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Sample records for oscillating water table

  1. Flashing oscillation in pool water

    International Nuclear Information System (INIS)

    Takamasa, Tomoji; Kondo, Koichi; Hazuku, Tatsuya

    1996-01-01

    This paper presents an experimental study of high-pressure saturated water discharging into the pool water. The purpose of the experiment is to clarify the phenomena that occur in blow-down of high-pressure saturated water from the pressure vessel into the water-filled containment in the case of a wall-crack accident or a LOCA in an advanced reactor. The results revealed that a flashing oscillation (FO) occurs when high-pressure saturated water discharges into the pool water, under specified experimental settings. The range of the flashing oscillates between a point very close to and some distance from the vent hole. The pressures in the vent tube and pool water vary according to the flashing oscillation. The pressure oscillation and frequency of flashing position might be caused by the balancing action between the supply of saturated water, flashing at the control volume and its condensation on the steam-water interface. A linear analysis was conducted using a spherical flashing bubble model. The period of the flashing oscillation in the experiments can be explained by theoretical analysis

  2. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  3. Separation control with fluidic oscillators in water

    Science.gov (United States)

    Schmidt, H.-J.; Woszidlo, R.; Nayeri, C. N.; Paschereit, C. O.

    2017-08-01

    The present study assesses the applicability of fluidic oscillators for separation control in water. The first part of this work evaluates the properties of the fluidic oscillators including frequency, cavitation effects, and exerted thrust. Derived from the governing internal dynamics, the oscillation frequency is found to scale directly with the jet's exit velocity and the size of the fluidic oscillator independent of the working fluid. Frequency data from various experiments collapse onto a single curve. The occurrence of cavitation is examined by visual inspection and hydrophone measurements. The oscillation frequency is not affected by cavitation because it does not occur inside the oscillators. The spectral information obtained with the hydrophone provide a reliable indicator for the onset of cavitation at the exit. The performance of the fluidic oscillators for separation control on a bluff body does not seem to be affected by the presence of cavitation. The thrust exerted by an array of fluidic oscillators with water as the working fluid is measured to be even larger than theoretically estimated values. The second part of the presented work compares the performance of fluidic oscillators for separation control in water with previous results in air. The array of fluidic oscillators is installed into the rear end of a bluff body model. The drag improvements based on force balance measurements agree well with previous wind tunnel experiments on the same model. The flow field is examined by pressure measurements and with particle image velocimetry. Similar performance and flow field characteristics are observed in both water and air.

  4. WATER HAMMER OSCILLATIONS IN THE IRRIGATION FACILITIES

    Science.gov (United States)

    Kurata, Kouichi; Sasaki, Katsuhito; Makihata, Toshiaki

    In case a gate installed at the end of discharge conduit is vibrating during discharge, or an air valve is vibrating during water-filling operation into the conduit pipe between main gate and auxiliary gate, and vibration period tv is larger than tc (water hammer propagation time) that is equivalent to the phenomenon of slow closure, there is a possibility that water hammer oscillation in the discharge conduit could be induced. In this paper, by using two case examples, vibration phenomena transmitted to each part are analyzed, on the basis of water pressure fluctuation and pressure wave propagation due to occurrence of water hammer oscillation.

  5. Water table fluctuations and soil biogeochemistry: An experimental approach using an automated soil column system

    Science.gov (United States)

    Rezanezhad, F.; Couture, R.-M.; Kovac, R.; O'Connell, D.; Van Cappellen, P.

    2014-02-01

    Water table fluctuations significantly affect the biological and geochemical functioning of soils. Here, we introduce an automated soil column system in which the water table regime is imposed using a computer-controlled, multi-channel pump connected to a hydrostatic equilibrium reservoir and a water storage reservoir. The potential of this new system is illustrated by comparing results from two columns filled with 45 cm of the same homogenized riparian soil. In one soil column the water table remained constant at -20 cm below the soil surface, while in the other the water table oscillated between the soil surface and the bottom of the column, at a rate of 4.8 cm d-1. The experiment ran for 75 days at room temperature (25 ± 2 °C). Micro-sensors installed at -10 and -30 cm below the soil surface in the stable water table column recorded constant redox potentials on the order of 600 and -200 mV, respectively. In the fluctuating water table column, redox potentials at the same depths oscillated between oxidizing (∼700 mV) and reducing (∼-100 mV) conditions. Pore waters collected periodically and solid-phase analyses on core material obtained at the end of the experiment highlighted striking geochemical differences between the two columns, especially in the time series and depth distributions of Fe, Mn, K, P and S. Soil CO2 emissions derived from headspace gas analysis exhibited periodic variations in the fluctuating water table column, with peak values during water table drawdown. Transient redox conditions caused by the water table fluctuations enhanced microbial oxidation of soil organic matter, resulting in a pronounced depletion of particulate organic carbon in the midsection of the fluctuating water table column. Denaturing Gradient Gel Electrophoresis (DGGE) revealed the onset of differentiation of the bacterial communities in the upper (oxidizing) and lower (reducing) soil sections, although no systematic differences in microbial community structure

  6. Cokriging model for estimation of water table elevation

    International Nuclear Information System (INIS)

    Hoeksema, R.J.; Clapp, R.B.; Thomas, A.L.; Hunley, A.E.; Farrow, N.D.; Dearstone, K.C.

    1989-01-01

    In geological settings where the water table is a subdued replica of the ground surface, cokriging can be used to estimate the water table elevation at unsampled locations on the basis of values of water table elevation and ground surface elevation measured at wells and at points along flowing streams. The ground surface elevation at the estimation point must also be determined. In the proposed method, separate models are generated for the spatial variability of the water table and ground surface elevation and for the dependence between these variables. After the models have been validated, cokriging or minimum variance unbiased estimation is used to obtain the estimated water table elevations and their estimation variances. For the Pits and Trenches area (formerly a liquid radioactive waste disposal facility) near Oak Ridge National Laboratory, water table estimation along a linear section, both with and without the inclusion of ground surface elevation as a statistical predictor, illustrate the advantages of the cokriging model

  7. Decreased summer water table depth affects peatland vegetation

    NARCIS (Netherlands)

    Breeuwer, A.J.G.; Robroek, B.J.M.; Limpens, J.; Heijmans, M.M.P.D.; Schouten, M.G.C.; Berendse, F.

    2009-01-01

    Climate change can be expected to increase the frequency of summer droughts and associated low water tables in ombrotrophic peatlands. We studied the effects of periodic water table drawdown in a mesocosm experiment. Mesocosms were collected in Southern Sweden, and subsequently brought to an

  8. Free product recovery at spill sites with fluctuating water tables

    International Nuclear Information System (INIS)

    Parker, J.C.; Katyal, A.K.; Zhu, J.L.; Kremesec, V.J.; Hockman, E.L.

    1992-01-01

    Spills and leaks of hydrocarbons from underground storage tanks, pipelines and other facilities pose a serious potential for groundwater contamination which can be very costly to remediate. The severity of the impacts and the cost of remediation can be reduced by various means. Lateral spreading of free phase hydrocarbons on the groundwater table can be prevented by pumping water to control the hydraulic gradient. Recovery of floating product may be performed by skimming hydrocarbons from wells, usually in combination with water pumping to increase the gradient. The environmental variables (water table gradient, water table fluctuations due to regional recovery wells, rates of water pumping)

  9. A review of oscillating water columns.

    Science.gov (United States)

    Heath, T V

    2012-01-28

    This paper considers the history of oscillating water column (OWC) systems from whistling buoys to grid-connected power generation systems. The power conversion from the wave resource through to electricity via pneumatic and shaft power is discussed in general terms and with specific reference to Voith Hydro Wavegen's land installed marine energy transformer (LIMPET) plant on the Scottish island of Islay and OWC breakwater systems. A report on the progress of other OWC systems and power take-off units under commercial development is given, and the particular challenges faced by OWC developers reviewed.

  10. Beaver Mediated Water Table Dynamics in Mountain Peatlands

    Science.gov (United States)

    Karran, D. J.; Westbrook, C.; Bedard-Haughn, A.

    2016-12-01

    Water table dynamics play an important role in the ecological and biogeochemical processes that regulate carbon and water storage in peatlands. Beaver are common in these habitats and the dams they build have been shown to raise water tables in other environments. However, the impact of beaver dams in peatlands, where water tables rest close to the surface, has yet to be determined. We monitored a network of 50 shallow wells in a Canadian Rocky Mountain peatland for 6 years. During this period, a beaver colony was maintaining a number of beaver ponds for four years until a flood event removed the colony from the area and breached some of the dams. Two more years of data were collected after the flood event to assess whether the dams enhanced groundwater storage. Beaver dams raised water tables just as they do in other environments. Furthermore, water tables within 100 meters of beaver dams were more stable than those further away and water table stability overall was greater before the flood event. Our results suggest the presence/absence of beaver in peatlands has implications for groundwater water storage and overall system function.

  11. Numerical tables. Physical and chemical analyses of Rhine water 1984

    International Nuclear Information System (INIS)

    1984-01-01

    Tables present the methods of analysis and the data obtained on inorganic, organic, and radioactive impurities in Rhine water. The measuring stations were located in Switzerland, France, West Germany, and the Netherlands. (HP) [de

  12. Tables of the velocity of sound in sea water

    CERN Document Server

    Bark, L S; Meister, N A

    1964-01-01

    Tables of the Velocity of Sound in Sea Water contains tables of the velocity of sound in sea water computed on a ""Strela-3"" high-speed electronic computer and a T-5 tabulator at the Computational Center of the Academy of Sciences. Knowledge of the precise velocity of sound in sea water is of great importance when investigating sound propagations in the ocean and when solving practical problems involving the use of hydro-acoustic devices. This book demonstrates the computations made for the velocity of sound in sea water, which can be found in two ways: by direct measurement with the aid of s

  13. Empirical method for simulation of water tables by digital computers

    International Nuclear Information System (INIS)

    Carnahan, C.L.; Fenske, P.R.

    1975-09-01

    An empirical method is described for computing a matrix of water-table elevations from a matrix of topographic elevations and a set of observed water-elevation control points which may be distributed randomly over the area of interest. The method is applicable to regions, such as the Great Basin, where the water table can be assumed to conform to a subdued image of overlying topography. A first approximation to the water table is computed by smoothing a matrix of topographic elevations and adjusting each node of the smoothed matrix according to a linear regression between observed water elevations and smoothed topographic elevations. Each observed control point is assumed to exert a radially decreasing influence on the first approximation surface. The first approximation is then adjusted further to conform to observed water-table elevations near control points. Outside the domain of control, the first approximation is assumed to represent the most probable configuration of the water table. The method has been applied to the Nevada Test Site and the Hot Creek Valley areas in Nevada

  14. Relationships between water table and model simulated ET

    Science.gov (United States)

    Prem B. Parajuli; Gretchen F. Sassenrath; Ying Ouyang

    2013-01-01

    This research was conducted to develop relationships among evapotranspiration (ET), percolation (PERC), groundwater discharge to the stream (GWQ), and water table fluctuations through a modeling approach. The Soil and Water Assessment Tool (SWAT) hydrologic and crop models were applied in the Big Sunflower River watershed (BSRW; 7660 km2) within the Yazoo River Basin...

  15. Nitrogen Uptake in Soils under Different Water Table Depths ...

    African Journals Online (AJOL)

    A mathematical model was used to examine the interactions of NH4 + transport to rice roots, as well as to calculate root length densities required to relate N uptake to concentrations of NH4 + in solution around the rooting medium for three water treatments: water table 30 cm below the surface, 15 cm below the surface and ...

  16. Effect of water table dynamics on land surface hydrologic memory

    Science.gov (United States)

    Lo, Min-Hui; Famiglietti, James S.

    2010-11-01

    The representation of groundwater dynamics in land surface models has received considerable attention in recent years. Most studies have found that soil moisture increases after adding a groundwater component because of the additional supply of water to the root zone. However, the effect of groundwater on land surface hydrologic memory (persistence) has not been explored thoroughly. In this study we investigate the effect of water table dynamics on National Center for Atmospheric Research Community Land Model hydrologic simulations in terms of land surface hydrologic memory. Unlike soil water or evapotranspiration, results show that land surface hydrologic memory does not always increase after adding a groundwater component. In regions where the water table level is intermediate, land surface hydrologic memory can even decrease, which occurs when soil moisture and capillary rise from groundwater are not in phase with each other. Further, we explore the hypothesis that in addition to atmospheric forcing, groundwater variations may also play an important role in affecting land surface hydrologic memory. Analyses show that feedbacks of groundwater on land surface hydrologic memory can be positive, negative, or neutral, depending on water table dynamics. In regions where the water table is shallow, the damping process of soil moisture variations by groundwater is not significant, and soil moisture variations are mostly controlled by random noise from atmospheric forcing. In contrast, in regions where the water table is very deep, capillary fluxes from groundwater are small, having limited potential to affect soil moisture variations. Therefore, a positive feedback of groundwater to land surface hydrologic memory is observed in a transition zone between deep and shallow water tables, where capillary fluxes act as a buffer by reducing high-frequency soil moisture variations resulting in longer land surface hydrologic memory.

  17. Self-induced free surface oscillations caused by water jet

    International Nuclear Information System (INIS)

    Fukaya, M.; Madarame, H.; Okamoto, K.; Iida, M.; Someya, S.

    1995-01-01

    The interaction between the high speed flow and the free surfaces could induced surface oscillations. Recently, some kinds of self-induced free surface oscillations caused by water jet were discovered, e.g., a self-induced sloshing, 'Jet-Flutter' and a self-induced manometer oscillation. These oscillations have many different characteristics with each other. In this study, the similarities and differences of these oscillations are examined, and the geometrical effects on the phenomena are experimentally investigated. The self-induced sloshing and the Jet-Flutter have different dimensionless traveling times, which suggests a difference in the energy supply mechanism. When the distance between the inlet and the outlet is small in a vessel, the self-induced manometer oscillation could occur in the multi-free-surface system. (author)

  18. Microtropography and water table fluctuation in a sphagnum mire

    Science.gov (United States)

    E.S. Verry

    1984-01-01

    A detailed organic soil profile description, 22 years of continuous water table records, and a hummock-hollow level survey were examined at a small Minnesota mire (a bog with remnants of poor fen vegetation). Variation in the level survey suggests that hollows be used to minimize variation when detailed topographic information is needed and to match profile...

  19. Modelling mid-span water table depth and drainage discharge ...

    African Journals Online (AJOL)

    2015-04-03

    Apr 3, 2015 ... were monitored in 1.7 m deep piezometers installed mid-way between two drains by using an electronic .... logical components in soils with shallow water tables. ..... dency of neither under-estimating nor over-estimating DDs,.

  20. Distribution Channel Intensity among Table Water Producers in Nigeria

    Directory of Open Access Journals (Sweden)

    Joseph Edewor Agbadudu

    2017-09-01

    Full Text Available Planning for and making reasonable decisions regarding reaching the target market with an organization’s product is a critical task on the part of management, which involves a careful evaluation and selection of its channel structure and intensity.This study therefore examines distribution channel intensity among table water producers in Edo State, Nigeria. The focus of the study is to ascertain the variables that significantly predict distribution intensity among the firms in the table water industry in Edo State. The study seeks to proffer answer to fundamental question of why brands within a single category of a given consumer good differ significantly in their distribution intensity. Using a survey research design, the data used for this study were obtained by taking a sample of 110 table water firms within the three senatorial districts in the State. The data obtained were presented and analyzed using different statistical tools such as mean and multiple regression through Statistical Packages for Social Sciences (SPSS version 22 software. Findings revealed that manufacturers’ target focus, manufacturers’ support program, brand quality and level of firm’s technological advancement were significant predictors of distribution channel intensity among the industrial players in table water industry in the State. Based on the findings, the study recommended that table water firms within the State can secure a competitive edge over their fellow counterpart in the industry by designing an optimal distribution intensity that will meet up their marketing objectives. It is also recommended that the adoption of modern technology in form of online sales is an efficient way of sales and distribution which could be used to enhance their distribution techniques if there is a need to cut down on middle men due to increased cost. The study concluded that optimal distribution intensity could be achieved not by mere imitation of competitors but through

  1. An alternating voltage battery with two salt-water oscillators

    Science.gov (United States)

    Cervellati, Rinaldo; Soldà, Roberto

    2001-05-01

    We built a simple alternating voltage battery that periodically reverses value and sign of its electromotive force (emf). This battery consists of two coupled concentration salt-water oscillators that are phase shifted by initially extracting some drops of salt solution from one of the two oscillators. Although the actual frequency (period: ˜30 s) and emf (˜±55 mV) is low, our battery is suitable to demonstrate a practical application of oscillating systems in the physical, chemical, or biological laboratory for undergraduates. Interpretation of the phenomenon is given.

  2. Woody riparian vegetation response to different alluvial water table regimes

    Science.gov (United States)

    Shafroth, P.B.; Stromberg, J.C.; Patten, D.T.

    2000-01-01

    Woody riparian vegetation in western North American riparian ecosystems is commonly dependent on alluvial groundwater. Various natural and anthropogenic mechanisms can cause groundwater declines that stress riparian vegetation, but little quantitative information exists on the nature of plant response to different magnitudes, rates, and durations of groundwater decline. We observed groundwater dynamics and the response of Populus fremontii, Salix gooddingii, and Tamarix ramosissima saplings at 3 sites between 1995 and 1997 along the Bill Williams River, Arizona. At a site where the lowest observed groundwater level in 1996 (-1.97 m) was 1.11 m lower than that in 1995 (-0.86 m), 92-100% of Populus and Salix saplings died, whereas 0-13% of Tamarix stems died. A site with greater absolute water table depths in 1996 (-2.55 m), but less change from the 1995 condition (0.55 m), showed less Populus and Salix mortality and increased basal area. Excavations of sapling roots suggest that root distribution is related to groundwater history. Therefore, a decline in water table relative to the condition under which roots developed may strand plant roots where they cannot obtain sufficient moisture. Plant response is likely mediated by other factors such as soil texture and stratigraphy, availability of precipitation-derived soil moisture, physiological and morphological adaptations to water stress, and tree age. An understanding of the relationships between water table declines and plant response may enable land and water managers to avoid activities that are likely to stress desirable riparian vegetation.

  3. Future water table rise at Yucca Mountain: A regulatory perspective

    International Nuclear Information System (INIS)

    Coleman, N.M.

    1995-01-01

    The U.S. Nuclear Regulatory Commission staff has developed a program of Systematic Regulatory Analysis (SRA). The purpose of this program is to ensure that important technical issues related to compliance with 10 CFR Part 60 will be identified before receipt of a license application. A plan is being developed to review the U.S. Department of Energy's (DOE's) demonstration of compliance in the license application for each part of the regulation. Under the siting criteria of NRC's Part 60, one of the potentially adverse conditions is the possibility that the water table may rise high enough to saturate a repository in the unsaturated zone. DOE must evaluate this and other conditions in a license application for a geologic repository site. DOE's evaluation must show compliance with the requirements of Part 60 with reasonable assurance. This paper describes the NRC staff's preliminary plans to review DOE's demonstration of compliance, including assumptions about a future rise of the water table

  4. Water table monitoring in a mined riparian zone

    Directory of Open Access Journals (Sweden)

    Thomaz Marques Cordeiro Andrade

    2010-04-01

    Full Text Available The objective of this study was to test an easily fabricated tool that assist in the manual installation of piezometers, as well as water table monitor in the research site, located at the Gualaxo do Norte River Watershed, state of Minas Gerais, Brazil. The tool is made of iron pipes and is a low-cost alternative for shallow groundwater observation wells. The measurements were done in a riparian zone after being gold mined, when vegetation and upper soil layers were removed. The wells were installed in three areas following a transect from the river bank. The method was viable for digging up to its maximum depth of 3 meters in a low resistance soil and can be improved to achieve a better resistance over impact and its maximum depth of perforation. Water table levels varied distinctly according to its depth in each point. It varies most in the more shallow wells in different areas, while it was more stable in the deeper ones. The water table profile reflected the probably profile f the terrain and can be a reference for its leveling in reconstitution of degraded banks where upper layers of the soil were removed. Groundwater monitoring can be also an indicator of the suitability of the substrate for soil reconstitution in terms of the maintenance of an infiltration capacity similar to the original material.

  5. Stochastic analysis of unsaturated steady flows above the water table

    Science.gov (United States)

    Severino, Gerardo; Scarfato, Maddalena; Comegna, Alessandro

    2017-08-01

    Steady flow takes place into a three-dimensional partially saturated porous medium where, due to their spatial variability, the saturated conductivity Ks, and the relative conductivity Kr are modeled as random space functions (RSF)s. As a consequence, the flow variables (FVs), i.e., pressure-head and specific flux, are also RSFs. The focus of the present paper consists into quantifying the uncertainty of the FVs above the water table. The simple expressions (most of which in closed form) of the second-order moments pertaining to the FVs allow one to follow the transitional behavior from the zone close to the water table (where the FVs are nonstationary), till to their far-field limit (where the FVs become stationary RSFs). In particular, it is shown how the stationary limits (and the distance from the water table at which stationarity is attained) depend upon the statistical structure of the RSFs Ks, Kr, and the infiltrating rate. The mean pressure head >> has been also computed, and it is expressed as =Ψ0>(1+ψ>), being ψ a characteristic heterogeneity function which modifies the zero-order approximation Ψ0 of the pressure head (valid for a vadose zone of uniform soil properties) to account for the spatial variability of Ks and Kr. Two asymptotic limits, i.e., close (near field) and away (far field) from the water table, are derived into a very general manner, whereas the transitional behavior of ψ between the near/far field can be determined after specifying the shape of the various input soil properties. Besides the theoretical interest, results of the present paper are useful for practical purposes, as well. Indeed, the model is tested against to real data, and in particular it is shown how it is possible for the specific case study to grasp the behavior of the FVs within an environment (i.e., the vadose zone close to the water table) which is generally very difficult to access by direct inspection.

  6. Changes in vegetative communities and water table dynamics following timber harvesting in small headwater streams

    Science.gov (United States)

    B. Choi; J.C. Dewey; J. A. Hatten; A.W. Ezell; Z. Fan

    2012-01-01

    In order to better understand the relationship between vegetation communities and water table in the uppermost portions (ephemeral–intermittent streams) of headwater systems, seasonal plot-based field characterizations of vegetation were used in conjunction with monthly water table measurements. Vegetation, soils, and water table data were examined to determine...

  7. Vertical vibration and shape oscillation of acoustically levitated water drops

    International Nuclear Information System (INIS)

    Geng, D. L.; Xie, W. J.; Yan, N.; Wei, B.

    2014-01-01

    We present the vertical harmonic vibration of levitated water drops within ultrasound field. The restoring force to maintain such a vibration mode is provided by the resultant force of acoustic radiation force and drop gravity. Experiments reveal that the vibration frequency increases with the aspect ratio for drops with the same volume, which agrees with the theoretical prediction for those cases of nearly equiaxed drops. During the vertical vibration, the floating drops undergo the second order shape oscillation. The shape oscillation frequency is determined to be twice the vibration frequency.

  8. Vertical vibration and shape oscillation of acoustically levitated water drops

    Energy Technology Data Exchange (ETDEWEB)

    Geng, D. L.; Xie, W. J.; Yan, N.; Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2014-09-08

    We present the vertical harmonic vibration of levitated water drops within ultrasound field. The restoring force to maintain such a vibration mode is provided by the resultant force of acoustic radiation force and drop gravity. Experiments reveal that the vibration frequency increases with the aspect ratio for drops with the same volume, which agrees with the theoretical prediction for those cases of nearly equiaxed drops. During the vertical vibration, the floating drops undergo the second order shape oscillation. The shape oscillation frequency is determined to be twice the vibration frequency.

  9. Critical Power Response to Power Oscillations in Boiling Water Reactors

    International Nuclear Information System (INIS)

    Farawila, Yousef M.; Pruitt, Douglas W.

    2003-01-01

    The response of the critical power ratio to boiling water reactor (BWR) power oscillations is essential to the methods and practice of mitigating the effects of unstable density waves. Previous methods for calculating generic critical power response utilized direct time-domain simulations of unstable reactors. In this paper, advances in understanding the nature of the BWR oscillations and critical power phenomena are combined to develop a new method for calculating the critical power response. As the constraint of the reactor state - being at or slightly beyond the instability threshold - is removed, the new method allows the calculation of sensitivities to different operation and design parameters separately, and thus allows tighter safety margins to be used. The sensitivity to flow rate and the resulting oscillation frequency change are given special attention to evaluate the extension of the oscillation 'detect-and-suppress' methods to internal pump plants where the flow rate at natural circulation and oscillation frequency are much lower than jet pump plants

  10. Links between climate change, water-table depth, and water chemistry in a mineralized mountain watershed

    Science.gov (United States)

    Manning, Andrew H.; Verplanck, Philip L.; Caine, Jonathan S.; Todd, Andrew S.

    2013-01-01

    Recent studies suggest that climate change is causing rising solute concentrations in mountain lakes and streams. These changes may be more pronounced in mineralized watersheds due to the sensitivity of sulfide weathering to changes in subsurface oxygen transport. Specific causal mechanisms linking climate change and accelerated weathering rates have been proposed, but in general remain entirely hypothetical. For mineralized watersheds, a favored hypothesis is that falling water tables caused by declining recharge rates allow an increasing volume of sulfide-bearing rock to become exposed to air, thus oxygen. Here, we test the hypothesis that falling water tables are the primary cause of an increase in metals and SO4 (100-400%) observed since 1980 in the Upper Snake River (USR), Colorado. The USR drains an alpine watershed geologically and climatologically representative of many others in mineralized areas of the western U.S. Hydrologic and chemical data collected from 2005 to 2011 in a deep monitoring well (WP1) at the top of the USR watershed are utilized. During this period, both water table depths and groundwater SO4 concentrations have generally increased in the well. A numerical model was constructed using TOUGHREACT that simulates pyrite oxidation near WP1, including groundwater flow and oxygen transport in both saturated and unsaturated zones. The modeling suggests that a falling water table could produce an increase in metals and SO4 of a magnitude similar to that observed in the USR (up to 300%). Future water table declines may produce limited increases in sulfide weathering high in the watershed because of the water table dropping below the depth of oxygen penetration, but may continue to enhance sulfide weathering lower in the watershed where water tables are shallower. Advective air (oxygen) transport in the unsaturated zone caused by seasonally variable recharge and associated water table fluctuations was found to have little influence on pyrite

  11. Experimental researches on the single-bubble rising behavior in the water excited by oscillation

    International Nuclear Information System (INIS)

    Cai Jiejin; Zhong Minghuang; Wang Ke; Zeng Xixiang; Lin Yongcheng; WATANABE Tadashi

    2014-01-01

    This study try to carry out experiments to research the bubble rising behavior in the water excited by oscillation and focus on its dynamics characteristics under the oscillation condition with different oscillation frequencies and amplitudes, and get the relationship between bubble's characteristic parameter, such as the bubble shape, rising velocity, etc, and the influence parameters of time, oscillation frequencies, amplitudes, etc. The rising rule of the single bubble in the water excited by oscillation has been concluded. (authors)

  12. Study on the oscillation dissolved behavior of oxysophocarpine in water

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.X., E-mail: mingtian8001@163.com [Department of Chemistry and Chemical Engineering, Baoji University of Arts and Science, Baoji, Shaanxi 721013 (China); Zhao, W.W.; Pu, X.H. [Department of Chemistry and Chemical Engineering, Baoji University of Arts and Science, Baoji, Shaanxi 721013 (China)

    2012-06-10

    Highlights: Black-Right-Pointing-Pointer The dissolution enthalpies of oxysophocarpine in water was measured using a RD496-2000 Calvet microcalorimeter. Black-Right-Pointing-Pointer The results show that the dissolution process possessed an endothermic and exothermic oscillation behavior. Black-Right-Pointing-Pointer A series of thermodynamics functions and half-life period were obtained from thermodynamic and kinetic calculations. - Abstract: In this paper, the enthalpies of dissolution of oxysophocarpine in water were measured using a RD496-2000 Calvet microcalorimeter at 298.15 K under atmospheric pressure, showing that the dissolution process was an endothermic and exothermic oscillation behavior. A series of thermodynamics functions and the half-life were obtained by thermodynamic and kinetic methods. The results show that this work not only provide a simple method for the determination of the half-life for a drug but also offer a theoretical reference for the clinical application of resveratrol.

  13. Study on the oscillation dissolved behavior of oxysophocarpine in water

    International Nuclear Information System (INIS)

    Li, Z.X.; Zhao, W.W.; Pu, X.H.

    2012-01-01

    Highlights: ► The dissolution enthalpies of oxysophocarpine in water was measured using a RD496-2000 Calvet microcalorimeter. ► The results show that the dissolution process possessed an endothermic and exothermic oscillation behavior. ► A series of thermodynamics functions and half-life period were obtained from thermodynamic and kinetic calculations. - Abstract: In this paper, the enthalpies of dissolution of oxysophocarpine in water were measured using a RD496-2000 Calvet microcalorimeter at 298.15 K under atmospheric pressure, showing that the dissolution process was an endothermic and exothermic oscillation behavior. A series of thermodynamics functions and the half-life were obtained by thermodynamic and kinetic methods. The results show that this work not only provide a simple method for the determination of the half-life for a drug but also offer a theoretical reference for the clinical application of resveratrol.

  14. African Mahogany transpiration with Granier method and water table lysimeter

    Directory of Open Access Journals (Sweden)

    Ana C. O. Sérvulo

    Full Text Available ABSTRACT The thermal dissipation probe (Granier method is useful in the water deficit monitoring and irrigation management of African Mahogany, but its model needs proper adjustment. This paper aimed to adjust and validate the Granier sap flux model to estimate African Mahogany transpiration, measure transpiration using lysimeter and relate it to atmospheric water demand. Weather conditions, transpiration and sap flux were monitored in three units of 2.5-year-old African Mahogany trees in constant water table lysimeter, in Goiânia, GO. Sapwood area (SA, leaf area (LA, transpiration measured by lysimeter (TLYS and estimated by sap flux (TSF were evaluated. The SA comprised 55.24% of the trunk’s transversal section. The LA varied from 11.95 to 10.66 m2. TLYS and TSF varied from 2.94 to 29.31 and from 0.94 to 15.45 L d-1, respectively. The original model underestimated transpiration by 44.4%, being the adjusted equation F = 268.25 . k1.231. SA was significant (F < 0.05. Due the root confinement, the transpiration showed low correlation, but positive, with the atmospheric water demand.

  15. Optimization of irrigation water in stone fruit and table grapes

    Science.gov (United States)

    de la Rosa, Jose Mª; Castillo, Cristina; Temnani, Abdel; Pérez-Pastor, Alejandro

    2017-04-01

    In water scarcity areas, it must be highlighted that the maximum productions of the crops do not necessarily imply maximum profitability. Therefore, during the last years a special interest in the development of deficit irrigation strategies based on significant reductions of the seasonal ET without affecting production or quality has been observed. The strategies of regulated deficit irrigation (RDI) are based on the reduction of water supply during non critical periods, the covering of water needs during critical periods and maximizing, at the same time, the production by unit of applied water. The main objective of this experiment was to implement, demonstrate and disseminate a sustainable irrigation strategy based on deficit irrigation to promote its large scale acceptance and use in woody crops in Mediterranean agroecosystems, characterized by water scarcity, without affecting the quality standards demanded by exportation markets. Five demonstration plots were established in representative crops of the irrigating community of Campotejar (Murcia, Spain): i) Peach trees, cv. catherina in the "Periquitos" farm; ii) Apricot trees, cv. "Red Carlet" in "La Hoya del Fenazar" farm; iii) Nectarine trees, cv. Viowhite in "Agrícola Don Fernando" farm; iv) Table grape, cv "Crimson Seedless" in "La Hornera" farm; and v) Paraguayan cv. carioca in "The Hornera" farm. In each demonstration plot, at least two irrigation treatments were established: i) Control (CTL), irrigated to ensure non-limiting water conditions (120% of crop evapotranspiration) and ii) Regulated deficit irrigation (RDI) irrigated as CTL during critical periods and decreasing irrigation in non-critical periods. The plant water status indicators evaluated were midday stem water potential and Trunk Diameter Fluctuation derived indices: maximum daily shrinkage (MDS) and trunk daily growth rate (TGR); vegetative growth of the different crops from trunk diameter and pruning dry weight, fruit growth and fruit

  16. A time series approach to inferring groundwater recharge using the water table fluctuation method

    Science.gov (United States)

    Crosbie, Russell S.; Binning, Philip; Kalma, Jetse D.

    2005-01-01

    The water table fluctuation method for determining recharge from precipitation and water table measurements was originally developed on an event basis. Here a new multievent time series approach is presented for inferring groundwater recharge from long-term water table and precipitation records. Additional new features are the incorporation of a variable specific yield based upon the soil moisture retention curve, proper accounting for the Lisse effect on the water table, and the incorporation of aquifer drainage so that recharge can be detected even if the water table does not rise. A methodology for filtering noise and non-rainfall-related water table fluctuations is also presented. The model has been applied to 2 years of field data collected in the Tomago sand beds near Newcastle, Australia. It is shown that gross recharge estimates are very sensitive to time step size and specific yield. Properly accounting for the Lisse effect is also important to determining recharge.

  17. Water-table fluctuations in the Amargosa Desert, Nye County, Nevada

    International Nuclear Information System (INIS)

    Paces, James B.; Whelan, Joseph

    2001-01-01

    Pleistocene ground-water discharge deposits approximately 20 km southwest of Yucca Mountain were previously thought to represent pluvial water-table rises of 80 to 120 m. Data from new boreholes at two of the three discharge sites indicate that the modern water-table is at depths of only 17 to 30 m and that this shallow water is part of the regional ground-water flow system rather than being perched. Calcite in equilibrium with this modern ground water would have isotopic compositions similar to those in Pleistocene calcite associated with the discharge deposits. Carbon and uranium isotopes in both ground water and discharge deposits imply that past discharge consisted of a mixture of both shallow and deep ground water. These data limit Pleistocene water-table fluctuations at the specified Amargosa Desert discharge sites to between 17 and 30 m and eliminate the need to invoke large water-table rises

  18. Numerical tables on physical and chemical analyses of Rhine water

    International Nuclear Information System (INIS)

    1982-01-01

    Tables on the places of measurement, the sampling methods and the methods of analysis used. The numerical tables of the measurement results are broken down in general parameters, organic, entrophicating and anorganic substances, orgnic micro-pollutants and radioactivity. (GG) [de

  19. Response of anaerobic carbon cycling to water table manipulation in an Alaskan rich fen

    Science.gov (United States)

    E.S. Kane; M.R. Chivers; M.S. Turetsky; C.C. Treat; D.G. Petersen; M. Waldrop; J.W. Harden; A.D. McGuire

    2013-01-01

    To test the effects of altered hydrology on organic soil decomposition, we investigated CO2 and CH4 production potential of rich-fen peat (mean surface pH = 6.3) collected from a field water table manipulation experiment including control, raised and lowered water table treatments. Mean anaerobic CO2...

  20. Non-Axisymmetric Oscillation of Acoustically Levitated Water Drops at Specific Frequencies

    International Nuclear Information System (INIS)

    Chang-Le, Shen; Wen-Jun, Xie; Bing-Bo, Wei

    2010-01-01

    A category of non-axisymmetric oscillations of acoustically levitated water drops was observed. These oscillations can be qualitatively described by superposing a sectorial oscillating term upon the initial oblate shape resulting from the effect of acoustic radiation pressure. The oscillation frequencies are around 25 Hz for the 2-lobed mode and exactly 50 Hz for the 3- and 4-lobed modes. These oscillations were excited by the disturbance from the power supply. For the same water drop, higher mode oscillations were observed with more oblate initial shape, indicating that the eigenfrequencies of these non-axisymmetric oscillations decrease with increasing initial distortion. The maximum velocity and acceleration within the oscillating drop can attain 0.3m·s −1 and 98.7m·s −2 respectively, resulting in strong fluid convection and enhanced heat and mass transfer. (condensed matter: structure, mechanical and thermal properties)

  1. Changes in water table elevation at Yucca Mountain in response to seismic events

    International Nuclear Information System (INIS)

    Arnold, B.W.

    1996-01-01

    Investigation of mechanisms which could significantly alter the elevation of the water table at Yucca Mountain are motivated by the potential impacts such an occurrence would have on the performance of a high-level radioactive waste repository. In particular, we would like to evaluate the possibility of flooding a repository by water-table excursions. Changes in the water table could occur as relatively transient phenomena in response to seismic events by the seismic pumping mechanism. Quantitative evaluation of possible fluctuations of groundwater following earthquakes was undertaken in support of performance assessment calculations including seismicity

  2. Numerical tables on physical and chemical analyses of Rhine water 1983

    International Nuclear Information System (INIS)

    1984-01-01

    The numerical tables contain the measuring results of the physical-chemical studies on the Rhine water for the year 1983. The tables are arranged by general parameters, organic matter, eutrophicating substances, anorganic matter, metals, organic micropollution as well as by radioactivity (total alpha- or beta- and T-activity). (MM) [de

  3. Developing Automatic Water Table Control System for Reducing Greenhouse Gas Emissions from Paddy Fields

    Science.gov (United States)

    Arif, C.; Fauzan, M. I.; Satyanto, K. S.; Budi, I. S.; Masaru, M.

    2018-05-01

    Water table in rice fields play important role to mitigate greenhouse gas (GHG) emissions from paddy fields. Continuous flooding by maintenance water table 2-5 cm above soil surface is not effective and release more GHG emissions. System of Rice Intensification (SRI) as alternative rice farming apply intermittent irrigation by maintaining lower water table is proven can reduce GHG emissions reducing productivity significantly. The objectives of this study were to develop automatic water table control system for SRI application and then evaluate the performances. The control system was developed based on fuzzy logic algorithms using the mini PC of Raspberry Pi. Based on laboratory and field tests, the developed system was working well as indicated by lower MAPE (mean absolute percentage error) values. MAPE values for simulation and field tests were 16.88% and 15.80%, respectively. This system can save irrigation water up to 42.54% without reducing productivity significantly when compared to manual irrigation systems.

  4. Mechanism for migration of light nonaqueous phase liquids beneath the water table

    International Nuclear Information System (INIS)

    Krueger, J.P.; Portman, M.E.

    1991-01-01

    This paper reports on an interesting transport mechanism may account for the presence of light nonaqueous phase liquid (LNAPL) found beneath the water table in fine-grained aquifers. During the course of two separate site investigations related to suspected releases from underground petroleum storage tanks, LNAPL was found 7 to 10 feet below the regional water table. In both cases, the petroleum was present within a sand seam which was encompassed within a deposit of finer-grained sediments. The presence of LNAPL below the water table is uncommon; typically, LNAPL is found floating on the water table or on the capillary fringe. The occurrence of LNAPL below the water table could have resulted from fluctuating regional water levels which allowed the petroleum to enter the sand when the water table was a lower stage or, alternately, could have occurred as a result of the petroleum depressing the water table beneath the level of the sand. In fine-grained soils where the lateral migration rate is low, the infiltrating LNAPL may depress the water table to significant depth. The LNAPL may float on the phreatic surface with the bulk of its volume beneath the phreatic surface. Once present in the sand and surrounded by water-saturated fine-grained sediments, capillary forces prevent the free movement of the petroleum back across the boundary from the coarse-grained sediments to the fine-grained sediments. Tapping these deposits with a coarser grained filter packed monitoring well releases the LNAPL, which may accumulate to considerable thickness in the monitoring well

  5. Contribution of vegetation and water table on isoprene emission from boreal peatland microcosms

    DEFF Research Database (Denmark)

    Tiiva, Päivi; Faubert, Patrick; Räty, Sanna

    2009-01-01

    emission in these naturally wet ecosystems, although water table is predicted to decline due to climate warming. We studied the relative contribution of mosses vs. vascular plants to isoprene emission in boreal peatland microcosms in growth chambers by removing either vascular vegetation or both vascular...... hollows with intact vegetation, 45 ± 6 µg m-2 h-1, was decreased by 25% under water table drawdown. However, water table drawdown reduced net ecosystem carbon dioxide (CO2) exchange more dramatically than isoprene emission. Isoprene emission strongly correlated with both CO2 exchange and methane emission......Boreal peatlands are substantial sources of isoprene, a reactive hydrocarbon. However, it is not known how much mosses, vascular plants and peat each contribute to isoprene emission from peatlands. Furthermore, there is no information on the effects of declining water table depth on isoprene...

  6. Diffusive-dispersive mass transfer in the capillary fringe: Impact of water table fluctuations and heterogeneities

    DEFF Research Database (Denmark)

    Grathwohl, Peter; Haberer, Cristina; Ye, Yu

    Diffusive–dispersive mass transfer in the capillary fringe is important for many groundwater quality issues such as transfer of volatile compounds into (and out of) the groundwater, the supply of oxygen for aerobic degradation of hydrocarbons as well as for precipitation of minerals (e.g. iron...... hydroxides). 2D-laboratory scale experiments were used to investigate the transfer of oxygen into groundwater under non-reactive and reactive conditions, at steady state and with water table fluctuations. Results show that transfer of oxygen is limited by transverse dispersion in the capillary fringe...... and the dispersion coefficients are the same as below the water table. Water table fluctuations cause temporarily increased fluxes of oxygen into groundwater during draining conditions and entrapped air after water table rise. High-permeability inclusions in the capillary fringe enhance mass transfer of oxygen...

  7. Water property lookup table (sanwat) for use with the two-phase computational code shaft

    International Nuclear Information System (INIS)

    Sherman, M.P.; Eaton, R.R.

    1980-10-01

    A lookup table for water thermodynamic and transport properties (SANWAT) has been constructed for use with the two-phase computational code, SHAFT. The table, which uses density and specific internal energy as independent variables, covers the liquid, two-phase, and vapor regions. The liquid properties of water are contained in a separate subtable in order to obtain high accuracy for this nearly incompressible region that is frequently encountered in studies of the characteristics of nuclear-waste repositories

  8. Water table tests of proposed heat transfer tunnels for small turbine vanes

    Science.gov (United States)

    Meitner, P. L.

    1974-01-01

    Water-table flow tests were conducted for proposed heat-transfer tunnels which were designed to provide uniform flow into their respective test sections of a single core engine turbine vane and a full annular ring of helicopter turbine vanes. Water-table tests were also performed for the single-vane test section of the core engine tunnel. The flow in the heat-transfer tunnels was shown to be acceptable.

  9. Enhancing Groundwater Cost Estimation with the Interpolation of Water Tables across the United States

    Science.gov (United States)

    Rosli, A. U. M.; Lall, U.; Josset, L.; Rising, J. A.; Russo, T. A.; Eisenhart, T.

    2017-12-01

    Analyzing the trends in water use and supply across the United States is fundamental to efforts in ensuring water sustainability. As part of this, estimating the costs of producing or obtaining water (water extraction) and the correlation with water use is an important aspect in understanding the underlying trends. This study estimates groundwater costs by interpolating the depth to water level across the US in each county. We use Ordinary and Universal Kriging, accounting for the differences between aquifers. Kriging generates a best linear unbiased estimate at each location and has been widely used to map ground-water surfaces (Alley, 1993).The spatial covariates included in the universal Kriging were land-surface elevation as well as aquifer information. The average water table is computed for each county using block kriging to obtain a national map of groundwater cost, which we compare with survey estimates of depth to the water table performed by the USDA. Groundwater extraction costs were then assumed to be proportional to water table depth. Beyond estimating the water cost, the approach can provide an indication of groundwater-stress by exploring the historical evolution of depth to the water table using time series information between 1960 and 2015. Despite data limitations, we hope to enable a more compelling and meaningful national-level analysis through the quantification of cost and stress for more economically efficient water management.

  10. Stochastic estimation of plant-available soil water under fluctuating water table depths

    Science.gov (United States)

    Or, Dani; Groeneveld, David P.

    1994-12-01

    Preservation of native valley-floor phreatophytes while pumping groundwater for export from Owens Valley, California, requires reliable predictions of plant water use. These predictions are compared with stored soil water within well field regions and serve as a basis for managing groundwater resources. Soil water measurement errors, variable recharge, unpredictable climatic conditions affecting plant water use, and modeling errors make soil water predictions uncertain and error-prone. We developed and tested a scheme based on soil water balance coupled with implementation of Kalman filtering (KF) for (1) providing physically based soil water storage predictions with prediction errors projected from the statistics of the various inputs, and (2) reducing the overall uncertainty in both estimates and predictions. The proposed KF-based scheme was tested using experimental data collected at a location on the Owens Valley floor where the water table was artificially lowered by groundwater pumping and later allowed to recover. Vegetation composition and per cent cover, climatic data, and soil water information were collected and used for developing a soil water balance. Predictions and updates of soil water storage under different types of vegetation were obtained for a period of 5 years. The main results show that: (1) the proposed predictive model provides reliable and resilient soil water estimates under a wide range of external conditions; (2) the predicted soil water storage and the error bounds provided by the model offer a realistic and rational basis for decisions such as when to curtail well field operation to ensure plant survival. The predictive model offers a practical means for accommodating simple aspects of spatial variability by considering the additional source of uncertainty as part of modeling or measurement uncertainty.

  11. Estimating steady-state evaporation rates from bare soils under conditions of high water table

    Science.gov (United States)

    Ripple, C.D.; Rubin, J.; Van Hylckama, T. E. A.

    1970-01-01

    A procedure that combines meteorological and soil equations of water transfer makes it possible to estimate approximately the steady-state evaporation from bare soils under conditions of high water table. Field data required include soil-water retention curves, water table depth and a record of air temperature, air humidity and wind velocity at one elevation. The procedure takes into account the relevant atmospheric factors and the soil's capability to conduct 'water in liquid and vapor forms. It neglects the effects of thermal transfer (except in the vapor case) and of salt accumulation. Homogeneous as well as layered soils can be treated. Results obtained with the method demonstrate how the soil evaporation rates·depend on potential evaporation, water table depth, vapor transfer and certain soil parameters.

  12. Geostatistical investigation into the temporal evolution of spatial structure in a shallow water table

    Directory of Open Access Journals (Sweden)

    S. W. Lyon

    2006-01-01

    Full Text Available Shallow water tables near-streams often lead to saturated, overland flow generating areas in catchments in humid climates. While these saturated areas are assumed to be principal biogeochemical hot-spots and important for issues such as non-point pollution sources, the spatial and temporal behavior of shallow water tables, and associated saturated areas, is not completely understood. This study demonstrates how geostatistical methods can be used to characterize the spatial and temporal variation of the shallow water table for the near-stream region. Event-based and seasonal changes in the spatial structure of the shallow water table, which influences the spatial pattern of surface saturation and related runoff generation, can be identified and used in conjunction to characterize the hydrology of an area. This is accomplished through semivariogram analysis and indicator kriging to produce maps combining soft data (i.e., proxy information to the variable of interest representing general shallow water table patterns with hard data (i.e., actual measurements that represent variation in the spatial structure of the shallow water table per rainfall event. The area used was a hillslope in the Catskill Mountains region of New York State. The shallow water table was monitored for a 120 m×180 m near-stream region at 44 sampling locations on 15-min intervals. Outflow of the area was measured at the same time interval. These data were analyzed at a short time interval (15 min and at a long time interval (months to characterize the changes in the hydrologic behavior of the hillslope. Indicator semivariograms based on binary-transformed ground water table data (i.e., 1 if exceeding the time-variable median depth to water table and 0 if not were created for both short and long time intervals. For the short time interval, the indicator semivariograms showed a high degree of spatial structure in the shallow water table for the spring, with increased range

  13. Study on the breakwater caisson as oscillating water column facility

    Science.gov (United States)

    Huang, Yan; Shi, Hongda; Liu, Defu; Liu, Zhen

    2010-09-01

    The Oscillating Water Column (OWC) wave energy convertor with the advantage of its simple geometrical construction and excellent stability is widely employed. Recently, perforated breakwaters have been often used as they can effectively reduce the wave reflection from and wave forces acting on the structures. Considering the similarity between the compartment of perforated caisson and the air chamber of OWC wave energy convertor, a new perforated caisson of breakwater is designed in this paper. The ordinary caisson is modified by installing facilities similar to the air chamber of OWC converter, but here they are utilized to dissipate the wave energy inside the caisson. Such an arrangement improves the stability of the caisson and reduces the construction cost by using the compartment of perforated caisson like using an air chamber. This innovation has both academic significance and important engineering value. For a new type of caisson, reliability analysis of the structure is necessary. Linear potential flow theory is applied to calculate the horizontal wave force acting on the caisson. The calculated results are compared with experimental data, showing the feasibility of the method. The Importance Sampling Procedure (ISP) is used to analyse the reliability of this caisson breakwater.

  14. Power oscillation and stability in water cooled reactors

    International Nuclear Information System (INIS)

    Por, G.; Kis, G.

    1998-01-01

    Periodic oscillation in measured temperature fluctuation was observed near to surface of a heated rod in certain heat transfer range. The frequency of the peak found in power spectral density of temperature fluctuation and period estimated from the cross correlation function for two axially placed thermocouples change linearly with linear energy (or surface heat) production. It was concluded that a resonance of such surface (inlet) temperature oscillation with the pole of the reactor transfer function can be responsible for power oscillation in BWR and PWR, thus instability is not solely due to reactor transfer function. (author)

  15. Tight Coupling of Metabolic Oscillations and Intracellular Water Dynamics in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Thoke, Henrik Seir; Tobiesen, Asger; Brewer, Jonathan R.

    2015-01-01

    We detected very strong coupling between the oscillating concentration of ATP and the dynamics of intracellular water during glycolysis in Saccharomyces cerevisiae. Our results indicate that: i) dipolar relaxation of intracellular water is heterogeneous within the cell and different from dilute...... conditions, ii) water dipolar relaxation oscillates with glycolysis and in phase with ATP concentration, iii) this phenomenon is scale-invariant from the subcellular to the ensemble of synchronized cells and, iv) the periodicity of both glycolytic oscillations and dipolar relaxation are equally affected by D...

  16. Influence of the tension-saturated zone on contaminant migration in shallow water-table regimes

    International Nuclear Information System (INIS)

    Gillham, R.W.

    1982-01-01

    Groundwater discharge represents a major pathway for the return to the biosphere of contaminants that are released to the subsurface environment. An understanding of the transport processes in groundwater discharge zones is therefore an important consideration in pathway analyses associated with the environmental assessment of proposed waste-management facilities. Shallow water tables are a common characteristic of groundwater discharge zones, particularly in humid climatic regions. In this paper, the results of field tests, laboratory tests and numerical simulations are used to show that under shallow water-table conditions, the zone of tension saturation can result in a rapid and highly disproportionate water-table response to precipitation. It is further shown that this response can result in complex migration patterns that would not be predicted by the classical approaches to solute transport modelling and that the response could result in large and highly transient inputs to surface water

  17. An oscillation phenomenon of low frequency reverberation in the shallow water and its physical explanation

    Institute of Scientific and Technical Information of China (English)

    LI; Fenghua; LIU; Jianjun; LI; Zhenglin; ZHANG; Renhe

    2005-01-01

    An oscillation phenomenon of the low frequency reverberation intensity was observed in several shallow water reverberation experiments. This phenomenon cannot be explained by the widely used incoherent reverberation theory. In this paper, to explain the observed oscillation phenomenon, a normal mode based coherent reverberation theory is presented. The theoretical analysis and numerical results show that modal interference can cause the regular oscillation phenomenon of the low frequency reverberation intensity, and the oscillation frequency is determined by the normal mode eigen-values. A new method to estimate the bottom sound speed based on the oscillation frequency of reverberation intensity was presented in this paper. The experimental results at three different sites indicate that the bottom sound speed estimated from the oscillation frequency of reverberation intensity agrees with that inverted from Matched Field Processing (MFP) well.

  18. Water laws in eleven midwestern states: summary tables

    Energy Technology Data Exchange (ETDEWEB)

    McNeil, T.L.; Torpy, M.F.

    1979-06-01

    Basic information about the water laws of Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Ohio, and West Virginia is summarized. References to state laws and court decisions that may be useful in assessing the legal availability of water for energy development are provided. (MCW)

  19. Energy balance concept in the evaluation of water table management effects on corn growth: experimental investigation

    International Nuclear Information System (INIS)

    Kalita, P.K.; Kanwar, R.S.

    1992-01-01

    The effects of water table management practices (WTMP) on corn growth in 1989 and 1990 at two field sites, Ames and Ankeny, Iowa, were evaluated by calculating crop water stress index (CWSI) and monitoring plant physiological parameters during the growing seasons. Experiments were conducted on field lysimeters at the Ames site by maintaining water tables at 0.3-, 0.6-, and 0.9-m depths and in a subirrigation field at the Ankeny site with 0.2-, 0.3-, 0.6-, 0.9-, and 1.1-m water table depths, and periodically measuring leaf and air temperature, transpiration rate, stomatal conductance, and photosynthetically active radiation (PAR) using leaf chamber techniques. Net radiation of canopy was estimated using the leaf energy balance equation and leaf chamber measurements and then correlated with PAR. Analysis of data revealed that net radiation, leaf air temperature differential, transpiration rate, stomatal conductance, and CWSI were strongly related to WTMP during vegetative and flowering stages of corn growth. Excess water in the root zone with a water table depth of 0.2 m caused the maximum crop water stress and ceased crop growth. Both water and oxygen could be adequately maintained for favorable crop growth by adopting the best WTMP. Results indicate that plant physiological parameters and CWSI could be used to evaluate the effectiveness of WTMP and develop the best WTMP for corn growth in the humid region

  20. Model evaluation of seepage from uranium tailings disposal above and below the water table

    International Nuclear Information System (INIS)

    Nelson, R.W.; Meyer, P.R.; Oberlander, P.L.; Sneider, S.C.; Mayer, D.W.; Reisenauer, A.E.

    1983-03-01

    Model simulations identify the rate and amount of leachate released to the environment if disposed uranium mill tailings come into contact with ground water or if seepage from tailings reaches ground water. In this study, simulations of disposal above and below the water table, with various methods of leachate control, were compared. Three leachate control methods were used in the comparisons: clay bottom liners; stub-sidewall clay liners; and tailings drains with sumps, with the effluent pumped back from the sumps. The best leachate control for both above and below the water table is a combination of the three methods. The combined methods intercept up to 80% of the leachate volume in pits above the water table and intercept essentially all of the leachate in pits below the water table. Effluent pumping, however, requires continuous energy costs and an alternative method of disposal for the leachate that cannot be reused as makeup water in the mill process. Without the drains or effluent pumping, the clay bottom liners have little advantage in terms of the total volume of leachate lost. The clay liners do reduce the rate of leachate flow to the ground water, but the flow continues for a longer time. The buffering, sorption, and chemical reactions of the leachate passing directly through the liner are also advantages of the liner

  1. Preliminary Water-Table Map and Water-Quality Data for Part of the Matanuska-Susitna Valley, Alaska, 2005

    Science.gov (United States)

    Moran, Edward H.; Solin, Gary L.

    2006-01-01

    The Matanuska-Susitna Valley is in the northeastern part of the Cook Inlet Basin, Alaska, an area experiencing rapid population growth and development proximal to many lakes. Here water commonly flows between lakes and ground water, indicating interrelation between water quantity and quality. Thus concerns exist that poorer quality ground water may degrade local lake ecosystems. This concern has led to water-quality sampling in cooperation with the Alaska Department of Environmental Conservation and the Matanuska-Susitna Borough. A map showing the estimated altitude of the water table illustrates potential ground-water flow directions and areas where ground- and surface-water exchanges and interactions might occur. Water quality measured in selected wells and lakes indicates some differences between ground water and surface water. 'The temporal and spatial scarcity of ground-water-level and water-quality data limits the analysis of flow direction and water quality. Regionally, the water-table map indicates that ground water in the eastern and southern parts of the study area flows southerly. In the northcentral area, ground water flows predominately westerly then southerly. Although ground and surface water in most areas of the Matanuska-Susitna Valley are interconnected, they are chemically different. Analyses of the few water-quality samples collected in the area indicate that dissolved nitrite plus nitrate and orthophosphorus concentrations are higher in ground water than in surface water.'

  2. Conversion of thermall energy to mechanical work in the oscillations with steam condensation in pool water

    International Nuclear Information System (INIS)

    Aya, Izuo; Nariai, Hideki.

    1988-01-01

    Pressure and fluid oscillations with steam injection into pool water were discussed from the view point of the conversion of thermal energy into mechanical work. When the change of fluid state moves clockwise in the p-V diagram, the oscillation sustains since the thermal energy changes into positive work. The equations difining the mechanical work at the condensation oscillations were presented. The oscillation threshold determined by the condition that mechanical work became zero, coincided with the values derived by the linear oscillation theory. The changes of pressure and specific volume during chugging were also shown with one dimensional simulation analysis. The p-V diagrams at various chugging modes were presented with the movement of steam water interface, and the conversion efficiency of thermal energy to mechanical work was also discussed. (author)

  3. Combined uses of water-table fluctuation (WTF), chloride mass ...

    African Journals Online (AJOL)

    Agadaga

    isotopes methods to investigate groundwater recharge ... and isotopic characterization of groundwater, rainfall and the unsaturated zone were also carried out using a ..... Chloride concentrations in soil water extracted by lixiviation from.

  4. Environmental isotope profiles and evaporation in shallow water table soils

    International Nuclear Information System (INIS)

    Hussein, M.F.; Froehlich, K.; Nada, A.

    2001-01-01

    Environmental isotope methods have been employed to evaluate the processes of evaporation and soil salinisation in the Nile Delta. Stable isotope profiles (δ 18 O and δ 2 H) from three sites were analysed using a published isothermal model that analyses the steady-state isotopic profile in the unsaturated zone and provides an estimate of the evaporation rate. Evaporation rates estimated by this method at the three sites range between 60 and 98 mm y -1 which translates to an estimate of net water loss of one billion cubic meters per year from fallow soils on the Nile delta. Capillary rise of water through the root zone during the crop growing season is estimated to be three times greater than evaporation rate estimate and a modified water management strategy could be adopted in order to optimize water use and its management on the regional scale. (author)

  5. Radar sounding of bedrock and water table at Chalk River

    International Nuclear Information System (INIS)

    Annan, A.P.; Davis, J.L.

    1979-01-01

    When a spill of radioactive waste occurs, one of the main concerns is the flow pattern of ground water in the area of the spill. Ground probing radar is a relatively new geophysical technique which can provide high resolution data on the surficial geology and water distribution. The results of some preliminary radar experiments conducted at Chalk River Nuclear Laboratories (CRNL) of the Atomic Energy of Canada Limited (AECL), Chalk River, Ontario are presented. (auth)

  6. Water table lowering to improve excavation performance and to reduce acid mine drainage

    International Nuclear Information System (INIS)

    Koppe, J.C.; Costa, J.F.; Laurent, O. Jr.

