system were used with a laser-positioning system to measure the depth and extent of existing and infilled scour holes near bridge piers. Equipment was purchased commercially and modified when necessary to interface the components and (or) to improve their performance. Three 200-kHz black-and-white chart- recording Fathometers produced profiles of the riverbed that included existing scour holes and exposed pier footings. The Fathometers were used in conjunction with other geophysical techniques to help interpret the geophysical data. A 20-kHz color Fathometer delineated scour-hole geometry and, in some cases, the thickness of fill material in the hole. The signal provided subbottom information as deep as 10 ft in fine-grained materials and resolved layers of fill material as thin as 1 foot thick. Fixed-frequency and swept-frequency CSP systems were evaluated. The fixed-frequency system used a 3.5-, 7.0-, or 14-kHz signal. The 3.5-kHz signal pene- trated up to 50 ft of fine-grained material and resolved layers as thin as 2.5-ft thick. The 14-kHz signal penetrated up to 20 ft of fine-grained material and resolved layers as thin as 1-ft thick. The swept-frequency systems used a signal that swept from 2- to 16-kHz. With this system, up to 50 ft of penetration was achieved, and fill material as thin as 1 ft was resolved. Scour-hole geometry, exposed pier footings, and fill thickness in scour holes were detected with both CSP systems. The GPR system used an 80-, 100-, or 300-megahertz signal. The technique produced records in water up to 15 ft deep that had a specific conductance less than 200x11ms/cm. The 100-MHz signal penetrated up to 40 ft of resistive granular material and resolved layers as

Live-bed scour experiments with 45° wing-wall abutments

Indian Academy of Sciences (India)

Live-bed scour experiments with 45° wing-wall abutments ... Department of Civil Engineering, Silchar Polytechnic, Silchar 788 010, India; Department of Civil ... Manuscript received: 19 December 2012; Manuscript revised: 13 November 2013 ...

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

Science.gov (United States)

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.

River-bed erosion due to changing boundary conditions: performance of a protective measure

Directory of Open Access Journals (Sweden)

D. Termini

2014-09-01

Full Text Available Due to the introduction of man-made sediment barriers along a river, the amount of sediment load entering the downstream river reach is different to that leaving the reach, and erosion processes occur downstream of the barrier itself. Designers are often required to take into account the scouring process and to include adequate protective measures against the local scour. This paper addresses the performance of bio-engineering protective measures against the erosion process. In particular, a green carpet, realized with real flexible vegetation, has been used as the protective measure against erosion processes downstream of a rigid bed. Analyses are based on experimental work carried out in a straight channel constructed at the laboratory of the Dipartimento di Ingegneria Civile, Ambientale, Aereospaziale, dei Materiali, Palermo University (Italy.

Numerical simulation of scouring-deposition variations caused by rainfall-induced landslides in the upstream of Zengwun River, Taiwan

Science.gov (United States)

Lee, Ming-Hsi; Liao, Yi-Wen; Tsai, Kuang-Jung

2017-04-01

In recent years, the increasing sediment disasters of severe rainfall-induced landslides on human lives and lifeline facilities worldwide have advanced the necessity to find out both economically acceptable and useful techniques to predict the occurrence and destructive power of the disasters. In August 2009, Typhoon Morakot brought a large amount of rainfall with both high intensity and long duration to a vast area of Taiwan. Unfortunately, this resulted in a catastrophic landslide in watershed of Zengwun-River reservoir, southern Taiwan. Meanwhile, large amounts of landslides were formed in the upstream of Zengwun River. The major scope of this study is to apply numerical model to simulate the scouring-deposition variations caused by rainfall-induced landslides that occurred in the upstream of Zengwun River during Typhoon Morakot. This study proposed the relation diagrams of the intermediate diameter (d50), recurrence interval (T) and scouring-deposition depth (D), and applied the diagrams to understand the impacts of the scouring-deposition variations on the structures for water and soil conservation and their measurements. Based on the simulation of scouring-deposition variation at the Da-Bu dam and Da-Bang dam, this study also discussed the scouring-deposition variations of different sections under different scenarios (including flow rate, intermediate diameters and structures). In summary, the result suggested that the diagrams of the intermediate diameter, recurrence interval and scouring-deposition depth could be used as the reference for designing the check dams, ground sills and lateral constructions.

Numerical Modeling of Scour at the Head of a Vertical-Wall Breakwater in Waves

Science.gov (United States)

Baykal, C.; Balcı, H. B.; Sumer, B. M.; Fuhrman, D. R.

2017-12-01

This study presents a 3D numerical modeling study on the flow and scour at the head of a vertical-wall breakwater in regular waves. The numerical model utilized in the study is based on that given by Jacobsen (2011). The present model has been applied successfully to the scour and backfilling beneath submarine pipelines by Fuhrman et al. (2014), and around a vertical cylindrical pile mounted on a horizontal plane sediment bed by Baykal et al. (2015, 2017). The model is composed of two main modules. The first module is the hydrodynamic model where Reynolds Averaged Navier Stokes (RANS) equations are solved with a k-ω turbulence closure. The second module is the morphologic model which comprises five sub-modules, namely; bed load, suspended load, sand slide, bed evolution and 3D mesh motion. The model is constructed in open-source CFD toolbox OpenFOAM. In this study, the model is applied to experimental data sets of Sumer and Fredsoe (1997) on the scour around a vertical-wall breakwater with a circular round head. Here, it is given the preliminary results of bed evolution of Test-8 of Sumer and Fredsoe (1997) in which a vertical-wall breakwater head with a width of B=140 mm is subjected to oscillatory flow with Tw=2.0 s and maximum orbital velocity at the bed Um=22cm/s, resulting in a Keulegan-Carpenter number, KC=3.14, close to KC experienced in real-life situations (KC = O(1)). The grain size is d=0.17 mm. The Shields parameter in the test case is given as θc=0.11, larger than the critical value for the initiation of motion implying that the scour is in the live-bed regime. The computational domain used in the simulations has the following dimensions: Length, l=40B, Width, w=20B, and Height, h=2B. The total number of cells is O(105) in the simulations. The scoured bed profile computed at the end of 3 periods of oscillatory flow of Test-8 is given in the figure below. The color scale in the figure is given for the ratio of bed elevation to the width of breakwater

Data base for assessment of streambed scour and channel instability at selected bridges in Indiana, 1991-95

Science.gov (United States)

Hopkins, Mark S.; Robinson, Bret A.

1997-01-01

The U.S. Geological Survey, in cooperation with the Indiana Department of Transportation, has collected data at 5,587 bridges in Indiana built with federal aid. These data, which can be useful for assessing Streambed scour and channel instability, are maintained in a computerized data base at the U.S. Geological Survey in Indianapolis, Indiana. The data elements are grouped under one of five headings: General Site Characteristics, Observed and Calculated Scour Characteristics, Bridge Characteristics, Stream Characteristics, and Debris Characteristics. The description of the data in each group includes the element name; examples of the data from bridge number 89-54 crossing Lick Creek in Wayne County, Indiana; and a brief description of each element. The data already have been used in Indiana to produce an observed-scour index and a potential-scour index and may be useful in other applications as well. For computers with Internet access, the files containing the data for all 5,587 sites are available for downloading at the following URL:

Monitoring bridge scour using fiber optic sensors : research project capsule.

Science.gov (United States)

2009-03-01

The interstate highway network is an : important national asset. Bridges : constituting critical nodes within : transportation networks are the : backbone of the transportation : infrastructure. It is well known that : scour is one of the major cours...

Study of technical and economical feasibility for implementation of a movable unit for treatment of industrial effluents with electron beam

International Nuclear Information System (INIS)

Rela, Carolina Sciamarelli

2006-01-01

The treatment of industrial effluents is a practice that is disseminating in accelerated rhythm, of contributing to reinforce the public image, through the combat of the pollution, it brings economical advantages allowing the companies the reuse of the treated water in their own processes. The liquid effluent treatment technique studied in the present work is the one that uses the chemical oxidation/reduction standing out the use of the electron beam (e.b.) radiation. This technique uses an advanced oxidation process, generating radicals highly reagents that provoke the oxidation, reduction, dissociation and degradation in composed organic and exercising lethal effect in general in the microorganisms and parasites. In this work a conceptual and basic project of a movable unit of effluents treatment using electron beam radiation process was developed, in order that the unit moves until the treatment point, where the effluent is produced, facilitating the logistics. A technical and economical feasibility study was also elaborated allowing data on the capacity and cost of effluents processing to consolidate the values of the necessary investments to be presented to foundations organs for the construction of a movable unit. The results of the studies demonstrated that it is technically viable attending the pertinent legislation of Brazil, in the aspects of Radiation Protection and transport limit capacity. The unitary cost of the e.b. radiation processing in the movable unit was shown more expensive than in the fixed unit, the reason is the decrease of the efficiency of the interaction of the incident electrons in the effluent, due to the reduction of electron energy operation time of the unit. (author)

Using a Modified Lane’s Relation in Local Bed Scouring Studies in the Laboratory Channel

Directory of Open Access Journals (Sweden)

Marta Kiraga

2016-01-01

Full Text Available Numerous approaches to local scour forming studies have been developed. This paper presents different scientific approaches to the scour phenomenon using Lane’s relation [1] in its modified form during laboratory studies. The original Lane’s relation is applicable in dynamic balance conditions in alluvial rivers context, and it is not an equation, but a qualitative expression which cannot be directly used to estimate the influence of a change in one parameter on the magnitude of others. Lane's relation, despite its qualitative and simplified character, serves well to describe the nature of the process of forming alluvial stream channels, while modified relation allows transforming it into an equation for laboratory studies of local scour forming in prearranged clear-water equilibrium conditions and gives a new opportunity for this principle application.

Munition Burial by Local Scour and Sandwaves: large-scale laboratory experiments

Science.gov (United States)

Garcia, M. H.

2017-12-01

Our effort has been the direct observation and monitoring of the burial process of munitions induced by the combined action of waves, currents and pure oscillatory flows. The experimental conditions have made it possible to observe the burial process due to both local scour around model munitions as well as the passage of sandwaves. One experimental facility is the Large Oscillating Water Sediment Tunnel (LOWST) constructed with DURIP support. LOWST can reproduce field-like conditions near the sea bed. The second facility is a multipurpose wave-current flume which is 4 feet (1.20 m) deep, 6 feet (1.8 m) wide, and 161 feet (49.2 m) long. More than two hundred experiments were carried out in the wave-current flume. The main task completed within this effort has been the characterization of the burial process induced by local scour as well in the presence of dynamic sandwaves with superimposed ripples. It is found that the burial of a finite-length model munition (cylinder) is determined by local scour around the cylinder and by a more global process associated with the formation and evolution of sandwaves having superimposed ripples on them. Depending on the ratio of the amplitude of these features and the body's diameter (D), a model munition can progressively get partially or totally buried as such bedforms migrate. Analysis of the experimental data indicates that existing semi-empirical formulae for prediction of equilibrium-burial-depth, geometry of the scour hole around a cylinder, and time-scales developed for pipelines are not suitable for the case of a cylinder of finite length. Relative burial depth (Bd / D) is found to be mainly a function of two parameters. One is the Keulegan-Carpenter number, KC, and the Shields parameter, θ. Munition burial under either waves or combined flow, is influenced by two different processes. One is related to the local scour around the object, which takes place within the first few hundred minutes of flow action (i.e. short

Assessment of the NCHRP abutment scour prediction equations with laboratory and field data

Science.gov (United States)

Benedict, Stephen T.

2014-01-01

The U.S. Geological Survey, in coopeation with nthe National Cooperative Highway Research Program (NCHRP) is assessing the performance of several abutment-scour predcition equations developed in NCHRP Project 24-15(2) and NCHRP Project 24-20. To accomplish this assssment, 516 laboratory and 329 fiels measurements of abutment scor were complied from selected sources and applied tto the new equations. Results will be used to identify stregths, weaknesses, and limitations of the NCHRP abutment scour equations, providing practical insights for applying the equations. This paper presents some prelimiray findings from the investigation.

Numerical calculation of backfilling of scour holes

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Baykal, Cüneyt; Fuhrman, David R.

2014-01-01

A fully-coupled hydrodynamic and morphologic CFD model is presented for simulating backfilling processes around structures. The hydrodynamic model is based on Reynolds-averaged Navier-Stokes equations, coupled with two-equation k-ω turbulence closure. The sediment transport model consists of sepa...... of structures: piles, and pipelines. Initial scour holes are generated by the same model. The numerical results appear to be in accord with the existing experimental information....

Predicting scour beneath subsea pipelines from existing small free span depths under steady currents

Directory of Open Access Journals (Sweden)

Jun Y. Lee

2017-06-01

Full Text Available An equation was developed to predict current-induced scour beneath subsea pipelines in areas with small span depths, S. Current equations for scour prediction are only applicable to partially buried pipelines. The existence of small span depths (i.e. S/D < 0.3 are of concern because the capacity for scour is higher at smaller span depths. Furthermore, it is impractical to perform rectification works, such as installing grout bags, under a pipeline with a small S/D. Full-scale two-dimensional computational fluid dynamics (CFD simulations were performed using the Reynolds-averaged Navier–Stokes approach and the Shear stress transport k–ω turbulence model. To predict the occurrence of scour, the computed maximum bed shear stress beneath the pipe was converted to the dimensionless Shields parameter, and compared with the critical Shields parameter based on the mean sediment grain size. The numerical setup was verified, and a good agreement was found between model-scale CFD data and experimental data. Field data were obtained to determine the mean grain size, far field current velocity and to measure the span depths along the surveyed pipe length. A trend line equation was fitted to the full-scale CFD data, whereby the maximum Shields parameter beneath the pipe can be calculated based on the undisturbed Shields parameter and S/D.

Neuro-fuzzy GMDH based particle swarm optimization for prediction of scour depth at downstream of grade control structures

Directory of Open Access Journals (Sweden)

Mohammad Najafzadeh

2015-03-01

Full Text Available In the present study, neuro-fuzzy based-group method of data handling (NF-GMDH as an adaptive learning network was utilized to predict the maximum scour depth at the downstream of grade-control structures. The NF-GMDH network was developed using particle swarm optimization (PSO. Effective parameters on the scour depth include sediment size, geometry of weir, and flow characteristics in the upstream and downstream of structure. Training and testing of performances were carried out using non-dimensional variables. Datasets were divided into three series of dataset (DS. The testing results of performances were compared with the gene-expression programming (GEP, evolutionary polynomial regression (EPR model, and conventional techniques. The NF-GMDH-PSO network produced lower error of the scour depth prediction than those obtained using the other models. Also, the effective input parameter on the maximum scour depth was determined through a sensitivity analysis.

Time scale of scour around a pile in combined waves and current

DEFF Research Database (Denmark)

Petersen, Thor Ugelvig; Sumer, B. Mutlu; Fredsøe, Jørgen

The time scale of the scour process around a circular vertical pile is studied in combined waves and current. A series of tests were carried out in a flume with pile diameters 40 mm and 75 mm, in both steady current, waves and combined waves and current. In the combined wave and current flow regime...... the waves and the current were co-directional. All the tests were conducted in the live bed regime. The time scale of scour in combined waves and current is governed by three parameters, namely the current-velocity-to-wave-velocity ratio (Ucw), the Keulegan–Carpenter number (KC) and Shields parameter (Θw...

Rotor for processing liquids using movable capillary tubes

Science.gov (United States)

Johnson, W.F.; Burtis, C.A.; Walker, W.A.

1987-07-17

A rotor assembly for processing liquids, especially whole blood samples, is disclosed. The assembly includes apparatus for separating non-liquid components of whole blood samples from liquid components, apparatus for diluting the separated liquid component with a diluent and apparatus for transferring the diluted sample to an external apparatus for analysis. The rotor assembly employs several movable capillary tubes to handle the sample and diluents. A method for using the rotor assembly to process liquids is also described. 5 figs.

Scour at the head of a vertical-wall breakwater

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Fredsøe, Jørgen

1997-01-01

This paper presents the results of an experimental investigation on the near-bed flow patterns, the bed shear stress amplification and scour around the head of a vertical-wall breakwater, using regular waves. The Keulegan-Carpenter number (KC), based on the diameter of the breakwater head, is found...

Bridge scour countermeasure assessments at select bridges in the United States, 2014–16

Science.gov (United States)

Dudunake, Taylor J.; Huizinga, Richard J.; Fosness, Ryan L.

2017-05-23

In 2009, the Federal Highway Administration published Hydraulic Engineering Circular No. 23 (HEC-23) to provide specific design and implementation guidelines for bridge scour and stream instability countermeasures. However, the effectiveness of countermeasures implemented over the past decade following those guidelines has not been evaluated. Therefore, in 2013, the U.S. Geological Survey, in cooperation with the Federal Highway Administration, began a study to assess the current condition of bridge-scour countermeasures at selected sites to evaluate their effectiveness. Bridge-scour countermeasures were assessed during 2014-2016. Site assessments included reviewing countermeasure design plans, summarizing the peak and daily streamflow history, and assessments at each site. Each site survey included a photo log summary, field form, and topographic and bathymetric geospatial data and metadata. This report documents the study area and site-selection criteria, explains the survey methods used to evaluate the condition of countermeasures, and presents the complete documentation for each countermeasure assessment.

Experimental Study of the Development of Scour and Backfilling

DEFF Research Database (Denmark)

Hartvig, Peres Akrawi; Thomsen, Jess Mccann; Frigaard, Peter

2010-01-01

This paper deals with the development of scour holes in time and space around individual offshore monopiles. It is based on physical flume tests of a model-scale pile subjected to current and/or irregular water waves. The main focus is on backfilling, i.e. the wave-induced or current...

Monitoring Streambed Scour/Deposition Under Nonideal Temperature Signal and Flood Conditions

Science.gov (United States)

DeWeese, Timothy; Tonina, Daniele; Luce, Charles

2017-12-01

Streambed erosion and deposition are fundamental geomorphic processes in riverbeds, and monitoring their evolution is important for ecological system management and in-stream infrastructure stability. Previous research showed proof of concept that analysis of paired temperature signals of stream and pore waters can simultaneously provide monitoring scour and deposition, stream sediment thermal regime, and seepage velocity information. However, it did not address challenges often associated with natural systems, including nonideal temperature variations (low-amplitude, nonsinusoidal signal, and vertical thermal gradients) and natural flooding conditions on monitoring scour and deposition processes over time. Here we addressed this knowledge gap by testing the proposed thermal scour-deposition chain (TSDC) methodology, with laboratory experiments to test the impact of nonideal temperature signals under a range of seepage velocities and with a field application during a pulse flood. Both analyses showed excellent match between surveyed and temperature-derived bed elevation changes even under very low temperature signal amplitudes (less than 1°C), nonideal signal shape (sawtooth shape), and strong and changing vertical thermal gradients (4°C/m). Root-mean-square errors on predicting the change in streambed elevations were comparable with the median grain size of the streambed sediment. Future research should focus on improved techniques for temperature signal phase and amplitude extractions, as well as TSDC applications over long periods spanning entire hydrographs.

Indian practice on estimation of scour around bridge piers—A ...

Indian Academy of Sciences (India)

are illustrated in this paper using examples. The methods .... moisture and drainage conditions prevailing in cohesive soils, the scour in them can be less, equal or .... Hence, it would be wrong to take K = 2·0, when DLq is used as stipulated.

Quantum theory of shuttling instability in a movable quantum dot array

DEFF Research Database (Denmark)

Donarini, Andrea; Novotny, Tomas; Jauho, Antti-Pekka

2004-01-01

We study the shuttling instability in an array of three quantum dots the central one of which is movable. We extend the results by Armour and MacKinnon on this problem to a broader parameter regime. The results obtained by an efficient numerical method are interpreted directly using the Wigner...

Spatial variability of the wave bottom boundary layer over movable rippled beds

NARCIS (Netherlands)

Rodriguez-Abudo, S.; Foster, D.L.; Henriquez, M.

2013-01-01

Observations of the spatially dependent velocity field over movable bed forms subjected to slightly skewed and asymmetric regular wave forcing were collected. The dynamics between the ripple elements is dominated by coherent vortices, characterized by the swirling strength, and evidenced in the

Numerical Investigation of the Influence of Water Jumping on the Local Scour beneath a Pipeline under Steady Flow

Directory of Open Access Journals (Sweden)

Fei Fan

2017-08-01

Full Text Available Rigid-lid approximation is usually used to replace the free surface in scour simulation. The influence of the rigid lid assumption on the prediction precision of scour hole in steady flow is studied in this paper. Firstly, a local scour model was constructed based on the open sources Computational Fluid Dynamics (CFD model OpenFOAM, where both the bed load and suspended load were considered. In the present model, the bed shear stress was calculated by the Newton shear stress formula, instead of the traditional calculation method with the assumption that the flow velocity in vertical direction complies with a logarithmic distribution. The Volume of Fluid (VOF method was used to capture the free surface and a moving-mesh method was used to track the change of bed surface. Then, several experiments were chosen to validate the model, and the modeling results fitted well with the measured data. Lastly, the effect of the rigid lid assumption on surface elevation, bed shear stress and the profile of the scour hole in steady flow are studied. The result shows that the surface elevation suffers a drop above the pipeline, and the difference of surface elevation between the upstream and downstream increases with decreasing dimensionless depth. Compared with the free surface condition, the bed shear stress and scour hole depth computed with the rigid lid approximation were underestimated.

Computational Modeling of Hydrodynamics and Scour around Underwater Munitions

Science.gov (United States)

Liu, X.; Xu, Y.

2017-12-01

Munitions deposited in water bodies are a big threat to human health, safety, and environment. It is thus imperative to predict the motion and the resting status of the underwater munitions. A multitude of physical processes are involved, which include turbulent flows, sediment transport, granular material mechanics, 6 degree-of-freedom motion of the munition, and potential liquefaction. A clear understanding of this unique physical setting is currently lacking. Consequently, it is extremely hard to make reliable predictions. In this work, we present the computational modeling of two importance processes, i.e., hydrodynamics and scour, around munition objects. Other physical processes are also considered in our comprehensive model. However, they are not shown in this talk. To properly model the dynamics of the deforming bed and the motion of the object, an immersed boundary method is implemented in the open source CFD package OpenFOAM. Fixed bed and scour cases are simulated and compared with laboratory experiments. The future work of this project will implement the coupling between all the physical processes.

Hydraulic survey and scour assessment of Bridge 524, Tanana River at Big Delta, Alaska

Science.gov (United States)

Heinrichs, Thomas A.; Langley, Dustin E.; Burrows, Robert L.; Conaway, Jeffrey S.

2007-01-01

Bathymetric and hydraulic data were collected August 26–28, 1996, on the Tanana River at Big Delta, Alaska, at the Richardson Highway bridge and Trans-Alaska Pipeline crossing. Erosion along the right (north) bank of the river between the bridge and the pipeline crossing prompted the data collection. A water-surface profile hydraulic model for the 100- and 500-year recurrence-interval floods was developed using surveyed information. The Delta River enters the Tanana immediately downstream of the highway bridge, causing backwater that extends upstream of the bridge. Four scenarios were considered to simulate the influence of the backwater on flow through the bridge. Contraction and pier scour were computed from model results. Computed values of pier scour were large, but the scour during a flood may actually be less because of mitigating factors. No bank erosion was observed at the time of the survey, a low-flow period. Erosion is likely to occur during intermediate or high flows, but the actual erosion processes are unknown at this time.

Comparison of Scour and Flow Characteristics Around Circular and Oblong Bridge Piers in Seepage Affected Alluvial Channels

Science.gov (United States)

Chavan, Rutuja; Venkataramana, B.; Acharya, Pratik; Kumar, Bimlesh

2018-06-01

The present study examines scour geometry and turbulent flow characteristics around circular and oblong piers in alluvial channel with downward seepage. Experiments were conducted in plane sand bed of non-uniform sand under no seepage, 10% seepage and 15% seepage conditions. Scour depth at oblong pier is significantly lesser than the scour depth at circular one. However, the scour depth at both piers reduces with downward seepage. The measurements show that the velocity and Reynolds stresses are negative near the bed at upstream of piers where the strong reversal occurs. At downstream of oblong pier near the free surface, velocity and Reynolds stresses are less positive; whereas, they are negative at downstream of circular pier. The streamline shape of oblong pier leads to reduce the strength of wake vortices and consequently reversal flow at downstream of pier. With application of downward seepage turbulent kinetic energy is decreasing. The results show that the wake vortices at oblong pier are weaker than the wake vortices at circular pier. The strength of wake vortices diminishes with downward seepage. The Strouhal number is lesser for oblong pier and decreases with downward seepage for both oblong and circular piers.

Level II scour analysis for Bridge 37 (TOWNTH00290037) on Town Highway 29, crossing Mill Brook, Townshend, Vermont

Science.gov (United States)

Burns, R.L.; Medalie, Laura

1998-01-01

This report provides the results of a detailed Level II analysis of scour potential at structure TOWNTH00290037 on Town Highway 29 crossing Mill Brook, Townshend, 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.

Level II scour analysis for Bridge 8, (MANCTH00060008) on Town Highway 6, crossing Bourn Brook, Manchester, Vermont

Science.gov (United States)

Burns, Ronda L.; Hammond, Robert E.

1997-01-01

This report provides the results of a detailed Level II analysis of scour potential at structure MANCTH00060008 on Town Highway 6 crossing Bourn 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.

Level II scour analysis for Bridge 30, (HUNTTH00220030), on Town Highway 22, crossing Brush Brook, Huntington, Vermont

Science.gov (United States)

Burns, Ronda L.

1997-01-01

This report provides the results of a detailed Level II analysis of scour potential at structure HUNTTH00220030 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.

Level II scour analysis for brigde 5 (STOCTH00360005) on Town Highway 36, crossing Stony Brook, Stockridge, Vermont

Science.gov (United States)

Striker, Lora K.; Weber, Matthew A.

1998-01-01

This report provides the results of a detailed Level II analysis of scour potential at structure STOCTH00360005 on Town Highway 36 crossing Stony Brook, Stockbridge, 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.

Level II scour analysis for Bridge 8 (ATHETH00090008) on Town Highway 9, crossing Bull Creek, Athens, Vermont

Science.gov (United States)

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 ATHETH00090008 on Town Highway 9 crossing Bull Creek in Athens, 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.

Level II scour analysis for Bridge 16, (NEWBTH00500016) on Town Highway 50, crossing Halls Brook, Newbury, Vermont

Science.gov (United States)

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 NEWBTH00500016 on Town Highway 50 crossing Halls Brook, Newbury, 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.

Bi-objective analysis of water-sediment regulation for channel scouring and delta maintenance: A study of the lower Yellow River

Science.gov (United States)

Kong, D.; Miao, C.; Duan, Q.

2016-12-01

Long-term hydrological data and remotely-sensed satellite images were used to analyze the effects of the water-sediment regulation scheme (WSRS) implemented in the lower Yellow River (LYR), China, between 1983 and 2013. The WSRS aimed to control channel scouring in the LYR and maintain the Yellow River Delta (YRD). Channel erosion in the LYR has primarily depended on the incoming sediment concentration at Xiaolangdi, where the concentration must be lower than approximately 9.17 × 10-3 t m-3 to avoid rising of the riverbed. In 1996, an artificial diversion altered the evolution of the YRD. To maintain delta equilibrium, an average sediment load of about 441 × 106 t year-1 was required before 1996, after which this value decreased to 167 × 106 t year-1. We provide a preliminary estimate of the incoming water and sediment conditions required at the Xiaolangdi station to guarantee both LYR channel scouring and maintenance of the YRD. Our results show that it is feasible to transport sediment originally deposited in the LYR to the river mouth to maintain the delta, which is of great significance for the future management and environmental protection of the LYR.

Evaluation of scour potential of cohesive soils : final report, August 2009.

Science.gov (United States)

2009-08-01

Prediction of scour at bridge river crossings is an evolving process. Hydraulic models to estimate water velocity and, therefore, the shear stresses that erode soil are reasonably well developed. The weak link remains methods for estimating soil erod...

Numerical Analysis Study of Sarawak Barrage River Bed Erosion and Scouring by Using Smooth Particle Hydrodynamic (SPH)

Science.gov (United States)

Zainol, M. R. R. M. A.; Kamaruddin, M. A.; Zawawi, M. H.; Wahab, K. A.

2017-11-01

Smooth Particle Hydrodynamic is the three-dimensional (3D) model. In this research work, three cases and one validation have been simulate using DualSPHysics. Study area of this research work was at Sarawak Barrage. The cases have different water level at the downstream. This study actually to simulate riverbed erosion and scouring properties by using multi-phases cases which use sand as sediment and water. The velocity and the scouring profile have been recorded as the result and shown in the result chapter. The result of the validation is acceptable where the scouring profile and the velocity were slightly different between laboratory experiment and simulation. Hence, it can be concluded that the simulation by using SPH can be used as the alternative to simulate the real cases.

Smart Rocks for Bridge Scour Monitoring: Design and Localization Using Electromagnetic Techniques and Embedded Orientation Sensors

Science.gov (United States)

Radchenko, Andro

River bridge scour is an erosion process in which flowing water removes sediment materials (such as sand, rocks) from a bridge foundation, river beds and banks. As a result, the level of the river bed near a bridge pier is lowering such that the bridge foundation stability can be compromised, and the bridge can collapse. The scour is a dynamic process, which can accelerate rapidly during a flood event. Thus, regular monitoring of the scour progress is necessary to be performed at most river bridges. Present techniques are usually expensive, require large man/hour efforts, and often lack the real-time monitoring capabilities. In this dissertation a new method--'Smart Rocks Network for bridge scour monitoring' is introduced. The method is based on distributed wireless sensors embedded in ground underwater nearby the bridge pillars. The sensor nodes are unconstrained in movement, are equipped with years-lasting batteries and intelligent custom designed electronics, which minimizes power consumption during operation and communication. The electronic part consists of a microcontroller, communication interfaces, orientation and environment sensors (such as are accelerometer, magnetometer, temperature and pressure sensors), supporting power supplies and circuitries. Embedded in the soil nearby a bridge pillar the Smart Rocks can move/drift together with the sediments, and act as the free agent probes transmitting the unique signature signals to the base-station monitors. Individual movement of a Smart Rock can be remotely detected processing the orientation sensors reading. This can give an indication of the on-going scour progress, and set a flag for the on-site inspection. The map of the deployed Smart Rocks Network can be obtained utilizing the custom developed in-network communication protocol with signals intensity (RSSI) analysis. Particle Swarm Optimization (PSO) is applied for map reconstruction. Analysis of the map can provide detailed insight into the scour

Reduction of scour around bridge piers using a modified method for vortex reduction

Directory of Open Access Journals (Sweden)

Entesar A.S. EL-Ghorab

2013-09-01

Full Text Available The current study presents a modified method to reduce the scour depth in front of the bridge piers. The idea of this method is based on reducing the stagnation of the flow and vortex formation in front of the pier. Therefore, the pressure difference around the pier is used for driving the flow through an arrangement of openings in front and connected to the openings along the pier’s side. A test program was planned using an experimental flume at the Hydraulics Research Institute (HRI and three hundred thirty six runs were conducted. Three different pier shapes, circular, square, and rectangular, provided with different openings arrangement and vertical spacing are tested. This method showed that the scour depth is reduced by 45% and also the volume of the scoured material is decreased up to 64%. These results were obtained using opening diameter of 20% of the pier width (w and vertical spacing equals the pier width (w. Also, a dimensionless regression equation was developed based on the obtained results. These findings when implemented in the field can easily safeguard the bridge piers and dramatically reduce the maintenance efforts and costs as well as improve the hydraulic performance of the water structure.

