Science.gov

Sample records for floating water bridge

  1. A floating water bridge produces water with excess charge

    NASA Astrophysics Data System (ADS)

    Fuchs, Elmar C.; Sammer, Martina; Wexler, Adam D.; Kuntke, Philipp; Woisetschläger, Jakob

    2016-03-01

    Excess positive and negative Bjerrum-defect like charge (protonic and ‘aterprotonic’, from ancient Greek ἄ'τɛρ, ‘without’) in anolyte and catholyte of high voltage electrolysis of highly pure water was found during the so-called ‘floating water bridge’ experiment. The floating water bridge is a special case of an electrohydrodynamic liquid bridge and constitutes an intriguing phenomenon that occurs when a high potential difference (~kV cm-1) is applied between two beakers of water. To obtain such results impedance spectroscopy was used. This measurement technique allows the depiction and simulation of complex aqueous systems as simple electric circuits. In the present work we show that there is an additional small contribution from the difference in conductivity between anolyte and catholyte which cannot be measured with a conductivity meter, but is clearly visible in an impedance spectrum.

  2. Experimental investigation of the stability of the floating water bridge.

    PubMed

    Montazeri Namin, Reza; Azizpour Lindi, Shiva; Amjadi, Ahmad; Jafari, Nima; Irajizad, Peyman

    2013-09-01

    When a high voltage is applied between two beakers filled with deionized water, a floating bridge of water is formed in between exceeding the length of 2 cm when the beakers are pulled apart. Currently two theories regarding the stability of the floating water bridge exist, one suggesting that the tension caused by electric field in the dielectric medium is holding the bridge and the other suggesting surface tension to be responsible for the vertical equilibrium. We construct experiments in which the electric field and the geometry of the bridge are measured and compared with predictions of theories of the floating water bridge stability. We use a numerical simulation for estimation of the electric field. Our results indicate that the two forces of dielectric and surface tensions hold the bridge against gravity simultaneously and, having the same order of magnitude, neither of the two forces are negligible. In bridges with larger diameters, the effect of dielectric tension is slightly more in the vertical equilibrium than surface tension. Results show that the stability can be explained by macroscopic forces, regardless of the microscopic changes in the water structure.

  3. Proton production, neutralisation and reduction in a floating water bridge

    NASA Astrophysics Data System (ADS)

    Sammer, Martina; Wexler, Adam D.; Kuntke, Philipp; Wiltsche, Helmar; Stanulewicz, Natalia; Lankmayr, Ernst; Woisetschläger, Jakob; Fuchs, Elmar C.

    2015-10-01

    This work reports on proton production, transport, reduction and neutralization in floating aqueous bridges under the application of a high dc voltage (‘floating water bridge’). Recently possible mechanisms for proton transfer through the bridge were suggested. In this work we visualize and describe the production of protons in the anolyte and their neutralization in the catholyte. Apart from that, protons are reduced to hydrogen due to electrolysis. Microbubbles are detached instantly, due to the electrohydrodynamic flow at the electrode surface. No larger, visible bubbles are formed and the system degasses through the bridge due to its higher local temperature. A detailed analysis of trace elements originating from beaker material, anode or the atmosphere is presented, showing that their influence on the overall conduction compared to the contribution of protons is negligible. Finally, an electrochemical rationale of high voltage electrolysis of low ionic strength solutions is presented.

  4. Structure of the floating water bridge and water in an electric field

    PubMed Central

    Skinner, Lawrie B.; Benmore, Chris J.; Shyam, Badri; Weber, J. K. R.; Parise, John B.

    2012-01-01

    The floating water bridge phenomenon is a freestanding rope-shaped connection of pure liquid water, formed under the influence of a high potential difference (approximately 15 kV). Several recent spectroscopic, optical, and neutron scattering studies have suggested that the origin of the bridge is associated with the formation of anisotropic chains of water molecules in the liquid. In this work, high energy X-ray diffraction experiments have been performed on a series of floating water bridges as a function of applied voltage, bridge length, and position within the bridge. The two-dimensional X-ray scattering data showed no direction-dependence, indicating that the bulk water molecules do not exhibit any significant preferred orientation along the electric field. The only structural changes observed were those due to heating, and these effects were found to be the same as for bulk water. These X-ray scattering measurements are supported by molecular dynamics (MD) simulations which were performed under electric fields of 106 V/m and 109 V/m. Directional structure factor calculations were made from these simulations parallel and perpendicular to the E-field. The 106 V/m model showed no significant directional-dependence (anisotropy) in the structure factors. The 109 V/m model however, contained molecules aligned by the E-field, and had significant structural anisotropy. PMID:23010930

  5. Protonic charge defect structures in floating water bridges observed as Zundel and Eigen solvation arrangements

    NASA Astrophysics Data System (ADS)

    Teschke, Omar; de Castro, Jose Roberto; Valente Filho, Juracyr Ferraz; Soares, David Mendez

    2017-10-01

    Protonic arrangements were detected in water bridge structures using confocal Raman microscopy, and the spectra show two formed structures. The measured Raman spectra were modified using the voltage applied to the bridge structure, which changed the proportion of these two species. Initially, for a 6.3 kV applied voltage, there was a measurable increase in the bridge current above the Ohmic contribution and the observed Raman spectrum of this new injected specie corresponded to the computed spectrum for the Zundel protonic arrangement. As the voltage further increases a contribution from the Eigen proton solvation specie is added to the measured spectrum.

  6. Copper ion fluxes through the floating water bridge under strong electric potential.

    PubMed

    Giuliani, Livio; D'Emilia, Enrico; Lisi, Antonella; Grimaldi, Settimio; Brizhik, Larissa; Del Giudice, Emilio

    2015-01-01

    We have performed a series of experiments applying high voltage between two electrodes, immersed in two beakers containing bidistilled water in a way similar to experiments conducted by Fuchs and collaborators, which showed that a water bridge can be formed between the two containers. We also observed the formation of water bridge. Moreover, choosing different pairs of electrodes depending on the material they are made up of, we observed that copper ions flow can pass along the bridge if the negative electrode is made up of copper. We show that the direction of the flux not only depends on the applied electrostatic field but on the relative electronegativity of the electrodes too. These results open new perspectives in understanding the properties of water. We suggest a possible explanation of the obtained results.

  7. Floating and flying ferrofluid bridges induced by external magnetic fields

    NASA Astrophysics Data System (ADS)

    Ma, Rongchao; Zhou, Yixin; Liu, Jing

    2015-04-01

    A ferrofluid is a mixture that exhibits both magnetism and fluidity. This merit enables the ferrofluid to be used in a wide variety of areas. Here we show that a floating ferrofluid bridge can be induced between two separated boards under a balanced external magnetic field generated by two magnets, while a flying ferrofluid bridge can be induced under an unbalanced external magnetic field generated by only one magnet. The mechanisms of the ferrofluid bridges were discussed and the corresponding mathematical equations were also established to describe the interacting magnetic force between the ferro particles inside the ferrofluid. This work answered a basic question that, except for the well-known floating water bridges that are related to electricity, one can also build up a liquid bridge that is related to magnetism.

  8. 8. CAR FLOAT AND TUG DOCKED AT BRIDGE NO. 11 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. CAR FLOAT AND TUG DOCKED AT BRIDGE NO. 11 FROM BRIDGE NO. 9 APRON. LOOKING SOUTHEAST. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

  9. 77 FR 73541 - Safety Zone: Gilmerton Bridge Center Span Float-in, Elizabeth River; Norfolk, Portsmouth, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ... [Docket No. USCG-2012-0642] RIN 1625-AA00 Safety Zone: Gilmerton Bridge Center Span Float-in, Elizabeth... safety of life on navigable waters during the Gilmerton Bridge Center Span Float- in and bridge... safety zone in the Gilmerton Bridge Area (77 FR 43557) on September 5-9, 2012. We received no comments on...

  10. 63. VIEW OF THE SHOOFLY BRIDGE LIFT SPAN BEING FLOATED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    63. VIEW OF THE SHOOFLY BRIDGE LIFT SPAN BEING FLOATED INTO PLACE, LOOKING NORTH, January 29, 1935 - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

  11. 40. VAL CONNECTING BRIDGE AND BARGES FLOATING ON RESERVOIR (PREVIOUSLY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. VAL CONNECTING BRIDGE AND BARGES FLOATING ON RESERVOIR (PREVIOUSLY SUPPORTED MUZZLE END OF LAUNCHER BRIDGE). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  12. 77 FR 43557 - Safety Zone; Gilmerton Bridge Center Span Float-in, Elizabeth River; Norfolk, Portsmouth, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-25

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Gilmerton Bridge Center Span Float-in... provide for the safety of life on navigable waters during the Gilmerton Bridge Center Span Float- in and bridge construction of span placement. This action is intended to restrict vessel traffic movement to...

  13. 77 FR 35900 - Safety Zone; Gilmerton Bridge Center Span Float-in, Elizabeth River; Norfolk, Portsmouth, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-15

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Gilmerton Bridge Center Span Float-in... provide for the safety of life on navigable waters during the Gilmerton Bridge Center Span Float- in and bridge construction of span placement. This action is intended to restrict vessel traffic movement to...

  14. View from floating barracks west of lift bridge to reserve ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View from floating barracks west of lift bridge to reserve basin on psny. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Reserve Basin & Marine Railway, League Island, Philadelphia, Philadelphia County, PA

  15. 66. VAL BRIDGE AND BARGES FLOATING FROM ISLIP CANYON TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    66. VAL BRIDGE AND BARGES FLOATING FROM ISLIP CANYON TO THE VAL SITE, April 12, 1948. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  16. 77 FR 44544 - Safety Zone; Gilmerton Bridge Center Span Float-In, Elizabeth River; Norfolk, Portsmouth, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-30

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Gilmerton Bridge Center Span Float-In...; withdrawal. SUMMARY: The Coast Guard is withdrawing its proposed rule concerning the Gilmerton Bridge Center Span Float-in and bridge construction of span placement. The original proposal had a start date of July...

  17. Water-Pressure Distribution on Seaplane Float

    NASA Technical Reports Server (NTRS)

    Thompson, F L

    1929-01-01

    The investigation presented in this report was conducted for the purpose of determining the distribution and magnitude of water pressures likely to be experienced on seaplane hulls in service. It consisted of the development and construction of apparatus for recording water pressures lasting one one-hundredth second or longer and of flight tests to determine the water pressures on a UO-1 seaplane float under various conditions of taxiing, taking off, and landing. The apparatus developed was found to operate with satisfactory accuracy and is suitable for flight tests on other seaplanes. The tests on the UO-1 showed that maximum pressures of about 6.5 pounds per square inch occur at the step for the full width of the float bottom. Proceeding forward from the step the maximum pressures decrease in magnitude uniformly toward the bow, and the region of highest pressures narrows toward the keel. Immediately abaft the step the maximum pressures are very small, but increase in magnitude toward the stern and there once reached a value of about 5 pounds per square inch. (author)

  18. 77 FR 75016 - Safety Zone: Gilmerton Bridge Center Span Float-in, Elizabeth River; Norfolk, Portsmouth, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-19

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone: Gilmerton Bridge Center Span Float-in... Federal Register an interim temporary final rule establishing a safety zone around the Gilmerton Bridge... around the Gilmerton Bridge center span barge (77 FR 73541). Inadvertently, this rule included an error...

  19. 26. Mechanical float gages used to monitor level of water ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. Mechanical float gages used to monitor level of water in the filtration bed reservoir. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

  20. Collective Behavior of Camphor Floats Migrating on the Water Surface

    NASA Astrophysics Data System (ADS)

    Nishimori, Hiraku; Suematsu, Nobuhiko J.; Nakata, Satoshi

    2017-10-01

    As simple and easily controllable objects among various self-propelled particles, camphor floats on the water surface have been widely recognized. In this paper, we introduce characteristic behaviors and discuss the background mechanism of camphor floats on water, both in isolated and non-isolated conditions. In particular, we focus on: (i) the transition of dynamical characters through bifurcations exhibited by systems with small number of camphor floats and (ii) the emergence of a rich variety of complex dynamics observed in systems with large number camphor floats, and attempt to elucidate these phenomena through mathematical modeling as well as experimental analysis. Finally, we discuss the connection of the dynamics of camphor floats to that of a wider class of complex and sophisticated dynamics exhibited by various types of self-propelled particles.

  1. 16. EAST ELEVATION OF FLOAT HOUSE AND FISH WATER RELEASE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. EAST ELEVATION OF FLOAT HOUSE AND FISH WATER RELEASE OUTLET. PART OF ENERGY DISSIPATING BAFFLE PIER SYSTEM IS VISIBLE AT LEFT. - Pit 4 Diversion Dam, Pit River west of State Highway 89, Big Bend, Shasta County, CA

  2. Hadfield watches a water bubble float in the Node 1

    NASA Image and Video Library

    2013-01-21

    View of Canadian Space Agency (CSA) Chris Hadfield,Expedition 34 Flight Engineer (FE),watching a water bubble float freely,showing his image refracted,in the Node 1. Photo was taken during Expedition 34.

  3. Ford watches a water bubble float in the Node 1

    NASA Image and Video Library

    2013-01-21

    ISS034-E-031855 (21 Jan. 2013) --- NASA astronaut Kevin Ford, Expedition 34 commander, watches a water bubble float freely between him and the camera, showing his image refracted, in the Unity node of the International Space Station.

  4. Water over the bridge

    USGS Publications Warehouse

    Piatt, John F.

    1995-01-01

    The March-April issue of American Scientist contains a commentary by Julia K. Parrish and P. Dee Boersma (Macroscope, "Muddy Waters") that purports to "assess the validity of the claims made concerning seabird mortality as a result of the [Exxon Valdez oil] spill." Parrish and Boersma would have us believe that estimates of seabird mortality made in 1990 by myself and colleagues were exaggerated and that later upward revisions of those estimates were unwarranted. Their assessment, however, is seriously flawed.

  5. Water rolling and floating upon water: marbles supported by a water/marble interface.

    PubMed

    Bormashenko, Edward; Bormashenko, Yelena; Musin, Albina

    2009-05-01

    Floating of liquid marbles on a water/air interface was studied. The critical density allowing floating marbles containing NaCl solution was established experimentally and compared with its calculated value. A satisfactory agreement between experimental and theoretical values of the critical density is reported.

  6. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS COMMERCIAL AIR TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over water beyond the shoreline must...

  7. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS COMMERCIAL AIR TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over water beyond the shoreline must...

  8. Finescale Water-Mass Variability from ARGO Profiling Floats

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Finescale Water -Mass Variability from ARGO Profiling...assessment of water -mass (aka thermohaline or spice) variability as a measure of stirring along isopycnals, as well as density ratio Rρ statistics, from the...global ARGO profiling float data set. APPROACH For the water -mass analysis, the profile data is transformed onto σθ density coordinates

  9. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... emergency ditching, if— (1) It is a single-engine helicopter; or (2) It is a multi-engine helicopter that... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Helicopter floats for over water. 136.11... TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter...

  10. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... emergency ditching, if— (1) It is a single-engine helicopter; or (2) It is a multi-engine helicopter that... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Helicopter floats for over water. 136.11... TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter...

  11. Theory of water and charged liquid bridges.

    PubMed

    Morawetz, K

    2012-08-01

    The phenomenon of liquid bridge formation due to an applied electric field is investigated. A solution of a charged catenary is presented, which allows one to determine the static and dynamical stability conditions where charged liquid bridges are possible. The creeping height, the bridge radius and length, as well as the shape of the bridge are calculated showing an asymmetric profile, in agreement with observations. The flow profile is calculated from the Navier-Stokes equation leading to a mean velocity, which combines charge transport with neutral mass flow and which describes recent experiments on water bridges.

  12. Potential of water surface-floating microalgae for biodiesel production: Floating-biomass and lipid productivities.

    PubMed

    Muto, Masaki; Nojima, Daisuke; Yue, Liang; Kanehara, Hideyuki; Naruse, Hideaki; Ujiro, Asuka; Yoshino, Tomoko; Matsunaga, Tadashi; Tanaka, Tsuyoshi

    2017-03-01

    Microalgae have been accepted as a promising feedstock for biodiesel production owing to their capability of converting solar energy into lipids through photosynthesis. However, the high capital and operating costs, and high energy consumption, are hampering commercialization of microalgal biodiesel. In this study, the surface-floating microalga, strain AVFF007 (tentatively identified as Botryosphaerella sudetica), which naturally forms a biofilm on surfaces, was characterized for use in biodiesel production. The biofilm could be conveniently harvested from the surface of the water by adsorbing onto a polyethylene film. The lipid productivity of strain AVFF007 was 46.3 mg/L/day, allowing direct comparison to lipid productivities of other microalgal species. The moisture content of the surface-floating biomass was 86.0 ± 1.2%, which was much lower than that of the biomass harvested using centrifugation. These results reveal the potential of this surface-floating microalgal species as a biodiesel producer, employing a novel biomass harvesting and dewatering strategy.

  13. Water flow and solute transport in floating fen root mats

    NASA Astrophysics Data System (ADS)

    Stofberg, Sija F.; EATM van der Zee, Sjoerd

    2015-04-01

    Floating fens are valuable wetlands, found in North-Western Europe, that are formed by floating root mats when old turf ponds are colonized by plants. These terrestrialization ecosystems are known for their biodiversity and the presence of rare plant species, and the root mats reveal different vegetation zones at a small scale. The vegetation zones are a result of strong gradients in abiotic conditions, including groundwater dynamics, nutrients and pH. To prevent irreversible drought effects such as land subsidence and mineralization of peat, water management involves import of water from elsewhere to maintain constant surface water levels. Imported water may have elevated levels of salinity during dry summers, and salt exposure may threaten the vegetation. To assess the risk of exposure of the rare plant species to salinity, the hydrology of such root mats must be understood. Physical properties of root mats have scarcely been investigated. We have measured soil characteristics, hydraulic conductivity, vertical root mat movement and groundwater dynamics in a floating root mat in the nature reserve Nieuwkoopse Plassen, in the Netherlands. The root mat mostly consists of roots and organic material, in which the soil has a high saturated water content, and strongly varies in its stage of decomposition. We have found a distinct negative correlation between degree of decomposition and hydraulic conductivity, similar to observations for bogs in the literature. Our results show that the relatively young, thin edge of the root mat that colonizes the surface water has a high hydraulic conductivity and floats in the surface water, resulting in very small groundwater fluctuations within the root mat. The older part of the root mat, that is connected to the deeper peat layers is hydrologically more isolated and the material has a lower conductivity. Here, the groundwater fluctuates strongly with atmospheric forcing. The zones of hydraulic properties and vegetation, appear to

  14. Halogen-water-hydrogen bridges in biomolecules.

    PubMed

    Zhou, Peng; Lv, Jing; Zou, Jianwei; Tian, Feifei; Shang, Zhicai

    2010-02-01

    The importance of water in biological systems has long been recognized in chemistry and biology communities. In this article we describe a new manner by which water affects biomolecular behaviors, called halogen-water-hydrogen bridge (XWH bridge), that is, one hydrogen bonding (H-bonding) in water-mediated H-bond bridge is replaced by halogen bonding (X-bonding). Although behaving similarly to water-mediated H-bond motif, the XWH bridge usually stands in multifurcated forms and possesses stronger directionality. Quantum mechanical analysis on several model and real systems reveals that the XWH bridges are more thermodynamically stable than other water-involved interactions, and this stability is further enhanced by the cooperation of X-bonding and H-bonding. Crystal structure survey clearly demonstrates the significance of XWH bridges in stabilization of biomolecular conformations and in mediation of protein-protein, protein-nucleic acid, and receptor-ligand recognition and binding. These findings shed light into the potential value of XWH bridges in drug design and biological engineering.

  15. Apparatus for removing oil and other floating contaminants from a moving body of water

    DOEpatents

    Strohecker, J.W.

    1973-12-18

    The patent describes a process in which floating contaminants such as oil and solid debris are removed from a moving body of water by employing a skimming system which uses the natural gravitational flow of the water. A boom diagonally positioned across the body of water diverts the floating contaminants over a floating weir and into a retention pond where an underflow weir is used to return contaminant-free water to the moving body of water. The floating weir is ballasted to maintain the contaminant-receiving opening therein slightly below the surface of the water during fluctuations in the water level for skimming the contaminants with minimal water removal.

  16. Water Pressure Distribution on a Twin-Float Seaplane

    NASA Technical Reports Server (NTRS)

    Thompson, F L

    1930-01-01

    This is the second of a series of investigations to determine water pressure distribution on various types of seaplane floats and hulls, and was conducted on a twin-float seaplane. It consisted of measuring water pressures and accelerations on a TS-1 seaplane during numerous landing and taxiing maneuvers at various speeds and angles. The results show that water pressures as great as 10 lbs. per sq. in.may occur at the step in various maneuvers and that pressures of approximately the same magnitude occur at the stern and near the bow in hard pancake landings with the stern way down. At the other parts of the float the pressures are less and are usually zero or slightly negative for some distance abaft the step. A maximum negative pressure of 0.87 lb. Per square inch was measured immediately abaft the step. The maximum positive pressures have a duration of approximately one-twentieth to one-hundredth second at any given location and are distributed over a very limited area at any particular instant.

  17. Floating Probe Assembly for Measuring Temperature of Water

    NASA Technical Reports Server (NTRS)

    Stewart, Randy; Ruffin, Clyde

    2002-01-01

    A floating apparatus denoted a temperature probe aquatic suspension system (TPASS) has been developed for measuring the temperature of an ocean, lake, or other natural body of water at predetermined depths. Prior instruments built for the same purpose were found to give inaccurate readings because the apparatuses themselves significantly affected the temperatures of the water in their vicinities. The design of the TPASS is intended to satisfy a requirement to minimize the perturbation of the temperatures to be measured. The TPASS includes a square-cross-section aluminum rod 28 in. (=71 cm) long with floats attached at both ends. Each float includes five polystyrene foam disks about 3/4 in.(=1.9 cm) thick and 2.5 in. (=6.4 cm) in diameter. The disks are stacked to form cylinders, bolted to the rod, and covered with hollow plastic sleeves. A metal sleeve is clamped to the middle of the aluminum rod, from whence it hangs down into the water. Temperature probes (which can be thermocouples, thermistors, or resistance temperature devices) are placed within the sleeve at the desired measurement depths. Wires from the temperature probes are routed to the input terminals of a data logger.

  18. Floating Probe Assembly for Measuring Temperature of Water

    NASA Technical Reports Server (NTRS)

    Selinsky, T.; Stewart, Randy; Ruffin, Clyde

    2002-01-01

    A floating apparatus denoted a temperature probe aquatic suspension system (TPASS) has been developed for measuring the temperature of an ocean, lake, or other natural body of water at predetermined depths. Prior instruments built for the same purpose were found to give inaccurate readings because the apparatuses themselves significantly affected the temperatures of the water in their vicinities. The design of the TPASS is intended to satisfy a requirement to minimize the perturbation of the temperatures to be measured. The TPASS includes a square-cross-section aluminum rod 28 in. (approx. = 71 cm) long with floats attached at both ends. Each float includes five polystyrene foam disks about 3/4 in. (approx. = 1.9 cm) thick and 2.5 in. (approx. = 6.4 cm) in diameter. The disks are stacked to form cylinders, bolted to the rod, and covered with hollow plastic sleeves. A metal sleeve is clamped to the middle of the aluminum rod, from whence it hangs down into the water. Temperature probes (which can be thermocouples, thermistors, or resistance temperature devices) are placed within the sleeve at the desired measurement depths. Wires from the temperature probes are routed to the input terminals of a data logger. This work was done by Randy

  19. Floating Probe Assembly for Measuring Temperature of Water

    NASA Technical Reports Server (NTRS)

    Selinsky, T.; Stewart, Randy; Ruffin, Clyde

    2002-01-01

    A floating apparatus denoted a temperature probe aquatic suspension system (TPASS) has been developed for measuring the temperature of an ocean, lake, or other natural body of water at predetermined depths. Prior instruments built for the same purpose were found to give inaccurate readings because the apparatuses themselves significantly affected the temperatures of the water in their vicinities. The design of the TPASS is intended to satisfy a requirement to minimize the perturbation of the temperatures to be measured. The TPASS includes a square-cross-section aluminum rod 28 in. (approx. = 71 cm) long with floats attached at both ends. Each float includes five polystyrene foam disks about 3/4 in. (approx. = 1.9 cm) thick and 2.5 in. (approx. = 6.4 cm) in diameter. The disks are stacked to form cylinders, bolted to the rod, and covered with hollow plastic sleeves. A metal sleeve is clamped to the middle of the aluminum rod, from whence it hangs down into the water. Temperature probes (which can be thermocouples, thermistors, or resistance temperature devices) are placed within the sleeve at the desired measurement depths. Wires from the temperature probes are routed to the input terminals of a data logger. This work was done by Randy

  20. Floating Probe Assembly for Measuring Temperature of Water

    NASA Technical Reports Server (NTRS)

    Stewart, Randy; Ruffin, Clyde

    2002-01-01

    A floating apparatus denoted a temperature probe aquatic suspension system (TPASS) has been developed for measuring the temperature of an ocean, lake, or other natural body of water at predetermined depths. Prior instruments built for the same purpose were found to give inaccurate readings because the apparatuses themselves significantly affected the temperatures of the water in their vicinities. The design of the TPASS is intended to satisfy a requirement to minimize the perturbation of the temperatures to be measured. The TPASS includes a square-cross-section aluminum rod 28 in. (=71 cm) long with floats attached at both ends. Each float includes five polystyrene foam disks about 3/4 in.(=1.9 cm) thick and 2.5 in. (=6.4 cm) in diameter. The disks are stacked to form cylinders, bolted to the rod, and covered with hollow plastic sleeves. A metal sleeve is clamped to the middle of the aluminum rod, from whence it hangs down into the water. Temperature probes (which can be thermocouples, thermistors, or resistance temperature devices) are placed within the sleeve at the desired measurement depths. Wires from the temperature probes are routed to the input terminals of a data logger.

  1. Floating Probe Assembly for Measuring Temperature of Water

    NASA Technical Reports Server (NTRS)

    Stewart, Randy; Ruffin, Clyde

    2003-01-01

    A floating apparatus denoted a temperature probe aquatic suspension system (TPASS) has been developed for measuring the temperature of an ocean, lake, or other natural body of water at predetermined depths. These types of measurements are used in computer models to relate remotely sensed water-surface temperature to bulkwater temperature. Prior instruments built for the same purpose were found to give inaccurate readings because the apparatuses themselves significantly affected the temperatures of the water in their vicinities. The design of the TPASS is intended to satisfy a requirement to minimize the perturbation of the temperatures to be measured.

  2. Performance of floating oil booms in unsheltered waters

    NASA Astrophysics Data System (ADS)

    Iglesias, Gregorio; Castro, Alberte

    2013-04-01

    Oil booms are a fundamental tool to diminish the impact of an oil spill. They tend to perform reasonably well in sheltered waters, e.g. within a harbour. However, their performance is often inadequate in open water conditions, under waves, winds and currents. And it is precisely in those conditions that they are needed if oil slicks are to be prevented from reaching certain particularly sensitive areas, such as estuaries, rias, etc. (Castro et al., 2010; Iglesias et al., 2010). In this work the performance of floating oil booms under waves and currents is assessed on the basis of laboratory experiments carried out in a state-of-the-art wave-current flume. Different oil boom models are used, representative of booms with long and short skirts and with different weights. The results show that different booms behave very differently under waves and currents, hence the importance of selecting the boom design that is appropriate for the actual conditions under which it will have to contain the oil slick. Thus, different oil booms should be used for different areas. References A. Castro, G. Iglesias, R. Carballo, J.A. Fraguela, 2010. Floating boom performance under waves and currents, Journal of Hazardous Materials 174, 226-235 G. Iglesias, A.Castro, J.A.Fraguela, 2010. Artificial intelligence applied to floating boom behavior under waves and currents, Ocean Engineering 37, 1513-1521.

  3. Floating Marine Debris in waters of the Mexican Central Pacific.

    PubMed

    Díaz-Torres, Evelyn R; Ortega-Ortiz, Christian D; Silva-Iñiguez, Lidia; Nene-Preciado, Alejandro; Orozco, Ernesto Torres

    2017-02-15

    The presence of marine debris has been reported recently in several oceans basins; there is very little information available for Mexican Pacific coasts, however. This research examined the composition, possible sources, distribution, and density of Floating Marine Debris (FMD) during nine research surveys conducted during 2010-2012 in the Mexican Central Pacific (MCP). Of 1820 floating objects recorded, 80% were plastic items. Sources of FMD were determined using key objects, which indicated that the most were related to the presence of the industrial harbor and of a growing fishing industry in the study area. Densities were relatively high, ranging from 40 to 2440objects/km(2); the highest densities were recorded in autumn. FMD were distributed near coastal regions, mainly in Jalisco, influenced by river outflow and surface currents. Our results seem to follow worldwide trends and highlight the need for further studies on potential ecological impacts within coastal waters of the MCP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Particle bridging between oil and water interfaces.

    PubMed

    Xu, Hui; Lask, Mauricio; Kirkwood, John; Fuller, Gerald

    2007-04-24

    Particle bridging between a water drop and a flat oil-water interface has been observed when the drop is brought into contact with the interface, leading to the formation of a dense particle monolayer of disc shape (namely, particle disc) that prevents the drop from coalescing into the bulk water phase. Unlike previous observations where particles from opposite interfaces appear to register with each other before bridging, the present experiment demonstrates that the particle registry is not a necessity for bridging. In many cases, the particles from one of the interfaces were repelled away from the contact region, leaving behind the particles from the other interface to bridge the two interfaces. This is confirmed by particle bridging experiments between two interfaces covered with different sized particles, and between a particle-covered interface and a clean interface. The dynamics associated with the growth of the particle disc due to particle bridging follows a power law relationship between the radius of the disc and time: r proportional, variant t0.32+/-0.03. A scaling analysis assuming capillary attraction as the driving force and a hydrodynamic resistance leads to the power law r proportional, variant t1/3, in good agreement with the experiment. In addition, we found that binary mixtures of two different sized particles can undergo phase segregation driven by the particle bridging process.

  5. Photo-active float for field water disinfection.

    PubMed

    Shwetharani, R; Balakrishna, R Geetha

    2016-03-01

    The present study investigates the antibacterial activity of a photoactive float fabricated with visible light active N-F-TiO2 for the disinfection of field water widely contaminated with Gram positive and Gram negative bacteria like, Salmonella typhimurium (Gram negative), Escherichia coli (Gram negative), Staphylococcus aureus (Gram positive), Bacillus species (Gram positive), and Pseudomonas species (Gram negative). The antibacterial activity can be attributed to the unique properties of the photocatalyst, which releases reactive oxygen species in aqueous solution, under the illumination of sunlight. N-F-TiO2 nanoparticles efficiently photocatalyse the destruction of all the bacteria present in the contaminated water, giving clean water. The inactivation of bacteria is confirmed by a standard plate count method, MDA, RNA and DNA analysis. The purity of water was further validated by SPC indicating nil counts of bacteria after two days of storing and testing. The photocatalysts were characterized by XRD, BET measurement, SEM, EDX, UV-Vis and PL analysis.

  6. Bridge over Troubled Water: Guidance Crosses

    ERIC Educational Resources Information Center

    Amundson, Norm

    2008-01-01

    This article is based on a keynote presentation at an international conference where the focus was cross-over career guidance. Simon and Garfunkel's popular song, "Bridge over troubled water", was used as a metaphor for exploring the cross-over theme. Some of the concepts under consideration included the working alliance, the importance of a…

  7. A study on multi-body floating system in finite water depth by separate region method

    SciTech Connect

    Inoue, Yoshiyuki; Zhang, Xuangang

    1996-12-31

    The research on multi-body floating system has been carried out by many researchers in recent days because of its increased practical uses. In these researches, almost all, three-dimensional source method is applied. In this paper, a relatively simple but effective method, separated region method, is applied for predicting the responses of multi-floating bodies in finite water depth. For a floating rectangular section in the finite water depth, the separated region method (eigenvalue method) is very useful to predict the hydrodynamic forces on the body. The method has been extended here, so as to apply to the problems of multi-floating bodies. To check the validity of the method, motion responses of two floating bodies were calculated and the results were compared with experimental data carried out by M. Ohkusu (1976) and M. Kubo et al. (1989). The agreements between the theoretical and the experimental results of motions of two floating bodies are fairly good.

  8. Tasman Leakage of intermediate waters as inferred from Argo floats

    NASA Astrophysics Data System (ADS)

    Rosell-Fieschi, Miquel; Rintoul, Stephen R.; Gourrion, Jeröme; Pelegrí, Josep L.

    2013-10-01

    use Argo float trajectories to infer ocean current velocity at the sea surface and 1000 dbar near Australia. The East Australian Current flows southward along the east coast of Australia at both surface and intermediate levels, but only the intermediate waters leak round the southern tip of Tasmania and cross the Great Australian Bight. We calculate the transport of Antarctic Intermediate Water (AAIW) between the southern Australian coast and the Antarctic Circumpolar Current (ACC) as the velocity at 1000 dbar times the layer thickness. Between March 2006 and December 2012, the Eulerian AAIW transport through 147°E ranges between 0 and 12.0 sverdrup (Sv). The mean Tasman Leakage of intermediate waters from the Pacific Ocean into the Indian Ocean, obtained using all Argo data until March 2013, is 3.8 ± 1.3 Sv. The mean intermediate water transport into the Indian Ocean through 115°E increases to 5.2 ± 1.8 Sv due to contributions from the westward recirculation of ACC waters.

  9. 3D flexible water channel: stretchability of nanoscale water bridge

    NASA Astrophysics Data System (ADS)

    Chen, Jige; Wang, Chunlei; Wei, Ning; Wan, Rongzheng; Gao, Yi

    2016-03-01

    Artificial water channels can contribute to a better understanding of natural water channels and offer a highly selective, advanced conductance system. Most studies use nanotubes, however it is difficult to fabricate a flexible structure, and the nanosized diameter brings nanoconfinement effects, and nanotube toxicity arouses biosafety concerns. In this paper, we use an electric field to restrain the water molecules to form a nanoscale water bridge as an artificial water channel to connect a separated solid plate by molecular dynamics simulations. We observe strong 3D flexible stretchability in the water bridge, maintaining a variable length and an arbitrary angle for a considerably long time. The stretching of the water bridge enables it to be polarized at an arbitrary angle and the stretchability is linearly dependent upon the polarization strength. More interestingly, we show the possibility of establishing complex water networks, e.g., triangle, rectangle, hexagon, and tetrahedron-tetrahedron water networks. Our results may help realize structurally flexible and environmentally friendly water channels for lab-on-a-chip applications in nanofluidics.Artificial water channels can contribute to a better understanding of natural water channels and offer a highly selective, advanced conductance system. Most studies use nanotubes, however it is difficult to fabricate a flexible structure, and the nanosized diameter brings nanoconfinement effects, and nanotube toxicity arouses biosafety concerns. In this paper, we use an electric field to restrain the water molecules to form a nanoscale water bridge as an artificial water channel to connect a separated solid plate by molecular dynamics simulations. We observe strong 3D flexible stretchability in the water bridge, maintaining a variable length and an arbitrary angle for a considerably long time. The stretching of the water bridge enables it to be polarized at an arbitrary angle and the stretchability is linearly

  10. Salmonid-egg floating boxes as bioindication for riverine water quality and stocking success.

    PubMed

    Pander, J; Geist, J

    2010-06-01

    The salmonid-egg floating box provides an easy bioindication tool for an assessment of water quality, as demonstrated here for the reintroduction of Europe's largest salmonid species, the huchen Hucho hucho.

  11. Chiao watches a water bubble float in the SM taken during Expedition 10

    NASA Image and Video Library

    2005-01-15

    ISS010-E-13562 (15 January 2005) --- Astronaut Leroy Chiao, Expedition 10 commander and NASA Space Station science officer, watches a water bubble float between himself and the camera in the Zvezda Service Module, showing his image refracted.

  12. Chiao watches a water bubble float in the SM taken during Expedition 10

    NASA Image and Video Library

    2005-01-15

    ISS010-E-13569 (15 January 2005) --- Astronaut Leroy Chiao, Expedition 10 commander and NASA ISS science officer, watches a water bubble float between him and the camera, showing his image refracted, on the International Space Station (ISS).

  13. Water-Floating Giant Nanosheets from Helical Peptide Pentamers.

    PubMed

    Lee, Jaehun; Choe, Ik Rang; Kim, Nak-Kyoon; Kim, Won-Je; Jang, Hyung-Seok; Lee, Yoon-Sik; Nam, Ki Tae

    2016-09-27

    One of the important challenges in the development of protein-mimetic materials is understanding the sequence-specific assembly behavior and dynamic folding change. Conventional strategies for constructing two-dimensional (2D) nanostructures from peptides have been limited to using β-sheet forming sequences as building blocks due to their natural tendency to form sheet-like aggregations. We have identified a peptide sequence (YFCFY) that can form dimers via a disulfide bridge, fold into a helix, and assemble into macroscopic flat sheets at the air/water interface. Due to the large driving force for 2D assembly and high elastic modulus of the resulting sheet, the peptide assembly induces flattening of the initially round water droplet. Additionally, we found that stabilization of the helix by dimerization is a key determinant for maintaining macroscopic flatness over a few tens of centimeters even with a uniform thickness of <10 nm. Furthermore, the ability to transfer the sheets from a water droplet to another substrate allows for multiple stacking of 2D peptide nanostructures, suggesting possible applications in biomimetic catalysis, biosensors, and 2D related electronic devices.

  14. Water-Floating Giant Nanosheets from Helical Peptide Pentamers

    NASA Astrophysics Data System (ADS)

    Lee, Jaehun; Nam, Ki Tae

    One of the important challenges in the development of protein-mimetic materials is to understand the sequence specific assembly behavior and the dynamic folding change. Conventional strategies to construct two dimensional nanostructures from the peptides have been limited to beta-sheet forming sequences in use of basic building blocks because of their natural tendency to form sheet like aggregations. Here we identified a new peptide sequence, YFCFY that can form dimers by the disulfide bridge, fold into helix and assemble into macroscopic flat sheet at the air/water interface. Because of large driving force for two dimensional assembly and high elastic modulus of the resulting sheet, the peptide assembly induces the flattening of initially round water droplet. Additionally, we found that stabilization of helix by the dimerization is a key determinant for maintaining macroscopic flatness over a few tens centimeter even with a uniform thickness below 10 nm. Furthermore, the capability to transfer 2D film from water droplet to other substrates allows for the multiple stacking of 2D peptide nanostructure, suggesting possible applications in the biomimetic catalysts, biosensor and 2D related electronic devices. This work was supported by Samsung Research Funding Center of Samsung Electronics under Project Number SRFC-MA1401-01.

  15. Enhancement of Biomass and Lipid Productivities of Water Surface-Floating Microalgae by Chemical Mutagenesis.

    PubMed

    Nojima, Daisuke; Ishizuka, Yuki; Muto, Masaki; Ujiro, Asuka; Kodama, Fumito; Yoshino, Tomoko; Maeda, Yoshiaki; Matsunaga, Tadashi; Tanaka, Tsuyoshi

    2017-05-27

    Water surface-floating microalgae have great potential for biofuel applications due to the ease of the harvesting process, which is one of the most problematic steps in conventional microalgal biofuel production. We have collected promising water surface-floating microalgae and characterized their capacity for biomass and lipid production. In this study, we performed chemical mutagenesis of two water surface-floating microalgae to elevate productivity. Floating microalgal strains AVFF007 and FFG039 (tentatively identified as Botryosphaerella sp. and Chlorococcum sp., respectively) were exposed to ethyl methane sulfonate (EMS) or 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), and pale green mutants (PMs) were obtained. The most promising FFG039 PM formed robust biofilms on the surface of the culture medium, similar to those formed by wild type strains, and it exhibited 1.7-fold and 1.9-fold higher biomass and lipid productivities than those of the wild type. This study indicates that the chemical mutation strategy improves the lipid productivity of water surface-floating microalgae without inhibiting biofilm formation and floating ability.

  16. Enhancement of Biomass and Lipid Productivities of Water Surface-Floating Microalgae by Chemical Mutagenesis

    PubMed Central

    Nojima, Daisuke; Ishizuka, Yuki; Muto, Masaki; Ujiro, Asuka; Kodama, Fumito; Yoshino, Tomoko; Maeda, Yoshiaki; Matsunaga, Tadashi; Tanaka, Tsuyoshi

    2017-01-01

    Water surface-floating microalgae have great potential for biofuel applications due to the ease of the harvesting process, which is one of the most problematic steps in conventional microalgal biofuel production. We have collected promising water surface-floating microalgae and characterized their capacity for biomass and lipid production. In this study, we performed chemical mutagenesis of two water surface-floating microalgae to elevate productivity. Floating microalgal strains AVFF007 and FFG039 (tentatively identified as Botryosphaerella sp. and Chlorococcum sp., respectively) were exposed to ethyl methane sulfonate (EMS) or 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), and pale green mutants (PMs) were obtained. The most promising FFG039 PM formed robust biofilms on the surface of the culture medium, similar to those formed by wild type strains, and it exhibited 1.7-fold and 1.9-fold higher biomass and lipid productivities than those of the wild type. This study indicates that the chemical mutation strategy improves the lipid productivity of water surface-floating microalgae without inhibiting biofilm formation and floating ability. PMID:28555001

  17. A structural homologue of colipase in black mamba venom revealed by NMR floating disulphide bridge analysis.

    PubMed

    Boisbouvier, J; Albrand, J P; Blackledge, M; Jaquinod, M; Schweitz, H; Lazdunski, M; Marion, D

    1998-01-01

    The solution structure of mamba intestinal toxin 1 (MIT1), isolated from Dendroaspis polylepis polylepis venom, has been determined. This molecule is a cysteine-rich polypeptide exhibiting no recognised family membership. Resistance to MIT1 to classical specific endoproteases produced contradictory NMR and biochemical information concerning disulphide-bridge topology. We have used distance restraints allowing ambiguous partners between S atoms in combination with NMR-derived structural information, to correctly determine the disulphide-bridge topology. The resultant solution structure of MIT1, determined to a resolution of 0.5 A, reveals an unexpectedly similar global fold with respect to colipase, a protein involved in fatty acid digestion. Colipase exhibits an analogous resistance to endoprotease activity, indicating for the first time the possible topological origins of this biochemical property. The biochemical and structural homology permitted us to propose a mechanically related digestive function for MIT1 and provides novel information concerning snake venom protein evolution. Copyright 1998 Academic Press.

  18. Diagnosing overturning and water mass transformation in the Labrador Sea from Argo and PALACE floats

    NASA Astrophysics Data System (ADS)

    Holte, J.; Straneo, F.

    2016-02-01

    We use Argo and PALACE floats, which have been sampling the Labrador Sea since the mid 1990s, to examine the Labrador Sea overturning and its variability on seasonal and decadal timescales. Floats have collected observations in all seasons as well as in the boundary current, allowing for an examination of the seasonal signal of the overturning and of the boundary current's contribution to the overturning. We construct seasonal composite geostrophic velocity sections across the mouth of the Labrador Sea from potential density profiles and float trajectories at 1000 m. The velocity sections are used to calculate the horizontal and overturning circulations and the water mass transformation. We also track the seasonal and spatial patterns of properties in the boundary current to evaluate theoretical estimates of sinking in the boundary current. The recent Argo observations, collected during a period of relatively weak deep convection, are compared to PALACE float observations from the mid-1990s, a period of stronger deep convection.

  19. Effective Removal of Nitrogen and Phosphorus from Surface Water Using Constructed Comprehensive Floating Remediation Islands

    NASA Astrophysics Data System (ADS)

    Wang, M.; Bai, S.

    2008-12-01

    Nitrogen and phosphorus are the chief pollutants of our aquatic systems which may be resulted from different contamination sources and could cause serious environmental and ecological problems. For example, nitrate contamination of the water systems from agricultural practices may be contributing to the eutrophication of the Chesapeake Bay, Maryland, USA, degrading water quality and aquatic habitats. Effective approaches for removal of nitrogen and phosphorus from our aquatic systems, particularly from surface water, is called for imminently. An in-situ remediation measure by constructed floating remediation islands has been developed and tested through the field experiments recently. Four pilot-scale settings with the different components and structures were constructed and operated in parallel in which a new type of the constructed floating remediation islands with multi-layers of substrate fillers, called the constructed multi-layer comprehensive floating remediation island, was included. The contaminated water taken directly from a river containing richly nitrogen and phosphorus was used for those experiments. The experiment results obtained from the four different experiment settings were examined. It was noticed that the degradation rates of both nitrogen and phosphorus in water in the setting with the constructed multi-layer comprehensive floating remediation island was greater than those in others. The mean removal rate of phosphorous in the experiment setting with the constructed multi-layer comprehensive floating remediation island was considerably higher than the removal rates of phosphorous in the other three experiment settings.

  20. Floating seaweed in the neustonic environment: A case study from Belgian coastal waters

    NASA Astrophysics Data System (ADS)

    Vandendriessche, Sofie; Vincx, Magda; Degraer, Steven

    2006-02-01

    Floating seaweeds form the most important natural component of all floating material found on the surface of oceans and seas. Notwithstanding the absence of natural rocky shores, ephemeral floating seaweed clumps are frequently encountered along the Belgian coast. From October 2002 to April 2003, seaweed samples and control samples (i.e. surface water samples from a seaweed-free area) were collected every other week. Multivariate analysis on neustonic macrofaunal abundances showed significant differences between seaweed and control samples in the fraction > 1 mm. Differences were less conspicuous in the 0.5-1 mm fraction. Seaweed samples were characterised by the presence of seaweed fauna e.g. Acari, Idotea baltica, Gammarus sp ., while control samples mainly contained Calanoida, Larvacea, Chaetognatha, and planktonic larvae of crustaceans and polychaetes. Seaweed samples (1 mm fraction) harboured considerably higher diversities (× 3), densities (× 18) and biomasses (× 49) compared to the surrounding water column (control samples). The impact of floating seaweeds on the neustonic environment was quantified by the calculation of the added values of seaweed samples considering biomass and density. These calculations resulted in mean added values of 311 ind m - 2 in density and 305 mg ADW m - 2 in biomass. The association degree per species was expressed as the mean percentage of individuals found in seaweed samples in proportion to the total density and biomass of that species (seaweed samples + control samples). Thirteen species showed an association percentage > 95%, and can therefore be considered members of the floating seaweed fauna.

  1. Hadfield watches a water bubble float freely in the Node 1

    NASA Image and Video Library

    2013-01-21

    ISS034-E-031694 (21 Jan. 2013) --- Canadian Space Agency astronaut Chris Hadfield, Expedition 34 flight engineer, watches a water bubble float freely between him and the camera, showing his image refracted, in the Unity node of the International Space Station.

  2. Hadfield watches a water bubble float freely in the Node 1

    NASA Image and Video Library

    2013-01-21

    ISS034-E-031695 (21 Jan. 2013) --- Canadian Space Agency astronaut Chris Hadfield, Expedition 34 flight engineer, watches a water bubble float freely between him and the camera, showing his image refracted, in the Unity node of the International Space Station.

  3. A Source for the Excellent Floating Ability of a Water Strider

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Liu, Zhan-Wei; Shi, Wen-Xiong

    2014-10-01

    A water strider's floating mechanism is of significance for the design of new biomimetic robots. However, the explanation of this mechanism has not been fully comprehended due to a lack of effective experimental methods. We describe a novel transmission speckle correlation technique, which is used to determine the deformation of liquid surfaces caused by a resting water strider, as well as a calculation of the resulting forces in the vertical direction. Furthermore, the variation of the liquid surface morphology at different times in the process of a water strider being unconscious has been measured and analyzed. The results show that the wax material secreted by water striders is a vital source for the excellent floating ability of a water strider, and that the effective time of the wax is less than 2h.

  4. Sacramento River Water Treatment Plant Intake Pier & Access Bridge, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA

  5. Mesoscale variability of water masses in the Arabian Sea as revealed by ARGO floats

    NASA Astrophysics Data System (ADS)

    Carton, X.; L'Hegaret, P.; Baraille, R.

