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Sample records for stream flow time

  1. A Statistical Method to Predict Flow Permanence in Dryland Streams from Time Series of Stream Temperature

    Directory of Open Access Journals (Sweden)

    Ivan Arismendi

    2017-12-01

    Full Text Available Intermittent and ephemeral streams represent more than half of the length of the global river network. Dryland freshwater ecosystems are especially vulnerable to changes in human-related water uses as well as shifts in terrestrial climates. Yet, the description and quantification of patterns of flow permanence in these systems is challenging mostly due to difficulties in instrumentation. Here, we took advantage of existing stream temperature datasets in dryland streams in the northwest Great Basin desert, USA, to extract critical information on climate-sensitive patterns of flow permanence. We used a signal detection technique, Hidden Markov Models (HMMs, to extract information from daily time series of stream temperature to diagnose patterns of stream drying. Specifically, we applied HMMs to time series of daily standard deviation (SD of stream temperature (i.e., dry stream channels typically display highly variable daily temperature records compared to wet stream channels between April and August (2015–2016. We used information from paired stream and air temperature data loggers as well as co-located stream temperature data loggers with electrical resistors as confirmatory sources of the timing of stream drying. We expanded our approach to an entire stream network to illustrate the utility of the method to detect patterns of flow permanence over a broader spatial extent. We successfully identified and separated signals characteristic of wet and dry stream conditions and their shifts over time. Most of our study sites within the entire stream network exhibited a single state over the entire season (80%, but a portion of them showed one or more shifts among states (17%. We provide recommendations to use this approach based on a series of simple steps. Our findings illustrate a successful method that can be used to rigorously quantify flow permanence regimes in streams using existing records of stream temperature.

  2. A statistical method to predict flow permanence in dryland streams from time series of stream temperature

    Science.gov (United States)

    Arismendi, Ivan; Dunham, Jason B.; Heck, Michael; Schultz, Luke; Hockman-Wert, David

    2017-01-01

    Intermittent and ephemeral streams represent more than half of the length of the global river network. Dryland freshwater ecosystems are especially vulnerable to changes in human-related water uses as well as shifts in terrestrial climates. Yet, the description and quantification of patterns of flow permanence in these systems is challenging mostly due to difficulties in instrumentation. Here, we took advantage of existing stream temperature datasets in dryland streams in the northwest Great Basin desert, USA, to extract critical information on climate-sensitive patterns of flow permanence. We used a signal detection technique, Hidden Markov Models (HMMs), to extract information from daily time series of stream temperature to diagnose patterns of stream drying. Specifically, we applied HMMs to time series of daily standard deviation (SD) of stream temperature (i.e., dry stream channels typically display highly variable daily temperature records compared to wet stream channels) between April and August (2015–2016). We used information from paired stream and air temperature data loggers as well as co-located stream temperature data loggers with electrical resistors as confirmatory sources of the timing of stream drying. We expanded our approach to an entire stream network to illustrate the utility of the method to detect patterns of flow permanence over a broader spatial extent. We successfully identified and separated signals characteristic of wet and dry stream conditions and their shifts over time. Most of our study sites within the entire stream network exhibited a single state over the entire season (80%), but a portion of them showed one or more shifts among states (17%). We provide recommendations to use this approach based on a series of simple steps. Our findings illustrate a successful method that can be used to rigorously quantify flow permanence regimes in streams using existing records of stream temperature.

  3. Size-selective sorting in bubble streaming flows: Particle migration on fast time scales

    Science.gov (United States)

    Thameem, Raqeeb; Rallabandi, Bhargav; Hilgenfeldt, Sascha

    2015-11-01

    Steady streaming from ultrasonically driven microbubbles is an increasingly popular technique in microfluidics because such devices are easily manufactured and generate powerful and highly controllable flows. Combining streaming and Poiseuille transport flows allows for passive size-sensitive sorting at particle sizes and selectivities much smaller than the bubble radius. The crucial particle deflection and separation takes place over very small times (milliseconds) and length scales (20-30 microns) and can be rationalized using a simplified geometric mechanism. A quantitative theoretical description is achieved through the application of recent results on three-dimensional streaming flow field contributions. To develop a more fundamental understanding of the particle dynamics, we use high-speed photography of trajectories in polydisperse particle suspensions, recording the particle motion on the time scale of the bubble oscillation. Our data reveal the dependence of particle displacement on driving phase, particle size, oscillatory flow speed, and streaming speed. With this information, the effective repulsive force exerted by the bubble on the particle can be quantified, showing for the first time how fast, selective particle migration is effected in a streaming flow. We acknowledge support by the National Science Foundation under grant number CBET-1236141.

  4. Type and timing of stream flow changes in urbanizing watersheds in the Eastern U.S.

    Directory of Open Access Journals (Sweden)

    Kristina G. Hopkins

    2015-06-01

    Full Text Available Abstract Linking the type and timing of hydrologic changes with patterns of urban growth is essential to identifying the underlying mechanisms that drive declines in urban aquatic ecosystems. In six urbanizing watersheds surrounding three U.S. cities (Baltimore, MD, Boston, MA, and Pittsburgh, PA, we reconstructed the history of development patterns since 1900 and assessed the magnitude and timing of stream flow changes during watershed development. Development reconstructions indicated that the majority of watershed development occurred during a period of peak population growth, typically between 1950 and 1970. Stream flow records indicated significant increases in annual frequency of high-flow events in all six watersheds and increases in annual runoff efficiency in five watersheds. Annual development intensity during the peak growth period had the strongest association with the magnitude of changes in high-flow frequency from the pre- to post-development periods. Results suggest the timing of the peak growth period is particularly important to understanding hydrologic changes, because it can set the type of stormwater infrastructure installed within a watershed. In three watersheds there was a rapid (∼10-15 years shift toward more frequent high-flow events, and in four watersheds there was a shift toward higher runoff efficiency. Breakpoint analyses indicated these shifts occurred between 1969 and 1976 for high-flow frequency and between 1962 and 1984 for runoff efficiency. Results indicated that the timing of high-flow changes were mainly driven by the development trajectory of each watershed, whereas the timing of runoff-efficiency changes were driven by a combination of development trajectories and extreme weather events. Our results underscore the need to refine the causes of urban stream degradation to incorporate the impact of gradual versus rapid urbanization on hydrologic changes and aquatic ecosystem function, as well as to

  5. Impact of meander geometry and stream flow events on residence times and solute transport in the intra-meander flow

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    Nasir Mahmood, Muhammad; Schmidt, Christian; Trauth, Nico

    2017-04-01

    Stream morphological features, in combination with hydrological variability play a key role in water and solute exchange across surface and subsurface waters. Meanders are prominent morphological features within stream systems which exhibit unique hydrodynamics. The water surface elevation difference across the inner bank of a meander induces lateral hyporheic exchange within the intra-meander region. This hyporheic flow is characterized by considerably prolonged flow paths and residence times (RT) compared to smaller scales of hyporheic exchange. In this study we examine the impact of different meander geometries on the intra-meander hyporheic flow field and solute mobilization under both steady state and transient flow conditions. We developed a number of artificial meander shape scenarios, representing various meander evolution stages, ranging from a typical initial to advanced stage (near cut off ) meander. Three dimensional steady state numerical groundwater flow simulations including the unsaturated zone were performed for the intra-meander region. The meandering stream was implemented in the model by adjusting the top layers of the modelling domain to the streambed elevation and assigning linearly decreasing head boundary conditions to the streambed cells. Residence times for the intra-meander region were computed by advective particle tracking across the inner bank of meander. Selected steady state cases were extended to transient flow simulations to evaluate the impact of stream discharge events on the temporal behavior of the water exchange and solute transport in the intra-meander region. The transient stream discharge was simulated for a number of discharge events of variable duration and peak height using the surface water model HEC-RAS. Transient hydraulic heads obtained from the surface water model were applied as transient head boundary conditions to the streambed cells of the groundwater model. A solute concentration source was added in the

  6. Application of Genetic Programing to Develop a Modular Model for the Simulation of Stream Flow Time Series

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    Meshgi, A.; Babovic, V.; Chui, T. F. M.; Schmitter, P.

    2014-12-01

    Developing reliable methods to estimate stream flow has been a subject of interest due to its importance in planning, design and management of water resources within a basin. Machine learning tools such as Artificial Neural Network (ANN) and Genetic Programming (GP) have been widely applied for rainfall-runoff modeling as they require less computational time as compared to physically-based models. As GP is able to generate a function with understandable structure, it may offer advantages over other data driven techniques and therefore has been used in different studies to generate rainfall-runoff functions. However, to date, proposed formulations only contain rainfall and/or streamflow data and consequently are local and cannot be generalized and adopted in other catchments which have different physical characteristics. This study investigated the capability of GP in developing a physically interpretable model with understandable structure to simulate stream flow based on hydrological parameters (e.g. precipitation) and catchment conditions (e.g., initial groundwater table elevation and area of the catchment) by following a modular approach. The modular model resulted in two sub-models where the baseflow was first predicted and the direct runoff was then estimated for a semi-urban catchment in Singapore. The simulated results matched very well with observed data in both the training and the testing of data sets, giving NSEs of 0.97 and 0.96 respectively demonstrated the successful estimation of stream flow using the modular model derived in this study. The results of this study indicate that GP is an effective tool in developing a physically interpretable model with understandable structure to simulate stream flow that can be transferred to other catchments.

  7. Modelling mean transit time of stream base flow during tropical cyclone rainstorm in a steep relief forested catchment

    Science.gov (United States)

    Lee, Jun-Yi; Huang, -Chuan, Jr.

    2017-04-01

    Mean transit time (MTT) is one of the of fundamental catchment descriptors to advance understanding on hydrological, ecological, and biogeochemical processes and improve water resources management. However, there were few documented the base flow partitioning (BFP) and mean transit time within a mountainous catchment in typhoon alley. We used a unique data set of 18O isotope and conductivity composition of rainfall (136 mm to 778 mm) and streamflow water samples collected for 14 tropical cyclone events (during 2011 to 2015) in a steep relief forested catchment (Pinglin, in northern Taiwan). A lumped hydrological model, HBV, considering dispersion model transit time distribution was used to estimate total flow, base flow, and MTT of stream base flow. Linear regression between MTT and hydrometric (precipitation intensity and antecedent precipitation index) variables were used to explore controls on MTT variation. Results revealed that both the simulation performance of total flow and base flow were satisfactory, and the Nash-Sutcliffe model efficiency coefficient of total flow and base flow was 0.848 and 0.732, respectively. The event magnitude increased with the decrease of estimated MTTs. Meanwhile, the estimated MTTs varied 4-21 days with the increase of BFP between 63-92%. The negative correlation between event magnitude and MTT and BFP showed the forcing controls the MTT and BFP. Besides, a negative relationship between MTT and the antecedent precipitation index was also found. In other words, wetter antecedent moisture content more rapidly active the fast flow paths. This approach is well suited for constraining process-based modeling in a range of high precipitation intensity and steep relief forested environments.

  8. Investigation of Relationship Between Hydrologic Processes of Precipitation, Evaporation and Stream Flow Using Linear Time Series Models (Case study: Western Basins of Lake Urmia

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    M. Moravej

    2016-02-01

    Full Text Available Introduction: Studying the hydrological cycle, especially in large scales such as water catchments, is difficult and complicated despite the fact that the numbers of hydrological components are limited. This complexity rises from complex interactions between hydrological components and environment. Recognition, determination and modeling of all interactive processes are needed to address this issue, but it's not feasible for dealing with practical engineering problems. So, it is more convenient to consider hydrological components as stochastic phenomenon, and use stochastic models for modeling them. Stochastic simulation of time series models related to water resources, particularly hydrologic time series, have been widely used in recent decades in order to solve issues pertaining planning and management of water resource systems. In this study time series models fitted to the precipitation, evaporation and stream flow series separately and the relationships between stream flow and precipitation processes are investigated. In fact, the three mentioned processes should be modeled in parallel to each other in order to acquire a comprehensive vision of hydrological conditions in the region. Moreover, the relationship between the hydrologic processes has been mostly studied with respect to their trends. It is desirable to investigate the relationship between trends of hydrological processes and climate change, while the relationship of the models has not been taken into consideration. The main objective of this study is to investigate the relationship between hydrological processes and their effects on each other and the selected models. Material and Method: In the current study, the four sub-basins of Lake Urmia Basin namely Zolachay (A, Nazloochay (B, Shahrchay (C and Barandoozchay (D were considered. Precipitation, evaporation and stream flow time series were modeled by linear time series. Fundamental assumptions of time series analysis namely

  9. Three-dimensional microbubble streaming flows

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    Rallabandi, Bhargav; Marin, Alvaro; Rossi, Massimiliano; Kaehler, Christian; Hilgenfeldt, Sascha

    2014-11-01

    Streaming due to acoustically excited bubbles has been used successfully for applications such as size-sorting, trapping and focusing of particles, as well as fluid mixing. Many of these applications involve the precise control of particle trajectories, typically achieved using cylindrical bubbles, which establish planar flows. Using astigmatic particle tracking velocimetry (APTV), we show that, while this two-dimensional picture is a useful description of the flow over short times, a systematic three-dimensional flow structure is evident over long time scales. We demonstrate that this long-time three-dimensional fluid motion can be understood through asymptotic theory, superimposing secondary axial flows (induced by boundary conditions at the device walls) onto the two-dimensional description. This leads to a general framework that describes three-dimensional flows in confined microstreaming systems, guiding the design of applications that profit from minimizing or maximizing these effects.

  10. 7Q10 flows for SRS streams

    International Nuclear Information System (INIS)

    Chen, K.F.

    1996-01-01

    The Environmental Transport Group of the Environmental Technology Section was requested to predict the seven-day ten-year low flow (7Q10 flow) for the SRS streams based on historical stream flow records. Most of the historical flow records for the SRS streams include reactor coolant water discharged from the reactors and process water released from the process facilities. The most straight forward way to estimate the stream daily natural flow is to subtract the measured upstream reactor and/or facility daily effluents from the measured downstream daily flow. Unfortunately, this method does not always work, as indicated by the fact that sometimes the measured downstream volumetric flow rates are lower than the reactor effluent volumetric flow rates. For those cases that cannot be analyzed with the simple subtracting method, an alternative method was used to estimate the stream natural flows by statistically separating reactor coolant and process water flow data. The correlation between the calculated 7Q10 flows and the watershed areas for Four Mile Branch and Pen Branch agrees with that calculated by the USGS for Upper Three Runs and Lower Three Runs Creeks. The agreement between these two independent calculations lends confidence to the 7Q10 flow calculations presented in this report

  11. Ambient groundwater flow diminishes nitrogen cycling in streams

    Science.gov (United States)

    Azizian, M.; Grant, S. B.; Rippy, M.; Detwiler, R. L.; Boano, F.; Cook, P. L. M.

    2017-12-01

    Modeling and experimental studies demonstrate that ambient groundwater reduces hyporheic exchange, but the implications of this observation for stream N-cycling is not yet clear. We utilized a simple process-based model (the Pumping and Streamline Segregation or PASS model) to evaluate N- cycling over two scales of hyporheic exchange (fluvial ripples and riffle-pool sequences), ten ambient groundwater and stream flow scenarios (five gaining and losing conditions and two stream discharges), and three biogeochemical settings (identified based on a principal component analysis of previously published measurements in streams throughout the United States). Model-data comparisons indicate that our model provides realistic estimates for direct denitrification of stream nitrate, but overpredicts nitrification and coupled nitrification-denitrification. Riffle-pool sequences are responsible for most of the N-processing, despite the fact that fluvial ripples generate 3-11 times more hyporheic exchange flux. Across all scenarios, hyporheic exchange flux and the Damkohler Number emerge as primary controls on stream N-cycling; the former regulates trafficking of nutrients and oxygen across the sediment-water interface, while the latter quantifies the relative rates of organic carbon mineralization and advective transport in streambed sediments. Vertical groundwater flux modulates both of these master variables in ways that tend to diminish stream N-cycling. Thus, anthropogenic perturbations of ambient groundwater flows (e.g., by urbanization, agricultural activities, groundwater mining, and/or climate change) may compromise some of the key ecosystem services provided by streams.

  12. Optimized open-flow mixing: insights from microbubble streaming

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    Rallabandi, Bhargav; Wang, Cheng; Guo, Lin; Hilgenfeldt, Sascha

    2015-11-01

    Microbubble streaming has been developed into a robust and powerful flow actuation technique in microfluidics. Here, we study it as a paradigmatic system for microfluidic mixing under a continuous throughput of fluid (open-flow mixing), providing a systematic optimization of the device parameters in this practically important situation. Focusing on two-dimensional advective stirring (neglecting diffusion), we show through numerical simulation and analytical theory that mixing in steady streaming vortices becomes ineffective beyond a characteristic time scale, necessitating the introduction of unsteadiness. By duty cycling the streaming, such unsteadiness is introduced in a controlled fashion, leading to exponential refinement of the advection structures. The rate of refinement is then optimized for particular parameters of the time modulation, i.e. a particular combination of times for which the streaming is turned ``on'' and ``off''. The optimized protocol can be understood theoretically using the properties of the streaming vortices and the throughput Poiseuille flow. We can thus infer simple design principles for practical open flow micromixing applications, consistent with experiments. Current Address: Mechanical and Aerospace Engineering, Princeton University.

  13. Stream Tracker: Crowd sourcing and remote sensing to monitor stream flow intermittence

    Science.gov (United States)

    Puntenney, K.; Kampf, S. K.; Newman, G.; Lefsky, M. A.; Weber, R.; Gerlich, J.

    2017-12-01

    Streams that do not flow continuously in time and space support diverse aquatic life and can be critical contributors to downstream water supply. However, these intermittent streams are rarely monitored and poorly mapped. Stream Tracker is a community powered stream monitoring project that pairs citizen contributed observations of streamflow presence or absence with a network of streamflow sensors and remotely sensed data from satellites to track when and where water is flowing in intermittent stream channels. Citizens can visit sites on roads and trails to track flow and contribute their observations to the project site hosted by CitSci.org. Data can be entered using either a mobile application with offline capabilities or an online data entry portal. The sensor network provides a consistent record of streamflow and flow presence/absence across a range of elevations and drainage areas. Capacitance, resistance, and laser sensors have been deployed to determine the most reliable, low cost sensor that could be mass distributed to track streamflow intermittence over a larger number of sites. Streamflow presence or absence observations from the citizen and sensor networks are then compared to satellite imagery to improve flow detection algorithms using remotely sensed data from Landsat. In the first two months of this project, 1,287 observations have been made at 241 sites by 24 project members across northern and western Colorado.

  14. Low-flow characteristics of Virginia streams

    Science.gov (United States)

    Austin, Samuel H.; Krstolic, Jennifer L.; Wiegand, Ute

    2011-01-01

    Low-flow annual non-exceedance probabilities (ANEP), called probability-percent chance (P-percent chance) flow estimates, regional regression equations, and transfer methods are provided describing the low-flow characteristics of Virginia streams. Statistical methods are used to evaluate streamflow data. Analysis of Virginia streamflow data collected from 1895 through 2007 is summarized. Methods are provided for estimating low-flow characteristics of gaged and ungaged streams. The 1-, 4-, 7-, and 30-day average streamgaging station low-flow characteristics for 290 long-term, continuous-record, streamgaging stations are determined, adjusted for instances of zero flow using a conditional probability adjustment method, and presented for non-exceedance probabilities of 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, 0.02, 0.01, and 0.005. Stream basin characteristics computed using spatial data and a geographic information system are used as explanatory variables in regional regression equations to estimate annual non-exceedance probabilities at gaged and ungaged sites and are summarized for 290 long-term, continuous-record streamgaging stations, 136 short-term, continuous-record streamgaging stations, and 613 partial-record streamgaging stations. Regional regression equations for six physiographic regions use basin characteristics to estimate 1-, 4-, 7-, and 30-day average low-flow annual non-exceedance probabilities at gaged and ungaged sites. Weighted low-flow values that combine computed streamgaging station low-flow characteristics and annual non-exceedance probabilities from regional regression equations provide improved low-flow estimates. Regression equations developed using the Maintenance of Variance with Extension (MOVE.1) method describe the line of organic correlation (LOC) with an appropriate index site for low-flow characteristics at 136 short-term, continuous-record streamgaging stations and 613 partial-record streamgaging stations. Monthly

  15. Time-Based Data Streams: Fundamental Concepts for a Data Resource for Streams

    Energy Technology Data Exchange (ETDEWEB)

    Beth A. Plale

    2009-10-10

    Real time data, which we call data streams, are readings from instruments, environmental, bodily or building sensors that are generated at regular intervals and often, due to their volume, need to be processed in real time. Often a single pass is all that can be made on the data, and a decision to discard or keep the instance is made on the spot. Too, the stream is for all practical purposes indefinite, so decisions must be made on incomplete knowledge. This notion of data streams has a different set of issues from a file, for instance, that is byte streamed to a reader. The file is finite, so the byte stream is becomes a processing convenience more than a fundamentally different kind of data. Through the duration of the project we examined three aspects of streaming data: the first, techniques to handle streaming data in a distributed system organized as a collection of web services, the second, the notion of the dashboard and real time controllable analysis constructs in the context of the Fermi Tevatron Beam Position Monitor, and third and finally, we examined provenance collection of stream processing such as might occur as raw observational data flows from the source and undergoes correction, cleaning, and quality control. The impact of this work is severalfold. We were one of the first to advocate that streams had little value unless aggregated, and that notion is now gaining general acceptance. We were one of the first groups to grapple with the notion of provenance of stream data also.

  16. Shock formation and structure in magnetic reconnection with a streaming flow.

    Science.gov (United States)

    Wu, Liangneng; Ma, Zhiwei; Zhang, Haowei

    2017-08-18

    The features of magnetic reconnection with a streaming flow have been investigated on the basis of compressible resistive magnetohydrodynamic (MHD) model. The super-Alfvenic streaming flow largely enhances magnetic reconnection. The maximum reconnection rate is almost four times larger with super-Alfvenic streaming flow than sub-Alfvénic streaming flow. In the nonlinear stage, it is found that there is a pair of shocks observed in the inflow region, which are manifested to be slow shocks for sub-Alfvénic streaming flow, and fast shocks for super-Alfvénic streaming flow. The quasi-period oscillation of reconnection rates in the decaying phase for super-Alfvénic streaming flow is resulted from the different drifting velocities of the shock and the X point.

  17. Quantifying the role of vegetation in controlling the time-variant age of evapotranspiration, soil water and stream flow

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    Smith, A.; Tetzlaff, D.; Soulsby, C.

    2017-12-01

    Identifying the sources of water which sustain plant water uptake is an essential prerequisite to understanding the interactions of vegetation and water within the critical zone. Estimating the sources of root-water uptake is complicated by ecohydrological separation, or the notion of "two-water worlds" which distinguishes more mobile and immobile water sources which respectively sustain streamflow and evapotranspiration. Water mobility within the soil determines both the transit time/residence time of water through/in soils and the subsequent age of root-uptake and xylem water. We used time-variant StorAge Selection (SAS) functions to conceptualise the transit/residence times in the critical zone using a dual-storage soil column differentiating gravity (mobile) and tension dependent (immobile) water, calibrated to measured stable isotope signatures of soil water. Storage-discharge relationships [Brutsaert and Nieber, 1977] were used to identify gravity and tension dependent storages. A temporally variable distribution for root water uptake was identified using simulated stable isotopes in xylem and soil water. Composition of δ2H and δ18O was measured in soil water at 4 depths (5, 10, 15, and 20 cm) on 10 occasions, and 5 times for xylem water within the dominant heather (Calluna sp. and Erica sp.) vegetation in a Scottish Highland catchment over a two-year period. Within a 50 cm soil column, we found that more than 53% of the total stored water was water that was present before the start of the simulation. Mean residence times of the mobile water in the upper 20 cm of the soil were 16, 25, 36, and 44 days, respectively. Mean evaporation transit time varied between 9 and 40 days, driven by seasonal changes and precipitation events. Lastly, mean transit times of xylem water ranged between 95-205 days, driven by changes in soil moisture. During low soil moisture (i.e. lower than mean soil moisture), root-uptake was from lower depths, while higher than mean soil

  18. Flow of a stream through a reservoir

    International Nuclear Information System (INIS)

    Sauerwein, K.

    1967-01-01

    If a reservoir is fed from a single source, which may not always be pure, the extent to which the inflowing stream mixes with the water in the reservoir is important for the quality of the water supplied by the reservoir. This question was investigated at the Lingese Reservoir, containing between one and two million cubic metres of water, in the Bergisches Land (North Rhine-Westphalia). The investigation was carried out at four different seasons so that the varying effects of the stream-water temperatures could be studied in relation to the temperature of the reservoir water. The stream was radioactively labelled at the point of inflow into the reservoir, and its flow through the reservoir was measured in length and depth from boats, by means of 1-m-long Geiger counters. In two cases the radioactivity of the outflowing water was also measured at fixed points. A considerable variety of intermixing phenomena were observed; these were mainly of limnological interest. The results of four experiments corresponding to the four different seasons are described in detail. They were as follows: (1) The mid-October experiment where the stream, with a temperature of 8.0 deg. C, was a good 5 deg. C colder than the water of the reservoir, whose temperature was almost uniform, ranging from 13.2 deg. C at the bed to 13.6 deg. C at the surface. (2) The spring experiment (second half of March), when the stream temperature was only 0.3 deg. C below that of the reservoir surface (7.8 deg. C), while the temperature of the bed was 5.8 deg. C. (3) The winter experiment (early December) where at first the temperature of the stream was approximately the same as that of the surface so that, once again, the stream at first flowed 1/2 - 1 m below the surface. During the almost wind-free night a sudden fall in temperature occurred, and the air temperature dropped from 0 deg. C to -12 deg. C. (4) The summer experiment (end of July to mid-August) when the stream was nearly 1 deg. C colder than

  19. The long term response of stream flow to climatic warming in headwater streams of interior Alaska

    Science.gov (United States)

    Jeremy B. Jones; Amanda J. Rinehart

    2010-01-01

    Warming in the boreal forest of interior Alaska will have fundamental impacts on stream ecosystems through changes in stream hydrology resulting from upslope loss of permafrost, alteration of availability of soil moisture, and the distribution of vegetation. We examined stream flow in three headwater streams of the Caribou-Poker Creeks Research Watershed (CPCRW) in...

  20. Flow effects on benthic stream invertebrates and ecological processes

    Science.gov (United States)

    Koprivsek, Maja; Brilly, Mitja

    2010-05-01

    Flow is the main abiotic factor in the streams. Flow affects the organisms in many direct and indirect ways. The organisms are directly affected by various hydrodynamic forces and mass transfer processes like drag forces, drift, shear stress, food and gases supply and washing metabolites away. Indirect effects on the organisms are determining and distribution of the particle size and structure of the substrate and determining the morphology of riverbeds. Flow does not affect only on individual organism, but also on many ecological effects. To expose just the most important: dispersal of the organisms, habitat use, resource acquisition, competition and predator-prey interactions. Stream invertebrates are adapted to the various flow conditions in many kinds of way. Some of them are avoiding the high flow with living in a hyporeic zone, while the others are adapted to flow with physical adaptations (the way of feeding, respiration, osmoregulation and resistance to draught), morphological adaptations (dorsoventrally flattened shape of organism, streamlined shape of organism, heterogeneous suckers, silk, claws, swimming hair, bristles and ballast gravel) or with behaviour. As the flow characteristics in a particular stream vary over a broad range of space and time scales, it is necessary to measure accurately the velocity in places where the organisms are present to determine the actual impact of flow on aquatic organisms. By measuring the mean flow at individual vertical in a single cross-section, we cannot get any information about the velocity situation close to the bottom of the riverbed where the stream invertebrates are living. Just measuring the velocity near the bottom is a major problem, as technologies for measuring the velocity and flow of natural watercourses is not adapted to measure so close to the bottom. New researches in the last two decades has shown that the thickness of laminar border layer of stones in the stream is only a few 100 micrometers, what

  1. Frequency dependence and frequency control of microbubble streaming flows

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    Wang, Cheng; Rallabandi, Bhargav; Hilgenfeldt, Sascha

    2013-02-01

    Steady streaming from oscillating microbubbles is a powerful actuating mechanism in microfluidics, enjoying increased use due to its simplicity of manufacture, ease of integration, low heat generation, and unprecedented control over the flow field and particle transport. As the streaming flow patterns are caused by oscillations of microbubbles in contact with walls of the set-up, an understanding of the bubble dynamics is crucial. Here we experimentally characterize the oscillation modes and the frequency response spectrum of such cylindrical bubbles, driven by a pressure variation resulting from ultrasound in the range of 1 kHz raisebox {-.9ex{stackrel{textstyle <}{˜ }} }f raisebox {-.9ex{stackrel{textstyle <}{˜ }} } 100 kHz. We find that (i) the appearance of 2D streaming flow patterns is governed by the relative amplitudes of bubble azimuthal surface modes (normalized by the volume response), (ii) distinct, robust resonance patterns occur independent of details of the set-up, and (iii) the position and width of the resonance peaks can be understood using an asymptotic theory approach. This theory describes, for the first time, the shape oscillations of a pinned cylindrical bubble at a wall and gives insight into necessary mode couplings that shape the response spectrum. Having thus correlated relative mode strengths and observed flow patterns, we demonstrate that the performance of a bubble micromixer can be optimized by making use of such flow variations when modulating the driving frequency.

  2. Stochastic Modelling of Shiroro River Stream flow Process

    OpenAIRE

    Musa, J. J

    2013-01-01

    Economists, social scientists and engineers provide insights into the drivers of anthropogenic climate change and the options for adaptation and mitigation, and yet other scientists, including geographers and biologists, study the impacts of climate change. This project concentrates mainly on the discharge from the Shiroro River. A stochastic approach is presented for modeling a time series by an Autoregressive Moving Average model (ARMA). The development and use of a stochastic stream flow m...

  3. High levels of endocrine pollutants in US streams during low flow due to insufficient wastewater dilution

    Science.gov (United States)

    Rice, Jacelyn; Westerhoff, Paul

    2017-08-01

    Wastewater discharges from publicly owned treatment works are a significant source of endocrine disruptors and other contaminants to the aquatic environment in the US. Although remaining pollutants in wastewater pose environmental risks, treated wastewater is also a primary source of stream flow, which in turn is critical in maintaining many aquatic and riparian wildlife habitats. Here we calculate the dilution factor--the ratio of flow in the stream receiving discharge to the flow of wastewater discharge--for over 14,000 receiving streams in the continental US using streamflow observations and a spatially explicit watershed-scale hydraulic model. We found that wastewater discharges make up more than 50% of in-stream flow for over 900 streams. However, in 1,049 streams that experienced exceptional low-flow conditions, the dilution factors in 635 of those streams fell so low during those conditions that the safety threshold for concentrations of one endocrine disrupting compound was exceeded, and in roughly a third of those streams, the threshold was exceeded for two compounds. We suggest that streams are vulnerable to public wastewater discharge of contaminants under low-flow conditions, at a time when wastewater discharges are likely to be most important for maintaining stream flow for smaller sized river systems.

  4. Stream Intermittency Sensors Monitor the Onset and Duration of Stream Flow Along a Channel Network During Storms

    Science.gov (United States)

    Jensen, C.; McGuire, K. J.

    2017-12-01

    Headwater streams are spatially extensive, accounting for a majority of global stream length, and supply downstream water bodies with water, sediment, organic matter, and pollutants. Much of this transmission occurs episodically during storms when stream flow and connectivity are high. Many headwaters are temporary streams that expand and contract in length in response to storms and seasonality. Understanding where and when streams carry flow is critical for conserving headwaters and protecting downstream water quality, but storm events are difficult to study in small catchments. The rise and fall of stream flow occurs rapidly in headwaters, making observation of the entire stream network difficult. Stream intermittency sensors that detect the presence or absence of water can reveal wetting and drying patterns over short time scales. We installed 50 intermittency sensors along the channel network of a small catchment (35 ha) in the Valley and Ridge of southwest Virginia. Previous work shows stream length is highly variable in this shale catchment, as the drainage density spans two orders of magnitude. The sensors record data every 15 minutes for one year to capture different seasons, antecedent moisture conditions, and precipitation rates. We seek to determine whether hysteresis between stream flow and network length occurs on the rising and falling limbs of events and if reach-scale characteristics such as valley width explain spatial patterns of flow duration. Our results indicate reaches with a wide, sediment-filled valley floor carry water for shorter periods of time than confined channel segments with steep valley side slopes. During earlier field mapping surveys, we only observed flow in a few of the tributaries for the wettest conditions mapped. The sensors now show that these tributaries flow more frequently during much smaller storms, but only for brief periods of time (hour). The high temporal sampling resolution of the sensors permits a more realistic

  5. A spatial assessment of stream-flow characteristics and hydrologic ...

    African Journals Online (AJOL)

    The global hydrologic regime has been intensively altered through activities such as dam construction, water abstraction, and inter-basin transfers. This paper uses the Range of Variability Approach (RVA) and daily stream flow records from nine gauging stations to characterize stream-flow post dam construction in the ...

  6. Visualization investigation of acoustic and flow-induced vibration in main stream lines using a high-time-resolved PIV technique

    International Nuclear Information System (INIS)

    Li, Yanrong; Someya, Satoshi; Okamoto, Koji

    2009-01-01

    Systems with closed side-branches are liable to an excitation of sound, as called cavity tone. It may occur in pipe branches leading to safety valves or to boiler relief valves. The outbreak mechanism of the cavity tone has been known by phase-averaged measurement in previous researches, while the relation between sound propagation and flow field is still unclear due to the difficulty of detecting instantaneous velocity field. High-time-resolved PIV has a possibility to analyze the velocity field and the relation mentioned above. In this study, flow-induced acoustic resonance of piping system containing closed side-branches was investigated experimentally. A high-time-resolved PIV technique was applied to measure a gas-flow in a cavity. Air flow containing oil mist as tracer particles was measured using a high frequency pulse laser and a high speed camera. The present investigation on the coaxial closed side-branches is the first rudimentary study to visualize the fluid flow two-dimensionally in the cross-section by using PIV and to measure the pressure at the downstream side opening of the cavity by microphone. The fluid flows at different points in the cavity interact with some phase differences and the relation was clarified. (author)

  7. Hydroelectric plant turbine, stream and spillway flow measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lampa, J.; Lemon, D.; Buermans, J. [ASL AQ Flow Inc., Sidney, BC (Canada)

    2004-07-01

    This presentation provided schematics of the turbine flow measurements and typical bulb installations at the Kootenay Canal and Wells hydroelectric power facilities in British Columbia. A typical arrangement for measuring stream flow using acoustic scintillation was also illustrated. Acoustic scintillation is portable, non-intrusive, suitable for short intakes, requires minimal maintenance and is cost effective and accurate. A comparison between current meters and acoustic scintillation was also presented. Stream flow measurement is valuable in evaluating downstream areas that are environmentally important for fish habitat. Stream flow measurement makes it possible to define circulation. The effects of any changes can be assessed by combining field measurements and numerical modelling. The presentation also demonstrated that computational fluid dynamics modelling appears promising in determining stream flow and turbulent flow at spillways. tabs., figs.

  8. Short-term stream flow forecasting at Australian river sites using data-driven regression techniques

    CSIR Research Space (South Africa)

    Steyn, Melise

    2017-09-01

    Full Text Available This study proposes a computationally efficient solution to stream flow forecasting for river basins where historical time series data are available. Two data-driven modeling techniques are investigated, namely support vector regression...

  9. Flow-covariate prediction of stream pesticide concentrations.

    Science.gov (United States)

    Mosquin, Paul L; Aldworth, Jeremy; Chen, Wenlin

    2018-01-01

    Potential peak functions (e.g., maximum rolling averages over a given duration) of annual pesticide concentrations in the aquatic environment are important exposure parameters (or target quantities) for ecological risk assessments. These target quantities require accurate concentration estimates on nonsampled days in a monitoring program. We examined stream flow as a covariate via universal kriging to improve predictions of maximum m-day (m = 1, 7, 14, 30, 60) rolling averages and the 95th percentiles of atrazine concentration in streams where data were collected every 7 or 14 d. The universal kriging predictions were evaluated against the target quantities calculated directly from the daily (or near daily) measured atrazine concentration at 32 sites (89 site-yr) as part of the Atrazine Ecological Monitoring Program in the US corn belt region (2008-2013) and 4 sites (62 site-yr) in Ohio by the National Center for Water Quality Research (1993-2008). Because stream flow data are strongly skewed to the right, 3 transformations of the flow covariate were considered: log transformation, short-term flow anomaly, and normalized Box-Cox transformation. The normalized Box-Cox transformation resulted in predictions of the target quantities that were comparable to those obtained from log-linear interpolation (i.e., linear interpolation on the log scale) for 7-d sampling. However, the predictions appeared to be negatively affected by variability in regression coefficient estimates across different sample realizations of the concentration time series. Therefore, revised models incorporating seasonal covariates and partially or fully constrained regression parameters were investigated, and they were found to provide much improved predictions in comparison with those from log-linear interpolation for all rolling average measures. Environ Toxicol Chem 2018;37:260-273. © 2017 SETAC. © 2017 SETAC.

  10. Switch of flow direction in an Antarctic ice stream.

    Science.gov (United States)

    Conway, H; Catania, G; Raymond, C F; Gades, A M; Scambos, T A; Engelhardt, H

    2002-10-03

    Fast-flowing ice streams transport ice from the interior of West Antarctica to the ocean, and fluctuations in their activity control the mass balance of the ice sheet. The mass balance of the Ross Sea sector of the West Antarctic ice sheet is now positive--that is, it is growing--mainly because one of the ice streams (ice stream C) slowed down about 150 years ago. Here we present evidence from both surface measurements and remote sensing that demonstrates the highly dynamic nature of the Ross drainage system. We show that the flow in an area that once discharged into ice stream C has changed direction, now draining into the Whillans ice stream (formerly ice stream B). This switch in flow direction is a result of continuing thinning of the Whillans ice stream and recent thickening of ice stream C. Further abrupt reorganization of the activity and configuration of the ice streams over short timescales is to be expected in the future as the surface topography of the ice sheet responds to the combined effects of internal dynamics and long-term climate change. We suggest that caution is needed when using observations of short-term mass changes to draw conclusions about the large-scale mass balance of the ice sheet.

  11. Time-dependent 2-stream particle transport

    International Nuclear Information System (INIS)

    Corngold, Noel

    2015-01-01

    Highlights: • We consider time-dependent transport in the 2-stream or “rod” model via an attractive matrix formalism. • After reviewing some classical problems in homogeneous media we discuss transport in materials with whose density may vary. • There we achieve a significant contraction of the underlying Telegrapher’s equation. • We conclude with a discussion of stochastics, treated by the “first-order smoothing approximation.” - Abstract: We consider time-dependent transport in the 2-stream or “rod” model via an attractive matrix formalism. After reviewing some classical problems in homogeneous media we discuss transport in materials whose density may vary. There we achieve a significant contraction of the underlying Telegrapher’s equation. We conclude with a discussion of stochastics, treated by the “first-order smoothing approximation.”

  12. Particle migration and sorting in microbubble streaming flows

    Science.gov (United States)

    Thameem, Raqeeb; Hilgenfeldt, Sascha

    2016-01-01

    Ultrasonic driving of semicylindrical microbubbles generates strong streaming flows that are robust over a wide range of driving frequencies. We show that in microchannels, these streaming flow patterns can be combined with Poiseuille flows to achieve two distinctive, highly tunable methods for size-sensitive sorting and trapping of particles much smaller than the bubble itself. This method allows higher throughput than typical passive sorting techniques, since it does not require the inclusion of device features on the order of the particle size. We propose a simple mechanism, based on channel and flow geometry, which reliably describes and predicts the sorting behavior observed in experiment. It is also shown that an asymptotic theory that incorporates the device geometry and superimposed channel flow accurately models key flow features such as peak speeds and particle trajectories, provided it is appropriately modified to account for 3D effects caused by the axial confinement of the bubble. PMID:26958103

  13. Counter-streaming flows in a giant quiet-Sun filament observed in the extreme ultraviolet

    Science.gov (United States)

    Diercke, A.; Kuckein, C.; Verma, M.; Denker, C.

    2018-03-01

    Aim. The giant solar filament was visible on the solar surface from 2011 November 8-23. Multiwavelength data from the Solar Dynamics Observatory (SDO) were used to examine counter-streaming flows within the spine of the filament. Methods: We use data from two SDO instruments, the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI), covering the whole filament, which stretched over more than half a solar diameter. Hα images from the Kanzelhöhe Solar Observatory (KSO) provide context information of where the spine of the filament is defined and the barbs are located. We apply local correlation tracking (LCT) to a two-hour time series on 2011 November 16 of the AIA images to derive horizontal flow velocities of the filament. To enhance the contrast of the AIA images, noise adaptive fuzzy equalization (NAFE) is employed, which allows us to identify and quantify counter-streaming flows in the filament. We observe the same cool filament plasma in absorption in both Hα and EUV images. Hence, the counter-streaming flows are directly related to this filament material in the spine. In addition, we use directional flow maps to highlight the counter-streaming flows. Results: We detect counter-streaming flows in the filament, which are visible in the time-lapse movies in all four examined AIA wavelength bands (λ171 Å, λ193 Å, λ304 Å, and λ211 Å). In the time-lapse movies we see that these persistent flows lasted for at least two hours, although they became less prominent towards the end of the time series. Furthermore, by applying LCT to the images we clearly determine counter-streaming flows in time series of λ171 Å and λ193 Å images. In the λ304 Å wavelength band, we only see minor indications for counter-streaming flows with LCT, while in the λ211 Å wavelength band the counter-streaming flows are not detectable with this method. The diverse morphology of the filament in Hα and EUV images is caused by different absorption

  14. Shade and flow effects on ammonia retention in macrophyte-rich streams: implications for water quality

    International Nuclear Information System (INIS)

    Wilcock, Robert J.; Scarsbrook, Mike R.; Cooke, James G.; Costley, Kerry J.; Nagels, John W.

    2004-01-01

    Controlled releases of NH 4 -N and conservative tracers (Br - and Cl - ) to five reaches of four streams with contrasting macrophyte communities have shown differing retentions, largely as a result of the way plants interact with stream flow and velocity. First-order constants (k) were 1.0-4.8 d -1 and retention of NH 4 -N was 6-71% of amounts added to each reach. Distance travelled before a 50% reduction in concentration was achieved were 40-450 m in three streams under low-flow conditions, and 2400-3800 m at higher flows. Retention (%) of NH 4 -N can be approximated by a simple function of travel time and k, highlighting the importance of the relationship between macrophytes and stream velocity on nutrient processing. This finding has significant management implications, particularly with respect to restoration of riparian shade. Small streams with predominantly marginal emergent plants are likely to have improved retention of NH 4 -N as a result of shading or other means of reducing plant biomass. Streams dominated by submerged macrophytes will have impaired NH 4 -N retention if plant biomass is reduced because of reduced contact times between NH 4 -N molecules and reactive sites. In these conditions water resource managers should utilise riparian shading in concert with unshaded vegetated reaches to achieve a balance between enhanced in-stream habitat and nutrient processing capacity

  15. Dating base flow in streams using dissolved gases and diurnal temperature changes

    Science.gov (United States)

    Sanford, Ward E.; Casile, Gerolamo C.; Haase, Karl B.

    2015-01-01

    A method is presented for using dissolved CFCs or SF6 to estimate the apparent age of stream base flow by indirectly estimating the mean concentration of the tracer in the inflowing groundwater. The mean value is estimated simultaneously with the mean residence times of the gas and water in the stream by sampling the stream for one or both age tracers, along with dissolved nitrogen and argon at a single location over a period of approximately 12–14 h. The data are fitted to an equation representing the temporal in-stream gas exchange as it responds to the diurnal temperature fluctuation. The efficacy of the method is demonstrated by collecting and analyzing samples at six different stream locations across parts of northern Virginia, USA. The studied streams drain watersheds with areas of between 2 and 122 km2 during periods when the diurnal stream temperature ranged between 2 and 5°C. The method has the advantage of estimating the mean groundwater residence time of discharge from the watershed to the stream without the need for the collection of groundwater infiltrating to streambeds or local groundwater sampled from shallow observation wells near the stream.

  16. Natural stream flow-rates measurements by tracer techniques

    International Nuclear Information System (INIS)

    Cuellar Mansilla, J.

    1982-01-01

    This paper presents the study of the precision obtained measuring the natural stream flow rates by tracer techniques, especially when the system presents a great slope and a bed constituted by large and extended particle size. The experiences were realized in laboratory pilot channels with flow-rates between 15 and 130 [1/s]; and in natural streams with flow-rates from 1 to 25 m 3 /s. Tracer used were In-133m and Br-82 for laboratory and field measurements respectively. In both cases the tracer was injected as a pulse and its dilution measured collecting samples in the measured section, at constant flow-rates, of 5[1] in laboratory experiences and 60[1] of water in field experiences. Precisions obtained at a 95% confidence level were about 2% for laboratory and 3% for field. (I.V.)

  17. Altered stream-flow regimes and invasive plant species: The Tamarix case

    Science.gov (United States)

    Stromberg, J.C.; Lite, S.J.; Marler, R.; Paradzick, C.; Shafroth, P.B.; Shorrock, D.; White, J.M.; White, M.S.

    2007-01-01

    Aim: To test the hypothesis that anthropogenic alteration of stream-flow regimes is a key driver of compositional shifts from native to introduced riparian plant species. Location: The arid south-western United States; 24 river reaches in the Gila and Lower Colorado drainage basins of Arizona. Methods: We compared the abundance of three dominant woody riparian taxa (native Populus fremontii and Salix gooddingii, and introduced Tamarix) between river reaches that varied in stream-flow permanence (perennial vs. intermittent), presence or absence of an upstream flow-regulating dam, and presence or absence of municipal effluent as a stream water source. Results: Populus and Salix were the dominant pioneer trees along the reaches with perennial flow and a natural flood regime. In contrast, Tamarix had high abundance (patch area and basal area) along reaches with intermittent stream flows (caused by natural and cultural factors), as well as those with dam-regulated flows. Main conclusions: Stream-flow regimes are strong determinants of riparian vegetation structure, and hydrological alterations can drive dominance shifts to introduced species that have an adaptive suite of traits. Deep alluvial groundwater on intermittent rivers favours the deep-rooted, stress-adapted Tamarix over the shallower-rooted and more competitive Populus and Salix. On flow-regulated rivers, shifts in flood timing favour the reproductively opportunistic Tamarix over Populus and Salix, both of which have narrow germination windows. The prevailing hydrological conditions thus favour a new dominant pioneer species in the riparian corridors of the American Southwest. These results reaffirm the importance of reinstating stream-flow regimes (inclusive of groundwater flows) for re-establishing the native pioneer trees as the dominant forest type. ?? 2007 The Authors Journal compilation ?? 2007 Blackwell Publishing Ltd.

  18. Methods for estimating low-flow statistics for Massachusetts streams

    Science.gov (United States)

    Ries, Kernell G.; Friesz, Paul J.

    2000-01-01

    Methods and computer software are described in this report for determining flow duration, low-flow frequency statistics, and August median flows. These low-flow statistics can be estimated for unregulated streams in Massachusetts using different methods depending on whether the location of interest is at a streamgaging station, a low-flow partial-record station, or an ungaged site where no data are available. Low-flow statistics for streamgaging stations can be estimated using standard U.S. Geological Survey methods described in the report. The MOVE.1 mathematical method and a graphical correlation method can be used to estimate low-flow statistics for low-flow partial-record stations. The MOVE.1 method is recommended when the relation between measured flows at a partial-record station and daily mean flows at a nearby, hydrologically similar streamgaging station is linear, and the graphical method is recommended when the relation is curved. Equations are presented for computing the variance and equivalent years of record for estimates of low-flow statistics for low-flow partial-record stations when either a single or multiple index stations are used to determine the estimates. The drainage-area ratio method or regression equations can be used to estimate low-flow statistics for ungaged sites where no data are available. The drainage-area ratio method is generally as accurate as or more accurate than regression estimates when the drainage-area ratio for an ungaged site is between 0.3 and 1.5 times the drainage area of the index data-collection site. Regression equations were developed to estimate the natural, long-term 99-, 98-, 95-, 90-, 85-, 80-, 75-, 70-, 60-, and 50-percent duration flows; the 7-day, 2-year and the 7-day, 10-year low flows; and the August median flow for ungaged sites in Massachusetts. Streamflow statistics and basin characteristics for 87 to 133 streamgaging stations and low-flow partial-record stations were used to develop the equations. The

  19. Comparative Measurement of Stream Flow in the Ethiope River for ...

    African Journals Online (AJOL)

    This study investigates comparative measurement of stream flow in the Ethiope River for small hydropower development. Two methods – the Float and Current Meter or Bridge Broom Methods were investigated and values compared to determine best method for optimal power generation. Depth and width measurements ...

  20. Streaming: A Media Hydrography of Televisual Flows

    Directory of Open Access Journals (Sweden)

    Ghislain Thibault

    2015-09-01

    Full Text Available This paper focuses on the continuities, rather than the ruptures, between digital television and past media forms. It situates the metaphor of “streaming” in contrast to and connection with previous fluid metaphors that have been used to describe different models of media transmission. From the early use of aqueous vocabulary that shaped popular and scientific understandings of electricity transmission to the seminal studies of mass communication concerning the flows of information, images of fluidity have long shaped cultural understandings of the inner logics of media infrastructures. Building on the work of media archaeologist Erkki Huhtamo, I approach these metaphors as “recurrent topoi” in media culture.

  1. Flow Field and Acoustic Predictions for Three-Stream Jets

    Science.gov (United States)

    Simmons, Shaun Patrick; Henderson, Brenda S.; Khavaran, Abbas

    2014-01-01

    Computational fluid dynamics was used to analyze a three-stream nozzle parametric design space. The study varied bypass-to-core area ratio, tertiary-to-core area ratio and jet operating conditions. The flowfield solutions from the Reynolds-Averaged Navier-Stokes (RANS) code Overflow 2.2e were used to pre-screen experimental models for a future test in the Aero-Acoustic Propulsion Laboratory (AAPL) at the NASA Glenn Research Center (GRC). Flowfield solutions were considered in conjunction with the jet-noise-prediction code JeNo to screen the design concepts. A two-stream versus three-stream computation based on equal mass flow rates showed a reduction in peak turbulent kinetic energy (TKE) for the three-stream jet relative to that for the two-stream jet which resulted in reduced acoustic emission. Additional three-stream solutions were analyzed for salient flowfield features expected to impact farfield noise. As tertiary power settings were increased there was a corresponding near nozzle increase in shear rate that resulted in an increase in high frequency noise and a reduction in peak TKE. As tertiary-to-core area ratio was increased the tertiary potential core elongated and the peak TKE was reduced. The most noticeable change occurred as secondary-to-core area ratio was increased thickening the secondary potential core, elongating the primary potential core and reducing peak TKE. As forward flight Mach number was increased the jet plume region decreased and reduced peak TKE.

  2. Acoustic streaming in pulsating flows through porous media

    International Nuclear Information System (INIS)

    Valverde, J.M.; Dura'n-Olivencia, F.J.

    2014-01-01

    When a body immersed in a viscous fluid is subjected to a sound wave (or, equivalently, the body oscillates in the fluid otherwise at rest) a rotational fluid stream develops across a boundary layer nearby the fluid-body interphase. This so-called acoustic streaming phenomenon is responsible for a notable enhancement of heat, mass and momentum transfer and takes place in any process involving two phases subjected to relative oscillations. Understanding the fundamental mechanisms governing acoustic streaming in two-phase flows is of great interest for a wide range of applications such as sonoprocessed fluidized bed reactors, thermoacoustic refrigerators/engines, pulsatile flows through veins/arteries, hemodialysis devices, pipes in off-shore platforms, offshore piers, vibrating structures in the power-generating industry, lab-on-a-chip microfluidics and microgravity acoustic levitation, and solar thermal collectors to name a few. The aim of engineering studies on this vast diversity of systems is oriented towards maximizing the efficiency of each particular process. Even though practical problems are usually approached from disparate disciplines without any apparent linkage, the behavior of these systems is influenced by the same underlying physics. In general, acoustic streaming occurs within the interstices of porous media and usually in the presence of externally imposed steady fluid flows, which gives rise to important effects arising from the interference between viscous boundary layers developed around nearby solid surfaces and the nonlinear coupling between the oscillating and steady flows. This paper is mainly devoted to highlighting the fundamental physics behind acoustic streaming in porous media in order to provide a simple instrument to assess the relevance of this phenomenon in each particular application. The exact microscopic Navier-Stokes equations will be numerically solved for a simplified 2D system consisting of a regular array of oscillating

  3. A biological tool to assess flow connectivity in reference temporary streams from the Mediterranean Basin

    Energy Technology Data Exchange (ETDEWEB)

    Cid, N., E-mail: ncid@ub.edu [Grup de Recerca “Freshwater Ecology and Management (FEM)”, Departament d' Ecologia, Universitat de Barcelona, Catalonia (Spain); Verkaik, I. [Grup de Recerca “Freshwater Ecology and Management (FEM)”, Departament d' Ecologia, Universitat de Barcelona, Catalonia (Spain); García-Roger, E.M. [Grup de Recerca “Freshwater Ecology and Management (FEM)”, Departament d' Ecologia, Universitat de Barcelona, Catalonia (Spain); Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València (Spain); Rieradevall, M.; Bonada, N. [Grup de Recerca “Freshwater Ecology and Management (FEM)”, Departament d' Ecologia, Universitat de Barcelona, Catalonia (Spain); Sánchez-Montoya, M.M. [Department of Ecology and Hydrology, Regional Campus of International Excellence “Campus Mare Nostrum”—University of Murcia (Spain); Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin (Germany); Gómez, R.; Suárez, M.L.; Vidal-Abarca, M.R. [Department of Ecology and Hydrology, Regional Campus of International Excellence “Campus Mare Nostrum”—University of Murcia (Spain); Demartini, D.; Buffagni, A.; Erba, S. [Instituto di Ricerca Sulle Acque (CNR-IRSA) (Italy); Karaouzas, I.; Skoulikidis, N. [Hellenic Center for Marine Research (HCMR) (Greece); Prat, N. [Grup de Recerca “Freshwater Ecology and Management (FEM)”, Departament d' Ecologia, Universitat de Barcelona, Catalonia (Spain)

    2016-01-01

    Many streams in the Mediterranean Basin have temporary flow regimes. While timing for seasonal drought is predictable, they undergo strong inter-annual variability in flow intensity. This high hydrological variability and associated ecological responses challenge the ecological status assessment of temporary streams, particularly when setting reference conditions. This study examined the effects of flow connectivity in aquatic macroinvertebrates from seven reference temporary streams across the Mediterranean Basin where hydrological variability and flow conditions are well studied. We tested for the effect of flow cessation on two streamflow indices and on community composition, and, by performing random forest and classification tree analyses we identified important biological predictors for classifying the aquatic state either as flowing or disconnected pools. Flow cessation was critical for one of the streamflow indices studied and for community composition. Macroinvertebrate families found to be important for classifying the aquatic state were Hydrophilidae, Simuliidae, Hydropsychidae, Planorbiidae, Heptageniidae and Gerridae. For biological traits, trait categories associated to feeding habits, food, locomotion and substrate relation were the most important and provided more accurate predictions compared to taxonomy. A combination of selected metrics and associated thresholds based on the most important biological predictors (i.e. Bio-AS Tool) were proposed in order to assess the aquatic state in reference temporary streams, especially in the absence of hydrological data. Although further development is needed, the tool can be of particular interest for monitoring, restoration, and conservation purposes, representing an important step towards an adequate management of temporary rivers not only in the Mediterranean Basin but also in other regions vulnerable to the effects of climate change. - Highlights: • The effect of flow connectivity on macroinvertebrate

  4. Low-flow characteristics of streams in South Carolina

    Science.gov (United States)

    Feaster, Toby D.; Guimaraes, Wladmir B.

    2017-09-22

    An ongoing understanding of streamflow characteristics of the rivers and streams in South Carolina is important for the protection and preservation of the State’s water resources. Information concerning the low-flow characteristics of streams is especially important during critical flow periods, such as during the historic droughts that South Carolina has experienced in the past few decades.Between 2008 and 2016, the U.S. Geological Survey, in cooperation with the South Carolina Department of Health and Environmental Control, updated low-flow statistics at 106 continuous-record streamgages operated by the U.S. Geological Survey for the eight major river basins in South Carolina. The low-flow frequency statistics included the annual minimum 1-, 3-, 7-, 14-, 30-, 60-, and 90-day mean flows with recurrence intervals of 2, 5, 10, 20, 30, and 50 years, depending on the length of record available at the streamflow-gaging station. Computations of daily mean flow durations for the 5-, 10-, 25-, 50-, 75-, 90-, and 95-percent probability of exceedance also were included.This report summarizes the findings from publications generated during the 2008 to 2016 investigations. Trend analyses for the annual minimum 7-day average flows are provided as well as trend assessments of long-term annual precipitation data. Statewide variability in the annual minimum 7-day average flow is assessed at eight long-term (record lengths from 55 to 78 years) streamgages. If previous low-flow statistics were available, comparisons with the updated annual minimum 7-day average flow, having a 10-year recurrence interval, were made. In addition, methods for estimating low-flow statistics at ungaged locations near a gaged location are described.

  5. Characterization and classification of invertebrates as indicators of flow permanence in headwater streams

    Science.gov (United States)

    Headwater streams represent a large proportion of river networks and many have temporary flow. Litigation has questioned whether these streams are jurisdictional under the Clean Water Act. Our goal was to identify indicators of flow permanence by comparing invertebrate assemblage...

  6. Low-flow characteristics for selected streams in Indiana

    Science.gov (United States)

    Fowler, Kathleen K.; Wilson, John T.

    2015-01-01

    The management and availability of Indiana’s water resources increase in importance every year. Specifically, information on low-flow characteristics of streams is essential to State water-management agencies. These agencies need low-flow information when working with issues related to irrigation, municipal and industrial water supplies, fish and wildlife protection, and the dilution of waste. Industrial, municipal, and other facilities must obtain National Pollutant Discharge Elimination System (NPDES) permits if their discharges go directly to surface waters. The Indiana Department of Environmental Management (IDEM) requires low-flow statistics in order to administer the NPDES permit program. Low-flow-frequency characteristics were computed for 272 continuous-record stations. The information includes low-flow-frequency analysis, flow-duration analysis, and harmonic mean for the continuous-record stations. For those stations affected by some form of regulation, low-flow frequency curves are based on the longest period of homogeneous record under current conditions. Low-flow-frequency values and harmonic mean flow (if sufficient data were available) were estimated for the 166 partial-record stations. Partial-record stations are ungaged sites where streamflow measurements were made at base flow.

  7. Flow characterization temporary streams : using the model SIMGRO for the Evrotas basin, Greece

    NARCIS (Netherlands)

    Vernooij, M.G.M.; Querner, E.P.; Jacobs, C.; Froebrich, J.

    2011-01-01

    Tools were developed to quantify space–time development of different flow phases on a river basin scale. Such information is needed for the WFD. The spatial development of temporary streams was investigated in the Evrotas basin, Greece. We used the regional hydrological model SIMGRO in a GIS

  8. The evolution of streams in a time-dependent potential

    NARCIS (Netherlands)

    Buist, Hans J. T.; Helmi, Amina

    2015-01-01

    We study the evolution of streams in a time-dependent spherical gravitational potential. Our goal is to establish what are the imprints of this time evolution on the properties of streams as well as their observability. To this end, we have performed a suite of test-particle experiments for a host

  9. Implementation and Analysis of Real-Time Streaming Protocols.

    Science.gov (United States)

    Santos-González, Iván; Rivero-García, Alexandra; Molina-Gil, Jezabel; Caballero-Gil, Pino

    2017-04-12

    Communication media have become the primary way of interaction thanks to the discovery and innovation of many new technologies. One of the most widely used communication systems today is video streaming, which is constantly evolving. Such communications are a good alternative to face-to-face meetings, and are therefore very useful for coping with many problems caused by distance. However, they suffer from different issues such as bandwidth limitation, network congestion, energy efficiency, cost, reliability and connectivity. Hence, the quality of service and the quality of experience are considered the two most important issues for this type of communication. This work presents a complete comparative study of two of the most used protocols of video streaming, Real Time Streaming Protocol (RTSP) and the Web Real-Time Communication (WebRTC). In addition, this paper proposes two new mobile applications that implement those protocols in Android whose objective is to know how they are influenced by the aspects that most affect the streaming quality of service, which are the connection establishment time and the stream reception time. The new video streaming applications are also compared with the most popular video streaming applications for Android, and the experimental results of the analysis show that the developed WebRTC implementation improves the performance of the most popular video streaming applications with respect to the stream packet delay.

  10. Coupling nutrient uptake and energy flow in headwater streams

    Energy Technology Data Exchange (ETDEWEB)

    Mulholland, Patrick J [ORNL; Fellows, Christine [Griffith University, Nathan, Queensland, Australia; Valett, H. Maurice [Virginia Polytechnic Institute and State University (Virginia Tech); Dahm, Cliff [University of New Mexico, Albuquerque; Thomas, Steve [University of Nebraska

    2006-08-01

    Nutrient cycling and energy flow in ecosystems are tightly linked through the metabolic processes of organisms. Greater uptake of inorganic nutrients is expected to be associated with higher rates of metabolism [gross primary production (GPP) and respiration (R)], due to assimilatory demand of both autotrophs and heterotrophs. However, relationships between uptake and metabolism should vary with the relative contribution of autochthonous and allochthonous sources of organic matter. To investigate the relationship between metabolism and nutrient uptake, we used whole-stream and benthic chamber methods to measure rates of nitrate-nitrogen (NO{sub 3}-N) uptake and metabolism in four headwater streams chosen to span a range of light availability and therefore differing rates of GPP and contributions of autochthonous carbon. We coupled whole-stream metabolism with measures of NO{sub 3}-N uptake conducted repeatedly over the same stream reach during both day and night, as well as incubating benthic sediments under both light and dark conditions. NO{sub 3}-N uptake was generally greater in daylight compared to dark conditions, and although day-night differences in whole-stream uptake were not significant, light-dark differences in benthic chambers were significant at three of the four sites. Estimates of N demand indicated that assimilation by photoautotrophs could account for the majority of NO{sub 3}-N uptake at the two sites with relatively open canopies. Contrary to expectations, photoautotrophs contributed substantially to NO{sub 3}-N uptake even at the two closed-canopy sites, which had low values of GPP/R and relied heavily on allochthonous carbon to fuel R.

  11. The effect of in-stream activities on the Njoro River, Kenya. Part I: Stream flow and chemical water quality

    Science.gov (United States)

    Yillia, Paul T.; Kreuzinger, Norbert; Mathooko, Jude M.

    For shallow streams in sub-Saharan Africa, in-stream activities could be described as the actions by people and livestock, which take place within or besides stream channels. This study examined the nature of in-stream activities along a rural stream in Kenya and established the inequality in water allocation for various livelihood needs, as well as the negative impact they have on dry weather stream flow and chemical water quality. Seven locations along the stream were studied in wet and dry weather of 2006. Enumeration consisted of making head counts of people and livestock and tallying visitors at hourly intervals from 6 a.m. to 7 p.m. To estimate water abstraction, filled containers of known volume were counted and the stream was sampled to examine the impact on water quality. Water samples were obtained upstream and downstream of in-stream activities before (6 a.m.) and during (11 a.m., 6 p.m.) activities. Samples were analyzed for suspended solids, turbidity, BOD 5, total nitrogen and total phosphorus. The daily total abstraction at the middle reaches during dry weather was 120-150 m 3 day -1. More than 60% of abstraction was done by water vendors. Vended water from the stream was sold at US 3.5-7.5 per m 3 and vendors earned between US 3-6 a day. Abstracted water contributed approximately 40-60% of the total daily consumptive water use in the riparian area during dry weather but >30% of the morning stream flow was abstracted thereby upsetting stream flow in the lower reaches. The daily total water abstraction correlated positively ( R2, 0.98) and significantly ( p < 0.05) with the daily total human visit, which was diurnally periodic with two peaks, occurring between 9 a.m. and 10 a.m. and from 4 p.m. to 5 p.m. This diurnal pattern of visits and the corresponding in-stream activities affected water quality. In particular, suspended solids, turbidity and BOD 5 levels increased significantly ( p < 0.05) downstream during in-stream activities. It was concluded

  12. Validating alternative methodologies to estimate the hydrological regime of temporary streams when flow data are unavailable

    Science.gov (United States)

    Llorens, Pilar; Gallart, Francesc; Latron, Jérôme; Cid, Núria; Rieradevall, Maria; Prat, Narcís

    2016-04-01

    ) were examined. In this case, flow permanence metrics were estimated as the proportion of photographs presenting stream flow. Results indicate that for streams being more than 25% of the time dry, interviews systematically underestimated flow, but the qualitative information given by inhabitants was of great interest to understand river dynamics. On the other hand, the use of aerial photographs gave a good estimation of flow permanence, but the seasonality was conditioned to the capture date of the aerial photographs. For these reasons, we recommend to use both methodologies together.

  13. Groundwater flow and mixing in a wetland–stream system

    DEFF Research Database (Denmark)

    Karan, Sachin; Engesgaard, Peter Knudegaard; Zibar, Majken Caroline Looms

    2013-01-01

    steady-state groundwater model that was calibrated against average head observations. The model results were tested against groundwater fluxes determined from streambed temperature measurements. Discharge varied up to one order of magnitude across the stream and the model was successful in capturing...... in the top of the aquifer and immediately underneath the streambed no NO3- was detected deeper within the aquifer. An inverse relationship between NO3- and SO42- suggests that pyrite oxidation takes place in the deeper parts of the aquifer. Simulated flow path lines showed very different origins for deeper...

  14. Advanced real-time manipulation of video streams

    CERN Document Server

    Herling, Jan

    2014-01-01

    Diminished Reality is a new fascinating technology that removes real-world content from live video streams. This sensational live video manipulation actually removes real objects and generates a coherent video stream in real-time. Viewers cannot detect modified content. Existing approaches are restricted to moving objects and static or almost static cameras and do not allow real-time manipulation of video content. Jan Herling presents a new and innovative approach for real-time object removal with arbitrary camera movements.

  15. Ptaquiloside from bracken in stream water at base flow and during storm events

    DEFF Research Database (Denmark)

    Clauson-Kaas, Frederik; Ramwell, Carmel; Hansen, Hans Chr. Bruun

    2016-01-01

    not decrease over the course of the event. In the stream, the throughfall contribution to PTA cannot be separated from a possible below-ground input from litter, rhizomes and soil. Catchment-specific factors such as the soil pH, topography, hydrology, and bracken coverage will evidently affect the level of PTA...... rainfall and PTA concentration in the stream, with a reproducible time lag of approx. 1 h from onset of rain to elevated concentrations, and returning rather quickly (about 2 h) to base flow concentration levels. The concentration of PTA behaved similar to an inert tracer (Cl(-)) in the pulse experiment...

  16. Interactions between hyporheic flow produced by stream meanders, bars, and dunes

    Science.gov (United States)

    Stonedahl, Susa H.; Harvey, Judson W.; Packman, Aaron I.

