WorldWideScience
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Water-level fluctuations affect macrophyte richness in floodplain lakes  

OpenAIRE

The characteristic ecology of floodplain lakes is in part due to their relatively strong water-level fluctuations. We analyzed the factors determining water-level fluctuations in 100 floodplain lakes (during non-flooded conditions) in the active floodplains of the Lower Rhine in the Netherlands. Furthermore, we explored the relationship between water-level fluctuations and macrophyte species richness, and analyzed the suitability of artificially created lakes for macrophyte vegetation. During...

Geest, G. J.; Wolters, H.; Roozen, F. C. J. M.; Coops, H.; Roijackers, R. M. M.; Buijse, A. D.; Scheffer, M.

2005-01-01

2

Reverse water level fluctuations in semiconfined aquifer systems — ``rhade effect''  

Science.gov (United States)

Pumping tests in semiconfined aquifer systems near Dorsten (F.R.G.) caused anomalous reverse water level fluctuations in observation wells tapping the overlying confining bed (aquitard) at different depths (multilevel piezometer). Whenever water is pumped from a well that is screened in the aquifer of the "Halterner Sande", the piezometric surface in the aquitard ("Bottroper Mergel") rises. After that increase, the water level falls according to the drawdown of head within the pumped aquifer (Noordbergum effect according to Verruijt, 1969). Conversely, the piezometric surface in the aquitard falls whenever the pump is shut off (Rhade effect). The anomalous water level reactions propagate with decreasing amplitude from the aquifer-aquitard boundary to the top of the semipermeable layer. Such water level fluctuations ("swelling effects") may be explained by the capability of a water-saturated, compacted material to change volume when subjected to sudden pressure changes. On a practical basis, the Noordbergum and Rhade effects must be taken into consideration for evaluating long-term changes in chemical and hydraulic properties in pumped, semiconfined aquifer systems.

Langguth, H. R.; Treskatis, C.

1989-07-01

3

Reverse water-level fluctuations associated with fracture connectivity.  

Science.gov (United States)

Reverse water-level fluctuations (RWFs), a phenomenon in which water levels rise briefly in response to pumping, were detected in monitoring wells in a fractured siliciclastic aquifer system near a deep public supply well. The magnitude and timing of RWFs provide important information that can help interpret aquifer hydraulics near pumping wells. A RWF in a well is normally attributed to poroelastic coupling between the solid and fluid components in an aquifer system. In addition to revealing classical pumping-induced poroelastic RWFs, data from pressure transducers located at varying depths and distances from the public supply well suggest that the RWFs propagate rapidly through fractures to influence wells hundreds of meters from the pumping well. The rate and cycling frequency of pumping is an important factor in the magnitude of RWFs. The pattern of RWF propagation can be used to better define fracture connectivity in an aquifer system. Rapid, cyclic head changes due to RWFs may also serve as a mechanism for contaminant transport. PMID:23473020

Gellasch, Christopher A; Wang, Herbert F; Bradbury, Kenneth R; Bahr, Jean M; Lande, Lauren L

2014-01-01

4

Analysis of environmental issues related to small-scale hydroelectric development. III. Water level fluctuation  

Energy Technology Data Exchange (ETDEWEB)

Potential environmental impacts in reservoirs and downstream river reaches below dams that may be caused by the water level fluctuation resulting from development and operation of small scale (under 25MW) hydroelectric projects are identified. The impacts discussed will be of potential concern at only those small-scale hydroelectric projects that are operated in a store and release (peaking) mode. Potential impacts on physical and chemical characteristics in reservoirs resulting from water level fluctuation include resuspension and redistribution of bank and bed sediment; leaching of soluble organic matter from sediment in the littoral zone; and changes in water quality resulting from changes in sediment and nutrient trap efficiency. Potential impacts on reservoir biota as a result of water level fluctuation include habitat destruction and the resulting partial or total loss of aquatic species; changes in habitat quality, which result in reduced standing crop and production of aquatic biota; and possible shifts in species diversity. The potential physical effects of water level fluctuation on downstream systems below dams are streambed and bank erosion and water quality problems related to resuspension and redistribution of these materials. Potential biological impacts of water level fluctuation on downstream systems below dams result from changes in current velocity, habitat reduction, and alteration in food supply. These alterations, either singly or in combination, can adversely affect aquatic populations below dams. The nature and potential significance of adverse impacts resulting from water level fluctuation are discussed. Recommendations for site-specific evaluation of water level fluctuation at small-scale hydroelectric projects are presented.

Hildebrand, S.G. (ed.)

1980-10-01

5

Water-level Fluctuations in the Eberswalde crater (Mars)  

Science.gov (United States)

The Eberswalde crater represents a spectacularly exposed example of water-related activity on Mars past geological history [1,2,3,4,5,6,7]. Eberswalde Crater at about 24.9° S., 33.7° W., lies just NE of Holden Crater and Uzboi Valles in Margaritifer Terra, Mars. We investigated the geology of this crater using MOC NA and HRSC imagery in combination with MOLA and HRSC derived DTM in order to recognize water-related processes and to infer depositional environments and depositional architecture. The fan delta located in the easternmost part of the crater presents well developed morphologies [1,2,3,4,5,6,7]. It consists of five lobes, suggesting prevalence of input related processes [4], even if wave- related processes seem to have been present as well [7]. Some of these lobes are coeval with the emplacement of synsedimentary tectonics and their morphology appears at least partly structural-controlled. The delta is made of bright and dark interlayered deposits. Some of the bright layers consist of very poorly sorted material, with boulders up to 10 meters of diameter floating in a finer matrix suggesting an emplacement as mass flows. Other layers consist of finer and better-sorted material. Most of the lobes display a low-dipping proximal area (1°-2°), a distal high-dipping area (6°-10°) and a more distal low-dipping area (1°-2°). We interpret the low dipping proximal part as delta plain consisting of distributary areas, mostly built by coalescing point bars [4,5], and interdistributary areas, in which crevasse splays flooded into the plain [7]. At places the topset-foreset-bottomset architecture typical of fan delta is present. In other cases, friction-related processes appear to be dominant. We interpret the high-dipping part of the fan delta as delta front deposits [7]. The oldest lobe display a transgressive-regressive cycle with a retrogradational stacking pattern at the base on top of which progradation develops. We interpret the retrogradational stacking pattern as formed during a Transgressive System Tract and the progradational stacking pattern related to a HighStand System Tract. The transition among these systems is marked by a Maximum Flooding Surface. A change in the morphology of the distributary channels from meandering to braided associated with a distal shift of the system appear to be related to a drop of the water level depicting a forced regression scenario. We interpret this lobe as formed during a Falling Stage System Tract. Friction-related processes appear to be dominant in this shallow-water type fan delta. The following lobe was deposited during another phase of rising water table which displays an overall aggradational stacking pattern [6,7] suggesting a certain equilibrium between sedimentary input, tectonic subsidence and level of the water table. The youngest two lobes do not display such a well developed depositional architecture, suggesting more episodic sedimentary activity. References 1. Malin, and Edgett, Science, 302, 1931-1934, 2003.2. Moore et al., Geophys. Res. Lett., 30, 24, 2292, doi: 10.1029/2003GL019002, 2003.3. Jerolmack et al., Geophys. Res. Lett., 31, L21701, doi: 10.1029/2004GL021326, 2004.4. Bhattacharya et al., Geophys. Res. Lett., 32, L10201, doi: 10.1029/2005GL022747, 2005.5. Wood, GSA Bulletin, 118, 5-6, 557-566; doi: 10.1130/B25822.1, 2006.6. Lewis and Aharanson, J. Geophys. Res., 111, E06001, doi: 10.1029/2005JE002558, 2006.7. Pondrelli et al., LPSC XXXVII, abstract 1555, 2006.

Pondrelli, M.; Rossi, A. P.; Marinangeli, L.; Hauber, E.; Baliva, A.; Gwinner, K.

2006-12-01

6

Assessment of impacts from water level fluctuations on fish in the Hanford Reach, Columbia River  

Energy Technology Data Exchange (ETDEWEB)

Observations on the effects of water level fluctuations in the Hanford Reach of the Columbia River, Washington, were made in 1976 and 1977. The two years provided contrasting flow regimes: high water and fluctuations of greater magnitude prevailed in 1976; low water and higher temperatures prevailed in 1977. Situations where fish and other aquatic organisms were destroyed by changing water levels were observed and evaluated each year in three study areas: Hanford, F-Area, and White Bluffs sloughs. Losses primarily were due to stranding, entrapment (with or without complete dewatering), and predation. Juvenile fish were more susceptible to entrapment and stranding than were adult fish. Estimates of actual losses were biased and conservative because relatively few fish could be found after each decline of water level and dewatering. The most valued species of fish affected by water level fluctuations at Hanford were the anadromus fall chinook salmon (Oncorhynchus tshawytscha) and the resident smallmouth bass (Micropterus dolomieui). Crucial periods for chinook salmon occurred during winter when incubating eggs were in the gravel of the main channel, and before and during seaward migration in the spring when fry were abundant in shoreline zones. The crucial period for smallmouth bass was during spring and early summer when adults were spawning in warmed sloughs and shoreline zones. Chinook salmon and smallmouth bass fry were vulnerable to stranding and entrapment, and smallmouth bass nests were susceptible to exposure and temperature changes resulting from repeated water level fluctuations. Thus, flow manipulation may be crucial to their survival. The extent to which other species of riverine fish were affected by water level fluctuations depended upon their use of shoreline zones for spawning and rearing young.

Becker, C.D.; Fickeisen, D.H.; Montgomery, J.C.

1981-05-01

7

Pleiades and radar imagery in tracking water level fluctuations in reservoirs  

OpenAIRE

Tracking water level fluctuations is important to the study and management of waterbodies. A geographic object-based image analysis using very high spatial and temporal radar interferometry (Cosmo-Skymed and TerraSAR-X) and optical (Pléiades) imagery is adopted in this study for this purpose. A linear regression model was sufficient to correlate the water surface area of a mildly sloping and unencumbered littoral zone spatial subset (extracted from 14 images) to water surface altitude data f...

Simon, R. N.; Tormos, T.; Danis, P. A.

2014-01-01

8

A Hydro-Economic Model for Water Level Fluctuations: Combining Limnology with Economics for Sustainable Development of Hydropower  

OpenAIRE

Water level fluctuations in lakes lead to shoreline displacement. The seasonality of flooding or beaching of the littoral area affects nutrient cycling, redox gradients in sediments, and life cycles of aquatic organisms. Despite the ecological importance of water level fluctuations, we still lack a method that assesses water levels in the context of hydropower operations. Water levels in reservoirs are influenced by the operator of a hydropower plant, who discharges water through the turbines...

Hirsch, Philipp Emanuel; Schillinger, Sebastian; Weigt, Hannes; Burkhardt-holm, Patricia

2014-01-01

9

Earthquake-induced water-level fluctuations at Yucca Mountain, Nevada, June 1992  

International Nuclear Information System (INIS)

This report presents earthquake-induced water-level and fluid-pressure data for wells in the Yucca Mountain area, Nevada, during June 1992. Three earthquakes occurred which caused significant water-level and fluid-pressure responses in wells. Wells USW H-5 and USW H-6 are continuously monitored to detect short-term responses caused by earthquakes. Two wells, monitored hourly, had significant, longer-term responses in water level following the earthquakes. On June 28, 1992, a 7.5-magnitude earthquake occurred near Landers, California causing an estimated maximum water-level change of 90 centimeters in well USW H-5. Three hours later a 6.6-magnitude earthquake occurred near Big Bear Lake, California; the maximum water-level fluctuation was 20 centimeters in well USW H-5. A 5.6-magnitude earthquake occurred at Little Skull Mountain, Nevada, on June 29, approximately 23 kilometers from Yucca Mountain. The maximum estimated short-term water-level fluctuation from the Little Skull Mountain earthquake was 40 centimeters in well USW H-5. The water level in well UE-25p number-sign 1, monitored hourly, decreased approximately 50 centimeters over 3 days following the Little Skull Mountain earthquake. The water level in UE-25p number-sign 1 returned to pre-earthquake levels in approximately 6 months. The water level in the lower interval of well USW H-3 increased 28 centimeters following the Little Skull Mountain earthquake. The Landers and Little Skull Mountain earthquakes caused responses in 17 intervals of 14 hourly monitored wells, however, most responses were small and of short duration. For several days following the major earthquakes, many smaller magnitude aftershocks occurred causing measurable responses in the continuously monitored wells

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Measuring Water Level Fluctuations of two Connected Wetlands in the Dominican Republic Using InSAR  

Science.gov (United States)

Wetlands are ecosystems of high endemism and great biodiversity. Using the double-reflected radar waves off the water surface and trunks of inundated vegetation, Interferometric Synthetic Aperture Radar (InSAR) is capable of measuring water level fluctuations from space at a cm-level accuracy in these ecosystems with emergent vegetation. InSAR can provide a high spatial resolution over a large area that the more traditional terrestrial-based methods lack. In this study, we applied InSAR to study the seasonal variations in water level of the wetlands near two lakes in the southwest of the Dominican Republic: Lake Enriquillo, a highly saline lake designated as a Wetland of International Importance under the Ramsar Convention in 2002, and Laguna del Limon. Both lake-wetland systems are located in the Jaragua-Bahoruco-Enriquillo Biosphere Reserve. Since 2003 the water level of Lake Enriquillo has increased drastically and caused the evacuation of many farmers from nearby villages. Lake level changes also affected the habitats of several native and migratory species. We used the data acquired by the Phased Array type L-band Synthetic Aperture Radar (PALSAR) sensor on board of the Japanese Advanced Land Observation Satellite (ALOS) from October 2008 to January 2011. For the smaller lake, Laguna del Limon, we found a seasonal variation of 10-15 centimeters. This result was confirmed using two different satellite paths. For Lake Enriquillo we found a net decrease of about 20 centimeters in the water level from September 2009 to January 2011. This result agrees with an independent estimation based on lake hydrodynamics model predictions. In addition, our InSAR-based time series of lake level fluctuations revealed distinct behaviors of the two wetlands. For the Lake Enriquillo we found a continuous decrease in the water level throughout 2010 with a brief increase of the water level during the summer months, while for Laguna del Limon during the summer months the water level decreased and the lake presented a net increase in the water level. The decrease in water level for Lake Enriquillo can be explained by the reduce precipitation rate in 2010 compared to previous years. We demonstrate that InSAR is an effective way to measure water level fluctuations at wetlands in this region. The same method could be applied to other wetlands in the area to fully understand the complex hydrology of the connected wetland systems and the impacts of the hydrological changes on the environment and local human community.

Pichardo Marcano, M. D.; Liu, L.; Zebker, H. A.

2012-12-01

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Establishment of earth tides effect on water level fluctuations in an unconfined hard rock aquifer using spectral analysis  

CERN Document Server

Short-interval water level measurements using automatic water level recorder in a deep well in an unconfined crystalline rock aquifer at the campus of NGRI, near Hyderabad shows a cyclic fluctuation in the water levels. The observed values clearly show the principal trend due to rainfall recharge. Spectral analysis was carried out to evaluate correlation of the cyclic fluctuation to the synthetic earth tides as well as groundwater withdrawal time series in the surrounding. It was found that these fluctuations have considerably high correlation with earth tides whereas groundwater pumping does not show any significant correlation with water table fluctuations. It is concluded that earth tides cause the fluctuation in the water table. These fluctuations were hitherto unobserved during manual observations made over larger time intervals. It indicates that the unconfined aquifer is characterised by a low porosity.

Maréchal, Jean-Christophe; Ahmed, Shakeel; Lachassagne, Patrick

2010-01-01

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Response of littoral macrophytes to water level fluctuations in a storage reservoir  

Directory of Open Access Journals (Sweden)

Full Text Available Lakes and reservoirs that are used for water supply and/or flow regulations have usually poorly developed littoral macrophyte communities, which impairs ecological potential in terms of the EU Water Framework Directive. The aim of our study was to reveal controlling factors for the growth of littoral macrophytes in a storage reservoir with fluctuating water level (Lipno Reservoir, Czech Republic. Macrophytes occurred in this reservoir only in the eulittoral zone i.e., the shoreline region between the highest and the lowest seasonal water levels. Three eulittoral sub-zones could be distinguished: the upper eulittoral with a stable community of perennial species with high cover, the middle eulittoral with relatively high richness of emergent and amphibious species present at low cover values, and the lower eulittoral devoid of permanent vegetation. Cover and species composition in particular sub-zones were primarily influenced by the duration and timing of flooding, followed by nutrient limitation and strongly reducing conditions in the flooded organic sediment. Our results stress the ecological importance of eulittoral zone in reservoirs with fluctuating water levels where macrophyte growth can be supported by targeted management of water level, thus helping reservoir managers in improving the ecological potential of this type of water bodies.

Krolová M.

2013-05-01

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A hydro-economic model for water level fluctuations: combining limnology with economics for sustainable development of hydropower.  

Science.gov (United States)

Water level fluctuations in lakes lead to shoreline displacement. The seasonality of flooding or beaching of the littoral area affects nutrient cycling, redox gradients in sediments, and life cycles of aquatic organisms. Despite the ecological importance of water level fluctuations, we still lack a method that assesses water levels in the context of hydropower operations. Water levels in reservoirs are influenced by the operator of a hydropower plant, who discharges water through the turbines or stores water in the reservoir, in a fashion that maximizes profit. This rationale governs the seasonal operation scheme and hence determines the water levels within the boundaries of the reservoir's water balance. For progress towards a sustainable development of hydropower, the benefits of this form of electricity generation have to be weighed against the possible detrimental effects of the anthropogenic water level fluctuations. We developed a hydro-economic model that combines an economic optimization function with hydrological estimators of the water balance of a reservoir. Applying this model allowed us to accurately predict water level fluctuations in a reservoir. The hydro-economic model also allowed for scenario calculation of how water levels change with climate change scenarios and with a change in operating scheme of the reservoir (increase in turbine capacity). Further model development will enable the consideration of a variety of additional parameters, such as water withdrawal for irrigation, drinking water supply, or altered energy policies. This advances our ability to sustainably manage water resources that must meet both economic and environmental demands. PMID:25526619

Hirsch, Philipp Emanuel; Schillinger, Sebastian; Weigt, Hannes; Burkhardt-Holm, Patricia

2014-01-01

14

Sensitivity of tributaries to water-level fluctuations along the St-Lawrence corridor, Québec, Canada  

Science.gov (United States)

During the course of the last century, variations in the St-Lawrence water levels, caused by different uses of the river and the Great Lakes, have already had major impacts on riparian habitats and on a number of tributaries. Anticipated changes caused by climate change will only accentuate these impacts. At present, climate change scenarios forecast a decrease of the St-Lawrence water discharge by 20% over the next fifty years, which would correspond to a drop in water level between 0.5 and 1 metre at Montréal. Because the St- Lawrence corridor is in a region of lowlands, such fluctuations in water levels are expected to cause major adjustments in the morphology and longitudinal profiles of the tributaries through the erosion and incision of the river bed. These changes are important because ultimately, the sediment loads delivered to the St-Lawrence river are linked to the erosion processes occurring along its tributaries. However, given the important physical diversity of the tributaries, their sensitivity will differ, making it difficult to predict their individual response to environmental changes, especially given the paucity of data on the present state of the tributaries. Thus, our goal was to obtain data on the variability in morphosedimentology and dynamics of the tributaries in order to infer their sensitivity to fluctuations in baselevels. Bathymetric, hydraulic, and sedimentological surveys were conducted in 2004 and 2005 on five tributaries of the St-Lawrence: the Yamachiche, the St-Maurice, and the Batiscan rivers on the north shore, and the Richelieu and St-François rivers on the south shore. These tributaries cover a wide range of sizes and sedimentological characteristics, from cohesive clays to silts and gravel. Their hydrological regimes are also varied and are in some cases regulated, limiting the sediment capacity of certain tributaries. For example, the Yamachiche and St-François rivers have been under intense agricultural pressure, have fine sediments and have migrated significantly over the last fifty years, highlighting their instability and suggesting that changes in water levels may accentuate these erosion processes. On the other hand, the St-Maurice is highly regulated, has greater bank stability, due to its coarser sediment and intact riparian vegetation, and has remained fairly unmoved. This suggests that this river will respond more slowly to fluctuations in water levels. Investigating the current physical conditions of the tributaries will allow a better understanding of the long-term impacts of sustained periods of low water levels due to environmental change, and will help us develop a sensitivity index of the response of these rivers.

Charron, I.; Roy, A.; Boyer, C.; Verhaar, P.; Biron, P.; Morin, J.

2006-05-01

15

Growth of companies and water level fluctuations of the river Danube  

Science.gov (United States)

Recent studies on growth rate of publicly traded companies revealed interesting scaling properties and universality. Based on the statistical analysis, different models have been proposed to cast light into the inner workings of companies responsible for the phenomena observed. The purpose of this paper is to point out that the properties of the analysed economic data might be present in a wider class of complex systems producing strongly correlated noisy time series. As an illustration, we report an investigation of the daily water-level fluctuations of the river Danube over a period of 87 years, as measured in Nagymaros, Hungary. The Danube data shows similar characteristics to those seen in the company growth. This suggests that a universal description of the statistics should exist for both systems.

Jánosi, Imre M.; Gallas, Jason A. C.

1999-09-01

16

Recent movement on the Garlock Fault as suggested by water level fluctuations in a well in Fremont Valley, California  

Science.gov (United States)

Water levels have been continuously recorded since March 1978 in a well in Fremont Valley, where several strands of the adjacent Garlock fault zone have exhibited both left-lateral displacement and components of normal displacement. Differences in water levels indicate that a fault segment lies between the observation well and a nearby irrigation well. During the 4-year recording period, six sharp fluctuations, or "spikes," were noted. These fluctuations, occurring over 2- to 4-day periods, have amplitudes of 15-30 cm. They appear to be the result of creep events on a nearby fault. Two types of creep events are plausible: (1) normal slip on an en echelon trace of the Garlock fault less than 300 m south of the well, with the north side up relative to Fremont Valley or (2) left-lateral slip on the same fault. Because of the nature of the fluctuations we favor the latter interpretation. Dislocation models utilizing exponential, arc tangent, and skewed cosine functions were used to analyze the water level fluctuations, associated pressure distribution, and fault displacements. The results suggest that creep on the fault ranges from several millimeters to a centimeter for individual events. Estimates of cumulative creep for the period 1978-1982 range from 20 to 50 mm, depending on the particular model employed.

Lippincott, Diane K.; Bredehoeft, John D.; Moyle, W. R., Jr.

1985-02-01

17

Can mercury in fish be reduced by water level management? Evaluating the effects of water level fluctuation on mercury accumulation in yellow perch (Perca flavescens).  

Science.gov (United States)

Mercury (Hg) contamination of fisheries is a major concern for resource managers of many temperate lakes. Anthropogenic Hg contamination is largely derived from atmospheric deposition within a lake's watershed, but its incorporation into the food web is facilitated by bacterial activity in sediments. Temporal variation in Hg content of fish (young-of-year yellow perch) in the regulated lakes of the Rainy-Namakan complex (on the border of the United States and Canada) has been linked to water level (WL) fluctuations, presumably through variation in sediment inundation. As a result, Hg contamination of fish has been linked to international regulations of WL fluctuation. Here we assess the relationship between WL fluctuations and fish Hg content using a 10-year dataset covering six lakes. Within-year WL rise did not appear in strongly supported models of fish Hg, but year-to-year variation in maximum water levels (?maxWL) was positively associated with fish Hg content. This WL effect varied in magnitude among lakes: In Crane Lake, a 1 m increase in ?maxWL from the previous year was associated with a 108 ng increase in fish Hg content (per gram wet weight), while the same WL change in Kabetogama was associated with only a 5 ng increase in fish Hg content. In half the lakes sampled here, effect sizes could not be distinguished from zero. Given the persistent and wide-ranging extent of Hg contamination and the large number of regulated waterways, future research is needed to identify the conditions in which WL fluctuations influence fish Hg content. PMID:25134675

Larson, James H; Maki, Ryan P; Knights, Brent C; Gray, Brian R

2014-10-01

18

Deep bore well water level fluctuations in the Koyna region, India: the presence of a low order dynamical system in a seismically active environment  

Directory of Open Access Journals (Sweden)

Full Text Available Water level fluctuations in deep bore wells in the vicinity of seismically active Koyna region in western India provides an opportunity to understand the causative mechanism underlying reservoir-triggered earthquakes. As the crustal porous rocks behave nonlinearly, their characteristics can be obtained by analysing water level fluctuations, which reflect an integrated response of the medium. A Fractal dimension is one such measure of nonlinear characteristics of porous rock as observed in water level data from the Koyna region. It is inferred in our study that a low nonlinear dynamical system with three variables can predict the water level fluctuations in bore wells.

D. V. Ramana

2009-05-01

19

Vegetational and landscape level responses to water level fluctuations in Finnish, mid-boreal aapa mire – aro wetland environments  

OpenAIRE

Abstract Gradient, which is largely considered to be related to water level in mires, is referred to as a microtopographic mud bottom to carpet to lawn to hummock level gradient or the hummock level to intermediate level (lawn) to flark level gradient. The relationship of this vegetation gradient to various physical water level characteristics was studied. The general classification used in the present summary paper divides the aro vegetation of the inland of Northern Ostrobothnia int...

Laitinen, Jarmo

2008-01-01

20

Late Holocene water level fluctuations of Lake Afourgagh (Middle-Atlas Mountains, Morocco) inferred from charophyte remains  

OpenAIRE

Water level fluctuations of Lake Afourgagh (Middle-Atlas Mountains, Morocco) over the last 2500 years (Late Holocene) have been reconstructed using charophyte remains in the lake sediment archives. The study involved 22 pits (1-3 m deep) dug along a transect across the lake shore terrace. Biogenic activity appears to be a dominant contributor to the accumulation of the lake sediments, as the thickest deposits are tufas composed of charophyte-encrusted stems with numerous gyrogonites (termed "...

De?triche?, Se?bastien; Bre?heret, Jean-gabriel; Soulie?-ma?rsche, I.; Karrat, L.; Macaire, Jean-jacques

2009-01-01

21

The Evaluation of Spatial Fluctuations and Temporal Variability in Estimated Levels of THMs in Drinking Water  

Science.gov (United States)

Chlorine, used by municipal water treatment facilities to disinfect water, reacts with naturally occurring organic matter to produce a host of compounds known as disinfection by-products. In addition to chloroform, brominated species such as bromodichloromethane, dibromochloromethane, and bromoform may also be formed if bromide is present in the source water. Together, these volatile compounds comprise the trihalomethanes (THMs). The results presented in this paper shown that the THM levels were higher in the summer relative to other seasons.

Ristoiu, D.; Haiduc, I.; Culea, M.; Mocan, A.; Chira, R.; Vancea, S.

2007-04-01

22

Water Level Fluctuations in the Congo Basin Derived from ENVISAT Satellite Altimetry  

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Full Text Available In the Congo Basin, the elevated vulnerability of food security and the water supply implies that sustainable development strategies must incorporate the effects of climate change on hydrological regimes. However, the lack of observational hydro-climatic data over the past decades strongly limits the number of studies investigating the effects of climate change in the Congo Basin. We present the largest altimetry-based dataset of water levels ever constituted over the entire Congo Basin. This dataset of water levels illuminates the hydrological regimes of various tributaries of the Congo River. A total of 140 water level time series are extracted using ENVISAT altimetry over the period of 2003 to 2009. To improve the understanding of the physical phenomena dominating the region, we perform a K-means cluster analysis of the altimeter-derived river level height variations to identify groups of hydrologically similar catchments. This analysis reveals nine distinct hydrological regions. The proposed regionalization scheme is validated and therefore considered reliable for estimating monthly water level variations in the Congo Basin. This result confirms the potential of satellite altimetry in monitoring spatio-temporal water level variations as a promising and unprecedented means for improved representation of the hydrologic characteristics in large ungauged river basins.

Mélanie Becker

2014-09-01

23

Seepage Analysis of Rock-Fill Dam Subjected to Water Level Fluctuation: A case study on Gotvand-Olya Dam  

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Full Text Available The Gotvand-Olya Dam is a rock-fill dam, located at Khuzestan province in southwest of Iran. Since the dam is subjected to the daily water level fluctuation, such as rapid drawdown and refill, thus induce a structural impact on the behavior of dam body, it draws many soil engineering concerns. In this paper, seepage analysis of the rock-fill dam was primarily conducted to evaluate the dam safety against the leakage through the dam body. Traditionally, steady-state analysis was employed to investigate the seepage in the dam body, summing that water level is fixed at two cases: high and low water levels. Consequently, it was not able to properly reflect the time-dependent characteristics of seepage phenomena. In this study, seepage analysis was numerically performed using 2-D FEM transient analysis. As a particular boundary condition for an analysis, the water level fluctuation was incorporated to simulate the daily changes. As a result, various seepage phenomena were quantified such as hydraulic gradient, seepage vector and pore water pressure distribution at the corresponding time of interest as the water level rises and recedes. At steady state analysis, the seepage flux at high water level in downstream area was predicted to be 78 l/s. In additions, the seepage flux measured and estimated were both acceptable considering design criteria. The result of this study proves that there is no sign of hazardous sources contributing to the possibility of piping, internal erosion and excess leakage through the dam body.

Ali Beheshti

2013-01-01

24

Properties of Adsorption-Desorption of Pb in Soil of the Water-Level-Fluctuating in Three Gorges Reservoir Region  

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Full Text Available The soil of water-level-fluctuating adsorption and desorption characterisitics of Pb2+ ion in the Three Gorges Reservoir region are studied on pH, organic matter, ionic strength and effect of Pb2+ ion concentration. It is revealed in the law of soil adsorption and desorption of Pb2+ ion in water-level-fluctuationg of the Three Gorges reservoir region, for providing the basis on lead contamination risk assessment and forecasting, pollution control and the use of land resources. Electing purple soil of the main soil type is also studied by using simulation experiments and constant temperature oscillation balance method. With atomic absorption spectrophotometer determination of Pb2+ ion adsorption and desorption volume. The results show that:1pH value very significantyly affects the soil adsorption capacity of Pb2+ ion (ppH>organic matter > Pb2+ ion concentration, affect the Pb2+ soil desorption amount in the order of :pHwater in the Three Gorges Reservoir region, the soil of water-level-fluctuating is affected by various factors, leading to change the soil properties and affect the environmental behavior of heavy metals and way cause enviromental pollution and ecological hazards.

FANG Lu-qiu

2010-05-01

25

Quantifying the rainfall-water level fluctuation process in a geologically complex lake catchment.  

Science.gov (United States)

Simulating hydrologic processes in geologically complex environments is a difficult scientific task since it incorporates high level of uncertainty. Many studies have attempted to accurately quantify the rainfall-water level elevation relationship in freshwater bodies so as to predict flooding and drought events. For this purpose several types of models have been implemented including distributed, black box and conceptual models that often provide efficient results, depending on the availability of reliable data as well as on the level of understanding of the system. Nevertheless, in the particular effort, three different models have been used to describe the relationship between rainfall and water level elevation in Trichonis Lake during the period 1951-1997. A Transfer Function model, a Dynamic Linear Regression and a physically based model, consisting of the lake's water budget equation, its Digital Bathymetric Model and GIS algorithms. These models have been tested to assess their efficiency and applicability in a karstic environment and the aim of the study was to find the best modeling option for developing sustainable water management plans and establishing a flooding/drought warning system in the particular lake catchment. The results indicated that in areas with geologically complex conditions, simple, physically-based models operate better than mechanistic models which usually cannot describe adequately the complexity of the system. PMID:16741814

Elias, Dimitriou; Ierotheos, Zacharias

2006-08-01

26

Dramatic water-level fluctuations in lakes under intense human impact: modelling the effect of vegetation, climate and hydrogeology  

Science.gov (United States)

Lakes form a highly important ecosystem in the glacial terrain of northern Europe and America, but their hydrology remains understudied. When the water-level of a lake drops significantly and rises again in a time span of half a century and the widespread explanation of the fluctuations seems insufficient, then it raises a question: how do different anthropogenic and natural processes actually affect the formation of a lakes' water body. The abovementioned scenario applies to three small closed-basin Estonian lakes (L. Ahnejärv, L. Kuradijärv and L. Martiska) analysed in the current study. These lakes suffered a major water-level drop (up to 3.8 m) between 1946 and 1987 and a major rise between 1987 and 2010, from 1 m (L. Ahnejärv) to 2.5 m (L. Kuradijärv). Decreasing and increasing groundwater abstraction near the lakes has been widely considered to be the only reason for the fluctuations. It is true that the most severe drop in the lake levels did occur after 1972 when groundwater abstraction for drinking water started in the vicinity of the lakes. However, the lake levels started to fall before the groundwater abstraction began and for the time being the lake levels have risen to a higher level than in the 1970s when the quantity of annually abstracted groundwater was similar to nowadays. Therefore the processes affecting the formation of the lakes' water body prove to be more complex than purely the hydrogeological change caused by groundwater abstraction. A new deterministic water balance model (where the evaporation from the lake surface was calculated by Penman equation and the catchment runoff by Thornthwaite-Mather soil-moisture model), compiled for the study, coupled with LiDAR-based GIS-modelling of the catchments was used to identify the different factors influencing the lakes' water level. The modelling results reveal that the moderate drop in lake water levels before the beginning of groundwater abstraction was probably caused by the growth of a coniferous forest on the lake catchments, due to which evapotranspiration and subsequently runoff from the catchment decreased. The forest had been destroyed by wildfires during World War II. The water-level rise that the lakes have gone through in the last 20 years has in the case of L. Ahnejärv been caused by changing meteorological conditions (precipitation, air temperature and wind speed). In the case of Lakes Kuradijärv and Martiska the change has been caused by both the raise of groundwater level (caused by the decreasing groundwater abstraction) and the change of meteorological conditions. Therefore the vegetation change on the catchment and changes in meteorological conditions have played as important or, at times, even more important role in the water-level fluctuations than changes in the hydrogeological conditions. Although concentrating on three specific lakes in a specific region, the result of the study indicate the complexity of factors influencing the amount of water stored in a lake at a certain moment. Therefore it manifests a need for improved models in order to improve lake management around the world.

Vainu, M.

2012-04-01

27

Water level fluctuations in a coastal lagoon: El Yali Ramsar wetland, Chile  

OpenAIRE

El Yali coastal reserve is the most important wetland complex in Mediterranean climate central Chile, especially due to the native and foreign bird fauna which arrives here periodically. The coastal lagoon, part of a microtidal estuary (1.2m tidal range), is a shallow (< 1m depth) dynamic system and unique site of coexistence of northern halophyte and southern palustrian riparian vegetation. This study identifies and quantifies the effect of forcing variables in the lagoon water level over 1 ...

Dussaillant, Alejandro; Galdames, Pablo; Sun, Chi-le

2009-01-01

28

Evaluation of Radionuclides, Toxic Metals and Fluctuation ofRadioactivity Level in Muria Water  

International Nuclear Information System (INIS)

Study on Radionuclides, toxic metals and radioactivity level fluctuationin Water samples of Muria area have been carried out. The sampling locationwere Sepalung Tubanan, Hulu Putih, Balong, Geulis and Banjaran river, LemahAbang, Krakal and Baron coasts. Alpha, betha, and gamma radioactivity levelswere gross counted. Radionuclides identification were done by using gammaspectrometer. Pu-239/240 were analyzed by dilution and solvent extractionstep before counted by alpha spectrometer. Toxic metals were analyzed byInstrumental Neutron Activation Method, with the neutron flux of5.1010.n.cm-2.s-1. Data collection of toxic elements was carried outduring 4 years since 1996 to 1999, and 2 years for radioactivity level studysince 1998 and 1999. High concentration of Zn in Balong and Hulu Putih riverwater samples in 1999 higher than the governmental quality standard value foragriculture. The radionuclides contaminant as Pu-239/240 and Cs-137 were notdetected, and the radioactivity level and identified radionuclides were allnaturally. (author)

29

Community metabolism in a deep (stratified) tropical reservoir during a period of high water-level fluctuations.  

Science.gov (United States)

As long as lakes and reservoirs are an important component of the global carbon cycle, monitoring of their metabolism is required, especially in the tropics. In particular, the response of deep reservoirs to water-level fluctuations (WLF) is an understudied field. Here, we study community metabolism through oxygen dynamics in a deep monomictic reservoir where high WLF (~10 m) have recently occurred. Simultaneous monitoring of environmental variables and zooplankton dynamics was used to assess the effects of WLF on the metabolism of the eutrophic Valle de Bravo (VB) reservoir, where cyanobacteria blooms are frequent. Mean gross primary production (P g) was high (2.2 g C m(-2) day(-1)), but temporal variation of P g was low except for a drastic reduction during circulation attributed to zooplankton grazing. The trophogenic layer showed net autotrophy on an annual basis, but turned to net heterotrophy during mixing, and furthermore when the whole water-column oxygen balance was calculated, considering the aphotic respiration (Raphotic). The high total respiration resulting (3.1 g C m(-2) day(-1)) is considered to be partly due to mixing enhanced by WLF. Net ecosystem production was equivalent to a net export of 3.4 mg CO??m(-2) day(-1) to the atmosphere. Low water levels are posed to intensify boundary-mixing events driven by the wind during the stratification in VB. Long-term monitoring showed changes in the planktonic community and a strong silicon decrease that matched with low water-level periods. The effects of low water-level on metabolism and planktonic community in VB suggest that water-level manipulation could be a useful management tool to promote phytoplankton groups other than cyanobacteria. PMID:24994617

Valdespino-Castillo, Patricia M; Merino-Ibarra, Martín; Jiménez-Contreras, Jorge; Castillo-Sandoval, Fermín S; Ramírez-Zierold, Jorge A

2014-10-01

30

Simulation of ground-water level fluctuations using recharge estimated by field infiltrometer measurements  

Science.gov (United States)

An infiltrometer was used at multiple locations at a site in Lee County, Fl. to define the spatial variability in infiltration parameters. Water-level data from a well at this site were collected hourly and used to determine the temporal variability in recharge. These results were used to define recharge in a representative stochastic numerical model of the aquifer. Model results without recharge compare well with existing analytical solutions for spatial head variability. Simulations with representative recharge events indicate that recharge produces a significant to dominant effect on head variability, which creates dispersion of contaminants, and that small-scale spatial and temporal recharge variations are the predominant mechanism causing the head variations.

Swain, E.D.

1997-01-01

31

Separated by sand, fused by dropping water: habitat barriers and fluctuating water levels steer the evolution of rock-dwelling cichlid populations in Lake Tanganyika.  

Science.gov (United States)

The conditions of phenotypic and genetic population differentiation allow inferences about the evolution, preservation and loss of biological diversity. In Lake Tanganyika, water level fluctuations are assumed to have had a major impact on the evolution of stenotopic littoral species, though this hypothesis has not been specifically examined so far. The present study investigates whether subtly differentiated colour patterns of adjacent Tropheus moorii populations are maintained in isolation or in the face of continuous gene flow, and whether the presumed influence of water level fluctuations on lacustrine cichlids can be demonstrated in the small-scale population structure of the strictly stenotopic, littoral Tropheus. Distinct population differentiation was found even across short geographic distances and minor habitat barriers. Population splitting chronology and demographic histories comply with our expectation of old and rather stable populations on steeper sloping shore, and more recently established populations in a shallower region. Moreover, population expansions seem to coincide with lake level rises in the wake of Late Pleistocene megadroughts ~100 KYA. The imprint of hydrologic events on current population structure in the absence of ongoing gene flow suggests that phenotypic differentiation among proximate Tropheus populations evolves and persists in genetic isolation. Sporadic gene flow is effected by lake level fluctuations following climate changes and controlled by the persistence of habitat barriers during lake level changes. Since similar demographic patterns were previously reported for Lake Malawi cichlids, our data furthermore strengthen the hypothesis that major climatic events synchronized facets of cichlid evolution across the East African Great Lakes. PMID:21518059

Koblmüller, Stephan; Salzburger, Walter; Obermüller, Beate; Eigner, Eva; Sturmbauer, Christian; Sefc, Kristina M

2011-06-01

32

Update on the bathymetry of Lake Mweru (Zambia), with notes on water level fluctuations  

OpenAIRE

A new bathymetric map of Lake Mweru was developed, displaying previously unknown morphological features and correcting the shape of the shoreline as presented in older maps. Water depth was measured during 11 transect cruises in early 1994. Two depressions were found in the north-eastern section of the lake, with maximum depths of 20m and 27m, respectively. The average depth of the lake was calculated to be 7.5m. The surface area (5 120km2) and volume (38.2 × 109m3) were found to be much gre...

Bos, A. R.; Kapasa, C. K.; Zwieten, P. A. M.

2006-01-01

33

Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake, 1984 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

This study was initiated in the fall of 1981 to delineate the extent of successful shoreline spawning of kokanee salmon in Flathead Lake and determine the impacts of the historic and present operations of Kerr and Hungry Horse dams. An investigation of the quantity and quality of groundwater and other factors affecting kokanee reproductive success in Flathead Lake began in the spring of 1982. A total of 719 redds were counted in 17 shoreline areas of Flathead Lake in1983 compared to 592 in 1981 and 1,029 in 1982. Shoreline spawning contributed three percent to the total kokanee spawning in the Flathead drainage in 1983. Fifty-nine percent of the redds were located above 2883 ft, the operational minimum pool. The majority of those redds were constructed between 2885 and 2889 ft. In areas above minimum pool, intergravel dissolved oxygen concentrations were adequate for embryo survival and exhibited a decrease with depth. Limited data indicated apparent velocity may be the key in determining redd distribution. Seventy-five percent of the redds located below minimum pool were constructed in a zone between 2869 and 2883 ft. In individual areas, apparent velocity measurements and intergravel dissolved oxygen concentrations were related to redd density. The variation in intergravel dissolved oxygen concentrations in the Yellow Bay spawning area was partially explained by lake stage fluctuation. As lake stage declined, groundwater apparent velocity increased which increased intergravel dissolved oxygen concentrations. Mean survival to the eyed stage in the three areas below minimum pool was 43 percent. Prior to exposure by lake drawdown, mean survival to the eyed stage in spawning areas above minimum pool was 87 percent. This indicated habitat most conducive to successful embryo survival was in gravels above 2883 ft. prior to significant exposure. Survival in redds exposed to either extended periods of drawdown or to temperatures less than -10% was significantly reduced to a mean of 20-30 percent. Survival in individual spawning areas exposed by lake drawdown varied from 0 to 65 percent. Groundwater reaction to lake stage explained some of the variation in individual spawning area survival. Three types of groundwater reaction to lake stage were identified. Increased survival in exposed redds resulted from two of the three types. A significant statistical relationship was determined between embryo survival and the number of days exposed by lake drawdown. The operation of Kerr Dam in 1983-84 was characterized by an early decline in lake stage, a longer period near minimum pool and a later and more rapid filling compared to the operation seen in 1981-82 and 1982-83. Based on the survival relationship observed in natural redds exposed by drawdown in 1983-84, complete mortality from exposure would have occurred to all redds constructed above 2884.7 ftor 90 percent of all redds constructed above minimum pool. Emergence traps placed over redds below minimum pool in Gravel, Blue, and Yellow bays captured fry in Gravel and Blue bays only. Duration of fry emergence in1984 was three weeks longer than in 1982 or 1983, but was not related to the date of initial redd construction. Survival to fry emergence in Gravel Bay was calculated to be 28.9 percent of egg deposition or 57,484 fry. Survival to fry emergence above and below the zone of greatest redd density was 33.6 and 245 percent, respectively, indicating a relationship between survival and spawner site selection. After analysis of the historic operation of Kerr Dam, it is believed that the dam has, and is continuing to have, a significant impact on successful shoreline spawning of kokanee salmon in Flathead Lake. Based on the evidence that prolonged exposure of salmonid embryo by dewatering causes significant mortality, the number of days the lake was held below various foot increments (2884 ft to 2888 ft) during the incubation period was investigated. The annual change in the number of days the lake was held below 2885 ft was further investigated because 80-90 percent of the redds cons

Decker-Hess, Janet; Clancey, Patrick (Montana Department of Fish, Wildlife and Parks, Kalispell, MT)

1984-03-01

34

Environmental assessment for the natural fluctuation of water level in Par Pond and reduced water flow in Steel Creek below L-Lake at the Savannah River Site  

International Nuclear Information System (INIS)

The Savannah River Operations Office Strategic Plan directs Savannah River Site (SRS) to find ways to reduce operating costs, and to determine what site infrastructure must be maintained and what infrastructure is surplus. Because of the mission change, L-Lake, Par Pond, and the river water system are no longer needed to support current missions and therefore provide an opportunity for operating cost reduction. If SRS determines that L-Lake, Par Pond, and the river water system are no longer needed to support future missions and are considered surplus, appropriate NEPA documentation will be prepared. The purpose of the proposed action in this Environmental Assessment is to begin an examination of the need for the Site's river water system by (1) developing data needed to evaluate the potential environmental impacts of further reducing or eliminating the flow demands from the Site's river water system and; (2) evaluating the potential of reducing operating costs by allowing the water level in Par Pond to fluctuate naturally through reduced pumping. This action also includes reducing the current flow rates from L-Lake to Steel Creek to natural stream flows while maintaining full pool. The recently approved Par Pond CERCLA Interim Action Proposed Plan (IAPP) committed to evaluate in a NEPA document the environmental consequences of this proposed action. This document evaluated the remediation of human health and ecological risks associated with the three year drawdown of Par Pond. Should any of the parameters sampled in the reservoir and streams (e.g., water quality, biota, etc.) exceed established threshold levels during the implementation of the proposed action, water would again be pumped into the reservoir to minimize any impacts by bringing the water level back to an appropriate level about 58.2 m (195 ft)

35

Environmental assessment for the natural fluctuation of water level in Par Pond and reduced water flow in Steel Creek below L-Lake at the Savannah River Site  

Energy Technology Data Exchange (ETDEWEB)

The Savannah River Operations Office Strategic Plan directs Savannah River Site (SRS) to find ways to reduce operating costs, and to determine what site infrastructure must be maintained and what infrastructure is surplus. Because of the mission change, L-Lake, Par Pond, and the river water system are no longer needed to support current missions and therefore provide an opportunity for operating cost reduction. If SRS determines that L-Lake, Par Pond, and the river water system are no longer needed to support future missions and are considered surplus, appropriate NEPA documentation will be prepared. The purpose of the proposed action in this Environmental Assessment is to begin an examination of the need for the Site`s river water system by (1) developing data needed to evaluate the potential environmental impacts of further reducing or eliminating the flow demands from the Site`s river water system and; (2) evaluating the potential of reducing operating costs by allowing the water level in Par Pond to fluctuate naturally through reduced pumping. This action also includes reducing the current flow rates from L-Lake to Steel Creek to natural stream flows while maintaining full pool. The recently approved Par Pond CERCLA Interim Action Proposed Plan (IAPP) committed to evaluate in a NEPA document the environmental consequences of this proposed action. This document evaluated the remediation of human health and ecological risks associated with the three year drawdown of Par Pond. Should any of the parameters sampled in the reservoir and streams (e.g., water quality, biota, etc.) exceed established threshold levels during the implementation of the proposed action, water would again be pumped into the reservoir to minimize any impacts by bringing the water level back to an appropriate level about 58.2 m (195 ft).

NONE

1995-08-01

36

Comparison between Neural Networks and Adaptive Neuro-fuzzy Inference System in Modeling Lake Kerkini Water Level Fluctuation Lake Management using Artificial Intelligence  

Directory of Open Access Journals (Sweden)

Full Text Available This study presents lake Kerkini water level simulation. Water level depends on a large number of parameters and procedures which are usually complex or non-linear. Water level was calculated, by using a model based on visual basic language. The model took account of all parameters that contribute to water level. Simulation was achieved when the model output approximated the available measured values. Afterwards, the same project was implemented by using artificial intelligence methods. These are, artificial neural networks and adaptive neuro fuzzy inference system. The basic advantage of this implementation is the fact that the output is obtained without having to use all the parameters that contribute to the final result. This means that they can be implemented for modeling systems where the procedures are not fully known or when there is a large parameter number affecting the result. Both models showed a great performance in simulating water level fluctuation and they are also suggested for prediction.

Christos Evangelides

2011-01-01

37

Pattern and Biodiversity of Plant Community in Water-Level-Fluctuation Zone of Pengxi River After 156 m Impoundment of Three Gorges Reservoir  

OpenAIRE

After impounding to altitude of 156 m, species, spatial pattern and biodiversity of plant community in water-level-fluctuation zone of Three Gorges Reservoir had significant changes. The plant community under altitude of 175 m beside Pengxi River and its tributary Baijia Stream in Kaixian County was studied from July to September, 2008. 108 herb sampling quadrates along five sampling transects, three beside Pengxi River and two beside Baijia Stream, were conducted. The results showed that the...

Wang, Jian-xiu; Sun, Rong; Yuan, Xing-zhong; Liu Hong; Wang Qiang

2009-01-01

38

The effect of water-level fluctuations on swamp forest colonization by seedlings of <i>Tabebuia cassinoides</i> DC. (Bignoniaceae)  

OpenAIRE

Establishment of Tabebuia cassinoides seedlings is related to water-level fluctuations in southeastern Brazil swamp forests. Nine years of annual monitoring of 48 individuals established during a drought in November 1997, when the swamp was unflooded, suggested that their establishment depends on this unpredictable event. This conclusion is further sustained by the wide variability of the seedling cohort size structure, and the fascicular root conformation that holds the shoots erect.

Mariana de Andrade Iguatemy; Pablo José Francisco Pena Rodrigues

2011-01-01

39

Pattern and Biodiversity of Plant Community in Water-Level-Fluctuation Zone of Pengxi River After 156 m Impoundment of Three Gorges Reservoir  

Directory of Open Access Journals (Sweden)

Full Text Available After impounding to altitude of 156 m, species, spatial pattern and biodiversity of plant community in water-level-fluctuation zone of Three Gorges Reservoir had significant changes. The plant community under altitude of 175 m beside Pengxi River and its tributary Baijia Stream in Kaixian County was studied from July to September, 2008. 108 herb sampling quadrates along five sampling transects, three beside Pengxi River and two beside Baijia Stream, were conducted. The results showed that there are 98 species of vascular plant belong to 38 families, 29 generas. 52 species of wetland plant were investigated. Therophytes(52.0% and cryptophyte (31.6% were the dominant compositions of Raunkiaer’s life. The plant community of study area belonged to 11 associations. Floodplain annual herb zone, Xanthium sibiricum zone, Paspalum paspaloides zone and Imperata cylindrica zone dispersed at the lateral side of Pengxi River and Baijia stream from riparian to altitude of 175 m. The variation and pattern of soil water content significantly influenced the distribution of plant community in water-level-fluctuation zone. There were a low herb biodiversity in water-lever fluctuation zone.

WANG Jian-xiu

2009-10-01

40

Changes in rotifer communities regarding to the water-level fluctuations in the floodplain Gemenc, Danube (Hungary  

Directory of Open Access Journals (Sweden)

Full Text Available The planktonic rotifer communities in three hydrodynamicaly different river-arms at the floodplain of the Danube River at Gemenc have been studied. In the numerous arms the current has different speeds depending on the water level, therefore the physical and chemical parameters (temperature, conductivity, transparency, dissolved oxygen content are different. We have found forty-six rotifer taxa in the area, but the species-composition changes seasonally. There are therefore big differences in the qualitative and quantitative data between the main arm and the other branches. At high water levels (flood, the rotifer communities of the area are uniformized but, at low water levels the area becomes divided into a series of different water bodies, some near to the lake-state. This phenomenon develops a few days after the flood. The species composition and the abundance relations of the planktonic rotifer communities reflect this effect.

Schöll, K.

2006-12-01

41

Influence of water level fluctuation on the mortality and aboveground biomass of the aquatic macrophyte Eleocharis interstincta (VAHL roemer et schults  

Directory of Open Access Journals (Sweden)

Full Text Available The goal of this study was to study the biometric alterations of Eleocharis interstincta in response to water level fluctuations in Cabiúnas Lagoon, located on the northern coast of the state of Rio de Janeiro, in the municipality of Macaé. Three quadrats of 0.0625 m² were harvested every two weeks from June/1997 to June/1998; samples were separated into stems, dead stems (detritus and rhizome; lenghted, dried and weighted. The water level fluctuated seasonally in the macrophyte stand with two periods of drawdown. The first period occurred naturally at the end of winter and beginning of spring, when rainfall in the area was normally lowest. The second period of drawdown was the result of an artificial breaching of the sandbar that isolate the lagoon from the sea. The breach was made in the summer, at the time of highest rainfall, when the water level in the lagoon reached the maximum value recorded during the study (1.35 m. There was a strongly positive correlation of the water level with stems mean height and aboveground biomass, indicating that water level played an important role in the determination of these parameters. There was a significant difference between stem height (ANOVA; p < 0.001 and biomass (ANOVA; p < 0.001 in each sampling period, ranging from 143.9 cm and 338.8 g dry wt.m-2, before the sandbar opening, to 16.3 cm and 20.2 g dry wt.m-2 respectively after the sandbar breaching. The drastic variation of the water level, leading mass mortality of the stems, together with the lowest mean biomass/stem (0.057 g dry wt.individual-1, recorded after the sandbar breaching, did not represent a strong disturbance for E. interstincta, since the resilience time estimated for this population was about 30 days.