    2012-03-01

    By analysing ARGO float data over the last four years, a few aspects of the mesoscale variability of water masses in the Arabian Sea are described. The Red Sea Outflow Water (RSOW) is concentrated in the Southwestern Gulf of Aden, in particular when a cyclonic gyre predominates in this region. Salinities of 36.5 and temperatures of 16 °C are found in this area at depths between 600 and 1000 m. RSOW is more dilute in the eastern part of the Gulf, where intense and relatively barotropic gyres mix it with Indian ocean Central Water. RSOW is also detected along the northeastern coast of Socotra, and fragments of RSOW are found between one and three degrees of latitude north of this island. In the whole Gulf of Aden, the correlation between the deep motions of the floats and the sea-level anomaly measured by altimetry is strong, at regional scale. The finer scale details of the float trajectories are not sampled by altimetry and are often related to the anomalous water masses that the floats encounter. The Persian Gulf Water (PGW) is found in the float profiles near Ras ash Sharbatat (near 57° E, 18° N), again with 36.5 in salinity and about 18-19 °C in temperature. These observations were achieved in winter when the southwestward monsoon currents can advect PGW along the South Arabian coast. Fragments of PGW were also observed in the Arabian Sea between 18 and 20° N and 63 and 65° E in summer, showing that this water mass can escape the Gulf of Oman southeastward, during that season. Kinetic energy distributions of floats with respect to distance or angle share common features between the two regions (Gulf of Aden and Arabian Sea), in particular peaks at 30, 50 and 150 km scales and along the axis of monsoon currents. Hydrological measurements by floats are also influenced by the seasonal variations of PGW and RSOW in these regions.

  6. Nitrate removal from polluted water by using a vegetated floating system.

    PubMed

    Bartucca, Maria Luce; Mimmo, Tanja; Cesco, Stefano; Del Buono, Daniele

    2016-01-15

    Nitrate (NO3(-)) water pollution is one of the most prevailing and relevant ecological issues. For instance, the wide presence of this pollutant in the environment is dramatically altering the quality of superficial and underground waters. Therefore, we set up a floating bed vegetated with a terrestrial herbaceous species (Italian ryegrass) with the aim to remediate hydroponic solutions polluted with NO3(-). The floating bed allowed the plants to grow and achieve an adequate development. Ryegrass was not affected by the treatments. On the contrary, plant biomass production and total nitrogen content (N-K) increased proportionally to the amount of NO3(-) applied. Regarding to the water cleaning experiments, the vegetated floating beds permitted to remove almost completely all the NO3(-) added from the hydroponic solutions with an initial concentration of 50, 100 and 150 mg L(-1). Furthermore, the calculation of the bioconcentration factor (BCF) indicated this species as successfully applicable for the remediation of solutions polluted by NO3(-). In conclusion, the results highlight that the combination of ryegrass and the floating bed system resulted to be effective in the remediation of aqueous solutions polluted by NO3(-). Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Mesoscale variability of water masses in the Arabian Sea as revealed by ARGO floats

    NASA Astrophysics Data System (ADS)

    Carton, X.; L'Hegaret, P.

    2011-06-01

    By analysing ARGO float data over the last four years, some aspects of the mesoscale variability of water masses in the Arabian Sea are described. The Red Sea Water outflow is strong in the Southwestern Gulf of Aden, in particular when a cyclonic gyre predominates in this region. Salinities of 36.5 and temperatures of 16 °C are found there between 600 and 1000 m depths. The Red Sea Water is more dilute in the eastern part of the Gulf, and fragments of this water mass can be advected offshore across the gulf or towards its northern coast by the regional gyres. The Red Sea Water outflow is also detected along the northeastern coast of Socotra, and fragments of RSW are found between one and three degrees of latitude north of this island. In the whole Gulf of Aden, the correlation between the deep motions of the floats and the SSH measured by altimetry is strong, at regional scale. The finer scale details of the float trajectories are more often related to the anomalous water masses that they encounter. The Persian Gulf Water (PGW) is found in the float profiles near Ras ash Sharbatat (near 57° E, 18° N), again with 36.5 in salinity and about 18-19 °C in temperature. These observations were achieved in winter when the southwestward monsoon currents can advect PGW along the South Arabian coast. Fragments of PGW are found in the Arabian Sea between 18 and 20° N and 63 and 65° E, showing that this water mass can escape the Gulf of Oman southeastward, in particular during summer.

  8. Water absorption dependent photoconductivity of a freestanding polymer bridge.

    PubMed

    Kim, Daeyoung; Choi, Jaewu

    2010-06-23

    The photo-response of a freestanding constricted polymeric solid-state bridge of water soluble sodium poly[2-(3-thienyl)-ethoxy-4-butylsulfonate] (SPTEBS) was studied as a function of water vapor pressure. The dark current dramatically increases with water vapor pressure higher than 12 Torr. Surprisingly, under light illumination, the short-circuit current of the polymeric solid-state bridge decreases with increasing water vapor pressure so that, above 12 Torr of water vapor pressure, the short-circuit current under the light illumination is even lower than the dark current. This negative photo-response of the polymeric solid-state bridge is attributed to the self-doping by hydration of the polymer and the de-doping, possibly the result of photo-induced desorption of adsorbed water molecules.

  9. Floating Vegetated Mats For Improving Surface Water Quality

    USDA-ARS?s Scientific Manuscript database

    Contamination of surface and ground waters is an environmental concern. Pollution from both point and nonpoint sources can render water unsuitable for use. Surface waters of concern include streams, rivers, ponds, lakes, canals, and wastewater lagoons. Lagooned wastewater from confined animal feedi...

  10. Bioinspired oil strider floating at the oil/water interface supported by huge superoleophobic force.

    PubMed

    Liu, Xueli; Gao, Jun; Xue, Zhongxin; Chen, Li; Lin, Ling; Jiang, Lei; Wang, Shutao

    2012-06-26

    Oil pollution to aquatic devices, especially to those oil-cleaning devices and equipment-repairing robots during oil spill accidents, has drawn great attention and remains an urgent problem to be resolved. Developing devices that can move freely in an oil/water system without contamination from oil has both scientific and practical importance. In nature, the insect water strider can float on water by utilizing the superhydrophobic supporting force received by its legs. Inspired by this unique floating phenomenon, in this article, we designed a model device named "oil strider" that could float stably at the oil/water interface without contamination by oil. The floating capability of the oil strider originated from the huge underwater superoleophobic supporting force its "legs" received. We prepared the micro/nanohierarchical structured copper-oxide-coated copper wires, acting as the artificial legs of oil strider, by a simple base-corrosion process. The surface structures and hydrophilic chemical components of the coatings on copper wires induced the huge superoleophobic force at the oil/water interface, to support the oil strider from sinking into the oil. Experimental results and theoretical analysis demonstrate that this supporting force is mainly composed of three parts: the buoyancy force, the curvature force, and the deformation force. We anticipate that this artificial oil strider will provide a guide for the design of smart aquatic devices that can move freely in an oil/water system with excellent oil repellent capability, and be helpful in practical situations such as oil handling and oil spill cleanup.

  11. Measurements of salinity, temperature, and tides in south San Francisco Bay, California, at Dumbarton Bridge; 1990-93 water years

    USGS Publications Warehouse

    Schemel, Laurence E.

    1995-01-01

    The U.S. Geological Survey measures salinity, temperature, and water levels (tides) in southern San Francisco Bay at Dumbarton Bridge as part of a cooperative program with the California State Department of Water Resources. During water years 1990-93, measurements were made at 15-minute intervals with electonic sensors located approximately one meter above the substrate in approximately six meters of water (at mean water level). During March and April of 1991 and 1992, salinity and temperature also were measured with a self-contained system floating one meter below the surface of the water. Sections of the data set were selected to illustrate influences of tidal currents, weather events, and seasonal and interannual variations in climate on salinity, temperature, and water levels at this location. The edited data are provided on high-density disks in comma-delimited, ASCII text files.

  12. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... controls, and (2) The flotation system armed when the helicopter is over water and is flying at a speed that does not exceed the maximum speed prescribed in the Rotorcraft Flight Manual for flying with...

  13. WindWaveFloat

    SciTech Connect

    Weinstein, Alla

    2011-11-01

    Presentation from the 2011 Water Peer Review includes in which principal investigator Alla Weinstein discusses project progress in development of a floating offshore wind structure - the WindFloat - and incorporation therin of a Spherical Wave Energy Device.

  14. Finescale Water-Mass Variability from ARGO Profiling Floats

    DTIC Science & Technology

    2014-09-30

    characterize lateral stirring on O(100 km) lengthscales. This variability represents the low-wavenumber source for the submesoscale being studied under...produce a spectrum for water-mass variability on isopycnals over horizontal wavelengths of 0.03-30 km (Kunze et al. 2014). The submesoscale band...other. 4 REFERENCES D’Asaro, E.A., 1988: Geneation of submesoscale vortices – A new mechanism. J. Geophys. Res., 93, 6685-6693. Ferrari, R

  15. Evaporation suppression from water reservoirs using floating covers: Lab scale observations and model predictions

    NASA Astrophysics Data System (ADS)

    Or, D.; Lehmann, P.; Aminzadeh, M.; Sommer, M.; Wey, H.; Wunderli, H.; Breitenstein, D.

    2016-12-01

    The competition over dwindling fresh water resources is expected to intensify with projected increase in human population in arid regions, expansion of irrigated land and changes in climate and drought patterns. The volume of water stored in reservoirs would also increase to mitigate seasonal shortages due to rainfall variability and to meet irrigation water needs. By some estimates up to half of the stored water is lost to evaporation thereby exacerbating the water scarcity problem. Recently, there is an upsurge in the use of self-assembling floating covers to suppress evaporation, yet the design, and implementation remain largely empirical. Studies have shown that evaporation suppression is highly nonlinear, as also known from a century of research on gas exchange from plant leaves (that often evaporate as free water surfaces through stomata that are only 1% of leaf area). We report a systematic evaluation of different cover types and external drivers (radiation, wind, wind+radiation) on evaporation suppression and energy balance of a 1.4 m2 basin placed in a wind-tunnel. Surprisingly, evaporation suppression by black and white floating covers (balls and plates) were similar despite significantly different energy balance regimes over the cover surfaces. Moreover, the evaporation suppression efficiency was a simple function of the uncovered area (square root of the uncovered fraction) with linear relations with the covered area in some cases. The thermally decoupled floating covers offer an efficient solution to the evaporation suppression with limited influence of the surface energy balance (water temperature for black and white covers was similar and remained nearly constant). The results will be linked with a predictive evaporation-energy balance model and issues of spatial scales and long exposure times will be studied.

  16. Overflow Water Pathways in the Subpolar North Atlantic Observed with Deep Floats

    NASA Astrophysics Data System (ADS)

    Bower, Amy; Furey, Heather; Lozier, Susan

    2017-04-01

    As part of the Overturning in the Subpolar North Atlantic Program (OSNAP), a total of 135 acoustically tracked RAFOS floats have been deployed in the deep boundary currents of the Iceland, Irminger and Labrador Basins, and in the Charlie-Gibbs Fracture Zone, to investigate the pathways of Iceland-Scotland Overflow Water (ISOW) and Denmark Strait Overflow Water (DSOW). Floats were released annually in 2014, 2015 and 2016 at depths between 1800 and 2800 m for two-year missions. The array of sound sources used for tracking was expanded from 10 to 13 moorings in 2016 when it was discovered that wintertime surface roughness was negatively impacting acoustic ranges. The floats from the first setting reveal several examples of persistent , deep coherent eddy motion, including a cyclonic eddy spinning off the tip of Eirik Ridge (southwest of Cape Farewell), a cyclonic eddy in the northeastern Labrador Basin near where anticyclonic Irminger Rings are formed, and an anticyclonic eddy under the North Atlantic Current (NAC) in the central Iceland Basin. A consistent region of boundary-interior exchange was observed near Hamilton Bank on the western boundary of the Labrador Sea. Deep cyclonic recirculation gyres are revealed in all three basins. Floats released in the southward-flowing deep boundary current over the eastern flank of the Reykjanes Ridge show that shallower layers of ISOW peel off to the west and cross the Ridge into the Irminger Basin through various gaps south of 60°N, including the Bight Fracture Zone. These floats tend to turn northward and continue along the slope in the Irminger Basin. Interestingly, floats released at the ISOW level in the CGFZ did not turn into the Irminger Basin as often depicted in deep circulation schematics, but rather drifted west-northwestward toward the Labrador Sea, or eddied around west of the CGFZ and (in some cases) turned southward. This result is consistent with some previous hydrographic and high-resolution model results

  17. Evaporation and energy balance of partially covered water reservoirs using self-assembling floating elements

    NASA Astrophysics Data System (ADS)

    Aminzadeh, Milad; Lehmann, Peter; Or, Dani

    2017-04-01

    The projected increase in fresh water storage to meet growing municipal and irrigation needs and mitigate effects of rainfall variability and prolonged droughts will require new measures for suppressing evaporation from reservoirs and conserve water resources. A low risk and cost effective means for evaporation suppression uses self-assembling floating elements. We seek to develop a systematic framework for quantifying impacts of various cover designs and properties on heat and mass fluxes and energy balance of water reservoirs of different characteristics and climatic regions. The vertical energy balance equation including diurnal and seasonal variations in atmospheric forcing and energy transport to the water column was employed to resolve temperature and flux dynamics from water bodies. We then consider energy coupling of a unit floating cover element with water body (including lateral heat exchanges) to evaluate effect of different cover designs, climate conditions, and reservoir characteristics on evaporation suppression and energy balance of water body. The mechanistic framework offers a means for evaluating ecological impacts of covers, enables consideration of different cover designs (shape, size, thermal and radiative properties), and advances this largely empirical resource conservation strategy into a predictive framework for design and management purposes.

  18. Ignition of a floating droplet of organic coal-water fuel

    NASA Astrophysics Data System (ADS)

    Nakoryakov, V. E.; Kuznetsov, G. V.; Strizhak, P. A.

    2016-06-01

    The results of experimental investigations are presented for the ignition of droplets (particles) of organic coal-water fuels (OCWFs) floating in a flow of an oxidizer using a special combustion chamber from high-temperature quartz glass. The temperature and the velocity of motion of the oxidizer vary in the ranges of 500-900 K and 0.5-3 m/s. The initial sizes (radii) of fuel droplets amounted to 0.3-1.5 mm. As the basic OCWF components, particles (of 80-100 µm in size) of brown coal "B2," water, mazut, and waste castor and compressor oils are used. With use of the system of high-velocity video registration, the conditions providing for floating of OCWF particles without initiation of burning and with the subsequent steady ignition are established. Four modes of OCWF-droplet ignition with different trajectories of their motion in the combustion chamber are singled out. The times of the OCWF-ignition delay in dependence on the size of fuel particles and oxidizer temperatures are determined. The deviations of the OCWF-ignition-delay times obtained under conditions of suspension of a droplet on the thermocouple junction and while floating in the oxidizer flow are established.

  19. Video-Bubbles Inserted Into a Floating Drop of Water on the International Space Station (ISS)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Saturday Morning Science, the science of opportunity series of applied experiments and demonstrations, performed aboard the International Space Station (ISS) by Expedition 6 astronaut Dr. Don Pettit, revealed some remarkable findings. Inserting a bubble into a floating ball of water in space is difficult, as Pettit demonstrates in this video. Blowing the bubble is the easy part. Getting it to stay in the center of the ball of water is much more difficult. Watch the video to see the technique Dr. Pettit finally uses and see the resulting visual surprise offered by the ensuing optical properties.

  20. Video-Bubbles Inserted Into a Floating Drop of Water on the International Space Station (ISS)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Saturday Morning Science, the science of opportunity series of applied experiments and demonstrations, performed aboard the International Space Station (ISS) by Expedition 6 astronaut Dr. Don Pettit, revealed some remarkable findings. Inserting a bubble into a floating ball of water in space is difficult, as Pettit demonstrates in this video. Blowing the bubble is the easy part. Getting it to stay in the center of the ball of water is much more difficult. Watch the video to see the technique Dr. Pettit finally uses and see the resulting visual surprise offered by the ensuing optical properties.

  1. Identification of wave energy potential with floating oscillating water column technology in Pulau Baai Beach, Bengkulu

    NASA Astrophysics Data System (ADS)

    Alifdini, I.; Sugianto, D. N.; Andrawina, Y. O.; Widodo, A. B.

    2017-02-01

    Pulau Baai is a beach which is located in Bengkulu, Indonesia. This location has swell waves which is beneficial for wave energy, because it directly faces the Indian Ocean. Floating Oscillating Water Column (OWC) is a prototype used to generate electricity from wave energy. The objective of this research is to identify how much electricity can be generated from floating OWC. This research used a quantitative method by processing wind data (speed and direction) from ogimet.com in 2000-2016. The wind speed rate for wave energy potential of this location is above 5.14 m/s. Wind data is converted to significant wave height and periods data by Sverdrup, Munk, and Bretschneider (SMB) method. Significant wave height rate of this location is 0.06 – 5.33 meters. Assuming that this power plant uses 3 chambers of floating OWC, the power output of OWC is 1.9 GW/year. Thus, suppose each residents’ house uses 1300 watt, this power plant can be used for 1,461,538 residents per year.

  2. Floating bioplato for purification of waste quarry waters from mineral nitrogen compounds in the Arctic.

    PubMed

    Evdokimova, Galina A; Ivanova, Lyubov A; Mozgova, Natalia P; Myazin, Vladimir A; Fokina, Nadezhda V

    2016-08-23

    A bioplato was organized at Kirovogorskiy pond-settling of OLKON Company (the city of Olenegorsk, in Murmansk region) to reduce the content of nitrogen mineral compounds in water which come into the pond with the quarry waters after blasting operations using nitrogen compounds. The assortment of aboriginal plants was selected, a method of fixing and growing them on the water surface was developed, and observations of their vegetation were carried out. The dynamics of nitrogen compounds was determined in the laboratory and with full-scale tests. The coverage area pond by plants for the effective reduction of mineral nitrogen compounds was calculated. The use of floating bioplato helped to reduce content of ammonium and nitrite to maximum permissible levels or even lower in pond water. Also there was a tendency towards reduction of nitrate concentrations in water. The developmental technology can be used in any climatic zone with a specific assortment of plants-ameliorants.

  3. Shockwave generation by a semiconductor bridge operation in water

    SciTech Connect

    Zvulun, E.; Toker, G.; Gurovich, V. Tz.; Krasik, Ya. E.

    2014-05-28

    A semiconductor bridge (SCB) is a silicon device, used in explosive systems as the electrical initiator element. In recent years, SCB plasma has been extensively studied, both electrically and using fast photography and spectroscopic imaging. However, the value of the pressure buildup at the bridge remains unknown. In this study, we operated SCB devices in water and, using shadow imaging and reference beam interferometry, obtained the velocity of the shock wave propagation and distribution of the density of water. These results, together with a self-similar hydrodynamic model, were used to calculate the pressure generated by the exploding SCB. In addition, the results obtained showed that the energy of the water flow exceeds significantly the energy deposited into the exploded SCB. The latter can be explained by the combustion of the aluminum and silicon atoms released in water, which acts as an oxidizing medium.

  4. Float launch system

    SciTech Connect

    Ayers, R.R.

    1989-09-26

    This patent describes a method for deploying a seismic subarray, which includes a float, seismic gun support beam and umbilical cable, from a vessel. It comprises: putting the vessel underway; connecting the subarray to the vessel by a detachable saddle rigged via a cable from a boom; moving the subarray along the length of the boom outboard of the vessel; deploying the seismic gun support beam from the float into the water, whereby the beam stabilizes the subarray; lowering the float to the water; releasing the detachable saddle from the float; towing the released float with the vessel by the umbilical cable; and raising the detached saddle.

  5. Ignition of an organic water-coal fuel droplet floating in a heated-air flow

    NASA Astrophysics Data System (ADS)

    Valiullin, T. R.; Strizhak, P. A.; Shevyrev, S. A.; Bogomolov, A. R.

    2017-01-01

    Ignition of an organic water-coal fuel (CWSP) droplet floating in a heated-air flow has been studied experimentally. Rank B2 brown-coal particles with a size of 100 μm, used crankcase Total oil, water, and a plasticizer were used as the main CWSP components. A dedicated quartz-glass chamber has been designed with inlet and outlet elements made as truncated cones connected via a cylindrical ring. The cones were used to shape an oxidizer flow with a temperature of 500-830 K and a flow velocity of 0.5-5.0 m/s. A technique that uses a coordinate-positioning gear, a nichrome thread, and a cutter element has been developed for discharging CWSP droplets into the working zone of the chamber. Droplets with an initial size of 0.4 to 2.0 mm were used. Conditions have been determined for a droplet to float in the oxidizer flow long enough for the sustainable droplet burning to be initiated. Typical stages and integral ignition characteristics have been established. The integral parameters (ignition-delay times) of the examined processes have been compared to the results of experiments with CWSP droplets suspended on the junction of a quick-response thermocouple. It has been shown that floating fuel droplets ignite much quicker than the ones that sit still on the thermocouple due to rotation of an CWSP droplet in the oxidizer flow, more uniform heating of the droplet, and lack of heat drainage towards the droplet center. High-speed video recording of the peculiarities of floatation of a burning fuel droplet makes it possible to complement the existing models of water-coal fuel burning. The results can be used for a more substantiated modeling of furnace CWSP burning with the ANSYS, Fluent, and Sigma-Flow software packages.

  6. Buoyancy of a thin plate pressing a floating oil film on water.

    PubMed

    Ji, Xiang-Ying; Feng, Xi-Qiao

    2013-06-04

    Because of the superhydrophobicity of their legs, water striders and many other aquatic creatures can stand and walk effortlessly on water. Because of pollution, an oil film may exist on water in some practical situations. To date, however, it remains unclear how the presence of an oil film would affect the wetting behavior of an object floating on water. In this work, we investigated, both theoretically and experimentally, the buoyancy of a thin plate pressing the surface of a bilayered liquid system. In particular, the effect of the oil layer on the buoyancy force was examined. The critical depth and the corresponding buoyancy at the penetration of the plate into the liquids were obtained analytically. For a plate vertically pressing the liquid surface, the force-displacement loop during a complete advancing-receding cycle was analyzed. Experiments were also performed to verify the theoretical results.

  7. Enhanced load-carrying capacity of hairy surfaces floating on water.

    PubMed

    Xue, Yahui; Yuan, Huijing; Su, Weidong; Shi, Yipeng; Duan, Huiling

    2014-05-08

    Water repellency of hairy surfaces depends on the geometric arrangement of these hairs and enables different applications in both nature and engineering. We investigate the mechanism and optimization of a hairy surface floating on water to obtain its maximum load-carrying capacity by the free energy and force analyses. It is demonstrated that there is an optimum cylinder spacing, as a result of the compromise between the vertical capillary force and the gravity, so that the hairy surface has both high load-carrying capacity and mechanical stability. Our analysis makes it clear that the setae on water striders' legs or some insects' wings are in such an optimized geometry. Moreover, it is shown that surface hydrophobicity can further increase the capacity of a hairy surface with thick cylinders, while the influence is negligible when the cylinders are thin.

  8. The reaction on a float bottom when making contact with water at high speeds

    NASA Technical Reports Server (NTRS)

    Richardson, H C

    1928-01-01

    Tests were conducted to investigate the possibility of a serious accident arising from unintentional contact with the water in substantially horizontal flight at high speed. Referring to vector diagrams on Figure 2, it will be seen that a very dangerous condition may arise if the float be allowed to come in contact with the water at high speeds as, for example, when flying at high speed just above the water. The initial diving moment due to suction and drag combined may be great enough to cause the seaplane to nose under before the pilot is able to control the motion. The same test data indicate clearly the existence of forces and moments tending to produce the phenomenon observed by Mr. Carroll (Technical Note No. 287) when the maneuver is carried out at lower speeds, as in a landing.

  9. Enhanced load-carrying capacity of hairy surfaces floating on water

    PubMed Central

    Xue, Yahui; Yuan, Huijing; Su, Weidong; Shi, Yipeng; Duan, Huiling

    2014-01-01

    Water repellency of hairy surfaces depends on the geometric arrangement of these hairs and enables different applications in both nature and engineering. We investigate the mechanism and optimization of a hairy surface floating on water to obtain its maximum load-carrying capacity by the free energy and force analyses. It is demonstrated that there is an optimum cylinder spacing, as a result of the compromise between the vertical capillary force and the gravity, so that the hairy surface has both high load-carrying capacity and mechanical stability. Our analysis makes it clear that the setae on water striders' legs or some insects' wings are in such an optimized geometry. Moreover, it is shown that surface hydrophobicity can further increase the capacity of a hairy surface with thick cylinders, while the influence is negligible when the cylinders are thin. PMID:24808757

  10. Effects on the Underlying Water Column by Extensive Floating Treatment Wetlands.

    PubMed

    Strosnider, W H; Schultz, S E; Strosnider, K A Johnson; Nairn, R W

    2017-01-01

    Floating treatment wetlands (FTWs) are an emerging engineering option with promise for simultaneous water quality improvement and habitat creation. Relatively little research has been published regarding their construction or effects on the underlying water column. In this field-scale experiment, four different extensive FTW designs were constructed using minimal materials, including drainpipe, burlap, mulch, utility netting, and reused polyethylene bottles. The FTWs were then planted with spp. (cattail) and L. (common rush). Over 28 mo, the water column beneath FTWs in two test ponds was compared to that in an open water control pond. The ponds (190 ± 10 m) were fed with well water enriched with nitrate to emulate agricultural ponds. Although observed differences were relatively small, statistically significant differences were noted. With respect to the control, waters underneath FTWs had lower dissolved oxygen, sulfate, nitrate, and pH, dampened diurnal temperature fluctuations, and greater alkalinity. The FTWs created habitat and were colonized by species of insects, birds, amphibians, snails, and spiders. Results indicated that spp. is suitable for FTW creation. However, a more supportive planting matrix is suggested to encourage faster plant growth and protect against wind and wave action damage. Although plant growth was limited, results suggest that FTWs may be applied to encourage less aerobic and more organic rich and thermally insulated conditions for water quality improvement in agricultural ponds and other aquatic systems while also creating valuable habitat. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. Morphology-induced collective behaviors: dynamic pattern formation in water-floating elements.

    PubMed

    Nakajima, Kohei; Ngouabeu, Aubery Marchel Tientcheu; Miyashita, Shuhei; Göldi, Maurice; Füchslin, Rudolf Marcel; Pfeifer, Rolf

    2012-01-01

    Complex systems involving many interacting elements often organize into patterns. Two types of pattern formation can be distinguished, static and dynamic. Static pattern formation means that the resulting structure constitutes a thermodynamic equilibrium whose pattern formation can be understood in terms of the minimization of free energy, while dynamic pattern formation indicates that the system is permanently dissipating energy and not in equilibrium. In this paper, we report experimental results showing that the morphology of elements plays a significant role in dynamic pattern formation. We prepared three different shapes of elements (circles, squares, and triangles) floating in a water-filled container, in which each of the shapes has two types: active elements that were capable of self-agitation with vibration motors, and passive elements that were mere floating tiles. The system was purely decentralized: that is, elements interacted locally, and subsequently elicited global patterns in a process called self-organized segregation. We showed that, according to the morphology of the selected elements, a different type of segregation occurs. Also, we quantitatively characterized both the local interaction regime and the resulting global behavior for each type of segregation by means of information theoretic quantities, and showed the difference for each case in detail, while offering speculation on the mechanism causing this phenomenon.

  12. Morphology-Induced Collective Behaviors: Dynamic Pattern Formation in Water-Floating Elements

    PubMed Central

    Nakajima, Kohei; Ngouabeu, Aubery Marchel Tientcheu; Miyashita, Shuhei; Göldi, Maurice; Füchslin, Rudolf Marcel; Pfeifer, Rolf

    2012-01-01

    Complex systems involving many interacting elements often organize into patterns. Two types of pattern formation can be distinguished, static and dynamic. Static pattern formation means that the resulting structure constitutes a thermodynamic equilibrium whose pattern formation can be understood in terms of the minimization of free energy, while dynamic pattern formation indicates that the system is permanently dissipating energy and not in equilibrium. In this paper, we report experimental results showing that the morphology of elements plays a significant role in dynamic pattern formation. We prepared three different shapes of elements (circles, squares, and triangles) floating in a water-filled container, in which each of the shapes has two types: active elements that were capable of self-agitation with vibration motors, and passive elements that were mere floating tiles. The system was purely decentralized: that is, elements interacted locally, and subsequently elicited global patterns in a process called self-organized segregation. We showed that, according to the morphology of the selected elements, a different type of segregation occurs. Also, we quantitatively characterized both the local interaction regime and the resulting global behavior for each type of segregation by means of information theoretic quantities, and showed the difference for each case in detail, while offering speculation on the mechanism causing this phenomenon. PMID:22715370

  13. Microbial mechanisms of using enhanced ecological floating beds for eutrophic water improvement.

    PubMed

    Wu, Qing; Hu, Yue; Li, Shuqun; Peng, Sen; Zhao, Huabing

    2016-07-01

    Enhanced ecological floating beds were implemented to reduce nutrient quantity and improve the water quality of a eutrophic lake. The results showed that average removal efficiencies of CODCr, total nitrogen, NH3-N and total phosphorus for Canna indica L. set-up were 23.1%, 15.3%, 18.1% and 19.4% higher, respectively, than that of the setup with only substrate, and 14.2%, 12.8%, 7.9% and 11.9% higher than Iris pseudacorus L. ecological floating bed. The microbial community structure had obvious differences between devices and low similarity; bacteria were mainly attached on the fiber filling. The microbial population was abundant at the start and end of the experiment. Shannon index of samples selected ranged from 0.85 to 1.05. The sequencing results showed that fiber filling collected most uncultured bacteria species and the majority of bacteria on the plant roots were β-Proteobacteria and α-Proteobacteria. The co-dominant species attaching to the filling and plant was Nitrosomonadaceae. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Fate of NO and NH in the treatment of eutrophic water using the floating macrophyte.

    PubMed

    Gao, Yan; Yi, Neng; Zhang, Zhiyong; Liu, Haiqin; Yan, Shaohua

    2012-01-01

    Use of the floating aquatic macrophyte, , to improve eutrophic water quality is practiced on a large scale in China. Limited information is available on the relative importance of the biological NO or NH removal process during the treatment of eutrophic water using . To investigate the key process responsible for the removal of NO and NH, N-NO (9.98 atom % [at.%] N) or N-NH (10.08 at.% N) was added to obtain eutrophic water with or without the cultivation of . In the unplanted water, considerable proportions of the added N-NO (27.13 ± 4.87%) or N-NH (42.08 ± 7.22%) were assimilated by the developed algae. The growth of controlled algae development in the planted water. Furthermore, the cultivation of stimulated gaseous loss of N by microbial denitrification (8.61 ± 1.70% NO-N loss from N-NO-labeled water). Apart from N loss by denitrification, considerable proportions of the added N-NO (62.01 ± 6.93%) or N-NH (76.76 ± 6.21%) were assimilated into the macrophyte N pools. The fine root detritus of contained a proportion of N (4.37 ± 1.39% in NO-labeled water, 2.03 ± 0.52% in NH-labeled water) that will be returned to the water after decomposition. In addition to N loss via NO emission, an unaccounted proportion of N could be mainly due to gaseous loss as N by denitrification (25.00% in N-NO-labeled water with Eichhornia crassipes) Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  15. Synthesis of highly hydrophobic floating magnetic polymer nanocomposites for the removal of oils from water surface

    NASA Astrophysics Data System (ADS)

    Chen, Mudan; Jiang, Wei; Wang, Fenghe; Shen, Ping; Ma, Peichang; Gu, Junjun; Mao, Jianyu; Li, Fengsheng

    2013-12-01

    The removal of organic contaminants, particularly oil spills from water surface is of great technological importance for environmental protection. In this article, we present a novel, economic and environment-friendly core-shell composite material based on magnetic hollow Fe3O4 nanoparticles (MNPs) that was fabricated by two-step process, which can fast and efficiently separate oils from water surface under a magnetic field. The magnetic Fe3O4 nanoparticles (MNPs) were coated with a polystyrene layer successfully to form water-repellent and oil-absorbing surfaces, which could float on water and selectively absorb lubricating oil up to 3 times of the particles’ weight while completely repelling water. More importantly, the oils could be readily removed from the surfaces of nanocomposites by a simple treatment and the nanocomposites still kept highly hydrophobic and superoleophilic characteristics, so the nanocomposites have an excellent recyclability in the oil-absorbent capacity. Several techniques such as transmission electron microscope (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were used in the characterization of the materials. In addition, magnetic force and oils removal capability tests were also performed. It will open up a potential and broad application in wastewater treatment.

  16. Floating sample-collection platform with stage-activated automatic water sampler for streams with large variation in stage

    USGS Publications Warehouse

    Tarte, Stephen R.; Schmidt, A.R.; Sullivan, Daniel J.

    1992-01-01

    A floating sample-collection platform is described for stream sites where the vertical or horizontal distance between the stream-sampling point and a safe location for the sampler exceed the suction head of the sampler. The platform allows continuous water sampling over the entire storm-runoff hydrogrpah. The platform was developed for a site in southern Illinois.

  17. Injuries of the floating crew of the Northern water pool in a state of alcoholic intoxication.

    PubMed

    Shapovalov, Konstantin A

    2013-01-01

    The analysis of injuries of floating crew of the Northern water pool in a state of alcoholic intoxication havebeen based on the 180 accidents on board of ships with temporary loss of ability to work, and 1686 casehistories with alcoholic injuries, which demanded treatment in a surgical department. Among persons,the received injuries on the ship in the state of alcoholic intoxication were 8.1% of the victims: in thestrength of the transport fleet - 8.9%; fishing - 8.9% and river ones - 4.1%. Masters of fish production,skippers, rulers of the radio stations and masters of fish processing were most frequently injured afterthe consumption of the alcoholic beverages. Alcoholic injuries have been recorded at the time of walkingon the catwalk and the decks (54.2%), mooring operations (15.1%), maintenance and repairing the deckmachinery, water preparation (6.6%), as well as boat and loading-unloading works (4.3%). Falls from heightconstituted 36.6% of the injuries. Alcohol in 3.2 times increases the weight of the combined injuries. Thedeaths from the alcohol related injuries in marine conditions (43.4%) significantly exceed the indicators inthe group of non-alcoholic injuries (7.0%). Alcoholic intoxication has been noted in 35.0% of the cases ofthe floating crew injuries, hospitalised in the surgical department. Victims with alcoholic injuries receivedduring performing ship's works were hospitalised 10 times less, than those with non-productive types ofinjuries. In the structure of non-industrial injuries, household injuries prevail (78.2%) over those receiveddue to falls on the street, in pedestrian flows (10.3%), transport and traffic accidents (6.7%), intentionalinjuries (4.1%) or those connected with sports games and competitions (0.7%). Fishermen are a professionalgroup of seamen, subject to the high social vulnerability to the alcoholic beverages consumptionand related injuries.

  18. The NACA Impact Basin and Water Landing Tests of a Float Model at Various Velocities and Weights

    NASA Technical Reports Server (NTRS)

    Batterson, Sidney A

    1944-01-01

    The first data obtained in the United States under the controlled testing conditions necessary for establishing relationships among the numerous parameters involved when a float having both horizontal and vertical velocity contacts a water surface are presented. The data were obtained at the NACA impact basin. The report is confined to a presentation of the relationship between resultant velocity and impact normal acceleration for various float weights when all other parameters are constant. Analysis of the experimental results indicated that the maximum impact normal acceleration was proportional to the square of the resultant velocity, that increases in float weight resulted in decreases in the maximum impact normal acceleration, and that an increase in the flight-path angle caused increased impact normal acceleration.

  19. 75 FR 49408 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Bridges

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... Waters; Technical, Organizational, and Conforming Amendments, Bridges AGENCY: Coast Guard, DHS. ACTION... this rule is to make conforming amendments and technical corrections to Coast Guard bridge and... regarding bridge matters, nor will it change the substance of the public's involvement in the process. The...

  20. How Does the Gibbs Inequality Condition Affect the Stability and Detachment of Floating Spheres from the Free Surface of Water?

    PubMed

    Feng, Dong-xia; Nguyen, Anh V

    2016-03-01

    Floating objects on the air-water interfaces are central to a number of everyday activities, from walking on water by insects to flotation separation of valuable minerals using air bubbles. The available theories show that a fine sphere can float if the force of surface tension and buoyancies can support the sphere at the interface with an apical angle subtended by the circle of contact being larger than the contact angle. Here we show that the pinning of the contact line at the sharp edge, known as the Gibbs inequality condition, also plays a significant role in controlling the stability and detachment of floating spheres. Specifically, we truncated the spheres with different angles and used a force sensor device to measure the force of pushing the truncated spheres from the interface into water. We also developed a theoretical modeling to calculate the pushing force that in combination with experimental results shows different effects of the Gibbs inequality condition on the stability and detachment of the spheres from the water surface. For small angles of truncation, the Gibbs inequality condition does not affect the sphere detachment, and hence the classical theories on the floatability of spheres are valid. For large truncated angles, the Gibbs inequality condition determines the tenacity of the particle-meniscus contact and the stability and detachment of floating spheres. In this case, the classical theories on the floatability of spheres are no longer valid. A critical truncated angle for the transition from the classical to the Gibbs inequality regimes of detachment was also established. The outcomes of this research advance our understanding of the behavior of floating objects, in particular, the flotation separation of valuable minerals, which often contain various sharp edges of their crystal faces.

  1. Enhancing the water purification efficiency of a floating treatment wetland using a biofilm carrier.

    PubMed

    Zhang, Lingling; Zhao, Jing; Cui, Naxin; Dai, Yanran; Kong, Lingwei; Wu, Juan; Cheng, Shuiping

    2016-04-01

    Floating treatment wetlands (FTWs) and biofilm carriers are widely used in water purification. The objective of the present work was to explore whether and to what extent an FTW integrated with plants and biofilm carriers (FTW-I) could enhance the nutrient removal efficiency. Significantly higher removal rates of ammonia nitrogen (85.2 %), total phosphorus (82.7 %), and orthophosphate (82.5 %) were observed in the FTW-I treatment relative to the FTW with plants (FTW-P; 80.0, 78.5, and 77.6 %, respectively) and the FTW with biofilm carriers (FTW-B; 56.7, 12.9, and 13.4 %, respectively) (p < 0.05). The mass balance results indicated that plant uptake was the main pathway for N and P removal (accounting for 58.1 and 91.4 %, respectively) in FTW-I, in which only 1.2 % of the N and 5.7 % of the P was deposited on the bottom of the tank. In addition, the plants translocated 43.9 and 80.2 % of the N and P in the water and 83.5 and 88.3 % of the absorbed N and P, respectively, into their aboveground tissues. The combination of an FTW and biofilm carriers can improve the efficiency of water purification, and nutrients can be rapidly removed from the system by harvesting the aboveground plant tissues.

  2. Floating elementary osmotic pump tablet (FEOPT) for controlled delivery of diethylcarbamazine citrate: a water-soluble drug.

    PubMed

    Khan, Zulfequar Ahamad; Tripathi, Rahul; Mishra, Brahmeshwar

    2011-12-01

    The present work investigates the feasibility of the design of a novel floating elementary osmotic pump tablet (FEOPT) to prolong the gastric residence of a highly water-soluble drug. Diethylcarbamazine citrate (DEC) was chosen as a model drug. The FEOPT consisted of an osmotic core (DEC, mannitol, and hydrophilic polymers) coated with a semipermeable layer (cellulose acetate) and a gas-generating gelling layer (sodium bicarbonate, hydrophilic polymers) followed by a polymeric film (Eudragit RL 30D). The effect of formulation variables such as concentration of polymers, types of diluent, and coat thickness of semipermeable membrane was evaluated in terms of physical parameters, floating lag time, duration of floatation, and in vitro drug release. The Fourier transform infrared and X-ray diffraction analysis were carried out to study the physicochemical changes in the drug excipients powder blend. The integrity of the orifice and polymeric film layer was confirmed from scanning electron microscopy image. All the developed FEOPT showed floating lag time of less than 8 min and floating duration of 24 h. A zero-order drug release could be attained for DEC. The formulations were found to be stable up to 3 months of stability testing at 40°C/75% relative humidity.

  3. Fasciola hepatica and Paramphistomum daubneyi: field observations on the transport and outcome of floating metacercariae in running water.

    PubMed

    Rondelaud, D; Vignoles, P; Vareille-Morel, C; Abrous, M; Mage, C; Mouzet, R; Dreyfuss, G

    2004-06-01

    Experimental investigations in eight open drainage ditches and furrows from central France were carried out to analyse the dispersal of floating metacercariae of two digenean species by running water and to determine the outcome of larvae which settled on Nasturtium officinale (watercress). The frequencies of larvae found after their transport by water ranged from 33% to 49.7%, thus indicating that more than half of the metacercariae used in this experiment had fallen to the bottom of the water during this transport. The nature of the site (furrow, or ditch supplied by a spring) had a significant effect on the distribution of floating larvae, while the digenean species had no effect. Low percentages of metacercariae on watercress were noted in furrows (3.5-4.3% of larvae) and ditches (0.8-1.3%). When the watercress grew, most larvae that had settled on leaves and stems died but there were always several living metacercariae on this plant (0.7-1.5% of larvae for Fasciola hepatica and 0.2-0.5% for Paramphistomum daubneyi). The weak buoyancy of these floating cysts on running water limited their dispersal and, consequently, led to a real diminution of risks incurred by definitive hosts towards these metacercariae.

  4. Quantum study of HIV-1 protease-bridge water interaction

    NASA Astrophysics Data System (ADS)

    Duan, Li L.; Tong, Yan; Mei, Ye; Zhang, Qing G.; Zhang, John Z. H.

    2007-10-01

    We present a fully quantum mechanical calculation for binding interaction between HIV-1 protease (PR) and the water molecule W301 which bridges the flaps of the protease with the inhibitors of PR. The quantum calculation is made possible by applying a recently developed molecular fractionation with conjugate caps (MFCC) method which divides a protein molecule into capped amino acid-based fragments and their conjugate caps. These individual fragments are properly treated to preserve the chemical property of bonds that are cut. Ab initio methods at HF, B3LYP, and MP2 levels with a fixed basis set 6-31+G* have been employed in the present calculation. The MFCC calculation produces a quantum mechanical interaction "map" representing interactions between individual residues of PR and W301. This enables a detailed quantitative analysis on binding of W301 to specific residues of PR at quantum mechanical level.

  5. Spatial distribution of floating marine debris in offshore continental Portuguese waters.

    PubMed

    Sá, Sara; Bastos-Santos, Jorge; Araújo, Hélder; Ferreira, Marisa; Duro, Virginia; Alves, Flávia; Panta-Ferreira, Bruno; Nicolau, Lídia; Eira, Catarina; Vingada, José

    2016-03-15

    This study presents data on abundance and density of macro-floating marine debris (FMD), including their composition, spatial distribution and potential sources off continental Portugal. FMD were assessed by shipboard visual surveys covering ±252,833 km(2) until the 220 nm limit. The FMD average density was 2.98 items/km(2) and abundance amounted to 752,740 items. Unidentified plastics constitute the major bulk of FMD (density=0.46 items/km(2); abundance=117,390 items), followed by styrofoam, derelict or lost materials from fisheries, paper/cardboard and wood material. The North sector of the area presents higher FMD diversity and abundances, probably as a result of the high number of navigation corridors and fisheries operating in that sector. Most FMD originate from local sources, namely discharges from vessels and derelict material from fisheries. Considering the identifiable items, cables and fishing lines were the only fishing related items among the top ten FMD items in Portuguese offshore waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Spectrum response estimation for deep-water floating platforms via retardation function representation

    NASA Astrophysics Data System (ADS)

    Liu, Fushun; Liu, Chengcheng; Chen, Jiefeng; Wang, Bin

    2017-08-01

    The key concept of spectrum response estimation with commercial software, such as the SESAM software tool, typically includes two main steps: finding a suitable loading spectrum and computing the response amplitude operators (RAOs) subjected to a frequency-specified wave component. In this paper, we propose a nontraditional spectrum response estimation method that uses a numerical representation of the retardation functions. Based on estimated added mass and damping matrices of the structure, we decompose and replace the convolution terms with a series of poles and corresponding residues in the Laplace domain. Then, we estimate the power density corresponding to each frequency component using the improved periodogram method. The advantage of this approach is that the frequency-dependent motion equations in the time domain can be transformed into the Laplace domain without requiring Laplace-domain expressions for the added mass and damping. To validate the proposed method, we use a numerical semi-submerged pontoon from the SESAM. The numerical results show that the responses of the proposed method match well with those obtained from the traditional method. Furthermore, the estimated spectrum also matches well, which indicates its potential application to deep-water floating structures.

  7. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates.

    PubMed

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-03-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges.

  8. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

    PubMed Central

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-01-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges. PMID:26928329

  9. Pathways of Labrador Sea Water Export: A Simulation of Float Behaviour in a Numerical Model.

    NASA Astrophysics Data System (ADS)

    Getzlaff, K.; Dengg, J.; Boening, C.

    2003-04-01

    A paradigm of LSW export into the Subtropical Gyre was that it takes place as a concentrated deep western boundary current around the Grand Banks of Newfoundland. However, recent studies using PALACE floats demonstrated severe problems of the floats in following this path. In this study we use a suite of high-resolution (1/12o) eddy-resolving numerical experiments to shed light on the following questions: begin{itemize} Which factors determine the existence of a continuous DWBC around the Grand Banks? Which processes are responsible for extracting floats from the DWBC and to which degree are the simulated floats able to follow this continuous path? In particular, the focus will be on the interaction of eddies with the DWBC and on the behaviour of profiling floats in a vertically sheared flow field. In the Simulation, floats optionally follow the model's velocity field, either in 3-dimensions or on geopotential surfaces. A quantification of export rates from the Labrador Sea is attempted by using volume-preserving Lagrangian particles.

  10. Developing an ecosystem model of a floating wetland for water quality improvement on a stormwater pond.

    PubMed

    McAndrew, Brendan; Ahn, Changwoo

    2017-11-01

    An ecosystem model was developed to assist with designing and implementing a floating wetland (FW) for water quality management of urban stormwater ponds, focusing on nitrogen (N) removal. The model is comprised of three linked submodels: hydrology, plant growth, and nitrogen. The model was calibrated with the data that resulted from a FW constructed and implemented as part of an interdisciplinary pedagogical project on a university campus, titled "The Rain Project", which raised awareness of stormwater issues while investigating the potential application of green infrastructure for sustainable stormwater management. The FW had been deployed during the summer of 2015 (i.e., May through mid-September) on a major stormwater pond located at the center of the Fairfax Campus of George Mason University near Washington, D.C. We used the model to explore the impact of three design elements of FW (i.e., hydraulic residence time (HRT), surface area coverage, and primary productivity) on the function of FW. Model simulations showed enhanced N removal performance as HRT and surface area coverage increased. The relatively low macrophyte productivity observed indicates that, in the case of our pond and FW, N removal was very limited. The model results suggest that even full pond surface coverage would result in meager N removal (∼6%) at a HRT of one week. A FW with higher plant productivity, more representative of that reported in the literature, would require only 10% coverage to achieve similar N removal efficiency (∼7%). Therefore, macrophyte productivity appears to have a greater impact on FW performance on N removal than surface area coverage or pond HRT. The outcome of the study shows that this model, though limited in scope, may be useful in aiding the design of FW to augment the performance of degraded stormwater ponds in an effort to meet local water quality goals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. First autonomous bio-optical profiling float in the Gulf of Mexico reveals dynamic biogeochemistry in deep waters.