    1995-01-01

    This paper analyses the water table level fluctuations using wells located adjacent to the stripping cuts at the Butia-Leste coal mine, southernmost of Brazil. Piezometers monitored the water table fluctuations. Geological mapping provided additional information aiding the interpretation of the results. A contouring software was also used as tool to aid the interpretation of the data and the results visualisation. The parameters necessary in selecting the location of the wells and pumping volumes were calculated from the data obtained in the water table lowering tests. The results were used to minimise two main problems: the generation of acid mine drainage and the reduction of the excavation performance of the fleet used in overburden removal. 7 refs., 5 figs., 3 tabs

  7. Water tables constrain height recovery of willow on Yellowstone's northern range.

    Science.gov (United States)

    Bilyeu, Danielle M; Cooper, David J; Hobbs, N Thompson

    2008-01-01

    Excessive levels of herbivory may disturb ecosystems in ways that persist even when herbivory is moderated. These persistent changes may complicate efforts to restore ecosystems affected by herbivores. Willow (Salix spp.) communities within the northern range in Yellowstone National Park have been eliminated or degraded in many riparian areas by excessive elk (Cervus elaphus L.) browsing. Elk browsing of riparian willows appears to have diminished following the reintroduction of wolves (Canis lupis L.), but it remains uncertain whether reduced herbivory will restore willow communities. The direct effects of elk browsing on willows have been accompanied by indirect effects from the loss of beaver (Castor canadensis Kuhl) activity, including incision of stream channels, erosion of fine sediments, and lower water tables near streams historically dammed by beaver. In areas where these changes have occurred, lowered water tables may suppress willow height even in the absence of elk browsing. We conducted a factorial field experiment to understand willow responses to browsing and to height of water tables. After four years of protection from elk browsing, willows with ambient water tables averaged only 106 cm in height, with negligible height gain in two of three study species during the last year of the experiment. Willows that were protected from browsing and had artificially elevated water tables averaged 147 cm in height and gained 19 cm in the last year of the experiment. In browsed plots, elevated water tables doubled height gain during a period of slightly reduced browsing pressure. We conclude that water availability mediates the rate of willow height gain and may determine whether willows grow tall enough to escape the browse zone of elk and gain resistance to future elk browsing. Consequently, in areas where long-term beaver absence has resulted in incised stream channels and low water tables, a reduction in elk browsing alone may not be sufficient for recovery

  8. Estimating drain flow from measured water table depth in layered soils under free and controlled drainage

    Science.gov (United States)

    Saadat, Samaneh; Bowling, Laura; Frankenberger, Jane; Kladivko, Eileen

    2018-01-01

    Long records of continuous drain flow are important for quantifying annual and seasonal changes in the subsurface drainage flow from drained agricultural land. Missing data due to equipment malfunction and other challenges have limited conclusions that can be made about annual flow and thus nutrient loads from field studies, including assessments of the effect of controlled drainage. Water table depth data may be available during gaps in flow data, providing a basis for filling missing drain flow data; therefore, the overall goal of this study was to examine the potential to estimate drain flow using water table observations. The objectives were to evaluate how the shape of the relationship between drain flow and water table height above drain varies depending on the soil hydraulic conductivity profile, to quantify how well the Hooghoudt equation represented the water table-drain flow relationship in five years of measured data at the Davis Purdue Agricultural Center (DPAC), and to determine the impact of controlled drainage on drain flow using the filled dataset. The shape of the drain flow-water table height relationship was found to depend on the selected hydraulic conductivity profile. Estimated drain flow using the Hooghoudt equation with measured water table height for both free draining and controlled periods compared well to observed flow with Nash-Sutcliffe Efficiency values above 0.7 and 0.8 for calibration and validation periods, respectively. Using this method, together with linear regression for the remaining gaps, a long-term drain flow record for a controlled drainage experiment at the DPAC was used to evaluate the impacts of controlled drainage on drain flow. In the controlled drainage sites, annual flow was 14-49% lower than free drainage.

  9. Influence of water table decline on growth allocation and endogenous gibberellins in black cottonwood

    Energy Technology Data Exchange (ETDEWEB)

    Rood, S.B.; Zanewich, K.; Stefura, C. [Lethbridge Univ., Lethbridge, AB (Canada). Dept. of Biological Sciences; Mahoney, J.M. [Alberta Environmental Protection, Lethbridge, AB (Canada)

    2000-06-01

    Cottonwoods have shown an adaptation to the riparian zone by coordinating root elongation to maintain contact with the water table, whose depth varies with the elevation of the adjacent river. The rate of water decline on growth allocation and concentrations of endogenous gibberellins (GAs) in black cottonwood saplings were studied at the University of Lethbridge, Alberta. Water declines were achieved by using rhizopods, and root elongation approximately doubled in response whereas leaf area was reduced. At some point, a greater water decline rate led to water stress resulting in reduced growth, increased leaf diffusive resistance, decreased water potential, and leaf senescence and abscission. After extraction of endogenous GAs, they were purified and analysed by gas chromatography-selected ion monitoring with internal ({sup 2}H{sub 2})GA standards. The results showed that GAs were higher in shoot tips and sequentially lower in basal stems, root tips, leaves and upper roots. Noticeable relationships did not appear between GA concentration and growth allocation across the water decline treatments. Only GA{sub 8} showed a consistent reduction in plants experiencing water table decline. This research did not permit the authors to conclude whether endogenous GAs play a primary role in the regulation of root elongation in response to water table decline. 7 figs., 25 refs.

  10. Forced convective boiling of water inside helically coiled tube. Characteristics of oscillation of dryout point

    International Nuclear Information System (INIS)

    Nagai, Niro; Sugiyama, Kenta; Takeuchi, Masanori; Yoshikawa, Shinji; Yamamoto, Fujio

    2006-01-01

    The helically coiled tube of heat exchanger is used for the evaporator of prototype fast breeder reactor 'Monju'. This paper aims at the grasp of two-phase flow phenomena of forced convective boiling of water inside helical coiled tube, especially focusing on oscillation phenomena of dryout point. A glass-made helically coiled tube was used to observe the inside water boiling behavior flowing upward, which was heated by high temperature oil outside the tube. This oil was also circulated through a glass made tank to provide the heat source for water evaporation. The criterion for oscillation of dryout point was found to be a function of inlet liquid velocity and hot oil temperature. The observation results suggest the mechanism of dryout point oscillation mainly consists of intensive nucleate boiling near the dryout point and evaporation of thin liquid film flowing along the helical tube. In addition, the oscillation characteristics were experimentally confirmed. As inlet liquid velocity increases, oscillation amplitude also increases but oscillation cycle does not change so much. As hot oil temperature increases, oscillation amplitude and cycle gradually decreases. (author)

  11. Effect of water table fluctuations on phreatophytic root distribution.

    Science.gov (United States)

    Tron, Stefania; Laio, Francesco; Ridolfi, Luca

    2014-11-07

    The vertical root distribution of riparian vegetation plays a relevant role in soil water balance, in the partition of water fluxes into evaporation and transpiration, in the biogeochemistry of hyporheic corridors, in river morphodynamics evolution, and in bioengineering applications. The aim of this work is to assess the effect of the stochastic variability of the river level on the root distribution of phreatophytic plants. A function describing the vertical root profile has been analytically obtained by coupling a white shot noise representation of the river level variability to a description of the dynamics of root growth and decay. The root profile depends on easily determined parameters, linked to stream dynamics, vegetation and soil characteristics. The riparian vegetation of a river characterized by a high variability turns out to have a rooting system spread over larger depths, but with shallower mean root depths. In contrast, a lower river variability determines root profiles with higher mean root depths. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Water table in Long Island, New York, March 1971

    Science.gov (United States)

    Koszalka, Edward J.; Koch, Ellis

    1971-01-01

    The geologic framework and the hydrologic situation in Long Island are periodically reviewed by the U.S. Geological Survey as new knowledge is obtained from current investigations. This work is done through cooperative programs with Nassau and Suffolk County agencies and the New York State Department of Environmental Conservation. A unique opportunity to update many of the hydrogeologic maps occurred when the Geological Survey's Mineola, N.Y., office participated in the New England River Basins Commission's "Long Island Sound Study." This map, one of a series of open-file maps showing the updated information, was compiled from data obtained from G. E. Kimmel (written commun., July 1972) and Jensen and Soren (in press). Comparison of the March 1971 data with similar data for March 1970 (Kimmel, 1970) shows virtually no change in water levels on Long Island during the 12 month period, except for a slight decline in levels in central Suffolk County.

  13. Modeling caspian sea water level oscilLations Under Diffrent Scenarioes of Increasing Atmospheric Carbon Dioxide Concentrations

    Directory of Open Access Journals (Sweden)

    GholamReza Roshan

    2012-12-01

    Full Text Available The rapid rise of Caspian Sea water level (about 2.25 meters since 1978 has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in thecoastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was stimulated. Variations in environmentalparameters such as temperature, precipitation, evaporation, tmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for bothpast (1951-2006 and future (2025-2100 time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software(version 5.3. The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site has increased by ca. 0.17ºC per decade under the impacts of atmospheric carbon dioxide changes (r=0.21. The Caspian Sea water level has increasedby ca. +36 mm per decade (r=0.82 between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64ºC and precipitation will decrease by ca. 10% (182 mm over the Caspian Sea, whilst in the Volga river basin,temperatures are projected to increase by ca. 4.78ºC and precipitation increase by ca. 12% (58 mm by the year 2100. Finally, statistical modeling of the Caspian Sea water levels projectfuture water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

  14. Measurement of the 226Ra-concentration in bottled Austrian mineral waters and table beverages

    International Nuclear Information System (INIS)

    Friedmann, H.; Hernegger, F.

    1978-01-01

    226 Ra being regarded nowadays as a toxic trace element, a systementic examination of bottled Austrian mineral waters and table beverages has been carried out. Only in one case was the maximum allowable concentration of 3.3 pCi/l, a value set up by the WHO, clearly exceeded. (orig.) [de

  15. Accuracy of spatio-temporal RARX model predictions of water table depths

    NARCIS (Netherlands)

    Knotters, M.; Bierkens, M.F.P.

    2002-01-01

    Time series of water table depths (Ht) are predicted in space using a regionalised autoregressive exogenous variable (RARX) model with precipitation surplus (Pt) as input variable. Because of their physical basis, RARX model parameters can be guessed from auxiliary information such as a digital

  16. Response of anaerobic carbon cycling to water table manipulation in an Alaskan rich fen

    Science.gov (United States)

    Kane, E.S.; Chivers, M.R.; Turetsky, M.R.; Treat, C.C.; Petersen, D.G.; Waldrop, M.; Harden, J.W.; McGuire, A.D.

    2013-01-01

    To test the effects of altered hydrology on organic soil decomposition, we investigated CO2 and CH4 production potential of rich-fen peat (mean surface pH = 6.3) collected from a field water table manipulation experiment including control, raised and lowered water table treatments. Mean anaerobic CO2 production potential at 10 cm depth (14.1 ± 0.9 μmol C g−1 d−1) was as high as aerobic CO2 production potential (10.6 ± 1.5 μmol C g−1 d−1), while CH4 production was low (mean of 7.8 ± 1.5 nmol C g−1 d−1). Denitrification enzyme activity indicated a very high denitrification potential (197 ± 23 μg N g−1 d−1), but net NO-3 reduction suggested this was a relatively minor pathway for anaerobic CO2 production. Abundances of denitrifier genes (nirK and nosZ) did not change across water table treatments. SO2-4 reduction also did not appear to be an important pathway for anaerobic CO2 production. The net accumulation of acetate and formate as decomposition end products in the raised water table treatment suggested that fermentation was a significant pathway for carbon mineralization, even in the presence of NO-3. Dissolved organic carbon (DOC) concentrations were the strongest predictors of potential anaerobic and aerobic CO2 production. Across all water table treatments, the CO2:CH4 ratio increased with initial DOC leachate concentrations. While the field water table treatment did not have a significant effect on mean CO2 or CH4 production potential, the CO2:CH4 ratio was highest in shallow peat incubations from the drained treatment. These data suggest that with continued drying or with a more variable water table, anaerobic CO2 production may be favored over CH4 production in this rich fen. Future research examining the potential for dissolved organic substances to facilitate anaerobic respiration, or alternative redox processes that limit the effectiveness of organic acids as substrates in anaerobic metabolism, would help explain additional

  17. Reducing nitrate loss in tile drainage water with cover crops and water-table management systems.

    Science.gov (United States)

    Drury, C F; Tan, C S; Welacky, T W; Reynolds, W D; Zhang, T Q; Oloya, T O; McLaughlin, N B; Gaynor, J D

    2014-03-01

    Nitrate lost from agricultural soils is an economic cost to producers, an environmental concern when it enters rivers and lakes, and a health risk when it enters wells and aquifers used for drinking water. Planting a winter wheat cover crop (CC) and/or use of controlled tile drainage-subirrigation (CDS) may reduce losses of nitrate (NO) relative to no cover crop (NCC) and/or traditional unrestricted tile drainage (UTD). A 6-yr (1999-2005) corn-soybean study was conducted to determine the effectiveness of CC+CDS, CC+UTD, NCC+CDS, and NCC+UTD treatments for reducing NO loss. Flow volume and NO concentration in surface runoff and tile drainage were measured continuously, and CC reduced the 5-yr flow-weighted mean (FWM) NO concentration in tile drainage water by 21 to 38% and cumulative NO loss by 14 to 16% relative to NCC. Controlled tile drainage-subirrigation reduced FWM NO concentration by 15 to 33% and cumulative NO loss by 38 to 39% relative to UTD. When CC and CDS were combined, 5-yr cumulative FWM NO concentrations and loss in tile drainage were decreased by 47% (from 9.45 to 4.99 mg N L and from 102 to 53.6 kg N ha) relative to NCC+UTD. The reductions in runoff and concomitant increases in tile drainage under CC occurred primarily because of increases in near-surface soil hydraulic conductivity. Cover crops increased corn grain yields by 4 to 7% in 2004 increased 3-yr average soybean yields by 8 to 15%, whereas CDS did not affect corn or soybean yields over the 6 yr. The combined use of a cover crop and water-table management system was highly effective for reducing NO loss from cool, humid agricultural soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  18. Ground Water Recharge Estimation Using Water Table Fluctuation Method And By GIS Applications

    Science.gov (United States)

    Vajja, V.; Bekkam, V.; Nune, R.; M. v. S, R.

    2007-05-01

    Quite often it has become a debating point that how much recharge is occurring to the groundwater table through rainfall on one hand and through recharge structures such as percolation ponds and checkdams on the other. In the present investigations Musi basin of Andhra Pradesh, India is selected for study during the period 2005-06. Pre-monsoon and Post-monsoon groundwater levels are collected through out the Musi basin at 89 locations covering an area11, 291.69 km2. Geology of the study area and rainfall data during the study period has been collected. The contour maps of rainfall and the change in groundwater level between Pre-monsoon and Post- monsoon have been prepared. First the change in groundwater storage is estimated for each successive strips of areas enclosed between two contours of groundwater level fluctuations. In this calculation Specific yield (Sy) values are adopted based on the local Geology. Areas between the contours are estimated through Arc GIS software package. All such storages are added to compute the total storage for the entire basin. In order to find out the percent of rainfall converted into groundwater storage as well as to find out the ground water recharge due to storageponds, a contour map of rainfall for the study area is prepared and areas between successive contours have been calculated. Based on the Geology map, Infiltration values are adopted for each successive strip of the contour area. Then the amount of water infiltrated into the ground is calculated by adjusting the infiltration values for each strip, so that the total infiltrated water for the entire basin is matched with change in Ground water storage, which is 1314.37 MCM for the upper Musi basin while it is 2827.29 MCM for entire Musi basin. With this procedure on an average 29.68 and 30.66 percent of Rainfall is converted into Groundwater recharge for Upper Musi and for entire Musi basin respectively. In the total recharge, the contribution of rainfall directly to

  19. Regional water table (2016) in the Mojave River and Morongo groundwater basins, southwestern Mojave Desert, California

    Science.gov (United States)

    Dick, Meghan; Kjos, Adam

    2017-12-07

    From January to April 2016, the U.S. Geological Survey (USGS), the Mojave Water Agency, and other local water districts made approximately 1,200 water-level measurements in about 645 wells located within 15 separate groundwater basins, collectively referred to as the Mojave River and Morongo groundwater basins. These data document recent conditions and, when compared with older data, changes in groundwater levels. A water-level contour map was drawn using data measured in 2016 that shows the elevation of the water table and general direction of groundwater movement for most of the groundwater basins. Historical water-level data stored in the USGS National Water Information System (https://waterdata.usgs.gov/nwis/) database were used in conjunction with data collected for this study to construct 37 hydrographs to show long-term (1930–2016) and short-term (1990–2016) water-level changes in the study area.

  20. Risk evaluation of ground water table decline as a type of desertification. A case study are: Southern Iran

    Energy Technology Data Exchange (ETDEWEB)

    Asrari, E.; Masoudi, M.

    2009-07-01

    This paper presents a model to assess risk of ground water table decline. Taking into consideration eleven indicators of lowering of ground water table the model identifies areas with Potential Risk (risky zones) and areas of Actual risk as well as projects the probability of the worse degradation in future. (Author) 7 refs.

  1. Risk evaluation of ground water table decline as a type of desertification. A case study are: Southern Iran

    International Nuclear Information System (INIS)

    Asrari, E.; Masoudi, M.

    2009-01-01

    This paper presents a model to assess risk of ground water table decline. Taking into consideration eleven indicators of lowering of ground water table the model identifies areas with Potential Risk (risky zones) and areas of Actual risk as well as projects the probability of the worse degradation in future. (Author) 7 refs.

  2. Sensitivity of stream flow and water table depth to potential climatic variability in a coastal forested watershed

    Science.gov (United States)

    Zhaohua Dai; Carl Trettin; Changsheng Li; Devendra M. Amatya; Ge Sun; Harbin Li

    2010-01-01

    A physically based distributed hydrological model, MIKE SHE, was used to evaluate the effects of altered temperature and precipitation regimes on the streamflow and water table in a forested watershed on the southeastern Atlantic coastal plain. The model calibration and validation against both streamflow and water table depth showed that the MIKE SHE was applicable for...

  3. Controlled laboratory experiments and modeling of vegetative filter strips with shallow water tables

    Science.gov (United States)

    Fox, Garey A.; Muñoz-Carpena, Rafael; Purvis, Rebecca A.

    2018-01-01

    Natural or planted vegetation at the edge of fields or adjacent to streams, also known as vegetative filter strips (VFS), are commonly used as an environmental mitigation practice for runoff pollution and agrochemical spray drift. The VFS position in lowlands near water bodies often implies the presence of a seasonal shallow water table (WT). In spite of its potential importance, there is limited experimental work that systematically studies the effect of shallow WTs on VFS efficacy. Previous research recently coupled a new physically based algorithm describing infiltration into soils bounded by a water table into the VFS numerical overland flow and transport model, VFSMOD, to simulate VFS dynamics under shallow WT conditions. In this study, we tested the performance of the model against laboratory mesoscale data under controlled conditions. A laboratory soil box (1.0 m wide, 2.0 m long, and 0.7 m deep) was used to simulate a VFS and quantify the influence of shallow WTs on runoff. Experiments included planted Bermuda grass on repacked silt loam and sandy loam soils. A series of experiments were performed including a free drainage case (no WT) and a static shallow water table (0.3-0.4 m below ground surface). For each soil type, this research first calibrated VFSMOD to the observed outflow hydrograph for the free drainage experiments to parameterize the soil hydraulic and vegetation parameters, and then evaluated the model based on outflow hydrographs for the shallow WT experiments. This research used several statistical metrics and a new approach based on hypothesis testing of the Nash-Sutcliffe model efficiency coefficient (NSE) to evaluate model performance. The new VFSMOD routines successfully simulated the outflow hydrographs under both free drainage and shallow WT conditions. Statistical metrics considered the model performance valid with greater than 99.5% probability across all scenarios. This research also simulated the shallow water table experiments with

  4. Simulation of upward flux from shallow water-table using UPFLOW model

    Directory of Open Access Journals (Sweden)

    M. H. Ali

    2013-11-01

    Full Text Available The upward movement of water by capillary rise from shallow water-table to the root zone is an important incoming flux. For determining exact amount of irrigation requirement, estimation of capillary flux or upward flux is essential. Simulation model can provide a reliable estimate of upward flux under variable soil and climatic conditions. In this study, the performance of model UPFLOW to estimate upward flux was evaluated. Evaluation of model performance was performed with both graphical display and statistical criteria. In distribution of simulated capillary rise values against observed field data, maximum data points lie around the 1:1 line, which means that the model output is reliable and reasonable. The coefficient of determination between observed and simulated values was 0.806 (r = 0.93, which indicates a good inter-relation between observed and simulated values. The relative error, model efficiency, and index of agreement were found as 27.91%, 85.93% and 0.96, respectively. Considering the graphical display of observed and simulated upward flux and statistical indicators, it can be concluded that the overall performance of the UPFLOW model in simulating actual upward flux from a crop field under variable water-table condition is satisfactory. Thus, the model can be used to estimate capillary rise from shallow water-table for proper estimation of irrigation requirement, which would save valuable water from over-irrigation.

  5. Non normal modal analysis of oscillations in boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Suarez-Antola, Roberto, E-mail: roberto.suarez@miem.gub.uy [Ministerio de Industria, Energia y Mineria (MIEM), Montevideo (Uruguay); Flores-Godoy, Jose-Job, E-mail: job.flores@ibero.mx [Universidad Iberoamericana (UIA), Mexico, DF (Mexico). Dept. de Fisica Y Matematicas

    2013-07-01

    The first objective of the present work is to construct a simple reduced order model for BWR stability analysis, combining a two nodes nodal model of the thermal hydraulics with a two modes modal model of the neutronics. Two coupled non-linear integral-differential equations are obtained, in terms of one global (in phase) and one local (out of phase) power amplitude, with direct and cross feedback reactivities given as functions of thermal hydraulics core variables (void fractions and temperatures). The second objective is to apply the effective life time approximation to further simplify the nonlinear equations. Linear approximations for the equations of the amplitudes of the global and regional modes are derived. The linearized equation for the amplitude of the global mode corresponds to a decoupled and damped harmonic oscillator. An analytical closed form formula for the damping coefficient, as a function of the parameters space of the BWR, is obtained. The coefficient changes its sign (with the corresponding modification in the decay ratio) when a stability boundary is crossed. This produces a supercritical Hopf bifurcation, with the steady state power of the reactor as the bifurcation parameter. However, the linearized equation for the amplitude of the regional mode corresponds always to an over-damped and always coupled (with the amplitude of the global mode) harmonic oscillator, for every set of possible values of core parameters (including the steady state power of the reactor) in the framework of the present mathematical model. The equation for the above mentioned over damped linear oscillator is closely connected with a non-normal operator. Due to this connection, there could be a significant transient growth of some solutions of the linear equation. This behavior allows a significant shrinking of the basin of attraction of the equilibrium state. The third objective is to apply the above approach to partially study the stability of the regional mode and

  6. Modelling contrasting responses of wetland productivity to changes in water table depth

    Directory of Open Access Journals (Sweden)

    R. F. Grant

    2012-11-01

    Full Text Available Responses of wetland productivity to changes in water table depth (WTD are controlled by complex interactions among several soil and plant processes, and hence are site-specific rather than general in nature. Hydrological controls on wetland productivity were studied by representing these interactions in connected hummock and hollow sites in the ecosystem model ecosys, and by testing CO2 and energy fluxes from the model with those measured by eddy covariance (EC during years with contrasting WTD in a shrub fen at Lost Creek, WI. Modelled interactions among coupled processes for O2 transfer, O2 uptake, C oxidation, N mineralization, N uptake and C fixation by diverse microbial, root and mycorrhizal populations enabled the model to simulate complex responses of CO2 exchange to changes in WTD that depended on the WTD at which change was occurring. At the site scale, greater WTD caused the model to simulate greater CO2 influxes and effluxes over hummocks vs. hollows, as has been found at field sites. At the landscape scale, greater WTD caused the model to simulate greater diurnal CO2 influxes and effluxes under cooler weather when water tables were shallow, but also smaller diurnal CO2 influxes and effluxes under warmer weather when water tables were deeper, as was also apparent in the EC flux measurements. At an annual time scale, these diurnal responses to WTD in the model caused lower net primary productivity (NPP and heterotrophic respiration (Rh, but higher net ecosystem productivity (NEP = NPP − Rh, to be simulated in a cooler year with a shallower water table than in a warmer year with a deeper one. This difference in NEP was consistent with those estimated from gap-filled EC fluxes in years with different water tables at Lost Creek and at similar boreal fens elsewhere. In sensitivity tests of the model, annual NEP

  7. Increasing the utility of regional water table maps: a new method for estimating groundwater recharge

    Science.gov (United States)

    Gilmore, T. E.; Zlotnik, V. A.; Johnson, M.

    2017-12-01

    Groundwater table elevations are one of the most fundamental measurements used to characterize unconfined aquifers, groundwater flow patterns, and aquifer sustainability over time. In this study, we developed an analytical model that relies on analysis of groundwater elevation contour (equipotential) shape, aquifer transmissivity, and streambed gradient between two parallel, perennial streams. Using two existing regional water table maps, created at different times using different methods, our analysis of groundwater elevation contours, transmissivity and streambed gradient produced groundwater recharge rates (42-218 mm yr-1) that were consistent with previous independent recharge estimates from different methods. The three regions we investigated overly the High Plains Aquifer in Nebraska and included some areas where groundwater is used for irrigation. The three regions ranged from 1,500 to 3,300 km2, with either Sand Hills surficial geology, or Sand Hills transitioning to loess. Based on our results, the approach may be used to increase the value of existing water table maps, and may be useful as a diagnostic tool to evaluate the quality of groundwater table maps, identify areas in need of detailed aquifer characterization and expansion of groundwater monitoring networks, and/or as a first approximation before investing in more complex approaches to groundwater recharge estimation.

  8. Prolongation of the deployment and monitoring of a multiple oscillating water column wave energy converter

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, F.; Chudley, J.; Dai, Y.M.

    2003-07-01

    This report summarises the findings of a project to prolong the sea trials of a multiple oscillating water column wave energy converter (MOWC) device for another 12 months to obtain further data. The objectives of the project include the evaluation of the ability of the MOWC to generate reliable energy to produce electricity, the estimation of the conversion efficiency, and the identification of improvements to increase the conversion efficiency, Details are given of the analysis of the sea trials data, and the performance of the broadband oscillating water column prototype.

  9. Parametric and scaling studies of condensation oscillation in subcooled water of the in-containment refueling water storage tank

    International Nuclear Information System (INIS)

    Lee, Jun Hyung; No, Hee Cheon

    1999-01-01

    Condensation oscillation by jetting the steam into subcooled water through spargers is studied. To provide a suitable guideline for oscillation phenomena in the IRWST of the next generation reactor, scaling methodology is introduced. Through scaling methodology and subsequent tests, it shows that the volume of steam cavity determines the dynamic characteristics of condensation oscillation. The second-order linear differential equation for frequency analysis is derived and its results are compared with those from the test data. Two types of condensation phenomena exist according to steam flow rates. At subsonic jet, condensation interface becomes irregular in shape and upper system volumes affect the dynamic characteristics of condensation oscillation. At sonic jet, a regular steam cavity forms at the exit of discharge holes. Parametric effects and subsequent dynamic responses of the pool tank are investigated through experiments in applicable test ranges. When the temperature of pool water becomes lower, the amplitude becomes larger. Critical parameters are derived from the scaling methodology and are system volume, cavity volume, discharge hole area, and density ration. It is found that system friction factors affect frequency components of condensation oscillation. Oscillations of a steam cavity occur mainly on the face of the axial direction and pressure amplitudes become larger than that of the lateral direction

  10. Water loss in table grapes: model development and validation under dynamic storage conditions

    Directory of Open Access Journals (Sweden)

    Ericsem PEREIRA

    2017-09-01

    Full Text Available Abstract Water loss is a critical problem affecting the quality of table grapes. Temperature and relative humidity (RH are essential in this process. Although mathematical modelling can be applied to measure constant temperature and RH impacts, it is proved that variations in storage conditions are normally encountered in the cold chain. This study proposed a methodology to develop a weight loss model for table grapes and validate its predictions in non-constant conditions of a domestic refrigerator. Grapes were maintained under controlled conditions and the weight loss was measured to calibrate the model. The model described the water loss process adequately and the validation tests confirmed its predictive ability. Delayed cooling tests showed that estimated transpiration rates in subsequent continuous temperature treatment was not significantly influenced by prior exposure conditions, suggesting that this model may be useful to estimate the weight loss consequences of interruptions in the cold chain.

  11. Analisa Kinerja Pneumatic Wave Energy Converter (WEC Dengan Menggunakan Oscillating Water Column(OWC

    Directory of Open Access Journals (Sweden)

    Rico Ary Sona

    2014-03-01

    Full Text Available Sistem konversi energi gelombang laut merupakan sistem yang menangkap energi gelombang laut untuk dikonversi menjadi energi lain seperti energi listrik. Salah satu jenis wave energy converter (WEC yang banyak digunakan diantaranya yaitu Oscillating Water Columnatau OWC. Prinsip kerja sistem WEC ini ialah mengubah pergerakan naik turunnya gelombang pada silinder kolom udara untuk menghasilkan udara bertekanan yang selanjutnya digunakan untuk menggerakkan turbin dan generator listrik. Penelitian ini ditujukan untuk dapat mengetahui kinerja dari Oscillating Water Column (OWC dalam menangkap energi gelombang laut. Untuk dapat melakukan penelitian ini diperlukan beberapa perlatan yaitu pembuatan konfigurasi peralatan pembuat dan penangkapan gelombang yang terdiri dari pelampung dan silinder Oscillating Water Column (OWC. Percobaan ini dilakukan dengan cara memvariasikan panjang dan tinggi gelombang pada flow water channel dengan mengatur bukaan pada pneumatic speed control. Dari hasil percobaan diperoleh bahwa kinerja paling efektif diperoleh pada panjang gelombang 0.9 m dan tinggi gelombang 0.23m. Pada karakteristik gelombang tersebut diperoleh tekanan, kecepatan dan volume pada silinder Oscillating Water Column (OWC sebesar  1.11 bar, 39.39 m/s dan 0.0057 m3. Dari hasil percobaan juga diperoleh waktu pengisian Pressure Vessel selama 100 menit dengan tekanan 3 Psi.

  12. Numerical prediction of the natural frequency of an Oscillating Water Column operating under resonant conditions

    Directory of Open Access Journals (Sweden)

    Marco Torresi

    2016-12-01

    Full Text Available Among the different technologies developed in order to harness wave energy, the Oscillating Water Column devices are the most accredited for an actual diffusion. Recently, Boccotti has patented the REWEC1 (REsonant sea Wave Energy Converter solution 1, a submerged breakwater that performs an active coast protection, embedding an Oscillating Water Column device, which is capable of operating under resonant conditions with that sea state, which gives the highest yearly energy contribution. The REWEC1 dynamic behavior can be approximated by means of a mass-spring-damper system. According to this approximation, a criterion for evaluating the oscillating natural frequency of the REWEC1 has been derived. This criterion has been validated against both experimental results and computational fluid dynamics simulations, performed on a REWEC1 laboratory-scale model. The numerical simulations have shown a good agreement between measurements and predictions.

  13. Simulating streamflow and water table depth with a coupled hydrological model

    Directory of Open Access Journals (Sweden)

    Alphonce Chenjerayi Guzha

    2010-09-01

    Full Text Available A coupled model integrating MODFLOW and TOPNET with the models interacting through the exchange of recharge and baseflow and river-aquifer interactions was developed and applied to the Big Darby Watershed in Ohio, USA. Calibration and validation results show that there is generally good agreement between measured streamflow and simulated results from the coupled model. At two gauging stations, average goodness of fit (R2, percent bias (PB, and Nash Sutcliffe efficiency (ENS values of 0.83, 11.15%, and 0.83, respectively, were obtained for simulation of streamflow during calibration, and values of 0.84, 8.75%, and 0.85, respectively, were obtained for validation. The simulated water table depths yielded average R2 values of 0.77 and 0.76 for calibration and validation, respectively. The good match between measured and simulated streamflows and water table depths demonstrates that the model is capable of adequately simulating streamflows and water table depths in the watershed and also capturing the influence of spatial and temporal variation in recharge.

  14. Water table depth fluctuations during ENSO phenomenon on different tropical peat swamp forest land covers in Katingan, Indonesia

    Science.gov (United States)

    Rossita, A.; Witono, A.; Darusman, T.; Lestari, D. P.; Risdiyanto, I.

    2018-03-01

    As it is the main role to maintain hydrological function, peatland has been a limelight since drainage construction for agriculture evolved. Drainage construction will decrease water table depth (WTD) and result in CO2 emission release to the atmosphere. Regardless of human intervention, WTD fluctuations can be affected by seasonal climate and climate variability, foremost El Niño Southern Oscillation (ENSO). This study aims to determine the correlation between rainfall in Katingan and ENSO index, analyze the pattern of WTD fluctuation of open area and forest area in 2015 (during very strong El Niño) and 2016 (during weak La Niña), calculate the WTD trendline slope during the dry season, and rainfall and WTD correlation. The result showed that open area has a sharper slope of decreasing or increasing WTD when entering the dry, compared to the forest area. Also, it is found that very strong El Niño in 2015 generated a pattern of more extreme decreasing WTD during the dry season than weak La Niña in 2016.

  15. The Inter Facility Testing of a Standard Oscillating Water Column (OWC) Type Wave Energy Converter (WEC)

    DEFF Research Database (Denmark)

    Andersen, Morten Thøtt; Thomsen, Jonas Bjerg

    This report describes the behavior and preliminary performance of a simplified standard oscillating water column (OWC) wave energy converter (WEC). The same tests will be conducted at different scales at 6 different test facilities and the results obtained will be used for comparison. This project...

  16. Investigation of low-frequency-oscillating water flow in metal foam with 10 pores per inch

    Science.gov (United States)

    Bağcı, Ö.; Arbak, A.; De Paepe, M.; Dukhan, N.

    2018-01-01

    In this study, oscillating water flow in metal foam with open cells is investigated experimentally. The metal foam sample has a porosity of 88% and 10 pores. The water was oscillated in the test section with three frequencies between 0.116 Hz and 0.348 Hz, which are considered low for water oscillation, and three flow displacements ranging between 74.35 mm and 111.53 mm. The combinations of frequencies of displacements were studied for their impacts of dimensional and non-dimensional pressure loss quantities. To this purpose, friction factor was correlated as a function of kinetic Reynolds number. The same metal foam sample was studied by exposing it to steady-state water flow to investigate its permeability and drag coefficient in low-velocity flow regimes. The friction factor distribution for oscillating flow was found to be over that found for steady state. The outcomes of the study are important for studying heat transfer under the same flow conditions.

  17. Scaling and parametric studies of condensation oscillation in an in-containment refueling water storage tank

    International Nuclear Information System (INIS)

    Lee, Jun Hyung; No, Hee Cheon

    2001-01-01

    The purpose of this paper is to study the condensation oscillation phenomena by steam-jetting into subcooled water through a sparger, implementing a scaling methodology and the similarity correlation between the test facility and model prototype. In additon, the results of this study can provide suitable guidelines for sparger design utilized in the IRWST for the Advanced Passive Reactor 1400 (APR 1400). To corroborate the scaling methodology, various experimental tests were conducted. The scaling-related parameters experimentally considered were water temperatures, mass flux, discharge system volumes, tank sizes, source pressure, steam-jetting directions, and numbers of sparger discharge holes. To preserve the scaling similarity, the thickness of the minimum water volume created by the boundary layer that encloses the steam cavity was found to be equal to the maximum length of the steam cavity formed. Four key scaling parameters were identified and empirically correlated with the maximum amplitude of pressure oscillation. They are as follows: Volume of the steam cavity, flow restriction coefficient, discharge hole area, and density ratio of steam to water. Variations of the oscillation amplitude were small when steam-jetting directions were altered. The concept of a reduction factor was introduced for estimating the oscillation amplitude of the multi-hole sparger with test data from a single-hole sparger

  18. Hanford site water table changes 1950-1980: data observations and evaluation

    International Nuclear Information System (INIS)

    Zimmerman, D.A.; Reisenauer, A.E.; Black, G.D.; Young, M.A.

    1986-04-01

    The basalt formations underlying the Hanford site are being considered for characterization and evaluation as a deep geologic repository for defense and commercial radioactive wastes. To understand the hydrology of the Hanford area, we need to know if the ground-water system is in steady state and what impact a change in surface stress from artificial recharge may have on the underlying basalt aquifers. Researchers at Pacific Northwest Laboratory are supporting efforts to understand these issues by illustrating how changes in wastewater disposal activities at the Hanford site have altered the configuration of the water table surface with time. The objective of this work was to determine the magnitude and direction of changes in the elevation of the water table across the Hanford site from 1950 to 1980. Plots of the magnitudes of water-level changes occurring over 5-year intervals from 1950 through 1980 are presented. The water-level changes that occurred during each 5-year interval are related to water discharges from nuclear fuel reprocessing facilities or other discharge sources. The plots of water-level changes show large water-level increases in the vicinity of the Separations Area (200 East and 200 West) from 1950 to 1960; the rate of increase of water-level changes grows more slowly from 1960 to 1970, while the areal extent of the mounding continues to expand. Only small changes occur from 1970 to 1980; during this time period, the unconfined system appears to be in approximate equilibrium with the sources. Based on previous experience, it is believed that an increase in ground-water mounding will begin to appear near the 200 East Area B Pond as a result of the increased discharges from the restart of PUREX in 1983

  19. "Periodic-table-style" paper device for monitoring heavy metals in water.

    Science.gov (United States)

    Li, Miaosi; Cao, Rong; Nilghaz, Azadeh; Guan, Liyun; Zhang, Xiwang; Shen, Wei

    2015-03-03

    If a paper-based analytical device (μ-PAD) could be made by printing indicators for detection of heavy metals in chemical symbols of the metals in a style of the periodic table of elements, it could be possible for such μ-PAD to report the presence and the safety level of heavy metal ions in water simultaneously and by text message. This device would be able to provide easy solutions to field-based monitoring of heavy metals in industrial wastewater discharges and in irrigating and drinking water. Text-reporting could promptly inform even nonprofessional users of the water quality. This work presents a proof of concept study of this idea. Cu(II), Ni(II), and Cr(VI) were chosen to demonstrate the feasibility, specificity, and reliability of paper-based text-reporting devices for monitoring heavy metals in water.

  20. Scaling and Parametric Studies of Condensation Oscillation in an In-Containment Refueling Water Storage Tank

    International Nuclear Information System (INIS)

    Lee, Jun Hyung; No, Hee Cheon

    2003-01-01

    The purpose of this paper is to study the condensation oscillation phenomena by steam-jetting into subcooled water through a multihole sparger, implementing a scaling methodology and the similarity correlation between the test facility and model prototype. To corroborate the scaling methodology, various experimental tests were conducted. The thickness of the boundary layer that encloses the steam cavity was found to be equal to the maximum length of the steam cavity formed. Three key scaling parameters were identified and correlated with the maximum amplitude of pressure oscillation: flow restriction coefficient, area ratio of discharge hole to steam cavity, and density ratio of water to steam. Variations of the oscillation amplitude were small when steam-jetting directions were altered. The concept of a reduction factor was introduced for estimating the oscillation amplitude of the multihole sparger with test data from a single-hole sparger. The results of this study can provide suitable guidelines for sparger design utilized in the in-containment refueling water storage tank for the Advanced Power Reactor 1400

  1. Investigation of oscillating airfoil shock phenomena

    OpenAIRE

    Giordano , Daniel; Fleeter , Sanford

    1992-01-01

    Fundamental experiments were performed in an unsteady flow water table facility to investigate and quantify the unsteady aerodynamics of a biconvex airfoil executing torsion mode oscillations at realistic reduced frequencies. A computer-based image enhancement system was used to measure the oscillating supersonic and transonic shock flow phenomena. By utilizing the hydraulic analogy to compare experimental results with a linear theoretical prediction, magnitude and phase relationships for the...

  2. Investigation of the resonant power oscillation in the Halden Boiling Water Reactor by autoregressive modeling

    International Nuclear Information System (INIS)

    Oguma, Ritsuo

    1980-01-01

    In the HBWR (Halden Boiling Water Reactor), there exists a resonant power oscillation with period about 0.04 Hz at power levels higher than about 9.5 MWt. While the resonant oscillation in not so large as to affect the normal reactor operation, it is significant, from the viewpoint of reactor diagnosis, to grasp its characteristics and find the cause. Noise analysis based on the autoregressive (AR) modeling technique has been made to reveal the driving source for this oscillation which led to the suggestion that it is attributed to the dynamic interference of heat exchange process between two parallel-connected steam transformers against the reactor. The present study demonstrates that the method used here is highly effective for tracing back to a noise source inducing the variation of quantities in a system, and also applicable to problems of reactor noise analysis and diagnosis. (author)

  3. Effects of Permanently Raised Water Tables on Forest Overstory Vegetation in the Vicinity of the Tennessee-Tombigbee Waterway.

    Science.gov (United States)

    1982-08-01

    Mississippi Valley* Common Name Scientific Name Very Tolerant** Water hickory Carya aquatica Pecan C. illinoensis Buttonbush Cephalanthus occidentalis...Table I (Concluded) Common Name Scientific Name Intolerant* Ironwood Carpinus caroliniana Bitternut hickory Carya cordiformis Shellbark

  4. Water table and overbank flow frequency changes due to suburbanization-induced channel incision, Virginia Coastal Plain, USA

    Science.gov (United States)

    Hancock, G.; Mattell, N.; Christianson, E.; Wacksman, J.

    2004-12-01

    Channel incision is a widely observed response to increased flow in urbanized watersheds, but the effects of channel lowering on riparian water tables is not well documented. In a rapidly incising suburban stream in the Virginia Coastal Plain, we hypothesize that incision has lowered floodplain water tables and decreased the overbank flow frequency, and suggest these changes impact vegetation distribution in a diverse, protected riparian habitat. The monitored stream is a tributary to the James River draining 1.3 km2, of which 15% is impervious cover. Incision has occurred largely through upstream migration of a one m high knickpoint at a rate of 1-2 m/yr, primarily during high flow events. We installed 33 wells in six floodplain transects to assess water table elevations beneath the floodplain adjacent to the incising stream. To document the impacts of incision, two transects are located 30 and 50 m upstream of the knickpoint in unincised floodplain, and the remainder are 5, 30, 70, and 100 m downstream of the knickpoint in incised floodplain. In one transect above and two below, pressure transducers attached to dataloggers provide a high-resolution record of water table response to storm events. Significant differences have been observed in the water table above and below the knickpoint. Above the knickpoint, the water table is relatively flat and is 0.2-0.4 m below the floodplain surface. Water table response to precipitation events is nearly immediate, with the water table rising to the floodplain surface in significant rainfall events. In the transect immediately downstream of the knickpoint, the water table possesses a steep gradient, rising from ~1 m below the floodplain at the stream to 0.3 m below the surface within 20 m. In the most downstream transects, the water table is relatively flat, but is one m below the floodplain surface, equivalent to the depth of incision generated by knickpoint passage. Upstream of the knickpoint, overbank flooding occurs

  5. Water transport inside carbon nanotubes mediated by phonon-induced oscillating friction.

    Science.gov (United States)

    Ma, Ming; Grey, François; Shen, Luming; Urbakh, Michael; Wu, Shuai; Liu, Jefferson Zhe; Liu, Yilun; Zheng, Quanshui

    2015-08-01

    The emergence of the field of nanofluidics in the last decade has led to the development of important applications including water desalination, ultrafiltration and osmotic energy conversion. Most applications make use of carbon nanotubes, boron nitride nanotubes, graphene and graphene oxide. In particular, understanding water transport in carbon nanotubes is key for designing ultrafiltration devices and energy-efficient water filters. However, although theoretical studies based on molecular dynamics simulations have revealed many mechanistic features of water transport at the molecular level, further advances in this direction are limited by the fact that the lowest flow velocities accessible by simulations are orders of magnitude higher than those measured experimentally. Here, we extend molecular dynamics studies of water transport through carbon nanotubes to flow velocities comparable with experimental ones using massive crowd-sourced computing power. We observe previously undetected oscillations in the friction force between water and carbon nanotubes and show that these oscillations result from the coupling between confined water molecules and the longitudinal phonon modes of the nanotube. This coupling can enhance the diffusion of confined water by more than 300%. Our results may serve as a theoretical framework for the design of new devices for more efficient water filtration and osmotic energy conversion devices.

  6. High-Resolution Assimilation of GRACE Terrestrial Water Storage Observations to Represent Local-Scale Water Table Depths

    Science.gov (United States)

    Stampoulis, D.; Reager, J. T., II; David, C. H.; Famiglietti, J. S.; Andreadis, K.

    2017-12-01

    Despite the numerous advances in hydrologic modeling and improvements in Land Surface Models, an accurate representation of the water table depth (WTD) still does not exist. Data assimilation of observations of the joint NASA and DLR mission, Gravity Recovery and Climate Experiment (GRACE) leads to statistically significant improvements in the accuracy of hydrologic models, ultimately resulting in more reliable estimates of water storage. However, the usually shallow groundwater compartment of the models presents a problem with GRACE assimilation techniques, as these satellite observations account for much deeper aquifers. To improve the accuracy of groundwater estimates and allow the representation of the WTD at fine spatial scales we implemented a novel approach that enables a large-scale data integration system to assimilate GRACE data. This was achieved by augmenting the Variable Infiltration Capacity (VIC) hydrologic model, which is the core component of the Regional Hydrologic Extremes Assessment System (RHEAS), a high-resolution modeling framework developed at the Jet Propulsion Laboratory (JPL) for hydrologic modeling and data assimilation. The model has insufficient subsurface characterization and therefore, to reproduce groundwater variability not only in shallow depths but also in deep aquifers, as well as to allow GRACE assimilation, a fourth soil layer of varying depth ( 1000 meters) was added in VIC as the bottom layer. To initialize a water table in the model we used gridded global WTD data at 1 km resolution which were spatially aggregated to match the model's resolution. Simulations were then performed to test the augmented model's ability to capture seasonal and inter-annual trends of groundwater. The 4-layer version of VIC was run with and without assimilating GRACE Total Water Storage anomalies (TWSA) over the Central Valley in California. This is the first-ever assimilation of GRACE TWSA for the determination of realistic water table depths, at

  7. Environmental impact assessment of quarries under water table: state of the art

    International Nuclear Information System (INIS)

    Menatti, M.; Vismara, R.

    2009-01-01

    After an overview of environmental problems concerning pits under water table, data and results showed in a few examples of literature and in some Environmental Impact Study are summarized. A close examination about sector normative instruments, in the field of E.I.A. (Environmental Impact Assessment) and S.E.A. (Strategic Environmental Assessment) is showed, through some key elements obtained from a few guidelines expressed by control and authorization governmental authority.In addition, the paper deals with a specific problem about wash water management and, in particular, silt material management; the possible impacts derived from the directly wash water introduction in the pit lake and from the use of settling lagoon are analyzed. [it

  8. Measuring the Change in Water Table with Gravity Methods - a Controlled Experiment

    DEFF Research Database (Denmark)

    Lund, S; Christiansen, Lars; Andersen, O. B.

    2009-01-01

    Gravity changes linearly with the change in soil water content. With the GRACE satellite mission the interest for ground-based gravity methods in hydrology has gained new attention. Time-lapse gravity data have the potential to constrain hydrological model parameters in a calibration scheme....... The greatest potential is seen for specific yield. The gravity signal from hydrology is small (10^-8 m/s^2 level) and the application of ground-based methods is mainly limited by the sensitivity of available instruments. In order to demonstrate the ability of the Scintrex CG-5 gravity meter to detect a change...... in water content, a controlled experiment was set up in 30 m by 20 m basin. The water table was lowered 0.69 m within 1½ hours and the corresponding gravity signal measured using two different approaches: a time series measurements at one location and a gravity network measurement including four points...

  9. A study on the influence of tides on the water table conditions of the shallow coastal aquifers

    Science.gov (United States)

    Singaraja, C.; Chidambaram, S.; Jacob, Noble

    2018-03-01

    Tidal variation and water level in aquifer is an important function in the coastal environment, this study attempts to find the relationship between water table fluctuation and tides in the shallow coastal aquifers. The study was conducted by selecting three coastal sites and by monitoring the water level for every 2-h interval in 24 h of observation. The study was done during two periods of full moon and new moon along the Cuddalore coastal region of southern part of Tamil Nadu, India. The study shows the relationship between tidal variation, water table fluctuations, dissolved oxygen, and electrical conductivity. An attempt has also been made in this study to approximate the rate of flow of water. Anyhow, the differences are site specific and the angle of inclination of the water table shows a significant relation to the mean sea level, with respect to the distance of the point of observation from the sea and elevation above mean sea level.

  10. Secondary mineral evidence of large-scale water table fluctuations at Yucca Mountain, Nye County, Nevada

    International Nuclear Information System (INIS)

    Whelan, J.F.; Moscati, R.J.; Marshall, B.D

    1997-12-01

    At Yucca Mountain, currently under consideration as a potential permanent underground repository for high-level radioactive wastes, the present-day water table is 500 to 700 m deep. This thick unsaturated zone (UZ) is part of the natural barrier system and is regarded as a positive attribute of the potential site. The USGS has studied the stable isotopes and petrography of secondary calcite and silica minerals that coat open spaces in the UZ and form irregular veins and masses in the saturated zone (SZ). This paper reviews the findings from the several studies undertaken at Yucca Mountain on its mineralogy

  11. Effectiveness of table top water pitcher filters to remove arsenic from drinking water.

    Science.gov (United States)

    Barnaby, Roxanna; Liefeld, Amanda; Jackson, Brian P; Hampton, Thomas H; Stanton, Bruce A

    2017-10-01

    Arsenic contamination of drinking water is a serious threat to the health of hundreds of millions of people worldwide. In the United States ~3 million individuals drink well water that contains arsenic levels above the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10μg/L. Several technologies are available to remove arsenic from well water including anion exchange, adsorptive media and reverse osmosis. In addition, bottled water is an alternative to drinking well water contaminated with arsenic. However, there are several drawbacks associated with these approaches including relatively high cost and, in the case of bottled water, the generation of plastic waste. In this study, we tested the ability of five tabletop water pitcher filters to remove arsenic from drinking water. We report that only one tabletop water pitcher filter tested, ZeroWater®, reduced the arsenic concentration, both As 3+ and As 5+ , from 1000μg/L to water and its use reduces plastic waste associated with bottled water. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Water flow patterns induced by bridge oscillation of magnetic fluid between two permanent magnets subjected to alternating magnetic field

    International Nuclear Information System (INIS)

    Sudo, Seiichi; Yamamoto, Kazuki; Ishimoto, Yukitaka; Nix, Stephanie

    2017-01-01

    This paper describes the characteristics of water flow induced by the bridge oscillation of magnetic fluid between two permanent magnets subject to an external alternating magnetic field. The magnetic fluid bridge is formed in the space between a pair of identical coaxial cylindrical permanent magnets submerged in water. The direction of alternating magnetic field is parallel /antiparallel to the magnetic field produced by two permanent magnets. The magnetic fluid bridge responds to the external alternating magnetic field with harmonic oscillation. The oscillation of magnetic fluid bridge generates water flow around the bridge. Water flow is visualized using a thin milk film at the container bottom. Water flows are observed with a high-speed video camera analysis system. The experimental results show that the flow pattern induced by the bridge oscillation depends on the Keulegan–Carpenter number.

  13. Water flow patterns induced by bridge oscillation of magnetic fluid between two permanent magnets subjected to alternating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Sudo, Seiichi, E-mail: sudo@akita-pu.ac.jp [Faculty of Systems Science and Technology, Akita Prefectural University, Ebinokuchi 84-4, Yurihonjo 015-0055 (Japan); Yamamoto, Kazuki [Graduate School of Engineering, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Ishimoto, Yukitaka; Nix, Stephanie [Faculty of Systems Science and Technology, Akita Prefectural University, Ebinokuchi 84-4, Yurihonjo 015-0055 (Japan)

    2017-06-01

    This paper describes the characteristics of water flow induced by the bridge oscillation of magnetic fluid between two permanent magnets subject to an external alternating magnetic field. The magnetic fluid bridge is formed in the space between a pair of identical coaxial cylindrical permanent magnets submerged in water. The direction of alternating magnetic field is parallel /antiparallel to the magnetic field produced by two permanent magnets. The magnetic fluid bridge responds to the external alternating magnetic field with harmonic oscillation. The oscillation of magnetic fluid bridge generates water flow around the bridge. Water flow is visualized using a thin milk film at the container bottom. Water flows are observed with a high-speed video camera analysis system. The experimental results show that the flow pattern induced by the bridge oscillation depends on the Keulegan–Carpenter number.

  14. Understanding and quantifying focused, indirect groundwater recharge from ephemeral streams using water table fluctuations

    Science.gov (United States)

    Cuthbert, M. O.; Acworth, R. I.; Andersen, M. S.; Larsen, J. R.; McCallum, A. M.; Rau, G. C.; Tellam, J. H.

    2016-02-01

    Understanding and managing groundwater resources in drylands is a challenging task, but one that is globally important. The dominant process for dryland groundwater recharge is thought to be as focused, indirect recharge from ephemeral stream losses. However, there is a global paucity of data for understanding and quantifying this process and transferable techniques for quantifying groundwater recharge in such contexts are lacking. Here we develop a generalized conceptual model for understanding water table and groundwater head fluctuations due to recharge from episodic events within ephemeral streams. By accounting for the recession characteristics of a groundwater hydrograph, we present a simple but powerful new water table fluctuation approach to quantify focused, indirect recharge over both long term and event time scales. The technique is demonstrated using a new, and globally unparalleled, set of groundwater observations from an ephemeral stream catchment located in NSW, Australia. We find that, following episodic streamflow events down a predominantly dry channel system, groundwater head fluctuations are controlled by pressure redistribution operating at three time scales from vertical flow (days to weeks), transverse flow perpendicular to the stream (weeks to months), and longitudinal flow parallel to the stream (years to decades). In relative terms, indirect recharge decreases almost linearly away from the mountain front, both in discrete monitored events as well as in the long-term average. In absolute terms, the estimated indirect recharge varies from 80 to 30 mm/a with the main uncertainty in these values stemming from uncertainty in the catchment-scale hydraulic properties.

  15. The effect of changing water table on methane fluxes at two Finnish mire sites

    International Nuclear Information System (INIS)

    Martikainen, P.J.; Nykaenen, H.; Crill, P.; Silvola, J.

    1992-01-01

    Methane fluxes were measured using static chamber technique on a minerotrophic fen and an ombrotrophic peat bog site located in the Lakkasuo mire complex in central Finland. Both sites consisted of a virgin area and an area drained in 1961 by ditching. The measurements in 1991 were made biweekly from spring thaw to winter freezing. During this period, the mean CH4 emission from the virgin minerotrophic site and virgin ombrotrophic site was 98 mg/m -2 d -1 and 40 mg/m -2 d -1 , respectively. The mean emission of CH 4 from the drained ombrotrophic site was 18 mg/m -2 d -1 . The drained minerotrophic site consumed methane during most of the measuring period, the average uptake was 0.13 mg/m2d. Draining had lowered the average water table by 4 cm at the ombrotrophic site and by 20 cm at minerotrophic site. The possible reasons for the different development of the water table and methane fluxes at ombrotrophic and minerotrophic sites after drainer are discussed

  16. Peatland pines as a proxy for water table fluctuations: disentangling tree growth, hydrology and possible human influence.

    Science.gov (United States)

    Smiljanić, Marko; Seo, Jeong-Wook; Läänelaid, Alar; van der Maaten-Theunissen, Marieke; Stajić, Branko; Wilmking, Martin

    2014-12-01

    Dendrochronological investigations of Scots pine (Pinus sylvestris L.) growing on Männikjärve peatland in central Estonia showed that annual tree growth of peatland pines can be used as a proxy for past variations of water table levels. Reconstruction of past water table levels can help us to better understand the dynamics of various ecological processes in peatlands, e.g. the formation of vegetation patterns or carbon and nitrogen cycling. Männikjärve bog has one of the longest water table records in the boreal zone, continuously monitored since 1956. Common uncertainties encountered while working with peatland trees (e.g. narrow, missing and wedging rings) were in our case exacerbated with difficulties related to the instability of the relationship between tree growth and peatland environment. We hypothesized that the instable relationship was mainly due to a significant change of the limiting factor, i.e. the rise of the water table level due to human activity. To test our hypothesis we had to use several novel methods of tree-ring chronology analysis as well as to test explicitly whether undetected missing rings biased our results. Since the hypothesis that the instable relationship between tree growth and environment was caused by a change in limiting factor could not be rejected, we proceeded to find possible significant changes of past water table levels using structural analysis of the tree-ring chronologies. Our main conclusions were that peatland pines can be proxies to water table levels and that there were several shifting periods of high and low water table levels in the past 200 years. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Effects of soil water table regime on tree community species richness and structure of alluvial forest fragments in Southeast Brazil.

    Science.gov (United States)

    Silva, A C; Higuchi, P; van den Berg, E

    2010-08-01

    In order to determine the influence of soil water table fluctuation on tree species richness and structure of alluvial forest fragments, 24 plots were allocated in a point bar forest and 30 plots in five forest fragments located in a floodplain, in the municipality of São Sebastião da Bela Vista, Southeast Brazil, totalizing 54, 10 X 20 m, plots. The information recorded in each plot were the soil water table level, diameter at breast height (dbh), total height and botanical identity off all trees with dbh > 5 cm. The water table fluctuation was assessed through 1 m deep observation wells in each plot. Correlations analysis indicated that sites with shallower water table in the flooding plains had a low number of tree species and high tree density. Although the water table in the point bar remained below the wells during the study period, low tree species richness was observed. There are other events taking place within the point bar forest that assume a high ecological importance, such as the intensive water velocity during flooding and sedimentation processes.

  18. Effects of soil water table regime on tree community species richness and structure of alluvial forest fragments in Southeast Brazil

    Directory of Open Access Journals (Sweden)

    AC. Silva

    Full Text Available In order to determine the influence of soil water table fluctuation on tree species richness and structure of alluvial forest fragments, 24 plots were allocated in a point bar forest and 30 plots in five forest fragments located in a floodplain, in the municipality of São Sebastião da Bela Vista, Southeast Brazil, totalizing 54, 10 X 20 m, plots. The information recorded in each plot were the soil water table level, diameter at breast height (dbh, total height and botanical identity off all trees with dbh > 5 cm. The water table fluctuation was assessed through 1 m deep observation wells in each plot. Correlations analysis indicated that sites with shallower water table in the flooding plains had a low number of tree species and high tree density. Although the water table in the point bar remained below the wells during the study period, low tree species richness was observed. There are other events taking place within the point bar forest that assume a high ecological importance, such as the intensive water velocity during flooding and sedimentation processes.

  19. Climate change and water table fluctuation: Implications for raised bog surface variability

    Science.gov (United States)

    Taminskas, Julius; Linkevičienė, Rita; Šimanauskienė, Rasa; Jukna, Laurynas; Kibirkštis, Gintautas; Tamkevičiūtė, Marija

    2018-03-01

    Cyclic peatland surface variability is influenced by hydrological conditions that highly depend on climate and/or anthropogenic activities. A low water level leads to a decrease of peatland surface and an increase of C emissions into the atmosphere, whereas a high water level leads to an increase of peatland surface and carbon sequestration in peatlands. The main aim of this article is to evaluate the influence of hydrometeorological conditions toward the peatland surface and its feedback toward the water regime. A regional survey of the raised bog water table fluctuation and surface variability was made in one of the largest peatlands in Lithuania. Two appropriate indicators for different peatland surface variability periods (increase and decrease) were detected. The first one is an 200 mm y- 1 average net rainfall over a three-year range. The second one is an average annual water depth of 25-30 cm. The application of these indicators enabled the reconstruction of Čepkeliai peatland surface variability during a 100 year period. Processes of peatland surface variability differ in time and in separate parts of peatland. Therefore, internal subbasins in peatland are formed. Subbasins involve autogenic processes that can later affect their internal hydrology, nutrient status, and vegetation succession. Internal hydrological conditions, surface fluctuation, and vegetation succession in peatland subbasins should be taken into account during evaluation of their state, nature management projects, and other peatland research works.

  20. Development of Historical Water Table Maps of the 200 West Area of the Hanford Site (1950-1970)

    International Nuclear Information System (INIS)

    Kinney, Teena M.; McDonald, John P.

    2006-01-01

    A series of detailed historical water-table maps for the 200-West Area of the Hanford Site was made to aid interpretation of contaminant distribution in the upper aquifer. The contaminants are the result of disposal of large volumes of waste to the ground during Hanford Site operations, which began in 1944 and continued into the mid-1990s. Examination of the contaminant plumes that currently exist on site shows that the groundwater beneath the 200-West Area has deviated from its pre-Hanford west-to-east flow direction during the past 50 years. By using historical water-level measurements from wells around the 200-West Area, it was possible to create water-table contour maps that show probable historic flow directions. These maps are more detailed than previously published water-table maps that encompass the entire Hanford Site.