Santos Anderson Medeiros dos

2004-01-01

42

Infiltration properties of covering soil into the void of buried concrete waste due to fluctuation of ground water level and its prevention  

International Nuclear Information System (INIS)

Low level radioactive concrete waste will be produced in future by breaking up the nuclear facilities, and the waste will be disposed in shallow depth of ground. In order to prepare for those situation, it is needed to clarify the infiltration properties of the covering soil into the void of buried concrete waste due to the fluctuation of ground water level and to develop the prevention methods against the infiltration of the covering soil. In this study, full-scale concrete structure specimens were broken up, and were compacted in large scale testing boxes and a series tests changing water level up and down in the concrete waste and covering soil were performed. From the test results, it was found that the appropriate filter installed between the covering soil and the concrete waste, enable us to prevent the infiltration of covering soil into the void of concrete waste. (author)

43

Analysis of water-level fluctuations of Lakes Winona and Winnemissett-- two landlocked lakes in a karst terrane in Volusia County, Florida  

Science.gov (United States)

The water levels of Lakes Winona and Winnemissett in Volusia County, Fla., correlate reasonably well during dry spells but only poorly during wet spells. Disparities develop mostly at times when the lake levels rise abruptly owing to rainstorms passing over the lake basins. The lack of correlation is attributed to the uneven distribution of the storm rainfall, even though the average annual rainfall at National Weather Service gages in the general area of the lakes is about the same. Analyses of the monthly rainfall data show that the rainfall variability between gages is sufficient to account for most of the disparity between monthly changes in the levels of the two lakes. The total annual rainfall at times may differ between rainfall gages by as much as 15 to 20 inches. Such differences tend to balance over the long term but may persist in the same direction for two or more years, causing apparent anomalies in lake-level fluctuations. (Woodard-USGS)

Hughes, G.H.

1979-01-01

44

Water-Level Fluctuations of Urmia Lake: Relationship with the Long-Term Changes of Meteorological Variables (Solutions for Water-Crisis Management in Urmia Lake Basin)  

OpenAIRE

Urmia Lake in northwest of Iran, through the recent years has been extremely faced with the water crisis. Climate variations and anthropogenic impacts could be two main affiliated factors in this regard. We considered the long term data series of precipitation, temperature and evaporation in monthly and yearly scales in order to compare to water-level values of Urmia Lake. The statistics approaches such ...

Mojtaba Zoljoodi; Ali Didevarasl

2014-01-01

45

Ecological Engineering of Drawdown Wetlands Based on Water-level Fluctuation-Baijia Stream in the Three Gorges Reservoir as a Case Study  

Directory of Open Access Journals (Sweden)

Full Text Available The Three Gorges Reservoir (TGR provides the benefits of flood control, electricity generation and improved transportation along the river corridor. For the purpose of flood control, the reservoir height varies between 145 m and 175 m above sea level, creating a reservoir littoral zone of about 350 km2 in total area distributed along more than 1200 km of shoreline. Most of the littoral zone is flooded during October to May and relatively dry during the remainder of the year. Water level regulation has caused marked ecological changes in the littoral zone of TGR. The littoral zone formed after impounded by TGR not only is the crucible to us, but also the ecological opportunity. The vegetation of large-scale hydro-fluctuation belt is a very valuable resource, if properly used, can turn harm into advantage. In view of the current status and existing problems of the littoral wetland in TGR, we should focus on utilizing resources of the littoral wetland eco-friendly. Based on the needs for the littoral wetland transform into the multifunctional ecological economic benefit such as increasing carbon sources, biological production, and environmental purification, we must develop the ecological engineering model of sustainable utilizing the wetland resources of the littoral zone. In view of the environment problems of TGR and its characteristics of water level fluctuation, the ecological engineering focusing on restoration of littoral wetlands have been carried out since 2008. The eco-logical engineering was mainly conducted at littoral wetlands in Baijia stream of Pengxi River of TGR, including dike-pond system, submergence tolerance wetland-woods and waterfowl habitats recreate projects. The design principle and process for the ecological engineering of littoral wetlands restoration under the condition of the periodic water level change was described in details in this paper. Effects of the ecological engineering and the benefits to the environments were assessed. In the end of the article we proposed that the ecological engineering focus on the restoration of littoral wetlands, also should consider uti.

WANG Qiang

2012-05-01

46

40 CFR 230.24 - Normal water fluctuations.  

Science.gov (United States)

... 2010-07-01 false Normal water fluctuations. 230.24 Section 230.24 Protection...Aquatic Ecosystem § 230.24 Normal water fluctuations. (a) Normal water fluctuations in a natural aquatic system consist...

2010-07-01

47

Global Warming and Caspian Sea Level Fluctuations  

CERN Document Server

Coastal regions have a high social, economical and environmental importance. Due to this importance the sea level fluctuations can have many bad consequences. In this research the correlation between the increasing trend of temperature in coastal stations due to Global Warming and the Caspian Sea level has been established. The Caspian Sea level data has been received from the Jason-1 satellite. It was resulted that the monthly correlation between the temperature and sea level is high and also positive and almost the same for all the stations. But the yearly correlation was negative. It means that the sea level has decreased by the increase in temperature.

Ardakanian, Reza

2013-01-01

48

Comparison between Neural Networks and Adaptive Neuro-fuzzy Inference System in Modeling Lake Kerkini Water Level Fluctuation Lake Management using Artificial Intelligence  

OpenAIRE

This study presents lake Kerkini water level simulation. Water level depends on a large number of parameters and procedures which are usually complex or non-linear. Water level was calculated, by using a model based on visual basic language. The model took account of all parameters that contribute to water level. Simulation was achieved when the model output approximated the available measured values. Afterwards, the same project was implemented by using artificial intelligence methods. These...

Christos Evangelides; Cristos Tzimopoulos; Leonidas Mpallas

2011-01-01

49

Plant community characteristics and their responses to environmental factors in the water level fluctuation zone of the three gorges reservoir in China.  

Science.gov (United States)

The annual water level regulating of the Three Gorges Reservoir prolonged the submerged duration (from 2 to 8 months) and resulted in the reversal of natural flood rhythms (winter submerged). These changes might alter plant community characteristics in the water level fluctuation zone (WLFZ). The aim of this study was to determine the plant community characteristics in the WLFZ and their responses to the environmental factors (i.e., annual hydrological regulation, topographic characteristics, soil physical properties and soil nutrients). The height, coverage, frequency and biomass of each plant species and the soil properties at each elevation zone (150, 155, 160, 165 and 170 m) were measured from March to September in 2010. Univariate two-factor analysis and redundancy analysis (RDA) were used to analyze the spatial and temporal variations of the community characteristics and identify the key environmental factors influencing vegetation. We found that 93.2 % of the species analysed were terrestrial vascular plants. Annual herbs made up the highest percentage of life forms at each altitude. The differences in the species number per square metre, the Shannon-Wiener diversity index and the biomass of vegetation demonstrated statistical significance with respect to sampling time but not elevation. The most dominant species at altitudes of 150, 155, 160, 165 and 170 m were Cynodon dactylon, Cyperus rotundus, Digitaria sanguinalis, Setaria viridis and Daucus carota, respectively. The concentrations of soil nutrients appeared to be the lowest at an altitude of 150 m, although the differences with respect to elevation were not significant. The results of the RDA indicated that the key factors that influenced the species composition of vegetation were elevation, slope, pH and the concentration of soil available phosphorus. PMID:23589274

Zhang, Zhiyong; Wan, Chengyan; Zheng, Zhiwei; Hu, Lian; Feng, Kun; Chang, Jianbo; Xie, Ping

2013-10-01

50

Tidal water table fluctuations in a sandy ocean beach  

Science.gov (United States)

Tidal water table fluctuations observed for 27 days in a gently sloped ocean beach are predicted well by numerical models based on the Boussinesq equation driven with the observed 10 min-averaged shoreline (ocean-beach intersection) motion. Diurnal and semidiurnal water table fluctuations are almost completely damped 100 m landward of the mean shoreline location on this fine-grained sand beach, but fluctuations at spring-neap periods (?14 days) are attenuated less. Comparison of the observations with the predictions suggests that the asymmetries in the water table level time series measured in this study result from nonlinearity owing to the large (relative to the wavelength) horizontal shoreline excursions, rather than from nonlinearity owing to finite-amplitude water table fluctuations. Cross-shore variations of the aquifer depth are predicted to have a small effect on the landward decay rate of the water table fluctuations. The seepage face width is predicted accurately and depends on the nonplanar beach profile. In general, the development of a seepage face is predicted to have little effect on the water table level landward of the intertidal region.

Raubenheimer, B.; Guza, R. T.; Elgar, Steve

1999-08-01

51

Spatial patterns of zooplanktivore Chirostoma species (Atherinopsidae) during water-level fluctuation in the shallow tropical Lake Chapala, Mexico: seasonal and interannual analysis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in spanish El presente estudio describe la influencia que tiene la fluctuación del nivel del agua en la distribución de los peces a dos diferentes escalas: estacional (estiaje y lluvias) e interanual (condiciones de bajo y alto volumen). El análisis de las relaciones de abundancia entre tres especies zooplanct [...] ófagas de Chirostoma en quince sitios del Lago de Chapala, México, reveló una influencia estadísticamente significativa en las condiciones contrastantes (P=0.0002). Estacionalmente, la segregación estuvo más relacionada a la dominancia de las especies en la época de estiaje y exclusivamente relacionada a las características ambientales en la época de lluvias. Interanualmente, la influencia biótica se presenta en los episodios más someros y más profundos del lago. Las características ambientales influenciaron la distribución de las especies cuando el lago alcanzó el 25% de su volumen. El sitio geográfico, profundidad, temperatura y salinidad fueron los principales factores que influenciaron la distribución de los peces. Estos resultados enfatizan la necesidad de implementar diferentes estrategias de manejo de acuerdo al volumen del lago, particularmente cuando se alcanza un umbral crítico. Abstract in english This study addresses the influence of water-level fluctuations on fish distribution at two temporal scales: seasonal (dry and rainy) and interannual (low and high volume conditions). The analysis of abundance relationships among three zooplanktivore Chirostoma species at fifteen sites in Lake Chapal [...] a, Mexico, revealed the significant influence of contrasting conditions (P=0.0002). Seasonally, segregation was more related to species dominance in the dry season and exclusively related to environmental characteristics in the rainy season. Interanually, biotic influence occurred in the shallowest and the deepest episodes of the lake. Environmental characteristics influenced species distribution when the lake reached 25% of its volume. Site, depth, temperature, and salinity were the leading factors influencing fish distribution. These results emphasize the necessity to implement different management strategies according to lake volume, particularly when a critical threshold is reached.

Rodrigo, Moncayo-Estrada; Carlos, Escalera-Gallardo; Owen T., Lind.

52

Spatial patterns of zooplanktivore Chirostoma species (Atherinopsidae during water-level fluctuation in the shallow tropical Lake Chapala, Mexico: seasonal and interannual analysis  

Directory of Open Access Journals (Sweden)

Full Text Available This study addresses the influence of water-level fluctuations on fish distribution at two temporal scales: seasonal (dry and rainy and interannual (low and high volume conditions. The analysis of abundance relationships among three zooplanktivore Chirostoma species at fifteen sites in Lake Chapala, Mexico, revealed the significant influence of contrasting conditions (P=0.0002. Seasonally, segregation was more related to species dominance in the dry season and exclusively related to environmental characteristics in the rainy season. Interanually, biotic influence occurred in the shallowest and the deepest episodes of the lake. Environmental characteristics influenced species distribution when the lake reached 25% of its volume. Site, depth, temperature, and salinity were the leading factors influencing fish distribution. These results emphasize the necessity to implement different management strategies according to lake volume, particularly when a critical threshold is reached.El presente estudio describe la influencia que tiene la fluctuación del nivel del agua en la distribución de los peces a dos diferentes escalas: estacional (estiaje y lluvias e interanual (condiciones de bajo y alto volumen. El análisis de las relaciones de abundancia entre tres especies zooplanctófagas de Chirostoma en quince sitios del Lago de Chapala, México, reveló una influencia estadísticamente significativa en las condiciones contrastantes (P=0.0002. Estacionalmente, la segregación estuvo más relacionada a la dominancia de las especies en la época de estiaje y exclusivamente relacionada a las características ambientales en la época de lluvias. Interanualmente, la influencia biótica se presenta en los episodios más someros y más profundos del lago. Las características ambientales influenciaron la distribución de las especies cuando el lago alcanzó el 25% de su volumen. El sitio geográfico, profundidad, temperatura y salinidad fueron los principales factores que influenciaron la distribución de los peces. Estos resultados enfatizan la necesidad de implementar diferentes estrategias de manejo de acuerdo al volumen del lago, particularmente cuando se alcanza un umbral crítico.

Rodrigo Moncayo-Estrada

2011-01-01

53

Spatial-temporal Dynamics of Vegetation in the Newly Created Water-level-fluctuation Zone of Three Gorges Reservoir:a Case Study in Baijia Stream, Kaixian County, China  

OpenAIRE

"After impoundent of the Three Gorges Reservoir, a large permanent sample plot was placed in its water-level-fluctuation zone beside Baijia Stream, Kaixian County, China. Vegetation in the plot was investigated in the summer of 2008,2009 and 2010. The result indicated that community' s component, biodiversity and aboveground biomass showed obvious spatial-temporal dynamics. Total spiecies number of vascular flora inside decreased yearly, from 52 species in 2008 to 41 species in 2009 and to 35...

Yuan, Xing-zhong; Xiong, Sen; Zhang, Yue-wei; Liu, Hong; Wang, Qiang

2012-01-01

54

Fluctuation of Groundwater Levels and Recharge Patterns in Northern Ghana  

Directory of Open Access Journals (Sweden)

Full Text Available Evaluating groundwater levels and recharge patterns is part of sustainably managing the water supply and predicting the possibility of water shortages, especially in light of climate change, extreme events (floods/droughts, increasing population and development. In the northern region of Ghana, groundwater is increasingly relied upon as a source of potable water for rural populations, but seasonal and inter-annual fluctuations of groundwater levels and recharge patterns are not always known. The fluctuation of groundwater levels on a seasonal basis shows that groundwater levels at all sites increase in response to seasonal precipitation. On an annual basis, all sites show an overall net decline of groundwater levels over the study period, which may be associated with below-average departures of precipitation during five of the seven study years. The variability of recharge patterns among five sites is attributed to the spatio-temporal variability of precipitation and hydrogeologic site uniqueness. The overarching potential benefit of this study is to facilitate closing knowledge gaps and contribute to a foundation for a more robust evaluation of groundwater resources in the area, especially as more data become available.

Alexandra Lutz

2014-12-01

55

Hydrological processes and water resources management in a dryland environment IV: Long-term groundwater level fluctuations due to variation in rainfall  

OpenAIRE

To evaluate the effects of variations in rainfall on groundwater, long-term rainfall records were used to simulate groundwater levels over the period 1953-96 at an experimental catchment in south-east Zimbabwe. Two different modelling methods were adopted. Firstly, a soil water balance model (ACRU) simulated drainage from daily rainfall and evaporative demand; groundwater levels were predicted as a function of drainage, specific yield and water table height. Secondly, the cumulative ra...

Butterworth, J. A.; Schulze, R. E.; Simmonds, L. P.; Moriarty, P.; Mugabe, F.

1999-01-01

56

Mesoscale wind fluctuations over Danish waters  

Energy Technology Data Exchange (ETDEWEB)

Mesoscale wind fluctuations affect the large scale integration of wind power because they undermine the day-ahead predictability of wind speed and power production, and because they can result in large fluctuations in power generation that must be balanced using reserve power. Large fluctuations in generated power are a particular problem for offshore wind farms because the typically high concentration of turbines within a limited geographical area means that fluctuations can be correlated across large numbers of turbines. Furthermore, organised mesoscale structures that often form over water, such as convective rolls and cellular convection, have length scales of tens of kilometers, and can cause large wind fluctuations on a time scale of around an hour. This thesis is an exploration of the predictability of mesoscale wind fluctuations using observations from the world's first two large offshore wind farms - Horns Rev I in the North Sea, and Nysted in the Baltic Sea. The thesis begins with a climatological analysis of wind fluctuations on time scales of 1-10 hours at the two sites. A novel method for calculating conditional climatologies of spectral information is proposed, based on binning and averaging the time axis of the Hilbert spectrum. Results reveal clear patterns between wind fluctuations and locally observed meteorological conditions. The analysis is expanded by classifying wind fluctuations on time scales of 1-3 hours according to synoptic patterns, satellite pictures and wind classes. Results indicate that cold air outbreaks and open cellular convection are a significant contributor to mesoscale wind variability at Horns Rev. The predictability of mesoscale wind fluctuations is tested by implementing standard statistical models that relate local wind variability to parameters based on a large scale weather analysis. The models show some skill, but only achieve a 15% improvement on a persistence forecast. The possibility of explicitly modelling mesoscale fluctuations in a mesoscale model is then examined using the weather research and forecasting (WRF) model. A set of case studies demonstrate that realistic hour-scale wind fluctuations and open cellular convection patterns develop in WRF simulations with 2 km horizontal grid spacing. The atmospheric conditions during one of the case studies are then used to initialise a simplified version of the model that has no large scale weather forcing, topography or surface inhomogeneties. Using the simplified model, the sensitivity of the modelled open cellular convection to choices in model setup and to aspects of the environmental forcing are tested. Finally, the cell-scale kinetic energy budget of the modelled cells is calculated, and it is shown that the buoyancy and pressure balance terms are important for cell maintenance. It is explained that the representation of mesoscale convection in a mesoscale model is not only important to end users such as wind farm operators, but to the treatment of energy transport within the boundary layer. (Author)

Vincent, C.L.

2010-12-15

57

Hydrological processes and water resources management in a dryland environment IV: Long-term groundwater level fluctuations due to variation in rainfall  

Directory of Open Access Journals (Sweden)

Full Text Available To evaluate the effects of variations in rainfall on groundwater, long-term rainfall records were used to simulate groundwater levels over the period 1953-96 at an experimental catchment in south-east Zimbabwe. Two different modelling methods were adopted. Firstly, a soil water balance model (ACRU simulated drainage from daily rainfall and evaporative demand; groundwater levels were predicted as a function of drainage, specific yield and water table height. Secondly, the cumulative rainfall departure method was used to model groundwater levels from monthly rainfall. Both methods simulated observed groundwater levels over the period 1992-96 successfully, and long-term simulated trends in historical levels were comparable. Results suggest that large perturbations in groundwater levels area a normal feature of the response of a shallow aquifer to variations in rainfall. Long-term trends in groundwater levels are apparent and reflect the effect of cycles in rainfall. Average end of dry season water levels were simulated to be almost 3 m higher in the late 1970s compared to those of the early 1990s. The simulated effect of prolonged low rainfall on groundwater levels was particularly severe during the period 1981-92 with a series of low recharge years unprecedented in the earlier record. More recently, above average rainfall has resulted in generally higher groundwater levels. The modelling methods described may be applied in the development of guidelines for groundwater schemes to help ensure safe long-term yields and to predict future stress on groundwater resources in low rainfall periods; they are being developed to evaluate the effects of land use and management change on groundwater resources.

J. A. Butterworth

1999-01-01

58

Glacier fluctuations, global temperature and sea-level change  

OpenAIRE

The current world-wide glacier retreat is a clear sign of global warming. In addition, glaciers contribute to sea-level rise as a consequence of the current retreat. In this thesis we use records of past glacier fluctuations to reconstruct past climate variations and the glacier contribution to sea-level change. Firstly, a coherent data set of world-wide glacier fluctuations over the past centuries is compiled. Most available information of glacier fluctuations concerns glacier length flu...

Leclercq, P. W.

2012-01-01

59

Density fluctuations level during sawtooth relaxations in tokamak plasmas  

International Nuclear Information System (INIS)

Specific turbulence observed in TFR tokamak plasmas is discussed. The observations, performed by the analysis of density fluctuations with CO2 laser light scattering, were compared with the Andreoletti disruption model. The four phases of the specific fluctuation are presented. The specific turbulence level during the collapse, during the turbulent kink and the return phase are shown

60

Realistic quantum manipulation of two-level system fluctuators  

OpenAIRE

Two-level system fluctuators in superconducting devices have demonstrated coherent coupling with superconducting qubits. Here, we show that universal quantum logic gates can be realized in these two-level systems solely by tuning a superconducting resonator in which they are imbedded. Because of the large energy separation between the fluctuators, conventional gate schemes in the cavity QED approach that are widely used for solid-state qubits cannot be directly applied to th...

Tian, L.; Jacobs, K.

2009-01-01

61

Influence of two-level fluctuators on adiabatic passage techniques  

OpenAIRE

We study the process of Stimulated Raman Adiabatic Passage (STIRAP) under the influence of a non-trivial solid-state environment, particularly the effect of two-level fluctuators (TLFs) as they are frequently present in solid-state devices. When the amplitudes of the driving-pulses used in STIRAP are in resonance with the level spacing of the fluctuators the quality of the protocol, i.e., the transferred population decreases sharply. In general the effect can not be reduced ...

Vogt, Nicolas; Cole, Jared H.; Marthaler, Michael; Scho?n, Gerd

2012-01-01

62

Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake; Effects of Operation of Kerr and Hungry Horse Dam on Reproductive Success, 1983 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

Koktneesalmon (Oncorhvnchusnerka), the land-locked form of sockeye salmon, were originally introduced to Flathead Lake in 1916. My 1933, kokanee had become established in the lake and provided a popular summer trolling fishery as well as a fall snagging fishery in shoreline areas. Presently, Flathead Lake supports the second highest fishing pressure of any lake or reservoir in Montana (Montana Department of Fish and Game 1976). During 1981-82, the lake provided 168,792 man-days of fishing pressure. Ninety-two percent of the estimated 536,870 fish caught in Flathead Lake in 1981-82 were kokanee salmon. Kokanee also provided forage for bull trout seasonally and year round for lake trout. Kokanee rear to maturity in Flathead Lake, then return to various total grounds to spawn. Spawning occurred in lake outlet streams, springs, larger rivers and lake shoreline areas in suitable but often limited habitat. Shoreline spawning in Flathead Lake was first documented in the mid-1930's. Spawning kokanee were seized from shoreline areas in 1933 and 21,000 cans were processed and packed for distribution to the needy. Stefanich (1953 and 1954) later documented extensive but an unquantified amount of spawning along the shoreline as well as runs in Whitefish River and McDonald Creek in the 1950's. A creel census conducted in 1962-63 determined 11 to 13 percent of the kokanee caught annually were taken during the spawning period (Robbins 1966). During a 1981-82 creel census, less than one percent of the fishermen on Flathead Lake were snagging kokanee (Graham and Fredenberg 1982). The operation of Kerr Dam, located below Flathead Lake on the Flathead River, has altered seasonal fluctuations of Flathead Lake. Lake levels presently remain high during kokanee spawning in November and decline during the incubation and emergence periods. Groundwater plays an important role in embryo and fry survival in redds of shoreline areas exposed by lake drawdown. Stefanich (1954) and Domrose (1968) found live eggs and fry only in shoreline spawning areas wetted by groundwater seeps. Impacts of the operation of Kerr Dam on lakeshore spawning have not been quantified. Recent studies have revealed that operation of Hungry Horse Dam severely impacted successful kokanee spawning and incubation in the Flathead River above Flathead Lake (Graham et al. 1980, McMullin and Graham 1981, Fraley and Graham 1982 and Fraley and McMullin 1983). Flows from Hungry Horse Dam to enhance kokanee reproduction in the river system have been voluntarily met by the Bureau of Reclamation since 1981. In lakeshore spawning areas in other Pacific Northwest systems, spawning habitat for kokanee and sockeye salmon was characterized by seepage or groundwater flow where suitable substrate composition existed (Foerster 1968). Spawning primarily occurred in shallower depths (<6 m) where gravels were cleaned by wave action (Hassemer and Rieman 1979 and 1980, Stober et al. 1979a). Seasonal drawdown of reservoirs can adversely affect survival of incubating kokanee eggs and fry spawned in shallow shoreline areas. Jeppon (1955 and 1960) and Whitt (1957) estimated 10-75 percent kokanee egg loss in shoreline areas of Pend Oreille Lake, Idaho after regulation of the upper three meters occurred in 1952. After 20 years of operation, Bowler (1979) found Pend Oreille shoreline spawning to occur in fewer areas with generally lower numbers of adults. In studies on Priest Lake, Idaho, Bjornn (1957) attributed frozen eggs and stranded fry to winter fluctuations of the upper three meters of the lake. Eggs and fry frozen during winter drawdown accounted for a 90 percent loss to shoreline spawning kokanee in Donner Lake, California (Kimsey 1951). Stober et al. (1979a) determined irrigation drawdown of Banks Lake, Washington reduced shoreline survival during five of the seven years the system was studied. The goal of this phase of the study was to evaluate and document effects of the operation of Kerr Dam on kokanee shoreline reproduction in Flathead Lake. Specific objectives to meet this goal ar

Decker-Hess, Janet; McMullin, Steve L.

1983-11-01

63

Superstatistical analysis of sea-level fluctuations  

Science.gov (United States)

We perform a statistical analysis of measured time series of sea levels at various coastal locations in the UK, measured at time differences of 15 min over the past 20 years. When the astronomical tide and other deterministic components are removed from the record, a stochastic signal corresponding to the meteorological component remains, and this is well-described by a superstatistical model. We do various tests on the measured time series, and compare the data at 5 different UK locations. Overall the ?2-superstatistics is best suitable to describe the data, in particular when one looks at the dynamics of sea-level differences on short time scales.

Rabassa, Pau; Beck, Christian

2015-01-01

64

Fluctuations of water near extended hydrophobic and hydrophilic surfaces  

OpenAIRE

We use molecular dynamics simulations of the SPC-E model of liquid water to derive probability distributions for water density fluctuations in probe volumes of different shapes and sizes, both in the bulk as well as near hydrophobic and hydrophilic surfaces. Our results are obtained with a biased sampling of coarse-grained densities that is easily combined with molecular dynamics integration algorithms. Our principal result is that the probability for density fluctuations of water near a hydr...

Patel, Amish J.; Varilly, Patrick; Chandler, David

2009-01-01

65

Water Levels on the Great Lakes  

Science.gov (United States)

This resource explains that water levels are part of the ebb and flow of nature and the difference between the amount of water coming into a lake and the amount going out is the determining factor in whether the water level will rise, fall or remain stable. Students will learn that there are three types of water level fluctuations: short-term changes due to winds or changes in barometric pressure, seasonal changes depending on evaporation and precipitations, and long-term changes due to successive years of weather aberrations. Textual information is accompanied by graphs that illustrate these changes. The site also includes information about methods of measuring water levels and the economic impact of the changing levels.

66

Capillary effect on water table fluctuations in unconfined aquifers  

Science.gov (United States)

Parlange and Brutsaert (1987) derived a modified Boussinesq equation to account for the capillary effect on water table dynamics in unconfined aquifers. Barry et al. (1996) solved this equation subject to a periodic boundary condition. Their solution shows significant influence of capillarity on water table fluctuations, which evolve to finite-amplitude standing waves at the high frequency limit. Here we propose a new governing equation for the water table, which considers both horizontal and vertical flows in an unsaturated zone of finite thickness. An approximate analytical solution for periodic water table fluctuations based on the new equation was derived. In agreement with previous results, the analytical solution shows that the unsaturated zone's storage capacity permits water table fluctuations to propagate more readily than predicted by the Boussinesq equation. Furthermore, the new solution reveals a capping effect of the unsaturated zone on both the amplitude and phase of the water table fluctuations as well as the water table overheight. Due to the finite thickness of the unsaturated zone, the capillary effect on water table fluctuations is modified mainly with reduced amplitude damping and phase shift.

Kong, Jun; Shen, Cheng-Ji; Xin, Pei; Song, Zhiyao; Li, Ling; Barry, D. A.; Jeng, D.-S.; Stagnitti, F.; Lockington, D. A.; Parlange, J.-Y.

2013-05-01

67

Universality in level spacing fluctuations of a chaotic optical billiard  

International Nuclear Information System (INIS)

We study chaotic behavior of a classical optical stadium billiard model. We construct a matrix of time-of-travel along trajectories corresponding to a set of boundary points. We carry out a level spacing fluctuation analysis and compute the Dyson-Mehta spectral rigidity. The distribution of time-of-travel is approximately described by a Gaussian. The results for level spacing distribution and spectral rigidity show universal behavior.

68

Water level indicator  

International Nuclear Information System (INIS)

A difference of pressure between a standard pressure conduit in communication with a gas phase of a reactor pressure vessel and a water level pressure conduit in communication with a liquid phase of the pressure vessel is detected by a pressure difference gage. A communication pipe and a standard level vessel are disposed between the pressure vessel and the standard pressure conduit, and a standard liquid surface on the side of the standard pressure conduit is formed in the standard level vessel. A gas releaser is disposed to the gas phase portion of the standard level vessel. The gas releaser equipment is constituted by a porous material, a permeation membrane and a gas exhaustion hole. The gas phase of the standard level vessel is divided by a partition plate into a first gas phase being in contact with a connection portion with the communication pipe and a second gas phase in contact with the gas releaser. A gas flow channel hole and a condensate descending hole are disposed to the partition plate. Since incondensible gases accumulated to the standard level vessel are effectively exhausted, the incondensible gases are prevented from being dissolved into liquid. (I.N.)

69

Barotropic current fluctuations coupled with sea level drawdown in Yellow and Bohai Seas  

Science.gov (United States)

Sub-tidal barotropic current variations coupled with residual sea level fluctuation in the Bohai and Yellow Seas during wintertime are addressed in this study. The temporal evolution and spatial distribution of current fluctuation are investigated using moored acoustic Doppler current profiler data in a three-dimensional numerical model. It is found that a southward current followed by a northward current occurred in the northern Yellow Sea during the fluctuation, concurrent with a significant outflow followed by inflow through the Bohai Strait. The process is consistent from surface to bottom and is coupled with remarkable residual sea level fluctuation. This quasi three-day fluctuation with amplitude 0.2-0.3 m/s leads to 1 m/1.2 m drawdown in the northern Yellow and Bohai Seas, respectively, strongly influencing water exchange between those seas. Because this a prominent feature in the seas, it is necessary to evaluate its effect on fluctuation during winter in future studies, in particular, the northward current during the recovery phase of sea level in the Bohai and Yellow Seas regarding seasonal variation.

Wan, Kai; Bao, Xianwen; Wang, Yi; Wan, Xiuquan; Li, Haoqian; Liu, Ke

2015-01-01

70

Water level detection pipeline  

International Nuclear Information System (INIS)

In the present invention, water levels of a feedwater heater and a drain tank in a nuclear power plant are detected at high accuracy. Detection pipeline headers connected to the upper and lower portions of a feedwater heater or a drain tank are connected with each other. The connection line is branched at appropriate two positions and an upper detection pipeline and a lower detection pipeline are connected thereto, and a gauge entrance valve is disposed to each of the detection pipelines. A diaphragm of a pressure difference generator is connected to a flange formed to the end portion. When detecting the change of water level in the feedwater heater or the drain tank as a change of pressure difference, gauge entrance valves on the exit side of the upper and lower detection pipelines are connected by a connection pipe. The gauge entrance valve is closed, a tube is connected to the lower detection pipe to inject water to the diaphragm of the pressure difference generator passing through the connection pipe thereby enabling to calibrate the pressure difference generator. The accuracy of the calibration of instruments is improved and workability thereof upon flange maintenance is also improved. (I.S.)

71

Influence of two-level fluctuators on adiabatic passage techniques  

CERN Document Server

We study the effect of two-level fluctuators (TLFs), as they are frequently present in solid-state devices, on the process of Stimulated Raman Adiabatic Passage (STIRAP) performed with a quan- tum three-level system. When the amplitudes of the driving-pulses used in the STIRAP are in resonance with the level spacing of the fluctuators the quality of the protocol, i.e., the transferred population decreases sharply. In general the effect can not be reduced by speeding up the STIRAP process. We also discuss the effect of a structured noise environment on the process of Coherent Tunneling by Adiabatic Passage (CTAP). The effect of a weakly structured environment or TLFs with short coherence times on STIRAP and CTAP can be described by the Bloch-Redfield theory. For a strongly structured environment a higher-dimensional approach has to be used where the TLFs are treated as part of the system.

Vogt, Nicolas; Marthaler, Michael; Schön, Gerd

2012-01-01

72

GROUND WATER FLUCTUATIONS IN THE KANOLA WATERSHED BASIN OF KARMALA TAHSIL, SOLAPUR DISTRICT, MAHARASHTRA  

Directory of Open Access Journals (Sweden)

Full Text Available Water level fluctuations and depletion of the groundwater are the major problem in the drought prone area. Just deepening of well with heavy capital investment is not a proper solution. The problem is aggravated especially in the summer season. It has direct bearing on food security and poverty. The present study has attempted to understand fluctuations in the ground water levels in a Kanola watershed basin in the drought affected areas of Maharashtra state. The study concludes that it is necessary to undertake watershed development programmes in the basin taking into account specific site factors to ensure groundwater availability for longer period in a year.

PANDURANG Y. PATIL

2013-01-01

73

Experimental study of free level fluctuations in 1/4 scale reactor assembly model of PFBR  

International Nuclear Information System (INIS)

The construction pf Prototype Fast Breeder Reactor (PFBR), a 500 MWe liquid sodium cooled reactor has commenced at Kalpakkam in India. PFBR is a pool type reactor with two secondary loops. The primary sodium is contained within a 12.8 m diameter and 12.7 m high main vessel. The inner vessel separates the not and cold pools. The primary components like pumps, Control Plug, IHXs, DHXs, etc. are immersed in the reactor pool. Free level in the reactor pool is susceptible to fluctuations due to interaction of sodium stream from the core with the free surface and flow induced vortex shedding of the immersed structures like pump, IHX etc, in the hot pool. Due to free level fluctuations, the components immersed in sodium will alternately see hot sodium (at 820 k) and cooler argon cover gas) (at 670 K) at the sodium/argon interface. These temperature fluctuations can lead to thermal fatigue of the immersed components. Hence, it is required to assess the characteristics of free level fluctuations to understand their effect of the reactor components. In order to investigate various thermal hydraulic phenomena of PFBR, a large scale (1/4 scale) model of reactor primary circuit, which uses water as the working fluid, is constructed for experimental verification of thermal hydraulic behavior of the reactor. An experimental study was carried out in the above model to determine the magnitude and frequency of the free level fluctuations at different locations in the hot pool. The studferent locations in the hot pool. The study was conducted with Froude similitude. The free level fluctuations were measured using specially developed and calibrated conductivity probes. The experimental data were analyzed statistically. the model results were transposed to the reactor condition using appropriate similarity laws. It was observed that the free level fluctuations are not uniform in the hot pool and vary at different locations in the pool. The minimum peak-to-peak amplitude of fluctuations is about 38 mm at different locations if the pool. the minimum peak-to-peak amplitude of fluctuations is about 38 mm near the IHX and maximum is 82 mm in the vicinity of the control Plug for nominal operating conditions. The frequency of fluctuations was found to be less than 1.5 Hz. This paper brings out the details of the model, similarity criteria for the studies, instrumentation involved and the analysis of results obtained. (author)

74

Masker fluctuation and the masking-level difference.  

Science.gov (United States)

Previous work suggests that, for some listeners, masker fluctuation may be advantageous for NoS pi detection. This study tested the hypothesis that the benefit of masker fluctuation to binaural analysis is based on the ability to take advantage of epochs of low masker energy in the fluctuating masker where the cues underlying binaural signal detection are more salient. The hypothesis was evaluated using the time-domain version of COSS analysis derived by Buus et al. [J. Acoust. Soc. Am. 99, 2288-2297 (1996)] which measures the perceptual weight applied by a listener within a relatively brief time window as a function of the masker level during the window. The results indicated a dependency of signal detection on short-term masker level in the NoS pi condition but not in the NoSo condition. This finding supports a new perspective indicating that binaural signal detection depends upon the envelope of a masker in a way that is fundamentally different from that typically associated with monaural detection. PMID:9604353

Grose, J H; Hall, J W

1998-05-01

75

Characterization of the level fluctuations in a physical model of the steel continuous casting mold through image processing  

Directory of Open Access Journals (Sweden)

configuration resembles a perfect control of the liquid level inside the water model. A high-speed video camera was used to get several video clips of the movement of the water level profile. Several techniques were tested in order to obtain the best lighting conditions for recording the water movement. The edge-detection technique of Sobel was used to determine the profile of the liquid level in each one of the images recorded. The analysis of the dynamic behavior of the water profile showed that the fluctuations of the liquid level inside the mold have a complex structure, which is repeated over large time periods.

J.R. Miranda-Tello

2012-01-01

76

High levels of fluctuating asymmetry in isolated stickleback populations  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Fluctuating asymmetry (FA, defined as small random deviations from the ideal bilateral symmetry, has been hypothesized to increase in response to both genetic and environmental stress experienced by a population. We compared levels of FA in 12 bilateral meristic traits (viz. lateral-line system neuromasts and lateral plates, and heterozygosity in 23 microsatellite loci, among four marine (high piscine predation risk and four pond (zero piscine predation risk populations of nine-spined sticklebacks (Pungitius pungitius. Results Pond sticklebacks had on average three times higher levels of FA than marine fish and this difference was highly significant. Heterozygosity in microsatellite markers was on average two times lower in pond (HE ? 0.3 than in marine (HE ? 0.6 populations, and levels of FA and heterozygosity were negatively correlated across populations. However, after controlling for habitat effect on heterozygosity, levels of FA and heterozygosity were uncorrelated. Conclusions The fact that levels of FA in traits likely to be important in the context of predator evasion were elevated in ponds compared to marine populations suggests that relaxed selection for homeostasis in ponds lacking predatory fish may be responsible for the observed habitat difference in levels of FA. This inference also aligns with the observation that the levels of genetic variability across the populations did not explain population differences in levels of FA after correcting for habitat effect. Hence, while differences in strength of selection, rather than in the degree of genetic stress could be argued to explain habitat differences in levels of FA, the hypothesis that increased FA in ponds is caused by genetic stress cannot be rejected.

Trokovic Nina

2012-07-01

77

Level density of a Fermion gas: average growth, fluctuations, universality  

International Nuclear Information System (INIS)

It has been shown by H. Bethe more than 70 years ago that the number of excited states of a Fermi gas grows, at high excitation energies Q, like the exponential of the square root of Q. This result takes into account only the average density of single particle (SP) levels near the Fermi energy. It ignores two important effects, namely the discreteness of the SP spectrum, and its fluctuations. We show that the discreteness of the SP spectrum gives rise to smooth finite-Q corrections. Mathematically, these corrections are associated to the problem of partitions of an integer. On top of the smooth growth of the many-body density of states there are, generically, oscillations. An explicit expression of these oscillations is given. Their properties strongly depend on the regular or chaotic nature of the SP motion. In particular, we analyze their typical size, temperature dependence and probability distribution, with emphasis on their universal aspects

78

Level density of a Fermion gas: average growth, fluctuations, universality  

Science.gov (United States)

It has been shown by H. Bethe more than 70 years ago that the number of excited states of a Fermi gas grows, at high excitation energies Q, like the exponential of the square root of Q. This result takes into account only the average density of single particle (SP) levels near the Fermi energy. It ignores two important effects, namely the discreteness of the SP spectrum, and its fluctuations. We show that the discreteness of the SP spectrum gives rise to smooth finite-Q corrections. Mathematically, these corrections are associated to the problem of partitions of an integer. On top of the smooth growth of the many-body density of states there are, generically, oscillations. An explicit expression of these oscillations is given. Their properties strongly depend on the regular or chaotic nature of the SP motion. In particular, we analyze their typical size, temperature dependence and probability distribution, with emphasis on their universal aspects.

Leboeuf, P.

2005-07-01

79

Level density of a Fermion gas: average growth, fluctuations, universality  

CERN Document Server

It has been shown by H. Bethe more than 70 years ago that the number of excited states of a Fermi gas grows, at high excitation energies $Q$, like the exponential of the square root of $Q$. This result takes into account only the average density of single particle (SP) levels near the Fermi energy. It ignores two important effects, namely the discreteness of the SP spectrum, and its fluctuations. We show that the discreteness of the SP spectrum gives rise to smooth finite--$Q$ corrections. Mathematically, these corrections are associated to the problem of partitions of an integer. On top of the smooth growth of the many--body density of states there are, generically, oscillations. An explicit expression of these oscillations is given. Their properties strongly depend on the regular or chaotic nature of the SP motion. In particular, we analyze their typical size, temperature dependence and probability distribution, with emphasis on their universal aspects.

Leboeuf, P

2005-01-01

80

[Using ultraviolet-visible ( UV-Vis) absorption spectrum to estimate the dissolved organic matter (DOM) concentration in water, soils and sediments of typical water-level fluctuation zones of the Three Gorges Reservoir areas].  

Science.gov (United States)

Dissolved organic matter (DOM) is a very important component in terrestrial ecosystem. Chromophoric dissolved organic matter (CDOM) is a significant constituent of DOM, which can be measured by ultraviolet-visible (UV-Vis) absorption spectrum. Thus the relationship between CDOM and DOM was investigated and established by several types of models including single-wavelength model, double-wavelength model, absorption spectrum slope (S value) model and three-wavelength model, based on the UV-Vis absorption coefficients of soil and sediment samples (sampled in July of 2012) and water samples (sampled in November of 2012) respectively. The results suggested that the three-wavelength model was the best for fitting, and the determination coefficients of water, soil and sediment data were 0. 788, 0. 933 and 0. 856, respectively. Meanwhile, the nominal best model was validated with the UV-Vis data of 32 soil samples and 36 water samples randomly collected in 2013, showing the RRMSE and MRE were 16. 5% and 16. 9% respectively for soil DOM samples, 10. 32% and 9. 06% respectively for water DOM samples, which further suggested the prediction accuracy was higher in water DOM samples as compared with that in soil DOM samples. PMID:25518658

Li, Lu-lu; Jiang, Tao; Lu, Song; Yan, Jin-long; Gao, Jie; Wei, Shi-qiang; Wang, Ding-yong; Guo, Nian; Zhao, Zhena

2014-09-01

81

Predicting groundwater level fluctuations with meteorological effect implications—A comparative study among soft computing techniques  

Science.gov (United States)

The knowledge of groundwater table fluctuations is important in agricultural lands as well as in the studies related to groundwater utilization and management levels. This paper investigates the abilities of Gene Expression Programming (GEP), Adaptive Neuro-Fuzzy Inference System (ANFIS), Artificial Neural Networks (ANN) and Support Vector Machine (SVM) techniques for groundwater level forecasting in following day up to 7-day prediction intervals. Several input combinations comprising water table level, rainfall and evapotranspiration values from Hongcheon Well station (South Korea), covering a period of eight years (2001-2008) were used to develop and test the applied models. The data from the first six years were used for developing (training) the applied models and the last two years data were reserved for testing. A comparison was also made between the forecasts provided by these models and the Auto-Regressive Moving Average (ARMA) technique. Based on the comparisons, it was found that the GEP models could be employed successfully in forecasting water table level fluctuations up to 7 days beyond data records.

Shiri, Jalal; Kisi, Ozgur; Yoon, Heesung; Lee, Kang-Kun; Hossein Nazemi, Amir

2013-07-01

82

Low level activity determination by means of gamma spectrometry with respect to the natural background fluctuation  

International Nuclear Information System (INIS)

The determination of low level activities of natural radionuclides from the uranium and thorium series by gamma-spectrometry faces the problem of proper natural background subtraction. Background fluctuation can cause differences in activity determination. Also the minimum detectable activity (MDA) of natural and artificial radionuclides can be influenced by background fluctuation. In this paper, results of the background fluctuation of shielded HPGe detectors with relative efficiency of 50–150% are presented together with the assessment of its influence on the determination of natural and artificial radionuclides. - Highlights: • Long term study of background peaks and integral counts. • Background fluctuation cause differences in low level activity determination. • Background fluctuation influence MDA calculation

83

Structural Fluctuation of Protein in Water around Its Native State: A New Statistical Mechanics Formulation  

CERN Document Server

A new statistical mechanics formulation of characterizing the structural fluctuation of protein correlated with that of water is presented based on the generalized Langevin equation and the 3D-RISM/RISM theory of molecular liquids. The displacement vector of atom positions and their conjugated momentum, are chosen for the dynamic variables for protein, while the density fields of atoms and their momentum fields are chosen for water. Projection of other degrees of freedom onto those dynamic variables using the standard projection operator method produces essentially two equations which describe the time evolution of fluctuation concerning the density field of solvent and the conformation of protein around an equilibrium state, which are coupled with each other. The equation concerning the protein dynamics is formally akin to that of the coupled Langevin oscillators, and is a generalization of the latter, to atomic level. The most intriguing feature of the new equation is that it contains the variance-covarianc...

Kim, Bongsoo

2012-01-01

84

Response of groundwater to climate variation: fluctuations of groundwater level and well yields in the Halacli aquifer (Cankiri, Turkey).  

Science.gov (United States)

The aim of this study was to investigate the response of groundwater level and well yields in the Halacli aquifer to climate variations in Central Anatolia, Turkey. The Halacli aquifer is a typical aquifer due to its vulnerability to the climate variations. The aquifer is shallow and its recharge area is small. The waters from rains and snow melts can rapidly infiltrate down to the groundwater body because the vadose zone is thin and formed from coarse material. Therefore, the groundwater system responds to the short-term recharges by raising its level. Although any exploitation did not occur, the groundwater levels have declined from 1989 to 1997. However, the groundwater levels began rising when the exploitation started in the summer of 1998. After the year 2000, although the amount and duration of yearly exploitation was constant, fluctuations of water level continued. Fluctuation of groundwater levels and well yields bewilders the water users and imperils the sustainable water management in the study area and also in arid and semi-arid regions of Turkey. In order to overcome this problem, behavior of groundwater level and discharges of the wells must be recorded and the water users must be informed about the current conditions and the possible trend in the future of the system. PMID:19472066

Apaydin, Ahmet

2010-06-01

85

Reactor water level control device  

International Nuclear Information System (INIS)

Purpose: To avoid the generation of abnormal impulse noises upon switching between single factor control for the detection of reactor water level and three factor control for the detection of reactor water level, feedwater rate and main steam rate. Constitution: Switching circuit has a contact actuated in response to the operation of a control system turning switch. The contact is opened for the single factor control and closed for the three factor control. Values for the detected main steam flow rate and feedwater flow rate are connected by way of a second adder and a coefficient multiplier to the input of the switching circuit to thereby input the deviation as a correction signal. While on the other hand, the output of the switching circuit is connected to the input of a third adder. A set value for the feedwater flow rate and a detection signal are connected by way of a first adder to the input of the above adder. This causes the deviation signal in the reactor water level to be inputted directly with no effects from the switching circuit. The output of the adder is inputted directly to a PI adjusting circuit having proportionating and integrating functions. (Kawakami, Y.)

86

Hall Voltage Fluctuations as a Diagnostic of Internal Magnetic Field Fluctuations in High Temperature Superconductors and the Half-filled Landau Level  

OpenAIRE

Fluctuations of the Hall voltage reveal information about long wavelength magnetic field fluctuations. If gauge theories of strongly correlated electrons are correct, such fluctuations are particularly large in the half-filled Landau level and in high $T_c$ superconductors. We present estimates for the magnitude, system size and frequency dependence of these fluctuations. The frequency dependence contains information about instantons in the gauge field.

Ioffe, L. B.; Lesovik, G. B.; Millis, A. J.

1996-01-01

87

Convective amplification of drift waves and thermal fluctuation levels in a stable plasma  

International Nuclear Information System (INIS)

The possibility that convective amplification of drift waves gives rise to significant thermal fluctuation levels in a stable tokamak plasma is investigated. A test particle formulation yields a differential dispersion equation, which is amenable to numerical solution. It is found that, for realistic tokamak parameters, the calculated thermal fluctuation levels are far below those measured experimentally. Convective amplifications are localized and relatively small. The largest calculated fluctuation levels are due to an enhancement of the thermal source strength for frequencies near the eigenfrequencies of weakly damped normal modes

88

Water level influences on body condition of Geophagus brasiliensis (Perciformes: Cichlidae) in a Brazilian oligotrophic reservoir  

OpenAIRE

Effects of water level fluctuations on body condition of Geophagus brasiliensis were studied in a 30 km² Brazilian oligotrophic reservoir. Physiological condition (K) and gonadosomatic index (GSI) were compared according to water level (low and high). Females' best conditions were associated to higher resources availability during high water, since gonad development did not change between low and high water. Males' condition did not change between water levels, while the highest gonad develo...

Alejandra Filippo Gonzalez Neves dos Santos; Luciano Neves dos Santos; Francisco Gerson Araújo

2004-01-01

89

Method of controlling water level in reactor  

International Nuclear Information System (INIS)

Purpose: To enable continual retention of water level in a nuclear reactor to specified value. Method: When a water level in a reactor reaches a predetermined high-water-level setting point or low-water-level setting point, drain amount necessary for returning to an ordinary water level and drain amount necessary for maintaining the water level are calculated by a computer, the opening-degree of a drain control valve is calculated with a deviation between the drain amount thus calculated and the drain amount actually measured, thereby always maintaining the water level at the specified range. (Yoshihara, H.)

90

Investigation of free level fluctuations in a simulated model of a sodium cooled Fast Breeder Reactor using pulsating conductance monitoring device  

International Nuclear Information System (INIS)

Highlights: ? An innovative approach for measurement of water level fluctuation is presented. ? Measurement was conducted with a PC based pulsating type level sensor. ? Deployed the technique in monitoring level fluctuation in PFBR simulated facility. ? The technique helped in validation of hot pool design of PFBR, India. - Abstract: A high resolution measurement technique for rapid and accurate monitoring of water level using an in-house built pulsating conductance monitoring device is presented. The technique has the capability of online monitoring of any sudden shift in water level in a reservoir which is subjected to rapid fluctuations due to any external factor. We have deployed this novel technique for real time monitoring of water level fluctuations in a specially designed ¼ scale model of the Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, India. The water level measurements in various locations of the simulated test facility were carried out in different experimental campaigns with and without inclusion of thermal baffles to it in specific operating conditions as required by the reactor designers. The amplitudes and the frequencies of fluctuations with required statistical parameters in hot water pool of the simulated model were evaluated from the online time versus water level plot in more convenient way using system software package. From experimental results it is computed that the maximum free level fluctuation in the hot pool of PFBR with ban in the hot pool of PFBR with baffle plates provided on the inner vessel is 30 mm which is considerably less than the value (?82 mm) obtained without having any baffle plates. The present work provided useful information for assessment of appropriate design which would be adopted in the PFBR for safe operation of the reactor.

91

Why is the CMB fluctuation level 10^{-5}?  

OpenAIRE

We explore the qualitative changes that would occur if the amplitude Q ~ 10^{-5} of cosmological density fluctuations were different. If is less than about 10^{-6}, the cosmological objects that form would have so low virial temperatures that they may be unable to cool and form stars, and would be so loosely bound that even if they could produce a supernova explosion, they might be unable to retain the heavy elements necessary for planetary life. If Q is greater than about 1...

Tegmark, Max; Rees, Martin

1997-01-01

92

A field investigation of phreatophyte-induced fluctuations in the water table  

Science.gov (United States)

Hydrographs from shallow wells in vegetated riparian zones frequently display a distinctive pattern of diurnal water table fluctuations produced by variations in plant water use. A multisite investigation assessed the major controls on these fluctuations and the ecohydrologic insights that can be gleaned from them. Spatial and temporal variations in the amplitude of the fluctuations are primarily a function of variations in (1) the meteorological drivers of plant water use, (2) vegetation density, type, and vitality, and (3) the specific yield of sediments in the vicinity of the water table. Past hydrologic conditions experienced by the riparian zone vegetation, either in previous years or earlier within the same growing season, are also an important control. Diurnal water table fluctuations can be considered a diagnostic indicator of groundwater consumption by phreatophytes at most sites, so the information embedded within these fluctuations should be more widely exploited in ecohydrologic studies. Copyright 2007 by the American Geophysical Union.

Butler, J.J., Jr.; Kluitenberg, G.J.; Whittemore, D.O.; Loheide, S.P., II; Jin, W.; Billinger, M.A.; Zhan, X.

2007-01-01

93

Sea-level fluctuations in the fleet, an English tidal lagoon  

Science.gov (United States)

Tidal elevation data are presented for places along the length of the Fleet, which is a tidal lagoon behind Chesil Beach on the south coast of England. Harmonic analysis of the data is not able to represent the observations adequately, particularly at the inner end of the lagoon. However, careful inspection of the data shows that the tidal regime is capable of being understood in terms of the non-linear propagation of long waves in very shallow water. Distortion of the tidal wave by unequal progression speeds of high and low water, and the set-up of mean level by frictional effects, are shown to be the important physical mechanisms controlling the observed water level fluctuations. A one-dimensional numerical model which incorporates these processes is able to reproduce the observations satisfactorily. Whilst the model predicts strong effects of wind stress, the meteorological influences in the observed data appear to be largely due to external surges in the English Channel which propagate into the lagoon through its entrance.

Robinson, I. S.; Warren, L.; Longbottom, J. F.

1983-06-01

94

Reactor water level measuring device  

International Nuclear Information System (INIS)

The device of the present invention can measure an accurate reactor water level even upon rapid and great depressurization of a reactor as well as during normal operation. Namely, a gas exhaustion channel is disposed in a condensation vessel to exhaust an incondensible gas in the coagulation vessel to a main steam pipeline, thereby preventing accumulation or dissolution of the incondensible gas in the coagulation vessel. For example, a vent tube is disposed between a gas phase portion of the coagulation vessel and the main steam pipeline connected to a reactor pressure vessel for communicating them. This always exhausts oxygen or hydrogen from the coagulation vessel by way of the vent tube. Accordingly, this reduces accumulation of oxygen or hydrogen in the coagulation vessel to elevate the pressure thereby hindering flow of steams from the reactor pressure vessel or dissolution into condensates. As a result, the change of the reference water level in the coagulation vessel is suppressed even upon rapid and great depressurization in the reactor pressure vessel, to improve accuracy of reactor water signals from a differential pressure detector. (I.S.)

