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Sample records for suspended load collected

  1. Safety Harness For Work Under Suspended Load

    Science.gov (United States)

    Sunoo, Su Young

    1994-01-01

    Safety device protects worker under suspended engine or other heavy load. Mechanically linked with load so if load should fall, worker yanked safely away. Worker wears chest-plate vest with straps crossing eye on back. Lower safety cable connected to eye extends horizontally away from worker to nearby wall, wrapped on pulley and extends upward to motion amplifier or reducer. Safety cables transform any sudden downward motion of overhanging load into rapid sideways motion of worker. Net catches worker, preventing worker from bumping against wall.

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

    Science.gov (United States)

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

    2010-01-01

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

  3. Suspended-sediment loads and reservoir sediment trap efficiency for Clinton Lake, Kansas, 2010-12

    Science.gov (United States)

    Juracek, Kyle E.

    2013-01-01

    Continuous streamflow and turbidity data collected from October 1, 2010, to September 30, 2012, at a site upstream and downstream from Clinton Lake, Kansas, were used to compute the total suspended-sediment load delivered to and released from the reservoir as well as the sediment trap efficiency for the reservoir. Ongoing sedimentation is inhibiting the ability of Clinton Lake to serve several purposes including flood control, water supply, and recreation. The inflow suspended-sediment load was substantially larger than the outflow load and most of the suspended-sediment load was delivered during short-term, high-discharge periods. Respectively, the total 2-year inflow and outflow suspended-sediment loads were computed to be 44.4 and 1.49 million pounds. Sediment trap efficiency for the reservoir was estimated to be 97 percent. The mean annual suspended-sediment yield from the upstream basin was estimated to be 60,500 pounds per square mile. Because this study was completed during a drought, the estimated inflow suspended-sediment load and suspended-sediment yield likely are substantially less than what would occur during a period of average or above average precipitation and runoff.

  4. An analysis of bedload and suspended load interactions

    Science.gov (United States)

    Recking, alain; Navratil, Oldrich

    2013-04-01

    Several approaches were used to develop suspension equations. It includes semi-theoretical equations based on the convection diffusion equation (Einstein 1950; Van Rijn 1984; Camenen and Larson 2008; Julien 2010), semi-empirical tools based on energy concept (Velikanov 1954; Bagnold 1966), empirical adjustments (Prosser and Rusttomji 2000). One essential characteristic of all these equations is that most of them were developed by considering continuity between bedload and suspended load, and that the partitioning between these two modes of transport evolves progressively with increasing shear stress, which is the case for fine bed materials. The use of these equations is thus likely to be welcome in estuaries or lowland sandy rivers, but may be questionable in gravel-bed rivers and headwater streams where the bed is usually structured vertically and fine sediments potentially contributing to suspension are stored under a poorly mobile surface armour comprising coarse sediments. Thus one question this work aimed to answer is does the presence of an armour at the bed surface influence suspended load? This was investigated through a large field data set comprising instantaneous measurements of both bedload and suspension. We also considered the river characteristics, distinguishing between lowland rivers, gravel bed rivers and headwater streams. The results showed that a correlation exist between bedload and suspension for lowland and gravel bed rivers. This suggests that in gravel bed rivers a large part of the suspended load is fed by subsurface material, and depends on the remobilization of the surface material. No correlation was observed for head water streams where the sediment production is more likely related to hillslope processes. These results were used with a bedload transport equation for proposing a method for suspended load estimate. The method is rough, but especially for gravel bed rivers, it predicts suspended load reasonably well when compared to

  5. Quantifying suspended sediment loads delivered to Cheney Reservoir, Kansas: Temporal patterns and management implications

    Science.gov (United States)

    Stone, Mandy L.; Juracek, Kyle E.; Graham, Jennifer; Foster, Guy

    2015-01-01

    Cheney Reservoir, constructed during 1962 to 1965, is the primary water supply for the city of Wichita, the largest city in Kansas. Sediment is an important concern for the reservoir as it degrades water quality and progressively decreases water storage capacity. Long-term data collection provided a unique opportunity to estimate the annual suspended sediment loads for the entire history of the reservoir. To quantify and characterize sediment loading to Cheney Reservoir, discrete suspended sediment samples and continuously measured streamflow data were collected from the North Fork Ninnescah River, the primary inflow to Cheney Reservoir, over a 48-year period. Continuous turbidity data also were collected over a 15-year period. These data were used together to develop simple linear regression models to compute continuous suspended sediment concentrations and loads from 1966 to 2013. The inclusion of turbidity as an additional explanatory variable with streamflow improved regression model diagnostics and increased the amount of variability in suspended sediment concentration explained by 14%. Using suspended sediment concentration from the streamflow-only model, the average annual suspended sediment load was 102,517 t (113,006 tn) and ranged from 4,826 t (5,320 tn) in 1966 to 967,569 t (1,066,562 tn) in 1979. The sediment load in 1979 accounted for about 20% of the total load over the 48-year history of the reservoir and 92% of the 1979 sediment load occurred in one 24-hour period during a 1% annual exceedance probability flow event (104-year flood). Nearly 60% of the reservoir sediment load during the 48-year study period occurred in 5 years with extreme flow events (9% to 1% annual exceedance probability, or 11- to 104-year flood events). A substantial portion (41%) of sediment was transported to the reservoir during five storm events spanning only eight 24-hour periods during 1966 to 2013. Annual suspended sediment load estimates based on streamflow were, on

  6. Muscular contribution to low-back loading and stiffness during standard and suspended push-ups.

    Science.gov (United States)

    Beach, Tyson A C; Howarth, Samuel J; Callaghan, Jack P

    2008-06-01

    Push-up exercises are normally performed to challenge muscles that span upper extremity joints. However, it is also recognized that push-ups provide an effective abdominal muscle challenge, especially when the hands are in contact with a labile support surface. The purpose of this study was to compare trunk muscle activation levels and resultant intervertebral joint (IVJ) loading when standard and suspended push-ups were performed, and to quantify and compare the contribution of trunk muscles to IVJ rotational stiffness in both exercises. Eleven recreationally trained male volunteers performed sets of standard and suspended push-ups. Upper body kinematic, kinetic, and EMG data were collected and input into a 3D biomechanical model of the lumbar torso to quantify lumbar IVJ loading and the contributions of trunk muscles to IVJ rotational stiffness. When performing suspended push-ups, muscles of the abdominal wall and the latissimus dorsi were activated to levels that were significantly greater than those elicited when performing standard push-ups (pups. Also directly resulting from the increased activation levels of the abdominal muscles and the latissimus dorsi during suspended push-ups was increased muscular contribution to lumbar IVJ rotational stiffness (pups appear to provide a superior abdominal muscle challenge. However, for individuals unable to tolerate high lumbar IVJ compressive loads, potential benefits gained by incorporating suspended push-ups into their resistance training regimen may be outweighed by the risk of overloading low-back tissues.

  7. Suspended-sediment and nutrient loads for Waiakea and Alenaio Streams, Hilo, Hawaii, 2003-2006

    Science.gov (United States)

    Presley, Todd K.; Jamison, Marcael T.J.; Nishimoto, Dale C.

    2008-01-01

    Suspended sediment and nutrient samples were collected during wet-weather conditions at three sites on two ephemeral streams in the vicinity of Hilo, Hawaii during March 2004 to March 2006. Two sites were sampled on Waiakea Stream at 80- and 860-foot altitudes during March 2004 to August 2005. One site was sampled on Alenaio Stream at 10-foot altitude during November 2005 to March 2006. The sites were selected to represent different land uses and land covers in the area. Most of the drainage area above the upper Waiakea Stream site is conservation land. The drainage areas above the lower site on Waiakea Stream, and the site on Alenaio Stream, are a combination of conservation land, agriculture, rural, and urban land uses. In addition to the sampling, continuous-record streamflow sites were established at the three sampling sites, as well as an additional site on Alenaio Stream at altitude of 75 feet and 0.47 miles upstream from the sampling site. Stage was measured continuously at 15-minute intervals at these sites. Discharge, for any particular instant, or for selected periods of time, were computed based on a stage-discharge relation determined from individual discharge measurements. Continuous records of discharge were computed at the two sites on Waiakea Stream and the upper site on Aleniao Stream. Due to non-ideal hydraulic conditions within the channel of Alenaio Stream, a continuous record of discharge was not computed at the lower site on Alenaio Stream where samples were taken. Samples were analyzed for suspended sediment, and the nutrients total nitrogen, dissolved nitrite plus nitrate, and total phosphorus. Concentration data were converted to instantaneous load values: loads are the product of discharge and concentration, and are presented as tons per day for suspended sediment or pounds per day for nutrients. Daily-mean loads were computed by estimating concentrations relative to discharge using graphical constituent loading analysis techniques. Daily

  8. Suspended-sediment and suspended-sand concentrations and loads for selected streams in the Mississippi River Basin, 1940-2009

    Science.gov (United States)

    Heimann, David C.; Cline, Teri L.; Glaspie, Lori M.

    2011-01-01

    This report presents suspended-sediment concentration and streamflow data, describes load-estimation techniques used in the computation of annual suspended-sediment loads, and presents annual suspended-sediment loads for 48 streamgaging stations within the Mississippi River Basin. Available published, unpublished, and computed annual total suspended-sediment and suspended-sand loads are presented for water years 1940 through 2009. When previously published annual loads were not available, total suspended-sediment and sand loads were computed using available data for water years 1949 through 2009. A table of suspended-sediment concentration and daily mean streamflow data used in the computation of annual loads is presented along with a table of compiled and computed annual suspended-sediment and suspended-sand loads, annual streamflows, and flow-weighted concentrations for the 48 stations.

  9. Elemental Composition of Suspended Particulate Matter Collected ...

    African Journals Online (AJOL)

    The samples were analysed by energy dispersive x-ray fluorescence (EDXRF) and atomic absorption spectroscopy (AAS) for up to 10 elements. It was found that 66% of the samples collected at two metres and 50% of the samples collected at four metres height exceeded the WHO 24 guideline of 70μg m-3. Reduction in ...

  10. An assessment of the suspended sediment rating curve approach for load estimation on the Rivers Bandon and Owenabue, Ireland

    Science.gov (United States)

    Harrington, Seán T.; Harrington, Joseph R.

    2013-03-01

    This paper presents an assessment of the suspended sediment rating curve approach for load estimation on the Rivers Bandon and Owenabue in Ireland. The rivers, located in the South of Ireland, are underlain by sandstone, limestones and mudstones, and the catchments are primarily agricultural. A comprehensive database of suspended sediment data is not available for rivers in Ireland. For such situations, it is common to estimate suspended sediment concentrations from the flow rate using the suspended sediment rating curve approach. These rating curves are most commonly constructed by applying linear regression to the logarithms of flow and suspended sediment concentration or by applying a power curve to normal data. Both methods are assessed in this paper for the Rivers Bandon and Owenabue. Turbidity-based suspended sediment loads are presented for each river based on continuous (15 min) flow data and the use of turbidity as a surrogate for suspended sediment concentration is investigated. A database of paired flow rate and suspended sediment concentration values, collected between the years 2004 and 2011, is used to generate rating curves for each river. From these, suspended sediment load estimates using the rating curve approach are estimated and compared to the turbidity based loads for each river. Loads are also estimated using stage and seasonally separated rating curves and daily flow data, for comparison purposes. The most accurate load estimate on the River Bandon is found using a stage separated power curve, while the most accurate load estimate on the River Owenabue is found using a general power curve. Maximum full monthly errors of - 76% to + 63% are found on the River Bandon with errors of - 65% to + 359% found on the River Owenabue. The average monthly error on the River Bandon is - 12% with an average error of + 87% on the River Owenabue. The use of daily flow data in the load estimation process does not result in a significant loss of accuracy on

  11. Loads of nitrate, phosphorus, and total suspended solids from Indiana watersheds

    Science.gov (United States)

    Bunch, Aubrey R.

    2016-01-01

    Transport of excess nutrients and total suspended solids (TSS) such as sediment by freshwater systems has led to degradation of aquatic ecosystems around the world. Nutrient and TSS loads from Midwestern states to the Mississippi River are a major contributor to the Gulf of Mexico Hypoxic Zone, an area of very low dissolved oxygen concentration in the Gulf of Mexico. To better understand Indiana’s contribution of nutrients and TSS to the Mississippi River, annual loads of nitrate plus nitrite as nitrogen, total phosphorus, and TSS were calculated for nine selected watersheds in Indiana using the load estimation model, S-LOADEST. Discrete water-quality samples collected monthly by the Indiana Department of Environmental Management’s Fixed Stations Monitoring Program from 2000–2010 and concurrent discharge data from the U. S. Geological Survey streamflow gages were used to create load models. Annual nutrient and TSS loads varied across Indiana by watershed and hydrologic condition. Understanding the loads from large river sites in Indiana is important for assessing contributions of nutrients and TSS to the Mississippi River Basin and in determining the effectiveness of best management practices in the state. Additionally, evaluation of loads from smaller upstream watersheds is important to characterize improvements at the local level and to identify priorities for reduction.

  12. Suspended-sediment concentrations, loads, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011

    Science.gov (United States)

    Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.

    2014-01-01

    Sediment-laden rivers and streams pose substantial environmental and economic challenges. Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, and transports harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentrations (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples collected from 14 sites from 2007 through 2011 indicated that the Zumbro River at Kellogg in the driftless region of southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. During the 2011 spring runoff, the single highest SSC of 1,250 mg/L was measured at the Zumbro River. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis- St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been determined to underrepresent the amount of suspended sediment. Because of this, the MPCA was interested in quantifying the differences between SSC and TSS in different parts of the State. Comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. The largest percent difference between SSC and TSS was measured at the South Branch Buffalo River at Sabin, and the smallest difference was observed at the Des Moines

  13. Basic hydraulic experiment on the saturated concentration of suspended load due to tsunamis

    Science.gov (United States)

    Takahashi, Tomoyuki; Somekawa, Shiho

    2016-04-01

    When tsunamis arrive in the shallow sea, a huge amount of suspended load is generated by large velocity and strong turbulence. The suspended load causes the geomorphic processes of erosion and deposition. Because the suspended load cannot be increased endlessly, it should have the saturated concentration. Many numerical models of sediment transport due to tsunamis have assumed a constant value of 1% for the saturated concentration empirically. However, it is supposed as a function of velocity. In this study, a hydraulic experiment was carried out to investigate a relationship between velocity and the saturated concentration of suspended load when tsunamis attack. A water circulation pipe used in the experiment was 10 cm in a diameter, 260 cm in length and 50 cm in width. A velocity of water flow in the pipe had been controlled by two pumps and two valves. It was changed from 0.24 to 1.22 m/s. Various amounts of sand was spread on the bottom of pipe. The amount of sand was changed from 0.1 to 10% as converted in the concentration of suspended load if all sand suspended. A diameter and a density of the sand were 0.267 mm and 2.64 x 103 kg/m^3. A condition of sediment transport in the pipe was recorded by video camera from a transparent window at the side of pipe. The condition was judged as all sand particles were suspended or not. The former condition indicates that the concentration of suspended load is saturated and the latter does it is not saturated. When velocity was smaller than 0.47 m/s, there was no suspended load because of a weak tractive force. When velocity became larger, the suspended load was generated and the concentration also became higher. However, the concentration had the upper limit and surplus sand appeared on the bed of pipe when velocity became much larger. The condition gave the saturated concentration of suspended load. When velocity was 0.665 m/s, the saturated concentration was smaller than 1% which is used in many numerical simulations

  14. Chlorophyll 'a' particulate organic carbon and suspended load from the mangrove areas of Cochin backwaters

    Digital Repository Service at National Institute of Oceanography (India)

    Sheeba, P.; Devi, K.S.; Balasubramanian, T.; Sankaranarayanan, V.N.

    Chlorophyll 'a' Particulate Organic Carbon and suspended load were estimated for one year from two distinct mangrove areas of Cochin backwaters, viz. Puthuvypeen and Nettoor. Environmental parameters like tau degrees C, S ppt and pH were also...

  15. Annual suspended-sediment loads in the Colorado River near Cisco, Utah, 1930-82

    Science.gov (United States)

    Thompson, K.R.

    1985-01-01

    The Colorado River upstream of gaging station 09180500 near Cisco, Utah, drains about 24,100 square miles in Utah and Colorado. Altitudes in the basin range from 12,480 feet near the headwaters to 4,090 feet at station 09180500. The average annual precipitation for 1894-1982 near the station was 7.94 inches. The average annual precipitation near the headwaters often exceeds 50 inches. Rocks ranging in age from Precambrian to Holocene are exposed in the drainage basin upstream from station 09180500. Shale, limestone, siltstone, mudstone, and sandstone probably are the most easily eroded rocks in the basin, and they contribute large quantities of sediment to the Colorado River. During 1930-82, the U.S. Geological Survey collected records of fluvial sediment at station 09180500. Based on these records, the mean annual suspended-sediment load was 11,390,000 tone, ranging from 2,038,000 tons in water year 1981 to 35,700,000 tons in water year 1938. The minimum daily load of 14 tons was on August 22, 1960, and the maximum daily load of 2,790,000 tons was on October 14, 1941. (USGS)

  16. Recent Trends in Suspended Sediment Load & Water Quality in the Upper Chesapeake Bay

    Science.gov (United States)

    Freeman, L. A.; Ackleson, S. G.

    2016-02-01

    The Chesapeake Bay spans several major cities on the US east coast and drains a large watershed (164,200 km2) to the Atlantic Ocean. Upstream deforestation and agriculture have led to a major decline in water quality (increased sediment and nutrient load) of the Bay over the past century. Sediment flux into the Chesapeake Bay is a natural process, but has become an environmental concern as land use changes have exacerbated natural suspended sediment loads and saturated the capacity of the estuary to filter and remove sediments. In situ measurements of suspended sediments and surface reflectance from the Potomac, Patapsco, and Severn River were used to develop algorithms that convert surface reflectance from Landsat (1-3, 4-5, 7, 8) imagery to suspended sediment concentration for the entire Chesapeake Bay. A unique time series of suspended sediment load in the Chesapeake Bay was compiled from Landsat imagery dating from 1977-2015. Particular focus is given to the upper Chesapeake Bay near Washington, DC and Baltimore, MD to understand urban effects. In particular, the Potomac, Patapsco, and Severn River are examined from both remote sensing and in situ measurements. Landsat imagery combined with in situ monitoring provides environmental scientists and resource managers with detailed trends in sediment distribution and concentration, a key measure of water quality. Trends of suspended sediment load in several rivers and the upper Chesapeake Bay will be presented, along with a discussion of suspended sediment algorithms for Landsat imagery. Advantages of Landsat 8 (improved signal-to-noise performance and more bands) versus previous sensors will be examined for suspended sediment applications.

  17. Suspended-sediment loads in the lower Stillaguamish River, Snohomish County, Washington, 2014–15

    Science.gov (United States)

    Anderson, Scott A.; Curran, Christopher A.; Grossman, Eric E.

    2017-08-03

    Continuous records of discharge and turbidity at a U.S. Geological Survey (USGS) streamgage in the lower Stillaguamish River were paired with discrete measurements of suspended-sediment concentration (SSC) in order to estimate suspended-sediment loads over the water years 2014 and 2015. First, relations between turbidity and SSC were developed and used to translate the continuous turbidity record into a continuous estimate of SSC. Those concentrations were then used to predict suspended-sediment loads based on the current discharge record, reported at daily intervals. Alternative methods were used to in-fill a small number of days with either missing periods of turbidity or discharge records. Uncertainties in our predictions at daily and annual time scales were estimated based on the parameter uncertainties in our turbidity-SSC regressions. Daily loads ranged from as high as 121,000 tons during a large autumn storm to as low as –56 tons, when tidal return flow moved more sediment upstream than river discharge did downstream. Annual suspended-sediment loads for both water years were close to 1.4 ± 0.2 million tons.

  18. A comparison of selection at list time and time-stratified sampling for estimating suspended sediment loads

    Science.gov (United States)

    Robert B. Thomas; Jack Lewis

    1993-01-01

    Time-stratified sampling of sediment for estimating suspended load is introduced and compared to selection at list time (SALT) sampling. Both methods provide unbiased estimates of load and variance. The magnitude of the variance of the two methods is compared using five storm populations of suspended sediment flux derived from turbidity data. Under like conditions,...

  19. Analyzing the uncertainty of suspended sediment load prediction using sequential data assimilation

    Science.gov (United States)

    Leisenring, Marc; Moradkhani, Hamid

    2012-10-01

    SummaryA first step in understanding the impacts of sediment and controlling the sources of sediment is to quantify the mass loading. Since mass loading is the product of flow and concentration, the quantification of loads first requires the quantification of runoff volume. Using the National Weather Service's SNOW-17 and the Sacramento Soil Moisture Accounting (SAC-SMA) models, this study employed particle filter based Bayesian data assimilation methods to predict seasonal snow water equivalent (SWE) and runoff within a small watershed in the Lake Tahoe Basin located in California, USA. A procedure was developed to scale the variance multipliers (a.k.a hyperparameters) for model parameters and predictions based on the accuracy of the mean predictions relative to the ensemble spread. In addition, an online bias correction algorithm based on the lagged average bias was implemented to detect and correct for systematic bias in model forecasts prior to updating with the particle filter. Both of these methods significantly improved the performance of the particle filter without requiring excessively wide prediction bounds. The flow ensemble was linked to a non-linear regression model that was used to predict suspended sediment concentrations (SSCs) based on runoff rate and time of year. Runoff volumes and SSC were then combined to produce an ensemble of suspended sediment load estimates. Annual suspended sediment loads for the 5 years of simulation were finally computed along with 95% prediction intervals that account for uncertainty in both the SSC regression model and flow rate estimates. Understanding the uncertainty associated with annual suspended sediment load predictions is critical for making sound watershed management decisions aimed at maintaining the exceptional clarity of Lake Tahoe. The computational methods developed and applied in this research could assist with similar studies where it is important to quantify the predictive uncertainty of pollutant load

  20. Temporal variability in the suspended sediment load and streamflow of the Doce River

    Science.gov (United States)

    Oliveira, Kyssyanne Samihra Santos; Quaresma, Valéria da Silva

    2017-10-01

    Long-term records of streamflow and suspended sediment load provide a better understanding of the evolution of a river mouth, and its adjacent waters and a support for mitigation programs associated with extreme events and engineering projects. The aim of this study is to investigate the temporal variability in the suspended sediment load and streamflow of the Doce River to the Atlantic Ocean, between 1990 and 2013. Streamflow and suspended sediment load were analyzed at the daily, seasonal, and interannual scales. The results showed that at the daily scale, Doce River flood events are due to high intensity and short duration rainfalls, which means that there is a flashy response to rainfall. At the monthly and season scales, approximately 94% of the suspended sediment supply occurs during the wet season. Extreme hydrological events are important for the interannual scale for Doce River sediment supply to the Atlantic Ocean. The results suggest that a summation of anthropogenic interferences (deforestation, urbanization and soil degradation) led to an increase of extreme hydrological events. The findings of this study shows the importance of understanding the typical behavior of the Doce River, allowing the detection of extreme hydrological conditions, its causes and possible environmental and social consequences.

  1. A spatially explicit suspended-sediment load model for western Oregon

    Science.gov (United States)

    Wise, Daniel R.; O'Connor, Jim

    2016-06-27

    We calibrated the watershed model SPARROW (Spatially Referenced Regressions on Watershed attributes) to give estimates of suspended-sediment loads for western Oregon and parts of northwestern California. Estimates of suspended-sediment loads were derived from a nonlinear least squares regression that related explanatory variables representing landscape and transport conditions to measured suspended-sediment loads at 68 measurement stations. The model gives estimates of model coefficients and their uncertainty within a spatial framework defined by the National Hydrography Dataset Plus hydrologic network. The resulting model explained 64 percent of the variability in suspended-sediment yield and had a root mean squared error value of 0.737. The predictor variables selected for the final model were (1) generalized lithologic province, (2) mean annual precipitation, and (3) burned area (by recent wildfire). Other landscape characteristics also were considered, but they were not significant predictors of sediment transport, were strongly correlated with another predictor variable, or were not as significant as the predictors selected for the final model.

  2. Guidelines and Procedures for Computing Time-Series Suspended-Sediment Concentrations and Loads from In-Stream Turbidity-Sensor and Streamflow Data

    Science.gov (United States)

    Rasmussen, Patrick P.; Gray, John R.; Glysson, G. Douglas; Ziegler, Andrew C.

    2009-01-01

    In-stream continuous turbidity and streamflow data, calibrated with measured suspended-sediment concentration data, can be used to compute a time series of suspended-sediment concentration and load at a stream site. Development of a simple linear (ordinary least squares) regression model for computing suspended-sediment concentrations from instantaneous turbidity data is the first step in the computation process. If the model standard percentage error (MSPE) of the simple linear regression model meets a minimum criterion, this model should be used to compute a time series of suspended-sediment concentrations. Otherwise, a multiple linear regression model using paired instantaneous turbidity and streamflow data is developed and compared to the simple regression model. If the inclusion of the streamflow variable proves to be statistically significant and the uncertainty associated with the multiple regression model results in an improvement over that for the simple linear model, the turbidity-streamflow multiple linear regression model should be used to compute a suspended-sediment concentration time series. The computed concentration time series is subsequently used with its paired streamflow time series to compute suspended-sediment loads by standard U.S. Geological Survey techniques. Once an acceptable regression model is developed, it can be used to compute suspended-sediment concentration beyond the period of record used in model development with proper ongoing collection and analysis of calibration samples. Regression models to compute suspended-sediment concentrations are generally site specific and should never be considered static, but they represent a set period in a continually dynamic system in which additional data will help verify any change in sediment load, type, and source.

  3. Concentration Measurements of Suspended Load using ADV with Influence of the Particle Size

    Science.gov (United States)

    Schwarzwälder, Kordula

    2017-04-01

    ADV backscatter data can be used under certain conditions to gain information about the concentrations of suspended loads. This was shown in many studies before (Fugate and Friedrichs 2002; Chanson et al 2008; Ha et al. 2009). This paper reports on a pre-study to investigate the influence of particle size on concentration measurements for suspended sediment load with ADV. The study was conducted in a flume in the Oskar-von-Miller-Institute using fresh water from a river including the natural suspended load. The ADV used in the experiments was a Vectrino Profiler (Nortek). In addition water samples were taken for TSS and TOC. For the measurements a surge was generated in the flume to ensure that also particles of larger size will be present in the water phase. The measurements and samples were taken during the whole surge event. Therefore we were able to find a good correlation between the backscatter data of the ADV and the TSS as well as TOC results. For the decreasing part of the flow event the concentration of TOC in the suspended load of the water phase is decreasing much slower than the TSS and results in a damped decrease of the backscatter values. This means that the results for concentration measurements might be slightly influenced by the size of the particles. Further evaluations of measurements conducted with a LISST SL (Sequoia) will be investigated to show the trend of the particle sizes during this process and fortify this result. David C. Fugate, Carl T. Friedrichs, Determining concentration and fall velocity of estuarine particle populations using ADV, OBS and LISST, Continental Shelf Research, Volume 22, Issues 11-13, 2002 H.K. Ha, W.-Y. Hsu, J.P.-Y. Maa, Y.Y. Shao, C.W. Holland, Using ADV backscatter strength for measuring suspended cohesive sediment concentration, Continental Shelf Research, Volume 29, Issue 10, 2009 Hubert Chanson, Maiko Takeuchi, Mark Trevethan, Using turbidity and acoustic backscatter intensity as surrogate measures of

  4. Transport of phosphorus, wash load and suspended sediment in the River Varde A in southwest Jutland, Denmark

    DEFF Research Database (Denmark)

    Thodsen, Hans; Hasholt, Bent; Pejrup, Morten

    2004-01-01

    Total phosphorus (TP) concentrations, suspended sediment concentrations (SSC) and wash load have been measured at three river monitoring stations in the River Varde Angstrom system since 1998. This provides the possibility of studying the link between SSC and wash load and concentrations of TP....... Transport rates of TP, suspended sediment and wash load at the three stations, calculated using rating curves, indicate the dependence of TP transport on the transport of suspended sediment and wash load. Two stations are located on tributaries flowing upstream of the third station located at a weir...... at the end of a small impoundment. Transport rates at the upstream stations were 57% higher for suspended sediment and 27% higher for wash load than at the downstream station, while transport of TP was the same. This indicates that phosphorus is transported adhered to the finest grain size fractions that do...

  5. Sources of suspended-sediment loads in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary, south Texas, 1958–2010

    Science.gov (United States)

    Ockerman, Darwin J.; Heitmuller, Franklin T.; Wehmeyer, Loren L.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; City of Corpus Christi; Guadalupe-Blanco River Authority; San Antonio River Authority; and San Antonio Water System, developed, calibrated, and tested a Hydrological Simulation Program-FORTRAN (HSPF) watershed model to simulate streamflow and suspended-sediment concentrations and loads during 1958-2010 in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary in south Texas. Data available to simulate suspended-sediment concentrations and loads consisted of historical sediment data collected during 1942-82 in the study area and suspended-sediment concentration data collected periodically by the USGS during 2006-7 and 2010 at three USGS streamflow-gaging stations (08211000 Nueces River near Mathis, Tex. [the Mathis gage], 08211200 Nueces River at Bluntzer, Tex. [the Bluntzer gage], and 08211500 Nueces River at Calallen, Tex. [the Calallen gage]), and at one ungaged location on a Nueces River tributary (USGS station 08211050 Bayou Creek at Farm Road 666 near Mathis, Tex.). The Mathis gage is downstream from Wesley E. Seale Dam, which was completed in 1958 to impound Lake Corpus Christi. Suspended-sediment data collected before and after completion of Wesley E. Seale Dam provide insights to the effects of the dam and reservoir on suspended-sediment loads transported by the lower Nueces River downstream from the dam to the Nueces Estuary. Annual suspended-sediment loads at the Nueces River near the Mathis, Tex., gage were considerably lower for a given annual mean discharge after the dam was completed than before the dam was completed.

  6. Nutrient, suspended sediment, and trace element loads in the Blackstone River Basin in Massachusetts and Rhode Island, 2007 to 2009

    Science.gov (United States)

    Zimmerman, Marc J.; Waldron, Marcus C.; DeSimone, Leslie A.

    2015-01-01

    Nutrients, suspended sediment, and trace element loads in the Blackstone River and selected tributaries were estimated from composite water-quality samples in order to better understand the distribution and sources of these constituents in the river basin. The flow-proportional composite water-quality samples were collected during sequential 2-week periods at six stations along the river’s main stem, at three stations on tributaries, and at four wastewater treatment plants in the Massachusetts segment of the basin from June 2007 to September 2009. Samples were collected at an additional station on the Blackstone River near the mouth in Pawtucket, Rhode Island, from September 2008 to September 2009. The flow-proportional composite samples were used to estimate average daily loads during the sampling periods; annual loads for water years 2008 and 2009 also were estimated for the monitoring station on the Blackstone River near the Massachusetts-Rhode Island border. The effects of hydrologic conditions and net attenuation of nitrogen were investigated for loads in the Massachusetts segment of the basin. Sediment resuspension and contaminant loading dynamics were evaluated in two Blackstone River impoundments, the former Rockdale Pond (a breached impoundment) and Rice City Pond.

  7. Stabilization of a Quadrotor With Uncertain Suspended Load Using Sliding Mode Control

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xu; Liu, Rui; Zhang, Jiucai; Zhang, Xiaoli

    2016-08-21

    The stability and trajectory control of a quadrotor carrying a suspended load with a fixed known mass has been extensively studied in recent years. However, the load mass is not always known beforehand in practical applications. This mass uncertainty brings uncertain disturbances to the quadrotor system, causing existing controllers to have a worse performance or to be collapsed. To improve the quadrotor's stability in this situation, we investigate the impacts of the uncertain load mass on the quadrotor. By comparing the simulation results of two controllers -- the proportional-derivative (PD) controller and the sliding mode controller (SMC) driven by a sliding mode disturbance of observer (SMDO), the quadrotor's performance is verified to be worse as the uncertainty increases. The simulation results also show a controller with stronger robustness against disturbances is better for practical applications.

  8. 14 CFR 1261.416 - Suspending or terminating collection action.

    Science.gov (United States)

    2010-01-01

    ... and is unable to make payments on the Government's claim or effect a compromise at the time, but the... applicable statute of limitations has been tolled or started running anew; or (ii) Future collection can be...'s inability to pay, the following factors, among others, may be considered: Age and health of the...

  9. Continuous-flow centrifugation to collect suspended sediment for chemical analysis

    Science.gov (United States)

    Conn, Kathleen E.; Dinicola, Richard S.; Black, Robert W.; Cox, Stephen E.; Sheibley, Richard W.; Foreman, James R.; Senter, Craig A.; Peterson, Norman T.

    2016-12-22

    Recent advances in suspended-sediment monitoring tools and surrogate technologies have greatly improved the ability to quantify suspended-sediment concentrations and to estimate daily, seasonal, and annual suspended-sediment fluxes from rivers to coastal waters. However, little is known about the chemical composition of suspended sediment, and how it may vary spatially between water bodies and temporally within a single system owing to climate, seasonality, land use, and other natural and anthropogenic drivers. Many water-quality contaminants, such as organic and inorganic chemicals, nutrients, and pathogens, preferentially partition in sediment rather than water. Suspended sediment-bound chemical concentrations may be undetected during analysis of unfiltered water samples, owing to small water sample volumes and analytical limitations. Quantification of suspended sediment‑bound chemical concentrations is needed to improve estimates of total chemical concentrations, chemical fluxes, and exposure levels of aquatic organisms and humans in receiving environments. Despite these needs, few studies or monitoring programs measure the chemical composition of suspended sediment, largely owing to the difficulty in consistently obtaining samples of sufficient quality and quantity for laboratory analysis.A field protocol is described here utilizing continuous‑flow centrifugation for the collection of suspended sediment for chemical analysis. The centrifuge used for development of this method is small, lightweight, and portable for the field applications described in this protocol. Project scoping considerations, deployment of equipment and system layout options, and results from various field and laboratory quality control experiments are described. The testing confirmed the applicability of the protocol for the determination of many inorganic and organic chemicals sorbed on suspended sediment, including metals, pesticides, polycyclic aromatic hydrocarbons, and

  10. Suspended-sediment loads, reservoir sediment trap efficiency, and upstream and downstream channel stability for Kanopolis and Tuttle Creek Lakes, Kansas, 2008-10

    Science.gov (United States)

    Juracek, Kyle E.

    2011-01-01

    Continuous streamflow and turbidity data collected from October 1, 2008, to September 30, 2010, at streamgage sites upstream and downstream from Kanopolis and Tuttle Creek Lakes, Kansas, were used to compute the total suspended-sediment load delivered to and released from each reservoir as well as the sediment trap efficiency for each reservoir. Ongoing sedimentation is decreasing the ability of the reservoirs to serve several purposes including flood control, water supply, and recreation. River channel stability upstream and downstream from the reservoirs was assessed using historical streamgage information. For Kanopolis Lake, the total 2-year inflow suspended-sediment load was computed to be 600 million pounds. Most of the suspended-sediment load was delivered during short-term, high-discharge periods. The total 2-year outflow suspended-sediment load was computed to be 31 million pounds. Sediment trap efficiency for the reservoir was estimated to be 95 percent. The mean annual suspended-sediment yield from the upstream basin was estimated to be 129,000 pounds per square mile per year. No pronounced changes in channel width were evident at five streamgage sites located upstream from the reservoir. At the Ellsworth streamgage site, located upstream from the reservoir, long-term channel-bed aggradation was followed by a period of stability. Current (2010) conditions at five streamgages located upstream from the reservoir were typified by channel-bed stability. At the Langley streamgage site, located immediately downstream from the reservoir, the channel bed degraded 6.15 feet from 1948 to 2010. For Tuttle Creek Lake, the total 2-year inflow suspended-sediment load was computed to be 13.3 billion pounds. Most of the suspended-sediment load was delivered during short-term, high-discharge periods. The total 2-year outflow suspended-sediment load was computed to be 327 million pounds. Sediment trap efficiency for the reservoir was estimated to be 98 percent. The mean

  11. Development of an axial suspended AMB experimental bench for load and disturbance tests

    Directory of Open Access Journals (Sweden)

    R. Gouws

    2015-06-01

    Full Text Available This paper provides the development of an axial suspended active magnetic bearing (AMB experimental bench for load and disturbance tests. This test bench must be capable of levitating a 2 kg steel disc at a stable working distance of 3 mm and a maximum attraction distance of 6 mm. The suspension is accomplished by two electromagnets producing upward and downward attraction forces to support the steel disc. An inductive sensor measures the position of the steel disc and relays this to a PC based controller board (dSPACE® controller. The control system uses this information to regulate the electromagnetic force on the steel disc. The intent is to construct this system using relatively low-cost, low-precision components, and still be able to stably levitate the 2 kg steel disc with high precision. The dSPACE® software (ControlDesk® was used for data acquisition. In this paper, an overview of the system design is presented, followed by the axial AMB model design, inductive sensor design, actuating unit design and controller development and implementation. The paper concludes with results obtained from the dSPACE® controller and evaluation of the axial suspended AMB experimental bench with load and disturbance tests.

  12. Concentrations, loads, and yields of total phosphorus, total nitrogen, and suspended sediment and bacteria concentrations in the Wister Lake Basin, Oklahoma and Arkansas, 2011-13

    Science.gov (United States)

    Buck, Stephanie D.

    2014-01-01

    The Poteau Valley Improvement Authority uses Wister Lake in southeastern Oklahoma as a public water supply. Total phosphorus, total nitrogen, and suspended sediments from agricultural runoff and discharges from wastewater treatment plants and other sources have degraded water quality in the lake. As lake-water quality has degraded, water-treatment cost, chemical usage, and sludge production have increased for the Poteau Valley Improvement Authority. The U.S. Geological Survey (USGS), in cooperation with the Poteau Valley Improvement Authority, investigated and summarized concentrations of total phosphorus, total nitrogen, suspended sediment, and bacteria (Escherichia coli and Enterococcus sp.) in surface water flowing to Wister Lake. Estimates of total phosphorus, total nitrogen, and suspended sediment loads, yields, and flow-weighted mean concentrations of total phosphorus and total nitrogen concentrations were made for the Wister Lake Basin for a 3-year period from October 2010 through September 2013. Data from water samples collected at fixed time increments during base-flow conditions and during runoff conditions at the Poteau River at Loving, Okla. (USGS station 07247015), the Poteau River near Heavener, Okla. (USGS station 07247350), and the Fourche Maline near Leflore, Okla. (USGS station 07247650), water-quality stations were used to evaluate water quality over the range of streamflows in the basin. These data also were collected to estimate annual constituent loads and yields by using regression models. At the Poteau River stations, total phosphorus, total nitrogen, and suspended sediment concentrations in surface-water samples were significantly larger in samples collected during runoff conditions than in samples collected during base-flow conditions. At the Fourche Maline station, in contrast, concentrations of these constituents in water samples collected during runoff conditions were not significantly larger than concentrations during base

  13. 7 CFR 3.20 - Standards for suspending or terminating collection activities.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Standards for suspending or terminating collection activities. 3.20 Section 3.20 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT Standards... authorized or required by law. ...

  14. Evaluating external nutrient and suspended-sediment loads to Upper Klamath Lake, Oregon, using surrogate regressions with real-time turbidity and acoustic backscatter data

    Science.gov (United States)

    Schenk, Liam N.; Anderson, Chauncey W.; Diaz, Paul; Stewart, Marc A.

    2016-12-22

    Executive SummarySuspended-sediment and total phosphorus loads were computed for two sites in the Upper Klamath Basin on the Wood and Williamson Rivers, the two main tributaries to Upper Klamath Lake. High temporal resolution turbidity and acoustic backscatter data were used to develop surrogate regression models to compute instantaneous concentrations and loads on these rivers. Regression models for the Williamson River site showed strong correlations of turbidity with total phosphorus and suspended-sediment concentrations (adjusted coefficients of determination [Adj R2]=0.73 and 0.95, respectively). Regression models for the Wood River site had relatively poor, although statistically significant, relations of turbidity with total phosphorus, and turbidity and acoustic backscatter with suspended sediment concentration, with high prediction uncertainty. Total phosphorus loads for the partial 2014 water year (excluding October and November 2013) were 39 and 28 metric tons for the Williamson and Wood Rivers, respectively. These values are within the low range of phosphorus loads computed for these rivers from prior studies using water-quality data collected by the Klamath Tribes. The 2014 partial year total phosphorus loads on the Williamson and Wood Rivers are assumed to be biased low because of the absence of data from the first 2 months of water year 2014, and the drought conditions that were prevalent during that water year. Therefore, total phosphorus and suspended-sediment loads in this report should be considered as representative of a low-water year for the two study sites. Comparing loads from the Williamson and Wood River monitoring sites for November 2013–September 2014 shows that the Williamson and Sprague Rivers combined, as measured at the Williamson River site, contributed substantially more suspended sediment to Upper Klamath Lake than the Wood River, with 4,360 and 1,450 metric tons measured, respectively.Surrogate techniques have proven useful at

  15. Computing time-series suspended-sediment concentrations and loads from in-stream turbidity-sensor and streamflow data

    Science.gov (United States)

    Rasmussen, Patrick P.; Gray, John R.; Glysson, G. Doug; Ziegler, Andrew C.

    2010-01-01

    Over the last decade, use of a method for computing suspended-sediment concentration and loads using turbidity sensors—primarily nephelometry, but also optical backscatter—has proliferated. Because an in- itu turbidity sensor is capa le of measuring turbidity instantaneously, a turbidity time series can be recorded and related directly to time-varying suspended-sediment concentrations. Depending on the suspended-sediment characteristics of the measurement site, this method can be more reliable and, in many cases, a more accurate means for computing suspended-sediment concentrations and loads than traditional U.S. Geological Survey computational methods. Guidelines and procedures for estimating time s ries of suspended-sediment concentration and loading as a function of turbidity and streamflow data have been published in a U.S. Geological Survey Techniques and Methods Report, Book 3, Chapter C4. This paper is a summary of these guidelines and discusses some of the concepts, s atistical procedures, and techniques used to maintain a multiyear suspended sediment time series.

  16. Trend of suspended sediment load in the Velika Morava River in the period 1967-2007

    Directory of Open Access Journals (Sweden)

    Mustafić Sanja

    2014-01-01

    Full Text Available The paper is concerned with identifying changes in the time series of discharge (Q, suspended sediment concentration (SSC and sediment load (Qs of the Velika Morva River. The catchment area on farthest hydrological profile Ljubičevski most on Velika Morava River is approximately 35,496 km2. In this profile were carried out daily measurements of flow and concetration of silt in the period from 1967 to 2007. Average perennial transport of suspended sediment is 2.57ˣ106 t (72.4 t/km2/yr and ranged from 0.17ˣ106 t (4.8 t/km2/yr to 10.02ˣ106 t (282.2 t/km2/yr. Trends determined for Q, SSC and Qs are statistically obtained using the non-parametric Mann-Kendall test. Results of Mann-Kendall test show that Q has a slight declining trend of annual values which do not show statistical significance. Decline in trendline SSC and Qs is a significant at the level of 0.01. Calculating the standardized regression coefficients, it was found that the relative impact of SSC on sediment load is 3.1 time higher than the impact of discharge. From 1967 to 2007 the average decrease in sediment load at the mouth of the Velika Morava into the Danube was 3.1 t/km2/yr. [Projekat Ministarstva nauke Republike Srbije, br. 43007: The Research on Climate Change Influences on Environment: Influence Monitoring, Adaptation and Mitigation, subproject No. 9: Torrential Floods Frequency, Soil and Water Degradation as the Consequence of Global Changes

  17. Anti-Swing Control of Suspended Loads on Shipboard Robotic Cranes

    Directory of Open Access Journals (Sweden)

    Jackrit Suthakorn

    2005-02-01

    Full Text Available Currently, the speed at which materials can be transferred between ships at sea is limited by sea conditions. Rough sea conditions cause the payload to swing making load transfer difficult and time-consuming. The objective of this research is to develop a real-time, command compensating control for reducing sea state induced payload swing for shipboard robotic cranes. The future use of this control strategy will be to facilitate faster "ship-to-ship" payload transfer in rough sea conditions. In this study, only the sea-induced rotational motion of the ship is considered, since it is assumed that a station-keeping control maintains a constant position of the ship. This rotational motion is modelled using pitch-yaw-roll Euler angles. The shipboard robotic crane is modelled as a spherical pendulum attached to a three-degree-of-freedom manipulator. The three degrees-of-freedom are azimuth (rotation about an axis normal to the ship's deck, elevation (rotation about an axis parallel with the ship's deck, also referred to as luffing, and lift-line length. An inverse kinematics based approach and a sliding mode control strategy are explored. Both approaches use the azimuth and the elevation capability of the crane manipulator to maintain a horizontal position of the suspended load to reduce sea-induced payload sway.

  18. Transport and exchange of U-series nuclides between suspended material, dissolved load and colloids in rivers draining basaltic terrains

    Science.gov (United States)

    Pogge von Strandmann, Philip A. E.; Burton, Kevin W.; Porcelli, Don; James, Rachael H.; van Calsteren, Peter; Gislason, Sigurður R.

    2011-01-01

    This study presents uranium and thorium concentrations and activity ratios for all riverine phases (bedload, suspended load, dissolved load and colloids) from basaltic terrains in Iceland and the Azores. Small basaltic islands, such as these, are thought to account for ~ 25% of CO2 consumed by global silicate weathering, and for ~ 45% of the flux of suspended material to the oceans. These data indicate that [U] and [Th] in the dissolved and colloidal fractions are strongly controlled by pH, and to a much lesser extent by levels of dissolved organic carbon (which are low in these environments). At high pH, basalt glass dissolution is enhanced, and secondary mineral formation (e.g. Fe-oxyhydroxides and allophane) is suppressed, resulting in high dissolved [U], and low colloidal [U] and [Th], indicating a direct chemical weathering control on elemental abundances. When the dissolved (234U/238U) activity ratio is >~1.3 (i.e. when physical weathering, groundwater contribution or soil formation are high), there is little isotope exchange between dissolved and colloidal fractions. At lower activity ratios, the dissolved load and colloids have indistinguishable activity ratios, suggesting that when chemical weathering rates are high, secondary clay formation is also high, and colloids rapidly adsorb dissolved U. Many of the suspended sediment samples have (234U/238U) activity ratios of > 1, which suggests that uptake of U onto the suspended load is important. Identical (230Th/232Th) in suspended, dissolved and colloidal samples suggests that Th, like U, is exchanged or sorbed rapidly between all riverine phases. This particle-reactivity, combined with poorly constrained contributions from groundwater and hydrothermal water, and short-term variations in input to soils (volcanic and glacial), suggests that U-series nuclides in riverine material from such basaltic terrains are unlikely to reflect steady state erosion processes.

  19. THE HYDROLOGIC CYCLE, UNIDIRECTIONAL CHARTER OF THE DISSOLVED SALTS AND SUSPENDED LOAD

    Directory of Open Access Journals (Sweden)

    Nicolae Florea

    2012-12-01

    Full Text Available In this paper it is underlined that the hydrologic cycle in nature, reversible and regenerating of fresh water, carries out also an unidirectional and irreversible circulation – by means of a fragment of the hydrologic cycle – of the dissolved salts and stream’s suspended load, entailed by the water drained from continents to ocean. The trend is to transfer soluble salts from land to ocean in the same time with the running water on land in the portion of the hydrologic cycle which refers to the water transfer from continents to ocean in order to equilibrate the annual water balance of the hydrologic cycle. But, one can realize here and there some local salt accumulations in salt soils or in salt lakes within areas without drainage in arid climate; these salts accumulations are cases of local hydrologic cycles „grafted” along the way of water on land (to ocean. The energy necessary to the hydrologic cycle in nature is delivered by the Sun, and the entropy remains at a low level as a consequence of the elimination in this cycle of water vapors with high entropy, and of the receiving of liquid or solid water with low entropy, so that the annual level of entropy is maintained at a low level.

  20. Suspended-sediment concentrations, bedload, particle sizes, surrogate measurements, and annual sediment loads for selected sites in the lower Minnesota River Basin, water years 2011 through 2016

    Science.gov (United States)

    Groten, Joel T.; Ellison, Christopher A.; Hendrickson, Jon S.

    2016-12-20

    Accurate measurements of fluvial sediment are important for assessing stream ecological health, calculating flood levels, computing sediment budgets, and managing and protecting water resources. Sediment-enriched rivers in Minnesota are a concern among Federal, State, and local governments because turbidity and sediment-laden waters are the leading impairments and affect more than 6,000 miles of rivers in Minnesota. The suspended sediment in the lower Minnesota River is deleterious, contributing about 75 to 90 percent of the suspended sediment being deposited into Lake Pepin. The Saint Paul District of the U.S. Army Corps of Engineers and the Lower Minnesota River Watershed District collaborate to maintain a navigation channel on the lower 14.7 miles of the Minnesota River through scheduled dredging operations. The Minnesota Pollution Control Agency has adopted a sediment-reduction strategy to reduce sediment in the Minnesota River by 90 percent by 2040.The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, the Minnesota Pollution Control Agency, and the Lower Minnesota River Watershed District, collected suspended-sediment, bedload, and particle-size samples at five sites in the lower Minnesota River Basin during water years 2011 through 2014 and surrogate measurements of acoustic backscatter at one of these sites on the lower Minnesota River during water years 2012 through 2016 to quantify sediment loads and improve understanding of sediment-transport relations. Annual sediment loads were computed for calendar years 2011 through 2014.Data collected from water years 2011 through 2014 indicated that two tributaries, Le Sueur River and High Island Creek, had the highest sediment yield and concentrations of suspended sediment. These tributaries also had greater stream gradients than the sites on the Minnesota River. Suspended fines were greater than suspended sand at all sites in the study area. The range of median particle sizes matched

  1. Spatial and temporal trends in estimates of nutrient and suspended sediment loads in the Ishikari River, Japan, 1985 to 2010.

    Science.gov (United States)

    Duan, Weili; Takara, Kaoru; He, Bin; Luo, Pingping; Nover, Daniel; Yamashiki, Yosuke

    2013-09-01

    Nutrients and suspended sediment in surface water play important roles in aquatic ecosystems and contribute strongly to water quality with implication for drinking water resources, human and environmental health. Estimating loads of nutrients (nitrogen and phosphorus) and suspended sediment (SS) is complicated because of infrequent monitoring data, retransformation bias, data censoring, and non-normality. To obtain reliable unbiased estimates, the Maintenance of Variance-Extension type 3 (MOVE. 3) and the regression model Load Estimator (LOADEST) were applied to develop regression equations and to estimate total nitrogen (TN), total phosphorus (TP) and SS loads at five sites on the Ishikari River, Japan, from 1985 to 2010. Coefficients of determination (R(2)) for the best-fit regression models for loads of TN, TP, and SS for the five sites ranged from 71.86% to 90.94%, suggesting the model for all three constituents successfully simulated the variability in constituent loads at all studied sites. Estimated monthly average loads at Yishikarikakou-bashi were larger than at the other sites, with TN, TP, and SS loads ranging from 8.52×10(3) to 2.00×10(5) kg/day (Apr. 1999), 3.96×10(2) to 5.23×10(4) kg/ day (Apr. 1999), and 9.21×10(4) to 9.25×10(7) kg/day (Sep. 2001), respectively. Because of variation in river discharge, the estimated seasonal loads fluctuated widely over the period 1985 to 2010, with the greatest loads occurring in spring and the smallest loads occurring in winter. Estimated loads of TN, TP, and especially SS showed decreasing trends during the study period. Accurate load estimation is a necessary goal of water quality monitoring efforts and the methods described here provide essential information for effectively managing water resources. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. An urban observatory for quantifying phosphorus and suspended solid loads in combined natural and stormwater conveyances.

    Science.gov (United States)

    Melcher, Anthony A; Horsburgh, Jeffery S

    2017-06-01

    Water quality in urban streams and stormwater systems is highly dynamic, both spatially and temporally, and can change drastically during storm events. Infrequent grab samples commonly collected for estimating pollutant loadings are insufficient to characterize water quality in many urban water systems. In situ water quality measurements are being used as surrogates for continuous pollutant load estimates; however, relatively few studies have tested the validity of surrogate indicators in urban stormwater conveyances. In this paper, we describe an observatory aimed at demonstrating the infrastructure required for surrogate monitoring in urban water systems and for capturing the dynamic behavior of stormwater-driven pollutant loads. We describe the instrumentation of multiple, autonomous water quality and quantity monitoring sites within an urban observatory. We also describe smart and adaptive sampling procedures implemented to improve data collection for developing surrogate relationships and for capturing the temporal and spatial variability of pollutant loading events in urban watersheds. Results show that the observatory is able to capture short-duration storm events within multiple catchments and, through inter-site communication, sampling efforts can be synchronized across multiple monitoring sites.

  3. 15 CFR 19.8 - When will Commerce entities suspend or terminate debt collection on a Commerce debt?

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false When will Commerce entities suspend or terminate debt collection on a Commerce debt? 19.8 Section 19.8 Commerce and Foreign Trade Office of the Secretary of Commerce COMMERCE DEBT COLLECTION Procedures To Collect Commerce Debts § 19.8 When will...

  4. 36 CFR 1011.8 - When will the Presidio Trust suspend or terminate debt collection on a debt?

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false When will the Presidio Trust suspend or terminate debt collection on a debt? 1011.8 Section 1011.8 Parks, Forests, and Public Property PRESIDIO TRUST DEBT COLLECTION Procedures To Collect Presidio Trust Debts § 1011.8 When will the Presidio...

  5. Characterization of Suspended-Sediment Loading to and from John Redmond Reservoir, East-Central Kansas, 2007-2008

    Science.gov (United States)

    Lee, Casey J.; Rasmussen, Patrick P.; Ziegler, Andrew C.

    2008-01-01

    Storage capacity in John Redmond Reservoir is being lost to sedimentation more rapidly than in other federal impoundments in Kansas. The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, initiated a study to characterize suspended-sediment loading to and from John Redmond Reservoir from February 21, 2007, through February 21, 2008. Turbidity sensors were installed at two U.S. Geological Survey stream gages upstream (Neosho River near Americus and the Cottonwood River near Plymouth) and one stream gage downstream (Neosho River at Burlington) from the reservoir to compute continuous, real-time (15-minute) measurements of suspended-sediment concentration and loading. About 1,120,000 tons of suspended-sediment were transported to, and 100,700 tons were transported from John Redmond Reservoir during the study period. Dependent on the bulk density of sediment stored in the reservoir, 5.0 to 1.4 percent of the storage in the John Redmond conservation pool was lost during the study period, with an average deposition of 3.4 to 1.0 inches. Nearly all (98-99 percent) of the incoming sediment load was transported during 9 storms which occurred 25 to 27 percent of the time. The largest storm during the study period (peak-flow recurrence interval of about 4.6-4.9 years) transported about 37 percent of the sediment load to the reservoir. Suspended-sediment yield from the unregulated drainage area upstream from the Neosho River near Americus was 530 tons per square mile, compared to 400 tons per square mile upstream from the Cottonwood River near Plymouth. Comparison of historical (1964-78) to current (2007) sediment loading estimates indicate statistically insignificant (99 percent) decrease in sediment loading at the Neosho River at Burlington. Ninety-percent confidence intervals of streamflow-derived estimates of total sediment load were 7 to 21 times larger than turbidity-derived estimates. Results from this study can be used by natural resource

  6. Suspended particulate matter collection methods influence the quantification of polycyclic aromatic compounds in the river system.

    Science.gov (United States)

    Abuhelou, Fayez; Mansuy-Huault, Laurence; Lorgeoux, Catherine; Catteloin, Delphine; Collin, Valéry; Bauer, Allan; Kanbar, Hussein Jaafar; Gley, Renaud; Manceau, Luc; Thomas, Fabien; Montargès-Pelletier, Emmanuelle

    2017-08-16

    In this study, we compared the influence of two different collection methods, filtration (FT) and continuous flow field centrifugation (CFC), on the concentration and the distribution of polycyclic aromatic compounds (PACs) in suspended particulate matter (SPM) occurring in river waters. SPM samples were collected simultaneously with FT and CFC from a river during six sampling campaigns over 2 years, covering different hydrological contexts. SPM samples were analyzed to determine the concentration of PACs including 16 polycyclic aromatic hydrocarbons (PAHs), 11 oxygenated PACs (O-PACs), and 5 nitrogen PACs (N-PACs). Results showed significant differences between the two separation methods. In half of the sampling campaigns, PAC concentrations differed from a factor 2 to 30 comparing FT and CFC-collected SPMs. The PAC distributions were also affected by the separation method. FT-collected SPM were enriched in 2-3 ring PACs whereas CFC-collected SPM had PAC distributions dominated by medium to high molecular weight compounds typical of combustion processes. This could be explained by distinct cut-off threshold of the two separation methods and strongly suggested the retention of colloidal and/or fine matter on glass-fiber filters particularly enriched in low molecular PACs. These differences between FT and CFC were not systematic but rather enhanced by high water flow rates.

  7. Fatigue Performance Assessment of Composite Arch Bridge Suspenders Based on Actual Vehicle Loads

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-01-01

    Full Text Available In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders.

  8. A novel method for sampling the suspended sediment load in the tidal environment using bi-directional time-integrated mass-flux sediment (TIMS) samplers

    Science.gov (United States)

    Elliott, Emily A.; Monbureau, Elaine; Walters, Glenn W.; Elliott, Mark A.; McKee, Brent A.; Rodriguez, Antonio B.

    2017-12-01

    Identifying the source and abundance of sediment transported within tidal creeks is essential for studying the connectivity between coastal watersheds and estuaries. The fine-grained suspended sediment load (SSL) makes up a substantial portion of the total sediment load carried within an estuarine system and efficient sampling of the SSL is critical to our understanding of nutrient and contaminant transport, anthropogenic influence, and the effects of climate. Unfortunately, traditional methods of sampling the SSL, including instantaneous measurements and automatic samplers, can be labor intensive, expensive and often yield insufficient mass for comprehensive geochemical analysis. In estuaries this issue is even more pronounced due to bi-directional tidal flow. This study tests the efficacy of a time-integrated mass sediment sampler (TIMS) design, originally developed for uni-directional flow within the fluvial environment, modified in this work for implementation the tidal environment under bi-directional flow conditions. Our new TIMS design utilizes an 'L' shaped outflow tube to prevent backflow, and when deployed in mirrored pairs, each sampler collects sediment uniquely in one direction of tidal flow. Laboratory flume experiments using dye and particle image velocimetry (PIV) were used to characterize the flow within the sampler, specifically, to quantify the settling velocities and identify stagnation points. Further laboratory tests of sediment indicate that bidirectional TIMS capture up to 96% of incoming SSL across a range of flow velocities (0.3-0.6 m s-1). The modified TIMS design was tested in the field at two distinct sampling locations within the tidal zone. Single-time point suspended sediment samples were collected at high and low tide and compared to time-integrated suspended sediment samples collected by the bi-directional TIMS over the same four-day period. Particle-size composition from the bi-directional TIMS were representative of the array of

  9. Simulation of streamflow and suspended-sediment concentrations and loads in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary, South Texas, 1958-2008

    Science.gov (United States)

    Ockerman, Darwin J.; Heitmuller, Franklin T.

    2010-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers-Fort Worth District, City of Corpus Christi, Guadalupe-Blanco River Authority, San Antonio River Authority, and San Antonio Water System, developed, calibrated, and tested a Hydrological Simulation Program ? FORTRAN (HSPF) watershed model to simulate streamflow and suspended-sediment concentrations and loads during 1958-2008 in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary in South Texas. Data available to simulate suspended-sediment concentrations and loads consisted of historical sediment data collected during 1942-82 in the study area and suspended-sediment concentration data collected periodically by the USGS during 2006-07 at three USGS streamflow-gaging stations, Nueces River near Mathis, Nueces River at Bluntzer, and Nueces River at Calallen. The Nueces River near Mathis station is downstream from Wesley E. Seale Dam, completed in 1958 to impound Lake Corpus Christi. Suspended-sediment data collected before and after completion of Wesley E. Seale Dam provide insights to the effects of the dam and reservoir on suspended-sediment loads transported by the lower Nueces River from downstream of the dam to the Nueces Estuary. Annual suspended-sediment loads at a site near the Nueces River at Mathis station were considerably lower, for a given annual mean discharge, after the dam was completed than before the dam was completed. Most of the suspended sediment transported by the Nueces River downstream from Wesley E. Seale Dam occurred during high-flow releases from the dam or during floods. During October 1964-September 1971, about 532,000 tons of suspended sediment were transported by the Nueces River near Mathis. Of this amount, about 473,000 tons, or about 89 percent, were transported by large runoff events (mean streamflow exceeding 1,000 cubic feet per second). To develop the watershed model to simulate suspended

  10. Impact of sampling frequency on mean concentrations and estimated loads of suspended sediment in a Norwegian river: implications for water management.

    Science.gov (United States)

    Skarbøvik, Eva; Stålnacke, Per; Bogen, Jim; Bønsnes, Truls E

    2012-09-01

    Reliable estimates of mean concentrations and loads of pollutants in rivers have become increasingly important for management purposes, particularly with the implementation of the European Union Water Framework Directive (WFD). Here, the Numedalslågen River (5500 km(2)) in southern Norway was used as a case study to evaluate the effects of sampling frequency on mean concentrations and estimated loads of suspended particulate matter (SPM). Daily monitoring data from five seasons (April/June-October/November 2001-2005) were analyzed, and three different load estimation techniques were tested: rating curves, linear interpolation, and the ratio method. The reliability of mean SPM concentrations improved with increasing sampling frequency, but even weekly sampling gave error rates as high as 70% in seasons with elevated sediment loads. Load estimates varied considerably depending on both the sampling frequency and the calculation method used. None of the methods provided consistently good results, but the lowest error rate was achieved when using the rating curve on data from fortnightly sampling and additional sampling during floods. Sampling at monthly intervals gave the highest error rates and cannot be recommended for any of the calculation methods applied here. SPM concentrations were correlated (r(2)>0.5) with arsenic, lead, nickel, orthophosphate, and total phosphorus in the Numedalslågen River. Therefore, the current findings may also have implications for substances other than SPM. The discussion considers examples from actual use of infrequently collected data, and it is advised that managers account for uncertainties in both concentration means and load estimates when assessing the state of a water body or planning mitigation measures. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Intelligent electrical outlet for collective load control

    Science.gov (United States)

    Lentine, Anthony L.; Ford, Justin R.; Spires, Shannon V.; Goldsmith, Steven Y.

    2015-10-27

    Various technologies described herein pertain to an electrical outlet that autonomously manages loads in a microgrid. The electrical outlet can provide autonomous load control in response to variations in electrical power generation supply in the microgrid. The electrical outlet includes a receptacle, a sensor operably coupled to the receptacle, and an actuator configured to selectively actuate the receptacle. The sensor measures electrical parameters at the receptacle. Further, a processor autonomously controls the actuator based at least in part on the electrical parameters measured at the receptacle, electrical parameters from one or more disparate electrical outlets in the microgrid, and a supply of generated electric power in the microgrid at a given time.

  12. Estimated suspended-sediment loads and yields in the French and Brandywine Creek Basins, Chester County, Pennsylvania, water years 2008-09

    Science.gov (United States)

    Sloto, Ronald A.; Olson, Leif E.

    2011-01-01

    Turbidity and suspended-sediment concentration data were collected by the U.S. Geological Survey (USGS) at four stream stations--French Creek near Phoenixville, West Branch Brandywine Creek near Honey Brook, West Branch Brandywine Creek at Modena, and East Branch Brandywine Creek below Downingtown--in Chester County, Pa. Sedimentation and siltation is the leading cause of stream impairment in Chester County, and these data are critical for quantifying sediment transport. This study was conducted by the USGS in cooperation with the Chester County Water Resources Authority and the Chester County Health Department. Data from optical turbidity sensors deployed at the four stations were recorded at 15- or 30-minute intervals by a data logger and uploaded every 1 to 4 hours to the USGS database. Most of the suspended-sediment samples were collected using automated samplers. The use of optical sensors to continuously monitor turbidity provided an accurate estimate of sediment fluctuations without the collection and analysis costs associated with intensive sampling during storms. Turbidity was used as a surrogate for suspended-sediment concentration (SSC), which is a measure of sedimentation and siltation. Regression models were developed between SSC and turbidity for each of the monitoring stations using SSC data collected from the automated samplers and turbidity data collected at each station. Instantaneous suspended-sediment loads (SSL) were computed from time-series turbidity and discharge data for the 2008 and 2009 water years using the regression equations. The instantaneous computations of SSL were summed to provide daily, storm, and water year annual loads. The annual SSL contributed from each basin was divided by the upstream drainage area to estimate the annual sediment yield. For all four basins, storms provided more than 96 percent of the annual SSL. In each basin, four storms generally provided over half the annual SSL each water year. Stormflows with the

  13. Streambank alluvial unit contributions to suspended sediment and total phosphorus loads, Walnut Creek, Iowa, USA

    Science.gov (United States)

    Streambank erosion may represent a significant source of sediment and P to overall watershed loads, however, watershed-scale quantification of contributions are rare. In addition, streambanks are often comprised of highly-variable stratigraphic source materials (e.g., alluvial deposits), which may d...

  14. 40 CFR Appendix G to Part 50 - Reference Method for the Determination of Lead in Suspended Particulate Matter Collected From...

    Science.gov (United States)

    2010-07-01

    ... the sample as follows: 7.2.1.5.1 Rinse watch glass and sides of beaker with D.I. water. 7.2.1.5.2.... 1.1 Ambient air suspended particulate matter is collected on a glass-fiber filter for 24 hours using... lead content of the sample is analyzed by atomic absorption spectrometry using an air-acetylene flame...

  15. Assessing the impact of landuse change, climate change and reservoirs on suspended sediment load in Da river (China-Vietnam)

    Science.gov (United States)

    Van Thinh, Le; Soncini, Andrea; Bocchiola, Daniele; Ranzi, Roberto; Rulli, Maria Cristina

    2016-04-01

    Sediment issues have critical implications for aquatic ecology, agriculture, water supply and river navigation. Recently, with the construction and operation of several reservoirs in Da river basin (China-Vietnam), such as Hoa Binh, Lai Chau, Son La and so on, this issue has risen high interest and concern. Reservoirs have been built to meet several important needs, including increasing energy, irrigation, and drinking water demand. However, the decision maker should pay attention to the effects on sediment load, namely trapping of sediments, reduction of sediment concentration downstream reservoirs, increasing riverbank erosion, and localized erosion nearby hydraulic structures. In addition, land use changes, and climate changes are also to be considered as causing effect on sediment erosion and transport. The aim of this work is to evaluate the effects of separate factors (reservoirs, land use change, and climate change) on sediment load in the Da river basin. To this purpose, an updated and enhanced version of the soil erosion and transport model at the catchment scale, namely DIMOSHONG_RUSLE is applied to the Da river basin. More than 50 years of monthly precipitation, runoff and suspended sediment load data are processed. Two historical (1983, 2000) land use maps were generated based on statistic data of the government. The effect of land use change, and reservoirs is assessed on the basis of trends observed in the last decades. To develop the DIMOSHONG_RUSLE model in the period 1961-1985 with land use 1983 (before Hoa Binh reservoir was constructed completely) an updated version of the parameters of the RUSLE equation is determined according to the space variability on the soil types base on experimental data. Then, using chosen optimized parameter of RUSLE, suspended sediment load for the period 1986-2005 (with the Hoa Binh reservoir built and in operation) corresponding with land use in 2000 are calculated. The results are in good agreement with observed

  16. Suspended sediment load below open-cast mines for ungauged river basin

    Science.gov (United States)

    Kuksina, L.

