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Sample records for constant water content

  1. Dynamic and spectroscopic studies of nano-micelles comprising dye in water/ dioctyl sodium sulfosuccinate /decane droplet microemulsion at constant water content

    NASA Astrophysics Data System (ADS)

    Rahdar, Abbas; Almasi-Kashi, Mohammad

    2017-01-01

    In the present work, the dynamic and spectroscopic properties of water-in-decane dioctyl sodium sulfosuccinate (AOT) microemulsions comprising dye, Rhodamine B (RB), were studied by varying content of decane at the constant water content (W = 20), by using dynamic light scattering (DLS), UV/visible, and fluorescence techniques. The characterization results of DLS of AOT micelles showed that by decreasing concentration of Rhodamine B in the water/AOT/decane microemulsion, the inter-droplet interactions changed from attractive to repulsive as the mass fraction of nano-droplets (MFD) increased. A deviation in the absorption spectra of Rhodamine B from the Beer's law at the high Rhodamine B concentration (0.001) was observed in the AOT reversed micelles. The Quenching in the emission intensity of AOT droplets comprising Rhodamine B and red shift in λmax of fluorescence of dye was observed as a function of concentration of RB in AOT RMs. The Stokes shift of AOT droplets containing the high concentration of RB, increased with mass fraction of nano-droplet (MFD), whereas at the low Rhodamine B concentration, its variation remained constant up to MFD = 0.07, and then increased.

  2. The effects of water content and water resistivity on the dispersion of resistivity and dielectric constant in quartz sand in the frequency range 10^2 to 10^8 Hz

    USGS Publications Warehouse

    Eberle, W.R.

    1983-01-01

    Using modifications of previously developed methods, measurements were made of the resistivity and the dielectric constant of two similar quartz sands of different porosity over the frequency range 102-108 Hertz for various water contents and water resistivities. Dispersion is pronounced in all the resistivity data above 106 Hz. As water content decreases, resistivity dispersion becomes noticeable at lower frequencies. The resistivity data at all frequencies, however, fit an empirical prediction formula relating observed resistivity to water saturation and resistivity of the saturated sample. The data suggest that the dispersion of resistivity of some earth materials with frequency may be predicted on the basis of curve matching of the data obtained in this investigation with the resistivity of the material at a frequency of 100 Hz or lower. The dispersion of dielectric constant with frequency is pronounced at all frequencies, being more pronounced with increasing water content. The shape of the dispersion curve is dependent on the resistivity of the water in the sample.

  3. Water dimer equilibrium constant of saturated vapor

    NASA Astrophysics Data System (ADS)

    Malomuzh, N. P.; Mahlaichuk, V. N.; Khrapatyi, S. V.

    2014-08-01

    The value and temperature dependence of the dimerization constant for saturated water vapor are determined. A general expression that links the second virial coefficient and the dimerization constant is obtained. It is shown that the attraction between water monomers and dimers is fundamental, especially at T > 350 K. The range of application for the obtained results is determined.

  4. Dielectric constant of water in the interface

    NASA Astrophysics Data System (ADS)

    Dinpajooh, Mohammadhasan; Matyushov, Dmitry V.

    2016-07-01

    We define the dielectric constant (susceptibility) that should enter the Maxwell boundary value problem when applied to microscopic dielectric interfaces polarized by external fields. The dielectric constant (susceptibility) of the interface is defined by exact linear-response equations involving correlations of statistically fluctuating interface polarization and the Coulomb interaction energy of external charges with the dielectric. The theory is applied to the interface between water and spherical solutes of altering size studied by molecular dynamics (MD) simulations. The effective dielectric constant of interfacial water is found to be significantly lower than its bulk value, and it also depends on the solute size. For TIP3P water used in MD simulations, the interface dielectric constant changes from 9 to 4 when the solute radius is increased from ˜5 to 18 Å.

  5. Profiling soil water content sensor

    USDA-ARS?s Scientific Manuscript database

    A waveguide-on-access-tube (WOAT) sensor system based on time domain reflectometry (TDR) principles was developed to sense soil water content and bulk electrical conductivity in 20-cm (8 inch) deep layers from the soil surface to depths of 3 m (10 ft) (patent No. 13/404,491 pending). A Cooperative R...

  6. Computing the dielectric constant of liquid water at constant dielectric displacement

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Sprik, Michiel

    2016-04-01

    The static dielectric constant of liquid water is computed using classical force field based molecular dynamics simulation at fixed electric displacement D . The method to constrain the electric displacement is the finite-temperature classical variant of the constant D method developed by Stengel, Spaldin, and Vanderbilt [Nat. Phys. 5, 304 (2009), 10.1038/nphys1185]. There is also a modification of this scheme imposing fixed values of the macroscopic field E . The method is applied to the popular SPC/E model of liquid water. We compare four different estimates of the dielectric constant, two obtained from fluctuations of the polarization at D =0 and E =0 and two from the variation of polarization with finite D and E . It is found that all four estimates agree when properly converged. The computational effort to achieve convergence varies, however, with constant D calculations being substantially more efficient. We attribute this difference to the much shorter relaxation time of longitudinal polarization compared to transverse polarization accelerating constant D calculations.

  7. 21 CFR 1250.42 - Water systems; constant temperature bottles.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... and protected as to minimize the hazard of contamination of the water supply. (c) On all new or... used on dining cars and other conveyances will be permitted only if they are so operated and maintained at all times as to prevent contamination of the water. (e) Constant temperature bottles and other...

  8. 21 CFR 1250.42 - Water systems; constant temperature bottles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and protected as to minimize the hazard of contamination of the water supply. (c) On all new or... used on dining cars and other conveyances will be permitted only if they are so operated and maintained at all times as to prevent contamination of the water. (e) Constant temperature bottles and other...

  9. 21 CFR 1250.42 - Water systems; constant temperature bottles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... and protected as to minimize the hazard of contamination of the water supply. (c) On all new or... used on dining cars and other conveyances will be permitted only if they are so operated and maintained at all times as to prevent contamination of the water. (e) Constant temperature bottles and other...

  10. 21 CFR 1250.42 - Water systems; constant temperature bottles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... and protected as to minimize the hazard of contamination of the water supply. (c) On all new or... used on dining cars and other conveyances will be permitted only if they are so operated and maintained at all times as to prevent contamination of the water. (e) Constant temperature bottles and other...

  11. 21 CFR 1250.42 - Water systems; constant temperature bottles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... and protected as to minimize the hazard of contamination of the water supply. (c) On all new or... used on dining cars and other conveyances will be permitted only if they are so operated and maintained at all times as to prevent contamination of the water. (e) Constant temperature bottles and other...

  12. Sugar and water contents of honey with dielectrc property sensing

    USDA-ARS?s Scientific Manuscript database

    The dielectric properties of pure yellow locust, jujube and rape flower honey and their water-adulterated products with water content from 18% to 42.6% were measured with open-ended coaxial-line probe technology and a network analyzer from 10 to 4500 MHz at 25oC. Dielectric constants of pure honeys ...

  13. Remote Sensing of Salinity: The Dielectric Constant of Sea Water

    NASA Technical Reports Server (NTRS)

    LeVine, David M.; Lang, R.; Utku, C.; Tarkocin, Y.

    2011-01-01

    Global monitoring of sea surface salinity from space requires an accurate model for the dielectric constant of sea water as a function of salinity and temperature to characterize the emissivity of the surface. Measurements are being made at 1.413 GHz, the center frequency of the Aquarius radiometers, using a resonant cavity and the perturbation method. The cavity is operated in a transmission mode and immersed in a liquid bath to control temperature. Multiple measurements are made at each temperature and salinity. Error budgets indicate a relative accuracy for both real and imaginary parts of the dielectric constant of about 1%.

  14. he Ion-Product Constant of Water to 350°

    USGS Publications Warehouse

    Fisher, J.R.; Barnes, H.L.

    1972-01-01

    The ion-activity product of water, KW0, has been determined to 350?? along the liquid-vapor curve from conductance measurements made between 100 and 350?? on aqueous solutions in the system acetic acid-ammonium acetate-ammonia. Derivation of KW0 requires data on the limiting equivalent conductivities of acetic acid, ammonia, and ammonium acetate, the ionization constants of acetic acid and ammonia, and of the conductivities of pairs of these solutes at a series of concentrations. The limiting equivalent conductivities were indirectly obtained from literature data on the limiting equivalent conductivities of HCl, NaCl, NaOH, NH4Cl, and NaOAc. The ionization constants of acetic acid were obtained from our conductance measurements combined with literature data; constants for ammonia were obtained from the literature. From our conductivities, values of KW0 were obtained between 100 and 350??; these were combined with well established literature values and the combined set analytically smoothed to provide a consistent set of molal constants from 25 to 350??; respective pK's at 150, 250, and 350?? are: for H2O, 11.64, 11.05, and 11.42; for HOAc, 5.22, 5.95, and 7.68; and for NH4OH, 5.11, 5.91, and 7.30.

  15. Estimating canopy water content from spectroscopy

    USDA-ARS?s Scientific Manuscript database

    Foliar water content is a dynamic quantity depending on water losses from transpiration and water uptake from the soil. Absorption of shortwave radiation by water is determined by various frequency overtones of fundamental bending and stretching molecular transitions. Leaf water potential and rela...

  16. Ice Particle Impact on Cloud Water Content Instrumentation

    NASA Technical Reports Server (NTRS)

    Emery, Edward F.; Miller, Dean R.; Plaskon, Stephen R.; Strapp, Walter; Lillie, Lyle

    2004-01-01

    Determining the total amount of water contained in an icing cloud necessitates the measurement of both the liquid droplets and ice particles. One commonly accepted method for measuring cloud water content utilizes a hot wire sensing element, which is maintained at a constant temperature. In this approach, the cloud water content is equated with the power required to keep the sense element at a constant temperature. This method inherently assumes that impinging cloud particles remain on the sensing element surface long enough to be evaporated. In the case of ice particles, this assumption requires that the particles do not bounce off the surface after impact. Recent tests aimed at characterizing ice particle impact on a thermally heated wing section, have raised questions about the validity of this assumption. Ice particles were observed to bounce off the heated wing section a very high percentage of the time. This result could have implications for Total Water Content sensors which are designed to capture ice particles, and thus do not account for bouncing or breakup of ice particles. Based on these results, a test was conducted to investigate ice particle impact on the sensing elements of the following hot-wire cloud water content probes: (1) Nevzorov Total Water Content (TWC)/Liquid Water Content (LWC) probe, (2) Science Engineering Associates TWC probe, and (3) Particle Measuring Systems King probe. Close-up video imaging was used to study ice particle impact on the sensing element of each probe. The measured water content from each probe was also determined for each cloud condition. This paper will present results from this investigation and attempt to evaluate the significance of ice particle impact on hot-wire cloud water content measurements.

  17. Constant-pressure measurement of steam-water relative permeability

    SciTech Connect

    O'Connor, Peter A.

