WorldWideScience

Sample records for stabilized water levels

  1. Stability Analysis of Hydrodynamic Pressure Landslides with Different Permeability Coefficients Affected by Reservoir Water Level Fluctuations and Rainstorms

    Directory of Open Access Journals (Sweden)

    Faming Huang

    2017-06-01

    Full Text Available It is significant to study the variations in the stability coefficients of hydrodynamic pressure landslides with different permeability coefficients affected by reservoir water level fluctuations and rainstorms. The Sifangbei landslide in Three Gorges Reservoir area is used as case study. Its stability coefficients are simulated based on saturated-unsaturated seepage theory and finite element analysis. The operating conditions of stability coefficients calculation are reservoir water level variations between 175 m and 145 m, different rates of reservoir water level fluctuations, and a three-day continuous rainstorm. Results show that the stability coefficient of the hydrodynamic pressure landslide decreases with the drawdown of the reservoir water level, and a rapid drawdown rate leads to a small stability coefficient when the permeability coefficient ranges from 1.16 × 10−6 m/s to 4.64 × 10−5 m/s. Additionally, the landslide stability coefficient increases as the reservoir water level increases, and a rapid increase in the water level leads to a high stability coefficient when the permeability coefficient ranges from 1.16 × 10−6 m/s to 4.64 × 10−5 m/s. The landslide stability coefficient initially decreases and then increases as the reservoir water level declines when the permeability coefficient is greater than 4.64 × 10−5 m/s. Moreover, for structures with the same landslide, the landslide stability coefficient is most sensitive to the change in the rate of reservoir water level drawdown when the permeability coefficient increases from 1.16 × 10−6 m/s to 1.16 × 10−4 m/s. Additionally, the rate of decrease in the stability coefficient increases as the permeability coefficient increases. Finally, the three-day rainstorm leads to a significant reduction in landslide stability, and the rate of decrease in the stability coefficient initially increases and then decreases as the permeability coefficient increases.

  2. Determination of an acceptable assimilable organic carbon (AOC) level for biological stability in water distribution systems with minimized chlorine residual.

    Science.gov (United States)

    Ohkouchi, Yumiko; Ly, Bich Thuy; Ishikawa, Suguru; Kawano, Yoshihiro; Itoh, Sadahiko

    2013-02-01

    There is considerable interest in minimizing the chlorine residual in Japan because of increasing complaints about a chlorinous odor in drinking water. However, minimizing the chlorine residual causes the microbiological water quality to deteriorate, and stricter control of biodegradable organics in finished water is thus needed to maintain biological stability during water distribution. In this investigation, an acceptable level of assimilable organic carbon (AOC) for biologically stable water with minimized chlorine residual was determined based on the relationship between AOC, the chlorine residual, and bacterial regrowth. In order to prepare water samples containing lower AOC, the fractions of AOC and biodegradable organic matter (BOM) in tap water samples were reduced by converting into biomass after thermal hydrolysis of BOM at alkaline conditions. The batch-mode incubations at different conditions of AOC and chlorine residual were carried out at 20 °C, and the presence or absence of bacterial regrowth was determined. The determined curve for biologically stable water indicated that the acceptable AOC was 10.9 μg C/L at a minimized chlorine residual (0.05 mg Cl(2)/L). This result indicated that AOC removal during current water treatment processes in Japan should be significantly enhanced prior to minimization of the chlorine residual in water distribution.

  3. Reactor water level control device

    International Nuclear Information System (INIS)

    Hiramatsu, Yohei.

    1980-01-01

    Purpose: To increase the rapid response of the waterlevel control converting a reactor water level signal into a non-linear type, when the water level is near to a set value, to stabilize the water level reducting correlatively the reactor water level variation signal to stabilize greatly from the set value, and increasing the variation signal. Constitution: A main vapor flow quality transmitter detects the vapor flow generated in a reactor and introduced into a turbine. A feed water flow transmitter detects the quantity of a feed water flow from the turbine to the reactor, this detected value is sent to an addition operating apparatus. On the other hand, the power signal of the reactor water level transmitter is sent to the addition operating apparatus through a non-linear water level signal converter. The addition operation apparatus generates a signal for requesting the feed water flow quantity from both signals. Upon this occasion, the reactor water level signal converter makes small the reactor water level variation when the reactor level is close the set value, and when the water level deviates greatly from the set value, the reactor water level variation is made large thereby to improve the rapid response of the reactor coater level control. (Yoshino, Y.)

  4. Water-stabilized plasma generators

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan

    1998-01-01

    Roč. 70, č. 6 (1998), s. 1157-1162 ISSN 0033-4545 R&D Projects: GA ČR GA102/95/0592; GA ČR GV106/96/K245 Institutional research plan: CEZ:AV0Z2043910 Keywords : thermal plasma, plasma torch, water -stabilized plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.677, year: 1998

  5. Water Level Station History

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Images contain station history information for 175 stations in the National Water Level Observation Network (NWLON). The NWLON is a network of long-term,...

  6. Reactor water level control device and water level control method

    International Nuclear Information System (INIS)

    Kawamura, Shin-ichiro; Habuka, Minoru.

    1996-01-01

    The present invention provide a device of and a method for controlling fluctuation of reactor water level caused upon insertion of selected control rods performed in order to ensure reactor stability when recycling pumps of a BWR-type power plant are stopped. When it is detected that reactor operation determined by reactor power and reactor core flow rate reaches unstable region after stoppage of a portion of the recycling pumps, the speed of integral recycling pumps is lowered to a predetermined speed of revolution conducted together with the insertion of selected control rods to suppress fluctuation of the reactor water level. Namely, (1) a recycling pump state monitoring device receives recycling pump state signals as an input and outputs recycling pump stopping detection signals. (2) A selected control rod insertion operation demand judging device judges the insurance of reactor stability due to insertion of the selected control rods and outputs selected control rod insertion operation demand signals. (3) A recycling pump speed control device outputs recycling pump speed control signals to control reactor core flow rate. (4) A minimum flow rate control valve controlling device outputs minimum flow rate control valve opening operation demand signals after a predetermined period of time. (5) A feed water pump minimum flow rate control valve is disposed to a feed water pump bypass channel and operated by the output signals of the device (4). (I.S.)

  7. Structure and stability of spiro-cyclic water clusters

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The structure and stability of spiro-cyclic water clusters containing up to 32 water molecules have been investigated at different levels of theory. Although there exist minima lower in energy than these spiro-cyclic clusters, calculations at the Hartree–Fock level, density functional theory using B3LYP parametrization ...

  8. Stability of water on Mars.

    Science.gov (United States)

    Sears, D. W. G.; Moore, S. R.

    2004-11-01

    In order to try to quantify some of the factors determining the evaporation rate of water on Mars, we have been measuring evaporation rates under simulated martian conditions in a large planetary environmental chamber. All of our experiments have been performed at 5.25 Torr (7 mb) total pressure, but we have varied the temperature of the water surface, atmosphere and walls of the chamber (the walls we assume to be somewhat analogous to surrounding surfaces on Mars). We have also monitored the partial pressure of water vapor in the atmosphere to investigate its effect on evaporation rate. Most importantly, we have attempted to model the effect of advection - physical removal of the water vapor by wind or other forms of atmospheric motion - by (1) placing a bag of dry ice in the chamber and (2) by installing a copper cold finger with circulating methanol/dry ice slurry next to the sample and pumping as necessary to maintain 5.25 Torr. As might be expected, the situation is complicated and not readily described theoretically, but several conclusions seem to be emerging. Evaporation rates under nonadvective conditions are 1.2 mm/h and decrease only by about 30% as water vapor builds up in the atmosphere to as much as 40 vol %. Wall temperature and water surface temperature do not appear to affect evaporation rates significantly, but a 20 C increase in atmospheric temperature causes a 40% increase in evaporation rate. The evaporation rate increases by a factor of two in the presence of advection and under advective conditions is not affected significantly by changes in water, air, or wall temperature, or water vapor pressure. These results suggest that atmospheric motion may be the dominant factor in determining water evaporation on Mars.

  9. Fermi level stabilization energy in cadmium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Speaks, D. T.; Mayer, M. A.; Yu, K. M.; Mao, S. S.; Haller, E. E.; Walukiewicz, W.

    2010-04-08

    We have studied the effects of high concentrations of native point defects on the electrical and optical properties of CdO. The defects were introduced by irradiation with high energy He+, Ne+, Ar+ and C+ ions. Increasing the irradiation damage with particles heavier than He+ increases the electron concentration until a saturation level of 5x1020 cm-3 is reached. In contrast, due to the ionic character and hence strong dynamic annealing of CdO, irradiation with much lighter He+ stabilizes the electron concentration at a much lower level of 1.7x1020 cm-3. A large shift of the optical absorption edge with increasing electron concentration in irradiated samples is explained by the Burstein-Moss shift corrected for electron-electron and electron-ion interactions. The saturation of the electron concentration and the optical absorption edge energy are consistent with a defect induced stabilization of the Fermi energy at 1 eV above the conduction band edge. The result is in a good agreement with previously determined Fermi level pinning energies on CdO surfaces. The results indicate that CdO shares many similarities with InN, as both materials exhibit extremely large electron affinities and an unprecedented propensity for n-type conductivity.

  10. Reaction of PFCs in water stabilized plasma

    Czech Academy of Sciences Publication Activity Database

    Mastný, L.; Horníček, J.; Živný, Oldřich; Brožek, Vlastimil; Sember, Viktor

    2017-01-01

    Roč. 13, č. 1 (2017), s. 161 ISSN 1336-7242. [Zjazd chemikov /69./. 11.09.2017-15.09.2017, Horný Smokovec] R&D Projects: GA ČR(CZ) GC17-10246J Institutional support: RVO:61389021 Keywords : Water stabilized plasma * tetrafluoromethane * corrosion resistance * boron nitride * titanium nitride Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics)

  11. Optimality versus stability in water resource allocation.

    Science.gov (United States)

    Read, Laura; Madani, Kaveh; Inanloo, Bahareh

    2014-01-15

    Water allocation is a growing concern in a developing world where limited resources like fresh water are in greater demand by more parties. Negotiations over allocations often involve multiple groups with disparate social, economic, and political status and needs, who are seeking a management solution for a wide range of demands. Optimization techniques for identifying the Pareto-optimal (social planner solution) to multi-criteria multi-participant problems are commonly implemented, although often reaching agreement for this solution is difficult. In negotiations with multiple-decision makers, parties who base decisions on individual rationality may find the social planner solution to be unfair, thus creating a need to evaluate the willingness to cooperate and practicality of a cooperative allocation solution, i.e., the solution's stability. This paper suggests seeking solutions for multi-participant resource allocation problems through an economics-based power index allocation method. This method can inform on allocation schemes that quantify a party's willingness to participate in a negotiation rather than opt for no agreement. Through comparison of the suggested method with a range of distance-based multi-criteria decision making rules, namely, least squares, MAXIMIN, MINIMAX, and compromise programming, this paper shows that optimality and stability can produce different allocation solutions. The mismatch between the socially-optimal alternative and the most stable alternative can potentially result in parties leaving the negotiation as they may be too dissatisfied with their resource share. This finding has important policy implications as it justifies why stakeholders may not accept the socially optimal solution in practice, and underlies the necessity of considering stability where it may be more appropriate to give up an unstable Pareto-optimal solution for an inferior stable one. Authors suggest assessing the stability of an allocation solution as an

  12. Reactor water level control device

    International Nuclear Information System (INIS)

    Utagawa, Kazuyuki.

    1993-01-01

    A device of the present invention can effectively control fluctuation of a reactor water level upon power change by reactor core flow rate control operation. That is, (1) a feedback control section calculates a feedwater flow rate control amount based on a deviation between a set value of a reactor water level and a reactor water level signal. (2) a feed forward control section forecasts steam flow rate change based on a reactor core flow rate signal or a signal determining the reactor core flow rate, to calculate a feedwater flow rate control amount which off sets the steam flow rate change. Then, the sum of the output signal from the process (1) and the output signal from the process (2) is determined as a final feedwater flow rate control signal. With such procedures, it is possible to forecast the steam flow rate change accompanying the reactor core flow rate control operation, thereby enabling to conduct preceding feedwater flow rate control operation which off sets the reactor water level fluctuation based on the steam flow rate change. Further, a reactor water level deviated from the forecast can be controlled by feedback control. Accordingly, reactor water level fluctuation upon power exchange due to the reactor core flow rate control operation can rapidly be suppressed. (I.S.)

  13. Fuel traps: mapping stability via water association.

    Energy Technology Data Exchange (ETDEWEB)

    Rempe, Susan L.; Clawson, Jacalyn S.; Greathouse, Jeffery A.; Alam, Todd M; Leung, Kevin; Varma, Sameer; Sabo, Dubravko; Martin, Marcus Gary; Cygan, Randall Timothy

    2007-03-01

    Hydrogen storage is a key enabling technology required for attaining a hydrogen-based economy. Fundamental research can reveal the underlying principles controlling hydrogen uptake and release by storage materials, and also aid in characterizing and designing novel storage materials. New ideas for hydrogen storage materials come from exploiting the properties of hydrophobic hydration, which refers to water s ability to stabilize, by its mode of association, specific structures under specific conditions. Although hydrogen was always considered too small to support the formation of solid clathrate hydrate structures, exciting new experiments show that water traps hydrogen molecules at conditions of low temperatures and moderate pressures. Hydrogen release is accomplished by simple warming. While these experiments lend credibility to the idea that water could form an environmentally attractive alternative storage compound for hydrogen fuel, which would advance our nation s goals of attaining a hydrogen-based economy, much work is yet required to understand and realize the full potential of clathrate hydrates for hydrogen storage. Here we undertake theoretical studies of hydrogen in water to establish a firm foundation for predictive work on clathrate hydrate H{sub 2} storage capabilities. Using molecular simulation and statistical mechanical theories based in part on quantum mechanical descriptions of molecular interactions, we characterize the interactions between hydrogen and liquid water in terms of structural and thermodynamic properties. In the process we validate classical force field models of hydrogen in water and discover new features of hydrophobic hydration that impact problems in both energy technology and biology. Finally, we predict hydrogen occupancy in the small and large cages of hydrogen clathrate hydrates, a property unresolved by previous experimental and theoretical work.

  14. Genetic influences on level and stability of self-esteem

    OpenAIRE

    Neiss, Michelle; Sedikides, Constantine; Stevenson, Jim

    2006-01-01

    We attempted to clarify the relation between self-esteem level (high vs. low) and perceived self-esteem stability (within-person variability) by using a behavioral genetics approach. We tested whether the same or independent genetic and environmental influences impact on level and stability. Adolescent twin siblings (n = 183 pairs) completed level and stability scales at two time points. Heritability for both was substantial. The remaining variance in each was attributable to non-shared envir...

  15. Biological stability of drinking water : Controlling factors, methods, and challenges

    NARCIS (Netherlands)

    Prest, E.I.E.D.; Hammes, F.; Van Loosdrecht, M.C.M.; Vrouwenvelder, J.S.

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and

  16. Stability of Drinking Water Distribution Network

    DEFF Research Database (Denmark)

    Leth, Tobias; Kallesøe, Carsten Skovmose; Sloth, Christoffer

    2016-01-01

    We strive to prove stability of a hydraulic network, where the pressure at the end user is controlled with PI control. The non-polynomial model is represented by numerous polynomial systems defined on sub-sets of R^n. The sub-sets are defined by compact basic semi-algebraic sets. The stability of...

  17. Power distribution effects on boiling water reactor stability

    International Nuclear Information System (INIS)

    Damiano, B.; March-Leuba, J.

    1989-01-01

    The work presented in this paper deals with the effects of spatial power distributions on the stability of boiling water reactors (BWRs). It is shown that a conservative power distribution exists for which the stability is minimal. These results are relevant because they imply that bounding stability calculations are possible and, thus, a worst-possible scenario may be defined for a particular BWR geometry. These bounding calculations may, then, be used to determine the maximum expected limit-cycle peak powers

  18. Population Stabilization in India: A Sub-State level Analysis

    OpenAIRE

    Purohit C, Dr Brijesh

    2007-01-01

    The study aims at analyzing economic and policy factors impinging upon population stabilization measures at the district (sub-state level) in India. It reflects upon popularly debated notions, namely, that development is the best contraceptive or whether contraceptive is the best development. In order to reflect upon this notion, we hypothesize that the factors determining the success of population stabilization measures are likely to be different across rich and poor states. It is more likel...

  19. Water: Local-Level Management

    International Development Research Centre (IDRC) Digital Library (Canada)

    Field research is examined in three approaches to local water management: small-scale water supply; wastewater treatment and reuse; and watershed management ..... That leaves issues of cost, especially for storage tanks. ..... Local response to the introduction of wastewater treatment and reuse has been largely positive.

  20. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges.

    Science.gov (United States)

    Prest, Emmanuelle I; Hammes, Frederik; van Loosdrecht, Mark C M; Vrouwenvelder, Johannes S

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  1. Biological stability of drinking water: controlling factors, methods and challenges

    Directory of Open Access Journals (Sweden)

    Emmanuelle ePrest

    2016-02-01

    Full Text Available Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g. development of opportunistic pathogens, aesthetic (e.g. deterioration of taste, odour, colour or operational (e.g. fouling or biocorrosion of pipes problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors such as (i type and concentration of available organic and inorganic nutrients, (ii type and concentration of residual disinfectant, (iii presence of predators such as protozoa and invertebrates, (iv environmental conditions such as water temperature, and (v spatial location of microorganisms (bulk water, sediment or biofilm. Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i existing knowledge on biological stability controlling factors and (ii how these factors are affected by drinking water production and distribution conditions. In addition, (iii the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discuss how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order to

  2. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    KAUST Repository

    Prest, Emmanuelle I.

    2016-02-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  3. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    Science.gov (United States)

    Prest, Emmanuelle I.; Hammes, Frederik; van Loosdrecht, Mark C. M.; Vrouwenvelder, Johannes S.

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  4. Formulation and stability of topical water in oil emulsion containing ...

    African Journals Online (AJOL)

    Purpose: To formulate the water in oil (W/O) emulsion of corn silk (CS) extract and to evaluate its stability at various storage conditions. Methods: Ethanol CS extract was prepared using maceration (cold) technique. A 4 % CS emulsion was prepared using varying concentrations of liquid paraffin, ABIL EM90 and water.

  5. Hydraulic loading, stability and water quality of Nakivubo wetland ...

    African Journals Online (AJOL)

    Nakivubo wetland, which has performed tertiary water treatment for Kampala city for the past 40 years, is ecologically stressed by agricultural and infrastructural developments. Field studies were carried out to assess the hydraulic loading, pollution profile, stability and water quality of this wetland. The upper and lower ...

  6. Trunk Stability, Trunk Strength and Sport Performance Level in Judo.

    Directory of Open Access Journals (Sweden)

    David Barbado

    Full Text Available Although trunk muscle function has been suggested to be a determinant of judo performance, its contribution to high-level performance in this sport has been poorly studied. Therefore, several tests were used to assess the differences in trunk muscle function between 11 international and 14 national level judo practitioners (judokas. Trunk strength and endurance were assessed using isokinetic tests and core stability was assessed using two protocols: 1 sudden loading, to assess trunk responses to unexpected external perturbations; 2 stable and unstable sitting, to assess the participants' ability to control trunk balance. No differences between groups were found for trunk flexor isokinetic strength, trunk responses against lateral and posterior loading and trunk control while sitting. However, international level judokas showed significantly higher trunk extensor isokinetic strength (p <0.05 and lower trunk angular displacement after anterior trunk loading (p <0.05 than national level judokas. Few and low (r < 0.512 significant correlations were found between strength, endurance and stability parameters, which suggests that trunk strength and endurance are not limiting factors for trunk stability in competitive judokas. These results support the importance of trunk extensor strength and trunk stability against forward perturbations in elite judo performance.

  7. Water and Regional Stability: The Nile a Case Study

    Science.gov (United States)

    2011-03-24

    Basin-Wide Study Final Report ( Dar es Salaam , Tanzania, May 2008), 2-1, 2-2. 30 Global Water Partnership Toolbox IWRM page, http...St ra te gy R es ea rc h Pr oj ec t WATER AND REGIONAL STABILITY: THE NILE A CASE STUDY BY LIEUTENANT COLONEL JOHN C. CURWEN United...in her remarks to Congress , eloquently described many of the reasons why the United States views water as strategically important1. The 2010 report

  8. Stabilization of zwitterionic versus canonical proline by water molecules.

    Science.gov (United States)

    Yang, Gang; Zhou, Lijun; Chen, Yang

    2016-01-01

    At physiological conditions, a majority of biomolecules (e.g., amino acids, peptides and proteins) exist predominantly in the zwitterionic form that usually decides the biological functions. However, zwitterionic amino acids are not geometrically stable in gas phase and this seriously hampers the understanding of their structures, properties and biological functions. To this end, one of the recent research focuses is to demonstrate the stabilization effects of zwitterionic amino acids. Relative stabilities of canonical conformers are dependent on water contents, while zwitterionic stability improves monotonously and pronouncedly with increase of water contents. We find that one water molecule can render zwitterionic proline geometrically stable, and stabilities of different zwitterionic amino acids increase as glycine molecules required for zwitterionic proline to be energetically preferential and conformationally predominant, respectively as four and five. Five water molecules are enough to fill up the first shell of proline functional sites (carboxylic and amido), which is in line with the results of glycine. At any water content, zwitterionic formation will not be hindered kinetically because of rather low activation barriers, and the distribution of zwitterionic amino acids will be largely dependent on their thermodynamic stabilities.

  9. A linear stability analysis of supercritical water reactors, (1). Thermal-hydraulic stability

    International Nuclear Information System (INIS)

    Tin Tin Yi; Koshizuka, Seiichi; Oka, Yoshiaki

    2004-01-01

    This paper summarizes the analysis results of the thermal-hydraulic stability of a high-temperature reactor cooled and moderated by supercritical-pressure light water (SCLWR-H). A linear stability analysis code in the frequency domain was developed to study the thermal-hydraulic stability of SCLWR-H at constant supercritical pressure. The analysis method is based on linearization by perturbation of numerically-discretized one-dimensional single-channel single-phase conservation equations. The effect of water rods on stability is considered. The thermal-hydraulic stability of SCLWR-H for full-power and partial-power normal operations was investigated by frequency domain method. Our analysis reveals that though SCLWR-H has low coolant flow rate and large density change in the core, the thermal-hydraulic stability can be maintained both at normal operation and during power raising phase of constant pressure startup by applying an orifice pressure drop coefficient an the inlet of the fuel assemblies. A parametric study was also carried out to determine the parameters affecting the stability. (author)

  10. Biological stability in drinking water distribution systems : A novel approach for systematic microbial water quality monitoring

    NARCIS (Netherlands)

    Prest, E.I.E.D.

    2015-01-01

    Challenges to achieve biological stability in drinking water distribution systems Drinking water is distributed from the treatment facility to consumers through extended man-made piping systems. The World Health Organization drinking water guidelines (2006) stated that “Water entering the

  11. Fluctuation of zonulin levels in blood vs stability of antibodies

    OpenAIRE

    Vojdani, Aristo; Vojdani, Elroy; Kharrazian, Datis

    2017-01-01

    AIM To evaluate the measurement of zonulin level and antibodies of zonulin and other tight junction proteins in the blood of controls and celiac disease patients. METHODS This study was conducted to assess the variability or stability of zonulin levels vs IgA and IgG antibodies against zonulin in blood samples from 18 controls at 0, 6, 24 and 30 h after blood draw. We also measured zonulin level as well as zonulin, occludin, vinculin, aquaporin 4 and glial fibrillary acidic protein antibodies...

  12. Charge induced stability of water droplets in subsaturated environment

    Directory of Open Access Journals (Sweden)

    J. K. Nielsen

    2011-03-01

    Full Text Available Atmospheric liquid and solid water particles are stabilized if they are coated with either negative or positive electric charge. The surface charge causes an increase of the partial pressure of water vapour close to the surface of each particle, effectively allowing the particles to remain in their condensed phase even if the environmental relative humidity drops below unity. The theory, briefly presented in this paper, predicts a zero parameter relation between surface charge density and water vapour pressure. This relation was tested in a series of Electrodynamic Balance experiments. The measurements were performed by stabilizing charged droplets of pure water near an ice-surface. We observed a divergence in radius as the temperature approached the freezing point from below. We find that the measurements confirm the theory within the experimental uncertainty. In some cases this generally overlooked effect may have impact on cloud processes and on results produced by Electrodynamic Balance experiments.

  13. Radon levels in a water distribution network

    International Nuclear Information System (INIS)

    Alabdula'aly, A.I.

    1997-01-01

    The capital city of Saudi Arabia, Riyadh, relies on both desalinated sea water as well as treated groundwater to meet all its water requirements. About 66% of the water demand is met by desalinated sea water, and the remaining is supplied by six groundwater treatment plants located in the vicinity of the city and supplied with water from 161 wells. The desalinated sea water is blended with only one plant product water and pumped to the distribution network, whereas the other five plants product water is pumped directly to the network. A study of 222 Rn levels in the city distribution network was carried out in which 89 samples were collected from different locations representing the city districts. All samples have shown low radon levels with an average concentration of 0.2 Bq l -1 and a range values of 0.1-1.0 Bq l -1 . The level of radon in different parts of the network was found to be influenced by the water sources to which they are supplied. The lowest radon levels were observed in districts supplied mostly by desalinated sea water. (Author)

  14. Process Design Concepts for Stabilization of High Level Waste Calcine

    Energy Technology Data Exchange (ETDEWEB)

    T. R. Thomas; A. K. Herbst

    2005-06-01

    The current baseline assumption is that packaging ¡§as is¡¨ and direct disposal of high level waste (HLW) calcine in a Monitored Geologic Repository will be allowed. The fall back position is to develop a stabilized waste form for the HLW calcine, that will meet repository waste acceptance criteria currently in place, in case regulatory initiatives are unsuccessful. A decision between direct disposal or a stabilization alternative is anticipated by June 2006. The purposes of this Engineering Design File (EDF) are to provide a pre-conceptual design on three low temperature processes under development for stabilization of high level waste calcine (i.e., the grout, hydroceramic grout, and iron phosphate ceramic processes) and to support a down selection among the three candidates. The key assumptions for the pre-conceptual design assessment are that a) a waste treatment plant would operate over eight years for 200 days a year, b) a design processing rate of 3.67 m3/day or 4670 kg/day of HLW calcine would be needed, and c) the performance of waste form would remove the HLW calcine from the hazardous waste category, and d) the waste form loadings would range from about 21-25 wt% calcine. The conclusions of this EDF study are that: (a) To date, the grout formulation appears to be the best candidate stabilizer among the three being tested for HLW calcine and appears to be the easiest to mix, pour, and cure. (b) Only minor differences would exist between the process steps of the grout and hydroceramic grout stabilization processes. If temperature control of the mixer at about 80„aC is required, it would add a major level of complexity to the iron phosphate stabilization process. (c) It is too early in the development program to determine which stabilizer will produce the minimum amount of stabilized waste form for the entire HLW inventory, but the volume is assumed to be within the range of 12,250 to 14,470 m3. (d) The stacked vessel height of the hot process vessels

  15. Stability of stearic acid monolayers on artificial sea water

    NARCIS (Netherlands)

    Brzozowska, A.M.; Duits, Michael H.G.; Mugele, Friedrich Gunther

    2012-01-01

    We studied the formation and stability of stearic acid (SA) based films on aqueous sub-phases via Langmuir trough and imaging ellipsometry experiments. The aqueous phase was based on Artificial Sea Water (ASW), a multicomponent salt solution with a total molarity of 0.53. The composition of this

  16. Development of a new control device for stabilizing blood level in reservoir during extracorporeal circulation.

    Science.gov (United States)

    Momose, Naoki; Yamakoshi, Rie; Kokubo, Ryo; Yasuda, Toru; Iwamoto, Norio; Umeda, Chinori; Nakajima, Itsuro; Yanagisawa, Mitsunobu; Tomizawa, Yasuko

    2010-03-01

    We developed a simple device that stabilizes the blood level in the reservoir of the extracorporeal circulation open circuit system by measuring the hydrostatic pressure of the reservoir to control the flow rate of the arterial pump. When the flow rate of the venous return decreases, the rotation speed of the arterial pump is automatically slowed down. Consequently, the blood level in the reservoir is stabilized quickly between two arbitrarily set levels and never falls below the pre-set low level. We conducted a basic experiment to verify the operation of the device, using a mock circuit with water. Commercially available pumps and reservoir were used without modification. The results confirmed that the control method effectively regulates the reservoir liquid level and is highly reliable. The device possibly also functions as a safety device.

  17. Forecasting Water Levels Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Shreenivas N. Londhe

    2011-06-01

    Full Text Available For all Ocean related activities it is necessary to predict the actual water levels as accurate as possible. The present work aims at predicting the water levels with a lead time of few hours to a day using the technique of artificial neural networks. Instead of using the previous and current values of observed water level time series directly as input and output the water level anomaly (difference between the observed water level and harmonically predicted tidal level is calculated for each hour and the ANN model is developed using this time series. The network predicted anomaly is then added to harmonic tidal level to predict the water levels. The exercise is carried out at six locations, two in The Gulf of Mexico, two in The Gulf of Maine and two in The Gulf of Alaska along the USA coastline. The ANN models performed reasonably well for all forecasting intervals at all the locations. The ANN models were also run in real time mode for a period of eight months. Considering the hurricane season in Gulf of Mexico the models were also tested particularly during hurricanes.

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

    Science.gov (United States)

    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.

  19. Stability analysis of a heated channel cooled by supercritical water

    International Nuclear Information System (INIS)

    Magni, M. C.; Delmastro, D. F; Marcel, C. P

    2009-01-01

    A simple model to study thermal-hydraulic stability of a heated cannel under supercritical conditions is presented. Single cannel stability analysis for the SCWR (Supercritical Water Cooled Reactor) design was performed. The drastic change of fluid density in the reactor core of a SCWR may induce DWO (Density Wave Oscillations) similar to those observed in BWRs. Due to the similarities between subcritical and supercritical systems we may treat the supercritical fluid as a pseudo two-phase system. Thus, we may extend the modeling approach often used for boiling flow stability analysis to supercritical pressure operation conditions. The model developed in this work take into account three regions: a heavy fluid region, similar to an incompressible liquid; a zone where a heavy fluid and a light fluid coexist, similar to two-phase mixture; and a light fluid region which behaves like superheated steam. It was used the homogeneous equilibrium model (HEM) for the pseudo boiling zone, and the ideal gas model for the pseudo superheated steam zone. System stability maps were obtained using linear stability analysis in the frequency domain. Two possible instability mechanisms are observed: DWO and excursive Ledinegg instabilities. Also, a sensitivity analysis showed that frictions in pseudo superheated steam zone, together with acceleration effect, are the most destabilizing effects. On the other hand, frictions in pseudo liquid zone are the most important stabilizing effect. [es

  20. Stability of niclosamide in water under local conditions

    International Nuclear Information System (INIS)

    El Hindi, A.M.; Sidra, M.S.

    1986-01-01

    The stability of 14 C-labelled niclosamide was studied in distilled water at two different pH values and in canal water. 2 mg/1 niclosamide solutions were exposed to direct atmospheric conditions. The activity was followed by radioassay and the concentration of niclosamide was determined by GLC. The total activity was found to decrease to 46.0% in weakly acidic solution (pH 6.5), 45% in neutral solution (pH 7.0) and 16.7% in filtered canal water after three weeks. GLC analysis showed that niclosamide concentration had dropped to 0.05, 0.06 and 0.03 mg/1 in weakly acidic, neutral medium and canal water after the same period. GLC analysis as compared to radioassay indicated the presence of increasing amounts of degradation product(s), in the chloroform extracts of water with time, which were not detected by GLC

  1. Quadratic controller syntheses for the steam generator water level

    Energy Technology Data Exchange (ETDEWEB)

    Arzelier, D.; Daafouz, J.; Bernussou, J.; Garcia, G

    1998-06-01

    The steam generator water level, (SGWL), control problem in the pressurized water reactor of a nuclear power plant is considered from robust control techniques point of view. The plant is a time-varying system with a non minimum phase behavior and an unstable open-loop response. The time-varying nature of the plant due to change in operating power is taken into account by including slowly time-varying uncertainty in the model. A linear Time-Invariant, (LTI) guaranteed cost quadratic stabilizing controller is designed in order to address some of the particular issues arising for such a control problem. (author) 17 refs.

  2. Physical and Oxidative Stability of Fish Oil-In-Water Emulsions Stabilized with Fish Protein Hydrolysates

    DEFF Research Database (Denmark)

    García Moreno, Pedro Jesús; Guadix, Antonio; Guadix, Emilia M.

    2016-01-01

    The emulsifying and antioxidant properties of fish protein hydrolysates (FPH) for the physical and oxidative stabilization of 5% (by weight) fish oil-in-water emulsions were investigated. Muscle proteins from sardine (Sardina pilchardus) and small-spotted catshark (Scyliorhinus canicula) were...... hydrolyzed to degrees of hydrolysis (DH) of 3-4-5-6% with subtilisin. Sardine hydrolysates with low DH, 3% and 4%, presented the most effective peptides to physically stabilize emulsions with smaller droplet size. This implied more protein adsorbed at the interface to act as physical barrier against......% yielded a physically stable emulsion with low concentration of unsaturated aldehydes. These results show the potential of FPH as alternative protein emulsifiers for the production of oxidatively stable fish oil-in-water emulsions....

  3. Dynamic Stabilization of Metal Oxide–Water Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    McBriarty, Martin E.; von Rudorff, Guido Falk; Stubbs, Joanne E.; Eng, Peter J.; Blumberger, Jochen; Rosso, Kevin M.

    2017-02-08

    The interaction of water with metal oxide surfaces plays a crucial role in the catalytic and geochemical behavior of metal oxides. In a vast majority of studies, the interfacial structure is assumed to arise from a relatively static lowest energy configuration of atoms, even at room temperature. Using hematite (α-Fe2O3) as a model oxide, we show through a direct comparison of in situ synchrotron X-ray scattering with density functional theory-based molecular dynamics simulations that the structure of the (1102) termination is dynamically stabilized by picosecond water exchange. Simulations show frequent exchanges between terminal aquo groups and adsorbed water in locations and with partial residence times consistent with experimentally determined atomic sites and fractional occupancies. Frequent water exchange occurs even for an ultrathin adsorbed water film persisting on the surface under a dry atmosphere. The resulting time-averaged interfacial structure consists of a ridged lateral arrangement of adsorbed water molecules hydrogen bonded to terminal aquo groups. Surface pKa prediction based on bond valence analysis suggests that water exchange will influence the proton-transfer reactions underlying the acid/base reactivity at the interface. Our findings provide important new insights for understanding complex interfacial chemical processes at metal oxide–water interfaces.

  4. Water-level fluctuations influence sediment porewater ...

    Science.gov (United States)

    Reservoirs typically have elevated fish mercury (Hg) levels compared to natural lakes and rivers. A unique feature of reservoirs is water-level management which can result in sediment exposure to the air. The objective of this study is to identify how reservoir water-level fluctuations impact Hg cycling, particularly the formation of the more toxic and bioaccumulative methylmercury (MeHg). Total-Hg (THg), MeHg, stable isotope methylation rates and several ancillary parameters were measured in reservoir sediments (including some in porewater and overlying water) that are seasonally and permanently inundated. The results showed that sediment and porewater MeHg concentrations were over 3-times higher in areas experiencing water-level fluctuations compared to permanently inundated sediments. Analysis of the data suggest that the enhanced breakdown of organic matter in sediments experiencing water-level fluctuations has a two-fold effect on stimulating Hg methylation: 1) it increases the partitioning of inorganic Hg from the solid phase into the porewater phase (lower log Kd values) where it is more bioavailable for methylation; and 2) it increases dissolved organic carbon (DOC) in the porewater which can stimulate the microbial community that can methylate Hg. Sulfate concentrations and cycling were enhanced in the seasonally inundated sediments and may have also contributed to increased MeHg production. Overall, our results suggest that reservoir management a

  5. Fluctuation of zonulin levels in blood vs stability of antibodies.

    Science.gov (United States)

    Vojdani, Aristo; Vojdani, Elroy; Kharrazian, Datis

    2017-08-21

    To evaluate the measurement of zonulin level and antibodies of zonulin and other tight junction proteins in the blood of controls and celiac disease patients. This study was conducted to assess the variability or stability of zonulin levels vs IgA and IgG antibodies against zonulin in blood samples from 18 controls at 0, 6, 24 and 30 h after blood draw. We also measured zonulin level as well as zonulin, occludin, vinculin, aquaporin 4 and glial fibrillary acidic protein antibodies in the sera of 30 patients with celiac disease and 30 controls using enzyme-linked immunosorbent assay methodology. The serum zonulin level in 6 out of 18 subjects was low or zonulin levels of > 2.8 ng/mL and showed significant fluctuation from sample to sample. Comparatively, zonulin antibody measured in all samples was highly stable and reproducible from sample to sample. Celiac disease patients showed zonulin levels with a mean of 8.5 ng/mL compared to 3.7 ng/mL in controls ( P zonulin level at 2SD above the mean was demonstrated in 37% of celiac disease patients, while antibodies against zonulin, occludin and other tight junction proteins was detected in up to 86% of patients with celiac disease. Due to its fluctuation, a single measurement of zonulin level is not recommended for assessment of intestinal barrier integrity. Measurement of IgG and IgA antibodies against zonulin, occludin, and other tight junction proteins is proposed for the evaluation of the loss of intestinal barrier integrity.

  6. Investigation on flow stability of supercritical water cooled systems

    International Nuclear Information System (INIS)

    Cheng, X.; Kuang, B.

    2006-01-01

    Research activities are ongoing worldwide to develop nuclear power plants with supercritical water cooled reactor (SCWR) with the purpose to achieve a high thermal efficiency and to improve their economical competitiveness. However, the strong variation of the thermal-physical properties of water in the vicinity of the pseudo-critical line results in challenging tasks in various fields, e.g. thermal-hydraulic design of a SCWR. One of the challenging tasks is to understand and to predict the dynamic behavior of supercritical water cooled systems. Although many thermal-hydraulic research activities were carried out worldwide in the past as well as in the near present, studies on dynamic behavior and flow stability of SC water cooled systems are scare. Due to the strong density variation, flow stability is expected to be one of the key items which need to be taken into account in the design of a SCWR. In the present work, the dynamic behavior and flow stability of SC water cooled systems are investigated using both numerical and theoretical approaches. For this purpose a new computer code SASC was developed, which can be applied to analysis the dynamic behavior of systems cooled by supercritical fluids. In addition, based on the assumptions of a simplified system, a theoretical model was derived for the prediction of the onset of flow instability. A comparison was made between the results obtained using the theoretical model and those from the SASC code. A good agreement was achieved. This gives the first evidence of the reliability of both the SASC code and the theoretical model

  7. Radiolytic stability of gibbsite and boehmite with adsorbed water

    Science.gov (United States)

    Huestis, Patricia; Pearce, Carolyn I.; Zhang, X.; N'Diaye, Alpha T.; Rosso, Kevin M.; LaVerne, Jay A.

    2018-04-01

    Aluminum oxyhydroxide (boehmite, AlOOH) and aluminum hydroxide (gibbsite, Al(OH)3) powders with adsorbed water were irradiated with γ-rays and 5 MeV He ions (α-particles) in order to determine overall radiation stability and chemical modification to the surface. No variation in overall phase or crystallinity due to radiolysis was observed with X-ray diffraction (XRD) and Raman spectroscopy for doses up to 2 MGy with γ-rays and 175 MGy with α-particles. Temperature programed desorption (TPD) of the water from the surface to the gas phase indicated that the water was chemisorbed and strongly bound. Water adsorption sites are of similar energy for both gibbsite and boehmite. Observation of the water adsorbed on the surface of gibbsite and boehmite with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) showed broad peaks at 3100-3600 cm-1 due to OH stretching that slowly decreased on heating to 500 °C, which corresponds well with the water vapor evolution observed with TPD. Both materials were found to be amorphous following heating to 500 °C. X-ray photoelectron spectroscopy (XPS) indicated surface reduction of Al(III) to Al metal on radiolysis with α-particles. Complete loss of chemisorbed water and the formation of bulk O atoms was observed following radiolysis with α-particles.

  8. Radiolytic stability of gibbsite and boehmite with adsorbed water

    Energy Technology Data Exchange (ETDEWEB)

    Huestis, Patricia; Pearce, Carolyn I.; Zhang, X.; N' Diaye, Alpha T.; Rosso, Kevin M.; LaVerne, Jay A.

    2018-04-01

    Aluminum oxyhydroxide (boehmite, AlOOH) and aluminum hydroxide (gibbsite, Al(OH)3) powders with adsorbed water were irradiated with -rays and 5 MeV He ions (α-particles) in order to determine overall radiation stability and chemical modification to the surface. No variation in overall phase or crystallinity due to radiolysis was observed with X-ray diffraction (XRD) and Raman spectroscopy for doses up to 2 MGy with -rays and 175 MGy with α-particles. Temperature programed desorption (TPD) of the water from the surface to the gas phase indicated that the water was chemisorbed and strongly bound. Water adsorption sites are of similar energy for both gibbsite and boehmite. Observation of the water adsorbed on the surface of gibbsite and boehmite with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) showed broad peaks at 3100-3600 cm-1 due to OH stretching that slowly decreased on heating to 500oC, which corresponds well with the water vapor evolution observed with TPD. Both materials were found to be amorphous following heating to 500oC. X-ray photoelectron spectroscopy (XPS) indicated surface reduction of Al(III) to Al metal on radiolysis with α-particles. Complete loss of chemisorbed water and the formation of bulk O atoms was observed following radiolysis with α-particles.

  9. Stability of amorphous silica-alumina in hot liquid water.

    Science.gov (United States)

    Hahn, Maximilian W; Copeland, John R; van Pelt, Adam H; Sievers, Carsten

    2013-12-01

    Herein, the hydrothermal stability of amorphous silica-alumina (ASA) is investigated under conditions relevant for the catalytic conversion of biomass, namely in liquid water at 200 °C. The hydrothermal stability of ASA is much higher than that of pure silica or alumina. Interestingly, the synthetic procedure used plays a major role in its resultant stability: ASA prepared by cogelation (CG) lost its microporous structure, owing to hydrolysis of the siloxane bonds, but the resulting mesoporous material still had a considerable surface area. ASA prepared by deposition precipitation (DP) contained a silicon-rich core and an aluminum-rich shell. In hot liquid water, the latter structure was transformed into a layer of amorphous boehmite, which protected the particle from further hydrolysis. The surface area showed relatively minor changes during the transformation. Independent of the synthetic method used, the ASAs retained a considerable concentration of acid sites. The concentration of acid sites qualitatively followed the changes in surface area, but the changes were less pronounced. The performance of different ASAs for the hydrolysis of cellobiose into glucose is compared. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Vortex Stability In Two -layer Rotating Shallow-water Flows

    Science.gov (United States)

    Carton, Xavier; Baey, Jean-Michel

    The stability of circular vortices subject to an initial normal-mode perturbation is studied in a two-layer shallow-water fluid with rigid lid, flat bottom and constant background rotation. Considerable similarity with quasi-geostrophic dynamics is found for linear (barotropic or baroclinic) instability, except in the frontal and nonlinear barotropic limits. This discrepancy is explained by asymptotic models. In many cases, the elliptical mode of deformation is the most unstable one. The ability of these perturbed circular vortices to stabilize nonlinearly as long-lived multipoles is then investigated. For elliptical perturbations, steady tripoles form from moderately unstable vortices as in the quasi-geostrophic limit. These tripoles, which exhibit various 3D structures, are robust when perturbed by non coherent disturbances. More unstable circular vortices break as two dipoles, propagating in opposite directions. Triangular perturbations can also lead to stationary quadrupoles or to dipolar breaking. The similarity with quasi-geostrophic dynamics, which ext ends to these nonlinear regimes, is related to the weakness of the divergent circulation, as shown by the analysis of the Lighthill equation. J.M. Baey &X. Carton, 2001: "Piecewise-constant vortices in a two-layer shallow - water flow". Advances in mathematical modelling of atmosphere and ocean dynamics, Kluwer Acad. Publ., 61, p.87-92. J.M. Baey &X. Carton, 2002: "Vortex multipoles in two-layer rotating shallow -water flows". To appear in J. Fluid Mech.

  11. A improved tidal method without water level

    Science.gov (United States)

    Luo, xiaowen

    2017-04-01

    Now most tide are obtained use water Level and pressure type water gage, but it is difficult to install them and reading is in low accuracy in this method . In view of above-mentioned facts, In order to improve tide accuracy, A improved method is introduced.sea level is obtained in given time using high-precision GNSS buoy combined instantaneous position from pressure gage. two steps are as following, (1) the GNSS time service is used as the source of synchronization reference in tidal measurement; (2) centimeter-level sea surface positions are obtained in real time using difference GNSS The improved method used in seafloor topography survey,in 145 cross points, 95% meet the requirements of the Hydrographic survey specification. It is effective method to obtain higher accuracy tide.

  12. Stability analysis of the high performance light water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Gomez, Tino

    2009-03-15

    In the Generation IV international advanced nuclear reactor development program, the High Performance Light Water Reactor (HPLWR) is one of the most promising candidates. Important features are its inherently high thermodynamic efficiency (of approximately 45 %) and the ability to use existing supercritical water technology which previously has been developed and deployed for fossil fired power plants. Within a HPLWR core, the fluid experiences a drastic change in thermal and transport properties such as density, dynamic viscosity, specific heat and thermal conductivity, as the supercritical water is heated from 280 C to 500 C. The density change substantially exceeds that in a Boiling Water Reactor (i.e., HPLWR: density changes from 780 kg/m{sup 3} to 90 kg/m{sup 3}; BWR: density changes from 750 kg/m{sup 3} to 198 kg/m3). Due to this density change, the HPLWR can be - under certain operation parameters - susceptible to various thermal-hydraulic flow instabilities, which have to be avoided. In this thesis a stability analysis for the HPLWR is presented. This analysis is based on analytical considerations and numerical results, which were obtained by a computer code developed by the author. The heat-up stages of the HPLWR three-pass core are identified in respect to the relevant flow instability phenomena. The modeling approach successfully used for BWR stability analysis is extended to supercritical pressure operation conditions. In particular, a one-dimensional equation set representing the coolant flow of HPLWR fuel assemblies has been implemented in a commercial software named COMSOL to perform steady-state, time-dependent, and modal analyses. An investigation of important static instabilities (i.e., Ledinegg instabilities, flow maldistribution) and Pressure Drop Oscillations (PDO) have been carried out and none were found under operation conditions of the HPLWR. Three types of Density Wave Oscillation (DWO) modes have been studied: the single channel DWO, the

  13. Feasibility of suspension spraying of yttria-stabilized zirconia with water-stabilized plasma torch

    Czech Academy of Sciences Publication Activity Database

    Mušálek, Radek; Bertolissi, Gabriele; Medřický, J.; Kotlan, Jiří; Pala, Zdeněk; Curry, N.

    2015-01-01

    Roč. 268, April (2015), s. 58-62 ISSN 0257-8972. [Rencontres Internationales de la Projection Thermique/6./. Limoges, 11.12.2013-13.12.2013] R&D Projects: GA ČR(CZ) GPP108/12/P552 Institutional support: RVO:61389021 Keywords : Thermal spray coating * Suspension spraying * Thermal barrier coating * Water-stabilized plasma * High enthalpy plasma Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 2.139, year: 2015 http://www.sciencedirect.com/science/article/pii/S025789721400680X

  14. Soil water retention and structure stability as affected by water quality

    Directory of Open Access Journals (Sweden)

    Amrakh I. Mamedov

    2014-04-01

    Full Text Available In arid and semi-arid zones with a short water resources studying the effects of water quality on soil water retention and structure is important for the development of effective soil and water conservation and management practices. Three water qualities (electrical conductivity, EC ~ 2, 100 and 500 μS cm-1 with a low SAR representing rain, canal-runoff and irrigation water respectively and semi-arid loam and clay soils were tested to evaluate an effect of soil texture and water quality on water retention, and aggregate and structure stability using the high energy moisture characteristic (HEMC method. The water retention curves obtained by the HEMC method were characterized by the modified van Genuchten (1980 model that provides (i model parameters α and n, which represent the location (of the inflection point and the steepness of the S-shaped water retention curve respectively, and (ii a volume of drainable pores (VDP, which is an indicator for the quantity of water released by the tested sample over the range of suction studied, and modal suction (MS, which corresponds to the most frequent pore sizes, and soil structure index, SI =VDP/MS. Generally (i treatments significantly affected the shape of the water retention curves (α and n and (ii contribution of soil type, water EC, and wetting rate and their interaction had considerable effect on the stability induces and model parameters. Most of changes due to the water quality and wetting condition were in the range of matric potential (ψ, 1.2-2.4; and 2.4-5.0 J kg-1 (pore size 125-250 μm and 60-125 μm. The VDP, SI and α increased, and MS and n decreased with the increase in clay content, water EC and the decrease in rate of aggregate wetting. The SI increased exponentially with the increase in VDP, and with the decrease in MS. Contribution of water EC on stability indices and model parameters was not linear and was soil dependent, and could be more valuable at medium water EC. Effect of

  15. Stability analysis on natural circulation boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Metz, Peter

    1999-05-01

    The purpose of the study is a stability analysis of the simplified boiling water reactor concept. A fluid dynamics code, DYNOS, was developed and successfully validated against FRIGG and DESIRE data and a stability benchmark on the Ringhals 1 forced circulation BWR. Three simplified desings were considered in the analysis: The SWRIOOO by Siemens and the SBWR and ESBWR from the General Electric Co. For all three design operational characteristics, i.e. power versus flow rate maps, were calculated. The effects which different geometric and operational parameters, such as the riser height, inlet subcooling etc., have on the characteristics have been investigated. Dynamic simulations on the three simplified design revealed the geysering and the natural circulation oscillations modes only. They were, however, only encountered at pressure below 0.6 MPa. Stability maps for all tree simplified BWRs were calculated and plotted. The study concluded that a fast pressurisation of the reactor vessel is necessary to eliminate the possibility of geysering or natural circulation oscillations mode instability. (au) 26 tabs., 88 ills.

  16. Water-driven stabilization of cadmium sulphide nanoparticles

    Science.gov (United States)

    Goswami, Navendu; Sen, P.

    2017-12-01

    Water driven stabilization of cadmium sulphide (CdS) nanoparticles, synthesized through a novel and facile electro-explosion of wire (EEW) technique, is reported by us. The transformation of prepared material was visually evident; as greenish black colour of the colloidal as well as the powder particles, obtained just after the synthesis, changed to orange colour after one month. Cubic Hawleyite phase CdS nanoparticles with 2.3-13.4 nm average crystallite size were ascertained by XRD analysis. HRTEM and AFM analysis collectively confirmed the formation of stable CdS nanoparticles. The crucial S-H vibrational mode, a signature interaction of CdS nanoparticles with surrounding water molecules, was revealed by FTIR analysis. The composition of prepared nanoparticles was accessed through XPS analysis. Not only structural but optical properties of nanoparticles also altered due to aging of nanoparticles. Enhanced band gap of CdS nanoparticles and gradual prominence of absorption energy with aging were demonstrated through UV-vis analysis. Complementary to this, PL spectroscopic analysis revealed the photophysics of CdS nanoparticles by providing details of radiative recombination channels. Thus, intricacies of CdS nanoparticles stabilization in aqueous environment were unravelled on the basis of variations in crystallinity, local chemical environment, alterations in electronic structure and optical processes occurring therein.

  17. Stabilized oil production conditions in the development equilibrium of a water-flooding reservoir

    Directory of Open Access Journals (Sweden)

    Renshi Nie

    2016-12-01

    Full Text Available Water injection can compensate for pressure depletion of production. This paper firstly investigated into the equilibrium issue among water influx, water injection and production. Equilibrium principle was elaborated through deduction of equilibrium equation and presentation of equilibrium curves with an “equilibrium point”. Influences of artificial controllable factors (e.g. well ratio of injection to production and total well number on equilibrium were particularly analyzed using field data. It was found that the influences were mainly reflected as the location move of equilibrium point with factor change. Then reservoir pressure maintenance level was especially introduced to reveal the variation law of liquid rate and oil rate with the rising of water cut. It was also found that, even if reservoir pressure kept constant, oil rate still inevitably declined. However, in the field, a stabilized oil rate was always pursued for development efficiency. Therefore, the equilibrium issue of stabilized oil production was studied deeply through probing into some effective measures to realize oil rate stability after the increase of water cut for the example reservoir. Successful example application indicated that the integrated approach was very practical and feasible, and hence could be used to the other similar reservoir.

  18. Dynamic Stabilization of Metal Oxide–Water Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    McBriarty, Martin E.; von Rudorff, Guido Falk; Stubbs, Joanne; Eng, Peter; Blumberger, Jochen; Rosso, Kevin M.

    2017-02-08

    Metal oxide growth, dissolution, and redox reactivity depend on the structure and dynamics at the interface with aqueous solution. We present the most definitive analysis to date of the hydrated naturally abundant r-cut (11$\\bar{0}$2) termination of the iron oxide hematite (α-Fe2O3). In situ synchrotron X-ray scattering analysis reveals a ridged lateral arrangement of adsorbed water molecules hydrogen bonded to terminal aquo groups. Large-scale hybrid-functional density functional theory-based molecular dynamics (DFT-MD) simulations show how this structure is dynamically stabilized by picosecond exchange between aquo groups and adsorbed water, even under nominally dry conditions. Surface pKa prediction based on bond valence analysis suggests that water exchange may influence the proton transfer reactions associated with acid/base reactivity at the interface. Our findings rectify inconsistencies between existing models and may be extended to resolving more complex electrochemical phenomena at metal oxide-water interfaces.

  19. GNSS-Reflectometry based water level monitoring

    Science.gov (United States)

    Beckheinrich, Jamila; Schön, Steffen; Beyerle, Georg; Apel, Heiko; Semmling, Maximilian; Wickert, Jens

    2013-04-01

    Due to climate changing conditions severe changes in the Mekong delta in Vietnam have been recorded in the last years. The goal of the German Vietnamese WISDOM (Water-related Information system for the Sustainable Development Of the Mekong Delta) project is to build an information system to support and assist the decision makers, planners and authorities for an optimized water and land management. One of WISDOM's tasks is the flood monitoring of the Mekong delta. Earth reflected L-band signals from the Global Navigation Satellite System show a high reflectivity on water and ice surfaces or on wet soil so that GNSS-Reflectometry (GNSS-R) could contribute to monitor the water level in the main streams of the Mekong delta complementary to already existing monitoring networks. In principle, two different GNSS-R methods exist: the code- and the phase-based one. As the latter being more accurate, a new generation of GORS (GNSS Occultation, Reflectometry and Scatterometry) JAVAD DELTA GNSS receiver has been developed with the aim to extract precise phase observations. In a two week lasting measurement campaign, the receiver has been tested and several reflection events at the 150-200 m wide Can Tho river in Vietnam have been recorded. To analyze the geometrical impact on the quantity and quality of the reflection traces two different antennas height were tested. To track separately the direct and the reflected signal, two antennas were used. To derive an average height of the water level, for a 15 min observation interval, a phase model has been developed. Combined with the coherent observations, the minimum slope has been calculated based on the Least- Squares method. As cycle slips and outliers will impair the results, a preprocessing of the data has been performed. A cycle slip detection strategy that allows for automatic detection, identification and correction is proposed. To identify outliers, the data snooping method developed by Baarda 1968 is used. In this

  20. Estimating Water Levels with Google Earth Engine

    Science.gov (United States)

    Lucero, E.; Russo, T. A.; Zentner, M.; May, J.; Nguy-Robertson, A. L.

    2016-12-01

    Reservoirs serve multiple functions and are vital for storage, electricity generation, and flood control. For many areas, traditional ground-based reservoir measurements may not be available or data dissemination may be problematic. Consistent monitoring of reservoir levels in data-poor areas can be achieved through remote sensing, providing information to researchers and the international community. Estimates of trends and relative reservoir volume can be used to identify water supply vulnerability, anticipate low power generation, and predict flood risk. Image processing with automated cloud computing provides opportunities to study multiple geographic areas in near real-time. We demonstrate the prediction capability of a cloud environment for identifying water trends at reservoirs in the US, and then apply the method to data-poor areas in North Korea, Iran, Azerbaijan, Zambia, and India. The Google Earth Engine cloud platform hosts remote sensing data and can be used to automate reservoir level estimation with multispectral imagery. We combine automated cloud-based analysis from Landsat image classification to identify reservoir surface area trends and radar altimetry to identify reservoir level trends. The study estimates water level trends using three years of data from four domestic reservoirs to validate the remote sensing method, and five foreign reservoirs to demonstrate the method application. We report correlations between ground-based reservoir level measurements in the US and our remote sensing methods, and correlations between the cloud analysis and altimetry data for reservoirs in data-poor areas. The availability of regular satellite imagery and an automated, near real-time application method provides the necessary datasets for further temporal analysis, reservoir modeling, and flood forecasting. All statements of fact, analysis, or opinion are those of the author and do not reflect the official policy or position of the Department of Defense or any

  1. Hydrostatic Water Level Systems At Homestake DUSEL

    Science.gov (United States)

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

    2009-12-01

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

  2. Surf Zone Hydrodynamics and its Utilization in Biotechnical Stabilization of Water Reservoir Banks

    Directory of Open Access Journals (Sweden)

    Petr Pelikán

    2014-01-01

    Full Text Available The water reservoir banks are eroded mainly by two factors. The first one is wave action (i.e. wave abrasion affecting the bank in direction from the reservoir. The second one is the influence of water flowing downward over the bank surface in direction from land into the reservoir (e.g. rainfall. The determination of regular altitudinal emplacement of proper designed particular biotechnical stabilization elements is the most important factor on which the right functionality of whole construction depends. Surf zone hydrodynamics solves the wave and water level changes inside the region extending from the wave breaking point to the limit of wave up-rush. The paper is focused on the utilization of piece of knowledge from a part of sea coast hydrodynamics and new approach in its application in the conditions of inland water bodies when designing the biotechnical stabilization elements along the shorelines. The “reinforced grass carpets” as a type of biotechnical method of bank stabilization are presented in the paper; whether the growth of grass root system is dependent on presence or absence of geomats in the soil structure and proceeding of their establishment on the shorelines.

  3. N-type organic electrochemical transistors with stability in water

    KAUST Repository

    Giovannitti, Alexander

    2016-10-07

    Organic electrochemical transistors (OECTs) are receiving significant attention due to their ability to efficiently transduce biological signals. A major limitation of this technology is that only p-type materials have been reported, which precludes the development of complementary circuits, and limits sensor technologies. Here, we report the first ever n-type OECT, with relatively balanced ambipolar charge transport characteristics based on a polymer that supports both hole and electron transport along its backbone when doped through an aqueous electrolyte and in the presence of oxygen. This new semiconducting polymer is designed specifically to facilitate ion transport and promote electrochemical doping. Stability measurements in water show no degradation when tested for 2 h under continuous cycling. This demonstration opens the possibility to develop complementary circuits based on OECTs and to improve the sophistication of bioelectronic devices.

  4. Sterically stabilized water based magnetic fluids: Synthesis, structure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Bica, Doina [Laboratory of Magnetic Fluids, Center for Fundamental and Advanced Technical Research, Romanian Academy, Timisoara Division, Bd. Mihai Viteazul 24, 300223 Timisoara (Romania); Vekas, Ladislau [Laboratory of Magnetic Fluids, Center for Fundamental and Advanced Technical Research, Romanian Academy, Timisoara Division, Bd. Mihai Viteazul 24, 300223 Timisoara (Romania) and National Centre for Engineering of Systems with Complex Fluids, University Politehnica Timisoara, Bd. Mihai Viteazul 1, 300222 Timisoara (Romania)]. E-mail: vekas@acad-tim.tm.edu.ro; Avdeev, Mikhail V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Marinica, Oana [National Centre for Engineering of Systems with Complex Fluids, University Politehnica Timisoara, Bd. Mihai Viteazul 1, 300222 Timisoara (Romania); Socoliuc, Vlad [National Institute R and D for Electrochemistry and Condensed Matter, Str. Diaconu Coressi 144, 300588 Timisoara (Romania); Balasoiu, Maria [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Garamus, Vasil M. [GKSS Research Centre, Geesthacht (Germany)

    2007-04-15

    Magnetic fluids (MFs), prepared by chemical co-precipitation followed by double layer steric and electrostatic (combined) stabilization of magnetite nanoparticles dispersed in water, are presented. Several combinations of surfactants with different chain lengths (lauric acid (LA), myristic acid (MA), oleic acid (OA) and dodecyl-benzene-sulphonic acid (DBS)) were used, such as LA+LA, MA+MA, LA+DBS, MA+DBS, OA+DBS, OA+OA and DBS+DBS. Static light scattering, transmission electron microscopy, small angle neutron scattering, magnetic and magneto-rheological measurements revealed that MFs with MA+MA or LA+LA biocompatible double layer covered magnetite nanoparticles are the most stable colloidal systems among the investigated samples, and thus suitable for biomedical applications.