    2011-12-01

    Placer mines are located in river valleys along river benches or river ancient channels. Frequently the existing mining sites are characterized by low contribution of the environmental technologies. Therefore open-pit mining alters stream hydrology and sediment processes and enhances sediment transport. The most serious environmental consequences of the sediment yield increase occur in the rivers populated by salmon fish community because salmon species prefer clean water with low turbidity. For instance, placer mining located in Kamchatka peninsula (Far East of Russia) which is regarded to be the last global gene pool of wild salmon Oncorhynchus threatens rivers ecosystems significantly. Impact assessment is limited by the hydrological observations scarcity. Gauging network is rare and in many cases whole basins up to 200 km length miss any hydrological data. The main purpose of the work is elaboration of methods for sediment yield estimation in rivers under mining impact and implementation of corresponding calculations. Subjects of the study are rivers of the Vivenka river basin where open-cast platinum mine is situated. It's one of the largest platinum mines in Russian Federation and in the world. This mine is the most well-studied in Kamchatka (research covers a period from 2003 to 2011). Empirical - analytical model of suspended sediment yield estimation was elaborated for rivers draining mine's territories. Sediment delivery at the open-cast mine happens due to the following sediment processes: - erosion in the channel diversions; - soil erosion on the exposed hillsides; - effluent from settling ponds; - mine waste water inflow; - accident mine waste water escape into rivers. Sediment washout caused by erosion was estimated by repeated measurements of the channel profiles in 2003, 2006 and 2008. Estimation of horizontal deformation rates was carried out on the basis of erosion dependence on water discharge rates, slopes and composition of sediments. Soil

  17. Application of dimensionless sediment rating curves to predict suspended-sediment concentrations, bedload, and annual sediment loads for rivers in Minnesota

    Science.gov (United States)

    Ellison, Christopher A.; Groten, Joel T.; Lorenz, David L.; Koller, Karl S.

    2016-10-27

    Consistent and reliable sediment data are needed by Federal, State, and local government agencies responsible for monitoring water quality, planning river restoration, quantifying sediment budgets, and evaluating the effectiveness of sediment reduction strategies. Heightened concerns about excessive sediment in rivers and the challenge to reduce costs and eliminate data gaps has guided Federal and State interests in pursuing alternative methods for measuring suspended and bedload sediment. Simple and dependable data collection and estimation techniques are needed to generate hydraulic and water-quality information for areas where data are unavailable or difficult to collect.The U.S. Geological Survey, in cooperation with the Minnesota Pollution Control Agency and the Minnesota Department of Natural Resources, completed a study to evaluate the use of dimensionless sediment rating curves (DSRCs) to accurately predict suspended-sediment concentrations (SSCs), bedload, and annual sediment loads for selected rivers and streams in Minnesota based on data collected during 2007 through 2013. This study included the application of DSRC models developed for a small group of streams located in the San Juan River Basin near Pagosa Springs in southwestern Colorado to rivers in Minnesota. Regionally based DSRC models for Minnesota also were developed and compared to DSRC models from Pagosa Springs, Colorado, to evaluate which model provided more accurate predictions of SSCs and bedload in Minnesota.Multiple measures of goodness-of-fit were developed to assess the effectiveness of DSRC models in predicting SSC and bedload for rivers in Minnesota. More than 600 dimensionless ratio values of SSC, bedload, and streamflow were evaluated and delineated according to Pfankuch stream stability categories of “good/fair” and “poor” to develop four Minnesota-based DSRC models. The basis for Pagosa Springs and Minnesota DSRC model effectiveness was founded on measures of goodness

  18. Suspended solids and total phosphorus loads and their spatial differences in a lake-rich river basin as determined by automatic monitoring network.

    Science.gov (United States)

    Koskiaho, Jari; Tattari, Sirkka; Röman, Elina

    2015-04-01

    Turbidity datasets recorded by sensors during 2009-2012 were collected in five observation sites in the 2046-km2 Karjaanjoki River Basin in southern Finland. From these and water sample-based data, total phosphorus (TP) and total suspended solids (TSS) fluxes were determined. Based on calculations made with combined sensor- and water sample-based dataset, the annual loading from the Karjaanjoki Basin in 2009-2012 varied between 11,300 and 23,900[corrected] kg of TP and 3300-8400 t of TSS. As compared with two other river basins discharging into the Baltic Sea in southern Finland, the TP loading from Karjaanjoki was low because the summed retention in the two major lakes Hiidenvesi and Lohjanjärvi was high: 48 and 49% of the TSS and TP loadings generated in their upstream catchments, respectively. Depending on how water sampling took place in relation to peak flow events, differences of annual fluxes as determined by "water samples only" vs. "sensors and water samples" data varied between -22 and 26 for TP and -31 and 39% for TSS. This study proved automatic monitoring being useful when spatial differences and lake retention of riverine fluxes are explored. Moreover, the loading estimates calculated on the base of well-functioning and well-maintained automatic monitoring system, supported with water sampling during periods when devices were off, are undoubtedly more accurate than those based on manual grab water sampling only. The findings of this study were in line with, and well contribute to, earlier Finnish and international research on automatic water quality monitoring.

  19. Trends in Streamflow and Nutrient and Suspended-Sediment Concentrations and Loads in the Upper Mississippi, Ohio, Red, and Great Lakes River Basins, 1975-2004

    Science.gov (United States)

    Lorenz, David L.; Robertson, Dale M.; Hall, David W.; Saad, David A.

    2009-01-01

    Many actions have been taken to reduce nutrient and suspended-sediment concentrations and the amount of nutrients and sediment transported in streams as a result of the Clean Water Act and subsequent regulations. This report assesses how nutrient and suspended-sediment concentrations and loads in selected streams have changed during recent years to determine if these actions have been successful. Flow-adjusted and overall trends in concentrations and trends in loads from 1993 to 2004 were computed for total nitrogen, dissolved ammonia, total organic nitrogen plus ammonia, dissolved nitrite plus nitrate, total phosphorus, dissolved phosphorus, total suspended material (total suspended solids or suspended sediment), and total suspended sediment for 49 sites in the Upper Mississippi, Ohio, Red, and Great Lakes Basins. Changes in total nitrogen, total phosphorus, and total suspended-material loads were examined from 1975 to 2003 at six sites to provide a longer term context for the data examined from 1993 to 2004. Flow-adjusted trends in total nitrogen concentrations at 19 of 24 sites showed tendency toward increasing concentrations, and overall trends in total nitrogen concentrations at 16 of the 24 sites showed a general tendency toward increasing concentrations. The trends in these flow-adjusted total nitrogen concentrations are related to the changes in fertilizer nitrogen applications. Flow-adjusted trends in dissolved ammonia concentrations from 1993 to 2004 showed a widespread tendency toward decreasing concentrations. The widespread, downward trends in dissolved ammonia concentrations indicate that some of the ammonia reduction goals of the Clean Water Act are being met. Flow-adjusted and overall trends in total organic plus ammonia nitrogen concentrations from 1993 to 2004 did not show a distinct spatial pattern. Flow-adjusted and overall trends in dissolved nitrite plus nitrate concentrations from 1993 to 2004 also did not show a distinct spatial pattern

  20. Comparative study of predatory responses in blue mussels (Mytilus edulis L.) produced in suspended long line cultures or collected from natural bottom mussel beds

    DEFF Research Database (Denmark)

    Christensen, Helle Torp; Dolmer, Per; Petersen, Jens Kjerulf

    2011-01-01

    is the availability of seed mussels collected with minimum impact on the benthic ecosystem. To examine whether mussels collected in suspended cultures can be used for bottom culture production and as tool in habitat improvement, the differences in predatory defence responses between suspended and bottom mussels...... exposed to the predatory shore crab (Carcinus maenas L.) were tested in laboratory experiments and in the field. Predatory defence responses (byssal attachment and aggregation) and morphological traits were tested in laboratory, while growth and mortality were examined in field experiments. Suspended...

  1. Reconstructing the suspended sediment load of the Yellow River since 1470 CE using the Drought and Flood Index

    Science.gov (United States)

    Xu, Jiongxin

    2017-12-01

    The Yellow River of China is well known around the world for its large sediment yield and suspended sediment load (SSL). To better understand the cause of SSL variability, we need long-term perspectives that go back 100-1000 yr. However, few long-term reconstructions have been published, especially with high temporal resolution. In this study, we show that the Drought and Flood Index (IDF) based on historical document analysis can be used as a proxy to reconstruct the SSL, the high-flow season (June-October) stream flow, and the annual precipitation of the middle Yellow River from 1470-1919. The calibration equation explains 57.6% of the variance in the SSL produced from the drainage area between the Hekouzhen and Longmen stations on the Yellow River. Variation in the IDF reflects the variation in the summer monsoon in China that causes the variation in water vapor transport, precipitation, and soil erosion. These links explain the mechanism of reconstructing the SSL based on the IDF. The reconstructed 450 yr series shows that the SSL responds sensitively to El Niño events. The reconstructed SSL may be used as a baseline to assess the effects of human activity on the SSL for the period after 1970, and the reduction in SSL for the period 1971-2013 was estimated as 4.09 × 108 t/yr, accounting for 48.9% of the annual SSL induced by only climate.

  2. Estimating of suspended sediment loads of rivers in the Seine downstream basin and coastal rivers in Southeastern Channel

    Science.gov (United States)

    Landemaine, Valentin; Cerdan, Olivier; Laignel, Benoit; Fournier, Matthieu; Copard, Yoann

    2014-05-01

    Sediment exports in rivers constitute the essential of materials transfer from the land surface to the ocean and contribute significantly to the transfer of nutrients, pesticides, heavy metals which can affect water quality. Such problems of water pollution are particularly present at the Norman loess plateaus because soil erosion is a frequent phenomena and mudslides are common. In this context, the quantification of sediment load, as well as the short and long term variability analysis are a key component for any sustainable management project of water resources. The quantification of sediment fluxes is based on turbidity, suspended sediment concentrations (SSC) and discharge measurements. These measurements must be made with sufficient high frequency for integrating temporal variability of SSC and flows. However, the cost of a high frequency monitoring limits their use at large scale. In France, discharges are monitored using daily frequency (Banque Hydro), while SSC are measured in monthly or bimonthly frequency under the national water quality survey system (RNB). With these low frequency measurements, an algorithm must be used to reconstruct SSC temporal variability and to estimate a sediment flux. Many estimation algorithms have been developed in recent decades, from the simplest to the most elaborate, but no consensus has been reached on the use of a particular algorithm because of the complexity of SSC-discharge relationship. In this study, the analysis focuses on eight Channel coastal watersheds and nine Seine watersheds in the downstream part. We have a several years of high-frequency measurements on nine watersheds with highly variable area (10 km² to 10,000 km²) and low-frequency measurements for all watersheds. From these data, we compared the statistical performance of eleven algorithms to estimate sediment fluxes conventionally used in the literature. These algorithms are: averaging estimator, ratio estimator, linear interpolation, rating curve

  3. Assessment of selected contaminants in streambed- and suspended-sediment samples collected in Bexar County, Texas, 2007-09

    Science.gov (United States)

    Wilson, Jennifer T.

    2011-01-01

    Elevated concentrations of sediment-associated contaminants are typically associated with urban areas such as San Antonio, Texas, in Bexar County, the seventh most populous city in the United States. This report describes an assessment of selected sediment-associated contaminants in samples collected in Bexar County from sites on the following streams: Medio Creek, Medina River, Elm Creek, Martinez Creek, Chupaderas Creek, Leon Creek, Salado Creek, and San Antonio River. During 2007-09, the U.S. Geological Survey periodically collected surficial streambed-sediment samples during base flow and suspended-sediment (large-volume suspended-sediment) samples from selected streams during stormwater runoff. All sediment samples were analyzed for major and trace elements and for organic compounds including halogenated organic compounds and polycyclic aromatic hydrocarbons (PAHs). Selected contaminants in streambed and suspended sediments in watersheds of the eight major streams in Bexar County were assessed by using a variety of methods—observations of occurrence and distribution, comparison to sediment-quality guidelines and data from previous studies, statistical analyses, and source indicators. Trace elements concentrations were low compared to the consensus-based sediment-quality guidelines threshold effect concentration (TEC) and probable effect concentration (PEC). Trace element concentrations were greater than the TEC in 28 percent of the samples and greater than the PEC in 1.5 percent of the samples. Chromium concentrations exceeded sediment-quality guidelines more frequently than concentrations of any other constituents analyzed in this study (greater than the TEC in 69 percent of samples and greater than the PEC in 8 percent of samples). Mean trace element concentrations generally are lower in Bexar County samples compared to concentrations in samples collected during previous studies in the Austin and Fort Worth, Texas, areas, but considering the relatively

  4. Hafnium and neodymium isotopes and REY distribution in the truly dissolved, nanoparticulate/colloidal and suspended loads of rivers in the Amazon Basin, Brazil

    Science.gov (United States)

    Merschel, Gila; Bau, Michael; Schmidt, Katja; Münker, Carsten; Dantas, Elton L.

    2017-09-01

    Radiogenic isotopes in river sediments and river waters have been widely used in provenance studies, as these samples naturally integrate the geology/chemistry of the entire catchment. While the Hf and Nd isotope systems are coupled during igneous processes, they are decoupled during supergene processes at the Earth's surface, which is reflected by the isotope composition of riverine sediments. We present the first data for both Hf and Nd isotope compositions of the dissolved (0.2 μm-filtrates rich in nanoparticles and colloids, NPCs) and the truly dissolved (1 kDa-ultrafiltrates) load of rivers. Hafnium and Nd isotope compositions and concentrations of the Rare Earths and Yttrium (REY) and Hf were determined for suspended particles (>0.2 μm) as well as for the dissolved and the truly dissolved load of the Rio Solimões, the Amazon's largest tributary draining the Andes, and of the Rio Negro, an organic NPC- and particle-rich river draining the rainforest of northern Amazonia. We also analyzed the Nd isotope compositions of suspended sediments and 0.2 μm-filtered water samples from the Amazon River and its tributaries Rio Tapajos, Rio Xingu and Rio Jari. Our novel results clearly show that the decoupling of the Hf and Nd isotope systems is related to incongruent weathering processes on the continent, as this decoupling can already be observed in the different Hf and Nd pools, i.e. in the particulate, the NPC-dominated dissolved and the truly dissolved load of rivers. In the Rio Negro and Rio Solimões, a strong particle size-dependent difference in Hf isotope composition is observed. Values of εHf become more radiogenic as filter poresize decreases, which can be related to the density- and size-dependent distribution of Hf-rich minerals, e.g. zircons, and their absence from the truly dissolved pool. In contrast, the Nd isotope composition of Amazonian river waters reflects that of their catchment geology. Tributaries draining the Precambrian Brazilian and

  5. Collectively loading an application in a parallel computer

    Science.gov (United States)

    Aho, Michael E.; Attinella, John E.; Gooding, Thomas M.; Miller, Samuel J.; Mundy, Michael B.

    2016-01-05

    Collectively loading an application in a parallel computer, the parallel computer comprising a plurality of compute nodes, including: identifying, by a parallel computer control system, a subset of compute nodes in the parallel computer to execute a job; selecting, by the parallel computer control system, one of the subset of compute nodes in the parallel computer as a job leader compute node; retrieving, by the job leader compute node from computer memory, an application for executing the job; and broadcasting, by the job leader to the subset of compute nodes in the parallel computer, the application for executing the job.

  6. Factors influencing storm-generated suspended-sediment concentrations and loads in four basins of contrasting land use, humid-tropical Puerto Rico

    Science.gov (United States)

    Gellis, Allen C.

    2013-01-01

    The significant characteristics controlling the variability in storm-generated suspended-sediment loads and concentrations were analyzed for four basins of differing land use (forest, pasture, cropland, and urbanizing) in humid-tropical Puerto Rico. Statistical analysis involved stepwise regression on factor scores. The explanatory variables were attributes of flow, hydrograph peaks, and rainfall, categorized into 5 flow periods: (1) the current storm hydrograph, (2) the flow and rainfall since the previous storm event, (3) the previous storm event, (4) 2nd previous storm event, and (5) the 3rd previous storm event. The response variables (storm generated sediment loads and concentrations) were analyzed for three portions of the storm hydrograph: (1) the entire storm, (2) the rising limb, and (3) the recessional limb. Hysteresis differences in sediment concentration between the rising and falling limb were also analyzed using these explanatory variables.

  7. Measurement differences between turbidity instruments, and their implications for suspended sediment concentration and load calculations: A sensor inter-comparison study.

    Science.gov (United States)

    Rymszewicz, A; O'Sullivan, J J; Bruen, M; Turner, J N; Lawler, D M; Conroy, E; Kelly-Quinn, M

    2017-09-01

    The use of turbidity for indicating environmentally detrimental levels of suspended and colloidal matter in freshwater systems, and for defining acceptable water quality standards in national and European drinking water regulations, is well established. Turbidity is therefore frequently adopted as a surrogate for suspended sediment concentrations (SSC), or as a relative and objective measure of water clarity in monitoring programmes. Through systematic, controlled experimentation, we tested the response of 12 commercially available turbidity sensors, of various designs, to gauge their measurement consistency when benchmarked against pre-prepared sediment suspensions of known SSC. Results showed that despite calibration to a Formazin standard, sensor responses to identical SSC solutions (in the range of 20-1000 mg L(-1)) varied considerably. For a given SSC, up to five-fold differences in recorded turbidity were recorded across the tested instruments. Furthermore, inconsistent measurements were identified across instruments, regardless of whether they operated using backscatter or side-scatter optical principles. While the findings may have implications for compliance with turbidity-based water quality standards, they are less likely to be an issue when turbidity is being used as a surrogate for SSC, provided that instrument use remains constant and that instrument drift is not an issue. In this study, a field comparison of a subset of four study sensors showed that despite very different absolute turbidity readings for a given SSC, well correlated and reliable turbidity - SSC ratings were established (as evidenced by r(2) coefficients from 0.92 to 0.98). This led to reasonably consistent suspended sediment load estimates of between 64.7 and 70.8 tonnes for a rainfall event analysed. This study highlights the potential for issues to arise when interpreting water turbidity datasets that are often assumed to be comparable, in that measurement inconsistency of the

  8. Sediment transport dynamics in the Central Himalaya: assessing during monsoon the erosion processes signature in the daily suspended load of the Narayani river

    Science.gov (United States)

    Morin, Guillaume; Lavé, Jérôme; Lanord, Christian France; Prassad Gajurel, Ananta

    2017-04-01

    The evolution of mountainous landscapes is the result of competition between tectonic and erosional processes. In response to the creation of topography by tectonics, fluvial, glacial, and hillslope denudation processes erode topography, leading to rock exhumation and sediment redistribution. When trying to better document the links between climate, tectonic, or lithologic controls in mountain range evolution, a detailed understanding of the influence of each erosion process in a given environment is fundamental. At the scale of a whole mountain range, a systematic survey and monitoring of all the geomorphologic processes at work can rapidly become difficult. An alternative approach can be provided by studying the characteristics and temporal evolution of the sediments exported out of the range. In central Himalaya, the Narayani watershed presents contrasted lithologic, geochemical or isotopic signatures of the outcropping rocks as well as of the erosional processes: this particular setting allows conducting such type of approach by partly untangling the myopic vision of the spatial integration at the watershed scale. Based on the acquisition and analysis of a new dataset on the daily suspended load concentration and geochemical characteristics at the mountain outlet of one of the largest Himalayan rivers (drainage area = 30000 km2) bring several important results on Himalayan erosion, and on climatic and process controls. 1. Based on discrete depth sampling and on daily surface sampling of suspended load associated to flow characterization through ADCP measurements, we were first able to integrate sediment flux across a river cross-section and over time. We estimate for 2010 year an equivalent erosion rate of 1.8 +0.35/-0.2 mm/yr, and over the last 15 years, using past sediment load records from the DHM of Nepal, an equivalent erosion rate of 1.6 +0.3/-0.2 mm/yr. These rates are also in close agreement with the longer term ( 500 yrs) denudation rates of 1.7 mm

  9. Pre-aged soil organic carbon as a major component of the Yellow River suspended load: Regional significance and global relevance

    Science.gov (United States)

    Tao, Shuqin; Eglinton, Timothy I.; Montluçon, Daniel B.; McIntyre, Cameron; Zhao, Meixun

    2015-03-01

    Large rivers connect the continents and the oceans, and corresponding material fluxes have a global impact on marine biogeochemistry. The Yellow River transports vast quantities of suspended sediments to the ocean, yet the nature of the particulate organic carbon (POC) carried by this system is not well known. The focus of this study is to characterize the sources, composition and age of suspended POC collected near the terminus of this river system, focusing on the abundance and carbon isotopic composition (13C and 14C) of specific biomarkers. The concentrations of vascular plant wax lipids (long-chain (≥C24) n-alkanes, n-fatty acids) and POC co-varied with total suspended solid (TSS) concentrations, indicating that both were controlled by the overall terrestrial sediment flux. POC exhibited relatively uniform δ13C values (-23.8 to -24.2‰), and old radiocarbon ages (4000-4640 yr). However, different biomarkers exhibited a wide range of 14C ages. Short-chain (C16, C18) fatty acid 14C ages were variable but generally the youngest organic components (from 502 yr to modern), suggesting they reflect recently biosynthesized material. Lignin phenol 14C ages were also variable and relatively young (1070 yr to modern), suggesting rapid export of carbon from terrestrial primary production. In contrast, long-chain plant wax lipids display relatively uniform and significantly older 14C ages (1500-1800 yr), likely reflecting inputs of pre-aged, mineral-associated soil OC from the Yellow River drainage basin. Even-carbon-numbered n-alkanes yielded the oldest 14C ages (up to 26 000 yr), revealing the presence of fossil (petrogenic) OC. Two isotopic mass balance approaches were explored to quantitively apportion different OC sources in Yellow River suspended sediments. Results indicate that the dominant component of POC (53-57%) is substantially pre-aged (1510-1770 yr), and likely sourced from the extensive loess-paleosol deposits outcropping within the drainage basin. Of

  10. Estimates of suspended sediment entering San Francisco Bay from the Sacramento and San Joaquin Delta, San Francisco Bay, California

    Science.gov (United States)

    McKee, L.J.; Ganju, N.K.; Schoellhamer, D.H.

    2006-01-01

    This study demonstrates the use of suspended-sediment concentration (SSC) data collected at Mallard Island as a means of determining suspended-sediment load entering San Francisco Bay from the Sacramento and San Joaquin River watersheds. Optical backscatter (OBS) data were collected every 15 min during water years (WYs) 1995-2003 and converted to SSC. Daily fluvial advective sediment load was estimated by combining estimated Delta outflow with daily averaged SSC. On days when no data were available, SSC was estimated using linear interpolation. A model was developed to estimate the landward dispersive load using velocity and SSC data collected during WYs 1994 and 1996. The advective and dispersive loads were summed to estimate the total load. Annual suspended-sediment load at Mallard Island averaged 1.2??0.4 Mt (million metric tonnes). Given that the average water discharge for the 1995-2003 period was greater than the long -term average discharge, it seems likely that the average suspended-sediment load may be less than 1.2??0.4 Mt. Average landward dispersive load was 0.24 Mt/yr, 20% of the total. On average during the wet season, 88% of the annual suspended-sediment load was discharged through the Delta and 43% occurred during the wettest 30-day period. The January 1997 flood transported 1.2 Mt of suspended sediment or about 11% of the total 9-year load (10.9 Mt). Previous estimates of sediment load at Mallard Island are about a factor of 3 greater because they lacked data downstream from riverine gages and sediment load has decreased. Decreasing suspended-sediment loads may increase erosion in the Bay, help to cause remobilization of buried contaminants, and reduce the supply of sediment for restoration projects. ?? 2005 Elsevier B.V. All rights reserved.

  11. Occurrence and seasonal loads of pesticides in surface water and suspended particulate matter from a wetland of worldwide interest--the Ria Formosa Lagoon, Portugal.

    Science.gov (United States)

    Cruzeiro, Catarina; Pardal, Miguel Ângelo; Rocha, Eduardo; Rocha, Maria João

    2015-11-01

    Two novel methods were developed to extract and quantify 56 pesticides in surface waters, considering their content in both dissolved aqueous phase (DAP) and suspended particulate matter (SPM) fractions. These procedures were applied to coastal samples taken seasonally during 2012-2013, from three strategic sampling sites along the Ria Formosa Lagoon (south of Portugal). Briefly, 500 mL of water samples were filtrated, separating both fractions. The DAP fraction was extracted and pre-concentrated by solid-phase extraction (SPE), while the SPM was extracted using ultrasonic extraction technique (USE). Both fractions were then analyzed, and the pesticides were quantified and identified, within 35 min, by gas chromatography (GC) coupled to mass spectrometry (GC-MS and GC-MS/MS), respectively. The extraction of pesticides from the SPM fraction showed average recoveries of 102%, detection limits below 2.2 ng/L, and quantification limits ranging from 0.3 to 6.6 ng/L. Considering the real water samples, 73% of the selected pesticides were quantified in both DAP and SPM fractions (ΣDAP+SPM 2.3 μg/L) and their maximum levels were measured in autumn and winter. By category, the global loads of fungicides, herbicides, and insecticides were ≈407, ≈323, and ≈1.6 μg/L, respectively. Thirty-one percent of the quantified pesticides exceeded the European directives levels (2008/105/EC and 98/83/EC). From the total loads, the SPM fraction contribution was 32%, showing the importance of measuring pesticides in that fraction. The water physicochemical parameters revealed that the total nitrogen amounts were very high relatively to the legal required values, mainly close to the city of Faro (2.6 mg/L). In light of the above, measures are in need to meet European directives and protect both fauna and humans that use this area for leisure.

  12. Suspended microfluidics

    OpenAIRE

    Casavant, Benjamin P.; Berthier, Erwin; Theberge, Ashleigh B.; Jean BERTHIER; Montanez-Sauri, Sara I.; Bischel, Lauren L.; Brakke, Kenneth; Hedman, Curtis J.; Bushman, Wade; Keller, Nancy P.; Beebe, David J.

    2013-01-01

    Although the field of microfluidics has made significant progress in bringing new tools to address biological questions, the accessibility and adoption of microfluidics within the life sciences are still limited. Open microfluidic systems have the potential to lower the barriers to adoption, but the absence of robust design rules has hindered their use. Here, we present an open microfluidic platform, suspended microfluidics, that uses surface tension to fill and maintain a fluid in microscale...

  13. A New Model to Predict the Total Suspended Sediment Load from a River to the Ocean Based on an End Member Example from the Lowermost Huanghe (Yellow River), China

    Science.gov (United States)

    Ma, H.; Nittrouer, J. A.; Naito, K.; Parker, G.

    2016-12-01

    The total suspended sediment load in a river estuary links continentally derived material to marine deposits, and therefore it is important to quantify the physical conditions impacting movement of sediment in an estuary. Depending on its source, suspended riverine sediment comprises proportions of bed material load and wash load whereby bed material sediment originates from the channel bed. Typically after propagation of flow over the channel bed, bed material load at the estuary is always at its transport capacity, and its flux can be predicted based on the local physical conditions. On the contrary, wash load is usually below its transport capacity, because flux is set by upstream input. Therefore, physically-based methods for predicting wash load flux are limited, and instead wash load in rivers is determined by using empirical techniques, which must be constantly updated over time due to changing environmental conditions and anthropogenic pressures. Here, we hypothesize that for any river with a sufficiently high sediment concentration, wash load reaches transport capacity, as set by both hydrodynamic conditions and also constrained by the bed material load. To test this, a sediment transport database obtained from the lower Huanghe, China, is analyzed. We find that for this system, which is the most sediment concentrated river in the world, the bed material load reduces the transport capacity of wash load in the flow. By knowing bed material load, a competitive relationship between this sediment flux and wash load is produced, and used to reveal the remaining transport capacity available for wash load transport. This demonstrates the ability to have a physically based methodology for predicting wash load and, when combined with bed material load, the total fluvial sediment load discharged to the marine environment. However, the examination of applying condition of present methodology reveals that the methodology is generally suitable for rivers with bed

  14. Assessing the applicability of TMPA-3B42V7 precipitation dataset in wavelet-support vector machine approach for suspended sediment load prediction

    Science.gov (United States)

    Himanshu, Sushil Kumar; Pandey, Ashish; Yadav, Basant

    2017-07-01

    In the present study, the latest Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) research product 3B42V7 has been evaluated over gauge-based India Meteorological Department (IMD) gridded dataset employing statistical and contingency table methods for two South Indian watersheds. A comparative analysis of TMPA-3B42V7 with IMD gauge-based gridded dataset was carried out on daily, monthly, seasonal and yearly basis for 16 years (1998-2013). The study revealed that TMPA estimates performed reasonably well with the gauge-based gridded dataset, however, some significant biases were also observed. It has been observed that TMPA overestimates at very light rain, but underestimates at light, moderate, heavy and very heavy rainfall intensities. Further, the TMPA estimates was evaluated for prediction of daily suspended sediment load (SL) employing Support Vector Machine (SVM) with wavelet analysis (WASVM). Initially, 1-day ahead SL prediction was performed using best WASVM model. The results showed that 1-day predictions were very precise and shows a better agreement with the observed SL data. Later, the developed WASVM model was used for the prediction of SL for the higher leads period. The statistical analysis shows that the developed WASVM model could predict the target value successfully up to 6-days lead and found to be not suitable for higher lead specifically in the selected watersheds with similar hydro-climatic conditions like the ones selected in this study. Predictions results of WASVM model is superior to conventional SVM model and could be used as an effective forecasting tool for hydrological applications. The study suggest that the use of TMPA precipitation estimates can be a compensating approach after suitable bias correction and have potential for SL prediction in data-sparse regions.

  15. Tracing suspended sediment sources in the Upper Sangamon River Basin using fingerprinting techniques

    Science.gov (United States)

    Yu, M.; Rhoads, B. L.; Neal, C.; Anders, A. M.

    2014-12-01

    As the awareness of water pollution, eutrophication and other water related environmental concerns grows, the significance of sediment in the transport of nutrients and contaminants from agricultural areas to streams has received increasing attention. Both the physical and geochemical properties of suspended sediment are strongly controlled by sediment sources. Thus, tracing sources of suspended sediment in watersheds is important for the design of management practices to reduce sediment loads and contributions of sediment-adsorbed nutrients from agricultural areas to streams. However, the contributions of different sediment sources to suspended sediment loads within intensively managed watersheds in the Midwest still remain insufficiently explored. This study aims to assess the provenance of suspended sediment and the relation between channel morphology and production of suspended sediment in the Upper Sangamon River Basin, Illinois. The 3,690-km2 Upper Sangamon River Basin is characterized by low-relief, agricultural lands dominated by row-crop agriculture. Sediment source samples were collected in the Saybrook and Wildcat Slough sub-watersheds from six potential sources: row-crop agriculture, forest, floodplains, river banks, pastures, and grasslands. Event-based suspended sediment samples were collected by in situ suspended sediment samplers and ISCO automatic pump samplers from the streams. A quantitative geochemical fingerprinting technique, combining statistically verified multicomponent signatures and an unmixing model, was employed to estimate the relative contributions of sediment from six potential sources to the suspended sediment loads. Our preliminary results indicate that the majority of suspended sediment is derived from channel banks and forest adjacent to meandering reaches in the downstream portions of the watersheds, while only minor amounts of suspended sediment are derived from upland areas adjacent to channelized rivers in the low

  16. A reassessment of the suspended sediment load in the Madeira River basin from the Andes of Peru and Bolivia to the Amazon River in Brazil, based on 10 years of data from the HYBAM monitoring programme

    Science.gov (United States)

    Vauchel, Philippe; Santini, William; Guyot, Jean Loup; Moquet, Jean Sébastien; Martinez, Jean Michel; Espinoza, Jhan Carlo; Baby, Patrice; Fuertes, Oscar; Noriega, Luis; Puita, Oscar; Sondag, Francis; Fraizy, Pascal; Armijos, Elisa; Cochonneau, Gérard; Timouk, Franck; de Oliveira, Eurides; Filizola, Naziano; Molina, Jorge; Ronchail, Josyane

    2017-10-01

    The Madeira River is the second largest tributary of the Amazon River. It contributes approximately 13% of the Amazon River flow and it may contribute up to 50% of its sediment discharge to the Atlantic Ocean. Until now, the suspended sediment load of the Madeira River was not well known and was estimated in a broad range from 240 to 715 Mt yr-1. Since 2002, the HYBAM international network developed a new monitoring programme specially designed to provide more reliable data than in previous intents. It is based on the continuous monitoring of a set of 11 gauging stations in the Madeira River watershed from the Andes piedmont to the confluence with the Amazon River, and discrete sampling of the suspended sediment concentration every 7 or 10 days. This paper presents the results of the suspended sediment data obtained in the Madeira drainage basin during 2002-2011. The Madeira River suspended sediment load is estimated at 430 Mt yr-1 near its confluence with the Amazon River. The average production of the Madeira River Andean catchment is estimated at 640 Mt yr-1 (±30%), the corresponding sediment yield for the Andes is estimated at 3000 t km-2 yr-1 (±30%), and the average denudation rate is estimated at 1.20 mm yr-1 (±30%). Contrary to previous results that had mentioned high sedimentation rates in the Beni River floodplain, we detected no measurable sedimentation process in this part of the basin. On the Mamoré River basin, we observed heavy sediment deposition of approximately 210 Mt yr-1 that seem to confirm previous studies. But while these studies mentioned heavy sedimentation in the floodplain, we showed that sediment deposition occurred mainly in the Andean piedmont and immediate foreland in rivers (Parapeti, Grande, Pirai, Yapacani, Chimoré, Chaparé, Secure, Maniqui) with discharges that are not sufficiently large to transport their sediment load downstream in the lowlands.

  17. Nutrient and suspended-sediment trends, loads, and yields and development of an indicator of streamwater quality at nontidal sites in the Chesapeake Bay watershed, 1985-2010

    Science.gov (United States)

    Langland, Michael; Blomquist, Joel; Moyer, Douglas; Hyer, Kenneth

    2012-01-01

    The U.S. Geological Survey (USGS) updates information on loads of, and trends in, nutrients and sediment annually to help the Chesapeake Bay Program (CBP) investigators assess progress toward improving water-quality conditions in the Chesapeake Bay and its watershed. CBP scientists and managers have worked since 1983 to improve water quality in the bay. In 2010, the U.S. Environmental Protection Agency (USEPA) established a Total Maximum Daily Load (TMDL) for the Chesapeake Bay. The TMDL specifies nutrient and sediment load allocations that need to be achieved in the watershed to improve dissolved oxygen, water-clarity, and chlorophyll conditions in the bay. The USEPA, USGS, and state and local jurisdictions in the watershed operate a CBP nontidal water-quality monitoring network and associated database that are used to update load and trend information to help assess progress toward reducing nutrient and sediment inputs to the bay. Data collected from the CBP nontidal network were used to estimate loads and trends for two time periods: a long-term period (1985-2010) at 31 "primary" sites (with storm sampling) and a 10-year period (2001-10) at 33 primary sites and 16 "secondary" sites (without storm sampling). In addition, loads at 64 primary sites were estimated for the period 2006 to 2010. Results indicate improving flow-adjusted trends for nitrogen and phosphorus for 1985 to 2010 at most of the sites in the network. For nitrogen, 21 of the 31 sites showed downward (improving) trends, whereas 2 sites showed upward (degrading) trends, and 8 sites showed no trends. The results for phosphorus were similar: 22 sites showed improving trends, 4 sites showed degrading trends, and 5 sites indicated no trends. For sediment, no trend was found at 40 percent of the sites, with 10 sites showing improving trends and 8 sites showing degrading trends. The USGS, working with CBP partners, developed a new water-quality indicator that combines the results of the 10-year trend

  18. Tracing suspended sediment sources in the Upper Sangamon River Basin using conservative and non-conservative tracers

    Science.gov (United States)

    Yu, M.; Rhoads, B. L.; Stumpf, A.

    2015-12-01

    As the awareness of water pollution, eutrophication and other water related environmental concerns grows, the significance of sediment in the transport of nutrients and contaminants from agricultural areas to streams has received increasing attention. Both the physical and geochemical properties of suspended sediment are strongly controlled by sediment sources. Thus, tracing sources of suspended sediment in watersheds is important for the design of management practices to reduce sediment loads and contributions of sediment-adsorbed nutrients from agricultural areas to streams. However, the contributions of different sediment sources to suspended sediment loads within intensively managed watersheds in the Midwest still remain insufficiently explored. This study aims to assess the provenance of suspended sediment and the relation between channel morphology and production of suspended sediment in the Upper Sangamon River Basin, Illinois, USA. The 3,690-km2 Upper Sangamon River Basin is characterized by low-relief, agricultural lands dominated by row-crop agriculture. Sediment source samples were collected in the Saybrook from five potential sources: farmland, forests, floodplains, river banks, and grasslands. Event-based and accumulated suspended sediment samples were collected by ISCO automatic pump samplers and in situ suspended sediment samplers and from the stream at watershed outlet. A quantitative geochemical fingerprinting technique, combining statistically verified multicomponent signatures and an un-mixing model, was employed to estimate the relative contributions of sediment from five potential sources to the suspended sediment loads. Organic matter content, trace elements, and radionuclides from soil samples were used as potential tracers. Our preliminary results indicate that the majority of suspended sediment is derived from floodplains in the downstream portions of the watersheds, while only minor amounts of suspended sediment are derived from upland

  19. Impact of collection method on assessment of semen HIV RNA viral load.

    Directory of Open Access Journals (Sweden)

    Brendan J W Osborne

    Full Text Available The blood HIV RNA viral load is the best-defined predictor of HIV transmission, in part due to ease of measurement and the correlation of blood and genital tract (semen or cervico-vaginal viral load, although recent studies found semen HIV RNA concentration to be a stronger predictor of HIV transmission. There is currently no standardized method for semen collection when measuring HIV RNA concentration. Therefore, we compared two collection techniques in order to study of the impact of antiretroviral therapy on the semen viral load.Semen was collected by masturbation from HIV-infected, therapy-naïve men who have sex with men (MSM either undiluted (Visit 1 or directly into transport medium (Visit 2. Seminal plasma was then isolated, and the HIV RNA concentration obtained with each collection technique was measured and corrected for dilution if necessary. Collection of semen directly into transport medium resulted in a median HIV RNA viral load that was 0.4 log10 higher than undiluted samples.The method of semen collection is an important consideration when quantifying the HIV RNA viral load in this compartment.

  20. 23 Elemental Composition of Suspended Particulate Matter ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    Elemental Composition of Suspended Particulate Matter Collected at Two Different. Heights above the Ground in A Sub-Urban Site in Kenya. Gitari W. M1, Kinyua A. M. 2, Kamau G. N3 and C. K. Gatebe C. K4. Abstract. Suspended particulate matter samples were collected in a sub-urban area in Nairobi over a 12 month ...

  1. Suspended sediment yield in Texas watersheds

    Science.gov (United States)

    Coonrod, Julia Ellen Allred

    The Texas Water Development Board collected suspended sediment samples across the state of Texas for approximately 60 years. Until this research, no comprehensive analysis of the data had been conducted. This study compiles the suspended sediment data along with corresponding streamflow and rainfall. GIS programs are developed which characterize watersheds corresponding to the sediment gauging stations. The watersheds are characterized according to topography, climate, soils, and land use. All of the data is combined to form several SAS data sets which can subsequently be analyzed using regression. Annual data for all of the stations across the state are classified temporally and spatially to determine trends in the sediment yield. In general, the suspended sediment load increases with increasing runoff but no correlation exists with rainfall. However, the annual average rainfall can be used to classify the watersheds according to climate, which improves the correlation between sediment load and runoff. The watersheds with no dams have higher sediment loads than watersheds with dams. Dams in the drier parts of Texas reduce the sediment load more than dams in the wetter part of the state. Sediment rating curves are developed separately for each basin in Texas. All but one of the curves fall into a band which varies by about two orders of magnitude. The study analyzes daily time series data for the Lavaca River near Edna station. USGS data are used to improve the sediment rating curve by the addition of physically related variables and interaction terms. The model can explain an additional 41% of the variability in sediment concentration compared to a simple bivariate regression of sediment load and flow. The TWDB daily data for the Lavaca River near Edna station are used to quantify temporal trends. There is a high correlation between sediment load and flowrate for the Lavaca River. The correlation can be improved by considering a flow-squared term and by

  2. Fatigue Durability Analysis of Collecting Rapping System in Electrostatic Precipitators under Impact Loading

    OpenAIRE

    Ali Akbar Lotfi Neyestanak; Saeed Adib Nazari; Ali Imam; Cyrus Aghanajafi

    2014-01-01

    Due to the importance of collecting rapping system in electrostatic precipitators (ESP) and controlling the relevant damage under impact loading, fatigue durability of this system is analyzed in the present study based on the numerical and experimental results considering fatigue damage growth and vibration acceleration in the collecting system because of the successive impact of rapping hammers. By microscopic examination of the fracture surface of rapping hammer, beach marks obviously show ...

  3. Fatigue Durability Analysis of Collecting Rapping System in Electrostatic Precipitators under Impact Loading

    Directory of Open Access Journals (Sweden)

    Ali Akbar Lotfi Neyestanak

    2014-01-01

    Full Text Available Due to the importance of collecting rapping system in electrostatic precipitators (ESP and controlling the relevant damage under impact loading, fatigue durability of this system is analyzed in the present study based on the numerical and experimental results considering fatigue damage growth and vibration acceleration in the collecting system because of the successive impact of rapping hammers. By microscopic examination of the fracture surface of rapping hammer, beach marks obviously show typical fatigue failure in the rapping hammer arm. In addition, the microscopic examination of the cross section of the collecting plates indicates the corrosion voids which cause crack and eventually fatigue failure. The finite element method is applied to determine both the stress and concentration positions of dynamic stress on the rapping system under impact loading. The paper results can be utilized in system optimization and new material selection for the system by evaluating rapping system durability.

  4. High concentration suspended sediment measurments using acontinuous fiber optic in-stream transmissometer

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Chris G.; Laycak, Danny T.; Hoppes, William; Tran,Nguyen T.; Shi, Frank G.

    2004-05-26

    Suspended sediment loads mobilized during high flow periods in rivers and streams are largely uncharacterized. In smaller and intermittent streams, a large storm may transport a majority of the annual sediment budget. Therefore monitoring techniques that can measure high suspended sediment concentrations at semi-continuous time intervals are needed. A Fiber optic In-stream Transmissometer (FIT) is presented for continuous measurement of high concentration suspended sediment in storm runoff. FIT performance and precision were demonstrated to be reasonably good for suspended sediment concentrations up to 10g/L. The FIT was compared to two commercially available turbidity devices and provided better precision and accuracy at both high and low concentrations. Both turbidity devices were unable to collect measurements at concentrations greater than 4 g/L. The FIT and turbidity measurements were sensitive to sediment particle size. Particle size dependence of transmittance and turbidity measurement poses the greatest problem for calibration to suspended sediment concentration. While the FIT was demonstrated to provide acceptable measurements of high suspended sediment concentrations, approaches to real-time suspended sediment detection need to address the particle size dependence in concentration measurements.

  5. SPORT: An Algorithm for Divisible Load Scheduling with Result Collection on Heterogeneous Systems

    Science.gov (United States)

    Ghatpande, Abhay; Nakazato, Hidenori; Beaumont, Olivier; Watanabe, Hiroshi

    Divisible Load Theory (DLT) is an established mathematical framework to study Divisible Load Scheduling (DLS). However, traditional DLT does not address the scheduling of results back to source (i. e., result collection), nor does it comprehensively deal with system heterogeneity. In this paper, the DLSRCHETS (DLS with Result Collection on HET-erogeneous Systems) problem is addressed. The few papers to date that have dealt with DLSRCHETS, proposed simplistic LIFO (Last In, First Out) and FIFO (First In, First Out) type of schedules as solutions to DLSRCHETS. In this paper, a new polynomial time heuristic algorithm, SPORT (System Parameters based Optimized Result Transfer), is proposed as a solution to the DLSRCHETS problem. With the help of simulations, it is proved that the performance of SPORT is significantly better than existing algorithms. The other major contributions of this paper include, for the first time ever, (a) the derivation of the condition to identify the presence of idle time in a FIFO schedule for two processors, (b) the identification of the limiting condition for the optimality of FIFO and LIFO schedules for two processors, and (c) the introduction of the concept of equivalent processor in DLS for heterogeneous systems with result collection.

  6. Effects of May through July 2015 storm events on suspended sediment loads, sediment trapping efficiency, and storage capacity of John Redmond Reservoir, east-central Kansas

    Science.gov (United States)

    Foster, Guy M.

    2016-06-20

    The Neosho River and its primary tributary, the Cottonwood River, are the main sources of inflow to John Redmond Reservoir in east-central Kansas. Storage loss in the reservoir resulting from sedimentation has been estimated to be 765 acre-feet per year for 1964–2014. The 1964–2014 sedimentation rate was almost 90 percent larger than the projected design sedimentation rate of 404 acre-feet per year, and resulted in a loss of about 40 percent of the original (1964) conservation (multi-purpose) pool storage capacity. To help maintain storage in the reservoir, the Kansas Water Office has implemented more than two dozen stream bank erosion control projects to reduce the annual sediment load entering the reservoir and initiated a dredging project to restore nearly 2,000 acre-feet of storage near the dam to provide additional water supply to downstream water users. Storm events during May through July 2015 caused large inflows of water and sediment into the reservoir. Initially, flood waters were held back in the reservoir in order to decrease downstream flooding in Oklahoma. Later, retained reservoir flood waters were released at high rates (up to 25,400 acre-feet per day, the maximum allowed for the reservoir) for extended periods.

  7. Chemical composition of sediments, suspended matter, river water and ground water of the Nile (Aswan-Sohag traverse).

    Science.gov (United States)

    Dekov, V M; Komy, Z; Araújo, F; Van Put, A; Van Grieken, R

    1997-08-18

    Sediment, suspended matter, river water and ground water samples were collected at twelve sites in the drainage valley of the Nile River, around Sohag (Central Egypt) and close to the Aswan High Dam. Elemental composition of the river water (27 elements), ground water (eight elements), suspended matter (12 elements) and sediments (12 elements) was studied. Aswan High Dam construction, agricultural and industrial human activities have led to dramatic changes in the Nile River chemistry. Nowadays, the Nile River has the highest dissolved salt content among the major African rivers. Dissolved transport is a major process for Ca, K, Sr, Zn, Cu, Ni and V. Manganese, Fe and Cr are mainly carried by suspended matter. The Nile suspended matter is exhausted in almost all elements studied (except for Mn) compared to the world average river suspended matter. Along the course of the river, the distribution of elements in the suspended matter and sediments is generally controlled by natural processes: the relative importance of elemental transport phases; and the oxidation, precipitation and sedimentation of mineral species through the varying physico-chemical conditions of the environment. Pollution input in the Nile particulate load is not major, as compared to the natural inputs. Eight genetic particle types describe the composition of the Nile suspended matter and sediments: (1) biogenous-aeolian (or silica); (2) terrigenous (Fe-aluminosilicate); (3) authigenic (calcium carbonate); (4) biogenous (apatite); (5) authigenous-terrigenous (Fe-oxyhydroxide-montmorillonite); (6) diagenetic (iron-sulfide); (7) terrigenous (titanium oxide); (8) authigenous (Mn-Fe-oxyhydroxide).

  8. Field data collection of miscellaneous electrical loads in Northern California: Initial results

    Energy Technology Data Exchange (ETDEWEB)

    Greenblatt, Jeffery B. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.; Pratt, Stacy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.; Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.; Claybaugh, Erin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.; Desroches, Louis-Benoit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.; Beraki, Bereket [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.; Nagaraju, Mythri [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.; Price, Sarah K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.; Young, Scott J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division. Energy Analysis and Environmental Impacts Dept.

    2013-02-25

    This report describes efforts to measure energy use of miscellaneous electrical loads (MELs) in 880 San Francisco Bay Area homes during the summer of 2012. Ten regions were selected for metering: Antioch, Berkeley, Fremont, Livermore, Marin County (San Rafael, Novato, Fairfax, and Mill Valley), Oakland/Emeryville, Pleasanton, Richmond, San Leandro, and Union City. The project focused on three major categories of devices: entertainment (game consoles, set-top boxes, televisions and video players), home office (computers, monitors and network equipment), and kitchen plug-loads (coffee/espresso makers, microwave ovens/toaster ovens/toasters, rice/slow cookers and wine chillers). These categories were important to meter because they either dominated the estimated overall energy use of MELs, are rapidly changing, or there are very little energy consumption data published. A total of 1,176 energy meters and 143 other sensors were deployed, and 90% of these meters and sensors were retrieved. After data cleaning, we obtained 711 valid device energy use measurements, which were used to estimate, for a number of device subcategories, the average time spent in high power, low power and “off” modes, the average energy use in each mode, and the average overall energy use. Consistent with observations made in previous studies, we find on average that information technology (IT) devices (home entertainment and home office equipment) consume more energy (15.0 and 13.0 W, respectively) than non-IT devices (kitchen plug-loads; 4.9 W). Opportunities for energy savings were identified in almost every device category, based on the time spent in various modes and/or the power levels consumed in those modes. Future reports will analyze the collected data in detail by device category and compare results to those obtained from prior studies.

  9. Suspended sediment concentration and particle size distribution ...

    Indian Academy of Sciences (India)

    face area, shape, minerals and source) and conse- quent interaction with heavy metal concentrations. (HMCs). Recent studies have shown a growing awareness of the wider environmental significance of the suspended sediment loads transported by rivers and streams. This includes the importance of fine grain sediment in ...

  10. Improving suspended sediment measurements by automatic samplers.

    Science.gov (United States)

    Gettel, Melissa; Gulliver, John S; Kayhanian, Masoud; DeGroot, Gregory; Brand, Joshua; Mohseni, Omid; Erickson, Andrew J

    2011-10-01

    Suspended solids either as total suspended solids (TSS) or suspended sediment concentration (SSC) is an integral particulate water quality parameter that is important in assessing particle-bound contaminants. At present, nearly all stormwater runoff quality monitoring is performed with automatic samplers in which the sampling intake is typically installed at the bottom of a storm sewer or channel. This method of sampling often results in a less accurate measurement of suspended sediment and associated pollutants due to the vertical variation in particle concentration caused by particle settling. In this study, the inaccuracies associated with sampling by conventional intakes for automatic samplers have been verified by testing with known suspended sediment concentrations and known particle sizes ranging from approximately 20 μm to 355 μm under various flow rates. Experimental results show that, for samples collected at a typical automatic sampler intake position, the ratio of sampled to feed suspended sediment concentration is up to 6600% without an intake strainer and up to 300% with a strainer. When the sampling intake is modified with multiple sampling tubes and fitted with a wing to provide lift (winged arm sampler intake), the accuracy of sampling improves substantially. With this modification, the differences between sampled and feed suspended sediment concentration were more consistent and the sampled to feed concentration ratio was accurate to within 10% for particle sizes up to 250 μm.

  11. Long-term continuous acoustical suspended-sediment measurements in rivers - Theory, application, bias, and error

    Science.gov (United States)

    Topping, David J.; Wright, Scott A.

    2016-05-04

    It is commonly recognized that suspended-sediment concentrations in rivers can change rapidly in time and independently of water discharge during important sediment‑transporting events (for example, during floods); thus, suspended-sediment measurements at closely spaced time intervals are necessary to characterize suspended‑sediment loads. Because the manual collection of sufficient numbers of suspended-sediment samples required to characterize this variability is often time and cost prohibitive, several “surrogate” techniques have been developed for in situ measurements of properties related to suspended-sediment characteristics (for example, turbidity, laser-diffraction, acoustics). Herein, we present a new physically based method for the simultaneous measurement of suspended-silt-and-clay concentration, suspended-sand concentration, and suspended‑sand median grain size in rivers, using multi‑frequency arrays of single-frequency side‑looking acoustic-Doppler profilers. The method is strongly grounded in the extensive scientific literature on the incoherent scattering of sound by random suspensions of small particles. In particular, the method takes advantage of theory that relates acoustic frequency, acoustic attenuation, acoustic backscatter, suspended-sediment concentration, and suspended-sediment grain-size distribution. We develop the theory and methods, and demonstrate the application of the method at six study sites on the Colorado River and Rio Grande, where large numbers of suspended-sediment samples have been collected concurrently with acoustic attenuation and backscatter measurements over many years. The method produces acoustical measurements of suspended-silt-and-clay and suspended-sand concentration (in units of mg/L), and acoustical measurements of suspended-sand median grain size (in units of mm) that are generally in good to excellent agreement with concurrent physical measurements of these quantities in the river cross sections at

  12. Prediction of suspended-sediment concentrations at selected sites in the Fountain Creek watershed, Colorado, 2008-09

    Science.gov (United States)

    Stogner, Sr., Robert W.; Nelson, Jonathan M.; McDonald, Richard R.; Kinzel, Paul J.; Mau, David P.

    2013-01-01

    In 2008, the U.S. Geological Survey (USGS), in cooperation with Pikes Peak Area Council of Governments, Colorado Water Conservation Board, Colorado Springs City Engineering, and the Lower Arkansas Valley Water Conservancy District, began a small-scale pilot study to evaluate the effectiveness of the use of a computational model of streamflow and suspended-sediment transport for predicting suspended-sediment concentrations and loads in the Fountain Creek watershed in Colorado. Increased erosion and sedimentation damage have been identified by the Fountain Creek Watershed Plan as key problems within the watershed. A recommendation in the Fountain Creek Watershed plan for management of the basin is to establish measurable criteria to determine if progress in reducing erosion and sedimentation damage is being made. The major objective of this study was to test a computational method to predict local suspended-sediment loads at two sites with different geomorphic characteristics in order to evaluate the feasibility of using such an approach to predict local suspended-sediment loads throughout the entire watershed. Detailed topographic surveys, particle-size data, and suspended-sediment samples were collected at two gaged sites: Monument Creek above Woodmen Road at Colorado Springs, Colorado (USGS gage 07103970), and Sand Creek above mouth at Colorado Springs, Colorado (USGS gage 07105600). These data were used to construct three-dimensional computational models of relatively short channel reaches at each site. The streamflow component of these models predicted a spatially distributed field of water-surface elevation, water velocity, and bed shear stress for a range of stream discharges. Using the model predictions, along with measured particle sizes, the sediment-transport component of the model predicted the suspended-sediment concentration throughout the reach of interest. These computed concentrations were used with predicted flow patterns and channel morphology to

  13. Turbidity and suspended sediment in the upper Esopus Creek watershed, Ulster County, New York

    Science.gov (United States)

    McHale, Michael R.; Siemion, Jason

    2014-01-01

    Suspended-sediment concentrations (SSCs) and turbidity were measured for 2 to 3 years at 14 monitoring sites throughout the upper Esopus Creek watershed in the Catskill Mountains of New York State. The upper Esopus Creek watershed is part of the New York City water-supply system that supplies water to more than 9 million people every day. Turbidity, caused primarily by high concentrations of inorganic suspended particles, is a potential water-quality concern because it colors the water and can reduce the effectiveness of drinking-water disinfection. The purposes of this study were to quantify concentrations of suspended sediment and turbidity levels, to estimate suspended-sediment loads within the upper Esopus Creek watershed, and to investigate the relations between SSC and turbidity. Samples were collected at four locations along the main channel of Esopus Creek and at all of the principal tributaries. Samples were collected monthly and during storms and were analyzed for SSC and turbidity in the laboratory. Turbidity was also measured every 15 minutes at six of the sampling stations with in situ turbidity probes.

  14. Collection of in-Field Impact Loads Acting on a Rugby Wheelchair Frame

    Directory of Open Access Journals (Sweden)

    Francesco Bettella

    2018-02-01

    Full Text Available This work was included in a wider project oriented to the improvement of residual neuromuscular skills in disabled athletes playing wheelchair rugby: the wheelchair rugby Italian national team was involved and tests allowed to analyse the impact loads on a rugby wheelchair frame. The frame of a rugby wheelchair offensive model, made by OffCarr Company, was instrumented with four strain gauge bridges in four different points. Then, three test types were conducted in laboratory: two static calibrations with the application of known loads, the first with horizontal load and the second with vertical load, and a dynamic horizontal calibration, impacting against a fix load cell in order to validate the results of horizontal static calibration. Finally, a test session took place in the field with the collaboration of two team players. The test consisted in voluntary frontal impacts between the two players, starting from 6 meters distance each other. The opponent of the instrumented wheelchair was a defender. From this test, the value of the horizontal load received by the frame in the impact instant was quantified. Moreover, also the vertical load acting on the wheelchair during the rebound of the player after the hit was evaluated: these informations were useful to the wheelchair frame manufacturer for the proper static, impact and fatigue design.

  15. An inventory of suspended sediment stations and type of data analysis for Pennsylvania streams, 1947-1970

    Science.gov (United States)

    Ott, Arthur N.; Commings, Allen B.

    1972-01-01

    Data concerning suspended sediment concentrations and loads, frequency of occurrence of suspended sediment concentrations, and long-term trends of annual suspended sediment loads are important tools for today's environmental manager. These data are required background for those concerned with establishing and enforcing erosion and sedimentation control regulations and sediment concentration or turbidity standards for water-quality criteria, or those concerned with designing for adequate long-term water storage in reservoirs (sediment load), for efficient municipal and industrial plant operation (sediment concentration frequency), etc.This is a compilation of the location, period of record, sampling frequency and type of data synthesis for suspended sediment carried by Pennsylvania streams. Figures 1 and 2 show the approximate locations of sediment sampling stations in Pennsylvania. All of the sediment data listed were collected by the U. S. Geological Survey mainly in cooperation with the following Federal, State, and local agencies.Pennsylvania Department of Environmental Resources     Bureau of Engineering and Construction     Soil and Water Conservation CommissionPennsylvania Department of TransportationCity of PhiladelphiaBrandywine Valley AssociationDelaware Geological SurveyConestoga Valley AssociationLehigh County Soil and Water Conservation DistrictCorps of Engineers, U. S. Army

  16. Contributions of suspended sediment from highway construction and other land uses to the Olentangy River, Columbus, Ohio

    Science.gov (United States)

    Helsel, D.R.

    1985-01-01

    Highway construction within the Olentangy River flood plain in Columbus, Ohio, was projected to be a large source of suspended sediment to the river system. A monitoring program was begun by the U.S. Geological Survey in 1978 to quantify the implacts of construction process. Sediment information was collected daily at six gaging stations located above, below, and within the construction area. Yields of suspended sediment from the active construction area ranged from 9,580 to 15,700 tons per square mile per year. Surrounding suburban terrain yielded 428 to754 tons per square mile per year. However, the size of the construction project was small in comparison to the surrounding suburbs contributing sediment. No more than 4 percent of the yearly downstream suspended-sediment loads were produced by high-way construction during the monitoring periods.

  17. Determination of heavy metals in suspended waste water collected from Oued El Harrach Algiers River by Energy Dispersive X-Ray Fluorescence

    Science.gov (United States)

    Ouziane, S.; Amokrane, A.; Toumert, I.

    2013-12-01

    A preliminary study of the atmospheric pollution in the centre of Algiers is one of the important fields of applications in the environmental science. Nowadays, we need to evaluate the level of the contamination which has an unfavourable effect on physicochemical properties of soils and plants and namely also on human health. In the present work, water samples collected from Oued El-Harrach Algiers River, have been filtered in 0.45 μm Millipore filters to be analysed by Energy Dispersive X-Ray Fluorescence technique using 109Cd radioisotope source. Concentrations of the toxic elements like heavy metals are determined and compared with the published ones values by Yoshida [1] and those obtained using PIXE and NAA techniques [6].

  18. Cable suspended windmill

    Science.gov (United States)

    Farmer, Moses G. (Inventor)

    1990-01-01

    A windmill is disclosed which includes an airframe having an upwind end and a downwind end. The first rotor is rotatably connected to the airframe, and a generator is supported by the airframe and driven by the rotor. The airframe is supported vertically in an elevated disposition by poles which extend vertically upwardly from the ground and support cables which extend between the vertical poles. Suspension cables suspend the airframe from the support cable.

  19. Supporting mobile WEEE collection on demand: A method for multi-criteria vehicle routing, loading and cost optimisation.

    Science.gov (United States)

    Nowakowski, Piotr; Król, Aleksander; Mrówczyńska, Bogna

    2017-11-01

    The task of increasing collection rates of waste electrical and electronic equipment (WEEE) is an important challenge in the global economy, and especially in the European Union where stiffer collection targets set out in a new WEEE directive are to be effective by 2019. As the circular economy approach replaces the linear model, resource recycling activities become a priority in waste management policy. As new techniques and possibilities of waste collection systems emerge, opportunities are created for improving efficiency for collection companies and affording benefits for the environment. A model proposed for mobile WEEE collection in this study considers a multi-criteria approach in developing a cost efficient method for pick up on demand from residents or electrical and electronic equipment (EEE) stores. The algorithm used in this model optimises vehicle routes and helps in selecting a number of vehicles from a heterogeneous fleet, incorporating the WEEE loading problem. Using genetic algorithm and fuzzy logic, this model optimises costs and resources required to complete the WEEE collection assuring timely pick up of the waste equipment. The numerical model is verified in a case study in Opole, a city in the south of Poland. The results show that the proposed model can handle the multiple parameter optimisation problem including operational costs, efficient use of vehicles from a fleet, efficient waste loading in vehicles and residents' satisfaction with timely pick up of the waste equipment from a household. Such system can be successfully applied even for large cities. The algorithm provides an opportunity for writing software or mobile apps design to be used by WEEE collection companies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004-06

    Science.gov (United States)

    Crain, Angela S.

    2010-01-01

    This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Kentucky Department of Agriculture, on nutrients, select pesticides, and suspended sediment in the karst terrane of the Sinking Creek Basin. Streamflow, nutrient, select pesticide, and suspended-sediment data were collected at seven sampling stations from 2004 through 2006. Concentrations of nitrite plus nitrate ranged from 0.21 to 4.9 milligrams per liter (mg/L) at the seven stations. The median concentration of nitrite plus nitrate for all stations sampled was 1.6 mg/L. Total phosphorus concentrations were greater than 0.1 mg/L, the U.S. Environmental Protection Agency's recommended maximum concentration, in 45 percent of the samples. Concentrations of orthophosphates ranged from less than 0.006 to 0.46 mg/L. Concentrations of nutrients generally were larger during spring and summer months, corresponding to periods of increased fertilizer application on agricultural lands. Concentrations of suspended sediment ranged from 1.0 to 1,490 mg/L at the seven stations. Of the 47 pesticides analyzed, 14 were detected above the adjusted method reporting level of 0.01 micrograms per liter (mug/L). Although these pesticides were detected in water-quality samples, they generally were found at less than part-per-billion concentrations. Atrazine was the only pesticide detected at concentrations greater than U.S. Environmental Protection Agency drinking water standard of 3 mug/L, and the maximum detected concentration was 24.6 mug/L. Loads and yields of nutrients, selected pesticides, and suspended sediment were estimated at two mainstream stations on Sinking Creek, a headwater station (Sinking Creek at Rosetta) and a station at the basin outlet (Sinking Creek near Lodiburg). Mean daily streamflow data were available for the estimation of loads and yields from a stream gage at the basin outlet station; however, only periodic instantaneous flow measurements were available for the

  1. Measurement of light attenuation extends the application of suspended sediment monitoring in rivers

    Directory of Open Access Journals (Sweden)

    A. O. Hughes

    2015-03-01

    Full Text Available Turbidity is often monitored continuously as a proxy for suspended sediment in catchment sediment load studies, but is less often applied to measuring optical ‘loads’ as they affect water quality in downstream waters. We added measurements of visual clarity, from which light (beam attenuation can be estimated, to auto-sampler monitoring over storm events in tributary rivers of the Kaipara Harbour, a large barrier enclosed estuary complex in northern New Zealand. This paper presents, for the first time, evidence of the mutual relationships between turbidity, total suspended sediment (TSS, and visual clarity, from water samples collected under event flow conditions. The mutual relationships between turbidity, TSS and visual clarity for our monitoring sites were fairly close over about three orders of magnitude (TSS ranging from about 1–1000 mg L−1. Our results show that visual clarity (and hence light attenuation can be predicted from turbidity, at least as precisely as more traditional predictions of TSS from turbidity. The estimation of light attenuation and corresponding load estimates from visual clarity measurements, for relatively little marginal extra effort, extends the environmental relevance and application of suspended sediment monitoring.

  2. Monosaccharide composition of suspended particles from the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Sankaran, P.D.; Wagh, A.B.

    Neutral carbohydrates were determined as alditol acetates by capillary gas chromatography in the hydrolysates of suspended particulate samples (40) collected from 8 depths (approx 1 to 1,000 m) at 5 stations of the Bay of Bengal. Eight individual...

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

    Science.gov (United States)

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

    2016-01-01

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

  4. Dispersive suspended microextraction.

    Science.gov (United States)

    Yang, Zhong-Hua; Liu, Yu; Lu, Yue-Le; Wu, Tong; Zhou, Zhi-Qiang; Liu, Dong-Hui

    2011-11-14

    A novel sample pre-treatment technique termed dispersive suspended microextraction (DSME) coupled with gas chromatography-flame photometric detection (GC-FPD) has been developed for the determination of eight organophosphorus pesticides (ethoprophos, malathion, chlorpyrifos, isocarbophos, methidathion, fenamiphos, profenofos, triazophos) in aqueous samples. In this method, both extraction and two phases' separation process were performed by the assistance of magnetic stirring. After separating the two phases, 1 μL of the suspended phase was injected into GC for further instrument analysis. Varieties of experiment factors which could affect the experiment results were optimized and the following were selected: 12.0 μL p-xylene was selected as extraction solvent, extraction speed was 1200 rpm, extraction time was 30 s, the restoration speed was 800 rpm, the restoration time was 8 min, and no salt was added. Under the optimum conditions, limits of detections (LODs) varied between 0.01 and 0.05 μg L(-1). The relative standard deviation (RSDs, n=6) ranged from 4.6% to 12.1%. The linearity was obtained by five points in the concentration range of 0.1-100.0 μg L(-1). Correlation coefficients (r) varied from 0.9964 to 0.9995. The enrichment factors (EFs) were between 206 and 243. In the final experiment, the developed method has been successfully applied to the determination of organophosphorus pesticides in wine and tap water samples and the obtained recoveries were between 83.8% and 101.3%. Compared with other pre-treatment methods, DSME has its own features and could achieve satisfied results for the analysis of trace components in complicated matrices. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Chemical concentrations in water and suspended sediment, Green River to Lower Duwamish Waterway near Seattle, Washington, 2016–17

    Science.gov (United States)

    Conn, Kathleen E.; Black, Robert W.; Peterson, Norman T.; Senter, Craig A.; Chapman, Elena A.

    2018-01-05

    From August 2016 to March 2017, the U.S. Geological Survey (USGS) collected representative samples of filtered and unfiltered water and suspended sediment (including the colloidal fraction) at USGS streamgage 12113390 (Duwamish River at Golf Course, at Tukwila, Washington) during 13 periods of differing flow conditions. Samples were analyzed by Washington-State-accredited laboratories for a large suite of compounds, including metals, dioxins/furans, semivolatile compounds including polycyclic aromatic hydrocarbons, butyltins, the 209 polychlorinated biphenyl (PCB) congeners, and total and dissolved organic carbon. Concurrent with the chemistry sampling, water-quality field parameters were measured, and representative water samples were collected and analyzed for river suspended-sediment concentration and particle-size distribution. The results provide new data that can be used to estimate sediment and chemical loads transported by the Green River to the Lower Duwamish Waterway.

  6. Suspended sediment, turbidity, and stream water temperature in the Sauk River Basin, western Washington, water years 2012-16

    Science.gov (United States)

    Jaeger, Kristin L.; Curran, Christopher A.; Anderson, Scott W.; Morris, Scott T.; Moran, Patrick W.; Reams, Katherine A.

    2017-11-01

    The Sauk River is a federally designated Wild and Scenic River that drains a relatively undisturbed landscape along the western slope of the North Cascade Mountain Range, Washington, which includes the glaciated volcano, Glacier Peak. Naturally high sediment loads characteristic of basins draining volcanoes like Glacier Peak make the Sauk River a dominant contributor of sediment to the downstream main stem river, the Skagit River. Additionally, the Sauk River serves as important spawning and rearing habitat for several salmonid species in the greater Skagit River system. Because of the importance of sediment to morphology, flow-conveyance, and ecosystem condition, there is interest in understanding the magnitude and timing of suspended sediment and turbidity from the Sauk River system and its principal tributaries, the White Chuck and Suiattle Rivers, to the Skagit River.Suspended-sediment measurements, turbidity data, and water temperature data were collected at two U.S. Geological Survey streamgages in the upper and middle reaches of the Sauk River over a 4-year period extending from October 2011 to September 2015, and at a downstream location in the lower river for a 5-year period extending from October 2011 to September 2016. Over the collective 5-year study period, mean annual suspended-sediment loads at the three streamgages on the upper, middle, and lower Sauk River streamgages were 94,200 metric tons (t), 203,000 t, and 940,000 t streamgages, respectively. Fine (smaller than 0.0625 millimeter) total suspended-sediment load averaged 49 percent at the upper Sauk River streamgage, 42 percent at the middle Sauk River streamgage, and 34 percent at the lower Sauk River streamgage.

  7. Tidal influence on suspended sediment distribution and dispersal in the northern Andaman Sea and Gulf of Martaban

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Rao, P.S.; Rao, K.H.; Thwin, S.; Rao, N.S.; Raiker, V.