95

Beach water table fluctuations due to wave run-up: Capillarity effects  

Science.gov (United States)

High-frequency beach water table fluctuations due to wave run-up and run-down have been observed in the field [Waddell, 1976]. Such fluctuations affect the infiltration/exfiltration process across the beach face and the interstitial oxygenation process in the beach ecosystem. Accurate representation of high-frequency water table fluctuations is of importance in the modeling of (1) the interaction between seawater and groundwater, more important, the effects on swash sediment transport and (2) the biological activities in the beach ecosystem. Capillarity effects provide a mechanism for high-frequency water table fluctuations. Previous modeling approaches adopted the assumption of saturated flow only and failed to predict the propagation of high-frequency fluctuations in the aquifer. In this paper we develop a modified kinematic boundary condition (kbc) for the water table which incorporates capillarity effects. The application of this kbc in a boundary element model enables the simulation of high-frequency water table fluctuations due to wave run-up. Numerical tests were carried out for a rectangular domain with small-amplitude oscillations; the behavior of water table responses was found to be similar to that predicted by an analytical solution based on the one-dimensional Boussinesq equation. The model was also applied to simulate the water table response to wave run-up on a sloping beach. The results showed similar features of water table fluctuations observed in the field. In particular, these fluctuations are standing wave-like with the amplitude becoming increasingly damped inland. We conclude that the modified kbc presented here is a reasonable approximation of capillarity effects on beach water table fluctuations. However, further model validation is necessary before the model can confidently be used to simulate high-frequency water table fluctuations due to wave run-up.

Li, L.; Barry, D. A.; Parlange, J.-Y.; Pattiaratchi, C. B.

1997-05-01

96

Forecasting Groundwater Level Fluctuations In a Costal Aquifer Using Support Vector Machine  

Science.gov (United States)

Precise prediction of groundwater level fluctuations has been an important and challenging topic in hydrology. In coastal aquifer the groundwater level is influenced by a tide level as well as a precipitation, which renders the prediction more difficult. Support vector machine (SVM), a novel data-driven and artificial intelligence-based model, shows remarkable prediction performances for non-linear systems in many disciplines. Recently, researches using SVM for the prediction of water resource variables are increasing. In this study we developed a SVM based time series model, then we applied it to forecasting the groundwater level at the coastal aquifer of Mangsang in the western side of East Sea, Korea. We especially focused upon assessing the influence of input vector organizations on model performances. The results show that input vectors including past data of the groundwater level raise the model performance notably, with correlation coefficient over 0.9 in this case. This model performance is comparable or even superior to that of artificial neural network models or linear time series models. Sensitivity analyses for input vector sizes and prediction lag times emphasize that the input vector organization is necessary for a SVM time series model application to hydrologic fields.

Yoon, H.; Jun, S.; Lee, K.

2007-12-01

97

Effect of water table fluctuations on phreatophytic root distribution.  

Science.gov (United States)

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. PMID:25014476

Tron, Stefania; Laio, Francesco; Ridolfi, Luca

2014-11-01

98

Using Reverse Water Levels to Characterize Fractured-Rock Aquifers  

Science.gov (United States)

Reverse water-level fluctuations have been widely observed in aquitards or aquifers separated from a pumped confined aquifer (Noordbergum effect) immediately after the initiation of pumping. This same reverse fluctuation has been observed in a fractured crystalline-rock aquifer at the Coles Hill Uranium site in Virginia in which the reverse water-level response occurs within the pumped fracture (Mandel-Cryer effect) and results from an instantaneous strain response to pumping that supersedes the pore-pressure response in observation wells of sufficient distance from the pumped well. The unique aspect of this water level rise during a controlled 24 hour pumping test was that the reverse water levels lasted for approximately 100 minutes and reached a magnitude of nearly 1 cm prior to a typical drawdown response. The duration and magnitude of the response reflects the poromechanical properties of the fractured host rock and hydraulic properties of the pumped fracture. A flow and deformation model was developed using Abaqus in an effort to simulate the observed water-level response along a horizontal fracture 176 m from the pumping well and to identify the importance of the poroelastic response. Simulation results indicate that traditional aquifer-testing methods that ignore the poromechanical response underestimate the fracture conductivity by a factor of 15. The results show that the strain response initiating the reverse water-level fluctuation is an important diagnostic tool that provides valuable information about the hostrock environment that cannot be obtained by analysis of traditional drawdown curves in fractured media.

Burbey, T. J.

2011-12-01

99

The effect of pressurizer-water-level on the low frequency component of the pressure spectrum in a PWR  

International Nuclear Information System (INIS)

The pressure fluctuations were measured in the cooling system of the Paks-1 reactor. A shift of the peak was detected in low frequency component of the pressure fluctuation spectrum which is due to the fluctuations of water level in the pressurizer. Using the model of Katona and Nagy (1983), the eigenfrequencies, the magnitude of the shift and the sensitivity to the pressurizer water level were reproduced in good accordance with the experimental data. (D.Gy.)

100

Effects of a long term water level reduction on the ecology and water quality in an eastern Mediterranean lake  

OpenAIRE

Water level fluctuations play a significant role in the lake nutrient dynamics, and consequently may have a strong influence on the biological communities and productivity. In this article we investigated the effects of a long term water level reduction on key chemistry parameters and major biological communities in an eastern Mediterranean lake. Our approach is based on temporal data regarding water quality, fish, zooplankton and aquatic vegetation that are representative of different water ...

Stefanidis K.; Papastergiadou E.

2013-01-01

101

Monitoring device for reactor water level  

International Nuclear Information System (INIS)

Purpose: To improve the reliability in the reactor water level monitoring by estimating the reactor water level in an abnormal transient state and thereby forecast the water level response in a BWR type nuclear power plant. Constitution: Main process parameters (main steam flow rate, feedwater flow rate, reactor water level and reactor pressure) for a nuclear power plant are taken into an input device. An estimation device for actual reactor water level estimates an actual reactor water level based on these parameter data. If the detection range for a reactor water level detector is exceeded, it is judged by a judging device for reactor water level indication and the estimated value is employed for the monitoring of the reactor water level. The output from an estimation device for actual water level variation coefficient and an estimation value for actual reactor water level variation coefficient prepared by integrating the above output with time are inputted into a forecasting calculator for reactor water level response and the calculator outputs a forecast value for reactor water level response as a time function. (Seki, T.)

102

Cosine components in water levels at Yucca Mountain  

International Nuclear Information System (INIS)

Water-level records from wells at Yucca Mountain, Nevada are analyzed periodically to determine if they contain periodic (cosine) components. Water-level data from selected wells are input to an iterative numerical procedure that determines a best fitting cosine function. The available water-level data, with coverage of up to 5 years, appear to be representative of the natural water-level changes. From our analysis of 9 water-level records, it appears that there may be periodic components (periods of 2-3 years) in the groundwater-level fluctuations at Yucca Mountain, Nevada, although some records are fit better than others by cosine functions. It also appears that the periodic behavior has a spatial distribution. Wells west of Yucca Mountain have different periods and phase shifts from wells on and east of Yucca Mountain. Interestingly, a similar spatial distribution of groundwater chemistry at Yucca Mountain is reported by Matuska (1988). This suggests a physical cause may underlie the different physical and chemical groundwater conditions. Although a variety of natural processes could cause water-level fluctuations, hydrologic processes are the most likely, because the periodicities are only a few years. A possible cause could be periodic recharge related to a periodicity in precipitation. It is interesting that Cochran et al., (1988), show a crude two-year cycle of precipitation for 1961 to 1970 in southern Nevada. Why periods and phase shifts may differ across Yucods and phase shifts may differ across Yucca Mountain is unknown. Different phase shifts could indicate different lag times of response to hydrologic stimuli. Difference in periods could mean that the geologic media is heterogeneous and displays heterogeneous response to a single stimulus, or that stimuli differ in certain regions, or that a hydraulic barrier separates the groundwater system into two regions having different water chemistry and recharge areas. 13 refs., 5 figs., 1 tab

103

The fluctuations of Lago Maggiore levels in a regulated regime consideration on low water events (Le fluttuazioni di livello del Lago Maggiore in regime regolato: considerazioni sugli eventi di magra)  

OpenAIRE

Lago Maggiore, due to the elevation and morphological nature of its drainage basin and to its location in a high precipitation climatic zone with a great inter-annual variability, is a water body with a high hydrogeological risk in that it is subject to floods and low water episodes that can be long-lasting. This last aspect, rather neglected in the previous studies, poses a serious risk for the communities on the shoreline and also for the use of the water resources for the irrigation of a w...

Barbanti, Luigi; Ambrosetti, Walter; Rolla, Angelo

2007-01-01

104

Water Density Fluctuations Relevant to Hydrophobic Hydration are Unaltered by Attractions  

CERN Document Server

An understanding of density fluctuations in bulk water has made significant contributions to our understanding of the hydration and interactions of idealized, purely repulsive hydrophobic solutes. To similarly inform the hydration of realistic hydrophobic solutes that have dispersive interactions with water, here we characterize water density fluctuations in the presence of attractive fields that correspond to solute-water attractions. We find that when the attractive field acts only in the solute hydration shell, but not in the solute core, it does not significantly alter water density fluctuations in the solute core region. We further find that for a wide range of solute sizes and attraction strengths, the free energetics of turning on the attractive fields in bulk water are accurately captured by linear response theory. Our results also suggest strategies for more efficiently estimating hydration free energies of realistic solutes in bulk water and at interfaces.

Remsing, Richard C

2014-01-01

105

Water density fluctuations relevant to hydrophobic hydration are unaltered by attractions  

Science.gov (United States)

An understanding of density fluctuations in bulk water has made significant contributions to our understanding of the hydration and interactions of idealized, purely repulsive hydrophobic solutes. To similarly inform the hydration of realistic hydrophobic solutes that have dispersive interactions with water, here we characterize water density fluctuations in the presence of attractive fields that correspond to solute-water attractions. We find that when the attractive field acts only in the solute hydration shell, but not in the solute core, it does not significantly alter water density fluctuations in the solute core region. We further find that for a wide range of solute sizes and attraction strengths, the free energetics of turning on the attractive fields in bulk water are accurately captured by linear response theory. Our results also suggest strategies for more efficiently estimating hydration free energies of realistic solutes in bulk water and at interfaces.

Remsing, Richard C.; Patel, Amish J.

2015-01-01

106

A causal model for fluctuating sugar levels in diabetes patients  

OpenAIRE

Background Causal models of physiological systems can be immensely useful in medicine as they may be used for both diagnostic and therapeutic reasoning. Aims In this paper we investigate how an agent may use the theory of belief change to rectify simple causal models of changing blood sugar levels in diabetes patients. Method We employ the semantic approach to belief change together with a popular measure of distance called Dalal distance between different state descriptions in order to imple...

Kinzang Chhogyal; Abhaya Nayak; Rolf Schwitter; Abdul Sattar

2012-01-01

107

Characterization of the level fluctuations in a physical model of the steel continuous casting mold through image processing  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in english In this work is characterized the periodic behavior of the liquid level inside a scaled cold-model of the mold section of a steel continuous casting machine, which uses water as working fluid. The models are designed in order to simulate the dynamic forces acting on the molten steel inside a mold of [...] continuous casting. The force magnitude can induce choppy flow, waves and vortex formation in the mold. The experimental model uses a closed-loop hydraulic configuration. In the mold, the inlet and the outlet water flow rates are the same. This configuration resembles a perfect control of the liquid level inside the water model. A high-speed video camera was used to get several video clips of the movement of the water level profile. Several techniques were tested in order to obtain the best lighting conditions for recording the water movement. The edge-detection technique of Sobel was used to determine the profile of the liquid level in each one of the images recorded. The analysis of the dynamic behavior of the water profile showed that the fluctuations of the liquid level inside the mold have a complex structure, which is repeated over large time periods.

J.R., Miranda-Tello; F., Sánchez-Rangel; C.A., Real-Ramírez; G., Khatchatourov; J.A., Aragón-Lezama; L.F., Hoyos-Reyes; E.A., Andrade-González; J.I., González-Trejo.

2012-04-01

108

Fluctuations of resonance-fluorescence intensity when resonating-level hyperfine structure is available  

International Nuclear Information System (INIS)

Consideration is given to expression, derived for correlation function of intensity fluctuations in the spectrum of resonance fluorescence of solitary atoms in the presence of hyperfine structure of resonating levels, in the case when stark level splitting exceeds sufficiently the intervals of hyperfine structure. Calculations are conducted in the basis of quasienergy states

109

Temporal scaling of groundwater level fluctuations near a stream.  

Science.gov (United States)

Temporal scaling in stream discharge and hydraulic heads in riparian wells was evaluated to determine the feasibility of using spectral analysis to identify potential surface and groundwater interaction. In floodplains where groundwater levels respond rapidly to precipitation recharge, potential interaction is established if the hydraulic head (h) spectrum of riparian groundwater has a power spectral density similar to stream discharge (Q), exhibiting a characteristic breakpoint between high and low frequencies. At a field site in Walnut Creek watershed in central Iowa, spectral analysis of h in wells located 1 m from the channel edge showed a breakpoint in scaling very similar to the spectrum of Q (?20 h), whereas h in wells located 20 and 40 m from the channel showed temporal scaling from 1 to 10,000 h without a well-defined breakpoint. The spectral exponent (?) in the riparian zone decreased systematically from the channel into the floodplain as groundwater levels were increasingly dominated by white noise groundwater recharge. The scaling pattern of hydraulic head was not affected by land cover type, although the number of analyses was limited and site conditions were variable among sites. Spectral analysis would not replace quantitative tracer or modeling studies, but the method may provide a simple means of confirming potential interaction at some sites. PMID:21352211

Schilling, Keith E; Zhang, You-Kuan

2012-01-01

110

Changes in climate, catchment vegetation and hydrogeology as the causes of dramatic lake-level fluctuations in the Kurtna Lake District, NE Estonia  

OpenAIRE

Numerous lakes in the world serve as sensitive indicators of climate change. Water levels for lakes Ahnejärv and Martiska, two vulnerable oligotrophic closed-basin lakes on sandy plains in northeastern Estonia, fell more than 3 m in 1946–1987 and rose up to 2 m by 2009. Earlier studies indicated that changes in rates of groundwater abstraction were primarily responsible for the changes, but scientifically sound explanations for water-level fluctuations were still lacking. Despite the inc...

Marko Vainu; Jaanus Terasmaa

2014-01-01

111

Water level detector for BWR type reactor  

International Nuclear Information System (INIS)

Purpose: To accurately detect the water level of reactor irrespective of the reactor water flow velocity. Constitution: A total pressure detecting port is opened at the upstream side of the reactor water flowing direction in a BWR type reactor, and the water level is detected from the differential pressure between the total pressure detected at the total pressure detecting port and a reference head pressure. Or, a total pressure detecting port and a static pressure detecting port are provided, static and dynamic pressures are thus separately detected, converted into electric signals, corrected and added, a signal corresponding to the differential pressure between the total pressure and the reference head pressure is thus obtained, and the water level is detected with the signal. Accordingly, the water level can be accurately obtained regardless of the reactor water flow velocity, the dynamic pressure having a relatively large error can be corrected, and the water level can be detected more accurately. (Yoshihara, H.)

112

A Causal Model for Fluctuating Sugar Levels in Diabetes Patients  

Directory of Open Access Journals (Sweden)

Full Text Available Background Causal models of physiological systems can be immensely useful in medicine as they may be used for both diagnostic and therapeutic reasoning. Aims In this paper we investigate how an agent may use the theory of belief change to rectify simple causal models of changing blood sugar levels in diabetes patients. Method We employ the semantic approach to belief change together with a popular measure of distance called Dalal distance between different state descriptions in order to implement a simple application that simulates the effectiveness of the proposed method in helping an agent rectify a simple causal model. Results Our simulation results show that distance-based belief change can help in improving the agent’s causal knowledge. However, under the current implementation there is no guarantee that the agent will learn the complete model and the agent may at times get stuck in local optima. Conclusion Distance-based belief change can help in refining simple causal models such as the example in this paper. Future work will include larger state-action spaces, better distance measures and strategies for choosing actions.

Kinzang Chhogyal

2012-09-01

113

Water level indicator for nuclear reactor  

International Nuclear Information System (INIS)

Purpose: To correctly indicate the water level in a reactor under all operating conditions by correcting the apparent decrease in the indication of a wide range water level indicator due to flow rate in the reactor core and apparent variations in the indication of the wide range water level indicator due to subcooling of the feedwater. Constitution: The water level signal of a wide range water level indicator is corrected in accordance with a flow rate correction signal and a subcooling correction signal by a water level deviation correcting adder, so the water level indicator will thus produce an actual water level signal, preferably matched with the indication of a narrow range water level indicator, to a wide range corrected water level indicator. The flow rate correction signal is obtained as an output signal of a function generator to which a reactor core flow rate signal is input and which incorporates a reactor core flow rate correction function. Further, the subcooling correction signal is obtained as an output signal of a function generator to which the temperature difference signal of a pump inlet temperature signal and a main steam temperature signal are input, and which also incorporates a subcooling correction function. (Yoshino, Y.)

114

Numerical simulation of the impacts of water level variation on water age in Dahuofang Reservoir  

Science.gov (United States)

The transport timescales were investigated in response to water level variation under different constant flow rates in Dahuofang Reservoir. The concept of water age was applied to quantify the transport timescales. A three-dimensional hydrodynamic model was developed based on the Environmental Fluid Dynamics Code (EFDC). The model was calibrated for water surface elevation and temperature profiles from April 1, 2008 to October 31, 2008. Comparisons of observed and modeled data showed that the model reproduced the water level fluctuation and thermal stratification during warm season and vertical mixing during cold season fairly well. The calibrated model was then applied to investigate the response of water age to water level changes in Dahuofang Reservoir. Model results showed that water age increases from confluence toward dam zone. In the vertical direction, the water age is relatively uniform at upstream and stratifies further downstream, with a larger value at bottom layer than at surface layer. Comparisons demonstrated that water level variation has a significant impact on transport timescales in the reservoir. The impact of water level drawdown on water age is stronger at bottom layer than at surface layer. Under high flow conditions, the water age decreases 0-20 days at surface layer and 15-25 days at bottom layer. Under mean flow conditions, the water age decreases 20-30 days at surface layer and 30-50 days at bottom layer. Furthermore, the impact is minor in the upstream and increases further downstream. The vertical stratification of water age weakens as the water level decreases. This study provides a numerical tool to quantify the transport timescale in Dahuofang Reservoir and supports adaptive management of regional water resources by local authorities.

Li, Xinwen; Shen, Yongming

2014-11-01

115

Mesoscopic Fluctuations Of Orbital Magnetic Response In Level-Quantized Metals  

OpenAIRE

We evaluate the distribution function of mesoscopic fluctuations of orbital magnetic response in finite-size level-quantized metal particles and Aharonov-Bohm rings for temperatures smaller than the mean level spacing. We find a broad distribution with the reduced moments much larger than the mean. For strong spin-orbit interaction we find very long tails due to thermal activation of large effective moments of the electrons at the Fermi level.

Serota, R. A.

2001-01-01

116

Photosynthetic responses of Lupinus albus to soil water fluctuations  

OpenAIRE

Lupinus albus plants were grown in 3 dm3 pots in a semi-controled greenhouse. Two water regimes were imposed: water deficit (S, 47% of soil capacity), and control (T, 86% of soil capacity). Plants water status was monitored through foliar relative water content (TRA) and pre-dawn (ypd) and midday water potential (ymd). Gas exchanges, chlorophyll a fluorescence and photosynthetic capacity (Amax) were measured. Pigments and soluble protein were quantified and antioxidant system enzy...

Barrote, Isabel; Oso?rio, Maria Leonor; Oso?rio, Ju?lio; David, Maria Manuela; Correia, Maria Joa?o

2002-01-01

117

NOAA: About Water Levels, Tides and Currents  

Science.gov (United States)

A comprehensive lesson on what causes tides, current and past techniques for predicting tides, how and why water level is measured, and the challenges of measuring water currents. Site provides additional links to other NOAA tide resources.

118

Terrestrial Waters and Sea Level Variations on Interannual Time Scale  

Science.gov (United States)

On decadal to multi-decadal time scales, thermal expansion of sea waters and land ice loss are the main contributors to sea level variations. However, modification of the terrestrial water cycle due to climate variability and direct anthropogenic forcing may also affect sea level. For the past decades, variations in land water storage and corresponding effects on sea level cannot be directly estimated from observations because these are almost non-existent at global continental scale. However, global hydrological models developed for atmospheric and climatic studies can be used for estimating total water storage. For the recent years (since mid-2002), terrestrial water storage change can be directly estimated from observations of the GRACE space gravimetry mission. In this study, we analyse the interannual variability of total land water storage, and investigate its contribution to mean sea level variability at interannual time scale. We consider three different periods that, each, depend on data availability: (1) GRACE era (2003-2009), (2) 1993-2003 and (3) 1955-1995. For the GRACE era (period 1), change in land water storage is estimated using different GRACE products over the 33 largest river basins worldwide. For periods 2 and 3, we use outputs from the ISBA-TRIP (Interactions between Soil, Biosphere, and Atmosphere-Total Runoff Integrating Pathways) global hydrological model. For each time span, we compare change in land water storage (expressed in sea level equivalent) to observed mean sea level, either from satellite altimetry (periods 1 and 2) or tide gauge records (period 3). For each data set and each time span, a trend has been removed as we focus on the interannual variability. We show that whatever the period considered, interannual variability of the mean sea level is essentially explained by interannual fluctuations in land water storage, with the largest contributions arising from tropical river basins.

Llovel, W.; Becker, M.; Cazenave, A.; Jevrejeva, S.; Alkama, R.; Decharme, B.; Douville, H.; Ablain, M.; Beckley, B.

2011-01-01

119

Fluctuation of Corrected Serum Calcium Levels Following Partial and Total Thyroidectomy  

OpenAIRE

Objectives: To identify any fluctuation of corrected serum calcium levels and to determine the presence of sub-clinical hypocalcaemia following partial and total thyroidectomy with preservation of at least two parathyroid glands. Design: A prospective study. Setting: Tertiary Head & Neck referral unit. Patients: Eighty five patients undergoing partial or total thyroidectomy with or without laryngectomy from April ...

Vikas Malik; Watson, Glen J.; Phua, Chu Q.; Prad Murthy

2011-01-01

120

Do fluctuations in endogenous melatonin levels predict the occurrence of postoperative cognitive dysfunction (POCD)?  

Science.gov (United States)

Delirium is a complex neuropsychiatric disorder that has an adverse impact on CNS function. Abnormal fluctuation of melatonin secretion occurs in the postoperative delirium (POD) in elderly patients. POD is strongly associated with early postoperative cognitive dysfunction (POCD). The aim of this study is to test if significant fluctuation of melatonin secretion perioperatively might indicates POCD. A total of 97 patients, ages 65-80 years, scheduled for major orthopedic surgery or abdominal surgery which was expected to last more than 2 h, were consecutively recruited into this study. Neuropsychological evaluation was performed 1 d before and one week after surgery. Morning urine samples were collected on the day of surgery and on days 1, 2 and 7 after surgery. The 6-SMT/creatinine ratio (M/C ratio) was employed to give an objective estimate of urine 6-SMT concentration. Ultimately, 95 patients completed assessments and were included in the analysis. POCD was found in 30 patients (31.6%) at 1 week after operation. There was significant fluctuation in urinary 6-SMT in 39 of the 95 patients (as evidenced by urinary 6-SMT levels increased or decreased by more than twofold compared with their preoperative baseline). Fluctuations in 6-SMT levels occurred on different days and in some patients lasted for more than 1 d. The incidence of POCD in patients with 6-SMT fluctuation was significantly higher (p < 0.01). The results indicate that in the first week after major noncardiac surgery, POCD occurs in a significant proportion of people, and is linked to fluctuations in endogenous melatonin levels. Measurement of urinary 6-SMT during the perioperative period may assist the diagnosis of POCD. PMID:24417656

Wu, Yan; Wang, Jiawan; Wu, AnShi; Yue, Yun

2014-11-01

121

Novel method to compare tropospheric path delay fluctuations with 22-GHz water vapor line emissions  

Science.gov (United States)

Tropospheric phase fluctuation due to the water vapor content is one of difficult problems which degrades imaging performances of radio interferometry. One of the potential solutions is differential radiometry observations to measure the differential water vapor content along the line of sights. We developed a 22-GHz-line radiometer to be mounted on a ground data-link antenna which supplies the timing reference signal for a space VLBI satellite, HALCA. This system will allow us to compare directly the atmospheric phase fluctuation with the water vapor content along a single line of sight measured by the radiometer.

Asaki, Yoshiharu; Kobayashi, Hideyuki; Hagiwara, Naoki; Ishiguro, Masato

2000-07-01

122

Solute Transport Under Water Table Fluctuations in a Fine Sand and a Sandy Clay Loam Soil  

Directory of Open Access Journals (Sweden)

Full Text Available Drainage contributes to removing the excess of water from cultivated land. In general, most common drainage systems lead to loss of fertilizers applied for plant growth and yield improvement. Thus, the main objective of this work was to study experimentally the redistribution of solutes within the soil profile caused by water table fluctuations by making use of a non-reactive tracer in laboratory studies on soil columns. Two soil materials, namely fine sand and a sandy clay loam soil, were used in this study. Use was made of potassium chloride as a non-reactive tracer. Profiles of chloride redistribution as a function of depth caused by a first drainage of a saturated column with chloride in the surface layer, sub-irrigation and a second drainage were obtained for the fine sand columns with draining water levels at depths 25.5 and 44.5 cm, and for the sandy clay loam columns with a draining water level at depth 44.5 cm. Although only results for water table depth at 44.5 cm for both soils materials are presented. The redistribution of chloride in both the fine sand and the sandy clay loam columns was dominantly attributed to convective movement of solutes and was considered to be little influenced by diffusion. Preferential flow could have taken place through large sized pores of the fine sand columns. The knowledge and data of this study is a contribution towards that needed to define operation strategies for sub-irrigation-drainage systems which can lead to optimize fertilizers use by crops.

Cesáreo Landeros-Sánchez

2013-12-01

123

Model of m-level low-frequency current fluctuations in metal thermionic cathodes  

Science.gov (United States)

A new model of low-frequency fluctuations, based on the thermionic current model [Mathematical Handbook for Scientists and Engineers, New York, 1961; Introduction to Statistical Radio-Physic. Part 1: Random Processes, Moscow, 1976 (in Russian)], has been designed. The proposed model provides calculation of realization, auto-correlation function (ACF) and power spectral density (PSD) of an m-level quantum signal. This model has allowed to explain the reason of very small magnitude of low-frequency (LF) boundary (10 -4 to 10 -2 Hz) on experimental spectra of LF current fluctuations in a metal thermionic cathodes.

Ghots, S. S.; Bakhtizin, R. Z.

2003-06-01

124

Water level measurement uncertainty during BWR instability  

International Nuclear Information System (INIS)

This paper addresses the performance of the water-level measurement system in a boiling water reactor (BWR) during severe instability oscillations which, under some circumstances, can occur during an anticipated transient without SCRAM (ATWS). Test data from a prototypical mock-up of the water-level measurement system was used to refine and calibrate a water-level measurement system model. The model was then used to predict level measurement system response, using as boundary conditions vessel pressures calculated by ppercase RETRAN for an ATWS/instability event.The results of the study indicate that rapid pressure changes in the reactor pressure vessel which cause oscillations in downcomer water level, coupled with differences in instrument line lengths, can produce errors in the sensed water level. Using nominal parameters for the measurement system components, a severe instability transient which produced a 0.2 m peak-to-minimum water-level oscillation in the vessel downcomer was predicted to produce pressure difference equivalent to a 0.7 m level oscillation at the input to the differential pressure transmitter, 0.5 m oscillation at the output of the transmitter, and an oscillation of 0.3 m on the water-level indicator in the control room. The level measurement system error, caused by downcomer water-level oscillations and instrument line length differential, is mitigated by damping both in the differential pressure transmitter used to infer level and in the contritter used to infer level and in the control room display instrument. ((orig.))

125

Water Table Fluctuation in Tidal Lowland for Developing Agricultural Water Management Strategies  

Directory of Open Access Journals (Sweden)

Full Text Available The research objective is to evaluate the water status in the tertiary block of tidal lowland for developing water management strategies and cropping pattern for food crop agriculture. The research was conducted in tidal lowland reclamation areas of Delta Saleh South Sumatera. The methodology used in this research was survey and monitoring. The result showed that the study area has a potential of acid sulphate soil which is indicated by phyrite layer at 60 cm below the soil surface. Variation of water table was very high in the range of 0-2 cm at rainy season and it was drop up to 90 to 100 cm below soil surface at dry season. This conditions result in the soil oxidation and the pH drop up to 2.5-3.5 (very acid. Analysis of water surplus and deficit during one year period was calculated by surplus excess water under 30 cm (SEW-30 and showed that the area study was experienced water deficit. Analysis of groundwater effect on soil moisture content showed that the critical water level was in 60 cm below soil surface. The soil moisture content at this point in the root zone was dropped into the wilting point level. It means that the water availability for crop water requirement is inadequate. For sustainable agriculture in the area study, the water table should be maintained in 50-60 cm below soil surface. Therefore, the recommendation of water management strategies in the study area is water retention in combination with control drainage system.

Momon Sodik Imanudin

2010-09-01

126

Development of Mechanical Water Level Controller  

Directory of Open Access Journals (Sweden)

Full Text Available The automatic water level controller is a device designed to regulate automatically the pumping of water to an overhead tank without allowing the water in the tank to be exhausted. The design of this mechanical device was achieved using the Archimedes principle of floatation; having a float which determines the water level in the tank depending on the choice of the minimum (lower and maximum (upper level inscribed in the tank. The fundamental attribute of this device is the ease in design, fabrication and mounting at a lower cost. Its testing had shown and proved that it works efficiently with Archimedes’ principle of floatation. This eliminates the frequent human intervention/monitoring of the water level in the overhead tank to control overflow manually, thereby eliminating water and energy wastages.

Akonyi Nasiru Sule

2012-10-01

127

Multifractal detrended fluctuation analysis in examining scaling properties of the spatial patterns of soil water storage  

OpenAIRE

Knowledge about the scaling properties of soil water storage is crucial in transferring locally measured fluctuations to larger scales and vice-versa. Studies based on remotely sensed data have shown that the variability in surface soil water has clear scaling properties (i.e., statistically self similar) over a wider range of spatial scales. However, the scaling property of soil water storage to a certain depth at a field scale is not well understood. The major challenges in scaling analysis...

Biswas, A.; Zeleke, T. B.; Si, B. C.

2012-01-01

128

KARST WATER LEVEL PREDICTION BY DATA OF THE BÜKK KARST WATER LEVEL MONITORING SYSTEM  

OpenAIRE

To define the exploitable water reserve of Bükk is important to support the sustainable water-supply of Miskolc. The prior water level prediction method was a trend line fitting method on measured data of a concrete monitoring point. The expectable character of water level change was determined by extension of trend line. End of 2011 the karst water level was decreased under absolute minimum value of 20 years database. Inspection of prior prediction method and find alternative prediction pos...

Le?na?rt, La?szlo?; Darabos, Eniko?

2012-01-01

129

Water levels in continuously monitored wells in the Yucca Mountain area, Nevada, 1985--88  

Energy Technology Data Exchange (ETDEWEB)

Water levels have been monitored hourly in 15 wells completed in 23 depth intervals in the Yucca Mountain area, Nevada. Water levels were monitored using pressure transducers and were recorded by data loggers. The pressure transducers were periodically calibrated by raising and lowering them in the wells. The water levels were normally measured at approximately the same time that the transducers were calibrated. Where the transducer output appeared reasonable, it was converted to water levels using the calibrations and manual water- level measurements. The amount of transducer output that was converted to water levels ranged from zero for several intervals to about 98 percent for one interval. Fourteen of the wells were completed in Tertiary volcanic rocks and one well was completed in Paleozoic carbonate rocks. Each well monitored from one to four depth intervals. Water-level fluctuation caused by barometric pressure changes and earth tides were observed.

Luckey, R.R.; Lobmeyer, D.H.; Burkhardt, D.J.

1993-07-01

130

Shallow Water Internal Waves and Associated Acoustic Intensity Fluctuations  

Directory of Open Access Journals (Sweden)

Full Text Available Physical oceanographic and acoustic data were simultaneously collected from the coastalwaters of the Arabian Sea. Acoustic transmissions were carried out from an anchored vesselusing 620 Hz transducer and received by an array of hydrophones moored at ~5 km away fromthe anchorage. Thermal structure in this region was characterised by a tri-layer structure, ie, astrong thermocline (> 0.4 oC/m sandwiched between an upper (< 10 m and bottom (> 25 mhomogeneous layer. High-resolution (sampled at 10 s interval temperature data from mooredsensors revealed intense internal wave activity. The maximum value of Brunt-Vaisala frequency,which is the maximum frequency limit of internal waves in the thermocline, suggests that theupper frequency limit of the internal wave, which can be generated during this period, is 23 cph(2.6 min. High and low frequency waves caused variations of ~3 oC and ~5 oC respectively inthe temperature field. But the low frequency internal waves were found to contain maximumenergy compared to the high frequency waves. Fluctuations of 8-12 dB were noticed in themeasured acoustic intensity values in the presence of low frequency internal waves. Simulationstudies carried out using parabolic equation model using 620 Hz source indicated well-definedducted propagation with minimum transmission loss, when the source was kept within thehomogeneous layer. The presence of tri-layer thermal structure, ie, a strong gradient layersandwiched between an upper and bottom homogeneous layer, caused surface and bottom channelpropagation in this region.

P.V. Hareesh Kumar

2006-10-01

131

Timing vocal behavior: lack of temporal overlap avoidance to fluctuating noise levels in singing Eurasian wrens.  

Science.gov (United States)

Many animals live in or near urban areas that have become increasingly widespread and noisy over the last century. Especially those species that rely heavily on acoustics for communication may be affected by these elevated anthropogenic noise levels. Many bird species that sing to defend their territories and to attract mates may have to exploit specific noise coping strategies to persist in such acoustically challenging conditions. Eurasian wrens (Troglodytes troglodytes), like several other bird species, have been shown in a previous experiment to time their vocalizations such that they avoid overlap with other singing birds. Here, we tested whether Eurasian wrens also time their songs to avoid overlap with fluctuating anthropogenic noise. However, we did not find any evidence in favor of this potential phenomenon. Territorial wrens persisted in singing without temporal adjustments in noisy territories with 'natural' fluctuations of traffic noise levels as well as during experimental exposure to intermittent white noise. PMID:25454773

Yang, Xiao-Jing; Slabbekoorn, Hans

2014-10-01

132

Geochemical Changes in the Caspian Salt Marshes Due to the Sea Level Fluctuations  

OpenAIRE

The Caspian Sea is subject to alternating transgressions and regressions that exert a strong impact on the topography, sediments, vegetation, and soils in coastal zones. The last transgression of the Caspian Sea (1978-1995) caused the development of a marsh-lagoon system along the accumulative seashore of the Central Dagestan. Salt marshes are complex and dynamic systems highly vulnerable to sea level fluctuations; therefore, they may be considered as a regional model of rapid environmental c...

Kasimov, Nicolay S.; Gennadiev, Alexandre N.; Kasatenkova, Maria S.; Lychagin, Michail Y.; Kroonenberg, Salomon B.; Peter Koltermann

2012-01-01

133

Spectral properties of thermal fluctuations on simple liquid surfaces below shot noise levels  

OpenAIRE

We study the spectral properties of thermal fluctuations on simple liquid surfaces, sometimes called ripplons. Analytical properties of the spectral function are investigated and are shown to be composed of regions with simple analytic behavior with respect to the frequency or the wave number. The derived expressions are compared to spectral measurements performed orders of magnitude below shot noise levels, which is achieved using a novel noise reduction method. The agreeme...

Aoki, Kenichiro; Mitsui, Takahisa

2011-01-01

134

Thermocouple-type water level monitoring device  

International Nuclear Information System (INIS)

A water level monitoring device for monitoring a water level in an upper plenum above a reactor core of a PWR type reactor container comprises an elongate cylindrical containing tube, and having a bubble separation portion disposed at the lower end thereof. A plurality of water level detector guide tubes are supported vertically by a dripping preventing plate in the containing tube. Water level detectors are inserted into the guide tubes such that each of vertical positions thereof is made different. A heat generation wire connected in a U-like shape to a lead wire and a chromel wire connected in a U-like shape by way of the alumel wire covered by an insulation material are disposed in the covering tube of the water level detector. The heat generation wire is not wound into a coil but extends in an axial direction while reciprocating at least once in the vicinity of a hot contact point. With such a constitution, responsibility is not worsened and erroneous observation of water level due to scattering of water droplets is not caused. (I.N.)

135

Experimental study on thermalhydraulics in thermal striping phenomena. Comparison of temperature fluctuations between sodium and water  

International Nuclear Information System (INIS)

A quantitative evaluation on thermal striping, in which temperature fluctuation due to convective mixing causes high cycle thermal fatigue in structural components, is of importance for structural integrity and reactor safety. Thermal conductivity of sodium is approximately 100 times larger than that of water. Thus, temperature fluctuation characteristics will be different between sodium, which is used as a coolant of a fast reactor, and water, which is used in general industries. In this study, a comparison of convective mixing among jets was performed in parallel triple wall jets with the same geometries between sodium and water. The discharged velocity in the sodium experiment was experimental parameter and set at the same velocity and the same Reynolds number in comparison with the water experiment. And, also, the velocity ratio among the triple jets was varied to change flow pattern. It was seen that the water jets were mixed in slightly closer region to the nozzle than in sodium jets. As for the power spectrum densities (PSD) of temperature fluctuation, the PSD of sodium was similar to the PSD of water under the same discharged velocity condition. At the neighborhood of the wall, the lower frequency component in the PSD of sodium decreased in comparison with the PSD of water. It was shown that the amplitude and frequency characteristics obtained by rain-flow method, which was important to evaluate structural damage by the thermal fatigue, were identical between e thermal fatigue, were identical between sodium and water overall. These experimental results show that water experiment could simulate the frequency and the amplitude in temperature fluctuation characteristics in the sodium cooled reactor. (author)

136

Pressurized water reactor level instrumentation  

International Nuclear Information System (INIS)

The need for design modifications on both BWRs and PWRs to obtain correct reactor-coolant level indication during abnormal conditions has been receiving greater emphasis since the events at TMI 2. This paper discusses some of the engineering and installation experiences for the plants where Fluor Engineers was involved as the Architect/Engineer (A/E). Described are two units using the standard Westinghouse design of three differential-pressure transmitters per train, as well as a third plant which utilized a design in which only two differential-pressure transmitters per train were used in conjunction with a microprocessor-based monitoring system. Cost savings were achieved by using a unique penetration design and by routing the instrument sense lines in unistrut, using standard cable tray support details. The reactor head attachment was also a unique and cost-effective design which had been analyzed using finite element techniques. Some valuable lessons learned with using cryofit fittings for the instrument sense lines are discussed

137

Shallow Water Internal Waves and Associated Acoustic Intensity Fluctuations  

OpenAIRE

Physical oceanographic and acoustic data were simultaneously collected from the coastal waters of the Arabian Sea. Acoustic transmissions were carried out from an anchored vessel using 620 Hz transducer and received by an array of hydrophones moored at ~5 km away from the anchorage. Thermal structure in this region was characterised by a tri-layer structure, ie, a strong thermocline (> 0.4 oC/m) sandwiched between an upper ( 25 m) homogeneous layer. High-resolution (sampl...

Hareesh Kumar, P. V.; Sanilkumar, K. V.; Panchalai, V. N.

2006-01-01

138

Small angle x-ray scattering study of fluctuations in 1-propanol-water and 2-propanol-water systems  

International Nuclear Information System (INIS)

Small-angle x-ray scattering (SAXS) measurements have been carried out on the 1-propanol (NPA)-water system and on the 2-propanol (IPA)-water system at 20 degree C. In the NPA-water system, the zero angle intensity, the concentration fluctuation, the Kirkwood-Buff parameters, and Debye's correlation lengths have been determined at various concentrations. In the IPA-water system, the zero angle intensity and Debye's correlation lengths have also been determined. In both the NPA-water and IPA-water systems, all obtained parameters have maxima at about 0.2 of the mole fraction of alcohol. In terms of these parameters, the mixing state of the NPA-water and IPA-water systems is discussed and compared with that of the TBA-water system

139

Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores  

Directory of Open Access Journals (Sweden)

Full Text Available Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was tectonically formed most likely within the Pliocene and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60 m water depth. According to our data, significant lake level fluctuations with prominent lowstands of ca. 60 and 35 m below the present water level occurred during Marine Isotope Stage (MIS 6 and MIS 5, respectively. The effect of these lowstands on biodiversity in most coastal parts of the lake is negligible, due to only small changes in lake surface area, coastline, and habitat. In contrast, biodiversity in shallower areas was more severely affected due to disconnection of today sub-lacustrine springs from the main water body. Multichannel seismic data from deeper parts of the lake clearly image several clinoform structures stacked on top of each other. These stacked clinoforms indicate significantly lower lake levels prior to MIS 6 and a stepwise rise of water level with intermittent stillstands since its existence as water-filled body, which might have caused enhanced expansion of endemic species within Lake Ohrid.

K. Lindhorst

2010-11-01

140

Spatial correlation of dipole fluctuations in liquid water  

Science.gov (United States)

The molecular dipole moments and local environments of water in its liquid phase were examined for a series of first-principles Gibbs ensemble Monte Carlo simulations along the vapour-liquid coexistence curve using the Becke-Lee-Yang-Parr (BLYP) and Perdew-Burke-Ernzerhof (PBE) exchange/correlation density functionals. Molecular dipole moments were computed using maximally localized Wannier functions with the Berry phase scheme, while the structure was analysed with respect to tetrahedral order parameter and hydrogen bonding. Increasing the temperature results in a decrease of both the average molecular dipole moment and the local structure, although the width of the dipole distribution remains fairly constant. A correlation is found between the extent of the local structure and the magnitude of the molecular dipole moment, but this correlation is limited to the first solvation shell.

McGrath, M. J.; Siepmann, J. I.; Kuo, I.-F. W.; Mundy, C. J.

141

Dynamics of phreatophyte root growth relative to a seasonally fluctuating water table in a Mediterranean-type environment.  

Science.gov (United States)

While seasonal redistribution of fine root biomass in response to fluctuations in groundwater level is often inferred in phreatophytic plants, few studies have observed the in situ growth dynamics of deep roots relative to those near the surface. We investigated the root growth dynamics of two Banksia species accessing a seasonally dynamic water table and hypothesized that root growth phenology varied with depth, i.e. root growth closest to the water table would be influenced by water table dynamics rather than surface micro-climate. Root in-growth bags were used to observe the dynamics of root growth at different soil depths and above-ground growth was also assessed to identify whole-plant growth phenology. Root growth at shallow depths was found to be in synchrony with above-ground growth phenophases, following increases in ambient temperature and soil water content. In contrast, root growth at depth was either constant or suppressed by saturation. Root growth above the water table and within the capillary fringe occurred in all seasons, corresponding with consistent water availability and aerobic conditions. However, at the water table, a seasonal cycle of root elongation with drawdown in summer followed by trimming in response to water table rise and saturation in winter, was observed. The ability to grow roots year-round at the capillary fringe and redistribute fine root biomass in response to groundwater drawdown is considered critical in allowing phreatophytes, in seasonally water-limited environments, to maintain access to groundwater throughout the year. PMID:22692384

Canham, Caroline A; Froend, Raymond H; Stock, William D; Davies, Muriel

2012-12-01

142

Advanced methods for modeling water-levels and estimating drawdowns with SeriesSEE, an Excel add-in  

Science.gov (United States)

Water-level modeling is used for multiple-well aquifer tests to reliably differentiate pumping responses from natural water-level changes in wells, or “environmental fluctuations.” Synthetic water levels are created during water-level modeling and represent the summation of multiple component fluctuations, including those caused by environmental forcing and pumping. Pumping signals are modeled by transforming step-wise pumping records into water-level changes by using superimposed Theis functions. Water-levels can be modeled robustly with this Theis-transform approach because environmental fluctuations and pumping signals are simulated simultaneously. Water-level modeling with Theis transforms has been implemented in the program SeriesSEE, which is a Microsoft® Excel add-in. Moving average, Theis, pneumatic-lag, and gamma functions transform time series of measured values into water-level model components in SeriesSEE. Earth tides and step transforms are additional computed water-level model components. Water-level models are calibrated by minimizing a sum-of-squares objective function where singular value decomposition and Tikhonov regularization stabilize results. Drawdown estimates from a water-level model are the summation of all Theis transforms minus residual differences between synthetic and measured water levels. The accuracy of drawdown estimates is limited primarily by noise in the data sets, not the Theis-transform approach. Drawdowns much smaller than environmental fluctuations have been detected across major fault structures, at distances of more than 1 mile from the pumping well, and with limited pre-pumping and recovery data at sites across the United States. In addition to water-level modeling, utilities exist in SeriesSEE for viewing, cleaning, manipulating, and analyzing time-series data.

Halford, Keith; Garcia, C. Amanda; Fenelon, Joe; Mirus, Benjamin B.

2012-01-01

143

The effect of interaural-level-difference fluctuations on the externalization of sound  

DEFF Research Database (Denmark)

Real-world sound sources are usually perceived as externalized and thus properly localized in both direction and distance. This is largely due to (1) the acoustic filtering by the head, torso, and pinna, resulting in modifications of the signal spectrum and thereby a frequency-dependent shaping of interaural cues and (2) interaural cues provided by the reverberation inside an enclosed space. This study first investigated the effect of room reverberation on the spectro-temporal behavior of interaural level differences (ILDs) by analyzing dummy-head recordings of speech played at different distances in a standard listening room. Next, the effect of ILD fluctuations on the degree of externalization was investigated in a psychoacoustic experiment performed in the same listening room. Individual binaural impulse responses were used to simulate a distant sound source delivered via headphones. The ILDs were altered using a gammatone filterbank for analysis and resynthesis, where the envelopes of the left and right-ear signals were modified such that the naturally occurring fluctuations of the ILDs were restricted. This manipulation reduced the perceived degree of externalization. This was consistent with the analysis of short-term ILDs at different distances showing that a decreased distance to the sound source also reduced the ILD fluctuations. © 2013 Acoustical Society of America.

Catic, Jasmina; Santurette, Sébastien

2013-01-01

144

Fluctuations in Species-Level Protein Expression Occur during Element and Nutrient Cycling in the Subsurface  

Energy Technology Data Exchange (ETDEWEB)

While microbial activities in environmental systems play a key role in the utilization and cycling of essential elements and compounds, microbial activity and growth frequently fluctuates in response to environmental stimuli and perturbations. To investigate these fluctuations within a saturated aquifer system, we monitored a carbon-stimulated in situ Geobacter population while iron reduction was occurring, using 16S rRNA abundances and high-resolution tandem mass spectrometry proteome measurements. Following carbon amendment, 16S rRNA analysis of temporally separated samples revealed the rapid enrichment of Geobacter-like environmental strains with strong similarity to G. bemidjiensis. Tandem mass spectrometry proteomics measurements suggest high carbon flux through Geobacter respiratory pathways, and the synthesis of anapleurotic four carbon compounds from acetyl-CoA via pyruvate ferredoxin oxidoreductase activity. Across a 40-day period where Fe(III) reduction was occurring, fluctuations in protein expression reflected changes in anabolic versus catabolic reactions, with increased levels of biosynthesis occurring soon after acetate arrival in the aquifer. In addition, localized shifts in nutrient limitation were inferred based on expression of nitrogenase enzymes and phosphate uptake proteins. These temporal data offer the first example of differing microbial protein expression associated with changing geochemical conditions in a subsurface environment.

Wilkins, Michael J.; Wrighton, Kelly C.; Nicora, Carrie D.; Williams, Kenneth H.; McCue, Lee Ann; Handley, Kim M.; Miller, C. S.; Giloteaux, L.; Montgomery, A. P.; Lovley, Derek R.; Banfield, Jillian F.; Long, Philip E.; Lipton, Mary S.

2013-03-05

145

Analysis of Environmental Data and Landscape Characterization on Multiple WetlandTypes Using Water Level Loggers and GIS Techniques in Tampa, FL  

Science.gov (United States)

To better characterize the relationships between both adjacent hydrology/ precipitation and nutrient processing with groundwater level fluctuations, continuous water level data are being collected across three dominant wetland types, each with varied landscape characteristics. Th...

146

Water Level Detection Using Synthetic Aperture Radar Imagery  

International Nuclear Information System (INIS)

Reservoir water levels are of interest for international safeguards and domestic monitoring because they can be used as indicators of processing activity, uranium mine tailings protection status, or power generation for clandestine operation. Monitoring of water levels using satellite technology, especially civilian synthetic aperture radar (SAR) for remote or restricted-access sites worldwide has the potential to be a valuable tool for national/international safeguards as well as environmental monitoring applications. Unlike optical sensors, SAR is capable of reliable repeat monitoring regardless of cloud cover or solar illumination, i.e. it can image the target through clouds and darkness. Because of this ability, quick turn around for a SAR image is almost always guaranteed. SAR is very sensitive to the land/water interface and can be used to extract detailed elevation models. SAR is also sensitive to metallic structures or objects and can thus be useful in detection of heavy equipment or undeclared construction at decommissioned facilities. Although spaceborne SAR cannot match the resolution of optical satellites, future SAR satellites will offer much better resolution (e.g., approximately 3 metres for RADARSAT-2). Furthermore, future SAR satellites will offer different polarization and frequency channels to provide terrain and vegetation classification. The objective is to investigate the use of SAR for water level detection using Canada's RADARSAT-1 imagery. Thrion using Canada's RADARSAT-1 imagery. Three Canadian sites were chosen for our study: Niagara Area Hydro Reservoir; Quirke Lake uranium tailings management facility (TMF); and JEB Pit TMF. Initial results, using RADARSAT-1 data acquired over a three year period, show dramatic changes in both the total water surface area and markers (natural or man-made) becoming visible as the water level decreases. These very promising results indicated that SAR imagery can be used as an excellent tool for mapping remote location (which is useful for inspection planning), object detection (verification of declared activities, or detection of undeclared activities), and detection of water level fluctuation (which may be linked to a clandestine power generation during a period where optical sensors are not effective, e.g. at night or during adverse weather conditions). Additional analysis of RADARSAT-1 data, supportable by ground truth information and IKONOS imagery, is being carried out and further results are expected to be available soon. Large steep walled or terraced reservoirs, as in the case of JEB Pit TMF would require a different analysis technique. Scoping work indicated that it would be possible to deduce the water level by measuring the wall height using 'radar shadow', in a manner similar to the exploitation of shadows in optical images

147

Analysis of the cross-correlation between seismicity and water level in the Aswan area (Egypt) from 1982 to 2010  

OpenAIRE

In this study the correlation between the monthly fluctuations of the water level of the Aswan High Dam and monthly number of earthquakes from 1982 to 2010, which occurred in the surrounding area, was investigated. Our findings reveal that significant correlation is present during the period 1982–1993 between water level and shallow seismicity (depth less than 15 km). The deep seismicity (depth larger than 15 km) is significantly correlated with the water level between January and April 198...

Telesca, L.; Elshafey Fat Elbary, R.; El-ela Amin Mohamed, A.; Elgabry, M.

2012-01-01

148

Characterization of the temperature fluctuations generated in a thermal mixing tee (sodium versus water behavior)  

International Nuclear Information System (INIS)

The temperature fluctuations occurring in 1800 inlet-let angle pipe tee thermal mixers with and without inlet reducer pipes are characterized in both amplitude and frequency. Sodium and water data from different sized tees have allowed delineation of the size and fluid medium modeling laws required for the extrapolation of reduced-scale water model temperature fluctuation data to prototype LMFBR sodium mixers. The phenomena of flow corner cutoff and thermal buoyancy at a tee juncture have also been studied and their effects on mixer performance delineated. The information presented is vital both to the design of thermal-fatigue-free mixers and to the understanding of thermal mixing in complex flows; much of it has not been peviously available

149

Effects of a long term water level reduction on the ecology and water quality in an eastern Mediterranean lake  

Directory of Open Access Journals (Sweden)

Full Text Available Water level fluctuations play a significant role in the lake nutrient dynamics, and consequently may have a strong influence on the biological communities and productivity. In this article we investigated the effects of a long term water level reduction on key chemistry parameters and major biological communities in an eastern Mediterranean lake. Our approach is based on temporal data regarding water quality, fish, zooplankton and aquatic vegetation that are representative of different water level periods. The results revealed significant correlations between water level, conductivity and chloride concentration suggesting a clear effect of the water level reduction on the water quality. Among the key findings of this study is the significant increase of zoobenthivorous fish (roach and carp from 1973 to 1999 that correlates with the water level reduction. A decline of charophytes is also noted whereas the reed beds appear to have expanded at the shallower parts of the lake. The zooplankton composition of the lake is mostly dominated by nauplii, rotifer and small-sized crustaceans indicating a possible effect of fish predation. Overall, this article has ascertained an alarming shift of water quality and composition of biological communities that can be attributed to the combined effects of eutrophication and the extreme water level decrease.

Stefanidis K.

2013-09-01

150

Drought impact on water use efficiency and intra-annual density fluctuations in Erica arborea on Elba (Italy).  