    2013-01-01

    Stream channel morphology from grain-scale roughness to large meanders drives hyporheic exchange flow. In practice, it is difficult to model hyporheic flow over the wide spectrum of topographic features typically found in rivers. As a result, many studies only characterize isolated exchange processes at a single spatial scale. In this work, we simulated hyporheic flows induced by a range of geomorphic features including meanders, bars and dunes in sand bed streams. Twenty cases were examined with 5 degrees of river meandering. Each meandering river model was run initially without any small topographic features. Models were run again after superimposing only bars and then only dunes, and then run a final time after including all scales of topographic features. This allowed us to investigate the relative importance and interactions between flows induced by different scales of topography. We found that dunes typically contributed more to hyporheic exchange than bars and meanders. Furthermore, our simulations show that the volume of water exchanged and the distributions of hyporheic residence times resulting from various scales of topographic features are close to, but not linearly additive. These findings can potentially be used to develop scaling laws for hyporheic flow that can be widely applied in streams and rivers.

  17. Stream biofilm responses to flow intermittency: from cells to ecosystems

    Directory of Open Access Journals (Sweden)

    Sergi eSabater

    2016-03-01

    Full Text Available Temporary streams are characterized by the alternation of dry and wet hydrological phases, creating both a harsh environment for the biota as well as a high diversity of opportunities for adaptation. These systems are eminently microbial-based during several of these hydrological phases, and those growing on all solid substrata (biofilms accordingly change their physical structure and community composition. Biofilms experience large decreases on cell densities and biomass, both of bacteria and algae, during dryness. Algal and bacterial communities show remarkable decreases in their diversity, at least locally (at the habitat scale. Biofilms also respond with significant physiological plasticity to each of the hydrological changes. The decreasing humidity of the substrata through the drying process, and the changing quantity and quality of organic matter and nutrients available in the stream during that process, causes unequal responses on the biofilm bacteria and algae. Biofilm algae are affected faster than bacteria by the hydric stress, and as a result the ecosystem respiration resists longer than gross primary production to the increasing duration of flow intermittency. This response implies enhancing ecosystem heterotrophy, a pattern that can be exacerbated in temporary streams suffering of longer dry periods under global change.

  18. Specification and Compilation of Real-Time Stream Processing Applications

    NARCIS (Netherlands)

    Geuns, S.J.

    2015-01-01

    This thesis is concerned with the specification, compilation and corresponding temporal analysis of real-time stream processing applications that are executed on embedded multiprocessor systems. An example of such applications are software defined radio applications. These applications typically

  19. Three-dimensional features on oscillating microbubbles streaming flows

    Science.gov (United States)

    Rossi, Massimiliano; Marin, Alvaro G.; Wang, Cheng; Hilgenfeldt, Sascha; Kähler, Christian J.

    2013-11-01

    Ultrasound-driven oscillating micro-bubbles have been used as active actuators in microfluidic devices to perform manifold tasks such as mixing, sorting and manipulation of microparticles. A common configuration consists in side-bubbles, created by trapping air pockets in blind channels perpendicular to the main channel direction. This configuration results in bubbles with a semi-cylindrical shape that creates a streaming flow generally considered quasi two-dimensional. However, recent experiments performed with three-dimensional velocimetry methods have shown how microparticles can present significant three-dimensional trajectories, especially in regions close to the bubble interface. Several reasons will be discussed such as boundary effects of the bottom/top wall, deformation of the bubble interface leading to more complex vibrational modes, or bubble-particle interactions. In the present investigation, precise measurements of particle trajectories close to the bubble interface will be performed by means of 3D Astigmatic Particle Tracking Velocimetry. The results will allow us to characterize quantitatively the three-dimensional features of the streaming flow and to estimate its implications in practical applications as particle trapping, sorting or mixing.

  20. A biological tool to assess flow connectivity in reference temporary streams from the Mediterranean Basin.

    Science.gov (United States)

    Cid, N; Verkaik, I; García-Roger, E M; Rieradevall, M; Bonada, N; Sánchez-Montoya, M M; Gómez, R; Suárez, M L; Vidal-Abarca, M R; Demartini, D; Buffagni, A; Erba, S; Karaouzas, I; Skoulikidis, N; Prat, N

    2016-01-01

    Many streams in the Mediterranean Basin have temporary flow regimes. While timing for seasonal drought is predictable, they undergo strong inter-annual variability in flow intensity. This high hydrological variability and associated ecological responses challenge the ecological status assessment of temporary streams, particularly when setting reference conditions. This study examined the effects of flow connectivity in aquatic macroinvertebrates from seven reference temporary streams across the Mediterranean Basin where hydrological variability and flow conditions are well studied. We tested for the effect of flow cessation on two streamflow indices and on community composition, and, by performing random forest and classification tree analyses we identified important biological predictors for classifying the aquatic state either as flowing or disconnected pools. Flow cessation was critical for one of the streamflow indices studied and for community composition. Macroinvertebrate families found to be important for classifying the aquatic state were Hydrophilidae, Simuliidae, Hydropsychidae, Planorbiidae, Heptageniidae and Gerridae. For biological traits, trait categories associated to feeding habits, food, locomotion and substrate relation were the most important and provided more accurate predictions compared to taxonomy. A combination of selected metrics and associated thresholds based on the most important biological predictors (i.e. Bio-AS Tool) were proposed in order to assess the aquatic state in reference temporary streams, especially in the absence of hydrological data. Although further development is needed, the tool can be of particular interest for monitoring, restoration, and conservation purposes, representing an important step towards an adequate management of temporary rivers not only in the Mediterranean Basin but also in other regions vulnerable to the effects of climate change. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. The impact of Indian Ocean high pressure system on rainfall and stream flow

    International Nuclear Information System (INIS)

    Rehman, S.; Nasir, H.; Zia, S.S.; Ansari, W.A.; Salam, K.; Tayyab, N.

    2012-01-01

    Centre of Action approach is very useful in getting insight of rainfall and stream flow variability of specific region. Hameed et al. showed that Inter-annual variability of Gulf Stream north wall is influenced by low Icelandic pressure system and has more statistically significant correlation than North Atlantic Oscillation (NAO) with longitude of Icelandic low. This study also aims to explore possible relationships between rainfall and stream flow in Collie river catchment in Southwest Western Australia (SWWA) with Indian Ocean high pressure dynamics. The relationship between rainfall and stream flow with Indian Ocean high pressure system have been investigated using correlation analysis for early winter season (MJJA), lag correlation for MJJA versus SOND rainfall and stream flow are also calculated and found significant at 95% confidence level. By investigating the relationship between COA indices with rainfall and stream flow over the period 1976-2008, significant correlations suggests that rainfall and stream flow in Collie river basin is strongly influenced by COA indices. Multiple correlations between rainfall and stream flow with Indian Ocean high pressure (IOHPS and IOHLN) is 0.7 and 0.6 respectively. Centers of Action (COA) indices explain 51% and 36% of rainfall and stream flow respectively. The correlation between rainfall and stream flow with IOHPS is -0.4 and -0.3 whereas, with IOHLN is -0.47 and -0.52 respectively. (author)

  2. Adjusting patients streaming initiated by a wait time threshold in emergency department for minimizing opportunity cost.

    Science.gov (United States)

    Kim, Byungjoon B J; Delbridge, Theodore R; Kendrick, Dawn B

    2017-07-10

    Purpose Two different systems for streaming patients were considered to improve efficiency measures such as waiting times (WTs) and length of stay (LOS) for a current emergency department (ED). A typical fast track area (FTA) and a fast track with a wait time threshold (FTW) were designed and compared effectiveness measures from the perspective of total opportunity cost of all patients' WTs in the ED. The paper aims to discuss these issues. Design/methodology/approach This retrospective case study used computerized ED patient arrival to discharge time logs (between July 1, 2009 and June 30, 2010) to build computer simulation models for the FTA and fast track with wait time threshold systems. Various wait time thresholds were applied to stream different acuity-level patients. National average wait time for each acuity level was considered as a threshold to stream patients. Findings The fast track with a wait time threshold (FTW) showed a statistically significant shorter total wait time than the current system or a typical FTA system. The patient streaming management would improve the service quality of the ED as well as patients' opportunity costs by reducing the total LOS in the ED. Research limitations/implications The results of this study were based on computer simulation models with some assumptions such as no transfer times between processes, an arrival distribution of patients, and no deviation of flow pattern. Practical implications When the streaming of patient flow can be managed based on the wait time before being seen by a physician, it is possible for patients to see a physician within a tolerable wait time, which would result in less crowded in the ED. Originality/value A new streaming scheme of patients' flow may improve the performance of fast track system.

  3. Continental slope sea level and flow variability induced by lateral movements of the Gulf Stream in the Middle Atlantic Bight

    Science.gov (United States)

    Böhm, E.; Hopkins, T. S.; Pietrafesa, L. J.; Churchill, J. H.

    2006-08-01

    As described by [Csanady, G.T., Hamilton, P., 1988. Circulation of slope water. Continental Shelf Research 8, 565-624], the flow regime over the slope of the southern Middle Atlantic Bight (MAB) includes a current reversal in which southwestward flow over the upper and middle slope becomes entrained in the northeastward current adjacent to the Gulf Stream. In this paper we use satellite-derived data to quantify how lateral motions of the Gulf Stream impact this current system. In our analysis, the Gulf Stream’s thermal front is delineated using a two-year time series of sea surface temperature derived from NOAA/AVHRR satellite data. Lateral motions of the Gulf Stream are represented in terms of temporal variations of the area, east of 73°W, between the Gulf Stream thermal front and the shelf edge. Variations of slope water flow within this area are represented by anomalies of geostrophic velocity as derived from the time series of the sea level anomaly determined from TOPEX/POSEIDON satellite altimeter data. A strong statistical relationship is found between Gulf Stream displacements and parabathic flow over the continental slope. It is such that the southwestward flow over the slope is accelerated when the Gulf Stream is relatively far from the shelf edge, and is decelerated (and perhaps even reversed) when the Gulf Stream is close to the shelf edge. This relationship between Gulf Stream displacements and parabathic flow is also observed in numerical simulations produced by the Miami Isopycnic Coordinate Model. In qualitative terms, it is consistent with the notion that when the Gulf Stream is closer to the 200-m isobath, it is capable of entraining a larger fraction of shelf water masses. Alternatively, when the Gulf Stream is far from the shelf-break, more water is advected into the MAB slope region from the northeast. Analysis of the diabathic flow indicates that much of the cross-slope transport by which the southwestward flow entering the study region is

  4. A real time sorting algorithm to time sort any deterministic time disordered data stream

    Science.gov (United States)

    Saini, J.; Mandal, S.; Chakrabarti, A.; Chattopadhyay, S.

    2017-12-01

    In new generation high intensity high energy physics experiments, millions of free streaming high rate data sources are to be readout. Free streaming data with associated time-stamp can only be controlled by thresholds as there is no trigger information available for the readout. Therefore, these readouts are prone to collect large amount of noise and unwanted data. For this reason, these experiments can have output data rate of several orders of magnitude higher than the useful signal data rate. It is therefore necessary to perform online processing of the data to extract useful information from the full data set. Without trigger information, pre-processing on the free streaming data can only be done with time based correlation among the data set. Multiple data sources have different path delays and bandwidth utilizations and therefore the unsorted merged data requires significant computational efforts for real time manifestation of sorting before analysis. Present work reports a new high speed scalable data stream sorting algorithm with its architectural design, verified through Field programmable Gate Array (FPGA) based hardware simulation. Realistic time based simulated data likely to be collected in an high energy physics experiment have been used to study the performance of the algorithm. The proposed algorithm uses parallel read-write blocks with added memory management and zero suppression features to make it efficient for high rate data-streams. This algorithm is best suited for online data streams with deterministic time disorder/unsorting on FPGA like hardware.

  5. Riparian indicators of flow frequency in a tropical montante stream network

    Science.gov (United States)

    Andrew S. Pike; Frederick N. Scatena

    2010-01-01

    Many field indicators have been used to approximate the magnitude and frequency of flows in a variety of streams and rivers, yet due to a scarcity of long-term flow records in tropical mountain streams, little to no work has been done to establish such relationships between field features and the flow regime in these environments. Furthermore, the transition between...

  6. Toward Design Guidelines for Stream Restoration Structures: Measuring and Modeling Unsteady Turbulent Flows in Natural Streams with Complex Hydraulic Structures

    Science.gov (United States)

    Lightbody, A.; Sotiropoulos, F.; Kang, S.; Diplas, P.

    2009-12-01

    Despite their widespread application to prevent lateral river migration, stabilize banks, and promote aquatic habitat, shallow transverse flow training structures such as rock vanes and stream barbs lack quantitative design guidelines. Due to the lack of fundamental knowledge about the interaction of the flow field with the sediment bed, existing engineering standards are typically based on various subjective criteria or on cross-sectionally-averaged shear stresses rather than local values. Here, we examine the performance and stability of in-stream structures within a field-scale single-threaded sand-bed meandering stream channel in the newly developed Outdoor StreamLab (OSL) at the St. Anthony Falls Laboratory (SAFL). Before and after the installation of a rock vane along the outer bank of the middle meander bend, high-resolution topography data were obtained for the entire 50-m-long reach at 1-cm spatial scale in the horizontal and sub-millimeter spatial scale in the vertical. In addition, detailed measurements of flow and turbulence were obtained using acoustic Doppler velocimetry at twelve cross-sections focused on the vicinity of the structure. Measurements were repeated at a range of extreme events, including in-bank flows with an approximate flow rate of 44 L/s (1.4 cfs) and bankfull floods with an approximate flow rate of 280 L/s (10 cfs). Under both flow rates, the structure reduced near-bank shear stresses and resulted in both a deeper thalweg and near-bank aggradation. The resulting comprehensive dataset has been used to validate a large eddy simulation carried out by SAFL’s computational fluid dynamics model, the Virtual StreamLab (VSL). This versatile computational framework is able to efficiently simulate 3D unsteady turbulent flows in natural streams with complex in-stream structures and as a result holds promise for the development of much-needed quantitative design guidelines.

  7. Characterization of Flow Paths, Residence Time and Media Chemistry in Complex Landscapes to Integrate Surface, Groundwater and Stream Processes and Inform Models of Hydrologic and Water Quality Response to Land Use Activities; Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Bitew, Menberu [Univ. of Georgia Research Foundation, Inc., Athens, GA (United States); Jackson, Rhett [University of Georgia Research Foundation, Inc.

    2015-02-01

    The objective of this report is to document the methodology used to calculate the three hydro-geomorphic indices: C Index, Nhot spot, and Interflow Contributing Area (IFC Area). These indices were applied in the Upper Four Mile Creek Watershed in order to better understand the potential mechanisms controlling retention time, path lengths, and potential for nutrient and solute metabolism and exchange associated with the geomorphic configurations of the upland contributing areas, groundwater, the riparian zone, and stream channels.

  8. Theoretical study of time-dependent, ultrasound-induced acoustic streaming in microchannels.

    Science.gov (United States)

    Muller, Peter Barkholt; Bruus, Henrik

    2015-12-01

    Based on first- and second-order perturbation theory, we present a numerical study of the temporal buildup and decay of unsteady acoustic fields and acoustic streaming flows actuated by vibrating walls in the transverse cross-sectional plane of a long straight microchannel under adiabatic conditions and assuming temperature-independent material parameters. The unsteady streaming flow is obtained by averaging the time-dependent velocity field over one oscillation period, and as time increases, it is shown to converge towards the well-known steady time-averaged solution calculated in the frequency domain. Scaling analysis reveals that the acoustic resonance builds up much faster than the acoustic streaming, implying that the radiation force may dominate over the drag force from streaming even for small particles. However, our numerical time-dependent analysis indicates that pulsed actuation does not reduce streaming significantly due to its slow decay. Our analysis also shows that for an acoustic resonance with a quality factor Q, the amplitude of the oscillating second-order velocity component is Q times larger than the usual second-order steady time-averaged velocity component. Consequently, the well-known criterion v(1)≪c(s) for the validity of the perturbation expansion is replaced by the more restrictive criterion v(1)≪c(s)/Q. Our numerical model is available as supplemental material in the form of comsol model files and matlab scripts.

  9. Interpretation of stream programs: characterizing type 2 polynomial time complexity

    OpenAIRE

    Férée , Hugo; Hainry , Emmanuel; Hoyrup , Mathieu; Péchoux , Romain

    2010-01-01

    International audience; We study polynomial time complexity of type 2 functionals. For that purpose, we introduce a first order functional stream language. We give criteria, named well-founded, on such programs relying on second order interpretation that characterize two variants of type 2 polynomial complexity including the Basic Feasible Functions (BFF). These charac- terizations provide a new insight on the complexity of stream programs. Finally, we adapt these results to functions over th...

  10. Linear growth rates of resistive tearing modes with sub-Alfvénic streaming flow

    International Nuclear Information System (INIS)

    Wu, L. N.; Ma, Z. W.

    2014-01-01

    The tearing instability with sub-Alfvénic streaming flow along the external magnetic field is investigated using resistive MHD simulation. It is found that the growth rate of the tearing mode instability is larger than that without the streaming flow. With the streaming flow, there exist two Alfvén resonance layers near the central current sheet. The larger perturbation of the magnetic field in two closer Alfvén resonance layers could lead to formation of the observed cone structure and can largely enhance the development of the tearing mode for a narrower streaming flow. For a broader streaming flow, a larger separation of Alfvén resonance layers reduces the magnetic reconnection. The linear growth rate decreases with increase of the streaming flow thickness. The growth rate of the tearing instability also depends on the plasma beta (β). When the streaming flow is embedded in the current sheet, the growth rate increases with β if β  s , but decreases if β > β s . The existence of the specific value β s can be attributed to competition between the suppressing effect of β and the enhancing effect of the streaming flow on the magnetic reconnection. The critical value β s increases with increase of the streaming flow strength

  11. Spatio-temporal variability of land use/land cover change (LULCC within the Huron River: Effects on stream flows

    Directory of Open Access Journals (Sweden)

    Cheyenne Lei

    Full Text Available We investigated possible influences of land use/land cover change (LULCC and precipitation on spatiotemporal changes in extreme stream flows within the watershed of the Huron River Basin during the summer seasons from 1992 to 2011. Within the basin, the urban landscape increased from 8% to 16% during the study period, while forest and agricultural lands declined by 7%. There was an increase in landscape heterogeneity within the watershed that varied from 1.21% in 1992 to 1.34% in 2011, with agricultural practices and forest regions competing due to the expansion of varying intensities of urban development. Normalized stream discharge from multiple subwatersheds increased over time, with an average increase from 0.21 m3 s−1 m to 1.64 m3 s−1 m over the study period. Land use and precipitation affected stream discharge, with increasing urban development exhibiting a 37% chance of affecting extreme stream flows within the watershed. More importantly, much of the precipitation observed within the watershed temporally affected stream discharge based on expansion of urban settlement within the basin. This caused a higher likelihood of flashiness, as runoff is more concentrated and stream flow became more variable. We concluded that, within the watersheds of the Huron River, LULCC is the major determinant of increased stream flow and potential flooding. Keywords: Urbanization, Land use, Land cover, Climate, Hydrology, ArcGIS, FRAGSTATS

  12. Study of stream flow effects on bubble motion

    International Nuclear Information System (INIS)

    Sami, S.S.

    1983-01-01

    The formation of air bubbles at constant-pressure by submerged orifices was investigated in both quiescent and moving streams inside a vertical tube. Parameters affecting the bubble rise velocity, such as bubble generating frequency and diameter, were studied and analyzed for bubbles rising in a chain and homogeneous mixture. A special technique for measuring bubble motion parameters has been developed, tested, and employed throughout the experimental investigation. The method is based on a water-air impedance variation. Results obtained in stagnant liquid show that increasing the bubble diameter serves to increase bubble rise velocity, while an opposite trend has been observed for stream liquid where the bubble diameter increase reduces the bubble rise velocity. The increase of bubble generation frequency generally increases the bubble rise velocity. Experimental data covered with bubble radial distribution showed symmetrical profiles of bubble velocity and frequency, and the radial distribution of the velocity profiles sometimes has two maxima and one minimum depending on the liquid velocity. Finally, in stagnant liquid, a normalized correlation has been developed to predict the terminal rise velocity in terms of bubble generating frequency, bubble diameter, single bubble rise velocity, and conduit dimensions. Another correlation is presented for forced bubbly flow, where the bubble rise velocity is expressed as a function of bubble generating frequency, bubble diameter, and water superficial velocity

  13. Identification of flow paths and quantification of return flow volumes and timing at field scale

    Science.gov (United States)

    Claes, N.; Paige, G. B.; Parsekian, A.

    2017-12-01

    Flood irrigation, which constitutes a large part of agricultural water use, accounts for a significant amount of the water that is diverted from western streams. Return flow, the portion of the water applied to irrigated areas that returns to the stream, is important for maintaining base flows in streams and ecological function of riparian zones and wetlands hydrologically linked with streams. Prediction of timing and volumes of return flow during and after flood irrigation pose a challenge due to the heterogeneity of pedogenic and soil physical factors that influence vadose zone processes. In this study, we quantify volumes of return flow and potential pathways in the subsurface through a vadose zone flow model that is informed by both hydrological and geophysical observations in a Bayesian setting. We couple a two-dimensional vadose zone flow model through a Bayesian Markov Chain Monte Carlo approach with time lapse ERT, borehole NMR datasets that are collected during and after flood irrigation experiments, and soil physical lab analysis. The combination of both synthetic models and field observations leads to flow path identification and allows for quantification of volumes and timing and associated uncertainties of subsurface return that stems from flood irrigation. The quantification of the impact of soil heterogeneity enables us to translate these results to other sites and predict return flow under different soil physical settings. This is key when managing irrigation water resources and predictions of outcomes of different scenarios have to be evaluated.

  14. Acoustically Induced Streaming Flows near a Model Cod Otolith and their Potential Implications for Fish Hearing

    Energy Technology Data Exchange (ETDEWEB)

    Kotas, Charlotte W [ORNL; Rogers, Peter [Georgia Institute of Technology; Yoda, Minami [Georgia Institute of Technology

    2011-01-01

    The ears of fishes are remarkable sensors for the small acoustic disturbances associated with underwater sound. For example, each ear of the Atlantic cod (Gadus morhua) has three dense bony bodies (otoliths) surrounded by fluid and tissue, and detects sounds at frequencies from 30 to 500 Hz. Atlantic cod have also been shown to localize sounds. However, how their ears perform these functions is not fully understood. Steady streaming, or time-independent, flows near a 350% scale model Atlantic cod otolith immersed in a viscous fluid were studied to determine if these fluid flows contain acoustically relevant information that could be detected by the ear s sensory hair cells. The otolith was oscillated sinusoidally at various orientations at frequencies of 8 24 Hz, corresponding to an actual frequency range of 280 830 Hz. Phaselocked particle pathline visualizations of the resulting flows give velocity, vorticity, and rate of strain fields over a single plane of this mainly two-dimensional flow. Although the streaming flows contain acoustically relevant information, the displacements due to these flows are likely too small to explain Atlantic cod hearing abilities near threshold. The results, however, may suggest a possible mechanism for detection of ultrasound in some fish species.

  15. Effects of Urbanization on the Flow Regimes of Semi-Arid Southern California Streams

    Science.gov (United States)

    Hawley, R. J.; Bledsoe, B. P.; Stein, E. D.

    2010-12-01

    Stream channel erosion and associated habitat degradation are pervasive in streams draining urban areas in the southwestern US. The prevalence of these impacts results from the inherent sensitivity of streams in semi-arid climates to changes in flow and sediment regimes, and past inattention to management of geomorphically effective flows. Addressing this issue is difficult due to the lack of data linking ranges of flow (from small to large runoff events) to geomorphic channel response. Forty-three U. S. Geological Survey gages with record lengths greater than ~15 yrs and watershed areas less than ~250 square kilometers were used to empirically model the effects of urbanization on streams in southern California. The watersheds spanned a gradient of urban development and ranged from 0 to 23% total impervious area in 2001. With little flow control at the subdivision scale to date, most impervious area in the region is relatively well-connected to surface-drainage networks. Consequently, total impervious area was an effective surrogate for urbanization, and emerged as a significant (p approach expands on previous scaling procedures to produce histogram-style cumulative flow duration graphs for ungaged sites based on urbanization extent and other watershed descriptors. Urbanization resulted in proportionally-longer durations of all geomorphically-effective flows, with a more pronounced effect on the durations of moderate flows. For example, an average watershed from the study domain with ~20% imperviousness could experience five times as many days of mean daily flows on the order of 100 cfs (3 cubic meters per second) and approximately three times as many days on the order of 1,000 cfs (30 cubic meters per second) relative to the undeveloped setting. Increased duration of sediment-transporting flows is a primary driver of accelerated changes in channel form that are often concurrent with urbanization throughout southern California, particularly in unconfined, fine

  16. Information Flow for Timed Automata

    DEFF Research Database (Denmark)

    Nielson, Flemming; Nielson, Hanne Riis; Vasilikos, Panagiotis

    2017-01-01

    One of the key demands of cyberphysical systems is that they meet their safety goals. Timed Automata has established itself as a formalism for modelling and analysing the real-time safety aspects of cyberphysical systems. Increasingly it is also demanded that cyberphysical systems meet a number o...... of security goals for confidentiality and integrity. Information Flow Control is an approach to ensuring that there are no flows of information that violate the stated security policy....

  17. Comparison of Firefly algorithm and Artificial Immune System algorithm for lot streaming in -machine flow shop scheduling

    Directory of Open Access Journals (Sweden)

    G. Vijay Chakaravarthy

    2012-11-01

    Full Text Available Lot streaming is a technique used to split the processing of lots into several sublots (transfer batches to allow the overlapping of operations in a multistage manufacturing systems thereby shortening the production time (makespan. The objective of this paper is to minimize the makespan and total flow time of -job, -machine lot streaming problem in a flow shop with equal and variable size sublots and also to determine the optimal sublot size. In recent times researchers are concentrating and applying intelligent heuristics to solve flow shop problems with lot streaming. In this research, Firefly Algorithm (FA and Artificial Immune System (AIS algorithms are used to solve the problem. The results obtained by the proposed algorithms are also compared with the performance of other worked out traditional heuristics. The computational results shows that the identified algorithms are more efficient, effective and better than the algorithms already tested for this problem.

  18. Interactive real-time media streaming with reliable communication

    Science.gov (United States)

    Pan, Xunyu; Free, Kevin M.

    2014-02-01

    Streaming media is a recent technique for delivering multimedia information from a source provider to an end- user over the Internet. The major advantage of this technique is that the media player can start playing a multimedia file even before the entire file is transmitted. Most streaming media applications are currently implemented based on the client-server architecture, where a server system hosts the media file and a client system connects to this server system to download the file. Although the client-server architecture is successful in many situations, it may not be ideal to rely on such a system to provide the streaming service as users may be required to register an account using personal information in order to use the service. This is troublesome if a user wishes to watch a movie simultaneously while interacting with a friend in another part of the world over the Internet. In this paper, we describe a new real-time media streaming application implemented on a peer-to-peer (P2P) architecture in order to overcome these challenges within a mobile environment. When using the peer-to-peer architecture, streaming media is shared directly between end-users, called peers, with minimal or no reliance on a dedicated server. Based on the proposed software pɛvμa (pronounced [revma]), named for the Greek word meaning stream, we can host a media file on any computer and directly stream it to a connected partner. To accomplish this, pɛvμa utilizes the Microsoft .NET Framework and Windows Presentation Framework, which are widely available on various types of windows-compatible personal computers and mobile devices. With specially designed multi-threaded algorithms, the application can stream HD video at speeds upwards of 20 Mbps using the User Datagram Protocol (UDP). Streaming and playback are handled using synchronized threads that communicate with one another once a connection is established. Alteration of playback, such as pausing playback or tracking to a

  19. Sequential specification of time-aware stream processing applications

    NARCIS (Netherlands)

    Geuns, S.J.; Hausmans, J.P.H.M.; Bekooij, Marco Jan Gerrit

    Automatic parallelization of Nested Loop Programs (NLPs) is an attractive method to create embedded real-time stream processing applications for multi-core systems. However, the description and parallelization of applications with a time dependent functional behavior has not been considered in NLPs.

  20. Pesticide load dynamics during stormwater flow events in Mediterranean coastal streams: Alexander stream case study.

    Science.gov (United States)

    Topaz, Tom; Egozi, Roey; Eshel, Gil; Chefetz, Benny

    2018-06-01

    Cultivated land is a major source of pesticides, which are transported with the runoff water and eroded soil during rainfall events and pollute riverine and estuarine environments. Common ecotoxicological assessments of riverine systems are mainly based on water sampling and analysis of only the dissolved phase, and address a single pesticide's toxicological impact under laboratory conditions. A clear overview of mixtures of pesticides in the adsorbed and dissolved phases is missing, and therefore the full ecotoxicological impact is not fully addressed. The aim of this study was to characterize and quantify pesticide concentrations in both suspended sediment and dissolved phases, to provide a better understanding of pesticide-load dynamics during storm events in coastal streams in a Mediterranean climate. High-resolution sampling campaigns of seven flood events were conducted during two rainy seasons in Alexander stream, Israel. Samples of suspended sediments were separated from the solution and both media were analyzed separately for 250 pesticides. A total of 63 pesticides were detected; 18 and 16 pesticides were found solely in the suspended sediments and solution, respectively. Significant differences were observed among the pesticide groups: only 7% of herbicide, 20% of fungicide and 42% of insecticide load was transported with the suspended sediments. However, in both dissolved and adsorbed phases, a mix of pesticides was found which were graded from "mobile" to "non-mobile" with varied distribution coefficients. Diuron, and tebuconazole were frequently found in large quantities in both phases. Whereas insecticide and fungicide transport is likely governed by application time and method, the governing factor for herbicide load was the magnitude of the stream discharge. The results show a complex dynamic of pesticide load affected by excessive use of pesticides, which should be taken into consideration when designing projects to monitor riverine and estuarine

  1. Artificial intelligence based models for stream-flow forecasting: 2000-2015

    Science.gov (United States)

    Yaseen, Zaher Mundher; El-shafie, Ahmed; Jaafar, Othman; Afan, Haitham Abdulmohsin; Sayl, Khamis Naba

    2015-11-01

    The use of Artificial Intelligence (AI) has increased since the middle of the 20th century as seen in its application in a wide range of engineering and science problems. The last two decades, for example, has seen a dramatic increase in the development and application of various types of AI approaches for stream-flow forecasting. Generally speaking, AI has exhibited significant progress in forecasting and modeling non-linear hydrological applications and in capturing the noise complexity in the dataset. This paper explores the state-of-the-art application of AI in stream-flow forecasting, focusing on defining the data-driven of AI, the advantages of complementary models, as well as the literature and their possible future application in modeling and forecasting stream-flow. The review also identifies the major challenges and opportunities for prospective research, including, a new scheme for modeling the inflow, a novel method for preprocessing time series frequency based on Fast Orthogonal Search (FOS) techniques, and Swarm Intelligence (SI) as an optimization approach.

  2. FINE MAGNETIC STRUCTURE AND ORIGIN OF COUNTER-STREAMING MASS FLOWS IN A QUIESCENT SOLAR PROMINENCE

    International Nuclear Information System (INIS)

    Shen, Yuandeng; Liu, Yu; Xu, Zhi; Liu, Zhong; Liu, Ying D.; Chen, P. F.; Su, Jiangtao

    2015-01-01

    We present high-resolution observations of a quiescent solar prominence that consists of a vertical and a horizontal foot encircled by an overlying spine and has ubiquitous counter-streaming mass flows. While the horizontal foot and the spine were connected to the solar surface, the vertical foot was suspended above the solar surface and was supported by a semicircular bubble structure. The bubble first collapsed, then reformed at a similar height, and finally started to oscillate for a long time. We find that the collapse and oscillation of the bubble boundary were tightly associated with a flare-like feature located at the bottom of the bubble. Based on the observational results, we propose that the prominence should be composed of an overlying horizontal spine encircling a low-lying horizontal and vertical foot, in which the horizontal foot consists of shorter field lines running partially along the spine and has ends connected to the solar surface, while the vertical foot consists of piling-up dips due to the sagging of the spine fields and is supported by a bipolar magnetic system formed by parasitic polarities (i.e., the bubble). The upflows in the vertical foot were possibly caused by the magnetic reconnection at the separator between the bubble and the overlying dips, which intruded into the persistent downflow field and formed the picture of counter-streaming mass flows. In addition, the counter-streaming flows in the horizontal foot were possibly caused by the imbalanced pressure at the both ends

  3. Effective number of breeders provides a link between interannual variation in stream flow and individual reproductive contribution in a stream salmonid.

    Science.gov (United States)

    Whiteley, Andrew R; Coombs, Jason A; Cembrola, Matthew; O'Donnell, Matthew J; Hudy, Mark; Nislow, Keith H; Letcher, Benjamin H

    2015-07-01

    The effective number of breeders that give rise to a cohort (N(b)) is a promising metric for genetic monitoring of species with overlapping generations; however, more work is needed to understand factors that contribute to variation in this measure in natural populations. We tested hypotheses related to interannual variation in N(b) in two long-term studies of brook trout populations. We found no supporting evidence for our initial hypothesis that N^(b) reflects N^(c) (defined as the number of adults in a population at the time of reproduction). N^(b) was stable relative to N^(C) and did not follow trends in abundance (one stream negative, the other positive). We used stream flow estimates to test the alternative hypothesis that environmental factors constrain N(b). We observed an intermediate optimum autumn stream flow for both N^(b) (R(2) = 0.73, P = 0.02) and full-sibling family evenness (R(2) = 0.77, P = 0.01) in one population and a negative correlation between autumn stream flow and full-sib family evenness in the other population (r = -0.95, P = 0.02). Evidence for greater reproductive skew at the lowest and highest autumn flow was consistent with suboptimal conditions at flow extremes. A series of additional tests provided no supporting evidence for a related hypothesis that density-dependent reproductive success was responsible for the lack of relationship between N(b) and N(C) (so-called genetic compensation). This work provides evidence that N(b) is a useful metric of population-specific individual reproductive contribution for genetic monitoring across populations and the link we provide between stream flow and N(b) could be used to help predict population resilience to environmental change. © 2015 John Wiley & Sons Ltd.

  4. Aquatic insect emergence from headwater streams flowing through regeneration and mature forests in western Oregon

    Science.gov (United States)

    Robert Progar; Andrew R. Moldenke

    2009-01-01

    We examined the effect of canopy cover on adult aquatic insect emergence by collecting bi-weekly samples from twelve headwater stream reaches flowing either under a mature conifer canopy or streams flowing through ten-year-old regeneration in western Oregon from February to November 1997. Density and biomass generally followed a bimodal curve with peaks during early...

  5. Application of support vector regression (SVR) for stream flow prediction on the Amazon basin

    CSIR Research Space (South Africa)

    Du Toit, Melise

    2016-10-01

    Full Text Available regression technique is used in this study to analyse historical stream flow occurrences and predict stream flow values for the Amazon basin. Up to twelve month predictions are made and the coefficient of determination and root-mean-square error are used...

  6. Cache Timing Analysis of eStream Finalists

    DEFF Research Database (Denmark)

    Zenner, Erik

    2009-01-01

    Cache Timing Attacks have attracted a lot of cryptographic attention due to their relevance for the AES. However, their applicability to other cryptographic primitives is less well researched. In this talk, we give an overview over our analysis of the stream ciphers that were selected for phase 3...

  7. Fine particle retention within stream storage areas at base flow and in response to a storm event

    Science.gov (United States)

    Drummond, J. D.; Larsen, L. G.; González-Pinzón, R.; Packman, A. I.; Harvey, Judson

    2017-01-01

    Fine particles (1–100 µm), including particulate organic carbon (POC) and fine sediment, influence stream ecological functioning because they may contain or have a high affinity to sorb nitrogen and phosphorus. These particles are immobilized within stream storage areas, especially hyporheic sediments and benthic biofilms. However, fine particles are also known to remobilize under all flow conditions. This combination of downstream transport and transient retention, influenced by stream geomorphology, controls the distribution of residence times over which fine particles influence stream ecosystems. The main objective of this study was to quantify immobilization and remobilization rates of fine particles in a third-order sand-and-gravel bed stream (Difficult Run, Virginia, USA) within different geomorphic units of the stream (i.e., pool, lateral cavity, and thalweg). During our field injection experiment, a thunderstorm-driven spate allowed us to observe fine particle dynamics during both base flow and in response to increased flow. Solute and fine particles were measured within stream surface waters, pore waters, sediment cores, and biofilms on cobbles. Measurements were taken at four different subsurface locations with varying geomorphology and at multiple depths. Approximately 68% of injected fine particles were retained during base flow until the onset of the spate. Retention was evident even after the spate, with 15.4% of the fine particles deposited during base flow still retained within benthic biofilms on cobbles and 14.9% within hyporheic sediment after the spate. Thus, through the combination of short-term remobilization and long-term retention, fine particles can serve as sources of carbon and nutrients to downstream ecosystems over a range of time scales.

  8. Fine particle retention within stream storage areas at base flow and in response to a storm event

    Science.gov (United States)

    Drummond, J. D.; Larsen, L. G.; González-Pinzón, R.; Packman, A. I.; Harvey, J. W.

    2017-07-01

    Fine particles (1-100 µm), including particulate organic carbon (POC) and fine sediment, influence stream ecological functioning because they may contain or have a high affinity to sorb nitrogen and phosphorus. These particles are immobilized within stream storage areas, especially hyporheic sediments and benthic biofilms. However, fine particles are also known to remobilize under all flow conditions. This combination of downstream transport and transient retention, influenced by stream geomorphology, controls the distribution of residence times over which fine particles influence stream ecosystems. The main objective of this study was to quantify immobilization and remobilization rates of fine particles in a third-order sand-and-gravel bed stream (Difficult Run, Virginia, USA) within different geomorphic units of the stream (i.e., pool, lateral cavity, and thalweg). During our field injection experiment, a thunderstorm-driven spate allowed us to observe fine particle dynamics during both base flow and in response to increased flow. Solute and fine particles were measured within stream surface waters, pore waters, sediment cores, and biofilms on cobbles. Measurements were taken at four different subsurface locations with varying geomorphology and at multiple depths. Approximately 68% of injected fine particles were retained during base flow until the onset of the spate. Retention was evident even after the spate, with 15.4% of the fine particles deposited during base flow still retained within benthic biofilms on cobbles and 14.9% within hyporheic sediment after the spate. Thus, through the combination of short-term remobilization and long-term retention, fine particles can serve as sources of carbon and nutrients to downstream ecosystems over a range of time scales.

  9. Analysis of groundwater flow and stream depletion in L-shaped fluvial aquifers

    Science.gov (United States)

    Lin, Chao-Chih; Chang, Ya-Chi; Yeh, Hund-Der

    2018-04-01

    Understanding the head distribution in aquifers is crucial for the evaluation of groundwater resources. This article develops a model for describing flow induced by pumping in an L-shaped fluvial aquifer bounded by impermeable bedrocks and two nearly fully penetrating streams. A similar scenario for numerical studies was reported in Kihm et al. (2007). The water level of the streams is assumed to be linearly varying with distance. The aquifer is divided into two subregions and the continuity conditions of the hydraulic head and flux are imposed at the interface of the subregions. The steady-state solution describing the head distribution for the model without pumping is first developed by the method of separation of variables. The transient solution for the head distribution induced by pumping is then derived based on the steady-state solution as initial condition and the methods of finite Fourier transform and Laplace transform. Moreover, the solution for stream depletion rate (SDR) from each of the two streams is also developed based on the head solution and Darcy's law. Both head and SDR solutions in the real time domain are obtained by a numerical inversion scheme called the Stehfest algorithm. The software MODFLOW is chosen to compare with the proposed head solution for the L-shaped aquifer. The steady-state and transient head distributions within the L-shaped aquifer predicted by the present solution are compared with the numerical simulations and measurement data presented in Kihm et al. (2007).

  10. Analysis of groundwater flow and stream depletion in L-shaped fluvial aquifers

    Directory of Open Access Journals (Sweden)

    C.-C. Lin

    2018-04-01

    Full Text Available Understanding the head distribution in aquifers is crucial for the evaluation of groundwater resources. This article develops a model for describing flow induced by pumping in an L-shaped fluvial aquifer bounded by impermeable bedrocks and two nearly fully penetrating streams. A similar scenario for numerical studies was reported in Kihm et al. (2007. The water level of the streams is assumed to be linearly varying with distance. The aquifer is divided into two subregions and the continuity conditions of the hydraulic head and flux are imposed at the interface of the subregions. The steady-state solution describing the head distribution for the model without pumping is first developed by the method of separation of variables. The transient solution for the head distribution induced by pumping is then derived based on the steady-state solution as initial condition and the methods of finite Fourier transform and Laplace transform. Moreover, the solution for stream depletion rate (SDR from each of the two streams is also developed based on the head solution and Darcy's law. Both head and SDR solutions in the real time domain are obtained by a numerical inversion scheme called the Stehfest algorithm. The software MODFLOW is chosen to compare with the proposed head solution for the L-shaped aquifer. The steady-state and transient head distributions within the L-shaped aquifer predicted by the present solution are compared with the numerical simulations and measurement data presented in Kihm et al. (2007.

  11. Flow behaviour, suspended sediment transport and transmission losses in a small (sub-bank-full) flow event in an Australian desert stream

    Science.gov (United States)

    Dunkerley, David; Brown, Kate

    1999-08-01

    The behaviour of a discrete sub-bank-full flow event in a small desert stream in western NSW, Australia, is analysed from direct observation and sediment sampling during the flow event and from later channel surveys. The flow event, the result of an isolated afternoon thunderstorm, had a peak discharge of 9 m3/s at an upstream station. Transmission loss totally consumed the flow over the following 7·6 km. Suspended sediment concentration was highest at the flow front (not the discharge peak) and declined linearly with the log of time since passage of the flow front, regardless of discharge variation. The transmission loss responsible for the waning and eventual cessation of flow occurred at a mean rate of 13.2% per km. This is quite rapid, and is more than twice the corresponding figure for bank-full flows estimated by Dunkerley (1992) on the same stream system. It is proposed that transmission losses in ephemeral streams of the kind studied may be minimized in flows near bank-full stage, and be higher in both sub-bank-full and overbank flows. Factors contributing to enhanced flow loss in the sub-bank-full flow studied included abstractions of flow to pools, scour holes and other low points along the channel, and overflow abstractions into channel filaments that did not rejoin the main flow. On the other hand, losses were curtailed by the shallow depth of banks wetted and by extensive mud drapes that were set down over sand bars and other porous channel materials during the flow. Thus, in contrast with the relatively regular pattern of transmission loss inferred from large floods, losses from low flows exhibit marked spatial variability and depend to a considerable extent on streamwise variations in channel geometry, in addition to the depth and porosity of channel perimeter sediments.

  12. STREAM

    DEFF Research Database (Denmark)

    Godsk, Mikkel

    This paper presents a flexible model, ‘STREAM’, for transforming higher science education into blended and online learning. The model is inspired by ideas of active and collaborative learning and builds on feedback strategies well-known from Just-in-Time Teaching, Flipped Classroom, and Peer...... Instruction. The aim of the model is to provide both a concrete and comprehensible design toolkit for adopting and implementing educational technologies in higher science teaching practice and at the same time comply with diverse ambitions. As opposed to the above-mentioned feedback strategies, the STREAM...... model supports a relatively diverse use of educational technologies and may also be used to transform teaching into completely online learning. So far both teachers and educational developers have positively received the model and the initial design experiences show promise....

  13. Reverse stream flow routing by using Muskingum models

    Indian Academy of Sciences (India)

    Reverse stream flow routing is a procedure that determines the upstream hydrograph given the downstream hydrograph. This paper presents the development of methodology for Muskingum models parameter estimation for reverse stream flow routing. The standard application of the Muskingum models involves calibration ...

  14. Increasing synchrony of high temperature and low flow in western North American streams: Double trouble for coldwater biota?

    Science.gov (United States)

    Ivan Arismendi; Mohammad Safeeq; Sherri L. Johnson; Jason B Dunham; Roy Haggerty

    2013-01-01

    Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (Tmax_w) and stream flow minima (Qmin) can create periods of stress for aquatic organisms. In mountainous areas, such as western North America, recent shifts toward an earlier spring peak flow and...

  15. Effects of chronic pollution and water flow intermittency on stream biofilms biodegradation capacity.

    Science.gov (United States)

    Rožman, Marko; Acuña, Vicenç; Petrović, Mira

    2018-02-01

    A mesocosm case study was conducted to gain understanding and practical knowledge on biofilm emerging contaminants biodegradation capacity under stressor and multiple stressor conditions. Two real life scenarios: I) biodegradation in a pristine intermittent stream experiencing acute pollution and II) biodegradation in a chronically polluted intermittent stream, were examined via a multifactorial experiment using an artificial stream facility. Stream biofilms were exposed to different water flow conditions i.e. permanent and intermittent water flow. Venlafaxine, a readily biodegradable pharmaceutical was used as a measure of biodegradation capacity while pollution was simulated by a mixture of four emerging contaminants (erythromycin, sulfisoxazole, diclofenac and imidacloprid in addition to venlafaxine) in environmentally relevant concentrations. Biodegradation kinetics monitored via LC-MS/MS was established, statistically evaluated, and used to link biodegradation with stress events. The results suggest that the effects of intermittent flow do not hinder and may even stimulate pristine biofilm biodegradation capacity. Chronic pollution completely reduced biodegradation in permanent water flow experimental treatments while no change in intermittent streams was observed. A combined effect of water flow conditions and emerging contaminants exposure on biodegradation was found. The decrease in biodegradation due to exposure to emerging contaminants is significantly greater in streams with permanent water flow suggesting that the short and medium term biodegradation capacity in intermittent systems may be preserved or even greater than in perennial streams. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The Effects of the Impedance of the Flow Source on the Design of Tidal Stream Generators

    Science.gov (United States)

    Salter, S.

    2011-12-01

    The maximum performance of a wind turbine is set by the well-known Betz limit. If the designer of a wind turbine uses too fast a rotation, too large a blade chord or too high an angle of blade pitch, the air flow can take an easier path over or around the rotor. Most estimates of the tidal stream resource use equations borrowed from wind and would be reasonably accurate for a single unit. But water cannot flow through the seabed or over rotors which reach to the surface. If contra-rotating, vertical-axis turbines with a rectangular flow-window are placed close to one another and reach from the surface close to the seabed, the leakage path is blocked and they become more like turbines in a closed duct. Instead of an equation with area times velocity-cubed we should use the first power of volume flow rate though the rotor times the pressure difference across it. A long channel with a rough bed will already be losing lots of energy and will behave more like a high impedance flow. Attempts to block it with closely-packed turbines will increase the head across the turbines with only a small effect on flow rate. The same thing will occur if a close-packed line of turbines is built out to sea from a headland. It is necessary to understand the impedance of the flow source all the way out to mid-ocean. In deep seas where the current velocities at the seabed are too slow to disturb the ooze the friction coefficients will be similar to those of gloss paint, perhaps 0.0025. But the higher velocities in shallow water will remove ooze and quite large sediments leaving rough, bare rock and leading to higher friction-coefficients. Energy dissipation will be set by the higher friction coefficients and the cube of the higher velocities. The presence of turbines will reduce seabed losses and about one third of the present loss can be converted to electricity. The velocity reduction would be about 10%. In many sites the energy output will be far higher than the wind turbine equations

  17. StreamStats in Oklahoma - Drainage-Basin Characteristics and Peak-Flow Frequency Statistics for Ungaged Streams

    Science.gov (United States)

    Smith, S. Jerrod; Esralew, Rachel A.

    2010-01-01

    drainage-basin outlet for the period 1961-1990, 10-85 channel slope (slope between points located at 10 percent and 85 percent of the longest flow-path length upstream from the outlet), and percent impervious area. The Oklahoma StreamStats application interacts with the National Streamflow Statistics database, which contains the peak-flow regression equations in a previously published report. Fourteen peak-flow (flood) frequency statistics are available for computation in the Oklahoma StreamStats application. These statistics include the peak flow at 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for rural, unregulated streams; and the peak flow at 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for rural streams that are regulated by Natural Resources Conservation Service floodwater retarding structures. Basin characteristics and streamflow statistics cannot be computed for locations in playa basins (mostly in the Oklahoma Panhandle) and along main stems of the largest river systems in the state, namely the Arkansas, Canadian, Cimarron, Neosho, Red, and Verdigris Rivers, because parts of the drainage areas extend outside of the processed hydrologic units.

  18. Trail Creek II: Modeling Flow and E. Coli Concentrations in a Small Urban Stream using SWAT

    Science.gov (United States)

    Radcliffe, D. E.; Saintil, T.

    2017-12-01

    Pathogens are one of the leading causes of stream and river impairment in the State of Georgia. The common presence of fecal bacteria is driven by several factors including rapid population growth stressing pre-existing and ageing infrastructure, urbanization and poor planning, increase percent imperviousness, urban runoff, municipal discharges, sewage, pet/wildlife waste and leaky septic tanks. The Trail Creek watershed, located in Athens-Clarke County, Georgia covers about 33 km2. Stream segments within Trail Creek violate the GA standard due to high levels of fecal coliform bacteria. In this study, the Soil and Water Assessment Tool (SWAT) modeling software was used to predict E. coli bacteria concentrations during baseflow and stormflow. Census data from the county was used for human and animal population estimates and the Fecal Indicator Tool to generate the number of colony forming units of E. Coli for each source. The model was calibrated at a daily time step with one year of monitored streamflow and E. coli bacteria data using SWAT-CUP and the SUFI2 algorithm. To simulate leaking sewer lines, we added point sources in the five subbasins in the SWAT model with the greatest length of sewer line within 50 m of the stream. The flow in the point sources were set to 5% of the stream flow and the bacteria count set to that of raw sewage (30,000 cfu/100 mL). The calibrated model showed that the average load during 2003-2013 at the watershed outlet was 13 million cfu per month. Using the calibrated model, we simulated scenarios that assumed leaking sewers were repaired in one of the five subbasins with point sources. The reduction ranged from 10 to 46%, with the largest reduction in subbasin in the downtown area. Future modeling work will focus on the use of green infrastructure to address sources of bacteria.

  19. Role of submerged vegetation in the retention processes of three plant protection products in flow-through stream mesocosms.

    Science.gov (United States)

    Stang, Christoph; Wieczorek, Matthias Valentin; Noss, Christian; Lorke, Andreas; Scherr, Frank; Goerlitz, Gerhard; Schulz, Ralf

    2014-07-01

    Quantitative information on the processes leading to the retention of plant protection products (PPPs) in surface waters is not available, particularly for flow-through systems. The influence of aquatic vegetation on the hydraulic- and sorption-mediated mitigation processes of three PPPs (triflumuron, pencycuron, and penflufen; logKOW 3.3-4.9) in 45-m slow-flowing stream mesocosms was investigated. Peak reductions were 35-38% in an unvegetated stream mesocosm, 60-62% in a sparsely vegetated stream mesocosm (13% coverage with Elodea nuttallii), and in a similar range of 57-69% in a densely vegetated stream mesocosm (100% coverage). Between 89% and 93% of the measured total peak reductions in the sparsely vegetated stream can be explained by an increase of vegetation-induced dispersion (estimated with the one-dimensional solute transport model OTIS), while 7-11% of the peak reduction can be attributed to sorption processes. However, dispersion contributed only 59-71% of the peak reductions in the densely vegetated stream mesocosm, where 29% to 41% of the total peak reductions can be attributed to sorption processes. In the densely vegetated stream, 8-27% of the applied PPPs, depending on the logKOW values of the compounds, were temporarily retained by macrophytes. Increasing PPP recoveries in the aqueous phase were accompanied by a decrease of PPP concentrations in macrophytes indicating kinetic desorption over time. This is the first study to provide quantitative data on how the interaction of dispersion and sorption, driven by aquatic macrophytes, influences the mitigation of PPP concentrations in flowing vegetated stream systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Strong enhancement of streaming current power by application of two phase flow

    NARCIS (Netherlands)

    Xie, Yanbo; Sherwood, John D.; Shui, Lingling; van den Berg, Albert; Eijkel, Jan C.T.

    2011-01-01

    We show that the performance of a streaming-potential based microfluidic energy conversion system can be strongly en-hanced by the use of two phase flow. In single-phase systems, the internal conduction current induced by the streaming poten-tial limits the output power, while in a two-phase system

  1. Low-flow characteristics of streams in the Puget Sound region, Washington

    Science.gov (United States)

    Hidaka, F.T.

    1973-01-01

    Periods of low streamflow are usually the most critical factor in relation to most water uses. The purpose of this report is to present data on low-flow characteristics of streams in the Puget Sound region, Washington, and to briefly explain some of the factors that influence low flow in the various basins. Presented are data on low-flow frequencies of streams in the Puget Sound region, as gathered at 150 gaging stations. Four indexes were computed from the flow-flow-frequency curves and were used as a basis to compare the low-flow characteristics of the streams. The indexes are the (1) low-flow-yield index, expressed in unit runoff per square mile; (2) base-flow index, or the ratio of the median 7-day low flow to the average discharge; (3) slope index, or slope of annual 7-day low-flow-frequency curve; and (4) spacing index, or spread between the 7-day and 183-day low-flow-frequency curves. The indexes showed a wide variation between streams due to the complex interrelation between climate, topography, and geology. The largest low-flow-yield indexes determined--greater than 1.5 cfs (cubic feet per second) per square mile--were for streams that head at high altitudes in the Cascade and Olympic Mountains and have their sources at glaciers. The smallest low-flow-yield indexes--less than 0.5 cfs per square mile--were for the small streams that drain the lowlands adjacent to Puget Sound. Indexes between the two extremes were for nonglacial streams that head at fairly high altitudes in areas of abundant precipitation. The base-flow index has variations that can be attributed to a basin's hydrogeology, with very little influence from climate. The largest base-flow indexes were obtained for streams draining permeable unconsolidated glacial and alluvial sediments in parts of the lowlands adjacent to Puget Sound. Large volume of ground water in these materials sustain flows during late summer. The smallest indexes were computed for streams draining areas underlain by

  2. Evidence for deep sub-surface flow routing in forested upland Wales: implications for contaminant transport and stream flow generation

    Directory of Open Access Journals (Sweden)

    A. H. Haria

    2004-01-01

    Full Text Available Upland streamflow generation has traditionally been modelled as a simple rainfall-runoff mechanism. However, recent hydrochemical studies conducted in upland Wales have highlighted the potentially important role of bedrock groundwater in streamflow generation processes. To investigate these processes, a detailed and novel field study was established in the riparian zone and lower hillslopes of the Hafren catchment at Plynlimon, mid-Wales. Results from this study showed groundwater near the river behaving in a complex and most likely confined manner within depth-specific horizons. Rapid responses to rainfall in all boreholes at the study site indicated rapid recharge pathways further upslope. The different flow pathways and travel times influenced the chemical character of groundwaters with depth. Groundwaters were shown to discharge into the stream from the fractured bedrock. A lateral rapid flow horizon was also identified as a fast flow pathway immediately below the soils. This highlighted a mechanism whereby rising groundwater may pick up chemical constituents from the lower soils and transfer them quickly to the stream channel. Restrictions in this horizon resulted in groundwater upwelling into the soils at some locations indicating soil water to be sourced from both rising groundwater and rainfall. The role of bedrock groundwater in upland streamflow generation is far more complicated than previously considered, particularly with respect to residence times and flow pathways. Hence, water quality models in upland catchments that do not take account of the bedrock geology and the groundwater interactions therein will be seriously flawed. Keywords: bedrock, groundwater, Hafren, hillslope hydrology, Plynlimon, recharge, soil water, streamflow generation

  3. Stream flow - its estimation, uncertainty and interaction with groundwater and floodplains

    DEFF Research Database (Denmark)

    Poulsen, Jane Bang

    , floodplain hydraulics and sedimentation patterns has been investigated along a restored channel section of Odense stream, Denmark. Collected samples of deposited sediment, organic matter and phosphorus on the floodplain were compared with results from a 2D dynamic flow model. Three stage dependent flow...... regimes were predicted by the flow model with shifting primary overbank flow and zones of flow confluence. These dynamic flow patterns were found to correlate with the spatial deposition of total phosphorus (11.4 g m-2), organic matter (0.65 kg m-2) and sediment (4.72 kg m-2), and zones of major total...... sediment deposition coincided with the flow confluence zones. The revealed complex spatially and temporally changing floodplain flow pattern was found to play a decisive role for the deposition processes. The interaction between stream flow and groundwater from catchment to point scale has been...

  4. Effective information flow through efficient supply chain management - Value stream mapping approach Case Outokumpu Tornio Works

    OpenAIRE

    Juvonen, Piia

    2012-01-01

    ABSTRACT Juvonen, Piia Suvi Päivikki 2012. Effective information flow through efficient supply chain management -Value stream mapping approach - Case Outokumpu Tornio Works. Master`s Thesis. Kemi-Tornio University of Applied Sciences. Business and Culture. Pages 63. Appendices 2. The general aim of this thesis is to explore effective information flow through efficient supply chain management by following one of the lean management principles, value stream mapping. The specific research...

  5. Identify temporal trend of air temperature and its impact on forest stream flow in Lower Mississippi River Alluvial Valley using wavelet analysis.

    Science.gov (United States)

    Ouyang, Ying; Parajuli, Prem B; Li, Yide; Leininger, Theodor D; Feng, Gary

    2017-08-01

    Characterization of stream flow is essential to water resource management, water supply planning, environmental protection, and ecological restoration; while air temperature variation due to climate change can exacerbate stream flow and add instability to the flow. In this study, the wavelet analysis technique was employed to identify temporal trend of air temperature and its impact upon forest stream flows in Lower Mississippi River Alluvial Valley (LMRAV). Four surface water monitoring stations, which locate near the headwater areas with very few land use disturbances and the long-term data records (60-90 years) in the LMRAV, were selected to obtain stream discharge and air temperature data. The wavelet analysis showed that air temperature had an increasing temporal trend around its mean value during the past several decades in the LMRAV, whereas stream flow had a decreasing temporal trend around its average value at the same time period in the same region. Results of this study demonstrated that the climate in the LMRAV did get warmer as time elapsed and the streams were drier as a result of warmer air temperature. This study further revealed that the best way to estimate the temporal trends of air temperature and stream flow was to perform the wavelet transformation around their mean values. Published by Elsevier Ltd.

  6. Selective particle and cell capture in a continuous flow using micro-vortex acoustic streaming.

    Science.gov (United States)

    Collins, David J; Khoo, Bee Luan; Ma, Zhichao; Winkler, Andreas; Weser, Robert; Schmidt, Hagen; Han, Jongyoon; Ai, Ye

    2017-05-16

    Acoustic streaming has emerged as a promising technique for refined microscale manipulation, where strong rotational flow can give rise to particle and cell capture. In contrast to hydrodynamically generated vortices, acoustic streaming is rapidly tunable, highly scalable and requires no external pressure source. Though streaming is typically ignored or minimized in most acoustofluidic systems that utilize other acoustofluidic effects, we maximize the effect of acoustic streaming in a continuous flow using a high-frequency (381 MHz), narrow-beam focused surface acoustic wave. This results in rapid fluid streaming, with velocities orders of magnitude greater than that of the lateral flow, to generate fluid vortices that extend the entire width of a 400 μm wide microfluidic channel. We characterize the forces relevant for vortex formation in a combined streaming/lateral flow system, and use these acoustic streaming vortices to selectively capture 2 μm from a mixed suspension with 1 μm particles and human breast adenocarcinoma cells (MDA-231) from red blood cells.

  7. Real-time change detection in data streams with FPGAs

    International Nuclear Information System (INIS)

    Vega, J.; Dormido-Canto, S.; Cruz, T.; Ruiz, M.; Barrera, E.; Castro, R.; Murari, A.; Ochando, M.

    2014-01-01

    Highlights: • Automatic recognition of changes in data streams of multidimensional signals. • Detection algorithm based on testing exchangeability on-line. • Real-time and off-line applicability. • Real-time implementation in FPGAs. - Abstract: The automatic recognition of changes in data streams is useful in both real-time and off-line data analyses. This article shows several effective change-detecting algorithms (based on martingales) and describes their real-time applicability in the data acquisition systems through the use of Field Programmable Gate Arrays (FPGA). The automatic event recognition system is absolutely general and it does not depend on either the particular event to detect or the specific data representation (waveforms, images or multidimensional signals). The developed approach provides good results for change detection in both the temporal evolution of profiles and the two-dimensional spatial distribution of volume emission intensity. The average computation time in the FPGA is 210 μs per profile

  8. Relation of streams, lakes, and wetlands to groundwater flow systems

    Science.gov (United States)

    Winter, Thomas C.

    Surface-water bodies are integral parts of groundwater flow systems. Groundwater interacts with surface water in nearly all landscapes, ranging from small streams, lakes, and wetlands in headwater areas to major river valleys and seacoasts. Although it generally is assumed that topographically high areas are groundwater recharge areas and topographically low areas are groundwater discharge areas, this is true primarily for regional flow systems. The superposition of local flow systems associated with surface-water bodies on this regional framework results in complex interactions between groundwater and surface water in all landscapes, regardless of regional topographic position. Hydrologic processes associated with the surface-water bodies themselves, such as seasonally high surface-water levels and evaporation and transpiration of groundwater from around the perimeter of surface-water bodies, are a major cause of the complex and seasonally dynamic groundwater flow fields associated with surface water. These processes have been documented at research sites in glacial, dune, coastal, mantled karst, and riverine terrains. Résumé Les eaux de surface sont parties intégrantes des systèmes aquifères. Les eaux souterraines interagissent avec les eaux de surface dans presque tous les types d'environnements, depuis les petits ruisseaux, les lacs et les zones humides jusqu'aux bassins versants des vallées des grands fleuves et aux lignes de côte. Il est en général admis que les zones topographiquement hautes sont des lieux de recharge des aquifères et les zones basses des lieux de décharge, ce qui est le cas des grands systèmes aquifères régionaux. La superposition de systèmes locaux, associés à des eaux de surface, à l'organisation régionale d'écoulements souterrains résulte d'interactions complexes entre les eaux souterraines et les eaux de surface dans tous les environnements, quelle que soit la situation topographique régionale. Les processus

  9. Pool-Type Fishways: Two Different Morpho-Ecological Cyprinid Species Facing Plunging and Streaming Flows

    Science.gov (United States)

    Branco, Paulo; Santos, José M.; Katopodis, Christos; Pinheiro, António; Ferreira, Maria T.

    2013-01-01

    Fish are particularly sensitive to connectivity loss as their ability to reach spawning grounds is seriously affected. The most common way to circumvent a barrier to longitudinal connectivity, and to mitigate its impacts, is to implement a fish passage device. However, these structures are often non-effective for species with different morphological and ecological characteristics so there is a need to determine optimum dimensioning values and hydraulic parameters. The aim of this work is to study the behaviour and performance of two species with different ecological characteristics (Iberian barbel Luciobarbus bocagei–bottom oriented, and Iberian chub Squalius pyrenaicus–water column) in a full-scale experimental pool-type fishway that offers two different flow regimes–plunging and streaming. Results showed that both species passed through the surface notch more readily during streaming flow than during plunging flow. The surface oriented species used the surface notch more readily in streaming flow, and both species were more successful in moving upstream in streaming flow than in plunging flow. Streaming flow enhances upstream movement of both species, and seems the most suitable for fishways in river systems where a wide range of fish morpho-ecological traits are found. PMID:23741465

  10. Laser streaming: Turning a laser beam into a flow of liquid.

    Science.gov (United States)

    Wang, Yanan; Zhang, Qiuhui; Zhu, Zhuan; Lin, Feng; Deng, Jiangdong; Ku, Geng; Dong, Suchuan; Song, Shuo; Alam, Md Kamrul; Liu, Dong; Wang, Zhiming; Bao, Jiming

    2017-09-01

    Transforming a laser beam into a mass flow has been a challenge both scientifically and technologically. We report the discovery of a new optofluidic principle and demonstrate the generation of a steady-state water flow by a pulsed laser beam through a glass window. To generate a flow or stream in the same path as the refracted laser beam in pure water from an arbitrary spot on the window, we first fill a glass cuvette with an aqueous solution of Au nanoparticles. A flow will emerge from the focused laser spot on the window after the laser is turned on for a few to tens of minutes; the flow remains after the colloidal solution is completely replaced by pure water. Microscopically, this transformation is made possible by an underlying plasmonic nanoparticle-decorated cavity, which is self-fabricated on the glass by nanoparticle-assisted laser etching and exhibits size and shape uniquely tailored to the incident beam profile. Hydrophone signals indicate that the flow is driven via acoustic streaming by a long-lasting ultrasound wave that is resonantly generated by the laser and the cavity through the photoacoustic effect. The principle of this light-driven flow via ultrasound, that is, photoacoustic streaming by coupling photoacoustics to acoustic streaming, is general and can be applied to any liquid, opening up new research and applications in optofluidics as well as traditional photoacoustics and acoustic streaming.

  11. Methods for estimating flow-duration and annual mean-flow statistics for ungaged streams in Oklahoma

    Science.gov (United States)

    Esralew, Rachel A.; Smith, S. Jerrod

    2010-01-01

    Flow statistics can be used to provide decision makers with surface-water information needed for activities such as water-supply permitting, flow regulation, and other water rights issues. Flow statistics could be needed at any location along a stream. Most often, streamflow statistics are needed at ungaged sites, where no flow data are available to compute the statistics. Methods are presented in this report for estimating flow-duration and annual mean-flow statistics for ungaged streams in Oklahoma. Flow statistics included the (1) annual (period of record), (2) seasonal (summer-autumn and winter-spring), and (3) 12 monthly duration statistics, including the 20th, 50th, 80th, 90th, and 95th percentile flow exceedances, and the annual mean-flow (mean of daily flows for the period of record). Flow statistics were calculated from daily streamflow information collected from 235 streamflow-gaging stations throughout Oklahoma and areas in adjacent states. A drainage-area ratio method is the preferred method for estimating flow statistics at an ungaged location that is on a stream near a gage. The method generally is reliable only if the drainage-area ratio of the two sites is between 0.5 and 1.5. Regression equations that relate flow statistics to drainage-basin characteristics were developed for the purpose of estimating selected flow-duration and annual mean-flow statistics for ungaged streams that are not near gaging stations on the same stream. Regression equations were developed from flow statistics and drainage-basin characteristics for 113 unregulated gaging stations. Separate regression equations were developed by using U.S. Geological Survey streamflow-gaging stations in regions with similar drainage-basin characteristics. These equations can increase the accuracy of regression equations used for estimating flow-duration and annual mean-flow statistics at ungaged stream locations in Oklahoma. Streamflow-gaging stations were grouped by selected drainage

  12. Impact of lateral flow on the transition from connected to disconnected stream-aquifer systems

    Science.gov (United States)

    Xian, Yang; Jin, Menggui; Liu, Yanfeng; Si, Aonan

    2017-05-01

    Understanding the mechanisms by which stream water infiltrates through streambeds to recharge groundwater systems is essential to sustainable management of scarce water resources in arid and semi-arid areas. An inverted water table (IWT) can develop under a stream in response to the desaturation between the stream and underlying aquifer as the system changes from a connected to disconnected status. However, previous studies have suggested that the IWT can only occur at the bottom of a low permeability streambed in which only the vertical flow between the stream and groundwater during disconnection was assumed. In the present study, numerical simulations revealed that the lateral flow induced by capillarity or heterogeneity also plays an essential role on interactions between streams and aquifers. Three pathways were identified for the transition from connection to disconnection in homogenous systems; notably, the lowest point of an IWT can develop not only at the bottom of the streambed but also within the streambed or the aquifer in response to the initial desaturation at, above, or below the interface between the streambed and aquifer (IBSA), respectively. A sensitivity analysis indicated that in wide streams, the lowest point of an IWT only occurs at the bottom of the streambed; however, for a stream half width of 1 m above a 6 m thick sandy loam streambed, the lowest point occurs in the streambed as stream depth is less than 0.5 m. This critical stream depth increases with streambed thickness and decreases with stream width. Thus, in narrow streams the lowest point can also develop in a thick streambed under a shallow stream. In narrow streams, the lowest point also forms in the aquifer if the ratio of the hydraulic conductivity of the streambed to that of the aquifer is greater than the ratio of the streambed thickness to the sum of the stream depth and the streambed thickness; correspondingly, the streambed is thin but relatively permeable and the stream is

  13. Cutting-edge analysis of extracellular microparticles using ImageStream(X) imaging flow cytometry.

    Science.gov (United States)

    Headland, Sarah E; Jones, Hefin R; D'Sa, Adelina S V; Perretti, Mauro; Norling, Lucy V

    2014-06-10

    Interest in extracellular vesicle biology has exploded in the past decade, since these microstructures seem endowed with multiple roles, from blood coagulation to inter-cellular communication in pathophysiology. In order for microparticle research to evolve as a preclinical and clinical tool, accurate quantification of microparticle levels is a fundamental requirement, but their size and the complexity of sample fluids present major technical challenges. Flow cytometry is commonly used, but suffers from low sensitivity and accuracy. Use of Amnis ImageStream(X) Mk II imaging flow cytometer afforded accurate analysis of calibration beads ranging from 1 μm to 20 nm; and microparticles, which could be observed and quantified in whole blood, platelet-rich and platelet-free plasma and in leukocyte supernatants. Another advantage was the minimal sample preparation and volume required. Use of this high throughput analyzer allowed simultaneous phenotypic definition of the parent cells and offspring microparticles along with real time microparticle generation kinetics. With the current paucity of reliable techniques for the analysis of microparticles, we propose that the ImageStream(X) could be used effectively to advance this scientific field.