Level II scour analysis for Bridge 16 (GROTTH00170016) on Town Highway 17, crossing the Wells River, Groton, Vermont

Science.gov (United States)

Striker, L.K.; Ivanoff, M.A.

1997-01-01

This report provides the results of a detailed Level II analysis of scour potential at structure GROTTH00170016 on Town Highway 17 crossing the Wells River, Groton, 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.

Level II scour analysis for Bridge 37, (BRNETH00740037) on Town Highway 74, crossing South Peacham Brook, Barnet, Vermont

Science.gov (United States)

Burns, Ronda L.; Severance, Timothy

1997-01-01

This report provides the results of a detailed Level II analysis of scour potential at structure BRNETH00740037 on Town Highway 74 crossing South Peacham Brook, 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.

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

Science.gov (United States)

Ayotte, Joseph D.; Boehmler, Erick M.

1996-01-01

This report provides the results of a detailed Level II analysis of scour potential at structure BARTTH00080037 on town highway 8 crossing the Willoughby River, Barton, 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

Fatigue Design and Prevention in Movable Scaffolding Systems

Directory of Open Access Journals (Sweden)

Coelho Hugo

2017-06-01

Full Text Available The Movable Scaffolding System (MSS is a heavy construction equipment used for casting situ of concrete bridge decks. In the past decades, MSSs have become increasingly complex and industrialized, enlarging its span ranges, incorporating auxiliary elevation machinery and increasing productivity. The tendency nowadays is for strong reutilization and the notion of MSS as a disposable or temporary structure is somehow reductive. The main structure of MSSs may be potentially exposed to fatigue, usually characterized by low number of cycles with significant stress amplitude. Fatigue may be prevented through adequate design; judicious selection of materials; demanding quality control and implementation of robust inspection and maintenance plans.

Fatigue Design and Prevention in Movable Scaffolding Systems

Science.gov (United States)

Coelho, Hugo; Torres, Alberto; Pacheco, Pedro; Moreira, Cristiano; Silva, Rute; Soares, José M.; Pinto, Dânia

2017-06-01

The Movable Scaffolding System (MSS) is a heavy construction equipment used for casting situ of concrete bridge decks. In the past decades, MSSs have become increasingly complex and industrialized, enlarging its span ranges, incorporating auxiliary elevation machinery and increasing productivity. The tendency nowadays is for strong reutilization and the notion of MSS as a disposable or temporary structure is somehow reductive. The main structure of MSSs may be potentially exposed to fatigue, usually characterized by low number of cycles with significant stress amplitude. Fatigue may be prevented through adequate design; judicious selection of materials; demanding quality control and implementation of robust inspection and maintenance plans.

Level II scour analysis for Bridge 81 (MARSUS00020081) on U.S. Highway 2, crossing the Winooski River, Marshfield, Vermont

Science.gov (United States)

Ivanoff, Michael A.

1997-01-01

This report provides the results of a detailed Level II analysis of scour potential at structure MARSUS00020081 on U.S. Highway 2 crossing the Winooski River, Marshfield, 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.

Influence of the Hydrograph Shape on the Scour Development

OpenAIRE

Gjunsburgs, B; Jaudzems, G; Govša, J

2010-01-01

Transport system infrastructures, namely roads, bridges, dams, and water intakes in rivers are under permanent impacts of multiple floods. To estimate their safety and stability during scour at hydraulic structure foundations, a multidisciplinary approach, which will involve the principles of hydraulics, hydrology, morphology, geology, and so on, is required. In the present study, the effects of probability, duration, sequence, and frequency of multiple floods on the safety and st...

Scale Factor Study for 1:30 Local Scour Model

Science.gov (United States)

2016-08-01

establishes the worst- case scour depth for the current bridge configuration and the proposed pier nose extension. INTRODUCTION : Extensive research has been...used in the general physical model. A flat test section, approximately 32 ft long and 34–45 ft wide, was molded to a uniform elevation . Stilling...discharge calculation from the flow uniformity checks. The water surface elevation was controlled with the adjustable lift gate at the downstream

Using a modified Lane’s relation in local bed scouring studies in aluvial bed

Directory of Open Access Journals (Sweden)

Marta Kiraga

2016-12-01

Full Text Available Numerous approaches to the local scour studies have been developed. The research aim was to verify modified Lane’s relation in scope of local scouring phenomenon basing on laboratory studies results. Original Lane’s relation [1955] is applicable in dynamic balance conditions in alluvial rivers context. Original form is not an equation, but a qualitative expression which cannot be directly used to estimate the influence of a change in one parameter on the magnitude of others. Modified version allows transforming it into equation for dynamic equilibrium conditions in steady flow assumption and gives a new opportunity to this principle application. Two physical models of laboratory channel with rectangular cross-sections and glass panels have been constructed, with totally or partially sandy bottom. Model I assumed non-continual sediment transport, because of model construction, i.e. the solid bottom transforms into sandy bottom in the intake part. Model II assumed water structure (the weir with four slots introducing into laboratory channel with solid bottom in its region, whereas the rest of channel was filled with sand above and below structure, i.e. continuity of sediment transport was assured. Results of research confirmed modified Lane’s relation usability in scope of local scouring phenomenon description in dynamic equilibrium conditions of alluvial sandy bed.

Quantum theory of shuttling instability in a movable quantum dot array

Science.gov (United States)

Donarini, Andrea; Novotný, Tomás; Jauho, Antti-Pekka

2004-04-01

We study the shuttling instability in an array of three quantum dots the central one of which is movable. We extend the results by Armour and MacKinnon on this problem to a broader parameter regime. The results obtained by an efficient numerical method are interpreted directly using the Wigner distributions. We emphasize that the instability should be viewed as a crossover phenomenon rather than a clear-cut transition.

Bridge Failure Due to Inadequate Design of Bed Protection

Science.gov (United States)

Gupta, Yogita; Kaur, Suneet; Dindorkar, Nitin

2017-12-01

The shallow foundation is generally provided on non-erodible strata or where scour depth is less. It is also preferable for low perennial flow or standing water condition. In the present case study shallow foundation is adopted for box type bridge. The total length of the bridge is 132.98 m, consisting of eight unit of RCC box. Each unit is composed of three cell box. The bottom slab of box unit is acted as raft foundation, founded 500 mm below ground level. River bed protection work is provided on both upstream and downstream side along the whole length of the bridge as it is founded above scour level. The bridge collapsed during the monsoon just after two years of service. The present paper explains the cause of failure. This study on failure of the bridge illustrates the importance of bridge inspection before and after monsoon period and importance of the timely maintenance. Standard specifications of Indian Road Congress for the river bed protection work are also included.

Upstream sediment input effects on experimental dune trough scour in sediment mixtures

NARCIS (Netherlands)

Kleinhans, M.G.

2005-01-01

Understanding causes of dune irregularity, especially dune trough scour, is important for the modeling of vertical sorting of sediment mixtures in morphological models of rivers with sediment mixtures. Sediment in dunes is generally sorted in a fining-upward manner, which affects the sediment

A study of the behaviour of and the forces in a bed protecting mattress : The falling apron

NARCIS (Netherlands)

Vrijling, J.K.; Ravenstijn, P.

2001-01-01

In many cases the bottom around a structure that is exposed to current has to be protected by a mattress. The purpose of the mattress is to protect the soil besides the structure from erosion and scour, thus preserving the strength of the foundation of the structure. Examples are the bottom

The Registration of Special Notarial Bonds under the Security by Means of Movable Property Act and the Publicity Principle: Lessons from Developments in Belgium

Directory of Open Access Journals (Sweden)

Lefa

2018-01-01

Full Text Available Many people do not own immovable property to offer as security but do have movable property which can be offered as security for the repayment of a debt. In today's world, where the costs of a motor car can exceed that of a house, the increasing value of movable things makes them popular and appropriate security objects. Under the common law pledge, delivery of the movable property from the pledgor (the debtor to the pledgee (the creditor has to take place in order for the pledgee to acquire a real security right in the property. Delivery of the property is aimed at ensuring compliance with the publicity principle. The principle of publicity entails that the existence of a real security must be known to the public. With the aim of promoting commerce, certain countries have taken the initiative in reforming their laws on pledge to allow the debtor to retain possession of the movable property that serves as security. Furthermore, technology has advanced to a level where national registration systems which can be accessed easily and at minimal cost can be established. The South African legislature enacted the Security by Means of Movable Property Act 57 of 1993 which makes provision for a pledge without possession. This Act deemed a duly registered notarial bond over specified movable property to have been delivered as if delivery had in fact taken place, thereby substituting the common law delivery requirement with registration in the Deeds Office. On 30 May 2013 the Belgian House of Representatives adopted a Belgian Pledge Act which allows for a non-possessory pledge on movable property subject to registration in a newly created public register called the Electronic Pledge Register. This article therefore examines the efficacy of the registration system of special notarial bonds in South African law and whether this form of registration complies with the publicity principle looking at the developments of a computerised registration system taking

Device for protecting deformations of reactor cores

International Nuclear Information System (INIS)

Kato, Yasuyoshi; Urushihara, Hiroshi.

1975-01-01

Object: To provide a fluid pressure cylinder, which is operated according to change in temperature of coolant for a reactor to restrain or release a core, to simply and effectively protect deformation of the core. Structure: A closed fluid pressure cylinder interiorly filled with suitable fluid is disposed in peripherally equally spaced relation in an annular space between a core barrel of a reactor and a reactor vessel. A piston is mounted in fluid-tight fashion in a plurality of piston openings made in the cylinder, the piston being slidably moved according to expansion and contraction of the fluid filled in the cylinder. The piston has a movable frame mounted at the foremost end thereof, the movable frame being moved integral with the piston, and the surface opposite the mount thereof biasing the outermost peripheral surface of the core. (Kamimura, M.)

Coupling hydrodynamic modeling and empirical measures of bed mobility to assess the risk of redd scour on a large regulated river

Science.gov (United States)

Christine L. May; Bonnie S. Pryor; Thomas E. Lisle; Margaret M. Lang

2009-01-01

n order to assess the risk of scour and fill of spawning redds during floods, an understanding of the relations among river discharge, bed mobility, and scour and fill depths in areas of the streambed heavily utilized by spawning salmon is needed. Our approach coupled numerical flow modeling and empirical data from the Trinity River, California, to quantify spatially...

High-rate oil removing scouring agent. Koyubun jokyoyo seirenzai ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Ishihara, K.; Sato, Y. (Dai-Ichi Kogyo Seiyaku Co. Ltd., Kyoto (Japan))

1991-11-01

Fiber forming, scutching and knitting processes in recent years are performed three to five times faster than in the conventional processes. Associated therewith, oil solutions are taken importantly for their stability and workability, such as smoothing properties, heat resistance and abrasion resistance. On the other hand, difficulty is increasing in removing the oils after scutching and knitting. This paper explains basic rinsing activities required in oil removal, and describes various test characteristics and compatibility of various high-rate oil removing scouring agents. An oil-in-water rinsing mechanism relies upon comprehensive actions of a surfactant in wetting, permeation, emulsified dispersion and solubilization. The most importantly taken among them is the emulsifying action, which largely depends upon its chemical structure. Therefore, for a high-rate oil removing scouring agent, creation of activators is required that make the above basic characteristics and activities compatible for various applications. For example, the above product covers a great variety of kinds for diverse applications, based on non-ionic and anion-based activators. 6 figs., 20 tabs.

Numerical and experimental investigation of flow and scour around a half-buried sphere

DEFF Research Database (Denmark)

Dixen, Martin; Sumer, B. Mutlu; Fredsøe, Jørgen

2013-01-01

The paper describes the results of a numerical and experimental investigation of flow and scour around a half-buried sphere exposed to a steady current. Hot-film bed shear stress and Laser Doppler Anemometer measurements were made with a half sphere mounted on the smooth bed in an open channel......-buried sphere in currents. The morphologic model includes a sediment-transport description, and a description of surface-layer sand slides for bed slopes exceeding the angle of repose. The sediment transport description includes, for the first time, the effect of externally-generated turbulence (induced...... by the horseshoe-vortex flow and the lee-wake flow processes) on sediment transport. The results show that the scour depth increases and time scale decreases when the effect of externally-generated turbulence is incorporated in the calculations. Empirical expressions representing the numerically obtained data...

Seismic performance of an existing bridge with scoured caisson foundation

Science.gov (United States)

Chang, Kuo-Chun; Sung, Yu-Chi; Liu, Kuang-Yen; Wang, Ping-Hsiung; Lee, Zheng-Kuan; Lee, Lu-Sheng; Witarto

2014-08-01

This paper presents in-situ seismic performance tests of a bridge before its demolition due to accumulated scouring problem. The tests were conducted on three single columns and one caisson-type foundation. The three single columns were 1.8 m in diameter, reinforced by 30-D32 longitudinal reinforcements and laterally hooped by D16 reinforcements with spacing of 20 cm. The column height is 9.54 m, 10.59 m and 10.37 m for Column P2, P3, and P4, respectively. Column P2 had no exposed foundation and was subjected to pseudo-dynamic tests with peak ground acceleration of 0.32 g first, followed by one cyclic loading test. Column P3 was the benchmark specimen with exposed length of 1.2 m on its foundation. The exposed length for Column P4 was excavated to 4 m, approximately 1/3 of the foundation length, to study the effect of the scouring problem to the column performance. Both Column P3 and Column P4 were subjected to cyclic loading tests. Based on the test results, due to the large dimension of the caisson foundation and the well graded gravel soil type that provided large lateral resistance, the seismic performance among the three columns had only minor differences. Lateral push tests were also conducted on the caisson foundation at Column P5. The caisson was 12 m long and had circular cross-sections whose diameters were 5 m in the upper portion and 4 m in the lower portion. An analytical model to simulate the test results was developed in the OpenSees platform. The analytical model comprised nonlinear flexural elements as well as nonlinear soil springs. The analytical results closely followed the experimental test results. A parametric study to predict the behavior of the bridge column with different ground motions and different levels of scouring on the foundation are also discussed.

Simulation of beta radiator handling procedures in nuclear medicine by means of a movable hand phantom.

Science.gov (United States)

Blunck, Ch; Becker, F; Urban, M

2011-03-01

In nuclear medicine therapies, people working with beta radiators such as (90)Y may be exposed to non-negligible partial body doses. For radiation protection, it is important to know the characteristics of the radiation field and possible dose exposures at relevant positions in the working area. Besides extensive measurements, simulations can provide these data. For this purpose, a movable hand phantom for Monte Carlo simulations was developed. Specific beta radiator handling scenarios can be modelled interactively with forward kinematics or automatically with an inverse kinematics procedure. As a first investigation, the dose distribution on a medical doctor's hand injecting a (90)Y solution was measured and simulated with the phantom. Modelling was done with the interactive method based on five consecutive frames from a video recorded during the injection. Owing to the use of only one camera, not each detail of the radiation scenario is visible in the video. In spite of systematic uncertainties, the measured and simulated dose values are in good agreement.

Properties of bio-oil generated by a pyrolysis of forest cedar residuals with the movable Auger-type reactor

Energy Technology Data Exchange (ETDEWEB)

Nishimura, Shun; Ebitani, Kohki, E-mail: ebitani@jaist.ac.jp [School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Miyazato, Akio [Nanotechnology Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan)

2016-02-01

Our research project has developed the new movable reactor for bio-oil production in 2013 on the basis of Auger-type system. This package would be a great impact due to the concept of local production for local consumption in the hilly and mountainous area in not only Japan but also in the world. Herein, we would like to report the properties of the bio-oil generated by the developing Auger-type movable reactor. The synthesized bio-oil possessed C: 46.2 wt%, H: 6.5 wt%, N: wt%, S: <0.1 wt%, O: 46.8 wt% and H{sub 2}O: 18.4 wt%, and served a good calorific value of 18.1 MJ/kg. The spectroscopic and mass analyses such as FT-IR, GC-MS, {sup 13}C-NMR and FT-ICR MS supported that the bio-oil was composed by the fine mixtures of methoxy phenols and variety of alcohol or carboxylic acid functional groups. Thus, it is suggested that the bio-oil generated by the new movable Auger-type reactor has a significant potential as well as the existing bio-oil reported previously.

Properties of bio-oil generated by a pyrolysis of forest cedar residuals with the movable Auger-type reactor

International Nuclear Information System (INIS)

Nishimura, Shun; Ebitani, Kohki; Miyazato, Akio

2016-01-01

Our research project has developed the new movable reactor for bio-oil production in 2013 on the basis of Auger-type system. This package would be a great impact due to the concept of local production for local consumption in the hilly and mountainous area in not only Japan but also in the world. Herein, we would like to report the properties of the bio-oil generated by the developing Auger-type movable reactor. The synthesized bio-oil possessed C: 46.2 wt%, H: 6.5 wt%, N: wt%, S: <0.1 wt%, O: 46.8 wt% and H 2 O: 18.4 wt%, and served a good calorific value of 18.1 MJ/kg. The spectroscopic and mass analyses such as FT-IR, GC-MS, 13 C-NMR and FT-ICR MS supported that the bio-oil was composed by the fine mixtures of methoxy phenols and variety of alcohol or carboxylic acid functional groups. Thus, it is suggested that the bio-oil generated by the new movable Auger-type reactor has a significant potential as well as the existing bio-oil reported previously

Experimental Study of the Effect of W-weir on Reduction of Scour Depth at 90 Degree Sharp Bend

Directory of Open Access Journals (Sweden)

Vida Atashi

2017-02-01

Full Text Available Introduction: Flow patterns within the river bend is three dimensional. Occurrence of secondary flow due to centrifugal force and formation of helicoidally vortex in river bend usually causes the outer bank of river erodes whilst the sediment are deposited in inner bend which appears in the form of point bars. To reduce the river bank scour, many techniques have been developed which may be classified as covering technique and modified flow patterns methods. The W-weir is among such structures. In the present paper, by measuring three components of flow velocity with and without presence of W-weir, variation of flow patterns and shear stress distribution in a 90-degree sharp bend have been investigated. The main purpose of this study is to see the installation of different locations of W-weir in the bend on reduction of outer bank scour. In the present paper, by measuring three components of flow velocity with and without presence of W-weir, variation of flow patterns and shear stress distribution in a 90-degree sharp bend have been investigated. The analyses of data showed more uniform flow upstream of the weir and also revealed that the effect of transverse and centrifugal forces are modified in such a way that the secondary flow is diminished. The results showed that for 30, 60 and 90-degree bends maximum erosion depth in the vicinity of the outer bank with Froude number of 0.206 in comparison with 0.137 has increased up to 84, 90 and 118 % respectively. In both Froude numbers, installation of W-Weir in 30 degree has the most reduction in bed in comparison with 60 and 90 degree. Materials and Methods: To reach the goal of this study a physical model of 90 degree sharp bend was constructed in the hydraulic lab of Shahid Chamran university of Ahvaz. The ratio of R(radius/b(flume width was less than 2 which shows a sharp bend. The W-weir was built with 1mm galvanized steel. Flume bed was covered with sediment of D50=1.5mm. The W-weir was

Electrodeposition of nickel onto steel, using a thermostatic cell and movable anode by a variable current

International Nuclear Information System (INIS)

Vega G, J.D.

1994-01-01

In this work, metallic coatings of nickel was made over carbon steel using two different electrolytic solutions: The Watts's bath and the nickel sulfamate bath, using a pulse variable current. The method use was the traditional method, its means a thermostatic cell and one movable anode, which is a few know technique nowadays, it allow realize depositions away from any laboratory or special workshop, it has the advantage to be a portable dispositive. At last of all the electro depositions the coatings quality was valuable by them physical properties like: adhesion, hardness, wrinkled and thickness. The best results was obtain by the Nickel sulfamate bath and movable anode, less in the thickness, which has higher on the thermostatic cell. The variable current was obtain by a Pulse Generator and a Cathodic galvanometer. (Author)

Design of movable fixed area γ dose rate monitor

International Nuclear Information System (INIS)

Li Dongyu; Cheng Wen; Li Jikai; Huang Hong; Shen Qiming; Zhang Qiang; Liu Zhengshan

2005-10-01

Movable fixed area γ dose rate monitor has not only the characteristics of fixed area γ dose rate monitor, but that of portable meter as well. Its main function is to monitor the areas where dose rate would change without orderliness to prevent unplanned radiation exposure accidents from happening. The design way of the monitor, the main indicators description, the working principle and the comprising of software and hardware are briefly introduced. The monitor has the characteristics of simple installation, easy maintenance, little power consumption, wide range, notability of visual and audible alarm and so on. Its design and technique have novelty and advancement. (authors)

Assessment of bridge abutment scour and sediment transport under various flow conditions

Science.gov (United States)

Gilja, Gordon; Valyrakis, Manousos; Michalis, Panagiotis; Bekić, Damir; Kuspilić, Neven; McKeogh, Eamon

2017-04-01

Safety of bridges over watercourses can be compromised by flow characteristics and bridge hydraulics. Scour process around bridge foundations can develop rapidly during low-recurrence interval floods when structural elements are exposed to increased flows. Variations in riverbed geometry, as a result of sediment removal and deposition processes, can increase flood-induced hazard at bridge sites with catastrophic failures and destructive consequences for civil infrastructure. The quantification of flood induced hazard on bridge safety generally involves coupled hydrodynamic and sediment transport models (i.e. 2D numerical or physical models) for a range of hydrological events covering both high and low flows. Modelled boundary conditions are usually estimated for their probability of occurrence using frequency analysis of long-term recordings at gauging stations. At smaller rivers gauging station records are scarce, especially in upper courses of rivers where weirs, drops and rapids are common elements of river bathymetry. As a result, boundary conditions that accurately represent flow patterns on modelled river reach cannot be often reliably acquired. Sediment transport process is also more complicated to describe due to its complexity and dependence to local flow field making scour hazard assessment a particularly challenging issue. This study investigates the influence of flow characteristics to the development of scour and sedimentation processes around bridge abutments of a single span masonry arch bridge in south Ireland. The impact of downstream weirs on bridge hydraulics through variation of downstream model domain type is also considered in this study. The numerical model is established based on detailed bathymetry data surveyed along a rectangular grid of 50cm spacing. Acquired data also consist of riverbed morphology and water level variations which are monitored continuously on bridge site. The obtained data are then used to compare and calibrate

Prevalence and Comparative Studies of Some Major Serotype of E.Coli from Cattle and Buffalo Calf Scour

Directory of Open Access Journals (Sweden)

Vagh A.A. and Jani R.G.

Full Text Available A study was carried out to find the different serotype of E.coli isolates from the young cattle and buffalo calves affected with calf scours. Different strains of E. coli were isolated from 30 cases of calf scour from both cattle and buffalo calves each. All the isolates of E. coli were typed for ‘O’ antigen. The relationship of serotypes of E. coli to each case showed that two of the twenty six serotypes were common and appeared most virulent in both the species. [Veterinary World 2010; 3(10.000: 458-459

Smoothed Particle Hydrodynamics Simulations of Dam-Break Flows Around Movable Structures

OpenAIRE

Jian, Wei; Liang, Dongfang; Shao, Songdong; Chen, Ridong; Yang, Kejun

2015-01-01

In this paper, 3D weakly compressible and incompressible Smoothed Particle Hydrodynamics (WCSPH & ISPH) models are used to study dam-break flows impacting on either a fixed or a movable structure. First, the two models’ performances are compared in terms of CPU time efficiency and numerical accuracy, as well as the water surface shapes and pressure fields. Then, they are applied to investigate dam-break flow interactions with structures placed in the path of the flood. The study found that th...

Tsunami Induced Scour Around Monopile Foundations

DEFF Research Database (Denmark)

Eltard-Larsen, Bjarke; Fuhrman, David R.; Baykal, Cüneyt

2017-01-01

A fully-coupled (hydrodynamic and morphologic) numerical model is presented, and utilized for the simulation of tsunami-induced scour around a monopile structure, representative of those commonly utilized as offshore wind turbine foundations at moderate depths i.e. for depths less than 30 m...... a steady current, where a generally excellent match with experimentally-based results is found. A methodology for maintaining and assessing hydrodynamic and morphologic similarity between field and (laboratory) model-scale tsunami events is then presented, combining diameter-based Froude number similarity...... with that based on the dimensionless wave boundary layer thickness-to-monopile diameter ratio. This methodology is utilized directly in the selection of governing tsunami wave parameters (i.e. velocity magnitude and period) used for subsequent simulation within the numerical model, with the tsunami-induced flow...

Modelling Scour in Front of Dune Revetments in a Surf-beat Model

NARCIS (Netherlands)

Van Geer, P.F.C.; Van Thiel de Vries, J.S.M.; Boers, M.; Den Bieman, J.P.; McCall, R.T.

2014-01-01

This paper presents adaptations to the XBeach model aimed at including the relevant processes for the generation of scour holes at the toe of a revetment. Dutch assessment rules for the safety of sea defenses need to be adjusted to cope with a combination of sandy dunes and hard elements. To that

Topological design of compliant smart structures with embedded movable actuators

International Nuclear Information System (INIS)

Wang, Yiqiang; Zhang, Xiaopeng; Kang, Zhan; Luo, Zhen

2014-01-01

In the optimal configuration design of piezoelectric smart structures, it is favorable to use actuation elements with certain predefined geometries from the viewpoint of manufacturability of fragile piezoelectric ceramics in practical applications. However, preserving the exact shape of these embedded actuators and tracking their dynamic motions presents a more challenging research task than merely allowing them to take arbitrary shapes. This paper proposes an integrated topology optimization method for the systematic design of compliant smart structures with embedded movable PZT (lead zirconate titanate) actuators. Compared with most existing studies, which either optimize positions/sizes of the actuators in a given host structure or design the host structure with pre-determined actuator locations, the proposed method simultaneously optimizes the positions of the movable PZT actuators and the topology of the host structure, typically a compliant mechanism for amplifying the small strain stroke. A combined topological description model is employed in the optimization, where the level set model is used to track the movements of the PZT actuators and the independent point-wise density interpolation (iPDI) approach is utilized to search for the optimal topology of the host structure. Furthermore, we define an integral-type constraint function to prevent overlaps between the PZT actuators and between the actuators and the external boundaries of the design domain. Such a constraint provides a unified and explicit mathematical statement of the non-overlap condition for any number of arbitrarily shaped embedded actuators. Several numerical examples are used to demonstrate the effectiveness of the proposed optimization method. (paper)

Bridge scour and stream instability countermeasures : experience, selection, and design guidance : third edition. Volume 1

Science.gov (United States)

2009-09-01

This document identifies and provides design guidelines for bridge scour and stream instability countermeasures that have been implemented by various State departments of transportation (DOTs) in the United States. Countermeasure experience, selectio...

Bridge scour and stream instability countermeasures : experience, selection, and design guidance : third edition. Volume 2

Science.gov (United States)

2009-09-01

This document identifies and provides design guidelines for bridge scour and stream instability countermeasures that have been implemented by various State departments of transportation (DOTs) in the United States. Countermeasure experience, selectio...

Multilevel power distribution synthesis for a movable flux mapping system

International Nuclear Information System (INIS)

Bollacasa, D.; Terney, W.B.; Vincent, G.F.; Dziadosz, D.; Schleicher, T.

1992-01-01

A Computer Software package has been developed to support the synthesis of the 3-dimensional power distribution from detector signals from a movable flux mapping system. The power distribution synthesis is based on methodology developed for fixed incore detectors. The full core solution effectively couples all assemblies in the core whether they are instrumented or not. The solution is not subject to approximations for the treatment of assemblies where a measurement cannot be made and provides an accurate representation of axial variations which may be induced by axial blankets, burnable absorber cut back regions and axially zoned flux suppression rods

Prediction of scour caused by 2D horizontal jets using soft computing techniques

Directory of Open Access Journals (Sweden)

Masoud Karbasi

2017-12-01

Full Text Available This paper presents application of five soft-computing techniques, artificial neural networks, support vector regression, gene expression programming, grouping method of data handling (GMDH neural network and adaptive-network-based fuzzy inference system, to predict maximum scour hole depth downstream of a sluice gate. The input parameters affecting the scour depth are the sediment size and its gradation, apron length, sluice gate opening, jet Froude number and the tail water depth. Six non-dimensional parameters were achieved to define a functional relationship between the input and output variables. Published data were used from the experimental researches. The results of soft-computing techniques were compared with empirical and regression based equations. The results obtained from the soft-computing techniques are superior to those of empirical and regression based equations. Comparison of soft-computing techniques showed that accuracy of the ANN model is higher than other models (RMSE = 0.869. A new GEP based equation was proposed.

Towards a whole-network risk assessment for railway bridge failures caused by scour during flood events

Directory of Open Access Journals (Sweden)

Lamb Rob

2016-01-01

Full Text Available Localised erosion (scour during flood flow conditions can lead to costly damage or catastrophic failure of bridges, and in some cases loss of life or significant disruption to transport networks. Here, we take a broad scale view to assess risk associated with bridge scour during flood events over an entire infrastructure network, illustrating the analysis with data from the British railways. There have been 54 recorded events since 1846 in which scour led to the failure of railway bridges in Britain. These events tended to occur during periods of extremely high river flow, although there is uncertainty about the precise conditions under which failures occur, which motivates a probabilistic analysis of the failure events. We show how data from the historical bridge failures, combined with hydrological analysis, have been used to construct fragility curves that quantify the conditional probability of bridge failure as a function of river flow, accompanied by estimates of the associated uncertainty. The new fragility analysis is tested using flood events simulated from a national, spatial joint probability model for extremes in river flows. The combined models appear robust in comparison with historical observations of the expected number of bridge failures in a flood event, and provide an empirical basis for further broad-scale network risk analysis.

Sinking of armour layer around a cylinder exposed to a current

DEFF Research Database (Denmark)

Nielsen, Anders Wedel; Sumer, B. Mutlu; Fredsøe, Jørgen

2011-01-01

The flow processes in a scour protection around a monopile in steady current are described in relation to transport of sediment in the scour protection based on physical model tests. The scour protection consisted of uniformly distributed coarse stones without filter layer. Transport of sediment ...