Science.gov (United States)

Erica arborea (L) is a widespread Mediterranean species, able to cope with water stress and colonize semiarid environments. The eco-physiological plasticity of this species was evaluated by studying plants growing at two sites with different soil moistures on the island of Elba (Italy), through dendrochronological, wood-anatomical analyses and stable isotopes measurements. Intra-annual density fluctuations (IADFs) were abundant in tree rings, and were identified as the key parameter to understand site-specific plant responses to water stress. Our findings showed that the formation of IADFs is mainly related to the high temperature, precipitation patterns and probably to soil water availability, which differs at the selected study sites. The recorded increase in the (13) C-derived intrinsic water use efficiency at the IADFs level was linked to reduced water loss rather than to increasing C assimilation. The variation in vessel size and the different absolute values of ?(18) O among trees growing at the two study sites underlined possible differences in stomatal control of water loss and possible differences in sources of water uptake. This approach not only helped monitor seasonal environmental differences through tree-ring width, but also added valuable information on E.?arborea responses to drought and their ecological implications for Mediterranean vegetation dynamics. PMID:23848555

Battipaglia, Giovanna; DE Micco, Veronica; Brand, Willi A; Saurer, Matthias; Aronne, Giovanna; Linke, Petra; Cherubini, Paolo

2014-02-01

151

NOS Tides and Water Levels Discovery Kit  

Science.gov (United States)

National Ocean Service (NOS) scientists collect, study, predict and disseminate information about tides and water levels. Tutorial introduces the causes and variations of tides and currents, their impacts on human activities, navigation and organisms. Lesson plans include data for classroom activities, as well as resource links and teacher guides. A NSTA SciLinks selected site.

152

Beach water table fluctuations due to spring-neap tides: moving boundary effects  

Science.gov (United States)

Tidal water table fluctuations in a coastal aquifer are driven by tides on a moving boundary that varies with the beach slope. One-dimensional models based on the Boussinesq equation are often used to analyse tidal signals in coastal aquifers. The moving boundary condition hinders analytical solutions to even the linearised Boussinesq equation. This paper presents a new perturbation approach to the problem that maintains the simplicity of the linearised one-dimensional Boussinesq model. Our method involves transforming the Boussinesq equation to an ADE (advection-diffusion equation) with an oscillating velocity. The perturbation method is applied to the propagation of spring-neap tides (a bichromatic tidal system with the fundamental frequencies ? 1 and ? 2) in the aquifer. The results demonstrate analytically, for the first time, that the moving boundary induces interactions between the two primary tidal oscillations, generating a slowly damped water table fluctuation of frequency ?1- ?2, i.e., the spring-neap tidal water table fluctuation. The analytical predictions are found to be consistent with recently published field observations.

Li, L.; Barry, D. A.; Stagnitti, F.; Parlange, J.-Y.; Jeng, D.-S.

153

Hydro static water level systems at Fermilab  

Energy Technology Data Exchange (ETDEWEB)

Several Hydrostatic Water Leveling systems (HLS) are in use at Fermilab. Three systems are used to monitor quadrupoles in the Tevatron and two systems are used to monitor ground motion for potential sites for the International Linear Collider (ILC). All systems use capacitive sensors to determine the water level of water in a pool. These pools are connected with tubing so that relative vertical shifts between sensors can be determined. There are low beta quadrupoles at the B0 and D0 interaction regions of Tevatron accelerator. These quadrupoles use BINP designed and built sensors and have a resolution of 1 micron. All regular lattice superconducting quadrupoles (a total of 204) in the Tevatron use a Fermilab designed system and have a resolution of 6 microns. Data on quadrupole motion due to quenches, changes in temperature will be presented. In addition data for ground motion for ILC studies caused by natural and cultural factors will be presented.

Volk, J.T.; Guerra, J.A.; Hansen, S.U.; Kiper, T.E.; Jostlein, H.; Shiltsev, V.; Chupyra, A.; Kondaurov, M.; Singatulin, S.

2006-09-01

154

Spatial distribution of groundwater recharge in SOUTH KOREA applying GIS and multivariate statistics to water-table fluctuation  

Science.gov (United States)

This study is objected to determine areal estimates and spatial variations of groundwater recharges in entire inland of South Korea. Relationships between groundwater recharge ratio and various hydrogeological factors were quantified, and the contributions of each factor were evaluated. For this purpose, firstly, a modified water-table fluctuation method was developed to calculate the recharge ratio using cumulative precipitation and its corresponding water-table fluctuation data. Cross-correlation analyses were conducted for rainfall and groundwater level time series, resulting in the mean time of recharge after precipitation events to be shorter than two days. The method was applied to the monitoring data of three monitoring stations, and showed in consistency with the results from applying different methods to the same sites. Application of this method could be limited by the reliability of specific yield measurement. Water-table fluctuation curves from the 66 National Groundwater Monitoring Stations were used for the multiple regression analysis. Analysis of hydrogeological independent variables at each monitoring station was conducted with two data sets: 1) all stations as a group, 2) stations in each river basin. Mean of three-year annual recharge ratio, calculated through water-table fluctuation method, was a dependent variable. For the first case, the effective precipitation and the thickness of vadose zone, identified as significant factors to the recharge ratios, could explain the recharges of 24.9 % of the total monitoring stations. Secondly, in the basin scale, regression models could explain recharges of 54.3 % of monitoring stations in Han, 97.6 % in Keum, 87.1 % in Nakdong, and 86.9 % in Youngsan and Seomjin river basins. An RMS error of less than 10 % was produced in every basin. The spatial distribution of recharges was evaluated using a map overlay technique of GIS according to the quantified contributions of independent variables. Consequently, the average recharge ratio of each river basin was estimated to be 9.3 %, 7.7 %, 14.8 % and 2.5 % for Han, Nakdong, Keum and Youngsan and Seomjin river basins, respectively. Groundwater recharge ratios estimated based on the regression model in the basin scale was close to the average values for each river basin, except for Youngsan and Seomjin river basin where the modified water-table method could produce better estimates. GIS techniques could present the effects on the groundwater recharge of complicated hydrogeological factors varied in space.

Moon, S.; Woo, N.; Lee, K.

2003-04-01

155

Multifractal detrended fluctuation analysis in examining scaling properties of the spatial patterns of soil water storage  

Directory of Open Access Journals (Sweden)

Full Text Available Knowledge about the scaling properties of soil water storage is crucial in transferring locally measured fluctuations to larger scales and vice-versa. Studies based on remotely sensed data have shown that the variability in surface soil water has clear scaling properties (i.e., statistically self similar over a wider range of spatial scales. However, the scaling property of soil water storage to a certain depth at a field scale is not well understood. The major challenges in scaling analysis for soil water are the presence of localized trends and nonstationarities in the spatial series. The objective of this study was to characterize scaling properties of soil water storage variability through multifractal detrended fluctuation analysis (MFDFA. A field experiment was conducted in a sub-humid climate at Alvena, Saskatchewan, Canada. A north-south transect of 624-m long was established on a rolling landscape. Soil water storage was monitored weekly between 2002 and 2005 at 104 locations along the transect. The spatial scaling property of the surface 0 to 40 cm depth was characterized using the MFDFA technique for six of the soil water content series (all gravimetrically determined representing soil water storage after snowmelt, rainfall, and evapotranspiration. For the studied transect, scaling properties of soil water storage are different between drier periods and wet periods. It also appears that local controls such as site topography and texture (that dominantly control the pattern during wet states results in multiscaling property. The nonlocal controls such as evapotranspiration results in the reduction of the degree of multiscaling and improvement in the simple scaling. Therefore, the scaling property of soil water storage is a function of both soil moisture status and the spatial extent considered.

A. Biswas

2012-03-01

156

Investment choice and perceived mating intentions regulated by external resource cues and internal fluctuation in blood glucose levels  

Science.gov (United States)

We examined resource allocation priorities in the framework of an updated Maslow hierarchy of fundamental human needs. In Experiment 1, the participants in the food abundance priming condition viewing photos of high-calorie food allocated more money to savings than to spending. However, the participants preferred spending to savings under the condition of mating availability priming with romantic photographs. In Experiment 2, before and after drinking either water or a sugary beverage, fasting participants rated photos of a conversation between a man and a woman. Water drinking lowered the rating scores of mating intentions as well as blood glucose (BG) levels. The sugary drink buffered this decline in sexual perceptivity. Overall, the change in BG levels was positively associated with changes in the ratings of mating intentions but was not associated with other likelihood ratings. These results suggest that both external cues of food and mating resources and internal BG fluctuation regulate the cognitive priority of physiological needs vs. mate acquisition and retention. PMID:25610412

Rao, Li-Lin; Wang, Xiao-Tian; Li, Shu

2015-01-01

157

Investment choice and perceived mating intentions regulated by external resource cues and internal fluctuation in blood glucose levels.  

Science.gov (United States)

We examined resource allocation priorities in the framework of an updated Maslow hierarchy of fundamental human needs. In Experiment 1, the participants in the food abundance priming condition viewing photos of high-calorie food allocated more money to savings than to spending. However, the participants preferred spending to savings under the condition of mating availability priming with romantic photographs. In Experiment 2, before and after drinking either water or a sugary beverage, fasting participants rated photos of a conversation between a man and a woman. Water drinking lowered the rating scores of mating intentions as well as blood glucose (BG) levels. The sugary drink buffered this decline in sexual perceptivity. Overall, the change in BG levels was positively associated with changes in the ratings of mating intentions but was not associated with other likelihood ratings. These results suggest that both external cues of food and mating resources and internal BG fluctuation regulate the cognitive priority of physiological needs vs. mate acquisition and retention. PMID:25610412

Rao, Li-Lin; Wang, Xiao-Tian; Li, Shu

2014-01-01

158

Application of remote sensing techniques to understand the mechanisms behind the Caspian Sea lake-level fluctuations  

Science.gov (United States)

The Caspian Sea has exhibited significantly wide range of water-level fluctuations in its history. The primary factor for these oscillations has been overwhelmingly ascribed to climate-induced variations; geologic-related processes have been suggested to be trivial and negligible. This work processed TopexPoseidon data to estimate Lake-level heights for the Caspian Sea from the beginning of 1993 to August 2005. In order to improve the accuracy, the new Gravity Recovery and Climate Experiment orbits data, new Sea State Bias model, and Topex Microwave Radiometer drift correction were applied to the default altimetry data. The Caspian Sea hydrologic budget from 1998 to 2005 was also calculated using remote sensing and ground-based data. The National Center for Environmental Prediction Department of Energy Reanalysis 2 meteorological data provided all the variables necessary for the Penman method to estimate evaporation over the Caspian Sea. The Tropical Rainfall Measuring Mission rainfall data was utilized to estimate precipitation onto the Caspian Sea. This study reveals that lake-level changes from 1998 to 2005 are essentially controlled by meteorological factors based on the fact that a relatively minor difference between the water budget residuals and CSLL changes in the Caspian Sea. Moreover, the trend observed in the Caspian Sea lake level over the last several decades is closely correlated with Lake Van and Lake Urmia. However, the relatively higher dissimilarity present in 2000 and 2001 could imply that the Caspian Sea needs to lose some of its water to attain water balance. The two significant earthquakes with normal fault focal mechanisms and magnitudes of 6.8 and 6.5 Mw could be responsible for the Caspian Sea lake-level decline in 2000 and 2001. The contribution of submarine mud volcano eruptions to increase Caspian Sea lake level is likely to be negligible on the basis of submarine mud volcanic eruptions in 2003. Both the crustal deformation based on the GPS measurements in the Caspian Sea region and the amount of oil and natural gas production offshore the Caspian Sea are not causing considerable changes in the Caspian Sea lake level.

Ozyavas, Aziz

159

Investigation of Temperature Fluctuations Caused by Steam-Water Two-Phase Flow in Pressurizer Spray Piping  

Science.gov (United States)

In a PWR plant, a steam-water two-phase flow may possibly exist in the pressurizer spray pipe under a normal operating condition since the flow rate of the spray water is not sufficient to fill the horizontal section of the pipe completely. Initiation of high cycle fatigue cracks is suspected to occur under such thermally stratified two phase flow conditions due to cyclic thermal stress fluctuations caused by oscillations of the water surface. Such oscillations cannot be detected by the measurement of temperature on outer surface of the pipe. In order to clarify the flow and thermal conditions in the pressurizer spray pipe and assess their impact on the pipe structure, an experiment was conducted for a steam-water flow at a low flow rate using a mock-up pressurizer spray pipe. The maximum temperature fluctuation of about 0.2 times of the steam-water temperature difference was observed at the inner wall around water surface in the test section. Visualization tests were conducted to investigate the temperature fluctuation phenomena. It was shown that the fluid temperature fluctuations were not caused by the waves on the water surface, but were caused by liquid temperature fluctuations in water layer below the interface. The influence of small amount of non-condensable gas dissolved in the reactor coolant on the liquid temperature fluctuation phenomena was investigated by injecting air into the experimental loop. The air injection attenuated the liquid temperature fluctuations in the water layer since the condensation was suppressed by the non- condensable gas. It is not expected that wall temperature fluctuation in the actual PWR plant may exceed the temperature equivalent to the fatigue limit stress amplitude when it is assumed to be proportional to the steam-water temperature difference.

Miyoshi, Koji; Nakamura, Akira; Takenaka, Nobuyuki; Oumaya, Toru

160

Kinetic parameters and intraindividual fluctuations of ochratoxin A plasma levels in humans  

International Nuclear Information System (INIS)

The mycotoxin ochratoxin A (OTA) is a rodent carcinogen produced by species of the ubiquitous fungal genera Aspergillus and Penicillium. OTA is found in a variety of food items and as a consequence is also found in human plasma (average concentrations found in this study: 0.1-1 ng OTA/ml plasma). To improve the scientific basis for cancer risk assessment the toxicokinetic profile of OTA was studied in one human volunteer following ingestion of 395 ng 3H-labeled OTA (3.8 ?Ci). A two-compartment open model consisting of a central compartment was found to best describe the in vivo data. This two-compartment model consisted of a fast elimination and distribution phase (T1/2 about 20 h) followed by a slow elimination phase (renal clearance about 0.11 ml/min.) and a calculated plasma half-life of 35.55 days. This half-life was approximately eight times longer than that determined previously in rats. In addition, the intraindividual fluctuation of OTA plasma levels was investigated in eight individuals over a period of 2 months. The concentrations determined ranged between 0.2 and 0.9 ng OTA/ml plasma. The plasma levels in some individuals remained nearly constant over time, while others varied considerably (e.g. increase of 0.4 ng/ml within 3 days, decrease of 0.3 ng/ml within 5 days) during the observation period. This intraindividual fluctuation in OTA plasma levels, which may represent differences in OTA exposure and/or metabolism, as well as the losure and/or metabolism, as well as the large difference in plasma half-life in humans compared to rats must be taken into consideration when the results of rat cancer study data are extrapolated to humans for risk assessment purposes. (orig.)

161

Kinetic parameters and intraindividual fluctuations of ochratoxin A plasma levels in humans  

Energy Technology Data Exchange (ETDEWEB)

The mycotoxin ochratoxin A (OTA) is a rodent carcinogen produced by species of the ubiquitous fungal genera Aspergillus and Penicillium. OTA is found in a variety of food items and as a consequence is also found in human plasma (average concentrations found in this study: 0.1-1 ng OTA/ml plasma). To improve the scientific basis for cancer risk assessment the toxicokinetic profile of OTA was studied in one human volunteer following ingestion of 395 ng {sup 3}H-labeled OTA (3.8 {mu}Ci). A two-compartment open model consisting of a central compartment was found to best describe the in vivo data. This two-compartment model consisted of a fast elimination and distribution phase (T{sub 1/2} about 20 h) followed by a slow elimination phase (renal clearance about 0.11 ml/min.) and a calculated plasma half-life of 35.55 days. This half-life was approximately eight times longer than that determined previously in rats. In addition, the intraindividual fluctuation of OTA plasma levels was investigated in eight individuals over a period of 2 months. The concentrations determined ranged between 0.2 and 0.9 ng OTA/ml plasma. The plasma levels in some individuals remained nearly constant over time, while others varied considerably (e.g. increase of 0.4 ng/ml within 3 days, decrease of 0.3 ng/ml within 5 days) during the observation period. This intraindividual fluctuation in OTA plasma levels, which may represent differences in OTA exposure and/or metabolism, as well as the large difference in plasma half-life in humans compared to rats must be taken into consideration when the results of rat cancer study data are extrapolated to humans for risk assessment purposes. (orig.)

Studer-Rohr, I. [Inst. of Toxicology, Swiss Federal Inst. of Tech. and Univ. of Zurich, Schwerzenbach (Switzerland); Dept. of Food Science, Swiss Federal Inst. of Tech., Zurich (Switzerland); Schlatter, J. [Toxicology Section, Div. of Food Science, Swiss Federal Office of Public Health, Zurich (Switzerland); Dietrich, D.R. [Dept. of Environmental Toxicology, Univ. of Konstanz, Konstanz (Germany); Inst. of Toxicology, Swiss Federal Inst. of Tech. and Univ. of Zurich, Schwerzenbach (Switzerland)

2000-11-01

162

Quantum fluctuations and isotope effects in ab initio descriptions of water  

International Nuclear Information System (INIS)

Isotope substitution is extensively used to investigate the microscopic behavior of hydrogen bonded systems such as liquid water. The changes in structure and stability of these systems upon isotope substitution arise entirely from the quantum mechanical nature of the nuclei. Here, we provide a fully ab initio determination of the isotope exchange free energy and fractionation ratio of hydrogen and deuterium in water treating exactly nuclear quantum effects and explicitly modeling the quantum nature of the electrons. This allows us to assess how quantum effects in water manifest as isotope effects, and unravel how the interplay between electronic exchange and correlation and nuclear quantum fluctuations determine the structure of the hydrogen bond in water

163

Magnitude and sign correlations in conductance fluctuations of horizontal oil water two-phase flow  

International Nuclear Information System (INIS)

In experiment we firstly define five typical horizontal oil-water flow patterns. Then we introduce an approach for analyzing signals by decomposing the original signals increment into magnitude and sign series and exploring their scaling properties. We characterize the nonlinear and linear properties of horizontal oil-water two-phase flow, which relate to magnitude and sign series respectively. We find that the joint distribution of different scaling exponents can effectively identify flow patterns, and the detrended fluctuation analysis (DFA) on magnitude and sign series can represent typical horizontal oil-water two-phase flow dynamics characteristics. The results indicate that the magnitude and sign decomposition method can be a helpful tool for characterizing complex dynamics of horizontal oil-water two-phase flow.

164

Numerical analysis of a three-phase system with a fluctuating water table  

International Nuclear Information System (INIS)

Numerical simulations are presented of a one-dimensional, multiphase flow system that involves the redistribution of aqueous-phase liquids and nonaqueous-phase liquids (NAPLs) by a fluctuating water table. The numerical analyses were completed using an integrated-volume, finite-difference-based solution scheme of the governing multiphase conservation equations and constitutive theory. Conservation equations were solved for two components water and oil, with the assumption of a passive gas-phase. Nonlinearities introduced into the governing conservation equations through the constitutive theory were handled with a multivariable Newton-Raphson iterative scheme. The functional relationships between the phase relative permeability, the phase saturation, and phase pressures in porous media were described with a general theoretical model that includes the effects of air and oil occlusion during imbibition. Parameters required for the theoretical model were defined for two-phase systems (e.g., air- water, air-oil, and oil-water). The theoretical model assumes that wettability decreases in the following order: water, oil, air. Results from the numerical simulations are compared against measurements taken from a previous multiphase flow experiment. The experiment involved subjecting an initially water-drained, three-phase system (i.e., air-oil-water), to a fluctuating water table. The experimental objective was to quantify the entrapment of air and NAPL by phases of greater wettability under dynamic conditions. Comparison of numerical and experimental results were made for two ratios of imbibition to drainage characteristic, curve-shape parameters and two models for relative permeability in two-phase systems. A description of the numerical methods used to solve the governing conservation and constitutive equations for multiphase hysteretic conditions is given

165

Numerical analysis of a three-phase system with a fluctuating water table  

Energy Technology Data Exchange (ETDEWEB)

Numerical simulations are presented of a one-dimensional, multiphase flow system that involves the redistribution of aqueous-phase liquids and nonaqueous-phase liquids (NAPLs) by a fluctuating water table. The numerical analyses were completed using an integrated-volume, finite-difference-based solution scheme of the governing multiphase conservation equations and constitutive theory. Conservation equations were solved for two components water and oil, with the assumption of a passive gas-phase. Nonlinearities introduced into the governing conservation equations through the constitutive theory were handled with a multivariable Newton-Raphson iterative scheme. The functional relationships between the phase relative permeability, the phase saturation, and phase pressures in porous media were described with a general theoretical model that includes the effects of air and oil occlusion during imbibition. Parameters required for the theoretical model were defined for two-phase systems (e.g., air- water, air-oil, and oil-water). The theoretical model assumes that wettability decreases in the following order: water, oil, air. Results from the numerical simulations are compared against measurements taken from a previous multiphase flow experiment. The experiment involved subjecting an initially water-drained, three-phase system (i.e., air-oil-water), to a fluctuating water table. The experimental objective was to quantify the entrapment of air and NAPL by phases of greater wettability under dynamic conditions. Comparison of numerical and experimental results were made for two ratios of imbibition to drainage characteristic, curve-shape parameters and two models for relative permeability in two-phase systems. A description of the numerical methods used to solve the governing conservation and constitutive equations for multiphase hysteretic conditions is given.

White, M.D.; Lenhard, R.J.

1993-03-01

166

Relative sea-level fluctuations since deglaciation in western North America  

Science.gov (United States)

We synthesize the state of knowledge regarding post-glacial sea-level changes on the Pacific coast of North America based on more than 2,000 radiocarbon dates from Oregon to Alaska. Relative sea-level (RSL) history over the late Quaternary is complex owing to regional differences in crustal deformation (neotectonics), changes in global ocean volumes (eustasy) and the depression and rebound of the Earth's crust in response to ice sheets on land (isostasy). The RSL history is further complicated by the diachronous timing of the Last Glacial Maximum (LGM) and subsequent ice retreat across the region. For instance, the LGM ranged in timing from as early as 25 ka (14C years) BP in south-central Alaska, to between 15-14 ka BP at its southernmost extent in southwest BC and northern Washington. During this time, the Cordilleran Ice Sheet depressed the crust over which it formed and, as the ice thinned and retreated, the sea rapidly transgressed isostatically depressed lowland areas. Early-postglacial RSL highstands within the region range from ~25 masl in Cook Inlet, Alaska, to approximately 200 masl at fjord head locations such as Kitimat and in the Lower Mainland of southern BC. As the crust rebounded, RSL dropped. In contrast to the BC mainland, sea levels at the LGM were 150 m lower than present in Haida Gwaii on BC's north coast, due to an isostatic forebulge raising the land. Forebulge collapse led to a rise in relative sea level, up to about 15-18 masl by 9.5 ka BP. Spatial and temporal gaps exist in our understanding of post-glacial sea-level change and landscape evolution along the Pacific coast as data constraining RSL fluctuations around the LGM are limited (e.g. south-central Alaska). Similarly, we lack understanding of post-glacial sea-level fluctuations on BC's central coast. We present an overview of the differences in RSL patterns from Oregon to south-central Alaska and discuss the geophysical foundations for them, as well as present new data filling data gaps on the central BC coast.

Shugar, D. H.; Walker, I. J.; Lian, O. B.; Eamer, J.; Neudorf, C. M.

2013-12-01

167

Optimal control of a qubit coupled to a two-level fluctuator  

CERN Document Server

A central challenge for implementing quantum computing in the solid state is decoupling the qubits from the intrinsic noise of the material. We investigate limits of controllability for a paradigmatic model: A single qubit coupled to a two-level fluctuator exposed to a heat bath. We systematically search for optimal pulses using a generalization of the novel open system Gradient Ascent Pulse Engineering (GRAPE) algorithm. We show and explain that next to the known optimal bias point of this model, there are optimal shapes which refocus unwanted terms in the Hamiltonian. We study the limitations of control set by the decoherence properties in the fast flipping regime, which go beyond a simple random telegraph noise model. This can lead to a significant improvement of quantum operations in hostile environments.

Rebentrost, P; Serban, I; Wilhelm, F K

2006-01-01

168

Composite fermions in the half-filled Landau level: why gauge field fluctuations are important.  

Science.gov (United States)

We discuss the effect of infrared fluctuations of the Chern-Simons gauge field on the single-particle Green's function of composite fermions in the half-filled Landau level. We show that in the limit of vanishing frequency ? the leading radiative correction to the fermion - gauge field vertex gives rise to a self-energy correction which exceeds the self-energy without vertex correction by a factor of ln ( ?0 / ? ), where ?0 is some finite frequency. We argue that the logarithmic correction indicates that summation of vertex corrections to all orders will lead to a well-defined quasi-particle peak in the spectral function, in agreement with the result of higher-dimensional bosonization on a curved Fermi surface( P. Kopietz and G. E. Castilla, Phys. Rev. Lett. 78), 314 (1997)..

Kopietz, Peter

1998-03-01

169

The roles of shear and cross-correlations on the fluctuation levels in simple stochastic models. Revision  

International Nuclear Information System (INIS)

Highly simplified models of random flows interacting with background microturbulence are analyzed. In the limit of very rapid velocity fluctuations, it is shown rigorously that the fluctuation level of a passively advected scalar is not controlled by the rms shear. In a model with random velocities dependent only on time, the level of cross-correlations between the flows and the background turbulence regulates the saturation level. This effect is illustrated by considering a simple stochastic-oscillator model, both exactly and with analysis and numerical solutions of the direct-interaction approximation. Implications for the understanding of self-consistent turbulence are discussed briefly

170

Pleistocene sea-level fluctuations and human evolution on the southern coastal plain of South Africa  

Science.gov (United States)

Humans evolved in Africa, but where and how remain unclear. Here it is proposed that the southern coastal plain (SCP) of South Africa may have served as a geographical point of origin through periodic expansion and contraction (isolation) in response to glacial/interglacial changes in sea level and climate. During Pleistocene interglacial highstands when sea level was above -75 m human populations were isolated for periods of 360-3400 25-yr generations on the SCP by the rugged mountains of the Cape Fold Belt, climate and vegetation barriers. The SCP expands five-fold as sea level falls from -75 to -120 m during glacial maxima to form a continuous, unobstructed coastal plain accessible to the interior. An expanded and wet glacial SCP may have served as a refuge to humans and large migratory herds and resulted in the mixing of previously isolated groups. The expansive glacial SCP habitat abruptly contracts, by as much as one-third in 300 yr, during the rapid rise in sea level associated with glacial terminations. Rapid flooding may have increased population density and competition on the SCP to select for humans who expanded their diet to include marine resources or hunted large animals. Successful adaptations developed on an isolated SCP are predicted to widely disperse during glacial terminations when the SCP rapidly contracts or during the initial opening of the SCP in the transition to glacial maxima. The hypothesis that periodic expansion and contraction of the SCP, as well as the coastal plain of North Africa, contributed to the stepwise origin of our species over the last 800 thousand years (kyr) is evaluated by comparing the archeological, DNA and sea-level records. These records generally support the hypothesis, but more complete and well dated records are required to resolve the extent to which sea-level fluctuations influenced the complex history of human evolution.

Compton, John S.

2011-03-01

171

Anandamide levels fluctuate in the bovine oviduct during the oestrous cycle.  

Science.gov (United States)

Mammalian oviduct acts as a reservoir for spermatozoa and provides an environment in which they may compete for the opportunity to fertilize the oocyte. Whilst in the oviduct spermatozoa undergo capacitation essential for fertilization. Sperm-oviduct interaction is essential for sperm capacitation and is a tightly regulated process influenced by the local microenvironment. Previously we reported that the endocannabinoid anandamide (AEA) regulates sperm release from epithelial oviductal cells by promoting sperm capacitation. The aims of this work were to measure the AEA content and to characterize the main AEA metabolic pathway in the bovine oviduct and determine how these change through the oestrous cycle. In this study, the levels of AEA and two other N-acylethanolamines, N-oleoylethanolamine and N-palmitoylethanolamine, were measured in bovine oviduct collected during different stages of oestrous cycle by ultra high performance liquid chromatography tandem mass spectrometry. Results indicated that intracellular oviductal epithelial levels of all three N-acylethanolamines fluctuate during oestrous cycle. Anandamide from oviductal fluid also varied during oestrous cycle, with the highest values detected during the periovulatory period. Endocannabinoid levels from ipsilateral oviduct to ovulation were higher than those detected in the contralateral one, suggesting that levels of oviductal AEA may be regulated by ovarian hormones. The expression and localization of N-acylethanolamines metabolizing enzymes in bovine oviduct were also determined by RT-PCR, Western blot, and immunohistochemistry but no change was found during the oestrous cycle. Furthermore, nanomolar levels of AEA were detected in follicular fluids, suggesting that during ovulation the mature follicle may contribute to oviductal AEA levels to create an endocannabinoid gradient conducive to the regulation of sperm function for successful fertilization. PMID:23977311

Gervasi, Maria Gracia; Marczylo, Timothy H; Lam, Patricia M; Rana, Shashi; Franchi, Ana M; Konje, Justin C; Perez-Martinez, Silvina

2013-01-01

172

Detecting drawdowns masked by environmental stresses with water-level models  

Science.gov (United States)

Detecting and quantifying small drawdown at observation wells distant from the pumping well greatly expands the characterized aquifer volume. However, this detection is often obscured by water level fluctuations such as barometric and tidal effects. A reliable analytical approach for distinguishing drawdown from nonpumping water-level fluctuations is presented and tested here. Drawdown is distinguished by analytically simulating all pumping and nonpumping water-level stresses simultaneously during the period of record. Pumping signals are generated with Theis models, where the pumping schedule is translated into water-level change with the Theis solution. This approach closely matched drawdowns simulated with a complex three-dimensional, hypothetical model and reasonably estimated drawdowns from an aquifer test conducted in a complex hydrogeologic system. Pumping-induced changes generated with a numerical model and analytical Theis model agreed (RMS as low as 0.007 m) in cases where pumping signals traveled more than 1 km across confining units and fault structures. Maximum drawdowns of about 0.05 m were analytically estimated from field investigations where environmental fluctuations approached 0.2?m during the analysis period.

Garcia, C.A.; Halford, K.J.; Fenelon, J.M.

2013-01-01

173

Late Holocene lake-level fluctuations in Walker Lake, Nevada, USA  

Science.gov (United States)

Walker Lake, a hydrologically closed, saline, and alkaline lake, is situated along the western margin of the Great Basin in Nevada of the western United States. Analyses of the magnetic susceptibility (??), total inorganic carbon (TIC), and oxygen isotopic composition (??18O) of carbonate sediments including ostracode shells (Limnocythere ceriotuberosa) from Walker Lake allow us to extend the sediment record of lake-level fluctuations back to 2700??years B.P. There are approximately five major stages over the course of the late Holocene hydrologic evolution in Walker Lake: an early lowstand (> 2400??years B.P.), a lake-filling period (??? 2400 to ??? 1000??years B.P.), a lake-level lowering period during the Medieval Warm Period (MWP) (??? 1000 to ??? 600??years B.P.), a relatively wet period (??? 600 to ??? 100??years B.P.), and the anthropogenically induced lake-level lowering period (< 100??years B.P.). The most pronounced lowstand of Walker Lake occurred at ??? 2400??years B.P., as indicated by the relatively high values of ??18O. This is generally in agreement with the previous lower resolution paleoclimate results from Walker Lake, but contrasts with the sediment records from adjacent Pyramid Lake and Siesta Lake. The pronounced lowstand suggests that the Walker River that fills Walker Lake may have partially diverted into the Carson Sink through the Adrian paleochannel between 2700 to 1400??years B.P. ?? 2006 Elsevier B.V. All rights reserved.

Yuan, F.; Linsley, B.K.; Howe, S.S.; Lund, S.P.; McGeehin, J.P.

2006-01-01

174

Hydrostatic Water Level Systems At Homestake DUSEL  

Science.gov (United States)

Two arrays of Fermilab-style hydrostatic water level sensors have been installed in the former Homestake gold mine in Lead, SD, the site of the new Deep Underground Science and Engineering Laboratory (DUSEL). Sensors were constructed at Fermilab from 8.5 cm diameter PVC pipe (housing) that was sealed on the ends and fit with a proximity sensor. The instrument have a height of 10 cm. Two ports in each sensor housing provide for connectivity, the upper port for air and the bottom port for water. Multiple instruments connected in series provide a precise water level and differences in readings between successive sensors provide for ground tilt to be resolved. Sensor resolution is 5 ?m per count and has a range of approximately 1.25 cm. Data output from each sensor is relayed to a Fermilab-constructed readout card that also has temperature/relative humidity and barometric pressure sensors connected. All data are relayed out of the mine by fiber optic cable and can be recorded by Ethernet at remote locations. The current arrays have been installed on the 2000-ft level (610 m) and consist of six instruments in each array. Three sensors were placed in a N-S oriented drift and three in an E-W oriented drift. Using this orientation, it is anticipated that tilt direction may be resolved in addition to overall tilt magnitude. To date the data show passage of earth tides and frequency analysis has revealed five components to this signal, three associated with the semi-diurnal (~12.4 hr) and two with the diurnal (~24.9 hr) tides. Currently, installation methods are being analyzed between concrete pillar and rib-mounting using the existing setup on the 2000-ft level. Using these results, two additional arrays of Fermilab instruments will be installed on the 4550-ft and 4850-ft levels (1387 and 1478 m, respectively). In addition to Fermilab instruments, several high resolution Budker tiltmeters (1 ?m resolution) will be installed in the mine workings in the near future, some correlated to Fermilab instruments (for comparative analysis) and others in independent arrays. All tiltmeter data will be analyzed with water reduction data (currently being collected from the #6 winze as the mine is dewatered) and data from rock stress/fracture experiments to document net ground settling due to dewatering, potential collapse of stope areas and renewed excavation activities.

Stetler, L. D.; Volk, J. T.

2009-12-01

175

Critical fluctuations of the micellar triethylene glycol monoheptyl ether-water system  

Science.gov (United States)

Using the equal volume criterion and also the pseudospinodal conception the critical demixing point of the triethylene glycol monoheptyl ether/water system (C7E3/H2O) has been determined as Ycrit=0.1 and Tcrit=296.46K (Y, mass fraction of surfactant). From density measurements the critical micelle concentration (cmc) followed as Ycmc=0.007 at 288.15K and Ycmc=0.0066 at 298.15K. The (static) shear viscosity ?s and the mutual diffusion coefficient D of the C7E3/H2O mixture of critical composition have been evaluated to yield their singular and background parts. From a combined treatment of both quantities the relaxation rate ? of order parameter fluctuations has been derived. ? follows power law with universal critical exponent and amplitude ?0=3.1×109s-1. Broadband ultrasonic spectra of C7E3/H2O mixtures exhibit a noncritical relaxation, reflecting the monomer exchange between micelles and the suspending phase, and a critical term due to concentration fluctuations. The former is subject to a relaxation time distribution that broadens when approaching the critical temperature. The latter can be well represented with the aid of the dynamic scaling model by Bhattacharjee and Ferrell (BF) [Phys. Rev. A. 31, 1788 (1985)]. The half-attenuation frequency in the scaling function of the latter model is noticeably smaller (?1/2BF?1) than the theoretically predicted value ?1/2BF=2.1. This result has been taken as an indication of a coupling between the fluctuations in the local concentration and the kinetics of micelle formation, in correspondence with the idea of a fluctuation controlled monomer exchange [T. Telgmann and U. Kaatze, Langmuir 18, 3068 (2002)].

Haller, J.; Behrends, R.; Kaatze, U.

2006-03-01

176

Relationship between fluctuations in glucose levels measured by continuous glucose monitoring and vascular endothelial dysfunction in type 2 diabetes mellitus  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Fluctuations in blood glucose level cause endothelial dysfunction and play a critical role in onset and/or progression of atherosclerosis. We hypothesized that fluctuation in blood glucose levels correlate with vascular endothelial dysfunction and that this relationship can be assessed using common bedside medical devices. Methods Fluctuations in blood glucose levels were measured over 24?hours by continuous glucose monitoring (CGM on admission day 2 in 57 patients with type 2 diabetes mellitus. The reactive hyperemia index (RHI, an index of vascular endothelial function, was measured using peripheral arterial tonometry (EndoPAT on admission day 3. Results The natural logarithmic-scaled RHI (L_RHI correlated with SD (r=?0.504; PPP=0.001 and percentage of time ?200?mg/dl (r=?0.292; P=0.028. In 12 patients with hypoglycemia, L_RHI also correlated with the percentage of time at hypoglycemia (r=?0.589; P=0.044. L_RHI did not correlate with HbA1c or fasting plasma glucose levels. Furthermore, L_RHI did not correlate with LDL cholesterol, HDL cholesterol, and triglyceride levels or with systolic and diastolic blood pressures. Finally, multivariate analysis identified MAGE as the only significant determinant of L_RHI. Conclusions Fluctuations in blood glucose levels play a significant role in vascular endothelial dysfunction in type 2 diabetes. Trial registration UMIN000007581

Torimoto Keiichi

2013-01-01

177

Hydrologic conditions and lake-level fluctuations at Long Lost Lake, 1939-2004, White Earth Indian Reservation, Clearwater County, Minnesota  

Science.gov (United States)

Long Lost Lake, a closed-basin lake in Clearwater County, Minnesota, has had a substantial rise in lake level since 1990. The increased level and surface area of the lake has led to the inundation of nearby homes and roads. The U.S. Geological Survey, in cooperation with the White Earth Band of Chippewa Indians, conducted a study to document the historical lake-level fluctuations, to investigate reasons for hydrologic change, and to develop a general understanding of the hydrology of lakes that have had rapid changes in lake level. Lake levels were recorded continuously from August 2003 through December 2004. The purpose was to establish a temporal, detailed record of lake levels and to connect this record to precipitation and ground-water-level data. A long-term record is critical to understanding the relation between surface water and ground water. This is especially true for closed-basin lakes. Between August 2003 and December 2004, the lake level generally declined. The highest lake altitude was 492.58 meters above NAVD 88 on August 5, 2003, and the low of 492.11 meters above NAVD 88 occurred on August 29, 2004. Results of water-level measurements in 5 observation wells and 14 wetlands and ponds show that the water-table level is substantially higher on the north side of the lake than the lake level, providing the head pressure necessary for ground-water discharge into Long Lost Lake. In contrast, on the south and east sides of the lake, water-table levels are similar to the lake level. This indicates a general north-northwest to south-southeast ground-water flow direction. Results of a synoptic survey of lake temperature and other measurements supported the direction of water inflow and outflow. Aerial photography and a geographic information system were used to construct a historical lake record from 1939 to 2001. Lake-level increases match similar increases in precipitation, indicating a strong link between the two. Results show that lake-level increases in Long Lost Lake appear to primarily be due to natural rather than anthropogenic effects.

Christensen, Victoria G.; Bergman, Andrea L.

2005-01-01

178

Interaction of adsorbates with electric-field fluctuations near surfaces: Nonradiative lifetimes and energy-level shifts  

Science.gov (United States)

In the vacuum above surfaces, there are zero-point fluctuations in the electromagnetic field generated by zero-point charge fluctuations in the substrate. A molecule near the surface will couple to such fluctuations, with the consequence that excited states may decay via nonradiative transitions in which energy is transferred to the electronic excitations of the substrate (surface plasmons, particle hole pairs). In addition, coupling to the fluctuations will produce energy-level shifts not included in the standard version of density-functional theory. We develop a formalism that allows one to calculate the nonradiative lifetimes from this interaction, and also the energy-level shifts. We treat the electric-field fluctuations within the framework of a phenomenological theory that relates their amplitude and frequency spectrum to the optical dielectric constants of the materials from which the substrate complex is fabricated. We demonstrate that when the formalism is applied to a structureless, highly localized electron, the energy-level shift is just that given by the image potential of classical dielectric theory. In real systems one must include the effect of virtual transitions to excited states in the analysis of the level shifts. We present a quantitative study of the nonradiative lifetime of the lowest unoccupied molecular orbital (LUMO)+1 state of the magnesium porphine molecule, adsorbed on the oxide covered NiAl(110) surface, along with calculations of the energy-level shifts induced by the field fluctuations for this system. Our calculated nonradiative lifetime is in good accord with experimental data.

Mills, D. L.; Cao, J. X.; Wu, Ruqian

2007-05-01

179

Monitoring system for reactor water level  

International Nuclear Information System (INIS)

Purpose: To enable accurate judgement for reactor water level by measuring flow rate, temperature, pressure and the like of coolants flowing in and out of a BWR type reactor. Constitution: Flow rate, temperature and pressure are measured for all of the coolants flowing in and out of a reactor. The flowing-out coolants are measured in both vapor phase and liquid phase. These data are inputted into a computer, in which they are calibrated in comparison with the indication of a level detector during normal operation, or coolant amount in the reactor and the energy in the reactor are calculated upon abnormal stage, and displayed on a Braun tube. (J.P.N.)

180

Effects of Water-Pressure Fluctuations on Glacial Erosion: a Quarrying Experiment Beneath Engabreen, Norway  

Science.gov (United States)

Bedrock erosion by glaciers can play a dominant role in the evolution of high-latitude landscapes. The process that is least understood but probably responsible for most of this erosion is quarrying: the extension of preexisting cracks in subglacial bedrock and dislodgement of resultant rock fragments. On mountain slopes failure of rock masses is commonly triggered by hydraulic transients caused by rainfall or snowmelt. In contrast, the large hydraulic transients that occur beneath glaciers are usually neglected in models of large-scale glacial erosion. Rather in these models erosion rates are assumed to be a simple function of sliding velocity or ice discharge. To study quarrying in real time, a granite step (0.12 m high) was installed under 213 m of ice at the bed of Engabreen, a temperate glacier in Norway. The step protruded upward into sliding ice and was inclined up-glacier. A crack, 2 mm wide and 31 mm deep, was cut across the step, normal to its stoss surface. Acoustic-emission sensors, tested in laboratory rock-fracture experiments, monitored the growth of the crack. Water was pumped under high pressure to the bed to simulate water-pressure fluctuations like those that occur in hydraulically active areas of glacier beds. These pump tests caused a cavity between the ice and bed to open and close down-glacier from the step. Normal stress on the step and the frequency of acoustic emissions increased markedly during closures of the cavity that followed decreases in water pressure. Acoustic emissions emanated from the base of the crack. Over a three-day period the locus of emission sources extended obliquely about 90 mm toward the base of the lee surface of the step, presumably reflecting crack extension. Post-experimental inspection of the step showed that it had indeed been quarried along the trajectory indicated by acoustic emissions. These data indicate that crack growth can occur rapidly as a result of stress differences in the bed caused by decreasing water pressure in zones of ice-bed separation. Fluctuating water pressure may commonly be necessary to exceed stress thresholds required for crack growth. Thus, long-term erosion rates may not be well characterized by models that neglect these fluctuations.

Iverson, N. R.; Cohen, D.; Hooyer, T. S.; Thomason, J. F.; Jackson, M.

2005-12-01

181

Dramatic enhancement of capillary wave fluctuations of a decorated water surface  

International Nuclear Information System (INIS)

We have demonstrated by x-ray diffuse scattering that a bimolecular layer of a preformed three-tailed amphiphile, ferric stearate, drastically enhances capillary wave fluctuations on water surface due to a reduction in surface tension to 1 mN/m. The bimolecular layer is composed of molecules in symmetric configuration, on top of molecules in asymmetric configuration with ferric ions in contact with water. Unlike the usual Langmuir monolayers, this layer of molecules does not rupture under compression, but becomes thicker. This behavior mimics folding of a membrane on a liquid surface and is closely related to the cohesive interaction brought by the ferric ions. The low effective tension of this artificial membrane depends on the available area and reduces as the microscopic excess area increases

182

?????????????????????? Necessity and Methods for Reservoir Seasonal Drought Control Water Level  

Directory of Open Access Journals (Sweden)

Full Text Available ???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? Similar to the reservoir flood control water level, the drought control water level, though a new concept, is very important for reservoir drought relief operation. The definition and the importance of the drought control water level has been introduced and discussed. Some theoretical methods on the drought control water level, including the necessity of the seasonal control and how to determinate the seasonal values, have been pointed out. The reservoir drought control water level can be a guide for the further improving the management of drought, which also plays an important role in water supply engineering programming and water resources optimal allocation.

??

2012-06-01

183

Analysis of water-level data in the Yucca Mountain area, Nevada, 1985--95  

International Nuclear Information System (INIS)

From 1985 through 1995, a water-level network that consists of 28 wells for monitoring 36 depth intervals has been maintained in the Yucca Mountain area. The network includes wells that were measured manually, approximately monthly, and/or measured hourly with a transducer/data logger system. Manual water-level measurements were made with either calibrated steel tapes or single or multiconductor-cable units. All wells monitor water levels in Tertiary volcanic rocks, except one that monitors water levels in Paleozoic carbonate rocks. Annual mean water-level altitudes for all wells for the period 1985-95 ranged from 727.93 to 1,034.60 meters. The maximum range in water-level change between monthly measurements and/or monthly mean values was 12.22 meters in well USW H-3 lower interval, and the minimum range was 0.31 meter in wells UE-25 b-1 upper interval, and J-11. In 31 of the 36 depth intervals monitored, the range of water-level change was less than 1 meter. The range of standard deviation of all depth interval measurements for all wells that were monitored was 0.053 to 3.098 meters. No seasonal water-level trends were detected in any of the wells, and regional ground-water withdrawals did not appear to cause water-level changes. Most annual water-level fluctuations can be attributed to barometric and Earth-tide changes. Regional earthquakes, which occurred on June 28--29, 1992, might have simultaneously affected the water level in seven wells. Periods of rising and vel in seven wells. Periods of rising and declining water levels were observed in most wells. However, 11 years of record were not sufficient to determine if these periods were cyclic. Because a goal of monitoring water levels at Yucca Mountain is to determine if there are water-level trends that could affect the potential repository, observed water-level changes over the period of this report may not be representative of the overall long-term trends in water levels

184

Phanerozoic environmental changes in the Caucasus and adjacent areas: stratigraphy, fossil diversity, mass extinctions, sea-level fluctuations, and tectonics  

OpenAIRE

No abstract available © University of Pretoria 2008 Please cite as follows: Ruban, DA 2008, Phanerozoic environmental changes in the Caucasus and adjacent areas: stratigraphy, fossil diversity, mass extinctions, sea-level fluctuations, and tectonics, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd D628/ag

Ruban, Dmitry Aleksandrovitch

2009-01-01

185

Water Table Fluctuation in Tidal Lowland for Developing Agricultural Water Management Strategies  

OpenAIRE

The research objective is to evaluate the water status in the tertiary block of tidal lowland for developing water management strategies and cropping pattern for food crop agriculture. The research was conducted in tidal lowland reclamation areas of Delta Saleh South Sumatera. The methodology used in this research was survey and monitoring. The result showed that the study area has a potential of acid sulphate soil which is indicated by phyrite layer at 60 cm below the soil surface. Variation...

Momon Sodik Imanudin; Edi Armanto; Robiyanto Hendro Susanto; Siti Masreah Bernas

2010-01-01

186

Conductivity fluctuations in butyric acid/water and isobutyric acid/water mixtures  

Science.gov (United States)

We have measured the power spectrum SV( f) of noise voltage at current clamp of mixtures of (a) butyric acid/water, isobutyric acid/water, and KCl/water as functions of composition at constant temperature and (b) isobutyric acid/water of critical composition as function of temperature near the critical point in a frequency range of 0.1? f?3.2 kHz. At temperatures away from the critical, all spectra can be described by power law SV( f)?f -x with x?1. The amplitude of SV( f) is proportional to the applied voltage V0. Approaching the critical temperature of the system isobutyric acid/water, the spectra can be characterized by the same power law but with an exponent x?2. The amplitude of SV( f) is proportional to V20. A qualitative explanation of the properties of SV( f) of the system isobutyric acid/water of critical composition near Tc is given by taking into account that this system is reactive and that—according to Procaccia et al.—near the critical point the relaxation time ?r is expected to increase according to a power law ?r?t-? with t=(T-Tc)/Tc ?=1.25. This interpretation is in agreement with the experimental results of this study and that of Goldburg et al.

Kolb, H.-A.; Woermann, D.

1984-04-01

187

Thermal fluctuation levels of magnetic and electric fields in unmagnetized plasma: The rigorous relativistic kinetic theory  

Energy Technology Data Exchange (ETDEWEB)

Any fully ionized collisionless plasma with finite random particle velocities contains electric and magnetic field fluctuations. The fluctuations can be of three different types: weakly damped, weakly propagating, or aperiodic. The kinetics of these fluctuations in general unmagnetized plasmas, governed by the competition of spontaneous emission, absorption, and stimulated emission processes, is investigated, extending the well-known results for weakly damped fluctuations. The generalized Kirchhoff radiation law for both collective and noncollective fluctuations is derived, which in stationary plasmas provides the equilibrium energy densities of electromagnetic fluctuations by the ratio of the respective spontaneous emission coefficient and the true absorption coefficient. As an illustrative example, the equilibrium energy densities of aperiodic transverse collective electric and magnetic fluctuations in an isotropic thermal electron-proton plasmas of density n{sub e} are calculated as |?B|=?((?B){sup 2})=2.8(n{sub e}m{sub e}c{sup 2}){sup 1/2}g{sup 1/2}?{sub e}{sup 7/4} and |?E|=?((?E){sup 2})=3.2(n{sub e}m{sub e}c{sup 2}){sup 1/2}g{sup 1/3}?{sub e}{sup 2}, where g and ?{sub e} denote the plasma parameter and the thermal electron velocity in units of the speed of light, respectively. For densities and temperatures of the reionized early intergalactic medium, |?B|=6·10{sup ?18}G and |?E|=2·10{sup ?16}G result.

Yoon, P. H., E-mail: yoonp@umd.edu, E-mail: rsch@tp4.rub.de, E-mail: uk@tp4.rub.de [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Schlickeiser, R., E-mail: yoonp@umd.edu, E-mail: rsch@tp4.rub.de, E-mail: uk@tp4.rub.de [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Research Department Plasmas with Complex Interactions, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Kolberg, U., E-mail: yoonp@umd.edu, E-mail: rsch@tp4.rub.de, E-mail: uk@tp4.rub.de [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

2014-03-15

188

Thermal fluctuation levels of magnetic and electric fields in unmagnetized plasma: The rigorous relativistic kinetic theory  

International Nuclear Information System (INIS)

Any fully ionized collisionless plasma with finite random particle velocities contains electric and magnetic field fluctuations. The fluctuations can be of three different types: weakly damped, weakly propagating, or aperiodic. The kinetics of these fluctuations in general unmagnetized plasmas, governed by the competition of spontaneous emission, absorption, and stimulated emission processes, is investigated, extending the well-known results for weakly damped fluctuations. The generalized Kirchhoff radiation law for both collective and noncollective fluctuations is derived, which in stationary plasmas provides the equilibrium energy densities of electromagnetic fluctuations by the ratio of the respective spontaneous emission coefficient and the true absorption coefficient. As an illustrative example, the equilibrium energy densities of aperiodic transverse collective electric and magnetic fluctuations in an isotropic thermal electron-proton plasmas of density ne are calculated as |?B|=?((?B)2)=2.8(nemec2)1/2g1/2?e7/4 and |?E|=?((?E)2)=3.2(nemec2)1/2g1/3?e2, where g and ?e denote the plasma parameter and the thermal electron velocity in units of the speed of light, respectively. For densities and temperatures of the reionized early intergalactic medium, |?B|=6·10?18G and |?E|=2·10?16G result

189

Effect of Different Soil Water Levels on Production and Abscission of Reproductive Organs of Soybean under High Temperature  

OpenAIRE

An experiment was conducted during summer 1999 in and out sides of a glasshouse to evaluate the effect of different soil water levels on growth, physiological aspects and, production and abscission of flowers and pods of soybean. Three stress treatments were imposed by 40, 60 and 80% reduced water from flower initiation to maturity in the glasshouse. Two well-watered unstressed controls were also included for comparison of performances in and out sides of the glasshouse. Fluctuation in air te...

Begum Samsun Nahar; Takeshi Ikeda

2001-01-01

190

Thermal fatigue crack initiation and arrest behavior in labyrinth structure subjected to temperature fluctuation in pure water  

International Nuclear Information System (INIS)

At a tee junction point of piping system or labyrinth structure of pump seal, hot and cold water are mixed with each other in whirl. The vibrating mixing boundary between the hot and cold water induces a temperature fluctuation on a inside surface of the pipe just after the connection point or labyrinth land and bottom surface. The temperature fluctuation causes thermal fatigue. In this study the thermal stress distributions in the labyrinth structure were analyzed using FEM for various frequencies under the temperature fluctuation of turbulent water flow. The fracture mechanics analysis indicated that the thermal fatigue crack with relatively high frequency of 0.1 Hz to 25 Hz were arrested at a depth nearly proportional to square root of reciprocal of the frequency and it was about 3.8 mm for 1 Hz. (author)

191

Impact of scaled-down on dissolved oxygen fluctuations at different levels of the lipase synthesis pathway of Yarrowia lipolytica  

Directory of Open Access Journals (Sweden)

Full Text Available The impact of the fluctuations in dissolved oxygen tension (DOT on the lipase production by Yarrowia lipolytica has been investigated in a scale-down reactor (SDR. This bioreactor comprises a 20 l agitated vessel with an automatic valve controlling the opening and closure of the air flow line. This kind of scale-down apparatus is used in order to generate DOT gradients encountered in large-scale, while maintaining the other environmental conditions constant. The impact of DOT fluctuations has been estimated at three levels of the lipase synthesis machinery: lipase gene expression, lipase translation, lipase excretion to the extracellular medium. Among these levels, the performance of lipase production under oscillating DOT was significantly affected at the lipase gene expression level.