    Surface and water column profiles of suspended matter collected during April-May 2002, and satellite images were used to study factors influencing suspended sediment concentrations (SSCs) and dispersal in the northern Andaman Sea and Gulf...

  8. Assessment of nutrients and suspended sediment conditions in and near the Agassiz National Wildlife Refuge, Northwest Minnesota, 2008–2010

    Science.gov (United States)

    Nustad, Rochelle A.; Galloway, Joel M.

    2012-01-01

    In response to concerns about water-quality impairments that may affect habitat degradation in Agassiz National Wildlife Refuge in northwest Minnesota, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service collected streamflow data, discrete nutrient and suspended- sediment samples, and continuous water-quality data from 2008 to 2010. Constituent loads were estimated for nutrients and suspended sediment using sample data and streamflow data. In addition, a potential water-quality and streamflow monitoring program design was developed for Agassiz National Wildlife Refuge. Results from this study can be used by resource managers to address identified impairments and protect wildlife habitat and public water supply, and may contribute toward developing more effective water-management plans for Agassiz National Wildlife Refuge.

  9. Suspended sediments limit coral sperm availability

    Science.gov (United States)

    Ricardo, Gerard F.; Jones, Ross J.; Clode, Peta L.; Humanes, Adriana; Negri, Andrew P.

    2015-01-01

    Suspended sediment from dredging activities and natural resuspension events represent a risk to the reproductive processes of coral, and therefore the ongoing maintenance of reefal populations. To investigate the underlying mechanisms that could reduce the fertilisation success in turbid water, we conducted several experiments exposing gametes of the corals Acropora tenuis and A. millepora to two sediment types. Sperm limitation was identified in the presence of siliciclastic sediment (230 and ~700 mg L−1), with 2–37 fold more sperm required to achieve maximum fertilisation rates, when compared with sediment-free treatments. This effect was more pronounced at sub-optimum sperm concentrations. Considerable (>45%) decreases in sperm concentration at the water’s surface was recorded in the presence of siliciclastic sediment and a >20% decrease for carbonate sediment. Electron microscopy then confirmed sediment entangled sperm and we propose entrapment and sinking is the primary mechanism reducing sperm available to the egg. Longer exposure to suspended sediments and gamete aging further decreased fertilisation success when compared with a shorter exposure. Collectively, these findings demonstrate that high concentrations of suspended sediments effectively remove sperm from the water’s surface during coral spawning events, reducing the window for fertilisation with potential subsequent flow-on effects for recruitment. PMID:26659008

  10. 36 CFR 1201.20 - What is the extent of the Archivist's authority to compromise debts owed to NARA, or to suspend...

    Science.gov (United States)

    2010-07-01

    ... Archivist's authority to compromise debts owed to NARA, or to suspend or terminate collection action on such... Archivist's authority to compromise debts owed to NARA, or to suspend or terminate collection action on such debts? (a) The Archivist may compromise, suspend, or terminate collection action on those debts owed to...

  11. Geodetic monitoring of suspended particles in rivers

    Science.gov (United States)

    Kamnik, Rok; Maksimova, Daria; Kovačič, Boštjan

    2017-10-01

    There is a trend in modern approach to the management of space of collecting the spatial data, in order to obtain useful information. In this paper a research of suspended particles in the river Drava and Mura will be introduced. The goal is to connect different fields of water management in countries where the rivers Drava and Mura flows in purpose of water management sustainability. The methods such as GNSS for mapping cross sections of the river, the use of ADCP (Acoustic Doppler Current Profiler) measurement system and water sampling to monitor sediment in the water will be presented.

  12. A proposal to improve e-waste collection efficiency in urban mining: Container loading and vehicle routing problems - A case study of Poland.

    Science.gov (United States)

    Nowakowski, Piotr

    2017-02-01

    Waste electrical and electronic equipment (WEEE), also known as e-waste, is one of the most important waste streams with high recycling potential. Materials used in these products are valuable, but some of them are hazardous. The urban mining approach attempts to recycle as many materials as possible, so efficiency in collection is vital. There are two main methods used to collect WEEE: stationary and mobile, each with different variants. The responsibility of WEEE organizations and waste collection companies is to assure all resources required for these activities - bins, containers, collection vehicles and staff - are available, taking into account cost minimization. Therefore, it is necessary to correctly determine the capacity of containers and number of collection vehicles for an area where WEEE need to be collected. There are two main problems encountered in collection, storage and transportation of WEEE: container loading problems and vehicle routing problems. In this study, an adaptation of these two models for packing and collecting WEEE is proposed, along with a practical implementation plan designed to be useful for collection companies' guidelines for container loading and route optimization. The solutions are presented in the case studies of real-world conditions for WEEE collection companies in Poland. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Discharge, suspended sediment, bedload, and water quality in Clear Creek, western Nevada, water years 2010-12

    Science.gov (United States)

    Huntington, Jena M.; Savard, Charles S.

    2015-09-30

    Clear Creek is a small stream that drains the eastern Sierra Nevada near Lake Tahoe, flows roughly parallel to the U.S. Highway 50 corridor, and discharges to the Carson River near Carson City, Nevada. Historical and ongoing development in the drainage basin is thought to be affecting Clear Creek and its sediment-transport characteristics. A baseline study from water years 2004–07 collected and evaluated data at three Clear Creek sampling sites. These data included discharge, selected water-quality parameters, and suspended-sediment concentrations, loads, and yields. This study builds on what was learned from the baseline study in water years 2004–07 and serves as a continuation of the data collection and analyses of the Clear Creek discharge regime and associated water-quality and sediment concentrations and loads during water years 2010–12.

  14. Improving understanding of mixed-land-use watershed suspended sediment regimes: Mechanistic progress through high-frequency sampling.

    Science.gov (United States)

    Kellner, Elliott; Hubbart, Jason A

    2017-11-15

    Given the importance of suspended sediment to biogeochemical functioning of aquatic ecosystems, and the increasing concern of mixed-land-use effects on pollutant loading, there is an urgent need for research that quantitatively characterizes spatiotemporal variation of suspended sediment dynamics in contemporary watersheds. A study was conducted in a representative watershed of the central United States utilizing a nested-scale experimental watershed design, including five gauging sites (n=5) partitioning the catchment into five sub-watersheds. Hydroclimate stations at gauging sites were used to monitor air temperature, precipitation, and stream stage at 30-min intervals during the study (Oct. 2009-Feb. 2014). Streamwater grab samples were collected four times per week, at each site, for the duration of the study (Oct. 2009-Feb. 2014). Water samples were analyzed for suspended sediment using laser particle diffraction. Results showed significant differences (pland use (e.g. urban stormwater dilution) and surficial geology (e.g. supply-controlled spatial variation of particle size). Correlation analyses indicated weak relationships with both hydroclimate and land use, indicating non-linear sediment dynamics. Suspended sediment parameters displayed consistent seasonality during the study, with total concentration decreasing through the growing season and mean particle size inversely tracking air temperature. Likely explanations include vegetation influences and climate-driven weathering cycles. Results reflect unique observations of spatiotemporal variation of suspended sediment particle size class. Such information is crucial for land and water resource managers working to mitigate aquatic ecosystem degradation and improve water resource sustainability in mixed-land-use watersheds globally. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Suspended animation for delayed resuscitation.

    Science.gov (United States)

    Safar, Peter J; Tisherman, Samuel A

    2002-04-01

    'Suspended animation for delayed resuscitation' is a new concept for attempting resuscitation from cardiac arrest of patients who currently (totally or temporarily) cannot be resuscitated, such as traumatic exsanguination cardiac arrest. Suspended animation means preservation of the viability of brain and organism during cardiac arrest, until restoration of stable spontaneous circulation or prolonged artificial circulation is possible. Suspended animation for exsanguination cardiac arrest of trauma victims would have to be induced within the critical first 5 min after the start of cardiac arrest no-flow, to buy time for transport and resuscitative surgery (hemostasis) performed during no-flow. Cardiac arrest is then reversed with all-out resuscitation, usually requiring cardiopulmonary bypass. Suspended animation has been explored and documented as effective in dogs in terms of long-term survival without brain damage after very prolonged cardiac arrest. In the 1990s, the Pittsburgh group achieved survival without brain damage in dogs after cardiac arrest of up to 90 min no-flow at brain (tympanic) temperature of 10 degrees C, with functionally and histologically normal brains. These studies used emergency cardiopulmonary bypass with heat exchanger or a single hypothermic saline flush into the aorta, which proved superior to pharmacologic strategies. For the large number of normovolemic sudden cardiac death victims, which currently cannot be resuscitated, more research in large animals is needed.

  16. Changes in particle size distribution of suspended sediment affected by gravity erosion on the Loess Plateau, China

    Science.gov (United States)

    Guo, Wen-Zhao; Xu, Xiang-Zhou; Liu, Ya-Kun; Zhang, Hong-Wu; Zhu, Ming-Dong

    2017-04-01

    Gravity erosion generates an enormous volume of sediment on the steep hillslopes throughout the world, yet the response from particle size distribution (PSD) of suspended sediment to mass failure remains poorly understood. Here rainfall simulation experiments were conducted on the natural loess slopes to induce a series of mass failures under rainfall intensity of 48 mm h-1, and then an index of enrichment/dilution ratio was used to quantitatively explore the change trend of suspended sediment PSD affected by gravity erosion. To determine suspended sediment, water samples were collected in a polyethylene bottle directly from the gully runoff and channel flow in the pre and during- slope failures events. Then, the particle fractions of samples were done by combining sieving method and photoelectric sedimentometer technique. The results are shown as follows: (1) Gravity erosion has a significant influence on the particle size distribution of suspended sediment. As the mass erosion occurred, the proportion of sand-sized particles was decreased from 71.2 to 50.8%, whereas the proportions of clay and silt were increased remarkably from 1.3 to 7.3% and 27.5 to 41.9%, respectively. Hence the sediment can be more easily transported into channel flow while the suspended sediment load becomes finer as gravitational erosion occurs. (2) The median particle size (d50), sediment heterogeneity (H) and fractal dimensions (D) were significantly correlated with gravity erosion. As a result, d50 was decreased from 0.084 to 0.051 mm, H was increase from 5.6 to 26.8, and D was magnified from 2.60 to 2.78. This implies that mass failure makes the particle size distribution of suspended sediment more nonuniform and irregular. (3) Suspended sediment tended to enrich in the silt and clay fractions, while it diluted in the sand fractions during landslide erosion. Meanwhile, the enrichment/dilution ratios were 13.9 for the clay fractions, 1.4 for clay, and 0.7 for sand. This reflects the

  17. 7 CFR 1206.21 - Suspend.

    Science.gov (United States)

    2010-01-01

    ... part thereof during a particular period of time specified in the rule. ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.21 Suspend. Suspend means to...

  18. Geochemistry of suspended and settling solids in two freshwater lakes.

    NARCIS (Netherlands)

    Koelmans, A.A.

    1998-01-01

    This study describes the 1987–1992 time variationof the bulk chemical composition, levels of heavymetals, arsenic, nitrogen and phosporous insuspended and settling solids in Lake Volkerak andLake Zoom (The Netherlands). Suspended and setlingsolids were collected with continuous flowcentrifuges and

  19. Amino sugars in suspended particulate matter from the Bay of ...

    Indian Academy of Sciences (India)

    Amino sugars (AS)are important constituents of organic matter.However,very little is known about their cycling in marine waters.In this research,we assessed the distribution and cycling of these compounds in waters of the Bay of Bengal.For this purpose,samples of suspended particulate matter (SPM)were collected from 8 ...

  20. Physically based method for measuring suspended-sediment concentration and grain size using multi-frequency arrays of acoustic-doppler profilers

    Science.gov (United States)

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

    2014-01-01

    may be impossible to collect at time intervals less than discharge-independent changes in suspended-sediment concentration can occur (calculating suspended-sediment loads in river at a level of accuracy sufficient for many scientific and management purposes.

  1. 76 FR 28730 - Notice of Intent To Suspend the Agricultural Labor Survey and Farm Labor Reports

    Science.gov (United States)

    2011-05-18

    ... National Agricultural Statistics Service Notice of Intent To Suspend the Agricultural Labor Survey and Farm Labor Reports AGENCY: National Agricultural Statistics Service, USDA. ACTION: Notice of suspension of... Agricultural Statistics Service (NASS) to suspend a currently approved information collection, the Agricultural...

  2. Efecto de la escorrentía sobre la carga de sedimentos en sus­pensión y fósforo en un arroyo de cabecera de una cuenca ru­ral (NO España Effect of runoff on suspended sediment and phosphorus loading in a headwater stream of a rural catchment (NW Spain

    Directory of Open Access Journals (Sweden)

    M.L. Rodríguez-Blanco

    2010-01-01

    Full Text Available Se determinó la carga de sedimentos en suspensión (SS y fósforo (P durante even­tos de lluvia-escorrentía en un arroyo de ca­becera, que drena una cuenca rural ubicada en Galicia (NO España. Asimismo, se trató de conocer las principales fuentes de SS y P exportados. Se observaron acusadas dife­rencias en la carga de SS y P entre eventos, lo cual se asocia con el volumen de esco­rrentía, así como con el desarrollo de surcos y cárcavas efímeras en parcelas de cultivo bien conectadas con la red de drenaje. La carga de SS osciló entre 0,8 y 21,0 t mientras que la de P varió entre 2,5 y 20,0 kg. El fósforo parti­culado (PP mostró relaciones significativas con los SS, lo que indica el origen erosivo de una parte importante de P, especialmente considerando que el PP supone más de un 80% del P exportado en cada evento.This work examines the suspended sedi­ment (SS and phosphorus (P load during rainfall-runoff events in a headwater stream which drains a rural catchment located in Galicia (NW Spain. Another objective is to know the major sources of SS and P ex­ported. Important differences in the SS and P load between events were found, which is associated with the runoff volume, as well as to develop of rills and ephemeral gullies in cultivated fields well connected to the drainage network. The SS load ranged be­tween 0.8 and 21.0 t, while the P load varied between 2.5 and 20.0 kg. The particulate phosphorus (PP showed significant rela­tionship with SS, which indicates the ero­sive origin of P, especially considering that PP means more 80% of P exported each event.

  3. Evaluation of the Xpert HCV Viral Load point-of-care assay from venepuncture-collected and finger-stick capillary whole-blood samples: a cohort study.

    Science.gov (United States)

    Grebely, Jason; Lamoury, Francois M J; Hajarizadeh, Behzad; Mowat, Yasmin; Marshall, Alison D; Bajis, Sahar; Marks, Philippa; Amin, Janaki; Smith, Julie; Edwards, Michael; Gorton, Carla; Ezard, Nadine; Persing, David; Kleman, Marika; Cunningham, Philip; Catlett, Beth; Dore, Gregory J; Applegate, Tanya L

    2017-07-01

    Point-of-care hepatitis C virus (HCV) RNA testing offers an advantage over antibody testing (which only indicates previous exposure), enabling diagnosis of active infection in a single visit. In this study, we evaluated the performance of the Xpert HCV Viral Load assay with venepuncture and finger-stick capillary whole-blood samples. Plasma and finger-stick capillary whole-blood samples were collected from participants in an observational cohort enrolled at five sites in Australia (three drug and alcohol clinics, one homelessness service, and one needle and syringe programme). We compared the sensitivity and specificity of the Xpert HCV Viral Load test for HCV RNA detection by venepuncture and finger-stick collection with the Abbott RealTime HCV Viral Load assay (gold standard). Of 210 participants enrolled between Feb 8, 2016, and July 27, 2016, 150 participants had viral load testing results for the three assays tested. HCV RNA was detected in 45 (30% [95% CI 23-38]) of 150 participants based on Abbott RealTime. Sensitivity of the Xpert HCV Viral Load assay for HCV RNA detection in plasma collected by venepuncture was 100·0% (95% CI 92·0-100·0) and specificity was 99·1% (95% CI 94·9-100·0). Sensitivity of the Xpert HCV Viral Load assay for HCV RNA detection in samples collected by finger-stick was 95·5% (95% CI 84·5-99·4) and specificity was 98·1% (95% CI 93·4-99·8). No adverse events caused by the index test or the reference standard were observed. The Xpert HCV Viral Load test can detect active infection from a finger-stick sample, which represents an advance over antibody-based tests that only indicate past or previous exposure. National Health and Medical Research Council (Australia), Cepheid, South Eastern Sydney Local Health District (Australia), and Merck Sharp & Dohme (Australia). Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Comparison of turbidity to multi-frequency sideways-looking acoustic-Doppler data and suspended-sediment data in the Colorado River in Grand Canyon

    Science.gov (United States)

    Voichick, Nicholas; Topping, David J.

    2010-01-01

    Water clarity is important to biologists when studying fish and other fluvial fauna and flora. Turbidity is an indicator of the cloudiness of water, or reduced water clarity, and is commonly measured using nephelometric sensors that record the scattering and absorption of light by particles in the water. Unfortunately, nephelometric sensors only operate over a narrow range of the conditions typically encountered in rivers dominated by suspended-sediment transport. For example, sediment inputs into the Colorado River in Grand Canyon caused by tributary floods often result in turbidity levels that exceed the maximum recording level of nephelometric turbidity sensors. The limited range of these sensors is one reason why acoustic Doppler profiler instrument data, not turbidity, has been used as a surrogate for suspended sediment concentration and load of the Colorado River in Grand Canyon. However, in addition to being an important water-quality parameter to biologists, turbidity of the Colorado River in Grand Canyon has been used to strengthen the suspended-sediment record through the process of turbidity-threshold sampling; high turbidity values trigger a pump sampler to collect samples of the river at critical times for gathering suspended-sediment data. Turbidity depends on several characteristics of suspended sediment including concentration, particle size, particle shape, color, and the refractive index of particles. In this paper, turbidity is compared with other parameters coupled to suspended sediment, namely suspended-silt and clay concentration and multifrequency acoustic attenuation. These data have been collected since 2005 at four stations with different sediment-supply characteristics on the Colorado River in Grand Canyon. These comparisons reveal that acoustic attenuation is a particularly useful parameter, because it is strongly related to turbidity and it can be measured by instruments that experience minimal fouling and record over the entire range

  5. Temporal and spatial changes of cadmium in the near-bottom suspended matter of the Pomeranian Bay - Arkona Deep system

    Directory of Open Access Journals (Sweden)

    Andrzej Staniszewski

    2000-12-01

    Full Text Available Owing to the high toxicity of cadmium (Cd towards biota and the considerable quantities of this element entering the environment from anthropogenic sources, interest in its biogeochemistry is increasing. This is also true for the marine environment, which serves as a sink for both natural and anthropogenic Cd loads entering the hydrosphere and the atmosphere. The distribution of Cd in the coastal zone of the marine environment is governed primarily by the flux of the so-called fluffy layer suspended matter (FLSM, which spreads across the top of the sea floor as a several-centimetre-thick layer containing highly concentrated suspended matter. Both total contents and solid speciation of Cd was measured in FLSM collected in the Pomeranian Bay - Arkona Deep system (Western Baltic Proper in the course of the three-year-long study. Seasonal changes in the total Cd content (0.5-1.8 µg g–1 dry matter were attributed to the contribution of organic suspensions originating from algal blooms. The decreasing content of Cd in FLSM offshore is due to the input of Cd-rich suspended matter from the River Odra (Oder, and the decreasing organic matter content in FLSM with increasing depth. The contribution of labile fractions (adsorbed and bound to iron III hydroxides was found to be from 50 to 75% of the total content. In view of the substantial mobility and bioavailability of the fractions, this is a highly alarming feature.

  6. Heavy metal content of total suspended air particles in the heavily industrialized town of Gebze, Turkey.

    Science.gov (United States)

    Ergenekon, Pinar; Ulutaş, Kadir

    2014-01-01

    Air pollution is a serious environmental problem in industrialized towns, where a significant portion of the residents live in close proximity to factories and major highways with high traffic load. In this study, the ambient air quality in Gebze, an industrial region with an area of 438 km(2) and a population of 300,000, was characterized in terms for total suspended particulate matter and its composition of trace elements, i.e. Cd, Cr, Cu, Fe, Mn, Ni and Pb. Samples were collected using high volume samplers from March to June 2009 at two sites during the day and the night. A significantly higher Cu concentrations during night suggested that Cu emissions were the result of a local source. The known air toxics, Cd and Ni, had average concentrations (34 and 43 ng/m(3), respectively) higher than proposed by the European Union's ambient air quality standards. These results highlight the potential health risks for the local population.

  7. Self-Suspended Suspensions of Covalently Grafted Hairy Nanoparticles

    KAUST Repository

    Choudhury, Snehashis

    2015-03-17

    © 2015 American Chemical Society. Dispersions of small particles in liquids have been studied continuously for almost two centuries for their ability to simultaneously advance understanding of physical properties of fluids and their widespread use in applications. In both settings, the suspending (liquid) and suspended (solid) phases are normally distinct and uncoupled on long length and time scales. In this study, we report on the synthesis and physical properties of a novel family of covalently grafted nanoparticles that exist as self-suspended suspensions with high particle loadings. In such suspensions, we find that the grafted polymer chains exhibit unusual multiscale structural transitions and enhanced conformational stability on subnanometer and nanometer length scales. On mesoscopic length scales, the suspensions display exceptional homogeneity and colloidal stability. We attribute this feature to steric repulsions between grafted chains and the space-filling constraint on the tethered chains in the single-component self-suspended materials, which inhibits phase segregation. On macroscopic length scales, the suspensions exist as neat fluids that exhibit soft glassy rheology and, counterintuitively, enhanced elasticity with increasing temperature. This feature is discussed in terms of increased interpenetration of the grafted chains and jamming of the nanoparticles. (Chemical Presented).

  8. A Generalized Mathematical Model for the Fracture Problem of the Suspended Highway

    Directory of Open Access Journals (Sweden)

    Zhao Ying

    2017-01-01

    Full Text Available In order to answer dangling fracture problems of highway, the suspended pavement equivalent for non - suspended pavement, through the special boundary conditions has been suspended highway stress field of expression, in accordance with the 3D fracture model of crack formation, and establish a vacant, a general mathematics model for fracture problems of highway and analysis in highway suspended segment weight and vehicle load limit of highway capacity of Pu For overturning road inPu is less than the force of carrying more than compared to the work and fruit Bridge Hydropower Station Road engineering examples to verify suspended highway should force field expressions for the correctness and applicability. The results show that: when the hanging ratio R 0. 243177 limits of Pu design axle load 100kN. When the vertical crack in the vacant in the direction of length greater than 0. 1, the ultimate bearing capacity is less than the design axle load 100kN; when the hanging ratio R is less than 0. 5, the road to local fracture, the ultimate bearing capacity of suspended stress field expressions in solution; when the hanging ratio is greater than or equal to 0. 5, the road does not reach the limit bearing capacity of the whole body; torque shear surface of the effect is far less than the bending moments on shear planes.

  9. Sediment and Mercury Loads to Humbug Creek: A Sierra Nevada Tributary Impacted by the Malakoff Diggins Hydraulic Mine

    Science.gov (United States)

    Monohan, C.; Brown, D. L.; Nepal, H.

    2016-12-01

    Mercury contaminated sediment from legacy gold mines in the Sierra continues to be a source of inorganic mercury (Hg) to the environment. The discharge from Malakoff Diggins, once one of the largest hydraulic mines in California, is a source of Hg and sediment to Humbug Creek. The purpose of this study was to estimate the load of particulate bound Hg and suspended sediment in Humbug Creek for Water Years 2012 and 2013. Grab samples were taken from baseflow conditions and from multiple storm events and analyzed for nonfiltered Hg, filtered Hg and total suspended sediment (TSS) (EPA 1669, EPA 1631, EPA 160.2). A stage discharge relationship was developed for the Humbug Creek gage station over a range of flow conditions. Samples were collected from Humbug Creek upstream of the Malakoff Diggins discharge point, from the discharge point and downstream of the discharge and Humbug Creek confluence at a stream gage. The annual load in Humbug Creek for suspended sediment and particulate bound Hg was calculated at the gage using relationships established with continuously monitored turbidity (15 min data) and grab samples of total suspended sediment (n = 25, R2 = 0.82) and particulate bound Hg (n = 15, R2 = 0.80). The annual load was 100-120 grams of particulate bound Hg and 475,000-575,000 kg of suspended sediment. For both water years, as much as half of the annual sediment load was from a single storm event during which 3-4g of particulate bound mercury was released per day. The contribution of mercury loads from legacy hydraulic gold mines should be quantified as it is a critical source control strategy for California Total Maximum Daily Load programs.

  10. Determining annual suspended sediment and sediment-associated trace element and nutrient fluxes

    Science.gov (United States)

    Horowitz, A.J.

    2008-01-01

    Suspended sediment is a major factor in the biological and geochemical cycling of trace elements and nutrients in aquatic systems. The design of effective studies involving the collection, processing, and subsequent chemical analysis of suspended sediment requires a clear understanding of the problems associated with using this sample medium. This review summarizes the current state of knowledge relative to the various issues/problems associated with the collection of representative suspended sediment samples in fluvial systems. It also addresses issues associated with accurately determining the concentrations and fluxes of sediment-associated trace elements and nutrients.

  11. Measuring and Modeling Suspended Sediment and Nutrient Yields from a Mixed-Land-Use Watershed of the Central U.S.

    Science.gov (United States)

    Zeiger, S. J.; Hubbart, J. A.

    2016-12-01

    A nested-scale watershed study design was used to monitor water quantity and quality of an impaired 3rd order stream in a rapidly urbanizing mixed-land-use watershed of the central USA. Grab samples were collected at each gauging site (n=836 samples x 5 gauging sites) and analyzed for suspended sediment, total phosphorus, and inorganic nitrogen species during the four year study period (2010 - 2013). Observed data were used to quantify relationships between climate, land use and pollutant loading. Additionally, Soil and Water Assessment Tool (SWAT) estimates of monthly stream flow, suspended sediment, total phosphorus, nitrate, nitrite, and ammonium were validated. Total annual precipitation ranged from approximately 650 mm during 2012 (extreme drought year) to 1350 mm during 2010 (record setting wet year) which caused significant (pland use (positive correlate), forested land use (negative correlate), and wetland land use (negative correlate). Results from SWAT model performance assessment indicated calibration was necessary to achieve Nash-Sutcliff Efficiency (NSE) values greater than 0.05 for monthly pollutant loads. Calibrating the SWAT model to multiple gauging sites within the watershed improved estimates of monthly stream flow (NSE=0.83), and pollutant loads (NSE>0.78). However, nitrite and ammonium loads were underestimated by more than four orders of magnitude (NSEland-use watersheds.

  12. Rippling instabilities in suspended nanoribbons

    Science.gov (United States)

    Wang, Hailong; Upmanyu, Moneesh

    2012-11-01

    Morphology mediates the interplay between the structure and electronic transport in atomically thin nanoribbons such as graphene as the relaxation of edge stresses occurs preferentially via out-of-plane deflections. In the case of end-supported suspended nanoribbons that we study here, past experiments and computations have identified a range of equilibrium morphologies, in particular, for graphene flakes, yet a unified understanding of their relative stability remains elusive. Here, we employ atomic-scale simulations and a composite framework based on isotropic elastic plate theory to chart out the morphological stability space of suspended nanoribbons with respect to intrinsic (ribbon elasticity) and engineered (ribbon geometry) parameters, and the combination of edge and body actuation. The computations highlight a rich morphological shape space that can be naturally classified into two competing shapes, bendinglike and twistlike, depending on the distribution of ripples across the interacting edges. The linearized elastic framework yields exact solutions for these rippled shapes. For compressive edge stresses, the body strain emerges as a key variable that controls their relative stability and in extreme cases stabilizes coexisting transverse ripples. Tensile edge stresses lead to dimples within the ribbon core that decay into the edges, a feature of obvious significance for stretchable nanoelectronics. The interplay between geometry and mechanics that we report should serve as a key input for quantifying the transport along these ribbons.

  13. Modelling mussel growth in ecosystems with low suspended matter loads

    Science.gov (United States)

    Duarte, P.; Fernández-Reiriz, M. J.; Filgueira, R.; Labarta, U.

    2010-10-01

    Over the last decades a large number of bivalve growth models were described in the literature with most emphasis on cultivated species with important economic value. These models describe the rates of energy absorption and utilization as a function of environmental conditions. Some of the most important issues in bivalve modelling are water pumping, filtration, pre-ingestive rejection/pseudofaeces production and ingestion of living and non-living organic and inorganic matter. According to some authors, bivalve suspension-feeders may selectively ingest and/or digest different food items whilst making adjustments to maximize the utilization of chlorophyll rich particles. In clear water ecosystems such as the Galician Rias (total particulate matter ( TPM) Galician Rias. Model runs were made for a large number of individual mussels, each with a random parameter set, selected among possible parameter ranges reported in the literature, allowing a quick model calibration and an evaluation of those parameters explaining most of the variance in predicted mussel growth. Obtained results provide a useful feedback for upcoming experimental work where efforts should be concentrated on accurate estimates of these more influential parameters to improve model results.

  14. Numerical 3D flow simulation of attached cavitation structures at ultrasonic horn tips and statistical evaluation of flow aggressiveness via load collectives

    Science.gov (United States)

    Mottyll, S.; Skoda, R.

    2015-12-01

    A compressible inviscid flow solver with barotropic cavitation model is applied to two different ultrasonic horn set-ups and compared to hydrophone, shadowgraphy as well as erosion test data. The statistical analysis of single collapse events in wall-adjacent flow regions allows the determination of the flow aggressiveness via load collectives (cumulative event rate vs collapse pressure), which show an exponential decrease in agreement to studies on hydrodynamic cavitation [1]. A post-processing projection of event rate and collapse pressure on a reference grid reduces the grid dependency significantly. In order to evaluate the erosion-sensitive areas a statistical analysis of transient wall loads is utilised. Predicted erosion sensitive areas as well as temporal pressure and vapour volume evolution are in good agreement to the experimental data.

  15. Suspended and Bedload Sand dynamics in the Mekong River Channel and Export to the Coastal Ocean

    Science.gov (United States)

    Stephens, J. D.; Di Leonardo, D. R.; Weathers, H. D., III; Allison, M. A.

    2016-02-01

    Two field campaigns were conducted in the tidal and estuarine reach of the Song Hau distributary of the Mekong River to examine the dynamics of sand transport and export to the coastal ocean. This study examines variation in suspended sand concentration and net transport with respect to changes in discharge between the October 2014 high discharge and March 2015 low discharge studies, and over semi-diurnal and spring-neap tidal cycles between Can Tho and the Tran De and Dinh An distributary channels in the Mekong Delta. Suspended sand concentrations were measured using a P-61 isokinetic suspended sediment sampler and a Sequoia Scientific LISST-100X used in vertical profiling mode. Stationary ADCP data are used to examine bed stress at cast sites. Bed load transport rates were calculated using a repeat multibeam transect methodology and dune translation rates with flow. Preliminary results indicate that suspended sand concentration increases towards the bed and is positively correlated with increasing shear stress controlled by river discharge and tides. However, sites with non-sandy bottoms, as indicated by multibeam bathymetry, have low suspended sand concentrations, suggesting a close linkage with a bed sand source. Bed load transport rates vary cross-sectionally with shear stress and are linked to dune size. Most bed load transport is taking place in or near the thalweg. The reduction in ebb flows at low discharge and the mantling of sand fields by salinity driven mud deposition, is suspected to control the low suspended sand concentrations observed in March. Results to date suggest that net sand export (suspended plus bed load) to the ocean occurs predominantly during the high discharge monsoon season.

  16. Dynamic transport of suspended sediment by solitary wave: Experimental study

    Science.gov (United States)

    cho, JaeNam; Kim, DongHyun; Hwang, KyuNam; Lee, SeungOh

    2016-04-01

    Solitary waves are able to transport a large amount of suspended sediment when approaching on the beach, which sometimes causes - serious beach erosion, especially in the east and south coastal lines in Korea. But it has rarely been known about the method how to evaluate or estimate the amount of beach erosion caused by solitary waves. Experimental assessment is necessary to comprehend the process of sediment transport on a slope. The prismatic rectangular channel is 12 m long, 0.8 m wide, and 0.75 m high. A sluice gate is applied at prismatic channel in order to produce the solitary waves. Upstream water depth is more than channel water depth and the sluice gate is suddenly opened to simulate conditions of solitary waves. A sand slope with a 1/6 and a sediment thickness is 0.03 m. The experimental sediments are used anthracite (d_50=1.547 mm ,C_u=1.38) and Jumoonjin sand (d_50=0.627 mm ,C_u=1.68). Specific laboratory equipment are designed to collect suspended sediment samples at the same time along the wave propagation at 5 points with evenly space. Each amount of sampling is approximately 25 ml and they are completely dried in oven over 24 hours according to the USGS (Guideline and standard techniques and method 3-C4). Two video cameras (Model No. : Sony, HDR-XR550) are mounted for capturing images at top and side-view when the processes of solitary wave and run up/down on slope. Also, this study are analyzed the correlation between Suspended sediment concentration and turbidity. Also, this study are analyzed the correlation between suspended sediment concentration and turbidity. Turbidity is used to verify suspended sediment concentration. Dimensionless analyses of experimental results carried out in this study. One dimensionless parameter is expressed with pressure of solitary wave on a slope to suspended sediment concentration, which is concerned about lifting force. The other is relate to drag force presenting with run up/down velocity on a slope and

  17. Aerial Photo Utilization in Estimating Suspended Sediment in the Wuryantoro Watershed, Wonogiri

    Directory of Open Access Journals (Sweden)

    Sugiharto Budi Santoso

    2004-01-01

    Full Text Available Suspended sediment load flowing out from a watershed is normally predicated by analysis os suspended sediment of water sample, and the volume of suspended sediment be calculated based on sediment concentration and river discharge. Such field measurements need a lot of field data and they are time consuming. Another method for prediction of suspended sediment by using remote sensing imagery data and recorded rainfall data. The objective of this research is to 1 examine the capability of remote sensing technique to obtain the parameters of the physical data of land in the prediction of suspended sediment; 2 examine the accuracy of the model for prediction suspended sediment. This research is carried out in Wuryantoro watershed, Wonogiri. The main data to obtain the parameters of the physical data of land is infrared aerial photograph on scale 1 : 10.000. the method that used in this research is interpretation of remote sensing imagery data, combined with rainfall data. The result show that the accuracy of landuse is 88.5%, the accuracy of slope is 87.67%. the accuracy of the prediction of suspended sediment by model A3 87.07%, model C1 86.63%, model C2 90.57%, model A8 84.13%, model A9 80.1%, and model C4 78.6%.

  18. Flow cytometric analysis of pollen grains collected from individual bees provides information about pollen load composition and foraging behaviour.

    Science.gov (United States)

    Kron, Paul; Kwok, Allison; Husband, Brian C

    2014-01-01

    Understanding the species composition of pollen on pollinators has applications in agriculture, conservation and evolutionary biology. Current identification methods, including morphological analysis, cannot always discriminate taxa at the species level. Recent advances in flow cytometry techniques for pollen grains allow rapid testing of large numbers of pollen grains for DNA content, potentially providing improved species resolution. A test was made as to whether pollen loads from single bees (honey-bees and bumble-bees) could be classified into types based on DNA content, and whether good estimates of proportions of different types could be made. An examination was also made of how readily DNA content can be used to identify specific pollen species. The method allowed DNA contents to be quickly found for between 250 and 9391 pollen grains (750-28 173 nuclei) from individual honey-bees and between 81 and 11 512 pollen grains (243-34 537 nuclei) for bumble-bees. It was possible to identify a minimum number of pollen species on each bee and to assign proportions of each pollen type (based on DNA content) present. The information provided by this technique is promising but is affected by the complexity of the pollination environment (i.e. number of flowering species present and extent of overlap in DNA content). Nevertheless, it provides a new tool for examining pollinator behaviour and between-species or cytotype pollen transfer, particularly when used in combination with other morphological, chemical or genetic techniques.

  19. Near-continuous suspended sediment monitoring of the Rio Grande using multi-frequency acoustic instrumentation in Big Bend National Park, USA

    Science.gov (United States)

    Dean, D. J.; Topping, D. J.; Schmidt, J. C.; Sabol, T. A.; Griffiths, R. E.

    2011-12-01

    The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, is in disequilibrium. The river in this reach rapidly narrows during low-flow years, and widens during rare, large magnitude floods. One management strategy to improve in-channel habitat for the native ecosystem is to limit the rate and magnitude of channel narrowing during low-flow years through water releases from re-operated upstream dams. The proposed purpose of these dam re-operations is to maximize fine-sediment transport downstream, thereby limiting fine-sediment deposition within the channel and channel narrowing. A suspended-sediment monitoring program consisting of two suspended-sediment gages was established in November 2010 at two sites in Big Bend National Park (BBNP), Texas, to inform these management efforts. Suspended-sediment gages consist of two single-frequency sideways-looking acoustic-Doppler profilers that collect data at 15-minute intervals. Acoustic attenuation is used to calculate silt-and-clay concentration, and acoustic backscatter is used to calculate sand concentration in two size classes. Acoustic attenuation and backscatter are calibrated to velocity-weighted suspended silt-and-clay and sand concentrations in the cross sections near the acoustic instrumentation by using standard depth-integrating samplers deployed according to the Equal-Width-Increment (EWI) method. During flood periods, when depth-integrated samples cannot be collected, automatic pump samplers collect suspended-sediment samples to augment the EWI dataset. Initial analyses indicate that steady, long-duration dam releases are able to transport a consistent load of silt and clay through the study reach in BBNP. However, when tributary flash floods are superimposed on dam releases, the large influx of silt and clay from these tributary floods is not transported through the study reach, even though discharge remains high. When tributary flash floods occur during low-flow periods on

  20. Technological advances in suspended-sediment surrogate monitoring

    Science.gov (United States)

    Gray, John R.; Gartner, Jeffrey W.

    2009-01-01

    Surrogate technologies to continuously monitor suspended sediment show promise toward supplanting traditional data collection methods requiring routine collection and analysis of water samples. Commercially available instruments operating on bulk optic (turbidity), laser optic, pressure difference, and acoustic backscatter principles are evaluated based on cost, reliability, robustness, accuracy, sample volume, susceptibility to biological fouling, and suitable range of mass concentration and particle size distribution. In situ turbidimeters are widely used. They provide reliable data where the point measurements can be reliably correlated to the river's mean cross section concentration value, effects of biological fouling can be minimized, and concentrations remain below the sensor's upper measurement limit. In situ laser diffraction instruments have similar limitations and can cost 6 times the approximate $5000 purchase price of a turbidimeter. However, laser diffraction instruments provide volumetric-concentration data in 32 size classes. Pressure differential instruments measure mass density in a water column, thus integrating substantially more streamflow than a point measurement. They are designed for monitoring medium-to-large concentrations, are generally unaffected by biological fouling, and cost about the same as a turbidimeter. However, their performance has been marginal in field applications. Acoustic Doppler profilers use acoustic backscatter to measure suspended sediment concentrations in orders of magnitude more streamflow than do instruments that rely on point measurements. The technology is relatively robust and generally immune to effects of biological fouling. Cost of a single-frequency device is about double that of a turbidimeter. Multifrequency arrays also provide the potential to resolve concentrations by clay silt versus sand size fractions. Multifrequency hydroacoustics shows the most promise for revolutionizing collection of continuous

  1. Particle size distribution of suspended solids in the Chesapeake Bay entrance and adjacent shelf waters

    Science.gov (United States)

    Byrnes, M. R.; Oertel, G. F.

    1981-01-01

    Characteristics of suspended solids, including total suspended matter, total suspended inorganics, total suspended organics, particle size distribution, and the presence of the ten most prominent particle types were determined. Four research vessels simultaneously collected samples along four transects. Samples were collected within a 2-hour period that coincided with the maximum ebb penetration of Chesapeake Bay outwelling. The distribution of primary and secondary particle size modes indicate the presence of a surface or near-surface plume, possibly associated with three sources: (1) runoff, (2) resuspension of material within the Bay, and/or (3) resuspension of material in the area of shoals at the Bay mouth. Additional supportive evidence for this conclusion is illustrated with ocean color scanner data.

  2. 76 FR 39377 - Notice of Intent To Suspend the July Sheep and Goat Survey, and Postpone the Renewal of the...

    Science.gov (United States)

    2011-07-06

    ... National Agricultural Statistics Service Notice of Intent To Suspend the July Sheep and Goat Survey, and... Agricultural Statistics Service (NASS) to suspend one currently approved information collection, (July Sheep...: Suspension of July Sheep and Goat Survey and postponement of Census of Aquaculture and TOTAL surveys. OMB...

  3. 76 FR 78610 - Notice of Intent To Suspend the Nursery Production, the Nursery and Floriculture Chemical Use...

    Science.gov (United States)

    2011-12-19

    ... National Agricultural Statistics Service Notice of Intent To Suspend the Nursery Production, the Nursery... Service (NASS) to suspend currently approved information collections for all Nursery and Christmas Tree Production Surveys along with the Nursery and Floriculture Chemical Use Survey approved under OMB 0535-0244...

  4. The significance of suspended organic sediments to turbidity, sediment flux, and fish-feeding behavior

    Science.gov (United States)

    Mary Ann Madej; Margaret Wilzbach; Kenneth Cummins; Colleen Ellis; Samantha Hadden

    2007-01-01

    For over three decades, geologists, hydrologists and stream ecologists have shown significant interest in suspended load in running waters. Physical scientists have focused on turbidity, the development of sediment-rating curves and estimation of sediment yields, often as an indicator of changing land uses (Beschta 1981). Stream ecologists, on the other hand, have...

  5. Influence of near-bottom re-suspended sediment on benthic light availability

    DEFF Research Database (Denmark)

    Pedersen, Troels Møller; Gallegos, Charles L.; Nielsen, Søren Laurentius

    2012-01-01

    Increased light attenuation in the water column is a common consequence of the increased organic loading that accompanies anthropogenic eutrophication in coastal systems. Frequently, the best water quality correlate of the light attenuation coefficient is the total suspended solids, even in syste...

  6. Discriminating silt-and-clay from suspended-sand in rivers using side-looking acoustic profilers

    Science.gov (United States)

    Wright, Scott A.; Topping, David J.; Williams, Cory A.

    2010-01-01

    The ability to accurately monitor suspended-sediment flux in rivers is needed to support many types of studies, because the sediment that typically travels in suspension affects geomorphology and aquatic habitat in a variety of ways (e.g. bank and floodplain deposition, bar morphology, light penetration and primary productivity, tidal wetland deposition in the context of sea-level rise, sediment-associated contaminants, reservoir sedimentation and potential erosion during dam removal, among others). In addition, human-induced changes to the landscape have resulted in substantially altered suspended-sediment loads (Syvitski et al., 2005). Thus, accurate monitoring of suspended-sediment flux is necessary for informed resource management of rivers. Because of this need, a variety of techniques have been developed and applied for suspendedsediment monitoring. The traditional approach in the United States, which was developed and has been used extensively by the U.S. Geological Survey (USGS), is to collect an isokinetic, velocity-weighted sample from a river cross-section, analyze the sample in the laboratory, and use water-discharge records to compute a record of suspended-sediment flux (Guy, 1969, Guy, 1970, Edwards and Glysson, 1999, Porterfield, 1972). The labor and expense associated with this traditional approach is substantial such that the number of USGS gages reporting daily records of suspended-sediment flux decreased from 364 in 1981 to 120 in 2003 (Osterkamp et al., 2004). Also, the traditional sampling approach is limited with respect to the temporal resolution that can be achieved, thus requiring the use of approximate relations between suspended-sediment concentration and water discharge to fill gaps between samples. To address these limitations, several indirect or "surrogate" measures have been investigated (see e.g. Gray and Gartner, 2009) most notably optical backscatter (i.e. turbidity), laser-diffraction, and acoustic backscatter. These indirect

  7. Influenza A viral loads in respiratory samples collected from patients infected with pandemic H1N1, seasonal H1N1 and H3N2 viruses

    Directory of Open Access Journals (Sweden)

    Chuchottaworn Charoen

    2010-04-01

    Full Text Available Abstract Background Nasopharyngeal aspirate (NPA, nasal swab (NS, and throat swab (TS are common specimens used for diagnosis of respiratory virus infections based on the detection of viral genomes, viral antigens and viral isolation. However, there is no documented data regarding the type of specimen that yields the best result of viral detection. In this study, quantitative real time RT-PCR specific for M gene was used to determine influenza A viral loads present in NS, NPA and TS samples collected from patients infected with the 2009 pandemic H1N1, seasonal H1N1 and H3N2 viruses. Various copy numbers of RNA transcripts derived from recombinant plasmids containing complete M gene insert of each virus strain were assayed by RT-PCR. A standard curve for viral RNA quantification was constructed by plotting each Ct value against the log quantity of each standard RNA copy number. Results Copy numbers of M gene were obtained through the extrapolation of Ct values of the test samples against the corresponding standard curve. Among a total of 29 patients with severe influenza enrolled in this study (12 cases of the 2009 pandemic influenza, 5 cases of seasonal H1N1 and 12 cases of seasonal H3N2 virus, NPA was found to contain significantly highest amount of viral loads and followed in order by NS and TS specimen. Viral loads among patients infected with those viruses were comparable regarding type of specimen analyzed. Conclusion Based on M gene copy numbers, we conclude that NPA is the best specimen for detection of influenza A viruses, and followed in order by NS and TS.

  8. Self-suspended permanent magnetic FePt ferrofluids

    KAUST Repository

    Dallas, Panagiotis

    2013-10-01

    We present the synthesis and characterization of a new class of self-suspended ferrofluids that exhibit remanent magnetization at room temperature. Our system relies on the chemisorption of a thiol-terminated ionic liquid with very low melting point on the surface of L10 FePt nanoparticles. In contrast, all types of ferrofluids previously reported employ either volatile solvents as the suspending media or superparamagnetic iron oxide nanoparticles (that lacks permanent magnetization) as the inorganic component. The ferrofluids do not show any sign of flocculation or phase separation, despite the strong interactions between the magnetic nanoparticles due to the strong chemisorption of the ionic liquid as evidenced by Raman spectroscopy and thermal analysis. Composites with high FePt loading (40 and 70. wt%) exhibit a pseudo solid-like rheological behavior and high remanent magnetization values (10.1 and 12.8. emu/g respectively). At lower FePt loading (12. wt%) a liquid like behavior is observed and the remanent and saturation magnetization values are 3.5 and 6.2. emu/g, respectively. The magnetic and flow properties of the materials can be easily fine tuned by controlling the type and amount of FePt nanoparticles used. © 2013 Elsevier Inc.

  9. Resuspension and transport of suspended solids in Eurajoensalmi Bay. Final report of monitoring activities in 2009-2011; Resuspensio ja kiintoaineen kulkeutuminen Eurajoensalmessa. Vesistoemittausten loppuraportti

    Energy Technology Data Exchange (ETDEWEB)

    Mykkanen, J.; Kiirikki, M.; Lindfors, A. [Luode Consulting Oy, Espoo (Finland)

    2012-11-15

    The goal of monitoring activities carried out in Eurajoensalmi Bay was to indentify factors affecting dispersal of river waters and suspended solid matter in the estuary area. In addition to suspended solids load and dispersal of river water, also release of sedimented particles from the sea bed in resuspension was studied. River water quality and discharge as well as resuspension in Eurajoensalmi estuary area were monitored with Luode automatic monitoring stations equipped with water quality, water level, wave height and weather sensors. Dynamics of Eurajoensalmi estuary area was studied by installing profiling current meters (ADCP) and water quality sensors to the sea floor at the mouth of Eurajoensalmi. Spatial variation of surface water quality was monitored with a flow-through method from a moving vessel and manual profiling several times during the monitoring period. Collected data was processed and used in determining suspended solids balance of Eurajoensalmi Bay. The balance was determined by creating a regression model for water exchange and sediment flux over the cross section at the mouth of Eurajoensalmi. Regression model was created also to determine resuspension in Eurajoensalmi area. Sediment flux and resuspension were modeled using long term wind data from Kylmaepihlaja meteorological station as a variable to determine overall sediment balance of Eurajoensalmi.

  10. Characterization of streamflow, suspended sediment, and nutrients entering Galveston Bay from the Trinity River, Texas, May 2014–December 2015

    Science.gov (United States)

    Lucena, Zulimar; Lee, Michael T.

    2017-02-21

    The U.S. Geological Survey (USGS), in cooperation with the Texas Water Development Board and the Galveston Bay Estuary Program, collected streamflow and water-quality data at USGS streamflow-gaging stations in the lower Trinity River watershed from May 2014 to December 2015 to characterize and improve the current understanding of the quantity and quality of freshwater inflow entering Galveston Bay from the Trinity River. Continuous streamflow records at four USGS streamflow-gaging stations were compared to quantify differences in streamflow magnitude between upstream and downstream reaches of the lower Trinity River. Water-quality conditions were characterized from discrete nutrient and sedi­ment samples collected over a range of hydrologic conditions at USGS streamflow-gaging station 08067252 Trinity River at Wallisville, Tex. (hereinafter referred to as the “Wallisville site”), approximately 4 river miles upstream from where the Trinity River enters Galveston Bay.Based on streamflow records, annual mean outflow from Livingston Dam into the lower Trinity River was 2,240 cubic feet per second (ft3/s) in 2014 and 22,400 ft3/s in 2015, the second lowest and the highest, respectively, during the entire period of record (1966–2015). During this study, only about 54 percent of the total volume measured at upstream sites was accounted for at the Wallisville site as the Trinity River enters Galveston Bay. This difference in water volumes between upstream sites and the Wallisville site indicates that at high flows a large part of the volume released from Lake Livingston does not reach Galveston Bay through the main channel of the Trinity River. These findings indicate that water likely flows into wetlands and water bodies surrounding the main channel of the Trinity River before reaching the Wallisville site and is being stored or discharged through other channels that flow directly into Galveston Bay.To characterize suspended-sediment concentrations and loads in

  11. The effects of sample scheduling and sample numbers on estimates of the annual fluxes of suspended sediment in fluvial systems

    Science.gov (United States)

    Horowitz, Arthur J.; Clarke, Robin T.; Merten, Gustavo Henrique

    2015-01-01

    Since the 1970s, there has been both continuing and growing interest in developing accurate estimates of the annual fluvial transport (fluxes and loads) of suspended sediment and sediment-associated chemical constituents. This study provides an evaluation of the effects of manual sample numbers (from 4 to 12 year−1) and sample scheduling (random-based, calendar-based and hydrology-based) on the precision, bias and accuracy of annual suspended sediment flux estimates. The evaluation is based on data from selected US Geological Survey daily suspended sediment stations in the USA and covers basins ranging in area from just over 900 km2 to nearly 2 million km2 and annual suspended sediment fluxes ranging from about 4 Kt year−1 to about 200 Mt year−1. The results appear to indicate that there is a scale effect for random-based and calendar-based sampling schemes, with larger sample numbers required as basin size decreases. All the sampling schemes evaluated display some level of positive (overestimates) or negative (underestimates) bias. The study further indicates that hydrology-based sampling schemes are likely to generate the most accurate annual suspended sediment flux estimates with the fewest number of samples, regardless of basin size. This type of scheme seems most appropriate when the determination of suspended sediment concentrations, sediment-associated chemical concentrations, annual suspended sediment and annual suspended sediment-associated chemical fluxes only represent a few of the parameters of interest in multidisciplinary, multiparameter monitoring programmes. The results are just as applicable to the calibration of autosamplers/suspended sediment surrogates currently used to measure/estimate suspended sediment concentrations and ultimately, annual suspended sediment fluxes, because manual samples are required to adjust the sample data/measurements generated by these techniques so that they provide depth-integrated and cross

  12. Monitoring suspended sediments and turbidity in Sahelian basins

    Science.gov (United States)

    Robert, Elodie; Grippa, Manuela; Kergoat, Laurent; Martinez, Jean-Michel; Pinet, Sylvain; Nogmana, Soumaguel

    2017-04-01

    Suspended matter can carry viruses and bacteria that are pathogenic to humans and can foster their development. Therefore, turbidity can be considered a vector of microbiological contaminants, which cause diarrheal diseases, and it can be used as a proxy for fecal bacteria. Few studies have focused on water turbidity in rural Africa, where many cases of intestinal parasitic infections are due to the consumption of unsafe water from ponds, reservoirs, lakes and rivers. Diarrheal diseases are indeed the second cause of infant mortality in sub-Saharan Africa. Furthermore, in this region, environment survey is minimal or inexistent. Monitoring water turbidity therefore represents a challenge for health improvement. Turbidity refers to the optical properties of water and it is well suited to monitoring by remote sensing. Because it varies in space and time and because the small water bodies (remote sensing and questions the methods developed for less turbid waters. In addition, high aerosol loadings (mineral dust and biomass burning) may be detrimental to turbidity retrieval in this region because of inaccurate atmospheric corrections. We propose a method to monitor water quality of Sahelian ponds, lakes and rivers using in-situ and remote sensing data, which is tested at different sites for which in-situ water turbidity and suspended sediments concentration (SSSC) measurements are acquired. Water sample are routinely collected at two sites within the AMMA-CATCH observatory part of the Réseau de Bassin Versants (RBV) French network: the Agoufou pond in northern Mali (starting September 2014), and the Niger River at Niamey in Niger (starting June 2015). These data are used to evaluate different indexes to derive water turbidity from the reflectance in the visible and infrared bands of high resolution optical sensors (LANDSAT, SENTINEL2). The temporal evolution of the turbidity of ponds, lakes and rivers is well captured at the seasonal and interannual scales with the

  13. Mass transfer within electrostatic precipitators: in-flight adsorption of mercury by charged suspended particulates.

    Science.gov (United States)

    Clack, Herek L

    2006-06-01

    Electrostatic precipitation is the dominant method of particulate control used for coal combustion, and varying degrees of mercury capture and transformation have been reported across ESPs. Nevertheless, the fate of gas-phase mercury within an ESP remains poorly understood. The present analysis focuses on the gas-particle mass transfer that occurs within a charged aerosol in an ESP. As a necessary step in gas-phase mercury adsorption or transformation, gas-particle mass transfer-particularly in configurations other than fixed beds-has received far less attention than studies of adsorption kinetics. Our previous analysis showed that only a small fraction of gas-phase mercury entering an ESP is likelyto be adsorbed by collected particulate matter on the plate electrodes. The present simplified analysis provides insight into gas-particle mass transfer within an ESP under two limiting conditions: laminar and turbulent fluid flows. The analysis reveals that during the process of particulate collection, gas-particle mass transfer can be quite high, easily exceeding the mass transfer to ESP plate electrodes in most cases. Decreasing particle size, increasing particle mass loading, and increasing temperature all result in increased gas-particle mass transfer. The analysis predicts significantly greater gas-particle mass transfer in the laminar limitthan in the turbulent limit; however, the differences become negligible under conditions where other factors, such as total mass of suspended particulates, are the controlling mass transfer parameters. Results are compared to selected pilot- and full-scale sorbent injection data.

  14. [Modulatory Effect of Mouse Compact Bone-derived Suspending MSC on T Cells and It's Related Mechanisms].

    Science.gov (United States)

    Li, Xin; Wu, Wen-Qing; Ding, Li; Liu, Yuan-Lin; Mao, Ning; Zhang, Yi; Zhu, Heng; Ning, Shou-Bin

    2016-04-01

    To investigate the modulatory effect of the MSC derived from low attaching culture systems (suspending MSC) on T lymphocytes and the related mechanisms. The suspending MSC were generated from mouse compact bones by using low attaching plates and adherent cell culture flasks, respectively. The morphology of suspending MSC was observed under the inverted microscope and the cells were induced to differentiate into osteoblasts and adipocytes. Further, the surface antigen profile of MSC was analyzed with flow cytometry. In addition, the culture medium (CM) of suspending MSC and adherent MSC was collected and added into the activated T cell cultures before detection of the proliferation by CFSE assay. Moreover, the modulaory effects of the CM on the T cell-derived cytokines were detected by quantitative PCR. Also, the mRNA expression of cytokines of MSC was detected. The suspending MSC grew in floating cell spheres and differentiated into osteoblasts and adipocytes in the induction medium. Furthermore, the suspending MSC shared the typical immuno-phenotype with their adherent counterparts. In addition, the results of CFSE assay demonstrated that suspending MSC derived CM suppressed ConA induced T cell proliferation. The results of quantitative PCR revealed that suspending MSC expressed transforming factor β1 and interleukin-6 at a higher level and suppressed the T cell expressing interferon γ and interleukine-17A. The suspending MSC exerted an unique modulatoy effect on T cells, which is quite different to adherent MSC.

  15. Remote Sensing of Suspended Sediment Dynamics in the Mississippi Sound

    Science.gov (United States)

    Merritt, D. N.; Skarke, A. D.; Silwal, S.; Dash, P.

    2016-02-01

    The Mississippi Sound is a semi-enclosed estuary between the coast of Mississippi and a chain of offshore barrier islands with relatively shallow water depths and high marine biodiversity that is wildly utilized for commercial fishing and public recreation. The discharge of sediment-laden rivers into the Mississippi Sound and the adjacent Northern Gulf of Mexico creates turbid plumes that can extend hundreds of square kilometers along the coast and persist for multiple days. The concentration of suspended sediment in these coastal waters is an important parameter in the calculation of regional sediment budgets as well as analysis of water-quality factors such as primary productivity, nutrient dynamics, and the transport of pollutants as well as pathogens. The spectral resolution, sampling frequency, and regional scale spatial domain associated with satellite based sensors makes remote sensing an ideal tool to monitor suspended sediment dynamics in the Northern Gulf of Mexico. Accordingly, the presented research evaluates the validity of published models that relate remote sensing reflectance with suspended sediment concentrations (SSC), for similar environmental settings, with 51 in situ observations of SSC from the Mississippi Sound. Additionally, regression analysis is used to correlate additional in situ observations of SSC in Mississippi Sound with coincident observations of visible and near-infrared band reflectance collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Aqua satellite, in order to develop a site-specific empirical predictive model for SSC. Finally, specific parameters of the sampled suspended sediment such as grain size and mineralogy are analyzed in order to quantify their respective contributions to total remotely sensed reflectance.

  16. Sediment and Hydraulic Measurements with Computed Bed Load on the Missouri River, Sioux City to Hermann, 2014

    Science.gov (United States)

    2017-05-01

    by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR . ERDC/CHL TR-17-8 iii Contents...24 Table 11. Suspended sediment load distributed by grain size and soil type – April 30, 2014. ............. 28 Table 12. Suspended sediment...load distributed by grain size and soil type – June 5, 2014. .............. 28 Table 13. Suspended sediment load distributed by grain size and soil type

  17. Monitoring suspended sediment transport in an ice-affected river using acoustic Doppler current profilers

    Science.gov (United States)

    Moore, S. A.; Ghareh Aghaji Zare, S.; Rennie, C. D.; Ahmari, H.; Seidou, O.

    2013-12-01

    Quantifying sediment budgets and understanding the processes which control fluvial sediment transport is paramount to monitoring river geomorphology and ecological habitat. In regions that are subject to freezing there is the added complexity of ice. River ice processes impact flow distribution, water stage and sediment transport. Ice processes typically have the largest impact on sediment transport and channel morphodynamics when ice jams occur during ice cover formation and breakup. Ice jams may restrict flow and cause local acceleration when released. Additionally, ice can mechanically scour river bed and banks. Under-ice sediment transport measurements are lacking due to obvious safety and logistical reasons, in addition to a lack of adequate measurement techniques. Since some rivers can be covered in ice during six months of the year, the lack of data in winter months leads to large uncertainty in annual sediment load calculations. To address this problem, acoustic profilers are being used to monitor flow velocity, suspended sediment and ice processes in the Lower Nelson River, Manitoba, Canada. Acoustic profilers are ideal for under-ice sediment flux measurements since they can be operated autonomously and continuously, they do not disturb the flow in the zone of measurement and acoustic backscatter can be related to sediment size and concentration. In March 2012 two upward-facing profilers (1200 kHz acoustic Doppler current profiler, 546 KHz acoustic backscatter profiler) were installed through a hole in the ice on the Nelson River, 50 km downstream of the Limestone Generating Station. Data were recorded for four months, including both stable cover and breakup periods. This paper presents suspended sediment fluxes calculated from the acoustic measurements. Velocity data were used to infer the vertical distribution of sediment sizes and concentrations; this information was then used in the interpretation of the backscattered intensity data. It was found that

  18. SUSPENDED AND DISSOLVED MATTER FLUXES IN THE UPPER SELENGA RIVER BASIN

    Directory of Open Access Journals (Sweden)

    Sergey Chalov

    2012-01-01

    Full Text Available We synthesized recent field-based estimates of the dissolved ions (K+ Na+ Ca2+ Mg2+ Cl- SO42- HCO3-, biogens (NO3-, NO2-, PO43-(C, mg/l, heavy metal (Fesum, Mn, Pb and dissolved load (DL, kg/day, as far as suspended sediment concentration (SSC, mg/l and suspended load (SL, kg/day along upper Selenga river and its tributaries based on literature review and preliminary results of our 2011 field campaign. The crucial task of this paper is to provide full review of Russian, Mongolian and English-language literature which concern the matter fluxes in the upper part of Selenga river (within Mongolia. The exist estimates are compared with locations of 3 main matter sources within basin: mining and industry, river-bank erosion and slope wash. The heaviest increase of suspended and dissolved matter transport is indicated along Tuul-Orkhon river system (right tributary of the Selenga River where Mongolia capital Ulanbaatar, gold mine Zaamar and few other mines are located. In measurement campaigns conducted in 2005, 2006 and 2008 the increase directly after the Zaamar mining site was between 167 to 383 kg/day for Fe, between 15 and 5260 kg/day for Mn. Our field campaign indicated increase of suspended load along Tuul river from 4280 kg/day at the upstream point to 712000 kg/day below Ulaanbaatar and Zaamar. The results provide evidence on a potential connection between increased dissolved and suspended matter fluxes in transboundary rivers and zones of matter supply at industrial and mining centers, along eroded river banks and pastured lands. The gaps in the understanding of matter load fluxes within this basin are discussed with regards to determining further goals of hydrological and geochemical surveys.

  19. Suspended sediment dynamics on a seasonal scale in the Mandovi and Zuari estuaries, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Shynu, R.; Kessarkar, P.M.; Sundar, D.; Michael, G.S.; Narvekar, T.; Blossom, V.; Mehra, P.

    Suspended particulate matter (SPM) collected at regular stations from the Mandovi and Zuari estuaries indicates that the peaks of high SPM coincide with peaks of high rainfall and low salinity and also with peaks of moderate/low rainfall coupled...

  20. Watershed characteristics and water-quality trends and loads in 12 watersheds in Gwinnett County, Georgia

    Science.gov (United States)

    Joiner, John K.; Aulenbach, Brent T.; Landers, Mark N.

    2014-01-01

    The U.S. Geological Survey, in cooperation with Gwinnett County Department of Water Resources, established a Long-Term Trend Monitoring (LTTM) program in 1996. The LTTM program is a comprehensive, long-term, water-quantity and water-quality monitoring program designed to document and analyze the hydrologic and water-quality conditions of selected watersheds of Gwinnett County, Georgia. Water-quality monitoring initially began in six watersheds and was expanded to another six watersheds in 2001. As part of the LTTM program, streamflow, precipitation, water temperature, specific conductance, and turbidity were measured continuously at the 12 watershed monitoring stations for water years 2004–09. In addition, discrete water-quality samples were collected seasonally from May through October (summer) and November through April (winter), including one base-flow and three stormflow event composite samples, during the study period. Samples were analyzed for nutrients (nitrogen and phosphorus), total organic carbon, trace elements (total lead and total zinc), total dissolved solids, and total suspended sediment (total suspended solids and suspended-sediment concentrations). The sampling scheme was designed to identify variations in water quality both hydrologically and seasonally. The 12 watersheds were characterized for basin slope, population density, land use for 2009, and the percentage of impervious area from 2000 to 2009. Precipitation in water years 2004–09 was about 18 percent below average, and the county experienced exceptional drought conditions and below average runoff in water years 2007 and 2008. Watershed water yields, the percentage of precipitation that results in runoff, typically are lower in low precipitation years and are higher for watersheds with the highest percentages of impervious areas. A comparison of base-flow and stormflow water-quality samples indicates that turbidity and concentrations of total ammonia plus organic nitrogen, total

  1. Tracking suspended particle transport via radium isotopes ((226)Ra and (228)Ra) through the Apalachicola-Chattahoochee-Flint River system.

    Science.gov (United States)

    Peterson, Richard N; Burnett, William C; Opsahl, Stephen P; Santos, Isaac R; Misra, Sambuddha; Froelich, Philip N

    2013-02-01

    Suspended particles in rivers can carry metals, nutrients, and pollutants downstream which can become bioactive in estuaries and coastal marine waters. In river systems with multiple sources of both suspended particles and contamination sources, it is important to assess the hydrologic conditions under which contaminated particles can be delivered to downstream ecosystems. The Apalachicola-Chattahoochee-Flint (ACF) River system in the southeastern United States represents an ideal system to study these hydrologic impacts on particle transport through a heavily-impacted river (the Chattahoochee River) and one much less impacted by anthropogenic activities (the Flint River). We demonstrate here the utility of natural radioisotopes as tracers of suspended particles through the ACF system, where particles contaminated with arsenic (As) and antimony (Sb) have been shown to be contributed from coal-fired power plants along the Chattahoochee River, and have elevated concentrations in the surficial sediments of the Apalachicola Bay Delta. Radium isotopes ((228)Ra and (226)Ra) on suspended particles should vary throughout the different geologic provinces of this river system, allowing differentiation of the relative contributions of the Chattahoochee and Flint Rivers to the suspended load delivered to Lake Seminole, the Apalachicola River, and ultimately to Apalachicola Bay. We also use various geochemical proxies ((40)K, organic carbon, and calcium) to assess the relative composition of suspended particles (lithogenic, organic, and carbonate fractions, respectively) under a range of hydrologic conditions. During low (base) flow conditions, the Flint River contributed 70% of the suspended particle load to both the Apalachicola River and the bay, whereas the Chattahoochee River became the dominant source during higher discharge, contributing 80% of the suspended load to the Apalachicola River and 62% of the particles entering the estuary. Neither of these hydrologic

  2. Flow modelling to estimate suspended sediment travel times for two Canadian Deltas

    Directory of Open Access Journals (Sweden)

    S. R. Fassnacht

    2000-01-01

    Full Text Available The approximate travel times for suspended sediment transport through two multi-channel networks are estimated using flow modelling. The focus is on the movement of high sediment concentrations that travel rapidly downstream. Since suspended sediment transport through river confluences and bifurcation movement is poorly understood, it is assumed that the sediment moves at approximately the average channel velocity during periods of high sediment load movement. Calibration of the flow model is discussed, with an emphasis on the incorporation of cross-section data, that are not referenced to a datum, using a continuous water surface profile. Various flow regimes are examined for the Mackenzie and the Slave River Deltas in the Northwest Territories, Canada, and a significant variation in travel times is illustrated. One set of continuous daily sediment measurements throughout the Mackenzie Delta is used to demonstrate that the travel time estimates are reasonable. Keywords: suspended sediment; multi-channel river systems; flow modelling; sediment transport

  3. Recent changes of suspended sediment yields in the Upper Yangtze River and its headwater tributaries

    Science.gov (United States)

    Zhang, X.; Tang, Q.; Long, Y.; He, X.; Wen, A.

    2015-03-01

    Suspended sediment yields in the Upper Yangtze River and its four headwater tributaries (i.e. Jinsha, Min, Jialing and Wu) have declined significantly during recent decades. Compared with 1956-1970, mean annual suspended sediment yield during 2001-2011 was reduced by 84% in the Upper Yangtze River at Yichang, by 34% in the Jinsha at Pingshan, by 84% in the Jialing at Beibei, by 75% in the Wu at Wulong, and by 48% in the Min at Gaochang. Linking these observed decadal changes of runoff discharge and suspended sediment load to dam construction and multiple environmental rehabilitation projects (e.g. soil-water conservation, reforestation) during the past decades, it can be concluded that the construction of large dams on the main stem and major tributaries of the Upper Yangtze River has played a principal role in the reduction of fluvial suspended sediment yields, while the environment rehabilitation projects may make limited contributions to the changes in suspended sediment yields, except for the Jialing River.