    2001-06-01

    A series of steady-state experiments have established relative permeability curves for two-phase flow of water in a porous medium. These experiments have minimized uncertainty in pressure, heat loss, and saturation. By attempting to maintain a constant pressure gradient, the experiments have provided a baseline from which to determine the effect of temperature on relative permeability. The use of a flexible heater with an automatic control system made it possible to assume negligible phase change for the mobile fluid. X-ray computer tomography (CT) aided by measuring in-situ steam saturation more directly. Mobile steam mass fraction was established by separate steam and water inlets or by correlating with previous results. The measured steam-water relative permeability curves assume a shape similar to those obtained by Corey (1954) for the simultaneous flow of nitrogen and water. Close agreement between the curves by Satik (1998), Mahiya (1999), and this study establishes the reliability of the experimental method and instrumentation adopted in these experiments, though some differences may bear further investigation. In particular, the steam phase relative permeability appears to vary much more linearly with saturation than does the water phase relative permeability.

  18. Use of Water Content Reflectometers in Bioinfiltration/Bioretention to Measure Water Movement and Estimate Evapotranspiration

    EPA Science Inventory

    Most bioinfiltration/bioretention models assume runoff is evenly distributed across the surface area and after the engineered fill media is no longer saturated, the volumetric water content (VWC) is constant throughout the media profile and at field capacity. Four to nine water ...

  19. Use of Water Content Reflectometers in Bioinfiltration/Bioretention to Measure Water Movement and Estimate Evapotranspiration

    EPA Science Inventory

    Most bioinfiltration/bioretention models assume runoff is evenly distributed across the surface area and after the engineered fill media is no longer saturated, the volumetric water content (VWC) is constant throughout the media profile and at field capacity. Four to nine water ...

  20. Water content in convective storm clouds.

    PubMed

    Kyle, T G; Sand, W R

    1973-06-22

    The condensed water content of convective storms was measured by the use of a penetrating aircraft. Regions 1 to 2 kilometers in extent and having condensed water contents of about 20 grams per cubic meter were found to be definite features of the cloud interior.

  1. Microwave measurements of the water content of bentonite

    SciTech Connect

    Latorre, V.R.; Glenn, H.D.

    1991-01-01

    The theory of operation of microwave coaxial resonators is described. Sample preparation and the application of resonator techniques to the measurement of the permittivity (dielectric constant) of bentonite is discussed. The results indicate a fairly linear change in resonant frequency for saturation levels at 10, 30, 50, 70, and 90%. The results clearly demonstrate that this microwave technique is a viable method for measuring water content of soils. A discussion of additional applications of microwave methods for determining water content in materials is presented. 3 refs., 5 figs.

  2. Characterization of Cloud Water-Content Distribution

    NASA Technical Reports Server (NTRS)

    Lee, Seungwon

    2010-01-01

    The development of realistic cloud parameterizations for climate models requires accurate characterizations of subgrid distributions of thermodynamic variables. To this end, a software tool was developed to characterize cloud water-content distributions in climate-model sub-grid scales. This software characterizes distributions of cloud water content with respect to cloud phase, cloud type, precipitation occurrence, and geo-location using CloudSat radar measurements. It uses a statistical method called maximum likelihood estimation to estimate the probability density function of the cloud water content.

  3. The mechanism of sulforaphene degradation to different water contents.

    PubMed

    Tian, Guifang; Li, Yuan; Cheng, Li; Yuan, Qipeng; Tang, Pingwah; Kuang, Pengqun; Hu, Jing

    2016-03-01

    Sulforaphene extracted from radish seeds was strongly associated with cancer prevention. However, sulforaphene was unstable in aqueous medium and at high temperature. This instability impairs many useful applications of sulforaphene. In this paper, the stability of sulforaphene (purity above 95%) during storage at -20°C, 4°C and 26°C was studied. The degradation product was purified by preparative HPLC and identified by ESI/MS, NMR ((1)H and (13)C NMR) and FTIR spectroscopy. The degradation pathway of sulforaphene was presented. Furthermore, we found that the degradation rate of sulforaphene was closely related to the water content of sulforaphene sample. The higher the water content was, the faster the sulforaphene sample degraded. A mathematical model was developed to predict the degradation constant at various water contents. It provided a guideline for industry to improve the stability of sulforaphene during preparation, application and storage. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. [Ethanol content of Kefir water].

    PubMed

    Rabl, W; Liniger, B; Sutter, K; Sigrist, T

    1994-03-01

    The question of the influence of kefir on blood-alcohol-level has been asked in a legal proceeding. The questioned recipe consisted of 21 water, 6 soup-spoons of kefir granules (about 120 g), 150 g sugar, 2 figs and one lemon. The consumption took place after two days of fermentation. Experimentally we found, that one liter of this kefir product may contain up to 38 g/l ethanol after 7 to 10 days. On the second day we measured up to 16 g/l ethanol. Our results may be import for expert appraisements concerning unability of driving.

  5. Dielectric constant of ices and water: a lesson about water interactions.

    PubMed

    Aragones, J L; MacDowell, L G; Vega, C

    2011-06-16

    In this paper, the dielectric constant has been evaluated for ices Ih, III, V, VI, and VII for several water models using two different methodologies. Using Monte Carlo simulations, with special moves to sample proton-disordered configurations, the dielectric constant has been rigorously evaluated. We also used an approximate route in which proton-disordered configurations satisfying the Bernal-Fowler rules were generated following the algorithm proposed by Buch et al. (Buch, V.; Sandler, P.; Sadlej, J. J. Phys. Chem. B 1998, 102, 8641), and the dielectric constant was estimated assuming that all configurations have the same statistical weight (as Pauling did when estimating the residual entropy of ice). The predictions of the Pauling model for the dielectric constant differ in general from those obtained rigorously by computer simulations because proton-disordered configurations satisfying the Bernal-Fowler rules can differ in their energies by as much as 0.10-0.30 NkT (at 243 K). These differences in energy significantly affect properties that vary from one configuration to another such as polarization, leading to different values of the dielectric constant. The Pauling predictions differ from the simulation results, especially for SPC/E and TIP5P, but yield reasonable results for TIP4P-like models. We suggest that for three charge models the polarization factor (G) in condensed phases depends on the ratio of the dipole to the quadrupole moment. The SPC/E, TIP5P, TIP4P, TIP4P/2005, TIP4P/ice models of water are unable to describe simultaneously both the experimental dielectric constants of water and ice Ih. Nonpolarizable models cannot describe the dielectric constants of the different condensed phases of water because their dipole moments (about 2.3 D) are much smaller that those estimated from first principles (of the order of 3 D). However, the predictions of TIP4P models provide an overall qualititatively correct description of the dielectric constant of the

  6. Infrared Spectroscopy and Optical Constants of Porous Amorphous Solid Water

    SciTech Connect

    Cholette, Francois; Zubkov, Tykhon; Smith, R. Scott; Dohnalek, Zdenek; Kay, Bruce D.; Ayotte, Patrick

    2009-04-02

    Reflection-absorption infrared spectra (RAIRS) of amorphous solid water (ASW) films grown at 20K on a Pt(111) substrate at various incidence angle (θBeam = 0-85o) using a molecular beam are reported. They display complex features arising from the interplay between refraction, absorption within the sample, and interference effects between the multiple reflections at the film-substrate and film-vacuum interfaces. Using a simple classical optics model based on Fresnel equations, we obtain optical constants [i.e., n(ω) and k(ω)] for porous ASW in the 1000-4000cm-1 (10-2.5 μm) range. The behaviour of the optical properties of ASW in the intramolecular OH stretching region with increasing θBeam is shown to be strongly correlated with its decreasing density and increasing surface area. A direct comparison between the RAIRS and calculated vibrational spectra shows a large difference (~200cm-1) in the position of the coupled H-bonded intramolecular OH stretching vibrations spectral feature. Moreover, this band shifts in opposite directions with increasing θBeam in RAIRS and vibrational spectra demonstrating RAIRS spectra cannot be interpreted straightforwardly as vibrational spectra due to severe optical distortions from refraction and interference effects.

  7. Fluoride content of tank water in Australia.

    PubMed

    Cochrane, N J; Hopcraft, M S; Tong, A C; Thean, H l; Thum, Y S; Tong, D E; Wen, J; Zhao, S C; Stanton, D P; Yuan, Y; Shen, P; Reynolds, E C

    2014-06-01

    The aims of this study were to: (1) analyse the fluoride content of tank water; (2) determine whether the method of water collection or storage influenced fluoride content; and (3) survey participant attitudes towards water fluoridation. Plastic tubes and a questionnaire were distributed through dentists to households with water tanks in Victoria. A midstream tank water sample was collected and fluoride analysed in triplicate using ion chromatography All samples (n = 123) contained negligible amounts of fluoride, with a mean fluoride concentration of <0.01 ppm (range: <0.01-0.18 ppm). No statistically significant association was found between fluoride content and variables investigated such as tank material, tank age, roof material and gutter material. Most people did not know whether their tank water contained fluoride and 40.8% preferred to have access to fluoridated water. The majority thought fluoride was safe and more than half of the respondents supported fluoridation. Fluoride content of tank water was well below the optimal levels for caries prevention. People who rely solely on tank water for drinking may require additional exposure to fluoride for optimal caries prevention. © 2014 Australian Dental Association.

  8. Simultaneous measurement of unfrozen water content and ice content in frozen soil using gamma ray attenuation and TDR

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaohai; Zhou, Jian; Kinzelbach, Wolfgang; Stauffer, Fritz

    2014-12-01

    The freezing temperature of water in soil is not constant but varies over a range determined by soil texture. Consequently, the amounts of unfrozen water and ice change with temperature in frozen soil, which in turn affects hydraulic, thermal, and mechanical properties of frozen soil. In this paper, an Am-241 gamma ray source and time-domain reflectometry (TDR) were combined to measure unfrozen water content and ice content in frozen soil simultaneously. The gamma ray attenuation was used to determine total water content. The TDR was used to determine the dielectric constant of the frozen soil. Based on a four-phase mixing model, the amount of unfrozen water content in the frozen soil could be determined. The ice content was inferred by the difference between total water content and unfrozen water content. The gamma ray attenuation and the TDR were both calibrated by a gravimetric method. Water contents measured by gamma ray attenuation and TDR in an unfrozen silt column under infiltration were compared and showed that the two methods have the same accuracy and response to changes of water content. Unidirectional column freezing experiments were performed to apply the combined method of gamma ray attenuation and TDR for measuring unfrozen water content and ice content. The measurement error of the gamma ray attenuation and TDR was around 0.02 and 0.01 m3/m3, respectively. The overestimation of unfrozen water in frozen soil by TDR alone was quantified and found to depend on the amount of ice content. The higher the ice content, the larger the overestimation. The study confirmed that the combined method could accurately determine unfrozen water content and ice content in frozen soil. The results of soil column freezing experiments indicate that total water content distribution is affected by available pore space and the freezing front advance rate. It was found that there is similarity between the soil water characteristic and the soil freezing characteristic of

  9. Water Relations, Gas Exchange, and Nutrient Response to a Long Term Constant Water Deficit

    NASA Technical Reports Server (NTRS)

    Berry, Wade L.; Goldstein, Guillermo; Dreschel, Thomas W.; Wheeler, Raymond M.; Sager, John C.; Knott, William M.