Delvigne, F.

2010-01-01

192

Quaternary depositional patterns and sea-level fluctuations, northeastern North Carolina  

Science.gov (United States)

A detailed record of late Quaternary sea-level oscillations is preserved within the upper 45 m of deposits along an eight km transect across Croatan Sound, a drowned tributary of the Roanoke/Albemarle drainage system, northeastern North Carolina. Drill-hole and seismic data reveal nine relatively complete sequences filling an antecedent valley comprised of discontinuous middle and early Pleistocene deposits. On interfluves, lithologically similar marine deposits of different sequences occur stacked in vertical succession and separated by ravinement surfaces. Within the paleo-drainage, marine deposits are separated by fluvial and/or estuarine sediments deposited during periods of lowered sea level. Foraminiferal and molluscan fossil assemblages indicate that marine facies were deposited in a shallow-marine embayment with open connection to shelf waters. Each sequence modifies or truncates portions of the preceding sequence or sequences. Sequence boundaries are the product of a combination of fluvial, estuarine, and marine erosional processes. Stratigraphic and age analyses constrain the ages of sequences to late Marine Isotope Stage (MIS) 6 and younger (˜ 140 ka to present), indicating multiple sea-level oscillations during this interval. Elevations of highstand deposits associated with late MIS 5 and MIS 3 imply that sea level was either similar to present during those times, or that the region may have been influenced by glacio-isostatic uplift and subsidence.

Parham, Peter R.; Riggs, Stanley R.; Culver, Stephen J.; Mallinson, David J.; Wehmiller, John F.

2007-01-01

193

Fluctuating micro-heterogeneity in water–tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies  

International Nuclear Information System (INIS)

Water–tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with xTBA ? 0.03–0.07. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at xTBA ? 0.05. We note that “islands” of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak nonlinearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, xTBA ? 0.45, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level

194

Fluctuating micro-heterogeneity in water–tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies  

Energy Technology Data Exchange (ETDEWEB)

Water–tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with x{sub TBA} ? 0.03–0.07. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at x{sub TBA} ? 0.05. We note that “islands” of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak nonlinearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, x{sub TBA} ? 0.45, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level.

Banerjee, Saikat; Furtado, Jonathan; Bagchi, Biman, E-mail: bbagchi@sscu.iisc.ernet.in [SSCU, Indian Institute of Science, Bangalore 560012 (India)

2014-05-21

195

Modelling wetland bird response to water level changes in the Lake Ontario - St. Lawrence River hydrosystem.  

Science.gov (United States)

Lake Ontario and St. Lawrence River (LOSL) wetland bird abundance and diversity are greatly influenced by lake and river hydrology. Our study used an interdisciplinary ecosystem approach, blending avian and plant ecology, ecohydraulic, statistical ecology and modelling to evaluate potential impacts of water level fluctuations on indicator species representative of the wetland breeding bird assemblages in the entire LOSL freshwater system. Multi-year (2000-2003) bird surveys captured bird distribution and density in wetland habitats under varying degrees of water inandation, depth and fluctuation. Analyses revealed strong associations between estimated breeding pair densities and plant communities, water depth, and degree of water level fluctuation during the breeding season for a suite of wetland bird species using marsh, wet meadow, shrub swamp and treed swamp habitats. These quantitative associations were used to develop wetland bird performance indicators for use in a LOSL water regulation review study. Several bird species also nest at or near the water surface and are thus vulnerable to nest flooding or stranding. Changes to the seasonal hydrology of Lake Ontario and St. Lawrence River that result in an increased frequency or magnitude of these nest failure events may have a significant impact on regional population sustainability. Long term nest record databases were analyzed to create nesting flooding and stranding probability equations based on water level increases and decreases during the breeding season. These species-specific nesting relationships were incorporated into a reproduction index. Many breeding bird species were strongly associated with specific wetland plant communities. Predicted habitat suitability, as measured by estimated breeding pair density, can also change significantly within a specific wetland plant community based solely on changes in water depth during the breeding season. Three indicator species, Black Tern, Least Bittern and Virginia Rail were selected as key environmental performance indicators for alternate regulation plan comparisons. Water regulation criteria should be such that the long term diversity and abundance of wetland plant communities and frequency of spring flooding in marsh habitats during breeding are not reduced. Magnitude and frequency of water level change during the nesting season (May-July) can also adversely impact reproductive success of many wetland bird species. As such, regulation criteria that increase the seasonal magnitude and frequency of water level change may be detrimental to the long term viability of certain regional breeding bird populations. PMID:16518674

Desgranges, Jean-Luc; Ingram, Joel; Drolet, Bruno; Morin, Jean; Savage, Caroline; Borcard, Daniel

2006-02-01

196

Seasonal fluctuations in water repellency and infiltration in a sandy loam soil after a forest fire in Galicia (NW Spain  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this work was to analyze, after a wildfire of moderate severity, the temporal fluctuations in water repellency and infiltration in a sandy loam soil under a mixed plantation of pine and eucalyptus and the comparison with an adjacent area not affected by the fire. In the burnt area and in a neighboring area not affected by the fire were collected during one year (1, 4, 6, 8 and 12 months after the fire 10 soil samples along a transect of 18 m at four depths: 0-2, 2-5, 5-10 and 10-20 cm. Soil water repellency was determined using the water drop penetration time test (WDPT test and the infiltration was measured with a mini-disc infiltrometer (pressure head h0 = -2 cm.The results show a temporal pattern of soil water repellency in the burnt and unburnt areas. Significant correlations between water repellency and soil moisture were observed, with higher correlation coefficients in the unburned area and in the surface soil layer.Soil water infiltration was significantly lower than would be expected by the coarse texture of the soil in both burnt and unburnt areas. Temporal fluctuations in unburnt soil infiltration seem to be clearly related to the transient nature of the soil water repellency, with no infiltration in samples extremely repellent. In the burned area, the soil infiltration showed much more variability and temporal fluctuations appear to be less dependent on the persistence of water repellency and more dependent on environmental conditions.The unburnt area show significant and negative correlations of soil water repellency with hydraulic conductivity and sorptivity and positive of these two parameters with soil moisture. These relationships were not observed in the burnt area. The temporal fluctuations of soil water repellency have an evident impact on soil infiltration and seem to be more influent than the effects of fire.

M. Rodríguez-Alleres

2013-05-01

197

Hydraulic interactions between fractures and bedding planes in a carbonate aquifer studied by means of experimentally induced water-table fluctuations (Coaraze experimental site, southeastern France)  

OpenAIRE

In aquifers with variable permeability, the water exchanges between high and low permeability regions are controlled by the hydraulic head gradient. Past studies have addressed this problem mainly considering steadystate hydraulic conditions. To study such exchanges during water-table fluctuations, a spring was equipped with a water-gate that creates 10-meter artificial fluctuations of the water table. The water exchanges are discussed with respect to hydrochemical and pressure measurements i...

Charmoille, A.; Binet, Ste?phane; Bertrand, C.; Guglielmi, Y.; Mudry, J.

2009-01-01

198

Historical impact of water infrastructure on water levels of the Mekong River and the Tonle Sap system  

Science.gov (United States)

The rapid rate of water infrastructure development in the Mekong Basin is a cause for concern due to its potential impact on fisheries and downstream natural ecosystems. In this paper, we analyze the historical water levels of the Mekong River and Tonle Sap system by comparing pre- and post-1991 daily observations from six stations along the Mekong mainstream from Chiang Saen (northern Thailand), to Stung Treng (Cambodia), and the Prek Kdam station on the Tonle Sap River. Observed alterations in water level patterns along the Mekong are linked to temporal and spatial trends in water infrastructure development from 1960 to 2010. We argue that variations in historical climatic factors are important, but they are not the main cause of observed changes in key hydrological indicators related to ecosystem productivity. Our analysis shows that the development of mainstream dams in the upper Mekong Basin in the post-1991 period may have resulted in a modest increase of 30-day minimum levels (+17%), but significant increases in fall rates (+42%) and the number of water level fluctuations (+75%) observed in Chiang Saen. This effect diminishes downstream until it becomes negligible at Mukdahan (northeast Thailand), which represents a drainage area of over 50% of the total Mekong Basin. Further downstream at Pakse (southern Laos), alterations to the number of fluctuations and rise rate became strongly significant after 1991. The observed alterations slowly decrease downstream, but modified rise rates, fall rates, and dry season water levels were still quantifiable and significant as far as Prek Kdam. This paper provides the first set of evidence of hydrological alterations in the Mekong beyond the Chinese dam cascade in the upper Mekong. Given the evident alterations at Pakse and downstream, post-1991 changes could also be directly attributed to water infrastructure development in the Chi and Mun basins of Thailand. A reduction of 23 and 11% in the water raising and falling rates respectively at Prek Kdam provides evidence of a diminished Tonle Sap flood pulse in the post-1991 period. Given the observed water level alterations from 1991 to 2010 as a result of water infrastructure development, we can extrapolate that future development in the mainstream and the key transboundary Srepok, Sesan, and Sekong sub-basins will have an even greater effect on the Tonle Sap flood regime, the lower Mekong floodplain, and the delta.

Cochrane, T. A.; Arias, M. E.; Piman, T.

2014-11-01

199

Systems-level modeling the effects of arsenic exposure with sequential pulsed and fluctuating patterns for tilapia and freshwater clam  

International Nuclear Information System (INIS)

The purpose of this paper was to use quantitative systems-level approach employing biotic ligand model based threshold damage model to examine physiological responses of tilapia and freshwater clam to sequential pulsed and fluctuating arsenic concentrations. We tested present model and triggering mechanisms by carrying out a series of modeling experiments where we used periodic pulses and sine-wave as featured exposures. Our results indicate that changes in the dominant frequencies and pulse timing can shift the safe rate distributions for tilapia, but not for that of freshwater clam. We found that tilapia increase bioenergetic costs to maintain the acclimation during pulsed and sine-wave exposures. Our ability to predict the consequences of physiological variation under time-varying exposure patterns has also implications for optimizing species growing, cultivation strategies, and risk assessment in realistic situations. - Systems-level modeling the pulsed and fluctuating arsenic exposures.

200

Systems-level modeling the effects of arsenic exposure with sequential pulsed and fluctuating patterns for tilapia and freshwater clam  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper was to use quantitative systems-level approach employing biotic ligand model based threshold damage model to examine physiological responses of tilapia and freshwater clam to sequential pulsed and fluctuating arsenic concentrations. We tested present model and triggering mechanisms by carrying out a series of modeling experiments where we used periodic pulses and sine-wave as featured exposures. Our results indicate that changes in the dominant frequencies and pulse timing can shift the safe rate distributions for tilapia, but not for that of freshwater clam. We found that tilapia increase bioenergetic costs to maintain the acclimation during pulsed and sine-wave exposures. Our ability to predict the consequences of physiological variation under time-varying exposure patterns has also implications for optimizing species growing, cultivation strategies, and risk assessment in realistic situations. - Systems-level modeling the pulsed and fluctuating arsenic exposures.

Chen, W.-Y. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, J.-W. [Institute of Ecology and Evolutionary Ecology, China Medical University, Taichung 40402, Taiwan (China); Ju, Y.-R. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Liao, C.-M., E-mail: cmliao@ntu.edu.t [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

2010-05-15

201

Drought-trigger ground-water levels and analysis of historical water-level trends in Chester County, Pennsylvania  

Science.gov (United States)

The Chester County observation-well network was established in 1973 through a cooperative agreement between the Chester County Water Resources Authority (CCWRA) and the U.S. Geological Survey. The network was established to monitor local ground-water levels, to determine drought conditions, and to monitor ground-water-level trends. Drought-warning and drought-emergency water-level triggers were determined for 20 of the 23 wells in the Chester County observation-well network. A statistical test to determine either rising or declining water-level trends was performed on data for all wells in the network. Water-level data from both of these wells showed a rising trend. A decrease in ground-water pumping in the area near these wells was probably the reason for the rise in water levels.

Schreffler, Curtis L.

1996-01-01

202

Supersonic water level measuring method and device therefor  

International Nuclear Information System (INIS)

In the present invention, water level can be measured stably irrespective of change of temperature distribution and flowing distribution of water in a pressure vessel or a tank of a nuclear reactor. Namely, sinusoidal supersonic waves are sent to a waveguide in contact with water to vibrate it. The water level is measured based on the change of the resonance state of the waveguide. Alternatively, sinusoidal supersonic waves are sent and received by a supersonic transducer. Resonance state of a waveguide in contact with water and connected to the supersonic transducer for propagating the supersonic waves is detected by way of the supersonic transducer. The water level is calculated based on the change of the resonance state. Since the resonance state of the waveguide member is free from the effects of temperature distribution and flowing distribution in water and gas, the water level can be measured at high accuracy irrespective of the temperature distribution and flowing distribution in water. (I.S.)

203

Water levels in the Yucca Mountain area, Nevada, 1993  

International Nuclear Information System (INIS)

Water levels were monitored in 28 wells in the Yucca Mountain area, Nevada, during 1993. Seventeen wells were monitored periodically, generally on a monthly basis, and 11 wells representing 18 intervals were monitored hourly. All wells monitor water levels in Tertiary volcanic rocks, except one that monitors water levels in Paleozoic carbonate rocks. Water levels were measured using calibrated steel tapes and pressure transducers; steel-tape measurements were corrected for mechanical stretch, thermal expansion, and borehole deviation to obtain precise water-level altitudes. Water-level altitudes in the Tertiary volcanic rocks ranged from about 728 meters above sea level east of Yucca Mountain to about 1,034 meters above sea level north of Yucca Mountain. Water-level altitudes in the well monitoring the Paleozoic carbonate rocks varied between 752 and 753 meters above sea level during 1993. Water levels were an average of about 0.04 meter lower than 1992 water levels. All data were acquired in accordance with a quality-assurance program to support the reliability of the data

204

Development of reactor water level sensor for extreme conditions  

International Nuclear Information System (INIS)

In the Fukushima accident, measurement failure of water level was one of the most important factors which caused serious situation. The differential pressure type water level indicators are widely used in various place of nuclear power plant but after the accident of TMI-2, the need of other reliable method has been required. The BICOTH type and the TRICOTH type water level indicator for light water power reactors had been developed for in-pile water level indicator but currently those are not adopted to nuclear power plant. In this study, the development of new type water level indicator composed of thermocouple and heater is described. Demonstration test and characteristic evaluation of the water level indicator were performed and we had obtained satisfactory results. (author)

205

Non-equilibrium probing of two-level charge fluctuators using the step response of a single electron transistor  

OpenAIRE

We report a new method to study two level fluctuators (TLFs) by measuring the offset charge induced after applying a sudden step voltage to the gate electrode of a single electron transistor. The offset charge is measured for more than 20 hours for samples made on three different substrates. We find that the offset charge drift follows a logarithmic increase over four orders of magnitude in time and that the logarithmic slope increases linearly with the step voltage. The cha...

Pourkabirian, A.; Gustafsson, M. V.; Johansson, G.; Clarke, J.; Delsing, P.

2014-01-01

206

On the applicability of available methods for estimating daily evapotranspiration by using diurnal water table fluctuations  

Science.gov (United States)

Shallow groundwater is mainly discharged by phreatophytes in many riparian ecosystems of arid and semiarid environment, while estimation of groundwater evapotranspiration (ETG) in these regions still remains a challenge for regional water resources assessment. Since White (1932) provided a method for estimating ETG based on diurnal groundwater dynamics, a number of modifications of White method were developed for calculating ETG; however, a major source of uncertainty in all these methods is associated with estimates groundwater recovery rate. In this study, we developed a criterion of quasi-steady conditions of groundwater evapotranspiration processes, which based on a coupled consideration of the water and energy balance. This criterion was tested by using the one dimensional saturated-unsaturated flow model, and use of these guidelines with the White method approaches could enable minimize uncertainty in estimating ETG. The developed methodology is illustrated by estimation of ETG rate using high-accuracy monitoring data of groundwater fluctuations for Goby environments in a typical arid region of northwest China.

Wang, P.; Pozdniakov, S. P.; Lekhov, M.; Yu, J.

2012-12-01

207

Suppression device for the reactor water level lowering  

International Nuclear Information System (INIS)

Purpose: To suppress the lowering in the reactor water level so as to avoid unnecessary actuation of ECCS upon generation of transient changes which forecasts the lowering of the reactor water level in a BWR type reactor. Constitution: There are provided a water level suppression signal generator for generating a water level suppression signal upon generation of a transient change signal which forecasts the water level lowering in a nuclear reactor and a recycling flow rate controller that applies a recycling flow rate control signal to a recycling pump drive motor by the water level lowering suppression signal. The velocity of the recycling pump is controlled by a reactor scram signal by way of the water level lowering suppresion signal generator and a recycling flow rate controller. Then, the recycling reactor core flow rate is decreased and the void amount in the reactor is transiently increased where the water level tends to increase. Accordingly, the water level lowering by the scram is moderated by the increasing tendency of the water level. (Ikeda, J.)

208

Soil- and plant- water uptake in saline environments and their consequences to plant adaptation in fluctuating climates  

Science.gov (United States)

Ecological processes determining plant colonization are quite peculiar and competition among different species is governed by a set of unique adaptations to stress conditions caused by drought, hypoxic or hyper-saline conditions. These adaptations and possible positive feedbacks often lead to the formation of patterns of vegetation colonization and spatial heterogeneity (zonation), and play a primary role in the stabilization of sediments. It is these issues that frame the scope of this study. The main objective of this work is to track one of the fundamental pathways between plant adaptation (quantified in terms of physiological and ecological attributes such as leaf area or root density profile) and feedbacks (quantified by plant-mediated alterations to water availability and salinity levels): root water uptake. Because root-water uptake is the main conduit connecting transpiring leaves to reservoirs of soil water, the means by which salinity modifies the processes governing its two end-points and any two-way interactions between them serves as a logical starting point. Salinity effects on leaf transpiration and photosynthesis are first explored via stomatal optimization principles that maximize carbon gain at a given water loss for autonomous leaves. Salinity directly affects leaf physiological attributes such as mesophyll conductance and photosynthetic parameters and hence over-all conductance to transpiration as well as different strategies to cope with the high salinity (e.g. through salt seclusion, compartmentation and osmotic adjustments). A coupled model of subsurface flow based on a modified Richards’ equation that accounts for the effects of increasing salinity, anaerobic conditions, water stress and compensation factors is developed. Plant water uptake is considered as a soil moisture sink term with a potential rate dictated by the carbon demands of the leaves, and an actual rate that accounts for both - hydraulic and salinity limitations. Using this model, the root distribution shape function (e.g. constant, linear, exponential, or power-law) that optimally satisfies these carbon demands and simultaneous hydraulic and salinity constraints of the soil-root system is then determined for a set of forcing variables and boundary conditions. Adaptation speeds and feedback strengths to future climatic fluctuations are explored as ‘departures’ from this equilibrium profile state.

Volpe, V.; Albertson, J. D.; Katul, G. G.; Marani, M.

2010-12-01

209

Effects of water level regulation on littoral zone of lakes Konnivesi and Ruotsalainen  

International Nuclear Information System (INIS)

Measures to develop an ecologically based regulation practice for the lakes Ruotsalainen and Konnivesi which belong to the Kymijoki watercourse, were undertaken in 1995, when the intermunicipal board for the Heinola health care centre and Myllykoski Oy proposed that the regulation licence should re-evaluated. The purpose of this study, which is part of the overall development project, was to assess the ecological impacts of regulation on the littoral zones of these lakes. More specifically, the study focussed on the changes in the ecology of the littoral zone due to the water level fluctuation. The littoral vegetation of lake Konnivesi reflects the improvement of water quality over the past fifteen years. The species indicative of eutrophication have mostly disappeared. The vegetation of the uppermost littoral zone has stabilised, and the effect of wave erosion is small Ice pressure on the bottom has hardly any impact on the plants sensitive to the ice scouring effect, because the ice-covered zone has actually been reduced in size consequent to the regulation. Owing to the small range of water level fluctuation during the open water period, the uppermost littoral zone remains very narrow, which restricts the spreading of especially helophytic vegetation. The narrow littoral zone impairs the development of the normal zonal biotope in many places and simultaneously prevents diverse increase of littoral biota. The aim of the ecological regulation practice proposed for Koogical regulation practice proposed for Konnivesi is to ensure a water level favourable for pike spawning It is further proposed that the water level should decline by 25 cm during the open water period following the flood peak. This would help to widen the littoral zone suited to helophytic vegetation and to increase the vegetational diversity of especially gently sloping shores. (orig.) 12 refs

210

Water level influences on body condition of Geophagus brasiliensis (Perciformes: Cichlidae in a Brazilian oligotrophic reservoir  

Directory of Open Access Journals (Sweden)

Full Text Available Effects of water level fluctuations on body condition of Geophagus brasiliensis were studied in a 30 km² Brazilian oligotrophic reservoir. Physiological condition (K and gonadosomatic index (GSI were compared according to water level (low and high. Females' best conditions were associated to higher resources availability during high water, since gonad development did not change between low and high water. Males' condition did not change between water levels, while the highest gonad development occurred in low water. Females presented higher reproductive investment than males, which allocated most of energy for somatic development. This strategy could be a mechanism to undergo the stress caused by oligotrophic characteristics of the reservoir enhanced during low water level.Efeitos do nível da água na condição de Geophagus brasiliensis foram analisados em um reservatório oligotrófico. A condição fisiológica (K e o índice gonadossomático (IGS foram comparados entre os níveis da água (baixo e alto. Melhores condições de fêmeas foram associadas a maiores disponibilidades de recursos no nível alto, já que o desenvolvimento gonadal não variou. Não foram registradas diferenças na condição de machos, contudo maiores valores de IGS ocorreram no nível baixo. Fêmeas apresentaram elevado investimento reprodutivo, enquanto machos investiram mais no desenvolvimento somático. Tal estratégia pode ser um mecanismo para suportar o estresse causado pelas características oligotróficas do reservatório, intensificadas durante o período de níveis baixos da água.

Alejandra Filippo Gonzalez Neves dos Santos

2004-09-01

211

The effect of wind speed fluctuations on the performance of a wind-powered membrane system for brackish water desalination  

OpenAIRE

A wind-powered reverse osmosis membrane (wind-membrane) system without energy storage was tested using synthetic brackish water (2750 and 5500 mg/L NaCl) over a range of simulated wind speeds under both steady-state and fluctuating conditions. The parameters varied were: i) average wind speed from 3.7 (system start-up) to 8.7 m/s; ii) wind turbulence intensity from 0.0 (steady-state conditions) to 0.6 (extreme fluctuations); and iii) period of oscillation from 15 to 90 s. With ...

Park, Gavin L.; Scha?fer, Andrea; Richards, Bryce S.

2011-01-01

212

Effects of Water Levels on Productivity of Canada Geese in the Northern Flathead Valley, Final Report.  

Energy Technology Data Exchange (ETDEWEB)

The Fish and Wildlife Program of the Northwest Power Planning Council calls for wildlife mitigation at hydroelectric projects in the Columbia River System. Beginning April, 1984, the Bonneville Power Administration funded a study of the effects of the operation of Hungry Horse and Kerr Dams on the western Canada goose (Branta canadensis moffittii) inhabitating the Flathead Valley of northwest Montana. The study was conducted by personnel of the Montana Department of Fish, Wildlife and Parks (MDFWP), to: (1) identify the size and productivity of this population, (2) identify current habitat conditions and losses of nesting and brood-rearing areas, (3) describe the effects of water level fluctuations on nesting and brood-rearing, and (4) identify mitigation alternatives to offset these effects. Annual pair and nest surveys were used to document the location and fate of goose nests. The number of known nesting attempts varied from 44 in 1984 to 108 in 1985, to 136 in 1986 and 134 in 1987. Fifty-four percent of the annual meeting nesting effort took place on elevated sites which were secure from the flooding and dewatering effects of fluctuating water levels. An average of 15 nests were found on stumps in the remnant Flathead River delta, however, an area strongly influenced by the operation of Kerr Dam. Annual nest losses to flooding and predation attributable to fluctuations caused by the dam were recorded. 53 refs., 24 figs., 35 tabs.

Casey, Daniel

1987-08-01

213

Terrestrial waters and sea level variations on interannual time scale  

OpenAIRE

On decadal to multidecadal time scales, thermal expansion of sea waters and land ice loss are the main contributors to sea level variations. However, modification of the terrestrial water cycle due to climate variability and direct anthropogenic forcing may also affect sea level. For the past decades, variations in land water storage and corresponding effects on sea level cannot be directly estimated from observations because these are almost unexistent at global continental scale. However, g...

Llovel, W.; Becker, M.; Cazenave, A.; Jevrejeva, S.; Alkama, R.; Decharme, B.; Douville, H.; Ablain, M.; Beckley, B.

2011-01-01

214

Nonequilibrium Probing of Two-Level Charge Fluctuators Using the Step Response of a Single-Electron Transistor  

Science.gov (United States)

We report a new method to study two-level fluctuators (TLFs) by measuring the offset charge induced after applying a sudden step voltage to the gate electrode of a single-electron transistor. The offset charge is measured for more than 20 h for samples made on three different substrates. We find that the offset charge drift follows a logarithmic increase over 4 orders of magnitude in time and that the logarithmic slope increases linearly with the step voltage. The charge drift is independent of temperature, ruling out thermally activated TLFs and demonstrating that the charge fluctuations involve tunneling. These observations are in agreement with expectations for an ensemble of TLFs driven out of equilibrium. From our model, we extract the density of TLFs assuming either a volume density or a surface density.

Pourkabirian, A.; Gustafsson, M. V.; Johansson, G.; Clarke, J.; Delsing, P.

2014-12-01

215

Water levels in the Yucca Mountain area, Nevada, 1994  

International Nuclear Information System (INIS)

Water levels were monitored in 28 wells in the Yucca Mountain area, Nevada, during 1994. Twelve wells representing 13 intervals were monitored periodically, generally on a monthly basis, 6 wells representing 10 intervals were monitored hourly, and 10 wells representing 13 intervals were monitored both periodically and hourly. All wells monitor water levels in Tertiary volcanic rocks, except one, that monitors water levels in Paleozoic carbonate rocks. Water levels were measured using calibrated steel tapes, a multiconductor cable unit, and pressure transducers. Water-level altitudes in the Tertiary volcanic rocks ranged from about 728 to about 1,034 meters above sea level during 1994. The mean-annual water-level altitude in the well monitoring the Paleozoic carbonate rocks was about 753 meters above sea level during 1994. Water levels were only an average of about 0.01 meters lower than 1993 water levels. All data were acquired in accordance with a quality-assurance program to support the reliability of the data

216

Water levels in the Yucca Mountain area, Nevada, 1995  

International Nuclear Information System (INIS)

Water levels were monitored in 28 wells in the Yucca Mountain area, Nevada, during 1995. Seventeen wells representing 18 depth intervals were monitored periodically, generally on a monthly basis, 2 wells representing 3 depth intervals were monitored hourly, and 9 wells representing 15 depth intervals were monitored both periodically and hourly. All wells monitor water levels in Tertiary volcanic rocks except one that monitors water levels in Paleozoic carbonate rocks. Water levels were measured using calibrated steel tapes, a multiconductor cable unit, and/or pressure transducers. Mean water-level altitudes in the Tertiary volcanic rocks ranged from about 728 to about 1,034 meters above sea level during 1995. The mean water-level altitude in the well monitoring the Paleozoic carbonate rocks was about 753 meters above sea level during 1995. Mean water level altitudes were only an average of about 0.01 meters higher than 1994 mean water level altitudes. A single-well aquifer test was conducted on well UE-25 WT number-sign 12 during August and September 1995. Well USW 0-2 was also pumped during October and November 1995, in preparation for single-well aquifer test at that well. All data were acquired in accordance with a quality-assurance program to support the reliability of the data

217

Analysis of water level control methods for nuclear steam generator  

International Nuclear Information System (INIS)

Nuclear steam generator (SG) is a highly complex nonlinear time-changed system. The inverse dynamics effects, which are caused by shrink and swell under transient, startup and lower power operation, make the water level difficult to control. Methods of SG water level control are analyzed. The shortcoming of conventional PI(D) control for SG level is pointed out. It emphatically expounds the fuzzy logic control and the neural network control to nuclear steam generator level. Finally, the author brings forward his opinion upon the advance tendency of SG water level control. (authors)

218

EFECTOS DE LA FLUCTUACIÓN DEL NIVEL DEL AGUA SOBRE LA ESTRUCTURA DEL ENSAMBLAJE DE ROTÍFEROS EN EL LAGO LARGO (SISTEMA YAHUARCACA - LLANURA DE INUNDACIÓN DEL RÍO AMAZONAS - COLOMBIA) / Effects of water level fluctuation on rotifers assemblage structure in Largo lake (Yahuarcaca sistem - river Amazon floodplain - Colombia)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Se realizó un reconocimiento taxonómico y estimación de la densidad en el ensamblaje de rotíferos en el lago Largo, del sistema de lagos Yahuarcaca, en la ribera colombiana del río Amazonas, a partir de muestreos en las fases hidrológicas de aguas bajas, ascenso y descenso. Se identificaron 68 espec [...] ies, 28 de ellas son nuevos registros para ambientes colombianos. Se encontró aumento en la riqueza en las épocas de ascenso y descenso, siendo mayor en la zona litoral respecto de la limnética, y la tendencia a mayor similitud taxonómica entre ambas zonas en el periodo de aguas bajas, debido al mínimo desarrollo de macrófitas en esta fase y la consecuente menor heterogeneidad espacial. Se observó el predominio de rotíferos con trofi adaptados para moler y triturar partículas (maleado y maleorramado) en las épocas de aguas bajas (Brachionus ahlstromi) y descenso (Filina saltator) y en la época de ascenso de Polyarthra vulgaris, con trofi adaptado para perforar y succionar fluidos de algas y otros organismos (virgado) y apéndices que favorecen la rápida natación. En general, se establecieron posibles relaciones entre la riqueza y la densidad de rotíferos con cambios en características como el desarrollo de vegetación acuática en el litoral, profundidad del lago, nivel de conectividad con los otros lagos del sistema Yahuarcaca, influencia de aguas blancas del Amazonas y negras de origen local, potenciales recursos nutricionales y depredadores, y posible efecto de arrastre por la corriente. Abstract in english We conducted a taxonomic recognition and density estimation of the assemblage of rotifers in Lake Largo, in the floodplain system of Yahuarcaca, connected with the Amazon River, in Colombia. Two samplings were made for each hydrological phase (low water, filling and draining phases); 68 species were [...] identified, 28 of them are new records for Colombian environments. We found an increased in species richness in the filling and draining phases, being higher in the littoral than in limnetic region, and a tendency to a higher taxonomic similarity between the two areas during low water periods, due to the reduced macrophyte development in that period and consequent reduced spatial heterogeneity. We observed the predominance of rotifers with trophi adapted for grinding and crushing particles (malleate and malleorramate) in low water phase (Brachionus ahlstromi) and draining phase (Filina saltator) and Polyarthra vulgaris, with a trophi adapted to pierce and suck out the fluids of algae and other organisms (virgate), and appendices that support the rapid swimming, at the filling phase. In general, we established possible relations between rotifers richness and density with changes in characteristics as the development of aquatic vegetation in the littoral zone, lake depth, level of connectivity with other lakes of Yahuarcaca system, level of influence of white waters from the Amazon river, and black waters from local origin, potentials nutritional resources and predators, and drag effect by the current.

CAMILO, ANDRADE-SOSSA; MIGDALIA, GARCÍA-FOLLECO; CARLOS A., RODRÍGUEZ-MUNAR; SANTIAGO R., DUQUE; EMILIO, REALPE.

2011-12-30

219

Sensitivity of polarization fluctuations to the nature of protein-water interactions: Study of biological water in four different protein-water systems  

Science.gov (United States)

Since the time of Kirkwood, observed deviations in magnitude of the dielectric constant of aqueous protein solution from that of neat water (˜80) and slower decay of polarization have been subjects of enormous interest, controversy, and debate. Most of the common proteins have large permanent dipole moments (often more than 100 D) that can influence structure and dynamics of even distant water molecules, thereby affecting collective polarization fluctuation of the solution, which in turn can significantly alter solution's dielectric constant. Therefore, distance dependence of polarization fluctuation can provide important insight into the nature of biological water. We explore these aspects by studying aqueous solutions of four different proteins of different characteristics and varying sizes, chicken villin headpiece subdomain (HP-36), immunoglobulin binding domain protein G (GB1), hen-egg white lysozyme (LYS), and Myoglobin (MYO). We simulate fairly large systems consisting of single protein molecule and 20000-30000 water molecules (varied according to the protein size), providing a concentration in the range of ˜2-3 mM. We find that the calculated dielectric constant of the system shows a noticeable increment in all the cases compared to that of neat water. Total dipole moment auto time correlation function of water ??MW(0)?MW(t)? is found to be sensitive to the nature of the protein. Surprisingly, dipole moment of the protein and total dipole moment of the water molecules are found to be only weakly coupled. Shellwise decomposition of water molecules around protein reveals higher density of first layer compared to the succeeding ones. We also calculate heuristic effective dielectric constant of successive layers and find that the layer adjacent to protein has much lower value (˜50). However, progressive layers exhibit successive increment of dielectric constant, finally reaching a value close to that of bulk 4-5 layers away. We also calculate shellwise orientational correlation function and tetrahedral order parameter to understand the local dynamics and structural re-arrangement of water. Theoretical analysis providing simple method for calculation of shellwise local dielectric constant and implication of these findings are elaborately discussed in the present work.

Ghosh, Rikhia; Banerjee, Saikat; Hazra, Milan; Roy, Susmita; Bagchi, Biman

2014-12-01

220

Sensitivity of polarization fluctuations to the nature of protein-water interactions: study of biological water in four different protein-water systems.  

Science.gov (United States)

Since the time of Kirkwood, observed deviations in magnitude of the dielectric constant of aqueous protein solution from that of neat water (?80) and slower decay of polarization have been subjects of enormous interest, controversy, and debate. Most of the common proteins have large permanent dipole moments (often more than 100 D) that can influence structure and dynamics of even distant water molecules, thereby affecting collective polarization fluctuation of the solution, which in turn can significantly alter solution's dielectric constant. Therefore, distance dependence of polarization fluctuation can provide important insight into the nature of biological water. We explore these aspects by studying aqueous solutions of four different proteins of different characteristics and varying sizes, chicken villin headpiece subdomain (HP-36), immunoglobulin binding domain protein G (GB1), hen-egg white lysozyme (LYS), and Myoglobin (MYO). We simulate fairly large systems consisting of single protein molecule and 20000-30000 water molecules (varied according to the protein size), providing a concentration in the range of ?2-3 mM. We find that the calculated dielectric constant of the system shows a noticeable increment in all the cases compared to that of neat water. Total dipole moment auto time correlation function of water ??MW(0)?MW(t)? is found to be sensitive to the nature of the protein. Surprisingly, dipole moment of the protein and total dipole moment of the water molecules are found to be only weakly coupled. Shellwise decomposition of water molecules around protein reveals higher density of first layer compared to the succeeding ones. We also calculate heuristic effective dielectric constant of successive layers and find that the layer adjacent to protein has much lower value (?50). However, progressive layers exhibit successive increment of dielectric constant, finally reaching a value close to that of bulk 4-5 layers away. We also calculate shellwise orientational correlation function and tetrahedral order parameter to understand the local dynamics and structural re-arrangement of water. Theoretical analysis providing simple method for calculation of shellwise local dielectric constant and implication of these findings are elaborately discussed in the present work. PMID:25494802

Ghosh, Rikhia; Banerjee, Saikat; Hazra, Milan; Roy, Susmita; Bagchi, Biman

2014-12-14

221

Control of Effective Productive Capacity with a Level of Total Production Inventory in a Business Fluctuation Period  

Science.gov (United States)

This paper analyzes a relation between level of total production inventory and effective production capacity in a production process, and proposes a method of controlling effective production capacity in a business fluctuations period. They are based on the property: “effective production capacity = capacity of production facilities - total changeover loss", where changeover loss is a decreasing function of level of total production inventory. Although the effective production capacity can be controlled by an increase or decrease of production facilities, its cost is too expensive. It must be done only in the case that an increase or decrease in demand is confirmed. Therefore, the effective production capacity must be controlled by the level of total inventory. In a business recovery or recession period, two kinds of production time have to be controlled. The first the production-time control for the increase or decrease in demand, and the second is that for an increase or decrease in the level of total inventory. Even if an increasing or decreasing rate in demand is constant, the value of the total control time decreases at first and then increases exponentially. This is the reason why inventory control is difficult in a business fluctuations period.

Ishitani, Shigeki; Mitsumori, Sadamichi

222

Synthesis water level control by fuzzy logic  

OpenAIRE

Purpose: This paper focuses on evolving of two types fuzzy and classical PID liquid level controller and examining whether they are better able to handle modelling uncertainties. A two stage strategy is employed to design the synthesis fuzzy and classical PID controller with the process of the first and second order and implements disorder (quadratic function).Design/methodology/approach: The synthesis of fuzzy and classical PID liquid level controller was realized with the HP laptop 6830s Co...

Berk, P.; Stajnko, D.; Vindis, P.; Mursec, B.; Lakota, M.

2011-01-01

223

Short-time variations of the ground water level  

International Nuclear Information System (INIS)

Investigations have demonstrated that the ground water level of aquifers in the Swedish bedrock shows shorttime variations without changing their water content. The ground water level is among other things affected by regular tidal movements occuring in the ''solid'' crust of the earth variations in the atmospheric pressure strong earthquakes occuring in different parts of the world These effects proves that the system of fissures in the bedrock are not stable and that the ground water flow is influenced by both water- and airfilled fissures

224

Intraocular pressure fluctuation in healthy and glaucomatous eyes: a comparative analysis between diurnal curves in supine and sitting positions and the water drinking test.  

Science.gov (United States)

Purpose: To compare intraocular pressure (IOP) using the simplified daily tensional curve (SDTC) between supine and sitting positions in terms of peak levels and amount of fluctuation in both, glaucomatous and healthy subjects. The secondary endpoint was the comparison of these measures with those derived from the water drinking test (WDT). Methods: Thirty patients with primary open-angle glaucoma (POAG) that were undergoing medical therapy and 30 healthy subjects were enrolled in this study. Each patient underwent a diurnal curve between 8 am and 4 pm. After lying down for 5 minutes, the IOP was measured with the Perkins tonometer. Patients were instructed to sit in the upright position for 5 minutes and the tonometry was repeated. At 4:15 pm, the WDT test was performed. Fluctuation was defined as the difference between the highest and the lowest IOP readings (range). The Student's t test was used to assess differences and a P value <0.05 was considered to be statistically significant. Results: The diurnal curve in the supine position demonstrated higher IOP average values (on average 3-4 mmHg higher) compared to the sitting position (p<0.0001) for both groups. IOP peaks were higher in the supine position; however, the IOP range was essentially the same between the three methods. Treated glaucomatous patients had higher IOP levels in all measurements, but the fluctuation for all tests performed appeared to be similar to that of healthy patients. Conclusion: The data suggested that WDT can be used to estimate the diurnal IOP peak and fluctuation observed in the SDTC of the supine position for treated glaucomatous patients. Further studies can compare the possible correlation between the WDT results and those obtained from nocturnal supine measurements. PMID:25494373

Caiado, Rafael Ramos; Badaró, Emmerson; Kasahara, Niro

2014-10-01

225

Lake-Level Variability and Water Availability in the Great Lakes  

Science.gov (United States)

Summary In this report, we present recorded and reconstructed (pre-historical) changes in water levels in the Great Lakes, relate them to climate changes of the past, and highlight major water-availability implications for storage, coastal ecosystems, and human activities. 'Water availability,' as conceptualized herein, includes a recognition that water must be available for human and natural uses, but the balancing of how much should be set aside for which use is not discussed. The Great Lakes Basin covers a large area of North America. The lakes capture and store great volumes of water that are critical in maintaining human activities and natural ecosystems. Water enters the lakes mostly in the form of precipitation and streamflow. Although flow through the connecting channels is a primary output from the lakes, evaporation is also a major output. Water levels in the lakes vary naturally on timescales that range from hours to millennia; storage of water in the lakes changes at the seasonal to millennial scales in response to lake-level changes. Short-term changes result from storm surges and seiches and do not affect storage. Seasonal changes are driven by differences in net basin supply during the year related to snowmelt, precipitation, and evaporation. Annual to millennial changes are driven by subtle to major climatic changes affecting both precipitation (and resulting streamflow) and evaporation. Rebounding of the Earth's surface in response to loss of the weight of melted glaciers has differentially affected water levels. Rebound rates have not been uniform across the basin, causing the hydrologic outlet of each lake to rise in elevation more rapidly than some parts of the coastlines. The result is a long-term change in lake level with respect to shoreline features that differs from site to site. The reconstructed water-level history of Lake Michigan-Huron over the past 4,700 years shows three major high phases from 2,300 to 3,300, 1,100 to 2,000, and 0 to 800 years ago. Within that record is a quasi-periodic rise and fall of about 160 ? 40 years in duration and a shorter fluctuation of 32 ? 6 years that is superimposed on the 160-year fluctuation. Recorded lake-level history from 1860 to the present falls within the longer-term pattern and appears to be a single 160-year quasi-periodic fluctuation. Independent investigations of past climate change in the basin over the long-term period of record confirm that most of these changes in lake level were responses to climatically driven changes in water balance, including lake-level highstands commonly associated with cooler climatic conditions and lows with warm climate periods. The mechanisms underlying these large hydroclimatic anomalies are not clear, but they may be related to internal dynamics of the ocean-atmosphere system or dynamical responses of the ocean-atmosphere system to variability in solar radiation or volcanic activity. The large capacities of the Great Lakes allow them to store great volumes of water. As calculated at chart datum, Lake Superior stores more water (2,900 mi3) than all the other lakes combined (2,539 mi3). Lake Michigan's storage is 1,180 mi3; Lake Huron's, 850 mi3; Lake Ontario's, 393 mi3; and Lake Erie's, 116 mi3. Seasonal lake-level changes alter storage by as much as 6 mi3 in Lake Superior and as little as 2.1 mi3 in Lake Erie. The extreme high and low lake levels measured in recorded lake-level history have altered storage by as much as 31 mi3 in Lake Michigan-Huron and as little as 9 mi3 in Lake Ontario. Diversions of water into and out of the lakes are very small compared to the total volume of water stored in the lakes. The water level of Lake Superior has been regulated since about 1914 and levels of Lake Ontario since about 1960. The range of Lake Superior water-level fluctuations and storage has not been altered greatly by regulation. However, fluctuations on Lake Ontario have been reduced from 6.6 ft preregulation

Wilcox, Douglas A.; Thompson, Todd A.; Booth, Robert K.; Nicholas, J.R.

2007-01-01

226

Temporal scaling behavior of sea-level change in Hong Kong - Multifractal temporally weighted detrended fluctuation analysis  

Science.gov (United States)

The rise in global sea levels has been recognized by many scientists as an important global research issue. The process of sea-level change has demonstrated a complex scaling behavior in space and time. Large numbers of tide gauge stations have been built to measure sea-level change in the North Pacific Ocean, Indian Ocean, North Atlantic Ocean, and Antarctic Ocean. Extensive studies have been devoted to exploring sea-level variation in Asia concerning the Bohai Gulf (China), the Yellow Sea (China), the Mekong Delta (Thailand), and Singapore. Hong Kong, however, a mega city with a population of over 7 million situated in the mouth of the Pear River Estuary in the west and the South China Sea in the east, has yet to be studied, particularly in terms of the temporal scaling behavior of sea-level change. This article presents an approach to studying the temporal scaling behavior of sea-level change over multiple time scales by analyzing the time series of sea-level change in Tai Po Kou, Tsim Bei Tsui, and Quarry Bay from the periods of 1964-2010, 1974-2010, and 1986-2010, respectively. The detection of long-range correlation and multi-fractality of sea-level change seeks answers to the following questions: (1) Is the current sea-level rise associated with and responsible for the next rise over time? (2) Does the sea-level rise have specific temporal patterns manifested by multi-scaling behaviors? and (3) Is the sea-level rise is temporally heterogeneous in the different parts of Hong Kong? Multi-fractal temporally weighted de-trended fluctuation analysis (MF-TWDFA), an extension of multi-fractal de-trended fluctuation analysis (MF-DFA), has been applied in this study to identify long-range correlation and multi-scaling behavior of the sea-level rise in Hong Kong. The experimental results show that the sea-level rise is long-range correlated and multi-fractal. The temporal patterns are heterogeneous over space. This finding implies that mechanisms associated with the local ecological environment, hydrodynamic and morphodynamic processes, and human activities might have driven a distinct sea-level rise in Hong Kong.

Zhang, Yuanzhi; Ge, Erjia

2013-01-01

227

Quality Level of Bottled Drinking Water Consumed in Saudi Arabia  

OpenAIRE

The quality of drinking water is a universal health concern and access to safe water is a fundamental human right. Many national and international organizations set certain parameters and levels for Bottled Drinking Water (BDW) to ensure their quality. The present work aims to analyze the quality of various brands of BDW used in Saudi Arabia and to compare the quality levels to the BDW standards. One hundred and twenty six samples of 54 different BDW brands were ...

Khater, Ashraf E. M.; Asma Al-Jaloud; El-taher, A.

2014-01-01

228

Experimental study of the fluctuations of an upward air-water flow in the circular pipe  

International Nuclear Information System (INIS)

Among all the interactions between fluids and mechanical structures, the author is in particular interested in decoupled random excitations due to a two-phase flow on a transverse mechanical structure. The aim of this work is to know the parameters of the two-phase flow which drive the excitation forces of the vibrational modes of these structures. The fluctuations of an upward bubble two-phase flow have been studied in a cylindrical pipe with and without barrier(s). Three measurements techniques have been used to determine the mean characteristics of the flow and the fluctuations of the liquid mass flux and of the liquid movement quantity (nuclear magnetic resonance), of the local void fraction (optical probe) and of the wall pressure (piezoelectric sensor). The obtained results show that the fluctuations of the mass fluxes and of the liquid movement quantities are mainly driven by the fluctuations of the surface void fractions and particularly when the mean void fraction is great. Similarly, the pressure fluctuations are strongly influenced by the surface void fraction fluctuations. In the case of a barrier context, an instability phenomenon, inducing a sudden rise of the void fraction fluctuations in the range of the mean void fraction between 5 and 20 per cent, has been observed. The presence of grids leads to the formation of strong amplitude peaks of the pressure spectra. The study on the evolution of these peaks in terms of gas and liquid velocities implies that the pressure fluctuations, caused by the phenomenon of releases of these two-phase flows, are mainly controlled by the velocity of this mixture and by the fluctuations of the surface void fraction. (author)

229

Analysis of Ground-Water Levels and Associated Trends in Yucca Flat, Nevada Test Site, Nye County, Nevada, 1951-2003  

Energy Technology Data Exchange (ETDEWEB)

Almost 4,000 water-level measurements in 216 wells in the Yucca Flat area from 1951 to 2003 were quality assured and analyzed. An interpretative database was developed that describes water-level conditions for each water level measured in Yucca Flat. Multiple attributes were assigned to each water-level measurement in the database to describe the hydrologic conditions at the time of measurement. General quality, temporal variability, regional significance, and hydrologic conditions are attributed for each water-level measurement. The database also includes narratives that discuss the water-level history of each well. Water levels in 34 wells were analyzed for variability and for statistically significant trends. An attempt was made to identify the cause of many of the water-level fluctuations or trends. Potential causes include equilibration following well construction or development, pumping in the monitoring well, withdrawals from a nearby supply well, recharge from precipitation, earthquakes, underground nuclear tests, land subsidence, barometric pressure, and Earth tides. Some of the naturally occurring fluctuations in water levels may result from variations in recharge. The magnitude of the overall water-level change for these fluctuations generally is less than 2 feet. Long-term steady-state hydrographs for most of the wells open to carbonate rock have a very similar pattern. Carbonate-rock wells without the characteristic pattern are directly west of the Yucca and Topgallant faults in the southwestern part of Yucca Flat. Long-term steady-state hydrographs from wells open to volcanic tuffs or the Eleana confining unit have a distinctly different pattern from the general water-level pattern of the carbonate-rock aquifers. Anthropogenic water-level fluctuations were caused primarily by water withdrawals and nuclear testing. Nuclear tests affected water levels in many wells. Trends in these wells are attributed to test-cavity infilling or the effects of depressurization following nuclear testing. The magnitude of the overall water-level change for wells with anthropogenic trends can be large, ranging from several feet to hundreds of feet. Vertical water-level differences at 27 sites in Yucca Flat with multiple open intervals were compared. Large vertical differences were noted in volcanic rocks and in boreholes where water levels were affected by nuclear tests. Small vertical differences were noted within the carbonate-rock and valley-fill aquifers. Vertical hydraulic gradients generally are downward in volcanic rocks and from pre-Tertiary clastic rocks toward volcanic- or carbonate-rock units.

J.M. Fenelon

2005-10-05

230

Annual fluctuations of endocrine-disrupting compounds at the lower end of the Lima River, Portugal, and in adjacent coastal waters.  

Science.gov (United States)

The Lima River is a Spanish–Portuguese water body. Notwithstanding the fact that the river incorporates protected natural areas, levels of endocrine-disrupting compounds (EDCs) within its waters have never been measured; such EDCs include the following: natural and pharmaceutical oestrogens (17?-estradiol, E1, and 17?-ethynylestradiol), industrial and household pollutants (4-octylphenol, 4-nonylphenol, and their monoethoxylates and diethoxylates, and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, genistein), and phytosterols (namely, sitosterol). To obtain an understanding of levels of EDCs, water samples were taken from eight sampling sites along the river every 2 months during a 1-year period (2011). The water samples were preconcentrated (Oasis HLB cartridges), cleaned (silica cartridges), and analysed using gas chromatography. Results showed that levels of oestrogens and industrial and household pollutants were higher in summer than in other seasons. Although oestrogens were more abundant (approximately 40 ng/L) on the southern margin of the river, levels of other pollutants were higher (approximately 124 ng/L) in the north. Phytoestrogens and sitosterol showed clear seasonal fluctuations with higher amounts of formononetin (approximately 389 ng/L), biochanin A (approximately 160 ng/L), and sitosterol (?5 µg/L) measured in summer. The overall oestrogenic load, expressed in ethynylestradiol equivalents, was 18 ng/L for oestrogens, 0.5 ng/L for industrial and household pollutants, and 13 ng/L for phytoestrogens. Water physicochemical parameters indicate anthropogenic pollution because ?nitrites,nitrates (>1 mg/L) and phosphates (approximately 0.4 mg/L) were high. The study showed that the waters of the Lima River are subject to impacts and that levels of EDCs pose risks to the river’s biota. PMID:25015732

Rocha, Maria João; Cruzeiro, Catarina; Peixoto, Cristiana; Rocha, Eduardo

2014-10-01

231

Synthesis water level control by fuzzy logic  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: This paper focuses on evolving of two types fuzzy and classical PID liquid level controller and examining whether they are better able to handle modelling uncertainties. A two stage strategy is employed to design the synthesis fuzzy and classical PID controller with the process of the first and second order and implements disorder (quadratic function.Design/methodology/approach: The synthesis of fuzzy and classical PID liquid level controller was realized with the HP laptop 6830s Compaq NA779ES, software Matlab/Simulink 2008b, FIS (Fuzzy Inference System soft logical tool, input-output unit 500 Dragon Rider and ultrasonic sensor. Using the simulation program Matlab/Simulink/FIS we simulate the operation of fuzzy and classical controller in the liquid level regulating cycle and made a comparison between fuzzy and classical controller functioning.Findings: From the responses to step fuzzy and classical controller for first-order process shows that the actual value of the controlled variable takes the value one. Fuzzy and classical PID controller does not allow control derogation, which is also inappropriate for fuzzy and classical control cycle with incorporating disturbance. Classical PID controller in the first-order process provides short-term regulation, such as fuzzy PID controller. In fuzzy control cycle with fuzzy PID controller and incorporating disturbance in the process of second-order the control cycle is stable and at certain predetermined parameters (integral gain a control does not allow deviations.Research limitations/implications: In future research, the robustness of the fuzzy logic controller will be investigated in more details.Practical implications: Using fuzzy liquid level controller can reduce power consumption by 25%. Originality/value: Fuzzy logic controller is useful in applications of nonlinear static characteristic, where classical methods with usually classical PID controllers cannot be a satisfactory outcome

P. Berk

2011-04-01

232

Water-Level Changes in Shallow Wells Before and After the 1999 Ýzmit and Düzce Earthquakes and Comparison with Long-Term Water-Level Observations (1999-2004), NW Turkey.  