  1. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips - Part 1: nonuniform infiltration and soil water redistribution

    OpenAIRE

    Munoz Carpena, R.; Lauvernet, C.; Carluer, N.

    2018-01-01

    Vegetation buffers like vegetative filter strips (VFSs) are often used to protect water bodies from surface runoff pollution from disturbed areas. Their typical placement in floodplains often results in the presence of a seasonal shallow water table (WT) that can decrease soil infiltration and increase surface pollutant transport during a rainfall-runoff event. Simple and robust components of hydrological models are needed to analyze the impacts of WT in the landscape. To si...

  2. CORRELATION BETWEEN RAINFALL PATTERNS AND THE WATER TABLE IN THE GENERAL SEPARATIONS AREA OF THE SAVANNAH RIVER SITE

    International Nuclear Information System (INIS)

    Smith, C.

    2009-01-01

    The objective of the study was to evaluate rainfall and water table elevation data in search of a correlation that could be used to understand and predict water elevation changes. This information will be useful in placing screen zones for future monitoring wells and operations of groundwater treatment units. Fifteen wells in the General Separations Area (GSA) at Savannah River Site were evaluated from 1986 through 2001. The study revealed that the water table does respond to rainfall with minimal delay. (Water level information was available monthly, which restricted the ability to evaluate a shorter delay period.) Water elevations were found to be related to the cumulative sum (Q-Delta Sum) of the difference between the average rainfall for a specific month and the actual rainfall for that month, calculated from an arbitrary starting point. Water table elevations could also be correlated between wells, but using the right well for correlation was very important. The strongest correlation utilized a quadratic equation that takes into account the rainfall in a specific area and the rainfall from an adjacent area that contributes through a horizontal flow. Specific values vary from well to well as a result of geometry and underground variations. R2's for the best models ranged up to 0.96. The data in the report references only GSA wells but other wells (including confined water tables) on the site have been observed to return similar water level fluctuation patterns

  3. The impact of water table drawdown and drying on subterranean aquatic fauna in in-vitro experiments.

    Directory of Open Access Journals (Sweden)

    Christine Stumpp

    Full Text Available The abstraction of groundwater is a global phenomenon that directly threatens groundwater ecosystems. Despite the global significance of this issue, the impact of groundwater abstraction and the lowering of groundwater tables on biota is poorly known. The aim of this study is to determine the impacts of groundwater drawdown in unconfined aquifers on the distribution of fauna close to the water table, and the tolerance of groundwater fauna to sediment drying once water levels have declined. A series of column experiments were conducted to investigate the depth distribution of different stygofauna (Syncarida and Copepoda under saturated conditions and after fast and slow water table declines. Further, the survival of stygofauna under conditions of reduced sediment water content was tested. The distribution and response of stygofauna to water drawdown was taxon specific, but with the common response of some fauna being stranded by water level decline. So too, the survival of stygofauna under different levels of sediment saturation was variable. Syncarida were better able to tolerate drying conditions than the Copepoda, but mortality of all groups increased with decreasing sediment water content. The results of this work provide new understanding of the response of fauna to water table drawdown. Such improved understanding is necessary for sustainable use of groundwater, and allows for targeted strategies to better manage groundwater abstraction and maintain groundwater biodiversity.

  4. Numerical study on the characteristics of air bubble oscillation in water

    International Nuclear Information System (INIS)

    Kim, Hwan Yeol; Bae, Yoon Yeong

    2003-01-01

    In both a boiling water reactor and an advanced type of pressurized water reactor under construction in Korea named APR1400, when a pressure relieving system is in operation, water, air and steam discharge successively into a sub-cooled water pool through spargers. Among the phenomena occurring during the discharging processes, the air bubble clouds with a low-frequency and high-amplitude oscillation may result in significant damage to the submerged structures if the resonance between the bubble clouds and structures occur. The phenomena involved are so complicated that most predictions of frequency and pressure loads have resorted to experimental work and computational approach has been precluded. This study deals with a numerical prediction of the pressure field generated by the oscillation of air bubble. The analysis was performed by using a commercial thermal hydraulic analysis code, FLUENT, version 4.5. The multiphase flows of water, air and steam were simulated by the VOF (Volume Of Fluid) model contained in the code. Unlike the author's previous study, the LRR (Load Reduction Ring) of the sparger is artificially blocked for the investigation of LRR effects on the pressure field. It also includes the effect of air mass and inlet pressure in the piping on the pressure field. (author)

  5. Study of energy transfer in table-top X-pinch driven by a water line

    International Nuclear Information System (INIS)

    Beg, F N; Zhang, T; Fedin, D; Beagen, B; Chua, E; Lee, J Y; Rawat, R S; Lee, P

    2007-01-01

    The current passing through X-pinches and the energy transferring from the pulse forming line to the load are modelled using a simple LCR circuit. A comparison of the electrical properties of two table-top X-pinch devices is made. It was found that up to 25% of the stored energy is transferred from the water transmission line to the load in the University of California,San Diego (UCSD) table-top X-pinch before x-ray emission starts. The highest energy transmitted (75%) is found after the current peak. In comparison, only 3% of the energy is transferred to the load in the National Institute of Education (NIE) X-pinch device just after the maximum current peak. The highest energy (25%) transmitted to the plasma occurs long after the current peak. The plasma in both devices is visually and qualitatively similar. However, the UCSD device emits intense x-rays with no x-rays observed in the NIE device. This observation is consistent with the electrical circuit analysis

  6. Precipitation patterns and moisture fluxes in a sandy, tropical environment with a shallow water table

    Science.gov (United States)

    Minihane, M. R.; Freyberg, D. L.

    2011-08-01

    Identifying the dominant mechanisms controlling recharge in shallow sandy soils in tropical climates has received relatively little attention. Given the expansion of coastal fill using marine sands and the growth of coastal populations throughout the tropics, there is a need to better understand the nature of water balances in these settings. We use time series of field observations at a coastal landfill in Singapore coupled with numerical modeling using the Richards' equation to examine the impact of precipitation patterns on soil moisture dynamics, including percolation past the root zone and recharge, in such an environment. A threshold in total precipitation event depth, much more so than peak precipitation intensity, is the strongest event control on recharge. However, shallow antecedent moisture, and therefore the timing between events along with the seasonal depth to water table, also play significant roles in determining recharge amounts. For example, at our field site, precipitation events of less than 3 mm per event yield little to no direct recharge, but for larger events, moisture content changes below the root zone are linearly correlated to the product of the average antecedent moisture content and the total event precipitation. Therefore, water resources planners need to consider identifying threshold precipitation volumes, along with the multiple time scales that capture variability in event antecedent conditions and storm frequency in assessing the role of recharge in coastal water balances in tropical settings.

  7. Depth dependent microbial carbon use efficiency in the capillary fringe as affected by water table fluctuations in a column incubation experiment

    Science.gov (United States)

    Pronk, G. J.; Mellage, A.; Milojevic, T.; Smeaton, C. M.; Rezanezhad, F.; Van Cappellen, P.

    2017-12-01

    Microbial growth and turnover of soil organic carbon (SOC) depend on the availability of electron donors and acceptors. The steep geochemical gradients in the capillary fringe between the saturated and unsaturated zones provide hotspots of soil microbial activity. Water table fluctuations and the associated drying and wetting cycles within these zones have been observed to lead to enhanced turnover of SOC and adaptation of the local microbial communities. To improve our understanding of SOC degradation under changing moisture conditions, we carried out an automated soil column experiment with integrated of hydro-bio-geophysical monitoring under both constant and oscillating water table conditions. An artificial soil mixture composed of quartz sand, montmorillonite, goethite and humus was used to provide a well-defined system. This material was inoculated with a microbial community extracted from a forested riparian zone. The soils were packed into 6 columns (60 cm length and 7.5 cm inner diameter) to a height of 45 cm; and three replicate columns were incubated under constant water table while another three were saturated and drained monthly. The initial soil development, carbon cycling and microbial community development were then characterized during 10 months of incubation. This system provides an ideal artificial gradient from the saturated to the unsaturated zone to study soil development from initially homogeneous materials and the same microbial community composition under controlled conditions. Depth profiles of SOC and microbial biomass after 329 days of incubation showed a depletion of carbon in the transition drying and wetting zone that was not associated with higher accumulation of microbial biomass, indicating a lower carbon use efficiency of the microbial community established within the water table fluctuation zone. This was supported by a higher ATP to microbial biomass carbon ratio within the same zone. The findings from this study highlight the

  8. Moderate drop in water table increases peatland vulnerability to post-fire regime shift.

    Science.gov (United States)

    Kettridge, N; Turetsky, M R; Sherwood, J H; Thompson, D K; Miller, C A; Benscoter, B W; Flannigan, M D; Wotton, B M; Waddington, J M

    2015-01-27

    Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon.

  9. Iron-mediated soil carbon response to water-table decline in an alpine wetland

    Science.gov (United States)

    Wang, Yiyun; Wang, Hao; He, Jin-Sheng; Feng, Xiaojuan

    2017-06-01

    The tremendous reservoir of soil organic carbon (SOC) in wetlands is being threatened by water-table decline (WTD) globally. However, the SOC response to WTD remains highly uncertain. Here we examine the under-investigated role of iron (Fe) in mediating soil enzyme activity and lignin stabilization in a mesocosm WTD experiment in an alpine wetland. In contrast to the classic `enzyme latch' theory, phenol oxidative activity is mainly controlled by ferrous iron [Fe(II)] and declines with WTD, leading to an accumulation of dissolvable aromatics and a reduced activity of hydrolytic enzyme. Furthermore, using dithionite to remove Fe oxides, we observe a significant increase of Fe-protected lignin phenols in the air-exposed soils. Fe oxidation hence acts as an `iron gate' against the `enzyme latch' in regulating wetland SOC dynamics under oxygen exposure. This newly recognized mechanism may be key to predicting wetland soil carbon storage with intensified WTD in a changing climate.

  10. Small leak detection by measuring surface oscillation during sodium-water reaction in steam generator

    International Nuclear Information System (INIS)

    Nei, Hiromichi; Hori, Masao

    1977-01-01

    Small leak sodium-water reaction tests were conducted to develop various kinds of leak detectors for the sodium-heated steam generator in FBR. The super-heated steam was injected into sodium in a reaction vessel having a sodium free surface, simulating the steam generator. The level gauge in the reaction vessel generated the most reliable signal among detectors, as long as the leak rates were relatively high. The level gauge signal was estimated to be the sodium surface oscillation caused by hydrogen bubbles produced in sodium-water reaction. Experimental correlation was derived, predicting the amplitude as a function of leak rate, hydrogen dissolution ratio, bubble rise velocity and other parameters concerned, assuming that the surface oscillation is in proportion to the gas hold-up. The noise amplitude under normal operation without water leak was increased with sodium flow rate and found to be well correlated with Froud number. These two correlations predict that a water leak in a ''MONJU'' class (300 MWe) steam generator could possibly be detected by level gauges at a leak rate above 2 g/sec. (auth.)

  11. Electrical Resistivity Imaging of Tidal Fluctuations in the Water Table at Inwood Hill Park, Manhattan

    Science.gov (United States)

    Kenyon, P. M.; Kassem, D.; Olin, A.; Nunez, J.; Smalling, A.

    2005-05-01

    Inwood Hill Park is located on the northern tip of Manhattan and has been extensively modified over the years by human activities. In its current form, it has a backbone of exposed or lightly covered bedrock along the Hudson River, adjacent to a flat area with two tidal inlets along the northern shore of Manhattan. The tidal motions in the inlets are expected to drive corresponding fluctuations in the water table along the borders of the inlets. In the Fall of 2002, a group of students from the Department of Earth and Atmospheric Sciences at the City College of New York studied these fluctuations. Electrical resistivity cross sections were obtained with a Syscal Kid Switch 24 resistivity meter during the course of a tidal cycle at three locations surrounding the westernmost inlet in the park. No change was seen over a tidal cycle at Site 1, possibly due to the effect of concrete erosion barriers which were located between the land and the water surrounding this site. Measurements at Site 2 revealed a small, regular change in the water table elevation of approximately 5 cm over the course of a tidal cycle. This site is inferred to rest on alluvial sediments deposited by a small creek. The cross sections taken at different times during a tidal cycle at Site 3 were the most interesting. They show a very heterogeneous subsurface, with water spurting between blocks of high resistivity materials during the rising portion of the cycle. A small sinkhole was observed on the surface of the ground directly above an obvious plume of water in the cross section. Park personnel confirmed that this sinkhole, like others scattered around this site, is natural and not due to recent construction activity. They also indicated that debris from the construction of the New York City subways may have been dumped in the area in the past. Our conclusion is that the tidal fluctuations at Site 3 are being channeled by solid blocks in the construction debris, and that the sinkholes currently

  12. Bathymetric maps and water-quality profiles of Table Rock and North Saluda Reservoirs, Greenville County, South Carolina

    Science.gov (United States)

    Clark, Jimmy M.; Journey, Celeste A.; Nagle, Doug D.; Lanier, Timothy H.

    2014-01-01

    Lakes and reservoirs are the water-supply source for many communities. As such, water-resource managers that oversee these water supplies require monitoring of the quantity and quality of the resource. Monitoring information can be used to assess the basic conditions within the reservoir and to establish a reliable estimate of storage capacity. In April and May 2013, a global navigation satellite system receiver and fathometer were used to collect bathymetric data, and an autonomous underwater vehicle was used to collect water-quality and bathymetric data at Table Rock Reservoir and North Saluda Reservoir in Greenville County, South Carolina. These bathymetric data were used to create a bathymetric contour map and stage-area and stage-volume relation tables for each reservoir. Additionally, statistical summaries of the water-quality data were used to provide a general description of water-quality conditions in the reservoirs.

  13. Culture of microalgae biomass for valorization of table olive processing water

    International Nuclear Information System (INIS)

    Contreras, C.G.; Serrano, A.; Ruiz-Filippi, G.; Borja, R.; Fermoso, F.G.

    2016-01-01

    Table olive processing water (TOPW) contains many complex substances, such as phenols, which could be valorized as a substrate for microalgae biomass culture. The aim of this study was to assess the capability of Nannochloropsis gaditana to grow in TOPW at different concentrations (10- 80%) in order to valorize this processing water. Within this range, the highest increment of biomass was determined at percentage of 40% of TOPW, reaching an increment of 0.36 ± 0.05 mg volatile suspended solids (VSS)/L. Components of algal biomass were similar for the experiments at 10-40% of TOPW, where proteins were the major compounds (56-74%). Total phenols were retained in the microalgae biomass (0.020 ± 0.002 g of total phenols/g VSS). Experiments for 80% of TOPW resulted in a low production of microalgae biomass. High organic matter, nitrogen, phosphorus and phenol removal were achieved in all TOPW concentrations. Although high-value products, such as proteins, were obtained and high removal efficiencies of nutrients were determined, microalgae biomass culture should be enhanced to become a suitable integral processing water treatment. [es

  14. A Modified Water-Table Fluctuation Method to Characterize Regional Groundwater Discharge

    Directory of Open Access Journals (Sweden)

    Lihong Yang

    2018-04-01

    Full Text Available A modified Water-Table Fluctuation (WTF method is developed to quantitatively characterize the regional groundwater discharge patterns in stressed aquifers caused by intensive agricultural pumping. Two new parameters are defined to express the secondary information in the observed data. One is infiltration efficiency and the other is discharge modulus (recurring head loss due to aquifer discharge. An optimization procedure is involved to estimate these parameters, based on continuous groundwater head measurements and precipitation records. Using the defined parameters and precipitation time series, water level changes are calculated for individual wells with fidelity. The estimated parameters are then used to further address the characterization of infiltration and to better quantify the discharge at the regional scale. The advantage of this method is that it considers recharge and discharge simultaneously, whereas the general WTF methods mostly focus on recharge. In the case study, the infiltration efficiency reveals that the infiltration is regionally controlled by the intrinsic characteristics of the aquifer, and locally distorted by engineered hydraulic structures that alter surface water-groundwater interactions. The seasonality of groundwater discharge is characterized by the monthly discharge modulus. These results from individual wells are clustered into groups that are consistent with the local land use pattern and cropping structures.

  15. Effects of high-rate wastewater spray disposal on the water-table aquifer, Hilton Head Island, South Carolina

    Science.gov (United States)

    Speiran, G.K.

    1985-01-01

    A study by the U.S. Geological Survey from April 1982 through December 1983 evaluated the effects of high-rate disposal of treated wastewater on the water table aquifer, Hilton Head Island, South Carolina. Flooding of topographically low areas resulted from the application of 10.8 inches of wastewater in 10 days in January 1983. The water table remained 2-1/2 to 5-1/2 feet below land surface when wastewater was applied at rates of 5 inches per week in August and December 1983. (USGS)

  16. Ground-water sampling of the NNWSI (Nevada Nuclear Waste Storage Investigation) water table test wells surrounding Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Matuska, N.A.

    1988-12-01

    The US Geological Survey (USGS), as part of the Nevada Nuclear Waste Storage Investigation (NNWSI) study of the water table in the vicinity of Yucca Mountain, completed 16 test holes on the Nevada Test Site and Bureau of Land Management-administered lands surrounding Yucca Mountain. These 16 wells are monitored by the USGS for water-level data; however, they had not been sampled for ground-water chemistry or isotropic composition. As part of the review of the proposed Yucca Mountain high-level nuclear waste repository, the Desert Research Institute (DRI) sampled six of these wells. The goal of this sampling program was to measure field-dependent parameters of the water such as electrical conductivity, pH, temperature and dissolved oxygen, and to collect samples for major and minor element chemistry and isotopic analysis. This information will be used as part of a program to geochemically model the flow direction between the volcanic tuff aquifers and the underlying regional carbonate aquifer

  17. Measurements of natural frequency and damping constant of single steam bubble oscillating in water

    International Nuclear Information System (INIS)

    Morioka, Mikio

    1983-01-01

    The natural frequency fsub(n) and damping constant delta of a bubble in liquid have been determined by observing the resonance of the bubble to forced oscillation. The bubble was retained under a rigid plate horizontal disk, and the oscillation was applied by underwater speaker. The applied frequency f was kept constant while letting the bubble increase its volume and vary its radius R. Bubble resonance was detected by observing wrinkles appearing on the bubble due to surface waves. Resonance curves relating the amplitude of bubble radius variation to the intensity of applied oscillation is derived theoretically. Good agreement was seen between the data obtained from experiment and the theoretically derived resonance curves at test to the validity of the method proposed of determining fsub(n) and delta from bubble resonance. The values of delta and of the resonant bubble radius R 0 of large steam bubbles (8.5mm< R<11.5mm) in water were determined at f=270, 290 and 358 Hz. The results support the assumption that for large bubbles the value of fsub(n) is little influenced by the exchange of mass between liquid and gaseous phases through evaporation and condensation accompanying bubble pressure oscillation. On the other hand, delta is found to be one order of magnitude higher than calculated for steam bubbles without taking into evaporation and condensation the interphase exchange of mass. The effect brought on delta by the interphase mass exchange can be taken into account by adding a new constant deltasub(ph) to the terms constituting the total damping constant. (author)

  18. Decadal oscillations of the aquatic chemistry of river waters in Latvia

    Directory of Open Access Journals (Sweden)

    D. Porshnov

    2016-10-01

    Full Text Available Water quality changes of surface waters can be used to assess human impact intensity, but of importance is to consider also impacts of climate change/variability and naturally occurring changes of environmental quality. In Latvia, during the recent decades a major reduction of anthropogenic pressure has happened due to restructuring of economy and industrial production, resulting in major decrease of loading of many groups of pollutants. However, trends and driving factors for other groups of substances have not been much studied. Long term (1980–2012 results of hydrochemical monitoring, performed in rivers of Latvia, are analysed during this study in connection with long-term sets of hydrological and heliophysical data, using standard statistical approaches. Our results indicate that variation of some hydrochemical values, for example COD and total Fe, show clearly visible decadal oscillated character, while variation of some other values, for example phosphate P and total P, show some individual characteristics of decadal oscillations. These results indicate the presence of a large scale, geochemical and geophysical significant process: multiannual pulse of catchment, driven by variation of solar irradiance through complex interactions between global atmospheric circulation, groundwater and surface waterbodies. The process described in our study is significant from a geochemical point of view and must be taken into account in prediction of water quality and quantity. Impacts of natural processes should be considered in the planning of environmental policy.

  19. Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations

    Directory of Open Access Journals (Sweden)

    Roshan GholamReza

    2012-12-01

    Full Text Available Abstract The rapid rise of Caspian Sea water level (about 2.25 meters since 1978 has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006 and future (2025-2100 time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3. The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21. The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82 between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

  20. Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations.

    Science.gov (United States)

    Roshan, Gholamreza; Moghbel, Masumeh; Grab, Stefan

    2012-12-12

    The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm) by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

  1. Large-scale regionalization of water table depth in peatlands optimized for greenhouse gas emission upscaling

    Science.gov (United States)

    Bechtold, M.; Tiemeyer, B.; Laggner, A.; Leppelt, T.; Frahm, E.; Belting, S.

    2014-09-01

    Fluxes of the three main greenhouse gases (GHG) CO2, CH4 and N2O from peat and other soils with high organic carbon contents are strongly controlled by water table depth. Information about the spatial distribution of water level is thus a crucial input parameter when upscaling GHG emissions to large scales. Here, we investigate the potential of statistical modeling for the regionalization of water levels in organic soils when data covers only a small fraction of the peatlands of the final map. Our study area is Germany. Phreatic water level data from 53 peatlands in Germany were compiled in a new data set comprising 1094 dip wells and 7155 years of data. For each dip well, numerous possible predictor variables were determined using nationally available data sources, which included information about land cover, ditch network, protected areas, topography, peatland characteristics and climatic boundary conditions. We applied boosted regression trees to identify dependencies between predictor variables and dip-well-specific long-term annual mean water level (WL) as well as a transformed form (WLt). The latter was obtained by assuming a hypothetical GHG transfer function and is linearly related to GHG emissions. Our results demonstrate that model calibration on WLt is superior. It increases the explained variance of the water level in the sensitive range for GHG emissions and avoids model bias in subsequent GHG upscaling. The final model explained 45% of WLt variance and was built on nine predictor variables that are based on information about land cover, peatland characteristics, drainage network, topography and climatic boundary conditions. Their individual effects on WLt and the observed parameter interactions provide insight into natural and anthropogenic boundary conditions that control water levels in organic soils. Our study also demonstrates that a large fraction of the observed WLt variance cannot be explained by nationally available predictor variables and

  2. Upper Bound Solution for the Face Stability of Shield Tunnel below the Water Table

    Directory of Open Access Journals (Sweden)

    Xilin Lu

    2014-01-01

    Full Text Available By FE simulation with Mohr-Coulomb perfect elastoplasticity model, the relationship between the support pressure and displacement of the shield tunnel face was obtained. According to the plastic strain distribution at collapse state, an appropriate failure mechanism was proposed for upper bound limit analysis, and the formula to calculate the limit support pressure was deduced. The limit support pressure was rearranged to be the summation of soil cohesion c, surcharge load q, and soil gravity γ multiplied by their corresponding coefficients Nc, Nq, and Nγ, and parametric studies were carried out on these coefficients. In order to consider the influence of seepage on the face stability, the pore water pressure distribution and the seepage force on the tunnel face were obtained by FE simulation. After adding the power of seepage force into the equation of the upper bound limit analysis, the total limit support pressure for stabilizing the tunnel face under seepage condition was obtained. The total limit support pressure was shown to increase almost linearly with the water table.

  3. Control of xenon oscillations in Advanced Heavy Water Reactor via two-stage decomposition

    International Nuclear Information System (INIS)

    Munje, R.K.; Parkhe, J.G.; Patre, B.M.

    2015-01-01

    Highlights: • Singularly perturbed model of Advanced Heavy Water Reactor is explored. • Composite controller is designed using slow subsystem alone, which achieves asymptotic stability. • Nonlinear simulations are carried out under different transient conditions. • Performance of the controller is found to be satisfactory. - Abstract: Xenon induced spatial oscillations developed in large nuclear reactors, like Advanced Heavy Water Reactor (AHWR) need to be controlled for safe operation. Otherwise, a serious situation may arise in which different regions of the core may undergo variations in neutron flux in opposite phase. If these oscillations are left uncontrolled, the power density and rate of change of power at some locations in the reactor core may exceed their respective thermal limits, resulting in fuel failure. In this paper, a state feedback based control strategy is investigated for spatial control of AHWR. The nonlinear model of AHWR including xenon and iodine dynamics is characterized by 90 states, 5 inputs and 18 outputs. The linear model of AHWR, obtained by linearizing the nonlinear equations is found to be highly ill-conditioned. This higher order model of AHWR is first decomposed into two comparatively lower order subsystems, namely, 73rd order ‘slow’ subsystem and 17th order ‘fast’ subsystem using two-stage decomposition. Composite control law is then derived from individual subsystem feedback controls and applied to the vectorized nonlinear model of AHWR. Through the dynamic simulations it is observed that the controller is able to suppress xenon induced spatial oscillations developed in AHWR and the overall performance is found to be satisfactory

  4. Pneumatic Performance of a Non-Axisymmetric Floating Oscillating Water Column Wave Energy Conversion Device in Random Waves

    OpenAIRE

    Bull, Diana

    2014-01-01

    A stochastic approach is used to gain a sophisticated understanding of a non-axisymmetric floating oscillating water column's response to random waves. A linear, frequency-domain performance model that links the oscillating structure to air-pressure fluctuations with a Wells Turbine in 3-dimensions is used to study the device performance at a northern California deployment location. Both short-term, sea-state, and long-term, annual, predictions are made regarding the devices performance. U...

  5. Non-methane biogenic volatile organic compound emissions from boreal peatland microcosms under warming and water table drawdown

    DEFF Research Database (Denmark)

    Faubert, P; Tiiva, P; Nakam, TA

    2011-01-01

    assessed the combined effect of warming and water table drawdown on the BVOC emissions from boreal peatland microcosms. We also assessed the treatment effects on the BVOC emissions from the peat soil after the 7-week long experiment. Emissions of isoprene, monoterpenes, sesquiterpenes, other reactive VOCs...

  6. The leaching of radioactivity from highly radioactive glass blocks buried below the water table: fifteen years of results

    International Nuclear Information System (INIS)

    Merritt, W.F.

    1976-03-01

    The results from two test burials of high-level fission products incorporated into nepheline syenite glass indicate that the nuclear wastes from fuel processing for a 30,000 MWe nuclear power industry could be incorporated into such glass and stored beneath the water table in the waste management area of Chalk River Nuclear Laboratories (CRNL) without harm to the environment. (author)

  7. Water table response to harvesting and simulated emerald ash borer mortality in black ash wetlands in Minnesota, USA

    Science.gov (United States)

    Robert A. Slesak; Christian F. Lenhart; Kenneth N. Brooks; Anthony W. D' Amato; Brian J. Palik

    2014-01-01

    Black ash wetlands are seriously threatened because of the invasive emerald ash borer (EAB). Wetland hydrology is likely to be modified following ash mortality, but the magnitude of hydrological impact following loss via EAB and alternative mitigation harvests is not clear. Our objective was to assess the water table response to simulated EAB and harvesting to...

  8. Spectral detection of near-surface moisture content and water-table position in northern peatland ecosystems

    Science.gov (United States)

    Karl M. Meingast; Michael J. Falkowski; Evan S. Kane; Lynette R. Potvin; Brian W. Benscoter; Alistair M.S. Smith; Laura L. Bourgeau-Chavez; Mary Ellen. Miller

    2014-01-01

    Wildland fire occurrence has been increasing in peatland ecosystems during recent decades. As such, there is a need for broadly applicable tools to detect and monitor controls on combustion such as surface peat moisture and water-table position. A field portable spectroradiometer was used to measure surface reflectance of two Sphagnum moss-dominated...

  9. Ecosystem respiration in a heterogeneous temperate peatland and its sensitivity to peat temperature and water table depth

    Czech Academy of Sciences Publication Activity Database

    Juszczak, R.; Humphreys, E.; Acosta, Manuel; Michalak-Galczewska, M.; Kayzer, D.; Olejnik, Janusz

    2013-01-01

    Roč. 366, 1-2 (2013), s. 505-520 ISSN 0032-079X Institutional support: RVO:67179843 Keywords : Ecosystem respiration * Geogenous peatland * Chamber measurements * CO2 fluxes * Water table depth Subject RIV: EH - Ecology, Behaviour Impact factor: 3.235, year: 2013

  10. Interactive plant functional group and water table effects on decomposition and extracellular enzyme activity in Sphagnum peatlands

    Science.gov (United States)

    Magdalena M. Wiedermann; Evan S. Kane; Lynette R. Potvin; Erik A. Lilleskov

    2017-01-01

    Peatland decomposition may be altered by hydrology and plant functional groups (PFGs), but exactly how the latter influences decomposition is unclear, as are potential interactions of these factors.We used a factorial mesocosm experiment with intact 1 m3 peat monoliths to explore how PFGs (sedges vs Ericaceae) and water table level individually...

  11. LITHOLOGIC CONDITIONS OF THE WATER TABLE LOGGING IN THE AREA OF HAĆKI VILLAGE IN THE BIELSKA PLAIN

    Directory of Open Access Journals (Sweden)

    Krzysztof Micun

    2016-05-01

    Full Text Available The aim of the study was to examine lithological conditions of the water table in the area of Haćki village located in the Bielska Plain. The study involved the measurements of water level in dug wells, hand drill probing to a depth of 5 m, acquiring the samples of water-bearing deposits and analysing their granulation. The results of analyses allowed to calculate the permeability coefficient. The geological structure of the area is dominated by dusty deposits of various origins. Such deposits’ formation directly affects the conditions of filtration and depth of the water table. Groundwater logging near Haćki village in the Bielska Plain appears at a depth of several tens of centimeters to 2 meters in the depressions field and up a little over 5 meters in the case of higher ground surfaces. The presence of perched water was revealed on the hills, periodic leachates at the foot of the hills and scarps and one periodic spring. Water-bearing deposits are medium sands, fine sands and loamy fine sands or fine sands with silt. Consequently, the permeability coefficient is low or even very low. Its values range from 0,001 m·d-1 to 3,8 m·d-1 (d – 24 hours. The widespread presence of dusty deposits in the area affects the limited efficiency of the water table.

  12. Observations of electric discharge streamer propagation and capillary oscillations on the surface of air bubbles in water

    Energy Technology Data Exchange (ETDEWEB)

    Sommers, B S; Foster, J E [Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI, 48109 (United States); Babaeva, N Yu; Kushner, Mark J [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109 (United States)

    2011-03-02

    The propagation of electric discharge streamers inside bubbles in liquids is of interest for the remediation of toxins in water and plasma-based surgical instruments. The manner of streamer propagation has an important influence on the production of reactive species that are critical to these applications. Streamer propagation along the surface of electrode-attached bubbles of air in water, previously predicted by numerical simulations, has been experimentally imaged using a fast frame-rate camera. The successive pulsing of the streamer discharge inside the bubbles produced oscillations along the air-water interface. Subsequent streamers were observed to closely follow surface distortions induced by such oscillations. The oscillations likely arise from the non-uniform perturbation of the bubble driven by the electric field of the streamer and were found to be consistent with Kelvin's equation for capillary oscillations. For a narrow range of applied voltage pulse frequencies, the oscillation amplitude increased over several pulse periods indicating, potentially, resonant behaviour. We also observed coupling between bubbles wherein oscillations in a second bubble without an internal discharge were induced by the presence of a streamer in a fixed bubble. (fast track communication)

  13. Basic prerequisites and the practice of using deep water tables for burying liquid radioactive wastes

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Pimenov, M.K.; Balukova, V.D.; Leontichuk, A.S.; Kokorin, I.N.; Yudin, F.P.; Rakov, N.A.

    In the USSR, creating reservoirs for liquid radioactive wastes is one of the promising methods of safely disposing of them in deep water tables, in zones with a standing regime or a slow rate of subterranean water exchange. The results of investigations and the practice of burying (the wastes) indicate the reliability and effectiveness of such a method of final waste disposal when the basic requirements of environmental protection are observed. Geological formations and collector strata that guarantee the localization of the liquid radioactive wastes placed in them for many tens and even hundreds of thousands of years can be studied and chosen in different regions. The basic requirements and criteria to which the geological structures and collector strata must correspond for ensuring the safe burial of wastes have been formulated. Wastes are buried only after a comprehensive, scientifically based evaluation of the sanitary-radiation safety for this generation and future ones, taking into account the burial regime and the physico-chemical processes that accompany combining wastes with rocks and stratal waters, as well as the time of holding wastes to maximum permissible concentrations. Positive and negative factors that characterize the method are analyzed. Possible emergency situations with subterranean burial are evaluated. The composition and methods of the geological survey, hydrodynamic, geophysical, physico-chemical and sanitary-radiation investigations; methods of calculating and predicting the movement of wastes underground;methods of preparing wastes for burial and chemical methods of restoring the suitability of wells; design characteristics and conditions of preparing wells for use; methods of estimating heating and processes of radiolysis for a medium containing highly radioactive wastes; methods of operational and remote control of the burial process and the condition of the ambient medium, etc. are briefly examined

  14. The impact of long-term changes in water table height on carbon cycling in sub-boreal peatlands

    Science.gov (United States)

    Pypker, T. G.; Moore, P. A.; Waddington, J. M.; Hribljan, J. A.; Ballantyne, D.; Chimner, R. A.

    2011-12-01

    Peatlands are a critical component in the global carbon (C) cycle because they have been slowly sequestering atmospheric greenhouse gases as peat since the last glaciation. Today, soil C stocks in peatlands are estimated to represent 224 to 455 Pg, equal to 12-30% of the global soil C pool. At present, peatlands are estimated to sequester 76 Tg C yr-1. The flux of C to and from peatlands is likely to respond to climate change, thereby influencing atmospheric C concentrations. Peatland C budgets are tightly linked to their hydrology, hence, it is critical we understand how changes in hydrology will affect the C budgets of peatlands. The main objective of the project was to determine how long-term changes in water table height affect CO2 and CH4 fluxes from three adjacent peatlands. This study took place in the Seney National Wildlife Refuge (SNWR) in the Upper Peninsula of Michigan. SNWR is home to the largest wetland drainage project in Michigan. In 1912, ditches and dikes were created in an effort to convert approximately 20,000 ha of peatland to agriculture. The ditches and dikes were unsuccessful in creating agricultural land, but they are still in place. The manipulation of water table heights provides an opportunity to research how long-term peat drying or wetting alters C cycling in peatlands. From May to November in 2009, 2010 and 2011, we monitored CO2 fluxes using eddy covariance and chamber techniques in three adjacent peatlands with lowered, relatively unaltered ("control") and raised water table heights. In 2011, we installed CH4 analyzers to continuously monitor CH4 fluxes at the sites with high and relatively unaltered water table heights. The results are compared across sites to determine how changes in water table height might affect C fluxes sub-boreal peatlands.

  15. Holes in the Bathtub: Water Table Dependent Services and Threshold Behavior in an Economic Model of Groundwater Extraction

    Science.gov (United States)

    Kirk-lawlor, N. E.; Edwards, E. C.

    2012-12-01

    In many groundwater systems, the height of the water table must be above certain thresholds for some types of surface flow to exist. Examples of flows that depend on water table elevation include groundwater baseflow to river systems, groundwater flow to wetland systems, and flow to springs. Meeting many of the goals of sustainable water resource management requires maintaining these flows at certain rates. Water resource management decisions invariably involve weighing tradeoffs between different possible usage regimes and the economic consequences of potential management choices are an important factor in these tradeoffs. Policies based on sustainability may have a social cost from forgoing present income. This loss of income may be worth bearing, but should be well understood and carefully considered. Traditionally, the economic theory of groundwater exploitation has relied on the assumption of a single-cell or "bathtub" aquifer model, which offers a simple means to examine complex interactions between water user and hydrologic system behavior. However, such a model assumes a closed system and does not allow for the simulation of groundwater outflows that depend on water table elevation (e.g. baseflow, springs, wetlands), even though those outflows have value. We modify the traditional single-cell aquifer model by allowing for outflows when the water table is above certain threshold elevations. These thresholds behave similarly to holes in a bathtub, where the outflow is a positive function of the height of the water table above the threshold and the outflow is lost when the water table drops below the threshold. We find important economic consequences to this representation of the groundwater system. The economic value of services provided by threshold-dependent outflows (including non-market value), such as ecosystem services, can be incorporated. The value of services provided by these flows may warrant maintaining the water table at higher levels than would

  16. Numerical study of the air-flow in an oscillating water column wave energy converter

    Energy Technology Data Exchange (ETDEWEB)

    Paixao Conde, J.M. [Department of Mechanical and Industrial Engineering, Faculty of Sciences and Technology, New University of Lisbon, Monte de Caparica, 2829-516 Caparica (Portugal); IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, 1049-001 Lisboa (Portugal); Gato, L.M.C. [IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, 1049-001 Lisboa (Portugal)

    2008-12-15

    The paper presents a numerical study of the air-flow in a typical pneumatic chamber geometry of an oscillating water column (OWC)-type wave energy converter (WEC), equipped with two vertical-axis air turbines, asymmetrically placed on the top of the chamber. Outwards and inwards, steady and periodic, air-flow calculations were performed to investigate the flow distribution at the turbines' inlet sections, as well as the properties of the air-jet impinging on the water free-surface. The original design of the OWC chamber is likely to be harmful for the operation of the turbines due to the possible air-jet-produced water-spray at the water free-surface subsequently ingested by the turbine. A geometry modification of the air chamber, using a horizontal baffle-plate to deflect the air from the turbines, is proposed and proved to be very effective in reducing the risk of water-spray production from the inwards flow. The flow distribution at the turbines' inlet sections for the outwards flow was found to be fairly uniform for the geometries considered, providing good inlet flow conditions for the turbines. Steady flow was found to be an acceptable model to study the air-flow inside the pneumatic chamber of an OWC-WEC. (author)

  17. Effects of water table position and plant functional group on plant community, aboveground production, and peat properties in a peatland mesocosm experiment (PEATcosm)

    Science.gov (United States)

    Lynette R. Potvin; Evan S. Kane; Rodney A. Chimner; Randall K. Kolka; Erik A. Lilleskov

    2015-01-01

    Aims Our objective was to assess the impacts of water table position and plant functional type on peat structure, plant community composition and aboveground plant production. Methods We initiated a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional groups (PFG: sedge, Ericaceae,...

  18. Simulation of the water-table altitude in the Biscayne Aquifer, southern Dade County, Florida, water years 1945-89

    Science.gov (United States)

    Merritt, M.L.

    1995-01-01

    A digital model of the flow system in the highly permeable surficial aquifer of southern Dade County, Florida, was constructed for the purposes of better understanding processes that influence the flow system and of supporting the construction of a subregional model of the transport of brackish water from a flowing artesian well. Problems that needed resolution in this endeavor included the development of methods to represent the influence of flowing surface water in seasonally inundated wetlands and the influence of a network of controlled canals developed in stages during the simulation time period (water years 1945-89). An additional problem was the general lack of natural aquifer boundaries near the boundaries of the study area. The model construction was based on a conceptual description of the Biscayne aquifer developed from the results of previous U.S. Geological Survey investigations. Modifications were made to an existing three- dimensional finite-difference simulator of ground- water flow to enable an upper layer of the grid to represent seasonally occurring overland sheetflow in a series of transient simulations of water levels from 1945 to 1989. A rewetting procedure was developed for the simulator that permitted resaturation of cells in this layer when the wet season recurred. An "equivalent hydraulic conductivity" coefficient was assigned to the overland flow layer that was analogous, subject to various approximations, to the use of the Manning equation. The surficial semiconfining peat and marl layers, levees, canals, and control structures were also represented as part of the model grid with the appropriate choices of hydraulic coefficient values. For most of the Biscayne aquifer grid cells, the value assigned to hydraulic conductivity for model calibration was 30,000 feet per day and the value assigned to porosity was 20 percent. Boundary conditions were specified near data sites having long-term records of surface-water stages or water-table

  19. Estimating evapotranspiration and groundwater flow from water-table fluctuations for a general wetland scenario

    Science.gov (United States)

    Weber, Lisa C.; Wiley, Michael J.; Wilcox, Douglas A.

    2016-01-01

    The use of diurnal water-table fluctuation methods to calculate evapotranspiration (ET) and groundwater flow is of increasing interest in ecohydrological studies. Most studies of this type, however, have been located in riparian wetlands of semi-arid regions where groundwater levels are consistently below topographic surface elevations and precipitation events are infrequent. Current methodologies preclude application to a wider variety of wetland systems. In this study, we extended a method for estimating sub-daily ET and groundwater flow rates from water-level fluctuations to fit highly dynamic, non-riparian wetland scenarios. Modifications included (1) varying the specific yield to account for periodic flooded conditions and (2) relating empirically derived ET to estimated potential ET for days when precipitation events masked the diurnal signal. To demonstrate the utility of this method, we estimated ET and groundwater fluxes over two growing seasons (2006–2007) in 15 wetlands within a ridge-and-swale wetland complex of the Laurentian Great Lakes under flooded and non-flooded conditions. Mean daily ET rates for the sites ranged from 4.0 mm d−1 to 6.6 mm d−1. Shallow groundwater discharge rates resulting from evaporative demand ranged from 2.5 mm d−1 to 4.3 mm d−1. This study helps to expand our understanding of the evapotranspirative demand of plants under various hydrologic and climate conditions. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  20. Methane transport and emissions from soil as affected by water table and vascular plants.

    Science.gov (United States)

    Bhullar, Gurbir S; Iravani, Majid; Edwards, Peter J; Olde Venterink, Harry

    2013-09-08

    The important greenhouse gas (GHG) methane is produced naturally in anaerobic wetland soils. By affecting the production, oxidation and transport of methane to the atmosphere, plants have a major influence upon the quantities emitted by wetlands. Different species and functional plant groups have been shown to affect these processes differently, but our knowledge about how these effects are influenced by abiotic factors such as water regime and temperature remains limited. Here we present a mesocosm experiment comparing eight plant species for their effects on internal transport and overall emissions of methane under contrasting hydrological conditions. To quantify how much methane was transported internally through plants (the chimney effect), we blocked diffusion from the soil surface with an agar seal. We found that graminoids caused higher methane emissions than forbs, although the emissions from mesocosms with different species were either lower than or comparable to those from control mesocosms with no plant (i.e. bare soil). Species with a relatively greater root volume and a larger biomass exhibited a larger chimney effect, though overall methane emissions were negatively related to plant biomass. Emissions were also reduced by lowering the water table. We conclude that plant species (and functional groups) vary in the degree to which they transport methane to the atmosphere. However, a plant with a high capacity to transport methane does not necessarily emit more methane, as it may also cause more rhizosphere oxidation of methane. A shift in plant species composition from graminoids to forbs and/or from low to high productive species may lead to reduction of methane emissions.

  1. [The marketing evaluation of the consumers' preference as regards the use of medicinal and medicinal table mineral waters].

    Science.gov (United States)

    Babaskin, D V; Babaskina, L I; Pavlova, A V

    2017-12-28

    The development of modern technologies in physiotherapy with the use of mineral waters, the expansion of the assortment of the medicinal and medicinal table waters as well as increasing the competitive advantages of domestic products require the more extensive marketing survey of the consumers' preferences in the market of mineral waters. The objective of the present study was the marketing evaluation of the consumers' preference in the segment of medicinal and medicinal table mineral waters in the city of Moscow. The survey involved 697 consumers of medicinal and medicinal table mineral waters. The sampling was carried out by the deterministic quota method. The field research was conducted by means of personal verbal interviews (32%) and the CATI to Web method (phone recruiting and on-line questioning) (68%) with the use of the structured questionnaire. Positioning was carried out making use of the two-dimensional schematic map and scoring assessment on an individual basis with calculation of integrated indicators. The marketing evaluation has demonstrated that the principal motive for purchasing mineral waters in more than 40% of respondents was the treatment and prevention of various diseases including disturbances in the urogenital system as well as digestive and respiratory disorders that appear to be the most frequent reasons for the consumption of mineral waters. The main factors that form the preferences of the consumers as regards the use of a concrete variety of mineral waters were elucidated. Of crucial importance for approximately 40% of the consumers (p<0.01) proved to be their health condition, the medical indications, and the available information about the therapeutic effectiveness of one or another type of mineral waters. Other factors were the quality of mineral water, its cost, the manufacturer and/or place of production, the attractiveness of the packaging, etc. The evaluation of the positioning of the mineral water consumers' preferences made

  2. Influence of subcooled boiling on out-of-phase oscillations in boiling water reactors

    International Nuclear Information System (INIS)

    Munoz-Cobo, J.L.; Chiva, S.; Escriva, A.

    2005-01-01

    In this paper, we develop a reduced order model with modal kinetics for the study of the dynamic behavior of boiling water reactors. This model includes the subcooled boiling in the lower part of the reactor channels. New additional equations have been obtained for the following dynamics magnitudes: the effective inception length for subcooled boiling, the average void fraction in the subcooled boiling region, the average void fraction in the bulk-boiling region, the mass fluxes at the boiling boundary and the channel exit, respectively, and so on. Each channel has three nodes, one of liquid, one with subcooled boiling, and one with bulk boiling. The reduced order model includes also a modal kinetics with the fundamental mode and the first subcritical one, and two channels representing both halves of the reactor core. Also, in this paper, we perform a detailed study of the way to calculate the feedback reactivity parameters. The model displays out-of-phase oscillations when enough feedback gain is provided. The feedback gain that is necessary to self-sustain these oscillations is approximately one-half the gain that is needed when the subcooled boiling node is not included

  3. Control of spatial xenon oscillations in pressurized water reactors via the Kalman filter

    International Nuclear Information System (INIS)

    Lin, C.; Lin, Y.J.

    1994-01-01

    A direct control method is developed to control the spatial xenon oscillations in pressurized water reactors. The xenon and iodine concentration difference between the top and bottom halves of the core is estimated by using the extended Kalman filter (EKF), which is a closed-loop estimation method. The measurement equation used in the observer is the axial offset measurement equation, which reflects the xenon unbalanced effect on the axial offset. Meanwhile, some of the coefficients of the observer are estimated on-line to reduce estimation error resulting from model error, i.e., simplified xenon and iodine dynamics. Therefore, the estimation can be guaranteed to be accurate, and the success of the estimation does not greatly depend on the accuracy of the observer model. The predicted one-step ahead xenon concentration, by using the EKF, was used to calculate the possible axial offset variation, and then the control rod motion was calculated to compensate for it. The simulation results show that the proposed method successfully controls the xenon oscillations

  4. Development of synchronized, autonomous, and self-regulated oscillations in transpiration rate of a whole tomato plant under water stress.

    Science.gov (United States)

    Wallach, Rony; Da-Costa, Noam; Raviv, Michael; Moshelion, Menachem

    2010-07-01

    Plants respond to many environmental changes by rapidly adjusting their hydraulic conductivity and transpiration rate, thereby optimizing water-use efficiency and preventing damage due to low water potential. A multiple-load-cell apparatus, time-series analysis of the measured data, and residual low-pass filtering methods were used to monitor continuously and analyse transpiration of potted tomato plants (Solanum lycopersicum cv. Ailsa Craig) grown in a temperature-controlled greenhouse during well-irrigated and drought periods. A time derivative of the filtered residual time series yielded oscillatory behaviour of the whole plant's transpiration (WPT) rate. A subsequent cross-correlation analysis between the WPT oscillatory pattern and wet-wick evaporation rates (vertical cotton fabric, 0.14 m(2) partly submerged in water in a container placed on an adjacent load cell) revealed that autonomous oscillations in WPT rate develop under a continuous increase in water stress, whereas these oscillations correspond with the fluctuations in evaporation rate when water is fully available. The relative amplitude of these autonomous oscillations increased with water stress as transpiration rate decreased. These results support the recent finding that an increase in xylem tension triggers hydraulic signals that spread instantaneously via the plant vascular system and control leaf conductance. The regulatory role of synchronized oscillations in WPT rate in eliminating critical xylem tension points and preventing embolism is discussed.

  5. Numerical Simulation of a Dual-Chamber Oscillating Water Column Wave Energy Converter

    Directory of Open Access Journals (Sweden)

    Dezhi Ning

    2017-09-01

    Full Text Available The performance of a dual-chamber Oscillating Water Column (OWC Wave Energy Converter (WEC is considered in the present study. The device has two sub-chambers with a shared orifice. A two-dimensional (2D fully nonlinear numerical wave flume based on the potential-flow theory and the time-domain higher-order boundary element method (HOBEM is applied for the simulation. The incident waves are generated by using the immerged sources and the air-fluid coupling influence is considered with a simplified pneumatic model. In the present study, the variation of the surface elevation and the water column volume in the two sub-chambers are investigated. The effects of the chamber geometry (i.e., the draft and breadth of two chambers on the surface elevation and the air pressure in the chamber are investigated, respectively. It is demonstrated that the surface elevations in the two sub-chambers are strongly dependent on the wave conditions. The larger the wavelength, the more synchronous motion of the two water columns in the two sub-chambers, thus, the lager the variation of the water column volume.

  6. Water Table Depth Reconstruction in Ombrotrophic Peatlands Using Biomarker Abundance Ratios and Compound-Specific Hydrogen Isotope Composition

    Science.gov (United States)

    Nichols, J. E.; Jackson, S. T.; Booth, R. K.; Pendall, E. G.; Huang, Y.

    2005-12-01

    Sediment cores from ombrotrophic peat bogs provide sensitive records of changes in precipitation/evaporation (P/E) balance. Various proxies have been developed to reconstruct surface moisture conditions in peat bogs, including testate amoebae, plant macrofossils, and peat humification. Studying species composition of testate amoeba assemblages is time consuming and requires specialized training. Humification index can be influenced by environmental factors other than moisture balance. The plant macrofossil proxy is less quantitative and cannot be performed on highly decomposed samples. We demonstrate that the ratio of C23 alkane to C29 alkane abundance may provide a simple alternative or complementary means of tracking peatland water-table depth. Data for this proxy can be collected quickly using a small sample (100 mg dry). Water-table depth decreases during drought, and abundance of Sphagnum, the dominant peat-forming genus, decreases as vascular plants increase. Sphagnum moss produces mainly medium chain-length alkanes (C21-C25) while vascular plants (grasses and shrubs) produce primarily longer chain-length alkanes (C27-C31). Therefore, C23:C29 n-alkane ratios quantitatively track the water table depth fluctuations in peat bogs. We compared C23:C29 n-alkane ratios in a core from Minden Bog (southeastern Michigan) with water table depth reconstructions based on testate-amoeba assemblages and humification. The 184-cm core spans the past ~3kyr of continuous peat deposition in the bog. Our results indicate that the alkane ratios closely track the water table depth variations, with C29 most abundant during droughts. We also explored the use of D/H ratios in Sphagnum biomarkers as a water-table depth proxy. Compound-specific hydrogen isotope ratio analyses were performed on Sphagnum biomarkers: C23 and C25 alkane and C24 acid. Dry periods are represented in these records by an enrichment of deuterium in these Sphagnum-specific compounds. These events also correlate

  7. Influence of plane bed on the force exerted on a cylinder oscillating in still water

    Energy Technology Data Exchange (ETDEWEB)

    Naeeni, S.T.O. [Tehran Univ., Dept. of Civil Engineering, Tehran (Iran); Narayanan, R. [Universiti Teknologi Malaysia, Faculty of Civil Engineering, Johor Bahru (Malaysia)

    2005-12-01

    The wall pressure field on a cylinder oscillating over a plane bed in still water is reported in this paper. Two gaps between the cylinder and the bed were considered. Pressures on the periphery of the cylinder were measured by a transducer and were found to be essentially repeatable from one cycle to the next. The forces determined from the pressure profiles compare well with those measured directly by a force transducer except significantly at Keulegan-Carpenter number of 15.0. The importance of the plane bed when it is stationary or moving with the cylinder is examined. The significance of the roughness of the bed with respect to the oscillatory forces exerted on the cylinder is also assessed. (Author)

  8. Prospects for very large, sensitive water Cherenkov detectors for proton decay and neutrino oscillations search

    International Nuclear Information System (INIS)

    Cline, D.B.

    1982-01-01

    We discuss the possibility of constructing large water Cherenkov detectors with mass 10 5 to 10 6 tons that would be sensitive to a few hundred MeV - few GeV energy release. The 10 5 ton detector would be suitable for a search for certain proton decay modes whereas the 10 6 ton detector would act as an active shield for the proton decay detector and as a nu/sub e/, nu/sub μ/ and possibly nu/sub tau/ interaction detector. The neutrino physics would include a sensitive search for neutrino oscillations using atmospheric neutrinos. The location of this detector could be in the deep ocean near Hawaii or in a deep trench between Cuba and Haiti or perhaps deep lakes like Superior or Baikal if flexible containers are used

  9. Variable speed control in wells turbine-based oscillating water column devices: optimum rotational speed

    Science.gov (United States)

    Lekube, J.; Garrido, A. J.; Garrido, I.

    2018-03-01

    The effects of climate change and global warming reveal the need to find alternative sources of clean energy. In this sense, wave energy power plants, and in particular Oscillating Water Column (OWC) devices, offer a huge potential of energy harnessing. Nevertheless, the conversion systems have not reached a commercially mature stage yet so as to compete with conventional power plants. At this point, the use of new control methods over the existing technology arises as a doable way to improve the efficiency of the system. Due to the non-uniform response that the turbine shows to the rotational speed variation, the speed control of the turbo-generator may offer a feasible solution for efficiency improvement during the energy conversion. In this context, a novel speed control approach for OWC systems is presented in this paper, demonstrating its goodness and affording promising results when particularized to the Mutriku’s wave power plant.

  10. [Effects of water table manipulation on leaf photosynthesis, morphology and growth of Phragmites australis and Imperata cylindrica in the reclaimed tidal wetland at Dongtan of Chongming Island, China].

    Science.gov (United States)

    Zhong, Qi-Cheng; Wang, Jiang-Tao; Zhou, Jian-Hong; Ou, Qiang; Wang, Kai-Yun

    2014-02-01

    During the growing season of 2011, the leaf photosynthesis, morphological and growth traits of Phragmites australis and Imperata cylindrica were investigated along a gradient of water table (low, medium and high) in the reclaimed tidal wetland at the Dongtan of Chongming Island in the Yangtze Estuary of China. A series of soil factors, i. e., soil temperature, moisture, salinity and inorganic nitrogen content, were also measured. During the peak growing season, leaf photosynthetic capacity of P. australis in the wetland with high water table was significantly lower than those in the wetland with low and medium water tables, and no difference was observed in leaf photosynthetic capacity of I. cylindrica at the three water tables. During the entire growing season, at the shoot level, the morphological and growth traits of P. australis got the optimum in the wetland with medium water table, but most of the morphological and growth traits of I. cylindrica had no significant differences at the three water tables. At the population level, the shoot density, leaf area index and aboveground biomass per unit area were the highest in the wetland with high water table for P. australis, but all of the three traits were the highest in the wetland with low water table for I. cylindrica. At the early growing season, the rhizome biomass of P. australis in the 0-20 cm soil layer had no difference at the three water tables, and the rhizome biomass of I. cylindrica in the 0-20 cm soil layer in the wetland with high water table was significantly lower than those in the wetland with low and medium water table. As a native hygrophyte before the reclamation, the variations of performances of P. australis at the three water tables were probably attributed to the differences in the soil factors as well as the intensity of competition from I. cylindrica. To appropriately manipulate water table in the reclaimed tidal wetland may restrict the growth and propagation of the mesophyte I

  11. Water relations and foliar isotopic composition of Prosopis tamarugo Phil. an endemic tree of the Atacama Desert growing under three levels of water table depth.

    Directory of Open Access Journals (Sweden)

    Marco eGarrido

    2016-03-01

    Full Text Available Prosopis tamarugo Phil. is a strict phreatophyte tree species endemic to the Pampa del Tamarugal, Atacama Desert. The extraction of water for various uses has increased the depth of the water table in the Pampa aquifers threatening its conservation. This study aimed to determine the effect of the groundwater table depth on the water relations of P. tamarugo and to present thresholds of groundwater depth (GWD that can be used in the groundwater management of the P. tamarugo ecosystem. Three levels of GWD, 11.2 ± 0.3 m, 10.3 ± 0.3 m and 7.1 ± 0.1 m, (the last GWD being our reference were selected and groups of 4 individuals per GWD were studied in the months of January and July of the years 2011 through 2014. When the water table depth exceeded 10 m, P. tamarugo had lower pre-dawn and midday water potential but no differences were observed in minimum leaf stomatal resistance when compared to the condition of 7.1 m GWD; the leaf tissue increased its δ13C and δ18O composition. Furthermore, a smaller green canopy fraction of the trees and increased foliage loss in winter with increasing water table depth was observed. The differences observed in the physiological behavior of P. tamarugo trees, attributable to the ground water depth; show that increasing the depth of the water table from 7 to 11 m significantly affects the water status of P. tamarugo. The results indicate that P. tamarugo has an anisohydric stomatal behaviour and that given a reduction in water supply it regulates the water demand via foliage loss. The growth and leaf physiological activities are highly sensitive to GWD. The foliage loss appears to prevent the trees from reaching water potentials leading to complete loss of hydraulic functionality by cavitation. The balance achieved between water supply and demand was reflected in the low variation of the water potential and of the variables related to gas exchange over time for a given GWD. This acclimation capacity of P

  12. Water Relations and Foliar Isotopic Composition of Prosopis tamarugo Phil., an Endemic Tree of the Atacama Desert Growing at Three Levels of Water Table Depth.

    Science.gov (United States)

    Garrido, Marco; Silva, Paola; Acevedo, Edmundo

    2016-01-01

    Prosopis tamarugo Phil. is a strict phreatophyte tree species endemic to the "Pampa del Tamarugal", Atacama Desert. The extraction of water for various uses has increased the depth of the water table in the Pampa aquifers threatening its conservation. This study aimed to determine the effect of the groundwater table depth on the water relations of P. tamarugo and to present thresholds of groundwater depth (GWD) that can be used in the groundwater management of the P. tamarugo ecosystem. Three levels of GWD, 11.2 ± 0.3 m, 10.3 ± 0.3 m, and 7.1 ± 0.1 m, (the last GWD being our reference) were selected and groups of four individuals per GWD were studied in the months of January and July of the years 2011 through 2014. When the water table depth exceeded 10 m, P. tamarugo had lower pre-dawn and mid-day water potential but no differences were observed in minimum leaf stomatal resistance when compared to the condition of 7.1 m GWD; the leaf tissue increased its δ(13)C and δ(18)O composition. Furthermore, a smaller green canopy fraction of the trees and increased foliage loss in winter with increasing water table depth was observed. The differences observed in the physiological behavior of P. tamarugo trees, attributable to the ground water depth; show that increasing the depth of the water table from 7 to 11 m significantly affects the water status of P. tamarugo. The results indicate that P. tamarugo has an anisohydric stomatal behavior and that given a reduction in water supply it regulates the water demand via foliage loss. The growth and leaf physiological activities are highly sensitive to GWD. The foliage loss appears to prevent the trees from reaching water potentials leading to complete loss of hydraulic functionality by cavitation. The balance achieved between water supply and demand was reflected in the low variation of the water potential and of the variables related to gas exchange over time for a given GWD. This acclimation capacity of P. tamarugo after

  13. Nitrogen Release in Pristine and Drained Peat Profiles in Response to Water Table Fluctuations: A Mesocosm Experiment

    Directory of Open Access Journals (Sweden)

    Merjo P. P. Laine

    2013-01-01

    Full Text Available In the northern hemisphere, variability in hydrological conditions was suggested to increase as a consequence of climate warming, which may result in longer droughts than the area has experienced before. Due to their predominately anoxic conditions, peatlands are expected to respond to changes in hydrological conditions, such as successive drying and rewetting periods. As peatlands are rich in organic matter, any major changes in water table may influence the decomposition of it. The hydrological conditions may also influence release of nutrients from peat profiles as well as affect their transport to downstream ecosystems. In our mesocosm experiment, artificial water table fluctuations in pristine peat profiles caused an increase in dissolved organic nitrogen (DON and ammonium (NH4+-N concentrations, while no response was found in drained peat profiles, although originating from the same peatland complex.