    PubMed

    Green, Rebecca E; Bower, Amy S; Lugo-Fernández, Alexis

    2014-01-01

    Profiling floats equipped with bio-optical sensors well complement ship-based and satellite ocean color measurements by providing highly-resolved time-series data on the vertical structure of biogeochemical processes in oceanic waters. This is the first study to employ an autonomous profiling (APEX) float in the Gulf of Mexico for measuring spatiotemporal variability in bio-optics and hydrography. During the 17-month deployment (July 2011 to December 2012), the float mission collected profiles of temperature, salinity, chlorophyll fluorescence, particulate backscattering (bbp), and colored dissolved organic matter (CDOM) fluorescence from the ocean surface to a depth of 1,500 m. Biogeochemical variability was characterized by distinct depth trends and local "hot spots", including impacts from mesoscale processes associated with each of the water masses sampled, from ambient deep waters over the Florida Plain, into the Loop Current, up the Florida Canyon, and eventually into the Florida Straits. A deep chlorophyll maximum (DCM) occurred between 30 and 120 m, with the DCM depth significantly related to the unique density layer ρ = 1023.6 (R2 = 0.62). Particulate backscattering, bbp, demonstrated multiple peaks throughout the water column, including from phytoplankton, deep scattering layers, and resuspension. The bio-optical relationship developed between bbp and chlorophyll (R2 = 0.49) was compared to a global relationship and could significantly improve regional ocean-color algorithms. Photooxidation and autochthonous production contributed to CDOM distributions in the upper water column, whereas in deep water, CDOM behaved as a semi-conservative tracer of water masses, demonstrating a tight relationship with density (R2 = 0.87). In the wake of the Deepwater Horizon oil spill, this research lends support to the use of autonomous drifting profilers as a powerful tool for consideration in the design of an expanded and integrated observing network for

  12. First Autonomous Bio-Optical Profiling Float in the Gulf of Mexico Reveals Dynamic Biogeochemistry in Deep Waters

    PubMed Central

    Green, Rebecca E.; Bower, Amy S.; Lugo-Fernández, Alexis

    2014-01-01

    Profiling floats equipped with bio-optical sensors well complement ship-based and satellite ocean color measurements by providing highly-resolved time-series data on the vertical structure of biogeochemical processes in oceanic waters. This is the first study to employ an autonomous profiling (APEX) float in the Gulf of Mexico for measuring spatiotemporal variability in bio-optics and hydrography. During the 17-month deployment (July 2011 to December 2012), the float mission collected profiles of temperature, salinity, chlorophyll fluorescence, particulate backscattering (bbp), and colored dissolved organic matter (CDOM) fluorescence from the ocean surface to a depth of 1,500 m. Biogeochemical variability was characterized by distinct depth trends and local “hot spots”, including impacts from mesoscale processes associated with each of the water masses sampled, from ambient deep waters over the Florida Plain, into the Loop Current, up the Florida Canyon, and eventually into the Florida Straits. A deep chlorophyll maximum (DCM) occurred between 30 and 120 m, with the DCM depth significantly related to the unique density layer ρ = 1023.6 (R2 = 0.62). Particulate backscattering, bbp, demonstrated multiple peaks throughout the water column, including from phytoplankton, deep scattering layers, and resuspension. The bio-optical relationship developed between bbp and chlorophyll (R2 = 0.49) was compared to a global relationship and could significantly improve regional ocean-color algorithms. Photooxidation and autochthonous production contributed to CDOM distributions in the upper water column, whereas in deep water, CDOM behaved as a semi-conservative tracer of water masses, demonstrating a tight relationship with density (R2 = 0.87). In the wake of the Deepwater Horizon oil spill, this research lends support to the use of autonomous drifting profilers as a powerful tool for consideration in the design of an expanded and integrated observing network

  13. Wave excited motion of a body floating on water confined between two semi-infinite ice sheets

    NASA Astrophysics Data System (ADS)

    Ren, K.; Wu, G. X.; Thomas, G. A.

    2016-12-01

    The wave excited motion of a body floating on water confined between two semi-infinite ice sheets is investigated. The ice sheet is treated as an elastic thin plate and water is treated as an ideal and incompressible fluid. The linearized velocity potential theory is adopted in the frequency domain and problems are solved by the method of matched eigenfunctions expansion. The fluid domain is divided into sub-regions and in each sub-region the velocity potential is expanded into a series of eigenfunctions satisfying the governing equation and the boundary conditions on horizontal planes including the free surface and ice sheets. Matching is conducted at the interfaces of two neighbouring regions to ensure the continuity of the pressure and velocity, and the unknown coefficients in the expressions are obtained as a result. The behaviour of the added mass and damping coefficients of the floating body with the effect of the ice sheets and the excitation force are analysed. They are found to vary oscillatorily with the wave number, which is different from that for a floating body in the open sea. The motion of the body confined between ice sheets is investigated, in particular its resonant behaviour with extremely large motion found to be possible under certain conditions. Standing waves within the polynya are also observed.

  14. Efficient floating diffuse functions for accurate characterization of the surface-bound excess electrons in water cluster anions.

    PubMed

    Zhang, Changzhe; Bu, Yuxiang

    2017-01-25

    In this work, the effect of diffuse function types (atom-centered diffuse functions versus floating functions and s-type versus p-type diffuse functions) on the structures and properties of three representative water cluster anions featuring a surface-bound excess electron is studied and we find that an effective combination of such two kinds of diffuse functions can not only reduce the computational cost but also, most importantly, considerably improve the accuracy of results and even avoid incorrect predictions of spectra and the EE shape. Our results indicate that (a) simple augmentation of atom-centered diffuse functions is beneficial for the vertical detachment energy convergence, but it leads to very poor descriptions for the singly occupied molecular orbital (SOMO) and lowest unoccupied molecular orbital (LUMO) distributions of the water cluster anions featuring a surface-bound excess electron and thus a significant ultraviolet spectrum redshift; (b) the ghost-atom-based floating diffuse functions can not only contribute to accurate electronic calculations of the ground state but also avoid poor and even incorrect descriptions of the SOMO and the LUMO induced by excessive augmentation of atom-centered diffuse functions; (c) the floating functions can be realized by ghost atoms and their positions could be determined through an optimization routine along the dipole moment vector direction. In addition, both the s- and p-type floating functions are necessary to supplement in the basis set which are responsible for the ground (s-type character) and excited (p-type character) states of the surface-bound excess electron, respectively. The exponents of the diffuse functions should also be determined to make the diffuse functions cover the main region of the excess electron distribution. Note that excessive augmentation of such diffuse functions is redundant and even can lead to unreasonable LUMO characteristics.

  15. STS-46 MS PLC Hoffman floats in life raft during water egress training at JSC

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-46 Atlantis, Orbiter Vehicle (OV) 104, Mission Specialist (MS) and Payload Commander Jeffrey A. Hoffman floats in a one-person life raft during launch emergency egress (bailout) simulation conducted in JSC's Weightless Environment Training Facility (WETF) Bldg 29 pool. Hoffman, who has just tumbled out a side hatch mockup, waits for his life raft to fully inflate as a SCUBA-equipped diver looks on. The long cylindrical object in the foreground serves as a prop for the crew escape system (CES) pole. In the background MS Franklin R. Chang-Diaz floats in a fully inflated life raft.

  16. STS-46 MS PLC Hoffman floats in life raft during water egress training at JSC

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-46 Atlantis, Orbiter Vehicle (OV) 104, Mission Specialist (MS) and Payload Commander Jeffrey A. Hoffman floats in a one-person life raft during launch emergency egress (bailout) simulation conducted in JSC's Weightless Environment Training Facility (WETF) Bldg 29 pool. Hoffman, who has just tumbled out a side hatch mockup, waits for his life raft to fully inflate as a SCUBA-equipped diver looks on. The long cylindrical object in the foreground serves as a prop for the crew escape system (CES) pole. In the background MS Franklin R. Chang-Diaz floats in a fully inflated life raft.

  17. Use of Chironomidae (Diptera) Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies.

    PubMed

    Kranzfelder, Petra; Anderson, Alyssa M; Egan, Alexander T; Mazack, Jane E; Bouchard, R William; Rufer, Moriya M; Ferrington, Leonard C

    2015-07-24

    Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. Unfortunately, traditional benthic larval sampling methods, such as the dip-net, can be time-consuming and expensive. An alternative protocol involves collection of Chironomidae surface-floating pupal exuviae (SFPE). Chironomidae is a species-rich family of flies (Diptera) whose immature stages typically occur in aquatic habitats. Adult chironomids emerge from the water, leaving their pupal skins, or exuviae, floating on the water's surface. Exuviae often accumulate along banks or behind obstructions by action of the wind or water current, where they can be collected to assess chironomid diversity and richness. Chironomids can be used as important biological indicators, since some species are more tolerant to pollution than others. Therefore, the relative abundance and species composition of collected SFPE reflect changes in water quality. Here, methods associated with field collection, laboratory processing, slide mounting, and identification of chironomid SFPE are described in detail. Advantages of the SFPE method include minimal disturbance at a sampling area, efficient and economical sample collection and laboratory processing, ease of identification, applicability in nearly all aquatic environments, and a potentially more sensitive measure of ecosystem stress. Limitations include the inability to determine larval microhabitat use and inability to identify pupal exuviae to species if they have not been associated with adult males.

  18. Tank Tests to Show the Effect Rivet Heads on the Water Performance of a Seaplane-Float

    NASA Technical Reports Server (NTRS)

    Parkinson, J B

    1938-01-01

    A 1/3.5 full-sized model of a seaplane float constructed from lines supplied by the Bureau of Aeronautics, Navy Department, was tested first with smooth painted bottom surfaces and then with round-head rivets, plate laps, and keel plates fitted to simulate the actual bottom of a metal float. A percentage increase in water resistance caused by the added roughness was found to be from 5 to 20 percent at the hump speed and from 15 to 40 percent at high speeds. The effect of the roughness of the afterbody was found to be negligible except at high trims. The model data were extrapolated to full size by the usual method that assumes the forces to vary according to Froude's law and, in the case of the smooth model, by a method of separation that takes into account the effect of scale on the frictional resistance. It was concluded that the effect of rivet heads on the take-off performance of a relatively high-powered float seaplane is of little consequence, but it may be of greater importance in the case of more moderately powered flying boats.

  19. Tank Tests of the Effect of Rivet Heads, etc., on the Water Performance of a Seaplane Float, Special Report

    NASA Technical Reports Server (NTRS)

    Parkinson, J. B.; Robertson, J. B., Jr.

    1936-01-01

    A 1/3.5 full-size model of the Mark V float of the Bureau of Aeronautics, Navy Department, was tested in the NACA tank both with smooth painted bottom surfaces and with roundhead rivets, plate laps, and keel plates fitted to simulate the actual bottom of a metal float. The augmentation in water resistance due to the added roughness was found to be from 10-12% at the hum speed and from 12-14% at high speeds. The effect of the roughness of the afterbody was found to be negligible except at high trims. The model data were extrapolated to full size by the usual method which assumes the forces to vary according to Froude's law, and in the case of the smooth model by a method of separation that takes into account the effect of scale on the frictional resistance. It was concluded that the effect of rivet heads on the takeoff performance of a relatively high-powered float seaplane is of little consequence but that it may be of greater importance in the case of more moderately powered flying boats.

  20. Induced water condensation and bridge formation by electric fieldsin Atomic Force Microscopy

    SciTech Connect

    Sacha, G.M.; Verdaguer, A.; Salmeron, M.

    2006-02-22

    We present an analytical model that explains how in humidenvironments the electric field near a sharp tip enhances the formationof water meniscii and bridges between tip and sample. The predictions ofthe model are compared with experimental measurements of the criticaldistance where the field strength causes bridge formation.

  1. 18. Photocopy of photograph of WalpoleWestminster bridge at high water ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. Photocopy of photograph of Walpole-Westminster bridge at high water during flood of November, 1927; photograph from Walpole Historical Society scrapbook collection. View west: Walpole approach (railroad station and store) and Connecticut River at flood stage, November, 1927. - Walpole-Westminster Bridge, Spanning Connecticut River between Walpole, NH & Westminster, VT, Walpole, Cheshire County, NH

  2. Nanoscale, electric field-driven water bridges in vacuum gaps and lipid bilayers.

    PubMed

    Ho, Ming-Chak; Levine, Zachary A; Vernier, P Thomas

    2013-11-01

    Formation of a water bridge across the lipid bilayer is the first stage of pore formation in molecular dynamic (MD) simulations of electroporation, suggesting that the intrusion of individual water molecules into the membrane interior is the initiation event in a sequence that leads to the formation of a conductive membrane pore. To delineate more clearly the role of water in membrane permeabilization, we conducted extensive MD simulations of water bridge formation, stabilization, and collapse in palmitoyloleoylphosphatidylcholine bilayers and in water-vacuum-water systems, in which two groups of water molecules are separated by a 2.8 nm vacuum gap, a simple analog of a phospholipid bilayer. Certain features, such as the exponential decrease in water bridge initiation time with increased external electric field, are similar in both systems. Other features, such as the relationship between water bridge lifetime and the diameter of the water bridge, are quite different between the two systems. Data such as these contribute to a better and more quantitative understanding of the relative roles of water and lipid in membrane electropore creation and annihilation, facilitating a mechanism-driven development of electroporation protocols. These methods can be extended to more complex, heterogeneous systems that include membrane proteins and intracellular and extracellular membrane attachments, leading to more accurate models of living cells in electric fields.

  3. Spreading of Polar Water Masses into the Nordic Seas - Analyses of hydrographic measurements from Seagliders and Argo floats

    NASA Astrophysics Data System (ADS)

    Latarius, K.

    2016-02-01

    Hydrographic measurements from Seagliders and Argo-floats were analyzed with regard to the variation of freshwater in the western Nordic Seas. Fresh polar water masses and sea ice leave the Arctic Ocean through Fram Strait with the East Greenland Current. But it is still not clear how much of this water continues across the Greenland-Scotland-Ridge into the subpolar North Atlantic versus leakages into the deep western basins of the Nordic Seas. The amount of liquid freshwater is additionally rising on the way through the Nordic Seas due to ice melt. If it reaches the western basins (Greenland Sea Basin and Icelandic Plateau) the convection during winter will be damped by a surface layer of extremely light waters. This may also affect the overturning circulation. Seaglider sections with high spatial resolution are used to quantify the eddy exchange between the East Greenland Current and the Greenland Sea. Measurements from Argo floats provide information about the large-scale and long-term hydrographic development in the deep basins.

  4. Boring crustaceans damage polystyrene floats under docks polluting marine waters with microplastic.

    PubMed

    Davidson, Timothy M

    2012-09-01

    Boring isopods damage expanded polystyrene floats under docks and, in the process, expel copious numbers of microplastic particles. This paper describes the impacts of boring isopods in aquaculture facilities and docks, quantifies and discusses the implications of these microplastics, and tests if an alternate foam type prevents boring. Floats from aquaculture facilities and docks were heavily damaged by thousands of isopods and their burrows. Multiple sites in Asia, Australia, Panama, and the USA exhibited evidence of isopod damage. One isopod creates thousands of microplastic particles when excavating a burrow; colonies can expel millions of particles. Microplastics similar in size to these particles may facilitate the spread of non-native species or be ingested by organisms causing physical or toxicological harm. Extruded polystyrene inhibited boring, suggesting this foam may prevent damage in the field. These results reveal boring isopods cause widespread damage to docks and are a novel source of microplastic pollution.

  5. Offshore Floating Wind Turbine-driven Deep Sea Water Pumping for Combined Electrical Power and District Cooling

    NASA Astrophysics Data System (ADS)

    Sant, T.; Buhagiar, D.; Farrugia, R. N.

    2014-06-01

    A new concept utilising floating wind turbines to exploit the low temperatures of deep sea water for space cooling in buildings is presented. The approach is based on offshore hydraulic wind turbines pumping pressurised deep sea water to a centralised plant consisting of a hydro-electric power system coupled to a large-scale sea water-cooled air conditioning (AC) unit of an urban district cooling network. In order to investigate the potential advantages of this new concept over conventional technologies, a simplified model for performance simulation of a vapour compression AC unit was applied independently to three different systems, with the AC unit operating with (1) a constant flow of sea surface water, (2) a constant flow of sea water consisting of a mixture of surface sea water and deep sea water delivered by a single offshore hydraulic wind turbine and (3) an intermittent flow of deep sea water pumped by a single offshore hydraulic wind turbine. The analysis was based on one year of wind and ambient temperature data for the Central Mediterranean that is known for its deep waters, warm climate and relatively low wind speeds. The study confirmed that while the present concept is less efficient than conventional turbines utilising grid-connected electrical generators, a significant portion of the losses associated with the hydraulic transmission through the pipeline are offset by the extraction of cool deep sea water which reduces the electricity consumption of urban air-conditioning units.

  6. Floating microbial fuel cells as energy harvesters for signal transmission from natural water bodies

    NASA Astrophysics Data System (ADS)

    Schievano, Andrea; Colombo, Alessandra; Grattieri, Matteo; Trasatti, Stefano P.; Liberale, Alessandro; Tremolada, Paolo; Pino, Claudio; Cristiani, Pierangela

    2017-02-01

    A new type of floating microbial fuel cell (fMFC) was developed for power supply of remote environmental sensors and data transmission. Ten operating fMFCs generated a cell potential in the range 100-800 mV depending on the external resistance applied. Power production peaked around 3-3.5 mW (power density of 22-28 mW m-2 cathode) after about 20-30 days of start-up period. The average of daily electrical energy harvested ranged between 10 and 35 mWh/d. Long-term performances were ensured in the presence of dense rice plants (Oryza Sativa). A power management system, based on a step-up DC/DC converter and a low-power data transmission system via SIGFOX™ technology, have been set up for the fMFCs. The tested fMFCs systems allowed to: i) harvest produced energy, ii) supply electronic devices (intermittent LED-light and a buzzer); iii) transmit remote data at low speed (three message of 12 bites each, in 6 s). Several 'floating garden' MFCs were set in the context of demonstrative events at EXPO2015 world exposition held in Milan between May-October 2015. Some of the 'floating garden' MFCs were operating for more than one year.

  7. FAST TRACK COMMUNICATION: Water absorption dependent photoconductivity of a freestanding polymer bridge

    NASA Astrophysics Data System (ADS)

    Kim, Daeyoung; Choi, Jaewu

    2010-06-01

    The photo-response of a freestanding constricted polymeric solid-state bridge of water soluble sodium poly[2-(3-thienyl)-ethoxy-4-butylsulfonate] (SPTEBS) was studied as a function of water vapor pressure. The dark current dramatically increases with water vapor pressure higher than 12 Torr. Surprisingly, under light illumination, the short-circuit current of the polymeric solid-state bridge decreases with increasing water vapor pressure so that, above 12 Torr of water vapor pressure, the short-circuit current under the light illumination is even lower than the dark current. This negative photo-response of the polymeric solid-state bridge is attributed to the self-doping by hydration of the polymer and the de-doping, possibly the result of photo-induced desorption of adsorbed water molecules.

  8. Bridges over troubled waters: education and cognitive neuroscience.

    PubMed

    Ansari, Daniel; Coch, Donna

    2006-04-01

    Recently there has been growing interest in and debate about the relation between cognitive neuroscience and education. Our goal is to advance the debate beyond both recitation of potentially education-related cognitive neuroscience findings and the claim that a bridge between fields is chimerical. In an attempt to begin a dialogue about mechanisms among students, educators, researchers and practitioner-scientists, we propose that multiple bridges can be built to make connections between education and cognitive neuroscience, including teacher training, researcher training and collaboration. These bridges--concrete mechanisms that can advance the study of mind, brain and education--will benefit both educators and cognitive neuroscientists, who will gain new perspectives for posing and answering crucial questions about the learning brain.

  9. 9. LOADED CAR FLOAT AND TUG IN THE PROCESS OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. LOADED CAR FLOAT AND TUG IN THE PROCESS OF DOCKING AT BRIDGE NO. 11. LOOKING EAST. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

  10. Exploring Floating Concrete and Beam Design.

    ERIC Educational Resources Information Center

    Snell, Billie G.; Snell, Luke M.

    2002-01-01

    Presents two construction activities that address both state and federal science standards and encourage students to consider career options in mathematics and science. Includes floating concrete and paper bridge activities. (YDS)

  11. Exploring Floating Concrete and Beam Design.

    ERIC Educational Resources Information Center

    Snell, Billie G.; Snell, Luke M.

    2002-01-01

    Presents two construction activities that address both state and federal science standards and encourage students to consider career options in mathematics and science. Includes floating concrete and paper bridge activities. (YDS)

  12. Floating Versus Sinking

    NASA Astrophysics Data System (ADS)

    Vella, Dominic

    2015-01-01

    Small objects that are more dense than water may still float at the air-water interface because of surface tension. Whether this is possible depends not only on the density and size of the object, but also on its shape and surface properties, whether other objects are nearby, and how gently the object is placed at the interface. This review surveys recent work to quantify when objects can float and when they must sink. Much interest in this area has been driven by studies of the adaptations of water-walking insects to life at interfaces. I therefore discuss these results in the context of this and other applications.

  13. Bridge over Troubled Waters: Training for Department Level Supervisors.

    ERIC Educational Resources Information Center

    Cook, Gillian E.; Skipper, Barbara L.

    A clinical supervision training program has provided department level coordinators with support in their role as a bridge between administrators and teachers in six high schools and nine middle schools in a San Antonio, Texas, school district. This paper identifies major characteristics of the training program's model, describes the program, and…

  14. Bridge over Troubled Waters: Training for Department Level Supervisors.

    ERIC Educational Resources Information Center

    Cook, Gillian E.; Skipper, Barbara L.

    A clinical supervision training program has provided department level coordinators with support in their role as a bridge between administrators and teachers in six high schools and nine middle schools in a San Antonio, Texas, school district. This paper identifies major characteristics of the training program's model, describes the program, and…

  15. STS-32 MS Dunbar wearing LES floats in life raft during water egress training

    NASA Image and Video Library

    1989-11-15

    STS-32 Mission Specialist (MS) Bonnie J. Dunbar, wearing a launch and entry suit (LES) and lauch and entry helmet (LEH), in a single-occupant (one man) lift raft enlists the aid of two SCUBA-equipped divers as she floats in 25 ft deep pool located in JSC's Weightless Environment Training Facility (WETF) Bldg 29. During the exercises the crew practiced the procedures to follow in the event of an emergency aboard the Space Shuttle and familiarized themselves with post-Challenger pole system of emergency egress.

  16. LNAPLs do not Always Float: An Example Case of a Viscous LNAPL under Variable Water Table Conditions

    SciTech Connect

    Oostrom, Mart; Hofstee , C; Wietsma, Thomas W.

    2006-03-20

    An intermediate-scale experiment was conducted to investigate the behavior of a viscous LNAPL under variable water table conditions. Two LNAPL volumes were released from a small source zone on top of the flow cell into a partly saturated, homogeneously packed porous medium. Following a 30-day redistribution period, the water table was increased 0.5 m in 50 minutes. After the water table rise, LNAPL behavior was monitored for an additional 45 days. Fluid saturation scans were obtained periodically with a fully automated dual-energy gamma radiation system. Results show that both spills follow similar paths downwards. LNAPL drainage from the unsaturated zone was relatively slow and a considerable residual LNAPL saturation was observed after 30 days of drainage. Most of the mobile LNAPL moved into the capillary fringe during this period. After the water table rise, LNAPL moved up in a delayed fashion. After 45 days, the LNAPL has moved up only approximately 0.2 m. Since the LNAPL has only moved up a limited amount, nonwetting fluid entrapment was also limited. The experiment was simulated using the STOMP multifluid flow simulator. A comparison indicates that the simulator is able to predict the observed phenomena well, including residual saturation formation in the vadose zone, and limited upward LNAPL movement after the water table rise. The results of this experiment show that viscous mobile LNAPL, subject to variable water table conditions, does not necessarily float on the water table and may not appear in an observation well.

  17. The annual cycle of nitrate and net community production in surface waters of the Southern Ocean observed with SOCCOM profiling floats

    NASA Astrophysics Data System (ADS)

    Johnson, K. S.; Plant, J. N.; Sakamoto, C.; Coletti, L. J.; Sarmiento, J. L.; Riser, S.; Talley, L. D.

    2016-12-01

    Sixty profiling floats with ISUS and SUNA nitrate sensors have been deployed in the Southern Ocean (south of 30 degrees S) as part of the SOCCOM (Southern Ocean Carbon and Climate Observations and Modeling) program and earlier efforts. These floats have produced detailed records of the annual cycle of nitrate concentration throughout the region from the surface to depths near 2000 m. In surface waters, there are clear cycles in nitrate concentration that result from uptake of nitrate during austral spring and summer. These changes in nitrate concentration were used to compute the annual net community production over this region. NCP was computed using a simplified version of the approach detailed by Plant et al. (2016, Global Biogeochemical Cycles, 30, 859-879, DOI: 10.1002/2015GB005349). At the time the abstract was written 41 complete annual cycles were available from floats deployed before the austral summer of 2015/2016. After filtering the data to remove floats that crossed distinct frontal boundaries, floats with other anomalies, and floats in sub-tropical waters, 23 cycles were available. A preliminary assessment of the data yields an NCP of 2.8 +/- 0.95 (1 SD) mol C/m2/y after integrating to 100 m depth and converting nitrate uptake to carbon using the Redfield ratio. This preliminary assessment ignores vertical transport across the nitracline and is, therefore, a minimum estimate. The number of cycles available for analysis will increase rapidly, as 32 of the floats were deployed in the austral summer of 2015/2016 and have not yet been analyzed.

  18. Liquid-phase microextraction by solidification of floating organic microdrop and GC-MS detection of trihalomethanes in drinking water.

    PubMed

    Farahani, Hadi; Norouzi, Parviz; Dinarvand, Rassoul; Ganjali, Mohammad Reza

    2009-01-01

    A simple and sensitive methodology based on liquid-phase microextraction (LPME) followed by GC-MS, was developed for the determination of trihalomethanes (THMs) in drinking water. A microdrop of organic solvent was floated on the surface of the aqueous sample and it was agitated for a desired time. Then, the sample vial was cooled by inserting it into an ice bath for 4 min. The solidified solvent was transferred into a suitable vial and immediately melted. The extract was directly injected into the GC. Microextraction efficiency factors were investigated and optimized: 7 muL 1-undecanol microdrop exposed for 15 min floated on the surface of a 10.0 mL aqueous sample with the temperature of 60 degrees C containing 3 M of NaCl and stirred at 750 rpm. Under the selected conditions, enrichment factors (EFs) up to 482-fold, LOD of 0.03-0.08 mug/L (S/N = 3) and dynamic linear ranges of 0.10-100 mug/L were obtained. A reasonable repeatability (RSD < 8.6%, n = 8) with satisfactory linearity (r(2) greater, not dbl equals 0.9947) of results illustrated a good performance of the present method. The protocol proved to be rapid, cost-effective, and is a green procedure for the screening purposes.

  19. Biotransformation of arsenite and bacterial aox activity in drinking water produced from surface water of floating houses: Arsenic contamination in Cambodia.

    PubMed

    Chang, Jin-Soo

    2015-11-01

    The potential arsenite bioteansformation activity of arsenic was investigated by examining bacterial arsenic arsenite-oxidizing gene such as aoxS, aoxR, aoxA, aoxB, aoxC, and aoxD in high arsenic-contaminated drinking water produced from the surface water of floating houses. There is a biogeochemical cycle of activity involving arsenite oxidase aox system and the ars (arsenic resistance system) gene operon and aoxR leader gene activity in Alcaligenes faecalis SRR-11 and aoxS leader gene activity in Achromobacter xylosoxidans TSL-66. Batch experiments showed that SRR-11 and TSL-66 completely oxidized 1 mM of As (III) to As (V) within 35-40 h. The leaders of aoxS and aoxR are important for gene activity, and their effects in arsenic bioremediation and mobility in natural water has a significant ecological role because it allows arsenite oxidase in bacteria to control the biogeochemical cycle of arsenic-contaminated drinking water produced from surface water of floating houses.

  20. A direct-dynamics study of proton transfer through water bridges in guanine and 7-azaindole

    NASA Astrophysics Data System (ADS)

    Smedarchina, Zorka; Siebrand, Willem; Fernández-Ramos, Antonio; Gorb, Leonid; Leszczynski, Jerzy

    2000-01-01

    To evaluate the efficiency of bridges of water molecules as proton conduits, multidimensional ab initio proton transfer rate constants are reported for complexes of guanine and 7-azaindole with one and two water molecules. These water molecules form hydrogen-bonded bridges between functional groups involved in tautomerization via proton transfer and catalyze this transfer. Structures and energies of the relevant stationary configurations are optimized at the second-order Møller-Plesset level and vibrational force fields are evaluated at the Hartree-Fock level. The proton transfer rate constants, calculated with the instanton method, show the effect of the structure and strength of the hydrogen bonds, reflected in couplings between the tunneling mode and the other vibrations of the complexes. The results indicate that strongly hydrogen-bonded, strain-free water bridges can serve as very efficient proton conduits.

  1. Atmospheric exchange of carbon dioxide and methane of a small water body and a floating mat in the Luther Marsh peatland, Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Burger, Magdalena; Berger, Sina; Blodau, Christian

    2015-04-01

    Recent investigations have suggested that small water bodies cover larger areas in northern peatlands than previously assumed. Their role in the carbon cycle and gas exchange rates are poorly constrained so far. To address this issue we measured CO2 and CH4 fluxes on a small water body (ca. 700 m2) and the surrounding floating mat in the Luther Marsh peatland in Ontario, Canada from July to September 2014. To this end we used closed chambers combined with a portable Los Gatos high-resolution trace gas analyzer at different water depths and distances from the shore on the pond and with different dominating plant types on the floating mat surrounding the pond. In addition, CO2 concentrations were recorded in high temporal resolution using an infrared sensor system during selected periods. Air and water temperature, humidity and temperature of the floating mat, wind speed and direction, photosynthetically active radiation, air pressure and relative humidity were also recorded as auxiliary data at the study site. The results show that pond and floating mat were sources of methane throughout the whole measuring period. Methane emissions via the ebullition pathway occurred predominantly near the shore and on the floating mat. During the daytime measurements the floating mat acted as a net sink and the pond as a net source of CO2. The dynamics of CO2 exchange was also strongly time dependent, as CO2 emissions from the pond strongly increased after mid-August. This suggests that photosynthesis was more affected by seasonal decline than respiration process in the pond and that the allochthonous component of the CO2 flux increased in relative importance towards fall.

  2. Force exerted by a nanoscale capillary water bridge between two planar substrates.

    PubMed

    Valenzuela, Gerson E; Saavedra, Jorge H; Rozas, Roberto E; Toledo, Pedro G

    2016-04-28

    Molecular dynamics simulation of a nanoscale capillary water bridge between two planar substrates is used to determine the resulting force between the substrates without arbitrariness regarding geometry and location of the free surface of the bridge. The substrates are moderately hydrophilic. The force changes continuously as the separation between the substrates changes except for small gaps where it becomes discontinuous because the bridge is unable to adopt stable configurations at any distance apart. Further exploration of the bridge and the force as the substrates approach each other reveals an underlying oscillatory force with an increasing repulsive component at separation distances equivalent to few water molecules. According to the average number of hydrogen bonds per water molecule (HBN), at very small gap sizes, water molecules which are very close to the surfaces are unable to maximize HBN thus contributing to the repulsive force. Our simulation results of force versus gap size agree with calculations based on other methods, some very different, and also reproduce the typical magnitude of the experimental force. Finally, a macroscopic force balance correctly describes the force-distance curve except for bridges constituted of water layers only.

  3. Layers of air in the water beneath the floating fern Salvinia are exposed to fluctuations in pressure.

    PubMed

    Mayser, Matthias J; Barthlott, Wilhelm

    2014-12-01

    Superhydrophobic, hierarchically structured, technical surfaces (Lotus-effect) are of high scientific and economic interest because of their remarkable properties. Recently, the immense potential of air-retaining superhydrophobic surfaces, for example, for low-friction transport of fluids and drag-reducing coatings of ships has begun to be explored. A major problem of superhydrophobic surfaces mimicking the Lotus-effect is the limited persistence of the air retained, especially under rough conditions of flow. However, there are a variety of floating or diving plant and animal species that possess air-retaining surfaces optimized for durable water-repellency (Salvinia-effect). Especially floating ferns of the genus Salvinia have evolved superhydrophobic surfaces capable of maintaining layers of air for months. Apart from maintaining stability under water, the layer of air has to withstand the stresses of water pressure (up to 2.5 bars). Both of these aspects have an application to create permanent air layers on ships' hulls. We investigated the effect of pressure on air layers in a pressure cell and exposed the air layer to pressures of up to 6 bars. We investigated the suppression of the air layer at increasing pressures as well as its restoration during decreases in pressure. Three of the four examined Salvinia species are capable of maintaining air layers at pressures relevant to the conditions applying to ships' hulls. High volumes of air per surface area are advantageous for retaining at least a partial Cassie-Baxter-state under pressure, which also helps in restoring the air layer after depressurization. Closed-loop structures such as the baskets at the top of the "egg-beater hairs" (see main text) also help return the air layer to its original level at the tip of the hairs by trapping air bubbles.

  4. Stools - floating

    MedlinePlus

    ... absorption of nutrients ( malabsorption ) or too much gas (flatulence). Considerations Most causes of floating stools are harmless. ... Elsevier Saunders; 2016:chap 140. Read More Gas - flatulence Malabsorption Review Date 5/11/2016 Updated by: ...

  5. Bridging Water Resources Policy and Environmental Engineering in the Classroom at Cornell University

    NASA Astrophysics Data System (ADS)

    Walter, M. T.; Shaw, S. B.; Seifert, S.; Schwarz, T.

    2006-12-01

    Current university undergraduate students in environmental sciences and engineering are the next generation of environmental protection practitioners. Recognizing this, Cornell's Biological and Environmental Engineering department has developed a popular class, Watershed Engineering (BEE 473), specifically designed to bridge the too-common gap between water resources policy and state-of-art science and technology. Weekly homework assignments are to design real-life solutions to actual water resources problems, often with the objective of applying storm water policies to local situations. Where appropriate, usually in conjunction with recent amendments to the Federal Clean Water Act, this course introduces water resource protection tools and concepts developed in the Cornell Soil and Water Lab. Here we present several examples of how we build bridges between university classrooms and the complex world of water resources policy.

  6. Temporal and spatial distribution of floating objects in coastal waters of central-southern Chile and Patagonian fjords

    NASA Astrophysics Data System (ADS)

    Hinojosa, Iván A.; Rivadeneira, Marcelo M.; Thiel, Martin

    2011-03-01

    Floating objects are suggested to be the principal vector for the transport and dispersal of marine invertebrates with direct development as well as catalysts for carbon and nutrient recycling in accumulation areas. The first step in identifying the ecological relevance of floating objects in a specific area is to identify their spatio-temporal distribution. We evaluated the composition, abundance, distribution, and temporal variability of floating objects along the continental coast of central-southern Chile (33-42°S) and the Patagonian fjords (42-50°S) using ship surveys conducted in austral winter (July/August) and spring (November) of the years 2002-2005 and 2008. Potential sources of floating items were identified with the aid of publicly available databases and scientific reports. We found three main types of floating objects, namely floating marine debris (mainly plastic objects and Styrofoam), wood (trunks and branches), and floating kelps ( Macrocystis pyrifera and Durvillaea antarctica). Floating marine debris were abundant along most of the examined transects, with markedly lower abundances toward the southern fjord areas. Floating marine debris abundances generally corresponded to the distribution of human activities, and were highest in the Interior Sea of Chiloé, where aquaculture activities are intense. Floating wood appeared sporadically in the study area, often close to the main rivers. In accordance with seasonal river run-off, wood was more abundant along the continental coast in winter (rainy season) and in the Patagonian fjords during the spring surveys (snow melt). Densities of the two floating kelp species were similar along the continental coast, without a clear seasonal pattern. M. pyrifera densities increased towards the south, peaking in the Patagonian fjords, where it was dominant over D. antarctica. Densities of M. pyrifera in the Patagonian fjords were highest in spring. Correlation analyses between the abundances of floating

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

    NASA Astrophysics Data System (ADS)

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

    2017-06-01

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

  8. Attraction of Two Floating Spheres at a Viscous Oil-Water Interface

    NASA Astrophysics Data System (ADS)

    Dani, Archit; Keiser, Geoff; Yeganeh, Mohsen; Maldarelli, Charles

    2014-03-01

    The aggregation rate of floating particles at a fluid/fluid interface by capillary forces has drawn significant interest. This 2D phenomenon plays a critical role in self-assembly arrangement relevant to pollination processes in biological contexts, the formation of dense particle laden interfaces for stabilizing emulsions in colloid science and in the bottom up assembly of materials in nanotechnologies. We present the first experiments on the merging of two Teflon particles at an interface between a mineral oil and an aqueous phase for a series of particle pairs, interfacial tension and oil viscosity. The separation distance as a function of time and pair aggregation time are both measured by optically following the movement of the particles. The experimental results are in excellent agreement with our theoretical formulation in which a drag correction accounts for the variation in particle depth of immersion.

  9. Peptide salt bridge stability: From gas phase via microhydration to bulk water simulations

    NASA Astrophysics Data System (ADS)

    Pluhařová, Eva; Marsalek, Ondrej; Schmidt, Burkhard; Jungwirth, Pavel

    2012-11-01

    The salt bridge formation and stability in the terminated lysine-glutamate dipeptide is investigated in water clusters of increasing size up to the limit of bulk water. Proton transfer dynamics between the acidic and basic side chains is described by DFT-based Born-Oppenheimer molecular dynamics simulations. While the desolvated peptide prefers to be in its neutral state, already the addition of a single water molecule can trigger proton transfer from the glutamate side chain to the lysine side chain, leading to a zwitterionic salt bridge state. Upon adding more water molecules we find that stabilization of the zwitterionic state critically depends on the number of hydrogen bonds between side chain termini, the water molecules, and the peptidic backbone. Employing classical molecular dynamics simulations for larger clusters, we observed that the salt bridge is weakened upon additional hydration. Consequently, long-lived solvent shared ion pairs are observed for about 30 water molecules while solvent separated ion pairs are found when at least 40 or more water molecules hydrate the dipeptide. These results have implications for the formation and stability of salt bridges at partially dehydrated surfaces of aqueous proteins.

  10. Treatment performance of artificial floating reed beds in an experimental mesocosm to improve the water quality of river Kshipra.

    PubMed

    Billore, S K; Prashant; Sharma, J K

    2009-01-01

    The discharge of untreated wastewater in River Kshipra had brought annual average of BOD, TKN and TS levels up to 39 mg/l, 38 mg/l and 781 mg/l respectively in the study area. Treatment performance by Artificial Floating Reed Beds (AFRB) was evaluated for removal efficiency of TS, NH4-N, NO3-N, TKN and BOD from river water, initially, under a pilot scale by an AFRB of size 200 m2 planted with local reed grass, Phragmites karka, in the part of River Kshipra at the confluence with meeting point of a wastewater stream. The system performance was recorded as 43% reduction in TS, 38% reduction in TKN and 39% BOD reduction. The experimental AFRBs were buoyant structure planted with reed grass, each unit had a rectangular size and covered an effective surface area of 2 m2. The experiment with the mesocosms with treatment of River water resulted that AFRB was reducing pollution load by 55-60% of TS, 45-55% of NH4-N, 33-45% of NO3-N, 45-50% of TKN and 40-50% of BOD. AFRB may be recommended as an in-situ, eco-friendly river water treatment structures for small shallow, slow flowing (or slightly stagnant) water bodies.

  11. Quantum Calculations on Salt Bridges with Water: Potentials, Structure, and Properties

    SciTech Connect

    Liao, Sing; Green, Michael E.

    2011-01-01

    Salt bridges are electrostatic links between acidic and basic amino acids in a protein; quantum calculations are used here to determine the energetics and other properties of one form of these species, in the presence of water molecules. The acidic groups are carboxylic acids (aspartic and glutamic acids); proteins have two bases with pK above physiological pH: one, arginine, with a guanidinium basic group, the other lysine, which is a primary amine. Only arginine is modeled here, by ethyl guanidinium, while propionic acid is used as a model for either carboxylic acid. The salt bridges are accompanied by 0-12 water molecules; for each of the 13 systems, the energy-bond distance relation, natural bond orbitals (NBO), frequency calculations allowing thermodynamic corrections to room temperature, and dielectric constant dependence, were all calculated. The water molecules were found to arrange themselves in hydrogen bonded rings anchored to the oxygens of the salt bridge components. This was not surprising in itself, but it was found that the rings lead to a periodicity in the energy, and to a 'water addition' rule. The latter shows that the initial rings, with four oxygen atoms, become five member rings when an additional water molecule becomes available, with the additional water filling in at the bond with the lowest Wiberg index, as calculated using NBO. The dielectric constant dependence is the expected hyperbola, and the fit of the energy to the inverse dielectric constant is determined. There is an energy periodicity related to ring formation upon addition of water molecules. When 10 water molecules have been added, all spaces near the salt bridge are filled, completing the first hydration shell, and a second shell starts to form. The potentials associated with salt bridges depend on their hydration, and potentials assigned without regard to local hydration are likely to cause errors as large as or larger than kBT, thus suggesting a serious problem if these

  12. Sub-canopy evapotranspiration from floating vegetation and open water in a swamp forest

    USDA-ARS?s Scientific Manuscript database

    Among previous studies, there are large discrepancies in the difference between evapotranspiration from wetland vegetation and evaporation from open water. In this study, we investigate evapotranspiration differences between water and vegetation in a scenario that has otherwise not been extensively ...

  13. Preventing Pollution to Local Waters, Bay; Preserving Historic Natural Bridge in Virginia

    EPA Pesticide Factsheets

    In helping to preserve one of the oldest tourist destinations in the country – a spectacular natural land bridge in Virginia – EPA funding is protecting the surrounding land from development that would have impacted local waters and the Chesapeake Bay.

  14. Bridge over troubled waters: A Synthesis Session to connect ...

    EPA Pesticide Factsheets

    Lack of access to relevant scientific data has limited decision makers from incorporating scientific information into their management and policy schemes. Yet, there is increasing interest among decision makers and scientists to integrate coastal and marine science into the policy and management process. Strategies designed to build communication between decision makers and scientists can be an effective means to disseminate and/or generate policy relevant scientific information. Here researchers develop, test, and present a workshop model designed to bridge the gap between coastal and marine decision makers and scientists. Researchers identify successful components of such a workshop as well as areas for improvement and recommendations to design and conduct similar workshops in the future. This novel workshop format can be used in other fora to effectively connect decision makers and scientists, and to initiate an iterative process to generate and transfer policy relevant scientific information into evidence-based decisions, an important element in protecting coastal and marine resources. In this paper we develop and present a model for increasing collaboration between scientists and decision makers to promote evidence based decisions. Successes and areas for improvement in the tested model are discussed. This novel workshop model is intended to build and sustain connections, with the ultimate goal of creating better policy and management practices. In a recent

  15. Bridge over troubled waters: A Synthesis Session to connect ...

    EPA Pesticide Factsheets

    Lack of access to relevant scientific data has limited decision makers from incorporating scientific information into their management and policy schemes. Yet, there is increasing interest among decision makers and scientists to integrate coastal and marine science into the policy and management process. Strategies designed to build communication between decision makers and scientists can be an effective means to disseminate and/or generate policy relevant scientific information. Here researchers develop, test, and present a workshop model designed to bridge the gap between coastal and marine decision makers and scientists. Researchers identify successful components of such a workshop as well as areas for improvement and recommendations to design and conduct similar workshops in the future. This novel workshop format can be used in other fora to effectively connect decision makers and scientists, and to initiate an iterative process to generate and transfer policy relevant scientific information into evidence-based decisions, an important element in protecting coastal and marine resources. In this paper we develop and present a model for increasing collaboration between scientists and decision makers to promote evidence based decisions. Successes and areas for improvement in the tested model are discussed. This novel workshop model is intended to build and sustain connections, with the ultimate goal of creating better policy and management practices. In a recent

  16. Water intrusions and particle signatures in the Black Sea: a Biogeochemical-Argo float investigation

    NASA Astrophysics Data System (ADS)

    Stanev, Emil Vassilev; Grayek, Sebastian; Claustre, Hervé; Schmechtig, Chaterine; Poteau, Antoine

    2017-07-01

    Continuous observations during 3 years with a vertical resolution of 1 dbar from two Bio-Argo floats in the Black Sea that were equipped with oxygen optodes, chlorophyll fluorometers, and backscattering sensors are analyzed. The particle backscattering coefficient, b bp provides a proxy for the concentration of suspended particles. The observations clearly identify thermal and b bp intrusions down to 700-800 m in the Bosporus inflow area. In this area, b bp is more than five times larger than elsewhere, which could indicate bacterial abundance and possible biological involvement in the precipitation of Mn-containing particles. The b bp anomalies become much shallower than the temperature anomalies with increasing distance to the east of the strait. Their maxima are located between the onset of the suboxic zone and the upper part of the anoxic layer. Unlike well-known intrusions that are caused by inflow, open ocean intrusions are shallower and often characterized by multiple layers of backscatter maxima with thicknesses of only 15-20 m. The ratio between backscattering coefficients measured at two wavelengths, which gives a proxy for particle size, shows that the relative amount of larger size particles in the anoxic layer increases with depth. The particle concentrations and their size distribution display different vertical variability, which indicates the complex transformation of biological matter. The lower concentration of particles and lower chlorophyll-a during the extremely warm 2016 reveals an overall positive correlation between the two properties. The trends in the particle backscattering coefficient in the suboxic zone during 2013-2016 could indirectly reveal a biogeochemical response to temperature changes.

  17. Water intrusions and particle signatures in the Black Sea: a Biogeochemical-Argo float investigation

    NASA Astrophysics Data System (ADS)

    Stanev, Emil Vassilev; Grayek, Sebastian; Claustre, Hervé; Schmechtig, Chaterine; Poteau, Antoine

    2017-09-01

    Continuous observations during 3 years with a vertical resolution of 1 dbar from two Bio-Argo floats in the Black Sea that were equipped with oxygen optodes, chlorophyll fluorometers, and backscattering sensors are analyzed. The particle backscattering coefficient, b bp provides a proxy for the concentration of suspended particles. The observations clearly identify thermal and b bp intrusions down to 700-800 m in the Bosporus inflow area. In this area, b bp is more than five times larger than elsewhere, which could indicate bacterial abundance and possible biological involvement in the precipitation of Mn-containing particles. The b bp anomalies become much shallower than the temperature anomalies with increasing distance to the east of the strait. Their maxima are located between the onset of the suboxic zone and the upper part of the anoxic layer. Unlike well-known intrusions that are caused by inflow, open ocean intrusions are shallower and often characterized by multiple layers of backscatter maxima with thicknesses of only 15-20 m. The ratio between backscattering coefficients measured at two wavelengths, which gives a proxy for particle size, shows that the relative amount of larger size particles in the anoxic layer increases with depth. The particle concentrations and their size distribution display different vertical variability, which indicates the complex transformation of biological matter. The lower concentration of particles and lower chlorophyll-a during the extremely warm 2016 reveals an overall positive correlation between the two properties. The trends in the particle backscattering coefficient in the suboxic zone during 2013-2016 could indirectly reveal a biogeochemical response to temperature changes.

  18. Theoretical model for diffusive greenhouse gas fluxes estimation across water-air interfaces measured with the static floating chamber method

    NASA Astrophysics Data System (ADS)

    Xiao, Shangbin; Wang, Chenghao; Wilkinson, Richard Jeremy; Liu, Defu; Zhang, Cheng; Xu, Wennian; Yang, Zhengjian; Wang, Yuchun; Lei, Dan

    2016-07-01

    Aquatic systems are sources of greenhouse gases on different scales, however the uncertainty of gas fluxes estimated using popular methods are not well defined. Here we show that greenhouse gas fluxes across the air-water interface of seas and inland waters are significantly underestimated by the currently used static floating chamber (SFC) method. We found that the SFC CH4 flux calculated with the popular linear regression (LR) on changes of gas concentration over time only accounts for 54.75% and 35.77% of the corresponding real gas flux when the monitoring periods are 30 and 60 min respectively based on the theoretical model and experimental measurements. Our results do manifest that nonlinear regression models can improve gas flux estimations, while the exponential regression (ER) model can give the best estimations which are close to true values when compared to LR. However, the quadratic regression model is proved to be inappropriate for long time measurements and those aquatic systems with high gas emission rate. The greenhouse gases effluxes emitted from aquatic systems may be much more than those reported previously, and models on future scenarios of global climate changes should be adjusted accordingly.

  19. A co-beneficial system using aquatic plants: bioethanol production from free-floating aquatic plants used for water purification.

    PubMed

    Soda, S; Mishima, D; Inoue, D; Ike, M

    2013-01-01

    A co-beneficial system using constructed wetlands (CWs) planted with aquatic plants is proposed for bioethanol production and nutrient removal from wastewater. The potential for bioethanol production from aquatic plant biomass was experimentally evaluated. Water hyacinth and water lettuce were selected because of their high growth rates and easy harvestability attributable to their free-floating vegetation form. The alkaline/oxidative pretreatment was selected for improving enzymatic hydrolysis of the aquatic plants. Ethanol was produced with yields of 0.14-0.17 g-ethanol/ g-biomass in a simultaneous saccharification and fermentation mode using a recombinant Escherichia coli strain or a typical yeast strain Saccharomyces cerevisiae. Subsequently, the combined benefits of the CWs planted with the aquatic plants for bioethanol production and nutrient removal were theoretically estimated. For treating domestic wastewater at 1,100 m(3)/d, it was inferred that the anoxic-oxic activated sludge process consumes energy at 3,200 MJ/d, whereas the conventional activated sludge process followed by the CW consumes only 1,800 MJ/d with ethanol production at 115 MJ/d.

  20. 33 CFR 144.01-1 - Life floats.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Life floats. 144.01-1 Section 144... CONTINENTAL SHELF ACTIVITIES LIFESAVING APPLIANCES Manned Platforms § 144.01-1 Life floats. Each manned platform shall be provided with at least two approved life floats. The life floats shall have...

  1. 33 CFR 144.01-1 - Life floats.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Life floats. 144.01-1 Section 144... CONTINENTAL SHELF ACTIVITIES LIFESAVING APPLIANCES Manned Platforms § 144.01-1 Life floats. Each manned platform shall be provided with at least two approved life floats. The life floats shall have...