Science.gov (United States)

It is well known that earthquakes cause hydrological changes, such as drying or flooding of water wells, fluctuations in ground-water levels in wells, changes in water quality, and formation of new springs. Significant drops in ground-water levels in wells were recorded during recent earthquakes in NW Turkey on August 17, 1999 in Ýzmit and on November 12, 1999 in Düzce. The Ýzmit earthquake (Ms 7.4) caused pre-seismic water-level changes in wells at Eskisehir, located 118-216 km away from the epicentre. Well-level changes in the Eskisehir, Sakarya, Bursa, Yalova, Yenisehir and Ýnegöl basins were recorded prior to and after the Düzce earthquake (Ms 7.2) as well. These changes are due to strain on the southern Marmara segments of the Thrace-Eskisehir Fault Zone (TEFZ), which is affected by deformation of the North Anatolian Fault Zone (NAFZ). Ground-water-level changes in wells prior to and after the earthquake away from the epicentre and the position of Eastern Marmara-Eskisehir region indicate a possible connection between well-level changes that respond to compressive and tensile stresses and shear strain away from active strike-slip faults. The wells, located in basins having an angular connection with the earthquake-producing main faults, completely activate only during major earthquakes. The wells showing anomalies prior to earthquakes are generally found near epicentres or in basins having an angular connection as stated above. The data collected after the 1999 anomalies up to September 2004 indicate that the 1999 anomalies are unique to that year. It was not difficult to separate the seasonal fluctuations of the water levels from the earthquake anomalies. In this context, it is concluded that the 1999 water level anomalies prior to the earthquake were the fast- and short-period signature of slow but long-term deformations that occurred over a large area.

Yaltirak, Cenk; Yalçin, Tolga; Yüce, Galiip; Bozkurto?lu, Erkan

2005-12-01

233

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

International Nuclear Information System (INIS)

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

234

Short-term water and suspended-sediment fluctuations in a Louisiana marsh  

Science.gov (United States)

To determine the timing of and driving forces for sediment suspension and deposition and the effect of impoundment, three self-recording instrument packages were deployed in a section of Louisiana marsh. Two of the packages went into an impoundment and one into an adjacent open, or control, area. A data logger in the package controlled sensors to measure water level, velocity, salinity, and temperature and suspended sediment concentration. At one impoundment site and the control site, weather stations recorded wind speed and direction. This paper describes and discusses the results.

Dingler, John R.

1993-01-01

235

Ground-water level data for North Carolina, 1987  

Science.gov (United States)

Continuous and periodic measurements in 54 key wells and water-level measurements emplaced in Coastal Plain aquifers across North Carolina in 193 supplemental wells are presented in this report. Hydrographs of selected wells show changes in ground-water storage in the State. The water table in the shallow aquifers was higher throughout most of the State in 1987 than in 1986, indicating that rain had recharged these aquifers sufficiently to replenish the deficit in ground water storage that accumulated in the western and central parts of the State during 1986. Water levels in the heavily pumped Coastal Plain aquifers show a general downward trend for the year, indicating ground water is being withdrawn from aquifer storage. Record low water levels were measured in 4 of 13 wells in the Castle Hayne aquifer; the greatest decline measured during 1987 was 0.3 ft. Water levels in wells in the Peedee, Black Creek, upper Cape Fear, and lower Cape Fear aquifers generally show downward trends. Record low water levels were measured in 4 of 8 wells in the Peedee aquifer; the maximum decline measured during 1987 was 1.5 ft. All wells in the Black Creek, upper Cape Fear, and lower Cape Fear aquifers had record low water levels for 1987, with maximum measured declines in 1987 of 8.6, 3.1, and 3.1 ft., respectively. Record high water levels were measured in two wells, one each in the Castle Hayne and Peedee aquifers. Potentiometric surface maps show the effects of major centers of pumping for the Castle Hayne, Black Creek, and lower Cape Fear aquifers of the Coastal Plain.

Coble, Ronald W.; Strickland, A.G.; Bailey, M. Carl

1989-01-01

236

Maximum permissible level of radio activity in drinking water  

Directory of Open Access Journals (Sweden)

Full Text Available The possible for contamination of water by radio activity due to radioisotopes which can be ingested by drinking contaminated water have been discussed. The factors on which hazards associated with radioactive contamination have been dealt with in detail. The maximum permissible level of radioisotopes in water as laid down by the I.R.P.C., U.K. and U.S.A. are compared. To meet emergencies certain emergency permissible levels of radioactivity have been suggested, giving the importance of these levels. Lastly, some precautionary measures for protection and methods for decontamination have been explained.

P. C. Gupta

2014-05-01

237

Carboxyhaemoglobin levels in water-pipe and cigarette smokers  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english Water-pipe smoking is growing in popularity, especially among young people, because of the social nature of the smoking session and the assumption that the effects are less harmful than those of cigarette smoking. It has however been shown that a single water-pipe smoking session produces a 24-hour [...] urinary cotinine level equivalent to smoking 10 cigarettes per day. AIM: We aimed to measure carboxyhaemoglobin (COHb) blood levels before and after water-pipe and cigarette smoking sessions. METHOD: Self-confessed smokers older than 18 years (N=30) volunteered to smoke a water-pipe or a cigarette and have their blood COHb levels measured under controlled conditions. RESULTS: Mean baseline COHb levels were 2.9% for the 15 cigarette smokers and 1.0% for the 15 water-pipe smokers. Levels increased by a mean of 481.7% in water-pipe smokers as opposed to 39.9% in cigarette smokers. CONCLUSION: The study demonstrated that water-pipe smokers had significantly higher increases in blood COHb levels thancigarette smokers during a single smoking session.

Ansa, Theron; Cedric, Schultz; James A, Ker; Nadia, Falzone.

2010-02-01

238

Modelling Water Level Influence on Habitat Choice and Food Availability for Zostera Feeding Brent Geese Branta bernicla in Non-Tidal Areas  

DEFF Research Database (Denmark)

Brent geese Branta bernicla spring fattening around Agero, Denmark, alternate between feeding on saltmarshes and submerged Zostera beds in Limfjorden. It appeared from field observations that these alternations depended on the water level in Limfjorden. A model was developed to assess the impact of water level fluctuations on the habitat use. A second model was developed to estimate the impact of water level on Zostera availability. The first model was successful in demonstrating that fluctuations in water levels had considerable influence on habitat use by the brent geese, i.e. they fed on Zostera at low water levels and on saltmarshes during high water levels, particularly so in early spring, and that the switch between habitats occurred within a narrow water level span of ca 30 cm. The second model demonstrated that the switch between habitats could be explained by lowered availability of Zostera as water levels increased. By combining the output from the two models, differences between years could partly be explained by differences in Zostera availability in the early spring period (21 March - 25 April), whereas a more complicated situation was detected later in spring (26 April - 31 May). The models presented may be considered as tools in investigations of habitat use and carrying capacity of seagrass beds in non-tidal areas, where birds' access to feeding areas regularly may be hindered by high water levels.

Clausen, P.

2000-01-01

239

A multi-source satellite data approach for modelling Lake Turkana water level: Calibration and validation using satellite altimetry data  

Science.gov (United States)

Lake Turkana is one of the largest desert lakes in the world and is characterized by high degrees of interand intra-annual fluctuations. The hydrology and water balance of this lake have not been well understood due to its remote location and unavailability of reliable ground truth datasets. Managing surface water resources is a great challenge in areas where in-situ data are either limited or unavailable. In this study, multi-source satellite-driven data such as satellite-based rainfall estimates, modelled runoff, evapotranspiration, and a digital elevation dataset were used to model Lake Turkana water levels from 1998 to 2009. Due to the unavailability of reliable lake level data, an approach is presented to calibrate and validate the water balance model of Lake Turkana using a composite lake level product of TOPEX/Poseidon, Jason-1, and ENVISAT satellite altimetry data. Model validation results showed that the satellitedriven water balance model can satisfactorily capture the patterns and seasonal variations of the Lake Turkana water level fluctuations with a Pearson's correlation coefficient of 0.90 and a Nash-Sutcliffe Coefficient of Efficiency (NSCE) of 0.80 during the validation period (2004-2009). Model error estimates were within 10% of the natural variability of the lake. Our analysis indicated that fluctuations in Lake Turkana water levels are mainly driven by lake inflows and over-the-lake evaporation. Over-the-lake rainfall contributes only up to 30% of lake evaporative demand. During the modelling time period, Lake Turkana showed seasonal variations of 1-2m. The lake level fluctuated in the range up to 4m between the years 1998-2009. This study demonstrated the usefulness of satellite altimetry data to calibrate and validate the satellite-driven hydrological model for Lake Turkana without using any in-situ data. Furthermore, for Lake Turkana, we identified and outlined opportunities and challenges of using a calibrated satellite-driven water balance model for (i) quantitative assessment of the impact of basin developmental activities on lake levels and for (ii) forecasting lake level changes and their impact on fisheries. From this study, we suggest that globally available satellite altimetry data provide a unique opportunity for calibration and validation of hydrologic models in ungauged basins. ?? Author(s) 2012.

Velpuri, N.M.; Senay, G.B.; Asante, K.O.

2012-01-01

240

A multi-source satellite data approach for modelling Lake Turkana water level: calibration and validation using satellite altimetry data  

Directory of Open Access Journals (Sweden)

Full Text Available Lake Turkana is one of the largest desert lakes in the world and is characterized by high degrees of inter- and intra-annual fluctuations. The hydrology and water balance of this lake have not been well understood due to its remote location and unavailability of reliable ground truth datasets. Managing surface water resources is a great challenge in areas where in-situ data are either limited or unavailable. In this study, multi-source satellite-driven data such as satellite-based rainfall estimates, modelled runoff, evapotranspiration, and a digital elevation dataset were used to model Lake Turkana water levels from 1998 to 2009. Due to the unavailability of reliable lake level data, an approach is presented to calibrate and validate the water balance model of Lake Turkana using a composite lake level product of TOPEX/Poseidon, Jason-1, and ENVISAT satellite altimetry data. Model validation results showed that the satellite-driven water balance model can satisfactorily capture the patterns and seasonal variations of the Lake Turkana water level fluctuations with a Pearson's correlation coefficient of 0.90 and a Nash-Sutcliffe Coefficient of Efficiency (NSCE of 0.80 during the validation period (2004–2009. Model error estimates were within 10% of the natural variability of the lake. Our analysis indicated that fluctuations in Lake Turkana water levels are mainly driven by lake inflows and over-the-lake evaporation. Over-the-lake rainfall contributes only up to 30% of lake evaporative demand. During the modelling time period, Lake Turkana showed seasonal variations of 1–2 m. The lake level fluctuated in the range up to 4 m between the years 1998–2009. This study demonstrated the usefulness of satellite altimetry data to calibrate and validate the satellite-driven hydrological model for Lake Turkana without using any in-situ data. Furthermore, for Lake Turkana, we identified and outlined opportunities and challenges of using a calibrated satellite-driven water balance model for (i quantitative assessment of the impact of basin developmental activities on lake levels and for (ii forecasting lake level changes and their impact on fisheries. From this study, we suggest that globally available satellite altimetry data provide a unique opportunity for calibration and validation of hydrologic models in ungauged basins.

N. M. Velpuri

2012-01-01

241

Stratigraphic study of beach features on the southwestern shore of Lake Michigan: new evidence of Holocene lake-level fluctuations. Environmental geology notes  

International Nuclear Information System (INIS)

Research conducted in the Chicago area over the past decade has resulted in detailed interpretation of changes. Stratigraphic studies, coupled with radiocarbon dating, indicate that conspicuous fluctuations of Lake Michigan have occurred during the past 2,000 years - a period previously recognized as one of relatively stable levels. Results of this study indicate a pattern of lake level changes not discernible in the 125-year historically recorded and measured changes; the historically recorded changes in lake level represent only part of a long-term, naturally fluctuating trend that in some cases may have exceeded the maxima and minima of the historically-recorded lake levels

242

Trace-level mercury removal from surface water  

Energy Technology Data Exchange (ETDEWEB)

Many sorbents have been developed for the removal of mercury and heavy metals from waters; however, most of the data published thus far do not address the removal of mercury to the target levels represented in this project. The application to which these sorbents are targeted for use is the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Sorbents with thiouronium, thiol, amine, sulfur, and proprietary functional groups were selected for these studies. Mercury was successfully removed from surface water via adsorption onto Ionac SR-4 and Mersorb resins to levels below the target goal of 12 ng/L in batch studies. A thiol-based resin performed the best, indicating that over 200,000 volumes of water could be treated with one volume of resin. The cost of the resin is approximately $0.24 per 1,000 gal of water.

Klasson, K.T.; Bostick, D.T.

1998-06-01

243

Trace-level mercury removal from surface water  

International Nuclear Information System (INIS)

Many sorbents have been developed for the removal of mercury and heavy metals from waters; however, most of the data published thus far do not address the removal of mercury to the target levels represented in this project. The application to which these sorbents are targeted for use is the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Sorbents with thiouronium, thiol, amine, sulfur, and proprietary functional groups were selected for these studies. Mercury was successfully removed from surface water via adsorption onto Ionac SR-4 and Mersorb resins to levels below the target goal of 12 ng/L in batch studies. A thiol-based resin performed the best, indicating that over 200,000 volumes of water could be treated with one volume of resin. The cost of the resin is approximately $0.24 per 1,000 gal of water

244

Ditch water levels manages for environmental aims: effects on field soil water regimes  

OpenAIRE

The effects of ditch water management regimes on water tables are examined for two test sites in England, Halvergate in the Broads and Southlake Moor in the Somerset Levels and Moors Environmentally Sensitive Areas. It is observed that in some fields the effects of water management are only poorly transferred from the ditch to the field centre, especially where the hydraulic conductivity of the subsoil is small. Where there are large variations in the ditch water levels, reflecting the influe...

Armstrong, A.; Rose, S.

1999-01-01

245

Fluctuation of TeV to EeV Energy Muons and Induced Muon Showers in Water  

CERN Document Server

By using the integral method in the muon propagation through water, we calculate the range fluctuation of high and ultra high energy muons. Many authors divide all radiative processes into two parts, namely, the continuous part and radiative part in their Monte Carlo simulation in order to consider the fluctuation in the both ranges and energies of the muons, while we treat all stochastic processes as exactly as possible, without the introduction of the continuous parts in all stochastic processes. The validity of our Monte Carlo method is checked by the corresponding analytical method which is methodologically independent on the Monte Carlo procedure. Accompanied cascade showers are generated by the direct electron pair production, bremsstrahlung and photo-nuclear interaction. These showers are calculated by the exact Monte Carlo Method in one dimensional way. We report survival probabilities, range distributions and examples of individual muon behavior.

Okumura, Y; Misaki, A

2010-01-01

246

Experience of water chemistry and radiation levels in Swedish BWRs  

International Nuclear Information System (INIS)

From the BWR operational experience in Sweden it has been found that the occupational radiation exposures have been comparatively low in an international comparison. One main reason for the favourable conditions is the good water chemistry performance. This paper deals at first with the design considerations of water chemistry and materials selection. Next, the experience of water chemistry and radiation levels are provided. Finally, some methods to further reduce the radiation sources are discussed. (author)

247

Scaling properties of pH fluctuations in coastal waters of the English Channel: pH as a turbulent active scalar  

Directory of Open Access Journals (Sweden)

Full Text Available We consider here pH and temperature fluctuations in marine waters, recorded at fixed points using high resolution automatic devices. We analyze time series coming from 4 monitoring stations located along French coast: one station is situated in the coastal area off Boulogne-sur-mer (Eastern English Channel and 3 stations in the Bay of Seine. All these pH time series reveal large fluctuations at all scales similar to turbulent temperature fluctuations. We compare the pH and temperature time series through Fourier spectral analysis methods: spectra, compensated spectra, cospectra. We find good scaling properties of pH fluctuations, with power spectral slopes close to 1.5 for marine stations and 1.2 for the estuarine station. These analyses show that pH fluctuations in marine waters are strongly influenced by turbulent hydrodynamical transport, and may be considered as a turbulent active scalar.

S. B. Zongo

2011-11-01

248

Radium-226 levels in Italian drinking waters and foods  

International Nuclear Information System (INIS)

Levels of 226Ra in Italian waters and foods were measured. Results were similar to those found in other countries, except for some mineral waters with 226Ra concentrations above 1 pCi/liter andup to 19 pCi/liter. No difinite correlation was found between the 226Ra concentrations measured and the high natural background radiation levels determined in central Italy in previous work

249

Typhoon and elevated radon level in a municipal water supply  

International Nuclear Information System (INIS)

The Municipal Water Supply at Hsinchu City is a water treatment plant using poly- aluminum chloride (PAC) for coagulation and then followed by precipitation and filtration. Its capacity is 70,000 m3/day. The raw water is drawn from the nearby river. Since the subject of interest is the radon level during typhoon season, the sampling period was from March to December 1999. Commercially available electret was used for water samples taken from the five ponds in the plant. This technique relies on the measurement of radon in air above a water sample enclosed in a sealed vessel. The concentration of airbone radon released from water was determined by means of the electret ion chamber. During the first sampling period there came two typhoons. One is called Magie during June 10-17, and the other called Sam during August 20-26. The first typhoon led to the radon level measured from the water samples as high as 705 Bq/m3, while the second caused even higher radon level as high as 772 Bq/m3. Similar results were obtained for the second sampling period after August till December 1999. For those measured without typhoon influence, the average radon was lower from the coagulation pond yet without coagulation process during March through August 1999. However, water samples taken from the pond after precipitation did not show similar results in radon level. (author)

250

Ecological changes and water level variation in Sélingué Reservoir (Mali)  

Science.gov (United States)

Sélingué is a monomictic reservoir in Mali (West Africa), featuring annual water level change up to 8 m. High waters occur from November, after the flood, while low waters occur from June, at the end of the dry season. Water level decrease is linked to environmental factors (marked hydrological pattern, both for flow and rains) and to human management of the dam (keeping high the water level of the Office du Niger Agriculture Area during the dry season and hydropower production during the hottest months of the year). To study the ecological impact of such water level variations, environmental and biological descriptors were studied on water sampled biweekly from November 2000 to November 2001 in a station representative of the north part of Sélingué. The water column is stratified from March to May, as a result of the cooling induced by NE trade winds. In such conditions, the hypolimnion is anoxic. During calm periods in the dry season, the hypolimnion can progressively increase in thickness; the metalimnion gets closer to the surface and in some cases, the epilimnion can vanish and fish mortality is then observed. But stratification can also act as a trap for nutrients in the hypolimnion, preventing the euphotic epilimnion to be re-alimented in dissolved P and N mineral components. This sink-phase is replaced by a spring-phase when the water column is not anymore stratified and when the water level is low enough to allow wind-induced resuspension and vertical mixing. Such nutrient enrichment of the euphotic layer is observed at the end of the dry season. As a consequence, phytoplankton blooms are observed. Finally, water level is also important for fisheries, since fishes are diluted in high water (i.e. more difficult to catch with the artisanal tools operated by the local fishermen) but are concentrated in low water (i.e. more easily over fished in the minor bed, where most fishes are sheltered at the end of the dry season). Wise rules of water level management could help to minimize these ecological consequences.

Arfi, R.

2003-04-01

251

The backend design of an environmental monitoring system upon real-time prediction of groundwater level fluctuation under the hillslope.  

Science.gov (United States)

The groundwater level represents a critical factor to evaluate hillside landslides. A monitoring system upon the real-time prediction platform with online analytical functions is important to forecast the groundwater level due to instantaneously monitored data when the heavy precipitation raises the groundwater level under the hillslope and causes instability. This study is to design the backend of an environmental monitoring system with efficient algorithms for machine learning and knowledge bank for the groundwater level fluctuation prediction. A Web-based platform upon the model-view controller-based architecture is established with technology of Web services and engineering data warehouse to support online analytical process and feedback risk assessment parameters for real-time prediction. The proposed system incorporates models of hydrological computation, machine learning, Web services, and online prediction to satisfy varieties of risk assessment requirements and approaches of hazard prevention. The rainfall data monitored from the potential landslide area at Lu-Shan, Nantou and Li-Shan, Taichung, in Taiwan, are applied to examine the system design. PMID:21409360

Lin, Hsueh-Chun; Hong, Yao-Ming; Kan, Yao-Chiang

2012-01-01

252

A Feasibility Study to Lower Steam Generator Low Water Level Trip Setpoint to Reduce Unnecessary Scram Frequency for KORI 3,4 Plant  

International Nuclear Information System (INIS)

The steam generator low water level trip setpoint of KORI NPP units 3 and 4(KNU 3 and 4), three-loop Westinghouse pressurized water reactor, is higher than that of OPR1000. In addition, steam generator downcomer water level in KNU 3 and 4 could fluctuate easily during a transient because of smaller downcomer water inventory, compared to the total water inventory in the steam generator. Due to these reasons, there is a higher possibility of unnecessary reactor trips caused by the steam generator low-low water level in KNU 3 and 4. Its operating history shows that most of reactor trips were caused by steam generator low-low level reactor trip signal. Such reactor trips, especially unnecessary ones, result in time and economic losses. In this paper, a feasibility study was performed to reduce unnecessary reactor trip by changing steam generator low-low water level reactor trip setpoint(SGLLRTS) for KNU 3 and 4

253

Hydroxyl radicals cause fluctuation in intracellular ferrous ion levels upon light exposure during photoreceptor cell death.  

Science.gov (United States)

Iron accumulation is a potential pathogenic event often seen in age-related macular degeneration (AMD) patients. In this study, we focused on the relationship between AMD pathology and concentrations of ferrous ion, which is a highly reactive oxygen generator in biological systems. Murine cone-cells-derived 661W cells were exposed to white florescence light at 2500 lx for 1, 3, 6, or 12 h. Levels of ferrous ions, reactive oxygen species (ROS), and hydroxyl radicals were detected by RhoNox-1, a novel fluorescent probe for the selective detection of ferrous ion, 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA), and 3'-p-(aminophenyl) fluorescein, respectively. Reduced glutathione, total iron levels and photoreceptor cell death were also measured. Two genes related to iron metabolism, transferrin receptor 1 (TfR1) and H ferritin (HFt), were quantified by RT-PCR. The effects of ferrous ion on cell death and hydroxyl radical production were determined by treatment with a ferrous ion chelating agent, 2,2'-bipyridyl. We found that the ferrous ion level decreased with light exposure in the short time frame, whereas it was upregulated during a 6-h light exposure. Total iron, ROS, cell death rate, and expression of TfR and HFt genes were significantly increased in a time-dependent manner in 661W cells exposed to light. Chelation with 2,2'-bipyridyl reduced the level of hydroxyl radicals and protected against light-induced cell death. These results suggest that light exposure decreases ferrous ion levels and enhances iron uptake in photoreceptor cells. Ferrous ion may be involved in light-induced photoreceptor cell death through production of hydroxyl radicals. PMID:25447561

Imamura, Tomoyo; Hirayama, Tasuku; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Nagasawa, Hideko; Hara, Hideaki

2014-12-01

254

Current-induced two-level fluctuations in pseudo spin-valves (Co/Cu/Co) nanostructures  

CERN Document Server

Two-level fluctuations of the magnetization state of pseudo spin-valve pillars Co(10 nm)/Cu(10 nm)/Co(30 nm) embedded in electrodeposited nanowires (~40 nm in diameter, 6000 nm in length) are triggered by spin-polarized currents of 10^7 A/cm^2 at room temperature. The statistical properties of the relaxation times between transitions from parallel to antiparallel magnetization states (and vice versa) reveal two effects with qualitatively different dependences on current intensity. The current appears to have the effect of a bias field, evaluated experimentally as the counteracting applied field that equalizes the mean relaxation times. When the energy profile is a symmetric double well, the effect of a current density of 10^7 A/cm^2 is to decrease the effective energy barrier by 1000 K. The bias field changes sign when the current polarity is reversed. The barrier is lowered, irrespective of the sign of the current.

Fabian, A C; Guisan, S S; Hoffer, X; Dubey, M; Gravier, L; Ansermet, J P; Wegrowe, J E

2003-01-01

255

Comparison of genetic programming with neuro-fuzzy systems for predicting short-term water table depth fluctuations  

Science.gov (United States)

This paper investigates the ability of genetic programming (GP) and adaptive neuro-fuzzy inference system (ANFIS) techniques for groundwater depth forecasting. Five different GP and ANFIS models comprising various combinations of water table depth values from two stations, Bondville and Perry, are developed to forecast one-, two- and three-day ahead water table depths. The root mean square errors ( RMSE), scatter index ( SI), Variance account for ( VAF) and coefficient of determination ( R2) statistics are used for evaluating the accuracy of models. Based on the comparisons, it was found that the GP and ANFIS models could be employed successfully in forecasting water table depth fluctuations. However, GP is superior to ANFIS in giving explicit expressions for the problem.

Shiri, Jalal; Ki?i, Özgur

2011-10-01

256

Determination of Heavy Metal Levels in Various Industrial Waste Waters  

Directory of Open Access Journals (Sweden)

Full Text Available Important part of the environmetal pollution consists of waste water and water pollution. The water polluted by anthropogenical, industrial, and agricultural originated sources are defined as waste waters which are the main pollution sources for reservoirs, rivers, lakes, and seas. In this work, waste waters of leather, textile, automotive side, and metal plating industries were used to determine the levels of Cu, Zn, Cr, Pb and Ni by using Flame Atomic Absorption Spectrometer. As a result, highest mean levels of copper in supernatants of plating and textile industries were observed as 377,18 ng ml-1, respectively 103 ng ml-1 lead and 963,6 ng ml-1 nickel in plating industry, 1068,2 ng ml-1 zinc and 14557,1 ng ml-1 chromium in plating and leather industries were determined.

Mustafa ?ahin Dündar

2012-06-01

257

Sea-level fluctuations and coastal evolution in the state of Rio de Janeiro, southeastern Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O presente trabalho tem como objetivo investigar as variações do nível relativo do mar e a evolução costeira durante o Holoceno no litoral do Estado do Rio de Janeiro, com base em indicadores geológicos e biológicos. Realizou-se levantamento altimétrico, execução de sondagens e datações ao 14C na pl [...] anície costeira e em afloramentos de rochas de praia. A partir dos dados obtidos, construiu-se uma curva do nível relativo do mar para o Holoceno. Pela primeira vez na costa brasileira foi identificado um recorde negativo do nível relativo do mar, envolvendo a transição final do Pleistoceno e início do Holoceno. Após a transição, iniciou-se um processo relativamente rápido de subida do nível do mar. Há aproximadamente 8.500 anos cal A.P., o nível marinho, encontrava-se a - 0.5 m abaixo do nível atual. O “zero” (nível médio atual) foi ultrapassado pela primeira vez no Holoceno há cerca de 7.500 anos A.P. Entre 5.500 - 4.500 cal anos A.P, o nível relativo do mar atingiu o primeiro máximo holocênico com altura máxima de +2.50 m acima do atual. A descida do nível relativo do mar subseqüente ao máximo transgressivo, levou à construção de terraços marinhos, resultando na progradação da linha de costa até o presente. A maioria dos resultados corroboram dados já obtidos em outros segmentos da costa atlântica da América do Sul. Resultados aqui apresentados são consistentes com pesquisas anteriores e ajudam refinar o registro do nível relativo do mar Holoceno na costa brasileira. Abstract in english The present paper aims to investigate the relative sea-level and the coastal evolution during the Holocene in the Rio de Janeiro coastline, based on geological and biological indicators. Using topographic survey, excavation and coring, and 14C dating of these coastal deposits and beachrocks outcrops [...] , we have reconstructed a sea-level curve for the Holocene. For the first time on the Brazilian coast it was identified a negative record of relative sea-level during Late Pleistocene and Early Holocene transition. After the transition, a relatively rapid increase of sea-level began. At approximately at 8500 cal yr BP, the sea-level was 0.5 m below the current level, was overtaken for the first time in the Holocene, at approximately 7500 cal yr BP. The maximum level of +2.5 m was reached between 4770 and 4490 cal yr BP. At the point of maximum transgression, the sea-level began a general behavior of lowering until the present. These results confirm other data already obtained elsewhere along the Atlantic coast of South America. The results of this study are consistent with previous researches and they help to refine the Holocene sea-level record along the Brazilian coast.

JOÃO WAGNER A., CASTRO; KENITIRO, SUGUIO; JOSÉ C.S., SEOANE; ALINE M. DA, CUNHA; FABIO F., DIAS.

2014-06-01

258

Performance of broilers submitted to high CO2 levels during incubation combined with temperature fluctuations at late post-hatch  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Incubation represents around 1/3 of the life cycle of broilers of modern strains; therefore, the appropriate management of this period is crucial to ensure the quality of the neonate. An experiment evaluated the effect of carbon dioxide concentrations during incubation on the live performance, heart [...] morphology, and differential leukocyte count in the blood of broilers submitted to fluctuating temperatures between 35 and 42 days of age. In total, 2,520 fertile eggs were distributed according to a completely randomized design with four CO2 concentrations (4,000; 6,000; 8,000 and 10,000 ppm) during the first ten days of incubation, after which all eggs were incubated at the same CO2 level (4,000 ppm). After hatching, male chicks were placed in the experimental broiler houses, and at 35 days of age, 25 birds from each level of CO2 were separated and placed in cages to study the effect of cyclic temperature variations up to 42 days of age on their live performance, heterophil:lymphocyte ratio, and heart morphology. At 42 days of age, blood was collected for hematology and two birds per replicate were sacrificed and evaluated for ascites score and heart and liver relative weights. Heart morphology was assessed by analyzing digital images. In this experiment, hypercapnia during incubation and fluctuating temperatures during the growout did not affect mortality, ascites score, heart and liver relative weights, or heart characteristics (p>0.05). However, heterophill:lymphocyte ratio increased (p

JIM, Fernandes; C, Bortoluzzi; AFG, Esser; JP, Contini; PB, Stokler; D, Faust.

2014-09-01

259

Monitoring of water level inside reactor pressure vessel  

International Nuclear Information System (INIS)

Up to the TMI accident the water level inside the pressurizer was used to monitor the water inventory inside the primary cooling system of pressurized water reactors. The TMI accident showed that this was not a reliable measurement for the reactor coolant inventory inside the reactor pressure vessel. For this reason there was a demand for a measurement of the water level inside the RVP, independent from the existing one inside the pressurizer and with a diverse measuring method. For WWER reactors a new level measurement system was developed to monitor the water level inside the reactor pressure vessel by means of the KNITU, resp. KITU level probe which meet all the mentioned engineered safeguards and geometric and constructive requirements. First backfitting s of the new level measurement system in the WWER s 440 in Bohunice V1 (Slovakia), unit 1 (1998) and unit 2 (2000), Novovoronezh (Russia), unit 4 (1999) and Kola (Russia), unit 1 and unit 2 (1999) show very good operational results. (Authors)

260

WATER-LEVEL MONITOR FOR BOREWELL AND WATER TANK BASED ON GSM  

Directory of Open Access Journals (Sweden)

Full Text Available Now a days, home automation & remote control and monitoring systems have seen a rapid growth in terms of technology. Apparently there is no early warning system to monitor the tank water level and bore well water level when it has reached the critical level. In this paper we have provided water level monitoring in the tank as well as in the bore well. If the water level in a bore well drops below the threshold level for pumping its pump motor may get air locked or more burn out due to dry running. It is awkward for farmers to walk all the way to their fields at night just to switch the pump motor off. Besides, he may never get to identify the problem. This problem can be solved by using this GSM based system that will automatically make a call to the user mobile phone, when the water Level in the bore well drops threshold below or rises to the threshold level for pumping. The user can also remotely switch on or off the pump motor by sending a SMS from his mobile phone. The system is simple, reliable, portable and affordable. We proposed the work in which, Whenever water level in the tankdrops below the required level the system try to fill the tank by switching on the bore well motor to pump the water into the tank It is must to have enough water in the bore well to avoid the formation of air gap or empty running of bore well motor. High precision water level sensor is used to identify the reference water level to activate and deactivate the motor and system properly by interfacing the sensor devices into the well definedembedded system.

R.Ramani

2012-10-01

261

Exact Analysis of Level-Crossing Statistics for ( d+1)-Dimensional Fluctuating Surfaces  

Science.gov (United States)

We carry out an exact analysis of the average frequency ?+ ? xi in the direction x i of positiveslope crossing of a given level ? such that, h( x, t) -bar{h} = ?, of growing surfaces in spatial dimension d. Here, h( x, t) is the surface height at time t, and bar{h} is its mean value. We analyze the problem when the surface growth dynamics is governed by the Kardar-Parisi-Zhang (KPZ) equation without surface tension, in the time regime prior to appearance of cusp singularities (sharp valleys), as well as in the random deposition (RD) model. The total number N + of such level-crossings with positive slope in all the directions is then shown to scale with time as t d/2 for both the KPZ equation and the RD model.

Bahraminasab, A.; Movahed, M. Sadegh; Nasiri, S. D.; Masoudi, A. A.; Sahimi, Muhammad

2006-09-01

262

Great Lakes Water Levels Bounce Back After Record Lows  

Science.gov (United States)

Water levels in the Great Lakes have rebounded dramatically from historic lows in December 2012 and January 2013, though the levels still remain lower than average in some of the lakes, scientists with the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Army Corps of Engineers said during a 20 November briefing. The low lake levels had hampered shipping and other commercial and recreational uses of the waterways.

Showstack, Randy

2013-12-01

263

Environmental factors related to water level regulation - a comparative study in northern Finland  

International Nuclear Information System (INIS)

The environmental conditions of the littoral zone were studied in the regulated Lake Ontojaervi and the unregulated Lake Lentua in northern Finland. The general aims of the study were to analyse the environmental factors related to water level regulation in the littoral zone and to produce information for assessing the effects of hydroelectric development in northern lakes. The study was basically carried out by comparing the littoral environments of the two study lakes. The most visible effects of water level regulation were related to the raised water level, which yielded erosion of sandy shores at the beginning of the regulation. Another effect of lake regulation was the altered fluctuation of the water level, which led to bottom instability and increased the size of the frozen and ice penetration zones. The effect of ice penetration was also easy to recognize on the shores of Lake Ontojaervi, where the surface sediment was frozen to a greater depth and across wider areas than in Lake Lentua. Below the freezing zone, the ice just pressed down on the sediment. The shores of Lake Ontojaervi were steeper than those of Lake Lentua, which affected the distribution of bottom types, with sandy bottoms being more common in Lake Lentua than in Lake Ontojaervi. The factors related to site exposure included effective fetch and the shape of the shoreline. The sedimentation level correlated only with the slope and was not predicted by the fetch or shape. The vertical reduction he fetch or shape. The vertical reduction of light was estimated on the basis of water colour. The main environmental factors from the two lakes were used in a discriminant analysis to predict the bottom type distribution of the littoral (r2 = 0.41). (orig.) 66 refs

264

Elimination of two level fluctuators in superconducting quantum bits by an epitaxial tunnel barrier  

International Nuclear Information System (INIS)

Quantum computing based on Josephson junction technology is considered promising due to its scalable architecture. However, decoherence is a major obstacle. Here, we report evidence for improved Josephson quantum bits (qubits) using a single-crystal Al2O3 tunnel barrier. We have found an ?80% reduction in the density of the spectral splittings that indicate the existence of two-level fluctators (TLFs) in amorphous tunnel barriers. The residual ?20% TLFs can be attributed to interfacial effects that may be further reduced by different electrode materials. These results show that decoherence sources in the tunnel barrier of Josephson qubits can be identified and eliminated

265

Ground-water discharge determined from measurements of evapotranspiration, other available hydrologic components, and shallow water-level changes, Oasis Valley, Nye County, Nevada  

Science.gov (United States)

Oasis Valley is an area of natural ground-water discharge within the Death Valley regional ground-water flow system of southern Nevada and adjacent California. Ground water discharging at Oasis Valley is replenished from inflow derived from an extensive recharge area that includes the northwestern part of the Nevada Test Site (NTS). Because nuclear testing has introduced radionuclides into the subsurface of the NTS, the U.S. Department of Energy currently is investigating the potential transport of these radionuclides by ground water flow. To better evaluate any potential risk associated with these test-generated contaminants, a number of studies were undertaken to accurately quantify discharge from areas downgradient in the regional ground-water flow system from the NTS. This report refines the estimate of ground-water discharge from Oasis Valley. Ground-water discharge from Oasis Valley was estimated by quantifying evapotranspiration (ET), estimating subsurface outflow, and compiling ground-water withdrawal data. ET was quantified by identifying areas of ongoing ground-water ET, delineating areas of ET defined on the basis of similarities in vegetation and soil-moisture conditions, and computing ET rates for each of the delineated areas. A classification technique using spectral-reflectance characteristics determined from satellite imagery acquired in 1992 identified eight unique areas of ground-water ET. These areas encompass about 3,426 acres of sparsely to densely vegetated grassland, shrubland, wetland, and open water. Annual ET rates in Oasis Valley were computed with energy-budget methods using micrometeorological data collected at five sites. ET rates range from 0.6 foot per year in a sparse, dry saltgrass environment to 3.1 feet per year in dense meadow vegetation. Mean annual ET from Oasis Valley is estimated to be about 7,800 acre-feet. Mean annual ground-water discharge by ET from Oasis Valley, determined by removing the annual local precipitation component of 0.5 foot, is estimated to be about 6,000 acre-feet. Annual subsurface outflow from Oasis Valley into the Amargosa Desert is estimated to be between 30 and 130 acre-feet. Estimates of total annual ground-water withdrawal from Oasis Valley by municipal and non-municipal users in 1996 and 1999 are 440 acre-feet and 210 acre-feet, respectively. Based on these values, natural annual ground-water discharge from Oasis Valley is about 6,100 acre-feet. Total annual discharge was 6,500 acre-ft in 1996 and 6,300 acre-ft in 1999. This quantity of natural ground-water discharge from Oasis Valley exceeds the previous estimate made in 1962 by a factor of about 2.5. Water levels were measured in Oasis Valley to gain additional insight into the ET process. In shallow wells, water levels showed annual fluctuations as large as 7 feet and daily fluctuations as large as 0.2 foot. These fluctuations may be attributed to water loss associated with evapotranspiration. In shallow wells affected by ET, annual minimum depths to water generally occurred in winter or early spring shortly after daily ET reached minimum rates. Annual maximum depths to water generally occurred in late summer or fall shortly after daily ET reached maximum rates. The magnitude of daily water-level fluctuations generally increased as ET increased and decreased as depth to water increased.

Reiner, S.R.; Laczniak, R.J.; DeMeo, G.A.; Smith, J.L.; Elliott, P.E.; Nylund, W.E.; Fridrich, C.J.

2002-01-01

266

An Indirect Adaptive Controller to Regulate UTSG Water Level in Pressurized Water Nuclear Reactor  

OpenAIRE

Stabilizing water level of the Steam Generator (SG) in nuclear power plant is a very important problem since its parameters vary with operating conditions and dynamics of the system is very different according to the power levels and changes as time goes on. Therefore, it is an intractable as well as challenging task to improve the water level control system of the SG. In this study, a new framework for building an adaptive Minimum Variance controller for stabilizing water-level of SG is prop...

Djamel Boukhetala; Touati Sai; Khaled Halbaoui; Feres Boudjema

2012-01-01

267

Dynamics of a Landau-Zener non-dissipative system with fluctuating energy levels  

Science.gov (United States)

This paper considers a Landau-Zener (two-level) system influenced by a three-dimensional Gaussian and non-Gaussian coloured noise and finds a general form of the time dependent diabatic quantum bit (qubit) flip transition probabilities in the fast, intermediate and slow noise limits. The qubit flip probability is observed to mimic (for low-frequencies noise) that of the standard LZ problem. The qubit flip probability is also observed to be the measure of quantum coherence of states. The transition probability is observed to be tailored by non-Gaussian low-frequency noise and otherwise by Gaussian low-frequency coloured noise. Intermediate and fast noise limits are observed to alter the memory of the system in time and found to improve and control quantum information processing.

Fai, L. C.; Diffo, J. T.; Ateuafack, M. E.; Tchoffo, M.; Fouokeng, G. C.

2014-12-01

268

Daily water level by ENVISAT altimetry of the Amazon River  

Science.gov (United States)

Radar Altimetry is a remote sensing technique applied in order to obtain the level of water of the hydrological processes, mostly in remote regions such as in the Amazon basin. However, the altimetry satellites have a limitation in their temporal resolution, which in the case of ENVISAT is 35 days, which prevents the study of short-term hydrological events alert of floods and droughts and etc. Thus, a method of obtaining altimetric daily time series water level, based on a linear model of interpolation by optimization with multi-objective criteria was applied, using data from in situ on pluvial stations, along the Amazon River. The altimetry data validation show accurate results with a RMS of 11 cm, while the estimates carried out by the model obtained 63% of altimetric daily time series water level data with RMS less than 40 cm, thus allowing the use of altimetry data daily at various hydrological studies, hydrodynamic modeling and monitoring of extreme events.

Sousa, A. C.; Pereira, P.; Silva, J. S.; Calmant, S.; Seyler, F.

2013-05-01

269

Analysis of the cross-correlation between seismicity and water level in the Aswan area (Egypt) from 1982 to 2010  

Science.gov (United States)

In this study the correlation between the monthly fluctuations of the water level of the Aswan High Dam and monthly number of earthquakes from 1982 to 2010, which occurred in the surrounding area, was investigated. Our findings reveal that significant correlation is present during the period 1982-1993 between water level and shallow seismicity (depth less than 15 km). The deep seismicity (depth larger than 15 km) is significantly correlated with the water level between January and April 1989. The time lag of the significant maximal cross-correlation varies from 2-8~months for the shallow seismicity, while it is around 7-8 months for the deep seismicity. These values of the time lags could be in favour of the presence of two distinct triggering mechanisms: one due to pore pressure diffusion and the other due to fracture compaction (undrained response).

Telesca, L.; ElShafey Fat ElBary, R.; El-Ela Amin Mohamed, A.; ElGabry, M.

2012-07-01

270

Analysis of the cross-correlation between seismicity and water level in the Aswan area (Egypt from 1982 to 2010  

Directory of Open Access Journals (Sweden)

Full Text Available In this study the correlation between the monthly fluctuations of the water level of the Aswan High Dam and monthly number of earthquakes from 1982 to 2010, which occurred in the surrounding area, was investigated. Our findings reveal that significant correlation is present during the period 1982–1993 between water level and shallow seismicity (depth less than 15 km. The deep seismicity (depth larger than 15 km is significantly correlated with the water level between January and April 1989. The time lag of the significant maximal cross-correlation varies from 2–8~months for the shallow seismicity, while it is around 7–8 months for the deep seismicity. These values of the time lags could be in favour of the presence of two distinct triggering mechanisms: one due to pore pressure diffusion and the other due to fracture compaction (undrained response.

L. Telesca

2012-07-01

271

Geological events and Pliocene climate fluctuations explain the phylogeographical pattern of the cold water fish Rhynchocypris oxycephalus (Cypriniformes: Cyprinidae) in China.  

Science.gov (United States)

Background Rhynchocypris oxycephalus is a cold water fish with a wide geographic distribution including the relatively warm temperate regions of southern China. It also occurs in second- and third-step geomorphic areas in China. Previous studies have postulated that high-altitude populations of R. oxycephalus in southern China are Quaternary glacial relics. In this study, we used the mitochondrial gene Cytb and the nuclear gene RAG2 to investigate the species phylogeographical patterns and to test two biogeographic hypotheses: (1) that divergence between lineages supports the three-step model and (2) climatic fluctuations during the Quaternary resulted in the present distribution in southern China.ResultsPhylogenetic analysis detected three major matrilines (A, B, and C); with matrilines B and C being further subdivided into two submatrilines. Based on genetic distances and morphological differences, matriline A potentially represents a cryptic subspecies. The geographic division between matrilines B and C coincided with the division of the second and third geomorphic steps in China, suggesting a historical vicariance event. Pliocene climatic fluctuations might have facilitated the southwards dispersal of R. oxycephalus in matriline C, with the subsequent warming resulting in its split into submatrilines C1 and C2, leaving submatriline C2 as a relic in southern China.ConclusionsOur study demonstrates that geological events (three steps orogenesis) and climate fluctuations during the Pliocene were important factors in shaping phylogeographical patterns in R. oxycephalus. Notably, no genetic diversity was detected in several populations, all of which possessed unique genotypes. This indicates the uniqueness of local populations and calls for a special conservation plan for the whole species at the population level. PMID:25344323

Yu, Dan; Chen, Ming; Tang, Qiongying; Li, Xiaojuan; Liu, Huanzhang

2014-10-25

272

Wireless Automatic Water Level Control using Radio Frequency Communication  

OpenAIRE

Water scarcity is the serious issue in major cities. It is a common problem which is faced by every house owner, that when his tank is empty he has to switch on the motor and switch the motor off when it is full. Due to the busy life it is common that the tank usually overflows without notice. One has to keep on observing his tank water level to switch off the motor once it is switched on. And sometimes this also can happen that the motor coil burns because of absence of water in the sump. So...

Muktha Shankari, K.; Jyothi, K.; Manu, E. O.; Naveen, I. P.; HARSHA HERLE

2013-01-01

273

Water Quality and pH Levels in Aquatic Ecosystems  

Science.gov (United States)

In this fun and in depth hands-on experiment, learners test various liquid samples (distilled water, lemon juice, vinegar, and baking soda mixed with water) to determine their pH levels and identify each sample as either acid, base or neutral chemical. Then, over the course of several weeks, learners perform a number of tests and observe the affects of pH level on plants. The wrap up section of this activity discusses acid rain and its dramatic impact on aquatic animals, and tips for going further.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

274

Statistical characterization of fluctuations of a laser beam transmitted through a random air-water interface: new results from a laboratory experiment  

Science.gov (United States)

New results for characterizing laser intensity fluctuation statistics of a laser beam transmitted through a random air-water interface relevant to underwater communications are presented. A laboratory watertank experiment is described to investigate the beam wandering effects of the transmitted beam. Preliminary results from the experiment provide information about histograms of the probability density functions of intensity fluctuations for different wind speeds measured by a CMOS camera for the transmitted beam. Angular displacements of the centroids of the fluctuating laser beam generates the beam wander effects. This research develops a probabilistic model for optical propagation at the random air-water interface for a transmission case under different wind speed conditions. Preliminary results for bit-error-rate (BER) estimates as a function of fade margin for an on-off keying (OOK) optical communication through the air-water interface are presented for a communication system where a random air-water interface is a part of the communication channel.

Majumdar, Arun K.; Land, Phillip; Siegenthaler, John

2014-10-01

275

Measurement of water potential in low-level waste management  

International Nuclear Information System (INIS)

The measurement of soil water is important to the shallow land burial of low-level waste. Soil water flow is the principle mechanism of radionuclide transport, allows the establishment of stabilizing vegetation and also governs the dissolution and release rates of the waste. This report focuses on the measurement of soil water potential and provides an evaluation of several field instruments that are available for use to monitor waste burial sites located in arid region soils. The theoretical concept of water potential is introduced and its relationship to water content and soil water flow is discussed. Next, four major areas of soils research are presented in terms of their dependence on the water potential concept. There are four basic types of sensors used to measure soil water potential. These are: (1) tensiometers; (2) soil psychrometers; (3) electrical resistance blocks; and (4) heat dissipation probes. Tensiometers are designed to measure the soil water potential directly by measuring the soil water pressure. Monitoring efforts at burial sites require measurements of soil water over long time periods. They also require measurements at key locations such as waste-soil interfaces and within any barrier system installed. Electrical resistance blocks are well suited for these types of measurements. The measurement of soil water potential can be a difficult task. There are several sensors commercially available; however, each has its own limitations. It is important to carefully select the appropriate sensor for the job. The accuracy, range, calibration, and stability of the sensor must be carefully considered. This study suggests that for waste management activities, the choice of sensor will be the tensiometer for precise soil characterization studies and the electrical resistance block for long term monitoring programs

276

Application of the water table fluctuation method for estimating evapotranspiration at two phreatophyte-dominated sites under hyper-arid environments  

Science.gov (United States)

Shallow groundwater is primarily discharged via evapotranspiration (ETg) in arid and semi-arid riparian systems; however, the quantification of ETg remains a challenge in regional water resource assessments of such systems. In this study, the diagnostic indicators of groundwater evapotranspiration processes and the principles of applying the water table fluctuation (WTF) method to estimate ETg based on seasonal groundwater level changes were presented. These techniques were then used to investigate groundwater evapotranspiration processes at two sites dominated by phreatophytes (Tamarix ramosissima and Populus euphratica) within hyper-arid desert environments in northwestern China for the period 2010-2012. The results indicate that steady declines in the water table, which are commonly attributed to groundwater evapotranspiration, occurred at both sites during the growing season. Based on the proposed WTF method, the estimated ETg was 0.63-0.73 mm/d at the Tamarix ramosissima site and 1.89-2.33 mm/d at the Populus euphratica site during the summer months (June-August). Numerical simulations using a one-dimensional root water uptake model indicate that the seasonal variations in ETg at both sites were primarily dependent on the potential evaporation rates. Comparisons with previous studies on plant transpiration at similar sites in this area show that these results are reasonable. It is apparent that the WTF method can provide a simple and relatively inexpensive method of estimating ETg on a large scale in arid/semi-arid regions. However, there are significant uncertainties associated with time-dependent lateral flow rates, which creates a challenge when applying this method. In addition, the selection of calculation periods that show steady declines in the groundwater level can be somewhat subjective. To enhance the performance of the WTF method based on seasonal water table declines, further research on the estimation of lateral flow rates should be performed using an effective network of groundwater monitoring.

Wang, Ping; Grinevsky, Sergey O.; Pozdniakov, Sergey P.; Yu, Jingjie; Dautova, Dina S.; Min, Leilei; Du, Chaoyang; Zhang, Yichi

2014-11-01

277

Ensemble approach for projections of return periods of extreme water levels in Estonian waters  

Science.gov (United States)

The contribution of various drivers to the water level in the eastern Baltic Sea and the presence of outliers in the time series of observed and hindcast water level lead to large spreading of projections of future extreme water levels. We explore the options for using an ensemble of projections to more reliably evaluate return periods of extreme water levels. An example of such an ensemble is constructed by means of fitting several sets of block maxima (annual maxima and stormy season maxima) with a Generalised Extreme Value, Gumbel and Weibull distribution. The ensemble involves projections based on two data sets (resolution of 6 h and 1 h) hindcast by the Rossby Centre Ocean model (RCO; Swedish Meteorological and Hydrological Institute) and observed data from four representative sites along the Estonian coast. The observed data are transferred into the grid cells of the RCO model using the HIROMB model and a linear regression. For coastal segments where the observations represent the offshore water level well, the overall appearance of the ensembles signals that the errors of single projections are randomly distributed and that the median of the ensemble provides a sensible projection. For locations where the observed water level involves local effects (e.g. wave set-up) the block maxima are split into clearly separated populations. The resulting ensemble consists of two distinct clusters, the difference between which can be interpreted as a measure of the impact of local features on the water level observations.

Eelsalu, Maris; Soomere, Tarmo; Pindsoo, Katri; Lagemaa, Priidik

2014-12-01

278

AUTOMATED WATER LEVEL MEASUREMENTS IN SMALL-DIAMETER AQUIFER TUBES  

Energy Technology Data Exchange (ETDEWEB)

Groundwater contaminated with hexavalent chromium, strontium-90, and uranium discharges into the Columbia River along approximately 16 km (10 mi) of the shoreline. Various treatment systems have and will continue to be implemented to eliminate the impact of Hanford Site contamination to the river. To optimize the various remediation strategies, it is important to understand interactions between groundwater and the surface water of the Columbia River. An automated system to record water levels in aquifer sampling tubes installed in the hyporheic zone was designed and tested to (1) gain a more complete understanding of groundwater/river water interactions based on gaining and losing conditions ofthe Columbia River, (2) record and interpret data for consistent and defensible groundwater/surface water conceptual models that may be used to better predict subsurface contaminant fate and transport, and (3) evaluate the hydrodynamic influence of extraction wells in an expanded pump-and-treat system to optimize the treatment system. A system to measure water levels in small-diameter aquifer tubes was designed and tested in the laboratory and field. The system was configured to allow manual measurements to periodically calibrate the instrument and to permit aquifer tube sampling without removing the transducer tube. Manual measurements were collected with an e-tape designed and fabricated especially for this test. Results indicate that the transducer system accurately records groundwater levels in aquifer tubes. These data are being used to refine the conceptual and numeric models to better understand interactions in the hyporheic zone of the Columbia River and the adjacent river water and groundwater, and changes in hydrochemistry relative to groundwater flux as river water recharges the aquifer and then drains back out in response to changes in the river level.

PETERSEN SW; EDRINGTON RS; MAHOOD RO; VANMIDDLESWORTH PE

2011-01-14

279

Politics of innovation in multi-level water governance systems  

Science.gov (United States)

Innovations are being proposed in many countries in order to support change towards more sustainable and water secure futures. However, the extent to which they can be implemented is subject to complex politics and powerful coalitions across multi-level governance systems and scales of interest. Exactly how innovation uptake can be best facilitated or blocked in these complex systems is thus a matter of important practical and research interest in water cycle management. From intervention research studies in Australia, China and Bulgaria, this paper seeks to describe and analyse the behind-the-scenes struggles and coalition-building that occurs between water utility providers, private companies, experts, communities and all levels of government in an effort to support or block specific innovations. The research findings suggest that in order to ensure successful passage of the proposed innovations, champions for it are required from at least two administrative levels, including one with innovation implementation capacity, as part of a larger supportive coalition. Higher governance levels can play an important enabling role in facilitating the passage of certain types of innovations that may be in competition with currently entrenched systems of water management. Due to a range of natural biases, experts on certain innovations and disciplines may form part of supporting or blocking coalitions but their evaluations of worth for water system sustainability and security are likely to be subject to competing claims based on different values and expertise, so may not necessarily be of use in resolving questions of 'best courses of action'. This remains a political values-based decision to be negotiated through the receiving multi-level water governance system.