  5. Formation and stability of cubic ice in water droplets.

    Science.gov (United States)

    Murray, Benjamin J; Bertram, Allan K

    2006-01-07

    There is growing evidence that a metastable phase of ice, cubic ice, plays an important role in the Earth's troposphere and stratosphere. Cubic ice may also be important in diverse fields such as cryobiology and planetary sciences. Using X-ray diffraction, we studied the formation of cubic ice in pure water droplets suspended in an oil matrix as a function of droplet size. The results show that droplets of volume median diameter 5.6 microm froze dominantly to cubic ice with stacking faults. These results support previous suggestions that cubic ice is the crystalline phase that nucleates when pure water droplets freeze homogeneously at approximately 235 K. It is also shown that as the size of the water droplets increased from 5.6 to 17.0 microm, the formation of the stable phase of ice, hexagonal ice, was favoured. This size dependence can be rationalised with heat transfer calculations. We also investigated the stability of cubic ice that forms in water droplets suspended in an oil matrix. We observe cubic ice up to 243 K, much higher in temperature than observed in many previous studies. This result adds to the existing literature that shows bulk ice I(c) can persist up to approximately 240 K. The transformation of cubic ice to hexagonal ice also showed a complex time and temperature dependence, proceeding rapidly at first and then slowing down and coming to a halt. These combined results help explain why cubic ice forms in some experiments described in the literature and not others.

  6. Models and Stability Analysis of Boiling Water Reactors

    International Nuclear Information System (INIS)

    Dorning, John

    2002-01-01

    We have studied the nuclear-coupled thermal-hydraulic stability of boiling water reactors (BWRs) using a model that includes: space-time modal neutron kinetics based on spatial w-modes; single- and two-phase flow in parallel boiling channels; fuel rod heat conduction dynamics; and a simple model of the recirculation loop. The BR model is represented by a set of time-dependent nonlinear ordinary differential equations, and is studied as a dynamical system using the modern bifurcation theory and nonlinear dynamical systems analysis. We first determine the stability boundary (SB) - or Hopf bifurcation set- in the most relevant parameter plane, the inlet-subcooling-number/external-pressure-drop plane, for a fixed control rod induced external reactivity equal to the 100% rod line value; then we transform the SB to the practical power-flow map used by BWR operating engineers and regulatory agencies. Using this SB, we show that the normal operating point at 100% power is very stable, that stability of points on the 100% rod line decreases as the flow rate is reduced, and that operating points in the low-flow/high-power region are least stable. We also determine the SB that results when the modal kinetics is replaced by simple point reactor kinetics, and we thereby show that the first harmonic mode does not have a significant effect on the SB. However, we later show that it nevertheless has a significant effect on stability because it affects the basin of attraction of stable operating points. Using numerical simulations we show that, in the important low-flow/high-power region, the Hopf bifurcation that occurs as the SB is crossed is subcritical; hence, growing oscillations can result following small finite perturbations of stable steady-states on the 100% rod line at points in the low-flow/high-power region. Numerical simulations are also performed to calculate the decay ratios (DRs) and frequencies of oscillations for various points on the 100% rod line. It is

  7. Models and Stability Analysis of Boiling Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    John Dorning

    2002-04-15

    We have studied the nuclear-coupled thermal-hydraulic stability of boiling water reactors (BWRs) using a model that includes: space-time modal neutron kinetics based on spatial w-modes; single- and two-phase flow in parallel boiling channels; fuel rod heat conduction dynamics; and a simple model of the recirculation loop. The BR model is represented by a set of time-dependent nonlinear ordinary differential equations, and is studied as a dynamical system using the modern bifurcation theory and nonlinear dynamical systems analysis. We first determine the stability boundary (SB) - or Hopf bifurcation set- in the most relevant parameter plane, the inlet-subcooling-number/external-pressure-drop plane, for a fixed control rod induced external reactivity equal to the 100% rod line value; then we transform the SB to the practical power-flow map used by BWR operating engineers and regulatory agencies. Using this SB, we show that the normal operating point at 100% power is very stable, that stability of points on the 100% rod line decreases as the flow rate is reduced, and that operating points in the low-flow/high-power region are least stable. We also determine the SB that results when the modal kinetics is replaced by simple point reactor kinetics, and we thereby show that the first harmonic mode does not have a significant effect on the SB. However, we later show that it nevertheless has a significant effect on stability because it affects the basin of attraction of stable operating points. Using numerical simulations we show that, in the important low-flow/high-power region, the Hopf bifurcation that occurs as the SB is crossed is subcritical; hence, growing oscillations can result following small finite perturbations of stable steady-states on the 100% rod line at points in the low-flow/high-power region. Numerical simulations are also performed to calculate the decay ratios (DRs) and frequencies of oscillations for various points on the 100% rod line. It is

  8. Effects of process conditions on chlorine generation and storage stability of electrolyzed deep ocean water.

    Science.gov (United States)

    Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

    2015-12-01

    Electrolyzed water is a sustainable disinfectant, which can comply with food safety regulations and is environmentally friendly. We investigated the effects of platinum plating of electrode, electrode size, cell potential, and additional stirring on electrolysis properties of deep ocean water (DOW) and DOW concentration products. We also studied the relationships between quality properties of electrolyzed DOW and their storage stability. Results indicated that concentrating DOW to 1.7 times increased chlorine level in the electrolyzed DOW without affecting electric and current efficiencies of the electrolysis process. Increasing magnesium and potassium levels in DOW decreased chlorine level in the electrolyzed DOW as well as electric and current efficiencies of the electrolysis process. Additional stirring could not increase electrolysis efficiency of small electrolyzer. Large electrode, high electric potential and/or small electrolyzing cell increased chlorine production rate but decreased electric and current efficiencies. High electrolysis intensity decreased storage stability of the electrolyzed seawater and the effects of electrolysis on DOW gradually subsided in storage. DOW has similar electrolysis properties to surface seawater, but its purity and stability are better. Therefore, electrolyzed DOW should have better potential for applications on postharvest cleaning and disinfection of ready-to-eat fresh produce. Copyright © 2015. Published by Elsevier B.V.

  9. Interferometric system for PM-level stability characterization

    NARCIS (Netherlands)

    Verlaan, A.L.; Ellis, J.D.; Voigt, D.; Spronck, J.W.; Munnig Schmidt, R.H.

    2010-01-01

    We present a double sided, single pass Michelson heterodyne interferometer for dimensional stability measurements. In preliminary measurements, the double deadpath configuration (no sample) showed better than ±1.5 nm (2/) over 13 hours. A 30 mm stainless gauge block was then measured with a

  10. Predicting Water Levels at Kainji Dam Using Artificial Neural Networks

    African Journals Online (AJOL)

    The aim of this study is to develop artificial neural network models for predicting water levels at Kainji Dam, which supplies water to Nigeria's largest hydropower generation station. It involves taking of a ten-year record of the daily water levels at the dam from 2001 to 2010. The daily water level data were used to develop ...

  11. Drinking Water Maximum Contaminant Levels (MCLs)

    Data.gov (United States)

    U.S. Environmental Protection Agency — National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards...

  12. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  13. Geographical mapping of fluoride levels in drinking water sources in ...

    African Journals Online (AJOL)

    Background: Knowledge of fluoride levels in drinking water is of importance in dental public health, yet this information is lacking, at national level, in Nigeria. Objective: To map out fluoride levels in drinking water sources in Nigeria. Materials and Methods: Fluoride levels in drinking water sources from 109 randomly ...

  14. Operational Principle of Water Level Detector for Agricultural and ...

    African Journals Online (AJOL)

    This paper proposes a design to automatically detect the level of water in a reservoir (storage tank) at a preset level and initializes an information to the users in case of low water level. The functionality of this sensor depends basically on the electrical conductivity of water (probes) which varies, depending on the level of its ...

  15. Experimental research of "microcable in a microconduct" system stability to effect of freezing water

    Science.gov (United States)

    Andreev, Vladimir A.; Burdin, Vladimir A.; Nikulina, Tatiana G.; Alekhin, Ivan N.; Gavryushin, Sergey A.; Nikulin, Aleksey G.; Praporshchikov, Denis E.

    2011-12-01

    Results of experimental researches of "optical microcable in a microduct" system stability to effect of freezing water are presented. It is shown this system is steadier to water freezing in comparison to lighten optical cable in protective polymer tube.

  16. Impact of Rain Water Infiltration on the Stability of Earth Slopes

    Directory of Open Access Journals (Sweden)

    Muhammad Farooq Ahmed

    2016-12-01

    Full Text Available Slope failure occurs very often in natural and man-made slopes which are subjected to frequent changes in ground water level, rapid drawdown, rainfall and earthquakes. The current study discusses the significance of water infiltration, pore water pressure and degree of saturation that affect the stability of earth slopes. Rainwater infiltration not only mechanically reduces the shear strength of a slope material, but also chemically alters the mineral composition of the soil matrix. It results in the alteration of macro structures which in turn decreases the factor of safety. A few case studies are discussed in this paper to quantitatively observe the variation in factor of safety (FOS of various earth slopes by changing the degree of saturation. The results showed that most of the earth slopes get failed or become critical when the degree of saturation approaches to 50 % or more.

  17. Array-level stability enhancement of 50 nm AlxOy ReRAM

    Science.gov (United States)

    Iwasaki, Tomoko Ogura; Ning, Sheyang; Yamazawa, Hiroki; Takeuchi, Ken

    2015-12-01

    ReRAM's low voltage and low current programmability are attractive features to solve the scaling issues of conventional floating gate Flash. However, read instability in ReRAM is a critical issue, due to random telegraph noise (RTN), sensitivity to disturb and retention. In this work, the array-level characteristics of read stability in 50 nm AlxOy ReRAM are investigated and a circuit technique to improve stability is proposed and evaluated. First, in order to quantitatively assess memory cell stability, a method of stability characterization is defined. Next, based on this methodology, a proposal to improve read stability, called ;stability check loop; is evaluated. The stability check loop is a stability verification procedure, by which, instability improvement of 7×, and read error rate improvement of 40% are obtained.

  18. Research on the Influence Factors of Emulsion Stability of Oil-in-water Drilling Fluid

    Science.gov (United States)

    Li, Xiaoxu; Sun, Yuxue; Chen, Xiangming; Wang, Zengkui; Xu, Jianjun

    2018-01-01

    The evaluation standard of emulsion stability of oil-in-water drilling fluid is determined in this paper, based on which an evaluation analysis is conducted for the influence factors of emulsion stability, including the addition of emulsifier, addition of stabilizer, stirring speed, weighing agent, clay, etc. to gain the corresponding regularity understanding.

  19. Impact of fat and water crystallization on the stability of hydrogenated palm oil-in-water emulsions stabilized by a nonionic surfactant.

    Science.gov (United States)

    Thanasukarn, Parita; Pongsawatmanit, Rungnaphar; McClements, D Julian

    2006-05-17

    The influence of (0-40 wt %) sucrose and (0 and 150 mmol/kg) sodium chloride on the physical properties of 20 wt % hydrogenated palm oil-in-water emulsions stabilized by 2 wt % Tween 20 after crystallization of the oil phase only or both the oil and water phases has been examined. Emulsion stability was assessed by differential scanning calorimetry measurements of fat destabilization after cooling-heating cycles and by measurements of mean particle size, percent destabilized fat, and percent free oil obtained from gravitational separation after isothermal storage (at -40 to +37 degrees C). At storage temperatures where the oil phase was partially crystalline and the water was completely liquid, the emulsions were unstable to droplet coalescence and oiling off because of partial coalescence. Both NaCI and sucrose increased the extent of partial coalescence in the emulsions. At storage temperatures where both oil and water crystallized, the emulsions were completely destabilized. The stability of the emulsions to freezing and thawing could be improved somewhat by adding sucrose (>20 wt %). Emulsions stabilized by whey proteins were shown to have better freeze-thaw stability than those stabilized by Tween 20, especially in the presence of sucrose. These results may help formulate food emulsions with improved freeze-thaw stability.

  20. 46 CFR 178.340 - Stability standards for pontoon vessels on protected waters.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Stability standards for pontoon vessels on protected waters. 178.340 Section 178.340 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL....340 Stability standards for pontoon vessels on protected waters. (a) The portion of the deck...

  1. Structure, spectra and stability of a tetrafluoromethane-water complex.

    Science.gov (United States)

    Mierzwicki, Krzysztof; Mielke, Zofia; Sałdyka, Magdalena; Coussan, Stephane; Roubin, Pascale

    2008-03-07

    The complex formed between water and tetrafluoromethane has been studied by infrared matrix isolation spectroscopy and ab initio calculations. The geometries of the CF4-H2O complexes were optimized in two steps at the MP2/aug-cc-pVTZ level of theory. The structure found at this level was reoptimized on the CP-corrected potential energy surface. The interaction energy was partitioned according to the SAPT scheme and the topological analysis of the electron density was performed. The optimized structure corresponds to the nonhydrogen bonded complex with an oxygen atom of water oriented toward the carbon atom of CF4. The infrared spectra of CF4-H2O /Ne(Ar) matrices demonstrate the presence of a well defined CF4-H2O structure in accord with theoretical prediction. Two complex vibrations were identified in the spectra of neon matrices and four vibrations were observed in the spectra of argon matrices. The available experimental data are in accord with the CP-corrected calculated data.

  2. Stability analysis of supercritical-pressure light water-cooled reactor in constant pressure operation

    International Nuclear Information System (INIS)

    Suhwan, JI; Shirahama, H.; Koshizuka, S.; Oka, Y.

    2001-01-01

    The purpose of this study is to evaluate the thermal-hydraulic and the thermal-nuclear coupled stabilities of a supercritical pressure light water-cooled reactor. A stability analysis code at supercritical pressure is developed. Using this code, stabilities of full and partial-power reactor operating at supercritical pressure are investigated by the frequency-domain analysis. Two types of SCRs are analyzed; a supercritical light water reactor (SCLWR) and a supercritical water-cooled fast reactor (SCFR). The same stability criteria as Boiling Water Reactor are applied. The thermal-hydraulic stability of SCLWR and SCFR satisfies the criteria with a reasonable orifice loss coefficient. The decay ratio of the thermal-nuclear coupled stability in SCFR is almost zero because of a small coolant density coefficient of the fast reactor. The evaluated decay ratio of the thermal-nuclear coupled stability is 3,41 ∼ 10 -V at 100% power in SCFR and 0,028 at 100% power in SCLWR. The sensitivity is investigated. It is found that the thermal-hydraulic stability is sensitive to the mass flow rate strongly and the thermal-nuclear coupled stability to the coolant density coefficient. The bottom power peak distribution makes the thermal-nuclear stability worse and the thermal-nuclear stability better. (author)

  3. Salt marsh stability modelled in relation to sea level rise

    DEFF Research Database (Denmark)

    Bartholdy, Jesper; Bartholdy, Anders; Kroon, Aart

    2010-01-01

    Accretion on a natural backbarrier salt marsh was modeled as a function of high tide level, initial salt marsh level and distance to the source. Calibration of the model was based on up to ca 80 year old marker horizons, supplemented by 210Pb/137Cs datings and subsequent measurements of clay...... that mass depth down core can be directly related to the bulk dry density of the surface layer by means of a logarithmic function. The results allow for an evaluation of the use of marker horizons in the topmost layers and show that it is important to know the level of the marker in relation to the salt...

  4. Analysis of water-level fluctuations in Wisconsin wells

    Science.gov (United States)

    Patterson, G.L.; Zaporozec, A.

    1987-01-01

    More than 60 percent of the residents of Wisconsin use ground water as their primary water source. Water supplies presently are abundant, but ground-water levels continually fluctuate in response to natural factors and human-related stresses. A better understanding of the magnitude, duration, and frequency of past fluctuations, and the factors controlling these fluctuations may help anticipate future changes in ground-water levels.

  5. Development of the Technologies for Stabilization Treatment of the Water of the Recycling Cooling Systems at Thermal Power Plants

    Science.gov (United States)

    Vlasov, S. M.; Chichirova, N. D.; Chichirov, A. A.; Vlasova, A. Yu.; Filimonova, A. A.; Prosvirnina, D. V.

    2018-02-01

    A turbine-condensate cooling system is one of the less stable and most hard-to-control systems of maintaining optimal water chemistry. A laboratory recycling cooling water test facility, UVO-0.3, was developed for physical simulation of innovative zero-discharge water chemistry conditions and improvement of technological flowcharts of stabilization treatment of the initial and circulating water of the recycling cooling systems at thermal power plants. Experiments were conducted in the UVO-0.3 facility to investigate the processes that occur in the recycling water supply system and master new technologies of stabilization of the initial and circulating water. It is shown that, when using untreated initial water, scaling cannot be prevented even under low concentration levels. The main reason for the activation of scale depositing is the desorption of carbon dioxide that results in alkalization of the circulating water and, as a consequence, a displacement of the chemical reaction equilibrium towards the formation of slightly soluble hardness ions. Some techniques, viz., liming and alkalization of the initial water and the by-pass treatment of the circulating water, are considered. New engineering solutions have been developed for reducing the amount of scale-forming substances in the initial and circulating water. The best results were obtained by pretreating the initial water with alkalizing agents and simultaneously bypassing and treating part of the circulating water. The obtained experimental data underlie the process flowcharts of stabilization treatment of the initial and circulating TPP water that ensure scale-free and noncorrosive operation and meet the corresponding environmental requirements. Under the bypassing, the specific rates of the agents and the residual hardness are reduced compared with the conventional pretreatment.

  6. Use of alum water treatment sludge to stabilize C and immobilize P and metals in composts.

    Science.gov (United States)

    Haynes, R J; Zhou, Y-F

    2015-09-01

    Alum water treatment sludge is composed of amorphous hydroxyl-Al, which has variable charge surfaces with a large Brunauer-Emmett-Teller (BET) surface area (103 m(-2) g(-1)) capable of specific adsorption of organic matter molecules, phosphate, and heavy metals. The effects of adding dried, ground, alum water treatment sludge (10% w/w) to the feedstock for composting municipal green waste alone, green waste plus poultry manure, or green waste plus biosolids were determined. Addition of water treatment sludge reduced water soluble C, microbial biomass C, CO2 evolution, extractable P, and extractable heavy metals during composting. The decrease in CO2 evolution (i.e., C sequestration) was greatest for poultry manure and least for biosolid composts. The effects of addition of water treatment sludge to mature green waste-based poultry manure and biosolid composts were also determined in a 24-week incubation experiment. The composts were either incubated alone or after addition to a soil. Extractable P and heavy metal concentrations were decreased by additions of water treatment sludge in all treatments, and CO2 evolution was also reduced from the poultry manure compost over the first 16-18 weeks. However, for biosolid compost, addition of water treatment sludge increased microbial biomass C and CO2 evolution rate over the entire 24-week incubation period. This was attributed to the greatly reduced extractable heavy metal concentrations (As, Cr, Cu, Pb, and Zn) present following addition of water treatment sludge, and thus increased microbial activity. It was concluded that addition of water treatment sludge reduces concentrations of extractable P and heavy metals in composts and that its effect on organic matter stabilization is much greater during the composting process than for mature compost because levels of easily decomposable organic matter are initially much higher in the feedstock than those in matured composts.

  7. Hydraulic modelling for analysis of the hot water layer stability in research reactor

    International Nuclear Information System (INIS)

    Ribeiro, Rogerio; Yanagihara, Jurandir Itizo

    1995-01-01

    Pool reactors are research reactors, which allow easy access to the core and are simple to operate. Reactors of this kind operating at power levels higher than about one megawatt need a hot water layer at the surface of the pool, in order to keep surface activity below acceptable levels and enable free access to the upper part of the reactor. This work presents similitude criteria derived by dimensional analysis and by non dimensioning the basic equations to analyze this layer's stability in a reduced scale model. The flow in the reactor is complex. It is impossible to consider all the phenomena with a single similitude criterion. The best would be to construct several models considering all the similitude criteria and then combine the results. Economical reasons and available time in the majority of the cases are a restrain to this procedure. Then, the most important criteria to the considered phenomenon must be chosen in order to give the best results. This work identifies three similitude criteria that were considered important to analyze the pool reactor's hot water layer stability. (author)

  8. Boiling water reactor stability revisited: The effects of flashing

    Energy Technology Data Exchange (ETDEWEB)

    Yadigaroglu, G. [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH, ETH-Zentrum, CLT-C1, CH-8092 Zurich (Switzerland)]. E-mail: yadi@ethz.ch; Askari, B. [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH, ETH-Zentrum, CLT-C1, CH-8092 Zurich (Switzerland)

    2005-05-01

    There are numerous investigations of two-phase flow stability with particular emphasis to BWR stability; these have become increasingly sophisticated and complete over the years. The basic features of a new development and frequency-domain code capable of considering all the channels (bundles) in a BWR, flashing of the coolant at low pressure, full coupling with 3D, two-group neutronics, etc. are described. The basic thermal-hydraulic model is used to study the effects of flashing on stability in a BWR-like channel. The behavior of the channel is highly dynamic. Contrary to what could have been intuitively guessed, the effect of flashing is stabilizing; the reasons and mechanisms leading to this are discussed.

  9. Boiling water reactor stability revisited: The effects of flashing

    International Nuclear Information System (INIS)

    Yadigaroglu, G.; Askari, B.

    2005-01-01

    There are numerous investigations of two-phase flow stability with particular emphasis to BWR stability; these have become increasingly sophisticated and complete over the years. The basic features of a new development and frequency-domain code capable of considering all the channels (bundles) in a BWR, flashing of the coolant at low pressure, full coupling with 3D, two-group neutronics, etc. are described. The basic thermal-hydraulic model is used to study the effects of flashing on stability in a BWR-like channel. The behavior of the channel is highly dynamic. Contrary to what could have been intuitively guessed, the effect of flashing is stabilizing; the reasons and mechanisms leading to this are discussed

  10. Advanced nonlinear stability analysis of boiling water nuclear reactors

    OpenAIRE

    Lange, Carsten

    2009-01-01

    This thesis is concerned with nonlinear analyses of BWR stability behaviour, contributing to a deeper understanding in this field. Despite negative feedback-coefficients of a BWR, there are operational points (OP) at which oscillatory instabilities occur. So far, a comprehensive and an in-depth understanding of the nonlinear BWR stability behaviour are missing, even though the impact of the significant physical parameters is well known. In particular, this concerns parameter regions in whi...

  11. Water levels in the Yucca Mountain area, Nevada, 1993

    International Nuclear Information System (INIS)

    Tucci, P.; Goemaat, R.L.; Burkhardt, D.J.

    1996-01-01

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

  12. Stability monitoring of a natural-circulation-cooled boiling water reactor

    International Nuclear Information System (INIS)

    Hagen, T.H.J.J. van der.

    1989-01-01

    Methods for monitoring the stability of a boiling water reactor (BWR) are discussed. Surveillance of BWR stability is of importance as problems were encountered in several large reactors. Moreover, surveying stability allows plant owners to operate at high power with acceptable stability margins. The results of experiments performed on the Dodewaard BWR (the Netherlands) are reported. This type reactor is cooled by natural circulation, a cooling principle that is also being considered for new reactor designs. The stability of this reactor was studied both with deterministic methods and by noise analysis. Three types of stability are distinguished and were investigated separately: reactor-kinetic stability, thermal-hydraulic stability and total-plant stability. It is shown that the Dodewaard reactor has very large stability margins. A simple yet reliable stability criterion is introduced. It can be derived on-line from thhe noise signal of ex-vessel neutron detectors during normal operation. The sensitivity of neutron detectors to in-core flux perturbations - reflected in the field-of-view of the detector - was calculated in order to insure proper stability surveillance. A novel technique is presented which enables the determination of variations of the in-core coolant velocity by noise correlation. The velocity measured was interpreted on the basis of experiments performed on the air/water flow in a model of a BWR coolant channel. It appeared from this analysis that the velocity measured was much higher than the volume-averaged water and air velocities and the volumetric flux. The applicability of the above-mentioned technique to monitoring of local channel-flow stability was tested. It was observed that stability effects on the coolant velocity are masked by other effects originating from the local flow pattern. Experimental and theoretical studies show a shorter effective fuel time constant in a BWR than was assumed. (author). 118 refs.; 73 figs.; 21 tabs

  13. STABILITY: AN INVESTIGATION OF AS(III)/AS(V) STABILITY IN IRON RICH DRINKING WATER MATRICES

    Science.gov (United States)

    Arsenic in drinking water is predominantly inorganic arsenic. The two oxidation states of inorganic arsenic are As(III)(pKa=9.3) and As(V)(pKa2=6.9). The distribution of As(III) and AS(V) in a water is dependent on the redox potential of the water. The actual distribution can ...

  14. Water levels in observation wells in Nebraska during 1955

    Science.gov (United States)

    Keech, C.F.

    1956-01-01

    The objective of the dbservation-well program in Nebraska is to provide an evaluation of the status of the ground-water supplies. Many uses for water-.level data are known but not all potential uses can be forseen. Among the important uses are the following:To indicate the status of ground water in storage or in transit and the availability of supplies.To show the trend of ground-water supplies and the outlook for the future.To estimate or forcast the base flow of streams.To indicate areas in which the water level is approaching too close to the land surface (water-logging) or is receding toward economic limits of lift or tow rd impairment by water of poor quality.To provide long-term vidence for evaluating the effectiveness of land-management and water...0 nservation programs in relation to water conservation actually of ected, and for use in basin or "watershed" studies.To provide longterm ontinuous records to serve as a framework to which short-term records collected during intensive investigation may be related.The water level in an observation well functions as a gage to indicate the position of the water table o The water table is defined as the upper surface of the zone of saturation except where that surface is formed by overlying impermeable materials. The water table is also the boundary between the zone of saturation and the zone of aeration. It is not a level surface but is a sloping surface that has many irregularities, and it often conforms in a general way to the land surface. The irregularities are caused by several factors. In places where the recharge to the ground-water reservoir is exceptionally large, the water-table may rise to form a mound from which the water slowly spreads. Depressions or troughs in the water table indicate places where the ground water is discharging, as along streams that are below the normal level of the water table, or indicate places where water is being withdrawn by wells or vegetation.The several factors that

  15. Lake water levels across the U.S.: What are the spatial patterns and drivers of water level change?

    Science.gov (United States)

    Background Lake water-level changes affect the physical, chemical, and biological condition of lakes; and we expect that disturbances such as land use conversion, water withdrawal, and climate change may alter water-level regimes and impact lake integrity. However, we have a poor...

  16. The study of stability, combustion characteristics and performance of water in diesel emulsion fuel

    Directory of Open Access Journals (Sweden)

    Syafiq Zulkifli

    2017-01-01

    Full Text Available A single cylinder diesel engine study of water in diesel emulsions was conducted to investigate the stability effect of emulsion fuel on three different fuel blends and the water emulsification effect on the engine performance. Emulsified fuels contained 2% of surfactant including Span 80 Tween 80 and tested 10 HLB number. The blends also varied of 5%, 10% and 15% of water in diesel ratios namely as BSW5, BSW10 and BSW15. The fuel blends performance was tested using a single cylinder, direct injection diesel engine, operating at 1860 rpm. The results on stability reveal that high shear homogenizer yields more stability on emulsion fuel than mechanical stirrer and ultrasonic water bath. The engine performance results show that the ignition delay and peak pressure increase with the increment of water percentage up to 15%. However, the results indicate the increment of water percentage is also shows a significant decrease in engine power.

  17. Boiling water reactors stability analysis - a challenge for the study of complex nonlinear dynamical systems

    International Nuclear Information System (INIS)

    Hennig, D.

    1997-01-01

    In boiling water reactors, there is a region in the operating map for which the reactor exhibits stable or unstable power oscillations. This oscillatory behaviour had to be understood in detail, in order to estimate, in a reliable way, the stability limits. This paper describes the BWR stability analysis methodology used at PSI and presents some recent results. (author) figs., tab., 38 refs

  18. In-flight oxidation of iron particles sprayed using gas and water stabilized plasma torch

    Czech Academy of Sciences Publication Activity Database

    Espie, G.; Denoirjean, A.; Fauchais, P.; Clabbe, J.C.; Dubský, Jiří; Schneeweiss, O.; Voleník, Karel

    2005-01-01

    Roč. 195, č. 1 (2005), s. 17-28 ISSN 0257-8972 Institutional research plan: CEZ:AV0Z20430508 Keywords : in-flight oxidation * gas stabilized plasma * water stabilized plasma Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.646, year: 2005

  19. ZVI (Fe0 Desalination: Stability of Product Water

    Directory of Open Access Journals (Sweden)

    David D. J. Antia

    2016-03-01

    Full Text Available A batch-operated ZVI (zero valent iron desalination reactor will be able to partially desalinate water. This water can be stored in an impoundment, reservoir or tank, prior to use for irrigation. Commercial development of this technology requires assurance that the partially-desalinated product water will not resalinate, while it is in storage. This study has used direct ion analyses to confirm that the product water from a gas-pressured ZVI desalination reactor maintains a stable salinity in storage over a period of 1–2.5 years. Two-point-three-litre samples of the feed water (2–10.68 g (Na+ + Cl−·L−1 and product water (0.1–5.02 g (Na+ + Cl−·L−1 from 21 trials were placed in storage at ambient (non-isothermal temperatures (which fluctuated between −10 and 25 °C, for a period of 1–2.5 years. The ion concentrations (Na+ and Cl− of the stored feed water and product water were then reanalysed. The ion analyses of the stored water samples demonstrated: (i that the product water salinity (Na+ and Cl− remains unchanged in storage; and (ii the Na:Cl molar ratios can be lower in the product water than the feed water. The significance of the results is discussed in terms of the various potential desalination routes. These trial data are supplemented with the results from 122 trials to demonstrate that: (i reactivity does not decline with successive batches; (ii the process is catalytic; and (iii the process involves a number of steps.

  20. Underwater noise levels in UK waters

    OpenAIRE

    Merchant, Nathan D.; Brookes, Kate L.; Faulkner, Rebecca C.; Bicknell, Anthony W. J.; Godley, Brendan J.; Witt, Matthew J.

    2016-01-01

    Underwater noise from human activities appears to be rising, with ramifications for acoustically sensitive marine organisms and the functioning of marine ecosystems. Policymakers are beginning to address the risk of ecological impact, but are constrained by a lack of data on current and historic noise levels. Here, we present the first nationally coordinated effort to quantify underwater noise levels, in support of UK policy objectives under the EU Marine Strategy Framework Directive (MSFD). ...

  1. Water levels in the Yucca Mountain area, Nevada, 1995

    International Nuclear Information System (INIS)

    Graves, R.P.; Goemaat, R.L.

    1998-01-01

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

  2. Climate-driven changes in water level

    DEFF Research Database (Denmark)

    Hansen, Rikke Bjerring; Olsen, Jesper; Jeppesen, Erik

    2013-01-01

    throughout the period. The lake did not return to its pre-8.2-ka event status during the period of analysis, but remained more productive for centuries after the climatic anomaly as judged from the pigment accumulation and assemblage composition. The change to more eutrophic conditions may have been...... rates of cladoceran subfossils and algal pigments, possibly due to increased turbidity and reduced nutrient input during this drier period. Pigment analysis also showed added importance of diatoms and cryptophytes during this climate anomaly, while cyanobacteria became more important when the water...

  3. Stabilization of liquid low-level and mixed wastes: a treatability study

    International Nuclear Information System (INIS)

    Carson, S.; Cheng, Yu-Cheng; Yellowhorse, L.; Peterson, P.

    1996-01-01

    A treatability study has been conducted on liquid low-level and mixed wastes using the stabilization agents Aquaset, Aquaset II, Aquaset II-H, Petroset, Petroset-H, and Petroset and Petroset II. A total of 40 different waste types with activities ranging from 10 -14 to 10 -4 curies/ml have been stabilized. Reported data for each waste include its chemical and radiological composition and the optimum composition or range of compositions (weight of agent/volume of waste) for each stabilization agent used. All wastes were successfully stabilized with one or more of the stabilization agents and all final waste forms passed the Paint Filter Liquids Test (EPA Method 9095)

  4. Stabilization of liquid low-level and mixed wastes: a treatability study

    Energy Technology Data Exchange (ETDEWEB)

    Carson, S.; Cheng, Yu-Cheng; Yellowhorse, L.; Peterson, P.

    1996-02-01

    A treatability study has been conducted on liquid low-level and mixed wastes using the stabilization agents Aquaset, Aquaset II, Aquaset II-H, Petroset, Petroset-H, and Petroset and Petroset II. A total of 40 different waste types with activities ranging from 10{sup {minus}14} to 10{sup {minus}4} curies/ml have been stabilized. Reported data for each waste include its chemical and radiological composition and the optimum composition or range of compositions (weight of agent/volume of waste) for each stabilization agent used. All wastes were successfully stabilized with one or more of the stabilization agents and all final waste forms passed the Paint Filter Liquids Test (EPA Method 9095).

  5. Underwater noise levels in UK waters.

    Science.gov (United States)

    Merchant, Nathan D; Brookes, Kate L; Faulkner, Rebecca C; Bicknell, Anthony W J; Godley, Brendan J; Witt, Matthew J

    2016-11-10

    Underwater noise from human activities appears to be rising, with ramifications for acoustically sensitive marine organisms and the functioning of marine ecosystems. Policymakers are beginning to address the risk of ecological impact, but are constrained by a lack of data on current and historic noise levels. Here, we present the first nationally coordinated effort to quantify underwater noise levels, in support of UK policy objectives under the EU Marine Strategy Framework Directive (MSFD). Field measurements were made during 2013-2014 at twelve sites around the UK. Median noise levels ranged from 81.5-95.5 dB re 1 μPa for one-third octave bands from 63-500 Hz. Noise exposure varied considerably, with little anthropogenic influence at the Celtic Sea site, to several North Sea sites with persistent vessel noise. Comparison of acoustic metrics found that the RMS level (conventionally used to represent the mean) was highly skewed by outliers, exceeding the 97 th percentile at some frequencies. We conclude that environmental indicators of anthropogenic noise should instead use percentiles, to ensure statistical robustness. Power analysis indicated that at least three decades of continuous monitoring would be required to detect trends of similar magnitude to historic rises in noise levels observed in the Northeast Pacific.

  6. Effects of reservoirs water level variations on fish recruitment

    Directory of Open Access Journals (Sweden)

    Fabíula T. de Lima

    2017-10-01

    Full Text Available ABSTRACT The construction of hydroelectric power plants has many social and environmental impacts. Among them, the impacts on fish communities, which habitats are drastically modified by dams, with consequences across the ecosystem. This study aimed to assess the influence of water level (WL variations in the reservoirs of the Itá and Machadinho hydroelectric plants on the recruitment of fish species from the upper Uruguay River in southern Brazil. The data analyzed resulted from the WL variation produced exclusively by the hydroelectric plants generation and were collected between the years 2001 and 2012. The results showed significant correlations between the abundance of juvenile fish and the hydrological parameters only for some reproductive guilds. The species that spawn in nests showed, in general, a clear preference for the stability in the WL of the reservoirs, while the species that spawn in macrophytes or that release demersal eggs showed no significant correlation between the abundance of juvenile fish and hydrological parameters. A divergence of results between the two reservoirs was observed between the species that release semi-dense eggs; a positive correlation with a more stable WL was only observed in the Machadinho reservoir. This result can be driven by a wider range of WL variation in Machadinho reservoir.

  7. Collector feedwater supply and stability of the power distribution in a pressurized-water reactor

    International Nuclear Information System (INIS)

    Budnikov, V.I.; Kosolapov, S.V.; Kramerov, A.Ya.

    1980-01-01

    It is necessary to determine how the collector feedwater supply affects the disposition of the stability limits and the instability period for the power distribution in such a reactor. The main reason for the fluctuations in feedwater flow rate were shown by additional calculations with the general power regulator switched out to be due to instability on the fundamental in the neutron distribution. The power-level fluctuations are due to oscillation of the feed valve in the level regulator, and consequently to oscillations in the feedwater flow rate. If collector feed is to be employed, it is desirable to improve the response of the pressure control system for the separator drum, because under certain emergency conditions there will be a considerable fall in pressure in the separator drum. The deviation from saturation for the water in the separator drum tube is less in the second method than it is in the first, so the cavitation margin in the principal pumps may be reduced somewhat. Calculations show that this reduction will not occur if the time constant of the turbine synchronizer is about 10 sec. Also, the dynamic characteristics of the nuclear power station in these modes of feedwater supply are appreciably influenced by the parameters of the pressure-control system and the water-level control for the separator drum

  8. Critical water stress levels in Pinus patula seedlings and their ...

    African Journals Online (AJOL)

    Critical water stress levels in Pinus patula seedlings and their relation to measures of seedling morphology. ... Southern Forests: a Journal of Forest Science ... A pot trial was implemented to determine the effect of soil water stress following transplanting on shoot water potential and stomatal conductance of Pinus patula ...

  9. Determination of the Level of Contamination of Underground Water ...

    African Journals Online (AJOL)

    The aim of this study is to determine the level of contamination of hand-dug well which is one of the major source of water supply for the population. Water samples were taken from a total of fifteen wells at the vicinity of three major refuse dumpsite taking measurement of depth of the well, diameter, volume of water, distance ...

  10. Contact angles of wetting and water stability of soil structure

    Science.gov (United States)

    Kholodov, V. A.; Yaroslavtseva, N. V.; Yashin, M. A.; Frid, A. S.; Lazarev, V. I.; Tyugai, Z. N.; Milanovskiy, E. Yu.

    2015-06-01

    From the soddy-podzolic soils and typical chernozems of different texture and land use, dry 3-1 mm aggregates were isolated and sieved in water. As a result, water-stable aggregates and water-unstable particles composing dry 3-1 mm aggregates were obtained. These preparations were ground, and contact angles of wetting were determined by the static sessile drop method. The angles varied from 11° to 85°. In most cases, the values of the angles for the water-stable aggregates significantly exceeded those for the water-unstable components. In terms of carbon content in structural units, there was no correlation between these parameters. When analyzing the soil varieties separately, the significant positive correlation between the carbon content and contact angle of aggregates was revealed only for the loamy-clayey typical chernozem. Based on the multivariate analysis of variance, the value of contact wetting angle was shown to be determined by the structural units belonging to water-stable or water-unstable components of macroaggregates and by the land use type. In addition, along with these parameters, the texture has an indirect effect.

  11. Stabilization of Aley river water content by forest stands

    Directory of Open Access Journals (Sweden)

    E. G. Paramonov

    2016-06-01

    Full Text Available Aley river basin is one of the most developed territories in West Siberia. Initially, the development here was related to the development of ore mining in the Altai. Currently it is associated mainly with the agricultural orientation of economic development. The intensive involvement of basin lands into the economic turnover for the last 100 years contributed to the formation of a number of environmental problems, such as water and wind erosion, loss of soil fertility and salinization, and desertification of the territory. Besides, the decrease of Aley river water content due to natural and anthropogenic reasons was observed. A specific feature of water management in Aley river basin is a significant amount of water resources used for irrigation purposes and agricultural water supply. To ensure the economic and drinking water supply, two reservoirs and a number of ponds have been constructed and operate in the basin. Forest ecosystems of the basin are considered from the viewpoint of preservation and restoration of small rivers. The ability of forest to accumulate solid precipitation and intercept them during the snowmelt for a longer time reduces the surface drainage and promotes transfer into the subsurface flow, significantly influencing the water content of permanent watercourses, is shown. The state of protective forest plantations in Aley river basin is analyzed. Aley river tributaries are compared by area, the length of water flow, and forest coverage of the basin. It is proposed to regulate the runoff through drastic actions on the increase of forest cover in the plain and especially in the mountainous parts of the basin. Measures to increase the forest cover within water protection zones, afforestation of temporary and permanent river basins, and the protection of agricultural soil fertility are worked out.

  12. Effect of water cadmium concentration and water level on the growth performance of Salix triandroides cuttings.

    Science.gov (United States)

    Yao, Xin; Ma, Fengfeng; Li, Youzhi; Ding, Xiaohui; Zou, Dongsheng; Niu, Yandong; Bian, Hualin; Deng, Jiajun

    2018-03-01

    The growth performance of Salix triandroides cuttings at three water cadmium (Cd) concentrations (0, 20, and 40 mg L -1 ) and three water levels (- 40 cm, water level 40 cm below the soil surface; 0 cm, water level even with the soil surface; and 40 cm, water level 40 cm above soil surface) was investigated to evaluate its potential in phytoextraction strategies. Compared to cuttings in the - 40 or 0 cm water levels, cuttings in the 40 cm water level showed significantly lower biomass, height, and adventitious root length and significantly fewer leaves and adventitious roots. However, these growth and morphological parameters were not different among the three water Cd concentrations. Water level decreased stomatal conduction and transpiration rate but showed no significant effects on chlorophyll concentration or photosynthetic rate. Chlorophyll concentration and stomatal conductance were higher at 40 mg L -1 Cd treatment than at 0 or 20 mg L -1 Cd treatment; yet, photosynthetic rate and transpiration rate were not different. Cd concentration in the leaves and stems increased as the water level increased, but the highest Cd concentration in the roots occurred in the 0 cm water level. As water Cd concentration increased, Cd concentration in the leaves, stems, and roots increased in all three water levels, except in stems in the - 40 cm water level. Under Cd stress, cuttings in the - 40 or 0 cm water levels were characterized by a higher bioaccumulation coefficient, but a lower translocation factor, than those in the 40 cm water level. However, the bioaccumulation coefficient increased with increasing water Cd concentration in all three water levels, as did the translocation factor in the 40 cm water level. The tolerance index for the cuttings was the same among all water levels and water Cd concentrations. The results clearly indicated that the low water level increased plant growth and Cd accumulation in underground parts, while the high

  13. A siphon gage for monitoring surface-water levels

    Science.gov (United States)

    McCobb, T.D.; LeBlanc, D.R.; Socolow, R.S.

    1999-01-01

    A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold regions cause discontinuity and inaccuracy in the data collected. Installation and field testing of a siphon gage using 0.75-in-diameter polyethylene tubing at Ashumet Pond in Falmouth, Massachusetts, demonstrated that the siphon gage can provide long-term data with a field effort and accuracy equivalent to measurement of ground-water levels at an observation well.A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold

  14. Preparation and Application of Water-in-Oil Emulsions Stabilized by Modified Graphene Oxide

    Directory of Open Access Journals (Sweden)

    Xiaoma Fei

    2016-08-01

    Full Text Available A series of alkyl chain modified graphene oxides (AmGO with different alkyl chain length and content was fabricated using a reducing reaction between graphene oxide (GO and alkyl amine. Then AmGO was used as a graphene-based particle emulsifier to stabilize Pickering emulsion. Compared with the emulsion stabilized by GO, which was oil-in-water type, all the emulsions stabilized by AmGO were water-in-oil type. The effects of alkyl chain length and alkyl chain content on the emulsion properties of AmGO were investigated. The emulsions stabilized by AmGO showed good stability within a wide range of pH (from pH = 1 to pH = 13 and salt concentrations (from 0.1 to 1000 mM. In addition, the application of water-in-oil emulsions stabilized by AmGO was investigated. AmGO/polyaniline nanocomposite (AmGO/PANi was prepared through an emulsion approach, and its supercapacitor performance was investigated. This research broadens the application of AmGO as a water-in-oil type emulsion stabilizer and in preparing graphene-based functional materials.

  15. Muscular condition and trunk stability in judoka of national and international level

    Directory of Open Access Journals (Sweden)

    Casto Juan-Recio

    2013-12-01

    Full Text Available Background: It is theorized that the development of the ability to stabilize the trunk may improve the performance of a judoka because it improves body balance control and optimizes force transmission from the lower extremities to the upper limbs. However, there is a lack of scientific evidence to establish a clear relationship between trunk stability and performance in judo.Aim: The purpose of this study was to determine whether the quantification of trunk stability and muscular strength and endurance allowed differentiation between national level (n = 7 and international level judoka (n = 6. In addition, the relationship between trunk stability and muscular strength and endurance of the muscles involved in trunk stability control was analyzed.Method: To assess trunk stability, trunk responses to sudden loads applied by a pneumatic mechanism were analyzed, as well as trunk postural control through an unstable sitting paradigm. Muscular strength and endurance were assessed via a flexion and extension trunk test using an isokinetic dynamometer.Results/Conclusions: International level judokas showed lower CoP displacement in the most complex task in unstable seat (7.00 ± 1.19 vs 8.93 ± 1.45 mm, T = .025 and higher absolute and relative peak torque in extensor muscles (7.05 ± 0.87 vs 5.74 ± 0.72 Nm, T = .013 than national level judoka. According to these results, core stability and trunk muscular condition are important qualities in the physical training of elite judoka. Correlational analysis found no relation between the analyzed variables, thus muscular strength and endurance appear to have a non-significant effect on performance in the trunk stability tests.

  16. Do wave heights and water levels increase ocean lifeguard rescues?

    Science.gov (United States)

    Koon, William; Rowhani-Rahbar, Ali; Quan, Linda

    2017-12-05

    To investigate the association of wave height and tidal water level changes with the frequency of ocean lifeguard rescues. All ocean lifeguard rescues recorded by Newport Beach Lifeguards in 2015 and 2016 were linked by time and location to weather and ocean variables contained in other historical databases. We performed separate multivariable analyses using mixed effects negative binomial regression to evaluate the total effects of wave height, mean water level (primarily set by tidal elevation), and rising vs. falling water level, on the frequency of ocean rescue in the study location, controlling for confounding variables. Newport Beach Lifeguards made 8046 rescues during the study period. In all areas of the beach, rescue frequency increased as waves got larger (IRR: 3.25; 95%CI: 2.91-3.79) but then decreased in large surf (IRR: 0.52; 95%CI: 0.37-0.73). In two sections of beach, lifeguards made more rescues during lower water levels, but in the third section of beach, made more rescues during higher water levels. Rescue frequency increased in two sections of beach with rising water levels, but did not in the other section. Wave height, water level, and water level direction were associated with rescue frequency, but the environmental factors included in the analysis did not fully account for most variation in rescue frequency. Other factors need to be evaluated to identify major determinants of rescue frequency. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Contamination levels of domestic water sources in Maiduguri ...

    African Journals Online (AJOL)

    The study examines the levels of contamination of domestic water sources in Maiduguri Metropolis area of Borno State based on their physicochemical and bacteriological properties. It was informed by the global concern on good drinking water quality which is an indicator of development level; hence the focus on domestic ...

  18. Supercritical water natural circulation flow stability experiment research

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Dongliang; Zhou, Tao; Li, Bing [North China Electric Power Univ., Beijing (China). School of Nuclear Science and Engineering; North China Electric Power Univ., Beijing (China). Inst. of Nuclear Thermalhydraulic Safety and Standardization; North China Electric Power Univ., Beijing (China). Beijing Key Lab. of Passive Safety Technology for Nuclear Energy; Huang, Yanping [Nuclear Power Institute of China, Chengdu (China). Science and Technology on Reactor System Design Technology Lab.

    2017-12-15

    The Thermal hydraulic characteristics of supercritical water natural circulation plays an important role in the safety of the Generation-IV supercritical water-cooled reactors. Hence it is crucial to conduct the natural circulation heat transfer experiment of supercritical water. The heat transfer characteristics have been studied under different system pressures in the natural circulation systems. Results show that the fluctuations in the subcritical flow rate (for natural circulation) is relatively small, as compared to the supercritical flow rate. By increasing the heating power, it is observed that the amplitude (and time period) of the fluctuation tends to become larger for the natural circulation of supercritical water. This tends to show the presence of flow instability in the supercritical water. It is possible to observe the flow instability phenomenon when the system pressure is suddenly reduced from the supercritical pressure state to the subcritical state. At the test outlet section, the temperature is prone to increase suddenly, whereas the blocking effect may be observed in the inlet section of the experiment.

  19. Concurrent temporal stability of the apparent electrical conductivity and soil water content

    Science.gov (United States)

    Knowledge of spatio-temporal soil water content (SWC) variability within agricultural fields is useful to improve crop management. Spatial patterns of soil water contents can be characterized using the temporal stability analysis, however high density sampling is required. Soil apparent electrical c...

  20. Ionization of water clusters by fast Highly Charged Ions: Stability, fragmentation, energetics and charge mobility

    International Nuclear Information System (INIS)

    Legendre, S; Maisonny, R; Capron, M; Bernigaud, V; Cassimi, A; Gervais, B; Grandin, J-P; Huber, B A; Manil, B; Rousseau, P; Tarisien, M; Adoui, L; Lopez-Tarifa, P; AlcamI, M; MartIn, F; Politis, M-F; Penhoat, M A Herve du; Vuilleumier, R; Gaigeot, M-P; Tavernelli, I

    2009-01-01

    We study dissociative ionization of water clusters by impact of fast Ni ions. Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) is used to obtain information about stability, energetics and charge mobility of the ionized clusters. An unusual stability of the (H 2 O) 4 H ''+ ion is observed, which could be the signature of the so called ''Eigen'' structure in gas phase water clusters. High charge mobility, responsible for the formation of protonated water clusters that dominate the mass spectrum, is evidenced. These results are supported by CPMD and TDDFT simulations, which also reveal the mechanisms of such mobility.

  1. Structure and stability of spiro-cyclic water clusters

    Indian Academy of Sciences (India)

    Administrator

    donates two protons, resulting in an overall stabili- zation of the spiro-cyclic structure. A close scrutiny. Figure 1. Optimized geometries of different spiro- cyclic water clusters obtained using HF/6-311++G** cal- culation. These clusters are found to be stable without any reorganization during energy minimization at DFT.

  2. [Stability in drinking and surface water of nine virus species from different genera (author's transl)].

    Science.gov (United States)

    Mahnel, H; Ottis, K; Herlyn, M

    1977-01-01

    The stability of nine viruses, Aujeszky, Sindbis, Vesicular Stomatitis, Newcastle Disease, Vaccinia, FMD, HCC, Reo and Teschen virus in drinking and surface water was investigated comparatively at temperatures of 9 and 15 degrees C as well as the influence of water factors like seasonal difference in temperature, pH value, hardness and sort of water. The results can be summarized as follows: 1. At temperatures of 9 to 15 degrees C the majority of the viruses remained stabil in natural water for an astonishing long time. 2. Starting with virus concentration of about 10(4) infectious units per ml Teschen, Vaccinia, Reo, HCC and ND virus could mostly be demonstrated in water longer than 200 days and FMD, Aujeszky, Vesicular Stomatitis and Sindbis virus for 20 to 50 days on average at 9 degrees C. The stability of the viruses investigated decreased in water in the named turn. 3. Based on these results it can be assumed that under natural conditions with very low virus content of some particles the labile viruses such as Toga, Herpes, Rhabdo and pH labile Picorna remain infectious in water for some days. They should not have any importance as water contaminants. More resistant viruses like Paramyxo may keep infectious for weeks and very stabile viruses such as Entero, Reo, Adeno and Pox viruses several weeks to months. 4. As to factors temperature, pH, hardness and sort of water-within the naturally differing range-only the temperature and only in the case of less resistant viruses showed significant influence on the virus stability in water.

  3. Characteristics of soil stability and carbon sequestration under water storage and drainage model

    Science.gov (United States)

    Li, J.; Han, J. C.; Chen, C.; Yang, J. J.

    2017-07-01

    This research was conducted to investigate the influence of saline alkali soil on soil physical properties, stability and organic carbon storage under water storage and drainage, and to provide scientific basis for improving soil quality in Fuping County of Shaanxi Province, China. Saline alkali soil model test was conducted and the process was assessed with two different methods: i) traditional drainage and ecological water storage, measure and analyze 0-30 cm soil bulk density, porosity, field water capacity, mean mass diameter (MWD), geological mean diameter (GMD), stability of water stable aggregate (WASR), aggregate destruction rate (PAD), fractal dimension (D) and; ii) organic carbon storage, comprehensively analyze the relationship between stability index and soil organic carbon. The results show that: (1) compared with traditional drainage treatment, water treatment may effectively reduce the soil bulk density by 1.3%-4.2%, and improve soil porosity and field capacity at the same time; (2) under dry and wet screen treatment, soil stability, the water storing treatment is higher than the drainage treatment. Performance trend of soil MWD and GMD increases with the increase of soil depth. The stability of soil water stable aggregates increased 14.5%-53.4%. The average aggregate destruction rate was 3.2% lower than that of the drainage treatment and the difference is obvious (Pfractal dimension and soil organic carbon storage. The correlation coefficient is, respectively, R2=0.86 and R2=0.94, and the difference is obvious (P<0.05). To sum up, the water storage treatment can effectively improve the soil quality, improve soil stability and soil organic carbon storage, which can be a good control of saline alkali soil.

  4. Status of a study of stabilization and fine positioning of CLIC quadrupoles to the nanometre level

    CERN Document Server

    Artoos, K; Esposito, M; Fernandez Carmona, P; Guinchard, M; Hauviller, C; Janssens, S; Kuzmin, A; Leuxe, R; Moron Ballester, R

    2011-01-01

    Mechanical stability to the nanometre and below is required for the Compact Linear Collider (CLIC) quadrupoles to frequencies as low as 1 Hz. An active stabilization and positioning system based on very stiff piezo electric actuators and inertial reference masses is under study for the Main Beam Quadrupoles (MBQ). The stiff support was selected for robustness against direct forces and for the option of incrementally repositioning the magnet with nanometre resolution. The technical feasibility was demonstrated by a representative test mass being stabilized and repositioned to the required level in the vertical and lateral direction. Technical issues were identified and the development programme of the support, sensors, and controller was continued to increase the performance, integrate the system in the overall controller, adapt to the accelerator environment, and reduce costs. The improvements are implemented in models, test benches, and design of the first stabilized prototype CLIC magnet. The characterizati...

  5. Antifoaming materials in G.S. (Girlder sulfide) heavy water plants. Thermical stability. Pt. 2

    International Nuclear Information System (INIS)

    Delfino, C.A.

    1986-01-01

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2 MPa, up to 230 deg C). About twenty commercial surfactants were studied from the point of view of their thermical stability. (Author) [es

  6. Nano-silver in drinking water and drinking water sources: stability and influences on disinfection by-product formation.

    Science.gov (United States)

    Tugulea, A-M; Bérubé, D; Giddings, M; Lemieux, F; Hnatiw, J; Priem, J; Avramescu, M-L

    2014-10-01

    Nano-silver is increasingly used in consumer products from washing machines and refrigerators to devices marketed for the disinfection of drinking water or recreational water. The nano-silver in these products may be released, ending up in surface water bodies which may be used as drinking water sources. Little information is available about the stability of the nano-silver in sources of drinking water, its fate during drinking water disinfection processes, and its interaction with disinfection agents and disinfection by-products (DBPs). This study aims to investigate the stability of nano-silver in drinking water sources and in the finished drinking water when chlorine and chloramines are used for disinfection and to observe changes in the composition of DBPs formed when nano-silver is present in the source water. A dispersion of nano-silver particles (10 nm; PVP-coated) was used to spike untreated Ottawa River water, treated Ottawa River water, organic-free water, and a groundwater at concentrations of 5 mg/L. The diluted dispersions were kept under stirred and non-stirred conditions for up to 9 months and analyzed weekly using UV absorption to assess the stability of the nano-silver particles. In a separate experiment, Ottawa River water containing nano-silver particles (at 0.1 and 1 mg/L concentration, respectively) was disinfected by adding sodium hypochlorite (a chlorinating agent) in sufficient amounts to maintain a free chlorine residual of approximately 0.4 mg/L after 24 h. The disinfected drinking water was then quenched with ascorbic acid and analyzed for 34 neutral DBPs (trihalomethanes, haloacetonitriles, haloacetaldehydes, 1,1 dichloro-2-propanone, 1,1,1 trichloro-2-propanone, chloropicrin, and cyanogen chloride). The results were compared to the profile of DBPs obtained under the same conditions in the absence of nano-silver and in the presence of an equivalent concentration of Ag(+) ions (as AgNO3). The stability of the nano-silver dispersions in

  7. The Role of Water in the Stability of Cratonic Keels

    Science.gov (United States)

    Peslier, Anne H.; Woodland, Alan B.; Bell, David R.; Lazarov, Marina

    2011-01-01

    Cratons are typically underlain by large, deep, and old lithospheric keels (to greater than 200 km depth, greater than 2.5 Ga old) projecting into the asthenosphere (e.g., Jordan, 1978; Richardson et al., 1984). This has mystified Earth scientists as the dynamic and relatively hot asthenosphere should have eroded away these keels over time (e.g., Sleep, 2003; O'Neill et al., 2008; Karato, 2010). Three key factors have been invoked to explain cratonic root survival: 1) Low density makes the cratonic mantle buoyant (e.g., Poudjom Djomani et al., 2001). 2) Low temperatures (e.g., Pollack, 1986; Boyd, 1987), and 3) low water contents (e.g., Pollack, 1986), would make cratonic roots mechanically strong. Here we address the mechanism of the longevity of continental mantle lithosphere by focusing on the water parameter. Although nominally anhydrous , olivine, pyroxene and garnet can accommodate trace amounts of water in the form of H bonded to structural O in mineral defects (e.g., Bell and Rossman, 1992). Olivine softens by orders of magnitude if water (1-1000 ppm H2O) is added to its structure (e.g., Mackwell et al., 1985). Our recent work has placed constraints on the distribution of water measured in peridotite minerals in the cratonic root beneath the Kaapvaal in southern Africa (Peslier et al., 2010). At P greater than 5 GPa, the water contents of pyroxene remain relatively constant while those of olivine systematically decrease from 50 to less than 10 ppm H2O at 6.4 GPa. We hypothesized that at P greater than 6.4 GPa, i.e. at the bottom of the cratonic lithosphere, olivines are essentially dry (greater than 10 ppm H2O). As olivine likely controls the rheology of the mantle, we calculated that the dry olivines could be responsible for a contrast in viscosity between cratonic lithosphere and surrounding asthenosphere large enough to explain the resistance of cratonic root to asthenospheric delamination.

  8. Wireless model predictive control: Application to water-level system

    Directory of Open Access Journals (Sweden)

    Ramdane Hedjar

    2016-04-01

    Full Text Available This article deals with wireless model predictive control of a water-level control system. The objective of the model predictive control algorithm is to constrain the control signal inside saturation limits and maintain the water level around the desired level. Linear modeling of any nonlinear plant leads to parameter uncertainties and non-modeled dynamics in the linearized mathematical model. These uncertainties induce a steady-state error in the output response of the water level. To eliminate this steady-state error and increase the robustness of the control algorithm, an integral action is included in the closed loop. To control the water-level system remotely, the communication between the controller and the process is performed using radio channel. To validate the proposed scheme, simulation and real-time implementation of the algorithm have been conducted, and the results show the effectiveness of wireless model predictive control with integral action.

  9. Structure and stability of the water - graphite complexes

    Czech Academy of Sciences Publication Activity Database

    Rubeš, Miroslav; Nachtigall, Petr; Vondrášek, Jiří; Bludský, Ota

    2009-01-01

    Roč. 113, č. 19 (2009), s. 8412-8419 ISSN 1932-7447 R&D Projects: GA MŠk LC512; GA AV ČR IAA400550613 Institutional research plan: CEZ:AV0Z40550506 Keywords : water-graphite * DFT * coupled-cluster calculations * interaction energy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.224, year: 2009

  10. Effect of cooling water on stability of NLC linac components

    Energy Technology Data Exchange (ETDEWEB)

    F. Le Pimpec et al.

    2003-02-11

    Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.

  11. Effect of Cooling Water on Stability of NLC Linac Components

    Energy Technology Data Exchange (ETDEWEB)

    Le Pimpec, Frederic

    2002-11-01

    Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.

  12. Investigation the Stability of Treated Water Produced from Six Stations in Babylon

    Directory of Open Access Journals (Sweden)

    Hadeel Ali Abdulhussein

    2017-11-01

    Full Text Available Corrosion and scaling are mutual problems appeared in water distribution systems. The strictness of such problems depends on the quality of the water conveyed and the characteristics of the pipeline material. For solving and minimizing such problems, the probability of corrosivity and scaling of water as well as the factors effecting them should be investigated.  Four water stability indices (Langlier Saturation Index (LSI, Ryznar Stability Index (RSI, Pockurius Scaling Index (PSI, and Aggressive Index (AIwere used to investigate the stability of treated water from six selected water treatment plants in Babylon province (Al-Hillah Al-Jadeed, Al-Hillah Al-Kadeem, Al-Taiyara, Al-Hussain, Al-Mahaweel and Al-Hashmia during 2009-2013. According to LSI the treated water quality of the all stations was oversaturated with CaCO3 during the whole studied period (positive LSI values with a potential of forming a protective layer from calcium carbonate. RSI, PSI and AI results displayed that the water quality was of moderately corrosive which can be considered not harmful for water distribution systems.

  13. Levels of toxaphene congeners in fish from Danish waters

    DEFF Research Database (Denmark)

    Fromberg, Arvid; Cederberg, Tommy Licht; Hilbert, G.

    2000-01-01

    The levels of toxaphene congeners, in addition to PCB congeners and organochlorine pesticides, were determined in various fish samples from different Danish waters. While PCB-153 and p,p'-DDE show different levels depending on the fishing area, with highest levels in fish from the Western Baltic...... Sea, toxaphene was detected in all the samples investigated at a more constant level. The distribution of the three toxaphene congeners Parlar #26, #50 and #62 depends on the fishing area, with the Western Baltic Sea being different from the other waters by having almost equal levels of toxaphene...