  14. Prolonged effect of fluid flow stress on the proliferative activity of mesothelial cells after abrupt discontinuation of fluid streaming

    International Nuclear Information System (INIS)

    Aoki, Shigehisa; Ikeda, Satoshi; Takezawa, Toshiaki; Kishi, Tomoya; Makino, Junichi; Uchihashi, Kazuyoshi; Matsunobu, Aki; Noguchi, Mitsuru; Sugihara, Hajime; Toda, Shuji

    2011-01-01

    Highlights: ► Late-onset peritoneal fibrosis leading to EPS remains to be elucidated. ► Fluid streaming is a potent factor for peritoneal fibrosis in PD. ► We focused on the prolonged effect of fluid streaming on mesothelial cell kinetics. ► A history of fluid streaming exposure promoted mesothelial proliferative activity. ► We have thus identified a potent new factor for late-onset peritoneal fibrosis. -- Abstract: Encapsulating peritoneal sclerosis (EPS) often develops after transfer to hemodialysis and transplantation. Both termination of peritoneal dialysis (PD) and transplantation-related factors are risks implicated in post-PD development of EPS, but the precise mechanism of this late-onset peritoneal fibrosis remains to be elucidated. We previously demonstrated that fluid flow stress induced mesothelial proliferation and epithelial–mesenchymal transition via mitogen-activated protein kinase (MAPK) signaling. Therefore, we speculated that the prolonged bioactive effect of fluid flow stress may affect mesothelial cell kinetics after cessation of fluid streaming. To investigate how long mesothelial cells stay under the bioactive effect brought on by fluid flow stress after removal of the stress, we initially cultured mesothelial cells under fluid flow stress and then cultured the cells under static conditions. Mesothelial cells exposed to fluid flow stress for a certain time showed significantly high proliferative activity compared with static conditions after stoppage of fluid streaming. The expression levels of protein phosphatase 2A, which dephosphorylates MAPK, in mesothelial cells changed with time and showed a biphasic pattern that was dependent on the duration of exposure to fluid flow stress. There were no differences in the fluid flow stress-related bioactive effects on mesothelial cells once a certain time had passed. The present findings show that fluid flow stress exerts a prolonged bioactive effect on mesothelial cells after termination

  15. Joule heating induced stream broadening in free-flow zone electrophoresis.

    Science.gov (United States)

    Dutta, Debashis

    2018-03-01

    The use of an electric field in free-flow zone electrophoresis (FFZE) automatically leads to Joule heating yielding a higher temperature at the center of the separation chamber relative to that around the channel walls. For small amounts of heat generated, this thermal effect introduces a variation in the equilibrium position of the analyte molecules due to the dependence of liquid viscosity and analyte diffusivity on temperature leading to a modification in the position of the analyte stream as well as the zone width. In this article, an analytic theory is presented to quantitate such effects of Joule heating on FFZE assays in the limit of small temperature differentials across the channel gap yielding a closed form expression for the stream position and zone variance under equilibrium conditions. A method-of-moments approach is employed to develop this analytic theory, which is further validated with numerical solutions of the governing equations. Interestingly, the noted analyses predict that Joule heating can drift the location of the analyte stream either way of its equilibrium position realized in the absence of any temperature rise in the system, and also tends to reduce zone dispersion. The extent of these modifications, however, is governed by the electric field induced temperature rise and three Péclet numbers evaluated based on the axial pressure-driven flow, transverse electroosmotic and electrophoretic solute velocities in the separation chamber. Monte Carlo simulations of the FFZE system further establish a time and a length scale over which the results from the analytic theory are valid. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A regional classification of unregulated stream flows: spatial resolution and hierarchical frameworks.

    Science.gov (United States)

    Ryan A. McManamay; Donald J. Orth; Charles A. Dolloff; Emmaneul A. Firmpong

    2012-01-01

    River regulation has resulted in substantial losses in habitat connectivity, biodiversity and ecosystem services. River managers are faced with a growing need to protect the key aspects of the natural flow regime. A practical approach to providing environmental flow standards is to create a regional framework by classifying unregulated streams into groups of similar...

  17. Real-Time Management of Multimodal Streaming Data for Monitoring of Epileptic Patients.

    Science.gov (United States)

    Triantafyllopoulos, Dimitrios; Korvesis, Panagiotis; Mporas, Iosif; Megalooikonomou, Vasileios

    2016-03-01

    New generation of healthcare is represented by wearable health monitoring systems, which provide real-time monitoring of patient's physiological parameters. It is expected that continuous ambulatory monitoring of vital signals will improve treatment of patients and enable proactive personal health management. In this paper, we present the implementation of a multimodal real-time system for epilepsy management. The proposed methodology is based on a data streaming architecture and efficient management of a big flow of physiological parameters. The performance of this architecture is examined for varying spatial resolution of the recorded data.

  18. Stream biofilm responses to flow intermittency: from cells to ecosystems

    OpenAIRE

    Sergi eSabater; Sergi eSabater; Xisca eTimoner; Carles eBorrego; Carles eBorrego; Vicenç eAcuña

    2016-01-01

    Temporary streams are characterized by the alternation of dry and wet hydrological phases, creating both a harsh environment for the biota as well as a high diversity of opportunities for adaptation. These systems are eminently microbial-based during several of these hydrological phases, and those growing on all solid substrata (biofilms) accordingly change their physical structure and community composition. Biofilms experience large decreases on cell densities and biomass, both of bacteria a...

  19. Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

    OpenAIRE

    Sabater, Sergi; Timoner, Xisca; Borrego, Carles; Acuña, Vicenç

    2016-01-01

    Temporary streams are characterized by the alternation of dry and wet hydrological phases, creating both a harsh environment for the biota as well as a high diversity of opportunities for adaptation. These systems are mainly microbial-based during several of these hydrological phases, and those growing on all solid substrata (biofilms) accordingly change their physical structure and community composition. Biofilms experience large decreases in cell densities and biomass, both of bacteria and ...

  20. Scaling Law for Cross-stream Diffusion in Microchannels under Combined Electroosmotic and Pressure Driven Flow.

    Science.gov (United States)

    Song, Hongjun; Wang, Yi; Pant, Kapil

    2013-01-01

    This paper presents an analytical study of the cross-stream diffusion of an analyte in a rectangular microchannel under combined electroosmotic flow (EOF) and pressure driven flow to investigate the heterogeneous transport behavior and spatially-dependent diffusion scaling law. An analytical model capable of accurately describing 3D steady-state convection-diffusion in microchannels with arbitrary aspect ratios is developed based on the assumption of the thin Electric Double Layer (EDL). The model is verified against high-fidelity numerical simulation in terms of flow velocity and analyte concentration profiles with excellent agreement (parametric analysis is then undertaken to interrogate the effect of the combined flow velocity field on the transport behavior in both the positive pressure gradient (PPG) and negative pressure gradient (NPG) cases. For the first time, the evolution from the spindle-shaped concentration profile in the PPG case, via the stripe-shaped profile (pure EOF), and finally to the butterfly-shaped profile in the PPG case is obtained using the analytical model along with a quantitative depiction of the spatially-dependent diffusion layer thickness and scaling law across a wide range of the parameter space.

  1. Landscape Characteristics and Variations in Longitudinal Stream Flow Contribution in two Headwater Semi-Arid Mountain Watersheds

    Science.gov (United States)

    Shakespeare, B.; Gooseff, M. N.

    2005-12-01

    Understanding what role particular catchment attributes (slope, aspect, landcover, and contributing area) play in the contribution of stream flow is important for land management decisions, especially in the semi-arid western areas of the United States. Our study site is paired small catchments (approximately 9 and 11 km2) in the headwaters of the Weber drainage basin in Northern Utah. These catchments are surrounded by Wasatch formation with loamy textured soils. One catchment is predominantly underlain by quartzite while the other catchment is mostly underlain by limestone. We measured lateral flow gains every 200 to 400 meters using salt dilution gauging techniques throughout the ~5 km long streams. These measurements were taken synoptically 3 times during the seasonal discharge recession (summer 2005). The flows ranged spatially from 4 L s-1 to 55 L s-1 and varied temporally by as much as 50% when comparing the same reaches. Using GIS software, landscape analysis of slope, aspect, contributing area, topographic convergence, riparian and hillslope area, and landcover was performed for each of the delineated stream reach contributing areas. The results were tested for correlations between lateral flow gains measured in the field and different landscape characteristics. Each of the synoptic events was compared with each other to explore effects of seasonal recession on the relationships between flow gain and landscape characteristics.

  2. Abstractions for aperiodic multiprocessor scheduling of real-time stream processing applications

    NARCIS (Netherlands)

    Hausmans, J.P.H.M.

    2015-01-01

    Embedded multiprocessor systems are often used in the domain of real-time stream processing applications to keep up with increasing power and performance requirements. Examples of such real-time stream processing applications are digital radio baseband processing and WLAN transceivers. These stream

  3. Evidence of climate change impact on stream low flow from the tropical mountain rainforest watershed in Hainan Island, China

    Science.gov (United States)

    Z. Zhou; Y. Ouyang; Z. Qiu; G. Zhou; M. Lin; Y. Li

    2017-01-01

    Stream low flow estimates are central to assessing climate change impact, water resource management, and ecosystem restoration. This study investigated the impacts of climate change upon stream low flows from a rainforest watershed in Jianfengling (JFL) Mountain, Hainan Island, China, using the low flow selection method as well as the frequency and probability analysis...

  4. IOD and ENSO impacts on the extreme stream-flows of Citarum river in Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, Netrananda; Yamashiki, Yosuke; Takara, Kaoru [Kyoto University, Disaster Prevention Research Institute, Innovative Disaster Prevention Technology and Policy Research Laboratory, Gokasho, Uji City, Kyoto (Japan); Behera, Swadhin K. [JAMSTEC, Research Institute for Global Change, Yokohama, Kanagawa (Japan); JAMSTEC, Application Laboratory, Yokohama (Japan); Yamagata, Toshio [University of Tokyo, School of Science, Bunkyo-ku, Tokyo (Japan); JAMSTEC, Application Laboratory, Yokohama (Japan)

    2012-10-15

    Extreme stream-flow events of Citarum River are derived from the daily stream-flows at the Nanjung gauge station. Those events are identified based on their persistently extreme flows for 6 or more days during boreal fall when the seasonal mean stream-flow starts peaking-up from the lowest seasonal flows of June-August. Most of the extreme events of high-streamflows were related to La Nina conditions of tropical Pacific. A few of them were also associated with the negative phases of IOD and the newly identified El Nino Modoki. Unlike the cases of extreme high streamflows, extreme low streamflow events are seen to be associated with the positive IODs. Nevertheless, it was also found that the low-stream-flow events related to positive IOD events were also associated with El Nino events except for one independent event of 1977. Because the occurrence season coincides the peak season of IOD, not only the picked extreme events are seen to fall under the IOD seasons but also there exists a statistically significant correlation of 0.51 between the seasonal IOD index and the seasonal streamflows. There also exists a significant lag correlation when IOD of June-August season leads the streamflows of September-November. A significant but lower correlation coefficient (0.39) is also found between the seasonal streamflow and El Nino for September-November season only. (orig.)

  5. IOD and ENSO impacts on the extreme stream-flows of Citarum river in Indonesia

    Science.gov (United States)

    Sahu, Netrananda; Behera, Swadhin K.; Yamashiki, Yosuke; Takara, Kaoru; Yamagata, Toshio

    2012-10-01

    Extreme stream-flow events of Citarum River are derived from the daily stream-flows at the Nanjung gauge station. Those events are identified based on their persistently extreme flows for 6 or more days during boreal fall when the seasonal mean stream-flow starts peaking-up from the lowest seasonal flows of June-August. Most of the extreme events of high-streamflows were related to La Niña conditions of tropical Pacific. A few of them were also associated with the negative phases of IOD and the newly identified El Niño Modoki. Unlike the cases of extreme high streamflows, extreme low streamflow events are seen to be associated with the positive IODs. Nevertheless, it was also found that the low-stream-flow events related to positive IOD events were also associated with El Niño events except for one independent event of 1977. Because the occurrence season coincides the peak season of IOD, not only the picked extreme events are seen to fall under the IOD seasons but also there exists a statistically significant correlation of 0.51 between the seasonal IOD index and the seasonal streamflows. There also exists a significant lag correlation when IOD of June-August season leads the streamflows of September-November. A significant but lower correlation coefficient (0.39) is also found between the seasonal streamflow and El Niño for September-November season only.

  6. Differential geometric structures of stream functions: incompressible two-dimensional flow and curvatures

    International Nuclear Information System (INIS)

    Yamasaki, K; Iwayama, T; Yajima, T

    2011-01-01

    The Okubo-Weiss field, frequently used for partitioning incompressible two-dimensional (2D) fluids into coherent and incoherent regions, corresponds to the Gaussian curvature of the stream function. Therefore, we consider the differential geometric structures of stream functions and calculate the Gaussian curvatures of some basic flows. We find the following. (I) The vorticity corresponds to the mean curvature of the stream function. Thus, the stream-function surface for an irrotational flow and that for a parallel shear flow correspond to the minimal surface and a developable surface, respectively. (II) The relationship between the coherency and the magnitude of the vorticity is interpreted by the curvatures. (III) Using the Gaussian curvature, stability of single and double point vortex streets is analyzed. The results of this analysis are compared with the well-known linear stability analysis. (IV) Conformal mapping in fluid mechanics is the physical expression of the geometric fact that the sign of the Gaussian curvature does not change in conformal mapping. These findings suggest that the curvatures of stream functions are useful for understanding the geometric structure of an incompressible 2D flow.

  7. Real Time Recognition Of Speakers From Internet Audio Stream

    Directory of Open Access Journals (Sweden)

    Weychan Radoslaw

    2015-09-01

    Full Text Available In this paper we present an automatic speaker recognition technique with the use of the Internet radio lossy (encoded speech signal streams. We show an influence of the audio encoder (e.g., bitrate on the speaker model quality. The model of each speaker was calculated with the use of the Gaussian mixture model (GMM approach. Both the speaker recognition and the further analysis were realized with the use of short utterances to facilitate real time processing. The neighborhoods of the speaker models were analyzed with the use of the ISOMAP algorithm. The experiments were based on four 1-hour public debates with 7–8 speakers (including the moderator, acquired from the Polish radio Internet services. The presented software was developed with the MATLAB environment.

  8. Influence of urbanization pattern on stream flow of a peri-urban catchment under Mediterranean climate

    Science.gov (United States)

    Ferreira, Carla S. S.; Walsh, Rory P. D.; Ferreira, António J. D.; Steenhuis, Tammo S.; Coelho, Celeste A. O.

    2015-04-01

    control streamflow particularly during dry periods. Winter runoff was 2-4 times higher than total river flow in the summer dry season in highly urbanized areas, but was 21-fold higher in winter in the least urbanized sub-catchment, denoting greater flow connectivity enhanced by increased soil moisture. Although impermeable surfaces are prone to generate overland flow, the proximity to the stream network is an important parameter determining their hydrological impacts. During the monitoring period, the enlargement of 2% of the urban area at downslope locations in the Covões sub-catchment, led to a 6% increase in the runoff coefficient. In contrast, the urban area increase from 9 to 25% mainly in upslope parts of the Quinta sub-catchment did not increase the peak streamflow due to downslope infiltration and surface retention opportunities. Despite impermeable surfaces enhance overland flow, some urban features (e.g. walls and road embankments) promote surface water retention. The presence of artificial drainage systems, on the other hand, enhances flow connectivity, leading to increasing peak flow and quicker response times (~10 minutes versus 40-50 minutes) as in the Covões sub-catchment. Urbanization impact on streamflow responses may be minimized through planning the land-use mosaic so as to maximize infiltration opportunities. Knowledge of the influence of distinct urban mosaics on flow connectivity and stream discharge is therefore important to landscape managers and should guide urban planning in order to minimize flood hazards.

  9. Base flow-driven shifts in tropical stream temperature regimes across a mean annual rainfall gradient

    Science.gov (United States)

    Ayron M. Strauch; Richard A. MacKenzie; Ralph W. Tingley

    2017-01-01

    Climate change is expected to affect air temperature and watershed hydrology, but the degree to which these concurrent changes affect stream temperature is not well documented in the tropics. How stream temperature varies over time under changing hydrologic conditions is difficult to isolate from seasonal changes in air temperature. Groundwater and bank storage...

  10. Entropy resistance analyses of a two-stream parallel flow heat exchanger with viscous heating

    International Nuclear Information System (INIS)

    Cheng Xue-Tao; Liang Xin-Gang

    2013-01-01

    Heat exchangers are widely used in industry, and analyses and optimizations of the performance of heat exchangers are important topics. In this paper, we define the concept of entropy resistance based on the entropy generation analyses of a one-dimensional heat transfer process. With this concept, a two-stream parallel flow heat exchanger with viscous heating is analyzed and discussed. It is found that the minimization of entropy resistance always leads to the maximum heat transfer rate for the discussed two-stream parallel flow heat exchanger, while the minimizations of entropy generation rate, entropy generation numbers, and revised entropy generation number do not always. (general)

  11. Method of measuring the mass flow rate of a substance entering a cocurrent fluid stream

    International Nuclear Information System (INIS)

    Cochran, H.D. Jr.

    1978-01-01

    An improved method of monitoring the mass flow rate of a substance entering a coherent fluid stream is described. The method very basically consists of heating equal sections of the fluid stream above and below the point of entry of the substance to be monitored, and measuring and comparing the resulting change in temperature of the sections. Advantage is taken of the difference in thermal characteristics of the fluid and the substance to be measured to correlate temperature differences in the sections above and below the substance feed point for providing an indication of the mass flow rate of the substance

  12. Numerical and experimental modelling of back stream flow during close-coupled gas atomization

    OpenAIRE

    Motaman, S; Mullis, AM; Borman, DJ; Cochrane, RF; McCarthy, IN

    2013-01-01

    This paper reports the numerical and experimental investigation into the effects of different gas jet mis-match angles (for an external melt nozzle wall) on the back-stream flow in close coupled gas atomization. The Pulse Laser Imaging (PLI) technique was applied for visualising the back-stream melt flow phenomena with an analogue water atomizer and the associated PLI images compared with numerical results. In the investigation a Convergent–Divergent (C–D) discrete gas jet die at five differe...

  13. Flow-Through Stream Modeling with MODFLOW and MT3D: Certainties and Limitations.

    Science.gov (United States)

    Ben Simon, Rose; Bernard, Stéphane; Meurville, Charles; Rebour, Vincent

    2015-01-01

    This paper aims to assess MODFLOW and MT3D capabilities for simulating the spread of contaminants from a river exhibiting an unusual relationship with an alluvial aquifer, with the groundwater head higher than the river head on one side and lower on the other (flow-through stream). A series of simulation tests is conducted using a simple hypothetical model so as to characterize and quantify these limitations. Simulation results show that the expected contaminant spread could be achieved with a specific configuration composed of two sets of parameters: (1) modeled object parameters (hydraulic groundwater gradient, hydraulic conductivity values of aquifer and streambed), and (2) modeling parameters (vertical discretization of aquifer, horizontal refinement of stream modeled with River [RIV] package). The influence of these various parameters on simulation results is investigated, and potential complications and errors are identified. Contaminant spread from stream to aquifer is not always reproduced by MT3D due to the RIV package's inability to simulate lateral exchange fluxes between stream and aquifer. This paper identifies the need for a MODFLOW streamflow package allowing lateral stream-aquifer interactions and streamflow routine calculations. Such developments could be of particular interest for modeling contaminated flow-through streams. © 2015, National Ground Water Association.

  14. Channel water balance and exchange with subsurface flow along a mountain headwater stream in Montana, United States

    Science.gov (United States)

    R.A. Payn; M.N. Gooseff; B.L. McGlynn; K.E. Bencala; S.M. Wondzell

    2009-01-01

    Channel water balances of contiguous reaches along streams represent a poorly understood scale of stream-subsurface interaction. We measured reach water balances along a headwater stream in Montana, United States, during summer base flow recessions. Reach water balances were estimated from series of tracer tests in 13 consecutive reaches delineated evenly along a 2.6-...

  15. Real-time WAMI streaming target tracking in fog

    Science.gov (United States)

    Chen, Yu; Blasch, Erik; Chen, Ning; Deng, Anna; Ling, Haibin; Chen, Genshe

    2016-05-01

    Real-time information fusion based on WAMI (Wide-Area Motion Imagery), FMV (Full Motion Video), and Text data is highly desired for many mission critical emergency or security applications. Cloud Computing has been considered promising to achieve big data integration from multi-modal sources. In many mission critical tasks, however, powerful Cloud technology cannot satisfy the tight latency tolerance as the servers are allocated far from the sensing platform, actually there is no guaranteed connection in the emergency situations. Therefore, data processing, information fusion, and decision making are required to be executed on-site (i.e., near the data collection). Fog Computing, a recently proposed extension and complement for Cloud Computing, enables computing on-site without outsourcing jobs to a remote Cloud. In this work, we have investigated the feasibility of processing streaming WAMI in the Fog for real-time, online, uninterrupted target tracking. Using a single target tracking algorithm, we studied the performance of a Fog Computing prototype. The experimental results are very encouraging that validated the effectiveness of our Fog approach to achieve real-time frame rates.

  16. Magnitude of flood flows for selected annual exceedance probabilities for streams in Massachusetts

    Science.gov (United States)

    Zarriello, Phillip J.

    2017-05-11

    The U.S. Geological Survey, in cooperation with the Massachusetts Department of Transportation, determined the magnitude of flood flows at selected annual exceedance prob­abilities (AEPs) at streamgages in Massachusetts and from these data developed equations for estimating flood flows at ungaged locations in the State. Flood magnitudes were deter­mined for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent AEPs at 220 streamgages, 125 of which are in Massachusetts and 95 are in the adjacent States of Connecticut, New Hamp­shire, New York, Rhode Island, and Vermont. AEP flood flows were computed for streamgages using the expected moments algorithm weighted with a recently computed regional skew­ness coefficient for New England.Regional regression equations were developed to estimate the magnitude of floods for selected AEP flows at ungaged sites from 199 selected streamgages and for 60 potential explanatory basin characteristics. AEP flows for 21 of the 125 streamgages in Massachusetts were not used in the final regional regression analysis, primarily because of regulation or redundancy. The final regression equations used general­ized least squares methods to account for streamgage record length and correlation. Drainage area, mean basin elevation, and basin storage explained 86 to 93 percent of the variance in flood magnitude from the 50- to 0.2-percent AEPs, respec­tively. The estimates of AEP flows at streamgages can be improved by using a weighted estimate that is based on the magnitude of the flood and associated uncertainty from the at-site analysis and the regional regression equations. Weighting procedures for estimating AEP flows at an ungaged site on a gaged stream also are provided that improve estimates of flood flows at the ungaged site when hydrologic characteristics do not abruptly change.Urbanization expressed as the percentage of imperviousness provided some explanatory power in the regional regression; however, it was not statistically

  17. Streaming flow from ultrasound contrast agents by acoustic waves in a blood vessel model.

    Science.gov (United States)

    Cho, Eunjin; Chung, Sang Kug; Rhee, Kyehan

    2015-09-01

    To elucidate the effects of streaming flow on ultrasound contrast agent (UCA)-assisted drug delivery, streaming velocity fields from sonicated UCA microbubbles were measured using particle image velocimetry (PIV) in a blood vessel model. At the beginning of ultrasound sonication, the UCA bubbles formed clusters and translated in the direction of the ultrasound field. Bubble cluster formation and translation were faster with 2.25MHz sonication, a frequency close to the resonance frequency of the UCA. Translation of bubble clusters induced streaming jet flow that impinged on the vessel wall, forming symmetric vortices. The maximum streaming velocity was about 60mm/s at 2.25MHz and decreased to 15mm/s at 1.0MHz for the same acoustic pressure amplitude. The effect of the ultrasound frequency on wall shear stress was more noticeable. Maximum wall shear stress decreased from 0.84 to 0.1Pa as the ultrasound frequency decreased from 2.25 to 1.0MHz. The maximum spatial gradient of the wall shear stress also decreased from 1.0 to 0.1Pa/mm. This study showed that streaming flow was induced by bubble cluster formation and translation and was stronger upon sonication by an acoustic wave with a frequency near the UCA resonance frequency. Therefore, the secondary radiant force, which is much stronger at the resonance frequency, should play an important role in UCA-assisted drug delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Viscosity changes of riparian water controls diurnal fluctuations of stream-flow and DOC concentration

    Science.gov (United States)

    Schwab, Michael; Klaus, Julian; Pfister, Laurent; Weiler, Markus

    2015-04-01

    Diurnal fluctuations in stream-flow are commonly explained as being triggered by the daily evapotranspiration cycle in the riparian zone, leading to stream flow minima in the afternoon. While this trigger effect must necessarily be constrained by the extent of the growing season of vegetation, we here show evidence of daily stream flow maxima in the afternoon in a small headwater stream during the dormant season. We hypothesize that the afternoon maxima in stream flow are induced by viscosity changes of riparian water that is caused by diurnal temperature variations of the near surface groundwater in the riparian zone. The patterns were observed in the Weierbach headwater catchment in Luxembourg. The catchment is covering an area of 0.45 km2, is entirely covered by forest and is dominated by a schistous substratum. DOC concentration at the outlet of the catchment was measured with the field deployable UV-Vis spectrometer spectro::lyser (scan Messtechnik GmbH) with a high frequency of 15 minutes over several months. Discharge was measured with an ISCO 4120 Flow Logger. During the growing season, stream flow shows a frequently observed diurnal pattern with discharge minima in the afternoon. During the dormant season, a long dry period with daily air temperature amplitudes of around 10 ° C occurred in March and April 2014, with discharge maxima in the afternoon. The daily air temperature amplitude led to diurnal variations in the water temperature of the upper 10 cm of the riparian zone. Higher riparian water temperatures cause a decrease in water viscosity and according to the Hagen-Poiseuille equation, the volumetric flow rate is inversely proportional to viscosity. Based on the Hagen-Poiseuille equation and the viscosity changes of water, we calculated higher flow rates of near surface groundwater through the riparian zone into the stream in the afternoon which explains the stream flow maxima in the afternoon. With the start of the growing season, the viscosity

  19. Interaction of counter-streaming plasma flows in dipole magnetic field

    OpenAIRE

    Shaikhislamov, I F; Posukh, V G; Melekhov, A V; Prokopov, P A; Boyarintsev, E L; Zakharov, Yu P; Ponomarenko, A G

    2017-01-01

    Transient interaction of counter-streaming super-sonic plasma flows in dipole magnetic dipole is studied in laboratory experiment. First quasi-stationary flow is produced by teta-pinch and forms a magnetosphere around the magnetic dipole while laser beams focused at the surface of the dipole cover launch second explosive plasma expanding from inner dipole region outward. Laser plasma is energetic enough to disrupt magnetic field and to sweep through the background plasma for large distances. ...

  20. Assessing Ecological Flow Needs and Risks for Springs and Baseflow Streams With Growth and Climate Change

    Science.gov (United States)

    Springer, A. E.; Stevens, L. E.

    2008-12-01

    Ecological flow needs assessments are beginning to become an important part of regulated river management, but are more challenging for unregulated rivers. Water needs for ecosystems are greater than just consumptive use by riparian and aquatic vegetation and include the magnitude, frequency, duration and timing of flows and the depth and annual fluctuations of groundwater levels of baseflow supported streams. An ecological flow needs assessment was adapted and applied to an unregulated, baseflow dependent river in the arid to semi-arid Southwestern U.S. A separate process was developed to determine groundwater sources potentially at risk from climate, land management, or groundwater use changes in a large regional groundwater basin in the same semi-arid region. In 2007 and 2008, workshops with ecological, cultural, and physical experts from agencies, universities, tribes, and other organizations were convened. Flow-ecology response functions were developed with either conceptual or actual information for a baseflow dependent river, and scoring systems were developed to assign values to categories of risks to groundwater sources in a large groundwater basin. A reduction of baseflow to the river was predicted to lead to a decline in cottonwood and willow tree abundance, decreases in riparian forest diversity, and increases in non-native tree species, such as tamarisk. These types of forest vegetation changes would likely cause reductions or loss of some bird species. Loss of riffle habitat through declines in groundwater discharge and the associated river levels would likely lead to declines in native fish and amphibian species. A research agenda was developed to develop techniques to monitor, assess and hopefully better manage the aquifers supporting the baseflow dependent river to prevent potential threshold responses of the ecosystems. The scoring system for categories of risk was applied to four systems (aquifers, springs, standing water bodies, and streams) in

  1. Effect of β-PVDF Piezoelectric Transducers’ Positioning on the Acoustic Streaming Flows

    Directory of Open Access Journals (Sweden)

    Susana O. Catarino

    2014-09-01

    Full Text Available This paper reports the numerical and experimental analysis of the acoustic streaming effect in a fluidic domain. The actuation of a piezoelectric transducer generates acoustic waves that propagate to the fluids, generating pressure gradients that induce the flow. The number and positioning of the transducers affect the pressure gradients and, consequently, the resultant flow profile. Two actuation conditions were considered: (1 acoustic streaming generated by a 28 μm thick β-poly(vinylidene fluoride (β-PVDF piezoelectric transducer placed asymmetrically relative to the fluidic domain and (2 acoustic streaming generated by two 28 μm thick β-PVDF piezoelectric transducers placed perpendicularly to each other. The transducers were fixed to the lower left corner of a poly(methyl methacrylate (PMMAcuvette and were actuated with a 24 Vpp and 34.2 MHz sinusoidal voltage. The results show that the number of transducers and their positioning affects the shape and number of recirculation areas in the acoustic streaming flows. The obtained global flows show great potential for mixing and pumping, being an alternative to the previous geometries studied by the authors, namely, a single transducer placed symmetrically under a fluidic domain.

  2. Discrete simulations of spatio-temporal dynamics of small water bodies under varied stream flow discharges

    Science.gov (United States)

    Daya Sagar, B. S.

    2005-01-01

    Spatio-temporal patterns of small water bodies (SWBs) under the influence of temporally varied stream flow discharge are simulated in discrete space by employing geomorphologically realistic expansion and contraction transformations. Cascades of expansion-contraction are systematically performed by synchronizing them with stream flow discharge simulated via the logistic map. Templates with definite characteristic information are defined from stream flow discharge pattern as the basis to model the spatio-temporal organization of randomly situated surface water bodies of various sizes and shapes. These spatio-temporal patterns under varied parameters (λs) controlling stream flow discharge patterns are characterized by estimating their fractal dimensions. At various λs, nonlinear control parameters, we show the union of boundaries of water bodies that traverse the water body and non-water body spaces as geomorphic attractors. The computed fractal dimensions of these attractors are 1.58, 1.53, 1.78, 1.76, 1.84, and 1.90, respectively, at λs of 1, 2, 3, 3.46, 3.57, and 3.99. These values are in line with general visual observations.

  3. Prediction of the impacts of climate changes on the stream flow of ...

    African Journals Online (AJOL)

    Abstract. Soil and Water Assessment Tool, (SWAT) model was used to predict the impacts of Climate Change on Ajali River watershed, Aguobu-Umumba, Ezeagu, Enugu State, Nigeria. The model was first used to simulate stream flow using observed data. After model run, parameterization, sensitivity analysis, the monthly ...

  4. Climate and Land-Cover Change Impacts on Stream Flow in the Southwest U.S.

    Science.gov (United States)

    Vegetation change in arid and semi-arid climatic regions of the American West are a primary concern in sustaining key ecosystem services such as clean, reliable water sources for multiple uses. Land cover and climate change impacts on stream flow were investigated in a southeast ...

  5. Discrete simulations of spatio-temporal dynamics of small water bodies under varied stream flow discharges

    Directory of Open Access Journals (Sweden)

    B. S. Daya Sagar

    2005-01-01

    Full Text Available Spatio-temporal patterns of small water bodies (SWBs under the influence of temporally varied stream flow discharge are simulated in discrete space by employing geomorphologically realistic expansion and contraction transformations. Cascades of expansion-contraction are systematically performed by synchronizing them with stream flow discharge simulated via the logistic map. Templates with definite characteristic information are defined from stream flow discharge pattern as the basis to model the spatio-temporal organization of randomly situated surface water bodies of various sizes and shapes. These spatio-temporal patterns under varied parameters (λs controlling stream flow discharge patterns are characterized by estimating their fractal dimensions. At various λs, nonlinear control parameters, we show the union of boundaries of water bodies that traverse the water body and non-water body spaces as geomorphic attractors. The computed fractal dimensions of these attractors are 1.58, 1.53, 1.78, 1.76, 1.84, and 1.90, respectively, at λs of 1, 2, 3, 3.46, 3.57, and 3.99. These values are in line with general visual observations.

  6. Free-stream turbulence effects on the flow around an S809 wind turbine airfoil

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Nieves, Sheilla; Maldonado, Victor; Lebron, Jose [Rensselaer Polytechnic Institute, Troy, NY (United States); Kang, Hyung-Suk [United States Naval Academy, Annapolis, MD (United States); Meneveau, Charles [Johns Hopkins Univ., Baltimore, MD (United States); Castillo, Luciano [Texas Tech Univ., Lubbock, TX (United States)

    2012-07-01

    Two-dimensional Particle Image Velocimetry (2-D PIV) measurements were performed to study the effect of free-stream turbulence on the flow around a smooth and rough surface airfoil, specifically under stall conditions. A 0.25-m chord model with an S809 profile, common for horizontal-axis wind turbine applications, was tested at a wind tunnel speed of 10 m/s, resulting in Reynolds numbers based on the chord of Re{sub c} {approx} 182,000 and turbulence intensity levels of up to 6.14%. Results indicate that when the flow is fully attached, turbulence significantly decreases aerodynamic efficiency (from L/D {approx} 4.894 to L/D {approx} 0.908). On the contrary, when the flow is mostly stalled, the effect is reversed and aerodynamic performance is slightly improved (from L/D {approx} 1.696 to L/D {approx} 1.787). Analysis of the mean flow over the suction surface shows that, contrary to what is expected, free-stream turbulence is actually advancing separation, particularly when the turbulent scales in the free-stream are of the same order as the chord. This is a result of the complex dynamics between the boundary layer scales and the free-stream turbulence length scales when relatively high levels of active-grid generated turbulence are present. (orig.)

  7. Flowing water affects fish fast-starts: escape performance of the Hawaiian stream goby, Sicyopterus stimpsoni.

    Science.gov (United States)

    Diamond, Kelly M; Schoenfuss, Heiko L; Walker, Jeffrey A; Blob, Richard W

    2016-10-01

    Experimental measurements of escape performance in fishes have typically been conducted in still water; however, many fishes inhabit environments with flow that could impact escape behavior. We examined the influences of flow and predator attack direction on the escape behavior of fish, using juveniles of the amphidromous Hawaiian goby Sicyopterus stimpsoni In nature, these fish must escape ambush predation while moving through streams with high-velocity flow. We measured the escape performance of juvenile gobies while exposing them to a range of water velocities encountered in natural streams and stimulating fish from three different directions. Frequency of response across treatments indicated strong effects of flow conditions and attack direction. Juvenile S. stimpsoni had uniformly high response rates for attacks from a caudal direction (opposite flow); however, response rates for attacks from a cranial direction (matching flow) decreased dramatically as flow speed increased. Mechanical stimuli produced by predators attacking in the same direction as flow might be masked by the flow environment, impairing the ability of prey to detect attacks. Thus, the likelihood of successful escape performance in fishes can depend critically on environmental context. © 2016. Published by The Company of Biologists Ltd.

  8. Physical cleaning by bubbly streaming flow in an ultrasound field

    Science.gov (United States)

    Yamashita, Tatsuya; Ando, Keita

    2017-11-01

    Low-intensity ultrasonic cleaning with gas-supersaturated water is a promising method of physical cleaning without erosion; we are able to trigger cavitation bubble nucleation by weak ultrasound under gas supersaturation and thus clean material surfaces by mild bubble dynamics. Here, we perform particle image velocimetry (PIV) measurement of liquid flow and cavitation bubble translation in an ultrasonic cleaning bath driven at 28 kHz and then relate it to cleaning tests using glass slides at which silica particles are attached. The ultrasound pressure amplitude at the cleaning spot is set at 1.4 atm. We select the supersaturation level of dissolved oxygen (DO) as a parameter and control it by oxygen microbubble aeration. It follows from the PIV measurement that the liquid flow is enhanced by the cavitation bubble translation driven by acoustic radiation force; this trend becomes clearer when the bubbles appear more densely as the DO supersaturation increases. In the cleaning tests, the cleaned areas appear as straight streaks. This suggests that physical cleaning is achieved mainly by cavitation bubbles that translate in ultrasound fields.

  9. Residence-time framework for modeling multicomponent reactive transport in stream hyporheic zones

    Science.gov (United States)

    Painter, S. L.; Coon, E. T.; Brooks, S. C.

    2017-12-01

    Process-based models for transport and transformation of nutrients and contaminants in streams require tractable representations of solute exchange between the stream channel and biogeochemically active hyporheic zones. Residence-time based formulations provide an alternative to detailed three-dimensional simulations and have had good success in representing hyporheic exchange of non-reacting solutes. We extend the residence-time formulation for hyporheic transport to accommodate general multicomponent reactive transport. To that end, the integro-differential form of previous residence time models is replaced by an equivalent formulation based on a one-dimensional advection dispersion equation along the channel coupled at each channel location to a one-dimensional transport model in Lagrangian travel-time form. With the channel discretized for numerical solution, the associated Lagrangian model becomes a subgrid model representing an ensemble of streamlines that are diverted into the hyporheic zone before returning to the channel. In contrast to the previous integro-differential forms of the residence-time based models, the hyporheic flowpaths have semi-explicit spatial representation (parameterized by travel time), thus allowing coupling to general biogeochemical models. The approach has been implemented as a stream-corridor subgrid model in the open-source integrated surface/subsurface modeling software ATS. We use bedform-driven flow coupled to a biogeochemical model with explicit microbial biomass dynamics as an example to show that the subgrid representation is able to represent redox zonation in sediments and resulting effects on metal biogeochemical dynamics in a tractable manner that can be scaled to reach scales.

  10. Changes in Stream Flow and Their Relationships with Climatic Variations and Anthropogenic Activities in the Poyang Lake Basin, China

    Directory of Open Access Journals (Sweden)

    Chaojun Gu

    2016-12-01

    Full Text Available The Poyang Lake Basin has been suffering from severe water problems such as floods and droughts. This has led to great adverse impacts on local ecosystems and water resource utilization. It is therefore important to understand stream flow changes and their driving factors. In this paper, the dynamics of stream flow and precipitation in the Poyang Lake Basin between 1961 and 2012 were evaluated with the Mann–Kendall test, Theil–Sen approaches, Pettitt test, and Pearson’s correlation. Stream flow was measured at the outlets of five major tributaries of Poyang Lake, while precipitation was recorded by fourteen meteorological stations located within the Poyang Lake Basin. Results showed that annual stream flow of all tributaries and the precipitation over the study area had insignificant (P > 0.1 temporal trends and change points, while significant trends and shifts were found in monthly scale. Stream flow concentration indices (SCI at Waizhou, Meigang, and Wanjiabu stations showed significant (P < 0.05 decreasing trends with change points emerging in 1984 at Waizhou and 1978 at Wanjiabu, while there was no significant temporal trend and change point detected for the precipitation concentration indices (PCI. Correlation analysis indicated that area-average stream flow was closely related to area-average precipitation, but area-average SCI was insignificantly correlated with area-average PCI after change point (1984. El Niño/Southern Oscillation (ENSO had greater impacts on stream flow than other climate indices, and La Niña events played a more important role in stream flow changes than EI Niño. Human activities, particularly in terms of reservoir constructions, largely altered the intra-annual distribution of stream flow but its effects on the amount of stream flow were relatively low. Results of this study provided a useful reference to regional water resource management and the prevention of flood and drought disasters.

  11. Stream habitat analysis using the instream flow incremental methodology

    Science.gov (United States)

    Bovee, Ken D.; Lamb, Berton L.; Bartholow, John M.; Stalnaker, Clair B.; Taylor, Jonathan; Henriksen, Jim

    1998-01-01

    This document describes the Instream Flow Methodology in its entirety. This also is to serve as a comprehensive introductory textbook on IFIM for training courses as it contains the most complete and comprehensive description of IFIM in existence today. This should also serve as an official guide to IFIM in publication to counteract the misconceptions about the methodology that have pervaded the professional literature since the mid-1980's as this describes IFIM as it is envisioned by its developers. The document is aimed at the decisionmakers of management and allocation of natural resources in providing them an overview; and to those who design and implement studies to inform the decisionmakers. There should be enough background on model concepts, data requirements, calibration techniques, and quality assurance to help the technical user design and implement a cost-effective application of IFIM that will provide policy-relevant information. Some of the chapters deal with basic organization of IFIM, procedural sequence of applying IFIM starting with problem identification, study planning and implementation, and problem resolution.

  12. Viscous Potential Flow Analysis of Electroaerodynamic Instability of a Liquid Sheet Sprayed with an Air Stream

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar Awasthi

    2013-01-01

    Full Text Available The instability of a thin sheet of viscous and dielectric liquid moving in the same direction as an air stream in the presence of a uniform horizontal electric field has been carried out using viscous potential flow theory. It is observed that aerodynamic-enhanced instability occurs if the Weber number is much less than a critical value related to the ratio of the air and liquid stream velocities, viscosity ratio of two fluids, the electric field, and the dielectric constant values. Liquid viscosity has stabilizing effect in the stability analysis, while air viscosity has destabilizing effect.

  13. A numeric investigation of co-flowing liquid streams using the Lattice Boltzmann Method

    Science.gov (United States)

    Somogyi, Andy; Tagg, Randall

    2007-11-01

    We present a numerical investigation of co-flowing immiscible liquid streams using the Lattice Boltzmann Method (LBM) for multi component, dissimilar viscosity, immiscible fluid flow. When a liquid is injected into another immiscible liquid, the flow will eventually transition from jetting to dripping due to interfacial tension. Our implementation of LBM models the interfacial tension through a variety of techniques. Parallelization is also straightforward for both single and multi component models as only near local interaction is required. We compare the results of our numerical investigation using LBM to several recent physical experiments.

  14. Simulation of acoustic streaming by means of the finite-difference time-domain method

    DEFF Research Database (Denmark)

    Santillan, Arturo Orozco

    2012-01-01

    Numerical simulations of acoustic streaming generated by a standing wave in a narrow twodimensional cavity are presented. In this case, acoustic streaming arises from the viscous boundary layers set up at the surfaces of the walls. It is known that streaming vortices inside the boundary layer have...... directions of rotation that are opposite to those of the outer streaming vortices (Rayleigh streaming). The general objective of the work described in this paper has been to study the extent to which it is possible to simulate both the outer streaming vortices and the inner boundary layer vortices using...... the finite-difference time-domain method. To simplify the problem, thermal effects are not considered. The motivation of the described investigation has been the possibility of using the numerical method to study acoustic streaming, particularly under non-steady conditions. Results are discussed for channels...

  15. Face customization in a real-time digiTV stream

    Science.gov (United States)

    Lugmayr, Artur R.; Creutzburg, Reiner; Kalli, Seppo; Tsoumanis, Andreas

    2002-03-01

    The challenge in digital, interactive TV (digiTV) is to move the consumer from the refiguration state to the configuration state, where he can influence the story flow, the choice of characters and other narrative elements. Besides restructuring narrative and interactivity methodologies, one major task is content manipulation to provide the auditorium the ability to predefine actors that it wants to have in its virtual story universe. Current solutions in broadcasting video provide content as monolithic structure, composed of graphics, narration, special effects, etc. compressed into one high bit rate MPEG-2 stream. More personalized and interactive TV requires a contemporary approach to segment video data in real-time to customize contents. Our research work emphasizes techniques for interchanging faces/bodies against virtual anchors in real-time constrained broadcasted video streams. The aim of our research paper is to show and point out solutions for realizing real-time face and avatar customization. The major task for the broadcaster is metadata extraction by applying face detection/tracking/recognition algorithms, and transmission of the information to the client side. At the client side, our system shall provide the facility to pre-select virtual avatars stored in a local database, and synchronize movements and expressions with the current digiTV contents.

  16. Users Manual for the Geospatial Stream Flow Model (GeoSFM)

    Science.gov (United States)

    Artan, Guleid A.; Asante, Kwabena; Smith, Jodie; Pervez, Md Shahriar; Entenmann, Debbie; Verdin, James P.; Rowland, James

    2008-01-01

    The monitoring of wide-area hydrologic events requires the manipulation of large amounts of geospatial and time series data into concise information products that characterize the location and magnitude of the event. To perform these manipulations, scientists at the U.S. Geological Survey Center for Earth Resources Observation and Science (EROS), with the cooperation of the U.S. Agency for International Development, Office of Foreign Disaster Assistance (USAID/OFDA), have implemented a hydrologic modeling system. The system includes a data assimilation component to generate data for a Geospatial Stream Flow Model (GeoSFM) that can be run operationally to identify and map wide-area streamflow anomalies. GeoSFM integrates a geographical information system (GIS) for geospatial preprocessing and postprocessing tasks and hydrologic modeling routines implemented as dynamically linked libraries (DLLs) for time series manipulations. Model results include maps that depicting the status of streamflow and soil water conditions. This Users Manual provides step-by-step instructions for running the model and for downloading and processing the input data required for initial model parameterization and daily operation.

  17. Size-sensitive particle trajectories in three-dimensional micro-bubble acoustic streaming flows

    Science.gov (United States)

    Volk, Andreas; Rossi, Massimiliano; Hilgenfeldt, Sascha; Rallabandi, Bhargav; Kähler, Christian; Marin, Alvaro

    2015-11-01

    Oscillating microbubbles generate steady streaming flows with interesting features and promising applications for microparticle manipulation. The flow around oscillating semi-cylindrical bubbles has been typically assumed to be independent of the axial coordinate. However, it has been recently revealed that particle motion is strongly three-dimensional: Small tracer particles follow vortical trajectories with pronounced axial displacements near the bubble, weaving a toroidal stream-surface. A well-known consequence of bubble streaming flows is size-dependent particle migration, which can be exploited for sorting and trapping of microparticles in microfluidic devices. In this talk, we will show how the three-dimensional toroidal topology found for small tracer particles is modified as the particle size increases up to 1/3 of the bubble radius. Our results show size-sensitive particle positioning along the axis of the semi-cylindrical bubble. In order to analyze the three-dimensional sorting and trapping capabilities of the system, experiments with an imposed flow and polydisperse particle solutions are also shown.

  18. Lagrangian mass-flow investigations of inorganic contaminants in wastewater-impacted streams

    Science.gov (United States)

    Barber, L.B.; Antweiler, Ronald C.; Flynn, J.L.; Keefe, S.H.; Kolpin, D.W.; Roth, D.A.; Schnoebelen, D.J.; Taylor, Howard E.; Verplanck, P.L.

    2011-01-01

    Understanding the potential effects of increased reliance on wastewater treatment plant (WWTP) effluents to meet municipal, agricultural, and environmental flow requires an understanding of the complex chemical loading characteristics of the WWTPs and the assimilative capacity of receiving waters. Stream ecosystem effects are linked to proportions of WWTP effluent under low-flow conditions as well as the nature of the effluent chemical mixtures. This study quantifies the loading of 58 inorganic constituents (nutrients to rare earth elements) from WWTP discharges relative to upstream landscape-based sources. Stream assimilation capacity was evaluated by Lagrangian sampling, using flow velocities determined from tracer experiments to track the same parcel of water as it moved downstream. Boulder Creek, Colorado and Fourmile Creek, Iowa, representing two different geologic and hydrologic landscapes, were sampled under low-flow conditions in the summer and spring. One-half of the constituents had greater loads from the WWTP effluents than the upstream drainages, and once introduced into the streams, dilution was the predominant assimilation mechanism. Only ammonium and bismuth had significant decreases in mass load downstream from the WWTPs during all samplings. The link between hydrology and water chemistry inherent in Lagrangian sampling allows quantitative assessment of chemical fate across different landscapes. ?? 2011 American Chemical Society.

  19. An evaluation of the relations between flow regime components, stream characteristics, species traits and meta-demographic rates of warmwater stream fishes: Implications for aquatic resource management

    Science.gov (United States)

    Peterson, James T.; Shea, C.P.

    2015-01-01

    Fishery biologists are increasingly recognizing the importance of considering the dynamic nature of streams when developing streamflow policies. Such approaches require information on how flow regimes influence the physical environment and how those factors, in turn, affect species-specific demographic rates. A more cost-effective alternative could be the use of dynamic occupancy models to predict how species are likely to respond to changes in flow. To appraise the efficacy of this approach, we evaluated relative support for hypothesized effects of seasonal streamflow components, stream channel characteristics, and fish species traits on local extinction, colonization, and recruitment (meta-demographic rates) of stream fishes. We used 4 years of seasonal fish collection data from 23 streams to fit multistate, multiseason occupancy models for 42 fish species in the lower Flint River Basin, Georgia. Modelling results suggested that meta-demographic rates were influenced by streamflows, particularly short-term (10-day) flows. Flow effects on meta-demographic rates also varied with stream size, channel morphology, and fish species traits. Small-bodied species with generalized life-history characteristics were more resilient to flow variability than large-bodied species with specialized life-history characteristics. Using this approach, we simplified the modelling framework, thereby facilitating the development of dynamic, spatially explicit evaluations of the ecological consequences of water resource development activities over broad geographic areas. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  20. PRESEE: an MDL/MML algorithm to time-series stream segmenting.

    Science.gov (United States)

    Xu, Kaikuo; Jiang, Yexi; Tang, Mingjie; Yuan, Changan; Tang, Changjie

    2013-01-01

    Time-series stream is one of the most common data types in data mining field. It is prevalent in fields such as stock market, ecology, and medical care. Segmentation is a key step to accelerate the processing speed of time-series stream mining. Previous algorithms for segmenting mainly focused on the issue of ameliorating precision instead of paying much attention to the efficiency. Moreover, the performance of these algorithms depends heavily on parameters, which are hard for the users to set. In this paper, we propose PRESEE (parameter-free, real-time, and scalable time-series stream segmenting algorithm), which greatly improves the efficiency of time-series stream segmenting. PRESEE is based on both MDL (minimum description length) and MML (minimum message length) methods, which could segment the data automatically. To evaluate the performance of PRESEE, we conduct several experiments on time-series streams of different types and compare it with the state-of-art algorithm. The empirical results show that PRESEE is very efficient for real-time stream datasets by improving segmenting speed nearly ten times. The novelty of this algorithm is further demonstrated by the application of PRESEE in segmenting real-time stream datasets from ChinaFLUX sensor networks data stream.

  1. Groundwater, springs, and stream flow generation in an alpine meadow of a tropical glacierized catchment

    Science.gov (United States)

    Gordon, R.; Lautz, L. K.; McKenzie, J. M.; Mark, B. G.; Chavez, D.

    2013-12-01

    Melting tropical glaciers supply approximately half of dry season stream discharge in glacierized valleys of the Cordillera Blanca, Peru. The remainder of streamflow originates as groundwater stored in alpine meadows, moraines and talus slopes. A better understanding of the dynamics of alpine groundwater, including sources and contributions to streamflow, is important for making accurate estimates of glacial inputs to the hydrologic budget, and for our ability to make predictions about future water resources as glaciers retreat. Our field study, conducted during the dry season in the Llanganuco valley, focused on a 0.5-km2 alpine meadow complex at 4400 m elevation, which includes talus slopes, terminal moraines, and a debris fan. Two glacial lakes and springs throughout the complex feed a network of stream channels that flow across the meadow (~2 km total length). We combined tracer measurements of stream and spring discharge and groundwater-surface water exchange with synoptic sampling of water isotopic and geochemical composition, in order to characterize and quantify contributions to streamflow from different geomorphic features. Surface water inputs to the stream channels totaled 58 l/s, while the stream gained an additional 57 l/s from groundwater inputs. Water chemistry is primarily controlled by flowpath type (surface/subsurface) and length, as well as bedrock lithology, while stable water isotopic composition appears to be controlled by water source (glacial lake, meadow or deep groundwater). Stream water chemistry is most similar to meadow groundwater springs, but isotopic composition suggests that the majority of stream water, which issues from springs at the meadow/fan interface, is from the same glacial source as the up-gradient lake. Groundwater sampled from piezometers in confined meadow aquifers is unique in both chemistry and isotopic composition, but does not contribute a large percentage of stream water exiting this small meadow, as quantified by

  2. A Mechanism for Cytoplasmic Streaming: Kinesin-Driven Alignment of Microtubules and Fast Fluid Flows.

    Science.gov (United States)

    Monteith, Corey E; Brunner, Matthew E; Djagaeva, Inna; Bielecki, Anthony M; Deutsch, Joshua M; Saxton, William M

    2016-05-10

    The transport of cytoplasmic components can be profoundly affected by hydrodynamics. Cytoplasmic streaming in Drosophila oocytes offers a striking example. Forces on fluid from kinesin-1 are initially directed by a disordered meshwork of microtubules, generating minor slow cytoplasmic flows. Subsequently, to mix incoming nurse cell cytoplasm with ooplasm, a subcortical layer of microtubules forms parallel arrays that support long-range, fast flows. To analyze the streaming mechanism, we combined observations of microtubule and organelle motions with detailed mathematical modeling. In the fast state, microtubules tethered to the cortex form a thin subcortical layer and undergo correlated sinusoidal bending. Organelles moving in flows along the arrays show velocities that are slow near the cortex and fast on the inward side of the subcortical microtubule layer. Starting with fundamental physical principles suggested by qualitative hypotheses, and with published values for microtubule stiffness, kinesin velocity, and cytoplasmic viscosity, we developed a quantitative coupled hydrodynamic model for streaming. The fully detailed mathematical model and its simulations identify key variables that can shift the system between disordered (slow) and ordered (fast) states. Measurements of array curvature, wave period, and the effects of diminished kinesin velocity on flow rates, as well as prior observations on f-actin perturbation, support the model. This establishes a concrete mechanistic framework for the ooplasmic streaming process. The self-organizing fast phase is a result of viscous drag on kinesin-driven cargoes that mediates equal and opposite forces on cytoplasmic fluid and on microtubules whose minus ends are tethered to the cortex. Fluid moves toward plus ends and microtubules are forced backward toward their minus ends, resulting in buckling. Under certain conditions, the buckling microtubules self-organize into parallel bending arrays, guiding varying directions

  3. Method for Modeling High-Temporal-Resolution Stream Inflows in a Long-Term ParFlow.CLM Simulation

    Science.gov (United States)

    Miller, G. R.; Merket, C.

    2017-12-01

    Traditional hydrologic modeling has compartmentalized the water cycle into distinct components (e.g. rainfall-runoff, river routing, or groundwater flow models). An integrated, process-based modeling framework assesses two or more of these components simultaneously, reducing the error associated with approximated boundary conditions. One integrated model, ParFlow.CLM, offers the advantage of parallel computing, but it lacks any mechanism for incorporating time-varying streamflow as an upstream boundary condition. Here, we present a generalized method for applying transient streamflow at an upstream boundary in ParFlow.CLM. Downstream flow values are compared to predictions by traditional runoff and routing methods as implemented in HEC-HMS. Additionally, we define a model spin-up process which includes initialization of steady-state streamflow. The upstream inflow method was successfully tested on two domains - one synthetic tilted V catchment and an idealized small stream catchment in the Brazos River Basin. The stream in the idealized domain is gaged at the upstream and downstream boundaries. Both tests assumed a homogeneous subsurface so that the efficacy of the transient streamflow method could be evaluated with minimal complications by groundwater interactions. In the tilted V catchment, spin-up criteria were achieved within 6 model years. A 25 x 25 x 66 cell model grid was run at a computational efficiency of values early in the simulation.

  4. Curvilinear immersed-boundary method for simulating unsteady flows in shallow natural streams with arbitrarily complex obstacles

    Science.gov (United States)

    Kang, Seokkoo; Borazjani, Iman; Sotiropoulos, Fotis

    2008-11-01

    Unsteady 3D simulations of flows in natural streams is a challenging task due to the complexity of the bathymetry, the shallowness of the flow, and the presence of multiple nature- and man-made obstacles. This work is motivated by the need to develop a powerful numerical method for simulating such flows using coherent-structure-resolving turbulence models. We employ the curvilinear immersed boundary method of Ge and Sotiropoulos (Journal of Computational Physics, 2007) and address the critical issue of numerical efficiency in large aspect ratio computational domains and grids such as those encountered in long and shallow open channels. We show that the matrix-free Newton-Krylov method for solving the momentum equations coupled with an algebraic multigrid method with incomplete LU preconditioner for solving the Poisson equation yield a robust and efficient procedure for obtaining time-accurate solutions in such problems. We demonstrate the potential of the numerical approach by carrying out a direct numerical simulation of flow in a long and shallow meandering stream with multiple hydraulic structures.

  5. Gas stream analysis using voltage-current time differential operation of electrochemical sensors

    Science.gov (United States)

    Woo, Leta Yar-Li; Glass, Robert Scott; Fitzpatrick, Joseph Jay; Wang, Gangqiang; Henderson, Brett Tamatea; Lourdhusamy, Anthoniraj; Steppan, James John; Allmendinger, Klaus Karl

    2018-01-02

    A method for analysis of a gas stream. The method includes identifying an affected region of an affected waveform signal corresponding to at least one characteristic of the gas stream. The method also includes calculating a voltage-current time differential between the affected region of the affected waveform signal and a corresponding region of an original waveform signal. The affected region and the corresponding region of the waveform signals have a sensitivity specific to the at least one characteristic of the gas stream. The method also includes generating a value for the at least one characteristic of the gas stream based on the calculated voltage-current time differential.

  6. Using Streaming Analytics for Effective Real Time Network Visibility -

    Science.gov (United States)

    on in your network right now. Certainly the other thing that we talked about on the big data side was [inaudible] data. So now we'll drill into - so this is all the traffic from the internal network to the taking a streaming analytics approach to network traffic analysis. So we can go to the next - there we go

  7. Towards a characterization of real-time streaming systems

    NARCIS (Netherlands)

    Weffers-Albu, M.A.; Lukkien, J.J.; Stok, van der P.D.V.; Puaut, I.

    2005-01-01

    In this article we provide a model for the dynamic behavior of a single video streaming chain, by formulating a theorem describing the stable behavior. This stable behavior is characterized in terms of the elementary actions of the components in the chain, from which standard performance measures

  8. Open Source Initiative Powers Real-Time Data Streams

    Science.gov (United States)

    2014-01-01

    Under an SBIR contract with Dryden Flight Research Center, Creare Inc. developed a data collection tool called the Ring Buffered Network Bus. The technology has now been released under an open source license and is hosted by the Open Source DataTurbine Initiative. DataTurbine allows anyone to stream live data from sensors, labs, cameras, ocean buoys, cell phones, and more.

  9. Drainage basins, channels, and flow characteristics of selected streams in central Pennsylvania

    Science.gov (United States)

    Brush, Lucien M.

    1961-01-01

    The hydraulic, basin, and geologic characteristics of 16 selected streams in central Pennsylvania were measured for the purpose of studying the relations among these general characteristics and their process of development. The basic parameters which were measured include bankfull width and depth, channel slope, bed material size and shape, length of stream from drainage divide, and size of drainage area. The kinds of bedrock over which the streams flow were noted. In these streams the bankfull channel is filled by flows approximating the 2.3-year flood. By measuring the breadth and mean depth of the channel, it was possible to compute the bankfull mean velocity for each of the 119 sampling stations. These data were then used to compute the downstream changes in hydraulic geometry of the streams studied. This method has been called an indirect computation of the hydraulic geometry. The results obtained by the indirect method are similar to those of the direct method of other workers. The basins were studied by examining the relations of drainage area, discharge, and length of stream from drainage divide. For the streams investigated, excellent correlations were found to exist between drainage area and the 2.3-year flood, as well as between length of stream from the basin divide and drainage area. From these correlations it is possible to predict the discharge for the 2.3-year flood at any arbitrary point along the length of the stream. The long, intermediate, and short axes of pebbles sampled from the bed of the stream were recorded to study both size and sphericity changes along individual streams and among the streams studied. No systematic downstream changes in sphericity were found. Particle size changes are erratic and show no consistent relation to channel slope. Particle size decreases downstream in many streams but remains constant or increases in others. Addition of material by tributaries is one factor affecting particle size and another is the parent

  10. The effects of human land use on flow regime and water chemistry of headwater streams in the highlands of Chiapas

    Directory of Open Access Journals (Sweden)

    Castillo M.M.

    2013-03-01

    Full Text Available We studied the effects of land use changes on flow regime and water chemistry of headwater streams in the highlands of Chiapas, a region in southern Mexico that has experienced high rates of deforestation in the last decades. Samples for water chemistry were collected and discharge was measured between September 2007 and August 2008 at eight streams that differed in the land uses of their riparian and catchment areas, including streams draining protected forested areas. Streams with high forest cover (>70% in their catchments maintained flow through the year. Streams draining more disturbed catchments exhibited reduced or no flow for 4 − 6 months during the dry season. Nitrate concentrations were lower at streams draining forested catchments while highest concentrations were measured where conventional agriculture covered a high proportion of the catchment and riparian zone. Highest phosphorus concentrations occurred at the catchment where poultry manure was applied as fertilizer. Differences between forest streams and those draining disturbed areas were correlated with the proportion of forest and agriculture in the riparian zone. Variation in stream variables among sampling dates was lower at the forest sites than at the more disturbed study streams. Conversion of forest into agriculture and urban areas is affecting flow regime and increasing nutrient concentrations, although the magnitude of the impacts are influenced by the type of agricultural practices and the alteration of the riparian zone.

  11. Numerical and machine learning simulation of parametric distributions of groundwater residence time in streams and wells

    Science.gov (United States)

    Starn, J. J.; Belitz, K.; Carlson, C.

    2017-12-01

    Groundwater residence-time distributions (RTDs) are critical for assessing susceptibility of water resources to contamination. This novel approach for estimating regional RTDs was to first simulate groundwater flow using existing regional digital data sets in 13 intermediate size watersheds (each an average of 7,000 square kilometers) that are representative of a wide range of glacial systems. RTDs were simulated with particle tracking. We refer to these models as "general models" because they are based on regional, as opposed to site-specific, digital data. Parametric RTDs were created from particle RTDs by fitting 1- and 2-component Weibull, gamma, and inverse Gaussian distributions, thus reducing a large number of particle travel times to 3 to 7 parameters (shape, location, and scale for each component plus a mixing fraction) for each modeled area. The scale parameter of these distributions is related to the mean exponential age; the shape parameter controls departure from the ideal exponential distribution and is partly a function of interaction with bedrock and with drainage density. Given the flexible shape and mathematical similarity of these distributions, any of them are potentially a good fit to particle RTDs. The 1-component gamma distribution provided a good fit to basin-wide particle RTDs. RTDs at monitoring wells and streams often have more complicated shapes than basin-wide RTDs, caused in part by heterogeneity in the model, and generally require 2-component distributions. A machine learning model was trained on the RTD parameters using features derived from regionally available watershed characteristics such as recharge rate, material thickness, and stream density. RTDs appeared to vary systematically across the landscape in relation to watershed features. This relation was used to produce maps of useful metrics with respect to risk-based thresholds, such as the time to first exceedance, time to maximum concentration, time above the threshold

  12. Residence times and nitrate transport in ground water discharging to streams in the Chesapeake Bay Watershed

    Science.gov (United States)

    Lindsey, Bruce D.; Phillips, Scott; Donnelly, Colleen A.; Speiran, Gary K.; Plummer, Niel; Bohlke, John Karl; Focazio, Michael J.; Burton, William C.; Busenberg, Eurybiades

    2003-01-01

    One of the major water-quality problems in the Chesapeake Bay is an overabundance of nutrients from the streams and rivers that discharge to the Bay. Some of these nutrients are from nonpoint sources such as atmospheric deposition, agricultural manure and fertilizer, and septic systems. The effects of efforts to control nonpoint sources, however, can be difficult to quantify because of the lag time between changes at the land surface and the response in the base-flow (ground water) component of streams. To help resource managers understand the lag time between implementation of management practices and subsequent response in the nutrient concentrations in the base-flow component of streamflow, a study of ground-water discharge, residence time, and nitrate transport in springs throughout the Chesapeake Bay Watershed and in four smaller watersheds in selected hydrogeomorphic regions (HGMRs) was conducted. The four watersheds were in the Coastal Plain Uplands, Piedmont crystalline, Valley and Ridge carbonate, and Valley and Ridge siliciclastic HGMRs.A study of springs to estimate an apparent age of the ground water was based on analyses for concentrations of chlorofluorocarbons in water samples collected from 48 springs in the Chesapeake Bay Watershed. Results of the analysis indicate that median age for all the samples was 10 years, with the 25th percentile having an age of 7 years and the 75th percentile having an age of 13 years. Although the number of samples collected in each HGMR was limited, there did not appear to be distinct differences in the ages between the HGMRs. The ranges were similar between the major HGMRs above the Fall Line (modern to about 50 years), with only two HGMRs of small geographic extent (Piedmont carbonate and Mesozoic Lowland) having ranges of modern to about 10 years. The median values of all the HGMRs ranged from 7 to 11 years. Not enough samples were collected in the Coastal Plain for comparison. Spring samples showed slightly younger

  13. A review of lot streaming in a flow shop environment with makespan criteria

    Directory of Open Access Journals (Sweden)

    Pedro Gómez-Gasquet

    2013-07-01

    Full Text Available Purpose: This paper reviews current literature and contributes a set of findings that capture the current state-of-the-art of the topic of lot streaming in a flow-shop. Design/methodology/approach: A literature review to capture, classify and summarize the main body of knowledge on lot streaming in a flow-shop with makespan criteria and, translate this into a form that is readily accessible to researchers and practitioners in the more mainstream production scheduling community. Findings and Originality/value: The existing knowledge base is somewhat fragmented. This is a relatively unexplored topic within mainstream operations management research and one which could provide rich opportunities for further exploration. Originality/value: This paper sets out to review current literature, from an advanced production scheduling perspective, and contributes a set of findings that capture the current state-of-the-art of this topic.