Daniell, Katherine A.; Coombes, Peter J.; White, Ian

2014-11-01

280

Fluctuations of the Caspian Sea level as an indicator of global climatic changes - using data from radiocarbon dating of sediments  

International Nuclear Information System (INIS)

Because of the large area of the basin water, the level of the Caspian Sea reflects the global change of climate of the Northern hemisphere. In order to reconstruct the paleoclimatic situation, samples were taken from ancient salt marshes, depressions and bars which form when the sea level has fallen significantly. Mollusc shells, peat, carbonates and organic matter were used for 14C dating. The data obtained demonstrate the relationship between the sea level and climatic changes. During cooling the sea level rises and vice versa. This relates to the long-period (13,000 y) as well as to the short-period (2,000-2,500 y) and to secular changes of the climate. (author)

281

Calibration of Nitrate Leaching and Water Table Fluctuation in Paddy Rice Field by DRAINMOD-N Software  

OpenAIRE

Fertilizers in agriculture are potential sources of environmental pollution, especially in ground water quality and soil resources. Studying factors effective in water and nutrient transport through soil profile is helpful for nutrient management to minimize adverse impacts on environment and nitrate leaching below the root zone. In this study, the ground water level and nitrate leaching transportation below the root zone were measured in a paddy rice field and the data were simulated with th...

Zare Abyaneh, H.

2011-01-01

282

Experimental detection of radiative energy signal from a supercharged marine boiler and simulation on its application in control of drum water level  

International Nuclear Information System (INIS)

This paper describes a study on the application of a flame detecting system installed in a marine supercharged boiler. Flame images captured from experiments show that fluctuation of the flame in the supercharged boiler is intensive than that in stationary power plant boilers. Radiative Energy Signal (RES) is obtained from experiments by the flame detecting system, and it is shown that RES varies approximately linearly with the oil consumption rate and the heat absorption rate in the riser. Then, an instantaneous heat absorption rate is deduced from the real time RES by a linear equation, and a control strategy for the water level in drum by RES is proposed, in which the real time RES is used to control the flow rate of feed water in advance. Simulation results show that the fluctuating amplitude of the water level can be reduced significantly by introducing RES, and this control strategy has a great potential to improve the control quality of drum water level in the supercharged boiler. - Highlights: ? We install a flame detecting system on a marine boiler to monitor furnace combustion. ? We use flame image processing technology to analyze the boiler combustion behavior. ? A control strategy is proposed as introducing RES into the feed water control system. ? Simulation shows the drum water level overcome fluctuations by inducing RES. ? Experiments state this strategy and detecting method for improving combustion efficiency.

283

[Relationship between groundwater level in riparian wetlands and water level in the river].  

Science.gov (United States)

The development and degradation processes of riparian wetlands are significantly affected by river hydrological processes. By observing the variation of groundwater levels in riparian wetlands at the Kouma section of the Yellow River Wetland, especially that during the period of regulation for water and sediment at the Xiaolangdi Reservoir, relationship between groundwater level in riparian wetlands and flood water level in the river is studied. The results show that groundwater level in riparian wetlands is significantly affected by water level in the river investigated. There is a negative exponential relationship between groundwater level and the distance between wells and river. The correlation coefficient shows the maximum (R2 > 0.98) during the period of regulation for water and sediment. Affected by the cultivation system in the flooding area, distance between monitoring wells and river bank, water level in the river variation of groundwater level in the wetland changed greatly. In artificial wetland, which is far from the river, the inter-annual variation in groundwater levels show a " (see symbol)" shape, while in the farmland, which is close to the river, the inter-annual variation of groundwater levels show a big peak. The groundwater level 400 m from the river is affected by flood events obviously, that in the area which is less than 200 m from the river is significantly affected by flood events in the area which is especially less than that in the area that is less than 100 m from the river, the groundwater level is affected by flood events intensively. The result indicated that there was a very close relationship between groundwater and surface water, and it was the hydrological ecotone between groundwater of riparian wetlands and the river. It is very important that rational protection for this region (very important for the area which is less than 100 m from the river, important for the area that is between 100 m and 200 m from the river) is critical for the conservation of water quality in the river and groundwater quality. PMID:21528555

Xu, Hua-Shan; Zhao, Tong-Qian; Meng, Hong-Qi; Xu, Zong-Xue; Ma, Chao-Hong

2011-02-01

284

Low-level measurements of tritium in water  

International Nuclear Information System (INIS)

Using a liquid scintillation counter, an experimental procedure for measuring low-level activity concentrations of tritium in environmental water has been developed by our laboratory, using the electrolytic tritium enrichment. Additionally, some quality tests were applied in order to assure the goodness of the method. Well-known water samples collected in the Tagus River (West of Spain) and the Danube River (Bulgaria), both affected by nuclear plant releases, were analysed and results were compared to previous data. The analytical procedure was applied to drinking water samples from the public water supply of Seville and mineral waters from different springs in Spain in order to characterize its origin. Due to the very low levels of tritium in the analysed samples, some results were reported as lower than the minimum detectable activity concentration (MDA). However, the count rate of these measurements was over the background count rate of LS counter in all the cases. For that reason, an exhaustive discussion about the meaning of the MDA, using an experimental essay, was made in order to establish a rigorous criterion that leads to a reliable value in the case of low-level measurements

285

Low-level measurements of tritium in water.  

Science.gov (United States)

Using a liquid scintillation counter, an experimental procedure for measuring low-level activity concentrations of tritium in environmental water has been developed by our laboratory, using the electrolytic tritium enrichment. Additionally, some quality tests were applied in order to assure the goodness of the method. Well-known water samples collected in the Tagus River (West of Spain) and the Danube River (Bulgaria), both affected by nuclear plant releases, were analysed and results were compared to previous data. The analytical procedure was applied to drinking water samples from the public water supply of Seville and mineral waters from different springs in Spain in order to characterize its origin. Due to the very low levels of tritium in the analysed samples, some results were reported as lower than the minimum detectable activity concentration (MDA). However, the count rate of these measurements was over the background count rate of LS counter in all the cases. For that reason, an exhaustive discussion about the meaning of the MDA, using an experimental essay, was made in order to establish a rigorous criterion that leads to a reliable value in the case of low-level measurements. PMID:15177365

Villa, M; Manjón, G

2004-01-01

286

Connecting water correlations, fluctuations, and wetting phenomena at hydrophobic and hydrophilic surfaces  

OpenAIRE

We use molecular simulations to demonstrate the connection between transverse water-water correlations and wetting phenomena for a range of hydrophobic to hydrophilic solid surfaces.Near superhydrophobic surfaces, the correlations are long ranged, system spanning, and are well described by the capillary wave theory. With increasing surface-water attractions, the correlations are quenched. At the critical attraction at which long range correlations disappear, the density prof...

Godawat, Rahul; Jamadagni, Sumanth N.; Venkateshwaran, Vasudevan; Garde, Shekhar

2014-01-01

287

High levels of fluctuating asymmetry in populations of Apodemus flavicollis from the most contaminated areas in Chernobyl  

International Nuclear Information System (INIS)

Random deviations from the perfect symmetry of normally bilaterally symmetrical characters for an individual with a given genotype occur during individual development due to the influence of multiple environmental factors. Fluctuating asymmetry (FA) is often used as a measure of developmental instability, and can be estimated as the variance of the distribution of differences between the left and right sides. We addressed the question of whether levels of FA were elevated in radioactively contaminated populations living around Chernobyl compared to those in reference populations of the yellow-necked mouse (Apodemus flavicollis). In addition, we studied amounts of directional asymmetry (DA) when one side is larger than the other on average. There was a significant difference among populations, including reference populations, in the amount of both FA and DA. A higher level of FA was documented for the contaminated populations in close proximity to the failed Chernobyl reactor for both the asymmetry of size and shape. The FAs of size and shape were highest in populations from the most contaminated locations in the Chernobyl exclusion zone. Although the directional asymmetry of shape was also highest in the contaminated populations, it was not significantly different from those in most of the reference populations. Populations from less contaminated areas inside the Chernobyl exclusion zone did not express FA values different from those of the reference populations outsim those of the reference populations outside the affected area. FA of skulls of A. flavicollis may indicate the degree to which the level of radioactive contamination affects the development of animals at Chernobyl. However, the mechanisms leading to these effects are not clear and probably vary from population to population. There were significant correlations between the overall right to left differences for the Procrustes aligned shape configurations, centroid sizes, and intramuscular 137Cs. Detectable effects of radiation on developmental stability probably start to occur between 0.132 and 0.297 ?Gy/h

288

High levels of fluctuating asymmetry in populations of Apodemus flavicollis from the most contaminated areas in Chernobyl  

Energy Technology Data Exchange (ETDEWEB)

Random deviations from the perfect symmetry of normally bilaterally symmetrical characters for an individual with a given genotype occur during individual development due to the influence of multiple environmental factors. Fluctuating asymmetry (FA) is often used as a measure of developmental instability, and can be estimated as the variance of the distribution of differences between the left and right sides. We addressed the question of whether levels of FA were elevated in radioactively contaminated populations living around Chernobyl compared to those in reference populations of the yellow-necked mouse (Apodemus flavicollis). In addition, we studied amounts of directional asymmetry (DA) when one side is larger than the other on average. There was a significant difference among populations, including reference populations, in the amount of both FA and DA. A higher level of FA was documented for the contaminated populations in close proximity to the failed Chernobyl reactor for both the asymmetry of size and shape. The FAs of size and shape were highest in populations from the most contaminated locations in the Chernobyl exclusion zone. Although the directional asymmetry of shape was also highest in the contaminated populations, it was not significantly different from those in most of the reference populations. Populations from less contaminated areas inside the Chernobyl exclusion zone did not express FA values different from those of the reference populations outside the affected area. FA of skulls of A. flavicollis may indicate the degree to which the level of radioactive contamination affects the development of animals at Chernobyl. However, the mechanisms leading to these effects are not clear and probably vary from population to population. There were significant correlations between the overall right to left differences for the Procrustes aligned shape configurations, centroid sizes, and intramuscular {sup 137}Cs. Detectable effects of radiation on developmental stability probably start to occur between 0.132 and 0.297 {mu}Gy/h.

Oleksyk, Taras K. E-mail: oleksyk@ncifcrf.gov; Novak, James M.; Purdue, James R.; Gashchak, Sergiy P.; Smith, Michael H

2004-07-01

289

Analysis of Water Level Dynamics in the Great Lakes of North America  

Science.gov (United States)

Anthropogenic as well as natural fluctuations such as precipitation, runoff, snowmelt, retention time, evaporation, and outflow all contribute to water levels observed in the Great Lakes. Verified hourly water level data for five stations in Lake Michigan and four stations in Lake Superior were obtained from NOAA and examined. For each station, an hourly time series ranging from 20 to 30 years in duration was decimated to produce a time series with four hour intervals. A Fourier transform was performed on each time series and the resulting frequency information displayed in a Power Spectral Density (PSD) graph. Water level records in the Great Lakes are found to exhibit power law scaling between power spectral density and period. Four distinct regions of scaling are observed with inflection points at approximately 1 day, 5 days, and 30 - 60 days. For time scales of less than one day, the power-scaling exponent (?) ranges from 0.1 to 0.5, indicating a white noise. From 1 day to 5 - 7 days, ? ranges from 1.5 to 2.6, indicating moderate to strong persistence which we propose is due to frontal movements of weather systems. On timescales between 5 days and 30 - 60 days, ? ranges from 0.1 to 0.4, again indicating a white noise which we propose is due to monthly and seasonal weather variations within the Great Lakes System. Beyond 30 - 60 days, all stations exhibit strong persistence, with ? between 1.6 and 2.7. Analysis of physical processes using nonlinear methods such as the Fourier transform allows one to determine the natural state of the environment and if the natural state fluctuates randomly (white noise) or has some underlying order (persistence). A parallel analysis approach, drawing from concepts in control theory and feedback systems, uses Bode plots in the frequency domain and can be applied to explain variations in the Power Spectral Density plots of water levels. By analyzing the pattern of change in amplitude and phase across frequencies in a Bode plot, the dynamic properties of a system can be discerned. Bode plots draw a window into the underlying internal dynamics of the system answering questions such as the presence of time delays, the stability of the physical system, and the extent to which the system is acting as an integrator. For example, the Power Spectral Density plot of water levels in which the Beta value is near ? = 2 for time intervals from 1 day to 5 - 7 days suggests that the system is acting as an integrator over this time scale. Changes in water levels and tides have been used as an index for physical parameters such as temperature, density, and circulation (Keeling and Whorf, 1997; Denny and Paine, 1998). Long term 1/f noise (environmental noise) in the physical environment has been shown to affect populations of species embedded in these environments. Variations observed in the changing ? of water levels (environmental noise) may have biological impacts on population dynamics of organisms, including rates of survival or extinction (Batchhelder and Powell 2002). The application of Bode analysis and control theory concepts to population dynamics may provide additional insight into the underlying dynamics of the response of a population to noise found within the physical environment. Knowledge of the biological-physical coupling and the impact of environmental noise (as observed in water level data) in this aquatic environment are needed to understand the complex ecosystem dynamics.

Smigelski, J. R.; Tebbens, S. F.; Barton, C. C.

2008-12-01

290

Water level oscillations in Monterey Bay and Harbor  

Science.gov (United States)

Seiches are normal modes of water bodies responding to geophysical forcings with potential to significantly impact ecology and maritime operations. Analysis of high-frequency (1 Hz) water level data in Monterey California identifies Harbor modes between 10 and 120 s that are attributed with specific geographic features. It found that modal amplitude modulation arises from cross-modal interaction and that offshore wave energy is a primary driver of these modes. Synchronous coupling between modes is observed to significantly impact dynamic water levels. At lower frequencies between 15 and 60 min modes are independent of offshore wave energy, yet are continuously present. This is unexpected since seiches normally dissipate after cessation of the driving force, indicating an unknown forcing. Spectral and kinematic estimates of these low frequency oscillations supports the idea that a persistent anticyclonic mesoscale gyre adjacent to the Bay is a potential mode driver, while discounting other sources.

Park, J.; Sweet, W.; Heitsenrether, R.

2014-11-01

291

Levels of trace elements in MWSS drinking water  

International Nuclear Information System (INIS)

As a water supplier for the metropolis, vigilance over the water quality has not been taken for granted at the Metropolitan Waterworks and Sewerage System (MWSS). By the early 1980's, a control laboratory equipped with modern facilities had been set up to supplement the already existing control laboratory at Filter Plant II handling physical, chemical, bacteriological, biological and mineral analyses and examinations, efficiently. The new central laboratory is intended to monitor trace elements, organic constituents and other elements with health related impact so as to assure the consumers of a safe drinking water supply at all times. This presentation reviews the levels of trace element pollution in MWSS tap water, then and now, in justification of the rehabilitation projects along the distribution network, in the treatment plants and other pertinent innovations corresponding to budgeted capital outlays as invested by the system. (author)

292

An analysis of the water-level monitoring system for a boiling-water reactor  

International Nuclear Information System (INIS)

The water-level instrumentation system is very important to the overall safety of a BWR. This system is being monitored by the Safety Parameter Display System (SPDS) that is being installed in Georgia Power Company's Plant Hatch. One of the most significant functions of the SPDS is the comparison of redundant instrument readings and formation of the best estimate of each parameter from those readings which are consistent. When comparing water-level instrument readings, it is necessary to correct the individual readings for differences between current and calibration conditions as well as for differences between calibration conditions for the multiple instruments. This paper documents the examination of the water-level instrumentation system at Plant Hatch and presents the development of the equations that were used to determine the differences between indicated and actual water levels. (author)

293

Do Estimates of Water Productivity Enhance Understanding of Farm-Level Water Management?  

Directory of Open Access Journals (Sweden)

Full Text Available Estimates of water productivity are appearing with increasing frequency in the literature pertaining to agronomy, water management, and water policy. Some authors report such estimates as one of the outcome variables of experiment station studies, while others calculate water productivities when comparing regional crop production information. Many authors suggest or imply that higher values of water productivity are needed to ensure that future food production goals are achieved. Yet maximizing water productivity might not be consistent with farm-level goals or with societal objectives regarding water allocation and management. Farmers in both rainfed and irrigated settings must address a complex set of issues pertaining to risk, uncertainty, prices, and opportunity costs, when selecting activities and determining optimal strategies. It is not clear that farmers in either setting will or should choose to maximize water productivity. Upon examining water productivity, both conceptually and empirically, using published versions of crop production functions, I conclude that estimates of water productivity contain too little information to enhance understanding of farm-level water management.

Dennis Wichelns

2014-03-01

294

Calibration of Nitrate Leaching and Water Table Fluctuation in Paddy Rice Field by DRAINMOD-N Software  

Directory of Open Access Journals (Sweden)

Full Text Available Fertilizers in agriculture are potential sources of environmental pollution, especially in ground water quality and soil resources. Studying factors effective in water and nutrient transport through soil profile is helpful for nutrient management to minimize adverse impacts on environment and nitrate leaching below the root zone. In this study, the ground water level and nitrate leaching transportation below the root zone were measured in a paddy rice field and the data were simulated with the DRAINMOD-N model. For evaluating DRAINMOD-N software in a paddy rice field under surface drainage in Mazandaran, the ground water level and nitrate transportation were measured during four months (June, July, August and September in 2008. The DRAINMOD-N model was calibrated by adjusting nitrification and denitrification rate constants to reach the best fit between measured and predicted data. Results indicate that predicted ground water level and nitrate concentration by model were significant at one percent level. The statistical comparison was done by model efficiency (EF 0.84 for estimation of ground water level and 0.97 for estimation of nitrate concentration, respectively. The DRAINMOD-N model can be used as a tool to manage environmental pollution of nitrate in paddy rice fields.

H. Zare Abyaneh

2011-10-01

295

Effects of Water Levels on Productivity of Canada Geese in the Northern Flathead Valley, 1984 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

Operation of Hungry Horse Dam on the South Fork Flathead River causes sporadic level fluctuations along the main stem Flathead River. Seasonal water level fluctuations and substantial habitat losses have occurred as a result of construction and operation of Kerr Dam, which regulates Flathead Lake. These fluctuations may impact goose populations through flooding or erosion of nesting and brood-rearing habitats, and increased susceptibility of nests and young to predation. The number, location, and success of goose nests were determined through pair surveys and nest searches. Counts of indicated pairs suggest there were 73-125 occupied nests in the study area; 44 were located in 1984. Twenty were island ground nests, 19 were tree nests, and 5 were on man-made structures. Hatching success was 76 percent. Sixty-one percent of all nests were in deciduous forest habitat; 87 percent were on riparian bench or island landforms. Seventy-four percent of all nests were within 5 m of the seasonal high water mark (HWM) and 85 percent of ground nests were 1 m or less above the HWM. Production, habitat use, and distribution of broods were documented through aerial, boat, ground, and observation tower surveys. 28 refs., 10 figs., 4 tabs.

Casey, Daniel

1985-02-01

296

Evaluation of statistical properties of free-surface fluctuation on a high-speed water jet using laser refraction technique  

International Nuclear Information System (INIS)

Free-surface fluctuation on a high-speed water jet has been evaluated using a laser beam refraction technique. This technique employs two pulse laser diodes and one high-speed optic detector. By detecting the two dimensional (2D) trajectory of laser beams refracted at free surface, the local streamwise slope-angle fluctuation at two measuring locations 1.27 mm apart on a jet free surface can be evaluated. The experiments are conducted for several locations along the jet center axis within the range of average velocity up to 10 m/s. The wave speed is evaluated from dominant time lag of cross-correlation coefficient for individual wave period, which is divided from time-series slope-angle data according to the zero-up-crossing method. The shape of waves is also calculated by integrating the free-surface slope angle. The wavelength and wave height are evaluated from the individual waveform. The steepness of free surface wave takes a maximum at a certain distance from nozzle exit for U ? 8 m/s. This suggests that the initial amplification of wave results in a wave breaking on the jet free surface for these velocity conditions. (author)

297

Melatonin levels, determined by LC-ESI-MS/MS, fluctuate during the day/night cycle in Vitis vinifera cv Malbec: evidence of its antioxidant role in fruits.  

Science.gov (United States)

The identification of melatonin in plants has inspired new investigations to understand its biological function and which endogenous and external factors control its levels in these organisms. Owing to the therapeutical and nutraceutical properties of melatonin, it should be important to develop reliable analytical methods for its quantification in vegetal matrices containing this indoleamine, such as grape and wine. The main objectives of the present study were to test whether melatonin levels fluctuate during the day in berry skins of Vitis vinifera L. cv Malbec, thereby possibly relating its abundance to its putative antioxidant function, to determine whether daylight reaching clusters negatively controls melatonin levels, and to evaluate whether total polyphenols and anthocyanins also change through a 24-hr period. Grapes were harvested throughout the day/night to determine the moment when high levels of these components are present in grapes. The presence of melatonin in grapes was evaluated by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. It is shown for the first time that melatonin levels fluctuate during the day/night cycle in plants grown under field conditions in a fruit organ of the species Vitis vinifera. We also determined that the diurnal decay of melatonin in berry skins is induced by sunlight, because covered bunches retained higher melatonin levels than exposed ones, thus explaining at least part of the basis of its daily fluctuation. Evidence of melatonin's antioxidant role in grapes is also suggested by monitoring malondialdehyde levels during the day. PMID:21605162

Boccalandro, Hernán E; González, Carina V; Wunderlin, Daniel A; Silva, María F

2011-09-01

298

Fluctuations and Relaxation Dynamics of Liquid Water Revealed by Linear and Nonlinear Spectroscopy  

Science.gov (United States)

Many efforts have been devoted to elucidating the intra- and intermolecular dynamics of liquid water because of their important roles in many fields of science and engineering. Nonlinear spectroscopy is a powerful tool to investigate the dynamics. Because nonlinear response functions are described by more than one time variable, it is possible to analyze static and dynamic mode couplings. Here we review the intra- and intermolecular dynamics of liquid water revealed by recent linear and nonlinear spectroscopic experiments and computer simulations. In particular, we discuss the population relaxation, anisotropy decay, and spectral diffusion of the intra- and intermolecular motions of water and their temperature dependence, which play important roles in ultrafast dynamics and relaxations in water.

Yagasaki, Takuma; Saito, Shinji

2013-04-01

299

Quantum fluctuations and isotope effects in ab initio descriptions of water  

OpenAIRE

Nuclear quantum effects, such as zero-point energy and tunneling, cause significant changes to the structure and dynamics of hydrogen bonded systems such as liquid water. However, due to the current inability to simulate liquid water using an exact description of its electronic structure, the interplay between nuclear and electronic quantum effects remains unclear. Here we use simulations that incorporate the quantum mechanical nature of both the nuclei and electrons to prov...

Wang, Lu; Ceriotti, Michele; Markland, Thomas E.

2014-01-01

300

Biodegradation of Toluene Under Seasonal and Diurnal Fluctuations of Soil-Water Temperature  

OpenAIRE

An increasing interest in bioremediation of hydrocarbon polluted sites raises the question of the influence of seasonal and diurnal changes on soil-water temperature on biodegradation of BTEX, a widespread group of (sub)-surface contaminants. Therefore, we investigated the impact of a wide range of varying soil-water temperature on biodegradation of toluene under aerobic conditions. To see the seasonal impact of temperature, three sets of batch experiments were conducted at three different co...

Yadav, B. K.; Shrestha, S. R.; Hassanizadeh, S. M.

2012-01-01

301

Quality Level of Bottled Drinking Water Consumed in Saudi Arabia  

Directory of Open Access Journals (Sweden)

Full Text Available The quality of drinking water is a universal health concern and access to safe water is a fundamental human right. Many national and international organizations set certain parameters and levels for Bottled Drinking Water (BDW to ensure their quality. The present work aims to analyze the quality of various brands of BDW used in Saudi Arabia and to compare the quality levels to the BDW standards. One hundred and twenty six samples of 54 different BDW brands were collected from the Saudi market. The quality level parameters were analyzed using portable meters for pH, EC and TDS; spectrophotometer, HACH DR-2800 for F, SO4 and NO3; Inductively Coupled Plasma (ICP Mass Spectrometer (MS and atomic emission spectrometer (AES for elemental analysis. To evaluate the quality level parameters of BDW, the parameters were classified as following: (1 Parameters and substances affect the quality of BDW (pH, EC, TDS, HCO3, F, NO3 and SO4. (2 Macronutrients (Ca, K, Mg and Na. (3 Micronutrients-trace elements (Co, Cr, Cu, Fe, Mo, Se and Zn, (4 Potentially essential elements that have some beneficial health effects (B, Mn, Ni and V and (5 Toxic elements (Al, As, Cd, Hg, Pb, Th and U using Inductively coupled plasma-mass spectrometry, ICP-MS. The concentrations of the detected elements were compared with the Golf and international standard like World Health Organization.

Ashraf E.M. Khater

2014-01-01

302

Modelling the impact of climate change on groundwater in the UK. Stage 2 report, using an unsaturated zone transfer function to model groundwater level fluctuations  

OpenAIRE

This report describes work carried out as part of the second stage of the joint BGS-CEH project “Modelling the impact of climate change on groundwater in the UK”. The work described in the report involved testing and developing a simple approach to the reproduction of historical groundwater level fluctuations. The technique makes use of an unsaturated zone transfer function to represent delayed recharge. The model was used to replicate long-term groundwater level records fr...

O Dochartaigh, B. E.

2001-01-01

303

Investigation of the Relationship between Groundwater Level Fluctuation and Vegetation Cover by using NDVI for Shaqlawa Basin, Kurdistan Region – Iraq  

Directory of Open Access Journals (Sweden)

Full Text Available Groundwater as an important component of the hydrological cycle and it is the main resource for irrigation and domestic water supply particularly in arid and semi-arid area, where groundwater is a key feature that controls the distribution of vegetation. Distribution of vegetation was compared in the Shaqlawa Basin located in Kurdistan Region, Northern Iraq with the depth to groundwater by using the normalize difference vegetation index (NDVI and the normalize different moisture index (NDMI. The NDVI and NDMI were derived from TM-5 images from 2006, 2007, 2009, 2010, and 2011. Depths to groundwater measurements were available from 11 monitoring wells. The results of statistical analysis show significant relationship between groundwater table and calculated vegetated areas at the 95% confidence levels with P-value less than 0.05 for all modeled years. The NDVI values at different depth to groundwater intervals indicate that higher vegetation coverage and more plant diversity exist in areas of shallow groundwater. Drought periods affected the groundwater table and less water infiltrating into soil, then the agricultural decreased. The scarcity of precipitation and other sources for fresh water increase the demand on groundwater water in agricultural activities in the region.

Shwan Seeyan

2014-06-01

304

Holocene lake level fluctuations of a small alpine lake in the Qilian Mountains, NW China: a comparison of chironomid, ostracod, pollen and geochemistry data.  

Science.gov (United States)

A core of 14 m length was drilled in a small alpine lake in the Qilian Mountains, NW China. The lake Luanhaizi has a drainage area of about 30 km2 and is situated at an altitude of 3200 m which represents the altitude of the present regional upper timberline. Due to the small size of the open-basin lake (surface area about 1 km2) and the sharply outlined catchment area the lake is regarded as a very sensitively and rapidly responding ecosystem. Analyses of ostracod shells, head capsules of larval chironomids and pollen and spores were conducted and the organic and carbonate content (LOI), element concentrations and magnetic susceptibility of core samples determined. Ostracod taxa mainly comprise Candona candida, C. neglecta, C. rawsoni, Cyclocypris ovum, Cypridopsis vidua, Fabaeformiscandona caudata, F. danielopoli, F. hyalina, Herpetocypris chevreuxi, Heterocypris salina, Ilyocypris cf. bradyi, I. echinata, I. lacustris and Limnocythere inopinata. They may be used to distinguish periods of low lake levels corresponding to a dense cover of aquatic plants at the lake bottom from stages of higher lake levels and a corresponding decrease in macrophytes at the core site. Chironomid taxa belonging to Chironomus, Cladopelma, Glyptotendipes, Micropsectra, Paratanytarsus, Polypedilum, Psectrocladius and Tanytarsus further provide information on variations in benthic oxygen availability and lake level fluctuations. Several units of the core show high abundances of pollen and spores of higher aquatic and wetland plants and fungi (Cyperaceae, Hippuris, Myriophyllum and Glomus) indicating low lake levels. In contrast, algae such as Botryococcus, Pediastrum and Tetraedron were regarded to reflect higher water levels. Typha angustifolia-type, Typha latifolia, Alisma and Potamogeton were recorded in low abundances as well. The organic content of core samples averages 6 % displaying four alternating stages of distinct minima and maxima. Lowest values of about 1 % occur at the core base whereas the organic content rises to 16 % at maximum near the top. The carbonate content displays a similar pattern with strong shifts ranging from 3 to 31%. The results of the investigation of the sediment core from the alpine lake in the Qilian Mountains were presented and the validity of single proxies with respect to lake level changes discussed.

Mischke, S.; Herzschuh, U.

2003-04-01

305

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

Science.gov (United States)

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. PMID:25217744

Smiljani?, Marko; Seo, Jeong-Wook; Läänelaid, Alar; van der Maaten-Theunissen, Marieke; Staji?, Branko; Wilmking, Martin

2014-12-01

306

Analytical approach for predicting fresh water discharge in an estuary based on tidal water level observations  

Directory of Open Access Journals (Sweden)

Full Text Available As the tidal wave propagates into an estuary, the tidally averaged water level tends to rise in landward direction due to the density difference between saline and fresh water and the asymmetry of the friction. The effect of friction on the residual slope is even more remarkable when accounting for fresh water discharge. In this study, we investigate the influence of river discharge on tidal wave propagation in the Yangtze estuary with specific attention to residual water level slope. This is done by using a one-dimensional analytical model for tidal hydrodynamics accounting for the residual water level. We demonstrate the importance of the residual slope on tidal dynamics and use it to improve the prediction of the tidal propagation in estuaries (i.e., tidal damping, velocity amplitude, wave celerity and phase lag, especially when the influence of river discharge is significant. Finally, we develop a new inverse analytical approach for estimating fresh water discharge on the basis of tidal water level observations along the estuary, which can be used as a tool to obtain information on the river discharge that is otherwise difficult to measure in the tidal region.

H. Cai

2014-06-01

307

Glassy Interfacial Dynamics of Ni Nanoparticles: Part II Discrete Breathers as an Explanation of Two-Level Energy Fluctuations.  

Science.gov (United States)

Recent studies of the dynamics of diverse condensed amorphous materials have indicated significant heterogeneity in the local mobility and a progressive increase in collective particle motion upon cooling that takes the form of string-like particle rearrangements. In a previous paper (Part I), we examined the possibility that fluctuations in potential energy E and particle mobility ? associated with this 'dynamic heterogeneity' might offer information about the scale of collective motion in glassy materials based on molecular dynamics simulations of the glassy interfacial region of Ni nanoparticles (NPs) at elevated temperatures. We found that the noise exponent associated with fluctuations in the Debye-Waller factor, a mobility related quantity, was directly proportional to the scale of collective motion L under a broad range of conditions, but the noise exponent associated with E(t) fluctuations was seemingly unrelated to L. In the present work, we focus on this unanticipated difference between potential energy and mobility fluctuations by examining these quantities at an atomic scale. We find that the string atoms exhibit a jump-like motion between two well-separated bands of energy states and the rate at which these jumps occur seems to be consistent with the phenomenology of the 'slow-beta' relaxation process of glass-forming liquids. Concurrently with these local E(t) jumps, we also find 'quake-like' particle displacements having a power-law distribution in magnitude so that particle displacement fluctuations within the strings are strikingly different from local E(t) fluctuations. An analysis of these E(t) fluctuations suggests that we are dealing with 'discrete breather' excitations in which large energy fluctuations develop in arrays of non-linear oscillators by virtue of large anharmonicity in the interparticle interactions and discreteness effects associated with particle packing. We quantify string collective motions on a fast caging times scale (picoseconds) and explore the significance of these collective motions for understanding the Boson peak of glass-forming materials. PMID:23585770

Zhang, Hao; Douglas, Jack F

2013-01-01

308

Ditch water levels manages for environmental aims: effects on field soil water regimes  

Directory of Open Access Journals (Sweden)

Full Text Available The effects of ditch water management regimes on water tables are examined for two test sites in England, Halvergate in the Broads and Southlake Moor in the Somerset Levels and Moors Environmentally Sensitive Areas. It is observed that in some fields the effects of water management are only poorly transferred from the ditch to the field centre, especially where the hydraulic conductivity of the subsoil is small. Where there are large variations in the ditch water levels, reflecting the influence of major ditches subject to pump drainage, field soil water regimes differ significantly. Nevertheless, the effects of even quite small changes in the ditch regime cam be noticeable. Simple modelling studies show that much greater effects can be achieved by increasing the frequency of ditches within wetlands.

A. Armstrong

1999-01-01

309

The Water Level Fall of Lake Megali Prespa (N Greece): an Indicator of Regional Water Stress Driven by Climate Change and Amplified by Water Extraction?  

Science.gov (United States)

The Mediterranean stands out globally due to its sensitivity to (future) climate change, with future projections predicting an increase in excessive drought events and declining rainfall. Regional freshwater ecosystems are particularly threatened: precipitation decreases, while extreme droughts increase and human impacts intensify (e.g. water extraction, drainage, pollution and dam-building). Many Mediterranean lake-wetland systems have shrunk or disappeared over the past two decades. Protecting the remaining systems is extremely important for supporting global biodiversity and for ensuring sustainable water availability. This protection should be based on a clear understanding of lake-wetland hydrological responses to natural and human-induced changes, which is currently lacking in many parts of the Mediterranean. The interconnected Prespa-Ohrid Lake system is a global hotspot of biodiversity and endemism. The unprecedented fall in water level (~8m) of Lake Megali Prespa threatens this system, but causes remain debated. Modelling suggests that the S Balkan will experience rainfall and runoff decreases of ~30% by 2050. However, projections revealing the potential impact of these changes on future lake level are unavailable as lake regime is not understood. A further drop in lake level may have serious consequences. The Prespa Lakes contribute ~25% of the total inflow into Lake Ohrid through underground karst channels; falling lake levels decrease this discharge. Lake Ohrid, in turn, feeds the Drim River. This entire catchment may therefore be affected by falling lake levels; its water resources are of great importance for Greece, Albania, FYROM and Montenegro (e.g. tourism, agriculture, hydro-energy, urban & industrial use). This new work proves that annual water level fluctuations of Lake Megali Prespa are predominantly related to precipitation during the first 7 months (Oct-Apr) of the hydrological year (Oct-Sep). Lake level is very sensitive to regional and Mediterranean wet-dry events during this period. There are robust indications for a link between lake level and the North Atlantic Oscillation, which is known to strongly influence Mediterranean winter precipitation. Hydro-climatic records show a complicated picture, but tentatively support the conclusion that the unprecedented lake level fall is principally related to climate change. The available fluvial discharge record and most existing snowfall records show statistically significant decreases in annual averages. Annual rainfall only shows a statistically significant decrease of the 25th percentile; 7-month rainfall (Oct-Apr) additionally shows a statistically significant but non-robust decrease of the mean. The modest amount of water extraction (annually: ~14*103m3, ~0.004% of total lake volume) exerts a progressive and significant impact on lake level over the longer term, accounting for ~25% of the observed fall. Lake level lowering ends when lake-surface area shrinkage has led to a decrease in lake-surface evaporation that is equivalent to the amount of water extracted. The adjustment of lake level to stable extraction rates requires two to three decades. This work aims to steer adaptation and mitigation strategies by informing on lake response under different climate change and extraction scenarios. Lake protection is a cost effective solution for supporting global biodiversity and for providing sustainable water resources.

van der Schriek, Tim; Giannakopoulos, Christos

2014-05-01

310

Lead levels in fresh water mollusk shells. [Corbicula manillensis  

Energy Technology Data Exchange (ETDEWEB)

The possibility of using the shells of various fresh water mollusks as indicators of lead levels has been investigated. Shells of Corbicula manillensis (Asiatic clam) were found to be reliable and readily available indicators of lead levels. Samples collected at a relatively clean site were found to yield a mean lead concentration of 0.6 ppM with a range of .1 to 1.3 ppM. The sample means from other sites were increased by factors between 2 and 3.

Clarke, J.H.; Clarke, A.N.; Wilson, D.J.; Friauf, J.J.

1976-01-01

311

Investigation of natural radioactivity levels in water around Kadugli, Sudan  

International Nuclear Information System (INIS)

Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for 238U, 226Ra, 222Rn, and 232Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: -1 for 238U, 226Ra, 222Rn, and 232Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, -1) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr-1 except in one groundwater sample with an associated dose of 0.7 mSv yr-1

312

Investigation of natural radioactivity levels in water around Kadugli, Sudan.  

Science.gov (United States)

Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for (238)U, (226)Ra, (222)Rn, and (232)Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: <1.0-7.5, 8.5-16.5, <1.6, and <0.1-0.39 mBq L(-1) for (238)U, (226)Ra, (222)Rn, and (232)Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, <0.1-39 mBq L(-1)) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr(-1) except in one groundwater sample with an associated dose of 0.7 mSv yr(-1). PMID:18513978

Osman, Alfatih A A; Salih, Isam; Shaddad, Ibrahim A; El Din, Saif; Siddeeg, M B; Eltayeb, Hatem; Idriss, Hajo; Hamza, Walid; Yousif, E H

2008-11-01

313

Predictive Adaptive Control of water level in canal pools  

OpenAIRE

A case study on the use of a predictive adaptive algorithm to control pool level in a pilot water distribuition canal is described. The algorithm is a modification of the basic MUSMAR controller that includes parallel integral action and, in the case of multiple pools, feedforward action to coordinate the gates. Experimental results in the case of a single pool and simulations for multiple pools are presented. The contributions of the paper stem from the explicitation of rules for...

Lemos, Joa?o Miranda; Rato, Lui?s; Machado, Fernando; Nogueira, Nuno; Salgueiro, Pedro; Rijo, Manuel

2007-01-01

314

Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake, 1985 Annual Report.  

Energy Technology Data Exchange (ETDEWEB)

This study has investigated the effects of the operation of Kerr Dam on the reproductive success of kokanee that spawn along the shores of Flathead Lake. We have estimated the spawning escapement to the lakeshore, characterized spawning habitat, monitored egg and alevin survival in redds, and related survival to length of redd exposure due to lake drawdown. Groundwater discharge apparently attracts kokanee to spawning sites along the lakeshore and is responsible for prolonging egg survival in redds above minimum pool. We have quantified and described the effect of lake drawdown on groundwater flux in spawning areas. This report defines optimal lakeshore spawning habitat and discusses eqg and alevin survival both in and below the varial zone.

Beattie, Will; Fraley, John J.; Decker-Hess, Janet (Montana Department of Fish, Wildlife and Parks, Kalispell, MT)

1986-06-01

315

Primary collector wall local temperature fluctuations in the area of water-steam phase boundary  

Energy Technology Data Exchange (ETDEWEB)

A limited number of temperature sensors could be installed at the primary collector surface in the area of water - steam phase boundary. The surface temperatures as well WWER 440 steam generator process data were measured and stored for a long time and off-line evaluated. Selected results are presented in the paper. (orig.). 2 refs.

Matal, O.; Klinga, J.; Simo, T. [Energovyzkum Ltd., Brno (Switzerland)

1995-12-31

316

Primary collector wall local temperature fluctuations in the area of water-steam phase boundary  

International Nuclear Information System (INIS)

A limited number of temperature sensors could be installed at the primary collector surface in the area of water - steam phase boundary. The surface temperatures as well WWER 440 steam generator process data were measured and stored for a long time and off-line evaluated. Selected results are presented in the paper. (orig.)

317

Flow in a limestone aquifer as determined from water tracing and water levels in wells  

Science.gov (United States)

The Inner Bluegrass Karst Region of central Kentucky, U.S.A., is a fluviokarst underlain by flat-lying slightly argillaceous limestones (Ordovician). Water tracing and field observations have shown the aquifer to be divisible into groundwater basins and intervening interbasin areas. Flow in groundwater basins is in a dendritic system of solution conduits at depths as great as 35 m beneath the surface which often passes beneath surface divides to emerge at low-level springs, in contrast to interbasin areas in which the flow is shallow and generally parallels surface slopes. The availability of relatively dense water-level data in an area in which a number of water traces had been conducted allowed a comparison between the configuration of the potentiometric surface and water tracing data. The potentiometric surface map was generally consistent with the location of groundwater basins and interbasin areas. In addition, water levels near streams were found to be controlled by the stream and a few wells indicated perched aquifers. The potentiometric surface, however, failed to show narrow groundwater basins and did not adequately indicate groundwater flow directions previously established by water tracing. Although well data may furnish valuable supplemental information, it is concluded that water tracing is necessary to determine adequately subsurface flow directions in the region and in similar karst aquifers elsewhere.

Thrailkill, John

1985-05-01

318

Fluctuations of mineral nitrogen and phosphate in river water during periods of various wetness  

OpenAIRE

Biological indicators are the best indicators of water quality, since they are interpretive of a variety of stressors. Analysis of scientific literature shows that substance flows are calculated using different methods. One of the goals of this work is to investigate various methods for calculating biological indicator flows and to compare differences among them. For the four biological substance calculation methods which were studied, an essential difference among them was the period during ...

Bagdz?iu?naite?-litvinaitiene?, Lina

2005-01-01

319

Ground-water monitoring at Santa Barbara, California; Phase 2, effects of pumping on water levels and water quality in the Santa Barbara ground-water basins  

Science.gov (United States)

From July 1978 to January 1980, water levels declined more than 100 feet in the coastal area of the Santa Barbara ground-water basin in southern California. The water-level declines are the result of increases in municipal pumping since July 1978. The pumping, centered in the city less than 1 mile from the coast, has caused water-level declines in the main water-bearing zones to altitudes below sea level. Consequently, the ground-water basin is threatened with salt-water intrusion if the present pumpage is maintained or increased. Water-quality data suggest that salt-water intrusion has already degraded the water yielded from six coastal wells. Chloride concentrations in the six wells ranged from about 400 to 4,000 milligrams per liter. Municipal supply wells near the coast currently yield water of suitable quality for domestic use. There is, however, no known physical barrier to the continued inland advance salt water. Management alternatives to control salt-water intrusion in the Santa Barbara area include (1) decreasing municipal pumping, (2) increasing the quantity of water available for recharge by releasing surplus water to Mission Creek, (3) artificially recharing the basin using injection wells, and (4) locating municipal supply wells farther from the coast and farther apart to minimize drawdown. (USGS)

Martin, Peter

1982-01-01

320

The Effect of Water Level on The Effectiveness of Sediment Flushing  

OpenAIRE

This research is focused on determining the effective flushing water level in pressure flushing activity at storage sedimen based on the hydraulic physical model test in the laboratory. The effective water level is the elevation of water level in sediment flushing which result in the highest concentration of sediment scours. Effective flushing water level is the elevation of water level near the top layer of sediment deposit which can trigger the erosion of the top layer of sedime...

Suripin, S.; Pranoto Samto Atmodjo

2012-01-01

321

Littoral zones in shallow lakes. Contribution to water quality in relation to water level regime  

OpenAIRE

Littoral zones with emergent vegetation are very narrow or even lacking in Dutch shallow lakes due to a combination of changed water level regime and unfavorable shore morphometry. These zones are important as a habitat for plants and animals, increasing species diversity. It has also been demonstrated that littoral zones can act as a nutrient sink to improve water quality. Therefore, it is important to understand how these zones can be restored or created and if they can be effective in this...

Sollie, S.

2007-01-01

322

CRC technology of nozzle. Water level instrumentation nozzle  

International Nuclear Information System (INIS)

Inconel 182 is used for welding joint material between Reactor Pressure Vessel (RPV) nozzle and nozzle safe-end in nuclear power plants (Nozzle indicates an only water level instrumentation nozzle in this paper). Corrosion Resistant Cladding (CRC) is the method which is welded a Stress Corrosion Cracking (SCC) resistant material cladding to the welding joint portion. Still more CRC technology is applied to the internal surface of nozzle made of Inconel 600 which is known to have SCC sensitivity. This technology prevents from the SCC initiation of material. In actual work after cutting nozzle safe-end, small-sized welding machine is put into the nozzle whose inside diameter is about 50 mm. These nozzles are installed at the three different levels of RPV. In case of the lowest nozzle, which placed near the core, it is necessary to build the shielding blocks outside RPV, and keep the reactor water in the vessel to protect workers' radiation exposure. Therefore a water-proof working box is installed around nozzle area inside RPV to perform CRC in dry environment. This technology had been applied to a couple of operating plants. (author)

323

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

Science.gov (United States)

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. PMID:24328425

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

2014-01-21

324

Study on convective mixing phenomena in parallel triple-jet along wall. Comparison of temperature fluctuation characteristics between sodium and water  

International Nuclear Information System (INIS)

Full text of publication follows: When temperature fluctuation due to convective mixing between hot and cold fluids is transferred to structure, there is a possibility of high cycle thermal fatigue. In a fast reactor sodium is used as coolant. Many experiments and calculations using water as working fluid have been carried out for the temperature fluctuations. As regarding sodium there are few experimental data. Sodium has approximately a 100 times larger thermal conductivity than water though dynamic viscosity is the same order. So temperature fluctuation characteristics in sodium will be different from that in water. Especially, decay characteristics of temperature fluctuation near a wall surface are strongly influenced by thermal property of fluid in a boundary layer. This is of importance to evaluate transfer characteristics of temperature fluctuation from fluid to structure. Here, sodium and water experiments were performed using the same geometry of the test sections. These experimental apparatuses have parallel triple jets sandwiched with two partition plates. The triple jets flow vertically along a wall with convective mixing among the jets. The jet in the center is cold, and two jets in both sides are hot. The discharged velocities of the triple jets were 0.5 m/s in both experiments. The temperature data were obtained by movable thermocouple trees, which consisted of 25 to 40 thermocouples. The temperatures were measured at 0.5 mm from the wall surface to thered at 0.5 mm from the wall surface to the center position between the two partition plates. In addition, a particle image velocimetry was applied to the water experiment. As for the time-averaged temperature field at the furthest position from the wall, the hot jets were inclined toward the cold jet in both experiments. Temperature fluctuation intensity was high in the region where the cold jet met the hot jets. A prominent frequency was observed in temperature fluctuation where the cold jet contacted the hot jets; it was resulted from oscillation of the jets. Both sodium and water experiments showed the same tendency of frequency characteristics at the furthest position from the wall surface, and the prominent frequency in sodium was the same as that in water. Temperature fluctuation intensity in sodium is small at the neighborhood of the wall surface in comparison with that at the furthest position from the wall. In water case, on the other hand, temperature fluctuation intensity near the wall was slightly larger than that at the furthest position from the wall. In sodium, the power spectrum density (PSD) near the wall was close to the PSD at the furthest position from the wall. In water, however, the prominent frequency diminished in the PSD near the wall. The vanished frequency component was shifted to the lower frequency components. The space distributions and frequency characteristics of temperature fluctuations were obtained and differences were discussed with fluid property in sodium and water experiments. (authors)

325

Predicting atrazine levels in water utility intake water for MCL compliance.  

Science.gov (United States)

To protect human health, atrazine concentrations in finished municipal drinking water must not exceed a maximum contaminant level (MCL) of 3 microg/L, as determined by a specific monitoring regime mandated by the United States Environmental Protection Agency. Atrazine levels were monitored along tile-fed drainage ditches draining to a major drinking water source and used to predict MCL exceedance frequencies of intake and finished drinking water. Water samples were collected daily at eight monitoring sites located at the outlets of subbasins draining 298-19 341 ha (736-47 794 ac). Flow-weighted average (FWA) atrazine concentrations ranged from 0.9 to 9.8 microg/L, and were above 3 microg/L for the majority of sites, including the largest site, which represents water quality at the intake of the local municipal water treatment plant. However, a relatively low percentage of samples near the water utility intake exceeding 3 microg/L atrazine (10.4%) made this problem difficult to detect. In order to have a 95% probability of detecting any intake sample exceeding 3 microg/L atrazine in a drainage system exceeding 3 microg/L atrazine on a FWA basis, sampling frequency would need to be every 7 days or more often during the second quarter when the potentials for field atrazine losses and temporal variability of atrazine concentrations are highest. PMID:18939527

Pappas, E A; Huang, C

2008-10-01

326

Fluctuations in the meiofauna of the Aufwuchs community in a brackish-water lagoon  

Science.gov (United States)

The organization of the Aufwuchs community in a brackish-water lagoon (Swanpool, Falmouth, U.K.) is described. Changes in the population densities of encrusting bryozoans and mobile meiofauna are described for a period of 3 years. Most meiofaunal species reached peak densities in the spring (January-March). These included tardigrades ( Macrobiotus sp.), oligochaetes ( Nais elinguis, Chaetogaster diaphanus), the harpacticoid copepod Schizopera clandestina, ostracods, the nematodes Dichromadora geophila and Theristus spp., and possibly the nematodes Chromadorina germanica and Atrochromadora microlaima. Other meiofaunal populations peaked in summer (July-September), and these included the chironomid Chironomus salinarius, the harpacticoid copepod Nitocra spinipes and the nematode Adoncholaimus thalassophygas. Two further species, the mite Halacarus balticus and the nematode Aphelencoides sp., showed irregular bursts in numbers. It is concluded that the spring-peaking species increased in numbers dependent upon the growth of the Aufwuchs, and particularly of the surface film of diatoms, while the summer-peaking species may have been controlled more by limiting values of salinity and temperature. These conclusions are contrasted with the general view of salinity as the over-riding factor in brackish-water ecosystems.

Little, Colin

1986-08-01

327

Variation of Great Lakes Water Levels Derived from Geosat Altimetry  

Science.gov (United States)

A technique for using satellite radar altimetry data to estimate the temporal variation of the water level in moderate to large lakes and enclosed seas is described. Great Lakes data from the first 2 years of the U.S. Navy's Geosat Exact Repeat Mission (November 1986 to November 1988), for which there is an improved orbit, are used to demonstrate the technique. The Geosat results are compared to the lake level data collected by the Great Lakes Section, National Ocean Service, National Oceanic and Atmospheric Administration, and are found to reproduce the temporal variations of the five major lakes with Root-Mean-Square error (RMS) ranging from 9.4 to 13.8 cm and a combined average of 11.1 cm. Geosat data are also analyzed for Lake St. Clair, representing a moderate-sized lake, with a resulting rms of 17.0 cm. During this study period, the water level in the Great Lakes varied in a typical annual cycle of about 0.2 m (0.5 in for Lake Ontario) superimposed on a general decline of approximately 0.5 m. The altimeter data reproduced the general decline reasonably well for all the lakes, but the annual cycle was obscured in some lakes due to systematic errors in the altimeter data. Current and future altimetry missions will have markedly improved accuracy which will permit many moderate (25 km diameter) or larger lakes or enclosed seas to be routinely monitored.

Morris, Charles S.; Gill, Stephen K.

1994-01-01

328

An Indirect Adaptive Controller to Regulate UTSG Water Level in Pressurized Water Nuclear Reactor  

Directory of Open Access Journals (Sweden)

Full Text Available Stabilizing water level of the Steam Generator (SG in nuclear power plant is a very important problem since its parameters vary with operating conditions and dynamics of the system is very different according to the power levels and changes as time goes on. Therefore, it is an intractable as well as challenging task to improve the water level control system of the SG. In this study, a new framework for building an adaptive Minimum Variance controller for stabilizing water-level of SG is proposed. We use the recursive least squares algorithm to identify the Input/Output models. Minimum Variance Control (MVC law is also used to develop the adaptation controller. Emphasis is put on the evaluation of the parameter identification in order to avoid instabilities because of disturbances or insufficient excitations. This is especially of importance when the adaptive control is carried out in closed loop systems and without additional test signals. The algorithm so proposed is simulated and applied to the water level control in the U-Tube Steam Generating unit (UTSG used for electricity generation. It is shown through application to a nonlinear model of steam generators that the proposed controller has good performance.

Djamel Boukhetala

2012-01-01

329

Phylogeography of the Mekong mud snake (Enhydris subtaeniata): the biogeographic importance of dynamic river drainages and fluctuating sea levels for semiaquatic taxa in Indochina  

OpenAIRE

During the Cenozoic, Southeast Asia was profoundly affected by plate tectonic events, dynamic river systems, fluctuating sea levels, shifting coastlines, and climatic variation, which have influenced the ecological and evolutionary trajectories of the Southeast Asian flora and fauna. We examined the role of these paleogeographic factors on shaping phylogeographic patterns focusing on a species of semiaquatic snake, Enhydris subtaeniata (Serpentes: Homalopsidae) using sequence data from three ...

Lukoschek, Vimoksalehi; Osterhage, Jennifer L.; Karns, Daryl R.; Murphy, John C.; Voris, Harold K.

2011-01-01

330

Differential equations governing slip-induced pore-pressure fluctuations in a water-saturated granular medium  

Science.gov (United States)

Macroscopic frictional slip in water-saturated granular media occurs commonly during landsliding, surface faulting, and intense bedload transport. A mathematical model of dynamic pore-pressure fluctuations that accompany and influence such sliding is derived here by both inductive and deductive methods. The inductive derivation shows how the governing differential equations represent the physics of the steadily sliding array of cylindrical fiberglass rods investigated experimentally by Iverson and LaHusen (1989). The deductive derivation shows how the same equations result from a novel application of Biot's (1956) dynamic mixture theory to macroscopic deformation. The model consists of two linear differential equations and five initial and boundary conditions that govern solid displacements and pore-water pressures. Solid displacements and water pressures are strongly coupled, in part through a boundary condition that ensures mass conservation during irreversible pore deformation that occurs along the bumpy slip surface. Feedback between this deformation and the pore-pressure field may yield complex system responses. The dual derivations of the model help explicate key assumptions. For example, the model requires that the dimensionless parameter B, defined here through normalization of Biot's equations, is much larger than one. This indicates that solid-fluid coupling forces are dominated by viscous rather than inertial effects. A tabulation of physical and kinematic variables for the rod-array experiments of Iverson and LaHusen and for various geologic phenomena shows that the model assumptions commonly are satisfied. A subsequent paper will describe model tests against experimental data. ?? 1993 International Association for Mathematical Geology.