  14. Auto Detection For High Level Water Content For Oil Well

    Science.gov (United States)

    Janier, Josefina Barnachea; Jumaludin, Zainul Arifin B.

    2010-06-01

    Auto detection of high level water content for oil well is a system that measures the percentage of water in crude oil. This paper aims to discuss an auto detection system for measuring the content of water level in crude oil which is applicable for offshore and onshore oil operations. Data regarding water level content from wells can be determined by using automation thus, well with high water level can be determined immediately whether to be closed or not from operations. Theoretically the system measures the percentage of two- fluid mixture where the fluids have different electrical conductivities which are water and crude oil. The system made use of grid sensor which is a grid pattern like of horizontal and vertical wires. When water occupies the space at the intersection of vertical and horizontal wires, an electrical signal is detected which proved that water completed the circuit path in the system. The electrical signals are counted whereas the percentage of water is determined from the total electrical signals detected over electrical signals provided. Simulation of the system using the MultiSIM showed that the system provided the desired result.

  15. Radar Based Flow and Water Level Forecasting in Sewer Systems

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Rasmussen, Michael R.; Grum, M.

    2009-01-01

    radar data and flow/water level model are continuously updated using online rain gauges and online in-sewer measurements, in order to make the best possible predictions. The project show very promising results, and show large potentials, exploiting the existing water infrastructure in future climate......This paper describes the first radar based forecast of flow and/or water level in sewer systems in Denmark. The rainfall is successfully forecasted with a lead time of 1-2 hours, and flow/levels are forecasted an additional ½-1½ hours using models describing the behaviour of the sewer system. Both...

  16. Nanometer patterning of water by tetraanionic ferrocyanide stabilized in aqueous nanodrops.

    Science.gov (United States)

    DiTucci, Matthew J; Williams, Evan R

    2017-02-01

    Formation of the small, highly charged tetraanion ferrocyanide, Fe(CN) 6 4- , stabilized in aqueous nanodrops is reported. Ion-water interactions inside these nanodrops are probed using blackbody infrared radiative dissociation, infrared photodissociation (IRPD) spectroscopy, and molecular modeling in order to determine how water molecules stabilize this highly charged anion and the extent to which the tetraanion patterns the hydrogen-bonding network of water at long distance. Fe(CN) 6 4- (H 2 O) 38 is the smallest cluster formed directly by nanoelectrospray ionization. Ejection of an electron from this ion to form Fe(CN) 6 3- (H 2 O) 38 occurs with low-energy activation, but loss of a water molecule is favored at higher energy indicating that water molecule loss is entropically favored over loss of an electron. The second solvation shell is almost complete at this cluster size indicating that nearly two solvent shells are required to stabilize this highly charged anion. The extent of solvation necessary to stabilize these clusters with respect to electron loss is substantially lower through ion pairing with either H + or K + ( n = 17 and 18, respectively). IRPD spectra of Fe(CN) 6 4- (H 2 O) n show the emergence of a free O-H water molecule stretch between n = 142 and 162 indicating that this ion patterns the structure of water molecules within these nanodrops to a distance of at least ∼1.05 nm from the ion. These results provide new insights into how water stabilizes highly charged ions and demonstrate that highly charged anions can have a significant effect on the hydrogen-bonding network of water molecules well beyond the second and even third solvation shells.

  17. Stability and dynamic performance of the General Electric Boiling Water Reactor. Licensing topical report

    International Nuclear Information System (INIS)

    1977-01-01

    The analytical methods used to evaluate the stability of GE boiling water reactors is presented. The physical and phenomenological characteristics pertinent to stability analyses are described for the following three configurations evaluated in the BWR design process: total plant, core, and channel hydrodynamic characteristics. Given is a description of the stability criteria and its theoretical basis followed by a description of the analytical methods used in evaluating the BWR. These analyses were derived from and supported by test data from current operating General Electric boiling water reactors. In addition, a parametric evaluation of the BWR is made for the total plant, reactor core, and channel hydrodynamic performance over a wide range of operating conditions. The information presented demonstrates the technical proficiency of the design and substantiates the operational stability characteristics of the integrated Nuclear Steam Supply System

  18. Sea Levels Online: Sea Level Variations of the United States Derived from National Water Level Observation Network Stations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water level records are a combination of the fluctuations of the ocean and the vertical land motion at the location of the station. Monthly mean sea level (MSL)...

  19. Identification of salivary proteins at oil-water interfaces stabilized by lysozyme and beta-lactoglobulin.

    Science.gov (United States)

    Silletti, Erika; Vitorino, Rui M P; Schipper, Raymond; Amado, Francisco M L; Vingerhoeds, Monique H

    2010-04-01

    In this research, we investigated the interaction occurring between oil-in-water emulsion droplets, stabilized by different emulsifiers, i.e. lysozyme and beta-lactoglobulin (beta-lg), and salivary proteins (SPs) with a molecular mass (M(r)) above about 10kDa. Different techniques, i.e. infrared spectroscopy, Western blotting, PAS staining and SDS-PAGE coupled to MS, were employed for this purpose. This study demonstrated the interaction between several salivary proteins and the emulsifiers at the oil-water interfaces. In particular, results show that the high M(r) mucin MUC5B was strongly bound to lysozyme stabilized emulsions, whereas beta-lg stabilized emulsions associated with MUC7 and, moderately, with MUC5B. Furthermore, we observed that salivary proteins in the range M(r) 10-100kDa associated differently with emulsion droplets. A large majority of SPs was found to interact with lysozyme stabilized emulsion droplets whilst in case of beta-lg stabilized emulsions, the SPs distribute more evenly between the fraction associated and non-associated with the droplets. A clear example is alpha-amylase (M(r) approximately 55kDa) which predominantly associates with lysozyme stabilized emulsion droplets, but not with beta-lg emulsion droplets. To conclude, our findings indicate that adsorption/association of salivary protein components onto the emulsion droplets is related to the type of emulsifying proteins at the oil-water interfaces and it is probably driven by the overall net charge at the droplet's oil-water interfaces, i.e. positive for lysozyme stabilized emulsions and negative for beta-lactoglobulin stabilized emulsion at neutral pH.

  20. Stability analysis of a simplified model of supercritical water-cooled system

    International Nuclear Information System (INIS)

    Xue Aijun; Cheng Xu

    2009-01-01

    This paper presents the stability analysis of a simplified model of supercritical water-cooled system. Based on the perturbation linearization and Laplace transformation, transfer function of the simplified system model is established. A stability map is generated using both dimensionless parameters, i.e. sub-pseudo-critical number and trans-pseudo-critical number. An unstable region nearby the pseudo-critical point is determined. The effect of some important parameters on the stability behavior is investigated. It is found that the system is stabilized with a higher hydraulic resistance of the inlet, fluid inlet velocity. It is also found that a longer heating zone or a bigger acceleration of gravity leads to a larger stability margin of the system. (authors)

  1. Modeling Nitrogen Decrease in Water Lettuce Ponds from Waste Stabilization Ponds

    Science.gov (United States)

    Putri, Gitta Agnes; Sunarsih

    2018-02-01

    This paper presents about the dynamic modeling of the Water Lettuce ponds as a form of improvement from the Water Hyacinth ponds. The purpose of this paper is to predict nitrogen decrease and nitrogen transformation in Water Lettuce ponds integrated with Waste Stabilization Ponds. The model consists of 4 mass balances, namely Dissolved Organic Nitrogen (DON), Particulate Organic Nitrogen (PON), ammonium (NH4+), Nitrate and Nitrite (NOx). The process of nitrogen transformation which considered in a Water Lettuce ponds, namely hydrolysis, mineralization, nitrification, denitrification, plant and bacterial uptake processes. Numerical simulations are performed by giving the values of parameters and the initial values of nitrogen compounds based on a review of previous studies. Numerical results show that the rate of change in the concentration of nitrogen compounds in the integration ponds of waste stabilization and water lettuce decreases and reaches stable at different times.

  2. Measurement of water potential in low-level waste management. [Shallow Land Burial

    Energy Technology Data Exchange (ETDEWEB)

    Jones, T. L.; Gee, G. W.; Kirkham, R. R.; Gibson, D. D.

    1982-08-01

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

  3. Stabilizing local boundary conditions for two-dimensional shallow water equations

    KAUST Repository

    Dia, Ben Mansour

    2018-03-27

    In this article, we present a sub-critical two-dimensional shallow water flow regulation. From the energy estimate of a set of one-dimensional boundary stabilization problems, we obtain a set of polynomial equations with respect to the boundary values as a requirement for the energy decrease. Using the Riemann invariant analysis, we build stabilizing local boundary conditions that guarantee the stability of the hydrodynamical state around a given steady state. Numerical results for the controller applied to the nonlinear problem demonstrate the performance of the method.

  4. Monitoring fire impacts in soil water repellency and structure stability during 6 years

    Directory of Open Access Journals (Sweden)

    A.J. Gordillo-Rivero

    2013-05-01

    Full Text Available Wildfires induce a series of soil changes affecting their physical and chemical properties and the hydrological and erosive response. Two of the properties that are commonly affected by burning are soil water repellency and structural stability. This paper carries out the study and monitoring of water repellency and soil structural stability during a period of 6 years after fire in calcareous soils of southern Spain in different aggregate size fractions (<2, 1-2, 0.5-1 and 0.25-0.5 mm. During this time, it was observed that both properties showed different tendencies in different aggregate size fractions. It was observed that water repellency increased after fire especially in the finer fractions (0.25-0.5 mm. Structural stability increased significantly after the fire and was progressively reduced during the experimental period.

  5. Thermodynamic stability and kinetic dissolution of perovskite in natural waters

    International Nuclear Information System (INIS)

    Nesbitt, H.W.; Bancroft, G.M.; Fyfe, W.S.; Karkhanis, S.; Melling, P.; Nishijima, A.

    1981-01-01

    Ringwood and coworkers have recently proposed using titanates and zirconates as hosts for nuclear waste in the Synroc B process. Three minerals are used as hosts: perovskite (CaTiO 3 ), Ba-hollandite (BaAl 2 Ti 6 O 16 ), and zirconolite (CaZrTi 2 O 7 ). The Synroc philosophy relies heavily on geological and geochemical observations in selecting stable host minerals. Although it has been recognized that the Synroc minerals are not thermodynamically compatible with siliceous rocks, the minerals are considered to be thermodynamically stable in the presence of water, and it has been reported that these minerals are kinetically stable under high-temperature (up to 900 0 C) hydrothermal conditions. Detailed thermodynamic calculations and leach tests have been performed which demonstrate: first, that perovskite is thermodynamically unstable in all known natural waters; and second, that pervoskite leaches at a significant rate even at 100 0 C. Hydrothermal leach tests have been made on natural and synthetic perovskite and perovskite analogues between 100 0 C and 300 0 C. Weight losses and solution concentrations were monitored. The results reported previously in the literature also show that perovskite is kinetically unstable in the presence of common silicates. Our results show that perovskite may be no more stable than siliceous glasses, such as rhyolite, which have been studied previously. Geologic evidence from common alkaline rocks also indicates that hollandite and zirconolite probably will not survive in common rock matrices

  6. Characterizing Structural Stability of Amyloid Motif Fibrils Mediated by Water Molecules.

    Science.gov (United States)

    Choi, Hyunsung; Chang, Hyun Joon; Lee, Myeongsang; Na, Sungsoo

    2017-04-05

    In biological systems, structural confinements of amyloid fibrils can be mediated by the role of water molecules. However, the underlying effect of the dynamic behavior of water molecules on structural stabilities of amyloid fibrils is still unclear. By performing molecular dynamics simulations, we investigate the dynamic features and the effect of interior water molecules on conformations and mechanical characteristics of various amyloid fibrils. We find that a specific mechanism induced by the dynamic properties of interior water molecules can affect diffusion of water molecules inside amyloid fibrils, inducing their different structural stabilities. The conformation of amyloid fibrils induced by interior water molecules show the fibrils' different mechanical features. We elucidate the role of confined and movable interior water molecules in structural stabilities of various amyloid fibrils. Our results offer insights not only in further understanding of mechanical features of amyloids as mediated by water molecules, but also in the fine-tuning of the functional abilities of amyloid fibrils for applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Development of Low-Toxicity Urine Stabilization for Spacecraft Water Recovery Systems

    Science.gov (United States)

    Adam, Niklas; Mitchell, Julie L.; Pickering, Karen D.

    2012-01-01

    Wastewater stabilization is an essential component of the spacecraft water cycle. The purpose of stabilizing wastewater is two-fold. First, stabilization prevents the breakdown of urea into ammonia, a toxic gas at high concentrations. Second, it prevents the growth of microorganisms, thereby mitigating hardware and water quality issues due to due biofilm and planktonic growth. Current stabilization techniques involve oxidizers and strong acids (pH=2) such as chromic and sulfuric acid, which are highly toxic and pose a risk to crew health. The purpose of this effort is to explore less toxic stabilization techniques, such as food-grade and commercial care preservatives. Additionally, certain preservatives were tested in the presence of a low-toxicity organic acid. Triplicate 300-mL volumes of urine were dosed with a predetermined quantity of stabilizer and stored for two weeks. During that time, pH, total organic carbon (TOC), ammonia, and turbidity were monitored. Those preservatives that showed the lowest visible microbial growth and stable pH were further tested in a six-month stability study. The results of the six-month study are also included in this paper.

  8. Development of Low-Toxicity Wastewater Stabilization for Spacecraft Water Recovery Systems

    Science.gov (United States)

    Adam, Niklas; Mitchell, Julie; Pickering, Karen; Carrier, Chris; Vega, Letty; Muirhead, Dean

    2014-01-01

    Wastewater stabilization was an essential component of the spacecraft water cycle. The purpose of stabilizing wastewater was two-fold. First, stabilization prevents the breakdown of urea into ammonia, a toxic gas at high concentrations. Second, it prevents the growth of microorganisms, thereby mitigating hardware and water quality issues due to due biofilm and planktonic growth. Current stabilization techniques involve oxidizers and strong acids (pH=2) such as chromic and sulfuric acid, which are highly toxic and pose a risk to crew health. The purpose of this effort was to explore less toxic stabilization techniques, such as food-grade and commercial care preservatives. Additionally, certain preservatives were tested in the presence of a low-toxicity organic acid. Triplicate 300-mL volumes of urine were dosed with a predetermined quantity of stabilizer and stored for two weeks. During that time, pH, total organic carbon (TOC), ammonia, and turbidity were monitored. Those preservatives that showed the lowest visible microbial growth and stable pH were further tested in a six-month stability study. The results of the six-month study are also included in this paper.

  9. Development of Low-Toxicity Wastewater Stabilization for Spacecraft Water Recovery Systems

    Science.gov (United States)

    Mitchell, Julie L.; Adam, Niklas; Pickering, Karen D.; Alvarez, Giraldo N.

    2015-01-01

    Wastewater stabilization was an essential component of the spacecraft water cycle. The purpose of stabilizing wastewater was two-fold. First, stabilization prevents the breakdown of urea into ammonia, a toxic gas at high concentrations. Second, it prevents the growth of microorganisms, thereby mitigating hardware and water quality issues due to due biofilm and planktonic growth. Current stabilization techniques involve oxidizers and strong acids (pH=2) such as chromic and sulfuric acid, which are highly toxic and pose a risk to crew health. The purpose of this effort was to explore less toxic stabilization techniques, such as food-grade and commercial care preservatives. Additionally, certain preservatives were tested in the presence of a low-toxicity organic acid. Triplicate 300-milliliter volumes of urine were dosed with a predetermined quantity of stabilizer and stored for two weeks. During that time, pH, total organic carbon (TOC), ammonia, and turbidity were monitored. Those preservatives that showed the lowest visible microbial growth and stable pH were further tested in a six-month stability study. The results of the six-month study are also included in this paper.

  10. Geomorphological evidence of water level changes in Nepenthes Mensae, Mars

    Science.gov (United States)

    de Pablo, Miguel Ángel; Pacifici, Andrea

    2008-08-01

    In the western sector of Nepenthes Mensae, Mars, there are some geomorphological features that could be related to a standing water sheet in the area, such as fluvial terraces, deltas and shorelines. A detailed analysis of these features reveals two variations in water level, probably related to tectonic processes, as suggested by the existence of a fissural volcano at this site.

  11. Typhoon and elevated radon level in a municipal water supply

    International Nuclear Information System (INIS)

    Mao, Cheng-Hsin; Weng, Pao-Shan

    2000-01-01

    The Municipal Water Supply at Hsinchu City is a water treatment plant using poly- aluminum chloride (PAC) for coagulation and then followed by precipitation and filtration. Its capacity is 70,000 m 3 /day. The raw water is drawn from the nearby river. Since the subject of interest is the radon level during typhoon season, the sampling period was from March to December 1999. Commercially available electret was used for water samples taken from the five ponds in the plant. This technique relies on the measurement of radon in air above a water sample enclosed in a sealed vessel. The concentration of airbone radon released from water was determined by means of the electret ion chamber. During the first sampling period there came two typhoons. One is called Magie during June 10-17, and the other called Sam during August 20-26. The first typhoon led to the radon level measured from the water samples as high as 705 Bq/m 3 , while the second caused even higher radon level as high as 772 Bq/m 3 . Similar results were obtained for the second sampling period after August till December 1999. For those measured without typhoon influence, the average radon was lower from the coagulation pond yet without coagulation process during March through August 1999. However, water samples taken from the pond after precipitation did not show similar results in radon level. (author)

  12. Determination of radionuclide levels in soil and water around ...

    African Journals Online (AJOL)

    The study of the radionuclide concentration levels in soil and water samples in Eagle, Atlas and rock cement companies in Port Harcourt was carried out. Soil and water samples collected from the respective premises were analyzed using the gamma -ray spectrometry. The average absorbed dose rates of the soil samples ...

  13. Carboxyhaemoglobin levels in water-pipe and cigarette smokers ...

    African Journals Online (AJOL)

    South African Medical Journal ... Water-pipe smoking is growing in popularity, especially among young people, because of the social nature of the smoking session and the assumption that the ... We aimed to measure carboxyhaemoglobin (COHb) blood levels before and after water-pipe and cigarette smoking sessions.

  14. Socio–economic benefits and pollution levels of water resources ...

    African Journals Online (AJOL)

    Communities are dependent on wetlands resources for income generation. However, anthropogenic activities that result into pollution of water are one of the major public health problems. Assessment of socio–economic activities and pollution levels of domestic water sources in Gulu Municipality, Pece wetland was done.

  15. Arsenic contamination levels in drinking water sources in mining ...

    African Journals Online (AJOL)

    Arsenic contamination in drinking water is a public health problem all over the World especially in mining areas. The study herein reported assessed the concentration levels of arsenic in some drinking water sources in the mining areas in the Lake Victoria Basin and investigated the potential for its removal by adsorption ...

  16. NOS CO-OPS Water Level Data, Verified, Hourly

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has verified (quality-controlled), hourly, water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS)....

  17. NOS CO-OPS Water Level Data, Verified, High Low

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has verified (quality-controlled), daily, high low water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and Services...

  18. NOS CO-OPS Water Level Data, Preliminary, 1-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has recent, preliminary (not quality-controlled), 1-minute, water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and...

  19. NOS CO-OPS Water Level Data, Preliminary, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has recent, preliminary (not quality-controlled), 6-minute, water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and...

  20. NOS CO-OPS Water Level Data, Verified, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has verified (quality-controlled), 6-minute, water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS)....

  1. Trace-level mercury removal from surface water

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  2. Predictors of Placement Stability at the State Level: The Use of Logistic Regression to Inform Practice

    Science.gov (United States)

    Courtney, Jon R.; Prophet, Retta

    2011-01-01

    Placement instability is often associated with a number of negative outcomes for children. To gain state level contextual knowledge of factors associated with placement stability/instability, logistic regression was applied to selected variables from the New Mexico Adoption and Foster Care Administrative Reporting System dataset. Predictors…

  3. LONG TERM STABILITY STUDY AT FNAL AND SLAC USING BINP DEVELOPED HYDROSTATIC LEVEL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Seryi, Andrei

    2003-05-28

    Long term ground stability is essential for achieving the performance goals of the Next Linear Collider. To characterize ground motion on relevant time scales, measurements have been performed at three geologically different locations using a hydrostatic level system developed specifically for these studies. Comparative results from the different sites are presented in this paper.

  4. Negotiating water across levels: A peace and conflict "Toolbox" for water diplomacy

    Science.gov (United States)

    Grech-Madin, Charlotte; Döring, Stefan; Kim, Kyungmee; Swain, Ashok

    2018-04-01

    As a key policy tool, water diplomacy offers greater political engagement in the cooperative management of shared water. A range of initiatives has been dedicated to this end, almost invariably oriented around the interactions of nation states. Crucially, however, practitioners of water diplomacy also need to address water governance at sub-state levels. As a political, multi-level, and normative field, peace and conflict research offers a pluralism of approaches designed to bring actors together at all levels. Drawing upon this research, this paper offers new focal points for water diplomacy that can enhance its policy effectiveness and enrich its underlying academic current. More specifically, it presents three hitherto undervalued tools for water diplomacy: at the interstate level, to uncover the rich body of political norms that bind states to shared understandings of acceptable practice around water. At the intrastate level, to incorporate ethnography of water users and civil society groups' responses to state-led waterworks projects, and at the communal level to employ disaggregated georeferenced data on water resources in conflict-prone areas. Taken together, these analytical tools provide a multi-faceted political gauge of the dynamics of water diplomacy, and add vital impetus to develop water diplomacy across multiple levels of policy engagement.

  5. Oil-in-water Pickering emulsions stabilized by colloidal particles from the water-insoluble protein zein

    NARCIS (Netherlands)

    de Folter, J.W.J.; van Ruijven, M.W.M.; Velikov, K.

    2012-01-01

    Few fully natural and biocompatible materials are available for the effective particle-stabilization of emulsions since strict requirements, such as insolubility in both fluid phases and intermediate wettability, need to be met. In this paper, we demonstrate the first use of water-insoluble

  6. Radium-226 levels in Italian drinking waters and foods

    International Nuclear Information System (INIS)

    Mastinu, G.G.; Santaroni, G.P.

    1980-01-01

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

  7. Separating decadal global water cycle variability from sea level rise.

    Science.gov (United States)

    Hamlington, B D; Reager, J T; Lo, M-H; Karnauskas, K B; Leben, R R

    2017-04-20

    Under a warming climate, amplification of the water cycle and changes in precipitation patterns over land are expected to occur, subsequently impacting the terrestrial water balance. On global scales, such changes in terrestrial water storage (TWS) will be reflected in the water contained in the ocean and can manifest as global sea level variations. Naturally occurring climate-driven TWS variability can temporarily obscure the long-term trend in sea level rise, in addition to modulating the impacts of sea level rise through natural periodic undulation in regional and global sea level. The internal variability of the global water cycle, therefore, confounds both the detection and attribution of sea level rise. Here, we use a suite of observations to quantify and map the contribution of TWS variability to sea level variability on decadal timescales. In particular, we find that decadal sea level variability centered in the Pacific Ocean is closely tied to low frequency variability of TWS in key areas across the globe. The unambiguous identification and clean separation of this component of variability is the missing step in uncovering the anthropogenic trend in sea level and understanding the potential for low-frequency modulation of future TWS impacts including flooding and drought.

  8. Transient response of Salix cuttings to changing water level regimes

    Science.gov (United States)

    Gorla, L.; Signarbieux, C.; Turberg, P.; Buttler, A.; Perona, P.

    2015-03-01

    Sustainable water management requires an understanding of the effects of flow regulation on riparian ecomorphological processes. We investigated the transient response of Salix viminalis by examining the effect of water-level regimes on its above-ground and below-ground biomass. Four sets of Salix cuttings, three juveniles (in the first growing season) and one mature (1 year old), were planted and initially grown under the same water-level regime for 1 month. We imposed three different water-level regime treatments representing natural variability, a seasonal trend with no peaks, and minimal flow (characteristic of hydropower) consisting of a constant water level and natural flood peaks. We measured sap flux, stem water potential, photosynthesis, growth parameters, and final root architecture. The mature cuttings were not affected by water table dynamics, but the juveniles displayed causal relationships between the changing water regime, plant growth, and root distribution during a 2 month transient period. For example, a 50% drop in mean sap flux corresponded with a -1.5 Mpa decrease in leaf water potential during the first day after the water regime was changed. In agreement with published field observations, the cuttings concentrated their roots close to the mean water table of the corresponding treatment, allowing survival under altered conditions and resilience to successive stress events. Juvenile development was strongly impacted by the minimum flow regime, leading to more than 60% reduction of both above-ground and below-ground biomass, with respect to the other treatments. Hence, we suggest avoiding minimum flow regimes where Salix restoration is prioritized.

  9. Conductometric method for determining water stability and nutrient leaching of extruded fish feed

    Directory of Open Access Journals (Sweden)

    Banjac Vojislav V.

    2017-01-01

    Full Text Available Water stability of eight samples of extruded salmon feeds was first determined by applying two gravimetric methods developed by the authors: gravimetric static and wet sieving method. Then, the conductometric method, primarily developed for investigation of nutrient leaching of feed into the water by the authors, was used for each sample. The aim of this study was to evaluate the potential of the conductometric measurement as a technique for determining water stability of extruded fish feed. In order to find any correlation between the results of two gravimetric tests and conductometric method, correlation analysis was employed. The results of static and wet sieving method were expressed as water stability index, which was expressed as the percent of remained dry matter of sample after being disintegrated in the water. The results of conductometric method were shown as conductivity curves for each sample, giving the insight in rate of nutrient leaching during the time. The obtained values of water conductivity showed no significant (p < 0.05 correlation with the results of static water method, while there was a negative significant (p < 0.05 correlation with the results of wet sieving method during first four hours of pellets soaking in water. The highest correlation coefficients were obtained within the first hour of conductivity measurement, demonstrating that proposed conductometric method had a potential to be applied as a rapid and simple method for determination and relative comparison of salmon feed water stability.[ Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III46012 and Grant no. TR31011

  10. Color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for non metal clasp denture.

    Science.gov (United States)

    Jang, Dae-Eun; Lee, Ji-Young; Jang, Hyun-Seon; Lee, Jang-Jae; Son, Mee-Kyoung

    2015-08-01

    The aim of this study was to compare the color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for the non-metal clasp dentures to those of thermoplastic polyamide and conventional heat-polymerized denture base resins. Three types of denture base resin, which are conventional heat-polymerized acrylic resin (Paladent 20), thermoplastic polyamide resin (Bio Tone), thermoplastic acrylic resin (Acrytone) were used as materials for this study. One hundred five specimens were fabricated. For the color stability test, specimens were immersed in the coffee and green tee for 1 and 8 weeks. Color change was measured by spectrometer. Water sorption was tested after 1 and 8 weeks immersion in the water. For the test of cytotoxicity, cell viability assay was measured and cell attachment was analyzed by FE-SEM. All types of denture base resin showed color changes after 1 and 8 weeks immersion. However, there was no significant difference between denture base resins. All specimens showed significant color changes in the coffee than green tee. In water sorption test, thermoplastic acrylic resin showed lower values than conventional heat-polymerized acrylic resin and thermoplastic polyamide resin. Three types of denture base showed low cytotoxicity in cell viability assay. Thermoplastic acrylic resin showed the similar cell attachment but more stable attachment than conventional heat-polymerized acrylic resin. Thermoplastic acrylic resin for the non-metal clasp denture showed acceptable color stability, water sorption and cytotoxicity. To verify the long stability in the mouth, additional in vitro studies are needed.

  11. Hydraulic Properties of Porous Media Saturated with Nanoparticle-Stabilized Air-Water Foam

    Directory of Open Access Journals (Sweden)

    Xianglei Zheng

    2016-12-01

    Full Text Available The foam generated by the mixture of air and water has a much higher viscosity and lower mobility than those of pure water or gas that constitutes the air-water foam. The possibility of using the air-water foam as a flow barrier for the purpose of groundwater and soil remediation is explored in this paper. A nanoparticle-stabilized air-water foam was fabricated by vigorously stirring the nano-fluid in pressurized condition. The foam bubble size distribution was analyzed with a microscope. The viscosities of foams generated with the solutions with several nanoparticle concentrations were measured as a function of time. The breakthrough pressure of foam-saturated microfluidic chips and sand columns were obtained. The hydraulic conductivity of a foam-filled sand column was measured after foam breakthrough. The results show that: (1 bubble coalescence and the Ostwald ripening are believed to be the reason of bubble size distribution change; (2 the viscosity of nanoparticle-stabilized foam and the breakthrough pressures decreased with time once the foam was generated; (3 the hydraulic conductivity of the foam-filled sand column was almost two orders of magnitude lower than that of a water-saturated sand column even after the foam-breakthrough. Based on the results in this study, the nanoparticle-stabilized air-water foam could be injected into contaminated soils to generate vertical barriers for temporary hydraulic conductivity reduction.

  12. Determination of Heavy Metal Levels in Various Industrial Waste Waters

    Directory of Open Access Journals (Sweden)

    Mustafa Şahin Dündar

    2012-06-01

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

  13. The stability of drinking water treatment residue with ozone treatment.

    Science.gov (United States)

    Liu, Xin; Wu, Yu; He, Rui; Jiang, He-Long; Wang, Changhui

    2017-06-12

    The best management of drinking water treatment residue (DWTR) in environmental remediation should be based on comprehensively understanding the effectiveness and risk of DWTR. In this study, the variation in physicochemical properties, metal lability, and adsorption capability of DWTR under oxidizing condition were investigated. The oxidizing condition was set up using ozone treatment, and the laboratory incubation test were performed within 50 d in association with thermogravimetry, Fourier Transform Infrared Spectrometry, specific surface area and porosity analyzer, fractionation, and P adsorption test. The results showed that ozone treatment had limited effect on the properties of organic matter, the lability of Al, Cu, and Fe, the P adsorption capability, and the distributions of the adsorbed P in DWTR, but the treatment increased N 2 sorption/desorption, specific surface area, total pore volume of DWTR and led to the transformation of Mn from acid-soluble to reducible fractions. These findings demonstrated that DWTR generally kept stable under oxidizing environment; even oxidizing environment may induce a tendency of increasing the adsorption capability and decreasing the environmental risk of DWTR. Accordingly, the effectiveness and safety of DWTR can be maintained under natural aerobic environment, and DWTR is a reliable adsorbent that could be recycled in environmental remediation.

  14. Water resources data for Virginia, water year 1991. Volume 2. Ground-water-level and ground-water-quality records. Water-data report (Annual), 1 October 1991-30 September 1992

    International Nuclear Information System (INIS)

    Prugh, B.J.; Powell, E.D.

    1993-01-01

    Water-resources data for the 1992 water year for Virginia consist of records of water levels and water quality of ground-water wells. The report (Volume 2. Ground-Water-Level and Ground-Water-Quality Records) contains water levels at 356 observation wells and water quality at 2 wells. Locations of these wells are given in the report

  15. The stability of water-in-crude and model oil emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, A.P.; Zaki, N.N.; Kilpatrick, P.K. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical Engineering; Sjoblom, J. [Norwegian Univ. of Science and Technology, Trondheim (Norway). Dept. of Chemical Engineering, Ugelstad Laboratory

    2007-12-15

    Emulsions are among the most persistent problems faced by petroleum producers. Water is added at refineries to generate a large oil-water interfacial area to facilitate the extraction of salts from the crude oil. The produced emulsions do not readily resolve into neat crude and water phases, and some volume of the emulsion remains. This paper described the surface-active components in petroleum as well as methods of measuring emulsion stability. The stabilities of a variety of water-in-model oil and petroleum emulsions were measured using the critical electric field (CEF) technique. In this study, CEF was used to measure the stability of water-in-heptane-toluene-asphaltene emulsions. Results for emulsions with 60 and 30 per cent water were presented. The effect of interfacial film thickness was discussed and a kinetic model for interfacial film formation was presented. The importance of solvation of asphaltenes to emulsion stability was confirmed along with the importance of the state of asphaltene aggregation. It was shown that emulsion stability increased with the concentration of soluble asphaltenes near the point of precipitation. In order to calculate interfacial area and film thickness, optical microscopy was used to measure droplet size. Film thickness increased with asphaltene concentration up to the solubility limit. Increased concentration above that limit had little effect. CEF increased with interfacial film thickness up to a monolayer coverage of asphaltene aggregates, but film thickness had a much smaller effect above the monolayer. These results were used to develop correlations of the stability of water-in-crude oil emulsions. A strong correlation was found for CEF with the product of asphaltene concentration and the difference in hydrogen to carbon atomic ratios of the asphaltenes and petroleum solvent. The effects of asphaltene chemistry, solvency, and resin concentration on the adsorption and consolidation of emulsion stabilizing interfacial

  16. Global Gray Water Footprint and Water Pollution Levels Related to Anthropogenic Nitrogen Loads to Fresh Water.

    Science.gov (United States)

    Mekonnen, Mesfin M; Hoekstra, Arjen Y

    2015-11-03

    This is the first global assessment of nitrogen-related water pollution in river basins with a specification of the pollution by economic sector, and by crop for the agricultural sector. At a spatial resolution of 5 by 5 arc minute, we estimate anthropogenic nitrogen (N) loads to freshwater, calculate the resultant gray water footprints (GWFs), and relate the GWFs per river basin to runoff to calculate the N-related water pollution level (WPL) per catchment. The accumulated global GWF related to anthropogenic N loads in the period 2002-2010 was 13×10(12) m3/y. China contributed about 45% to the global total. Three quarters of the GWF related to N loads came from diffuse sources (agriculture), 23% from domestic point sources and 2% from industrial point sources. Among the crops, production of cereals had the largest contribution to the N-related GWF (18%), followed by vegetables (15%) and oil crops (11%). The river basins with WPL>1 (where the N load exceeds the basin's assimilation capacity), cover about 17% of the global land area, contribute about 9% of the global river discharge, and provide residence to 48% of the global population.

  17. A comparison of solidification media for the stabilization of low- level radioactive wastes

    International Nuclear Information System (INIS)

    Cowgill, M.G.

    1991-10-01

    When requirements exist to stabilize low-level radioactive waste (LLW) prior to disposal, efforts to achieve this stability often center on the mixing of the waste with a solidification medium. Although historically the medium of choice has been based on the use of portland cement as the binder material, several other options have been developed and subsequently implemented. These include thermoplastic polymers, thermosetting polymers and gypsum. No one medium has thus far been successful in providing stability to all forms of LLW. The characteristics and attributes of these different binder materials are reviewed and compared. The aspects examined include availability of information, limitations to use, sensitivity to process or waste chemistry changes, radionuclide retention ability, modeling of radionuclide release processes, ease and safety of use, and relative costs

  18. Impact of high level penetration of Wind Turbines on Power System Transient Stability

    DEFF Research Database (Denmark)

    Kalogiannis, Theodoros; Llano, Enrique Muller; Hoseinzadeh, Bakhtyar

    2015-01-01

    One of the most relevant aspects in power systems is their reliability and robustness of maintaining the stability under large disturbances. System stability is a crucial aspect to consider when expanding the network, e.g. while increasing the levels of wind power penetration. Wind turbine...... generators differ from the conventional ones in their inertial contribution to the grid, therefore, in most cases the ability of the system to maintain a stable operation is declined. To investigate this, two standard models are designed in PowerFactory software. The first is used to characterize system...... components, the response of the wind turbines and thereupon to validate them, whereas the second is used to estimate the maximum levels of wind power penetration. Those levels mainly depend on the spinning reserve, the inertia of the system and the severity of the event. Rate of change of frequency...

  19. Water quality characteristics and pollution levels of heavy metals in ...

    African Journals Online (AJOL)

    The main aim of this study was to assess the level of water quality of Lake Haiq, Ethiopia with respect to selected physical ... gated using standard analytical procedures. the level of the studied heavy metals (Pb, Cd, Cu and Zn) was determined using the .... no known discharge and hence used as reference site. Sampling ...

  20. Levels of Cadmium in Soil, Sediment and Water Samples from ...

    African Journals Online (AJOL)

    Soil, sediment and water samples collected from the catchment areas of some selected rivers and streams in Tarkwa and its environs were investigated for the levels of cadmium using the Atomic Absorption spectrophometric technique. From the results, it was observed that cadmium levels were generally higher than the ...

  1. Estimation Of Height Of Oil -Water Contact Above Free Water Level ...

    African Journals Online (AJOL)

    An estimate of oil-water contact (OWC) and the understanding of the capillary behaviour of hydrocarbon reservoirs are vital for optimum reservoir characterization, hydrocarbon exploration and production. Hence, the height of oil-water contact above free water level for different rock types from some Niger Delta reservoirs ...

  2. Stability of streambanks formed in partially saturated soils and effects of negative pore water pressures: the Sieve River (Italy)

    Science.gov (United States)

    Rinaldi, Massimo; Casagli, Nicola

    1999-01-01

    Streambanks of alluvial channels are usually composed of loose materials, which are unsaturated in ambient conditions. Unsaturated soils are subject to negative pore water pressures, which cause an apparent cohesion. The latter is the main factor in allowing the stability of near-vertical banks. Even during moderate in-bank flow events, the apparent cohesion can be strongly reduced as the material approaches full saturation; therefore, during the drawdown phase, as the confining pressure of the water in the channel disappears, a bank failure is likely to occur. Channel bed-level lowering along the Sieve River, Central Italy, has caused widespread bank instability. A geomorphological reconnaissance of forms and processes was followed by in situ tests to determine the shear strength of the banks. Interpretation of the tests and a streambank stability analysis were based on concepts of soil mechanics for unsaturated soils, in order to obtain relations between bank angle and height in limit equilibrium conditions. A stability chart was obtained with curves for different apparent cohesion values, and a stability analysis was performed taking into account the effects of flow events. In order to investigate the pore pressure effects, a series of piezo-tensiometers were installed in a streambank of the Sieve River. Data from a 1 year monitoring period show variations in pore water pressure and matric suction as a consequence of rainfall, evapotranspiration, and water stage variations. A planar failure with a tension crack occurred in the upper cohesive part of the bank during December 1996. The safety factor has been expressed as a function of the geometry of the bank and of the shear strength of the material. Safety factor variations through time are therefore shown as a function of seasonal variations in matric suction.

  3. [Fluoride levels in commercial dentifrices and drinking water in Algeria].

    Science.gov (United States)

    Merghache, D; Bellout, B; Merghache, S; Boucherit-Atmani, Z

    2011-12-01

    More and more scientific evidence show that fluorides have a cariostatic action to the plaque-saliva-tooth interface during cariogenous dissolution. Fluorides slow down demineralization and enhance remineralization. Their action is optimal, in the oral environment, when used at low concentrations on a continuous basis. The use of the fluorinated toothpastes during brushing of the teeth is a simple, rational method of daily topics application of fluorine, largely used in the context of prevention of dental caries and which can even be regarded as a public health measure. The water ingestion fluorinated represents itself an excellent average of the local application of fluorine. Our work concerned a quantitative study of fluorine in toothpaste and drinking water, and comparative between the local product and the imported one for the toothpastes, and the mineral water and public supply. The standard method of fluorine based on the potentiometry and distillation has shown that 50% of the tested toothpastes contain adequate concentration so that a product of dental care fights against decay. The Tlemcen tap water contains acceptable fluorine content, but the mineral water, with an excessive contribution, can cause fluorose. Of this, we can deduce that a topical application of a suitable quantity of fluorine on a daily basis in accordance with the precautions is not only the prevention of dental caries, but also to stabilize it if it already exists.

  4. Physical Stability of Oil in Water Emulsions in the Presence of Gamma Irradiated Gum Tragacanth

    DEFF Research Database (Denmark)

    Meybodi, Neda Mollakhalili; Mohammadifar, Mohammad Amin; Farhoodi, Mehdi

    2017-01-01

    Gum tragacanth (GT) exuded from an Iranian Astragalus species was γ-irradiated at 0, 0.75, 1.5, 3, 5, 7, 10 kGy and used to stabilize a model oil in water emulsion system. Stability and physicochemical properties of emulsion samples were investigated with respect to the effect of irradiation....... Emulsions were prepared by homogenizing 10% w/w sun flower oil with 90% w/w aqueous gum dispersions and stored quiescently at 25°C for 120 days. Results indicated that using 1.5 kGy irradiated GT was more effective in providing optimum values of apparent viscosity, number mean diameter, electrosteric...... repulsion and structure strength for getting maximum emulsion stability. GT significantly reduced the interfacial tension of the oil and water system, but no significant differences were observed among all irradiation treated and non-irradiated samples. This study revealed that, GT acts as a bifunctional...

  5. Luminosity control and beam orbit stability with beta star leveling at LHC and HL-LHC

    CERN Document Server

    Gorzawski, Arkadiusz Andrzej; Wenninger, Jorg

    This thesis describes the wide subject of the luminosity leveling and its requirements for the LHC and the HL-LHC. We discuss the advantages and disadvantages of different leveling methods focusing the thesis on the beta star leveling technique. We review the beams offset build--up due to the environmental (i.e. natural ground motion) and mechanical (i.e. moving quadrupole) sources. We quantify the instrumentation requirements for the reliable and reproducible operation with small offsets at the interaction points. Last but not least, we propose a novel method for the beam offset stabilization at the collision point based on the feedback from the luminosity.

  6. Trophic level stability-inducing effects of predaceous early juvenile fish in an estuarine mesocosm study.

    Science.gov (United States)

    Wasserman, Ryan J; Noyon, Margaux; Avery, Trevor S; Froneman, P William

    2013-01-01

    Classically, estuarine planktonic research has focussed largely on the physico-chemical drivers of community assemblages leaving a paucity of information on important biological interactions. Within the context of trophic cascades, various treatments using in situ mesocosms were established in a closed estuary to highlight the importance of predation in stabilizing estuarine plankton abundances. Through either the removal (filtration) or addition of certain planktonic groups, five different trophic systems were established. These treatments contained varied numbers of trophic levels and thus different "predators" at the top of the food chain. The abundances of zooplankton (copepod and polychaete), ciliate, micro-flagellate, nano-flagellate and bacteria were investigated in each treatment, over time. The reference treatment containing apex zooplanktivores (early juvenile mullet) and plankton at natural densities mimicked a natural, stable state of an estuary. Proportional variability (PV) and coefficient of variation (CV) of temporal abundances were calculated for each taxon and showed that apex predators in this experimental ecosystem, when compared to the other systems, induced stability. The presence of these predators therefore had consequences for multiple trophic levels, consistent with trophic cascade theory. PV and CV proved useful indices for comparing stability. Apex predators exerted a stabilizing pressure through feeding on copepods and polychaetes which cascaded through the ciliates, micro-flagellates, nano-flagellates and bacteria. When compared with treatments without apex predators, the role of predation in structuring planktonic communities in closed estuaries was highlighted.

  7. Trophic level stability-inducing effects of predaceous early juvenile fish in an estuarine mesocosm study.

    Directory of Open Access Journals (Sweden)

    Ryan J Wasserman

    Full Text Available Classically, estuarine planktonic research has focussed largely on the physico-chemical drivers of community assemblages leaving a paucity of information on important biological interactions.Within the context of trophic cascades, various treatments using in situ mesocosms were established in a closed estuary to highlight the importance of predation in stabilizing estuarine plankton abundances. Through either the removal (filtration or addition of certain planktonic groups, five different trophic systems were established. These treatments contained varied numbers of trophic levels and thus different "predators" at the top of the food chain. The abundances of zooplankton (copepod and polychaete, ciliate, micro-flagellate, nano-flagellate and bacteria were investigated in each treatment, over time. The reference treatment containing apex zooplanktivores (early juvenile mullet and plankton at natural densities mimicked a natural, stable state of an estuary. Proportional variability (PV and coefficient of variation (CV of temporal abundances were calculated for each taxon and showed that apex predators in this experimental ecosystem, when compared to the other systems, induced stability. The presence of these predators therefore had consequences for multiple trophic levels, consistent with trophic cascade theory.PV and CV proved useful indices for comparing stability. Apex predators exerted a stabilizing pressure through feeding on copepods and polychaetes which cascaded through the ciliates, micro-flagellates, nano-flagellates and bacteria. When compared with treatments without apex predators, the role of predation in structuring planktonic communities in closed estuaries was highlighted.

  8. Calculated Pourbaix Diagrams of Cubic Perovskites for Water Splitting: Stability Against Corrosion

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; Thygesen, Kristian Sommer; Jacobsen, Karsten Wedel

    2014-01-01

    We use density functional theory calculations to investigate the stability of cubic perovskites for photo-electrochemical water splitting taking both materials in their bulk crystal structure and dissolved phases into account. The method is validated through a detailed comparison of the calculated...

  9. Identification of salivary proteins at oil–water interfaces stabilized by lysozyme and ß-lactoglobulin

    NARCIS (Netherlands)

    Silletti, E.; Vitorino, R.M.P.; Schipper, R.G.; Amado, F.M.L.; Vingerhoeds, M.H.

    2010-01-01

    In this research, we investigated the interaction occurring between oil-in-water emulsion droplets, stabilized by different emulsifiers, i.e. lysozyme and ß-lactoglobulin (ß-lg), and salivary proteins (SPs) with a molecular mass (Mr) above about 10 kDa. Different techniques, i.e. infrared

  10. Experimental and numerical stability investigations on natural circulation boiling water reactors

    NARCIS (Netherlands)

    Marcel, C.P.

    2007-01-01

    The stability of natural circulation boiling water reactors is investigated with a strong emphasis on experiments. Two different facilities are used for such a task: the GENESIS facility (to which a void reactivity feedback system is artificially added) and the CIRCUS facility. In addition,

  11. Hydrolytic stability of water-soluble spruce O-acetyl galactoglucomannans

    NARCIS (Netherlands)

    Xu, C.; Pranovich, A.; Hemmimg, J.; Holmbom, B.; Albrecht, S.A.; Schols, H.A.; Willfor, S.

    2009-01-01

    Water-soluble native O-acetyl galactoglucomannan (GGM) from spruce is a polysaccharide that can be produced in an industrial scale. To develop GGM applications, information is needed on its stability, particularly under acidic conditions. Therefore, acid hydrolysis of spruce GGM was investigated at

  12. Stability and bandgaps of layered perovskites for one- and two-photon water splitting

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; García Lastra, Juan Maria; Hüser, Falco

    2013-01-01

    in the Ruddlesden–Popper phase of the layered perovskite structure. Based on screening criteria for the stability, bandgaps and band edge positions, we suggest 20 new materials for the light harvesting photo-electrode of a one-photon water splitting device and 5 anode materials for a two-photon device with silicon...

  13. A comparison of water-based and land-based core stability exercises in patients with lumbar disc herniation: a pilot study.

    Science.gov (United States)

    Bayraktar, Deniz; Guclu-Gunduz, Arzu; Lambeck, Johan; Yazici, Gokhan; Aykol, Sukru; Demirci, Harun

    2016-01-01

    To determine and compare the effects of core stability exercise programs performed in two different environments in lumbar disc herniation (LDH) patients. Thirty-one patients who were diagnosed with LDH and were experiencing pain or functional disability for at least 3 months were randomly divided into two groups as land-based exercises or water specific therapy. Also, 15 age-sex-matched healthy individuals were recruited as healthy controls. Both groups underwent an 8-week (3 times/week) core stabilization exercise program. Primary outcomes were pain, trunk muscle static endurance and perceived disability level. The secondary outcome was health-related quality of life. Level of static endurance of trunk muscles was found to be lower in the patients compared to the controls at baseline (p 0.05). After the treatment, static endurance of trunk muscles of the LDH patients became similar to controls (p > 0.05). According to these results, core stabilization exercise training performed on land or in water both could be beneficial in LDH patients and there is no difference between the environments. An 8-week core stabilization program performed in water or on land decrease pain level and improve functional status in LDH patients. Both programs seem beneficial to increase health-related quality of life and static endurance of trunk muscles. Core stability exercises could be performed in water as well, no differences were found between methods due to environment.

  14. Level of anxiety as one of the criteria of efficiency of emotional stability in sport dancing

    Directory of Open Access Journals (Sweden)

    Y.S. Ermolaeva

    2015-02-01

    Full Text Available Purpose: improve the efficiency of performance of competitive sports dance in pairs due to the formation and improvement of indicators of emotional stability. The objectives of the study was to examine the personality characteristics of athletes in the dance couple, affecting their emotional stability. Also determine the conditions for the formation of emotional stability dancing. Material : the study involved 32 dancers aged 12-14 years old. Spielberger questionnaire was used. Results : it was found that the level of trait anxiety was 40.2 points. Athletes also met with high and low trait anxiety. The average level of situational anxiety at rest the dancers stood at 38.8 points. Before the tournament, this index increased significantly (54.5 points. Conclusions : for dancers with a high level of anxiety should generate a sense of confidence and success in their abilities. For dancers with low levels of anxiety requires waking activity, arousal of interest, a sense of responsibility in the task of training activity.

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

    Science.gov (United States)

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

    2012-12-21

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

  16. Representative locations from time series of soil water content using time stability and wavelet analysis.

    Science.gov (United States)

    Rivera, Diego; Lillo, Mario; Granda, Stalin

    2014-12-01

    The concept of time stability has been widely used in the design and assessment of monitoring networks of soil moisture, as well as in hydrological studies, because it is as a technique that allows identifying of particular locations having the property of representing mean values of soil moisture in the field. In this work, we assess the effect of time stability calculations as new information is added and how time stability calculations are affected at shorter periods, subsampled from the original time series, containing different amounts of precipitation. In doing so, we defined two experiments to explore the time stability behavior. The first experiment sequentially adds new data to the previous time series to investigate the long-term influence of new data in the results. The second experiment applies a windowing approach, taking sequential subsamples from the entire time series to investigate the influence of short-term changes associated with the precipitation in each window. Our results from an operating network (seven monitoring points equipped with four sensors each in a 2-ha blueberry field) show that as information is added to the time series, there are changes in the location of the most stable point (MSP), and that taking the moving 21-day windows, it is clear that most of the variability of soil water content changes is associated with both the amount and intensity of rainfall. The changes of the MSP over each window depend on the amount of water entering the soil and the previous state of the soil water content. For our case study, the upper strata are proxies for hourly to daily changes in soil water content, while the deeper strata are proxies for medium-range stored water. Thus, different locations and depths are representative of processes at different time scales. This situation must be taken into account when water management depends on soil water content values from fixed locations.

  17. Influence of Water Content on the β-Sheet Formation, Thermal Stability, Water Removal, and Mechanical Properties of Silk Materials.

    Science.gov (United States)

    Yazawa, Kenjiro; Ishida, Kana; Masunaga, Hiroyasu; Hikima, Takaaki; Numata, Keiji

    2016-03-14

    Silk, which has excellent mechanical toughness and is lightweight, is used as a structural material in nature, for example, in silkworm cocoons and spider draglines. However, the industrial use of silk as a structural material has garnered little attention. For silk to be used as a structural material, its thermal processability and associated properties must be well understood. Although water molecules influence the glass transition of silk, the effects of water content on the other thermal properties of silks are not well understood. In this study, we prepared Bombyx mori cocoon raw fibers, degummed fibers, and films with different water contents and then investigated the effects of water content on crystallization, degradation, and water removal during thermal processing. Thermal gravimetric analyses of the silk materials showed that water content did not affect the thermal degradation temperature but did influence the water removal behavior. By increasing the water content of silk, the water molecules were removed at lower temperatures, indicating that the amount of free water in silk materials increased; additionally, the glass transition temperature decreased with increasing water plasticization. Differential scanning calorimetry and wide-angle X-ray scattering of the silk films also suggested that the water molecules in the amorphous regions of the silk films acted as a plasticizer and induced β-sheet crystallization. The plasticizing effect of water was not detected in silk fibers, owing to their lower amorphous content and mobility. The structural and mechanical characterizations of the silk films demonstrated the silk film prepared at RH 97% realized both crystallinity and ductility simultaneously. Thus, the thermal stability, mechanical, and other properties of silk materials are regulated by their water content and crystallinity.

  18. Physical characteristics of the coastal waters between Navapur and Umbharat, West coast of India. Part 3. Stability and dispersion

    Digital Repository Service at National Institute of Oceanography (India)

    Swamy, G.N.; Vijayakumar, C.V.

    Vertical profiles of currents of the coastal waters between Navapur and Umbharat were analysed. Dynamic stability as well as the diffusion capacity of the water columns were estimated from the vertical distribution of temperature, salinity...

  19. Water-rock interactions and the pH stability of groundwater from Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Ebinger, M.H.

    1992-01-01

    Titrations of acidic solutions in waters from the tuff and carbonate aquifers at Yucca Mountain were simulated using the geochemical codes PHREEQE and EQ3/6. The simulations tested pH stability of the waters in the presence of different minerals and in their absence. Two acidic solutions, 10 -4 HCl and 10 -4 M UO 2 (NO 3 ) 2 , were titrated in to the water. Little pH and/or compositional change resulted in the groundwater when the HCl solution was titrated, but significant pH and CO 2 fugacity changes were observed when UO 2 (NO 3 ) 2 was titrated. Water interactions with alkali feldspar, quartz or cristobalite, and Ca-smectite buffered the pH and compositional changes in the carbonate water and decreased the magnitude of pH and compositional changes when small volumes of UO 2 (NO 3 ) 2 added to the tuffaceous waters

  20. Changes in soil aggregate stability under different irrigation doses of waste water

    Science.gov (United States)

    Morugán, Alicia; García-Orenes, Fuensanta; Mataix-Solera, Jorge; Arcenegui, Victoria; Bárcenas, Gema

    2010-05-01

    Freshwater availability and soil degradation are two of the most important environmental problems in the Mediterranean area acerbated by incorrect agricultural use of irrigation in which organic matter is not correctly managed, the use of low quality water for irrigation, and the inefficiency of dose irrigation. For these reasons strategies for saving water and for the restoration of the mean properties of soil are necessary. The use of treated waste water for the irrigation of agricultural land could be a good solution to these problems, as it reduces the utilization of fresh water and could potentially improve key soil properties. In this work we have been studying, for more than three years, the effects on soil properties of different doses of irrigation with waste water. Here we show the results on aggregate stability. The study is located in an agricultural area at Biar (Alicante, SE of Spain), with a crop of grape (Vitis labrusca). Three types of waters are being used in the irrigation of the soil: fresh water (control) (TC), and treated waste water from secondary (T2) and tertiary treatment (T3). Three different doses of irrigation have been applied to fit the efficiency of the irrigation to the crop and soil type: D10 (10 L m-2 every week during 17 months), D50 (50 L m-2 every fifteen days during 14 moths) and D30 (30 L m-2 every week during 6 months up to present day). The results showed a clear decrease of aggregate stability during the period we used the second dose (D50) independent of the type of water used. That dose of irrigation and frequency produced strong wetting and drying cycles (WD) in the soil, and this is suspected to be the main factor responsible for the results. When we changed the dose of irrigation to D30, reducing the quantity per event and increasing the frequency, the soil aggregate stability started to improve. This dose avoids strong drying periods between irrigation events and the aggregate stability is confirmed to be slowly

  1. Water-quality and ground-water-level data, Bernalillo County, central New Mexico, 1995

    Science.gov (United States)

    Rankin, D.R.

    1996-01-01

    Water-quality and ground-water-level data were collected in two areas of eastern Bernalillo County in central New Mexico between March and July of 1995. Fifty-one wells, two springs, and the Ojo Grande Acequia in the east mountain area of Bernalillo County and nine wells in the northeast area of the city of Albuquerque were sampled. The water samples were analyzed for selected nutrient species; total organic carbon; major dissolved constituents; dissolved arsenic, boron, iron, and manganese; and methylene blue active substances. Analytical results were used to compute hardness, sodium adsorption ratio, and dissolved solids. Specific conductance, pH, temperature, and alkalinity were measured in the field at the time of sample collection. Ground- water-level and well-depth measurements were made at the time of sample collection when possible. Water-quality data, ground- water-level data, and well-depth data are presented in tabular form.

  2. Role of water balance in the long-term stability of hazardous waste site cover treatments

    International Nuclear Information System (INIS)

    Barnes, F.J.; Rodgers, J.C.; Trujillo, G.

    1986-01-01

    After the 30-year post-closure maintenance period at hazardous waste landfills, long-term stability must be assured without continued intervention. Understanding water balance in the established vegetative cover system is central to predicting such stability. A Los Alamos National Laboratory research project has established a series of experimental cover treatment plots on a closed waste disposal site which will permit the determination of the effects of such critical parameters as soil cover design, leaf area index, and rooting characteristics on water balance under varied conditions. Data from these experiments are being analyzed by water balance modeling and other means. The results show consistent differences in soil moisture storage between soil profiles and between vegetation cover treatments

  3. Hydromagnetic Stability of Metallic Nanofluids (Cu-Water and Ag-Water Using Darcy-Brinkman Model

    Directory of Open Access Journals (Sweden)

    J. Ahuja

    2016-01-01

    Full Text Available Thermal convection of a nanofluid layer in the presence of imposed vertical magnetic field saturated by a porous medium is investigated for both-free, rigid-free, and both-rigid boundaries using Darcy-Brinkman model. The effects of Brownian motion and thermophoretic forces due to the presence of nanoparticles and Lorentz’s force term due to the presence of magnetic field have been considered in the momentum equations along with Maxwell’s equations. Keeping in mind applications of flow through porous medium in geophysics, especially in the study of Earth’s core, and the presence of nanoparticles therein, the hydromagnetic stability of a nanofluid layer in porous medium is considered in the present formulation. An analytical investigation is made by applying normal mode technique and Galerkin type weighted residuals method and the stability of Cu-water and Ag-water nanofluids is compared. Mode of heat transfer is through stationary convection without the occurrence of oscillatory motions. Stability of the system gets improved appreciably by raising the Chandrasekhar number as well as Darcy number whereas increase in porosity hastens the onset of instability. Further, stability of the system gets enhanced as we proceed from both-free boundaries to rigid-free and to both-rigid boundaries.

  4. Maps of the topography of water surface levels in the Danube Delta, between the main branches

    Directory of Open Access Journals (Sweden)

    BONDAR Constantin

    2016-12-01

    Full Text Available Within the project “Hydrological Monitoring of Wetland Areas Using SAR Techniques (Hydro-SAR”, concluded by the TERRASIGNA (Romania with the European Space Agency (ESA, the task of GeoEcoMar was to track and check the correlation of data provided by InSAR techniques with ground observations and measurements in the Danube Delta. Activities in the field and laboratory enabled elaboration of maps of vector fields for the water flow directions on the Danube Delta territory, based on the relief of the water surface levels at 450, 400, 350, 300, 250, 200, 150, 100, 50 and 0 cm, measured at Tulcea hydrologic station. In order to elaborate the maps of water surface levels, the altimetric stability of hydrometric gauges from the Danube Delta territorry was checked by establishing the Earth crust subsidence in each gauge location. Interpretation of recorded data shows a relative low subsidence rate for the location of the hydrometric gauge in Tulcea (observations recorded for the period 1858-2013 selected as hydrometric reference point, with the origin of the zero of the gauge situated at 0.57 m altitude relative to the Black Sea – Sulina reference system. The paper presents isoline maps of the water surface levels on the surface of the Danube Delta between the main distributaries (Chilia – Sulina – Sf. Gheorghe, for the above mentioned water surface levels.

  5. Comparative water quality assessment between a young and a stabilized hydroelectric reservoir in Aliakmon River, Greece.

    Science.gov (United States)

    Samiotis, Georgios; Trikoilidou, Eleni; Tsikritzis, Lazaros; Amanatidou, Elisavet

    2018-03-20

    In this work, a comparative study on the water quality characteristics of two in-line water reservoirs (artificial lakes) in Aliakmon River (Western Macedonia, Greece) is performed. Polyfytos Reservoir and Ilarion Reservoir were created in 1975 and 2012 respectively, in order to serve the homonymous hydroelectric stations. In young artificial lakes, severe deterioration of water quality may occur; thus, the monitoring and assessment of their water quality characteristics and their statistical interpretation are of great importance. In order to evaluate any temporal or spatial variations and to characterize water quality of these two in-line water reservoirs, water quality data from measurements conducted from 2012 to 2015 were statistically processed and interpreted by using a modified National Sanitation Foundation water quality index (WQI). The water physicochemical characteristics of the two reservoirs were found to be generally within the legislation limits, with relatively small temporal and spatial variations. Although Polyfytos Reservoir showed no significant deviations of its water quality, Ilarion Reservoir exhibited deviations in total Kjeldahl nitrogen, nitrite nitrogen, total suspended solids, and turbidity due to the inundated vegetation decomposition. The conducted measurements and the use of the modified NSFWQI revealed that during the inundation period of Ilarion Reservoir, its water quality was "moderate" and that the deviations were softened through time, leading to "good" water quality during its maturation period. Three years since the creation of Ilarion Reservoir, water quality does not match that of Aliakmon River (feeding water) or that of the stabilized reservoir (Polyfytos Reservoir), whose quality is characterized as "high." The use of a WQI, such as the proposed modified NSFWQI, for evaluating water quality of each sampling site and of an entire water system proved to be a rapid and relatively accurate assessment tool.

  6. Influence of osmolytes on protein and water structure: a step to understanding the mechanism of protein stabilization.