    1992-01-01

    Wheat plants (Triticum aestivum) were grown for 43 days in a micro-porous tube nutrient delivery system. Roots were unable to penetrate the microporous tube, but grew on the surface and maintained capillary contact with the nutrient solution on the inside of the tube through the 5-microns pores of the porous tube. Water potential in the system was controlled at -0.4, -0.8, and -3.0 kPa by adjusting the applied pressure (hydrostatic head) to the nutrient solution flowing through the microporous tubes. A relatively small decrease in applied water potential from -0.4 to -3.0 kPa resulted in a 34% reduction of shoot growth but only a moderate reduction in the mid-day leaf water potential from - 1.3 to - 1.7 MPa. Carbon dioxide assimilation decreased and water use efficiency increased with the more negative applied water Potentials, while intercellular C02 concentration remained constant. The physiological responses observed in this study in response to small constant differences in applied water potentials were much greater than expected from either the applied water potential or the observed plant water potential. Even though the micro-porous tube may not represent natural conditions and could possibly introduce morphological and physiological artifacts , it enables a high degree of control of water potential that facilitates the investigation of many aspects of water relations not practical with other experimental systems.

  10. Water Relations, Gas Exchange, and Nutrient Response to a Long Term Constant Water Deficit

    NASA Technical Reports Server (NTRS)

    Berry, Wade L.; Goldstein, Guillermo; Dreschel, Thomas W.; Wheeler, Raymond M.; Sager, John C.; Knott, William M.

    1992-01-01

    Wheat plants (Triticum aestivum) were grown for 43 days in a micro-porous tube nutrient delivery system. Roots were unable to penetrate the microporous tube, but grew on the surface and maintained capillary contact with the nutrient solution on the inside of the tube through the 5-microns pores of the porous tube. Water potential in the system was controlled at -0.4, -0.8, and -3.0 kPa by adjusting the applied pressure (hydrostatic head) to the nutrient solution flowing through the microporous tubes. A relatively small decrease in applied water potential from -0.4 to -3.0 kPa resulted in a 34% reduction of shoot growth but only a moderate reduction in the mid-day leaf water potential from - 1.3 to - 1.7 MPa. Carbon dioxide assimilation decreased and water use efficiency increased with the more negative applied water Potentials, while intercellular C02 concentration remained constant. The physiological responses observed in this study in response to small constant differences in applied water potentials were much greater than expected from either the applied water potential or the observed plant water potential. Even though the micro-porous tube may not represent natural conditions and could possibly introduce morphological and physiological artifacts , it enables a high degree of control of water potential that facilitates the investigation of many aspects of water relations not practical with other experimental systems.

  11. Detection of Plant Water Content with Needle-Type In-Situ Water Content Sensor

    NASA Astrophysics Data System (ADS)

    Katayanagi, Hitoshi; Miki, Norihisa

    A needle-type water content sensor with a polyethersulfone (PES) polymer membrane was developed for the low-invasive, direct in-situ measurement of plant water content (PWC) in prior work. In this paper we demonstrate a measurement of plant water stress that represents the demand for water of the plant and greatly affects its sweetness. We inserted the sensor into a stalk of strawberry (Fragaria×ananassa) and soil. The variation in both the plant and the soil water content were successfully detected, which revealed the delay between variation in the plant water stress and soil water content after irrigation. Such delay could only be detected by the proposed sensor that could directly measure the variation of PWC in situ and continuously. The experiments also showed the variation in the signals as a function of detection sites and suggested that the detection sites of plant water stress need to be considered when the sensor is applied to irrigation culture.

  12. Effect of water content on the acid-base equilibrium of cyanidin-3-glucoside.

    PubMed

    Coutinho, Isabel B; Freitas, Adilson; Maçanita, António L; Lima, J C

    2015-04-01

    Laser Flash Photolysis was employed to measure the deprotonation and reprotonation rate constants of cyanidin 3-monoglucoside (kuromanin) in water/methanol mixtures. It was found that the deprotonation rate constant kd decreases with decreasing water content, reflecting the lack of free water molecules around kuromanin, which may accommodate and stabilize the outgoing protons. On the other hand, the reprotonation rate constant, kp, increases with the decrease in water concentration from a value of kp = 2 × 10(10) l mol(-1) s(-1) in water up to kp = 6 × 10(10) l mol(-1) s(-1) at 5.6M water concentration in the mixture. The higher value of kp at lower water concentrations reflects the fact that the proton is not freely escaping the solvation shell of the molecule. The deprotonation rate constant decreases with decreasing water content, reflecting the lack of free water molecules around kuromanin that can accommodate the outgoing protons. Overall, the acidity constant of the flavylium cation decreases with the decrease in water concentration from pKa values of 3.8 in water to approximately 4.8 in water-depleted media, thus shifting the equilibrium towards the red-coloured form, AH(+), at low water contents. The presence, or lack, of water, will affect the colour shade (red to blue) of kuromanin. This is relevant for its role as an intrinsic food component and as a food pigment additive (E163).

  13. Water Content of Lunar Alkali Fedlspar

    NASA Technical Reports Server (NTRS)

    Mills, R. D.; Simon, J. I.; Wang, J.; Alexander, C. M. O'D.; Hauri, E. H.

    2016-01-01

    Detection of indigenous hydrogen in a diversity of lunar materials, including volcanic glass, melt inclusions, apatite, and plagioclase suggests water may have played a role in the chemical differentiation of the Moon. Spectroscopic data from the Moon indicate a positive correlation between water and Th. Modeling of lunar magma ocean crystallization predicts a similar chemical differentiation with the highest levels of water in the K- and Th-rich melt residuum of the magma ocean (i.e. urKREEP). Until now, the only sample-based estimates of water content of KREEP-rich magmas come from measurements of OH, F, and Cl in lunar apatites, which suggest a water concentration of < 1 ppm in urKREEP. Using these data, predict that the bulk water content of the magma ocean would have <10 ppm. In contrast, estimate water contents of 320 ppm for the bulk Moon and 1.4 wt % for urKREEP from plagioclase in ferroan anorthosites. Results and interpretation: NanoSIMS data from granitic clasts from Apollo sample 15405,78 show that alkali feldspar, a common mineral in K-enriched rocks, can have approx. 20 ppm of water, which implies magmatic water contents of approx. 1 wt % in the high-silica magmas. This estimate is 2 to 3 orders of magnitude higher than that estimated from apatite in similar rocks. However, the Cl and F contents of apatite in chemically similar rocks suggest that these melts also had high Cl/F ratios, which leads to spuriously low water estimates from the apatite. We can only estimate the minimum water content of urKREEP (+ bulk Moon) from our alkali feldspar data because of the unknown amount of degassing that led to the formation of the granites. Assuming a reasonable 10 to 100 times enrichment of water from urKREEP into the granites produces an estimate of 100-1000 ppm of water for the urKREEP reservoir. Using the modeling of and the 100-1000 ppm of water in urKREEP suggests a minimum bulk silicate Moon water content between 2 and 20 ppm. However, hydrogen loss was

  14. Microwave remote sensing of soil water content

    NASA Technical Reports Server (NTRS)

    Cihlar, J.; Ulaby, F. T.

    1975-01-01

    Microwave remote sensing of soils to determine water content was considered. A layered water balance model was developed for determining soil water content in the upper zone (top 30 cm), while soil moisture at greater depths and near the surface during the diurnal cycle was studied using experimental measurements. Soil temperature was investigated by means of a simulation model. Based on both models, moisture and temperature profiles of a hypothetical soil were generated and used to compute microwave soil parameters for a clear summer day. The results suggest that, (1) soil moisture in the upper zone can be predicted on a daily basis for 1 cm depth increments, (2) soil temperature presents no problem if surface temperature can be measured with infrared radiometers, and (3) the microwave response of a bare soil is determined primarily by the moisture at and near the surface. An algorithm is proposed for monitoring large areas which combines the water balance and microwave methods.

  15. [Water consumption in Saharan nomads. A remarkably reduced and constant consumption].

    PubMed

    Paque, C

    1976-10-02

    The writer has carried out two studies of the Western Sahara (Missions UNESCO-Institut Scientifique Cherifien 1961 and 1964) bearing upon the consumption of water by the Saharan nomads. In spite of their environment, the consumption appeared to be remarkably low and constant. Very strict dietary practices, the salinity of the water, and special behavioural customs seemed to be the basis of this strict economy of fluid intake. Genetic factors could also, of course, be partly responsible. The dietary practices are characterised essentially: 1) by a regime which in general contains the minimum of protein: milk foods, cereals, and sugars, and 2) by the habitual exclusion of salt in the preparation of meals; the sodium necessary for water/sodium balance deriving solely from the salinity of the water. Water with little or average salt content (total 2-3 g/l) seems to meet the normal needs of the body - there is no need for the salt pill - and, moreover, to quench the thirst more effectively than pure water (Paque, 1964) - presumably by making good the deficit (cf. Stricker, 1970). On the other hand, saltier water (total 4-8g/; Na 1 g/l or more) appears to pose more complex physiological problems for which the prime solution is to apply the Saharan rule, i.e. that no supplementary salt should be added to the diet (Paque, 1963). In desert life there are thus certain rules which must be obeyed. As for the matter of behavioural customs influencing water balance, they consist in the main of habitually limiting the frequency of water intake (often just twice daily, sometime only once daily) together with a careful choice of clothing and the wearing of the veil. Finally, genetic factor could result in a more efficiently controlled loss of water (and of salt?) VIA THE SKIN.

  16. Water Relations, Gas Exchange, and Nutrient Response to a Long Term Constant Water Deficit

    NASA Technical Reports Server (NTRS)

    Berry, Wade L.; Goldstein, Guillermo; Dreschel, Thomas W.; Wheeler, Raymond M.; Sager, John C.; Knott, William M.

    1992-01-01

    Wheat plants (Triticum aestivum) were grown for 43 days in a micro-porous tube nutrient delivery system. Roots were unable to penetrate the microporous tube, but grew on the surface and maintained capillary contact with the nutrient solution on the inside of the tube through the 5-micron pores of the porous tube. Water potential in the system was controlled at -0.4, -0.8, and -3.0 kPa by adjusting the applied pressure (hydrostatic head) to the nutrient solution flowing through the microporous tubes. A relatively small decrease in applied water potential from -0.4 to -3.0 kPa resulted in a 34% reduction of shoot growth but only a moderate reduction in the midday leaf water potential from -1.3 to -1.7 MPa. Carbon dioxide assimilation decreased and water use efficiency increased with the more negative applied water potentials, while intercellular CO2 concentration remained constant. This was associated with a decrease in stomatal conductance to water vapor from 1.90 to 0.98 mol/(sq m sec) and a decrease in total apparent hydraulic conductance from 47 to 12 (micro)mol/(sec MPa). Although the applied water potentials were in the -0.4 to -3.0 kPa range, the actual water potential perceived by the plant roots appeared to be in the range of -0.26 to -0.38 MPa as estimated by the leaf water potential of bagged plants. The amount of K, Ca, Mg, Zn, Cu, and B accumulated with each unit of transpired water increased as the applied water potential became less negative. The increase in accumulation ranged from 1.4-fold for K to 2.2-fold for B. The physiological responses observed in this study in response to small constant differences in applied water potentials were much greater than expected from either the applied water potential or the observed plant water potential. Even though the micro-porous tube may not represent natural conditions and could possibly introduce morphological and physiological artifacts, it enables a high degree of control of water potential that

  17. Water Relations, Gas Exchange, and Nutrient Response to a Long Term Constant Water Deficit

    NASA Technical Reports Server (NTRS)

    Berry, Wade L.; Goldstein, Guillermo; Dreschel, Thomas W.; Wheeler, Raymond M.; Sager, John C.; Knott, William M.