Application of Bridge Pier Scour Equations for Large Woody Vegetation

Science.gov (United States)

2016-07-01

velocities and, thus, reduces boundary shear stress , the primary driver of sediment erosion. Even if this vegetation should become uprooted, the smaller...ER D C TR -1 6- 10 Application of Bridge Pier Scour Equations for Large Woody Vegetation En gi ne er R es ea rc h an d D ev el op m...K. Corcoran, and Kevin S. Holden July 2016 Approved for public release ; distribution is unlimited. The U.S. Army Engineer Research and

Design of TFTR movable limiter blades for ohmic and neutral-beam-heated plasmas

International Nuclear Information System (INIS)

Doll, D.W.; Ulrickson, M.A.; Cecchi, J.L.; Citrolo, J.C.; Weissenburger, D.; Bialek, J.

1981-10-01

A new set of movable limiter blades has been designed for TFTR that will meet both the requirements of the 4 MW ohmic heated and the 33 MW neutral beam heated plasmas. This is accomplished with three limiter blades each having and elliptical shape along the toroidal direction. Heat flux levels are acceptable for both ohmic heated and pre-strong compression plasmas. The construction consists of graphite tiles attached to cooled backing plates. The tiles have an average thickness of approx. 4.7 cm and are drawn against the backing plate with spring loaded fasteners that are keyed into the graphite. The cooled backing plate provides the structure for resisting disruption and fault induced loads. A set of rollers attached to the top and bottom blades allow them to be expanded and closed in order to vary the plasma surface for scaling experiments. Water cooling lines penetrate only the mid-plane port cover/support plate in such a way as to avoid bolted water connections inside the vacuum boundary and at the same time allow blade movement. Both the upper and lower blades are attached to the mid-plane limiter blade through pivots. Pivot connections are protected against arcing with an alumina coating and a shunt bar strap. Remote handling is considered throughout the design

An energy-harvesting power supply for underwater bridge scour monitoring sensors

Science.gov (United States)

Wang, Yuli; Li, Yingjie; He, Longzhuang; Shamsi, Pourya; Zheng, Yahong R.

2018-03-01

The natural force of scouring has become one of the most critical risk endangering the endurance of bridges, thus leading to the necessity of deploying underwater monitoring sensors to actively detect potential scour holes under bridges. Due to the difficulty in re-charging batteries for underwater sensors, super capacitors with energy harvesting (EH) means are exploited to prolong the sustainability of underwater sensors. In this paper, an energy harvesting power supply based on a helical turbine is proposed to power underwater monitoring sensors. A small helical turbine is designed to convert water flow energy to electrical energy with favorable environmental robustness. A 3-inch diameter, 2.5-inch length and 3-bladed helical turbine was designed with two types of waterproof coupling with the sensor housing. Both designs were prototyped and tested under different flow conditions and we get valid voltage around 0.91 V which is enough to power monitoring sensor. The alternating current (AC) electrical energy generated by the helical turbine is then rectified and boosted to drive a DC charger for efficiently charging one super capacitor. The charging circuit was designed, prototyped and tested thoroughly with the helical turbine harvester. The results were promising, that the overall power supply can power an underwater sensor node with wireless transceivers for long-term operations

A sustainable and green process for scouring of cotton fabrics using xylano-pectinolytic synergism: switching from noxious chemicals to eco-friendly catalysts.

Science.gov (United States)

Singh, Avtar; Kaur, Amanjot; Patra, Arun Kumar; Mahajan, Ritu

2018-04-01

The objective of this research was to develop an appropriate, eco-friendly, cost-effective bioscouring methodology for removing natural impurities from cotton fabric. Maximum bioscouring was achieved using 5.0 IU xylanase and 4.0 IU pectinase with material to liquid ratio of 1:15 in a 50 mM buffer (glycine-NaOH buffer, 1.0 mM EDTA and 1% Tween-80, pH 8.5) with a treatment time of 60 min at 50 °C and an agitation speed of 60 rpm. The bioscoured cotton fabrics showed a gain of 1.17% in whiteness, 3.23% in brightness and a reduction of 4.18% in yellowness in comparison to fabric scoured with an alkaline scouring method. Further, after bleaching, the whiteness, brightness and tensile strength of the bioscoured fabrics were increased by 2.18, 2.33 and 11.74% along with a decrease of 4.61% in yellowness of bioscoured plus bleached fabrics in comparison to chemically scoured plus bleached fabrics. From the results, it is clear that bioscouring is more efficient, energy saving and an eco-friendly process and has the potential to replace the environment-damaging scouring process with the xylano-pectinolytic bioscouring process.

Effects of the partially movable control fin with end plate of underwater vehicle

Directory of Open Access Journals (Sweden)

Chul-Min Jung

2017-01-01

Full Text Available Underwater torpedo has control fin with very low aspect ratio due to launching from limited size of cylindrical torpedo tube. If the aspect ratio of control fin of underwater vehicle is very low three-dimensional flow around control fin largely reduces control forces. In this study, the end plate was applied to reduce the three-dimensional flow effects of partially movable control fin of underwater vehicle. Through numerical simulations the flow field around control fin was examined with and without end plate for different flap angles. The pressure, vorticity, lift and torque on the control fin were analyzed and compared to experiments. The comparison have shown a reasonable agreement between numerical and experimental results and the effect of end plate on a low aspect ratio control fin. When the end plate was attached to the movable control fin, the lift increased and the actuator shaft torque did not significantly change. As this means less consumption of the actuator shaft torque compared to the control fin that has the same control force, the inner actuator capacity can be reduced and energy consumption can be saved. Considering this, it is expected to be effectively applied to the control fin design of underwater vehicles such as torpedoes.

[FEATURES OF THE CONTENT OF MOVABLE FORMS OF HEAVY METALS AND SELENIUM IN SOILS OF THE YAROSLAVL REGION].

Science.gov (United States)

Bakaeva, E A; Eremeyshvili, A V

2016-01-01

With the use of the method of inversion voltammetry there was analyzed the content of movableforms of trace elements: (selenium, zinc, copper lead, cadmium) in soils in the Yaroslavl district of the Yaroslavl region, and also content of zinc, copper lead, cadmium in soils and snow cover in the city of Yaroslavl. According to values of concentrations of movable compounds in soils determined trace elements can be ranked into the following row: zinc > lead > copper > selenium > cadmium. There was revealed insufficient if compared with literature data concentrations, content of movable compounds of selenium, copper and zinc in examined explored soils. The maximal concentrations of lead are revealed in the close proximity to both the city of Yaroslavl and large highways of the city. It indicates to the anthropogenic pollution of soils by this element.

The impacts of climate change on scour-vulnerable bridges : an assessment based on HYRISK.

Science.gov (United States)

2011-10-01

More than 20% of the bridges in the U.S. were built more than 50 years ago, at a time in which : intense precipitation events were much less common. However, very little work has been done : on the use of scour risk-assessment models to assess how cl...

Preoperative diagnosis and radiographic findings of a freely movable mucocele of the vermiform appendix

Energy Technology Data Exchange (ETDEWEB)

Shukunami, K.-I.; Kaneshima, M.; Kotsuji, F. [Fukui Medical Univ., Dept. of Obstetrics and Gynecology, Matsuoka-Cho, Yoshida-Gun, Fukui (Japan)

2000-10-01

Mucocele of the vermiform appendix is rarely diagnosed before surgery, although radiologic and ultrasonographic (US) findings have been reported. To our knowledge, there have been no previous reports of 2 different radiologic images of the cyst in the same patient during the preoperative period. We present 2 different shapes and locations of a freely movable mucocele of the appendix as it appeared before surgery. (author)

Radiation protecting clothing materials

International Nuclear Information System (INIS)

Mio, Kotaro; Ijiri, Yasuo.

1986-01-01

Purpose: To provide radiation protecting clothing materials excellent in mechanical strength, corrosion resistance, flexibility and flexing strength. Constitution: The radiation protecting clothing materials according to this invention has pure lead sheets comprising a thin pure lead foil of 50 to 150 μm and radiation resistant organic materials, for example, polyethylene with high neutron shielding effect disposed to one or both surfaces thereof. The material are excellent in the repeating bending fatigue and mechanical strength, corrosion resistance and flexibility and, accordingly, radiation protecting clothings prepared by using them along or laminating them also possess these excellent characteristics. Further, they are excellent in the handlability, particularly, durability to the repeated holding and extension, as well as are preferable in the physical movability and feeling upon putting. The clothing materials may be cut into an appropriate size, or stitched into clothings made by radiation-resistant materials. In this case, pure lead sheets are used in lamination. (Horiuchi, T.)

Movable air solar collector and its efficiency

International Nuclear Information System (INIS)

Lauva, A.; Aboltinš, A.; Palabinskis, J.; Karpova Sadigova, N.

2008-01-01

Implementing the guidelines of the Latvian National Programme for Energy in the field of alternative energy, intensive research shall be carried on regarding the use of solar energy, as it can be successfully used not only for the purposes of water heating and production of electrical energy, but also for air warming. The amount of heat necessary for the drying of rough forage and grain drying by active aeration in June, July and August can be obtained using solar radiation. The Latvian Guidelines for the Energy Development 2006-2016 state that the solar radiance in Latvia is of quite low intensity. The total amount of solar energy is 1109 kWh m -2 per year. The period of usage of the solar thermal energy is beginning from the last decade of April, when the intensity of radiation is 120 kWh m -2 , until the first decade of September. Within this period (approximately 1800 hours), it is possible to use the solar thermal energy by placing solar collectors. The usage of solar collectors for in drying of agricultural production is topical from the viewpoint of decreasing the consumption of energy used for the drying, as electrical energy and fossil energy resources become more expensive and tend to run out. In the processes that concern drying of agricultural production, efficiently enough solar radiation energy can be used. Due to this reason researching continues and expands in the field of usage of solar energy for the processes of drying and heating. The efficiency factor of the existing solar collectors is not high, but they are of simple design and cheep for production and exploitation. By improving the design of the solar collectors and choosing modern materials that absorb the solar radiation energy, it is possible the decrease the efficiency factor of solar collectors and decrease the production costs. In the scientific laboratory of grain drying and storage of Latvia University of Agriculture, a pilot device movable folding solar collector pilot device

Nitrifying bio-cord reactor: performance optimization and effects of substratum and air scouring.

Science.gov (United States)

Tian, Xin; Ahmed, Warsama; Delatolla, Robert

2017-11-20

Ammonia removal kinetics and solids' production performance of the bio-cord technology are studied in this research. Three nitrifying reactors housing different bio-cord substratum were operated at five different ammonia loading rates. All of the bio-cord substrata demonstrated stable and high ammonia-nitrogen removal efficiencies of 96.8 ± 0.9%, 97.0 ± 0.6% and 92.0 ± 0.4% at loading rates of 0.8, 1.6 and 1.8 g [Formula: see text]-N/m 2  d, respectively. At these same loading rates, the bio-cord reactors housing the three substrata also showed low solids' production rates of 0.19 ± 0.03, 0.23 ± 0.02, 0.25 ± 0.03 g total suspended solids/d. A reduction of system stability, identified via fluctuating ammonia removal rates, was however observed for all substrata at loading rates of 2.1 and 2.4 g [Formula: see text]-N/m 2  d. Further, the solids' production rates at these higher loading conditions were also observed to fluctuate for all substrata, likely indicating intermediate sloughing events. The effects of enhancing the air scouring of the bio-cord on the ammonia removal rate was shown to be dependent upon the substratum, while enhanced air scouring of the bio-cord was shown to stabilize the production of solids for all substrata. This study represents the first performance and optimization study of the bio-cord technology for low-carbon nitrification and shows that air scouring of the substratum reduces sloughing events at elevated loading and that the bio-cord technology achieves stable kinetics above conventional rates of 1 g [Formula: see text]-N/m 2  d to values of 1.8 g [Formula: see text]-N/m 2  d.

Development of a movable table for a bending magnet with removable guides

International Nuclear Information System (INIS)

Shibuya, T.; Ito, I.; Kudoh, H.

2004-01-01

We develop the movable table for a bending magnet with removable guides. This table has two parallel rails in order to move the bending magnet smoothly and set it precisely. Especially this table has two removable expanded rail guides. Removing this expanded rail guides allow us to make more enough spaces, for example, to install another insertion devices. We measure the reliability of setting this table by moving this table along the rails. And we found this reliability is less than ±3 μm. We also measure the long-term stability of this table setting. (author)

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

Science.gov (United States)

Conaway, Jeffrey S.; Brabets, Timothy P.

2011-01-01

The Copper River Highway traverses a dynamic and complex network of braided and readily erodible channels that constitute the Copper River Delta, Alaska, by way of 11 bridges. Over the past decade, several of these bridges and the highway have sustained serious damage from both high and low flows and channel instability. This investigation studying the impact of channel migration on the highway incorporates data from scour monitoring, lidar surveys, bathymetry, hydrology, and time-lapse photography.

Extending the magnetoelectric efficiency of an MFC/brass/NdFeB energy harvester by coupling a pair of movable magnets

Science.gov (United States)

Leung, Chung Ming; Wang, Ya

2017-10-01

In this letter, an MFC/brass/NdFeB tip magnet three-phase cantilever beam was coupled with a pair of movable magnets to harness energy from alternating magnetic fields. By coupling with a pair of moveable magnets, both bandwidth and magnetoelectric (ME) voltage coefficient (α\\text{V}) were largely increased by 25% and 87.5%, respectively, in comparison with the same harvester coupled with stationary magnets. Such improvements were attributed to magnetic energy introduced by the moving magnets. Experiments also revealed the boundary positions of external magnets (movable and stationary) where the repulsive magnetic forces jumped to the attractive ones, and the stiffness hardening switched to the softening process. These results provided a wide-band nonlinear approach to efficiently harvest/detect the low-frequency alternating magnetic field energies.

Prediction of scour depth in gravel bed rivers using radio frequency IDs : application to the Skagit River.

Science.gov (United States)

2013-10-01

The overarching goal of the proposed research was to develop, test and verify a robust system based on the Low Frequency (134.2 : kHz), passive Radio Frequency Identification (RFID) technology to be ultimately used for determining the maximum scour d...

Experimental study of 2D scour and its protection at a rubble-mound breakwater

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Fredsøe, Jørgen

2000-01-01

investigated for the following cases: (1) the protection apron with one layer of stones and (2) that with several layers of stones. The mechanism of slumping down of stones of the protection apron was also considered. The results of the toe protection study are given in the form of diagrams....

Character, distribution, and ecological significance of storm wave-induced scour in Rhode Island Sound, USA

Science.gov (United States)

McMullen, Katherine Y.; Poppe, Lawrence J.; Parker, Castle E.

2015-01-01

Multibeam bathymetry, collected during NOAA hydrographic surveys in 2008 and 2009, is coupled with USGS data from sampling and photographic stations to map the seabed morphology and composition of Rhode Island Sound along the US Atlantic coast, and to provide information on sediment transport and benthic habitats. Patchworks of scour depressions cover large areas on seaward-facing slopes and bathymetric highs in the sound. These depressions average 0.5-0.8 m deep and occur in water depths reaching as much as 42 m. They have relatively steep well-defined sides and coarser-grained floors, and vary strongly in shape, size, and configuration. Some individual scour depressions have apparently expanded to combine with adjacent depressions, forming larger eroded areas that commonly contain outliers of the original seafloor sediments. Where cobbles and scattered boulders are present on the depression floors, the muddy Holocene sands have been completely removed and the winnowed relict Pleistocene deposits exposed. Low tidal-current velocities and the lack of obstacle marks suggest that bidirectional tidal currents alone are not capable of forming these features. These depressions are formed and maintained under high-energy shelf conditions owing to repetitive cyclic loading imposed by high-amplitude, long-period, storm-driven waves that reduce the effective shear strength of the sediment, cause resuspension, and expose the suspended sediments to erosion by wind-driven and tidal currents. Because epifauna dominate on gravel floors of the depressions and infauna are prevalent in the finer-grained Holocene deposits, it is concluded that the resultant close juxtaposition of silty sand-, sand-, and gravel-dependent communities promotes regional faunal complexity. These findings expand on earlier interpretations, documenting how storm wave-induced scour produces sorted bedforms that control much of the benthic geologic and biologic diversity in Rhode Island Sound.

Design, simulation and fabrication of a novel contact-enhanced MEMS inertial switch with a movable contact point

International Nuclear Information System (INIS)

Cai Haogang; Ding Guifu; Yang Zhuoqing; Su Zhijuan; Zhou Jiansheng; Wang Hong

2008-01-01

A novel inertial switch based on a micro-electro-mechanical system (MEMS) was designed, which consists of three main parts: a proof mass as the movable electrode, a cross beam as the stationary electrode and a movable contact point to prolong the contact time. A MATLAB/Simulink model, which had been verified by comparison with ANSYS transient simulation, was built to simulate the dynamic response, based on which the contact-enhancing mechanism was confirmed and the dependence of threshold acceleration on the proof mass thickness was studied. The simulated dynamic responses under various accelerations exhibit satisfactory device behaviors: the switch-on time is prolonged under transient acceleration; the switch-on state is more continuous than the conventional design under long lasting acceleration. The inertial micro-switch was fabricated by multilayer electroplating technology and then tested by a drop hammer experiment. The test results indicate that the contact effect was improved significantly and a steady switch-on time of over 50 µs was observed under half-sine wave acceleration with 1 ms duration, in agreement with the dynamic simulation

Nuclear Reactor RA Safety Report, Vol. 9, Radiation protection

International Nuclear Information System (INIS)

1986-11-01

Instrumentation for Radiation protection existing at the RA reactor is dating mostly from the period 1957-1959 when the reactor has been built. With some minor exception it was produced in USSR. Radiation protection system was constructed based on specific design project, somewhat modified original USSR project which has been indispensable because of some modification of the building design. During the past 27 years no renewal of the instrumentation was done, only maintenance was performed. Instrumentation consists of old electronic devices which caused difficulties and even prevented regular maintenance because of lack of spare parts. Instrumentation for radiation protection at the RA reactor is classified as follows: centralized dosimetry system; stationary dosimetry instrumentation, movable and personal dosimetry systems. Apart from the scheme of dosimetry instrumentation this volume includes description of radiation protection procedures; protection devices; radiation doses and dose limit data; program for environmental radioactivity control; medical control procedures [sr

The treatment and purification of wool and mohair scouring wastes- a survey

CSIR Research Space (South Africa)

Mozes, TE

1982-08-01

Full Text Available fraction of suspended dirt of inorganic nature (hereafter called 'sus- pended solids') in the scouring wastes includes predominantly sand and dust particles originally on the fibre. These clay particles, varying within a wide range of sizes, have been.... In practice, however, the grease was of poor quality and still contained a large amount of dirt. Potassium recovery failed completely because, as we now know, the centrifuges could not remove alI the grease from the emulsion and the subsequent calcining...

The Effect of Discharge Ratio and Confluence Angle on Local Scouring at 60 Degree Erodible Open Channel with SSIIM1 Model

Directory of Open Access Journals (Sweden)

R. Ghobadian

2016-10-01

Full Text Available Introduction: Flow and sediment transport has an important role in entrance deformation of open channel junctions. As water moved through a drainage network, it forced to converge at confluence. Due to increasing of water discharge and collision of converging flows, a complex three-dimensional and most highly turbulent location were occurred in the vicinity of the junction. Therefore a deep scour hole and point bar has developed in this area that caused the change in rivers morphology. Despite the large amount of research carried out on flow patterns in river confluences, only a few researches have focused on sediment transport. Materials and methods: In this research three dimensional model (SSIIM1 was used to study of flow pattern and sediment and erosion pattern at 60 degree Junction .the Navier-Stockes equation of turbulent flow in a general three-dimensional geometry are solved to obtain the water velocity: , (1 Where U is average velocity, ρ is density of water, is pressure, the Kronecker delta, which is 1 if i is equal to j and 0 otherwise and general space dimension. The last term is Reynolds stress, often modeled with the following equation: (2 Where and k are eddy viscosity and turbulent kinetic energy respectively. Van Rijn's relations were used to calculate sediment suspended and bed load transport. Dirichlet and zero gradients boundary conditions were used at inflow and outflow boundary respectively. fixed-lid approach was used to computed free surface by using zero gradient for all variables. The wall law for rough boundaries was also used as a boundary condition for bed and wall. In equilibrium situation, The sediment concentration for the cell closet to the bed was specified as the bed boundary condition. Specified value was used for sediment concentration of other boundary conditions at upstream boundary and zero gradients for the water surface, outlet, and the sides. the only simulation of local scouring and sedimentation at

Scour hole ('wielen') sediments as historical archive of floods, vegetation, and air and water quality in lowlands

NARCIS (Netherlands)

Cremer, Holger; van Hoof, Thomas; Bunnik, Frans; Donders, Timme

2010-01-01

The sediment record from a maximum 18 m deep scour hole lake (Haarsteegse Wiel) near the embanked Meuse River in the Netherlands was studied for past changes in flooding frequency, water quality, and landscape change using a combined geochemical, geobiological and historical approach. The results

Specification for movable manipulator system for use in radiochemical engineering cells

International Nuclear Information System (INIS)

Dixson, G.E.

1998-01-01

This specification was prepared to identify requirements for a movable manipulator for use in B-Ccl 1 and the REC Airlock at 324 Building. This manipulator could also be used in other hot cells at the 324 Building. This work involves retrieval, inspection, reduction and decontamination of material on the Airlock and Cell floors, in the pipe trench and on the walls. B and W Hanford Company (BWHC) recognizes that not all of the requirements are compatible and some may need to be changed, subject to agreement between the parties involved. BWHC also recognizes that in order to perform the tasks described two or more different machines with significantly different layout may be necessary. These requirements are the starting point for any proposal

Experimental study on the scram of electromagnetic movable coil control rod drive mechanism

International Nuclear Information System (INIS)

Sun Changlong; Bo Hanliang; Jiang Shengyao; Zhang Hongchao; Ma Cang; Wang Jinhua; Qin Benke

2006-01-01

Electromagnetic movable coil control rod drive mechanism is a new type drive mechanism. The drive mechanism is experimentally studied to gain the characteristic of scram time. Further more, the reason of the different scram phenomena is analyzed and the disciplinarian of scram is also summarized. On the base of series experiments it can be concluded that scram time of AC break is longer than that of DC break and the residual current of coil's can distinctly influence the scram time. The scram time of AC break is 300-700 ms longer than that of DC break. (authors)

Infrasound Assessment of Infrastructure Report 6: Scour Detection and Riverine Health Assessment Using Infrasound

Science.gov (United States)

2016-05-01

obtained from a soil map of the Ft. Leonard Wood area published by the U.S. Department of Agriculture and National Resources Conservation Service (Larsen...characteristics of two highway bridges with known scour problems in Taiwan . Their research began with finite element (FE) models of a simplified bridge...Washington, DC: United States Department of Agriculture - National Resources Conservation Service. Lee, W., T. T. Cheng, C.H. Chen, and J. Lai

The movable polarized target as a basic equipment for high energy spin physics experiments at the JINR-Dubna accelerator complex

Energy Technology Data Exchange (ETDEWEB)

Lehar, F.; Adiasevich, B.; Androsov, V.P.; Angelov, N.; Anischenko, N.; Antonenko, V.; Ball, J.; Baryshevsky, V.G.; Bazhanov, N.A.; Belyaev, A.A.; Benda, B.; Bodyagin, V.; Borisov, N.; Borzunov, Yu.; Bradamante, F.; Bunyatova, E.; Burinov, V.; Chernykh, E.; Combet, M.; Datskov, A.; Durand, G.; Dzyubak, A.P.; Fontaine, J.M.; Get`man, V.A.; Giorgi, M.; Golovanov, L.; Grebenyuk, V.; Grosnick, D.; Gurevich, G.; Hasegawa, T.; Hill, D.; Horikawa, N.; Igo, G.; Janout, Z.; Kalinnikov, V.A.; Karnaukhov, I.M.; Kasprzyk, T.; Khachaturov, B.A.; Kirillov, A.; Kisselev, Yu.; Kousmine, E.S.; Kovalenko, A.; Kovaljov, A.I.; Ladygin, V.P.; Lazarev, A.; Leconte, P.; Lesquen, A. de; Lukhanin, A.A.; Mango, S.; Martin, A.; Matafonov, V.N.; Matyushevsky, E.; Mironov, S.; Neganov, A.B.; Neganov, B.S.; Nomofilov, A.; Perelygin, V.; Plis, Yu.; Pilipenko, Yu.; Pisarev, I.L.; Piskunov, N.; Polunin, Yu.; Popkov, Yu.P.; Propov, A.A.; Prokofiev, A.N.; Rekalo, M.P.; Rukoyatkin, P.; Sans, J.L.; Sapozhnikov, M.G.; Sharov, V.; Shilov, S.; Shishov, Yu.; Sitnik, I.M.; Sorokin, P.V.; Spinka, H.; Sporov, E.A.; Strunov, L.N.; Svetov, A.; De Swart, J.J.; Telegin, Yu.P.; Tolmashov, I.; Trentalange, S.; Tsvinev, A.; Usov, Yu.A.; Vikhrov, V.V.; Whitten, C.A.; Zaporozhets, S.; Zarubin, A.; Zhdanov, A.A.; Zolin, L. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de Physique des Particules, de Physique Nucleaire et de l`Instrumentation Associee]|[I.V. Kurchatov Inst. of Atomic Energy, Moscow (Russian Federation)]|[Kharkov Inst. of Physics and Technology (Russian Federation)]|[Lab. of Nuclear Problems, JINR, Dubna (Russian Federation)]|[Lab. of High Energy Physics, JINR, Dubna (Russian Federation)]|[Lab. National SATURNE, CNRS, 91 - Gif-sur-Yvette (France)]|[Inst. of Physics, Belarus Academy of Sciences, Minsk (Belarus)]|[Dept. of Physics, Petersburg Nuclear Physics Inst., Gatchina (Russian Federation)

1995-03-01

A movable polarized proton target is planned to be installed in polarized beams of the Synchrophasotron-Nuclotron complex in order to carry out a spin physics experimental program at Dubna. The project is described and the first proposed experiments are discussed. ((orig.))

The movable polarized target as a basic equipment for high energy spin physics experiments at the JINR-Dubna accelerator complex

International Nuclear Information System (INIS)

Lehar, F.; Adiasevich, B.; Androsov, V.P.; Angelov, N.; Anischenko, N.; Antonenko, V.; Ball, J.; Baryshevsky, V.G.; Bazhanov, N.A.; Belyaev, A.A.; Benda, B.; Bodyagin, V.; Borisov, N.; Borzunov, Yu.; Bradamante, F.; Bunyatova, E.; Burinov, V.; Chernykh, E.; Combet, M.; Datskov, A.; Durand, G.; Dzyubak, A.P.; Fontaine, J.M.; Get'man, V.A.; Giorgi, M.; Golovanov, L.; Grebenyuk, V.; Grosnick, D.; Gurevich, G.; Hasegawa, T.; Hill, D.; Horikawa, N.; Igo, G.; Janout, Z.; Kalinnikov, V.A.; Karnaukhov, I.M.; Kasprzyk, T.; Khachaturov, B.A.; Kirillov, A.; Kisselev, Yu.; Kousmine, E.S.; Kovalenko, A.; Kovaljov, A.I.; Ladygin, V.P.; Lazarev, A.; Leconte, P.; Lesquen, A. de; Lukhanin, A.A.; Mango, S.; Martin, A.; Matafonov, V.N.; Matyushevsky, E.; Mironov, S.; Neganov, A.B.; Neganov, B.S.; Nomofilov, A.; Perelygin, V.; Plis, Yu.; Pilipenko, Yu.; Pisarev, I.L.; Piskunov, N.; Polunin, Yu.; Popkov, Yu.P.; Propov, A.A.; Prokofiev, A.N.; Rekalo, M.P.; Rukoyatkin, P.; Sans, J.L.; Sapozhnikov, M.G.; Sharov, V.; Shilov, S.; Shishov, Yu.; Sitnik, I.M.; Sorokin, P.V.; Spinka, H.; Sporov, E.A.; Strunov, L.N.; Svetov, A.; De Swart, J.J.; Telegin, Yu.P.; Tolmashov, I.; Trentalange, S.; Tsvinev, A.; Usov, Yu.A.; Vikhrov, V.V.; Whitten, C.A.; Zaporozhets, S.; Zarubin, A.; Zhdanov, A.A.; Zolin, L.

1995-01-01

A movable polarized proton target is planned to be installed in polarized beams of the Synchrophasotron-Nuclotron complex in order to carry out a spin physics experimental program at Dubna. The project is described and the first proposed experiments are discussed. ((orig.))

Breakdown of Hydrostatic Assumption in Tidal Channel with Scour Holes

Directory of Open Access Journals (Sweden)

Chunyan Li

2016-10-01

Full Text Available Hydrostatic condition is a common assumption in tidal and subtidal motions in oceans and estuaries.. Theories with this assumption have been largely successful. However, there is no definite criteria separating the hydrostatic from the non-hydrostatic regimes in real applications because real problems often times have multiple scales. With increased refinement of high resolution numerical models encompassing smaller and smaller spatial scales, the need for non-hydrostatic models is increasing. To evaluate the vertical motion over bathymetric changes in tidal channels and assess the validity of the hydrostatic approximation, we conducted observations using a vessel-based acoustic Doppler current profiler (ADCP. Observations were made along a straight channel 18 times over two scour holes of 25 m deep, separated by 330 m, in and out of an otherwise flat 8 m deep tidal pass leading to the Lake Pontchartrain over a time period of 8 hours covering part of the diurnal tidal cycle. Out of the 18 passages over the scour holes, 11 of them showed strong upwelling and downwelling which resulted in the breakdown of hydrostatic condition. The maximum observed vertical velocity was ~ 0.35 m/s, a high value in a tidal channel, and the estimated vertical acceleration reached a high value of 1.76×10-2 m/s2. Analysis demonstrated that the barotropic non-hydrostatic acceleration was dominant. The cause of the non-hydrostatic flow was the that over steep slopes. This demonstrates that in such a system, the bathymetric variation can lead to the breakdown of hydrostatic conditions. Models with hydrostatic restrictions will not be able to correctly capture the dynamics in such a system with significant bathymetric variations particularly during strong tidal currents.

Superconducting polarizing magnet for a movable polarized target

International Nuclear Information System (INIS)

Anishchenko, N.G.; Bartenev, V.D.; Blinov, N.A.

1998-01-01

The superconducting polarizing magnet was constructed for the JINR (Dubna) movable polarized target (MPT) with working volume 200 mm long and 30 mm in diameter. The magnet provides a polarizing magnetic field up to 6 T in the centre with the uniformity of 4.5 x 10 -4 in the working volume of the target. The magnet contains a main solenoidal winding 558 mm long and 206/144 mm in diameters, and compensating and correcting winding placed at its ends. The windings are made of a NbTi wire, impregnated with the epoxy resin and placed in the horizontal cryostat. The diameter of the 'warm' aperture of the magnet cryostat is 96 mm. The design and technology of the magnet winding are described. Results of the magnetic field map measurements, using a NMR-magnetometer are given. A similar magnet constructed at DAPNIA, CEA/Saclay (France), represented a model for the present development. The MPT array is installed in the beam line of polarized neutrons produced by break-up of polarized deuterons extracted from the synchrophasotron of the Laboratory of High Energies (LHE), JINR (Dubna)

Conceptual design report for a Fusion Engineering Device sector-handling machine and movable manipulator system

International Nuclear Information System (INIS)

Watts, K.D.; Masson, L.S.; McPherson, R.S.