  14. Turbulent Mixing of Primary and Secondary Flow Streams in a Rocket-Based Combined Cycle Engine

    Science.gov (United States)

    Cramer, J. M.; Greene, M. U.; Pal, S.; Santoro, R. J.; Turner, Jim (Technical Monitor)

    2002-01-01

    This viewgraph presentation gives an overview of the turbulent mixing of primary and secondary flow streams in a rocket-based combined cycle (RBCC) engine. A significant RBCC ejector mode database has been generated, detailing single and twin thruster configurations and global and local measurements. On-going analysis and correlation efforts include Marshall Space Flight Center computational fluid dynamics modeling and turbulent shear layer analysis. Potential follow-on activities include detailed measurements of air flow static pressure and velocity profiles, investigations into other thruster spacing configurations, performing a fundamental shear layer mixing study, and demonstrating single-shot Raman measurements.

  15. Real-time lossless compression of depth streams

    KAUST Repository

    Schneider, Jens

    2017-08-17

    Various examples are provided for lossless compression of data streams. In one example, a Z-lossless (ZLS) compression method includes generating compacted depth information by condensing information of a depth image and a compressed binary representation of the depth image using histogram compaction and decorrelating the compacted depth information to produce bitplane slicing of residuals by spatial prediction. In another example, an apparatus includes imaging circuitry that can capture one or more depth images and processing circuitry that can generate compacted depth information by condensing information of a captured depth image and a compressed binary representation of the captured depth image using histogram compaction; decorrelate the compacted depth information to produce bitplane slicing of residuals by spatial prediction; and generate an output stream based upon the bitplane slicing.

  16. Real-time lossless compression of depth streams

    KAUST Repository

    Schneider, Jens

    2017-01-01

    Various examples are provided for lossless compression of data streams. In one example, a Z-lossless (ZLS) compression method includes generating compacted depth information by condensing information of a depth image and a compressed binary representation of the depth image using histogram compaction and decorrelating the compacted depth information to produce bitplane slicing of residuals by spatial prediction. In another example, an apparatus includes imaging circuitry that can capture one or more depth images and processing circuitry that can generate compacted depth information by condensing information of a captured depth image and a compressed binary representation of the captured depth image using histogram compaction; decorrelate the compacted depth information to produce bitplane slicing of residuals by spatial prediction; and generate an output stream based upon the bitplane slicing.

  17. Overcoming equifinality: Leveraging long time series for stream metabolism estimation

    Science.gov (United States)

    Appling, Alison; Hall, Robert O.; Yackulic, Charles B.; Arroita, Maite

    2018-01-01

    The foundational ecosystem processes of gross primary production (GPP) and ecosystem respiration (ER) cannot be measured directly but can be modeled in aquatic ecosystems from subdaily patterns of oxygen (O2) concentrations. Because rivers and streams constantly exchange O2 with the atmosphere, models must either use empirical estimates of the gas exchange rate coefficient (K600) or solve for all three parameters (GPP, ER, and K600) simultaneously. Empirical measurements of K600 require substantial field work and can still be inaccurate. Three-parameter models have suffered from equifinality, where good fits to O2 data are achieved by many different parameter values, some unrealistic. We developed a new three-parameter, multiday model that ensures similar values for K600 among days with similar physical conditions (e.g., discharge). Our new model overcomes the equifinality problem by (1) flexibly relating K600 to discharge while permitting moderate daily deviations and (2) avoiding the oft-violated assumption that residuals in O2 predictions are uncorrelated. We implemented this hierarchical state-space model and several competitor models in an open-source R package, streamMetabolizer. We then tested the models against both simulated and field data. Our new model reduces error by as much as 70% in daily estimates of K600, GPP, and ER. Further, accuracy benefits of multiday data sets require as few as 3 days of data. This approach facilitates more accurate metabolism estimates for more streams and days, enabling researchers to better quantify carbon fluxes, compare streams by their metabolic regimes, and investigate controls on aquatic activity.

  18. Predicting the natural flow regime: Models for assessing hydrological alteration in streams

    Science.gov (United States)

    Carlisle, D.M.; Falcone, J.; Wolock, D.M.; Meador, M.R.; Norris, R.H.

    2009-01-01

    Understanding the extent to which natural streamflow characteristics have been altered is an important consideration for ecological assessments of streams. Assessing hydrologic condition requires that we quantify the attributes of the flow regime that would be expected in the absence of anthropogenic modifications. The objective of this study was to evaluate whether selected streamflow characteristics could be predicted at regional and national scales using geospatial data. Long-term, gaged river basins distributed throughout the contiguous US that had streamflow characteristics representing least disturbed or near pristine conditions were identified. Thirteen metrics of the magnitude, frequency, duration, timing and rate of change of streamflow were calculated using a 20-50 year period of record for each site. We used random forests (RF), a robust statistical modelling approach, to develop models that predicted the value for each streamflow metric using natural watershed characteristics. We compared the performance (i.e. bias and precision) of national- and regional-scale predictive models to that of models based on landscape classifications, including major river basins, ecoregions and hydrologic landscape regions (HLR). For all hydrologic metrics, landscape stratification models produced estimates that were less biased and more precise than a null model that accounted for no natural variability. Predictive models at the national and regional scale performed equally well, and substantially improved predictions of all hydrologic metrics relative to landscape stratification models. Prediction error rates ranged from 15 to 40%, but were 25% for most metrics. We selected three gaged, non-reference sites to illustrate how predictive models could be used to assess hydrologic condition. These examples show how the models accurately estimate predisturbance conditions and are sensitive to changes in streamflow variability associated with long-term land-use change. We also

  19. 5G Terminals with Multi-Streaming Features for Real-Time Mobile Broadband Applications

    Directory of Open Access Journals (Sweden)

    T. Shuminoski

    2017-06-01

    Full Text Available In this paper we present a novel QoS framework on the network layer for 5G terminals with vertical multi-homing and multi-streaming capabilities by using radio networks aggregation. The proposed framework is leading to high performance utility networks with QoS provisioning for real-time multimedia services by achieving low packet delays, stochastic queuing network stability and highest mobile broadband capabilities i.e. bitrates. The proposed QoS algorithm is implemented within the mobile terminals on one side, and in dedicated proxy servers on mobile core network side. It is based on Lyapunov optimization techniques and it is targeted to handle simultaneously multiple multimedia service flows via multiple radio network interfaces in parallel.

  20. Steady streaming: A key mixing mechanism in low-Reynolds-number acinar flows

    Science.gov (United States)

    Kumar, Haribalan; Tawhai, Merryn H.; Hoffman, Eric A.; Lin, Ching-Long

    2011-01-01

    Study of mixing is important in understanding transport of submicron sized particles in the acinar region of the lung. In this article, we investigate transport in view of advective mixing utilizing Lagrangian particle tracking techniques: tracer advection, stretch rate and dispersion analysis. The phenomenon of steady streaming in an oscillatory flow is found to hold the key to the origin of kinematic mixing in the alveolus, the alveolar mouth and the alveolated duct. This mechanism provides the common route to folding of material lines and surfaces in any region of the acinar flow, and has no bearing on whether the geometry is expanding or if flow separates within the cavity or not. All analyses consistently indicate a significant decrease in mixing with decreasing Reynolds number (Re). For a given Re, dispersion is found to increase with degree of alveolation, indicating that geometry effects are important. These effects of Re and geometry can also be explained by the streaming mechanism. Based on flow conditions and resultant convective mixing measures, we conclude that significant convective mixing in the duct and within an alveolus could originate only in the first few generations of the acinar tree as a result of nonzero inertia, flow asymmetry, and large Keulegan–Carpenter (KC) number. PMID:21580803

  1. Importance of neutral processes varies in time and space: Evidence from dryland stream ecosystems.

    Directory of Open Access Journals (Sweden)

    Xiaoli Dong

    Full Text Available Many ecosystems experience strong temporal variability in environmental conditions; yet, a clear picture of how niche and neutral processes operate to determine community assembly in temporally variable systems remains elusive. In this study, we constructed neutral metacommunity models to assess the relative importance of neutral processes in a spatially and temporally variable ecosystem. We analyzed macroinvertebrate community data spanning multiple seasons and years from 20 sites in a Sonoran Desert river network in Arizona. The model goodness-of-fit was used to infer the importance of neutral processes. Averaging over eight stream flow conditions across three years, we found that neutral processes were more important in perennial streams than in non-perennial streams (intermittent and ephemeral streams. Averaging across perennial and non-perennial streams, we found that neutral processes were more important during very high flow and in low flow periods; whereas, at very low flows, the relative importance of neutral processes varied greatly. These findings were robust to the choice of model parameter values. Our study suggested that the net effect of disturbance on the relative importance of niche and neutral processes in community assembly varies non-monotonically with the severity of disturbance. In contrast to the prevailing view that disturbance promotes niche processes, we found that neutral processes could become more important when the severity of disturbance is beyond a certain threshold such that all organisms are adversely affected regardless of their biological traits and strategies.

  2. Regional Relations in Bankfull Channel Characteristics determined from flow measurements at selected stream-gaging stations in West Virginia, 1911-2002

    Science.gov (United States)

    Messinger, Terence; Wiley, Jeffrey B.

    2004-01-01

    Three bankfull channel characteristics?cross-sectional area, width, and depth?were significantly correlated with drainage area in regression equations developed for two regions in West Virginia. Channel characteristics were determined from analysis of flow measurements made at 74 U.S. Geological Survey stream-gaging stations at flows between 0.5 and 5.0 times bankfull flow between 1911 and 2002. Graphical and regression analysis were used to delineate an 'Eastern Region' and a 'Western Region,' which were separated by the boundary between the Appalachian Plateaus and Valley and Ridge Physiographic Provinces. Streams that drained parts of both provinces had channel characteristics typical of the Eastern Region, and were grouped with it. Standard error for the six regression equations, three for each region, ranged between 8.7 and 16 percent. Cross-sectional area and depth were greater relative to drainage area for the Western Region than they were for the Eastern Region. Regression equations were defined for streams draining between 46.5 and 1,619 square miles for the Eastern Region, and between 2.78 and 1,354 square miles for the Western Region. Stream-gaging stations with two or more cross sections where flow had been measured at flows between 0.5 and 5.0 times the 1.5-year flow showed poor replication of channel characteristics compared to the 95-percent confidence intervals of the regression, suggesting that within-reach variability for the stream-gaging stations may be substantial. A disproportionate number of the selected stream-gaging stations were on large (drainage area greater than 100 square miles) streams in the central highlands of West Virginia, and only one stream-gaging station that met data-quality criteria was available to represent the region within about 50 miles of the Ohio River north of Parkersburg, West Virginia. Many of the cross sections were at bridges, which can change channel shape. Although the data discussed in this report may not be

  3. Effects of flow intermittency and pharmaceutical exposure on the structure and metabolism of stream biofilms.

    Science.gov (United States)

    Corcoll, Natàlia; Casellas, Maria; Huerta, Belinda; Guasch, Helena; Acuña, Vicenç; Rodríguez-Mozaz, Sara; Serra-Compte, Albert; Barceló, Damià; Sabater, Sergi

    2015-01-15

    Increasing concentrations of pharmaceutical compounds occur in many rivers, but their environmental risk remains poorly studied in stream biofilms. Flow intermittency shapes the structure and functions of ecosystems, and may enhance their sensitivity to toxicants. This study evaluates the effects of a long-term exposure of biofilm communities to a mixture of pharmaceutical compounds at environmental concentrations on biofilm bioaccumulation capacity, the structure and metabolic processes of algae and bacteria communities, and how their potential effects were enhanced or not by the occurrence of flow intermittency. To assess the interaction between those two stressors, an experiment with artificial streams was performed. Stream biofilms were exposed to a mixture of pharmaceuticals, as well as to a short period of flow intermittency. Results indicate that biofilms were negatively affected by pharmaceuticals. The algal biomass and taxa richness decreased and unicellular green algae relatively increased. The structure of the bacterial (based on denaturing gradient gel electrophoresis of amplified 16S rRNA genes) changed and showed a reduction of the operational taxonomic units (OTUs) richness. Exposed biofilms showed higher rates of metabolic processes, such as primary production and community respiration, attributed to pharmaceuticals stimulated an increase of green algae and heterotrophs, respectively. Flow intermittency modulated the effects of chemicals on natural communities. The algal community became more sensitive to short-term exposure of pharmaceuticals (lower EC50 value) when exposed to water intermittency, indicating cumulative effects between the two assessed stressors. In contrast to algae, the bacterial community became less sensitive to short-term exposure of pharmaceuticals (higher EC50) when exposed to water intermittency, indicating co-tolerance phenomena. According to the observed effects, the environmental risk of pharmaceuticals in nature is high

  4. Scalable Video Streaming Adaptive to Time-Varying IEEE 802.11 MAC Parameters

    Science.gov (United States)

    Lee, Kyung-Jun; Suh, Doug-Young; Park, Gwang-Hoon; Huh, Jae-Doo

    This letter proposes a QoS control method for video streaming service over wireless networks. Based on statistical analysis, the time-varying MAC parameters highly related to channel condition are selected to predict available bitrate. Adaptive bitrate control of scalably-encoded video guarantees continuity in streaming service even if the channel condition changes abruptly.

  5. Effect of morphology and discharge on hyporheic exchange flows in two small streams in the Cascade Mountains of Oregon, USA.

    Science.gov (United States)

    Steven M. Wondzell

    2006-01-01

    Stream-tracer injections were used to examine the effect of channel morphology and changing stream discharge on hyporheic exchange flows. Direct observations were made from well networks to follow tracer movement through the hyporheic zone. The reach-integrated influence of hyporheic exchange was evaluated using the transient storage model (TSM) OTIS-P. Transient...

  6. Morphological divergence and flow-induced phenotypic plasticity in a native fish from anthropogenically altered stream habitats.

    Science.gov (United States)

    Franssen, Nathan R; Stewart, Laura K; Schaefer, Jacob F

    2013-11-01

    Understanding population-level responses to human-induced changes to habitats can elucidate the evolutionary consequences of rapid habitat alteration. Reservoirs constructed on streams expose stream fishes to novel selective pressures in these habitats. Assessing the drivers of trait divergence facilitated by these habitats will help identify evolutionary and ecological consequences of reservoir habitats. We tested for morphological divergence in a stream fish that occupies both stream and reservoir habitats. To assess contributions of genetic-level differences and phenotypic plasticity induced by flow variation, we spawned and reared individuals from both habitats types in flow and no flow conditions. Body shape significantly and consistently diverged in reservoir habitats compared with streams; individuals from reservoirs were shallower bodied with smaller heads compared with individuals from streams. Significant population-level differences in morphology persisted in offspring but morphological variation compared with field-collected individuals was limited to the head region. Populations demonstrated dissimilar flow-induced phenotypic plasticity when reared under flow, but phenotypic plasticity in response to flow variation was an unlikely explanation for observed phenotypic divergence in the field. Our results, together with previous investigations, suggest the environmental conditions currently thought to drive morphological change in reservoirs (i.e., predation and flow regimes) may not be the sole drivers of phenotypic change.

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

    Science.gov (United States)

    Sebok, Eva; Engesgaard, Peter; Duque, Carlos

    2017-08-24

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

  8. Development of a stream-aquifer numerical flow model to assess river water management under water scarcity in a Mediterranean basin.

    Science.gov (United States)

    Mas-Pla, Josep; Font, Eva; Astui, Oihane; Menció, Anna; Rodríguez-Florit, Agustí; Folch, Albert; Brusi, David; Pérez-Paricio, Alfredo

    2012-12-01

    Stream flow, as a part of a basin hydrological cycle, will be sensible to water scarcity as a result of climate change. Stream vulnerability should then be evaluated as a key component of the basin water budget. Numerical flow modeling has been applied to an alluvial formation in a small mountain basin to evaluate the stream-aquifer relationship under these future scenarios. The Arbúcies River basin (116 km(2)) is located in the Catalan Inner Basins (NE Spain) and its lower reach, which is related to an alluvial aquifer, usually becomes dry during the summer period. This study seeks to determine the origin of such discharge losses whether from natural stream leakage and/or induced capture due to groundwater withdrawal. Our goal is also investigating how discharge variations from the basin headwaters, representing potential effects of climate change, may affect stream flow, aquifer recharge, and finally environmental preservation and human supply. A numerical flow model of the alluvial aquifer, based on MODFLOW and especially in the STREAM routine, reproduced the flow system after the usual calibration. Results indicate that, in the average, stream flow provides more than 50% of the water inputs to the alluvial aquifer, being responsible for the amount of stored water resources and for satisfying groundwater exploitation for human needs. Detailed simulations using daily time-steps permit setting threshold values for the stream flow entering at the beginning of the studied area so surface discharge is maintained along the whole watercourse and ecological flow requirements are satisfied as well. The effects of predicted rainfall and temperature variations on the Arbúcies River alluvial aquifer water balance are also discussed from the outcomes of the simulations. Finally, model results indicate the relevance of headwater discharge management under future climate scenarios to preserve downstream hydrological processes. They also point out that small mountain basins

  9. Linking stream flow and groundwater to avian habitat in a desert riparian system.

    Science.gov (United States)

    Merritt, David M; Bateman, Heather L

    2012-10-01

    Increasing human populations have resulted in aggressive water development in arid regions. This development typically results in altered stream flow regimes, reduced annual flow volumes, changes in fluvial disturbance regimes, changes in groundwater levels, and subsequent shifts in ecological patterns and processes. Balancing human demands for water with environmental requirements to maintain functioning ecosystems requires quantitative linkages between water in streams and ecosystem attributes. Streams in the Sonoran Desert provide important habitat for vertebrate species, including resident and migratory birds. Habitat structure, food, and nest-building materials, which are concentrated in riparian areas, are provided directly or indirectly by vegetation. We measured riparian vegetation, groundwater and surface water, habitat structure, and bird occurrence along Cherry Creek, a perennial tributary of the Salt River in central Arizona, USA. The purpose of this work was to develop an integrated model of groundwater-vegetation-habitat structure and bird occurrence by: (1) characterizing structural and provisioning attributes of riparian vegetation through developing a bird habitat index (BHI), (2) validating the utility of our BHI through relating it to measured bird community composition, (3) determining the riparian plant species that best explain the variability in BHI, (4) developing predictive models that link important riparian species to fluvial disturbance and groundwater availability along an arid-land stream, and (5) simulating the effects of changes in flow regime and groundwater levels and determining their consequences for riparian bird communities. Riparian forest and shrubland vegetation cover types were correctly classified in 83% of observations as a function of fluvial disturbance and depth to water table. Groundwater decline and decreased magnitude of fluvial disturbance caused significant shifts in riparian cover types from riparian forest to

  10. Time course of auditory streaming: Do CI users differ from normal-hearing listeners?

    Directory of Open Access Journals (Sweden)

    Martin eBöckmann-Barthel

    2014-07-01

    Full Text Available In a complex acoustical environment with multiple sound sources the auditory system uses streaming as a tool to organize the incoming sounds in one or more streams depending on the stimulus parameters. Streaming is commonly studied by alternating sequences of signals. These are often tones with different frequencies. The present study investigates stream segregation in cochlear implant (CI users, where hearing is restored by electrical stimulation of the auditory nerve. CI users listened to 30-s long sequences of alternating A and B harmonic complexes at four different fundamental frequency separations, ranging from 2 to 14 semitones. They had to indicate as promptly as possible after sequence onset, if they perceived one stream or two streams and, in addition, any changes of the percept throughout the rest of the sequence. The conventional view is that the initial percept is always that of a single stream which may after some time change to a percept of two streams. This general build-up hypothesis has recently been challenged on the basis of a new analysis of data of normal-hearing listeners which showed a build-up response only for an intermediate frequency separation. Using the same experimental paradigm and analysis, the present study found that the results of CI users agree with those of the normal-hearing listeners: (i the probability of the first decision to be a one-stream percept decreased and that of a two-stream percept increased as Δf increased, and (ii a build-up was only found for 6 semitones. Only the time elapsed before the listeners made their first decision of the percept was prolonged as compared to normal-hearing listeners. The similarity in the data of the CI user and the normal-hearing listeners indicates that the quality of stream formation is similar in these groups of listeners.

  11. An Assessment of Mean Areal Precipitation Methods on Simulated Stream Flow: A SWAT Model Performance Assessment

    Directory of Open Access Journals (Sweden)

    Sean Zeiger

    2017-06-01

    Full Text Available Accurate mean areal precipitation (MAP estimates are essential input forcings for hydrologic models. However, the selection of the most accurate method to estimate MAP can be daunting because there are numerous methods to choose from (e.g., proximate gauge, direct weighted average, surface-fitting, and remotely sensed methods. Multiple methods (n = 19 were used to estimate MAP with precipitation data from 11 distributed monitoring sites, and 4 remotely sensed data sets. Each method was validated against the hydrologic model simulated stream flow using the Soil and Water Assessment Tool (SWAT. SWAT was validated using a split-site method and the observed stream flow data from five nested-scale gauging sites in a mixed-land-use watershed of the central USA. Cross-validation results showed the error associated with surface-fitting and remotely sensed methods ranging from −4.5 to −5.1%, and −9.8 to −14.7%, respectively. Split-site validation results showed the percent bias (PBIAS values that ranged from −4.5 to −160%. Second order polynomial functions especially overestimated precipitation and subsequent stream flow simulations (PBIAS = −160 in the headwaters. The results indicated that using an inverse-distance weighted, linear polynomial interpolation or multiquadric function method to estimate MAP may improve SWAT model simulations. Collectively, the results highlight the importance of spatially distributed observed hydroclimate data for precipitation and subsequent steam flow estimations. The MAP methods demonstrated in the current work can be used to reduce hydrologic model uncertainty caused by watershed physiographic differences.

  12. A continuous-flow system for measuring in vitro oxygen and nitrogen metabolism in separated stream communities

    DEFF Research Database (Denmark)

    Prahl, C.; Jeppesen, E.; Sand-Jensen, Kaj

    1991-01-01

    on the stream bank, consists of several macrophyte and sediment chambers equipped with a double-flow system that ensures an internal water velocity close to that in the stream and which, by continuously renewing the water, mimics diel fluctuation in stream temperature and water chemistry. Water temperature...... production and dark respiration occurred at similar rates (6-7g O2 m-2 day-1), net balance being about zero. Inorganic nitrogen was consumed both by the sediment and to a greater extent by the macrophytes, the diel average consumption being 1g N m-2 day-1. 3. The sum of the activity in the macrophyte...... and sediment chambers corresponded to the overall activity of the stream section as determined by upstream/downstream mass balance. This indicates that the results obtained with the continuous-flow chambers realistically describe the oxygen and the nitrogen metabolism of the stream....

  13. Patterns in stream longitudinal profiles and implications for hyporheic exchange flow at the H.J. Andrews Experimental Forest, Oregon, USA.

    Science.gov (United States)

    Justin K. Anderson; Steven M. Wondzell; Michael N. Gooseff; Roy. Haggerty

    2005-01-01

    There is a need to identify measurable characteristics of stream channel morphology that vary predictably throughout stream networks and that influence patterns of hyporheic exchange flow in mountain streams. In this paper we characterize stream longitudinal profiles according to channel unit spacing and the concavity of the water surface profile. We demonstrate that...

  14. Theoretical study of time-dependent, ultrasound-induced acoustic streaming in microchannels

    DEFF Research Database (Denmark)

    Muller, Peter Barkholt; Bruus, Henrik

    2015-01-01

    Based on first- and second-order perturbation theory, we present a numerical study of the temporal buildup and decay of unsteady acoustic fields and acoustic streaming flows actuated by vibrating walls in the transverse cross-sectional plane of a long straight microchannel under adiabatic...

  15. Nonlinear forecasting of stream flows using a chaotic approach and artificial neural networks

    Directory of Open Access Journals (Sweden)

    Hakan Tongal

    2013-07-01

    Full Text Available This paper evaluates the forecasting performance of two nonlinear models, k-nearest neighbor (kNN and feed-forward neural networks (FFNN, using stream flow data of the Kızılırmak River, the longest river in Turkey. For the kNN model, the required parameters are delay time, number of nearest neigh- bors and embedding dimension. The optimal delay time was obtained with the mutual information function; the number of nearest neighbors was obtained with the optimization process that minimi- zes RMSE as a function of the neighbor number and the embedding dimension was obtained with the correlation dimension method. The correlation dimension of the Kızılırmak River was d = 2.702, which was used in forming the input structure of the FFNN. The nearest integer above the correlation dimension (i.e., 3 provided the minimal number of required variables to characterize the system, and the maximum number of required variables was obtained with the nearest integer above the value 2d + 1 (Takens, 1981 (i.e., 7. Two FFNN models were developed that incorporate 3 and 7 lagged discharge values and the predicted performance compared to that of the kNN model. The results showed that the kNN model was superior to the FFNN model in stream flow forecasting. However, as a result from the kNN model structure, the model failed in the prediction of peak values. Additionally, it was found that the correlation dimension (if it existed could successfully be used in time series where the determina- tion of the input structure is difficult because of high inter-dependency, as in stream flow time series.  Resumen Este trabajo evalúa el desempeño de pronóstico de dos modelos no lineares, de método de clasificación no paramétrico kNN y de redes neuronales con alimentación avanzada (FNNN, usando datos de flujo del río Kizilirmak, el mayor de Turquía. Para el modelo kNN, los parámetros requeridos son tiempo de retraso, número de vecindarios cercanos y dimensión de

  16. VEGETATION BEHAVIOR AND ITS HABITAT REGION AGAINST FLOOD FLOW IN URBAN STREAMS

    Directory of Open Access Journals (Sweden)

    IL-KI CHOI

    2013-06-01

    Full Text Available Hydraulic effects on the vegetation behavior and on its habitat region against flood flow in the urban streams were analysed in this paper. Vegetation behavior was classified into stable, recovered, damaged and swept away stages. Criteria between recovered and damaged status were determined by the bending angle of the aquatic plants. Aquatic plants whose bending angle is lower than 30~50 degree is recovered, but they were damaged and cannot be recovered when the bending angle is higher than 30~50 degree. Phragmites japonica was inhabited in the hydraulic condition of high Froude number which shows that it was inhabited in the upstream reaches. Phragmites communis was inhabited in the relatively low Froude number compared with Phragmites japonica. This shows that it was inhabited in the downstream reaches. Persicaria blumei was found in the relatively wide range of flow velocity and flow depth, which shows that it was inhabited in the middle and downstream reaches. Criterion on the vegetation behavior of Persicaria thunbergii was not clear, which implies that it may be affected by the flow turbulence rather than flow velocity and flow depth.

  17. Testing a community water supply well located near a stream for susceptibility to stream contamination and low-flows.

    Science.gov (United States)

    Stewart-Maddox, N. S.; Tysor, E. H.; Swanson, J.; Degon, A.; Howard, J.; Tsinnajinnie, L.; Frisbee, M. D.; Wilson, J. L.; Newman, B. D.

    2014-12-01

    A community well is the primary water supply to the town of El Rito. This small rural town in is located in a semi-arid, mountainous portion of northern New Mexico where water is scarce. The well is 72 meters from a nearby intermittent stream. Initial tritium sampling suggests a groundwater connection between the stream and well. The community is concerned with the sustainability and future quality of the well water. If this well is as tightly connected to the stream as the tritium data suggests, then the well is potentially at risk due to upstream contamination and the impacts of extended drought. To examine this, we observed the well over a two-week period performing pump and recovery tests, electrical resistivity surveys, and physical observations of the nearby stream. We also collected general chemistry, stable isotope and radon samples from the well and stream. Despite the large well diameter, our pump test data exhibited behavior similar to a Theis curve, but the rate of drawdown decreased below the Theis curve late in the test. This decrease suggests that the aquifer is being recharged, possibly through delayed yield, upwelling of groundwater, or from the stream. The delayed yield hypothesis is supported by our electrical resistivity surveys, which shows very little change in the saturated zone over the course of the pump test, and by low values of pump-test estimated aquifer storativity. Observations of the nearby stream showed no change in stream-water level throughout the pump test. Together this data suggests that the interaction between the stream and the well is low, but recharge could be occurring through other mechanisms such as delayed yield. Additional pump tests of longer duration are required to determine the exact nature of the aquifer and its communication with the well.

  18. Laboratory study on streaming potential for exploring underground water flow; Shitsunai jikken ni yoru ryudo den`i wo mochiita mizu michi tansa no kanosei no kento

    Energy Technology Data Exchange (ETDEWEB)

    Sato, H; Shima, H [Oyo Corp., Tokyo (Japan)

    1997-05-27

    To investigate a possibility of exploration of underground water flow as well as to grasp the underground fluid flow by measuring streaming potential at the ground surface, some experiments were conducted using a model unit by considering the difference of permeability. For this experimental unit, water is driven by adding head difference between the polyethylene vessel filled with water and the experimental water tank. The size of water tank is 350{times}160 mm with a height of 160 mm. Twenty platinum electrodes are set on the cover of water tank. Toyoura standard sand and Kanto loam were used for the experiments. For the experiments, fluid was injected in various combined models by considering the permeability, to measure the streaming potential. As a result, it was explained by the streaming potential that the fluid flows in a form of laminar flow in the experimental water tank, and that the movement of fluid in the Kanto loam is quite slow. It was also confirmed that the streaming potential method is an effective technique for grasping the movement of fluid. 3 refs., 8 figs.

  19. Fractionating power and outlet stream polydispersity in asymmetrical flow field-flow fractionation. Part I: isocratic operation.

    Science.gov (United States)

    Williams, P Stephen

    2016-05-01

    Asymmetrical flow field-flow fractionation (As-FlFFF) has become the most commonly used of the field-flow fractionation techniques. However, because of the interdependence of the channel flow and the cross flow through the accumulation wall, it is the most difficult of the techniques to optimize, particularly for programmed cross flow operation. For the analysis of polydisperse samples, the optimization should ideally be guided by the predicted fractionating power. Many experimentalists, however, neglect fractionating power and rely on light scattering detection simply to confirm apparent selectivity across the breadth of the eluted peak. The size information returned by the light scattering software is assumed to dispense with any reliance on theory to predict retention, and any departure of theoretical predictions from experimental observations is therefore considered of no importance. Separation depends on efficiency as well as selectivity, however, and efficiency can be a strong function of retention. The fractionation of a polydisperse sample by field-flow fractionation never provides a perfectly separated series of monodisperse fractions at the channel outlet. The outlet stream has some residual polydispersity, and it will be shown in this manuscript that the residual polydispersity is inversely related to the fractionating power. Due to the strong dependence of light scattering intensity and its angular distribution on the size of the scattering species, the outlet polydispersity must be minimized if reliable size data are to be obtained from the light scattering detector signal. It is shown that light scattering detection should be used with careful control of fractionating power to obtain optimized analysis of polydisperse samples. Part I is concerned with isocratic operation of As-FlFFF, and part II with programmed operation.

  20. PIV quantification of the flow induced by an ultrasonic horn and numerical modeling of the flow and related processing times.

    Science.gov (United States)

    Schenker, M C; Pourquié, M J B M; Eskin, D G; Boersma, B J

    2013-01-01

    The flow in a confined container induced by an ultrasonic horn is measured by Particle Image Velocimetry (PIV). This flow is caused by acoustic streaming and highly influenced by the presence of cavitation. The jet-like experimentally observed flow is compared with the available theoretical solution for a turbulent free round jet. The similarity between both flows enables a simplified numerical model to be made, whilst the phenomenon is very difficult to simulate otherwise. The numerical model requires only two parameters, i.e. the flow momentum and turbulent kinetic energy at the position of the horn tip. The simulated flow is used as a basis for the calculation of the time required for the entire liquid volume to pass through the active cavitation region. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Simulated responses of streams and ponds to groundwater withdrawals and wastewater return flows in southeastern Massachusetts

    Science.gov (United States)

    Carlson, Carl S.; Walter, Donald A.; Barbaro, Jeffrey R.

    2015-12-21

    Water use, such as withdrawals, wastewater return flows, and interbasin transfers, can alter streamflow regimes, water quality, and the integrity of aquatic habitat and affect the availability of water for human and ecosystem needs. To provide the information needed to determine alteration of streamflows and pond water levels in southeastern Massachusetts, existing groundwater models of the Plymouth-Carver region and western (Sagamore flow lens) and eastern (Monomoy flow lens) Cape Cod were used to delineate subbasins and simulate long-term average and average monthly streamflows and pond levels for a series of water-use conditions. Model simulations were used to determine the extent to which streamflows and pond levels were altered by comparing simulated streamflows and pond levels under predevelopment conditions with streamflows and pond levels under pumping only and pumping with wastewater return flow conditions. The pumping and wastewater return flow rates used in this study are the same as those used in previously published U.S. Geological Survey studies in southeastern Massachusetts and represent the period from 2000 to 2005. Streamflow alteration for the nontidal portions of streams in southeastern Massachusetts was evaluated within and at the downstream outlets of 78 groundwater subbasins delineated for this study. Evaluation of streamflow alteration at subbasin outlets is consistent with the approach used by the U.S. Geological Survey for the topographically derived subbasins in the rest of Massachusetts.

  2. Robust Detection and Visualization of Jet-Stream Core Lines in Atmospheric Flow.

    Science.gov (United States)

    Kern, Michael; Hewson, Tim; Sadlo, Filip; Westermann, Rudiger; Rautenhaus, Marc

    2018-01-01

    Jet-streams, their core lines and their role in atmospheric dynamics have been subject to considerable meteorological research since the first half of the twentieth century. Yet, until today no consistent automated feature detection approach has been proposed to identify jet-stream core lines from 3D wind fields. Such 3D core lines can facilitate meteorological analyses previously not possible. Although jet-stream cores can be manually analyzed by meteorologists in 2D as height ridges in the wind speed field, to the best of our knowledge no automated ridge detection approach has been applied to jet-stream core detection. In this work, we -a team of visualization scientists and meteorologists-propose a method that exploits directional information in the wind field to extract core lines in a robust and numerically less involved manner than traditional 3D ridge detection. For the first time, we apply the extracted 3D core lines to meteorological analysis, considering real-world case studies and demonstrating our method's benefits for weather forecasting and meteorological research.

  3. Effects of stream discharge, alluvial depth and bar amplitude on hyporheic flow in pool-riffle channels

    Science.gov (United States)

    Daniele Tonina; John M. Buffington

    2011-01-01

    Hyporheic flow results from the interaction between streamflow and channel morphology and is an important component of stream ecosystems because it enhances water and solute exchange between the river and its bed. Hyporheic flow in pool-riffle channels is particularly complex because of three-dimensional topography that spans a range of partially to fully submerged...

  4. Changes in land cover, rainfall and stream flow in Upper Gilgel Abbay catchment, Blue Nile basin – Ethiopia

    Directory of Open Access Journals (Sweden)

    T. H. M. Rientjes

    2011-06-01

    Full Text Available In this study we evaluated changes in land cover and rainfall in the Upper Gilgel Abbay catchment in the Upper Blue Nile basin and how changes affected stream flow in terms of annual flow, high flows and low flows. Land cover change assessment was through classification analysis of remote sensing based land cover data while assessments on rainfall and stream flow data are by statistical analysis. Results of the supervised land cover classification analysis indicated that 50.9 % and 16.7 % of the catchment area was covered by forest in 1973 and 2001, respectively. This significant decrease in forest cover is mainly due to expansion of agricultural land.

    By use of a change detection procedure, three periods were identified for which changes in rainfall and stream flow were analyzed. Rainfall was analyzed at monthly base by use of the Mann-Kendall test statistic and results indicated a statistically significant, decreasing trend for most months of the year. However, for the wet season months of June, July and August rainfall has increased. In the period 1973–2005, the annual flow of the catchment decreased by 12.1 %. Low flow and high flow at daily base were analyzed by a low flow and a high flow index that is based on a 95 % and 5 % exceedance probability. Results of the low flow index indicated decreases of 18.1 % and 66.6 % for the periods 1982–2000 and 2001–2005 respectively. Results of high flows indicated an increase of 7.6 % and 46.6 % for the same periods. In this study it is concluded that over the period 1973–2005 stream flow has changed in the Gilgel Abbay catchment by changes in land cover and changes in rainfall.

  5. River Stream-Flow and Zayanderoud Reservoir Operation Modeling Using the Fuzzy Inference System

    Directory of Open Access Journals (Sweden)

    Saeed Jamali

    2007-12-01

    Full Text Available The Zayanderoud basin is located in the central plateau of Iran. As a result of population increase and agricultural and industrial developments, water demand on this basin has increased extensively. Given the importance of reservoir operation in water resource and management studies, the performance of fuzzy inference system (FIS for Zayanderoud reservoir operation is investigated in this paper. The model of operation consists of two parts. In the first part, the seasonal river stream-flow is forecasted using the fuzzy rule-based system. The southern oscillated index, rain, snow, and discharge are inputs of the model and the seasonal river stream-flow its output. In the second part, the operation model is constructed. The amount of releases is first optimized by a nonlinear optimization model and then the rule curves are extracted using the fuzzy inference system. This model operates on an "if-then" principle, where the "if" is a vector of fuzzy permits and "then" is the fuzzy result. The reservoir storage capacity, inflow, demand, and year condition factor are used as permits. Monthly release is taken as the consequence. The Zayanderoud basin is investigated as a case study. Different performance indices such as reliability, resiliency, and vulnerability are calculated. According to results, FIS works more effectively than the traditional reservoir operation methods such as standard operation policy (SOP or linear regression.

  6. Effect of Free Stream Turbulence on the Flow-Induced Background Noise of In-Flow Microphones

    Science.gov (United States)

    Allen, Christopher S.; Olson, Lawrence E. (Technical Monitor)

    1998-01-01

    When making noise measurements of sound sources in flow using microphones immersed in an air stream or wind tunnel, the factor limiting the dynamic range of the measurement is, in many cases, the noise caused by the flow over the microphone. To lower this self-noise, and to protect the microphone diaphragm, an aerodynamic microphone forebody is usually mounted on the tip of the omnidirectional microphone. The microphone probe is then pointed into the wind stream. Even with a microphone forebody, however, the self-noise persists, prompting further research in the area of microphone forebody design for flow-induced self-noise reduction. The magnitude and frequency characteristics of in-flow microphone probe self-noise is dependent upon the exterior shape of the probe and on the level of turbulence in the onset flow, among other things. Several recent studies present new designs for microphone forebodies, some showing the forbodies' self-noise characteristics when used in a given facility. However, these self-noise characteristics may change when the probes are used in different facilities. The present paper will present results of an experimental investigation to determine an empirical relationship between flow turbulence and self-noise levels for several microphone forebody shapes as a function of frequency. As a result, the microphone probe self-noise for these probes will be known as a function of freestream turbulence, and knowing the freestream turbulence spectra for a given facility, the probe self-noise can be predicted. Flow-induced microphone self-noise is believed to be related to the freestream. turbulence by three separate mechanisms. The first mechanism is produced by large scale, as compared to the probe size, turbulence which appears to the probe as a variation in the angle of attack of the freestream. flow. This apparent angle of attack variation causes the pressure along the probe surface to fluctuate, and at the location of the sensor orifice this

  7. Controlling flow time delays in flexible manufacturing cells

    NARCIS (Netherlands)

    Slomp, J.; Caprihan, R.; Bokhorst, J. A. C.

    2009-01-01

    Flow time delays in Flexible Manufacturing Cells (FMCs) are caused by transport and clamping/reclamping activities. This paper shows how dynamic scheduling parameters may control the flow times of jobs and the available task windows for flow time delays.

  8. Methods for estimating flow-duration curve and low-flow frequency statistics for ungaged locations on small streams in Minnesota

    Science.gov (United States)

    Ziegeweid, Jeffrey R.; Lorenz, David L.; Sanocki, Chris A.; Czuba, Christiana R.

    2015-12-24

    Knowledge of the magnitude and frequency of low flows in streams, which are flows in a stream during prolonged dry weather, is fundamental for water-supply planning and design; waste-load allocation; reservoir storage design; and maintenance of water quality and quantity for irrigation, recreation, and wildlife conservation. This report presents the results of a statewide study for which regional regression equations were developed for estimating 13 flow-duration curve statistics and 10 low-flow frequency statistics at ungaged stream locations in Minnesota. The 13 flow-duration curve statistics estimated by regression equations include the 0.0001, 0.001, 0.02, 0.05, 0.1, 0.25, 0.50, 0.75, 0.9, 0.95, 0.99, 0.999, and 0.9999 exceedance-probability quantiles. The low-flow frequency statistics include annual and seasonal (spring, summer, fall, winter) 7-day mean low flows, seasonal 30-day mean low flows, and summer 122-day mean low flows for a recurrence interval of 10 years. Estimates of the 13 flow-duration curve statistics and the 10 low-flow frequency statistics are provided for 196 U.S. Geological Survey continuous-record streamgages using streamflow data collected through September 30, 2012.

  9. An Application of Value Stream Mapping in Production Flow Analysis: A lean approach in An Automotive Industry

    Directory of Open Access Journals (Sweden)

    Krushnaraj Bodana

    2016-08-01

    Full Text Available Lean manufacturing deals with a manufacturing process improvement based on the fundamental goal of Toyota production system in order to minimize or eliminate waste while maximizing production flow. Today in a highly competitive local and global market, it is very much crucial to satisfy the changing demand of the customers. Thus, in today’s manufacturing industry there is an increased focus to produce the right product at right time. The prime objective of this paper to apply a significant lean manufacturing tool know as Value Stream Mapping (VSM. To fulfil this objective a fundamental principles of lean were implemented and VSM was generated to analyse the production flow at an automotive industry and improve the current operating condition to overcome the difficulties with current state of work through time study, Takt time calculation, modifying work cell layout. And based on the future state of VSM, final results showed that by implementing this lean techniques, Production Lead-time (PLT decreased from 7.6 days to 3.2 days, and the cycle time is decrease up to 73%.

  10. Mining Frequent Item Sets in Asynchronous Transactional Data Streams over Time Sensitive Sliding Windows Model

    International Nuclear Information System (INIS)

    Javaid, Q.; Memon, F.; Talpur, S.; Arif, M.; Awan, M.D.

    2016-01-01

    EPs (Extracting Frequent Patterns) from the continuous transactional data streams is a challenging and critical task in some of the applications, such as web mining, data analysis and retail market, prediction and network monitoring, or analysis of stock market exchange data. Many algorithms have been developed previously for mining FPs (Frequent Patterns) from a data stream. Such algorithms are currently highly required to develop new solutions and approaches to the precise handling of data streams. New techniques, solutions, or approaches are developed to address unbounded, ordered, and continuous sequences of data and for the generation of data at a rapid speed from data streams. Hence, extracting FPs using fresh or recent data involves the high-level analysis of data streams. We have suggested an efficient technique for the window sliding model; this technique extracts new and fresh FPs from high-speed data streams. In this study, a CPILT (Compacted Tree Compact Pattern Tree) is developed to capture the latest contents in the stream and to efficiently remove outdated contents from the data stream. The main concept introduced in this work on CPILT is the dynamic restructuring of a tree, which is helpful in producing a compacted tree and the frequency descending structure of a tree on runtime. With the help of the mining technique of FP growth, a complete list of new and fresh FPs is obtained from a CPILT using an existing window. The memory usage and time complexity of the latest FPs in high-speed data streams can efficiently be determined through proper experimentation and analysis. (author)

  11. Regional regression equations for the estimation of selected monthly low-flow duration and frequency statistics at ungaged sites on streams in New Jersey

    Science.gov (United States)

    Watson, Kara M.; McHugh, Amy R.

    2014-01-01

    representative of the increased development of the last 20 years (1989–2008). The two different land- and water-use conditions were used as surrogates for development to determine whether there have been changes in low-flow statistics as a result of changes in development over time. The State was divided into two low-flow regression regions, the Coastal Plain and the non-coastal region, in order to improve the accuracy of the regression equations. The left-censored parametric survival regression method was used for the analyses to account for streamgages and partial-record stations that had zero flow values for some of the statistics. The average standard error of estimate for the 348 regression equations ranged from 16 to 340 percent. These regression equations and basin characteristics are presented in the U.S. Geological Survey (USGS) StreamStats Web-based geographic information system application. This tool allows users to click on an ungaged site on a stream in New Jersey and get the estimated flow-duration and low-flow frequency statistics. Additionally, the user can click on a streamgage or partial-record station and get the “at-site” streamflow statistics. The low-flow characteristics of a stream ultimately affect the use of the stream by humans. Specific information on the low-flow characteristics of streams is essential to water managers who deal with problems related to municipal and industrial water supply, fish and wildlife conservation, and dilution of wastewater.

  12. Source modulation-correlation measurement for fissile mass flow in gas or liquid fissile streams

    International Nuclear Information System (INIS)

    Mihalczo, J.T.; March-Leuba, J.A.; Valentine, T.E.; Abston, R.A.; Mattingly, J.K.; Mullens, J.A.

    1996-01-01

    The method of monitoring fissile mass flow on all three legs of a blending point, where the input is high-enriched uranium (HEU) and low-enriched uranium (LEU) and the product is PEU, can yield the fissile stream velocity and, with calibration, the [sup235]U content. The product of velocity and content integrated over the pipe gives the fissile mass flow in each leg. Also, the ratio of fissile contents in each pipe: HEU/LEU, HEU/PEU, and PEU/LEU, are obtained. By modulating the source on the input HEU pipe differently from that on the output pipe, the HEU gas can be tracked through the blend point. This method can be useful for monitoring flow velocity, fissile content, and fissile mass flow in HEU blenddown of UF[sub 6] if the pressures are high enough to contain some of the induced fission products. This method can also be used to monitor transfer of fissile liquids and other gases and liquids that emit radiation delayed from particle capture. These preliminary experiments with the Oak Ridge apparatus show that the method will work and the modeling is adequate

  13. Monitoring strategies of stream phosphorus under contrasting climate-driven flow regimes

    DEFF Research Database (Denmark)

    Goyenola, Guillermo; Meerhoff, Marianna; Teixeira-de Mello, Franco

    2015-01-01

    Climate and hydrology are relevant control factors determining the timing and amount of nutrient losses from land to downstream aquatic systems, in particular of phosphorus (P) from agricultural lands. The main objective of the study was to evaluate the differences in P export patterns and the pe......Climate and hydrology are relevant control factors determining the timing and amount of nutrient losses from land to downstream aquatic systems, in particular of phosphorus (P) from agricultural lands. The main objective of the study was to evaluate the differences in P export patterns...... applied two alternative nutrient sampling programs (high-frequency composite sampling and low-frequency instantaneous-grab sampling) and estimated the contribution derived from point and diffuse sources fitting a source apportionment model. We expected to detect a pattern of higher total and particulate...... program to estimate P exports in flashy streams compared to the less variable streams. We also found signs of interaction between climate/hydrology and land use intensity, in particular in the presence of point sources of P, leading to a bias towards underestimation of P in hydrologically stable streams...

  14. Flow under standing waves Part 1. Shear stress distribution, energy flux and steady streaming

    DEFF Research Database (Denmark)

    Gislason, Kjartan; Fredsøe, Jørgen; Deigaard, Rolf

    2009-01-01

    The conditions for energy flux, momentum flux and the resulting streaming velocity are analysed for standing waves formed in front of a fully reflecting wall. The exchange of energy between the outer wave motion and the near bed oscillatory boundary layer is considered, determining the horizontal...... energy flux inside and outside the boundary layer. The momentum balance, the mean shear stress and the resulting time averaged streaming velocities are determined. For a laminar bed boundary layer the analysis of the wave drift gives results similar to the original work of Longuet-Higgins from 1953......-dimensional simulations of standing waves have also been made by application of a general purpose Navier-Stokes solver. The results agree well with those obtained by the boundary layer analysis. Wave reflection from a plane sloping wall is also investigated by using the same numerical model and by physical laboratory...

  15. A Fast Density-Based Clustering Algorithm for Real-Time Internet of Things Stream

    Science.gov (United States)

    Ying Wah, Teh

    2014-01-01

    Data streams are continuously generated over time from Internet of Things (IoT) devices. The faster all of this data is analyzed, its hidden trends and patterns discovered, and new strategies created, the faster action can be taken, creating greater value for organizations. Density-based method is a prominent class in clustering data streams. It has the ability to detect arbitrary shape clusters, to handle outlier, and it does not need the number of clusters in advance. Therefore, density-based clustering algorithm is a proper choice for clustering IoT streams. Recently, several density-based algorithms have been proposed for clustering data streams. However, density-based clustering in limited time is still a challenging issue. In this paper, we propose a density-based clustering algorithm for IoT streams. The method has fast processing time to be applicable in real-time application of IoT devices. Experimental results show that the proposed approach obtains high quality results with low computation time on real and synthetic datasets. PMID:25110753

  16. A fast density-based clustering algorithm for real-time Internet of Things stream.

    Science.gov (United States)

    Amini, Amineh; Saboohi, Hadi; Wah, Teh Ying; Herawan, Tutut

    2014-01-01

    Data streams are continuously generated over time from Internet of Things (IoT) devices. The faster all of this data is analyzed, its hidden trends and patterns discovered, and new strategies created, the faster action can be taken, creating greater value for organizations. Density-based method is a prominent class in clustering data streams. It has the ability to detect arbitrary shape clusters, to handle outlier, and it does not need the number of clusters in advance. Therefore, density-based clustering algorithm is a proper choice for clustering IoT streams. Recently, several density-based algorithms have been proposed for clustering data streams. However, density-based clustering in limited time is still a challenging issue. In this paper, we propose a density-based clustering algorithm for IoT streams. The method has fast processing time to be applicable in real-time application of IoT devices. Experimental results show that the proposed approach obtains high quality results with low computation time on real and synthetic datasets.

  17. Real-time analytics techniques to analyze and visualize streaming data

    CERN Document Server

    Ellis, Byron

    2014-01-01

    Construct a robust end-to-end solution for analyzing and visualizing streaming data Real-time analytics is the hottest topic in data analytics today. In Real-Time Analytics: Techniques to Analyze and Visualize Streaming Data, expert Byron Ellis teaches data analysts technologies to build an effective real-time analytics platform. This platform can then be used to make sense of the constantly changing data that is beginning to outpace traditional batch-based analysis platforms. The author is among a very few leading experts in the field. He has a prestigious background in research, development,

  18. Cache Timing Analysis of LFSR-based Stream Ciphers

    DEFF Research Database (Denmark)

    Zenner, Erik; Leander, Gregor; Hawkes, Philip

    2009-01-01

    Cache timing attacks are a class of side-channel attacks that is applicable against certain software implementations. They have generated significant interest when demonstrated against the Advanced Encryption Standard (AES), but have more recently also been applied against other cryptographic...

  19. Instream flow assessment of streams draining the Arbuckle-Simpson Aquifer

    Science.gov (United States)

    Seilheimer, Titus S.; Fisher, William L.

    2008-01-01

    The availability of high quality water is critical to both humans and ecosystems. A recent proposal was made by rapidly expanding municipalities in central Oklahoma to begin transferring groundwater from the Arbuckle-Simpson aquifer, a sensitive sole-source aquifer in south-central Oklahoma. Concerned citizens and municipalities living on and getting their drinking water from the Arbuckle-Simpson lobbied the legislature to pass a temporary moratorium on groundwater transfer to allow for a comprehensive study of the aquifer and its ecosystems. We conducted an instream flow assessment using Physical Habitat Simulation (PHABSIM) on springs and streams with four spring-dependent species: two minnows, southern redbelly dace (Phoxinus erthyrogaster) and redspot chub (Nocomis asper); and two darters, least darter (Etheostoma microperca) and orangethroat darter (Etheostoma spectabile). Spring habitats are unique compared to other river habitats because they have constant flow and temperature, small and isolated habitat patches, and a general lack of predators. Our study sites included two spring-fed streams, one larger stream with high groundwater inputs, and a river with both groundwater and surface water inputs that is adjacent to the small spring-fed streams. These habitats meet the criteria for groundwater dependent ecosystems because they would not exist without the surface expression of groundwater. A total of 99 transects in all four sites were surveyed for channel elevation, and three sets of water surface elevation and water velocity were measured. Habitat suitability criteria were derived for the species at each site using nonparametric confidence limits based on underwater observations made by snorkelers. Simulations of flow were focused on declines in discharge, which is the expected effect of the proposed groundwater diversion. Our results show that only a small proportion of the total available area in each habitat is considered to be preferred habitat

  20. Effects of soil data resolution on SWAT model stream flow and water quality predictions.

    Science.gov (United States)

    Geza, Mengistu; McCray, John E

    2008-08-01

    The prediction accuracy of agricultural nonpoint source pollution models such as Soil and Water Assessment Tool (SWAT) depends on how well model input spatial parameters describe the characteristics of the watershed. The objective of this study was to assess the effects of different soil data resolutions on stream flow, sediment and nutrient predictions when used as input for SWAT. SWAT model predictions were compared for the two US Department of Agriculture soil databases with different resolution, namely the State Soil Geographic database (STATSGO) and the Soil Survey Geographic database (SSURGO). Same number of sub-basins was used in the watershed delineation. However, the number of HRUs generated when STATSGO and SSURGO soil data were used is 261 and 1301, respectively. SSURGO, with the highest spatial resolution, has 51 unique soil types in the watershed distributed in 1301 HRUs, while STATSGO has only three distributed in 261 HRUS. As a result of low resolution STATSGO assigns a single classification to areas that may have different soil types if SSURGO were used. SSURGO included Hydrologic Response Units (HRUs) with soil types that were generalized to one soil group in STATSGO. The difference in the number and size of HRUs also has an effect on sediment yield parameters (slope and slope length). Thus, as a result of the discrepancies in soil type and size of HRUs stream flow predicted was higher when SSURGO was used compared to STATSGO. SSURGO predicted less stream loading than STATSGO in terms of sediment and sediment-attached nutrients components, and vice versa for dissolved nutrients. When compared to mean daily measured flow, STATSGO performed better relative to SSURGO before calibration. SSURGO provided better results after calibration as evaluated by R(2) value (0.74 compared to 0.61 for STATSGO) and the Nash-Sutcliffe coefficient of Efficiency (NSE) values (0.70 and 0.61 for SSURGO and STATSGO, respectively) although both are in the same satisfactory

  1. NUMERICAL ANALYSIS OF INFLUENCE OF EXOGENOUS FIRE IN DOG HEADING ON PARAMETERS OF THE AIR STREAM FLOWING THROUGH THIS HEADING

    Directory of Open Access Journals (Sweden)

    Magdalena TUTAK

    2014-04-01

    Full Text Available Flow of ventilation air stream through the dog heading with a fire centre is the flow with complex character, during which as a result of emission of fire gases into the mining atmosphere, there occur to disturbances of its flow. In the paper there is presented a numerical analysis of an influence of exogenous fire in a dog heading, on the parameters of the ventilation air stream flowing through this heading. Modeling tests were carried out with a use of ANSYS software, basing on the Finite Volume Method. For the made assumptions, there were determined physical parameters of air stream flowing through the heading with a fire centre, and also changes in mass fraction of gases in this stream during its flow through the analyzed heading: oxygen, carbon monoxide and carbon dioxide. As a result of performed analysis over the fire centre, the local increase of velocity and temperature and violent decrease of static pressure were recorded. Model of heading presented in the paper gives possibilities for development, and then the analysis of more complicated problems in a range of ventilation of mining headings.

  2. The effect of bedload transport rates on bedform and planform morphological development in a laboratory meandering stream under varying flow conditions

    Science.gov (United States)

    Sullivan, C.; Good, R. G. R.; Binns, A. D.

    2017-12-01

    Sediment transport processes in streams provides valuable insight into the temporal evolution of planform and bedform geometry. The majority of previous experimental research in the literature has focused on bedload transport and corresponding bedform development in rectangular, confined channels, which does not consider planform adjustment processes in streams. In contrast, research conducted with laboratory streams having movable banks can investigate planform development in addition to bedform development, which is more representative of natural streams. The goal of this research is to explore the relationship between bedload transport rates and the morphological adjustments in meandering streams. To accomplish this, a series of experimental runs were conducted in a 5.6 m by 1.9 m river basin flume at the University of Guelph to analyze the bedload impacts on bed formations and planform adjustments in response to varying flow conditions. In total, three experimental runs were conducted: two runs using steady state conditions and one run using unsteady flow conditions in the form of a symmetrical hydrograph implementing quasi steady state flow. The runs were performed in a series of time-steps in order to monitor the evolution of the stream morphology and the bedload transport rates. Structure from motion (SfM) was utilized to capture the channel morphology after each time-step, and Agisoft PhotoScan software was used to produce digital elevation models to analyze the morphological evolution of the channel with time. Bedload transport rates were quantified using a sediment catch at the end of the flume. Although total flow volumes were similar for each run, the morphological evolution and bedload transport rates in each run varied. The observed bedload transport rates from the flume are compared with existing bedload transport formulas to assess their accuracy with respect to sediment transport in unconfined meandering channels. The measured sediment transport

  3. Real-time skin feature identification in a time-sequential video stream

    Science.gov (United States)

    Kramberger, Iztok

    2005-04-01

    Skin color can be an important feature when tracking skin-colored objects. Particularly this is the case for computer-vision-based human-computer interfaces (HCI). Humans have a highly developed feeling of space and, therefore, it is reasonable to support this within intelligent HCI, where the importance of augmented reality can be foreseen. Joining human-like interaction techniques within multimodal HCI could, or will, gain a feature for modern mobile telecommunication devices. On the other hand, real-time processing plays an important role in achieving more natural and physically intuitive ways of human-machine interaction. The main scope of this work is the development of a stereoscopic computer-vision hardware-accelerated framework for real-time skin feature identification in the sense of a single-pass image segmentation process. The hardware-accelerated preprocessing stage is presented with the purpose of color and spatial filtering, where the skin color model within the hue-saturation-value (HSV) color space is given with a polyhedron of threshold values representing the basis of the filter model. An adaptive filter management unit is suggested to achieve better segmentation results. This enables the adoption of filter parameters to the current scene conditions in an adaptive way. Implementation of the suggested hardware structure is given at the level of filed programmable system level integrated circuit (FPSLIC) devices using an embedded microcontroller as their main feature. A stereoscopic clue is achieved using a time-sequential video stream, but this shows no difference for real-time processing requirements in terms of hardware complexity. The experimental results for the hardware-accelerated preprocessing stage are given by efficiency estimation of the presented hardware structure using a simple motion-detection algorithm based on a binary function.

  4. Implicit time accurate simulation of unsteady flow

    Science.gov (United States)

    van Buuren, René; Kuerten, Hans; Geurts, Bernard J.

    2001-03-01

    Implicit time integration was studied in the context of unsteady shock-boundary layer interaction flow. With an explicit second-order Runge-Kutta scheme, a reference solution to compare with the implicit second-order Crank-Nicolson scheme was determined. The time step in the explicit scheme is restricted by both temporal accuracy as well as stability requirements, whereas in the A-stable implicit scheme, the time step has to obey temporal resolution requirements and numerical convergence conditions. The non-linear discrete equations for each time step are solved iteratively by adding a pseudo-time derivative. The quasi-Newton approach is adopted and the linear systems that arise are approximately solved with a symmetric block Gauss-Seidel solver. As a guiding principle for properly setting numerical time integration parameters that yield an efficient time accurate capturing of the solution, the global error caused by the temporal integration is compared with the error resulting from the spatial discretization. Focus is on the sensitivity of properties of the solution in relation to the time step. Numerical simulations show that the time step needed for acceptable accuracy can be considerably larger than the explicit stability time step; typical ratios range from 20 to 80. At large time steps, convergence problems that are closely related to a highly complex structure of the basins of attraction of the iterative method may occur. Copyright

  5. Real-time video streaming in mobile cloud over heterogeneous wireless networks

    Science.gov (United States)

    Abdallah-Saleh, Saleh; Wang, Qi; Grecos, Christos

    2012-06-01

    Recently, the concept of Mobile Cloud Computing (MCC) has been proposed to offload the resource requirements in computational capabilities, storage and security from mobile devices into the cloud. Internet video applications such as real-time streaming are expected to be ubiquitously deployed and supported over the cloud for mobile users, who typically encounter a range of wireless networks of diverse radio access technologies during their roaming. However, real-time video streaming for mobile cloud users across heterogeneous wireless networks presents multiple challenges. The network-layer quality of service (QoS) provision to support high-quality mobile video delivery in this demanding scenario remains an open research question, and this in turn affects the application-level visual quality and impedes mobile users' perceived quality of experience (QoE). In this paper, we devise a framework to support real-time video streaming in this new mobile video networking paradigm and evaluate the performance of the proposed framework empirically through a lab-based yet realistic testing platform. One particular issue we focus on is the effect of users' mobility on the QoS of video streaming over the cloud. We design and implement a hybrid platform comprising of a test-bed and an emulator, on which our concept of mobile cloud computing, video streaming and heterogeneous wireless networks are implemented and integrated to allow the testing of our framework. As representative heterogeneous wireless networks, the popular WLAN (Wi-Fi) and MAN (WiMAX) networks are incorporated in order to evaluate effects of handovers between these different radio access technologies. The H.264/AVC (Advanced Video Coding) standard is employed for real-time video streaming from a server to mobile users (client nodes) in the networks. Mobility support is introduced to enable continuous streaming experience for a mobile user across the heterogeneous wireless network. Real-time video stream packets

  6. The influence of stream bed geomorphology on chemical species within the hyporheic zone over time and space

    Science.gov (United States)

    Quick, A. M.; Reeder, W. J.; Farrell, T. B.; Benner, S. G.; Tonina, D.; Feris, K. P.

    2017-12-01

    The hyporheic zone is well established as an important zone of biogeochemical activity in streams and rivers. Multiple large scale flume experiments were carried out to mimic bedform-controlled hyporheic zones in small streams. The laboratory setting allowed for geochemical measurement resolution and replicates that would not be possible in a natural setting. Two flume experiments that consisted of three small streams with variable sizes of bedform dunes were carried out in which chemical species were measured in the surface water and along hyporheic flow lines in the subsurface. The species measured included dissolved oxygen, pH, alkalinity, major cations (Na+, Mg2+, Ca2+, K+, Si4+, Al3+), anions (NO3-, NO2-, SO42-, PO43-, Cl-), and many trace elements (As, Sr, Co, Ni, Cu, Zn, Pb, U, V). Observed spatial and temporal trends reflect microbiological processes, changing redox conditions, and chemical weathering. In general, microbial respiration causes DO to decrease with residence time, leading to aerobic and anaerobic zones that influence redox-sensitive species and pH gradients that influence mineral solubility. Most other species concentrations, including those of major cations and trace elements, increase with residence time and generally decrease over time elapsed during the experiment. The different dune morphologies dictate flow velocities in the hyporheic zone; for most species, steeper dunes with higher velocities had lower concentrations at the end of the experiment, indicating the role of dune shape in the weathering rates of minerals in hyporheic sediment and the concentrations of dissolved species entering the surface water over time. Many of the observed trends can be applied, at least qualitatively, to understanding how these species will behave in natural settings. This insight will contribute to the understanding of many of the applications of the hyporheic zone (e.g. bioremediation, habitat, greenhouse gas emissions, etc.).

  7. Low-flow frequency and flow-duration characteristics of selected streams in Alabama through March 2014

    Science.gov (United States)

    Feaster, Toby D.; Lee, Kathyrn G.

    2017-08-28

    Low-flow statistics are needed by water-resource engineers, planners, and managers to protect and manage the water resources of Alabama. The accuracy of these statistics is influenced by such factors as length of record and specific hydrologic conditions measured in those records. As such, it is generally recommended that flow statistics be updated about every 10 years to provide improved and representative low-flow characteristics. The previous investigation of low-flow characteristics for Alabama included data through September 1990. Since that time, Alabama has experienced several historic droughts highlighting the need to update the low-flow characteristics at U.S. Geological Survey streamgaging stations. Consequently, this investigation was undertaken in cooperation with a number of State and local agencies to update low-flow frequency and flow-duration statistics at 210 continuous-record streamgaging stations in Alabama and 67 stations from basins that are shared with surrounding States. The flow characteristics were computed on the basis of available data through March 2014.

  8. Analysis and optimization techniques for real-time streaming image processing software on general purpose systems

    NARCIS (Netherlands)

    Westmijze, Mark

    2018-01-01

    Commercial Off The Shelf (COTS) Chip Multi-Processor (CMP) systems are for cost reasons often used in industry for soft real-time stream processing. COTS CMP systems typically have a low timing predictability, which makes it difficult to develop software applications for these systems with tight

  9. Automatic dataflow model extraction from modal real-time stream processing applications

    NARCIS (Netherlands)

    Geuns, S.J.; Hausmans, J.P.H.M.; Bekooij, Marco Jan Gerrit

    2013-01-01

    Many real-time stream processing applications are initially described as a sequential application containing while-loops, which execute for an unknown number of iterations. These modal applications have to be executed in parallel on an MPSoC system in order to meet their real-time throughput

  10. Defining and measuring the mean residence time of lateral surface transient storage zones in small streams

    Science.gov (United States)

    T.R. Jackson; R. Haggerty; S.V. Apte; A. Coleman; K.J. Drost

    2012-01-01

    Surface transient storage (STS) has functional significance in stream ecosystems because it increases solute interaction with sediments. After volume, mean residence time is the most important metric of STS, but it is unclear how this can be measured accurately or related to other timescales and field-measureable parameters. We studied mean residence time of lateral...

  11. Sequential Specification of Time-aware Stream Processing Applications (Extended Abstract)

    NARCIS (Netherlands)

    Geuns, S.J.; Hausmans, J.P.H.M.; Bekooij, Marco Jan Gerrit

    2012-01-01

    Automatic parallelization of Nested Loop Programs (NLPs) is an attractive method to create embedded real-time stream processing applications for multi-core systems. However, the description and parallelization of applications with a time dependent functional behavior has not been considered in NLPs.

  12. Removal of Contaminants from Waste Streams at Gas Evolving Flow-Through Porous Electrodes

    International Nuclear Information System (INIS)

    Mahmoud Saleh, M.