  2. 33 CFR 144.01-1 - Life floats.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Life floats. 144.01-1 Section 144... CONTINENTAL SHELF ACTIVITIES LIFESAVING APPLIANCES Manned Platforms § 144.01-1 Life floats. Each manned platform shall be provided with at least two approved life floats. The life floats shall have...

  3. 33 CFR 144.01-1 - Life floats.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Life floats. 144.01-1 Section 144... CONTINENTAL SHELF ACTIVITIES LIFESAVING APPLIANCES Manned Platforms § 144.01-1 Life floats. Each manned platform shall be provided with at least two approved life floats. The life floats shall have...

  4. Municipal landfill leachate treatment for metal removal using water hyacinth in a floating aquatic system.

    PubMed

    El-Gendy, A S; Biswas, N; Bewtra, J K

    2006-09-01

    Experiments were carried out to investigate the ability of water hyacinth (Eichhornia crassipes) to remove five heavy metals (cadmium, chromium, copper, nickel, and lead) commonly found in leachate. All experiments were conducted in batch reactors in a greenhouse. It was found that living biomass of water hyacinth was a good accumulator for copper, chromium, and cadmium. The plants accumulated copper, chromium, and cadmium up to 0.96, 0.83, and 0.50%, respectively, of their dry root mass. However, lead and nickel were poorly accumulated in water hyacinth. Also, nonliving biomass of water hyacinth dry roots showed ability to accumulate all metals, except Cr(VI), which was added in anionic form. The highest total metal sorption by nonliving dry water hyacinth roots was found to take place at pH 6.4. The current research demonstrates the potential of using water hyacinth for the treatment of landfill leachate containing heavy metals.

  5. Buoyant force and sinking conditions of a hydrophobic thin rod floating on water.

    PubMed

    Liu, Jian-Lin; Feng, Xi-Qiao; Wang, Gang-Feng

    2007-12-01

    Owing to the superhydrophobicity of their legs, such creatures as water striders and fisher spiders can stand effortlessly, walk and jump quickly on water. Directed toward understanding their superior repellency ability, we consider hydrophobic thin rods of several representative cross sections pressing a water surface. First, the shape function of the meniscus surrounding a circular rod is solved analytically, and thereby the maximal buoyant force is derived as a function of the Young's contact angle and the rod radius. Then we discuss the critical conditions for a rod to sink into water, including the maximal volume condition and the meniscus-contact condition. Furthermore, we study the sinking conditions and the maximal buoyant forces of hydrophobic long rods with elliptical, triangular, or hexagonal cross-section shapes. The theoretical solutions are quantitatively consistent with existing experimental and numerical results. Finally, the optimized structures of water strider legs are analyzed to elucidate why they can achieve a very big buoyant force on water.

  6. STS-35 crewmembers watch a sphere of water float on OV-102's middeck

    NASA Image and Video Library

    1990-12-10

    STS035-15-035 (2-10 Dec 1990) --- STS-35 crewmembers perform a microgravity experiment using their drinking water while on the middeck of Columbia, Orbiter Vehicle (OV) 102. Mission Specialist (MS) Jeffrey A. Hoffman (left) has released some water from a drinking container which he holds in his hand. MS John M. Lounge (wearing glasses, center) and Payload Specialist Samuel T. Durrance along with Hoffman study the changing shape and movement of the sphere of water.

  7. STS-35 crewmembers watch a sphere of water float on OV-102's middeck

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-35 crewmembers perform a microgravity experiment using their drinking water while on the middeck of Columbia, Orbiter Vehicle (OV) 102. Mission Specialist (MS) Jeffrey A. Hoffman (left) has released some water from a drinking container which he holds in his hand. MS John M. Lounge (wearing glasses, center) and Payload Specialist Samuel T. Durrance along with Hoffman study the changing shape and movement of the sphere of water.

  8. The impact of water-floating and high-intensity exercise on rat's HPA axis and interleukins concentrations.

    PubMed

    Wang, Jian; Zhao, Dan; Li, Jie; Wang, Guohong; Hu, Lanping; Shao, Jiaging; Gu, Ping; Du, Hong; Wang, Yangt

    2012-09-01

    Our studies explore the changes of blood corticosterone (CORT), adrenocorticotropic hormone (ACTH), interleukin (IL)-1β, IL-2, IL-6 concentrations and the pituitary ACTH expression in rats after water floating in the presence or absence of following high-intensity exercise. The rats were randomly assigned into three groups. Group A served as control; Group B received 180 minutes water floating and psychological (fear) stimulation; Group C received the same treatment as Group B in addition and 120-minutes non-stop running. Compared to Group A, Group B showed a significant increase of IL-2 (19.91 ± 2.52 vs. 13.09 ± 3.13 ng/ml, P < 0.05), and IL-6 (0.18 ± 0.08 vs. 0.12 ± 0.05 ng/ml, P < 0.05); Group C demonstrated a significant increase of CORT (977.22 ± 207.36 ng/ml vs. 434.58 ± 110.45 ng/ml, P <0.01) and IL-1β (0.21 ± 0.04 vs. 0.16 ± 0.06 ng/ml, P < 0.05), IL-2 (20.29 ± 4.23 vs. 13.09 ± 3.13 ng/ml, P < 0.05), and IL-6 (0.19 ± 0.03 vs. 0.12 ± 0.05 ng/ml, P < 0.05) levels, and a significant decrease of ACTH (16.95 ± 5.46 vs. 22.96 ± 7.32 pg/ml, P = 0.03). Immunohistochemical staining showed the decreased number of pituitary ACTH-positive cells in both Groups B and C (P < 0.05) as compared to Group A. These results have lead us to believe that acute psychological stress can activate the pituitary-adrenal axis and lead to elevation of serum IL-2, IL-6 concentrations. Combined with high-intensity exercise, it can result in the increase of serum CORT, IL-1β, IL-2, IL-6 levels, and the suppression of ACTH.

  9. Water-quality assessment of runoff from a rural highway bridge near Tallahassee, Florida

    USGS Publications Warehouse

    Irwin, G.A.; Losey, Gerald T.

    1978-01-01

    Runoff from a rural highway bridge on U.S. 27 near Tallahassee, Florida, was found to have an insignificant water-quality loading impact on the Ochlockonee River. Potential annual-runoff loads on the bridge surface for virtually all constituents studied were less than one percent of those transported by the river at the study site. The loading rates for some parameters were significantly related to traffic counts, but the regression equations were limited to traffic ranges between 3,800 to 4,200 vehicles per day in 1977-78. Precipitation samples indicated that a significant percentage of the constituent loading to the bridge surface is from atmospheric deposition. (Woodard-USGS)

  10. On floats and float tests

    NASA Technical Reports Server (NTRS)

    Seewald, Friedrich

    1931-01-01

    The principal source of information on float resistance is the model test. In view of the insuperable difficulties opposing any attempt at theoretical treatment of the resistance problem, particularly at attitudes which tend toward satisfactory take-off, such as the transitory stage to planing, the towing test is and will remain the primary method for some time.

  11. Sensor and Video Monitoring of Water Quality at Bristol Floating Harbour

    NASA Astrophysics Data System (ADS)

    Chen, Yiheng; Han, Dawei

    2017-04-01

    Water system is an essential component in a smart city for its sustainability and resilience. The harbourside is a focal area of​ ​Bristol with new buildings and features redeveloped in the last ten years, attracting numerous visitors by the diversity of attractions and beautiful views. There is a strong​ ​relationship between the satisfactory of the visitors and local people with the water quality in the Harbour. The freshness and beauty of the water body would please people as well as benefit the aquatic ecosystems. As we are entering a data-rich era, this pilot project aims to explore the concept of using​ ​ video cameras and smart sensors to collect and monitor water quality condition at the Bristol harbourside. The video cameras and smart sensors are connected to the Bristol Is Open network, an open programmable city platform. This will be the​ first​ attempt to collect water quality data in real time in the​ ​Bristol urban area with the wireless network. The videos and images of the water body collected by the cameras will be correlated with the in-situ water quality parameters for research​ ​purposes. The successful implementation of the sensors can attract more academic researchers and industrial partners to expand the sensor network to multiple locations​ ​around the city covering the other parts of the Harbour and River Avon, leading to a new generation of urban system infrastructure model.

  12. Buoyant force and sinking conditions of a hydrophobic thin rod floating on water

    NASA Astrophysics Data System (ADS)

    Liu, Jian-Lin; Feng, Xi-Qiao; Wang, Gang-Feng

    2007-12-01

    Owing to the superhydrophobicity of their legs, such creatures as water striders and fisher spiders can stand effortlessly, walk and jump quickly on water. Directed toward understanding their superior repellency ability, we consider hydrophobic thin rods of several representative cross sections pressing a water surface. First, the shape function of the meniscus surrounding a circular rod is solved analytically, and thereby the maximal buoyant force is derived as a function of the Young’s contact angle and the rod radius. Then we discuss the critical conditions for a rod to sink into water, including the maximal volume condition and the meniscus-contact condition. Furthermore, we study the sinking conditions and the maximal buoyant forces of hydrophobic long rods with elliptical, triangular, or hexagonal cross-section shapes. The theoretical solutions are quantitatively consistent with existing experimental and numerical results. Finally, the optimized structures of water strider legs are analyzed to elucidate why they can achieve a very big buoyant force on water.

  13. Development of ultrasound-assisted emulsification microextraction based on solidification of a floating organic droplet for determination of organochlorine pesticides in water samples.

    PubMed

    Shu, Bin; Yang, Zhaoguang; Lee, Hsiaowan; Qiu, Bo; Li, Haipu

    2016-02-01

    An ultrasound-assisted emulsification microextraction based on the solidification of a floating organic droplet followed by gas chromatography with electron capture detection was developed for the simultaneous determination of 13 organochlorine pesticides in water samples. In the proposed method, ultrasound was applied to achieve the emulsification without addition of any dispersive solvent. In consequence, the volume of extraction phase remained unaffected by the ion strength of aqueous phase and high extraction recoveries were obtained. It was also found that dilution of the floating phase with acetone was necessary for preventing peak splitting in chromatogram. Under optimal conditions, the proposed method provided good sensitivity (the detection limits of organochlorine pesticides ranged from 1.3 to 3.9 ng/L) and good repeatability of extraction (below 6.5%, n = 5). The recoveries in reservoir and river water samples were between 75.8% and 96.9%.

  14. Benchmark calculations of excess electrons in water cluster cavities: balancing the addition of atom-centered diffuse functions versus floating diffuse functions.

    PubMed

    Zhang, Changzhe; Bu, Yuxiang

    2016-09-14

    Diffuse functions have been proved to be especially crucial for the accurate characterization of excess electrons which are usually bound weakly in intermolecular zones far away from the nuclei. To examine the effects of diffuse functions on the nature of the cavity-shaped excess electrons in water cluster surroundings, both the HOMO and LUMO distributions, vertical detachment energies (VDEs) and visible absorption spectra of two selected (H2O)24(-) isomers are investigated in the present work. Two main types of diffuse functions are considered in calculations including the Pople-style atom-centered diffuse functions and the ghost-atom-based floating diffuse functions. It is found that augmentation of atom-centered diffuse functions contributes to a better description of the HOMO (corresponding to the VDE convergence), in agreement with previous studies, but also leads to unreasonable diffuse characters of the LUMO with significant red-shifts in the visible spectra, which is against the conventional point of view that the more the diffuse functions, the better the results. The issue of designing extra floating functions for excess electrons has also been systematically discussed, which indicates that the floating diffuse functions are necessary not only for reducing the computational cost but also for improving both the HOMO and LUMO accuracy. Thus, the basis sets with a combination of partial atom-centered diffuse functions and floating diffuse functions are recommended for a reliable description of the weakly bound electrons. This work presents an efficient way for characterizing the electronic properties of weakly bound electrons accurately by balancing the addition of atom-centered diffuse functions and floating diffuse functions and also by balancing the computational cost and accuracy of the calculated results, and thus is very useful in the relevant calculations of various solvated electron systems and weakly bound anionic systems.

  15. Floating orbital molecular dynamics simulations.

    PubMed

    Perlt, Eva; Brüssel, Marc; Kirchner, Barbara

    2014-04-21

    We introduce an alternative ab initio molecular dynamics simulation as a unification of Hartree-Fock molecular dynamics and the floating orbital approach. The general scheme of the floating orbital molecular dynamics method is presented. Moreover, a simple but sophisticated guess for the orbital centers is provided to reduce the number of electronic structure optimization steps at each molecular dynamics step. The conservation of total energy and angular momentum is investigated in order to validate the floating orbital molecular dynamics approach with and without application of the initial guess. Finally, a water monomer and a water dimer are simulated, and the influence of the orbital floating on certain properties like the dipole moment is investigated.

  16. Air-water Gas Exchange Rates on a Large Impounded River Measured Using Floating Domes (Poster)

    EPA Science Inventory

    Mass balance models of dissolved gases in rivers typically serve as the basis for whole-system estimates of greenhouse gas emission rates. An important component of these models is the exchange of dissolved gases between air and water. Controls on gas exchange rates (K) have be...

  17. Air-water Gas Exchange Rates on a Large Impounded River Measured Using Floating Domes (Poster)

    EPA Science Inventory

    Mass balance models of dissolved gases in rivers typically serve as the basis for whole-system estimates of greenhouse gas emission rates. An important component of these models is the exchange of dissolved gases between air and water. Controls on gas exchange rates (K) have be...

  18. Phytofiltration of cadmium from water by Limnocharis flava (L.) Buchenau grown in free-floating culture system.

    PubMed

    Abhilash, P C; Pandey, Vimal Chandra; Srivastava, Pankaj; Rakesh, P S; Chandran, Smitha; Singh, Nandita; Thomas, A P

    2009-10-30

    A hydroponics experiment was conducted to examine the phytofiltration of Cd by Limnocharis flava (L.) Buchenau grown in low-level Cd-contaminated water. For this, 45 d old seedlings of L .flava were transferred to a floating-support culture system containing nutrient solution spiked with four levels of Cd (0.5, 1, 2 and 4 mg l(-1)) and were separately harvested after 3, 7, 21 and 30 d. After 30 d harvesting, the percentage removal of Cd from the above four treatments reached up to 98, 96, 95 and 93%, respectively. Interestingly, all treatments had higher growth rate than control at 95% confidence level and plants still remained healthy at 4 mg l(-1) Cd exposure. The bioaccumulation study showed a linear relationship of Cd (R(2)=0.896-0.999) in all plant parts with the exposure time (3-30 d) and Cd concentrations in hydroponics system (0.5-4 mg l(-1)). Although, the root of L. flava had higher Cd concentration than leaf and peduncles, the total Cd concentrations in aerial plant parts were higher than the roots. The maximum bioconcentration factor (BCF) and translocation factor (TF) value of L. flava were calculated as 984.42 and 1.43, respectively. Estimated Cd accumulation capacity of L. flava per unit area (m(2)) was found to be in the range of 218. 35-1698.92 mg m(-2).The experimental results demonstrated that L. flava is a suitable candidate for the phytofiltartion (>93%) of Cd from low-level Cd-contaminated water.

  19. Dispersive liquid-liquid microextraction based on solidification of floating organic droplet for the determination of triazine and triazoles in mineral water samples.

    PubMed

    Bolzan, Cátia M; Caldas, Sergiane S; Guimarães, Bruno S; Primel, Ednei G

    2016-09-01

    A simple, rapid, and sensitive method for the determination of atrazine, simazine, cyproconazole, tebuconazole, and epoxiconazole in mineral water employing the dispersive liquid-liquid microextraction with solidification of a floating organic drop with determination by liquid chromatography tandem mass spectrometry has been developed. A mixed solution of 250 μL 1-dodecanol and 1250 μL methanol was injected rapidly into 10 mL aqueous solution (pH 7.0) with 2% w/v NaCl. After centrifugation for 5 min at 2000 rpm, the organic solvent droplets floated on the surface of the aqueous solution and the floating solvent solidified. The method limits of detection were between 3.75 and 37.5 ng/L and limits of quantification were between 12.5 and 125 ng/L. The recoveries ranged from 70 to 118% for repeatability and between 76 and 95% for intermediate precision with a relative standard deviation from 2 to 18% for all compounds. Low matrix effect was observed. The proposed method can be successfully applied in routine analysis for determination of pesticide residues in mineral water samples, allowing for monitoring of triazine and triazoles at levels below the regulatory limits set by international and national legislations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. [Environmental Effects of Algae Bloom Cluster: Impact on the Floating Plant Water Hyacinth Photosynthesis].

    PubMed

    Bao, Xian-ming; Gu, Dong-xiang; Wu, Ting-ting; Shi, Zu-liang; Liu, Guo-feng; Han Shi-qun; Zhou, Shi-qun; Zhou, Qing

    2015-06-01

    It is an efficient and effective ecological restoration method by using the adaptability, large biomass of aquatic plants to purify the polluted water at present. However, there is a lack of systematic research on the impact on the physiological ecology of aquatic plants and its environmental effects of algae blooms cluster in summer. The aim of this paper is to reveal the mechanism of macrophytes demise in a shallow ecosystem by studying the influence on photosynthesis of water hyacinth caused by the cynaobacterial blooms gathered, and also to provide the theoretical basis for full effects of purification function of macrophytes to reduce the negative effects on the aquatic plants after algae blooms gathered during the higher temperature (not lower 25 degrees C) through simulating experiments. Results showed the dissolved oxygen quickly consumed in root zone of aquatic plants after algae blooms gathered and showed a lack of oxygen (DO < 0.2 mg x L(-1)); and the ORP was lower than -100 mV after 1 d, and it declined to -200 mV at the end of the experiment, and pH declined 0. 7unit compared with that of control group ( CK). There were lots of nutrients releasing to the water after the algae cell died and the NH4+ -N concentration was 102 times higher than that of the control group root zone. And the macrophytes photosynthesis reduced quickly and the plant body damaged with the intimidation of higher NH4+ -N concentration (average content was 45.6 mg x L(-1)) and hypoxia after algae cell decomposed. The average net photosynthesis rate, leaf transpiration rate were 0.6 times, 0.55 times of the control group, and they reduced to 3.96 micromol x (m2 x s)(-1), 1.38 mmol x (m2 x s)(-1), respectively. At the end of the experiment, they were 22.0 micromol x (m2 x s)(-1) and 7.61 mmol x (m2 x s)(-1) for the control group. Results also showed the algae bloom together had the irreversible damage to the aquatic plants. So in the practice of ecological restoration, it should

  1. Keto-enol tautomerization of a peptide group with proton transfer through a water bridge

    NASA Astrophysics Data System (ADS)

    Isaev, A. N.

    2015-08-01

    Calculations were performed for structures of the keto and enol forms of dipeptide N-glycylglycine and its complexes with water molecules using the quantum-chemical B3LYP/6-31+G** method. The barrier for the reactions of the dipeptide's keto-enol tautomerization that proceed by the mechanism of intramolecular proton transfer and proton transfer through water molecules connecting the oxygen and nitrogen atoms of the (-CONH-) peptide group was calculated. It was found that the barrier of the keto-enol tautomerization reaction with proton transfer by an exchange mechanism through water molecules is decreased halved compared to direct intramolecular transfer. It was shown that addition of a second water molecule in the transfer chain leads to linearization of the H-bonds bridges and increases hydrogen bonding between the peptide group and water molecules, but has virtually no influence on the calculated value of the keto-enol tautomerization barrier of about 20 kcal/mol. The structures of the transition states of the reaction indicate that the transfer of protons along the H-bonds chain is in both cases concerted but asynchronous. The order of the protons translocations along the water bridge is explained on the basis of NBO analysis of the relative strength of H-bonds in the transfer chain when the proton involved in the strongest H-bond is transferred first.

  2. Water-Bridge Mediates Recognition of mRNA Cap in eIF4E.

    PubMed

    Lama, Dilraj; Pradhan, Mohan R; Brown, Christopher J; Eapen, Rohan S; Joseph, Thomas L; Kwoh, Chee-Keong; Lane, David P; Verma, Chandra S

    2017-01-03

    Ligand binding pockets in proteins contain water molecules, which play important roles in modulating protein-ligand interactions. Available crystallographic data for the 5' mRNA cap-binding pocket of the translation initiation factor protein eIF4E shows several structurally conserved waters, which also persist in molecular dynamics simulations. These waters engage an intricate hydrogen-bond network between the cap and protein. Two crystallographic waters in the cleft of the pocket show a high degree of conservation and bridge two residues, which are part of an evolutionarily conserved scaffold. This appears to be a preformed recognition module for the cap with the two structural waters facilitating an efficient interaction. This is also recapitulated in a new crystal structure of the apo protein. These findings open new windows for the design and screening of compounds targeting eIF4E.

  3. Kinetics of Cr(III) and Cr(VI) removal from water by two floating macrophytes.

    PubMed

    Maine, M A; Hadad, H R; Sánchez, G; Caffaratti, S; Pedro, M C

    2016-01-01

    The aim of this work was to compare Cr(III) and Cr(VI) removal kinetics from water by Pistia stratiotes and Salvinia herzogii. The accumulation in plant tissues and the effects of both Cr forms on plant growth were also evaluated. Plants were exposed to 2 and 6 mg L(-1) of Cr(III) or Cr(VI) during 30 days. At the end of the experiment, Cr(VI) removal percentages were significantly lower than those obtained for Cr(III) for both macrophytes. Cr(III) removal kinetics involved a fast and a slow component. The fast component was primarily responsible for Cr(III) removal while Cr(VI) removal kinetics involved only a slow process. Cr accumulated principally in the roots. In the Cr(VI) treatments a higher translocation from roots to aerial parts than in Cr(III) treatments was observed. Both macrophytes demonstrated a high ability to remove Cr(III) but not Cr(VI). Cr(III) inhibited the growth at the highest studied concentration of both macrophytes while Cr(VI) caused senescence. These results have important implications in the use of constructed wetlands for secondary industrial wastewater treatment. Common primary treatments of effluents containing Cr(VI) consists in its reduction to Cr(III). Cr(III) concentrations in these effluents are normally below the highest studied concentrations in this work.

  4. 31. Floating original Ship Canal draw (in background) to University ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. Floating original Ship Canal draw (in background) to University Heights location. New Ship Canal draw in foreground. June 1906 photograph. - University Heights Bridge, Spanning Harlem River at 207th Street & West Harlem Road, New York County, NY

  5. CANVAS FINISH TO REMOVE FLOAT MARKS. View is to the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CANVAS FINISH TO REMOVE FLOAT MARKS. View is to the northwest of deck finishing operations - South Fork Trinity River Bridge, State Highway 299 spanning South Fork Trinity River, Salyer, Trinity County, CA

  6. 33 CFR 144.01-10 - Equipment for life floats.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Equipment for life floats. 144.01... for life floats. (a) Each lifefloat shall be provided with a painter. This painter shall be a manila... 1/2 inch in diameter. (b) Each life float must have a water light of an approved automatic...

  7. 33 CFR 144.01-10 - Equipment for life floats.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Equipment for life floats. 144.01... for life floats. (a) Each lifefloat shall be provided with a painter. This painter shall be a manila... 1/2 inch in diameter. (b) Each life float must have a water light of an approved automatic...

  8. 33 CFR 144.01-10 - Equipment for life floats.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Equipment for life floats. 144.01... for life floats. (a) Each lifefloat shall be provided with a painter. This painter shall be a manila... 1/2 inch in diameter. (b) Each life float must have a water light of an approved automatic...

  9. 33 CFR 144.01-10 - Equipment for life floats.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Equipment for life floats. 144.01... for life floats. (a) Each lifefloat shall be provided with a painter. This painter shall be a manila... 1/2 inch in diameter. (b) Each life float must have a water light of an approved automatic...

  10. ICE911 Research: Floating Safe Inert Materials to Preserve Ice and Conserve Water in Order to Mitigate Climate Change Impacts

    NASA Astrophysics Data System (ADS)

    Field, L. A.; Manzara, A.; Chetty, S.; Venkatesh, S.; Scholtz, A.

    2015-12-01

    bodies of water cooler using these floating materials could help avoid scenarios like the overheated lakes and streams that led to millions of fish killed this summer in Washington State. Third, Ice911's materials can later be removed if no longer needed, and could be repurposed to another area in need.

  11. Transference numbers of concentrated electrolytes and characterization of salt bridges in the ethanol + water solvent mixtures

    SciTech Connect

    Mussini, P.R.; Mussini, T.; Perelli, A.; Rondinini, S.

    1995-07-01

    Electromotive force measurements have been made using the transference cells: Ag{vert_bar}AgCl{vert_bar}MCl (m{sub 2}){vert_bar}MCl (m{sub 1}){vert_bar}AgCl{vert_bar}Ag and M(Hg){vert_bar}MCl (m{sub 1}){vert_bar}MCl (m{sub 2}){vert_bar}M(Hg) (where M = Na, K, and Cs and M(Hg) denotes a flowing M-amalgam electrode) at various molalities m{sub 2} > m{sub 1} of MCl salts in ethanol (1) + water (2) with ethanol mass fraction w{sub 1} up to 0.8. The results indicate that the ions in CsCl have approximately equal transference number from pure water up to w{sub 1} = 0.6 for ethanol, but at w{sub 1} = 0.7 the transference numbers of the ions start to differ. Also, the transference numbers of the ions in KCl in ethanol + water approach 0.5, but at w{sub 1} > 0.4, the KCl solubility becomes insufficient for a salt bridge function. NaCl, which is not good as a salt bridge in water, is more useful with increasing ethanol concentrations, and the transference numbers of the ions approach 0.5 at ethanol mass fraction w{sub 1} > 0.8.

  12. Flinking: Neither Floating nor Sinking.

    ERIC Educational Resources Information Center

    Wilson, Roger B.

    1993-01-01

    Describes an activity that challenges students to make an object that, when released under water, does not float up or sink down. The main concept this activity investigates is the density of ordinary objects in comparison to the density of water. (PR)

  13. Flinking: Neither Floating nor Sinking.

    ERIC Educational Resources Information Center

    Wilson, Roger B.

    1993-01-01

    Describes an activity that challenges students to make an object that, when released under water, does not float up or sink down. The main concept this activity investigates is the density of ordinary objects in comparison to the density of water. (PR)

  14. Distribution comparison and risk assessment of free-floating and particle-attached bacterial pathogens in urban recreational water: Implications for water quality management.

    PubMed

    Fang, Tingting; Cui, Qijia; Huang, Yong; Dong, Peiyan; Wang, Hui; Liu, Wen-Tso; Ye, Quanhui

    2017-09-14

    The risk of pathogen exposure in recreational water is a concern worldwide. Moreover, suspended particles, as ideal shelters for pathogens, in these waters also need attention. However, the risk caused by the pathogen-particle attachment is largely unknown. Accordingly, water samples in three recreational lakes in Beijing were collected and separated into free-floating (FL, 0.22-5μm) and particle-attached (PA, >5μm) fractions. Next-generation sequencing (NGS) was employed to determine the diversity of genera containing pathogens, and quantitative PCR (qPCR) was used to assess the presence of genes from Escherichia coli (uidA), Salmonella enterica (invA), Aeromonas spp. (aerA), Mycobacterium avium (16S) and Pseudomonas aeruginosa (oaa). The NGS results showed stable pathogen genera composition distinctions between the PA and FL fractions. Some genera, such as Aeromonas and Mycobacterium, exhibited higher abundances in the PA fractions. qPCR revealed that most of the gene concentrations were higher within particles than were FL fractions. Some gene levels showed correlations with the particle concentrations and lake nutrient levels. Further quantitative microbial risk assessment (QMRA) of selected strains (S. enterica and M. avium) indicated a higher health risk during secondary contact activities in lakes with more nutrients and particles. We concluded that suspended particles (mainly composed of algae) in urban recreational water might influence the pathogen distribution and could serve as reservoirs for pathogen contamination, with important management implications. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Floating Point Control Library

    SciTech Connect

    Lee, G. L.; Shereda, C.

    2007-08-02

    Floating Point Control is a Library that allows for the manipulation of floating point unit exception masking funtions control exceptions in both the Streaming "Single Instruction, Multiple Data" Extension 2 (SSE2) unit and the floating point unit simultaneously. FPC also provides macros to set floating point rounding and precision control.

  16. Influence of Organic Chemicals on Water Molecule Bridges in Soil Organic Matter of a Sapric Histosol.

    PubMed

    Ondruch, Pavel; Kučerík, Jiri; Steinmetz, Zacharias; Schaumann, Gabriele E

    2017-03-02

    Water molecules in soil organic matter (SOM) can form clusters bridging neighboring molecular segments (water molecule bridges; WaMB). WaMB are hypothesized to enhance physical entrapment of organic chemicals and to control the rigidity of the SOM supramolecular structure. However, the understanding of WaMB dynamics in SOM is still limited. We investigated the relation between WaMB stability and the physicochemical properties of their environment by treating a sapric histosol with various solvents and organic chemicals. Based on predictions from molecular modeling, we hypothesized that the stability of WaMB, measured by differential scanning calorimetry, increases with decreasing ability of a chemical to interact with water molecules of the WaMB. The interaction ability between WaMB and the chemicals was characterized by linear solvation energy relationships. WaMB stability in solvent-treated samples was found to decrease with increasing ability of a solvent to undergo H-donor/acceptor interactions. Spiking with an organic chemical stabilized (naphthalene) or destabilized (phenol) the WaMB. WaMB stability and matrix rigidity were generally reduced strongly and fast when hydrophilic chemicals entered the soil. The physicochemical aging following this destabilization is slow, but leads to a successive WaMB stabilization and matrix stiffening.

  17. Bridging Hydroxyls on Anatase TiO2(101) by Water Dissociation in Oxygen Vacancies.

    PubMed

    Nadeem, Immad M; Harrison, George T; Wilson, Axel; Pang, Chi L; Zegenhagen, Jörg; Thornton, Geoff

    2017-10-09

    Titanium dioxide is a promising candidate for photocatalytic H2 fuel production, and understanding water splitting on TiO2 surfaces is vital toward explaining and improving the generation of H2. In this work, we electron irradiate anatase TiO2(101) at room temperature to create metastable surface oxygen vacancies in order to investigate their ability to dissociate H2O. Our scanning tunneling microscopy investigations suggest that the surface oxygen vacancies can dissociate H2O by forming bridging OH species. This claim is supported by theoretical calculations from the literature and our previously published spectroscopic measurements.

  18. Bridging the Gap: The 'Soft Path' for Improving Resilience and Adaptability of Water Systems (Invited)

    NASA Astrophysics Data System (ADS)

    Gleick, P. H.

    2010-12-01

    The failure of traditional water management systems in the 20th century -- what I call the "hard path for water" -- is evident in several ways, including the persistent inability to meet basic human needs for safe water and adequate sanitation for vast populations, ongoing and accelerating aquatic ecosystem collapses , and growing political disputes over water allocation, management, and use, even in regions where substantial investment in water has been made. Progress in resolving these problems, especially in the face of unavoidable climate changes, growing populations, and constrained financial systems, will require bridging hydrologic and social sciences in new ways. Integrating social and cultural knowledge with new economic and technological tools and classical hydrologic and climatological sciences can produce a new “soft path for water” that offers the opportunity to move toward sustainable water systems. This talk will define the soft path for water and offer examples of innovative steps already being taken along that path in the western United States, South Africa, India, and elsewhere.

  19. Analysis of Satellite and Airborne Imagery for Detection of Water Hyacinth and Other Invasive Floating Macrophytes and Tracking of Aquatic Weed Control Efficacy

    NASA Technical Reports Server (NTRS)

    Potter, Christopher

    2016-01-01

    Waterways of the Sacramento San Joaquin Delta have recently become infested with invasive aquatic weeds such as floating water hyacinth (Eichhoria crassipes) and water primrose (Ludwigia peploides). These invasive plants cause many negative impacts, including, but not limited to: the blocking of waterways for commercial shipping and boating; clogging of irrigation screens, pumps and canals; and degradation of biological habitat through shading. Zhang et al. (1997, Ecological Applications, 7(3), 1039-1053) used NASA Landsat satellite imagery together with field calibration measurements to map physical and biological processes within marshlands of the San Francisco Bay. Live green biomass (LGB) and related variables were correlated with a simple vegetation index ratio of red and near infra-red bands from Landsat images. More recently, the percent (water area) cover of water hyacinth plotted against estimated LGB of emergent aquatic vegetation in the Delta from September 2014 Landsat imagery showed an 80 percent overall accuracy. For the past two years, we have partnered with the U. S. Department of Agriculture (USDA) and the Department of Plant Sciences, University of California at Davis to conduct new validation surveys of water hyacinth and water primrose coverage and LGB in Delta waterways. A plan is underway to transfer decision support tools developed at NASA's Ames Research Center based on Landsat satellite images to improve Delta-wide integrated management of floating aquatic weeds, while reducing chemical control costs. The main end-user for this application project will be the Division of Boating and Waterways (DBW) of the California Department of Parks and Recreation, who has the responsibility for chemical control of water hyacinth in the Delta.

  20. A Comparison of Platform Options for Deep-water Floating Offshore Vertical Axis Wind Turbines: An Initial Study.

    SciTech Connect

    Bull, Diana L; Fowler, Matthew; Goupee, Andrew

    2014-08-01

    This analysis utilizes a 5 - MW VAWT topside design envelope created by Sandia National Laborator ies to compare floating platform options fo r each turbine in the design space. The platform designs are based on two existing designs, the OC3 Hywind spar - buoy and Principal Power's WindFloat semi - submersible. These designs are scaled using Froude - scaling relationships to determine an appropriately sized spar - buoy and semi - submersible design for each topside. Both the physical size of the required platform as well as mooring configurations are considered. Results are compared with a comparable 5 - MW HAWT in order to identify potential differences in the platform and mooring sizing between the VAWT and HAWT . The study shows that there is potential for cost savings due to reduced platform size requirements for the VAWT.

  1. Phenolic content of daylight-exposed and shaded floating leaves of water lilies (Nymphaeaceae) in relation to infection by fungi.

    PubMed

    Vergeer, L H T; van der Velde, G

    1997-11-01

    Under suboptimal growing conditions (e.g. a lack of sunshine), floating leaves of Nymphaea alba and Nuphar lutea can become heavily infected with the fungi Colletotrichum nymphaeae and Pythium F, respectively. These fungi normally act as decomposers of senescent leaves. Mature leaves of Nymphaea alba and Nuphar lutea contain high concentrations of phenolics, secondary substances known for their fungistatic properties. The production of these compounds requires energy and primary metabolites. The hypothesis that suboptimal growing conditions reduce the ability of nymphaeids to maintain a sufficiently high level of phenolics, thereby making them more vulnerable to infection by fungi, was tested. Outdoor mesocosm experiments were used to examine the response of floating leaves of Nymphaea alba and Nuphar lutea to reduced light availability. Shading significantly reduced the phenolic content of the leaves. This was accompanied by higher disease severity. The outcome of this experiment is also discussed in relation to the higher nitrogen content measured in shaded leaves.

  2. Characterization of water-quality and bed-sediment conditions in Currituck Sound, North Carolina, prior to the Mid-Currituck Bridge construction, 2011–15

    USGS Publications Warehouse

    Wagner, Chad R.; Fitzgerald, Sharon; Antolino, Dominick J.

    2015-12-24

    The characterization of water-quality and bed-sediment chemistry in Currituck Sound along the proposed alignment of the Mid-Currituck Bridge summarized herein provides a baseline for determining the effect of bridge construction and bridge deck runoff on environmental conditions in Currituck Sound.

  3. Topoisomerase IV-quinolone interactions are mediated through a water-metal ion bridge: mechanistic basis of quinolone resistance.

    PubMed

    Aldred, Katie J; McPherson, Sylvia A; Turnbough, Charles L; Kerns, Robert J; Osheroff, Neil

    2013-04-01

    Although quinolones are the most commonly prescribed antibacterials, their use is threatened by an increasing prevalence of resistance. The most common causes of quinolone resistance are mutations of a specific serine or acidic residue in the A subunit of gyrase or topoisomerase IV. These amino acids are proposed to serve as a critical enzyme-quinolone interaction site by anchoring a water-metal ion bridge that coordinates drug binding. To probe the role of the proposed water-metal ion bridge, we characterized wild-type, GrlA(E85K), GrlA(S81F/E85K), GrlA(E85A), GrlA(S81F/E85A) and GrlA(S81F) Bacillus anthracis topoisomerase IV, their sensitivity to quinolones and related drugs and their use of metal ions. Mutations increased the Mg(2+) concentration required to produce maximal quinolone-induced DNA cleavage and restricted the divalent metal ions that could support quinolone activity. Individual mutation of Ser81 or Glu85 partially disrupted bridge function, whereas simultaneous mutation of both residues abrogated protein-quinolone interactions. Results provide functional evidence for the existence of the water-metal ion bridge, confirm that the serine and glutamic acid residues anchor the bridge, demonstrate that the bridge is the primary conduit for interactions between clinically relevant quinolones and topoisomerase IV and provide a likely mechanism for the most common causes of quinolone resistance.

  4. Topoisomerase IV-quinolone interactions are mediated through a water-metal ion bridge: mechanistic basis of quinolone resistance

    PubMed Central

    Aldred, Katie J.; McPherson, Sylvia A.; Turnbough, Charles L.; Kerns, Robert J.; Osheroff, Neil

    2013-01-01

    Although quinolones are the most commonly prescribed antibacterials, their use is threatened by an increasing prevalence of resistance. The most common causes of quinolone resistance are mutations of a specific serine or acidic residue in the A subunit of gyrase or topoisomerase IV. These amino acids are proposed to serve as a critical enzyme-quinolone interaction site by anchoring a water-metal ion bridge that coordinates drug binding. To probe the role of the proposed water-metal ion bridge, we characterized wild-type, GrlAE85K, GrlAS81F/E85K, GrlAE85A, GrlAS81F/E85A and GrlAS81F Bacillus anthracis topoisomerase IV, their sensitivity to quinolones and related drugs and their use of metal ions. Mutations increased the Mg2+ concentration required to produce maximal quinolone-induced DNA cleavage and restricted the divalent metal ions that could support quinolone activity. Individual mutation of Ser81 or Glu85 partially disrupted bridge function, whereas simultaneous mutation of both residues abrogated protein–quinolone interactions. Results provide functional evidence for the existence of the water-metal ion bridge, confirm that the serine and glutamic acid residues anchor the bridge, demonstrate that the bridge is the primary conduit for interactions between clinically relevant quinolones and topoisomerase IV and provide a likely mechanism for the most common causes of quinolone resistance. PMID:23460203

  5. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Floating OCS facilities. 143.120...) OUTER CONTINENTAL SHELF ACTIVITIES DESIGN AND EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner or operator of the...

  6. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Floating OCS facilities. 143.120...) OUTER CONTINENTAL SHELF ACTIVITIES DESIGN AND EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner or operator of the...

  7. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Floating OCS facilities. 143.120...) OUTER CONTINENTAL SHELF ACTIVITIES DESIGN AND EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner or operator of the...

  8. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Floating OCS facilities. 143.120...) OUTER CONTINENTAL SHELF ACTIVITIES DESIGN AND EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner or operator of the...

  9. 33 CFR 144.01-15 - Alternates for life floats.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Alternates for life floats. 144... for life floats. (a) Approved lifeboats, approved life rafts or approved inflatable life rafts may be used in lieu of approved life floats for either all or part of the capacity required. When...

  10. 33 CFR 144.01-15 - Alternates for life floats.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Alternates for life floats. 144... for life floats. (a) Approved lifeboats, approved life rafts or approved inflatable life rafts may be used in lieu of approved life floats for either all or part of the capacity required. When...

  11. 33 CFR 144.01-15 - Alternates for life floats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Alternates for life floats. 144... for life floats. (a) Approved lifeboats, approved life rafts or approved inflatable life rafts may be used in lieu of approved life floats for either all or part of the capacity required. When...

  12. 33 CFR 144.01-15 - Alternates for life floats.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Alternates for life floats. 144... for life floats. (a) Approved lifeboats, approved life rafts or approved inflatable life rafts may be used in lieu of approved life floats for either all or part of the capacity required. When...

  13. 33 CFR 144.01-15 - Alternates for life floats.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Alternates for life floats. 144... for life floats. (a) Approved lifeboats, approved life rafts or approved inflatable life rafts may be used in lieu of approved life floats for either all or part of the capacity required. When...

  14. 10. LOOKING DOWN ON TUG AND CAR FLOAT BEING UNLOADED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. LOOKING DOWN ON TUG AND CAR FLOAT BEING UNLOADED AT BRIDGE NO. 11 SHOWING TRACK, LOCKING MECHANISMS, AND MOORING WINCH IN FOREGROUND. LOOKING EAST. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

  15. Role of the water-metal ion bridge in mediating interactions between quinolones and Escherichia coli topoisomerase IV.

    PubMed

    Aldred, Katie J; Breland, Erin J; Vlčková, Vladislava; Strub, Marie-Paule; Neuman, Keir C; Kerns, Robert J; Osheroff, Neil

    2014-09-02

    Although quinolones have been in clinical use for decades, the mechanism underlying drug activity and resistance has remained elusive. However, recent studies indicate that clinically relevant quinolones interact with Bacillus anthracis (Gram-positive) topoisomerase IV through a critical water-metal ion bridge and that the most common quinolone resistance mutations decrease drug activity by disrupting this bridge. As a first step toward determining whether the water-metal ion bridge is a general mechanism of quinolone-topoisomerase interaction, we characterized drug interactions with wild-type Escherichia coli (Gram-negative) topoisomerase IV and a series of ParC enzymes with mutations (S80L, S80I, S80F, and E84K) in the predicted bridge-anchoring residues. Results strongly suggest that the water-metal ion bridge is essential for quinolone activity against E. coli topoisomerase IV. Although the bridge represents a common and critical mechanism that underlies broad-spectrum quinolone function, it appears to play different roles in B. anthracis and E. coli topoisomerase IV. The water-metal ion bridge is the most important binding contact of clinically relevant quinolones with the Gram-positive enzyme. However, it primarily acts to properly align clinically relevant quinolones with E. coli topoisomerase IV. Finally, even though ciprofloxacin is unable to increase levels of DNA cleavage mediated by several of the Ser80 and Glu84 mutant E. coli enzymes, the drug still retains the ability to inhibit the overall catalytic activity of these topoisomerase IV proteins. Inhibition parallels drug binding, suggesting that the presence of the drug in the active site is sufficient to diminish DNA relaxation rates.

  16. Floating on oil.

    PubMed

    Zhang, Jihua; Deng, Xu; Butt, Hans-Jürgen; Vollmer, Doris

    2014-09-09

    We demonstrate that disk-shaped steel meshes coated with a superamphiphobic layer are able to float on water and on organic liquids. A coated disk-shaped steel mesh of 1 cm radius has a loading capacity of 17 mN in water and still remarkable 9 mN in n-hexadecane. Experimentally measured supporting forces and loading capacities agree well with theoretical predictions. Inspired by the giant water lily, pan-shaped "oil lilies" with even higher loading capacity and artificial oil striders carrying more than 10 times their own weight are designed. Even after the artificial devices are fully immersed into different liquids, they show self-draining properties due to capillary forces.

  17. Spans and suspensions: building bridges and water security through integrated water resource management.

    PubMed

    Catley-Carlson, Margaret

    2002-01-01

    There are three chasms that block the route to water security: the impact of population growth (and the associated urbanization); widespread malnutrition and poverty; conflict between agricultural demand and other human uses of water. To cross these chasms requires firstly education (primary education for girls is crucial) and the introduction of integrated water resource management. It requires the application of community energies and dedication, and the harnessing of private sector energies resources, but it will also need the development of innovative financial mechanisms. Above all it requires a major shift in the way we manage water, discarding prejudices and preconceptions, to address our water needs with imagination and commitment.

  18. Competition between Free-Floating Plants Is Strongly Driven by Previously Experienced Phosphorus Concentrations in the Water Column.

    PubMed

    Peeters, Edwin T H M; Neefjes, Rozemarijn E M; Zuidam, Bastiaan G van

    2016-01-01

    Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natans)and the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously experienced phosphorus

  19. Competition between Free-Floating Plants Is Strongly Driven by Previously Experienced Phosphorus Concentrations in the Water Column

    PubMed Central

    Peeters, Edwin T. H. M.; Neefjes, Rozemarijn E. M.; van Zuidam, Bastiaan G.

    2016-01-01

    Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natans)and the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously experienced phosphorus

  20. Dispersive liquid-liquid microextraction method based on solidification of floating organic drop for extraction of organochlorine pesticides in water samples.

    PubMed

    Leong, Mei-I; Huang, Shang-Da

    2009-11-06

    A new simple and rapid dispersive liquid-liquid microextraction method has been developed for the extraction and analysis of organochlorine pesticides (OCPs) in water samples. The method is based on the solidification of a floating organic drop (DLLME-SFO) and is combined with gas chromatography/electron capture detection (GC/ECD). Very little solvent is required in this method. The disperser solvent (200microL acetonitrile) containing 10microL hexadecane (HEX) is rapidly injected by a syringe into the 5.0mL water sample. After centrifugation, the fine HEX droplets (6+/-0.5microL) float at the top of the screw-cap test tube. The test tube is then cooled in an ice bath. After 5min, the HEX solvent solidifies and is then transferred into a conical vial, where it melts quickly at room temperature, and 1microL of it is injected into a gas chromatograph for analysis. Under optimum conditions, the enrichment factors and extraction recoveries are high and range between 37-872 and 82.9-102.5%, respectively. The linear range is wide (0.025-20microgL(-1)), and the limits of detection are between 0.011 and 0.11microgL(-1) for most of the analytes. The relative standard deviation (RSD) for 1microgL(-1) of OCPs in water was in the range of 5.8-8.8%. The performance of the method was gauged by analyzing samples of lake and tap water.

  1. "Floating shoulder" injuries.

    PubMed

    Heng, Kenneth

    2016-12-01

    "Floating shoulder" is a rare injury complex resulting from high-energy blunt force trauma to the shoulder, resulting in scapulothoracic dissociation. It is commonly associated with catastrophic neurovascular injury. Two cases of motorcyclists with floating shoulder injuries are described.

  2. An improved understanding of the natural resonances of moonpools contained within floating rigid-bodies: Theory and application to oscillating water column devices

    DOE PAGES

    Bull, Diana L.

    2015-09-23

    The fundamental interactions between waves, a floating rigid-body, and a moonpool that is selectively open to atmosphere or enclosed to purposefully induce pressure fluctuations are investigated. The moonpool hydrodynamic characteristics and the hydrodynamic coupling to the rigid-body are derived implicitly through reciprocity relations on an array of field points. By modeling the free surface of the moonpool in this manner, an explicit hydrodynamic coupling term is included in the equations of motion. This coupling results in the migration of the moonpool's natural resonance frequency from the piston frequency to a new frequency when enclosed in a floating rigid-body. Two geometriesmore » that highlight distinct aspects of marine vessels and oscillating water column (OWC) renewable energy devices are analyzed to reveal the coupled natural resonance migration. The power performance of these two OWCs in regular waves is also investigated. The air chamber is enclosed and a three-dimensional, linear, frequency domain performance model that links the rigid-body to the moonpool through a linear resistive control strategy is detailed. Furthermore, an analytic expression for the optimal linear resistive control values in regular waves is presented.« less

  3. An improved understanding of the natural resonances of moonpools contained within floating rigid-bodies: Theory and application to oscillating water column devices

    SciTech Connect

    Bull, Diana L.

    2015-09-23

    The fundamental interactions between waves, a floating rigid-body, and a moonpool that is selectively open to atmosphere or enclosed to purposefully induce pressure fluctuations are investigated. The moonpool hydrodynamic characteristics and the hydrodynamic coupling to the rigid-body are derived implicitly through reciprocity relations on an array of field points. By modeling the free surface of the moonpool in this manner, an explicit hydrodynamic coupling term is included in the equations of motion. This coupling results in the migration of the moonpool's natural resonance frequency from the piston frequency to a new frequency when enclosed in a floating rigid-body. Two geometries that highlight distinct aspects of marine vessels and oscillating water column (OWC) renewable energy devices are analyzed to reveal the coupled natural resonance migration. The power performance of these two OWCs in regular waves is also investigated. The air chamber is enclosed and a three-dimensional, linear, frequency domain performance model that links the rigid-body to the moonpool through a linear resistive control strategy is detailed. Furthermore, an analytic expression for the optimal linear resistive control values in regular waves is presented.