1982-10-01

Design requirements, trade studies, design descriptions, conceptual designs, and cost estimates have been completed for the Fusion Engineering Device sector handling machine, movable manipulator system, subcomponent handling machine, and limiter blade handling machine. This information will be used by the Fusion Engineering Design Center to begin to determine the cost and magnitude of the effort required to perform remote maintenance on the Fusion Engineering Device. The designs presented are by no means optimum, and the costs estimates are rough-order-of-magnitude

Investigation of Scour Depth at Bridge Piers using Bri-Stars Model in Iran

OpenAIRE

Gh. Saeidifar; F. Raeiszadeh

2011-01-01

BRI-STARS (BRIdge Stream Tube model for Alluvial River Simulation) program was used to investigate the scour depth around bridge piers in some of the major river systems in Iran. Model calibration was performed by collecting different field data. Field data are cataloged on three categories, first group of bridges that their rivers bed are formed by fine material, second group of bridges that their rivers bed are formed by sand material, and finally bridges that their rivers bed a...

High magnetic field uniformity superconducting magnet for a movable polarized target

International Nuclear Information System (INIS)

Anishchenko, N.G.; Bartenev, V.D.; Blinov, N.A.

1998-01-01

The superconducting polarizing magnet was constructed for movable polarized target (MPT) with working volume 200 mm long and 30 mm in diameter. The magnet provides a polarizing magnetic field up to 6 T with the uniformity of 4.5 x 10 -4 in the working volume of the target. The magnet windings are made of a NbTi wire, impregnated with the epoxy resin and placed in the horizontal cryostat with 'warm' aperture diameter of 96 mm. The design and technology of the magnet winding are described. Results of the magnetic field map measurements using a NMR-magnetometer are given. The MPT set-up is installed in the beam line of polarized neutrons produced by break-up of polarized deuterons extracted from the Synchrophasotron of the Laboratory of High Energies (LHE), JINR, Dubna

Coronary angioscopy: a monorail angioscope with movable guide wire.

Science.gov (United States)

Nanto, S; Ohara, T; Mishima, M; Hirayama, A; Komamura, K; Matsumura, Y; Kodama, K

1991-03-01

A new angioscope was devised for easier visualization of the coronary artery. In its tip, the angioscope (Olympus) with an outer diameter of 0.8 mm had a metal lumen, through which a 0.014-in steerable guide wire passed. Using a 8F guiding catheter and a guide wire, it was introduced into the distal coronary artery. With injection of warmed saline through the guiding catheter, the coronary segments were visualized. In the attempted 70 vessels (32 left anterior descending [LAD], 10 right coronary [RCA], 28 left circumflex [LCX]) from 48 patients, 60 vessels (86%) were successfully examined. Twenty-two patients who underwent attempted examination of both LAD and LCX; both coronary arteries were visualized in 19 patients (86%). In the proximal site of the lesion, 40 patients have the diagonal branch or the obtuse marginal branch. In 34 patients (85%) the angioscope was inserted beyond these branches. In 12 very tortuous vessels, eight vessels (67%) were examined. In conclusion, the new monorail coronary angioscope with movable guide wire is useful to examine the stenotic lesions of the coronary artery.

Smart rocks and wireless communication system for real-time monitoring and mitigation of bridge scour : a proof-of-concept study.

Science.gov (United States)

2013-12-01

This study aims to integrate commercial measurement and communication components into a scour : monitoring system with magnets or electronics embedded in smart rocks, and evaluate and improve its : performance in laboratory and field conditions for t...

Quantum limits of photothermal and radiation pressure cooling of a movable mirror

International Nuclear Information System (INIS)

Pinard, M; Dantan, A

2008-01-01

We present a general quantum-mechanical theory for the cooling of a movable mirror in an optical cavity when both radiation pressure self-cooling and photothermal cooling effects are present, and show that these two mechanisms may bring the oscillator close to its quantum ground state, although in quite different regimes. Self-cooling caused by coherent exchange of excitations between the cavity mode and the mirror vibrational mode is shown to dominate in the good-cavity regime-when the mechanical resonance frequency is larger than the cavity decay rate, whereas photothermal-induced cooling can be made predominant in the bad-cavity limit. Both situations are compared, and the relevant physical quantities to be optimized in order to reach the lowest final excitation number states are extracted.

Movable Thomson scattering system based on optical fiber (TS-probe)

International Nuclear Information System (INIS)

Narihara, K.; Hayashi, H.

2009-01-01

This paper proposes a movable compact Thomson scattering (TS) system based on optical fibers (TS-probe). A TS-probe consists of a probe head, optical fiber, a laser-diode, polychromators and lock-in amplifiers. A laser beam optics and light collection optics are mounted rigidly on a probe head with a fixed scattering position. Laser light and scattered light are transmitted by flexible optical fibers, enabling us to move the TS-prove head freely during plasma discharge. The light signal scattered from an amplitude-modulated laser is detected against the plasma light based on the principle of the lock-in amplifier. With a modulated laser power of 300W, the scattered signal from a sheet plasma of 15 mm depth and n e -10 19 m -3 will be measured with 10% accuracy by setting the integrating time to 0.1 s. The TS-probe head is like a 1/20 model of the currently operating LHD-TS. (author)

Multi-dimensional rheology-based two-phase model for sediment transport and applications to sheet flow and pipeline scour

International Nuclear Information System (INIS)

Lee, Cheng-Hsien; Low, Ying Min; Chiew, Yee-Meng

2016-01-01

Sediment transport is fundamentally a two-phase phenomenon involving fluid and sediments; however, many existing numerical models are one-phase approaches, which are unable to capture the complex fluid-particle and inter-particle interactions. In the last decade, two-phase models have gained traction; however, there are still many limitations in these models. For example, several existing two-phase models are confined to one-dimensional problems; in addition, the existing two-dimensional models simulate only the region outside the sand bed. This paper develops a new three-dimensional two-phase model for simulating sediment transport in the sheet flow condition, incorporating recently published rheological characteristics of sediments. The enduring-contact, inertial, and fluid viscosity effects are considered in determining sediment pressure and stresses, enabling the model to be applicable to a wide range of particle Reynolds number. A k − ε turbulence model is adopted to compute the Reynolds stresses. In addition, a novel numerical scheme is proposed, thus avoiding numerical instability caused by high sediment concentration and allowing the sediment dynamics to be computed both within and outside the sand bed. The present model is applied to two classical problems, namely, sheet flow and scour under a pipeline with favorable results. For sheet flow, the computed velocity is consistent with measured data reported in the literature. For pipeline scour, the computed scour rate beneath the pipeline agrees with previous experimental observations. However, the present model is unable to capture vortex shedding; consequently, the sediment deposition behind the pipeline is overestimated. Sensitivity analyses reveal that model parameters associated with turbulence have strong influence on the computed results.

Development of a Computational Approach to Detect Instability and Incipient Motion of Large Riprap Rocks

Energy Technology Data Exchange (ETDEWEB)

Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Flora, K. [California Dept. of Transportation, Sacramento, CA (United States); Suaznabar, O. [Genex Systems, McLean, VA (United States); Shen, J [Genex Systems, McLean, VA (United States); Kerenyi, K [U.S. Dept. of Transportation, Washington, DC (United States)

2017-08-01

Local scour at bridge piers is a potential safety hazard of major concern to transportation agencies. If it is determined that scour at bridge piers can adversely affect the stability of a bridge, scour countermeasures to protect the pier should be considered.

Publicity in secured transactions law: Towards a European public notice filing system for non-possessory security rights in movable assets?

NARCIS (Netherlands)

Hamwijk, D.J.Y.

2014-01-01

There is a growing call to introduce a European public notice filing system for security rights in movable goods comparable to the notice filing system of Art. 9 UCC. A proposal to this effect has been adopted in Book IX DCFR, which represents a comprehensive framework of rules for proprietary

APPROACHES FOR STABILIZING OF BIPED ROBOTS IN A STANDING POSITION ON MOVABLE SUPPORT

Directory of Open Access Journals (Sweden)

D. N. Bazylev

2015-05-01

Full Text Available Subject of research. The problem of stabilization for biped walking robots on the surface is considered. The angle and angular velocity of the movable surface varies randomly in a limited range. Methods. Two approaches of stabilization of biped robots are proposed. The first approach requires the construction of kinematic and dynamic models of the robot. Dynamic equations were obtained using the Euler-Lagrange method. The control algorithm is based on the method of inverse dynamics, in which the original nonlinear dynamic model is linearized by a feedback. The second stabilization algorithm uses only the kinematic model of the robot. A hybrid controller is developed for this approach. In the case of low angular velocities of the movable support the robot stabilization is performed by PD controller on the basis of the angle error of deflection of the servo shaft. In the case of relatively high angular velocities of the support the controller also uses the gyroscope readings mounted in the robot torso. Maintenance of the robot’s gravity center over the center of bearing area for providing a stable position was chosen as a goal of control in both approaches. Main results. Efficiency and effectiveness of the proposed approaches for stabilization of biped robots on the moving surface are demonstrated by the numerical simulation. Both methods provide stability of the balancing robots on changing the angle of inclination and angular velocity of the moving surface in the ranges (50; 50 and (40 / sec; 40 / sec , respectively. Comparative analysis of these approaches under identical requirements for quality indicators of transients is also provided: transient time 0.2 sec п t  and overshoot   0%. The conditions under which each of the control methods will be more effective in practice are identified.

3D Traffic Scene Understanding From Movable Platforms.

Science.gov (United States)

Geiger, Andreas; Lauer, Martin; Wojek, Christian; Stiller, Christoph; Urtasun, Raquel

2014-05-01

In this paper, we present a novel probabilistic generative model for multi-object traffic scene understanding from movable platforms which reasons jointly about the 3D scene layout as well as the location and orientation of objects in the scene. In particular, the scene topology, geometry, and traffic activities are inferred from short video sequences. Inspired by the impressive driving capabilities of humans, our model does not rely on GPS, lidar, or map knowledge. Instead, it takes advantage of a diverse set of visual cues in the form of vehicle tracklets, vanishing points, semantic scene labels, scene flow, and occupancy grids. For each of these cues, we propose likelihood functions that are integrated into a probabilistic generative model. We learn all model parameters from training data using contrastive divergence. Experiments conducted on videos of 113 representative intersections show that our approach successfully infers the correct layout in a variety of very challenging scenarios. To evaluate the importance of each feature cue, experiments using different feature combinations are conducted. Furthermore, we show how by employing context derived from the proposed method we are able to improve over the state-of-the-art in terms of object detection and object orientation estimation in challenging and cluttered urban environments.

Study of technical and economical feasibility for implementation of a movable unit for treatment of industrial effluents with electron beam; Estudo de viabilidade tecnica e economica para implementacao de uma unidade movel para tratamento de efluentes industriais com feixe de eletrons

Energy Technology Data Exchange (ETDEWEB)

Rela, Carolina Sciamarelli

2006-07-01

The treatment of industrial effluents is a practice that is disseminating in accelerated rhythm, of contributing to reinforce the public image, through the combat of the pollution, it brings economical advantages allowing the companies the reuse of the treated water in their own processes. The liquid effluent treatment technique studied in the present work is the one that uses the chemical oxidation/reduction standing out the use of the electron beam (e.b.) radiation. This technique uses an advanced oxidation process, generating radicals highly reagents that provoke the oxidation, reduction, dissociation and degradation in composed organic and exercising lethal effect in general in the microorganisms and parasites. In this work a conceptual and basic project of a movable unit of effluents treatment using electron beam radiation process was developed, in order that the unit moves until the treatment point, where the effluent is produced, facilitating the logistics. A technical and economical feasibility study was also elaborated allowing data on the capacity and cost of effluents processing to consolidate the values of the necessary investments to be presented to foundations organs for the construction of a movable unit. The results of the studies demonstrated that it is technically viable attending the pertinent legislation of Brazil, in the aspects of Radiation Protection and transport limit capacity. The unitary cost of the e.b. radiation processing in the movable unit was shown more expensive than in the fixed unit, the reason is the decrease of the efficiency of the interaction of the incident electrons in the effluent, due to the reduction of electron energy operation time of the unit. (author)

River flooding and landscape changes impact ecological conditions of a scour hole lake in the Rhine-Meuse delta, The Netherlands

NARCIS (Netherlands)

Cremer, H.; Bunnik, F.P.M.; Donders, T.H.; Hoek, W.Z.; Koolen-Eekhout, M.; Koolmees, H.H.; Lavooi, E.

2010-01-01

A 400-year sediment record from an 18 m deep scour hole lake (Haarsteegse Wiel) near the Meuse River in the Netherlands was investigated for past changes in water quality, flooding frequency and landscape change using geophysical, geochemical and micropaleontological information. The results are

Potential effects of climate change on streambed scour and risks to salmonid survival in snow-dominated mountain basins

Science.gov (United States)

Jaime R. Goode; John M. Buffington; Daniele Tonina; Daniel J. Isaak; Russell F. Thurow; Seth Wenger; David Nagel; Charlie Luce; Doerthe Tetzlaff; Chris Soulsby

2013-01-01

Snowmelt-dominated basins in northern latitudes provide critical habitat for salmonids. As such, these systems may be especially vulnerable to climate change because of potential shifts in the frequency, magnitude, and timing of flows that can scour incubating embryos. A general framework is presented to examine this issue, using a series of physical models that link...

A Movable Phantom Design for Quantitative Evaluation of Motion Correction Studies on High Resolution PET Scanners

DEFF Research Database (Denmark)

Olesen, Oline Vinter; Svarer, C.; Sibomana, M.

2010-01-01

maximization algorithm with modeling of the point spread function (3DOSEM-PSF), and they were corrected for motions based on external tracking information using the Polaris Vicra real-time stereo motion-tracking system. The new automatic, movable phantom has a robust design and is a potential quality......Head movements during brain imaging using high resolution positron emission tomography (PET) impair the image quality which, along with the improvement of the spatial resolution of PET scanners, in general, raises the importance of motion correction. Here, we present a new design for an automatic...

Mechanical design control and implementation of a new movable intensity profile beamline monitor for the TRIUMF parity experiment 497

Science.gov (United States)

Ries, Thomas C.

1995-05-01

Two new movable beam intensity profile monitors have been installed into the TRIUMF Parity Experiment 497 Beamlines. Each unit serves two functions. Firstly, the beam median position, in a plane normal to the beam, is detected by split plate Secondary Emission Monitors. This information is used to lock the beam into the position of the movable monitor to within a few μm's via high band width ferrite core steering magnets operating in tandem in a closed loop servo feedback control system. Secondly, the beam profile and intensity is detected via a multi-wire secondary emission non-movable monitor, where the data provides high precision values regarding centroidal positions and profiles. The centroid position of the beam is statistically determined to an accuracy of ±10 μm from a data record length of 1 second. The design of each device adheres to strict standards of mechanically rigid construction. The split plate SEM accuracy and repeatability is better than 15 μm with an absolute resolution limit of 0.4 μm. Maximum travel is 2 inches in the vertical plane. Since the device is mechanically modular and both degrees of freedom are combined into a single mechanical unit, fast and easy handling is possible for maintenance in radioactive areas. The actuators are dc servo motors with tachometers driven by linear servo power amplifiers. These amplifiers are used in lieu of pulse width modulated amps to eliminate noise produced by the switching circuits. Position sensing is done by variable reluctance type absolute rotary encoders providing 16 bit resolution over the full range of travel. Positioning is done manually using a self centring potentiometer on the control panel that provides a ± velocity command signal to the power amplifiers. This configuration ensures good controllability over a very large range of positioning speeds hence making 0.4 μm incremental positioning possible, as well as, fast relocations over large relative distances. The precision movement

Delay time in a single barrier for a movable quantum shutter

International Nuclear Information System (INIS)

Hernandez, Alberto

2010-01-01

The transient solution and delay time for a δ potential scatterer with a movable quantum shutter is calculated by solving analytically the time-dependent Schroedinger equation. The delay time is analyzed as a function of the distance between the shutter and the potential barrier and also as a function of the distance between the potential barrier and the detector. In both cases, it is found that the delay time exhibits a dynamical behavior and that it tends to a saturation value Δt sat in the limit of very short distances, which represents the maximum delay produced by the potential barrier near the interaction region. The phase time τ θ , on the other hand, is not an appropriate time scale for measuring the time delay near the interaction region, except if the shutter is moved far away from the potential. The role played by the antibound state of the system on the behavior of the delay time is also discussed.

Long-term monitoring of streambed sedimentation and scour in a dynamic stream based on streambed temperature time series.

Science.gov (United States)

Sebok, Eva; Engesgaard, Peter; Duque, Carlos

2017-08-24

This study presented the monitoring and quantification of streambed sedimentation and scour in a stream with dynamically changing streambed based on measured phase and amplitude of the diurnal signal of sediment temperature time series. With the applied method, changes in streambed elevation were estimated on a sub-daily scale with 2-h intervals without continuous maintenance of the measurement system, thus making both high temporal resolution and long-term monitoring of streambed elevations possible. Estimates of streambed elevation showed that during base flow conditions streambed elevation fluctuates by 2-3 cm. Following high stream stages, scouring of 2-5 cm can be observed even at areas with low stream flow and weak currents. Our results demonstrate that weather variability can induce significant changes in the stream water and consequently sediment temperatures influencing the diurnal temperature signal in such an extent that the sediment thickness between paired temperature sensors were overestimated by up to 8 cm. These observations have significant consequences on the design of vertical sensor spacing in high-flux environments and in climates with reduced diurnal variations in air temperature.

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

Scour around bridge pier is the main reason for the failure of bridges. The local scour around the pier causes exposure of the foundation and may lead to undermining of the structure. Different types of protection measures such as the provision of raft, apron, sheet piles, etc. can be used as scour protectionmeasures. One of ...

Influence of air scouring on the performance of a Self Forming Dynamic Membrane BioReactor (SFD MBR) for municipal wastewater treatment.

Science.gov (United States)

Salerno, Carlo; Vergine, Pompilio; Berardi, Giovanni; Pollice, Alfieri

2017-01-01

The Membrane BioReactor (MBR) is a well-established filtration-based technology for wastewater treatment. Despite the high quality of the effluent produced, one of the main drawbacks of the MBR is membrane fouling. In this context, a possible evolution towards systems having potentially lower installation and operating costs is the Self Forming Dynamic Membrane BioReactor (SFD MBR). Key of this technology is the self-formation of a biological filtering layer on a support of inert material. In this work, a lab-scale aerobic SFD MBR equipped with a nylon mesh was operated at approximately 95Lm -2 h -1 . Two mesh pore sizes (20 and 50μm) and three air scouring flow rates (150, 250, and 500mL air min -1 ) were tested at steady state. Under all the tested conditions, the SFD MBR effectively treated real municipal wastewater. The quality of the produced effluent increased for lower mesh size and lower air scouring intensity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Three Dimensional Analysis of Pier Extension and Guide Wall Design Alternatives to Mitigate Local Scour Risk at the BNSF Railroad Bridge Downstream of the Prado Dam

Energy Technology Data Exchange (ETDEWEB)

Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Sinha, N. [Argonne National Lab. (ANL), Argonne, IL (United States); Kerenyi, K [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-03-01

The primary objectives of the computational fluid dynamics (CFD) analysis are (1) to verify that the design concept of using wedge shaped pier extensions to divert flow around piers as a scour counter measure has the intended effect on the flow, (2) to refine the design of the length and orientation of the pier extensions within the channel and (3) to optimize the guide walls that will protect a set of outer piers and the abutments on each side of the channel. The original proposed design is shown in Figure 1.3. The results of this effort are the recommended designs that are judged to be the best designs based on results from the set of test cases run combined with engineering judgment. The refined designs from the CFD analysis are expected to be tested in a limited set of physical model experiments to verify that they work well.

Rock stream stability structures in the vicinity of bridges.

Science.gov (United States)

2014-10-01

This report was sponsored by the Utah Department of Transportation (UDOT) to determine if rock stream stability structures could be used as : scour countermeasures and to protect streambanks. Traditional scour countermeasures, such as rock riprap, ar...

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.

Science.gov (United States)

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...

3-D flow and scour near a submerged wing dike: ADCP measurements on the Missouri River

Science.gov (United States)

Jamieson, E.C.; Rennie, C.D.; Jacobson, R.B.; Townsend, R.D.

2011-01-01

Detailed mapping of bathymetry and three-dimensional water velocities using a boat-mounted single-beam sonar and acoustic Doppler current profiler (ADCP) was carried out in the vicinity of two submerged wing dikes located in the Lower Missouri River near Columbia, Missouri. During high spring flows the wing dikes become submerged, creating a unique combination of vertical flow separation and overtopping (plunging) flow conditions, causing large-scale three-dimensional turbulent flow structures to form. On three different days and for a range of discharges, sampling transects at 5 and 20 m spacing were completed, covering the area adjacent to and upstream and downstream from two different wing dikes. The objectives of this research are to evaluate whether an ADCP can identify and measure large-scale flow features such as recirculating flow and vortex shedding that develop in the vicinity of a submerged wing dike; and whether or not moving-boat (single-transect) data are sufficient for resolving complex three-dimensional flow fields. Results indicate that spatial averaging from multiple nearby single transects may be more representative of an inherently complex (temporally and spatially variable) three-dimensional flow field than repeated single transects. Results also indicate a correspondence between the location of calculated vortex cores (resolved from the interpolated three-dimensional flow field) and the nearby scour holes, providing new insight into the connections between vertically oriented coherent structures and local scour, with the unique perspective of flow and morphology in a large river.

Multiscale modeling of porous ceramics using movable cellular automaton method

Science.gov (United States)

Smolin, Alexey Yu.; Smolin, Igor Yu.; Smolina, Irina Yu.

2017-10-01

The paper presents a multiscale model for porous ceramics based on movable cellular automaton method, which is a particle method in novel computational mechanics of solid. The initial scale of the proposed approach corresponds to the characteristic size of the smallest pores in the ceramics. At this scale, we model uniaxial compression of several representative samples with an explicit account of pores of the same size but with the unique position in space. As a result, we get the average values of Young's modulus and strength, as well as the parameters of the Weibull distribution of these properties at the current scale level. These data allow us to describe the material behavior at the next scale level were only the larger pores are considered explicitly, while the influence of small pores is included via effective properties determined earliar. If the pore size distribution function of the material has N maxima we need to perform computations for N-1 levels in order to get the properties step by step from the lowest scale up to the macroscale. The proposed approach was applied to modeling zirconia ceramics with bimodal pore size distribution. The obtained results show correct behavior of the model sample at the macroscale.

Eco toxicological assessment of the usage of chemical meliorants and fertilizers on the content of movable fluorine in humus shallow solonetz of the Northern Kazakhstan

International Nuclear Information System (INIS)

Sarsenova, A.A.; Ermokhin, Yu.I.; Kazantsev, N.Ya.

2008-01-01

The aim of present research is the assessment of the ecological rate setting of chemical meliorants and fertilizers using for melioration of solonetz. The scientific problem of work is the study of influence of chemical meliorants, phosphogypsum doses and nitrogen fertilizer on the content of movable fluorine in soil.

应用新型煮练酶SKQ-45的散棉低温煮漂工艺优化%Application of novel scouring enzyme SKQ-45 in low temperature scouring and bleaching for loose cotton and its optimization

Institute of Scientific and Technical Information of China (English)

陈诚; 贾丽霞; 张梦婉; 何鹰

2016-01-01

Low temperature scouring and bleaching processes for loose cotton were carried out with scouring enzyme KQ-45 (SKQ-45), a type of novel low temperature catalytic auxiliary for hydrogen peroxide. Based on single factor analysis, the effects and optimization range of SKQ-45 dosage, temperature and time on the bundle strength and whiteness of loose cotton were discussed. The low temperature process with SKQ-45 was optimized by three-factor quadratic general rotary unitized design, and the experimental data was analyzed in DPS data processing system. The optimum process was determined as fol ows: SKQ-45 3.9 g/L, 36% H2O2 6.0 g/L, NaOH 2.0 g/L, bath ratio 1∶40, scoured at 54 ℃ for 55 min. The whiteness of loose cotton treated by the optimal process was 63.40%, which was higher than the high temperature alkali scour⁃ing and bleaching process. The bundle strength after scouring and dyeing was 1 774.56 and 1 599.64 cN, which increased 67.30% and 100.34% than the high temperature process, respectively. The K/S value and the fixation rate of dyed loose cotton increased 11.54% and 9.32%, respectively. Accordingly, the souring and bleaching result of SKQ-45 process was better than the high temperature process.%采用一种新型复合酶制剂——双氧水低温催化煮练酶KQ-45（SKQ-45）对散棉进行低温煮漂处理，在单因素分析的基础上讨论了SKQ-45用量、煮漂温度和时间对散棉断裂强力及白度的影响及优化范围，然后利用3因子2次通用旋转组合设计对SKQ-45低温煮漂工艺进行优化，并将优化数据在DPS数据处理系统中运行分析，从而得到SKQ-45煮漂的优化工艺：SKQ-453.9 g/L，36%H2O26.0 g/L，NaOH 2.0 g/L，温度54℃，时间55 min，浴比1∶40。经优化工艺处理的散棉白度达到了63.40%，高于高温碱煮漂工艺；煮漂后断裂强力及染后2次断裂强力分别为1774.56和1599.64 cN，较高温工艺分别提高了67.30%和100.34%�

Recommendations concerning guide-lines in radiation protection in hospitals and policlinics

International Nuclear Information System (INIS)

1985-01-01

This report is intended as a practical safety manual and reference book for applications of ionizing radiation in hospitals and out-patients' departments. It is written for use by persons, responsible, in whatever capacity, for radiological protection. The first chapter outlines the risks of ionizing radiation and the Dutch legislation in this respect. The following five chapters deal with the use of different types of radiation sources. (Conventional X-ray apparatus and megavolt instruments like linear accelerators, fixed encapsulated sources, movable fixed sources and open sources). The report is concluded with an explanation of terms and appendices that contain practical information (addresses, tables, official directives). (orig.)

Commissioning of the SPARC Movable Emittance Meter and Its First Operation at PITZ

CERN Document Server

Catani, L; Cianchi, A

2005-01-01

For the SPARC Project a novel diagnostic device, called "Emittance-meter", has been conceived and constructed to perform a detailed study of the emittance compensation process in the SPARC photo-injector and to optimize the RF-gun and the accelerator working point. It consists of a movable emittance measurement system, based on the 1D pepper-pot method, installed between two long bellows with the possibility to scan a region 1.5 m long downstream the RF-gun. The construction of the device was completed in the first part of this year and a series of laboratory tests, to evaluate its performances, were carried out in Spring 2005. At the beginning of the summer the complete system was moved to DESY at Zeuthen to be installed on the Photo Injector Test Facility PITZ. After the commissioning it will used for measurements of the PITZ electron beam in the framework of a collaboration between the SPARC and PITZ Projects aiming on studies and operations with photo injectors.

3D simulation of friction stir welding based on movable cellular automaton method

Science.gov (United States)

Eremina, Galina M.

2017-12-01

The paper is devoted to a 3D computer simulation of the peculiarities of material flow taking place in friction stir welding (FSW). The simulation was performed by the movable cellular automaton (MCA) method, which is a representative of particle methods in mechanics. Commonly, the flow of material in FSW is simulated based on computational fluid mechanics, assuming the material as continuum and ignoring its structure. The MCA method considers a material as an ensemble of bonded particles. The rupture of interparticle bonds and the formation of new bonds enable simulations of crack nucleation and healing as well as mas mixing and microwelding. The simulation results showed that using pins of simple shape (cylinder, cone, and pyramid) without a shoulder results in small displacements of plasticized material in workpiece thickness directions. Nevertheless, the optimal ratio of longitudinal velocity to rotational speed makes it possible to transport the welded material around the pin several times and to produce a joint of good quality.

Performing Free Radioactive Certificate as an Effort to Protect Import and Export Commodities in Globalization Era

International Nuclear Information System (INIS)

Kunto-Wiharto; Syarbaini

2001-01-01

Several activities such as nuclear weapon tests, nuclear fuel reprocessing and nuclear accidents have caused radioactive contamination in local, regional and global environment. In globalization and free trade era, every country will be faced to the condition with the movable commodities from and to another countries. Global contamination through import and export commodities is a problem will be found every country in the future. Therefore, performing free radioactive certification on import and export commodities must be carried out to protect a member of public and environment from radioactive contamination. (author)

a Movable Charging Unit for Green Mobility

Science.gov (United States)

ElBanhawy, E. Y.; Nassar, K.

2013-05-01

Battery swapping of electric vehicles (EVs) matter appears to be the swiftest and most convenient to users. The existence of swapping stations increases the feasibility of distributed energy storage via the electric grid. However, it is a cost-prohibitive way of charging. Early adaptors' preferences of /perceptions about EV system in general, has its inflectional effects on potential users hence the market penetration level. Yet, the charging matter of electric batteries worries the users and puts more pressure on them with the more rigorous planning-ahead they have to make prior to any trip. This paper presents a distinctive way of charging. It aims at making the overall charging process at ease. From a closer look into the literature, most of EVs' populations depend on domestic charge. Domestic charging gives them more confidence and increases the usability factor of the EV system. Nevertheless, they still need to count on the publically available charging points to reach their destination(s). And when it comes to multifamily residences, it becomes a thorny problem as these apartments do not have a room for charging outlets. Having said the irritating charging time needed to fatten the batteries over the day and the minimal average mileage drove daily, hypothetically, home delivery charging (Movable Charging Unit-MCU) would be a stupendous solution. The paper discusses the integration of shortest path algorithm problem with the information about EV users within a metropolitan area, developing an optimal route for a charging unit. This MCU delivers charging till homes whether by swapping batteries or by fast charging facility. Information about users is to be provided by the service provider of the neighbourhood, which includes charging patterns (timing, power capacity). This problem lies under the shortest path algorithms problem. It provides optimal route of charging that in return shall add more reliability and usability values and alleviate the charging

Scour Protection of Off-Shore Windmills

DEFF Research Database (Denmark)

Frigaard, Peter; Pedersen, Jan

2002-01-01

In the Eighties and Nineties wind turbines with a total rated power of app 1000 Mega watt were erected in Denmark. Today more that 13% of the electrical consumption in in Denmark is covered by electricity from wind turbines. Through, due to lack of good positions for the windmills and due...... to growing opposition against the the wind turbines, the Danish government initiated in 1999 the construction of several large off-shore wind farms....