  4. Recent changes of suspended sediment yields in the Upper Yangtze River and its headwater tributaries

    Directory of Open Access Journals (Sweden)

    X. Zhang

    2015-03-01

    Full Text Available Suspended sediment yields in the Upper Yangtze River and its four headwater tributaries (i.e. Jinsha, Min, Jialing and Wu have declined significantly during recent decades. Compared with 1956–1970, mean annual suspended sediment yield during 2001–2011 was reduced by 84% in the Upper Yangtze River at Yichang, by 34% in the Jinsha at Pingshan, by 84% in the Jialing at Beibei, by 75% in the Wu at Wulong, and by 48% in the Min at Gaochang. Linking these observed decadal changes of runoff discharge and suspended sediment load to dam construction and multiple environmental rehabilitation projects (e.g. soil-water conservation, reforestation during the past decades, it can be concluded that the construction of large dams on the main stem and major tributaries of the Upper Yangtze River has played a principal role in the reduction of fluvial suspended sediment yields, while the environment rehabilitation projects may make limited contributions to the changes in suspended sediment yields, except for the Jialing River.

  5. Anomalies in Trace Metal and Rare-Earth Loads below a Waste-Water Treatment Plant

    Science.gov (United States)

    Antweiler, R.; Writer, J. H.; Murphy, S.

    2013-12-01

    The changes in chemical loads were examined for 54 inorganic elements and compounds in a 5.4-km reach of Boulder Creek, Colorado downstream of a waste water treatment plant (WWTP) outfall. Elements were partitioned into three categories: those showing a decrease in loading downstream, those showing an increase, and those which were conservative, at least over the length of the study reach. Dissolved loads which declined - generally indicative of in-stream loss via precipitation or sorption - were typically rapid (occurring largely before the first sampling site, 2.3 km downstream); elements showing this behavior were Bi, Cr, Cs, Ga, Ge, Hg, Se and Sn. These results were as expected before the experiment was performed. However, a large group (28 elements, including all the rare-earth elements, REE, except Gd) exhibited dissolved load increases indicating in-stream gains. These gains may be due to particulate matter dissolving or disaggregating, or that desorption is occurring below the WWTP. As with the in-stream loss group, the processes tended to be rapid, typically occurring before the first sampling site. Whole-water samples collected concurrently also had a large group of elements which showed an increase in load downstream of the WWTP. Among these were most of the group which had increases in the dissolved load, including all the REE (except Gd). Because whole-water samples include both dissolved and suspended particulates within them, increases in loads cannot be accounted for by invoking desorption or disaggregation mechanisms; thus, the only source for these increases is from the bed load of the stream. Further, the difference between the whole-water and dissolved loads is a measure of the particulate load, and calculations show that not only did the dissolved and whole-water loads increase, but so did the particulate loads. This implies that at the time of sampling the bed sediment was supplying a significant contribution to the suspended load. In general

  6. Temporal variability and spatial distribution of suspended matter and organic C pool in the Zambezi River

    Science.gov (United States)

    Teodoru, Cristian R.; Bouillon, Steven; Borges, Alberto V.; Darchambeau, François; Nyoni, Frank C.; Nyambe, Imasiku

    2014-05-01

    It is increasingly recognized that rivers are active components of global carbon (C) cycling, able of processing, emitting into atmosphere, and transporting to the oceans large quantities of both organic and inorganic carbon derived from the surrounding terrestrial landscape. Although tropical rivers contribute with more than half to the global freshwater discharge to the oceans, there is surprisingly little information on biogeochemistry and C cycling of those systems, especially for Africa. As part of a broader study on the biogeochemistry of large African river basins, we present here data on temporal and spatial variability of total suspended matter (TSM), particulate (POC) and dissolved organic C (DOC) in the Zambezi River (length = 2900 km, catchment area > 1.4 million km2, annual discharge ~ 4150 m3/s) in relation to physico-chemical proprieties (conductivity, oxygen, pH, total alkalinity), bacterial respiration, primary production and net aquatic metabolism. Data were collected along the entire river stretch during 2012 and 2013, and over 2 climatic (dry and wet) seasons to constrain the interannual variability, seasonality and spatial heterogeneity of the investigated parameters, and at two monitoring stations: one on the Zambezi mainstream, and one on the Kafue River (major tributary of the Zambezi; total length ~ 1900 km, catchment ~ 156, 000 km2, annual discharge = 350 m3/s), both located several km upstream their confluence. During the two sampled years, TSM concentrations varied from 1.6 mg/L to 110 mg/L (mean 17 in 2012 and 29 mg/L in 2013) and were systematically higher in the river mainstream (mean 21 mg/L and 36 mg/L in 2012 and 2013, respectively) compared to both reservoirs (the Kariba and the Cahora Bassa) where TSM concentrations average 2.5 mg/L. Despite the disturbance along the aquatic continuum caused by the presence of the two man-made reservoirs, a distinct longitudinal pattern was observed during both years, with TSM increasing

  7. Extending the turbidity record: making additional use of continuous data from turbidity, acoustic-Doppler, and laser diffraction instruments and suspended-sediment samples in the Colorado River in Grand Canyon

    Science.gov (United States)

    Voichick, Nicholas; Topping, David J.

    2014-01-01

    Turbidity is a measure of the scattering and absorption of light in water, which in rivers is primarily caused by particles, usually sediment, suspended in the water. Turbidity varies significantly with differences in the design of the instrument measuring turbidity, a point that is illustrated in this study by side-by-side comparisons of two different models of instruments. Turbidity also varies with changes in the physical parameters of the particles in the water, such as concentration, grain size, grain shape, and color. A turbidity instrument that is commonly used for continuous monitoring of rivers has a light source in the near-infrared range (860±30 nanometers) and a detector oriented 90 degrees from the incident light path. This type of optical turbidity instrument has a limited measurement range (depending on pathlength) that is unable to capture the high turbidity levels of rivers that carry high suspended-sediment loads. The Colorado River in Grand Canyon is one such river, in which approximately 60 percent of the range in suspended-sediment concentration during the study period had unmeasurable turbidity using this type of optical instrument. Although some optical turbidimeters using backscatter or other techniques can measure higher concentrations of suspended sediment than the models used in this study, the maximum turbidity measurable using these other turbidimeters may still be exceeded in conditions of especially high concentrations of suspended silt and clay. In Grand Canyon, the existing optical turbidity instruments remain in use in part to provide consistency over time as new techniques are investigated. As a result, during these periods of high suspended-sediment concentration, turbidity values that could not be measured with the optical turbidity instruments were instead estimated from concurrent acoustic attenuation data collected using side-looking acoustic-Doppler profiler (ADP) instruments. Extending the turbidity record to the full

  8. Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland

    Science.gov (United States)

    Overeem, I.; Hudson, B. D.; Syvitski, J. P. M.; Mikkelsen, A. B.; Hasholt, B.; van den Broeke, M. R.; Noël, B. P. Y.; Morlighem, M.

    2017-11-01

    Limited measurements along Greenland's remote coastline hamper quantification of the sediment and associated nutrients draining the Greenland ice sheet, despite the potential influence of river-transported suspended sediment on phytoplankton blooms and carbon sequestration. Here we calibrate satellite imagery to estimate suspended sediment concentration for 160 proglacial rivers across Greenland. Combining these suspended sediment reconstructions with numerical calculations of meltwater runoff, we quantify the amount and spatial pattern of sediment export from the ice sheet. We find that, although runoff from Greenland represents only 1.1% of the Earth's freshwater flux, the Greenland ice sheet produces approximately 8% of the modern fluvial export of suspended sediment to the global ocean. Sediment loads are highly variable between rivers, consistent with observed differences in ice dynamics and thus with control by glacial erosion. Rivers that originate from deeply incised, fast-moving glacial tongues form distinct sediment-export hotspots: just 15% of Greenland's rivers transport 80% of the total sediment load of the ice sheet. We conclude that future acceleration of melt and ice sheet flow may increase sediment delivery from Greenland to its fjords and the nearby ocean.

  9. Estuarine Suspended Sediment Dynamics: Observations Derived from over a Decade of Satellite Data

    Directory of Open Access Journals (Sweden)

    Anthony Reisinger

    2017-12-01

    Full Text Available Suspended sediment dynamics of Corpus Christi Bay, Texas, USA, a shallow-water wind-driven estuary, were investigated by combining field and satellite measurements of total suspended solids (TSS. An algorithm was developed to transform 500-m Moderate Resolution Imaging Spectroradiometer (MODIS Aqua satellite reflectance data into estimated TSS values. The algorithm was developed using a reflectance ratio regression of MODIS Band 1 (red and Band 3 (green with TSS measurements (n = 54 collected by the Texas Commission on Environmental Quality for Corpus Christi Bay and other Texas estuaries. The algorithm was validated by independently collected TSS measurements during the period of 2011–2014 with an uncertainty estimate of 13%. The algorithm was applied to the period of 2002–2014 to create a synoptic time series of TSS for Corpus Christi Bay. Potential drivers of long-term variability in suspended sediment were investigated. Median and IQR composites of suspended sediments were generated for seasonal wind regimes. From this analysis it was determined that long-term, spatial patterns of suspended sediment in the estuary are related to wind-wave resuspension during the predominant northerly and prevalent southeasterly seasonal wind regimes. The impact of dredging is also apparent in long-term patterns of Corpus Christi Bay as concentrations of suspended sediments over dredge spoil disposal sites are higher and more variable than surrounding areas, which is most likely due to their less consolidated sediments and shallower depths requiring less wave energy for sediment resuspension. This study highlights the advantage of how long-synoptic time series of TSS can be used to elucidate the major drivers of suspended sediments in estuaries.

  10. 9 CFR 201.81 - Suspended registrants.

    Science.gov (United States)

    2010-01-01

    ... 201.81 Animals and Animal Products GRAIN INSPECTION, PACKERS AND STOCKYARDS ADMINISTRATION (PACKERS AND STOCKYARDS PROGRAMS), DEPARTMENT OF AGRICULTURE REGULATIONS UNDER THE PACKERS AND STOCKYARDS ACT Services § 201.81 Suspended registrants. No stockyard owner, packer, market agency, or dealer shall employ...

  11. Electrodialytic remediation of suspended mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, Adrian; Pino, Denisse

    2008-01-01

    experiment at 40 mA, with approximately 137.5 g mine tailings on dry basis. The removal for a static (baseline) experiment only amounted 15% when passing approximately the same amount of charge through 130 g of mine tailings. The use of air bubbling to keep the tailings suspended increased the removal...

  12. Environmental toxicology: Acute effects of suspended particulate ...

    African Journals Online (AJOL)

    ... from the control values were found significant at 99% confidence level. Possible inhalatory problems are thus anticipated from prolonged accumulation of the dust in the respiratory system. KEY WORDS: Environmental toxicology, Suspended particulate matter, Dust analysis, Hematological indices, Wister albino rats. Bull.

  13. Environmental toxicology: Acute effects of suspended particulate ...

    African Journals Online (AJOL)

    The elemental contents of suspended particulate matter (dust) samples from Maiduguri, Nigeria, were determined which showed appreciably high levels for especially Pb, Fe, Cu, Zn, K, Ca, and. Na. Wister albino rats were exposed to graded doses of phosphate buffered saline carried dust particles. The hematological ...

  14. A depth integrated model for suspended transport

    NARCIS (Netherlands)

    Galappatti, R.

    1983-01-01

    A new depth averaged model for suspended sediment transport in open channels has been developed based on an asymptotic solution to the two dimensional convection-diffusion equation in the vertical plane. The solution for the depth averaged concentration is derived from the bed boundary condition and

  15. The Shape of Breasts Suspended in Liquid

    NARCIS (Netherlands)

    De Kleijn, S.C.; Rensen, W.H.J.

    2007-01-01

    Philips has designed an optical mammography machine. In this machine the breast is suspended into a cup in which the measurements take place. A special fluid is inserted into the cup to prevent the light from going around the breast instead of going through it but this fluid also weakens the signal.

  16. Flow Laminarization and Acceleration by Suspended Particles

    NARCIS (Netherlands)

    Bertsch, M.; Hulshof, J.; Prostokishin, V.M.

    2015-01-01

    In [Comm. Appl. Math. Comput. Sci., 4(2009), pp. 153-175], Barenblatt presents a model for partial laminarization and acceleration of shear flows by the presence of suspended particles of different sizes, and provides a formal asymptotic analysis of the resulting velocity equation. In the present

  17. Emulsifying and Suspending Properties of Enterolobium ...

    African Journals Online (AJOL)

    Background:The thermodynamic instability of emulsions and suspensions necessitate the incorporation of emulsifiers and suspending agents respectively, in order to stabilize the formulations and ensure administration of accurate doses. Objective:Enterolobium cyclocarpum gum was characterized and evaluated for its ...

  18. Remote Sensing Analysis of Temperature and Suspended Sediment Concentration in Ayeyarwady River in Myanmar

    Science.gov (United States)

    Thanda Ko, Nyein; Rutten, Martine

    2017-04-01

    Detailed spatial coverage of water quality parameters are crucial to better manage rivers. However, collection of water quality parameters is both time consuming and costly for large rivers. This study demonstrates that Operational Land Image (OLI) Sensor on board of Landsat 8 can be successfully applied for the detection of spatial patterns of water temperature as well as suspended sediment concentration (SSC) using the Ayeyarwady river, Myanmar as a case study. Water temperature estimation was obtained from the brightness thermal Band 10 by using the Split-Window algorithm. The study finds that there is a close agreement between the remote sensing temperature and in-situ temperature with relative error in the range from 4.5% to 8.2%. The sediment load of Ayeyarwady river is ranked as the third-largest sediment load among the world's rivers but there is very little known about this important parameter, due to a lack of adequate gauge data. The single band reflectance of Landsat image (Band 5) seems a good indicator for the estimation of SSC with relative error in the range of less than 10% but the developed empirical formula by the power relation with the only seven ground reference points is uncertain to apply for the entire river basin. It is to note that an important constraint for the sediment analysis is the availability of spatial and temporal ground reference data. Future studies should also focus on the improvement of ground reference data points to become more reliable, because most of the river in Asia, especially in Myanmar, don't have readily available continuous ground sediment data points due to lack of measurement gauge stations through the river.

  19. Progress towards Acoustic Suspended Sediment Transport Monitoring: Fraser River, BC

    Science.gov (United States)

    Attard, M. E.; Venditti, J. G.; Church, M. A.; Kostaschuk, R. A.

    2011-12-01

    Our ability to predict the timing and quantity of suspended sediment transport is limited because fine sand, silt and clay delivery are supply limited, requiring empirical modeling approaches of limited temporal stability. A solution is the development of continuous monitoring techniques capable of tracking sediment concentrations and grain-size. Here we examine sediment delivery from upstream sources to the lower Fraser River. The sediment budget of the lower Fraser River provides a long-term perspective of the net changes in the channels and in sediment delivery to Fraser Delta. The budget is based on historical sediment rating curves developed from data collected from 1965-1986 by the Water Survey of Canada. We explore the possibility of re-establishing the sediment-monitoring program using hydro-acoustics by evaluating the use of a 300 kHz side-looking acoustic Doppler current profiler (aDcp), mounted just downstream of the sand-gravel transition at Mission, for continuous measurement of suspended sediment transport. Complementary field observations include conventional bottle sampling with a P-63 sampler, vertical profiles with a downward-looking 600 kHz aDcp, and 1200 kHz aDcp discharge measurements. We have successfully completed calibration of the downward-looking aDcp with the P-63 samples; the side-looking aDcp signals remain under investigation. A comparison of several methods for obtaining total sediment flux indicates that suspended sediment concentration (SSC) closely follows discharge through the freshet and peaks in total SSC and sand SSC coincide with peak measurements of discharge. Low flows are dominated by fine sediment and grain size increases with higher flows. This research assesses several techniques for obtaining sediment flux and contributes to the understanding of sediment delivery to sand-bedded portions of the river.

  20. Energy content of suspended detritus from Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Sumitra-Vijayaraghavan; Royan, J.P.

    Energy components of suspended matter included phytoplankton, zooplankton and detritus inclusive of microorganisms adsorbed to detritus. Of these, detritus contributed most of the energy (98%). The average caloric content of suspended detritus...

  1. The suspended sentence in French Criminal Law

    Directory of Open Access Journals (Sweden)

    Jovašević Dragan

    2016-01-01

    Full Text Available From the ancient times until today, criminal law has provided different criminal sanctions as measures of social control. These coercive measures are imposed on the criminal offender by the competent court and aimed at limitting the offender's rights and freedoms or depriving the offender of certain rights and freedoms. These sanctions are applied to the natural or legal persons who violate the norms of the legal order and injure or endanger other legal goods that enjoy legal protection. In order to effectively protect social values, criminal legislations in all countries predict a number of criminal sanctions. These are: 1 imprisonment, 2 precautions, 3 safety measures, 4 penalties for juveniles, and 5 sanctions for legal persons. Apart and instead of punishment, warning measures have a significant role in the jurisprudence. Since they emerged in the early 20th century in the system of criminal sanctions, there has been an increase in their application to criminal offenders, especially when it comes to first-time offenders who committed a negligent or accidental criminal act. Warnings are applied in case of crimes that do not have serious consequences, and whose perpetrators are not hardened and incorrigible criminals. All contemporary criminal legislations (including the French legilation provide a warning measure of suspended sentence. Suspended sentence is a conditional stay of execution of sentence of imprisonment for a specified time, provided that the convicted person does not commit another criminal offense and fulfills other obligations. This sanction applies if the following two conditions are fulfilled: a forma! -which is attached to the sentence of imprisonment; and b material -which is the court assessment that the application of this sanction is justified and necessary in a particular case. In many modern criminal legislations, there are two different types of suspended (conditional sentence: 1 ordinary (classical suspended

  2. Impact of suspended solids concentration on sludge filterability in Full-scale membrane bioreactors

    NARCIS (Netherlands)

    Lousada Ferreira, M.D.C.; Van Lier, J.B.; Van der Graaf, J.H.J.M.

    2015-01-01

    The relation between activated sludge filterability and mixed liquor suspended solids (MLSS) concentration in membrane bioreactors (MBRs) is framed in a single hypothesis, explaining results seemingly contradictory. A total of 44 activated sludge samples were collected and analyzed on a variety of

  3. Levels of As, Pb, Cd and Fe in Suspended Particulate Matter (SPM ...

    African Journals Online (AJOL)

    Suspended Particulate Matter (SPM) collected from three different artisans' workshops was analyzed for As, Cd, Pb and Fe by Atomic Absorption Spectrophotometry (AAS). The range of SPM concentrations for the three workshops was 583-20,166Bg/m3. The highest concentrations of these elements were observed in Motor ...

  4. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: methodology and applications.

    Science.gov (United States)

    Mahler, B J; Van Metre, P C

    2003-04-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport.

  5. Impact of robotics and a suspended lead suit on physician radiation exposure during percutaneous coronary intervention

    Energy Technology Data Exchange (ETDEWEB)

    Madder, Ryan D., E-mail: ryan.madder@spectrumhealth.org; VanOosterhout, Stacie; Mulder, Abbey; Elmore, Matthew; Campbell, Jessica; Borgman, Andrew; Parker, Jessica; Wohns, David

    2017-04-15

    Background: Reports of left-sided brain malignancies among interventional cardiologists have heightened concerns regarding physician radiation exposure. This study evaluated the impact of a suspended lead suit and robotic system on physician radiation exposure during percutaneous coronary intervention (PCI). Methods: Real-time radiation exposure data were prospectively collected from dosimeters worn by operating physicians at the head- and chest-level during consecutive PCI cases. Exposures were compared in three study groups: 1) manual PCI performed with traditional lead apparel; 2) manual PCI performed using suspended lead; and 3) robotic PCI performed in combination with suspended lead. Results: Among 336 cases (86.6% manual, 13.4% robotic) performed over 30 weeks, use of suspended lead during manual PCI was associated with significantly less radiation exposure to the chest and head of operating physicians than traditional lead apparel (chest: 0.0 [0.1] μSv vs 0.4 [4.0] μSv, p < 0.001; head: 0.5 [1.9] μSv vs 14.9 [51.5] μSv, p < 0.001). Chest-level radiation exposure during robotic PCI performed in combination with suspended lead was 0.0 [0.0] μSv, which was significantly less chest exposure than manual PCI performed with traditional lead (p < 0.001) or suspended lead (p = 0.046). In robotic PCI the median head-level exposure was 0.1 [0.2] μSv, which was 99.3% less than manual PCI performed with traditional lead (p < 0.001) and 80.0% less than manual PCI performed with suspended lead (p < 0.001). Conclusions: Utilization of suspended lead and robotics were observed to result in significantly less radiation exposure to the chest and head of operating physicians during PCI. - Highlights: • Use of suspended lead during manual PCI reduced cranial radiation among operators by 97%. • Robotic PCI reduced cranial radiation among operators by 99%. • Suspended lead and robotics together achieved the lowest levels of radiation exposure.

  6. Storage and residence time of suspended sediment in gravel bars of Difficult Run, VA

    Science.gov (United States)

    George, J.; Benthem, A.; Pizzuto, J. E.; Skalak, K.

    2016-12-01

    Reducing the export of suspended sediment is an important consideration for restoring water quality to the Chesapeake Bay, but sediment budgets for in-channel landforms are poorly constrained. We quantified fine (mapped in a 150m headwater reach at Miller Heights (bankfull width 11m; total bar volume 114 m3) and 6 gravel bars were mapped in a 160m reach downstream near Leesburg Pike (bankfull width 19m; total bar volume 210 m3). Grain size analyses of surface and subsurface samples from 2 bars at each reach indicate an average suspended sediment content of 55%, suggesting a total volume of suspended sediment stored in the mapped bars to be 178 m3, or 283000 kg, comprising 5% of the average annual suspended sediment load of the two study reaches. Estimates of the annual bedload flux at Miller Heights based on stream gaging records and the Wilcock-Crowe bedload transport equation imply that the bars are entirely reworked at least annually. Scour chains installed in 2 bars at each site (a total of 50 chains) recorded scour and fill events during the winter and spring of 2016. These data indicate that 38% of the total volume of the bars is exchanged per year, for a residence time of 2.6 ± 1.2 years, a value we interpret as the residence time of suspended sediment stored in the bars. These results are supported by mapping of topographic changes derived from structure-from-motion analyses of digital aerial imagery. Storage in alluvial bars therefore represents a significant component of the suspended sediment budget of mid-Atlantic streams.

  7. Estimating total suspended sediment yield with probability sampling

    Science.gov (United States)

    Robert B. Thomas

    1985-01-01

    The ""Selection At List Time"" (SALT) scheme controls sampling of concentration for estimating total suspended sediment yield. The probability of taking a sample is proportional to its estimated contribution to total suspended sediment discharge. This procedure gives unbiased estimates of total suspended sediment yield and the variance of the...

  8. Optomechanics for thermal characterization of suspended graphene

    Science.gov (United States)

    Dolleman, Robin J.; Houri, Samer; Davidovikj, Dejan; Cartamil-Bueno, Santiago J.; Blanter, Yaroslav M.; van der Zant, Herre S. J.; Steeneken, Peter G.

    2017-10-01

    The thermal response of graphene is expected to be extremely fast due to its low heat capacity and high thermal conductivity. In this work, the thermal response of suspended single-layer graphene membranes is investigated by characterization of their mechanical motion in response to a high-frequency modulated laser. A characteristic delay time τ between the optical intensity and mechanical motion is observed, which is attributed to the time required to raise the temperature of the membrane. We find, however, that the measured time constants are significantly larger than the predicted ones based on values of the specific heat and thermal conductivity. In order to explain the discrepancy between measured and modeled τ , a model is proposed that takes a thermal boundary resistance at the edge of the graphene drum into account. The measurements provide a noninvasive way to characterize thermal properties of suspended atomically thin membranes, providing information that can be hard to obtain by other means.

  9. Development of an Integrated Suspended Sediment Sampling System - Prototype Results

    Science.gov (United States)

    Nerantzaki, Sofia; Moirogiorgou, Konstantia; Efstathiou, Dionissis; Giannakis, George; Voutsadaki, Stella; Zervakis, Michalis; Sibetheros, Ioannis A.; Zacharias, Ierotheos; Karatzas, George P.; Nikolaidis, Nikolaos P.

    2015-04-01

    The Mediterranean region is characterized by a unique micro-climate and a complex geologic and geomorphologic environment caused by its position in the Alpine orogenesis belt. Unique features of the region are the temporary rivers that are dry streams or streams with very low flow for most of the time over decadal time scales. One of their key characteristics is that they present flashy hydrographs with response times ranging from minutes to hours. It is crucial to monitor flash-flood events and observe their behavior since they can cause environmental degradation of the river's wider location area. The majority of sediment load is transferred during these flash events. Quantification of these fluxes through the development of new measuring devices is of outmost importance as it is the first step for a comprehensive understanding of the water quality, the soil erosion and erosion sources, and the sediment and nutrient transport routes. This work proposes an integrated suspended sediment sampling system which is implemented in a complex semi-arid Mediterranean watershed (i.e. the Koiliaris River Basin of Crete) with temporary flow tributaries and karstic springs. The system consists of sensors monitoring water stage and turbidity, an automated suspended sediment sampler, and an online camera recording video sequence of the river flow. Water stage and turbidity are continuously monitored and stage is converted to flow with the use of a rating curve; when either of these variables exceeds certain thresholds, the pump of the sediment sampler initiates sampling with a rotation proportional to the stage (flow weighted sampling). The water passes through a filter that captures the sediment, the solids are weighted after each storm and the data are converted to a total sediment flux. At the same time, the online camera derives optical measurements for the determination of the two-dimensional river flow velocity and the spatial sediment distribution by analyzing the Hue

  10. Sedimentation of suspended solids in ultrasound field

    Directory of Open Access Journals (Sweden)

    Vikulina Vera

    2018-01-01

    Full Text Available Physical and chemical effects of aquatic environment that occur in an ultrasonic field change the sedimentation rate of coagulated suspension. This might only happen in case of cavitation of ultrasonic filed that causes a change of potentials of the medium. Research of the influence of ultrasonic vibrations on coagulation of suspended solids within water purification allows expanding their scope of implementation. The objective of the research is to estimate the effect of ultrasound on the sedimentation of the suspended solids, to determine of the efficiency of the process in relation to the dose of the coagulant, and to calculate the numerical values of the constants in the theoretical equation. The experiment condition was held in the water with the clay substances before the introduction of the coagulant. The method of magnetostriction ultrasonic generator was applied to receive ultrasonic vibration. Estimate of concentration of clay particles in water was performed using photometry. As a result of the research, the obtained data allow determining the increase in efficiency of suspended particles sedimentation related to the dose of coagulant, depending on time of ultrasonic treatment. The experiments confirmed the connection between the effect of sedimentation in the coagulation process, the coagulant dose and the time of scoring. Studies have shown that the increase in the duration of ultrasonic treatment causes a decrease of administered doses of coagulant.

  11. Impact of robotics and a suspended lead suit on physician radiation exposure during percutaneous coronary intervention.

    Science.gov (United States)

    Madder, Ryan D; VanOosterhout, Stacie; Mulder, Abbey; Elmore, Matthew; Campbell, Jessica; Borgman, Andrew; Parker, Jessica; Wohns, David

    Reports of left-sided brain malignancies among interventional cardiologists have heightened concerns regarding physician radiation exposure. This study evaluated the impact of a suspended lead suit and robotic system on physician radiation exposure during percutaneous coronary intervention (PCI). Real-time radiation exposure data were prospectively collected from dosimeters worn by operating physicians at the head- and chest-level during consecutive PCI cases. Exposures were compared in three study groups: 1) manual PCI performed with traditional lead apparel; 2) manual PCI performed using suspended lead; and 3) robotic PCI performed in combination with suspended lead. Among 336 cases (86.6% manual, 13.4% robotic) performed over 30weeks, use of suspended lead during manual PCI was associated with significantly less radiation exposure to the chest and head of operating physicians than traditional lead apparel (chest: 0.0 [0.1] μSv vs 0.4 [4.0] μSv, probotic PCI performed in combination with suspended lead was 0.0 [0.0] μSv, which was significantly less chest exposure than manual PCI performed with traditional lead (probotic PCI the median head-level exposure was 0.1 [0.2] μSv, which was 99.3% less than manual PCI performed with traditional lead (probotics were observed to result in significantly less radiation exposure to the chest and head of operating physicians during PCI. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Biogenic vanadium in total suspended particulate matter from Cabo Frio upwelling region, Southeast, Brazil

    Science.gov (United States)

    Sella, Silvia M.; Neves, Alessandra F.; Moreira, Josino Costa; Silva-Filho, Emmanoel V.

    In this work total suspended particulate (TSP) was collected during a year, in two municipalities located in a coastal region of Rio de Janeiro State, Southeast, Brazil, from February 2004 to January 2005. Two sites were chosen: site 1 located in front of the sea and representative of sea salt spray influence; site 2 in a tall booth of a highway representing vehicle exhaust influence. Samples were collected in glass fibre filters using Hi-Vol samplers and stored. 1/8 of those loaded filters were cut and digested in a microwave oven. The extract obtained was used to determine metal Ca, Cu, Mo, Mn, Ti, V, Zn and K concentration in the atmosphere. The results showed that TSP levels in site 1 (23.1-659 μg m -3) was higher than in site 2 (24.5-55.6 μg m -3) due to marine aerosol which is responsible for particle emissions with higher diameter. Vanadium was the only element studied whose concentration were higher in site 1 (0.840-20.9 ng m -3) compared to site 2 (0.655-7.07 ng m -3). The highest vanadium concentrations in site 1 were obtained during upwelling events, with NE winds predominance at high speed, which indicates the influence of this phenomena in V presence in the atmosphere. Principal components analysis was able to identify atmospheric particulate sources distributed in four factors. In site 1, those factors explain 86.5% of total data variance and indicate two sources: continental and marine. In site 2, those factors explain 89.2% of total data variance and indicate that vehicle exhaust is the main metals source in the atmosphere.

  13. Nutrients and Suspended Solids in Surface Waters of the Upper Illinois River Basin in Illinois, Indiana, and Wisconsin, 1978-97

    Science.gov (United States)

    Sullivan, Daniel J.

    2000-01-01

    A retrospective analysis of selected data on nutrients and suspended solids in surface waters of the upper Illinois River Basin was done as part of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program. Approximately 91 percent of the upper Illinois River Basin is drained by three principal rivers: the Kankakee (and its major tributary, the Iroquois), the Des Plaines, and the Fox. The data analyzed were collected by the Illinois Environmental Protection Agency (IEPA), which operates 39 monitoring sites in the study area as part of its Ambient Water-Quality Monitoring Network, and included analyses for total ammonia nitrogen, total nitriteplus- nitrate nitrogen, total ammonia-plus-organic (total Kjeldahl) nitrogen, dissolved and total phosphorus, and total suspended solids and volatile solids. Nutrient and suspended-sediment data collected by the USGS as part of the upper Illinois River Basin NAWQA pilot study from 1987-90 were compared to IEPA data. For the 1978-97 period, in general, nutrient concentrations, with the exception of nitrate, were highest at streams in the urban areas of the Des Plaines River Basin. Streams in the Kankakee and Fox River Basins generally had lower concentrations, although the data indicate that concentrations increased in a downstream direction in these basins. These spatial patterns in nutrient concentrations correspond closely with land use in the respective basins. The elevated concentrations of ammonia and phosphorus in the urbanized Des Plaines River Basin, with respect to other sites in the study area, indicate that municipal- and industrial- waste discharges into streams of the basin increase concentrations of these nutrients in the receiving streams. In contrast, nitrate concentrations were highest in agricultural areas. Relatively large ratios of nitrogen to phosphorus and nitrate to ammonia are characteristic of agricultural drainage. On the other hand, urban tributaries were characterized by

  14. Feedbacks between bivalve density, flow, and suspended sediment concentration on patch stable states.

    Science.gov (United States)

    Coco, Giovanni; Thrush, Simon F; Green, Malcolm O; Hewitt, Judi E

    2006-11-01

    We explore the role of biophysical feedbacks occurring at the patch scale (spatial scale of tens of meters) that influence bivalve physiological condition and affect patch stability by developing a numerical model for the pinnid bivalve, Atrina zelandica, in cohesive sediments. Simulated feedbacks involve bivalve density, flow conditions (assumed to be primarily influenced by local water depth and peak current speed), suspended sediment concentration (evaluated through a balance between background concentration, deposition, and erosion), and changes in the physiology of Atrina derived from empirical study. The model demonstrates that high bivalve density can lead to skimming flow and to a concomitant decrease in resuspension that will affect suspended sediment concentration over the patch directly feeding back on bivalve physiology. Consequently, for a given flow and background suspended sediment load, the stability of a patch directly depends on the size and density of bivalves in the patch. Although under a range of conditions patch stability is ensured independently of bivalve density, simulations clearly indicate that sudden changes in bivalve density or suspended sediment concentration can substantially affect patch structure and lead to different stable states. The model highlights the role of interactions between organisms, flow, and broader scale environmental conditions in providing a mechanistic explanation for the patchy occurrence of benthic suspension feeders.

  15. Suspended-sediment rating curve response to urbanization and wildfire, Santa Ana River, California

    Science.gov (United States)

    Warrick, J.A.; Rubin, D.M.

    2007-01-01

    River suspended-sediment concentrations provide insights to the erosion and transport of materials from a landscape, and changes in concentrations with time may result from landscape processes or human disturbance. Here we show that suspended-sediment concentrations in the Santa Ana River, California, decreased 20-fold with respect to discharge during a 34-year period (1968−2001). These decreases cannot be attributed to changes in sampling technique or timing, nor to event or seasonal hysteresis. Annual peak and total discharge, however, reveal sixfold increases over the 34-year record, which largely explain the decreases in sediment concentration by a nonlinear dilution process. The hydrological changes were related to the widespread urbanization of the watershed, which resulted in increases in storm water discharge without detectable alteration of sediment discharge, thus reducing suspended-sediment concentrations. Periodic upland wildfire significantly increased water discharge, sediment discharge, and suspended-sediment concentrations and thus further altered the rating curve with time. Our results suggest that previous inventories of southern California sediment flux, which assume time-constant rating curves and extend these curves beyond the sampling history, may have substantially overestimated loads during the most recent decades.

  16. Plug Load Data

    Data.gov (United States)

    National Aeronautics and Space Administration — We provide MATLAB binary files (.mat) and comma separated values files of data collected from a pilot study of a plug load management system that allows for the...

  17. Monitoring of suspended sediment in South Tyrol

    Science.gov (United States)

    Nadalet, Rudi; Dinale, Roberto; Pernter, Martin; Maraldo, Luca; Peterlin, Dieter; Richter, Arnold; Comiti, Francesco

    2016-04-01

    In the context of the EU Water Framework Directive (WFD), which aims to achieve a good status of European water bodies, the Hydrographic Office of the Autonomous Province of Bolzano (Italy) extended in 2014 its institutional activities including the monitoring of suspended sediment in the river channel network. Currently, the only active monitoring station is on the Adige River at the gauging station of Ponte Adige near Bolzano (drainage area 2705 km2). The applied monitoring strategy and the data analysis concept are both based on the guidelines issued by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW). The results indicates that the temporal variability strongly differs during the investigated period (2014-2015). In addition to the analysis of precipitation and water discharge, temperature and lightning activity were also included to better understand the sediment transport dynamics observed at the station. In summer 2015, the combination of constantly high daily temperature throughout the Adige basin (which drove intense glacier melting in the headwaters) with a high frequency of convective rainfall events (90% more than in 2014, obtained through lightning detection), led to an annual mass of transported suspended sediment of 260000 t. Interestingly, this value is similar to the one estimated for 2014 (300000 t), which was characterized by very different meteorological conditions (colder and wetter summer), but with the occurrence of an important flood in August, which transported half of the annual amount. Finally, we can conclude that the adopted monitoring strategy is applicable for institutional aims in terms of costs as well as in terms of time effort. During the next years, other stations for suspended sediment monitoring are planned to be installed in the Province to cover the most important river segments.

  18. Active noise cancellation in a suspended interferometer

    CERN Document Server

    Driggers, Jennifer C; Pepper, Keenan; Adhikari, Rana

    2011-01-01

    We demonstrate feed-forward vibration isolation on a suspended Fabry-Perot interferometer using Wiener filtering and a variant of the common Least Mean Square (LMS) adaptive filter algorithm. We compare the experimental results with theoretical estimates of the cancellation efficiency. Using data from the recent LIGO Science Run, we also estimate the impact of this technique on full scale gravitational wave interferometers. In the future, we expect to use this technique to also remove acoustic, magnetic, and gravitational noise perturbations from the LIGO interferometers. This noise cancellation technique is simple enough to implement in standard laboratory environments and can be used to improve SNR for a variety of high precision experiments.

  19. Suspended-sediment concentrations, yields, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011

    Science.gov (United States)

    Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.

    2015-01-01

    Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, as well as transporting harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentration (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples were collected from 14 sites from 2007 through 2011. Analyses of these data indicated that the Zumbro River at Kellogg in southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. The single highest SSC of 1,250 mg/L was measured at the Zumbro River during the 2011 spring runoff. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis-St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been known to underrepresent the amount of suspended sediment. For this study, comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. Regression analysis indicated that 7 out of 14 sites had poor or no relation between SSC and streamflow. Only two sites, the Knife River and the Wild Rice River at Twin Valley, had strong correlations between SSC and streamflow, with coefficient of determination (R2) values of 0.82 and 0.80, respectively. In contrast, turbidity had moderate to strong

  20. Constructing a near-continuous suspended-sediment budget using acoustic instrumentation on the Rio Grande in Big Bend National Park, USA

    Science.gov (United States)

    Dean, D. J.; Topping, D. J.; Griffiths, R. E.; Sabol, T. A.; Schmidt, J. C.; Bennett, J. B.

    2013-12-01

    The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, is in disequilibrium. The river in this reach rapidly narrows during low-flow years, and widens during rare, large magnitude floods. One management strategy to improve in-channel habitat for the native ecosystem is to limit the rate and magnitude of channel narrowing during low-flow years through water releases from re-operated upstream dams. The proposed purpose of these dam re-operations is to maximize fine-sediment transport downstream, thereby limiting fine-sediment deposition and channel narrowing. This management strategy requires extensive knowledge of the quantity of fine-sediment supplied to the river channel, the predominant source areas of the supplied sediment, and the suspended-sediment transport dynamics over a range of flow magnitudes and durations. To address these issues, a near-continuous suspended-sediment monitoring program consisting of two suspended-sediment gages was established at two sites in Big Bend National Park, Texas. Suspended-sediment gages consist of two single-frequency sideways-looking acoustic-Doppler profilers that collect data at 15-minute intervals. Acoustic attenuation is used to calculate silt-and-clay concentration, and acoustic backscatter adjusted for silt-and-clay concentration is used to calculate sand concentration in two size classes. Acoustic attenuation and backscatter are calibrated using standard depth-integrated samples and cross-section-calibrated automatic pump samples. Two types of floods affect the sediment budgets of the Rio Grande in Big Bend National Park, long-duration releases from upstream dams and short-duration flash floods originating in tributaries upstream or between the gages. Initial analyses of suspended-sediment dynamics during long-duration dam releases show that dam releases have the potential to export fine sediment from the national park reach. Dam releases transported approximately 8% of the total silt

  1. An atomistic investigation of the effect of strain on frictional properties of suspended graphene

    Directory of Open Access Journals (Sweden)

    Qingshun Bai

    2016-05-01

    Full Text Available We performed molecular dynamics (MD simulations of a diamond probe scanned on a suspended graphene to reveal the effect of strain on the frictional properties of suspended graphene. The graphene was subjected to some certain strain along the scanning direction. We compared the friction coefficient obtained from different normal loads and strain. The results show that the friction coefficient can be decreased about one order of magnitude with the increase of the strain. And that can be a result of the decreased asymmetry of the contact region which is caused by strain. The synthetic effect of potential energy and the fluctuation of contact region were found to be the main reason accounting for the fluctuation of the friction force. The strain can reduce the fluctuation of the contact region and improve the stability of friction.

  2. An atomistic investigation of the effect of strain on frictional properties of suspended graphene

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Qingshun; He, Xin; Bai, Jinxuan [School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Tong, Zhen [Centre for precision technologies, University of Huddersfield, Huddersfield, HD1 3DH (United Kingdom)

    2016-05-15

    We performed molecular dynamics (MD) simulations of a diamond probe scanned on a suspended graphene to reveal the effect of strain on the frictional properties of suspended graphene. The graphene was subjected to some certain strain along the scanning direction. We compared the friction coefficient obtained from different normal loads and strain. The results show that the friction coefficient can be decreased about one order of magnitude with the increase of the strain. And that can be a result of the decreased asymmetry of the contact region which is caused by strain. The synthetic effect of potential energy and the fluctuation of contact region were found to be the main reason accounting for the fluctuation of the friction force. The strain can reduce the fluctuation of the contact region and improve the stability of friction.

  3. Plutonium removal and diurnal variations of suspended sediment concentrations in the Great Miami River

    Energy Technology Data Exchange (ETDEWEB)

    Bobula, III, C. M.; Kennedy, C. W.; Bartelt, G. E.

    1979-01-15

    Effluent release experiments previously conducted downstream of the industrial outflal at Mound Laboratory have demonstrated that /sup 238/Pu which enters the aquatic environment as dissolved waste is rapidly adsorbed by suspended solids in the effluent pulse and that the dissolved/particulate distribution of /sup 238/Pu between release events congruent to 5 x 10/sup -2/./sup 3/ Reasonable estimates of the annual transport of /sup 239/ /sup 240/Pu based upon long-term discharge and sediment loading data have been reported for a large subwatershed in the upper reaches of the Great Miami River Basin. In this report data are given which characterize the short-term variability of suspended particulate transport downriver of a canal system contaminated with /sup 238/Pu.

  4. Elastic properties of suspended multilayer WSe2

    Science.gov (United States)

    Zhang, Rui; Koutsos, Vasileios; Cheung, Rebecca

    2016-01-01

    We report the experimental determination of the elastic properties of suspended multilayer WSe2, a promising two-dimensional (2D) semiconducting material combined with high optical quality. The suspended WSe2 membranes have been fabricated by mechanical exfoliation of bulk WSe2 and transfer of the exfoliated multilayer WSe2 flakes onto SiO2/Si substrates pre-patterned with hole arrays. Then, indentation experiments have been performed on these membranes with an atomic force microscope. The results show that the 2D elastic modulus of the multilayer WSe2 membranes increases linearly while the prestress decreases linearly as the number of layers increases. The interlayer interaction in WSe2 has been observed to be strong enough to prevent the interlayer sliding during the indentation experiments. The Young's modulus of multilayer WSe2 (167.3 ± 6.7 GPa) is statistically independent of the thickness of the membranes, whose value is about two thirds of other most investigated 2D semiconducting transition metal dichalcogenides, namely, MoS2 and WS2. Moreover, the multilayer WSe2 can endure ˜12.4 GPa stress and ˜7.3% strain without fracture or mechanical degradation. The 2D WSe2 can be an attractive semiconducting material for application in flexible optoelectronic devices and nano-electromechanical systems.

  5. Method for forming suspended micromechanical structures

    Science.gov (United States)

    Fleming, James G.

    2000-01-01

    A micromachining method is disclosed for forming a suspended micromechanical structure from {111} crystalline silicon. The micromachining method is based on the use of anisotropic dry etching to define lateral features of the structure which are etched down into a {111}-silicon substrate to a first etch depth, thereby forming sidewalls of the structure. The sidewalls are then coated with a protection layer, and the substrate is dry etched to a second etch depth to define a spacing of the structure from the substrate. A selective anisotropic wet etchant (e.g. KOH, EDP, TMAH, NaOH or CsOH) is used to laterally undercut the structure between the first and second etch depths, thereby forming a substantially planar lower surface of the structure along a {111} crystal plane that is parallel to an upper surface of the structure. The lateral extent of undercutting by the wet etchant is controlled and effectively terminated by either timing the etching, by the location of angled {111}-silicon planes or by the locations of preformed etch-stops. This present method allows the formation of suspended micromechanical structures having large vertical dimensions and large masses while allowing for detailed lateral features which can be provided by dry etch definition. Additionally, the method of the present invention is compatible with the formation of electronic circuitry on the substrate.

  6. Spatially Explicit Estimates of Suspended Sediment and Bedload Transport Rates for Western Oregon and Northwestern California

    Science.gov (United States)

    O'Connor, J. E.; Wise, D. R.; Mangano, J.; Jones, K.

    2015-12-01

    Empirical analyses of suspended sediment and bedload transport gives estimates of sediment flux for western Oregon and northwestern California. The estimates of both bedload and suspended load are from regression models relating measured annual sediment yield to geologic, physiographic, and climatic properties of contributing basins. The best models include generalized geology and either slope or precipitation. The best-fit suspended-sediment model is based on basin geology, precipitation, and area of recent wildfire. It explains 65% of the variance for 68 suspended sediment measurement sites within the model area. Predicted suspended sediment yields range from no yield from the High Cascades geologic province to 200 tonnes/ km2-yr in the northern Oregon Coast Range and 1000 tonnes/km2-yr in recently burned areas of the northern Klamath terrain. Bed-material yield is similarly estimated from a regression model based on 22 sites of measured bed-material transport, mostly from reservoir accumulation analyses but also from several bedload measurement programs. The resulting best-fit regression is based on basin slope and the presence/absence of the Klamath geologic terrane. For the Klamath terrane, bed-material yield is twice that of the other geologic provinces. This model explains more than 80% of the variance of the better-quality measurements. Predicted bed-material yields range up to 350 tonnes/ km2-yr in steep areas of the Klamath terrane. Applying these regressions to small individual watersheds (mean size; 66 km2 for bed-material; 3 km2 for suspended sediment) and cumulating totals down the hydrologic network (but also decreasing the bed-material flux by experimentally determined attrition rates) gives spatially explicit estimates of both bed-material and suspended sediment flux. This enables assessment of several management issues, including the effects of dams on bedload transport, instream gravel mining, habitat formation processes, and water-quality. The

  7. A Spatially Distributed Conceptual Model for Estimating Suspended Sediment Yield in Alpine catchments

    Science.gov (United States)

    Costa, Anna; Molnar, Peter; Anghileri, Daniela

    2017-04-01

    Suspended sediment is associated with nutrient and contaminant transport in water courses. Estimating suspended sediment load is relevant for water-quality assessment, recreational activities, reservoir sedimentation issues, and ecological habitat assessment. Suspended sediment concentration (SSC) along channels is usually reproduced by suspended sediment rating curves, which relate SSC to discharge with a power law equation. Large uncertainty characterizes rating curves based only on discharge, because sediment supply is not explicitly accounted for. The aim of this work is to develop a source-oriented formulation of suspended sediment dynamics and to estimate suspended sediment yield at the outlet of a large Alpine catchment (upper Rhône basin, Switzerland). We propose a novel modelling approach for suspended sediment which accounts for sediment supply by taking into account the variety of sediment sources in an Alpine environment, i.e. the spatial location of sediment sources (e.g. distance from the outlet and lithology) and the different processes of sediment production and transport (e.g. by rainfall, overland flow, snowmelt). Four main sediment sources, typical of Alpine environments, are included in our model: glacial erosion, hillslope erosion, channel erosion and erosion by mass wasting processes. The predictive model is based on gridded datasets of precipitation and air temperature which drive spatially distributed degree-day models to simulate snowmelt and ice-melt, and determine erosive rainfall. A mass balance at the grid scale determines daily runoff. Each cell belongs to a different sediment source (e.g. hillslope, channel, glacier cell). The amount of sediment entrained and transported in suspension is simulated through non-linear functions of runoff, specific for sediment production and transport processes occurring at the grid scale (e.g. rainfall erosion, snowmelt-driven overland flow). Erodibility factors identify different lithological units

  8. Environmentally-suspended sediment production of the Nasia River ...

    African Journals Online (AJOL)

    The study assessed the level of suspended sediment produced in the Nasia River Basin. Hydrological and meteorological data and water samples were used for the study. Average suspended sediment yield (33 years) in the basin was 19.90 t/km2/yr. With mean annual runoff of 439.13m3/s, 322.43 t/yr suspended sediment ...

  9. The influence of a semi-arid sub-catchment on suspended sediments in the Mara River, Kenya.

    Science.gov (United States)

    Dutton, Christopher L; Subalusky, Amanda L; Anisfeld, Shimon C; Njoroge, Laban; Rosi, Emma J; Post, David M

    2018-01-01

    The Mara River Basin in East Africa is a trans-boundary basin of international significance experiencing excessive levels of sediment loads. Sediment levels in this river are extremely high (turbidities as high as 6,000 NTU) and appear to be increasing over time. Large wildlife populations, unregulated livestock grazing, and agricultural land conversion are all potential factors increasing sediment loads in the semi-arid portion of the basin. The basin is well-known for its annual wildebeest (Connochaetes taurinus) migration of approximately 1.3 million individuals, but it also has a growing population of hippopotami (Hippopotamus amphibius), which reside within the river and may contribute to the flux of suspended sediments. We used in situ pressure transducers and turbidity sensors to quantify the sediment flux at two sites for the Mara River and investigate the origin of riverine suspended sediment. We found that the combined Middle Mara-Talek catchment, a relatively flat but semi-arid region with large populations of wildlife and domestic cattle, is responsible for 2/3 of the sediment flux. The sediment yield from the combined Middle Mara-Talek catchment is approximately the same as the headwaters, despite receiving less rainfall. There was high monthly variability in suspended sediment fluxes. Although hippopotamus pools are not a major source of suspended sediments under baseflow, they do contribute to short-term variability in suspended sediments. This research identified sources of suspended sediments in the Mara River and important regions of the catchment to target for conservation, and suggests hippopotami may influence riverine sediment dynamics.

  10. Near bed suspended sediment flux by single turbulent events

    Science.gov (United States)

    Amirshahi, Seyed Mohammad; Kwoll, Eva; Winter, Christian

    2018-01-01

    The role of small scale single turbulent events in the vertical mixing of near bed suspended sediments was explored in a shallow shelf sea environment. High frequency velocity and suspended sediment concentration (SSC; calibrated from the backscatter intensity) were collected using an Acoustic Doppler Velocimeter (ADV). Using quadrant analysis, the despiked velocity time series was divided into turbulent events and small background fluctuations. Reynolds stress and Turbulent Kinetic Energy (TKE) calculated from all velocity samples, were compared to the same turbulent statistics calculated only from velocity samples classified as turbulent events (Reevents and TKEevents). The comparison showed that Reevents and TKEevents was increased 3 and 1.6 times, respectively, when small background fluctuations were removed and that the correlation with SSC for TKE could be improved through removal of the latter. The correlation between instantaneous vertical turbulent flux (w ‧) and SSC fluctuations (SSC ‧) exhibits a tidal pattern with the maximum correlation at peak ebb and flood currents, when strong turbulent events appear. Individual turbulent events were characterized by type, strength, duration and length. Cumulative vertical turbulent sediment fluxes and average SSC associated with individual turbulent events were calculated. Over the tidal cycle, ejections and sweeps were the most dominant events, transporting 50% and 36% of the cumulative vertical turbulent event sediment flux, respectively. Although the contribution of outward interactions to the vertical turbulent event sediment flux was low (11%), single outward interaction events were capable of inducing similar SSC ‧ as sweep events. The results suggest that on time scales of tens of minutes to hours, TKE may be appropriate to quantify turbulence in sediment transport studies, but that event characteristics, particular the upward turbulent flux need to be accounted for when considering sediment transport

  11. Design consideration for magnetically suspended flywheel systems

    Science.gov (United States)

    Anand, D.; Kirk, J. A.; Frommer, D. A.

    1985-01-01

    Consideration is given to the design, fabrication, and testing of a magnetically suspended flywheel system for energy storage applications in space. The device is the prototype of a system combining passive suspension of the flywheel plate by samarium cobalt magnets and active control in the radial direction using eight separate magnetic coils. The bearing assembly was machined from a nickel-iron alloy, and the machine parts are all hydrogen annealed. Slots in the magnetic plate allow four independent quadrants for control. The motor/generator component of the system is a brushless dc-permanent magnetic/ironless engine using electronic communication. The system has been tested at over 2500 rpm with satisfactory results. The system characteristics of the flywheel for application in low earth orbit (LEO) are given in a table.

  12. Organics and Suspended Solids Removal from Hospital

    Directory of Open Access Journals (Sweden)

    Fakhri Y. Hmood

    2013-05-01

    Full Text Available The Sequencing Batch Reactor (SBR method is used for treating samples of waste water taken from hospitals in Mosul. Many run periods are used (6-24 hours for             6 months. It is found that the organics and suspended solids removal increase with increasing the period of run, it is in the range ( 96-82 % and ( 100-95 % respectively, while the pH values are nearly neutral (7.05 to 7.5.     BOD5 and SS concentrations of the effluent are within the limits of Iraqi standards,  40:30 mg/l respectively. Hence, SBR method could be used for treating hospitals, small factories and some  residential sectors waste waters.  

  13. Batch fabrication of nanotubes suspended between microelectrodes

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Stöckli, T.; Knapp, H. F.

    2007-01-01

    We report a fabrication method, which uses standard UV-lithography to pattern the catalyst for the chemical vapour deposition(CVD) of suspended double clamped single walled carbon nanotubes. By using an aqueous solution of Fe(NO3)3 the patterning of the catalyst material onto microelectrodes can...... be done with a simple lift-off process with standard photolithographic resist. An applied electric field is sustained between the microelectrodes during CVD to guide the nanotube growth. Comparison with simulations shows that the location and the orientation of the grown carbon nanotubes (CNT) correspond...... to the regions of maximum electric field, enabling accurate positioning of a nanotube by controlling the shape of the microelectrodes. The CNT bridges are deflected tens of nm when a DC voltage is applied between the nanotube and a gate microelectrode indicating that the clamping through the catalyst particles...

  14. Copper, lead and cadmium loads and behavior in urban stormwater runoff in Curitiba, Brazil

    Directory of Open Access Journals (Sweden)

    Prestes Ellen C.

    2006-01-01

    Full Text Available We investigate the presence and behavior of Cu, Pb, and Cd in runoff waters from a residential area located in the city of Curitiba, Brazil. Samples were collected in twenty-one stormwater events in an intermediate traffic way located in the Bacacheri watershed. Metal concentrations were similar to range values compiled worldwide and followed the order: Pb>Cu>>Cd. Unit loads were estimated to the watershed, which cover an area of 30 km², revealing values of 1520, 950, 25 kg for Pb, Cu, and Cd, respectively. Among the three metals, lead showed the greatest affinity for the suspended solids (82% followed by Cd (66% and Cu (48%. Meanwhile, an association of the metals with the organic matter in the dissolved phase, following the order Cu>Pb>Cd. Metal loads and behavior in urban runoff also depends on factors such as the first flush and the dry period preceding a storm event.

  15. Present and Reference Concentrations and Yields of Suspended Sediment in Streams in the Great Lakes Region and Adjacent Areas

    Science.gov (United States)

    Robertson, Dale M.; Saad, David A.; Heisey, Dennis M.

    2006-01-01

    In-stream suspended sediment and siltation and downstream sedimentation are common problems in surface waters throughout the United States. The most effective way to improve surface waters impaired by sediments is to reduce the contributions from human activities rather than try to reduce loadings from natural sources. Total suspended sediment/solids (TSS) concentration data were obtained from 964 streams in the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River Basins from 1951 to 2002. These data were used to estimate median concentrations, loads, yields, and volumetrically (flow) weighted (VW) concentrations where streamflow data were available. SPAtial Regression-Tree Analysis (SPARTA) was applied to land-use-adjusted (residualized) TSS data and environmental-characteristic data to determine the natural factors that best described the distribution of median and VW TSS concentrations and yields and to delineate zones with similar natural factors affecting TSS, enabling reference or natural concentrations and yields to be estimated. Soil properties (clay and organic-matter content, erodibility, and permeability), basin slope, and land use (percentage of agriculture) were the factors most strongly related to the distribution of median and VW TSS concentrations. TSS yields were most strongly related to amount of precipitation and the resulting runoff, and secondarily to the factors related to high TSS concentrations. Reference median TSS concentrations ranged from 5 to 26 milligrams per liter (mg/L), reference median annual VW TSS concentrations ranged from 10 to 168 mg/L, and reference TSS yields ranged from about 980 to 90,000 kilograms per square kilometer per year. Independent streams (streams with no overlapping drainage areas) with TSS data were ranked by how much their water quality exceeded reference concentrations and yields. Most streams exceeding reference conditions were in the central part of the study area, where agricultural activities

  16. Vertical Distribution of Suspended Sediment under Steady Flow: Existing Theories and Fractional Derivative Model

    Directory of Open Access Journals (Sweden)

    Shiqian Nie

    2017-01-01

    Full Text Available The fractional advection-diffusion equation (fADE model is a new approach to describe the vertical distribution of suspended sediment concentration in steady turbulent flow. However, the advantages and parameter definition of the fADE model in describing the sediment suspension distribution are still unclear. To address this knowledge gap, this study first reviews seven models, including the fADE model, for the vertical distribution of suspended sediment concentration in steady turbulent flow. The fADE model, among others, describes both Fickian and non-Fickian diffusive characteristics of suspended sediment, while the other six models assume that the vertical diffusion of suspended sediment follows Fick’s first law. Second, this study explores the sensitivity of the fractional index of the fADE model to the variation of particle sizes and sediment settling velocities, based on experimental data collected from the literatures. Finally, empirical formulas are developed to relate the fractional derivative order to particle size and sediment settling velocity. These formulas offer river engineers a substitutive way to estimate the fractional derivative order in the fADE model.

  17. How much suspended particulate matter enters long-term in-channel storage?

    Science.gov (United States)

    Dietrich, Stephan; Kleisinger, Carmen; Kehl, Nora; Schubert, Birgit; Hillebrand, Gudrun

    2017-04-01

    The route of suspended particulate matter (SPM) downstream rivers strongly depends on discharge conditions and involves transport times and periods with resting times in deposits e.g. at areas with low-flow conditions near the channel bed. It is, however, difficult to estimate the contribution of SPM on the bed load. In this study, particle-bound polychlorinated biphenyls (PCB), which were released by an incident in the Elbe river (Central Europe) in spring 2015, could be used as unique tracer for transport pathways of SPM along the whole river stretch (over 700 km length), including low mountain ranges, lowlands, and the estuary. In 2015 the Elbe River was characterized by low-discharge conditions. Thus, the export of SPM on flood plains was strongly limited. The incident was monitored by concentration measurements of seven indicator PCB congeners along the inland part of the Elbe River as well as in the Elbe estuary. Data from ten monitoring stations (settling tanks) are considered. The total PCB load is calculated for all stations on the basis of monthly contaminant concentrations and daily suspended sediment concentrations. Monte-Carlo simulations assess the uncertainties of the calculated load. It is shown that the ratio of high versus low chlorinated PCB congeners is a suitable tracer to distinguish the PCB load of the incident from the long-term background signal (hereafter PCB6 ratio). We demonstrate that both the load of PCB as well as its chemical fingerprint allows the estimation of transport durations for the transport processes involved. Only a little part of the suspension has been transported via wash load. The PCB6 ratio is used to estimate mean transport velocities of the wash load fraction. A direct transport of wash load via the mean flow velocity of the water was not observed. Shortly after the incident, the PCB6 ratio was monitored 257 km downstream of the incident site in April 2015, in May first occurrence was monitored 514 km downstream of

  18. Spatial and temporal patterns of turbidity, sediment concentration and load across nested scales in an urban watershed

    Science.gov (United States)

    Kemper, J. T.; Welty, C.; Miller, A. J.

    2016-12-01

    In a highly regulated area such as the Chesapeake Bay watershed, suspended sediment is a matter of primary concern. However, there are few continuous sediment-concentration records available to quantify urban sediment loads. Near real-time turbidity and discharge data have been collected continuously for more than three years at six stream gages representing three nested watershed scales (1-2 sq km, 5-6 sq km, 14 sq km) in the highly impervious Dead Run watershed, located in Baltimore County, MD. Suspended sediment point samples have been collected for multiple storm events at five of the six sites, to establish provisional relationships between turbidity and suspended sediment concentrations. Using these calculated relationships and USGS discharge data, we can quantify sediment loads at each station. Turbidity-discharge relationships vary both spatially and temporally, highlighting the extreme heterogeneity of an urban watershed. Spatially, relationships change from headwaters to mouth, potentially suggesting a variation in sediment sources. Temporally, relationships change both seasonally and annually. The lowest turbidity values are consistently seen in the fall, while values in winter, spring, and summer display a high inter-annual variability. Sediment loads and yields calculated for four representative storms are compared across nested watershed scales to assess evidence for sources or sinks at different locations within the drainage network. Yields at the mouth of the watershed (DRKR) for large storms were higher than an area-weighted average of the two contributing sites (DR3, DR4), potentially suggesting additional source areas of sediment within the watershed. This highlights the ability of near real-time data to assist in developing more effective approaches in mitigating sediment transport by helping to identifying consistent trends, locations of hot spots, and patterns of sediment arrival.

  19. Simulation of suspended sediment transport initialized with satellite derived suspended sediment concentrations

    Science.gov (United States)

    Ramakrishnan, Ratheesh; Rajawat, A. S.

    2012-10-01

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are realized with respect to the sediment size distribution and the bottom bed materials observed in the Gulf. Simulated SSCs are compared with alternate OCM derived SSC. The results are observed to be impetus where the model is able to generate the spatial dynamics of the sediment concentrations. Sediment dynamics like deposition, erosion and dispersion are explained with the simulated tidal currents and OCM derived sediment concentrations. Tidal range is observed as the important physical factor controlling the deposition and resuspension of sediments within the Gulf. From the simulation studies; maximum residual current velocities, tidal fronts and high turbulent zones are found to characterise the islands and shoals within the Gulf, which results in high sediment concentrations in those regions. Remarkable variability in the bathymetry of the Gulf, different bed materials and varying tidal conditions induces several circulation patterns and turbulence creating the unique suspended sediment concentration pattern in the Gulf.

  20. A suspended sediment yield predictive equation for river basins in ...

    African Journals Online (AJOL)

    An empirical equation that can be used for estimating the suspended sediment yields of river drainage basins without sediment data has been established for basins in the sub-tropical forest Southwestern river basin system of Ghana. The power law equation relates mean annual specific suspended sediment yield (t km-2 ...

  1. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud. Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are ...

  2. Energy values of suspended detritus in Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Royan, J.P.; Sumitra-Vijayaraghavan

    Energy content of suspended detritus was determined in Andaman Sea waters during April-May 1988. The caloric content of suspended detritus ranged from 987 to 7040 cal. per gram dry wt with an average value of 5530 cal. per gram dry wt. The results...

  3. A wave-resolving model for nearshore suspended sediment transport

    Science.gov (United States)

    Ma, Gangfeng; Chou, Yi-Ju; Shi, Fengyan

    2014-05-01

    This paper presents a wave-resolving sediment transport model, which is capable of simulating sediment suspension in the field-scale surf zone. The surf zone hydrodynamics is modeled by the non-hydrostatic model NHWAVE (Ma et al., 2012). The turbulent flow and suspended sediment are simulated in a coupled manner. Three effects of suspended sediment on turbulent flow field are considered: (1) baroclinic forcing effect; (2) turbulence damping effect and (3) bottom boundary layer effect. Through the validation with the laboratory measurements of suspended sediment under nonbreaking skewed waves and surfzone breaking waves, we demonstrate that the model can reasonably predict wave-averaged sediment profiles. The model is then utilized to simulate a rip current field experiment (RCEX) and nearshore suspended sediment transport. The offshore sediment transport by rip currents is captured by the model. The effects of suspended sediment on self-suspension are also investigated. The turbulence damping and bottom boundary layer effects are significant on sediment suspension. The suspended sediment creates a stably stratified water column, damping fluid turbulence and reducing turbulent diffusivity. The suspension of sediment also produces a stably stratified bottom boundary layer. Thus, the drag coefficient and bottom shear stress are reduced, causing less sediment pickup from the bottom. The cross-shore suspended sediment flux is analyzed as well. The mean Eulerian suspended sediment flux is shoreward outside the surf zone, while it is seaward in the surf zone.

  4. Evaluation of the suspending properties of Cola acuminata gum on ...

    African Journals Online (AJOL)

    Many natural gums are employed as suspending agents in the formulation of pharmaceutical suspensions. The search to develop locally available natural gum from apparently a waste product as an alternative suspending agent stimulated the interest in this present study. Cola acuminata gum (CAG) extracted from Cola ...

  5. 40 CFR 230.21 - Suspended particulates/turbidity.

    Science.gov (United States)

    2010-07-01

    ... time. These new levels may reduce light penetration and lower the rate of photosynthesis and the... suspended particulates persist. The biological and the chemical content of the suspended material may react with the dissolved oxygen in the water, which can result in oxygen depletion. Toxic metals and organics...

  6. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are ...

  7. Evaluation of the suspending property of grewia gum in ...

    African Journals Online (AJOL)

    The suspending property of grewia gum in sulphadimidine suspension was evaluated. The gum was extracted by maceration, filtration, precipitation and drying techniques. It was used at 0.3 to 1% w/v as a suspending agent for sulphadimidine. Sodiumcarboxymethylcellulose (SCMC) and tragacanth were used as basis for ...

  8. Evaluation of the suspending properties of Adansonia digitata gum ...

    African Journals Online (AJOL)

    Sedimentation volume and rate, rheology, and ease of redispersion were employed as evaluation parameters. The results showed that both hot and cold water extracts of the gum used at 2-3 % w/v produced a better suspending property than 4 % w/v Compound Tragacanth gum. The suspending ability of the gums was in ...

  9. Evaluation of the Suspending Property of Grewia Gum in ...

    African Journals Online (AJOL)

    The suspending property of grewia gum in metronidazole suspension was evaluated. The gum was extracted by maceration, filtration, precipitation and drying techniques. It was used at 0.3 to 1% w/v as a suspending agent for metronidazole. Sodiumcarboxymethylcellulose (SCMC) and tragacanth were used as basis for ...

  10. Seasonal trends of benzo(apyrene in suspended particulate matter in urban areas of Belgrade, Serbia

    Directory of Open Access Journals (Sweden)

    Snežana Matić-Besarabić

    2010-09-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs were identified to be one of the major toxic air pollutants in urban environment. PAHs are mostly formed during incomplete combustion or pyrolysis of organic material. According to Serbian National Legislation, benzo(apyrene (BaP concentration in total suspended particles (TSP in ambient air in the Belgrade metropolitan area has been determined in the last ten years, as a part of a local air pollution monitoring program performed by the Public Health Institute of Belgrade and funded by Belgrade’s Municipality. Air samples for analysis of BaP in suspended particleshave been collected (as 24 h sample once per month at selected onitoring sites within the municipal air quality monitoring network. At the beginning, according to National Regulation, all samples were taken as total suspended particles (TSP. Since mid-2008, the procedure of sampling methodology was harmonized with EU requirements and solid fraction PM10 has been collected and analyzed using GC/MS. In this study, we have analyzed results of TSP collected between 2005 and 2008. Looking through the results obtained during the period of a whole year, it can be noticed that concentrations of BaP were much higher during winter season at almost all measuring sites.

  11. Sediment load and distribution in the lower Skagit River, Skagit County, Washington

    Science.gov (United States)

    Curran, Christopher A.; Grossman, Eric E.; Mastin, Mark C.; Huffman, Raegan L.

    2016-08-17

    The Skagit River delivers about 40 percent of all fluvial sediment that enters Puget Sound, influencing flood hazards in the Skagit lowlands, critically important estuarine habitat in the delta, and some of the most diverse and productive agriculture in western Washington. A total of 175 measurements of suspended-sediment load, made routinely from 1974 to 1993, and sporadically from 2006 to 2009, were used to develop and evaluate regression models of sediment transport (also known as “sediment-rating curves”) for estimating suspended-sediment load as a function of river discharge. Using a flow-range model and 75 years of daily discharge record (acquired from 1941 to 2015), the mean annual suspended-sediment load for the Skagit River near Mount Vernon, Washington, was estimated to be 2.5 teragrams (Tg, where 1 Tg = 1 million metric tons). The seasonal model indicates that 74 percent of the total annual suspended‑sediment load is delivered to Puget Sound during the winter storm season (from October through March), but also indicates that discharge is a poor surrogate for suspended‑sediment concentration (SSC) during the summer low-flow season. Sediment-rating curves developed for different time periods revealed that the regression model slope of the SSC-discharge relation increased 66 percent between the periods of 1974–76 and 2006–09 when suspended-sediment samples were collected, implying that changes in sediment supply, channel hydraulics, and (or) basin hydrology occurred between the two time intervals. In the relatively wet water year 2007 (October 1, 2006, through September 30, 2007), an automated sampler was used to collect daily samples of suspended sediment from which an annual load of 4.5 Tg was calculated, dominated by a single large flood event that contributed 1.8 Tg, or 40 percent of the total. In comparison, the annual load calculated for water year 2007 using the preferred flow-range model was 4.8 Tg (+6.7 percent), in close agreement with

  12. Investigating suspended sediment dynamics in contrasting agricultural catchments using ex situ turbidity-based suspended sediment monitoring

    Science.gov (United States)

    Sherriff, S. C.; Rowan, J. S.; Melland, A. R.; Jordan, P.; Fenton, O.; hUallachain, D. O.