    1992-01-01

    Wheat plants (Triticum aestivum) were grown for 43 days in a micro-porous tube nutrient delivery system. Roots were unable to penetrate the microporous tube, but grew on the surface and maintained capillary contact with the nutrient solution on the inside of the tube through the 5-micron pores of the porous tube. Water potential in the system was controlled at -0.4, -0.8, and -3.0 kPa by adjusting the applied pressure (hydrostatic head) to the nutrient solution flowing through the microporous tubes. A relatively small decrease in applied water potential from -0.4 to -3.0 kPa resulted in a 34% reduction of shoot growth but only a moderate reduction in the midday leaf water potential from -1.3 to -1.7 MPa. Carbon dioxide assimilation decreased and water use efficiency increased with the more negative applied water potentials, while intercellular CO2 concentration remained constant. This was associated with a decrease in stomatal conductance to water vapor from 1.90 to 0.98 mol/(sq m sec) and a decrease in total apparent hydraulic conductance from 47 to 12 (micro)mol/(sec MPa). Although the applied water potentials were in the -0.4 to -3.0 kPa range, the actual water potential perceived by the plant roots appeared to be in the range of -0.26 to -0.38 MPa as estimated by the leaf water potential of bagged plants. The amount of K, Ca, Mg, Zn, Cu, and B accumulated with each unit of transpired water increased as the applied water potential became less negative. The increase in accumulation ranged from 1.4-fold for K to 2.2-fold for B. The physiological responses observed in this study in response to small constant differences in applied water potentials were much greater than expected from either the applied water potential or the observed plant water potential. Even though the micro-porous tube may not represent natural conditions and could possibly introduce morphological and physiological artifacts, it enables a high degree of control of water potential that

  18. [The water content reference material of water saturated octanol].

    PubMed

    Wang, Haifeng; Ma, Kang; Zhang, Wei; Li, Zhanyuan

    2011-03-01

    The national standards of biofuels specify the technique specification and analytical methods. A water content certified reference material based on the water saturated octanol was developed in order to satisfy the needs of the instrument calibration and the methods validation, assure the accuracy and consistency of results in water content measurements of biofuels. Three analytical methods based on different theories were employed to certify the water content of the reference material, including Karl Fischer coulometric titration, Karl Fischer volumetric titration and quantitative nuclear magnetic resonance. The consistency of coulometric and volumetric titration was achieved through the improvement of methods. The accuracy of the certified result was improved by the introduction of the new method of quantitative nuclear magnetic resonance. Finally, the certified value of reference material is 4.76% with an expanded uncertainty of 0.09%.

  19. Measurement of leaf relative water content by infrared reflectance

    NASA Technical Reports Server (NTRS)

    Hunt, E. Raymond, Jr.; Rock, Barrett N.; Nobel, Park S.

    1987-01-01

    From basic considerations and Beer's law, a leaf water content index incorporating reflectances of wavelengths from 0.76 to 0.90 microns and from 1.55 to 1.75 microns was developed that relates leaf reflectance to leaf relative water content. For the leaf succulent, Agave deserti, the leaf water content index was not significantly different from the relative water content for either individual leaves or an entire plant. Also, the relative water contents of intact plants of Encelia farinosa and Hilaria rigida in the field were estimated by the leaf water content index; variations in the proportion of living to dead leaf area could cause large errors in the estimate of relative water content. Thus, the leaf water content index may be able to estimate average relative water content of canopies when TM4 and TM5 are measured at a known relative water content and fraction of dead leaf material.

  20. Measuring water content by neutron thermalization

    SciTech Connect

    Buchanan, R.J.

    1992-01-21

    This patent describes an apparatus for measuring water content of a substance. It comprises a vessel for receiving the substance; sensor means for sensing thermalized neutrons; a thermal neutron absorber disposed around the vessel and the sensor means; means for emitting fast neutrons through the thermal neutron absorber into the vessel; and a biological shield encasing the sensor means, the thermal neutron absorber, and the means for emitting and extending around the vessel.

  1. Use of Water Content Reflectometers in Bioinfiltration/Bioretention to Measure Water Movement and Estimate Evapotranspiration - abstract

    EPA Science Inventory

    Most bioinfiltration/bioretention models assume runoff is evenly distributed across the surface area and after the engineered fill media is no longer saturated, the volumetric water content (VWC) is constant throughout the media profile and at field capacity. Four to nine water ...

  2. Use of Water Content Reflectometers in Bioinfiltration/Bioretention to Measure Water Movement and Estimate Evapotranspiration - abstract

    EPA Science Inventory

    Most bioinfiltration/bioretention models assume runoff is evenly distributed across the surface area and after the engineered fill media is no longer saturated, the volumetric water content (VWC) is constant throughout the media profile and at field capacity. Four to nine water ...

  3. Ultraviolet optical constants of water and ammonia ices

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Anderson, R. C.

    1975-01-01

    A method reported by Tempelmeyer and Mills (1968) for the determination of real refractive indices of transparent films was used in the investigation. It was found that the fringe period for a transparent film can be used to approximate the period for a semitransparent film near its extremum. The experimental apparatus is discussed along with details regarding the employed technique. Graphs are presented concerning the refractive index and the absorption coefficients for amorphous water ice and amorphous ammonia ice.

  4. Simulations of dissociation constants in low pressure supercritical water

    NASA Astrophysics Data System (ADS)

    Halstead, S. J.; An, P.; Zhang, S.

    2014-09-01

    This article reports molecular dynamics simulations of the dissociation of hydrochloric acid and sodium hydroxide in water from ambient to supercritical temperatures at a fixed pressure of 250 atm. Corrosion of reaction vessels is known to be a serious problem of supercritical water, and acid/base dissociation can be a significant contributing factor to this. The SPC/e model was used in conjunction with solute models determined from density functional calculations and OPLSAA Lennard-Jones parameters. Radial distribution functions were calculated, and these show a significant increase in solute-solvent ordering upon forming the product ions at all temperatures. For both dissociations, rapidly decreasing entropy of reaction was found to be the controlling thermodynamic factor, and this is thought to arise due to the ions produced from dissociation maintaining a relatively high density and ordered solvation shell compared to the reactants. The change in entropy of reaction reaches a minimum at the critical temperature. The values of pKa and pKb were calculated and both increased with temperature, in qualitative agreement with other work, until a maximum value at 748 K, after which there was a slight decrease.

  5. Electrochemical impedance spectroscopy as an alternative to determine dielectric constant of potatoes at various moisture contents.

    PubMed

    Chee, Grace; Rungraeng, Natthakan; Han, Jung H; Jun, Soojin

    2014-02-01

    The dielectric (DE) properties, specifically the DE constant (ε') and loss factor (ε''), were measured for vacuum-dried and freeze-dried potato samples at a microwave frequency of 2.45 GHz over a range of different moisture contents (MCs) using a DE probe and also a 2-probe electrochemical impedance spectroscopy (EIS). Third-order polynomial models (ε' = f₁(MC); and ε'' = f₂(MC)) at room temperature were developed for regression analysis. Additionally, at various temperatures (T), biphasic 3rd-order polynomial models (ε' = f₁(MC, T); and ε'' = f₂(MC, T)) were obtained to determine ε' and ε'' as a function of MC and T using measured data. The vacuum-dried potato sample showed a good fitness of ε' and ε'' (R² = 0.95 and 0.96, respectively) to the regression model with the range of MCs from 18% to 80% (w/w), while the freeze-dried potato sample showed a good fitness of ε' and ε'' to the 1st-phase regression model with MC < 50% w/w (R² = 0.95 and 0.96, respectively) and the 2nd-phase regression model with MC > 50% w/w (R² = 0.94 to 0.96). EIS measurements were also used to obtain correlation impedances for ε' and ε'' determined by the DE probe method. The resulted regression analysis meets the demands for simple, rapid, and accurate assessment for transient values of ε' and ε'' of food products during dehydration/drying processes. The EIS method was verified to be a successful alternative to direct measurements of ε' and ε''. © 2014 Institute of Food Technologists®

  6. Relative water content of Spruce needles determined by the leaf water content index

    NASA Technical Reports Server (NTRS)

    Hunt, E. Raymond, Jr.; Wong, Sam K. S.; Rock, Barrett N.

    1987-01-01

    Leaf relative water content (RWC) is defined as the volume of water in a leaf divided by the volume at full turgor. Using reflectance factors of wavelengths 0.83 micron and 1.6 microns, a Leaf Water Content Index (LWCI) was derived from the Lambert-Beer Law such that LWCI should equal RWC; LWCI was equal to RWC for Picea pungens, Picea rubens, Liquidambar styraciflua, and Quercus agrifolia. Algebraic manipulation shows that R(1.6)/R(0.83) termed the Moisture Stress Index (MSI), is near-linearly correlated to RWC and to the Equivalent Water Thickness (EWT). Five species tested so far had the same relationship between MSI and EWT, but EWT is not a measure of plant water status.

  7. Relative water content of Spruce needles determined by the leaf water content index

    NASA Technical Reports Server (NTRS)

    Hunt, E. Raymond, Jr.; Wong, Sam K. S.; Rock, Barrett N.

    1987-01-01

    Leaf relative water content (RWC) is defined as the volume of water in a leaf divided by the volume at full turgor. Using reflectance factors of wavelengths 0.83 micron and 1.6 microns, a Leaf Water Content Index (LWCI) was derived from the Lambert-Beer Law such that LWCI should equal RWC; LWCI was equal to RWC for Picea pungens, Picea rubens, Liquidambar styraciflua, and Quercus agrifolia. Algebraic manipulation shows that R(1.6)/R(0.83) termed the Moisture Stress Index (MSI), is near-linearly correlated to RWC and to the Equivalent Water Thickness (EWT). Five species tested so far had the same relationship between MSI and EWT, but EWT is not a measure of plant water status.

  8. Fluoride and bacterial content of bottled water vs tap water.

    PubMed

    Lalumandier, J A; Ayers, L W

    2000-03-01

    Bottled water has become a status symbol and is frequently used in place of tap water. While both waters are considered safe to drink, is either more beneficial in preventing tooth decay and is there a difference in purity? To determine the fluoride level and bacterial content of commercially bottled waters municipal tap water and to compare the results. Comparative study. Cleveland, Ohio. Fifty-seven samples of 5 categories of bottled waters were purchased from local stores. Samples of tap water were collected in sterile containers from the 4 local water processing plants. Fluoride levels were determined by an ion-selective electrode method. Water was cultured quantitatively and levels of bacteria were calculated as colony-forming units (CFUs) per milliliter. Fluoride levels and bacterial counts. Fluoride levels within the range recommended for drinking water by the Ohio Environmental Protection Agency, Cincinnati, 0.80 to 1.30 mg/L, were found in only 3 samples of bottled water tested. The fluoride levels of tap water samples were within 0.04 mg/L of the optimal fluoride level of 1.00 mg/L. The bacterial counts in the bottled water samples ranged from less than 0.01 CFU/mL to 4900 CFUs/mL, including 6 samples with levels substantially above 1000 CFUs/mL. In contrast, bacterial counts in samples of tap water ranged from 0.2 to 2.7 CFUs/mL. Five percent of the bottled water purchased in Cleveland fell within the required fluoride range recommended by the state, compared with 100% of the tap water samples, all of which were also within 0.04 mg/L of the optimal fluoride level of 1.00 mg/L. Use of bottled water based on the assumption of purity can be misguided. Recently, the Environmental Protection Agency, Washington, DC, published a final ruling that requires community water systems to regularly report to the public on the quality of local tap water; there are no similar proposals to determine the quality of bottled water through labeling.