    1999-01-01

    Electrochemical techniques have been used for the removal of inorganic and organic toxic materials from industrial waste streams. One of the most important branch of these electrochemical techniques is the flow-through porous electrode. Such systems allow for the continuous operation and hence continuous removal of the contaminants from waste streams at high rates and high efficiency. However, when there is an evolution of gas bubbles with the removal process, the treatment process needs a much different treatment of both the design and the mathematical treatment of the such these systems. The evolving gas bubbles within the electrode decrease the pore electrolyte conductivity of the porous electrodes, decrease the efficiency and make the current more non-uniform. This cause the under utilization of the reaction area and finally make the electrode inoperable. In this work the harmful effects of the gas bubbles on the performance of the porous electrode will be modeled. The model accounts for the effects of kinetic, mass transfer and gas bubbles resistance on the overall performance of the electrode. This will help in optimizing the operating conditions and the cell design

  13. A numerical study of a turbulent axisymmetric jet emerging in a co-flowing stream

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, Houda, E-mail: mahhouda2003@yahoo.f [Unite de thermique et thermodynamique des procedes industriels, Ecole Nationale d' Ingenieurs de Monastir, route de Ouardanine, 5020 Monastir (Tunisia); Kriaa, Wassim; Mhiri, Hatem [Unite de thermique et thermodynamique des procedes industriels, Ecole Nationale d' Ingenieurs de Monastir, route de Ouardanine, 5020 Monastir (Tunisia); Palec, Georges Le; Bournot, Philippe [IUSTI, UMR CNRS 6595, 5 Rue Enrico Fermi, Technopole de Chateau-Gombert, 13013 Marseille (France)

    2010-11-15

    In this work, we propose a numerical study of an axisymmetric turbulent jet discharging into co-flowing stream with different velocities ratios ranging between 0 and {infinity}. The standard k-{epsilon} model and the RSM model were applied in this study. The numerical resolution of the governing equations was carried out using two computed codes: the first is a personal code and the second is a commercial CFD code FLUENT 6.2. These two codes are based on a finite volume method. The present predictions are compared with the experimental data. The results show that the two turbulence models are valid to predict the average and turbulent flow sizes. Also, the effect of the velocities ratios on the flow structure was examined. For R{sub u} > 1, it is noted the appearance of the fall velocity zone due to the presence of a trough low pressure. This fall velocity becomes increasingly intense according to R{sub u} and changes into a recirculation zone for R{sub u} {>=} 4.5. This zone is larger and approaches more the nozzle injection when R{sub u} increases.

  14. The Effect of Model Grid Resolution on the Distributed Hydrologic Simulations for Forecasting Stream Flows and Reservoir Storage

    Science.gov (United States)

    Turnbull, S. J.

    2017-12-01

    Within the US Army Corps of Engineers (USACE), reservoirs are typically operated according to a rule curve that specifies target water levels based on the time of year. The rule curve is intended to maximize flood protection by specifying releases of water before the dominant rainfall period for a region. While some operating allowances are permissible, generally the rule curve elevations must be maintained. While this operational approach provides for the required flood control purpose, it may not result in optimal reservoir operations for multi-use impoundments. In the Russian River Valley of California a multi-agency research effort called Forecast-Informed Reservoir Operations (FIRO) is assessing the application of forecast weather and streamflow predictions to potentially enhance the operation of reservoirs in the watershed. The focus of the study has been on Lake Mendocino, a USACE project important for flood control, water supply, power generation and ecological flows. As part of this effort the Engineer Research and Development Center is assessing the ability of utilizing the physics based, distributed watershed model Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model to simulate stream flows, reservoir stages, and discharges while being driven by weather forecast products. A key question in this application is the effect of watershed model resolution on forecasted stream flows. To help resolve this question, GSSHA models of multiple grid resolutions, 30, 50, and 270m, were developed for the upper Russian River, which includes Lake Mendocino. The models were derived from common inputs: DEM, soils, land use, stream network, reservoir characteristics, and specified inflows and discharges. All the models were calibrated in both event and continuous simulation mode using measured precipitation gages and then driven with the West-WRF atmospheric model in prediction mode to assess the ability of the model to function in short term, less than one week

  15. Impact of climate change and anthropogenic activities on stream flow and sediment discharge in the Wei River basin, China

    Directory of Open Access Journals (Sweden)

    P. Gao

    2013-03-01

    Full Text Available Reduced stream flow and increased sediment discharge are a major concern in the Yellow River basin of China, which supplies water for agriculture, industry and the growing populations located along the river. Similar concerns exist in the Wei River basin, which is the largest tributary of the Yellow River basin and comprises the highly eroded Loess Plateau. Better understanding of the drivers of stream flow and sediment discharge dynamics in the Wei River basin is needed for development of effective management strategies for the region and entire Yellow River basin. In this regard we analysed long-term trends for water and sediment discharge during the flood season in the Wei River basin, China. Stream flow and sediment discharge data for 1932 to 2008 from existing hydrological stations located in two subcatchments and at two points in the Wei River were analysed. Precipitation and air temperature data were analysed from corresponding meteorological stations. We identified change-points or transition years for the trends by the Pettitt method and, using double mass curves, we diagnosed whether they were caused by precipitation changes, human intervention, or both. We found significant decreasing trends for stream flow and sediment discharge during the flood season in both subcatchments and in the Wei River itself. Change-point analyses further revealed that transition years existed and that rapid decline in stream flow began in 1968 (P P P P P < 0.05, respectively. The impact of precipitation or human activity on the reduction amount after the transition years was estimated by double mass curves of precipitation vs. stream flow (sediment. For reductions in stream flow and sediment discharge, the contribution rate of human activity was found to be 82.80 and 95.56%, respectively, and was significantly stronger than the contribution rate of precipitation. This evidence clearly suggests that, in the absence of significant decreases in precipitation

  16. Real Time Adaptive Stream-oriented Geo-data Filtering

    Directory of Open Access Journals (Sweden)

    A. A. Golovkov

    2016-01-01

    Full Text Available The cutting-edge engineering maintenance software systems of various objects are aimed at processing of geo-location data coming from the employees’ mobile devices in real time. To reduce the amount of transmitted data such systems, usually, use various filtration methods of geo-coordinates recorded directly on mobile devices.The paper identifies the reasons for errors of geo-data coming from different sources, and proposes an adaptive dynamic method to filter geo-location data. Compared with the static method previously described in the literature [1] the approach offers to align adaptively the filtering threshold with changing characteristics of coordinates from many sources of geo-location data.To evaluate the efficiency of the developed filter method have been involved about 400 thousand points, representing motion paths of different type (on foot, by car and high-speed train and parking (indoors, outdoors, near high-rise buildings to take data from different mobile devices. Analysis of results has shown that the benefits of the proposed method are the more precise location of long parking (up to 6 hours and coordinates when user is in motion, the capability to provide steam-oriented filtering of data from different sources that allows to use the approach in geo-information systems, providing continuous monitoring of the location in streamoriented data processing in real time. The disadvantage is a little bit more computational complexity and increasing amount of points of the final track as compared to other filtration techniques.In general, the developed approach enables a significant quality improvement of displayed paths of moving mobile objects.

  17. Post-Processing of Stream Flows in Switzerland with an Emphasis on Low Flows and Floods.

    OpenAIRE

    Bogner Konrad; Liechti Katharina; Zappa Massimiliano

    2016-01-01

    Post processing has received much attention during the last couple of years within the hydrological community and many different methods have been developed and tested especially in the field of flood forecasting. Apart from the different meanings of the phrase “post processing” in meteorology and hydrology in this paper it is regarded as a method to correct model outputs (predictions) based on meteorological (1) observed input data (2) deterministic forecasts (single time series) and (3) ens...

  18. The multi-stream flows and the dynamics of the cosmic web

    International Nuclear Information System (INIS)

    Shandarin, Sergei F.

    2011-01-01

    A new numerical technique to identify the cosmic web is proposed. It is based on locating multi-stream flows, i.e. the places where the velocity field is multi-valued. The method is local in Eulerian space, simple and computationally efficient. This technique uses the velocities of particles and thus takes into account the dynamical information. This is in contrast with the majority of standard methods that use the coordinates of particles only. Two quantities are computed in every mesh cell: the mean and variance of the velocity field. Ideally in the cells where the velocity is single-valued the variance must be equal to zero exactly, therefore the cells with non-zero variance are identified as multi-stream flows. The technique has been tested in the Zel'dovich approximation and in the N-body simulation of the ΛCDM model. The effect of numerical noise is discussed. The web identified by the new method has been compared with the web identified by the standard technique using only the particle coordinates. The comparison has shown overall similarity of two webs as expected, however they by no means are identical. For example, the isocontours of the corresponding fields have significantly different shapes and some density peaks of similar heights exhibit significant differences in the velocity variance and vice versa. This suggests that the density and velocity variance have a significant degree of independence. The shape of the two-dimensional pdf of density and velocity variance confirms this proposition. Thus, we conclude that the dynamical information probed by this technique introduces an additional dimension into analysis of the web

  19. The multi-stream flows and the dynamics of the cosmic web

    Energy Technology Data Exchange (ETDEWEB)

    Shandarin, Sergei F., E-mail: sergei@ku.edu [Department of Physics and Astronomy, University of Kansas, 10082 Malott Hall, 1251 Wescoe Hall Dr, Lawrence, Kansas, 66045 (United States)

    2011-05-01

    A new numerical technique to identify the cosmic web is proposed. It is based on locating multi-stream flows, i.e. the places where the velocity field is multi-valued. The method is local in Eulerian space, simple and computationally efficient. This technique uses the velocities of particles and thus takes into account the dynamical information. This is in contrast with the majority of standard methods that use the coordinates of particles only. Two quantities are computed in every mesh cell: the mean and variance of the velocity field. Ideally in the cells where the velocity is single-valued the variance must be equal to zero exactly, therefore the cells with non-zero variance are identified as multi-stream flows. The technique has been tested in the Zel'dovich approximation and in the N-body simulation of the ΛCDM model. The effect of numerical noise is discussed. The web identified by the new method has been compared with the web identified by the standard technique using only the particle coordinates. The comparison has shown overall similarity of two webs as expected, however they by no means are identical. For example, the isocontours of the corresponding fields have significantly different shapes and some density peaks of similar heights exhibit significant differences in the velocity variance and vice versa. This suggests that the density and velocity variance have a significant degree of independence. The shape of the two-dimensional pdf of density and velocity variance confirms this proposition. Thus, we conclude that the dynamical information probed by this technique introduces an additional dimension into analysis of the web.

  20. Beyond Rating Curves: Time Series Models for in-Stream Turbidity Prediction

    Science.gov (United States)

    Wang, L.; Mukundan, R.; Zion, M.; Pierson, D. C.

    2012-12-01

    The New York City Department of Environmental Protection (DEP) manages New York City's water supply, which is comprised of over 20 reservoirs and supplies over 1 billion gallons of water per day to more than 9 million customers. DEP's "West of Hudson" reservoirs located in the Catskill Mountains are unfiltered per a renewable filtration avoidance determination granted by the EPA. While water quality is usually pristine, high volume storm events occasionally cause the reservoirs to become highly turbid. A logical strategy for turbidity control is to temporarily remove the turbid reservoirs from service. While effective in limiting delivery of turbid water and reducing the need for in-reservoir alum flocculation, this strategy runs the risk of negatively impacting water supply reliability. Thus, it is advantageous for DEP to understand how long a particular turbidity event will affect their system. In order to understand the duration, intensity and total load of a turbidity event, predictions of future in-stream turbidity values are important. Traditionally, turbidity predictions have been carried out by applying streamflow observations/forecasts to a flow-turbidity rating curve. However, predictions from rating curves are often inaccurate due to inter- and intra-event variability in flow-turbidity relationships. Predictions can be improved by applying an autoregressive moving average (ARMA) time series model in combination with a traditional rating curve. Since 2003, DEP and the Upstate Freshwater Institute have compiled a relatively consistent set of 15-minute turbidity observations at various locations on Esopus Creek above Ashokan Reservoir. Using daily averages of this data and streamflow observations at nearby USGS gauges, flow-turbidity rating curves were developed via linear regression. Time series analysis revealed that the linear regression residuals may be represented using an ARMA(1,2) process. Based on this information, flow-turbidity regressions with

  1. Instream flow characterization of upper Salmon River Basin streams, Central Idaho, 2003

    Science.gov (United States)

    Maret, Terry R.; Hortness, Jon E.; Ott, Douglas S.

    2004-01-01

    Anadromous fish populations in the Columbia River Basin have plummeted in the last 100 years. This severe decline led to Federal listing of chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) stocks as endangered or threatened under the Endangered Species Act (ESA) in the 1990s. Historically, the upper Salmon River Basin (upstream from the confluence with the Pahsimeroi River) in Idaho provided migration corridors and significant habitat for these ESA-listed species, in addition to the federally listed bull trout (Salvelinus confluentus). Human development has modified the original streamflow conditions in many streams in the upper Salmon River Basin. Summer streamflow modifications, as a result of irrigation practices, have directly affected the quantity and quality of fish habitat and also have affected migration and (or) access to suitable spawning and rearing habitat for these fish. As a result of these ESA listings and Action 149 of the Federal Columbia River Power System Biological Opinion of 2000, the Bureau of Reclamation was tasked to conduct streamflow characterization studies in the upper Salmon River Basin to clearly define habitat requirements for effective species management and habitat restoration. These studies include the collection of habitat and streamflow information for the Physical Habitat Simulation (PHABSIM) model, a widely applied method to determine relations between habitat and discharge requirements for various fish species and life stages. Model results can be used by resource managers to guide habitat restoration efforts in the evaluation of potential fish habitat and passage improvements by increasing streamflow. Instream flow characterization studies were completed on Pole, Fourth of July, Elk, and Valley Creeks during 2003. Continuous streamflow data were collected upstream from all diversions on each stream. In addition, natural summer streamflows were estimated for each study site using regression

  2. Time evolution of tokamak states with flow

    International Nuclear Information System (INIS)

    Kerner, W.; Weitzner, H.

    1985-12-01

    The general dissipative Braginskii single-fluid model is applied to simulate tokamak transport. An expansion with respect to epsilon = (ω/sub i/tau/sub i/) -1 , the factor by which perpendicular and parallel transport coefficients differ, yields a numerically tractable scheme. The resulting 1-1/2 D procedure requires computation of 2D toroidal equilibria with flow together with the solution of a system of ordinary 1D flux-averaged equations for the time evolution of the profiles. 13 refs

  3. Idealized flow patterns and transit times in gas/liquid contacting trays with multiple box downcomers

    International Nuclear Information System (INIS)

    D'Arcy, D.

    1977-08-01

    Trays with multiple box downcomers are often used in chemical process plants nowadays. In order to make a theoretical assessment of the mass transfer efficiency of such trays, knowledge is needed of the time spent by the liquid at various parts of the tray. An idealized but reasonable flow pattern has been assumed and the local velocities and transit times along ten equally-spaced stream lines have been computed. Numerical and graphical results are presented. (author)

  4. Streaming flows produced by oscillating interface of magnetic fluid adsorbed on a permanent magnet in alternating magnetic field

    Science.gov (United States)

    Sudo, S.; Ito, M.; Ishimoto, Y.; Nix, S.

    2017-04-01

    This paper describes microstreaming flows generated by oscillating interface of magnetic fluid adsorbed on a circular cylindrical permanent magnet in alternating magnetic field. The interface of magnetic fluid adsorbed on the NdFeB magnet responds to the external alternating magnetic flied as harmonic oscillation. The directions of alternating magnetic field are parallel and antiparallel to the magnetic field of permanent magnet. The oscillation of magnetic fluid interface generates streaming flow around the magnet-magnetic fluid element in water. Microstreaming flows are observed with a high-speed video camera analysis system. The flow pattern generated by magnetic fluid motion depends on the Keulegan-Carpenter number and the Reynolds number.

  5. Variability, trends, and teleconnections of stream flows with large-scale climate signals in the Omo-Ghibe River Basin, Ethiopia.

    Science.gov (United States)

    Degefu, Mekonnen Adnew; Bewket, Woldeamlak

    2017-04-01

    This study assesses variability, trends, and teleconnections of stream flow with large-scale climate signals (global sea surface temperatures (SSTs)) for the Omo-Ghibe River Basin of Ethiopia. Fourteen hydrological indices of variability and extremes were defined from daily stream flow data series and analyzed for two common periods, which are 1972-2006 for 5 stations and 1982-2006 for 15 stations. The Mann-Kendall's test was used to detect trends at 0.05 significance level, and simple correlation analysis was applied to evaluate associations between the selected stream flow indices and SSTs. We found weak and mixed (upward and downward) trend signals for annual and wet (Kiremt) season flows. Indices generated for high-flow (flood) magnitudes showed the same weak trend signals. However, trend tests for flood frequencies and low-flow magnitudes showed little evidences of increasing change. It was also found that El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) are the major anomalies affecting stream flow variability in the Omo-Ghibe Basin. The strongest associations are observed between ENSO/Niño3.4 and the stream flow in August and September, mean Kiremt flow (July-September), and flood frequency (peak over threshold on average three peaks per year (POT3_Fre)). The findings of this study provide a general overview on the long-term stream flow variability and predictability of stream flows for the Omo-Ghibe River Basin.

  6. Impacts of Rainfall Variability, Land Use and Land Cover Change on Stream Flow of the Black Volta Basin, West Africa

    Directory of Open Access Journals (Sweden)

    Komlavi Akpoti

    2016-07-01

    Full Text Available Potential implications of rainfall variability along with Land Use and Land Cover Change (LULC on stream flow have been assessed in the Black Volta basin using the SWAT model. The spatio-temporal variability of rainfall over the Black Volta was assessed using the Mann-Kendall monotonic trend test and the Sen’s slope for the period 1976–2011. The statistics of the trend test showed that 61.4% of the rain gauges presented an increased precipitation trend whereas the rest of the stations showed a decreased trend. However, the test performed at the 95% confidence interval level showed that the detected trends in the rainfall data were not statistically significant. Land use trends between the year 2000 and 2013 show that within thirteen years, land use classes like bare land, urban areas, water bodies, agricultural lands, deciduous forests and evergreen forests have increased respectively by 67.06%, 33.22%, 7.62%, 29.66%, 60.18%, and 38.38%. Only grass land has decreased by 44.54% within this period. Changes in seasonal stream flow due to LULC were assessed by defining dry and wet seasons. The results showed that from year 2000 to year 2013, the dry season discharge has increased by 6% whereas the discharge of wet season has increased by 1%. The changes in stream flows components such us surface run-off (SURF_Q, lateral flow (LAT_Q and ground water contribution to stream flow (GW_Q and also on evapotranspiration (ET changes due to LULC was evaluated. The results showed that between the year 2000 and 2013, SURF_Q and LAT_Q have respectively increased by 27% and 19% while GW_Q has decreased by 6% while ET has increased by 4.59%. The resultant effects are that the water yield to stream flow has increased by 4%.

  7. DNS of heat transfer in transitional, accelerated boundary layer flow over a flat plate affected by free-stream fluctuations

    International Nuclear Information System (INIS)

    Wissink, Jan G.; Rodi, Wolfgang

    2009-01-01

    Direct numerical simulations (DNS) of flow over and heat transfer from a flat plate affected by free-stream fluctuations were performed. A contoured upper wall was employed to generate a favourable streamwise pressure gradient along a large portion of the flat plate. The free-stream fluctuations originated from a separate LES of isotropic turbulence in a box. In the laminar portions of the accelerating boundary layer flow the formation of streaks was observed to induce an increase in heat transfer by the exchange of hot fluid near the surface of the plate and cold fluid from the free-stream. In the regions where the streamwise pressure gradient was only mildly favourable, intermittent turbulent spots were detected which relaminarised downstream as the streamwise pressure gradient became stronger. The relaminarisation of the turbulent spots was reflected by a slight decrease in the friction coefficient, which converged to its laminar value in the region where the streamwise pressure gradient was strongest.

  8. Effects of watershed land use and geomorphology on stream low flows during severe drought conditions in the southern Blue Ridge Mountains, Georgia and North Carolina

    Science.gov (United States)

    Watershed land use and topographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the relative influences of land use and watershed geomorphic characteristics on low flow variability in the sour...

  9. Efficient Buffer Capacity and Scheduler Setting Computation for Soft Real-Time Stream Processing Applications

    NARCIS (Netherlands)

    Bekooij, Marco; Bekooij, Marco Jan Gerrit; Wiggers, M.H.; van Meerbergen, Jef

    2007-01-01

    Soft real-time applications that process data streams can often be intuitively described as dataflow process networks. In this paper we present a novel analysis technique to compute conservative estimates of the required buffer capacities in such process networks. With the same analysis technique

  10. Hierarchical programming language for modal multi-rate real-time stream processing applications

    NARCIS (Netherlands)

    Geuns, S.J.; Hausmans, J.P.H.M.; Bekooij, Marco Jan Gerrit

    2014-01-01

    Modal multi-rate stream processing applications with real-time constraints which are executed on multi-core embedded systems often cannot be conveniently specified using current programming languages. An important issue is that sequential programming languages do not allow for convenient programming

  11. Unsupervised deep learning for real-time assessment of video streaming services

    NARCIS (Netherlands)

    Torres Vega, M.; Mocanu, D.C.; Liotta, A.

    2017-01-01

    Evaluating quality of experience in video streaming services requires a quality metric that works in real time and for a broad range of video types and network conditions. This means that, subjective video quality assessment studies, or complex objective video quality assessment metrics, which would

  12. Nonlinear analysis of river flow time sequences

    Science.gov (United States)

    Porporato, Amilcare; Ridolfi, Luca

    1997-06-01

    Within the field of chaos theory several methods for the analysis of complex dynamical systems have recently been proposed. In light of these ideas we study the dynamics which control the behavior over time of river flow, investigating the existence of a low-dimension deterministic component. The present article follows the research undertaken in the work of Porporato and Ridolfi [1996a] in which some clues as to the existence of chaos were collected. Particular emphasis is given here to the problem of noise and to nonlinear prediction. With regard to the latter, the benefits obtainable by means of the interpolation of the available time series are reported and the remarkable predictive results attained with this nonlinear method are shown.

  13. Stability of time dependent and spatially varying flows; Proceedings of the Symposium, Hampton, VA, Aug. 19-23, 1985

    International Nuclear Information System (INIS)

    Dwoyer, D.L.; Hussaini, M.Y.

    1987-01-01

    Papers are presented on the application of stability theory to laminar flow control, secondary instabilities in boundary layers, a Floquet analysis of secondary instability in shear flows, and the generation of Tollmien-Schlichting waves by long wavelength free stream disturbances. Also considered are numerical experiments on boundary-layer receptivity, short-scale inviscid instabilities in the flow past surface-mounted obstacles, wave phenomena in a high Reynolds number compressible boundary layer, and instability of time-periodic flows. Other topics include high frequency Rayleigh instability of Stokes layers, stability and resonance in grooved-channel flows, finite length Taylor Couette flow, and vortical structures in the breakdown stage of transition

  14. Real-Time Clinical Decision Support System with Data Stream Mining

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2012-01-01

    Full Text Available This research aims to describe a new design of data stream mining system that can analyze medical data stream and make real-time prediction. The motivation of the research is due to a growing concern of combining software technology and medical functions for the development of software application that can be used in medical field of chronic disease prognosis and diagnosis, children healthcare, diabetes diagnosis, and so forth. Most of the existing software technologies are case-based data mining systems. They only can analyze finite and structured data set and can only work well in their early years and can hardly meet today's medical requirement. In this paper, we describe a clinical-support-system based data stream mining technology; the design has taken into account all the shortcomings of the existing clinical support systems.

  15. Projected effects of Climate-change-induced flow alterations on stream macroinvertebrate abundances.

    Science.gov (United States)

    Kakouei, Karan; Kiesel, Jens; Domisch, Sami; Irving, Katie S; Jähnig, Sonja C; Kail, Jochem

    2018-03-01

    Global change has the potential to affect river flow conditions which are fundamental determinants of physical habitats. Predictions of the effects of flow alterations on aquatic biota have mostly been assessed based on species ecological traits (e.g., current preferences), which are difficult to link to quantitative discharge data. Alternatively, we used empirically derived predictive relationships for species' response to flow to assess the effect of flow alterations due to climate change in two contrasting central European river catchments. Predictive relationships were set up for 294 individual species based on (1) abundance data from 223 sampling sites in the Kinzig lower-mountainous catchment and 67 sites in the Treene lowland catchment, and (2) flow conditions at these sites described by five flow metrics quantifying the duration, frequency, magnitude, timing and rate of flow events using present-day gauging data. Species' abundances were predicted for three periods: (1) baseline (1998-2017), (2) horizon 2050 (2046-2065) and (3) horizon 2090 (2080-2099) based on these empirical relationships and using high-resolution modeled discharge data for the present and future climate conditions. We compared the differences in predicted abundances among periods for individual species at each site, where the percent change served as a proxy to assess the potential species responses to flow alterations. Climate change was predicted to most strongly affect the low-flow conditions, leading to decreased abundances of species up to -42%. Finally combining the response of all species over all metrics indicated increasing overall species assemblage responses in 98% of the studied river reaches in both projected horizons and were significantly larger in the lower-mountainous Kinzig compared to the lowland Treene catchment. Such quantitative analyses of freshwater taxa responses to flow alterations provide valuable tools for predicting potential climate-change impacts on species

  16. Mutual Information Based Dynamic Integration of Multiple Feature Streams for Robust Real-Time LVCSR

    Science.gov (United States)

    Sato, Shoei; Kobayashi, Akio; Onoe, Kazuo; Homma, Shinichi; Imai, Toru; Takagi, Tohru; Kobayashi, Tetsunori

    We present a novel method of integrating the likelihoods of multiple feature streams, representing different acoustic aspects, for robust speech recognition. The integration algorithm dynamically calculates a frame-wise stream weight so that a higher weight is given to a stream that is robust to a variety of noisy environments or speaking styles. Such a robust stream is expected to show discriminative ability. A conventional method proposed for the recognition of spoken digits calculates the weights front the entropy of the whole set of HMM states. This paper extends the dynamic weighting to a real-time large-vocabulary continuous speech recognition (LVCSR) system. The proposed weight is calculated in real-time from mutual information between an input stream and active HMM states in a searchs pace without an additional likelihood calculation. Furthermore, the mutual information takes the width of the search space into account by calculating the marginal entropy from the number of active states. In this paper, we integrate three features that are extracted through auditory filters by taking into account the human auditory system's ability to extract amplitude and frequency modulations. Due to this, features representing energy, amplitude drift, and resonant frequency drifts, are integrated. These features are expected to provide complementary clues for speech recognition. Speech recognition experiments on field reports and spontaneous commentary from Japanese broadcast news showed that the proposed method reduced error words by 9.2% in field reports and 4.7% in spontaneous commentaries relative to the best result obtained from a single stream.

  17. Effects of watershed land use and geomorphology on stream low flows during severe drought conditions in the southern Blue Ridge Mountains, Georgia and North Carolina, United States

    Science.gov (United States)

    Katie Price; C. Jackson; Albert Parker; Trond Reitan; John Dowd; Mike Cyterski

    2011-01-01

    Land use and physiographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the influence of land use and watershed geomorphic characteristics on low-flow variability in the southern Blue Ridge Mountains of North Carolina and Georgia. Ten minute interval discharge data for 35 streams (...

  18. PIV measurements of acoustic and flow-induced vibration in main stream lines

    International Nuclear Information System (INIS)

    Li, Yanrong; Someya, Satoshi; Okamoto, Koji

    2009-01-01

    Systems with closed side-branches are liable to an excitation of sound, as called cavity tone. In this study, flow-induced acoustic resonances of piping systems containing closed side-branches were investigated experimentally. The present investigation on the coaxial closed side-branches is the first rudimentary study to measure the pressure at the downstream side opening of the cavity by microphone and to visualize the fluid flow in the cross-section by using PIV. High-time-resolved PIV has a possibility to analyze the velocity field and the relation between sound propagation and flow field. The fluid flows at different points in the cavity interact with some phase differences and the relation can be clarified. (author)

  19. Persistent effects of wildfire and debris flows on the invertebrate prey base of rainbow trout in Idaho streams

    Science.gov (United States)

    Rosenberger, A.E.; Dunham, J.B.; Buffington, J.M.; Wipfli, M.S.

    2011-01-01

    Wildfire and debris flows are important physical and ecological drivers in headwater streams of western North America. Past research has primarily examined short-term effects of these disturbances; less is known about longer-term impacts. We investigated wildfire effects on the invertebrate prey base for drift-feeding rainbow trout (Oncorhynchus mykiss, Walbaum) in Idaho headwater streams a decade after wildfire. Three stream types with different disturbance histories were examined: 1) unburned, 2) burned, and 3) burned followed by debris flows that reset channel morphology and riparian vegetation. The quantity of macroinvertebrate drift (biomass density) was more variable within than among disturbance categories. Average body weight and taxonomic richness of drift were significantly related to water temperature and influenced by disturbance history. During the autumn sampling period, the amount of terrestrial insects in rainbow trout diets varied with disturbance history and the amount of overhead canopy along the stream banks. Results indicate that there are detectable changes to macroinvertebrate drift and trout diet a decade after wildfire, and that these responses are better correlated with specific characteristics of the stream (water temperature, canopy cover) than with broad disturbance classes.

  20. A real-time remote video streaming platform for ultrasound imaging.

    Science.gov (United States)

    Ahmadi, Mehdi; Gross, Warren J; Kadoury, Samuel

    2016-08-01

    Ultrasound is a viable imaging technology in remote and resources-limited areas. Ultrasonography is a user-dependent skill which depends on a high degree of training and hands-on experience. However, there is a limited number of skillful sonographers located in remote areas. In this work, we aim to develop a real-time video streaming platform which allows specialist physicians to remotely monitor ultrasound exams. To this end, an ultrasound stream is captured and transmitted through a wireless network into remote computers, smart-phones and tablets. In addition, the system is equipped with a camera to track the position of the ultrasound probe. The main advantage of our work is using an open source platform for video streaming which gives us more control over streaming parameters than the available commercial products. The transmission delays of the system are evaluated for several ultrasound video resolutions and the results show that ultrasound videos close to the high-definition (HD) resolution can be received and displayed on an Android tablet with the delay of 0.5 seconds which is acceptable for accurate real-time diagnosis.

  1. Free stream turbulence and density ratio effects on the interaction region of a jet in a cross flow

    Science.gov (United States)

    Wark, C. E.; Foss, J. F.

    1984-01-01

    Jets of low temperature air are introduced into the aft sections of gas turbine combustors for the purpose of cooling the high temperature gases and quenching the combustion reactions. Research studies, motivated by this complex flow field, have been executed by introducing a heated jet into the cross stream of a wind tunnel. The investigation by Kamotani and Greber stands as a prime example of such investigations and it serves as the principal reference for the present study. The low disturbance level of the cross stream, in their study and in similar research investigations, is compatible with an interest in identifying the basic features of this flow field. The influence of the prototypes' strongly disturbed cross flow is not, however, made apparent in these prior investigations.

  2. Change Semantic Constrained Online Data Cleaning Method for Real-Time Observational Data Stream

    Science.gov (United States)

    Ding, Yulin; Lin, Hui; Li, Rongrong

    2016-06-01

    Recent breakthroughs in sensor networks have made it possible to collect and assemble increasing amounts of real-time observational data by observing dynamic phenomena at previously impossible time and space scales. Real-time observational data streams present potentially profound opportunities for real-time applications in disaster mitigation and emergency response, by providing accurate and timeliness estimates of environment's status. However, the data are always subject to inevitable anomalies (including errors and anomalous changes/events) caused by various effects produced by the environment they are monitoring. The "big but dirty" real-time observational data streams can rarely achieve their full potential in the following real-time models or applications due to the low data quality. Therefore, timely and meaningful online data cleaning is a necessary pre-requisite step to ensure the quality, reliability, and timeliness of the real-time observational data. In general, a straightforward streaming data cleaning approach, is to define various types of models/classifiers representing normal behavior of sensor data streams and then declare any deviation from this model as normal or erroneous data. The effectiveness of these models is affected by dynamic changes of deployed environments. Due to the changing nature of the complicated process being observed, real-time observational data is characterized by diversity and dynamic, showing a typical Big (Geo) Data characters. Dynamics and diversity is not only reflected in the data values, but also reflected in the complicated changing patterns of the data distributions. This means the pattern of the real-time observational data distribution is not stationary or static but changing and dynamic. After the data pattern changed, it is necessary to adapt the model over time to cope with the changing patterns of real-time data streams. Otherwise, the model will not fit the following observational data streams, which may led

  3. CHANGE SEMANTIC CONSTRAINED ONLINE DATA CLEANING METHOD FOR REAL-TIME OBSERVATIONAL DATA STREAM

    Directory of Open Access Journals (Sweden)

    Y. Ding

    2016-06-01

    Full Text Available Recent breakthroughs in sensor networks have made it possible to collect and assemble increasing amounts of real-time observational data by observing dynamic phenomena at previously impossible time and space scales. Real-time observational data streams present potentially profound opportunities for real-time applications in disaster mitigation and emergency response, by providing accurate and timeliness estimates of environment’s status. However, the data are always subject to inevitable anomalies (including errors and anomalous changes/events caused by various effects produced by the environment they are monitoring. The “big but dirty” real-time observational data streams can rarely achieve their full potential in the following real-time models or applications due to the low data quality. Therefore, timely and meaningful online data cleaning is a necessary pre-requisite step to ensure the quality, reliability, and timeliness of the real-time observational data. In general, a straightforward streaming data cleaning approach, is to define various types of models/classifiers representing normal behavior of sensor data streams and then declare any deviation from this model as normal or erroneous data. The effectiveness of these models is affected by dynamic changes of deployed environments. Due to the changing nature of the complicated process being observed, real-time observational data is characterized by diversity and dynamic, showing a typical Big (Geo Data characters. Dynamics and diversity is not only reflected in the data values, but also reflected in the complicated changing patterns of the data distributions. This means the pattern of the real-time observational data distribution is not stationary or static but changing and dynamic. After the data pattern changed, it is necessary to adapt the model over time to cope with the changing patterns of real-time data streams. Otherwise, the model will not fit the following observational

  4. Accounting for intracell flow in models with emphasis on water table recharge and stream-aquifer interaction: 1. Problems and concepts

    Science.gov (United States)

    Jorgensen, Donald G.; Signor, Donald C.; Imes, Jeffrey L.

    1989-01-01

    Intracell flow is important in modeling cells that contain both sources and sinks. Special attention is needed if recharge through the water table is a source. One method of modeling multiple sources and sinks is to determine the net recharge per cell. For example, for a model cell containing both a sink and recharge through the water table, the amount of recharge should be reduced by the ratio of the area of influence of the sink within the cell to the area of the cell. The reduction is the intercepted portion of the recharge. In a multilayer model this amount is further reduced by a proportion factor, which is a function of the depth of the flow lines from the water table boundary to the internal sink. A gaining section of a stream is a typical sink. The aquifer contribution to a gaining stream can be conceptualized as having two parts; the first part is the intercepted lateral flow from the water table and the second is the flow across the streambed due to differences in head between the water level in the stream and the aquifer below. The amount intercepted is a function of the geometry of the cell, but the amount due to difference in head across the stream bed is largely independent of cell geometry. A discharging well can intercept recharge through the water table within a model cell. The net recharge to the cell would be reduced in proportion to the area of influence of the well within the cell. The area of influence generally changes with time. Thus the amount of intercepted recharge and net recharge may not be constant with time. During periods when the well is not discharging there will be no intercepted recharge even though the area of influence from previous pumping may still exist. The reduction of net recharge per cell due to internal interception of flow will result in a model-calculated mass balance less than the prototype. Additionally the “effective transmissivity” along the intercell flow paths may be altered when flow paths are occupied by

  5. Geomorphic, flood, and groundwater-flow characteristics of Bayfield Peninsula streams, Wisconsin, and implications for brook-trout habitat

    Science.gov (United States)

    Fitzpatrick, Faith A.; Peppler, Marie C.; Saad, David A.; Pratt, Dennis M.; Lenz, Bernard N.

    2015-01-01

    In 2002–03, the U.S. Geological Survey conducted a study of the geomorphic, flood, and groundwater-flow characteristics of five Bayfield Peninsula streams, Wisconsin (Cranberry River, Bark River, Raspberry River, Sioux River, and Whittlesey Creek) to determine the physical limitations for brook-trout habitat. The goals of the study were threefold: (1) to describe geomorphic characteristics and processes, (2) to determine how land-cover characteristics affect flood peaks, and (3) to determine how regional groundwater flow patterns affect base flow.

  6. Design for real-time data acquisition based on streaming technology

    International Nuclear Information System (INIS)

    Nakanishi, Hideya; Kojima, Mamoru

    2001-04-01

    For the LHD project a long-pulse plasma experiment of one-hour duration is planned. In this quasi steady-state operation, the data acquisition system will be required to continuously transfer the diagnostic data from the digitizer front-end and display them in real-time. The Compact PCI standard is used to replace the conventional CAMAC digitizers in LHD, because it provides good functionality for real-time data streaming and also a connectivity with modern PC technology. The digitizer scheme, interface to the host computer, adoption of data compression, and downstream applications are discussed in detail to design and implement this new real-time data streaming system for LHD plasma diagnostics. (author)

  7. Instream flow characterization of upper Salmon River basin streams, central Idaho, 2004

    Science.gov (United States)

    Maret, Terry R.; Hortness, Jon E.; Ott, Douglas S.

    2005-01-01

    Anadromous fish populations in the Columbia River Basin have plummeted in the last 100 years. This severe decline led to Federal listing of Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) stocks as endangered or threatened under the Endangered Species Act (ESA) in the 1990s. Historically, the upper Salmon River Basin (upstream of the confluence with the Pahsimeroi River) in Idaho provided migration corridors and significant habitat for these ESA-listed species, in addition to the ESA-listed bull trout (Salvelinus confluentus). Human development has modified the original streamflow conditions in many streams in the upper Salmon River Basin. Summer streamflow modifications resulting from irrigation practices, have directly affected quantity and quality of fish habitat and also have affected migration and (or) access to suitable spawning and rearing habitat for these fish. As a result of these ESA listings and Action 149 of the Federal Columbia River Power System Biological Opinion of 2000, the Bureau of Reclamation was tasked to conduct streamflow characterization studies in the upper Salmon River Basin to clearly define habitat requirements for effective species management and habitat restoration. These studies include collection of habitat and streamflow information for the Physical Habitat Simulation System model, a widely applied method to determine relations between habitat and discharge requirements for various fish species and life stages. Model results can be used by resource managers to guide habitat restoration efforts by evaluating potential fish habitat and passage improvements by increasing streamflow. In 2004, instream flow characterization studies were completed on Salmon River and Beaver, Pole, Champion, Iron, Thompson, and Squaw Creeks. Continuous streamflow data were recorded upstream of all diversions on Salmon River and Pole, Iron, Thompson, and Squaw Creeks. In addition, natural summer streamflows were

  8. Stream flow regime of springs in the Mantiqueira Mountain Range region, Minas Gerais State

    Directory of Open Access Journals (Sweden)

    Alisson Souza de Oliveira

    2014-09-01

    Full Text Available The stream flow regime of four springs located in the Mantiqueira Mountain Range region (MG was evaluated and correlated to the respective recharge area, relief characteristics, land cover and physical and hydrologic soil characteristics. The streamflow regime was characterized by monitoring of discharges, calculating the surface runoff and specific discharge and by modeling the discharge over the recession period using the Maillet method. As all recharge areas have similar relief the effect of it on the streamflow was not possible to identify. Analysis included determining the effect of drainage area size, soil characteristics and land cover on the indicators of the streamflow regime. Size of the recharge area had a positive influence on the indicators mean discharge and surface runoff volume and on the regulation of the streamflow regime (springs L4 and L1. The spring under the smallest area of influence provided the worst results for the above mentioned indicators (spring L3. The effect of forest cover (natural and planted, associated with soil characteristics, was evidenced by the indicators surface runoff (in depth and specific yield, both independent of the recharge area size (springs L4 and L2. The interaction of area size, soil characteristics and forest cover (natural and planted provided the best results for all indicators of streamflow regime in the springs studied in the Mantiqueira Mountain Range (spring L4.

  9. Importance of vegetation, topography and flow paths for water transit times of base flow in alpine headwater catchments

    Directory of Open Access Journals (Sweden)

    M. H. Mueller

    2013-04-01

    Full Text Available The mean transit time (MTT of water in a catchment gives information about storage, flow paths, sources of water and thus also about retention and release of solutes in a catchment. To our knowledge there are only a few catchment studies on the influence of vegetation cover changes on base flow MTTs. The main changes in vegetation cover in the Swiss Alps are massive shrub encroachment and forest expansion into formerly open habitats. Four small and relatively steep headwater catchments in the Swiss Alps (Ursern Valley were investigated to relate different vegetation cover to water transit times. Time series of water stable isotopes were used to calculate MTTs. The high temporal variation of the stable isotope signals in precipitation was strongly dampened in stream base flow samples. MTTs of the four catchments were 70 to 102 weeks. The strong dampening of the stable isotope input signal as well as stream water geochemistry points to deeper flow paths and mixing of waters of different ages at the catchments' outlets. MTTs were neither related to topographic indices nor vegetation cover. The major part of the quickly infiltrating precipitation likely percolates through fractured and partially karstified deeper rock zones, which increases the control of bedrock flow paths on MTT. Snow accumulation and the timing of its melt play an important role for stable isotope dynamics during spring and early summer. We conclude that, in mountainous headwater catchments with relatively shallow soil layers, the hydrogeological and geochemical patterns (i.e. geochemistry, porosity and hydraulic conductivity of rocks and snow dynamics influence storage, mixing and release of water in a stronger way than vegetation cover or topography do.

  10. Study of stream wise transverse magnetic fluid flow with heat transfer around an obstacle embedded in a porous medium

    Energy Technology Data Exchange (ETDEWEB)

    Rashidi, S. [Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad 91775-1111 (Iran, Islamic Republic of); Dehghan, M. [Department of Mechanical Engineering, Semnan University, P.O. Box: 35196-45399, Semnan (Iran, Islamic Republic of); Ellahi, R., E-mail: rellahi@engr.ucr.edu [Department of Mathematics and Statistics, FBAS, IIUI, 44000 Islamabad (Pakistan); Department of Mechanical Engineering, Bourns Hall, University of California, Riverside, CA 92521 (United States); Riaz, M. [Department of QEC, National Defense University, E-9 Sector, 44000 Islamabad (Pakistan); Jamal-Abad, M.T. [Department of Mechanical Engineering, Semnan University, P.O. Box: 35196-45399, Semnan (Iran, Islamic Republic of)

    2015-03-15

    A mathematical model for two-dimensional fluid flow under the influence of stream wise transverse magnetic fields in laminar regime is simulated in this study. Heat transfer past a square diamond shaped porous obstacle is also taken into account. The attention is focused to investigate the effects of intensity and direction of magnetic field, Darcy and Reynolds numbers on the mechanism of convective heat transfer and flow structures. The Darcy–Brinkman–Forchheimer model along with the Maxwell equations is used. The nonlinear coupled equations using a finite volume approach (FVA) are solved numerically. The calculations are performed for different governing parameters such as Reynolds number, Nusselt number, Stuart number and Prandtl Number. The physical interpretation of velocity and isothermal contours is assigned through graphs. It is shown that the effects of a transverse magnetic field on flow behavior and heat transfer mechanism are more than that of the stream wise magnetic field. The configuration of streamlines and vorticity contours phenomena are also presented for porous diamond obstacle. Comparison of the numerical solutions with existing literature is also made. - Highlights: • This paper analyses two-dimensional fluid flow under the influence of stream wise transverse magnetic field. • Heat transfer past a square diamond shaped porous obstacle is taken into account. • The Darcy–Brinkman–Forchheimer model is used. • Finite volume approach is used to find numerical solutions. • The configuration of streamlines and vorticity contours phenomena are presented through graphs.

  11. Notes on the Vegetation of the Fast-flowing Streams in Peninsular Thailand, the Tropical Mainland of South East Asia

    Directory of Open Access Journals (Sweden)

    Milica Stankovic

    2013-12-01

    Full Text Available The species composition and structure of the plant communities along and in the fast-flowing streams on different bedrock types of the tropical mainland South-East Asia were investigated. The study was carried out in Peninsular Thailand, on the Nakhon Si Thammarat mountain range. A total number of 14 plots were placed within the five selected streams where vascular plants species had been collected, starting from November 2010 until July 2012. The estimation of the species was calculated by computer program EstimateS, and in order to distinguish plant communities, a cluster analysis was performed. A total number of 109 species of vascular plants has been recorded, with 59 species in the granite and 60 in the calcareous bedrock streams. There were four types of plant communities that had were categorized; of which three types occurred in the granitic bedrock streams and the other could be seen exclusively in the calcareous bedrock. It is convinced that the types of the bedrock as well as the topographic features of the streams might have major impact on the characterization of the plant communities.

  12. Irrigant flow during photon-induced photoacoustic streaming (PIPS) using Particle Image Velocimetry (PIV).

    Science.gov (United States)

    Koch, Jon D; Jaramillo, David E; DiVito, Enrico; Peters, Ove A

    2016-03-01

    This study aimed to compare fluid movements generated from photon-induced photoacoustic streaming (PIPS) and passive ultrasonic irrigation (PUI). Particle Image Velocimetry (PIV) was performed using 6-μm melamine spheres in water. Measurement areas were 3-mm-long sections of the canal in the coronal, midroot and apical regions for PIPS (erbium/yttrium-aluminium garnet (Er:YAG) laser set at 15 Hz with 20 mJ), or passive ultrasonic irrigation (PUI, non-cutting insert at 30% unit power) was performed in simulated root canals prepared to an apical size #30/0.04 taper. Fluid movement was analysed directly subjacent to the apical ends of ultrasonic insert or fiber optic tips as well as at midroot and apically. During PUI, measured average velocities were around 0.03 m/s in the immediate vicinity of the sides and tip of the ultrasonic file. Speeds decayed to non-measureable values at a distance of about 2 mm from the sides and tip. During PIPS, typical average speeds were about ten times higher than those measured for PUI, and they were measured throughout the length of the canal, at distances up to 20 mm away. PIPS caused higher average fluid speeds when compared to PUI, both close and distant from the instrument. The findings of this study could be relevant to the debriding and disinfecting stage of endodontic therapy. Irrigation enhancement beyond needle irrigation is relevant to more effectively eradicate microorganisms from root canal systems. PIPS may be an alternative approach due to its ability to create high streaming velocities further away from the activation source compared to ultrasonic activation.

  13. Saturation flow versus green time at two-stage signal controlled intersections

    Directory of Open Access Journals (Sweden)

    A. Boumediene

    2009-12-01

    Full Text Available Intersections are the key components of road networks considerably affecting capacity. As flow levels and experience have increased over the years, methods and means have been developed to cope with growing demand for traffic at road junctions. Among various traffic control devices and techniques developed to cope with conflicting movements, traffic signals create artificial gaps to accommodate the impeded traffic streams. The majority of parameters that govern signalised intersection control and operations such as a degree of saturation, delays, queue lengths, the level of service etc. are very sensitive to saturation flow. Therefore, it is essential to reliably evaluate saturation flow for correctly setting traffic signals to avoid unnecessary delays and conflicts. Generally, almost all guidelines support the constancy of saturation flow irrespective of green time duration. This paper presents the results of field studies carried out to enable the performance of signalised intersections to be compared at different green time durations. It was found that saturation flow decreased slightly with growing green time. Reduction corresponded to between 2 and 5 pcus/gh per second of green time. However, the analyses of the discharge rate during the successive time intervals of 6-seconds showed a substantial reduction of 10% to 13% in saturation flow levels after 36 seconds of green time compared to those relating to 6–36 seconds range. No reduction in saturation flow levels was detected at the sites where only green periods of 44 seconds or less were implemented.

  14. Cytoplasmic Streaming in the Drosophila Oocyte.

    Science.gov (United States)

    Quinlan, Margot E

    2016-10-06

    Objects are commonly moved within the cell by either passive diffusion or active directed transport. A third possibility is advection, in which objects within the cytoplasm are moved with the flow of the cytoplasm. Bulk movement of the cytoplasm, or streaming, as required for advection, is more common in large cells than in small cells. For example, streaming is observed in elongated plant cells and the oocytes of several species. In the Drosophila oocyte, two stages of streaming are observed: relatively slow streaming during mid-oogenesis and streaming that is approximately ten times faster during late oogenesis. These flows are implicated in two processes: polarity establishment and mixing. In this review, I discuss the underlying mechanism of streaming, how slow and fast streaming are differentiated, and what we know about the physiological roles of the two types of streaming.

  15. Time-averaged second-order pressure and velocity measurements in a pressurized oscillating flow prime mover

    Energy Technology Data Exchange (ETDEWEB)

    Paridaens, Richard [DynFluid, Arts et Metiers, 151 boulevard de l' Hopital, Paris (France); Kouidri, Smaine [LIMSI-CNRS, Orsay Cedex (France)

    2016-11-15

    Nonlinear phenomena in oscillating flow devices cause the appearance of a relatively minor secondary flow known as acoustic streaming, which is superimposed on the primary oscillating flow. Knowledge of control parameters, such as the time-averaged second-order velocity and pressure, would elucidate the non-linear phenomena responsible for this part of the decrease in the system's energetic efficiency. This paper focuses on the characterization of a travelling wave oscillating flow engine by measuring the time-averaged second order pressure and velocity. Laser Doppler velocimetry technique was used to measure the time-averaged second-order velocity. As streaming is a second-order phenomenon, its measurement requires specific settings especially in a pressurized device. Difficulties in obtaining the proper settings are highlighted in this study. The experiments were performed for mean pressures varying from 10 bars to 22 bars. Non-linear effect does not constantly increase with pressure.

  16. An explicit multi-time-stepping algorithm for aerodynamic flows

    OpenAIRE

    Niemann-Tuitman, B.E.; Veldman, A.E.P.

    1997-01-01

    An explicit multi-time-stepping algorithm with applications to aerodynamic flows is presented. In the algorithm, in different parts of the computational domain different time steps are taken, and the flow is synchronized at the so-called synchronization levels. The algorithm is validated for aerodynamic turbulent flows. For two-dimensional flows speedups in the order of five with respect to single time stepping are obtained.

  17. Boundary Layer Flow and Heat Transfer with Variable Fluid Properties on a Moving Flat Plate in a Parallel Free Stream

    Directory of Open Access Journals (Sweden)

    Norfifah Bachok

    2012-01-01

    Full Text Available The steady boundary layer flow and heat transfer of a viscous fluid on a moving flat plate in a parallel free stream with variable fluid properties are studied. Two special cases, namely, constant fluid properties and variable fluid viscosity, are considered. The transformed boundary layer equations are solved numerically by a finite-difference scheme known as Keller-box method. Numerical results for the flow and the thermal fields for both cases are obtained for various values of the free stream parameter and the Prandtl number. It is found that dual solutions exist for both cases when the fluid and the plate move in the opposite directions. Moreover, fluid with constant properties shows drag reduction characteristics compared to fluid with variable viscosity.

  18. Numerical study of unsteady MHD oblique stagnation point flow and heat transfer due to an oscillating stream

    Science.gov (United States)

    Javed, T.; Ghaffari, A.; Ahmad, H.

    2016-05-01

    The unsteady stagnation point flow impinging obliquely on a flat plate in presence of a uniform applied magnetic field due to an oscillating stream has been studied. The governing partial differential equations are transformed into dimensionless form and the stream function is expressed in terms of Hiemenz and tangential components. The dimensionless partial differential equations are solved numerically by using well-known implicit finite difference scheme named as Keller-box method. The obtained results are compared with those available in the literature. It is observed that the results are in excellent agreement with the previous studies. The effects of pertinent parameters involved in the problem namely magnetic parameter, Prandtl number and impinging angle on flow and heat transfer characteristics are illustrated through graphs. It is observed that the influence of magnetic field strength increases the fluid velocity and by the increase of obliqueness parameter, the skin friction increases.

  19. Stream II-V5: Revision Of Stream II-V4 To Account For The Effects Of Rainfall Events

    International Nuclear Information System (INIS)

    Chen, K.

    2010-01-01

    STREAM II-V4 is the aqueous transport module currently used by the Savannah River Site emergency response Weather Information Display (WIND) system. The transport model of the Water Quality Analysis Simulation Program (WASP) was used by STREAM II to perform contaminant transport calculations. WASP5 is a US Environmental Protection Agency (EPA) water quality analysis program that simulates contaminant transport and fate through surface water. STREAM II-V4 predicts peak concentration and peak concentration arrival time at downstream locations for releases from the SRS facilities to the Savannah River. The input flows for STREAM II-V4 are derived from the historical flow records measured by the United States Geological Survey (USGS). The stream flow for STREAM II-V4 is fixed and the flow only varies with the month in which the releases are taking place. Therefore, the effects of flow surge due to a severe storm are not accounted for by STREAM II-V4. STREAM II-V4 has been revised to account for the effects of a storm event. The steps used in this method are: (1) generate rainfall hyetographs as a function of total rainfall in inches (or millimeters) and rainfall duration in hours; (2) generate watershed runoff flow based on the rainfall hyetographs from step 1; (3) calculate the variation of stream segment volume (cross section) as a function of flow from step 2; (4) implement the results from steps 2 and 3 into the STREAM II model. The revised model (STREAM II-V5) will find the proper stream inlet flow based on the total rainfall and rainfall duration as input by the user. STREAM II-V5 adjusts the stream segment volumes (cross sections) based on the stream inlet flow. The rainfall based stream flow and the adjusted stream segment volumes are then used for contaminant transport calculations.

  20. Effective diffusion in time-periodic linear planar flow

    International Nuclear Information System (INIS)

    Indeikina, A.; Chang, H.

    1993-01-01

    It is shown that when a point source of solute is inserted into a time-periodic, unbounded linear planar flow, the large-time, time-average transport of the solute can be described by classical anisotropic diffusion with constant effective diffusion tensors. For a given vorticity and forcing period, elongational flow is shown to be the most dispersive followed by simple shear and rotational flow. Large-time diffusivity along the major axis of the time-average concentration ellipse, whose alignment is predicted from the theory, is shown to increase with vorticity for all flows and decrease with increasing forcing frequency for elongational flow and simple shear. For the interesting case of rotational flow, there exist discrete resonant frequencies where the time-average major diffusivity reaches local maxima equal to the time-average steady flow case with zero forcing frequency

  1. Structure analysis of bubble driven flow by time-resolved PIV and POD techniques

    International Nuclear Information System (INIS)

    Kim, Hyun Dong; Yi, Seung Jae; Kim, Jong Wook; Kim, Kyung Chun

    2010-01-01

    In this paper, the recirculation flow motion and turbulence characteristics of liquid flow driven by air bubble stream in a rectangular water tank are studied. The time-resolved Particle Image Velocimetry (PIV) technique is adopted for the quantitative visualization and analysis. 532nm Diode CW laser is used for illumination and orange fluorescent (λex = 540nm, λem = 584nm) particle images are acquired by a 1280X1024 high-speed camera. To obtain clean particle images, 545nm long pass optical filter and an image intensifier are employed and the flow rate of compressed air is 3/min at 0.5MPa. The recirculation and mixing flow field is further investigated by timeresolved Proper Orthogonal Decomposition (POD) analysis technique. It is observed that the large scale recirculation resulting from the interaction between rising bubble stream and side wall is the most dominant flow structure and there are small scale vortical structures moving along with the large scale recirculation flow. It is also verified that the sum of 20 modes of velocity field has about 67.4% of total turbulent energy

  2. Instream flow characterization of Upper Salmon River basin streams, central Idaho, 2005

    Science.gov (United States)

    Maret, Terry R.; Hortness, Jon E.; Ott, Douglas S.

    2006-01-01

    Anadromous fish populations in the Columbia River Basin have plummeted in the last 100 years. This severe decline led to Federal listing of Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) stocks as endangered or threatened under the Endangered Species Act (ESA) in the 1990s. Historically, the upper Salmon River Basin (upstream of the confluence with the Pahsimeroi River) in Idaho provided migration corridors and significant habitat for these ESA-listed species, in addition to the ESA-listed bull trout (Salvelinus confluentus). Human development has modified the original streamflow conditions in many streams in the upper Salmon River Basin. Summer streamflow modifications resulting from irrigation practices, have directly affected quantity and quality of fish habitat and also have affected migration and (or) access to suitable spawning and rearing habitat for these fish. As a result of these ESA listings and Action 149 of the Federal Columbia River Power System Biological Opinion of 2000, the Bureau of Reclamation was tasked to conduct streamflow characterization studies in the upper Salmon River Basin to clearly define habitat requirements for effective species management and habitat restoration. These studies include collection of habitat and streamflow information for the Physical Habitat Simulation System (PHABSIM) model, a widely applied method to determine relations between habitat and discharge requirements for various fish species and life stages. Model simulation results can be used by resource managers to guide habitat restoration efforts by evaluating potential fish habitat and passage improvements by increasing or decreasing streamflow. In 2005, instream flow characterization studies were completed on Big Boulder, Challis, Bear, Mill, and Morgan Creeks. Continuous streamflow data were recorded upstream of all diversions on Big Boulder. Instantaneous measurements of discharge were also made at selected sites. In

  3. A distributed approach for optimizing cascaded classifier topologies in real-time stream mining systems.

    Science.gov (United States)

    Foo, Brian; van der Schaar, Mihaela

    2010-11-01

    In this paper, we discuss distributed optimization techniques for configuring classifiers in a real-time, informationally-distributed stream mining system. Due to the large volume of streaming data, stream mining systems must often cope with overload, which can lead to poor performance and intolerable processing delay for real-time applications. Furthermore, optimizing over an entire system of classifiers is a difficult task since changing the filtering process at one classifier can impact both the feature values of data arriving at classifiers further downstream and thus, the classification performance achieved by an ensemble of classifiers, as well as the end-to-end processing delay. To address this problem, this paper makes three main contributions: 1) Based on classification and queuing theoretic models, we propose a utility metric that captures both the performance and the delay of a binary filtering classifier system. 2) We introduce a low-complexity framework for estimating the system utility by observing, estimating, and/or exchanging parameters between the inter-related classifiers deployed across the system. 3) We provide distributed algorithms to reconfigure the system, and analyze the algorithms based on their convergence properties, optimality, information exchange overhead, and rate of adaptation to non-stationary data sources. We provide results using different video classifier systems.

  4. Modeling the time--varying subjective quality of HTTP video streams with rate adaptations.

    Science.gov (United States)

    Chen, Chao; Choi, Lark Kwon; de Veciana, Gustavo; Caramanis, Constantine; Heath, Robert W; Bovik, Alan C

    2014-05-01

    Newly developed hypertext transfer protocol (HTTP)-based video streaming technologies enable flexible rate-adaptation under varying channel conditions. Accurately predicting the users' quality of experience (QoE) for rate-adaptive HTTP video streams is thus critical to achieve efficiency. An important aspect of understanding and modeling QoE is predicting the up-to-the-moment subjective quality of a video as it is played, which is difficult due to hysteresis effects and nonlinearities in human behavioral responses. This paper presents a Hammerstein-Wiener model for predicting the time-varying subjective quality (TVSQ) of rate-adaptive videos. To collect data for model parameterization and validation, a database of longer duration videos with time-varying distortions was built and the TVSQs of the videos were measured in a large-scale subjective study. The proposed method is able to reliably predict the TVSQ of rate adaptive videos. Since the Hammerstein-Wiener model has a very simple structure, the proposed method is suitable for online TVSQ prediction in HTTP-based streaming.

  5. A reference web architecture and patterns for real-time visual analytics on large streaming data

    Science.gov (United States)

    Kandogan, Eser; Soroker, Danny; Rohall, Steven; Bak, Peter; van Ham, Frank; Lu, Jie; Ship, Harold-Jeffrey; Wang, Chun-Fu; Lai, Jennifer

    2013-12-01

    Monitoring and analysis of streaming data, such as social media, sensors, and news feeds, has become increasingly important for business and government. The volume and velocity of incoming data are key challenges. To effectively support monitoring and analysis, statistical and visual analytics techniques need to be seamlessly integrated; analytic techniques for a variety of data types (e.g., text, numerical) and scope (e.g., incremental, rolling-window, global) must be properly accommodated; interaction, collaboration, and coordination among several visualizations must be supported in an efficient manner; and the system should support the use of different analytics techniques in a pluggable manner. Especially in web-based environments, these requirements pose restrictions on the basic visual analytics architecture for streaming data. In this paper we report on our experience of building a reference web architecture for real-time visual analytics of streaming data, identify and discuss architectural patterns that address these challenges, and report on applying the reference architecture for real-time Twitter monitoring and analysis.

  6. Evaluation of spatial plan in controlling stream flow rate in Wakung Watershed, Pemalang, Central Java, Indonesia

    Science.gov (United States)

    Anwar, Y.; Setyasih, I.; Setiawan, M. A.; Christanto, N.

    2018-04-01

    Evaluation study for such a regional spatial plan (RTRW) in Indonesia has not been evaluated for its effectiveness in controlling the surface run off that contributed to streamflow. This necessity can be accomplishsed by applying a modeling approach, such as Soil Water Assessment Tool (SWAT). The objectives of this research are 1) to simulate the streamflow of Wakung watershed based on actual landuse, 2) to predict streamflow of Wakung watershed based on RTRW, and 3) to evaluate the effectiveness of the RTRW of Pemalang District in controling streamflow rate at Wakung Watershed. ArcSWAT model was used to determine the erosion rate prediction. The model was then calibrated by using SWATCUP. Model performance were tested by using R2 and ENS. The calibration and validation results showed that R2 and ENS (monthly) > 0.5. The result of SWAT simulation in Wakung sub-watershed reaching 161 - 4950 m3/s/years for W-A scenario (actual landuse and weather data of 2013), for scenario W-R (RTRW and weather data of 2013), 330 - 4919 m3/s/year. The comparison between actual and spatial plan land use data for stream flow is showing that the W-A scenario is lower than the W-R scenario in 19 sub watersheds. This is because there are many plans for adding land use for urban and intensive horticulture land in areas with steep slopes (> 25%). This condition is caused by the demands of fulfilling the needs of settlement and food for people in the Wakung watershed.

  7. Sound stream segregation: a neuromorphic approach to solve the "cocktail party problem" in real-time.

    Science.gov (United States)

    Thakur, Chetan Singh; Wang, Runchun M; Afshar, Saeed; Hamilton, Tara J; Tapson, Jonathan C; Shamma, Shihab A; van Schaik, André

    2015-01-01

    The human auditory system has the ability to segregate complex auditory scenes into a foreground component and a background, allowing us to listen to specific speech sounds from a mixture of sounds. Selective attention plays a crucial role in this process, colloquially known as the "cocktail party effect." It has not been possible to build a machine that can emulate this human ability in real-time. Here, we have developed a framework for the implementation of a neuromorphic sound segregation algorithm in a Field Programmable Gate Array (FPGA). This algorithm is based on the principles of temporal coherence and uses an attention signal to separate a target sound stream from background noise. Temporal coherence implies that auditory features belonging to the same sound source are coherently modulated and evoke highly correlated neural response patterns. The basis for this form of sound segregation is that responses from pairs of channels that are strongly positively correlated belong to the same stream, while channels that are uncorrelated or anti-correlated belong to different streams. In our framework, we have used a neuromorphic cochlea as a frontend sound analyser to extract spatial information of the sound input, which then passes through band pass filters that extract the sound envelope at various modulation rates. Further stages include feature extraction and mask generation, which is finally used to reconstruct the targeted sound. Using sample tonal and speech mixtures, we show that our FPGA architecture is able to segregate sound sources in real-time. The accuracy of segregation is indicated by the high signal-to-noise ratio (SNR) of the segregated stream (90, 77, and 55 dB for simple tone, complex tone, and speech, respectively) as compared to the SNR of the mixture waveform (0 dB). This system may be easily extended for the segregation of complex speech signals, and may thus find various applications in electronic devices such as for sound segregation and

  8. Predicted macroinvertebrate response to water diversion from a montane stream using two-dimensional hydrodynamic models and zero flow approximation

    Science.gov (United States)

    Holmquist, Jeffrey G.; Waddle, Terry J.

    2013-01-01

    We used two-dimensional hydrodynamic models for the assessment of water diversion effects on benthic macroinvertebrates and associated habitat in a montane stream in Yosemite National Park, Sierra Nevada Mountains, CA, USA. We sampled the macroinvertebrate assemblage via Surber sampling, recorded detailed measurements of bed topography and flow, and coupled a two-dimensional hydrodynamic model with macroinvertebrate indicators to assess habitat across a range of low flows in 2010 and representative past years. We also made zero flow approximations to assess response of fauna to extreme conditions. The fauna of this montane reach had a higher percentage of Ephemeroptera, Plecoptera, and Trichoptera (%EPT) than might be expected given the relatively low faunal diversity of the study reach. The modeled responses of wetted area and area-weighted macroinvertebrate metrics to decreasing discharge indicated precipitous declines in metrics as flows approached zero. Changes in area-weighted metrics closely approximated patterns observed for wetted area, i.e., area-weighted invertebrate metrics contributed relatively little additional information above that yielded by wetted area alone. Loss of habitat area in this montane stream appears to be a greater threat than reductions in velocity and depth or changes in substrate, and the modeled patterns observed across years support this conclusion. Our models suggest that step function losses of wetted area may begin when discharge in the Merced falls to 0.02 m3/s; proportionally reducing diversions when this threshold is reached will likely reduce impacts in low flow years.

  9. Investigation of technology for the monitoring of UF6 mass flow in UF6 streams diluted with H2

    International Nuclear Information System (INIS)

    Baker, O.J.; Cooley, J.N.; Hewgley, W.A.; Moran, B.W.; Swindle, D.W. Jr.

    1986-12-01

    The applicability, availability, and effectiveness of gas flow meters are assessed as a means for verifying the mass flows of pure UF 6 streams diluted with a carrier gas. The initial survey identified the orifice, pitot tube, thermal, vortex shedding, and vortex precession (swirl) meters as promising for the intended use. Subsequent assessments of these flow meters revealed that two - the orifice meter and the pitot tube meter - are the best choices for the proposed applications: the first is recommended for low velocity gas, small diameter piping; the latter, for high velocity gas, large diameter piping. Final selection of the gas flow meters should be based on test loop evaluations in which the proposed meters are subjected to gas flows, temperatures, and pressures representative of those expected in service. Known instruments are evaluated that may be applicable to the measurement of uranium or UF 6 concentration in a UF 6 - H 2 process stream at an aerodynamic enrichment plant. Of the six procedures evaluated, four have been used for process monitoring in a UF 6 environment: gas mass spectrometry, infrared-ultraviolet-visible spectrophotometry, gas chromatography, and acoustic gas analysis. The remaining two procedures, laser fluorimetry and atomic absorption spectroscopy, would require significant development work before they could be used for process monitoring. Infrared-ultravioloet-visible spectrophotometry is judged to be the best procedure currently available to perform the required measurement

  10. Data Centric Sensor Stream Reduction for Real-Time Applications in Wireless Sensor Networks

    Science.gov (United States)

    Aquino, Andre Luiz Lins; Nakamura, Eduardo Freire

    2009-01-01

    This work presents a data-centric strategy to meet deadlines in soft real-time applications in wireless sensor networks. This strategy considers three main aspects: (i) The design of real-time application to obtain the minimum deadlines; (ii) An analytic model to estimate the ideal sample size used by data-reduction algorithms; and (iii) Two data-centric stream-based sampling algorithms to perform data reduction whenever necessary. Simulation results show that our data-centric strategies meet deadlines without loosing data representativeness. PMID:22303145

  11. Real-time 2-D Phased Array Vector Flow Imaging

    DEFF Research Database (Denmark)

    Holbek, Simon; Hansen, Kristoffer Lindskov; Fogh, Nikolaj

    2018-01-01

    Echocardiography examination of the blood flow is currently either restricted to 1-D techniques in real-time or experimental off-line 2-D methods. This paper presents an implementation of transverse oscillation for real-time 2-D vector flow imaging (VFI) on a commercial BK Ultrasound scanner....... A large field-of-view (FOV) sequence for studying flow dynamics at 11 frames per second (fps) and a sequence for studying peak systolic velocities (PSV) with a narrow FOV at 36 fps were validated. The VFI sequences were validated in a flow-rig with continuous laminar parabolic flow and in a pulsating flow...