    Science.gov (United States)

    Bruździak, Piotr; Panuszko, Aneta; Stangret, Janusz

    2013-10-03

    Results concerning the thermostability of hen egg white lysozyme in aqueous solutions with stabilizing osmolytes, trimethylamine-N-oxide (TMAO), glycine (Gly), and its N-methyl derivatives, N-methylglycine (NMG), N,N-dimethylglycine (DMG), and N,N,N-trimethylglycine (betaine, TMG), have been presented. The combination of spectroscopic (IR) and calorimetric (DSC) data allowed us to establish a link between osmolytes' influence on water structure and their ability to thermally stabilize protein molecule. Structural and energetic characteristics of stabilizing osmolytes' and lysozyme's hydration water appear to be very similar. The osmolytes increase lysozyme stabilization in the order bulk water molecules affected by osmolytes in their surrounding. Obtained results verified the hypothesis concerning the role of water molecules in protein stabilization, explained the osmophobic effect, and finally helped to bring us nearer to the exact mechanism of protein stabilization by osmolytes.

  7. Tradeoffs between water requirements and yield stability in annual vs. perennial crops

    Science.gov (United States)

    Vico, Giulia; Brunsell, Nathaniel A.

    2018-02-01

    Population growth and changes in climate and diets will likely further increase the pressure on agriculture and water resources globally. Currently, staple crops are obtained from annuals plants. A shift towards perennial crops may enhance many ecosystem services, but at the cost of higher water requirements and lower yields. It is still unclear when the advantages of perennial crops overcome their disadvantages and perennial crops are thus a sustainable solution. Here we combine a probabilistic description of the soil water balance and crop development with an extensive dataset of traits of congeneric annuals and perennials to identify the conditions for which perennial crops are more viable than annual ones with reference to yield, yield stability, and effective use of water. We show that the larger and more developed roots of perennial crops allow a better exploitation of soil water resources and a reduction of yield variability with respect to annual species, but their yields remain lower when considering grain crops. Furthermore, perennial crops have higher and more variable irrigation requirements and lower water productivity. These results are important to understand the potential consequences for yield, its stability, and water resource use of a shift from annual to perennial crops and, more generally, if perennial crops may be more resilient than annual crops in the face of climatic fluctuations.

  8. Water stability of soil aggregates in different systems of Chernozem tillage

    Directory of Open Access Journals (Sweden)

    Jaroslava Bartlová

    2011-01-01

    Full Text Available Effects of various agrotechnical measures on macrostructural changes in the ploughing layer and subsoil were studied within the period of 2008–2010. Soil macrostructure was evaluated on the base of water stability of soil aggregates. Altogether three variants of soil tillage were established, viz. ploughing to the depth of 0.22 m (Variant 1, deep soil loosening to the depth of 0.35–0.40 m (Variant 2, and shallow tillage to the depth of 0.15 m (Variant 3. Experiments were established on a field with Modal Chernozem in the locality Hrušovany nad Jevišovkou (maize-growing region, altitude of 210 m, average annual sum of precipitation 461 mm. In the first experimental year, winter rape was the cultivated crop and it was followed by winter wheat, maize and spring wheat in subsequent years. The aim of this study was to evaluate effects of different methods of tillage on water stability of soil aggregates and on yields of individual crops. An overall analysis of results revealed a positive effect of cultivation without ploughing on water stability of soil aggregates. In the variant with ploughing was found out a statistically significant decrease of this stability. At the same time it was also found out that both minimum tillage and deep soil loosening showed a positive effect on yields of crops under study (above all of maize and winter wheat.

  9. Rapid and controlled transformation of nitrate in water and brine by stabilized iron nanoparticles

    International Nuclear Information System (INIS)

    Xiong Zhong; Zhao Dongye; Pan Gang

    2009-01-01

    Highly reactive zero-valent iron (ZVI) nanoparticles stabilized with carboxymethyl cellulose (CMC) were tested for reduction of nitrate in fresh water and brine. Batch kinetic tests showed that the pseudo first-order rate constant (k obs ) with the stabilized nanoparticles was five times greater than that for non-stabilized counterparts. The stabilizer not only increased the specific surface area of the nanoparticles, but also increased the reactive particle surface. The allocation between the two reduction products, NH 4 + and N 2 , can be manipulated by varying the ZVI-to-nitrate molar ratio and/or applying a Cu-Pd bimetallic catalyst. Greater CMC-to-ZVI ratios lead to faster nitrate reduction. Application of a 0.05 M HEPES buffer increased the k obs value by 15 times compared to that without pH control. Although the presence of 6% NaCl decreased k obs by 30%, 100% nitrate was transformed within 2 h in the saline water. The technology provides a powerful alternative for treating water with concentrated nitrate such as ion exchange brine.

  10. Water-Table Levels and Gradients, Nevada, 1947-2004

    Science.gov (United States)

    Lopes, Thomas J.; Buto, Susan G.; Smith, J. LaRue; Welborn, Toby L.

    2006-01-01

    In 1999, the U.S. Environmental Protection Agency began a program to protect the quality of ground water in areas other than ground-water protection areas. These other sensitive ground water areas (OSGWA) are areas that are not currently, but could eventually be, used as a source of drinking water. The OSGWA program specifically addresses existing wells that are used for underground injection of motor-vehicle waste. To help determine whether a well is in an OSGWA, the Nevada Division of Environmental Protection needs statewide information on depth to water and the water table, which partly control the susceptibility of ground water to contamination and contaminant transport. This report describes a study that used available maps and data to create statewide maps of water-table and depth-to-water contours and surfaces, assessed temporal changes in water-table levels, and characterized water-table gradients in selected areas of Nevada. A literature search of published water-table and depth-to-water contours produced maps of varying detail and scope in 104 reports published from 1948 to 2004. Where multiple maps covered the same area, criteria were used to select the most recent, detailed maps that covered the largest area and had plotted control points. These selection criteria resulted in water-table and depth-to-water contours that are based on data collected from 1947 to 2004 being selected from 39 reports. If not already available digitally, contours and control points were digitized from selected maps, entered into a geographic information system, and combined to make a statewide map of water-table contours. Water-table surfaces were made by using inverse distance weighting to estimate the water table between contours and then gridding the estimates. Depth-to-water surfaces were made by subtracting the water-table altitude from the land-surface altitude. Water-table and depth-to-water surfaces were made for only 21 percent of Nevada because of a lack of

  11. Stability of Anthocyanins from Rubus glaucus and Solanum betaceum as affected by Temperature and Water Activity

    Directory of Open Access Journals (Sweden)

    Clara Marcela Olaya

    2009-09-01

    Full Text Available The stability of sprayed-dried microencapsulated anthocyanins from Andes berry (Rubus glaucus and Tamarillo (Solanum betaceum, as affected by storage time, water activity (Aw and temperature was compared. The fruits were osmotically dehydrated with ethanol and the anthocyanin extract was microencapsulated with maltodextrin DE 20 by spray drying. Half life of the anthocyanins; changes in color, total phenolics, and antioxidant activity of the powders, were analyzed during storage at two different temperatures (25 °C and 40 °C and two Aw levels (0.20 and 0.35. A decrease in monomeric anthocyanin was observed in both samples. The half life of the Andes berry pigments ranged between 11 and 32 days while the half life of the tamarillo pigments ranged between 9 and 21 days. A darkening effect occurred in both samples as a result of storage time.  The antioxidant activity decreased while the phenolic content increased with time. Antioxidant activity of Andes berry samples was highly correlated with anthocyanin content and total phenolic content while the antioxidant activity of tamarillo samples was highly correlated with total phenolic content. These results would be useful in developing applications for spray-dried anthocyanin as powdered food-grade colorants.

  12. Phenolic residues in spruce galactoglucomannans improve stabilization of oil-in-water emulsions.

    Science.gov (United States)

    Lehtonen, M; Merinen, M; Kilpeläinen, P O; Xu, C; Willför, S M; Mikkonen, K S

    2018-02-15

    Amphiphilic character of surfactants drives them at the interface of dispersed systems, such as emulsions. Hemicellulose-rich wood extracts contain assemblies (lignin-carbohydrate complexes, LCC) with natural amphiphilicity, which is expected to depend on their chemical composition resulting from the isolation method. Lignin-derived phenolic residues associated with hemicelluloses are hypothesized to contribute to emulsions' interfacial properties and stability. We investigated the role of phenolic residues in spruce hemicellulose extracts in the stabilization of oil-in-water emulsions by physical and chemical approach. Distribution and changes occurring in the phenolic residues at the droplet interface and in the continuous phase were studied during an accelerated storage test. Meanwhile, the physical stability and lipid oxidation in emulsions were monitored. Naturally associated lignin residues in GGM act as vehicles for anchoring these hemicelluloses into the oil droplet interface and further enable superior stabilization of emulsions. By adjusting the isolation method of GGM regarding their phenolic profile, their functionalities, especially interfacial behavior, can be altered. Retaining the native interactions of GGM and phenolic residues is suggested for efficient physical stabilization and extended protection against lipid oxidation. The results can be widely applied as guidelines in tailoring natural or synthetic amphiphilic compounds for interfacial stabilization. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Suspensions Plasma Spraying of Ceramics with Hybrid Water-Stabilized Plasma Technology

    Czech Academy of Sciences Publication Activity Database

    Mušálek, Radek; Medřický, Jan; Tesař, T.; Kotlan, Jiří; Pala, Zdeněk; Lukáč, František; Chráska, Tomáš; Curry, N.

    2017-01-01

    Roč. 26, 1-2 (2017), s. 37-46 ISSN 1059-9630. [ISTC 2016: International Thermal Spray Conference. Shanghai, 10.05.2016-12.05.2016] R&D Projects: GA ČR GA15-12145S Institutional support: RVO:61389021 Keywords : alumina * ceramics * dense * hybrid plasma torch * suspension plasma spraying * water-stabilized plasma * yttria-stabilized zirconia (YSZ) Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 1.488, year: 2016 http://link.springer.com/article/10.1007/s11666-016-0493-6

  14. Role of specific cations and water entropy on the stability of branched DNA motif structures.

    Science.gov (United States)

    Pascal, Tod A; Goddard, William A; Maiti, Prabal K; Vaidehi, Nagarajan

    2012-10-11

    DNA three-way junctions (TWJs) are important intermediates in various cellular processes and are the simplest of a family of branched nucleic acids being considered as scaffolds for biomolecular nanotechnology. Branched nucleic acids are stabilized by divalent cations such as Mg(2+), presumably due to condensation and neutralization of the negatively charged DNA backbone. However, electrostatic screening effects point to more complex solvation dynamics and a large role of interfacial waters in thermodynamic stability. Here, we report extensive computer simulations in explicit water and salt on a model TWJ and use free energy calculations to quantify the role of ionic character and strength on stability. We find that enthalpic stabilization of the first and second hydration shells by Mg(2+) accounts for 1/3 and all of the free energy gain in 50% and pure MgCl(2) solutions, respectively. The more distorted DNA molecule is actually destabilized in pure MgCl(2) compared to pure NaCl. Notably, the first shell, interfacial waters have very low translational and rotational entropy (i.e., mobility) compared to the bulk, an entropic loss that is overcompensated by increased enthalpy from additional electrostatic interactions with Mg(2+). In contrast, the second hydration shell has anomalously high entropy as it is trapped between an immobile and bulklike layer. The nonmonotonic entropic signature and long-range perturbations of the hydration shells to Mg(2+) may have implications in the molecular recognition of these motifs. For example, we find that low salt stabilizes the parallel configuration of the three-way junction, whereas at normal salt we find antiparallel configurations deduced from the NMR. We use the 2PT analysis to follow the thermodynamics of this transition and find that the free energy barrier is dominated by entropic effects that result from the decreased surface area of the antiparallel form which has a smaller number of low entropy waters in the first

  15. Lake St. Clair: Storm Wave and Water Level Modeling

    Science.gov (United States)

    2013-06-01

    moving synoptic , and meso-scale meteorological events as they crossed Lake Michigan. It was observed at the onset of this study that Lake St...significant wave height, and a negative bias in the wave period estimates. All of these results present a different picture than the previous tests. As in...simulation forcing parameters:  Input the ADCIRC mesh (fort.14) and the water level adjustment to the synoptic lake level (fort.13) for a specific storm

  16. Impact of Environmental Stresses on Orange Oil-in-Water Emulsions Stabilized by Sucrose Monopalmitate and Lysolecithin.

    Science.gov (United States)

    McClements, David Julian; Decker, Eric Andrew; Choi, Seung Jun

    2014-04-09

    The food and beverage industry is trying to replace synthetic functional ingredients with more "label-friendly" ingredients in many commercial products. This study therefore examined the influence of environmental stresses on the stability of emulsions stabilized by a combination of lysolecithin and sucrose monopalmitate (SMP). Orange oil-in-water emulsions (5% (w/w) oil) stabilized by SMP (1%) and lysolecithin (0-0.5%) were prepared using high-pressure homogenization (pH 3). In the absence of lysolecithin, all emulsions were highly unstable to droplet aggregation, which was attributed to low droplet charge (weak electrostatic repulsion) and small SMP headgroup size (weak steric repulsion). Incorporation of 0.1-0.5% lysolecithin into the emulsions greatly improved their stability to droplet aggregation, which was mainly attributed to the increase in negative charge on the droplets (strong electrostatic repulsion). The addition of high levels of salt (NaCl) to the emulsions promoted droplet aggregation and creaming. Emulsions containing 0.5% lysolecithin were stable to heating (30-90 °C) in the absence of salt, but exhibited droplet aggregation and creaming when held at high (>50 °C) temperatures in the presence of 300 mM salt. This study has implications for the development of emulsion-based delivery systems for use in food and beverage products.

  17. The phenotypic equilibrium of cancer cells: From average-level stability to path-wise convergence.

    Science.gov (United States)

    Niu, Yuanling; Wang, Yue; Zhou, Da

    2015-12-07

    The phenotypic equilibrium, i.e. heterogeneous population of cancer cells tending to a fixed equilibrium of phenotypic proportions, has received much attention in cancer biology very recently. In the previous literature, some theoretical models were used to predict the experimental phenomena of the phenotypic equilibrium, which were often explained by different concepts of stabilities of the models. Here we present a stochastic multi-phenotype branching model by integrating conventional cellular hierarchy with phenotypic plasticity mechanisms of cancer cells. Based on our model, it is shown that: (i) our model can serve as a framework to unify the previous models for the phenotypic equilibrium, and then harmonizes the different kinds of average-level stabilities proposed in these models; and (ii) path-wise convergence of our model provides a deeper understanding to the phenotypic equilibrium from stochastic point of view. That is, the emergence of the phenotypic equilibrium is rooted in the stochastic nature of (almost) every sample path, the average-level stability just follows from it by averaging stochastic samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Axial offset as measure of stability of light water nuclear reactor during capacity maneuvering

    Directory of Open Access Journals (Sweden)

    Mark V. Nikolsky

    2015-03-01

    Full Text Available High reliability and security of power unit are required during operation of power unit while maneuvering. They depend on the stability of reactor when transition from one power level to another. The axial offset is a quantitative measure of the reactor stability. It is shown that change of the active core inlet coolant temperature yields an uncontrollable disturbance affecting the axial offset and therefore the reactor stability. To insure the reactor stability the compromise-combined power control method is proposed. Analysis of the influence of temperature of coolant at the magnitude of the axial offset for different regulatory programs is carried out. The change in the depth of immersion of regulators in the active zone for different regulatory programs when the reactor plant daily capacity maneuver is studied.

  19. Water level oscillations in Monterey Bay and Harbor

    Directory of Open Access Journals (Sweden)

    J. Park

    2015-06-01

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

  20. Detection of a reservoir water level using shape similarity metrics

    Science.gov (United States)

    Pipitone, Claudia; Maltese, Antonino; Dardanelli, Gino; Capodici, Fulvio; Lo Brutto, Mauro; La Loggia, Goffredo

    2017-10-01

    The matching between reservoirs' water edge and digital elevation model's (DEM) contour lines allowed determining the water level at the acquisition date of satellite images. A preliminary study was conducted on the Castello dam (Magazzolo Lake), between Alessandria della Rocca and Bivona (Agrigento, south-Italy). The accuracy assessment of the technique was than evaluated from the comparison between classified and reference objects using similarity metrics about the shape, theme, edge and position, through the plugin STEP of open source software GIS. Moreover, an independent GIS technique was implemented to evaluate the water level, based on a distances' array between existing contour lines and nodes extracted from vectorised classification images. Results have shown the potentiality of the techniques when applied on an ideal case; advantages and disadvantages when the images are characterized by clear sky, and limits when images are acquired during not ideal atmospheric conditions.

  1. CLINICAL EVALUATION OF THE STABILITY OF IMPLANTS PLACED AT DIFFERENT SUPRACRESTAL LEVELS

    Directory of Open Access Journals (Sweden)

    B. Alper GÜLTEKIN

    2016-10-01

    Full Text Available Purpose: The aim of this study was to evaluate the stability during healing and before loading of implants placed at two different supracrestal levels according to their collar texture. Materials and Methods: This retrospective study included patients who received posterior implants with the same macro design. Implants with a machined collar were placed 0.3 mm above the crestal bone (M group, while those with a laser-microtextured collar were placed 1 mm above the crestal bone (L group. All implants healed in a single stage with healing abutments. Implant stability quotient (ISQ values were determined using resonance frequency analysis immediately after implant placement during surgery and after 1, 4, 8, and 12 weeks after surgery. Other evaluated factors for stability included the implant diameter and length and the site of placement (maxilla or mandible. Results: In total, 103 implants (47 L, 56 M were evaluated. The median ISQ values at baseline and 1 week after placement were significantly higher for the M group than for the L group (p=0.006 and p=0.031, respectively. There were no differences at the subsequent observation points. The ISQ value was higher for wide-diameter than regular diameter (p=0.001 and mandibular implants than maxillary implants (p=0.001 at 0-8. weeks; p=0.012 at 12 weeks at all observation points. When diameter data were neglected, the implant length did not influence the ISQ value at all observation points. Conclusion: Our results suggest that submerging implant more inside bone may only influence primary stability. Moreover, the implant diameter and site of placement influence primary and secondary stability before loading, whereas the implant length does not when its diameter is not accounted for.

  2. Hammerhead ribozyme activity and oligonucleotide duplex stability in mixed solutions of water and organic compounds

    Directory of Open Access Journals (Sweden)

    Shu-ichi Nakano

    2014-01-01

    Full Text Available Nucleic acids are useful for biomedical targeting and sensing applications in which the molecular environment is different from that of a dilute aqueous solution. In this study, the influence of various types of mixed solutions of water and water-soluble organic compounds on RNA was investigated by measuring the catalytic activity of the hammerhead ribozyme and the thermodynamic stability of an oligonucleotide duplex. The compounds with a net neutral charge, such as poly(ethylene glycol, small primary alcohols, amide compounds, and aprotic solvent molecules, added at high concentrations changed the ribozyme-catalyzed RNA cleavage rate, with the magnitude of the effect dependent on the NaCl concentration. These compounds also changed the thermodynamic stability of RNA base pairs of an oligonucleotide duplex and its dependence on the NaCl concentration. Specific interactions with RNA molecules and reduced water activity could account for the inhibiting effects on the ribozyme catalysis and destabilizing effects on the duplex stability. The salt concentration dependence data correlated with the dielectric constant, but not with water activity, viscosity, and the size of organic compounds. This observation suggests the significance of the dielectric constant effects on the RNA reactions under molecular crowding conditions created by organic compounds.

  3. Levels of trace elements in MWSS drinking water

    International Nuclear Information System (INIS)

    Andal, T.T.

    1998-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Dennis Wichelns

    2014-03-01

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

  5. radio frequency based radio frequency based water level monitor

    African Journals Online (AJOL)

    eobe

    It is completely automated with the help of a PIC 16F877A micro controller which receives signals from the transmitter, transmitter, interprets and effectively communicates the stat interprets and .... to electrolysis, but in this work pure stainless probes are used and placed at different levels of the tank such that whenever water ...

  6. Determination of the Level of Contamination of Underground Water ...

    African Journals Online (AJOL)

    Misrak

    Determination of the Level of Contamination of. Underground Water (hand- dug well) by Organic Waste: A case Study of Ado-Ekiti, Nigeria. O.S. Omotoyinbo *. Abstract. The recent increase in urbanization has lead to increase in city population, spatial size, and generation of waste. This is a common phenomenon in Nigeria ...

  7. Comparison Between Water Level and Precipitation in Rio Negro Basin

    Science.gov (United States)

    Figliuolo, G. C.; Santos Da Silva, J.; Calmant, S.; Seyler, F.; Correia, F.; Oliveira, R. J.

    2013-12-01

    The Amazon Basin holds a lot of difficulties for providing data that enable regional researching works, because of its large extension and for having areas, whose access is very difficult. Remote sensing data presents an excellent way for monitoring the Amazon Basin and collecting data for researches. This current study aims matching radar altimetry data from the JASON-2, with the rainfall data from the TRMM satellite in order to analyze the relation between the water level and the precipitation in two different points along the Rio Negro Basin. After data analysis, it was possible noting a difference on the responding process for both regions. Whilst at the NEGRO_089_03 station (located in the city of São Gabriel da Cachoeira) the graphic of precipitation and water level were very similar, in NEGRO_063 station (located in the city of Manaus) the graphic showed a two month discrepancy due to the difference of the river's bottom size in both regions, at NEGRO_089_03's area for having a smaller river and the water level rises faster, whereas in NEGRO_063 the water level takes about two months to respond to precipitation.

  8. Water quality characteristics and pollution levels of heavy metals in ...

    African Journals Online (AJOL)

    The main aim of this study was to assess the level of water quality of Lake Haiq, Ethiopia with respect to selected physical parameters and heavy metals. Parameters such as temperature, pH, turbidity, electrical conductivity and total dissolved solids were measured in situ. While total alkalinity, chloride, ammonia, nitrate and ...

  9. Radio Frequency Based Water Level Monitor and Controller for ...

    African Journals Online (AJOL)

    This paper elucidates a radio frequency (RF) based transmission and reception system used to remotely monitor and control the water Level of an overhead tank placed up to 100 meters away from the pump and controller. It uses two Radio Frequency transceivers along with a controller each installed at the overhead tank ...

  10. Internalising a Crisis? Household Level Response to Water Scarcity ...

    African Journals Online (AJOL)

    In the last quarter of 2008, Zimbabwe grabbed international news headlines because of a cholera outbreak that was said to be the worst in Africa in 15 years. The outbreak was attributed to inadequate and poor quality of domestic water at household level. This paper examines how households from different socioeconomic ...

  11. Effect of electrolyzed reduced water on malondialdehyde levels and ...

    African Journals Online (AJOL)

    Purpose: To evaluate the effects of electrolyzed reduced water (ERW) on malondialdehyde (MDA) levels and neutrophil cells in Wistar rats suffering from aggressive periodontitis. Methods: Wistar rats (Rattus norvegicus) were infected with A. actinomycetemcomitans before being divided into a control group and a treatment ...

  12. Removal of Stabilized Silver Nanoparticles from Ohio River Water by Potable Water Treatment Processes

    Science.gov (United States)

    Due to their extensive use, silver nanoparticles (Ag NPs) are likely to occur in drinking water sources. Once released into the environment they are considered an emerging contaminant in water and wastewater. The main objective of this research is to investigate the removal of di...

  13. Plant wide chemical water stability modelling with PHREEQC for drinking water treatment

    NARCIS (Netherlands)

    Van der Helm, A.W.C.; Kramer, O.J.I.; Hooft, J.F.M.; De Moel, P.J.

    2015-01-01

    In practice, drinking water technologists use simplified calculation methods for aquatic chemistry calculations. Recently, the database stimela.dat is developed especially for aquatic chemistry for drinking water treatment processes. The database is used in PHREEQC, the standard in geohydrology for

  14. Stability Analysis of Numerical Methods for a 1.5-Layer Shallow-Water Ocean Model

    Directory of Open Access Journals (Sweden)

    Guang-an Zou

    2013-01-01

    Full Text Available A 1.5-layer reduced-gravity shallow-water ocean model in spherical coordinates is described and discretized in a staggered grid (standard Arakawa C-grid with the forward-time central-space (FTCS method and the Leap-frog finite difference scheme. The discrete Fourier analysis method combined with the Gershgorin circle theorem is used to study the stability of these two finite difference numerical models. A series of necessary conditions of selection criteria for the time-space step sizes and model parameters are obtained. It is showed that these stability conditions are more accurate than the Courant-Friedrichs-Lewy (CFL condition and other two criterions (Blumberg and Mellor, 1987; Casulli, 1990, 1992. Numerical experiments are proposed to test our stability results, and numerical model that is designed is also used to simulate the ocean current.

  15. Design of various fixed-geometry water-lubricated hydrodynamic journal bearings for maximum stability

    Science.gov (United States)

    Schuller, F. T.

    1973-01-01

    This publication is the result of over 260 fractional-frequency-whirl stability tests on a variety of fixed-geometry journal bearings. It is intended principally as a guide in the selection and design of antiwhirl bearings that must operate at high speeds and low loads in low-viscosity fluids such as water or liquid metals. However, the various fixed-geometry configurations can be employed as well in applications where other lubricants, such as oil, are used and fractional-frequency whirl is a problem. The important parameters that effect stability are discussed for each bearing type, and design curves to facilitate the design of optimum-geometry bearings are included. A comparison of the stability of the different bearing configurations tested is also given.

  16. Sunlight mediated inactivation mechanisms of Enterococcus faecalis and Escherichia coli in clear water versus waste stabilization pond water.

    Science.gov (United States)

    Kadir, Khalid; Nelson, Kara L

    2014-03-01

    Escherichia coli and enterococci have been previously reported to differ in the mechanisms and conditions that affect their sunlight-mediated inactivation in waste stabilization ponds. This study was undertaken to further characterize these mechanisms, using simulated sunlight and single strains of laboratory-grown E. coli and Enterococcus faecalis, with a focus on characterizing the contribution of exogenous reactive oxygen species to the inactivation process. We found that direct damage by UVB light (280-320 nm) was not a significant inactivation mechanism for either organism. E. coli inactivation was strongly dependent on dissolved oxygen concentrations and the presence of UVB wavelengths but E. coli were not susceptible to inactivation by exogenous sensitizers present in waste stabilization pond water. In contrast, E. faecalis inactivation in pond water occurred primarily through exogenous mechanisms, with strong evidence that singlet oxygen is an important transient reactive species. The exogenous mechanism could utilize wavelengths into the visible spectrum and sensitizers were mainly colloidal, distributed between 0.2 and ∼1 μm in size. Singlet oxygen is likely an important endogenous species in both E. faecalis and E. coli inactivation due to sunlight. Although the two organisms had similar inactivation rates in buffered, clear water, the inactivation rate of E. faecalis was 7 times greater than that of E. coli in air-saturated pond water at circumneutral pH due to its susceptibility to exogenous sensitizers and longer wavelengths. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Water level observations from Unmanned Aerial Vehicles for improving estimates of surface water-groundwater interaction

    DEFF Research Database (Denmark)

    Bandini, Filippo; Butts, Michael; Vammen Jacobsen, Torsten

    2017-01-01

    . However, traditional river gauging stations are normally spaced too far apart to capture spatial patterns in the water surface, while spaceborne observations have limited spatial and temporal resolution. UAVs (Unmanned Aerial Vehicles) can retrieve river water level measurements, providing: i) high...

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

    NARCIS (Netherlands)

    Cai, H.; Savenije, H.H.G.; Jiang, C.

    2014-01-01

    As the tidal wave propagates into an estuary, the tidally averaged water level tends to rise in landward direction due to the density difference between saline and fresh water and the asymmetry of the friction. The effect of friction on the residual slope is even more remarkable when accounting for

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

    Science.gov (United States)

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

    2011-02-01

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

  20. Ultrastable offset-locked frequency-stabilized heterodyne laser source with water cooling.

    Science.gov (United States)

    Yang, Hongxing; Yang, Ruitao; Hu, Pengcheng; Tan, Jiubin

    2017-11-20

    An ultrastable frequency-stabilized He-Ne laser with a water-cooling structure has been developed for a high-speed and high-accuracy heterodyne interferometer. To achieve high frequency stability and reproducibility, a two-mode He-Ne laser was offset locked to an iodine-stabilized laser. An improved synchronous multi-cycle offset frequency-measurement method with a gate time of an integer multiple of the modulation period was employed to remove the frequency-modulation effect on the offset-frequency counter. A water-cooling structure based on the double-helix structure was established to provide a stable and low-temperature working environment. This structure can remarkably reduce the frequency instability arising from the environmental temperature variation and the thermal pollution released from the laser to the environment. The experimental results indicate that the frequency stability according to the Allen variance is better than 2.3×10 -11 (τ=10  s) and the frequency reproducibility is better than 4.5×10 -10 .

  1. Water-in-oil Pickering emulsions stabilized by stearoylated microcrystalline cellulose.

    Science.gov (United States)

    Pang, Bo; Liu, Huan; Liu, Peiwen; Peng, Xinwen; Zhang, Kai

    2018-03-01

    Hydrophobic particles with static water contact angles larger than 90° are more like to stabilize W/O Pickering emulsions. In particular, high internal phase Pickering emulsions (HIPEs) are of great interest for diverse applications. However, W/O HIPEs have rarely been realized using sustainable biopolymers. Herein, we used stearoylated microcrystalline cellulose (SMCC) to stabilize W/O Pickering emulsions and especially, W/O HIPEs. Moreover, these W/O HIPEs can be further used as platforms for the preparation of porous materials, such as porous foams. Stearoylated microcrystalline cellulose (SMCC) was prepared by modifying MCC with stearoyl chloride under heterogeneous conditions. Using SMCC as emulsifiers, W/O medium and high internal phase Pickering emulsions (MIPEs and HIPEs) with various organic solvents as continuous phases were prepared using one-step and two-step methods, respectively. Polystyrene (PS) foams were prepared after polymerization of oil phase using HIPEs as templates and their oil/water separation capacity were studied. SMCC could efficiently stabilize W/O Pickering emulsions and HIPEs could only be prepared via the two-step method. The internal phase volume fraction of the SMCC-stabilized HIPEs reached as high as 89%. Diverse internal phase volume fractions led to distinct inner structures of foams with closed or open cells. These macroporous polystyrene (PS) foams demonstrated great potential for the effective absorption of organic solvents from underwater. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Phenomenological nuclear level densities using the KTUY05 nuclear mass formula for applications off-stability

    International Nuclear Information System (INIS)

    Kawano, Toshihiko; Chiba, Satoshi; Koura, Hiroyuki

    2006-01-01

    A new parametrization for the phenomenological nuclear level density taking account of the shell and pairing energies of the recent nuclear mass formula of Koura, Tachibana, Uno, and Yamada (KTUY05) is proposed. Such a level density formula is often required to calculate nuclear reaction cross sections for nuclei off-stability, especially for fission systems and astrophysical applications. With the phenomenological level density formula of Gilbert-Cameron with the energy dependent level density parameter of Ignatyuk, a smooth dependence of the asymptotic level density parameter a * on the mass number is obtained. At low energies, systematics for the constant temperature model are also derived by connecting the Fermi gas level density and the discrete level information available for more than 1,000 nuclei. Some comparisons with the discrete level data and the microscopic model are made to validate our approach, and it is concluded that the parametrization obtained can be used for nuclear reaction calculations on stable or unstable nuclei within a reasonable uncertainty. (author)

  3. Standard Test Method for Preparing Aircraft Cleaning Compounds, Liquid Type, Water Base, for Storage Stability Testing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers the determination of the stability in storage, of liquid, water-base chemical cleaning compounds, used to clean the exterior surfaces of aircraft. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  4. Stability of Anthocyanins from Rubus glaucus and Solanum betaceum as affected by Temperature and Water Activity

    OpenAIRE

    Clara Marcela Olaya; Maria Paola Castaño; Gloria Astrid Garzon Monroy

    2009-01-01

    The stability of sprayed-dried microencapsulated anthocyanins from Andes berry (Rubus glaucus) and Tamarillo (Solanum betaceum), as affected by storage time, water activity (Aw) and temperature was compared. The fruits were osmotically dehydrated with ethanol and the anthocyanin extract was microencapsulated with maltodextrin DE 20 by spray drying. Half life of the anthocyanins; changes in color, total phenolics, and antioxidant activity of the powders, were analyzed during storage at two dif...

  5. Stability of Anthocyanins from Rubus glaucus and Solanum betaceum as affected by Temperature and Water Activity

    OpenAIRE

    Garzon Monroy Gloria Astrid; Castaño Maria Paola; Olaya Clara Marcela

    2009-01-01

    The stability of sprayed-dried microencapsulated anthocyanins from Andes berry (Rubus glaucus) and Tamarillo (Solanum betaceum), as affected by storage time, water activity (Aw) and temperature was compared. The fruits were osmotically dehydrated with ethanol and the anthocyanin extract was microencapsulated with maltodextrin DE 20 by spray drying. Half life o...

  6. Color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for non metal clasp denture

    OpenAIRE

    Jang, Dae-Eun; Lee, Ji-Young; Jang, Hyun-Seon; Lee, Jang-Jae; Son, Mee-Kyoung

    2015-01-01

    PURPOSE The aim of this study was to compare the color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for the non-metal clasp dentures to those of thermoplastic polyamide and conventional heat-polymerized denture base resins. MATERIALS AND METHODS Three types of denture base resin, which are conventional heat-polymerized acrylic resin (Paladent 20), thermoplastic polyamide resin (Bio Tone), thermoplastic acrylic resin (Acrytone) were used as materials for this study...

  7. Characterizations of oil-in-water emulsion stabilized by different hydrophobic maize starches.

    Science.gov (United States)

    Ye, Fan; Miao, Ming; Jiang, Bo; Hamaker, Bruce R; Jin, Zhengyu; Zhang, Tao

    2017-06-15

    The molecular structure, rheological properties, microstructure and physical stability of oil-in-water emulsions using octenyl succinic-sugary maize soluble starch (OS-SMSS) were investigated and compared with two commercial OS-starches (HI-CAP 100 and Purity Gum 2000). The degree of substitution (DS), weight-average molecular weight (Mw) and z-root mean square radius of gyration (Rz) of OS-SMSS, HI-CAP 100 and Purity Gum 2000 were 0.0050, 223.4×10 5 g/mol and 38.8nm, 0.0037, 9.6×10 5 g/mol and 29.3nm, and 0.0031, 31.3×10 5 g/mol and 39.6nm, respectively. FT-IR spectra showed two new absorption bands at 1725 and 1570cm -1 from OS ester linkage in all tested samples. The emulsion with OS-SMSS exhibited a pseudoplastic behavior over the whole shear rate range, whereas other two emulsions showed a similar Newtonian fluid. All hydrophobic starch stabilized emulsions satisfied the Herschel-Bulkley model. All emulsions displayed storage modulus (G') was higher than loss modulus (G″), and only G' and G″ of OS-SMSS stabilized emulsion were independent of frequency. The volume-average droplet size (d 43 ) value of emulsions stabilized by three modified starches was 27.9, 15.2 and 24.4μm, respectively. During 4 weeks storage, lower change in d 43 of emulsion with OS-SMSS was observed. The above results with schematic models of emulsions suggested that an emulsion with high stability could be prepared using 3% of OS-SMSS due to the formation of high density and thick nanoparticle layer at the interface, indicating OS-SMSS was a Pickering emulsion stabilizer for good long-term stability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Plant wide chemical water stability modelling with PHREEQC for drinking water treatment

    OpenAIRE

    Van der Helm, A.W.C.; Kramer, O.J.I.; Hooft, J.F.M.; De Moel, P.J.

    2015-01-01

    In practice, drinking water technologists use simplified calculation methods for aquatic chemistry calculations. Recently, the database stimela.dat is developed especially for aquatic chemistry for drinking water treatment processes. The database is used in PHREEQC, the standard in geohydrology for calculating chemical equilibria in groundwater. The development of a graphical user interface for PHREEQC in Microsoft Excel has made it possible to easily incorporate complicated chemical calculat...

  9. Sapropterin therapy increases stability of blood phenylalanine levels in patients with BH4-responsive phenylketonuria (PKU).

    Science.gov (United States)

    Burton, Barbara K; Bausell, Heather; Katz, Rachel; Laduca, Holly; Sullivan, Christine

    2010-01-01

    It has recently been demonstrated that variability in blood phenylalanine levels is inversely correlated with IQ and is a better predictor of IQ in early and continuously treated patients with phenylketonuria (PKU) than mean blood phenylalanine levels. This suggests that stability of blood phenylalanine should be a therapeutic goal in patients with PKU. The purpose of this study was to determine if treatment with sapropterin in patients with BH4-responsive PKU would increase the stability of blood phenylalanine levels. The records of all patients treated with sapropterin in the PKU Clinic at Children's Memorial Hospital in Chicago were examined retrospectively. Patients were included in the study if they were responsive to sapropterin during a 2- to 4-week challenge (reduction of blood phenylalanine level of at least 25% after 2weeks of therapy or, in the case of patients with well-controlled blood phenylalanine at the time of testing, increased dietary phenylalanine tolerance by 4weeks of treatment). A total of 37 subjects were eligible for inclusion (16male; 21 female); the mean age was 12.6years (range, 1.5-32.0). The total number of observations (phenylalanine levels) for all subjects was 1391 with a mean of 39 per subject (range, 13-96). Linear mixed modeling was utilized to estimate variances of the blood phenylalanine before (pre) and after (post) starting sapropterin. Likelihood ratio test was performed using SAS 9.1. Means and standard deviations for phenylalanine as estimated by the model were 6.67mg/dl (4.20) and post 5.16 (3.78). The mean level post-sapropterin was significantly lower (p=.0002). The within-subject variances (mean and SD) of phenylalanine were: pre 6.897 (2.62) and post 4.799 (2.19). These two variances are significantly different with a p=.0017. We conclude that sapropterin therapy results in increased stability of blood phenylalanine levels. This effect is likely to improve cognitive outcome in BH4-responsive patients with PKU

  10. High level model predictive control for plug-and-play process control with stability guaranty

    DEFF Research Database (Denmark)

    Michelsen, Axel Gottlieb; Stoustrup, Jakob

    2010-01-01

    In this paper a method for designing a stabilizing high level model predictive controller for a hierarchical plug- and-play process is presented. This is achieved by abstracting the lower layers of the controller structure as low order models with uncertainty and by using a robust model predictive...... controller for generating the references for these. A simulation example, in which the actuators in a process control system are changed, is reported to show the potential of this approach for plug and play process control....

  11. Coupling of sea level and tidal range changes, with implications for future water levels.

    Science.gov (United States)

    Devlin, Adam T; Jay, David A; Talke, Stefan A; Zaron, Edward D; Pan, Jiayi; Lin, Hui

    2017-12-05

    Are perturbations to ocean tides correlated with changing sea-level and climate, and how will this affect high water levels? Here, we survey 152 tide gauges in the Pacific Ocean and South China Sea and statistically evaluate how the sum of the four largest tidal constituents, a proxy for the highest astronomical tide (HAT), changes over seasonal and interannual time scales. We find that the variability in HAT is significantly correlated with sea-level variability; approximately 35% of stations exhibit a greater than ±50 mm tidal change per meter sea-level fluctuation. Focusing on a subset of three stations with long records, probability density function (PDF) analyses of the 95% percentile exceedance of total sea level (TSL) show long-term changes of this high-water metric. At Hong Kong, the increase in tides significantly amplifies the risk caused by sea-level rise. Regions of tidal decrease and/or amplification highlight the non-linear response to sea-level variations, with the potential to amplify or mitigate against the increased flood risk caused by sea-level rise. Overall, our analysis suggests that in many regions, local flood level determinations should consider the joint effects of non-stationary tides and mean sea level (MSL) at multiple time scales.

  12. Water levels and water quality in the Mississippi River Valley alluvial aquifer in eastern Arkansas, 2012

    Science.gov (United States)

    Schrader, Tony P.

    2015-01-01

    During the spring of 2012, the U.S. Geological Survey, in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey, measured water levels in 342 wells completed in the Mississippi River Valley alluvial aquifer in eastern Arkansas. The Arkansas Natural Resources Commission measured water levels in 11 wells, and the U.S. Department of Agriculture-Natural Resources Conservation Service measured water levels in 239 wells completed in the alluvial aquifer and provided these data to the Arkansas Natural Resources Commission. In 2010, estimated water withdrawals from the alluvial aquifer in Arkansas totaled about 7,592 million gallons per day. Withdrawals more than doubled between 1985 and 2010, about a 115-percent increase.

  13. Fluctuations of Lake Orta water levels: preliminary analyses

    Directory of Open Access Journals (Sweden)

    Helmi Saidi

    2016-04-01

    Full Text Available While the effects of past industrial pollution on the chemistry and biology of Lake Orta have been well documented, annual and seasonal fluctuations of lake levels have not yet been studied. Considering their potential impacts on both the ecosystem and on human safety, fluctuations in lake levels are an important aspect of limnological research. In the enormous catchment of Lake Maggiore, there are many rivers and lakes, and the amount of annual precipitation is both high and concentrated in spring and autumn. This has produced major flood events, most recently in November 2014. Flood events are also frequent on Lake Orta, occurring roughly triennially since 1917. The 1926, 1951, 1976 and 2014 floods were severe, with lake levels raised from 2.30 m to 3.46 m above the hydrometric zero. The most important event occurred in 1976, with a maximum level equal to 292.31 m asl and a return period of 147 years. In 2014 the lake level reached 291.89 m asl and its return period was 54 years. In this study, we defined trends and temporal fluctuations in Lake Orta water levels from 1917 to 2014, focusing on extremes. We report both annual maximum and seasonal variations of the lake water levels over this period. Both Mann-Kendall trend tests and simple linear regression were utilized to detect monotonic trends in annual and seasonal extremes, and logistic regression was used to detect trends in the number of flood events. Lake level decreased during winter and summer seasons, and a small but statistically non-significant positive trend was found in the number of flood events over the period. We provide estimations of return period for lake levels, a metric which could be used in planning lake flood protection measures.

  14. Total Water Level Fun Facts: The Relative Contribution of Extreme Total Water Levels Along the US West Coast

    Science.gov (United States)

    Serafin, K.; Ruggiero, P.; Stockdon, H. F.

    2016-02-01

    In the fall of 2014, parts of the US West Coast endured some of the highest monthly mean sea level anomalies on record, likely due to the presence of "the blob" (Bond et al., 2015), an anomalously warm water mass in the NE Pacific. However, despite the significantly above average water levels, the coastline experienced only marginal coastal flooding and erosion hazards because the ensuing winter lacked significant storms, underscoring the fact that extreme total water levels (TWLs) are compound events. To better understand how several individual processes combine to cause devastating coastal hazards, we investigate the relative contribution that each component (waves, tides, and non-tidal residuals) has on extreme TWLs on sandy beaches. Water level records along the US West Coast are decomposed into mean sea level, astronomical tide, and non-tidal residuals (NTRs). The NTR is further split into an intra-annual seasonal signal, monthly mean sea level anomalies (inter-annual variability), and meteorological surge. TWL time series are then generated by combining water levels with wave runup, computed using wave data and beach morphology. We use this data-driven, structural function approach to investigate the spatial variability of the relative contribution of each component to the maximum TWL event on record. We also use a probabilistic, full simulation TWL model (Serafin and Ruggiero, 2014) to generate multiple, synthetic TWL records, to explore the relative contribution of each component to extreme TWL return levels. We assess the sensitivity to local beach morphology by computing TWLs for a range of observed beach slopes. Extreme TWLs are higher in Oregon and Washington than in California. Wave runup typically comprises > 50% of the TWL signal, while NTRs often compose < 5%, illustrating the importance wave climate has on the potential for extreme TWLs. While waves are typically larger in the North, California experiences greater contributions to extreme TWLs from

  15. Concurrent temporal stability of the apparent electrical conductivity and soil water content

    Science.gov (United States)

    Pedrera-Parrilla, Aura; Pachepsky, Yakov A.; Taguas, Encarnación V.; Martos-Rosillo, Sergio; Giráldez, Juan V.; Vanderlinden, Karl

    2017-01-01

    Knowledge of spatio-temporal soil-water content (SWC) variability in agricultural fields is useful for improving crop management. Spatial patterns of SWC can be characterized using temporal stability analysis of difficult-to-obtain data from high spatial density and temporal frequency. Soil apparent electrical conductivity (ECa) measurements with high spatial density have been widely used to infer the spatial variability of SWC. The objective of this work is to test the hypothesis that temporal stability of ECa can be demonstrated and that relationships between temporal stability characteristics of SWC and ECa can be established. Apparent electrical conductivity and topsoil gravimetric SWC (θ) were periodically measured in an olive orchard in southwest Spain on 6 and 18 occasions, respectively. A temporal stability analysis of ECa elucidated three zones where ECa was close to, consistently substantially smaller than, and substantially larger than the spatial average ECa throughout the study period. Representative locations for θ were found with a chance of 75% within the representative zone for ECa. Yet, the driest locations, with consistently smaller θ than the field average (〈 θ 〉), could be successfully identified (89%) within the zone with consistently smaller ECa than average. The θ - 〈 θ 〉 relations showed generally a linear behaviour, although a better fit was obtained at the highest θ using either exponential or power law equations at half of the locations. The former provided the best fit within the zone with ECa consistently smaller than average, while the latter performed best in the zone with ECa consistently larger than average. The linear equation provided the best fit within the representative ECa zone. This study demonstrates that temporal stability characteristics of ECa and SWC are linked and that ECa surveys can be used to delimit zones with representative locations for SWC measurement or estimation. Such information is of

  16. The stability and removal of water-dispersed CdSe/CdS core-shell quantum dots from water.

    Science.gov (United States)

    Chen, Xu; Ok, Yong Sik; Mohan, Dinesh; Pittman, Charles U; Dou, Xiaomin

    2017-10-01

    The increasingly wide use of semiconductor nanocrystals inevitably leads to their release into aquatic environment. The aggregation behaviors of 3-mercaptopropionic acid-capped CdSe/CdS core-shell quantum dots (MPA-QDs) under various water chemistry conditions were examined and their removal using Fe 3+ and Al 3+ coagulants was evaluated. Cationic species rather than concentrations affected the stability of MPA-QDs. Adding 2 mM Ca 2+ led to a much larger ζ-potential decrease and particle size increase than adding 150 mM K + at each tested solution pH. This indicated that complexation and depletion of surface-bound carboxyl groups by divalent Ca 2+ has a more pronounced effect than compression of the electrical double layer by high concentrations of monovalent K + . The presence of humic acid increased the stability of MPA-QDs, which might increase negative surface charging via overcoating or bind to the surface of MPA-QDs. The nanoparticles exhibited similar aggregation kinetics patterns in tap water and seawater, but varying patterns in the lake water because of the co-existence of 2.3 mM total of Ca 2+ and Mg 2+ . MPA-QDs (5 mg L -1 ) were readily coagulated by 2.4 mM Al 3+ or 1.2 mM Fe 3+ in tap water. Al 3+ and Fe 3+ can bind with carboxyl groups of the surface capping ligands, neutralize the negative charges on the surface of MPA-QDs and decrease the electrostatic repulsion forces to induce MPA-QDs aggregation. In addition, MPA-QDs could be bound with and wrapped into the flocs of hydrolysis products of coagulants. The results reported here could help broaden our understanding of the impacts and remediation of water-dispersed core-shell QD nanoparticles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Water-stability of soil aggregates in relation to selected properties

    International Nuclear Information System (INIS)

    Mbagwu, J.S.C.; Bazzoffi, P.; Unamba Oparah, I.

    1995-03-01

    The stability of soil aggregates in water is an important soil physical property for evaluating the potential of agricultural soils to erode and elucidating the mechanisms of soil erosion. In this study we used aggregates from 15 surface soil samples in Italy to evaluate the influence of intrinsic soil physical, chemical and mineralogical properties on aggregates stability (AS). The aim was to develop a model for predicting AS from a subset of these soil properties. The index of stability used is the mean-weight diameter of water-stable aggregates (MWD). The model developed with soil physical properties alone explained just 42% of variance in MWD and predicted AS in only 20% of test soils. The model developed with mineralogical properties alone explained 70% of variance in MWD and predicted AS in 60% of the test soils. The chemical properties - based model explained 90% of variance in MWD and predicted AS in 80% of the test soils. The best-fit model was developed with soil properties from the physical, chemical and mineralogical subsets. It explained 98% of variance in MWD and predicted AS in 100% of the test soils. This model shows that the most important soil properties which influence the AS of these soils include ratio of total sand to clay, concentrations of iron oxide, magnesium oxide, organic matter, silica/alumina ratio, chlorite, feldspar and muscovite. This indicates that fairly good estimates of the relative stability of these aggregates in water and hence of their potential to erode, requires a knowledge of the physico-chemical and mineralogical properties. (author). 40 refs, 4 tabs

  18. Water-soluble and solid-state speciation of phosphorus in stabilized sewage sludge.

    Science.gov (United States)

    Huang, Xiao-Lan; Shenker, Moshe

    2004-01-01

    Three chemicals, ferrous sulfate (Fe-sul), calcium oxide (CaO), and aluminum sulfate (alum), were used to stabilize phosphorus (P) in fresh, anaerobically digested sewage sludge (FSS). The chemically stabilized sludge materials and biosolids compost (BSC) were compared with the FSS with respect to water-soluble phosphorus (WSP) content in its inorganic (WSP(i)) and organic (WSP(o)) forms as well as water-soluble organic carbon (DOC). Solid-state P speciation was further probed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive X-ray elemental spectrometry (EDXS). Water-soluble P was effectively controlled by a wide range of Fe-sul or CaO additions to the sludge (Ca to P ratio = 3.47-17.72, Fe to P ratio = 1.01-16.53), but by only a narrow range (Al to P ratio = 1.04-2.87) of alum addition. The WSP content in the BSC was also depressed, but to a lesser extent. The pH in the treated sludge ranged from 3.0 to 12.5 and served as a key factor to control P chemistry. No correlation was observed between DOC and WSP(o). No crystallized Ca-P minerals were detected in the CaO-stabilized sludge, but brushite crystallization seemed to be obtained by low addition of Fe-sul and alum. Variscite and strengite crystallization was obtained following high addition of Fe-sul or alum, as detected by XRD and SEM-EDXS. Adsorption of P by newly formed Fe-hydroxide seems to play an important role in the Fe-sul-stabilized sludge. We concluded that administration of the tested chemicals at the proper rate can effectively reduce the hazard of P release and leaching from sludge.

  19. Impact of water saturation level on arsenic and metal mobility in the Fe-amended soil.

    Science.gov (United States)

    Kumpiene, Jurate; Ragnvaldsson, Daniel; Lövgren, Lars; Tesfalidet, Solomon; Gustavsson, Björn; Lättström, Anders; Leffler, Per; Maurice, Christian

    2009-01-01

    The impact of water saturation level (oxidizing-reducing environment) on As and metal solubility in chromium, copper, arsenic (CCA)-contaminated soil amended with Fe-containing materials was studied. The soil was mixed with 0.1 and 1 wt% of iron grit (Fe(0)) and 1, 7 and 15 wt% of oxygen scarfing granulate (OSG, a by-product of steel processing). Solubility of As and metals was evaluated by a batch leaching test and analysis of soil pore water. Soil saturation with water greatly increased As solubility in the untreated as well as in the Fe-amended soil. This was related to the reductive dissolution of Fe oxides and increased concentration of As(III) species. Fe amendments showed As reducing capacity under both oxic and anoxic conditions. The cytotoxicity of the soil pore water correlated with the concentration of As(III). The Fe-treatments as well as water saturation of soil were less significant for the solubility of Cu, Cr and Zn than for As. The batch leaching test used for waste characterization substantially underestimated As solubility that could occur under water-saturated (anaerobic) conditions. In the case of soil landfilling, other techniques than Fe-stabilization of As containing soil should be considered.

  20. Analysis of green tea compounds and their stability in dentifrices of different pH levels.

    Science.gov (United States)

    Jang, Jong-Hwa; Park, Yong-Duk; Ahn, Hyo-Kwang; Kim, Seung-Jin; Lee, Joo-Young; Kim, Eun-Cheol; Chang, Yeon-Soo; Song, Yun-Jung; Kwon, Ha-Jeong

    2014-01-01

    In this study, green tea compounds (flavonoids, alkaloids, and phenolic acids) were analyzed in green tea-containing dentifrices, and their stability at different pH levels was evaluated. The compounds were separated under 0.01% phosphoric acid-acetonitrile gradient conditions and detected by photodiode array detector at 210, 280, 300, 335 nm. Column temperature was set at 20°C based on the results of screening various temperatures. Each compound showed good linearity at optimized wavelength as well as showing good precision and accuracy in dentifrices. Using this method, the stability of compounds was investigated in pH 4, 7, 8, and 10 solutions for 96 h, and in pH 7 and pH 10 solutions for 6 months. The green tea compounds were more stable at low pH levels; purine alkaloids were more stable than flavonoids. In particular, gallocatechin (GC), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin gallate (GCG), and myricetin almost disappeared in pH 10 solutions after 96 h. In dentifrices, the compounds were gradually decreased until 6 months in both pH types, while gallic acid was increased because of production of galloyl ester of other green tea compounds. Therefore, it is beneficial to adjust to as low a pH as possible when produce green tea-containing dentifrices.

  1. Stabilization of heavy oil-water emulsions using a bio/chemical emulsifier mixture

    Energy Technology Data Exchange (ETDEWEB)

    Farahbakhsh, A.; Taghizadeh, M.; Movagharnejad, K. [Chemical Engineering Department, Babol University of Technology, Babol (Iran, Islamic Republic of); Yakhchali, B. [National Institute of Genetic Engineering and Biotechnology, Tehran (Iran, Islamic Republic of)

    2011-11-15

    In this study, the viscosity reduction of heavy oil has been investigated through the formation of oil-water emulsion using a bio/chemical emulsifier mixture. Four bioemulsifiers from indigenous Rhodococcus ergthropolis and Bacillus licheniformis strains were used to stabilize a highly-viscous oil-in-water emulsion. The Taguchi method with an L{sub 9} orthogonal array design was used to investigate the effect of various control factors on the formation of the oil/water emulsions. An emulsion with lowest viscosity was formed using ACO4 strain. The substantial stability of the oil-in-water emulsion allows the heavy oil to be transported practically over long distances or remain stationary for a considerable period of time prior to utilization. As the result of Taguchi analysis, the temperature and concentration of the emulsifier had a significant influence on viscosity reduction of the emulsion. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. A Fluorine-free Slippery Surface with Hot Water Repellency and Improved Stability against Boiling.

    Science.gov (United States)

    Togasawa, Ryo; Tenjimbayashi, Mizuki; Matsubayashi, Takeshi; Moriya, Takeo; Manabe, Kengo; Shiratori, Seimei

    2018-01-31

    Inspired by natural living things such as lotus leaves and pitcher plants, researchers have developed many excellent antifouling coatings. In particular, hot-water-repellent surfaces have received much attention in recent years because of their wide range of applications. However, coatings with stability against boiling in hot water have not been achieved yet. Long-chain perfluorinated materials, which are often used for liquid-repellent coatings owing to their low surface energy, hinder the potential application of antifouling coatings in food containers. Herein, we design a fluorine-free slippery surface that immobilizes a biocompatible lubricant layer on a phenyl-group-modified smooth solid surface through OH-π interactions. The smooth base layer was fabricated by modification of phenyltriethoxysilane through a sol-gel method. The π-electrons of the phenyl groups interact with the carboxyl group of the oleic acid used as a lubricant, which facilitates immobilization on the base layer. Water droplets slid off the surface in the temperature range from 20 to 80 °C at very low sliding angles (boiling stability under hot water. We believe that this surface will be applied in fields in which the practical use of antifouling coatings is desirable, such as food containers, drink cans, and glassware.

  3. Effects of decreased ground-water withdrawal on ground-water levels and chloride concentrations in Camden County, Georgia, and ground-water levels in Nassau County, Florida, from September 2001 to May 2003

    Science.gov (United States)

    Peck, Michael F.; McFadden, Keith W.; Leeth, David C.

    2005-01-01

    During October 2002, the Durango Paper Company formerly Gillman Paper Company) in St. Marys, Georgia, shut down paper-mill operations; the shutdown resulted in decreased ground-water withdrawal in Camden County by 35.6 million gallons per day. The decrease in withdrawal resulted in water-level rise in wells completed in the Floridan aquifer system and the overlying surficial and Brunswick aquifer systems; many wells in the St. Marys area flowed for the first time since the mill began operations during 1941. Pumping at the mill resulted in the development of a cone of depression that coalesced with a larger adjacent cone of depression at Fernandina Beach, Florida. Since closure of the mill, the cone at St. Marys is no longer present, although the cone still exists at Fernandina Beach, Florida. Historical water-level data from the production wells at the mill indicate that the pumping water level ranged from 68 to 235 feet (ft) below North American Vertical Datum of 1988 (NAVD 88) and averaged about 114 ft when the mill was operating. Since the shutdown, it is estimated that water levels at the mill have risen about 140 ft and are now at about 30 ft above NAVD 88. The water-level rise in wells in outlying areas in Camden County was less pronounced and ranged from about 5 to 10 ft above NAVD 88. Because of the regional upward water-level trend in the Upper Floridan aquifer that started during 19992000 in most of the coastal area, combined with a steeper upward trend beginning during October 2002, it was not possible to determine if the 510 ft rise in water levels in wells away from St. Marys was due to the mill closure. In addition to water-level rise of 2226 ft in the Floridan aquifer system, water-level rises in the overlying surficial and Brunswick aquifer systems at St. Marys after the shutdown indicate upward leakage of water. Water levels had stabilized in the confined surficial and Upper and Lower Floridan aquifers by AprilMay 2003; however, the water level in

  4. Regulation of the water level in the steam generator using modal control

    International Nuclear Information System (INIS)

    Benoit, Guy.

    1981-11-01

    The nuclear power reactors type P.W.R. (900 MWe) have three steam generators (S.G.). The problem of the water level in the S.G. is analogous to that for a system with non-minimum phase. This causes a serious trouble for the stability of the regulation, which is actually realized by using the PID regulator. The first part of this study is devoted to construct a mathematical model which represents the S.G. This model is simulated on a digital computer, which order is six. The validity of this model is checked using actual measured signals which have been collected from the BUGEY III power reactor. In the second part, the mathematical representation for simulating the regulation of the level in the S.G. using the modal control is given. The simulation of the actual system is given in the third part. This actual system is composed from the S.G. as well as the PI and PID for regulating the water level. As results from this study, it can be concluded that, the modal control improves the regulation of the water level. The accuracy of the steam flow measurement at low rate is poor. So, the actual regulating system using the measurements has a reduced performance performance. The control modal which is represented in this study overcome this problem [fr

  5. Effect of dispersing and stabilizing additives on rheological characteristics of the upgraded brown coal water mixture

    International Nuclear Information System (INIS)

    Umar, Datin Fatia; Muta'alim; Usui, Hiromoto; Komoda, Yoshiyuki

    2009-01-01

    Upgraded brown coal water mixture (UBCWM) preparation by using an Indonesian upgraded coal produced by upgraded brown coal (UBC) process, was carried out to study the effect of dispersing and stabilizing additives on rheological behavior of the UBCWM. Three kinds of anionic dispersing additives, naphthalene sulfonic formaldehyde condensate (NSF), poly (meth) acrylate (PMA) and poly styrene sulfonic acid (PSS) and three kinds of stabilizing additives, carboxyl methyl cellulose (CMC), rhansam gum (S-194) and gellan gum (S-60) were used in this study. Results indicate that the addition of NSF 0.3 wt.% together with S-194 0.01 wt.% is effective in preparing UBCWM with good slurryability and stability, based on its rheological characteristics with the apparent viscosity at shear rate of 100 s - 1 and yield stress at zero point of shear rate. The rheological behavior of all of the UBCWM that prepared, exhibits non-Newtonian Bingham plastic. From the economical point of view, the price of S-194 is expensive. On the other hand, CMC is cheap and abundant. Therefore, the addition of CMC 0.01 wt.% together with NSF 0.3 wt.% is also effective in preparing UBCWM with good fluidity and stability. (author)

  6. Stabilization of lead-rich low-level mixed waste in chemically bonded phosphate ceramic

    International Nuclear Information System (INIS)

    Jeong, S.-Y.

    1999-01-01

    A chemically bonded magnesium potassium phosphate ceramic has been developed by an acid-base reaction at room temperature, for use in stabilizing U.S. Department of Energy low-level mixed waste streams that include hazardous metals and low-level radioactive elements. Using this ceramic, we solidified, in monolithic waste forms, low-level mixed waste streams containing various levels of PbCl 2 and PbCO 3 . These final waste forms were evaluated for their land disposal suitability. The results showed low open porosity (1.48-4.61 vol.%); hence, low permeability, and higher compression strengths (4310-6734 psi) that were one order of magnitude above that required. The level of lead in the leachate following the Toxicity Characteristic Leaching Procedure test was reduced from 50,000 to <0.1 ppm. Leachability indexes from the long-term leaching test (ANS 16.1 test) were between 11.9 and 13.6. This excellent lead retention is due to its chemical fixation as insoluble lead phosphate and to physical encapsulation by the phosphate matrix

  7. Correlation analysis of levels of adiponectin and matrix metalloproteinase-9 with stability of coronary heart disease.