Novel method for the preparation of core-shell nanoparticles with movable Ag core and polystyrene loop shell

International Nuclear Information System (INIS)

Liu Weijun; Zhang Zhicheng; He Weidong; Zheng Cheng; Ge Xuewu; Li, Jian; Liu Huarong; Jiang Hao

2006-01-01

Core/shell nanoparticles with movable silver (Ag) core and polystyrene (PSt) shell (Ag at PSt nanoparticle) were successfully synthesized at room temperature and under ambient pressure via two steps: γ-irradiation and interfacial-initiated polymerization. Firstly, mono-dispersed Ag nanoparticles with diameters 20 nm were synthesized in inversed microemulsion by reducing silver nitrate under γ-irradiation. Then, Ag nanoparticles were coated with PSt via interfacial-initiated polymerization with cumene hydroperoxide/ferrous sulfate/disodium ethylenediaminetetraacetate/sodium formaldehyde sulfoxylate (CHPO-Fe 2+ -EDTA-SFS) as the redox initiation pair. The resulted Ag at PSt nanoparticles were identified by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS)

Multiscale Simulation of Porous Ceramics Based on Movable Cellular Automaton Method

Science.gov (United States)

Smolin, A.; Smolin, I.; Eremina, G.; Smolina, I.

2017-10-01

The paper presents a model for simulating mechanical behaviour of multiscale porous ceramics based on movable cellular automaton method, which is a novel particle method in computational mechanics of solid. The initial scale of the proposed approach corresponds to the characteristic size of the smallest pores in the ceramics. At this scale, we model uniaxial compression of several representative samples with an explicit account of pores of the same size but with the random unique position in space. As a result, we get the average values of Young’s modulus and strength, as well as the parameters of the Weibull distribution of these properties at the current scale level. These data allow us to describe the material behaviour at the next scale level were only the larger pores are considered explicitly, while the influence of small pores is included via the effective properties determined at the previous scale level. If the pore size distribution function of the material has N maxima we need to perform computations for N - 1 levels in order to get the properties from the lowest scale up to the macroscale step by step. The proposed approach was applied to modelling zirconia ceramics with bimodal pore size distribution. The obtained results show correct behaviour of the model sample at the macroscale.

Controller Design and Experiment for Tracking Mount of Movable SLR, ARGO-M

Directory of Open Access Journals (Sweden)

Cheol Hoon Park

2012-04-01

Full Text Available Controller design procedure for prototype tracking mount of Movable SLR (Satellite Laser Ranging, ARGO-M is presented. Tracking mount of ARGO-M is altitude-azimuth type and it has two axes of elevation and azimuth to control its position. Controller consists of velocity and acceleration feed-forward controller, position controller at outer loop, velocity controller at inner loop. There are two kinds of position control modes. One is the pointing mode to move from one position to the other position as fast as possible and the other one is tracking mode to follow SLR trajectory as precise as possible. Because the requirement of tracking accuracy is less than 5 arcsec and it is very tight error budget, a sophisticated controller needs to be prepared to meet the accuracy. Especially, ARGO-M is using the cross-roller bearing at each axis to increase the mechanical accuracy, which requires add-on controller DOB (Disturbance observer to suppress friction load and low frequency disturbances. The pointing and tracking performance of the designed controller is simulated and visualized using MATLAB/ Simulink and SimMechanics and the experimental results using test are presented as well.

A Labeling Model Based on the Region of Movability for Point-Feature Label Placement

Directory of Open Access Journals (Sweden)

Lin Li

2016-09-01

Full Text Available Automatic point-feature label placement (PFLP is a fundamental task for map visualization. As the dominant solutions to the PFLP problem, fixed-position and slider models have been widely studied in previous research. However, the candidate labels generated with these models are set to certain fixed positions or a specified track line for sliding. Thus, the whole surrounding space of a point feature is not sufficiently used for labeling. Hence, this paper proposes a novel label model based on the region of movability, which comes from plane collision detection theory. The model defines a complete conflict-free search space for label placement. On the premise of no conflict with the point, line, and area features, the proposed model utilizes the surrounding zone of the point feature to generate candidate label positions. By combining with heuristic search method, the model achieves high-quality label placement. In addition, the flexibility of the proposed model enables placing arbitrarily shaped labels.

Fire protection countermeasures for containment ventilation systems

International Nuclear Information System (INIS)

Alvares, N.; Beason, D.; Bergman, V.; Creighton, J.; Ford, H.; Lipska, A.

1980-01-01

The goal of this project is to find countermeasures to protect High Efficiency Particulate Air (HEPA) filters, in exit ventilation ducts, from the heat and smoke generated by fire. Initially, methods were developed to cool fire-heated air by fine water spray upstream of the filters. It was recognized that smoke aerosol exposure to HEPA filters could also cause disruption of the containment system. Through testing and analysis, several methods to partially mitigate the smoke exposure to the HEPA filters were identified. A continuous, movable, high-efficiency prefilter using modified commercial equipment was designed. The technique is capable of protecting HEPA filters over the total time duration of the test fires. The reason for success involved the modification of the prefiltration media. Commercially available filter media has particle sorption efficiency that is inversely proportional to media strength. To achieve properties of both efficiency and strength, rolling filter media were laminated with the desired properties. The approach was Edisonian, but truncation in short order to a combination of prefilters was effective. The application of this technique was qualified, since it is of use only to protect HEPA filters from fire-generated smoke aerosols. It is not believed that this technique is cost effective in the total spectrum of containment systems, especially if standard fire protection systems are available in the space. But in areas of high-fire risk, where the potential fuel load is large and ignition sources are plentiful, the complication of a rolling prefilter in exit ventilation ducts to protect HEPA filters from smoke aerosols is definitely justified

A knowledge-based control system for air-scour optimisation in membrane bioreactors.

Science.gov (United States)

Ferrero, G; Monclús, H; Sancho, L; Garrido, J M; Comas, J; Rodríguez-Roda, I

2011-01-01

Although membrane bioreactors (MBRs) technology is still a growing sector, its progressive implementation all over the world, together with great technical achievements, has allowed it to reach a mature degree, just comparable to other more conventional wastewater treatment technologies. With current energy requirements around 0.6-1.1 kWh/m3 of treated wastewater and investment costs similar to conventional treatment plants, main market niche for MBRs can be areas with very high restrictive discharge limits, where treatment plants have to be compact or where water reuse is necessary. Operational costs are higher than for conventional treatments; consequently there is still a need and possibilities for energy saving and optimisation. This paper presents the development of a knowledge-based decision support system (DSS) for the integrated operation and remote control of the biological and physical (filtration and backwashing or relaxation) processes in MBRs. The core of the DSS is a knowledge-based control module for air-scour consumption automation and energy consumption minimisation.

Fire protection countermeasures for containment ventilation systems

International Nuclear Information System (INIS)

Alvares, N.J.; Beason, D.G.; Bergman, W.; Ford, H.W.; Lipska, A.E.

1980-01-01

The goal of this project is to find countermeasures to protect HEPA filters in exit ventilation ducts from the heat and smoke generated by fire. Several methods for partially mitigating the smoke exposure to the HEPA filters were identified through testing and analysis. These independently involve controlling the fuel, controlling the fire, and intercepting the smoke aerosol prior to its sorption on the HEPA filter. Exit duct treatment of aerosols is not unusual in industrial applications and involves the use of scrubbers, prefilters, and inertial impaction, depending on the size, distribution, and concentration of the subject aerosol. However, when these unmodified techniques were applied to smoke aerosols from fires on materials, common to experimental laboratories of LLNL, it was found they offered minimal protection to the HEPA filters. Ultimately, a continuous, movable, high-efficiency prefilter using modified commercial equipment was designed. This technique is capable of protecting HEPA filters over the total duration of the test fires. The reason for success involved the modificaton of the prefiltration media. Commercially available filter media has a particle sorption efficiency that is inversely proportional to media strength. To achieve properties of both efficiency and strength, we laminated rolling filter media with the desired properties. It is not true that the use of rolling prefilters solely to protect HEPA filters from fire-generated smoke aerosols is cost effective in every type of containment system, especially if standard fire-protection systems are available in the space. But in areas of high fire risk, where the potential fuel load is large and ignition sources are plentiful, the complication of a rolling prefilter in exit ventilation ducts to protect HEPA filters from smoke aerosols is definitely justified

The research and development of inclination angle magnetic fluid detector with a movable sensing element based on permanent magnets

Energy Technology Data Exchange (ETDEWEB)

Lagutkina, D.Yu., E-mail: Lagutkina_D@mail.ru; Saikin, M.S., E-mail: saikinms@mail.ru

2017-06-01

The article presents an account on some new designs, which have been developed for the magnetic fluid sensor with a movable sensor based on permanent magnets with the support of Ivanovo State Power Engineering University. The research carried out is aimed at elucidating the influence of the detector sensing element on its operating performance. - Highlights: • In order to conduct a careful research of IAMFD designs operating performance the algorithm was applied to look into the SE suspension force dependencies on its spatial position. • According to this algorithm, the value of the sensitive element suspension force is obtained with use of the MF attraction force of the to the permanent magnet.

Method and system having ultrasonic sensor movable by translation device for ultrasonic profiling of weld samples

Science.gov (United States)

Panyard, James; Potter, Timothy; Charron, William; Hopkins, Deborah; Reverdy, Frederic

2010-04-06

A system for ultrasonic profiling of a weld sample includes a carriage movable in opposite first and second directions. An ultrasonic sensor is coupled to the carriage to move over the sample as the carriage moves. An encoder determines the position of the carriage to determine the position of the sensor. A spring is connected at one end of the carriage. Upon the carriage being moved in the first direction toward the spring such that the carriage and the sensor are at a beginning position and the spring is compressed the spring decompresses to push the carriage back along the second direction to move the carriage and the sensor from the beginning position to an ending position. The encoder triggers the sensor to take the ultrasonic measurements of the sample when the sensor is at predetermined positions while the sensor moves over the sample between the beginning and positions.

Book as movable cultural heritage on the DEDI portal: the place of the book in the Digital encyclopaedia of Slovenian natural and cultural heritage

Directory of Open Access Journals (Sweden)

Ines Jerele

2010-01-01

Full Text Available The project entitled "Digital encyclopaedia of Slovenian natural and cultural heritage" (DEDI II has been evolved as a prototype research and development project (2009-2010. It represents the first attempt of multimedia-rich digital representation of Slovenian natural and cultural heritage by the means of interdisciplinary work of different cultural and educational institutions. Verifiable, qualitative and complex content of four types of heritage is co-located on a common site (immovable, movable, vivid and natural heritage with the goal to promote the heritage and educate the general public, as well as to encourage the public to create tomorrow’s heritage. A new detailed thesaurus was constructed enabling the classification of different kinds of heritage.It merges the established and newly created taxonomies of each type of heritage.To ensure the quality of published contents, the professional Editorial Board has been established. The National and University Library of Slovenia (NUK, one of the fundamental institutions for collecting and keeping the written cultural heritage of Slovenia, has already participated in the conception of the first project scheme. In the second part of the DEDI project, NUK contributed a number of digitalized books selected on the basis of their historical and literary importance. Digitalized books were published on the DEDI portal under the movable cultural heritage taxonomy

ICI system for protecting underwater structures

Energy Technology Data Exchange (ETDEWEB)

1977-10-14

The new ICI Offshore product consists of polypropylene fibers about 4.4 m long, and with a density lower than that of sea water and thus a good buoyancy coefficient. Bundles of the fibers are passed through a braided mat of polyester, ''Paraweb'', which is weighted in accordance with the density of the entire system. The system is installed at the foot of platform legs and axially along pipelines to prevent scouring by ocean currents. The system has been installed in 144.8 m of water along the pipeline linking the Piper field to the Flotta terminal in the Orkney Islands. By reducing the velocity of the marine currents, the system causes sand and other material to be deposited along the fibers, forming a protective ''talus'' cone at first, then completely covering the structure. A sizable sand deposit had accumulated along the test segment of the pipeline less than one month after installation of the system. Use of the system on the Ekofisk-Emden gas pipeline where it is uncovered in the Danish North Sea sector is proposed.

Protecting LHC components against radiation resulting from an unsynchronized beam abort

International Nuclear Information System (INIS)

Mokhov, Nikolai V.

2001-01-01

The effect of possible accidental beam loss in the LHC on the IP5 and IP6 insertion elements is studied via realistic Monte Carlo simulations. The scenario studied is beam loss due to unsynchronized abort at an accidental prefire of one of the abort kicker modules. Simulations show that this beam loss would result in severe heating of the IP5 and IP6 superconducting (SC) quadrupoles. Contrary to the previous considerations with a stationary set of collimators in IP5, collimators in IP6 close to the cause are proposed: a movable collimator upstream of the Q4 quadrupole and a stationary one upstream of the extraction septumMSD. The calculated temperature rise in the optimal set of collimators is quite acceptable. All SC magnets are protected by these collimators against damage

Protecting LHC Components Against Radiation Resulting From an Unsynchronized Beam Abort

CERN Document Server

Drozhdin, A I; Mokhov, N V; Rakhno, I L; Weisse, E

2001-01-01

The effect of possible accidental beam loss in the LHC on the IP5 and IP6 insertion elements is studied via realistic Monte Carlo simulations. The scenario studied is beam loss due to unsynchronized abort at an accidental prefire of one of the abort kicker modules. Simulations show that this beam loss would result in severe heating of the IP5 and IP6 superconducting (SC) quadrupoles. Contrary to the previous considerations with a stationary set of collimators in IP5, collimators in IP6 close to the cause are proposed: a movable collimator upstream of the Q4 quadrupole and a stationary one upstream of the extraction septum MSD. The calculated temperature rise in the optimal set of collimators is quite acceptable. All SC magnets are protected by these collimators against damage.

Age determination of the world’s oldest movable metal types through measuring the “meog” using AMS

Energy Technology Data Exchange (ETDEWEB)

Hong, W., E-mail: whong@kigam.re.kr [Geochemical Analysis Center, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124 Gwahang-no, Yuseong-gu, Daejeon 305-350 (Korea, Republic of); Department of Accelerator and Beam Nano Engineering, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Lee, S.C. [Cheongju Early Printing Museum, 866 Uncheon-dong, Hongdeok-gu, Cheongju, Chungbuk (Korea, Republic of); Park, J.H.; Park, G. [Geochemical Analysis Center, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124 Gwahang-no, Yuseong-gu, Daejeon 305-350 (Korea, Republic of); Sung, K.H. [Geochemical Analysis Center, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124 Gwahang-no, Yuseong-gu, Daejeon 305-350 (Korea, Republic of); Department of Accelerator and Beam Nano Engineering, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Lee, J.G. [Geochemical Analysis Center, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124 Gwahang-no, Yuseong-gu, Daejeon 305-350 (Korea, Republic of); Nam, K.H. [Department of Library and Information Science, Kyungpook National University, 67 Kyungdaejungmun-no, Buk-gu, Daegu 702-701 (Korea, Republic of)

2015-10-15

The fabrication year of a set of movable metal types that were thought to be used for printing “Jeungdoga” was investigated. Since the types were made from bronze and did not contain carbon, an organic black ink called “meog” was collected from the type surfaces to quantify their ages. The meog samples were collected from 34 metal types, and 27 ages were obtained. The youngest age was 798 ± 44 yrBP, and the oldest reasonable age was 1166 ± 43 yrBP. The weighted average after eliminating ages with poor statistics was 950 ± 28 yrBP. This age is 300 years older than that of the Jikji (AD 1377), which is a Buddhist document recognized as the world’s oldest document printed using metal types, and also older than that of the Gutenberg bible (AD 1450).

Age determination of the world’s oldest movable metal types through measuring the “meog” using AMS

International Nuclear Information System (INIS)

Hong, W.; Lee, S.C.; Park, J.H.; Park, G.; Sung, K.H.; Lee, J.G.; Nam, K.H.

2015-01-01

The fabrication year of a set of movable metal types that were thought to be used for printing “Jeungdoga” was investigated. Since the types were made from bronze and did not contain carbon, an organic black ink called “meog” was collected from the type surfaces to quantify their ages. The meog samples were collected from 34 metal types, and 27 ages were obtained. The youngest age was 798 ± 44 yrBP, and the oldest reasonable age was 1166 ± 43 yrBP. The weighted average after eliminating ages with poor statistics was 950 ± 28 yrBP. This age is 300 years older than that of the Jikji (AD 1377), which is a Buddhist document recognized as the world’s oldest document printed using metal types, and also older than that of the Gutenberg bible (AD 1450).

Electromechanical model to predict the movability of liquids in an electrowetting-on-dielectric microfluidic device

Science.gov (United States)

Torabinia, Matin; Farzbod, Ali; Moon, Hyejin

2018-04-01

In electrowetting-on-dielectric (EWOD) microfluidics, a motion of a fluid is created by a voltage applied to the fluid/surface interface. Water and aqueous solutions are the most frequently used fluids in EWOD devices. In order for EWOD microfluidics to be a versatile platform for various applications, however, movability of different types of fluids other than aqueous solutions should be understood. An electromechanical model using a simple RC circuit has been used to predict the mechanical force exerted on a liquid droplet upon voltage application. In this present study, two important features missed in previous works are addressed. Energy dissipation by contact line friction is considered in the new model as the form of resistor. The phase angle is taken into account in the analysis of the AC circuit. The new electromechanical model and computation results are validated with experimental measurements of forces on two different liquids. The model is then used to explain influences of contact angle hysteresis, surface tension, conductivity, and dielectric constant of fluids to the mechanical force on a liquid droplet.

Active and passive kink mode studies in a tokamak with a movable ferromagnetic wall

Energy Technology Data Exchange (ETDEWEB)

Levesque, J. P.; Hughes, P. E.; Bialek, J.; Byrne, P. J.; Mauel, M. E.; Navratil, G. A.; Peng, Q.; Rhodes, D. J.; Stoafer, C. C. [Department of Applied Physics and Applied Mathematics, Columbia University, 500 W. 120th Street, New York, New York 10027 (United States)

2015-05-15

High-resolution active and passive kink mode studies are conducted in a tokamak with an adjustable ferromagnetic wall near the plasma surface. Ferritic tiles made from 5.6 mm thick Hiperco{sup ®} 50 alloy have been mounted on the plasma-facing side of half of the in-vessel movable wall segments in the High Beta Tokamak-Extended Pulse device [D. A. Maurer et al., Plasma Phys. Controlled Fusion 53, 074016 (2011)] in order to explore ferritic resistive wall mode stability. Low-activation ferritic steels are a candidate for structural components of a fusion reactor, and these experiments examine MHD stability of plasmas with nearby ferromagnetic material. Plasma-wall separation for alternating ferritic and non-ferritic wall segments is adjusted between discharges without opening the vacuum vessel. Amplification of applied resonant magnetic perturbations and plasma disruptivity are observed to increase when the ferromagnetic wall is close to plasma surface instead of the standard stainless steel wall. Rapidly rotating m/n=3/1 external kink modes have higher growth rates with the nearby ferritic wall. Feedback suppression of kinks is still as effective as before the installation of ferritic material in vessel, in spite of increased mode growth rates.

Virtuelle ting

DEFF Research Database (Denmark)

Mathiasen, Peter Dueholm

2014-01-01

In the article it is discussed whether virtual items can be described as "rørlige ting” (movable objects) and therefore subject to protection against e.g. theft under the Danish Criminal Code. Norwegian, Swedish and Dutch criminal laws are included in the article.......In the article it is discussed whether virtual items can be described as "rørlige ting” (movable objects) and therefore subject to protection against e.g. theft under the Danish Criminal Code. Norwegian, Swedish and Dutch criminal laws are included in the article....

Electrodeposition of nickel onto steel, using a thermostatic cell and movable anode by a variable current.; Electrodeposicion de niquel sobre acero al carbon, empleando una celda termostatizada y un anodo movil, por medio de una corriente pulsada rectangular.

Energy Technology Data Exchange (ETDEWEB)

Vega G, J D

1994-12-31

In this work, metallic coatings of nickel was made over carbon steel using two different electrolytic solutions: The Watts`s bath and the nickel sulfamate bath, using a pulse variable current. The method use was the traditional method, its means a thermostatic cell and one movable anode, which is a few know technique nowadays, it allow realize depositions away from any laboratory or special workshop, it has the advantage to be a portable dispositive. At last of all the electro depositions the coatings quality was valuable by them physical properties like: adhesion, hardness, wrinkled and thickness. The best results was obtain by the Nickel sulfamate bath and movable anode, less in the thickness, which has higher on the thermostatic cell. The variable current was obtain by a Pulse Generator and a Cathodic galvanometer. (Author).

The dynamical fingerprint of core scouring in massive elliptical galaxies

International Nuclear Information System (INIS)

Thomas, J.; Saglia, R. P.; Bender, R.; Erwin, P.; Fabricius, M.

2014-01-01

The most massive elliptical galaxies have low-density centers or cores that differ dramatically from the high-density centers of less massive ellipticals and bulges of disk galaxies. These cores have been interpreted as the result of mergers of supermassive black hole binaries, which depopulate galaxy centers by gravitationally slingshotting central stars toward large radii. Such binaries naturally form in mergers of luminous galaxies. Here, we analyze the population of central stellar orbits in 11 massive elliptical galaxies that we observed with the integral field spectrograph SINFONI at the European Southern Observatory Very Large Telescope. Our dynamical analysis is orbit-based and includes the effects of a central black hole, the mass distribution of the stars, and a dark matter halo. We show that the use of integral field kinematics and the inclusion of dark matter is important to conclude on the distribution of stellar orbits in galaxy centers. Six of our galaxies are core galaxies. In these six galaxies, but not in the galaxies without cores, we detect a coherent lack of stars on radial orbits in the core region and a uniform excess of radial orbits outside of it: when scaled by the core radius r b , the radial profiles of the classical anisotropy parameter β(r) are nearly identical in core galaxies. Moreover, they quantitatively match the predictions of black hole binary simulations, providing the first convincing dynamical evidence for core scouring in the most massive elliptical galaxies.

Large-region acoustic source mapping using a movable array and sparse covariance fitting.

Science.gov (United States)

Zhao, Shengkui; Tuna, Cagdas; Nguyen, Thi Ngoc Tho; Jones, Douglas L

2017-01-01

Large-region acoustic source mapping is important for city-scale noise monitoring. Approaches using a single-position measurement scheme to scan large regions using small arrays cannot provide clean acoustic source maps, while deploying large arrays spanning the entire region of interest is prohibitively expensive. A multiple-position measurement scheme is applied to scan large regions at multiple spatial positions using a movable array of small size. Based on the multiple-position measurement scheme, a sparse-constrained multiple-position vectorized covariance matrix fitting approach is presented. In the proposed approach, the overall sample covariance matrix of the incoherent virtual array is first estimated using the multiple-position array data and then vectorized using the Khatri-Rao (KR) product. A linear model is then constructed for fitting the vectorized covariance matrix and a sparse-constrained reconstruction algorithm is proposed for recovering source powers from the model. The user parameter settings are discussed. The proposed approach is tested on a 30 m × 40 m region and a 60 m × 40 m region using simulated and measured data. Much cleaner acoustic source maps and lower sound pressure level errors are obtained compared to the beamforming approaches and the previous sparse approach [Zhao, Tuna, Nguyen, and Jones, Proc. IEEE Intl. Conf. on Acoustics, Speech and Signal Processing (ICASSP) (2016)].

Impact of Manually Controlled Solar Shades on Indoor Visual Comfort

Directory of Open Access Journals (Sweden)

Jian Yao

2016-07-01

Full Text Available Daylight plays a significant role in sustainable building design. The purpose of this paper was to investigate the impact of manual solar shades on indoor visual comfort. A developed stochastic model for manual solar shades was modeled in Building Controls Virtual Test Bed, which was coupled with EnergyPlus for co-simulation. Movable solar shades were compared with two unshaded windows. Results show that movable solar shades have more than half of the working hours with a comfortable illuminance level, which is about twice higher than low-e windows, with a less significant daylight illuminance fluctuation. For glare protection, movable solar shades increase comfortable visual conditions by about 20% compared to low-e windows. Moreover, the intolerable glare perception could be reduced by more than 20% for movable solar shades.

Research on the electromagnetic structure of movable coil electromagnet drive mechanism for reactor control rod

International Nuclear Information System (INIS)

Zhang Jige; Yian Huijie; Wu Yuanqiang; Wu Xinxin; Yu Suyuan; He Shuyan

2007-01-01

The movable coil electromagnet drive mechanism (MCEDM) is a new drive scheme for the reactor control rod, and it has a simple structure, good security and reliability property, etc. MCEDM with an air cooled structure has been used in the land research reactor. In order to apply MCEDM to the mobile reactor, experimental and theoretical study on the electromagnet with an oil-water cooled structure and a single magnetic flux circuit (called the type A electro-magnet) has been completed. It is proven by the experiment and theory that the oil-water cooled structure is an excellent measure to increase the coil current of MCEDM. Moreover, a type B electromagnet with an oil-water cooled structure and double magnetic flux circuits is designed to further increase the magnetic force of MCEDM. The analysis of finite element method shows that the type B electromagnet could double the saturation current of type A electro-magnet and the magnetic force of type B electromagnet is greater than that of the type A electromagnet. Moreover, it is proven that the dynamic property of type B electromagnet is better than type A electromagnet. (author)

Characterization of a vertically movable gate field effect transistor using a silicon-on-insulator wafer

Science.gov (United States)

Song, In-Hyouk; Forfang, William B. D.; Cole, Bryan; You, Byoung Hee

2014-10-01

The vertically movable gate field effect transistor (VMGFET) is a FET-based sensing element, whose gate moves in a vertical direction over the channel. A VMGFET gate covers the region between source and drain. A 1 μm thick air layer separates the gate and the substrate of the VMGFET. A novel fabrication process to form a VMGFET using a silicon-on-insulator (SOI) wafer provides minimal internal stress of the gate structure. The enhancement-type n-channel VMGFET is fabricated with the threshold voltage of 2.32 V in steady state. A non-inverting amplifier is designed and integrated on a printable circuit board (PCB) to characterize device sensitivity and mechanical properties. The VMGFET is mechanically coupled to a speaker membrane to apply mechanical vibration. The oscillated drain current of FET are monitored and sampled with NI LabVIEW. The frequency of the output signal correlates with that of the input stimulus. The resonance frequency of the fabricated VMGFET is measured to be 1.11 kHz. The device sensitivity linearly increases by 0.106 mV/g Hz in the range of 150 Hz and 1 kHz.

Characterization of a vertically movable gate field effect transistor using a silicon-on-insulator wafer

International Nuclear Information System (INIS)

Song, In-Hyouk; Forfang, William B D; Cole, Bryan; Hee You, Byoung

2014-01-01

The vertically movable gate field effect transistor (VMGFET) is a FET-based sensing element, whose gate moves in a vertical direction over the channel. A VMGFET gate covers the region between source and drain. A 1 μm thick air layer separates the gate and the substrate of the VMGFET. A novel fabrication process to form a VMGFET using a silicon-on-insulator (SOI) wafer provides minimal internal stress of the gate structure. The enhancement-type n-channel VMGFET is fabricated with the threshold voltage of 2.32 V in steady state. A non-inverting amplifier is designed and integrated on a printable circuit board (PCB) to characterize device sensitivity and mechanical properties. The VMGFET is mechanically coupled to a speaker membrane to apply mechanical vibration. The oscillated drain current of FET are monitored and sampled with NI LabVIEW. The frequency of the output signal correlates with that of the input stimulus. The resonance frequency of the fabricated VMGFET is measured to be 1.11 kHz. The device sensitivity linearly increases by 0.106 mV/g Hz in the range of 150 Hz and 1 kHz. (paper)

Adjustable movable capacitors bank at 20 or 30 MVAr in 115 kV; Banco movil de capacitores ajustable a 20 o 30 MVAr en 115 kV

Energy Technology Data Exchange (ETDEWEB)

Ponce Velez, Marco A; Lopez Velazquez, Juan Jose [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Lopez Tagle, Alfredo; Aragon Garcia, Hector [Comision Federal de Electricidad (Mexico)

1999-07-01

The use of fixed capacitors banks in distribution and transmission systems is a useful tool to compensate the demand of reactive power and the drop of voltage of the power lines. Nevertheless, unforeseen happenings can be originated that could cause decompensation in the system reliability. Due to the previous fact, the Transmission and Transformation Coordinator (CTT) of the Comision Federal de Electricidad (CFE) asked for the design and the construction of a movable bank of capacitors for an emergent compensation of reactive power. In this article it is presented the most relevant of the design, the construction and the operation of the movable bank of capacitors developed in the Instituto de Investigaciones Electricas (IIE). [Spanish] El empleo de bancos capacitadores fijos en los sistemas de distribucion y transmision es una herramienta util para compensar la demanda de reactivos y la caida de tension de las lineas. Sin embargo, se pueden originar imprevistos que descompensan la confiabilidad del sistema. Debido a lo anterior, la Coordinadora de Transmision y Transformacion (CTT) de la Comision Federal de Electricidad (CFE) solicito el diseno y la construccion de un banco movil de capacitores para una compensacion emergente de potencia reactiva. En este articulo se presenta lo mas relevante del diseno, la construccion y la operacion del banco movil de capacitores desarrollado en el Instituto de Investigaciones Electricas (IIE).

The Multipoint Global Shape Optimization of Flying Configuration with Movable Leading Edges Flaps

Directory of Open Access Journals (Sweden)

Adriana NASTASE

2012-12-01

Full Text Available The aerodynamical global optimized (GO shape of flying configuration (FC, at two cruising Mach numbers, can be realized by morphing. Movable leading edge flaps are used for this purpose. The equations of the surfaces of the wing, of the fuselage and of the flaps in stretched position are approximated in form of superpositions of homogeneous polynomes in two variables with free coefficients. These coefficients together with the similarity parameters of the planform of the FC are the free parameters of the global optimization. Two enlarged variational problems with free boundaries occur. The first one consists in the determination of the GO shape of the wing-fuselageFC, with the flaps in retracted position, which must be of minimum drag, at higher cruising Mach number. The second enlarged variational problem consists in the determination of the GO shape of the flaps in stretched position in such a manner that the entire FC shall be of minimum drag at the second lower Mach number. The iterative optimum-optimorum (OO theory of the author is used for the solving of these both enlarged variational problems. The inviscid GO shape of the FC is used only in the first step of iteration and the own developed hybrid solutions for the compressible Navier-Stokes partial-differential equations (PDEs are used for the determination of the friction drag coefficient and up the second step of iteration of OO theory.

Real and virtual explorations of the environment and interactive tracking of movable objects for the blind on the basis of tactile-acoustical maps and 3D environment models.