  12. Evaluation of stream flow effects on smolt survival in the Yakima River Basin, Washington, 2012-2014

    Science.gov (United States)

    Courter, Ian; Garrison, Tommy; Kock, Tobias J.; Perry, Russell W.

    2015-01-01

    The influence of stream flow on survival of emigrating juvenile (smolts) Pacific salmon Oncorhynchus spp. and steelhead trout O. mykiss is of key management interest. However, few studies have quantified flow effects on smolt migration survival, and available information does not indicate a consistent flow-survival relationship within the typical range of flows under management control. It is hypothesized that smolt migration and dam passage survival are positively correlated with stream flow because higher flows increase migration rates, potentially reducing exposure to predation, and reduce delays in reservoirs. However, available empirical data are somewhat equivocal concerning the influence of flow on smolt survival and the underlying mechanisms driving this relationship. Stream flow effects on survival of emigrating anadromous salmonids in the Yakima Basin have concerned water users and fisheries managers for over 20 years, and previous studies do not provide sufficient information at the resolution necessary to inform water operations, which typically occur on a small spatiotemporal scale. Using a series of controlled flow releases from 2012-2014, combined with radio telemetry, we quantified the relationship between flow and smolt survival from Roza Dam 208 km downstream to the Yakima River mouth, as well as for specific routes of passage at Roza Dam. A novel multistate mark-recapture model accounted for weekly variation in flow conditions experienced by radio-tagged fish. Groups of fish were captured and radio-tagged at Roza Dam and released at two locations, upstream at the Big Pines Campground (river kilometer [rkm] 211) and downstream in the Roza Dam tailrace (rkm 208). A total of 904 hatchery-origin yearling Chinook salmon O. tshawytscha were captured in the Roza Dam fish bypass, radio-tagged and released upstream of Roza Dam. Two hundred thirty seven fish were released in the tailrace of Roza Dam. Fish released in the tailrace of Roza Dam were tagged

  13. On semi-inverse solutions for the time-dependent flows of a second-grade fluid

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available This paper deals with analytical solutions for the time-dependent equations arising in a second-grade fluid. The solutions have been developed by assuming certain forms of the stream function. Expressions for velocity components are obtained for flows in plane polar, axisymmetric cylindrical, and axisymmetric spherical polar coordinates. The obtained solutions are compared with existing results.

  14. Quantification of complex blood flow using real-time in vivo vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Haugaard, Per

    2010-01-01

    A quantitative method for distinguishing complex from non-complex flow patterns in ultrasound is presented. A new commercial BK Medical ultrasound scanner uses the Transverse Oscillation vector flow technique for visualising flow patterns in real-time. In vivo vector flow data of the blood flow...... patterns of the common carotid artery and the carotid bulb were obtained simultaneously as the basis for quantifying complex flow. The carotid bifurcation of two healthy volunteers were scanned. The presence of complex flow patterns from eight cardiac cycles were evaluated by three experts in medical...... for automatic detection of complex flow patterns....

  15. Real-Time Earthquake Intensity Estimation Using Streaming Data Analysis of Social and Physical Sensors

    Science.gov (United States)

    Kropivnitskaya, Yelena; Tiampo, Kristy F.; Qin, Jinhui; Bauer, Michael A.

    2017-06-01

    Earthquake intensity is one of the key components of the decision-making process for disaster response and emergency services. Accurate and rapid intensity calculations can help to reduce total loss and the number of casualties after an earthquake. Modern intensity assessment procedures handle a variety of information sources, which can be divided into two main categories. The first type of data is that derived from physical sensors, such as seismographs and accelerometers, while the second type consists of data obtained from social sensors, such as witness observations of the consequences of the earthquake itself. Estimation approaches using additional data sources or that combine sources from both data types tend to increase intensity uncertainty due to human factors and inadequate procedures for temporal and spatial estimation, resulting in precision errors in both time and space. Here we present a processing approach for the real-time analysis of streams of data from both source types. The physical sensor data is acquired from the U.S. Geological Survey (USGS) seismic network in California and the social sensor data is based on Twitter user observations. First, empirical relationships between tweet rate and observed Modified Mercalli Intensity (MMI) are developed using data from the M6.0 South Napa, CAF earthquake that occurred on August 24, 2014. Second, the streams of both data types are analyzed together in simulated real-time to produce one intensity map. The second implementation is based on IBM InfoSphere Streams, a cloud platform for real-time analytics of big data. To handle large processing workloads for data from various sources, it is deployed and run on a cloud-based cluster of virtual machines. We compare the quality and evolution of intensity maps from different data sources over 10-min time intervals immediately following the earthquake. Results from the joint analysis shows that it provides more complete coverage, with better accuracy and higher

  16. Real-Time Joint Streaming Data Processing from Social and Physical Sensors

    Science.gov (United States)

    Kropivnitskaya, Y. Y.; Qin, J.; Tiampo, K. F.; Bauer, M.

    2014-12-01

    The results of the technological breakthroughs in computing that have taken place over the last few decades makes it possible to achieve emergency management objectives that focus on saving human lives and decreasing economic effects. In particular, the integration of a wide variety of information sources, including observations from spatially-referenced physical sensors and new social media sources, enables better real-time seismic hazard analysis through distributed computing networks. The main goal of this work is to utilize innovative computational algorithms for better real-time seismic risk analysis by integrating different data sources and processing tools into streaming and cloud computing applications. The Geological Survey of Canada operates the Canadian National Seismograph Network (CNSN) with over 100 high-gain instruments and 60 low-gain or strong motion seismographs. The processing of the continuous data streams from each station of the CNSN provides the opportunity to detect possible earthquakes in near real-time. The information from physical sources is combined to calculate a location and magnitude for an earthquake. The automatically calculated results are not always sufficiently precise and prompt that can significantly reduce the response time to a felt or damaging earthquake. Social sensors, here represented as Twitter users, can provide information earlier to the general public and more rapidly to the emergency planning and disaster relief agencies. We introduce joint streaming data processing from social and physical sensors in real-time based on the idea that social media observations serve as proxies for physical sensors. By using the streams of data in the form of Twitter messages, each of which has an associated time and location, we can extract information related to a target event and perform enhanced analysis by combining it with physical sensor data. Results of this work suggest that the use of data from social media, in conjunction

  17. Effects of land use and sample location on nitrate-stream flow hysteresis descriptors during storm events

    Science.gov (United States)

    Feinson, Lawrence S.; Gibs, Jacob; Imbrigiotta, Thomas E.; Garrett, Jessica D.

    2016-01-01

    The U.S. Geological Survey's New Jersey and Iowa Water Science Centers deployed ultraviolet-visible spectrophotometric sensors at water-quality monitoring sites on the Passaic and Pompton Rivers at Two Bridges, New Jersey, on Toms River at Toms River, New Jersey, and on the North Raccoon River near Jefferson, Iowa to continuously measure in-stream nitrate plus nitrite as nitrogen (NO3 + NO2) concentrations in conjunction with continuous stream flow measurements. Statistical analysis of NO3 + NO2 vs. stream discharge during storm events found statistically significant links between land use types and sampling site with the normalized area and rotational direction of NO3 + NO2-stream discharge (N-Q) hysteresis patterns. Statistically significant relations were also found between the normalized area of a hysteresis pattern and several flow parameters as well as the normalized area adjusted for rotational direction and minimum NO3 + NO2 concentrations. The mean normalized hysteresis area for forested land use was smaller than that of urban and agricultural land uses. The hysteresis rotational direction of the agricultural land use was opposite of that of the urban and undeveloped land uses. An r2 of 0.81 for the relation between the minimum normalized NO3 + NO2 concentration during a storm vs. the normalized NO3 + NO2 concentration at peak flow suggested that dilution was the dominant process controlling NO3 + NO2 concentrations over the course of most storm events.

  18. Stick-slip Cycles and Tidal Modulation of Ice Stream Flow

    Science.gov (United States)

    Lipovsky, B.; Dunham, E. M.

    2016-12-01

    The reactivation of a single dormant Antarctic ice stream would double the continent's mass imbalance. Despite importance of understanding the likelihood of such an event, direct observation of the basal processes that lead to the activation and stagnation of streaming ice are minimal. As the only ice stream undergoing stagnation, the Whillans Ice Plain (WIP) occupies a central role in our understanding of these subglacial processes. Complicating matters is the observation, from GPS records, that the WIP experiences most of its motion during episodes of rapid sliding. These sliding events are tidally modulated and separated by 12 hour periods of quiescence. We conduct numerical simulations of ice stream stick-slip cycles. Our simulations include rate- and state-dependent frictional sliding, tidal forcing, inertia, upstream loading in a cross-stream, thickness-averaged formulation. Our principal finding is that ice stream motion may respond to ocean tidal forcing with one of two end member behaviors. In one limit, tidally modulated slip events have rupture velocities that approach the shear wave speed and slip events have a duration that scales with the ice stream width divided by the shear wave speed. In the other limit, tidal modulation results in ice stream sliding velocities with lower amplitude variation but at much longer timescales, i.e. semi-diurnal and longer. This latter behavior more closely mimics the behavior of several active ice streams (Bindschadler, Rutford). We find that WIP slip events exist between these two end member behaviors: rupture velocities are far below the inertial limit yet sliding occurs only episodically. The continuum of sliding behaviors is governed by a critical ice stream width over which slip event nucleate. When the critical width is much longer than the ice stream width, slip events are unable to nucleate. The critical width depends on the subglacial effective pressure, ice thickness, and frictional and elastic constitutive

  19. Reducing Door-to-Needle Times using Toyota’s Lean Manufacturing Principles and Value Stream Analysis

    Science.gov (United States)

    Ford, Andria L.; Williams, Jennifer A.; Spencer, Mary; McCammon, Craig; Khoury, Naim; Sampson, Tomoko; Panagos, Peter; Lee, Jin-Moo

    2012-01-01

    Background Earlier tPA treatment for acute ischemic stroke increases efficacy, prompting national efforts to reduce door-to-needle times (DNTs). We utilized lean process improvement methodology to develop a streamlined IV tPA protocol. Methods In early 2011, a multi-disciplinary team analyzed the steps required to treat acute ischemic stroke patients with IV tPA, utilizing value stream analysis (VSA). We directly compared the tPA-treated patients in the “pre-VSA” epoch to the “post-VSA” epoch with regard to baseline characteristics, protocol metrics, and clinical outcomes. Results The VSA revealed several tPA protocol inefficiencies: routing of patients to room, then to CT, then back to room; serial processing of work flow; and delays in waiting for lab results. On 3/1/2011, a new protocol incorporated changes to minimize delays: routing patients directly to head CT prior to patient room, utilizing parallel process work-flow, and implementing point-of-care labs. In the pre-and post-VSA epochs, 132 and 87 patients were treated with IV tPA, respectively. Compared to pre-VSA, DNTs and percent of patients treated ≤60 minutes from hospital arrival were improved in the post-VSA epoch: 60 min vs. 39 min (pLean process improvement methodology can expedite time-dependent stroke care, without compromising safety. PMID:23138440

  20. Influence of the old mining loads on the contamination of streams, flows in the Water-work Reservoir “Ružín I” in 2004 year by the selected elements

    Directory of Open Access Journals (Sweden)

    Tomislav Špaldon

    2005-11-01

    Full Text Available This article presents results of the research concentrated on the content of selected elements, mostly heavy metals, in samples of stream waters and stream deposits from selected profiles of streams in the drainage basins of the Hnilec and Hornád river, which flow in the water-work Reservoir “Ružín I”. The sampling was carried out from the winter to the summer months, 2004. The major part of the drainage basins of these two rivers is located in the territory of the central Spiš, which is well-known from the historic times until these days by its intensive mining, mineral processing and metallurgical activities. The wastes generated by such activities are sources of metals, which penetrate into the surface waters and consequently into the stream deposits. From the point of view of the transfer and the transformation of these metal elements, their monitoring deserves a continuous attention

  1. Relationship between coronal holes and high speed streams at L1: arrival times, durations, and intensities

    Science.gov (United States)

    Luo, B.; Bu, X.; Liu, S.; Gong, J.

    2017-12-01

    Coronal holes are sources of high-speed steams (HSS) of solar wind. When coronal holes appear at mid/low latitudes on the Sun, consequential HSSs may impact Earth and cause recurrent geospace environment disturbances, such as geomagnetic storms, relativistic electron enhancements at the geosynchronous orbit, and thermosphere density enhancements. Thus, it is of interests for space weather forecasters to predict when (arrival times), how long (time durations), and how severe (intensities) HSSs may impact Earth when they notice coronal holes on the sun and are anticipating their geoeffectiveness. In this study, relationship between coronal holes and high speed streams will be statistically investigated. Several coronal hole parameters, including passage times of solar central meridian, coronal hole longitudinal widths, intensities reflected by mean brightness, are derived using Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images for years 2011 to 2016. These parameters will be correlated with in-situ solar wind measurements measured at the L1 point by the ACE spacecraft, which can give some results that are useful for space weather forecaster in predicting the arrival times, durations, and intensities of coronal hole high-speed streams in about 3 days advance.

  2. Assessing the impacts of climate change and tillage practices on stream flow, crop and sediment yields from the Mississippi River Basin

    Science.gov (United States)

    P.B. Parajuli; P. Jayakody; G.F. Sassenrath; Y. Ouyang

    2016-01-01

    This study evaluated climate change impacts on stream flow, crop and sediment yields from three differ-ent tillage systems (conventional, reduced 1–close to conservation, and reduced 2–close to no-till), in theBig Sunflower River Watershed (BSRW) in Mississippi. The Soil and Water Assessment Tool (SWAT) modelwas applied to the BSRW using observed stream flow and crop...

  3. Minimizing total weighted completion time in a proportionate flow shop

    NARCIS (Netherlands)

    Shakhlevich, N.V.; Hoogeveen, J.A.; Pinedo, M.L.

    1998-01-01

    We study the special case of the m machine flow shop problem in which the processing time of each operation of job j is equal to pj; this variant of the flow shop problem is known as the proportionate flow shop problem. We show that for any number of machines and for any regular performance

  4. Residence Time Distributions in a Cold, Confined Swirl Flow

    DEFF Research Database (Denmark)

    Lans, Robert Pieter Van Der; Glarborg, Peter; Dam-Johansen, Kim

    1997-01-01

    Residence time distributions (RTD) in a confined, cold swirling flow have been measured with a fast-response probe and helium as a tracer. The test-rig represented a scaled down version of a burner. The effect of variation of flow velocities and swirl angle on the flow pattern in the near...

  5. Flow-sensitive type recovery in linear-log time

    DEFF Research Database (Denmark)

    Adams, Michael D.; Keep, Andrew W.; Midtgaard, Jan

    2011-01-01

    The flexibility of dynamically typed languages such as JavaScript, Python, Ruby, and Scheme comes at the cost of run-time type checks. Some of these checks can be eliminated via control-flow analysis. However, traditional control-flow analysis (CFA) is not ideal for this task as it ignores flow...

  6. Improving AVSWAT Stream Flow Simulation by Incorporating Groundwater Recharge Prediction in the Upstream Lesti Watershed, East Java, Indonesia

    Directory of Open Access Journals (Sweden)

    Christina Rahayuningtyas

    2014-01-01

    Full Text Available The upstream Lesti watershed is one of the major watersheds of East Java in Indonesia, covering about 38093 hectares. Although there are enough water resources to meet current demands in the basin, many challenges including high spatial and temporal variability in precipitation from year to year exist. It is essential to understand how the climatic condition affects Lesti River stream flow in each sub basin. This study investigated the applicability of using the Soil and Water Assessment Tool (SWAT with the incorporation of groundwater recharge prediction in stream flow simulation in the upstream Lesti watershed. Four observation wells in the upstream Lesti watershed were used to evaluate the seasonal and annual variations in the water level and estimate the groundwater recharge in the deep aquifer. The results show that annual water level rise was within the 2800 - 5700 mm range in 2007, 3900 - 4700 mm in 2008, 3200 - 5100 mm in 2009, and 2800 - 4600 mm in 2010. Based on the specific yield and the measured water level rise, the area-weighted groundwater predictions at the watershed outlet are 736, 820.9, 786.7, 306.4 mm in 2007, 2008, 2009, and 2010, respectively. The consistency test reveals that the R-square statistical value is greater than 0.7, and the DV (% ranged from 32 - 55.3% in 2007 - 2010. Overall, the SWAT model performs better in the wet season flow simulation than the dry season. It is suggested that the SWAT model needs to be improved for stream flow simulation in tropical regions.

  7. Machine-learning-based Brokers for Real-time Classification of the LSST Alert Stream

    Science.gov (United States)

    Narayan, Gautham; Zaidi, Tayeb; Soraisam, Monika D.; Wang, Zhe; Lochner, Michelle; Matheson, Thomas; Saha, Abhijit; Yang, Shuo; Zhao, Zhenge; Kececioglu, John; Scheidegger, Carlos; Snodgrass, Richard T.; Axelrod, Tim; Jenness, Tim; Maier, Robert S.; Ridgway, Stephen T.; Seaman, Robert L.; Evans, Eric Michael; Singh, Navdeep; Taylor, Clark; Toeniskoetter, Jackson; Welch, Eric; Zhu, Songzhe; The ANTARES Collaboration

    2018-05-01

    The unprecedented volume and rate of transient events that will be discovered by the Large Synoptic Survey Telescope (LSST) demand that the astronomical community update its follow-up paradigm. Alert-brokers—automated software system to sift through, characterize, annotate, and prioritize events for follow-up—will be critical tools for managing alert streams in the LSST era. The Arizona-NOAO Temporal Analysis and Response to Events System (ANTARES) is one such broker. In this work, we develop a machine learning pipeline to characterize and classify variable and transient sources only using the available multiband optical photometry. We describe three illustrative stages of the pipeline, serving the three goals of early, intermediate, and retrospective classification of alerts. The first takes the form of variable versus transient categorization, the second a multiclass typing of the combined variable and transient data set, and the third a purity-driven subtyping of a transient class. Although several similar algorithms have proven themselves in simulations, we validate their performance on real observations for the first time. We quantitatively evaluate our pipeline on sparse, unevenly sampled, heteroskedastic data from various existing observational campaigns, and demonstrate very competitive classification performance. We describe our progress toward adapting the pipeline developed in this work into a real-time broker working on live alert streams from time-domain surveys.

  8. Machine Learning-based Transient Brokers for Real-time Classification of the LSST Alert Stream

    Science.gov (United States)

    Narayan, Gautham; Zaidi, Tayeb; Soraisam, Monika; ANTARES Collaboration

    2018-01-01

    The number of transient events discovered by wide-field time-domain surveys already far outstrips the combined followup resources of the astronomical community. This number will only increase as we progress towards the commissioning of the Large Synoptic Survey Telescope (LSST), breaking the community's current followup paradigm. Transient brokers - software to sift through, characterize, annotate and prioritize events for followup - will be a critical tool for managing alert streams in the LSST era. Developing the algorithms that underlie the brokers, and obtaining simulated LSST-like datasets prior to LSST commissioning, to train and test these algorithms are formidable, though not insurmountable challenges. The Arizona-NOAO Temporal Analysis and Response to Events System (ANTARES) is a joint project of the National Optical Astronomy Observatory and the Department of Computer Science at the University of Arizona. We have been developing completely automated methods to characterize and classify variable and transient events from their multiband optical photometry. We describe the hierarchical ensemble machine learning algorithm we are developing, and test its performance on sparse, unevenly sampled, heteroskedastic data from various existing observational campaigns, as well as our progress towards incorporating these into a real-time event broker working on live alert streams from time-domain surveys.

  9. Boundary-layer development and transition due to free-stream exothermic reactions in shock-induced flows

    Science.gov (United States)

    Hall, J. L.

    1974-01-01

    A study of the effect of free-stream thermal-energy release from shock-induced exothermic reactions on boundary-layer development and transition is presented. The flow model is that of a boundary layer developing behind a moving shock wave in two-dimensional unsteady flow over a shock-tube wall. Matched sets of combustible hydrogen-oxygen-nitrogen mixtures and inert hydrogen-nitrogen mixtures were used to obtain transition data over a range of transition Reynolds numbers from 1,100,000 to 21,300,000. The heat-energy is shown to significantly stabilize the boundary layer without changing its development character. A method for application of this data to flat-plate steady flows is included.

  10. Internet Teleoperation of a Robot with Streaming Buffer System under Varying Time Delays

    Science.gov (United States)

    Park, Jahng-Hyon; Shin, Wanjae

    It is known that existence of irregular transmission time delay is a major bottleneck for application of advanced robot control schemes to internet telerobotic systems. In the internet teleoperation system, the irregular transmission time delay causes a critical problem, which includes instability and inaccuracy. This paper suggests a practical internet teleoperation system with streaming buffer system, which consists of a buffer, a buffer manager, and a control timer. The proposed system converts the irregular transmission time delay to a constant. So, the system effectively transmits the control input to a remote site to operate a robot stably and accurately. This feature enables short control input intervals. That means the entire system has a large control bandwidth. The validity of the proposed method is demonstrated by experiments of teleoperation from USC (University of Southern California in U. S.A.) to HYU (Hanyang Univ. in Korea) through the Internet. The proposed method is also demonstrated by experiments of teleoperation through the wireless internet.

  11. Sarcastic sentiment detection in tweets streamed in real time: a big data approach

    Directory of Open Access Journals (Sweden)

    S.K. Bharti

    2016-08-01

    Full Text Available Sarcasm is a type of sentiment where people express their negative feelings using positive or intensified positive words in the text. While speaking, people often use heavy tonal stress and certain gestural clues like rolling of the eyes, hand movement, etc. to reveal sarcastic. In the textual data, these tonal and gestural clues are missing, making sarcasm detection very difficult for an average human. Due to these challenges, researchers show interest in sarcasm detection of social media text, especially in tweets. Rapid growth of tweets in volume and its analysis pose major challenges. In this paper, we proposed a Hadoop based framework that captures real time tweets and processes it with a set of algorithms which identifies sarcastic sentiment effectively. We observe that the elapse time for analyzing and processing under Hadoop based framework significantly outperforms the conventional methods and is more suited for real time streaming tweets.

  12. The Time-Frequency Signatures of Advanced Seismic Signals Generated by Debris Flows

    Science.gov (United States)

    Chu, C. R.; Huang, C. J.; Lin, C. R.; Wang, C. C.; Kuo, B. Y.; Yin, H. Y.

    2014-12-01

    The seismic monitoring is expected to reveal the process of debris flow from the initial area to alluvial fan, because other field monitoring techniques, such as the video camera and the ultrasonic sensor, are limited by detection range. For this reason, seismic approaches have been used as the detection system of debris flows over the past few decades. The analysis of the signatures of the seismic signals in time and frequency domain can be used to identify the different phases of debris flow. This study dedicates to investigate the different stages of seismic signals due to debris flow, including the advanced signal, the main front, and the decaying tail. Moreover, the characteristics of the advanced signals forward to the approach of main front were discussed for the warning purpose. This study presents a permanent system, composed by two seismometers, deployed along the bank of Ai-Yu-Zi Creek in Nantou County, which is one of the active streams with debris flow in Taiwan. The three axes seismometer with frequency response of 7 sec - 200 Hz was developed by the Institute of Earth Sciences (IES), Academia Sinica for the purpose to detect debris flow. The original idea of replacing the geophone system with the seismometer technique was for catching the advanced signals propagating from the upper reach of the stream before debris flow arrival because of the high sensitivity. Besides, the low frequency seismic waves could be also early detected because of the low attenuation. However, for avoiding other unnecessary ambient vibrations, the sensitivity of seismometer should be lower than the general seismometer for detecting teleseism. Three debris flows with different mean velocities were detected in 2013 and 2014. The typical triangular shape was obviously demonstrated in time series data and the spectrograms of the seismic signals from three events. The frequency analysis showed that enormous debris flow bearing huge boulders would induce low frequency seismic

  13. Assessment of the ecological impacts of macroroughness elements in stream flows

    Science.gov (United States)

    Niayifar, Amin; Oldroyd, Holly J.; Perona, Paolo

    2017-04-01

    The environmental suitability of flow release rules is often assessed for different fish species by modeling (e.g., CASiMir and PHABSIM) Weighted Usable Area (WUA) curves. However, these models are not able to resolve the hydrodynamic at small scales, e.g. that induced by the presence of macroroughness (e.g., single stones), which yet determine relatively large wakes that may contribute significantly in terms of habitat suitability. The presence of stones generates sheltered zones (i.e., the wake), which are typically temporary stationary points for many fish species. By resting in these low velocity regions, fishes minimize energy expenditure, and can quickly move to nearby fast water to feed (Hayes and Jowett, 1994). Following the analytical model proposed by Negretti et al., (2006), we developed an analytical solution for the wake area behind the macroroughness elements. The total wake area in the river reach being monitored is a function of the streamflow, Q, and it is an actual Usable Area for fishes that can be used to correct the one computed by classic software such as PHABSIM or CASIMIR at each flow rate. By quantifying these wake areas we can therefore assess how the physical properties and number of such zones change in response to the changing hydrologic regime. In order to validate the concept, we selected a 400 meter reach from the Aare river in the center of Switzerland. The statistical distribution of macroroughness elements is obtained by taking orthorectified aerial photographs by drone surveys during low flow conditions. Then, the distribution of the wakes is obtained analytically as a derived distribution. This methodology allows to save computational costs and the time for detailed field surveys.

  14. Mahanaxar: quality of service guarantees in high-bandwidth, real-time streaming data storage

    Energy Technology Data Exchange (ETDEWEB)

    Bigelow, David [Los Alamos National Laboratory; Bent, John [Los Alamos National Laboratory; Chen, Hsing-Bung [Los Alamos National Laboratory; Brandt, Scott [UCSC

    2010-04-05

    Large radio telescopes, cyber-security systems monitoring real-time network traffic, and others have specialized data storage needs: guaranteed capture of an ultra-high-bandwidth data stream, retention of the data long enough to determine what is 'interesting,' retention of interesting data indefinitely, and concurrent read/write access to determine what data is interesting, without interrupting the ongoing capture of incoming data. Mahanaxar addresses this problem. Mahanaxar guarantees streaming real-time data capture at (nearly) the full rate of the raw device, allows concurrent read and write access to the device on a best-effort basis without interrupting the data capture, and retains data as long as possible given the available storage. It has built in mechanisms for reliability and indexing, can scale to meet arbitrary bandwidth requirements, and handles both small and large data elements equally well. Results from our prototype implementation shows that Mahanaxar provides both better guarantees and better performance than traditional file systems.

  15. Intelligent Stale-Frame Discards for Real-Time Video Streaming over Wireless Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Sheu Tsang-Ling

    2009-01-01

    Full Text Available Abstract This paper presents intelligent early packet discards (I-EPD for real-time video streaming over a multihop wireless ad hoc network. In a multihop wireless ad hoc network, the quality of transferring real-time video streams could be seriously degraded, since every intermediate node (IN functionally like relay device does not possess large buffer and sufficient bandwidth. Even worse, a selected relay node could leave or power off unexpectedly, which breaks the route to destination. Thus, a stale video frame is useless even if it can reach destination after network traffic becomes smooth or failed route is reconfigured. In the proposed I-EPD, an IN can intelligently determine whether a buffered video packet should be early discarded. For the purpose of validation, we implement the I-EPD on Linux-based embedded systems. Via the comparisons of performance metrics (packet/frame discards ratios, PSNR, etc., we demonstrate that video quality over a wireless ad hoc network can be substantially improved and unnecessary bandwidth wastage is greatly reduced.

  16. Threshold responses of Amazonian stream fishes to timing and extent of deforestation.

    Science.gov (United States)

    Brejão, Gabriel L; Hoeinghaus, David J; Pérez-Mayorga, María Angélica; Ferraz, Silvio F B; Casatti, Lilian

    2017-12-06

    Deforestation is a primary driver of biodiversity change through habitat loss and fragmentation. Stream biodiversity may not respond to deforestation in a simple linear relationship. Rather, threshold responses to extent and timing of deforestation may occur. Identification of critical deforestation thresholds is needed for effective conservation and management. We tested for threshold responses of fish species and functional groups to degree of watershed and riparian zone deforestation and time since impact in 75 streams in the western Brazilian Amazon. We used remote sensing to assess deforestation from 1984 to 2011. Fish assemblages were sampled with seines and dip nets in a standardized manner. Fish species (n = 84) were classified into 20 functional groups based on ecomorphological traits associated with habitat use, feeding, and locomotion. Threshold responses were quantified using threshold indicator taxa analysis. Negative threshold responses to deforestation were common and consistently occurred at very low levels of deforestation (70% deforestation and >10 years after impact. Findings were similar at the community level for both taxonomic and functional analyses. Because most negative threshold responses occurred at low levels of deforestation and soon after impact, even minimal change is expected to negatively affect biodiversity. Delayed positive threshold responses to extreme deforestation by a few species do not offset the loss of sensitive taxa and likely contribute to biotic homogenization. © 2017 Society for Conservation Biology.

  17. Use of NTRIP for Optimizing the Decoding Algorithm for Real-Time Data Streams

    Directory of Open Access Journals (Sweden)

    Zhanke He

    2014-10-01

    Full Text Available As a network transmission protocol, Networked Transport of RTCM via Internet Protocol (NTRIP is widely used in GPS and Global Orbiting Navigational Satellite System (GLONASS Augmentation systems, such as Continuous Operational Reference System (CORS, Wide Area Augmentation System (WAAS and Satellite Based Augmentation Systems (SBAS. With the deployment of BeiDou Navigation Satellite system(BDS to serve the Asia-Pacific region, there are increasing needs for ground monitoring of the BeiDou Navigation Satellite system and the development of the high-precision real-time BeiDou products. This paper aims to optimize the decoding algorithm of NTRIP Client data streams and the user authentication strategies of the NTRIP Caster based on NTRIP. The proposed method greatly enhances the handling efficiency and significantly reduces the data transmission delay compared with the Federal Agency for Cartography and Geodesy (BKG NTRIP. Meanwhile, a transcoding method is proposed to facilitate the data transformation from the BINary EXchange (BINEX format to the RTCM format. The transformation scheme thus solves the problem of handing real-time data streams from Trimble receivers in the BeiDou Navigation Satellite System indigenously developed by China.

  18. Use of NTRIP for optimizing the decoding algorithm for real-time data streams.

    Science.gov (United States)

    He, Zhanke; Tang, Wenda; Yang, Xuhai; Wang, Liming; Liu, Jihua

    2014-10-10

    As a network transmission protocol, Networked Transport of RTCM via Internet Protocol (NTRIP) is widely used in GPS and Global Orbiting Navigational Satellite System (GLONASS) Augmentation systems, such as Continuous Operational Reference System (CORS), Wide Area Augmentation System (WAAS) and Satellite Based Augmentation Systems (SBAS). With the deployment of BeiDou Navigation Satellite system(BDS) to serve the Asia-Pacific region, there are increasing needs for ground monitoring of the BeiDou Navigation Satellite system and the development of the high-precision real-time BeiDou products. This paper aims to optimize the decoding algorithm of NTRIP Client data streams and the user authentication strategies of the NTRIP Caster based on NTRIP. The proposed method greatly enhances the handling efficiency and significantly reduces the data transmission delay compared with the Federal Agency for Cartography and Geodesy (BKG) NTRIP. Meanwhile, a transcoding method is proposed to facilitate the data transformation from the BINary EXchange (BINEX) format to the RTCM format. The transformation scheme thus solves the problem of handing real-time data streams from Trimble receivers in the BeiDou Navigation Satellite System indigenously developed by China.

  19. Paper-based enzymatic microfluidic fuel cell: From a two-stream flow device to a single-stream lateral flow strip

    Science.gov (United States)

    González-Guerrero, Maria José; del Campo, F. Javier; Esquivel, Juan Pablo; Giroud, Fabien; Minteer, Shelley D.; Sabaté, Neus

    2016-09-01

    This work presents a first approach towards the development of a cost-effective enzymatic paper-based glucose/O2 microfluidic fuel cell in which fluid transport is based on capillary action. A first fuel cell configuration consists of a Y-shaped paper device with the fuel and the oxidant flowing in parallel over carbon paper electrodes modified with bioelectrocatalytic enzymes. The anode consists of a ferrocenium-based polyethyleneimine polymer linked to glucose oxidase (GOx/Fc-C6-LPEI), while the cathode contains a mixture of laccase, anthracene-modified multiwall carbon nanotubes, and tetrabutylammonium bromide-modified Nafion (MWCNTs/laccase/TBAB-Nafion). Subsequently, the Y-shaped configuration is improved to use a single solution containing both, the anolyte and the catholyte. Thus, the electrolytes pHs of the fuel and the oxidant solutions are adapted to an intermediate pH of 5.5. Finally, the fuel cell is run with this single solution obtaining a maximum open circuit of 0.55 ± 0.04 V and a maximum current and power density of 225 ± 17 μA cm-2 and 24 ± 5 μW cm-2, respectively. Hence, a power source closer to a commercial application (similar to conventional lateral flow test strips) is developed and successfully operated. This system can be used to supply the energy required to power microelectronics demanding low power consumption.

  20. Subsurface lateral flow from hillslope and its contribution to nitrate loading in streams through an agricultural catchment during subtropical rainstorm events

    Directory of Open Access Journals (Sweden)

    B. Zhang

    2011-10-01

    Full Text Available Subsurface lateral flow from agricultural hillslopes is often overlooked compared with overland flow and tile drain flow, partly due to the difficulties in monitoring and quantifying. The objectives of this study were to examine how subsurface lateral flow generated through soil pedons from cropped hillslopes and to quantify its contribution to nitrate loading in the streams through an agricultural catchment in the subtropical region of China. Profiles of soil water potential along hillslopes and stream hydro-chemographs in a trenched stream below a cropped hillslope and at the catchment outlet were simultaneously recorded during two rainstorm events. The dynamics of soil water potential showed positive matrix soil water potential over impermeable soil layer at 0.6 to 1.50 m depths during and after the storms, indicating soil water saturation and drainage processes along the hillslopes irrespective of land uses. The hydro-chemographs in the streams, one trenched below a cropped hillslope and one at the catchment outlet, showed that the concentrations of particulate nitrogen and phosphorus corresponded well to stream flow during the storm, while the nitrate concentration increased on the recession limbs of the hydrographs after the end of the storm. All the synchronous data revealed that nitrate was delivered from the cropped hillslope through subsurface lateral flow to the streams during and after the end of the rainstorms. A chemical mixing model based on electricity conductivity (EC and H+ concentration was successfully established, particularly for the trenched stream. The results showed that the subsurface lateral flow accounted for 29% to 45% of total stream flow in the trenched stream, responsible for 86% of total NO3-N loss (or 26% of total N loss, and for 5.7% to 7.3% of total stream flow at the catchment outlet, responsible for about 69% of total NO3-N loss (or 28% of total N

  1. Flow level performance approximations for elastic traffic integrated with prioritized stream traffic

    NARCIS (Netherlands)

    Malhotra, R.; Berg, J.L. van den

    2007-01-01

    Almost all traffic in todays networks can be classified as being either stream or elastic. The support of these two traffic types is possible either with a Differentiated (DiffServ) or an Integrated Services (IntServ) architecture. However, both DiffServ and IntServ rely on efficient scheduling

  2. Distance, flow and PCR inhibition: eDNA dynamics in two headwater streams

    Science.gov (United States)

    Stephen F. Jane; Taylor M. Wilcox; Kevin S. McKelvey; Michael K. Young; Michael K. Schwartz; Winsor H. Lowe; Benjamin H. Letcher; Andrew R. Whiteley

    2014-01-01

    Environmental DNA (eDNA) detection has emerged as a powerful tool for monitoring aquatic organisms, but much remains unknown about the dynamics of aquatic eDNA over a range of environmental conditions. DNA concentrations in streams and rivers will depend not only on the equilibrium between DNA entering the water and DNA leaving the system through degradation, but also...

  3. An explicit multi-time-stepping algorithm for aerodynamic flows

    NARCIS (Netherlands)

    Niemann-Tuitman, B.E.; Veldman, A.E.P.

    1997-01-01

    An explicit multi-time-stepping algorithm with applications to aerodynamic flows is presented. In the algorithm, in different parts of the computational domain different time steps are taken, and the flow is synchronized at the so-called synchronization levels. The algorithm is validated for

  4. Single walled carbon nanotubes on MHD unsteady flow over a porous wedge with thermal radiation with variable stream conditions

    Directory of Open Access Journals (Sweden)

    R. Kandasamy

    2016-03-01

    Full Text Available The objective of the present work was to investigate theoretically the effect of single walled carbon nanotubes (SWCNTs in the presence of water and seawater with variable stream condition due to solar radiation energy. The conclusion is drawn that the flow motion and the temperature field for SWCNTs in the presence of base fluid are significantly influenced by magnetic field, convective radiation and thermal stratification. Thermal boundary layer of SWCNTs-water is compared to that of Cu-water, absorbs the incident solar radiation and transits it to the working fluid by convection.

  5. Intensity Maps Production Using Real-Time Joint Streaming Data Processing From Social and Physical Sensors

    Science.gov (United States)

    Kropivnitskaya, Y. Y.; Tiampo, K. F.; Qin, J.; Bauer, M.

    2015-12-01

    Intensity is one of the most useful measures of earthquake hazard, as it quantifies the strength of shaking produced at a given distance from the epicenter. Today, there are several data sources that could be used to determine intensity level which can be divided into two main categories. The first category is represented by social data sources, in which the intensity values are collected by interviewing people who experienced the earthquake-induced shaking. In this case, specially developed questionnaires can be used in addition to personal observations published on social networks such as Twitter. These observations are assigned to the appropriate intensity level by correlating specific details and descriptions to the Modified Mercalli Scale. The second category of data sources is represented by observations from different physical sensors installed with the specific purpose of obtaining an instrumentally-derived intensity level. These are usually based on a regression of recorded peak acceleration and/or velocity amplitudes. This approach relates the recorded ground motions to the expected felt and damage distribution through empirical relationships. The goal of this work is to implement and evaluate streaming data processing separately and jointly from both social and physical sensors in order to produce near real-time intensity maps and compare and analyze their quality and evolution through 10-minute time intervals immediately following an earthquake. Results are shown for the case study of the M6.0 2014 South Napa, CA earthquake that occurred on August 24, 2014. The using of innovative streaming and pipelining computing paradigms through IBM InfoSphere Streams platform made it possible to read input data in real-time for low-latency computing of combined intensity level and production of combined intensity maps in near-real time. The results compare three types of intensity maps created based on physical, social and combined data sources. Here we correlate

  6. Experimental analysis of flow of ductile cast iron in stream lined gating systems

    DEFF Research Database (Denmark)

    Skov-Hansen, Søren Peter; Tiedje, Niels Skat

    2008-01-01

    Streamlined gating systems have been developed for production of high integrity ductile cast iron parts. Flow of ductile cast iron in streamlined gating systems was studied in glass fronted sand moulds where flow in the gating system and casting was recorded by a digital video camera. These results...... show how the quality of pouring, design of ingates, design of bends and flow over cores influence melt flow and act to determine the quality of the castings....

  7. Exploring inter-frame correlation analysis and wavelet-domain modeling for real-time caption detection in streaming video

    Science.gov (United States)

    Li, Jia; Tian, Yonghong; Gao, Wen

    2008-01-01

    In recent years, the amount of streaming video has grown rapidly on the Web. Often, retrieving these streaming videos offers the challenge of indexing and analyzing the media in real time because the streams must be treated as effectively infinite in length, thus precluding offline processing. Generally speaking, captions are important semantic clues for video indexing and retrieval. However, existing caption detection methods often have difficulties to make real-time detection for streaming video, and few of them concern on the differentiation of captions from scene texts and scrolling texts. In general, these texts have different roles in streaming video retrieval. To overcome these difficulties, this paper proposes a novel approach which explores the inter-frame correlation analysis and wavelet-domain modeling for real-time caption detection in streaming video. In our approach, the inter-frame correlation information is used to distinguish caption texts from scene texts and scrolling texts. Moreover, wavelet-domain Generalized Gaussian Models (GGMs) are utilized to automatically remove non-text regions from each frame and only keep caption regions for further processing. Experiment results show that our approach is able to offer real-time caption detection with high recall and low false alarm rate, and also can effectively discern caption texts from the other texts even in low resolutions.

  8. Real-time alpha monitoring of a radioactive liquid waste stream at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.D.; Whitley, C.R.; Rawool-Sullivan, M. [Los Alamos National Lab., NM (United States)

    1995-12-31

    This poster display concerns the development, installation, and testing of a real-time radioactive liquid waste monitor at Los Alamos National Laboratory (LANL). The detector system was designed for the LANL Radioactive Liquid Waste Treatment Facility so that influent to the plant could be monitored in real time. By knowing the activity of the influent, plant operators can better monitor treatment, better segregate waste (potentially), and monitor the regulatory compliance of users of the LANL Radioactive Liquid Waste Collection System. The detector system uses long-range alpha detection technology, which is a nonintrusive method of characterization that determines alpha activity on the liquid surface by measuring the ionization of ambient air. Extensive testing has been performed to ensure long-term use with a minimal amount of maintenance. The final design was a simple cost-effective alpha monitor that could be modified for monitoring influent waste streams at various points in the LANL Radioactive Liquid Waste Collection System.

  9. Influences of high-flow events on a stream channel altered by construction of a highway bridge: A case study

    Science.gov (United States)

    Hedrick, Lara B.; Welsh, Stuart A.; Anderson, James T.

    2009-01-01

    Impacts of highway construction on streams in the central Appalachians are a growing concern as new roads are created to promote tourism and economic development in the area. Alterations to the streambed of a first-order stream, Sauerkraut Run, Hardy County, WV, during construction of a highway overpass included placement and removal of a temporary culvert, straightening and regrading of a section of stream channel, and armourment of a bank with a reinforced gravel berm. We surveyed longitudinal profiles and cross sections in a reference reach and the altered reach of Sauerkraut Run from 2003 through 2007 to measure physical changes in the streambed. During the four-year period, three high-flow events changed the streambed downstream of construction including channel widening and aggradation and then degradation of the streambed. Upstream of construction, at a reinforced gravel berm, bank erosion was documented. The reference section remained relatively unchanged. Knowledge gained by documenting channel changes in response to natural and anthropogenic variables can be useful for managers and engineers involved in highway construction projects.

  10. Null stream analysis of Pulsar Timing Array data: localisation of resolvable gravitational wave sources

    Science.gov (United States)

    Goldstein, Janna; Veitch, John; Sesana, Alberto; Vecchio, Alberto

    2018-04-01

    Super-massive black hole binaries are expected to produce a gravitational wave (GW) signal in the nano-Hertz frequency band which may be detected by pulsar timing arrays (PTAs) in the coming years. The signal is composed of both stochastic and individually resolvable components. Here we develop a generic Bayesian method for the analysis of resolvable sources based on the construction of `null-streams' which cancel the part of the signal held in common for each pulsar (the Earth-term). For an array of N pulsars there are N - 2 independent null-streams that cancel the GW signal from a particular sky location. This method is applied to the localisation of quasi-circular binaries undergoing adiabatic inspiral. We carry out a systematic investigation of the scaling of the localisation accuracy with signal strength and number of pulsars in the PTA. Additionally, we find that source sky localisation with the International PTA data release one is vastly superior than what is achieved by its constituent regional PTAs.

  11. Time resolved flow-field measurements of a turbulent mixing layer over a rectangular cavity

    Science.gov (United States)

    Bian, Shiyao; Driscoll, James F.; Elbing, Brian R.; Ceccio, Steven L.

    2011-07-01

    High Reynolds number, low Mach number, turbulent shear flow past a rectangular, shallow cavity has been experimentally investigated with the use of dual-camera cinematographic particle image velocimetry (CPIV). The CPIV had a 3 kHz sampling rate, which was sufficient to monitor the time evolution of large-scale vortices as they formed, evolved downstream and impinged on the downstream cavity wall. The time-averaged flow properties (velocity and vorticity fields, streamwise velocity profiles and momentum and vorticity thickness) were in agreement with previous cavity flow studies under similar operating conditions. The time-resolved results show that the separated shear layer quickly rolled-up and formed eddies immediately downstream of the separation point. The vortices convect downstream at approximately half the free-stream speed. Vorticity strength intermittency as the structures approach the downstream edge suggests an increase in the three-dimensionality of the flow. Time-resolved correlations reveal that the in-plane coherence of the vortices decays within 2-3 structure diameters, and quasi-periodic flow features are present with a vortex passage frequency of ~1 kHz. The power spectra of the vertical velocity fluctuations within the shear layer revealed a peak at a non-dimensional frequency corresponding to that predicted using linear, inviscid instability theory.

  12. A hierarchical model of daily stream temperature using air-water temperature synchronization, autocorrelation, and time lags

    Directory of Open Access Journals (Sweden)

    Benjamin H. Letcher

    2016-02-01

    Full Text Available Water temperature is a primary driver of stream ecosystems and commonly forms the basis of stream classifications. Robust models of stream temperature are critical as the climate changes, but estimating daily stream temperature poses several important challenges. We developed a statistical model that accounts for many challenges that can make stream temperature estimation difficult. Our model identifies the yearly period when air and water temperature are synchronized, accommodates hysteresis, incorporates time lags, deals with missing data and autocorrelation and can include external drivers. In a small stream network, the model performed well (RMSE = 0.59°C, identified a clear warming trend (0.63 °C decade−1 and a widening of the synchronized period (29 d decade−1. We also carefully evaluated how missing data influenced predictions. Missing data within a year had a small effect on performance (∼0.05% average drop in RMSE with 10% fewer days with data. Missing all data for a year decreased performance (∼0.6 °C jump in RMSE, but this decrease was moderated when data were available from other streams in the network.

  13. The Effect of Beaver Activity on the Ammonium Uptake and Water Residence Time Characteristics of a Third-Order Stream Reach

    Science.gov (United States)

    Briggs, M.; Gooseff, M. N.; Wollheim, W. M.; Peterson, B. J.; Morkeski, K.

    2009-12-01

    Increasing beaver populations within low gradient basins in the northeastern United States are fundamentally changing the way water and dissolved nutrients are exported through these stream networks to the coast. Beaver dams can increase water residence time and contact with organic material, promote anoxic conditions and enhance both surface and hyporheic transient storage; all of these may have an impact on biogeochemical reactivity and nutrient retention. To quantitatively assess some of these effects we co-injected NaCl and NH4+ into the same 3rd-order stream reach in Massachusetts, USA under pre- and post-dam conditions. These experiments were done at similar discharge rates to isolate the impacts of a large natural beaver dam (7 m X 1.3 m) on the low-gradient (0.002) system where variable discharge also imparts a strong control on residence time. During the post-dam experiment there was an estimated 2300 m3 of water impounded behind the structure, which influenced more than 300 m of the 650 m stream reach. Our results showed that median transport time through the reach increased by 160% after dam construction. Additionally the tracer tailing time normalized to the corresponding median transport time increased from 1.08 to 1.51, indicating a pronounced tailing of the tracer signal in the post-dam condition. Data collected within the beaver pond just upstream of the dam indicated poor mixing and the presence of preferential flow paths through the generally stagnant zone. The uptake length (Sw) for NH4+ was 1250 m under the pre-dam condition, and may have changed for the post-dam reach in part because of the observed changes in residence time. As beaver population growth continues within these basins the consequences may be a smoothing of the outlet hydrograph and increased nutrient and organic matter removal and storage along the stream network.

  14. Unsteady flow around a two-dimensional section of a vertical axis turbine for tidal stream energy conversion

    Directory of Open Access Journals (Sweden)

    Hyun Ju Jung

    2009-12-01

    Full Text Available The two-dimensional unsteady flow around a vertical axis turbine for tidal stream energy conversion was investigated using a computational fluid dynamics tool solving the Reynolds-Averaged Navier-Stokes equations. The geometry of the turbine blade section was NACA653-018 airfoil. The computational analysis was done at several different angles of attack and the results were compared with the corresponding experimental data for validation and calibration. Simulations were then carried out for the two-dimensional cross section of a vertical axis turbine. The simulation results demonstrated the usefulness of the method for the typical unsteady flows around vertical axis turbines. The optimum turbine efficiency was achieved for carefully selected combinations of the number of blades and tip speed ratios.

  15. Effects of Watershed Land Use and Geomorphology on Stream Low Flows During Severe Drought Conditions in the Southern Blue Ridge Mountains, Georgia and North Carolina, United States

    Science.gov (United States)

    Land use and physiographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the influence of land use and watershed geomorphic characteristics on low-flow variability in the southern Blue Ridge Mo...

  16. The conversion of grasslands to forests in Southern South America: Shifting evapotranspiration, stream flow and groundwater dynamics

    Science.gov (United States)

    Jobbagy, E. G.; Nosetto, M. D.; Pineiro, G.; Farley, K. A.; Palmer, S. M.; Jackson, R. B.

    2005-12-01

    Vegetation changes, particularly those involving transitions between tree- and grass-dominated systems, often modify evaporation as a result of plant-mediated shifts in moisture access and demand. The establishment of tree plantations (fast growing eucalypts and pines) on native grasslands is emerging as a major land-use change, particularly in the Southern Hemisphere, where cheap land and labor, public subsidies, and prospective C sequestration rewards provide converging incentives. What are the hydrological consequences of grassland afforestation? How are crucial ecosystem services such as fresh water supply and hydrological regulation being affected? We explore these questions focusing on a) evapotranspiration, b) stream flow, and c) groundwater recharge-discharge patterns across a network of paired stands and small watershed occupied by native grassland and tree plantation in Argentina and Uruguay. Radiometric information obtained from Landsat satellite images was used to estimate daily evapotranspiration in >100 tree plantations and grasslands stands in the humid plains of the Uruguay River (mean annual precipitation, MAP= 1350 mm). In spite of their lower albedo, tree plantations were 0.5 C° cooler than grasslands. Energy balance calculations suggested 80% higher evapotranspiration in afforested plots with relative differences becoming larger during dry periods. Seasonal stream flow measurements in twelve paired watershed (50-500 Ha) in the hills of Comechingones (MAP= 800 mm) and Minas (MAP= 1200 mm) showed declining water yields following afforestation. Preliminary data in Cordoba showed four-fold reductions of base flow in the dry season and two-fold reductions of peak flow after storms. A network of twenty paired grassland-plantation stands covering a broad range of sediment textures in the Pampas (MAP= 1000 mm, typical groundwater depth= 1-5 m) showed increased groundwater salinity in afforested stands (plantation:grassland salinity ratio = 1.2, 10, and

  17. Robust and Optimal Control of Magnetic Microparticles inside Fluidic Channels with Time-Varying Flow Rates

    Directory of Open Access Journals (Sweden)

    Islam S.M. Khalil

    2016-06-01

    Full Text Available Targeted therapy using magnetic microparticles and nanoparticles has the potential to mitigate the negative side-effects associated with conventional medical treatment. Major technological challenges still need to be addressed in order to translate these particles into in vivo applications. For example, magnetic particles need to be navigated controllably in vessels against flowing streams of body fluid. This paper describes the motion control of paramagnetic microparticles in the flowing streams of fluidic channels with time-varying flow rates (maximum flow is 35 ml.hr−1. This control is designed using a magnetic-based proportional-derivative (PD control system to compensate for the time-varying flow inside the channels (with width and depth of 2 mm and 1.5 mm, respectively. First, we achieve point-to-point motion control against and along flow rates of 4 ml.hr−1, 6 ml.hr−1, 17 ml.hr−1, and 35 ml.hr−1. The average speeds of single microparticle (with average diameter of 100 μm against flow rates of 6 ml.hr−1 and 30 ml.hr−1 are calculated to be 45 μm.s−1 and 15 μm.s−1, respectively. Second, we implement PD control with disturbance estimation and compensation. This control decreases the steady-state error by 50%, 70%, 73%, and 78% at flow rates of 4 ml.hr−1, 6 ml.hr−1, 17 ml.hr−1, and 35 ml.hr−1, respectively. Finally, we consider the problem of finding the optimal path (minimal kinetic energy between two points using calculus of variation, against the mentioned flow rates. Not only do we find that an optimal path between two collinear points with the direction of maximum flow (middle of the fluidic channel decreases the rise time of the microparticles, but we also decrease the input current that is supplied to the electromagnetic coils by minimizing the kinetic energy of the microparticles, compared to a PD control with disturbance compensation.

  18. Carcinogenic ptaquiloside in stream water at base flow and during storm events

    DEFF Research Database (Denmark)

    Strobel, Bjarne W.; Clauson-Kaas, Frederik; Hansen, Hans Chr. Bruun

    2017-01-01

    identified, of which the compound ptaquiloside (PTA) is the most abundant. Ptaquiloside has been shown to be highly water soluble, leachable from bracken fronds and litter, and present in the soil below bracken stands. During storm events throughfall from the bracken canopy was collected as well. Stream...... water samples were taken as grab samples, while throughfall accumulated in glass jars set out below the canopy. Field blanks and fortified lab controls were included to ensure reliability of the analysis. Ptaquiloside concentrations were determined using LC-MS/MS after a clean-up using solid phase...... extraction. Results showed that PTA levels in the stream were highly dependent on precipitation, and was rising considerably during rain events, peaking at 2.28 μg/L, before quickly (conservation...

  19. Speed scaling for weighted flow time

    NARCIS (Netherlands)

    Bansal, N.; Pruhs, K.R.; Stein, C.

    2007-01-01

    In addition to the traditional goal of efficiently managing time and space, many computers now need to efficiently manage power usage. For example, Intel's SpeedStep and AMD's PowerNOW technologies allow the Windows XP operating system to dynamically change the speed of the processor to prolong

  20. A millennium-length reconstruction of Bear River stream flow, Utah

    Science.gov (United States)

    R. J. DeRose; M. F. Bekker; S.-Y. Wang; B. M. Buckley; R. K. Kjelgren; T. Bardsley; T. M. Rittenour; E. B. Allen

    2015-01-01

    The Bear River contributes more water to the eastern Great Basin than any other river system. It is also the most significant source of water for the burgeoning Wasatch Front metropolitan area in northern Utah. Despite its importance for water resources for the region’s agricultural, urban, and wildlife needs, our understanding of the variability of Bear River’s stream...

  1. Stirring inertia in time-dependent low Reynolds number flows

    Science.gov (United States)

    Yecko, Philip; Luchtenburg, Dirk Martin (Mark); Forgoston, Eric; Billings, Lora

    2017-11-01

    Diagnosis of a kinematic flow and its transport using Lagrangian coherent structures (LCS) based on finite-time Lyapunov exponents (FTLE) neglects dynamical effects, such as pressure, as well as dynamically important constraints, such as potential vorticity conservation. Chaotic advection, on the other hand, often neglects inertial effects, which are prominent in LCS. We present results for very low Reynolds number laboratory flows, including a Stokes double gyre, vertically sheared strain and a four roll mill. Images of tracer (dye) and FTLE fields computed from particle image velocimetry (PIV) reveal complementary sets of flow structures, giving a more complete picture of transport in these flows. We confirm by computing FTLE of an exact time-dependent Stokes flow solution and present implications of these findings for inertial object transport in flows. Support of NSF DMS-1418956 is gratefully acknoweldged.

  2. A GIS-based groundwater travel time model to evaluate stream nitrate concentration reductions from land use change

    Science.gov (United States)

    Schilling, K.E.; Wolter, C.F.

    2007-01-01

    Excessive nitrate-nitrogen (nitrate) loss from agricultural watersheds is an environmental concern. A common conservation practice to improve stream water quality is to retire vulnerable row croplands to grass. In this paper, a groundwater travel time model based on a geographic information system (GIS) analysis of readily available soil and topographic variables was used to evaluate the time needed to observe stream nitrate concentration reductions from conversion of row crop land to native prairie in Walnut Creek watershed, Iowa. Average linear groundwater velocity in 5-m cells was estimated by overlaying GIS layers of soil permeability, land slope (surrogates for hydraulic conductivity and gradient, respectively) and porosity. Cells were summed backwards from the stream network to watershed divide to develop a travel time distribution map. Results suggested that groundwater from half of the land planted in prairie has reached the stream network during the 10 years of ongoing water quality monitoring. The mean travel time for the watershed was estimated to be 10.1 years, consistent with results from a simple analytical model. The proportion of land in the watershed and subbasins with prairie groundwater reaching the stream (10-22%) was similar to the measured reduction of stream nitrate (11-36%). Results provide encouragement that additional nitrate reductions in Walnut Creek are probable in the future as reduced nitrate groundwater from distal locations discharges to the stream network in the coming years. The high spatial resolution of the model (5-m cells) and its simplicity may make it potentially applicable for land managers interested in communicating lag time issues to the public, particularly related to nitrate concentration reductions over time. ?? 2007 Springer-Verlag.

  3. Whole-stream metabolism of a perennial spring-fed aufeis field in Alaska, with coincident surface and subsurface flow

    Science.gov (United States)

    Hendrickson, P. J.; Gooseff, M. N.; Huryn, A. D.

    2017-12-01

    Aufeis (icings or naleds) are seasonal arctic and sub-arctic features that accumulate through repeated overflow and freeze events of river or spring discharge. Aufeis fields, defined as the substrate on which aufeis form and the overlaying ice, have been studied to mitigate impacts on engineering structures; however, ecological characteristics and functions of aufeis fields are poorly understood. The perennial springs that supply warm water to aufeis fields create unique fluvial habitats, and are thought to act as winter and summer oases for biota. To investigate ecosystem function, we measured whole-stream metabolism at the Kuparuk River Aufeis (North Slope, AK), a large ( 5 km2) field composed of cobble substrate and predominately subsurface flow dynamics. The single-station open channel diel oxygen method was utilized at several dissolved oxygen (DO) stations located within and downstream of the aufeis field. DO loggers were installed in August 2016, and data downloaded summer 2017. Daily ecosystem respiration (ER), gross primary production (GPP) and reaeration rates were modeled using BASE, a package freely available in the open-source software R. Preliminary results support net heterotrophy during a two-week period of DO measurements in the fall season when minimum ice extent is observed. GPP, ER, and net metabolism are greater at the upstream reach near the spring source (P/R = 0.53), and decrease as flow moves downstream. As flow exits the aufeis field, surface and subsurface flow are incorporated into the metabolism model, and indicate the stream system becomes dependent on autochthonous production (P/R = 0.91). Current work is directed towards spring and summer discharge and metabolic parameter estimation, which is associated with maximum ice extent and rapid melting of the aufeis feature.

  4. On-stream chemical element monitor

    International Nuclear Information System (INIS)

    Averitt, O.R.; Dorsch, R.R.

    1979-01-01

    An apparatus and method for on-stream chemical element monitoring are described wherein a multiplicity of sample streams are flowed continuously through individual analytical cells and fluorescence analyses are performed on the sample streams in sequence, together with a method of controlling the time duration of each analysis as a function of the concomitant radiation exposure of a preselected perforate reference material interposed in the sample-radiation source path

  5. DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

    International Nuclear Information System (INIS)

    Unknown

    1999-01-01

    The US Department of Energy (DOE) has expressed a need for an on-line, real-time instrument for assaying alpha-emitting radionuclides (uranium and the transuranics) in effluent waters leaving DOE sites to ensure compliance with regulatory limits. Due to the short range of alpha particles in water (approximately40 Im), it is necessary now to intermittently collect samples of water and send them to a central laboratory for analysis. A lengthy and costly procedure is used to separate and measure the radionuclides from each sample. Large variations in radionuclide concentrations in the water may go undetected due to the sporadic sampling. Even when detected, the reading may not be representative of the actual stream concentration. To address these issues, the Advanced Technologies Group of Thermo Power Corporation (a Thermo Electron company) is developing a real-time, field-deployable alpha monitor based on a solid-state silicon wafer semiconductor (US Patent 5,652,013 and pending, assigned to the US Department of Energy). The Thermo Water Alpha Monitor will serve to monitor effluent water streams (Subsurface Contaminants Focus Area) and will be suitable for process control of remediation as well as decontamination and decommissioning (D and D) operations, such as monitoring scrubber or rinse water radioactivity levels (Mixed Waste, Plutonium, and D and D Focus Area). It would be applicable for assaying other liquids, such as oil, or solids after proper preconditioning. Rapid isotopic alpha air monitoring is also possible using this technology. This report details the program's accomplishments to date. Most significantly, the Alpha Monitoring Instrument was successfully field demonstrated on water 100X below the Environmental Protection Agency's proposed safe drinking water limit--down to under 1 pCi/1. During the Field Test, the Alpha Monitoring Instrument successfully analyzed isotopic uranium levels on a total of five different surface water, process water, and

  6. DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

    International Nuclear Information System (INIS)

    1996-01-01

    The Department of Energy (DOE) has expressed a need for an on-line, real-time instrument for assaying alpha-emitting radionuclides (uranium and the transuranics) in effluent waters leaving DOE sites to ensure compliance with regulatory limits. Due to the short range of alpha particles in water (approximately40 Tm), it is necessary now to intermittently collect samples of water and send them to a central laboratory for analysis. A lengthy and costly procedure is used to separate and measure the radionuclides from each sample. Large variations in radionuclide concentrations in the water may go undetected due to the sporadic sampling. Even when detected, the reading may not be representative of the actual stream concentration. To address these issues, Tecogen, a division of Thermo Power Corporation, a Thermo Electron company, is developing a real-time, field-deployable, alpha monitor based on a solid-state silicon wafer semiconductor (patent pending, to be assigned to the Department of Energy). The Thermo Alpha Monitor (TAM) will serve to monitor effluent water streams (Subsurface Contaminants Focus Area) and will be suitable for process control of remediation as well as decontamination and decommissioning operations, such as monitoring scrubber or rinse water radioactivity levels (Mixed Waste Focus Area and D and D Focus Area). It would be applicable for assaying other liquids, such as oil, or solids after proper preconditioning. Rapid isotopic alpha air monitoring is also possible using this technology. This instrument for direct counting of alpha-emitters in aqueous streams is presently being developed by Thermo Power under a development program funded by the DOE Environmental Management program (DOE-EM), administered by the Morgantown Energy Technology Center (METC). Under this contract, Thermo Power has demonstrated a solid-state, silicon-based semiconductor instrument, which uses a proprietary film-based collection system to quantitatively extract the

  7. Determining the times and distances of particle transit in a mountain stream using fallout radionuclides

    Science.gov (United States)

    Bonniwell, Everett C.; Matisoff, Gerald; Whiting, Peter J.

    1999-02-01

    Targeting of erosion and pollution control programs is much more effective if the time for fine particles to be transported through a watershed, the travel distance, the proportions of old and new sediment in suspension, and the rate of erosion of the landscape can be estimated. In this paper we present a novel technique for tracing suspended sediment in a mountain stream using fallout radionuclides sorbed to sediment. Atmospherically-delivered 7Be, 210Pb, and 137Cs accumulate in the snowpack, are released with its melting and sorb to fine particulates, a portion of which are carried downslope into stream channels. The half-life of cosmogenic 7Be is short (53.4 days), thus, sediment residing on the stream bed should contain little of the radionuclide. The different signatures of newly delivered sediment from the landscape with its 7Be tag and older untagged sediment from the channel is the basis for the tracing. The total flux of such radionuclides, compared to the inventory in the soil, permits estimates of the rates of erosion of the landscape. Fine suspended particulates in the Gold Fork River, ID, are transported downstream through the drainage in one or more steps having lengths of tens of kilometers. Length of the step decreases from about 60 km near the peak of the hydrograph to about 12 km near baseflow. The percent of sediment in suspension that is `new' (i.e., recently delivered from the landscape) ranges from 96 to 12%. The remaining sediment is resuspended older channel sediment. Residence times for particulates range from 1.6 days, early in the hydrograph at the upper site, to 103 days late in the hydrograph at the lowest elevation location. Rates of erosion of fine sediment calculated from the flux of radionuclides average 0.0023 cm/year. The long distance transport of fine particles suggests that delivery through the Gold Fork drainage to the basin outlet is fairly rapid once particles reach the channel and perhaps is also rapid in similar and

  8. Salmon carcass movements in forest streams

    Science.gov (United States)

    Burke Strobel; Daniel R. Shivley; Brett B. Roper

    2009-01-01

    The movements of salmon carcasses over time were studied in two forest streams in the context of a large-scale salmon carcass supplementation program. The objectives were to assess both the level of treatment after stream flows had displaced carcasses and to evaluate whether the magnitude of carcass movements outside of a given reach could be predicted. The movements...

  9. Persistent Tracers of Historic Ice Flow in Glacial Stratigraphy near Kamb Ice Stream, West Antarctica

    OpenAIRE

    Holschuh, Nicholas; Christianson, Knut; Conway, Howard; Jacobel, Robert W.; Welch, Brian C.

    2018-01-01

    Variations in properties controlling ice flow (e.g., topography, accumulation rate, basal friction) are recorded by structures in glacial stratigraphy. When anomalies that disturb the stratigraphy are fixed in space, the structures they produce advect away from the source, and can be used to trace flow pathways and reconstruct ice-flow patterns of the past. Here we provide an example of one of these persistent tracers: a prominent unconformity in the glacial layering that originates at Mt. Re...

  10. A transit-time flow meter for measuring milliliter per minute liquid flow

    DEFF Research Database (Denmark)

    Yang, Canqian; Kymmel, Mogens; Søeberg, Henrik

    1988-01-01

    A transit-time flow meter, using periodic temperature fluctuations as tracers, has been developed for measuring liquid flow as small as 0.1 ml/min in microchannels. By injecting square waves of heat into the liquid flow upstream with a tiny resistance wire heater, periodic temperature fluctuation....... This flow meter will be used to measure and control the small liquid flow in microchannels in flow injection analysis. Review of Scientific Instruments is copyrighted by The American Institute of Physics....... are generated downstream. The fundamental frequency phase shift of the temperature signal with respect to the square wave is found to be a linear function of the reciprocal mean velocity of the fluid. The transit-time principle enables the flow meter to have high accuracy, better than 0.2%, and good linearity...

  11. Time varying determinants of bond flows to emerging markets

    Directory of Open Access Journals (Sweden)

    Yasemin Erduman

    2016-06-01

    Full Text Available This paper investigates the time varying nature of the determinants of bond flows with a focus on the global financial crisis period. We estimate a time varying regression model using Bayesian estimation methods, where the posterior distribution is approximated by Gibbs sampling algorithm. Our findings suggest that the interest rate differential is the most significant pull factor of portfolio bond flows, along with the inflation rate, while the growth rate does not play a significant role. Among the push factors, global liquidity is the most important driver of bond flows. It matters the most, when unconventional monetary easing policies were first announced; and its importance as a determinant of portfolio bond flows decreases over time, starting with the Eurozone crisis, and diminishes with the tapering talk. Global risk appetite and the risk perception towards the emerging countries also have relatively small and stable significant effects on bond flows.