    Science.gov (United States)

    Li, Ya

    2015-01-01

    To analyze the changes of adiponection (ANP) and matrix metalloproteinase-9 (MMP-9) in patients with coronary heart diseases (CHD) of different types, to investigate the correlation between these changes and stability of coronary artery plague. Inpatients of our hospital were divided into 56 cases with acute myocardial infarction (AMI), 56 cases with unstable angina pectoris (UA), 54 cases with stable angina pectoris (SA), and 60 cases with CHD excluded by using coronary arteriongraphy as the control group. Changes of ANP and MMP-9 were determined, and the correlation was analyzed. 1. ANP and MMP-9 levels in CHD group were higher than those of control group (P < 0.01). 2. Serum ANP and MMP-9 levels in AMI and UA groups were significantly higher than those in control group and SA group (P < 0.05). 3. MMP-9 level in AMI group was significantly higher than that in UA group (P < 0.01). 1. Increased ANP and MMP-9 levels are the independent risk factors of CHD; 2. Increased levels of ANP and MMP-9 in patients with CHD suggest instability of atherosclerotic plaque.

  8. [Residual levels of acetochlor in source water and drinking water of China's major cities].

    Science.gov (United States)

    Yu, Zhi-Yong; Jin, Fen; Li, Hong-Yan; An, Wei; Yang, Min

    2014-05-01

    The concentration levels of acetochlor were investigated in source water and drinking water from 36 major cities in China by solid phase extraction (SPE) combined with gas chromatography - mass spectrometry (GC-MS). Acetochlor detection rate was 66.9% in all the 145 source water samples collected with an average concentration of 33.9 ng L-1. The average removal rate of acetochlor was limited through the drinking water treatment process. The detection concentration of the northeast region was the highest. The concentrations of acetochlor detected in lake were higher than those in river and groundwater as source water. The detection rate and concentration of Liaohe river watershed and the coastal watershed were the highest.

  9. Study of Water-Oil Emulsion Breaking by Stabilized Solution Consisting of Anionic Surface Acting Agent - Soda Ash - Polymer (ASP)

    Science.gov (United States)

    Kulichkov, S. V.; Avtomonov, E. G.; Andreeva, L. V.; Solomennik, S. F.; Nikitina, A. V.

    2018-01-01

    The paper provides a laboratory research of breaking natural water-oil emulsions: - by non-stabilized ASP; by stabilized ASP; by mixture of stabilized and non-stabilized ASP in different proportions and production of refinery water of the required quality with the use of IronGuard 2495 as flocculant. Oil-in-water emulsion is stable. Classic methods are not suitable for residual water treatment: sediment gravity flow; filtration; centrifuge test. Microemulsion formed after ASP application has low boundary tension and high pH. It contributes to transfer of oil phase into a water one, forming oil-in-water emulsion. Alkaline condition has adverse effect on demulsifying ability of agents, flocculation and boundary tension. For breaking of water-oil emulsion at EBU before the interchanger water or water-oil emulsion from the wells that were not APS-treated in ratio of 1:9 shall be delivered. Residual water after EBU must be prepared in water tanks by dilution in great volume.

  10. Structure stability and water retention near saturation characteristics as affected by soil texture, and polyacrylamide concentration

    Science.gov (United States)

    Mamedov, Amrakh I.; Ekberli, Imanverdi A.; Ozturk, Hasan S.; Wagner, Larry E.; Norton, Darrell L.; Levy, Guy J.

    2017-04-01

    Studying the effects of soil properties and amendment application on soil structure stability is important for the development of effective soil management and conservation practices for sustaining semi-arid soil and water quality under climate change scenarios. Two sets of experiments were conducted to evaluate the effects of soil texture and soil amendment polyacrylamide (PAM) rate on soil structural stability expressed in terms of near saturation soil water retention and aggregate stability using the high energy (0-5 J kg-1) moisture characteristic (HEMC) method. Contribution of (i) soil type were assessed using 30 soil samples varying in texture from sandy to clay taken from long term cultivated lands, covering a range of crop and land management practices, and (ii) anionic PAM concentration (0, 10, 25, 50, 100 & 200 mg l-1) were tested on selected loam and clay soils. The water retention curves of slow and fast wetted soil samples were characterized by a modified van Genuchten (1980) model that provides (i) model parameters α and n, which represent the location of the inflection point and the steepness of the S-shaped water retention curves, and (ii) a composite soil structure index (SI =VDP/MS; VDP-volume of drainable pores, MS-modal suction). The studied treatments had, generally, considerable effects on the shape of the water retention curves (α and n). Soil type, PAM concentration and their interaction had significantly effects on the stability indices (SI, VDP and MS) and the model parameters (α and n). The SI and α increased, and ndecreased exponentially with the increase in soil clay content and PAM concentration, but the shape of curves were soil texture and management dependent, since predominant changes were observed in the various range of studied macropores (pore size > 60 μm). An exponential type of relationship existed between SI and α and n. Effect of PAM contribution and wetting condition was more pronounced in the loam soil at low PAM

  11. Zwitterionization of glycine in water environment: Stabilization mechanism and NMR spectral signatures

    Science.gov (United States)

    Valverde, Danillo; da Costa Ludwig, Zélia Maria; da Costa, Célia Regina; Ludwig, Valdemir; Georg, Herbert C.

    2018-01-01

    At physiological conditions, myriads of biomolecules (e.g., amino acids, peptides, and proteins) exist predominantly in the zwitterionic structural form and their biological functions will result in these conditions. However these geometrical structures are inaccessible energetically in the gas phase, and at this point, stabilization of amino-acids in physiological conditions is still under debate. In this paper, the electronic properties of a glycine molecule in the liquid environment were studied by performing a relaxation of the glycine geometry in liquid water using the free energy gradient method combined with a sequential quantum mechanics/molecular mechanics approach. A series of Monte Carlo Metropolis simulations of the glycine molecule embedded in liquid water, followed by only a quantum mechanical calculation in each of them were carried out. Both the local and global liquid environments were emphasized to obtain nuclear magnetic resonance (NMR) parameters for the glycine molecule in liquid water. The results of the equilibrium structure in solution and the systematic study of the hydrogen bonds were used to discard the direct proton transfer from the carboxyl group to the ammonium group of the glycine molecule in water solution. The calculations of the Density Functional Theory (DFT) were performed to study the polarization of the solvent in the parameters of nuclear magnetic resonance of the glycine molecule in liquid water. DFT calculations predicted isotropic chemical changes on the H, C, N, and O atoms of glycine in liquid water solution which agree with the available experimental data.

  12. Influence of cryoprotectant levels on storage stability of surimi from Nemipterus japonicus and quality of surimi-based products.

    Science.gov (United States)

    U, Parvathy; George, Sajan

    2014-05-01

    A study was undertaken with the aim of reducing the concentration of cryoprotectants in surimi without adversely affecting frozen storage stability. Minced meat from a tropical fish, Nemipterus japonicus, was strained, water leached and mixed with different levels of sucrose-sorbitol (1:1) mixture (henceforth called sugar mixture), quick frozen at -35 °C and frozen stored at -20 °C. The surimi samples were subjected to storage stability studies for a period of 5 months. Water leaching resulted in slight absorption of water by meat and reduction in protein, fat and mineral contents. Surimi was found to have moderately white colour. Sensory evaluation studies were conducted on three products, viz., sausage, patty and cake, prepared using surimi containing different concentrations of sugar mixture. Sugar mixture content varying from 0% (control) to 4% in surimi resulted in products that were more acceptable to the taste panelists compared those with 6% and 8% sugar mixture. During frozen storage of surimi pH and total plate count remained nearly steady for all sugar mixture concentrations and throughout the storage period. Moisture content appeared to remain constant during storage, but decreased with increase in sugar concentration. The salt soluble nitrogen content of surimi and gel strength of sausage prepared from it decreased with storage period in all surimi samples, and increased with sugar mixture concentration. Expressible water content of surimi sausage showed an increasing trend with storage period of surimi and a decreasing trend with sugar mixture concentration. Sensory evaluation parameters-elasticity, sweetness and preference-remained more or less steady during storage. However elasticity and sweetness increased and preference decreased with sugar mixture concentration beyond 4%. Elasticity and gel strength of surimi sausage seemed to be much lower for control compared to even the lowest concentration of sugar (2%) used. A concentration of 2 to 4

  13. A Simple Approach to Enhance the Water Stability of a Metal-Organic Framework.

    Science.gov (United States)

    Shih, Yung-Han; Kuo, Yu-Ching; Lirio, Stephen; Wang, Kun-Yun; Lin, Chia-Her; Huang, Hsi-Ya

    2017-01-01

    A facile method to improve the feasibility of water-unstable metal-organic frameworks in an aqueous environment has been developed that involves imbedding in a polymer monolith. The effect of compartment type during polymerization plays a significant role in maintaining the crystalline structure and thermal stability of the MOFs, which was confirmed by powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA), respectively. The MOF-polymer composite prepared in a narrow compartment (column, ID 0.8 mm) has better thermal and chemical stability than that prepared in a broad compartment (vial, ID 7 mm). The developed MOF-polymer composite was applied as an adsorbent in solid-phase microextraction of nine non-steroidal anti-inflammatory drugs (NSAIDs) and could be used for extraction more than 30 times, demonstrating that the proposed approach has potential for industrial applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Amino acids as co-amorphous stabilizers for poorly water-soluble drugs - Part 2

    DEFF Research Database (Denmark)

    Löbmann, K.; Laitinen, R.; Strachan, C.

    2013-01-01

    The formation of co-amorphous drug-drug mixtures has proved to be a powerful approach to stabilize the amorphous form and at the same time increase the dissolution of poorly water-soluble drugs. Molecular interactions in these co-amorphous formulations can play a crucial role in stabilization...... spectroscopy. Molecular interactions of the drugs carbamazepine and indomethacin with the amino acids arginine, phenylalanine, and tryptophan were investigated. The amino acids were chosen from the biological target site of both drugs and prepared as co-amorphous formulations together with the drugs...... that the drugs formed specific molecular interactions (hydrogen bonding and π-π interactions) with the amino acids. In the drug-amino acid mixtures that contained amino acids which were not present at the biological target site, no such interactions were identified. This study shows the potential of amino acids...

  15. Influence of Carbon Nanotubes on Thermal Stability of Water-Dispersible Nanofibrillar Polyaniline/Nanotube Composite

    Directory of Open Access Journals (Sweden)

    Zhi-Bin Zhang

    2012-02-01

    Full Text Available Significant influence on the thermal stability of polyaniline (PANI in the presence of multi-walled carbon nanotubes (MWCNTs is reported. By means of in-situ rapid mixing approach, water-dispersible nanofibrillar PANI and composites, consisting of MWCNTs uniformly coated with PANI in the state of emeraldine salt, with a well-defined core-shell heterogeneous structure, were prepared. The de-protonation process in PANI occurs at a lower temperature under the presence of MWCNTs on the polyaniline composite upon thermal treatment. However, it is found that the presence of MWCNTs significantly enhances the thermal stability of PANI’s backbone upon exposure to laser irradiation, which can be ascribed to the core-shell heterogeneous structure of the composite of MWCNTs and PANI, and the high thermal conductivity of MWCNTs.

  16. Relative Sea Level, Tidal Range, and Extreme Water Levels in Boston Harbor from 1825 to 2016

    Science.gov (United States)

    Talke, S. A.; Kemp, A.; Woodruff, J. D.

    2017-12-01

    Long time series of water-level measurements made by tide gauges provide a rich and valuable observational history of relative sea-level change, the frequency and height of extreme water levels and evolving tidal regimes. However, relatively few locations have available tide-gauge records longer than 100 years and most of these places are in northern Europe. This spatio-temporal distribution hinders efforts to understand global-, regional- and local-scale trends. Using newly-discovered archival measurements, we constructed a 200 year, instrumental record of water levels, tides, and storm surges in Boston Harbor. We detail the recovery, datum reconstruction, digitization, quality assurance, and analysis of this extended observational record. Local, decadally-averaged relative sea-level rose by 0.28 ± 0.05 m since the 1820s, with an acceleration of 0.023 ±0.009 mm/yr2. Approximately 0.13 ± 0.02 m of the observed RSL rise occurred due to ongoing glacial isostatic adjustment, and the remainder occurred due to changes in ocean mass and volume associated with the onset of modern mean sea-level rise. Change-point analysis of the new relative sea level record confirms that anthropogenic rise began in 1924-1932, which is in agreement with global mean sea level estimates from the global tide gauge network. Tide range decreased by 5.5% between 1830 and 1910, likely due in large part to anthropogenic development. Storm tides in Boston Harbor are produced primarily by extratropical storms during the November-April time frame. The three largest storm tides occurred in 1851, 1909, and 1978. Because 90% of the top 20 storm tides since 1825 occurred during a spring tide, the secular change in tide range contributes to a slight reduction in storm tide magnitudes. However, non-stationarity in storm hazard was historically driven primarily by local relative sea-level rise; a modest 0.2 m increase in relative sea level reduces the 100 year high water mark to a once-in-10 year event.

  17. Enhancing the natural folate level in wine using bioengineering and stabilization strategies.

    Science.gov (United States)

    Liu, Yazheng; Walkey, Christopher J; Green, Timothy J; van Vuuren, Hennie J J; Kitts, David D

    2016-03-01

    Folate deficiency is linked to many diseases, some of which may have higher probability in individuals with alcohol-induced alterations in one-carbon metabolism. Our study shows that folate content in commercial wine is not related to white or red varieties, but associated with the yeast that is used to produce the wine. The stability of folate in these wines, once opened for consumption, did not correlate with total phenolic or sulfite content. In addition, we employed yeast bioengineering to fortify wine with folate. We confirmed by overexpression that FOL2 was the key gene encoding the rate-limiting step of folate biosynthesis in wine yeast. In this study, we also show that overexpression of other folate biosynthesis genes, including ABZ1, ABZ2, DFR1, FOL1 and FOL3, had no effect on folate levels in wine. Ensuring stability of the increased natural folate in all wines was achieved by the addition of ascorbate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Hillslope scale temporal stability of soil water storage in diverse soil layers

    Science.gov (United States)

    Jia, Xiaoxu; Shao, Ming'an; Wei, Xiaorong; Wang, Yunqiang

    2013-08-01

    Knowledge of the soil water storage (SWS) of soil profiles on the scale of a hillslope is important for the optimal management of soil water and revegetation on sloping land in semi-arid areas. This study aimed to investigate the temporal stability of SWS profiles (0-1.0, 1.0-2.0, and 2.0-3.0 m) and to identify representative sites for reliably estimating the mean SWS on two adjacent hillslopes of the Loess Plateau in China. We used two indices: the standard deviation of relative difference (SDRD) and the mean absolute bias error (MABE). We also endeavored to identify any correlations between temporal stability and soil, topography, or properties of the vegetation. The SWS of the soil layers was measured using neutron probes on 15 occasions at 59 locations arranged on two hillslopes (31 and 28 locations for hillslope A (HA) and hillslope B (HB), respectively) from 2009 to 2011. The time-averaged mean SWS for the three layers differed significantly (P management of soil water on sloping land on the Loess Plateau.

  19. Development of cetyl dimethicone based water-in-oil emulsion containing botanicals: Physical characteristics and stability.

    Science.gov (United States)

    Waqas, Muhammad Khurram; Akhtar, Naveed; Shah, Pervaiz Akhtar; Danish, Muhammad Zeeshan; Shah, Arshad Ali; Braga, Valdir de Andrade; Khan, Barkat Ali

    2016-01-01

    The aim of current research was to develop a water-in-oil emulsion containing grape seed extract for application in cosmeceuticals. Finally grinded dried grape seeds powder was extracted with hydro alcoholic mixture. Emulsions consisting of different concentrations of cetyl dimethicone (Abile EM90), the nonionic emulsifier, liquid paraffin as oily phase and water as aqueous phase were developed. Color, odor, pH, viscosity, liquefaction, phase separation, centrifugation and thermal stability of the formulated emulsions were observed at various storage temperatures i.e. 8±0.5°C, 25±0.5°C, 40±0.5°C and 40°C±0.5°C with 70% RH. The stable formulation consist of 16% mineral oil, 4% of ABIL EM 90(®), 4% grape seeds extract, 1% rose oil and 75% distilled water. All the results derived from this study showed good stability over the three months study period which indicates w/o emulsion can be used as carrier of 4% grape seeds extract to enhance desired effects when applied topically.

  20. FEM for stability analysis against overturning of portal water injection sheet pile

    Science.gov (United States)

    Lingyun, Liu; Haiyan, Guo; Qi, Sun

    2006-07-01

    Portal water injection sheet pile (PWISP), as a retaining wall, appeared in seashore engineering in 2000. Although there have been many systematic methods addressing the issue, there are very few focusing on the new structure because of the difficulties in defining the earth pressure between the two piles. A new method is proposed in this paper to obtain the earth pressure between the PWISPs. Stability analysis against overturning follows as a consequence. Using Finite Element Analysis (FEA) software ANSYS, both the nonlinear characteristics of the soil and thos of the contact elements are taken into account to obtain the earth pressure distribution on the contact surface. Based on the results of the FEA, Rankin's theory and the slip plane theory, the formula of the earth pressure on the inner surfaces between the piles is given. Assuming the PWISP as the analysis object and the earth pressure as an outside force acting upon it, the equation of stability against overturning of the PWISP is presented. Finally, some parameters are discussed about the stability of the PWISP against overturning, such as the embedded depth of the front pile, the distance between the two rows of piles, the internal friction angle and the cohesion of the earth. The results show that the increase of the cohesion and the internal friction angle will decrease the distance and the embedded depth, and therefore enhance the stability against overturning. Specifically, when the distance is 1/3 2/3 of the maximal excavation depth, the two rows of piles give the best performance in stability.

  1. Global gray water footprint and water pollution levels related to anthropogenic nitrogen loads to fresh water

    NARCIS (Netherlands)

    Mekonnen, Mesfin; Hoekstra, Arjen Ysbert

    2015-01-01

    This is the first global assessment of nitrogen-related water pollution in river basins with a specification of the pollution by economic sector, and by crop for the agricultural sector. At a spatial resolution of 5 by 5 arc minute, we estimate anthropogenic nitrogen (N) loads to freshwater,

  2. Effects of Wood Pollution on Pore-Water Sulfide Levels and Eelgrass Germination

    Science.gov (United States)

    Ekelem, C.

    2016-02-01

    Historically, sawmills released wood waste onto coastal shorelines throughout the Pacific Northwest of the USA, enriching marine sediments with organic material. The increase in organic carbon boosts the bacterial reduction of sulfate and results in the production of a toxic metabolite, hydrogen sulfide. Hydrogen sulfide is a phytotoxin and can decrease the growth and survival of eelgrass. This is a critical issue since eelgrass, Zostera marina, forms habitat for many species, stabilizes sediment, and plays a role in nutrient cycling and sediment chemistry. The objective of our study was to determine the effects of wood debris on sediment pore-water hydrogen sulfide concentrations and eelgrass germination. To test the impact of wood inputs on sulfide production and seed germination, we conducted a laboratory mesocosm experiment, adding sawdust to marine sediments and measuring the sulfide levels weekly. We subsequently planted seeds in the mesocosms and measured germination rates. Higher concentrations of sawdust led to higher levels of pore-water hydrogen sulfide and drastically slower eelgrass germination rates. Treatments with greater than 10% wood enrichment developed free sulfide concentrations of 0.815 (± 0.427) mM after 118 days, suggesting sediments with greater than 10% wood pollution may have threateningly high pore-water hydrogen sulfide levels. These results can be used to set thresholds for remediation efforts and guide seed distribution in wood polluted areas.

  3. Formal specification and animation of a water level monitoring system

    International Nuclear Information System (INIS)

    Jackson, P.S.; Stokes, P.A.

    1993-03-01

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

  4. On the stability of Einstein static universe at background level in massive bigravity

    Directory of Open Access Journals (Sweden)

    M. Mousavi

    2017-06-01

    Full Text Available We study the static cosmological solutions and their stability at background level in the framework of massive bigravity theory with Friedmann–Robertson–Walker (FRW metrics. By the modification proposed in the cosmological equations subject to a perfect fluid we obtain new solutions interpreted as the Einstein static universe. It turns out that the non-vanishing size of initial scale factor of Einstein static universe depends on the non-vanishing three-dimensional spatial curvature of FRW metrics and also the graviton's mass. By dynamical system approach and numerical analysis, we find that the extracted solutions for closed and open universes can be stable for some viable ranges of equation of state parameter, viable values of fraction of two scale factors, and viable values of graviton's mass obeying the hierarchy m<

  5. Sulfur polymer cement, a new stabilization agent for mixed and low- level radioactive waste

    International Nuclear Information System (INIS)

    Darnell, G.R.

    1991-01-01

    Solidification and stabilization agents for radioactive, hazardous, and mixed wastes are failing to pass governmental tests at alarming rates. The Department of Energy's National Low-Level Waste Management Program funded testing of Sulfur Polymer Cement (SPC) by Brookhaven National Laboratory during the 1980s. Those tests and tests by the US Bureau of Mines (the original developer of SPC), universities, states, and the concrete industry have shown SPC to be superior to hydraulic cements in most cases. Superior in what wastes can be successfully combined and in the quantity of waste that can be combined and still pass the tests established by the US Environmental Protection Agency and the US Nuclear Regulatory Commission

  6. Mechanical stability of bentonite buffer system for high level nuclear waste

    International Nuclear Information System (INIS)

    Lempinen, A.

    1998-05-01

    According to present plans, high level nuclear waste in Finland is going to be disposed of in bedrock at a depth of several hundred metres. The spent fuel containers will be placed in boreholes drilled in the floors of deposition tunnels with engineered clay buffer, which is made of bentonite blocks. The tunnels will be filled with a mixture of bentonite and crushed rock. For stability calculations a thermomechanical model for compressed bentonite is needed. In the study a thermomechanically consistent model for reversible processes for swelling clays is presented. Preliminary calculations were performed and they show that uncertainty in material parameter values causes significantly different results. Therefore, measurements that are consistent with the model are needed

  7. The stability of candidate buffer materials for a low-level radioactive waste repository

    International Nuclear Information System (INIS)

    Torok, J.; Buckley, L.P.; Burton, G.R.; Tosello, N.B.; Maves, S.R.; Blimkie, M.E.; Donaldson, J.R.

    1989-11-01

    Inorganic ion-exchangers, clinoptilolite and clay, will be placed on the floor of a low-level radioactive waste repository to be built at Chalk River Nuclear Laboratories. The stability of these ion-exchange materials for a range of potential chemical environments in the repository was investigated. The leaching of waste forms and concrete and biological activity may create acidic or basic environment. The dissolution mechanisms of the ion exchangers for both acid and alkali conditions were established. Changes in distribution coefficients occurred shortly after the commencement of the treatment and were due to changes in the counter-ion content of the ion exchangers. No evidence was found to suggest gradual selective destruction of exchange sites responsible for the high distribution coefficients observed

  8. Theoretical justification of indicators system to estimate the regional stability level considering its development peculiarities

    Directory of Open Access Journals (Sweden)

    Granovska Lyudmyla Mykolayivna

    2016-02-01

    Full Text Available The article deals with theoretical analysis of the indicators system concept, observes in details such components of this system as society, nature, economy. The general indicators of social, ecological, and economic system development are considered. It has been found that indicators are the indexes system of ecological, economical, and social development and give the possibility to analyze and control the implementation of areas sustainable development statement. The system of indicators, which characterize the level of the region stability on the basis of domestic and foreign experience considering region peculiarities, has been improved. At that, the regional peculiarities of both the natural and resource potential and the economical activity impact on the natural and resource potential have been taken into account.

  9. Raney copper catalysts for the water-gas shift reaction: I. Preparation, activity and stability

    CSIR Research Space (South Africa)

    Mellor, JR

    1997-12-23

    Full Text Available precursor alloys, which, taken in required proportions were melted together, vigorously stirred and rapidly quenched in cold water. The alloy product, in the form of prills +50x5 mm were crushed using a Christie-Norris hammer mill and screened... variables has been undertaken. The continuous sponge-like Raney copper rim (i.e. leached region) suggested that the system may have unique stability characteristics. A co-precipitated and industrial cop- per-based WGS catalyst were tested under similar...

  10. Quality of Irrigation Water Affects Soil Functionality and Bacterial Community Stability in Response to Heat Disturbance.

    Science.gov (United States)

    Frenk, Sammy; Hadar, Yitzhak; Minz, Dror

    2018-02-15

    Anthropogenic activities alter the structure and function of a bacterial community. Furthermore, bacterial communities structured by the conditions the anthropogenic activities present may consequently reduce their stability in response to an unpredicted acute disturbance. The present mesocosm-scale study exposed soil bacterial communities to different irrigation water types, including freshwater, fertilized freshwater, treated wastewater, and artificial wastewater, and evaluated their response to a disturbance caused by heat. These effectors may be considered deterministic and stochastic forces common in agricultural operations of arid and semiarid regions. Bacterial communities under conditions of high mineral and organic carbon availability (artificial wastewater) differed from the native bacterial community and showed a proteobacterial dominance. These bacterial communities had a lower resistance to the heat treatment disturbance than soils under conditions of low resource availability (high-quality treated wastewater or freshwater). The latter soil bacterial communities showed a higher abundance of operational taxonomic units (OTUs) classified as Bacilli These results were elucidated by soil under conditions of high resource availability, which lost higher degrees of functional potential and had a greater bacterial community composition change. However, the functional resilience, after the disturbance ended, was higher under a condition of high resource availability despite the bacterial community composition shift and the decrease in species richness. The functional resilience was directly connected to the high growth rates of certain Bacteroidetes and proteobacterial groups. A high stability was found in samples that supported the coexistence of both resistant OTUs and fast-growing OTUs. IMPORTANCE This report presents the results of a study employing a hypothesis-based experimental approach to reveal the forces involved in determining the stability of a

  11. Emulsification technique affects oxidative stability of fish oil-in-water emulsion

    DEFF Research Database (Denmark)

    Horn, Anna Frisenfeldt; Nielsen, Nina Skall; Jensen, Louise Helene Søgaard

    .g. homogenization pressure can affect how proteins locate themselves at the interface of an emulsion. The hypothesis is therefore that emulsions produced with different emulsification equipments differ in their oxidative stability due to differences in the behaviour of the proteins at the interface. The aim...... of this study was therefore to compare lipid oxidation in 10% fish oil-in-water emulsions prepared by two different kinds of high pressure homogenizers i.e. a microfluidizer and a two valve high pressure homogenizer. Emulsions were made with equal droplet sizes, and with either 1% sodium caseinate or 1% whey...

  12. Emulsification technique affects oxidative stability of fish oil-in-water emulsions

    DEFF Research Database (Denmark)

    Horn, Anna Frisenfeldt; Nielsen, Nina Skall; Jensen, Louise Helene Søgaard

    .g. homogenization pressure can affect how proteins locate themselves at the interface of an emulsion. The hypothesis is therefore that emulsions produced with different emulsification equipments differ in their oxidative stability due to differences in the behaviour of the proteins at the interface. The aim...... of this study was to compare lipid oxidation in 10% fish oil-in-water emulsions prepared by two different kinds of high pressure homogenizers i.e. a microfluidizer and a two valve high pressure homogenizer. Emulsions were made with equal droplet sizes, and with either 1% sodium caseinate or 1% whey protein...

  13. Linear Polystyrene-Stabilized PdO Nanoparticle-Catalyzed Mizoroki-Heck Reactions in Water

    Directory of Open Access Journals (Sweden)

    Takuto Teratani

    2011-10-01

    Full Text Available Linear polystyrene-stabilized PdO nanoparticles (PS-PdONPs were prepared by thermal decomposition of Pd(OAc2 in the presence of polystyrene. X-ray diffraction (XRD and transmission electron microscopy (TEM indicated the production of PdO nanoparticles. The loading of palladium was determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES. PS-PdONPs exhibited high catalytic activity for Mizoroki-Heck reactions under air in water and could be recycled without loss of activity.

  14. Investigation of boiling water reactor stability and limit-cycle amplitude

    International Nuclear Information System (INIS)

    Damiano, B.; March-Leuba, J.A.; Euler, J.A.

    1991-01-01

    Galerkin's method has been applied to a boiling water reactor (BWR) dynamics model consisting of the point kinetics equations, which describe the neutronics, and a feedback transfer function, which describes the thermal hydraulics. The result is a low-order approximate solution describing BWR behavior during small-amplitude limit-cycle oscillations. The approximate solution has been used to obtain a stability condition, show that the average reactor power must increase during limit-cycle oscillations, and qualitatively determine how changes in transfer function values affect the limit-cycle amplitude. 6 refs., 2 figs., 2 tabs

  15. Interfacial transport phenomena and stability in liquid-metal/water systems: scaling considerations

    International Nuclear Information System (INIS)

    Abdulla, S.; Liu, X.; Anderson, M.; Bonazza, R.; Corradini, M.; Cho, D.

    2001-01-01

    One concept being considered for steam generation in innovative nuclear reactor applications, involves water coming into direct contact with a circulating molten metal. The vigorous agitation of the two fluids, the direct liquid-liquid contact and the consequent large interfacial area give rise to very high heat transfer coefficients and rapid steam generation. For an optimum design of such direct contact heat exchange and vaporization systems, detailed knowledge is necessary of the various flow regimes, interfacial transport phenomena, heat transfer and operational stability. In this paper we describe current results from the first year of this research that studies the transport phenomena involved with the injection of water into molten metals (e.g., lead alloys). In particular, this work discusses scaling considerations related to direct contact heat exchange, our experimental plans for investigation and a test plan for the important experimental parameters; i.e., the water and liquid metal mass flow rates, the liquid metal pool temperature and the ambient pressure of the direct contact heat exchanger. Past experimental work and initial scaling results suggest that our experiments can directly represent the proper liquid metal pool temperature and the water subcooling. The experimental variation in water and liquid metal flow rates and system pressure (1-10 bar), although smaller than the current conceptual system designs, is sufficient to verify the expected scale effects to demonstrate the phenomena. (authors)

  16. The effect of water on the stability of C60 fullerene nanowhiskers

    International Nuclear Information System (INIS)

    Miyazawa, Kun’ichi; Hotta, Kayoko

    2011-01-01

    The morphology of C 60 precipitates synthesized by using isopropyl alcohol (IPA) added with water was investigated in order to know the effect of water on the growth of C 60 nanowhiskers (C 60 NWs) in C 60 –toluene–IPA solution systems. The stability of C 60 NWs decreased and granular crystals of C 60 were formed in the solutions when IPA added with an excess amount of water was used in the liquid–liquid interfacial precipitation method. The C 60 NWs were found to be destabilized with time in the solutions added with water. The C 60 NWs dried in air showed similar Raman profiles irrespective of the use of IPA with and without water addition. The Raman profiles of granular C 60 single crystals showed the base lines much flatter than those of C 60 NWs, indicating that C 60 NWs possess a disordered crystal structure. By optimizing the growth condition, short C 60 NWs with aspect ratios ranging from 3 to 10 and an average length of about 1.8 μm were successfully fabricated. The short C 60 NWs are expected to be applicable for electrodes of organic thick film solar cells.

  17. The effect of different stabilizers on the thermostability of electron beam crosslinked polyethylene in hot water

    International Nuclear Information System (INIS)

    Hassanpour, S.; Khoylou, F.

    2003-01-01

    Plastic pipes owing to their flexibility, great lengths, easier handling and absence of corrosion have been used for hot-water installations. Crosslinked high-density polyethylene is one of the best materials, being used for this purpose. The useful lifetime of unstabilized polyethylene is predicted to vary from a few months in hot water (30-40 deg. C) to almost two years in cool water (0-10 deg. C). Polyethylene was mixed with different types of stabilizers, in order to increase its durability. The samples were irradiated at 100-150 kGy. The amount of gel fraction and the changes in mechanical properties were measured. Irradiated samples were immersed in hot water for 1000 h. The thermostability of the specimens and the existence of antioxidants were measured by the induction time technique using differential scanning calorimetry at different time intervals. Furthermore, the changes in chemical structure and mechanical properties of the samples during their immersion in hot water were determined

  18. Surface Water Connectivity, Flow Pathways and Water Level Fluctuation in a Cold Region Deltaic Ecosystem

    Science.gov (United States)

    Peters, D. L.; Niemann, O.; Skelly, R.; Monk, W. A.; Baird, D. J.

    2017-12-01

    The Peace-Athabasca Delta (PAD) is a 6000 km2 deltaic floodplain ecosystem of international importance (Wood Buffalo National Park, Ramsar Convention, UNESCO World Heritage, and SWOT satellite water level calibration/validation site). The low-relief floodplain formed at the confluence of the Peace, Athabasca and Birch rivers with Lake Athabasca. More than 1000 wetland and lake basins have varying degrees of connectivity to the main flow system. Hydroperiod and water storage is influenced by ice-jam and open-water inundations and prevailing semi-arid climate that control water drawdown. Prior studies have identified pathways of river-to-wetland floodwater connection and historical water level fluctuation/trends as a key knowledge gaps, limiting our knowledge of deltaic ecosystem status and potential hydroecological responses to climate change and upstream water alterations to flow contributions. To address this knowledge gap, surface elevation mapping of the PAD has been conducted since 2012 using aerial remote sensing Light Detection and Ranging (LiDAR), plus thousands of ground based surface and bathymetric survey points tied to Global Positioning System (GPS) were obtained. The elevation information was used to develop a high resolution digital terrain model to simulate and investigate surface water connectivity. Importantly, the surveyed areas contain a set of wetland monitoring sites where ground-based surface water connectivity, water level/depth, water quality, and aquatic ecology (eg, vegetation, macroinvertebrate and muskrat) have been examined. The goal of this presentation is to present an assessment of: i) surface water fluctuation and connectivity for PAD wetland sites; ii) 40+ year inter-annual hydroperiod reconstruction for a perched basin using a combination of field measurements, remote sensing estimates, and historical documents; and iii) outline an approach to integrate newly available hydro-bio-geophysical information into a novel, multi

  19. Stabilized Conservative Level Set Method with Adaptive Wavelet-based Mesh Refinement

    Science.gov (United States)

    Shervani-Tabar, Navid; Vasilyev, Oleg V.

    2016-11-01

    This paper addresses one of the main challenges of the conservative level set method, namely the ill-conditioned behavior of the normal vector away from the interface. An alternative formulation for reconstruction of the interface is proposed. Unlike the commonly used methods which rely on the unit normal vector, Stabilized Conservative Level Set (SCLS) uses a modified renormalization vector with diminishing magnitude away from the interface. With the new formulation, in the vicinity of the interface the reinitialization procedure utilizes compressive flux and diffusive terms only in the normal direction to the interface, thus, preserving the conservative level set properties, while away from the interfaces the directional diffusion mechanism automatically switches to homogeneous diffusion. The proposed formulation is robust and general. It is especially well suited for use with adaptive mesh refinement (AMR) approaches due to need for a finer resolution in the vicinity of the interface in comparison with the rest of the domain. All of the results were obtained using the Adaptive Wavelet Collocation Method, a general AMR-type method, which utilizes wavelet decomposition to adapt on steep gradients in the solution while retaining a predetermined order of accuracy.

  20. High-level radioactive waste from light-water reactors

    International Nuclear Information System (INIS)

    Cohen, B.L.

    1977-01-01

    The production of radioactive nuclei during the operation of a light-water reactor is traced, and their decay history is followed. The potential environmental impacts of this waste are calculated and shown to be comparable to those of other materials we produce. Assuming deep burial, it is shown that there are important time delays which prevent the waste from reaching the biosphere in the first few hundred years while its toxicity is decreasing by several orders of magnitude. In the long term,,the most important pathway to man was found to be through groundwater into food and water supplies, with consequences calculated t to be 0.4 fatalities in 10 6 years from each year of all-nuclear power in U.S. Other pathways considered and found to be less important include meteorites, volcanism, release through ground water to airborne particulate, and human intrusion by drilling and mining for unspecified materials and for salt. For time scales longer than 10 6 years, nuclear power is shown to reduce man's exposure to radiation by consuming uranium. A cost-benefit analysis is developed for surveillance of buried waste. It is shown that buried high-level waste is environmentally much less dangerous than uranium mill tailings

  1. Stability and forcing of the Iceland-Faroe inflow of water, heat, and salt to the Arctic

    Directory of Open Access Journals (Sweden)

    B. Hansen

    2010-12-01

    Full Text Available The flow of Atlantic water across the Greenland-Scotland Ridge (Atlantic inflow is critical for conditions in the Nordic Seas and Arctic Ocean by importing heat and salt. Here, we present a decade-long series of measurements from the Iceland-Faroe inflow branch (IF-inflow, which carries almost half the total Atlantic inflow. The observations show no significant trend in volume transport of Atlantic water, but temperature and salinity increased during the observational period. On shorter time scales, the observations show considerable variations but no statistically significant seasonal variation is observed and even weekly averaged transport values were consistently uni-directional from the Atlantic into the Nordic Seas. Combining transport time-series with sea level height from satellite altimetry and wind stress reveals that the force driving the IF-inflow across the topographic barrier of the Ridge is mainly generated by a pressure gradient that is due to a continuously maintained low sea level in the Southern Nordic Seas. This implies that the relative stability of the IF-inflow derives from the processes that lower the sea level by generating outflow from the Nordic Seas, especially the thermohaline processes that generate overflow. The IF-inflow is an important component of the system coupling the Arctic region to the North Atlantic through the thermohaline circulation, which has been predicted to weaken in the 21st century. Our observations show no indication of weakening.

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

    NARCIS (Netherlands)

    Sollie, S.

    2007-01-01

    Littoral zones with emergent vegetation are very narrow or even lacking in Dutch shallow lakes due to a combination of changed water level regime and unfavorable shore morphometry. These zones are important as a habitat for plants and animals, increasing species diversity. It has also been

  3. Improvement of Balance Stability in Older Individuals by On-Water Training.

    Science.gov (United States)

    Osti, Fabiana Rodrigues; de Souza, Caroline Ribeiro; Teixeira, Luis Augusto

    2018-03-09

    In the present investigation we evaluated the effect of stand-up paddle practice on upright postural control in older individuals. Participants were assigned to a group practicing stand-up paddle on seawater or to a walking control group. Balance stability was evaluated in the tandem Romberg and tiptoes postures, comparing the conditions of eyes open versus closed. Results showed that stand-up paddle practice led to reduced anteroposterior and mediolateral amplitudes of body sway in both visual conditions, while walking led to no effect on balance. These results suggest that the challenge of keeping body balance on an unstable board during on-water stand-up paddle practice is transferred to postural tasks performed on a stable support surface, with generalization to sensory and biomechanical conditions different from those experienced during the training. Our results suggest that on-water balance training could be considered as a potential procedure to improve balance control in older adults.

  4. Digitalizing historical high resolution water level data: Challenges and opportunities

    Science.gov (United States)

    Holinde, Lars; Hein, Hartmut; Barjenbruch, Ulrich

    2017-04-01

    Historical tide-gauge data offer the opportunities for determining variations in key characteristics for water level data and the analyses of past extreme events (storm surges). These information are important for calculating future trends and scenarios. But there are challenges involved due to the extensive effort needed to digitalize gauge sheets and quality control the resulting historical data. Based on these conditions, two main sources for inaccuracies in historical time series can be identified. First are several challenges due to the digitalization of the historical data, e.g. general quality of the sheets, multiple crossing lines of the observed water levels and additional comments on the sheet describing problems or additional information during the measurements. Second are problems during the measurements themselves. These can include the incorrect positioning of the sheets, trouble with the tide-gauge and maintenance. Errors resulting from these problems can be e.g. flat lines, discontinuities and outlier. Especially, the characterization of outliers has to be conducted carefully, to distinguish between real outliers and the appearance of extreme events. Methods for the quality control process involve the use of statistics, machine learning and neural networks. These will be described and applied to three different time series from tide gauge stations at the cost of Lower Saxony, Germany. Resulting difficulties and outcomes of the quality control process will be presented and explained. Furthermore, we will present a first glance at analyses for these time series.

  5. A survey on levels and seasonal changes of assimilable organic carbon (AOC) and its precursors in drinking water.

    Science.gov (United States)

    Ohkouchi, Yumiko; Ly, Bich Thuy; Ishikawa, Suguru; Aoki, Yusuke; Echigo, Shinya; Itoh, Sadahiko

    2011-10-01

    In Japan, customers' concerns about chlorinous odour in drinking water have been increasing. One promising approach for reducing chlorinous odour is the minimization of residual chlorine in water distribution, which requires stricter control of organics to maintain biological stability in water supply systems. In this investigation, the levels and seasonal changes of assimilable organic carbon (AOC) and its precursors in drinking water were surveyed to accumulate information on organics in terms of biological stability. In tap water samples purified through rapid sand filtration processes, the average AOC concentration was 174 microgC/L in winter and 60 microgC/L in summer. This difference seemed to reflect the seasonal changes of AOC in the natural aquatic environment. On the other hand, very little or no AOC could be removed after use of an ozonation-biological activated carbon (BAC) process. Especially in winter, waterworks should pay attention to BAC operating conditions to improve AOC removal. The storage of BAC effluent with residual chlorine at 0.05-0.15 mgCl2/L increased AOC drastically. This result indicated the possibility that abundant AOC precursors remaining in the finished water could contribute to newly AOC formation during water distribution with minimized residual chlorine. Combined amino acids, which remained at roughly equivalent to AOC in finished water, were identified as major AOC precursors. Prior to minimization of residual chlorine, enhancement of the removal abilities for both AOC and its precursors would be necessary.

  6. Stability and Degradation Mechanisms of Radiation-Grafted Polymer Electrolyte Membranes for Water Electrolysis.

    Science.gov (United States)

    Albert, Albert; Lochner, Tim; Schmidt, Thomas J; Gubler, L

    2016-06-22

    Radiation-grafted membranes are a promising alternative to commercial membranes for water electrolyzers, since they exhibit lower hydrogen crossover and area resistance, better mechanical properties, and are of potentially lower cost than perfluoroalkylsulfonic acid membranes, such as Nafion. Stability is an important factor in view of the expected lifetime of 40 000 h or more of an electrolyzer. In this study, combinations of styrene (St), α-methylstyrene (AMS), acrylonitrile (AN), and 1,3-diisopropenylbenzene (DiPB) are cografted into 50 μm preirradiated poly(ethylene-co-tetrafluoroethylene) (ETFE) base film, followed by sulfonation to produce radiation-grafted membranes. The stability of the membranes with different monomer combinations is compared under an accelerated stress test (AST), and the degradation mechanisms are investigated. To mimic the conditions in an electrolyzer, in which the membrane is always in contact with liquid water at elevated temperature, the membranes are immersed in water for 5 days at 90 °C, so-called thermal stress test (TST). In addition to testing in air atmosphere tests are also carried out under argon to investigate the effect of the absence of oxygen. The water is analyzed with UV-vis spectroscopy and ion chromatography. The ion exchange capacity (IEC), swelling degree, and Fourier transform infrared (FTIR) spectra of the membranes are compared before and after the test. Furthermore, energy-dispersive X-ray (EDX) spectroscopic analysis of the membrane cross-section is performed. Finally, the influence of the TST to the membrane area resistance and hydrogen crossover is measured. The stability increases along the sequence St/AN, St/AN/DiPB, AMS/AN, and AMS/AN/DiPB grafted membrane. The degradation at the weak-link, oxygen-induced degradation, and hydrothermal degradation are proposed in addition to the "swelling-induced detachment" reported in the literature. By mitigating the possible paths of degradation, the AMS

  7. Mercury and water level fluctuations in lakes of northern Minnesota

    Science.gov (United States)

    Larson, James H.; Maki, Ryan P; Christensen, Victoria G.; Sandheinrich, Mark B.; LeDuc, Jaime F.; Kissane, Claire; Knights, Brent C.

    2017-01-01

    Large lake ecosystems support a variety of ecosystem services in surrounding communities, including recreational and commercial fishing. However, many northern temperate fisheries are contaminated by mercury. Annual variation in mercury accumulation in fish has previously been linked to water level (WL) fluctuations, opening the possibility of regulating water levels in a manner that minimizes or reduces mercury contamination in fisheries. Here, we compiled a long-term dataset (1997-2015) of mercury content in young-of-year Yellow Perch (Perca flavescens) from six lakes on the border between the U.S. and Canada and examined whether mercury content appeared to be related to several metrics of WL fluctuation (e.g., spring WL rise, annual maximum WL, and year-to-year change in maximum WL). Using simple correlation analysis, several WL metrics appear to be strongly correlated to Yellow Perch mercury content, although the strength of these correlations varies by lake. We also used many WL metrics, water quality measurements, temperature and annual deposition data to build predictive models using partial least squared regression (PLSR) analysis for each lake. These PLSR models showed some variation among lakes, but also supported strong associations between WL fluctuations and annual variation in Yellow Perch mercury content. The study lakes underwent a modest change in WL management in 2000, when winter WL minimums were increased by about 1 m in five of the six study lakes. Using the PLSR models, we estimated how this change in WL management would have affected Yellow Perch mercury content. For four of the study lakes, the change in WL management that occurred in 2000 likely reduced Yellow Perch mercury content, relative to the previous WL management regime.

  8. T-mixer operating with water at different temperatures: Simulation and stability analysis

    Science.gov (United States)

    Siconolfi, L.; Camarri, S.; Salvetti, M. V.

    2018-03-01

    In this paper we investigate the transition from the vortex to the engulfment regime in a T-mixer when the two entering flows have different viscosity. In particular we consider as working fluid water entering the two inlet channels of the mixer at two different temperatures. Contrary to the isothermal case, at low Reynolds numbers the vortex regime shows only a single reflectional symmetry, due to the nonhomogeneous distribution of the viscosity. Increasing the Reynolds number, a symmetry-breaking bifurcation drives the system to a new steady flow configuration, usually called the engulfment regime, similar to what it is possible to observe in an isothermal case. This flow regime is associated with an increase of the mixing between the two inlet streams. It is shown by direct numerical simulation (DNS) and by stability analysis that the engulfment regime is promoted by the temperature difference. Starting from the DNSs, the resulting flow fields are analyzed in detail considering different temperature jumps between the two inlet boundaries. Furthermore, dedicated linear stability analyses are carried out to investigate the instability mechanism associated with the occurrence of the engulfment regime. In particular, similarly to the case without temperature differences, the onset of engulfment is driven by the momentum equation, and the temperature field does not lead to any additional instability mechanism. However, the existence of a temperature field leads to quantitative changes of the stability characteristics and of the resulting flow fields via a variation of the viscosity coefficient.

  9. Cyclodextrin-grafted barium titanate nanoparticles for improved dispersion and stabilization in water-based systems

    Science.gov (United States)

    Serra-Gómez, R.; Martinez-Tarifa, J. M.; González-Benito, J.; González-Gaitano, G.

    2016-01-01

    Ceramic nanoparticles with piezoelectric properties, such as BaTiO3 (BT), constitute a promising approach in the fields of nanocomposite materials and biomaterials. In the latter case, to be successful in their preparation, the drawback of their fast aggregation and practically null stability in water has to be overcome. The objective of this investigation has been the surface functionalization of BaTiO3 nanoparticles with cyclodextrins (CDs) as a way to break the aggregation and improve the stability of the nanoparticles in water solution, preventing and minimizing their fast precipitation. As a secondary goal, we have achieved extra-functionality of the nanoparticles, bestowed from the hydrophobic cavity of the macrocycle, which is able to lodge guest molecules that can form inclusion complexes with the oligosaccharide. The nanoparticle functionalization has been fully tracked and characterized, and the cytotoxicity of the modified nanoparticles with fibroblasts and pre-osteoblasts cell lines has been assessed with excellent results in a wide range of concentrations. The modified nanoparticles were found to be suitable for the easy preparation of nanocomposite hydrogels, via dispersion in hydrophilic polymers of typical use in biomedical applications (PEG, Pluronics, and PEO), and further processed in the form of films via water casting, showing very good results in terms of homogeneity in the dispersion of the filler. Likewise, as examples of application and with the aim of exploring a different range of nanocomposites, rhodamine B was included in the macrocycles as a model molecule, and films prepared from a thermoplastic matrix (EVA) via high-energy ball milling have been tested by impedance spectroscopy to discuss their dielectric properties, which indicated that even small modifications in the surface of the nanoparticles generate a different kind of interaction with the polymeric matrix. The CD-modified nanoparticles are thus suitable for easy preparation

  10. Cyclodextrin-grafted barium titanate nanoparticles for improved dispersion and stabilization in water-based systems

    Energy Technology Data Exchange (ETDEWEB)

    Serra-Gómez, R. [Universidad de Navarra, Departamento de Química y Edafología (Spain); Martinez-Tarifa, J. M. [Universidad Carlos III de Madrid, Departamento de Ingeniería Eléctrica (Spain); González-Benito, J. [Universidad Carlos III de Madrid, Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química, IQMAAB (Spain); González-Gaitano, G., E-mail: gaitano@unav.es [Universidad de Navarra, Departamento de Química y Edafología (Spain)

    2016-01-15

    Ceramic nanoparticles with piezoelectric properties, such as BaTiO{sub 3} (BT), constitute a promising approach in the fields of nanocomposite materials and biomaterials. In the latter case, to be successful in their preparation, the drawback of their fast aggregation and practically null stability in water has to be overcome. The objective of this investigation has been the surface functionalization of BaTiO{sub 3} nanoparticles with cyclodextrins (CDs) as a way to break the aggregation and improve the stability of the nanoparticles in water solution, preventing and minimizing their fast precipitation. As a secondary goal, we have achieved extra-functionality of the nanoparticles, bestowed from the hydrophobic cavity of the macrocycle, which is able to lodge guest molecules that can form inclusion complexes with the oligosaccharide. The nanoparticle functionalization has been fully tracked and characterized, and the cytotoxicity of the modified nanoparticles with fibroblasts and pre-osteoblasts cell lines has been assessed with excellent results in a wide range of concentrations. The modified nanoparticles were found to be suitable for the easy preparation of nanocomposite hydrogels, via dispersion in hydrophilic polymers of typical use in biomedical applications (PEG, Pluronics, and PEO), and further processed in the form of films via water casting, showing very good results in terms of homogeneity in the dispersion of the filler. Likewise, as examples of application and with the aim of exploring a different range of nanocomposites, rhodamine B was included in the macrocycles as a model molecule, and films prepared from a thermoplastic matrix (EVA) via high-energy ball milling have been tested by impedance spectroscopy to discuss their dielectric properties, which indicated that even small modifications in the surface of the nanoparticles generate a different kind of interaction with the polymeric matrix. The CD-modified nanoparticles are thus suitable for easy

  11. The effect of cure conditions on the stability of cement waste forms after immersion in water

    International Nuclear Information System (INIS)

    Siskind, B.; Adams, J.W.; Clinton, J.H.; Piciulo, P.L.; McDaniel, K.

    1988-01-01

    We investigated the effects of curing conditions on the stability of cement-solidified ion-exchange resins after immersion in water. The test specimens consisted of partially depleted mixed-bed bead resins solidified in one of three vendor-supplied Portland I cement formulations, in a reference cement formulation, or in a gypsum-based binder formulation. We cured samples prepared using each formulation in sealed containers for periods of 7, 14, or 28 days as well as in air or with an accelerated heat cure prior to 90-day immersion in water. Two cement formulations exhibited apparent Portland-cement-like behavior, i.e., compressive strength increased or stabilized with increasing cure time. Two cement formulations exhibited behavior apparently unlike that of Portland cement, i.e., compressive strength decreased with increasing cure time. Such non-Portland-cement-like behavior is correlated with higher waste loadings. The gypsum-based formulation exhibited approximately constant compressive strength with cure time. Accelerated heat cures may not give compressive strengths representative of real-time cures. Some physical deterioration (cracking, spalling) of the waste form occurs during immersion

  12. The effect of cure conditions on the stability of cement waste forms after immersion in water

    International Nuclear Information System (INIS)

    Siskind, B.; Adams, J.W.; Clinton, J.H.; Piciulo, P.L.

    1988-01-01

    The authors investigated the effects of curing conditions on the stability of cement-solidified ion-exchange resins after immersion in water. The test specimens consisted of partially depleted mixed-bed bead resins solidified in one of three vendor-supplied Portland I cement formulations, in a reference cement formulation, or in a gypsum-based binder formulation. They cured samples prepared using each formulation in sealed containers for periods of 7, 14, or 28 days as well as in air or with an accelerated heat cure prior to 90-day immersion in water. Two cement formulations exhibited apparent Portland-cement-like behavior, i.e., compressive strength increased or stabilized with increasing cure time. Two cement formulations exhibited behavior apparently unlike that of Portland cement, i.e. compressive strength decreased with increasing cure time. Such non-Portland-cement-like behavior is correlated with higher waste loadings. The gypsum-based formulation exhibited approximately constant compressive strength with cure time. Accelerated heat cures may not give compressive strengths representative of real-time cures. Some physical deterioration (cracking, spalling) of the waste form occurs during immersion

  13. Level of Faecal Coliform Contamination of Drinking Water Sources ...

    African Journals Online (AJOL)

    2018-03-01

    Mar 1, 2018 ... CONCLUSION: In this study, the prevalence of positive faecal coliform at water source was high. Educational status, sanitary. Risk of contamination at the water source, water shortage experience had significant associations with the presence of faecal coliform in drinking water sources. KEYWORDS: Water ...

  14. Increasing stability of water-soluble PQQ glucose dehydrogenase by increasing hydrophobic interaction at dimeric interface

    Directory of Open Access Journals (Sweden)

    Ferri Stefano

    2005-02-01

    Full Text Available Abstract Background Water-soluble quinoprotein glucose dehydrogenase (PQQGDH-B from Acinetobacter calcoaceticus has a great potential for application as a glucose sensor constituent. Because this enzyme shows no activity in its monomeric form, correct quaternary structure is essential for the formation of active enzyme. We have previously reported on the increasing of the stability of PQQGDH-B by preventing the subunit dissociation. Previous studies were based on decreasing the entropy of quaternary structure dissociation but not on increasing the interaction between the two subunits. We therefore attempted to introduce a hydrophobic interaction in the dimeric interface to increase the stability of PQQGDH-B. Results Amino acid residues Asn340 and Tyr418 face each other at the dimer interface of PQQGDH-B, however no interaction exists between their side chains. We simultaneously substituted Asn340 to Phe and Tyr418 to Phe or Ile, to create the two mutants Asn340Phe/Tyr418Phe and Asn340Phe/Tyr418Ile. Furthermore, residues Leu280, Val282 and Val342 form a hydrophobic region that faces, on the other subunit, residues Thr416 and Thr417, again without any specific interaction. We simultaneously substituted Thr416 and Thr417 to Val, to create the mutant Thr416Val/Thr417Val. The temperatures resulting in lose of half of the initial activity of the constructed mutants were increased by 3–4°C higher over wild type. All mutants showed 2-fold higher thermal stability at 55°C than the wild-type enzyme, without decreasing their catalytic activities. From the 3D models of all the mutant enzymes, the predicted binding energies were found to be significantly greater that in the wild-type enzyme, consistent with the increases in thermal stabilities. Conclusions We have achieved via site-directed mutagenesis the improvement of the thermal stability of PQQGDH-B by increasing the dimer interface interaction. Through rational design based on the quaternary

  15. Does Semi-Rigid Instrumentation Using Both Flexion and Extension Dampening Spacers Truly Provide an Intermediate Level of Stabilization?

    Directory of Open Access Journals (Sweden)

    Dilip Sengupta

    2013-01-01

    Full Text Available Conventional posterior dynamic stabilization devices demonstrated a tendency towards highly rigid stabilization approximating that of titanium rods in flexion. In extension, they excessively offload the index segment, making the device as the sole load-bearing structure, with concerns of device failure. The goal of this study was to compare the kinematics and intradiscal pressure of monosegmental stabilization utilizing a new device that incorporates both a flexion and extension dampening spacer to that of rigid internal fixation and a conventional posterior dynamic stabilization device. The hypothesis was the new device would minimize the overloading of adjacent levels compared to rigid and conventional devices which can only bend but not stretch. The biomechanics were compared following injury in a human cadaveric lumbosacral spine under simulated physiological loading conditions. The stabilization with the new posterior dynamic stabilization device significantly reduced motion uniformly in all loading directions, but less so than rigid fixation. The evaluation of adjacent level motion and pressure showed some benefit of the new device when compared to rigid fixation. Posterior dynamic stabilization designs which both bend and stretch showed improved kinematic and load-sharing properties when compared to rigid fixation and when indirectly compared to existing conventional devices without a bumper.

  16. Long term OSLD reader stability in the ACDS level one audit

    International Nuclear Information System (INIS)

    Alves, Andrew D.C.; Lye, Jessica; Kenny, John; Dunn, Leon; Lehmann, Joerg; Cole, Andrew; Williams, Ivan; Kron, Tomas; Butler, Duncan; Johnston, Peter

    2015-01-01

    The Australian Clinical Dosimetry Service (ACDS) has demonstrated the capacity to perform a basic dosimetry audit on all radiotherapy clinics across Australia. During the ACDS’s three and a half year trial the majority of the audits were performed using optically stimulated luminescence dosimeters (OSLD) mailed to facilities for exposure to a reference dose, and then returned to the ACDS for analysis. This technical note investigates the stability of the readout process under the large workload of the national dosimetry audit. The OSLD readout uncertainty contributes to the uncertainty of several terms of the dose calculation equation and is a major source of uncertainty in the audit. The standard deviation of four OSLD readouts was initially established at 0.6 %. Measurements over 13 audit batches—each batch containing 200−400 OSLDs—showed variability (0.5−0.9 %) in the readout standard deviation. These shifts have not yet necessitated a change to the audit scoring levels. However, a standard deviation in OSLD readouts greater than 0.9 % will change the audit scoring levels. We identified mechanical wear on the OSLD readout adapter as a cause of variability in readout uncertainty, however, we cannot rule out other causes. Additionally we observed large fluctuations in the distribution of element correction factors (ECF) for OSLD batches. We conclude that the variability in the width of the ECF distribution from one batch to another is not caused by variability in readout uncertainty, but rather by variations in the OSLD stock.

  17. Energetics and stability of azulene: From experimental thermochemistry to high-level quantum chemical calculations

    International Nuclear Information System (INIS)

    Sousa, Clara C.S.; Matos, M. Agostinha R.; Morais, Victor M.F.

    2014-01-01

    Highlights: • Experimental standard molar enthalpy of formation, sublimation azulene. • Mini-bomb combustion calorimetry, sublimation Calvet microcalorimetry. • High level composite ab initio calculations. • Computational estimate of the enthalpy of formation of azulene. • Discussion of stability and aromaticity of azulene. - Abstract: The standard (p 0 = 0.1 MPa) molar enthalpy of formation for crystalline azulene was derived from the standard molar enthalpy of combustion, in oxygen, at T = 298.15 K, measured in a mini-bomb combustion calorimeter (aneroid isoperibol calorimeter) and the standard molar enthalpy of sublimation, at T = 298.15 K, measured by Calvet microcalorimetry. From these experiments, the standard molar enthalpy of formation of azulene in the gaseous phase at T = 298.15 K was calculated. In addition, very accurate quantum chemical calculations at the G3 and G4 composite levels of calculation were conducted in order to corroborate our experimental findings and further clarify and establish the definitive standard enthalpy of formation of this interesting non-benzenoid hydrocarbon

  18. Physical modeling of stabilization water processes of reverse cooling system the thermal power plant

    Science.gov (United States)

    Vlasov, S. M.; Chichirov, A. A.; Chichirova, N. D.; Filimonova, A. A.; Vinogradov, A. S.

    2017-11-01

    The system of reverse cooling is an integral part of combined heat and power plant and, respectively, demands constant control and regulation of structure and the number of deposits from circulating water for maintenance of the steady mode of equipment. Insufficient circulating water processing turns into a big internal problem for combined heat and power plant work and is a source of heat exchange, surfaces pollution sludge formation in device channels, equipment corrosion, biological fouling, biosludge formation, etc. Depending on the reverse cooling functioning at combined heat and power plant various problems demanding accurately differentiated approach to the decision are identified. Various criteria allowing to define existence and intensity of deposits and ways of fight against the formed deposits and equipment corrosion are offered. For each type of reverse cooling system the possible reasons of deposits formation on the heatpower equipment are analyzed and physical and chemical methods for circulating water stabilization are described. These methods safe water treatment installation modes in a case of the interfaced reverse cooling system and provide the minimum quantity of drains in a case with not interfaced system.