    2015-08-01

    Soil erosion and suspended sediment (SS) pose risks to chemical and ecological water quality. Agricultural activities may accelerate erosional fluxes from bare, poached or compacted soils, and enhance connectivity through modified channels and artificial drainage networks. Storm-event fluxes dominate SS transport in agricultural catchments; therefore, high temporal-resolution monitoring approaches are required, but can be expensive and technically challenging. Here, the performance of in situ turbidity sensors, conventionally installed submerged at the river bankside, is compared with installations where river water is delivered to sensors ex situ, i.e. within instrument kiosks on the riverbank, at two experimental catchments (Grassland B and Arable B). The in situ and ex situ installations gave comparable results when calibrated against storm-period, depth-integrated SS data, with total loads at Grassland B estimated at 12 800 and 15 400 t, and 22 600 and 24 900 t at Arable B, respectively. The absence of spurious turbidity readings relating to bankside debris around the in situ sensor and its greater security make the ex situ sensor more robust. The ex situ approach was then used to characterise SS dynamics and fluxes in five intensively managed agricultural catchments in Ireland which feature a range of landscape characteristics and land use pressures. Average annual suspended sediment concentration (SSC) was below the Freshwater Fish Directive (78/659/EEC) guideline of 25 mg L-1, and the continuous hourly record demonstrated that exceedance occurred less than 12 % of the observation year. Soil drainage class and proportion of arable land were key controls determining flux rates, but all catchments reported a high degree of inter-annual variability associated with variable precipitation patterns compared to the long-term average. Poorly drained soils had greater sensitivity to runoff and soil erosion, particularly in catchments with periods of bare soils. Well

  13. Numerical modelling of hydro-morphological processes dominated by fine suspended sediment in a stormwater pond

    Science.gov (United States)

    Guan, Mingfu; Ahilan, Sangaralingam; Yu, Dapeng; Peng, Yong; Wright, Nigel

    2018-01-01

    Fine sediment plays crucial and multiple roles in the hydrological, ecological and geomorphological functioning of river systems. This study employs a two-dimensional (2D) numerical model to track the hydro-morphological processes dominated by fine suspended sediment, including the prediction of sediment concentration in flow bodies, and erosion and deposition caused by sediment transport. The model is governed by 2D full shallow water equations with which an advection-diffusion equation for fine sediment is coupled. Bed erosion and sedimentation are updated by a bed deformation model based on local sediment entrainment and settling flux in flow bodies. The model is initially validated with the three laboratory-scale experimental events where suspended load plays a dominant role. Satisfactory simulation results confirm the model's capability in capturing hydro-morphodynamic processes dominated by fine suspended sediment at laboratory-scale. Applications to sedimentation in a stormwater pond are conducted to develop the process-based understanding of fine sediment dynamics over a variety of flow conditions. Urban flows with 5-year, 30-year and 100-year return period and the extreme flood event in 2012 are simulated. The modelled results deliver a step change in understanding fine sediment dynamics in stormwater ponds. The model is capable of quantitatively simulating and qualitatively assessing the performance of a stormwater pond in managing urban water quantity and quality.

  14. Writing and functionalisation of suspended DNA nanowires on superhydrophobic pillar arrays

    KAUST Repository

    Miele, Ermanno

    2014-08-08

    Nanowire arrays and networks with precisely controlled patterns are very interesting for innovative device concepts in mesoscopic physics. In particular, DNA templates have proven to be versatile for the fabrication of complex structures that obtained functionality via combinations with other materials, for example by functionalisation with molecules or nanoparticles, or by coating with metals. Here, the controlled motion of the a three-phase contact line (TCL) of DNA-loaded drops on superhydrophobic substrates is used to fabricate suspended nanowire arrays. In particular, the deposition of DNA wires is imaged in situ, and different patterns are obtained on hexagonal pillar arrays by controlling the TCL velocity and direction. Robust conductive wires and networks are achieved by coating the wires with a thin layer of gold, and as proof of concept conductivity measurements are performed on single suspended wires. The plastic material of the superhydrophobic pillars ensures electrical isolation from the substrate. The more general versatility of these suspended nanowire networks as functional templates is outlined by fabricating hybrid organic-metal-semiconductor nanowires by growing ZnO nanocrystals onto the metal-coated nanowires.

  15. A combined use of acoustic and optical devices to investigate suspended sediment in rivers

    Science.gov (United States)

    Guerrero, Massimo; Rüther, Nils; Haun, Stefan; Baranya, Sandor

    2017-04-01

    The use of acoustic and optic devices has become more and more common for estimating suspended sediment loads in rivers. The echo intensity levels (EIL) recorded by means of an Acoustic Doppler Current Profiler (ADCP) have been applied in different methods, which provided relationships between scattering particles features derived from samples (i.e., concentration and grain size) and corresponding backscattering strength and sound attenuation. At the same time, the laser diffraction was applied by an in-stream sampler (LISST-SL) to measure suspended sediment concentration and the corresponding particle size distribution (PSD). These two techniques exhibited different limitations in terms of the measured range of concentration, sensitivity to a certain spectrum of particle sizes, and instruments deploy feasibility especially in large rivers, in a way that the use of sampled PSD by LISST-SL to validate ADCP methods may not be trivial. The aim of this study was to combine the vertical profiling of EIL by an ADCP with results from LISST-SL, eventually demonstrating the possibility of using moving ADCP measurements to detect different suspended matters along a Danube River section characterized by a small tributary junction. At the same time, this work elucidates optical to acoustic method deviations that hinders an actual validation of ADCP methods based on LISST-SL rather than with physical samplings.

  16. SDRE controller for motion design of cable-suspended robot with uncertainties and moving obstacles

    Science.gov (United States)

    Behboodi, Ahad; Salehi, Seyedmohammad

    2017-10-01

    In this paper an optimal control approach for nonlinear dynamical systems was proposed based on State Dependent Riccati Equation (SDRE) and its robustness against uncertainties is shown by simulation results. The proposed method was applied on a spatial six-cable suspended robot, which was designed to carry loads or perform different tasks in huge workspaces. Motion planning for cable-suspended robots in such a big workspace is subjected to uncertainties and obstacles. First, we emphasized the ability of SDRE to construct a systematic basis and efficient design of controller for wide variety of nonlinear dynamical systems. Then we showed how this systematic design improved the robustness of the system and facilitated the integration of motion planning techniques with the controller. In particular, obstacle avoidance technique based on artificial potential field (APF) can be easily combined with SDRE controller with efficient performance. Due to difficulties of exact solution for SDRE, an approximation method was used based on power series expansion. The efficiency and robustness of the SDRE controller was illustrated on a six-cable suspended robot with proper simulations.

  17. Writing and functionalisation of suspended DNA nanowires on superhydrophobic pillar arrays.

    Science.gov (United States)

    Miele, Ermanno; Accardo, Angelo; Falqui, Andrea; Marini, Monica; Giugni, Andrea; Leoncini, Marco; De Angelis, Francesco; Krahne, Roman; Di Fabrizio, Enzo

    2015-01-07

    Nanowire arrays and networks with precisely controlled patterns are very interesting for innovative device concepts in mesoscopic physics. In particular, DNA templates have proven to be versatile for the fabrication of complex structures that obtained functionality via combinations with other materials, for example by functionalisation with molecules or nanoparticles, or by coating with metals. Here, the controlled motion of the a three-phase contact line (TCL) of DNA-loaded drops on superhydrophobic substrates is used to fabricate suspended nanowire arrays. In particular, the deposition of DNA wires is imaged in situ, and different patterns are obtained on hexagonal pillar arrays by controlling the TCL velocity and direction. Robust conductive wires and networks are achieved by coating the wires with a thin layer of gold, and as proof of concept conductivity measurements are performed on single suspended wires. The plastic material of the superhydrophobic pillars ensures electrical isolation from the substrate. The more general versatility of these suspended nanowire networks as functional templates is outlined by fabricating hybrid organic-metal-semiconductor nanowires by growing ZnO nanocrystals onto the metal-coated nanowires. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. A preliminary assessment of the spatial sources of contemporary suspended sediment in the Ohio River basin, United States, using water quality data from the NASQAN programme in a source tracing procedure

    Science.gov (United States)

    Zhang, Y.-S.; Collins, A.L.; Horowitz, A.J.

    2012-01-01

    Reliable information on catchment scale suspended sediment sources is required to inform the design of management strategies for helping abate the numerous environmental issues associated with enhanced sediment mobilization and off-site loadings. Since sediment fingerprinting techniques avoid many of the logistical constraints associated with using more traditional indirect measurement methods at catchment scale, such approaches have been increasingly reported in the international literature and typically use data sets collected specifically for sediment source apportionment purposes. There remains scope for investigating the potential for using geochemical data sets assembled by routine monitoring programmes to fingerprint sediment provenance. In the United States, routine water quality samples are collected as part of the US Geological Survey's revised National Stream Quality Accounting Network programme. Accordingly, the geochemistry data generated from these samples over a 10-year period (1996-2006) were used as the basis for a fingerprinting exercise to assess the key tributary sub-catchment spatial sources of contemporary suspended sediment transported by the Ohio River. Uncertainty associated with the spatial source estimates was quantified using a Monte Carlo approach in conjunction with mass balance modelling. Relative frequency weighted means were used as an alternative way of summarizing the spatial source contributions, thereby avoiding the need to use confidence limits. The results should be interpreted in the context of the routine, but infrequent nature, of the suspended sediment samples used to assemble geochemistry as a basis for the sourcing exercise. Nonetheless, the study demonstrates how routine monitoring samples can be used to provide some preliminary information on sediment provenance in large drainage basins. ?? 2011 John Wiley & Sons, Ltd.

  19. Sediment fingerprinting to determine the source of suspended sediment in a southern Piedmont stream.

    Science.gov (United States)

    Mukundan, R; Radcliffe, D E; Ritchie, J C; Risse, L M; McKinley, R A

    2010-01-01

    Thousands of stream miles in the southern Piedmont region are impaired because of high levels of suspended sediment. It is unclear if the source is upland erosion from agricultural sources or bank erosion of historic sediment deposited in the flood plains between 1830 and 1930 when cotton farming was extensive. The objective of this study was to determine the source of high stream suspended sediment concentrations in a typical southern Piedmont watershed using sediment fingerprinting techniques. Twenty-one potential tracers were tested for their ability to discriminate between sources, conservative behavior, and lack of redundancy. Tracer concentrations were determined in potential sediment sources (forests, pastures, row crop fields, stream banks, and unpaved roads and construction sites), and suspended sediment samples collected from the stream and analyzed using mixing models. Results indicated that 137Cs and 15N were the best tracers to discriminate potential sediment sources in this watershed. The delta15N values showed distinct signatures in all the potential suspended sediment sources, and delta15N was a unique tracer to differentiate stream bank soil from upland subsurface soils, such as soil from construction sites, unpaved roads, ditches, and field gullies. Mixing models showed that about 60% of the stream suspended sediment originated from eroding stream banks, 23 to 30% from upland subsoil sources (e.g., construction sites and unpaved roads), and about 10 to 15% from pastures. The results may be applicable to other watersheds in the Piedmont depending on the extent of urbanization occurring in these watersheds. Better understanding of the sources of fine sediment has practical implications on the type of sediment control measures to be adopted. Investment of resources in improving water quality should consider the factors causing stream bank erosion and erosion from unpaved roads and construction sites to water quality impairment.

  20. Particle Size Characteristics of Fluvial Suspended Sediment in Proglacial Streams, King George Island, South Shetland Island

    Science.gov (United States)

    Szymczak, Ewa

    2017-12-01

    In this study, the characterization of particle size distribution of suspended sediment that is transported by streams (Ornithologist Creek, Ecology Glacier Creeks, Petrified Forest Creek, Czech Creek, Vanishing Creek, Italian Creek) in the area of the Arctowski Polish Antarctic Station is presented. During the first period of the summer season, the aforementioned streams are supplied by the melting snow fields, while later on, by thawing permafrost. The water samples were collected from the streams at monthly intervals during the Antarctic summer season (January - March) of 2016. The particle size distribution was measured in the laboratory with a LISST-25X laser diffraction particle size analyser. According to Sequoia Scientific Inc., LISST-25X can measure particle sizes (Sauter Mean Diameter) between 2.50 and 500 μm. The results of particle size measurements were analysed in relation to flow velocity (0.18–0.89 m/s), the cross-sectional parameters of the streams, suspended sediment concentration (0.06–167.22 mg/dm3) and the content of particulate organic matter (9.8–84.85%). Overall, the mean particle size ranged from 28.8 to 136 μm. The grain size of well-sorted sediments ranged from 0.076 to 0.57, with the skewness and kurtosis values varying from -0.1 to 0.4, and from 0.67 to 1.3, respectively. Based on the particle size characteristics of suspended sediment, the streams were divided into two groups. For most of the streams, the sediment was very well sorted, while fine sand and very fine sand were dominant fractions displaying symmetric and platykurtic distributions, respectively. Only in two streams, the suspended sediment consisted of silt-size grains, well or moderately well sorted, with coarse-skewness and mostly mesokurtic distribution. The C-M chart suggested that the transportation processes of suspended sediment included the suspended mode only. The grain-size distribution of suspended sediment was mainly influenced by the stream runoff

  1. Diffusion processes in freely suspended smectic films

    Science.gov (United States)

    Śliwa, I.; Zakharov, A. V.

    2017-08-01

    A molecular model describing translational diffusion in freely suspended smectic films (FSSFs) in air is proposed. This model is based on the random walk theory and allows calculation of the translational diffusion coefficient (TDC) across smectic layers (along the director). All values necessary for calculating the TDC are obtained within the generalized mean-field model considering not only anisotropic interactions between nearest neighbors of molecules forming FSSFs, but also the stabilizing effect of the smectic/air interface. The spatial inhomogeneity of order parameters over the FSSF section, arising in this case, results in the fact that the surface tension at the smectic/air interface not only suppresses thermal fluctuations in surface layers, but also completely suppresses translational diffusion of molecules from the FSSF to air. The results of calculations of dimensional translational diffusion in the bulk of the FSSF formed by 5- n-alkyl-2-(4- n-(perfluoroalkyl-metyleneoxy))pentyl molecules during its thinning show that the TDC monotonically increases as the smectic film is thinned.

  2. Spatial distribution of suspended particulate matter in the Mandovi and Zuari estuaries: inferences on the estuarine turbidity maximum

    Digital Repository Service at National Institute of Oceanography (India)

    Suja, S.; Kessarkar, P.M; Shynu, R.; Rao, V.P.; Fernandes, L.L.

    The present study estimate the suspended particulate matter in the Mandovi and Zuari estuaries. samples were collected from the Mandovi (M0A–M9) and Zuari (Z0–Z8) estuaries and Cumbarjua canal (C0–C3).The spatial distribution of SPM in the Ma...

  3. 45 CFR 2506.5 - If a debt is not excluded from these regulations, may it be compromised, suspended, terminated...

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false If a debt is not excluded from these regulations, may it be compromised, suspended, terminated, or waived? 2506.5 Section 2506.5 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE COLLECTION...

  4. Automatic real-time control of suspended sediment based upon high frequency in situ measurements of nephelometric turbidity

    Science.gov (United States)

    Jack Lewis; Rand Eads

    1998-01-01

    Abstract - For estimating suspended sediment concentration (SSC) in rivers, turbidity is potentially a much better predictor than water discharge. Since about 1990, it has been feasible to automatically collect high frequency turbidity data at remote sites using battery-powered turbidity probes that are properly mounted in the river or stream. With sensors calibrated...

  5. Mercury concentrations and loads in a large river system tributary to San Francisco Bay, California, USA

    Science.gov (United States)

    David, N.; McKee, L.J.; Black, F.J.; Flegal, A.R.; Conaway, C.H.; Schoellhamer, D.H.; Ganju, N.K.

    2009-01-01

    In order to estimate total mercury (HgT) loads entering San Francisco Bay, USA, via the Sacramento-San Joaquin River system, unfiltered water samples were collected between January 2002 and January 2006 during high flow events and analyzed for HgT. Unfiltered HgT concentrations ranged from 3.2 to 75 ng/L and showed a strong correlation (r2 = 0.8, p < 0.001, n = 78) to suspended sediment concentrations (SSC). During infrequent large floods, HgT concentrations relative to SSC were approximately twice as high as observed during smaller floods. This difference indicates the transport of more Hg-contaminated particles during high discharge events. Daily HgT loads in the Sacramento-San Joaquin River at Mallard Island ranged from below the limit of detection to 35 kg. Annual HgT loads varied from 61 ?? 22 kg (n = 5) in water year (WY) 2002 to 470 ?? 170 kg (n = 25) in WY 2006. The data collected will assist in understanding the long-term recovery of San Francisco Bay from Hg contamination and in implementing the Hg total maximum daily load, the long-term cleanup plan for Hg in the Bay. ?? 2009 SETAC.

  6. Cyclone Driven Sediment Loads in a Tropical Mega-River.

    Science.gov (United States)

    Darby, Stephen; Leyland, Julian; Hackney, Christopher; Heasley, Eleanore; Kummu, Matti; Lauri, Hannu; Parsons, Daniel; Nicholas, Andrew; Aalto, Rolf; Best, Jim

    2015-04-01

    Understanding the links between environmental change and sediment transport in the mega-rivers that dominate the flux of terrestrial sediment to their deltas and oceans remains a major challenge. Many large river systems display significant seasonality in flow regime, which is affected to a greater or lesser degree by the influence of large tropical storms, which act to increase their variability and thus drive uncertainty in predicting the impacts associated with changes in future flow regimes. Here we demonstrate the significance of tropical storms in driving sediment flux from one of the world's largest rivers, the Mekong, to its delta. Data was collected at Kratie, Cambodia; this being the site of the Mekong's final reliable flow gauging station before the Mekong delta. Suspended sediment fluxes were estimated by calibrating acoustic backscatter returns from an acoustic Doppler current profiler to observed suspended sediment concentrations (SSCs) across a monsoon cycle. The retrieved SSCs were combined with flow velocity estimates to recover the sediment flux. These estimates of flux were then used to build sediment rating curves to predict suspended flux as a function of flow discharge. A hydrological model, VMod, was then used to estimate daily discharge values for the same historical period, but for a scenario in which the effects of tropical storms on the flow regime are isolated. This was achieved by forcing the hydrological model with daily precipitation values that account for precipitation anomalies associated with observed tropical storms. The difference in cumulative sediment transport estimated by combining the two flow discharge scenarios with the constructed sediment rating curves allowed the contribution of tropical storms to the Lower Mekong's suspended sediment transport regime to be isolated. It was found that sediment loads in the Mekong River attenuate downstream from approximately 120 MT in Laos and Thailand to ~80-90 MT in the alluvial

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

    Science.gov (United States)

    Mason, J.; Mohrig, D. C.

    2015-12-01

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

  8. The role of suspension events in cross-shore and longshore suspended sediment transport in the surf zone

    Science.gov (United States)

    Jaffe, Bruce E.

    2015-01-01

    Suspension of sand in the surf zone is intermittent. Especially striking in a time series of concentration are periods of intense suspension, suspension events, when the water column suspended sediment concentration is an order of magnitude greater than the mean concentration. The prevalence, timing, and contribution of suspension events to cross-shore and longshore suspended sediment transport are explored using field data collected in the inner half of the surf zone during a large storm at Duck, NC. Suspension events are defined as periods when the concentration is above a threshold. Events tended to occur during onshore flow under the wave crest, resulting in an onshore contribution to the suspended sediment transport. Even though large events occurred less than 10 percent of the total time, at some locations onshore transport associated with suspension events was greater than mean-current driven offshore-directed transport during non-event periods, causing the net suspended sediment transport to be onshore. Events and fluctuations in longshore velocity were not correlated. However, events did increase the longshore suspended sediment transport by approximately the amount they increase the mean concentration, which can be up to 35%. Because of the lack of correlation, the longshore suspended sediment transport can be modeled without considering the details of the intensity and time of events as the vertical integration of the product of the time-averaged longshore velocity and an event-augmented time-averaged concentration. However, to accurately model cross-shore suspended sediment transport, the timing and intensity of suspension events must be reproduced.

  9. Influence of particulates on phosphorus loading exported from farm drainage during a storm event in the Everglades Agricultural Area

    Science.gov (United States)

    Bhadha, J. H.; Lang, T. A.; Daroub, S. H.

    2015-12-01

    The purpose of this study was to evaluate the influence of particulates on P loading captured during a single storm event. The Everglades Agricultural Area of Florida comprises 280,000 hectares of organic soil farmland artificially drained by ditches, canals and pumps. Phosphorus (P)-enriched suspended particulates in canals are susceptible to transport and can contribute significantly to the overall P loads in drainage water. A settling tank experiment was conducted to capture particulates during tropical storm Isaac in 2012 from three farms approximately 2.4 to 3.6 km2 in size. Farm canal discharge water was collected in a series of two 200 liter settling tanks over a seven-day drainage period, during tropical storm Isaac. Water from the settling tanks was siphoned through Imhoff settling cones, where the particulates were allowed to settle and collected for P-fractionation analyses, and compared to intact sediment cores collected from the bottom of the canals. The discharged particulates contained higher organic matter content (OM), total P, and labile P fractions compared to the canal bottom sediments. Based on the equilibrium P concentrations, surface sediments behave as a source of P to the water column. A seven-day continuous drainage event exported 4.7 to 11.1 metric tons of suspended solids per farm, corresponding to 32 to 63 kg of particulate P being lost to downstream ecosystems. Drainage associated to a single seven-day storm event exported up to 61% of the total annual farm P load. It is evident from this study that short-term, high-intensity storm events can skew annual P loads due to the export of significantly higher particulate matter from farm canals. Exported particulates rich in P can provide a supplemental source of nutrients if captured and replenished back into the farmlands, as a sustainable farming practice.

  10. Storage filters upland suspended sediment signals delivered from watersheds

    Science.gov (United States)

    Pizzuto, James E.; Keeler, Jeremy; Skalak, Katherine; Karwan, Diana

    2017-01-01

    Climate change, tectonics, and humans create long- and short-term temporal variations in the supply of suspended sediment to rivers. These signals, generated in upland erosional areas, are filtered by alluvial storage before reaching the basin outlet. We quantified this filter using a random walk model driven by sediment budget data, a power-law distributed probability density function (PDF) to determine how long sediment remains stored, and a constant downstream drift velocity during transport of 157 km/yr. For 25 km of transport, few particles are stored, and the median travel time is 0.2 yr. For 1000 km of transport, nearly all particles are stored, and the median travel time is 2.5 m.y. Both travel-time distributions are power laws. The 1000 km travel-time distribution was then used to filter sinusoidal input signals with periods of 10 yr and 104 yr. The 10 yr signal is delayed by 12.5 times its input period, damped by a factor of 380, and is output as a power law. The 104 yr signal is delayed by 0.15 times its input period, damped by a factor of 3, and the output signal retains its sinusoidal input form (but with a power-law “tail”). Delivery time scales for these two signals are controlled by storage; in-channel transport time is insignificant, and low-frequency signals are transmitted with greater fidelity than high-frequency signals. These signal modifications are essential to consider when evaluating watershed restoration schemes designed to control sediment loading, and where source-area geomorphic processes are inferred from the geologic record.

  11. Modelling Suspended Sediment Transport in Monsoon Season: A Case Study of Pahang River Estuary, Pahang, Malaysia

    Science.gov (United States)

    Zakariya, Razak; Ahmad, Zuhairi; Saad, Shahbudin; Yaakop, Rosnan

    2013-04-01

    Sediment transport based on 2-dimensional real time model was applied to Pahang River estuary, Pahang, Malaysia and has been evaluated and verified with time series of tidal elevation, flow and suspended sediment load. Period of modelling was during highest high tide and lowest low tide in Northeast Monsoon (NE) which happened in December 2010 and Southwest Monsoon (SW) in July 2011. Simulated model outputs has been verify using Pearson's coefficient and has showed high accuracy. The validated model was used to simulate hydrodynamic and sediment transport of extreme conditions during both monsoon seasons. Based on field measurement and model simulation, tidal elevation and flow velocity, freshwater discharge of Pahang River were found to be higher during NE Monsoon. Based on the fluxes, the estuary also showed 'ebb-dominant' characteristic during highest high tide and lowest low tide in NE monsoon and normal ebbing-flooding characteristics during SW monsoon. In the Pahang River estuary, inflow and outflow patterns were perpendicular to the open boundary with circular flow formed at the shallow area in the middle of estuary during both monsoons. Referring to sea water intrusion from the river mouth, both seasons show penetration of more than 9 km (upstream input boundary) during higher high water tide. During higher lower water tide, the water intrusion stated varies which 5.6km during NE monsoon and 7.8km during SW monsoon. Regarding to the times lap during high tide, the sea water takes 2.8 hours to reach 9km upstream during NE monsoon compared to 1.9 hour during SW monsoon. The averages of suspended sediment concentration and suspended sediment load were higher during Northeast monsoon which increased the sedimentation potentials.Total of suspended sediment load discharged to the South China Sea yearly from Pahang River is approximately 96727.5 tonnes/day or 3.33 tonnes/km2/day which 442.6 tonnes/day during Northeast Monsoon and 25.3 tonnes/day during Southwest

  12. Elemental Spatiotemporal Variations of Total Suspended Particles in Jeddah City

    Directory of Open Access Journals (Sweden)

    Mohammad W. Kadi

    2014-01-01

    Full Text Available Elements associated with total suspended particulate matter (TSP in Jeddah city were determined. Using high-volume samplers, TSP samples were simultaneously collected over a one-year period from seven sampling sites. Samples were analyzed for Al, Ba, Ca, Cu, Mg, Fe, Mn, Zn, Ti, V, Cr, Co, Ni, As, and Sr. Results revealed great dependence of element contents on spatial and temporal variations. Two sites characterized by busy roads, workshops, heavy population, and heavy trucking have high levels of all measured elements. Concentrations of most elements at the two sites exhibit strong spatial gradients and concentrations of elements at these sites are higher than other locations. The highest concentrations of elements were observed during June–August because of dust storms, significant increase in energy consumption, and active surface winds. Enrichment factors of elements at the high-level sites have values in the range >10~60 while for Cu and Zn the enrichment factors are much higher (~0–>700 indicating that greater percentage of TSP composition for these three elements in air comes from anthropogenic activities.

  13. Influence of charge carriers on corrugation of suspended graphene

    Science.gov (United States)

    Kirilenko, Demid A.; Gorodetsky, Andrei; Baidakova, Marina V.

    2018-02-01

    Electronic degrees of freedom are predicted to play a significant role in mechanics of two-dimensional crystalline membranes. Here we show that appearance of charge carriers may cause a considerable impact on suspended graphene corrugation, thus leading to additional mechanism resulting in charge carriers mobility variation with their density. This finding may account for some details of suspended graphene conductivity dependence on its doping level and suggests that proper modeling of suspended graphene-based device properties must include the influence of charge carriers on its surface corrugation.

  14. Introduction to suspended-sediment sampling

    Science.gov (United States)

    Nolan, K. Michael; Gray, John R.; Glysson, G. Douglas

    2005-01-01

    Knowledge of the amount and timing of sediment transport in streams is important to those directly or indirectly responsible for developing and managing water and land resources. Such data are often used to judge the health of watershed and the success or failure of activities designed to mitigate adverse impacts of sediment on streams and stream habitats. This training class presents an introduction to methods currently used by the U.S. Geological Survey (USGS) to sample suspended-sediment concentrations in streams. The presentation is narrated, but you control the pace of the presentation. If the computer you are using can view 'MPEG' videos you will be able to take advantage of videos interspersed in the presentation. A test, found at the end of the presentation, can be taken to assess how well you understood the training material. The class, which is registered as class SW4416 with the National Training Center of the USGS, should take two or three hours to complete. In order to use the presentation provided via this Web page, you will need to download a large disc images (linked below) and 'burn' it to a blank CD-ROM using a CD-ROM recorder on your computer. The presentation will only run on a Windows-based personal computer (PC). The presentation was developed using Macromedia Director MX 20041 and is contained in the file 'SIR05-5077.exe' which should autolaunch. If it does not, the presentation can be started by double-clicking on the file name. A sound card and speakers are necessary to take advantage of narrations that accompany the presentation. Text of narrations is provided, if you are unable to listen to narrations. Instructions for installing and running the presentation are included in the file 'Tutorial.htm', which is on the CD. 1 Registered Trademark: Macromedia Incorporated

  15. [Rapid startup and nitrogen removal characteristic of anaerobic ammonium oxidation reactor in packed bed biofilm reactor with suspended carrier].

    Science.gov (United States)

    Chen, Sheng; Sun, De-zhi; Yu, Guang-lu

    2010-03-01

    Packed bed biofilm reactor with suspended carrier was used to cultivate ANAMMOX bacteria with sludge inoculums from WWTP secondary settler. The startup of ANAMMOX reactor was comparatively studied using high nitrogen loading method and low nitrogen loading method with aerobically biofilmed on the carrier, and the nitrogen removal characteristic was further investigated. The results showed that the reactor could be started up successfully within 90 days using low nitrogen loading method, the removal efficiencies of ammonium and nitrite were nearly 100% and the TN removal efficiencywas over 75% , however, the high nitrogen loading method was proved unsuccessfully for startup of ANAMMOX reactor probably because of the inhibition effect of high concentration of ammonium and nitrite. The pH value of effluent was slightly higher than the influent and the pH value can be used as an indicator for the process of ANAMMOX reaction. The packed bed ANAMMOX reactor with suspended carrier showed good characteristics of high nitrogen loading and high removal efficiency, 100% of removal efficiency could be achieved when the influent ammonium and nitrite concentration was lower than 800 mg/L.

  16. Atmospheric trace metal concentrations in Suspended Particulate ...

    African Journals Online (AJOL)

    The particulate samples from where the metals were characterized and quantified, were collected between December 2007 and March 2008, using a Gravimetric technique a portable SKC 506673 High volume Gravimetric sampler. The air particulate samples were collected from the kitchens, living rooms and outdoor ...

  17. Characterization of water quality and suspended sediment during cold-season flows, warm-season flows, and stormflows in the Fountain and Monument Creek watersheds, Colorado, 2007–2015

    Science.gov (United States)

    Miller, Lisa D.; Stogner, Sr., Robert W.

    2017-09-01

    From 2007 through 2015, the U.S. Geological Survey, in cooperation with Colorado Springs City Engineering, conducted a study in the Fountain and Monument Creek watersheds, Colorado, to characterize surface-water quality and suspended-sediment conditions for three different streamflow regimes with an emphasis on characterizing water quality during storm runoff. Data collected during this study were used to evaluate the effects of stormflows and wastewater-treatment effluent discharge on Fountain and Monument Creeks in the Colorado Springs, Colorado, area. Water-quality samples were collected at 2 sites on Upper Fountain Creek, 2 sites on Monument Creek, 3 sites on Lower Fountain Creek, and 13 tributary sites during 3 flow regimes: cold-season flow (November–April), warm-season flow (May–October), and stormflow from 2007 through 2015. During 2015, additional samples were collected and analyzed for Escherichia coli (E. coli) during dry weather conditions at 41 sites, located in E. coli impaired stream reaches, to help identify source areas and scope of the impairment.Concentrations of E. coli, total arsenic, and dissolved copper, selenium, and zinc in surface-water samples were compared to Colorado in-stream standards. Stormflow concentrations of E. coli frequently exceeded the recreational use standard of 126 colonies per 100 milliliters at main-stem and tributary sites by more than an order of magnitude. Even though median E. coli concentrations in warm-season flow samples were lower than median concentrations in storm-flow samples, the water quality standard for E. coli was still exceeded at most main-stem sites and many tributary sites during warm-season flows. Six samples (three warm-season flow and three stormflow samples) collected from Upper Fountain Creek, upstream from the confluence of Monument Creek, and two stormflow samples collected from Lower Fountain Creek, downstream from the confluence with Monument Creek, exceeded the acute water

  18. Ratios of total suspended solids to suspended sediment concentrations by particle size

    Science.gov (United States)

    Selbig, W.R.; Bannerman, R.T.

    2011-01-01

    Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

  19. Transport and Sources of Suspended Sediment in the Mill Creek Watershed, Johnson County, Northeast Kansas, 2006-07

    Science.gov (United States)

    Lee, Casey J.; Rasmussen, Patrick P.; Ziegler, Andrew C.; Fuller, Christopher C.

    2009-01-01

    The U.S. Geological Survey, in cooperation with the Johnson County Stormwater Management Program, evaluated suspended-sediment transport and sources in the urbanizing, 57.4 mi2 Mill Creek watershed from February 2006 through June 2007. Sediment transport and sources were assessed spatially by continuous monitoring of streamflow and turbidity as well as sampling of suspended sediment at nine sites in the watershed. Within Mill Creek subwatersheds (2.8-16.9 mi2), sediment loads at sites downstream from increased construction activity were substantially larger (per unit area) than those at sites downstream from mature urban areas or less-developed watersheds. Sediment transport downstream from construction sites primarily was limited by transport capacity (streamflow), whereas availability of sediment supplies primarily influenced transport downstream from mature urban areas. Downstream sampling sites typically had smaller sediment loads (per unit area) than headwater sites, likely because of sediment deposition in larger, less sloping stream channels. Among similarly sized storms, those with increased precipitation intensity transported more sediment at eight of the nine monitoring sites. Storms following periods of increased sediment loading transported less sediment at two of the nine monitoring sites. In addition to monitoring performed in the Mill Creek watershed, sediment loads were computed for the four other largest watersheds (48.6-65.7 mi2) in Johnson County (Blue River, Cedar, Indian, and Kill Creeks) during the study period. In contrast with results from smaller watersheds in Mill Creek, sediment load (per unit area) from the most urbanized watershed in Johnson County (Indian Creek) was more than double that of other large watersheds. Potential sources of this sediment include legacy sediment from earlier urban construction, accelerated stream-channel erosion, or erosion from specific construction sites, such as stream-channel disturbance during bridge

  20. Suspended sediment concentration profiles from synoptic satellite observations

    Digital Repository Service at National Institute of Oceanography (India)

    Ramakrishnan, R.; Rajawat, A; Chauhan, O.S.

    A method is developed to estimate vertical suspended sediment concentration (SSC) profiles in Gulf of Kachchh, from the sediment concentration values derived from synoptic observations of Ocean Colour Monitor (OCM). Under the influence of currents...

  1. Particles matter: Transformation of suspended particles in constructed wetlands

    NARCIS (Netherlands)

    Mulling, B.T.M.

    2013-01-01

    This thesis shows that constructed wetlands transform suspended particles in (treated) municipal wastewater through selective precipitation in ponds, biological filtering by plankton communities and physical and biological retention in reed beds. These processes effectively remove faecal indicator

  2. Suspended sediment apportionment in a South-Korean mountain catchment

    Science.gov (United States)

    Birkholz, Axel; Meusburger, Katrin; Park, Ji-Hyung; Alewell, Christine

    2016-04-01

    Due to the rapid agricultural expansion and intensification during the last decades in South-Korea, large areas of hill slope forests were transformed to paddies and vegetable fields. The intensive agriculture and the easily erodible soils in our catchment are a major reason for the increased erosion causing suspended sediments to infiltrate into the close drinking water reservoir. The drinking water reservoir Lake Soyang provides water supply for over ten million people in Seoul. Landscape managers need to know the exact origin of these sediments before they can create landscape amelioration schemes. We applied a compound-specific stable isotope (CSSI) approach (Alewell et al., 2015) to apportion the sources of the suspended sediments between forest and agricultural soil contribution to the suspended sediments in a different catchment and applied the same approach to identify and quantify the different sources of the suspended sediments in the river(s) contributing to Lake Soyang. We sampled eight soil sites within the catchment considering the different landuse types forest, rice paddies, maize and vegetables. Suspended sediments were sampled at three outlets of the different sub-catchments. Soils and suspended sediments are analysed for bulk carbon and nitrogen isotopes, compound-specific carbon isotopes of plant-wax derived long-chain fatty acids and long-chain n-alkanes. Fatty acid and alkane isotopes are then used in mixing calculations and the mixing model software IsoSource to find out the contribution of the different source soils to the suspended sediments. We present first data of the source soils and the suspended sediments. C. Alewell, A. Birkholz, K. Meusburger, Y. Schindler-Wildhaber, L. Mabit, 2015. Sediment source attribution from multiple land use systems with CSIA. Biogeosciences Discuss. 12: 14245-14269.

  3. Variability of suspended sediment yields within the Loire river basin (France)

    Science.gov (United States)

    Gay, A.; Cerdan, O.; Delmas, M.; Desmet, M.

    2014-11-01

    Suspended sediment fluxes and their variability in time and space have received much attention over the past decades. Large databases compiling suspended sediment load (SL) data are often used to serve these purposes. Analyses of these databases have highlighted the following two major limitations: (i) the role of lowland areas in sediment production and transfer has been minimised, and studies on small-scale catchments (with a drainage area of ⩽ 102 km2) are practically non-existent in the literature; and (ii) inhomogeneous data and calculation methods are used to estimate and compare the SL values. In this context, the present study aims to complete the existing studies by providing a reliable comparison of SL values for various catchments within lowland river basins. Therefore, we focused on the Loire and Brittany river basins (France). 111 small to large catchments covering 78% of this area and representative of the basins landscape diversity were chosen. We first present a large database of area-specific suspended sediment yields (SY) calculated from the suspended sediment concentration and flow discharge data over 7-40 yr of measurements at gauging stations. Two calculation methods are used, and the calculated loads are confined within a factor of 0.60-1.65 of the real values. Second, we analyse the temporal and spatial variability of the calculated SY values. Finally, using a nested catchment approach, we provide insight into sediment transport from upstream to downstream gauging stations and into the role of small- and medium- scale catchments in sediment production and transfers. The SL values at the outlet of the catchments range from 2.5 * 102 to 8.6 * 105 t yr-1, and the SY values range from 2.9 to 32.4 t km-2 yr-1. A comparison with the limited values available in the literature for this region corroborates our estimations. Sediment exports from the Loire and Brittany river basins are very low compared with mountainous regions and European exports

  4. Turbulence control of suspended matter aggregate size

    Science.gov (United States)

    Jago, C. F.; Jones, S. E.; Rippeth, T. P.; Simpson, J. H.

    2003-04-01

    The size and properties of the aggregates which comprise suspended particulate matter (SPM) change on short time and length scales in shelf seas. There is experimental and theoretical evidence to suggest that turbulence plays a key role in aggregation but there is contradictory evidence with respect to disaggregation: it has been proposed that sinking stresses, rather than turbulent stresses, are the dominant control of disaggregation. But there is little observational evidence for turbulence control of particle properties. New observations are presented which provide compelling evidence for turbulence control of both aggregation and disaggregation. TKE dissipation and particle size were measured in situ at stratified sites in the northern North Sea in 110 m water depth during the period of weakening of the seasonal thermocline (in October/November) and in the Clyde Sea in 55 m water depth (April). There were similar vertical distributions of TKE dissipation E, SPM concentration C, and particle size D at both sites. At the base of the thermocline, there were minima in E and C, but a maximum in D, indicating that enhanced aggregation was occurring in this region of low turbulent stress. In the bottom mixed layer, E and C increased, while D decreased due to disaggregation in this region of increasing turbulent stress towards the seabed. Particles settling out of the low stress region at the base of the thermocline began to disaggregate when E increased to 3.2x10-6 watts m-2. D did not correlate directly with E because aggregation is a function of collision frequency (and hence of both C and E): this can be accounted for using a simplified theoretical aggregation model which treats flocs as self-similar fractal entities and allows simultaneous floc formation and break up, specified as functions of C and E. It was found that in the northern North Sea the measured D represents an equilibrium size predicted by the model, while in the Clyde Sea tidal variation in both C

  5. Depth-integrated suspended sediment and geochemical fluxes in large rivers: the Amazon River system

    Science.gov (United States)

    Bouchez, J.; Lupker, M.; Gaillardet, J.; Metivier, F.; France-Lanord, C.; Maurice, L.

    2010-12-01

    with the strong correlation between grain size parameters and chemical composition of suspended sediment observed in our set of samples, we deduce the chemical composition of SPM throughout the cross-section, and thus the spatially-integrated chemical fluxes transported as suspended load for a number of elements. These results are finally compared with “simple” estimates relying on the geochemistry of channel surface suspended sediments. This highlights the different behaviors of chemical elements with respect to hydrodynamic sorting in large rivers. References: M.H. Garcia, 2008, Sedimentation engineering: processes, measurements, modeling and practice, EWRI. V. Galy et al., 2007, Nature 450 : 407-411. H. Rouse, 1950, Engineering Hydraulics, Wiley, New York. J. Bouchez et al., 2010, Hydrol. Proc., accepted.

  6. Evaluation of nonpoint-source contamination, Wisconsin: Land-use and Best-Management-Practices inventory, selected streamwater-quality data, urban-watershed quality assurance and quality control, constituent loads in rural streams, and snowmelt-runoff analysis, water year 1994

    Science.gov (United States)

    Walker, J.F.; Graczyk, D.J.; Corsi, S.R.; Owens, D.W.; Wierl, J.A.

    1995-01-01

    The objective of the watershed-management evaluation monitoring program in Wisconsin is to evaluate the effectiveness of best-management practices (BMP) for controlling nonpoint-source contamination in rural and urban watersheds. This report is an annual summary of the data collected for the program by the U.S Geological Survey and a report of the results of several different detailed analyses of the data. A land-use and BMP inventory is ongoing for 12 evaluation monitoring projects to track the sources of nonpoint-source pollution in each watershed and to document implementation of BMP's that may cause changes in the water quality of streams. Updated information is gathered each year, mapped, and stored in a geographic-information-system data base. Summaries of data collected during water years 1989-94 are presented. A water year is the period beginning October 1 and ending September 30; the water year is designated by the calendar year in which it ends. Suspended-sediment and total-phosphorus data (storm loads and annual loads) are summarized for eight rural sites. For all sites, the annual suspended-sediment or suspended-solids load for water year 1993 exceeded the average for the period of data collection; the minimum annual loads were transported in water year 1991 or 1992. Continuous dissolved-oxygen data were collected at seven rural sites during water year 1994. Data for water years 1990-93 are summarized and plotted in terms of percentage of time that a particular concentration is equaled or exceeded. Dissolved-oxygen concentrations in four streams were less than 9 mg/L at least 50 percent of the time, a condition that fails to meet suggested criterion for coldwater streams. The dissolved-oxygen probability curve for one of the coldwater streams is markedly different than the curves for the other streams, perhaps because of differences in aquatic biomass. Blank quality-assurance samples were collected at two of the urban evaluation monitoring sites to

  7. Photocurrent spectroscopy of exciton and free particle optical transitions in suspended carbon nanotube pn-junctions

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Shun-Wen [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089 (United States); Theiss, Jesse; Hazra, Jubin; Aykol, Mehmet; Kapadia, Rehan [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Cronin, Stephen B. [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089 (United States); Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Department of Chemistry, University of Southern California, Los Angeles, California 90089 (United States)

    2015-08-03

    We study photocurrent generation in individual, suspended carbon nanotube pn-junction diodes formed by electrostatic doping using two gate electrodes. Photocurrent spectra collected under various electrostatic doping concentrations reveal distinctive behaviors for free particle optical transitions and excitonic transitions. In particular, the photocurrent generated by excitonic transitions exhibits a strong gate doping dependence, while that of the free particle transitions is gate independent. Here, the built-in potential of the pn-junction is required to separate the strongly bound electron-hole pairs of the excitons, while free particle excitations do not require this field-assisted charge separation. We observe a sharp, well defined E{sub 11} free particle interband transition in contrast with previous photocurrent studies. Several steps are taken to ensure that the active charge separating region of these pn-junctions is suspended off the substrate in a suspended region that is substantially longer than the exciton diffusion length and, therefore, the photocurrent does not originate from a Schottky junction. We present a detailed model of the built-in fields in these pn-junctions, which, together with phonon-assistant exciton dissociation, predicts photocurrents on the same order of those observed experimentally.

  8. Acoustic backscatter by suspended cohesive sediments: Field observations, Seine Estuary, France

    Science.gov (United States)

    Sahin, Cihan; Verney, Romaric; Sheremet, Alexandru; Voulgaris, George

    2017-02-01

    Observations of suspended sediment size and concentration, flow and acoustic backscatter intensity collected on the Seine Estuary (France) are used to study the acoustic response in cohesive-sediment dominated environments. Estimates of suspended sediment concentration based on optical backscatter sensors and water samples are used to calibrate the acoustic backscatter intensity. The vertical structure of suspended sediment concentration is then estimated from acoustic backscatter information. To our knowledge, this is the first field application of the recently proposed model of acoustic scattering by flocculating suspensions based on the variation of particle density (floc-scattering model). The estimates of sediment concentration reproduce well the observations under different tidal (neap/spring) conditions, confirming the applicability of the new model in the field when detailed particle size measurements are available. When particle size measurements are not available, using estimated floc sizes based on the turbulence intensities may provide reasonable SSC profiles. During spring tide events (associated with strong currents, small flocs and large concentrations), the performances of the new floc-scattering model and the previous models given for solid particle-scattering are comparable. The floc-scattering model increases the quality of the SSC estimates especially during low-energy conditions characterized with larger flocs.

  9. Quantifying Flow and Pollutant Loading at Nested-Scales in a Mixed-Land-Use Watershed of the Central United States

    Science.gov (United States)

    Zeiger, S. J.; Hubbart, J. A.

    2016-12-01

    The impacts of land use on flow and pollutant loading regimes are poorly understood in mixed-land-use watersheds. Stream water quantity and quality was monitored using a nested-scale experimental watershed study design in a rapidly urbanizing mixed-land-use watershed of the central USA. Agricultural land use decreased by 18.4% and urban land use increased by 21.6% from the headwaters toward the watershed outlet. Four years of grab samples were collected at each site (n=836 samples per site) and analyzed for suspended sediment, total phosphorus, and inorganic nitrogen species during the study period (2010 - 2013). Daily flow and load duration curves were generated to quantify daily flow and pollutant yields at multiple flow intervals [high flow (0-10%), moist conditions (10-40%), mid-range flows (40-60%), dry conditions (60-90%), and low flow (90-100%)]. Greater than 92.1% of the total pollutant loads were transported during the high flow interval. Less than 0.1% suspended sediments and less than 1.0% TP-P were transported during mid-range conditions. Concentrations of NO3-N exceeding 5.0 mg L-1 were observed during moist conditions when median daily flow was 0.06 m3 s-1 in the headwaters where agricultural land use dominated 57% of the total drainage area (78.9 km2). The eutro-mesotrophic boundary was exceeded by a range of 37.8% (NO3-N in the agricultural headwaters) to 182.2% [(suspended sediment near the watershed outlet where urban land use accounted for 26% of the total drainage area (207.5 km2)] during the high flow interval. The eutro-mesotrophic boundary was exceeded by 56.3% for suspended sediment near the watershed outlet during moist conditions. However, the observed median daily pollutant loading did not exceed the load duration curve below the mid-range flow interval. Results highlight a critical need for pollutant monitoring at multiple flow intervals to capture the variability of pollutant loading in mixed-land-use watersheds.

  10. Controlling a negative loaded hydraulic cylinder using pressure feedback

    DEFF Research Database (Denmark)

    Hansen, M.R.; Andersen, T.O.

    2010-01-01

    This paper is concerned with the inherent oscillatory nature of pressure compensated velocity control of a hydraulic cylinder subjected to a negative load and suspended by means of an over-center valve. Initially, a linearized stability analysis of such a hydraulic circuit is carried out clearly...

  11. Organic matter dynamics and stable isotope signature as tracers of the sources of suspended sediment

    Science.gov (United States)

    Schindler Wildhaber, Y.; Liechti, R.; Alewell, C.

    2012-06-01

    Suspended sediment (SS) and organic matter in rivers can harm brown trout Salmo trutta by affecting the health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C), and nitrogen (N) during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13Ctot and 15N as input isotopes was used to quantify the temporal and spatial sources of SS. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ13Corg. Organic matter in SS increased from up- to downstream due to an increase of pasture and arable land downstream of the river. The mean fraction of SS originating from upper watershed riverbed sediment decreased from up to downstream and increased during high flow at all measuring sites along the course of the river. During base flow conditions, the major sources of SS are pasture, forest and arable land. The latter increased during rainy and warmer winter periods, most likely because both triggered snow melt and thus erosion. The measured increase in DOC and nitrate concentrations during high flow support these modeling results. Enhanced soil erosion processes on pasture and arable land are expected with increasing heavy rain events and less snow during winter seasons due to climate change. Consequently, SS and organic matter in the river will increase, which will possibly affect brown trout negatively.

  12. The phosphorus content of fluvial suspended sediment in three lowland groundwater-dominated catchments

    Science.gov (United States)

    Ballantine, Deborah J.; Walling, Desmond E.; Collins, Adrian L.; Leeks, Graham J. L.

    2008-07-01

    SummaryThis paper reports an investigation of the phosphorus (P) content of fluvial suspended sediment samples collected from three lowland groundwater-dominated agricultural catchments in the UK. In-stream trap samplers were installed at a total of 21 locations in the catchments of the Rivers Frome and Piddle in Dorset and in the Upper Tern in Shropshire, UK. Time-integrated suspended sediment samples ( n = 187) were collected at regular intervals over a period of 22 months and analysed for total phosphorus (TP), inorganic phosphorus (IP), organic phosphorus (OP) and algal available phosphorus (AAP). TP concentrations varied between sampling sites in the Rivers Frome and Piddle, allowing key P inputs to be identified, while fractionation of P assisted in identifying the nature of these inputs. There was also significant variation in both the TP concentration and the concentration of individual fractions between the Frome and Piddle catchments and the Upper Tern. These contrasts were attributed to the differing underlying geologies, since the Frome and Piddle are underlain predominantly by chalk, whilst the Upper Tern is underlain by sandstone, and also to the different soil types present. The TP content of suspended sediment collected from the Frome catchment showed a statistically significant relationship with specific surface area, but this relationship was not found for the remaining catchments. Temporal variation in P concentrations at both the seasonal and event scale was also investigated. Seasonal variations were noted for TP concentrations and for the concentrations of IP, OP and AAP in all the study catchments, but no consistent seasonal patterns were discernible. Maximum and minimum concentrations of the individual fractions occurred during different months in each of the study catchments, suggesting that different controls operated in the individual catchments. Short-term temporal variations in TP concentrations were documented for two high flow events

  13. Temperature signal in suspended sediment export from an Alpine catchment

    Science.gov (United States)

    Costa, Anna; Molnar, Peter; Stutenbecker, Laura; Bakker, Maarten; Silva, Tiago A.; Schlunegger, Fritz; Lane, Stuart N.; Loizeau, Jean-Luc; Girardclos, Stéphanie

    2018-01-01

    Suspended sediment export from large Alpine catchments ( > 1000 km2) over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation-deactivation of different sediment sources (proglacial areas, hillslopes, etc.), transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation). Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity), and the activation of different potential sources of fine sediment (sediment supply) in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment concentration through

  14. Sediment loads and transport at constructed chutes along the Missouri River - Upper Hamburg Chute near Nebraska City, Nebraska, and Kansas Chute near Peru, Nebraska

    Science.gov (United States)

    Densmore, Brenda K.; Rus, David L.; Moser, Matthew T.; Hall, Brent M.; Andersen, Michael J.

    2016-02-04

    estimate streamflow within each chute. The sampling design was developed to understand the suspended-sediment differences within each chute and between the chute and the Missouri River main channel during discrete sampling. The sampling design also allowed for site-specific surrogate relations between SSC and turbidity to be developed, which could be used to compute real-time estimates of SSC and sediment loads within the chutes. Real-time estimates of SSC and sediment loads enable a better understanding of sediment transport within the chutes during times when physical samples are not collected, including periods of high flow.

  15. Sediment Size Effects in Acoustic Doppler Velocimeter-Derived Estimates of Suspended Sediment Concentration

    Directory of Open Access Journals (Sweden)

    Mehmet Öztürk

    2017-07-01

    Full Text Available Backscatter output from a 10 MHz acoustic Doppler velocimeter (ADV was used to quantify suspended sediment concentrations in a laboratory setting using sand-sized particles. The experiments included (a well-sorted sand samples ranging in size from 0.112 to 0.420 mm, obtained by the sieving of construction sand, (b different, known mixtures of these well-sorted fractions, and (c sieved natural beach sand with median sizes ranging from 0.112 to 0.325 mm. The tested concentrations ranged from 25 to 3000 mg•L−1. The backscatter output was empirically related to concentration and sediment size, and when non-dimensionalized by acoustic wavelength, a dimensionless sediment size gradation coefficient. Size-dependent upper and lower bounds on measurable concentrations were also established empirically. The range of measurable conditions is broad enough to make the approach useful for sand sizes and concentrations commonly encountered in nature. A new method is proposed to determine concentrations in cases of mixed-size sediment suspensions when only calibration data for well-sorted constituent sands are available. This approach could potentially allow better estimates when the suspended load is derived from but is not fully representative of the bed material, and when the size characteristics of the suspended material are varying in time over the period of interest. Differences in results between the construction and beach sands suggest that sediment shape may also need to be considered, and point to the importance of calibrating to sediments encountered at the site of interest.

  16. 7Be/210Pbxs Ratio as an Indicator of Suspended Sediment Age or Fraction New Sediment in Suspension

    Science.gov (United States)

    Matisoff, G.; Wilson, C. G.; Whiting, P. J.

    2005-12-01

    We present a technique to use the 7Be/210Pbxs ratio as a measure of suspended sediment age or as an indicator of the fraction of the suspended sediment that is recently eroded from the landscape. Although both 7Be and 210Pbxs are delivered seasonally and stochastically to the landscape by precipitation, the ratio of the two radionuclides varies substantially less. The 7Be/210Pbxs ratios measured in three different watersheds decrease in the following manner: precipitation (~16) > suspended sediments in rivers (6-7) > suspended sediments in estuaries (4-6) > sediment collected in sediment traps in the estuary (~1) > surface sediment of the estuary (~0.5). Decreases in the 7Be/210Pbxs ratio in suspended sediments can be interpreted to be the result of increased age of the sediment, since 7Be decays faster than 210Pb. Alternatively, a decrease in the 7Be/210Pbxs ratio in suspended sediments can be interpreted to be the result of dilution of newly-tagged 7Be-rich sediment by 7Be-dead sediment, for example, by erosion of soil below the 7Be-enriched surface layer or by resuspension of 7Be-dead bottom sediment. We present a model which uses the 7Be/210Pbxs ratio in suspended sediments to determine the time since the particles were tagged by precipitation-derived radionuclides (i.e., the age of the suspended sediment). In addition, we present an alternative model to determine the fraction of the sediment that is `newly-tagged'. These two models are applied to three watersheds - Old Woman Creek, Ohio; Weeks Bay, Alabama; and South Slough, Oregon - and yield similar findings at all three sites. Sediment ages increase from 0 in newly tagged material to 50-80 days in rivers to about 80-100 days in the estuaries to about 200 days in the sediment traps to about 300 days on surface bottom sediments. Alternatively, the percent new sediment decreases from 100% in newly-tagged material to about 35-50% in rivers to 25-35% in the estuary to less than 10% in the sediment traps to 1

  17. Hydrodynamic and suspended sediment transport controls on river mouth morphology

    Science.gov (United States)

    Falcini, F.; Piliouras, A.; Garra, R.; Guerin, A.; Jerolmack, D. J.; Rowland, J.; Paola, C.

    2014-01-01

    mouths building into standing bodies of water have strikingly varied growth habits. This presents a compelling pattern formation problem that is also of great practical relevance for subsurface prediction and managing coastal wetlands. Here we present a generalized 2.5-dimensional potential vorticity (PV) theory that explains sedimentation patterns of a sediment-laden stationary jet by coupling an understanding of vorticity with suspended sediment concentration fields. We explore the physical meaning of this new sediment-PV definition, and its impact on outflow depositional patterns, by analyzing data from a shallow wall-bounded plane jet experiment and by discussing new theoretical insights. A key result is that lateral advection and diffusion of suspended sediment are directly proportional to jet vorticity, a feature that reveals the mechanistic process that forms elongated channels by focused levee deposition. The new PV theory constitutes a more generalized mathematical framework that expands the Rouse theory for the equilibrium of suspended sediment.

  18. Evaluation of intake efficiencies and associated sediment-concentration errors in US D-77 bag-type and US D-96-type depth-integrating suspended-sediment samplers

    Science.gov (United States)

    Sabol, Thomas A.; Topping, David J.

    2013-01-01

    with that predicted on the basis of the 1940s FISP laboratory experiments. Because suspended-sediment samplers can respond differently between laboratory and field conditions, actual-river tests such as those in this study should be conducted when models of suspended-sediment samplers are changed from one type to another during the course of long-term monitoring programs. Otherwise, potential large differences in the suspended-sediment data collected by different types of samplers would lead to large step changes in sediment loads that may be misinterpreted as real, when, in fact, they are associated with the change in suspended‑sediment sampling equipment.

  19. Quantifying the response of optical backscatter devices and transmissometers to variations in suspended particulate matter

    Science.gov (United States)

    Bunt, Jamie A. C.; Larcombe, Piers; Jago, Colin F.

    1999-07-01

    Optical instruments have been used effectively in studies of sediment dynamics for several decades. Without accurate instrument calibrations, calculated concentrations of suspended particulate matter (SPM) may be unreliable, with implications for interpretations of sedimentary processes and sediment fluxes. This review aims to quantify the effect of variations in SPM characteristics on the response of optical instruments (optical backscatter sensors OBS and transmissometers) and to note the implications for users of these instruments. A number of factors have a significant impact on instrument response, for example; a change in grain size from medium sands to fine silts may lead to a×100 increase in instrument response; flocculation of fine particles may decrease instrument response by×2; and the presence of plankton in suspension may lead to poor instrument calibrations of SPM concentration. Calibrations carried out in environments either with multi-modal bottom sediments, where flocculation of fine-grained sediments is likely, or where the hydrodynamics or grain type are highly variable must also include a determination of the changing nature of the suspended load in space and time. A more complete understanding of instrument response to SPM and of calibration requirements may enable optical devices to be used to a greater potential as long-term measures of SPM concentration, and also enable improvements in calculations of net sediment fluxes.

  20. Seasonal changes in suspended sediment load in the Gauthami-Godavari Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, N.P.C.; Rao, B.P.; Rao, K.M.; Rao, V.S.

    estuarine mouths. During pre-monsoon and northeast monsoon seasons, the CSM is mainly controlled by the tidal currents (10 cm/s to 150 cm/s) as the fresh water discharge during this period is minimum. Higher CSM (270 mg/l) at Vrudha estuarine mouth compared...

  1. Deep River Velocity and Sediment Profiles and the Suspended Sand Load,

    Science.gov (United States)

    1963-02-01

    5.03 x IO~~ ATCHAFALAVA RIVER WIDTH : 1587 FT D 5, : 6.75 w 0 ~ FT SIMM ESPORT u : 6.66 FPS WATER TEMP. : 70 F d : 46.3 FT FINE SAND PORTION OP BED...1.34 * 10 3FT SIMM ESPORT ~ : 5.85 FPS WATCR TEMP. :69 ’F d : 47.7 FT FiNE SAND PORTION OP BED MATERIAL : 39.$ ~~ FIG. 16...DEC. 14,196 1 Q : 218,000 CF’S S : 336 *io ’~ ATCHAFALAVA RIVERWIDTH ?~ FPS WATER TEMP : løOx I0~~ FT SIMM ESPORT d : 4 1 .7 FT FINE SAND PORTION OF B

  2. Total Sediment Load Measurement Using Point-Source Suspended-Sediment Data

    Science.gov (United States)

    1988-12-01

    Creek research catchment . Technical reviews of the report were provided by Drs. Steven R. Abt, E. V. Richardson, Daryl B. Simons, and Stanley A. Schumm...reaches: the Niobrara River at Cody, Nebraska (Colby and Hembree 1955); Fivemile Creek at Shoshoni, Wyoming (Colby, Hembree, and Rainwater 1956); the...figures encourage the selection of the Limerinos procedure. 4.3.2 Fivemile Creek Colby, Hembree, and Rainwater (1956) describe the study reaches and the

  3. Design of a LC-tuned magnetically suspended rotating gyroscope

    Science.gov (United States)

    Jin, Lichuan; Zhang, Huaiwu; Zhong, Zhiyong

    2011-04-01

    A inductor-capacitor (LC) tuned magnetically suspended rotating gyroscope prototype is designed and analyzed. High permeability ferrite cores are used for providing suspension force, and the rotation system is designed using the switched reluctance motor (SRM) principle. According to the LC-tuned principle, magnetic suspension force expression has been derived. The electromagnetic properties of the gyroscope are simulated by the Ansoft Maxwell software. And our result is expected to be able to serve as a prototype of micro-electromechanical system (MEMS) magnetically suspended rotating gyroscope in future practical applications.

  4. Quantum Hall effect in multi-terminal suspended graphene devices

    Science.gov (United States)

    Ghahari, Fereshte; Zhao, Yue; Bolotin, Kirill; Kim, Philip

    2010-03-01

    The integer and fractional quantum hall effects have been already observed in two terminal suspended graphene devices. However in this two probe device geometry, mixing between magnetoresistance ρxx and Hall resistance ρxy for incompletely developed quantum Hall states leads to substantial deviation of conductance plateaus values. In this talk, we present the experimental results from four terminal suspended graphene devices. The quality of quantum Hall effect will be discussed in muti-terminal device geometry in conjunction with the current-induced annealing process to improve the quality of graphene samples.

  5. Colorimetry Technique for Scalable Characterization of Suspended Graphene.

    Science.gov (United States)

    Cartamil-Bueno, Santiago J; Steeneken, Peter G; Centeno, Alba; Zurutuza, Amaia; van der Zant, Herre S J; Houri, Samer

    2016-11-09

    Previous statistical studies on the mechanical properties of chemical-vapor-deposited (CVD) suspended graphene membranes have been performed by means of measuring individual devices or with techniques that affect the material. Here, we present a colorimetry technique as a parallel, noninvasive, and affordable way of characterizing suspended graphene devices. We exploit Newton's rings interference patterns to study the deformation of a double-layer graphene drum 13.2 μm in diameter when a pressure step is applied. By studying the time evolution of the deformation, we find that filling the drum cavity with air is 2-5 times slower than when it is purged.

  6. Carbohydrate Loading.

    Science.gov (United States)

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  7. Monitoring stream sediment loads in response to agriculture in Prince Edward Island, Canada.

    Science.gov (United States)

    Alberto, Ashley; St-Hilaire, Andre; Courtenay, Simon C; van den Heuvel, Michael R

    2016-07-01

    Increased agricultural land use leads to accelerated erosion and deposition of fine sediment in surface water. Monitoring of suspended sediment yields has proven challenging due to the spatial and temporal variability of sediment loading. Reliable sediment yield calculations depend on accurate monitoring of these highly episodic sediment loading events. This study aims to quantify precipitation-induced loading of suspended sediments on Prince Edward Island, Canada. Turbidity is considered to be a reasonably accurate proxy for suspended sediment data. In this study, turbidity was used to monitor suspended sediment concentration (SSC) and was measured for 2 years (December 2012-2014) in three subwatersheds with varying degrees of agricultural land use ranging from 10 to 69 %. Comparison of three turbidity meter calibration methods, two using suspended streambed sediment and one using automated sampling during rainfall events, revealed that the use of SSC samples constructed from streambed sediment was not an accurate replacement for water column sampling during rainfall events for calibration. Different particle size distributions in the three rivers produced significant impacts on the calibration methods demonstrating the need for river-specific calibration. Rainfall-induced sediment loading was significantly greater in the most agriculturally impacted site only when the load per rainfall event was corrected for runoff volume (total flow minus baseflow), flow increase intensity (the slope between the start of a runoff event and the peak of the hydrograph), and season. Monitoring turbidity, in combination with sediment modeling, may offer the best option for management purposes.

  8. Sediment concentrations, loads, and particle-size distributions in the Red River of the North and selected tributaries near Fargo, North Dakota, during the 2011 spring high-flow event

    Science.gov (United States)

    Galloway, Joel M.; Blanchard, Robert A.; Ellison, Christopher A.

    2011-01-01

    To provide accurate and reliable information on sediment near the Fargo-Moorhead metropolitan area, the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers conducted a study in the spring (March-May) of 2010 and the spring of 2011 to examine sediment concentrations, loads, and particle-size distributions at nine selected sites in the Red River and its tributaries. Samples of suspended sediment, bed material, and bedload were collected at the nine sites at various time intervals during the high-flow events.

  9. Bone loss in tail-suspended rats in restricted to the unweighted limbs

    Science.gov (United States)

    Bikle, D. D.; Globus, R.; Morey-Holton, E. R.

    1984-01-01

    Space flight which results in certain characteristic changes in the skeleton and it was hypothesized that these abnormalities are a direct result of the weightless state. To determine the role of PTH and 1,25(OH)2D in the bone changes associated with weightlessness, we studied bone metabolism under various dietary conditions using an Earth based rat model system which simulates weightlessness. In this model, rats are suspended by their tails such that their rear limbs are completely unloaded while their fore limbs are normally loaded. It is suggested that skeletal unloading induces a localized defect in the unloaded bone which results in abnormal growth and mineralization. It is concluded that skeletal unloading may make the unloaded bone more or less sensitive to a systemic factor which in turn could account for a change in bone metabolism.

  10. Total contact cast wall load in patients with a plantar forefoot ulcer and diabetes.

    Science.gov (United States)

    Begg, Lindy; McLaughlin, Patrick; Vicaretti, Mauro; Fletcher, John; Burns, Joshua

    2016-01-01

    The total contact cast (TCC) is an effective intervention to reduce plantar pressure in patients with diabetes and a plantar forefoot ulcer. The walls of the TCC have been indirectly shown to bear approximately 30 % of the plantar load. A new direct method to measure inside the TCC walls with capacitance sensors has shown that the anterodistal and posterolateral-distal regions of the lower leg bear the highest load. The objective of this study was to directly measure these two regions in patients with Diabetes and a plantar forefoot ulcer to further understand the mechanism of pressure reduction in the TCC. A TCC was applied to 17 patients with Diabetes and a plantar forefoot ulcer. TCC wall load (contact area, peak pressure and max force) at the anterodistal and posterolateral-distal regions of the lower leg were evaluated with two capacitance sensor strips measuring 90 cm(2) (pliance®, novel GmbH, Germany). Plantar load (contact area, peak pressure and max force) was measured with a capacitance sensor insole (pedar®, novel GmbH, Germany) placed inside the TCC. Both pedar® and pliance® collected data simultaneously at a sampling rate of 50Hz synchronised to heel strike. The magnitude of TCC wall load as a proportion of plantar load was calculated. The TCC walls were then removed to determine the differences in plantar loading between the TCC and the cut down shoe-cast for the whole foot, rearfoot, midfoot and forefoot (region of interest). TCC wall load was substantial. The anterodistal lower leg recorded 48 % and the posterolateral-distal lower leg recorded 34 % of plantar contact area. The anterodistal lower leg recorded 28 % and the posterolateral-distal lower leg recorded 12 % of plantar peak pressure. The anterodistal lower leg recorded 12 % and the posterolateral-distal lower leg recorded 4 % of plantar max force. There were significant differences in plantar load between the TCC and the cut down shoe-cast for the whole foot, rearfoot, midfoot and

  11. Dynamics Modeling and Control of a Quadrotor with Swing Load

    Directory of Open Access Journals (Sweden)

    S. Sadr

    2014-01-01

    Full Text Available Nowadays, aerial robots or Unmanned Aerial Vehicles (UAV have many applications in civilian and military fields. For example, of these applications is aerial monitoring, picking loads and moving them by different grippers. In this research, a quadrotor with a cable-suspended load with eight degrees of freedom is considered. The purpose is to control the position and attitude of the quadrotor on a desired trajectory in order to move the considered load with constant length of cable. So, the purpose of this research is proposing and designing an antiswing control algorithm for the suspended load. To this end, control and stabilization of the quadrotor are necessary for designing the antiswing controller. Furthermore, this paper is divided into two parts. In the first part, dynamics model is developed using Newton-Euler formulation, and obtained equations are verified in comparison with Lagrange approach. Consequently, a nonlinear control strategy based on dynamic model is used in order to control the position and attitude of the quadrotor. The performance of this proposed controller is evaluated by nonlinear simulations and, finally, the results demonstrate the effectiveness of the control strategy for the quadrotor with suspended load in various maneuvers.