  14. Thixotropic Phenomena in Water: Quantitative Indicators of Casimir-Magnetic Transformations from Vacuum Oscillations (Virtual Particles

    Directory of Open Access Journals (Sweden)

    Michael A. Persinger

    2015-09-01

    Full Text Available The ~1.5 × 10−20 J which is considered a universal quantity and is associated with the movement of protons in water also relates to the ratio of the magnetic moment of a proton divided by its unit charge, multiplied by viscosity and applied over the O-H distance. There is quantitative evidence that thixotropy, the “spontaneous” increased viscosity in water when undisturbed, originates from the transformation of virtual particles or vacuum oscillations to real states through conversion of Casimir-magnetic energies that involve the frequency of the neutral hydrogen line and the upper bound threshold value for intergalactic magnetic fields. The results indicate that ½ of a single electron orbit is real (particle and the other ½ is virtual (wave. The matter equivalent per s for virtual-to-real states for electrons in 1 mL of water with a neutral pH is consistent with the numbers of protons (H+ and the measured range of molecules in the coherent domains for both width and duration of growth and is similar to widths of intergalactic dust grains from which planets and stars may condense. The de Broglie momentum for the lower boundary of the width of coherent domains multiplied by the fine structure velocity of an electron is concurrent with the quantum when one proton is being removed from another and when the upper boundary of the rest mass of a photon is transformed by the product of velocities for putative “entanglement” and light. Theoretical and experimental results indicate that components of thixotropy, such as specific domains of intercalated water molecules, could display excess correlations over very large distances. Because the energies of the universal quantity and water converge it may be a special conduit for discrete transformations from virtual to real states.

  15. An analytical study on nested flow systems in a Tóthian basin with a periodically changing water table

    Science.gov (United States)

    Zhao, Ke-Yu; Jiang, Xiao-Wei; Wang, Xu-Sheng; Wan, Li; Wang, Jun-Zhi; Wang, Heng; Li, Hailong

    2018-01-01

    Classical understanding on basin-scale groundwater flow patterns is based on Tóth's findings of a single flow system in a unit basin (Tóth, 1962) and nested flow systems in a complex basin (Tóth, 1963), both of which were based on steady state models. Vandenberg (1980) extended Tóth (1962) by deriving a transient solution under a periodically changing water table in a unit basin and examined the flow field distortion under different dimensionless response time, τ∗. Following Vandenberg's (1980) approach, we extended Tóth (1963) by deriving the transient solution under a periodically changing water table in a complex basin and examined the transient behavior of nested flow systems. Due to the effect of specific storage, the flow field is asymmetric with respect to the midline, and the trajectory of internal stagnation points constitutes a non-enclosed loop, whose width decreases when τ∗ decreases. The distribution of the relative magnitude of hydraulic head fluctuation, Δh∗ , is dependent on the horizontal distance away from a divide and the depth below the land surface. In the shallow part, Δh∗ decreases from 1 at the divide to 0 at its neighboring valley under all τ∗, while in the deep part, Δh∗ reaches a threshold, whose value decreases when τ∗ increases. The zones with flowing wells are also found to change periodically. As water table falls, there is a general trend of shrinkage in the area of zones with flowing wells, which has a lag to the declining water table under a large τ∗. Although fluxes have not been assigned in our model, the recharge/discharge flux across the top boundary can be obtained. This study is critical to understand a series of periodically changing hydrogeological phenomena in large-scale basins.

  16. Discoloration of polyvinyl chloride (PVC) tape as a proxy for water-table depth in peatlands: validation and assessment of seasonal variability

    Science.gov (United States)

    Booth, Robert K.; Hotchkiss, Sara C.; Wilcox, Douglas A.

    2005-01-01

    Summary: 1. Discoloration of polyvinyl chloride (PVC) tape has been used in peatland ecological and hydrological studies as an inexpensive way to monitor changes in water-table depth and reducing conditions. 2. We investigated the relationship between depth of PVC tape discoloration and measured water-table depth at monthly time steps during the growing season within nine kettle peatlands of northern Wisconsin. Our specific objectives were to: (1) determine if PVC discoloration is an accurate method of inferring water-table depth in Sphagnum-dominated kettle peatlands of the region; (2) assess seasonal variability in the accuracy of the method; and (3) determine if systematic differences in accuracy occurred among microhabitats, PVC tape colour and peatlands. 3. Our results indicated that PVC tape discoloration can be used to describe gradients of water-table depth in kettle peatlands. However, accuracy differed among the peatlands studied, and was systematically biased in early spring and late summer/autumn. Regardless of the month when the tape was installed, the highest elevations of PVC tape discoloration showed the strongest correlation with midsummer (around July) water-table depth and average water-table depth during the growing season. 4. The PVC tape discoloration method should be used cautiously when precise estimates are needed of seasonal changes in the water-table.

  17. Quality evaluation of commercially sold table water samples in Michael Okpara University of Agriculture, Umudike, Nigeria and surrounding environments

    Directory of Open Access Journals (Sweden)

    D.O. Okorie

    2015-01-01

    Full Text Available In Michael Okpara University of Agriculture, Umudike, Nigeria (MOUAU and surrounding environments, table water of different brands is commercially hawked by vendors. To the best of our knowledge, there is no scientific documentation on the quality of these water samples. Hence this study which evaluated the quality of different brands of water samples commercially sold in MOUAU and surrounding environments. The physicochemical properties (pH, total dissolved solids (TDS, biochemical oxygen demand (BOD, total hardness, dissolved oxygen, Cl, NO3, ammonium nitrogen (NH3N, turbidity, total suspended solids (TSS, Ca, Mg, Na and K of the water samples as indices of their quality were carried out using standard techniques. Results obtained from this study indicated that most of the chemical constituents of these table water samples commercially sold in Umudike environment conformed to the standards given by the Nigerian Industrial Standard (NIS, World Health Organization (WHO and American Public Health Association (APHA, respectively, while values obtained for ammonium nitrogen in these water samples calls for serious checks on methods of their production and delivery to the end users.

  18. Knowledge base expert system control of spatial xenon oscillations in pressurized water reactors

    International Nuclear Information System (INIS)

    Alten, S.

    1992-01-01

    Nuclear reactor operators are required to pay special attention to spatial xenon oscillations during the load-follow operation of pressurized water reactors. They are expected to observe the axial offset of the core, and to estimate the correct time and amount of necessary control action based on heuristic rules given in axial xenon oscillations are knowledge intensive, and heuristic in nature. An expert system, ACES (Axial offset Control using Expert Systems) is developed to implement a heuristic constant axial offset control procedure to aid reactor operators in increasing the plant reliability by reducing the human error component of the failure probability. ACES is written in a production system language, OPS5, based on the forward chaining algorithm. It samples reactor data with a certain time interval in terms of measurable parameters, such as the power, period, and the axial offset of the core. It then processes the core status utilizing a set of equations which are used in a back of the envelope calculations by domain experts. Heuristic rules of ACES identify the control variable to be used among the full and part length control rods and boron concentration, while a knowledge base is used to determine the amount of control. ACES is designed as a set of generic rules to avoid reducing the system into a set of patterns. Instead ACES evaluates the system, determines the necessary corrective actions in terms of reactivity insertion, and provides this reactivity insertion using the control variables. The amount of control action is determined using a knowledge base which consists of the differential rod worth curves, and the boron reactivity worth of a given reactor. Having the reactor dependent parameters in its knowledge base, ACES is applicable to an arbitrary reactor for axial offset control purposes

  19. Analysis of spurious oscillation modes for the shallow water and Navier-Stokes equations

    Science.gov (United States)

    Walters, R.A.; Carey, G.F.

    1983-01-01

    The origin and nature of spurious oscillation modes that appear in mixed finite element methods are examined. In particular, the shallow water equations are considered and a modal analysis for the one-dimensional problem is developed. From the resulting dispersion relations we find that the spurious modes in elevation are associated with zero frequency and large wave number (wavelengths of the order of the nodal spacing) and consequently are zero-velocity modes. The spurious modal behavior is the result of the finite spatial discretization. By means of an artificial compressibility and limiting argument we are able to resolve the similar problem for the Navier-Stokes equations. The relationship of this simpler analysis to alternative consistency arguments is explained. This modal approach provides an explanation of the phenomenon in question and permits us to deduce the cause of the very complex behavior of spurious modes observed in numerical experiments with the shallow water equations and Navier-Stokes equations. Furthermore, this analysis is not limited to finite element formulations, but is also applicable to finite difference formulations. ?? 1983.

  20. Manipulative lowering of the water table during summer does not affect CO2 emissions and uptake in a fen in Germany.

    Science.gov (United States)

    Muhr, Jan; Höhle, Juliane; Otieno, Dennis O; Borken, Werner

    2011-03-01

    We simulated the effect of prolonged dry summer periods by lowering the water table on three manipulation plots (D(1-3)) in a minerotrophic fen in southeastern Germany in three years (2006-2008). The water table at this site was lowered by drainage and by excluding precipitation; three nonmanipulated control plots (C(1-3)) served as a reference. We found no significant differences in soil respiration (R(Soil)), gross primary production (GPP), or aboveground respiration (R(AG)) between the C(1-3) and D(1-3) plots in any of the measurement years. The water table on the control plots was naturally low, with a median water table (2006-2008) of 8 cm below the surface, and even lower during summer when respiratory activity was highest, with median values (C(1-3)) between 11 and 19 cm below the surface. If it is assumed that oxygen availability in the uppermost 10 cm was not limited by the location of the water table, manipulative lowering of the water table most likely increased oxygen availability only in deeper peat layers where we expect R(Soil) to be limited by poor substrate quality rather than anoxia. This could explain the lack of a manipulation effect. In a second approach, we estimated the influence of the water table on R(Soil) irrespective of treatment. The results showed a significant correlation between R(Soil) and water table, but with R(Soil) decreasing at lower water tables rather than increasing. We thus conclude that decomposition in the litter layer is not limited by waterlogging in summer, and deeper peat layers bear no significant decomposition potential due to poor substrate quality. Consequently, we do not expect enhanced C losses from this site due to increasing frequency of dry summers. Assimilation and respiration of aboveground vegetation were not affected by water table fluctuations between 10 and >60 cm depth, indicating the lack of stress resulting from either anoxia (high water table) or drought (low water table).

  1. Culture of microalgae biomass for valorization of table olive processing water

    Directory of Open Access Journals (Sweden)

    Contreras, C. G.

    2016-09-01

    Full Text Available Table olive processing water (TOPW contains many complex substances, such as phenols, which could be valorized as a substrate for microalgae biomass culture. The aim of this study was to assess the capability of Nannochloropsis gaditana to grow in TOPW at different concentrations (10- 80% in order to valorize this processing water. Within this range, the highest increment of biomass was determined at percentage of 40% of TOPW, reaching an increment of 0.36 ± 0.05 mg volatile suspended solids (VSS/L. Components of algal biomass were similar for the experiments at 10-40% of TOPW, where proteins were the major compounds (56-74%. Total phenols were retained in the microalgae biomass (0.020 ± 0.002 g of total phenols/g VSS. Experiments for 80% of TOPW resulted in a low production of microalgae biomass. High organic matter, nitrogen, phosphorus and phenol removal were achieved in all TOPW concentrations. Although high-value products, such as proteins, were obtained and high removal efficiencies of nutrients were determined, microalgae biomass culture should be enhanced to become a suitable integral processing water treatment.El agua resultante del proceso de elaboración de la aceituna de mesa (TOPW presenta un elevado contenido en sustancias complejas, como fenoles, que podría permitir su uso como sustrato para el cultivo de microalgas. El objetivo de este estudio se centra en evaluar la capacidad de crecimiento de Nannochloropsis gaditana en TOPW a distintas concentraciones (10-80% con vistas a la valorización de estas aguas. El mayor incremento de biomasa se obtuvo para un porcentaje del 40% de TOPW, alcanzando un aumento de 0.36 ± 0.50 mg sólidos en suspensión volátiles (SSV/L. Los componentes presentes en la biomasa han sido similares para los experimentos con 10-40% de TOPW, siendo las proteínas los compuestos mayoritarios en todos los casos (56-74%. Los fenoles totales quedaron retenidos en las microalgas, alcanzando una concentraci

  2. Sliding Mode Control for Pressurized-Water Nuclear Reactors in load following operations with bounded xenon oscillations

    International Nuclear Information System (INIS)

    Ansarifar, G.R.; Saadatzi, S.

    2015-01-01

    Highlights: • We present SMC which is a robust nonlinear controller to control the PWR power. • Xenon oscillations are kept bounded within acceptable limits. • The stability analysis has been based on Lyapunov approach. • Simulation results indicate the high performance of this new control. - Abstract: One of the important operations in nuclear power plants is load-following in which imbalance of axial power distribution induces xenon oscillations. These oscillations must be maintained within acceptable limits otherwise the nuclear power plant could become unstable. Therefore, bounded xenon oscillation considered to be a constraint for the load-following operation. In this paper, sliding mode control (SMC) which is a robust nonlinear controller is designed to control the Pressurized-Water Nuclear Reactor (PWR) power for the load-following operation problem that ensures xenon oscillations are kept bounded within acceptable limits. The proposed controller uses constant axial offset (AO) strategy to maintain xenon oscillations to be bounded. The constant AO is a robust state constraint for load-following problem. The reactor core is simulated based on the two-point nuclear reactor model and one delayed neutron group. The stability analysis is given by means Lyapunov approach, thus the control system is guaranteed to be stable within a large range. The employed method is easy to implement in practical applications and moreover, the sliding mode control exhibits the desired dynamic properties during the entire output-tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness and stability. Results show that the proposed controller for the load-following operation is sufficiently effective so that the xenon oscillations are kept bounded in the considered region

  3. Tables of homogeneous equilibrium critical flow parameters for water in SI units

    International Nuclear Information System (INIS)

    Hall, D.G.; Czapary, L.S.

    1980-09-01

    This reference document presents tables and charts containing data calculated using the homogeneous equilibrium critical flow model (HEM). The ranges of stagnation state properties for which data are presented include: pressures from 2 to 22 120kPa, temperatures from 290 to 640 K, and thermodynamic qualities from 0 to 1

  4. A Mathematical View of Water Table Fluctuations in a Shallow Aquifer in Brazil

    NARCIS (Netherlands)

    Neto, Dagmar C.; Chang, Hung K.; van Genuchten, Martinus Th

    Detailed monitoring of the groundwater table can provide important data about both short- and long-term aquifer processes, including information useful for estimating recharge and facilitating groundwater modeling and remediation efforts. In this paper, we presents results of 4years (2002 to 2005)

  5. Use of well points to determine the thickness and extent of floating product atop the water table

    International Nuclear Information System (INIS)

    Liikala, T.L.; Lewis, R.; Gilmore, T.; Hoffmann, H.

    1994-01-01

    The release of petroleum products to the ground water is a widespread problem. Conventional plume tracking techniques are to drill wells and measure product thickness and extent. In this study, well points were installed to rapidly and inexpensively determine the thickness and extent of floating product atop the water table. Spills and leaks of JP-4 have produced a discrete full layer atop the water table at one site at Eielson Air Force Base near Fairbanks, Alaska. The 0.2- to 1.3-foot-thick layer was identified in two ground water monitoring wells at a depth of approximately 10 feet. The layer is contained within unconsolidated glaciofluvial sands and gravels. A comprehensive assessment of the product thickness and extent was necessary for the site remedial investigation/feasibility study. The emplacement of additional monitoring wells was discouraged because of time and budget constraints. The fuel layer was delineated with 18 screened well points. The points consist of 2-inch-diameter galvanized steel pipe. The points were driven into the floating products with a hollow-stem auger rig sampling hammer. The product thickness was measured with an interface probe. The presence of floating product could be measured immediately after emplacement; the product thickness measurements typically stabilized within three days. The product thickness compared favorably with those measured in adjacent monitoring wells

  6. The effect of urbanization in an arid region: Formation of a perched water table that causes environmental damages

    Science.gov (United States)

    Karnieli, A.; Issar, A.; Wolf, M.

    1984-03-01

    Construction in a new neighborhood in the israeli town of Dimona, situated in an arid region in the south of the country (150 mm average annual rainfall), resulted in a rise in groundwater levels during the subsequent rainy seasons This caused flooding of shelter basements, soil sliding, and sagging which permanently damaged walls and buildings The neighborhood had been built on continental sands and marls blanketed by loess, on a valley slope near a rocky anticlinal dip-slope Subsurface studies, using piezometer holes and groundwater analyses, revealed the presence of sand lenses alternating with plastic marls, which act as seasonal aquifers with perched water tables Groundwaters obtain high SO{4/-2} and Cl- corrosivity through contact with these nonflushed marls of the Neogene valley fill (Hazeva Formation) The reasons for the rising of groundwater were found to be (a) artificial interference with the natural (pre-construction) drainage system—interception of the hillside runoff by building plots, roads, etc, (b) partial denudation of the loess blanket, increasing the local infiltration and the build-up of local, perched water tables, and (c) corrosion of concrete and steel pipelines, as well as foundations, by prolonged contact with corrosive groundwater, resulting in haphazard but massive leakage Guidelines are proposed for an environmental improvement plan, which would include terracing and planting of the watershed above town to increase evapotranspiration, lowering of the water table by pumping, and diverting the water to suburban parks (groves of saltresistant trees), and replacement of steel and cement pipes by a non-corrodable plastic pipe system

  7. A Model Predictive Control-Based Power Converter System for Oscillating Water Column Wave Energy Converters

    Directory of Open Access Journals (Sweden)

    Gimara Rajapakse

    2017-10-01

    Full Text Available Despite the predictability and availability at large scale, wave energy conversion (WEC has still not become a mainstream renewable energy technology. One of the main reasons is the large variations in the extracted power which could lead to instabilities in the power grid. In addition, maintaining the speed of the turbine within optimal range under changing wave conditions is another control challenge, especially in oscillating water column (OWC type WEC systems. As a solution to the first issue, this paper proposes the direct connection of a battery bank into the dc-link of the back-to-back power converter system, thereby smoothening the power delivered to the grid. For the second issue, model predictive controllers (MPCs are developed for the rectifier and the inverter of the back-to-back converter system aiming to maintain the turbine speed within its optimum range. In addition, MPC controllers are designed to control the battery current as well, in both charging and discharging conditions. Operations of the proposed battery direct integration scheme and control solutions are verified through computer simulations. Simulation results show that the proposed integrated energy storage and control solutions are capable of delivering smooth power to the grid while maintaining the turbine speed within its optimum range under varying wave conditions.

  8. Mathematical Modeling of Oscillating Water Columns Wave-Structure Interaction in Ocean Energy Plants

    Directory of Open Access Journals (Sweden)

    Aitor J. Garrido

    2015-01-01

    Full Text Available Oscillating Water Column (OWC-based power take-off systems are one of the potential solutions to the current energy problems arising from the use of nuclear fission and the consumption of fossil fuels. This kind of energy converter turns wave energy into electric power by means of three different stages: firstly wave energy is transformed into pneumatic energy in the OWC chamber, and then a turbine turns it into mechanical energy and finally the turbogenerator module attached to the turbine creates electric power from the rotational mechanical energy. To date, capture chambers have been the least studied part. In this context, this paper presents an analytical model describing the dynamic behavior of the capture chamber, encompassing the wave motion and its interaction with the OWC structure and turbogenerator module. The model is tested for the case of the Mutriku wave power plant by means of experimental results. For this purpose, representative case studies are selected from wave and pressure drop input-output data. The results show an excellent matching rate between the values predicted by the model and the experimental measured data with a small bounded error in all cases, so that the validity of the proposed model is proven.

  9. Developing a Long Short-Term Memory (LSTM) based model for predicting water table depth in agricultural areas

    Science.gov (United States)

    Zhang, Jianfeng; Zhu, Yan; Zhang, Xiaoping; Ye, Ming; Yang, Jinzhong

    2018-06-01

    Predicting water table depth over the long-term in agricultural areas presents great challenges because these areas have complex and heterogeneous hydrogeological characteristics, boundary conditions, and human activities; also, nonlinear interactions occur among these factors. Therefore, a new time series model based on Long Short-Term Memory (LSTM), was developed in this study as an alternative to computationally expensive physical models. The proposed model is composed of an LSTM layer with another fully connected layer on top of it, with a dropout method applied in the first LSTM layer. In this study, the proposed model was applied and evaluated in five sub-areas of Hetao Irrigation District in arid northwestern China using data of 14 years (2000-2013). The proposed model uses monthly water diversion, evaporation, precipitation, temperature, and time as input data to predict water table depth. A simple but effective standardization method was employed to pre-process data to ensure data on the same scale. 14 years of data are separated into two sets: training set (2000-2011) and validation set (2012-2013) in the experiment. As expected, the proposed model achieves higher R2 scores (0.789-0.952) in water table depth prediction, when compared with the results of traditional feed-forward neural network (FFNN), which only reaches relatively low R2 scores (0.004-0.495), proving that the proposed model can preserve and learn previous information well. Furthermore, the validity of the dropout method and the proposed model's architecture are discussed. Through experimentation, the results show that the dropout method can prevent overfitting significantly. In addition, comparisons between the R2 scores of the proposed model and Double-LSTM model (R2 scores range from 0.170 to 0.864), further prove that the proposed model's architecture is reasonable and can contribute to a strong learning ability on time series data. Thus, one can conclude that the proposed model can

  10. Impacts of soil conditioners and water table management on phosphorus loss in tile drainage from a clay loam soil.

    Science.gov (United States)

    Zhang, T Q; Tan, C S; Zheng, Z M; Welacky, T W; Reynolds, W D

    2015-03-01

    Adoption of waste-derived soil conditioners and refined water management can improve soil physical quality and crop productivity of fine-textured soils. However, the impacts of these practices on water quality must be assessed to ensure environmental sustainability. We conducted a study to determine phosphorus (P) loss in tile drainage as affected by two types of soil conditioners (yard waste compost and swine manure compost) and water table management (free drainage and controlled drainage with subirrigation) in a clay loam soil under corn-soybean rotation in a 4-yr period from 1999 to 2003. Tile drainage flows were monitored and sampled on a year-round continuous basis using on-site auto-sampling systems. Water samples were analyzed for dissolved reactive P (DRP), particulate P (PP), and total P (TP). Substantially greater concentrations and losses of DRP, PP, and TP occurred with swine manure compost than with control and yard waste compost regardless of water table management. Compared with free drainage, controlled drainage with subirrigation was an effective way to reduce annual and cumulative losses of DRP, PP, and TP in tile drainage through reductions in flow volume and P concentration with control and yard waste compost but not with swine manure compost. Both DRP and TP concentrations in tile drainage were well above the water quality guideline for P, affirming that subsurface loss of P from fine-textured soils can be one critical source for freshwater eutrophication. Swine manure compost applied as a soil conditioner must be optimized by taking water quality impacts into consideration. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. Estimation of groundwater consumption by phreatophytes using diurnal water table fluctuations: A saturated‐unsaturated flow assessment

    Science.gov (United States)

    Loheide, Steven P.; Butler, James J.; Gorelick, Steven M.

    2005-01-01

    Groundwater consumption by phreatophytes is a difficult‐to‐measure but important component of the water budget in many arid and semiarid environments. Over the past 70 years the consumptive use of groundwater by phreatophytes has been estimated using a method that analyzes diurnal trends in hydrographs from wells that are screened across the water table (White, 1932). The reliability of estimates obtained with this approach has never been rigorously evaluated using saturated‐unsaturated flow simulation. We present such an evaluation for common flow geometries and a range of hydraulic properties. Results indicate that the major source of error in the White method is the uncertainty in the estimate of specific yield. Evapotranspirative consumption of groundwater will often be significantly overpredicted with the White method if the effects of drainage time and the depth to the water table on specific yield are ignored. We utilize the concept of readily available specific yield as the basis for estimation of the specific yield value appropriate for use with the White method. Guidelines are defined for estimating readily available specific yield based on sediment texture. Use of these guidelines with the White method should enable the evapotranspirative consumption of groundwater to be more accurately quantified.

  12. Preliminary phenomena identification and ranking tables for simplified boiling water reactor Loss-of-Coolant Accident scenarios

    International Nuclear Information System (INIS)

    Kroeger, P.G.; Rohatgi, U.S.; Jo, J.H.; Slovik, G.C.

    1998-04-01

    For three potential Loss-of-Coolant Accident (LOCA) scenarios in the General Electric Simplified Boiling Water Reactors (SBWR) a set of Phenomena Identification and Ranking Tables (PIRT) is presented. The selected LOCA scenarios are typical for the class of small and large breaks generally considered in Safety Analysis Reports. The method used to develop the PIRTs is described. Following is a discussion of the transient scenarios, the PIRTs are presented and discussed in detailed and in summarized form. A procedure for future validation of the PIRTs, to enhance their value, is outlined. 26 refs., 25 figs., 44 tabs

  13. Estimating the water table under the Radioactive Waste Management Site in Area 5 of the Nevada Test Site: The Dupuit-Forcheimer approximation

    International Nuclear Information System (INIS)

    Lindstrom, F.T.; Barker, L.E.; Cawlfield, D.E.; Daffern, D.D.; Dozier, B.L.; Emer, D.F.; Strong, W.R.

    1992-01-01

    To adequately manage the low level nuclear waste (LLW) repository in Area 5 of the Nevada Test Site (NTS), a knowledge of the water table under the site is paramount. The estimated thickness of the arid intermountain basin alluvium is roughly 900 feet. Very little reliable water table data for Area 5 currently exists. The Special Projects Section of the Reynolds Electrical ampersand Engineering Co., Inc. Waste Management Department is currently formulating a long-range drilling and sampling plan in support of a Resource Conservation Recovery Act (RCRA) Part B permit waiver for groundwater monitoring and liner systems. An estimate of the water table under the LLW repository, called the Radioactive Waste Management Site (RWMS) in Area 5, is needed for the drilling and sampling plan. Very old water table elevation estimates at about a dozen widely scattered test drill holes, as well as water wells, are available from declassified US Geological Survey, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory drilling logs. A three-dimensional steady-state water-flow equation for estimating the water table elevation under a thick, very dry vadose zone is developed using the Dupuit assumption. A prescribed positive vertical downward infiltration/evaporation condition is assumed at the atmosphere/soil interface. An approximation to the square of the elevation head, based upon multivariate cubic interpolation methods, is introduced. The approximate is forced to satisfy the governing elliptic (Poisson) partial differential equation over the domain of definition. The remaining coefficients are determined by interpolating the water table at eight ''boundary point.'' Several realistic scenarios approximating the water table under the RWMS in Area 5 of the NTS are discussed

  14. Skylab fluid mechanics simulations: Oscillation, rotation, collision and coalescence of water droplets under low-gravity environment

    Science.gov (United States)

    Vaughan, O. H., Jr.; Hung, R. J.

    1975-01-01

    Skylab 4 crew members performed a series of demonstrations showing the oscillations, rotations, as well as collision coalescence of water droplets which simulate various physical models of fluids under low gravity environment. The results from Skylab demonstrations provide information and illustrate the potential of an orbiting space-oriented research laboratory for the study of more sophisticated fluid mechanic experiments. Experiments and results are discussed.

  15. Groundwater in the Boreal Plains: How Climate and Geology Interact to Control Water Table Configurations in a Sub-Humid, Low-Relief Region

    Science.gov (United States)

    Hokanson, K. J.; Devito, K.; Mendoza, C. A.

    2017-12-01

    The Boreal Plain (BP) region of Canada, a landscape characterized by low-relief, a sub-humid climate and heterogeneous glacial landforms, is experiencing unprecedented anthropogenic and natural disturbance, including climate change and oil & gas operations. Understanding the controls on and the natural variability of water table position, and subsequently predicting changes in water table position under varying physical and climatic scenarios will become important as water security becomes increasingly threatened. The BP is composed of a mosaic of forestland, wetland, and aquatic land covers that contrast in dominant vegetation cover, evapotranspiration, and soil storage that, in turn, influence water table configurations. Additionally, these land-covers overlie heterogeneous glacial landforms with large contrasts in storage and hydraulic properties which, when coupled with wet-dry climate cycles, result in complex water table distributions in time and space. Several forestland-wetland-pond complexes were selected at the Utikuma Research Study Area (URSA) over three distinct surficial geologic materials (glacial fluvial outwash, stagnant ice moraine, lacustrine clay plain) to explore the roles of climate (cumulative departure from the long term yearly mean precipitation), geology, topographic position, and land cover on water table configurations over 15 years (2002 - 2016). In the absence of large groundwater flow systems, local relief and shallow low conductivity substrates promote the formation of near-surface water tables that are less susceptible to climate variation, regardless of topography. Furthermore, in areas of increased storage, wet and dry climate conditions can result in appreciably different water table configurations over time, ranging from mounds to hydraulic depressions, depending on the arrangement of land-covers, dominant surficial geology, and substrate layering.

  16. Rapid response of hydrological loss of DOC to water table drawdown and warming in Zoige peatland: results from a mesocosm experiment.

    Science.gov (United States)

    Lou, Xue-Dong; Zhai, Sheng-Qiang; Kang, Bing; Hu, Ya-Lin; Hu, Li-Le

    2014-01-01

    A large portion of the global carbon pool is stored in peatlands, which are sensitive to a changing environment conditions. The hydrological loss of dissolved organic carbon (DOC) is believed to play a key role in determining the carbon balance in peatlands. Zoige peatland, the largest peat store in China, is experiencing climatic warming and drying as well as experiencing severe artificial drainage. Using a fully crossed factorial design, we experimentally manipulated temperature and controlled the water tables in large mesocosms containing intact peat monoliths. Specifically, we determined the impact of warming and water table position on the hydrological loss of DOC, the exported amounts, concentrations and qualities of DOC, and the discharge volume in Zoige peatland. Our results revealed that of the water table position had a greater impact on DOC export than the warming treatment, which showed no interactive effects with the water table treatment. Both DOC concentration and discharge volume were significantly increased when water table drawdown, while only the DOC concentration was significantly promoted by warming treatment. Annual DOC export was increased by 69% and 102% when the water table, controlled at 0 cm, was experimentally lowered by -10 cm and -20 cm. Increases in colored and aromatic constituents of DOC (measured by Abs(254 nm), SUVA(254 nm), Abs(400 nm), and SUVA(400 nm)) were observed under the lower water tables and at the higher peat temperature. Our results provide an indication of the potential impacts of climatic change and anthropogenic drainage on the carbon cycle and/or water storage in a peatland and simultaneously imply the likelihood of potential damage to downstream ecosystems. Furthermore, our results highlight the need for local protection and sustainable development, as well as suggest that more research is required to better understand the impacts of climatic change and artificial disturbances on peatland degradation.

  17. Rapid response of hydrological loss of DOC to water table drawdown and warming in Zoige peatland: results from a mesocosm experiment.

    Directory of Open Access Journals (Sweden)

    Xue-Dong Lou

    Full Text Available A large portion of the global carbon pool is stored in peatlands, which are sensitive to a changing environment conditions. The hydrological loss of dissolved organic carbon (DOC is believed to play a key role in determining the carbon balance in peatlands. Zoige peatland, the largest peat store in China, is experiencing climatic warming and drying as well as experiencing severe artificial drainage. Using a fully crossed factorial design, we experimentally manipulated temperature and controlled the water tables in large mesocosms containing intact peat monoliths. Specifically, we determined the impact of warming and water table position on the hydrological loss of DOC, the exported amounts, concentrations and qualities of DOC, and the discharge volume in Zoige peatland. Our results revealed that of the water table position had a greater impact on DOC export than the warming treatment, which showed no interactive effects with the water table treatment. Both DOC concentration and discharge volume were significantly increased when water table drawdown, while only the DOC concentration was significantly promoted by warming treatment. Annual DOC export was increased by 69% and 102% when the water table, controlled at 0 cm, was experimentally lowered by -10 cm and -20 cm. Increases in colored and aromatic constituents of DOC (measured by Abs(254 nm, SUVA(254 nm, Abs(400 nm, and SUVA(400 nm were observed under the lower water tables and at the higher peat temperature. Our results provide an indication of the potential impacts of climatic change and anthropogenic drainage on the carbon cycle and/or water storage in a peatland and simultaneously imply the likelihood of potential damage to downstream ecosystems. Furthermore, our results highlight the need for local protection and sustainable development, as well as suggest that more research is required to better understand the impacts of climatic change and artificial disturbances on peatland degradation.

  18. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips - Part 1: nonuniform infiltration and soil water redistribution

    Science.gov (United States)

    Muñoz-Carpena, Rafael; Lauvernet, Claire; Carluer, Nadia

    2018-01-01

    Vegetation buffers like vegetative filter strips (VFSs) are often used to protect water bodies from surface runoff pollution from disturbed areas. Their typical placement in floodplains often results in the presence of a seasonal shallow water table (WT) that can decrease soil infiltration and increase surface pollutant transport during a rainfall-runoff event. Simple and robust components of hydrological models are needed to analyze the impacts of WT in the landscape. To simulate VFS infiltration under realistic rainfall conditions with WT, we propose a generic infiltration solution (Shallow Water table INfiltration algorithm: SWINGO) based on a combination of approaches by Salvucci and Entekhabi (1995) and Chu (1997) with new integral formulae to calculate singular times (time of ponding, shift time, and time to soil profile saturation). The algorithm was tested successfully on five distinct soils, both against Richards's numerical solution and experimental data in terms of infiltration and soil moisture redistribution predictions, and applied to study the combined effects of varying WT depth, soil type, and rainfall intensity and duration. The results show the robustness of the algorithm and its ability to handle various soil hydraulic functions and initial nonponding conditions under unsteady rainfall. The effect of a WT on infiltration under ponded conditions was found to be effectively decoupled from surface infiltration and excess runoff processes for depths larger than 1.2 to 2 m, being shallower for fine soils and shorter events. For nonponded initial conditions, the influence of WT depth also varies with rainfall intensity. Also, we observed that soils with a marked air entry (bubbling pressure) exhibit a distinct behavior with WT near the surface. The good performance, robustness, and flexibility of SWINGO supports its broader use to study WT effects on surface runoff, infiltration, flooding, transport, ecological, and land use processes. SWINGO is

  19. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips – Part 1: nonuniform infiltration and soil water redistribution

    Directory of Open Access Journals (Sweden)

    R. Muñoz-Carpena

    2018-01-01

    Full Text Available Vegetation buffers like vegetative filter strips (VFSs are often used to protect water bodies from surface runoff pollution from disturbed areas. Their typical placement in floodplains often results in the presence of a seasonal shallow water table (WT that can decrease soil infiltration and increase surface pollutant transport during a rainfall-runoff event. Simple and robust components of hydrological models are needed to analyze the impacts of WT in the landscape. To simulate VFS infiltration under realistic rainfall conditions with WT, we propose a generic infiltration solution (Shallow Water table INfiltration algorithm: SWINGO based on a combination of approaches by Salvucci and Entekhabi (1995 and Chu (1997 with new integral formulae to calculate singular times (time of ponding, shift time, and time to soil profile saturation. The algorithm was tested successfully on five distinct soils, both against Richards's numerical solution and experimental data in terms of infiltration and soil moisture redistribution predictions, and applied to study the combined effects of varying WT depth, soil type, and rainfall intensity and duration. The results show the robustness of the algorithm and its ability to handle various soil hydraulic functions and initial nonponding conditions under unsteady rainfall. The effect of a WT on infiltration under ponded conditions was found to be effectively decoupled from surface infiltration and excess runoff processes for depths larger than 1.2 to 2 m, being shallower for fine soils and shorter events. For nonponded initial conditions, the influence of WT depth also varies with rainfall intensity. Also, we observed that soils with a marked air entry (bubbling pressure exhibit a distinct behavior with WT near the surface. The good performance, robustness, and flexibility of SWINGO supports its broader use to study WT effects on surface runoff, infiltration, flooding, transport, ecological, and land use processes

  20. Spatial variation of nitrogen pollution of the water table at Oued M'Zab (Northern Algerian Sahara)

    Science.gov (United States)

    Benhedid, H.; Bouhoun, M. Daddi

    2018-05-01

    The aim of our work is the study of spatial variations of the water table pollution of Oued M'Zab, in order to determine their abilities of use and the posed problems of degradation. The methodological approach we adopted is to make a spatial study of the variability of nitrogen pollution, as well as to classify water quality according to international standards. The main results obtained in this research show that NH4+ range from 0 to 0,143 mg.l-1 with an average of 0,048 ± 0,039 mg.l-1, the NO2- from 0 to 0,209 mg.l-1 give an average of 0,007 ± 0,033 mg.l-1, and the NO3- vary between 14,264 and 143,465 mg.l-1, with a mean value 54,594 ± 30,503 mg.l-1. According to W.H.O. standards, the majority of these waters are classified as polluted and not drinkable. Our research shows a degradation of the underground water resources in M'Zab Valley. It resulted that it is essential to regulate the use of water and set out other adjustments in order to safeguard the underground water resources so as to promote sustainable development in the valley of M'Zab.

  1. Effect of vegetation removal and water table drawdown on the non-methane biogenic volatile organic compound emissions in boreal peatland microcosms

    Science.gov (United States)

    Faubert, Patrick; Tiiva, Päivi; Rinnan, Åsmund; Räty, Sanna; Holopainen, Jarmo K.; Holopainen, Toini; Rinnan, Riikka

    2010-11-01

    Biogenic volatile organic compound (BVOC) emissions are important in the global atmospheric chemistry and their feedbacks to global warming are uncertain. Global warming is expected to trigger vegetation changes and water table drawdown in boreal peatlands, such changes have only been investigated on isoprene emission but never on other BVOCs. We aimed at distinguishing the BVOCs released from vascular plants, mosses and peat in hummocks (dry microsites) and hollows (wet microsites) of boreal peatland microcosms maintained in growth chambers. We also assessed the effect of water table drawdown (-20 cm) on the BVOC emissions in hollow microcosms. BVOC emissions were measured from peat samples underneath the moss surface after the 7-week-long experiment to investigate whether the potential effects of vegetation and water table drawdown were shown. BVOCs were sampled using a conventional chamber method, collected on adsorbent and analyzed with GC-MS. In hummock microcosms, vascular plants increased the monoterpene emissions compared with the treatment where all above-ground vegetation was removed while no effect was detected on the sesquiterpenes, other reactive VOCs (ORVOCs) and other VOCs. Peat layer from underneath the surface with intact vegetation had the highest sesquiterpene emissions. In hollow microcosms, intact vegetation had the highest sesquiterpene emissions. Water table drawdown decreased monoterpene and other VOC emissions. Specific compounds could be closely associated to the natural/lowered water tables. Peat layer from underneath the surface of hollows with intact vegetation had the highest emissions of monoterpenes, sesquiterpenes and ORVOCs whereas water table drawdown decreased those emissions. The results suggest that global warming would change the BVOC emission mixtures from boreal peatlands following changes in vegetation composition and water table drawdown.

  2. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips - Part 2: model coupling, application, factor importance, and uncertainty

    Science.gov (United States)

    Lauvernet, Claire; Muñoz-Carpena, Rafael

    2018-01-01

    Vegetative filter strips are often used for protecting surface waters from pollution transferred by surface runoff in agricultural watersheds. In Europe, they are often prescribed along the stream banks, where a seasonal shallow water table (WT) could decrease the buffer zone efficiency. In spite of this potentially important effect, there are no systematic experimental or theoretical studies on the effect of this soil boundary condition on the VFS efficiency. In the companion paper (Muñoz-Carpena et al., 2018), we developed a physically based numerical algorithm (SWINGO) that allows the representation of soil infiltration with a shallow water table. Here we present the dynamic coupling of SWINGO with VFSMOD, an overland flow and transport mathematical model to study the WT influence on VFS efficiency in terms of reductions of overland flow, sediment, and pesticide transport. This new version of VFSMOD was applied to two contrasted benchmark field studies in France (sandy-loam soil in a Mediterranean semicontinental climate, and silty clay in a temperate oceanic climate), where limited testing of the model with field data on one of the sites showed promising results. The application showed that for the conditions of the studies, VFS efficiency decreases markedly when the water table is 0 to 1.5 m from the surface. In order to evaluate the relative importance of WT among other input factors controlling VFS efficiency, global sensitivity and uncertainty analysis (GSA) was applied on the benchmark studies. The most important factors found for VFS overland flow reduction were saturated hydraulic conductivity and WT depth, added to sediment characteristics and VFS dimensions for sediment and pesticide reductions. The relative importance of WT varied as a function of soil type (most important at the silty-clay soil) and hydraulic loading (rainfall + incoming runoff) at each site. The presence of WT introduced more complex responses dominated by strong interactions in

  3. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips – Part 2: model coupling, application, factor importance, and uncertainty

    Directory of Open Access Journals (Sweden)

    C. Lauvernet

    2018-01-01

    Full Text Available Vegetative filter strips are often used for protecting surface waters from pollution transferred by surface runoff in agricultural watersheds. In Europe, they are often prescribed along the stream banks, where a seasonal shallow water table (WT could decrease the buffer zone efficiency. In spite of this potentially important effect, there are no systematic experimental or theoretical studies on the effect of this soil boundary condition on the VFS efficiency. In the companion paper (Muñoz-Carpena et al., 2018, we developed a physically based numerical algorithm (SWINGO that allows the representation of soil infiltration with a shallow water table. Here we present the dynamic coupling of SWINGO with VFSMOD, an overland flow and transport mathematical model to study the WT influence on VFS efficiency in terms of reductions of overland flow, sediment, and pesticide transport. This new version of VFSMOD was applied to two contrasted benchmark field studies in France (sandy-loam soil in a Mediterranean semicontinental climate, and silty clay in a temperate oceanic climate, where limited testing of the model with field data on one of the sites showed promising results. The application showed that for the conditions of the studies, VFS efficiency decreases markedly when the water table is 0 to 1.5 m from the surface. In order to evaluate the relative importance of WT among other input factors controlling VFS efficiency, global sensitivity and uncertainty analysis (GSA was applied on the benchmark studies. The most important factors found for VFS overland flow reduction were saturated hydraulic conductivity and WT depth, added to sediment characteristics and VFS dimensions for sediment and pesticide reductions. The relative importance of WT varied as a function of soil type (most important at the silty-clay soil and hydraulic loading (rainfall + incoming runoff at each site. The presence of WT introduced more complex responses dominated by strong

  4. Estimating the water table under the Radioactive Waste Management Site in Area 5 of the Nevada Test Site the Dupuit-Forcheimer approximation

    International Nuclear Information System (INIS)

    Lindstrom, T.F.; Barker, L.E.; Cawlfield, D.E.; Daffern, D.D.; Dozier, B.L.; Emer, D.F.; Strong, W.R.

    1992-01-01

    A two-dimensional steady-state water-flow equation for estimating the water table elevation under a thick, very dry vadose zone is developed and discussed. The Dupuit assumption is made. A prescribed downward vertical infiltration/evaporation condition is assumed at the atmosphere-soil interface. An approximation to the square of the elevation head, based upon multivariate cubic interpolation methods, is introduced. The approximation is forced to satisfy the governing elliptic (Poisson) partial differential equation over the domain of definition. The remaining coefficients are determined by interpolating the water table at eight ''boundary points.'' Several realistic scenarios approximating the water table under the Radioactive Waste Management Site (RWMS) in Area 5 of the Nevada Test Site (NTS) are discussed

  5. Analysis of Tide and Offshore Storm-Induced Water Table Fluctuations for Structural Characterization of a Coastal Island Aquifer

    Science.gov (United States)

    Trglavcnik, Victoria; Morrow, Dean; Weber, Kela P.; Li, Ling; Robinson, Clare E.

    2018-04-01

    Analysis of water table fluctuations can provide important insight into the hydraulic properties and structure of a coastal aquifer system including the connectivity between the aquifer and ocean. This study presents an improved approach for characterizing a permeable heterogeneous coastal aquifer system through analysis of the propagation of the tidal signal, as well as offshore storm pulse signals through a coastal aquifer. Offshore storms produce high wave activity, but are not necessarily linked to significant onshore precipitation. In this study, we focused on offshore storm events during which no onshore precipitation occurred. Extensive groundwater level data collected on a sand barrier island (Sable Island, NS, Canada) show nonuniform discontinuous propagation of the tide and offshore storm pulse signals through the aquifer with isolated inland areas showing enhanced response to both oceanic forcing signals. Propagation analysis suggests that isolated inland water table fluctuations may be caused by localized leakage from a confined aquifer that is connected to the ocean offshore but within the wave setup zone. Two-dimensional groundwater flow simulations were conducted to test the leaky confined-unconfined aquifer conceptualization and to identify the effect of key parameters on tidal signal propagation in leaky confined-unconfined coastal aquifers. This study illustrates that analysis of offshore storm signal propagation, in addition to tidal signal propagation, provides a valuable and low resource approach for large-scale characterization of permeable heterogeneous coastal aquifers. Such an approach is needed for the effective management of coastal environments where water resources are threatened by human activities and the changing climate.

  6. Numerical analysis of regular waves over an onshore oscillating water column

    Energy Technology Data Exchange (ETDEWEB)

    Davyt, D.P.; Teixeira, P.R.F. [Universidade Federal do Rio Grande (FURG), RS (Brazil)], E-mail: pauloteixeira@furg.br; Ramalhais, R. [Universidade Nova de Lisboa, Caparica (Portugal). Fac. de Ciencias e Tecnologia; Didier, E. [Laboratorio Nacional de Engenharia Civil, Lisboa (Portugal)], E-mail: edidier@lnec.pt

    2010-07-01

    The potential of wave energy along coastal areas is a particularly attractive option in regions of high latitude, such as the coasts of northern Europe, North America, New Zealand, Chile and Argentina where high densities of annual average wave energy are found (typically between 40 and 100 kW/m of wave front). Power estimated in the south of Brazil is 30kW/m, creating a possible alternative of source energy in the region. There are many types and designs of equipment to capture energy from waves under analysis, such as the oscillating water column type (OWC) which has been one of the first to be developed and installed at sea. Despite being one of the most analyzed wave energy converter devices, there are few case studies using numerical simulation. In this context, the numerical analysis of regular waves over an onshore OWC is the main objective of this paper. The numerical models FLUINCO and FLUENT are used for achieving this goal. The FLUINCO model is based on RANS equations which are discretized using the two-step semi-implicit Taylor-Galerkin method. An arbitrary Lagrangian Eulerian formulation is used to enable the solution of problems involving free surface movements. The FLUENT code (version 6.3.26) is based on the finite volume method to solve RANS equations. Volume of Fluid method (VOF) is used for modeling free surface flows. Time integration is achieved by a second order implicit scheme, momentum equations are discretized using MUSCL scheme and HRIC (High Resolution Interface Capturing) scheme is used for convective term of VOF transport equation. The case study consists of a 10.m deep channel with a 10 m wide chamber at its end. One meter high waves with different periods are simulated. Comparisons between FLUINCO and FLUENT results are presented. Free surface elevation inside the chamber; velocity distribution and streamlines; amplification factor (relation between wave height inside the chamber and incident wave height); phase angle (angular

  7. Evaporation from bare ground with different water-table depths based on an in-situ experiment in Ordos Plateau, China

    Science.gov (United States)

    Zhang, Zaiyong; Wang, Wenke; Wang, Zhoufeng; Chen, Li; Gong, Chengcheng

    2018-03-01

    The dynamic processes of ground evaporation are complex and are related to a multitude of factors such as meteorological influences, water-table depth, and materials in the unsaturated zone. To investigate ground evaporation from a homogeneous unsaturated zone, an in-situ experiment was conducted in Ordos Plateau of China. Two water-table depths were chosen to explore the water movement in the unsaturated zone and ground evaporation. Based on the experimental and calculated results, it was revealed that (1) bare ground evaporation is an atmospheric-limited stage for the case of water-table depth being close to the capillary height; (2) the bare ground evaporation is a water-storage-limited stage for the case of water-table depth being beyond the capillary height; (3) groundwater has little effect on ground-surface evaporation when the water depth is larger than the capillary height; and (4) ground evaporation is greater at nighttime than that during the daytime; and (5) a liquid-vapor interaction zone at nearly 20 cm depth is found, in which there exists a downward vapor flux on sunny days, leading to an increasing trend of soil moisture between 09:00 to 17:00; the maximum value is reached at midday. The results of this investigation are useful to further understand the dynamic processes of ground evaporation in arid areas.

  8. Effect of agroforestry system on yield attributes of wheat (Triticum Aestivum l.) under shallow water table conditions

    International Nuclear Information System (INIS)

    Kiran, R.; Agnihotri, A.K.

    2001-01-01

    Fifteen tree rows of Eucalyptus tereticornis were planted at G.B.Pant University of Agriculture and Technology, Pant Nagar, located in tarai region of Uttaranchal in a Nelder fan design in March 1989 at the angle of 24øN' from each other starting from north in anticlockwise direction. Area per tree was 30 m 2 . Wheat was intercropped with Eucalyptus tereticornis of 21st November, 1996. Each row of trees was one treatment. There were 15 treatments with control as sole crop. Various yield attributes, net radiation and water table depth were measured below trees and in control, simultaneously. In treatments 7, 8, 9, 10 and 12 early vegetative growth was observed below trees. Higher yield attributing characters were also observed in some of the treatments below trees. In general, treatment 9 (192-216ø) gave better yield attributes than that of control

  9. Creation of Soil Water and Physical data base and its inclusion in a new version of GIS of Soil Resources Attributive Table

    International Nuclear Information System (INIS)

    Kolev, Boyko

    2013-01-01

    For better using of GIS of Soil Resources a new version of the attributive table formation was created. This makes possible soil, physical, and water properties to be included into the table. The simulation procedure for soil hydro-physical properties determination was realized by using the soil particle size distribution data only. This develops a calculation algorithm for soil water content dynamic monitoring, which was realized for some of Bulgarian soils. The main aims of the study are: To demonstrate the usefulness of the new version of the attributive table formation. To show how the simulation model can be applied for environment conditions monitoring and agricultural production management. Keywords: environment conditions, simulation model, soil moisture at field capacity, wilting point, effective soil water content, particle size distribution

  10. A decade of boreal rich fen greenhouse gas fluxes in response to natural and experimental water table variability

    Science.gov (United States)

    Olefeldt, David; Euskirchen, Eugénie S.; Harden, Jennifer W.; Kane, Evan S.; McGuire, A. David; Waldrop, Mark P.; Turetsky, Merritt R.

    2017-01-01

    Rich fens are common boreal ecosystems with distinct hydrology, biogeochemistry and ecology that influence their carbon (C) balance. We present growing season soil chamber methane emission (FCH4), ecosystem respiration (ER), net ecosystem exchange (NEE) and gross primary production (GPP) fluxes from a 9-years water table manipulation experiment in an Alaskan rich fen. The study included major flood and drought years, where wetting and drying treatments further modified the severity of droughts. Results support previous findings from peatlands that drought causes reduced magnitude of growing season FCH4, GPP and NEE, thus reducing or reversing their C sink function. Experimentally exacerbated droughts further reduced the capacity for the fen to act as a C sink by causing shifts in vegetation and thus reducing magnitude of maximum growing season GPP in subsequent flood years by ~15% compared to control plots. Conversely, water table position had only a weak influence on ER, but dominant contribution to ER switched from autotrophic respiration in wet years to heterotrophic in dry years. Droughts did not cause inter-annual lag effects on ER in this rich fen, as has been observed in several nutrient-poor peatlands. While ER was dependent on soil temperatures at 2 cm depth, FCH4 was linked to soil temperatures at 25 cm. Inter-annual variability of deep soil temperatures was in turn dependent on wetness rather than air temperature, and higher FCH4 in flooded years was thus equally due to increased methane production at depth and decreased methane oxidation near the surface. Short-term fluctuations in wetness caused significant lag effects on FCH4, but droughts caused no inter-annual lag effects on FCH4. Our results show that frequency and severity of droughts and floods can have characteristic effects on the exchange of greenhouse gases, and emphasize the need to project future hydrological regimes in rich fens.

  11. Gas exchange patterns and water loss rates in the Table Mountain cockroach, Aptera fusca (Blattodea: Blaberidae).

    Science.gov (United States)

    Groenewald, Berlizé; Bazelet, Corinna S; Potter, C Paige; Terblanche, John S

    2013-10-15

    The importance of metabolic rate and/or spiracle modulation for saving respiratory water is contentious. One major explanation for gas exchange pattern variation in terrestrial insects is to effect a respiratory water loss (RWL) saving. To test this, we measured the rates of CO2 and H2O release ( and , respectively) in a previously unstudied, mesic cockroach, Aptera fusca, and compared gas exchange and water loss parameters among the major gas exchange patterns (continuous, cyclic, discontinuous gas exchange) at a range of temperatures. Mean , and per unit did not differ among the gas exchange patterns at all temperatures (P>0.09). There was no significant association between temperature and gas exchange pattern type (P=0.63). Percentage of RWL (relative to total water loss) was typically low (9.79±1.84%) and did not differ significantly among gas exchange patterns at 15°C (P=0.26). The method of estimation had a large impact on the percentage of RWL, and of the three techniques investigated (traditional, regression and hyperoxic switch), the traditional method generally performed best. In many respects, A. fusca has typical gas exchange for what might be expected from other insects studied to date (e.g. , , RWL and cuticular water loss). However, we found for A. fusca that expressed as a function of metabolic rate was significantly higher than the expected consensus relationship for insects, suggesting it is under considerable pressure to save water. Despite this, we found no consistent evidence supporting the conclusion that transitions in pattern type yield reductions in RWL in this mesic cockroach.

  12. Isotopic fractionation of soil water during the evaporation process in the presence of a phreatic water table

    International Nuclear Information System (INIS)

    Leopoldo, P.R.; Stolf, R.

    1979-01-01

    This experiment was conducted with columns of soil, constitued by alluvion sediment keeping a phreatic watertable at a depth of 40 cm and constant water supply, and its objective was to check the water behaviour as to its deuterium and oxigen content when moving from the lower layers to the upper layers, and consequent loss to the atmosphere through evaporation. It was noted that the existing D and 18 O content in the water forming the phreativ watertable practivally does not vary with this process. In addition to the observations on soil columns, soil water from the Brasilian northeastern region was collected and analysed. The phreatic watertable at the collecting site lay at a depth of about 40-50 cm. Preliminarily, it was noted that these results apparently indicate an excess evaporation, and are also consistent with those obtained by other investigators, who proposed the use of stable isotopes to study problems related to salinization of water in this region. (Author) [pt

  13. Methane transport and emissions from soil as affected by water table and vascular plants

    OpenAIRE

    Bhullar, Gurbir S; Iravani, Majid; Edwards, Peter J; Olde Venterink, Harry

    2013-01-01

    Background: The important greenhouse gas (GHG) methane is produced naturally in anaerobic wetland soils. By affecting the production, oxidation and transport of methane to the atmosphere, plants have a major influence upon the quantities emitted by wetlands. Different species and functional plant groups have been shown to affect these processes differently, but our knowledge about how these effects are influenced by abiotic factors such as water regime and temperature remains limited. Here...

  14. SIMULATION OF THE BEHAVIOR OF THE WATER TABLE IN A COASTAL AQUIFER SYSTEM FINITE ELEMENT

    Directory of Open Access Journals (Sweden)

    Luis Lara Romero

    2016-06-01

    Full Text Available This paper presents the application of Galerkin method to discretize the model equation of groundwater ow in a conned aquifer semipermeable with tidal boundary conditions on one of its borders, the other borders remain constant. For the simulations was generated a numerical program, Ground Water Finite Element Method, which implements the method of nite elements with triangular elements with three nodes and a degree of freedom per node.

  15. Environmental Monitoring, Water Quality - MO 2009 Water Quality Standards - Table G Lake Classifications and Use Designations (SHP)

    Data.gov (United States)

    NSGIC State | GIS Inventory — This data set contains Missouri Water Quality Standards (WQS) lake classifications and use designations described in the Missouri Code of State Regulations (CSR), 10...

  16. Effect of the spatial distribution of physical aquifer properties on modelled water table depth and stream discharge in a headwater catchment

    Directory of Open Access Journals (Sweden)

    C. Gascuel-Odoux

    2010-07-01

    Full Text Available Water table depth and its dynamics on hillslopes are often poorly predicted despite they control both water transit time within the catchment and solute fluxes at the catchment outlet. This paper analyses how relaxing the assumption of lateral homogeneity of physical properties can improve simulations of water table depth and dynamics. Four different spatial models relating hydraulic conductivity to topography have been tested: a simple linear relationship, a linear relationship with two different topographic indexes, two Ks domains with a transitional area. The Hill-Vi model has been modified to test these hypotheses. The studied catchment (Kervidy-Naizin, Western France is underlain by schist crystalline bedrock. A shallow and perennial groundwater highly reactive to rainfall events mainly develops in the weathered saprolite layer. The results indicate that (1 discharge and the water table in the riparian zone are similarly predicted by the four models, (2 distinguishing two Ks domains constitutes the best model and slightly improves prediction of the water table upslope, and (3 including spatial variations in the other parameters such as porosity or rate of hydraulic conductivity decrease with depth does not improve the results. These results underline the necessity of better investigations of upslope areas in hillslope hydrology.

  17. Water Table Management Reduces Tile Nitrate Loss in Continuous Corn and in a Soybean-Corn Rotation

    Directory of Open Access Journals (Sweden)

    Craig F. Drury

    2001-01-01

    Full Text Available Water table management systems can be designed to alleviate soil water excesses and deficits, as well as reduce nitrate leaching losses in tile discharge. With this in mind, a standard tile drainage (DR system was compared over 8 years (1991 to 1999 to a controlled tile drainage/subirrigation (CDS system on a low-slope (0.05 to 0.1% Brookston clay loam soil (Typic Argiaquoll in southwestern Ontario, Canada. In the CDS system, tile discharge was controlled to prevent excessive drainage, and water was pumped back up the tile lines (subirrigation to replenish the crop root zone during water deficit periods. In the first phase of the study (1991 to 1994, continuous corn (Zea mays, L. was grown with annual nitrogen (N fertilizer inputs as per local soil test recommendations. In the second phase (1995 to 1999, a soybean (Glycine max L., Merr.-corn rotation was used with N fertilizer added only during the two corn years. In Phase 1 when continuous corn was grown, CDS reduced total tile discharge by 26% and total nitrate loss in tile discharge by 55%, compared to DR. In addition, the 4-year flow weighted mean (FWM nitrate concentration in tile discharge exceeded the Canadian drinking water guideline (10 mg N l–1 under DR (11.4 mg N l–1, but not under CDS (7.0 mg N l–1. In Phase 2 during the soybean-corn rotation, CDS reduced total tile discharge by 38% and total nitrate loss in tile discharge by 66%, relative to DR. The 4-year FWM nitrate concentration during Phase 2 in tile discharge was below the drinking water guideline for both DR (7.3 mg N l–1 and CDS (4.0 mg N l–1. During both phases of the experiment, the CDS treatment caused only minor increases in nitrate loss in surface runoff relative to DR. Hence CDS decreased FWM nitrate concentrations, total drainage water loss, and total nitrate loss in tile discharge relative to DR. In addition, soybean-corn rotation reduced FWM nitrate concentrations and total nitrate loss in tile discharge

  18. Fractal water quality fluctuations spanning the periodic table in an intensively farmed watershed.

    Science.gov (United States)

    Aubert, Alice H; Kirchner, James W; Gascuel-Odoux, Chantal; Faucheux, Mikael; Gruau, Gérard; Mérot, Philippe

    2014-01-21

    Recently developed measurement technologies can monitor surface water quality almost continuously, creating high-frequency multiparameter time series and raising the question of how best to extract insights from such rich data sets. Here we use spectral analysis to characterize the variability of water quality at the AgrHys observatory (Western France) over time scales ranging from 20 min to 12 years. Three years of daily sampling at the intensively farmed Kervidy-Naizin watershed reveal universal 1/f scaling for all 36 solutes, yielding spectral slopes of 1.05 ± 0.11 (mean ± standard deviation). These 36 solute concentrations show varying degrees of annual cycling, suggesting different controls on watershed export processes. Twelve years of daily samples of SO4, NO3, and dissolved organic carbon (DOC) show that 1/f scaling does not continue at frequencies below 1/year in those constituents, whereas a 12-year daily record of Cl shows a general 1/f trend down to the lowest measurable frequencies. Conversely, approximately 12 months of 20 min NO3 and DOC measurements show that at frequencies higher than 1/day, the spectra of these solutes steepen to slopes of roughly 3, and at time scales shorter than 2-3 h, the spectra flatten to slopes near zero, reflecting analytical noise. These results confirm and extend the recent discovery of universal fractal 1/f scaling in water quality at the relatively pristine Plynlimon watershed in Wales, further demonstrating the importance of advective-dispersive transport mixing in catchments. However, the steeper scaling at subdaily time scales suggests additional short-term damping of solute concentrations, potentially due to in-stream or riparian processes.