  19. Water-in-diesel fuel nanoemulsions: Preparation, stability and physical properties

    Directory of Open Access Journals (Sweden)

    M.R. Noor El-Din

    2013-12-01

    Full Text Available In this work, water-in-diesel fuel nanoemulsions were prepared with mixed nonionic surfactants. Several mixtures of sorbitan monooleate and polyoxyethylene (20 sorbitan monooleate, with different Hydrophilic–Lipophilic Balance (HLB values (9.6, 9.8, 10, 10.2 and 10.4 were prepared to achieve the optimal HLB value. Three mixed surfactant concentrations were prepared at 6%, 8% and 10% to identify the optimum concentration. Five emulsions with different water contents: 5%, 6%, 7%, 8% and 9% (wt./wt. were prepared using high energy method at the optimum conditions (HLB = 10 and mixed surfactant concentration = 10%. The effect of HLB value, mixed surfactant concentration and water content on the droplet size has been studied. The interfacial tension and thermodynamic properties of the individual and the blended emulsifiers were investigated. Droplet size of the prepared nanoemulsions was determined by dynamic light scattering and the nanoemulsion stability was assessed by measuring the variation of the droplet size as a function of time. From the obtained results, it was found that the mean droplet sizes were formed between 49.55 and 104.4 nm depending on HLB value, surfactant concentration and water content of the blended emulsifiers. The physical properties, kinematic viscosity and density, of the prepared nanoemulsions and the effect of different temperatures on these properties were measured.

  20. Role of water repellency in aggregate stability of cultivated soils under simulated raindrop impact

    Science.gov (United States)

    Kořenková, Lucia; Matúš, Peter

    2015-07-01

    Soil aggregate stability (AS) is an important indicator of soil physical quality. For the purpose of this research it was hypothesized that particular properties such as water repellency (WR) influence soil aggregation and AS. Directly after sampling, WR was detected for three soils, after a week of air-drying two of these soils still showed some resistance to penetration by a water drop placed on the surface (WDPT test). The study examines AS of air-dried texturally different aggregates of size 0.25-0.5 mm taken from surface layers (5-15 cm depth) of six agriculturally used soils. The procedure involves exposure of soil aggregates to direct impact of water drops. Results showed that soil AS increases in order: cutanic Luvisol (siltic) Chernozem < calcic mollic Fluvisol < mollic grumic Vertisol (pellic) < mollic Fluvisol (calcaric) < gleyic Fluvisol (eutric). Gradual increase in AS can be explained by the increase in soil organic matter content and its hydrophobic properties. Although WR has been most commonly observed in soils under forests and grass cover, the results confirmed that cultivated soils may also create water-stable aggregates, especially in the case when their organic matter induces WR under particular moisture conditions.

  1. Assessing water pollution level and gray water footprint of anthropogenic nitrogen in agricultural system

    Science.gov (United States)

    Huang, Guorui; Chen, Han; Yu, Chaoqing

    2017-04-01

    Water pollution has become a global problem which is one of the most critical issues of today's water treatment. At a spatial resolution of 10km, we use the DeNitrification-DeComposition (DNDC) model to simulate the biogeochemical processes for major cropping systems from 1955 to 2014, estimate the anthropogenic nitrogen loads to fresh, and calculate the resultant grey water footprints and N-related water pollution level in China. The accumulated annual Nitrogen loads to fresh from agricultural system is 0.38Tg in 1955 and 4.42Tg in 2014, while the grey water footprints vary from 1.53 billion m3 to 17.67 billion m3, respectively. N loads in north of China contributes much more on the N leaching because of the high fertilizer but in south of China, it is mainly focused on the N runoff because of the heavy rain. There are more than 25% of grids with WPL>1 (exceed the water capacity of assimilation), which is mainly located on the North China Plain.

  2. Stability of water clusters on hydronium ions formed under the conditions of radioactive contamination of the atmosphere

    International Nuclear Information System (INIS)

    Shevkunov, S.V.

    1998-01-01

    The hydronium ion hydrate shell H 3 O + , formed by addition of water molecule to proton is studied with the purpose of explaining the experimentally observed noticeable accumulation of ions by the atmosphere radioactive contamination. The results of computerized simulation of water clusters on hydronium ions testify to the clearly expressed stabilizing role of the proton electrical field

  3. Removal of Natural Organic Matter Fractions by Anion Exchange : Impact on drinking water treatment processes and biological stability

    NARCIS (Netherlands)

    Grefte, A.

    2013-01-01

    This researched focused on improving drinking water quality, specifically the biological stability of the produced drinking water. Natural organic matter (NOM) can be a source of nutrients for bacteria present in the distribution system, which can cause regrowth. Specifically, small organic acids

  4. Sensitive detection of mercury (II) ion using water-soluble captopril-stabilized fluorescent gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Jiu-Ju; Huang, Hong; Chen, Wei-Jie; Chen, Jian-Rong; Lin, Hong-Jun; Wang, Ai-Jun, E-mail: ajwang@zjnu.cn

    2013-07-01

    In our work, a simple, facile, and green method was developed for the synthesis of water-soluble and well-dispersed fluorescent gold nanoparticles (Au NPs) within 5 min, using captopril as a capping agent. The as-prepared Au NPs showed strong emission at 414 nm, with a quantum yield of 5.5%. The fluorescence of the Au NPs can be strongly quenched by mercury (II) ion (Hg{sup 2+}) due to the stronger interactions between thiolates (RS{sup −}) and Hg{sup 2+}. It was applied to the detection of Hg{sup 2+} in water samples in the linear ranges of 0.033–0.133 μM and 0.167–2.500 μM, with a detection limit of 0.017 μM. Therefore, the as-prepared Au NPs can meet the requirement for monitoring Hg{sup 2+} in environmental samples. - Graphical abstract: In this work, we developed a simple, fast and facile method for the preparation of water-soluble and fluorescent gold nanoparticles (Au NPs). The trace existence of Hg{sup 2+} could strongly quench the fluorescence of the Au NPs. The Au NPs were used to detect highly toxic Hg{sup 2+} in water samples with high sensitivity and selectivity. Highlights: ► Water-soluble fluorescent Au NPs stabilized by captopril ► The synthesis procedure was simple, fast and facile. ► The fluorescence of the Au NPs can be strongly quenched by Hg{sup 2+}. ► The Au NPs were used to the assay of Hg{sup 2+} in water samples with high sensitivity and selectivity.

  5. Comparison of ground reaction forces during the Basic Step on the Core Board platform at various levels of stability.

    Science.gov (United States)

    Karczewska, Magdalena; Madej, Anna; Sadowska, Aleksandra; Mastalerz, Andrzej; Urbanik, Czesław

    2016-01-01

    The aim of this paper was to examine and compare the changes of ground reaction forces observed during the Basic Step on the Core Board fitness device at various levels of stability. The study involved 10 female students. Participants stepped on and off the Core Board 10 times at 3 levels of stability. After completing a series of steps, the Core Board's stability was modified and the participant repeated the whole series. The measurement platform to examine three components of the reaction force (horizontal in the sagittal and frontal planes, and vertical) was used. The ground reaction force (GRF) observed on the Core Board, in the vertical and horizontal components is higher at all three levels of stability than on the platform without the device. Significant differences in GRF were observed in the horizontal component in the frontal plane (Fz) at all three levels of mobility as well as in impulse, measured on platforms with the device. The results on the Core Board training device present highest horizontal ground reaction forces in frontal plane at the highest level of Core Board mobility and this showing little medio-lateral stability and a more reactive way of movement regulation of the participants. As a consequence of the force patterns found it may be suggested that fitness training concepts should focus more possibly higher strains on the locomotor system most likely caused by changed ground reaction force patterns, an idea that has to be further analyzed with more complex measurement approaches.

  6. Global Anthropogenic Phosphorus Loads to Fresh Water, Grey Water Footprint and Water Pollution Levels: A High-Resolution Global Study

    Science.gov (United States)

    Mekonnen, M. M.; Hoekstra, A. Y. Y.

    2014-12-01

    We estimated anthropogenic phosphorus (P) loads to freshwater, globally at a spatial resolution level of 5 by 5 arc minute. The global anthropogenic P load to freshwater systems from both diffuse and point sources in the period 2002-2010 was 1.5 million tonnes per year. China contributed about 30% to this global anthropogenic P load. India was the second largest contributor (8%), followed by the USA (7%), Spain and Brazil each contributing 6% to the total. The domestic sector contributed the largest share (54%) to this total followed by agriculture (38%) and industry (8%). Among the crops, production of cereals had the largest contribution to the P loads (32%), followed by fruits, vegetables, and oil crops, each contributing about 15% to the total. We also calculated the resultant grey water footprints, and relate the grey water footprints per river basin to runoff to calculate the P-related water pollution level (WPL) per catchment.

  7. Emergency action levels for light water reactors. Draft report

    International Nuclear Information System (INIS)

    1981-10-01

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

  8. Level Recession Of Emissions Release By Motor-And-Tractor Diesel Engines Through The Application Of Water-Fuel Emulsions

    Science.gov (United States)

    Ivanov, A.; Chikishev, E.

    2017-01-01

    The paper is dedicated to a problem of environmental pollution by emissions of hazardous substances with the exhaust gases of internal combustion engines. It is found that application of water-fuel emulsions yields the best results in diesels where production of a qualitative carburetion is the main problem for the organization of working process. During pilot studies the composition of a water-fuel emulsion with the patent held is developed. The developed composition of a water-fuel emulsion provides its stability within 14-18 months depending on mass content of components in it while stability of emulsions’ analogues makes 8-12 months. The mode of operation of pilot unit is described. Methodology and results of pilot study of operation of diesel engine on a water-fuel emulsion are presented. Cutting time of droplet combustion of a water-fuel emulsion improves combustion efficiency and reduces carbon deposition (varnish) on working surfaces. Partial dismantling of the engine after its operating time during 60 engine hours has shown that there is a removal of a carbon deposition in cylinder-piston group which can be observed visually. It is found that for steady operation of the diesel and ensuring decrease in level of emission of hazardous substances the water-fuel emulsion with water concentration of 18-20% is optimal.

  9. Stabilization of low-level mixed waste in chemically bonded phosphate ceramics

    International Nuclear Information System (INIS)

    Wagh, A.S.; Singh, D.; Sarkar, A.V.

    1994-06-01

    Mixed waste streams, which contain both chemical and radioactive wastes, are one of the important categories of DOE waste streams needing stabilization for final disposal. Recent studies have shown that chemically bonded phosphate ceramics may have the potential for stabilizing these waste streams, particularly those containing volatiles and pyrophorics. Such waste streams cannot be stabilized by conventional thermal treatment methods such as vitrification. Phosphate ceramics may be fabricated at room temperature into durable, hard and dense materials. For this reason room-temperature-setting phosphate ceramic waste forms are being developed to stabilize these to ''problem waste streams.''

  10. The Effect of Different Perturbations on the Stability Analysis of Light Water Reactors

    International Nuclear Information System (INIS)

    Dykin, Victor

    2010-09-01

    Neutron noise analysis techniques are studied and developed, with primary use of determining the stability of Boiling Water Reactors (BWRs). In particular, the role of a specific perturbation prevailing in Light Water Reactors, the propagating density perturbation, in the stability of BWRs and on the noise field of LWRs in general, is investigated by considering three topics. In the first topics, we investigate how the neutronic response of the reactor, usually described as a second order system driven by a white noise driving force, is affected by a non-white driving force. This latter arises from the reactivity effect of the propagating density perturbations. The investigation is performed by using spectral and correlation analysis. Propagating perturbations with different velocities are analyzed. We investigate how the accuracy of the determination of the so-called decay ratio (DR) of the system, based on the assumption of white noise driving force, deteriorates with deviations from the white noise character of the driving force. In the second topics, the space dependence of the neutron noise, induced by propagating density perturbations, represented through the perturbation of the absorption, is determined and discussed. A full analytical solution was obtained by the use of the Green's function technique. The solution was analyzed for different frequencies and different system sizes. An interesting new interference effect between the point-kinetic and space-dependent components of the induced noise was discovered and interpreted in physical terms. In the last topics, a non-linear stability analysis of a BWR is performed, using so called Reduced Order Model (ROM) techniques. A ROM is usually constructed by reducing the full set of 3D space-time dependent neutron-kinetics, thermal-hydraulics and heat transfer equations to time-dependent ones, by considering space dependence in a lumped parameter model (one or two discrete channels). The main novelty of our work

  11. Investigation of the Relationship among Rainfall, Unsaturated Water Pressure and Ground Water Level Using Grey System Theory

    Science.gov (United States)

    Yu, C.; Cheng, C.; Ke, T.; Wen, J.

    2008-12-01

    Rainfall is infiltrated through the surface into the vadose zone and induces the variation of the ground water level. However, the hydrological system of the rainfall infiltration is complex. How to establish the relationship between the rainfall and variation of the ground water level becomes an important topic. In this study, the grey system theory is utilized to investigate the relationship among rainfall, unsaturated water pressure and ground water level. First, the grey relational analysis among ground water level, rainfall and unsaturated water pressure are performed. Six different depths of unsaturated water pressure are used for the grey relational analysis and the depth with the optimal grey relational grade is obtained. Then the GM(1,3) model is established based on sequences of ground water level, rainfall and unsaturated water pressure in the depth with the optimal grey relational grade. Second, the GM(1,2) model is established only using the sequences of ground water level and rainfall data. The comparison of the GM(1,2) and the GM(1,3) models are performed to assess the accuracy of ground water level forecast. Finally, the concept of the time lag is used to reestablish the grey models GM(1,2) and GM(1,3) and predict the variation of ground water level. The results show that the GM(1,3) model has the higher accuracy than the GM(1,2) model for ground water level forecast. The optimal time lag is equal to 23 hours in the study site. The accuracy of the ground water level forecast is higher in the GM(1,3) model with the time lag than the one without it. Keywords:Grey system theory, Ground water level, Rainfall, Unsaturated water pressure.

  12. A comparison of pain level and entropy changes following core stability exercise intervention.

    Science.gov (United States)

    Lee, Taero; Kim, Yoon Hyuk; Sung, Paul S

    2011-07-01

    As reported in our previous studies, the complexity of physiologic time series is a sensitive measure of muscle fatigability. This study compared the differences between 2 different analyses following 4 weeks of core stability exercises (CSE) in subjects with and without chronic low back pain (LBP). We examined whether the observed Shannon (information) entropy, as compared with median frequency (MF), was able to differentiate fatigability of the thoracic and lumbar parts of the erector spinae (ES) muscles following the intervention. In total, 32 subjects participated in this study. There were 13 subjects in the CSE intervention group (average age 50.4 ± 9.1 years) and 19 subjects in the control group (average age 46.6 ± 9.1 years). The CSE group performed the specific exercise intervention, but the control group was asked to maintain their current activity and/or exercise levels. The endurance of the back muscles was determined by using a modified version of the isometric fatigue test as originally introduced by Sorensen. Pain level decreased significantly for all subjects (F=25.29, p=0.001), but there was no difference between groups (F=0.42, p=0.52). The MF was not different between groups following treatment (F=0.81, p=0.37). Although there was no entropy level changes following treatment (F=0.01, p=0.93), the interactions between muscles and groups following treatment were significant (F=7.25, p=0.01). The entropy level decreased in both thoracic ES muscles following intervention in the exercise group, while remaining the same in the control group. Although the change in pain level was not different between groups, the Shannon entropy measure more sensitively differentiated the exercise intervention than did MF. In addition, the results also suggested that complexity is related to muscle fatigue, which corresponds to the values of entropy between groups. Further studies are needed to investigate the effectiveness of nonlinear time series of EMG data for

  13. Antioxidant Properties, Degradation Kinetics and Storage Stability of Drinks Prepared From the Cooking Water of Pigmented Rice

    OpenAIRE

    Adyati Putriekasari Handayani; Yogeshini Ramakrishnan; Roselina Karim; Kharidah Muhammad

    2014-01-01

    Pigmented rice, consisting of black rice and red rice, is known to contain antioxidant compounds in its bran that tend to leach out into the water during cooking. As the rice is usually cooked in excess water which is discarded after cooking, the purpose of this study is therefore, to evaluate the rice cooking water as an antioxidant drink in terms of its antioxidant properties, storage stability and anthocyanin degradation kinetics. The results showed that the percentages of antioxidant extr...

  14. Antifoaming materials studies in G.S. (Girlder sulfide) heavy water plants. Chemical and thermical stability. Pt. 3

    International Nuclear Information System (INIS)

    Delfino, C.A.; Rojo, E.A.

    1988-01-01

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2 MPa, up to 230 deg C). Five commercial surfactants were studied from the point of view of their chemical and thermical stability in order to select the most suitable. (Author) [es

  15. Physical and Oxidative Stability of Flaxseed Oil-in-Water Emulsions Fabricated from Sunflower Lecithins: Impact of Blending Lecithins with Different Phospholipid Profiles.

    Science.gov (United States)

    Liang, Li; Chen, Fang; Wang, Xingguo; Jin, Qingzhe; Decker, Eric Andrew; McClements, David Julian

    2017-06-14

    There is great interest in the formulation of plant-based foods enriched with nutrients that promote health, such as polyunsaturated fatty acids. This study evaluated the impact of sunflower phospholipid type on the formation and stability of flaxseed oil-in-water emulsions. Two sunflower lecithins (Sunlipon 50 and 90) with different phosphatidylcholine (PC) levels (59 and 90%, respectively) were used in varying ratios to form emulsions. Emulsion droplet size, charge, appearance, microstructure, and oxidation were measured during storage at 55 °C in the dark. The physical and chemical stability increased as the PC content of the lecithin blends decreased. The oxidative stability of emulsions formulated using Sunlipon 50 was better than emulsions formulated using synthetic surfactants (SDS or Tween 20). The results are interpreted in terms of the impact of emulsifier type on the colloidal interactions between oil droplets and on the molecular interactions between pro-oxidants and oil droplet surfaces.

  16. The GEWEX water vapor assessment (G-VAP) - results from inter-comparisons and stability analysis

    Science.gov (United States)

    Schroeder, Marc; Lockhoff, Maarit; Shi, Lei

    2017-04-01

    A large variety of water vapour data records is available to date. Without proper background information and understanding of the limitations of available data records, these data may be incorrectly utilised or misinterpreted. The overall goal of assessments of CDRs is to conduct objective and independent evaluations and inter-comparisons in order to point out strengths, differences and limitations and, if possible, to provide reasons for them. The need for such assessments is part of the GCOS guidelines for the generation of data products. The GEWEX Data and Assessments Panel (GDAP) has initiated the GEWEX water vapor assessment (G-VAP) which has the major purpose to quantify the current state of the art in water vapour products (upper tropospheric humidity, specific humidity and temperature profiles as well as total column water vapour) being constructed for climate applications. In order to support GDAP and the general climate analysis community G-VAP intends to answer, among others, the following questions: a) How large are the differences in observed temporal changes in long-term satellite data records of water vapour on global and regional scales? b) Are the differences in observed temporal changes within uncertainty limits? c) What is the degree of homogeneity (break points) of each long-term satellite data record? A general overview of G-VAP will be given. The focus of the presentation will be on observed inconsistencies among the long-term satellite data records as observed by inter-comparisons and comparison to in-situ observations and the stability analysis. On basis of consistently applied tools major differences in state-of-art CDRs have been identified, documented and to a large extend explained. The results and the answers for TCWV are summarized as follows: On global ice free ocean scale the trend estimates among long-term data records were generally found to be significantly different. Maxima in standard deviation among the data records are found

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

    Directory of Open Access Journals (Sweden)

    T. Schöne

    2011-03-01

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

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

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

  18. α-Syntrophin stabilizes catalase to reduce endogenous reactive oxygen species levels during myoblast differentiation.

    Science.gov (United States)

    Moon, Jae Yun; Choi, Su Jin; Heo, Cheol Ho; Kim, Hwan Myung; Kim, Hye Sun

    2017-07-01

    α-Syntrophin is a component of the dystrophin-glycoprotein complex that interacts with various intracellular signaling proteins in muscle cells. The α-syntrophin knock-down C2 cell line (SNKD), established by infecting lentivirus particles with α-syntrophin shRNA, is characterized by a defect in terminal differentiation and increase in cell death. Since myoblast differentiation is accompanied by intensive mitochondrial biogenesis, the generation of intracellular reactive oxygen species (ROS) is also increased during myogenesis. Two-photon microscopy imaging showed that excessive intracellular ROS accumulated during the differentiation of SNKD cells as compared with control cells. The formation of 4-hydroxynonenal adduct, a byproduct of lipid peroxidation during oxidative stress, significantly increased in differentiated SNKD myotubes and was dramatically reduced by epigallocatechin-3-gallate, a well-known ROS scavenger. Among antioxidant enzymes, catalase was significantly decreased during differentiation of SNKD cells without changes at the mRNA level. Of interest was the finding that the degradation of catalase was rescued by MG132, a proteasome inhibitor, in the SNKD cells. This study demonstrates a novel function of α-syntrophin. This protein plays an important role in the regulation of oxidative stress from endogenously generated ROS during myoblast differentiation by modulating the protein stability of catalase. © 2017 Federation of European Biochemical Societies.

  19. Effect of Leaves of Caesalpinia decapetala on Oxidative Stability of Oil-in-Water Emulsions

    Directory of Open Access Journals (Sweden)

    María Gabriela Gallego

    2017-03-01

    Full Text Available Caesalpinia decapetala (Roth Alston (Fabaceae (CD is used in folk medicine to prevent colds and treat bronchitis. This plant has antitumor and antioxidant activity. The antioxidant effects of an extract from Caesalpinia decapetala (Fabaceae were assessed by storage of model food oil-in-water emulsions with analysis of primary and secondary oxidation products. The antioxidant capacity of the plant extract was evaluated by the diphenylpicrylhydrazyl (DPPH, Trolox equivalent antioxidant capacity (TEAC, oxygen radical absorbance capacity (ORAC and ferric reducing antioxidant power (FRAP assays and by electron paramagnetic resonance (EPR spectroscopy. Lyophilized extracts of CD were added at concentrations of 0.002%, 0.02% and 0.2% into oil-in-water emulsions, which were stored for 30 days at 33 ± 1 °C, and then, oxidative stability was evaluated. The CD extract had high antioxidant activity (700 ± 70 µmol Trolox/g dry plant for the ORAC assay, mainly due to its phenolic components: gallic acid, quercetin, catechin, 4-hydroxybenzoic acid and p-coumaric acid. At a concentration of 0.2%, the extract significantly reduced the oxidative deterioration of oil-in-water emulsions. The results of the present study show the possibility of utilizing CD as a promising source of natural antioxidants for retarding lipid oxidation in the food and cosmetic industries.

  20. Stability of cemented dried water hyacinth used for biosorption of radionuclides under various circumstances

    Energy Technology Data Exchange (ETDEWEB)

    Saleh, H.M., E-mail: hosamsaleh70@yahoo.com

    2014-03-15

    This paper investigates the influence of frost attack and flooding conditions during disposal on the compressive strength, porosity and durability of cemented waste form contained dried and grinded water hyacinth. This plant was used as a phytoremediating agent to treat liquid waste simulate contaminated with radionuclides. The obtained results showed that an increase in the incorporated dry plants decreases the compressive strength and increases the porosity of the solidified waste form. Raising the number of freeze–thaw cycles was accompanied with noticeable increase in the mass-loss of tested specimens and unsteady trend of compressive strength and consequently the mechanical integrity. The presence and increase of immersion duration per turned positively the mass change and affect in different ways on the solidified waste form. Spectroscopic analyses such as infrared and X-ray as well as microscopic investigation were performed to evaluate the solidified waste form exposed to different undesirable climatic conditions during extending disposal durations. The use of Portland cement as a stabilizer for water hyacinth, following the phytoremediation process, achieves the requirements for durability and strength against the freeze–thaw cycles or flooding in different types of water during prolonged disposal.

  1. Possible mechanism of formation and stability of anomalous states of water

    Energy Technology Data Exchange (ETDEWEB)

    Wong, C.Y. [Oak Ridge National Lab., TN (United States); Lo, S.Y. [American Technology Group, Monrovia, CA (United States)]|[California Inst. of Tech., Pasadena, CA (United States). Dept. of Chemistry

    1998-01-01

    The authors examine the physical processes which are involved in the formation and stability of the anomalous states of water reported recently. The initial step of adding a small amount of ionic compound X{sup +}Y{sup {minus}} to pure water leads t the formation of water clusters X{sup +} (H{sub 2}O){sub n} and Y{sup {minus}} (H{sub 2}O){sub n} with n {much_gt} 1. The structure of the cluster around the ion depends sensitively on the equation of state. The authors explore the consequences of possible polymorphic states of H{sub 2}O in the liquid phase at room temperature. If there are low-lying polymorphic states, the local dipole moment and the local density will change discontinuously as a function of the radial distance from the ion, and regions of different polymorphic states will be found at different separations from the ion. Fragmentation of the cluster by vigorous shaking may break up the cluster into small domains to allow subsequent coalescence of these domains or the growth of the domains as seeds to form greater domains of polymorphic states. Further experimental and theoretical analyses are needed to study these pictures.

  2. Kaolinite and Silica Dispersions in Low-Salinity Environments: Impact on a Water-in-Crude Oil Emulsion Stability

    Directory of Open Access Journals (Sweden)

    Vladimir Alvarado

    2011-10-01

    Full Text Available This research aims at providing evidence of particle suspension contributions to emulsion stability, which has been cited as a contributing factor in crude oil recovery by low-salinity waterflooding. Kaolinite and silica particle dispersions were characterized as functions of brine salinity. A reference aqueous phase, representing reservoir brine, was used and then diluted with distilled water to obtain brines at 10 and 100 times lower Total Dissolved Solid (TDS. Scanning Electron Microscope (SEM and X-ray Diffraction (XRD were used to examine at the morphology and composition of clays. The zeta potential and particle size distribution were also measured. Emulsions were prepared by mixing a crude oil with brine, with and without dispersed particles to investigate emulsion stability. The clay zeta potential as a function of pH was used to investigate the effect of particle charge on emulsion stability. The stability was determined through bottle tests and optical microscopy. Results show that both kaolinite and silica promote emulsion stability. Also, kaolinite, roughly 1 mm in size, stabilizes emulsions better than larger clay particles. Silica particles of larger size (5 µm yielded more stable emulsions than smaller silica particles do. Test results show that clay particles with zero point of charge (ZPC at low pH become less effective at stabilizing emulsions, while silica stabilizes emulsions better at ZPC. These result shed light on emulsion stabilization in low-salinity waterflooding.

  3. IGF-IR promotes prostate cancer growth by stabilizing α5β1 integrin protein levels.

    Directory of Open Access Journals (Sweden)

    Aejaz Sayeed

    Full Text Available Dynamic crosstalk between growth factor receptors, cell adhesion molecules and extracellular matrix is essential for cancer cell migration and invasion. Integrins are transmembrane receptors that bind extracellular matrix proteins and enable cell adhesion and cytoskeletal organization. They also mediate signal transduction to regulate cell proliferation and survival. The type 1 insulin-like growth factor receptor (IGF-IR mediates tumor cell growth, adhesion and inhibition of apoptosis in several types of cancer. We have previously demonstrated that β1 integrins regulate anchorage-independent growth of prostate cancer (PrCa cells by regulating IGF-IR expression and androgen receptor-mediated transcriptional functions. Furthermore, we have recently reported that IGF-IR regulates the expression of β1 integrins in PrCa cells. We have dissected the mechanism through which IGF-IR regulates β1 integrin expression in PrCa. Here we report that IGF-IR is crucial for PrCa cell growth and that β1 integrins contribute to the regulation of proliferation by IGF-IR. We demonstrate that β1 integrin regulation by IGF-IR does not occur at the mRNA level. Exogenous expression of a CD4 - β1 integrin cytoplasmic domain chimera does not interfere with such regulation and fails to stabilize β1 integrin expression in the absence of IGF-IR. This appears to be due to the lack of interaction between the β1 cytoplasmic domain and IGF-IR. We demonstrate that IGF-IR stabilizes the β1 subunit by protecting it from proteasomal degradation. The α5 subunit, one of the binding partners of β1, is also downregulated along with β1 upon IGF-IR knockdown while no change is observed in the expression of the α2, α3, α4, α6 and α7 subunits. Our results reveal a crucial mechanistic role for the α5β1 integrin, downstream of IGF-IR, in regulating cancer growth.

  4. Evapotranspiration Partitioning and Response to Abnormally Low Water Levels in a Floodplain Wetland in China

    Directory of Open Access Journals (Sweden)

    Xiaosong Zhao

    2016-01-01

    Full Text Available Evapotranspiration (ET is an important component of the wetland water budget. Water level declines in Poyang Lake, the largest freshwater lake in China, have caused concerns, especially during low water levels. However, how wetland ET and its partitioning respond to abnormally low water levels is unclear. In this study, wetland ET was estimated with MODIS data and meteorological data. The wetland ET partitioning and its relationship with abnormally low water levels were analyzed for 2000–2013. The results showed that the water evaporation rate (Ewater was larger than the land ET rate (ETland; the ETland/Ewater ranged from 0.77 to 0.99. When the water level was below 12.8 m, the ET partition ratio was larger than 1, which indicates that wetland ET comes from land surface ET more than water evaporation. The negative standardized water level index (SWI was used to represent an abnormally low water level in the wetland. Although the monthly wetland ET decreased as the negative SWI decreased, ETland was higher than the average under negative SWI conditions from September to December, when the water level decreased. The abnormally low water level induced more water loss from the land surface, especially when the water level decreased, which reduced the available water resources along the wetland shore.

  5. Nonlinear dynamics and stability of boiling water reactors: qualitative and quantitative analyses

    International Nuclear Information System (INIS)

    March-Leuba, J.; Cacuci, D.G.; Perez, R.B.

    1985-01-01

    A phenomenological model has been developed to simulate the qualitative behavior of boiling water reactors (BWRs) in the nonlinear regime under deterministic and stochastic excitations. After the linear stability threshold is crossed, limit cycle oscillations appear due to interactions between two unstable equilibrium points and the phase-space trajectories. This limit cycle becomes unstable when the feedback gain exceeds a certain critical value. Subsequent limit cycle instabilities produce a cascade of period-doubling bifurcations that leads to a periodic pulsed behavior. Under stochastic excitations, BWRs exhibit a single characteristic resonance, at approx.0.5 Hz, in the linear regime. By contrast, this work shows that harmonics of this characteristic frequency appear in the nonlinear regime. Furthermore, this work also demonstrates that amplitudes of the limit cycle oscillations do not depend on the variance of the stochastic excitation and remain bounded at all times. A physical model of nonlinear BWR dynamics has also been developed and employed to calculate the amplitude of limit cycle oscillations and their effects on fuel integrity over a wide range of operating conditions in the Vermont Yankee reactor. These calculations have confirmed that, beyond the threshold for linear stability, the reactor's state variable undergo limit cycle oscillations

  6. Effect of yttria addition on the stability of porous chromium oxide ceramics in supercritical water

    International Nuclear Information System (INIS)

    Dong Ziqiang; Chen Weixing; Zheng Wenyue; Guzonas, Dave

    2013-01-01

    Porous chromium oxide (Cr 2 O 3 ) ceramics were prepared by oxidizing highly porous chromium carbides that were obtained by a reactive sintering method, and were evaluated at temperatures ranging from 375 °C to 625 °C in supercritical water (SCW) environments with a fixed pressure of 25–30 MPa. Reactive element yttrium was introduced to the porous oxide ceramic by adding various amounts of yttria of 5, 10 and 20 wt.%, respectively, prior to reactive sintering. The exposure in SCW shows that the porous chromium oxide is quite stable in SCW at 375 °C. However, the stability decreased with increasing temperature. It is well known that chromium oxide can be oxidized to soluble chromium (VI) species in SCW when oxygen is present. Adding yttria increases the stability of chromium oxide in SCW environments. However, adding yttria higher than 5 wt.% increased the weight loss of porous chromium oxide samples because of the direct dissociation of Y 2 O 3 in SCW.

  7. Formulation and stability of whitening VCO-in-water nano-cream.

    Science.gov (United States)

    Al-Edresi, Sarmad; Baie, Saringat

    2009-05-21

    Virgin coconut oil (VCO)-in-water, nano-emulsion in the form of cream stabilized by Emulium Kappa as an emulsifier, was prepared by using the Emulsion Inversion Point method. A nano-emulsion with droplet size cosmetic industries. Emulium Kappa is an ionic emulsifier that contains sodium stearoyl lactylate, the active whitening ingredient was Kojic Dipalmitate. Ostwald ripening is the main destabilizing factor for the nano-emulsion. This decline can be reduced by adding non-soluble oil, namely squalene, to the virgin coconut oil. We tested VCO:squalene in the ratios of 10:0, 9.8:0.2, 9.6:0.4, 9.4:0.6, 9.2:0.8, 9:1 and 8:2 and discovered that squalene's higher molecular weight (above critical molecular weight) resulted in low polarity and insolubility in the continuous phase. The continuous partitioning between the droplets results in the decline of Ostwald ripening. Furthermore, flocculation may occur due to the instability of nano-emulsion, especially for the preparations with little or no squalene at all. The stability of the nano-emulsion was evaluated by the electrophoretic properties of the emulsion droplets. The zeta potential values for the emulsion increased as the percentage of squalene oil increased.

  8. Strontium Zirconate TBC Sprayed by a High Feed-Rate Water-Stabilized Plasma Torch

    Science.gov (United States)

    Ctibor, P.; Nevrla, B.; Cizek, J.; Lukac, F.

    2017-12-01

    A novel thermal barrier coating (TBC) material, strontium zirconate SrZrO3, was sprayed by a high feed-rate water-stabilized plasma torch WSP 500. Stainless steel coupons were used as substrates. Coatings with a thickness of about 1.2 mm were produced, whereas the substrates were preheated over 450 °C. The torch worked at 150 kW power and was able to spray SrZrO3 with a high spray rate over 10 kg per hour. Microstructure and microhardness, phase composition, adhesion, thermal conductivity and thermal expansion were evaluated. The coating has low thermal conductivity under 1 W/m K in the interval from room temperature up to 1200 °C. Its crystallite size is slightly over 400 nm and thermal expansion 12.3 µm K-1 in the similar temperature range.

  9. Stability of the barium–benzo-15-crown-5 complex in nitrobenzene saturated with water

    Directory of Open Access Journals (Sweden)

    E. MAKRLÍK

    2006-11-01

    Full Text Available From extraction experiments and g-activity measurements, the exchange extraction constant corresponding to the equilibrium Ba2+(aq + SrL22+(nb D BaL22+(nb + Sr2+(aq occurring in the two-phase water–nitrobenzene system (L =benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase was evaluated as log Kex (Ba2+, SrL22+ = 0.3 ± 0.1. Furthermore, the stability constant of the benzo-15-crown-5–barium complex in nitrobenzene saturated with water was calculated for the temperature of 25 °C: log bnb (BaL22+=13.3±0.1.

  10. Stability analysis of Eulerian-Lagrangian methods for the one-dimensional shallow-water equations

    Science.gov (United States)

    Casulli, V.; Cheng, R.T.

    1990-01-01

    In this paper stability and error analyses are discussed for some finite difference methods when applied to the one-dimensional shallow-water equations. Two finite difference formulations, which are based on a combined Eulerian-Lagrangian approach, are discussed. In the first part of this paper the results of numerical analyses for an explicit Eulerian-Lagrangian method (ELM) have shown that the method is unconditionally stable. This method, which is a generalized fixed grid method of characteristics, covers the Courant-Isaacson-Rees method as a special case. Some artificial viscosity is introduced by this scheme. However, because the method is unconditionally stable, the artificial viscosity can be brought under control either by reducing the spatial increment or by increasing the size of time step. The second part of the paper discusses a class of semi-implicit finite difference methods for the one-dimensional shallow-water equations. This method, when the Eulerian-Lagrangian approach is used for the convective terms, is also unconditionally stable and highly accurate for small space increments or large time steps. The semi-implicit methods seem to be more computationally efficient than the explicit ELM; at each time step a single tridiagonal system of linear equations is solved. The combined explicit and implicit ELM is best used in formulating a solution strategy for solving a network of interconnected channels. The explicit ELM is used at channel junctions for each time step. The semi-implicit method is then applied to the interior points in each channel segment. Following this solution strategy, the channel network problem can be reduced to a set of independent one-dimensional open-channel flow problems. Numerical results support properties given by the stability and error analyses. ?? 1990.

  11. Investigation of Water Holding Capacity of Sugarcane Mulch for Sand Dune Stabilization in Ahvaz

    Directory of Open Access Journals (Sweden)

    T. Jamili

    2017-01-01

    sugarcane mulches was also carried out. Materials and Methods: The experiments were conducted in the soil laboratory of Khuzestan-Ramin University of Agricultural and Natural Resources. For this purpose, Vinasse and clay soil samples were used to make sugarcane mulches. Different quantities of Vinase, Filter Kike, and clay samples were mixed in water to select the best batch mix (by trial and error. A mulch sprayer was then used to spray the batch mixes on sand dune beds packed in trays 1054510cm. In addition, the same procedures were employed to choose an oil mulch treatment as control for comparison with sugarcane mulch treatments. Water holding capacity was measured in 100, 333, 1000, 5000, 10000, 15000 hPa suction by pressure plate and Macro elements ( N, P, K and microelements (Fe, Cu, Zn were determined by conventional methods and atomic absorption in each treatment. Experiments were carried out using a factorial experiment with a completely random design in threereplicants. Results and Discussion: The wide range of pH values obtained were dependent on the different batch mixes of Vinase, clay soil, and Filter Kike. Reaction (pH of Vinase was lower (5.00 than those of Filter Kike (7.5 and soil (8.07. EC and SAR values of treatments were both affected by Vinase, soil, and Filter Kike. This could be due to the higher EC and the low level of SAR in Vinase in contrast to soil and Filter Kike. EC and SAR are two major chemical factors known to affect sand dune stabilization (Bresler, 1982. Based on Table 3, N, P, K, Fe, Zn, and Cu in sugarcane mulches varied from 0.15-0.66 (%, 10.82-28.46 (mg.Kg-1, 133.01-633.33 (meq.Li-1, 15.22-36.76 (mg.Kg-1, 2.19-2.93 (mg.Kg-1, and 0.92-4.1 (mg.Kg-1, respectively. The results revealed that sugarcane mulches are rich in N, P, and K that are essential in soil fertility. The results determined that there was significant effect (p

  12. Elucidation of stabilizing oil-in-water Pickering emulsion with different modified maize starch-based nanoparticles.

    Science.gov (United States)

    Ye, Fan; Miao, Ming; Jiang, Bo; Campanella, Osvaldo H; Jin, Zhengyu; Zhang, Tao

    2017-08-15

    The aim of present study was to study the medium-chain triacylglycerol-in-water (O/W) Pickering emulsion stabilized using different modified starch-based nanoparticles (octenylsuccinylation treated soluble starch nanoparticle, OSA-SSNP, and insoluble starch nanoparticle, ISNP). The major factors for affecting the system stability, rheological behaviour and microstructure of the emulsions were also investigated. The parameters of the O/W emulsions stabilized by OSA-SSNP or ISNP were selected as follows: 3.0% of starch nanoparticles concentration, 50% of MCT fraction and 7.0 of system pH. The rheological properties indicated that both emulsions displayed shear-thinning behaviour as a non-Newtonian fluid. For OSA-SSNP, the viscosities of the emulsion were higher than those of ISNP throughout shear rate range for the same condition. The plot of droplet size distribution for emulsion stabilized OSA-SSNP appeared as a single narrow peak, whereas a broader droplet size distribution with bimodal pattern was observed for emulsion stabilized ISNP. The microscopy results showed that both OSA-SSNP and ISNP were adsorbed at oil-water interface to form a barrier film and retard the phase separation. When emulsion was stored for 30d, no phase separation was detected for O/W emulsion, revealing high stability of emulsion stabilized by both OSA-SSNP and ISNP. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Self-esteem level and stability, admission functional status, and depressive symptoms in acute inpatient stroke rehabilitation.

    Science.gov (United States)

    Vickery, Chad D; Sepehri, Arash; Evans, Clea C; Jabeen, Linsa N

    2009-11-01

    Explore the relationship of self-esteem level, self-esteem stability, and admission functional status on discharge depressive symptoms in acute stroke rehabilitation. One hundred twenty stroke survivors serially completed a measure of state self-esteem during inpatient rehabilitation and completed a measure of depressive symptoms at discharge. Functional status was rated at admission using the Functional Independence Measure (FIM). Regressions explored main effects and interactions of self-esteem level and stability and admission FIM self-care, mobility, and cognitive functioning on discharge depressive symptoms. After controlling for potential moderating variables, self-esteem level interacted with FIM self-care and cognitive functioning to predict discharge depressive symptoms, such that survivors with lower self-rated self-esteem and poorer functional status indicated higher levels of depressive symptoms. Self-esteem stability interacted with FIM mobility functioning, such that self-esteem instability in the presence of lower mobility functioning at admission was related to higher depressive symptoms at discharge. These results suggest that self-esteem variables may moderate the relationship between functional status and depressive symptoms. Self-esteem level and stability may differentially moderate functional domains, although this conclusion requires further empirical support.

  14. Water quality and some nutrient levels in Shiroro Lake, Niger State ...

    African Journals Online (AJOL)

    Water quality and some nutrient levels in Shiroro Lake, Niger State, Nigeria. ... Water physical and chemical properties and nutrient levels of the surface water of Shiroro Lake (Nigeria) were determined over a period of eighteen months from June ... Key Words: Nutrient, water parameters, Shiroro Lake tributaries, Nigeria.

  15. Water Security at Local Government Level: What do People Think?

    CSIR Research Space (South Africa)

    Meissner, Richard

    2016-06-01

    Full Text Available and vandalism has an immediate impact on water security. • Problem in both municipalities - ‘No water no farming’ - Quality – armed robbery at Groblersdal WWTW. - Quantity – theft of water pipeline to Motetema – rioting. • High price of scrap metal is part...

  16. in_focus - Water: Local-level Management | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Today, more than 1 billion people lack access to safe drinking water. Within the next 25 years, fully one-third of the world's population will experience severe water scarcity. It is clear that disparities in the availability and supply of fresh water are truly a matter of life and death, and constitute one of the great governance ...

  17. Low-Cost Alternative for the Measurement of Water Levels in Surface Water Streams

    Directory of Open Access Journals (Sweden)

    Luis E. PEÑA

    2017-11-01

    Full Text Available Flood risk management and water resources planning involve a deep knowledge of surface streams so that mitigation strategies and climate change adaptations can be implemented. Commercially, there is a wide range of technologies for the measurement of hydroclimatic variables; however, many of these technologies may not be affordable for institutions with limited budgets. This paper has two main objectives: 1 Present the design of an ultrasound-based water level measurement system, and 2 Propose a methodological alternative for the development of instruments, according to the needs of institutions conducting monitoring of surface waterbodies. To that end, the proposed methodology is based on selection processes defined according to the specific needs of each waterbody. The prototype was tested in real-world scale, with the potential to obtain accurate measurements. Lastly, we present the design of the ultrasound-based water level measurement instrument, which can be built at a low cost. Low-cost instruments can potentially contribute to the sustainable instrumental autonomy of environmental entities and help define measurement and data transmission standards based on the specific requirements of the monitoring.

  18. Geographical distribution of drinking-water with high iodine level and association between high iodine level in drinking-water and goitre: a Chinese national investigation.

    Science.gov (United States)

    Shen, Hongmei; Liu, Shoujun; Sun, Dianjun; Zhang, Shubin; Su, Xiaohui; Shen, Yanfeng; Han, Hepeng

    2011-07-01

    Excessive iodine intake can cause thyroid function disorders as can be caused by iodine deficiency. There are many people residing in areas with high iodine levels in drinking-water in China. The main aim of the present study was to map the geographical distribution of drinking-water with high iodine level in China and to determine the relationship between high iodine level in drinking-water and goitre prevalence. Iodine in drinking-water was measured in 1978 towns of eleven provinces in China, with a total of 28,857 water samples. We randomly selected children of 8-10 years old, examined the presence of goitre and measured their urinary iodine in 299 towns of nine provinces. Of the 1978 towns studied, 488 had iodine levels between 150 and 300 μg/l in drinking-water, and in 246 towns, the iodine level was >300 μg/l. These towns are mainly distributed along the original Yellow River flood areas, the second largest river in China. Of the 56 751 children examined, goitre prevalence was 6.3 % in the areas with drinking-water iodine levels of 150-300 μg/l and 11.0 % in the areas with drinking-water iodine >300 μg/l. Goitre prevalence increased with water and urinary iodine levels. For children with urinary iodine >1500 μg/l, goitre prevalence was 3.69 times higher than that for those with urinary iodine levels of 100-199 μg/l. The present study suggests that drinking-water with high iodine levels is distributed in eleven provinces of China. Goitre becomes more prevalent with the increase in iodine level in drinking-water. Therefore, it becomes important to prevent goitre through stopping the provision of iodised salt and providing normal drinking-water iodine through pipelines in these areas in China.

  19. Water level response measurement in a steel cylindrical liquid storage tank using image filter processing under seismic excitation

    Science.gov (United States)

    Kim, Sung-Wan; Choi, Hyoung-Suk; Park, Dong-Uk; Baek, Eun-Rim; Kim, Jae-Min

    2018-02-01

    Sloshing refers to the movement of fluid that occurs when the kinetic energy of various storage tanks containing fluid (e.g., excitation and vibration) is continuously applied to the fluid inside the tanks. As the movement induced by an external force gets closer to the resonance frequency of the fluid, the effect of sloshing increases, and this can lead to a serious problem with the structural stability of the system. Thus, it is important to accurately understand the physics of sloshing, and to effectively suppress and reduce the sloshing. Also, a method for the economical measurement of the water level response of a liquid storage tank is needed for the exact analysis of sloshing. In this study, a method using images was employed among the methods for measuring the water level response of a liquid storage tank, and the water level response was measured using an image filter processing algorithm for the reduction of the noise of the fluid induced by light, and for the sharpening of the structure installed at the liquid storage tank. A shaking table test was performed to verify the validity of the method of measuring the water level response of a liquid storage tank using images, and the result was analyzed and compared with the response measured using a water level gauge.

  20. Predicting the residual aluminum level in water treatment process

    OpenAIRE

    J. Tomperi; M. Pelo; K. Leiviskä

    2013-01-01

    In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease. Thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP) was analyzed and the residual aluminum in drinking water was predicted usi...

  1. Predicting the residual aluminum level in water treatment process

    OpenAIRE

    J. Tomperi; M. Pelo; K. Leiviskä

    2012-01-01

    In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP) was analyzed and the residual aluminum in drinking water was predicted usin...

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

    International Nuclear Information System (INIS)

    Kuan, C.C.; Lin, C.; Hsu, C.C.

    1992-01-01

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

  3. Stabilization of the arrival time of a relativistic electron beam to the 50 fs level

    Science.gov (United States)

    Roberts, J.; Skowronski, P.; Burrows, P. N.; Christian, G. B.; Corsini, R.; Ghigo, A.; Marcellini, F.; Perry, C.

    2018-01-01

    We report the results of a low-latency beam phase feed-forward system built to stabilize the arrival time of a relativistic electron beam. The system was operated at the Compact Linear Collider (CLIC) Test Facility (CTF3) at CERN where the beam arrival time was stabilized to approximately 50 fs. The system latency was 350 ns and the correction bandwidth >23 MHz . The system meets the requirements for CLIC.

  4. Impacts of water level fluctuation on mesotrophic rich fens: acidification versus eutrophication

    NARCIS (Netherlands)

    Cusell, C.; Lamers, L.P.M.; van Wirdum, G.; Kooijman, A.

    2013-01-01

    Water levels in areas with intensive agriculture have often been strictly controlled for decades. Recently, more natural fluctuating water levels have been propagated to improve the ecological quality of wetlands in these areas. This study investigated the effects of water levels on protected

  5. The Influence of Chemically Modified Potato Maltodextrins on Stability and Rheological Properties of Model Oil-in-Water Emulsions

    Directory of Open Access Journals (Sweden)

    Karolina Pycia

    2018-01-01

    Full Text Available The aim of this study was to determine the effect of the maltodextrins prepared from chemically modified starches (crosslinked, stabilized, crosslinked and stabilized on the stability and rheological properties of model oil-in-water (o/w emulsions. Based on the obtained results, it was concluded that emulsion stability depended on hydrolysates dextrose equivalent (DE value. Maltodextrin with the lowest degree of depolymerization effectively stabilized the dispersed system, and the effectiveness of this action depended on the maltodextrin type and concentration. Addition of distarch phosphate-based maltodextrin stabilized emulsion at the lowest applied concentration, and the least effective was maltodextrin prepared from acetylated starch. Emulsions stabilized by maltodextrins (DE 6 prepared from distarch phosphate and acetylated distarch adipate showed the predominance of the elastic properties over the viscous ones. Only emulsion stabilized by maltodextrin prepared from distarch phosphate (E1412 revealed the properties of strong gel. Additionally, the decrease in emulsions G′ and G″ moduli values, combined with an increase in the value of DE maltodextrins, was observed.

  6. Stabilized liquid membrane device (SLMD) for the passive, integrative sampling of labile metals in water

    Science.gov (United States)

    Brumbaugh, W.G.; Petty, J.D.; Huckins, J.N.; Manahan, S.E.

    2002-01-01

    A stabilized liquid membrane device (SLMD) is described for potential use as an in situ, passive, integrative sampler for cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in natural waters. The SLMD (patent pending) consists of a 2.5-cm-wide by 15-cm-long strip of low-density polyethylene (LDPE) layflat tubing containing 1 mL of an equal mixture (v/v) of oleic acid (cis-9-octadecenoic acid) and EMO-8Q (7-[4-ethyl-1-methyloctyl]-8-quinolinol). The reagent mixture continuously diffuses to the exterior surface of the LDPE membrane, and provides for sequestration of several divalent metals for up to several weeks. Depending on sampler configuration, concentration factors of several thousand can be realized for these metal ions after just a few days. In addition to in situ deployment, the SLMD may be useful for laboratory determination of labile metal species in grab samples. Methods for minimizing the effects of water flow on the sampling rate are currently under investigation.

  7. Amorphous nano-curcumin stabilized oil in water emulsion: Physico chemical characterization.

    Science.gov (United States)

    Aditya, N P; Hamilton, Ian E; Norton, Ian T

    2017-06-01

    Particle characteristics e.g. size and polymorphism are known to significantly affect the Pickering ability of the solid particles by influencing their interaction at the oil and water (O/W) interface. In this study, nano-sized amorphous curcumin particles were fabricated using nanonization technology to use them as Pickering particles. After nanonization, native crystalline curcumin particles were converted into amorphous, nanosized particles of ∼220nm. Amorphous nature of the particle was evident from the decreased melting point from 177±1°C (native curcumin) to 146±3°C (nanonized curcumin) and enthalpy from 27±2J/g to 3.5±1J/g. Interfacial tension (IFT) studies have shown a decrease in IFT at the O/W interface from ∼27mN/m to ∼15mN/m in the presence of amorphous curcumin particles in water phase compared to crystalline curcumin particles. Curcumin stabilized O/W emulsion has an initial droplet size of ∼1.2μm and they were stable for 30days at 4°C. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Level and Stability of Self-Esteem as Predictors of Children's Intrinsic Motivation and Reasons for Anger.

    Science.gov (United States)

    Waschull, Stefanie B.; Kernis, Michael H.

    1996-01-01

    Examines the extent to which level and stability of fifth-grade children's self-esteem predicted achievement motivation and reasons for anger. Findings indicate that the more unstable the children's self-esteem, the lower their scores on measures of curiosity/interest and preference for challenge, and the greater the likelihood that they would…

  9. How geomorphology and groundwater level affect the spatio-temporal variability of riverine cold water patches?

    Science.gov (United States)

    Wawrzyniak, Vincent; Piégay, Hervé; Allemand, Pascal; Vaudor, Lise; Goma, Régis; Grandjean, Philippe

    2016-04-01

    Temperature is a key factor for river ecosystems. In summer, patches of cold water are formed in the river by groundwater seepage. These patches have strong ecological significance and extend to the surface water in a well-mixed riverine system. These patches can serve as thermal refuges for some fish species during summer. In this study, the temporal variability and spatial distribution of cold water patches were explored along a 50 km river reach (the lower Ain River, France) using thermal infrared airborne remote sensing. This study examines a new range of processes acting on cold water patches at different scales that have not previously been touched upon in the literature. Three airborne campaigns were conducted during the summers of 2010, 2011 and 2014. Based on these images, a large number of cold water patches were identified using an automated method. Four types of patches were observed: tributary plumes, cold side channels (former channels or point-bar backwater channels), side seeps (located directly in the river channel) and gravel bar seeps (occurring at the downstream end of gravel bars). Logistic regression was used to analyse the longitudinal distribution of cold water patches according to geomorphologic indicators reflecting current or past fluvial process. Side seeps were found to be related to the local geology. Cold side channels were correlated to contemporary and past lateral river mobility. Gravel bar seeps were related to the current development of bars and are more prevalent in wandering reaches than in single-bed incised and paved reaches. The logistic model was subsequently used to evaluate gravel bar seep variability in the past. The model suggests larger numbers of seeps in the mid-20th century when bar surface area was higher. Interannual variability in the occurrence and spatial extent of side seeps and gravel bar seeps appear to be related to groundwater level fluctuations. Cold side channels exhibited greater interannual stability

  10. North Atlantic Coast Comprehensive Study Phase I: Statistical Analysis of Historical Extreme Water Levels with Sea Level Change

    Science.gov (United States)

    2014-09-01

    generally rising as a result of regional water body thermal expansion. The Intergovernmental Panel on Climate Change ( IPCC ) AR4 ( IPCC 2007) estimate of...assessing potential measures/projects that would reduce flood risk and increase resiliency. Potential future climate change must be included in the risk...level time series are detrended prior to the computation of storm surge because the observed water levels exhibit the effects of sea level change and

  11. The nuclear physical method for high pressure steam manifold water level gauging and its error

    International Nuclear Information System (INIS)

    Li Nianzu; Li Beicheng; Jia Shengming

    1993-10-01

    A new method, which is non-contact on measured water level, for measuring high pressure steam manifold water level with nuclear detection technique is introduced. This method overcomes the inherent drawback of previous water level gauges based on other principles. This method can realize full range real time monitoring on the continuous water level of high pressure steam manifold from the start to full load of boiler, and the actual value of water level can be obtained. The measuring errors were analysed on site. Errors from practical operation in Tianjin Junliangcheng Power Plant and in laboratory are also presented

  12. The effect of nanofluid stability on critical heat flux using magnetite-water nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Hyuk [Thermal-Hydraulic Safety Research Division, Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kam, Dong Hoon [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Jeong, Yong Hoon, E-mail: jeongyh@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2015-10-15

    Highlights: • We conduct the CHF experiment with magnetite-water nanofluid. • Nanofluids should be initially sonicated to enhance the CHF. • Nanofluids have the limited concentration to guarantee CHF enhancement. • CHF enhancement using nanofluids can be guaranteed for a year at least. - Abstract: In nuclear safety, the critical heat flux (CHF) is a very important value that can determine the limit of the safety design. To prevent a minor nuclear accident from mitigating into a severe accident, the coolants should have a higher CHF value. Among the strategies to improve the CHF, many feasibility studies using several kinds of nanofluids were performed as an alternative coolant because of the abnormally CHF enhancement with a very small volume fraction of nanoparticles. Although many researches have tried to apply nanofluids into a real system as a coolant, there are some problems left to solve. In particular, it is necessary to understand the characteristics of nanoparticle stability in the base fluid in order to guarantee the thermal performance of the nanofluids. In this study, three kinds of effects were considered to clarify the relation between nanofluid stability and CHF improvement: the effect of sonication, dilution, and storage time. The effect of sonication in the manufacturing process of the nanofluids should be considered. A two-step method is the most popular for manufacturing nanofluids. Based on the results of the present study, nanofluids made through a two-step method should be initially sonicated to guarantee their CHF enhancement. In the process of dilution, the limitation of nanoparticle concentration exists in the process of dilution to guarantee CHF enhancement. Finally, CHF enhancement using a nanofluid made by a two-step method can be guaranteed for at least a year. In addition, we also proved that CHF using nanofluids can be decreased according to the preservation time.

  13. Regional Water Table (1998) and Ground-Water-Level Changes in the Mojave River, and the Morongo Ground-Water Basins, San Bernardino County, California

    Science.gov (United States)

    Smith, Gregory A.; Pimentel, M. Isabel

    2000-01-01

    The Mojave River and the Morongo ground-water basins are in the southwestern part of the Mojave Desert in southern California. Ground water from these basins supplies a major part of the water requirements for the region. The rapid and continuous population growth in this area has resulted in ever-increasing demands on local ground-water resources. The continuing collection and interpretation of ground-water data helps local water districts, military bases, and private citizens gain a better understanding of the ground-water systems and, consequently, water availability. During 1998 the U.S. Geological Survey and other agencies made approximately 2,370 water-level measurements in the Mojave River and the Morongo ground-water basins. These data document recent conditions and changes in ground-water levels. A water-level contour map was drawn using data from 450 wells, providing coverage for most of both basins. Twenty-three hydrographs show long-term (as much as 70 years) water-level trends throughout the basins. To help show effects of late seasonal recharge along the Mojave River, 14 short-term (13 years) hydrographs were created. A water-level change map was compiled to enable comparison of 1996 and 1998 water levels. The Mojave River and the Morongo ground-water basins had little change in water levels between 1996 and 1998 - with the exception of the areas of the Yucca Valley affected by artificial recharge. Other water-level changes were localized and reflected pumping or measurements made before seasonal recharge. Three areas of perched ground water were identified: El Mirage Lake (dry), Adelanto, and Lucerne Valley.

  14. Water-Soluble N-Heterocyclic Carbene-Protected Gold Nanoparticles: Size-Controlled Synthesis, Stability, and Optical Properties

    OpenAIRE

    Salorinne, Kirsi; Man, Renee W.Y.; Li, Chien-Hung; Taki, Masayasu; Nambo, Masakazu; Crudden, Cathleen M.

    2017-01-01

    NHC-Au(I) complexes were used to prepare stable, water-soluble, NHC-protected gold nanoparticles. The water-soluble, charged nature of the nanoparticles permitted analysis by polyacrylamide gel electrophoresis (PAGE), which showed that the nanoparticles were highly monodisperse, with tunable core diameters between 2.0 and 3.3 nm depending on the synthesis conditions. Temporal, thermal, and chemical stability of the nanoparticles were determined to be high. Treatment with thiols caused etching...

  15. determination of lead at nanogram level in water samples

    African Journals Online (AJOL)

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    As is well known, heavy metal pollution has been a focus of attention all over the world. Metal ions frequently contained in industrial and municipal wastewater can be harmful to aquatic ... an urgent need to develop a simple and sensitive conventional method for measuring lead ion in ..... 5 Drinking water, sea water sample.

  16. Assessing maize foliar water stress levels under field conditions ...

    African Journals Online (AJOL)

    The management of spectral reflectance data to extract information of importance for plant water status has been motivated by knowledge of the availability of specific bands in the electromagnetic spectrum responsible for water absorption. The purpose of this study was to investigate the potential of using selected spectral ...

  17. Assessing Maize Foliar Water Stress Levels Under Field Conditions ...

    African Journals Online (AJOL)

    Abstract: Plant physiological processes required for crop productivity are dependent on the availability of water to crops. Water availability to crops therefore requires real time monitoring for timeous rescue or intervention measures. Such monitoring over vast areas is only possible through remotely sensed techniques such ...

  18. Water-Air Volatilization Factors to Determine Volatile Organic Compound (VOC Reference Levels in Water

    Directory of Open Access Journals (Sweden)

    Vicenç Martí

    2014-06-01

    Full Text Available The goal of this work is the modeling and calculation of volatilization factors (VFs from water to air for volatile organic compounds (VOCs in order to perform human health risk-based reference levels (RLs for the safe use of water. The VF models have been developed starting from the overall mass-transfer coefficients (Koverall concept from air to water for two interaction geometries (flat surface and spherical droplets in indoor and outdoor scenarios. For a case study with five groups of risk scenarios and thirty VOCs, theoretical VFs have been calculated by using the developed models. Results showed that Koverall values for flat and spherical surface geometries were close to the mass transfer coefficient for water (KL when Henry’s law constant (KH was high. In the case of spherical drop geometry, the fraction of volatilization (fV was asymptotical when increasing KH with fV values also limited due to Koverall. VFs for flat surfaces were calculated from the emission flux of VOCs, and results showed values close to 1000KH for the most conservative indoor scenarios and almost constant values for outdoor scenarios. VFs for spherical geometry in indoor scenarios followed also constant VFs and were far from 1000KH. The highest calculated VF values corresponded to the E2A, E2B, E3A and E5A scenarios and were compared with experimental and real results in order to check the goodness of flat and sphere geometry models. Results showed an overestimation of calculated values for the E2A and E2B scenarios and an underestimation for the E3A and E5A scenarios. In both cases, most of the calculated VFs were from 0.1- to 10-times higher than experimental/real values.

  19. Effect of oxygen level on the oxidative stability of two different retail pork products stored using modified atmosphere packaging (MAP)

    DEFF Research Database (Denmark)

    Spanos, Dimitrios; Ann Tørngren, Mari; Christensen, Mette

    2016-01-01

    The characteristics and the oxidative stability of pork steaks and of pork mince were investigated during 2, 5 and 7 days of refrigerated storage using oxygen (O2) levels of 0%, 20%, 50% and 80% in modified atmosphere packaging (MAP). Steaks stored during 7 days were not affected by an increase...... in O2 concentration, as revealed by lipid and protein oxidation markers. In contrast, the mince was characterised by an altered protein profile, loss of free thiol groups and increased protein oxidation, early during storage. The oxidative stability of pork mince was improved by using intermediate (50......%) O2 MAP. The results show that fresh pork products are affected differently by the MAP O2 concentration and strongly indicate that optimisation of MAP based on the retail product type would be of considerable benefit to their oxidative stability....