  12. Human health risk assessment based on trace metals in suspended air particulates, surface dust, and floor dust from e-waste recycling workshops in Hong Kong, China.

    Science.gov (United States)

    Lau, Winifred Ka Yan; Liang, Peng; Man, Yu Bon; Chung, Shan Shan; Wong, Ming Hung

    2014-03-01

    This study investigated health risks exerted on electronic waste (e-waste) recycling workers exposed to cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), mercury (Hg), and zinc (Zn) in Hong Kong. E-waste recycling workshops were classified into eight working areas: 1 = office, 2 = repair, 3 = dismantling, 4 = storage, 5 = desoldering, 6 = loading, 7 = cable shredding, and 8 = chemical waste. The aforementioned metal concentrations were analyzed in suspended air particulates, surface dust and floor dust collected from the above study areas in five workshops. Elevated Pb levels were measured in dismantling and desoldering areas (582 and 486 μg/100 cm(2) in surface and 3,610 and 19,172 mg/kg in floor dust, respectively). Blood lead levels of 10 and 39.5 μg/dl were estimated using United States Environmental Protection Agency's Adult Lead Model as a result of exposure to the floor dust from these two areas. Human health risk assessments were conducted to evaluate cancer and noncancer risks resulting from exposure to floor dust through the combined pathways of ingestion, dermal contact, and inhalation. Findings indicated that workers may be exposed to cancer risks above the acceptable range at 147 in a million at the 95th percentile in the dismantling area. Workers should be informed of associated risks to safeguard their health.

  13. Climate induced variability of suspended matter and nutrient in the discharge of Kali river, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Raghavan, B.R.; Chauhan, O.S.

    elevations above the riverbed following the methodology of Stern et al. (1986, 1991). Suspended particulate matter in the river water is estimated at 10 stations. The collection time in the estuarine samples was mid-tide synchronous during August..., in Manual and Guides 29, Paris, Scientific 9 committee on oceanic research, pp. 170. Stern, M. K., Jr. J. W. Day, and K. G. Teague (1986), Seasonality of materials transport through a coastal freshwater marsh: riverine versus tidal forcing...

  14. Spatial distribution of soil erosion and suspended sediment ...

    Indian Academy of Sciences (India)

    sediment transport rate for Chou-Shui river basin ... 5, Anzhong Road,. Tainan 70970, Taiwan. 4. Department of Hydraulics and Ocean Engineering, National Cheng-Kung University, No. 1,. University Road, Tainan ... surface runoff discharge, suspended sediment transport rate, quantity of soil erosion, and spatial distribu-.

  15. Calamine lotion: experimenting with a new suspending agent.

    Science.gov (United States)

    Al-Achi, A; Greenwood, R; Akin-Isijola, A; Bullard, J

    1999-01-01

    The use of a new suspending agent is investigated. Calamine lotion, USP contains bentonite magma as a suspending agent. In this study, bentonite magma was partially or completely replaced with a new suspending agent called tahini. Tahini is sesame paste composed of crushed sesame seeds in sesame oil. It is frequently used in middle eastern food as a thickening and suspending agent. Calamine lotion was prepared, generally, according to the USP method. The formula contained 40% v/v magma. Tahini was added instead of bentonite magma by replacing 100%, 99%, 90%, 75%, 50% and 25% of the magma. The sedimentation volume and the degree of flocculation were calculated for the resulting preparations. Rheological characteristics of bentonite- and tahini-containing lotions were also determined. Sedimentation volume showed 0.723 and 0.851 (p=0.05) for the lotions containing 100% bentonite and 100% tahini, respectively. The degree of flocculation was 2.00 and 2.35 (p=0.05) for the 100% bentonite and 100% tahini lotions, respectively. The rheograms of all the suspensions showed pseudoplastic flow. Overall, the use of tahini in calamine lotion has improved the physical stability of the formula.

  16. Turbulence Flow Characteristics of Suspended Sediments and its ...

    African Journals Online (AJOL)

    These are inturn integrated to give the hydraulic resistance law for sediment laden flow. The law of velocity distribution in open channel flow with suspended sediments was derived introducing Monin-Obukhov Length L . The distribution equation agrees well with the observation of velocity profile in the experiments.

  17. Microscopic characterisation of suspended graphene grown by chemical vapour deposition

    NARCIS (Netherlands)

    Bignardi, L.; Dorp, W.F. van; Gottardi, S.; Ivashenko, O.; Dudin, P.; Barinov, A.; de Hosson, J.T.M.; Stöhr, M.; Rudolf, P.

    2013-01-01

    We present a multi-technique characterisation of graphene grown by chemical vapour deposition (CVD) and thereafter transferred to and suspended on a grid for transmission electron microscopy (TEM). The properties of the electronic band structure are investigated by angle-resolved photoelectron

  18. Comparison of Suspended Solid Separation in Advanced Storm Overflow Structures

    DEFF Research Database (Denmark)

    Larsen, Torben; Sørensen, Morten Steen

    1990-01-01

    This paper describes a laboratory investigation of the separation of suspended solids in a circular weir overflow and a vortex separator. The basic idea is to evaluate the efficiency of a vortical flow in the overflow chamber, and to compare these results with other overflow structures....

  19. Current-use insecticides, phosphates and suspended solids in the ...

    African Journals Online (AJOL)

    In Western Cape orchard areas, the last pesticide application of the growing season in summer takes place at the end of February. Pesticides, total phosphates and total suspended solids (TSS) were measured in the Lourens River at the beginning of April 1999 prior to the first rainfall of the rainy season and in the middle of ...

  20. Reduction in density of suspended - sediment - laden natural waters

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Desa, E.; Desa, E.; Smith, D.; Peshwe, V.B.; VijayKumar, K.; Desa, J.A.E.

    to 0.4% - 4.5%) that of the density of the same water without suspended sediment. Teh values of peff in a given site differed from one tidal cycle to another (approx equal to 1.9%). These values varied slightly (less than 0.8%) from mid-tide to slack...

  1. Transport of suspended particles in turbulent open channel flows

    NARCIS (Netherlands)

    Breugem, W.A.

    2012-01-01

    Two experiments are performed in order to investigate suspended sediment transport in a turbulent open channel flow. The first experiment used particle image velocimetry (PIV) to measure the fluid velocity with a high spatial resolution, while particle tracking velocimetry (PTV) was used to measure

  2. Spatial Distribution of Suspended Particulate Matter in Mtwapa ...

    African Journals Online (AJOL)

    Surface water concentrations of inorganic nutrients and suspended particulate matter (SPM) components from Mtwapa and Shirazi creeks in Kenya were measured and compared. This was aimed at assessing the contribution of phytoplankton carbon, particulate organic carbon (POC) and detritus on the total SPM pool, and ...

  3. Nature of suspended particulate matter and concentrations of heavy ...

    African Journals Online (AJOL)

    The concentrations of metals in bottom sediment in the Tanzanian waters of Lake Victoria and the nature of suspended particulate matter (SPM) were analysed. The objective of the study was to compare levels of metals in sediment from different locations and to establish their sources. Metal concentrations were higher in ...

  4. Stabilised suspending efficiency of Laponite XLG and sodium ...

    African Journals Online (AJOL)

    Charged drugs like Sulphamerazine may make pseudoplastic/plastic materials become Newtonian and loose their suspending power. In this study ... For this purpose, the rheograms of the systems were obtained by the use of a Haake rotoviscometer RV 12 utilizing a cup and rotor sensor system MV 1. In the absence of ...

  5. Spin Transport in High-Quality Suspended Graphene Devices

    NARCIS (Netherlands)

    Guimaraes, Marcos H. D.; Veligura, A.; Zomer, P. J.; Maassen, T.; Vera-Marun, I. J.; Tombros, N.; van Arees, B. J.; Wees, B.J. van

    We measure spin transport in high mobility suspended graphene (mu approximate to 10(5)cm(2)/(V s)), obtaining a (spin) diffusion coefficient of 0.1 m(2)/s and giving a lower bound on the spin relaxation time (tau(s) approximate to 150 ps) and spin relaxation length (lambda(s) = 4.7 mu m) for

  6. 40 CFR 52.330 - Control strategy: Total suspended particulates.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Total suspended... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.330 Control strategy..., the State must repromulgate Regulation No. 1 to satisfy reasonably available control technology...

  7. Evaluation of the suspending properties of Abizia zygia gum on ...

    African Journals Online (AJOL)

    Method: The suspending properties of Albizia zygia gum (family Mimosoideae) were evaluated comparatively with those of Compound Tragacanth, Acacia and Gelatin at concentration range of 0.5 – 4.0%w/v in Sulphadimidine suspension. Characterization tests were carried out on purified Albizia zygia gum. Sedimentation ...

  8. Discrete Dynamics of Nanoparticle Channelling in Suspended Graphene

    DEFF Research Database (Denmark)

    Booth, Tim; Pizzocchero, Filippo; Andersen, Henrik

    2011-01-01

    We have observed a previously undescribed stepwise oxidation of mono- and few layer suspended graphene by silver nanoparticles in situ at subnanometer scale in an environmental transmission electron microscope. Over the range of 600–850 K, we observe crystallographically oriented channelling...

  9. Method for separating biological cells. [suspended in aqueous polymer systems

    Science.gov (United States)

    Brooks, D. E. (Inventor)

    1980-01-01

    A method for separating biological cells by suspending a mixed cell population in a two-phase polymer system is described. The polymer system consists of droplet phases with different surface potentials for which the cell populations exhibit different affinities. The system is subjected to an electrostatic field of sufficient intensity to cause migration of the droplets with an attendant separation of cells.

  10. Opportunities Suspended: The Disparate Impact of Disciplinary Exclusion from School

    Science.gov (United States)

    Losen, Daniel J.; Gillespie, Jonathan

    2012-01-01

    Well over three million children, K-12, are estimated to have lost instructional "seat time" in 2009-2010 because they were suspended from school, often with no guarantee of adult supervision outside the school. That's about the number of children it would take to fill every seat in every major league baseball park and every NFL stadium…

  11. Investigation of suspended sediment transport using ultrasonic techniques

    DEFF Research Database (Denmark)

    Bjørnø, Irina; Jensen, Leif Bjørnø

    1994-01-01

    The results of the initial experimental studies involving the scattering of ultrasonic signals from canonical and non-canonical shaped suspended particles with known elastical qualities are reported. These results have formed the basis for the development of a numerical model for ultrasound...

  12. Microwave-induced nonequilibrium temperature in a suspended carbon nanotube

    NARCIS (Netherlands)

    Hortensius, H.L.; Öztürk, A.; Zeng, P.; Driessen, E.F.C.; Klapwijk, T.M.

    2012-01-01

    Antenna-coupled suspended single carbon nanotubes exposed to 108?GHz microwave radiation are shown to be selectively heated with respect to their metal contacts. This leads to an increase in the conductance as well as to the development of a power-dependent DC voltage. The increased conductance

  13. Scanning tunneling spectroscopy of suspended single-wall carbon nanotubes

    NARCIS (Netherlands)

    LeRoy, B.J.; Lemay, S.G.; Kong, J.; Dekker, C.

    2004-01-01

    We have performed low-temperature scanning tunneling microscopy measurements on single-wall carbon nanotubes that are freely suspended over a trench. The nanotubes were grown by chemical vapor deposition on a Pt substrate with predefined trenches etched into it. Atomic resolution was obtained on the

  14. Evaluation of the Suspending Properties of the Coprecipitate of ...

    African Journals Online (AJOL)

    The suspending ability of the different ratios was evaluated in magnesium trisilicate suspension, and compared with a suspension prepared with Compound Tragacanth Powder BP (CTP) as well as a commercially available magnesium trisilicate suspension (MTS). The parameters tested were sedimentation rate, flow rate, ...

  15. Suspended microstructures of epoxy based photoresists fabricated with UV photolithography

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Anhøj, Thomas Aarøe; Caviglia, Claudia

    2017-01-01

    In this work we present an easy, fast, reliable and low cost microfabrication technique for fabricating suspended microstructures of epoxy based photoresistswith UV photolithography. Two different fabrication processes with epoxy based resins (SU-8 and mr-DWL) using UV exposures at wavelengths...

  16. Prediction and forecast of Suspended Sediment Concentration (SSC) on the Upper Yangtze basin

    Science.gov (United States)

    Matos, José Pedro; Hassan, Marwan; Lu, Xixi; Franca, Mário J.

    2017-04-01

    Sediment transport in suspension may represent 90% or more of the global annual flux of sediment. For instance, more than 99% of the sediment supplied to the sea by the Yangtze River is suspended load. Suspended load is an important component for understanding channel dynamics and landscape evolution. Sediments transported in suspension are a major source of nutrients for aquatic organisms in riparian and floodplain habitats, and play a beneficial role acting as a sink in the carbon cycle. Excess of fine sediments may also have adverse effects. It can impair fish spawning by riverbed clogging, disturb foraging efficiency of hunting of river fauna, cause algae and benthos scouring, reduce or inhibit exchanges through the hyporheic region. Accumulation of fine sediments in reservoirs reduces storage capacity. Although fine sediment dynamics has been the focus of many studies, the current knowledge of sediment sources, transfer, and storage is inadequate to address fine sediment dynamics in the landscape. The theoretical derivation of a complete model for suspended sediment transport at the basin scale, incorporating small scale processes of production and transport, is hindered because the underlying mechanisms are produced at different non-similar scales. Availability of long-term reliable data on suspended sediment dynamics is essential to improve our knowledge on transport processes and to develop reliable sediment prediction models. Over the last 60 years, the Yangtze River Commission has been measuring the daily Suspended Sediment Concentration (SSC) at the Pingshan station. This dataset provides a unique opportunity to examine temporal variability and controls of fine sediment dynamics in the Upper Yangtze basin. The objective of this study is to describe temporal variation of fine sediment dynamics at the Pingshan station making use of the extensive sediment monitoring program undertaken at that location. We test several strategies of prediction and forecast

  17. A suspended-particle rosette multi-sampler for discrete biogeochemical sampling in low-particle-density waters

    Energy Technology Data Exchange (ETDEWEB)

    Breier, J. A.; Rauch, C. G.; McCartney, K.; Toner, B. M.; Fakra, S. C.; White, S. N.; German, C. R.

    2010-06-22

    To enable detailed investigations of early stage hydrothermal plume formation and abiotic and biotic plume processes we developed a new oceanographic tool. The Suspended Particulate Rosette sampling system has been designed to collect geochemical and microbial samples from the rising portion of deep-sea hydrothermal plumes. It can be deployed on a remotely operated vehicle for sampling rising plumes, on a wire-deployed water rosette for spatially discrete sampling of non-buoyant hydrothermal plumes, or on a fixed mooring in a hydrothermal vent field for time series sampling. It has performed successfully during both its first mooring deployment at the East Pacific Rise and its first remotely-operated vehicle deployments along the Mid-Atlantic Ridge. It is currently capable of rapidly filtering 24 discrete large-water-volume samples (30-100 L per sample) for suspended particles during a single deployment (e.g. >90 L per sample at 4-7 L per minute through 1 {mu}m pore diameter polycarbonate filters). The Suspended Particulate Rosette sampler has been designed with a long-term goal of seafloor observatory deployments, where it can be used to collect samples in response to tectonic or other events. It is compatible with in situ optical sensors, such as laser Raman or visible reflectance spectroscopy systems, enabling in situ particle analysis immediately after sample collection and before the particles alter or degrade.

  18. Treatment of low strength sewage with high suspended organic matter content in an anaerobic sequencing batch reactor and modeling application

    OpenAIRE

    Donoso-Bravo,Andrés; Carballa, Marta; Ruiz- Filippi,Gonzalo; Chamy, Rolando

    2009-01-01

    In this work, an anaerobic sequencing batch reactor (ASBR) was operated for 8 months to treat low strength sewage with high suspended organic matter content. Three phases of operation with increasing organic loading rates (OLR) were performed: 0.4 kg COD/m³ x d (phase I), 0 .8 kg COD/m³ x d (phase II) and 1.2 kg COD/m³ x d (phase III). Adequate stability parameters (pH, total alkalinity) were obtained through all three experimental phases. During phases I and II, the removal efficiencies of o...

  19. Assessment of catchment scale connectivity in different catchments using measured suspended sediment output

    Science.gov (United States)

    Masselink, Rens; Keesstra, Saskia; Seeger, Manuel

    2014-05-01

    Recent developments in hydrology and geomorphology include the connectivity principle, which describes how different elements in a landscape are connected and how water and matter moves between these elements. So far, studies on connectivity have been mainly of a conceptual nature and have been done on a small scale, while studies that map, quantitatively establish relations, and model water and sediment transport in connectivity are rare. In this study we established a relation between change in connectivity within four catchments and the time of year by using suspended sediment data. The data were collected for four catchments in Navarra, Spain of which two catchments are dominated by forest and pasture, while the other two catchments are dominated by agriculture and have no forest. Data were collected during a 13 year period; 4 samples were taken a day at 6 hour intervals which were mixed to obtain a daily average suspended sediment concentration. This was then converted into daily suspended sediment output using the measured total daily discharge. The effect of precipitation on the sediment output data was minimized by using an antecedent precipitation index (API), which consists of the precipitation of the current day added by the precipitation of the previous 14 days, where the influence of the previous days decays exponentially with time. The daily total suspended sediment output was divided by the API, to obtain a measure for sediment output independent of precipitation. This sediment output then serves as a measure for the connectivity within the catchment. The connectivity of the four catchments throughout the years will be compared to each other and we hypothesise that the two catchments dominated by forests and pastures will change only slightly throughout the year, whereas we expect to see large differences in connectivity in the two agricultural catchments. The agricultural catchments are likely to display a highly varying connectivity throughout the

  20. Treatment of wastewater containing a large amount of suspended solids by a novel multi-staged UASB reactor.

    Science.gov (United States)

    Uemura, S; Harada, H; Ohashi, A; Torimura, S

    2005-12-01

    Treatment of artificial wastewater containing a large amount of suspended solids comprised of soybean processing waste and pig fodder was studied using a novel multi-staged upflow anaerobic sludge blanket reactor. The reactor consisted of three compartments, each containing a gas solid separator. The wastewater had chemical oxygen demand of approximately 21600 mg l(-1), suspended solids of 12800 mg l(-1), and an ammonia concentration of 945 mg l(-1). A continuous experiment without effluent circulation showed that the multi-staged reactor was not that effective for the treatment of wastewater containing a large amount of suspended solids. However, operation of the reactor with circulation of effluent enabled the reactor to achieve organic removal of 85% and approximately 70% methane conversion at loading rates of between 4.0 to 5.4 kg-chemical oxygen demand per cubic meter per day, meaning that the reactor was more effective when effluent was circulated. Morphological investigation revealed that the crude fiber in the sludge was partially degraded and that it had many small depressions on its surface. Evolved biogas may have become caught in these depressions of the fibers and caused washout of the sludge.

  1. Temperature signal in suspended sediment export from an Alpine catchment

    Directory of Open Access Journals (Sweden)

    A. Costa

    2018-01-01

    Full Text Available Suspended sediment export from large Alpine catchments ( >  1000 km2 over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation–deactivation of different sediment sources (proglacial areas, hillslopes, etc., transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation. Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity, and the activation of different potential sources of fine sediment (sediment supply in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment

  2. Effects of Suspended Sediment on Early Life Stages of Smallmouth Bass (Micropterus dolomieu).

    Science.gov (United States)

    Suedel, Burton C; Wilkens, Justin L; Kennedy, Alan J

    2017-01-01

    The resuspension of sediments caused by activities, such as dredging operations, is a concern in Great Lakes harbors where multiple fish species spawn. To address such concerns, smallmouth bass (Micropterus dolomieu) were exposed to uncontaminated suspended sediment (nominally 0, 100, 250, and 500 mg/L) continuously for 72 h to determine the effects on egg-hatching success and swim-up fry survival and growth. The test sediments were collected from two harbors: (1) fine-grained sediment in Grand Haven Harbor, Lake Michigan, and (2) coarser-grained sediment in Fairport Harbor, Lake Erie. Eggs exposed to total suspended solids (TSS) concentrations >100 mg/L resulted in decreased survival of post-hatch larval fish. Fry survival was >90 % at the highest exposure concentration (500 mg/L), but growth was decreased when the exposure concentration was >100 mg/L. Growth and survival of swim-up fry held for a 7- and 26-day post-exposure the grow-out period was variable suggesting that the sediment grain size and strain of fish may influence lingering effects after the cessation of exposure. The results suggest that exposed eggs hatched normally; however, newly hatched larvae, which are temporarily immobile, are more vulnerable to the effects of suspended sediment. The swim-up fry were found to be more sensitive to high TSS concentrations in sandy relative to silty sediment. These data represent a conservative exposure scenario that can be extrapolated to high-energy systems in the field to inform management decisions regarding the necessity for dredging windows or need to implement controls to protect M. dolomieu.

  3. Spatial variability of suspended sediment concentration within a tidal marsh in San Francisco Estuary

    Science.gov (United States)

    Swanson, K.; Drexler, J. Z.; Schoellhamer, D. H.; Buffington, K.; Takekawa, J.

    2012-12-01

    The sustainability of existing marshes and feasibility of future marsh restoration projects in San Francisco Estuary and elsewhere are threatened by a potential imbalance between accelerating sea-level rise and tidal marsh accretion rates. Marsh accretion is, in large part, dependent upon the availability of suspended sediment supplied from adjacent waterways. As water and sediment move across a marsh plain, suspended sediment settles and is trapped by vegetation near the source, resulting in less suspended-sediment concentration (SSC) and deposition in the interior of the marsh. Measurements of deposition and limited observations of SSC within marshes have confirmed a decrease in sediment supply and accumulation from the marsh edge to the marsh interiors, but the spatial variability of SSC has not been quantified in a manner that allows for comparison to a theoretical sediment transport model. For this study, transects of SSC were collected within a marsh at China Camp State Park in the San Francisco Estuary which demonstrate that a dominant pattern of settling can be quantified and generally matches the exponentially decreasing pattern of SSC predicted by a simple advection-settling model. The observed pattern suggests that sediment settling and marsh flow characteristics are consistent both spatially (between transects) and temporally (between monthly sampling events). However, deviations from the predicted pattern occurred systematically at some locations and are likely related to resuspension of sediment from the marsh surface or small, unmapped creek channels that supply sediment to the marsh. Despite these deviations, our data show this simple 1-D model of advection and settling can be used to generalize within-marsh sediment transport as a function of distance from the nearest sediment source.

  4. Suspended sediment profiles derived from spectral attenuation coefficients measurements using neural network method

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, G.; Suresh, T.; Matondkar, S.G.P.; Desa, E.; Kamath, S.S.

    total suspended matter values from water samples obtained at discrete depths at the same location. An artificial neural network (ANN) model has been used to derive suspended matter from the spectral values of beam attenuation coefficients measured using...

  5. Impact of sound attenuation by suspended sediment on ADCP backscatter calibrations

    NARCIS (Netherlands)

    Sassi, M.G.; Hoitink, A.J.F.; Vermeulen, B.

    2012-01-01

    Although designed for velocity measurements, acoustic Doppler current profilers (ADCPs) are widely being used to monitor suspended particulate matter in rivers and in marine environments. To quantify mass concentrations of suspended matter, ADCP backscatter is generally calibrated with in situ

  6. Effect of Martian Suspended Dust on Albedo Measurements from the MGS-TES Data

    OpenAIRE

    A. Zinzi; Palomba, E.; Rinaldi, G.; d'Amore, M.

    2010-01-01

    Suspended dust on Mars influences albedo measurements by orbiting instruments, but not necessary the real surface albedo. The aim of this study is to characterize the role of suspended aerosols on albedo measurement by remote sensing instruments.

  7. Design, analysis and control of cable-suspended parallel robots and its applications

    CERN Document Server

    Zi, Bin

    2017-01-01

    This book provides an essential overview of the authors’ work in the field of cable-suspended parallel robots, focusing on innovative design, mechanics, control, development and applications. It presents and analyzes several typical mechanical architectures of cable-suspended parallel robots in practical applications, including the feed cable-suspended structure for super antennae, hybrid-driven-based cable-suspended parallel robots, and cooperative cable parallel manipulators for multiple mobile cranes. It also addresses the fundamental mechanics of cable-suspended parallel robots on the basis of their typical applications, including the kinematics, dynamics and trajectory tracking control of the feed cable-suspended structure for super antennae. In addition it proposes a novel hybrid-driven-based cable-suspended parallel robot that uses integrated mechanism design methods to improve the performance of traditional cable-suspended parallel robots. A comparative study on error and performance indices of hybr...

  8. Use of an oxidative destruction and quadrupole mass spectrometric (QMS) detection for the determination of the organic elemental composition of suspended matter in surface water

    NARCIS (Netherlands)

    Reijnders, H.F.R.; Onderdelinden, D.; Visser, M.G.; Griepink, B.

    1980-01-01

    A study was made of the applicability of a system consisting of a combustion followed by QMS-detection for the determination of the elemental composition of organic matter suspended in surface water. The solid material obtained from several types of water was collected by centrifugation. The results

  9. Prevalence and pathogen load of Campylobacter spp., Salmonella enterica and Escherichia coli O157/O145 serogroup in sheep faeces collected at sale yards and in abattoir effluent in Western Australia.

    Science.gov (United States)

    Yang, R; Abraham, S; Gardner, G E; Ryan, U; Jacobson, C

    2017-05-01

    Develop a multiplex quantitative PCR assay to investigate the prevalence and shedding of Escherichia coli O157/O145, Salmonella spp. and Campylobacter spp. in sheep at sale yards and abattoirs. A qPCR for E. coli O157/O145 was developed, validated and multiplexed with an existing qPCR for Campylobacter and Salmonella enterica. The absolute numbers of E. coli O157/O145, Campylobacter and Salmonella in control samples was determined using droplet digital PCR. These were then used as the controls in the multiplex qPCR on a total of 474 sheep faecal samples collected from two saleyards over a 4-month period (April-July 2014) and 96 effluent samples from an abattoir. The mutiplex qPCR was specific with a sensitivity of 5 organisms/μL faecal DNA extract for Campylobacter, S. enterica and E. coli O157/O145. The overall prevalence of Campylobacter, S. enterica and E. coli O157/O145 in faecal samples was 5.7%, 3.6% and 8.4% and in effluent samples was 18.8%, 6.3% and 5.2%, respectively. The pathogen loads of Campylobacter, S. enterica and E. coli O157/O145 in faecal and effluent samples was also determined via mutiplex qPCR. The overall prevalences of Campylobacter, S. enterica and E. coli O157/O145 were generally low (<6%), but point prevalences ranged considerably in healthy sheep (up to 26% for E. coli O157/O145). Further work to determine risk factors for shedding of bacterial organisms in meat sheep in the pre-slaughter period (on-farm, sale yards and lairage at abattoirs) could further reduce the risk of contamination of meat products. © 2017 Australian Veterinary Association.

  10. 48 CFR 52.209-6 - Protecting the Government's Interest When Subcontracting With Contractors Debarred, Suspended, or...

    Science.gov (United States)

    2010-10-01

    ...'s Interest When Subcontracting With Contractors Debarred, Suspended, or Proposed for Debarment. 52....209-6 Protecting the Government's Interest When Subcontracting With Contractors Debarred, Suspended... Government's Interest When Subcontracting With Contractors Debarred, Suspended, or Proposed for Debarment...

  11. Occurrence and persistence of fungicides in bed sediments and suspended solids from three targeted use areas in the United States

    Science.gov (United States)

    Smalling, Kelly L.; Reilly, Timothy J.; Sandstrom, Mark W.; Kuivila, Kathryn

    2013-01-01

    To document the environmental occurrence and persistence of fungicides, a robust and sensitive analytical method was used to measure 34 fungicides and an additional 57 current-use pesticides in bed sediments and suspended solids collected from areas of intense fungicide use within three geographic areas across the United States. Sampling sites were selected near or within agricultural research farms using prophylactic fungicides at rates and types typical of their geographic location. At least two fungicides were detected in 55% of the bed and 83% of the suspended solid samples and were detected in conjunction with herbicides and insecticides. Six fungicides were detected in all samples including pyraclostrobin (75%), boscalid (53%), chlorothalonil (41%) and zoxamide (22%). Pyraclostrobin, a strobilurin fungicide, used frequently in the United States on a variety of crops, was detected more frequently than p,p′-DDE, the primary degradate of p,p′-DDT, which is typically one of the most frequently occurring pesticides in sediments collected within highly agricultural areas. Maximum fungicide concentrations in bed sediments and suspended solids were 198 and 56.7 μg/kg dry weight, respectively. There is limited information on the occurrence, fate, and persistence of many fungicides in sediment and the environmental impacts are largely unknown. The results of this study indicate the importance of documenting the persistence of fungicides in the environment and the need for a better understanding of off-site transport mechanisms, particularly in areas where crops are grown that require frequent treatments to prevent fungal diseases.

  12. 78 FR 48145 - Lemon Juice From Argentina: Continuation of Suspended Antidumping Duty Investigation

    Science.gov (United States)

    2013-08-07

    ... Doc No: 2013-19067] DEPARTMENT OF COMMERCE International Trade Administration [A-357-818] Lemon Juice... of the suspended investigation on lemon juice from Argentina would likely lead to continuation or... of the suspended antidumping duty investigation on lemon juice from Argentina (``suspended...

  13. Suspended 3D pyrolytic carbon microelectrodes for electrochemistry

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Caviglia, Claudia; Keller, Stephan Sylvest

    2017-01-01

    Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. This work presents the fabrication and characterization of suspended pyrolytic carbon microstructures serving as three-dimensional (3D) carbon microelectrodes for electrochem...... resistance as compared to 2D carbon electrodes. The higher sensitivity of 3D carbon microelectrodes for electrochemical sensing was illustrated by dopamine detection.......Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. This work presents the fabrication and characterization of suspended pyrolytic carbon microstructures serving as three-dimensional (3D) carbon microelectrodes...... for electrochemical applications. A 3D polymer template in epoxy based photoresist (SU-8) was fabricated with multiple steps of UV photolithography and pyrolysed at 900 °C to obtain 3D carbon microelectrodes. The pyrolytic carbon microstructures were characterized by SEM, Raman spectroscopy and XPS to determine...

  14. Approximate Series Solutions for Nonlinear Free Vibration of Suspended Cables

    Directory of Open Access Journals (Sweden)

    Yaobing Zhao

    2014-01-01

    Full Text Available This paper presents approximate series solutions for nonlinear free vibration of suspended cables via the Lindstedt-Poincare method and homotopy analysis method, respectively. Firstly, taking into account the geometric nonlinearity of the suspended cable as well as the quasi-static assumption, a mathematical model is presented. Secondly, two analytical methods are introduced to obtain the approximate series solutions in the case of nonlinear free vibration. Moreover, small and large sag-to-span ratios and initial conditions are chosen to study the nonlinear dynamic responses by these two analytical methods. The numerical results indicate that frequency amplitude relationships obtained with different analytical approaches exhibit some quantitative and qualitative differences in the cases of motions, mode shapes, and particular sag-to-span ratios. Finally, a detailed comparison of the differences in the displacement fields and cable axial total tensions is made.

  15. [Light absorption by suspended particulate matter in Chagan Lake, Jilin].

    Science.gov (United States)

    Wang, Yuan-Dong; Liu, Dian-Wei; Song, Kai-Shan; Zhang, Bai; Wang, Zong-Ming; Jiang, Guang-Ji; Tang, Xu-Guang; Lei, Xiao-Chun; Wu, Yan-Qing

    2011-01-01

    Spectral characteristics and the magnitudes of light absorption by suspended particulate matter were determined by spectrophotometry in this optically complex Lake Chagan waters for the purpose of surveying the natural variability of the absorption coefficients to parameterize the bio-optical models for converting satellite or in-situ water reflectance signatures into water quality information. Experiments were carried out on seasonal frozen Lake Chagan, one representative inland case-2 water body in Northeast of China. Particulate absorption properties analyzed using the field data on July 15th and October 12th 2009 were measured using the quantitative filter technique to produce absorption spectra containing several fractions that could be attributed to two main optical active constituents (OACs) phytoplankton pigments and non-algal particulates (mineral sediments, and organic detritus). Results suggested that the suspended particulate matter (SPM) concentration was higher while phytoplankton biomass (chlorophyll-a concentration) was lower in July and that in October. The spectral shape of total suspended particulate matter resembled that of non-algal particulates which contributed greater than phytoplankton in total particulate absorption during both periods. An obvious absorption peak occurring at around 440 nm exhibited an increase in phytoplankton contribution in October. Non-algal particulate absorption at 440 nm (a(NAP) (440)) had better correlation with total suspended particulate matter concentration than that with chlorophyll-a over the two periods. Light absorption by phytoplankton pigments in the Chagan lake region was generally lower than that of non-algal components. Chl. a dominating phytoplankton pigment composition functioned exponentially with its absorption coefficients at 440 and 675 nm specifically, the average values of which in July were 0.146 8 m2 x mg(-1) and 0.050 3 respectively while in October they were 0.153 3 and 0.013 2 m2 x mg(-1

  16. Development of a microfluidic interface for suspended microchannel resonators

    OpenAIRE

    Maillard, Damien

    2016-01-01

    Suspended microchannel resonators (SMRs) are devices that detect particles in liquid samples. In comparison with similar resonating devices that must be immersed, SMRs allow the fluids to flow through microfluidic resonators. This principle of operation leads to a great reduction of the required sample and to enhanced quality factors. As such, SMRs show great potential for a variety of sensing applications. This thesis reports on the final steps of the microfabrication of SMRs and on the deve...

  17. On the Design of Suspended Roofs with Paraboloidal Surfaces

    Directory of Open Access Journals (Sweden)

    N. Ungureanu

    2006-01-01

    Full Text Available Some considerations concerning the design of the paraboloidal suspended roofs are made. The main geometric aspects are first time presented. For the roofs we propose, as pattern, the equivalent continuum membranes, and the efforts in the cable are determined by using the membrane efforts and their equations. Two examples are analyzed: elliptic paraboloide and hyperbolic paraboloide, with horizontal projection under the form of an ellipse.

  18. Segment Fixed Priority Scheduling for Self Suspending Real Time Tasks

    Science.gov (United States)

    2016-08-11

    for soft real- time systems [15]. Table 1 shows a brief... for execution are the times when a job of task arrives. For 2 ≤ ≤ , when , finishes its execution, it suspends itself for a time duration that lies...assume , and , can take non-negative values such that , ≤ , and let , = , . For each job, a segment , executes for a time duration that lies in

  19. Suspended biofilm carrier and activated sludge removal of acidic pharmaceuticals

    DEFF Research Database (Denmark)

    Falås, Per; Baillon-Dhumez, Aude; Andersen, Henrik Rasmus

    2012-01-01

    Removal of seven active pharmaceutical substances (ibuprofen, ketoprofen, naproxen, diclofenac, clofibric acid, mefenamic acid, and gemfibrozil) was assessed by batch experiments, with suspended biofilm carriers and activated sludge from several full-scale wastewater treatment plants. A distinct...... and attached solids for the carriers) of diclofenac, ketoprofen, gemfibrozil, clofibric acid and mefenamic acid compared to the sludges. Among the target pharmaceuticals, only ibuprofen and naproxen showed similar removal rates per unit biomass for the sludges and biofilm carriers. In contrast...

  20. Chromium in water, suspended particles, sediments and biota in the Iraja River estuary

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, W.C.; Fiszman, M.; de Lacerda, L.D.; van Weerfelt, M.; Carbonell, N.

    1982-11-01

    Analyses of chromium concentrations in waters, suspended particles, bottom sediments, fish (Poecilia reticulata), plants (Paspalum vaginatum, Sesuvium portulacastrum, Philoxeros vermicularis), soils and barnacles (Balanus sp.) were performed from August 1976 to September 1980 in samples collected from the Iraja River and inside its estuary in Guanabara Bay (Rio de Janeiro, Brazil). Sediments and water from the Iraja River showed chromium concentrations of 17536 and 23.39 ppm--a thousand times higher than the published data for freshwater systems. Chromium removed from solution by bottom sediments reaches Guanabara Bay linked to particulate matter. Fish and emergent grass inside the river concentrate chromium from water and/or sediment, returning the metal to the system as detritus. Soil and plants inside the estuary concentrate chromium thirty and ten times higher than in the control area. The vegetal community exhibits a concentration factor smaller than that related to soil and prevents the return of chromium to the estuarine waters. Inside the Guanabara Bay, Balanus sp. appears to be an effective biological monitor as it concentrates chromium in soft tissues 10/sup 3/ times higher than values found in suspended particles (0.012 ..mu..g ml/sup -1/).

  1. Tropical river suspended sediment and solute dynamics in storms during an extreme drought

    Science.gov (United States)

    Clark, Kathryn E.; Shanley, James B.; Scholl, Martha A.; Perdrial, Nicolas; Perdrial, Julia N.; Plante, Alain F.; McDowell, William H.

    2017-05-01

    Droughts, which can strongly affect both hydrologic and biogeochemical systems, are projected to become more prevalent in the tropics in the future. We assessed the effects of an extreme drought during 2015 on stream water composition in the Luquillo Mountains of Puerto Rico. We demonstrated that drought base flow in the months leading up to the study was sourced from trade-wind orographic rainfall, suggesting a resistance to the effects of an otherwise extreme drought. In two catchments (Mameyes and Icacos), we sampled a series of four rewetting events that partially alleviated the drought. We collected and analyzed dissolved constituents (major cations and anions, organic carbon, and nitrogen) and suspended sediment (inorganic and organic matter (particulate organic carbon and particulate nitrogen)). The rivers appeared to be resistant to extreme drought, recovering quickly upon rewetting, as (1) the concentration-discharge (C-Q) relationships deviated little from the long-term patterns; (2) "new water" dominated streamflow during the latter events; (3) suspended sediment sources had accumulated in the channel during the drought flushed out during the initial events; and (4) the severity of the drought, as measured by the US drought monitor, was reduced dramatically after the rewetting events. Through this interdisciplinary study, we were able to investigate the impact of extreme drought through rewetting events on the river biogeochemistry.

  2. Tropical river suspended sediment and solute dynamics in storms during an extreme drought

    Science.gov (United States)

    Clark, Kathryn E.; Shanley, James B.; Scholl, Martha A.; Perdrial, Nicolas; Perdrial, Julia N.; Plante, Alain F.; McDowell, William H.

    2017-01-01

    Droughts, which can strongly affect both hydrologic and biogeochemical systems, are projected to become more prevalent in the tropics in the future. We assessed the effects of an extreme drought during 2015 on stream water composition in the Luquillo Mountains of Puerto Rico. We demonstrated that drought base flow in the months leading up to the study was sourced from trade-wind orographic rainfall, suggesting a resistance to the effects of an otherwise extreme drought. In two catchments (Mameyes and Icacos), we sampled a series of four rewetting events that partially alleviated the drought. We collected and analyzed dissolved constituents (major cations and anions, organic carbon, and nitrogen) and suspended sediment (inorganic and organic matter (particulate organic carbon and particulate nitrogen)). The rivers appeared to be resistant to extreme drought, recovering quickly upon rewetting, as (1) the concentration-discharge (C-Q) relationships deviated little from the long-term patterns; (2) “new water” dominated streamflow during the latter events; (3) suspended sediment sources had accumulated in the channel during the drought flushed out during the initial events; and (4) the severity of the drought, as measured by the US drought monitor, was reduced dramatically after the rewetting events. Through this interdisciplinary study, we were able to investigate the impact of extreme drought through rewetting events on the river biogeochemistry.

  3. Organic matter dynamics and stable isotope signature as tracers of the sources of suspended sediment

    Directory of Open Access Journals (Sweden)

    Y. Schindler Wildhaber

    2012-06-01

    Full Text Available Suspended sediment (SS and organic matter in rivers can harm brown trout Salmo trutta by affecting the health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C, and nitrogen (N during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13Ctot and 15N as input isotopes was used to quantify the temporal and spatial sources of SS. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ13Corg. Organic matter in SS increased from up- to downstream due to an increase of pasture and arable land downstream of the river. The mean fraction of SS originating from upper watershed riverbed sediment decreased from up to downstream and increased during high flow at all measuring sites along the course of the river. During base flow conditions, the major sources of SS are pasture, forest and arable land. The latter increased during rainy and warmer winter periods, most likely because both triggered snow melt and thus erosion. The measured increase in DOC and nitrate concentrations during high flow support these modeling results. Enhanced soil erosion processes on pasture and arable land are expected with increasing heavy rain events and less snow during winter seasons due to climate change. Consequently, SS and organic

  4. Strain sensitivity enhancement in suspended core fiber tapers

    Science.gov (United States)

    André, Ricardo M.; Silva, Susana O.; Becker, Martin; Schuster, Kay; Rothardt, M.; Bartelt, H.; Marques, Manuel B.; Frazão, Orlando

    2013-06-01

    Suspended core fiber tapers with different cross sections (with diameters from 70 μm to 120 μm) are produced by filament heating. Before obtaining the taper, the spectral behavior of the suspended core fiber is a multimode interference structure. When the taper is made, an intermodal interference between a few modes is observed. This effect is clearly visible for low taper core dimensions. Since the core and cladding do not collapse, two taper regions exist, one in the core and the other in the cladding. The cladding taper does not affect the light transmission, only the core is reduced to a microtaper. The spectral response of the microtaper based-suspended core fiber is similar to a beat of two interferometers. The strain is applied to the microtaper, and with the reduction in the transverse area, an increase in sensitivity is observed. When the taper is immersed in a liquid with a different index of refraction or subjected to temperature variations, no spectral change occurs.

  5. Optimal control of suspended sediment distribution model of Talaga lake

    Science.gov (United States)

    Ratianingsih, R.; Resnawati, Azim, Mardlijah, Widodo, B.

    2017-08-01

    Talaga Lake is one of several lakes in Central Sulawesi that potentially to be managed in multi purposes scheme because of its characteristic. The scheme is addressed not only due to the lake maintenance because of its sediment but also due to the Algae farming for its biodiesel fuel. This paper governs a suspended sediment distribution model of Talaga lake. The model is derived from the two dimensional hydrodynamic shallow water equations of the mass and momentum conservation law of sediment transport. An order reduction of the model gives six equations of hyperbolic systems of the depth, two dimension directional velocities and sediment concentration while the bed elevation as the second order of turbulent diffusion and dispersion are neglected. The system is discreted and linearized such that could be solved numerically by box-Keller method for some initial and boundary condition. The solutions shows that the downstream velocity is play a role in transversal direction of stream function flow. The downstream accumulated sediment indicate that the suspended sediment and its changing should be controlled by optimizing the downstream velocity and transversal suspended sediment changing due to the ideal algae growth need.

  6. Abrasion properties of self-suspended hairy titanium dioxide nanomaterials

    Science.gov (United States)

    Zhang, Jiao-xia; Liu, Si; Yan, Chao; Wang, Xiao-jing; Wang, Lei; Yu, Ya-ming; Li, Shi-yun

    2017-10-01

    Considering the excellent solubility of pyrrolidone ring organic compounds, the synthesized N-(trimethoxysilyl) propyl-N-methyl-2-pyrrolidone chlorides was tethered onto titanium dioxide (TiO2) nanoparticles to improve dispersion of TiO2, and then polyethylene oxide (PEO) oligomer through ion exchange embraced the tethered TiO2 to obtain a novel self-suspended hairy TiO2 nanomaterials without any solvent. A variety of techniques were carried out to illustrate the structure and properties of the self-suspended hairy TiO2 nanomaterials. It was found that TiO2 nanoparticles embody monodispersity in the hybrid system though the "false reunion" phenomenon occurring due to nonpermanent weak physical cross-linking. Remarkably, self-suspended hairy TiO2 nanomaterials exhibit lower viscosity, facilitating maneuverable and outstanding antifriction and wear resistance properties, due to the synergistic lubricating effect between spontaneously forming lubricating film and nano-lubrication of TiO2 cores, overcoming the deficiency of both solid and liquid lubricants. This make them promising candidates for the micro-electromechanic/nano-electromechanic systems (MEMS/NEMS).

  7. Assessment of the caesium-137 flux adsorbed to suspended sediment in a reservoir in the contaminated Fukushima region in Japan.

    Science.gov (United States)

    Mouri, Goro; Golosov, Valentin; Shiiba, Michiharu; Hori, Tomoharu

    2014-04-01

    We estimated the flux of caesium-137 adsorbed to suspended sediment in the Kusaki Dam reservoir in the Fukushima region of eastern Japan, which was contaminated by the Fukushima Nuclear Power Plant accident. The amount and rate of reservoir sedimentation and the caesium-137 concentration were validated based on the mixed-particle distribution and a sediment transport equation. The caesium-137 and sediment flux data suggested that wash load, suspended load sediment, and caesium-137 were deposited and the discharge and transport processes generated acute pollution, especially during extreme rainfall-runoff events. Additionally, we qualitatively assessed future changes in caesium-137 and sediment fluxes in the reservoir. The higher deposition and discharge at the start of the projection compared to the 2090s are most likely explained by the radioactive decay of caesium-137 and the effects of reservoir sedimentation. Predictions of the impacts of future climate on sediment and caesium-137 fluxes are crucial for environmental planning and management. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Field evaluation of the error arising from inadequate time averaging in the standard use of depth-integrating suspended-sediment samplers

    Science.gov (United States)

    Topping, David J.; Rubin, David M.; Wright, Scott A.; Melis, Theodore S.

    2011-01-01

    Several common methods for measuring suspended-sediment concentration in rivers in the United States use depth-integrating samplers to collect a velocity-weighted suspended-sediment sample in a subsample of a river cross section. Because depth-integrating samplers are always moving through the water column as they collect a sample, and can collect only a limited volume of water and suspended sediment, they collect only minimally time-averaged data. Four sources of error exist in the field use of these samplers: (1) bed contamination, (2) pressure-driven inrush, (3) inadequate sampling of the cross-stream spatial structure in suspended-sediment concentration, and (4) inadequate time averaging. The first two of these errors arise from misuse of suspended-sediment samplers, and the third has been the subject of previous study using data collected in the sand-bedded Middle Loup River in Nebraska. Of these four sources of error, the least understood source of error arises from the fact that depth-integrating samplers collect only minimally time-averaged data. To evaluate this fourth source of error, we collected suspended-sediment data between 1995 and 2007 at four sites on the Colorado River in Utah and Arizona, using a P-61 suspended-sediment sampler deployed in both point- and one-way depth-integrating modes, and D-96-A1 and D-77 bag-type depth-integrating suspended-sediment samplers. These data indicate that the minimal duration of time averaging during standard field operation of depth-integrating samplers leads to an error that is comparable in magnitude to that arising from inadequate sampling of the cross-stream spatial structure in suspended-sediment concentration. This random error arising from inadequate time averaging is positively correlated with grain size and does not largely depend on flow conditions or, for a given size class of suspended sediment, on elevation above the bed. Averaging over time scales >1 minute is the likely minimum duration required

  9. Intelligent Models Performance Improvement Based on Wavelet Algorithm and Logarithmic Transformations in Suspended Sediment Estimation

    Directory of Open Access Journals (Sweden)

    R. Hajiabadi

    2016-10-01

    Full Text Available Introduction One reason for the complexity of hydrological phenomena prediction, especially time series is existence of features such as trend, noise and high-frequency oscillations. These complex features, especially noise, can be detected or removed by preprocessing. Appropriate preprocessing causes estimation of these phenomena become easier. Preprocessing in the data driven models such as artificial neural network, gene expression programming, support vector machine, is more effective because the quality of data in these models is important. Present study, by considering diagnosing and data transformation as two different preprocessing, tries to improve the results of intelligent models. In this study two different intelligent models, Artificial Neural Network and Gene Expression Programming, are applied to estimation of daily suspended sediment load. Wavelet transforms and logarithmic transformation is used for diagnosing and data transformation, respectively. Finally, the impacts of preprocessing on the results of intelligent models are evaluated. Materials and Methods In this study, Gene Expression Programming and Artificial Neural Network are used as intelligent models for suspended sediment load estimation, then the impacts of diagnosing and logarithmic transformations approaches as data preprocessor are evaluated and compared to the result improvement. Two different logarithmic transforms are considered in this research, LN and LOG. Wavelet transformation is used to time series denoising. In order to denoising by wavelet transforms, first, time series can be decomposed at one level (Approximation part and detail part and second, high-frequency part (detail will be removed as noise. According to the ability of gene expression programming and artificial neural network to analysis nonlinear systems; daily values of suspended sediment load of the Skunk River in USA, during a 5-year period, are investigated and then estimated.4 years of

  10. Seasonal changes, spatial variability and origin of suspended organic matter in Hornsund, Spitsbergen

    Science.gov (United States)

    Apolinarska, Karina; Szczuciński, Witold; Moskalik, Mateusz; Dominiczak, Aleksander

    2017-04-01

    Carbon stable isotope composition (δ13C) of suspended organic matter (SOM) was investigated to recognize temporal and spatial variability, as well as sources of particulate carbon delivered to the sediments of Hornsund fjord, Spitsbergen. Sampling was carried out between May 2015, when most of the investigated area was covered with sea-ice, and late August 2015. Samples were taken from a number of sites in central part of Hornsund, Burgerbukta, Samarinvegen and Brepolen bay in the innermost part of the fjord. One litre water volume, sampled from a range of depths between the water surface and 100 m, was filtered using GFF filters. δ13C values of the SOM were measured after acid treatment of the filters to remove carbonates. δ13C values of SOM varied both temporarily and spatially reflecting the variable sources of organic carbon, namely the marine production in situ, fresh marine organic carbon brought from the shelf with currents and "old" carbon delivered from land. The samples were most 13C-enriched (-22.4‰) in June, at the time of an intensive primary productivity within the fjord. Later, during the warm season, with the more intensive glaciers melting and thus supply of the suspended sediment load containing the old terrigenous carbon, δ13C values of SOM decreased in all the localities studied towards the carbon isotope values of the local terrestrial end-member, i.e., δ13C values of the old organic carbon in the bedrock. Change in δ13C values of SOM was also observed with increasing distance from glaciers, e.g. in front of the Samarinbreen and reflect changes in the intensity of primary production and supply of the old carbon. The study was supported from National Science Center grant No. 2013/10/E/ST10/00166.

  11. Viruses, bacteria and suspended particles in a backwater and main channel site of the Danube (Austria)

    Science.gov (United States)

    Peduzzi, Peter; Luef, Birgit

    2010-01-01

    A short overview of currently available studies on the ecology of viruses in running waters is provided. Additionally, a survey was conducted on the dynamics of both viruses and bacteria in an isolated floodplain segment of the Danube River and in the main channel near Vienna (Austria) during the hydrologically most dynamic phase (spring – summer). The study evaluates the differences between the main channel and the floodplain segment for suspended particle abundance and quality in relation to bacterial and viral parameters; both free-living forms and those attached to particles are examined. The hydrological disconnection of these two contrasting sampling sites influenced particle abundance and quality as well as the distribution of free-living vs. attached bacteria and viruses. The per-cell activity of bacteria attached to particles was significantly higher than that of the free-living fraction, particularly in the isolated water body. The abundance of bacteria and viruses on particles depended on particle quality (size). In the main channel, bacteria were significantly more abundant on surfaces (per mm2) of suspended matter > 5 μm (aggregates with organic constituents) compared to particles 5μm and attached viruses; free-living viruses were less abundant at high > 5μm particle loads. Only in the isolated floodplain section was viral abundance positively influenced by elevated per-cell productivity of potential host bacteria. The results demonstrate that system variability on a relatively small topographical scale (within a river-floodplain system) has consequences for microbial life, including viruses. PMID:21151810

  12. How are River Discharge - Suspended Sediment Relations Influenced by Watershed and Channel-Floodplain Morphology?

    Science.gov (United States)

    Vaughan, A. A.; Belmont, P.

    2015-12-01

    Erosion, transport and deposition of fine sediment (clay, silt and fine sand) influence the form and function of river systems. Excess suspended sediment degrades stream ecosystems and is implicated as a leading cause of water quality and aquatic life impairment. Consequently, understanding the factors that control fine sediment transport regimes is an interesting topic for basic science and one that has important management and policy implications. Fine sediment is mostly transported in suspension as a non-capacity load; transport rates are dependent on sediment supply in addition to a river's transport capacity. Many studies have investigated watershed-scale topographic, hydrologic, climatic, and land use influences on fine sediment erosion and transport regimes. Several recent studies in a wide range of landscapes have demonstrated that the majority of suspended sediment may be sourced from the near-channel environment; therefore, near-channel morphological characteristics may provide better predictive power compared to watershed averages. This study analyzes recent total suspended solids (TSS) data from 45 gages on 35 separate rivers. The rivers span the state of Minnesota, draining basins ranging from 33 km2 to 68100 km2 with distinct settings in terms of topography, land cover, hydrology and geologic history. We generate rating curves of the form TSS = aQb, where Q is normalized discharge and a and b are parameters that describe the shape of the relations. Values of a range from 4 to 138 mg/L; b values range from -0.53 to 1.86. We use high resolution lidar topography data to characterize the near-channel environment upstream of gages. In addition to commonly studied metrics describing the topographic, climatic/hydrologic and land use setting of the basin, we extract near-channel morphometrics that we hypothesize to influence fine sediment generation and transport: the difference in height of banks/bluffs (a measure of the amount of material available to be

  13. Load testing circuit

    DEFF Research Database (Denmark)

    2009-01-01

    A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...

  14. Regression modeling of particle size distributions in urban storm water: advancements through improved sample collection methods

    Science.gov (United States)

    Fienen, Michael N.; Selbig, William R.

    2012-01-01

    A new sample collection system was developed to improve the representation of sediment entrained in urban storm water by integrating water quality samples from the entire water column. The depth-integrated sampler arm (DISA) was able to mitigate sediment stratification bias in storm water, thereby improving the characterization of suspended-sediment concentration and particle size distribution at three independent study locations. Use of the DISA decreased variability, which improved statistical regression to predict particle size distribution using surrogate environmental parameters, such as precipitation depth and intensity. The performance of this statistical modeling technique was compared to results using traditional fixed-point sampling methods and was found to perform better. When environmental parameters can be used to predict particle size distributions, environmental managers have more options when characterizing concentrations, loads, and particle size distributions in urban runoff.

  15. Effect of Organic Loading on Rotating Biological Contactor Efficiency

    Directory of Open Access Journals (Sweden)

    Kossay K. Al-Ahmady

    2005-12-01

    Full Text Available Organic loading (weight per unit time per volume is useful for the design of rotating biological contactors (RBC and for comparison with the other processes such as activated sludge or oxidation ponds. The present study puts emphasis on the significance of this control or design parameter because it allows direct comparison of the RBC system's performance when operated under various circumstances and with different kinds of wastewater. The results of the paper proved that, the COD removal in rotating biological contactor systems is a function of the organic loading rate. However, each of the wastewater concentration and flow rate are also influence on the system efficiency but theirs impact can be combined by the effect of organic loading. The majority of COD removal (40-85 % of the total removal depending on the organic loading applied occurs in the first stages of the system. There is a strong correlation between the organic loading and the concentration of the suspended solids in the rotating biological contactor basin. At higher loadings higher concentrations noted. At a loading of about, (24 g/m2.d suspended solids were 225, 125, 35, and 25 mg/L in the first, second, third and, the fourth stage respectively. To achieve an effluent quality of (BOD < 25 mg/L, COD < 60 mg/L, the system must be operated on organic loadings of about (22 gBOD/m2.d and 65 gCOD/m2.d respectively. For nitrification process, the system must be designed to operate at organic loading of about (10 g/m2.d or less and, the reactor or basin volume should be designed to achieve a hydraulic loading of about (40 L/m2.d or less.

  16. Nutrient and Suspended-Sediment Transport and Trends in the Columbia River and Puget Sound Basins, 1993-2003

    Science.gov (United States)

    Wise, Daniel R.; Rinella, Frank A.; Rinella, Joseph F.; Fuhrer, Greg J.; Embrey, Sandra S.; Clark, Gregory M.; Schwarz, Gregory E.; Sobieszczyk, Steven

    2007-01-01

    This study focused on three areas that might be of interest to water-quality managers in the Pacific Northwest: (1) annual loads of total nitrogen (TN), total phosphorus (TP) and suspended sediment (SS) transported through the Columbia River and Puget Sound Basins, (2) annual yields of TN, TP, and SS relative to differences in landscape and climatic conditions between subbasin catchments (drainage basins), and (3) trends in TN, TP, and SS concentrations and loads in comparison to changes in landscape and climatic conditions in the catchments. During water year 2000, an average streamflow year in the Pacific Northwest, the Columbia River discharged about 570,000 pounds per day of TN, about 55,000 pounds per day of TP, and about 14,000 tons per day of SS to the Pacific Ocean. The Snake, Yakima, Deschutes, and Willamette Rivers contributed most of the load discharged to the Columbia River. Point-source nutrient loads to the catchments (almost exclusively from municipal wastewater treatment plants) generally were a small percentage of the total in-stream nutrient loads; however, in some reaches of the Spokane, Boise, Walla Walla, and Willamette River Basins, point sources were responsible for much of the annual in-stream nutrient load. Point-source nutrient loads generally were a small percentage of the total catchment nutrient loads compared to nonpoint sources, except for a few catchments where point-source loads comprised as much as 30 percent of the TN load and as much as 80 percent of the TP load. The annual TN and TP loads from point sources discharging directly to the Puget Sound were about equal to the annual loads from eight major tributaries. Yields of TN, TP, and SS generally were greater in catchments west of the Cascade Range. A multiple linear regression analysis showed that TN yields were significantly (p < 0.05) and positively related to precipitation, atmospheric nitrogen load, fertilizer and manure load, and point-source load, and were negatively

  17. Influence of land use on total suspended solid and dissolved ion concentrations: Baton Rouge, Louisiana area

    Directory of Open Access Journals (Sweden)

    D. Carlson

    2015-03-01

    Full Text Available Past studies in the Baton Rouge, Louisiana area considered streamwater quality during storm events but ignored water quality during low flow periods. This study includes determination of streamwater quality during low flow time periods for none watersheds in East Baton Rouge Parish, Louisiana. These samples were collected during dry-low flow periods as indicated by water levels at USGS stream gauging sites for each stream. Chemical analysis for ions was completed using colorimeters and gravimetric analysis for total dissolved solids (TDS and total suspended solids (TSS. Land use appears to impact concentrations of ions, TDS and TSS in a variety of ways during periods of low flow. The two most rural watersheds, which are mainly underdeveloped, have higher concentrations of Fe and Mn. By contrast the three most urban watersheds, that are mainly commercial, industrial or residential, have higher concentrations of Si, SO4 and TDS.

  18. Overview of selected surrogate technologies for high-temporal resolution suspended-sediment monitoring

    Science.gov (United States)

    Gray, John R.; Gartner, Jeffrey W.

    2010-01-01

    Traditional methods for characterizing selected properties of suspended sediments in rivers are being augmented and in some cases replaced by cost-effective surrogate instruments and methods that produce a temporally dense time series of quantifiably accurate data for use primarily in sediment-flux computations. Turbidity is the most common such surrogate technology, and the first to be sanctioned by the U.S. Geological Survey for use in producing data used in concert with water-discharge data to compute sediment concentrations and fluxes for storage in the National Water Information System. Other technologies, including laser-diffraction, digital photo-optic, acoustic-attenuation and backscatter, and pressure-difference techniques are being evaluated for producing reliable sediment concentration and, in some cases, particle-size distribution data. Each technology addresses a niche for sediment monitoring. Their performances range from compelling to disappointing. Some of these technologies have the potential to revolutionize fluvial-sediment data collection, analysis, and availability.

  19. Distributed dynamic load on composite laminates

    Science.gov (United States)

    Langella, A.; Lopresto, V.; Caprino, G.

    2016-05-01

    An experimental activity conducted in order to assess the impact behavior at room and low temperature of carbon fibre in vinylester resin laminates used in the shipbuilding industry, was reported. The conditions which reproduce the impact of a hull at low temperature with a solid body suspended in the water was reproduced. A test equipment was designed and realized to reproduce the real material behaviour in water to obtain a load distribution on the entire surface of the specimen. The results were obtained impacting the laminates placed between the cilyndrical steel impactor and a bag containing water. A falling weight machine, equipped with an instrumented steel impactor and a thermal chamber, was adopted for the experimental tests. The impact behaviour in hostile environments was compared to the behaviour at room temperature and the data obtained under distributed load conditions were compared with the results from concentrated loads: a completely different behaviour was observed between the two different loading conditions in terms of load-displacement curve. The effect of the impact on the laminates has been related with the delaminations, evaluated by ultrasonic scanning, and the indentation.

  20. Use of an ADCP to compute suspended-sediment discharge in the tidal Hudson River, New York

    Science.gov (United States)

    Wall, Gary R.; Nystrom, Elizabeth A.; Litten, Simon

    2006-01-01

    Acoustic Doppler current profilers (ADCPs) can provide data needed for computation of suspended-sediment discharge in complex river systems, such as tidal rivers, in which conventional methods of collecting time-series data on suspended-sediment concentration (SSC) and water discharge are not feasible. Although ADCPs are not designed to measure SSC, ADCP data can be used as a surrogate under certain environmental conditions. However, the software for such computation is limited, and considerable post-processing is needed to correct and normalize ADCP data for this use. This report documents the sampling design and computational procedure used to calibrate ADCP measures of echo intensity to SSC and water velocity to discharge in the computation of suspended-sediment discharge at the study site on the Hudson River near Poughkeepsie, New York. The methods and procedures described may prove useful to others doing similar work in different locations; however, they are specific to this study site and may have limited applicability elsewhere.

  1. Particle size distribution of river-suspended sediments determined by in situ measured remote-sensing reflectance.

    Science.gov (United States)

    Zhang, Yuanzhi; Huang, Zhaojun; Chen, Chuqun; He, Yijun; Jiang, Tingchen

    2015-07-10

    Suspended sediments in water bodies are classified into organic and inorganic matter and have been investigated by remote-sensing technology for years. Focusing on inorganic matter, however, detailed information such as the grain size of this matter has not been provided yet. In this study, we present a new solution for estimating inorganic suspended sediments' size distribution in highly complex Case 2 waters by using a simple spectrometer sensor rather than a backscattering sensor. An experiment was carried out in the Pearl River Estuary (PRE) in the dry season to collect the remote-sensing reflectance (Rrs) and particle size distribution (PSD) of inorganic suspended sediments. Based on Mie theory, PSDs in the PRE waters were retrieved by Rrs, colored dissolved organic matter, and phytoplankton. The retrieved median diameters in 12 stations show good agreement with those of laboratory analysis at root mean square error of 2.604 μm (27.63%), bias of 1.924 μm (20.42%), and mean absolute error of 2.298 μm (24.37%). The retrieved PSDs and previous PSDs were compared, and the features of PSDs in the PRE waters were concluded.

  2. Trace Elemental Analyses of Suspended Sediments in the San Francisco Estuary and its Tidal Marshes

    Science.gov (United States)

    Malamud-Roam, F. P.; Ingram, B. L.; Yang, W.; Collins, J.

    2004-12-01

    This research evaluates the trace elemental compositions of inorganic sediments in the San Francisco Bay estuary marshes over space and time. These sediments create and maintain the tidal marshes that surround the Sand Francisco Bay, yet a thorough analysis of the sources of these sediments remains understudied. Determining the sources of sediments is of interest because current mitigation and restoration projects around the Bay must consider whether the sediment supply will be sufficient for projects, or if opening diked wetlands to tidal flow will result in salt water intrusion further up-estuary (into the Delta). Results of trace element analyses of suspended sediments that pass through the Sacramento-San Joaquin Delta (the Delta) are compared with those of local watershed tributaries. Differences in bedrock lithology can be seen in the varying trace elemental concentrations; for example, K, Nd, Sm, Rb and Sr concentrations are significantly lower in the Sacramento river sediments than those of the San Joaquin river and can be used to differentiate further the Delta input. Results from marsh surface samples throughout the North Bay and preliminary results from 4 1-m long sediment cores collected along a transect of the Novato creek marsh (NCM) reflect local versus Delta sediment source patterns. The suspended sediment samples from the Sacramento and San Joaquin rivers and from local creeks reflect the end members of the sediment supply for local marshes. The marsh surface samples represent the most recent period (last few years or so) and reflect the extent of Delta influence into the estuary. Finally, the cores collected from the Novato creek marsh provide details on the gradient of dominant source supply (i.e., are the sediments well inland predominantly from the local watershed and how far does that influence extend downstream), as well as a history of how the sediment supply conditions have changed, comparing pre-Gold Rush and agriculture era (before about

  3. Intergrating cavity absorption meter measurements of dissolved substances and suspended particles in ocean water

    Science.gov (United States)

    Pope, Robin M.; Weidemann, Alan D.; Fry, Edward S.

    2000-01-01

    We have developed a new device to measure the separate contributions to the spectral absorption coefficient due to a pure liquid, due to the particles suspended in it, and due to the substances dissolved in it. This device, the Integrating Cavity Absorption Meter (ICAM), is essentially independent of scattering effects in the sample. In April 1993, a prototype of the ICAM was field tested on board the research vessel USNS Bartlett. A major part of the cruise track included criss-crossing the area where the Mississippi flows into the Gulf of Mexico at various ranges from the mouth of the river; thus samples were collected from areas of blue, green, and brown/black water. We evaluated 35 seawater samples collected with 5-l Niskin bottles from 22 locations to determine absorption spectra (380-700 nm) of suspended particles and dissolved substances (gelbstoff). Results validate the ICAM as a viable tool for marine optical absorption research. Gelbstoff absorption at 432.5 nm ranged from 0.024 to 0.603 m -1. Over the spectral region 380→560 nm, gelbstoff absorption by each of the samples could be accurately fit to a decaying exponential. The particle absorption spectra are generally characteristic of those of phytoplankton and exhibit a local maximum at 430-440 nm. Absorption values at 432.5 nm ranged from ˜zero to ˜1.0 m -1. Some samples with moderate particulate absorption, however, did not show the characteristic local maximum of phytoplankton in the blue and instead resembled the characteristic decaying exponential of detritus with a shape similar to that observed in the gelbstoff. The ratio of gelbstoff to particulate absorption at 432.5 nm ranged from 0.46 to 152.

  4. Surface-enhanced Raman scattering of suspended monolayer graphene

    Science.gov (United States)

    Huang, Cheng-Wen; Lin, Bing-Jie; Lin, Hsing-Ying; Huang, Chen-Han; Shih, Fu-Yu; Wang, Wei-Hua; Liu, Chih-Yi; Chui, Hsiang-Chen

    2013-11-01

    The interactions between phonons and electrons induced by the dopants or the substrate of graphene in spectroscopic investigation reveal a rich source of interesting physics. Raman spectra and surface-enhanced Raman spectra of supported and suspended monolayer graphenes were measured and analyzed systemically with different approaches. The weak Raman signals are greatly enhanced by the ability of surface-enhanced Raman spectroscopy which has attracted considerable interests. The technique is regarded as wonderful and useful tool, but the dopants that are produced by depositing metallic nanoparticles may affect the electron scattering processes of graphene. Therefore, the doping and substrate influences on graphene are also important issues to be investigated. In this work, the peak positions of G peak and 2D peak, the I 2D/ I G ratios, and enhancements of G and 2D bands with suspended and supported graphene flakes were measured and analyzed. The peak shifts of G and 2D bands between the Raman and SERS signals demonstrate the doping effect induced by silver nanoparticles by n-doping. The I 2D/ I G ratio can provide a more sensitive method to carry out the doping effect on the graphene surface than the peak shifts of G and 2D bands. The enhancements of 2D band of suspended and supported graphenes reached 138, and those of G band reached at least 169. Their good enhancements are helpful to measure the optical properties of graphene. The different substrates that covered the graphene surface with doping effect are more sensitive to the enhancements of G band with respect to 2D band. It provides us a new method to distinguish the substrate and doping effect on graphene.

  5. The effect of source suspended sediment concentration on the sediment dynamics of a macrotidal creek and salt marsh

    Science.gov (United States)

    Poirier, Emma; van Proosdij, Danika; Milligan, Timothy G.