  19. BOREAS TGB-1/TGB-3 Water Table and Peat Temperature Data over the NSA

    Science.gov (United States)

    Bubier, Jill L.; Comer, Neil; Moore, Tim R.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOREAS TGB-1 and TGB-3 teams collected several data sets that contributed to understanding the measured trace gas fluxes over sites in the NSA. This data set contains continuous and manual measurements of water level and air and soil temperatures at the four subsites within the NSA Tower Fen site complex. The measurements were taken to understand the thermal and hydrological gradients associated with each plant community present in the fen. Measurements were taken from May to September 1994 and May to October 1996. The data are provided in tabular ASCII files.

  20. Numerical hydrodynamic analysis of an offshore stationary–floating oscillating water column–wave energy converter using CFD

    Directory of Open Access Journals (Sweden)

    Ahmed Elhanafi

    2017-01-01

    Full Text Available Offshore oscillating water columns (OWC represent one of the most promising forms of wave energy converters. The hydrodynamic performance of such converters heavily depends on their interactions with ocean waves; therefore, understanding these interactions is essential. In this paper, a fully nonlinear 2D computational fluid dynamics (CFD model based on RANS equations and VOF surface capturing scheme is implemented to carry out wave energy balance analyses for an offshore OWC. The numerical model is well validated against published physical measurements including; chamber differential air pressure, chamber water level oscillation and vertical velocity, overall wave energy extraction efficiency, reflected and transmitted waves, velocity and vorticity fields (PIV measurements. Following the successful validation work, an extensive campaign of numerical tests is performed to quantify the relevance of three design parameters, namely incoming wavelength, wave height and turbine damping to the device hydrodynamic performance and wave energy conversion process. All of the three investigated parameters show important effects on the wave–pneumatic energy conversion chain. In addition, the flow field around the chamber's front wall indicates areas of energy losses by stronger vortices generation than the rear wall.

  1. Experimental research on density wave oscillation of steam-water two-phase flow in parallel inclined internally ribbed pipes

    International Nuclear Information System (INIS)

    Gao Feng; Chen Tingkuan; Luo Yushan; Yin Fei; Liu Weimin

    2005-01-01

    At p=3-10 MPa, G=300-600 kg/(m 2 ·s), Δt sub =30-90 degree C, and q=0-190 kW/m 2 , the experiments on steam-water two-phase flow instabilities have been performed. The test sections are parallel inclined internally ribbed pipes with an outer diameter of φ38.1 mm, a wall thinkness of 7.5 mm, a obliquity of 19.5 and a length more than 15 m length. Based on the experimental results, the effects of pressure, mass velocity, inlet subcooling and asymmetrical heat flux on steam-water two-phase flow density wave oscillation were analyzed. The experimental results showed that the flow system were more stable as pressure increased. As an increase in mass velocity, critical heat flux increased but critical steam quality decreased. Inlet subcooling had a monotone effect on density wave oscillation, when inlet subcooling decreased, critical heat flux decreased. Under a certain working condition, critical heat flux on asymmetrically heating parallel pipes is higher than that on symmetrically heating parallel pipes, that means the system with symmetrically heating parallel pips was more stable. (authors)

  2. Performance of methods for estimation of table beet water requirement in Alagoas

    Directory of Open Access Journals (Sweden)

    Daniella P. dos Santos

    Full Text Available ABSTRACT Optimization of water use in agriculture is fundamental, particularly in regions where water scarcity is intense, requiring the adoption of technologies that promote increased irrigation efficiency. The objective of this study was to evaluate evapotranspiration models and to estimate the crop coefficients of beet grown in a drainage lysimeter in the Agreste region of Alagoas. The experiment was conducted at the Campus of the Federal University of Alagoas - UFAL, in the municipality of Arapiraca, AL, between March and April 2014. Crop evapotranspiration (ETc was estimated in drainage lysimeters and reference evapotranspiration (ETo by Penman-Monteith-FAO 56 and Hargreaves-Samani methods. The Hargreaves-Samani method presented a good performance index for ETo estimation compared with the Penman-Monteith-FAO method, indicating that it is adequate for the study area. Beet ETc showed a cumulative demand of 202.11 mm for a cumulative reference evapotranspiration of 152.00 mm. Kc values determined using the Penman-Monteith-FAO 56 and Hargreaves-Samani methods were overestimated, in comparison to the Kc values of the FAO-56 standard method. With the obtained results, it is possible to correct the equations of the methods for the region, allowing for adequate irrigation management.

  3. Long-term Water Table Monitoring of Rio Grande Riparian Ecosystems for Restoration Potential Amid Hydroclimatic Challenges

    Science.gov (United States)

    Thibault, James R.; Cleverly, James R.; Dahm, Clifford N.

    2017-12-01

    Hydrological processes drive the ecological functioning and sustainability of cottonwood-dominated riparian ecosystems in the arid southwestern USA. Snowmelt runoff elevates groundwater levels and inundates floodplains, which promotes cottonwood germination. Once established, these phreatophytes rely on accessible water tables (WTs). In New Mexico's Middle Rio Grande corridor diminished flooding and deepening WTs threaten native riparian communities. We monitored surface flows and riparian WTs for up to 14 years, which revealed that WTs and surface flows, including peak snowmelt discharge, respond to basin climate conditions and resource management. WT hydrographs influence the composition of riparian communities and can be used to assess if potential restoration sites meet native vegetation tolerances for WT depths, rates of recession, and variability throughout their life stages. WTs were highly variable in some sites, which can preclude native vegetation less adapted to deep drawdowns during extended droughts. Rates of WT recession varied between sites and should be assessed in regard to recruitment potential. Locations with relatively shallow WTs and limited variability are likely to be more viable for successful restoration. Suitable sites have diminished greatly as the once meandering Rio Grande has been constrained and depleted. Increasing demands on water and the presence of invasive vegetation better adapted to the altered hydrologic regime further impact native riparian communities. Long-term monitoring over a range of sites and hydroclimatic extremes reveals attributes that can be evaluated for restoration potential.

  4. The Contribution of Environmental Siting and Permitting Requirements to the Cost of Energy for Oscillating Water Column Wave Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    Copping, Andrea E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Geerlofs, Simon H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hanna, Luke A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-09-01

    Responsible deployment of marine and hydrokinetic (MHK) devices in estuaries, coastal areas, and major rivers requires that biological resources and ecosystems be protected through siting and permitting (consenting) processes. Scoping appropriate deployment locations, collecting pre-installation (baseline) and post-installation data all add to the cost of developing MHK projects, and hence to the cost of energy. Under the direction of the U.S. Department of Energy, Pacific Northwest National Laboratory scientists have developed logic models that describe studies and processes for environmental siting and permitting. Each study and environmental permitting process has been assigned a cost derived from existing and proposed tidal, wave, and riverine MHK projects, as well as expert opinion of marine environmental research professionals. Cost estimates have been developed at the pilot and commercial scale. The reference model described in this document is an oscillating water column device deployed in Northern California at approximately 50 meters water depth.

  5. Soil chemistry and ground-water quality of the water-table zone of the surficial aquifer, Naval Submarine Base Kings Bay, Camden County, Georgia, 1998 and 1999

    Science.gov (United States)

    Leeth, David C.

    2002-01-01

    In 1998, the U.S. Geological Survey, in cooperation with the U.S. Department of the Navy, began an investigation to determine background ground-water quality of the water-table zone of the surficial aquifer and soil chemistry at Naval Submarine Base Kings Bay, Camden County, Georgia, and to compare these data to two abandoned solid- waste disposal areas (referred to by the U.S. Navy as Sites 5 and 16). The quality of water in the water-table zone generally is within the U.S. Environmental Protection Agency (USEPA) drinking-water regulation. The pH of ground water in the study area ranged from 4.0 to 7.6 standard units, with a median value of 5.4. Water from 29 wells is above the pH range and 3 wells are within the range of the USEPA secondary drinking-water regulation (formerly known as the Secondary Maximum Contaminant Level or SMCL) of 6.5 to 8.5 standard units. Also, water from one well at Site 5 had a chloride concentration of 570 milligrams per liter (mg/L,), which is above the USEPA secondary drinking-water regulation of 250 mg/L. Sulfate concentrations in water from two wells at Site 5 are above the USEPA secondary drinking-water regulation of 250 mg/L. Of 22 soil-sampling locations for this study, 4 locations had concentrations above the detection limit for either volatile organic compounds (VOCs), base-neutral acids (BNAs), or pesticides. VOCs detected in the study area include toluene in one background sample; and acetone in one background sample and one sample from Site 16--however, detection of these two compounds may be a laboratory artifact. Pesticides detected in soil at the Submarine Base include two degradates of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT): 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (4,4'-DDD) in one background sample, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (4,4'-DDE) in one background sample and one sample from Site 16; and dibenzofuran in one sample from Site 16. BNAs were detected in one background sample and in two

  6. Polder effects on sediment-to-soil conversion: water table, residual available water capacity, and salt stress interdependence.

    Science.gov (United States)

    Radimy, Raymond Tojo; Dudoignon, Patrick; Hillaireau, Jean Michel; Deboute, Elise

    2013-01-01

    The French Atlantic marshlands, reclaimed since the Middle Age, have been successively used for extensive grazing and more recently for cereal cultivation from 1970. The soils have acquired specific properties which have been induced by the successive reclaiming and drainage works and by the response of the clay dominant primary sediments, that is, structure, moisture, and salinity profiles. Based on the whole survey of the Marais Poitevin and Marais de Rochefort and in order to explain the mechanisms of marsh soil behavior, the work focuses on two typical spots: an undrained grassland since at least 1964 and a drained cereal cultivated field. The structure-hydromechanical profiles relationships have been established thanks to the clay matrix shrinkage curve. They are confronted to the hydraulic functioning including the fresh-to-salt water transfers and to the recording of tensiometer profiles. The CE1/5 profiles supply the water geochemical and geophysical data by their better accuracy. Associated to the available water capacity calculation they allow the representation of the parallel evolution of the residual available water capacity profiles and salinity profiles according to the plant growing and rooting from the mesophile systems of grassland to the hygrophile systems of drained fields.

  7. Polder Effects on Sediment-to-Soil Conversion: Water Table, Residual Available Water Capacity, and Salt Stress Interdependence

    Directory of Open Access Journals (Sweden)

    Raymond Tojo Radimy

    2013-01-01

    Full Text Available The French Atlantic marshlands, reclaimed since the Middle Age, have been successively used for extensive grazing and more recently for cereal cultivation from 1970. The soils have acquired specific properties which have been induced by the successive reclaiming and drainage works and by the response of the clay dominant primary sediments, that is, structure, moisture, and salinity profiles. Based on the whole survey of the Marais Poitevin and Marais de Rochefort and in order to explain the mechanisms of marsh soil behavior, the work focuses on two typical spots: an undrained grassland since at least 1964 and a drained cereal cultivated field. The structure-hydromechanical profiles relationships have been established thanks to the clay matrix shrinkage curve. They are confronted to the hydraulic functioning including the fresh-to-salt water transfers and to the recording of tensiometer profiles. The CE1/5 profiles supply the water geochemical and geophysical data by their better accuracy. Associated to the available water capacity calculation they allow the representation of the parallel evolution of the residual available water capacity profiles and salinity profiles according to the plant growing and rooting from the mesophile systems of grassland to the hygrophile systems of drained fields.

  8. Oscillator-strength distributions for oxygen, carbon dioxide, water, methyl chloride, and carbon tetrachloride

    International Nuclear Information System (INIS)

    Person, J.C.; Nicole, P.P.

    1979-01-01

    New measurements of photoabsorption give oscillator-strength values for the following gases and energy regions: O 2 , 7.34 to 11.79 eV; CO 2 , 7.34 to 11.77 eV; H 2 O, 6.62 to 11.80 eV; CH 3 CL, 6.14 to 11.25 eV; and CCl 4 , 6.14 to 11.49 eV. Comparisons are made with some values from the literature

  9. Changes in soluble metal concentrations induced by variable water table levels as response to liming and Phragmites australis growth in metal-polluted wetland soils: Management effectiveness

    NARCIS (Netherlands)

    Gonzalez Alcaraz, M.N.; van Gestel, C.A.M.

    2016-01-01

    This study aimed to assess the effectiveness of liming and Phragmites australis growth for the management of metal-polluted wetland soils under fluctuating water table levels. Soil columns (20 cm in diameter and 60 cm high) were constructed with two soil types (pH ~ 6.4 and pH ~ 3.1) and four

  10. Mobility and transport of mercury and methylmercury in peat as a function of changes in water table regime and plant functional groups

    Science.gov (United States)

    Kristine M. Haynes; Evan S. Kane; Lynette Potvin; Erik A. Lilleskov; Randy Kolka; Carl P. J. Mitchell

    2017-01-01

    Climate change is likely to significantly affect the hydrology, ecology, and ecosystem function of peatlands, with potentially important but unclear impacts on mercury mobility within and transport from peatlands. Using a full-factorial mesocosm approach, we investigated the potential impacts on mercury mobility of water table regime changes (high and low) and...

  11. Water table and species identity outweigh carbon and nitrogen availability in a softwater plant community

    Science.gov (United States)

    Vanderhaeghe, Floris; Smolders, Alfons J. P.; Roelofs, Jan G. M.; Hoffmann, Maurice

    2013-02-01

    Performance of aquatic macrophytes is driven by many environmental factors, and a major challenge is to understand how aquatic macrophyte communities are structured in various environments. In softwater lakes in Western Europe, hydrological state (submersed/emersed), carbon dioxide and ammonium levels and species interactions are considered as driving forces in structuring amphibious plant communities. In this study we aimed at evaluating the relative importance of these factors for four species in a competitive neighbourhood. Softwater lake habitat was simulated during one growing season in laboratory conditions, mimicking water level fluctuation, photoperiod and temperature. Artificial communities consisted of small populations of four softwater macrophyte species: Luronium natans, Baldellia ranunculoides ssp. repens, Eleocharis multicaulis and Hydrocotyle vulgaris. These communities were subjected to two levels of carbon dioxide and ammonium. Additionally, monocultures of Baldellia and Eleocharis were grown at a higher nutrient level combination in order to measure their competitive response in a community. Time (hydrological state) and species identity turned out to be the only consistently significant factors determining community composition. Plant performance was clearly species-dependent, while carbon dioxide and ammonium did not have major effects. The competitive response was significant in both Eleocharis and Baldellia. Competition intensity was highest in the emersed state. Carbon dioxide had a supplementary effect on the within-species performance in Luronium, Baldellia and Eleocharis, with high carbon dioxide level mainly resulting in more flowers and more stolons. Community outcomes and competitive responses in aquatic macrophytes appear difficult to predict, because of mixed life strategies and morphological and functional plasticity. We conclude that hydrological state was the only important environmental factor. The identity of the species that

  12. Hydrogeologic characteristics and geospatial analysis of water-table changes in the alluvium of the lower Arkansas River Valley, southeastern Colorado, 2002, 2008, and 2015

    Science.gov (United States)

    Holmberg, Michael J.

    2017-05-15

    The U.S. Geological Survey in cooperation with the Lower Arkansas Valley Water Conservancy District measures groundwater levels periodically in about 100 wells completed in the alluvial material of the Arkansas River Valley in Pueblo, Crowley, Otero, Bent, and Prowers Counties in southeastern Colorado, of which 95 are used for the analysis in this report. The purpose of this report is to provide information to water-resource administrators, managers, planners, and users about groundwater characteristics in the alluvium of the lower Arkansas Valley extending roughly 150 miles between Pueblo Reservoir and the Colorado-Kansas State line. This report includes three map sheets showing (1) bedrock altitude at the base of the alluvium of the lower Arkansas Valley; (2) estimated spring-to-spring and fall-to-fall changes in water-table altitude between 2002, 2008, and 2015; and (3) estimated saturated thickness in the alluvium during spring and fall of 2002, 2008, and 2015, and thickness of the alluvium in the lower Arkansas Valley. Water-level changes were analyzed by geospatial interpolation methods.Available data included all water-level measurements made between January 1, 2001, and December 31, 2015; however, only data from fall and spring of 2002, 2008, and 2015 are mapped in this report. To account for the effect of John Martin Reservoir in Bent County, Colorado, lake levels at the reservoir were assigned to points along the approximate shoreline and were included in the water-level dataset. After combining the water-level measurements and lake levels, inverse distance weighting was used to interpolate between points and calculate the altitude of the water table for fall and spring of each year for comparisons. Saturated thickness was calculated by subtracting the bedrock surface from the water-table surface. Thickness of the alluvium was calculated by subtracting the bedrock surface from land surface using a digital elevation model.In order to analyze the response

  13. Optimization and Annual Average Power Predictions of a Backward Bent Duct Buoy Oscillating Water Column Device Using the Wells Turbine.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Christopher S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Willits, Steven M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fontaine, Arnold A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    This Technical Report presents work completed by The Applied Research Laboratory at The Pennsylvania State University, in conjunction with Sandia National Labs, on the optimization of the power conversion chain (PCC) design to maximize the Average Annual Electric Power (AAEP) output of an Oscillating Water Column (OWC) device. The design consists of two independent stages. First, the design of a floating OWC, a Backward Bent Duct Buoy (BBDB), and second the design of the PCC. The pneumatic power output of the BBDB in random waves is optimized through the use of a hydrodynamically coupled, linear, frequency-domain, performance model that links the oscillating structure to internal air-pressure fluctuations. The PCC optimization is centered on the selection and sizing of a Wells Turbine and electric power generation equipment. The optimization of the PCC involves the following variables: the type of Wells Turbine (fixed or variable pitched, with and without guide vanes), the radius of the turbine, the optimal vent pressure, the sizing of the power electronics, and number of turbines. Also included in this Technical Report are further details on how rotor thrust and torque are estimated, along with further details on the type of variable frequency drive selected.

  14. Evaluation of a mechanistic algorithm to calculate the influence of a shallow water table on hydrology sediment and pesticide transport through vegetative filter strips

    Science.gov (United States)

    Lauvernet, C.; Munoz-Carpena, R.; Carluer, N.

    2012-04-01

    Natural or introduced areas of vegetation, also known as vegetative filter strips (VFS), are a common environmental control practice to protect surface water bodies from human influence. In Europe, VFS are placed along the water network to protect from agrochemical drift during applications, in addition to runoff control. Their bottomland placement next to the streams often implies the presence of a seasonal shallow water table which can have a profound impact on the efficiency of the buffer zone (Lacas et al. 2005). A physically-based algorithm describing ponded infiltration into soils bounded by a water table, proposed by Salvucci and Enthekabi (1995), was further developed to simulate VFS dynamics by making it explicit in time, account for unsteady rainfall conditions, and by coupling to a numerical overland flow and transport model (VFSMOD) (Munoz-Carpena et al., submitted). In this study, we evaluate the importance of the presence of a shallow water table on filter efficiency (reductions in runoff, sediment and pesticide mass), in the context of all other input factors used to describe the system. Global sensitivity analysis (GSA) was used to rank the important input factors and the presence of interactions, as well as the contribution of the important factors to the output variance. GSA of VSFMOD modified for shallow water table was implemented on 2 sites selected in France because they represent different agro-pedo-climatic conditions for which we can compare the role of the factors influencing the performance of grassed buffer strips for surface runoff, sediment and pesticide removal. The first site at Morcille watershed in the Beaujolais wineyard (Rhône-Alpes) contains a very permeable sandy-clay with water table depth varying with the season (very deep in summer and shallow in winter), with a high slope (20 to 30%), and subject to strong seasonal storms (semi-continental, Mediterranean climate). The second site at La Jailliere (Loire-Atlantique, ARVALIS

  15. The reconstruction of late Holocene depth-to-water-table based on testate amoebae in an eastern Australian mire

    Science.gov (United States)

    Zheng, X.; Money, S.; Hope, G.

    2017-12-01

    There are relatively few quantitative palaeo-hydrological records available in eastern Australia, and those that are available, for example from dendroclimatology and the reconstruction of lake level, are often relatively short or have a relatively coarse temporal resolution (e.g. Wilkins et al. 2013; Palmer et al. 2015). Testate amoebae, a widely used hydrological proxy in the Northern Hemisphere, were used here to reconstruct depth to water table (DWT) at Snowy Flat, which is a Sphagnum-Richea-Empodismahigh altitude (1618 m asl) shrub bog in the Australian Capital Territory, Australia. Testate amoebae were quantified in a Snowy Flat core representing 4,200 cal Y BP and the community composition was used to reconstruct DWT based on our recently established transfer functions. Results from three different types of transfer functions (Fig. 1) consistently show there was a decreasing DWT (wetter) period centred on about 3350 cal Y BP, a trend towards increased dryness from about 3300 to 2200 cal Y BP and a distinctly drier period 850 to 700 cal Y BP which was immediately followed by a wetter period from 700 to 500 cal Y BP. We discuss these episodes and trends in relation to the drivers of climatic variability in this region and in particular, by comparing our results with other south-eastern Australia records, comment on the history of the southern annular mode.

  16. Analysis on oscillating actuator frequency influence of the fluid flow characterization for 2D contractile water jet thruster

    Science.gov (United States)

    Shaari, M. F.; Abu Bakar, H.; Nordin, N.; Saw, S. K.; Samad, Z.

    2013-12-01

    Contractile body is an alternative mechanism instead of rotating blade propeller to generate water jet for locomotion. The oscillating motion of the actuator at different frequencies varies the pressure and volume of the pressure chamber in time to draw in and jet out the water at a certain mass flow rate. The aim of this research was to analyze the influence of the actuating frequency of the fluid flow in the pressure chamber of the thruster during this inflation-deflation process. A 70mm × 70mm × 18mm (L × W × T) 2D water jet thruster was fabricated for this purpose. The contractile function was driven using two lateral pneumatic actuators where the fluid flow analysis was focused on the X-Y plane vector. Observation was carried out using a video camera and Matlab image measurement technique to determine the volume of the flowing mass. The result demonstrated that the greater actuating frequency decreases the fluid flow rate and the Reynolds number. This observation shows that the higher frequency would give a higher mass flow rate during water jet generation.

  17. Use of geospatial technology for delineating groundwater potential zones with an emphasis on water-table analysis in Dwarka River basin, Birbhum, India

    Science.gov (United States)

    Thapa, Raju; Gupta, Srimanta; Gupta, Arindam; Reddy, D. V.; Kaur, Harjeet

    2018-05-01

    Dwarka River basin in Birbhum, West Bengal (India), is an agriculture-dominated area where groundwater plays a crucial role. The basin experiences seasonal water stress conditions with a scarcity of surface water. In the presented study, delineation of groundwater potential zones (GWPZs) is carried out using a geospatial multi-influencing factor technique. Geology, geomorphology, soil type, land use/land cover, rainfall, lineament and fault density, drainage density, slope, and elevation of the study area were considered for the delineation of GWPZs in the study area. About 9.3, 71.9 and 18.8% of the study area falls within good, moderate and poor groundwater potential zones, respectively. The potential groundwater yield data corroborate the outcome of the model, with maximum yield in the older floodplain and minimum yield in the hard-rock terrains in the western and south-western regions. Validation of the GWPZs using the yield of 148 wells shows very high accuracy of the model prediction, i.e., 89.1% on superimposition and 85.1 and 81.3% on success and prediction rates, respectively. Measurement of the seasonal water-table fluctuation with a multiplicative model of time series for predicting the short-term trend of the water table, followed by chi-square analysis between the predicted and observed water-table depth, indicates a trend of falling groundwater levels, with a 5% level of significance and a p-value of 0.233. The rainfall pattern for the last 3 years of the study shows a moderately positive correlation ( R 2 = 0.308) with the average water-table depth in the study area.

  18. The Effect of Water Table Fluctuation and its Salinity on Fe Crystal and Noncrystal in some Khuzestan Soils

    Directory of Open Access Journals (Sweden)

    mostafa Pajohannia

    2017-01-01

    Full Text Available Introduction: Iron is found in different forms in the soil. In the primary minerals, iron is found as Fe3+ or Fe2+ which converted to Fe2+ and released in unsuitable reduction conditions. Minerals such as sulfide or chlorine and bicarbonate can affect and change the different forms soil Fe. FeAs these elements are abundance in groundwater or soil, they are capable to react chemically with Fe and change different Fe forms and also may deposit or even leach them by increasing its solubility in the soil. Water table fluctuation is a regular phenomenon in Khuzestan that Fe forms change under these situations. The study of Fe oxide forms and its changes can be applied for evaluation of soil development. Therefore, the aim of this study is the water table fluctuation and its quality effects, and some physio-chemical properties on Fe oxides forms in non-saline and saline soils in Khuzestan. Materials and Methods: Soil samples were collected from two regions: saline (Abdolkhan and non-saline (South Susa regions. soil samples were collected from all horizons of 12 soil field studied profiles . The samples were analyzed for soil texture, pH, EC (soil: water ratio 1:5, organic carbon and aggregate stability (Kemper and Rosenau method. Fe forms also were extracted by two methods in all samples: di-tyonite sodium and ammonium oxalate extraction. Fe oxalate extracted was related to Feo (non crystal Fe and Fed-Feo was related to Fec (crystalline Fe. The Fe content were determined by atomic absorbtion spectrophotometer (AAS. Data were analysis in SAS and Excel software and results were presented. Results and Discussion: The results showed that texture were loamy sand to silty clay loam, OM was very poor (0.1-0.7%. The soil salinity was also 2.8-16.8 dS/m. Calcium carbonate equivalent was 38-40%. All pedons were classified in Entisols and Inceptisols according to Keys to soil taxonomy (2010. The results showed that the proportion of Fe with oxalate to di

  19. Comparison of groundwater transit velocity estimates from flux theory and water table recession based approaches for solute transport.

    Science.gov (United States)

    Rasiah, Velu; Armour, John David

    2013-02-15

    Reliable information in transit time (TT) derived from transit velocity (TV) for rain or irrigation water to mix with groundwater (GW) and the subsequent discharge to surface water bodies (SWB) is essential to address the issues associated with the transport of nutrients, particularly nitrate, from GW to SWB. The objectives of this study are to (i) compare the TV estimates obtained using flux theory-based (FT) approach with the water table rise/recession (WT) rate approach and (ii) explore the impact of the differences on solute transport from GW to SWB. The results from a study conducted during two rainy seasons in the northeast humid tropics of Queensland, Australia, showed the TV varied in space and over time and the variations depended on the estimation procedures. The lateral TV computed using the WT approach ranged from 1.00 × 10(-3) to 2.82 × 10(-1) m/d with a mean of 6.18 × 10(-2) m/d compared with 2.90 × 10(-4) to 5.15 × 10(-2) m/d for FT with a mean of 2.63 × 10(-2) m/d. The vertical TV ranged from 2.00 × 10(-3) to 6.02 × 10(-1) m/d with a mean of 1.28 × 10(-1) m/d for the WT compared with 6.76 × 10(-3)-1.78 m/d for the FT with a mean of 2.73 × 10(-1) m/d. These differences are attributed to the role played by different flow pathways. The bypass flow pathway played a role only in WT but not in FT. Approximately 86-95% of the variability in lateral solute transport was accounted for by the lateral TV and the total recession between two consecutive major rainfall events. A comparison of TT from FT and WT approaches indicated the laterally transported nitrate from the GW to the nearby creek was relatively 'new', implying the opportunity for accumulation and to undergo biochemical reactions in GW was low. The results indicated the WT approach produced more reliable TT estimates than FT in the presence of bypass flow pathways. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Does the oscillation of the water volume of the reservoir influence in the same way in fish diet?

    Directory of Open Access Journals (Sweden)

    Jean Carlos Dantas de Oliveira

    2018-04-01

    Full Text Available Abstract Aim: To evaluate the fish feeding and to establish the preferential and secondary items of their diets, to determine the trophic guilds and the possible trophic structure variations in function of the water volume in Umari reservoir, Rio Grande do Norte, Brazilian semiarid. Methods The fish were captured quarterly between February and November of 2013, with gill nets with different meshes, being the apparatuses exposed at 5:00 p.m., with removal at 5:00 a.m. The food items were identified using stereoscopic and optical microscopes and evaluated through the Feeding Index (IAi, being the results of this procedure used in food similarity analysis. The volume of the items was orderly in NMDS and the time differences were tested in PERMANOVA. Results A total of 740 individuals belonging to 14 species were sampled, being analyzed a total of 258 stomachs and 8 intestines of 11 species. From the IAi values used in the trophic similarity analysis, the species were classified into five trophic guilds: detritivorous, insectivorous, malacophagous, carcinophagous and piscivorous. Conclusion The oscillation in the water volume of the reservoir did not influence the diet of the guild detritivorous, which shows that the variations in the volume of water of the reservoir do not influence in the same way the diet of the local ichthyofauna.

  1. Ground-Penetrating-Radar Profiles of Interior Alaska Highways: Interpretation of Stratified Fill, Frost Depths, Water Table, and Thaw Settlement over Ice-Rich Permafrost

    Science.gov (United States)

    2016-08-01

    along either massive ice surfaces or within sections of segregated ice. The uninsulated ice surface at Tok in Figure 17B is irregular. All of the...ER D C/ CR RE L TR -1 6- 14 ERDC’s Center-Directed Research Program Ground -Penetrating-Radar Profiles of Interior Alaska Highways...August 2016 Ground -Penetrating-Radar Profiles of Interior Alaska Highways Interpretation of Stratified Fill, Frost Depths, Water Table, and Thaw

  2. Chaotic behavior of water column oscillator simulating pressure balanced injection system in passive safety reactor

    International Nuclear Information System (INIS)

    Morimoto, Y.; Madarame, H.; Okamoto, K.

    2001-01-01

    Japan Atomic Energy Research Institute (JAERI) proposed a passive safety reactor called the System-integrated Pressurized Water Reactor (SPWR). In a loss of coolant accident, the Pressurizing Line (PL) and the Injection Line (IL) are passively opened. Vapor generated by residual heat pushes down the water level in the Reactor Vessel (RV). When the level is lower than the inlet of the PL, the vapor is ejected into the Containment Vessel (CV) through the PL. Then boronized water in the CV is injected into the RV through the IL by the static head. In an experiment using a simple apparatus, gas ejection and water injection were found to occur alternately under certain conditions. The gas ejection interval was observed to fluctuate considerably. Though stochastic noise affected the interval, the experimental results suggested that the large fluctuation was produced by an inherent character in the system. A set of piecewise linear differential equations was derived to describe the experimental result. The large fluctuation was reproduced in the analytical solution. Thus it was shown to occur even in a deterministic system without any source of stochastic noise. Though the derived equations simulated the experiment well, they had ten independent parameters governing the behavior of the solution. There appeared chaotic features and bifurcation, but the analytical model was too complicated to examine the features and mechanism of bifurcation. In this study, a new simple model is proposed which consists of a set of piecewise linear ordinary differential equations with only four independent parameters. (authors)

  3. 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

  4. Sub-tidal water-level oscillations in the Mandovi estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; Vijith, V.

    of rainfall associated with the ISM and its interannual and intraseasonal variability. With most of the rainfall occurring during the wet ISM, most of the runoff into the estuaries is also during the same season. There is virtually no runoff... water level computed using the pressure sensor versus that using the tide pole shows that the high-frequency scatter is larger for the tide-pole measurements. However, the low-pass filtered variability is virtually identical in the tide...

  5. Environmental fate of Ra in cation-exchange regeneration brine waste disposed to septic tanks, New Jersey Coastal Plain, USA: migration to the water table.

    Science.gov (United States)

    Szabo, Zoltan; Jacobsen, Eric; Kraemer, Thomas F; Parsa, Bahman

    2010-01-01

    Fate of radium (Ra) in liquid regeneration brine wastes from water softeners disposed to septic tanks in the New Jersey Coastal Plain was studied. Before treatment, combined Ra ((226)Ra plus (228)Ra) concentrations (maximum, 1.54 Bq L(-1)) exceeded the 0.185 Bq L(-1) Maximum Contaminant Level in 4 of 10 studied domestic-well waters (median pH, 4.90). At the water table downgradient from leachfields, combined Ra concentrations were low (commonly 5.3, indicating sequestration; when pH was septic-tank effluents (maximum, 0.243 Bq L(-1))), indicating Ra mobilization from leachfield sediments. Confidence in quantification of Ra mass balance was reduced by study design limitations, including synoptic sampling of effluents and ground waters, and large uncertainties associated with analytical methods. The trend of Ra mobilization in acidic environments does match observations from regional water-quality assessments.

  6. Molecular mechanisms of water table lowering and nitrogen deposition in affecting greenhouse gas emissions from a Tibetan alpine wetland.

    Science.gov (United States)

    Wang, Hao; Yu, Lingfei; Zhang, Zhenhua; Liu, Wei; Chen, Litong; Cao, Guangmin; Yue, Haowei; Zhou, Jizhong; Yang, Yunfeng; Tang, Yanhong; He, Jin-Sheng

    2017-02-01

    Rapid climate change and intensified human activities have resulted in water table lowering (WTL) and enhanced nitrogen (N) deposition in Tibetan alpine wetlands. These changes may alter the magnitude and direction of greenhouse gas (GHG) emissions, affecting the climate impact of these fragile ecosystems. We conducted a mesocosm experiment combined with a metagenomics approach (GeoChip 5.0) to elucidate the effects of WTL (-20 cm relative to control) and N deposition (30 kg N ha -1  yr -1 ) on carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) fluxes as well as the underlying mechanisms. Our results showed that WTL reduced CH 4 emissions by 57.4% averaged over three growing seasons compared with no-WTL plots, but had no significant effect on net CO 2 uptake or N 2 O flux. N deposition increased net CO 2 uptake by 25.2% in comparison with no-N deposition plots and turned the mesocosms from N 2 O sinks to N 2 O sources, but had little influence on CH 4 emissions. The interactions between WTL and N deposition were not detected in all GHG emissions. As a result, WTL and N deposition both reduced the global warming potential (GWP) of growing season GHG budgets on a 100-year time horizon, but via different mechanisms. WTL reduced GWP from 337.3 to -480.1 g CO 2 -eq m -2 mostly because of decreased CH 4 emissions, while N deposition reduced GWP from 21.0 to -163.8 g CO 2 -eq m -2 , mainly owing to increased net CO 2 uptake. GeoChip analysis revealed that decreased CH 4 production potential, rather than increased CH 4 oxidation potential, may lead to the reduction in net CH 4 emissions, and decreased nitrification potential and increased denitrification potential affected N 2 O fluxes under WTL conditions. Our study highlights the importance of microbial mechanisms in regulating ecosystem-scale GHG responses to environmental changes. © 2016 John Wiley & Sons Ltd.

  7. Hybrid Wing Body Model Identification Using Forced-Oscillation Water Tunnel Data

    Science.gov (United States)

    Murphy, Patrick C.; Vicroy, Dan D.; Kramer, Brian; Kerho, Michael

    2014-01-01

    Static and dynamic testing of the NASA 0.7 percent scale Hybrid Wing Body (HWB) configuration was conducted in the Rolling Hills Research Corporation water tunnel to investigate aerodynamic behavior over a large range of angle-of-attack and to develop models that can predict aircraft response in nonlinear unsteady flight regimes. This paper reports primarily on the longitudinal axis results. Flow visualization tests were also performed. These tests provide additional static data and new dynamic data that complement tests conducted at NASA Langley 14- by 22-Foot Subsonic Tunnel. HWB was developed to support the NASA Environmentally Responsible Aviation Project goals of lower noise, emissions, and fuel burn. This study also supports the NASA Aviation Safety Program efforts to model and control advanced transport configurations in loss-of-control conditions.

  8. Prediction of regular wave loads on a fixed offshore oscillating water column-wave energy converter using CFD

    Directory of Open Access Journals (Sweden)

    Ahmed Elhanafi

    2016-12-01

    Full Text Available In this paper, hydrodynamic wave loads on an offshore stationary–floating oscillating water column (OWC are investigated via a 2D and 3D computational fluid dynamics (CFD modeling based on the RANS equations and the VOF surface capturing scheme. The CFD model is validated against previous experiments for nonlinear regular wave interactions with a surface-piercing stationary barge. Following the validation stage, the numerical model is modified to consider the pneumatic damping effect, and an extensive campaign of numerical tests is carried out to study the wave–OWC interactions for different wave periods, wave heights and pneumatic damping factors. It is found that the horizontal wave force is usually larger than the vertical one. Also, there a direct relationship between the pneumatic and hydrodynamic vertical forces with a maximum vertical force almost at the device natural frequency, whereas the pneumatic damping has a little effect on the horizontal force. Additionally, simulating the turbine damping with an orifice plate induces higher vertical loads than utilizing a slot opening. Furthermore, 3D modeling significantly escalates and declines the predicted hydrodynamic vertical and horizontal wave loads, respectively.

  9. Scanning table

    CERN Multimedia

    1960-01-01

    Before the invention of wire chambers, particles tracks were analysed on scanning tables like this one. Today, the process is electronic and much faster. Bubble chamber film - currently available - (links can be found below) was used for this analysis of the particle tracks.

  10. Long-term rise of the Water Table in the Northeast US: Climate Variability, Land-Use Change, or Angry Beavers?

    Science.gov (United States)

    Boutt, D. F.

    2011-12-01

    The scientific evidence that humans are directly influencing the Earth's natural climate is increasingly compelling. Numerous studies suggest that climate change will lead to changes in the seasonality of surface water availability thereby increasing the need for groundwater development to offset those shortages. Research suggests that the Northeast region of the U.S. is experiencing significant changes to its' natural climate and hydrologic systems. Previous analysis of a long-term regional compilation of the water table response to the last 60 years of climate variability in New England documented a wide range of variability. The investigation evaluated the physical mechanisms, natural variability and response of aquifers in New England using 100 long term groundwater monitoring stations with 20 or more years of data coupled with 67 stream gages, 75 precipitation stations, and 43 temperature stations. Groundwater trends were calculated as normalized anomalies and analyzed with respect to regional compiled precipitation, temperature, and streamflow anomalies to understand the sensitivity of the aquifer systems to change. Interestingly, a trend and regression analysis demonstrate that water level fluctuations are producing statistically significant results with increasing water levels over at least the past thirty years at most (80 out of 100) well sites. In this contribution we investigate the causal mechanisms behind the observed ground water level trends using site-by-site land-use change assessments, cluster analysis, and spatial analysis of beaver populations (a possible proxy for beaver activity). Regionally, average annual precipitation has been slightly increasing since 1900, with 95% of the stations having statistically significant positive trends. Despite this, no correlation is observed between the magnitude of the annual precipitation trends and the magnitude of the groundwater level changes. Land-use change throughout the region has primarily taken

  11. Density-wave oscillations

    International Nuclear Information System (INIS)

    Belblidia, L.A.; Bratianu, C.

    1979-01-01

    Boiling flow in a steam generator, a water-cooled reactor, and other multiphase processes can be subject to instabilities. It appears that the most predominant instabilities are the so-called density-wave oscillations. They can cause difficulties for three main reasons; they may induce burnout; they may cause mechanical vibrations of components; and they create system control problems. A comprehensive review is presented of experimental and theoretical studies concerning density-wave oscillations. (author)

  12. Stochastic simulation of time-series models combined with geostatistics to predict water-table scenarios in a Guarani Aquifer System outcrop area, Brazil

    Science.gov (United States)

    Manzione, Rodrigo L.; Wendland, Edson; Tanikawa, Diego H.

    2012-11-01

    Stochastic methods based on time-series modeling combined with geostatistics can be useful tools to describe the variability of water-table levels in time and space and to account for uncertainty. Monitoring water-level networks can give information about the dynamic of the aquifer domain in both dimensions. Time-series modeling is an elegant way to treat monitoring data without the complexity of physical mechanistic models. Time-series model predictions can be interpolated spatially, with the spatial differences in water-table dynamics determined by the spatial variation in the system properties and the temporal variation driven by the dynamics of the inputs into the system. An integration of stochastic methods is presented, based on time-series modeling and geostatistics as a framework to predict water levels for decision making in groundwater management and land-use planning. The methodology is applied in a case study in a Guarani Aquifer System (GAS) outcrop area located in the southeastern part of Brazil. Communication of results in a clear and understandable form, via simulated scenarios, is discussed as an alternative, when translating scientific knowledge into applications of stochastic hydrogeology in large aquifers with limited monitoring network coverage like the GAS.

  13. Effects of leaf area index on the coupling between water table, land surface energy fluxes, and planetary boundary layer at the regional scale

    Science.gov (United States)

    Lu, Y.; Rihani, J.; Langensiepen, M.; Simmer, C.

    2013-12-01

    Vegetation plays an important role in the exchange of moisture and energy at the land surface. Previous studies indicate that vegetation increases the complexity of the feedbacks between the atmosphere and subsurface through processes such as interception, root water uptake, leaf surface evaporation, and transpiration. Vegetation cover can affect not only the interaction between water table depth and energy fluxes, but also the development of the planetary boundary layer. Leaf Area Index (LAI) is shown to be a major factor influencing these interactions. In this work, we investigate the sensitivity of water table, surface energy fluxes, and atmospheric boundary layer interactions to LAI as a model input. We particularly focus on the role LAI plays on the location and extent of transition zones of strongest coupling and how this role changes over seasonal timescales for a real catchment. The Terrestrial System Modelling Platform (TerrSysMP), developed within the Transregional Collaborative Research Centre 32 (TR32), is used in this study. TerrSysMP consists of the variably saturated groundwater model ParFlow, the land surface model Community Land Model (CLM), and the regional climate and weather forecast model COSMO (COnsortium for Small-scale Modeling). The sensitivity analysis is performed over a range of LAI values for different vegetation types as extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS) dataset for the Rur catchment in Germany. In the first part of this work, effects of vegetation structure on land surface energy fluxes and their connection to water table dynamics are studied using the stand-alone CLM and the coupled subsurface-surface components of TerrSysMP (ParFlow-CLM), respectively. The interconnection between LAI and transition zones of strongest coupling are investigated and analyzed through a subsequent set of subsurface-surface-atmosphere coupled simulations implementing the full TerrSysMP model system.

  14. Utilizing TRMM to Analyze Sea Breeze Thunderstorm Patterns During El Nino Southern Oscillations and Their Effects upon Available Fresh Water for South Florida Agricultural Planning and Management

    Science.gov (United States)

    Cooley, Clayton; Billiot, Amanda; Lee, Lucas; McKee, Jake

    2010-01-01

    Water is in high demand for farmers regardless of where you go. Unfortunately, farmers in southern Florida have fewer options for water supplies than public users and are often limited to using available supplies from surface and ground water sources which depend in part upon variable weather patterns. There is an interest by the agricultural community about the effect weather has on usable surface water, however, research into viable weather patterns during La Nina and El Nino has yet to be researched. Using rainfall accumulation data from NASA Tropical Rainfall Measurement Mission (TRMM) satellite, this project s purpose was to assess the influence of El Nino and La Nina Oscillations on sea breeze thunderstorm patterns, as well as general rainfall patterns during the summer season in South Florida. Through this research we were able to illustrate the spatial and temporal variations in rainfall accumulation for each oscillation in relation to major agricultural areas. The study period for this project is from 1998, when TRMM was first launched, to 2009. Since sea breezes in Florida typically occur in the months of May through October, these months were chosen to be the months of the study. During this time, there were five periods of El Nino and two periods of La Nina, with a neutral period separating each oscillation. In order to eliminate rainfall from systems other than sea breeze thunderstorms, only days that were conducive to the development of a sea breeze front were selected.

  15. A Country-Specific Water Consumption Inventory Considering International Trade in Asian Countries Using a Multi-Regional Input-Output Table

    Directory of Open Access Journals (Sweden)

    Yuya Ono

    2017-08-01

    Full Text Available Interest in the impacts of water use in the life cycle of products and services are increasing among various stakeholders. The water footprint is a tool to identify critical and effective points for reducing the impact of water use through the entire life cycle of products, services, and organizations. The purpose of this study was to develop a water consumption inventory database that focused on identifying of Asian water consumption using an input-output (IO framework. An Asia International Input-Output table (AIIO was applied in this study. The amount of water consumption required for agricultural products was estimated by modeling; for other sectors it was estimated from statistical reports. The intensities of direct water consumption in each sector were calculated by dividing the amount of water consumption by the domestic production. Based on the IO analysis using Leontief’s inverse matrix, the intensities of water consumption from cradle to gate were estimated for all goods and services. There was high intensity of water consumption in the primary industry sectors, together with a high dependency on rainwater as an input water source. The water consumption intensities generally showed a larger reduction in secondary sectors, in comparison with the tertiary sectors, due to the use of recycled water. There were differences between this study and previous studies due to the use of site-specific production data and the temporal resolution of crop production. By considering site-specific conditions, it is expected that the dataset developed here can be used for estimating the water footprint of products, services, and organizations in nine countries (Japan, South Korea, China, Taiwan, Thailand, the Philippines, Malaysia, Singapore, Indonesia, and USA.

  16. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

    Directory of Open Access Journals (Sweden)

    P. Straková

    2011-09-01

    Full Text Available Peatlands are carbon (C storage ecosystems sustained by a high water table (WT. High WT creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WT drawdown caused by climate and/or land-use change. Aerobic decomposers are directly affected by WT drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WT drawdown on aerobic decomposer activity in plant litter at two stages of decomposition (incubated in the field for 1 or 2 years. We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen (N, phosphorus (P and sulphur. Our study sites represented a three-stage chronosequence from pristine to short-term (years and long-term (decades WT drawdown conditions under two nutrient regimes (bog and fen. The litter types included reflected the prevalent vegetation: Sphagnum mosses, graminoids, shrubs and trees.

    Litter type was the main factor shaping microbial activity patterns and explained about 30 % of the variation in enzyme activities and activity allocation. Overall, enzyme activities were higher in vascular plant litters compared to Sphagnum litters, and the allocation of enzyme activities towards C or nutrient acquisition was related to the initial litter quality (chemical composition. Direct effects of WT regime, site nutrient regime and litter decomposition stage (length of incubation period summed to only about 40 % of the litter type effect. WT regime alone explained about 5 % of the variation in enzyme activities and activity allocation. Generally, enzyme activity increased following the long-term WT drawdown and the activity allocation turned from P

  17. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

    Science.gov (United States)

    Straková, P.; Niemi, R. M.; Freeman, C.; Peltoniemi, K.; Toberman, H.; Heiskanen, I.; Fritze, H.; Laiho, R.

    2011-09-01

    Peatlands are carbon (C) storage ecosystems sustained by a high water table (WT). High WT creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WT drawdown caused by climate and/or land-use change. Aerobic decomposers are directly affected by WT drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WT drawdown on aerobic decomposer activity in plant litter at two stages of decomposition (incubated in the field for 1 or 2 years). We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen (N), phosphorus (P) and sulphur. Our study sites represented a three-stage chronosequence from pristine to short-term (years) and long-term (decades) WT drawdown conditions under two nutrient regimes (bog and fen). The litter types included reflected the prevalent vegetation: Sphagnum mosses, graminoids, shrubs and trees. Litter type was the main factor shaping microbial activity patterns and explained about 30 % of the variation in enzyme activities and activity allocation. Overall, enzyme activities were higher in vascular plant litters compared to Sphagnum litters, and the allocation of enzyme activities towards C or nutrient acquisition was related to the initial litter quality (chemical composition). Direct effects of WT regime, site nutrient regime and litter decomposition stage (length of incubation period) summed to only about 40 % of the litter type effect. WT regime alone explained about 5 % of the variation in enzyme activities and activity allocation. Generally, enzyme activity increased following the long-term WT drawdown and the activity allocation turned from P and N acquisition towards C

  18. Oscillator monitor

    International Nuclear Information System (INIS)

    McNeill, G.A.

    1981-01-01

    Present high-speed data acquisition systems in nuclear diagnostics use high-frequency oscillators to provide timing references for signals recorded on fast, traveling-wave oscilloscopes. An oscillator's sinusoidal wave shape is superimposed on the recorded signal with each cycle representing a fixed time increment. During data analysis the sinusoid is stripped from the signal, leaving a clean signal shape with known timing. Since all signal/time relationships are totally dependant upon working oscillators, these critical devices must have remote verification of proper operation. This manual presents the newly-developed oscillator monitor which will provide the required verification

  19. Assessment of denitrification gaseous end-products in the soil profile under two water table management practices using repeated measures analysis.

    Science.gov (United States)

    Elmi, Abdirashid A; Astatkie, Tess; Madramootoo, Chandra; Gordon, Robert; Burton, David

    2005-01-01

    The denitrification process and nitrous oxide (N2O) production in the soil profile are poorly documented because most research into denitrification has concentrated on the upper soil layer (0-0.15 m). This study, undertaken during the 1999 and 2000 growing seasons, was designed to examine the effects of water table management (WTM), nitrogen (N) application rate, and depth (0.15, 0.30, and 0.45 m) on soil denitrification end-products (N2O and N2) from a corn (Zea mays L.) field. Water table management treatments were free drainage (FD) with open drains and subirrigation (SI) with a target water table depth of 0.6 m. Fertility treatments (ammonium nitrate) were 120 kg N ha(-1) (N120) and 200 kg N ha(-1) (N200). During both growing seasons greater denitrification rates were measured in SI than in FD, particularly in the surface soil (0-0.15 m) and at the intermediate (0.15-0.30 m) soil depths under N200 treatment. Greater denitrification rates under the SI treatment, however, were not accompanied with greater N2O production. The decrease in N2O production under SI was probably caused by a more complete reduction of N2O to N2, which resulted in lower N2O to (N2O + N2) ratios. Denitrification rate, N2O production and N2O to (N2O + N2) ratios were only minimally affected by N treatments, irrespective of sampling date and soil depth. Overall, half of the denitrification occurred at the 0.15- to 0.30- and 0.30- to 0.45-m soil layers, and under SI, regardless of fertility treatment level. Consequently, sampling of the 0- to 0.15-m soil layer alone may not give an accurate estimation of denitrification losses under SI practice.

  20. Water-table and potentiometric-surface altitudes in the upper glacial, Magothy, and Lloyd aquifers of Long Island, New York, April–May 2016

    Science.gov (United States)

    Como, Michael D.; Finkelstein, Jason S.; Rivera, Simonette L.; Monti, Jack; Busciolano, Ronald J.

    2018-06-06

    The U.S. Geological Survey, in cooperation with State and local agencies, systematically collects groundwater data at varying measurement frequencies to monitor the hydrologic conditions on Long Island, New York. Each year during April and May, the U.S. Geological Survey completes a synoptic survey of water levels to define the spatial distribution of the water table and potentiometric surfaces within the three main water-bearing units underlying Long Island—the upper glacial, Magothy, and Lloyd aquifers—and the hydraulically connected Jameco and North Shore aquifers. These data and the maps constructed from them are commonly used in studies of the hydrology of Long Island and are used by water managers and suppliers for aquifer management and planning purposes.Water-level measurements made in 424 monitoring wells (observation and supply wells), 13 streamgages, and 2 lake gages across Long Island during April–May 2016 were used to prepare the maps in this report. Groundwater measurements were made by the wetted-tape or electric-tape method to the nearest hundredth of a foot. Contours of water-table and potentiometric-surface altitudes were created using the groundwater measurements. The water-table contours were interpreted using water-level data collected from 275 observation wells and 1 supply well screened in the upper glacial aquifer and the shallow Magothy aquifer and 13 streamgages and 2 lake gages. The potentiometric-surface contours of the Magothy aquifer were interpreted from measurements at 88 wells (61 observation wells and 27 supply wells) screened in the middle to deep Magothy aquifer and the contiguous and hydraulically connected Jameco aquifer. The potentiometric-surface contours of the Lloyd aquifer were interpreted from measurements at 60 wells (55 observation wells and 5 supply wells) screened in the Lloyd aquifer and the contiguous and hydraulically connected North Shore aquifer. Many of the supply wells are in continuous operation and

  1. Optimization of a predictive controller of a pressurized water reactor Xenon oscillation using the particle swarm optimization algorithm

    International Nuclear Information System (INIS)

    Medeiros, Jose Antonio Carlos Canedo; Machado, Marcelo Dornellas; Lima, Alan Miranda M. de; Schirru, Roberto

    2007-01-01

    Predictive control systems are control systems that use a model of the controlled system (plant), used to predict the future behavior of the plant allowing the establishment of an anticipative control based on a future condition of the plant, and an optimizer that, considering a future time horizon of the plant output and a recent horizon of the control action, determines the controller's outputs to optimize a performance index of the controlled plant. The predictive control system does not require analytical models of the plant; the model of predictor of the plant can be learned from historical data of operation of the plant. The optimizer of the predictive controller establishes the strategy of the control: the minimization of a performance index (objective function) is done so that the present and future control actions are computed in such a way to minimize the objective function. The control strategy, implemented by the optimizer, induces the formation of an optimal control mechanism whose effect is to reduce the stabilization time, the 'overshoot' and 'undershoot', minimize the control actuation so that a compromise among those objectives is attained. The optimizer of the predictive controller is usually implemented using gradient-based algorithms. In this work we use the Particle Swarm Optimization algorithm (PSO) in the optimizer component of a predictive controller applied in the control of the xenon oscillation of a pressurized water reactor (PWR). The PSO is a stochastic optimization technique applied in several disciplines, simple and capable of providing a global optimal for high complexity problems and difficult to be optimized, providing in many cases better results than those obtained by other conventional and/or other artificial optimization techniques. (author)

  2. Chromospheric oscillations

    NARCIS (Netherlands)

    Lites, B.W.; Rutten, R.J.; Thomas, J.H.

    1995-01-01

    We show results from SO/Sacramento Peak data to discuss three issues: (i)--the spatial occurrence of chromospheric 3--min oscillations; (ii)--the validity of Ca II H&K line-center Doppler Shift measurements; (iii)--the signi ?cance of oscillation power and phase at frequencies above 10 mHz.

  3. Inverted oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Yuce, C [Physics Department, Anadolu University, Eskisehir (Turkey); Kilic, A [Physics Department, Anadolu University, Eskisehir (Turkey); Coruh, A [Physics Department, Sakarya University, Sakarya (Turkey)

    2006-07-15

    The inverted harmonic oscillator problem is investigated quantum mechanically. The exact wavefunction for the confined inverted oscillator is obtained and it is shown that the associated energy eigenvalues are discrete, and the energy is given as a linear function of the quantum number n.

  4. Physico-chemical characteristics of the ground water table after monsoon: a case study at central Travancore in Kerala

    Directory of Open Access Journals (Sweden)

    Sankar S Vishnu

    2014-05-01

    Full Text Available Water quality plays an important role in maintaining plant and animal life. Lack of good quality drinking water and water for sanitation cause health problems. Water quality characteristics arise from a group of physical, chemical and biological factors. The dynamic balance of the aquatic system can be destroyed by human activities resulting in water pollution.Well water has traditionally considered as a safe resource of water for consumption without treatment and extensively used for individual water supply in rural and many urban areas.In this paper a preliminary analysis is done to explore the water quality of selected wells in order to correlate the effect of pollution on water quality at these locations. Water samples are collected from different regions of Vazhappally area located on central travancore of Kerala. These sites are important because people depend only on well water for drinking purpose. The samples are collected from ten locations and analyzed for chemical parameters such as pH, conductivity, salinity, turbidity, acidity, alkainity, hardness, total phosphates, dissolved oxygen, biological oxygen demand, total dissolved solids and Iron content. Samples are also analysed for coliform bacteria which cause pathogenic diseases. Remarkable differences are observed mainly in biological oxygen demand, acidity and hardness. Finally, an attempt has been done to correlate the observed chemical parameters and the waterquality standards. DOI: http://dx.doi.org/10.3126/ije.v3i2.10501 International Journal of the Environment Vol.3(2 2014: 20-27

  5. Modeling the potential impacts of climate change on the water table level of selected forested wetlands in the southeastern United States

    Directory of Open Access Journals (Sweden)

    J. Zhu

    2017-12-01

    Full Text Available The southeastern United States hosts extensive forested wetlands, providing ecosystem services including carbon sequestration, water quality improvement, groundwater recharge, and wildlife habitat. However, these wetland ecosystems are dependent on local climate and hydrology, and are therefore at risk due to climate and land use change. This study develops site-specific empirical hydrologic models for five forested wetlands with different characteristics by analyzing long-term observed meteorological and hydrological data. These wetlands represent typical cypress ponds/swamps, Carolina bays, pine flatwoods, drained pocosins, and natural bottomland hardwood ecosystems. The validated empirical models are then applied at each wetland to predict future water table changes using climate projections from 20 general circulation models (GCMs participating in Coupled Model Inter-comparison Project 5 (CMIP5 under the Representative Concentration Pathways (RCPs 4.5 and 8.5 scenarios. We show that combined future changes in precipitation and potential evapotranspiration would significantly alter wetland hydrology including groundwater dynamics by the end of the 21st century. Compared to the historical period, all five wetlands are predicted to become drier over time. The mean water table depth is predicted to drop by 4 to 22 cm in response to the decrease in water availability (i.e., precipitation minus potential evapotranspiration by the year 2100. Among the five examined wetlands, the depressional wetland in hot and humid Florida appears to be most vulnerable to future climate change. This study provides quantitative information on the potential magnitude of wetland hydrological response to future climate change in typical forested wetlands in the southeastern US.

  6. Modeling the potential impacts of climate change on the water table level of selected forested wetlands in the southeastern United States

    Science.gov (United States)

    Zhu, Jie; Sun, Ge; Li, Wenhong; Zhang, Yu; Miao, Guofang; Noormets, Asko; McNulty, Steve G.; King, John S.; Kumar, Mukesh; Wang, Xuan

    2017-12-01

    The southeastern United States hosts extensive forested wetlands, providing ecosystem services including carbon sequestration, water quality improvement, groundwater recharge, and wildlife habitat. However, these wetland ecosystems are dependent on local climate and hydrology, and are therefore at risk due to climate and land use change. This study develops site-specific empirical hydrologic models for five forested wetlands with different characteristics by analyzing long-term observed meteorological and hydrological data. These wetlands represent typical cypress ponds/swamps, Carolina bays, pine flatwoods, drained pocosins, and natural bottomland hardwood ecosystems. The validated empirical models are then applied at each wetland to predict future water table changes using climate projections from 20 general circulation models (GCMs) participating in Coupled Model Inter-comparison Project 5 (CMIP5) under the Representative Concentration Pathways (RCPs) 4.5 and 8.5 scenarios. We show that combined future changes in precipitation and potential evapotranspiration would significantly alter wetland hydrology including groundwater dynamics by the end of the 21st century. Compared to the historical period, all five wetlands are predicted to become drier over time. The mean water table depth is predicted to drop by 4 to 22 cm in response to the decrease in water availability (i.e., precipitation minus potential evapotranspiration) by the year 2100. Among the five examined wetlands, the depressional wetland in hot and humid Florida appears to be most vulnerable to future climate change. This study provides quantitative information on the potential magnitude of wetland hydrological response to future climate change in typical forested wetlands in the southeastern US.