  20. Effect of oxygen level on the oxidative stability of two different retail pork products stored using modified atmosphere packaging (MAP).

    Science.gov (United States)

    Spanos, Dimitrios; Tørngren, Mari Ann; Christensen, Mette; Baron, Caroline P

    2016-03-01

    The characteristics and the oxidative stability of pork steaks and of pork mince were investigated during 2, 5 and 7days of refrigerated storage using oxygen (O2) levels of 0%, 20%, 50% and 80% in modified atmosphere packaging (MAP). Steaks stored during 7days were not affected by an increase in O2 concentration, as revealed by lipid and protein oxidation markers. In contrast, the mince was characterised by an altered protein profile, loss of free thiol groups and increased protein oxidation, early during storage. The oxidative stability of pork mince was improved by using intermediate (50%) O2 MAP. The results show that fresh pork products are affected differently by the MAP O2 concentration and strongly indicate that optimisation of MAP based on the retail product type would be of considerable benefit to their oxidative stability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Combination of sodium caseinate and succinylated alginate improved stability of high fat fish oil-in-water emulsions

    DEFF Research Database (Denmark)

    Yesiltas, Betül; Sørensen, Ann-Dorit Moltke; García Moreno, Pedro Jesús

    2018-01-01

    Sodium caseinate (CAS) and commercial sodium alginate (CA), long chain modified alginate (LCMA) or short chain modified alginate (SCMA) were used in combination for emulsifying and stabilizing high fat (50–70%) fish oil-in-water emulsions. Physical (creaming, droplet size, viscosity and protein...

  2. Stability of Ag@SiO2 core–shell particles in conditions of photocatalytic overall water-splitting

    NARCIS (Netherlands)

    Park, Sun Young; Han, Kai; O'Neill, Devin B.; Mul, Guido

    2017-01-01

    Core–shell nanoparticles containing plasmonic metals (Ag or Au) have been frequently reported to enhance performance of photo-electrochemical (PEC) devices. However, the stability of these particles in water-splitting conditions is usually not addressed. In this study we demonstrate that Ag@SiO2

  3. Combination of sodium caseinate and succinylated alginate improved stability of high fat fish oil-in-water emulsions.

    Science.gov (United States)

    Yesiltas, Betül; Sørensen, Ann-Dorit Moltke; García-Moreno, Pedro J; Anankanbil, Sampson; Guo, Zheng; Jacobsen, Charlotte

    2018-07-30

    Sodium caseinate (CAS) and commercial sodium alginate (CA), long chain modified alginate (LCMA) or short chain modified alginate (SCMA) were used in combination for emulsifying and stabilizing high fat (50-70%) fish oil-in-water emulsions. Physical (creaming, droplet size, viscosity and protein determination) and oxidative (primary and secondary oxidation products) stabilities of the emulsions were studied during 12 days of storage. Creaming stability was higher for emulsions produced with alginates and CAS compared to emulsions prepared with only CAS. Combined use of CAS + LCMA performed better in terms of physical stability compared to emulsions produced with only CAS. However, the oxidative stability of this emulsion was inferior probably due to the presence of an unsaturated carbon chain in LCMA structure. CAS + SCMA emulsions not only showed better physical stability such as smaller droplet size, lower creaming and higher viscosity, but also had an improved oxidative stability than emulsions produced with only CAS. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Options for water-level control in developed wetlands

    Science.gov (United States)

    Kelley, J. R.; Laubhan, M. K.; Reid, F. A.; Wortham, J. S.; Fredrickson, L. H.

    1993-01-01

    Wetland habitats in the United States currently are lost at a rate of 260,000 acres/year (105,218 ha/year). Consequently, water birds concentrate in fewer and smaller areas. Such concentrations may deplete food supplies and influence behavior, physiology, and survival. Continued losses increase the importance of sound management of the remaining wetlands because water birds depend on them. Human activities modified the natural hydrology of most remaining wetlands in the conterminous United States, and such hydrologic alterations frequently reduce wetland productivity. The restoration of original wetland functions and productivity often requires the development of water distribution and discharge systems to emulate natural hydrologic regimes. Construction of levees and correct placement of control structures and water-delivery and water-discharge systems are necessary to (1) create soil and water conditions for the germination of desirable plants, (2) control nuisance vegetation, (3) promote the production of invertebrates, and (4) make foods available for wildlife that depends of wetlands (Leaflets 13.2.1 and 13.4.6). This paper provides basic guidelines for the design of wetlands that benefit wildlife. If biological considerations are not incorporated into such designs, the capability of managing wetlands for water birds is reduced and costs often are greater. Although we address the development of palustrine wetlands in migration and wintering areas, many of the discussed principles are applicable to the development of other wetland types and in other locations.

  5. Viscosity and stability of ultra-high internal phase CO2-in-water foams stabilized with surfactants and nanoparticles with or without polyelectrolytes.

    Science.gov (United States)

    Xue, Zheng; Worthen, Andrew; Qajar, Ali; Robert, Isaiah; Bryant, Steven L; Huh, Chun; Prodanović, Maša; Johnston, Keith P

    2016-01-01

    To date, relatively few examples of ultra-high internal phase supercritical CO2-in-water foams (also referred to as macroemulsions) have been observed, despite interest in applications including "waterless" hydraulic fracturing in energy production. The viscosities and stabilities of foams up to 0.98 CO2 volume fraction were investigated in terms of foam bubble size, interfacial tension, and bulk and surface viscosity. The foams were stabilized with laurylamidopropyl betaine (LAPB) surfactant and silica nanoparticles (NPs), with and without partially hydrolyzed polyacrylamide (HPAM). For foams stabilized with mixture of LAPB and NPs, fine ∼70 μm bubbles and high viscosities on the order of 100 cP at>0.90 internal phase fraction were stabilized for hours to days. The surfactant reduces interfacial tension, and thus facilitates bubble generation and decreases the capillary pressure to reduce the drainage rate of the lamella. The LAPB, which is in the cationic protonated form, also attracts anionic NPs (and anionic HPAM in systems containing polymer) to the interface. The adsorbed NPs at the interface are shown to slow down Ostwald ripening (with or without polymer added) and increase foam stability. In systems with added HPAM, the increase in the bulk and surface viscosity of the aqueous phase further decreases the lamella drainage rate and inhibits coalescence of foams. Thus, the added polymer increases the foam viscosity by threefold. Scaling law analysis shows the viscosity of 0.90 volume fraction foams is inversely proportional to the bubble size. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. PWR type reactor equipped with a primary circuit loop water level gauge

    International Nuclear Information System (INIS)

    Suzuki, Mitsuhiro.

    1990-01-01

    The time of lowering a water level to less than the position of high temperature side pipeway nozzle has been rather delayed because of the swelling of mixed water level due to heat generation of the reactor core. Further, there has been a certain restriction for the installation, maintenance and adjustment of a water level gauge since it is at a position under high radiation exposure. Then, a differential pressure type water level gauge with temperature compensation is disposed at a portion below a water level gauge of a pressurizer and between the steam generator exit plenum and the lower end of the loop seal. Further, a similar water level system is disposed to all of the loops of the primary circulation circuits. In a case that the amount of water contained in a reactor container should decreased upon occurrence of loss of coolant accidents caused by small rupture and stoppage of primary circuit pumps, lowering of the water level preceding to the lowering of the water level in the reactor core is detected to ensure the amount of water. Since they are disposed to all of the loops and ensure the excess margin, reliability for the detection of the amount of contained water can be improved by averaging time for the data of the water level and averaging the entire systems, even when there are vibrations in the fluid or pressure in the primary circuit. (N.H.)

  7. Water Wizards: School Program on Water Conservation for Third and Fourth Grade Levels.

    Science.gov (United States)

    Massachusetts State Water Resources Authority, Boston.

    Water is precious. It is also easy to take for granted. Many people recognize that water is scarce in desert areas. but it is harder to realize that places like Massachusetts could face a shortage of pure drinking water. This manual provides teachers with curriculum resources to introduce concepts of water supply and water conservation to third…

  8. Estimating the discharge for ordinary high water levels in Kansas.

    Science.gov (United States)

    2014-09-01

    The water resource design community in Kansas, including the Kansas Department of Transportation : (KDOT), is required to obtain appropriate permits for construction projects. Projects that involve stream : modification, including drainage structures...

  9. Level of faecal coliform contamination of drinking water sources and ...

    African Journals Online (AJOL)

    economic and behavioral data. Univariate and multivariate analyses were done using logistic regression models. Results: A total of 736 households participated in the study. The prevalence of positive faecal coliform at water sources in North ...

  10. REDUCING ARSENIC LEVELS IN DRINKING WATER DURING IRON REMOVAL PROCESSES

    Science.gov (United States)

    The presentation provides an overview of iron removal technology for the removal of arsenic from drinking water. The presentation is divided into several topic topics: Arsenic Chemistry, Treatment Selection, Treatment Options, Case Studies and Iron Removal Processes. Each topic i...

  11. Water potential in ponderosa pine stands of different growing-stock levels

    Science.gov (United States)

    J. M. Schmid; S. A. Mata; R. K. Watkins; M. R. Kaufmann

    1991-01-01

    Water potential was measured in five ponderosa pine (Pinus ponderosa Laws.) in each of four stands of different growing-stock levels at two locations in the Black Hills of South Dakota. Mean water potentials at dawn and midday varied significantly among growing-stock levels at one location, but differences were not consistent. Mean dawn and midday water potentials...

  12. Water-Insoluble Photosensitizer Nanocolloids Stabilized by Supramolecular Interfacial Assembly towards Photodynamic Therapy

    Science.gov (United States)

    Liu, Yamei; Ma, Kai; Jiao, Tifeng; Xing, Ruirui; Shen, Guizhi; Yan, Xuehai

    2017-02-01

    Nanoengineering of hydrophobic photosensitizers (PSs) is a promising approach for improved tumor delivery and enhanced photodynamic therapy (PDT) efficiency. A variety of delivery carriers have been developed for tumor delivery of PSs through the enhanced permeation and retention (EPR) effect. However, a high-performance PS delivery system with minimum use of carrier materials with excellent biocompatibility is highly appreciated. In this work, we utilized the spatiotemporal interfacial adhesion and assembly of supramolecular coordination to achieve the nanoengineering of water-insoluble photosensitizer Chlorin e6 (Ce6). The hydrophobic Ce6 nanoparticles are well stabilized in a aqueous medium by the interfacially-assembled film due to the coordination polymerization of tannic acid (TA) and ferric iron (Fe(III)). The resulting Ce6@TA-Fe(III) complex nanoparticles (referenced as Ce6@TA-Fe(III) NPs) significantly improves the drug loading content (~65%) and have an average size of 60 nm. The Ce6@TA-Fe(III) NPs are almost non-emissive as the aggregated states, but they can light up after intracellular internalization, which thus realizes low dark toxicity and excellent phototoxicity under laser irradiation. The Ce6@TA-Fe(III) NPs prolong blood circulation, promote tumor-selective accumulation of PSs, and enhanced antitumor efficacy in comparison to the free-carrier Ce6 in vivo evaluation.

  13. Luminescent Ag-doped In2S3 nanoparticles stabilized by mercaptoacetate in water and glycerol

    Science.gov (United States)

    Raevskaya, Alexandra E.; Ivanchenko, Maria V.; Stroyuk, Oleksandr L.; Kuchmiy, Stepan Ya.; Plyusnin, Victor F.

    2015-03-01

    Colloidal nanoparticles (NPs) of tetragonal β-In2S3 were stabilized in water and glycerol by mercaptoacetate anions. Doping of In2S3 NPs with AgI cations at the time of the synthesis imparts the NPs with the photoluminescence (PL) in the visible part of the spectrum. The doping results also in a shift of the absorption threshold and the PL band maximum to longer wavelengths proportional to the AgI content. The PL band maximum of AgI-doped In2S3 NPs can be varied from 575-580 to 760-765 nm by augmenting the silver(I) amount and the duration and temperature of the post-synthesis aging. The average radiative life-time of AgI-doped In2S3 NPs also depends on the silver(I) content and reaches the maximal value, 960 ns, at a molar Ag:In ratio of 1:4. The maximal quantum yield of stationary PL, 12 %, is observed at this Ag:In ratio as well. Deposition of a ZnS "shell" on the surface of AgI-doped In2S3 NPs results in an increase of the PL quantum yield to 30 %.

  14. Gripe water as reducing and stabilizing agent for synthesis of size controlled gold nanoparticles.

    Science.gov (United States)

    Kirubha, E; Palanisamy, P K

    2013-03-01

    Green synthesis techniques are emerging as more facile and eco-friendly approach for the synthesis of metal nanoparticles compared to chemical reduction methods. Herein we report a new approach to synthesize gold nanoparticles (AuNPs) using gripe water as a reducing as well as stabilizing agent. Good control over the size of the nanoparticles from 3.2 nm to 25 nm has been achieved with this method by simply varying the experimental conditions. The Surface Plasmon Resonance bands of tunable gold nanospheres with high monodispersity and polydispersity have been obtained by this technique and monitored using UV-Visible spectrum. The morphology and the size of these AuNPs are determined using High Resolution Transmission Electron Microscope (HR-TEM). X-Ray Diffraction (XRD) analysis confirms the crystalline nature and the phase of the AuNPs. The as-synthesized AuNPs exhibit good optical nonlinearity. The nonlinear optical studies have been carried out by Z-scan technique to demonstrate its optical limiting property. The threshold limit of the AuNPs is obtained at a input intensity of 30 mW. The nonlinear refractive index of the nanoparticles is in the order of 10(-9) cm2/W and the third-order nonlinearity is estimated to be 7 x 10(-5) esu.

  15. Synthesis of water soluble chitosan stabilized gold nanoparticles and determination of uric acid

    Science.gov (United States)

    Lanh Le, Thi; Khieu Dinh, Quang; Hoa Tran, Thai; Nguyen, Hai Phong; Le Hien Hoang, Thi; Hien Nguyen, Quoc

    2014-06-01

    Gold nanoparticles (Au-NPs) have been successfully synthesized by utilizing water soluble chitosan as reducing and stabilizing agent. The colloidal Au-NPs were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). The results showed that the colloidal Au-NPs had a plasmon absorption band with maximum wavelength in the range of 520-526 nm and the diameters were about 8-15 nm. In addition, a new Au-NPs-modified electrode was fabricated by self-assembling Au-NPs to the surface of the L-cysteine-modified glassy carbon electrode (Au-NPs/L-Cys/GCE). The Au-NPs-modified electrode showed an excellent character for electro-catalytic oxidization of uric acid (UA) in 0.1 mol L-1 phosphate buffer solution (pH 3.2). Using differential pulse anodic stripping voltammetry (DP-ASV), a high selectivity for determination of UA has been explored for the Au-NPs-modified electrode. DP-ASV peak currents of UA increased linearly with their concentration at the range of 2.0 × 10-6 to 4.0 × 10-5 mol L-1 with the detection limit of 2.7 × 10-6 mol L-1 for UA. The proposed method was applied for the detection of UA in human urine and serum samples with satisfactory results.

  16. Stability of Fluorosurfactant Adsorption on Mineral Surface for Water Removal in Tight Gas Reservoirs

    Directory of Open Access Journals (Sweden)

    Lijun You

    2015-01-01

    Full Text Available Long-term effectiveness of rock wettability alteration for water removal during gas production from tight reservoir depends on the surfactant adsorption on the pore surface of a reservoir. This paper selected typical cationic fluorosurfactant FW-134 as an example and took advantage of Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS, and atomic force microscope (AFM to investigate its adsorption stability on the rock mineral surface under the oscillation condition at high temperature for a long time. The experimental results indicate that the F element content on the sample surface increases obviously, the surface structure of fluorine-carbonization also undergoes a significant change, and the fluorine surfactant exhibits a good interfacial modification and wettability alteration ability due to its adsorption on the pore surface transforming the chemical structure of the original surface. The adsorption increases indistinctly with the concentration of over 0.05% due to a single layer adsorption structure and is mainly electrostatic adsorption because the chemical bonding between the fluorosurfactant and the rock mineral surface, the hydrogen bonding, is weak and inconspicuous.

  17. Reaction of water with a simulated high-level nuclear waste glass at 3000C, 300 bars

    International Nuclear Information System (INIS)

    McCarthy, G.J.; Scheetz, B.E.; Komarneni, S.; Smith, D.K.

    1978-01-01

    The hydrothermal stability of high-level nuclear wastes is an important consideration in establishing waste form acceptance criteria for a geological repository in basalt. A detailed examination of the stability of a typical simulated high-level waste glass and pressurized water at 300 0 C in a closed system has shown that extensive reaction occurred within a few weeks. The water acted first as a catalyst-solvent in devitrification of the glass and in dissolution, transport, and recrystallization of some of its constituents, and, second, as a reactant in forming hydrated and hydroxylated phases. This reaction with water resulted in the conversion of a solid shard of glass into a fragmented and partially dispersed mass of crystalline and noncrystalline material plus dissolved species within two weeks. The major crystalline reaction products were found to be analogs of naturally occurring minerals: (Cs,Na,Rb) 2 (UO 2 ) 2 .(Si 2 O 5 ) 3 .4H 2 O (weeksite) and a series of pyroxene-structure phases, (Na,Ca) (Fe,Zn,Ti)Si 2 O 6 (acmite, acmite--augites). Weeksite, however, is not expected to have long-term stability in the basalt environment. Much of the Na and Mo, and almost all of the B, in the original glass was identified in the product solutions. Of the elements or analogs of long-lived, hazardous radionuclides studied in this work, only Cs was observed in these solutions in substantial amounts. Although the comparatively rapid and extensive reactions at 300 0 C would appear to require that an acceptable glass would have low waste and heat loading, it is suggested that there is good potential for favorable glass--basalt--water hydrothermal interactions. Favorable interactions would mean that, in the event of a hydrothermal incident, the interaction products would be more stable than the original waste form and would remain in the immediate repository

  18. Water Hardness Level and ItAND#8217;s Health Effects

    Directory of Open Access Journals (Sweden)

    Necmettin Kocak

    2011-04-01

    Full Text Available Water hardness is a term used to define the number of ions contained in the water, especially quantity sulphate, carbonate salts of calcium and magnesium. This characteristis of water is a important quality in it’s use as drinking water, industrial water and service water. The temporary hardness level of water cames from bicarbonate salts of calcium and magnesium whereas chloride, sulphate, nitrate, phosphate, silicate salts of calcium and magnesium. In order to indicate the hardness level of water samples French Hardness Level is used in our country. There is a larger amounth of calcium and magnesium salts in hard water samples. These minerals have very important functions in the human body. In this study, the importance of hard water in terms of human health has been assessed under light of current information. The studies about the preventive role of hard water in cardiovascular diseases, cerebrovascular diseases, stroke and many types of cancer areviewed. These studies Express that higher levels of calcium and magnesium hard water provide a higher reduction in these disease. Water, which must be consumed as 2 liters per dayis very important for human life. Hard water contains a lot of the minerals that must be taker daily, especially calcium and magnesium. It’s advised that water for consumption to have medium hardness. The hardness level of water is an aesthetic quality. Thus, in populations having a taste for soft water, the effort of individuals to softer the network water provided by municipalities using different equipments, in addition to their preference of soft water in plastic or glass bottles for consumption could imply lack of benefit of hard water for population health and also bring out some risks in terms of water hygiene. [TAF Prev Med Bull 2011; 10(2.000: 187-192

  19. Well-Construction, Water-Level, and Water-Quality Data for Ground-Water Monitoring Wells for the J4 Hydrogeologic Study, Arnold Air Force Base, Tennessee

    National Research Council Canada - National Science Library

    Haugh, Connor J

    1996-01-01

    ...) in Coffee County, Tennessee. The wells ranged from 28 to 289 feet deep and were installed to provide information on subsurface lithology, aquifer characteristics, ground-water levels, and ground-water quality...

  20. Radioactivity levels in surface water of lakes around Izmir / Turkey

    International Nuclear Information System (INIS)

    Doyurum, S.; Turkozu, D. A.; Aslani, M. A. A.; Aytas, S.; Eral, M.; Kaygun, A. K.

    2006-01-01

    Radioactivity presents in surface continental waters is mainly due to the presence of radioactive elements in the earth's crust, other artificial radionuclides have appeared due to such human activities as nuclear power plants, nuclear weapons testing and manufacture and use of radioactive sources It is well known that natural radionuclides can be effective as tracers for the different processes controlling the distribution of elements among dissolved and particulate phases in aquatic systems. The detection of high radionuclide concentrations was proposed as a public health problem in several areas and consequently studies into the risks of radionuclides were started in the 2000s. Especially, these radioactive substances in groundwater are an unwanted and involuntary risk factor from natural sources, not artificial sources. These radioactive substances include uranium, radon found in uranium series, and other radioactive substances such as radium and gross alpha. Uranium present in rock, soil, and natural materials, and is found in small quantities in air, water, and food that people always contact. In this project, lake water samples were collected from three lakes around Izmir-Turkey. In surface lake water samples, pH, mV and conductivity values were measured and alkaline content was determined titrimetrically. The uranium concentrations in the lake water samples were measured using uranium analyzer. The radioactivity concentrations related to gross radium isotopes, gross-? and gross-? activities in the surface lake water were determined. The correlation among some parameters for water samples and concentrations of uranium, activity concentration of gross radium isotopes, gross alpha and gross beta radioactivity are also discussed

  1. The stability of the water column in french ponds (limousin region by the calculation of the wedderburn number

    Directory of Open Access Journals (Sweden)

    TOUCHART L.

    2014-03-01

    Full Text Available Oxygenation and biological life in lakes, reservoirs and ponds depend on the stability of the water column and on the rhythms of stratification and mixing periods. Slight thermal stratification in ponds often is regarded as the same as instability in shallow lakes. Nevertheless fetch in ponds is very short, what reduces the mixing. Wedderburn number (quotient of the buoyancy by the mixing is used to quantify the stability in shallow water bodies. We calculate it for some ponds in French region Limousin, due to original hourly water temperature measurements in all depths and wind data of Météofrance stations. First results show that very high values (above 10 are frequent in summer and spring period (during 41% of the total time of 2 336 hours from May to July in three ponds. That is why we may consider Limousin ponds as stable stratified bodies of water despite their shallowness. Continuous measurements allow to calculate the diurnal cycle and other time scales of the Wedderburn number, with periods of weakening, when air temperatures and surface water temperatures decrease, wind speed increases and when the wind blows in the same direction with the length of the pond. The most complex variable is the depth of the thermocline; a light increase of the breeze thickens the upper warm layer and strengthens the stability, but an important increase of the wind tends to destroy the stratification.

  2. Histomorphometric evaluation of the effects of various diode lasers and force levels on orthodontic mini screw stability.

    Science.gov (United States)

    Goymen, Merve; Isman, Eren; Taner, Lale; Kurkcu, Mehmet

    2015-01-01

    The purpose of this study was to evaluate the effects of different laser dose and force levels on the stability of orthodontic mini screws used for anchorage, by histomorphometric analyses. Low-level laser therapy speeds up blood flow, improves the mechanism of the revitalization processes, reduces the risk of infection, boosts metabolic activities, and accelerates the healing of the damaged tissue. Although there are many research studies about low-level laser therapy applications in a variety of areas, no investigations were found concerning mini screw stability using various laser dose levels with different force level applications. Seventeen New Zealand white rabbits were used. A total of 68 cylindrical, self-drilling orthodontic mini screws were threaded at the fibula. Experimental subjects were divided into six groups; force application was not performed in the first three groups, whereas 150 g of force was applied via nickel-titanium closed-coil springs placed between two mini screws in the other three groups. Measurements of the initial torque values (10 Ncm) were manipulated by a digital portable torque gauge. Various low-level laser doses were applied to the groups during the postoperative 10 days. After 4 weeks, bone-to-implant contact and cortical bone thickness were histomorphometrically analyzed. In the 150 g force plus 20 J/cm(2) dosage group, the highest bone-to-implant contact values were observed. (p0.05). Low-level laser therapy was noticed to induce the mini screw-bone contact area. Low-level laser therapy may be a supplementary treatment method to increase the stability of the orthodontic mini screw.

  3. Landscape stability and water management around the ancient city Jerash, Jordan

    Science.gov (United States)

    Holdridge, Genevieve; Simpson, Ian; Lichtenberger, Achim; Raja, Rubina; Kristiansen, Søren

    2017-04-01

    Reduced vulnerability to environmental fluctuations by increasing food and water security increases the resilience of a human society. In the Middle East, there is much archaeological evidence of steady developments and abrupt disasters in cities that have occurred over the millennia, while paleoenvironmental and landscape studies have provided much needed insight into the changes of a citýs surroundings. However, more in-depth urban archaeological studies of soils and sediments on-site, and the interaction of processes on- and off-site are needed to provide new information on human impact and adaptation through time in this region. The present city of Jerash is the location of one of the major Roman urban centers of the Syrian Decapolis. The city was continuously occupied from the Hellenistic period (2nd century BC) to the Umayyad period in the 8th century AD. The city is located along the Wadi Dayr, which feeds into the Zarqa River, and the area is affected by the tectonic activity of the Dead Sea Rift zone. Since the Roman period, various structures were built to manage surface water including rock-cut and plastered channels, water reservoirs and cisterns. Also, during the city's long occupation, slopes were managed by constructing terraces on- and off-site. We have examined the urban and extra-urban fluvial record along the Wadi Dayr in order to better understand urban adaptation and environmental impact of on- and off-site water and land management. By engaging an interdisciplinary approach that incorporates archaeological, paleoclimatic, and geomorphological information, our objective is to discern natural and anthropogenic influences on land and water management. In order to explore human adaptation and impact, we have examined both on- and off-site urban stratigraphy, and are currently analyzing sediments and soils at both landscape and intra-site scales. Profiles in key locations of the wadi offer insight into slope stability (upstream), site land use

  4. First-principles study of Cs/Rb co-doped FAPbI3 stability and degradation in the presence of water and oxygen

    Science.gov (United States)

    Guo, Yao; Li, Chengbo; Xue, Yuanbin; Geng, Cuihuan; Tian, Dayong

    2018-02-01

    The poor stability of organometallic halide perovskite in humid environments is one of the biggest challenges for its commercialization in light harvesting and electroluminescent displays. Understanding the atomic detail of the perovskite/water (oxygen) interface is a critical way to explore the practicability of perovskite. In this work, we report a density functional study of water and oxygen adsorption on the Cs/Rb incorporated FAPbI3 (001) surface. The role played by water and oxygen molecules has been extensively studied in the initial degradation processes, where the strong interactions between adsorbates and perovskite surfaces are confirmed. Our results show that the dopant-terminated surface was relatively more stable than PbI2-termination one. The effects of doping on the optoelectronic properties were slight at low concentrations. The calculations showed that the molecule tend to adsorb on the I-top site of the Cs-terminated surface and the Pb-top site of the PbI2 (Cs)-terminated surface. The vdW contribution on the bonding between bare surface and molecule can be observed. The degradation-induced optical absorption decrease in the visible region could be found. Water and oxygen molecule destroy the perovskite surface structures and subsequently reduce its conversion efficiency. These findings contribute molecular-level insight into the initial stage of perovskite degradation, which should be helpful to inspire new interfacial modifications to improve the stability of corresponding perovskite materials under wet conditions.

  5. Low risk of suicide and lithium in drinking water: A Danish individual-level cohort study using spatial analysis

    DEFF Research Database (Denmark)

    Knudsen, Nikoline Nygård; Schullehner, Jörg; Jørgensen, Lisbeth Flindt

    Importance of the work and objectives: Lithium occurs naturally in drinking water and may have a positive effect on mental health and suicide. In clinical practice, lithium in high therapeutic doses is used as a mood-stabilizer in the treatment of affective disorders. Previous studies performed a...... adjustment for socioeconomic factors. This study supports the growing evidence of naturally occurring lithium being protective against suicide, which, if further supported, may have implications for future public health strategies on suicide prevention.......Importance of the work and objectives: Lithium occurs naturally in drinking water and may have a positive effect on mental health and suicide. In clinical practice, lithium in high therapeutic doses is used as a mood-stabilizer in the treatment of affective disorders. Previous studies performed...... at an ecological level have found an association between lithium in drinking water and risk of suicide. The present study is the first to investigate this association at an individual level considering long-term exposure. Methodologies: The study population consisted of all 3,724,588 Danish adults (≥20 years...

  6. Chemically bonded phosphate ceramics for low-level mixed waste stabilization

    International Nuclear Information System (INIS)

    Singh, D.; Wagh, A.S.; Cunnane, J.C.; Mayberry, J.L.

    1994-01-01

    Novel chemically bonded phosphate ceramics (CBPCs) are being developed and fabricated for low-temperature stabilization and solidification of mixed waste streams which are amenable to conventional high-temperature stabilization processes due to presence of volatiles such as heavy metal chloride and fluorides and/or pyrophorics in the wastes. Phosphates of Mg, Mg-Na and Zr are being developed as candidate matrix materials. In this paper, we present the fabrication procedures of phosphate waste forms using surrogates compositions of three typical mixed wastes streams -- ash, cement sludges, and salts. The performance of the final waste forms such as compression strength, leachability of the contaminants, durability in aqueous environment were conducted. In addition, parameteric studies have been conducted to establish the optimal waste loading in a particular binder system. Based on the results, we present potential applications in the treatment of various mixed waste streams

  7. Impact of source and level of calcium fortification on the heat stability of reconstituted skim milk powder.

    Science.gov (United States)

    Vyas, H K; Tong, P S

    2004-05-01

    Calcium enrichment of food and dairy products has gained interest with the increased awareness about the importance of higher calcium intake. Calcium plays many important roles in the human body. Dairy products are an excellent source of dietary calcium, which can be further fortified with calcium salts to achieve higher calcium intake per serving. However, the addition of calcium salts can destabilize food systems unless conditions are carefully controlled. The effect of calcium fortification on the heat stability of reconstituted skim milk was evaluated, using reconstituted skim milks with 2 protein levels: 1.75 and 3.5% (wt/wt) prepared using low and high heat powders. Calcium carbonate, phosphate, lactate, and citrate were used for fortification at 0.15, 0.18, and 0.24% (wt/wt). Each sample was analyzed for solubility, heat stability, and pH. The addition of phosphate and lactate salts lowered the pH of milk, citrate did not have any major effect, and carbonate for the 1.75% protein samples increased the pH. In general, changes in solubility and heat stability were associated with changes in pH. Calcium addition decreased the solubility and heat stability. However, interestingly, the presence of carbonate salt greatly increased the heat stability for 1.75% protein samples. This is due to the neutralizing effect of calcium carbonate when it goes into solution. The results suggested that the heat stability of milk can be affected by the type of calcium salt used. This may be applied to the development of milk-based calcium enriched beverages.

  8. Natural radiation level in drinking water in Homs city

    International Nuclear Information System (INIS)

    Shweikani, R.; Raja, Gh.

    2008-11-01

    In this study, radon concentrations were measured at the sources of drinking water and in some tap water in houses in Homs County. All measurements showed that concentrations are within the international allowed limits and there is no big difference in concentration between the sources and the houses. Also total alpha/beta and radium-226 content were measured in the samples of the sources and the houses using liquid scintillation counter. All measurements showed that concentrations are within the international allowed limits. (authors)

  9. Water-level and recoverable water in storage changes, High Plains aquifer, predevelopment to 2015 and 2013–15

    Science.gov (United States)

    McGuire, Virginia L.

    2017-06-01

    The High Plains aquifer underlies 111.8 million acres (about 175,000 square miles) in parts of eight States—Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Water-level declines began in parts of the High Plains aquifer soon after the beginning of substantial irrigation with groundwater in the aquifer area (about 1950). This report presents water-level changes and change in recoverable water in storage in the High Plains aquifer from predevelopment (about 1950) to 2015 and from 2013 to 2015.The methods to calculate area-weighted, average water-level changes; change in recoverable water in storage; and total recoverable water in storage used geospatial data layers organized as rasters with a cell size of 500 meters by 500 meters, which is an area of about 62 acres. Raster datasets of water-level changes are provided for other uses.Water-level changes from predevelopment to 2015, by well, ranged from a rise of 84 feet to a decline of 234 feet. Water-level changes from 2013 to 2015, by well, ranged from a rise of 24 feet to a decline of 33 feet. The area-weighted, average water-level changes in the aquifer were an overall decline of 15.8 feet from predevelopment to 2015 and a decline of 0.6 feet from 2013 to 2015. Total recoverable water in storage in the aquifer in 2015 was about 2.91 billion acre-feet, which was a decline of about 273.2 million acre-feet since predevelopment and a decline of 10.7 million acre-feet from 2013 to 2015.

  10. Thermodynamic Stability of Actinide-Dioxide Solid Solutions and Surface Interactions with Water

    Science.gov (United States)

    Asta, Mark

    2012-02-01

    Fluorite-structured actinide dioxides are the most common forms of fuel used in nuclear energy production worldwide. This talk will provide an overview of insights into the energetics of these compounds derived through the combination of density-functional-theory-based computational studies (including Hubbard-U corrections) and calorimetric measurements. The talk will focus on two main topics: the mixing energetics of cation solid solutions, and the energetics of water adsorption on the surfaces of these compounds. For the first topic, we present results for ThO2 and UO2 based solid solutions, highlighting the roles of elastic energy arising from cation size mismatch, electrostatic interactions, and charge-transfer reactions, in governing the sign and magnitude of the mixing energetics. For water adsorption, we contrast results for surface and adsorption energies on two fluorite-structured compounds, ThO2 and CeO2, that are relevant for understanding the behavior of water on actinide oxide surfaces more generally. Through a comparison between calorimetric measurements and computational results we assess the level of accuracy achieved in the computational modeling, and suggest areas where further experimental studies would be particularly useful.

  11. Preparation and Characterization of Latex Particles as Potential Physical Shale Stabilizer in Water-Based Drilling Fluids

    Directory of Open Access Journals (Sweden)

    Junyi Liu

    2014-01-01

    Full Text Available The poly(styrene-methyl methacrylate latex particles as potential physical shale stabilizer were successfully synthesized with potassium persulfate as an initiator in isopropanol-water medium. The synthesized latex particles were characterized by Fourier transform infrared spectroscopy (FT-IR, particle size distribution measurement (PSD, transmission electron microscopy (TEM, and thermal gravimetric analysis (TGA. FT-IR and TGA analysis confirmed that the latex particles were prepared by polymerization of styrene and methyl methacrylate and maintained good thermal stability. TEM and PSD analysis indicated that the spherical latex particles possessed unimodal distribution from 80 nm to 345 nm with the D90 value of 276 nm. The factors influencing particle size distribution (PSD of latex particles were also discussed in detail. The interaction between latex particles and natural shale cores was investigated quantitatively via pore pressure transmission tests. The results indicated that the latex particles as potential physical shale stabilizer could be deformable to bridge and seal the nanopores and microfractures of shale to reduce the shale permeability and prevent pore pressure transmission. What is more, the latex particles as potential physical shale stabilizer work synergistically with chemical shale stabilizer to impart superior shale stability.

  12. Preparation and characterization of latex particles as potential physical shale stabilizer in water-based drilling fluids.

    Science.gov (United States)

    Liu, Junyi; Qiu, Zhengsong; Huang, Wei'an; Song, Dingding; Bao, Dan

    2014-01-01

    The poly(styrene-methyl methacrylate) latex particles as potential physical shale stabilizer were successfully synthesized with potassium persulfate as an initiator in isopropanol-water medium. The synthesized latex particles were characterized by Fourier transform infrared spectroscopy (FT-IR), particle size distribution measurement (PSD), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA). FT-IR and TGA analysis confirmed that the latex particles were prepared by polymerization of styrene and methyl methacrylate and maintained good thermal stability. TEM and PSD analysis indicated that the spherical latex particles possessed unimodal distribution from 80 nm to 345 nm with the D90 value of 276 nm. The factors influencing particle size distribution (PSD) of latex particles were also discussed in detail. The interaction between latex particles and natural shale cores was investigated quantitatively via pore pressure transmission tests. The results indicated that the latex particles as potential physical shale stabilizer could be deformable to bridge and seal the nanopores and microfractures of shale to reduce the shale permeability and prevent pore pressure transmission. What is more, the latex particles as potential physical shale stabilizer work synergistically with chemical shale stabilizer to impart superior shale stability.

  13. News, discussion and associative issue ownership: instability at the micro level versus stability at the macro level

    NARCIS (Netherlands)

    Kleinnijenhuis, J.; Walter, A.S.

    2014-01-01

    Associative issue ownership refers to one of the prerequisites for representative democracy-public awareness of the issue priorities of competing political parties. This article addresses the question of how the instability of associative issue ownership at the micro level of individual voters,

  14. Water-soluble metal nanoparticles stabilized by plant polyphenols for improving the catalytic properties in oxidation of alcohols

    Science.gov (United States)

    Mao, H.; Liao, Y.; Ma, J.; Zhao, S. L.; Huo, F. W.

    2015-12-01

    Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic conditions, the as-prepared BWT-Pt colloid catalyst exhibited high activity in a series of biphasic oxidation of aromatic alcohols and aliphatic alcohols. As for the cycling stability, the BWT-Pt catalyst showed no obvious decrease during the 7 cycles, revealing superior cycling stability as compared with the counterparts using PVP or PEG as the stabilizer.Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic

  15. Dual-Level Material and Psychological Assessment of Urban Water Security in a Water-Stressed Coastal City

    Directory of Open Access Journals (Sweden)

    Yajing Huang

    2015-04-01

    Full Text Available The acceleration of urbanization and industrialization has been gradually aggravating water security issues, such as water shortages, water pollution, and flooding or drought disasters and so on. Water security issues have become a great challenge to urban sustainable development. In this context, we proposed a dual-level material and psychological assessment method to assess urban water security. Psychological security coefficients were introduced in this method to combine material security and residents’ security feelings. A typical water-stressed coastal city in China (Dalian was chosen as a case study. The water security status of Dalian from 2010 to 2012 was analysed dynamically. The results indicated that the Dalian water security statuses from 2010 to 2012 were basically secure, but solutions to improve water security status and solve water resource problems are still required. This dual-level material and psychological assessment for urban water security has improved conventional material assessment through the introduction of psychological security coefficients, which can benefit decision-making for urban water planning, management and protection.

  16. Heavy metal pollution levels in water and oysters, Saccostrea ...

    African Journals Online (AJOL)

    Heavy metal (cadmium, chromium, copper, mercury, lead and zinc) concentrations in mangrove forests were investigated in water, suspended particulate matter (SPM) and oyster samples from the Mzinga Creek and Ras Dege mangrove stands, Tanzania, using Inductively Coupled Plasma–Atomic Emission Spectroscopy.

  17. Effect of Different Levels of Molasses Fed Through Drinking Water ...

    African Journals Online (AJOL)

    An experiment was conducted to evaluate the effect of molasses fed through drinking water on growth and economic performance of broiler chickens. One hundred and sixty unsexed day old chicks of Anak strain were used. They were divided into four treatment groups with each group having four replicates of ten birds per ...

  18. Determination of lead at nanogram level in water samples by ...

    African Journals Online (AJOL)

    A novel method of chemistry applicable to the determination of trace lead in water samples based on the resonance light scattering (RLS) technique has been developed. In dilute phosphoric acid medium, in the presence of a large excess of I-, Pb(II) can form [PbI4]2-, which further reacts with tetrabutyl ammonium bromide ...

  19. Socio–economic benefits and pollution levels of water resources ...

    African Journals Online (AJOL)

    user

    (in Laroo and Pawel division) that link up Gulu Municipality and. Aswa River. The springs ..... Table 3. Percentage contribution of wetland activities to monthly household income. Activities. Percentage range. Water collection. 1 – 25. Edge gardening. 25 – 50 ... avoid damage and the activity involved family labour. Burnt brick ...

  20. levels of heavy metals in gubi dam water bauchi, nigeria

    African Journals Online (AJOL)

    Ada

    A.Q. Ibrahim, Environmental Management Technology Programme Abubakar Tafawa Balewa University, ... irrigation and fishing by settlers around the dam ... The works of. Gaur et al. (2005) supports this assertion that the impact of domestic and industrial wastes contributes to high concentration of metals in water and ...

  1. levels of heavy metals in gubi dam water bauchi, nigeria

    African Journals Online (AJOL)

    Ada

    Various methods have been employed to determine heavy metals in water. Inductively coupled plasma emission spectrometer had been used in the determination ... Ni were brought into the Gulf during spring flood. ... ASSESSMENT OF HUMAN IMPACTS ON LANDUSE AND VEGETATION COVER CHANGES 31 ...

  2. Physicochemical Characteristics and Heavy Metal Levels in Water ...

    African Journals Online (AJOL)

    MICHAEL

    makes them a source of concern. Sources of heavy metals includes industrial activates (mining, oil exploration activities, manufacturing and agricultural practices), domestics and commercial practices that generates wastes, and natural factors. Metal content in rivers may vary between the water column and bed sediments.

  3. Levels of Cadmium and Lead in Water, Sediments and Selected ...

    African Journals Online (AJOL)

    Daisy Ouya

    Kenya Marine and Fisheries Research Institute, P. O. Box 81651 Mombasa, Kenya. Key words: heavy metals, cadmium, lead, water, sediment, fish, Kenya coast. Abstract—Flame absorption spectrophotometry was used to ... The pollution of marine ecosystems by heavy metals is a worldwide problem (Bryan, 1976; Ober.

  4. Socio–economic benefits and pollution levels of water resources ...

    African Journals Online (AJOL)

    The technique for socio–economic data collection was an exploratory method using transect walk along the wetland. Questionnaires and interviews were used. Domestic water sources around the wetland were sampled and analyzed according to APHA (1992). The major activities in the wetland were edge gardening, ...

  5. THE INFLUENCE OF MOLDING WATER CONTENT AND LIME CONTENT ON THE STRENGTH OF STABILIZED SOIL WITH LIME AND RICE HUSK ASH

    Directory of Open Access Journals (Sweden)

    Agus Setyo Muntohar

    2005-01-01

    Full Text Available The strength gain of stabilized soils is not only influenced by the type and proportion of the stabilizers and its curing time, but also by the water content needed to maintain the reaction. The reaction of lime – RHA with soil is pozzolanic. Hence, the process will be subjected greatly by the amount of water to react with admixtures and the proportion of the stabilizer. This paper presents the result of a laboratory study on the unconfined compressive strength (UCS of soils stabilized with lime and RHA, compacted at the OMC, and at the dry and wet side of OMC. The amount of lime required for stabilization (LRS is determined by Eades and Grim's Method. The results showed that the water content determines the UCS characteristics of unstabilized and stabilized soils. The UCS of stabilized soils decreased with increasing molding water content, but it is still higher than of the un-stabilized soils. In general, higher lime content results to a higher UCS. The maximum strength of the stabilized soil is attained at lime/RHA ratio of 1/2. The UCS of the stabilized soil increased significantly about 7 – 9 times to the un-stabilized UCS.

  6. State of the art report on boiling water reactor stability (SOAR on BWRs)

    International Nuclear Information System (INIS)

    1997-01-01

    Starting issues of this SOAR are BWR plant descriptions including peculiarities relevant to stability and the manifestation of instabilities during operation. The report continues with the characterization of instabilities from various experiments, the features and the capabilities of relevant codes and models, BWR core instrumentation and control, the stability behaviour of operating BWR plants and the regulatory approach to the stability issue. The main conclusion is that the BWR stability should not be considered as a safety issue; however R and D in specific areas is recommended

  7. Ground Water Level Measurements in Selected Boreholes Near the Site of the Proposed Repository

    Energy Technology Data Exchange (ETDEWEB)

    Page, H. Scott

    2007-11-29

    The Harry Reid Center for Environmental Studies (HRC) at the University of Nevada, Las Vegas (UNLV) acquired quarterly and continuous data on water levels from approximately 26 boreholes that comprise a periodic monitoring network (Table 1) between October 2003 and September 2007. During this period we continued to observe and analyze short and long-term ground water level trends in periodically monitored boreholes. In this report we summarize and discuss four key findings derived from analysis of water level data acquired during this period: 1. Rapid ground water level rise after storm events in Forty Mile Canyon; 2. Seismically-induced ground water level fluctuations; 3. A sample of synoptic observations and barometric influences on short term fluctuations; and 4. Long term ground water level trends observed from mid-2001 through late-2005.

  8. Water mass change in the Amazon basin estimated by multi-temporal SAR data, GRACE gravimetry and water level observations

    Science.gov (United States)

    Spiridonova, S.; Seitz, F.; Hedman, K.; Meyer, F.

    2012-04-01

    The 2007 IPCC assessment report identified the land hydrology as one of the most uncertain components of the global water cycle. Variations of continental water masses occur in several compartments (e.g. surface and soil water, snow/ice, and groundwater). Mass variations and related changes of surface water exten-sions are being observed by contemporary space and in-situ observation systems such as GRACE gravim-etry, altimetry, optical/infrared sensors, SAR/InSAR, and in-situ river gauges. In this session we will present a regional multi-sensor study in the Amazon basin. The study focuses on the quantification of variations of water mass and water surface extent caused by extreme flood and drought situations that were frequent during the last decade. PALSAR data of two extreme events was selected; once when the Amazon River was flooded (March/April 2009) and once when the region suffered from a se-vere drought (October/November 2009). The advantage of using PALSAR is that it operates in L-Band and has the possibility to penetrate through the vegetation which is essential in the Amazon basin with its dense vegetation. Time series of water level variations were obtained from two in-situ gauges at Manacapuru and Obidos as well as from Envisat satellite altimetry. Total water storage change in the whole region was given by GRACE gravimetry. First, the variation of water mass is computed numerically using GRACE. Second the water level variations obtained from the two river gauges are analyzed with respect to observation of Envisat. Third the surface water extent is estimated by extracting water masks from PALSAR image data. The water mass change is obtained by intersecting the water masks with a medium resolution digital elevation model (SRTM). More specifically, water heights along the boundary of the river body were extracted from the DEM and processed for error reduction. Then, pixel heights within the river contour were interpolated with a Delaunay triangula

  9. A microbiology-based multi-parametric approach towards assessing biological stability in drinking water distribution networks

    KAUST Repository

    Lautenschläger, Karin

    2013-06-01

    Biological stability of drinking water implies that the concentration of bacterial cells and composition of the microbial community should not change during distribution. In this study, we used a multi-parametric approach that encompasses different aspects of microbial water quality including microbial growth potential, microbial abundance, and microbial community composition, to monitor biological stability in drinking water of the non-chlorinated distribution system of Zürich. Drinking water was collected directly after treatment from the reservoir and in the network at several locations with varied average hydraulic retention times (6-52h) over a period of four months, with a single repetition two years later. Total cell concentrations (TCC) measured with flow cytometry remained remarkably stable at 9.5 (±0.6)×104cells/ml from water in the reservoir throughout most of the distribution network, and during the whole time period. Conventional microbial methods like heterotrophic plate counts, the concentration of adenosine tri-phosphate, total organic carbon and assimilable organic carbon remained also constant. Samples taken two years apart showed more than 80% similarity for the microbial communities analysed with denaturing gradient gel electrophoresis and 454 pyrosequencing. Only the two sampling locations with the longest water retention times were the exceptions and, sofar for unknown reasons, recorded a slight but significantly higher TCC (1.3(±0.1)×105cells/ml) compared to the other locations. This small change in microbial abundance detected by flow cytometry was also clearly observed in a shift in the microbial community profiles to a higher abundance of members from the Comamonadaceae (60% vs. 2% at other locations). Conventional microbial detection methods were not able to detect changes as observed with flow cytometric cell counts and microbial community analysis. Our findings demonstrate that the multi-parametric approach used provides a powerful

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

    Science.gov (United States)

    Grant, Stephen Lawrence; Tamason, Charlotte Crim; Hoque, Bilqis Amin; Jensen, Peter Kjaer Mackie

    2015-04-01

    To measure the salinity levels of common water sources in coastal Bangladesh and explore perceptions of water palatability among the local population to investigate the plausibility of linking cholera outbreaks in Bangladesh with ingestion of saline-rich cholera-infected river water. Hundred participants took part in a taste-testing experiment of water with varying levels of salinity. Salinity measurements were taken of both drinking and non-drinking water sources. Informal group discussions were conducted to gain an in-depth understanding of water sources and water uses. Salinity levels of non-drinking water sources suggest that the conditions for Vibrio cholerae survival exist 7-8 days within the local aquatic environment. However, 96% of participants in the taste-testing experiment reported that they would never drink water with salinity levels that would be conducive to V. cholerae survival. Furthermore, salinity levels of participant's drinking water sources were all well below the levels required for optimal survival of V. cholerae. Respondents explained that they preferred less salty and more aesthetically pleasing drinking water. Theoretically, V. cholerae can survive in the river systems in Bangladesh; however, water sources which have been contaminated with river water are avoided as potential drinking water sources. Furthermore, there are no physical connecting points between the river system and drinking water sources among the study population, indicating that the primary driver for cholera cases in Bangladesh is likely not through the contamination of saline-rich river water into drinking water sources. © 2015 John Wiley & Sons Ltd.

  11. nitrate-nitrogen and ammonium- nitrogen levels of some water ...

    African Journals Online (AJOL)

    NaREM

    Key words: Nitrate, ammonium, water bodies/quality, soils, Douala metropolis. ... This has initiated progressive degradation of land and other vital resources .... 2.74 35.0 30.8. Downstream. Wouri Bridge. WOU6. 04 03 59.9N. 009 41 36.3E. 7.3. 6960. 0.11 39.2 22.4. Wouri Wharf. WOU7. 04 02 27.8N. 009 40 23.9E. 7.4. 9600.

  12. Digitization and simulation realization of full range control system for steam generator water level

    International Nuclear Information System (INIS)

    Qian Hong; Ye Jianhua; Qian Fei; Li Chao

    2010-01-01

    In this paper, a full range digital control system for the steam generator water level is designed by a control scheme of single element control and three-element cascade feed-forward control, and the method to use the software module configuration is proposed to realize the water level control strategy. This control strategy is then applied in the operation of the nuclear power simulation machine. The simulation result curves indicate that the steam generator water level maintains constant at the stable operation condition, and when the load changes, the water level changes but finally maintains the constant. (authors)

  13. Water level observations in mangrove swamps during two hurricanes in Florida

    Science.gov (United States)

    Krauss, K.W.; Doyle, T.W.; Doyle, T.J.; Swarzenski, C.M.; From, A.S.; Day, Richard H.; Conner, W.H.

    2009-01-01

    Little is known about the effectiveness of mangroves in suppressing water level heights during landfall of tropical storms and hurricanes. Recent hurricane strikes along the Gulf Coast of the United States have impacted wetland integrity in some areas and hastened the need to understand how and to what degree coastal forested wetlands confer protection by reducing the height of peak water level. In recent years, U.S. Geological Survey Gulf Coast research projects in Florida have instrumented mangrove sites with continuous water level recorders. Our ad hoc network of water level recorders documented the rise, peak, and fall of water levels (?? 0.5 hr) from two hurricane events in 2004 and 2005. Reduction of peak water level heights from relatively in-line gages associated with one storm surge event indicated that mangrove wetlands can reduce water level height by as much as 9.4 cm/km inland over intact, relatively unchannelized expanses. During the other event, reductions were slightly less for mangroves along a river corridor. Estimates of water level attenuation were within the range reported in the literature but erred on the conservative side. These synoptic data from single storm events indicate that intact mangroves may support a protective role in reducing maximum water level height associated with surge.

  14. Towards risk-based drought management in the Netherlands: making water supply levels transparent to water users

    Science.gov (United States)

    Maat Judith, Ter; Marjolein, Mens; Vuren Saskia, Van; der Vat Marnix, Van

    2016-04-01

    To prepare the Dutch Delta for future droughts and water scarcity, a nation-wide 4-year project, called Delta Programme, assessed the impact of climate change and socio-economic development, and explored strategies to deal with these impacts. The Programme initiated a joint approach to water supply management with stakeholders and developed a national adaptation plan that is able to adapt to future uncertain conditions. The adaptation plan consists of a set of preferred policy pathways - sequences of possible actions and measures through time - to achieve targets while responding in a flexible manner to uncertain developments over time, allowing room to respond to new opportunities and insights. With regard to fresh water allocation, the Delta Programme stated that supplying water of sufficient quality is a shared responsibility that requires cohesive efforts among users in the main and regional water system. The national and local authorities and water users involved agreed that the water availability and, where relevant, the water quality should be as transparent and predictable as possible under normal, dry and extremely dry conditions. They therefore introduced the concept of "water supply service levels", which should describe water availability and quality that can be delivered with a certain return period, for all regions and all relevant water users in the Netherlands. The service levels form an addition to the present policy and should be decided on by 2021. At present water allocation during periods of (expected) water shortage occurs according to a prearranged ranking system (a water hierarchy scheme based on a list of priorities), if water availability drops below a critical low level. The aim is to have supply levels available that are based on the probability of occurrence and economic impact of water shortage, and that are transparent for all water users in the regional water systems and the main water system. As part of the European project

  15. Water-level data for the industrial area northwest of Delaware City, Delaware, 1993-94

    Science.gov (United States)

    Donnelly, C.A.; Hinaman, K.C.

    1996-01-01

    Water-level data for 171 wells and one surface-water site on Red Lion Creek in the industrial area northwest of Delaware City, Delaware, are presented for 1993 and 1994. Eight sets of synoptic ground- water-level measurements collected between April 1993 and September 1994, and locations and field notes for the 171 wells are presented. A hydrograph from December 19, 1993 through November 8, 1994 is presented for one surface-water site on Red Lion Creek in the industrial area. Hydrographs from October 15, 1993 through November 8, 1994 are presented for eight wells screened in the water- table aquifer. The U.S. Army Corps of Engineers collected the synoptic ground-water-level measurements. The U.S. Geological Survey collected the continuously recorded water-level data.

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

    Directory of Open Access Journals (Sweden)

    Alejandra Filippo Gonzalez Neves dos Santos

    Full Text Available Effects of water level fluctuations on body condition of Geophagus brasiliensis were studied in a 30 km² Brazilian oligotrophic reservoir. Physiological condition (K and gonadosomatic index (GSI were compared according to water level (low and high. Females' best conditions were associated to higher resources availability during high water, since gonad development did not change between low and high water. Males' condition did not change between water levels, while the highest gonad development occurred in low water. Females presented higher reproductive investment than males, which allocated most of energy for somatic development. This strategy could be a mechanism to undergo the stress caused by oligotrophic characteristics of the reservoir enhanced during low water level.

  17. Proteolytic stability in colloidal systems : interaction of proteins with the solid-water interface

    NARCIS (Netherlands)

    Maste, M.C.L.

    1996-01-01


    Proteolytic enzymes in liquid detergents suffer from lack of stability in the sense that activity diminishes with time. Although the phenomenon could be attributed to several factors, the influence of colloidal surfaces on the enzymatic stability was investigated. Besides the types of

  18. Evaluating the cement stabilization of arsenic-bearing iron wastes from drinking water treatment.

    Science.gov (United States)

    Clancy, Tara M; Snyder, Kathryn V; Reddy, Raghav; Lanzirotti, Antonio; Amrose, Susan E; Raskin, Lutgarde; Hayes, Kim F

    2015-12-30

    Cement stabilization of arsenic-bearing wastes is recommended to limit arsenic release from wastes following disposal. Such stabilization has been demonstrated to reduce the arsenic concentration in the Toxicity Characteristic Leaching Procedure (TCLP), which regulates landfill disposal of arsenic waste. However, few studies have evaluated leaching from actual wastes under conditions similar to ultimate disposal environments. In this study, land disposal in areas where flooding is likely was simulated to test arsenic release from cement stabilized arsenic-bearing iron oxide wastes. After 406 days submersed in chemically simulated rainwater, wastes. Presenting the first characterization of cement stabilized waste using μXRF, these results revealed the majority of arsenic in cement stabilized waste remained associated with iron. This distribution of arsenic differed from previous observations of calcium-arsenic solid phases when arsenic salts were stabilized with cement, illustrating that the initial waste form influences the stabilized form. Overall, cement stabilization is effective for arsenic-bearing wastes when acidic conditions can be avoided. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Stabilization and Fine Positioning to the Nanometre Level of the CLIC Main Beam Quadrupoles

    CERN Document Server

    Artoos, K; Fernandez Carmona, P; Guinchard, M; Hauviller, C; Janssens, S; Kuzmin, A; Lackner, F; Leuxe, R; Slaathaug, A

    2010-01-01

    The CLIC main beam quadrupoles need to be stabilized to 1.5 nm integrated R.M.S. displacement at 1 Hz. The choice was made to apply active stabilization with piezoelectric actuators in a rigid support with flexural guides. The advantages of this choice are the robustness against external forces and the possibility to make fast incremental nanometre positioning of the magnet with the same actuators. The study and feasibility demonstration is made in several steps from a single degree of freedom system (s.d.o.f.) with a small mass, a s.d.o.f. with a large mass, leading to the demonstration including the smallest (type 1) and largest (type 4) CLIC main beam quadrupoles. The paper discusses the choices of the position and orientation of the actuators and the tailored rigidities of the flexural hinges in the multi degree of freedom system, and the corresponding MIMO control system. The compatibility with the magnet support and micrometre alignment system is essential. The status of the study and performed tests wi...

  20. Preliminary Assessment of Water Levels in Bedrock Wells in New Hampshire, 1984 to 2007

    Science.gov (United States)

    Ayotte, Joseph D.; Kernen, Brandon M.; Wunsch, David R.; Argue, Denise M.; Bennett, Derek S.; Mack, Thomas J.

    2010-01-01

    Analysis of nearly 60,000 reported values of static water level (SWL, as depth below land surface) in bedrock wells in New Hampshire, aggregated on a yearly basis, showed an apparent deepening of SWL of about 13 ft (4 m) over the period 1984–2007. Water-level data were one-time measurements at each well and were analyzed, in part, to determine if they were suitable for analysis of trends in groundwater levels across the state. Other well characteristics, however, also have been changing over time, such as total well depth, casing length, the length of casing in bedrock, and to some extent, well yield. Analyses indicated that many of the well construction variables are significantly correlated; the apparent declines in water levels may have been caused by some of these factors. Information on changes in water use for the period was not available, although water use may be an important factor affecting water levels.

  1. Stability of coordination compounds of Ni2+ and Co2+ ions with succinic acid anion in water-ethanol solvents

    Science.gov (United States)

    Tukumova, N. V.; Dieu Thuan, Tran Thi; Usacheva, T. R.; Koryshev, N. E.; Sharnin, V. A.

    2017-04-01

    Stability constants of the coordination compounds of nickel(II) and cobalt(II) ions with succinic acid anion in water-ethanol solvents are determined via potentiometric titration at ionic strength of 0.1 and at T = 298.15 K. It is found that logβ values of monoligand complexes of these ions and succinic acid anions rise along with the content of ethanol in solution ( X EtOH = 0-0.7 mole fractions). Based on an analysis of the thermodynamic characteristics of the solvation of the reagents involved in complex formation, it is found that the increased stability of succinate complexes of nickel(II) and cobalt(II) ions in water-ethanol solvents is mainly determined by the weakening of the solvation of succinic acid anion (Y2-).

  2. Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

    Science.gov (United States)

    Wang, Mo-Zhu; Liu, Zheng-Yuan; Luo, Fang-Li; Lei, Guang-Chun; Li, Hong-Li

    2016-01-01

    Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii) and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm) of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm) were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions.

  3. Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

    Directory of Open Access Journals (Sweden)

    Mo-Zhu Wang

    Full Text Available Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions.

  4. Stability of bisphenol A (BPA) in oil-in water emulsions under riboflavin photosensitization.

    Science.gov (United States)

    Jang, Eun Yeong; Park, Chan Uk; Kim, Mi-Ja; Lee, JaeHwan

    2012-08-01

    Effects of riboflavin photosensitization on the degradation of bisphenol A (BPA) were determined in oil-in-water (O/W) emulsions containing ethylenediaminetetraacetic acid (EDTA) or sodium azide, which are a metal chelator or a singlet oxygen quencher, respectively. Also, the distribution of BPA between the continuous and dispersed phases in O/W emulsions was analyzed by high-performance liquid chromatography (HPLC). The concentration of BPA in O/W emulsions significantly decreased by 38.6% after 2 h under visible light irradiation and in the presence of riboflavin (P riboflavin photosensitization (P riboflavin photodegradation in O/W emulsions. Concentration of BPA, an endocrine disrupting chemical, was decreased significantly in oil-in-water emulsions under riboflavin and visible light irradiation. BPA in continuous aqueous phase was major target of riboflavin photosensitization. However, BPA was distributed more densely in lipid phase and more protected from riboflavin photosensitized O/W emulsions. This study can help to decrease the level of BPA in foods made of O/W emulsions containing riboflavin, which could be displayed under visible light irradiation. © 2012 Institute of Food Technologists®

  5. Tidal wetland stability in the face of human impacts and sea-level rise.

    Science.gov (United States)

    Kirwan, Matthew L; Megonigal, J Patrick

    2013-12-05

    Coastal populations and wetlands have been intertwined for centuries, whereby humans both influence and depend on the extensive ecosystem services that wetlands provide. Although coastal wetlands have long been considered vulnerable to sea-level rise, recent work has identified fascinating feedbacks between plant growth and geomorphology that allow wetlands to actively resist the deleterious effects of sea-level rise. Humans alter the strength of these feedbacks by changing the climate, nutrient inputs, sediment delivery and subsidence rates. Whether wetlands continue to survive sea-level rise depends largely on how human impacts interact with rapid sea-level rise, and socio-economic factors that influence transgression into adjacent uplands.