  4. Vertical temperature dynamics in the Northern Baltic Sea based on 3D modelling and data from shallow-water Argo floats

    NASA Astrophysics Data System (ADS)

    Westerlund, Antti; Tuomi, Laura

    2016-06-01

    3D hydrodynamic models often produce errors in the depth of the mixed layer and the vertical density structure. We used the 3D hydrodynamic model NEMO to investigate the effect of vertical turbulence parameterisations on seasonal temperature dynamics in the Bothnian Sea, Baltic Sea for the years 2012 and 2013. We used vertical profiles from new shallow-water Argo floats, operational in the area since 2012, to validate our model. We found that NEMO was able to reproduce the general features of the seasonal temperature variations in the study area, when meteorological forcing was accurate. The k-ε and k-ω schemes were selected for a more detailed analysis. Both schemes showed clear differences, but neither proved superior. While sea surface temperature was better simulated with the k-ω scheme, thermocline depth was clearly better with the k-ε scheme. We investigated the effect of wave-breaking on the mixing of the surface layer. The Craig and Banner parameterisation clearly improved the representation of thermocline depth. However, further tuning of the mixing parameterisations for the Baltic Sea is needed to better simulate the vertical temperature structure. We found the autonomous Baltic Sea Argo floats valuable for model validation and performance evaluation.

  5. Floating: sink or swim.

    PubMed

    Pronger, L

    1995-12-01

    Budget restrictions, fewer human resources and fluctuating patient populations have combined to increase the practice of floating general duty nurses. Floating occurs when a nurse from an overstaffed unit, based on patient load, is required to work in another unit that is understaffed. Floating is not a new practice, but it has always been an emotionally charged issue. Today, with more float pool nurses seeking the security of a permanent position in a home unit, the issue has increased in intensity.

  6. The Design of Floats

    NASA Technical Reports Server (NTRS)

    Sottorf, W

    1938-01-01

    Following a summary of the multiplicity of domestic and foreign floats and a brief enumeration of the requirements of floats, the essential form parameters and their effect on the qualities of floats are detailed. On this basis a standard float design is developed which in model families with varying length/beam ratio and angle of dead rise is analyzed by an experimental method which permits its best utilization on any airplane.

  7. WATER QUALITY ISSUES AND EXPECTATIONS REGARDING RECONSTRUCTION OF THE HIX BRIDGE, WESTPORT, MA

    EPA Science Inventory

    At present there is a large deposit of rocks beneath and near the Hix Bridge located on the East Branch of the Westport River system. Following the 1938 hurricane, remnants of a 19th century bridge were apparently deposited into this constriction. The existing bridge, built in 19...

  8. WATER QUALITY ISSUES AND EXPECTATIONS REGARDING RECONSTRUCTION OF THE HIX BRIDGE, WESTPORT, MA

    EPA Science Inventory

    At present there is a large deposit of rocks beneath and near the Hix Bridge located on the East Branch of the Westport River system. Following the 1938 hurricane, remnants of a 19th century bridge were apparently deposited into this constriction. The existing bridge, built in 19...

  9. Water2Invest: Global facility for calculating investments needed to bridge the climate-induced water gap

    NASA Astrophysics Data System (ADS)

    Straatsma, Menno; Droogers, Peter; Brandsma, Jairus; Buytaert, Wouter; Karssenberg, Derek; Meijer, Karen; van Aalst, Maaike; van Beek, Rens; Wada, Yoshihide; Bierkens, Marc

    2013-04-01

    Decision makers responsible for climate change adaptation investments are confronted with large uncertainties regarding future water availability and water demand, as well as the investment cost required to reduce the water gap. Moreover, scientists have worked hard to increase fundamental knowledge on climate change and its impacts (climate services), while practical use of this knowledge is limited due to a lack of tools for decision support under uncertain long term future scenarios (decision services). The Water2Invest project aims are to (i) assess the joint impact of climate change and socioeconomic change on water scarcity, (ii) integrate impact and potential adaptation in one flow, (iii) prioritize adaptation options to counteract water scarcity on their financial, regional socio-economic and environmental implications, and (iv) deliver all this information in an integrated user-friendly web-based service. Global water availability is computed between 2006 and 2100 using the PCR-GLOBWB water resources model at a 6 minute spatial resolution. Climate change scenarios are based on the fifth Assessment Report (AR5) of the IPCC Coupled Model Intercomparison Project (CMIP5) that defines four CO2 emission scenarios as representative concentration pathways. Water demand is computed for agriculture, industry, domestic, and environmental requirements based on socio-economic scenarios of increase in population and gross domestic product. Using a linear programming algorithm, water is allocated on a monthly basis over the four sectors. Based on these assessments, the user can evaluate various technological and infrastructural adaptation measures to assess the investments needed to bridge the future water gap. Regional environmental and socioeconomic effects of these investments are evaluated, such as environmental flows or downstream effects. A scheme is developed to evaluate the strategies on robustness and flexibility under climate change and scenario uncertainty

  10. Water-quality data for the Rio Grande between Picacho Bridge near Las Cruces and Calle del Norte Bridge near Mesilla, New Mexico, 1996-97

    USGS Publications Warehouse

    Huff, G.F.

    1998-01-01

    The City of Las Cruces is concerned about water quality in a reach of the Rio Grande that receives outfall from the City of Las Cruces wastewater-treatment plant. Water-quality samples were collected from the Rio Grande at Picacho Bridge near Las Cruces, New Mexico; from the sampling site at the City of Las Cruces wastewater-treatment plant; and from the Rio Grande at Calle del Norte Bridge near Mesilla, New Mexico. The samples were collected on 12 days from August 6, 1996, to February 28, 1997, and were analyzed for a suite of dissolved and total constituents including trace metals. Instantaneous stream discharge was measured concurrently with collection of the Rio Grande samples. At the wastewater- treatment plant, the City of Las Cruces provided instantaneous discharge rates concurrent with sampling. Quality-control measures used in this study to ensure analytical accuracy included replicate sampling, replicate analysis of split samples, ambient blanks, equipment blanks, and analysis of standard reference water samples.

  11. Urban water metabolism indicators derived from a water mass balance - Bridging the gap between visions and performance assessment of urban water resource management.

    PubMed

    Renouf, M A; Serrao-Neumann, S; Kenway, S J; Morgan, E A; Low Choy, D

    2017-10-01

    Improving resource management in urban areas has been enshrined in visions for achieving sustainable urban areas, but to date it has been difficult to quantify performance indicators to help identify more sustainable outcomes, especially for water resources. In this work, we advance quantitative indicators for what we refer to as the 'metabolic' features of urban water management: those related to resource efficiency (for water and also water-related energy and nutrients), supply internalisation, urban hydrological performance, sustainable extraction, and recognition of the diverse functions of water. We derived indicators in consultation with stakeholders to bridge this gap between visions and performance indicators. This was done by first reviewing and categorising water-related resource management objectives for city-regions, and then deriving indicators that can gauge performance against them. The ability for these indicators to be quantified using data from an urban water mass balance was also examined. Indicators of water efficiency, supply internalisation, and hydrological performance (relative to a reference case) can be generated using existing urban water mass balance methods. In the future, indicators for water-related energy and nutrient efficiencies could be generated by overlaying the urban water balance with energy and nutrient data. Indicators of sustainable extraction and recognising diverse functions of water will require methods for defining sustainable extraction rates and a water functionality index. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Application of the Multi-Dimensional Surface Water Modeling System at Bridge 339, Copper River Highway, Alaska

    USGS Publications Warehouse

    Brabets, Timothy P.; Conaway, Jeffrey S.

    2009-01-01

    The Copper River Basin, the sixth largest watershed in Alaska, drains an area of 24,200 square miles. This large, glacier-fed river flows across a wide alluvial fan before it enters the Gulf of Alaska. Bridges along the Copper River Highway, which traverses the alluvial fan, have been impacted by channel migration. Due to a major channel change in 2001, Bridge 339 at Mile 36 of the highway has undergone excessive scour, resulting in damage to its abutments and approaches. During the snow- and ice-melt runoff season, which typically extends from mid-May to September, the design discharge for the bridge often is exceeded. The approach channel shifts continuously, and during our study it has shifted back and forth from the left bank to a course along the right bank nearly parallel to the road. Maintenance at Bridge 339 has been costly and will continue to be so if no action is taken. Possible solutions to the scour and erosion problem include (1) constructing a guide bank to redirect flow, (2) dredging approximately 1,000 feet of channel above the bridge to align flow perpendicular to the bridge, and (3) extending the bridge. The USGS Multi-Dimensional Surface Water Modeling System (MD_SWMS) was used to assess these possible solutions. The major limitation of modeling these scenarios was the inability to predict ongoing channel migration. We used a hybrid dataset of surveyed and synthetic bathymetry in the approach channel, which provided the best approximation of this dynamic system. Under existing conditions and at the highest measured discharge and stage of 32,500 ft3/s and 51.08 ft, respectively, the velocities and shear stresses simulated by MD_SWMS indicate scour and erosion will continue. Construction of a 250-foot-long guide bank would not improve conditions because it is not long enough. Dredging a channel upstream of Bridge 339 would help align the flow perpendicular to Bridge 339, but because of the mobility of the channel bed, the dredged channel would

  13. Floating Boats

    ERIC Educational Resources Information Center

    Waugh, Michael

    2007-01-01

    The purpose of this article is to describe a simple laboratory activity in which students collect a series of measurements and then use graphical analysis to determine the nature of the relationship between an object's mass and the volume of water it displaces. In this activity, students explore the relationships between the mass of a floating…

  14. Floating Boats

    ERIC Educational Resources Information Center

    Waugh, Michael

    2007-01-01

    The purpose of this article is to describe a simple laboratory activity in which students collect a series of measurements and then use graphical analysis to determine the nature of the relationship between an object's mass and the volume of water it displaces. In this activity, students explore the relationships between the mass of a floating…

  15. Floating assembly of diatom Coscinodiscus sp. microshells.

    PubMed

    Wang, Yu; Pan, Junfeng; Cai, Jun; Zhang, Deyuan

    2012-03-30

    Diatoms have silica frustules with transparent and delicate micro/nano scale structures, two dimensional pore arrays, and large surface areas. Although, the diatom cells of Coscinodiscus sp. live underwater, we found that their valves can float on water and assemble together. Experiments show that the convex shape and the 40 nm sieve pores of the valves allow them to float on water, and that the buoyancy and the micro-range attractive forces cause the valves to assemble together at the highest point of water. As measured by AFM calibrated glass needles fixed in manipulator, the buoyancy force on a single floating valve may reach up to 10 μN in water. Turning the valves over, enlarging the sieve pores, reducing the surface tension of water, or vacuum pumping may cause the floating valves to sink. After the water has evaporated, the floating valves remained in their assembled state and formed a monolayer film. The bonded diatom monolayer may be valuable in studies on diatom based optical devices, biosensors, solar cells, and batteries, to better use the optical and adsorption properties of frustules. The floating assembly phenomenon can also be used as a self-assembly method for fabricating monolayer of circular plates. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. A study to estimate the fate and transport of bacteria in river water from birds nesting under a bridge.

    PubMed

    Nayamatullah, M M M; Bin-Shafique, S; Sharif, H O

    2013-01-01

    To investigate the effect of input parameters, such as the number of bridge-dwelling birds, decay rate of the bacteria, flow at the river, water temperature, and settling velocity, a parametric study was conducted using a water quality model developed with QUAL2Kw. The reach of the bacterial-impaired section from the direct droppings of bridge-nesting birds at the Guadalupe River near Kerrville, Texas was estimated using the model. The concentration of Escherichia coli bacteria were measured upstream, below the bridge, and downstream of the river for one-and-a-half years. The decay rate of the indicator bacteria in the river water was estimated from the model using measured data, and was found to be 6.5/day. The study suggests that the number of bridge-dwelling birds, the decay rate, and flow at the river have the highest impact on the fate and transport of bacteria. The water temperature moderately affects the fate and transport of bacteria, whereas, the settling velocity of bacteria did not show any significant effect. Once the decay rates are estimated, the reach of the impaired section was predicted from the model using the average flow of the channel. Since the decay rate does not vary significantly in the ambient environment at this location, the length of the impaired section primarily depends on flow.

  17. Reviewing the circulation and mixing of Antarctic Intermediate Water in the South Pacific using evidence from geochemical tracers and Argo float trajectories

    NASA Astrophysics Data System (ADS)

    Bostock, Helen C.; Sutton, Phil J.; Williams, Michael J. M.; Opdyke, Bradley N.

    2013-03-01

    Evidence from physical and geochemical tracers measured during the World Ocean Circulation Experiment (WOCE) shows that there are four sub-types of Antarctic Intermediate Water (AAIW) in the South Pacific. The main formation region of AAIW is the southeast Pacific, where fresh, cold, high oxygen, low nutrient, intermediate waters are created. This AAIW is transported north and mixes with Equatorial Pacific Intermediate Waters (EqPIW), themselves a combination of AAIW and nutrient rich, old North Pacific deep waters. 'Tasman' AAIW found in the Coral and Tasman Seas is more saline and warmer than the main subtropical gyre, and appears to have formed from mixing of AAIW with thermocline waters in the Tasman Gyre. Tasman AAIW leaks out of the Tasman basin to the north of New Zealand and along Chatham Rise, and also in the South Tasman Sea via the Tasman Leakage. Another source of relatively fresh, high oxygen, low nutrient, young AAIW comes directly from the Southern Ocean, flowing into the southwest and central South Pacific Basin, west of the East Pacific Rise. This 'Southern Ocean' (SO) AAIW is most likely a mixture of AAIW formed locally at the Subantarctic Front (SAF), and AAIW formed along the SAF in the southeast Pacific or Indian oceans and transported by the Antarctic Circumpolar Current (ACC). Interpreting physical and geochemical tracers, combined with velocity estimates from Argo floats, and previous research, has allowed us to refine the detailed circulation pattern of AAIW in the South Pacific, especially in the topographically complex southwest Pacific.

  18. Analysis of Vertical Dynamics in the Northern Baltic Sea based on 3D Modelling and Data from Shallow-Water Argo Floats

    NASA Astrophysics Data System (ADS)

    Westerlund, Antti; Tuomi, Laura

    2016-04-01

    Vertical mixing is a challenge for ocean models. 3D hydrodynamic models often produce considerable errors in mixed layer depths and vertical temperature structure that can be related to the vertical turbulence parameterisation. These errors can be pronounced in areas with complex hydrography. In the Baltic Sea, for example, there are high horizontal and vertical salinity gradients. Furthermore, thermocline and halocline are located at different depths. This produces stratification conditions challenging for all ocean models. We studied vertical mixing with modelling experiments and new observational data. NEMO 3D ocean model has been set up at Finnish Meteorological Institute (FMI) for the Baltic Sea, based on the NEMO Nordic configuration. The model has been discretized on a Baltic Sea - North Sea grid with 2 nautical mile resolution and 56 vertical layers, using FMI-HIRLAM atmospheric forcing. The observational data for Baltic Sea off-shore areas is sparse and new methods are needed to collect data for model validation and development. FMI has been testing Argo floats in the Baltic Sea since 2011 in order to increase the amount of observed vertical profiles of salinity and temperature. This is the first time Argo floats have been successfully used in the brackish, shallow waters of the Baltic Sea. This new data set is well suited for evaluating the capability of hydrodynamic models to produce the vertical structure of temperature. It provides a time series of profiles from the area of interest with good temporal resolution, showing the structure of temperature in the water column throughout the summer. We found that NEMO was able to reproduce the general features of the seasonal temperature variations in the study area, when meteorological forcing was accurate. We ran the model with different vertical turbulence parameterisations. The k-ɛ and k-ω schemes showed clear differences, but neither proved superior. While sea surface temperature was better simulated

  19. Preconcentration and speciation of arsenic in water specimens by the combination of solidification of floating drop microextraction and electrothermal atomic absorption spectrometry.

    PubMed

    Ghambarian, Mahnaz; Khalili-Zanjani, Mohammad Reza; Yamini, Yadollah; Esrafili, Ali; Yazdanfar, Najmeh

    2010-04-15

    A simple solidification of floating drop microextraction procedure for preconcentration and speciation of trace amounts of As(III) and As(V) in water samples has been proposed prior to electrothermal atomic absorption spectrometry (ETAAS). In this method, a free microdroplet of organic solvent is floated on the surface of aqueous solution while being agitated by a stirring bar placed on the bottom of the sample vial. The determination of As(III) was achieved by selective formation of the As(III)-pyrrolidine dithiocarbamate complex in the presence of 0.1M HCl while As(V) forms a weak complex with the ligand in the same pH conditions. Total inorganic As(III, V) was extracted similarly after reduction of As(V) to As(III) with potassium iodide and sodium thiosulfate and As(V) concentration was calculated by difference. Pd(NO(3))(2) was used as a chemical modifier in ETAAS. Some important extraction parameters such as the type of organic solvent, solvent volume, sample stirring rate, sample solution temperature, salt addition and the exposure time on the extraction recovery were investigated and optimized. Under the optimized extraction conditions, the detection limit of 9.2 pg mL(-1) and suitable precision (RSD<8.6%), along with enhancement factor of 1000 for As were achieved. The developed method was applied successfully to speciation of As(III), As(V) and determination of the total amount of As in water samples. (c) 2009 Elsevier B.V. All rights reserved.

  20. Ultrasound-air-assisted demulsified liquid-liquid microextraction by solidification of a floating organic droplet for determination of three antifungal drugs in water and biological samples.

    PubMed

    Ezoddin, Maryam; Shojaie, Mehran; Abdi, Khosrou; Karimi, Mohammad Ali

    2017-03-01

    A novel ultrasound-air-assisted demulsified liquid-liquid microextraction by solidification of a floating organic droplet (UAAD-LLM-SFO) followed by HPLC-UV detection was developed for the analysis of three antifungal drugs in water and biological samples. In this method, 1-dodecanol was used as the extraction solvent. The emulsion was rapidly formed by pulling in and pushing out the mixture of sample solution and extraction solvent for 5 times repeatedly using a 10-mL glass syringe while sonication was performed. Therefore, an organic dispersive solvent required in common microextraction methods was not used in the proposed method. After dispersing, an aliquot of acetonitrile was introduced as a demulsifier solvent into the sample solution to separate two phases. Therefore, some additional steps, such as the centrifugation, ultrasonication, or agitation of the sample solution, are not needed. Parameters influencing the extraction recovery were investigated. The proposed method showed a good linearity for the three antifungal drugs studied with the correlation coefficients (R (2) > 0.9995). The limits of detection (LODs) and the limits of the quantification (LOQs) were between 0.01-0.03 μg L(-1) and 0.03-0.08 μg L(-1), respectively. The preconcentration factors (PFs) were in the range of 107-116, respectively. The precisions, as the relative standard deviations (RSDs) (n = 5), for inter-day and intra-day analysis were in the range of 2.1-4.5% and 6.5-8.5%, respectively. This method was successfully applied to determine the three antifungal drugs in tap water and biological samples. The recoveries of antifungal drugs in these samples were 92.4-98.5%. Graphical abstract Ultrasound-air-assisted demulsified liquid-liquid microextraction by solidification of a floating organic droplet for the analysis of three antifungal drugs prior HPLC-UV.

  1. Dispersive liquid-liquid microextraction method based on solidification of floating organic droplet for the determination of thiamphenicol and florfenicol in environmental water samples.

    PubMed

    Peng, Guilong; He, Qiang; Al-Hamadani, Sulala M Z F; Zhou, Guangming; Liu, Mengzi; Zhu, Hui; Chen, Junhua

    2015-05-01

    Dispersive liquid-liquid microextraction with solidification of a floating organic droplet (DLLME-SFO) followed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection was applied for the determination of thiamphenicol (TAP), florfenicol (FF) in water samples. 1-Undecanol was used as the extraction solvent which has lower density than water, low toxicity, and low melting point (19°C). A mixture of 800mL acetone (disperser solvent) and 80µL of 1-undecanol (extraction solvent) was injected into 20mL of aqueous solution. After 5min, 0.6g of NaCl was added and the sample vial was shaken. After 5min, the sample was centrifuged at 3500rpm for 3min, and then placed in an ice bath. When the extraction solvent floating on the aqueous solution had solidified, it was transferred into another conical vial where it was melted quickly at room temperature, and was diluted with methanol to 1mL, and analyzed by HPLC-UV detection. Parameters influencing the extraction efficiency were thoroughly examined and optimized. The extraction recoveries (ER) and the enrichment factors (EF) ranged from 67% to 72% and 223 to 241, respectively. The limits of detection (LODs) (S/N=3) were 0.33 and 0.56µgL(-1) for TAP and FF, respectively. Linear dynamic range (LDR) was in the range of 1.0-550µgL(-1) for TAP and 1.5-700µgL(-1) for FF, the relative standard deviations (RSDs) were in the range of 2.6-3.5% and the recoveries of spiked samples ranged from 94% to 106%.

  2. Discrete Element Modelling of Floating Debris

    NASA Astrophysics Data System (ADS)

    Mahaffey, Samantha; Liang, Qiuhua; Parkin, Geoff; Large, Andy; Rouainia, Mohamed

    2016-04-01

    Flash flooding is characterised by high velocity flows which impact vulnerable catchments with little warning time and as such, result in complex flow dynamics which are difficult to replicate through modelling. The impacts of flash flooding can be made yet more severe by the transport of both natural and anthropogenic debris, ranging from tree trunks to vehicles, wheelie bins and even storage containers, the effects of which have been clearly evident during recent UK flooding. This cargo of debris can have wide reaching effects and result in actual flood impacts which diverge from those predicted. A build-up of debris may lead to partial channel blockage and potential flow rerouting through urban centres. Build-up at bridges and river structures also leads to increased hydraulic loading which may result in damage and possible structural failure. Predicting the impacts of debris transport; however, is difficult as conventional hydrodynamic modelling schemes do not intrinsically include floating debris within their calculations. Subsequently a new tool has been developed using an emerging approach, which incorporates debris transport through the coupling of two existing modelling techniques. A 1D hydrodynamic modelling scheme has here been coupled with a 2D discrete element scheme to form a new modelling tool which predicts the motion and flow-interaction of floating debris. Hydraulic forces arising from flow around the object are applied to instigate its motion. Likewise, an equivalent opposing force is applied to fluid cells, enabling backwater effects to be simulated. Shock capturing capabilities make the tool applicable to predicting the complex flow dynamics associated with flash flooding. The modelling scheme has been applied to experimental case studies where cylindrical wooden dowels are transported by a dam-break wave. These case studies enable validation of the tool's shock capturing capabilities and the coupling technique applied between the two numerical

  3. Large vortex-like structure of dipole field in computer models of liquid water and dipole-bridge between biomolecules.

    PubMed

    Higo, J; Sasai, M; Shirai, H; Nakamura, H; Kugimiya, T

    2001-05-22

    We propose a framework to describe the cooperative orientational motions of water molecules in liquid water and around solute molecules in water solutions. From molecular dynamics (MD) simulation a new quantity "site-dipole field" is defined as the averaged orientation of water molecules that pass through each spatial position. In the site-dipole field of bulk water we found large vortex-like structures of more than 10 A in size. Such coherent patterns persist more than 300 ps although the orientational memory of individual molecules is quickly lost. A 1-ns MD simulation of systems consisting of two amino acids shows that the fluctuations of site-dipole field of solvent are pinned around the amino acids, resulting in a stable dipole-bridge between side-chains of amino acids. The dipole-bridge is significantly formed even for the side-chain separation of 14 A, which corresponds to five layers of water. The way that dipole-bridge forms sensitively depends on the side-chain orientations and thereby explains the specificity in the solvent-mediated interactions between biomolecules.

  4. Large vortex-like structure of dipole field in computer models of liquid water and dipole-bridge between biomolecules

    PubMed Central

    Higo, Junichi; Sasai, Masaki; Shirai, Hiroki; Nakamura, Haruki; Kugimiya, Takaki

    2001-01-01

    We propose a framework to describe the cooperative orientational motions of water molecules in liquid water and around solute molecules in water solutions. From molecular dynamics (MD) simulation a new quantity “site-dipole field” is defined as the averaged orientation of water molecules that pass through each spatial position. In the site-dipole field of bulk water we found large vortex-like structures of more than 10 Å in size. Such coherent patterns persist more than 300 ps although the orientational memory of individual molecules is quickly lost. A 1-ns MD simulation of systems consisting of two amino acids shows that the fluctuations of site-dipole field of solvent are pinned around the amino acids, resulting in a stable dipole-bridge between side-chains of amino acids. The dipole-bridge is significantly formed even for the side-chain separation of 14 Å, which corresponds to five layers of water. The way that dipole-bridge forms sensitively depends on the side-chain orientations and thereby explains the specificity in the solvent-mediated interactions between biomolecules. PMID:11344268

  5. Effect of eco-remediation using planted floating bed system on nutrients and heavy metals in urban river water and sediment: a field study in China.

    PubMed

    Ning, Daliang; Huang, Yong; Pan, Ruisong; Wang, Fayuan; Wang, Hui

    2014-07-01

    To investigate the effect of the eco-remediation on nutrients and heavy metals in river water and sediment, a field study was carried out in a site of a 2-year eco-remediation mainly using planted floating bed system in an urban river in China. Before remediation, the tested properties of water and sediment in the will-be remediated area were not different from the control area, except higher concentrations of chemical oxygen demand (COD) and total nitrogen (TN) in the river water. After remediation, the remediation area showed effective removal of in-stream nutrients and elevation of dissolved oxygen and transparency. Compared to the control area, the remediation area had higher concentration of nitrate and lower concentrations of COD, ammonium, Mn and hexavalent Cr in the river water after a 2-year remediation. The remediation area also showed higher concentrations of organic carbon, TN, nitrate, sulfate, Fe, Cu, Pb and Zn in the sediment than in the control area. Accordingly, special attention should be paid to the ecological risk of heavy metals in sediments and plants in river eco-remediation projects especially in rivers polluted by heavy metals, although the metals were lower than the level of considerable ecological risk in this study.

  6. Modeling the soil system: Bridging the gap between pedology and soil-water physics

    NASA Astrophysics Data System (ADS)

    Braudeau, Erik; Mohtar, Rabi H.

    2009-05-01

    The biological and geochemical processes in soil such as organic matter mineralization, microbiological activity, and plant alimentation can be accurately assessed and modeled only with the knowledge of the thermodynamic status of the soil medium where these processes take place. However, current soil water models do not define and characterize the soil structure or the thermodynamic state of the soil water interacting with this structure. This article presents a new paradigm in characterizing and modeling the organized soil medium and the physical properties resulting from this organization. It describes a framework of the modeling approach as a contribution to the General Systems theory. The basic concept of Representative Elementary Volume (REV) in soil physics and hydrology was transformed into the concept of Structure Representative Volume (SREV) which takes into account the hierarchical organization of the structured soil medium. The pedostructure is defined as the SREV of the soil medium and this concept is at the basis of the new paradigm including variables, equations, parameters, and units in soil physics, in a similar way that the REV is at the basis of the continuous porous media mechanics applied to soils. The paradigm allows for a thermodynamic characterization of the structured soil medium with respect to soil water content then bridging the gap between pedology and soil physics. We show that the two points of view (REV and SREV) are complementary and must be used in the scaling of information. This approach leads to a new dimension in soil-water properties characterization that ensures a physically based modeling of processes in soil and the transfer of information from the physical scale of processes (pedostructure or laboratory measurements scale) to the application scale of the other disciplines (modeling and mapping scale).

  7. Solvated water molecules and hydrogen-bridged networks in liquid water

    NASA Astrophysics Data System (ADS)

    Corongiu, Giorgina; Clementi, Enrico

    1993-02-01

    We have analyzed the molecular-dynamics (MD) trajectories for the oxygen and hydrogen atoms of liquid water, at six temperatures (from hot, T=361 K, to supercooled water, T=242 K); in the MD simulations the Nieser-Corongiu-Clementi ab initio potential has been used, since it yields reliable x-ray and neutron-diffraction data as well as infrared, Raman, and neutron-scattering spectra. Our analysis leads to two complementary models where we can consider each water as a solvated molecule (placed at the center of a solvation shell) or as a component of a cyclic polymer, a substructure of the hydrogen-bonded network. In the first solvation shell all water molecules are solvated with coordination values in the range 2-8. The most probable solvation number is four, at low temperature, and five at high temperature considering oxygen-oxygen pairs; however, the coordination number is four at all the temperatures if we consider oxygen-hydrogen pairs. The lifetime of the tetra coordinated complexes is the largest one and increases as temperature decreases. The computed population of cyclic polymers is highest for the pentameters in the studied temperature range, the second most probable cyclic structure is for hexamers. The average O-O distances in the liquid are temperature dependent and shorter than those in the gas phase, approaching ice values at low temperature (except for cyclic trimers, for which the O-O distance is nearly temperature independent). As a preliminary result, the lifetime of the polygons is estimated to be around 0.01 ps.

  8. Thermodynamic properties of bridging clusters in thin films of water between hydrophobic surfaces assessed from surface force isotherms.

    PubMed

    Eriksson, Jan Christer; Henriksson, Ulf

    2013-04-16

    In the course of a long-term effort to cope with surface force data for thin films of water between hydrophobic surfaces, we have applied the bridging-cluster model (Eriksson, J. C.; Henriksson, U. Bridging-cluster model for hydrophobic attraction . Langmuir 2007, 23, 10026 - 10033) to the recently published surface force isotherms for water films between hexadecylthiolated gold surfaces in the thickness range of 20-100 nm and temperature range of 10-40 °C (Wang, J.; Yoon, R.-H.; Eriksson, J. C. Excess thermodynamic properties of thin water films confined between hydrophobized gold surfaces. J. Colloid Interface Sci. 2011, 364, 257 - 263). We show that these isotherms can be faithfully reproduced on the basis of the bridging-cluster model. The thermodynamic excess properties (ΔGc , ΔHc , and TΔSc) of linear clusters that are assumed to bridge the core of the films were calculated from the experimental surface force isotherms. A crucial step taken was to infer two-dimensional ideal mixing of the clusters with the surrounding film water. We find that ΔHc and TΔSc are both negative quantities, with the latter being larger than the former, which implies a positive excess Gibbs energy of a cluster, ΔGc = ΔHc - TΔSc. Typically, for temperatures between 10 and 40 °C, these cluster properties are of the order of some kBT units, corresponding to 10(-4)-10(-3)kBT per water molecule entailed. Our analysis yields support of the notion that elongated aggregates can arise in thin films of water between hydrophobic surfaces driven by entropy of mixing.

  9. Solidified floating organic drop microextraction combined with ETV-ICP-MS for the determination of trace heavy metals in environmental water samples.

    PubMed

    Guo, Xueqin; He, Man; Chen, Beibei; Hu, Bin

    2012-05-30

    A new method of solidified floating organic drop microextraction (SFODME) combined with electrothermal vaporization (ETV)-inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of trace heavy metals in environmental water samples with sodium diethyldithiocarbamate (DDTC) as both chelating reagent in SFODME and chemical modifier in ETV. The factors affecting the microextraction efficiency were studied in detail and the optimal extraction conditions were established. Under the optimal conditions, the limits of detection (LODs) for SFODME-ETV-ICP-MS determination of Co, Pd, Cd, Hg, Pb and Bi were found to be 0.0060, 0.0091, 0.0020, 0.0041, 0.0170 and 0.0041 ng mL(-1), respectively, with the relative standard deviations (RSDs) of 2.8-10.0% (c=0.5 ng mL(-1), n=7). The developed method was successfully applied to the analysis of six target metals in Yangtze River and East Lake water samples with recoveries ranging from 77.7 to 119.1%. To validate the accuracy of the method, a certified reference material of Environmental Water (GSBZ50009-88) was analyzed and the determined values were in good agreement with the certified values. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Determination of boron in water samples by dispersive liquid-liquid microextraction based on the solidification of a floating organic drop coupled with a fluorimetric method.

    PubMed

    Peng, Guilong; He, Qiang; Li, Haifang; Mmereki, Daniel; Lu, Ying; Zheng, Yongzan; Zhong, Zhihui; Lin, Jin-Ming

    2016-04-07

    In this work, a new, rapid and reliable method for the determination of boron in water samples by dispersive liquid-liquid microextraction based on the solidification of a floating organic drop (DLLME-SFO) prior to fluorescence spectra analysis was developed. As a result of its complexation with boric acid, the method relies on the enhancement of the fluorescence (λex = 350 nm, λem = 373 nm) of chromotropic acid. The influences of DLLME-SFO parameters, including the extraction solvent type and its volume, pH, the disperser solvent type and its volume, and salt effects were investigated. Under the optimized conditions, the limit of detection was 0.11 ng L(-1), with a preconcentration factor of 86 times. The calibration curve was linear in the range of 0-40 nM. The proposed method has also been successfully applied to analyze real water samples and the relative recoveries of water samples ranged from 86.9 to 93.2%.

  11. Roy D. Bridges Bridge

    NASA Image and Video Library

    2003-08-06

    Incoming KSC Director James W. Kennedy (left) and departing KSC Director Roy D. Bridges Jr. (center) view the new sign on the NASA Causeway naming the bridge for Bridges who is leaving KSC to become the director of NASA's Langley Research Center, Hampton, Va. At right is the 45th Space Wing Commander Brig. Gen. J. Gregory Pavlovich. The bridge spans the Banana River on the NASA Causeway and connects Kennedy Space Center and Cape Canaveral Air Force Station.

  12. The investigation of excited state proton transfer mechanism in water-bridged 7-azaindole.

    PubMed

    Zhang, Yong-Jia; Zhao, Jin-Feng; Li, Yong-Qing

    2016-01-15

    Based on the time-dependent density functional theory (TDDFT), the excited-state intermolecular proton transfer (ESIPT) mechanism of water-bridged 7-azaindole has been investigated theoretically. The calculations of primary bond lengths and the IR vibrational spectra between the S0 state and the S1 state that verified the intramolecular hydrogen bond were strengthened. The fact that reproduced experimental absorbance and fluorescence emission spectra well theoretically demonstrate that the TDDFT theory we adopted is reasonable and effective. In addition, intramolecular charge transfer based on the frontier molecular orbitals demonstrated the indication of the ESIPT reaction. The constructed potential energy curves of ground state and the first excited state based on keeping the H2···O3 and H6···N7 distances fixed at a series of values have been used to illustrate the ESIPT process. A relative lower barrier of 5.94 kcal/mol in the S1 state potential energy curve for type II (lower than that of 9.82 kcal/mol in the S1 state for type I) demonstrates that type II ESIPT process occurs firstly in 7Al-2H2O complex.

  13. Bridge-scour analysis using the water surface profile (WSPRO) model

    USGS Publications Warehouse

    Mueller, David S.; ,

    1993-01-01

    A program was developed to extract hydraulic information required for bridge-scour computations, from the Water-Surface Profile computation model (WSPRO). The program is written in compiled BASIC and is menu driven. Using only ground points, the program can compute average ground elevation, cross-sectional area below a specified datum, or create a Drawing Exchange Format (DXF) fie of cross section. Using both ground points ad hydraulic information form the equal-conveyance tubes computed by WSPRO, the program can compute hydraulic parameters at a user-specified station or in a user-specified subsection of the cross section. The program can identify the maximum velocity in a cross section and the velocity and depth at a user-specified station. The program also can identify the maximum velocity in the cross section and the average velocity, average depth, average ground elevation, width perpendicular to the flow, cross-sectional area of flow, and discharge in a subsection of the cross section. This program does not include any help or suggestions as to what data should be extracted; therefore, the used must understand the scour equations and associated variables to the able to extract the proper information from the WSPRO output.

  14. Biological evaluation of a novel water soluble sulphur bridged binuclear copper(II) thiosemicarbazone complex.

    PubMed

    Senthil Raja, Duraisamy; Bhuvanesh, Nattamai S P; Natarajan, Karuppannan

    2011-09-01

    The reaction of 2-oxo-1,2-dihydroquinoline-3-carbaldehyde 4(N,N)-dimethylthiosemicarbazone (HL) with copper(II) nitrate in methanol yielded water soluble [{Cu(L)(CH(3)OH)}(2)](NO(3))(2) · H(2)O. Structural analysis revealed that the complex consists of centrosymmetric binuclear entities containing square-pyramidal copper(II) ions bridged through the sulfur atoms. The spectroscopic experimental evidences strongly suggested that the ligand and complex could interact with calf thymus DNA (CT-DNA) through intercalation. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 plasmid DNA. The complex also exhibited a strong binding to bovine serum albumin (BSA) over the ligand. Investigations of antioxidative properties showed that the complex has strong radical scavenging properties. Further, the cytotoxic effect of the complex was examined on HeLa, Hep G2, and HEp-2, which showed that the complex exhibited substantial cytotoxic specificity on HeLa over the other two. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  15. Electron Paramagnetic Resonance Characterization of Dioxygen-Bridged Cobalt Dimers with Relevance to Water Oxidation.

    PubMed

    Stich, Troy A; McAlpin, J Gregory; Wall, Ryan M; Rigsby, Matthew L; Britt, R David

    2016-12-19

    A variety of metal oxides can catalyze the oxidation of water to molecular oxygen when polarized by a sufficiently high electrochemical potential. Minimizing the overpotential and increasing the rate of the oxygen-evolving reaction (OER) are key goals in making such materials a component of viable energy storage devices. However, the structural factors that imbue the metal oxides with their catalytic power are difficult to assess as these solids contain many distinct metal-ion sites, have a varying amount of defect sites within the lattice, and can be composed of multiple phases. In the present study, we determined the magnetic properties for a series of dimeric cobalt complexes in which the two metal centers are bridged by a dioxygen moiety. Our spectroscopically validated electronic structure description indicates that each species is best described as two Co(III) ions that are bound to a μ-η(1)η(1) superoxide ligand. Intriguingly, we found evidence that the two compounds that possess oxygen-evolving activity coordinate the superoxide ion in an unusual, nonplanar fashion. It appears as if the intermediately long Co···Co distance of 3.9 Å is responsible for the unusual superoxide binding geometry. This structural factor may be an important element in the design of solid-state OER catalysts.

  16. The First State in the Catalytic Cycle of the Water-Oxidizing Enzyme: Identification of a Water-Derived μ-Hydroxo Bridge.

    PubMed

    Lohmiller, Thomas; Krewald, Vera; Sedoud, Arezki; Rutherford, A William; Neese, Frank; Lubitz, Wolfgang; Pantazis, Dimitrios A; Cox, Nicholas

    2017-10-03

    Nature's water-splitting catalyst, an oxygen-bridged tetramanganese calcium (Mn4O5Ca) complex, sequentially activates two substrate water molecules generating molecular O2. Its reaction cycle is composed of five intermediate (Si) states, where the index i indicates the number of oxidizing equivalents stored by the cofactor. After formation of the S4 state, the product dioxygen is released and the cofactor returns to its lowest oxidation state, S0. Membrane-inlet mass spectrometry measurements suggest that at least one substrate is bound throughout the catalytic cycle, as the rate of (18)O-labeled water incorporation into the product O2 is slow, on a millisecond to second time scale depending on the S state. Here, we demonstrate that the Mn4O5Ca complex poised in the S0 state contains an exchangeable hydroxo bridge. On the basis of a combination of magnetic multiresonance (EPR) spectroscopies, comparison to biochemical models and theoretical calculations we assign this bridge to O5, the same bridge identified in the S2 state as an exchangeable fully deprotonated oxo bridge [Pérez Navarro, M.; et al. Proc. Natl. Acad. Sci. U.S.A. 2013, 110, 15561]. This oxygen species is the most probable candidate for the slowly exchanging substrate water in the S0 state. Additional measurements provide new information on the Mn ions that constitute the catalyst. A structural model for the S0 state is proposed that is consistent with available experimental data and explains the observed evolution of water exchange kinetics in the first three states of the catalytic cycle.

  17. 22. Float located adjacent to entry stair in filtration bed. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. Float located adjacent to entry stair in filtration bed. The float actuates a valve that maintains water level over the bed. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

  18. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Floating OCS facilities. 143.120 Section 143.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES DESIGN AND EQUIPMENT OCS Facilities § 143.120 Floating OCS...

  19. 33 CFR 144.01-1 - Life floats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Life floats. 144.01-1 Section 144.01-1 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES LIFESAVING APPLIANCES Manned Platforms § 144.01-1 Life floats. Each...

  20. Design, synthesis, and cercaricidal activity of novel high-efficient, low-toxic self-spreading PEG-N-salicylanilide derivatives against cercariae larvae of Schistosome Japonicum floating on the water surface.

    PubMed

    Guo, Wei; Zheng, Lv-Yin; Wu, Ren-Miao; Fan, Xiao-Lin

    2015-05-01

    Novel cercaricides of PEG-N-salicylanilide derivatives that could self-spread and float on the water surface were designed and synthesized according to the particular habit of cercariae larvae of Schistosome japonicum. The structures of the cercaricides were characterized by the infrared spectra (IR), magnetic resonance ((1) H NMR), and mass spectrum (MS). The images of the floating cercaricides on the water surface were investigated by the Brewster angle microscopy (BAM). When the cercaricides were dropped on the water surface, they could spread along the air-water interface automatically and form thin membranes floating on the water surface immediately. The lethality rate of cercariae for 5a and 6a was more than 90% in 120 min at a surface concentration of 0.008 mg/cm(2) . The non-ionic surfactant-cercaricides not only showed strong cercaricidal activities against the cercariae larvae but also exhibited low toxicities, which offered an effective and environment-friendly approach for the reduction of population infection rate and the realization of schistosome control. © 2014 John Wiley & Sons A/S.

  1. Excitation energies of a water-bridged twisted retinal structure in the bacteriorhodopsin proton pump: a theoretical investigation.

    PubMed

    Wolter, Tino; Welke, Kai; Phatak, Prasad; Bondar, Ana-Nicoleta; Elstner, Marcus

    2013-08-14

    The first proton transfer in the bacteriorhodopsin photocycle takes place during the L → M transition. Structural details of the pre proton transfer L intermediate have been investigated using experiments and computations. Here, we assess L-state structural models by performing hybrid quantum mechanical/molecular mechanical molecular dynamics and excitation energy calculations. The computations suggest that a water-bridged twisted retinal structure gives the closest agreement with the experimental L/bR shift in the excitation energy.

  2. Intergeneric coaggregation among drinking water bacteria: evidence of a role for Acinetobacter calcoaceticus as a bridging bacterium.

    PubMed

    Simões, Lúcia Chaves; Simões, Manuel; Vieira, Maria João

    2008-02-01

    Intergeneric coaggregation of drinking water bacteria was tested. Acinetobacter calcoaceticus was found not only to autoaggregate but also to coaggregate with four of the five other isolates (Burkholderia cepacia, Methylobacterium sp., Mycobacterium mucogenicum, Sphingomonas capsulata, and Staphylococcus sp.). In its absence, no coaggregation was found. Interactions were lectin-saccharide mediated. The putative bridging function of A. calcoaceticus was evidenced by multispecies biofilm studies, through a strain exclusion process.

  3. Float Zone Workshop

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.

    1980-01-01

    A summary of the Analytical Float Zone Experiment System (AFZES) concept is presented. The types of experiments considered for such a facility are discussed. Reports from various industrial producers and users of float zone material are presented. Special emphasis is placed on state-of-the-art developments in low gravity manufacturing and their applications to space processing.

  4. Floating patterns of metered dose inhalers.

    PubMed

    Wolf, B L; Cochran, K R

    1997-01-01

    As long as metered dose inhalers have existed, patients have sought a reliable method to determine if a given canister was still potent. Concerning beta agonists, the answer to this question may be lifesaving. Issues of compliance have made dating canisters or counting doses impractical. Likewise, previous claims of floating characteristics are unreliable. In tap water, we float-tested 13 commonly used inhalers three times each, observing variations as they were incrementally actuated, emptying their contents. One essential pattern was observed. Almost all prescription-size canisters sink when full; all float by the time one-third of their contents is gone. Orientation of prescription-size canisters changes in a distinct pattern especially near 90% depletion. Sample-size canisters showed some variance. Results suggest that the pharmaceutical industry should include individual floating characteristics as part of the package insert as they provide a reproducible means of gauging contents.

  5. Multipurpose floating platform for hyperspectral imaging, sampling and sensing of surface water sources used in irrigation and recreation

    USDA-ARS?s Scientific Manuscript database

    The objective of this work was to design, construct, and test the self-propelled aquatic platform for imaging, multi-tier water sampling, water quality sensing, and depth profiling to document microbial content and environmental covariates in the interior of irrigation ponds and reservoirs. The plat...

  6. Estimation of Bridge Height over Water from Polarimetric SAR Image Data Using Mapping and Projection Algorithm and De-Orientation Theory

    NASA Astrophysics Data System (ADS)

    Wang, Haipeng; Xu, Feng; Jin, Ya-Qiu; Ouchi, Kazuo

    An inversion method of bridge height over water by polarimetric synthetic aperture radar (SAR) is developed. A geometric ray description to illustrate scattering mechanism of a bridge over water surface is identified by polarimetric image analysis. Using the mapping and projecting algorithm, a polarimetric SAR image of a bridge model is first simulated and shows that scattering from a bridge over water can be identified by three strip lines corresponding to single-, double-, and triple-order scattering, respectively. A set of polarimetric parameters based on the de-orientation theory is applied to analysis of three types scattering, and the thinning-clustering algorithm and Hough transform are then employed to locate the image positions of these strip lines. These lines are used to invert the bridge height. Fully polarimetric image data of airborne Pi-SAR at X-band are applied to inversion of the height and width of the Naruto Bridge in Japan. Based on the same principle, this approach is also applicable to spaceborne ALOSPALSAR single-polarization data of the Eastern Ocean Bridge in China. The results show good feasibility to realize the bridge height inversion.

  7. Tank Tests of Two Floats for High-speed Seaplanes

    NASA Technical Reports Server (NTRS)

    Bell, Joe W

    1933-01-01

    At the request of the Bureau of Aeronautics, Navy Department, a study of the design of floats especially suitable for use on high-speed seaplanes was undertaken in the N.A.C.A. tank. This note give the results obtained in tests of one-quarter full-size models of two floats for high-speed seaplanes. One was a float similar to that used on the Macchi high-speed seaplane which competed in the 1926 Schneider Trophy races, and the other a float designed at the N.A.C.A. tank in an attempt to improve on the water performance of the Macchi float. The model of the latter showed considerably better water performance than the model of the Macchi float.

  8. Public Hearing and Comment Period Documents for the Northeast Gateway Energy Bridge Deepwater, Federal Waters of Massachusetts Bay (Modification to Existing Permit LNG Regasification Vessel/DWP Project)

    EPA Pesticide Factsheets

    List of public hearing & comment period document(s) for the Northeast Gateway Energy Bridge Deepwater Port, Federal Waters of Massachusetts Bay (Modification to Existing Permit LNG Regasification Vessel/DWP Project).

  9. Draft Permit & Supporting Documentation for the Northeast Gateway Energy Bridge Deepwater Port, Federal Waters of Massachusetts Bay (Modification to Existing Permit LNG Regasification Vessel/DWP Project)

    EPA Pesticide Factsheets

    List of draft permit & supporting documentation for the Northeast Gateway Energy Bridge Deepwater Port, Federal Waters of Massachusetts Bay (Modification to Existing Permit LNG Regasification Vessel/DWP Project).

  10. 33 CFR 144.01-5 - Location and launching of life floats.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Location and launching of life floats. 144.01-5 Section 144.01-5 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Location and launching of life floats. The life floats shall be distributed in accessible locations...

  11. 33 CFR 144.01-5 - Location and launching of life floats.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Location and launching of life floats. 144.01-5 Section 144.01-5 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Location and launching of life floats. The life floats shall be distributed in accessible locations...

  12. 33 CFR 144.01-5 - Location and launching of life floats.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Location and launching of life floats. 144.01-5 Section 144.01-5 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Location and launching of life floats. The life floats shall be distributed in accessible locations...

  13. 33 CFR 144.01-5 - Location and launching of life floats.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Location and launching of life floats. 144.01-5 Section 144.01-5 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Location and launching of life floats. The life floats shall be distributed in accessible locations...

  14. Long-term assessment at field scale of Floating Treatment Wetlands for improvement of water quality and provision of ecosystem services in a eutrophic urban pond.

    PubMed

    Olguín, Eugenia J; Sánchez-Galván, Gloria; Melo, Francisco J; Hernández, Víctor J; González-Portela, Ricardo E

    2017-04-15

    Pollution of urban water bodies requires stringent control measures and the development of low-cost and highly efficient alternative technologies. In contrast to Constructed Wetlands, Floating Treatment Wetlands (FTWs) have the advantage of not requiring large surface of land since they operate in situ. However, there is limited information about their long-term evaluation while operating at field scale. The aim of this work was to assess the performance of FTWs using a combination of Pontederia sagittata and Cyperus papyrus for the improvement of the water quality and provision of ecosystem services of a eutrophic urban pond. The FTWs were built with low-cost material easy to acquire and to ensemble. Two FTWs (17.5m(2) and 33m(2)) located in Pond 1 within a complex of 4 urban artificial ponds were evaluated for two years. They promoted an increase in the dissolved oxygen (D.O.) within a range of 15 to 67%, a removal of fecal coliforms in the range of 9 to 86% and a nitrate removal in the range of 9 to 76%. The plant productivity reached a maximum of 363gdmm(-2)d(-1) in the FTW1 and 536gdmm(-2)d(-1) in the FTW2 during the period March-June 2016. The TKN and the TP content in the plant were in the range of 18.3 to 28.1 and of 0.05 to 0.196gkg(-1) dry matter, respectively. In conclusion, the tested FTWs have proved to be a very beneficial low-cost technology for the improvement of water quality and provision of ecosystem services.