Iverson, R.M.

1993-01-01

331

The Organochlorine Pesticides Residue Levels in Karun River Water  

Directory of Open Access Journals (Sweden)

Full Text Available Background: The organochlorine pesticides (OCPs are among the most commonly used in water streams around the world. Most of these contaminants are highly hydrophobic and persist in sediments of rivers and lakes. Studies have suggested that OCPs may affect the normal function of the human and wildlife endocrine systems.Objectives: The aim of this study is to determine the concentrations of selected organochlorine pesticides residues [OP'DDT, PP'DDT, alderin, dieldrin, heptachlor, (?,ß,?,? HCH, (?, ß endosulfan and metoxychlor] in samples from Karun River water at Khuzestan province in Iran , by GC-µ-ECD.Materials and Methods: Water was extracted with n-hexane and then purified by passing through a glass column packed with Florisil and Na2SO4, which was then eluted with ether: hexane solution v/v.Results: In general, all of 12 investigated organochlorine pesticides (OCPs were detected. Regardless of the kind of OCPs, the highest OCP pollution level in Karun River were seen from August to November 2009 ranging 71.43 – 89.34 µg/L, and the lowest were seen from Dec 2010 to March 2011 at levels of 22.25 - 22.64 µg/L. The highest and lowest mean concentrations of 12 investigated pesticides were ß-Endosulfan and pp' DDT with 28.51and 0.01 µg/L respectively.Conclusions: Comparison of total organochlorine pesticides residues concentration with WHO guidelines revealed that the Karun River had total OCPs residues above the probable effect level (0.2-20 µg/L, P < 0.05, which could pose a risk to aquatic life.

Behrooz Jannat

2013-01-01

332

Stable isotope fingerprint of open-water evaporation losses and effective drainage area fluctuations in a subarctic shield watershed  

Science.gov (United States)

SummaryStable isotopes of water, oxygen-18 and deuterium, were measured at biweekly to monthly intervals during the open-water season in a small, headwater lake (Pocket Lake, 4.8 ha) near Yellowknife Northwest Territories, and concurrently in a nearby string-of-lakes watershed (Baker Creek, 137 km 2) situated in the subarctic Precambrian Shield region. As measured in water samples collected over a 12 year period (1997-2008), the levels of evaporative isotopic enrichment in both lake and watershed outflow were differentially offset, and seasonal variations were found in both to be driven by variations in open-water evaporation. Systematic differences measured in the magnitude of the offset between the lake and watershed outflow are interpreted as being caused by changes in the effective drainage area contributing to runoff. Based on the observed and extremely consistent relationship between isotopic compositions of lake water and watershed outflow ( r2 = 0.849, p water evaporation losses and effective drainage areas back to 1991 when less-frequent water sampling at the sites commenced. This 18-year record serves to demonstrate for the first time the expected variability in the evaporation and transpiration partitioning, upper limits on the effective drainage area, and isotopic signals transferred downstream in a typical shield drainage system within the Mackenzie Basin.

Gibson, J. J.; Reid, R.

2010-02-01

333

Optimum Water Level for Spent Fuel Pool using MCNP Code  

International Nuclear Information System (INIS)

TRIGA reactor (RTP) has been operated for more than 30 years. Some of the part of the reactor become degraded by the time. Sooner or later, all these part either will be changed with a new part and proceed with upgrading plan or the reactor itself will be decommissioned. By that time, spent fuel pool (SFP) need to be ready to keep all the fuel from the core. The conceptual design of the SFP has been established. This paper will determine optimum water level to avoid any radiation hazard expose to the workers during managing the fuel later. This determination will use MCNP computer code. (author)

334

Formal specification and animation of a water level monitoring system  

International Nuclear Information System (INIS)

This report describes the Vienna Development Method (VDM), which is a formal method for software specification and development. VDM evolved out of attempts to use mathematics in programming language specifications in order to avoid ambiguities in specifications written in natural language. This report also describes the use of VDM for a real-time application, where it is used to formally specify the requirements of a water level monitoring system. The procedures and techniques used to produce an executable form (animation) of the specification are covered. (Author)

335

A near uniform basin-wide sea level fluctuation over the Japan/East Sea: A semienclosed sea with multiple straits  

Science.gov (United States)

Sea level of the Japan/East Sea observed by the TOPEX/Poseidon (T/P) satellite altimeter is analyzed using a 1/4°-resolution ocean general circulation model. A significant fraction of the Japan/East Sea sea level variability is found to be spatially uniform with periods ranging from 20 d to a year. The model simulation is consistent with T/P records in terms of the basin-wide sea level fluctuation's spectral energy and coherence. The simulation indicates that the changes are barotropic in nature and controlled, notably at high frequencies, by the net mass transport through the straits of the Japan/East Sea driven by winds in the vicinity of the Korea/Tsushima and Soya Straits. A series of barotropic simulations suggest that the sea level fluctuations are the result of a dynamic balance at the straits among near-strait winds, friction, and geostrophic control. The basin-wide sea level response is a linear superposition of changes due to winds near the individual straits. In particular, a basin-wide sea level response can be established by winds near either one of the straits alone. For the specific geometry and winds, winds near the Soya Strait have a larger impact on the Japan/East Sea mean sea level than those near the Korea/Tsushima Strait.

Kim, Seung-Bum; Fukumori, Ichiro

2008-06-01

336

Fluctuating lattice Boltzmann  

OpenAIRE

The lattice Boltzmann algorithm efficiently simulates the Navier Stokes equation of isothermal fluid flow, but ignores thermal fluctuations of the fluid, important in mesoscopic flows. We show how to adapt the algorithm to include noise, satisfying a fluctuation-dissipation theorem (FDT) directly at lattice level: this gives correct fluctuations for mass and momentum densities, and for stresses, at all wavevectors $k$. Unlike previous work, which recovers FDT only as $k\\to 0...

Adhikari, R.; Cates, M. E.; Stratford, K.; Wagner, A. J.

2004-01-01

337

Establishing solar water disinfection as a water treatment method at household level  

Directory of Open Access Journals (Sweden)

Full Text Available 1.1 billion People worldwide do not have access to safe drinking water and therefore are exposed to a high risk for diarrhoeal diseases. As a consequence, about 6,000 children die each day of dehydration due to diarrhoea. Adequate water treatment methods and safe storage of drinking water, combined with hygiene promotion, are required to prevent the population without access to safe drinking water from illness and death. Solar water disinfection (SODIS is a new water treatment to be applied at household level with a great potential to reduce diarrhoea incidence of users. The method is very simple and the only resources required for its application are transparent PET plastic bottles (or glass bottles and sufficient sunlight: microbiologically contaminated water is filled into the bottles and exposed to the full sunlight for 6 hours. During solar exposure, the diarrhoea causing pathogens are killed by the UV-A radiation of the sunlight. At present, SODIS is used by about 2 Million users in more than 20 countries of the South. Diarrhoea incidence of users significantly has been reduced by 30 to 70 %. A careful and long-term community education process that involves creating awareness on the importance of treating drinking water and initiates behaviour change is required to establish the sustainable practice of SODIS at community level. In Madagascar, more than 160 children younger than 5 years die each day from malaria, diarrhoea and acute respiratory illnesses. The application of household water treatment methods such as SODIS significantly could contribute to improve their health.

Regula Meierhofer

2006-12-01

338

Design of double-fuzzy-integral intelligent water level controller for steam generator  

International Nuclear Information System (INIS)

In order to effectively control the water level of steam generator, a double-fuzzy-integral water level controller is designed in this paper. A 'false water level' distinguishing fuzzy controller is added before normal fuzzy controller, to control the water level effectively when SG is in 'false water level' phase. In order to have an optimal water level control, this paper gives the result of fuzzy controller and integral controller export in phase. By the analyzing of control curve, it has validated that the designed double-fuzzy-integral water level controller may overcome the disadvantageous influence given by 'false water level' phenomena to the water level control, and that the control excess adjustment quantity is small and the steady time is short. (authors)

339

Bode Analysis and Modeling of Water Level Change in the Great Lakes  

Science.gov (United States)

Power Spectral Density calculated from a fast Fourier transform expresses a time series in terms of power in the corresponding frequency domain. The power-scaling exponent ( ? ) is determined by fitting a power function to a log-log plot of frequency ( f ) or period ( 1/f ) versus power in the frequency domain. Anthropogenic and natural fluctuations including precipitation, runoff, snowmelt, water retention time, evaporation, and outflow all contribute to changes in water levels recorded in the Great Lakes. In this study, NOAA verified hourly water level data ranging from 20 to 30 years in duration for five stations in Lake Michigan and four stations in Lake Superior were analyzed. Water level time series in the Great Lakes are found to exhibit power law scaling and are thus self-affine over four distinct period ranges, each with a different beta value. With this information, a model of the original time series may be generated using an approach which draws from concepts in control theory and feedback systems. Bode Analysis can be applied in the frequency domain to explain variations in the scaling behavior ( ? ) of water level data by examining the patterns of change in amplitude and phase across frequencies. A Bode magnitude plot of the system is created from the data of power versus frequency converting the amplitude to 20log dB magnitude. A transfer function representing the output of the system divided by the input is then derived based on the data using Laplace transforms and solved for magnitude and phase. Bode analysis results in a series of two transfer function equations, one for magnitude and one for phase, for each distinct beta value over the specified period range. The type of differential equation controls the slope ( ? ) while the constant (k) in the differential equation controls the position (period) of transitions in scaling behavior (i.e., corner frequencies or inflection points) and are characteristics of the system. Combining the transfer functions for all frequencies yields a Frequency Response Model of the underlying internal dynamics of the system and provides a basis to determine how a system will respond to any given input. For water level change in the Great Lakes, the complex pattern of scaling versus period can be well approximated by a combination of linear differential equations or transfer functions representing magnitude and phase at each frequency within each period range. The linear differential equation Frequency Response Model describes water levels of the Great Lakes system as two spring inertial systems coupled together and provides a quantitative measure of variations observed in the Power Spectral Density plots. The Frequency Response Model is also used to generate a synthetic time series which is statistically identical to the original Great Lakes water level time series. This method introduces a novel way to generate a quantitative, equation-based model of self-affine time series data.

Tebbens, S. F.; Smigelski, J. R.; Barton, C. C.

2009-12-01

340

Comparative Analysis of Seepage Losses From Nighttime Water Level Changes and Water Balance Methods  

Science.gov (United States)

Several techniques including Darcy's theory of one and two dimensional groundwater flow, seepage meters, and water balance have been used in the past to estimate seepage from impoundments such as reservoirs, ponds, and constructed wetlands. These methods result in varying level of errors in seepage estimates depending on method and biogeophysical setting to which they are applied. In this study, we explore a simple yet effective method of estimating groundwater fluxes for two stormwater impoundments (SIs) and a partially drained wetland located in agricultural areas using diurnal changes in surface water levels inside these systems. Days with no inflow, outflow, and rainfall were selected to minimize the effect of the error associated water balance components on seepage estimation. Difference in water levels between 20:00 hrs and 5:00 hrs was calculated for the selected days. Only nighttime change was considered keeping in mind the fact that evapotranspiration is negligible during night and hence, the change in water levels can be attributed to seepage alone. Seepage from the analysis of night-time change in the water levels was compared to the estimates from the water balance method with seepage being the residual component of the balance. Results show that seepage constitutes a large part of total outflow from the impoundments (29% and 17% for SI1 during 2008-2009 and 2009-2010 respectively, 30% for SI2 during 2009-2010 and seepage was greater than the total surface water outflow from SI2 during 2010-2011). Accuracy of this method varied from 5% to 41% for first and 4% to 29% for the second SI. Considering that errors as high as 100% have been reported with the use of Darcy's approach, the errors from our method are lower. The lower errors combined with ease of application without using the hydraulic conductivity values makes our approach feasible for other similar systems. Improved seepage estimate from the proposed method will result in quantification of nutrient fluxes from SI through subsurface pathways, which is likely to result in a more realistic representation of treatment efficiency of these impoundments. For instance, phosphorus treatment efficiency of SI1 for 2008-2009 was estimated to be -17% and -60% with and without seepage consideration, respectively. Key words: Groundwater flux, impoundment, wetland, water balance, Phosphorus, treatment efficiency.

Shukla, A.; Shukla, S.; Wu, C.

2013-12-01

341

Paleoecology of a Northern Michigan Lake and the relationship among climate, vegetation, and Great Lakes water levels  

Science.gov (United States)

We reconstructed Holocene water-level and vegetation dynamics based on pollen and plant macrofossils from a coastal lake in Upper Michigan. Our primary objective was to test the hypothesis that major fluctuations in Great Lakes water levels resulted in part from climatic changes. We also used our data to provide temporal constraints to the mid-Holocene dry period in Upper Michigan. From 9600 to 8600 cal yr B.P. a shallow, lacustrine environment characterized the Mud Lake basin. A Sphagnum-dominated wetland occupied the basin during the mid-Holocene dry period (???8600 to 6600 cal yr B.P.). The basin flooded at 6600 cal yr B.P. as a result of rising water levels associated with the onset of the Nipissing I phase of ancestral Lake Superior. This flooding event occured contemporaneously with a well-documented regional expansion of Tsuga. Betula pollen increased during the Nipissing II phase (4500 cal yr B.P.). Macrofossil evidence from Mud Lake suggests that Betula alleghaniensis expansion was primarily responsible for the rising Betula pollen percentages. Major regional and local vegetational changes were associated with all the major Holocene highstands of the western Great Lakes (Nipissing I, Nipissing II, and Algoma). Traditional interpretations of Great Lakes water-level history should be revised to include a major role of climate. ?? 2002 University of Washington.

Booth, R.K.; Jackson, S.T.; Thompson, T.A.

2002-01-01

342

Ion Chromatographic Determination of low level Perchlorate in Natural Waters  

International Nuclear Information System (INIS)

Perchlorate (ClO4-) is a persistent contaminant of drinking-, surface-, and ground-water, and of soils. Possible contributions of ClO4- contamination are the military, the space program, and supporting industries and fertilizers. Perchlorate has long been known to have a negative effect on the thyroid gland. It has been added to the United States Environmental Protection Agency's (EPA) Contaminant candidate List (CCL) in 1998, so that ClO4 can be regulated at a concentration safe to humans. This paper describes the determination of trace level ClO4- in various matrices utilizing ion chromatographic method. The method utilizes a Dionex IonPac AS11 column with suppressed conductivity detection, 1500ul sample loop, and a 100 mN NaOH eluent at a flow rate of 1.0ml/min. These parameters allow a method detection limit (MDL) of 0.277ug/1 and a short retention time of 8 minutes. A quality control, proficiency testing samples from the EPA and a number of environmental samples from New York State (ground water) and California (ground and surface waters) were analyzed by this technique. Concentrations measured were in the range of 1.9-217 ug/1. No evidence of ClO4- was found in various commonly used fertilizers. (author)

343

Investigation of natural radioactivity levels in water around Kadugli, Sudan  

Energy Technology Data Exchange (ETDEWEB)

Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for {sup 238}U, {sup 226}Ra, {sup 222}Rn, and {sup 232}Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: <1.0-7.5, 8.5-16.5, <1.6, and <0.1-0.39 mBq L{sup -1} for {sup 238}U, {sup 226}Ra, {sup 222}Rn, and {sup 232}Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, <0.1-39 mBq L{sup -1}) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr{sup -1} except in one groundwater sample with an associated dose of 0.7 mSv yr{sup -1}.

Osman, Alfatih A.A. [Sudan Atomic Energy Commission, P.O. Box 3001, Khartoum (Sudan)], E-mail: alfatih_123@yahoo.com; Salih, Isam; Shaddad, Ibrahim A.; El Din, Saif; Siddeeg, M.B.; Eltayeb, Hatem; Idriss, Hajo; Hamza, Walid; Yousif, E.H. [Sudan Atomic Energy Commission, P.O. Box 3001, Khartoum (Sudan)

2008-11-15

344

CFNN based water level control for nuclear steam generator  

International Nuclear Information System (INIS)

Because normal PID controller can't change its parameters according to the change of control object parameters. In this paper, the compensatory fuzzy neural network (CFNN) was used with a simplified model of nuclear steam generator (NSG) to design a NSG water level controller. Compensatory neurons which were introduced in the CFNN will make the control system improve the quality of fault tolerant and more stable. Meanwhile compensative fuzzy computation is optimized dynamically in the study algorithm of neural network, therefore the network is much more adaptive and the training speed is much faster. The results of simulation show that under this control method the system has smaller maximum overshoot and faster convergence speed than that of under normal PID control method. The CFNN can not only adjust parameters properly on line, but also can optimized relevant fuzzy reasoning in dynamic way, so it suit to be used on ling learning and control. The control method used in this paper is meaningful to the research of NSG water level intelligent control. (authors)

345

Multi-bed regenerative adsorption chiller - improving the utilization of waste heat and reducing the chilled water outlet temperature fluctuation  

Energy Technology Data Exchange (ETDEWEB)

A multi-bed regenerative adsorption chiller design is proposed. The concept aims to extract the most enthalpy from the low-grade waste heat before it is purged into the drain. It is also able to minimise the chilled water temperature fluctuation so that downstream temperature smoothing device may be downsized or even eliminated in applications where tighter temperature control may be required. The design also avoids a master-and-slave configuration so that materials invested are not under-utilised. Because of the nature of low-grade waste heat utilisation, the performance of adsorption chillers is measured in terms of the recovery efficiency, {eta} instead of the conventional COP. For the same waste heat source flowrate and inlet temperature, a four-bed chiller generates 70% more cooling capacity than a typical two-bed chiller. A six-bed chiller in turn generates 40% more than that of a four-bed chiller. Since the beds can be triggered into operation sequentially during start-up, the risk of ice formation in the evaporator during start-up is greatly reduced compared with that of a two-bed chiller. (Author)

Chua, H.T. [National Univ. of Singapore, Faculty of Engineering, Singapore (Singapore); Ng, K.C. [National Univ. of Singapore, Dept. of Mechanical and Production Engineering, Singapore (Singapore); Malek, A. [National Univ. of Singapore, Singapore (Singapore); Kashiwagi, T.; Akisawa, A.; Saha, B.B. [Tokyo Univ. of Agriculture and Technology, Dept. of Mechanical Systems Engineering, Tokyo (Japan)

2001-07-01

346

Ground-water withdrawals, water-level changes, land-surface subsidence, and ground-water quality in Fort Bend County, Texas, 1969-87  

Science.gov (United States)

Fort Bend County, Texas, one of the fastest growing counties in the U.S., is dependent entirely on groundwater for public supply. Withdrawals for public supply increased from 4 Mgal/d (million gallons per day) in 1969 to 28 Mgal/d in 1986. Total withdrawals increased from 56 Mgal/day in 1969 to 72 Mgal/day in 1982, but decreased because of reductions in irrigation withdrawals, to 53 Mgal/d in 1986. The net decline in the potentiometric surfaces from 1969 to 1987 ranged from less than 4 ft in the upper unit and 100 ft in the lower unit of the Chicot aquifer to 125 ft in the Evangeline aquifer. The northeastern part of the county is most susceptible to land-surface subsidence. From 1969-87, chloride concentrations differed by less than 15 mg/L. The median concentrations of dissolved solids were 475 mg/L in the upper unit of the Chicot, 337 mg/L in the lower unit, and 307 mg/L in the Evangeline. Between 1968-69 and 1987, water levels in wells in the upper unit of the Chicot generally fluctuated less than 4 ft and declined in wells in the lower unit of the Chicot from less than 10 ft in most of western Fort Bend County to 100 ft in the northeast. Hydrographs of wells completed in the lower unit of the Chicot showed that water levels continued to decline from 1969 to the early 1980's. The hydrographs of wells located outside of the northeast area generally show a stabilization of water levels after 1982, corresponding to the reductions in withdrawals in the county and neighboring Houston metropolitan area. Withdrawals from the Evangeline aquifer increased from 15% of the total withdrawals in 1969 to 50% in 1986. Water-level declines in wells screened in the Evangeline aquifer during 1969-86 ranged from less than 25 ft in northwestern Fort Bend County to 125 ft in the northeast. In the southwestern one-fourth of the county, decline was less than 50 ft. (USGS)

Locke, G.L.

1990-01-01

347

Glassy Interfacial Dynamics of Ni Nanoparticles: Part II Discrete Breathers as an Explanation of Two-Level Energy Fluctuations  

OpenAIRE

Recent studies of the dynamics of diverse condensed amorphous materials have indicated significant heterogeneity in the local mobility and a progressive increase in collective particle motion upon cooling that takes the form of string-like particle rearrangements. In a previous paper (Part I), we examined the possibility that fluctuations in potential energy E and particle mobility ? associated with this ‘dynamic heterogeneity’ might offer information about the scale of collective motion...

Zhang, Hao; Douglas, Jack F.

2012-01-01

348

Compilation of ground-water level measurements, obtained by the United States Geological Survey in Puerto Rico, 1958-1985  

Science.gov (United States)

A digital compilation of the groundwater levels in Puerto Rico was prepared as part of the Caribbean Islands Regional Aquifers System Analysis program. Of special interest are the groundwater levels measurements obtained on a routine basis at wells located in the different aquifer regions or aquifer zones. Data from 181 observation wells were entered in the computer data base. The data base includes the following: name, latitude and longitude coordinates, owner, diameter, depth, station identification, local number, aquifer area or region, period of record, construction date, earliest groundwater level reported, and groundwater level fluctuations for various time periods between 1958 and 1985. Data showing conditions under which groundwater level measurements may have been affected by (1) pumping of the well, (2) by a nearby pumping well (3) a specific method by which the groundwater level was determined, (4) whether the well was recently pumped, and (5) when recorded, the lowest water level are also indicated. The summarized information is available in printed format on a yearly basis as part of the Water Resources Data Publication series. (USGS)

Torres-Gonzalez, Sigfredo

1991-01-01

349

Simulated and measured water levels and estimated water-level changes in the Albuquerque area, central New Mexico, 1950-2012  

Science.gov (United States)

The City of Albuquerque, the major population center in New Mexico, underwent a more than fivefold population increase between 1950 and 2010. Before 2009, groundwater was the primary source of the City of Albuquerque’s municipal water supply, but since that time, the city has diverted water through the San Juan-Chama Drinking Water Project to augment municipal water supplies. Consequently, there is interest in understanding how groundwater levels changed in response to groundwater pumping, surface-water diversions, and conservation measures. To give a more detailed history of water-level changes from 1950 through 2012, the U.S. Geological Survey, in cooperation with the Albuquerque Bernalillo County Water Utility Authority, created maps showing water-level contours and changes by contouring water-table elevations and production-zone hydraulic heads that were simulated with a recently updated regional-scale transient groundwater-flow model at 10-year intervals from 1950 to 2000

Rice, Steven E.; Oelsner, Gretchen P.; Heywood, Charles E.

2014-01-01

350

Non Invasive Water Level Monitoring on Boiling Water Reactors Using Internal Gamma Radiation: Application of Soft Computing Methods  

International Nuclear Information System (INIS)

To provide best knowledge about safety-related water level values in boiling water reactors (BWR) is essentially for operational regime. For the water level determination hydrostatic level measurement systems are almost exclusively applied, because they stand the test over many decades in conventional and nuclear power plants (NPP). Due to the steam generation especially in BWR a specific phenomenon occurs which leads to a water-steam mixture level in the reactor annular space and reactor plenum. The mixture level is a high transient non-measurable value concerning the hydrostatic water level measuring system and it significantly differs from the measured collapsed water level. In particular, during operational and accidental transient processes like fast negative pressure transients, the monitoring of these water levels is very important. In addition to the hydrostatic water level measurement system a diverse water level measurement system for BWR should be used. A real physical diversity is given by gamma radiation distribution inside and outside the reactor pressure vessel correlating with the water level. The vertical gamma radiation distribution depends on the water level, but it is also a function of the neutron flux and the coolant recirculation pump speed. For the water level monitoring, special algorithms are required. An analytical determination of the gamma radiation distribution outside the reactor pressure vessel is impossible due to the multitude of radiis impossible due to the multitude of radiation of physical processes, complicated non-stationary radiation source distribution and complex geometry of fixtures. For creating suited algorithms Soft Computing methods (Fuzzy Sets Theory, Artificial Neural Networks, etc.) will be used. Therefore, a database containing input values (gamma radiation distribution) and output values (water levels) had to be built. Here, the database was established by experiments (data from BWR and from a test setup) and simulation with the authorised thermo-fluid code ATHLET. (authors)

351

Radioactive levels in Taihu and water bodies of Suzhou  

International Nuclear Information System (INIS)

The radioactive levels in Taihu and water bidies of Suzhou, southern China, were investigated in 1983. The results of the investigation were compared with that of 1973. In addition, the authors investigated a suspectable radioactive pollutant-ash of coal powder from Wongting coal-fired power plant and its affect on the water in Taihu and Suzhou section of the Grand Canal. These results show: the average radioactive levels in Taihu are 41.4 mBq/L for total ?, 91.9 mBq/L for total ?, 3.4 x 10-7 g/L for uranium, 3.5 x 10-7 g/L for thorium; in Suzhou section of the Grand Canal 37.6 mBq/L for total ?, 101.9 mBq/L for total ?, 3.6 x 10-7 g/L for uranium, 4.9 x 10-7 g/L for thorium; in shallow well of Suzhou 61.4 mBq/L for total ?, 857.7 mBq/L for total ?, 1.6 x 10-7 g/L for uranium, 3.9 x 10-7 g/L for thorium. The radioactive levels in dry season are higher than that in rainy season, and each of them is lower than that in 1973. The average radioactive levels in Taihu and in Suzhou section of the Grand Canal caused by ash of coal powder from Wongting coal-fired power plant are: 87.3 and 140.6 mBq/L for total ? respectively; 146.3 and 162.8 mBq/L for total ?; 162.0 and 130.2 mBq/L for 40K; 6.7 x 10-7 and 5.3 x 10-7 g/L for uranium and 4.1 x 10-7 and 4.6 x 10-7 g/L for thorium

352

Emergency action levels for light water reactors. Draft report  

International Nuclear Information System (INIS)

United States nuclear power plants are currently preparing revised radiological emergency response plans. As part of these plans, each licensee is establishing plant-specific instrumentation readings, called emergency action levels (EALs), that indicate the presence of a problem and the need to declare one of four classes of emergency as designated by the U.S. Nuclear Regulatory Commission. In this report, the EALs prepared for a pressurized water reactor and a boiling water reactor are assessed to determine whether they meet the requirements of NUREG-0654, Rev. 1 Appendix 1. In addition, five recent nuclear incidents are studied to determine how their outcomes might have been affected by the new emergency response plans. Most of the EALs reviewed were judged adequate. In some cases, alternate EALs or sets of generic EALs are proposed to meet the intent of NUREG-0654 Rev 1 Appendix 1, and the wording of some of the initiating conditions for the four emergency classes is clarified. For three of the five incidents reviewed, the new emergency response plans probably would not have affected the outcome; in one case, the plans would probably have prevented core damage; and any effect on the outcome of the last incident is uncertain

353

Trend Analysis of Ground-Water Levels and Spring Discharge in the Yucca Mountain Region, Nevada and California, 1960-2000  

International Nuclear Information System (INIS)

Ground-water level and discharge data from 1960 to 2000 were analyzed for the Yucca Mountain region of southern Nevada and eastern California. Included were water-level data from 37 wells and a fissure (Devils Hole) and discharge data from five springs and from a flowing well. Data were evaluated for variability and for upward, downward, or cyclic trends with an emphasis on the period 1992-2000. Potential factors causing trends in water levels and discharge include ground-water withdrawal, infiltration of precipitation, earthquakes, evapotranspiration, barometric pressure, and earth tides. Statistically significant trends in ground water levels or spring discharge from 1992 to 2000 were upward at 12 water-level sites and downward at 14 water-level sites and 1 spring-discharge site. In general, the magnitude of the change in water level from 1992 to 2000 was small (less than 2 feet), except where influenced by pumping or local effects such as possible equilibration from well construction or diversion of nearby surface water. Seasonal trends are superimposed on some of the long-term (1992-2000) trends in water levels and discharge. Factors causing seasonal trends include barometric pressure, evapotranspiration, and pumping. The magnitude of seasonal change in water level can vary from as little as 0.05 foot in regional aquifers to greater than 5 feet in monitoring wells near large supply wells in the Amargosa Farms area. Three major episodes of earthquake activity affecajor episodes of earthquake activity affected water levels in wells in the Yucca Mountain region between 1992 and 2000: the Landers/Little Skull Mountain, Northridge, and Hector Mine earthquakes. The Landers/Little Skull Mountain earthquakes, in June 1992, had the largest observed effect on water levels and on discharge during the study period. Monthly measurements of wells in the study network show that earthquakes affected water levels from a few tenths of a foot to 3.5 feet. In the Ash Meadows area, water levels remained relatively stable from 1992 to 2000, with some water levels showing small rising trends and some declining slightly. Possible reasons for water-level fluctuations at sites AD-6 (Tracer Well 3), AM-5 (Devils Hole Well), and AM-4 (Devils Hole) from 1960 to 2000 include climate change, local and regional ground-water withdrawals, and tectonic activity. In Jackass Flats, water levels from 1992 to 2000 in six wells adjacent to Fortymile Wash displayed either small upward trends or no upward or downward trend. Comparison of trends in water levels from 1983 to 2000 for these six wells shows good correlations between all wells and suggests a common mechanism controlling water levels in the area. Of the likely controls on the system-precipitation or pumping in Jackass Flats-precipitation appears to be the predominant factor controlling water levels near Fortymile Wash. Water levels in the heavily pumped Amargosa Farms area declined from about 10 to 30 feet from 1964 to 2000. Water-level declines accelerated beginning in the early 1990's as pumping rates increased substantially. Pumping in the Amargosa Farms area may affect water levels in some wells as far away as 5-14 miles. The water level at site DV-3 (Travertine Point 1 Well) and discharge at site DV-2 (Navel Spring), both in the Death Valley hydrographic area, had downward trends from 1992 to 2000. The cause of these downward trends may be linked to earthquakes, pumping in the Amargosa Farms area, or both

354

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...  

Science.gov (United States)

...2010-10-01 2010-10-01 false Water-level indicators, water columns, gauge-glass...Requirements § 52.01-110 Water-level indicators, water columns, gauge-glass...modifies PG-60). (a) Boiler water level devices. Boiler water level...

2010-10-01

355

Late Pleistocene and Early Holocene lake-level fluctuations in the Lahontan Basin, Nevada: Implications for the distribution of archaeological sites  

Science.gov (United States)

The Great Basin of the western U.S. contains a rich record of late Pleistocene and Holocene lake-level fluctuations as well as an extensive record of human occupation during the same time frame. We compare spatial-temporal relationships between these records in the Lahontan basin to consider whether lake-level fluctuations across the Pleistocene-Holocene transition controlled distribution of archaeological sites. We use the reasonably well-dated archaeological record from caves and rockshelters as well as results from new pedestrian surveys to investigate this problem. Although lake levels probably reached maximum elevations of about 1230-1235 m in the different subbasins of Lahontan during the Younger Dryas (YD) period, the duration that the lakes occupied the highest levels was brief Paleoindian and early Archaic archaeological sites are concentrated on somewhat lower and slightly younger shorelines (???1220-1225 in) that also date from the Younger Dryas period. This study suggests that Paleoindians often concentrated their activities adjacent to large lakes and wetland resources soon after they first entered the Great Basin. ?? 2008 Wiley Periodicals, Inc.

Adams, K.D.; Goebel, T.; Graf, K.; Smith, G.M.; Camp, A.J.; Briggs, R.W.; Rhode, D.

2008-01-01

356

Behaviors of extreme water level in the Pearl River Delta and possible impacts from human activities  

OpenAIRE

Trends and variations of the extreme water levels defined as exceeding/falling below certain thresholds (mean ± std) across the Pearl River Delta (PRD) are systematically explored using the linear regression method. Research results indicate that: 1) The upper PRD is dominated by the significant decreasing low water level, and significant increasing low water level can be identified in the lower PRD. The variations of the relative frequency of the high water level are characterized...

Chen, Y. D.; Zhang, Q.; Yang, T.; Xu, C.; Chen, X.; Jiang, T.

2007-01-01

357

GPS water level measurements for Indonesia's Tsunami Early Warning System  

Directory of Open Access Journals (Sweden)

Full Text Available On Boxing Day 2004, a severe tsunami was generated by a strong earthquake in Northern Sumatra causing a large number of casualties. At this time, neither an offshore buoy network was in place to measure tsunami waves, nor a system to disseminate tsunami warnings to local governmental entities. Since then, buoys have been developed by Indonesia and Germany, complemented by NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART buoys, and have been moored offshore Sumatra and Java. The suite of sensors for offshore tsunami detection in Indonesia has been advanced by adding GPS technology for water level measurements.

The usage of GPS buoys in tsunami warning systems is a relatively new approach. The concept of the German Indonesian Tsunami Early Warning System (GITEWS (Rudloff et al., 2009 combines GPS technology and ocean bottom pressure (OBP measurements. Especially for near-field installations where the seismic noise may deteriorate the OBP data, GPS-derived sea level heights provide additional information.

The GPS buoy technology is precise enough to detect medium to large tsunamis of amplitudes larger than 10 cm. The analysis presented here suggests that for about 68% of the time, tsunamis larger than 5 cm may be detectable.

T. Schöne

2011-03-01

358

Ground-water monitoring at Santa Barbara, California; Phase 2, Effects of pumping on water levels and on water quality in the Santa Barbara ground-water basin  

Science.gov (United States)

From July 1978 to January 1980, water levels in the southern part of the Santa Barbara ground-water basin declined more than 100 feet. These water-level declines resulted from increases in municipal pumping since July 1978. The increase in municipal pumping was part of a basin-testing program designed to determine the usable quantity of ground water in storage. The pumping, centered in the city less than 1 mile from the coast, has caused water-level declines to altitudes below sea level in the main water-bearing zones. As a result, the ground-water basin would be subject to saltwater intrusion if the study-period pumpage were maintained or increased. Data indicate that saltwater intrusion has degraded the quality of the water yielded from six coastal wells. During the study period, the six coastal wells all yielded water with chloride concentrations in excess of 250 milligrams per liter, and four of the wells yielded water with chloride concentrations in excess of 1,000 milligrams per liter. Previous investigators believed that saltwater intrusion was limited to the shallow part of the aquifer, directly adjacent to the coast. The possibility of saltwater intrusion into the deeper water-bearing deposits in the aquifer was thought to be remote because an offshore fault truncates these deeper deposits so that they lie against consolidated rocks on the seaward side of the fault. Results of this study indicate, however, that ocean water has intruded the deeper water-bearing deposits, and to a much greater extent than in the shallow part of the aquifer. Apparently the offshore fault is not an effective barrier to saltwater intrusion. No physical barriers are known to exist between the coast and the municipal well field. Therefore, if the pumping rate maintained during the basin-testing program were continued, the degraded water along the coast could move inland and contaminate the municipal supply wells. The time required for the degraded water to move from the coast to the nearest supply well is estimated, using Darcy's equation, to be about 20 years. Management alternatives for controlling saltwater intrusion in the Santa Barbara area include (1) decreasing municipal pumping, (2) increasing the quantity of water available for recharge by releasing surplus water from surface reservoirs to Mission Creek, (3) artificially recharging the basin using injection wells, and (4) locating municipal supply wells farther from the coast and spacing them farther apart in order to minimize drawdown. Continued monitoring of water levels and water quality would enable assessment of the effectiveness of the control measures employed.

Martin, Peter

1984-01-01

359

Drinking cholera : salinity levels and palatability of drinking water in coastal Bangladesh  

DEFF Research Database (Denmark)

OBJECTIVES: To measure the salinity levels of common water sources in coastal Bangladesh and explore perceptions of water palatability among the local population to investigate the plausibility of linking cholera outbreaks in Bangladesh with ingestion of saline-rich cholera-infected river water. METHODS: Hundred participants took part in a taste-testing experiment of water with varying levels of salinity. Salinity measurements were taken of both drinking and non-drinking water sources. Informal group discussions were conducted to gain an in-depth understanding of water sources and water uses. RESULTS: Salinity levels of non-drinking water sources suggest that the conditions for Vibrio cholerae survival exist 7-8 days within the local aquatic environment. However, 96% of participants in the taste-testing experiment reported that they would never drink water with salinity levels that would be conducive to V. cholerae survival. Furthermore, salinity levels of participant's drinking water sources were all well below the levels required for optimal survival of V. cholerae. Respondents explained that they preferred less salty and more aesthetically pleasing drinking water. CONCLUSION: Theoretically, V. cholerae can survive in the river systems in Bangladesh; however, water sources which have been contaminated with river water are avoided as potential drinking water sources. Furthermore, there are no physical connecting points between the river system and drinking water sources among the study population, indicating that the primary driver for cholera cases in Bangladesh is likely not through the contamination of saline-rich river water into drinking water sources.

Grant, Stephen Lawrence; Tamason, Charlotte Crim

2015-01-01

360

Water Hardness Level and ItAND#8217;s Health Effects  

OpenAIRE

Water hardness is a term used to define the number of ions contained in the water, especially quantity sulphate, carbonate salts of calcium and magnesium. This characteristis of water is a important quality in it’s use as drinking water, industrial water and service water. The temporary hardness level of water cames from bicarbonate salts of calcium and magnesium whereas chloride, sulphate, nitrate, phosphate, silicate salts of calcium and magnesium. In order to indicate the hardness le...

Necmettin Kocak; Mahir Gulec; Omer Faruk Tekbas

2011-01-01

361

To save water or not? : A study of water scarcity at multiple levels, and people's attitudestowards it in Bangalore, India  

OpenAIRE

In a situation where population growth and development is to be sustained throughnaturally limited water resources, something needs to be done to either render waterusage more effective or make more water available. This is the situation in Bangalore Urban District (BUD), an ever growing city lying far from perennial water sources. This thesis presents the water situation in BUD, and aims to analyze the current status of water resources on multiple levels in BUD. Further the aim is to look at...

Bogna?s, De?sire?e

2011-01-01

362

Behaviors of extreme water level in the Pearl River Delta and possible impacts from human activities  

Directory of Open Access Journals (Sweden)

Full Text Available Trends and variations of the extreme water levels defined as exceeding/falling below certain thresholds (mean ± std across the Pearl River Delta (PRD are systematically explored using the linear regression method. Research results indicate that: 1 The upper PRD is dominated by the significant decreasing low water level, and significant increasing low water level can be identified in the lower PRD. The variations of the relative frequency of the high water level are characterized by the decreasing variability in the middle PRD. However more stations show significant changes of the relative frequency of the low water level across the PRD. No confirmative changing patterns of the relative frequency of the low water level can be detected in the middle PRD; 2 When it comes to the seasonal variations of the high/low water level in JJA (high flow periods in the PRD, stations located closer to the estuary tend to exhibit increasing high/low water level. However stations located closer to the upper PRD tend to show decreasing high/low water level. Similar patterns can be identified in the high/low water level in DJF (low flow periods in the PRD; 3 The changes of the water level in the PRD are heavily affected by human interferences, e.g. in-channel dredging, sand mining and the construction of levees. The stations dominated by decreasing water level are mostly located along the river channels featured by highly-intensive dredging. The stations along the coastal regions show significant increasing extreme high/low water level. The coastal regions are not influenced by in-channel dredging, and furthermore, sediment loads from upper and middle PRD are deposited in the river mouths and which will tend to raise the water level in the estuary of the PRD. The findings of this paper may be helpful for local water resource management.

Y. D. Chen

2007-12-01

363

Holocene palaeoclimate and sea level fluctuation recorded from the coastal Barker Swamp, Rottnest Island, south-western Western Australia  

Science.gov (United States)

The Holocene palaeoclimatic history of south-western Western Australia (SWWA) has received little attention compared to south-eastern Australia, and this has resulted in conflicting views over the impact of climate variability in the region. We present here a well-dated, high-resolution record from two overlapping sediment cores obtained from the centre of Barker Swamp, Rottnest Island, offshore Perth. The records span the last 8.7 ka, with the main lacustrine phase occurring after 7.4 ka. This site preserves both pollen and several ostracod taxa. The pollen record suggests a long-term shift from the early-mid Holocene to the late Holocene to drier conditions with less shrubland and more low-ground cover and less fire activity. A salinity transfer function was developed from ostracod faunal assemblage data and trace metal ratios (Mg/Ca, Sr/Ca and Na/Ca) and stable isotopes (?18O and ?13C) analysed on selected ostracod valves. These provide a detailed history of evaporation/precipitation (E/P) differences that clearly shows that the SWWA region was subjected to significant climatic shifts over the last 7.4 ka, with a broad shift towards increased aridity after 5 ka. The swamp ranged from fresh to saline as recorded in the ostracod valve chemistry and the independently-derived salinity transfer function. The ostracod record also indicates that a sea-level highstand occurred between ca. 4.5 and 4.3 ka, with probable step-wise increases at 6.75, 6.2, and 5.6 ka, with the last vestiges of salt water intrusion at ca. 1 ka. After about 2.3 ka, the fresh, groundwater lens that underlies the western portion of the island intersected the swamp depression, influencing the hydrology of the swamp. The broad climatic changes recorded in Barker Swamp are also compared with data from southern South Africa, and it is suggested that the Southern Annular Mode appears to have been the dominant driver in the climate of these regions and that the Indian Ocean Dipole is of little importance in the southern regions of the south-western Cape of Africa and south-western Western Australia.

Gouramanis, C.; Dodson, J.; Wilkins, D.; De Deckker, P.; Chase, B. M.

2012-10-01

364

Loss of pressurizer water level during station blackout  

International Nuclear Information System (INIS)

Station blackout is the loss of all alternating current (ac) power to both the essential and nonessential electrical buses in a nuclear power plant. The US Nuclear Regulatory Commission (NRC) has proposed a requirement that all plants be capable of maintaining adequate core cooling during station blackout events lasting a specified duration. The NRC has also suggested acceptable specified durations of four or eight hours, depending on individual plant susceptibility to blackout events. In a pressurized water reactor (PWR), the occurrence of a station blackout event results in the functional loss of many plant components, including main feedwater, reactor coolant pumps, the emergency core cooling system, and pressurizer heaters and spray. Nevertheless, PWRs have the capability of removing decay heat for some period of time using steam-driven auxiliary feedwater pumps and the natural-circulation capability of the primary system. The purpose of this investigation is to determine the early response of a PWR to station blackout conditions. In particular, the effect of primary coolant shrinkage and inventory loss on pressurizer level is examined to gain insight into the operational and analytical issues associated with the proposed station blackout coping requirement

365

Fuzzy logic control of steam generator water level in pressurized water reactors  

International Nuclear Information System (INIS)

In this paper a fuzzy logic controller is applied to control the steam generator water level in a pressurized water reactor. The method does not require a detailed mathematical mode of the object to be controlled. The design is based on a set of linguistic rules that were adopted from the human operator's experience. After off-line fuzzy computation, the controller is a lookup table, and thus, real-time control is achieved. Shrink-and-swell phenomena are considered in the linguistic rules, and the simulation results show that their effect is dramatically reduced. The performance of the control system can also be improved by changing the input and output scaling factors, which is convenient for on-line tuning

366

Wake fluctuations  

International Nuclear Information System (INIS)

Under many conditions of importance in experiment, fluctuations in the wake of a leading ion in condensed matter are relatively unimportant compared to fluctuations accompanying direct interaction with the medium. The reason is that the wake of a leading ion is composed in the main of relatively small perturbations of large numbers of electrons. These perturbations may add to yield a large average force but, because they carry small momenta, give rise to rather small fluctuations of the force about its mean value

367

Options for future effective water management in Lombok: A multi-level nested framework  

Science.gov (United States)

Previous research on water use in Lombok identified reduced water available in springs and limits on seasonal water availability. It foreshadowed increasing competition for water resources in critical areas of Lombok. This study examines preliminary information on local social-institutional arrangements for water allocation in the context of Ostrom's rules for self-governing institutions. We identify robust customary mechanisms for decision-making about water sharing and rules at a local level and suggest areas of further investigation for strengthening multi-level networked and nested frameworks, in collaboration with higher levels of government.

Sjah, Taslim; Baldwin, Claudia

2014-11-01

368

Level of Water Awareness at Some Jordanian Universities Studentâ??s  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Jordan has been facing shortage in water sector during the last three decades due to natural and society factors, weakness of water awareness is one of these Society factors, so this study focused on the level of water awareness in fields of; water significant in life, water problem in Jordan, water conservation at part of Jordanian society. Approach: The study aimed to Investigate how some Jordanian Universities students behave to identify the level of water awareness in sectors of water, giving students positive attitudes towards water resources and conservation, uses and reduce consumption. Encourage students for voluntary collective actions as A hope to raising water awareness. The society sample study were represented by (320 Jordanian Universities students, take in consideration the following variables: Academic specialists, sex, University status and average monthly income per family. Data base for previous variables obtained by special questioner prepared for this study. Data run to statistical analysis through some simple Descriptive statistical approaches as (ANOVA. Results: The study showed that the level of water awareness towards water significant at a weak level, it reached to (57% of sample study towards water conservation. Students of scientific specializes have water awareness more than humanitarian specializes. There isnâ??t impact of University status and average monthly income on the level of water awareness. Conclusion/Recommendations: Most of study sample recognized with significant of water at life, they admit that Jordan faced water problem, but female were more than male at the level of water awarenes, also scientific specialists more than humanitarian specialties. Study recommends to enrich the curriculum of humanitarian sciences, with more topics looking for water and encourage personal activities and volunteers work to conserve water and rationalized it, also activation laws and legislation related with water.

Mohamad Said Damanhouri

2012-01-01

369

Records of wells, ground-water levels, and ground-water withdrawals in the lower Goose Creek Basin, Cassia County, Idaho  

Science.gov (United States)

Investigations by the United States Geological Survey of Ground Water in the Southern border area of the Snake Rive Plain, south of the Snake River, a re concerned at the present time with delineation of the principal ground-water districts, the extent and location of existing ground-water developments, the possibilities for additional development, and the effects of ground-water development on the regimen of streams and reservoirs whose waters are appropriate for beneficial use. The lower part of the Goose Creek Basin is one of the important ground-water districts of the southern plains area and there are substantial but spotty developments of ground water for irrigation in the basin. Several thousand irrigable acres that are now dry could be put under irrigation if a dependable supply of ground water could be developed. The relations of the ground-water reservoirs to the regime of the Snake River and Goose Cree, and to the large body of ground water in the Snake River Plain north of the Snake, are poorly known. A large amount of geologic and hydrologic study remains to be done before those relations can be accurately determined. Investigations will be continued in the future but file work and preparation of a comprehensive report inevitably will be delayed. Therefore the available records are presented herein in order to make them accessible to farmers, well drillers, government agencies, and the general public. Interpretation of the records is not attempted in this report and is deferred pending the accumulation of additional and quantitative information. The data summarized herein include records of the locations and physical characteristics of wells, the depth to water in wells, fluctuations of water levels in observation wells, and estimated rates and volumes of seasonal ans yearly ground-water pumpage for irrigation, municipal, and other uses. This information is complete for work done as of December 31, 1952. The investigations upon which this report is based were undertaken in cooperation with the U.S. Bureau of Reclamation, Region I, at the request of the Planning Division, Central Snake River District. The report was complied in the first instance for the use of the Bureau of Reclamation but is now released to the public. The observation-well program in the area has been maintained in cooperation with the Idaho State Department of Reclamation as part of the regular cooperative program of the Geological Survey.

Mower, R.W.

1954-01-01

370

Investigation and inprovement in steam drum water level measurement systems of the RBMK-1000 type NPP  

International Nuclear Information System (INIS)

Improvements which enabled to increase the accuracy and reliability of water level measurement in steam drums (SD) of Kursk, Smolensk and Chernobylsk NPP are described. They include: application of levelling vessels with partially heated constant level chamber removed from SD rooms; use of level indicators; organization of level gauge blowing by feed water. Operation of level gauge under dynamic conditions was analyzed on the basis of solving equations of heat and material balance and equation of motion in steam and water lines. Analysis revealed the peculiarities of their operation under transient conditions and enabled to evaluate level gauge errors for sharp drop of steam pressure in SD

371

Lake Storage Measurements For Water Resources Management: Combining Remotely Sensed Water Levels and Surface Areas  

Science.gov (United States)

Presently operating satellite-based radar altimeters have the ability to monitor variations in surface water height for large lakes and reservoirs, and future sensors will expand observational capabilities to many smaller water bodies. Such remote sensing provides objective, independent information where in situ data are lacking or access is restricted. A USDA/NASA (http://www.pecad.fas.usda.gov/cropexplorer/global_reservoir/) program is performing operational altimetric monitoring of the largest lakes and reservoirs around the world using data from the NASA/CNES, NRL, and ESA missions. Public lake-level products from the Global Reservoir and Lake Monitor (GRLM) are a combination of archived and near real time information. The USDA/FAS utilizes the products for assessing international irrigation potential and for crop production estimates; other end-users study climate trends, observe anthropogenic effects, and/or are are involved in other water resources management and regional water security issues. At the same time, the Dartmouth Flood Observatory (http://floodobservatory.colorado.edu/), its NASA GSFC partners (http://oas.gsfc.nasa.gov/floodmap/home.html), and associated MODIS data and automated processing algorithms are providing public access to a growing GIS record of the Earth's changing surface water extent, including changes related to floods and droughts. The Observatory's web site also provide both archival and near real time information, and is based mainly on the highest spatial resolution (250 m) MODIS bands. Therefore, it is now possible to provide on an international basis reservoir and lake storage change measurements entirely from remote sensing, on a frequently updating basis. The volume change values are based on standard numerical procedures used for many decades for analysis of coeval lake area and height data. We provide first results of this combination, including prototype displays for public access and data retrieval of water storage volume changes. Ground-based data can, in some cases, test the remote sensing accuracy and precision. Data accuracy requirements vary for different applications: reservoir management for flood control, agriculture, or power generation may need more accurate and timely information than (for example) regional assessments of water and food security issues. Thus, the long-term goal for the hydrological sciences community should be to efficiently mesh both types of information and with as extensive geographic coverage as possible.

Brakenridge, G. R.; Birkett, C. M.

2013-12-01

372

Comparison Of Vented And Absolute Pressure Transducers For Water-Level Monitoring In Hanford Site Central Plateau Wells  

International Nuclear Information System (INIS)

Automated water-level data collected using vented pressure transducers deployed in Hanford Site Central Plateau wells commonly display more variability than manual tape measurements in response to barometric pressure fluctuations. To explain this difference, it was hypothesized that vented pressure transducers installed in some wells are subject to barometric pressure effects that reduce water-level measurement accuracy. Vented pressure transducers use a vent tube, which is open to the atmosphere at land surface, to supply air pressure to the transducer housing for barometric compensation so the transducer measurements will represent only the water pressure. When using vented transducers, the assumption is made that the air pressure between land surface and the well bore is in equilibrium. By comparison, absolute pressure transducers directly measure the air pressure within the wellbore. Barometric compensation is achieved by subtracting the well bore air pressure measurement from the total pressure measured by a second transducer submerged in the water. Thus, no assumption of air pressure equilibrium is needed. In this study, water-level measurements were collected from the same Central Plateau wells using both vented and absolute pressure transducers to evaluate the different methods of barometric compensation. Manual tape measurements were also collected to evaluate the transducers. Measurements collected during this study demonstrated that the vented pressure transducers over-responded to barometric pressure fluctuations due to a pressure disequilibrium between the air within the wellbores and the atmosphere at land surface. The disequilibrium is thought to be caused by the relatively long time required for barometric pressure changes to equilibrate between land surface and the deep vadose zone and may be exacerbated by the restriction of air flow between the well bore and the atmosphere due to the presence of sample pump landing plates and well caps. The disequilibrium is likely limited to wells screened across the water table (i.e., open to the deep vadose zone) where the depth to water is large or a low-permeability layer occurs in the vadose zone. Such wells are a pathway for air movement between the deep vadose zone and land surface and this sustains the pressure disequilibrium between the well bore and the atmosphere for longer time periods. Barometric over-response was not observed with the absolute pressure transducers because barometric compensation was achieved by directly measuring the air pressure within the well. Users of vented pressure transducers should be aware of the over-response issue in certain Hanford Site wells and ascertain if it will affect the use of the data. Pressure disequilibrium between the well and the atmosphere can be identified by substantial air movement through the wellbore. In wells exhibiting pressure disequilibrium, it is recommended that absolute pressure transducers be used rather than vented transducers for applications that require precise automated determinations of well water-level changes in response to barometric pressure fluctuations.

373

COMPARISON OF VENTED AND ABSOLUTE PRESSURE TRANSDUCERS FOR WATER-LEVEL MONITORING IN HANFORD SITE CENTRAL PLATEAU WELLS  

Energy Technology Data Exchange (ETDEWEB)

Automated water-level data collected using vented pressure transducers deployed in Hanford Site Central Plateau wells commonly display more variability than manual tape measurements in response to barometric pressure fluctuations. To explain this difference, it was hypothesized that vented pressure transducers installed in some wells are subject to barometric pressure effects that reduce water-level measurement accuracy. Vented pressure transducers use a vent tube, which is open to the atmosphere at land surface, to supply air pressure to the transducer housing for barometric compensation so the transducer measurements will represent only the water pressure. When using vented transducers, the assumption is made that the air pressure between land surface and the well bore is in equilibrium. By