  6. Channel Stability and Water Quality of the Alagnak River, Southwestern Alaska

    Science.gov (United States)

    Curran, Janet H.

    2003-01-01

    , moderate in the middle reaches, and very light in the upper reaches. Maximum boat use was 137, 40, and 4 wakes per day at RK 21, 46, and 93, respectively. The mean height of the maximum wave generated in each wake was about 0.15 m (meters) at all three gaging stations. Bank erosion monitoring at 14 sites between RK 21 and 93 quantified erosion rates ranging from 0 to 1.1 m/yr (meters per year). Erodibility (based on grain-size analysis) increases in a downstream direction, as do measured erosion rates. Alagnak River banks are noncohesive and erode by grain-by-grain removal of sediment in an alternating pattern of water-driven erosion and gravitydriven erosion. Periodic surveys at bank erosion monitoring sites detected the development of a shallow underwater shelf formed by the action of wind waves and boat wakes at several sites. This shelf contains sediment eroded from the bank and redeposited adjacent to the bank; the shelf reformed as water levels changed but maintained the same wave-generated form throughout much of the season. Measurements of bank erosion processes, particularly the development of a wave-generated shelf, and visual observations suggest that boat wakes increase bank erosion rates, especially at high, exposed banks. Analysis of aerial photography and other assessments of bank erosion processes indicate that this increase in erosion rates has not altered the mechanisms of channel change, which in the past 50 years have included complex, compound channel changes and meander migration.

  7. Synthesis and stabilization of gold nanoparticles induced by denaturation and renaturation of triple helical β-glucan in water.

    Science.gov (United States)

    Jia, Xuewei; Xu, Xiaojuan; Zhang, Lina

    2013-06-10

    We report on a green procedure for the synthesis and stabilization of gold nanoparticles (AuNPs) from chlorauric acid (HAuCl4) with the use of a β-glucan known as Lentinan (LNT) without external reducing or stabilizing agents in aqueous medium. LNT adopted triple helical conformation in water, which was first denatured into single chains (s-LNT) at a high temperature of 140 °C before mixing with HAuCl4. Results from UV-vis absorption spectroscopy, transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) spectra suggested that AuCl4(-) was rapidly reduced to AuNPs by s-LNT. Moreover, the as-prepared AuNPs could be converted into nanobelt, spherical nanoparticles, and nanowire morphology simply by controlling the s-LNT concentration, reaction time, and temperature. In particular, the AuNPs nanowire was confirmed as the most stable shape in water, which was predominately ascribed to the hydrophobic cavity in the helical center of the renatured triple helical LNT (r-LNT) from s-LNT. Namely, AuNPs were entrapped in the hydrophobic cavity of r-LNT to form nanowire with an outer layer of water-soluble r-LNT, leading to stable dispersion of AuNPs. All the data demonstrated that the β-glucan of s-LNT can be used as a reducing and stabilizing agent to synthesize and disperse AuNPs in water. The whole process of reduction and stabilization was free of organic solvent and thus very safe, which is important for the potential application of AuNPs in biotechnology and biomedicine.

  8. The effect of gravity level on the stability of a Rankine cycle power system

    International Nuclear Information System (INIS)

    Schlichting, W.; Lahey, R.T.Jr.; Podowski, M.Z.

    2007-01-01

    With the initiative started by President George Bush for Nasa to return astronauts to the moon and eventually to Mars, a new means of supplying energy in space must be found, including the possible use of compact nuclear reactors and the associated phase change energy conversion systems. A key technical issue that is associated with phase change systems is their performance in space and the multiphase system instabilities that may occur. A compact boiling loop for application in microgravity is proposed. Both density-wave and pressure-drop instability models have been analyzed. The effect of geometry of the combined heated section and adiabatic riser on marginal stability of the system has been investigated at full-gravity and micro-gravity conditions. The impact of a gas-filled accumulator on the coupling between density-wave and pressure-drop-induced oscillations has been demonstrated

  9. Digital control system of a steam generator water level by LQG optimal method

    International Nuclear Information System (INIS)

    Lee, Yoon Joon

    1993-01-01

    A digital control system for the steam generator water level control is developed using LQG optimal design method. To describe the more realistic situaton, a feedwater valve actuator is assumed to be of the first order lagger and is included in the overall control system. By composing the digital control circuit in such a way that the overall control system consists of two sub-systems of feedwater station and feedback loop digital controller, the design procedure is divided into two independent steps. The feedwater station system is described in the error dynamics of an ordinary regulator system. The optimal gains are obtained by LQ method which imposes the constraints of the feedwater valve motion as well as on the output deviations. Developed also is a Kalman observer on account of the flow measurement uncertainty at low power. Then a digital controller on the feedback loop is designed so that the system maintains the same stability margins for all power ranges. The simulation results show thst the optimal digital system has a good control characteristics despite the adverse dynamics of a steam generator at low power. (Author)

  10. The life story from age 26 to 32: Rank-order stability and mean-level change.

    Science.gov (United States)

    Sengsavang, Sonia; Pratt, Michael W; Alisat, Susan; Sadler, Pamela

    2017-10-10

    In this longitudinal, mixed-methods project, the primary focus was to examine the rank-order stability and mean-level change in the life story during the period of emerging adulthood to young adulthood, while also investigating how the transition to parenthood may impact the life story. Seventy-two participants described three key life story scenes at age 26 and again at 32 (28% attrition from age 26 to 32). The narratives were coded for a range of features, including motivational themes (agency, communion), affective themes (emotional tone), an integrative meaning theme (coherent positive resolution), and a structural property (narrative complexity). Overall, there was moderate temporal stability and mean-level increase in several features of narrative identity over this key period. Positive changes in communion levels and overall emotional tone of life story scenes were especially evident for new parents at age 32. These longitudinal results suggested that adopting new social roles, in this case becoming a parent, predicted how the life story was expressed, just as they seemed to influence other levels of personality, such as traits, following the social investment principle. © 2017 Wiley Periodicals, Inc.

  11. Effect of churning temperature on water content, rheology, microstructure and stability of butter during four weeks of storage

    DEFF Research Database (Denmark)

    Rønholt, Stine; Madsen, Ann Sophie; Kirkensgaard, Jacob Judas Kain

    2014-01-01

    The effect of churning temperature (10 °C vs. 22 °C) is evaluated with respect to water content, rheology, microstructure and stability of butter produced using the batch churning method with a temperature ramp of 4 °C/min. Using pulsed-nuclear magnetic resonance, an increase in relative solid fat...... content from 44% to 49.5% was observed when decreasing the churning temperature. Due to lower solid fat content formed upon churning at high temperatures, average water droplet size significantly increased from 5.5 μm to 18.5 μm and less water could be incorporated into the butter during mixing. Using...... differential scanning calorimetry, it was observed that water addition as well as churning at low temperatures induced a transition toward more stable crystal structures, as the melting point in the high melting fraction was slightly lower for butter churned at high temperature. This did, however, not reflect...

  12. Selective retardation of perfume oil evaporation from oil-in-water emulsions stabilized by either surfactant or nanoparticles.

    Science.gov (United States)

    Binks, Bernard P; Fletcher, Paul D I; Holt, Benjamin L; Beaussoubre, Pascal; Wong, Kenneth

    2010-12-07

    We have used dynamic headspace analysis to investigate the evaporation rates of perfume oils from stirred oil-in-water emulsions into a flowing gas stream. We compare the behavior of an oil of low water solubility (limonene) and one of high water solubility (benzyl acetate). It is shown how the evaporation of an oil of low water solubility is selectively retarded and how the retardation effect depends on the oil volume fraction in the emulsion. We compare how the evaporation retardation depends on the nature of the adsorbed film stabilizing the emulsion. Surfactant films are less effective than adsorbed films of nanoparticles, and the retardation can be further enhanced by compression of the adsorbed nanoparticle films by preshrinking the emulsion drops.

  13. Crack-free yttria stabilized zirconia thin films by aerosol assisted chemical vapor deposition: Influence of water and carrier gas

    Energy Technology Data Exchange (ETDEWEB)

    Schlupp, M.V.F., E-mail: Meike.Schlupp@mat.ethz.ch [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); Binder, S.; Martynczuk, J.; Prestat, M. [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); Gauckler, L.J. [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2012-11-01

    Yttria stabilized zirconia thin films are deposited on silicon single crystal substrates by aerosol assisted chemical vapor deposition from precursor solutions of zirconium and yttrium 2,4-pentanedionate in ethanol. Continuous films are obtained using pure oxygen, pure nitrogen, or mixtures of both as carrier gas. In the simultaneous presence of water and oxygen, crack formation is observed for films deposited at intermediate substrate temperatures (450 Degree-Sign C), while those deposited at low (300 Degree-Sign C) and high (600 Degree-Sign C) temperatures remain crack-free. Crack-free films can be deposited at 450 Degree-Sign C in a water-free setting, or in the presence of water using pure nitrogen as carrier gas. The addition of water to the precursor solutions also significantly reduces film growth rates. - Highlights: Black-Right-Pointing-Pointer Thin film deposition by aerosol assisted chemical vapor deposition (AA-CVD) Black-Right-Pointing-Pointer Yttria stabilized zirconia (YSZ) thin films deposited between 300 Degree-Sign C and 600 Degree-Sign C Black-Right-Pointing-Pointer Water decreases growth rates and leads to crack formation in AA-CVD of YSZ. Black-Right-Pointing-Pointer Crack-free YSZ thin films deposited using oxygen and/or nitrogen as carrier gas Black-Right-Pointing-Pointer YSZ thin films deposited by AA-CVD show low shrinkage on annealing at 1000 Degree-Sign C.

  14. Nitrate and ammonium levels of some water bodies and their ...

    African Journals Online (AJOL)

    The present study examined the nitrate (NO3-) and ammonium (NH4+) levels of Rivers Wouri and Dibamba and some streams that feed them. The interaction of NO3- and NH4+ with some soil properties was also investigated. It was necessitated by the usage of these rivers for livelihood, despite the deposition of discharges ...

  15. Synthesis and Use of Amphoteric Carboxymethylcellulose Graft Copolymers in the Environmentally-acceptable Water-based DrillingFluids as a Water-sensitive Shale Stabilizer

    Directory of Open Access Journals (Sweden)

    M. Abdollahi

    2009-12-01

    Full Text Available Water soluble amphoteric graft copolymers of polysaccharide were synthesized via grafting of cationic monomer onto the sodium carboxymethylcellulose (CMC( and then used as a shale stabilizer in the water-based drilling fluids. Accordingly, five types of CMC-graft copolymers with different ratios of acrylamide AM( and diallyldimethylammonium chloride DADMAC( were synthesized. Grafting of monomer(s( onto the CMC was verified by FT-IR spectroscopy. Results showed that grafting percentage is strongly affected by the monomer type as well as the weight ratio of monomers. Synthesized CMC-graft copolymers were used in the formulation of water-based drilling fluid. Drilling fluid was then subjected to the rheological, fluid loss and shale recovery tests. It was found that ability of CMC in the shale stability enhances by grafting of cationic monomer onto CMC. Fluid loss is also controlled in the acceptable region in the presence of CMC-graft copolymers. Among graft copolymers, CMC-grafted with pure cationic monomer exhibited higher efficiency in the fluid loss control and more important in the shale stability.

  16. Water level affects availability of optimal feeding habitats for threatened migratory waterbirds.

    Science.gov (United States)

    Aharon-Rotman, Yaara; McEvoy, John; Zhaoju, Zheng; Yu, Hui; Wang, Xin; Si, Yali; Xu, Zhenggang; Yuan, Zeng; Jeong, Wooseog; Cao, Lei; Fox, Anthony D

    2017-12-01

    Extensive ephemeral wetlands at Poyang Lake, created by dramatic seasonal changes in water level, constitute the main wintering site for migratory Anatidae in China. Reductions in wetland area during the last 15 years have led to proposals to build a Poyang Dam to retain high winter water levels within the lake. Changing the natural hydrological system will affect waterbirds dependent on water level changes for food availability and accessibility. We tracked two goose species with different feeding behaviors (greater white-fronted geese Anser albifrons [grazing species] and swan geese Anser cygnoides [tuber-feeding species]) during two winters with contrasting water levels (continuous recession in 2015; sustained high water in 2016, similar to those predicted post-Poyang Dam), investigating the effects of water level change on their habitat selection based on vegetation and elevation. In 2015, white-fronted geese extensively exploited sequentially created mudflats, feeding on short nutritious graminoid swards, while swan geese excavated substrates along the water edge for tubers. This critical dynamic ecotone successively exposes subaquatic food and supports early-stage graminoid growth during water level recession. During sustained high water levels in 2016, both species selected mudflats, but also to a greater degree of habitats with longer established seasonal graminoid swards because access to tubers and new graminoid growth was restricted under high-water conditions. Longer established graminoid swards offer less energetically profitable forage for both species. Substantial reduction in suitable habitat and confinement to less profitable forage by higher water levels is likely to reduce the ability of geese to accumulate sufficient fat stores for migration, with potential carryover effects on subsequent survival and reproduction. Our results suggest that high water levels in Poyang Lake should be retained during summer, but permitted to gradually recede

  17. Recent Changes in Land Water Storage and Its Contribution to Sea Level Variations

    Science.gov (United States)

    Wada, Yoshihide; Reager, John T.; Chao, Benjamin F.; Wang, Jida; Lo, Min-Hui; Song, Chunqiao; Li, Yuwen; Gardner, Alex S.

    2016-01-01

    Sea level rise is generally attributed to increased ocean heat content and increased rates glacier and ice melt. However, human transformations of Earth's surface have impacted water exchange between land, atmosphere, and ocean, ultimately affecting global sea level variations. Impoundment of water in reservoirs and artificial lakes has reduced the outflow of water to the sea, while river runoff has increased due to groundwater mining, wetland and endorheic lake storage losses, and deforestation. In addition, climate-driven changes in land water stores can have a large impact on global sea level variations over decadal timescales. Here, we review each component of negative and positive land water contribution separately in order to highlight and understand recent changes in land water contribution to sea level variations.

  18. Ground-water levels in Wyoming, January 1986 through September 1995

    Science.gov (United States)

    Mason, J.P.; Green, S.L.

    1996-01-01

    Water levels were measured in a network of 81 observation wells in Wyoming as of September 1995. The wells are located mainly in areas where ground water is used in large quantities for irrigation or municipal purposes. Water-level data were collected at 74 of the 81 observation wells by Wyoming State Engineer personnel; data at theremaining 7 wells were collected by the U.S. Geological Survey. This report contains hydrographs for 81 observation wells showing water-level fluctuations from January 1986 through September 1995. Included in the report are maps showing location of the observation wells and tableslisting observation-well depths, use of water, principal geologic source, records available, and highest and lowest water levels for the period ofrecord.

  19. The Water Footprint as an indicator of environmental sustainability in water use at the river basin level.

    Science.gov (United States)

    Pellicer-Martínez, Francisco; Martínez-Paz, José Miguel

    2016-11-15

    One of the main challenges in water management is to determine how the current water use can condition its availability to future generations and hence its sustainability. This study proposes the use of the Water Footprint (WF) indicator to assess the environmental sustainability in water resources management at the river basin level. The current study presents the methodology developed and applies it to a case study. The WF is a relatively new indicator that measures the total volume of freshwater that is used as a production factor. Its application is ever growing in the evaluation of water use in production processes. The calculation of the WF involves water resources (blue), precipitation stored in the soil (green) and pollution (grey). It provides a comprehensive assessment of the environmental sustainability of water use in a river basin. The methodology is based upon the simulation of the anthropised water cycle, which is conducted by combining a hydrological model and a decision support system. The methodology allows the assessment of the environmental sustainability of water management at different levels, and/or ex-ante analysis of how the decisions made in water planning process affect sustainability. The sustainability study was carried out in the Segura River Basin (SRB) in South-eastern Spain. The SRB is among the most complex basins in Europe, given its special peculiarities: competition for the use, overexploitation of aquifers, pollution, alternative sources, among others. The results indicate that blue water use is not sustainable due to the generalised overexploitation of aquifers. They also reveal that surface water pollution, which is not sustainable, is mainly caused by phosphate concentrations. The assessment of future scenarios reveals that these problems will worsen if no additional measures are implemented, and therefore the water management in the SRB is environmentally unsustainable in both the short- and medium-term. Copyright © 2016

  20. The effect of hydraulic roughness on design water levels in river models

    NARCIS (Netherlands)

    Warmink, Jord Jurriaan; Straatsma, M.; Huthoff, Freek; Klijn, F.; Schweckendiek, T.

    2013-01-01

    Accurate estimates of design water levels are essential, because they determine the required dimensions of the flood defences. Hydrodynamic models are used for the prediction of flood water levels to support flood safety and are often applied in a deterministic way. However, the modelling of river

  1. Effect of different irrigation water level on cotton yield and yield ...

    African Journals Online (AJOL)

    Effects of different water level on yield and yield components of the drip irrigated cotton were evaluated in Amik Plain in the East Mediterranean Region of Turkey. Four levels of irrigation water were tested in 2003 and 2004. Treatments were 25 (I25), 50 (I50), 75% (I75) of the full irrigation treatment (I100) which received ...

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

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; Vijith, V.

    Using water-level data collected at six locations during March–April 2003 in the main channel of the Mandovi estuary, one of the 50 odd estuaries on the west coast of India, we describe the nature of variability of water level in the estuary...

  3. Oxidative stability and ignition quality of algae derived methyl esters containing varying levels of methyl eicosapentaenoate and methyl docosahexaenoate

    Science.gov (United States)

    Bucy, Harrison

    Microalgae is currently receiving strong consideration as a potential biofuel feedstock to help meet the advanced biofuels mandate of the 2007 Energy Independence and Security Act because of its theoretically high yield (gallons/acre/year) in comparison to current terrestrial feedstocks. Additionally, microalgae also do not compete with food and can be cultivated with wastewater on non-arable land. Microalgae lipids can be converted into a variety of biofuels including fatty acid methyl esters (e.g. FAME biodiesel), renewable diesel, renewable gasoline, or jet fuel. For microalgae derived FAME, the fuel properties will be directly related to the fatty acid composition of the lipids produced by the given microalgae strain. Several microalgae species under consideration for wide scale cultivation, such as Nannochloropsis, produce lipids with fatty acid compositions containing substantially higher quantities of long chainpolyunsaturated fatty acids (LC-PUFA) in comparison to terrestrial feedstocks. It is expected that increased levels of LC-PUFA will be problematic in terms of meeting all of the current ASTM specifications for biodiesel. For example, it is known that oxidative stability and cetane number decrease with increasing levels of LC-PUFA. However, these same LC-PUFA fatty acids, such as eicosapentaenoic acid (EPA: C20:5) and docosahexaenoic acid (DHA: C22:6) are known to have high nutritional value thereby making separation of these compounds economically attractive. Given the uncertainty in the future value of these LC-PUFA compounds and the economic viability of the separation process, the goal of this study was to examine the oxidative stability and ignition quality of algae-based FAME with varying levels of EPA and DHA removal. Oxidative stability tests were conducted at a temperature of 110°C and airflow of 10 L/h using a Metrohm 743 Rancimat with automatic induction period determination following the EN 14112 Method from the ASTM D6751 and EN 14214

  4. Stability of the bond between two resin cements and an yttria-stabilized zirconia ceramic after six months of aging in water.

    Science.gov (United States)

    da Silva, Eduardo M; Miragaya, Luciana; Sabrosa, Carlos Eduardo; Maia, Lucianne C

    2014-09-01

    The behavior of the luting cement and the cementation protocol are essential in the clinical success of ceramic restorations. The purpose of this study was to evaluate the bond stability of 2 resin cements and a yttria-stabilized tetragonal polycrystalline zirconia (Y-TZP) ceramic submitted to 2 surface treatments. Sixty plates of a Y-TZP ceramic were assigned to 3 groups according to the surface treatments: control, as sintered surface; methacryloxydecyl dihydrogen phosphate (MDP), coated with an MDP-based primer, and tribochemical silica-coating (TSC), coated with tribochemical silica. The plates of each group were further divided into 2 subgroups according to the resin cement as follows: RelyX adhesive resin cement (conventional) and RelyX Unicem (self-adhesive). Cylinders of resin cements (∅=0.75 mm × 0.5 mm in height) were built up on the ceramic surfaces, and the plates stored in distilled water at 37°C for either 24 hours or 6 months before being submitted to a microshear bond strength test. The data were submitted to 3-way ANOVA and the Tukey honestly significant difference test (α=.05). Three-way ANOVA showed statistical significance for the 3 independent factors: resin cement, surface treatment, and period of water immersion (Presin cement applied on ceramic surfaces treated with TSC, the microshear bond strength of all the other groups decreased after 6 months of aging in water. The microshear bond strength decreased most in the control groups (-81.5% for ARC and -93.1% for Unicem). In the group treated with TSC, the microshear bond strength for Unicem decreased by 54.8% and in that treated with MDP-based primer by -42.5%. In the group treated with MDP-based primer, the microshear bond strength for RelyX ARC decreased by -52.8%. Irrespective of surface treatments, self-adhesive resin cement was not able to maintain the bond to Y-TZP ceramic after 6 months of aging in water. Copyright © 2014 Editorial Council for the Journal of Prosthetic

  5. Nonstoichiometry and stability in water of undoped SrCeO3

    Directory of Open Access Journals (Sweden)

    Jurado, J. R.

    2003-10-01

    Full Text Available Strontium cerate is the parent phase of an important class of proton-conducting perovskites with various potential technological applications. Phase formation and structure of SrCeO3 with Sr:Ce nonstoichiometry have been investigated for the series, Sr1±xCeO3±δ (0.98 ≤ x ≤ 1.04. Analyses by EPMA (electron probe micro analysis and X-ray diffraction (XRD indicate that, for samples sintered at 1350°C, the main phase is Sr-rich for all x. The accommodation of excess SrO in the bulk phase and/or intergranular regions is discussed. The stability of nominally stoichiometric SrCeO3 was examined in an atmosphere of high water vapour partial pressure (pH2O for 2 hours, degrading to Sr(OH2.H2O and CeO2 for pH2O ≥ 3.6atm.La fase SrCeO3 da origen a una importante familia de perovskitas conductoras protónicas con potenciales aplicaciones tecnológicas. En este trabajo se estudia la formación de la fase y la estructura de SrCeO3 con la relación Sr:Ce no estequiométrica para la serie Sr1±xCeO3±δ (0.98 ≤ x ≤ 1.04. Los análisis por microsonda (EPMA y difracción de rayos X (DRX indican que en las muestras sinterizadas a 1350°C, la fase principal es rica en estroncio para todo valor de x. Se discute la posible ubicación del exceso de SrO tanto en la región intergranular como en el propio grano. También se examina la estabilidad de la composición con estequiometría nominal SrCeO3 en una atmosfera con una alta presión de vapor de agua (pH2O, observándose que la degradación a Sr(OH2.H2O y CeO2 ocurre a pH2O ≥ 3.6atm (expuesto durante 2 horas.

  6. Observations and estimates of wave-driven water level extremes at the Marshall Islands

    Science.gov (United States)

    Merrifield, M. A.; Becker, J. M.; Ford, M.; Yao, Y.

    2014-10-01

    Wave-driven extreme water levels are examined for coastlines protected by fringing reefs using field observations obtained in the Republic of the Marshall Islands. The 2% exceedence water level near the shoreline due to waves is estimated empirically for the study sites from breaking wave height at the outer reef and by combining separate contributions from setup, sea and swell, and infragravity waves, which are estimated based on breaking wave height and water level over the reef flat. Although each component exhibits a tidal dependence, they sum to yield a 2% exceedence level that does not. A hindcast based on the breaking wave height parameterization is used to assess factors leading to flooding at Roi-Namur caused by an energetic swell event during December 2008. Extreme water levels similar to December 2008 are projected to increase significantly with rising sea level as more wave and tide events combine to exceed inundation threshold levels.

  7. Testing and use of radar water level sensors by the U.S. Geological Survey

    Science.gov (United States)

    Fulford, Janice M.

    2016-01-01

    The United States Geological Survey uses water-level (or stage) measurements to compute streamflow at over 8000 stream gaging stations located throughout the United States (waterwatch.usgs.gov, 2016). Streamflow (or discharge) is computed at five minute to hourly intervals from a relationship between water level and discharge that is uniquely determined for each station. The discharges are posted hourly to WaterWatch (waterwatch. usgs.gov) and are used by water managers to issue flood warnings and manage water supply and by other users of water information to make decisions. The accuracy of the water-level measurement is vital to the accuracy of the computed discharge. Because of the importance of water-level measurements, USGS has an accuracy policy of 0.02 ft or 0.2 percent of reading (whichever is larger) (Sauer and Turnipseed, 2010). Older technologies, such as float and shaft-encoder systems, bubbler systems and submersible pressure sensors, provide the needed accuracy but often require extensive construction to install and are prone to malfunctioning and damage from floating debris and sediment. No stilling wells or orifice lines need to be constructed for radar installations. During the last decade testing by the USGS Hydrologic Instrumentation Facility(HIF) found that radar water-level sensors can provide the needed accuracy for water-level measurements and because the sensor can be easily attached to bridges, reduce the construction required for installation. Additionally, the non-contact sensing of water level minimizes or eliminates damage and fouling from floating debris and sediment. This article is a brief summary of the testing efforts by the USGS HIF and field experiences with models of radar water-level sensors in streamflow measurement applications. Any use of trade names in this article is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  8. Water security at local government level. What do people think it means in eThekwini?

    CSIR Research Space (South Africa)

    Meissner, Richard

    2017-12-01

    Full Text Available Local level Water security is an enabler for livelihood security (including food security, better opportunities for people and job security) An overemphasis on the economic benefits of water security may overshadow ethical implications Our water... insecurity. The future is now Water security can be improved through good foresight and planning, but there is a dilemma in that government is not good at this. Local, national and geographically wide areas linked to climatic conditions...

  9. Sleep-wake stability in narcolepsy patients with normal, low and unmeasurable hypocretin levels.

    Science.gov (United States)

    Hansen, Mathias Hvidtfelt; Kornum, Birgitte Rahbek; Jennum, Poul

    2017-06-01

    To compare diurnal and nocturnal electrophysiological data from narcolepsy patients with undetectable (110 pg/mL) cerebrospinal fluid (CSF) hypocretin-1 levels. A total of 109 narcolepsy patients and 37 controls were studied; all had available CSF hypocretin-1 measurements. The sleep laboratory studies were conducted between 2008 and 2014. The study retrospectively examined measurements of sleep stage transitions in diurnal and nocturnal continuous polysomnography. The percentage distribution of time awake and rapid eye movement (REM) sleep, and the occurrence of sleep onset REM (SOREM) in the nocturnal polysomnography were also measured. Participants with undetectable hypocretin-1 levels had significantly higher frequencies of transitions than controls and those with normal hypocretin-1 levels. Participants with low hypocretin-1 levels showed more transitions than controls and, in some cases, also more than those with normal hypocretin-1. Participants with normal hypocretin-1 failed to show any significant difference from the controls, except in the overall diurnal transitions. Undetectable hypocretin-1 levels in particular, but also low hypocretin-1 levels, were associated with a less stable phenotype featuring more sleep state transitions and SOREM episodes. In addition, there was a distinction between nocturnal and diurnal REM sleep in hypocretin-deficient participants, expressed as increased diurnal REM sleep, which was not reflected in nocturnal sleep. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Implant stability and marginal bone level of microgrooved zirconia dental implants: A 3-month experimental study on dogs

    Directory of Open Access Journals (Sweden)

    Delgado-Ruíz Rafael Arcesio

    2014-01-01

    Full Text Available Background/Aim. The modification of implant surfaces could affect mechanical implant stability as well as dynamics and quality of peri-implant bone healing. The aim of this 3-month experimental study in dogs was to investigate implant stability, marginal bone levels and bone tissue response to zirconia dental implants with two laser-micro-grooved intraosseous surfaces in comparison with nongrooved sandblasted zirconia and sandblasted, high-temperature etched titanium implants. Methods. Implant surface characterization was performed using optical interferometric profilometry and energy dispersive X-ray spectroscopy. A total of 96 implants (4 mm in diameter and 10 mm in length were inserted randomly in both sides of the lower jaw of 12 Fox Hound dogs divided into groups of 24 each: the control (titanium, the group A (sandblasted zirconia, the group B (sandblasted zirconia plus microgrooved neck and the group C (sandblasted zirconia plus all microgrooved. All the implants were immediately loaded. Insertion torque, periotest values, radiographic crestal bone level and removal torque were recorded during the 3-month follow-up. Qualitative scanning electon micro-scope (SEM analysis of the bone-implant interfaces of each group was performed. Results. Insertion torque values were higher in the group C and control implants (p the control > the group B > the group A (p the control > the group B > the group A (p < 0.05. SEM showed that implant surfaces of the groups B and C had an extra bone growth inside the microgrooves that corresponded to the shape and direction of the microgrooves. Conclusion. The addition of micro-grooves to the entire intraosseous surface of zirconia dental implants enhances primary and secondary implant stability, promotes bone tissue ingrowth and preserves crestal bone levels.

  11. Stability and change in physical activity levels: a literature rewiew based in the concept and values of tracking

    Directory of Open Access Journals (Sweden)

    Catarina Margarida da Silva Vasques

    2005-12-01

    Full Text Available The main purposes of this paper is to review the concepts of stability and tracking, as well as the main results from longitudinal studies focusing on physical activity. We explain the different meanings of stability: structural, normative or covariance, level or means, and ipsative. We also look at tracking issues, its different meanings and ways of computation. The main results from physical activity studies do show that, in general, stability varies from low to moderate values. These results challenge researchers from different fields of study, from epidemiologists to physical education teachers. RESUMO Esta revisão pretende efectuar uma abordagem aos conceitos de estabilidade e tracking, bem como resumir os principais resultados de estudos longitudinais sobre estabilidade da actividade física. Faz-se a distinção entre os diferentes tipos de estabilidade: estrutural, normativa ou da covariância, de nível ou das médias, e ipsativa. Aborda-se a problemática do tracking, da sua multiplicidade de significações e operacionalizações. Os principais resultados sobre a estabilidade da actividade física salientam, que na generalidade, os seus valores são baixos a moderados. Este quadro genérico coloca desafios à investigação de inúmeros pesquisadores, desde epidemiologistas a professores de educação física.

  12. Reactor vessel water level estimation during severe accidents using cascaded fuzzy neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Yeong; Yoo, Kwae Hwan; Choi, Geon Pil; Back, Ju Hyun; Na, Man Gyun [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of)

    2016-06-15

    Global concern and interest in the safety of nuclear power plants have increased considerably since the Fukushima accident. In the event of a severe accident, the reactor vessel water level cannot be measured. The reactor vessel water level has a direct impact on confirming the safety of reactor core cooling. However, in the event of a severe accident, it may be possible to estimate the reactor vessel water level by employing other information. The cascaded fuzzy neural network (CFNN) model can be used to estimate the reactor vessel water level through the process of repeatedly adding fuzzy neural networks. The developed CFNN model was found to be sufficiently accurate for estimating the reactor vessel water level when the sensor performance had deteriorated. Therefore, the developed CFNN model can help provide effective information to operators in the event of a severe accident.

  13. Identifying sequential substrate binding at the single-molecule level by enzyme mechanical stabilization.

    Science.gov (United States)

    Rivas-Pardo, Jaime Andrés; Alegre-Cebollada, Jorge; Ramírez-Sarmiento, César A; Fernandez, Julio M; Guixé, Victoria

    2015-01-01

    Enzyme-substrate binding is a dynamic process intimately coupled to protein structural changes, which in turn changes the unfolding energy landscape. By the use of single-molecule force spectroscopy (SMFS), we characterize the open-to-closed conformational transition experienced by the hyperthermophilic adenine diphosphate (ADP)-dependent glucokinase from Thermococcus litoralis triggered by the sequential binding of substrates. In the absence of substrates, the mechanical unfolding of TlGK shows an intermediate 1, which is stabilized in the presence of Mg·ADP(-), the first substrate to bind to the enzyme. However, in the presence of this substrate, an additional unfolding event is observed, intermediate 1*. Finally, in the presence of both substrates, the unfolding force of intermediates 1 and 1* increases as a consequence of the domain closure. These results show that SMFS can be used as a powerful experimental tool to investigate binding mechanisms of different enzymes with more than one ligand, expanding the repertoire of protocols traditionally used in enzymology.

  14. Tree-level stability without spacetime fermions: novel examples in string theory

    International Nuclear Information System (INIS)

    Israel, Dan; Niarchos, Vasilis

    2007-01-01

    Is perturbative stability intimately tied with the existence of spacetime fermions in string theory in more than two dimensions? Type 0'B string theory in ten-dimensional flat space is a rare example of a non-tachyonic, non-supersymmetric string theory with a purely bosonic closed string spectrum. However, all known type 0' constructions exhibit massless NSNS tadpoles signaling the fact that we are not expanding around a true vacuum of the theory. In this note, we are searching for perturbatively stable examples of type 0' string theory without massless tadpoles in backgrounds with a spatially varying dilaton. We present two examples with this property in non-critical string theories that exhibit four- and six-dimensional Poincare invariance. We discuss the D-branes that can be embedded in this context and the type of gauge theories that can be constructed in this manner. We also comment on the embedding of these non-critical models in critical string theories and their holographic (Little String Theory) interpretation and propose a general conjecture for the role of asymptotic supersymmetry in perturbative string theory

  15. First-year evaluation of low-level waste-management stabilization techniques

    International Nuclear Information System (INIS)

    Cox, G.R.

    1981-12-01

    The first year of observation for effectiveness of biobarriers and herbicides in revegetation efforts demonstrated that certain practices will result in successful site stabilization: proper orientation of burial trench to reduce erosion; utilization of mulches to conserve moisture; seeding mixed perennial or annual grass species at the proper time for optimization of establishment and growth; and applying 2,4-D amine/Dicamba selective herbicide at the optimum time for enhancement of disirable grasses and reduction of competition from other species. The ultimate success or failure of a revegetation operation depends in part on the availability of equipment and manpower, weather conditions, and engineering feasibility. The data indicated that perennial grasses offered advantages over annual grasses and that the 2,4-D amine/Dicamba herbicide spray program was successful and should be expanded for next year. However, programmatic decisions should not be based on the data for 1 year, but should be based on data gathered over the full 3 years of the project

  16. Stabilization energies of charged multiexciton complexes calculated at configuration interaction level

    Science.gov (United States)

    Corni, S.; Braskén, M.; Lindberg, M.; Olsen, J.; Sundholm, D.

    2003-06-01

    Recombination and stabilization energies of multiexcitons confined in positively and negatively charged semiconductor InGaAs/GaAs quantum dot (QD) samples have been studied by employing large-scale configuration interaction (CI) calculations. The CI calculations show that at most six electrons or two holes can be confined in the QD. Multiply charged multiexciton complexes with up to five excess electrons or two excess holes are also found to be stable, even when a few electron-hole pairs are present in the QD. The chemical potential functions for charged QD samples do not possess the pronounced stepped form as obtained for the corresponding neutral multiexciton complexes. The negatively and the positively charged excitons (negative and positive trions) lie lower in energy as compared to a neutral exciton and a single non-interacting charge carrier in the lowest single-particle state of another quantum dot. The other charged multiexciton complexes studied are not confined with respect to the corresponding neutral multiexciton and a non-interacting charge carrier. To include the contributions from the heavy-hole light-hole (HH-LH) coupling, a perturbative treatment of the band-mixing effects was implemented. The perturbation-theory calculations show that the HH-LH coupling does not shift the energies in the present InGaAs/GaAs QD sample.

  17. Urban stormwater – greywater management system for sustainable urban water management at sub-watershed level

    Directory of Open Access Journals (Sweden)

    Arora Amarpreet Singh

    2017-01-01

    Full Text Available Urban water management involves urban water supply (import, treatment and distribution of water, urban wastewater management (collection, treatment and disposal of urban sewage and urban storm water management. Declining groundwater tables, polluted and declining sources of water, water scarcity in urban areas, unsatisfactory urban water supply and sanitation situation, pollution of receiving water bodies (including the ground water, and urban floods have become the concerns and issues of sustainable urban water management. This paper proposes a model for urban stormwater and sewage management which addresses these concerns and issues of sustainable urban water management. This model proposes segregation of the sewage into black water and greywater, and urban sub-watershed level stormwater-greywater management systems. During dry weather this system will be handling only the greywater and making the latter available as reclaimed water for reuse in place of the fresh water supply. During wet weather, the system will be taking care of (collection and treatment both the storm water and the greywater, and the excess of the treated water will be disposed off through groundwater recharging. Application of this model in the Patiala city, Punjab, INDIA for selected urban sub-watersheds has been tried. Information and background data required for the conceptualization and design of the sub-watershed level urban stormwater-greywater management system was collected and the system has been designed for one of the sub-watersheds in the Patiala city. In this paper, the model for sustainable urban water management and the design of the Sub-watershed level Urban Stormwater-Greywater Management System are described.

  18. Urban stormwater - greywater management system for sustainable urban water management at sub-watershed level

    Science.gov (United States)

    Singh Arora, Amarpreet

    2017-11-01

    Urban water management involves urban water supply (import, treatment and distribution of water), urban wastewater management (collection, treatment and disposal of urban sewage) and urban storm water management. Declining groundwater tables, polluted and declining sources of water, water scarcity in urban areas, unsatisfactory urban water supply and sanitation situation, pollution of receiving water bodies (including the ground water), and urban floods have become the concerns and issues of sustainable urban water management. This paper proposes a model for urban stormwater and sewage management which addresses these concerns and issues of sustainable urban water management. This model proposes segregation of the sewage into black water and greywater, and urban sub-watershed level stormwater-greywater management systems. During dry weather this system will be handling only the greywater and making the latter available as reclaimed water for reuse in place of the fresh water supply. During wet weather, the system will be taking care of (collection and treatment) both the storm water and the greywater, and the excess of the treated water will be disposed off through groundwater recharging. Application of this model in the Patiala city, Punjab, INDIA for selected urban sub-watersheds has been tried. Information and background data required for the conceptualization and design of the sub-watershed level urban stormwater-greywater management system was collected and the system has been designed for one of the sub-watersheds in the Patiala city. In this paper, the model for sustainable urban water management and the design of the Sub-watershed level Urban Stormwater-Greywater Management System are described.

  19. Water level determination for transportation projects : mean high water manual, final report, November 2009.

    Science.gov (United States)

    2009-11-01

    To ensure proficient network management and safe usage of navigable waterways especially in waters that are : subject to tides, it is essential that the height of the water at various tidal phases be known. This knowledge is also : essential for prop...

  20. Design rules for piping: Plastic stability of straight parts under level D loadings

    International Nuclear Information System (INIS)

    Touboul, F.; Ben Djidia, M.; Acker, D.

    1989-01-01

    Design rules for piping, elaborated for Fast Breeder Reactors, are based on analysis performed for Pressure Water Reactors. Interpretation of largely diversified straight parts tests, enable us to validate and improve existing rules and to propose a more suitable formula. Design rules for piping appear to be non conservative for austenitic thin tubes in bending or torsion. By introducing a B 2 coefficient, geometrically dependent, the gap between thin and thick tubes may be withheld. Conservatism of rules can be ensured by considering the allowable stress defined by ASME, Section III, Appendix F

  1. Effects of water level on three wetlands soil seed banks on the Tibetan Plateau.

    Directory of Open Access Journals (Sweden)

    Miaojun Ma

    Full Text Available BACKGROUND: Although the effect of water level on germination in soil seed banks has been documented in many ecosystems, the mechanism is not fully understood, and to date no empirical studies on this subject exist. Further, no work has been done on the effect of water level on seed banks of drying and saline-alkaline wetlands in alpine areas on the Tibetan Plateau. METHODOLOGY: We examined the effects of water level (0 cm, 5 cm and 10 cm on seed germination and seedling establishment from soil seed banks at 0-5 cm and 5-10 cm depths in typical, drying, and saline-alkaline wetlands. We also explore the potential role of soil seed bank in restoration of drying and saline-alkaline wetlands. PRINCIPAL FINDINGS: Species richness decreased with increase in water level, but there almost no change in seed density. A huge difference exists in species composition of the seed bank among different water levels in all three wetlands, especially between 0 cm and 5 cm and 0 cm and 10 cm. Similarity of species composition between seed bank and plant community was higher in 0 cm water level in drying wetland than in the other two wetlands. The similarity was much higher in 0 cm water level than in 5 cm and 10 cm water levels in all three wetlands. Species composition of the alpine wetland plant community changed significantly after drying and salinization, however, species composition of the seed bank was unchanged regardless of the environment change. CONCLUSIONS/SIGNIFICANCE: Water level greatly affects seed bank recruitment and plant community establishment. Further, different water levels in restored habitats are likely to determine its species composition of the plant community. The seed bank is important in restoration of degraded wetlands. Successful restoration of drying and salinization wetlands could depend on the seed bank.

  2. Tidal marsh stability in the face of human impacts and sea level rise

    Science.gov (United States)

    Kirwan, M. L.

    2014-12-01

    Coastal populations and marshes have been intertwined for centuries, where humans both influence and depend on the enormous ecosystem services that marshes provide. Although marshes have long been considered vulnerable to climate change, recent work identifies fascinating feedbacks between plant growth and geomorphology that enable them to actively resist sea level rise. Here, we will review existing literature and provide new data to examine how humans alter these feedbacks. Measurements of accretion and elevation change suggest that most marshes will survive present day sea level rise rates by building vertically. Numerical models predict that these marshes will survive moderate accelerations in the rate of sea level in places where dams do not limit sediment delivery to the coast. However, these results also suggest that marsh survival under faster accelerations in sea level will depend on their ability to migrate inland. Marsh transgression into uplands is influenced not only by topography, but also by human land use and decisions to harden shorelines. Preliminary numerical model experiments will be used to explore how basic biophysical and anthropogenic drivers determine whether sea level change will lead to marsh loss (erosion+drowning > transgression), marsh expansion (transgression > erosion), or dynamic equilibrium (transgression = erosion).

  3. Sleep-wake stability in narcolepsy patients with normal, low and unmeasurable hypocretin levels

    DEFF Research Database (Denmark)

    Hansen, Mathias Hvidtfelt; Kornum, Birgitte Rahbek; Jennum, Poul

    2017-01-01

    OBJECTIVE: To compare diurnal and nocturnal electrophysiological data from narcolepsy patients with undetectable (110 pg/mL) cerebrospinal fluid (CSF) hypocretin-1 levels. PATIENTS/METHODS: A total of 109 narcolepsy patients and 37 controls were studied......; all had available CSF hypocretin-1 measurements. The sleep laboratory studies were conducted between 2008 and 2014. The study retrospectively examined measurements of sleep stage transitions in diurnal and nocturnal continuous polysomnography. The percentage distribution of time awake and rapid eye...... movement (REM) sleep, and the occurrence of sleep onset REM (SOREM) in the nocturnal polysomnography were also measured. RESULTS: Participants with undetectable hypocretin-1 levels had significantly higher frequencies of transitions than controls and those with normal hypocretin-1 levels. Participants...

  4. Evaluation of stability of oxytetracycline-HCl to sterilization levels of gamma radiation.

    Science.gov (United States)

    Tawfik, Z S

    1985-01-01

    The effect of gamma irradiation at different dose levels (from 5 to 50 KGy) on the solid state of the antibiotic oxytetracycline-HCl was examined. The results obtained showed no effect on the biological activity of the compound, as investigated by the bioassay technique. The physicochemical properties of the antibiotic were not altered by irradiation dose levels up to 40 KGy. The UV-visible spectra of all irradiated samples showed no changes. The I.R. spectra of oxytetracycline, exposed to dose levels higher than 40 KGy, showed, however, definite destruction in the chemical structure of the antibiotic. HPLC separation of samples, irradiated at 45 KGy, showed the presence of new degradation products. Accordingly, sterilization of oxytetracycline by use of gamma irradiation could be considered safe and applicable, since sterilization doses are usually considered to be less than 30 KGy.

  5. Feasibility of Marine Microalgae Immobilization in Alginate Bead for Marine Water Treatment: Bead Stability, Cell Growth, and Ammonia Removal

    Directory of Open Access Journals (Sweden)

    Chen-Lin Soo

    2017-01-01

    Full Text Available Sodium alginate is the most commonly used polymer matrix in microalgae immobilization for water treatment. However, the susceptibility of alginate matrixes to cation chelating agents and antigelling cation limits the use of alginates in estuarine and marine systems. Hence, the present study aims to investigate the stability of alginate bead in marine water and the feasibility of microalgae to grow when immobilized in alginate bead for marine water treatment. Different concentrations of alginate and hardening cation calcium were used to formulate beads. The beads were incubated in Guillard’s f/2 medium and shaken vigorously by using orbital shaker for 15 days. The results indicated that bead stability was enhanced by increasing alginate and CaCl2 concentrations. Subsequently, the marine microalga, Nannochloropsis sp., was immobilized in calcium alginate bead. The growth and ammoniacal-nitrogen (NH4+-N uptake by immobilized cell were compared with free cell culture in f/2 medium. Specific growth rate of immobilized cell (0.063 hr−1 was significantly higher than free cell (0.027 hr−1. There was no significant difference on specific uptake rate of free cell and immobilized cell; but immobilized cell removed significantly more NH4+-N (82.2% than free cell (47.3% culture at the end of the experiment. The present study demonstrated the potential use of alginate immobilization technique in marine microalgae culture and water treatment simultaneously.

  6. Highly efficient separation of surfactant stabilized water-in-oil emulsion based on surface energy gradient and flame retardancy.

    Science.gov (United States)

    Long, Mengying; Peng, Shan; Deng, Wanshun; Miao, Xinrui; Wen, Ni; Zhou, Qiannan; Deng, Wenli

    2018-06-15

    Surface energy gradient would generate an imbalance force to drive tiny water droplets in dry air from the hydrophilic bumps to superhydrophobic domains, which has found on the Stenocara beetle's back. Inspired by this phenomenon, we introduced a pristine superhydrophilic filter paper on the lower surface energy superhydrophobic filter paper. ZnSn(OH) 6 particles and polydimethylsiloxane were mixed to prepare the superhydrophobic coating, and the coating was spray-coated on the poly(dialkyldimethylammonium chloride) covered filter paper to separate the span 80 stabilized water-in-isooctane emulsion. A pristine filter paper was added on the superhydrophobic filter paper to fabricate another membrane for separation. The results revealed that with a pristine filter paper, the membrane performed higher efficiency and more recyclability, and it could separate the emulsions with higher surfactant concentrations. The stabilized water droplets passed the superamphiphilic surface, and hindered by the superhydrophobic surface, generating a surface energy gradient for better separation. In addition, the superhydrophobic membrane could be protected from fire to some degree due to the introduced ZnSn(OH) 6 particles with excellent flame retardancy. This easy and efficient approach via simply bringing in pristine superhydrophilic membrane has great potential applications for water-in-oil emulsion separation or oil purification. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model

    International Nuclear Information System (INIS)

    Tucci, P.

    2001-01-01

    This Analysis/Model Report (AMR) documents an updated analysis of water-level data performed to provide the saturated-zone, site-scale flow and transport model (CRWMS M and O 2000) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for model calibration. The previous analysis was presented in ANL-NBS-HS-000034, Rev 00 ICN 01, Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model (USGS 2001). This analysis is designed to use updated water-level data as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain. The objectives of this revision are to develop computer files containing (1) water-level data within the model area (DTN: GS010908312332.002), (2) a table of known vertical head differences (DTN: GS0109083 12332.003), and (3) a potentiometric-surface map (DTN: GS010608312332.001) using an alternate concept from that presented in ANL-NBS-HS-000034, Rev 00 ICN 01 for the area north of Yucca Mountain. The updated water-level data include data obtained from the Nye County Early Warning Drilling Program (EWDP) and data from borehole USW WT-24. In addition to being utilized by the SZ site-scale flow and transport model, the water-level data and potentiometric-surface map contained within this report will be available to other government agencies and water users for ground-water management purposes. The potentiometric surface defines an upper boundary of the site-scale flow model, as well as provides information useful to estimation of the magnitude and direction of lateral ground-water flow within the flow system. Therefore, the analysis documented in this revision is important to SZ flow and transport calculations in support of total system performance assessment

  8. Predicted impacts of future water level decline on monitoring wells using a ground-water model of the Hanford Site

    International Nuclear Information System (INIS)

    Wurstner, S.K.; Freshley, M.D.

    1994-12-01

    A ground-water flow model was used to predict water level decline in selected wells in the operating areas (100, 200, 300, and 400 Areas) and the 600 Area. To predict future water levels, the unconfined aquifer system was stimulated with the two-dimensional version of a ground-water model of the Hanford Site, which is based on the Coupled Fluid, Energy, and Solute Transport (CFEST) Code in conjunction with the Geographic Information Systems (GIS) software package. The model was developed using the assumption that artificial recharge to the unconfined aquifer system from Site operations was much greater than any natural recharge from precipitation or from the basalt aquifers below. However, artificial recharge is presently decreasing and projected to decrease even more in the future. Wells currently used for monitoring at the Hanford Site are beginning to go dry or are difficult to sample, and as the water table declines over the next 5 to 10 years, a larger number of wells is expected to be impacted. The water levels predicted by the ground-water model were compared with monitoring well completion intervals to determine which wells will become dry in the future. Predictions of wells that will go dry within the next 5 years have less uncertainty than predictions for wells that will become dry within 5 to 10 years. Each prediction is an estimate based on assumed future Hanford Site operating conditions and model assumptions

  9. Acceptability and storage stability of pork products with increased levels of polyunsaturated fatty acids

    NARCIS (Netherlands)

    Houben, J.H.; Krol, B.

    1980-01-01

    Several batches of back bacon, belly bacon, Dutch-style cervelat sausage, pork loin roll, shoulder with fat, Bologna, Guelders ring sausage, Saxon liver sausage and luncheon meat were produced with increasing PUFA-levels using raw materials containing up to 30% linoleic acid in their fats. Only

  10. Long-term stability and circadian variation in circulating levels of surfactant protein D

    DEFF Research Database (Denmark)

    Hoegh, Silje Vermedal; Sorensen, Grith Lykke; Tornoe, Ida

    2010-01-01

    Surfactant protein D (SP-D) is an oligomeric calcium-dependent lectin with important roles in innate host defence against infectious microorganisms. Several studies have shown that patients with inflammatory lung disease have elevated levels of circulating SP-D, and serum SP-D has been suggested...

  11. Long-term stability of the leveling of the curve of Spee.

    NARCIS (Netherlands)

    Praeter, J. de; Dermaut, L.; Martens, G.D.M.; Kuijpers-Jagtman, A.M.

    2002-01-01

    The aim of the study was to investigate whether the orthodontic leveling of the curve of Spee is a treatment procedure with a stable result on a long-term basis. Measurements were made on the plaster casts of 149 orthodontically treated patients (57 males and 92 females). The mean age before

  12. Stability of trapped electrons in thermally modified alcohol-alcohol and alcohol-water glasses

    International Nuclear Information System (INIS)

    Chlebosz, G.; Kalecinski, J.

    1996-01-01

    Absorption spectra of e t - , DTA and dielectric losses measurements of frozen irradiated matrices of different composition of alcohol-water and alcohol-alcohol have been studied as a function of temperature. In ethylene glycol-water and glycerol-water systems irregularity of e t - decay might be caused by inhomogeneity of the glasses. (author)

  13. Analysis of Long-Term Water Level Variation in Dongting Lake, China

    Directory of Open Access Journals (Sweden)

    Qiaoqian Han

    2016-07-01

    Full Text Available The water level of Dongting Lake has changed because of the combined impact of climatic change and anthropogenic activities. A study of the long-term statistical properties of water level variations at Chenglingji station will help with the management of water resources in Dongting Lake. In this case, 54 years of water level data for Dongting Lake were analyzed with the non-parametric Mann–Kendall trend test, Sen’s slope test, and the Pettitt test. The results showed the following: (1 Trends in annual maximum lake water level (WLM, annual mean lake water level (WL, and annual minimum lake water level (WLm increased from 1961 to 2014; however, the three variables showed different trends from 1981 to 2014; (2 The annual change trends in Dongting Lake between 1961–2014 and 1981–2014 were found to be from approximately 0.90 cm/year to −2.27 cm/year, 1.65 cm/year to −0.79 cm/year, and 4.58 cm/year to 2.56 cm/year for WLM, WL, and WLm, respectively; (3 A greater degree of increase in water level during the dry season (November–April was found from 2003 to 2014 than from 1981 to 2002, but a smaller degree of increase, even to the point of decreasing, was found during the wet season (May–October; (4 The measured discharge data and numerical modeling results showed the operation of Three Gorge Reservoir (TGR pushed to influence partly the recent inter-annual variation of water level in Dongting Lake region, especially in the flood and dry seasons. The analysis indicated that the water level of Dongting Lake has changed in the long term with decreasing of range between WLM and WLm, and may decrease the probability of future drought and flood events. These results can provide useful information for the management of Dongting Lake.

  14. A Screening-Level Hydroeconomic Model of South Florida Water Resources System

    Science.gov (United States)

    Mirchi, A.; Watkins, D. W., Jr.; Flaxman, M.; Wiesmann, D.

    2014-12-01

    South Florida's water resources management is characterized by system-wide tradeoffs associated with maintaining the ecological integrity of natural environments such as the Everglades while meeting the water demands of the agricultural sector and growing urban areas. As these tradeoffs become more pronounced due to pressures from climate change, sea level rise, and population growth, it will be increasingly challenging for policy makers and stakeholders to reach consensus on water resources management objectives and planning horizons. A hydroeconomic optimization model of south Florida's water resources system is developed to incorporate the value of water for preserving ecosystem services alongside water supplies to the Everglades Agricultural Area and urban areas. Results of this screening-level network flow model facilitate quantitative analysis and provide insights for long-term adaptive management strategies for the region's water resources.

  15. Temporal stability and variability of soil-water content in a gravel-mulched field in northwestern China

    Science.gov (United States)

    Zhao, Wenju; Cui, Zhen; Zhang, Jiyi; Jin, Jian

    2017-09-01

    Characterizing the spatiotemporal variability of soil-water content (SWC) is of paramount importance in many scientific fields and operational applications. We present a case study of the temporal stability and variability of SWC in a gravel-mulched field, a form of mulching that has been widely used by farmers on the loessial area of China for over 300 years, using Spearman correlation coefficients, frequency distributions and an index of temporal stability. SWC was measured weekly from May to August 2013 in the 0-10, 10-20, 20-30 and 30-50 cm layers. SWC was more variable in the surface soil, due to several environmental factors, and the variability gradually decreased with depth. A large sample size was needed for estimating the mean SWC of the field under dry conditions. High Spearman correlation coefficients between the SWCs measured on different sampling campaigns indicated a high temporal stability. The stability of the SWC spatial patterns over time and along the soil profile allowed us to identify a location representative of the field-mean SWC, with high coefficients of determination ranging between 0.8564 and 0.9325. The large-scale monitoring of SWC from few observations is thus feasible, which will aid the management of soil moisture in gravel-mulched fields in arid regions.

  16. Ceramic membrane fouling during ultrafiltration of oil/water emulsions: roles played by stabilization surfactants of oil droplets.

    Science.gov (United States)

    Lu, Dongwei; Zhang, Tao; Ma, Jun

    2015-04-07

    Oil/water (O/W) emulsion stabilized by surfactants is the part of oily wastewater that is most difficult to handle. Ceramic membrane ultrafiltration presently is an ideal process to treat O/W emulsions. However, little is known about the fouling mechanism of the ceramic membrane during O/W emulsion treatment. This paper investigated how stabilization surfactants of O/W emulsions influence the irreversible fouling of ceramic membranes during ultrafiltration. An unexpected phenomenon observed was that irreversible fouling was much less when the charge of the stabilization surfactant of O/W emulsions is opposite to the membrane. The less ceramic membrane fouling in this case was proposed to be due to a synergetic steric effect and demulsification effect which prevented the penetration of oil droplets into membrane pores and led to less pore blockage. This proposed mechanism was supported by cross section images of fouled and virgin ceramic membranes taken with scanning electron microscopy, regression results of classical fouling models, and analysis of organic components rejected by the membrane. Furthermore, this mechanism was also verified by the existence of a steric effect and demulsification effect. Our finding suggests that ceramic membrane oppositely charged to the stabilization surfactant should be applied in ultrafiltration of O/W emulsions to alleviate irreversible membrane fouling. It could be a useful rule for ceramic membrane ultrafiltration of oily wastewater.

  17. Ceramic membrane fouling during ultrafiltration of oil/water emulsions: Roles played by stabilization surfactants of oil droplets

    KAUST Repository

    Lu, Dongwei

    2015-04-07

    Oil/water (O/W) emulsion stabilized by surfactants is the part of oily wastewater that is most difficult to handle. Ceramic membrane ultrafiltration presently is an ideal process to treat O/W emulsions. However, little is known about the fouling mechanism of the ceramic membrane during O/W emulsion treatment. This paper investigated how stabilization surfactants of O/W emulsions influence the irreversible fouling of ceramic membranes during ultrafiltration. An unexpected phenomenon observed was that irreversible fouling was much less when the charge of the stabilization surfactant of O/W emulsions is opposite to the membrane. The less ceramic membrane fouling in this case was proposed to be due to a synergetic steric effect and demulsification effect which prevented the penetration of oil droplets into membrane pores and led to less pore blockage. This proposed mechanism was supported by cross section images of fouled and virgin ceramic membranes taken with scanning electron microscopy, regression results of classical fouling models, and analysis of organic components rejected by the membrane. Furthermore, this mechanism was also verified by the existence of a steric effect and demulsification effect. Our finding suggests that ceramic membrane oppositely charged to the stabilization surfactant should be applied in ultrafiltration of O/W emulsions to alleviate irreversible membrane fouling. It could be a useful rule for ceramic membrane ultrafiltration of oily wastewater. © 2015 American Chemical Society.

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

    International Nuclear Information System (INIS)

    O'Brien, G.M.

    1993-01-01

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

  19. Potential of ENVISAT Radar Altimetry for Water Level Monitoring in the Pantanal Wetland

    Directory of Open Access Journals (Sweden)

    Denise Dettmering

    2016-07-01

    Full Text Available Wetlands are important ecosystems playing an essential role for continental water regulation and the hydrologic cycle. Moreover, they are sensitive to climate changes as well as anthropogenic influences, such as land-use or dams. However, the monitoring of these regions is challenging as they are normally located in remote areas without in situ measurement stations. Radar altimetry provides important measurements for monitoring and analyzing water level variations in wetlands and flooded areas. Using the example of the Pantanal region in South America, this study demonstrates the capability and limitations of ENVISAT radar altimeter for monitoring water levels in inundation areas. By applying an innovative processing method consisting of a rigorous data screening by means of radar echo classification as well as an optimized waveform retracking, water level time series with respect to a global reference and with a temporal resolution of about one month are derived. A comparison between altimetry-derived height variations and six in situ time series reveals accuracies of 30 to 50 cm RMS. The derived water level time series document seasonal height variations of up to 1.5 m amplitude with maximum water levels between January and June. Large scale geographical pattern of water heights are visible within the wetland. However, some regions of the Pantanal show water level variations less than a few decimeter, which is below the accuracies of the method. These areas cannot be reliably monitored by ENVISAT.

  20. A linear bi-level multi-objective program for optimal allocation of water resources.

    Directory of Open Access Journals (Sweden)

    Ijaz Ahmad

    Full Text Available This paper presents a simple bi-level multi-objective linear program (BLMOLP with a hierarchical structure consisting of reservoir managers and several water use sectors under a multi-objective framework for the optimal allocation of limited water resources. Being the upper level decision makers (i.e., leader in the hierarchy, the reservoir managers control the water allocation system and tend to create a balance among the competing water users thereby maximizing the total benefits to the society. On the other hand, the competing water use sectors, being the lower level decision makers (i.e., followers in the hierarchy, aim only to maximize individual sectoral benefits. This multi-objective bi-level optimization problem can be solved using the simultaneous compromise constraint (SICCON technique which creates a compromise between upper and lower level decision makers (DMs, and transforms the multi-objective function into a single decision-making problem. The bi-level model developed in this study has been applied to the Swat River basin in Pakistan for the optimal allocation of water resources among competing water demand sectors and different scenarios have been developed. The application of the model in this study shows that the SICCON is a simple, applicable and feasible approach to solve the BLMOLP problem. Finally, the comparisons of the model results show that the optimization model is practical and efficient when it is applied to different conditions with priorities assigned to various water users.