  15. Dispersive liquid-liquid microextraction method based on solidification of floating organic droplet for the determination of triazine herbicides in water and sugarcane samples.

    PubMed

    Sanagi, Mohd Marsin; Abbas, Hana Hassan; Ibrahim, Wan Aini Wan; Aboul-Enien, Hassan Y

    2012-07-15

    Dispersive liquid-liquid microextraction method based on solidification of floating organic droplet (DLLME-SFO) was developed for the analysis of triazines. As model compounds four selected triazine herbicides namely, simazine, atrazine, secbumeton and cyanazine were employed to estimate the extraction efficiency. The experimental conditions were comprehensively studied for the DLLME-SFO method. Under the use of 10 μL of 1-undecanol as extraction solvent, 100 μL of acetonitrile as disperser solvent and 5% (w/v) NaCl for 3 min the results demonstrated that the repeatability (RSD%) of the optimised DLLME-SFO method ranged from 0.03% to 5.1% and the linearity in the range of 0.01-100 ppb. Low limits of detection (0.037-0.008 ppb), and good enrichment factors (195-322) were obtained. The DLLME-SFO method applied in water and sugarcane samples showed excellent relative recoveries (95.7-116.9%) with RSDs <8.6% (n=3) for all samples.

  16. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which do...

  17. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which do...

  18. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which do...

  19. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which do...

  20. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which do...

  1. Roy D. Bridges Bridge

    NASA Image and Video Library

    2003-08-06

    From left, incoming KSC Director James W. Kennedy looks on as departing KSC Director Roy D. Bridges Jr. shakes hands with the 45th Space Wing Commander Brig. Gen. J. Gregory Pavlovich. The occasion is the unveiling of the new sign on the NASA Causeway naming the bridge for Bridges who is leaving KSC to become the director of NASA's Langley Research Center, Hampton, Va. The bridge spans the Banana River on the NASA Causeway and connects Kennedy Space Center and Cape Canaveral Air Force Station.

  2. Floating--A Key to Survival.

    ERIC Educational Resources Information Center

    Anderson, Norman

    1980-01-01

    Described are several activities to be used to help students grasp the concept of floating. The activities include the use of a spring scale to measure the weight of the objects in air, in water, and in salt water, and a discussion of why there are differences in these weights. (DS)

  3. Water-quality assessment of stormwater runoff from a heavily used urban highway bridge in Miami, Florida

    USGS Publications Warehouse

    McKenzie, Donald J.; Irwin, G.A.

    1983-01-01

    Runoff from a heavily-traveled, 1.43-acre bridge section of Interstate-95 in Miami, Florida, was comprehensively monitored for both quality and quantity during five selected storms between November 1979 and May 1981. For most water-quality parameters, 6 to 11 samples were collected during each of the 5 runoff events. Concentrations of most parameters in the runoff were quite variable both during individual storm events and among the five storm events; however, the ranges in parameter concentration were about the same magnitude report for numerous other highway and urban drainages. Data were normalized to estimate the average, discharge-weighted parameter loads per storm per acre of bridge surface and results suggested that the most significant factor influencing stormwater loads was parameter concentration. Rainfall intensity and runoff volume, however, influenced rates of loading. The total number of antecedent dry days and traffic volume did not appear to be conspicously related to either runoff concentrations or loads. (USGS)

  4. Floating emitter solar cell

    NASA Technical Reports Server (NTRS)

    Chih, Sah (Inventor); Cheng, Li-Jen (Inventor)

    1987-01-01

    A front surface contact floating emitter solar cell transistor is provided in a semiconductor body (n-type), in which floating emitter sections (p-type) are diffused or implanted in the front surface. Between the emitter sections, a further section is diffused or implanted in the front surface, but isolated from the floating emitter sections, for use either as a base contact to the n-type semiconductor body, in which case the section is doped n+, or as a collector for the adjacent emitter sections.

  5. Recorded seismic response of a base-isolated steel bridge carrying a steel water pipe

    USGS Publications Warehouse

    Safak, E.; Brady, A.G.

    1989-01-01

    A set of strong motion records was obtained from the base-isolated Santa Ana River Pipeline Bridge during the magnitude 5.9 Whittier Narrows, California, earthquake of October 1, 1987. The analysis of the records show that the level of excitation was not strong enough to fully activate the base isolators. The dominant modes of the response are the translations of the abutment-bridge-pipe system in the longitudinal and transverse directions, and the bending of the steel truss between supports in the vertical direction.

  6. Floating wind turbine system

    NASA Technical Reports Server (NTRS)

    Viterna, Larry A. (Inventor)

    2009-01-01

    A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

  7. Skylab floating ice experiment

    NASA Technical Reports Server (NTRS)

    Campbell, W. J. (Principal Investigator); Ramseier, R. O.; Weaver, R. J.; Weeks, W. F.

    1975-01-01

    The author has identified the following significant results. Coupling of the aircraft data with the ground truth observations proved to be highly successful with interesting results being obtained with IR and SLAR passive microwave techniques, and standard photography. Of particular interest were the results of the PMIS system which operated at 10.69 GHz with both vertical and horizontal polarizations. This was the first time that dual polarized images were obtained from floating ice. In both sea and lake ice, it was possible to distinguish a wide variety of thin ice types because of their large differences in brightness temperatures. It was found that the higher brightness temperature was invariably obtained in the vertically polarized mode, and as the age of the ice increases the brightness temperature increases in both polarizations. Associated with this change in age, the difference in temperature was observed as the different polarizations decreased. It appears that the horizontally polarized data is the most sensitive to variations in ice type for both fresh water and sea ice. The study also showed the great amount of information on ice surface roughness and deformation patterns that can be obtained from X-band SLAR observations.

  8. Hydrodynamic Tests of Models of Seaplane Floats

    NASA Technical Reports Server (NTRS)

    Eula, Antonio

    1935-01-01

    This report contains the results of tank tests carried out at free trim on seventeen hulls and floats of various types. The data as to the weight on water, trim, and relative resistance for each model are plotted nondimensionally and are referenced both to the total weight and to the weight on water. Despite the fact that the experiments were not made systematically, a study of the models and of the test data permits nevertheless some general deductions regarding the forms of floats and their resistance. One specific conclusion is that the best models have a maximum relative resistance not exceeding 20 percent of the total weight.

  9. Micromechanisms with floating pivot

    DOEpatents

    Garcia, Ernest J.

    2001-03-06

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use floating pivot structures to relieve some of the problems encountered in the use of solid flexible pivots.

  10. Floating Magnet Demonstration.

    ERIC Educational Resources Information Center

    Wake, Masayoshi

    1990-01-01

    A room-temperature demonstration of a floating magnet using a high-temperature superconductor is described. The setup and operation of the apparatus are described. The technical details of the effect are discussed. (CW)

  11. Commercial Float Zone Furnace

    NASA Image and Video Library

    1996-05-25

    S77-E-5094 (25 May 1996) --- Astronaut Marc Garneau, mission specialist representing the Canadian Space Agency (CSA), stands at the Commercial Float Zone Furnace (CFZF) in the Spacehab Module onboard the Earth-orbiting Space Shuttle Endeavour.

  12. Floating Magnet Demonstration.

    ERIC Educational Resources Information Center

    Wake, Masayoshi

    1990-01-01

    A room-temperature demonstration of a floating magnet using a high-temperature superconductor is described. The setup and operation of the apparatus are described. The technical details of the effect are discussed. (CW)

  13. The Floating Reference Librarian

    ERIC Educational Resources Information Center

    Hernon, Peter; Pastine, Maureen

    1972-01-01

    The floating librarian'' is one who interprets and adjusts the formal library structure to meet legitimate needs. This is one of the ways the academic reference librarian can gain greater acceptance with students and faculty. (9 references) (Author/NH)

  14. Reducing float coal dust

    PubMed Central

    Patts, J.R.; Colinet, J.F.; Janisko, S.J.; Barone, T.L.; Patts, L.D.

    2016-01-01

    Controlling float coal dust in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more effective and efficient use of rock dust. A prototype flooded-bed scrubber was evaluated for float coal dust control in the return of a continuous miner section. The scrubber was installed inline between the face ventilation tubing and an exhausting auxiliary fan. Airborne and deposited dust mass measurements were collected over three days at set distances from the fan exhaust to assess changes in float coal dust levels in the return due to operation of the scrubber. Mass-based measurements were collected on a per-cut basis and normalized on the basis of per ton mined by the continuous miner. The results show that average float coal dust levels measured under baseline conditions were reduced by more than 90 percent when operating the scrubber. PMID:28018004

  15. Stabilized floating platforms

    DOEpatents

    Thomas, David G.

    1976-01-01

    The subject invention is directed to a floating platform for supporting nuclear reactors and the like at selected offshore sites. The platform is provided with a stabilizer mechanism which significantly reduces the effects of wave action upon the platform and which comprises a pair of relatively small floats attached by rigid booms to the platform at locations spaced therefrom for reducing wave pitch, acceleration, and the resonance period of the wave.

  16. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats and their attachments and supporting structures must be designed for the conditions prescribed in this section. In the cases specified...

  17. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats and their attachments and supporting structures must be designed for the conditions prescribed in this section. In the cases specified...

  18. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats and their attachments and supporting structures must be designed for the conditions prescribed in this section. In the cases specified...

  19. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats and their attachments and supporting structures must be designed for the conditions prescribed in this section. In the cases specified...

  20. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats and their attachments and supporting structures must be designed for the conditions prescribed in this section. In the cases specified...

  1. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .... The resultant water load must be applied in the plane of symmetry of the float at a point three... r y=ratio of the lateral distance between the center of gravity and the plane of symmetry of the... the plane of symmetry of the float at a point one-fourth of the distance from the bow to the step...

  2. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... The resultant water load must be applied in the plane of symmetry of the float at a point three... r y=ratio of the lateral distance between the center of gravity and the plane of symmetry of the... the plane of symmetry of the float at a point one-fourth of the distance from the bow to the step...

  3. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... The resultant water load must be applied in the plane of symmetry of the float at a point three... r y=ratio of the lateral distance between the center of gravity and the plane of symmetry of the... the plane of symmetry of the float at a point one-fourth of the distance from the bow to the step...

  4. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... The resultant water load must be applied in the plane of symmetry of the float at a point three... r y=ratio of the lateral distance between the center of gravity and the plane of symmetry of the... the plane of symmetry of the float at a point one-fourth of the distance from the bow to the step...

  5. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .... The resultant water load must be applied in the plane of symmetry of the float at a point three... r y=ratio of the lateral distance between the center of gravity and the plane of symmetry of the... the plane of symmetry of the float at a point one-fourth of the distance from the bow to the step...

  6. Operation Bridge: Over the Troubled Waters of Adult Education. Transcript [and] Evaluation Plan.

    ERIC Educational Resources Information Center

    Bowers, Robert F.

    Operation Bridge, a program which was developed by the Detroit Public Schools to train 13 adult advisors to work with adult education students in outreach sites and traditional adult education centers, is described. The selection process, the orientation, the coursework, the internships, and the application of training are discussed. The report on…

  7. Crossing the Water: Spiritual Growth in "Bridge to Terabithia" and "Lizzie Bright and the Buckminster Boy"

    ERIC Educational Resources Information Center

    Thomas, Trudelle

    2011-01-01

    The author analyses two award-winning juvenile novels, "Bridge to Terabithia" by Katherine Paterson and "Lizzie Bright and the Buckminster Boy" by Gary Schmidt. Each novel portrays a deep friendship between a boy and girl who cross a stream (or river) into a world that includes fantasy, play, closeness to nature and animals, and a sense of the…

  8. Crossing the Water: Spiritual Growth in "Bridge to Terabithia" and "Lizzie Bright and the Buckminster Boy"

    ERIC Educational Resources Information Center

    Thomas, Trudelle

    2011-01-01

    The author analyses two award-winning juvenile novels, "Bridge to Terabithia" by Katherine Paterson and "Lizzie Bright and the Buckminster Boy" by Gary Schmidt. Each novel portrays a deep friendship between a boy and girl who cross a stream (or river) into a world that includes fantasy, play, closeness to nature and animals, and a sense of the…

  9. Wave drag on floating bodies

    PubMed Central

    Le Merrer, Marie; Clanet, Christophe; Quéré, David; Raphaël, Élie; Chevy, Frédéric

    2011-01-01

    We measure the deceleration of liquid nitrogen drops floating at the surface of a liquid bath. On water, the friction force is found to be about 10 to 100 times larger than on a solid substrate, which is shown to arise from wave resistance. We investigate the influence of the bath viscosity and show that the dissipation decreases as the viscosity is increased, owing to wave damping. The measured resistance is well predicted by a model imposing a vertical force (i.e., the drop weight) on a finite area, as long as the wake can be considered stationary. PMID:21876186

  10. Revisiting the vulnerability of juvenile bigeye (Thunnus obesus) and yellowfin (T. albacares) tuna caught by purse-seine fisheries while associating with surface waters and floating objects.

    PubMed

    Scutt Phillips, Joe; Pilling, Graham M; Leroy, Bruno; Evans, Karen; Usu, Thomas; Lam, Chi Hin; Schaefer, Kurt M; Nicol, Simon

    2017-01-01

    Tuna fisheries catch over three million tonnes of skipjack tuna (Katsuwonus pelamis) each year, the majority of which come from purse-seine vessels targeting fish associated with man-made fish aggregating devices (FADs). A significant challenge for fisheries management is to maximize the efficiency of skipjack tuna catches whilst minimizing the bycatch of small and immature bigeye (Thunnus obesus) and yellowfin (T. albacares) tuna, for which long-term sustainability is uncertain in 75% of the world's stocks. To better manage the issues common with this fishing method, an improved understanding of tuna behaviour around FADs is necessary. We probabilistically classified the vertical behavioural patterns of 50 bigeye and 35 yellowfin tuna (mean fork length 72cm and 70cm, respectively) electronically tagged throughout the western and central Pacific Ocean into shallow and deep states, using a state-space modelling approach. The occurrence of surface-association behaviours, defined as an individual remaining in a shallow state for 24-hours, was examined in relation to known capture events and FAD density. In general, surface-association events for both species were short and lasted on average less than three days, although events as long as 28 days were observed, and were more common in yellowfin when in archipelagic waters. Events were longest immediately following tagging in 62% and 17% of bigeye and yellowfin, respectively. Surface-association behaviour was not generally estimated just prior to recapture, being either non-existent or shorter than two days for 85% of bigeye and 74% of yellowfin. Current management measures in purse-seine tuna fisheries involve periodic or spatial closures for FAD use. If the chief benefit to purse-seine fishers of surface-association around floating objects is in locating schools in horizontal space at short-term time-scales, rather than holding fish near the surface for extended periods, controlling the number of sets made on FADs

  11. Capabilities and limitations of dispersive liquid-liquid microextraction with solidification of floating organic drop for the extraction of organic pollutants from water samples.

    PubMed

    Vera-Avila, Luz E; Rojo-Portillo, Tania; Covarrubias-Herrera, Rosario; Peña-Alvarez, Araceli

    2013-12-17

    Dispersive liquid-liquid microextraction with solidification of floating organic drop (DLLME-SFO) is one of the most interesting sample preparation techniques developed in recent years. Although several applications have been reported, the potentiality and limitations of this simple and rapid extraction technique have not been made sufficiently explicit. In this work, the extraction efficiency of DLLME-SFO for pollutants from different chemical families was determined. Studied compounds include: 10 polycyclic aromatic hydrocarbons, 5 pesticides (chlorophenoxy herbicides and DDT), 8 phenols and 6 sulfonamides, thus, covering a large range of polarity and hydrophobicity (LogKow 0-7, overall). After optimization of extraction conditions using 1-dodecanol as extractant, the procedure was applied for extraction of each family from 10-mL spiked water samples, only adjusting sample pH as required. Absolute recoveries for pollutants with LogKow 3-7 were >70% and recovery values within this group (18 compounds) were independent of structure or hydrophobicity; the precision of recovery was very acceptable (RSD<12%) and linear behavior was observed in the studied concentration range (r(2)>0.995). Extraction recoveries for pollutants with LogKow 1.46-2.8 were in the range 13-62%, directly depending on individual LogKow values; however, good linearity (r(2)>0.993) and precision (RSD<6.5%) were also demonstrated for these polar solutes, despite recovery level. DLLME-SFO with 1-dodecanol completely failed for extraction of compounds with LogKow≤1 (sulfa drugs), other more polar extraction solvents (ionic liquids) should be explored for highly hydrophilic pollutants. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. A novel route towards water-soluble luminescent iridium(iii) complexes via a hydroxy-bridged dinuclear precursor.

    PubMed

    Scarpelli, Francesca; Ionescu, Andreea; Ricciardi, Loredana; Plastina, Pierluigi; Aiello, Iolinda; La Deda, Massimo; Crispini, Alessandra; Ghedini, Mauro; Godbert, Nicolas

    2016-11-01

    The synthesis and photophysical characterization of a new family of luminescent water-soluble ionic iridium(iii) complexes of the general formula [(ppy)2Ir(bpy)]X are reported. The Ir(iii) complexes incorporate a cyclometalated 2-phenylpyridine (ppy), the ancillary ligand 2,2'-bipyridyl (bpy) and different counterions (X(-) = EtO(-), OH(-), EtOCH2CO2(-), MeOCH2CO2(-)). These complexes were obtained starting from the cyclometalated Ir(iii) chloro-bridged dimer [(ppy)2Ir(μ-Cl)]2, for the first time synthesized through a new microwave assisted synthetic procedure, and subsequently converted into the corresponding hydroxy-bridged dimer [(ppy)2Ir(μ-OH)]2. The latter was eventually used as a sole reagent for the synthesis of all the reported complexes by simply varying the nature of the reaction solvent from water to alcohols and glycol ethers. This study demonstrates the versatility of the [(ppy)2Ir(μ-OH)]2 complex as a precursor to water soluble ionic Ir(iii) complexes. Indeed, [(ppy)2Ir(μ-OH)]2 has shown its peculiar chemical reactivity due to both a strong base character and an unexpected oxidative ability towards the alcoholic function of glycol ethers. All the synthesized complexes exhibit, in water solution, an orange emission centred at 606 nm. Moreover, all complexes display the ability to give rise to gel phases in water upon increasing their concentration, and the photophysical study evidenced the various interactions governing the gelification process. The water-solubility of these new luminescent Ir(iii) complexes makes them potentially useful in bio-related systems.

  13. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Retroreflective panels on bridge... SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.100 Retroreflective panels on bridge piers. The... 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge...

  14. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Retroreflective panels on bridge... SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.100 Retroreflective panels on bridge piers. The... 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge...

  15. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Retroreflective panels on bridge... SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.100 Retroreflective panels on bridge piers. The... 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge...

  16. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Retroreflective panels on bridge... SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.100 Retroreflective panels on bridge piers. The... 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge...

  17. 33 CFR 118.100 - Retroreflective panels on bridge piers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Retroreflective panels on bridge... SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.100 Retroreflective panels on bridge piers. The... 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge...

  18. 33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false ExxonMobil Hoover Floating OCS... Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos... (1640.4 feet) from each point on the structure's outer edge is a safety zone. (b) Regulation. No vessel...

  19. 33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false ExxonMobil Hoover Floating OCS... Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos... (1640.4 feet) from each point on the structure's outer edge is a safety zone. (b) Regulation. No vessel...

  20. 33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false ExxonMobil Hoover Floating OCS... Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos... (1640.4 feet) from each point on the structure's outer edge is a safety zone. (b) Regulation. No vessel...

  1. 33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false ExxonMobil Hoover Floating OCS... Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos... (1640.4 feet) from each point on the structure's outer edge is a safety zone. (b) Regulation. No vessel...

  2. 33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false ExxonMobil Hoover Floating OCS... Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos... (1640.4 feet) from each point on the structure's outer edge is a safety zone. (b) Regulation. No vessel...

  3. The collection of clear-water contraction and abutment scour data at selected bridge sites in the coastal plain and piedmont of South Carolina

    USGS Publications Warehouse

    Benedict, Stephen T.; Caldwell, Andy W.; Edited by Abt, S. R. and others

    1998-01-01

    Clear-water contraction and abutment scour data were collected at 128 bridge sites in South Carolina. In the sandy soils of the Coastal Plain, clear-water-scour data were collected at 63 sites (scour depths ranged from 0.4 to 7.2 meters.) In the clayey soils of the Piedmont, clear-water-scour data were collected at 47 sites (scour depths ranged from 0 to 1.4 meters.) In the sandy, clayey soils of the Piedmont, clear-water-scour data were collected at 18 sites (scour depths ranged from 0.9 to 5.5 meters.) The field data are to be compiled into a data base that will include bridge age; basin, soil and hydraulic characteristics; and theoretical scour data. The data are planned to be statistically analyzed for significant relations that may help explain and (or) predict maximum scour depths at bridges in South Carolina.

  4. Surface Drift of RAFOS Floats in the California Current System

    NASA Astrophysics Data System (ADS)

    Gates, D. C.; Collins, C. A.; Margolina, T.

    2011-12-01

    The patterns of surface drift of ninety RAFOS floats in the California Current System have been studied. The floats were launched in the California Undercurrent during 1992-2010 and were tracked by the ARGOS system when they surfaced at the end of their subsurface mission. The float hulls were glass cylinders which were 8.6 cm wide by 1.52 m long and floated with the upper 30 cm of the hull above water. The surface drift of these floats was typically equatorward in the California Current. However, some floats would flow poleward, others would drift westward into the North Pacific Gyre, and others with orbital cyclonic and/or anti-cyclonic motions. The duration of surface trajectories varied from as short as a period of days to approximately ten months. Forces on the floats included wind stress on the exposed hull and the drag of ocean currents on the subsurface hull. The latter included the Stokes drift associated with surface wind waves, Ekman flow caused by the stress of the wind on the ocean surface, and the currents associated with the general circulation of the ocean. Surface currents can be explained by calculating current direction and velocity from wind stress data. As a first step, the relationship between observed wind stress and the motion of the float is determined by assuming Ekman balance. Mesoscale effects, including eddies, are also considered in explaining the surface drift of the floats.

  5. Detection of Air and Water-Filled Subsurface Defects in GFRP Composite Bridge Decks Using Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Halabe, Udaya B.; Roy, M.; Klinkhachorn, P.; GangaRao, Hota V. S.

    2006-03-01

    Any discontinuity within a structural component influences the transmission of thermal energy through its thickness, which leads to differences in surface temperatures just above the defective and defect-free areas. The variation in the surface temperatures are recorded using a digital infrared camera and the thermal images (thermograms) are analyzed to locate the presence of subsurface defects such as debonds and delaminations within the structure. While past studies focused on detection of air-filled subsurface defects (debonds and delaminations) in fiber reinforced polymer (GFRP) composite bridge decks using infrared thermography, this paper includes the detection of fully and partially water-filled defects as well. Simulated water-filled defects were embedded within the flange-to-flange junction of adjacent GFRP bridge deck modules to create delaminations. The deck specimens were then tested before and after the application of a 3/8″ (9.5 mm) thick polymer concrete wearing surface. It was found that water-filled delaminations as small as 2″ × 2″ × 1/16″ (51 mm × 51 mm × 1.6 mm) could be detected in case of specimens without wearing surface, but this was not possible after application of the wearing surface. The heating source considered included heater and solar radiation. Use of cooling sources such as cold water and liquid carbon dioxide were also explored. These results helped establish the limits of detection for fully and partially water-filled delaminations using Infrared Thermograpy. Additional studies included the detection of debond between 2″ (51mm) thick asphalt overlay and the underlying composite deck and it was found that air-filled debonds as small as 4″ × 4″ × 1/16″ (102 mm × 102 mm × 1.6 mm) could be detected using heater as well as solar radiation as heat sources.

  6. Valuing water quality in urban watersheds: A comparative analysis of Johnson Creek, Oregon, and Burnt Bridge Creek, Washington

    NASA Astrophysics Data System (ADS)

    Netusil, Noelwah R.; Kincaid, Michael; Chang, Heejun

    2014-05-01

    This study uses the hedonic price method to investigate the effect of five water quality parameters on the sale price of single-family residential properties in two urbanized watersheds in the Portland, Oregon-Vancouver, Washington metropolitan area. Water quality parameters include E. coli or fecal coliform, which can affect human health, decrease water clarity and generate foul odors; pH, dissolved oxygen, and stream temperature, which can impact fish and wildlife populations; and total suspended solids, which can affect water clarity, aquatic life, and aesthetics. Properties within ¼ mile, ½, mile, one mile, or more than one mile from Johnson Creek are estimated to experience an increase in sale price of 13.71%, 7.05%, 8.18%, and 3.12%, respectively, from a one mg/L increase in dissolved oxygen levels during the dry season (May-October). Estimates for a 100 count per 100 mL increase in E. coli during the dry season are -2.81% for properties within ¼ mile of Johnson Creek, -0.86% (½ mile), -1.19% (one mile), and -0.71% (greater than one mile). Results for properties in Burnt Bridge Creek include a significantly positive effect for a one mg/L increase in dissolved oxygen levels during the dry season for properties within ½ mile (4.49%), one mile (2.95%), or greater than one mile from the creek (3.17%). Results for other water quality parameters in Burnt Bridge Creek are generally consistent with a priori expectations. Restoration efforts underway in both study areas might be cost justified based on their estimated effect on property sale prices.

  7. 14 CFR 23.757 - Auxiliary floats.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Auxiliary floats. 23.757 Section 23.757 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... fresh water, they provide a righting moment of at least 1.5 times the upsetting moment caused by the...

  8. Bridge permeameter

    DOEpatents

    Graf, Darin C.; Warpinski, Norman R.

    1996-01-01

    A system for single-phase, steady-state permeability measurements of porous rock utilizes a fluid bridge arrangement analogous to a Wheatstone bridge. The arms of the bridge contain the sample and calibrated flow resistors.

  9. In Brief: Profiling floats fully deployed

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2007-11-01

    The Argo network of sensor-bearing profiling floats, which allows scientists to observe the basic physical state of the world's oceans, reached its full deployment of 3000 units on 1 November, according to the Argo steering committee. With the full deployment of these floats-which measure ocean water temperature, salinity, and velocity-data from every ocean region are available with an average coverage of one sensor per 3 degrees of latitude and longitude. The floats drift on ocean currents for 10 days, descend to up to 2000 meters in depth, and return to the surface to beam results to passing satellites. ``The climate science objectives that drive the Argo array require that we observe the global oceans indefinitely, so achieving the global array is merely the beginning of the observation period,'' said Dean Roemmich, cochairman of the Argo program steering committee and a physical oceanographer at the Scripps Institution of Oceanography.

  10. Floating mechanism of a small liquid marble

    PubMed Central

    Ooi, Chin Hong; Plackowski, Chris; Nguyen, Anh V.; Vadivelu, Raja K.; John, James A. St.; Dao, Dzung Viet; Nguyen, Nam-Trung

    2016-01-01

    Flotation of small solid objects and liquid droplets on water is critical to natural and industrial activities. This paper reports the floating mechanism of liquid marbles, or liquid droplets coated with hydrophobic microparticles. We used X-ray computed tomography (XCT) to acquire cross-sectional images of the floating liquid marble and interface between the different phases. We then analysed the shape of the liquid marble and the angles at the three-phase contact line (TPCL). We found that the small floating liquid marbles follow the mechanism governing the flotation of solid objects in terms of surface tension forces. However, the contact angles formed and deformation of the liquid marble resemble that of a sessile liquid droplet on a thin, elastic solid. For small liquid marbles, the contact angle varies with volume due to the deformability of the interface. PMID:26902930

  11. Floating nut retention system

    NASA Technical Reports Server (NTRS)

    Charles, J. F.; Theakston, H. A. (Inventor)

    1980-01-01

    A floating nut retention system includes a nut with a central aperture. An inner retainer plate has an opening which is fixedly aligned with the nut aperture. An outer retainer member is formed of a base plate having an opening and a surface adjacent to a surface of the inner retainer plate. The outer retainer member includes a securing mechanism for retaining the inner retainer plate adjacent to the outer retainer member. The securing mechanism enables the inner retainer plate to float with respect to the outer retainer number, while simultaneously forming a bearing surface for inner retainer plate.

  12. Characterization of cement float buoyancy in the stalked barnacle Dosima fascicularis (Crustacea, Cirripedia)

    PubMed Central

    Zheden, Vanessa; Kovalev, Alexander; Gorb, Stanislav N.; Klepal, Waltraud

    2015-01-01

    Dosima fascicularis is the only barnacle which can drift autonomously at the water surface with a foam-like cement float. The cement secreted by the animal contains numerous gas-filled cells of different size. When several individuals share one float, their size and not their number is crucial for the production of both volume and mass of the float. The gas content within the cells of the foam gives positive static buoyancy to the whole float. The volume of the float, the gas volume and the positive static buoyancy are positively correlated. The density of the cement float without gas is greater than that of seawater. This study shows that the secreted cement consists of more than 90% water and the gas volume is on average 18.5%. Our experiments demonstrate that the intact foam-like cement float is sealed to the surrounding water. PMID:25657839

  13. Characterization of cement float buoyancy in the stalked barnacle Dosima fascicularis (Crustacea, Cirripedia).

    PubMed

    Zheden, Vanessa; Kovalev, Alexander; Gorb, Stanislav N; Klepal, Waltraud

    2015-02-06

    Dosima fascicularis is the only barnacle which can drift autonomously at the water surface with a foam-like cement float. The cement secreted by the animal contains numerous gas-filled cells of different size. When several individuals share one float, their size and not their number is crucial for the production of both volume and mass of the float. The gas content within the cells of the foam gives positive static buoyancy to the whole float. The volume of the float, the gas volume and the positive static buoyancy are positively correlated. The density of the cement float without gas is greater than that of seawater. This study shows that the secreted cement consists of more than 90% water and the gas volume is on average 18.5%. Our experiments demonstrate that the intact foam-like cement float is sealed to the surrounding water.

  14. 5. GENERAL VIEW LOOKING NORTHWEST. FENDER PREVENTS FLOATING DEBRIS FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. GENERAL VIEW LOOKING NORTHWEST. FENDER PREVENTS FLOATING DEBRIS FROM DAMAGING TRUSSES DURING PERIODS OF HIGH WATER. - Ohio & Erie Canal, Tinker's Creek Aqueduct, Canal Road, South Tinkers Creek Road, Valley View, Cuyahoga County, OH

  15. Floated gravity gradiometer and method

    SciTech Connect

    Lautzenhiser, T.V.; Eisner, M.

    1990-09-11

    This patent describes a gravity gradiometer. It comprises: a housing containing a fluid; a float buoyantly supported within the fluid; means for varying the metacentric height of the float; and means for obtaining a measure of the gravitational gradient acting on the float resulting from varying the metacentric height.

  16. Tethered float liquid level sensor

    SciTech Connect

    Daily, III, William Dean

    2016-09-06

    An apparatus for sensing the level of a liquid includes a float, a tether attached to the float, a pulley attached to the tether, a rotation sensor connected to the pulley that senses vertical movement of said float and senses the level of the liquid.

  17. Three Bridge Fryer's Ford Bridge, Nimrod Bridge, and Ward's ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Three Bridge - Fryer's Ford Bridge, Nimrod Bridge, and Ward's Crossing Bridge - Fryer's Ford Bridge, Spanning East Fork of Point Remove Creek at Fryer Bridge Road (CR 67), Solgohachia, Conway County, AR

  18. Molecular Dynamics of a Hydrated Collagen Peptide: Insights into Rotational Motion and Residence Times of Single-Water Bridges in Collagen.

    PubMed

    Tourell, Monique C; Momot, Konstantin I

    2016-12-15

    Magnetic resonance transverse spin relaxation time constants (T2) of water protons in ordered collagenous tissues are dependent on the orientation of the tissue relative to the static magnetic field. This dependence is commonly referred to as the magic angle (MA) effect and has been attributed to the restricted rotational motion of icelike water bridges in the hydrated triple-helix collagen molecule. Understanding of the molecular mechanism of the MA effect is important for clinical and research applications of magnetic resonance spectroscopy and imaging to tissues, such as articular cartilage, tendons, and ligaments. In this work, we have used molecular dynamics simulations to investigate the subnanosecond time scale dynamics of single-water bridges in a model collagen peptide. We ascertain the residence times and the patterns of restricted rotational motion of water molecules. The key findings are strongly anisotropic rotation patterns of water molecules at bridge sites and a dynamic, rather than icelike, nature of the single-water bridges within the individual triple-helix collagen molecule.

  19. Compound floating pivot micromechanisms

    DOEpatents

    Garcia, Ernest J.

    2001-04-24

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

  20. Thomas floats through Zvezda

    NASA Image and Video Library

    2005-07-28

    S114-E-5588 (28 July 2005) --- Astronaut Andrew S.W. Thomas may be reminiscing about his long duration stay aboard Russia's late Mir space station as he floats about the International Space Station during STS-114 flight day three activities.

  1. Commercial Float Zone Furnace

    NASA Image and Video Library

    1996-05-25

    S77-E-5093 (25 May 1996) --- Astronaut Marc Garneau, mission specialist representing the Canadian Space Agency (CSA), makes a visual check of the Commercial Float Zone Furnace (CFZF), a single-rack-mounted facility in the Spacehab Module onboard the Earth-orbiting Space Shuttle Endeavour. The scene was recorded with an Electronic Still Camera (ESC).

  2. The floating anchored craniotomy.

    PubMed

    Gutman, Matthew J; How, Elena; Withers, Teresa

    2017-01-01

    The "floating anchored" craniotomy is a technique utilized at our tertiary neurosurgery institution in which a traditional decompressive craniectomy has been substituted for a floating craniotomy. The hypothesized advantages of this technique include adequate decompression, reduction in the intracranial pressure, obviating the need for a secondary cranioplasty, maintained bone protection, preventing the syndrome of the trephined, and a potential reduction in axonal stretching. The bone plate is re-attached via multiple loosely affixed vicryl sutures, enabling decompression, but then ensuring the bone returns to its anatomical position once cerebral edema has subsided. From the analysis of 57 consecutive patients analyzed at our institution, we have found that the floating anchored craniotomy is comparable to decompressive craniectomy for intracranial pressure reduction and has some significant theoretical advantages. Despite the potential advantages of techniques that avoid the need for a second cranioplasty, they have not been widely adopted and have been omitted from trials examining the utility of decompressive surgery. This retrospective analysis of prospectively collected data suggests that the floating anchored craniotomy may be applicable instead of decompressive craniectomy.

  3. Why Do Things Float?

    ERIC Educational Resources Information Center

    Selley, Nicholas

    1993-01-01

    Combines two strands: one being an exposition of the variety of explanations which are given for the phenomenon of floating; the other being the pedagogical implications which arise from the use of alternative models in science. Attention is drawn to the ethical questions that may arise when primary science seems to conflict with accepted…

  4. Pipe-type cable floated into place across river

    SciTech Connect

    Not Available

    1994-07-01

    In 1992, the 60-yr-old Portland Bridge across the Fore River in Maine had to be replaced with a completely new structure. Unfortunately for Central Maine Power Co, three 34.5-kV submarine cables and a 115-kV pipe-type cable (plus spare pipe), which paralleled the old structure, were directly in the path planned for the footing of the new bridge. Before construction could begin, these had to be relocated to the other side of the old bridge. Because of space limitations in the crossing area, the two 1200-ft replacement pipes were assembled one mile upstream and floated down to the bridge using specially made polystyrene floats. The trench, measuring 20 ft wide and 20 ft deep, was dredged across the river bottom and designed to accommodate both the submarine and pipe-type cables with adequate spacing. First, the two pipes were floated into position and sunk into the trench. Then the three submarine cables were laid simultaneously from a cable barge. Divers ensured that there was adequate spacing between the medium- and high-voltage cables. 10 figs.

  5. Optimization of dispersive liquid-liquid microextraction based on the solidification of floating organic droplets using an orthogonal array design and its application for the determination of fungicide concentrations in environmental water samples.

    PubMed

    Yang, Xiaoling; Yang, Miyi; Hou, Bang; Li, Songqing; Zhang, Ying; Lu, Runhua; Zhang, Sanbing

    2014-08-01

    A dispersive liquid-liquid microextraction method based on the solidification of floating organic droplets was developed as a simple and sensitive method for the simultaneous determination of the concentrations of multiple fungicides (triazolone, chlorothalonil, cyprodinil, and trifloxystrobin) in water by high-performance liquid chromatography with variable-wavelength detection. After an approach varying one factor at a time was used, an orthogonal array design [L25 (5(5))] was employed to optimize the method and to determine the interactions between the parameters. The significance of the effects of the different factors was determined using analysis of variance. The results indicated that the extraction solvent volume significantly affects the efficiency of the extraction. Under optimal conditions, the relative standard deviation (n = 5) varied from 2.3 to 5.5% at 0.1 μg/mL for each analyte. Low limits of detection were obtained and ranged from 0.02 to 0.2 ng/mL. In addition, the proposed method was applied to the analysis of fungicides in real water samples. The results show that the dispersive liquid-liquid microextraction based on the solidification of floating organic droplets is a potential method for detecting fungicides in environmental water samples, with recoveries of the target analytes ranging from 70.1 to 102.5%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Bridging Water Issue Knowledge Gaps between the General Public and Opinion Leaders

    ERIC Educational Resources Information Center

    Lamm, Kevan W.; Lamm, Alexa J.; Carter, Hannah S.

    2015-01-01

    Global conflicts have rapidly made water the most contentious issue in the world today. Considering water drives health, industry, recreation, and the agricultural food system it is no surprise that it has become such a hot topic. As a result, the general public has an increased interest in water-focused policy; policy that can have a large impact…

  7. Transparent and Dense Ladder-Like Alkylene-Bridged Polymethylsiloxane Coating with Enhanced Water Vapor Barrier Property.

    PubMed

    Zhang, Ce; Zhang, Cong; Cui, Xinmin; Sun, Jinghua; Ding, Ruimin; Zhang, Qinghua; Xu, Yao

    2015-10-14

    Organic-inorganic hybrid composites have been well-studied as water vapor barrier materials for their long diffusion length of water vapor in coatings which can be realized by improving the aspect ratio of inorganic components and regularity of nanostructure in coatings. In this paper, dense organic-inorganic hybrid coating based on ladder-like alkylene-bridged polymethylsiloxane (ABPMS) was successfully fabricated through the hydrosilylation reaction between polymethylhydrosiloxane and diene (1,5-hexadiene or 1,7-octadiene) in toluene under Pt/C catalysis. Its ladder-like structure was verified by 29Si magic angle spinning (MAS) NMR, 13C MAS NMR, and in-plane and out-of-plane glance-incident X-ray diffraction (GIXRD) techniques. Its corresponding coating showed excellent water vapor barrier ability for a typical water-soluble crystal, potassium dihydrogen phosphate (KDP). When treated in 50% relative humidity (RH) condition at 25 °C for 8 months, the ABPMS coating with 100 nm thickness displayed a very low transmittance loss of 1.6% compared with the high transmittance loss of 10% for uncoated KDP. Moreover, the ABPMS coating showed good ultraviolet radiation resistance, thermal stability, low mechanical property, and excellent compatibility with hydrophobic antireflective (AR) coatings.

  8. Hydrodynamic and Aerodynamic Tests of Models of Floats for Single-float Seaplanes NACA Models 41-D, 41-E, 61-A, 73, and 73-A

    NASA Technical Reports Server (NTRS)

    Parkinson, J B; HOUSE R O

    1938-01-01

    Tests were made in the NACA tank and in the NACA 7 by 10 foot wind tunnel on two models of transverse step floats and three models of pointed step floats considered to be suitable for use with single float seaplanes. The object of the program was the reduction of water resistance and spray of single float seaplanes without reducing the angle of dead rise believed to be necessary for the satisfactory absorption of the shock loads. The results indicated that all the models have less resistance and spray than the model of the Mark V float and that the pointed step floats are somewhat superior to the transverse step floats in these respects. Models 41-D, 61-A, and 73 were tested by the general method over a wide range of loads and speeds. The results are presented in the form of curves and charts for use in design calculations.

  9. 1D and 3D inversion of VES data to outline a fresh water zone floating over saline water body at the northwestern coast of Egypt

    NASA Astrophysics Data System (ADS)

    Massoud, Usama; Soliman, Mamdouh; Taha, Ayman; Khozym, Ashraf; Salah, Hany

    2015-12-01

    Seawater intrusion is a widespread environmental problem in the Egyptian coastal aquifers. It affects the groundwater used in domestic and agricultural activities along these coasts. In this study, resistivity survey in the form of Vertical Electrical Sounding (VES) was conducted at ZAWYET EL HAWALA cultivated site, northwest coast of Egypt to outline a freshwater zone overlies the main saltwater body, and to determine the most suitable location for drilling water well for irrigation purposes. The VES data were measured at 11 stations in the studied site. After processing, the data were inverted in 1-D and 3-D schemes and the final model was presented as resistivity slices with depth. The results indicate that the effect of saltwater intrusion was observed, as low resistivity values, at 7.5 m below ground surface (bgs) at the northern part of the study area (toward the Mediterranean Sea), and extends southward with increasing depth covering the whole area at about 30 m bgs. The fresh water zone shows a minimum thickness of less than 7.5 m at the northern side and a maximum thickness of about 20 m at the southern side of the area. The proper site for drilling water well tap and the freshwater zone is the location of VES6 or VES9 with a maximum well depth of about 20 m bgs. The water withdrawal from the proposed well should be controlled not to raise the main saline water table in the well site. The main sources of the freshwater zone are the rainfall and surface runoff descending from the southern tableland. Excess rainfall and surface runoff can be avoided from direct discharge to the sea by collecting them in man-made outlined trenches and re-using the stored water in irrigation during the dry seasons.

  10. Bridging the Gap: Ideas for water sustainability in the western United States

    NASA Astrophysics Data System (ADS)

    Tidwell, V. C.; Passell, H. D.; Roach, J. D.

    2012-12-01

    Incremental improvements in water sustainability in the western U.S. may not be able to close the growing gap between increasing freshwater demand, climate driven variability in freshwater supply, and growing environmental consciousness. Incremental improvements include municipal conservation, improvements to irrigation technologies, desalination, water leasing, and others. These measures, as manifest today in the western U.S., are successful in themselves but limited in their ability to solve long term water scarcity issues. Examples are plainly evident and range from the steady and long term decline of important aquifers and their projected inability to provide water for future agricultural irrigation, projected declines in states' abilities to meet legal water delivery obligations between states, projected shortages of water for energy production, and others. In many cases, measures that can close the water scarcity gap have been identified, but often these solutions simply shift the gap from water to some other sector, e.g., economics. Saline, brackish or produced water purification, for example, could help solve western water shortages in some areas, but will be extremely expensive, and so shift the gap from water to economics. Transfers of water out of agriculture could help close the water scarcity gap in other areas; however, loss of agriculture will shift the gap to regional food security. All these gaps, whether in water, economics, food security, or other sectors, will have a negative impact on the western states. Narrowing these future gaps requires both technical and policy solutions as well as tools to understand the tradeoffs. Here we discuss several examples from across the western U.S. that span differing scales and decision spaces. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear

  11. Bridging the gap between uncertainty analysis for complex watershed models and decision-making for watershed-scale water management

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Han, F.; Wu, B.

    2013-12-01

    Process-based, spatially distributed and dynamic models provide desirable resolutions to watershed-scale water management. However, their reliability in solving real management problems has been seriously questioned, since the model simulation usually involves significant uncertainty with complicated origins. Uncertainty analysis (UA) for complex hydrological models has been a hot topic in the past decade, and a variety of UA approaches have been developed, but mostly in a theoretical setting. Whether and how a UA could benefit real management decisions remains to be critical questions. We have conducted a series of studies to investigate the applicability of classic approaches, such as GLUE and Markov Chain Monte Carlo (MCMC) methods, in real management settings, unravel the difficulties encountered by such methods, and tailor the methods to better serve the management. Frameworks and new algorithms, such as Probabilistic Collocation Method (PCM)-based approaches, were also proposed for specific management issues. This presentation summarize our past and ongoing studies on the role of UA in real water management. Challenges and potential strategies to bridge the gap between UA for complex models and decision-making for management will be discussed. Future directions for the research in this field will also be suggested. Two common water management settings were examined. One is the Total Maximum Daily Loads (TMDLs) management for surface water quality protection. The other is integrated water resources management for watershed sustainability. For the first setting, nutrients and pesticides TMDLs in the Newport Bay Watershed (Orange Country, California, USA) were discussed. It is a highly urbanized region with a semi-arid Mediterranean climate, typical of the western U.S. For the second setting, the water resources management in the Zhangye Basin (the midstream part of Heihe Baisn, China), where the famous 'Silk Road' came through, was investigated. The Zhangye

  12. 40 CFR 63.1043 - Standards-Separator floating roof.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) National Emission Standards for Oil-Water Separators and Organic-Water Separators § 63.1043 Standards... controlling air emissions from an oil-water separator or organic-water separator using a floating roof. (b... device in the closed position. (ii) To remove accumulated sludge or other residues from the bottom of...

  13. Validation of Capillarity Theory at the Nanometer Scale by Atomistic Computer Simulations of Water Droplets and Bridges in Contact with Hydrophobic and Hydrophilic Surfaces

    NASA Astrophysics Data System (ADS)

    Giovambattista, Nicolas; Almeida, Alexandre; Alenkar, Adriano; Buldyrev, Sergey

    Capillarity is the study of interfaces between two immiscible liquids or between a liquid and a vapor. Capillarity theory (CT) was created in the early 1800s and it is applicable to macroscopic (>1 μm) systems. In general, macroscopic theories are expected to fail at <10 nm scales where molecular details may become relevant. We show that, surprisingly, CT provides satisfactory predictions at 210 nm scales. Specifically, we perform atomistic molecular dynamics (MD) simulations of water droplets and capillary bridges of different symmetry in contact with various surfaces. The surfaces correspond to hydroxilated silica, modified to cover a wide range of hydrophobicity/hydrophilicity. In agreement with CT, it is found that (i) water contact angle is independent of the droplet/bridge geometry and depends only on the surface employed; (ii) CT provides the correct droplet/bridge profile for all hydrophobic/hydrophilic surfaces considered; and, remarkably, (iii) CT works even for the very small droplets/bridges studied, for which the smallest dimension is ~2 nm. We confirm the self-consistency of CT at 210 nm scales by calculating the capillary forces between different surfaces induced by capillary bridges; the agreement between MD simulations and CT theory is remarkable

  14. 33 CFR 115.70 - Advance approval of bridges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges prior...

  15. 33 CFR 115.70 - Advance approval of bridges.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges prior...

  16. 33 CFR 115.70 - Advance approval of bridges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges prior...

  17. 33 CFR 115.70 - Advance approval of bridges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges prior...

  18. 33 CFR 115.70 - Advance approval of bridges.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges prior...

  19. BRIDGE OVER TROUBLED WATERS? THE MOST "CENTRAL" MEMBERS OF PSYCHOLOGY AND PHILOSOPHY ASSOCIATIONS CA. 1900.

    PubMed

    Green, Christopher D; Heidari, Crystal; Chiacchia, Daniel; Martin, Shane M

    2016-07-01

    There are many different ways to assess the significance of historical figures. Often we look at the influence of their writings, or at the important offices they held with disciplinary institutions such as universities, journals, and scholarly societies. In this study, however, we took a novel approach: we took the complete memberships, ca. 1900, of four organizations-the American Psychological Association, the Western Philosophical Association, the American Philosophical Association, and the Southern Society for Philosophy and Psychology-and visualized them as a network. We then identified individuals who "bridged" between two or more of these groups and considered what might be termed their "centrality" to the psychological-philosophical community of their time. First, we examined these figures qualitatively, briefly describing their lives and careers. Then we approached the problem mathematically, considering several alternative technical realizations of "centrality" and then explaining our reasons for choosing eigenvector centrality as the best for our purposes. We found a great deal of overlap among the results of the qualitative and quantitative approaches, but also some telling differences. J. Mark Baldwin, Edward Buchner, Christine Ladd Franklin, and Frank Thilly consistently emerged as highly central figures. Some more marginal figures such as Max Meyer, and Frederick J. E. Woodbridge, Edward A. Pace, Edward H. Griffin played interesting roles as well. © 2016 Wiley Periodicals, Inc.