    2017-09-01

    Seasonal variability in the sediment dynamics of a Bay of Fundy tidal creek and salt marsh system was analyzed to better understand the ecomorphodynamics of a high suspended sediment concentration intertidal habitat. Data were collected over 62 tides for velocity, suspended sediment concentration, deposition, and grain size at four stations from the creek thalweg to the marsh surface. Five topographic surveys were also conducted throughout the 14-month study. Deposition rates per tide varied spatially from 56.4 g m-2 at the creek thalweg to 15.3 g m-2 at the marsh surface. Seasonal variations in deposition in the creek and marsh surface were from 38.0 g m-2 to 97.7 g m-2 and from 12.2 g m-2 to 19.6 g m-2 respectively. Deposition and erosion were greatest in late fall and winter. This seasonal change, led by higher suspended sediment concentrations, was observed in the creek and at the marsh bank but notably absent from the marsh edge and marsh surface. Sediments were predominantly deposited in floc form (76-83%). Because of high floc content, higher suspended sediment concentrations led to more rapid loss of sediment from suspension. With increasing sediment concentration, deposition increased in the tidal creek and at the marsh bank but not at the marsh edge or marsh surface. This suggests that in highly flocculated environments the water column clears fast enough that very little sediment remains in suspension when the water reaches the marsh and that the sediment concentration during marsh inundation is independent of the initial concentration in the creek.

  6. Coupling between electronic transport and longitudinal phonons in suspended nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sapmaz, S; Jarillo-Herrero, P; Blanter, Ya M; Zant, H S J van der [Kavli Institute of Nanoscience, Delft University of Technology, PO Box 5046, 2600 GA Delft (Netherlands)

    2005-11-15

    Current-voltage characteristics of suspended single-wall carbon nanotube (NT) quantum dots show a series of steps equally spaced in voltage. The energy scale of this harmonic, low-energy excitation spectrum is consistent with that of the longitudinal low-k phonon mode in the NT. Agreement is found with a Franck-Condon-based model in which the phonon-assisted tunnelling process is modelled as a coupling of electronic levels to underdamped quantum harmonic oscillators. Comparison with this model indicates a rather strong electron-phonon coupling factor of order unity. We investigate different electron-phonon coupling mechanisms and give estimates of the coupling factor.

  7. Regional volume changes in canine lungs suspended in air

    Science.gov (United States)

    Abbrecht, Peter H.; Kyle, Richard R.; Bryant, Howard J.; Feuerstein, Irwin

    1995-01-01

    The purpose of this study was to determine the effect of the absence of a pleural pressure gradient (simulating the presumed condition found in microgravity) upon regional expansion of the lung. We attempted to produce a uniform pressure over the surface of the lung by suspending excised lungs in air. Such studies should help determine whether or not the absence of a pleural pressure gradient leads to uniform ventilation. A preparation in which there is no pleural pressure gradient should also be useful in studying non-gravitational effects on ventilation distribution.

  8. The Ages in a Self-Suspended Nanoparticle Liquid

    KAUST Repository

    Agarwal, Praveen

    2010-01-13

    Telomers ionically tethered to nanometer-sized particles yield self-suspended, nanoparticle-Iaden liquids with unusual dynamical features. By subjecting these suspensions to controlled, modest shear strains, we find that their flow behaviors observed using experiments performed on time scales of tens of seconds can be projected to obtain maps of their dynamical response on geological time scales. That such extraordinarily slow dynamic processes can be uncovered from real-time measurements by simply stretching a system provides a simple but powerful tool for interrogating extremely slow motions in other jammed physical states. © 2010 American Chemical Society.

  9. Suspended liminality: Vacillating affects in cyberbullying/research

    OpenAIRE

    Kofoed, J.; Stenner, Paul

    2017-01-01

    This paper develops a concept of liminal hotspots in the context of i) a secondary analysis of a cyberbullying case involving a group of school children from a Danish school, and ii) an altered auto-ethnography in which the authors ‘entangle’ their own experiences with the case analysis. These two sources are used to build an account of a liminal hotspot conceived as an occasion of troubled and suspended transformative transition in which a liminal phase is extended and remains unresolved. Th...

  10. Oscillation of a diamagnetic liquid bubble suspended by magnetic force

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, R. E-mail: yamane@kokushikan.ac.jp; Tomita, S.; Mai, J.; Park, M.K.; Oshima, S

    2002-11-01

    The levitation of the diamagnetic liquid droplet with the strong magnetic field is experimentally simulated, using the magnetic fluid as the surrounding fluid in place of air or gas, and the water bubble is levitated with the conventional permanent magnet. When the stepwise magnetic field is superposed, the suspended bubble behaves as a typical step response with the overshoot and viscous damping. The effects of the volume of the bubble, the strength of the magnetic field and the concentration of the magnetic fluid are investigated.

  11. Evaluation of sediment yield and sediment data-collection network in the Piceance basin, northwestern Colorado

    Science.gov (United States)

    Kircher, J.E.; Von Guerard, Paul

    1982-01-01

    Statistical relationships were developed between suspended-sediment discharge and several regional factors of climate, physiography, and land use in the Piceance basin, northwestern Colorado. The purpose of the study was to evaluate the existing sediment collection network, especially in regard to detecting changes in suspended-sediment discharge due to the development in the basin. Spatial- and time variability were examined using multiple linear regression techniques. Because of the short period of record, monthly mean sediment loads were used to determine shifts or changes in trends due to mining and related activities in the basin. Dummy variable analysis was used to detect these premining and postmining differences in the regression lines and also to detect seasonal differences in the sediment discharge. Differences did exist in the sediment discharge from season to season and before and after mining; however, due to the variability and short period of record the cause of these differences could not be adequately determined. Part of the high variability in sediment discharge was due to variability in the water discharge. Therefore, if the network is to be improved, the emphasis needs to be on improvement of the water-discharge. The results of the monthly mean regression analysis were used in the mean monthly and mean annual analysis for determination of initial network design equations. These were only preliminary in nature and could be improved with additional data. (USGS)

  12. Remote Sensing Studies of Suspended Sediment Concentration Variation in Barito Delta

    Science.gov (United States)

    Arisanty, Deasy; Nur Saputra, Aswin

    2017-12-01

    The dynamic of suspended sediment concentration in Barito Delta depend on the process in upstream. Agriculture, mining, and illegal logging in Barito River upstream has an effect for suspended sediment concentration in Barito Delta. The objective of research is to estimate the variation of suspended sediment concentration in Barito Delta. The data of research consist of Landsat 7 in year 2011 and measurement result data of suspended sediment concentration both in wet season and dry season in year 2011. Data analysis is regression analysis to estimates the variation of suspended sediment concentration in Barito Delta. The method of research compares three types of spectral transformation for suspended sediment that is Normalized Suspended Material Index (NSMI), Normalized Differences Suspended Sediment Index (NDSSI), and band ratio (green/blue). The result of the transformation is compared with the value of the field measurement. Based on the result of the comparison can be known the suitable type of transformation for the suspended sediment estimation in Barito Delta. The result of research explains that NSMI has the highest value to estimate the variation of suspended sediment concentration in Barito Delta.

  13. Nutrient and metal loads estimated by using discrete, automated, and continuous water-quality monitoring techniques for the Blackstone River at the Massachusetts-Rhode Island State line, water years 2013–14

    Science.gov (United States)

    Sorenson, Jason R.; Granato, Gregory E.; Smith, Kirk P.

    2018-01-10

    Flow-proportional composite water samples were collected in water years 2013 and 2014 by the U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, from the Blackstone River at Millville, Massachusetts (U.S. Geological Survey station 01111230), about 0.5 mile from the border with Rhode Island. Samples were collected in order to better understand the dynamics of selected nutrient and metal constituents, assist with planning, guide activities to meet water-quality goals, and provide real-time water-quality information to the public. An automated system collected the samples at 14-day intervals to determine total and dissolved nitrogen and phosphorus concentrations, to provide accurate monthly nutrient concentration data, and to calculate monthly load estimates. Concentrations of dissolved trace metals and total aluminum were determined from 4-day composite water samples that were collected twice monthly by the automated system. Results from 4-day composites provide stakeholders with information to evaluate trace metals on the basis of chronic 4-day exposure criteria for aquatic life, and the potential to use the biotic ligand model to evaluate copper concentrations. Nutrient, trace metal, suspended sediment, dissolved organic carbon, and chlorophyll a concentrations were determined from discrete samples collected at the Millville station and from across the stream transect at the upstream railroad bridge, and these concentrations served as a means to evaluate the representativeness of the Millville point location.Analytical results from samples collected with the automated flow-proportional sampling system provided the means to calculate monthly and annual loading data. Total nitrogen and total phosphorus loads in water year (WY) 2013 were about 447,000 and 36,000 kilograms (kg), respectively. In WY 2014, annual loads of total nitrogen and total phosphorus were about 342,000 and 21,000 kg, respectively. Total nitrogen

  14. Electrical load detection aparatus

    DEFF Research Database (Denmark)

    2010-01-01

    A load detection technique for a load comprising multiple frequency-dependant sub-loads comprises measuring a representation of the impedance characteristic of the load; providing stored representations of a multiplicity of impedance characteristics of the load; each one of the stored representat...

  15. Contribution of food availability to the more rapid growth of the scallop, Euvola ziczac (Pteroida, Pectinidae in bottom than in suspended culture

    Directory of Open Access Journals (Sweden)

    Patrick Hunauld

    2005-09-01

    Full Text Available We conducted a 5-month experiment at Turpialito in the Golfo de Cariaco, Venezuela, to examine whether the previously reported more rapid growth of scallop Euvola ziczac in bottom compared to suspended culture can be attributed to more abundant or higher quality food resources near the sediment/water interface. The various body components (shell, muscle, digestive gland, gonad and remaining tissues increased in size at a much greater rate for scallops maintained on the bottom, in partly buried cages at 5 m in depth, than in cages suspended at the same depth in the water column. Furthermore, survival was greater on the bottom. Food abundance and quality were examined by analyzing the seston collected in sediment traps at the sediment/water interface in the vicinity of the bottom cages and next to the suspended cages. Phytoplankton abundance (chlorophyll a and the proportion of various fatty acids in the lipid fraction of the seston were similar on the bottom and in suspension. However, sestonic protein, lipid and carbohydrate levels, and the estimated energetic content of the seston, were higher on the bottom than in suspension, and probably contributed to the greater growth on the bottom. As the increase in the energetic content of the seston on the bottom compared to in suspension was less than the increase in growth (biomass on the bottom compared to in suspension, and the evidence showed in previous studies above the negative influence of fouling and wave action in suspended culture, we conclude that the more rapid growth of Euvola ziczac in bottom than suspended culture is principally due to stress relative to suspended culture system. Rev. Biol. Trop. 53(3-4: 455-461. Epub 2005 Oct 3.

  16. Changes in contaminant loading and hydro-chemical storm behavior after the Station Fire

    Science.gov (United States)

    Burke, M. P.; Hogue, T. S.; Barco, J.; Wessel, C. J.

    2010-12-01

    The 2009 Station Fire, currently noted as the largest fire in Los Angeles County history, consumed over 650 square kilometers of National Forest land in the San Gabriel Mountain Range. These mountains, located on the east side (leeward) of the Los Angeles basin, are known to have some of the highest deposition rates of atmospheric pollutants in the nation. Even pre-fire, urban-fringe basins in this mountain range serve as an upstream source of contaminants to downstream urban streams. Burned watersheds undergo significant physical and chemical changes that dramatically alter hydrologic flowpaths, erosion potential, surface soil chemistry, and pollutant delivery. Much of the degradation in water quality is attributed to the extensive soil erosion during post-fire runoff events which carry large sediment loads, mobilizing and transporting contaminants to and within downstream waters. High resolution storm samples collected from a small front range watershed provide a unique opportunity to investigate the impacts of wildfire contaminant loading in a watershed that is significantly impacted by high atmospheric deposition of urban contaminates. Data includes four events from WY 2009 (pre-fire) and WY 2010 (post-fire), along with inter-storm grab samples from each storm season. Samples were analyzed for basic anions, nutrients, trace metals, and total suspended solids. Following the fire, storms with similar precipitation patterns yielded loads up to three orders of magnitude greater than pre-fire for some toxic metals, including lead and cadmium. Dramatic increases were also observed in trace metal concentrations typically associated with particulates, while weathering solute concentrations decreased. Post fire intra-storm dynamics exhibited a shift back toward pre-fire behavior by the end of the first rainy season for most of the measured constituents. Additionally, some unexpected behaviors were observed; specifically mercury loads continued to increase throughout the

  17. Assessment of conservation easements, total phosphorus, and total suspended solids in West Fork Beaver Creek, Minnesota, 1999-2012

    Science.gov (United States)

    Christensen, Victoria G.; Kieta, Kristen A.

    2014-01-01

    This study examined conservation easements and their effectiveness at reducing phosphorus and solids transport to streams. The U.S. Geological Survey cooperated with the Minnesota Board of Water and Soil Resources and worked collaboratively with the Hawk Creek Watershed Project to examine the West Fork Beaver Creek Basin in Renville County, which has the largest number of Reinvest In Minnesota land retirement contracts in the State (as of 2013). Among all conservation easement programs, a total of 24,218 acres of agricultural land were retired throughout Renville County, and 2,718 acres were retired in the West Fork Beaver Creek Basin from 1987 through 2012. Total land retirement increased steadily from 1987 until 2000. In 2000, land retirement increased sharply because of the Minnesota River Conservation Reserve Enhancement Program, then leveled off when the program ended in 2002. Streamflow data were collected during 1999 through 2011, and total phosphorus and total suspended solids data were collected during 1999 through 2012. During this period, the highest peak streamflow of 1,320 cubic feet per second was in March 2010. Total phosphorus and total suspended solids are constituents that tend to increase with increases in streamflow. Annual flow-weighted mean total-phosphorus concentrations ranged from 0.140 to 0.759 milligrams per liter, and annual flow-weighted mean total suspended solids concentrations ranged from 21.3 to 217 milligrams per liter. Annual flow-weighted mean total phosphorus and total suspended solids concentrations decreased steadily during the first 4 years of water-quality sample collection. A downward trend in flow-weighted mean total-phosphorus concentrations was significant from 1999 through 2008; however, flow-weighted total-phosphorus concentrations increased substantially in 2009, and the total phosphorus trend was no longer significant. The high annual flow-weighted mean concentrations for total phosphorus and total suspended solids

  18. EXPERIMENTAL STUDY OF SUSPENDED INSULATORS USING OF ALUMINOUS PORCELAIN

    OpenAIRE

    Dr. S. K. Mahobia; Prof. G.R.Kumrey

    2017-01-01

    In this paper, we are studying about insulators which are used in transmission line, distribution line, power station. the best performance of the insulator during various load are achieving , the various load such as 500 Watts, 1000Watts 1500Watts, 2000Watts, 2500 watts during time. The insulator are mounted on the upper surface of pin and attached with power supply.

  19. Thermoelectric unipolar spin battery in a suspended carbon nanotube

    Science.gov (United States)

    Cao, Zhan; Fang, Tie-Feng; He, Wan-Xiu; Luo, Hong-Gang

    2017-04-01

    A quantum dot formed in a suspended carbon nanotube exposed to an external magnetic field is predicted to act as a thermoelectric unipolar spin battery which generates pure spin current. The built-in spin flip mechanism is a consequence of the spin-vibration interaction resulting from the interplay between the intrinsic spin-orbit coupling and the vibrational modes of the suspended carbon nanotube. On the other hand, utilizing thermoelectric effect, the temperature difference between the electron and the thermal bath to which the vibrational modes are coupled provides the driving force. We find that both magnitude and direction of the generated pure spin current are dependent on the strength of spin-vibration interaction, the sublevel configuration in dot, the temperatures of electron and thermal bath, and the tunneling rate between the dot and the pole. Moreover, in the linear response regime, the kinetic coefficient is non-monotonic in the temperature T and it reaches its maximum when {{k}\\text{B}}T is about one phonon energy. The existence of a strong intradot Coulomb interaction is irrelevant for our spin battery, provided that high-order cotunneling processes are suppressed.

  20. Thermoelectric unipolar spin battery in a suspended carbon nanotube.

    Science.gov (United States)

    Cao, Zhan; Fang, Tie-Feng; He, Wan-Xiu; Luo, Hong-Gang

    2017-04-26

    A quantum dot formed in a suspended carbon nanotube exposed to an external magnetic field is predicted to act as a thermoelectric unipolar spin battery which generates pure spin current. The built-in spin flip mechanism is a consequence of the spin-vibration interaction resulting from the interplay between the intrinsic spin-orbit coupling and the vibrational modes of the suspended carbon nanotube. On the other hand, utilizing thermoelectric effect, the temperature difference between the electron and the thermal bath to which the vibrational modes are coupled provides the driving force. We find that both magnitude and direction of the generated pure spin current are dependent on the strength of spin-vibration interaction, the sublevel configuration in dot, the temperatures of electron and thermal bath, and the tunneling rate between the dot and the pole. Moreover, in the linear response regime, the kinetic coefficient is non-monotonic in the temperature T and it reaches its maximum when [Formula: see text] is about one phonon energy. The existence of a strong intradot Coulomb interaction is irrelevant for our spin battery, provided that high-order cotunneling processes are suppressed.

  1. IUTAM symposium on hydrodynamic diffusion of suspended particles

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.H. [ed.

    1995-12-31

    Hydrodynamic diffusion refers to the fluctuating motion of nonBrownian particles (or droplets or bubbles) which occurs in a dispersion due to multiparticle interactions. For example, in a concentrated sheared suspension, particles do not move along streamlines but instead exhibit fluctuating motions as they tumble around each other. This leads to a net migration of particles down gradients in particle concentration and in shear rate, due to the higher frequency of encounters of a test particle with other particles on the side of the test particle which has higher concentration or shear rate. As another example, suspended particles subject to sedimentation, centrifugation, or fluidization, do not generally move relative to the fluid with a constant velocity, but instead experience diffusion-like fluctuations in velocity due to interactions with neighboring particles and the resulting variation in the microstructure or configuration of the suspended particles. In flowing granular materials, the particles interact through direct collisions or contacts (rather than through the surrounding fluid); these collisions also cause the particles to undergo fluctuating motions characteristic of diffusion processes. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  2. Suspended animation-like state protects mice from lethal hypoxia.

    Science.gov (United States)

    Blackstone, Eric; Roth, Mark B

    2007-04-01

    Joseph Priestley observed the high burn rate of candles in pure oxygen and wondered if people would "live out too fast" if we were in the same environment. We hypothesize that sulfide, a natural reducer of oxygen that is made in many cell types, acts as a buffer to prevent unrestricted oxygen consumption. To test this, we administered sulfide in the form of hydrogen sulfide (H2S) to mice (Mus musculus). As we have previously shown, H2S decreases the metabolic rate of mice by approximately 90% and induces a suspended animation-like state. Mice cannot survive for longer than 20 min when exposed to 5% oxygen. However, if mice are first put into a suspended animation-like state by a 20-min pretreatment with H2S and then are exposed to low oxygen, they can survive for more than 6.5 h in 5% oxygen with no apparent detrimental effects. In addition, if mice are exposed to a 20-min pretreatment with H2S followed by 1 h at 5% oxygen, they can then survive for several hours at oxygen tensions as low as 3%. We hypothesize that prior exposure to H2S reduces oxygen demand, therefore making it possible for the mice to survive with low oxygen supply. These results suggest that H2S may be useful to prevent damage associated with hypoxia.

  3. Skin permeation of lidocaine from crystal suspended oily formulations.

    Science.gov (United States)

    Matsui, Rakan; Hasegawa, Masaaki; Ishida, Masami; Ebata, Toshiya; Namiki, Noriyuki; Sugibayashi, Kenji

    2005-09-01

    In vitro permeation of lidocaine (lidocaine base, LID) through excised rat skin was investigated using several LID-suspended oily formulations. The first skin permeation of LID from an LID-suspended oily solution such as liquid paraffin (LP), isopropyl myristate (IPM), polyoxyethylene (2) oleylether (BO-2), and diethyl sebacate (DES) was evaluated and compared with that from polyethylene glycol 400 (PEG400) solution, a hydrophilic base. The obtained permeation rate of LID, Japp, from PEG400, LP, IPM, BO-2, and DES was in the order of DES>BO-2=IPM>LP>PEG400, and increased with LID solubility in the oily solvents, although LID crystals were dispersed in all solvents. Subsequently, oily formulations that consisted of different ratios of the first oily solvent (IPM, BO-2, or DES) (each 0-20%), the second oily solvent (LP) and an oily mixture of microcrystalline wax/white petrolatum/paraffin (1/5/4) were evaluated. BO-2 groups at a concentration of 5% and 10% had the highest Japp among the oily formulations, although a higher BO-2 resulted in lower skin permeation. In addition, pretreatment with BO-2 increased the skin permeation of LID. These results suggest that the penetration enhancing effect by the system may be related to the skin penetration of BO-2 itself. Finally, mathematical analysis was done to evaluate the effect of BO-2, and it was shown that BO-2 improved the LID solubility in stratum corneum lipids to efficiently enhance the LID permeation through skin.

  4. A Passively-Suspended Tesla Pump Left Ventricular Assist Device

    Science.gov (United States)

    Izraelev, Valentin; Weiss, William J.; Fritz, Bryan; Newswanger, Raymond K.; Paterson, Eric G.; Snyder, Alan; Medvitz, Richard B.; Cysyk, Joshua; Pae, Walter E.; Hicks, Dennis; Lukic, Branka; Rosenberg, Gerson

    2009-01-01

    The design and initial test results of a new passively suspended Tesla type LAVD blood pump are described. CFD analysis was used in the design of the pump. Overall size of the prototype device is 50 mm in diameter and 75 mm in length. The pump rotor has a density lower than that of blood and when spinning inside the stator in blood it creates a buoyant centering force that suspends the rotor in the radial direction. The axial magnetic force between the rotor and stator restrain the rotor in the axial direction. The pump is capable of pumping up to 10 liters/min at a 70 mmHg head rise at 8000 RPM. The pump has demonstrated a normalized index of hemolysis level below .02 mg/dL for flows between 2 and 9.7 L/min. An inlet pressure sensor has also been incorporated into the inlet cannula wall and will be used for control purposes. One initial in vivo study showed an encouraging result. Further CFD modeling refinements are planned as well as endurance testing of the device. PMID:19770799

  5. Assessment of CO, CO2 and Suspended Particulate Matter Emissions

    Directory of Open Access Journals (Sweden)

    Bala Isah ABDULKARIM

    2007-09-01

    Full Text Available The concentrations of carbon oxides (CO and CO2 and suspended particulate matter at Benue Cement Company (BCC and Tse-Kucha community was investigated. Results obtained, shows that concentrations of carbon dioxide of 34.40ppm, 39.50 ppm, 48.50 ppm, 78.55 ppm, 65.25 ppm, 26.80 ppm and 29.5 ppm for quarry, raw mill, cement mill, Kiln, packing house, limestone stockpile and Tse-Kucha community respectively were below the maximum standard natural concentration of CO2 in atmosphere of 600ppm while concentrations of CO (1.25ppm - 4.00ppm measured in all the sample stations were below the Nigerian Ambient Air Quality Standards (NAAQS and WHO max limit of 10 ppm - 20 ppm for an 8-hourly average time. Lastly, the concentrations of suspended particulate matter of 375 μg/m3, 338 μg/m3 and 290 μg/m3 at the cement mill, packing house and raw mill respectively were also above the World Health Organization’s (WHO’s Guidelines and Standards for Ambient Air Quality which stipulates a range of 150 μg/m3 to 230 μg/m3 for a 24- hourly average.

  6. Dependence of Some Mechanical Properties of Elastic Bands on the Length and Load Time

    Science.gov (United States)

    Triana, C. A.; Fajardo, F.

    2012-01-01

    We present a study of the maximum stress supported by elastics bands of nitrile as a function of the natural length and the load time. The maximum tension of rupture and the corresponding variation in length were found by measuring the elongation of an elastic band when a mass is suspended from its free end until it reaches the breaking point. The…

  7. Modelling of Vortex-Induced Loading on a Single-Blade Installation Setup

    DEFF Research Database (Denmark)

    Skrzypinski, Witold Robert; Gaunaa, Mac; Heinz, Joachim Christian

    2016-01-01

    Vortex-induced integral loading fluctuations on a single suspended blade at various inflow angles were modeled in the presents work by means of stochastic modelling methods. The reference time series were obtained by 3D DES CFD computations carried out on the DTU 10MW reference wind turbine blade...

  8. Distribution load estimation (DLE)

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A.; Lehtonen, M. [VTT Energy, Espoo (Finland)

    1998-08-01

    The load research has produced customer class load models to convert the customers` annual energy consumption to hourly load values. The reliability of load models applied from a nation-wide sample is limited in any specific network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to find improvements to the load models or, in general, improvements to the load estimates. In Distribution Load Estimation (DLE) the measurements from the network are utilized to improve the customer class load models. The results of DLE will be new load models that better correspond to the loading of the distribution network but are still close to the original load models obtained by load research. The principal data flow of DLE is presented

  9. Potential threat of heavy metals in re-suspended dusts on building surfaces in oilfield city

    Science.gov (United States)

    Kong, Shaofei; Lu, Bing; Bai, Zhipeng; Zhao, Xueyan; Chen, Li; Han, Bin; Li, Zhiyong; Ji, Yaqin; Xu, Yonghai; Liu, Yong; Jiang, Hua

    2011-08-01

    30 re-suspended dust samples were collected from building surfaces of an oilfield city, then re-suspended through PM 2.5, PM 10 and PM 100 inlets and analyzed for 10 metals including V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb by inductively coupled plasma-mass spectroscopy. Metals concentrations in different fractions and locations were studied. Metals sources were identified by cluster and primary component analysis. The potential risk to human health was assessed by human exposure model. Results showed that Zn, Mn, Pb and Cu were higher in all the three fractions. V, Cr, Mn and Co ranged close to the background values of Chinese soil indicating that they were mainly from crustal materials. Concentrations of Zn, Mn, Pb, V, Cr, Ni, Co and Cd were higher in old district than that in new district for the three fractions. The PM 2.5/PM 10, PM 10/PM 100 and PM 2.5/PM 100 ratios were higher for Zn, Cd, Cu, Pb, Ni, As and Cr (all higher than 1.0), and lower for Co, Mn and V (all less than or close to 1.0) which meant that anthropologic sources associated metals were more easily accumulated in finer particles than metals from crustal materials. Spatial variations indicated that the ten metals peaked at surroundings near railway station, gas stations, industrial boilers and machine manufacturing plant implying the influence of local vehicle emission, fossil fuel combustion and industrial activities as well as crustal materials which was verified by cluster analysis and primary component analysis results. Ingestion of dust particles appeared to be the main route of exposure to re-suspended dust. Hazard Indexes of As were both highest for children and adult which could be a potential threat to human health for non-cancer effect and it also exhibited the highest values for cancer effect as 1.01E-06, 7.04E-07 and 7.21E-07 for PM 2.5, PM 10 and PM 100, respectively.

  10. How Much Water and Suspended Sediment Does a Large Tropical Island Shed During a Major Hurricane? Hydrologic and Geomorphologic Effects of Hurricane Georges, September 1998, Puerto Rico

    Science.gov (United States)

    Larsen, M. C.; Webb, R. M.; Warne, A. G.

    2005-05-01

    On September 21-22 1998, Hurricane Georges, a category-3 hurricane on the Saffir-Simpson scale, produced heavy rainfall, flooding, and landslides in the mountains and coastal plains of Puerto Rico. In general, rainfall, runoff, and sediment yield vary across the 8,711 square kilometer island of Puerto Rico because of an orographic barrier, the Cordillera Central. Mean annual runoff for the island is estimated to be 910 mm (equal to 8 billion cubic meters), which is about 57 percent of mean annual precipitation: 1,600 mm (14 billion cubic meters). Mean annual suspended-sediment discharge from Puerto Rico into surrounding coastal waters is estimated at 5.9 (+/- 3.2) million metric tonnes. The largely mountainous watersheds of the island are small (tens to hundreds of square kilometers), channel gradients are steep, and most stream valleys tend to be well-incised and narrow. Major rainstorms are intense but brief. As a consequence, flood waters rise rapidly (minutes to tens of minutes) with peak discharges several orders of magnitude above base discharge, and flood waters recede quickly (hours). Major storms transport a substantial portion of suspended sediment from uplands to the coast, based on data from a set of nine suspended-sediment monitoring stations representative of typical conditions in Puerto Rico. During Hurricane Georges, U. S. Geological Survey and National Weather Service rain-gage networks recorded 2-day rainfalls that ranged from about 100 mm to 630 mm (average was 300 mm, equal to about 2.6 billion cubic meters of water). Many streams rose more than 5 meters, resulting in severe flooding in northern, southwestern, and western watersheds. Landslides dissected roads and isolated communities on both the northern and southern slopes of the Cordillera Central. More than twice the mean annual discharge flowed from some watersheds (approximately 1 billion cubic meters of water for the entire island) carrying with it one to six times the mean annual load of

  11. Removal of pesticide mixtures in a stormwater wetland collecting runoff from a vineyard catchment.

    Science.gov (United States)

    Maillard, Elodie; Payraudeau, Sylvain; Faivre, Etienne; Grégoire, Caroline; Gangloff, Sophie; Imfeld, Gwenaël

    2011-05-01

    Wetlands can collect contaminated runoff from agricultural catchments and retain dissolved and particle-laden pesticides. However, knowledge about the capacity and functioning of wetland systems with respect to the removal of pesticides is very limited. Here we show that stormwater wetlands can efficiently remove pesticides in runoff from vineyard catchments during the period of pesticide application, although flow and hydrochemical conditions of the wetland largely vary over time. During the entire agricultural season, the inflowing load of nine fungicides, six herbicides, one insecticide and four degradation products was 8.039g whereas the outflowing load was 2.181g. Removal rates of dissolved loads by the wetland ranged from 39% (simazine) to 100% (cymoxanil, gluphosinate, kresoxim methyl and terbuthylazine). Dimethomorph, diuron, glyphosate, metalaxyl and tetraconazole were more efficiently removed in spring than in summer. More than 88% of the input mass of suspended solids was retained, underscoring the capability of the wetland to trap pesticide-laden particles via sedimentation. Only the insecticide flufenoxuron was frequently detected in the wetland sediments. Our results demonstrate that stormwater wetlands can efficiently remove pesticide mixtures in agricultural runoff during critical periods of pesticide application, although fluctuations in the runoff regime and hydrochemical characteristics can affect the removal rates of individual pesticides. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Suspended Integrated Strip-line Transition Design for Highly Integrated Radar Systems

    Science.gov (United States)

    2017-03-01

    Frequency Structural Figure 3. Internal-view of SISL thru structure. Figure 2. Suspended substrate strip- line side -view. Figure 4. Top-view of trace and...response, you can see that the measured response is shifted to Figure 2. Suspended Substrate Strip- line Side -View Figure 5. Fabricated thru line ...Suspended Integrated Strip- line Transition Design for Highly Integrated Radar Systems Jay W. McDaniel, Shahrokh Saeedi, Mark B. Yeary, and

  13. Distribution load estimation - DLE

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A. [VTT Energy, Espoo (Finland)

    1996-12-31

    The load research project has produced statistical information in the form of load models to convert the figures of annual energy consumption to hourly load values. The reliability of load models is limited to a certain network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to make improvements in the load models. Distribution load estimation (DLE) is the method developed here to improve load estimates from the load models. The method is also quite cheap to apply as it utilises information that is already available in SCADA systems

  14. Hysteresis in suspended sediment to turbidity relations due to changing particle size distributions

    Science.gov (United States)

    Landers, Mark N.; Sturm, Terry W.

    2013-01-01

    Turbidity (T) is the most ubiquitous of surrogate technologies used to estimate suspended-sediment concentration (SSC). The effects of sediment size on turbidity are well documented; however, effects from changes in particle size distributions (PSD) are rarely evaluated. Hysteresis in relations of SSC-to-turbidity (SSC~T) for single stormflow events was observed and quantified for a data set of 195 concurrent measurements of SSC, turbidity, discharge, velocity, and volumetric PSD collected during five stormflows in 2009–2010 on Yellow River at Gees Mill Road in metropolitan Atlanta, Georgia. Regressions of SSC-normalized turbidity (T/SSC) on concurrently measured PSD percentiles show an inverse, exponential influence of particle size on turbidity that is not constant across the size range of the PSD. The majority of the influence of PSD on T/SSC is from particles of fine-silt and smaller sizes (finer than 16 microns). This study shows that small changes in the often assumed stability of the PSD are significant to SSC~T relations. Changes of only 5 microns in the fine silt and smaller size fractions of suspended sediment PSD can produce hysteresis in the SSC~T rating that can increase error and produce bias. Observed SSC~T hysteresis may be an indicator of changes in sediment properties during stormflows and of potential changes in sediment sources. Trends in the PSD time series indicate that sediment transport is capacity-limited for sand-sized sediment in the channel and supply-limited for fine silt and smaller sediment from the hillslope.

  15. Stormwater contaminant loading following southern California wildfires.

    Science.gov (United States)

    Stein, Eric D; Brown, Jeffrey S; Hogue, Terri S; Burke, Megan P; Kinoshita, Alicia

    2012-11-01

    Contaminant loading associated with stormwater runoff from recently burned areas is poorly understood, despite the fact that it has the potential to affect downstream water quality. The goal of the present study is to assess regional patterns of runoff and contaminant loading from wildfires in urban fringe areas of southern California. Postfire stormwater runoff was sampled from five wildfires that each burned between 115 and 658 km(2) of natural open space between 2003 and 2009. Between two and five storm events were sampled per site over the first one to two years following the fires for basic constituents, metals, nutrients, total suspended solids, and polycyclic aromatic hydrocarbons (PAHs). Results were compared to data from 16 unburned natural areas and six developed sites. Mean copper, lead, and zinc flux (kg/km(2)) were between 112- and 736-fold higher from burned catchments and total phosphorus was up to 921-fold higher compared to unburned natural areas. Polycyclic aromatic hydrocarbon flux was four times greater from burned areas than from adjacent urban areas. Ash fallout on nearby unburned watersheds also resulted in a threefold increase in metals and PAHs. Attenuation of elevated concentration and flux values appears to be driven mainly by rainfall magnitude. Contaminant loading from burned landscapes has the potential to be a substantial contribution to the total annual load to downstream areas in the first several years following fires. Copyright © 2012 SETAC.

  16. Microbial dynamics of biofilm and suspended flocs in anammox membrane bioreactor: The effect of non-woven fabric membrane.

    Science.gov (United States)

    Ren, Long-Fei; Lv, Lu; Kang, Qi; Gao, Baoyu; Ni, Shou-Qing; Chen, Yi-Han; Xu, Shiping

    2018-01-01

    Membrane bioreactor with non-woven fabric membranes (NWMBR) is developing into a suitable method for anaerobic ammonium oxidation (anammox). As a carrier, non-woven fabric membrane divided total biomass into biofilm and suspended flocs gradually. Total nitrogen removal efficiency was maintained around 82.6% under nitrogen loading rate of 567.4mgN/L/d after 260days operation. Second-order substrate removal and Stover-Kincannon models were successfully used to simulate the nitrogen removal performance in NWMBR. High-throughput sequence was employed to elucidate the underlying microbial community dynamics. Candidatus Brocadia, Kuenenia, Jettenia were detected to affirm the dominant status of anammox microorganisms and 98.2% of anammox microorganisms distributed in biofilm. In addition, abundances of functional genes (hzs, nirK) in biofilm and suspended flocs were assessed by quantitative PCR to further investigate the coexistence of anammox and other microorganisms. Potential nitrogen removal pathways were established according to relevant nitrogen removal performance and microbial community. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Storm Event Suspended Sediment-Discharge Hysteresis and Controls in Agricultural Watersheds: Implications for Watershed Scale Sediment Management.

    Science.gov (United States)

    Sherriff, Sophie C; Rowan, John S; Fenton, Owen; Jordan, Philip; Melland, Alice R; Mellander, Per-Erik; hUallacháin, Daire Ó

    2016-02-16

    Within agricultural watersheds suspended sediment-discharge hysteresis during storm events is commonly used to indicate dominant sediment sources and pathways. However, availability of high-resolution data, qualitative metrics, longevity of records, and simultaneous multiwatershed analyses has limited the efficacy of hysteresis as a sediment management tool. This two year study utilizes a quantitative hysteresis index from high-resolution suspended sediment and discharge data to assess fluctuations in sediment source location, delivery mechanisms and export efficiency in three intensively farmed watersheds during events over time. Flow-weighted event sediment export was further considered using multivariate techniques to delineate rainfall, stream hydrology, and antecedent moisture controls on sediment origins. Watersheds with low permeability (moderately- or poorly drained soils) with good surface hydrological connectivity, therefore, had contrasting hysteresis due to source location (hillslope versus channel bank). The well-drained watershed with reduced connectivity exported less sediment but, when watershed connectivity was established, the largest event sediment load of all watersheds occurred. Event sediment export was elevated in arable watersheds when low groundcover was coupled with high connectivity, whereas in the grassland watershed, export was attributed to wetter weather only. Hysteresis analysis successfully indicated contrasting seasonality, connectivity and source availability and is a useful tool to identify watershed specific sediment management practices.

  18. Occurrence and persistence of fungicides in bed sediments and suspended solids from three targeted use areas in the United States.

    Science.gov (United States)

    Smalling, Kelly L; Reilly, Timothy J; Sandstrom, Mark W; Kuivila, Kathryn M

    2013-03-01

    To document the environmental occurrence and persistence of fungicides, a robust and sensitive analytical method was used to measure 34 fungicides and an additional 57 current-use pesticides in bed sediments and suspended solids collected from areas of intense fungicide use within three geographic areas across the United States. Sampling sites were selected near or within agricultural research farms using prophylactic fungicides at rates and types typical of their geographic location. At least two fungicides were detected in 55% of the bed and 83% of the suspended solid samples and were detected in conjunction with herbicides and insecticides. Six fungicides were detected in all samples including pyraclostrobin (75%), boscalid (53%), chlorothalonil (41%) and zoxamide (22%). Pyraclostrobin, a strobilurin fungicide, used frequently in the United States on a variety of crops, was detected more frequently than p,p'-DDE, the primary degradate of p,p'-DDT, which is typically one of the most frequently occurring pesticides in sediments collected within highly agricultural areas. Maximum fungicide concentrations in bed sediments and suspended solids were 198 and 56.7 μg/kg dry weight, respectively. There is limited information on the occurrence, fate, and persistence of many fungicides in sediment and the environmental impacts are largely unknown. The results of this study indicate the importance of documenting the persistence of fungicides in the environment and the need for a better understanding of off-site transport mechanisms, particularly in areas where crops are grown that require frequent treatments to prevent fungal diseases. Published by Elsevier B.V.

  19. Final prototype of magnetically suspended flywheel energy storage system

    Science.gov (United States)

    Anand, D. K.; Kirk, J. A.; Zmood, R. B.; Pang, D.; Lashley, C.

    1991-01-01

    A prototype of a 500 Wh magnetically suspended flywheel energy storage system was designed, built, and tested. The authors present the work done and include the following: (1) a final design of the magnetic bearing, control system, and motor/generator, (2) construction of a prototype system consisting of the magnetic bearing stack, flywheel, motor, container, and display module, and (3) experimental results for the magnetic bearings, motor, and the entire system. The successful completion of the prototype system has achieved: (1) manufacture of tight tolerance bearings, (2) stability and spin above the first critical frequency, (3) use of inside sensors to eliminate runout problems, and (4) integration of the motor and magnetic bearings.

  20. Thermal Conductivity Measurement of Liquids by Using a Suspended Microheater

    Science.gov (United States)

    Oh, Dong-Wook

    2017-10-01

    In this paper, the traditional 3ω method is modified in order to measure the thermal conductivity of a droplet of liquid. The 3ω sensor is microfabricated using bulk silicon etching on a silicon wafer to form a microheater on a suspended bridge structure. The Si substrate of over 400 μ m thickness beneath the microheater is etched away so that the sample liquid can fill the gap created between the heater and the bottom boundary of the sensor. The frequency of the sinusoidal heating pulses that are generated from the heater is controlled such that the thermal penetration depth is much smaller than the thickness of the liquid layer. The temperature oscillation of the sample fluid is measured at the thin-film heater to calculate the thermal conductivity of the surrounding fluid. The thermal conductivity and measured values of the de-ionized water and ethanol show a good agreement with the theoretical values at room temperature.

  1. Suspended sediment in a high-Arctic river

    DEFF Research Database (Denmark)

    Ladegaard-Pedersen, Pernille; Sigsgaard, Charlotte; Kroon, Aart

    2017-01-01

    Quantifying fluxes of water, sediment and dissolved compounds through Arctic rivers is important for linking the glacial, terrestrial and marine ecosystems and to quantify the impact of a warming climate. The quantification of fluxes is not trivial. This study uses a 8-years data set (2005......-2012) of daily measurements from the high-Artic Zackenberg River in Northeast Greenland to estimate annual suspended sediment fluxes based on four commonly used methods: M1) is the discharge weighted mean and uses direct measurements, while M2-M4) are one uncorrected and two bias corrected rating curves......-daily sampling together with a sampling frequency of 2h during extreme events. The most consistent estimation method was an uncorrected rating curve of bi-daily measurements (M2), combined with a linear interpolation of extreme event fluxes. Sampling can be reduced to every fourth day, with both method...

  2. Fluorine and sulfur simultaneously co-doped suspended graphene

    Science.gov (United States)

    Struzzi, C.; Sezen, H.; Amati, M.; Gregoratti, L.; Reckinger, N.; Colomer, J.-F.; Snyders, R.; Bittencourt, C.; Scardamaglia, M.

    2017-11-01

    Suspended graphene flakes are exposed simultaneously to fluorine and sulfur ions produced by the μ-wave plasma discharge of the SF6 precursor gas. The microscopic and spectroscopic analyses, performed by Raman spectroscopy, scanning electron microscopy and photoelectron spectromicroscopy, show the homogeneity in functionalization yield over the graphene flakes with F and S atoms covalently bonded to the carbon lattice. This promising surface shows potential for several applications ranging from biomolecule immobilization to lithium battery and hydrogen storage devices. The present co-doping process is an optimal strategy to engineer the graphene surface with a concurrent hydrophobic character, thanks to the fluorine atoms, and a high affinity with metal nanoparticles due to the presence of sulfur atoms.

  3. Heat Transfer Correlations for Free Convection from Suspended Microheaters

    Directory of Open Access Journals (Sweden)

    David GOSSELIN

    2016-08-01

    Full Text Available Portability and autonomy for biomedical diagnostic devices are two rising requirements. It is recognized that low-energy heating of such portable devices is of utmost importance for molecular recognition. This work focuses on screen-printed microheaters based on on Joule effect, which constitute an interesting solution for low-energy heating. An experimental study of the natural convection phenomena occurring with such microheaters is conducted. When they are suspended in the air, and because of the thinness of the supporting film, it is shown that the contributions of both the upward and downward faces have to be taken into account. A total Nusselt number and a total convective heat transfer coefficient have been used to describe the natural convection around these microheaters. In addition a relation between the Nusselt number and the Rayleigh number is derived, leading to an accurate prediction of the heating temperature (MRE< 2 %.

  4. Giant magneto-photoelectric effect in suspended graphene

    Science.gov (United States)

    Sonntag, Jens; Kurzmann, Annika; Geller, Martin; Queisser, Friedemann; Lorke, Axel; Schützhold, Ralf

    2017-06-01

    We study the optical response of a suspended, monolayer graphene field-effect transistor structure in magnetic fields of up to 9 T (quantum Hall regime). With an illumination power of only 3 μW, we measure a photocurrent of up to 400 nA (without an applied bias) corresponding to a photo-responsivity of 0.13 A W-1, which we believe to be one of the highest values ever measured in single-layer graphene. We discuss possible mechanisms for generating this strong photo-response (17 electron-hole pairs per 100 incident photons). Based on our experimental findings, we believe that the most likely scenario is a ballistic two-stage process including carrier multiplication via Auger-type inelastic Coulomb scattering at the graphene edge.

  5. Net transport of suspended matter due to tidal straining

    Science.gov (United States)

    Jones, S. E.; Jago, C. F.; Simpson, J. H.; Rippeth, T. P.

    2003-04-01

    Net transport of suspended particulate matter (SPM) is well-known in tidal regions where there is time-velocity asymmetry due to frictional modification of the tide in shallow water. We present here observations which show a new mechanism for net flux of SPM in response to tidal straining in a region of freshwater influence (ROFI). In situ measurements of the particle size of suspended particulate matter (SPM) and turbulent energy dissipation have been made at a site in Liverpool Bay (Irish Sea) where there is significant resuspension of particles from the muddy sand substrate during spring tides. This is a ROFI where tidal straining dominates the temporal development of turbulence. On a spring tide the water column tries to stratify on the ebb and destratify on the flood, but these tendencies are masked by mixing due to tidal stirring. Nevertheless, there is a marked excess of TKE dissipation rate E on the flood, especially in the upper part of the water column. Resuspension occurs on both flood and ebb, but SPM flux is strongly asymmetric with a net shorewards component. Asymmetry is most pronounced for the larger particles which comprise most of the mass. Enhanced ? on the flood mixes large particles upwards into faster flowing water, which increases the flux. Comparable upwards mixing of large particles does not occur on the ebb where enhanced E is confined to slower bottom waters. The net flux is not seen on neap tides because, although there is more stratification due to tidal straining, there is essentially no resuspension. The net flux on springs is undoubtedly an important component of SPM transport (and any comparable particulates) in coastal regions.

  6. A multi-material topology optimization approach for wrinkle-free design of cable-suspended membrane structures

    Science.gov (United States)

    Luo, Yangjun; Niu, Yanzhuang; Li, Ming; Kang, Zhan

    2017-06-01

    In order to eliminate stress-related wrinkles in cable-suspended membrane structures and to provide simple and reliable deployment, this study presents a multi-material topology optimization model and an effective solution procedure for generating optimal connected layouts for membranes and cables. On the basis of the principal stress criterion of membrane wrinkling behavior and the density-based interpolation of multi-phase materials, the optimization objective is to maximize the total structural stiffness while satisfying principal stress constraints and specified material volume requirements. By adopting the cosine-type relaxation scheme to avoid the stress singularity phenomenon, the optimization model is successfully solved through a standard gradient-based algorithm. Four-corner tensioned membrane structures with different loading cases were investigated to demonstrate the effectiveness of the proposed method in automatically finding the optimal design composed of curved boundary cables and wrinkle-free membranes.

  7. Seasonal variation of polychlorinated biphenyl congeners in surficial sediment, trapped settling material, and suspended particulate material in Lake Michigan, USA.

    Science.gov (United States)

    Robinson, Sander D; Landrum, Peter F; Van Hoof, Patricia L; Eadie, Brian J

    2008-02-01

    A unique time series of surface sediment, trapped settling material, and suspended particulate material polychlorinated biphenyl (PCB) samples were collected at a 45-m deep site off Grand Haven (MI, USA) over a 14-month period. Both concentrations and congener distributions remained constant for the sediments, although there were seasonal and interannual variability in the other matrices. Trapped settling material and suspended particulate material PCB concentrations were substantially lower (~50%) in 1997 than in the samples from December 1997 through July 1998. The cause could not be determined from the data collected, but there were some very large storms during the winter-spring period of 1998, resulting in major sediment resuspension throughout the southern basin. Observed seasonal variation in PCB concentration and congener distribution on particles likely was due to the changes in particle composition. These include particle size and the source of particles (such as the amount of resuspended sediment in trapped settling material), and the role of diagenesis of the organic matter on particles.

  8. Relations between continuous real-time turbidity data and discrete suspended-sediment concentration samples in the Neosho and Cottonwood Rivers, east-central Kansas, 2009-2012

    Science.gov (United States)

    Foster, Guy M.

    2014-01-01

    The Neosho River and its primary tributary, the Cottonwood River, are the primary sources of inflow to the John Redmond Reservoir in east-central Kansas. Sedimentation rate in the John Redmond Reservoir was estimated as 743 acre-feet per year for 1964–2006. This estimated sedimentation rate is more than 80 percent larger than the projected design sedimentation rate of 404 acre-feet per year, and resulted in a loss of 40 percent of the conservation pool since its construction in 1964. To reduce sediment input into the reservoir, the Kansas Water Office implemented stream bank stabilization techniques along an 8.3 mile reach of the Neosho River during 2010 through 2011. The U.S. Geological Survey, in cooperation with the Kansas Water Office and funded in part through the Kansas State Water Plan Fund, operated continuous real-time water-quality monitors upstream and downstream from stream bank stabilization efforts before, during, and after construction. Continuously measured water-quality properties include streamflow, specific conductance, water temperature, and turbidity. Discrete sediment samples were collected from June 2009 through September 2012 and analyzed for suspended-sediment concentration (SSC), percentage of sediments less than 63 micrometers (sand-fine break), and loss of material on ignition (analogous to amount of organic matter). Regression models were developed to establish relations between discretely measured SSC samples, and turbidity or streamflow to estimate continuously SSC. Continuous water-quality monitors represented between 96 and 99 percent of the cross-sectional variability for turbidity, and had slopes between 0.91 and 0.98. Because consistent bias was not observed, values from continuous water-quality monitors were considered representative of stream conditions. On average, turbidity-based SSC models explained 96 percent of the variance in SSC. Streamflow-based regressions explained 53 to 60 percent of the variance. Mean squared

  9. 76 FR 6462 - Notice of Intent To Suspend Certain Pesticide Registrations

    Science.gov (United States)

    2011-02-04

    ... hearing is made by a person adversely affected by the Notice of Intent to Suspend or the registrant has... this notice (i.e., how to request a hearing or how to comply fully with the requirements that served as... name notice of intent No. to suspend The Fountainhead Group, Inc.... Resmethrin 53853-1 Burgess Insect...

  10. 19 CFR 351.222 - Revocation of orders; termination of suspended investigations.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Revocation of orders; termination of suspended investigations. 351.222 Section 351.222 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE... orders; termination of suspended investigations. (a) Introduction. “Revocation” is a term of art that...

  11. Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data

    NARCIS (Netherlands)

    Shen, F.; Verhoef, W.; Zhou, Y.; Salama, M.S.; Liu, X.

    2010-01-01

    The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of

  12. 75 FR 60720 - Antidumping or Countervailing Duty Order, Finding, or Suspended Investigation; Advance...

    Science.gov (United States)

    2010-10-01

    ... Goldberger, (202) 482-4136. from South Korea (A-580-836) (2rd Review). Granular Polytetrafluoroethylene Resin... South Korea (C-580-837) (2rd Review). Suspended Investigations No Sunset Review of suspended...; Advance Notification of Sunset Reviews AGENCY: Import Administration, International Trade Administration...

  13. Mechanical properties of freely suspended semiconducting graphene-like layers based on MoS2

    NARCIS (Netherlands)

    Castellanos-Gomez, A.; Poot, M.; Steele, G.A.; Van der Zant, H.S.J.; Agrait, N.; Rubio-Bollinger, G.

    2012-01-01

    We fabricate freely suspended nanosheets of molybdenum disulphide (MoS2) which are characterized by quantitative optical microscopy and high-resolution friction force microscopy. We study the elastic deformation of freely suspended nanosheets of MoS2 using an atomic force microscope. The Young’s

  14. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Science.gov (United States)

    2010-07-01

    ... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Liquid, suspended particulate, and solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION...

  15. Cricket inspired sensory hairs on suspended membranes with capacitive displacement detection

    NARCIS (Netherlands)

    van Baar, J.J.J.; Dijkstra, Marcel; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.

    2004-01-01

    This paper presents the fabrication of artificial hairs of siliconnitride and SU-8 on suspended membranes for flow sensing applications. The suspended membranes contain electrodes for capacitive sensing of the rotation of the hairs. For the siliconnitride hairs a silicon wafer is used as mould and

  16. High suspended solids as a factor in reproductive failure of a freshwater mussel

    Science.gov (United States)

    Andrew M. Gascho-Landis; Wendell R. Haag; James A. Stoeckel

    2013-01-01

    Elevated suspended solids are a widespread stressor of aquatic ecosystems, but their effects on growth and reproduction in freshwater mussels are largely unknown. We fertilized experimental ponds to create a gradient in total suspended solids (TSS) and examined the effects of TSS on growth, nutritional status, reproduction, and clearance rate in Ligumia subrostrata....

  17. Physical and biological changes of suspended particles in a free surface flow constructed wetland

    NARCIS (Netherlands)

    Mulling, B.T.M.; van den Boomen, R.M.; Claassen, T.H.L.; van der Geest, H.G.; Kappelhof, J.W.N.M.; Admiraal, W.

    2013-01-01

    Suspended particles are considered as contaminants in treated wastewater and can have profound effects on the biological, physical and chemical properties of receiving aquatic ecosystems, depending on the concentration, type and nature of the suspended particles. Constructed wetlands are known to

  18. BCG-loaded chitosan microparticles: interaction with macrophages and preliminary in vivo studies.

    Science.gov (United States)

    Caetano, Liliana Aranha; Figueiredo, Lara; Almeida, António J; Gonçalves, L M D

    2017-03-01

    The aim of this study was to develop a novel BCG-loaded chitosan vaccine with high association efficiency which can afford efficient interaction with APC and elicit local and Th1-type-specific immune response after intranasal administration. Chitosan-suspended BCG and BCG-loaded chitosan-alginate microparticles were prepared by ionotropic gelation. Interaction with APC was evaluated by fluorescence microscopy using rBCG-GFP. Specific immune responses were evaluated following intranasal immunisation of mice. Cellular uptake was approximately two-fold higher for chitosan-suspended BCG. A single dose of BCG-loaded microparticles or chitosan-suspended BCG by intranasal route improved Th1-type response compared with subcutaneous BCG. Chitosan-suspended BCG originated the highest mucosal response in the lungs by intranasal route. These positive results indicate that the proposed approach of whole live BCG microencapsulation in chitosan-alginate for intranasal immunisation was successful in allowing efficient interaction with APC, while improving the cellular immune response, which is of interest for local immunisation against tuberculosis.

  19. Quantitative suspended sediment mapping using aircraft remotely sensed multispectral data. [in Virginia

    Science.gov (United States)

    Johnson, R. W.

    1975-01-01

    Suspended sediment is an important environmental parameter for monitoring water quality, water movement, and land use. Quantitative suspended sediment determinations were made from analysis of aircraft remotely sensed multispectral digital data. A statistical analysis and derived regression equation were used to determine and plot quantitative suspended sediment concentration contours in the tidal James River, Virginia, on May 28, 1974. From the analysis, a single band, Band 8 (0.70-0.74 microns), was adequate for determining suspended sediment concentrations. A correlation coefficient of 0.89 was obtained with a mean inaccuracy of 23.5 percent for suspended sediment concentrations up to about 50 mg/l. Other water quality parameters - secchi disc depth and chlorophyll - also had high correlations with the remotely sensed data. Particle size distribution had only a fair correlation with the remotely sensed data.

  20. Quantification of suspended sediment transfers in a lowland agricultural catchment

    Science.gov (United States)

    Salvador-Blanes, Sebastien; Manière, Louis; Grangeon, Thomas; Cerdan, Olivier; Evrard, Olivier; Foucher, Anthony; Vandromme, Rosalie

    2017-04-01

    Lowland agricultural landscapes underwent important changes since the second half of the XXth century such as hedges removal, implementation of drainage systems, stream redesign and land reallocation. It resulted in changes in sediment transfer processes, and in widespread morphological alterations of water bodies. However, little is known about the sediment dynamics in these environments. The Louroux catchment (25 km2) is located in central France. It is a typical intensively cultivated and tile drained lowland catchment. The Xth century pond located at its outlet (52 ha) is undergoing large siltation, with a current sedimentation rate 60 fold higher than the pre-1950 period. Five monitoring stations, measuring water levels and turbidity at high frequency (15 mn and 1 mn respectively), combined with automatic samplers, were implemented in 2013. Three stations are located at the main tributaries outlets of the pond, one in a sub-catchment, and one at a tile drain outlet. 45 floods were observed during the three studied hydrological years. They occurred mostly between December and March (33 floods) and in May-June (8 floods). Specific sediment yields ranged from 0.02 to 0.38 t.ha-1.yr-1 depending on the monitoring site and the considered year. The vast majority of suspended sediment transfers occur during the winter floods. While large water volumes were also measured during spring floods, the sediment yields remained low. Suspended sediment yields present large inter-annual (ratio ranging between 2 and 6 depending on the monitoring station) and spatial variations, due to significant differences in total rainfall amounts during the winter season and variations in land use, respectively. The processes related to sediment transfers are most likely linked to soil saturation during winter despite the presence of a tile drainage network, with transfers occurring both at the soil surface and through the drainage system. While sediment transfer rates can be considered as

  1. Suspended sediment yield and metal contamination in a river catchment affected by El Niño events and gold mining activities: the Puyango river basin, southern Ecuador

    Science.gov (United States)

    Tarras-Wahlberg, N. H.; Lane, S. N.

    2003-10-01

    The suspended sediment yield and the transfer of polluted sediment are investigated for the Puyango river basin in southern Ecuador. This river system receives metal (Cd, Cu, Hg, Pb and Zn) and cyanide pollution generated by mining, and is associated with large-scale hydrological variability, which is partly governed by El Niño events. Field sampling and statistical modelling methods are used to quantify the amount of mine tailings that is discharged into the basin. Annual suspended sediment yields are estimated using a novel combination of the suspended sediment rating method and Monte Carlo simulations, which allow for propagation of the uncertainties of the calculations that lead to final load estimates. Geochemical analysis of suspended and river bed sediment is used to assess the dispersion and long-term fate of contaminated sediment within the river catchment. Knowledge of the inter- and intra-annual variation in suspended sediment yield is shown to be crucial for judging the importance of mining discharges, and the extent to which the resultant pollution is diluted by river flows. In wet years, polluted sediments represent only a very small proportion of the yield estimates, but in dry years the proportion can be significant. Evidence shows that metal contaminated sediments are stored in the Puyango river bed during low flows. Large flood events flush this sediment periodically, both on an annual cycle associated with the rainy season, and also related to El Niño events. Therefore, environmental impacts of mining-related discharges are more likely to be severe during dry years compared with wet years, and in the dry season rather than the wet season. The hydrological consequences of El Niño events are shown to depend upon the extent to which these events penetrate inland. It is, thus, shown that the general conclusion that El Niño events can significantly affect suspended sediment yields needs evaluation with respect to the particular way in which those

  2. Improved estimates of filtered total mercury loadings and total mercury concentrations of solids from potential sources to Sinclair Inlet, Kitsap County, Washington

    Science.gov (United States)

    Paulson, Anthony J.; Conn, Kathleen E.; DeWild, John F.

    2013-01-01

    Previous investigations examined sources and sinks of mercury to Sinclair Inlet based on historic and new data. This included an evaluation of mercury concentrations from various sources and mercury loadings from industrial discharges and groundwater flowing from the Bremerton naval complex to Sinclair Inlet. This report provides new data from four potential sources of mercury to Sinclair Inlet: (1) filtered and particulate total mercury concentrations of creek water during the wet season, (2) filtered and particulate total mercury releases from the Navy steam plant following changes in the water softening process and discharge operations, (3) release of mercury from soils to groundwater in two landfill areas at the Bremerton naval complex, and (4) total mercury concentrations of solids in dry dock sumps that were not affected by bias from sequential sampling. The previous estimate of the loading of filtered total mercury from Sinclair Inlet creeks was based solely on dry season samples. Concentrations of filtered total mercury in creek samples collected during wet weather were significantly higher than dry weather concentrations, which increased the estimated loading of filtered total mercury from creek basins from 27.1 to 78.1 grams per year. Changes in the concentrations and loading of filtered and particulate total mercury in the effluent of the steam plant were investigated after the water softening process was changed from ion-exchange to reverse osmosis and the discharge of stack blow-down wash began to be diverted to the municipal water-treatment plant. These changes reduced the concentrations of filtered and particulate total mercury from the steam plant of the Bremerton naval complex, which resulted in reduced loadings of filtered total mercury from 5.9 to 0.15 grams per year. Previous investigations identified three fill areas on the Bremerton naval complex, of which the western fill area is thought to be the largest source of mercury on the base

  3. Probabilistic model of bridge vehicle loads in port area based on in-situ load testing

    Science.gov (United States)

    Deng, Ming; Wang, Lei; Zhang, Jianren; Wang, Rei; Yan, Yanhong

    2017-11-01

    Vehicle load is an important factor affecting the safety and usability of bridges. An statistical analysis is carried out in this paper to investigate the vehicle load data of Tianjin Haibin highway in Tianjin port of China, which are collected by the Weigh-in- Motion (WIM) system. Following this, the effect of the vehicle load on test bridge is calculated, and then compared with the calculation result according to HL-93(AASHTO LRFD). Results show that the overall vehicle load follows a distribution with a weighted sum of four normal distributions. The maximum vehicle load during the design reference period follows a type I extremum distribution. The vehicle load effect also follows a weighted sum of four normal distributions, and the standard value of the vehicle load is recommended as 1.8 times that of the calculated value according to HL-93.

  4. Measurements of Plutonium and Americium in Soil Samples from Project 57 using the Suspended Soil Particle Sizing System (SSPSS)

    Energy Technology Data Exchange (ETDEWEB)

    John L. Bowen; Rowena Gonzalez; David S. Shafer

    2001-05-01

    As part of the preliminary site characterization conducted for Project 57, soils samples were collected for separation into several size-fractions using the Suspended Soil Particle Sizing System (SSPSS). Soil samples were collected specifically for separation by the SSPSS at three general locations in the deposited Project 57 plume, the projected radioactivity of which ranged from 100 to 600 pCi/g. The primary purpose in focusing on samples with this level of activity is that it would represent anticipated residual soil contamination levels at the site after corrective actions are completed. Consequently, the results of the SSPSS analysis can contribute to dose calculation and corrective action-level determinations for future land-use scenarios at the site.

  5. Proposal of law which aims at limiting the energy loads in collective buildings for accommodation purpose; Proposition de loi visant a limiter les charges energetiques dans les immeubles collectifs a usage d'habitation

    Energy Technology Data Exchange (ETDEWEB)

    Cochet, Y.; Billard, M.; Mamere, N.

    2002-07-01

    The aim of this proposal of law is to limit to 40% maximum the share of electricity in the production of heat and hot water in new collective residential buildings. Electric heating is the less expensive solution in terms of investment but certainly the most expensive solution on the long term use for the budget of households. (J.S.)

  6. Spatial and Temporal Dynamics of Fecal Coliform and Associated with Suspended Solids and Water within Five Northern California Estuaries.

    Science.gov (United States)

    Lewis, David J; Atwill, Edward R; Pereira, Maria das Graças C; Bond, Ronald

    2013-01-01

    Fecal coliform and associated with suspended solids (SS) and water in five northern California estuaries were studied to document process influences and water quality monitoring biases affecting indicator bacteria concentrations. We collected and analyzed 2371 samples during 10 sampling events for the five studied estuaries. Concentrations during wet-season stormflow conditions were greater than during wet-season base flow and dry-season base flow conditions. Results also document concentration gradients across the length of the studied estuaries and with depth of sample collection. Highest concentrations were associated with shallow samples collected furthest inland. Corresponding decreases occurred the deeper and closer to the estuary mouth a sample was collected. Results also identify direct relationships of wind speed and discharge velocity and indirect relationship of tide stage to indicator bacteria concentrations. Bacteria associated with suspended solids (SS), after conversion to the same units of measurement (mass), were three orders of magnitude greater than in the water fraction. However, the mean proportion contributed by SS to composite water sample concentrations was 8% (SE 0.3) for fecal coliform and 7% (SE 0.3) for . Bacteria from the SS proportion is related to seasonality, tide stage, and discharge velocity that are consistent with mechanisms for entrainment, transport of SS, and reduced particle settling. These results are important for both managing and monitoring these systems by improving sample spatial and temporal context and corresponding bacteria concentration values across the freshwater-saltwater interface. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  7. Salinity and suspended matter variations in the Tay estuary

    Science.gov (United States)

    McManus, John

    2005-03-01

    The concept of salinity-induced density layering in estuaries was first demonstrated from the upper reaches of the Tay. In this study the nature of the layering and its variation through the tidal cycle is demonstrated from time series of observations taken at many locations within this estuary. Thorough mixing of the waters on the rising tide, as defined by depth profiles of salinity, is commonly replaced by salinity layering during the high water slack period. This condition continues into the falling tide. Frequently the mixed waters are abruptly replaced by stratified waters within the half-hourly sampling interval. This is attributed to the activity of longitudinal fronts, manifest as surficial foam bands, along which water masses shear past each other on both the flood and ebb tides. Offsetting of transverse salinity coutours along the fronts is introduced to explain apparent complexities in surface water salinity distributions measured at high water slack. Suspended particulate matter concentrations increase towards the limit of the saline water intrusion before decreasing headwards into the freshwater zone of the estuary. The suspensions in the water column may also be displaced by the lateral offsetting of the waters along the fronts. The recognition of the presence of fronts, and a knowledge of their impact on the estuarine waters may provide an alternative means of understanding the flow characteristics of these challenging water bodies. The techniques of spatial and temporal averaging normally widely used today may not be the most realistic approach to analysis of the flows.

  8. Surface tension of Nanofluid-type fuels containing suspended nanomaterials.

    Science.gov (United States)

    Tanvir, Saad; Qiao, Li

    2012-04-18

    The surface tension of ethanol and n-decane based nanofluid fuels containing suspended aluminum (Al), aluminum oxide (Al2O3), and boron (B) nanoparticles as well as dispersible multi-wall carbon nanotubes (MWCNTs) were measured using the pendant drop method by solving the Young-Laplace equation. The effects of nanoparticle concentration, size and the presence of a dispersing agent (surfactant) on surface tension were determined. The results show that surface tension increases both with particle concentration (above a critical concentration) and particle size for all cases. This is because the Van der Waals force between particles at the liquid/gas interface increases surface free energy and thus increases surface tension. At low particle concentrations, however, addition of particles has little influence on surface tension because of the large distance between particles. An exception is when a surfactant was used or when (MWCNTs) was involved. For such cases, the surface tension decreases compared to the pure base fluid. The hypothesis is the polymer groups attached to (MWCNTs) and the surfactant layer between a particle and the surround fluid increases the electrostatic force between particles and thus reduce surface energy and surface tension.

  9. Surface tension of Nanofluid-type fuels containing suspended nanomaterials

    Science.gov (United States)

    2012-01-01

    The surface tension of ethanol and n-decane based nanofluid fuels containing suspended aluminum (Al), aluminum oxide (Al2O3), and boron (B) nanoparticles as well as dispersible multi-wall carbon nanotubes (MWCNTs) were measured using the pendant drop method by solving the Young-Laplace equation. The effects of nanoparticle concentration, size and the presence of a dispersing agent (surfactant) on surface tension were determined. The results show that surface tension increases both with particle concentration (above a critical concentration) and particle size for all cases. This is because the Van der Waals force between particles at the liquid/gas interface increases surface free energy and thus increases surface tension. At low particle concentrations, however, addition of particles has little influence on surface tension because of the large distance between particles. An exception is when a surfactant was used or when (MWCNTs) was involved. For such cases, the surface tension decreases compared to the pure base fluid. The hypothesis is the polymer groups attached to (MWCNTs) and the surfactant layer between a particle and the surround fluid increases the electrostatic force between particles and thus reduce surface energy and surface tension. PMID:22513039

  10. High-field electrical and thermal transport in suspended graphene.

    Science.gov (United States)

    Dorgan, Vincent E; Behnam, Ashkan; Conley, Hiram J; Bolotin, Kirill I; Pop, Eric

    2013-10-09

    We study the intrinsic transport properties of suspended graphene devices at high fields (≥1 V/μm) and high temperatures (≥1000 K). Across 15 samples, we find peak (average) saturation velocity of 3.6 × 10(7) cm/s (1.7 × 10(7) cm/s) and peak (average) thermal conductivity of 530 W m(-1) K(-1) (310 W m(-1) K(-1)) at 1000 K. The saturation velocity is 2-4 times and the thermal conductivity 10-17 times greater than in silicon at such elevated temperatures. However, the thermal conductivity shows a steeper decrease at high temperature than in graphite, consistent with stronger effects of second-order three-phonon scattering. Our analysis of sample-to-sample variation suggests the behavior of "cleaner" devices most closely approaches the intrinsic high-field properties of graphene. This study reveals key features of charge and heat flow in graphene up to device breakdown at ~2230 K in vacuum, highlighting remaining unknowns under extreme operating conditions.

  11. Deterministic separation of suspended particles in a reconfigurable obstacle array

    CERN Document Server

    Du, Siqi

    2015-01-01

    We use a macromodel of a flow-driven deterministic lateral displacement (DLD) microfluidic system to investigate conditions leading to size-separation of suspended particles. This model system can be easily reconfigured to establish an arbitrary orientation between the average flow field and the array of obstacles comprising the stationary phase (forcing angle). We also investigate the effect of obstacle size using two arrays with different obstacles but same surface-to-surface distance between them. In all cases, we observe the presence of a locked mode at small forcing angles, in which particles move along a principal direction in the lattice until a locked-to-zigzag transition takes place when the driving force reaches a critical angle. We show that the transition occurs at increasing angles for larger particles, thus enabling particle separation at specific forcing angles. Moreover, we observe a linear correlation between the critical angle and the size of the particles that could be used in the design of...