Science.gov (United States)

Hub, Andreas; Hartter, Tim; Kombrink, Stefan; Ertl, Thomas

2008-01-01

PURPOSE.: This study describes the development of a multi-functional assistant system for the blind which combines localisation, real and virtual navigation within modelled environments and the identification and tracking of fixed and movable objects. The approximate position of buildings is determined with a global positioning sensor (GPS), then the user establishes exact position at a specific landmark, like a door. This location initialises indoor navigation, based on an inertial sensor, a step recognition algorithm and map. Tracking of movable objects is provided by another inertial sensor and a head-mounted stereo camera, combined with 3D environmental models. This study developed an algorithm based on shape and colour to identify objects and used a common face detection algorithm to inform the user of the presence and position of others. The system allows blind people to determine their position with approximately 1 metre accuracy. Virtual exploration of the environment can be accomplished by moving one's finger on a touch screen of a small portable tablet PC. The name of rooms, building features and hazards, modelled objects and their positions are presented acoustically or in Braille. Given adequate environmental models, this system offers blind people the opportunity to navigate independently and safely, even within unknown environments. Additionally, the system facilitates education and rehabilitation by providing, in several languages, object names, features and relative positions.

Theoretical and experimental analysis of a linear accelerator endowed with single feed coupler with movable short-circuit.

Science.gov (United States)

Dal Forno, Massimo; Craievich, Paolo; Penco, Giuseppe; Vescovo, Roberto

2013-11-01

The front-end injection systems of the FERMI@Elettra linac produce high brightness electron beams that define the performance of the Free Electron Laser. The photoinjector mainly consists of the radiofrequency (rf) gun and of two S-band rf structures which accelerate the beam. Accelerating structures endowed with a single feed coupler cause deflection and degradation of the electron beam properties, due to the asymmetry of the electromagnetic field. In this paper, a new type of single feed structure with movable short-circuit is proposed. It has the advantage of having only one waveguide input, but we propose a novel design where the dipolar component is reduced. Moreover, the racetrack geometry allows to reduce the quadrupolar component. This paper presents the microwave design and the analysis of the particle motion inside the linac. A prototype has been machined at the Elettra facility to verify the new coupler design and the rf field has been measured by adopting the bead-pull method. The results are here presented, showing good agreement with the expectations.

Theoretical and experimental analysis of a linear accelerator endowed with single feed coupler with movable short-circuit

International Nuclear Information System (INIS)

Forno, Massimo Dal; Craievich, Paolo; Penco, Giuseppe; Vescovo, Roberto

2013-01-01

The front-end injection systems of the FERMI@Elettra linac produce high brightness electron beams that define the performance of the Free Electron Laser. The photoinjector mainly consists of the radiofrequency (rf) gun and of two S-band rf structures which accelerate the beam. Accelerating structures endowed with a single feed coupler cause deflection and degradation of the electron beam properties, due to the asymmetry of the electromagnetic field. In this paper, a new type of single feed structure with movable short-circuit is proposed. It has the advantage of having only one waveguide input, but we propose a novel design where the dipolar component is reduced. Moreover, the racetrack geometry allows to reduce the quadrupolar component. This paper presents the microwave design and the analysis of the particle motion inside the linac. A prototype has been machined at the Elettra facility to verify the new coupler design and the rf field has been measured by adopting the bead-pull method. The results are here presented, showing good agreement with the expectations

Movable detector to search for neutrino oscillations in the BNL neutrino beam

International Nuclear Information System (INIS)

Bozoki, G.; Fainberg, A.; Weygand, D.; Fagg, L.; Uberall, H.; Goldberg, M.; Meadows, B.; Saenz, A.W.; Seeman, N.

1980-01-01

A simple, straightforward, and economic experiment utilizing a set of water Cherenkov counters is proposed to search for neutrino oscillations in the AGS neutrino beam. The detector will be movable and will be able to provide reasonable counting rates up to 2 km downstream of the pion decay tunnel. Whereas previous accelerator experiments have sought to increase the ratio l/p (with l the neutrino path length and p its momentum) by decreasing p, increasing l is suggested instead. Further, by making measurements at several different values of l with the same apparatus, many sources of systematic error are eliminated. The experiment will measure beam-associated muon- and electron-type events at each position. A change in the ratio of muon- to electron-type events as a function of position would be evidence for ν/sub μ/ + ν/sub e/ oscillations. Sensitivity in terms of (Δm) 2 (the square of the mass difference in the mass eigenstates) can be as low as 0.1 eV 2 , for full mixing, which is below the most probable value found by Reines et al for Δm 2 in their electron neutrino reactor experiment. This experiment would be parasitic, running behind the usual neutrino beam experiments, assuming the nominal beam energy (peaked at 1 GeV), and would thus make a minimal demand on AGS support. It is suggested that the first two measurements be made inside the Isabelle tunnel at the points of intersection with the AGS neutrino beam. No further excavations would be required, and the data could be taken before ISA equipment is installed

Artificial Reef Effect in relation to Offshore Renewable Energy Conversion: State of the Art

Directory of Open Access Journals (Sweden)

Olivia Langhamer

2012-01-01

Full Text Available The rapid worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization, thus acting as artificial reefs. The artificial reef effect is important when constructing, for example, scour protections since it can generate an enhanced habitat. Specifically, artificial structures can create increased heterogeneity in the area important for species diversity and density. Offshore energy installations also have the positive side effect as they are a sanctuary area for trawled organisms. Higher survival of fish and bigger fish is an expected outcome that can contribute to a spillover to outer areas. One negative side effect is that invasive species can find new habitats in artificial reefs and thus influence the native habitats and their associated environment negatively. Different scour protections in offshore wind farms can create new habitats compensating for habitat loss by offshore energy installations. These created habitats differ from the lost habitat in species composition substantially. A positive reef effect is dependent on the nature and the location of the reef and the characteristics of the native populations. An increase in surface area of scour protections by using specially designed material can also support the reef effect and its productivity.

Radiation protection in occupational exposure to microwave electrotherapy units

International Nuclear Information System (INIS)

Guardia, V.; Ferrer, S.; Alonso, O.; Almonacid, M.

2012-01-01

During the last years, electromagnetic emitters are more and more commonly used for therapeutic treatments in electrotherapy centers. This extended use has caused worries workers, who believe that microwave radiation radiation might have effects similar to those induced by radioactivity, even if the only effects recognised by international regulatory bodies concerning microwave exposure of humans are those of thermal origin. The present study aims to answer the existing concerns about electromagnetic exposure in electrotherapy facilities. After monitoring environmental values in an electrotherapy facility, we conclude that actions must be undertaken in order to reduce the exposure levels, as proposed by the current European guidelines, which should become legally binding for all EU state members within the current year. With the purpose of reducing potential risks of occupational overexposure, we are developing innovative fabrics for microwave shielding. These new materials are able to attenuate 85% of the microwave radiation. As these are light materials, they can be used in all kind of facilities, as wall covers, movable screens or even as personal protection, like lab clothes or gloves. (Author) 6 refs.

Design and construction of the movable limiters for holding the plasma in position in the nuclear fusion experiment TEXTOR

International Nuclear Information System (INIS)

Butzek, D.A.; Derichs, K.

1983-11-01

The nuclear fusion experiment TEXTOR (Tokamak Experiment for Technology Oriented Research) has been constructed for investigation of plasma-wall-interaction. The plasma is generated inside a torus-shaped vacuum vessel. In addition to the magnetic fields mechanical limiters are provided to hold the plasma in position. The limiter scheme of textor consists of main limiters and reference limiters (measuring limiters). Main and reference limiters are mounted in different cross sections of the torus. The main limiters are movable during the plasma discharge while the reference limiters are kept fixed. They are adjustable. Thus, by moving the main limiters, the reference limiters can be exposed to different thermal loads during the discharge. Exposing the reference limiters to the plasma, first results have been obtained concerning the scrape off layer: thickness, fluxes of hydrogen and chromium through this layer. The limiter scheme, the final design and construction of the limiters and the first phase of operation are described in this report. (orig.) [de

Modelling multi-phase liquid-sediment scour and resuspension induced by rapid flows using Smoothed Particle Hydrodynamics (SPH) accelerated with a Graphics Processing Unit (GPU)

Science.gov (United States)

Fourtakas, G.; Rogers, B. D.

2016-06-01

A two-phase numerical model using Smoothed Particle Hydrodynamics (SPH) is applied to two-phase liquid-sediments flows. The absence of a mesh in SPH is ideal for interfacial and highly non-linear flows with changing fragmentation of the interface, mixing and resuspension. The rheology of sediment induced under rapid flows undergoes several states which are only partially described by previous research in SPH. This paper attempts to bridge the gap between the geotechnics, non-Newtonian and Newtonian flows by proposing a model that combines the yielding, shear and suspension layer which are needed to predict accurately the global erosion phenomena, from a hydrodynamics prospective. The numerical SPH scheme is based on the explicit treatment of both phases using Newtonian and the non-Newtonian Bingham-type Herschel-Bulkley-Papanastasiou constitutive model. This is supplemented by the Drucker-Prager yield criterion to predict the onset of yielding of the sediment surface and a concentration suspension model. The multi-phase model has been compared with experimental and 2-D reference numerical models for scour following a dry-bed dam break yielding satisfactory results and improvements over well-known SPH multi-phase models. With 3-D simulations requiring a large number of particles, the code is accelerated with a graphics processing unit (GPU) in the open-source DualSPHysics code. The implementation and optimisation of the code achieved a speed up of x58 over an optimised single thread serial code. A 3-D dam break over a non-cohesive erodible bed simulation with over 4 million particles yields close agreement with experimental scour and water surface profiles.

System of diagnosis of generators computer aided integrated into a movable laboratory; Sistema de diagnostico de generadores asistido por computadora integrado a un laboratorio movil

Energy Technology Data Exchange (ETDEWEB)

De la Torre Vega, H. Octavio; Escorsa Morales, Oscar; Castaneda Parra, Adelina; Garcia- Colon H, Rodolfo [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Lopez Azamar, Ernesto [Comision Federal de Electricidad (Mexico)

1999-07-01

The development of the Movable Laboratory is presented, which will allow to combine and document the knowledge acquired by more than ten years of experience in diagnosis of electrical generators. The development of the project is divided into three main parts: laboratory design, data acquisition system (Datec) and system of diagnosis of generators computer aided (Cadis). [Spanish] Se presenta el desarrollo del Laboratorio Movil, el cual permitira conjuntar y documentar el conocimiento adquirido por mas de diez anos de experiencia en diagnostico de generadores electricos. El desarrollo del proyecto se divide en tres grandes partes: diseno de laboratorio, sistema de adquisicion de datos (Datec) y sistema de diagnostico de generadores asistido por computadora (Cadis).

Development of a formalism of movable cellular automaton method for numerical modeling of fracture of heterogeneous elastic-plastic materials

Directory of Open Access Journals (Sweden)

S. Psakhie

2013-04-01

Full Text Available A general approach to realization of models of elasticity, plasticity and fracture of heterogeneous materials within the framework of particle-based numerical methods is proposed in the paper. It is based on building many-body forces of particle interaction, which provide response of particle ensemble correctly conforming to the response (including elastic-plastic behavior and fracture of simulated solids. Implementation of proposed approach within particle-based methods is demonstrated by the example of the movable cellular automaton (MCA method, which integrates the possibilities of particle-based discrete element method (DEM and cellular automaton methods. Emergent advantages of the developed approach to formulation of many-body interaction are discussed. Main of them are its applicability to various realizations of the concept of discrete elements and a possibility to realize various rheological models (including elastic-plastic or visco-elastic-plastic and models of fracture to study deformation and fracture of solid-phase materials and media. Capabilities of particle-based modeling of heterogeneous solids are demonstrated by the problem of simulation of deformation and fracture of particle-reinforced metal-ceramic composites.

Influence of argon/oxygen atmospheric dielectric barrier discharge treatment on desizing and scouring of poly (vinyl alcohol) on cotton fabrics

International Nuclear Information System (INIS)

Peng Shujing; Gao Zhiqiang; Sun Jie; Yao Lan; Qiu Yiping

2009-01-01

The effect of argon/oxygen atmospheric dielectric barrier discharge (DBD) treatment on desizing and scouring of polyvinyl alcohol (PVA) on cotton fabric was studied with respect to the treatment duration of 1, 2, 4 and 6 min. X-ray photoelectron spectroscopy (XPS) analysis indicated that oxygen concentration increased for the plasma treated PVA film. Solubility measurement revealed that plasma treatment increased PVA solubility in hot washing but less effective in cold washing. Scanning electron microscopy (SEM) showed that the fiber surfaces were as clean as unsized fibers after 6 min treatment followed by hot washing. Wickability analysis indicated that the capillary heights of plasma treated fabrics increased significantly as the plasma treatment duration increased. The results of the yarn tensile strength test showed that the plasma treatment did not have a negative effect on fabric tensile strength.

Infauna monitoring Horns Rev offshore wind farm. Annual state report 2004

Energy Technology Data Exchange (ETDEWEB)

Bech, M.; Frederiksen, R.; Pedersen, John; Leonhard, S.B.

2005-04-15

A total of 40 species were identified from the surveys in the Horns Rev area in September 2004 while 42 species were identified in 2003 and 47 species in September 2001. The decline in the number of species occurred both inside the wind farm and reference areas, which indicates that the decline could be a combination of changes in sediment characteristics and natural variation rather than an effect from the establishment of the wind farm. More species were not associated with the hard substrate at the turbine sites in 2004 compared to 2003, while in 2001, more species were associated with fine-grained sand. The median sediment grain size increased from 2001 to 2003 to 2004, which suggests that the velocity of the current increased, but modelling calculations on current speed predicted a 2% reduction in the wind farm area and up to a 15% reduction very close to the scour protection. These results agreed with the grain sizes found at the stations 5, 25 and 100 metres from the scour protection. At most stations, the medium grain size was 5 metres lower from the scour protection compared with the station 100 metres from the scour protection, which indicates that the velocity of the current was lower close to the scour protection. No significant impact on the infauna in the wind farm area was detectable concerning distance-related effects. Though general reductions in the population size of some of the character species in the surveyed areas might be related to changes in the sediment structure, the infauna community at Horns Rev showed no obvious sign of stress response as a consequence of possible impact from construction and operating activities. New species were observed in 2003 and 2004 and some of these might be a result of sediment characteristics, less predation or natural variation. The recording of other species might be a result of the introduction of hard bottom habitants in the wind farm area. The density of the most abundant bivalves and bristle worms was

Infauna monitoring Horns Rev offshore wind farm. Annual status report 2004

International Nuclear Information System (INIS)

Bech, M.; Frederiksen, R.; Pedersen, John; Leonhard, S.B.

2005-04-01

A total of 40 species were identified from the surveys in the Horns Rev area in September 2004 while 42 species were identified in 2003 and 47 species in September 2001. The decline in the number of species occurred both inside the wind farm and reference areas, which indicates that the decline could be a combination of changes in sediment characteristics and natural variation rather than an effect from the establishment of the wind farm. More species were not associated with the hard substrate at the turbine sites in 2004 compared to 2003, while in 2001, more species were associated with fine-grained sand. The median sediment grain size increased from 2001 to 2003 to 2004, which suggests that the velocity of the current increased, but modelling calculations on current speed predicted a 2% reduction in the wind farm area and up to a 15% reduction very close to the scour protection. These results agreed with the grain sizes found at the stations 5, 25 and 100 metres from the scour protection. At most stations, the medium grain size was 5 metres lower from the scour protection compared with the station 100 metres from the scour protection, which indicates that the velocity of the current was lower close to the scour protection. No significant impact on the infauna in the wind farm area was detectable concerning distance-related effects. Though general reductions in the population size of some of the character species in the surveyed areas might be related to changes in the sediment structure, the infauna community at Horns Rev showed no obvious sign of stress response as a consequence of possible impact from construction and operating activities. New species were observed in 2003 and 2004 and some of these might be a result of sediment characteristics, less predation or natural variation. The recording of other species might be a result of the introduction of hard bottom habitants in the wind farm area. The density of the most abundant bivalves and bristle worms was

A simple method to achieve full-field and real-scale reconstruction using a movable stereo rig

Science.gov (United States)

Gu, Feifei; Zhao, Hong; Song, Zhan; Tang, Suming

2018-06-01

This paper introduces a simple method to achieve full-field and real-scale reconstruction using a movable binocular vision system (MBVS). The MBVS is composed of two cameras, one is called the tracking camera, and the other is called the working camera. The tracking camera is used for tracking the positions of the MBVS and the working camera is used for the 3D reconstruction task. The MBVS has several advantages compared with a single moving camera or multi-camera networks. Firstly, the MBVS could recover the real-scale-depth-information from the captured image sequences without using auxiliary objects whose geometry or motion should be precisely known. Secondly, the removability of the system could guarantee appropriate baselines to supply more robust point correspondences. Additionally, using one camera could avoid the drawback which exists in multi-camera networks, that the variability of a cameras’ parameters and performance could significantly affect the accuracy and robustness of the feature extraction and stereo matching methods. The proposed framework consists of local reconstruction and initial pose estimation of the MBVS based on transferable features, followed by overall optimization and accurate integration of multi-view 3D reconstruction data. The whole process requires no information other than the input images. The framework has been verified with real data, and very good results have been obtained.

Plasma facing components design of KT-2 tokamak

International Nuclear Information System (INIS)

In, Sang Ryul; Yoon, Byung Joo; Song, Woo Soeb; Xu, Chao Yin

1997-04-01

The vacuum vessel of KT-2 tokamak is protected from high thermal loads by various kinds of plasma facing components (PFC): outer and inner divertors, neutral baffle, inboard limiter, poloidal limiter, movable limiter and passive plate, installed on the inner wall of the vessel. In this report the pre-engineering design of the plasma facing components, including design requirements and function, structures of PFC assemblies, configuration of cooling systems, calculations of some mechanical and hydraulic parameters, is presented. Pumping systems for the movable limiter and the divertor are also discussed briefly. (author). 49 figs

Preventing erosion at pipeline crossings of watercourses

International Nuclear Information System (INIS)

Sawatsky, L.; Arnold, G.

1997-01-01

Watercourses are naturally vulnerable to erosion but the risk is particularly acute after sub-soil and armour materials have been disturbed by trenching and backfilling during construction. Various types of erosion (river scour, river bed, river channel bed and river bank ) and the progressive removal of pipeline cover resulting from erosion were discussed. Methods of estimating the risk of progressive erosion, river avulsions and beaver dam scour, and methods of mitigating erosion at pipeline crossings such as deep burial, proper siting, conventional armouring, and a combination of bank toe protection, and upper bank vegetation cover, were described

Electrochemical decontamination of metallic surfaces by means of a movable electrode

International Nuclear Information System (INIS)

Mihai, F.; Nicu, M.; Cazan, L.; Turcanu, C.

1998-01-01

Electrochemical decontamination can be considered to be a decontamination assisted by an electrochemical field. The method is applied to the metallic surface decontamination for contaminants of any physico-chemical nature. The physico-chemical phenomenon that is the basis for the electrochemical methods is the anodic layer dissolution. By dissolution of the superficial layer any radioactive contaminant on the surface or entrapped within the surface oxide is eliminated. Electrochemical decontamination, also known as electropolishing, involves the use of the object to be cleaned as an anode in an electrochemical cell. The passage of current results in anodic dissolution of the surface material. Generally, there are many methods of application for electropolishing. The most common method is immersing the object to be decontaminated in a tank filled with a suitable electrolyte. The electrochemical method with movable electrode involves the use of 'in situ' mobile devices that are able to electropolish punctual surfaces in places difficult to access. The advantages are the simplicity of the setup, short times of application and reduced waste volumes. Phosphoric and sulphuric acid mixture is used as the electrolyte in electropolishing because of its stability, safety and applicability to a variety of alloy systems. The method was applied to decontaminate carbon steel, aluminium and copper. Used contaminants are mixtures of 60 Co and 134 Cs; 60 Co and 65 Zn; 60 Co, 65 Zn and 134 Cs. After preparation, the samples were kept in laboratory conditions about one month, to simulate real conditions and to let the chemical reactions between contaminant and sample material constitution to complete. To calculate decontamination factor characteristic for each studied decontamination method the following radiometric measurements are necessary: - activity measurement after radioisotope solution contamination representing initial activity Λ in ; - activity measurement after

Offshore wind energy developments

DEFF Research Database (Denmark)

Stolpe, Mathias; Buhl, Thomas; Sumer, B. Mutlu

2014-01-01

This chapter will give a brief overview of a few of the activities within offshore wind energy research, specifically 1) Support structure optimization, 2) Blade coatings for wind turbines; 3) Scour protection of foundations, 4) Offshore HVDC and 5) Offshore wind services....

Clinical Effect of Acute Complete Acromioclavicular Joint Dislocation Treated with Micro-Movable and Anatomical Acromioclavicular Plate

Science.gov (United States)

Liu, Qingjun; Miao, Jianyun; Lin, Bin; Guo, Zhimin

2012-01-01

Objectives: We evaluated the long-term clinical results of acute complete acromioclavicular dislocations treated with micro-movable and anatomical acromioclavicular plate. Methods: Open reduction and internal fixation was performed using the MAAP in 16 patients (10 males, 6 females; mean age 36 years; range16 to 63 years) with acute complete acromioclavicular joint dislocation. Radiographic evaluations were routinely conducted every 3 weeks until 3 months postoperatively. The MAAP were removed under local anesthesia after 3 months postoperatively. We evaluated the functional results by using the constant scoring system and radiological results in the last follow-up time. The mean follow up was 26 months (range 16 to 38 months). Results: The mean Constant score was 94 (range, 78 to 100). The results were excellent in 12 patients (75.0%), good in 3 patients (18.8%) and satisfactory in 1patient (6.2%). Three patients with scores of 80 to 90 had mild pain during activity, but have not affected the shoulder range of motion. One patient has both some pain and limited range of motion of shoulder joint. All patients but one have returned to their preoperative work without any limitations. Compared to the contralateral side, radiography showed anatomical reposition in the vertical plane in 14 cases, slight loss of reduction in 2 older patients. Conclusion: We recommend the MAAP fixation for surgical treatment of acute complete acromioclavicular joint dislocation as it could provide satisfactory shoulder functions and clinical results, with lower complication rate. However, it is necessary to continue to observe the clinical effects of this fixation technique. PMID:23091410

Physical modeling of river spanning rock structures: Evaluating interstitial flow, local hydraulics, downstream scour development, and structure stability

Science.gov (United States)

Collins, K.L.; Thornton, C.I.; Mefford, B.; Holmquist-Johnson, C. L.

2009-01-01

Rock weir and ramp structures uniquely serve a necessary role in river management: to meet water deliveries in an ecologically sound manner. Uses include functioning as low head diversion dams, permitting fish passage, creating habitat diversity, and stabilizing stream banks and profiles. Existing information on design and performance of in-stream rock structures does not provide the guidance necessary to implement repeatable and sustainable construction and retrofit techniques. As widespread use of rock structures increases, the need for reliable design methods with a broad range of applicability at individual sites grows as well. Rigorous laboratory testing programs were implemented at the U.S. Bureau of Reclamation (Reclamation) and at Colorado State University (CSU) as part of a multifaceted research project focused on expanding the current knowledge base and developing design methods to improve the success rate of river spanning rock structures in meeting project goals. Physical modeling at Reclamation is being used to measure, predict, and reduce interstitial flow through rock ramps. CSU is using physical testing to quantify and predict scour development downstream of rock weirs and its impact on the stability of rock structures. ?? 2009 ASCE.

Small-sized linear accelerator of 2.5 MeV electrons with a local radiation shield for custom examination of freight transported by motor transport

International Nuclear Information System (INIS)

Baklanov, A.V.; Gavrish, Yu.N.; Klinov, A.P.; Krest'yaninov, A.S.; Nikolaev, V.M.; Fomin, L.P.; Linkenbach, H.A.; Geus, G.; Knospel, W.

2001-01-01

A new development of a small-sized linear accelerator of 2.5 MeV electrons with a local radiation protection is described. The accelerator is intended for movable facilities of radiation custom of the freight transported by motor transport. Main constructive solutions, mass and dimension characteristics and results of preliminary tests of the accelerator parameters and characteristics of radiation protection are presented [ru

Crash energy management on the base of Movable cellular automata method

Science.gov (United States)

Psakhie, Serguei; Dmitriev, Andrei; Shilko, Evgueni; Tatarintsev, Evgueni; Korostelev, Serguei

2001-06-01

One of the main problems of materials science is increasing of structure's viability under dynamic loading. In general, a solution is the management of transformation of the energy of loading to the energy of destroying of the least important parts and details of the structure. It has to be noted that similar problem also exists in materials science, since a majority of modern materials are heterogeneous and have a complex internal structure. To optimize this structure for working under dynamic loading it is necessary to take into account the redistribution of elastic energy including phase transformation, generation and accumulation of micro-damages, etc. As far as real experiments on destroying the complex objects are sufficiently expensive and getting of detailed information is often associates with essential difficulties, the methods of computer modeling are used in solving the similar problems. As a rule, these are the methods of continuum mechanics. Although essential achievements have been obtained on the basis of these methods the continuum approach has several limitations, connected first of all with the possibility of description of generation of damages, formation and development of cracks and mass mixing effects. These problems may be solved on the basis of the Movable Cellular Automata (MCA) method, which has been successfully used for modeling fracture of the different material and structures In the paper behavior and peculiarities of failure of complex structures and materials under dynamic loading are studied on the basis of computer modeling. The results shown that sometimes even small changes of the internal structure leads to the significant increasing of the viability of the complex structures and materials. It is due to the elastic energy flux change over during the dynamical loading. This effect may be explained by the fact that elastic energy fluxes define the current stress concentration. Namely, because the area of inclusions are subjected

Half-Space Temperature Field with a Movable Thermally Thin-Coated Boundary Under External Heat Flux

Directory of Open Access Journals (Sweden)

P. A. Vlasov

2014-01-01

Full Text Available In engineering practice analytical methods of the mathematical theory of heat conduction hold a special place. This is due to many reasons, in particular, because of the fact that the solutions of the relevant problems represented in analytically closed form, can be used not only for a parametric analysis of the studied temperature field and to explore the specific features of its formation, but also to test the developed computational algorithms, which are aimed at solving real-world application heat and mass transfer problems. Difficulties arising when using the analytical mathematical theory methods of heat conduction in practice are well known. Also they are significantly exacerbated if the boundaries of the system under study are movable, even in the simplest case, when the law of motion is known.The main goal of the conducted research is to have an analytically closed-form problem solution for finding the orthotropic half-space temperature field, a boundary of which has thermally thin coating exposed to extremely concentrated stationary external heat flux and uniformly moves parallel to itself.The assumption that the covering of the boundary is thermally thin, allowed to realize the idea of \\concentrated capacity", that is to accept the hypothesis that the mean-thickness coating temperature is equal to the temperature of its boundaries. This assumption allowed us to reduce the problem under consideration to a mixed problem for a parabolic equation with a specific boundary condition.The Hankel integral transform of zero order with respect to the radial variable and the Laplace transform with respect to the temporal variable were used to solve the reduced problem. These techniques have allowed us to submit the required solution as an iterated integral.

Mechanical design control and implementation of a new movable diagnostic probe for the TRIUMF cyclotron

International Nuclear Information System (INIS)

Ries, T.C.

1993-11-01

A new movable probe has been installed into the TRIUMF H - cyclotron. It is intended to measure the distribution of betatron amplitudes, in the vertical plane, of the circulating beam and to scrape halo. The probe, however, may also be scanned in the radial direction. The head may be positioned vertically and horizontally to an accuracy of .002 in. The device is mechanically modular to facilitate fast and easy handling for maintenance in a radioactive area. The beam sensor on the probe head is a 1.25 in. x 3 in. x 0.003 in. tantalum foil and its overall coverage is 3.00 in. X 7.25 in. in a vertical plane orthogonal to, and crossing through the beam orbit plane. Presently its radial centre line location corresponds to a proton beam energy of about 430 MeV at radius 296 in., however, the probe device may be easily relocated to operate from any 4 in. port, and, with an adaptor port flange, may be installed into any port in the cyclotron vacuum tank. A stationary catcher below the probe path collects those electrons stripped from the H - beam and scattered out from the probe head. The probe axis is vertical and the tank aperture is narrow so a worm gear arrangement combined with a modified 'Evans' - parallel linkage mechanism is used to transform vertical rotary motion into horizontal linear motion. The actuators are dc servo motors with tachometers driven by pulse width modulated servo amplifiers. Position sensing is done by variable reluctance type absolute rotary encoders and the higher level positioning is performed by TRIMAC based control software. The precision of movement and jitter was measured in the laboratory. Examples will be given of the probe use with beam. (author). 5 refs., 3 figs

A study on temperature effects on hydrogen recycling and molybdenum impurity emission from a movable limiter in TRIAM-1M Tokamak

International Nuclear Information System (INIS)

Bhattacharyay, R.; Zushi, H.; Nakashima, K.; Shikama, T.; Sakamoto, M.; Yoshida, N.; Kado, S.; Sawada, K.; Hirooka, Y.; Nakamura, K.; Hanada, K.; Idei, H.; Hasegawa, M.; Sato, K.N.; Ogawa, M.; Takaki, O.; Sasaki, K.; Xu, H.; Kawasaki, S.; Nakashima, H.; Higashijima, A.

2007-01-01

In order to investigate the surface temperature effects on plasma fuel recycling and impurity release from the plasma facing components, plasma discharges have been performed under selected plasma-wall interaction (PWI) conditions in the high-field superconducting tokamak, TRIAM-1M. By moving a water-cooled molybdenum movable limiter (ML) beyond the last closed flux surface, as defined by poloidal limiters, the surface temperature profile on it is varied. Hot spots have been observed on the ML surface in such conditions. The release behaviour of fuel as well as impurity particles from the ML surface has been studied as a function of hot spot temperature (T hot ) by means of wide range spectroscopy (200-1600 nm). A critical T hot is found to be ∼2100 K above which the emission of both hydrogen and impurity particles enhances significantly. This is indicative of some thermally activated process playing an important role in PWIs between the limiter and the edge plasma. With the rise in hot spot temperature localized PWI at the ML is found to dominate the global recycling even when external fuelling is stopped

Analysis of Wave Reflection from Wave Energy Converters Installed as Breakwaters in Harbour

DEFF Research Database (Denmark)

Zanuttigh, B.; Margheritini, Lucia; Gambles, L.

2009-01-01

loads on the structure, i.e. better survivability. Nevertheless these devices must comply with the requirements of harbour protection structures and thus cope with problems due to reflection of incoming waves, i.e. dangerous sea states close to harbors entrances and intensified sediment scour, which can...

Interface stability of granular filter structures under currents

NARCIS (Netherlands)

Verheij, H.J.; Hoffmans, G.; Dorst, K.; Van de Sande, S.

2012-01-01

Granular filters are used for protection of structures against scour and erosion. For a proper functioning it is necessary that the interfaces between the filter structure, the subsoil and the water flowing above the filter structure are stable. Stability means that there is no transport of subsoil

Finite Difference Schemes as Algebraic Correspondences between Layers

Science.gov (United States)

Malykh, Mikhail; Sevastianov, Leonid

2018-02-01

For some differential equations, especially for Riccati equation, new finite difference schemes are suggested. These schemes define protective correspondences between the layers. Calculation using these schemes can be extended to the area beyond movable singularities of exact solution without any error accumulation.