  7. Chemical Oscillations

    Indian Academy of Sciences (India)

    IMTECH),. Chandigarh. Praveen Kumar is pursuing his PhD in chemical dynamics at. Panjab University,. Chandigarh. Keywords. Chemical oscillations, autoca-. talYSis, Lotka-Volterra model, bistability, hysteresis, Briggs-. Rauscher reaction.

  8. Chemical Oscillations

    Indian Academy of Sciences (India)

    the law of mass-action that every simple reaction approaches ... from thermodynamic equilibrium. Such oscillating systems cor- respond to thermodynamically open systems. .... experimentally observable, and the third is always unstable.

  9. Paleohydrology of the southern Great Basin, with special reference to water table fluctuations beneath the Nevada Test Site during the late(?) Pleistocene

    Science.gov (United States)

    Winograd, Isaac Judah; Doty, Gene C.

    1980-01-01

    Knowledge of the magnitude of water-table rise during Pleistocene pluvial climates, and of the resultant shortening of groundwater flow path and reduction in unsaturated zone thickness, is mandatory for a technical evaluation of the Nevada Test Site (NTS) or other arid zone sites as repositories for high-level or transuranic radioactive wastes. The distribution of calcitic veins filling fractures in alluvium, and of tufa deposits between the Ash Meadows spring discharge area and the Nevada Test Site indicates that discharge from the regional Paleozoic carbonate aquifer during the Late( ) Pleistocene pluvial periods may have occurred at an altitude about 50 meters higher than at present and 14 kilometers northeast of Ash Meadows. Use of the underflow equation (relating discharge to transmissivity, aquifer width, and hydraulic gradient), and various assumptions regarding pluvial recharge, transmissivity, and altitude of groundwater base level, suggest possible rises in potentiometric level in the carbonate aquifer of about -90 meters beneath central Frenchman Flat. During Wisconsin time the rise probably did not exceed 30 meters. Water-level rises beneath Frenchman Flat during future pluvials are unlikely to exceed 30 meters and might even be 10 meters lower than modern levels. Neither the cited rise in potentiometric level in the regional carbonate aquifer, nor the shortened flow path during the Late( ) Pleistocene preclude utilization of the NTS as a repository for high-level or transuranic-element radioactive wastes provided other requisite conditions are met as this site. Deep water tables, attendant thick (up to several hundred meter) unsaturated zones, and long groundwater flow paths characterized the region during the Wisconsin Stage and probably throughout the Pleistocene Epoch and are likely to so characterize it during future glacial periods. (USGS)

  10. Water-table altitude of the unconfined aquifer, Wood River Valley aquifer system, south-central Idaho, October 2012.

    Data.gov (United States)

    Department of the Interior — Water levels in 93 wells completed in the Wood River Valley aquifer system were measured during October 22–24, 2012; these wells are part of a network established...

  11. Detection of the adsorption of water monolayers through the ion oscillation frequency in the magnesium oxide lattice by means of low energy electron diffraction

    Directory of Open Access Journals (Sweden)

    M. Guevara-Bertsch

    2016-03-01

    Full Text Available We investigate the variation of the oscillation frequency of the Mg2+ and O2− ions in the magnesium oxide lattice due to the interactions of the surface with water monolayers by means of Low Energy Electron Diffraction. Our key result is a new technique to determine the adsorbate vibrations produced by the water monolayers on the surface lattice as a consequence of their change in the surface Debye temperature and its chemical shift. The latter was systematically investigated for different annealing times and for a constant external thermal perturbation in the range of 110–300 K in order to accomplish adsorption or desorption of water monolayers in the surface lattice.

  12. Detection of the adsorption of water monolayers through the ion oscillation frequency in the magnesium oxide lattice by means of low energy electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Guevara-Bertsch, M.; Avendaño, E. [Escuela de Física, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Ramírez-Hidalgo, G. [Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Sección de Física Teórica, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Chavarría-Sibaja, A.; Araya-Pochet, J. A. [Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Herrera-Sancho, O. A., E-mail: oscar-andrey.herrera@uibk.ac.at [Escuela de Física, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstr. 21a, 6020 Innsbruck (Austria)

    2016-03-15

    We investigate the variation of the oscillation frequency of the Mg{sup 2+} and O{sup 2−} ions in the magnesium oxide lattice due to the interactions of the surface with water monolayers by means of Low Energy Electron Diffraction. Our key result is a new technique to determine the adsorbate vibrations produced by the water monolayers on the surface lattice as a consequence of their change in the surface Debye temperature and its chemical shift. The latter was systematically investigated for different annealing times and for a constant external thermal perturbation in the range of 110–300 K in order to accomplish adsorption or desorption of water monolayers in the surface lattice.

  13. Comparison of the Experimental and Numerical Results of Modelling a 32-Oscillating Water Column (OWC, V-Shaped Floating Wave Energy Converter

    Directory of Open Access Journals (Sweden)

    John V. Ringwood

    2013-08-01

    Full Text Available Combining offshore wind and wave energy converting apparatuses presents a number of potentially advantageous synergies. To facilitate the development of a proposed floating platform combining these two technologies, proof of concept scale model testing on the wave energy converting component of this platform has been conducted. The wave energy component is based on the well-established concept of the oscillating water column. A numerical model of this component has been developed in the frequency domain, and the work presented here concerns the results of this modelling and testing. The results of both are compared to assess the validity and usefulness of the numerical model.

  14. Oscillating acoustic streaming jet

    International Nuclear Information System (INIS)

    Moudjed, Brahim; Botton, Valery; Henry, Daniel; Millet, Severine; Ben Hadid, Hamda; Garandet, Jean-Paul

    2014-01-01

    The present paper provides the first experimental investigation of an oscillating acoustic streaming jet. The observations are performed in the far field of a 2 MHz circular plane ultrasound transducer introduced in a rectangular cavity filled with water. Measurements are made by Particle Image Velocimetry (PIV) in horizontal and vertical planes near the end of the cavity. Oscillations of the jet appear in this zone, for a sufficiently high Reynolds number, as an intermittent phenomenon on an otherwise straight jet fluctuating in intensity. The observed perturbation pattern is similar to that of former theoretical studies. This intermittently oscillatory behavior is the first step to the transition to turbulence. (authors)

  15. Three-dimensional hydrogeological modeling to assess the elevated-water-table technique for controlling acid generation from an abandoned tailings site in Quebec, Canada

    Science.gov (United States)

    Ethier, Marie-Pier; Bussière, Bruno; Broda, Stefan; Aubertin, Michel

    2018-01-01

    The Manitou Mine sulphidic-tailings storage facility No. 2, near Val D'Or, Canada, was reclaimed in 2009 by elevating the water table and applying a monolayer cover made of tailings from nearby Goldex Mine. Previous studies showed that production of acid mine drainage can be controlled by lowering the oxygen flux through Manitou tailings with a water table maintained at the interface between the cover and reactive tailings. Simulations of different scenarios were performed using numerical hydrogeological modeling to evaluate the capacity of the reclamation works to maintain the phreatic surface at this interface. A large-scale numerical model was constructed and calibrated using 3 years of field measurements. This model reproduced the field measurements, including the existence of a western zone on the site where the phreatic level targeted is not always met during the summer. A sensitivity analysis was performed to assess the response of the model to varying saturated hydraulic conductivities, porosities, and grain-size distributions. Higher variations of the hydraulic heads, with respect to the calibrated scenario results, were observed when simulating a looser or coarser cover material. Long-term responses were simulated using: the normal climatic data, data for a normal climate with a 2-month dry spell, and a simplified climate-change case. Environmental quality targets were reached less frequently during summer for the dry spell simulation as well as for the simplified climate-change scenario. This study illustrates how numerical simulations can be used as a key tool to assess the eventual performance of various mine-site reclamation scenarios.

  16. Scots pine (Pinus sylvestris L.) based reconstruction of 130 years of water table fluctuations in a peatland and its relevance for moisture variability assessments

    Science.gov (United States)

    Tamkevičiūtė, Marija; Edvardsson, Johannes; Pukienė, Rūtilė; Taminskas, Julius; Stoffel, Markus; Corona, Christophe; Kibirkštis, Gintautas

    2018-03-01

    Continuous water-table (WT) measurements from peatlands are scarce and - if existing at all -very short. Consequently, proxy indicators are critically needed to simulate hydrological changes in peatlands over longer time periods. In this study, we demonstrate that tree-ring width (TRW) records of Scots pine (Pinus sylvestris L.) growing in the Čepkeliai peatland (southern Lithuania) can be used as a proxy to reconstruct hydrological variability in a raised bog environment. A two-step modelling procedure was applied to extend existing measurements and to develop a new and longer peatland WT time series. To this end, we used instrumental WT measurements extending back to 2002, meteorological records, a P-PET (difference between precipitation and potential evapotranspiration) series covering the period 1935-2014, so as to construct a tree-ring based time series of WT fluctuations at the site for the period 1870-2014. Strongest correlations were obtained between average annual WT measured at the bog margin and total P-PET over 7 years (r = 0.923, p runoff since CE 1812 (r = 0.39, p < 0.00001, 1870-2014). We conclude that peatlands can act both as sinks and sources of greenhouse gases in case that hydrological conditions change, but that hydrological lags and complex feedbacks still hamper our understanding of several processes affecting the hydrology and carbon budget in peatlands. We therefore call for the development of further proxy records of water-table variability in peatlands to improve our understanding of peatland responses to climatic changes.

  17. Estimation of bare soil evaporation for different depths of water table in the wind-blown sand area of the Ordos Basin, China

    Science.gov (United States)

    Chen, Li; Wang, Wenke; Zhang, Zaiyong; Wang, Zhoufeng; Wang, Qiangmin; Zhao, Ming; Gong, Chengcheng

    2018-04-01

    Soil surface evaporation is a significant component of the hydrological cycle, occurring at the interface between the atmosphere and vadose zone, but it is affected by factors such as groundwater level, soil properties, solar radiation and others. In order to understand the soil evaporation characteristics in arid regions, a field experiment was conducted in the Ordos Basin, central China, and high accuracy sensors of soil moisture, moisture potential and temperature were installed in three field soil profiles with water-table depths (WTDs) of about 0.4, 1.4 and 2.2 m. Soil-surface-evaporation values were estimated by observed data combined with Darcy's law. Results showed that: (1) soil-surface-evaporation rate is linked to moisture content and it is also affected by air temperature. When there is sufficient moisture in the soil profile, soil evaporation increases with rising air temperature. For a WTD larger than the height of capillary rise, the soil evaporation is related to soil moisture content, and when air temperature is above 25 °C, the soil moisture content reduces quickly and the evaporation rate lowers; (2) phreatic water contributes to soil surface evaporation under conditions in which the WTD is within the capillary fringe. This indicates that phreatic water would not participate in soil evaporation for a WTD larger than the height of capillary rise. This finding developed further the understanding of phreatic evaporation, and this study provides valuable information on recognized soil evaporation processes in the arid environment.

  18. Nonlinear oscillations

    CERN Document Server

    Nayfeh, Ali Hasan

    1995-01-01

    Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

  19. Physiological and morphological effects of high water tables on early growth of giant reed (Arundo donax), elephant grass (Pennisetum purpureum), energycane and sugarcane (Saccharum spp.)

    Energy Technology Data Exchange (ETDEWEB)

    Jennewein, Stephen Peter [Univ. of Florida, Gainesville, FL (United States)

    2013-01-01

    Here, an increasing demand for renewable energy sources has spurred interest in high-biomass crops used for energy production. Species potentially well-suited for biofuel production in the seasonally wet organic Everglades Agricultural Area (EAA) of Florida include giant reed (Arundo donax), elephant grass (Pennisetum Purpureum), energycane (Saccharum spp.), and sugarcane (Saccharum spp.). The objectives in this study were to evaluate the role of fluctuating water tables on the morphology, physiology, and early season growth of these four genotypes. The candidate genotypes were grown in a greenhouse under three water table depths, defined by distance of the water table from the soil surface: two constant water tables (-16 cm and -40 cm) along with a flood cycle (2 weeks of flood to the soil level followed by 2 weeks at -40 cm from the soil level). The genotypes included CP 89-2143 (sugarcane), L 79-1002 (energycane), Merkeron (elephant grass), and wild type (giant reed). The experiment was repeated for plant cane, first ratoon, and successive plant cane crop cycles. Reductions in dry matter yield were observed among genotypes subjected to the -40 cm drained, periodically flooded (40F) water table relative to the -40 cm constant (40C) or -16 cm constant (16C). Plant cane dry weights were reduced by 37% in giant reed, 52% in elephant grass, 42% in energycane, and 34% in sugarcane in the 40F compared to 40C water table treatments. Similarly, in the first ratoon crop dry weights were reduced by 29% in giant reed, 42% in elephant grass, 27% in energycane, and 62% in sugarcane. In plant cane and successive plant cane, average total dry weight was greatest for elephant grass whereas ratoon total dry weight was greatest for energycane. Genotype had more pronounced effects on physiological attributes than water table including the highest stomatal conductance and SPAD values in giant reed, and the highest stalk populations in elephant grass and

  20. El Niño-Southern Oscillation and water resources in the headwaters region of the Yellow River: links and potential for forecasting

    Directory of Open Access Journals (Sweden)

    A. Lü

    2011-04-01

    Full Text Available This research explores the rainfall-El Niño-Southern Oscillation (ENSO and runoff-ENSO relationships and examines the potential for water resource forecasting using these relationships. The Southern Oscillation Index (SOI, Niño1.2, Niño3, Niño4, and Niño3.4 were selected as ENSO indicators for cross-correlation analyses of precipitation and runoff. There was a significant correlation (95% confidence level between precipitation and ENSO indicators during three periods: January, March, and from September to November. In addition, monthly streamflow and monthly ENSO indictors were significantly correlated during three periods: from January to March, June, and from October to December (OND, with lag periods between one and twelve months. Because ENSO events can be accurately predicted one to two years in advance using physical modeling of the coupled ocean-atmosphere system, the lead time for forecasting runoff using ENSO indicators in the Headwaters Region of the Yellow River could extend from one to 36 months. Therefore, ENSO may have potential as a powerful forecasting tool for water resources in the headwater regions of Yellow River.

  1. Fluctuating water table affects gross ecosystem production and gross radiation use efficiency in a sedge-grass marsh

    Czech Academy of Sciences Publication Activity Database

    Dušek, Jiří; Čížková, Hana; Stellner, Stanislav; Czerný, Radek; Květ, Jan

    2012-01-01

    Roč. 692, č. 1 (2012), s. 57-66 ISSN 0018-8158 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŽP(CZ) SP/2D1/93/07; GA MŠk OC08021 Institutional research plan: CEZ:AV0Z60870520 Keywords : Wetland * fen * carbon * water level * Carex acuta L. * Eddy covariance Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.985, year: 2012

  2. Water

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2010-08-01

    Full Text Available Water scarcity is without a doubt on of the greatest threats to the human species and has all the potential to destabilise world peace. Falling water tables are a new phenomenon. Up until the development of steam and electric motors, deep groudwater...

  3. Efecto del agua aplicada en las relaciones hídricas y productividad de la vid 'Crimson Seedless' Effect of applied water on water relations and productivity of 'Crimson Seedless' table grapes

    Directory of Open Access Journals (Sweden)

    Raúl Ferreyra

    2006-07-01

    Full Text Available Este estudio fue dirigido para evaluar la relación agua-rendimiento en vid de mesa cv. Crimson y establecer valores críticos para las mediciones del estado hídrico de las plantas. Los estudios de campo se desarrollaron durante tres años, en el Valle de Aconcagua, Chile, a 32º47'S y 70º42'O, en un suelo de textura franco arcillosa. Se proporcionaron a las plantas diferentes cantidades de agua de riego entre 40 y 100% de la evapotranspiración del cultivo (Etc. El potencial hídrico xilemático medido a mediodía (psixmin y la conductancia estomática estuvieron estrechamente relacionados con el déficit de agua impuesto y el rendimiento obtenido. Los rendimientos de la vid disminuyeron respecto al agua aplicada en el rango de los tratamientos estudiados. Sesenta por ciento de restricción de la Etc redujo 22% del rendimiento. Cuando la planta mantuvo psixmin mayor que -0,75 MPa entre cuaja y pinta, la producción y los calibres fueron mayores.This study aimed to evaluate the relationship between water and production in 'Crimson Seedless' table grapes, and to establish threshold values for plants water status. Field experiments were carried out, during a three-year period, in the Aconcagua Valley, Chile, at 32º47'S and 70º42'W, in a clay-loamy textured soil. Different irrigation water amounts were applied, between 40 and 100% crop evapotranspiration (Etc. Stem water potential measured at midday (psixmin and stomatal conductance were closely related to water shortage and yield obtained. Table grape yields decreased in comparison with applied water within the range of studied treatments. Sixty per cent Etc restriction decreased yields in 22%. When plants maintained psixmin greater than -0.75 MPa, between berry set and veraison, yield and berry size were high.

  4. Elastic oscillations of water column in the 2003 Tokachi-oki tsunami source: in-situ measurements and 3-D numerical modelling

    Directory of Open Access Journals (Sweden)

    M. A. Nosov

    2007-01-01

    Full Text Available During the 2003 Tokachi-Oki tsunamigenic earthquake the real-time JAMSTEC observatory obtained records which provided a unique opportunity to have a look deep inside the tsunami source. Considering water column as a compressible medium we processed the bottom pressure records in order to estimate amplitude, duration and velocity of bottom displacement. Spectral analysis of the records revealed a clear manifestation of the low-frequency elastic oscillations of water column. We also presented 3-D finite-difference numerical model developed in the framework of linear potential theory of ideal compressible fluid to better understand dynamical processes in the tsunami source. The model reproduces position of the main spectral maximum rather correctly. However, due to neglecting of crust elasticity and to lack of exact knowledge of spatiotemporal laws of bottom motion, there is an essential difference between in-situ observed and computed spectra.

  5. Power-level regulation and simulation of nonlinear pressurized water reactor core with xenon oscillation using H-infinity loop shaping control

    Directory of Open Access Journals (Sweden)

    Li Gang

    2016-01-01

    Full Text Available This investigation is to solve the power-level control issue of a nonlinear pressurized water reactor core with xenon oscillations. A nonlinear pressurized water reactor core is modeled using the lumped parameter method, and a linear model of the core is then obtained through the small perturbation linearization way. The H∞loop shapingcontrolis utilized to design a robust controller of the linearized core model.The calculated H∞loop shaping controller is applied to the nonlinear core model. The nonlinear core model and the H∞ loop shaping controller build the nonlinear core power-level H∞loop shaping control system.Finally, the nonlinear core power-level H∞loop shaping control system is simulatedconsidering two typical load processes that are a step load maneuver and a ramp load maneuver, and simulation results show that the nonlinear control system is effective.

  6. Pulse radiolysis of liquid water using picosecond electron pulses produced by a table-top terawatt laser system

    International Nuclear Information System (INIS)

    Saleh, Ned; Flippo, Kirk; Nemoto, Koshichi; Umstadter, Donald; Crowell, Robert A.; Jonah, Charles D.; Trifunac, Alexander D.

    2000-01-01

    A laser based electron generator is shown, for the first time, to produce sufficient charge to conduct time resolved investigations of radiation induced chemical events. Electron pulses generated by focussing terawatt laser pulses into a supersonic helium gas jet are used to ionize liquid water. The decay of the hydrated electrons produced by the ionizing electron pulses is monitored with 0.3 μs time resolution. Hydrated electron concentrations as high as 22 μM were generated. The results show that terawatt lasers offer both an alternative to linear accelerators and a means to achieve subpicosecond time resolution for pulse radiolysis studies. (c) 2000 American Institute of Physics

  7. VIDENTE: a graphical user interface and decision support system for stochastic modelling of water table fluctuations at a single location; includes documentation of the programs KALMAX, KALTFN, SSD and EMERALD and introductions to stochastic modellin

    NARCIS (Netherlands)

    Bierkens, M.F.P.; Bron, W.A.

    2000-01-01

    The VIDENTE program contains a decision support system (DSS) to choose between different models for stochastic modelling of water-table depths, and a graphical user interface to facilitate operating and running four implemented models: KALMAX, KALTFN,SSDS and EMERALD. In self-contained parts each of

  8. Monthly tables of measurements. October 2000

    International Nuclear Information System (INIS)

    2000-10-01

    This report of the O.P.R.I. (Office of Protection against Ionizing Radiations) exposes the principal results concerning the routine monitoring of environmental radioactivity in France: atmospheric dusts, rainwater, surface water, underground water, sewage water, drinking water, food chain (milk, vegetables, fishes), sea water around nuclear sites and other sites. The activities of various radioisotopes are presented in tables. (N.C.)

  9. Water

    International Nuclear Information System (INIS)

    Chovanec, A.; Grath, J.; Kralik, M.; Vogel, W.

    2002-01-01

    An up-date overview of the situation of the Austrian waters is given by analyzing the status of the water quality (groundwater, surface waters) and water protection measures. Maps containing information of nitrate and atrazine in groundwaters (analyses at monitoring stations), nitrate contents and biological water quality of running waters are included. Finally, pollutants (nitrate, orthophosphate, ammonium, nitrite, atrazine etc.) trends in annual mean values and median values for the whole country for the years 1992-1999 are presented in tables. Figs. 5. (nevyjel)

  10. Coupled eco-hydrology and biogeochemistry algorithms enable the simulation of water table depth effects on boreal peatland net CO2 exchange

    Science.gov (United States)

    Mezbahuddin, Mohammad; Grant, Robert F.; Flanagan, Lawrence B.

    2017-12-01

    Water table depth (WTD) effects on net ecosystem CO2 exchange of boreal peatlands are largely mediated by hydrological effects on peat biogeochemistry and the ecophysiology of peatland vegetation. The lack of representation of these effects in carbon models currently limits our predictive capacity for changes in boreal peatland carbon deposits under potential future drier and warmer climates. We examined whether a process-level coupling of a prognostic WTD with (1) oxygen transport, which controls energy yields from microbial and root oxidation-reduction reactions, and (2) vascular and nonvascular plant water relations could explain mechanisms that control variations in net CO2 exchange of a boreal fen under contrasting WTD conditions, i.e., shallow vs. deep WTD. Such coupling of eco-hydrology and biogeochemistry algorithms in a process-based ecosystem model, ecosys, was tested against net ecosystem CO2 exchange measurements in a western Canadian boreal fen peatland over a period of drier-weather-driven gradual WTD drawdown. A May-October WTD drawdown of ˜ 0.25 m from 2004 to 2009 hastened oxygen transport to microbial and root surfaces, enabling greater microbial and root energy yields and peat and litter decomposition, which raised modeled ecosystem respiration (Re) by 0.26 µmol CO2 m-2 s-1 per 0.1 m of WTD drawdown. It also augmented nutrient mineralization, and hence root nutrient availability and uptake, which resulted in improved leaf nutrient (nitrogen) status that facilitated carboxylation and raised modeled vascular gross primary productivity (GPP) and plant growth. The increase in modeled vascular GPP exceeded declines in modeled nonvascular (moss) GPP due to greater shading from increased vascular plant growth and moss drying from near-surface peat desiccation, thereby causing a net increase in modeled growing season GPP by 0.39 µmol CO2 m-2 s-1 per 0.1 m of WTD drawdown. Similar increases in GPP and Re caused no significant WTD effects on modeled

  11. Coupled eco-hydrology and biogeochemistry algorithms enable the simulation of water table depth effects on boreal peatland net CO2 exchange

    Directory of Open Access Journals (Sweden)

    M. Mezbahuddin

    2017-12-01

    Full Text Available Water table depth (WTD effects on net ecosystem CO2 exchange of boreal peatlands are largely mediated by hydrological effects on peat biogeochemistry and the ecophysiology of peatland vegetation. The lack of representation of these effects in carbon models currently limits our predictive capacity for changes in boreal peatland carbon deposits under potential future drier and warmer climates. We examined whether a process-level coupling of a prognostic WTD with (1 oxygen transport, which controls energy yields from microbial and root oxidation–reduction reactions, and (2 vascular and nonvascular plant water relations could explain mechanisms that control variations in net CO2 exchange of a boreal fen under contrasting WTD conditions, i.e., shallow vs. deep WTD. Such coupling of eco-hydrology and biogeochemistry algorithms in a process-based ecosystem model, ecosys, was tested against net ecosystem CO2 exchange measurements in a western Canadian boreal fen peatland over a period of drier-weather-driven gradual WTD drawdown. A May–October WTD drawdown of  ∼  0.25 m from 2004 to 2009 hastened oxygen transport to microbial and root surfaces, enabling greater microbial and root energy yields and peat and litter decomposition, which raised modeled ecosystem respiration (Re by 0.26 µmol CO2 m−2 s−1 per 0.1 m of WTD drawdown. It also augmented nutrient mineralization, and hence root nutrient availability and uptake, which resulted in improved leaf nutrient (nitrogen status that facilitated carboxylation and raised modeled vascular gross primary productivity (GPP and plant growth. The increase in modeled vascular GPP exceeded declines in modeled nonvascular (moss GPP due to greater shading from increased vascular plant growth and moss drying from near-surface peat desiccation, thereby causing a net increase in modeled growing season GPP by 0.39 µmol CO2 m−2 s−1 per 0.1 m of WTD drawdown. Similar increases in

  12. Stability analysis of roadway embankments supported by stone columns with the presence of water table under short-term and long-term conditions

    Directory of Open Access Journals (Sweden)

    Kadhim Shaymaa Tareq

    2018-01-01

    Full Text Available Use of stone column technique to improve soft foundation soils under roadway embankments has proven to increase the bearing capacity and reduce the potential settlement. The potential contribution of stone columns to the stability of roadway embankments against general (i.e. deep-seated failure needs to be thoroughly investigated. Therefore, a two-dimensional finite difference model implemented by FLAC/SLOPE 7.0 software, was employed in this study to assess the stability of a roadway embankment fill built on a soft soil deposit improved by stone column technique. The stability factor of safety was obtained numerically under both short-term and long-term conditions with the presence of water table. Two methods were adopted to convert the three-dimensional model into plane strain condition: column wall and equivalent improved ground methods. The effect of various parameters was studied to evaluate their influence on the factor of safety against embankment instability. For instance, the column diameter, columns’ spacing, soft soil properties for short-term and long-term conditions, and the height and friction angle of the embankment fill. The results of this study are developed in several design charts.

  13. Water-table and discharge changes associated with the 2016-2017 seismic sequence in central Italy: hydrogeological data and a conceptual model for fractured carbonate aquifers

    Science.gov (United States)

    Petitta, Marco; Mastrorillo, Lucia; Preziosi, Elisabetta; Banzato, Francesca; Barberio, Marino Domenico; Billi, Andrea; Cambi, Costanza; De Luca, Gaetano; Di Carlo, Giuseppe; Di Curzio, Diego; Di Salvo, Cristina; Nanni, Torquato; Palpacelli, Stefano; Rusi, Sergio; Saroli, Michele; Tallini, Marco; Tazioli, Alberto; Valigi, Daniela; Vivalda, Paola; Doglioni, Carlo

    2018-01-01

    A seismic sequence in central Italy from August 2016 to January 2017 affected groundwater dynamics in fractured carbonate aquifers. Changes in spring discharge, water-table position, and streamflow were recorded for several months following nine Mw 5.0-6.5 seismic events. Data from 22 measurement sites, located within 100 km of the epicentral zones, were analyzed. The intensity of the induced changes were correlated with seismic magnitude and distance to epicenters. The additional post-seismic discharge from rivers and springs was found to be higher than 9 m3/s, totaling more than 0.1 km3 of groundwater release over 6 months. This huge and unexpected contribution increased streamflow in narrow mountainous valleys to previously unmeasured peak values. Analogously to the L'Aquila 2009 post-earthquake phenomenon, these hydrogeological changes might reflect an increase of bulk hydraulic conductivity at the aquifer scale, which would increase hydraulic heads in the discharge zones and lower them in some recharge areas. The observed changes may also be partly due to other mechanisms, such as shaking and/or squeezing effects related to intense subsidence in the core of the affected area, where effects had maximum extent, or breaching of hydraulic barriers.

  14. Experiments of flow-induced in-line oscillation of a circular cylinder in a water tunnel. 2. Influence of the aspect ratio of a cantilevered circular cylinder

    International Nuclear Information System (INIS)

    Nakamura, Akira; Okajima, Atsushi; Kosugi, Takashi

    2001-01-01

    The flow-induced in-line oscillation of a cantilevered circular cylinder was experimentally studied through free-oscillation tests in a water tunnel. The response displacement amplitude at a circular cylinder tip was measured at reduced velocity from 1.0 to 4.0. A cantilevered cylinder was supported by a plate spring mounted on the water tunnel wall. The cylinder aspect ratio was varied from 5 to 21 to investigate the effect of aspect ratio on the response displacement. It is found that cylinders with aspect ratios of 5 and 10 have one excitation region, while cylinders with aspect ratios of 14 and 21 have two excitation regions. The aspect ratio, therefore, affects the amplitude of the excitation regions. The influence of end-effect was also investigated using cylinders with an end plate attached to the free end. Since the cylinders with an end plate show two excitation regions, even at an aspect ratio of 5, the flow around the free end of a cantilevered cylinder causes the end-effect. The mechanism of vibration was investigated using a cylinder with a splitter plate in wake to prevent alternate vortices. The amplitude is greater than those of a normal cylinder without a splitter plate, especially at V r =2.3 to 3.0, where a cylinder with an end plate shows the second excitation region. In order words, the alternate vortices suppress the amplitude in this range. The maximum amplitude of each excitation region decreases in proportion to C n and the amplitude of the first excitation is more sensitive to C n . (author)

  15. Oscillator circuits

    CERN Document Server

    Graf, Rudolf F

    1996-01-01

    This series of circuits provides designers with a quick source for oscillator circuits. Why waste time paging through huge encyclopedias when you can choose the topic you need and select any of the specialized circuits sorted by application?This book in the series has 250-300 practical, ready-to-use circuit designs, with schematics and brief explanations of circuit operation. The original source for each circuit is listed in an appendix, making it easy to obtain additional information.Ready-to-use circuits.Grouped by application for easy look-up.Circuit source listing

  16. Crop water parameters of irrigated wine and table grapes to support water productivity analysis in the Sao Francisco river basin, Brazil

    NARCIS (Netherlands)

    Castro Teixeira, de A.H.; Bastiaanssen, W.G.M.; Bassoi, L.H.

    2007-01-01

    Energy and water balance parameters were measured in two commercial vineyards in the semiarid region of the São Francisco river basin, Brazil. Actual evapotranspiration (ET) was acquired with the Bowen ratio surface energy balance method. The ratio of the latent heat flux to the available energy, or

  17. On the Modeling of Local Neutronically-Coupled Flow-Induced Oscillations in Advanced Boiling Water Reactors

    International Nuclear Information System (INIS)

    Aniel-Buchheit, Sylvie; Podowski, Michael Z.

    2006-01-01

    The purpose of this paper is to discuss the development in progress of a complete space- and time-dependent model of the coupled neutron kinetic and reactor thermal-hydraulics. The neutron kinetics model is based on two-group diffusion equations with Doppler and void reactivity feedback effects. This model is coupled with the model of two-phase flow and heat transfer in parallel coolant channels. The modeling concepts considered for this purpose include one-dimensional drift flux and two-fluid models, as well a CFD model implemented in the NPHASE advanced computational multiphase fluid dynamics (CMFD) computer code. Two methods of solution for the overall model are proposed. One is based on direct numerical integration of the spatially-discretized governing equations. The other approach is based on a quasi-analytical modal approach to the neutronics model, in which a complete set of eigenvectors is found for step-wise temporal changes of the cross-sections of core materials (fuel and coolant/moderator). The issues investigated in the paper include details of model formulation, as well as the results of calculations for neutronically-coupled density-wave oscillations. (authors)

  18. Dynamics of Soil Water Evaporation during Soil Drying in the Presence of a Shallow Water Table: Laboratory Experiment and Numerical Analysis

    Science.gov (United States)

    Han, J.; Lin, J.; Liu, P.; Li, W.

    2017-12-01

    Evaporation from a porous medium plays a key role in hydrological, agricultural, environmental, and engineering applications. Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68 cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71 cm during stage 3. Although the magnitude of condensation zone was much smaller than that for the evaporation zone, the importance of the contribution of condensation zone to soil water dynamics should not be underestimated. Results from our experiment and numerical simulation show that this condensation process resulted in an unexpected and apparent water content increase in the middle of vadose zone profile.

  19. One dimension harmonic oscillator

    International Nuclear Information System (INIS)

    Cohen-Tannoudji, Claude; Diu, Bernard; Laloe, Franck.

    1977-01-01

    The importance of harmonic oscillator in classical and quantum physics, eigenvalues and eigenstates of hamiltonian operator are discussed. In complement are presented: study of some physical examples of harmonic oscillators; study of stationnary states in the /x> representation; Hermite polynomials; resolution of eigenvalue equation of harmonic oscillator by polynomial method; isotope harmonic oscillator with three dimensions; charged harmonic oscillator in uniform electric field; quasi classical coherent states of harmonic oscillator; eigenmodes of vibration of two coupled harmonic oscillators; vibration modus of a continuous physical system (application to radiation: photons); vibration modus of indefinite linear chain of coupled harmonic oscillators (phonons); one-dimensional harmonic oscillator in thermodynamic equilibrium at temperature T [fr

  20. Power oscillation damping controller

    DEFF Research Database (Denmark)

    2012-01-01

    A power oscillation damping controller is provided for a power generation device such as a wind turbine device. The power oscillation damping controller receives an oscillation indicating signal indicative of a power oscillation in an electricity network and provides an oscillation damping control...

  1. Oscillations of void lattices

    International Nuclear Information System (INIS)

    Akhiezer, A.I.; Davydov, L.N.; Spol'nik, Z.A.

    1976-01-01

    Oscillations of a nonideal crystal are studied, in which macroscopic defects (pores) form a hyperlattice. It is shown that alongside with acoustic and optical phonons (relative to the hyperlattice), in such a crystal oscillations of the third type are possible which are a hydridization of sound oscillations of atoms and surface oscillations of a pore. Oscillation spectra of all three types were obtained

  2. Geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples, and its possible relationship with the prevalence of enamel fluorosis in children in four municipalities of the department of Huila (Colombia).

    Science.gov (United States)

    Martignon, Stefania; Opazo-Gutiérrez, Mario Omar; Velásquez-Riaño, Möritz; Orjuela-Osorio, Iván Rodrigo; Avila, Viviana; Martinez-Mier, Esperanza Angeles; González-Carrera, María Clara; Ruiz-Carrizosa, Jaime Alberto; Silva-Hermida, Blanca Cecilia

    2017-06-01

    Fluoride is an element that affects teeth and bone formation in animals and humans. Though the use of systemic fluoride is an evidence-based caries preventive measure, excessive ingestion can impair tooth development, mainly the mineralization of tooth enamel, leading to a condition known as enamel fluorosis. In this study, we investigated the geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples in four endemic enamel fluorosis sentinel municipalities of the department of Huila, Colombia (Pitalito, Altamira, El Agrado and Rivera), and its possible relationship with the prevalence of enamel fluorosis in children. The concentration of fluoride in drinking water, table salt, active sediment, rock, and soil was evaluated by means of an ion selective electrode and the geochemical analyses were performed using X-ray fluorescence. Geochemical analysis revealed fluoride concentrations under 15 mg/kg in active sediment, rock and soil samples, not indicative of a significant delivery to the watersheds studied. The concentration of fluoride in table salt was found to be under the inferior limit (less than 180 μg/g) established by the Colombian regulations. Likewise, exposure doses for fluoride water intake did not exceed the recommended total dose for all ages from 6 months. Although the evidence does not point out at rocks, soils, fluoride-bearing minerals, fluoridated salt and water, the hypothesis of these elements as responsible of the current prevalence of enamel fluorosis cannot be discarded since, aqueducts might have undergone significant changes overtime.

  3. Decadal oscillation of lakes and aquifers in the upper Great Lakes region of North America: hydroclimatic implications

    Science.gov (United States)

    Watras, C.J.; Read, J.S.; Holman, K.D.; Liu, Z.; Song, Y.-Y.; Watras, A.J.; Morgan, S.; Stanley, E.H.

    2014-01-01

    We report a unique hydrologic time-series which indicates that water levels in lakes and aquifers across the upper Great Lakes region of North America have been dominated by a climatically-driven, near-decadal oscillation for at least 70 years. The historical oscillation (~13y) is remarkably consistent among small seepage lakes, groundwater tables and the two largest Laurentian Great Lakes despite substantial differences in hydrology. Hydrologic analyses indicate that the oscillation has been governed primarily by changes in the net atmospheric flux of water (P-E) and stage-dependent outflow. The oscillation is hypothetically connected to large-scale atmospheric circulation patterns originating in the mid-latitude North Pacific that support the flux of moisture into the region from the Gulf of Mexico. Recent data indicate an apparent change in the historical oscillation characterized by a ~12y downward trend beginning in 1998. Record low water levels region-wide may mark the onset of a new hydroclimatic regime.

  4. NNDSS - Table III. Tuberculosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table III. Tuberculosis - 2018.This Table includes total number of cases reported in the United States, by region and by states, in accordance with the...

  5. Pension Insurance Data Tables

    Data.gov (United States)

    Pension Benefit Guaranty Corporation — Find out about retirement trends in PBGC's data tables. The tables include statistics on the people and pensions that PBGC protects, including how many Americans are...

  6. NNDSS - Table IV. Tuberculosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table IV. Tuberculosis - 2016.This Table includes total number of cases reported in the United States, by region and by states, in accordance with the...

  7. NNDSS - Table IV. Tuberculosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table IV. Tuberculosis - 2014.This Table includes total number of cases reported in the United States, by region and by states, in accordance with the...

  8. NNDSS - Table II. Vibriosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Vibriosis - 2017. In this Table, provisional cases of selected notifiable diseases (≥1,000 cases reported during the preceding year), and selected...

  9. NNDSS - Table III. Tuberculosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table III. Tuberculosis - 2017.This Table includes total number of cases reported in the United States, by region and by states, in accordance with the...

  10. NNDSS - Table IV. Tuberculosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table IV. Tuberculosis - 2015.This Table includes total number of cases reported in the United States, by region and by states, in accordance with the...

  11. NNDSS - Table II. Vibriosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Vibriosis - 2018. In this Table, provisional cases of selected notifiable diseases (≥1,000 cases reported during the preceding year), and selected...

  12. Tabled Execution in Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Willcock, J J; Lumsdaine, A; Quinlan, D J

    2008-08-19

    Tabled execution is a generalization of memorization developed by the logic programming community. It not only saves results from tabled predicates, but also stores the set of currently active calls to them; tabled execution can thus provide meaningful semantics for programs that seemingly contain infinite recursions with the same arguments. In logic programming, tabled execution is used for many purposes, both for improving the efficiency of programs, and making tasks simpler and more direct to express than with normal logic programs. However, tabled execution is only infrequently applied in mainstream functional languages such as Scheme. We demonstrate an elegant implementation of tabled execution in Scheme, using a mix of continuation-passing style and mutable data. We also show the use of tabled execution in Scheme for a problem in formal language and automata theory, demonstrating that tabled execution can be a valuable tool for Scheme users.

  13. Filling the gap: using non-invasive geophysical methods to monitor the processes leading to enhanced carbon turnover induced by periodic water table fluctuations

    Science.gov (United States)

    Mellage, A.; Pronk, G.; Atekwana, E. A.; Furman, A.; Rezanezhad, F.; Van Cappellen, P.

    2017-12-01

    Subsurface transition environments such as the capillary fringe are characterized by steep gradients in redox conditions. Spatial and temporal variations in electron acceptor and donor availability - driven by hydrological changes - may enhance carbon turnover, in some cases resulting in pulses of CO2-respiration. Filling the mechanistic knowledge gap between the hydrological driver and its biogeochemical effects hinges on our ability to monitor microbial activity and key geochemical markers at a high spatial and temporal resolution. However, direct access to subsurface biogeochemical processes is logistically difficult, invasive and usually expensive. In-line, non-invasive geophysical techniques - Spectral Induced Polarization (SIP) and Electrodic Potential (EP), specifically - offer a comparatively inexpensive alternative and can provide data with high spatial and temporal resolution. The challenge lies in linking electrical responses to specific changes in biogeochemical processes. We conducted SIP and EP measurements on a soil column experiment where an artificial soil mixture was subjected to monthly drainage and imbibition cycles. SIP responses showed a clear dependence on redox zonation and microbial abundance. Temporally variable responses exhibited no direct moisture dependence suggesting that the measured responses recorded changes in microbial activity and coincided with the depth interval over which enhanced carbon turnover was observed. EP measurements detected the onset of sulfate mineralization and mapped its depth zonation. SIP and EP signals thus detected enhanced microbial activity within the water table fluctuation zone as well as the timing of the development of specific reactive processes. These findings can be used to relate measured electrical signals to specific reaction pathways and help inform reactive transport models, increasing their predictive capabilities.

  14. AcuTable

    DEFF Research Database (Denmark)

    Dibbern, Simon; Rasmussen, Kasper Vestergaard; Ortiz-Arroyo, Daniel

    2017-01-01

    In this paper we describe AcuTable, a new tangible user interface. AcuTable is a shapeable surface that employs capacitive touch sensors. The goal of AcuTable was to enable the exploration of the capabilities of such haptic interface and its applications. We describe its design and implementation...

  15. Table Tennis Club

    CERN Multimedia

    Table Tennis Club

    2013-01-01

    Apparently table tennis plays an important role in physics, not so much because physicists are interested in the theory of table tennis ball scattering, but probably because it provides useful breaks from their deep intellectual occupation. It seems that many of the greatest physicists took table tennis very seriously. For instance, Heisenberg could not even bear to lose a game of table tennis, Otto Frisch played a lot of table tennis, and had a table set up in his library, and Niels Bohr apparently beat everybody at table tennis. Therefore, as the CERN Table Tennis Club advertises on a poster for the next CERN Table Tennis Tournament: “if you want to be a great physicist, perhaps you should play table tennis”. Outdoor table at restaurant n° 1 For this reason, and also as part of the campaign launched by the CERN medical service “Move! & Eat better”, to encourage everyone at CERN to take regular exercise, the CERN Table Tennis Club, with the supp...

  16. Periodic Table of Students.

    Science.gov (United States)

    Johnson, Mike

    1998-01-01

    Presents an exercise in which an eighth-grade science teacher decorated the classroom with a periodic table of students. Student photographs were arranged according to similarities into vertical columns. Students were each assigned an atomic number according to their placement in the table. The table is then used to teach students about…

  17. Carbon dioxide flux and net primary production of a boreal treed bog: Responses to warming and water-table-lowering simulations of climate change

    Science.gov (United States)

    Munir, T. M.; Perkins, M.; Kaing, E.; Strack, M.

    2015-02-01

    Midlatitude treed bogs represent significant carbon (C) stocks and are highly sensitive to global climate change. In a dry continental treed bog, we compared three sites: control, recent (1-3 years; experimental) and older drained (10-13 years), with water levels at 38, 74 and 120 cm below the surface, respectively. At each site we measured carbon dioxide (CO2) fluxes and estimated tree root respiration (Rr; across hummock-hollow microtopography of the forest floor) and net primary production (NPP) of trees during the growing seasons (May to October) of 2011-2013. The CO2-C balance was calculated by adding the net CO2 exchange of the forest floor (NEff-Rr) to the NPP of the trees. From cooler and wetter 2011 to the driest and the warmest 2013, the control site was a CO2-C sink of 92, 70 and 76 g m-2, the experimental site was a CO2-C source of 14, 57 and 135 g m-2, and the drained site was a progressively smaller source of 26, 23 and 13 g CO2-C m-2. The short-term drainage at the experimental site resulted in small changes in vegetation coverage and large net CO2 emissions at the microforms. In contrast, the longer-term drainage and deeper water level at the drained site resulted in the replacement of mosses with vascular plants (shrubs) on the hummocks and lichen in the hollows leading to the highest CO2 uptake at the drained hummocks and significant losses in the hollows. The tree NPP (including above- and below-ground growth and litter fall) in 2011 and 2012 was significantly higher at the drained site (92 and 83 g C m-2) than at the experimental (58 and 55 g C m-2) and control (52 and 46 g C m-2) sites. We also quantified the impact of climatic warming at all water table treatments by equipping additional plots with open-top chambers (OTCs) that caused a passive warming on average of ~ 1 °C and differential air warming of ~ 6 °C at midday full sun over the study years. Warming significantly enhanced shrub growth and the CO2 sink function of the drained

  18. Oscillators - a simple introduction

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2013-01-01

    Oscillators are kernel components of electrical and electronic circuits. Discussion of history, mechanisms and design based on Barkhausens observation. Discussion of a Wien Bridge oscillator based on the question: Why does this circuit oscillate ?......Oscillators are kernel components of electrical and electronic circuits. Discussion of history, mechanisms and design based on Barkhausens observation. Discussion of a Wien Bridge oscillator based on the question: Why does this circuit oscillate ?...

  19. Oscillators and Eigenvalues

    DEFF Research Database (Denmark)

    Lindberg, Erik

    1997-01-01

    In order to obtain insight in the nature of nonlinear oscillators the eigenvalues of the linearized Jacobian of the differential equations describing the oscillator are found and displayed as functions of time. A number of oscillators are studied including Dewey's oscillator (piecewise linear wit...... with negative resistance), Kennedy's Colpitts-oscillator (with and without chaos) and a new 4'th order oscillator with hyper-chaos....

  20. Physical model of lean suppression pressure oscillation phenomena: steam condensation in the light water reactor pressure suppression system (PSS)

    International Nuclear Information System (INIS)

    McCauley, E.W.; Holman, G.S.; Aust, E.; Schwan, H.; Vollbrandt, J.

    1980-01-01

    Using the results of large scale multivent tests conducted by GKSS, a physical model of chugging is developed. The unique combination of accurate digital data and cinematic data has provided the derivation of a detailed, quantified correlation between the dynamic physical variables and the associated two-phase thermo-hydraulic phenomena occurring during lean suppression (chugging) phases of the loss-of-coolant accident in a boiling water reactor pressure suppression system

  1. A high-resolution record of Holocene millennial-scale oscillations of surface water, foraminiferal paleoecology and sediment redox chemistry in the SE Brazilian margin

    Science.gov (United States)

    Dias, B. B.; Barbosa, C. F.; Albuquerque, A. L.; Piotrowski, A. M.

    2014-12-01

    Holocene millennial-scale oscillations and Bond Events (Bond et al. 1997) are well reported in the North Atlantic as consequence of fresh water input and weaking of the Atlantic Meridional Overturning Circulation (AMOC). It has been hypothesized that the effect of weaking of AMOC would lead to warming in the South Atlantic due to "heat piracy", causing surface waters to warm and a reorganization of surface circulation. There are few reconstructions of AMOC strength in the South Atlantic, and none with a high resolution Holocene record of changes of productivity and the biological pump. We reconstruct past changes in the surface water mass hydrography, productivity, and sediment redox changes in high-resolution in the core KCF10-01B, located 128 mbsl water depth off Cabo Frio, Brazil, a location where upwelling is strongly linked to surface ocean hydrography. We use Benthic Foraminiferal Accumulation Rate (BFAR) to reconstruct productivity, which reveals a 1.3kyr cyclicity during the mid- and late-Holocene. The geochemistry of trace and rare earth elements on foraminiferal Fe-Mn oxide coatings show changes in redox-sensitive elements indicating that during periods of high productivity there were more reducing conditions in sediment porewaters, producing a Ce anomaly and reduction and re-precipitation of Mn oxides. Bond events 1-7 were identified by a productivity increase along with reducing sediment conditions which was likely caused by Brazil Current displacement offshore allowing upwelling of the nutritive bottom water South Atlantic Central Waters (SACW) to the euphotic zone and a stronger local biological pump. In a global context, correlation with other records show that this occurred during weakened AMOC and southward displacement of the ITCZ. We conclude that Bond climatic events and millennial-scale variability of AMOC caused sea surface hydrographic changes off the Brazilian Margin leading to biological and geochemical changes recorded in coastal records

  2. Mortality table construction

    Science.gov (United States)

    Sutawanir

    2015-12-01

    Mortality tables play important role in actuarial studies such as life annuities, premium determination, premium reserve, valuation pension plan, pension funding. Some known mortality tables are CSO mortality table, Indonesian Mortality Table, Bowers mortality table, Japan Mortality table. For actuary applications some tables are constructed with different environment such as single decrement, double decrement, and multiple decrement. There exist two approaches in mortality table construction : mathematics approach and statistical approach. Distribution model and estimation theory are the statistical concepts that are used in mortality table construction. This article aims to discuss the statistical approach in mortality table construction. The distributional assumptions are uniform death distribution (UDD) and constant force (exponential). Moment estimation and maximum likelihood are used to estimate the mortality parameter. Moment estimation methods are easier to manipulate compared to maximum likelihood estimation (mle). However, the complete mortality data are not used in moment estimation method. Maximum likelihood exploited all available information in mortality estimation. Some mle equations are complicated and solved using numerical methods. The article focus on single decrement estimation using moment and maximum likelihood estimation. Some extension to double decrement will introduced. Simple dataset will be used to illustrated the mortality estimation, and mortality table.

  3. CERN Table Tennis Club

    CERN Multimedia

    CERN Table Tennis Club

    2014-01-01

    CERN Table Tennis Club Announcing CERN 60th Anniversary Table Tennis Tournament to take place at CERN, from July 1 to July 15, 2014   The CERN Table Tennis Club, reborn in 2008, is encouraging people at CERN to take more regular exercise. This is why the Club, thanks to the strong support of the CERN Staff Association, installed last season a first outdoor table on the terrace of restaurant # 1, and will install another one this season on the terrace of Restaurant # 2. Table tennis provides both physical exercise and friendly social interactions. The CERN Table Tennis club is happy to use the unique opportunity of the 60th CERN anniversary to promote table tennis at CERN, as it is a game that everybody can easily play, regardless of level. Table tennis is particularly well suited for CERN, as many great physicists play table tennis, as you might already know: “Heisenberg could not even bear to lose a game of table tennis”; “Otto Frisch played a lot of table tennis;...

  4. A long baseline RICH with a 27-kiloton water target and radiator for detection of neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Ypsilantis, T.; Seguinot, J.; Zichichi, A.

    1997-01-01

    A 27 kt water volume is investigated as a target for a long baseline neutrino beam from CERN to Gran Sasso. Charged secondaries from the neutrino interactions produce Cherenkov photons in water which are imaged as rings by a spherical mirror. The photon detector elements are 14 400 photomultipliers (PM`s) of 127 mm diameter or 3600 HPD`s of 250 mm diameter with single photon sensitivity. A coincidence signal of about 300 pixel elements in time with the SPS beam starts readout in bins of 1 ns over a period of 128 ns. Momentum, direction, and velocity of hadrons and mucons are determined from the width, center, and radius of the rings, respectively. Momentum is measured if multiple scattering dominates the ring width, as is the case for most of the particles of interest. Momentum, direction, and velocity of hadrons and muons are determined from the width, center, and radius of the rings, respectively. Momentum is measured if multiple scattering dominates the ring width, as is the case for most of the particles of interest. Momentum resolutions of 1-10%, mass resolutions of 5-50 MeV, and direction resolutions of < 1 mrad are achievable. Thresholds in water for muons, pions, kaons, and protons are 0.12, 0.16, 0.55, and 1.05 GeV/c, respectively. Electrons and gammas can be measured with energy resolution {sigma}{sub E}/E{approx}8.5%/{radical}E(GeV) and with direction resolution {approx} 1 mrad. The detector can be sited either inside a Gran Sasso tunnel or above ground because it is directional and the SPS beam is pulsed; thus the rejection of cosmic ray background is excellent.

  5. A long baseline RICH with a 27-kiloton water target and radiator for detection of neutrino oscillations

    International Nuclear Information System (INIS)

    Ypsilantis, T.; Seguinot, J.; Zichichi, A.

    1997-01-01

    A 27 kt water volume is investigated as a target for a long baseline neutrino beam from CERN to Gran Sasso. Charged secondaries from the neutrino interactions produce Cherenkov photons in water which are imaged as rings by a spherical mirror. The photon detector elements are 14 400 photomultipliers (PM's) of 127 mm diameter or 3600 HPD's of 250 mm diameter with single photon sensitivity. A coincidence signal of about 300 pixel elements in time with the SPS beam starts readout in bins of 1 ns over a period of 128 ns. Momentum, direction, and velocity of hadrons and mucons are determined from the width, center, and radius of the rings, respectively. Momentum is measured if multiple scattering dominates the ring width, as is the case for most of the particles of interest. Momentum, direction, and velocity of hadrons and muons are determined from the width, center, and radius of the rings, respectively. Momentum is measured if multiple scattering dominates the ring width, as is the case for most of the particles of interest. Momentum resolutions of 1-10%, mass resolutions of 5-50 MeV, and direction resolutions of E /E∼8.5%/√E(GeV) and with direction resolution ∼ 1 mrad. The detector can be sited either inside a Gran Sasso tunnel or above ground because it is directional and the SPS beam is pulsed; thus the rejection of cosmic ray background is excellent

  6. Control Strategy of an Impulse Turbine for an Oscillating Water Column-Wave Energy Converter in Time-Domain Using Lyapunov Stability Method

    Directory of Open Access Journals (Sweden)

    Seung Kwan Song

    2016-10-01

    Full Text Available We present two control strategies for an oscillating water column-wave energy converter (OWC-WEC in the time domain. We consider a fixed OWC-WEC on the open sea with an impulse turbine module. This system mainly consists of a chamber, turbine and electric generator. For the time domain analysis, all of the conversion stages considering mutualities among them should be analyzed based on the Newtonian mechanics. According to the analysis of Newtonian mechanics, the hydrodynamics of wave energy absorption in the chamber and the turbine aerodynamic performance are directly coupled and share the internal air pressure term via the incompressible air assumption. The turbine aerodynamics and the dynamics of the electric generator are connected by torque load through the rotor shaft, which depends on an electric terminal load that acts as a control input. The proposed control strategies are an instant maximum turbine efficiency tracking control and a constant angular velocity of the turbine rotor control methods. Both are derived by Lyapunov stability analysis. Numerical simulations are carried out under irregular waves with various heights and periods in the time domain, and the results with the controllers are analyzed. We then compare these results with simulations carried out in the absence of the control strategy in order to prove the performance of the controllers.

  7. Development of NUFREQ-N, an analytical model for the stability analysis of nuclear coupled density-wave oscillations in boiling water nuclear reactors

    International Nuclear Information System (INIS)

    Park, G.C.

    1983-01-01

    A state-of-the-art one-dimensional thermal-hydraulic model has been developed to be used for the linear analysis of nuclear-coupled density-wave oscillations in a boiling water nuclear reactor (BWR). The model accounts for phasic slip, distributed spacers, subcooled boiling, space/time-dependent power distributions and distributed heated wall dynamics. In addition to a parallel channel stability analysis, a detailed model was derived for the BWR loop analysis of both the natural and forced circulation modes of operation. In its final form, this model constitutes a multi-input, multi-output (MIMO) linear system, which features a general nodal neutron kinetics model. Kinetics parameters for use in the kinetics model have been obtained by utilizing self-consistent nodal data and power distributions. The stability characteristics of a typical BWR/4 has been investigated with the Nyquist criterion. The computer implementation of this mode, NUFREQ-N, was used for the parametric study of a typical BWR/4 and comparison were made with existing in-core and out-of-core data. Also, NUFREQ-N was used to analyze the expected stability characteristics of a typical BWR/4. The parametric results revealed important factors influencing BWR stability margin. It was found that NUFREQ-N generally agreed well with out-of-core data. This was especially true for the predicted power-to-flow transfer function, which is the most important transfer function in thermal-hydraulic stability analysis

  8. TABLE TENNIS CLUB

    CERN Document Server

    TABLE TENNIS CLUB

    2010-01-01

    2010 CERN Table Tennis Tournament The CERN Table Tennis Club organizes its traditional CERN Table Tennis Tournament, at the Meyrin club, 2 rue de livron, in Meyrin, Saturday August 21st, in the afternoon. The tournament is open to all CERN staff, users, visitors and families, including of course summer students. See below for details. In order to register, simply send an E-mail to Jean-Pierre Revol (jean-pierre.revol@cern.ch). You can also download the registration form from the Club Web page (http://www.cern.ch/tabletennis), and send it via internal mail. Photo taken on August 22, 2009 showing some of the participants in the 2nd CERN Table Tennis tournament. INFORMATION ON CERN TABLE TENNIS CLUB CERN used to have a tradition of table tennis activities at CERN. For some reason, at the beginning of the 1980’s, the CERN Table Tennis club merged with the Meyrin Table Tennis club, a member of the Association Genevoise de Tennis de Table (AGTT). Therefore, if you want to practice table tennis, you...

  9. Experimental observation of shear thickening oscillation

    DEFF Research Database (Denmark)

    Nagahiro, Shin-ichiro; Nakanishi, Hiizu; Mitarai, Namiko

    2013-01-01

    We report experimental observations of the shear thickening oscillation, i.e. the spontaneous macroscopic oscillation in the shear flow of severe shear thickening fluid. Using a density-matched starch-water mixture, in the cylindrical shear flow of a few centimeters flow width, we observed...

  10. Standard Reference Tables -

    Data.gov (United States)

    Department of Transportation — The Standard Reference Tables (SRT) provide consistent reference data for the various applications that support Flight Standards Service (AFS) business processes and...

  11. Evaluation of a computer model to simulate water table response to subirrigation Avaliação de um modelo computacional para simular a resposta do lençol freático à subirrigação

    Directory of Open Access Journals (Sweden)

    Jadir Aparecido Rosa

    2002-12-01

    Full Text Available The objective of this work was to evaluate the water flow computer model, WATABLE, using experimental field observations on water table management plots from a site located near Hastings, FL, USA. The experimental field had scale drainage systems with provisions for subirrigation with buried microirrigation and conventional seepage irrigation systems. Potato (Solanum tuberosum L. growing seasons from years 1996 and 1997 were used to simulate the hydrology of the area. Water table levels, precipitation, irrigation and runoff volumes were continuously monitored. The model simulated the water movement from a buried microirrigation line source and the response of the water table to irrigation, precipitation, evapotranspiration, and deep percolation. The model was calibrated and verified by comparing simulated results with experimental field observations. The model performed very well in simulating seasonal runoff, irrigation volumes, and water table levels during crop growth. The two-dimensional model can be used to investigate different irrigation strategies involving water table management control. Applications of the model include optimization of the water table depth for each growth stage, and duration, frequency, and rate of irrigation.O objetivo deste trabalho foi avaliar o modelo computacional WATABLE usando-se dados de campo obtidos em uma área experimental em manejo de lençol freático, localizada em Hastings, FL, EUA. Na área experimental, estavam instalados um sistema de drenagem e sistemas de irrigação por subsuperfície com irrigação localizada e por canais. Ciclos de cultivo de batata (Solanum tuberosum L., nos anos de 1996 e 1997, foram usados para a simulação da hidrologia da área. Profundidades do lençol freático, chuvas, irrigação e escorrimento superficial foram monitorados constantemente. O modelo simulou o movimento da água a partir de uma linha de irrigação localizada enterrada, e a resposta do nível do len

  12. High temporal resolution modeling of the impact of rain, tides, and sea level rise on water table flooding in the Arch Creek basin, Miami-Dade County Florida USA.