  12. Remote Sensing of Suspended Sediment Over Gulf of Martaban

    Directory of Open Access Journals (Sweden)

    Matamin Abd Rahman

    2015-03-01

    Full Text Available Gulf of Martaban is located at the north of Andaman, and is one of the world most turbid areas. The presence of suspended sediment concentration (SSC in the water body could reduce the underwater transmittance. This study has been conducted to investigate the variation of SSC over the Gulf of Martaban. Remote sensing reflectance (Rrs of 667 nm is used as a proxy to represent the sediment SSC variation over the study area. The data for the period of July 2002 to March 2014 acquired from MODIS Aqua 4 km resolution are used in this study. As a result, there is no obvious yearly variation in the SSC cover area. The SSC variation over this study area is found to be seasonal. High homogenous SSC covers area observably during the northeast (NE monsoon season that occurs from December to January. The sediment cover area could reach the latitude of 15°N that located at the south of the gulf. During southwest (SW monsoon season that occurs from May to September, low and sparse SSC cover area is observed. As a consequence, the area covered by the SSC is higher during the NE monsoon season as compared to the SW monsoon season. Hence, the SSC cover area during the NE monsoon season is greater than the yearly averaged SSC cover area. Meanwhile the SSC cover area during the rainy SW monsoon season is less than the yearly and NE monsoon season.

  13. Ensemble Modeling of Suspended Sediment in Steep Mountain Catchments

    Science.gov (United States)

    Stewart, J.; Raseman, W. J.; Kasprzyk, J. R.; Livneh, B.

    2016-12-01

    Climatic and land cover changes present important uncertainties into the rates of soil erosion and sedimentation in watersheds. Soil erosion adds constituents to streams, altering water chemistry and streambed morphology, which can adversely affect aquatic life and poses a critical challenge for water treatment and reservoir management. The goal of this research is to establish estimates of sediment transport within large-scale mountainous catchments (>1000 km2). As sedimentation rates are impacted by numerous physical processes including soil, land cover, slope and climate; the results from seven models will be presented to quantify uncertainty and improve predictability. A broader inquiry made here is into the efficacy of model structure under different conditions. We present the results from empirical, stochastic, conceptual and physical models. These include empirical models: monovariate rating curve, multivariate regression and the Modified Universal Soil Loss Equation (MUSLE), to models with conceptual components: Soil Water Assessment Tool (SWAT) to more physically based models: Water Erosion Prediction Project (WEPP), Precipitation Runoff Modeling System (PRMS) and Distributed Hydrology Soil Vegetation Model (DHSVM). Key uncertainties will be characterized resulting from forcing inputs, parameter selection, scale discretization, and model structure. Calibration results from a multi-objective optimization routine will be presented that optimize parameters and identify performance trade-offs that will be used to develop uncertainty estimates in both streamflow and sediment projections. The outcomes of this research will highlight critical issues relevant to large-scale hydrologic and suspended sediment prediction initiatives.

  14. Event-based total suspended sediment particle size distribution model

    Science.gov (United States)

    Thompson, Jennifer; Sattar, Ahmed M. A.; Gharabaghi, Bahram; Warner, Richard C.

    2016-05-01

    One of the most challenging modelling tasks in hydrology is prediction of the total suspended sediment particle size distribution (TSS-PSD) in stormwater runoff generated from exposed soil surfaces at active construction sites and surface mining operations. The main objective of this study is to employ gene expression programming (GEP) and artificial neural networks (ANN) to develop a new model with the ability to more accurately predict the TSS-PSD by taking advantage of both event-specific and site-specific factors in the model. To compile the data for this study, laboratory scale experiments using rainfall simulators were conducted on fourteen different soils to obtain TSS-PSD. This data is supplemented with field data from three construction sites in Ontario over a period of two years to capture the effect of transport and deposition within the site. The combined data sets provide a wide range of key overlooked site-specific and storm event-specific factors. Both parent soil and TSS-PSD in runoff are quantified by fitting each to a lognormal distribution. Compared to existing regression models, the developed model more accurately predicted the TSS-PSD using a more comprehensive list of key model input parameters. Employment of the new model will increase the efficiency of deployment of required best management practices, designed based on TSS-PSD, to minimize potential adverse effects of construction site runoff on aquatic life in the receiving watercourses.

  15. Design of Experimental Suspended Footbridge with Deck Made of UHPC

    Directory of Open Access Journals (Sweden)

    Blank Marek

    2016-01-01

    Full Text Available This paper deals with the static and dynamic design of experimental footbridge for pedestrians and cyclists in the municipality Lužec nad Vltavou in Czech Republic, Europe. This work aims to familiarize the reader with calculations carried out and the results obtained, describing the static and dynamic properties of proposed footbridge. The construction of footbridge is designed as a suspended structure with prestressed bridge deck consisting of prefabricated UHPC panels and reversed “V” shaped steel pylon with height of approximately 40 meters. The deck is anchored using 24 steel hangers in one row in a steel pylon - 17 ropes in the main span and 7 cables on the other side. Range of the main span is 99.18 meters and the secondary span is 31.9 m. Deck width is 4.5 meters with 3.0 meters passing space. The bridge is designed for the possibility of passage of vehicles weighting up to 3.5 tons. Deck panels are made of UHPC with reinforcement. At the edge of the bridge on the side of the shorter span the bridge deck is firmly connected with abutment and on the other deck it is stored using a pair of sliding bearings. The utilization of the excellent properties of UHPC allows to design a very thin and lightweight construction of the deck, which could not be achieved with the use of normal concrete.

  16. Suspended sediment dynamics in the Amazon River of Peru

    Science.gov (United States)

    Armijos, Elisa; Crave, Alain; Vauchel, Philippe; Fraizy, Pascal; Santini, William; Moquet, Jean-Sèbastien; Arevalo, Nore; Carranza, Jorge; Guyot, Jean-Loup

    2013-07-01

    The erosion and transport of sediments allow us to understand many activities of significance, such as crust evolution, climate change, uplift rates, continental processes, the biogeochemical cycling of pollutants and nutrients. The Amazon basin of Peru has contrasting physiographic and climatic characteristics between the Andean piedmont and the plains and between the north and south of the basin which is why there are 8 gauging stations located along the principal rivers of the Andean piedmont (Marañón, Huallaga, Ucayali) and the plain (Marañón, Tigre, Napo, Ucayali and Amazon rivers). Since 2003, the ORE-Hybam (IRD-SENAMHI-UNALM) observatory has performed out regular measurements at strategic points of the Amazon basin to understand and model the systems, behavior and long-term dynamics. On the Andean piedmont, the suspended yields are governed by a simple model with a relationship between the river discharge and the sediment concentration. In the plain, the dilution effect of the concentrations can create hysteresis in this relationship on a monthly basis. The Amazon basin of Peru has a sediment yield of 541 *106 t year-1, 70% comes from the southern basin.

  17. Freely suspended nanocomposite membranes as highly sensitive sensors.

    Science.gov (United States)

    Jiang, Chaoyang; Markutsya, Sergiy; Pikus, Yuri; Tsukruk, Vladimir V

    2004-10-01

    Highly sensitive sensor arrays are in high demand for prospective applications in remote sensing and imaging. Measuring microscopic deflections of compliant micromembranes and cantilevers is developing into one of the most versatile approaches for thermal, acoustic and chemical sensing. Here, we report on an innovative fabrication of compliant nanocomposite membranes with nanoscale thickness showing extraordinary sensitivity and dynamic range, which makes them candidates for a new generation of membrane-based sensor arrays. These nanomembranes with a thickness of 25-70 nm, which can be freely suspended over large (hundred micrometres) openings are fabricated with molecular precision by time-efficient, spin-assisted layer-by-layer assembly. They are designed as multilayered molecular composites made of a combination of polymeric monolayers and a metal nanoparticle intralayer. We demonstrate that these nanocomposite membranes possess unparalleled sensitivity and a unique autorecovering ability. The membrane nanostructure that is responsible for these outstanding properties combines multilayered polymer/nanoparticle organization, high polymer-chain orientation, and a pre-stretched state.

  18. Carbohydrate-Loading Diet

    Science.gov (United States)

    ... of your calories from carbohydrates. The role of carbohydrates Carbohydrates, also known as starches and sugars, are ... to consume some energy sources during your event. Carbohydrate loading Carbohydrate loading is done the week before ...

  19. How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments?

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@rmit.edu.a [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Zalizniak, Liliana [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Dunlop, Jason E. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia); Smart Water Research Facility, Griffith University, Queensland (Australia); Nugegoda, Dayanthi [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Choy, Satish C. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia)

    2010-02-15

    The effects of suspended and deposited sediments on the macroinvertebrates are well documented in upland streams but not in slower flowing lowland rivers. Using species found in lowland lotic environments, we experimentally evaluate mechanisms for sediments to affect macroinvertebrates, and in one experiment whether salinity alters the effect of suspended sediments. Suspended kaolin clay reduced feeding of Ischnura heterosticta (Odonata: Coenagrionidae) at high turbidity (1000-1500 NTU) but had no effects on feeding of Hemianax papuensis (Odonata: Aeshnidae) and Micronecta australiensis (Hemiptera: Corixidae). In freshwater (0.1 mS/cm), survival of Ischnura aurora was poor in clear water, but improved with suspended kaolin. Growth and feeding of I. aurora were unaffected by suspended sediments and salinity. Burial (1-5 mm) of eggs with kaolin or sand reduced hatching in Physa acuta (Gastropoda: Physidae), Gyraulus tasmanica (Gastropoda: Planorbidae) and Chironomus cloacalis (Diptera: Chironomidae). Settling sediments may pose greater risk to lowland lotic invertebrates than suspended sediments. - Sediment deposition may be more directly detrimental to macroinvertebrates of lowland rivers than suspended sediments.

  20. Collection Development.

    Science.gov (United States)

    School Libraries in Canada, 2002

    2002-01-01

    Includes 21 articles that discuss collection development in Canadian school libraries. Topics include digital collections in school library media centers; print and electronic library resources; library collections; collaborative projects; print-disabled students; informing administrators of the importance of collection development; censorship;…

  1. Use of Pollutant Load Regression Models with Various Sampling Frequencies for Annual Load Estimation

    OpenAIRE

    Youn Shik Park; Bernie A. Engel

    2014-01-01

    Water quality data are collected by various sampling frequencies, and the data may not be collected at a high frequency nor over the range of streamflow conditions. Therefore, regression models are used to estimate pollutant data for days on which water quality data were not measured. Pollutant load regression models were evaluated with six sampling frequencies for daily nitrogen, phosphorus, and sediment data. Annual pollutant load estimates exhibited various behaviors by sampling frequency...

  2. Mucous Secretion and Cilia Beating Defend Developing Coral Larvae from Suspended Sediments.

    Directory of Open Access Journals (Sweden)

    Gerard F Ricardo

    Full Text Available Suspended sediments produced from dredging activities, or added to the sediment budget via river runoff, are a concern for marine resource managers. Understanding the impact of suspended sediments on critical life history stages of keystone species like corals is fundamental to effective management of coastlines and reefs. Coral embryos (Acropora tenuis and A. millepora and larvae (A. tenuis, A. millepora and Pocillopora acuta were subjected to a range of suspended sediment concentrations of different sediment types (siliciclastic and carbonate to assess concentration-response relationships on ecologically relevant endpoints, including survivorship and ability to metamorphose. Embryos were subjected to short (12 h suspended sediment exposures from ages of 3-12 hours old or a long (30 h exposure at 6 hours old. Neither the survivorship nor metamorphosis function of embryos were significantly affected by realistic sediment exposures to ~1000 mg L-1. However, some embryos exhibited a previously undescribed response to dynamically suspended sediments, which saw 10% of the embryos form negatively buoyant cocoons at siliciclastic suspended sediment concentrations ≥35 mg L-1. Scanning electron and optical microscopy confirmed the presence of a coating on these embryos, possibly mucus with incorporated sediment particles. Cocoon formation was common in embryos but not in larvae, and occurred more often after exposure to siliciclastic rather than carbonate sediments. Once transferred into sediment-free seawater, functional ~36-h-old embryos began emerging from the cocoons, coinciding with cilia development. Ciliated (> 36-h-old larvae exposed to suspended sediments for 60 h were also observed to secrete mucus and were similarly unaffected by suspended sediment concentrations to ~800 mg L-1. This study provides evidence that mucous secretion and cilia beating effectively protect coral embryos and larvae from suspended sediment and that these mechanisms

  3. 40 CFR 1042.330 - Selling engines from an engine family with a suspended certificate of conformity.

    Science.gov (United States)

    2010-07-01

    ... with a suspended certificate of conformity. 1042.330 Section 1042.330 Protection of Environment... engines from an engine family with a suspended certificate of conformity. You may sell engines that you produce after we suspend the engine family's certificate of conformity under § 1042.315 only if one of the...

  4. 5 CFR 1620.45 - Suspending TSP loans, restoring post-employment withdrawals, and reversing taxable distributions.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Suspending TSP loans, restoring post... Employment and Reemployment Rights Act (USERRA)-Covered Military Service § 1620.45 Suspending TSP loans, restoring post-employment withdrawals, and reversing taxable distributions. (a) Suspending TSP loans during...

  5. Channel catfish hatchery production efficiency using a vertical-lift incubator the see-saw at various egg loading densities

    Science.gov (United States)

    Channel catfish spawns are typically incubated in ¼-in mesh baskets suspended in water that is agitated with paddles positioned between baskets. We tested a new vertical-lift incubator (the “See-Saw”) to incubate channel catfish spawns. Previous research demonstrated that when loaded with spawns at...

  6. Selection of HIV resistance associated with antiretroviral therapy initiated due to pregnancy and suspended postpartum.

    Science.gov (United States)

    Ellis, Giovanina M; Huang, Sharon; Hitti, Jane; Frenkel, Lisa M

    2011-11-01

    Compare the risk of HIV drug resistance in women stopping suppressive nelfinavir (NFV)-based or Nevirapine (NVP)-based antiretroviral therapy (ART) after pregnancy. Specimens collected after stopping ART were tested for drug resistance by an oligonucleotide ligation assay and consensus sequencing. When postpartum drug resistance was detected, specimens obtained at study entry and during ART were evaluated. Sixteen of 38 women with ART-induced suppression of viral replication suspended ART postpartum. Resistance mutations were detected in 75% who stopped NFV-ART and in 50% who stopped NVP-ART. M184V, associated with Lamivudine resistance, was more frequent among those randomized to NFV-ART compared with NVP-ART (6 of 8 versus 1 of 8; P = 0.04), and nonnucleoside reverse transcriptase inhibitor resistance was detected in 4 of 8 stopping NVP-ART. HIV drug resistance was frequently observed among women who stopped suppressive NVP-ART or NFV-ART postpartum. This suggests that NFV-ART may have suboptimal potency, that staggering discontinuation of NVP-ART may be warranted, and/or ART adherence may be lax in women who choose to stop ART postpartum.

  7. [Chemical Compositions and Sources Apportionment of Re-suspended Dust in Jincheng].

    Science.gov (United States)

    Wang, Yan; Peng, Lin; Li, Li-juan; Zhang, Teng; Liu, Hai-li; Mu, Ling

    2016-01-15

    In order to make effective plan to provide the scientific basis for prevention and control of re-suspended dust (RD), samples of particulate sources including RD and other pollution sources of Jincheng were collected. Elements, ions and carbon in particulate sources were analyzed. Enrichment factor, potential ecological risk assessment, and chemical mass balance model were used to analyze the chemical composition and the source of RD. The result indicated that the main components in RD of Jingeheng were Si, TC, Ca, OC, Al, Mg, Na, Fe, K and SO4(2-), contributing 61.14% of total mass of RD. The most abundant content of RD was crustal elements, and the ions were enriched in the fine particles. The mass fraction of OC in PM2. was higher, whereas the mass fraction of EC in PM10 was higher, indicating that secondary organic pollutants were mainly dominated in the fine particles. The dust PM2.5 and PM10 potential ecological risk indexes were extremely strong, and PM2.5 had higher ecological harm than PM10. Pb had the highest enrichment factor of 196.97 in PM2.5, which was followed by As, Cr, Ni, V, Zn and Cu, the enrichment factors of which were all greater than 10, indicating that they were apparently enriched and affected by human activities. Soil dust, construction dust, vehicle exhaust, and coal dust were the main sources of RD.

  8. H2S induces a suspended animation-like state in mice.

    Science.gov (United States)

    Blackstone, Eric; Morrison, Mike; Roth, Mark B

    2005-04-22

    Mammals normally maintain their core body temperature (CBT) despite changes in environmental temperature. Exceptions to this norm include suspended animation-like states such as hibernation, torpor, and estivation. These states are all characterized by marked decreases in metabolic rate, followed by a loss of homeothermic control in which the animal's CBT approaches that of the environment. We report that hydrogen sulfide can induce a suspended animation-like state in a nonhibernating species, the house mouse (Mus musculus). This state is readily reversible and does not appear to harm the animal. This suggests the possibility of inducing suspended animation-like states for medical applications.

  9. Electromechanical coupling in suspended nanomechanical resonators with a two-dimensional electron gas

    Science.gov (United States)

    Shevyrin, A. A.; Pogosov, A. G.; Bakarov, A. K.; Shklyaev, A. A.

    2017-06-01

    A physical model describing the piezoelectric-effect-mediated influence of bending of a thin suspended cantilever with a two-dimensional electron gas on the conductivity is proposed. The model shows that the conductivity change is almost entirely caused by the rapid change in mechanical stress near the boundary of suspended and non-suspended areas, rather than by the stress itself. An experiment confirming that the electromechanical coupling is associated with the piezoelectric effect is performed. The experimentally measured conductance sensitivity to the cantilever’s vibrations agree with the developed physical model.

  10. Estimation of suspended sediment concentration from Acoustic Doppler Current Profiler (ADCP) instrument: A case study of Lembeh Strait, North Sulawesi

    Science.gov (United States)

    Dwinovantyo, Angga; Manik, Henry M.; Prartono, Tri; Susilohadi; Ilahude, Delyuzar

    2017-01-01

    Measurement of suspended sediment concentration (SSC) is one of the parameters needed to determine the characteristics of sediment transport. However, the measurement of SSC nowadays still uses conventional technique and it has limitations; especially in temporal resolution. With advanced technology, the measurement can use hydroacoustic technology such as Acoustic Doppler Current Profiler (ADCP). ADCP measures the intensity of backscatter as echo intensity unit from sediment particles. The frequency of ADCP used in this study was 400 kHz. The samples were measured and collected from Lembeh Strait, North Sulawesi. The highest concentration of suspended sediment was 98.89 mg L-1 and the lowest was 45.20 mg L-1. Time series data showed the tidal condition affected the SSC. From the research, we also made correction from sound signal losses effect such as spherical spreading and sound absorption to get more accurate results by eliminating these parameters in echo intensity data. Simple linear regression analysis at echo intensity measured from ADCP to direct measurement of SSC was performed to obtain the estimation of the SSC. The comparison result of estimation of SSC from ADCP measurements and SSC from laboratory analyses was insignificantly different based on t-test statistical analysis with 95% confidence interval percentage.

  11. Influence of Rainfall Characteristics on Total Suspended Solids in Urban Runoff: A Case Study in Beijing, China

    Directory of Open Access Journals (Sweden)

    Yongwei Gong

    2016-07-01

    Full Text Available An urban rainfall-runoff water quality model was developed to simulate total suspend solids (TSS using the stormwater management model (SWMM for a 3.8 ha university campus in Beijing (approximately 76.5% impervious, and calibrated and validated against data from two observed rainfall events (221.2 and 16.6 mm rainfall. Model performance is satisfactory (Nash–Sutcliffe model efficiency 0.8 and 0.72 for flow and 0.74 and 0.51 for TSS concentration, respectively. A series of sensitivity model runs were conducted using the calibrated SWMM to study the influences of rainfall characteristics (rainfall hyetographs, depths and durations and surface flooding on the TSS concentration in outlet runoff of the catchment. The Pilgrim and Cordery rainfall distribution defines a first-quartile storm (the most severe and results in the highest peak discharge and TSS concentration at the outlet but the lowest outlet TSS load because of the highest TSS flood loss (32.3%. The simulated TSS pollutograph resulting from the Keifer and Chu rainfall distribution (with r = 0.5 is almost identical to that resulting from the alternating block rainfall distribution. Under the same rainfall hyetograph, simulated peak discharge and outlet TSS load are positively correlated (R2 = 0.95 to the rainfall depth as a function of the return period.

  12. Spatial electric load forecasting

    CERN Document Server

    Willis, H Lee

    2002-01-01

    Spatial Electric Load Forecasting Consumer Demand for Power and ReliabilityCoincidence and Load BehaviorLoad Curve and End-Use ModelingWeather and Electric LoadWeather Design Criteria and Forecast NormalizationSpatial Load Growth BehaviorSpatial Forecast Accuracy and Error MeasuresTrending MethodsSimulation Method: Basic ConceptsA Detailed Look at the Simulation MethodBasics of Computerized SimulationAnalytical Building Blocks for Spatial SimulationAdvanced Elements of Computerized SimulationHybrid Trending-Simulation MethodsAdvanced

  13. Cognitive Load and Cooperation

    DEFF Research Database (Denmark)

    Døssing, Felix Sebastian; Piovesan, Marco; Wengström, Erik Roland

    2017-01-01

    We study the effect of intuitive and reflective processes on cooperation using cognitive load. Compared with time constraint, which has been used in the previous literature, cognitive load is a more direct way to block reflective processes, and thus a more suitable way to study the link between...... intuition and cooperation. Using a repeated public goods game, we study the effect of different levels of cognitive load on contributions. We show that a higher cognitive load increases the initial level of cooperation. In particular, subjects are significantly less likely to fully free ride under high...... cognitive load....

  14. An investigation into the effectiveness of sand media amended with biochar to remove BOD5, suspended solids and coliforms using wetland mesocosms.

    Science.gov (United States)

    de Rozari, P; Greenway, M; El Hanandeh, A

    2015-01-01

    Constructed wetland ecotechnologies (CWEs) are a promising solution to effectively treat domestic wastewater in developing countries at low cost. This paper reports the findings of the effectiveness of sand media amended with woody biochar and two plants species (Melaleuca quinquenervia and Cymbopogon citratus) in removing biological oxygen demand (BOD5), suspended solids and coliforms. The experimental design consisted of 21 vertical flow (VF) mesocosms. There were seven media treatments using sand amended with varying proportions of biochar. During the first 8 months, the mesocosms were loaded with secondary clarified wastewater (SCW) then septage. The influent had a 4-day hydraulic retention time. Samples were monitored for BOD5, total suspended solids (TSS), total volatile solids (TVS), total coliforms and faecal coliforms. In the first 8 months, there were no significant performance differences between media treatments in the outflow concentrations of BOD5, TSS and TVS. The significant differences occurred during the last 3 months; using septage with biochar additions performed better than pure sand. For coliforms, the significant differences occurred after 6 months. In conclusion, the addition of biochar was not effective for SCW. The VF mesocosms system proved to be more effective in removing BOD5, TSS, TVS and coliforms when septage was loaded into the media.

  15. Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Augusto França Schettini

    2010-03-01

    Full Text Available The circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearly-synoptic hourly hydrographic, current (ADCP velocity and volume transport and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms-1 were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms-1 and the peak flood currents were 0.75 and 0.60 ms-1, respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified and Type 1a (well mixed. Volume transports were very close, ranging from -3,500 to 3,100 m³s-1 at the ebb and flood, respectively, with a residual -630 m³s-1. The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg.L-1 at the estuary mouth, to 10 mg.L-1 at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle.A circulação e o transporte de material particulado em suspensão no Estuário de Caravelas são pesquisados. Dados quase-sinóticos hidrográficos, de correntes (velocidade e transporte de volume com ADCP e de material particulado em suspensão, foram medidos em intervalos horários durante um ciclo semidiurno de maré de sizígia, em duas seções transversais na Boca do Tomba e na Barra Velha e também em seções longitudinais na baixa-mar e na preamar. Na primeira transversal as correntes máximas de vazante (-1,50 m s-1 foram quase duas vezes mais intensas do que na seção transversal mais larga e rasa Barra Velha, (-0,80 m s-1 e as maiores velocidades das correntes de

  16. PASSIVE DETECTION OF VEHICLE LOADING

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, A.

    2012-01-03

    The Digital Imaging and Remote Sensing Laboratory (DIRS) at the Rochester Institute of Technology, along with the Savannah River National Laboratory is investigating passive methods to quantify vehicle loading. The research described in this paper investigates multiple vehicle indicators including brake temperature, tire temperature, engine temperature, acceleration and deceleration rates, engine acoustics, suspension response, tire deformation and vibrational response. Our investigation into these variables includes building and implementing a sensing system for data collection as well as multiple full-scale vehicle tests. The sensing system includes; infrared video cameras, triaxial accelerometers, microphones, video cameras and thermocouples. The full scale testing includes both a medium size dump truck and a tractor-trailer truck on closed courses with loads spanning the full range of the vehicle's capacity. Statistical analysis of the collected data is used to determine the effectiveness of each of the indicators for characterizing the weight of a vehicle. The final sensing system will monitor multiple load indicators and combine the results to achieve a more accurate measurement than any of the indicators could provide alone.

  17. Static ice loads on hydro-electric structures: ice load monographs: Volume 1: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Comfort, G.; Abdelnour, R.; Gong, Y.; Dinovitzer, A.

    1996-07-01

    Ice loads on hydro-electric structures were measured during a four-year field program. Loads were measured at Hydro-Quebec`s Paugan dam, Ontario Hydro`s Arnprior and Otto Holden dams, and in a large outdoor basin at the National Research Council (NRC) during one winter. Ice loads were measured in the reservoir ice sheet, near the concrete face of the dam, and near the gate and pier of the Paugan dam. Ice stresses were measured continuously by stressmeters that were deployed in the ice. Loads at the Paugan dam and the NRC basin resulted mostly from ice temperature changes. The loads at the Arnprior and Otto Holden dams were produced by a combination of ice temperature and water level changes. The collected data was analyzed in detail and efforts were made to improve techniques for predicting ice loads. Significant progress was made towards the development of detailed, quantitative understanding of static ice loads on hydro-electric structures, and the factors controlling them. However, the ice load predictors are subject to a number of limitations and further work is required before changes to design practices can be recommended with confidence. More field data collection would also improve the definition of loads arising from a combination of water level and ice temperature changes. Additional numerical analyses was also recommended to better define the effects of ice confinement. Appendices were published separately in volume 2 of this report. 43 refs., 18 tabs., 96 figs.

  18. Comparison of the efficiencies of attached- versus suspended-growth SBR systems in the treatment of recycled paper mill wastewater.

    Science.gov (United States)

    Muhamad, Mohd Hafizuddin; Sheikh Abdullah, Siti Rozaimah; Abu Hasan, Hassimi; Abd Rahim, Reehan Adnee

    2015-11-01

    The complexity of residual toxic organics from biologically treated effluents of pulp and paper mills is a serious concern. To date, it has been difficult to choose the best treatment technique because each of the available options has advantages and drawbacks. In this study, two different treatment techniques using laboratory-scale aerobic sequencing batch reactors (SBRs) were tested with the same real recycled paper mill effluent to evaluate their treatment efficiencies. Two attached-growth SBRs using granular activated carbon (GAC) with and without additional biomass and a suspended-growth SBR were used in the treatment of real recycled paper mill effluent at a chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 h and a COD:N:P ratio of approximately 100:5:1. The efficiency of this biological treatment process was studied over a 300-day period. The six most important wastewater quality parameters, namely, chemical oxygen demand (COD), turbidity, ammonia (expressed as NH3-N), phosphorus (expressed as PO4(3)-P), colour, and suspended solids (SS), were measured to compare the different treatment techniques. It was determined that these processes were able to almost completely and simultaneously eliminate COD (99%) and turbidity (99%); the removals of NH3-N (90-100%), PO4(3)-P (66-78%), colour (63-91%), and SS (97-99%) were also sufficient. The overall performance results confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of performance efficiency and process stability under fluctuations of organic load. Hence, this hybrid system is recommended for the treatment of pulp and paper mill effluents. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Residual fluxes of water, salt and suspended sediment in the Beypore Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; Revichandran, C.; Sankaranarayanan, V.N.; Josanto, V.

    The monthly trends of the residual fluxes of salt and water and the transportation of suspended sediments in the Beypore estuarine system, Kerala, India were examined. At the river mouth the water flux was directed seaward during the postmonsoon...

  20. Suspended sediment fluxes in a tropical estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; DineshKumar, P.K.; Srinivas, K.

    Annual transport processes of suspended sediments in Beypore estuary - a tropical estuary along the south west coast of India - were investigated based on time series measurements within the system. It's observed that the sediment transport...

  1. Evaluation of Spinacia oleracea L. leaves mucilage as an innovative suspending agent.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Pany, Dipti Ranjan; Mohanty, Biswaranjan

    2010-07-01

    The present study was undertaken to evaluate the mucilage isolated from Spinacia oleracea L. leaves, commonly named spinach (family: Amaranthaceae) as an innovative suspending agent. Zinc oxide suspensions (20% w/v) were prepared using the mucilage of S. oleracea L. leaves as a suspending agent, and it was evaluated for its stability by using parameters like, sedimentation profile, degree of flocculation, and redispersibility. The effect of the tested mucilage on the suspension was compared with various commonly used suspending agents, such as, tragacanth, bentonite, and sodium carboxymethyl cellulose (NaCMC) at concentrations of 0.5, 1.0, and 2.0% w/v. The results obtained indicated that the mucilage of S. oleracea L. leaves could be used as a suspending agent, and the performance was found to be superior to both tragacanth and bentonite.

  2. Evaluation of Spinacia oleracea L. leaves mucilage as an innovative suspending agent

    Directory of Open Access Journals (Sweden)

    Amit Kumar Nayak

    2010-01-01

    Full Text Available The present study was undertaken to evaluate the mucilage isolated from Spinacia oleracea L. leaves, commonly named spinach (family: Amaranthaceae as an innovative suspending agent. Zinc oxide suspensions (20% w/v were prepared using the mucilage of S. oleracea L. leaves as a suspending agent, and it was evaluated for its stability by using parameters like, sedimentation profile, degree of flocculation, and redispersibility. The effect of the tested mucilage on the suspension was compared with various commonly used suspending agents, such as, tragacanth, bentonite, and sodium carboxymethyl cellulose (NaCMC at concentrations of 0.5, 1.0, and 2.0% w/v. The results obtained indicated that the mucilage of S. oleracea L. leaves could be used as a suspending agent, and the performance was found to be superior to both tragacanth and bentonite.

  3. 76 FR 80982 - International Cyclotron, Inc., Hato Rey, Puerto Rico; Order Suspending Licensed Activities

    Science.gov (United States)

    2011-12-27

    ...-0292] International Cyclotron, Inc., Hato Rey, Puerto Rico; Order Suspending Licensed Activities I International Cyclotron, Inc. (International Cyclotron; Licensee) is the holder of Byproduct Materials License... International Cyclotron submitted its NRC license application related to the cyclotron, it requested...

  4. Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland

    NARCIS (Netherlands)

    Overeem, I.; Hudson, Brian D; Syvitski, James P. M.; Mikkelsen, Andreas B.; Hasholt, B.; van den Broeke, M. R.; Noel, B. P. Y.; Morlighem, M.

    2017-01-01

    Limited measurements along Greenland’s remote coastline hamper quantification of the sediment and associated nutrients draining the Greenland ice sheet, despite the potential influence of river-transported suspended sediment on phytoplankton blooms and carbon sequestration. Here we calibrate

  5. Seasonal variations of total suspended matter (TSM) in the Gulf of Khambhat, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Misra, A.; ManiMurali, R.; Sukumaran, S.; Vethamony, P.

    Total Suspended Matter (TSM)is an important parameter for determining the water quality in coastal regions as it is responsible for the reduction in the light available to the aquatic vegetation which subsequently alters the health and quality...

  6. Natural isotopic composition of nitrogen in suspended particulate matter in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, S.; Ramesh, R.; Bhosle, N.B.; Sardessai, S.; Sheshshayee, M.S.

    The first measurements of nitrogen isotopic composition (delta sup(15) N) in suspended particulate matter (SPM) of the surface Bay of Bengal (BOB) at 24 different locations during pre- (April-May 2003) and post- (September-October 2002) monsoon...

  7. Experimental realization of suspended atomic chains composed of different atomic species

    Energy Technology Data Exchange (ETDEWEB)

    Bettini, Jefferson; Ugarte, Daniel [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil); Sato, Fernando; Galvao, Douglas Soares [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin; Coura, Pablo Zimmerman; Dantas, Socrates de Oliveira [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Inst. de Ciencias Exatas. Dept. de Fisica

    2006-07-01

    We report high resolution transmission electron microscopy (HRTEM) and molecular dynamics results of the first experimental test of suspended atomic chains composed of different atomic species formed from spontaneous stretching of metallic nanowires. (author)

  8. The Statistical Properties of Host Load

    Directory of Open Access Journals (Sweden)

    Peter A. Dinda

    1999-01-01

    Full Text Available Understanding how host load changes over time is instrumental in predicting the execution time of tasks or jobs, such as in dynamic load balancing and distributed soft real‐time systems. To improve this understanding, we collected week‐long, 1 Hz resolution traces of the Digital Unix 5 second exponential load average on over 35 different machines including production and research cluster machines, compute servers, and desktop workstations. Separate sets of traces were collected at two different times of the year. The traces capture all of the dynamic load information available to user‐level programs on these machines. We present a detailed statistical analysis of these traces here, including summary statistics, distributions, and time series analysis results. Two significant new results are that load is self‐similar and that it displays epochal behavior. All of the traces exhibit a high degree of self‐similarity with Hurst parameters ranging from 0.73 to 0.99, strongly biased toward the top of that range. The traces also display epochal behavior in that the local frequency content of the load signal remains quite stable for long periods of time (150–450 s mean and changes abruptly at epoch boundaries. Despite these complex behaviors, we have found that relatively simple linear models are sufficient for short‐range host load prediction.

  9. Hood River Conservation Project load analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, T.K.

    1987-11-01

    As a part of the Hood River Conservation Project (HRCP), 314 homes were monitored to measure electrical energy use. The total electrical load, space heating load, water heating load (in about 200 homes), wood-stove heat output (in about 100 homes), and indoor temperature were monitored. Data were collected for one full year before and one full year after these homes were retrofit with conservation measures. Local weather information was also collected on a 15-min basis. This data base was used to evaluate the load savings attributable to HRCP. Two methods of weather normalization were used and showed close agreement. The weather-normalized diversified residential load savings on the Pacific Power and Light system and Hood River area peak days were >0.5 kW/household. The average spring, summer, and fall savings were much smaller, <0.1 kW/household. The load factor for the diversified residential load decreased following the conservation retrofit actions. 11 refs., 40 figs., 13 tabs.

  10. Optimisation of load control

    Energy Technology Data Exchange (ETDEWEB)

    Koponen, P. [VTT Energy, Espoo (Finland)

    1998-08-01

    Electricity cannot be stored in large quantities. That is why the electricity supply and consumption are always almost equal in large power supply systems. If this balance were disturbed beyond stability, the system or a part of it would collapse until a new stable equilibrium is reached. The balance between supply and consumption is mainly maintained by controlling the power production, but also the electricity consumption or, in other words, the load is controlled. Controlling the load of the power supply system is important, if easily controllable power production capacity is limited. Temporary shortage of capacity causes high peaks in the energy price in the electricity market. Load control either reduces the electricity consumption during peak consumption and peak price or moves electricity consumption to some other time. The project Optimisation of Load Control is a part of the EDISON research program for distribution automation. The following areas were studied: Optimization of space heating and ventilation, when electricity price is time variable, load control model in power purchase optimization, optimization of direct load control sequences, interaction between load control optimization and power purchase optimization, literature on load control, optimization methods and field tests and response models of direct load control and the effects of the electricity market deregulation on load control. An overview of the main results is given in this chapter

  11. A study of metal ion adsorption at low suspended-solid concentrations

    Science.gov (United States)

    Chang, Cecily C.Y.; Davis, J.A.; Kuwabara, J.S.

    1987-01-01

    A procedure for conducting adsorption studies at low suspended solid concentrations in natural waters (NaCl) concentration (0??1-0??002 m) and particle concentration (2-50 mg l-1). The lack of success of the Davis Leckie site bonding model in describing Zn(II) adsorption emphasizes the need for further studies of adsorption at low suspended-solid concentrations. ?? 1987.

  12. Wavelength-Tunable IR Detector based on Suspended Bilayer Graphene Micro Ribbons

    Science.gov (United States)

    2013-11-05

    high purity copper foil using a low pressure CVD furnace at 1000 oC in a hydrogen, argon and methane environment. Raman spectrum of the graphene ...characterized in Year One a device with suspended graphene microribbons, and found that fully suspended CVD -grown graphene devices are dominated by the...photoelectric effect, which is promising towards CVD -grown graphene photodetectors approaching THz cut-off frequencies. chemical vapor deposition, strain

  13. Measurement of Suspended Sediment Transport Processes off the Holderness Coast - Southern North Sea, England

    OpenAIRE

    Blewett, Joanna Catherine

    1998-01-01

    A field campaign was set up as part of the LOIS-RACS coastal program (1994-1996), to identify the near-bed physical processes responsible for suspended sediment movement in shallow water (10-20m depth) off the Holdemess coast, NE England. A new benthic tripod system Boundary Layer Intelligent Sensor System (BLISS) has been developed and deployed along a transect at three sites, normal to the coastline at Tunstall. Measurements of current velocity, suspended sediment concentrati...

  14. Thermal instability of Walters B' viscoelastic fluid permeated with suspended particles in hydromagnetics in porous medium

    Directory of Open Access Journals (Sweden)

    Kumar Pardeep

    2004-01-01

    Full Text Available The effect of suspended particles on the thermal instability of Walters B' viscoelastic fluid in hydromantic in porous medium is considered. For stationary convection, Walters B' viscoelastic fluid behaves like a Newtonian fluid. The medium permeability and suspended particles has ten the onset of convection whereas the magnetic field postpones the onset of convection, for the case of stationary convection. The magnetic field and viscoelasticity intro duce oscillatory modes in the system which was non-existent in their absence.

  15. Spatial and temporal variability of suspended-sediment concentrations in a shallow estuarine environment

    Directory of Open Access Journals (Sweden)

    Catherine A. Ruhl

    2004-05-01

    Full Text Available Shallow subembayments respond differently than deep channels to physical forces acting in estuaries. The U.S. Geological Survey measured suspended-sediment concentrations at five locations in Honker Bay, a shallow subembayment of San Francisco Bay, and the adjacent channel to investigate the spatial and temporal differences between deep and shallow estuarine environments. During the first freshwater pulse of the wet season, the channel tended to transport suspended sediments through the system, whereas the shallow area acted as off-channel storage where deposition would likely occur. Following the freshwater pulse, suspended-sediment concentrations were greater in Honker Bay than in the adjacent deep channel, due to the larger supply of erodible sediment on the bed. However, the tidal variability of suspended-sediment concentrations in both Honker Bay and in the adjacent channel was greater after the freshwater pulse than before. During wind events, suspended-sediment concentrations in the channel were not affected; however, wind played a crucial role in the resuspension of sediments in the shallows. Despite wind-wave sediment resuspension in Honker Bay, tidally averaged suspended-sediment flux was controlled by the flood-dominated currents.

  16. SEASONAL DISTRIBUTION OF TOTAL SUSPENDED MATTER IN SUMBAWA SEA

    Directory of Open Access Journals (Sweden)

    IGAG SWANDANA

    2015-05-01

    Full Text Available Distribusi Musiman Total Suspended Matter (TSM di Laut Surnbawa (117" - us· Edan s· - 9· S telah dilakukan. Data TSM tersebut diperoleh dari 75 stasiun pengukuran pada bulan September 2005 dan 98 stasiun pengukuran pada bulan November 2005 dan April 2006. Besaran sebaran TSM diperoleh dari hasil perhitungan besaran turbidity yang diperoleh dari pengukuran dengan menggunakan alat CTD ( Conductivity, Temperature and Depth Sensors. Besaran TSM yang diperoleh dari besaran turbidity menggunakan rurnus TSM = 0,65 Tur+ 1,17 (r = 0,85 (Hoshika dan Tanimoto, 1997.  Distribusi sebaran TSM pada saat musim hujan menunjukkan bahwa besarnya bervariasi dari L060 sam­pai 2.951 mg/1 dengan rata-rata sebesar 1.152 mg/1 (n=98, di lain pihak pada saat musim kemarau distribusi sebaran TSM menunjukkan bahwa besarnya bervariasi dari 1.060 sampai 2.899 mg/1 dengan rata-rata sebesar 1.111 mg/I (n=75. Distribusi sebaran TSM secara vertical dari permukaan laut sampai dengan kedalaman 20 meter menunjukkan bahwa terjadi perbedaan yang signifikan antara musim kemarau dan musim hujan. Pada saat musim kemarau distribusi sebaran TSM pada permukaan laut sampai dengan kedalaman 20 meter mem­punyai variasi yang kecil (dari 1.079 sampai 1.599 mg/1; Pada saat musim hujan distribusi sebaran TSM pada permukaan laut sampai dengan kedalaman 20 meter mempunyai variasi yang sangat besar (dari 1.079 sampai 2.698 mg/1. Distribusi sebaran TSM dari kedalaman 20 meter sampai dengan 100 meter menunjukkan pola yang sama antara musim kemarau dan musim hujan.  Distribusi sebaran TSM pada permukaan laut (dekat sungai/muara menunjukkan bahwa terjadi perbedaan sebaran antara musim kemarau dan musim hujan. Demikian juga dengan distribusi sebaran TSM yang diper­oleh dari data satelit menunjukkan bahwa terjadi perbedaan sebaran antara musim kemarau dan musim hujan. Perbandingan antara data in situ dengan data satelit menunjukkan bahwa koefisen korelasinya sebesar -0-753 untuk periode penelitian

  17. Controls on suspended aggregate size in partially mixed estuaries

    Science.gov (United States)

    Fugate, David C.; Friedrichs, Carl T.

    2003-10-01

    Knowledge of aggregate size in estuaries is important to determining the fate and transport of suspended sediment and particle adherent contaminants. We have used a suite of in situ instruments to determine the controls of aggregate size distributions in three muddy, partially mixed estuaries in the mid-Atlantic USA. A novel method is presented to estimate turbulent kinetic energy (TKE) production and the resulting Kolmogorov microscale ( λK) using a profiling acoustic Doppler velocimeter that has been contaminated by boat motion. The physical processes that control particle size distribution differ in the three estuaries due to the different hydrodynamics and benthic characteristics. Controls within each estuary also vary with different depth regimes. Surface particle size dynamics in all the studied estuaries are affected by irregular advection events. In the hydrodynamically energetic York River, mid-depth regions are controlled tidally by the combined processes of small λK decreasing particle size at high TKE and differential settling increasing particle size during lower TKE, more stratified conditions. Mid-depth regions in the lower energy Elizabeth River are controlled by irregular resuspension and trapping at the pycnocline of large low density particles. Bottom regions in all estuaries are most strongly influenced by resuspension, tidally in the energetic estuaries and irregularly in the low energy estuary. Near-bed particle size distributions are controlled by both λK and the distribution of particles in the bed in the higher energy estuaries. Just above the bed, large porous particles survive resuspension in the lower energy Elizabeth River, particles become smaller with decreased λK in the more energetic York River, and biological aggregation causes large dense particles to resist turbulent breakup in the Chesapeake Bay, which has a more active benthic community. The net result just above the bed is that particle size and settling velocity are

  18. Appropriate maximum holding times for analysis of total suspended solids concentration in water samples taken from open-channel waterways.

    Science.gov (United States)

    Oudyn, Frederik W; Lyons, David J; Pringle, M J

    2012-01-01

    Many scientific laboratories follow, as standard practice, a relatively short maximum holding time (within 7 days) for the analysis of total suspended solids (TSS) in environmental water samples. In this study we have subsampled from bulk water samples stored at ∼4 °C in the dark, then analysed for TSS at time intervals up to 105 days after collection. The nonsignificant differences in TSS results observed over time demonstrates that storage at ∼4 °C in the dark is an effective method of preserving samples for TSS analysis, far past the 7-day standard practice. Extending the maximum holding time will ease the pressure on sample collectors and laboratory staff who until now have had to determine TSS within an impractically short period.

  19. Individual particle analysis of coarse air suspended particulate material by synchrotron radiation X-ray micro fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana; Melo Junior, Ariston [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo. Dept. de Recursos Hidricos]. E-mail: silvana@fec.unicamp.br; Perez, Carlos Alberto [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)]. E-mail: perez@lnls.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Nascimento Filho, Virgilio F. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Instrumentacao Nuclear]. E-mail: virgilio@cena.usp.br

    2005-07-01

    The purpose of this work is evaluate the size of individual particles present in the air suspended particulate material collected in Campinas, Sao Paulo State, and analyze quantitatively the particles using the synchrotron radiation X-ray micro fluorescence ({mu}-SRXRF) associated with the fundamental parameter method to correct attenuation/absorption effects by the matrix. The particles analyzed have size between 50-10 {mu}m and to perform the spatial distribution a white beam of synchrotron radiation condensed by a conical capillary (13 {mu}m diameter) was used. For the quantitative analysis punctual measures in thin films standards in Mylar subtract were performed. The elements detected were Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ba and Pb. (author)

  20. Concentrated loads on concrete

    DEFF Research Database (Denmark)

    Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter

    1997-01-01

    This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are devel......This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas...

  1. Electrical load modeling

    Energy Technology Data Exchange (ETDEWEB)

    Valgas, Helio Moreira; Pinto, Roberto del Giudice R.; Franca, Carlos [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Lambert-Torres, Germano; Silva, Alexandre P. Alves da; Pires, Robson Celso; Costa Junior, Roberto Affonso [Escola Federal de Engenharia de Itajuba, MG (Brazil)

    1994-12-31

    Accurate dynamic load models allow more precise calculations of power system controls and stability limits, which are critical mainly in the operation planning of power systems. This paper describes the development of a computer program (software) for static and dynamic load model studies using the measurement approach for the CEMIG system. Two dynamic load model structures are developed and tested. A procedure for applying a set of measured data from an on-line transient recording system to develop load models is described. (author) 6 refs., 17 figs.

  2. Critical Axial Load

    Directory of Open Access Journals (Sweden)

    Walt Wells

    2008-01-01

    Full Text Available Our objective in this paper is to solve a second order differential equation for a long, simply supported column member subjected to a lateral axial load using Heun's numerical method. We will use the solution to find the critical load at which the column member will fail due to buckling. We will calculate this load using Euler's derived analytical approach for an exact solution, as well as Euler's Numerical Method. We will then compare the three calculated values to see how much they deviate from one another. During the critical load calculation, it will be necessary to calculate the moment of inertia for the column member.

  3. Discharge, suspended sediment, and salinity in the Gulf Intracoastal Waterway and adjacent surface waters in South-Central Louisiana, 1997–2008

    Science.gov (United States)

    Swarzenski, Christopher M.; Perrien, Scott M.

    2015-10-19

    Discharge, suspended sediment, and salinity data collected between 1997 and 2008 indicate that the Gulf Intracoastal Waterway (GIWW) is an important distributary of river water and suspended sediments to coastal wetlands in south-central coastal Louisiana. Following natural hydraulic gradients, the GIWW passively distributes freshwater and suspended sediments from the Atchafalaya River to areas at least 30 to 50 miles west and east, respectively, of Morgan City. The magnitude and reach of the discharge in the GIWW increase as stage of the Wax Lake Outlet at Calumet and Lower Atchafalaya River (LAR) at Morgan City increase. The magnitude and duration of discharge vary from year to year depending on the flow regime of the Atchafalaya River. Annual discharge of water in the GIWW was greater during years when stage of the LAR remained anomalously high throughout the year, compared with average and peak flood years. During years when Atchafalaya River flow is low, Bayou Boeuf, a waterway draining the Verret subbasin, becomes a major source of water maintaining the eastward flow in the GIWW. The GIWW is the only means of getting river water to some parts of coastal Louisiana.

  4. Status and trends in suspended-sediment discharges, soil erosion, and conservation tillage in the Maumee River basin--Ohio, Michigan, and Indiana

    Science.gov (United States)

    Myers, Donna N.; Metzker, Kevin D.; Davis, Steven

    2000-01-01

    The relation of suspended-sediment discharges to conservation-tillage practices and soil loss were analyzed for the Maumee River Basin in Ohio, Michigan, and Indiana as part of the U.S. Geological Survey?s National Water-Quality Assessment Program. Cropland in the basin is the largest contributor to soil erosion and suspended-sediment discharge to the Maumee River and the river is the largest source of suspended sediments to Lake Erie. Retrospective and recently-collected data from 1970-98 were used to demonstrate that increases in conservation tillage and decreases in soil loss can be related to decreases in suspended-sediment discharge from streams. Average annual water and suspended-sediment budgets computed for the Maumee River Basin and its principal tributaries indicate that soil drainage and runoff potential, stream slope, and agricultural land use are the major human and natural factors related to suspended-sediment discharge. The Tiffin and St. Joseph Rivers drain areas of moderately to somewhat poorly drained soils with moderate runoff potential. Expressed as a percentage of the total for the Maumee River Basin, the St. Joseph and Tiffin Rivers represent 29.0 percent of the basin area, 30.7 percent of the average-annual streamflow, and 9.31 percent of the average annual suspended-sediment discharge. The Auglaize and St. Marys Rivers drain areas of poorly to very poorly drained soils with high runoff potential. Expressed as a percentage of the total for the Maumee River Basin, the Auglaize and St. Marys Rivers represent 48.7 percent of the total basin area, 53.5 percent of the average annual streamflow, and 46.5 percent of the average annual suspended-sediment discharge. Areas of poorly drained soils with high runoff potential appear to be the major source areas of suspended sediment discharge in the Maumee River Basin. Although conservation tillage differed in the degree of use throughout the basin, on aver-age, it was used on 55.4 percent of all crop

  5. Effects of cadmium accumulation from suspended sediments and phytoplankton on the Oyster Saccostrea glomerata

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Helena A.; Maher, William A., E-mail: bill.maher@canberra.edu.au; Taylor, Anne M.; Krikowa, Frank

    2015-03-15

    Highlights: • Saccostrea glomerata accumulated cadmium from sediments and phytoplankton. • Effects were similar for both pathways. • Antioxidant capacity, lipid peroxidation and lysosomal destabilisation were affected. • Clear exposure–dose–response relationships were demonstrated. - Abstract: Metals are accumulated by filter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93 μg/g dry mass) and cadmium-enriched phytoplankton (1.6–3 μg/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treatments (5.9 ± 0.4 μg/g and 23 ± 2 μg/g respectively compared to controls 0.97 ± 0.05 μg/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9 ± 0.1 μg/g compared to controls 1.2 ± 0.1 μg/g). In the cadmium spiked suspended sediment experiments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were significantly related to dissolved cadmium concentrations (4–21 μg/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01 μg/L. In both exposure experiments, cadmium-exposed oysters showed a significant reduction in total antioxidant capacity and significantly increased lipid peroxidation and percentage of destabilised lysosomes. Destabilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata.

  6. Load Induced Blindness

    Science.gov (United States)

    Macdonald, James S. P.; Lavie, Nilli

    2008-01-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005, for a review). Here we varied the level of…

  7. Linking hysteresis patterns and variations in suspended sediment sources in a highly urbanized river: a case of the River Aire, UK

    Science.gov (United States)

    Vercruysse, Kim; Grabowski, Robert

    2017-04-01

    The natural sediment balance of rivers is often disturbed as a result of increased fine sediment influx from soil erosion and/or modifications to the river channel and floodplains, causing numerous problems related to ecology, water quality, flood risk and infrastructure. It is of great importance to understand fine sediment dynamics in rivers in order to manage the problems appropriately. However, despite decades of research, our understanding of fine sediment transport is not yet sufficient to fully explain the spatial and temporal variability in sediment concentrations in rivers. To this end, the study aims to investigate the importance of sediment source variations to explain hysteresis patterns in suspended sediment transport. A sediment fingerprinting technique based on infrared spectrometry was applied in the highly urbanized River Aire catchment in northern England to identify the dominant sources of suspended sediment. Three types of potential sediment source samples were collected: soil samples from pasture in three lithological areas (limestone, millstone grit and coal measures), eroding riverbanks and urban street dust. All source samples were analyzed with Diffuse Reflectance Infrared Fourier Transform spectrometry (DRIFTS). Discriminant analysis demonstrated that the source materials could be discriminated based on their respective infrared spectra. Infrared spectra of experimental mixtures were then used to develop statistical models to estimate relative source contributions from suspended sediment samples. Suspended sediment samples were collected during a set of high flow events between 2015 and 2016, showing different hysteresis patterns between suspended sediment concentration and discharge. The fingerprinting results suggest that pasture from the limestone area is the dominant source of fine sediment. However, significant variations in source contributions during and between events are present. Small events, in terms of discharge, are marked by

  8. Polybrominated diphenyl ethers in Mississippi River suspended sediment

    Energy Technology Data Exchange (ETDEWEB)

    Raff, J.; Hites, R. [Indiana Univ., Bloomington, IN (United States)

    2004-09-15

    The Mississippi River Basin drains water from 41% of the conterminous U.S. and is a valuable resource that supplies food, transportation, and irrigation to more than 95 million people of the region. Discharge and runoff from industry, agriculture, and population centers have increased the loads of anthropogenic organic compounds in the river. There has been growing concern over the rising levels of polybrominated diphenyl ethers (PBDEs) in air, sediment, biota, and humans, but there have been no studies to measure the concentrations of these chemicals in North America's largest river system. The goal of this study was to investigate the occurrence of PBDEs (15 congeners including BDE-209) and to identify possible sources within the Mississippi River Basin. We found PBDEs to be widespread throughout the region, rivaling PCBs in their extent and magnitude of contamination. We have also calculated the total amount of PBDEs released to the Gulf of Mexico in 2002.

  9. Quantifying Training Loads in Contemporary Dance.

    Science.gov (United States)

    Jeffries, Annie C; Wallace, Lee; Coutts, Aaron J

    2017-07-01

    To describe the training demands of contemporary dance and determine the validity of using the session rating of perceived exertion (sRPE) to monitor exercise intensity and training load in this activity. In addition, the authors examined the contribution of training (ie, accelerometry and heart rate) and non-training-related factors (ie, sleep and wellness) to perceived exertion during dance training. Training load and ActiGraphy for 16 elite amateur contemporary dancers were collected during a 49-d period, using heart-rate monitors, accelerometry, and sRPE. Within-individual correlation analysis was used to determine relationships between sRPE and several other measures of training intensity and load. Stepwise multiple regressions were used to determine a predictive equation to estimate sRPE during dance training. Average weekly training load was 4283 ± 2442 arbitrary units (AU), monotony 2.13 ± 0.92 AU, strain 10677 ± 9438 AU, and average weekly vector magnitude load 1809,707 ± 1015,402 AU. There were large to very large within-individual correlations between training-load sRPE and various other internal and external measures of intensity and load. The stepwise multiple-regression analysis also revealed that 49.7% of the adjusted variance in training-load sRPE was explained by peak heart rate, metabolic equivalents, soreness, motivation, and sleep quality (y = -4.637 + 13.817%HR peak + 0.316 METS + 0.100 soreness + 0.116 motivation - 0.204 sleep quality). The current findings demonstrate the validity of the sRPE method for quantifying training load in dance, that dancers undertake very high training loads, and a combination of training and nontraining factors contribute to perceived exertion in dance training.

  10. Evaluation of the Suspending Properties of the Co- precipitate of ...

    African Journals Online (AJOL)

    Pharmaceutical Ltd, Benin City, Nigeria. Irvingia gabonensis seeds were collected in the month of. May and identified by Mr. Sunday Nweke of the. Department of Pharmacognosy, University of. Benin, Nigeria. A voucher specimen. (UBH_I0153) of the seed has been kept in the herbarium of the Department of Plant Biology.

  11. Collective Enumeration

    Science.gov (United States)

    Bahrami, Bahador; Didino, Daniele; Frith, Chris; Butterworth, Brian; Rees, Geraint

    2013-01-01

    Many joint decisions in everyday life (e.g., Which bar is less crowded?) depend on approximate enumeration, but very little is known about the psychological characteristics of counting together. Here we systematically investigated collective approximate enumeration. Pairs of participants made individual and collective enumeration judgments in a…

  12. Data collection

    NARCIS (Netherlands)

    Callaert, J.; Epping, Elisabeth; Federkeil, G.; Jongbloed, Benjamin W.A.; Kaiser, Franciscus; Tijssen, R.; van Vught, F.A.; Ziegele, F.

    2012-01-01

    This chapter describes the data collection instruments used in the development of U-Multirank. The first section is an overview of existing databases – mainly on bibliometrics and patents. The second describes the questionnaires and survey tools used for collecting data from the institutions – at

  13. Sediment load estimation in the Mellegue catchment, Algeria

    Directory of Open Access Journals (Sweden)

    Selmi Kaouther

    2016-12-01

    Full Text Available Soil erosion by water and the impact of sediment transport on lakes and streams, can seriously degrade soil and create problems for both agricultural land and water quality. The present study has been carried out to assess suspended sediment yield in Mellegue catchment, northeast of Algeria. Regression analysis was used to establish a relationship between the instantaneous water discharge (Q and the instantaneous suspended sediment concentration (C based on all recorded data and seasonal ratings for the period 1970–2003. The regression technique used in this paper involved a division of data into discharge – based classes, the mean concentrations and discharges of which are used to develop power regressions, according to single and season ratings, through log-transformation. Sediment loads estimated by stratified rating curves reduced underestimations to a range from 2 to 4%. The mean annual sediment yield during the 34 years of the study period was 589.23 t·km−2·y−1. Sediment transport is dominated by fall rainstorms accounting for 41% of the annual load. The big supply of sediment during this season confirms the intense geomorphic work by fall storms caused by high intensity rainfall and low vegetation cover.

  14. Absence of carbonic anhydrase on the surface of red cells suspended in an elutriator

    Energy Technology Data Exchange (ETDEWEB)

    Dodek, P.; Effros, R.M.

    1986-03-01

    Studies of the carbonic anhydrase activity of intact red cells are complicated by hemolysis, which markedly accelerates catalytic conversion between HCO/sub 2//sup -/ and CO/sub 2/. The authors have reduced this effect to negligible levels by studying red cells suspended with an elutriator. 1.Oml of packed rabbit red cells were introduced in an elutriator chamber which was spun in a centrifuge with a force of 2900G. An isotonic, pH 7.4, 6/sup 0/C, HCO/sub 3//sup -/ Ringer's lactate solution was pumped centripetally through the chamber to keep the cells in suspension. 0.1 ml of the perfusion solution containing /sup 22/Na/sup +/, /sup 36/Cl-, H/sup 14/CO/sub 3//sup -///sup 14/CO/sub 2/ (equilibrated), and /sup 3/H/sub 2/O were injected into the elutriator inflow and 22 samples were collected with a computerized anaerobic collector. Outflow concentrations of each radionuclide were divided by the amounts injected to yield fractional concentrations and upslope areas of indicators were divided by that of /sup 22/Na/sup +/ to yield an index of red cell exchange, R. Under control conditions, R(/sup 14/C) averaged .80 +/- .01 (S.E.). After anion exchange had been blocked with 0.1..mu..M DIDS, R(/sup 14/C) increased to .86 +/- .01. When 100 mg/1 bovine carbonic anhydrase was added R(/sup 1/$C) fell to .78 +/- .01. Subsequent addition of acetazolamide (10/sup -5/) increased R(/sup 14/C) to .86 +/- .01. R(/sup 36/Cl/sup -/) was increased from .91 +/- .02 to .96 +/- .01 after DIDS. These data indicate no detectable carbonic anhydrase activity on red cell surface.

  15. Filtration and clogging of permeable pavement loaded by urban drainage.

    Science.gov (United States)

    Sansalone, J; Kuang, X; Ying, G; Ranieri, V

    2012-12-15

    Permeable pavement, as a sustainable infrastructure material can promote hydrologic restoration, particulate matter (PM) and solute control. However, filtration and commensurate clogging are two aspects of continued interest and discussion. This study quantifies filtration and clogging of cementitious permeable pavement (CPP) for loadings from 50 to 200 mg/L of hetero-disperse sandy-silt PM. The CPP mix design provides a hetero-disperse pore size distribution (PSD)(pore), effective porosity (φ(e)) of 24% and median pore size of 658 μm with a standard deviation of 457 μm. The PM mass separation across the entire particle size distribution (PSD)(PM) exceeds 80%; with complete separation for PM greater than 300 μm and 50% separation for suspended PM. Turbidity is reduced (42-95%), and effluent is below 10 NTU in the first quartile of a loading period. Permeable pavement illustrates reductions in initial (clean-bed) hydraulic conductivity (k(0)) with loading time. For all PM loadings, k(0) (3.1 × 10(-1) mm/s) was reduced to 10(-4) mm/s for runoff loading durations from 100 to 250 h, respectively. Temporal hydraulic conductivity (k) follows exponential profiles. Maintenance by vacuuming and sonication illustrate that 96-99% of k(0) is recovered. Permeable pavement constitutive properties integrated with measured PM loads and a year of continuous rainfall-runoff simulation illustrate k reduction with historical loadings. Study results measure and model filtration and hydraulic conductivity phenomena as well as maintenance requirements of permeable pavement directly loaded by urban drainage. Copyright © 2011. Published by Elsevier Ltd.

  16. SEBARAN TOTAL SUSPENDED SOLID (TSS PADA PROFIL VERTIKAL DI PERAIRAN SELAT MADURA KABUPATEN BANGKALAN

    Directory of Open Access Journals (Sweden)

    Aries Dwi Siswanto

    2015-04-01

    Full Text Available Sebaran sedimen tersuspensi (Total Suspended Solid (TSS dapat dipelajari secara horizontal maupun vertikal. Akumulasi sedimen tersuspensi (TSS secara horizontal sangat dipengaruhi oleh arus permukaan maupun gelombang yang dibangkitkan oleh angin. Keterdapatan TSS ini diduga berpengaruh terhadap sebarannya pada profil vertical. Kedua kondisi sebaran sedimen tersuspensi (TSS berpengaruh terhadap optimalisasi penetrasi cahaya matahari di perairan. Sedimen tersuspensi (TSS menjadi salah satu factor fisika yang penting sebagai indicator kondisi perairan. Penelitian ini bertujuan untuk mengetahui sebaran Total Suspended Solid (TSS di perairan Kabupaten Bangkalan. Materi utama yang digunakan dalam penelitian ini adalah contoh air dan data parameter lingkungan (pasang surut dan kecerahan yang diambil pada 7 stasiun pada bulan Agustus-September 2013 di Perairan Selat Madura, Kabupaten Bangkalan. Metode gravimetric (SNI-06-6989.3-2004 digunakan untuk analisa Total Suspended Solid (TSS. Data parameter lingkungan dianalisa secara deskriptif. Analisa TSS menunjukkan nilai yang berbeda pada beberapa stasiun penelitian untuk setiap minggunya. Konsentrasi TSS terendah sebesar 35 mg/L (Stasiun 3, profil permukaan, minggu pertama dan tertinggi sebesar 620 mg/L (Stasiun 4, profil dasar, minggu pertama. Secara umum, konsentrasi TSS secara vertikal (dari permukaan-dasar cenderung semakin besar, diduga dipengaruhi oleh jenis substrat dan parameter arus yang berpeluang untuk menimbulkan pengadukan di profil dasar. Kondisi lingkungan (kecerahan dan arus menunjukkan bahwa daerah dengan konsentrasi TSS yang tinggi cenderung memilki nilai kecerahan yang rendah dengan kecepatan arus yang lebih besar.Kata Kunci: kecerahan, pola arus, Total Suspended Solid (TSS DISTRIBUTION OF TOTAL SUSPENDED SOLID (TSS IN THE VERTICAL PROFILE IN THE MADURA STRAIT WATERS BANGKALAN DISTRICTABSTRACTDistribution of suspended sediment (Total Suspended Solid (TSS can be studied through

  17. Mechanism isolates load weighing cell during lifting of load

    Science.gov (United States)

    Haigler, J. S.

    1966-01-01

    Load weighing cell used in conjuction with a hoist is isolated during lifting and manipulation of the load. A simple mechanism, attached to a crane hook, provides a screw adjustment for engaging the load cell during weighing of the load and isolating it from lift forces during hoisting of the load.

  18. Load flow analysis using decoupled fuzzy load flow under critical ...

    African Journals Online (AJOL)

    user

    The conventional load flow methods like Newton-Raphson load flow (NRLF), Fast Decoupled load flow (FDLF) provide poor performance under critical conditions such as high R/X ratio, heavily loading condition etc. Exploiting the decoupling properties of power system, reliable fuzzy load flow is developed to overcome the ...

  19. Tritium monitor and collection system

    Science.gov (United States)

    Bourne, Gary L.; Meikrantz, David H.; Ely, Walter E.; Tuggle, Dale G.; Grafwallner, Ervin G.; Wickham, Keith L.; Maltrud, Herman R.; Baker, John D.

    1992-01-01

    This system measures tritium on-line and collects tritium from a flowing inert gas stream. It separates the tritium from other non-hydrogen isotope contaminating gases, whether radioactive or not. The collecting portion of the system is constructed of various zirconium alloys called getters. These alloys adsorb tritium in any of its forms at one temperature and at a higher temperature release it as a gas. The system consists of four on-line getters and heaters, two ion chamber detectors, two collection getters, and two guard getters. When the incoming gas stream is valved through the on-line getters, 99.9% of it is adsorbed and the remainder continues to the guard getter where traces of tritium not collected earlier are adsorbed. The inert gas stream then exits the system to the decay chamber. Once the on-line getter has collected tritium for a predetermined time, it is valved off and the next on-line getter is valved on. Simultaneously, the first getter is heated and a pure helium purge is employed to carry the tritium from the getter. The tritium loaded gas stream is then routed through an ion chamber which measures the tritium activity. The ion chamber effluent passes through a collection getter that readsorbs the tritium and is removable from the system once it is loaded and is then replaced with a clean getter. Prior to removal of the collection getter, the system switches to a parallel collection getter. The effluent from the collection getter passes through a guard getter to remove traces of tritium prior to exiting the system. The tritium loaded collection getter, once removed, is analyzed by liquid scintillation techniques. The entire sequence is under computer control except for the removal and analysis of the collection getter.

  20. Concentrations, loads, and yields of select constituents from major tributaries of the Mississippi and Missouri Rivers in Iowa, water years 2004-2008

    Science.gov (United States)

    Garrett, Jessica D.

    2012-01-01

    Excess nutrients, suspended-sediment loads, and the presence of pesticides in Iowa rivers can have deleterious effects on water quality in State streams, downstream major rivers, and the Gulf of Mexico. Fertilizer and pesticides are used to support crop growth on Iowa's highly productive agricultural landscape and for household and commercial lawns and gardens. Water quality was characterized near the mouths of 10 major Iowa tributaries to the Mississippi and Missouri Rivers from March 2004 through September 2008. Stream loads were calculated for select ions, nutrients, and sediment using approximately monthly samples, and samples from storm and snowmelt events. Water-quality samples collected using standard streamflow-integrated protocols were analyzed for major ions, nutrients, carbon, pesticides, and suspended sediment. Statistical data summaries of sample data used parametric and nonparametric techniques to address potential bias related to censored data and multiple levels of censoring of data below analytical detection limits. Constituent stream loads were computed using standard pre-defined models in S-LOADEST that include streamflow and time terms plus additional terms for streamflow variability and streamflow anomalies. Streamflow variability terms describe the difference in streamflow from recent average conditions, whereas streamflow anomaly terms account for deviations from average conditions from long- to short-term sequentially. Streamflow variability or anomaly terms were included in 44 of 80 site/constituent individual models, demonstrating the usefulness of these terms in increasing accuracy of the load estimates. Constituent concentrations in Iowa streams exhibit streamflow, seasonal, and spatial patterns related to the landform and climate gradients across the studied basins. The streamflow-concentration relation indicated dilution for ions such as chloride and sulfate. Other constituent concentrations, such as dissolved organic carbon and