  12. Time-Efficiency of Sorting Chironomidae Surface-Floating Pupal Exuviae Samples from Urban Trout Streams in Northeast Minnesota, USA

    Directory of Open Access Journals (Sweden)

    Alyssa M Anderson

    2012-10-01

    Full Text Available Collections of Chironomidae surface-floating pupal exuviae (SFPE provide an effective means of assessing water quality in streams. Although not widely used in the United States, the technique is not new and has been shown to be more cost-efficient than traditional dip-net sampling techniques in organically enriched stream in an urban landscape. The intent of this research was to document the efficiency of sorting SFPE samples relative to dip-net samples in trout streams with catchments varying in amount of urbanization and differences in impervious surface. Samples of both SFPE and dip-nets were collected from 17 sample sites located on 12 trout streams in Duluth, MN, USA. We quantified time needed to sort subsamples of 100 macroinvertebrates from dip-net samples, and less than or greater than 100 chironomid exuviae from SFPE samples. For larger samples of SFPE, the time required to subsample up to 300 exuviae was also recorded. The average time to sort subsamples of 100 specimens was 22.5 minutes for SFPE samples, compared to 32.7 minutes for 100 macroinvertebrates in dip-net samples. Average time to sort up to 300 exuviae was 37.7 minutes. These results indicate that sorting SFPE samples is more time-efficient than traditional dip-net techniques in trout streams with varying catchment characteristics.doi: 10.5324/fn.v31i0.1380.Published online: 17 October 2012.

  13. Hyporheic Exchange Flows and Biogeochemical Patterns near a Meandering Stream: East Fork of the Jemez River, Valles Caldera National Preserve, New Mexico

    Science.gov (United States)

    Christensen, H.; Wooten, J. P.; Swanson, E.; Senison, J. J.; Myers, K. D.; Befus, K. M.; Warden, J.; Zamora, P. B.; Gomez, J. D.; Wilson, J. L.; Groffman, A.; Rearick, M. S.; Cardenas, M. B.

    2012-12-01

    A study by the 2012 Hydrogeology Field Methods class of the University of Texas at Austin implemented multiple approaches to evaluate and characterize local hyporheic zone flow and biogeochemical trends in a highly meandering reach of the of the East Fork of the Jemez River, a fourth order stream in northwestern New Mexico. This section of the Jemez River is strongly meandering and exhibits distinct riffle-pool morphology. The high stream sinuosity creates inter-meander hyporheic flow that is also largely influenced by local groundwater gradients. In this study, dozens of piezometers were used to map the water table and flow vectors were then calculated. Surface water and ground water samples were collected and preserved for later geochemical analysis by ICPMS and HPLC, and unstable parameters and alkalinity were measured on-site. Additionally, information was collected from thermal monitoring of the streambed, stream gauging, and from a series of electrical resistivity surveys forming a network across the site. Hyporheic flow paths are suggested by alternating gaining and losing sections of the stream as determined by stream gauging at multiple locations along the reach. Water table maps and calculated fluxes across the sediment-water interface also indicate hyporheic flow paths. We find variability in the distribution of biogeochemical constituents (oxidation-reduction potential, nitrate, ammonium, and phosphate) along interpreted flow paths which is partly consistent with hyporheic exchange. The variability and heterogeneity of reducing and oxidizing conditions is interpreted to be a result of groundwater-surface water interaction. Two-dimensional mapping of biogeochemical parameters show redox transitions along interpreted flow paths. Further analysis of various measured unstable chemical parameters results in observable trends strongly delineated along these preferential flow paths that are consistent with the direction of groundwater flow and the assumed

  14. Improving Wait Times to Care for Individuals with Multimorbidities and Complex Conditions Using Value Stream Mapping

    Directory of Open Access Journals (Sweden)

    Tara Sampalli

    2015-07-01

    Full Text Available Background Recognizing the significant impact of wait times for care for individuals with complex chronic conditions, we applied a LEAN methodology, namely – an adaptation of Value Stream Mapping (VSM to meet the needs of people with multiple chronic conditions and to improve wait times without additional resources or funding. Methods Over an 18-month time period, staff applied a patient-centric approach that included LEAN methodology of VSM to improve wait times to care. Our framework of evaluation was grounded in the needs and perspectives of patients and individuals waiting to receive care. Patient centric views were obtained through surveys such as Patient Assessment of Chronic Illness Care (PACIC and process engineering based questions. In addition, LEAN methodology, VSM was added to identify non-value added processes contributing to wait times. Results The care team successfully reduced wait times to 2 months in 2014 with no wait times for care anticipated in 2015. Increased patient engagement and satisfaction are also outcomes of this innovative initiative. In addition, successful transformations and implementation have resulted in resource efficiencies without increase in costs. Patients have shown significant improvements in functional health following Integrated Chronic Care Service (ICCS intervention. The methodology will be applied to other chronic disease management areas in Capital Health and the province. Conclusion Wait times to care in the management of multimoribidities and other complex conditions can add a significant burden not only on the affected individuals but also on the healthcare system. In this study, a novel and modified LEAN methodology has been applied to embed the voice of the patient in care delivery processes and to reduce wait times to care in the management of complex chronic conditions.

  15. Evaluating Use of Environmental Flows to Aerate Streams by Modelling the Counterfactual Case

    Science.gov (United States)

    Stewardson, Michael J.; Skinner, Dominic

    2018-03-01

    This paper evaluates an experimental environmental flow manipulation by modeling the counterfactual case that no environmental flow was applied. This is an alternate approach to evaluating the effect of an environmental flow intervention when a before-after or control-impact comparison is not possible. In this case, the flow manipulation is a minimum flow designed to prevent hypoxia in a weir on the low-gradient Broken Creek in south-eastern Australia. At low flows, low reaeration rates and high respiration rates associated with elevated organic matter loading in the weir pool can lead to a decline in dissolved oxygen concentrations with adverse consequences both for water chemistry and aquatic biota. Using a one dimensional oxygen balance model fitted to field measurements, this paper demonstrates that increased flow leads to increases in reaeration rates, presumably because of enhanced turbulence and hence mixing in the surface layers. By comparing the observed dissolved oxygen levels with the modeled counterfactual case, we show that the environmental flow was effective in preventing hypoxia.

  16. New methods for modeling stream temperature using high resolution LiDAR, solar radiation analysis and flow accumulated values to predict stream temperature

    Science.gov (United States)

    In-stream temperature directly effects a variety of biotic organisms, communities and processes. Changes in stream temperature can render formally suitable habitat unsuitable for aquatic organisms, particularly native cold water species that are not able to adjust. In order to...

  17. Water quality, streamflow conditions, and annual flow-duration curves for streams of the San Juan–Chama Project, southern Colorado and northern New Mexico, 1935-2010

    Science.gov (United States)

    Falk, Sarah E.; Anderholm, Scott K.; Hafich, Katya A.

    2013-01-01

    , Horse Lake Creek, and Willow Creek watersheds, which are underlain mostly by Cretaceous-aged marine shale, was compositionally similar and had large concentrations of sulfate relative to the other streams in the study area, though the water from the Navajo River had lower specific-conductance values than did the water from Horse Lake Creek above Heron Reservoir and Willow Creek above Azotea Creek. Generally, surface-water quality varied with streamflow conditions throughout the year. Streamflow in spring and summer is generally a mixture of base flow (the component of streamflow derived from groundwater discharged to the stream channel) diluted with runoff from snowmelt and precipitation events, whereas streamflow in fall and winter is generally solely base flow. Major- and trace-element concentrations in the streams sampled were lower than U.S. Environmental Protection Agency primary and secondary drinking-water standards and New Mexico Environment Department surface-water standards for the streams. In general, years with increased annual discharge, compared to years with decreased annual discharge, had a smaller percentage of discharge in March, a larger percentage of discharge in June, an interval of discharge derived from snowmelt runoff that occurred later in the year, and a larger discharge in June. Additionally, years with increased annual discharge generally had a longer duration of runoff, and the streamflow indicators occurred at dates later in the year than the years with less snowmelt runoff. Additionally, the seasonal distribution of streamflow was more strongly controlled by the change in the amount of annual discharge than by changes in streamflow over time. The variation of streamflow conditions over time at one streamflow-gaging station in the study area, Navajo River at Banded Peak Ranch, was not significantly monotonic over the period of record with a Kendall’s tau of 0.0426 and with a p-value of 0.5938 for 1937 to 2009 (a trend was considered

  18. Impact of climate change on the stream flow of the lower Brahmaputra: trends in high and low flows based on discharge-weighted ensemble modelling

    Directory of Open Access Journals (Sweden)

    A. K. Gain

    2011-05-01

    Full Text Available Climate change is likely to have significant effects on the hydrology. The Ganges-Brahmaputra river basin is one of the most vulnerable areas in the world as it is subject to the combined effects of glacier melt, extreme monsoon rainfall and sea level rise. To what extent climate change will impact river flow in the Brahmaputra basin is yet unclear, as climate model studies show ambiguous results. In this study we investigate the effect of climate change on both low and high flows of the lower Brahmaputra. We apply a novel method of discharge-weighted ensemble modeling using model outputs from a global hydrological models forced with 12 different global climate models (GCMs. Our analysis shows that only a limited number of GCMs are required to reconstruct observed discharge. Based on the GCM outputs and long-term records of observed flow at Bahadurabad station, our method results in a multi-model weighted ensemble of transient stream flow for the period 1961–2100. Using the constructed transients, we subsequently project future trends in low and high river flow. The analysis shows that extreme low flow conditions are likely to occur less frequent in the future. However a very strong increase in peak flows is projected, which may, in combination with projected sea level change, have devastating effects for Bangladesh. The methods presented in this study are more widely applicable, in that existing multi-model streamflow simulations from global hydrological models can be weighted against observed streamflow data to assess at first order the effects of climate change for specific river basins.

  19. Component flow processes at four streams in the Catskill Mountains, New York, analysed using episodic concentration/discharge relationship

    Science.gov (United States)

    Evans, C.; Davies, T.D.; Murdoch, Peter S.

    1999-01-01

    Plots of solute concentration against discharge have been used to relate stream hydrochemical variations to processes of flow generation, using data collected at four streams in the Catskill Mountains, New York, during the Episodic Response Project of the US Environmental Protection Agency. Results suggest that a two-component system of shallow and deep saturated subsurface flow, in which the two components respond simultaneously during hydrologic events, may be applicable to the study basins. Using a large natural sea-salt sodium input as a tracer for precipitation, it is argued that an additional distinction can be made between pre-event and event water travelling along the shallow subsurface flow path. Pre-event water is thought to be displaced by infiltrating event water, which becomes dominant on the falling limb of the hydrograph. Where, as appears to be the case for sulfate, a solute equilibrates rapidly within the soil, the pre-event-event water distinction is unimportant. However, for some solutes there are clear and consistent compositional differences between water from the two sources, evident as a hysteresis loop in concentration-discharge plots. Nitrate and acidity, in particular, appear to be elevated in event water following percolation through the organic horizon. Consequently, the most acidic, high nitrate conditions during an episode generally occur after peak discharge. A simple conceptual model of episode runoff generation is presented on the basis of these results.Plots of solute concentration against discharge have been used to relate stream hydrochemical variations to processes of flow generation, using data collected at four streams in the Catskill Mountains, New York, during the Episodic Response Project of the US Environmental Protection Agency. Results suggest that a two-component system of shallow and deep saturated subsurface flow, in which the two components respond simultaneously during hydrologic events, may be applicable to the

  20. Assessing roadway contributions to stormwater flows, concentrations, and loads with the StreamStats application

    Science.gov (United States)

    Stonewall, Adam; Granato, Gregory E.; Haluska, Tana L.

    2018-01-01

    The Oregon Department of Transportation (ODOT) and other state departments of transportation need quantitative information about the percentages of different land cover categories above any given stream crossing in the state to assess and address roadway contributions to water-quality impairments and resulting total maximum daily loads. The U.S. Geological Survey, in cooperation with ODOT and the FHWA, added roadway and land cover information to the online StreamStats application to facilitate analysis of stormwater runoff contributions from different land covers. Analysis of 25 delineated basins with drainage areas of about 100 mi2 indicates the diversity of land covers in the Willamette Valley, Oregon. On average, agricultural, developed, and undeveloped land covers comprise 15%, 2.3%, and 82% of these basin areas. On average, these basins contained about 10 mi of state highways and 222 mi of non-state roads. The Stochastic Empirical Loading and Dilution Model was used with available water-quality data to simulate long-term yields of total phosphorus from highways, non-highway roadways, and agricultural, developed, and undeveloped areas. These yields were applied to land cover areas obtained from StreamStats for the Willamette River above Wilsonville, Oregon. This analysis indicated that highway yields were larger than yields from other land covers because highway runoff concentrations were higher than other land covers and the highway is fully impervious. However, the total highway area was a fraction of the other land covers. Accordingly, highway runoff mitigation measures can be effective for managing water quality locally, they may have limited effect on achieving basin-wide stormwater reduction goals.

  1. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study.

    Science.gov (United States)

    Pennell, Thomas; Yi, Juneyoung L; Kaufman, Bruce A; Krishnamurthy, Satish

    2016-03-01

    OBJECT Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure CSF flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data. To address these needs, this preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drains (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor's capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor's ability to identify these changes. METHODS A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient's neurological status and their time points were noted. RESULTS The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow. CONCLUSIONS The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml

  2. Sensitivity analysis of time-dependent laminar flows

    International Nuclear Information System (INIS)

    Hristova, H.; Etienne, S.; Pelletier, D.; Borggaard, J.

    2004-01-01

    This paper presents a general sensitivity equation method (SEM) for time dependent incompressible laminar flows. The SEM accounts for complex parameter dependence and is suitable for a wide range of problems. The formulation is verified on a problem with a closed form solution obtained by the method of manufactured solution. Systematic grid convergence studies confirm the theoretical rates of convergence in both space and time. The methodology is then applied to pulsatile flow around a square cylinder. Computations show that the flow starts with symmetrical vortex shedding followed by a transition to the traditional Von Karman street (alternate vortex shedding). Simulations show that the transition phase manifests itself earlier in the sensitivity fields than in the flow field itself. Sensitivities are then demonstrated for fast evaluation of nearby flows and uncertainty analysis. (author)

  3. sedFlow – a tool for simulating fractional bedload transport and longitudinal profile evolution in mountain streams

    Directory of Open Access Journals (Sweden)

    F. U. M. Heimann

    2015-01-01

    floods. The model is intended for temporal scales from the individual event (several hours to few days up to longer-term evolution of stream channels (several years. The envisaged spatial scale covers complete catchments at a spatial discretisation of several tens of metres to a few hundreds of metres. sedFlow can deal with the effects of streambeds that slope uphill in a downstream direction and uses recently proposed and tested approaches for quantifying macro-roughness effects in steep channels. sedFlow offers different options for bedload transport equations, flow-resistance relationships and other elements which can be selected to fit the current application in a particular catchment. Local grain-size distributions are dynamically adjusted according to the transport dynamics of each grain-size fraction. sedFlow features fast calculations and straightforward pre- and postprocessing of simulation data. The high simulation speed allows for simulations of several years, which can be used, e.g., to assess the long-term impact of river engineering works or climate change effects. In combination with the straightforward pre- and postprocessing, the fast calculations facilitate efficient workflows for the simulation of individual flood events, because the modeller gets the immediate results as direct feedback to the selected parameter inputs. The model is provided together with its complete source code free of charge under the terms of the GNU General Public License (GPL (www.wsl.ch/sedFlow. Examples of the application of sedFlow are given in a companion article by Heimann et al. (2015.

  4. Knowledge discovery from data streams

    CERN Document Server

    Gama, Joao

    2010-01-01

    Since the beginning of the Internet age and the increased use of ubiquitous computing devices, the large volume and continuous flow of distributed data have imposed new constraints on the design of learning algorithms. Exploring how to extract knowledge structures from evolving and time-changing data, Knowledge Discovery from Data Streams presents a coherent overview of state-of-the-art research in learning from data streams.The book covers the fundamentals that are imperative to understanding data streams and describes important applications, such as TCP/IP traffic, GPS data, sensor networks,

  5. Collaborative Approaches to Flow Restoration in Intermittent Salmon-Bearing Streams: Salmon Creek, CA, USA

    Directory of Open Access Journals (Sweden)

    Cleo Woelfle-Erskine

    2017-03-01

    Full Text Available In Mediterranean-climate regions of California and southern Oregon, juvenile salmon depend on groundwater aquifers to sustain their tributary habitats through the dry summers. Along California’s North Coast streams, private property regimes on land have created commons tragedies in groundwater and salmon fisheries, both classic examples of commons that are often governed collectively and sustainably by their users. Understanding the linkages between salmon and groundwater is one major focus of salmon recovery and climate change adaptation planning in central California and increasingly throughout the Pacific Northwest. In this paper, I use extended field interviews and participant-observation in field ecology campaigns and regulatory forums to explore how, in one water-scarce, salmon-bearing watershed on California’s central coast, collaborators are synthesizing agency and landowner data on groundwater and salmon management. I focus on three projects undertaken by citizen scientists in collaboration with me and Gold Ridge Resource Conservation District staff: salmonid censuses, mapping of wet and dry stream reaches and well monitoring. I find that collaborative research initiated by local residents and agency personnel has, in some cases, created a new sense of ecological possibility in the region. I also consider some limitations of this collaborations, namely the lack of engagement with indigenous Pomo and Miwok tribal members, with the Confederated Tribes of Graton Rancheria and with farmworkers and other marginalized residents, and suggest strategies for deepening environmental justice commitments in future collaborative work.

  6. DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

    International Nuclear Information System (INIS)

    Unknown

    1999-01-01

    Thermo Power Corporation has proven the technical viability of an on-line, real-time alpha radionuclide instrument for aqueous sample analysis through laboratory and initial field tests of the instrument. The instrument has been shown to be isotonically sensitive to extremely low (ten parts per trillion, or femto Curies per liter) levels of a broad range of radioisotopes. Performance enhancement and other scaling data obtained during the course of this investigation have shown that on-line, real-time operation is possible, with a sub 30-minute response time analyzing 20 ppb (30 pCi/1) natural uranium. Now that these initial field tests in Oak Ridge, Tennessee have been successfully completed, Thermo Power plans to conduct comprehensive field tests of the instrument. The purpose of these endurance tests will be to determine the endurance characteristics of the Thermo Alpha Monitor for Water when it is used by non-Thermo Power personnel in a series of one or more extended field tests. Such endurance testing is the vital next step towards the commercialization of the Alpha Monitor. Subsequently, it will be possible to provide the DOE with an instrument that has the capability of obtaining rapid feedback about the concentrations of alpha-emitting isotope contamination in effluent water streams (Subsurface Contaminants Focus Area). It will also be useful for process control of remediation and D and D operations such as monitoring scrubber/rinse water radioactivity levels (Mixed Waste, Plutonium and D and D Focus Areas)

  7. Reducing door-to-needle times using Toyota's lean manufacturing principles and value stream analysis.

    Science.gov (United States)

    Ford, Andria L; Williams, Jennifer A; Spencer, Mary; McCammon, Craig; Khoury, Naim; Sampson, Tomoko R; Panagos, Peter; Lee, Jin-Moo

    2012-12-01

    Earlier tissue-type plasminogen activator (tPA) treatment for acute ischemic stroke increases efficacy, prompting national efforts to reduce door-to-needle times. We used lean process improvement methodology to develop a streamlined intravenous tPA protocol. In early 2011, a multidisciplinary team analyzed the steps required to treat patients with acute ischemic stroke with intravenous tPA using value stream analysis (VSA). We directly compared the tPA-treated patients in the "pre-VSA" epoch with the "post-VSA" epoch with regard to baseline characteristics, protocol metrics, and clinical outcomes. The VSA revealed several tPA protocol inefficiencies: routing of patients to room, then to CT, then back to the room; serial processing of workflow; and delays in waiting for laboratory results. On March 1, 2011, a new protocol incorporated changes to minimize delays: routing patients directly to head CT before the patient room, using parallel process workflow, and implementing point-of-care laboratories. In the pre and post-VSA epochs, 132 and 87 patients were treated with intravenous tPA, respectively. Compared with pre-VSA, door-to-needle times and percent of patients treated ≤60 minutes from hospital arrival were improved in the post-VSA epoch: 60 minutes versus 39 minutes (PLean process improvement methodology can expedite time-dependent stroke care without compromising safety.

  8. MAC-Layer Active Dropping for Real-Time Video Streaming in 4G Access Networks

    KAUST Repository

    She, James

    2010-12-01

    This paper introduces a MAC-layer active dropping scheme to achieve effective resource utilization, which can satisfy the application-layer delay for real-time video streaming in time division multiple access based 4G broadband wireless access networks. When a video frame is not likely to be reconstructed within the application-layer delay bound at a receiver for the minimum decoding requirement, the MAC-layer protocol data units of such video frame will be proactively dropped before the transmission. An analytical model is developed to evaluate how confident a video frame can be delivered within its application-layer delay bound by jointly considering the effects of time-varying wireless channel, minimum decoding requirement of each video frame, data retransmission, and playback buffer. Extensive simulations with video traces are conducted to prove the effectiveness of the proposed scheme. When compared to conventional cross-layer schemes using prioritized-transmission/retransmission, the proposed scheme is practically implementable for more effective resource utilization, avoiding delay propagation, and achieving better video qualities under certain conditions.

  9. Using stable isotope tracers to assess hydrological flow paths, residence times and landscape influences in a nested mesoscale catchment

    Directory of Open Access Journals (Sweden)

    P. Rodgers

    2005-01-01

    Full Text Available δ18O measurements in precipitation and stream waters were used to investigate hydrological flow paths and residence times at nested spatial scales in the mesoscale (233 km2 River Feugh catchment in the northeast of Scotland over the 2001-2002 hydrological year. Precipitation δ18O exhibited strong seasonal variation, which although significantly damped within the catchment, was reflected in stream water at six sampling sites. This allowed δ18O variations to be used to infer the relative influence of soil-derived storm flows with a seasonally variable isotopic signature, and groundwater of apparently more constant isotopic composition. Periodic regression analysis was then used to examine the sub-catchment difference using an exponential flow model to provide indicative estimates of mean stream water residence times, which varied between approximately 3 and 14 months. This showed that the effects of increasing scale on estimated mean stream water residence time was minimal beyond that of the smallest (ca. 1 km2 headwater catchment scale. Instead, the interaction of catchment soil cover and topography appeared to be the dominant controlling influence. Where sub-catchments had extensive peat coverage, responsive hydrological pathways produced seasonally variable δ18O signatures in runoff with short mean residence times (ca. 3 months. In contrast, areas dominated by steeper slopes, more freely draining soils and larger groundwater storage in shallow valley-bottom aquifers, deeper flow paths allow for more effective mixing and damping of δ18O indicating longer residence times (>12 months. These insights from δ18O measurements extend the hydrological understanding of the Feugh catchment gained from previous geochemical tracer studies, and demonstrate the utility of isotope tracers in investigating the interaction of hydrological processes and catchment characteristics at larger spatial scales.

  10. A new time-space accounting scheme to predict stream water residence time and hydrograph source components at the watershed scale

    Science.gov (United States)

    Takahiro Sayama; Jeffrey J. McDonnell

    2009-01-01

    Hydrograph source components and stream water residence time are fundamental behavioral descriptors of watersheds but, as yet, are poorly represented in most rainfall-runoff models. We present a new time-space accounting scheme (T-SAS) to simulate the pre-event and event water fractions, mean residence time, and spatial source of streamflow at the watershed scale. We...

  11. Pitot pressure measurements in flow fields behind circular-arc nozzles with exhaust jets at subsonic free-stream Mach numbers. [langley 16 foot transonic tunnel

    Science.gov (United States)

    Mason, M. L.; Putnam, L. E.

    1979-01-01

    The flow field behind a circular arc nozzle with exhaust jet was studied at subsonic free stream Mach numbers. A conical probe was used to measure the pitot pressure in the jet and free stream regions. Pressure data were recorded for two nozzle configurations at nozzle pressure ratios of 2.0, 2.9, and 5.0. At each set of test conditions, the probe was traversed from the jet center line into the free stream region at seven data acquisition stations. The survey began at the nozzle exit and extended downstream at intervals. The pitot pressure data may be applied to the evaluation of computational flow field models, as illustrated by a comparison of the flow field data with results of inviscid jet plume theory.

  12. Hydrogeological approach to the regional analysis of low flow in medium and small streams of the hilly and mountainous areas of Serbia

    Directory of Open Access Journals (Sweden)

    Nikić Zoran

    2006-01-01

    Full Text Available During the long rainless spells of the dry season, flows in medium and small streams get reduced to what is generally known as "low flow". For ungauged streams, the controlling "low flows" are determined using the regional analysis method. In the presently described exploration, the method applied was based on the assumption that dry weather discharges in medium and small rivers depended on the hydrogeological conditions. The controlling effect of hydrogeology on the natural low flow in medium and small streams of the hilly and mountainous part of Serbia was analyzed applying the theory of multiple linear regression. The thirty-day minimum mean 80 and 95 per cent exceedance flows were taken for dependent variables, and quantified hydrogeological elements as independent variables. The analysis covered streams that had small or medium size catchment areas. The treated example encompassed sixty-one gauged catchments. The resulting regional relations for the thirty day minimum mean 80 and 95 per cent exceedance flows are presented in this paper. The quality of the established relation was controlled by relevant statistic tests.

  13. Visualization Measurement of Streaming Flows Associated with a Single-Acoustic Levitator

    Science.gov (United States)

    Hasegawa, Koji; Abe, Yutaka; Kaneko, Akiko; Yamamoto, Yuji; Aoki, Kazuyoshi

    2009-08-01

    The purpose of the study is to experimentally investigate flow fields generated by an acoustic levitator. This flow field has been observed using flow visualization, PIV method. In the absent of a drop, the flow field was strongly influenced by sound pressure level (SPL). In light of the interfacial stability of a levitated drop, SPL was set at 161-163 [dB] in our experiments. In the case of any levitated drop at a pressure node of a standing wave, the toroidal vortices were appeared around a drop and clearly observed the flow fields around the drop by PIV measurement. It is found that the toroidal vortices around a levitated drop were strongly affected by the viscosity of a drop. For more detailed research, experiments in the reduced gravity were conducted with aircraft parabolic flights. By comparison with experimental results in the earth and reduced gravity, it is also indicated that the configuration of the external flow field around a drop is most likely to be affected by a position of a drop as well.

  14. Characteristic time series and operation region of the system of two tank reactors (CSTR) with variable division of recirculation stream

    International Nuclear Information System (INIS)

    Merta, Henryk

    2006-01-01

    The paper deals with a system of a cascade of two tank reactors, being characterized by the variable stream of recirculating fluid at each stage. The assumed mathematical model enables one to determine the system's dynamics for the case when there is no time delay and for the opposite case. The time series of the conversion degree and of the dimensionless fluid temperature, characteristic for the system considered as well as the operation regions-the latter-basing on Feingenbaum diagrams with respect to the division ratio of the recirculating stream are presented

  15. Response and recovery of water yield and timing, stream sediment, abiotic parameters, and stream chemistry following logging

    Science.gov (United States)

    Wayne Swank; Jennifer Knoepp; James Vose; Stephanie Laseter; Jackson Webster

    2014-01-01

    Watershed ecosystem analysis provides a scientific approach to quantify and integrate resource responses to management (Hornbeck and Swank 1992) and also to address issues of resource sustainability (Christensen et. al. 1996). Philosophical components of the research approach at Coweeta are 1) the quantity, timing, and quality of streamflow provides an integrated...

  16. Autonomous watersheds: Reducing flooding and stream erosion through real-time control

    Science.gov (United States)

    Kerkez, B.; Wong, B. P.

    2017-12-01

    We introduce an analytical toolchain, based on dynamical system theory and feedback control, to determine how many control points (valves, gates, pumps, etc.) are needed to transform urban watersheds from static to adaptive. Advances and distributed sensing and control stand to fundamentally change how we manage urban watersheds. In lieu of new and costly infrastructure, the real-time control of stormwater systems will reduce flooding, mitigate stream erosion, and improve the treatment of polluted runoff. We discuss the how open source technologies, in the form of wireless sensor nodes and remotely-controllable valves (open-storm.org), have been deployed to build "smart" stormwater systems in the Midwestern US. Unlike "static" infrastructure, which cannot readily adapt to changing inputs and land uses, these distributed control assets allow entire watersheds to be reconfigured on a storm-by-storm basis. Our results show how the control of even just a few valves within urban catchments (1-10km^2) allows for the real-time "shaping" of hydrographs, which reduces downstream erosion and flooding. We also introduce an equivalence framework that can be used by decision-makers to objectively compare investments into "smart" system to more traditional solutions, such as gray and green stormwater infrastructure.

  17. Learning a Continuous-Time Streaming Video QoE Model.

    Science.gov (United States)

    Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C

    2018-05-01

    Over-the-top adaptive video streaming services are frequently impacted by fluctuating network conditions that can lead to rebuffering events (stalling events) and sudden bitrate changes. These events visually impact video consumers' quality of experience (QoE) and can lead to consumer churn. The development of models that can accurately predict viewers' instantaneous subjective QoE under such volatile network conditions could potentially enable the more efficient design of quality-control protocols for media-driven services, such as YouTube, Amazon, Netflix, and so on. However, most existing models only predict a single overall QoE score on a given video and are based on simple global video features, without accounting for relevant aspects of human perception and behavior. We have created a QoE evaluator, called the time-varying QoE Indexer, that accounts for interactions between stalling events, analyzes the spatial and temporal content of a video, predicts the perceptual video quality, models the state of the client-side data buffer, and consequently predicts continuous-time quality scores that agree quite well with human opinion scores. The new QoE predictor also embeds the impact of relevant human cognitive factors, such as memory and recency, and their complex interactions with the video content being viewed. We evaluated the proposed model on three different video databases and attained standout QoE prediction performance.

  18. Uncertainty analysis of power monitoring transit time ultrasonic flow meters

    International Nuclear Information System (INIS)

    Orosz, A.; Miller, D. W.; Christensen, R. N.; Arndt, S.

    2006-01-01

    A general uncertainty analysis is applied to chordal, transit time ultrasonic flow meters that are used in nuclear power plant feedwater loops. This investigation focuses on relationships between the major parameters of the flow measurement. For this study, mass flow rate is divided into three components, profile factor, density, and a form of volumetric flow rate. All system parameters are used to calculate values for these three components. Uncertainty is analyzed using a perturbation method. Sensitivity coefficients for major system parameters are shown, and these coefficients are applicable to a range of ultrasonic flow meters used in similar applications. Also shown is the uncertainty to be expected for density along with its relationship to other system uncertainties. One other conclusion is that pipe diameter sensitivity coefficients may be a function of the calibration technique used. (authors)

  19. Timing of revenue streams from newly recruited faculty: implications for faculty retention.

    Science.gov (United States)

    Joiner, Keith A; Hiteman, Sarah; Wormsley, Steven; St Germain, Patricia

    2007-12-01

    To determine the timing and magnitude of revenues generated by newly recruited faculty, to facilitate configuration of recruitment packages appropriately matched to expected financial returns. The aggregate of all positive cash flows to central college of medicine administration -- from research, clinical care, tuition, philanthropy, and royalties and patents, from all faculty newly recruited to the University of Arizona College of Medicine between 1998 and 2004 -- was quantified using the net present value (npv) methodology, which incorporates the time value of money. Tenure-track faculty and, in particular, those with laboratory research programs, generated the highest positive central cash flows. The npv for positive cash flows (npv[+]) during 6 and 10 years for newly recruited assistant professors with laboratory research programs were $118,600 and $255,400, respectively, and, for professors with laboratory research programs, $172,600 and $298,000, respectively (associate professors were not analyzed because of limited numbers). Faculty whose appointments at the University of Arizona College of Medicine exceeded 15 years in duration were the most productive in central revenue generation, far in excess of their numbers proportionate to the total. The results emphasize the critical importance of faculty retention, because even those newly recruited faculty who are most successful in central revenue generation (tenure track with laboratory research programs) must be retained for periods well in excess of 10 years to recoup the initial central investment required for their recruitment.

  20. Flood and Weather Monitoring Using Real-time Twitter Data Streams

    Science.gov (United States)

    Demir, I.; Sit, M. A.; Sermet, M. Y.

    2016-12-01

    Social media data is a widely used source to making inference within public crisis periods and events in disaster times. Specifically, since Twitter provides large-scale data publicly in real-time, it is one of the most extensive resources with location information. This abstract provides an overview of a real-time Twitter analysis system to support flood preparedness and response using a comprehensive information-centric flood ontology and natural language processing. Within the scope of this project, we deal with acquisition and processing of real-time Twitter data streams. System fetches the tweets with specified keywords and classifies them as related to flooding or heavy weather conditions. The system uses machine learning algorithms to discover patterns using the correlation between tweets and Iowa Flood Information System's (IFIS) extensive resources. The system uses these patterns to forecast the formation and progress of a potential future flood event. While fetching tweets, predefined hashtags are used for filtering and enhancing the relevancy for selected tweets. With this project, tweets can also be used as an alternative data source where other data sources are not sufficient for specific tasks. During the disasters, the photos that people upload alongside their tweets can be collected and placed to appropriate locations on a mapping system. This allows decision making authorities and communities to see the most recent outlook of the disaster interactively. In case of an emergency, concentration of tweets can help the authorities to determine a strategy on how to reach people most efficiently while providing them the supplies they need. Thanks to the extendable nature of the flood ontology and framework, results from this project will be a guide for other natural disasters, and will be shared with the community.

  1. An empirical method for approximating stream baseflow time series using groundwater table fluctuations

    Science.gov (United States)

    Meshgi, Ali; Schmitter, Petra; Babovic, Vladan; Chui, Ting Fong May

    2014-11-01

    Developing reliable methods to estimate stream baseflow has been a subject of interest due to its importance in catchment response and sustainable watershed management. However, to date, in the absence of complex numerical models, baseflow is most commonly estimated using statistically derived empirical approaches that do not directly incorporate physically-meaningful information. On the other hand, Artificial Intelligence (AI) tools such as Genetic Programming (GP) offer unique capabilities to reduce the complexities of hydrological systems without losing relevant physical information. This study presents a simple-to-use empirical equation to estimate baseflow time series using GP so that minimal data is required and physical information is preserved. A groundwater numerical model was first adopted to simulate baseflow for a small semi-urban catchment (0.043 km2) located in Singapore. GP was then used to derive an empirical equation relating baseflow time series to time series of groundwater table fluctuations, which are relatively easily measured and are physically related to baseflow generation. The equation was then generalized for approximating baseflow in other catchments and validated for a larger vegetation-dominated basin located in the US (24 km2). Overall, this study used GP to propose a simple-to-use equation to predict baseflow time series based on only three parameters: minimum daily baseflow of the entire period, area of the catchment and groundwater table fluctuations. It serves as an alternative approach for baseflow estimation in un-gauged systems when only groundwater table and soil information is available, and is thus complementary to other methods that require discharge measurements.

  2. Real-Time Video Stylization Using Object Flows.

    Science.gov (United States)

    Lu, Cewu; Xiao, Yao; Tang, Chi-Keung

    2017-05-05

    We present a real-time video stylization system and demonstrate a variety of painterly styles rendered on real video inputs. The key technical contribution lies on the object flow, which is robust to inaccurate optical flow, unknown object transformation and partial occlusion as well. Since object flows relate regions of the same object across frames, shower-door effect can be effectively reduced where painterly strokes and textures are rendered on video objects. The construction of object flows is performed in real time and automatically after applying metric learning. To reduce temporal flickering, we extend the bilateral filtering into motion bilateral filtering. We propose quantitative metrics to measure the temporal coherence on structures and textures of our stylized videos, and perform extensive experiments to compare our stylized results with baseline systems and prior works specializing in watercolor and abstraction.

  3. Retailer's optimal credit period and cycle time in a supply chain for deteriorating items with up-stream and down-stream trade credits

    Science.gov (United States)

    Mahata, Gour Chandra

    2015-09-01

    In practice, the supplier often offers the retailers a trade credit period and the retailer in turn provides a trade credit period to her/his customer to stimulate sales and reduce inventory. From the retailer's perspective, granting trade credit not only increases sales and revenue but also increases opportunity cost (i.e., the capital opportunity loss during credit period) and default risk (i.e., the percentage that the customer will not be able to pay off his/her debt obligations). Hence, how to determine credit period is increasingly recognized as an important strategy to increase retailer's profitability. Also, the selling items such as fruits, fresh fishes, gasoline, photographic films, pharmaceuticals and volatile liquids deteriorate continuously due to evaporation, obsolescence and spoilage. In this paper, we propose an economic order quantity model for the retailer where (1) the supplier provides an up-stream trade credit and the retailer also offers a down-stream trade credit, (2) the retailer's down-stream trade credit to the buyer not only increases sales and revenue but also opportunity cost and default risk, and (3) the selling items are perishable. Under these conditions, we model the retailer's inventory system as a profit maximization problem to determine the retailer's optimal replenishment decisions under the supply chain management. We then show that the retailer's optimal credit period and cycle time not only exist but also are unique. We deduce some previously published results of other researchers as special cases. Finally, we use some numerical examples to illustrate the theoretical results.

  4. Synthesis of a parallel data stream processor from data flow process networks

    NARCIS (Netherlands)

    Zissulescu-Ianculescu, Claudiu

    2008-01-01

    In this talk, we address the problem of synthesizing Process Network specifications to FPGA execution platforms. The process networks we consider are special cases of Kahn Process Networks. We call them COMPAAN Data Flow Process Networks (CDFPN) because they are provided by a translator called the

  5. Hydrography - Streams and Shorelines

    Data.gov (United States)

    California Natural Resource Agency — The hydrography layer consists of flowing waters (rivers and streams), standing waters (lakes and ponds), and wetlands -- both natural and manmade. Two separate...

  6. Time dependent emission line profiles in the radially streaming particle model of Seyfert galaxy nuclei and quasi-stellar objects

    Science.gov (United States)

    Hubbard, R.

    1974-01-01

    The radially-streaming particle model for broad quasar and Seyfert galaxy emission features is modified to include sources of time dependence. The results are suggestive of reported observations of multiple components, variability, and transient features in the wings of Seyfert and quasi-stellar emission lines.

  7. Quantifying diffuse pathways for overland flow between the roads and streams of the mountain ash forests of central Victoria Australia

    Science.gov (United States)

    Lane, Patrick N. J.; Hairsine, Peter B.; Croke, Jacky C.; Takken, Ingrid

    2006-06-01

    Limiting connectivity between road runoff sources and stream networks is crucial for preservation of water quality in forested environments. Where flow is non-eroding, the length of hillslope available to accommodate volumes of discharged water is the key to restricting connectivity. Hairsine et al. ([2002], Hydrological Processes 16: 2311-2327) proposed a probabilistic model of diffuse overland flow that predicted the hillslope lengths required to infiltrate road discharge, based on the concept of volume to breakthrough (Vbt). This paper extends this analysis to a different forest environment with the aim of testing the portability of the Hairsine et al. ([2002]) model. The volume of flow required to travel overland to a distance of 5 and 10 m (Vbt5 and Vbt10) from drainage outlets was measured in deep, highly conductive mountain soils in the Upper Tyers catchment, Victoria, Australia. Rainfall, hydraulic conductivity and soil depths contrasted markedly with those in the Hairsine et al. ([2002]) study, and represent an extreme in Australian forests. Statistical analyses revealed the population of Vbt5 to be indistinguishable from that observed by Hairsine et al. ([2002]), indicating the model is valid for a range of forest soils. There was no significant correlation of sediment plume length with site characteristics such as slope, width of flow, or existence of incised pathways. It is suggested there are universal properties of pathways draining tracks and roads, with bioturbation acting to restore available pore spaces filled by antecedent plumes. Drain discharge design criteria may be developed for local conditions using the Hairsine et al. ([2002]) model, providing a robust tool for protection of water quality in the siting of new forest roads, and maintenance of exiting roads and tracks.

  8. Removal of Lead Ions From Waste streams Using Flowing-Through Porous Electrodes

    International Nuclear Information System (INIS)

    El-Deab, M.S.; Saleh, M.M.; El-Anadouli, B.E.; Ateya, B.G.

    1999-01-01

    Packed bed electrodes, made of stacked screens, have been used as cathodes for the removal of lead ions from flowing alkaline electrolytes. We consider the coulombic efficiency ξ =ipb/(ipb+iH), and the collection efficiency given by ψ=i L (exp)/nFvc, where i L (exp) is the geometric limiting current for lead deposition. Two regions are defined in the current-potential relations, depending on whether hydrogen evolution does, or does not, contribute to the measured current, corresponding to ξ less than, or equal to, 100%, respectively. The geometric limiting current, i L (exp), increases with increase of v. The collection efficiency ψ increases as v decreases and/or L increases. Operating the cell at higher flow rates increases the overall coulombic efficiency, over a broader range of cell currents

  9. Real-time display of flow-pressure-volume loops.

    Science.gov (United States)

    Morozoff, P E; Evans, R W

    1992-01-01

    Graphic display of respiratory waveforms can be valuable for monitoring the progress of ventilated patients. A system has been developed that can display flow-pressure-volume loops as derived from a patient's respiratory circuit in real time. It can also display, store, print, and retrieve ventilatory waveforms. Five loops can be displayed at once: current, previous, reference, "ideal," and previously saved. Two components, the data-display device (DDD) and the data-collection device (DCD), comprise the system. An IBM 286/386 computer with a graphics card (VGA) and bidirectional parallel port is used for the DDD; an eight-bit microprocessor card and an A/D convertor card make up the DCD. A real-time multitasking operating system was written to control the DDD, while the DCD operates from in-line assembly code. The DCD samples the pressure and flow sensors at 100 Hz and looks for a complete flow waveform pattern based on flow slope. These waveforms are then passed to the DDD via the mutual parallel port. Within the DDD a process integrates the flow to create a volume signal and performs a multilinear regression on the pressure, flow, and volume data to calculate the elastance, resistance, pressure offset, and coefficient of determination. Elastance, resistance, and offset are used to calculate Pr and Pc where: Pr[k] = P[k]-offset-(elastance.V[k]) and Pc[k] = P[k]-offset-(resistance.F[k]). Volume vs. Pc and flow vs. Pr can be displayed in real time. Patient data from previous clinical tests were loaded into the device to verify the software calculations. An analog waveform generator was used to simulate flow and pressure waveforms that validated the system.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Riparian woodland encroachment following flow regulation: a comparative study of Mediterranean and Boreal streams

    Directory of Open Access Journals (Sweden)

    Dolores Bejarano M.

    2011-10-01

    Full Text Available Water development accompanying mankind development has turned rivers into endangered ecosystems. Improving the understanding of ecological responses to river management actions is a key issue for assuring sustainable water management. However, few studies have been published where ecological metrics have been quantified in response to various degrees of flow alteration. In this work, changes in natural distribution of trees and shrubs within the riparian corridor (as indicator of the ecological status of the fluvial ecosystem were quantified at multiple sites along a flow alteration gradient (as indicator of impact along two regulated river reaches, one Boreal and the other Mediterranean, each downstream of a dam. Based on the obtained relationships we evaluated differences in response trends related to local physico-climatic factors of the two biomes and regarding to differing life-forms. Woody vegetation establishment patterns represented objective indicators of ecological responses to flow alteration. We found different responses between life-forms. Both trees and shrubs migrated downwards to the channel after dam closure, but shrubs were most impacted under higher degrees of flow alteration in terms of lateral movement. In addition, our results show clear longitudinal recovery trends of natural patterns of tree and shrub distribution corresponding to a decrease in intensity of hydrologic alteration in the Boreal river. However, vegetation encroachment persisted along the entire Mediterranean study reach. This may result from a relatively low gradient of decrease of hydrologic alteration with distance from the dam, coupled with other overlapping pressures and the mediating effect of physico-climatic characteristics on vegetation responses.

  11. Radiation Effects on the Flow and Heat Transfer over a Moving Plate in a Parallel Stream

    International Nuclear Information System (INIS)

    Ishak, Anuar

    2009-01-01

    Effects of thermal radiation on the steady laminar boundary layer flow over a moving plate in a moving fluid is investigated. Under certain conditions, the present problem reduces to the classical Blasius and Sakiadis problems. It is found that dual solutions exist when the plate and the fluid move in the opposite directions. Moreover, the existence of thermal radiation is to reduce the heat transfer rate at the surface. (fundamental areas of phenomenology (including applications))

  12. Batch Scheduling for Hybrid Assembly Differentiation Flow Shop to Minimize Total Actual Flow Time

    Science.gov (United States)

    Maulidya, R.; Suprayogi; Wangsaputra, R.; Halim, A. H.

    2018-03-01

    A hybrid assembly differentiation flow shop is a three-stage flow shop consisting of Machining, Assembly and Differentiation Stages and producing different types of products. In the machining stage, parts are processed in batches on different (unrelated) machines. In the assembly stage, each part of the different parts is assembled into an assembly product. Finally, the assembled products will further be processed into different types of final products in the differentiation stage. In this paper, we develop a batch scheduling model for a hybrid assembly differentiation flow shop to minimize the total actual flow time defined as the total times part spent in the shop floor from the arrival times until its due date. We also proposed a heuristic algorithm for solving the problems. The proposed algorithm is tested using a set of hypothetic data. The solution shows that the algorithm can solve the problems effectively.

  13. Sleep Management on Multiple Machines for Energy and Flow Time

    DEFF Research Database (Denmark)

    Chan, Sze-Hang; Lam, Tak-Wah; Lee, Lap Kei

    2011-01-01

    In large data centers, determining the right number of operating machines is often non-trivial, especially when the workload is unpredictable. Using too many machines would waste energy, while using too few would affect the performance. This paper extends the traditional study of online flow-time...... scheduling on multiple machines to take sleep management and energy into consideration. Specifically, we study online algorithms that can determine dynamically when and which subset of machines should wake up (or sleep), and how jobs are dispatched and scheduled. We consider schedules whose objective...... is to minimize the sum of flow time and energy, and obtain O(1)-competitive algorithms for two settings: one assumes machines running at a fixed speed, and the other allows dynamic speed scaling to further optimize energy usage. Like the previous work on the tradeoff between flow time and energy, the analysis...

  14. Accurate and efficient calculation of response times for groundwater flow

    Science.gov (United States)

    Carr, Elliot J.; Simpson, Matthew J.

    2018-03-01

    We study measures of the amount of time required for transient flow in heterogeneous porous media to effectively reach steady state, also known as the response time. Here, we develop a new approach that extends the concept of mean action time. Previous applications of the theory of mean action time to estimate the response time use the first two central moments of the probability density function associated with the transition from the initial condition, at t = 0, to the steady state condition that arises in the long time limit, as t → ∞ . This previous approach leads to a computationally convenient estimation of the response time, but the accuracy can be poor. Here, we outline a powerful extension using the first k raw moments, showing how to produce an extremely accurate estimate by making use of asymptotic properties of the cumulative distribution function. Results are validated using an existing laboratory-scale data set describing flow in a homogeneous porous medium. In addition, we demonstrate how the results also apply to flow in heterogeneous porous media. Overall, the new method is: (i) extremely accurate; and (ii) computationally inexpensive. In fact, the computational cost of the new method is orders of magnitude less than the computational effort required to study the response time by solving the transient flow equation. Furthermore, the approach provides a rigorous mathematical connection with the heuristic argument that the response time for flow in a homogeneous porous medium is proportional to L2 / D , where L is a relevant length scale, and D is the aquifer diffusivity. Here, we extend such heuristic arguments by providing a clear mathematical definition of the proportionality constant.

  15. Age and admission times as predictive factors for failure of admissions to discharge-stream short-stay units.

    Science.gov (United States)

    Shetty, Amith L; Shankar Raju, Savitha Banagar; Hermiz, Arsalan; Vaghasiya, Milan; Vukasovic, Matthew

    2015-02-01

    Discharge-stream emergency short-stay units (ESSU) improve ED and hospital efficiency. Age of patients and time of hospital presentations have been shown to correlate with increasing complexity of care. We aim to determine whether an age and time cut-off could be derived to subsequently improve short-stay unit success rates. We conducted a retrospective audit on 6703 (5522 inclusions) patients admitted to our discharge-stream short-stay unit. Patients were classified as appropriate or inappropriate admissions, and deemed successful if discharged out of the unit within 24 h; and failures if they needed inpatient admission into the hospital. We calculated short-stay unit length of stay for patients in each of these groups. A 15% failure rate was deemed as acceptable key performance indicator (KPI) for our unit. There were 197 out of 4621 (4.3%, 95% CI 3.7-4.9%) patients up to the age of 70 who failed admission to ESSU compared with 67 out of 901 (7.4%, 95% CI 5.9-9.3%, P 70 years of age have higher rates of failure after admission to discharge-stream ESSU. Although in appropriately selected discharge-stream patients, no age group or time-band of presentation was associated with increased failure rate beyond the stipulated KPI. © 2014 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  16. Addressing BI Transactional Flows in the Real-Time Enterprise Using GoldenGate TDM

    Science.gov (United States)

    Pareek, Alok

    It's time to visit low latency and reliable real-time (RT) infrastructures to support next generation BI applications instead of continually debating the need and notion of real-time. The last few years have illuminated some key paradigms affecting data management. The arguments put forth to move away from traditional DBMS architectures have proven persuasive - and specialized architectural data stores are being adopted in the industry [1]. The change from traditional database pull methods towards intelligent routing/push models is underway, causing applications to be redesigned, redeployed, and re-architected. One direct result of this is that despite original warnings about replication [2] - enterprises continue to deploy multiple replicas to support both performance, and high availability of RT applications, with an added complexity around manageability of heterogeneous computing systems. The enterprise is overflowing with data streams that require instantaneous processing and integration, to deliver faster visibility and invoke conjoined actions for RT decision making, resulting in deployment of advanced BI applications as can be seen by stream processing over RT feeds from operational systems for CEP [3]. Given these various paradigms, a multitude of new challenges and requirements have emerged, thereby necessitating different approaches to management of RT applications for BI. The purpose of this paper is to offer a viewpoint on how RT affects critical operational applications, evolves the weight of non-critical applications, and pressurizes availability/data-movement requirements in the underlying infrastructure. I will discuss how the GoldenGate TDM platform is being deployed within the RTE to manage some of these challenges particularly around RT dissemination of transactional data to reduce latency in data integration flows, to enable real-time reporting/DW, and to increase availability of underlying operational systems. Real world case studies will be

  17. StreamMap: Smooth Dynamic Visualization of High-Density Streaming Points.

    Science.gov (United States)

    Li, Chenhui; Baciu, George; Han, Yu

    2018-03-01

    Interactive visualization of streaming points for real-time scatterplots and linear blending of correlation patterns is increasingly becoming the dominant mode of visual analytics for both big data and streaming data from active sensors and broadcasting media. To better visualize and interact with inter-stream patterns, it is generally necessary to smooth out gaps or distortions in the streaming data. Previous approaches either animate the points directly or present a sampled static heat-map. We propose a new approach, called StreamMap, to smoothly blend high-density streaming points and create a visual flow that emphasizes the density pattern distributions. In essence, we present three new contributions for the visualization of high-density streaming points. The first contribution is a density-based method called super kernel density estimation that aggregates streaming points using an adaptive kernel to solve the overlapping problem. The second contribution is a robust density morphing algorithm that generates several smooth intermediate frames for a given pair of frames. The third contribution is a trend representation design that can help convey the flow directions of the streaming points. The experimental results on three datasets demonstrate the effectiveness of StreamMap when dynamic visualization and visual analysis of trend patterns on streaming points are required.

  18. Quantum dynamical time evolutions as stochastic flows on phase space

    International Nuclear Information System (INIS)

    Combe, P.; Rodriguez, R.; Guerra, F.; Sirigue, M.; Sirigue-Collin, M.

    1984-01-01

    We are mainly interested in describing the time development of the Wigner functions by means of stochastic processes. In the second section we recall the main properties of the Wigner functions as well as those of their Fourier transform. In the next one we derive the evolution equation of these functions for a class of Hamiltonians and we give a probabilistic expression for the solution of these equations by means of a stochastic flow in phase space which reminds of the classical flows. In the last section we remark that the previously defined flow can be extended to the bounded continuous functions on phase space and that this flow conserves the cone generated by the Wigner functions. (orig./HSI)

  19. The Influence of Flow and Bed Slope on Gas Transfer in Steep Streams and Their Implications for Evasion of CO2

    Science.gov (United States)

    Maurice, L.; Rawlins, B. G.; Farr, G.; Bell, R.; Gooddy, D. C.

    2017-11-01

    The evasion of greenhouse gases (including CO2, CH4, and N2O) from streams and rivers to the atmosphere is an important process in global biogeochemical cycles, but our understanding of gas transfer in steep (>10%) streams, and under varying flows, is limited. We investigated gas transfer using combined tracer injections of SF6 and salt. We used a novel experimental design in which we compared four very steep (18.4-29.4%) and four moderately steep (3.7-7.6%) streams and conducted tests in each stream under low flow conditions and during a high-discharge event. Most dissolved gas evaded over short distances ( 100 and 200-400 m, respectively), so accurate estimates of evasion fluxes will require sampling of dissolved gases at these scales to account for local sources. We calculated CO2 gas transfer coefficients (KCO2) and found statistically significant differences between larger KCO2 values for steeper (mean 0.465 min-1) streams compared to those with shallower slopes (mean 0.109 min-1). Variations in flow had an even greater influence. KCO2 was substantially larger under high (mean 0.497 min-1) compared to low flow conditions (mean 0.077 min-1). We developed a statistical model to predict KCO2 using values of streambed slope × discharge which accounted for 94% of the variation. We show that two models using slope and velocity developed by Raymond et al. (2012) for streams and rivers with shallower slopes also provide reasonable estimates of our CO2 gas transfer velocities (kCO2; m d-1). We developed a robust field protocol which could be applied in future studies.

  20. Three-Dimensional Numerical Modelling of Flow and Sediment Transport for Field Scale Application of Stream Barbs at Sawmill Creek, Ottawa

    Science.gov (United States)

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

    2009-05-01

    Stream barbs (a type of submerged groyne or spur dike) are low-profile linear rock structures that prevent the erosion of stream banks by redirecting high velocity flow away from the bank. Stream barbs are becoming a popular method for stream bank protection as they can be built at a relatively low cost and provide added ecological benefit. The design and construction of stream barbs in Sawmill Creek, a small urban stream in the city of Ottawa, Canada, will serve as a demonstration project for the use of barbs as a bank stabilization technique that will contribute to the rehabilitation of urban creeks while reducing erosion threats to property and infrastructure. As well as providing bank protection, these structures promote vegetated stream banks, create resting pools and scour holes for fish habitat, and increase bio-diversity for aquatic species. Despite these benefits, stream barbs are not a common means of stream bank protection in Canada, due largely to a lack of suitable design guidelines. The overall goal of stream habitat restoration in incising channel systems should be to accelerate natural processes of channel equilibrium recovery, riparian re-vegetation, and stream-floodplain interaction. Incorporating stream barbs, instead of traditional bank protection measures, attempts to achieve these goals. A three-dimensional numerical model: 'Simulation in Intakes with Multiblock option' (SSIIM), was used to model the effects of placing a series of stream barbs along an unstable section of Sawmill Creek. The average bankfull depth, width, and discharge of the creek are 1.2 m, 7.5 m, and 9 m3/s respectively. The model was used to assess various design alternatives for a series of seven stream barbs at two consecutive channel bends requiring stabilization measures along their outer banks. Design criteria were principally based on the reduction of velocity, shear stress and subsequent erosion at the outside bank of each bend, and on the relocation of a new thalweg

  1. Complex blood flow quantification using real-time in vivo vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Per, Haugaard

    A new method to define and quantify complex blood flow is presented. The standard deviations of real-time in vivo vector flow angle estimates are used. Using vector flow ultrasound imaging both carotid bifurcations of two healthy volunteers were scanned. Scanning was performed with a 7.6 MHz linear...... transducer (8670, B-K Medical, Denmark) and a commercial vector flow ultrasound scanner (ProFocus 2202, B-K Medical). Eight video sequences of one cardiac cycle were obtained. In every frame boxes were placed to define the common carotid artery(box1) and the carotid bulb(box2). The standard deviation...... for the vector angle estimates was calculated for each box in every frame. For comparison three ultrasound experts evaluated the presence of complex flow in every box. The trial was blinded. For every sequence the mean standard deviation of the vector angle estimates were calculated for box1 {39...

  2. The stream flow rate measurement using tracer techniques at the Kemubu Agricultural Development Authority (KADA), Kelantan

    International Nuclear Information System (INIS)

    Daud Mohammad; Abd Razak Hamzah; Wan Abd Aziz Wan Mohamad; Juhari Yusoff; Wan Zakaria Wan Mohd Tahir

    1985-01-01

    Measuring the flow rate of a water course is one of the basic operations in hydrology, being of general relevance to water problems and of particular importance in the planning of water control schemes. The techniques commonly used in streamflow gauging are either by a current meter of tracer dilution method. This paper describes the latter technique in which radioisotope Tc-99m was used as a tracer in streamflow measurements performed in 1983 in a few selected irrigation canals and pump house under the Kemubu Agriculture Development Authority (KADA), Kelantan. Total count technique and peak-to-peak method were adopted in this study. (author)

  3. Generalized Skew Coefficients of Annual Peak Flows for Rural, Unregulated Streams in West Virginia

    Science.gov (United States)

    Atkins, John T.; Wiley, Jeffrey B.; Paybins, Katherine S.

    2009-01-01

    Generalized skew was determined from analysis of records from 147 streamflow-gaging stations in or near West Virginia. The analysis followed guidelines established by the Interagency Advisory Committee on Water Data described in Bulletin 17B, except that stations having 50 or more years of record were used instead of stations with the less restrictive recommendation of 25 or more years of record. The generalized-skew analysis included contouring, averaging, and regression of station skews. The best method was considered the one with the smallest mean square error (MSE). MSE is defined as the following quantity summed and divided by the number of peaks: the square of the difference of an individual logarithm (base 10) of peak flow less the mean of all individual logarithms of peak flow. Contouring of station skews was the best method for determining generalized skew for West Virginia, with a MSE of about 0.2174. This MSE is an improvement over the MSE of about 0.3025 for the national map presented in Bulletin 17B.

  4. Real-Time Detection Methods to Monitor TRU Compositions in UREX+Process Streams

    Energy Technology Data Exchange (ETDEWEB)

    McDeavitt, Sean; Charlton, William; Indacochea, J Ernesto; taleyarkhan, Rusi; Pereira, Candido

    2013-03-01

    The U.S. Department of Energy has developed advanced methods for reprocessing spent nuclear fuel. The majority of this development was accomplished under the Advanced Fuel Cycle Initiative (AFCI), building on the strong legacy of process development R&D over the past 50 years. The most prominent processing method under development is named UREX+. The name refers to a family of processing methods that begin with the Uranium Extraction (UREX) process and incorporate a variety of other methods to separate uranium, selected fission products, and the transuranic (TRU) isotopes from dissolved spent nuclear fuel. It is important to consider issues such as safeguards strategies and materials control and accountability methods. Monitoring of higher actinides during aqueous separations is a critical research area. By providing on-line materials accountability for the processes, covert diversion of the materials streams becomes much more difficult. The importance of the nuclear fuel cycle continues to rise on national and international agendas. The U.S. Department of Energy is evaluating and developing advanced methods for safeguarding nuclear materials along with instrumentation in various stages of the fuel cycle, especially in material balance areas (MBAs) and during reprocessing of used nuclear fuel. One of the challenges related to the implementation of any type of MBA and/or reprocessing technology (e.g., PUREX or UREX) is the real-time quantification and control of the transuranic (TRU) isotopes as they move through the process. Monitoring of higher actinides from their neutron emission (including multiplicity) and alpha signatures during transit in MBAs and in aqueous separations is a critical research area. By providing on-line real-time materials accountability, diversion of the materials becomes much more difficult. The objective of this consortium was to develop real time detection methods to monitor the efficacy of the UREX+ process and to safeguard the separated

  5. The significance and lag-time of deep through flow: an example from a small, ephemeral catchment with contrasting soil types in the Adelaide Hills, South Australia

    Directory of Open Access Journals (Sweden)

    J. VanLeeuwen

    2009-07-01

    Full Text Available The importance of deep soil-regolith through flow in a small (3.4 km2 ephemeral catchment in the Adelaide Hills of South Australia was investigated by detailed hydrochemical analysis of soil water and stream flow during autumn and early winter rains. In this Mediterranean climate with strong summer moisture deficits, several significant rainfalls are required to generate soil through flow and stream flow [in ephemeral streams]. During autumn 2007, a large (127 mm drought-breaking rain occurred in April followed by significant May rains; most of this April and May precipitation occurred prior to the initiation of stream flow in late May. These early events, especially the 127 mm April event, had low stable water isotope values compared with later rains during June and July and average winter precipitation. Thus, this large early autumn rain event with low isotopic values (δ18O, δD provided an excellent natural tracer. During later June and July rainfall events, daily stream and soil water samples were collected and analysed. Results from major and trace elements, water isotopes (δ18O, δD, and dissolved organic carbon analysis clearly demonstrate that a large component of this early April and May rain was stored and later pushed out of deep soil and regolith zones. This pre-event water was identified in the stream as well as identified in deep soil horizons due to its different isotopic signature which contrasted sharply with the June–July event water. Based on this data, the soil-regolith hydrologic system for this catchment has been re-thought. The catchment area consists of about 60% sandy and 40% clayey soils. Regolith flow in the sandy soil system and not the clayey soil system is now thought to dominate the deep subsurface flow in this catchment. The clayey texture contrast soils had rapid response to rain events and saturation excess overland flow. The sandy soils had delayed soil through flow and

  6. Snow Cover, Snowmelt Timing and Stream Power in the Wind River Range, Wyoming

    Science.gov (United States)

    Hall, Dorothy K.; Foster, James L.; DiGirolamo, Nicolo E.; Riggs, George A.

    2011-01-01

    Earlier onset of springtime weather, including earlier snowmelt, has been documented in the western United States over at least the last 50 years. Because the majority (is greater than 70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack (and shrinking glaciers) has important implications for the management of streamflow. The amount of water in a snowpack influences stream discharge which can also influence erosion and sediment transport by changing stream power, or the rate at which a stream can do work, such as move sediment and erode the stream bed. The focus of this work is the Wind River Range (WRR) in west-central Wyoming. Ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover, cloud-gap-filled (CGF) map products and 30 years of discharge and meteorological station data are studied. Streamflow data from streams in WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades, though no trend of either lower streamflow or earlier snowmelt was observed within the decade of the 2000s. Results show a statistically-significant trend at the 95% confidence level (or higher) of increasing weekly maximum air temperature (for three out of the five meteorological stations studied) in the decade of the 1970s, and also for the 40-year study period as a whole. The extent of snow-cover (percent of basin covered) derived from the lowest elevation zone (2500-3000 m) of the WRR, using MODIS CGF snow-cover maps, is strongly correlated with maximum monthly discharge on 30 April, where Spearman's Rank correlation, rs,=0.89 for the decade of the 2000s. We also investigated stream power for Bull Lake Creek above Bull Lake; and found a trend (significant at the 90% confidence level) toward reduced stream power from 1970 to 2009. Observed changes in streamflow and stream power may be related to increasing weekly maximum air temperature

  7. Complexity analysis of the turbulent environmental fluid flow time series

    Science.gov (United States)

    Mihailović, D. T.; Nikolić-Đorić, E.; Drešković, N.; Mimić, G.

    2014-02-01

    We have used the Kolmogorov complexities, sample and permutation entropies to quantify the randomness degree in river flow time series of two mountain rivers in Bosnia and Herzegovina, representing the turbulent environmental fluid, for the period 1926-1990. In particular, we have examined the monthly river flow time series from two rivers (the Miljacka and the Bosnia) in the mountain part of their flow and then calculated the Kolmogorov complexity (KL) based on the Lempel-Ziv Algorithm (LZA) (lower-KLL and upper-KLU), sample entropy (SE) and permutation entropy (PE) values for each time series. The results indicate that the KLL, KLU, SE and PE values in two rivers are close to each other regardless of the amplitude differences in their monthly flow rates. We have illustrated the changes in mountain river flow complexity by experiments using (i) the data set for the Bosnia River and (ii) anticipated human activities and projected climate changes. We have explored the sensitivity of considered measures in dependence on the length of time series. In addition, we have divided the period 1926-1990 into three subintervals: (a) 1926-1945, (b) 1946-1965, (c) 1966-1990, and calculated the KLL, KLU, SE, PE values for the various time series in these subintervals. It is found that during the period 1946-1965, there is a decrease in their complexities, and corresponding changes in the SE and PE, in comparison to the period 1926-1990. This complexity loss may be primarily attributed to (i) human interventions, after the Second World War, on these two rivers because of their use for water consumption and (ii) climate change in recent times.

  8. Do cortical midline variability and low frequency fluctuations mediate William James' "Stream of Consciousness"? "Neurophenomenal Balance Hypothesis" of "Inner Time Consciousness".

    Science.gov (United States)

    Northoff, Georg

    2014-11-01

    William James famously characterized consciousness by 'stream of consciousness' which describes the temporal continuity and flow of the contents of consciousness in our 'inner time consciousness'. More specifically he distinguished between "substantive parts", the contents of consciousness, and "transitive parts", the linkages between different contents. While much research has recently focused on the substantive parts, the neural mechanisms underlying the transitive parts and their characterization by the balance between 'sensible continuity' and 'continuous change' remain unclear. The aim of this paper is to develop so-called neuro-phenomenal hypothesis about specifically the transitive parts and their two phenomenal hallmark features, sensible continuity and continuous change in 'inner time consciousness'. Based on recent findings, I hypothesize that the cortical midline structures and their high degree of variability and strong low frequency fluctuations play an essential role in mediating the phenomenal balance between sensible continuity and continuous change. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Tempered fractional time series model for turbulence in geophysical flows

    Science.gov (United States)

    Meerschaert, Mark M.; Sabzikar, Farzad; Phanikumar, Mantha S.; Zeleke, Aklilu

    2014-09-01

    We propose a new time series model for velocity data in turbulent flows. The new model employs tempered fractional calculus to extend the classical 5/3 spectral model of Kolmogorov. Application to wind speed and water velocity in a large lake are presented, to demonstrate the practical utility of the model.

  10. Tempered fractional time series model for turbulence in geophysical flows

    International Nuclear Information System (INIS)

    Meerschaert, Mark M; Sabzikar, Farzad; Phanikumar, Mantha S; Zeleke, Aklilu

    2014-01-01

    We propose a new time series model for velocity data in turbulent flows. The new model employs tempered fractional calculus to extend the classical 5/3 spectral model of Kolmogorov. Application to wind speed and water velocity in a large lake are presented, to demonstrate the practical utility of the model. (paper)

  11. Time-Dependent Natural Convection Couette Flow of Heat ...

    African Journals Online (AJOL)

    Time-Dependent Natural Convection Couette Flow of Heat Generating/Absorbing Fluid between Vertical Parallel Plates Filled With Porous Material. ... The numerical simulation conducted for some saturated liquids reveled that at t ≥ Pr the steady and unsteady state velocities (as well as the temperature of the fluid) ...