  9. The Determination of Protonation Constants of Peptidomimetic Cyclophanes in Binary Methanol-Water Mixtures

    PubMed Central

    Tomczyk, Danuta; Andrijewski, Grzegorz

    2016-01-01

    The protonation constants of new group of peptidomimetic cyclophanes with valine or phenylalanine moieties incorporated into the macrocyclic skeleton as well as their linear analogues were determined by potentiometric measurements in solutions of methanol-water mixtures at 25°C and constant ionic strength. The influence of cavity size, location of protonation sites, and attached substituents of the macrocyclic ligands on the protonation constants were discussed on the basis of potentiometric measurement as well as H1-NMR results. PMID:27516918

  10. The MODIS Vegetation Canopy Water Content product

    NASA Astrophysics Data System (ADS)

    Ustin, S. L.; Riano, D.; Trombetti, M.

    2008-12-01

    Vegetation water stress drives wildfire behavior and risk, having important implications for biogeochemical cycling in natural ecosystems, agriculture, and forestry. Water stress limits plant transpiration and carbon gain. The regulation of photosynthesis creates close linkages between the carbon, water, and energy cycles and through metabolism to the nitrogen cycle. We generated systematic weekly CWC estimated for the USA from 2000-2006. MODIS measures the sunlit reflectance of the vegetation in the visible, near-infrared, and shortwave infrared. Radiative transfer models, such as PROSPECT-SAILH, determine how sunlight interacts with plant and soil materials. These models can be applied over a range of scales and ecosystem types. Artificial Neural Networks (ANN) were used to optimize the inversion of these models to determine vegetation water content. We carried out multi-scale validation of the product using field data, airborne and satellite cross-calibration. An Algorithm Theoretical Basis Document (ATBD) of the product is under evaluation by NASA. The CWC product inputs are 1) The MODIS Terra/Aqua surface reflectance product (MOD09A1/MYD09A1) 2) The MODIS land cover map product (MOD12Q1) reclassified to grassland, shrub-land and forest canopies; 3) An ANN trained with PROSPECT-SAILH; 4) A calibration file for each land cover type. The output is an ENVI file with the CWC values. The code is written in Matlab environment and is being adapted to read not only the 8 day MODIS composites, but also daily surface reflectance data. We plan to incorporate the cloud and snow mask and generate as output a geotiff file. Vegetation water content estimates will help predicting linkages between biogeochemical cycles, which will enable further understanding of feedbacks to atmospheric concentrations of greenhouse gases. It will also serve to estimate primary productivity of the biosphere; monitor/assess natural vegetation health related to drought, pollution or diseases

  11. Spectrophotometric determination of acidity constants of some anthraquinones and anthrones in methanol-water mixtures.

    PubMed

    Shamsipur, M; Ghasemi, J; Tamaddon, F; Sharghi, H

    1993-05-01

    The acidity constants of some synthetic derivatives of 9,10-anthraquinone and 9-anthrone in methanol-water mixtures at 25 degrees have been determined spectrophotometrically. A linear reverse relationship is observed between pK(a1) of all acids and the mole fraction of methanol. The influence of substituents in the molecular structure on the ionization constants is discussed.

  12. An investigation of the relationship between tree water potential and dielectric constant

    NASA Technical Reports Server (NTRS)

    Mcdonald, Kyle C.; Zimmermann, Reiner; Way, Jobea; Oren, Ram

    1992-01-01

    An experiment that has been performed to verify the relationship between the dielectric constant of several tree species and their respective water potentials is described. The water potential, xylem flow and dielectric properties of five tree species were continuously monitored while simultaneously manipulating canopy transpiration and water status. An analysis of the data recorded during these manipulations is presented. Results of this analysis demonstrate a clear coincidence of change in dielectric constant and water status. The implication of this relationship for the utilization of remotely sensed data to study canopy water relations is explored. Preliminary backscatter modeling results demonstrate that the changes in dielectric constant that occur as a result of changes in water status are significant enough to be observable with microwave radar.

  13. An investigation of the relationship between tree water potential and dielectric constant

    NASA Technical Reports Server (NTRS)

    Mcdonald, Kyle C.; Zimmermann, Reiner; Way, Jobea; Oren, Ram

    1992-01-01

    An experiment that has been performed to verify the relationship between the dielectric constant of several tree species and their respective water potentials is described. The water potential, xylem flow and dielectric properties of five tree species were continuously monitored while simultaneously manipulating canopy transpiration and water status. An analysis of the data recorded during these manipulations is presented. Results of this analysis demonstrate a clear coincidence of change in dielectric constant and water status. The implication of this relationship for the utilization of remotely sensed data to study canopy water relations is explored. Preliminary backscatter modeling results demonstrate that the changes in dielectric constant that occur as a result of changes in water status are significant enough to be observable with microwave radar.

  14. Equilibrium constant of the gamma-sultone and extraction constant of sodium and potassium ions from water into benzene in presence of 18-crown-6 and bromocresol green.

    PubMed

    Kolthoff, Izaak M; Chantooni, Miran K; Jyo, Akinori

    2002-07-03

    An extraction procedure for the spectrophotometric determination of sodium or potassium involving a 1:1:1 metal ion: crown ether: sulfonephthalein dye monoanion ion associate has been described in the literature. In a recent paper from this laboratory the total dye content of the organic phase resulting from partitioning bromocresol green (HBCG) alone between water and benzene was determined from back extraction into an aqueous phosphate buffer. In benzene, bromocresol green is present to a large extent as a colorless lactone form, or gamma-sultone. The sultone equilibrium constant, K(dist) (sultone)=[sultone](o)/[BCG(-)](w)gamma(BCG(-))(w)a(H(+)) was found to be 373+/-42 mol(-1) dm(3). In the present study, sodium was extracted from water into benzene with 18-crown-6 and BCG(-), yielding K(dist) (sultone)=232 mol(-1) dm(3) and the conventional extraction constant, K(ex), of (5.49+/-0.49)x10(3) mol(-2) dm(6). Corresponding values from potassium extraction data are 256 mol(-1) dm(3) and (4.80+/-0.51)x10(6) mol(-2) dm(6), respectively. In the absence of ethanol, the calibration plot of sodium closely followed Beer's law, but that of potassium curved downward, approaching linearity in 15% ethanol. High 18-crown-6, low bromocresol green concentrations are analytically favorable for the extraction of potassium from the 15% aqueous ethanol mixture. All plots from the back-extractions (a measure of the total dye content in the benzene phase) were linear. Ethanol markedly reduced the reagent blank, when C(MCl)=0, as a result of the sultone being partitioned less favorably into benzene.

  15. Comparison of Vegetation Water Content Estimates from Windsat and Modis

    USDA-ARS?s Scientific Manuscript database

    Retrieval of soil moisture content from microwave sensors also returns an estimate of vegetation water content. Remotely sensed indices from optical sensors can be used to estimate canopy water content. For corn and soybean in central Iowa, there are allometric relationships between canopy water c...

  16. Time-domain reflectometry: Simultaneous measurement of soil water content and electrical conductivity with a single probe

    USGS Publications Warehouse

    Dalton, F.N.; Herkelrath, W.N.; Rawlins, D.S.; Rhoades, J.D.

    1984-01-01

    Two parallel metallic rods were used as a wave guide to measure the dielectric constant and electrical conductivity of soils having different electrical conductivities but the same water content. Measurements showed that the two parameters were sufficiently independent to permit simultaneous determinations of water content and bulk electrical conductivity.

  17. [Estimation of vegetation water content from Landsat 8 OLI data].

    PubMed

    Zheng, Xing-ming; Ding, Yan-ling; Zhao, Kai; Jiang, Tao; Li, Xiao-feng; Zhang, Shi-yi; Li, Yang-yang; Wu, Li-li; Sun, Jian; Ren, Jian-hua; Zhang, Xuan-xuan

    2014-12-01

    The present paper aims to analyze the capabilities and limitations for retrieving vegetation water content from Landsat8 OLI (Operational Land Imager) sensor-new generation of earth observation program. First, the effect of soil background on canopy reflectance and the sensitive band to vegetation water content were analyzed based on simulated dataset from ProSail model. Then, based on vegetation water indices from Landsat8 OLI and field vegetation water content during June 1 2013 to August 14 2013, the best vegetation water index for estimating vegetation water content was found through comparing 12 different indices. The results show that: (1) red, near infrared and two shortwave infrared bands of OLI sensor are sensitive to the change in vegetation water content, and near infrared band is the most sensitive one; (2) At low vegetation coverage, solar radiation reflected by soil background will reach to spectral sensor and influence the relationship between vegetation water index and vegetation water content, and simulation results from ProSail model also show that soil background reflectance has a significant impact on vegetation canopy reflectance in both wet and dry soil conditions, so the optimized soil adjusted vegetation index (OSAVI) was used in this paper to remove the effect of soil background on vegetation water index and improve its relationship with vegetation water content; (3) for the 12 vegetation water indices, the relationship between MSI2 and vegetation water content is the best with the R-square of 0.948 and the average error of vegetation water content is 0.52 kg · m(-2); (4) it is difficult to estimate vegetation water content from vegetation water indices when vegetation water content is larger than 2 kg · m(-2) due to spectral saturation of these indices.

  18. An empirical model for the complex dielectric permittivity of soils as a function of water content

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Chmugge, T. J.

    1978-01-01

    The recent measurements on the dielectric properties of soils shows that the variation of dielectric constant with moisture content depends on soil types. The observed dielectric constant increases only slowly with moisture content up to a transition point. Beyond the transition it increases rapidly with moisture content. The moisture value of transition region was found to be higher for high clay content soils than for sandy soils. Many mixing formulas were compared with, and were found incompatible with, the measured dielectric variations of soil-water mixtures. A simple empirical model was proposed to describe the dielectric behavior of ths soil-water mixtures. The relationship between transition moisture and wilting point provides a means of estimating soil dielectric properties on the basis of texture information.

  19. Determining Water Content of Geologic Materials Using Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Milliken, R. E.; Mustard, J. F.

    2004-03-01

    TGA data and reflectance spectra are used to track changes in water absorptions as a function of absolute water content. Calculating band depth areas of absorptions in VIS-NIR data may prove useful for quantifying the water content of Mars' surface.

  20. Molecular dynamics simulation of vapour-liquid nucleation of water with constant energy

    NASA Astrophysics Data System (ADS)

    Duška, Michal; Němec, Tomáš; Hrubý, Jan; Vinš, Václav; Planková, Barbora

    2015-05-01

    The paper describes molecular dynamics study of nucleation of water in NVE ensemble. The numerical simulation was performed with the DL_POLY. The metastable steam consisting of 10976 water molecules with TIP4P/2005 potential was driven on the desired energy level by a simulation at constant temperature, and then the nucleation at constant energy was studied for several tens of nanoseconds, which was sufficient for clusters to evolve at hundred molecules size. The results were compared with the previously published results and the classical nucleation theory predictions.