The movable digital planetary from the Cruzeiro do Sul University as a distributing agent of astronomy

Science.gov (United States)

Voelzke, Marcos Rincon

2012-10-01

The Movable Digital Planetary from the Cruzeiro do Sul University has been working in order to publicize and to popularize Astronomy, in particular among students and teachers of Primary (EF) and Medium (EM) Education in municipal and state schools of the City of São Paulo, but also for the general public at large. The aim of this paper is to show and publicize the activities already undertaken by this planetary. In 2010, several presentations were recorded, such as: for the School Cruzeiro do Sul, in São Miguel Paulista, serving 161 children in the EF; Eighth Symposium on Education, Cruzeiro do Sul University, 75 students; NGO Educational Project Capuano, Anália Franco, 30 adults: Fair Student Guide in Shopping Center Norte, 455 people; NGO Association for Charitable Paulista, Burgo Paulista, 70 children; Workshop of Advanced Computing and Informatics, Cruzeiro do Sul University, 37 students; Day of Social Responsibility, Social Work in Don Bosco, Itaquera, 133 people! . In 2011 the presentations took place during the XIII Regional Meeting of Astronomy Education at Cruzeiro do Sul University, serving 112 teachers; College Cruzeiro do Sul, São Miguel Paulista, 356 children of the EF; College Brasilia from São Paulo, Anália Franco, 102 children in the EF and for the Scout Group Caramuru, São Paulo, 104 children. The applied methodology in all presentations consisted of the exhibition of two videos about Astronomy with a subsequent discussion about the presented issues. Previous surveys have shown a great interest in the majority of participants in wanting to learn more about the subject, which clearly explains the importance of education in non-formal places for the teaching of Astronomy

Successive Transfers Relating to Movable Tangible Assets and Acquisition of Property under Article 937, Paragraph (1 of the Civil Code

Directory of Open Access Journals (Sweden)

Mara Ioan

2015-12-01

Full Text Available Apparently article 1275, paragraph (1 of the Civil Code covers all situations that may arise in practice, without making a distinction for the constituent or transferring contracts if they are of the same or of different nature. However, we appreciate that article 1275 of the Civil Code does not apply in all situations of successive transfers relating to movable tangible property granted by the same legal subject. Corroborating this text with the norms in article 937 paragraph (1 of the Civil Code and article1273 paragraph (1 of the Civil Code it leads to the solution according to which article 1275 of the Civil Code regards only the cases where the transfer of successive property are of the same nature, the onerous primary act has not resulted in immediate transmission of real previous right of the document with the free subsidiary title and when the primal act is free, and the alternative is onerous. It is excluded, thus from the application of the rule in question when the primary onerous act had as effect the immediate transmission of the real right and then, but without having occurred the delivery of the asset by the acquirer, it was concluded a document with a free title, subsidiary.

Umbilical mechanism

Science.gov (United States)

Barron, Daniel R. (Inventor); Jasulaitis, Vytas (Inventor); Morrill, Brion F. (Inventor)

1995-01-01

Apparatus is described for automatically mating a pair of connectors and protecting them prior to mating, which minimizes weight and uses relatively simple and reliable mechanisms. Lower and upper connectors (24, 26) are held in lower and upper parts (14, 16) of a housing, with the upper connector mounted on a carrier (32) that is motor driven to move down and mate the connectors. A pair of movable members (36, 38) serve as shields, as coarse alignment aids, and as force transmitters. The movable members are pivotally mounted at the bottom of the upper housing, and as the carrier moves down it pivots the members out of the way. The movable members have socket elements (116) that closely receive pin elements (120) on the lower housing part, to coarsely align the connectors and to react mating and unmating forces between the housings. The carrier has a pair of plate portions (60, 62) with slots (64), and the movable members have cam followers engaged with the slot walls, to move the members with precision. The carrier plate-like portions engage follower members (82) that pivot open lower shield parts (44, 46) covering the lower connector, which is mounted on four stacks of Belleville washers (142).

Sinking of armour layer around a vertical cylinder exposed to waves and current

DEFF Research Database (Denmark)

Nielsen, Anders Wedel; Probst, Thomas; Petersen, Thor Ugelvig

2015-01-01

The mechanisms of the sinking of a scour protection adjacent to a monopile are described in this paper, together with the determination of the equilibrium sinking depth in various wave and combined wave and current conditions based on physical model tests.Sinking of the rocks may ultimately lead ...

Nuclear Reactor RA Safety Report, Vol. 9, Radiation protection; Izvestaj o sigurnosti nuklearnog reaktora RA, Knjiga 9, Zastita od zracenja

Energy Technology Data Exchange (ETDEWEB)

NONE

1986-11-01

Instrumentation for Radiation protection existing at the RA reactor is dating mostly from the period 1957-1959 when the reactor has been built. With some minor exception it was produced in USSR. Radiation protection system was constructed based on specific design project, somewhat modified original USSR project which has been indispensable because of some modification of the building design. During the past 27 years no renewal of the instrumentation was done, only maintenance was performed. Instrumentation consists of old electronic devices which caused difficulties and even prevented regular maintenance because of lack of spare parts. Instrumentation for radiation protection at the RA reactor is classified as follows: centralized dosimetry system; stationary dosimetry instrumentation, movable and personal dosimetry systems. Apart from the scheme of dosimetry instrumentation this volume includes description of radiation protection procedures; protection devices; radiation doses and dose limit data; program for environmental radioactivity control; medical control procedures. [Serbo-Croat] Instrumentacija za zastitu od zracenja koja danas postoji na reaktoru RA najvecim delom potice iz perioda 1957-1959 kada je reaktor gradjen. Sa malim izuzetcima instrumentacija je proizvedena u SSSR. Sistem za zastitu izveden je na osnovu posebnog projekta koji predstavlja modifikaciju originalnog projekta koja je bila neophodna usled modifikovanog gradjevinskog projekta. U proteklom periodu od 27 godina instrumentacija nije obnavljana vec je vrseno samo odrzavanje. Instrumentacija je izradjena u danas prevazidjenoh tehnoligiji (elektronske cevi) sto je otezavalo i skoro onemogucavalo normalno odrzavanje. Instrumentacija za zastitu od zracenja na reaktoru RA moze se podeliti na tri dela: centralizovani dozimetrijski sistem; stacionarna dozimetrijska instrumentacija; prenosna i licna dozimetrijska instrumentacija. Pored seme sistema dozimetrijske kontrole ova knjiga sadrzi opis

Monitoring of levees, bridges, pipelines, and other critical infrastructure during the 2011 flooding in the Mississippi River Basin: Chapter J in 2011 floods of the central United States

Science.gov (United States)

Densmore, Brenda K.; Burton, Bethany L.; Dietsch, Benjamin J.; Cannia, James C.; Huizinga, Richard J.

2014-01-01

During the 2011 Mississippi River Basin flood, the U.S. Geological Survey evaluated aspects of critical river infrastructure at the request of and in support of local, State, and Federal Agencies. Geotechnical and hydrographic data collected by the U.S. Geological Survey at numerous locations were able to provide needed information about 2011 flood effects to those managing the critical infrastructure. These data were collected and processed in a short time frame to provide managers the ability to make a timely evaluation of the safety of the infrastructure and, when needed, to take action to secure and protect critical infrastructure. Critical infrastructure surveyed by the U.S. Geological Survey included levees, bridges, pipeline crossings, power plant intakes and outlets, and an electrical transmission tower. Capacitively coupled resistivity data collected along the flood-protection levees surrounding the Omaha Public Power District Nebraska City power plant (Missouri River Levee Unit R573), mapped the near-subsurface electrical properties of the levee and the materials immediately below it. The near-subsurface maps provided a better understanding of the levee construction and the nature of the lithology beneath the levee. Comparison of the capacitively coupled resistivity surveys and soil borings indicated that low-resistivity value material composing the levee generally is associated with lean clay and silt to about 2 to 4 meters below the surface, overlying a more resistive layer associated with sand deposits. In general, the resistivity structure becomes more resistive to the south and the southern survey sections correlate well with the borehole data that indicate thinner clay and silt at the surface and thicker sand sequences at depth in these sections. With the resistivity data Omaha Public Power District could focus monitoring efforts on areas with higher resistivity values (coarser-grained deposits or more loosely compacted section), which typically are

Numerical and Experimental Study of Producing Flanges on Hollow Parts by Extrusion with a Movable Sleeve / Badania Teoretyczno-Doświadczalne Procesu Wyciskania Z Zastosowaniem Ruchomej Tulei Kołnierza We Wsadach Drążonych

Directory of Open Access Journals (Sweden)

Gontarz A.

2015-12-01

Full Text Available The paper presents the numerical and experimental results of a new method for producing flanges on hollow parts. With this new method, the flange is extruded by a movable sleeve. This innovative technique is modelled numerically by the finite element method. The effect of workpiece and finished product geometries on the forming process is investigated and failure modes are identfied. The numerical reults are then verified in experiments. The tests are conducted using a three-slide forging press equipped with a special device. The numerical and experimental results show a good agreement, which proves that the developed method is correct.

Study of discharge coefficients of the flapper gates in the Tiete River movable dam; Estudo dos coeficientes de vazao das comportas tipo basculante (CLAPET) da barragem movel do Rio Tiete

Energy Technology Data Exchange (ETDEWEB)

Lucca, Yvone de Faria Lemos de [Universidade de Sao Paulo (CTH/DAEE/USP), SP (Brazil). Departamento de Aguas e Energia Eletrica. Centro Tecnologico de Hidraulica e Recursos Hidricos; Souza, Podalyro Amaral de [Universidade de Sao Paulo (EP/USP), SP (Brazil). Escola Politecnica. Dept. de Aguas e Energia Eletrica], E-mail: podalyro@usp.br

2011-04-15

This article refers to the study of discharge coefficients of the flapper gates in the Tiete River Movable Dam. This dam is made of a reinforced concrete structure with nine flapper gates, which can be operated independently from each other, opening angle from zero to 70 degree. This type of dam structure produces complex flow conditions due to the several opening combinations which make this study very challenging. This paper presents the development of a mathematical model that can estimate the coefficient flow taking into account all major variables present in this dam structure, like the angle of operation of each gate, the approaching flow velocity, the concrete column between gates, the downed outflow effects and the presence of a completely closed gate between two in operation. (author)

Increasing Carbon Loss from Snow-Scoured Alpine Tundra in the Colorado Rocky Mountains: An Indicator of Climate Change?

Science.gov (United States)

Knowles, J. F.; Blanken, P.; Williams, M. W.; Lawrence, C. R.

2015-12-01

We used the eddy covariance method to continuously measure the net ecosystem exchange of carbon dioxide for seven years from a snow-scoured alpine tundra meadow on Niwot Ridge in Colorado, USA that may be underlain by sporadic permafrost. On average, the alpine tundra was a net annual source of 232 g C m-2 to the atmosphere, and the source strength of this ecosystem increased over the length of the seven year period due to both reduced carbon uptake during the growing season and increased respiration throughout the winter. To constrain the contribution of permafrost degradation to observed carbon emissions, we also measured the radiocarbon content of actively cycling, occluded, and mineral soil carbon pools across a meso-scale soil moisture and (possible) permafrost gradient within this meadow, as well as the seasonal radiocarbon content of soil respiration. These data suggest that wintertime soil respiration is limited to patches of wet meadow tundra that may be associated with permafrost. Furthermore, soil respiration from one of these locations indicates preferential turnover of a relatively slow cycling carbon pool during the winter. Given that summer air temperatures and positive degree days have been increasing on Niwot Ridge since the middle of the 20th century, this research suggests that an alpine tundra permafrost-respiration feedback to climate change, similar to that observed in arctic tundra ecosystems, may be currently underway.

Software Engineering with Formal Methods: The Development of a Storm Surge Barrier Control System - Revisiting Seven Myths of Formal Methods

NARCIS (Netherlands)

Tretmans, G.J.; Wijbrans, K.C.J.; Chaudron, M.

2001-01-01

This paper discusses the use of formal methods in the development of the control system for the Maeslant Kering. The Maeslant Kering is the movable dam which has to protect Rotterdam from floodings while, at (almost) the same time, not restricting ship traffic to the port of Rotterdam. The control

Analysis of fourth-grade flat machines with movable close-cycle formed by the rods and two complex links

Directory of Open Access Journals (Sweden)

S.О. Koshel

2016-09-01

Full Text Available Complex multielement mechanisms are increasingly used in the technical equipment of consumer industry. The lack of a universal method of kinematic research of these mechanisms asserts the relevance of work on the kinematic analysis of multielement mechanisms. Aim: The aim of this research is to develop an algorithm kinetic research of velocities of the points that coincide with geometric centers kinematic pairs of structure group of the 4th class and 3rd order with movable close-cycle formed by connecting rod and two complex links. Materials and Methods: The graphic-analytical method of a kinematic research will be used to achieve the goals of research. Development of an algorithm is based on provisions of the theory of mechanisms and engines about property of high classes mechanisms to change its class depending on another possible initial mechanism chosen conditionally which comes to structure of the conducted structural groups of the mechanism links and provisions of theoretical mechanics relatively to instantaneous center of speeds. Results: Velocity vectors of points of Assur group links of the 4th class and 3rd order of the composite flat mechanism are determined by a graphic-analytical method, where the initial mechanism speeds that led to decrease of a class of the mechanism and allowed to investigate it. Unlike the known erroneous statements method which is applied to research the structural groups of the 3rd class, the offered algorithm of the kinematic analysis allows to investigate mechanisms of the 4th class without need to rebuild the plan which was constructed in a uncertain scale, with the subsequent calculation of the real scale parameter of provided plotting of a graph.

Radiation protection in occupational exposure to microwave electrotherapy units; Proteccion radiologica en exposicion ocupacional a microondas en unidades de electroterapia

Energy Technology Data Exchange (ETDEWEB)

Guardia, V.; Ferrer, S.; Alonso, O.; Almonacid, M.

2012-07-01

During the last years, electromagnetic emitters are more and more commonly used for therapeutic treatments in electrotherapy centers. This extended use has caused worries workers, who believe that microwave radiation radiation might have effects similar to those induced by radioactivity, even if the only effects recognised by international regulatory bodies concerning microwave exposure of humans are those of thermal origin. The present study aims to answer the existing concerns about electromagnetic exposure in electrotherapy facilities. After monitoring environmental values in an electrotherapy facility, we conclude that actions must be undertaken in order to reduce the exposure levels, as proposed by the current European guidelines, which should become legally binding for all EU state members within the current year. With the purpose of reducing potential risks of occupational overexposure, we are developing innovative fabrics for microwave shielding. These new materials are able to attenuate 85% of the microwave radiation. As these are light materials, they can be used in all kind of facilities, as wall covers, movable screens or even as personal protection, like lab clothes or gloves. (Author) 6 refs.

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

Bridge abutment; scour depth; riprap; scour holes; river engineering. ... Accurate estimation of the maximum possible depth of scour at bridge abutments is important in decision-making for the safe depth of burial of footings. ... Using this information, an empirical relation was developed for temporal variation of scour depth.

Support and maneuvering device

Science.gov (United States)

Wood, R.L.

1987-03-23

A support and maneuvering device includes an elongated flexible inflatable enclosure having a fixed end and a movable end. The movable end is collapsible toward the fixed end to a contracted position when the enclosure is in a noninflated condition. Upon inflation, the movable end is movable away from the fixed end to an extended position. The movable end includes means for mounting an article such as a solar reflector thereon. The device also includes a plurality of position controlling means disposed about the movable end to effect adjusting movement of portions thereof by predetermined amounts and for controlling an angle at which the article disposed at the movable end is oriented. The plurality of position controlling means limits a suitable number degrees of freedom of the movable end for transmitting a steering motion thereto and for controlling the position thereof. 9 figs.

Instantaneous axial force of a high-order Bessel vortex beam of acoustic waves incident upon a rigid movable sphere.

Science.gov (United States)

Mitri, F G; Fellah, Z E A

2011-08-01

The present investigation examines the instantaneous force resulting from the interaction of an acoustical high-order Bessel vortex beam (HOBVB) with a rigid sphere. The rigid sphere case is important in fluid dynamics applications because it perfectly simulates the interaction of instantaneous sound waves in a reduced gravity environment with a levitated spherical liquid soft drop in air. Here, a closed-form solution for the instantaneous force involving the total pressure field as well as the Bessel beam parameters is obtained for the case of progressive, stationary and quasi-stationary waves. Instantaneous force examples for progressive waves are computed for both a fixed and a movable rigid sphere. The results show how the instantaneous force per unit cross-sectional surface and unit pressure varies versus the dimensionless frequency ka (k is the wave number in the fluid medium and a is the sphere's radius), the half-cone angle β and the order m of the HOBVB. It is demonstrated here that the instantaneous force is determined only for (m,n) = (0,1) (where n is the partial-wave number), and vanishes for m>0 because of symmetry. In addition, the instantaneous force and normalized amplitude velocity results are computed and compared with those of a rigid immovable (fixed) sphere. It is shown that they differ significantly for ka values below 5. The proposed analysis may be of interest in the analysis of instantaneous forces on spherical particles for particle manipulation, filtering, trapping and drug delivery. The presented solutions may also serve as a method for comparison to other solutions obtained by strictly numerical or asymptotic approaches. Copyright © 2011 Elsevier B.V. All rights reserved.

Design of Transition Pieces for Bucket Foundations for Offshore Wind Turbines

DEFF Research Database (Denmark)

Nezhentseva, Anastasia

Using bucket foundations for offshore wind turbines is an alternative solution to monopiles and other foundation types installed in shallow and transitional water depths (up to 50−60 m) due to its greater stiffness, fair simplicity and high speed of installation. However, as only a few prototypes...... was carried out, and the material models were compared in terms of sensitivity to small geometric imperfections that might appear during the fabrication process. This study showed that a TP structure made of pure CRC® was less sensitive to shape imperfections and was recommended in the further investigations...... and the equilibrium scour depth were investigated. Correspondingly, scour protection measures were addressed. Additionally, small-scale hydrodynamic loading tests were carried out on these models in small-scale deep water environment with regular and irregular wave conditions to study the effect of implementation...

Off-season cultivation of capsicums in a solar greenhouse

Energy Technology Data Exchange (ETDEWEB)

Ghosal, M.K.; Tiwari, G.N. [Indian Inst. of Technology, New Delhi (India). Centre for Energy Studies

2001-10-01

The use of solar energy for growing capsicums in pots and in the ground has been studied both under a controlled environment in a solar greenhouse (IIT model) and in an open field during August 2000 to March 2001. Cooling arrangements (natural, forced convection, shading, evaporative cooling) and heating methods (ground air collector, movable insulation during the night) have been employed during the pre-winter and winter periods respectively to maintain the protected environment in the greenhouse. The effects of a north brick wall and the use of movable insulation during the night in the winter months to reduce heat loss from the greenhouse have been incorporated to study the efficacy of the greenhouse. The average height, weight and yield per plant of the greenhouse crop were higher than those of the open field. (author)

Three Dimensional Analysis of the Final Design of Pier Extensions and West Guide Wall to Mitigate Local Scour Risk at the BNSF Railroad Bridge Downstream of the Prado Dam Supplemental Report

Energy Technology Data Exchange (ETDEWEB)

Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Sinha, N. [Argonne National Lab. (ANL), Argonne, IL (United States); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Kerenyi, K. [Turner-Fairbank Highway Research Center, McLean, VA (United States); Sharp, Jeremy [U.S. Army Corps of Engineers, Vicksburg, MI (United States), Coastal and Hydraulics Lab

2016-06-01

This report is a supplement to a previous report [ref] covering optimization of wedge shaped pier extensions to streamline large bluff body piers as a local scour countermeasure for the Burlington Northern and Santa Fe (BNSF) Railroad Bridge over the Santa Ana River downstream of Prado Dam in Riverside County, CA. The optimized design was tested in a 1/30 scale physical model at U.S. Army Engineer Research and Development Center (ERDC) in Vicksburg, MS, and the optimized design was used as the base for the construction design. Constructability issues having to do with both materials and site conditions including access underneath the BNSF bridge yielded a construction design that required making the pier extensions wider and either moving the western curve of the west guide wall upstream or changing its geometry.

Resolving the Role of the Dynamic Pressure in the Burial, Exposure, Scour, and Mobility of Underwater Munitions

Science.gov (United States)

Gilooly, S.; Foster, D. L.

2017-12-01

In nearshore environments, the motion of munitions results from a mixture of sediment transport conditions including sheet flow, scour, bedform migration, and momentary liquefaction. Incipient motion can be caused by disruptive shear stresses and pressure gradients. Foster et al. (2006) incorporated both processes into a single parameter, indicating incipient motion as a function of the bed state. This research looks to evaluate the role of the pressure gradient in positional state changes such as burial, exposure, and mobility. In the case of munitions, this may include pressure gradients induced by vortex shedding or the passing wave. Pressure-mapped model munitions are being developed to measure the orientation, rotation, and surface pressure of the munitions during threshold events leading to a new positional state. These munitions will be deployed in inner surf zone and estuary environments along with acoustic Doppler velocimeters (ADVs), pore water pressure sensors, a laser grid, and a pencil beam sonar with an azimuth drive. The additional instruments allow for near bed and far field water column and sediment bed sampling. Currently preliminary assessments of various pressure sensors and munition designs are underway. Two pressure sensors were selected; the thin FlexiForce A201 sensors will be used to indicate munition rolling during threshold events and diaphragm sensors will be used to understand changes in surrounding pore water pressure as the munition begins to bury/unbury. Both sensors are expected to give quantitative measurements of dynamic pressure gradients in the flow field surrounding the munition. Resolving the role of this process will give insight to an improved incipient motion parameter and allow for better munition motion predictions.

Sediment Dynamics Over a Stable Point bar of the San Pedro River, Southeastern Arizona

Science.gov (United States)

Hamblen, J. M.; Conklin, M. H.

2002-12-01

Streams of the Southwest receive enormous inputs of sediment during storm events in the monsoon season due to the high intensity rainfall and large percentages of exposed soil in the semi-arid landscape. In the Upper San Pedro River, with a watershed area of approximately 3600 square kilometers, particle size ranges from clays to boulders with large fractions of sand and gravel. This study focuses on the mechanics of scour and fill on a stable point bar. An innovative technique using seven co-located scour chains and liquid-filled, load-cell scour sensors characterized sediment dynamics over the point bar during the monsoon season of July to September 2002. The sensors were set in two transects to document sediment dynamics near the head and toe of the bar. Scour sensors record area-averaged sediment depths while scour chains measure scour and fill at a point. The average area covered by each scour sensor is 11.1 square meters. Because scour sensors have never been used in a system similar to the San Pedro, one goal of the study was to test their ability to detect changes in sediment load with time in order to determine the extent of scour and fill during monsoonal storms. Because of the predominantly unconsolidated nature of the substrate it was hypothesized that dune bedforms would develop in events less than the 1-year flood. The weak 2002 monsoon season produced only two storms that completely inundated the point bar, both less than the 1-year flood event. The first event, 34 cms, produced net deposition in areas where Johnson grass had been present and was now buried. The scour sensor at the lowest elevation, in a depression which serves as a secondary channel during storm events, recorded scour during the rising limb of the hydrograph followed by pulses we interpret to be the passage of dunes. The second event, although smaller at 28 cms, resulted from rain more than 50 km upstream and had a much longer peak and a slowly declining falling limb. During the

Mean Flow and Turbulence Near a Series of Dikes

Science.gov (United States)

Yaeger, M. A.; Duan, J. G.

2008-12-01

aid river engineers in designing better bank protection measures and scour-preventing bed pavements around bridge piers, as well as benefiting river restoration projects, since areas around bank protection structures are often habitats for vegetation and fish.

Photomultiplier protector for a fluorometer

International Nuclear Information System (INIS)

Priarone, P.; St John, P.A.

1982-01-01

The photometer is adapted for sensing radiation emitted by a chemical sample held in a cuvette received in a first compartment and includes a highly sensitive photomultiplier in a second compartment adjacent the first compartment for detecting fluorescent radiation emitted by the chemical sample and passing through an opening between the compartments. A mechanical protector assembly is provided for protecting the photomultiplier from ambient light and includes a movable light shield movable between a first position blocking the opening and a second position not blocking the opening. A knob is provided for moving the light shield to the first position to protect the photomultiplier from light entering from the first compartment when the first compartment is opened for insertion or removal of a cuvette, and for moving the light shield to the second position not blocking the opening to permit radiation emitted by the chemical sample to impinge upon the photomultiplier in the second compartment. The photometer also includes a mechanical interlocking assembly for ensuring that the first compartment cannot be opened unless the light shield is in the first position to prevent ambient light from entering the second compartment from the first compartment and reaching the photomultiplier

Development and application of a modified wireless tracer for disaster prevention

Science.gov (United States)

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.

Wecpos - Wave Energy Coastal Protection Oscillating System: A Numerical Assessment

Science.gov (United States)

Dentale, Fabio; Pugliese Carratelli, Eugenio; Rzzo, Gianfranco; Arsie, Ivan; Davide Russo, Salvatore

2010-05-01

In recent years, the interest in developing new technologies to produce energy with low environmental impact by using renewable sources has grown exponentially all over the world. In this context, the experiences made to derive electricity from the sea (currents, waves, etc.) are of particular interest. At the moment, due to the many existing experiments completed or still in progress, it is quite impossible explain what has been obtained but it is worth mentioning the EMEC, which summarizes the major projects in the world. Another important environmental aspect, also related to the maritime field, is the coastal protection from the sea waves. Even in this field, since many years, the structural and non-structural solutions which can counteract this phenomenon are analyzed, in order to cause the least possible damage to the environment. The studies in development by the researchers of the University of Salerno are based on these two aspect previously presented. Considering the technologies currently available, a submerged system has been designed, WECPOS (Wave Energy Coastal Protection Oscillating System), to be located on relatively shallow depths, to can be used simultaneously for both electricity generation and for the coastal protection using the oscillating motion of the water particles. The single element constituting the system is realized by a fixed base and three movable panels that can fluctuate in a fixed angle. The waves interact with the panels generating an alternative motion which can be exploited to produce electricity. At the same time, the constraint movement imposed for the rotation of the panels is a barrier to the wave propagation phenomena, triggering the breaking in the downstream part of the device. So the wave energy will be dissipated obtaining a positive effect for the coastal protection. Currently, the efficiency and effectiveness of the system (WECPOS single module) has been studied by using numerical models. Using the FLOW-3D�

Rapid establishment of phenol- and quinoline-degrading consortia driven by the scoured cake layer in an anaerobic baffled ceramic membrane bioreactor.

Science.gov (United States)

Wang, Wei; Wang, Shun; Ren, Xuesong; Hu, Zhenhu; Yuan, Shoujun

2017-11-01

Although toxic and refractory organics, such as phenol and quinoline, are decomposed by anaerobic bacteria, the establishment of specific degrading consortia is a relatively slow process. An anaerobic membrane bioreactor allows for complete biomass retention that can aid the establishment of phenol- and quinoline-degrading consortia. In this study, the anaerobic digestion of phenol (500 mg L -1 ) and quinoline (50 mg L -1 ) was investigated using an anaerobic baffled ceramic membrane bioreactor (ABCMBR). The results showed that, within 30 days, 99% of phenol, 98% of quinoline and 88% of chemical oxygen demand (COD) were removed. The substrate utilisation rates of the cake layer for phenol and quinoline, and specific methanogenic activity of the cake layer, were 7.58 mg phenol g -1  mixed liquor volatile suspended solids (MLVSS) day -1 , 8.23 mg quinoline g -1  MLVSS day -1 and 0.55 g COD CH4  g -1  MLVSS day -1 , respectively. The contribution of the cake layer to the removals of phenol and quinoline was extremely underestimated because the uncounted scoured cake layer was disregarded. Syntrophus was the key population for phenol and quinoline degradation, and it was more abundant in the cake layer than in the bulk sludge. The highly active scattered cake layer sped up the establishment of phenol- and quinoline-degrading consortia in the ABCMBR.

Two-Dimensional (2-D) Acoustic Fish Tracking at River Mile 85, Sacramento River, California

Science.gov (United States)

2013-06-01

on fish become known (USACE 2004). Levee repair and constructed habitat features included (1) protection of the toe and upper slopes of the bank...be recovered rather than being lost due to sediment dunes , large woody material floating downstream, and vandalism. The RM 85 site was a relatively...into the river channel. The addition of this material narrowed the channel and created a scour feature along the toe of the repair site. VPS array

A Movable Feast

Science.gov (United States)

Waters, John K.

2007-01-01

Mobility and flexibility are the touchstones of 21st-century K-12 architecture, which sets aside conventional classroom design to create an environment that best integrates technology with learning. This article talks about San Jose State University's state-of-the-art, 10,000-square-foot Academic Success Center in California. At the heart of the…

Challenges and Plans for Injection and Beam Dump

Science.gov (United States)

Barnes, M.; Goddard, B.; Mertens, V.; Uythoven, J.

The injection and beam dumping systems of the LHC will need to be upgraded to comply with the requirements of operation with the HL-LHC beams. The elements of the injection system concerned are the fixed and movable absorbers which protect the LHC in case of an injection kicker error and the injection kickers themselves. The beam dumping system elements under study are the absorbers which protect the aperture in case of an asynchronous beam dump and the beam absorber block. The operational limits of these elements and the new developments in the context of the HL-LHC project are described.

Radiation shielding device

International Nuclear Information System (INIS)

Nakagawa, Takahiro; Yamagami, Makoto.

1996-01-01

A fixed shielding member made of a radiation shielding material is constituted in perpendicular to an opening formed on radiation shielding walls. The fixed shielding member has one side opened and has other side, the upper portion and the lower portion disposed in close contact with the radiation shielding walls. Movable shielding members made of a radiation shielding material are each disposed openably on both side of the fixed shielding member. The movable shielding member has a shaft as a fulcrum on one side thereof for connecting it to the radiation shielding walls. The other side has a handle attached for opening/closing the movable shielding member. Upon access of an operator, when each one of the movable shielding members is opened/closed on every time, leakage of linear or scattered radiation can be prevented. Even when both of the movable shielding members are opened simultaneously, the fixed shielding member and the movable shielding members form labyrinth to prevent leakage of linear radioactivity. (I.N.)

Evaluation of Environmental and Hydraulic Performance of Bio-Composite Revetment Blocks

OpenAIRE

Thamer A.  Ahmeed; Nor A.  Alias; Abdul H.  Ghazali; Mohd. S.  Jaafar

2006-01-01

It is necessary to develop a concrete revetment block which can cater for environment and at the same time it will be effective in protecting river banks (stabilize the slope of banks) from scouring during flood. In the present study, the environmental and hydraulic performance of the proposed revetment block was evaluated through laboratory and field tests. The tested revetment block is called bio-composite because it is composed of concrete, plastic mesh and biological material (coconut hus...

The impact of storm events on a riverbed system and its hydraulic conductivity at a site of induced infiltration.