    Science.gov (United States)

    Sukop, Michael C; Rogers, Martina; Guannel, Greg; Infanti, Johnna M; Hagemann, Katherine

    2018-03-01

    Modeling of groundwater levels in a portion of the low-lying coastal Arch Creek basin in northern Miami-Dade County in Southeast Florida USA, which is subject to repetitive flooding, reveals that rain-induced short-term water table rises can be viewed as a primary driver of flooding events under current conditions. Areas below 0.9m North American Vertical Datum (NAVD) elevation are particularly vulnerable and areas below 1.5m NAVD are vulnerable to exceptionally large rainfall events. Long-term water table rise is evident in the groundwater data, and the rate appears to be consistent with local rates of sea level rise. Linear extrapolation of long-term observed groundwater levels to 2060 suggest roughly a doubling of the number of days when groundwater levels exceed 0.9m NAVD and a threefold increase in the number of days when levels exceed 1.5m NAVD. Projected sea level rise of 0.61m by 2060 together with increased rainfall lead to a model prediction of frequent groundwater-related flooding in areas1.5m NAVD and widespread flooding of the area in the past. Tidal fluctuations in the water table are predicted to be more pronounced within 600m of a tidally influenced water control structure that is hydrodynamically connected to Biscayne Bay. The inland influence of tidal fluctuations appears to increase with increased sea level, but the principal driver of high groundwater levels under the 2060 scenario conditions remains groundwater recharge due to rainfall events. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. The Living Periodic Table

    Science.gov (United States)

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  14. The effect of spherical hub-nose position on pressure drop in an oscillating water column system for wave energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Z.; Ahmad, N.; Ghazilla, R.A.R.; Yap, H.J.; Ya, T.Y.T.; Passarella, R.; Hasanuddin, I.; Yunus, M. [Malaya Univ. (Malaysia). Centre for Product Design and Manufacturing; Sugiyono [Malaya Univ., (Malaysia). Centre for Product Design and Manufacturing; Gadjah Mada Univ. (Indonesia). Dept. of Mechanical and Industrial Engineering

    2009-07-01

    The use of renewable energy sources as an alternative to conventional fuels was discussed with particular reference to ocean wave energy and its potential to contribute to the energy requirements of coastal nations. Ocean wave energy has been harnessed and converted into electricity using processes and technologies that are environmentally sound. The oscillating water column (OWC) system is considered to be among the most promising technology for harnessing wave energy. This paper presented the results of a study that investigated the pressure drop in an OWC system and the effect of spherical hub-nose position in an annular duct. Computational fluid dynamics (CFD) analysis was used under steady flow conditions for several hub-nose positions to determine the characteristic of pressure drop. The study showed that the hub-nose position influenced the pressure drop in the OWC system. The highest value of the pressure drop in this study occurred when the hub-nose was at the position of 0.0 m relative to the end of the converging cone. The pressure drop decreased when the hub-nose position moved away from the end of converging cone. The lowest value occurred at the position of -0.5 m. It was concluded that despite the numerically small change in pressure drop, this phenomenon should be considered in the design process of the OWC system because of the operational condition of the system at low-pressure pneumatic power. The pressure drop actually reduces the amount of energy that will be converted by the air turbine. 9 refs., 2 tabs., 6 figs.

  15. Qualification of the calculational methods of the fluence in the pressurised water reactors. Improvement of the cross sections treatment by the probability table method

    International Nuclear Information System (INIS)

    Zheng, S.H.

    1994-01-01

    It is indispensable to know the fluence on the nuclear reactor pressure vessel. The cross sections and their treatment have an important rule to this problem. In this study, two ''benchmarks'' have been interpreted by the Monte Carlo transport program TRIPOLI to qualify the calculational method and the cross sections used in the calculations. For the treatment of the cross sections, the multigroup method is usually used but it exists some problems such as the difficulty to choose the weighting function and the necessity of a great number of energy to represent well the cross section's fluctuation. In this thesis, we propose a new method called ''Probability Table Method'' to treat the neutron cross sections. For the qualification, a program of the simulation of neutron transport by the Monte Carlo method in one dimension has been written; the comparison of multigroup's results and probability table's results shows the advantages of this new method. The probability table has also been introduced in the TRIPOLI program; the calculational results of the iron deep penetration benchmark has been improved by comparing with the experimental results. So it is interest to use this new method in the shielding and neutronic calculation. (author). 42 refs., 109 figs., 36 tabs

  16. Oscillating heat pipes

    CERN Document Server

    Ma, Hongbin

    2015-01-01

    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  17. Elementary Statistics Tables

    CERN Document Server

    Neave, Henry R

    2012-01-01

    This book, designed for students taking a basic introductory course in statistical analysis, is far more than just a book of tables. Each table is accompanied by a careful but concise explanation and useful worked examples. Requiring little mathematical background, Elementary Statistics Tables is thus not just a reference book but a positive and user-friendly teaching and learning aid. The new edition contains a new and comprehensive "teach-yourself" section on a simple but powerful approach, now well-known in parts of industry but less so in academia, to analysing and interpreting process dat

  18. Automatic Oscillating Turret.

    Science.gov (United States)

    1981-03-01

    Final Report: February 1978 ZAUTOMATIC OSCILLATING TURRET SYSTEM September 1980 * 6. PERFORMING 01G. REPORT NUMBER .J7. AUTHOR(S) S. CONTRACT OR GRANT...o....e.... *24 APPENDIX P-4 OSCILLATING BUMPER TURRET ...................... 25 A. DESCRIPTION 1. Turret Controls ...Other criteria requirements were: 1. Turret controls inside cab. 2. Automatic oscillation with fixed elevation to range from 20* below the horizontal to

  19. Neutrino oscillations in matter

    International Nuclear Information System (INIS)

    Mikheyev, S.P.; Smirnov, A.Yu.

    1986-01-01

    In this paper we describe united formalism of ν-oscillations for different regimes, which is immediate generalization of vacuum oscillations theory. Adequate graphical representation of this formalism is given. We summarize main properties of ν-oscillations for different density distributions. (orig./BBOE)

  20. The colpitts oscillator family

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamasevicius, A.

    A tutorial study of the Colpitts oscillator family defined as all oscillators based on a nonlinear amplifier and a three- terminal linear resonance circuit with one coil and two capacitors. The original patents are investigated. The eigenvalues of the linearized Jacobian for oscillators based...

  1. Empirical yield tables for Michigan.

    Science.gov (United States)

    Jerold T. Hahn; Joan M. Stelman

    1984-01-01

    Describes the tables derived from the 1980 Forest Survey of Michigan and presents ways the tables can be used. These tables are broken down according to Michigan's four Forest Survey Units, 14 forest types, and 5 site-index classes.

  2. Empirical yield tables for Wisconsin.

    Science.gov (United States)

    Jerold T. Hahn; Joan M. Stelman

    1989-01-01

    Describes the tables derived from the 1983 Forest Survey of Wisconsin and presents ways the tables can be used. These tables are broken down according to Wisconsin`s five Forest Survey Units and 14 forest types.

  3. Permit.LOA table

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This table includes the effective dates by vessel and permit number for each issued letter of authorization (LOA) by the Permit Office (APSD)

  4. VMS forms Output Tables

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These output tables contain parsed and format validated data from the various VMS forms that are sent from any given vessel, while at sea, from the VMS devices on...

  5. The Periodic Table CD.

    Science.gov (United States)

    Banks, Alton J.; Holmes, Jon L.

    1995-01-01

    Describes the characteristics of the digitized version of The Periodic Table Videodisc. Provides details about the organization of information and access to the data via Macintosh and Windows computers. (DDR)

  6. Setting the Periodic Table.

    Science.gov (United States)

    Saturnelli, Annette

    1985-01-01

    Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

  7. Body Mass Index Table

    Science.gov (United States)

    ... Families ( We Can! ) Health Professional Resources Body Mass Index Table 1 for BMI greater than 35, go ... Health Information Email Alerts Jobs and Careers Site Index About NHLBI National Institute of Health Department of ...

  8. Decision table languages and systems

    CERN Document Server

    Metzner, John R

    1977-01-01

    ACM Monograph Series: Decision Table Languages and Systems focuses on linguistic examination of decision tables and survey of the features of existing decision table languages and systems. The book first offers information on semiotics, programming language features, and generalization. Discussions focus on semantic broadening, outer language enrichments, generalization of syntax, limitations, implementation improvements, syntactic and semantic features, decision table syntax, semantics of decision table languages, and decision table programming languages. The text then elaborates on design im

  9. 27 CFR 30.66 - Table 6, showing respective volumes of alcohol and water and the specific gravity in both air and...

    Science.gov (United States)

    2010-04-01

    ... respective volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor... volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor. This... gallon of water in air by the specific gravity in air of the spirits—8.32823 by 0.88862—the product (7...

  10. Atmospheric neutrino oscillations for earth tomography

    International Nuclear Information System (INIS)

    Winter, Walter

    2016-01-01

    Modern proposed atmospheric neutrino oscillation experiments, such as PINGU in the Antarctic ice or ORCA in Mediterranean sea water, aim for precision measurements of the oscillation parameters including the ordering of the neutrino masses. They can, however, go far beyond that: Since neutrino oscillations are affected by the coherent forward scattering with matter, neutrinos can provide a new view on the interior of the earth. We show that the proposed atmospheric oscillation experiments can measure the lower mantle density of the earth with a precision at the level of a few percent, including the uncertainties of the oscillation parameters and correlations among different density layers. While the earth's core is, in principle, accessible by the angular resolution, new technology would be required to extract degeneracy-free information.

  11. The 2005 CHF look-up table

    International Nuclear Information System (INIS)

    Groeneveld, D.C.; Vasic, A.Z.; Leung, L.K.H.; Durmayaz, A.; Shan, J.Q.; Yang, J.; Cheng, S.C.

    2005-01-01

    Full text of publication follows: CHF Look-up tables have been used widely for the prediction of the Critical Heat Flux (CHF) The CHF look-up table is basically a normalized data bank. The first CHF look-up table was constructed by Doroshchuk et al. (1975), using a limited database of 5 000 data points. This table, and all subsequent tables, contain normalized CHF values for a vertical 8 mm water-cooled tube for various pressures, mass fluxes and qualities. The CHF table development work has since been in progress at various institutions (e.g. CENG-Grenoble, University of Ottawa (UO), Ottawa, IPPE, Obninsk, and AECL, Chalk River) using an ever increasing data base. The 1995 CHF look-up table employs a data base containing about 30 000 CHF points and provides CHF values for an 8 mm ID, water-cooled tube, for 19 pressures, 20 mass fluxes, and 23 qualities. covering the full range of conditions of practical interest. The 2005 CHF LUT is an update to the 1995 LUT and addresses several concerns raised in the literature. The major improvements made are: - enhancement of the quality of the data base of the CHF look-up table (identify outliers, improve screening procedures); - increase in the data base by adding recently obtained data; - employment of greater subdivision of the look-up table by using smaller intervals in the independent parameters (pressure, mass flux and quality) at conditions where the variation in CHF is significant; - improvement of the smoothness of the CHF look-up table. This was done by the use of logarithmic functions for CHF, using optimum Spline functions etc. A discussion of the impact of these changes on the prediction accuracy and table smoothness is presented. It will be shown that the 2005 CHF look-up table is characterized by a significant improvement in accuracy and smoothness. [1] D. Groeneveld is the corresponding author. He is an Adjunct Professor at the University of Ottawa. (authors)

  12. Nature's Autonomous Oscillators

    Science.gov (United States)

    Mayr, H. G.; Yee, J.-H.; Mayr, M.; Schnetzler, R.

    2012-01-01

    Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology.

  13. A memristor-based third-order oscillator: beyond oscillation

    KAUST Repository

    Talukdar, Abdul Hafiz Ibne

    2012-10-06

    This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

  14. A memristor-based third-order oscillator: beyond oscillation

    KAUST Repository

    Talukdar, Abdul Hafiz Ibne; Radwan, Ahmed G.; Salama, Khaled N.

    2012-01-01

    This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

  15. Reading the Water Table: The Interaction between Literacy Practices and Groundwater Management Training in Preparing Farmers for Climate Change in South India

    Science.gov (United States)

    Chavva, Konda Reddy; Smith, Cristine A.

    2012-01-01

    This article focuses on farmers' use of literacy for individual decision-making on crop-water management and crop choices and investigates how farmer participants perceive the usefulness of Farmer Water School (FWS) training. It draws upon a study conducted with farmers of Kurnool district of Andhra Pradesh, India. This study has demonstrated that…

  16. Empirical yield tables for Minnesota.

    Science.gov (United States)

    Jerold T. Hahn; Gerhard K. Raile

    1982-01-01

    Describes the tables derived from the 1977 Forest Survey of Minnesota and presents examples of how the tables can be used. These tables are broken down according to Minnesota's four Forest Survey Units, 14 forest types, and 5 site index classes. Presents 210 of the 350 possible tables that contained sufficient data to justify publication.

  17. X-ray table

    International Nuclear Information System (INIS)

    Craig, J.R.; Otto, G.W.

    1980-01-01

    An X-ray radiographic or fluoroscopic table is described which includes a film holder with a frame attached to a cable running over end pulleys for positioning the holder longitudinally as desired under the table top. The holder has a front opening to receive a cassette-supporting tray which can be slid out on tracks to change the cassette. A reed switch on the frame is opened by a permanent magnet on the tray only when the tray is half-way out. When the switch is closed, an electromagnet locks the pulley and the holder in place. The holder is thus automatically locked in place not only during exposure (tray in) but when the tray is out for changing the cassette. To re-position the holder, the operator pulls the tray half-out and, using the tray itself, pushes the holder along the table, the holder being counterbalanced by a weight. (author)

  18. Table Tennis Club

    CERN Multimedia

    Table Tennis Club

    2012-01-01

    The CERN Table Tennis club and the Meyrin CTT are organizing two Table Tennis workshops from 2 to 6 July and from 20 to 24 August 2012 inclusive in Meyrin. A professional would be with your children from 14.00 pm to 18.00 pm: an instructor J + S category A. Training courses with specific themes, individual courses would be given depending on the level of the child’s game, “discoveries –table tennis games” courses and games with the robot. Other activities (stretching, relaxation). Afternoons (from 18 to 20 children): 40 CHF per workshop and per child. Evenings (from 18 to 20 adults): 60 CHF per workshop and per adult. For further information, please contact Mr. Monteil : Mobile: (+33) 06 61 31 70 47 E-mail: wilfried.monteil@free.fr.

  19. Periodic table of elements

    International Nuclear Information System (INIS)

    Fluck, E.; Heumann, K.G.

    1985-01-01

    Following a recommendation by the International Union for Pure and Applied Chemistry (IUPAC), the groups of the periodic table shall be numbered from 1 to 18, instead of I to VIII as before. The recommendations has been approved of by the Committee on Nomenclature of the American Chemical Society. The new system abandons the distinction between main groups (a) and auxiliary groups (b), which in the past frequently has been the reason for misunderstandings between European and American chemists, due to different handling. The publishing house VCH Verlagsgesellschaft recently produced a new periodic table that shows the old and the new numbering system together at a glance, so that chemists will have time to get familiar with the new system. In addition the new periodic table represents an extensive data compilation arranged by elements. The front page lists the chemical properties of elements, the back page their physical properties. (orig./EF) [de

  20. Dosimetric Effects Of Different Treatment Tables During Radiotherapy

    International Nuclear Information System (INIS)

    Murkovic, M.; Grego, T.; Bibic, J.

    2015-01-01

    The aim of our study was to measure the effect of mega-voltage photon beam attenuation when treating patients through carbon fibre treatment table with and without the carbon laminate base plate on it. We also examined the ability of XiO treatment planning system in modelling this effect. Direct attenuation measurements were made for two treatment tables, Siemens TxT 550 treatment table with TT-A table top and Elekta Precise table with iBEAM evo table top. On both treatment tables we used Orfit Base Plate (32301). Measurements were taken for two photon energies (6 MV and 18 MV), at two different field sizes (5 x 5 cm 2 and 10 x 10 cm 2 ) and different gantry angles in 50 intervals using stationary water phantom and Farmer type ionization chamber. These values were compared to values calculated in XiO. In order to account for the effect of table and base plate during treatment planning in XiO, customized table and base plate templates were develop in Focal planning system. To construct these customized templates, table and base plate contours as well as respective relative electron density's to water were obtained on CT scanner. The largest attenuation effect was seen for oblique treatment angles using low energy and small field sizes, 6.6 percent for the Elekta table top and 8.4 percent for Siemens table top. In this paper we show that customized table and base plate templates introduced in the patient treatment plan can accurately model the attenuation due to their presence to within 0.3 percent. Since dose modifications due to such carbon fiber accessories can be significant, it can be concluded that introduction of customized table and base plate templates into TPS brings an important improvement to patient treatment planning, and should be included in dose calculations whenever possible. (author).

  1. Oscillations of disks

    CERN Document Server

    Kato, Shoji

    2016-01-01

    This book presents the current state of research on disk oscillation theory, focusing on relativistic disks and tidally deformed disks. Since the launch of the Rossi X-ray Timing Explorer (RXTE) in 1996, many high-frequency quasiperiodic oscillations (HFQPOs) have been observed in X-ray binaries. Subsequently, similar quasi-periodic oscillations have been found in such relativistic objects as microquasars, ultra-luminous X-ray sources, and galactic nuclei. One of the most promising explanations of their origin is based on oscillations in relativistic disks, and a new field called discoseismology is currently developing. After reviewing observational aspects, the book presents the basic characteristics of disk oscillations, especially focusing on those in relativistic disks. Relativistic disks are essentially different from Newtonian disks in terms of several basic characteristics of their disk oscillations, including the radial distributions of epicyclic frequencies. In order to understand the basic processes...

  2. Efeito de velocidades de rebaixamento do nível freático em diferentes períodos de desenvolvimento da cultura da alface Effect of water table drawdown velocities in different stages of lettuce crop

    Directory of Open Access Journals (Sweden)

    Rafael Mingoti

    2006-03-01

    Full Text Available Através deste trabalho objetivou-se determinar os efeitos do encharcamento do solo nas variáveis fenológicas e na produtividade da cultura da alface, identificar o estádio fenológico em que ocorre a maior diminuição da produtividade e obter uma relação entre a produtividade relativa da cultura e o índice diário de estresse. O delineamento experimental adotado foi inteiramente casualizado, arranjado em esquema fatorial [(3x4+1], com 3 repetições. Os tratamentos consistiram do período de inundação (12, 22 e 32 DAT, de velocidades de rebaixamento do nível freático (30 cm em 24, 48, 72 e 96 horas e uma testemunha, na qual não foi aplicado estresse por elevação do lençol freático. A alface apresentou-se como cultura sensível ao encharcamento; entretanto, não foi possível se definir um valor para o coeficiente de drenagem pois, mesmo com a maior velocidade de rebaixamento testada, ocorreu decréscimo de cerca de 50% da produção. Dentre os três períodos nos quais o estresse causado pela elevação do nível freático foi aplicado, o primeiro foi o que ocasionou maiores perdas. A produtividade das plantas de alface apresentou correlação linear negativa com o índice diário de estresse (IDS.The work had the objectives of determining the effect of water table drawdown velocities on the growth and yield of lettuce crop in a flooded soil, identifying the stage of the crop cycle with the highest reduction in the productivity and obtaining a relation between the crop relative productivity and the daily stress index. The statistical experimental design was completely randomized in factorial scheme [(3 x 4 + 1], with three replications. The water table was lowered at 3 stages of the crop cycle (12, 22 and 32 days after the transplanting, four drawdown velocities (30 cm during 24, 48, 72 and 96 h and a 13 treatment in which stress was not applied with the elevation of the water table. The lettuce presented as a sensible crop to

  3. Application of the new IAPWS Guideline on the fast and accurate calculation of steam and water properties with the Spline-Based Table Look-Up Method (SBTL) in RELAP-7

    Energy Technology Data Exchange (ETDEWEB)

    Kunick, Matthias; Kretzschmar, Hans-Joachim [Zittau/Goerlitz Univ. of Applied Sciences, Zittau (Germany). Dept. of Technical Thermodynamics; Berry, Ray A.; Martineau, Richard C. [Idaho National Laboratory, Idaho Falls, ID (United States). Nuclear Science and Technology; Gampe, Uwe [Dresden Univ. of Technology (Germany). Chair of Thermal Power Machinery and Plants

    2017-07-15

    The numerical simulation of thermalhydraulic processes in nuclear power plants requires very accurate and extremely fast algorithms for calculating the thermophysical properties of water and steam. In order to provide such algorithms, the International Association for the Properties of Water and Steam (IAPWS) has adopted the new ''IAPWS Guideline on the Fast Calculation of Steam and Water Properties with the Spline-Based Table Look-Up Method (SBTL)''. In this article, the SBTL method is applied to property functions of specific volume and specific internal energy (v,e) based on the scientific formulation IAPWS-95 and the latest IAPWS formulations for transport properties. From the newly generated SBTL functions, thermodynamic and transport properties as well as their derivatives and inverse functions are calculable in the fluid range of state for pressures up to 100 MPa and for temperatures up to 1273 K, including the metastable liquid and the metastable vapor regions. The SBTL functions reproduce the underlying formulations with an accuracy of 10-100 ppm and significantly reduced computing times. The SBTL method has been implemented into the nuclear reactor system safety analysis code RELAP-7 [2] to consider the real fluid behavior of water and steam in a novel 7-equation two-phase flow model.

  4. Code for the steam tables for pure water in visual basic 6.0.; Un codigo para las tablas de vapor para agua pura en visual basic 6.0

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Mahendra P. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2002-07-01

    The thermodynamic data of the water are of extreme importance in all of the branches of science and technology; the facilitate the understanding of the natural Earth processes. Nevertheless, for the electrical industry the water plays a very important role during the generation of electrical energy process. Different heat sources such as coal, oil, natural gas, nuclear fuel or the geothermal heat boil the water that forms the steam used to move the turbines. Consequently, the steam tables (the thermodynamic water data) are vital to model thermal and mass transference and physical-chemical processes during the generation of electrical energy. [Spanish] Los datos termodinamicos del agua son de suma importancia en todas las ramas de la ciencia y tecnologia, ellos facilitan el entendimiento de los procesos naturales de la Tierra. Sin embargo, para la industria electrica el agua juega un papel muy importante durante el proceso de generacion de energia electrica. Diferentes fuentes de calor tales como carbon, aceite, gas natural, combustible nuclear o el calor geotermico calientan el agua que forma el vapor utilizado para mover las turbinas. Luego entonces, las tablas de vapor (los datos termodinamicos de agua) son vitales para modelar transferencia termica y de masa y procesos fisico-quimico durante la generacion energia electrica.

  5. Oscillations in stellar atmospheres

    International Nuclear Information System (INIS)

    Costa, A.; Ringuelet, A.E.; Fontenla, J.M.

    1989-01-01

    Atmospheric excitation and propagation of oscillations are analyzed for typical pulsating stars. The linear, plane-parallel approach for the pulsating atmosphere gives a local description of the phenomenon. From the local analysis of oscillations, the minimum frequencies are obtained for radially propagating waves. The comparison of the minimum frequencies obtained for a variety of stellar types is in good agreement with the observed periods of the oscillations. The role of the atmosphere in the globar stellar pulsations is thus emphasized. 7 refs

  6. Changes in the water-table altitude of the unconfined aquifer, Wood River Valley aquifer system, south-central Idaho, October 2006 to October 2012.

    Data.gov (United States)

    Department of the Interior — Water levels in 93 wells completed in the Wood River Valley aquifer system were measured during October 22–24, 2012; these wells are part of a network established...

  7. Climate change : transportation table

    International Nuclear Information System (INIS)

    Ogilvie, K.

    1999-01-01

    The Kyoto Protocol sets greenhouse gas (GHG) reduction targets for the post-2000 period. If ratified, Canada will be committed to reduce emissions of GHGs by 6 per cent below 1990 levels during the period 2008-2012. A recommended national strategy is to establish 'issue tables' that will advise the Ministers of Energy and Environment on preferred options to reach the Kyoto target and to identify early actions that can be taken. The 'Transportation Table' which is the focus of this paper, is one of the 15 sectoral tables. The Transportation Table will identify by July 1999, specific measures to mitigate GHG emissions from Canada's transportation sector. Currently, GHG emissions from the transportation sector are predicted to be 27 per cent above 1990 levels by 2010. Fuel taxes, emissions trading, and research into improved vehicle technologies and automotive fuels are some of the recommended options which can help reduce emissions trading from the transportation sector. Studies are underway to deal with emissions from transport in two sub-groups, freight and passenger. 1 fig

  8. Statistical tables 2003

    International Nuclear Information System (INIS)

    2003-01-01

    The energy statistical table is a selection of statistical data for energies and countries from 1997 to 2002. It concerns the petroleum, the natural gas, the coal, the electric power, the production, the external market, the consumption per sector, the energy accounting 2002 and graphs on the long-dated forecasting. (A.L.B.)

  9. A Modern Periodic Table.

    Science.gov (United States)

    Herrenden-Harker, B. D.

    1997-01-01

    Presents a modern Periodic Table based on the electron distribution in the outermost shell and the order of filling of the sublevels within the shells. Enables a student to read off directly the electronic configuration of the element and the order in which filling occurs. (JRH)

  10. Conversion tables. Appendix I

    International Nuclear Information System (INIS)

    McKerrell, H.

    1975-01-01

    Tables are presented for the conversion of standard (5568 year half-life) C-14 dates to calendar years. The major part of the data converts C-14 dates to tree-ring years: additional data are given, based on the Egyptian historical curve. (U.K.)

  11. Analyzing and Improving the Water-Table Fluctuation Method of Estimating Groundwater Recharge: Field Considerations Patros, T.B. and Parkin, G.W., School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada

    Science.gov (United States)

    Patros, T.; Parkin, G. W.

    2012-12-01

    The focus of the project is on measuring and quantifying groundwater recharge (GWR) using the water-table fluctuation (WTF) method. This method requires measuring the change in water-table (WT) height (Δh) during recharge (R) events and volumetric soil specific yield water content (θsy), (&/or) perhaps more correctly volumetric soil fillable water content (θf). The rise in WT can also result from other non-precipitation-related WTF causes (e.g., Lisse effect, temperature variations, barometric, lateral flow, Reverse Wieringermeer effect, encapsulated air, pumping), which must be counted for. The measurement of the storativity (S) terms (θsy) and/or θf) is, indeed, not clear-cut and often they are taken as being constant with depth, time, WT movement (Drying-Wetting & Freezing-Thawing) history and heterogeneity. In fact, these two terms (θsy & θf) are controversial in their definition, thus in their use, in the literature and may either overestimate the R, when using θsy, or underestimate it, when using θf. To resolve some of these questions, a novel-automated method is under development, at the University of Guelph's Elora Research Station (ERS) and Arboretum, along with a novel multi-event time series model. The long-term expected outcomes and significance of this study are; 1. Establishing accuracy in defining and evaluating the θsy and θf and using them accordingly in estimating GWR with the WTF method in order to overcome some of the existing substantial gaps in our knowledge of groundwater (GW) storage variation. 2. Obtaining GWR measurements at the local scale on a year-round basis, which are currently scarce or even completely lacking for many regions of Ontario and thus would provide a valuable database for guiding development of any policy requiring GWR. 3. Using this database to calibrate and test estimates of the spatial and temporal variability in regional-scale (watershed scale) GWR from approximate statistical techniques or deterministic

  12. Stable isotope and noble gas constraints on the source and residence time of spring water from the Table Mountain Group Aquifer, Paarl, South Africa and implications for large scale abstraction

    Science.gov (United States)

    Miller, J. A.; Dunford, A. J.; Swana, K. A.; Palcsu, L.; Butler, M.; Clarke, C. E.

    2017-08-01

    Large scale groundwater abstraction is increasingly being used to support large urban centres especially in areas of low rainfall but presents particular challenges in the management and sustainability of the groundwater system. The Table Mountain Group (TMG) Aquifer is one of the largest and most important aquifer systems in South Africa and is currently being considered as an alternative source of potable water for the City of Cape Town, a metropolis of over four million people. The TMG aquifer is a fractured rock aquifer hosted primarily in super mature sandstones, quartzites and quartz arenites. The groundwater naturally emanates from numerous springs throughout the cape region. One set of springs were examined to assess the source and residence time of the spring water. Oxygen and hydrogen isotopes indicate that the spring water has not been subject to evaporation and in combination with Na/Cl ratios implies that recharge to the spring systems is via coastal precipitation. Although rainfall in the Cape is usually modelled on orographic rainfall, δ18O and δ2H values of some rainfall samples are strongly positive indicating a stratiform component as well. Comparing the spring water δ18O and δ2H values with that of local rainfall, indicates that the springs are likely derived from continuous bulk recharge over the immediate hinterland to the springs and not through large and/or heavy downpours. Noble gas concentrations, combined with tritium and radiocarbon activities indicate that the residence time of the TMG groundwater in this area is decadal in age with a probable maximum upper limit of ∼40 years. This residence time is probably a reflection of the slow flow rate through the fractured rock aquifer and hence indicates that the interconnectedness of the fractures is the most important factor controlling groundwater flow. The short residence time of the groundwater suggest that recharge to the springs and the Table Mountain Group Aquifer as a whole is

  13. The Oscillator Principle of Nature

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2012-01-01

    Oscillators are found on all levels in Nature. The general oscillator concept is defined and investigated. Oscillators may synchronize into fractal patterns. Apparently oscillators are the basic principle in Nature. The concepts of zero and infinite are discussed. Electronic manmade oscillators...

  14. Atomic structure calculation of energy levels and oscillator strengths in Ti ion, 2

    International Nuclear Information System (INIS)

    Ishii, Keishi

    1983-10-01

    Energy levels and oscillator strengths are calculated for 3s-3p and 3p-3d transition arrays in Ti X, isoelectronic to Al I. The energy levels are obtained by the Slater-Condon theory of atomic structure, including explicitly the strong configuration interactions. The results are presented both in numerical tables and in diagrams. In the tables, the observed data are included for comparison, where available. The calculated weighted oscillator strengths (gf-value) are also displayed in figures, where the weighted oscillator strengths are plotted as a function of wavelength. (author)

  15. On the Dirac oscillator

    International Nuclear Information System (INIS)

    Rodrigues, R. de Lima

    2007-01-01

    In the present work we obtain a new representation for the Dirac oscillator based on the Clifford algebra C 7. The symmetry breaking and the energy eigenvalues for our model of the Dirac oscillator are studied in the non-relativistic limit. (author)

  16. A Conspiracy of Oscillators

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    2008-01-01

    We discuss nonlinear mechanical systems containing several oscillators whose frequecies are all much higher than frequencies associated with the remaining degrees of freedom. In this situation a near constant of the motion, an adiabatic invariant, exists which is the sum of all the oscillator...... actions. The phenomenon is illustrated, and calculations of the small change of the adiabatic invariant is outlined....

  17. Synchronization of hyperchaotic oscillators

    DEFF Research Database (Denmark)

    Tamasevicius, A.; Cenys, A.; Mykolaitis, G.

    1997-01-01

    Synchronization of chaotic oscillators is believed to have promising applications in secure communications. Hyperchaotic systems with multiple positive Lyapunov exponents (LEs) have an advantage over common chaotic systems with only one positive LE. Three different types of hyperchaotic electronic...... oscillators are investigated demonstrating synchronization by means of only one properly selected variable....

  18. Regional analysis of groundwater phosphate concentrations under acidic sandy soils: Edaphic factors and water table strongly mediate the soil P-groundwater P relation.

    Science.gov (United States)

    Mabilde, Lisa; De Neve, Stefaan; Sleutel, Steven

    2017-12-01

    Historic long-term P application to sandy soils in NW-Europe has resulted in abundant sorption, saturation and eventually leaching of P from soil to the groundwater. Although many studies recognize the control of site-specific factors like soil texture and phosphate saturation degree (PSD), the regional-scaled relevance of effects exerted by single factors controlling P leaching is unclear. Very large observational datasets of soil and groundwater P content are furthermore required to reveal indirect controls of soil traits through mediating soil variables. We explored co-variation of phreatic groundwater orthophosphate (o-P) concentration and soil factors in sandy soils in Flanders, Belgium. Correlation analyses were complemented with an exploratory model derived using 'path analysis'. Data of oxalate-extractable Al, Fe, P and pH KCl , phosphate sorption capacity (PSC) and PSD in three depth layers (0-30, 30-60, 60-90 cm), topsoil SOC, % clay and groundwater depth (fluctuation) were interpolated to predict soil properties on exact locations of a very extensive net of groundwater monitoring wells. The mean PSD was only poorly correlated to groundwater o-P concentration, indicating the overriding control of other factors in the transport of P to the groundwater. A significant (P soil pH and groundwater table depth than by PSD indicates the likely oversimplification of the latter index to measure the long-term potential risk of P leaching. Accounting for controls on leaching not included in PSD via an alternative index, however, seems problematic as in Flanders for example groundwater o-P turned out to be higher in finer textured soils or soils with higher pedogenic Fe content, probably because of their lower pedogenic Al content and higher soil pH. Path analysis of extensive soil and groundwater datasets seems a viable way to identify prime local determinants of soil P leaching and could be further on used for 'ground-truthing' more complex P-migration simulation

  19. Investigation of density-wave oscillation in parallel boiling channels under high pressure

    International Nuclear Information System (INIS)

    Ming Xiao; Xuejun Chen; Mingyuan Zhang

    1992-01-01

    This paper presents experimental results on density-wave instability in parallel boiling channels. Experiments have been done in a high pressure steam-water loop. Different types of two-phase flow instabilities have been observed, including density-wave oscillation, pressure-drop type oscillation, thermal oscillation and secondary density-wave oscillation. The secondary density-wave oscillation appears at very low exit steam quality (less than 0.1) and at the positive portion of Δ P-G curves with both channels' flow rate oscillating in phase. Density-wave oscillation can appear at pressure up to 192 bar and disappear over 207 bar. (6 figures) (Author)

  20. Modeling the potential impacts of climate change on the water table level of selected forested wetlands in the southeastern United States

    OpenAIRE

    Zhu, Jie; Sun, Ge; Li, Wenhong; Zhang, Yu; Miao, Guofang; Noormets, Asko; McNulty, Steve G.; King, John S.; Kumar, Mukesh; Wang, Xuan

    2017-01-01

    The southeastern United States hosts extensive forested wetlands, providing ecosystem services including carbon sequestration, water quality improvement, groundwater recharge, and wildlife habitat. However, these wetland ecosystems are dependent on local climate and hydrology, and are therefore at risk due to climate and land use change. This study develops site-specific empirical hydrologic models for five forested wetlands with different characteristics by analyzing long-t...

  1. Tomographic examination table

    International Nuclear Information System (INIS)

    Redington, R.W.; Henkes, J.L.

    1979-01-01

    Equipment is described for positioning and supporting patients during tomographic mammography using X-rays. The equipment consists of a table and fabric slings which permit the examination of a downward, pendant breast of a prone patient by allowing the breast to pass through a aperture in the table into a fluid filled container. The fluid has an X-ray absorption coefficient similar to that of soft human tissue allowing high density resolution radiography and permitting accurate detection of breast tumours. The shape of the equipment and the positioning of the patient allow the detector and X-ray source to rotate 360 0 about a vertical axis through the breast. This permits the use of relatively simple image reconstruction algorithms and a divergent X-ray geometry. (UK)

  2. Inertial Oscillations and the Galilean Transformation

    Science.gov (United States)

    Korotaev, G. K.

    2018-03-01

    This paper presents a general solution of shallow-water equations on the f-plane. The solution describes the generation of inertial oscillations by wind-pulse forcing over the background of currents arbitrarily changing in time and space in a homogeneous fluid. It is shown that the existence of such a complete solution of shallow-water equations on the f-plane is related to their invariance with respect to the generalized Galilean transformations. Examples of velocity hodographs of inertial oscillations developing over the background of a narrow jet are presented which explain the diversity in their forms.

  3. Seashore marine table quiz

    OpenAIRE

    Institute, Marine

    2013-01-01

    Develop an increasing awareness of plants and animals that live in local marine environments including the seashore, seas and oceans of Ireland. After learning all about the seashore and other marine related lessons, this quiz can be used to evaluate the student’s knowledge of the marine related living things and natural environments. The table quiz can be used as a guide, highlighting facts about the marine environment and some of the animals that live there.

  4. Table Tennis Club

    CERN Document Server

    Table Tennis Club

    2012-01-01

    2012 CERN Table Tennis Tournament As the campaign launched by the CERN medical service “Move! & Eat better” is designed in particular to encourage people at CERN to take more regular exercise, the CERN Table Tennis Club, with its traditional CERN Table Tennis Tournament is providing an excellent opportunity to practice moving. The tournament will take place at the Meyrin CTT, 2 rue de Livron, Saturday August 25, 2012, in the afternoon (starting at 13:30). It is open to all CERN staff, users, visitors and families, including of course summer students, who are strongly encouraged to participate. In order to register, simply send an E-mail to Jean-Pierre Revol (jean-pierre.revol@cern.ch). You may also find useful information on the Club Web page http://www.cern.ch/tabletennis CERN 2011 champion Savitha Flaecher, between the finalist Bertrand Mouches on her left, the winner of the consolation draw on her right (Sudarshan Paramesvaran), and far left, Denis Moriaud (semi-finalist a...

  5. SRTC - Gap Analysis Table

    International Nuclear Information System (INIS)

    M.L. Johnson

    2005-01-01

    The purpose of this document is to review the existing SRTC design against the ''Nuclear Safety Design Bases for License Application'' (NSDB) [Ref. 10] requirements and to identify codes and standards and supplemental requirements to meet these requirements. If these codes and standards and supplemental requirements can not fully meet these safety requirements then a ''gap'' is identified. These gaps will be identified here and addressed using the ''Site Rail Transfer Cart (SRTC) Design Development Plan'' [Ref. 14]. The codes and standards, supplemental requirements, and design development requirements are provided in the SRTC and associated rails gap analysis table in Appendix A. Because SRTCs are credited with performing functions important to safety (ITS) in the NSDB [Ref. 10], design basis requirements are applicable to ensure equipment is available and performs required safety functions when needed. The gap analysis table is used to identify design objectives and provide a means to satisfy safety requirements. To ensure that the SRTC and rail design perform required safety Functions and meet performance criteria, this portion of the gap analysis table supplies codes and standards sections and the supplemental requirements and identifies design development requirements, if needed

  6. Global Reference Tables Services Architecture

    Data.gov (United States)

    Social Security Administration — This database stores the reference and transactional data used to provide a data-driven service access method to certain Global Reference Table (GRT) service tables.

  7. Aggregation Algorithms in Heterogeneous Tables

    Directory of Open Access Journals (Sweden)

    Titus Felix FURTUNA

    2006-01-01

    Full Text Available The heterogeneous tables are most used in the problem of aggregation. A solution for this problem is to standardize these tables of figures. In this paper, we proposed some methods of aggregation based on the hierarchical algorithms.

  8. TABLE OF CONTENTS TABLE OF CONTENTS

    African Journals Online (AJOL)

    eobe

    Effects of Variability in the Pozzolanic Properties of Rice Husk. Ash on the ... on Semi-Infinite Elastic Soils using Fourier Transform Method. H. N. Onah, N. N. ... Al – Si – Mg Alloy in Simulated Sea Water Environment. S. M. Adams, S. A. Yaro,.

  9. Observation of Quasichanneling Oscillations

    International Nuclear Information System (INIS)

    Wistisen, T. N.; Mikkelsen, R. E.; Uggerhoj, University I.; Wienands, University; Markiewicz, T. W.

    2017-01-01

    Here, we report on the first experimental observations of quasichanneling oscillations, recently seen in simulations and described theoretically. Although above-barrier particles penetrating a single crystal are generally seen as behaving almost as in an amorphous substance, distinct oscillation peaks nevertheless appear for particles in that category. The quasichanneling oscillations were observed at SLAC National Accelerator Laboratory by aiming 20.35 GeV positrons and electrons at a thin silicon crystal bent to a radius of R = 0.15 m, exploiting the quasimosaic effect. For electrons, two relatively faint quasichanneling peaks were observed, while for positrons, seven quasichanneling peaks were clearly identified.

  10. LSND neutrino oscillation results

    International Nuclear Information System (INIS)

    Louis, W.C.

    1996-01-01

    In the past several years, a number of experiments have searched for neutrino oscillations, where a neutrino of one type (say bar ν μ ) spontaneously transforms into a neutrino of another type (say bar ν e ). For this phenomenon to occur, neutrinos must be massive and the apparent conservation law of lepton families must be violated. In 1995 the LSND experiment published data showing candidate events that are consistent with bar ν μ oscillations. Additional data are reported here which provide stronger evidence for neutrino oscillations

  11. Neutrino Oscillation Physics

    International Nuclear Information System (INIS)

    Kayser, Boris

    2014-01-01

    To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures

  12. Neutrino Oscillation Physics

    Energy Technology Data Exchange (ETDEWEB)

    Kayser, Boris [Fermilab (United States)

    2014-07-01

    To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures.

  13. Oscillator, neutron modulator

    International Nuclear Information System (INIS)

    Agaisse, R.; Leguen, R.; Ombredane, D.

    1960-01-01

    The authors present a mechanical device and an electronic control circuit which have been designed to sinusoidally modulate the reactivity of the Proserpine atomic pile. The mechanical device comprises an oscillator and a mechanism assembly. The oscillator is made of cadmium blades which generate the reactivity oscillation. The mechanism assembly comprises a pulse generator for cycle splitting, a gearbox and an engine. The electronic device comprises or performs pulse detection, an on-off device, cycle pulse shaping, phase separation, a dephasing amplifier, electronic switches, counting scales, and control devices. All these elements are briefly presented

  14. OSCILLATING FILAMENTS. I. OSCILLATION AND GEOMETRICAL FRAGMENTATION

    Energy Technology Data Exchange (ETDEWEB)

    Gritschneder, Matthias; Heigl, Stefan; Burkert, Andreas, E-mail: gritschm@usm.uni-muenchen.de [University Observatory Munich, LMU Munich, Scheinerstrasse 1, D-81679 Munich (Germany)

    2017-01-10

    We study the stability of filaments in equilibrium between gravity and internal as well as external pressure using the grid-based AMR code RAMSES. A homogeneous, straight cylinder below a critical line mass is marginally stable. However, if the cylinder is bent, such as with a slight sinusoidal perturbation, an otherwise stable configuration starts to oscillate, is triggered into fragmentation, and collapses. This previously unstudied behavior allows a filament to fragment at any given scale, as long as it has slight bends. We call this process “geometrical fragmentation.” In our realization, the spacing between the cores matches the wavelength of the sinusoidal perturbation, whereas up to now, filaments were thought to be only fragmenting on the characteristic scale set by the mass-to-line ratio. Using first principles, we derive the oscillation period as well as the collapse timescale analytically. To enable a direct comparison with observations, we study the line-of-sight velocity for different inclinations. We show that the overall oscillation pattern can hide the infall signature of cores.

  15. VIDENTE 1.1: a graphical user interface and decision support system for stochastic modelling of water table fluctuations at a single location; includes documentation of the programs KALMAX, KALTFN, SSD and EMERALD and introductions to stochastic modelling; 2nd rev. ed

    NARCIS (Netherlands)

    Bierkens, M.F.P.; Bron, W.A.; Knotters, M.

    2002-01-01

    A description is given of the program VIDENTE. VIDENTE contains a decision support system to choose between different models for stochastic modelling of water-table depths and a graphical user interface to facilitate operating and running four implemented models: KALMAX, KALTFN, SSD and EMERALD. In

  16. Florida Agriculture - Utilizing TRMM to Analyze Sea Breeze Thunderstorm Patterns During El Nino Southern Oscillations and Their Effects Upon Available Fresh Water for South Florida Agricultural Planning and Management

    Science.gov (United States)

    Billiot, Amanda; Lee, Lucas; McKee, Jake; Cooley, Zachary Clayton; Mitchell, Brandie

    2010-01-01

    This project utilizes Tropical Rainfall Measuring Mission (TRMM) and Landsat satellite data to assess the impact of sea breeze precipitation upon areas of agricultural land use in southern Florida. Water is a critical resource to agriculture, and the availability of water for agricultural use in Florida continues to remain a key issue. Recent projections of statewide water use by 2020 estimate that 9.3 billion gallons of water per day will be demanded, and agriculture represents 47% of this demand (Bronson 2003). Farmers have fewer options for water supplies than public users and are often limited to using available supplies from surface and ground water sources which depend in part upon variable weather patterns. Sea breeze thunderstorms are responsible for much of the rainfall delivered to Florida during the wet season (May-October) and have been recognized as an important overall contributor of rainfall in southern Florida (Almeida 2003). TRMM satellite data was used to analyze how sea breeze-induced thunderstorms during El Nino and La Nina affected interannual patterns of precipitation in southern Florida from 1998-2009. TRMM's Precipitation Radar and Microwave Imager provide data to quantify water vapor in the atmosphere, precipitation rates and intensity, and the distribution of precipitation. Rainfall accumulation data derived from TRMM and other microwave sensors were used to analyze the temporal and spatial variations of rainfall during each phase of the El Nino Southern Oscillation (ENSO). Through the use of TRMM and Landsat, slight variations were observed, but it was determined that neither sea breeze nor total rainfall patterns in South Florida were strongly affected by ENSO during the study period. However, more research is needed to characterize the influence of ENSO on summer weather patterns in South Florida. This research will provide the basis for continued observations and study with the Global Precipitation Measurement Mission.

  17. Again on neutrino oscillations

    International Nuclear Information System (INIS)

    Bilenky, S.M.; Pontecorvo, B.

    1976-01-01

    The general case is treated of a weak interaction theory in which a term violating lepton charges is present. In such a scheme the particles with definite masses are Majorana neutrinos (2N if in the weak interaction participate N four-component neutrinos). Neutrino oscillations are discussed and it is shown that the minimum average intensity at the earth of solar neutrinos is 1/2N of the intensity expected when oscillations are absent

  18. Oscillators and operational amplifiers

    OpenAIRE

    Lindberg, Erik

    2005-01-01

    A generalized approach to the design of oscillators using operational amplifiers as active elements is presented. A piecewise-linear model of the amplifier is used so that it make sense to investigate the eigenvalues of the Jacobian of the differential equations. The characteristic equation of the general circuit is derived. The dynamic nonlinear transfer characteristic of the amplifier is investigated. Examples of negative resistance oscillators are discussed.

  19. Chaotic solar oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blacher, S; Perdang, J [Institut d' Astrophysique, B-4200 Cointe-Ougree (Belgium)

    1981-09-01

    A numerical experiment on Hamiltonian oscillations demonstrates the existence of chaotic motions which satisfy the property of phase coherence. It is observed that the low-frequency end of the power spectrum of such motions is remarkably similar in structure to the low-frequency SCLERA spectra. Since the smallness of the observed solar amplitudes is not a sufficient mathematical ground for inefficiency of non-linear effects the possibility of chaos among solar oscillations cannot be discarded a priori.

  20. Artificial recharge of the water-table aquifer in the latian volcano in Rome province; Ricarica artificiale dalla falda acquifera presente nel vulcano laziale in Provincia di Roma

    Energy Technology Data Exchange (ETDEWEB)

    Bersani, P.; Piotti, A. [Ambito Territoriale Ottimale, Lazio Centrale, Rome (Italy)

    2001-06-01

    The zone of the Latian Volcano extends in an area of about 1.500 km{sup 2} in the south-est of Rome. This area is thickly peopled, owing to the presence of many towns (Velletri, Frascati, Albano, etc.) in the central share of the volcanic edifice. Actually the volcanic edifice of Alban Hills shows in the central and higher area, a large caldera (Tuscolana-Artemisia). This caldera has a sub-circular form wide 10 km in diameter and 75 km{sup 2} in area. The excessive groundwater drawing by wells caused the depauperation of underground resources so to produce a real crisis since 1984. To restore of water balance of the aquifer of the Latian Volcano, an important contribution could be given by the artificial recharge of the higher aquifer. This recharge could be done by allowing to meteoric water to inflitrate as much as possible in the underground by realization of an artificial lake; otherwise by making a series of little infiltration-basins together with infiltration-wells. Besides the realization of the artificial lake could give back to the landscape a characteristic component present in the past centuries until very recent times. [Italian] L'area del Vulcano Laziale si estende su una superficie di circa 1500 km{sup 2} a sud-est di Roma in un'area densamente popolata per la presenza di numerosi centri urbani (Velletri, Frascati, Albano, ecc.), ubicati nella parte centrale dell'ufficio vulcanico. Attualmente l'edificio vulcanico dei Colli Albani presenta in posizione centrale un'ampia caldera sommitale con forma subcircolare, con diametro medio di circa 10 km ed estensione di circa 75 km{sup 2}. Gli eccessivi prelievi di acqua sotterranea hanno condotto ad un impoverimento della risorsa idrica fino a determinare una vera e propria crisi manifestatasi a partire dal 1984. Per riequilibrare il bilancio idrico dell'acquifero del Vulcano Laziale, un contributo significativo potrebbe provenire dalla ricarica artificiale dell

  1. Case for neutrino oscillations

    International Nuclear Information System (INIS)

    Ramond, P.

    1982-01-01

    The building of a machine capable of producing an intense, well-calibrated beam of muon neutrinos is regarded by particle physicists with keen interest because of its ability of studying neutrino oscillations. The possibility of neutrino oscillations has long been recognized, but it was not made necessary on theoretical or experimental grounds; one knew that oscillations could be avoided if neutrinos were massless, and this was easily done by the conservation of lepton number. The idea of grand unification has led physicists to question the existence (at higher energies) of global conservation laws. The prime examples are baryon-number conservation, which prevents proton decay, and lepton-number conservation, which keeps neutrinos massless, and therefore free of oscillations. The detection of proton decay and neutrino oscillations would therefore be an indirect indication of the idea of Grand Unification, and therefore of paramount importance. Neutrino oscillations occur when neutrinos acquire mass in such a way that the neutrino mass eigenstates do not match the (neutrino) eigenstates produced by the weak interactions. We shall study the ways in which neutrinos can get mass, first at the level of the standard SU 2 x U 1 model, then at the level of its Grand Unification Generalizations

  2. Radionuclide table. Pt. 1

    International Nuclear Information System (INIS)

    Legrand, Jean; Perolat, J.-P.; Lagoutine, Frederic; Le Gallic, Yves.

    The evaluation of the following 29 radionuclides is presented: 22 Na, 24 Na, sup(24m)Na, 51 Cr, 54 Mn, 57 Co, 58 Co, sup(58m)Co, 60 Co, sup(60m)Co, 75 Se, 103 Ru, sup(103m)Rh, sup(110m)Ag- 110 Ag, 109 Cd, 125 Sb, sup(125mTe), 125 I, 133 Xe, sup(133m)Xe, 131 Cs, 134 Cs, sup(134m)Cs, 139 Ce, 144 Ce- 144 Pr, 144 Pr, 169 Er, 186 Re, 203 Hg. The introduction contains a brief description of radioactive processes and the evaluation rules followed. The best values and associated uncertainties are given for each radionuclide for the major parameters of the decay scheme and the radiation intensities emitted, together with a decay table. Gamma, X-rays and sometimes conversion electron spectra are also provided [fr

  3. Do muons oscillate?

    International Nuclear Information System (INIS)

    Dolgov, A.D.; Morozov, A.Yu.; Okun, L.B.; Schepkin, M.G.

    1997-01-01

    We develop a theory of the EPR-like effects due to neutrino oscillations in the π→μν decays. Its experimental implications are space-time correlations of the neutrino and muon when they are both detected, while the pion decay point is not fixed. However, the more radical possibility of μ-oscillations in experiments where only muons are detected (as suggested in hep-ph/9509261), is ruled out. We start by discussing decays of monochromatic pions, and point out a few ''paradoxes''. Then we consider pion wave packets, solve the ''paradoxes'', and show that the formulas for μν correlations can be transformed into the usual expressions, describing neutrino oscillations, as soon as the pion decay point is fixed. (orig.)

  4. Oscillations in neutron stars

    International Nuclear Information System (INIS)

    Hoeye, Gudrun Kristine

    1999-01-01

    We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l → 4) f-modes we were also able to derive a formula that determines II l+1 from II l and II l-1 to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n c , while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

  5. Oscillations in neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Hoeye, Gudrun Kristine

    1999-07-01

    We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l (>{sub )} 4) f-modes we were also able to derive a formula that determines II{sub l+1} from II{sub l} and II{sub l-1} to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n{sub c}, while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

  6. Symbol Tables and Branch Tables: Linking Applications Together

    Science.gov (United States)

    Handler, Louis M.

    2011-01-01

    This document explores the computer techniques used to execute software whose parts are compiled and linked separately. The computer techniques include using a branch table or indirect address table to connect the parts. Methods of storing the information in data structures are discussed as well as differences between C and C++.

  7. Oscillating Finite Sums

    KAUST Repository

    Alabdulmohsin, Ibrahim M.

    2018-03-07

    In this chapter, we use the theory of summability of divergent series, presented earlier in Chap. 4, to derive the analogs of the Euler-Maclaurin summation formula for oscillating sums. These formulas will, in turn, be used to perform many remarkable deeds with ease. For instance, they can be used to derive analytic expressions for summable divergent series, obtain asymptotic expressions of oscillating series, and even accelerate the convergence of series by several orders of magnitude. Moreover, we will prove the notable fact that, as far as the foundational rules of summability calculus are concerned, summable divergent series behave exactly as if they were convergent.

  8. Brownian parametric oscillators

    Science.gov (United States)

    Zerbe, Christine; Jung, Peter; Hänggi, Peter

    1994-05-01

    We discuss the stochastic dynamics of dissipative, white-noise-driven Floquet oscillators, characterized by a time-periodic stiffness. Thus far, little attention has been paid to these exactly solvable nonstationary systems, although they carry a rich potential for several experimental applications. Here, we calculate and discuss the mean values and variances, as well as the correlation functions and the Floquet spectrum. As one main result, we find for certain parameter values that the fluctuations of the position coordinate are suppressed as compared to the equilibrium value of a harmonic oscillator (parametric squeezing).

  9. Friedel oscillations in graphene

    DEFF Research Database (Denmark)

    Lawlor, J. A.; Power, S. R.; Ferreira, M.S.

    2013-01-01

    Symmetry breaking perturbations in an electronically conducting medium are known to produce Friedel oscillations in various physical quantities of an otherwise pristine material. Here we show in a mathematically transparent fashion that Friedel oscillations in graphene have a strong sublattice...... asymmetry. As a result, the presence of impurities and/or defects may impact the distinct graphene sublattices very differently. Furthermore, such an asymmetry can be used to explain the recent observations that nitrogen atoms and dimers are not randomly distributed in graphene but prefer to occupy one...

  10. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...... to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...

  11. Oscillating Finite Sums

    KAUST Repository

    Alabdulmohsin, Ibrahim M.

    2018-01-01

    In this chapter, we use the theory of summability of divergent series, presented earlier in Chap. 4, to derive the analogs of the Euler-Maclaurin summation formula for oscillating sums. These formulas will, in turn, be used to perform many remarkable deeds with ease. For instance, they can be used to derive analytic expressions for summable divergent series, obtain asymptotic expressions of oscillating series, and even accelerate the convergence of series by several orders of magnitude. Moreover, we will prove the notable fact that, as far as the foundational rules of summability calculus are concerned, summable divergent series behave exactly as if they were convergent.

  12. Oscillators from nonlinear realizations

    Science.gov (United States)

    Kozyrev, N.; Krivonos, S.

    2018-02-01

    We construct the systems of the harmonic and Pais-Uhlenbeck oscillators, which are invariant with respect to arbitrary noncompact Lie algebras. The equations of motion of these systems can be obtained with the help of the formalism of nonlinear realizations. We prove that it is always possible to choose time and the fields within this formalism in such a way that the equations of motion become linear and, therefore, reduce to ones of ordinary harmonic and Pais-Uhlenbeck oscillators. The first-order actions, that produce these equations, can also be provided. As particular examples of this construction, we discuss the so(2, 3) and G 2(2) algebras.

  13. Exigências hídricas da videira na Região do Submédio São Francisco Table grape water requirements in the Submedium São Francisco Region

    Directory of Open Access Journals (Sweden)

    JAQUELINE ÁVILA NETTO

    2000-08-01

    Full Text Available O trabalho objetivou a estimativa das necessidades hídricas da videira (Vitis vinifera L., cv. Itália, sob as condições edafoclimáticas da Região do Submédio São Francisco. A parte experimental foi conduzida no campo experimental de Bebedouro da Embrapa-Centro de Pesquisa Agropecuária do Trópico Semi-Árido, no município de Petrolina, PE, durante o período de maio a agosto de 1996. A evapotranspiração da cultura foi determinada pelo método do balanço hídrico no solo, e a evapotranspiração de referência foi estimada pelo método de Penman, visando avaliar o comportamento do coeficiente de cultura (Kc ao longo do ciclo da cultura. O parreiral, com cinco anos de idade, foi conduzido em sistema de latada a 2 m acima da superfície do solo, num espaçamento de 4 m x 2 m e irrigado diariamente por gotejamento. O consumo hídrico diário máximo da cultura foi de 4,33 mm dia-1, totalizando 333,6 mm no período de observações. Os valores de Kc variaram de 0,50 a 0,74. Determinou-se uma curva característica de Kc para o ciclo vegetativo da videira, a qual permite obter o Kc diário em função dos dias após a poda.This study used data of a field experiment conducted at the Bebedouro experimental base of the Embrapa-Centro de Pesquisa Agropecuária do Trópico Semi-Árido in Petrolina, PE, Brazil, from May to August, 1996, during the growing period of a five-year-old table grape (Vitis vinifera L., Italy cultivar. The plants were conducted in a two-meter above soil surface trellis system, four meters between rows by two meters between plants, and daily irrigated by trickling system. The crop evapotranspiration was determined by the soil water balance method, and the reference evapotranspiration was estimated by the method of Penman, used to analyse the behaviour of the crop coefficient (Kc throughout the crop growing period. The maximum crop daily water use was 4.33 mm d-1 and the total water consumption was 333.6 mm for the whole

  14. Oscillation Baselining and Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    2017-03-27

    PNNL developed a new tool for oscillation analysis and baselining. This tool has been developed under a new DOE Grid Modernization Laboratory Consortium (GMLC) Project (GM0072 - “Suite of open-source applications and models for advanced synchrophasor analysis”) and it is based on the open platform for PMU analysis. The Oscillation Baselining and Analysis Tool (OBAT) performs the oscillation analysis and identifies modes of oscillations (frequency, damping, energy, and shape). The tool also does oscillation event baselining (fining correlation between oscillations characteristics and system operating conditions).

  15. Chaotic synchronization of two complex nonlinear oscillators

    International Nuclear Information System (INIS)

    Mahmoud, Gamal M.; Mahmoud, Emad E.; Farghaly, Ahmed A.; Aly, Shaban A.

    2009-01-01

    Synchronization is an important phenomenon commonly observed in nature. It is also often artificially induced because it is desirable for a variety of applications in physics, applied sciences and engineering. In a recent paper [Mahmoud GM, Mohamed AA, Aly SA. Strange attractors and chaos control in periodically forced complex Duffing's oscillators. Physica A 2001;292:193-206], a system of periodically forced complex Duffing's oscillators was introduced and shown to display chaotic behavior and possess strange attractors. Such complex oscillators appear in many problems of physics and engineering, as, for example, nonlinear optics, deep-water wave theory, plasma physics and bimolecular dynamics. Their connection to solutions of the nonlinear Schroedinger equation has also been pointed out. In this paper, we study the remarkable phenomenon of chaotic synchronization on these oscillator systems, using active control and global synchronization techniques. We derive analytical expressions for control functions and show that the dynamics of error evolution is globally stable, by constructing appropriate Lyapunov functions. This means that, for a relatively large set initial conditions, the differences between the drive and response systems vanish exponentially and synchronization is achieved. Numerical results are obtained to test the validity of the analytical expressions and illustrate the efficiency of these techniques for inducing chaos synchronization in our nonlinear oscillators.