  1. The dielectric constant of water. Computer simulations with the MCY potential

    NASA Astrophysics Data System (ADS)

    Neumann, Martin

    1985-06-01

    Despite the sizable literature on computer simulations of water and aqueous solutions, very little is known about one of the most interesting properties of water, namely its dielectric constant. In this paper it is demonstrated that the methodological as well as technological problems that have hitherto impeded the calculation of dielectric properties of realistic model systems have now been overcome. Using a small dedicated array processor, a series of extensive simulations with the MCY (Matsuoka-Clementi-Yoshimine) potential for water have been performed in reaction field geometry, and it is shown that consistent (i.e., free from boundary effects) and accurate results may be obtained for the full frequency-dependent dielectric constant, from the static up to the submillimeter range. At the same time it is found that the rather popular MCY model is not able to satisfactorily reproduce the dielectric properties of real water: Both the static dielectric constant and the principal dielectric relaxation time are much lower than the experimental values, and the temperature dependence of the Kirkwood g factor has the wrong sign. It is concluded that in the future the calculation of the dielectric constant, being a measure of orientational correlations between molecules, will play an important part in assessing the reliability of model potentials for water.

  2. Ancient climate from deuterium content of water in volcanic glass

    NASA Astrophysics Data System (ADS)

    Friedman, Irving; Gleason, Jim; Warden, Augusta

    Explosive eruptions of rhyolitic tephras may eject ash to great heights where it is distributed by winds over large areas. This ash, within a few thousand years after deposition, incorporates relatively large amounts of environmental water (up to 3.5 percent by weight) into its glass structure. This secondary hydration water is shown to retain its original deuterium concentration through time, and because the deuterium content of precipitation has been used for climate characterization, the hydration water, which is related to ancient precipitation, can be used as an indication of ancient climates. Samples of water extracted from dated volcanic ash from Iceland, New Zealand, and the western and central United States have been analyzed for deuterium, and the results of these analyses are used to reconstruct elements of climate ranging in age from 885 years to 2.1 million years before present. Based on the analysis of ash samples erupted between 13,000 and 6800 years before present, the climate in northern Nevada, Oregon, western Washington and in western and central Montana has not changed greatly from about 6000 y BP to present, and the climate in western Washington has remained constant from about 13,000 y BP to present. However eastern Washington and western Montana may have been about 2°-6°C cooler at the end of the Pleistocene and early Holocene than the present. The deuterium concentrations of surface waters in the central and western United States appear to have been similar at 0.6 Ma, 0.75 Ma, and 2.1 Ma, but to have differed from the present concentrations in portions of the study area.

  3. Predicting the Reactivity of Hydride Donors in Water: Thermodynamic Constants for Hydrogen

    SciTech Connect

    Connelly, Samantha J.; Wiedner, Eric S.; Appel, Aaron M.

    2015-01-01

    Chemical reactivity of hydride complexes can be predicted by comparing bond strengths for homolytic and heterolytic cleavage of bonds to hydrogen. To determine these bond strengths, thermodynamic constants for H+, H•, H–, and H2 are essential and need to be used uniformly to enable the prediction of reactivity and equilibria. One of the largest challenges is quantifying the stability of solvated H– in water, which is discussed. Due to discrepancies in the literature for the constants used in water, we propose the use of a set of self-consistent constants with convenient standard states. The work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

  4. Computational IR spectroscopy of water: OH stretch frequencies, transition dipoles, and intermolecular vibrational coupling constants

    NASA Astrophysics Data System (ADS)

    Choi, Jun-Ho; Cho, Minhaeng

    2013-05-01

    The Hessian matrix reconstruction method initially developed to extract the basis mode frequencies, vibrational coupling constants, and transition dipoles of the delocalized amide I, II, and III vibrations of polypeptides and proteins from quantum chemistry calculation results is used to obtain those properties of delocalized O-H stretch modes in liquid water. Considering the water symmetric and asymmetric O-H stretch modes as basis modes, we here develop theoretical models relating vibrational frequencies, transition dipoles, and coupling constants of basis modes to local water configuration and solvent electric potential. Molecular dynamics simulation was performed to generate an ensemble of water configurations that was in turn used to construct vibrational Hamiltonian matrices. Obtaining the eigenvalues and eigenvectors of the matrices and using the time-averaging approximation method, which was developed by the Skinner group, to calculating the vibrational spectra of coupled oscillator systems, we could numerically simulate the O-H stretch IR spectrum of liquid water. The asymmetric line shape and weak shoulder bands were quantitatively reproduced by the present computational procedure based on vibrational exciton model, where the polarization effects on basis mode transition dipoles and inter-mode coupling constants were found to be crucial in quantitatively simulating the vibrational spectra of hydrogen-bond networking liquid water.

  5. An empirical model for the complex dielectric permittivity of soils as a function of water content

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Schmugge, T. J.

    1980-01-01

    Recent measurements on the dielectric properties of soils have shown that the variation of dielectric constant with moisture content depends on soil types. The observed dielectric constant increases only slowly with moisture content up to a transition point. Beyond the transition it increases rapidly with moisture content. The moisture value at transition region was found to be higher for high clay content soils than for sandy soils. Many mixing formulas reported in the literature were compared with, and were found incompatible with, the measured dielectric variations of soil-water mixtures. A simple empirical model was proposed to describe the dielectric behavior of the soil-water mixtures. This model employs the mixing of either the dielectric constants or the refraction indices of ice, water, rock, and air, and treats the transition moisture value as an adjustable parameter. The calculated mixture dielectric constants from the model were found to be in reasonable agreement with the measured results over the entire moisture range of 0-0.5 cu cm/cu cm. The transition moistures derived from the model range from 0.16 to 0.33 and are strongly correlated with the wilting points of the soils estimated from their textures. This relationship between transition moisture and wilting point provides a means of estimating soil dielectric properties on the basis of texture information.

  6. An empirical model for the complex dielectric permittivity of soils as a function of water content

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Schmugge, T. J.

    1980-01-01

    Recent measurements on the dielectric properties of soils have shown that the variation of dielectric constant with moisture content depends on soil types. The observed dielectric constant increases only slowly with moisture content up to a transition point. Beyond the transition it increases rapidly with moisture content. The moisture value at transition region was found to be higher for high clay content soils than for sandy soils. Many mixing formulas reported in the literature were compared with, and were found incompatible with, the measured dielectric variations of soil-water mixtures. A simple empirical model was proposed to describe the dielectric behavior of the soil-water mixtures. This model employs the mixing of either the dielectric constants or the refraction indices of ice, water, rock, and air, and treats the transition moisture value as an adjustable parameter. The calculated mixture dielectric constants from the model were found to be in reasonable agreement with the measured results over the entire moisture range of 0-0.5 cu cm/cu cm. The transition moistures derived from the model range from 0.16 to 0.33 and are strongly correlated with the wilting points of the soils estimated from their textures. This relationship between transition moisture and wilting point provides a means of estimating soil dielectric properties on the basis of texture information.

  7. Determination of water content using mass spectrometry

    NASA Technical Reports Server (NTRS)

    Wood, G. M.; Upchurch, B. T.; Hughes, D. B.

    1975-01-01

    Mass spectrometer is used to measure small quantities of water present in different materials. System has been applied in measuring water and gases desorbed from microcircuitry insulation, can also be used with foods, polymeric materials, and organic solvents.

  8. Monitoring of Water Content in Building Materials Using a Wireless Passive Sensor

    PubMed Central

    Stojanović, Goran; Radovanović, Milan; Malešev, Mirjana; Radonjanin, Vlastimir

    2010-01-01

    This paper describes an innovative design of a wireless, passive LC sensor and its application for monitoring of water content in building materials. The sensor was embedded in test material samples so that the internal water content of the samples could be measured with an antenna by tracking the changes in the sensor’s resonant frequency. Since the dielectric constant of water was much higher compared with that of the test samples, the presence of water in the samples increased the capacitance of the LC circuit, thus decreasing the sensor’s resonant frequency. The sensor is made up of a printed circuit board in one metal layer and water content has been determined for clay brick and autoclaved aerated concrete block, both widely used construction materials. Measurements were conducted at room temperature using a HP-4194A Impedance/Gain-Phase Analyzer instrument. PMID:22399880

  9. Monitoring of water content in building materials using a wireless passive sensor.

    PubMed

    Stojanović, Goran; Radovanović, Milan; Malešev, Mirjana; Radonjanin, Vlastimir

    2010-01-01

    This paper describes an innovative design of a wireless, passive LC sensor and its application for monitoring of water content in building materials. The sensor was embedded in test material samples so that the internal water content of the samples could be measured with an antenna by tracking the changes in the sensor's resonant frequency. Since the dielectric constant of water was much higher compared with that of the test samples, the presence of water in the samples increased the capacitance of the LC circuit, thus decreasing the sensor's resonant frequency. The sensor is made up of a printed circuit board in one metal layer and water content has been determined for clay brick and autoclaved aerated concrete block, both widely used construction materials. Measurements were conducted at room temperature using a HP-4194A Impedance/Gain-Phase Analyzer instrument.

  10. Calcium and bromide contents of natural waters

    USGS Publications Warehouse

    Anderson, R.J.; Graf, D.L.; Jones, B.F.

    1966-01-01

    The linear relation observed in a log Ca++ versus log Br - plot for subsurface Cl- waters is attributed to ultrafiltration by shale of sea water and fresh water that have passed through sedimentary rocks since their formation. Reactions between these solutions and sedimentary minerals, particularly dolomitization, must have contributed additional Ca+ + to solution.

  11. Modelling Ontogenetic Changes of Nitrogen and Water Content in Lettuce

    PubMed Central

    SEGINER, IDO; BLEYAERT, PETER; BREUGELMANS, MAAIKE

    2004-01-01

    • Background and Aims It is well established that the nitrogen content of plants, including lettuce, decreases with time. It has also been observed that water content of lettuce increases between planting and harvest. This paper is an attempt at modelling these observations. • Methods An existing dynamic model (Nicolet), designed to predict growth and nitrate content of glasshouse lettuce, is modified to accommodate the ontogenetic changes of reduced-nitrogen and water contents (on a dry matter basis). The decreasing reduced-N content and the increasing water content are mimicked by dividing the originally uniform plant into ‘metabolically active’ tissue and ‘support’ tissue. The ‘metabolic’ tissue is assumed to contain a higher nitrogen content and a lower water content than the ‘support’ tissue. As the plants grow, the ratio of ‘support’ to ‘metabolic’ tissue increases, resulting in an increased mean water content and a decreased reduced-N content. Simulations with the new model are compared with experimental glasshouse data over four seasons. • Key Results The empirical linear relationship between water and reduced-N contents, matches, to a good approximation, the corresponding relationship based on the model. The agreement between the two makes it possible to effectively uncouple the estimation of the ‘ontogenetic’ parameters from the estimation of the other parameters. The growth and nitrate simulation results match the data rather well and are hardly affected by the new refinement. The reduced-N and water contents are predicted much better with the new model. • Conclusion Prediction of nitrogen uptake for the substantial nitrate pool of lettuce depends on the water content. Hence, the modified model may assist in making better fertilization decisions and better estimates of nitrogen leaching. PMID:15294851

  12. Water waves interacting with a current of constant vorticity: estimating the vorticity of the wave field

    NASA Astrophysics Data System (ADS)

    Simon, Bruno; Seez, William; Abid, Malek; Kharif, Christian; Touboul, Julien

    2017-04-01

    During the last ten years, the topic of water waves interacting with sheared current has drawn a lot of attention, since the interaction of water waves with vorticity was recently found to be significant when modeling the propagation of water waves. In this framework, the configuration involving constantly sheared current (indeed a constant vorticity) is of special interst, since the equations remain tractable. In this framework, it is demonstrated that the flow related to water waves can be described by means of potential theory, since the source term in the vorticity equation is proportionnal to the curvature of the current profile (Nwogu, 2009). In the mean time, the community often wonders if this argument is valid, since the existence of a perfectly linearly sheared current is purely theoretical, and the presence of the vorticity within the wave field can be external (through wave generation mechanisms, for instance). Thus, this work is dedicated to investigate the magnitude of the vorticity related to the wave field, in conditions similar to this analytical case of constant vorticity. This approach is based on the comparison of experimental data, and three models. The first model is linear, supposing a constantly seared current and water waves described by potential theory. The second is fully nonlinear, but still supposing that water waves are potential, and finally, the third model is fully nonlinear, but solves the Euler equations, allowing the existence of vorticity related to the waves. The confrontation of these three approaches with the experimental data will allow to quantify the wave-related vorticity within the total flow, and analyze its importance as a function of nonlinearity and vorticity magnitude. ACKNOWLEDGEMENTS The DGA (Direction Générale de l'Armement, France) is acknowledged for its financial support through the ANR grant N°ANR-13-ASTR-0007.