  12. Hydrological modeling of stream flow in small Mediterranean dams and impact of climate change : case study of wadi Rmel catchment

    Science.gov (United States)

    Habaieb, Hamadi; Hermassi, Taoufik; Moncef Masmoudi, Mohamed; Ben Mechlia, Nétij

    2015-04-01

    Northern Tunisia is characterized by a semi-arid climate with an irregular and high spatial variability of rainfall. This situation is expected to aggravate under the expected increase of temperature and modification of rainfall regime predicted by most climate models for the Mediterranean region. Water is a major limiting factor for agriculture in Tunisia and mobilization of surface water resources is approaching its maximum. Dams are installed on almost all large watersheds and concerned also medium size and small ones. Hydrological functioning of such structures and their capacity to satisfy user's demand under the changing climate will be addressed using simple models and results will be discussed in this paper. The small catchment of Wadi Rmel is considered here for methodological development. This watershed (675 Km2) is situated in North-East Tunisia with average annual rainfall of 420 mm and was equipped in 1998 with a small dam. Data on rainfall collected at 12 rainfall stations during the period 1908 - 2012 are analyzed and used to build a coherent series of monthly rainfalls and spatially averaged on the watershed by the Thiessen method. In a second step, rainfall-runoff modeling was used to estimate runoff and water budget of the dam. Tow rainfall-runoff models GR2M and SWAT were considered and evaluated when using i) the rainfall observed at the dam and ii) the average rainfall on the watershed. The observed and simulated level in the dam were compared for both models and situations. Results showed that taking into account the spatial distribution of rainfall improved the simulation of stream flows and that SWAT model performs better than GR2M. The use of such models to make prediction of stream flow using downscaled climatic data from GCM will be discussed. Analysis of the results considering tow standardized sets of future greenhouse gas emissions used by the General Circulation Models for the IPCC 5th approximation RCP4.5 and RCP8.5 and three future

  13. Relation between Streaming Potential and Streaming Electrification Generated by Streaming of Water through a Sandwich-type Cell

    OpenAIRE

    Maruyama, Kazunori; Nikaido, Mitsuru; Hara, Yoshinori; Tanizaki, Yoshie

    2012-01-01

    Both streaming potential and accumulated charge of water flowed out were measured simultaneously using a sandwich-type cell. The voltages generated in divided sections along flow direction satisfied additivity. The sign of streaming potential agreed with that of streaming electrification. The relation between streaming potential and streaming electrification was explained from a viewpoint of electrical double layer in glass-water interface.

  14. Fishy Business: Response of Stream Fish Assemblages to Small Hydro-power Plant Induced Flow Alteration in the Western Ghats, Karnataka

    Science.gov (United States)

    Rao, S. T.; Krishnaswamy, J.; Bhalla, R. S.

    2017-12-01

    Alteration of natural flow regimes is considered as a major threat to freshwater fish assemblages as it disturbs the water quality and micro-habitat features of rivers. Small hydro-power (SHP), which is being promoted as a clean and green substitute for large hydro-power generation, alters the natural flow regime of head-water streams by flow diversion and regulation. The effects of altered flow regime on tropical stream fish assemblages, driven by seasonality induced perturbations to water quality and microhabitat parameters are largely understudied. My study examined the potential consequences of flow alteration by SHPs on fish assemblages in two tributaries of the west-flowing Yettinahole River which flows through the reserved forests of Sakleshpur in the Western Ghats of Karnataka. The flow in one of the tributaries followed natural flow regime while the other comprised three regimes: a near-natural flow regime above the dam, rapidly varying discharge below the dam and a dewatered regime caused by flow diversion. The study found that the altered flow regime differed from natural flow regime in terms of water quality, microhabitat heterogeneity and fish assemblage response, each indicative of the type of flow alteration. Fish assemblage in the natural flow regime was characterized by a higher catch per site, a strong association of endemic and trophic specialist species. The flow regime above the dam was found to mimic some components of the natural flow regime, both ecological and environmental. Non endemic, generalist and pool tolerant species were associated with the dewatered regime. There was a lack of strong species-regime association and an overall low catch per site for the flow regulated regime below the dam. This study highlights the consequences of altered flows on the composition of freshwater fish assemblages and portrays the potential of freshwater fish as indicators of the degree and extent of flow alteration. The study recommends the need for

  15. Development and test of a free-streaming readout chain for the CBM time of flight wall

    International Nuclear Information System (INIS)

    Loizeau, Pierre-Alain

    2014-01-01

    This thesis presents the development and test of a free-streaming readout chain for the Time of Flight (TOF) Wall of the Compressed Baryonic Matter (CBM) experiment. In order to contribute to the exploration of the phase diagram of strongly interacting matter, CBM aims at the measurement of rare probes, whose yields and phase space distributions are significantly influenced by their environment. Many of the possible signals, of which the antiprotons was investigated within this thesis, require an excellent Particle Identification (PID) and a new readout paradigm called free-streaming. In CBM, the PID for charged particles is provided by a TOF wall based on Multi-gap Resistive Plate Chambers (MRPC). Within the thesis, a central component of the TOF readout chain, the free-streaming ASIC-TDC, was evaluated and pushed from the prototype level to a close to final design, for which it could be demonstrated that it fulfill all the CBM requirements: resolution, rate capability and stability. Additionally, the CBM TOF software in the CBMROOT software framework was reorganized to merge the processing and analysis of real and simulated data. A data unpacker and a realistic digitizer were implemented with a common output data format. The digitizer was used to estimate the data rates and number of components in a free-streaming readout chain for the full wall.

  16. Stream Flow Simulation of a Snow-Fed Mountainous Basin Using the SWAT Model

    Science.gov (United States)

    Shukla, S.; Kansal, M. L.; Jain, S. K.

    2017-12-01

    Hydrological budget of the Satluj River (a major tributary of Indus river system) in Western Himalaya, is dominated by monsoonal rainfall and snowmelt during the non-monsoon months. The river watershed experiences extensive snowfall in the winters and snowmelt runoff substantially contributes to the streamflow of the river in the spring and summer months. In order to understand the hydrologic response of Satluj basin, hydrological modeling study is carried out using a semi distributed hydrological model Soil and Water Assessment Tool (SWAT), for the period of thirty years (1985-2014). The basic intent of this study is to derive the parameters required for runoff modeling using the geospatial database. The Sequential Uncertainty Fitting (SUFI-2) algorithm is used to calibrate and validate the model and incorporate uncertainties in the analysis. The results are validated with the observed daily streamflow data at Rampur, in terms of Nash-Sutcliffe Coefficient (NSC), R2 and Root Mean Square Error (RMSE). Further, the snowmelt-runoff mechanism is modelled by relating the temperature changes to the elevation band in the basin. The northern part of the basin and the south part of the basin on the high elevation zones have the coldest maximum temperatures that is about 7°C. It is found that the average contribution of snow and glacier runoff in the annual flow of the Satluj River at Rampur is about 66% and remaining 34% is from rainfall.

  17. Dynamic ADMM for Real-time Optimal Power Flow: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-02-23

    This paper considers distribution networks featuring distributed energy resources (DERs), and develops a dynamic optimization method to maximize given operational objectives in real time while adhering to relevant network constraints. The design of the dynamic algorithm is based on suitable linearizations of the AC power flow equations, and it leverages the so-called alternating direction method of multipliers (ADMM). The steps of the ADMM, however, are suitably modified to accommodate appropriate measurements from the distribution network and the DERs. With the aid of these measurements, the resultant algorithm can enforce given operational constraints in spite of inaccuracies in the representation of the AC power flows, and it avoids ubiquitous metering to gather the state of non-controllable resources. Optimality and convergence of the propose algorithm are established in terms of tracking of the solution of a convex surrogate of the AC optimal power flow problem.

  18. Cross-flow filtration during the washing of a simulated radioactive waste stream

    International Nuclear Information System (INIS)

    MARK R., DUIGNAN

    2005-01-01

    Bechtel National, Inc. has been contracted by the Department of Energy to design a Waste Treatment and Immobilization Plant (WTP) to stabilize liquid radioactive waste that is stored at the Hanford Site as part of the River Protection Project (RPP). Because of its experience with radioactive waste stabilization, the Savannah River National Laboratory (SRNL) of the Westinghouse Savannah River Company is working with Bechtel and Washington Group International, to help design and test certain parts of the waste treatment facility. One part of the process is the separation of radioactive solids from the liquid wastes by cross-flow ultrafiltration. To test this process a cross-flow filter was used that was prototypic in porosity, length, and diameter, along with a simulated radioactive waste slurry, made to prototypically represent the chemical and physical characteristics of a Hanford waste in tank 241-AY-102/C-106. To mimic the filtration process the waste slurry undergoes several steps, including dewatering and washing. During dewatering the concentration of undissolved solids (UDS) of the simulated AY102/C106 waste is increased from 12 wt percent to at least 20 wt percent. Once at the higher concentration the waste must be washed to prepare for its eventual receipt in a High Level Radioactive Waste Melter to be vitrified. This paper describes the process of washing and filtering a batch of concentrated simulated waste in two cycles, which each containing 22 washing steps that used approximately 7.7 liters of a solution of 0.01 M NaOH per step. This will be the method used by the full-scale WTP to prepare the waste for vitrification. The first washing cycle started with the simulated waste that had a solids concentration of 20 wt percent UDS. This cycle began with a permeate filter flux of 0.015 gpm/ft2 (3.68 cm/hr) at 19.6 wt percent UDS with a density of 1.33 kg/L, and yield stress of 8.5 Pa. At the end of the 22 washing steps the permeate filter flux increased to

  19. The mass flow and proposed management of bisphenol A in selected Norwegian waste streams.

    Science.gov (United States)

    Arp, Hans Peter H; Morin, Nicolas A O; Hale, Sarah E; Okkenhaug, Gudny; Breivik, Knut; Sparrevik, Magnus

    2017-02-01

    Current initiatives for waste-handling in a circular economy favor prevention and recycling over incineration or landfilling. However, the impact of such a transition on environmental emissions of contaminants like bisphenol A (BPA) during waste-handling is not fully understood. To address this, a material flow analysis (MFA) was constructed for selected waste categories in Norway, for which the amount recycled is expected to increase in the future; glass, vehicle, electronic, plastic and combustible waste. Combined, 92tons/y of BPA are disposed of via these waste categories in Norway, with 98.5% associated with plastic and electronic waste. During the model year 2011, the MFA showed that BPA in these waste categories was destroyed through incineration (60%), exported for recycling into new products (35%), stored in landfills (4%) or released into the environment (1%). Landfilling led to the greatest environmental emissions (up to 13% of landfilled BPA), and incinerating the smallest (0.001% of incinerated BPA). From modelling different waste management scenarios, the most effective way to reduce BPA emissions are to incinerate BPA-containing waste and avoid landfilling it. A comparison of environmental and human BPA concentrations with CoZMoMAN exposure model estimations suggested that waste emissions are an insignificant regional source. Nevertheless, from monitoring studies, landfill emissions can be a substantial local source of BPA. Regarding the transition to a circular economy, it is clear that disposing of less BPA-containing waste and less landfilling would lead to lower environmental emissions, but several uncertainties remain regarding emissions of BPA during recycling, particularly for paper and plastics. Future research should focus on the fate of BPA, as well as BPA alternatives, in emerging reuse and recycling processes, as part of the transition to a circular economy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. StreamExplorer: A Multi-Stage System for Visually Exploring Events in Social Streams.

    Science.gov (United States)

    Wu, Yingcai; Chen, Zhutian; Sun, Guodao; Xie, Xiao; Cao, Nan; Liu, Shixia; Cui, Weiwei

    2017-10-18

    Analyzing social streams is important for many applications, such as crisis management. However, the considerable diversity, increasing volume, and high dynamics of social streams of large events continue to be significant challenges that must be overcome to ensure effective exploration. We propose a novel framework by which to handle complex social streams on a budget PC. This framework features two components: 1) an online method to detect important time periods (i.e., subevents), and 2) a tailored GPU-assisted Self-Organizing Map (SOM) method, which clusters the tweets of subevents stably and efficiently. Based on the framework, we present StreamExplorer to facilitate the visual analysis, tracking, and comparison of a social stream at three levels. At a macroscopic level, StreamExplorer uses a new glyph-based timeline visualization, which presents a quick multi-faceted overview of the ebb and flow of a social stream. At a mesoscopic level, a map visualization is employed to visually summarize the social stream from either a topical or geographical aspect. At a microscopic level, users can employ interactive lenses to visually examine and explore the social stream from different perspectives. Two case studies and a task-based evaluation are used to demonstrate the effectiveness and usefulness of StreamExplorer.Analyzing social streams is important for many applications, such as crisis management. However, the considerable diversity, increasing volume, and high dynamics of social streams of large events continue to be significant challenges that must be overcome to ensure effective exploration. We propose a novel framework by which to handle complex social streams on a budget PC. This framework features two components: 1) an online method to detect important time periods (i.e., subevents), and 2) a tailored GPU-assisted Self-Organizing Map (SOM) method, which clusters the tweets of subevents stably and efficiently. Based on the framework, we present Stream

  1. Applications of multiscale change point detections to monthly stream flow and rainfall in Xijiang River in southern China, part I: correlation and variance

    Science.gov (United States)

    Zhu, Yuxiang; Jiang, Jianmin; Huang, Changxing; Chen, Yongqin David; Zhang, Qiang

    2018-04-01

    This article, as part I, introduces three algorithms and applies them to both series of the monthly stream flow and rainfall in Xijiang River, southern China. The three algorithms include (1) normalization of probability distribution, (2) scanning U test for change points in correlation between two time series, and (3) scanning F-test for change points in variances. The normalization algorithm adopts the quantile method to normalize data from a non-normal into the normal probability distribution. The scanning U test and F-test have three common features: grafting the classical statistics onto the wavelet algorithm, adding corrections for independence into each statistic criteria at given confidence respectively, and being almost objective and automatic detection on multiscale time scales. In addition, the coherency analyses between two series are also carried out for changes in variance. The application results show that the changes of the monthly discharge are still controlled by natural precipitation variations in Xijiang's fluvial system. Human activities disturbed the ecological balance perhaps in certain content and in shorter spells but did not violate the natural relationships of correlation and variance changes so far.

  2. Controlling mixing and segregation in time periodic granular flows

    Science.gov (United States)

    Bhattacharya, Tathagata

    Segregation is a major problem for many solids processing industries. Differences in particle size or density can lead to flow-induced segregation. In the present work, we employ the discrete element method (DEM)---one type of particle dynamics (PD) technique---to investigate the mixing and segregation of granular material in some prototypical solid handling devices, such as a rotating drum and chute. In DEM, one calculates the trajectories of individual particles based on Newton's laws of motion by employing suitable contact force models and a collision detection algorithm. Recently, it has been suggested that segregation in particle mixers can be thwarted if the particle flow is inverted at a rate above a critical forcing frequency. Further, it has been hypothesized that, for a rotating drum, the effectiveness of this technique can be linked to the probability distribution of the number of times a particle passes through the flowing layer per rotation of the drum. In the first portion of this work, various configurations of solid mixers are numerically and experimentally studied to investigate the conditions for improved mixing in light of these hypotheses. Besides rotating drums, many studies of granular flow have focused on gravity driven chute flows owing to its practical importance in granular transportation and to the fact that the relative simplicity of this type of flow allows for development and testing of new theories. In this part of the work, we observe the deposition behavior of both mono-sized and polydisperse dry granular materials in an inclined chute flow. The effects of different parameters such as chute angle, particle size, falling height and charge amount on the mass fraction distribution of granular materials after deposition are investigated. The simulation results obtained using DEM are compared with the experimental findings and a high degree of agreement is observed. Tuning of the underlying contact force parameters allows the achievement

  3. Hydraulic Properties related to Stream Reaeration

    Energy Technology Data Exchange (ETDEWEB)

    Tsivoglou, E. C.; Wallace, J. R. [School of Civil Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

    1970-09-15

    The paper reports the results of recent and current field tracer experiments designed to investigate the relationships between the reaeration capacity of a flowing stream and the stream's hydraulic properties. The purpose of the studies is to develop models for the accurate prediction of stream reaeration capacity on the basis of observation of the associated hydraulic properties. The ability of a flowing stream to absorb oxygen from the overlying atmosphere is the principal process by which the stream is able to recover its dissolved oxygen resources once they have been depleted by bacterial degradation of organic wastes. Accurate knowledge of stream reaeration capacity is therefore a necessity in determining the required degree of waste treatment, and the associated costs, in any specific case. Oxygen absorption can only occur at the air-water interface, hence reaeration is a direct function of the rate of surface water replacement due to turbulent mixing. The latter is not directly observable, and so reaeration capacity has not been observable before the quite recent development of a gaseous radiotracer technique for field measurement of reaeration. This procedure involves the simultaneous use of three tracers, namely a fluorescent dye for time of flow, tritiated water for accurate dispersion measurement, and dissolved krypton-85 for measurement of gas transfer. Field results obtained by this technique are highly reproducible. Field tracer studies of the reaeration capacities of three medium-sized streams have been conducted over a total of about fifty river miles. Associated hydraulic properties such as stream flow, cross-sectional area, depth, velocity, hydraulic gradient and dispersion have also been measured. Features such as waterfalls, rapids and pools are included, and more than eighty observations of the reaeration capacities of individual stream reaches have been made. The paper reports the observed relationships between stream reaeration capacity and

  4. Hydraulic properties related to stream reaeration

    Energy Technology Data Exchange (ETDEWEB)

    Tsivoglou, E C; Wallace, J R [School of Civil Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

    1970-09-15

    The paper reports the results of recent and current field tracer experiments designed to investigate the relationships between the reaeration capacity of a flowing stream and the stream's hydraulic properties. The purpose of the studies is to develop models for the accurate prediction of stream reaeration capacity on the basis of observation of the associated hydraulic properties. The ability of a flowing stream to absorb oxygen from the overlying atmosphere is the principal process by which the stream is able to recover its dissolved oxygen resources once they have been depleted by bacterial degradation of organic wastes. Accurate knowledge of stream reaeration capacity is therefore a necessity in determining the required degree of waste treatment, and the associated costs, in any specific case. Oxygen absorption can only occur at the air-water interface, hence reaeration is a direct function of the rate of surface water replacement due to turbulent mixing. The latter is not directly observable, and so reaeration capacity has not been observable before the quite recent development of a gaseous radiotracer technique for field measurement of reaeration. This procedure involves the simultaneous use of three tracers, namely a fluorescent dye for time of flow, tritiated water for accurate dispersion measurement, and dissolved krypton-85 for measurement of gas transfer. Field results obtained by this technique are highly reproducible. Field tracer studies of the reaeration capacities of three medium-sized streams have been conducted over a total of about fifty river miles. Associated hydraulic properties such as stream flow, cross-sectional area, depth, velocity, hydraulic gradient and dispersion have also been measured. Features such as waterfalls, rapids and pools are included, and more than eighty observations of the reaeration capacities of individual stream reaches have been made. The paper reports the observed relationships between stream reaeration capacity and

  5. Lagrangian structures in time-periodic vortical flows

    Directory of Open Access Journals (Sweden)

    S. V. Kostrykin

    2006-01-01

    Full Text Available The Lagrangian trajectories of fluid particles are experimentally studied in an oscillating four-vortex velocity field. The oscillations occur due to a loss of stability of a steady flow and result in a regular reclosure of streamlines between the vortices of the same sign. The Eulerian velocity field is visualized by tracer displacements over a short time period. The obtained data on tracer motions during a number of oscillation periods show that the Lagrangian trajectories form quasi-regular structures. The destruction of these structures is determined by two characteristic time scales: the tracers are redistributed sufficiently fast between the vortices of the same sign and much more slowly transported into the vortices of opposite sign. The observed behavior of the Lagrangian trajectories is quantitatively reproduced in a new numerical experiment with two-dimensional model of the velocity field with a small number of spatial harmonics. A qualitative interpretation of phenomena observed on the basis of the theory of adiabatic chaos in the Hamiltonian systems is given. The Lagrangian trajectories are numerically simulated under varying flow parameters. It is shown that the spatial-temporal characteristics of the Lagrangian structures depend on the properties of temporal change in the streamlines topology and on the adiabatic parameter corresponding to the flow. The condition for the occurrence of traps (the regions where the Lagrangian particles reside for a long time is obtained.

  6. The Stream Flow Prediction Model Using Fuzzy Inference System and Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Mahmoud Mohammad RezapourTabari

    2013-03-01

    Full Text Available The aim of this study is the spatial prediction runoff using hydrometric and meteorological stations data. The research shows that usually there is a certain communication between the meteorological and hydrometric data of upstream basin and runoff rates in output basin. So, if can be extracted the rules related to historical data that recorded at stations, can be easily predicted runoff amount based on data measured. Accordingly, among the tools available, the fuzzy theory (with flexibility in developing fuzzy rules can be provide the knowledge lies in the observed data to parameters prediction in real time. So, in this research the fuzzy inference system has been used for estimating runoff rates at stations located in the Taleghan river downstream using rain gage stations and hydrometric stations upstream. Because the inappropriate values associated with membership functions, the fuzzy system model can not provide correct value for the prediction. In this study, a combination of intelligence-based optimization algorithm and fuzzy theory developed to accelerate and improve modeling. The result of proposed model, optimum values to each membership function that related to dependent and independent variable extracted and based on it’s the runoff rates in rivers downstream predicted. The results of this study were shown that the high accuracy of proposed model compared with fuzzy inference system. Also based on proposed model can be more accurately the rate of runoff estimated for future conditions.

  7. Drivers of increased organic carbon concentrations in stream water following forest disturbance: Separating effects of changes in flow pathways and soil warming

    Science.gov (United States)

    Schelker, J.; Grabs, T.; Bishop, K.; Laudon, H.

    2013-12-01

    disturbance such as clear-cutting has been identified as an important factor for increasing dissolved organic carbon (DOC) concentrations in boreal streams. We used a long-term data set of soil temperature, soil moisture, shallow groundwater (GW) levels, and stream DOC concentrations from three boreal first-order streams to investigate mechanisms causing these increases. Clear-cutting was found to alter soil conditions with warmer and wetter soils during summer. The application of a riparian flow concentration integration model (RIM) explained a major part of variation in stream [DOC] arising from changing flow pathways in riparian soils during the pretreatment period (r2 = 0.4-0.7), but less well after the harvest. Model residuals were sensitive to changes in soil temperature. The linear regression models for the temperature dependence of [DOC] in soils were not different in the disturbed and undisturbed catchments, whereas a nonlinear response to soil moisture was found. Overall these results suggest that the increased DOC mobilization after forest disturbance is caused by (i) increased GW levels leading to increased water fluxes in shallow flow path in riparian soils and (ii) increased soil temperature increasing the DOC availability in soils during summer. These relationships indicate that the mechanisms of DOC mobilization after forest disturbance are not different to those of undisturbed catchments, but that catchment soils respond to the higher hydro-climatic variation observed after clear-cutting. This highlights the sensitivity of boreal streams to changes in the energy and water balance, which may be altered as a result of both land management and climate change.

  8. Methods for estimating peak-flow frequencies at ungaged sites in Montana based on data through water year 2011: Chapter F in Montana StreamStats

    Science.gov (United States)

    Sando, Roy; Sando, Steven K.; McCarthy, Peter M.; Dutton, DeAnn M.

    2016-04-05

    The U.S. Geological Survey (USGS), in cooperation with the Montana Department of Natural Resources and Conservation, completed a study to update methods for estimating peak-flow frequencies at ungaged sites in Montana based on peak-flow data at streamflow-gaging stations through water year 2011. The methods allow estimation of peak-flow frequencies (that is, peak-flow magnitudes, in cubic feet per second, associated with annual exceedance probabilities of 66.7, 50, 42.9, 20, 10, 4, 2, 1, 0.5, and 0.2 percent) at ungaged sites. The annual exceedance probabilities correspond to 1.5-, 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively.Regional regression analysis is a primary focus of Chapter F of this Scientific Investigations Report, and regression equations for estimating peak-flow frequencies at ungaged sites in eight hydrologic regions in Montana are presented. The regression equations are based on analysis of peak-flow frequencies and basin characteristics at 537 streamflow-gaging stations in or near Montana and were developed using generalized least squares regression or weighted least squares regression.All of the data used in calculating basin characteristics that were included as explanatory variables in the regression equations were developed for and are available through the USGS StreamStats application (http://water.usgs.gov/osw/streamstats/) for Montana. StreamStats is a Web-based geographic information system application that was created by the USGS to provide users with access to an assortment of analytical tools that are useful for water-resource planning and management. The primary purpose of the Montana StreamStats application is to provide estimates of basin characteristics and streamflow characteristics for user-selected ungaged sites on Montana streams. The regional regression equations presented in this report chapter can be conveniently solved using the Montana StreamStats application.Selected results from

  9. Steady flow in a porous layer subjected to a stream uniformly injecting from a plane; Ichiyo ni men kara fukidasu nagare ni sarasareta takoshitsu sonai no teijo nagare

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, E; Horiguchi, Y; Kitazawa, K [Keio University, Tokyo (Japan). Faculty of Science and Technology

    1997-08-25

    A steady flow in an non-deformable porous layer subjected to a fluid stream is studied analytically and numerically. One side of the layer of sponge is bounded by a solid wall and the other by a layer of fluid. The fluid is injected uniformly from a plane, through which the fluid can pass, set up parallel to the sponge layer. The flow in the sponge layer is assumed to be governed by Darcy`s law. The problem considered is solved in terms of a similarity solution. The equations governing the fluid flows in both the porous layer and the fluid layer are reduced to a system of the ordinary differential equations. These equations are solved analytically for three cases ideal fluid flow, low Reynolds number flow and high Reynolds number flow. On the other hand, these equations are solved numerically for the general case by using the finite difference method. The distributions of the velocity and the pressure in both layers are found for various parameters. In particular, the speed which the fluid intrudes into the sponge layer due to the injection of the stream from the plane is found to be a function of dimensionless parameters. To find this speed is essential to the understanding of porous material. 15 refs., 9 figs.

  10. Surface-water quantity and quality, aquatic biology, stream geomorphology, and groundwater-flow simulation for National Guard Training Center at Fort Indiantown Gap, Pennsylvania, 2002-05

    Science.gov (United States)

    Langland, Michael J.; Cinotto, Peter J.; Chichester, Douglas C.; Bilger, Michael D.; Brightbill, Robin A.

    2010-01-01

    Base-line and long-term monitoring of water resources of the National Guard Training Center at Fort Indiantown Gap in south-central Pennsylvania began in 2002. Results of continuous monitoring of streamflow and turbidity and monthly and stormflow water-quality samples from two continuous-record long-term stream sites, periodic collection of water-quality samples from five miscellaneous stream sites, and annual collection of biological data from 2002 to 2005 at 27 sites are discussed. In addition, results from a stream-geomorphic analysis and classification and a regional groundwater-flow model are included. Streamflow at the facility was above normal for the 2003 through 2005 water years and extremely high-flow events occurred in 2003 and in 2004. Water-quality samples were analyzed for nutrients, sediments, metals, major ions, pesticides, volatile and semi-volatile organic compounds, and explosives. Results indicated no exceedances for any constituent (except iron) above the primary and secondary drinking-water standards or health-advisory levels set by the U.S. Environmental Protection Agency. Iron concentrations were naturally elevated in the groundwater within the watershed because of bedrock lithology. The majority of the constituents were at or below the method detection limit. Sediment loads were dominated by precipitation due to the remnants of Hurricane Ivan in September 2004. More than 60 percent of the sediment load measured during the entire study was transported past the streamgage in just 2 days during that event. Habitat and aquatic-invertebrate data were collected in the summers of 2002-05, and fish data were collected in 2004. Although 2002 was a drought year, 2003-05 were above-normal flow years. Results indicated a wide diversity in invertebrates, good numbers of taxa (distinct organisms), and on the basis of a combination of metrics, the majority of the 27 sites indicated no or slight impairment. Fish-metric data from 25 sites indicated results

  11. Sound stream segregation: a neuromorphic approach to solve the “cocktail party problem” in real-time

    Science.gov (United States)

    Thakur, Chetan Singh; Wang, Runchun M.; Afshar, Saeed; Hamilton, Tara J.; Tapson, Jonathan C.; Shamma, Shihab A.; van Schaik, André

    2015-01-01

    The human auditory system has the ability to segregate complex auditory scenes into a foreground component and a background, allowing us to listen to specific speech sounds from a mixture of sounds. Selective attention plays a crucial role in this process, colloquially known as the “cocktail party effect.” It has not been possible to build a machine that can emulate this human ability in real-time. Here, we have developed a framework for the implementation of a neuromorphic sound segregation algorithm in a Field Programmable Gate Array (FPGA). This algorithm is based on the principles of temporal coherence and uses an attention signal to separate a target sound stream from background noise. Temporal coherence implies that auditory features belonging to the same sound source are coherently modulated and evoke highly correlated neural response patterns. The basis for this form of sound segregation is that responses from pairs of channels that are strongly positively correlated belong to the same stream, while channels that are uncorrelated or anti-correlated belong to different streams. In our framework, we have used a neuromorphic cochlea as a frontend sound analyser to extract spatial information of the sound input, which then passes through band pass filters that extract the sound envelope at various modulation rates. Further stages include feature extraction and mask generation, which is finally used to reconstruct the targeted sound. Using sample tonal and speech mixtures, we show that our FPGA architecture is able to segregate sound sources in real-time. The accuracy of segregation is indicated by the high signal-to-noise ratio (SNR) of the segregated stream (90, 77, and 55 dB for simple tone, complex tone, and speech, respectively) as compared to the SNR of the mixture waveform (0 dB). This system may be easily extended for the segregation of complex speech signals, and may thus find various applications in electronic devices such as for sound segregation

  12. Sound stream segregation: a neuromorphic approach to solve the ‘cocktail party problem’ in real-time

    Directory of Open Access Journals (Sweden)

    Chetan Singh Thakur

    2015-09-01

    Full Text Available The human auditory system has the ability to segregate complex auditory scenes into a foreground component and a background, allowing us to listen to specific speech sounds from a mixture of sounds. Selective attention plays a crucial role in this process, colloquially known as the ‘cocktail party effect’. It has not been possible to build a machine that can emulate this human ability in real-time. Here, we have developed a framework for the implementation of a neuromorphic sound segregation algorithm in a Field Programmable Gate Array (FPGA. This algorithm is based on the principles of temporal coherence and uses an attention signal to separate a target sound stream from background noise. Temporal coherence implies that auditory features belonging to the same sound source are coherently modulated and evoke highly correlated neural response patterns. The basis for this form of sound segregation is that responses from pairs of channels that are strongly positively correlated belong to the same stream, while channels that are uncorrelated or anti-correlated belong to different streams. In our framework, we have used a neuromorphic cochlea as a frontend sound analyser to extract spatial information of the sound input, which then passes through band pass filters that extract the sound envelope at various modulation rates. Further stages include feature extraction and mask generation, which is finally used to reconstruct the targeted sound. Using sample tonal and speech mixtures, we show that our FPGA architecture is able to segregate sound sources in real-time. The accuracy of segregation is indicated by the high signal-to-noise ratio (SNR of the segregated stream (90, 77 and 55 dB for simple tone, complex tone and speech, respectively as compared to the SNR of the mixture waveform (0 dB. This system may be easily extended for the segregation of complex speech signals, and may thus find various applications in electronic devices such as for

  13. A time-dependent Green's function-based model for stream ...

    African Journals Online (AJOL)

    DRINIE

    2003-07-03

    Jul 3, 2003 ... applications, this Green's function has found use primarily in linear heat transfer and flow ... based on the mathematical description of the flow with the nonlinear .... i∂/∂x + j∂/∂y is the two-dimensional gradient operator,.

  14. New methods for modeling stream temperature using high resolution LiDAR, solar radiation analysis and flow accumulated values

    Science.gov (United States)

    In-stream temperature directly effects a variety of biotic organisms, communities and processes. Changes in stream temperature can render formally suitable habitat unsuitable for aquatic organisms, particularly native cold water species that are not able to adjust. In order to an...

  15. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Base Flow Index

    Science.gov (United States)

    This dataset represents the base flow index values within individual, local NHDPlusV2 catchments and upstream, contributing watersheds. Attributes of the landscape layer were calculated for every local NHDPlusV2 catchment and accumulated to provide watershed-level metrics. (See Supplementary Info for Glossary of Terms) The base-flow index (BFI) grid for the conterminous United States was developed to estimate (1) BFI values for ungaged streams, and (2) ground-water recharge throughout the conterminous United States (see Source_Information). Estimates of BFI values at ungaged streams and BFI-based ground-water recharge estimates are useful for interpreting relations between land use and water quality in surface and ground water. The bfi (%) was summarized by local catchment and by watershed to produce local catchment-level and watershed-level metrics as a continuous data type (see Data Structure and Attribute Information for a description).

  16. Real-time video streaming system for LHD experiment using IP multicast

    International Nuclear Information System (INIS)

    Emoto, Masahiko; Yamamoto, Takashi; Yoshida, Masanobu; Nagayama, Yoshio; Hasegawa, Makoto

    2009-01-01

    In order to accomplish smooth cooperation research, remote participation plays an important role. For this purpose, the authors have been developing various applications for remote participation for the LHD (Large Helical Device) experiments, such as Web interface for visualization of acquired data. The video streaming system is one of them. It is useful to grasp the status of the ongoing experiment remotely, and we provide the video images displayed in the control room to the remote users. However, usual streaming servers cannot send video images without delay. The delay changes depending on how to send the images, but even a little delay might become critical if the researchers use the images to adjust the diagnostic devices. One of the main causes of delay is the procedure of compressing and decompressing the images. Furthermore, commonly used video compression method is lossy; it removes less important information to reduce the size. However, lossy images cannot be used for physical analysis because the original information is lost. Therefore, video images for remote participation should be sent without compression in order to minimize the delay and to supply high quality images durable for physical analysis. However, sending uncompressed video images requires large network bandwidth. For example, sending 5 frames of 16bit color SXGA images a second requires 100Mbps. Furthermore, the video images must be sent to several remote sites simultaneously. It is hard for a server PC to handle such a large data. To cope with this problem, the authors adopted IP multicast to send video images to several remote sites at once. Because IP multicast packets are sent only to the network on which the clients want the data; the load of the server does not depend on the number of clients and the network load is reduced. In this paper, the authors discuss the feasibility of high bandwidth video streaming system using IP multicast. (author)

  17. Real-time detection and classification of anomalous events in streaming data

    Science.gov (United States)

    Ferragut, Erik M.; Goodall, John R.; Iannacone, Michael D.; Laska, Jason A.; Harrison, Lane T.

    2016-04-19

    A system is described for receiving a stream of events and scoring the events based on anomalousness and maliciousness (or other classification). The events can be displayed to a user in user-defined groupings in an animated fashion. The system can include a plurality of anomaly detectors that together implement an algorithm to identify low probability events and detect atypical traffic patterns. The atypical traffic patterns can then be classified as being of interest or not. In one particular example, in a network environment, the classification can be whether the network traffic is malicious or not.

  18. Multi-relaxation-time Lattice Boltzman model for uniform-shear flow over a rotating circular cylinder

    Directory of Open Access Journals (Sweden)

    Nemati Hasan

    2011-01-01

    Full Text Available A numerical investigation of the two-dimensional laminar flow and heat transfer a rotating circular cylinder with uniform planar shear, where the free-stream velocity varies linearly across the cylinder using Multi-Relaxation-Time Lattice Boltzmann method is conducted. The effects of variation of Reynolds number, rotational speed ratio at shear rate 0.1, blockage ratio 0.1 and Prandtl number 0.71 are studied. The Reynolds number changing from 50 to 160 for three rotational speed ratios of 0, 0.5, 1 is investigated. Results show that flow and heat transfer depends significantly on the rotational speed ratio as well as the Reynolds number. The effect of Reynolds number on the vortex-shedding frequency and period-surface Nusselt numbers is overall very strong compared with rotational speed ratio. Flow and heat conditions characteristics such as lift and drag coefficients, Strouhal number and Nusselt numbers are studied.

  19. Streaming reversal of energetic particles in the magnetotail during a substorm

    Science.gov (United States)

    Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.; Akasofu, S.-I.

    1984-01-01

    A case of reversal in the streaming anisotropy of energetic ions and in the plasma flow observed from the IMP 8 spacecraft during a substorm on February 8, 1978 is studied in detail using measurements of energetic particles, plasma, and magnetic field. Four new features emerge when high time resolution data are examined in detail. The times of streaming reversal of energetic particles in different energy ranges do not coincide with the time of plasma flow reversal. Qualitatively different velocity distributions are observed in earthward and tailward plasma flows during the observed flow reversal intervals. Strong tailward streaming of energetic particles can be detected during northward magnetic field environments and, conversely, earthward streaming in southward field environments. During the period of tailward streaming of energetic particles, earthward streaming fluxes are occasionally detected.

  20. Intercomparison of principal hydrometric instruments; Third phase, Evaluation of ultrasonic velocity meters for flow measurement in streams, canals, and estuaries

    Science.gov (United States)

    Melching, Charles S.; Meno, Michael W.

    1998-01-01

    As part of the World Meteorological Organization (WMO) project Intercomparison of Principal Hydrometric Instruments, Third Phase, a questionnaire was prepared by the U.S. Geological Survey (USGS) on the application of Ultrasonic Velocity Meters (UVM's) for flowmeasurement in streams, canals, and estuaries. In 1996, this questionnaire was distributed internationally by the WMO and USGS, and distributed within the United States by the USGS. Completed questionnaires were returned by 26 agencies in 7 countries (Canada, France, Germany, The Netherlands, Switzerland, the United Kingdom, and the United States). The completed questionnaires described geometric and streamflow conditions, system configurations, and reasons for applying UVM systems for 260 sites, thus providing information on the applicability of UVM systems throughout the world. The completed questionnaires also provided information on operational issues such as (1) methods used to determine and verify UVM ratings, (2) methods used to determine the mean flow velocity for UVM systems, (3) operational reliability of UVM systems, (4) methods to estimate missing data, (5) common problems with UVM systems and guidelines to mitigate these problems, and (6) personnel training issues. The completed questionnaires also described a few unique or novel applications of UVM systems. In addition to summarizing the completed questionnaires, this report includes a brief overview of UVM application and operation, and a short summary of current (1998) information from UVM system manufacturers regarding system cost and capabilities. On the basis of the information from the completed questionnaires and provided by the manufacturers, the general applicability of UVM systems is discussed. In the finalisation of this report the financial support provided by the US National Committee for Scientific Hydrology is gratefully acknowledged.

  1. Sediment Mobilization and Storage Dynamics of a Debris Flow Impacted Stream Channel using Multi-Temporal Structure from Motion Photogrammetry

    Science.gov (United States)

    Bailey, T. L.; Sutherland-Montoya, D.

    2015-12-01

    High resolution topographic analysis methods have become important tools in geomorphology. Structure from Motion photogrammetry offers a compelling vehicle for geomorphic change detection in fluvial environments. This process can produce arbitrarily high resolution, geographically registered spectral and topographic coverages from a collection of overlapping digital imagery from consumer cameras. Cuneo Creek has had three historically observed episodes of rapid aggradation (1955, 1964, and 1997). The debris flow deposits continue to be major sources of sediment sixty years after the initial slope failure. Previous studies have monitored the sediment storage volume and particle size since 1976 (in 1976, 1982, 1983, 1985, 1986, 1987, 1998, 2003). We reoccupied 3 previously surveyed stream cross sections on Sept 30, 2014 and March 30, 2015, and produced photogrammetric point clouds using a pole mounted camera with a remote view finder to take nadir view images from 4.3 meters above the channel bed. Ground control points were registered using survey grade GPS and typical cross sections used over 100 images to build the structure model. This process simultaneously collects channel geometry and we used it to also generate surface texture metrics, and produced DEMs with point cloud densities above 5000 points / m2. In the period between the surveys, a five year recurrence interval discharge of 20 m3/s scoured the channel. Surface particle size distribution has been determined for each observation period using image segmentation algorithms based on spectral distance and compactness. Topographic differencing between the point clouds shows substantial channel bed mobilization and reorganization. The net decline in sediment storage is in excess of 4 x 10^5 cubic meters since the 1964 aggradation peak, with associated coarsening of surface particle sizes. These new methods provide a promising rapid assessment tool for measurement of channel responses to sediment inputs.

  2. Medical education in India: Time to encourage cross-talk between different streams

    Directory of Open Access Journals (Sweden)

    Kishor Patwardhan

    2013-01-01

    Full Text Available Currently, India recognizes five different healthcare systems, collectively known as AYUSH (Ayurveda, Yoga, Unani, Siddha, Homeopathy, along with the conventional biomedicine. These systems have their own institutionalized structure for monitoring medical education and practice. However, because of the ′parallel′ kind of policy model that is followed in India, there is no formal provision for any cross-talk between the professionals belonging to these different streams. This situation has not only given rise to mutual misgivings among these professionals regarding the strengths and weaknesses of each other, but also has led to a poor appreciation of the historical and socio-cultural connections these streams share with the community at large. To tackle these issues and to promote adequate participation of biomedicine experts in AYUSH-related research projects, ′introduction of an AYUSH module in the current curriculum of MBBS (Bachelor of Medicine and Bachelor of Surgery program′ has been proposed in this communication along with a possible roadmap for its implementation. It is also suggested that the experts in biomedicine be engaged for training AYUSH graduates in their respective specialties so that quality AYUSH education may be ensured.

  3. A time-varying subjective quality model for mobile streaming videos with stalling events

    Science.gov (United States)

    Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C.

    2015-09-01

    Over-the-top mobile video streaming is invariably influenced by volatile network conditions which cause playback interruptions (stalling events), thereby impairing users' quality of experience (QoE). Developing models that can accurately predict users' QoE could enable the more efficient design of quality-control protocols for video streaming networks that reduce network operational costs while still delivering high-quality video content to the customers. Existing objective models that predict QoE are based on global video features, such as the number of stall events and their lengths, and are trained and validated on a small pool of ad hoc video datasets, most of which are not publicly available. The model we propose in this work goes beyond previous models as it also accounts for the fundamental effect that a viewer's recent level of satisfaction or dissatisfaction has on their overall viewing experience. In other words, the proposed model accounts for and adapts to the recency, or hysteresis effect caused by a stall event in addition to accounting for the lengths, frequency of occurrence, and the positions of stall events - factors that interact in a complex way to affect a user's QoE. On the recently introduced LIVE-Avvasi Mobile Video Database, which consists of 180 distorted videos of varied content that are afflicted solely with over 25 unique realistic stalling events, we trained and validated our model to accurately predict the QoE, attaining standout QoE prediction performance.

  4. Efficient Hardware Implementation of the Horn-Schunck Algorithm for High-Resolution Real-Time Dense Optical Flow Sensor

    Science.gov (United States)

    Komorkiewicz, Mateusz; Kryjak, Tomasz; Gorgon, Marek

    2014-01-01

    This article presents an efficient hardware implementation of the Horn-Schunck algorithm that can be used in an embedded optical flow sensor. An architecture is proposed, that realises the iterative Horn-Schunck algorithm in a pipelined manner. This modification allows to achieve data throughput of 175 MPixels/s and makes processing of Full HD video stream (1, 920 × 1, 080 @ 60 fps) possible. The structure of the optical flow module as well as pre- and post-filtering blocks and a flow reliability computation unit is described in details. Three versions of optical flow modules, with different numerical precision, working frequency and obtained results accuracy are proposed. The errors caused by switching from floating- to fixed-point computations are also evaluated. The described architecture was tested on popular sequences from an optical flow dataset of the Middlebury University. It achieves state-of-the-art results among hardware implementations of single scale methods. The designed fixed-point architecture achieves performance of 418 GOPS with power efficiency of 34 GOPS/W. The proposed floating-point module achieves 103 GFLOPS, with power efficiency of 24 GFLOPS/W. Moreover, a 100 times speedup compared to a modern CPU with SIMD support is reported. A complete, working vision system realized on Xilinx VC707 evaluation board is also presented. It is able to compute optical flow for Full HD video stream received from an HDMI camera in real-time. The obtained results prove that FPGA devices are an ideal platform for embedded vision systems. PMID:24526303

  5. Using travel times to simulate multi-dimensional bioreactive transport in time-periodic flows.

    Science.gov (United States)

    Sanz-Prat, Alicia; Lu, Chuanhe; Finkel, Michael; Cirpka, Olaf A

    2016-04-01

    In travel-time models, the spatially explicit description of reactive transport is replaced by associating reactive-species concentrations with the travel time or groundwater age at all locations. These models have been shown adequate for reactive transport in river-bank filtration under steady-state flow conditions. Dynamic hydrological conditions, however, can lead to fluctuations of infiltration velocities, putting the validity of travel-time models into question. In transient flow, the local travel-time distributions change with time. We show that a modified version of travel-time based reactive transport models is valid if only the magnitude of the velocity fluctuates, whereas its spatial orientation remains constant. We simulate nonlinear, one-dimensional, bioreactive transport involving oxygen, nitrate, dissolved organic carbon, aerobic and denitrifying bacteria, considering periodic fluctuations of velocity. These fluctuations make the bioreactive system pulsate: The aerobic zone decreases at times of low velocity and increases at those of high velocity. For the case of diurnal fluctuations, the biomass concentrations cannot follow the hydrological fluctuations and a transition zone containing both aerobic and obligatory denitrifying bacteria is established, whereas a clear separation of the two types of bacteria prevails in the case of seasonal velocity fluctuations. We map the 1-D results to a heterogeneous, two-dimensional domain by means of the mean groundwater age for steady-state flow in both domains. The mapped results are compared to simulation results of spatially explicit, two-dimensional, advective-dispersive-bioreactive transport subject to the same relative fluctuations of velocity as in the one-dimensional model. The agreement between the mapped 1-D and the explicit 2-D results is excellent. We conclude that travel-time models of nonlinear bioreactive transport are adequate in systems of time-periodic flow if the flow direction does not change

  6. Fusion of product and process data: Batch-mode and real-time streaming

    Energy Technology Data Exchange (ETDEWEB)

    Vincent De Sapio; Spike Leonard

    1999-12-01

    In today's DP product realization enterprise it is imperative to reduce the design-to-fabrication cycle time and cost while improving the quality of DP parts (reducing defects). Much of this challenge resides in the inherent gap between the product and process worlds. The lack of seamless, bi-directional flow of information prevents true concurrency in the product realization world. This report addresses a framework for product-process data fusion to help achieve next generation product realization. A fundamental objective is to create an open environment for multichannel observation of process date, and subsequent mapping of that data onto product geometry. In addition to the sensor-based observation of manufacturing processes, model-based process data provides an important complement to empirically acquired data. Two basic groups of manufacturing models are process physics, and machine kinematics and dynamics. Process physics addresses analytical models that describe the physical phenomena of the process itself. Machine kinematic and dynamic models address the mechanical behavior of the processing equipment. As a secondary objective, an attempt has been made in this report to address part of the model-based realm through the development of an open object-oriented library and toolkit for machine kinematics and dynamics. Ultimately, it is desirable to integrate design definition, with all types of process data; both sensor-based and model-based. Collectively, the goal is to allow all disciplines within the product realization enterprise to have a centralized medium for the fusion of product and process data.

  7. DASHBOARD.awi.de: Streaming and monitoring solutions for near real-time data

    OpenAIRE

    Koppe, Roland; Gerchow, Peter; Macario, Ana; Haas, Antonie; Schäfer-Neth, Christian; Rehmcke, Steven; Walter, Andreas; Düde, Tobias; Weidinger, Philipp; Schäfer, Angela; Pfeiffenberger, Hans

    2018-01-01

    DASHBOARD.awi.de is a component of our data flow framework designed to enable a semi-automated flow of sensor observations to archives (acronym O2A). The dramatic increase in the number and type of platforms and respective sensors operated by Alfred Wegener Institute along with complex project-driven requirements in terms of satellite communication, sensor monitoring, quality control and validation, processing pipelines, visualization, and archival under FAIR principles, led us to build a...

  8. Behavioural and physiological responses of brook trout Salvelinus fontinalis to midwinter flow reduction in a small ice-free mountain stream.

    Science.gov (United States)

    Krimmer, A N; Paul, A J; Hontela, A; Rasmussen, J B

    2011-09-01

    This study presents an experimental analysis of the effects of midwinter flow reduction (50-75%, reduction in discharge in 4 h daily pulses) on the physical habitat and on behaviour and physiology of overwintering brook trout Salvelinus fontinalis in a small mountain stream. Flow reduction did not result in significant lowering of temperature or formation of surface or subsurface ice. The main findings were (1) daily movement by S. fontinalis increased (c. 2·5-fold) during flow reduction, but was limited to small-scale relocations (reduced during flow reduction. (3) Although both experimental and reference fish did lose mass and condition during the experiment, no effects of flow reduction on stress indicators (blood cortisol or glucose) or bioenergetics (total body fat, water content or mass loss) were detected, probably because access to the preferred type of cover remained available. Like other salmonids, S. fontinalis moves little and seeks physical cover during winter. Unlike many of the more studied salmonids, however, this species overwinters successfully in small groundwater-rich streams that often remain ice-free, and this study identifies undercut banks as the critical winter habitat rather than substratum cover. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  9. Real time high frequency monitoring of water quality in river streams using a UV-visible spectrometer: interest, limits and consequences for monitoring strategies

    Science.gov (United States)

    Faucheux, Mikaël; Fovet, Ophélie; Gruau, Gérard; Jaffrézic, Anne; Petitjean, Patrice; Gascuel-Odoux, Chantal; Ruiz, Laurent

    2013-04-01

    Stream water chemistry is highly variable in space and time, therefore high frequency water quality measurement methods are likely to lead to conceptual advances in the hydrological sciences. Sub-daily data on water quality improve the characterization of pollutant sources and pathways during flood events as well as during long-term periods [1]. However, real time, high frequency monitoring devices needs to be properly calibrated and validated in real streams. This study analyses data from in situ monitoring of a stream water quality. During two hydrological years (2010-11, 2011-12), a submersible UV-visible spectrometer (Scan Spectrolyser) was used for surface water quality measurement at the outlet of a headwater catchment located at Kervidy-Naizin, Western France (AgrHys long-term hydrological observatory, http://www.inra.fr/ore_agrhys/). The spectrometer is reagentless and equipped with an auto-cleaning system. It allows real time, in situ and high frequency (20 min) measurements and uses a multiwavelengt spectral (200-750 nm) for simultaneous measurement of nitrate, dissolved organic carbon (DOC) and total suspended solids (TSS). A global calibration based on a PLS (Partial Least Squares) regression is provided by the manufacturer as default configuration of the UV-visible spectrometer. We carried out a local calibration of the spectrometer based on nitrates and DOC concentrations analysed in the laboratory from daily manual sampling and sub-daily automatic sampling of flood events. TSS results are compared with 15 min turbidity records from a continuous turdidimeter (Ponsel). The results show a good correlation between laboratory data and spectrometer data both during basis flows periods and flood events. However, the local calibration gives better results than the global one. Nutrient fluxes estimates based on high and different low frequency time series (daily to monthly) are compared to discuss the implication for environmental monitoring strategies. Such

  10. Non-clairvoyant weighted flow time scheduling with rejection penalty

    DEFF Research Database (Denmark)

    Chan, Ho-Leung; Chan, Sze-Hang; Lam, Tak-Wah

    2012-01-01

    is defined as the weighted flow time of the job plus the penalty if it is rejected before completion. Previous work on minimizing the total user cost focused on the clairvoyant single-processor setting [BBC+03,CLL11] and has produced O(1)-competitive online algorithm for jobs with arbitrary weights...... algorithm has to decide job rejection and determine the order and speed of job execution. It is interesting to study the tradeoff between the above-mentioned user cost and energy. This paper gives two O(1)-competitive non-clairvoyant algorithms for minimizing the user cost plus energy on a single processor......This paper initiates the study of online scheduling with rejection penalty in the non-clairvoyant setting, i.e., the size (processing time) of a job is not assumed to be known at its release time. In the rejection penalty model, jobs can be rejected with a penalty, and the user cost of a job...

  11. Arrival-Time Detection and Ultrasonic Flow-Meter Applications

    International Nuclear Information System (INIS)

    Willatzen, Morten; Soendergaard, Peter; Latino, Carl; Voss, Frands; Andersen, Niels Lervad; Brokate, Martin; Bounaim, Aicha

    2006-01-01

    The Danfoss problem on ultrasonic flow measurement has been separated into three parts each handled by a subgroup of the authors listed above. The first subgroup deals with a presentation of modelling equations describing the physics of ultrasonic flow meters employing reciprocal ultrasonic transducer systems. The mathematical model presented allows the electrical output signal to be determined corresponding to any time-dependent electrical input signal. The transducers modelled consist of a piezoceramic material layer and a passive acoustic matching layer. The second subgroup analyzes the possibility of coding the input signal so as to simplify arrival-time detection by re.nding the coded input sequence in the received signal. The narrow-band nature of the transducers makes this problem non-trivial but suggestions for improvement are proposed. The analysis given is based on traditional autoand cross-correlation techniques. The third subgroup attempts to improve existing correlation methods in determining arrival-time detection of signals. A mathematical formulation of the problem is given and the application to a set of real signals provided by Danfoss A/S is performed with good results

  12. Task-oriented quality assessment and adaptation in real-time mission critical video streaming applications

    Science.gov (United States)

    Nightingale, James; Wang, Qi; Grecos, Christos

    2015-02-01

    In recent years video traffic has become the dominant application on the Internet with global year-on-year increases in video-oriented consumer services. Driven by improved bandwidth in both mobile and fixed networks, steadily reducing hardware costs and the development of new technologies, many existing and new classes of commercial and industrial video applications are now being upgraded or emerging. Some of the use cases for these applications include areas such as public and private security monitoring for loss prevention or intruder detection, industrial process monitoring and critical infrastructure monitoring. The use of video is becoming commonplace in defence, security, commercial, industrial, educational and health contexts. Towards optimal performances, the design or optimisation in each of these applications should be context aware and task oriented with the characteristics of the video stream (frame rate, spatial resolution, bandwidth etc.) chosen to match the use case requirements. For example, in the security domain, a task-oriented consideration may be that higher resolution video would be required to identify an intruder than to simply detect his presence. Whilst in the same case, contextual factors such as the requirement to transmit over a resource-limited wireless link, may impose constraints on the selection of optimum task-oriented parameters. This paper presents a novel, conceptually simple and easily implemented method of assessing video quality relative to its suitability for a particular task and dynamically adapting videos streams during transmission to ensure that the task can be successfully completed. Firstly we defined two principle classes of tasks: recognition tasks and event detection tasks. These task classes are further subdivided into a set of task-related profiles, each of which is associated with a set of taskoriented attributes (minimum spatial resolution, minimum frame rate etc.). For example, in the detection class

  13. Analysis of hydraulic characteristics for stream diversion in small stream

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sang-Jin; Jun, Kye-Won [Chungbuk National University, Cheongju(Korea)

    2001-10-31

    This study is the analysis of hydraulic characteristics for stream diversion reach by numerical model test. Through it we can provide the basis data in flood, and in grasping stream flow characteristics. Analysis of hydraulic characteristics in Seoknam stream were implemented by using computer model HEC-RAS(one-dimensional model) and RMA2(two-dimensional finite element model). As a result we became to know that RMA2 to simulate left, main channel, right in stream is more effective method in analysing flow in channel bends, steep slope, complex bed form effect stream flow characteristics, than HEC-RAS. (author). 13 refs., 3 tabs., 5 figs.

  14. The concept of value stream mapping to reduce of work-time waste as applied the smart construction management

    Science.gov (United States)

    Elizar, Suripin, Wibowo, Mochamad Agung

    2017-11-01

    Delays in construction sites occur due to systematic additions of time waste in various activities that are part of the construction process. Work-time waste is non-adding value activity which used to differentiate between physical construction waste found on site and other waste which occurs during the construction process. The aim of this study is identification using the concept of Value Stream Mapping (VSM) to reduce of work-time waste as applied the smart construction management.VSM analysis is a method of business process improvement. The application of VSM began in the manufacturing community. The research method base on theoretically informed case study and literature review. The data have collected using questionnaire through personal interviews from 383 respondents on construction project in Indonesia. The results show that concept of VSM can identify causes of work-time waste. Base on result of questioners and quantitative approach analysis was obtained 29 variables that influence of work-time waste or non-value-adding activities. Base on three cases of construction project founded that average 14.88% of working time was classified as waste. Finally, the concept of VSM can recommend to identification of systematic for reveal current practices and opportunities for improvement towards global challenges. The concept of value stream mapping can help optimize to reduce work-time waste and improve quality standard of construction management. The concept is also can help manager to make a decision to reduce work-time waste so as to obtain of result in more efficient for performance and sustainable construction project.

  15. Studi Implementasi Lean Six Sigma dengan Pendekatan Value Stream Mapping untuk Mereduksi Idle Time Material pada Gudang Pelat dan Profil

    Directory of Open Access Journals (Sweden)

    Wawan Widiatmoko

    2013-03-01

    Full Text Available Peningkatan volume kegiatan industri maritim di Indonesia menuntut industri perkapalan di daerah Surabaya untuk lebih meningkatkan pelayanan baik berupa bangunan baru maupun reparasi kapal. Berdasarkan hal tersebut galangan harus mampu mengelola proses produksi dengan baik sehingga menghasilkan keuntungan yang maksimum. Salah satunya adalah proses inventory dan transport of materials yang efektif. Tugas akhir bertujuan untuk mengetahui sistem inventori yang diterapkan oleh perusahaan yang dijadikan sampel serta idle time material pelat dan profil yang ada di gudang bahan baku dengan menggunakan metode lean six sigma dengan pendekatan value stream mapping. Dari hasil perhitungan menggunakan diperoleh nilai sigma perhitungan idle time sebesar 0.1976 sehingga perlu dilakukan upaya peningkatan nilai sigma pengadaan material itu sendiri. Berdasarkan hasil analisa penyebab adanya idle time dengan menggunakan RCA diperoleh beberapa faktor yaitu : rendahnya nilai sigma penggunaan material, tidak tercapainya target pengerjaan pada proses fabrikasi, proses pengadaan material yang tidak mempertimbangkan strategi proses pembangunan kapal. Dengan penerapan lean six sigma dengan pendekatan value stream mapping dihasilkan usulan perbaikan proses inventori di perusahaan antara lain : meningkatkan nilai sigma penggunaan material, melakukan strategi pembelian material sesuai strategi pembangunan kapal berdasarkan zona, memperbaiki kerjasama dengan supplier material pelat dan profil. Pembuatan future state mapping mendapatkan usulan perbaikan dengan pembuatan perencanaan pengadaan material dengan mempertimbangkan strategi pembangunan kapal berdasarkan zona pembangunannya. Diperoleh strategi pengadaan material yang dilakukan sebanyak 4 kali order.

  16. In-line near real time monitoring of fluid streams in separation processes for used nuclear fuel - 5146

    International Nuclear Information System (INIS)

    Nee, K.; Nilsson, M.

    2015-01-01

    Applying spectroscopic tools for chemical processes has been intensively studied in various industries owing to its rapid and non-destructive analysis for detecting chemical components and determine physical characteristic in a process stream. The general complexity of separation processes for used nuclear fuel, e.g., chemical speciation, temperature variations, and prominent process security and safety concerns, require a well-secured and robust monitoring system to provide precise information of the process streams at real time without interference. Multivariate analysis accompanied with spectral measurements is a powerful statistic technique that can be used to monitor this complex chemical system. In this work, chemometric models that respond to the chemical components in the fluid samples were calibrated and validated to establish an in-line near real time monitoring system. The models show good prediction accuracy using partial least square regression analysis on the spectral data obtained from UV/Vis/NIR spectroscopies. The models were tested on a solvent extraction process using a single stage centrifugal contactor in our laboratory to determine the performance of an in-line near real time monitoring system. (authors)

  17. Estimation of low-flow statistics at ungaged sites on streams in the Lower Hudson River Basin, New York, from data in geographic information systems

    Science.gov (United States)

    Randall, Allan D.; Freehafer, Douglas A.

    2017-08-02

    A variety of watershed properties available in 2015 from geographic information systems were tested in regression equations to estimate two commonly used statistical indices of the low flow of streams, namely the lowest flows averaged over 7 consecutive days that have a 1 in 10 and a 1 in 2 chance of not being exceeded in any given year (7-day, 10-year and 7-day, 2-year low flows). The equations were based on streamflow measurements in 51 watersheds in the Lower Hudson River Basin of New York during the years 1958–1978, when the number of streamflow measurement sites on unregulated streams was substantially greater than in subsequent years. These low-flow indices are chiefly a function of the area of surficial sand and gravel in the watershed; more precisely, 7-day, 10-year and 7-day, 2-year low flows both increase in proportion to the area of sand and gravel deposited by glacial meltwater, whereas 7-day, 2-year low flows also increase in proportion to the area of postglacial alluvium. Both low-flow statistics are also functions of mean annual runoff (a measure of net water input to the watershed from precipitation) and area of swamps and poorly drained soils in or adjacent to surficial sand and gravel (where groundwater recharge is unlikely and riparian water loss to evapotranspiration is substantial). Small but significant refinements in estimation accuracy resulted from the inclusion of two indices of stream geometry, channel slope and length, in the regression equations. Most of the regression analysis was undertaken with the ordinary least squares method, but four equations were replicated by using weighted least squares to provide a more realistic appraisal of the precision of low-flow estimates. The most accurate estimation equations tested in this study explain nearly 84 and 87 percent of the variation in 7-day, 10-year and 7-day, 2-year low flows, respectively, with standard errors of 0.032 and 0.050 cubic feet per second per square mile. The equations

  18. Time complexity and linear-time approximation of the ancient two-machine flow shop

    NARCIS (Netherlands)

    Rote, G.; Woeginger, G.J.

    1998-01-01

    We consider the scheduling problems F2¿Cmax and F2|no-wait|Cmax, i.e. makespan minimization in a two-machine flow shop, with and without no wait in process. For both problems solution algorithms based on sorting with O(n log n) running time are known, where n denotes the number of jobs. [1, 2]. We

  19. Near Real-Time Call Detail Record ETL Flows

    Science.gov (United States)

    Cochinwala, Munir; Panagos, Euthimios

    Telecommunication companies face significant business challenges as they strive to reduce subscriber churn and increase average revenue per user (ARPU) by offering new services and incorporating new functionality into existing services. The increased number of service offerings and available functionality result in an ever growing volume of call detail records (CDRs). For many services (e.g., pre-paid), CDRs need to be processed and analyzed in near real-time for several reasons, including charging, on-line subscriber access to their accounts, and analytics for predicting subscriber usage and preventing fraudulent activity. In this paper, we describe the challenges associated with near real-time extract, transform, and load (ETL) of CDR data warehouse flows for supporting both the operational and business intelligence needs of telecommunication services, and we present our approach to addressing these challenges.

  20. Time-delayed feedback technique for suppressing instabilities in time-periodic flow

    Science.gov (United States)

    Shaabani-Ardali, Léopold; Sipp, Denis; Lesshafft, Lutz

    2017-11-01

    A numerical method is presented that allows to compute time-periodic flow states, even in the presence of hydrodynamic instabilities. The method is based on filtering nonharmonic components by way of delayed feedback control, as introduced by Pyragas [Phys. Lett. A 170, 421 (1992), 10.1016/0375-9601(92)90745-8]. Its use in flow problems is demonstrated here for the case of a periodically forced laminar jet, subject to a subharmonic instability that gives rise to vortex pairing. The optimal choice of the filter gain, which is a free parameter in the stabilization procedure, is investigated in the context of a low-dimensional model problem, and it is shown that this model predicts well the filter performance in the high-dimensional flow system. Vortex pairing in the jet is efficiently suppressed, so that the unstable periodic flow state in response to harmonic forcing is accurately retrieved. The procedure is straightforward to implement inside any standard flow solver. Memory requirements for the delayed feedback control can be significantly reduced by means of time interpolation between checkpoints. Finally, the method is extended for the treatment of periodic problems where the frequency is not known a priori. This procedure is demonstrated for a three-dimensional cubic lid-driven cavity in supercritical conditions.

  1. Stream Flow Prediction and Flood Mapping in the Hindu Kush-Himalaya with the ICIMOD Water Resources App Portal (IWRAP)

    Science.gov (United States)

    Nelson, J.; Ames, D. P.; Jones, N.; Souffront, M.

    2016-12-01

    Earth observations of precipitation, temperature, moisture, and other atmospheric and land surface conditions form the foundation of global hydrologic forecasts that are increasingly available in native as well as other derived products. The European Centre for Medium Range Weather Forecasts (ECMWF) have developed such products for global flood awareness which can be downscaled to smaller regions and used for stream flow prediction in underserved areas such as the Hindu Kush-Himalaya. Combined with digital elevation data, now available at 30 meters through the Shuttle Radar Topography Mission (SRTM) reconnaissance-level flood maps can be generated across wide regions that would otherwise not be possible and where increased information to drive higher resolution models are available the same forecasts can be used to provide forcing inflows for improved flood maps. Advances in cloud computing offer a unique opportunity to facilitate deployment of water resources models as decision-making tools in the cloud-based ICIMOD Water Resources App Portal or IWRAP. The interactive nature of web apps makes this an excellent medium for creating decision support tools that harness cutting edge modeling techniques. Thin client apps hosted in a cloud portal eliminates the need for the decision makers to procure and maintain the high performance hardware required by the models, deal with issues related to software installation and platform incompatibilities, or monitor and install software updates, a problem that is exacerbated in the Hindu Kush-Himalaya where both financial and technical capacity are limited. All that is needed to use the system is an Internet connection and a web browser. We will take advantage of these technologies to develop tools which can be centrally maintained but openly accessible. Advanced mapping and visualization will make results intuitive and information derived actionable. We will also take advantage of the emerging standards for sharing water

  2. Simulated groundwater flow paths, travel time, and advective transport of nitrogen in the Kirkwood-Cohansey aquifer system, Barnegat Bay–Little Egg Harbor Watershed, New Jersey

    Science.gov (United States)

    Voronin, Lois M.; Cauller, Stephen J.

    2017-07-31

    Elevated concentrations of nitrogen in groundwater that discharges to surface-water bodies can degrade surface-water quality and habitats in the New Jersey Coastal Plain. An analysis of groundwater flow in the Kirkwood-Cohansey aquifer system and deeper confined aquifers that underlie the Barnegat Bay–Little Egg Harbor (BB-LEH) watershed and estuary was conducted by using groundwater-flow simulation, in conjunction with a particle-tracking routine, to provide estimates of groundwater flow paths and travel times to streams and the BB-LEH estuary.Water-quality data from the Ambient Groundwater Quality Monitoring Network, a long-term monitoring network of wells distributed throughout New Jersey, were used to estimate the initial nitrogen concentration in recharge for five different land-use classes—agricultural cropland or pasture, agricultural orchard or vineyard, urban non-residential, urban residential, and undeveloped. Land use at the point of recharge within the watershed was determined using a geographic information system (GIS). Flow path starting locations were plotted on land-use maps for 1930, 1973, 1986, 1997, and 2002. Information on the land use at the time and location of recharge, time of travel to the discharge location, and the point of discharge were determined for each simulated flow path. Particle-tracking analysis provided the link from the point of recharge, along the particle flow path, to the point of discharge, and the particle travel time. The travel time of each simulated particle established the recharge year. Land use during the year of recharge was used to define the nitrogen concentration associated with each flow path. The recharge-weighted average nitrogen concentration for all flow paths that discharge to the Toms River upstream from streamflow-gaging station 01408500 or to the BB-LEH estuary was calculated.Groundwater input into the Barnegat Bay–Little Egg Harbor estuary from two main sources— indirect discharge from base

  3. What Can Hierarchies Do for Data Streams?

    DEFF Research Database (Denmark)

    Yin, Xuepeng; Pedersen, Torben Bach

    Much effort has been put into building data streams management systems for querying data streams. Here, data streams have been viewed as a flow of low-level data items, e.g., sensor readings or IP packet data. Stream query languages have mostly been SQL-based, with the STREAM and TelegraphCQ lang...