  16. Water table and the neutron moisture meter

    Energy Technology Data Exchange (ETDEWEB)

    Visvalingam, M [Hull Univ. (UK). Geography Dept.

    1975-12-01

    Measurements with a neutron moisture meter at Westlands, near Hull, showed count rates at capillary saturation to be within the error limits of count rates at full saturation. However, the saturation profiles in themselves were interesting as they indicated not only the zonation of the soil but also differences in drainable porosity when compared to count-rate profiles at the end of November.

  17. Water Table Recession in Subsurface Drained Soils

    OpenAIRE

    Moustafa, Mahmoud Mohamed; Yomota, Atsushi

    1999-01-01

    Theoretical drainage equations are intensively tested in many parts of humid and arid regions and are commonly used in drainage design. However, this is still a great concern in Japan as the drainage design is exclusively based on local experiences and empirical basis. There is a need therefore to evaluate the theoretical drainage equations under Japanese field conditions to recommend equations for design of subsurface drainage systems. This was the main motivation for this study. While drain...

  18. Use of Decision Tables to Simulate Management in SWAT+

    Directory of Open Access Journals (Sweden)

    Jeffrey G. Arnold

    2018-05-01

    Full Text Available Decision tables have been used for many years in data processing and business applications to simulate complex rule sets. Several computer languages have been developed based on rule systems and they are easily programmed in several current languages. Land management and river–reservoir models simulate complex land management operations and reservoir management in highly regulated river systems. Decision tables are a precise yet compact way to model the rule sets and corresponding actions found in these models. In this study, we discuss the suitability of decision tables to simulate management in the river basin scale Soil and Water Assessment Tool (SWAT+ model. Decision tables are developed to simulate automated irrigation and reservoir releases. A simple auto irrigation application of decision tables was developed using plant water stress as a condition for irrigating corn in Texas. Sensitivity of the water stress trigger and irrigation application amounts were shown on soil moisture and corn yields. In addition, the Grapevine Reservoir near Dallas, Texas was used to illustrate the use of decision tables to simulate reservoir releases. The releases were conditioned on reservoir volumes and flood season. The release rules as implemented by the decision table realistically simulated flood releases as evidenced by a daily Nash–Sutcliffe Efficiency (NSE of 0.52 and a percent bias of −1.1%. Using decision tables to simulate management in land, river, and reservoir models was shown to have several advantages over current approaches, including: (1 mature technology with considerable literature and applications; (2 ability to accurately represent complex, real world decision-making; (3 code that is efficient, modular, and easy to maintain; and (4 tables that are easy to maintain, support, and modify.

  19. Volume tables for red alder.

    Science.gov (United States)

    Floyd A. Johnson; R. M. Kallander; Paul G. Lauterbach

    1949-01-01

    The increasing importance of red alder as a commercial species in the Pacific Northwest has prompted the three agencies listed above to pool their tree measurement data for the construction of standard regional red alder volume tables. The tables included here were based on trees from a variety of sites and form classes. Approximately one quarter of the total number of...

  20. From excitability to oscillations

    DEFF Research Database (Denmark)

    Postnov, D. E.; Neganova, A. Y.; Jacobsen, J. C. B.

    2013-01-01

    One consequence of cell-to-cell communication is the appearance of synchronized behavior, where many cells cooperate to generate new dynamical patterns. We present a simple functional model of vasomotion based on the concept of a two-mode oscillator with dual interactions: via relatively slow dif...

  1. Neutrino oscillation experiments

    International Nuclear Information System (INIS)

    Camilleri, L.

    1996-01-01

    Neutrino oscillation experiments (ν μ →ν e and ν μ →ν τ ) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs

  2. A simple violin oscillator

    Science.gov (United States)

    Jones, R. T.

    1976-01-01

    For acoustic tests the violin is driven laterally at the bridge by a small speaker of the type commonly found in pocket transistor radios. An audio oscillator excites the tone which is picked up by a sound level meter. Gross patterns of vibration modes are obtained by the Chladni method.

  3. Nonlinearity in oscillating bridges

    Directory of Open Access Journals (Sweden)

    Filippo Gazzola

    2013-09-01

    Full Text Available We first recall several historical oscillating bridges that, in some cases, led to collapses. Some of them are quite recent and show that, nowadays, oscillations in suspension bridges are not yet well understood. Next, we survey some attempts to model bridges with differential equations. Although these equations arise from quite different scientific communities, they display some common features. One of them, which we believe to be incorrect, is the acceptance of the linear Hooke law in elasticity. This law should be used only in presence of small deviations from equilibrium, a situation which does not occur in widely oscillating bridges. Then we discuss a couple of recent models whose solutions exhibit self-excited oscillations, the phenomenon visible in real bridges. This suggests a different point of view in modeling equations and gives a strong hint how to modify the existing models in order to obtain a reliable theory. The purpose of this paper is precisely to highlight the necessity of revisiting the classical models, to introduce reliable models, and to indicate the steps we believe necessary to reach this target.

  4. Integrated optoelectronic oscillator.

    Science.gov (United States)

    Tang, Jian; Hao, Tengfei; Li, Wei; Domenech, David; Baños, Rocio; Muñoz, Pascual; Zhu, Ninghua; Capmany, José; Li, Ming

    2018-04-30

    With the rapid development of the modern communication systems, radar and wireless services, microwave signal with high-frequency, high-spectral-purity and frequency tunability as well as microwave generator with light weight, compact size, power-efficient and low cost are increasingly demanded. Integrated microwave photonics (IMWP) is regarded as a prospective way to meet these demands by hybridizing the microwave circuits and the photonics circuits on chip. In this article, we propose and experimentally demonstrate an integrated optoelectronic oscillator (IOEO). All of the devices needed in the optoelectronic oscillation loop circuit are monolithically integrated on chip within size of 5×6cm 2 . By tuning the injection current to 44 mA, the output frequency of the proposed IOEO is located at 7.30 GHz with phase noise value of -91 dBc/Hz@1MHz. When the injection current is increased to 65 mA, the output frequency can be changed to 8.87 GHz with phase noise value of -92 dBc/Hz@1MHz. Both of the oscillation frequency can be slightly tuned within 20 MHz around the center oscillation frequency by tuning the injection current. The method about improving the performance of IOEO is carefully discussed at the end of in this article.

  5. The variational spiked oscillator

    International Nuclear Information System (INIS)

    Aguilera-Navarro, V.C.; Ullah, N.

    1992-08-01

    A variational analysis of the spiked harmonic oscillator Hamiltonian -d 2 / d x 2 + x 2 + δ/ x 5/2 , δ > 0, is reported in this work. A trial function satisfying Dirichlet boundary conditions is suggested. The results are excellent for a large range of values of the coupling parameter. (author)

  6. Neutrino oscillation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Camilleri, L [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-11-01

    Neutrino oscillation experiments ({nu}{sub {mu}}{yields}{nu}{sub e} and {nu}{sub {mu}}{yields}{nu}{sub {tau}}) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs.

  7. MCNPX Model/Table Comparison

    International Nuclear Information System (INIS)

    Hendricks, J.S.

    2003-01-01

    MCNPX is a Monte Carlo N-Particle radiation transport code extending the capabilities of MCNP4C. As with MCNP, MCNPX uses nuclear data tables to transport neutrons, photons, and electrons. Unlike MCNP, MCNPX also uses (1) nuclear data tables to transport protons; (2) physics models to transport 30 additional particle types (deuterons, tritons, alphas, pions, muons, etc.); and (3) physics models to transport neutrons and protons when no tabular data are available or when the data are above the energy range (20 to 150 MeV) where the data tables end. MCNPX can mix and match data tables and physics models throughout a problem. For example, MCNPX can model neutron transport in a bismuth germinate (BGO) particle detector by using data tables for bismuth and oxygen and using physics models for germanium. Also, MCNPX can model neutron transport in UO 2 , making the best use of physics models and data tables: below 20 MeV, data tables are used; above 150 MeV, physics models are used; between 20 and 150 MeV, data tables are used for oxygen and models are used for uranium. The mix-and-match capability became available with MCNPX2.5.b (November 2002). For the first time, we present here comparisons that calculate radiation transport in materials with various combinations of data charts and model physics. The physics models are poor at low energies (<150 MeV); thus, data tables should be used when available. Our comparisons demonstrate the importance of the mix-and-match capability and indicate how well physics models work in the absence of data tables

  8. A prelanding assessment of the ice table depth and ground ice characteristics in Martian permafrost at the Phoenix landing site

    Science.gov (United States)

    Mellon, M.T.; Boynton, W.V.; Feldman, W.C.; Arvidson, R. E.; Titus, Joshua T.N.; Bandfield, L.; Putzig, N.E.; Sizemore, H.G.

    2009-01-01

    We review multiple estimates of the ice table depth at potential Phoenix landing sites and consider the possible state and distribution of subsurface ice. A two-layer model of ice-rich material overlain by ice-free material is consistent with both the observational and theoretical lines of evidence. Results indicate ground ice to be shallow and ubiquitous, 2-6 cm below the surface. Undulations in the ice table depth are expected because of the thermodynamic effects of rocks, slopes, and soil variations on the scale of the Phoenix Lander and within the digging area, which can be advantageous for analysis of both dry surficial soils and buried ice-rich materials. The ground ice at the ice table to be sampled by the Phoenix Lander is expected to be geologically young because of recent climate oscillations. However, estimates of the ratio of soil to ice in the ice-rich subsurface layer suggest that that the ice content exceeds the available pore space, which is difficult to reconcile with existing ground ice stability and dynamics models. These high concentrations of ice may be the result of either the burial of surface snow during times of higher obliquity, initially high-porosity soils, or the migration of water along thin films. Measurement of the D/H ratio within the ice at the ice table and of the soil-to-ice ratio, as well as imaging ice-soil textures, will help determine if the ice is indeed young and if the models of the effects of climate change on the ground ice are reasonable. Copyright 2008 by the American Geophysical Union.

  9. Qualification of the calculational methods of the fluence in the pressurised water reactors. Improvement of the cross sections treatment by the probability table method; Qualification des methodes de calculs de fluence dans les reacteurs a eau pressurisee. Amelioration du traitement des sections efficaces par la methode des tables de probabilite

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, S H

    1994-01-01

    It is indispensable to know the fluence on the nuclear reactor pressure vessel. The cross sections and their treatment have an important rule to this problem. In this study, two ``benchmarks`` have been interpreted by the Monte Carlo transport program TRIPOLI to qualify the calculational method and the cross sections used in the calculations. For the treatment of the cross sections, the multigroup method is usually used but it exists some problems such as the difficulty to choose the weighting function and the necessity of a great number of energy to represent well the cross section`s fluctuation. In this thesis, we propose a new method called ``Probability Table Method`` to treat the neutron cross sections. For the qualification, a program of the simulation of neutron transport by the Monte Carlo method in one dimension has been written; the comparison of multigroup`s results and probability table`s results shows the advantages of this new method. The probability table has also been introduced in the TRIPOLI program; the calculational results of the iron deep penetration benchmark has been improved by comparing with the experimental results. So it is interest to use this new method in the shielding and neutronic calculation. (author). 42 refs., 109 figs., 36 tabs.

  10. Anharmonic oscillator and Bogoliubov transformation

    International Nuclear Information System (INIS)

    Pattnayak, G.C.; Torasia, S.; Rath, B.

    1990-01-01

    The anharmonic oscillator occupies a cornerstone in many problems in physics. It was observed that none of the authors have tested Bogoliubov transformation to study anharmonic oscillator. The groundstate energy of the anharmonic oscillator is studied using Bogoliubov transformation and the results presented. (author)

  11. Bimodal oscillations in nephron autoregulation

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A.N.; Mosekilde, Erik

    2002-01-01

    The individual functional unit of the kidney (the nephron) displays oscillations in its pressure and flow regulation at two different time scales: fast oscillations associated with a myogenic dynamics of the afferent arteriole, and slower oscillations arising from a delay in the tubuloglomerular ...

  12. Disponibilidade de água em pomar de citros submetido a poda e subsolagem em latossolo amarelo dos tabuleiros costeiros Water availability in citros orchard, under prunning and subsoiling, on yellow latosol of coastal table land

    Directory of Open Access Journals (Sweden)

    Laercio Duarte Souza

    2004-04-01

    Full Text Available Um pomar de laranja 'Baianinha' enxertada sobre limão 'Cravo' com 10 anos de idade, recebeu, neste período, práticas culturais de roçadeira no inverno e grade no verão, com três capinas manuais na linha por ano. Instalado em Latossolo Amarelo, nos Tabuleiros Costeiros, apresentava problemas de fitossanidade e produtividade, oriundos do impedimento ao desenvolvimento de raízes e exploração do solo e da água, ocasionados pelas camadas coesas características destes solos. Com o objetivo de aumentar a disponibilidade de água no solo para as plantas, aplicaram-se tratamentos de subsolagem, em interação com diferentes sistemas de poda da parte aérea. Realizaram-se uma amostragem de parâmetros físicos e químicos do solo, e um monitoramento da água nas profundidades de 0,30; 0,50; 0,70; 0,90; 1,10; 1,30 e 1,50 m com sonda de nêutrons, no período de dois anos ( 1º março/96 a 1º março/98, com duas repetições, em leituras semanais. As melhores respostas foram obtidas com os tratamentos subsolados sem poda e com poda leve. O tratamento subsolado com poda brusca apresentou as maiores deficiências de água disponível no solo, superando, inclusive, a testemunha.A ten years old orchard of orange 'Baianinha' grafted on lemon 'Cravo' was submitted, to cultural practices of mower in the winter and grating in the summer, with three hand weedings, within crop line, a year. The work was carried out in a Yellow Latosol in the Coastal Table Land ecosystem. The orchard presented phytopathological and production problems, which were attributed to the impediment of the development of roots and storage of water, caused by the cohesive layers, characteristics of these soils. This study was to increase the water availability to the plants by treatments with subsoiling combined with different pruning systems. Physical and chemical parameters of the soil were evaluated and the behavior of the water, in the depths of 0,30; 0,50; 0,70; 0,90; 1,10; 1

  13. Observation and analysis of oscillations in linear accelerators

    International Nuclear Information System (INIS)

    Seeman, J.T.

    1991-11-01

    This report discusses the following on oscillation in linear accelerators: Betatron Oscillations; Betatron Oscillations at High Currents; Transverse Profile Oscillations; Transverse Profile Oscillations at High Currents.; Oscillation and Profile Transient Jitter; and Feedback on Transverse Oscillations

  14. MCNPX Model/Table Comparison

    CERN Document Server

    Hendricks, J S

    2003-01-01

    MCNPX is a Monte Carlo N-Particle radiation transport code extending the capabilities of MCNP4C. As with MCNP, MCNPX uses nuclear data tables to transport neutrons, photons, and electrons. Unlike MCNP, MCNPX also uses (1) nuclear data tables to transport protons; (2) physics models to transport 30 additional particle types (deuterons, tritons, alphas, pions, muons, etc.); and (3) physics models to transport neutrons and protons when no tabular data are available or when the data are above the energy range (20 to 150 MeV) where the data tables end. MCNPX can mix and match data tables and physics models throughout a problem. For example, MCNPX can model neutron transport in a bismuth germinate (BGO) particle detector by using data tables for bismuth and oxygen and using physics models for germanium. Also, MCNPX can model neutron transport in UO sub 2 , making the best use of physics models and data tables: below 20 MeV, data tables are used; above 150 MeV, physics models are used; between 20 and 150 MeV, data t...

  15. Reactor oscillator - Proposal of the organisation for oscillator operation; Reaktorski oscilator - Predlog organizacije rada na oscilatoru

    Energy Technology Data Exchange (ETDEWEB)

    Lolic, B; Loloc, B [Institute of Nuclear Sciences Boris Kidric, Laboratorija za fiziku reaktora, Vinca, Beograd (Serbia and Montenegro)

    1961-12-15

    The organizational structure for operating the reactor with the reactor oscillator describes the duties of the reactor operators; staff responsible for operating the oscillator who are responsible for measurements, preparation of the samples and further treatment of the obtained results.

  16. Quenching oscillating behaviors in fractional coupled Stuart-Landau oscillators

    Science.gov (United States)

    Sun, Zhongkui; Xiao, Rui; Yang, Xiaoli; Xu, Wei

    2018-03-01

    Oscillation quenching has been widely studied during the past several decades in fields ranging from natural sciences to engineering, but investigations have so far been restricted to oscillators with an integer-order derivative. Here, we report the first study of amplitude death (AD) in fractional coupled Stuart-Landau oscillators with partial and/or complete conjugate couplings to explore oscillation quenching patterns and dynamics. It has been found that the fractional-order derivative impacts the AD state crucially. The area of the AD state increases along with the decrease of the fractional-order derivative. Furthermore, by introducing and adjusting a limiting feedback factor in coupling links, the AD state can be well tamed in fractional coupled oscillators. Hence, it provides one an effective approach to analyze and control the oscillating behaviors in fractional coupled oscillators.

  17. Pattern formation in arrays of chemical oscillators

    Indian Academy of Sciences (India)

    Chemical oscillators; phase flip; oscillation death. PACS No. 05.45 .... array oscillate (with varying amplitudes and frequencies), while the others experience oscillation death .... Barring the boundary cells, one observes near phase flip and near ...

  18. Analysis of uncertainties, associated to the calculating hypothesis, in discharge tables for high flows estimating, based on mathematics models for calculating water surface profiles fore steady gradually varied flow; Analisis de las incertidumbres, asociadas a las hipotesis de calculo, en la estimacion de curvas de gasto para crcidas, basada en el empleo de modelo matematico de calculo hidraulico en regimen permanente

    Energy Technology Data Exchange (ETDEWEB)

    Aldana Valverde, A. L.; Gonzalez Rodriguez, J. C.

    1999-08-01

    In this paper are analyzed some of the most important factors which can influence on the results of calculating water surface profiles for steady gradually varied flow. In this case, the objective of this kind of modeling, has been the estimation of discharges tables for high flows of river station gages connected to the hydrologic automatic information system (SAIH) of the Confederacion Hidrografica del Sur de Espana, system named red Hidrosur. (Author) 3 refs

  19. Elekta Precise Table characteristics of IGRT remote table positioning

    International Nuclear Information System (INIS)

    Riis, Hans L.; Zimmermann, Sune J.

    2009-01-01

    Cone beam CT is a powerful tool to ensure an optimum patient positioning in radiotherapy. When cone beam CT scan of a patient is acquired, scan data of the patient are compared and evaluated against a reference image set and patient position offset is calculated. Via the linac control system, the patient is moved to correct for position offset and treatment starts. This procedure requires a reliable system for movement of patient. In this work we present a new method to characterize the reproducibility, linearity and accuracy in table positioning. The method applies to all treatment tables used in radiotherapy. Material and methods. The table characteristics are investigated on our two recent Elekta Synergy Platforms equipped with Precise Table installed in a shallow pit concrete cavity. Remote positioning of the table uses the auto set-up (ASU) feature in the linac control system software Desktop Pro R6.1. The ASU is used clinically to correct for patient positioning offset calculated via cone beam CT (XVI)-software. High precision steel rulers and a USB-microscope has been used to detect the relative table position in vertical, lateral and longitudinal direction. The effect of patient is simulated by applying external load on the iBEAM table top. For each table position an image is exposed of the ruler and display values of actual table position in the linac control system is read out. The table is moved in full range in lateral direction (50 cm) and longitudinal direction (100 cm) while in vertical direction a limited range is used (40 cm). Results and discussion. Our results show a linear relation between linac control system read out and measured position. Effects of imperfect calibration are seen. A reproducibility within a standard deviation of 0.22 mm in lateral and longitudinal directions while within 0.43 mm in vertical direction has been observed. The usage of XVI requires knowledge of the characteristics of remote table positioning. It is our opinion

  20. The Periodic Table in Croatia

    Directory of Open Access Journals (Sweden)

    Raos, N.

    2011-12-01

    Full Text Available The Croatian (Yugoslav Academy of Sciences and Arts was the first academy to elect D. I. Mendeleev as its honorary member (1882, whereas the periodic table of the elements has been taught regularly at the Zagreb University since 1888. The early interest of Croatian chemists in the periodic table should be attributed primarily to their pan-Slavic attitude, particularly as proof that Slavic people were able to produce "their own Newtons" (M. V. Lomonosov and D. I. Mendeleev. Such enthusiastic views, however, did not help in analyzing the contribution of Mendeleev and other scientists to the discovery and development of the periodic table of the elements.

  1. Entanglement in neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blasone, M.; Dell' Anno, F.; De Siena, S.; Illuminati, F. [Universita degli Studi di Salerno Via Ponte don Melillon, Dipt. di Matematica e Informatica, Fisciano SA (Italy); INFN Sezione di Napoli, Gruppo collegato di Salerno - Baronissi SA (Italy); Dell' Anno, F.; De Siena, S.; Illuminati, F. [CNR-INFM Coherentia - Napoli (Italy); Blasone, M. [ISI Foundation for Scientific Interchange, Torino (Italy)

    2009-03-15

    Flavor oscillations in elementary particle physics are related to multimode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged-lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks. (authors)

  2. Nonlinear (Anharmonic Casimir Oscillator

    Directory of Open Access Journals (Sweden)

    Habibollah Razmi

    2011-01-01

    Full Text Available We want to study the dynamics of a simple linear harmonic micro spring which is under the influence of the quantum Casimir force/pressure and thus behaves as a (an nonlinear (anharmonic Casimir oscillator. Generally, the equation of motion of this nonlinear micromechanical Casimir oscillator has no exact solvable (analytical solution and the turning point(s of the system has (have no fixed position(s; however, for particular values of the stiffness of the micro spring and at appropriately well-chosen distance scales and conditions, there is (are approximately sinusoidal solution(s for the problem (the variable turning points are collected in a very small interval of positions. This, as a simple and elementary plan, may be useful in controlling the Casimir stiction problem in micromechanical devices.

  3. Entanglement in neutrino oscillations

    International Nuclear Information System (INIS)

    Blasone, M.; Dell'Anno, F.; De Siena, S.; Illuminati, F.; Dell'Anno, F.; De Siena, S.; Illuminati, F.; Blasone, M.

    2009-01-01

    Flavor oscillations in elementary particle physics are related to multimode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged-lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks. (authors)

  4. Acoustics waves and oscillations

    CERN Document Server

    Sen, S.N.

    2013-01-01

    Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter...

  5. Discrete repulsive oscillator wavefunctions

    International Nuclear Information System (INIS)

    Munoz, Carlos A; Rueda-Paz, Juvenal; Wolf, Kurt Bernardo

    2009-01-01

    For the study of infinite discrete systems on phase space, the three-dimensional Lorentz algebra and group, so(2,1) and SO(2,1), provide a discrete model of the repulsive oscillator. Its eigenfunctions are found in the principal irreducible representation series, where the compact generator-that we identify with the position operator-has the infinite discrete spectrum of the integers Z, while the spectrum of energies is a double continuum. The right- and left-moving wavefunctions are given by hypergeometric functions that form a Dirac basis for l 2 (Z). Under contraction, the discrete system limits to the well-known quantum repulsive oscillator. Numerical computations of finite approximations raise further questions on the use of Dirac bases for infinite discrete systems.

  6. Neutrino Masses and Oscillations

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit; Treille, Daniel

    2002-01-01

    This course will not cover its subject in the customary way. The emphasis will be on the simple theoretical concepts (helicity, handedness, chirality, Majorana masses) which are obscure in most of the literature, and on the quantum mechanics of oscillations, that ALL books get wrong. Which, hopefully, will not deter me from discussing some of the most interesting results from the labs and from the cosmos.

  7. Oscillations in quasineutral plasmas

    International Nuclear Information System (INIS)

    Grenier, E.

    1996-01-01

    The purpose of this article is to describe the limit, as the vacuum electric permittivity goes to zero, of a plasma physics system, deduced from the Vlasov-Poisson system for special initial data (distribution functions which are analytic in the space variable, with compact support in velocity), a limit also called open-quotes quasineutral regimeclose quotes of the plasma, and the related oscillations of the electric field, with high frequency in time. 20 refs

  8. Density oscillations within hadrons

    International Nuclear Information System (INIS)

    Arnold, R.; Barshay, S.

    1976-01-01

    In models of extended hadrons, in which small bits of matter carrying charge and effective mass exist confined within a medium, oscillations in the matter density may occur. A way of investigating this possibility experimentally in high-energy hadron-hadron elastic diffraction scattering is suggested, and the effect is illustrated by examining some existing data which might be relevant to the question [fr

  9. Neutrino Oscillations Physics

    Science.gov (United States)

    Fogli, Gianluigi

    2005-06-01

    We review the status of the neutrino oscillations physics, with a particular emphasis on the present knowledge of the neutrino mass-mixing parameters. We consider first the νμ → ντ flavor transitions of atmospheric neutrinos. It is found that standard oscillations provide the best description of the SK+K2K data, and that the associated mass-mixing parameters are determined at ±1σ (and NDF = 1) as: Δm2 = (2.6 ± 0.4) × 10-3 eV2 and sin 2 2θ = 1.00{ - 0.05}{ + 0.00} . Such indications, presently dominated by SK, could be strengthened by further K2K data. Then we point out that the recent data from the Sudbury Neutrino Observatory, together with other relevant measurements from solar and reactor neutrino experiments, in particular the KamLAND data, convincingly show that the flavor transitions of solar neutrinos are affected by Mikheyev-Smirnov-Wolfenstein (MSW) effects. Finally, we perform an updated analysis of two-family active oscillations of solar and reactor neutrinos in the standard MSW case.

  10. Automation of BESSY scanning tables

    International Nuclear Information System (INIS)

    Hanton, J.; Kesteman, J.

    1981-01-01

    A micro processor M6800 is used for the automation of scanning and premeasuring BESSY tables. The tasks achieved by the micro processor are: 1. control of spooling of the four asynchronous film winding devices and switching on and off the 4 projections lamps, 2. pre-processing of the data coming from a bi-polar coordinates measuring device, 3. bi-directional interchange of informations between the operator, the BESSY table and the DEC PDP 11/34 mini computer controling the scanning operations, 4. control of the magnification on the table by swapping the projection lenses of appropriate focal lengths and the associated light boxes (under development). In connection with point 4, study is being made for the use of BESSY tables for accurate measurements (+/-5 microns), by encoding the displacements of the projections lenses. (orig.)

  11. The Table Mountain Field Site

    Data.gov (United States)

    Federal Laboratory Consortium — The Table Mountain Field Site, located north of Boulder, Colorado, is designated as an area where the magnitude of strong, external signals is restricted (by State...

  12. The redoubtable ecological periodic table

    Science.gov (United States)

    Ecological periodic tables are repositories of reliable information on quantitative, predictably recurring (periodic) habitat–community patterns and their uncertainty, scaling and transferability. Their reliability derives from their grounding in sound ecological principle...

  13. Table 1: Biofuels simulation scenarios

    Data.gov (United States)

    U.S. Environmental Protection Agency — A spreadsheet containing information used to generate Table 1. Agricultural Market sector results presented in the spreadsheet were generated elsewhere (non-EPA) and...

  14. NNDSS - Table I. infrequently reported notifiable diseases

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table I. infrequently reported notifiable diseases - 2016. In this Table, provisional* cases of selected† infrequently reported notifiable diseases...

  15. Culture of microalgae biomass for valorization of table olive processing water; Cultivo de biomasa de microalgas para la valorización del agua de elaboración de las aceitunas de mesa

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, C.G.; Serrano, A.; Ruiz-Filippi, G.; Borja, R.; Fermoso, F.G.

    2016-07-01

    Table olive processing water (TOPW) contains many complex substances, such as phenols, which could be valorized as a substrate for microalgae biomass culture. The aim of this study was to assess the capability of Nannochloropsis gaditana to grow in TOPW at different concentrations (10- 80%) in order to valorize this processing water. Within this range, the highest increment of biomass was determined at percentage of 40% of TOPW, reaching an increment of 0.36 ± 0.05 mg volatile suspended solids (VSS)/L. Components of algal biomass were similar for the experiments at 10-40% of TOPW, where proteins were the major compounds (56-74%). Total phenols were retained in the microalgae biomass (0.020 ± 0.002 g of total phenols/g VSS). Experiments for 80% of TOPW resulted in a low production of microalgae biomass. High organic matter, nitrogen, phosphorus and phenol removal were achieved in all TOPW concentrations. Although high-value products, such as proteins, were obtained and high removal efficiencies of nutrients were determined, microalgae biomass culture should be enhanced to become a suitable integral processing water treatment. [Spanish] El agua resultante del proceso de elaboración de la aceituna de mesa (TOPW) presenta un elevado contenido en sustancias complejas, como fenoles, que podría permitir su uso como sustrato para el cultivo de microalgas. El objetivo de este estudio se centra en evaluar la capacidad de crecimiento de annochloropsis gaditana en TOPW a distintas concentraciones (10-80%) con vistas a la valorización de estas aguas. El mayor incremento de biomasa se obtuvo para un porcentaje del 40% de TOPW, alcanzando un aumento de 0.36 ± 0.50 mg sólidos en suspensión volátiles (SSV)/L. Los componentes presentes en la biomasa han sido similares para los experimentos con 10-40% de TOPW, siendo las proteínas los compuestos mayoritarios en todos los casos (56-74%). Los fenoles totales quedaron retenidos en las microalgas, alcanzando una concentraci

  16. Natural convection heat transfer in an oscillating vertical cylinder.

    Science.gov (United States)

    Khan, Ilyas; Ali Shah, Nehad; Tassaddiq, Asifa; Mustapha, Norzieha; Kechil, Seripah Awang

    2018-01-01

    This paper studies the heat transfer analysis caused due to free convection in a vertically oscillating cylinder. Exact solutions are determined by applying the Laplace and finite Hankel transforms. Expressions for temperature distribution and velocity field corresponding to cosine and sine oscillations are obtained. The solutions that have been obtained for velocity are presented in the forms of transient and post-transient solutions. Moreover, these solutions satisfy both the governing differential equation and all imposed initial and boundary conditions. Numerical computations and graphical illustrations are used in order to study the effects of Prandtl and Grashof numbers on velocity and temperature for various times. The transient solutions for both cosine and sine oscillations are also computed in tables. It is found that, the transient solutions are of considerable interest up to the times t = 15 for cosine oscillations and t = 1.75 for sine oscillations. After these moments, the transient solutions can be neglected and, the fluid moves according with the post-transient solutions.

  17. Enthalpy of sublimation as measured using a silicon oscillator

    Science.gov (United States)

    Shakeel, Hamza; Pomeroy, J. M.

    In this study, we report the enthalpy of sublimation of common gases (nitrogen, oxygen, argon, carbon dioxide, neon, krypton, xenon, and water vapor) using a large area silicon oscillator with a sub-ng (~0.027 ng/cm2) mass sensitivity. The double paddle oscillator design enables high frequency stability (17 ppb) at cryogenic temperatures and provides a consistent technique for enthalpy measurements. The enthalpies of sublimation are derived from the rate of mass loss during programmed thermal desorption and are detected as a change in the resonance frequency of the self-tracking oscillator. These measured enthalpy values show excellent agreement with the accepted literature values.

  18. Some observations on boiling heat transfer with surface oscillation

    International Nuclear Information System (INIS)

    Miyashita, H.

    1992-01-01

    The effects of surface oscillation on pool boiling heat transfer are experimentally studied. Experiments were performed in saturated ethanol and distilled water, covering the range from nucleate to film boiling except in the transition region. Two different geometries were employed as the heating surface with the same wetting area, stainless steel pipe and molybdenum ribbon. The results confirm earlier work on the effect of surface oscillation especially in lower heat flux region of nucleate boiling. Interesting boiling behavior during surface oscillation is observed, which was not referred to in previous work. (2 figures) (Author)

  19. Moderately acurate oscillator strengths from NBS intensities

    International Nuclear Information System (INIS)

    Cowley, C.R.

    1983-01-01

    An earlier paper explored the calibration of NBS Monograph 145 intensity measurements for the purpose of obtaining useful oscillator strengths. In the present work we investigate the question of a single 'temperature' for the copper arc light sources. Statistical arguments support rejection of the null hypothesis of a single temperature. Evidence is found for a mild correction to the intensity scale, but there is no indication that the intensities drift with wave length. We reinforce earlier findings that very useful gf-values can be derived from Monograph 145 intensities for any spectrum in which there are enough accurate measurements for a calibration. For the present, it seems that such calibrations must be made individually for each spectrum, and the predictions should not be extrapolated beyond the calibration domains. A table lists interpolation coefficients for Fe I, Co I, Ni I, Ti I, Zr II, Y II, Nd II and U II. An improved formula is given to transform the Corliss-Tech Fe I oscillator strengths to the Oxford system. (author)

  20. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  1. Mathematical tables tables of in g [z] for complex argument

    CERN Document Server

    Abramov, A A

    1960-01-01

    Mathematical Tables of In ? (z) for Complex Argument is a compilation of tables of In ? (z), z = x + iy, calculated for steps in x and y of 0.01 and with an accuracy of one unit in the last (the sixth) decimal place. Interpolation is used to calculate In ? (z) for intermediate values and is carried out separately for the real and imaginary parts of In ? (z). Six places are retained in interpolation.This book first explains how the values of In ? (z) are calculated using the asymptotic formula in a wide lattice with step h = 0.16, and how the tables and the nomograph are used. The values in the

  2. Quasioptical Josephson oscillator

    International Nuclear Information System (INIS)

    Wengler, M.J.; Pance, A.; Liu, B.

    1991-01-01

    This paper discusses the authors' work with large 2-dimensional arrays of Josephson junctions for submillimeter power generation. The basic design of the Quasioptical Josephson Oscillator (QJO) is presented. The reasons for each design decision are discussed. Superconducting devices have not yet been fabricated, but scale models and computer simulations have been done. A method for characterizing array rf coupling structures is described, and initial results with this method are presented. Microwave scale models of the radiation structure are built and a series of measurements are made with a network analyzer

  3. Modeling microtubule oscillations

    DEFF Research Database (Denmark)

    Jobs, E.; Wolf, D.E.; Flyvbjerg, H.

    1997-01-01

    Synchronization of molecular reactions in a macroscopic volume may cause the volume's physical properties to change dynamically and thus reveal much about the reactions. As an example, experimental time series for so-called microtubule oscillations are analyzed in terms of a minimal model...... for this complex polymerization-depolymerization cycle. The model reproduces well the qualitatively different time series that result from different experimental conditions, and illuminates the role and importance of individual processes in the cycle. Simple experiments are suggested that can further test...... and define the model and the polymer's reaction cycle....

  4. Oscillations in nonlinear systems

    CERN Document Server

    Hale, Jack K

    2015-01-01

    By focusing on ordinary differential equations that contain a small parameter, this concise graduate-level introduction to the theory of nonlinear oscillations provides a unified approach to obtaining periodic solutions to nonautonomous and autonomous differential equations. It also indicates key relationships with other related procedures and probes the consequences of the methods of averaging and integral manifolds.Part I of the text features introductory material, including discussions of matrices, linear systems of differential equations, and stability of solutions of nonlinear systems. Pa

  5. Neutrino oscillations at LAMPF

    International Nuclear Information System (INIS)

    Carlini, R.; Choi, C.; Donohue, J.

    1985-01-01

    Work at Argonne continues on the construction of the neutrino oscillation experiment (E645). Construction of detector supports and active shield components were completed at the Provo plant of the principal contractor for the project (the Pittsburgh-Des Moines Corporation). Erection of the major experimental components was completed at the LAMPF experimental site in mid-March 1985. Work continues on the tunnel which will house the detector. Construction of detector components (scintillators and proportional drift tubes) is proceeding at Ohio State University and Louisiana State University. Consolidation of these components into the 20-ton neutrino detector is beginning at LAMPF

  6. Theory of oscillators

    CERN Document Server

    Andronov, Aleksandr Aleksandrovich; Vitt, Aleksandr Adolfovich

    1966-01-01

    Theory of Oscillators presents the applications and exposition of the qualitative theory of differential equations. This book discusses the idea of a discontinuous transition in a dynamic process. Organized into 11 chapters, this book begins with an overview of the simplest type of oscillatory system in which the motion is described by a linear differential equation. This text then examines the character of the motion of the representative point along the hyperbola. Other chapters consider examples of two basic types of non-linear non-conservative systems, namely, dissipative systems and self-

  7. Solar and stellar oscillations

    International Nuclear Information System (INIS)

    Fossat, E.

    1981-01-01

    We try to explain in simple words what a stellar oscillation is, what kind of restoring forces and excitation mechanisms can be responsible for its occurence, what kind of questions the theoretician asks to the observer and what kind of tools the latter is using to look for the answers. A selected review of the most striking results obtained in the last few years in solar seismology and the present status of their consequences on solar models is presented. A brief discussion on the expected extension towards stellar seismology will end the paper. A selected bibliography on theory as well as observations and recent papers is also included. (orig.)

  8. Coupled nonlinear oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, J; Scott, A C

    1983-01-01

    Topics discussed include transitions in weakly coupled nonlinear oscillators, singularly perturbed delay-differential equations, and chaos in simple laser systems. Papers are presented on truncated Navier-Stokes equations in a two-dimensional torus, on frequency locking in Josephson point contacts, and on soliton excitations in Josephson tunnel junctions. Attention is also given to the nonlinear coupling of radiation pulses to absorbing anharmonic molecular media, to aspects of interrupted coarse-graining in stimulated excitation, and to a statistical analysis of long-term dynamic irregularity in an exactly soluble quantum mechanical model.

  9. Brain Oscillations, Hypnosis, and Hypnotizability.

    Science.gov (United States)

    Jensen, Mark P; Adachi, Tomonori; Hakimian, Shahin

    2015-01-01

    This article summarizes the state-of-science knowledge regarding the associations between hypnosis and brain oscillations. Brain oscillations represent the combined electrical activity of neuronal assemblies, usually measured as specific frequencies representing slower (delta, theta, alpha) and faster (beta, gamma) oscillations. Hypnosis has been most closely linked to power in the theta band and changes in gamma activity. These oscillations are thought to play a critical role in both the recording and recall of declarative memory and emotional limbic circuits. The authors propose that this role may be the mechanistic link between theta (and perhaps gamma) oscillations and hypnosis, specifically, that the increases in theta oscillations and changes in gamma activity observed with hypnosis may underlie some hypnotic responses. If these hypotheses are supported, they have important implications for both understanding the effects of hypnosis and for enhancing response to hypnotic treatments.

  10. Bounded-oscillation Pushdown Automata

    Directory of Open Access Journals (Sweden)

    Pierre Ganty

    2016-09-01

    Full Text Available We present an underapproximation for context-free languages by filtering out runs of the underlying pushdown automaton depending on how the stack height evolves over time. In particular, we assign to each run a number quantifying the oscillating behavior of the stack along the run. We study languages accepted by pushdown automata restricted to k-oscillating runs. We relate oscillation on pushdown automata with a counterpart restriction on context-free grammars. We also provide a way to filter all but the k-oscillating runs from a given PDA by annotating stack symbols with information about the oscillation. Finally, we study closure properties of the defined class of languages and the complexity of the k-emptiness problem asking, given a pushdown automaton P and k >= 0, whether P has a k-oscillating run. We show that, when k is not part of the input, the k-emptiness problem is NLOGSPACE-complete.

  11. Single ICCII Sinusoidal Oscillators Employing Grounded Capacitors

    Directory of Open Access Journals (Sweden)

    J. W. Horng

    2011-09-01

    Full Text Available Two inverting second-generation current conveyors (ICCII based sinusoidal oscillators are presented. The first sinusoidal oscillator is composed of one ICCII, two grounded capacitors and two resistors. The oscillation condition and oscillation frequency can be orthogonally controllable. The second sinusoidal oscillator is composed of one ICCII, two grounded capacitors and three resistors. The oscillation condition and oscillation frequency can be independently controllable through different resistors.

  12. Solution of the Schrodinger Equation for a Diatomic Oscillator Using Linear Algebra: An Undergraduate Computational Experiment

    Science.gov (United States)

    Gasyna, Zbigniew L.

    2008-01-01

    Computational experiment is proposed in which a linear algebra method is applied to the solution of the Schrodinger equation for a diatomic oscillator. Calculations of the vibration-rotation spectrum for the HCl molecule are presented and the results show excellent agreement with experimental data. (Contains 1 table and 1 figure.)

  13. Stable And Oscillating Acoustic Levitation

    Science.gov (United States)

    Barmatz, Martin B.; Garrett, Steven L.

    1988-01-01

    Sample stability or instability determined by levitating frequency. Degree of oscillation of acoustically levitated object along axis of levitation chamber controlled by varying frequency of acoustic driver for axis above or below frequency of corresponding chamber resonance. Stabilization/oscillation technique applied in normal Earth gravity, or in absence of gravity to bring object quickly to rest at nominal levitation position or make object oscillate in desired range about that position.

  14. Isotropic oscillator: spheroidal wave functions

    International Nuclear Information System (INIS)

    Mardoyan, L.G.; Pogosyan, G.S.; Ter-Antonyan, V.M.; Sisakyan, A.N.

    1985-01-01

    Solutions of the Schroedinger equation are found for an isotropic oscillator (10) in prolate and oblate spheroidal coordinates. It is shown that the obtained solutions turn into spherical and cylindrical bases of the isotropic oscillator at R→0 and R→ infinity (R is the dimensional parameter entering into the definition of prolate and oblate spheroidal coordinates). The explicit form is given for both prolate and oblate basis of the isotropic oscillator for the lowest quantum states

  15. Neutrino oscillations. Theory and experiment

    International Nuclear Information System (INIS)

    Beshtoev, Kh.M.

    2001-01-01

    Theoretical schemes on neutrino oscillations are considered. The experimental data on neutrino oscillations obtained in the Super-Kamiokande (Japan) and SNO (Canada) experiments are given. Comparison of these data with the predictions obtained in the theoretical schemes is done. Conclusion is made that the experimental data confirm only the scheme with transitions (oscillations) between aromatic ν e -, ν μ -, ν τ - neutrinos with maximal angle mixings. (author)

  16. Monthly tables of measurements. October 2000; Tableaux mensuels des mesures. Octobre 2000

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-01

    This report of the O.P.R.I. (Office of Protection against Ionizing Radiations) exposes the principal results concerning the routine monitoring of environmental radioactivity in France: atmospheric dusts, rainwater, surface water, underground water, sewage water, drinking water, food chain (milk, vegetables, fishes), sea water around nuclear sites and other sites. The activities of various radioisotopes are presented in tables. (N.C.)

  17. Chemotaxis and Actin Oscillations

    Science.gov (United States)

    Bodenschatz, Eberhard; Hsu, Hsin-Fang; Negrete, Jose; Beta, Carsten; Pumir, Alain; Gholami, Azam; Tarantola, Marco; Westendorf, Christian; Zykov, Vladimir

    Recently, self-oscillations of the cytoskeletal actin have been observed in Dictyostelium, a model system for studying chemotaxis. Here we report experimental results on the self-oscillation mechanism and the role of regulatory proteins and myosin II. We stimulate cells rapidly and periodically by using photo un-caging of the chemoattractant in a micro-fluidic device and measured the cellular responses. We found that the response amplitude grows with stimulation strength only in a very narrow region of stimulation, after which the response amplitude reaches a plateau. Moreover, the frequency-response is not constant but rather varies with the strength of external stimuli. To understand the underlying mechanism, we analyzed the polymerization and de-polymerization time in the single cell level. Despite of the large cell-to-cell variability, we found that the polymerization time is independent of external stimuli and the de-polymerization time is prolonged as the stimulation strength increases. Our conclusions will be summarized and the role of noise in the signaling network will be discussed. German Science Foundation CRC 937.

  18. The Wien Bridge Oscillator Family

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2006-01-01

    A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic of the ampli......A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic...

  19. Unstable oscillators based hyperchaotic circuit

    DEFF Research Database (Denmark)

    Murali, K.; Tamasevicius, A.; G. Mykolaitis, A.

    1999-01-01

    A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations in the circ...... in the circuit. The performance of the circuit is investigated by means of numerical integration of appropriate differential equations, PSPICE simulations, and hardware experiment.......A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations...

  20. Heat exchanger with oscillating flow

    Science.gov (United States)

    Scotti, Stephen J. (Inventor); Blosser, Max L. (Inventor); Camarda, Charles J. (Inventor)

    1993-01-01

    Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

  1. Characteristics of Tables for Disseminating Biobehavioral Results.

    Science.gov (United States)

    Schneider, Barbara St Pierre; Nagelhout, Ed; Feng, Du

    2018-01-01

    To report the complexity and richness of study variables within biological nursing research, authors often use tables; however, the ease with which consumers understand, synthesize, evaluate, and build upon findings depends partly upon table design. To assess and compare table characteristics within research and review articles published in Biological Research for Nursing and Nursing Research. A total of 10 elements in tables from 48 biobehavioral or biological research or review articles were analyzed. To test six hypotheses, a two-level hierarchical linear model was used for each of the continuous table elements, and a two-level hierarchical generalized linear model was used for each of the categorical table elements. Additionally, the inclusion of probability values in statistical tables was examined. The mean number of tables per article was 3. Tables in research articles were more likely to contain quantitative content, while tables in review articles were more likely to contain both quantitative and qualitative content. Tables in research articles had a greater number of rows, columns, and column-heading levels than tables in review articles. More than one half of statistical tables in research articles had a separate probability column or had probability values within the table, whereas approximately one fourth had probability notes. Authors and journal editorial staff may be generating tables that better depict biobehavioral content than those identified in specific style guidelines. However, authors and journal editorial staff may want to consider table design in terms of audience, including alternative visual displays.

  2. 30 CFR 250.1401 - Index table.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Index table. 250.1401 Section 250.1401 Mineral... OPERATIONS IN THE OUTER CONTINENTAL SHELF Outer Continental Shelf (OCS) Civil Penalties § 250.1401 Index table. The following table is an index of the sections in this subpart: § 250.1401Table Definitions...

  3. Oscillator strengths and radiative rates for transitions in neutral sulfur

    International Nuclear Information System (INIS)

    Deb, N.C.; Hibbert, A.

    2008-01-01

    We present accurate oscillator strengths and radiative rates for 2173 E1 transitions among the 120 levels belonging to 3s 2 3p 4 , 3s3p 5 , and 3s 2 3p 3 ( 4 S o , 2 D o , 2 P o )nl configurations where nl=4s,5s,6s,4p,5p,6p,3d,4d,4f,5f. A configuration interaction approach is employed through the standard CIV3 program. The 114 LS states included in the present calculation generate 250 fine-structure levels belonging to the above configurations below 100,000 cm -1 . However, results of only 120 fine-structure levels are presented due to the absence of experimental energy values for the remaining levels. Tabulations of oscillator strengths and radiative rates, and their comparison with other calculations, are presented in the first two tables. In a separate table the oscillator strengths and transition probabilities, in length and velocity gauges, are presented for 2173 E1 transitions, and are arranged in ascending order of wavelength

  4. The Alfonsine tables of Toledo

    CERN Document Server

    Chabás, José

    2003-01-01

    The Alfonsine Tables of Toledo is for historians working in the fields of astronomy, science, the Middle Ages, Spanish and other Romance languages. It is also of interest to scholars interested in the history of Castile, in Castilian-French relations in the Middle Ages and in the history of patronage. It explores the Castilian canons of the Alfonsine Tables and offers a study of their context, language, astronomical content, and diffusion. The Alfonsine Tables of Toledo is unique in that it: includes an edition of a crucial text in history of science; provides an explanation of astronomy as it was practiced in the Middle Ages; presents abundant material on early scientific language in Castilian; presents new material on the diffusion of Alfonsine astronomy in Europe; describes the role of royal patronage of science in a medieval context.

  5. Effect of non-condensation gas on pressure oscillation of submerged steam jet condensation

    International Nuclear Information System (INIS)

    Zhao, Quanbin; Cong, Yuelei; Wang, Yingchun; Chen, Weixiong; Chong, Daotong; Yan, Junjie

    2016-01-01

    Highlights: • Oscillation intensity of steam–air jet increases with rise of water temperature. • Oscillation intensity reduces obviously when air is mixed. • Both first and second dominant frequencies decrease with rise of air mass fraction. • Air has little effect on power of 1st & 2nd frequency bands under low temperature. • The maximum oscillation power occurs under case of A = 1% and T ⩾ 50 °C. - Abstract: The effect of air with low mass fraction on the oscillation intensity and oscillation frequency of a submerged steam jet condensation is investigated under stable condensation region. With air mixing in steam, an obvious dynamic pressure peak appears along the jet direction. The intensity peak increases monotonously with the rise of steam mass flux and water temperature. Peak position moves downstream with the rise of air mass fraction. Moreover, when compared with that of pure steam jet, the oscillation intensity clearly decreases as air is mixed. However, when water temperature is lower than approximately 45 °C, oscillation intensity increases slightly with the rise of air mass fraction, and when water temperature is higher than 55 °C, the oscillation intensity decreases greatly with the rise of air mass fraction. Both the first and second dominant frequencies decrease with rise of air mass fraction. Finally, effect of air mass fractions on the oscillation power of the first and second dominant frequency bands shows similar trends. Under low water temperature, the mixed air has little effect on the oscillation power of both first and second frequency bands. However, when water temperature is high, the oscillation power of both first and second frequency bands appears an obvious peak when air mass fraction is about 1%. With further rise of air mass fraction, the oscillation power decreases gradually.

  6. Oyster Creek fuel thermal margin during core thermal-hydraulic oscillations

    International Nuclear Information System (INIS)

    Dougher, J.D.

    1990-01-01

    The Oyster Creek nuclear facility, a boiling water reactor (BWR)-2 plant type, has never experienced core thermal-hydraulic instability. Power oscillations, however, have been observed in other BWR cores both domestically and internationally. Two modes of oscillations have been observed, core wide and regional half-core. During core wide oscillations, the neutron flux in the core oscillates in the radial fundamental mode. During regional half-core oscillations, higher order harmonics in the radial plane result in out-of-phase oscillations with the neutron flux in one half of the core oscillating 180 deg out-of-phase with the neutron flux in the other half of the core. General Design Criteria 12 requires either prevention or detection and suppression of power oscillations which could result in violations of fuel design limits. Analyses performed by General Electric have demonstrated that for large-magnitude oscillations the potential exists for violation of the safety limit minimum critical power ratio (MCPR). However, for plants with a flow-biased neutron flux scram automatic mitigation of oscillations may be provided at an oscillation magnitude below that at which the safety limit is challenged. Plant-specific analysis for Oyster Creek demonstrates that the existing average power range monitor (APRM) system will sense and suppress power oscillations prior to violation of any safety limits

  7. Statistical probability tables CALENDF program

    International Nuclear Information System (INIS)

    Ribon, P.

    1989-01-01

    The purpose of the probability tables is: - to obtain dense data representation - to calculate integrals by quadratures. They are mainly used in the USA for calculations by Monte Carlo and in the USSR and Europe for self-shielding calculations by the sub-group method. The moment probability tables, in addition to providing a more substantial mathematical basis and calculation methods, are adapted for condensation and mixture calculations, which are the crucial operations for reactor physics specialists. However, their extension is limited by the statistical hypothesis they imply. Efforts are being made to remove this obstacle, at the cost, it must be said, of greater complexity

  8. Multidecadal oscillations in rainfall and hydrological extremes

    Science.gov (United States)

    Willems, Patrick

    2013-04-01

    Many studies have anticipated a worldwide increase in the frequency and intensity of precipitation extremes and floods since the last decade(s). Natural variability by climate oscillations partly determines the observed evolution of precipitation extremes. Based on a technique for the identification and analysis of changes in extreme quantiles, it is shown that hydrological extremes have oscillatory behaviour at multidecadal time scales. Results are based on nearly independent extremes extracted from long-term historical time series of precipitation intensities and river flows. Study regions include Belgium - The Netherlands (Meuse basin), Ethiopia (Blue Nile basin) and Ecuador (Paute basin). For Belgium - The Netherlands, the past 100 years showed larger and more hydrological extremes around the 1910s, 1950-1960s, and more recently during the 1990-2000s. Interestingly, the oscillations for southwestern Europe are anti-correlated with these of northwestern Europe, thus with oscillation highs in the 1930-1940s and 1970s. The precipitation oscillation peaks are explained by persistence in atmospheric circulation patterns over the North Atlantic during periods of 10 to 15 years. References: Ntegeka V., Willems P. (2008), 'Trends and multidecadal oscillations in rainfall extremes, based on a more than 100 years time series of 10 minutes rainfall intensities at Uccle, Belgium', Water Resources Research, 44, W07402, doi:10.1029/2007WR006471 Mora, D., Willems, P. (2012), 'Decadal oscillations in rainfall and air temperature in the Paute River Basin - Southern Andes of Ecuador', Theoretical and Applied Climatology, 108(1), 267-282, doi:0.1007/s00704-011-0527-4 Taye, M.T., Willems, P. (2011). 'Influence of climate variability on representative QDF predictions of the upper Blue Nile Basin', Journal of Hydrology, 411, 355-365, doi:10.1016/j.jhydrol.2011.10.019 Taye, M.T., Willems, P. (2012). 'Temporal variability of hydro-climatic extremes in the Blue Nile basin', Water

  9. Limit cycle analysis of nuclear coupled density wave oscillations

    International Nuclear Information System (INIS)

    Ward, M.E.

    1985-01-01

    An investigation of limit cycle behavior for the nuclear-coupled density wave oscillation (NCDWO) in a boiling water reactor (BWR) was performed. A simplified nonlinear model of BWR core behavior was developed using a two-region flow channel representation, coupled with a form of the point-kinetics equation. This model has been used to investigate the behavior of large amplitude NCDWO's through conventional time-integration solutions and through application of a direct relaxation-oscillation limit cycle solution in phase space. The numerical solutions demonstrate the potential for severe global power and flow oscillations in a BWR core at off-normal conditions, such as might occur during Anticipated Transients without Scram. Because of the many simplifying assumptions used, it is felt that the results should not be interpreted as an absolute prediction of core behavior, but as an indication of the potential for large oscillations and a demonstration of the corresponding limit cycle mechanisms. The oscillations in channel density drive the core power variations, and are reinforced by heat flux variations due to the changing fuel temperature. A global temperature increase occurs as energy is accumulated in the fuel, and limits the magnitude of the oscillations because as the average channel density decreases, the amplitude and duration of positive void reactivity at a given oscillation amplitude is lessened

  10. Reactor oscillator - I - III, Part I

    International Nuclear Information System (INIS)

    Lolic, B.

    1961-12-01

    Project 'Reactor oscillator' covers the following activities: designing reactor oscillators for reactors RA and RB with detailed engineering drawings; constructing and mounting of the oscillator; designing and constructing the appropriate electronic equipment for the oscillator; measurements at the RA and RB reactors needed for completing the oscillator construction

  11. Time domain oscillating poles: Stability redefined in Memristor based Wien-oscillators

    KAUST Repository

    Talukdar, Abdul Hafiz Ibne; Radwan, Ahmed G.; Salama, Khaled N.

    2012-01-01

    poles. The idea is verified using a Memristor based Wien oscillator. Sustained oscillations are observed without having the poles of the system fixed on the imaginary axis and the oscillating behavior of the system poles is reported. The oscillating

  12. Damping of Coherent oscillations

    CERN Document Server

    Vos, L

    1996-01-01

    Damping of coherent oscillations by feedback is straightforward in principle. It has been a vital ingredient for the safe operation of accelerators since a long time. The increasing dimensions and beam intensities of the new generation of hadron colliders impose unprecedented demands on the performance of future systems. The arguments leading to the specification of a transverse feedback system for the CERN SPS in its role as LHC injector and the LHC collider itself are developped to illustrate this. The preservation of the transverse emittance is the guiding principle during this exercise keeping in mind the hostile environment which comprises: transverse impedance bent on developping coupled bunch instabilities, injection errors, unwanted transverse excitation, unavoidable tune spreads and noise in the damping loop.

  13. Convection and stellar oscillations

    DEFF Research Database (Denmark)

    Aarslev, Magnus Johan

    2017-01-01

    for asteroseismology, because of the challenges inherent in modelling turbulent convection in 1D stellar models. As a result of oversimplifying the physics near the surface, theoretical calculations systematically overestimate the oscillation frequencies. This has become known as the asteroseismic surface effect. Due...... to lacking better options, this frequency difference is typically corrected for with ad-hoc formulae. The topic of this thesis is the improvement of 1D stellar convection models and the effects this has on asteroseismic properties. The source of improvements is 3D simulations of radiation...... atmospheres to replace the outer layers of stellar models. The additional turbulent pressure and asymmetrical opacity effects in the atmosphere model, compared to convection in stellar evolution models, serve to expand the atmosphere. The enlarged acoustic cavity lowers the pulsation frequencies bringing them...

  14. Photospheric oscillations. Pt. 1

    International Nuclear Information System (INIS)

    Fossat, E.; Ricort, G.

    1975-01-01

    Intensity fluctuations in the wings of the Fraunhofer line Na D 1 5896 have been recorded for about two hundred hours at the focus of the Nice coude refractor, using a sodium optical resonance device. Because of the large beam aperture available, records have been made on circular apertures from 22'' up to 32' diameter (the whole sun). The principal results from the analysis of these date are: As shown by White and Cha, the five-minute oscillation has a gaussian random character with a mean lifetime of about 20 min. Its two-dimensional spatial power spectrum is roughly gaussian for every temporal frequency between 2 and 6 MHz. The width of this gaussian spectrum is near 5 x 10 -5 km -1 (i.e. π = 20,000 km). (orig./BJ) [de

  15. Coronal Waves and Oscillations

    Directory of Open Access Journals (Sweden)

    Nakariakov Valery M.

    2005-07-01

    Full Text Available Wave and oscillatory activity of the solar corona is confidently observed with modern imaging and spectral instruments in the visible light, EUV, X-ray and radio bands, and interpreted in terms of magnetohydrodynamic (MHD wave theory. The review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves, theoretical modelling of interaction of MHD waves with plasma structures, and implementation of the theoretical results for the mode identification. Also the use of MHD waves for remote diagnostics of coronal plasma - MHD coronal seismology - is discussed and the applicability of this method for the estimation of coronal magnetic field, transport coefficients, fine structuring and heating function is demonstrated.

  16. Oscillator strengths for neutral technetium

    International Nuclear Information System (INIS)

    Garstang, R.H.

    1981-01-01

    Oscillator strengths have been calculated for most of the spectral lines of TcI which are of interest in the study of stars of spectral type S. Oscillator strengths have been computed for the corresponding transitions in MnI as a partial check of the technetium calculations

  17. Hyperchaos in coupled Colpitts oscillators

    DEFF Research Database (Denmark)

    Cenys, Antanas; Tamasevicius, Arunas; Baziliauskas, Antanas

    2003-01-01

    The paper suggests a simple solution of building a hyperchaotic oscillator. Two chaotic Colpitts oscillators, either identical or non-identical ones are coupled by means of two linear resistors R-k. The hyperchaotic output signal v(t) is a linear combination, specifically the mean of the individual...

  18. Stochastic and Chaotic Relaxation Oscillations

    NARCIS (Netherlands)

    Grasman, J.; Roerdink, J.B.T.M.

    1988-01-01

    For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a

  19. Oscillating solitons in nonlinear optics

    Indian Academy of Sciences (India)

    ... are derived, and the relevant properties and features of oscillating solitons are illustrated. Oscillating solitons are controlled by the reciprocal of the group velocity and Kerr nonlinearity. Results of this paper will be valuable to the study of dispersion-managed optical communication system and mode-locked fibre lasers.

  20. Augmenting cognition by neuronal oscillations

    NARCIS (Netherlands)

    Horschig, J.M.; Zumer, J.; Bahramisharif, A.

    2014-01-01

    Cortical oscillations have been shown to represent fundamental functions of a working brain, e.g., communication, stimulus binding, error monitoring, and inhibition, and are directly linked to behavior. Recent studies intervening with these oscillations have demonstrated effective modulation of both