  20. Bridge over troubled waters: understanding the synthetic and biological identities of engineered nanomaterials.

    PubMed

    Fadeel, Bengt; Feliu, Neus; Vogt, Carmen; Abdelmonem, Abuelmagd M; Parak, Wolfgang J

    2013-01-01

    Engineered nanomaterials offer exciting opportunities for 'smart' drug delivery and in vivo imaging of disease processes, as well as in regenerative medicine. The ability to manipulate matter at the nanoscale enables many new properties that are both desirable and exploitable, but the same properties could also give rise to unexpected toxicities that may adversely affect human health. Understanding the physicochemical properties that drive toxicological outcomes is a formidable challenge as it is not trivial to separate and, hence, to pinpoint individual material characteristics of nanomaterials. In addition, nanomaterials that interact with biological systems are likely to acquire a surface corona of biomolecules that may dictate their biological behavior. Indeed, we propose that it is the combination of material-intrinsic properties (the 'synthetic identity') and context-dependent properties determined, in part, by the bio-corona of a given biological compartment (the 'biological identity') that will determine the interactions of engineered nanomaterials with cells and tissues and subsequent outcomes. The delineation of these entwined 'identities' of engineered nanomaterials constitutes the bridge between nanotoxicological research and nanomedicine.

  1. Float level switch for a nuclear power plant containment vessel

    DOEpatents

    Powell, J.G.

    1993-11-16

    This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel. 1 figures.

  2. Float level switch for a nuclear power plant containment vessel

    DOEpatents

    Powell, James G.

    1993-01-01

    This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel.

  3. Water safety plans: bridges and barriers to implementation in North Carolina.

    PubMed

    Amjad, Urooj Quezon; Luh, Jeanne; Baum, Rachel; Bartram, Jamie

    2016-10-01

    First developed by the World Health Organization, and now used in several countries, water safety plans (WSPs) are a multi-step, preventive process for managing drinking water hazards. While the beneficial impacts of WSPs have been documented in diverse countries, how to successfully implement WSPs in the United States remains a challenge. We examine the willingness and ability of water utility leaders to implement WSPs in the US state of North Carolina. Our findings show that water utilities have more of a reactive than preventive organizational culture, that implementation requires prioritization of time and resources, perceived comparative advantage to other hazard management plans, leadership in implementation, and identification of how WSPs can be embedded in existing work practices. Future research could focus on whether WSP implementation provides benefits such as decreases in operational costs, and improved organization of records and communication.

  4. Dual function photocatalysis of cyano-bridged heteronuclear metal complexes for water oxidation and two-electron reduction of dioxygen to produce hydrogen peroxide as a solar fuel.

    PubMed

    Aratani, Yusuke; Suenobu, Tomoyoshi; Ohkubo, Kei; Yamada, Yusuke; Fukuzumi, Shunichi

    2017-03-25

    The photocatalytic production of hydrogen peroxide from water and dioxygen under visible light irradiation was made possible by using polymeric cyano-bridged heteronuclear metal complexes (M(II)[Ru(II)(CN)4(bpy)]; M(II) = Ni(II), Fe(II) and Mn(II)), where the photocatalytic two-electron reduction of O2 and water oxidation were catalysed by the Ru and M(II) moieties, respectively.

  5. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  6. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  7. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  8. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  9. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

  10. FLOPAK: FLOATING POINT PROGRAMING PACKAGE,

    DTIC Science & Technology

    FLOPAK is a Packard-Bell 250 Computer semi-automatic, floating - point programing system which may be operated simultaneously in either of two modes...250 floating - point system available which may be used in real-time control. The system was originally designed to solve a real-time communication problem....The first is a non-time optimized mode which may be used by inex perienced coders; the second mode is a high-speed, fully time-optimized floating

  11. 33 CFR 147.847 - Safety Zone; BW PIONEER Floating Production, Storage, and Offloading System Safety Zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Safety Zone; BW PIONEER Floating... ZONES § 147.847 Safety Zone; BW PIONEER Floating Production, Storage, and Offloading System Safety Zone. (a) Description. The BW PIONEER, a Floating Production, Storage and Offloading (FPSO) system, is in...

  12. 33 CFR 147.847 - Safety Zone; BW PIONEER Floating Production, Storage, and Offloading System Safety Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Safety Zone; BW PIONEER Floating... ZONES § 147.847 Safety Zone; BW PIONEER Floating Production, Storage, and Offloading System Safety Zone. (a) Description. The BW PIONEER, a Floating Production, Storage and Offloading (FPSO) system, is in...

  13. 33 CFR 147.847 - Safety Zone; BW PIONEER Floating Production, Storage, and Offloading System Safety Zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Safety Zone; BW PIONEER Floating... ZONES § 147.847 Safety Zone; BW PIONEER Floating Production, Storage, and Offloading System Safety Zone. (a) Description. The BW PIONEER, a Floating Production, Storage and Offloading (FPSO) system, is in...

  14. 14 CFR 25.527 - Hull and main float load factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... float load factors. (a) Water reaction load factors n W must be computed in the following manner: (1... following values are used: (1) n W=water reaction load factor (that is, the water reaction divided...

  15. Optimal plant water use across temporal scales: bridging eco-hydrological theories and plant eco-physiological responses

    NASA Astrophysics Data System (ADS)

    Manzoni, S.; Vico, G.; Palmroth, S.; Katul, G. G.; Porporato, A. M.

    2013-12-01

    In terrestrial ecosystems, plant photosynthesis occurs at the expense of water losses through stomata, thus creating an inherent hydrologic constrain to carbon (C) gains and productivity. While such a constraint cannot be overcome, evolution has led to a number of adaptations that allow plants to thrive under highly variable and often limiting water availability. It may be hypothesized that these adaptations are optimal and allow maximum C gain for a given water availability. A corollary hypothesis is that these adaptations manifest themselves as coordination between the leaf photosynthetic machinery and the plant hydraulic system. This coordination leads to functional relations between the mean hydrologic state, plant hydraulic traits, and photosynthetic parameters that can be used as bridge across temporal scales. Here, optimality theories describing the behavior of stomata and plant morphological features in a fluctuating soil moisture environment are proposed. The overarching goal is to explain observed global patterns of plant water use and their ecological and biogeochemical consequences. The problem is initially framed as an optimal control problem of stomatal closure during drought of a given duration, where maximizing the total photosynthesis under limited and diminishing water availability is the objective function. Analytical solutions show that commonly used transpiration models (in which stomatal conductance is assumed to depend on soil moisture) are particular solutions emerging from the optimal control problem. Relations between stomatal conductance, vapor pressure deficit, and atmospheric CO2 are also obtained without any a priori assumptions under this framework. Second, the temporal scales of the model are expanded by explicitly considering the stochasticity of rainfall. In this context, the optimal control problem becomes a maximization problem for the mean photosynthetic rate. Results show that to achieve maximum C gains under these

  16. Bridge permeameter

    DOEpatents

    Graf, D.C.; Warpinski, N.R.

    1996-08-13

    A system is described for single-phase, steady-state permeability measurements of porous rock which utilizes a fluid bridge arrangement analogous to a Wheatstone bridge. The arms of the bridge contain the sample and calibrated flow resistors. 8 figs.

  17. Bridging the Rubicon: phylogenetic analysis reveals repeated colonizations of marine and fresh waters by thalassiosiroid diatoms.

    PubMed

    Alverson, Andrew J; Jansen, Robert K; Theriot, Edward C

    2007-10-01

    Salinity imposes a significant barrier to the distribution of many organisms, including diatoms. Diatoms are ancestrally marine, and the number of times they have independently colonized fresh waters and the physiological adaptations that facilitated these transitions remain outstanding questions in diatom evolution. The colonization of fresh waters by diatoms has been compared to "crossing the Rubicon," implying that successful colonization events are rare, irreversible, and lead to substantial species diversification. To test these hypotheses, we reconstructed the phylogeny of Thalassiosirales, a diatom lineage with high diversity in both marine and fresh waters. We collected approximately 5.3kb of DNA sequence data from the nuclear (SSU and partial LSU rDNA) and chloroplast genomes (psbC and rbcL) and reconstructed the phylogeny using parsimony and Bayesian methods. Alternative topology tests strongly reject all previous colonization hypotheses, including monophyly of the predominantly freshwater Stephanodiscaceae. Results showed at least three independent colonizations of fresh waters, and whereas previous accounts of freshwater-to-marine transitions have been discounted, these results provide compelling evidence for as many as three independent re-colonizations of the marine habitat, two of which led to speciation events. This study adds valuable phylogenetic context to previous debate about the nature of the salinity barrier in diatoms and provides compelling evidence that, at least for Thalassiosirales, the salinity barrier might be less formidable than previously thought.

  18. Bridging the Gap Between Climate Science and Water-resource Applications

    NASA Astrophysics Data System (ADS)

    Arnold, J. R.; Clark, M. P.; Wood, A.; Gutmann, E. D.; Nijssen, B.; Brekke, L. D.

    2015-12-01

    Since 2010, the US Army Corps of Engineers (USACE) Climate Preparedness and Resilience Program has supported development of a coordinated system of products and tools to improve use of climate information in water-resource planning and management. The key products include: 1) a new understanding of the limitations of methods used to quantify impacts of climate change on water resources; 2) development and evaluation of national-domain climate downscaling and hydrologic simulation capabilities to provide information from climate model output relevant to the multiple scales of water resources decision-making with a spatially consistent assessment of the impacts of climate change on hydrologic conditions; and 3) development and evaluation of advanced streamflow forecasting methods. This will support USACE Districts and their stakeholders and partners with new data, new and newly evaluated model output, and specific tools in a framework to help with routine applications for managing water resources throughout the U.S., and to enhance considerations of climate preparedness and resilience in that work. This presentation will summarize the collaborative development of some of those products; describe current and planned future USACE capabilities for incorporating advanced climate information at multiple scales of analysis and decision; discuss uses of climate information in water-resources planning and management; and outline key unanswered science questions being addressed to increase utility and use of information in short- and longer-term planning. Specifically, we will describe the current suite and planned trajectory of new products, moving from capability development through to testing in limited pilot domains, on to product applications throughout the U.S., and, ultimately, into actual implementation at the level of USACE Districts to address climate change issues. Two key foci of this talk will be: 1) where climatological and hydrologic science is currently

  19. Bridging the climate-induced water gap in the twenty-first century: adaptation support based on water supply, demand, adaptation and financing.

    NASA Astrophysics Data System (ADS)

    Straatsma, Menno; Droogers, Peter; Brandsma, Jaïrus; Buytaert, Wouter; Karssenberg, Derek; Van Beek, Rens; Wada, Yoshihide; Sutanudjaja, Edwin; Vitolo, Claudia; Schmitz, Oliver; Meijer, Karen; Van Aalst, Maaike; Bierkens, Marc

    2014-05-01

    realistic combinations of a shared socio-economic pathways (SSPs) and RCPs. Our Water And Climate Adaptation Model (WatCAM) was used to compute the water gap based on reservoir capacity, water supply, and water demand. WatCam is based on the existing ModSim (Labadie, 2010) water allocation model, and facilitated the evaluation of nine technological and infrastructural adaptation measures to assess the investments needed to bridge the future water gap. Regional environmental and socio-economic effects of these investments, such as environmental flows or downstream effects, were evaluated. A scheme was developed to evaluate the strategies on robustness and flexibility under climate change and scenario uncertainty, and each measure was linked to possibilities for investment and financing mechanisms. The WatCAM is available as a web modeling service from www.water2invest.com, and enables user specified adaptation measures and the creation of an ensemble of water gap forecasts.

  20. 27. Detail view of mechanical float gages used to monitor ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. Detail view of mechanical float gages used to monitor level of water in the filtration bed reservoir. Gage on left measures water head, gage on right monitors filtration rate. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

  1. History of high-velocity impact water trauma at Letterman Army Medical Center: a 54-year experience with the Golden Gate Bridge.

    PubMed

    Lafave, M; LaPorta, A J; Hutton, J; Mallory, P L

    1995-04-01

    Three time frames were studied during the 54-year history of the Golden Gate Bridge from 1937 to 1991. During that period of time, there were 918 documented jumps from this majestic structure to the water 250 feet below. The last 15 years provided us with 297 consecutive patients, all brought to one institution, which were retrospectively reviewed and categorized as to site and type of injury for survivors and fatalities. This is the largest high-velocity water impact trauma series in the world. Certain unique characteristics of the Golden Gate Bridge and the San Francisco Bay lend itself to this extremely popular and successful form of suicide. These characteristics, as well as personal factors of free-fall water impact from each patient, are summarized and discussed in this paper.

  2. Transport of dissolved and suspended material by the Potomac River at Chain Bridge, at Washington, D.C., water years 1978-81

    USGS Publications Warehouse

    Blanchard, Stephen F.; Hahl, D.C.

    1987-01-01

    The measuring station Potomac River at Chain Bridge at Washington, D.C., is located at the upstream end of the tidal Potomac River. Water-quality data were collected intensively at this site from December 1977 through September 1981 as part of a study of the tidal Potomac River and Estuary. Analysis of water-discharge data from the long-term gage at Little Falls, just up stream from Chain Bridge, shows that streamflow for the 1979-81 water years had characteristics similar to the 51-year average discharge (1931-81). Loads were computed for various forms of phosphorus and nitrogen, major cations and anions, silica, biochemical oxygen demand, chlorophyll a and pheophytin, and suspended sediment. Load duration curves for the 1979-81 water years show that 50 percent of the time, water passing Chain Bridge carried at least 28 metric tons per day of total nitrogen, 1.0 metric tons per day of total phosphorus, 70 metric tons per day of silica, and 270 metric tons per day of suspended sediment. No consistent seasonal change in constituent concentrations was observed; however, a seasonal trend in loads due to seasonal changes in runoff was noted. Some storm runoff events transported as much dissolved and suspended material as is transported during an entire low-flow year.

  3. Hydrology-Vegetation Interactions Under Climate and Population Pressures: Bridging Ecology, Turbulence, and Water Resources (Invited)

    NASA Astrophysics Data System (ADS)

    Albertson, J. D.; Montaldo, N.

    2009-12-01

    Many of the contemporary research questions in the environmental sciences and engineering involve ever-increasing spatial and temporal scales, and intertwined features of the physical and biological sciences. One of the most clear examples of this is found in the connection between hydrology and meteorology, where plants control the energy and water exchange processes that impact so strongly the available water resources and climate. Ultimately, these fast processes (e.g. transpiration and photosynthesis), when integrated through time, manifest themselves as changes in the vegetation structure that then induce feedbacks on the land-atmosphere fluxes over longer time scales. In this talk we will look at the broad issue of how climate and land use changes impact water resources in semi-arid regions, including examples from sub-Saharan Africa and the Mediterranean. We examine some new tools and research results related to 1) modeling the dynamics of vegetation over long time scales, and 2) how the vegetation structure controls the turbulent transport phenomena connecting hydrology and meteorology.

  4. The UN Convention on International Watercourses and integrated water management: A bridge built

    NASA Astrophysics Data System (ADS)

    Tzatzaki, Vasiliki-Maria

    2008-11-01

    The UN Convention on the Law of the Non Navigational Uses of International Watercourses incorporates principles regarding the management of international water resources. The most important principles are the duty of the riparian states to cooperate, not to cause significant harm, to protect the aquatic environment and to utilize the watercourses reasonably and equitably. The lack of hierarchy between these principles signifies that the necessary step for the sound management of shared natural resources is an integrated approach, which takes into account economic development, human needs and environmental protection. Moreover, the UN Convention proved to be useful for the International Court of Justice (hereinafter ICJ) in the settlement of the Gabcikovo- Nagymaros dispute between Hungary and Slovakia for the Danube River. The Court highlighted the importance of the Convention by reminding the riparian states of their obligation to abide by its principles. On the other hand, the ICJ has used the principles of the Convention in the pending case of Pulp Mills between Uruguay and Argentina. This paper is going to show that the UN Convention is an international legal framework with general guidelines in order to create regional conventions, which promotes integrated water management as a solution to the emerging challenges of international water law and potential future conflicts.

  5. Mass accommodation of water: bridging the gap between molecular dynamics simulations and kinetic condensation models.

    PubMed

    Julin, Jan; Shiraiwa, Manabu; Miles, Rachael E H; Reid, Jonathan P; Pöschl, Ulrich; Riipinen, Ilona

    2013-01-17

    The condensational growth of submicrometer aerosol particles to climate relevant sizes is sensitive to their ability to accommodate vapor molecules, which is described by the mass accommodation coefficient. However, the underlying processes are not yet fully understood. We have simulated the mass accommodation and evaporation processes of water using molecular dynamics, and the results are compared to the condensation equations derived from the kinetic gas theory to shed light on the compatibility of the two. Molecular dynamics simulations were performed for a planar TIP4P-Ew water surface at four temperatures in the range 268-300 K as well as two droplets, with radii of 1.92 and 4.14 nm at T = 273.15 K. The evaporation flux from molecular dynamics was found to be in good qualitative agreement with that predicted by the simple kinetic condensation equations. Water droplet growth was also modeled with the kinetic multilayer model KM-GAP of Shiraiwa et al. [Atmos. Chem. Phys. 2012, 12, 2777]. It was found that, due to the fast transport across the interface, the growth of a pure water droplet is controlled by gas phase diffusion. These facts indicate that the simple kinetic treatment is sufficient in describing pure water condensation and evaporation. The droplet size was found to have minimal effect on the value of the mass accommodation coefficient. The mass accommodation coefficient was found to be unity (within 0.004) for all studied surfaces, which is in agreement with previous simulation work. Additionally, the simulated evaporation fluxes imply that the evaporation coefficient is also unity. Comparing the evaporation rates of the mass accommodation and evaporation simulations indicated that the high collision flux, corresponding to high supersaturation, present in typical molecular dynamics mass accommodation simulations can under certain conditions lead to an increase in the evaporation rate. Consequently, in such situations the mass accommodation coefficient

  6. Mass Accommodation of Water: Bridging the Gap Between Molecular Dynamics Simulations and Kinetic Condensation Models

    PubMed Central

    2012-01-01

    The condensational growth of submicrometer aerosol particles to climate relevant sizes is sensitive to their ability to accommodate vapor molecules, which is described by the mass accommodation coefficient. However, the underlying processes are not yet fully understood. We have simulated the mass accommodation and evaporation processes of water using molecular dynamics, and the results are compared to the condensation equations derived from the kinetic gas theory to shed light on the compatibility of the two. Molecular dynamics simulations were performed for a planar TIP4P-Ew water surface at four temperatures in the range 268–300 K as well as two droplets, with radii of 1.92 and 4.14 nm at T = 273.15 K. The evaporation flux from molecular dynamics was found to be in good qualitative agreement with that predicted by the simple kinetic condensation equations. Water droplet growth was also modeled with the kinetic multilayer model KM-GAP of Shiraiwa et al. [Atmos. Chem. Phys.2012, 117, 2777]. It was found that, due to the fast transport across the interface, the growth of a pure water droplet is controlled by gas phase diffusion. These facts indicate that the simple kinetic treatment is sufficient in describing pure water condensation and evaporation. The droplet size was found to have minimal effect on the value of the mass accommodation coefficient. The mass accommodation coefficient was found to be unity (within 0.004) for all studied surfaces, which is in agreement with previous simulation work. Additionally, the simulated evaporation fluxes imply that the evaporation coefficient is also unity. Comparing the evaporation rates of the mass accommodation and evaporation simulations indicated that the high collision flux, corresponding to high supersaturation, present in typical molecular dynamics mass accommodation simulations can under certain conditions lead to an increase in the evaporation rate. Consequently, in such situations the mass accommodation

  7. Bridging Mediterranean cultures in the IYS: A documentary exhibition on irrigation techniques in water scarcity conditions

    NASA Astrophysics Data System (ADS)

    Barontini, Stefano; Louki, Amina; Ben Slima, Zied; Ezzahra Ghaouch, Fatima; Labaran, Raisa; Raffelli, Giulia; Peli, Marco; Vitale, Nicola

    2015-04-01

    Brescia, an industrial city in Northern Italy, is now experiencing a crucial change in its traditional structure. In recent years in fact it has been elected as living and working seat by many foreigners and it is now one of the cities with the greatest percentage of migrants in the Country. This is an important challenge for the city and an opportunity to merge, compare and integrate different cultures to build its future. In this context some students of different Courses (engineering and medicine), belonging both to the Arabian and local community, met together and with researchers in the study team 'Al-B¯i r¯u n¯i , for culture, science and society'. The team aims at organising cultural events in which, starting from the figure of the Persian scientist Ab¯u Raih. ¯a n Al-B¯i r¯u n¯i (about 973, 1051), the contribution of the Arabian and Islamic culture to the development of the European one in the middle ages is investigated. Moving from the initial idea of the study team Al-B¯i r¯u n¯i and from the suggestions of the World Soil Day 2014 and of the International Year of Soils 2015, we built a documentary exhibition entitled 'Irrigation techniques in water scarcity conditions'. The exhibition, which stresses the importance of the irrigation techniques for the soil conservation, is focused on the idea of disseminating two main concepts, i.e. (1) the technological continuity of some water supply systems in countries, around the Mediterranean Sea, affected by similar conditions of water availability, and (2) the possibility of building environments where, due to severe or extreme climatic conditions, the sustainability is reached when the man lives in equilibrium with the nature. The exhibition, which is written in Italian and will move around in the city during all 2015, consists of about twenty posters organized into three main chapters, corresponding to three main classes of water supply systems which are common in most of the countries surrounding

  8. Floating-diffusion electrometer with adjustable sensitivity

    NASA Technical Reports Server (NTRS)

    Tower, John R. (Inventor)

    1989-01-01

    The effective capacitance of the floating diffusion in a floating-diffusion electrometer is modified to adjust electrometer sensitivity. This is done by changing the direct potential applied to a gate electrode proximate to the floating diffusion.

  9. Salinity and temperature in South San Francisco Bay, California, at Dumbarton Bridge: results from the 1999-2002 water years and an overview of previous data

    USGS Publications Warehouse

    Schemel, Laurence E.; Brown, Randall L.; Bell, Norton W.

    2003-01-01

    Salinity and temperature were measured in near-surface waters at Dumbarton Bridge in South San Francisco Bay during the 1999?2002 water years (1999WY?2002WY). The complete data set from this site, which included 1990WY?1993WY and 1995WY?1998WY, provided a time?series of observations covering a wide range of hydrologic conditions. These conditions included critically dry years and years with above-normal and near?record precipitation and discharges from the major rivers and local streams. Data collection at 15?minute intervals allowed resolution of variability associated with daily tides and other short-term phenomena. Both local stream discharges to South San Francisco Bay and Sacramento?San Joaquin River discharges to North San Francisco Bay affected salinity at Dumbarton Bridge. Salinity at Dumbarton Bridge varied with the daily tides, and the lowest salinity values (annual) coincided with precipitation and freshwater inflows usually in winter. Short?term and seasonal variations in temperature at Dumbarton Bridge typically followed changes in air temperature and solar irradiance.

  10. Underwater and Floating-Leaved Plants of the United States and Canada.

    ERIC Educational Resources Information Center

    Hotchkiss, Neil

    This is the third in a series of guides to the field identification of North American marsh and water plants. Described are plants which have foliage habitually under water or floating, or which have underwater or floating forms, and which have characteristics by which they can be distinguished with the naked eye. Where genera or species cannot be…

  11. Bridging Troubled Waters: Historians, Natural Resource Litigation, and the Expert Witness Phenomenon.

    PubMed

    Brescia, Michael M

    2015-02-01

    This special issue of The Public Historian examines the nature and scope of the historian's role as a consultant and expert witness in natural resource litigation. The introductory essay identifies the major issues and challenges that historians face when they bring their knowledge, skills, and professional best standards into law offices and courtrooms, while also positing a conceptual framework for public history practitioners to better understand and appreciate the larger stakes in conducting research for environmental litigation. The author delineates his own experience as an expert in certain water rights cases in the American Southwest where knowledge of the Spanish and Mexican civil law of property is essential.

  12. Nonspecific base recognition mediated by water bridges and hydrophobic stacking in ribonuclease I from Escherichia coli

    PubMed Central

    Rodriguez, Sergio Martinez; Panjikar, Santosh; Van Belle, Karolien; Wyns, Lode; Messens, Joris; Loris, Remy

    2008-01-01

    The crystal structure of Escherichia coli ribonuclease I (EcRNase I) reveals an RNase T2-type fold consisting of a conserved core of six β-strands and three α-helices. The overall architecture of the catalytic residues is very similar to the plant and fungal RNase T2 family members, but the perimeter surrounding the active site is characterized by structural elements specific for E. coli. In the structure of EcRNase I in complex with a substrate-mimicking decadeoxynucleotide d(CGCGATCGCG), we observe a cytosine bound in the B2 base binding site and mixed binding of thymine and guanine in the B1 base binding site. The active site residues His55, His133, and Glu129 interact with the phosphodiester linkage only through a set of water molecules. Residues forming the B2 base recognition site are well conserved among bacterial homologs and may generate limited base specificity. On the other hand, the B1 binding cleft acquires true base aspecificity by combining hydrophobic van der Waals contacts at its sides with a water-mediated hydrogen-bonding network at the bottom. This B1 base recognition site is highly variable among bacterial sequences and the observed interactions are unique to EcRNaseI and a few close relatives. PMID:18305191

  13. Computational study of phosphatase activity in soluble epoxide hydrolase: high efficiency through a water bridge mediated proton shuttle.

    PubMed

    De Vivo, Marco; Ensing, Bernd; Klein, Michael L

    2005-08-17

    Recently, a new branch of fatty acid metabolism has been opened by the novel phosphatase activity found in the N-terminal domain of the, hence bifunctional, soluble epoxide hydrolase (sEH). Importantly, this finding has also provided a new site for drug targeting in sEH's activity regulation. Classical MD and hybrid Car-Parrinello QM/MM calculations have been performed to investigate the reaction mechanism of the phosphoenzyme intermediate formation in the first step of the catalysis. The results support a concerted multi-event reaction mechanism: (1) a dissociative in-line nucleophilic substitution for the phosphoryl transfer reaction; (2) a double proton transfer involved in the formation of a good leaving group in the transition state. The presence of a water bridge in the substrate/enzyme complex allowed an efficient proton shuttle, showing its key role in speeding up the catalysis. The calculated free energy of the favored catalytic pathway is approximately 19 kcal/mol, in excellent agreement with experimental data.

  14. Nanometer-Sized Water Bridge and Pull-Off Force in AFM at Different Relative Humidities: Reproducibility Measurement and Model Based on Surface Tension Change.

    PubMed

    Bartošík, Miroslav; Kormoš, Lukáš; Flajšman, Lukáš; Kalousek, Radek; Mach, Jindřich; Lišková, Zuzana; Nezval, David; Švarc, Vojtěch; Šamořil, Tomáš; Šikola, Tomáš

    2017-01-26

    This article deals with the analysis of the relationship between the pull-off force measured by atomic force microscopy and the dimensions of water bridge condensed between a hydrophilic silicon oxide tip and a silicon oxide surface under ambient conditions. Our experiments have shown that the pull-off force increases linearly with the radius of the tip and nonmonotonically with the relative humidity (RH). The latter dependence generally consists of an initial constant part changing to a convex-concave-like increase of the pull-off force and finally followed by a concave-like decrease of this force. The reproducibility tests have demonstrated that the precision limits have to be taken into account for comparing these measurements carried out under atmospheric conditions. The results were fitted by a classical thermodynamic model based on water-bridge envelope calculations using the numerical solution of the Kelvin equation in the form of axisymmetric differential equations and consequent calculation of adhesive forces. To describe the measured data more precisely, a decrease of the water surface tension for low RH was incorporated into the calculation. Such a decrease can be expected as a consequence of the high surface curvature in the nanometer-sized water bridge between the tip and the surface.

  15. Does It Sink or Float?

    ERIC Educational Resources Information Center

    McDonald, Judith Richards

    2012-01-01

    This activity is designed to teach prekindergarten to second grade students about the concept of sink or float through an inquiry activity. Students will use familiar objects to predict and test the properties of sink and float. Background information is offered to teachers to assist them with this activity. This lesson begins with an engaging…

  16. BEST POSSIBLE FLOATING POINT ARITHMETIC.

    DTIC Science & Technology

    The report presents an algorithm for floating point arithmetic, using single-length arithmetic registers, which yields the most accurate...approximation which can be expressed in the given floating point format, the greatest lower bound, or the least upper bound for the result of the operation

  17. Does It Sink or Float?

    ERIC Educational Resources Information Center

    McDonald, Judith Richards

    2012-01-01

    This activity is designed to teach prekindergarten to second grade students about the concept of sink or float through an inquiry activity. Students will use familiar objects to predict and test the properties of sink and float. Background information is offered to teachers to assist them with this activity. This lesson begins with an engaging…

  18. Inexpensive, floating, insect-emergence trap

    SciTech Connect

    Cushman, R.M.

    1983-11-01

    The Environmental Sciences Division of Oak Ridge National Laboratory has been investigating the usefulness of aquarium microcosms and ponds for the quantification and predictions of toxicant effects on freshwater systems. Ideally, concepts and methods applicable to both 150-L microcosms and 15,000-L ponds would bridge the gap between the two. The effort of processing the benthic samples, as well as the destructiveness of the sampling in small ponds, limited the number of samples that could be taken. Therefore, the author developed an inexpensive emergence trap appropriate for use in small outdoor ponds, as one method of increasing sampling efficiency and economy. To prevent the possibility of trapping adults from adjacent ponds, which would confound the results, the traps had to be designed such that they could only trap insects from the ponds upon which they were floating. The design of this trap is described.

  19. Instantaneous stabilization of floating oils by surface application of natural granular materials (beach sand and limestone).

    PubMed

    Boglaienko, Daria; Tansel, Berrin

    2015-02-15

    When granular materials are applied to hydrophobic liquids floating over another liquid (i.e., water), particles form aggregates which can be separated from the floating phase. This concept can be used for controlling mobility of floating oils, especially after oil spills near coastal areas. The objectives of this research were to characterize oil capture efficiency and determine effectiveness of particles for converting the floating phase to a heavier phase for effective separation. Experiments were conducted with South Louisiana crude oil contaminated salt water, limestone and quartz sand. Although the oil removal efficiency increased with the increasing amount of granular material applied, it did not increase linearly. About 50% of the floating oil was removed by aggregates, regardless of the material used, when granular material to floating oil ratio was about 1 g/g. The aggregates separated had higher amounts of oil content when smaller amounts of granular materials were added. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Comparison of two microextraction methods based on solidification of floating organic droplet for the determination of multiclass analytes in river water samples by liquid chromatography tandem mass spectrometry using Central Composite Design.

    PubMed

    Asati, Ankita; Satyanarayana, G N V; Patel, Devendra K

    2017-09-01

    Two low density organic solvents based liquid-liquid microextraction methods, namely Vortex assisted liquid-liquid microextraction based on solidification of floating organic droplet (VALLME-SFO) and Dispersive liquid-liquid microextraction based on solidification of floating organic droplet(DLLME-SFO) have been compared for the determination of multiclass analytes (pesticides, plasticizers, pharmaceuticals and personal care products) in river water samples by using liquid chromatography tandem mass spectrometry (LC-MS/MS). The effect of various experimental parameters on the efficiency of the two methods and their optimum values were studied with the aid of Central Composite Design (CCD) and Response Surface Methodology(RSM). Under optimal conditions, VALLME-SFO was validated in terms of limit of detection, limit of quantification, dynamic linearity range, determination of coefficient, enrichment factor and extraction recovery for which the respective values were (0.011-0.219ngmL(-1)), (0.035-0.723ngmL(-1)), (0.050-0.500ngmL(-1)), (R(2)=0.992-0.999), (40-56), (80-106%). However, when the DLLME-SFO method was validated under optimal conditions, the range of values of limit of detection, limit of quantification, dynamic linearity range, determination of coefficient, enrichment factor and extraction recovery were (0.025-0.377ngmL(-1)), (0.083-1.256ngmL(-1)), (0.100-1.000ngmL(-1)), (R(2)=0.990-0.999), (35-49), (69-98%) respectively. Interday and intraday precisions were calculated as percent relative standard deviation (%RSD) and the values were ≤15% for VALLME-SFO and DLLME-SFO methods. Both methods were successfully applied for determining multiclass analytes in river water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Floating behavior of hydrophobic glass spheres.

    PubMed

    Liu, Xinjie; Wang, Xiaolong; Liang, Yongmin; Zhou, Feng

    2009-08-15

    When a hydrophobic solid sphere is floating on water or salt solutions with different concentrations, it is at equilibrium under the impact of gravity, buoyancy force, and curvature force, the component of surface tension in the vertical direction. We have changed the diameters of the spheres and the concentrations of the two selected salts, NaCl and NaNO(3), to study the floating behaviors of these spheres and the contributions of surface tension and buoyancy force to their floatation. Generally speaking, the surface tension plays a more important role than the buoyancy force when the gravity is small, but the buoyancy force plays an identical or a more important role when the spheres are big enough. The wettability of the spheres significantly influences the height below the contact perimeter especially in salt solutions. The theoretical calculation meniscus slope angles at the sphere three-phase contact line are in agreement with experimental results.

  2. Capillary deposition of advected floating particles

    NASA Astrophysics Data System (ADS)

    Dressaire, Emilie; Debaisieux, Aymeric; Gregori, Federico

    2016-11-01

    The deposition and aggregation of particles flowing through a confined environment can dramatically hinder the transport of suspensions. Yet, the mechanisms responsible for the deposition of particles in shear flow are not fully understood. Here, we use an experimental model system in which floating particles are advected on the surface of a water channel and deposited on fixed obstacles through attractive capillary effects. By varying the flow rate of the liquid, the wetting properties and size of the particles and obstacles, we can tune the magnitude of the capillary and hydrodynamic forces that determine the probability of deposition and the equilibrium position on the substrate. We show that arrays of obstacles can be designed to efficiently capture the floating particles advected by the flow.

  3. Bridging the Gaps.

    ERIC Educational Resources Information Center

    Netzer, Greg

    1995-01-01

    Discusses a model water quality monitoring project, Project Bridge, established to train minority girls about to enter eighth grade in scientific procedures followed by hands-on experimentation. Students spent a week monitoring water in an urban stream and analyzing results. (LZ)

  4. Tidal Energy Conversion Installation at an Estuarine Bridge Site: Resource Evaluation and Energy Production Estimate

    NASA Astrophysics Data System (ADS)

    Wosnik, M.; Gagnon, I.; Baldwin, K.; Bell, E.

    2015-12-01

    The "Living Bridge" project aims to create a self-diagnosing, self-reporting "smart bridge" powered by a local renewable energy source, tidal energy - transforming Memorial Bridge, a vertical lift bridge over the tidal Piscataqua River connecting Portsmouth, NH and Kittery, ME, into a living laboratory for researchers, engineers, scientists, and the community. The Living Bridge project includes the installation of a tidal turbine at the Memorial Bridge. The energy converted by the turbine will power structural health monitoring, environmental and underwater instrumentation. Utilizing locally available tidal energy can make bridge operation more sustainable, can "harden" transportation infrastructure against prolonged grid outages and can demonstrate a prototype of an "estuarine bridge of the future". A spatio-temporal tidal energy resource assessment was performed using long term bottom-deployed Acoustic Doppler Current Profilers (ADCP) at two locations: near the planned deployment location in 2013-14 for 123 days and mid-channel in 2007 for 35 days. Data were evaluated to determine the amount of available kinetic energy that can be converted into usable electrical energy on the bridge. Changes in available kinetic energy with ebb/flood and spring/neap tidal cycles and electrical energy demand were analyzed. The target deployment site exhibited significantly more energetic ebb tides than flood tides, which can be explained by the local bathymetry of the tidal estuary. A system model is used to calculate the net energy savings using various tidal generator and battery bank configurations. Different resource evaluation methodologies were also analyzed, e.g., using a representative ADCP "bin" vs. a more refined, turbine-geometry-specific methodology, and using static bin height vs. bin height that move w.r.t. the free surface throughout a tidal cycle (representative of a bottom-fixed or floating turbine deployment, respectively). ADCP operating frequencies and bin

  5. Bridge over troubled water: resolving the competing photosystem II crystal structures.

    PubMed

    Petrie, Simon; Stranger, Rob; Gatt, Phillip; Pace, Ron J

    2007-01-01

    Density functional theory (DFT) calculations, at the Becke-Perdew/TZP level of theory, were used to investigate a set of CaMn(4)-containing clusters that model the active site of the water-oxidizing complex (WOC) of photosystem II (PSII). Metal-atom positions for three representative isomeric clusters of the formula [CaMn(4)C(9)N(2)O(16)H(10)](+)4 H(2)O are in good agreement with the disparate Mn(4) geometries of the three most recent X-ray crystal structures. Remarkably, interconversion between these three isomeric clusters is found to be facile, resulting from subtle changes in the coordination environment around the CaMn(4) centre. This result provides a clear rationalisation of the marked differences in reported crystal structures. Recent concerns have been raised regarding the opportunity for X-ray-damage-induced distortion of the metal-containing active centre during crystallographic analysis. Our calculations suggest that an even greater problem may be presented by the apparent fluxionality of the CaMn(4) skeleton within the active centre. Structural rearrangement may well precede crystallographic analysis, for example by the preferential "freezing-out" of one of several near-isoenergetic structures during the workup for crystallisation. This prospect, which our calculations cannot exclude, highlights the difficulties that will continue to be faced by experimentalists seeking unambiguous structural information on the WOC's active site.

  6. Influence of different types of low substituted hydroxypropyl cellulose on tableting, disintegration, and floating behaviour of floating drug delivery systems

    PubMed Central

    Diós, Péter; Pernecker, Tivadar; Nagy, Sándor; Pál, Szilárd; Dévay, Attila

    2014-01-01

    The object of the present study is to evaluate the effect of application of low-substituted hydroxypropyl cellulose (L-HPC) 11 and B1 as excipients promoting floating in gastroretentive tablets. Directly compressed tablets were formed based on experimental design. Face-centred central composite design was applied with two factors and 3 levels, where amount of sodium alginate (X1) and L-HPC (X2) were the numerical factors. Applied types of L-HPCs and their 1:1 mixture were included in a categorical factor (X3). Studied parameters were floating lag time, floating time, floating force, swelling behaviour of tablets and dissolution of paracetamol, which was used as a model active substance. Due to their physical character, L-HPCs had different water uptake and flowability. Lower flowability and lower water uptake was observed after 60 min at L-HPC 11 compared to L-HPC B1. Shorter floating times were detected at L-HPC 11 and L-HPC mixtures with 0.5% content of sodium alginate, whereas alginate was the only significant factor. Evaluating results of drug release and swelling studies on floating tablets revealed correlation, which can serve to help to understand the mechanism of action of L-HPCs in the field development of gastroretentive dosage forms. PMID:26702261

  7. Influence of different types of low substituted hydroxypropyl cellulose on tableting, disintegration, and floating behaviour of floating drug delivery systems.

    PubMed

    Diós, Péter; Pernecker, Tivadar; Nagy, Sándor; Pál, Szilárd; Dévay, Attila

    2015-11-01

    The object of the present study is to evaluate the effect of application of low-substituted hydroxypropyl cellulose (L-HPC) 11 and B1 as excipients promoting floating in gastroretentive tablets. Directly compressed tablets were formed based on experimental design. Face-centred central composite design was applied with two factors and 3 levels, where amount of sodium alginate (X 1) and L-HPC (X2 ) were the numerical factors. Applied types of L-HPCs and their 1:1 mixture were included in a categorical factor (X 3). Studied parameters were floating lag time, floating time, floating force, swelling behaviour of tablets and dissolution of paracetamol, which was used as a model active substance. Due to their physical character, L-HPCs had different water uptake and flowability. Lower flowability and lower water uptake was observed after 60 min at L-HPC 11 compared to L-HPC B1. Shorter floating times were detected at L-HPC 11 and L-HPC mixtures with 0.5% content of sodium alginate, whereas alginate was the only significant factor. Evaluating results of drug release and swelling studies on floating tablets revealed correlation, which can serve to help to understand the mechanism of action of L-HPCs in the field development of gastroretentive dosage forms.

  8. Behavior of Flotsam in the California Current System Utilizing Surface Drift of RAFOS Floats

    DTIC Science & Technology

    2012-09-01

    illustrates approximate water level when floating on the ocean surface. Float is constructed from a 0.08 m by 1.52 m glass tube...such as the “ Great Pacific Garbage Patch” (Howell et al. 2012) or possibly washed ashore (Maximenko et al. 2012). Flotsam drifts in the surface...is constructed from a 0.08 m by 1.52 m glass tube, which houses the electronics required for operation. 4 Figure 1. RAFOS Float (Woods Hole

  9. Determination of the steroid hormone levels in water samples by dispersive liquid-liquid microextraction with solidification of a floating organic drop followed by high-performance liquid chromatography.

    PubMed

    Chang, Chu-Chi; Huang, Shang-Da

    2010-03-03

    In this study, the steroid hormone levels in river and tap water samples were determined by using a novel dispersive liquid-liquid microextraction method based on the solidification of a floating organic drop (DLLME-SFO). Several parameters were optimized, including the type and volume of the extraction and dispersive solvents, extraction time, and salt effect. DLLME-SFO is a fast, cheap, and easy-to-use method for detecting trace levels of samples. Most importantly, this method uses less-toxic solvent. The correlation coefficient of the calibration curve was higher than 0.9991. The linear range was from 5 to 1000 microg L(-1). The spiked environmental water samples were analyzed using DLLME-SFO. The relative recoveries ranged from 87% to 116% for river water (which was spiked with 4 microg L(-1) for E1, 3 microg L(-1) for E2, 4 microg L(-1) for EE2 and 9 microg L(-1) for E3) and 89% to 102% for tap water (which was spiked with 6 microg L(-1) for E1, 5 microg L(-1) for E2, 6 microg L(-1) for EE2 and 10 microg L(-1) for E3). The detection limits of the method ranged from 0.8 to 2.7 microg L(-1) for spiked river water and 1.4 to 3.1 microg L(-1) for spiked tap water. The methods precision ranged from 8% to 14% for spiked river water and 7% to 14% for spiked tap water.

  10. Clear-Water Contraction Scour at Selected Bridge Sites in the Black Prairie Belt of the Coastal Plain in Alabama, 2006

    USGS Publications Warehouse

    Lee, K.G.; Hedgecock, T.S.

    2008-01-01

    The U.S. Geological Survey, in cooperation with the Alabama Department of Transportation, made observations of clear-water contraction scour at 25 bridge sites in the Black Prairie Belt of the Coastal Plain of Alabama. These bridge sites consisted of 54 hydraulic structures, of which 37 have measurable scour holes. Observed scour depths ranged from 1.4 to 10.4 feet. Theoretical clear-water contraction-scour depths were computed for each bridge and compared with observed scour. This comparison showed that theoretical scour depths, in general, exceeded the observed scour depths by about 475 percent. Variables determined to be important in developing scour in laboratory studies along with several other hydraulic variables were investigated to understand their influence within the Alabama field data. The strongest explanatory variables for clear-water contraction scour were channel-contraction ratio and velocity index. Envelope curves were developed relating both of these explanatory variables to observed scour. These envelope curves provide useful tools for assessing reasonable ranges of scour depth in the Black Prairie Belt of Alabama.

  11. Photochemical and thermal hydrogen production from water catalyzed by carboxylate-bridged dirhodium(II) complexes.

    PubMed

    Tanaka, Saya; Masaoka, Shigeyuki; Yamauchi, Kosei; Annaka, Masahiko; Sakai, Ken

    2010-12-14

    A series of dinuclear Rh(II) complexes, [Rh(2)(μ-OAc)(4)(H(2)O)(2)] (HOAc = acetic acid) (1), [Rh(2)(μ-gly)(4)(H(2)O)(2)] (Hgly = glycolic acid) (2), [Rh(2)(μ-CF(3)CO(2))(4)(acetone)(2)] (3), and [Rh(2)(bpy)(2)(μ-OAc)(2)(OAc)(2)] (4), were found to serve as H(2)-evolving catalysts in a three-component system consisting of tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)(3)(2+)), methylviologen (MV(2+)), and ethylenediaminetetraacetic acid disodium salt (EDTA). It was also confirmed that thermal reduction of water into H(2) by MV(+)˙, in situ generated by the bulk electrolysis of MV(2+), is effectively promoted by 1 as a H(2)-evolving catalyst. The absorption spectra of the photolysis solution during the photocatalysis were monitored up to 6 h to reveal that the formation of photochemical or thermal byproducts of MV(+)˙ is dramatically retarded in the presence of the Rh(II)(2) catalysts, for the H(2) formation rather than the decomposition of MV(+)˙ becomes predominant in the presence of the Rh(II)(2) catalysts. The stability of the Rh(II)(2) dimers was confirmed by absorption spectroscopy, (1)H NMR, and ESI-TOF mass spectroscopy. The results indicated that neither elimination nor replacement of the equatorial ligands take place during the photolysis, revealing that one of the axial sites of the Rh(2) core is responsible for the hydrogenic activation. The quenching of Ru*(bpy)(3)(2+) by 1 was also investigated by luminescence spectroscopy. The rate of H(2) evolution was found to decrease upon increasing the concentration of 1, indicating that the quenching of Ru*(bpy)(3)(2+) by the Rh(ii)(2) species rather than by MV(2+) becomes predominant at the higher concentrations of 1. The DFT calculations were carried out for several possible reaction paths proposed (e.g., [Rh(II)(2)(μ-OAc)(4)(H(2)O)] + H(+) and [Rh(II)(2)(μ-OAc)(4)(H(2)O)] + H(+) + e(-)). It is suggested that the initial step is a proton-coupled electron transfer (PCET) to the Rh(II)(2) dimer leading to

  12. Floating Silicon Method

    SciTech Connect

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

  13. Floating into Deep Space

    NASA Astrophysics Data System (ADS)

    La Frenais, R.; Saraceno, T.; Powell, J.

    2014-04-01

    Is it possible for spaceflight to become more sustainable? Artist and architect Tomas Saraceno proposes a long-term artscience research project based on his initial work with solar balloons to join with the efforts of engineers such as John Powell, working on the Airship to Orbit experiments, which describe a three stage process of using airships to fly to a large suborbital "Dark Sky Station' then literally floating into orbit with additional electrical and chemical propulsion. (See: http://www.jpaerospace.com) In his artworks Tomás Saraceno proposes cell-like flying cities as possible architectonic living spaces in direct reference to Buckminster Fuller's Cloud Nine (circa 1960). The fantastic architectural utopia Cloud Nine consists of a freely floating sphere measuring one mile in diameter that offers living space to several autonomous communities encompassing thousands of inhabitants each. The notion of the cloud is essential to the artist's work. The cloud as metaphor stands for artistic intention, for the meaning of territory and border in today's (urban) society, and for exploring possibilities for the sustainable development of the human living environment. In Saraceno's work this environment is not limited to the earth, but is explicitly conceived to reach into outer space. (Biomimetic Constructions- On the works of Tomás Saraceno By Katharina Schlüter) Saraceno is also interested in human factors experiments using his existing constructions as analogue environments for living on Mars and is proposing carry out a series of workshops, experiments and solar balloon launces in White Sands desert in early 2016 in collaboration with the curator Dr Rob La Frenais, the Rubin Center at The University of Texas at El Paso and various scientific partners.

  14. 33 CFR 144.01-10 - Equipment for life floats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Equipment for life floats. 144.01-10 Section 144.01-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES LIFESAVING APPLIANCES Manned Platforms § 144.01-10...

  15. Bio-Conjugated CNT-Bridged 3D Porous Graphene Oxide Membrane for Highly Efficient Disinfection of Pathogenic Bacteria and Removal of Toxic Metals from Water.

    PubMed

    Nellore, Bhanu Priya Viraka; Kanchanapally, Rajashekhar; Pedraza, Francisco; Sinha, Sudarson Sekhar; Pramanik, Avijit; Hamme, Ashton T; Arslan, Zikri; Sardar, Dhiraj; Ray, Paresh Chandra

    2015-09-02

    More than a billion people lack access to safe drinking water that is free from pathogenic bacteria and toxic metals. The World Health Organization estimates several million people, mostly children, die every year due to the lack of good quality water. Driven by this need, we report the development of PGLa antimicrobial peptide and glutathione conjugated carbon nanotube (CNT) bridged three-dimensional (3D) porous graphene oxide membrane, which can be used for highly efficient disinfection of Escherichia coli O157:H7 bacteria and removal of As(III), As(V), and Pb(II) from water. Reported results demonstrate that versatile membrane has the capability to capture and completely disinfect pathogenic pathogenic E. coli O157:H7 bacteria from water. Experimentally observed disinfection data indicate that the PGLa attached membrane can dramatically enhance the possibility of destroying pathogenic E. coli bacteria via synergistic mechanism. Reported results show that glutathione attached CNT-bridged 3D graphene oxide membrane can be used to remove As(III), As(V), and Pb(II) from water sample at 10 ppm level. Our data demonstrated that PGLa and glutathione attached membrane has the capability for high efficient removal of E. coli O157:H7 bacteria, As(III), As(V), and Pb(II) simultaneously from Mississippi River water.