  13. Estimating the vegetation water content using a radar vegetation index

    USDA-ARS?s Scientific Manuscript database

    Vegetation water content is an important biophysical parameter. Here, the Radar Vegetation Index (RVI) based on polarimetric backscatter observations was evaluated for estimating vegetation water content. Analysis utilized a data set obtained by a ground-based multi-frequency polarimetric scatterome...

  14. Remote sensing of soil water content at large scales

    USDA-ARS?s Scientific Manuscript database

    Soil water content at the near surface is a critical parameter for understanding land surface atmosphere interactions, influencing surface energy balances. Using microwave radiometry, an accurate global map of surface soil water content can be generated on a near daily basis. The accuracy of the p...

  15. RESEARCH NOTE Static dielectric constant of the polarizable NCC water model

    NASA Astrophysics Data System (ADS)

    Millot, Jean-Christophe Soetens Marilia T. C. Martins Costa Claude

    The static dielectric constant epsilon0 of the ab initio water model NCC including polarizability (Niesar, U., Corongiu, G., Clementi, E., Kneller, G. R., and Bhattacharya, D. K., 1990, J. phys. Chem., 94, 7949) has been computed by molecular dynamics simulation at 25oC and a density of 1gcm-3. The long range electrostatic interactions are taken into account by the reaction field method. Values of 100 8 and 8ps are found for the static dielectric constant and dielectric relaxation time, respectively.

  16. Effects of "natural" water and "added" water on prediction of moisture content and bulk density of shelled corn from microwave dielectric properties.

    PubMed

    Trabelsi, Samir; Nelson, Stuart O; Lewis, Micah A

    2010-01-01

    Dielectric properties of samples of shelled corn of "natural" water content and those prepared by adding water were measured in free space at microwave frequencies and 23 degrees C. Results of measurements of attenuation, phase shift and dielectric constant and loss factor at 9 GHz show no difference between the samples with "natural" water and those in which water was added artificially. Bulk densities and moisture contents predicted from calibration equations expressed in terms of dielectric properties of both natural and added water samples agreed closely, and standard errors were less than 1% for moisture content and relative error for bulk density was less than 5%.

  17. Linear relation between time constant of oxygen uptake kinetics, total creatine, and mitochondrial content in vitro.

    PubMed

    Glancy, Brian; Barstow, Thomas; Willis, Wayne T

    2008-01-01

    Following the onset of moderate aerobic exercise, the rate of oxygen consumption (J(o)) rises monoexponentially toward the new steady state with a time constant (tau) in the vicinity of 30 s. The mechanisms underlying this delay have been studied over several decades. Meyer's electrical analog model proposed the concept that the tau is given by tau = R(m) x C, where R(m) is mitochondrial resistance to energy transfer, and C is metabolic capacitance, determined primarily by the cellular total creatine pool (TCr = phosphocreatine + creatine). The purpose of this study was to evaluate in vitro the J(o) kinetics of isolated rat skeletal muscle mitochondria at various levels of TCr and mitochondrial protein. Mitochondria were incubated in a medium containing 5.0 mM ATP, TCr pools of 0-1.5 mM, excess creatine kinase, and an ATP-splitting system of glucose + hexokinase (HK). Pyruvate and malate (1 mM each) were present as oxidative substrates. J(o) was measured across time after HK was added to elicit one of two levels of J(o) (40 and 60% of state 3). At TCr levels (in mM) of 0.1, 0.2, 0.3, 0.75, and 1.5, the corresponding tau values (s, means +/- SE) were 22.2 +/- 3.0, 36.3 +/- 2.2, 65.7 +/- 4.3, 168.1 +/- 22.2, and 287.3 +/- 25.9. Thus tau increased linearly with TCr (R(2) = 0.916). Furthermore, the experimentally observed tau varied linearly and inversely with the mitochondrial protein added. These in vitro results consistently conform to the predictions of Meyer's electrical analog model.

  18. Influence of Water Content on Pullout Behaviour of Geogrid

    NASA Astrophysics Data System (ADS)

    Chen, Rong; Song, Yang-yang; Hao, Dong-xue; Gao, Yu-cong

    2017-06-01

    The interaction between geogrid and soil is fundamental and crucial factor on safety and stability of geogrid-reinforced earth structure. Therefore, the interface index between geogrid and soil is of vital importance in the design of reinforced earth structures. The pullout behaviour of geogrid in soil is studied, an experimental investigation is conducted using geogrid in four groups of soil with 20%, 24%, 28%, 32% water contents, which correspond to normal stresses of 50, 100, 200 and 300 kPa respectively. The results indicate that the geogrid embedded in soil mainly represents pullout failure, and the ultimate pullout force is sensitive to water content. It decreases with the increase of the water content firstly. Besides, the water content influences the process of the pullout behaviour. The increase of water content leads to the ultimate pullout force soon.

  19. Accuracy of soil water content estimates from gamma radiation monitoring data

    NASA Astrophysics Data System (ADS)

    Mao, Jie; Huisman, Johan Alexander; Reemt Bogena, Heye; Vereecken, Harry

    2016-04-01

    Terrestrial gamma radiation is known to be sensitive to soil water content, and could be promising for soil water content determination because of the availability of continental-scale gamma radiation monitoring networks. However, the accuracy of soil water content estimates that can be obtained from this type of data is currently unknown. Therefore, the aim of this study is to assess the accuracy of soil water content estimates from measured time series of gamma radiation. For this, four gamma radiation monitoring stations were each equipped with four soil water content sensors at 5 and 15 cm depth to provide reference soil water content measurements. The contributions of terrestrial radiation and secondary cosmic radiation were separated from the total amount of measured gamma radiation by assuming that the long-term contribution of secondary cosmic radiation was constant, and that variations were related to changes in air pressure and incoming neutrons. In addition, precipitation effects related to atmospheric washout of radon progenies to the ground that cause an increase of gamma radiation were considered by excluding time periods with precipitation and time periods less than three hours after precipitation. The estimated terrestrial gamma radiation was related to soil water content using an exponential function with two fit parameters. For daily soil water content estimates, the goodness of fit ranged from R2= 0.21 to 0.48 and the RMSE ranged from 0.048 to 0.117 m3m-3. The accuracy of the soil water content estimates improved considerably when a weekly resolution was used (RMSE ranged from 0.029 to 0.084 m3m-3). Overall, these results indicate that gamma radiation monitoring data can be used to obtain useful soil water content information. The remaining differences between measured and estimated soil water content can at least partly be explained by the fact that the terrestrial gamma radiation is strongly determined by the upper few centimeters of the soil

  20. Tungsten speciation in sulfidic waters: Determination of thiotungstate formation constants and modeling their distribution in natural waters

    NASA Astrophysics Data System (ADS)

    Mohajerin, T. Jade; Helz, George R.; White, Christopher D.; Johannesson, Karen H.

    2014-11-01

    Using UV/VIS spectrophotometry the equilibrium constants for the formation of monothiotungstate, WO3S2- (WO42-+H2S↔WO3S2-+H2O; log K01 = 3.08 ± 0.11), dithiotungstate, WO2S22- (WO3S2-+H2S↔WO2S22-+H2O; log K12 = 3.22 ± 0.22), trithiotungstate, WOS32- (WO2S22-+H2S↔WO3S2-+H2O; log K23 = 2.76 ± 0.10), and tetrathiotungstate, WS42- (WO3S2-+H2S↔WS42-+H2O; log K34 ∼2.36) were determined. The equilibrium constants describing the formation of thiotungstates are approximately two orders of magnitude less than the equilibrium constants for the formation of the analogous thiomolybdates. These equilibrium constants for thiotungstates were used to model tungstate speciation in sulfidic waters. The model predicts that thiotungstate species are negligible in most natural waters, but are likely to be important in circum-neutral, anoxic waters with ⩾0.1 mM S(-II) concentrations. Natural waters that are conducive to thiotungstate formation include the Black Sea, Tyro and Bannock Basins, and porewaters with high rates of sulfate reduction such as those common in salt marshes. Preliminary field investigations indicate that thiotungstate formation may lead to increased W solubility.

  1. Recreational runners with patellofemoral pain exhibit elevated patella water content.

    PubMed

    Ho, Kai-Yu; Hu, Houchun H; Colletti, Patrick M; Powers, Christopher M

    2014-09-01

    Increased bone water content resulting from repetitive patellofemoral joint overloading has been suggested to be a possible mechanism underlying patellofemoral pain (PFP). To date, it remains unknown whether persons with PFP exhibit elevated bone water content. The purpose of this study was to determine whether recreational runners with PFP exhibit elevated patella water content when compared to pain-free controls. Ten female recreational runners with a diagnosis of PFP (22 to 39years of age) and 10 gender, age, weight, height, and activity matched controls underwent chemical-shift-encoded water-fat magnetic resonance imaging (MRI) to quantify patella water content (i.e., water-signal fraction). Differences in bone water content of the total patella, lateral aspect of the patella, and medial aspect of the patella were compared between groups using independent t tests. Compared with the control group, the PFP group demonstrated significantly greater total patella bone water content (15.4±3.5% vs. 10.3±2.1%; P=0.001), lateral patella water content (17.2±4.2% vs. 11.5±2.5%; P=0.002), and medial patella water content (13.2±2.7% vs. 8.4±2.3%; P<0.001). The higher patella water content observed in female runners with PFP is suggestive of venous engorgement and elevated extracellular fluid. In turn, this may lead to an increase in intraosseous pressure and pain. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Active THz inspection of water content in plants

    NASA Astrophysics Data System (ADS)

    Etayo, D.; Iriarte, J. C.; Palacios, I.; Teniente, J.; Ederra, I.; Gonzalo, R.