Science.gov (United States)

Levy, Jonathan; Birck, Matthew D; Mutiti, Samuel; Kilroy, Kathryn C; Windeler, Britton; Idris, Ominigho; Allen, Lauren N

2011-08-01

The spatial and temporal variability of riverbed vertical hydraulic conductivity (K(v)) was investigated at a site of induced infiltration, associated with a municipal well field, to assess the impact of high-stage events on scour and subsequently the riverbed K(v). Such impacts are important when considering the potential loss of riverbank filtration capacity due to storm events. The study site, in and along the Great Miami River in southwest Ohio, overlaid a highly productive glacial-outwash aquifer. A three-layer model for this system was conceptualized: a top layer of transient sediment, a second layer comprising large sediment resistant to scour, but clogged with finer sediment (the armor/colmation layer), and a third layer that was transitional to the underlying higher-K(v) aquifer. One location was studied in detail to confirm and quantify the conceptual model. Methods included seepage meters, heat-flow modeling, grain-size analyses, laboratory permeameter tests, slug tests and the use of scour chains and pressure-load cells to directly measure the amount of sediment scour and re-deposition. Seepage meter measured riverbed K(v) ranged from 0.017 to 1.7 m/d with a geometric mean of 0.19 m/d. Heat-transport model-calibrated estimates were even lower, ranging from 0.0061 to 0.046 m/d with a mean of 0.017 m/d. The relatively low K(v) was indicative of the clogged armor layer. In contrast, slug tests in the underlying riverbed sediment yielded K(v) values an order of magnitude greater. There was a linear relationship between scour chain measured scour and event intensity with a maximum scour of only 0.098 m. Load-cell pressure sensor data over a 7-month period indicated a total sediment-height fluctuation of 0.42 m and a maximum storm-event scour of 0.28 m. Scour data indicated that the assumed armor/colmation layer almost always remained intact. Based on measured layer conductivities and thicknesses, the overall K(v) of this conceptualized system was 1.6 m

[Light protection: principles of UV protection].

Science.gov (United States)

Stege, H; Mang, R

2006-05-01

UV radiation is responsible for the induction of epithelial and melanocytic skin cancer, photoaging, and photodermatoses. UV protection is necessary to prevent damage caused by non-physiologic exposure. UV protection includes not only reduction of sun exposure but also use of sun protective filters, UV protective clothes, DNA repair enzymes, and antioxidant supplementation. Consumers are uncertain about the possibilities and limitations of commercial sun protection measures. Dermatologists must explain protective measures to the general public which continues to believe that UV-tanned skin is healthy. The sunscreen market is a highly competitive but lucrative market. The range of products with different designations and promises makes difficult for both consumers and dermatologists to determine what is sensible UV protection.

Protection Coordination in Electrical Substation Part-2 Unit Protections (Differential and Distance Protection)

OpenAIRE

TÜR, Mehmet Rida; Shobole, Abdulfetah; Baysal, Mustafa; Wadi, Mohammed

2018-01-01

Power systemsmust be protected against faults to ensure quality and reliable generation,transmission and distribution of power systems. Power system protection is providedby the protection relays. This paper is the second part of the ProtectionCoordination study for the Siddik Kardesler Substation. The protection fortransmission lines, transformer, bus bars and customer feeders is provided byovercurrent protection, differential and distance protection schemes. In thispaper, issues related wit...

Results of initial nuclear tests on LWBR (LWBR Development Program)

International Nuclear Information System (INIS)

Sarber, W.K.

1979-06-01

This report presents and discusses the results of physics tests performed at beginning of life on the Light Water Breeder Reactor (LWBR). These tests have confirmed that movable seed assembly critical positions and reactivity worths, temperature coefficients, xenon transient characteristics, core symmetry, and core shutdown are within the range of values used in the design of the LWBR and its reactor protection analysis. Measured core physics parameters were found to be in good agreement with the calculated values

Thermosensitive shutter for radioactive source housing

International Nuclear Information System (INIS)

Fullagar, H.

1986-01-01

A shutter apparatus for a radioactive source housing comprises a movable member and a thermosensitive releasing means operative normally to hold the movable member in an open position but to release the movable member to move to a position closing the housing to contain the source when the temperature exceeds a predetermined value, for example as a result of fire. (author)

Applicability of a particularly simple model to nonlinear elasticity of slide-ring gels with movable cross-links as revealed by unequal biaxial deformation.

Science.gov (United States)

Kondo, Yuuki; Urayama, Kenji; Kidowaki, Masatoshi; Mayumi, Koichi; Takigawa, Toshikazu; Ito, Kohzo

2014-10-07

The strain energy density function (F) of the polyrotaxane-based slide-ring (SR) gels with movable cross-links along the network strands is characterized by unequal biaxial stretching which can achieve various types of deformation. The SR gels as prepared without any post-preparation complication exhibit considerably smaller values of the ratio of the stresses (σy/σx) in the stretched (x) and constrained (y) directions in planar extension than classical chemical gels with heterogeneous and nearly homogeneous network structures do. This feature of the SR gels leads to the peculiar characteristic that the strain energy density function (F) has no explicit cross term of strains in different directions, which is in contrast to F with explicit strain cross terms for most chemical gels and elastomers. The biaxial stress-strain data of the SR gels are successfully described by F of the Gent model with only two parameters (small-strain shear modulus and a parameter representing ultimate elongation), which introduces the finite extensibility effect into the neo-Hookean model with no explicit cross term of strain. The biaxial data of the deswollen SR gels examined in previous study, which underwent a considerable reduction in volume from the preparation state, are also well described by the Gent model, which is in contrast to the case of the classical chemical gels that the stress-strain relations before and after large deswelling are not described by a common type of F due to a significant degree of collapse of the network strands in the deswollen state. These intriguing features of nonlinear elasticity of the SR gels originate from a novel function of the slidable cross-links that can maximize the arrangement entropy of cross-linked and non-cross-linked cyclic molecules in the deformed networks.

Red River Waterway, Lock and Dam 3: Report 3 - Sedimentation Conditions Hydraulic Model Investigation

National Research Council Canada - National Science Library

McCollum, Randy

1997-01-01

...) To study tendency for scour and fill in the approaches to the lock and dam and determine training structures that would improve navigation conditions and minimize dredging requirements and scour problems.

A model for capillary rise in micro-tube restrained by a sticky layer

Science.gov (United States)

Shen, Anqi; Xu, Yun; Liu, Yikun; Cai, Bo; Liang, Shuang; Wang, Fengjiao

2018-06-01

Fluid transport in a microscopic capillary under the effects of a sticky layer was theoretically investigated. A model based on the classical Lucas-Washburn (LW) model is proposed for the meniscus rise with the sticky layer present. The sticky layer consists of two parts: a fixed (located at the wall) and a movable part (located on the inside of the capillary), affecting the micro-capillary flow in different ways. Within our model, the movable layer is defined by the capillary radius and pressure gradient. From the model it follows that the fixed sticky layer leads to a decrease of capillary radius, while the movable sticky layer increases flow resistance. The movable layer thickness varies with the pressure gradient, which in turn varies with the rising of the meniscus. The results of our theoretical calculation also prove that the capillary radius has a greater effect on the meniscus height, rather than the additional resistance caused by the movable layer. Moreover, the fixed sticky layer, which affects the capillary radius, has a greater influence than the movable sticky layer. We conclude that the sticky layer causes a lower imbibition height than the LW model predicts.

Offshore Wind Turbines Situated in Areas with Strong Currents

DEFF Research Database (Denmark)

Jensen, Morten S.; Juul Larsen, Brian; Frigaard, Peter

Prediction of local scour caused by offshore wind turbine foundations using empirical formulae or numerical models.......Prediction of local scour caused by offshore wind turbine foundations using empirical formulae or numerical models....

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

Science.gov (United States)

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

Pilot demonstration of energy-efficient membrane bioreactor (MBR) using reciprocating submerged membrane.

Science.gov (United States)

Ho, Jaeho; Smith, Shaleena; Patamasank, Jaren; Tontcheva, Petia; Kim, Gyu Dong; Roh, Hyung Keun

2015-03-01

Membrane bioreactor (MBR) is becoming popular for advanced wastewater treatment and water reuse. Air scouring to "shake" the membrane fibers is most suitable and applicable to maintain filtration without severe and rapidfouling. However, membrane fouling mitigating technologies are energy intensive. The goal of this research is to develop an alternative energy-saving MBR system to reduce energy consumption; a revolutionary system that will directly compete with air scouring technologies currently in the membrane water reuse market. The innovative MBR system, called reciprocation MBR (rMBR), prevents membrane fouling without the use of air scouring blowers. The mechanism featured is a mechanical reciprocating membrane frame that uses inertia to prevent fouling. Direct strong agitation of the fiber is also beneficial for the constant removal of solids built up on the membrane surface. The rMBR pilot consumes less energy than conventional coarse air scouring MBR systems. Specific energy consumption for membrane reciprocation for the pilot rMBR system was 0.072 kWh/m3 permeate produced at 40 LMH, which is 75% less than the conventional air scouring in an MBR system (0.29 kWh/m3). Reciprocation of the hollow-fiber membrane can overcome the hydrodynamic limitations of air scouring or cross-flow membrane systems with less energy consumption and/or higher energy efficiency.

(Another Bankruptcy Legislation reform - functionalization of bankruptcy legal protection or placebo effect?

Directory of Open Access Journals (Sweden)

Dejan Bodul

2015-01-01

Full Text Available The paper deals with the most current topic in the field of collective civil law protection. The reforms of the Bankruptcy Act (seven of them as well as implementation of the Financial Operations and Pre-Bankruptcy Settlements Act (three amendments, which were implemented in 2012, have significantly altered Croatian insolvency legislation. Nevertheless, the indicative methods of determining the facts show that the bankruptcy and preliminary bankruptcy procedures, in relation to other countries in the region, are consuming less time. They are more expensive and have lower satisfaction from creditors. In comparison to countries with developed bankruptcy systems, Croatian regulations still need improvement. One has to take into consideration a substantial impact of multiple external, institutional factors on legislative solutions (unfavourable social context, problems in the payment system, the precarious recordings of immovable and movable property, an insufficient number of judges who were entrusted with the liquidation proceedings, weak training of bankruptcy administrators, inadequate methods of financing, and consequently weak motivation to work. The legislators are planning to make another functionalization of the Bankruptcy Act. His intention is, after two years of experimentation in the Financial Operations and Pre-Bankruptcy Settlements Act, to accept provisions on pre-bankruptcy settlements and reinstate many pre-existing options in the preparation of the reorganization plan. Since the existing framework is not allowing for a detailed analysis of the aforementioned subjects, one must emphasize that the space here does not permit a detailed analysis of these issues. Therefore, authors of this article will deal with subjects they see as relevant and essential for understanding key issues within the domain of the Bankruptcy Act. This work has been supported by the Croatian science foundation under the project number 6558 "Business and

A design of toxic gas detecting security robot car based on wireless path-patrol

Directory of Open Access Journals (Sweden)

Cheng Ho-Chih

2017-01-01

Full Text Available Because a toxic gas detecting/monitoring system in a chemical plant is not movable, a gas detecting/monitoring system will be passive and the detecting range will also be constrained. This invention is an active multi-functional wireless patrol car that can substitute for humans that inspect a plant's security. In addition, to widen the monitoring vision within the environment, two motors used to rotate a wireless IPCAM with two axes are presented. Also, to control the robot car's movement, two axis motors used to drive the wheel of the robot car are also installed. Additionally, a toxic gas detector is linked to the microcontroller of the patrol car. The detected concentration of the gas will be fed back to the server pc. To enhance the robot car's patrolling duration, a movable electrical power unit in conjunction with a wireless module is also used. Consequently, this paper introduces a wireless path-patrol and toxic gas detecting security robot car that can assure a plant's security and protect workers when toxic gases are emitted.

Helios movable Hartmann ball

International Nuclear Information System (INIS)

Tucker, H.E.; Day, R.D.; Hedges, R.O.; Hanlon, J.A.; Kortegaard, B.L.

1981-01-01

The MHB has been in operation for about nine months and has been performing quite well. It has provided the Helios laser fusion facility with additional target illumination flexibility so that many additional parameters can be investigated in the realm of target implosion physics

A surface-micromachining-based inertial micro-switch with compliant cantilever beam as movable electrode for enduring high shock and prolonging contact time

Energy Technology Data Exchange (ETDEWEB)

Xu, Qiu [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Yang, Zhuoqing, E-mail: yzhuoqing@sjtu.edu.cn [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Fu, Bo; Li, Jianhua; Wu, Hao [Huaihai Industrial Group Co., Ltd., Changzhi, Shanxi Province, 046012 (China); Zhang, Qihuan; Sun, Yunna; Ding, Guifu; Zhao, Xiaolin [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China)

2016-11-30

Highlights: • The designed cantilever beam attached to the proof mass can endure a larger shock acceleration (∼1000 g order of magnitude) compared to those traditional designs (∼100 g order of magnitude). • Effect of the pulse width on the threshold acceleration, the response time and the contact time is investigated. • A constraint sleeve structure is introduced to lower the off-axis sensitivity. - Abstract: A novel laterally-driven inertial micro-switch with two L-shaped elastic cantilever beams as the movable electrode, which is attached to the proof mass, is proposed in this paper. The advantage of this design is that the contact time of the inertial micro-switch can be prolonged. Meanwhile, the micro-switch can withstand a higher shock than the traditional designs whose cantilever beams are attached to the fixed electrode. The designed inertial micro-switch was simulated and optimized with ANSYS software and fabricated on a quartz substrate by surface micromachining technology. The simulated result demonstrates that the threshold acceleration (a{sub ths}) under stable switch-on state is about 288 g and the contact time is about 198 μs when the pulse width of acceleration loads is 1 ms. At the same time, it indicates that the threshold acceleration, the response time and the contact time of designed micro-switch all increase with the pulse width of acceleration loads. The simulation of impact process in non-sensitive direction shows that the introduced constraint sleeve structure in the novel inertial micro-switch can lower the off-axis sensitivity. The fabricated micro-switch prototype has been tested by a standard dropping hammer system under shock accelerations with various amplitudes and pulse widths. The experimental measurements show that the contact time is about 150 μs when the threshold acceleration is about 288 g. It also indicates that the response time and the contact time both increase with the pulse width, which is consistent with the

Characterization of major lithologic units underlying the lower American River using water-borne continuous resistivity profiling, Sacramento, California, June 2008

Science.gov (United States)

Ball, Lyndsay B.; Teeple, Andrew

2013-01-01

The levee system of the lower American River in Sacramento, California, is situated above a mixed lithology of alluvial deposits that range from clay to gravel. In addition, sand deposits related to hydraulic mining activities underlie the floodplain and are preferentially prone to scour during high-flow events. In contrast, sections of the American River channel have been observed to be scour resistant. In this study, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, explores the resistivity structure of the American River channel to characterize the extent and thickness of lithologic units that may impact the scour potential of the area. Likely lithologic structures are interpreted, but these interpretations are non-unique and cannot be directly related to scour potential. Additional geotechnical data would provide insightful data on the scour potential of certain lithologic units. Additional interpretation of the resistivity data with respect to these results may improve interpretations of lithology and scour potential throughout the American River channel and floodplain. Resistivity data were collected in three profiles along the American River using a water-borne continuous resistivity profiling technique. After processing and modeling these data, inverted resistivity profiles were used to make interpretations about the extent and thickness of possible lithologic units. In general, an intermittent high-resistivity layer likely indicative of sand or gravel deposits extends to a depth of around 30 feet (9 meters) and is underlain by a consistent low-resistivity layer that likely indicates a high-clay content unit that extends below the depth of investigation (60 feet or 18 meters). Immediately upstream of the Watt Avenue Bridge, the high-resistivity layer is absent, and the low-resistivity layer extends to the surface where a scour-resistant layer has been previously observed in the river bed.

Prenosna peć za pečenje hleba - u funkciji obezbeđenja ishrane pripadnika vojske Srbije u mirovnim misijama/Movable oven for bread baking intended for food preparation in Serbian army peace corps

Directory of Open Access Journals (Sweden)

Branko M. Tešanović

2014-10-01

Full Text Available Peć za pečenje hleba u poljskim uslovima dodeljuje se jedinicama koje su po svom karakteru relativno stacionarne i kojima po veličini ne bi pripadale pokretne peći. Podesna je za pečenje hleba namenjenog jedinicama koje se nalaze u međunarodnim misijama, u uslovima otežanog snabdevanja, jer navike naših vojnika su da konzumiraju hleb, a ne keks. Peć je montažno-demontažnog tipa, prilagođena za korišćenje na svim vrstama terena. Jednostavne je konstrukcije, što omogućava da se demontira i lako prenosi sa mesta na mesto. / An oven for baking bread in field conditions is assigned to units that are by their nature relatively stationary and whose size does not require a movable bakery. It is intended for baking bread in our units located in international missions with supply difficulties, since our units have a habit od consuming bread instead of biscuits. The oven is of a prefabricated type, adapted for use in all types of terrains, simple design which makes it possible to be, dismantled and easily transported.

Electric circuit breaker comprising a plurality of vacuum interrupters simultaneously operated by a common operator

Science.gov (United States)

Barkan, Philip; Imam, Imdad

1980-01-01

This circuit breaker comprises a plurality of a vacuum-type circuit interrupters, each having a movable contact rod. A common operating device for the interrupters comprises a linearly-movable operating member. The interrupters are mounted at one side of the operating member with their movable contact rods extending in a direction generally toward the operating member. Means is provided for mechanically coupling the operating member to the contact rods, and this means comprises a plurality of insulating operating rods, each connected at one end to the operating member and at its opposite end to one of the movable contact rods. The operating rods are of substantially equal length and have longitudinal axes that converge and intersect at substantially a common point.

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

Science.gov (United States)

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

Iceberg killing fields limit huge potential for benthic blue carbon in Antarctic shallows.

Science.gov (United States)

Barnes, David K A

2017-07-01

Climate-forced ice losses are increasing potential for iceberg-seabed collisions, termed ice scour. At Ryder Bay, West Antarctic Peninsula (WAP) sea ice, oceanography, phytoplankton and encrusting zoobenthos have been monitored since 1998. In 2003, grids of seabed markers, covering 225 m 2 , were established, surveyed and replaced annually to measure ice scour frequency. Disturbance history has been recorded for each m 2 of seabed monitored at 5-25 m for ~13 years. Encrusting fauna, collected from impacted and nonimpacted metres each year, show coincident benthos responses in growth, mortality and mass of benthic immobilized carbon. Encrusting benthic growth was mainly determined by microalgal bloom duration; each day, nanophytoplankton exceeded 200 μg L -1 produced ~0.05 mm radial growth of bryozoans, and sea temperature >0 °C added 0.002 mm day -1 . Mortality and persistence of growth, as benthic carbon immobilization, were mainly influenced by ice scour. Nearly 30% of monitored seabed was hit each year, and just 7% of shallows were not hit. Hits in deeper water were more deadly, but less frequent, so mortality decreased with depth. Five-year recovery time doubled benthic carbon stocks. Scour-driven mortality varied annually, with two-thirds of all monitored fauna killed in a single year (2009). Reduced fast ice after 2006 ramped iceberg scouring, killing half the encrusting benthos each year in following years. Ice scour coupled with low phytoplankton biomass drove a phase shift to high mortality and depressed zoobenthic immobilized carbon stocks, which has persevered for 10 years since. Stocks of immobilized benthic carbon averaged nearly 15 g m -2 . WAP ice scouring may be recycling 80 000 tonnes of carbon yr -1 . Without scouring, such carbon would remain immobilized and the 2.3% of shelf which are shallows could be as productive as all the remaining continental shelf. The region's future, when glaciers reach grounding lines and iceberg

Unraveling the channel–lobe transition zone with high-resolution AUV bathymetry: Navy Fan, offshore Baja California, Mexico

Science.gov (United States)

Carvajal, Cristian; Paull, Charles K.; Caress, David W.; Fildani, Andrea; Lundsten, Eve M.; Anderson, Krystle; Maier, Katherine L.; McGann, Mary; Gwiazda, Roberto; Herguera, Juan Carlos

2017-01-01

Ultra-high-resolution (1 m * 1 m * 0.25 m) bathymetry was acquired with an autonomous underwater vehicle (AUV) over a sector of the Navy Fan offshore Baja California. The survey specifically targeted an area where the former interpretation of the fan showed a channel–lobe transition; however, the lobe and the transition were not recognized. Instead, the newly acquired bathymetry shows that the previously identified channel continues basinward changing its overall morphology and stratigraphic architecture, becoming gradually but significantly wider (650–1000 m) and of lower relief (3–4 m). Cores from the channel thalweg recovered mud-poor (< 5%) well-sorted sands, interpreted as deposited by fully turbulent flows. The cores also show several mud-rich (9–18%) poorly sorted sands, probably indicating deposition from more cohesive flows.The high-resolution bathymetry shows large sectors of the seafloor sculpted by elaborate bedforms and scours. The overbank area north of the channel exhibits the most numerous and prominent scours, interpreted to have been largely generated by flow stripping at a bend in the channel. Along high-gradient sectors (more than approximately 1¯) of this area, the scours are largest and deepest. Some of these scours show an erosional headwall and a distal upflow-dipping depositional bulge, forming repetitive bedforms interpreted as erosional cyclic steps associated with locked-in-place trains of hydraulic jumps. The scours seem to coalesce to form an incipient channel, which would likely drive the avulsion of the main channel. Further basinward, average gradients decrease (< 0.6¯ ) and scours become smaller and less deep suggesting a gradient control on erosion. The southern channel margin and adjacent overbank area exhibit a trend of scours that are elongated transverse to flow, that successively repeat themselves basinwards, and that at times merge with sediment waves. Probably these scours are genetically linked to sediment waves

Measures associated with the dose limitation system at the TVO Power Company

International Nuclear Information System (INIS)

Ruuskanen, A.T.; Sundell, R.O.

1982-01-01

The paper discusses radiation protection practices at the TVO Power Company, which owns and operates two BWR units of Asea-Atom design at Olkiluoto, Finland. The installed electric power of each unit is 660MW. The full power operation of TVO I and TVO II began in 1979 and 1980, respectively. The dose limitation system calls for an organization which is responsible for radiation protection. This organization at the plant site is described. To limit doses a good knowledge of the work activities which cause doses is needed. There is a very up-to-date microprocessor-based work dosimetry system at the TVO power plant. The system provides a practicable means of measuring personal doses from various work activities. It also makes the allocation of radiation protection measures possible. The system and experience in applying it are discussed. The dose limitation system presupposes the realization of the optimization principle. The practice applied at TVO in order to limit internal contamination is presented. Owing to this practice, workers' internal doses have remained at a considerably low level. The paper discusses the ALARA values of different kinds of respiratory equipment. These values, which vary from 2x10 4 to 1x10 6 FIM/man.Sv (1 FIM=approx. US$ 0.22), can be used in the evaluation of different measures in avoiding internal doses. The operating policy of movable lead shields is presented. The ALARA value of this activity is evaluated to be about 5x10 4 FIM/man.Sv and on that basis it can be concluded that the use of movable lead shields is very efficient. The dose statistics for TVO's plant are presented. The doses have been less than 0.001 man.Sv/MW.a. Although the dose statistics for TVO are very good it is not realistic to consider solely the optimization aspect of radiation protection. The costs must also be kept in mind; these are presented in the paper. Problems in assessing the level of radiation protection practices on an annual basis are briefly discussed

Long-term remote sensing system for bridge piers and abutments.

Science.gov (United States)

2010-03-01

Scour and other natural hazards have the potential to undermine the stability of piers in highway bridges. This has led to brid : collapse in the past, and significant efforts have been undertaken to address the potential danger of scour and other ha...

Radiation protection in the field of environmental protection

International Nuclear Information System (INIS)

Zhao Yamin

2003-01-01

The relationship of radiation protection with environmental protection, the sources that may give rise to the environmental radiation contamination, and the system of radiation protection and the fundamental principles and requirements for radiation environmental management are introduced. Some special radiation protection problems faced with in the radiation environmental management are discussed. (author)

The morphodynamics and sedimentology of large river confluences

Science.gov (United States)

Nicholas, Andrew; Sambrook Smith, Greg; Best, James; Bull, Jon; Dixon, Simon; Goodbred, Steven; Sarker, Mamin; Vardy, Mark

2017-04-01

Confluences are key locations within large river networks, yet surprisingly little is known about how they migrate and evolve through time. Moreover, because confluence sites are associated with scour pools that are typically several times the mean channel depth, the deposits associated with such scours should have a high potential for preservation within the rock record. However, paradoxically, such scours are rarely observed, and the sedimentological characteristics of such deposits are poorly understood. This study reports results from a physically-based morphodynamic model, which is applied to simulate the evolution and resulting alluvial architecture associated with large river junctions. Boundary conditions within the model simulation are defined to approximate the junction of the Ganges and Jamuna rivers, in Bangladesh. Model results are supplemented by geophysical datasets collected during boat-based surveys at this junction. Simulated deposit characteristics and geophysical datasets are compared with three existing and contrasting conceptual models that have been proposed to represent the sedimentary architecture of confluence scours. Results illustrate that existing conceptual models may be overly simplistic, although elements of each of the three conceptual models are evident in the deposits generated by the numerical simulation. The latter are characterised by several distinct styles of sedimentary fill, which can be linked to particular morphodynamic behaviours. However, the preserved characteristics of simulated confluence deposits vary substantial according to the degree of reworking by channel migration. This may go some way towards explaining the confluence scour paradox; while abundant large scours might be expected in the rock record, they are rarely reported.

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

Science.gov (United States)

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

Digital protection in power plants. Electrical unit and line protection. Digital protection systems for NPP

International Nuclear Information System (INIS)

Kaczmarek, A.

2000-01-01

In this presentation author deals with the digital protection systems for nuclear power plants. The evolution of protection devices, protection concept for power plants, concept of functional redundancy, references for digital protection, benefits for the customer well as concept fault recorder are presented. (author)

Resistor holder

Science.gov (United States)

Broadhurst, John H.

1989-01-01

A resistor device for use with electrostatic particle accelerators includes a resistor element positioned within a tubular housing having a fixed end cap at one end thereof and a movable end cap at the other end thereof. The tubular housing, fixed end cap, and movable end cap serve as an electromagnetic field for the resistor element. Conductive disks engage opposite ends of the resistor element and concentrically position the resistor element within the tubular housing. Helical springs engage the conductive disks and the end caps to yieldably support the movable end caps and resistor element for yieldable axial movement relative to the tubular housing. An annular conducting ring is secured to the tubular housing and is spaced radially from the movable end cap and cooperates with the latter to define an annular spark gap.

An automatic controlled apparatus of target chamber for atomic spectra and level lifetime measurements

International Nuclear Information System (INIS)

Zhao Mengchun; Yang Zhihu

1998-01-01

An automatically controlled apparatus of target chamber was made to measure spectra of the excited atoms and lifetime of the excited levels. The hardware is composed of nine parts including a computer and a step-motor, while the software consists of three branch programs. The maximum movable distance of target position is 65 cm with a step-length of 8.3 μm and a precision of +- 18 μm per 2 mm. On account of simple structure and double protection, the apparatus exhibits flexibility and reliability in years service

Operational radiation protection and radiation protection training

International Nuclear Information System (INIS)

Kraus, W.

1989-01-01

The radiation protection system in the German Democratic Republic (GDR) is reviewed. The competent authority (the SAAS) and its systems of licensing and supervision are described. Discussion covers the role of the Radiation Protection Officer, the types of radiation monitoring, medical surveillance programs and the classification of workers and work areas. Unusual occurrences in the GDR, 1963-1976, are presented and the occupational radiation protection problems at some specific types of workplaces are discussed. The GDR's system of training in radiation protection and nuclear safety is described. 5 figs., 18 tabs

Hydraulic Characteristics of Bedrock Constrictions and Evaluation of One- and Two-Dimensional Models of Flood Flow on the Big Lost River at the Idaho National Engineering and Environmental Laboratory, Idaho

Science.gov (United States)

Berenbrock, Charles; Rousseau, Joseph P.; Twining, Brian V.

2007-01-01

A 1.9-mile reach of the Big Lost River, between the Idaho National Engineering and Environmental Laboratory (INEEL) diversion dam and the Pioneer diversion structures, was investigated to evaluate the effects of streambed erosion and bedrock constrictions on model predictions of water-surface elevations. Two one-dimensional (1-D) models, a fixed-bed surface-water flow model (HEC-RAS) and a movable-bed surface-water flow and sediment-transport model (HEC-6), were used to evaluate these effects. The results of these models were compared to the results of a two-dimensional (2-D) fixed-bed model [Transient Inundation 2-Dimensional (TRIM2D)] that had previously been used to predict water-surface elevations for peak flows with sufficient stage and stream power to erode floodplain terrain features (Holocene inset terraces referred to as BLR#6 and BLR#8) dated at 300 to 500 years old, and an unmodified Pleistocene surface (referred to as the saddle area) dated at 10,000 years old; and to extend the period of record at the Big Lost River streamflow-gaging station near Arco for flood-frequency analyses. The extended record was used to estimate the magnitude of the 100-year flood and the magnitude of floods with return periods as long as 10,000 years. In most cases, the fixed-bed TRIM2D model simulated higher water-surface elevations, shallower flow depths, higher flow velocities, and higher stream powers than the fixed-bed HEC-RAS and movable-bed HEC-6 models for the same peak flows. The HEC-RAS model required flow increases of 83 percent [100 to 183 cubic meters per second (m3/s)], and 45 percent (100 to 145 m3/s) to match TRIM2D simulations of water-surface elevations at two paleoindicator sites that were used to determine peak flows (100 m3/s) with an estimated return period of 300 to 500 years; and an increase of 13 percent (150 to 169 m3/s) to match TRIM2D water-surface elevations at the saddle area that was used to establish the peak flow (150 m3/s) of a paleoflood

Evaluation of protection factor of respiratory protective equipment using indigenously developed protection factor test facility

International Nuclear Information System (INIS)

Patkulkar, D.S.; Ganesh, G.; Tripathi, R.M.

2018-01-01

Assigned protection factor (APF) is an indicator representing effectiveness of a respirator and it provides workplace level of respiratory protection for workers in providing protection against exposure to airborne contaminants Occupational Safety and Health Administration (OSHA) specifies 'Respirator APF' and 'Maximum Use Concentration' (MUC - a term derived using APF) shall be an integral part of Respirator Protection Standard. MUC establishes the maximum airborne concentration of a contaminant in which a respirator with a given APF may be used. The use of particulate respirators such as half face mask, full face mask and powered air purifying respirators is essential for radioactive jobs in nuclear facilities to prevent any intake of radionuclide. With this impetus, the Protection Factor Test Facility (PFTF) for testing and evaluation of respiratory protective equipment meeting relevant applicable standards was designed, fabricated and installed in Respiratory Protective Equipment Laboratory of Health Physics Division

Diplomatic Protection