  16. Bacillus anthracis GrlAV96A topoisomerase IV, a quinolone resistance mutation that does not affect the water-metal ion bridge.

    PubMed

    Aldred, Katie J; Breland, Erin J; McPherson, Sylvia A; Turnbough, Charles L; Kerns, Robert J; Osheroff, Neil

    2014-12-01

    The rise in quinolone resistance is threatening the clinical use of this important class of broad-spectrum antibacterials. Quinolones kill bacteria by increasing the level of DNA strand breaks generated by the type II topoisomerases gyrase and topoisomerase IV. Most commonly, resistance is caused by mutations in the serine and acidic amino acid residues that anchor a water-metal ion bridge that facilitates quinolone-enzyme interactions. Although other mutations in gyrase and topoisomerase IV have been reported in quinolone-resistant strains, little is known regarding their contributions to cellular quinolone resistance. To address this issue, we characterized the effects of the V96A mutation in the A subunit of Bacillus anthracis topoisomerase IV on quinolone activity. The results indicate that this mutation causes an ∼ 3-fold decrease in quinolone potency and reduces the stability of covalent topoisomerase IV-cleaved DNA complexes. However, based on metal ion usage, the V96A mutation does not disrupt the function of the water-metal ion bridge. A similar level of resistance to quinazolinediones (which do not use the bridge) was seen. V96A is the first topoisomerase IV mutation distal to the water-metal ion bridge demonstrated to decrease quinolone activity. It also represents the first A subunit mutation reported to cause resistance to quinazolinediones. This cross-resistance suggests that the V96A change has a global effect on the structure of the drug-binding pocket of topoisomerase IV. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  17. 33 CFR 118.85 - Lights on vertical lift bridges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

  18. 33 CFR 118.85 - Lights on vertical lift bridges.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

  19. 33 CFR 118.85 - Lights on vertical lift bridges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

  20. 33 CFR 118.85 - Lights on vertical lift bridges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

  1. 33 CFR 118.85 - Lights on vertical lift bridges.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

  2. 75 FR 75934 - Airworthiness Directives; Apical Industries Inc. (Apical) Emergency Float Kits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-07

    ... prompted by a report of a helicopter that crashed into the water, and the pilot did not deploy the floats... installed. This proposal is prompted by a report of a helicopter that crashed into the water, and the pilot...

  3. Floating gate circuits in MOSIS

    NASA Astrophysics Data System (ADS)

    Mann, James R.

    1990-11-01

    The MOSIS foundry offers a two-poly CMOS process that can be used as a floating gate technology, albeit not with the same performance as commercial EEPROM foundries. This report characterizes the structures and programming techniques necessary to build floating gate structures and associated high-voltage addressing circuitry on the low-noise analog process available through MOSIS. Techniques that are used include Fowler-Nordheim tunneling, channel hot-electron injection, and avalanche injection. The dielectric materials between the floating gate and both the control gate and substrate are characterized. Unconventional lightly doped drain FET devices and additional circuit techniques for handling the high-voltage programming signals are presented.

  4. Quantification of floating macroalgae blooms using the scaled algae index

    NASA Astrophysics Data System (ADS)

    Garcia, Rodrigo A.; Fearns, Peter; Keesing, John K.; Liu, Dongyan

    2013-01-01

    Quantifying the spatial coverage of floating macroalgae from satellite imagery, using methods such as the normalized difference vegetation index (NDVI) and the floating algae index (FAI), requires the use of a scene-wide threshold to isolate and then compute the number of floating macroalgae pixels. The problem faced is the sensitivity of the NDVI and, to a lesser extent, the FAI to radiance contributions from atmospheric aerosols and turbid water. Both these factors can vary significantly across a satellites' field-of-view generating irregular apparent reflectance of ocean and floating macroalgae pixels across an NDVI/FAI scene, leading to inaccuracies in spatial coverage estimates. We present a simple image processing algorithm, termed the scaled algae index (SAI), that removes any variability present in ocean and floating macroalgae pixels in NDVI or FAI imagery. The SAI does this by subtracting a given pixel's index by that of a local ocean pixel, effectively scaling ocean pixels to values near zero, and macroalgae pixels to positive values. The SAI algorithm has been tested on NDVI and FAI scenes of the 2008/2009 floating macroalgae blooms that occurred in the Yellow Sea, China. These SAI images show a major reduction in variability with scene-wide histograms being unimodal. Histogram analysis also indicates that sufficient contrast exists between ocean and floating macroalgae pixels to enable segmentation by a scene-wide threshold. A semiautomated threshold determination procedure is also presented, which together with the SAI algorithm can be used to compute accurate estimates of the spatial coverage of floating macroalgae.

  5. Ipsilateral Floating Hip and Floating Knee - A Rare Entity.

    PubMed

    Yashavantha Kumar, C; Nalini, K B; Nagaraj, Prashanth; Jawali, Abhijith

    2013-01-01

    Ipsilateral floating hip and floating knee are very rare injuries. These injuries so uncommon that only three cases of similar kind have been reported. These injuries are due to high velocity injuries following motor vehicle accidents. Management of such complex injuries is a challenging task even in experienced hands as there are no standard treatment guidelines for such fractures. We hereby report a 20 yr old male who sustained ipsilateral floating hip and ipsilateral floating knee injuries following motor vehicle accident. Patient was stabilized initially and later taken up for surgery. Patient was treated with interlocking nail for femur and tibia in the same sitting whereas acetabulam fracture was managed conservatively. At five months all the fractures united well with restoration of good range of motion in both hip and knee. Ipsilateral floating knee and floating hip are very rare injuries seen following high velocity motor vehicle accidents. There are no standard guidelines for treatment of those fractures as only a few cases of similar kind have been reported in literature. Early fixation and aggressive mobilization ensures fracture union and fewer complications.

  6. Safer Bridges

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Safer bridges are among a number of spinoff benefits from NASA procedures for testing 'cfracture toughness" of a structural part, meaning its ability to -siscracktsh at might cause failure. The New River Bridge in West Virginia, shown under construction, is the world's largest single span bridge. U.S. Steel fracture toughness requirements for such bridges include NASA-developed test procedures. Bridge materials and other metal structures may develop flaws during their service lifetimes. Such flaws can affect the structural integrity of the part. Thus, it is important to know the "fracture toughness" of a structural part, or its ability to resist cracks. NASA has long experience in developing fracture toughness tests for aerospace hardware. Since 1960, NASA-Lewis has worked closely with the American Society for Testing & Materials. Lewis and NASA-funded industrial contractors have made many important contributions to test procedures, now recommended by ASTM, for measuring fracture toughness.

  7. 33 CFR 115.50 - Application for bridge permits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... courts, the power to authorize the construction of bridges, they must furnish with their application... reference to the planes of mean high water and mean low water if the bridge is to cross tidal water. If the...

  8. 33 CFR 115.50 - Application for bridge permits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... courts, the power to authorize the construction of bridges, they must furnish with their application... reference to the planes of mean high water and mean low water if the bridge is to cross tidal water. If the...

  9. 33 CFR 115.50 - Application for bridge permits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... courts, the power to authorize the construction of bridges, they must furnish with their application... reference to the planes of mean high water and mean low water if the bridge is to cross tidal water. If the...

  10. 33 CFR 115.50 - Application for bridge permits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... courts, the power to authorize the construction of bridges, they must furnish with their application... reference to the planes of mean high water and mean low water if the bridge is to cross tidal water. If the...

  11. An insight to the dynamics of conserved water-mediated salt bridge interaction and interdomain recognition in hIMPDH isoforms.

    PubMed

    Bairagya, Hridoy R; Mukhopadhyay, Bishnu P

    2013-01-01

    Inosine monophosphate dehydrogenase (IMPDH) is involved in de novo biosynthesis pathway of guanosine nucleotide. Type II isoform of this enzyme is selectively upregulated in lymphocytes and chronic myelogenous leukemia (CML) cells, and is an excellent target for antileukemic agent. The molecular dynamics simulation results (15 ns) of three unliganded 1B3O, 1JCN, and 1JR1 structures have clearly revealed that IN, IC (N- and C-terminal of catalytic domains) and C1, C2 (cystathionine-beta-synthase-1 and 2) domains of IMPDH enzyme have been stabilized by six conserved water (center) mediated salt bridge interactions. These conserved water molecules could be involved in interdomain or intradomain recognition, intradomain coupling, and charge transfer processes. The binding propensity of cystathionine-beta-synthase domain to catalytic domain (through conserved water-mediated salt bridges) has provided a new insight to the biochemistry of IMPDH. Stereospecific interaction of IN with C2 domain through conserved water molecule (K109-W(II) 1-D215/D216) is observed to be unique in the simulated structure of hIMPDH-II. The geometrical/structural consequences and topological feature around the W(II) 1 water center may be utilized for isoform specific inhibitor design for CML cancer. An animated Interactive 3D Complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal :JBSD:1.

  12. Sellers floats into Node 1

    NASA Image and Video Library

    2010-05-16

    ISS023-E-041819 (16 May 2010) --- NASA astronaut Piers Sellers, STS-132 mission specialist, floats through a hatch on the International Space Station while space shuttle Atlantis remains docked with the station.

  13. De Winne floats through FGB

    NASA Image and Video Library

    2009-06-14

    ISS020-E-008936 (14 June 2009) --- European Space Agency astronaut Frank De Winne, Expedition 20 flight engineer, floats through the Zarya functional cargo block (FGB) of the International Space Station.

  14. De Winne floats through FGB

    NASA Image and Video Library

    2009-06-14

    ISS020-E-008938 (14 June 2009) --- European Space Agency astronaut Frank De Winne, Expedition 20 flight engineer, floats through the Zarya functional cargo block (FGB) of the International Space Station.

  15. NULL Convention Floating Point Multiplier

    PubMed Central

    Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069

  16. NULL convention floating point multiplier.

    PubMed

    Albert, Anitha Juliette; Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation.

  17. Control development for floating wind

    NASA Astrophysics Data System (ADS)

    Savenije, Feike; Peeringa, Johan

    2014-06-01

    Control of a floating wind turbine has proven to be challenging, but essential for lowering the cost of floating wind energy. Topic of a recent joint R&D project by GustoMSC, MARIN and ECN, is the concept design and verification with coupled simulations and model tests of the GustoMSC Tri-Floater. Only using an integral design approach, including mooring and control design, a cost effective system can be obtained. In this project, ECN developed a general floating wind turbine control strategy and applied this in a case study to the GustoMSC Tri-Floater and the OC3Hywind spar, both equipped with the NREL 5MW RWT. The designed controller ensures stable operation, while maintaining proper speed and power regulation. The motions of the floating support are reduced and substantial load reduction has been achieved.

  18. Electrically floating, near vertical incidence, skywave antenna

    SciTech Connect

    Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

    2014-07-08

    An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

  19. Lightweight Floating-Point Arithmetic: Case Study of Inverse Discrete Cosine Transform

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Chen, Tsuhan; Rutenbar, Rob A.

    2002-12-01

    To enable floating-point (FP) signal processing applications in low-power mobile devices, we propose lightweight floating-point arithmetic. It offers a wider range of precision/power/speed/area trade-offs, but is wrapped in forms that hide the complexity of the underlying implementations from both multimedia software designers and hardware designers. Libraries implemented in C++ and Verilog provide flexible and robust floating-point units with variable bit-width formats, multiple rounding modes and other features. This solution bridges the design gap between software and hardware, and accelerates the design cycle from algorithm to chip by avoiding the translation to fixed-point arithmetic. We demonstrate the effectiveness of the proposed scheme using the inverse discrete cosine transform (IDCT), in the context of video coding, as an example. Further, we implement lightweight floating-point IDCT into hardware and demonstrate the power and area reduction.

  20. Use of surface-geophysical methods to assess riverbed scour at bridge piers

    USGS Publications Warehouse

    Gorin, S.R.; Haeni, F.P.

    1989-01-01

    A ground-penetrating-radar system, and three seismic systems--color fathometer, tuned transducer, and black-and-white fathometer--were used to evaluate river-bed scour at the Charter Oak, Founder 's and Bulkeley Bridges in Hartford, Connecticut. Cross-sections of the channel and some lateral sections were run at each bridge in June and July 1987, and significant scour at piers supporting each of these bridges was recorded. Each of the four geophysical systems proved to have advantages and limitations. The ground penetrating radar system used single and dual 80 megahertz antennae floating in the water to transmit and receive the signal. The method was successful in water less than 25 ft deep, and in resistive earth materials. The geometry of existing scour holes and the extent of post-scour sedimentation were clearly defined. The color fathometer, operating at a signal frequency of 20 kilohertz, delineated existing scour-hole geometry, detected infilling of scour holes, and provided qualitative information about the physical properties of sediments. The tuned transducer, operating at a signal frequency of 14 kilohertz, defined scour-hole geometry and the extent of post-scour sediment deposition. Both of these systems were effective in water greater than 5 ft deep. At a signal frequency of 200 kilohertz, the black-and-white fathometer could not penetrate post-scour deposits, but it was useful in defining existing scour-holed geometry in water of any depth. (USGS)

  1. Evaporation mitigation by floating modular devices

    NASA Astrophysics Data System (ADS)

    Hassan, M. M.; Peirson, W. L.

    2016-05-01

    Prolonged periods of drought and consequent evaporation from open water bodies in arid parts of Australia continue to be a threat to water availability for agricultural production. Over many parts of Australia, the annual average evaporation exceeds the annual precipitation by more than 5 times. Given its significance, it is surprising that no evaporation mitigation technique has gained widespread adoption to date. High capital and maintenance costs of manufactured products are a significant barrier to implementation. The use of directly recycled clean plastic containers as floating modular devices to mitigate evaporation has been investigated for the first time. A six-month trial at an arid zone site in Australia of this potential cost effective solution has been undertaken. The experiment was performed using clean conventional drinking water bottles as floating modules on the open water surface of 240-L tanks with three varying degrees of covering (nil, 34% and 68%). A systematic reduction in evaporation is demonstrated during the whole study period that is approximately linearly proportional to the covered surface. These results provide a potential foundation for robust evaporation mitigation with the prospect of implementing a cost-optimal design.

  2. 14 CFR 25.533 - Hull and main float bottom pressures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the bottom plating and stringers and their attachments to the supporting structure, the following... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.533 Hull and main float bottom pressures. (a) General. The hull and main float structure, including frames and...

  3. 14 CFR 25.533 - Hull and main float bottom pressures.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the bottom plating and stringers and their attachments to the supporting structure, the following... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.533 Hull and main float bottom pressures. (a) General. The hull and main float structure, including frames and...

  4. 14 CFR 25.533 - Hull and main float bottom pressures.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the bottom plating and stringers and their attachments to the supporting structure, the following... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.533 Hull and main float bottom pressures. (a) General. The hull and main float structure, including frames and...

  5. 14 CFR 25.533 - Hull and main float bottom pressures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the bottom plating and stringers and their attachments to the supporting structure, the following... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.533 Hull and main float bottom pressures. (a) General. The hull and main float structure, including frames and...

  6. 14 CFR 25.533 - Hull and main float bottom pressures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the bottom plating and stringers and their attachments to the supporting structure, the following... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.533 Hull and main float bottom pressures. (a) General. The hull and main float structure, including frames and...

  7. 33 CFR 159.125 - Visible floating solids: Type I devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... expressed as milligrams per liter. This value must be 10 percent or less of the total suspended solids as... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Visible floating solids: Type I... Visible floating solids: Type I devices. During the sewage processing test (§ 159.121) 40 effluent samples...

  8. Students' Views of Floating & Sinking. Learning in Science Project (Primary). Working Paper No. 116.

    ERIC Educational Resources Information Center

    Biddulph, Fred

    This study investigated the meanings and ideas held and questions asked by children (ages 7-14) about floating and sinking (in water). Data were collected from interviews using "interview-about-instances" (IAI) cards (included in an appendix) and 10 objects which either floated or sank. Additional data were collected from classroom…

  9. 33 CFR 149.550 - What are the requirements for lights on a floating hose string?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... flashing yellow light. Lights on Buoys Used To Define Traffic Lanes ... lights on a floating hose string? 149.550 Section 149.550 Navigation and Navigable Waters COAST GUARD... EQUIPMENT Aids to Navigation Lights on Floating Hose Strings § 149.550 What are the requirements for lights...

  10. Students' Views of Floating & Sinking. Learning in Science Project (Primary). Working Paper No. 116.

    ERIC Educational Resources Information Center

    Biddulph, Fred

    This study investigated the meanings and ideas held and questions asked by children (ages 7-14) about floating and sinking (in water). Data were collected from interviews using "interview-about-instances" (IAI) cards (included in an appendix) and 10 objects which either floated or sank. Additional data were collected from classroom…

  11. Prototype Scale Mooring Load and Transmission Tests for a Floating Tire Breakwater.

    DTIC Science & Technology

    1978-04-01

    laboratory research into the wave transmission and mooring load characteristics of floating tire breakwaters. Kame l and Davidson (1968) conducted model...Floating Tire Break- waters ,” Marine Technical Report No. 54, University of Rhode Island, Kings ton , R.L , Apr. 1977. KAME L, A.M ., and DAVIDSON , D.D

  12. Climbing techniques for bridge inspection

    NASA Astrophysics Data System (ADS)

    Kaslan, Erol C.

    1998-03-01

    California has about 24,000 publicly owned bridges that require routine structural evaluations to comply with National Bridge Inspection Standard (NBIS) mandates. Of these, about 800 are identified as possessing fatigue prone or fracture critical details requiring thorough tactile investigations. Gaining access to bridge elements to perform these investigations has become increasingly difficult and costly. The traditional uses of under bridge inspection trucks, lift equipment and rigging are economically and practically limited by bridge size, structure type, traffic demands and support costs. In some cases, bridges that have become damaged by earthquakes cannot safely support the loads of heavy personnel lift equipment. The California Department of Transportation (Caltrans)'s Office of Structural Materials and Office of Structure Maintenance and Investigations evaluated the use of rock climbing and mountaineering techniques as an alternative means of gaining access for bridge inspections. Under a small research grant, a bridge climbing training course was developed through a local University of California outdoor recreation group and 7 engineers and technicians were initially trained. A comprehensive Code of Safe Practices was created and standards of training, procedures and equipment required for bridge inspections were established. A successful climb investigation on a large, previously inaccessible arch bridge was completed at the end of the training that proved the techniques safe, economical and effective. Within one year, 20 bridge maintenance engineers were trained, and a formal program was established to organize, schedule, equip and certify engineers and technicians for bridge climbing. Several other offices within Caltrans as well as the California Department of Water Resources have since adopted these techniques for specialized structural inspection tasks. Climbing techniques are now used routinely in California as an alterative means of gaining access

  13. Experimental procedures on floating offshore plate subjected to ground motion

    SciTech Connect

    Endo, Ryuji; Ando, Masahiro; Kato, Takehiko; Hamamoto, Takuji; Tosaka, Nobuyoshi

    1994-12-31

    This paper is concerned with experimental procedures for studying the dynamic behavior of floating offshore structures subjected to seaquakes. Three experimental procedures have been presented as vibration tests on the dynamic behavior of floating offshore structures. The first experimental procedure is performed using a large-scaled experimental water tank fitted with a vertical vibrator in the tank floor. The second one is carried out by using a small-scaled experimental water tank fitted with a vertical vibrator in the tank floor. The third one, which is the most convenient experimental procedure, is vibration tests of the cylindrical vessel in which the model is contained. Based on the experimental results, discussion focuses on the change in the seaquake response of flexible floating plate due to the plate flexibility and anchor stiffness through a comparative study of three experimental procedures.

  14. Floating into Thin Air

    SciTech Connect

    Hazi, A U

    2007-02-06

    On May 18, 2005, a giant helium balloon carrying the High Energy Focusing Telescope (HEFT) sailed into the spring sky over the deserts of New Mexico. The spindly steel and aluminum gondola that houses the optics, detectors, and other components of the telescope floated for 25 hours after its launch from Fort Sumner, New Mexico. For 21 of those hours, the balloon was nearly 40 kilometers above Earth's surface--almost four times higher than the altitude routinely flown by commercial jet aircraft. In the upper reaches of Earth's atmosphere, HEFT searched the universe for x-ray sources from highly energetic objects such as binary stars, galaxy clusters, and supermassive black holes. Before landing in Arizona, the telescope observed and imaged a dozen scientific targets by capturing photons emitted from these objects in the high-energy (hard) x-ray range (above 10 kiloelectronvolts). Among these targets were the Crab synchrotron nebula, the black hole Cygnus X-1 (one of the brightest x-ray sources in the sky), and the blazar 3C454.3. The scientific data gathered from these targets are among the first focused hard x-ray images returned from high altitudes.

  15. Vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction with solidification of floating organic droplet combined with flame atomic absorption spectrometry for the fast determination of cadmium in water samples.

    PubMed

    Peng, Guilong; Lu, Ying; He, Qiang; Mmereki, Daniel; Tang, Xiaohui; Zhong, Zhihui; Zhao, Xiaolong

    2016-01-01

    A novel vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction with solidification of floating organic droplet (VSLLME-SFO) was developed for the fast, simple and efficient determination of cadmium (Cd) in water samples followed by flame atomic absorption spectrometry (FAAS). In the VSLLME-SFO process, the addition of surfactant (as an emulsifier), could enhance the mass transfer from the aqueous solution into the extraction solvent. The extraction solvent could be dispersed into the aqueous phase under vigorous shaking with the vortex. In this paper, we investigated the influences of analytical parameters, including pH, extraction solvent type and its volume, surfactant type and its volume, concentration of chelating agent, salt effect and vortex time, on the extraction efficiency of Cd. Under the optimized conditions, the limit of detection was 0.16 μg/L. The analyte enrichment factor was 37.68. The relative standard deviation was 3.2% (10 μg/L, n = 10) and the calibration graph was linear, ranging from 0.5 to 30 μg/L. The proposed method was successfully applied for the analysis of ultra-trace Cd in river water and wastewater samples.

  16. 33 CFR 118.140 - Painting bridge piers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Painting bridge piers. 118.140 Section 118.140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.140 Painting bridge piers. The District Commander may require...

  17. 33 CFR 118.140 - Painting bridge piers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Painting bridge piers. 118.140 Section 118.140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.140 Painting bridge piers. The District Commander may require...

  18. 33 CFR 118.140 - Painting bridge piers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Painting bridge piers. 118.140 Section 118.140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.140 Painting bridge piers. The District Commander may require...

  19. 33 CFR 118.140 - Painting bridge piers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Painting bridge piers. 118.140 Section 118.140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.140 Painting bridge piers. The District Commander may require...

  20. 33 CFR 118.140 - Painting bridge piers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Painting bridge piers. 118.140 Section 118.140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.140 Painting bridge piers. The District Commander may require...

  1. Research effort aims at floating production technology

    SciTech Connect

    Not Available

    1992-08-17

    This paper reports that a 3 year research and development program on floating production systems (FPS), instigated by the Royal Norwegian Council for Scientific and Industrial Research (NTNF), has refined and qualified technologies for North Sea and arctic conditions. The FPS 2000 program, which cost 58 million kroner ($10 million), concentrated mainly on mooring systems and pipeline technology, along with new system concepts and cost reduction measures. More than 30 projects have been completed within the scheme. The anchoring and positioning project concentrates on developing methods for simulating behavior of mooring systems for large volume structures in deep water. It also seeks ways to determine efficiency of dynamic positioning thrusters under extreme conditions.

  2. Bathymetry in Petermann fjord from Operation IceBridge aerogravity

    NASA Astrophysics Data System (ADS)

    Tinto, Kirsty J.; Bell, Robin E.; Cochran, James R.; Münchow, Andreas

    2015-07-01

    Petermann Glacier is a major glacier in northern Greenland, maintaining one of the few remaining floating ice tongues in Greenland. Monitoring programs, such as NASA's Operation IceBridge have surveyed Petermann Glacier over several decades and have found it to be stable in terms of mass balance, velocity and grounding-line position. The future vulnerability of this large glacier to changing ocean temperatures and climate depends on the ocean-ice interactions beneath its floating tongue. These cannot currently be predicted due to a lack of knowledge of the bathymetry underneath the ice tongue. Here we use aerogravity data from Operation IceBridge, together with airborne radar and laser data and shipborne bathymetry-soundings to model the bathymetry beneath the Petermann ice tongue. We find a basement-cored inner sill at 540-610 m depth that results in a water cavity with minimum thickness of 400 m about 25 km from the grounding line. The sill is coincident with the location of the melt rate minimum. Seaward of the sill the fjord is strongly asymmetric. The deepest point occurs on the eastern side of the fjord at 1150 m, 600 m deeper than on the western side. This asymmetry is due to a sedimentary deposit on the western side of the fjord. A 350-410 m-deep outer sill, also mapped by marine surveys, marks the seaward end of the fjord. This outer sill is aligned with the proposed Last Glacial Maximum (LGM) grounding-line position for Petermann Glacier. The inner sill likely provided a stable pinning point for the grounding line in the past, punctuating the retreat of Petermann Glacier since the LGM.

  3. Ammonium, microcystins, and hypoxia of blooms in eutrophic water cause oxidative stress and C-N imbalance in submersed and floating-leaved aquatic plants in Lake Taihu, China.

    PubMed

    Zhang, Meng; Wang, Zhengqi; Xu, Jun; Liu, Yaqin; Ni, Leyi; Cao, Te; Xie, Ping

    2011-01-01

    The heavy bloom of cyanobacteria is a disastrous consequence of freshwater eutrophication, and the bloom is highly toxic due to its secondary metabolites called microcystins (MCs). The release of organic substances from dense blooms causes an increase in NH4+ and decrease in oxygen in lake water. In the present study, the dynamics of physio-biochemical responses of five aquatic macrophytes to MCs and NH4+ stresses in Meiliang Bay were evaluated. The bay is one of the most seriously eutrophized areas dominated by the toxic cyanobacteria of Lake Taihu, China. The results demonstrate that aquatic macrophytes in Meiliang Bay are subjected to successive external stresses. From January to May, they are subjected to high NH4+ stress (>0.56 mg L(-1)), whereas from June to September or during dense blooms, the macrophytes experience both MC proliferation and moderate NH4+ toxicity (>0.3 mg L(-1)). In August, high NH4+ stress occurs along with hypoxia stress, whereas from September to December, the macrophytes experience moderate NH4+ stress, causing a serious imbalance in C-N metabolism and oxidative stress. Between the two aquatic plant life forms, floating-leaved plants are more resistant to the stresses of eutrophication than are submersed plants. Elevated MCs in the water column can aggravate oxidative stress and suppress the soluble protein contents of aquatic plants. High NH4+ in the water causes severe C and N imbalance in submersed macrophytes because of considerable carbon consumption for free amino acid synthesis. The superoxide dismutase activities of submersed macrophytes are suppressed by low light penetrating the eutrophic water, which might impair the antioxidative function of the plants. The findings of this study provide mainly field evidence that reveals the physical, chemical, and biological stresses on aquatic plants in bloom-prevailed eutrophic lakes. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Dispersive liquid-phase microextraction with solidification of floating organic droplet coupled with high-performance liquid chromatography for the determination of Sudan dyes in foodstuffs and water samples.

    PubMed

    Chen, Bo; Huang, Yuming

    2014-06-25

    Dispersive liquid-phase microextraction with solidification of floating organic drop (SFO-DLPME) is one of the most interesting sample preparation techniques developed in recent years. In this paper, a new, rapid, and efficient SFO-DLPME coupled with high-performance liquid chromatography (HPLC) was established for the extraction and sensitive detection of banned Sudan dyes, namely, Sudan I, Sudan II, Sudan III, and Sudan IV, in foodstuff and water samples. Various factors, such as the type and volume of extractants and dispersants, pH and volume of sample solution, extraction time and temperature, ion strength, and humic acid concentration, were investigated and optimized to achieve optimal extraction of Sudan dyes in one single step. After optimization of extraction conditions using 1-dodecanol as an extractant and ethanol as a dispersant, the developed procedure was applied for extraction of the target Sudan dyes from 2 g of food samples and 10 mL of the spiked water samples. Under the optimized conditions, all Sudan dyes could be easily extracted by the proposed SFO-DLPME method. Limits of detection of the four Sudan dyes obtained were 0.10-0.20 ng g(-1) and 0.03 μg L(-1) when 2 g of foodstuff samples and 10 mL of water samples were adopted, respectively. The inter- and intraday reproducibilities were below 4.8% for analysis of Sudan dyes in foodstuffs. The method was satisfactorily used for the detection of Sudan dyes, and the recoveries of the target for the spiked foodstuff and water samples ranged from 92.6 to 106.6% and from 91.1 to 108.6%, respectively. These results indicated that the proposed method is simple, rapid, sensitive, and suitable for the pre-concentration and detection of the target dyes in foodstuff samples.

  5. Determination of hormones, a plasticizer, preservatives, perfluoroalkylated compounds, and a flame retardant in water samples by ultrasound-assisted dispersive liquid-liquid microextraction based on the solidification of a floating organic drop.

    PubMed

    Martín, Julia; Santos, Juan Luis; Aparicio, Irene; Alonso, Esteban

    2015-10-01

    Dispersive liquid-liquid microextraction based on the solidification of a floating organic drop (DLLME-SFO) is a novel extraction technique commonly applied for the extraction on a specific group of compounds. In this paper, the applicability of ultrasound-assisted DLLME-SFO for multiresidue extraction has been evaluated. A method for the simultaneous extraction of four hormones (17α-ethinylestradiol, 17β-estradiol, estriol and estrone), a plasticizer (bisphenol A), three preservatives (methyl-, ethyl- and propylparaben), six perfluoroalkylated compounds (perfluorooctane sulfonic acid and five perfluoroalkyl carboxylic acids, from C4 to C8), and a brominated flame retardant (hexabromocyclododecane) has been developed and validated for their extraction from surface water and tap water. Determination was carried out by high-performance liquid chromatography-tandem mass spectrometry in negative ionization mode. Recoveries of the target compounds were highly dependent on their log K(ow) values. Linear relationship between recoveries and log K(ow) values was observed for compounds from the same group (hormones, preservatives and perfluoroalkylated carboxylic acids). The lowest recoveries were obtained for the less hydrophobic compounds (estriol (43%), methylparaben (32%), ethylparaben (45%) and the perfluorinated compounds of shorter alkyl chain (C4: 17%, C5: 41% and C6: 57%)). Recoveries of the other pollutants were higher than 80%. Precision, expressed as relative standard deviation, was in the range from 1% to 16%. Method detection limits were in the range 0.001-1.126 µg L(-1), for surface water, and 0.001-1.446 µg L(-1) for tap water. No important matrix effect was observed. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Floating treatment wetlands for domestic wastewater treatment.

    PubMed

    Faulwetter, J L; Burr, M D; Cunningham, A B; Stewart, F M; Camper, A K; Stein, O R

    2011-01-01

    Floating islands are a form of treatment wetland characterized by a mat of synthetic matrix at the water surface into which macrophytes can be planted and through which water passes. We evaluated two matrix materials for treating domestic wastewater, recycled plastic and recycled carpet fibers, for chemical oxygen demand (COD) and nitrogen removal. These materials were compared to pea gravel or open water (control). Experiments were conducted in laboratory scale columns fed with synthetic wastewater containing COD, organic and inorganic nitrogen, and mineral salts. Columns were unplanted, naturally inoculated, and operated in batch mode with continuous recirculation and aeration. COD was efficiently removed in all systems examined (>90% removal). Ammonia was efficiently removed by nitrification. Removal of total dissolved N was ∼50% by day 28, by which time most remaining nitrogen was present as NO(3)-N. Complete removal of NO(3)-N by denitrification was accomplished by dosing columns with molasses. Microbial communities of interest were visualized with denaturing gradient gel electrophoresis (DGGE) by targeting specific functional genes. Shifts in the denitrifying community were observed post-molasses addition, when nitrate levels decreased. The conditioning time for reliable nitrification was determined to be approximately three months. These results suggest that floating treatment wetlands are a viable alternative for domestic wastewater treatment.

  7. A laboratory study of floating lenticular anticyclones

    NASA Astrophysics Data System (ADS)

    Le Gal, Patrice; de La Rosa, Hector; Cros, Anne; Cruz-Gomez, Raúl; Le Bars, Michael

    2014-11-01

    Oceanic vortices play an important role in the redistribution of heat, salt and momentum in the oceans. Among these vortices, floating lenses or rings are often met in the meanders of warm currents. For instance the North Brazil Current rings are among the most intense and large anticyclonic vortices on Earth. In order to better describe these vortices, we propose here a laboratory study of these floating anticyclonic lenses. A blob of fresh water is slowly injected near the surface of a rotating layer of homogeneous salted water. Because of the opposite effects of rotation that tends to generate columnar structures and density stratification that spreads light water on the surface, the vortices take a finite size three dimensionnal typical shape. Visualization and PIV measurements of the shape, aspect ratios and vorticity profiles are compared to analytical predictions that use first a simple solid body rotation model and then a more realistic isolated Gaussian vorticity field inside the anticyclones. This work was carried out within the framework of a bilateral cooperation between CNRS (France) and CONACYT (Mexico).

  8. Capillary self-assembly of floating bodies

    NASA Astrophysics Data System (ADS)

    Jung, Sunghwan; Thompson, Paul; Bush, John

    2007-11-01

    We study the self-assembly of bodies supported on the water surface by surface tension. Attractive and repulsive capillary forces exist between menisci of, respectively, the same and opposite signs. In nature, floating objects (e.g. mosquito larvae) thus interact through capillary forces to form coherent packings on the water surface. We here present the results of an experimental investigation of such capillary pattern formation. Thin elliptical metal sheets were designed to have variable shape, flexibility and mass distribution. On the water surface, mono-, bi-, or tri-polar menisci could thus be achieved. The influence of the form of the menisci on the packings arising from the interaction of multiple floaters is explored. Biological applications are discussed.

  9. Floating Wetland Islands Help Restore Large PA Lake

    EPA Pesticide Factsheets

    One of Pennsylvania’s largest natural lakes has been removed from the state’s list of impaired waters following years of EPA-funded work to control phosphorus pollution. One of the innovative actions taken to meet the goal was use of 5 floating wetlands.

  10. Floating Wetland Islands Help Restore Large Pennsylvania Lake

    EPA Pesticide Factsheets

    One of Pennsylvania’s largest lakes has been removed from the list of impaired waters following years of EPA-funded work to control phosphorus pollution. One of the innovative actions taken to meet the goal was deployment of five floating wetland islands.

  11. Vibrations of a floating beam on marine waves

    SciTech Connect

    Sabaneev, Valentin S.; Tovstik, Petr E.; Tovstik, Tatiana M.; Shekhovtsov, Alexei S.

    2015-03-10

    Vertical vibrations of a floating pipe-concrete beam caused by a harmonic waves excitation are studied. The apparent additional mass of water, resisting force and the velocity of towing are considered. The vibration amplitude and the maximum deformations of concrete, caused by these fluctuations, are calculated.

  12. Experimental and Numerical Investigations of Floating Breakwater Performance.

    USDA-ARS?s Scientific Manuscript database

    Floating breakwaters are commonly used to protect small marinas and for shoreline erosion control in coastal areas. They are efficient wave attenuation structures for relatively short waves and shallow water depths. The main objective of the current study is to investigate the hydrodynamic interacti...

  13. Speciation of As(III) and As(V) in water samples by graphite furnace atomic absorption spectrometry after solid phase extraction combined with dispersive liquid-liquid microextraction based on the solidification of floating organic drop.

    PubMed

    Shamsipur, Mojtaba; Fattahi, Nazir; Assadi, Yaghoub; Sadeghi, Marzieh; Sharafi, Kiomars

    2014-12-01

    A solid phase extraction (SPE) coupled with dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) method, using diethyldithiphosphate (DDTP) as a proper chelating agent, has been developed as an ultra preconcentration technique for the determination of inorganic arsenic in water samples prior to graphite furnace atomic absorption spectrometry (GFAAS). Variables affecting the performance of both steps were thoroughly investigated. Under optimized conditions, 100mL of As(ΙΙΙ) solution was first concentrated using a solid phase sorbent. The extract was collected in 2.0 mL of acetone and 60.0 µL of 1-undecanol was added into the collecting solvent. The mixture was then injected rapidly into 5.0 mL of pure water for further DLLME-SFO. Total inorganic As(III, V) was extracted similarly after reduction of As(V) to As(III) with potassium iodide and sodium thiosulfate and As(V) concentration was calculated by difference. A mixture of Pd(NO3)2 and Mg(NO3)2 was used as a chemical modifier in GFAAS. The analytical characteristics of the method were determined. The calibration graph was linear in the rage of 10-100 ng L(-1) with detection limit of 2.5 ng L(-1). Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 80 ng L(-1) of As(ΙΙΙ) were 6.8% and 7.5%, respectively. The method was successfully applied to speciation of As(III), As(V) and determination of the total amount of As in water samples and in a certified reference material (NIST RSM 1643e).

  14. The paradox of the floating candle that continues to burn

    NASA Astrophysics Data System (ADS)

    Theodorakis, Stavros; Aristidou, Charalambos

    2012-08-01

    What happens after lighting a paraffin candle that is barely floating in water and kept upright with the aid of an appropriately weighted nail attached to its bottom? Presumably, it should sink because the buoyant force will decrease more than the weight. Surprisingly, the candle will continue to burn, rising slowly above the surface of the water. The reason for this is that the flame forms a well around the wick filled with molten paraffin, while the water keeps the outer walls of the candle cool and unscathed. Thus, the buoyancy hardly changes while the weight is reduced through burning, resulting in a floating candle that will rise above water. We present a quantitative model that describes the formation of the well and verify it experimentally, examining first the case of a candle in the air and then the case of a candle immersed in water.

  15. Effect of combined ecological floating bed for eutrophic lake remediation

    NASA Astrophysics Data System (ADS)

    Zheng, Liguo; Wang, Haiping

    2017-05-01

    A novel combined ecological floating bed(CEFB) integrated high-density hydrophyte and aquatic animals, the wave-making equipments, water cycling automatic aerators and fluorescence inducing equipments. The water quality of a eutrophic lake was improved significantly after three months remediation of CEFB. Compared with the background value, the results showed that the removal efficiencies of total nitrogen (TN), ammonia(NH3-N), total phosphorous(TP) and chemical oxygen demand (COD) in the water reached 31.5%, 33%, 30.5% and 53%, respectively. CEFB could manipulate biotic interactions in the aquatic ecosystem, and then absorb eutrophic material efficiently by the co-effect of floating the sediment slowly, refreshing the static eutrophic water body, changing the photosynthetic and biochemical environment of the eutrophic water body and inducing plankton directional movement. At the same time, plants and fish grew good in CEFB,which can bring economic income to some extent.

  16. Evaporation mitigation using floating modular devices

    NASA Astrophysics Data System (ADS)

    Hassan, M. Mahmudul; Peirson, William Leslie; Neyland, Bryce M.; Fiddis, Nicholas McQuistan

    2015-11-01

    Reducing evaporation losses from open water storages is of paramount importance in the improvement of water security in arid countries, including Australia. Widespread adoption of evaporation mitigation techniques has been prevented by their high capital and maintenance or operating costs. The use of clean, floating recycled materials to mitigate evaporation technique has been investigated systematically at sites within both the coastal and semi-arid zones of Australia. Evaporation reduction systematically increases with the proportion of covered surface. Evaporation is reduced by 43% at coastal site and 37% at arid zone site at the maximum packing densities achievable for a single layer of floating devices. The study highlights the importance of both long-term investigations and the climatic influences in the robust quantification of evaporation mitigation. The effects of solar radiation, temperature, wind speed and relative humidity on the evaporation rate at both study sites have been determined in terms of both the classical Penman model and FAO Penman Monteith model with corresponding pan coefficients quantified. FAO Penman Monteith model better estimates evaporation from the open reference tank.

  17. Detection of Floating Inputs in Logic Circuits

    NASA Technical Reports Server (NTRS)

    Cash, B.; Thornton, M. G.

    1984-01-01

    Simple modification of oscilloscope probe allows easy detection of floating inputs or tristate outputs in digital-IC's. Oscilloscope probe easily modified with 1/4 W resistor and switch for detecting floating inputs in CMOS logic circuits.

  18. Detection of Floating Inputs in Logic Circuits

    NASA Technical Reports Server (NTRS)

    Cash, B.; Thornton, M. G.

    1984-01-01

    Simple modification of oscilloscope probe allows easy detection of floating inputs or tristate outputs in digital-IC's. Oscilloscope probe easily modified with 1/4 W resistor and switch for detecting floating inputs in CMOS logic circuits.

  19. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 15 2011-07-01 2011-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection of Environment ENVIRONMENTAL PROTECTION... External floating roof converted into an internal floating roof. The owner or operator who elects to...

  20. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 16 2014-07-01 2014-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection of Environment ENVIRONMENTAL PROTECTION... External floating roof converted into an internal floating roof. The owner or operator who elects to...

  1. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 16 2013-07-01 2013-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection of Environment ENVIRONMENTAL PROTECTION... External floating roof converted into an internal floating roof. The owner or operator who elects to...

  2. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 16 2012-07-01 2012-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection of Environment ENVIRONMENTAL PROTECTION... External floating roof converted into an internal floating roof. The owner or operator who elects to...

  3. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 15 2010-07-01 2010-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection of Environment ENVIRONMENTAL PROTECTION... External floating roof converted into an internal floating roof. The owner or operator who elects...

  4. The Aerodynamic Drag of Five Models of Side Floats N.A.C.A. Models 51-E, 51-F, 51-G, 51-H, 51-J

    NASA Technical Reports Server (NTRS)

    House, R O

    1938-01-01

    The drag of five models of side floats was measured in the N.A.C.A. 7- by 10-foot wind tunnel. The most promising method of reducing the drag of floats indicated by these tests is lowering the angle at which the floats are rigged. The addition of a step to a float does not always increase the drag in the flying range, floats with steps sometimes having lower drag than similar floats without steps. Making the bow chine no higher than necessary might result in a reduction in air drag because of the lower angle of pitch of the chines. Since side floats are used formally to obtain lateral stability when the seaplane is operating on the water at slow speeds or at rest, greater consideration can be given to factors affecting aerodynamic drag than is possible for other types of floats and hulls.

  5. 14 CFR 23.531 - Hull and main float takeoff condition.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Water Loads § 23.531 Hull and main float takeoff condition. For the wing and its attachment to the hull or main float— (a) The aerodynamic wing lift is assumed to be zero; and (b) A downward inertia...

  6. 14 CFR 23.531 - Hull and main float takeoff condition.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Water Loads § 23.531 Hull and main float takeoff condition. For the wing and its attachment to the hull or main float— (a) The aerodynamic wing lift is assumed to be zero; and (b) A downward inertia...

  7. 14 CFR 23.531 - Hull and main float takeoff condition.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Water Loads § 23.531 Hull and main float takeoff condition. For the wing and its attachment to the hull or main float— (a) The aerodynamic wing lift is assumed to be zero; and (b) A downward inertia...

  8. 32 CFR 935.165 - Floating objects.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Floating objects. 935.165 Section 935.165... REGULATIONS WAKE ISLAND CODE Public Safety § 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location or manner other than as...

  9. Have Floating Rates Been a Success?

    ERIC Educational Resources Information Center

    Higham, David

    1983-01-01

    Floating exchange rates have not lived up to all expectations, but neither have they performed as badly as some critics have suggested. Examined are the impact of floating rates on balance of payments adjustment, domestic economic policy, and inflation and the claim that floating rates have displayed excessive fluctuations. (Author/RM)

  10. New Directions in Floating-Point Arithmetic

    NASA Astrophysics Data System (ADS)

    Beebe, Nelson H. F.

    2007-12-01

    This article briefly describes the history of floating-point arithmetic, the development and features of IEEE standards for such arithmetic, desirable features of new implementations of floating-point hardware, and discusses work-in-progress aimed at making decimal floating-point arithmetic widely available across many architectures, operating systems, and programming languages.

  11. Have Floating Rates Been a Success?

    ERIC Educational Resources Information Center

    Higham, David

    1983-01-01

    Floating exchange rates have not lived up to all expectations, but neither have they performed as badly as some critics have suggested. Examined are the impact of floating rates on balance of payments adjustment, domestic economic policy, and inflation and the claim that floating rates have displayed excessive fluctuations. (Author/RM)

  12. Effect of interfibrillar PVA bridging on water stability and mechanical properties of TEMPO/NaClO2 oxidized cellulosic nanofibril films.

    PubMed

    Hakalahti, Minna; Salminen, Arto; Seppälä, Jukka; Tammelin, Tekla; Hänninen, Tuomas

    2015-08-01

    TEMPO/NaClO2 oxidized cellulosic nanofibrils (TCNF) were covalently bonded with poly(vinyl alcohol) (PVA) to render water stable films. Pure TCNF films and TCNF-PVA films in dry state showed similar humidity dependent behavior in the elastic region. However, in wet films PVA had a significant effect on stability and mechanical characteristics of the films. When soaked in water, pure TCNF films exhibited strong swelling behavior and poor wet strength, whereas covalently bridged TCNF-PVA composite films remained intact and could easily be handled even after 24h of soaking. Wet tensile strength of the films was considerably enhanced with only 10 wt% PVA addition. At 25% PVA concentration wet tensile strengths were decreased and films were more yielding. This behavior is attributed to the ability of PVA to reinforce and plasticize TCNF-based films. The developed approach is a simple and straightforward method to produce TCNF films that are stable in wet conditions.

  13. Float It Down the River.

    ERIC Educational Resources Information Center

    Brendzel, Sharon; Orfan, Lucy; Schuhmacher, Robert

    2000-01-01

    Presents an activity that involves students in a hands-on, creative project in which they use higher order thinking skills while designing and studying the basics of floating devices. Focuses on inquiry, a number of scientific principles, and the relationship between mathematics and science. (ASK)

  14. Floating Ring-Groove Lapper

    NASA Technical Reports Server (NTRS)

    Williams, Robert L., Sr.; Williams, Robert L., Jr.; Chase, Timothy L.

    1992-01-01

    Tool fits out-of-round seal groove and laps it to fine finish without binding. Includes floating lapping pieces riding freely in groove, and are curved to match nominal diameter of groove. One lapping piece tightened so it does not move relative to disk.

  15. Designing seaplane hulls and floats

    NASA Technical Reports Server (NTRS)

    Benoit,

    1926-01-01

    Experimental data, such as the results of tank tests of models, render it possible to predict, at least in principle, as to how a hull or float of a given shape will comport itself. We will see further along, however, how uncertain these methods are and how they leave room for empiricism, which will reign for a long time yet in seaplane research bureaus.

  16. Floating Ring-Groove Lapper

    NASA Technical Reports Server (NTRS)

    Williams, Robert L., Sr.; Williams, Robert L., Jr.; Chase, Timothy L.

    1992-01-01

    Tool fits out-of-round seal groove and laps it to fine finish without binding. Includes floating lapping pieces riding freely in groove, and are curved to match nominal diameter of groove. One lapping piece tightened so it does not move relative to disk.

  17. Apple Floating in Cupola Module

    NASA Image and Video Library

    2014-02-06

    ISS038-E-042112 (6 Feb. 2014) --- A fresh apple floating freely near a window in the Cupola of the International Space Station is featured in this image photographed by an Expedition 38 crew member. Currently docked to the station, a Russian Progress resupply vehicle (left) and a Soyuz spacecraft along with Earth's horizon are visible in the background.

  18. Fruit Floating at Cupola Window

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029073 (12 Jan. 2014) --- A fresh apple floating freely near a window in the Cupola of the International Space Station is featured in this image photographed by an Expedition 38 crew member. Attached to the Harmony node, the Orbital Sciences Corp. Cygnus commercial cargo craft, which brought the fresh fruit, is visible at center.

  19. Apple Floating in Cupola Module

    NASA Image and Video Library

    2014-02-06

    ISS038-E-042121 (6 Feb. 2014) --- A fresh apple floating freely near a window in the Cupola of the International Space Station is featured in this image photographed by an Expedition 38 crew member. The bright sun and Earth's horizon provide the backdrop for the scene.

  20. Software Bridge

    NASA Technical Reports Server (NTRS)

    1995-01-01

    I-Bridge is a commercial version of software developed by I-Kinetics under a NASA Small Business Innovation Research (SBIR) contract. The software allows users of Windows applications to gain quick, easy access to databases, programs and files on UNIX services. Information goes directly onto spreadsheets and other applications; users need not manually locate, transfer and convert data.