    2010-04-01

    The THz range offers the possibility of measuring water content. This can be useful in wine industry to control plants water levels and also to decrease irrigation costs. This paper presents a THz imaging system used to characterise water content in leaves using frequency and time domain methods from 0.14 to 0.22 THz. Our results show the possibility of getting useful information out of the preformed measurements.

  3. DEHYDRATION OF LOW WATER CONTENT ETHANOL

    EPA Science Inventory

    Pervaporation has emerged as an economically viable alternative technology for the dehydration of organic solvents, removal of organic compounds from water and organic/organic separations. Development of a membrane system with suitable flux and selectivity characteristics plays a...

  4. DEHYDRATION OF LOW WATER CONTENT ETHANOL

    EPA Science Inventory

    Pervaporation has emerged as an economically viable alternative technology for the dehydration of organic solvents, removal of organic compounds from water and organic/organic separations. Development of a membrane system with suitable flux and selectivity characteristics plays a...

  5. Note: Extraction of hydrogen bond thermodynamic properties of water from dielectric constant and relaxation time data

    NASA Astrophysics Data System (ADS)

    Rastogi, Abhishek; Yadav, Siddharth; Suresh, S. J.

    2011-08-01

    We recently proposed a theory [Suresh, J. Chem. Phys. 113, 9727 (2000)], 10.1063/1.1320822, based on the principles of statistical mechanics, for describing the temperature variation of static dielectric constant of water and the average number of H-bonds per molecule in the liquid phase. The theoretical model contains three parameters; two of them pertain to the energy and entropy changes accompanying bond-formation, and the third (ɛ∞) represents the dielectric constant at a frequency that is sufficiently low for atomic and electronic polarization, but sufficiently high for intermolecular relaxation processes involving the movement of permanent dipole moments to be inoperative. In the absence of a consensus in the literature for the value of ɛ∞ to be used in dielectric constant calculations, it was arbitrarily set to a commonly accepted value of 1.77 (corresponding to refractive index of 1.33). Values for H-bond parameters were then estimated by best fitting model calculations to experimental data for dielectric constant across temperatures ranging from melting to the critical point of water. It is the purpose of the present Note to eliminate the ambiguity on the choice of ɛ∞ and propose refined values for the H-bond parameters.

  6. Dissociation constants of parabens and limiting conductances of their ions in water.

    PubMed

    Kroflič, Ana; Apelblat, Alexander; Bešter-Rogač, Marija

    2012-02-02

    Precise measurements of electrical conductivities of methylparaben, ethylparaben, propylparaben, and butylparaben sodium salts in dilute aqueous solutions were performed from 278.15 to 313.15 K in 5 K intervals. Experimental conductivity data were analyzed applying the Quint-Viallard conductivity equations by taking into account the salt hydrolysis in aqueous solutions. These evaluations yield the limiting conductances of paraben anions and the dissociation constants of the investigated parabens in water. From temperature dependence of dissociation constants, the thermodynamic functions associated with the dissociation process were estimated. It was discovered that the contributions of enthalpy and entropy to the Gibbs free energy are quite similar. The Walden products of paraben anions in water are independent of temperature, indicating that the hydrodynamic radii are not significantly affected by temperature.

  7. Water content and structure in malignant and benign skin tumours

    NASA Astrophysics Data System (ADS)

    Gniadecka, M.; Nielsen, O. F.; Wulf, H. C.

    2003-12-01

    Analysis of the low frequency region of Raman spectra enables determination of water structure. It has been previously demonstrated by various techniques that water content and possibly also the water structure is altered in some malignant tumours. To further elucidate possible change in water structure in tumours we performed NIR FT Raman spectroscopy on biopsies from selected benign and malignant skin tumours (benign: seborrheic keratosis, pigmented nevi; malignant: malignant melanoma, basal cell carcinoma). We did not observe any differences in water content between malignant and benign skin tumours with an exception of seborrheic keratosis, in which the water content was decreased. Increase in the tetrahedral (free) water was found in malignant skin tumours and sun-damaged skin relative to normal young skin and benign skin tumours. This finding may add to the understanding of molecular alterations in cancer.

  8. Spatially resolved dielectric constant of confined water and its connection to the non-local nature of bulk water

    NASA Astrophysics Data System (ADS)

    Schaaf, Christian; Gekle, Stephan

    2016-08-01

    We use molecular dynamics simulations to compute the spatially resolved static dielectric constant of water in cylindrical and spherical nanopores as occurring, e.g., in protein water pockets or carbon nanotubes. For this, we derive a linear-response formalism which correctly takes into account the dielectric boundary conditions in the considered geometries. We find that in cylindrical confinement, the axial component behaves similar as the local density akin to what is known near planar interfaces. The radial dielectric constant shows some oscillatory features when approaching the surface if their radius is larger than about 2 nm. Most importantly, however, the radial component exhibits pronounced oscillations at the center of the cavity. These surprising features are traced back quantitatively to the non-local dielectric nature of bulk water.

  9. Computational analysis of asymmetric water entry of wedge and ship section at constant velocity

    NASA Astrophysics Data System (ADS)

    Rahaman, Md. Mashiur; Ullah, Al Habib; Afroz, Laboni; Shabnam, Sharmin; Sarkar, M. A. Rashid

    2016-07-01

    Water impact problems receive much attention due to their short duration and large unsteady component of hydrodynamic loads. The effect of water entry has several important applications in various aspects of the naval field. Significant attention has been given to various water entry phenomena such as ship slamming, planning hulls, high-speed hydrodynamics of seaplanes, surface-piercing propellers and the interaction of high-speed liquid drops with structural elements. Asymmetric water entry may be caused by various natural phenomena such as weather conditions or strong winds. Since the determination of hydrodynamic impact load plays a vital role in designing safe and effcient vessels, an accurate and reliable prediction method is necessary to investigate asymmetric water entry problems. In this paper, water entry of a two-dimensional wedge and ship section at constant velocity in asymmetric condition will be analysed numerically and the effects of asymmetric impact on the velocity and pressure distribution will be discussed. The finite volume method is employed to solve the dynamic motion of the wedge in two-phase flow. During the water entry, the air and water interface is described implicitly by the volume of fluid (VOF) scheme. The numerical code and method was first validated for symmetric condition by one of the present author is applied for asymmetric wedge and ship section. The free surface, velocity and pressure distribution for asymmetric water entry are investigated and visualized with contour plots at different time steps.

  10. Determination of the Water Content of Snow by Dielectric Measurements

    DTIC Science & Technology

    1992-07-01

    AD- A256 299 R*UIIUIUIIII• 0P Determination of the Water Content of Snow by Dielectric Measurements Paul R. Camp and David R. LaBrecque July 1992 a...kHz to deterrnlne wfether measurements made In this frequency range might prove useful in evaluating the water content of snow. Dielectric heating at...20 kHz proved a very useful means of modifying the water content from 0 to 30% by weight. Six different natural snows were used in these experiments

  11. The Initial Water Content Dependent Swelling Behavior of Clayey Soils

    NASA Astrophysics Data System (ADS)

    Samet Öngen, Ali; Abiddin Erguler, Zeynal

    2015-04-01

    The variation in water content is known as a main controlling parameter for many physical and mechanical behaviors of clayey soils, particularly soils found in arid and semi-arid regions. Expansive soils found in such regions are naturally subjected to many volume increase and decrease cycles within unsaturated zone during rainy and dry periods, and thus these soils constitute severe hazard to low-rise light buildings and infrastructures constructed in shallow unsaturated depths. Although the relationships between swelling parameters (swelling pressure and swelling percent) and soils' physical - index properties have been investigated in details in previous researches, the continuous effect of water content on swelling mechanisms of soils is not yet sufficiently studied. The water content of unsaturated zone naturally fluctuates with changes in both seasonal climatic conditions and increasing in depths, and therefore, swelling parameters of a soil within unsaturated soils should not be represented with only one single value. For achieving accurate understanding of swelling behavior at field condition, soils should be subjected to swelling tests by considering different initial water content conditions. Considering requirement for further understanding in water content dependent swelling behavior of soils, a research program was aimed to investigate the effect of initial water content on swelling behavior of soil materials. For this purpose, soils having wide range of physical properties such as grain size distributions, mineralogical composition and consistency limits were collected from different locations in Turkey. To minimize the effect of dry unit weight on swelling behavior of soils, samples prepared at same dry unit weight (14.6 kN/m3) with various initial water contents ranging from 0% to approximately 37% were subjected to swelling tests by using convenient odometer device. Beside these tests, grain size distribution, Atterberg limits and mineralogical

  12. [Constant fluoridation of drinking water and the incidence of dental caries in children and juveniles (author's transl)].

    PubMed

    Künzel, W

    1980-01-01

    The regular examination of 20,000 children and juveniles aged 6 to 15 (permanent teeth) and some 12.500 three- to eight-year-olds (deciduous teeth) has shown that the incidence of dental caries (DMF/T and df/t indices) is directly dependent upon the constant fluoridation of drinking water (1.0 +/- 0.1 ppm F). The reduction in dental caries observed on both deciduous and permanent teeth as a result of twelve years of fluoridation of drinking water, which was started in Karl-Marx-Stadt in 1959, was followed, because of the necessity to temporarily discontinue the addition of fluorine salts to the drinking water, by a slight increase in caries which could be checked through refluorination. After eighteen years of fluoridation of drinking water, the situation can again be considered to be in equilibrium. The need for proper fluoridation and regular control thereof through analyzing the fluorine content of drinking water is pointed out.

  13. Accuracy of bottled drinking water label content.

    PubMed

    Khan, Nazeer B; Chohan, Arham N

    2010-07-01

    The purpose of the study was to compare the accuracy of the concentration of fluoride (F), calcium (Ca), pH, and total dissolved solids (TDS) levels mentioned on the labels of the various brands of bottled drinking water available in Riyadh, Saudi Arabia. Twenty-one different brands of locally produced non-carbonated (still water) bottled drinking water were collected from the supermarkets of Riyadh. The concentration of F, Ca, TDS, and pH values were noted from the labels of the bottles. The samples were analyzed for concentrations in the laboratory using the atomic absorption spectrophotometer. The mean level of F, Ca, and pH were found as 0.86 ppm, 38.47 ppm, and 7.5, respectively, which were significantly higher than the mean concentration of these elements reported in the labels. Whereas, the mean TDS concentration was found 118.87 ppm, which was significantly lower than the mean reported on the labels. In tropical countries like Saudi Arabia, the appropriate level of F concentration in drinking water as recommended by World Health Organization (WHO) should be 0.6-0.7 ppm. Since the level of F was found to be significantly higher than the WHO recommended level, the children exposed to this level could develop objectionable fluorosis. The other findings, like pH value, concentrations of Ca, and TDS, were in the range recommended by the WHO and Saudi standard limits and therefore should have no obvious significant health implications.

  14. On the calculations of the nuclear spin spin coupling constants in small water clusters

    NASA Astrophysics Data System (ADS)

    Cybulski, Hubert; Pecul, Magdalena; Sadlej, Joanna

    2006-08-01

    The calculations of the nuclear spin-spin coupling constants were carried out for small water clusters (H 2O) n, n = 2-6, 12, and 17, using density functional theory (DFT) and second-order polarization propagator method (SOPPA). A wide range of different standard and modified basis sets was tested to enable the choice of the possibly smallest and most flexible basis set. The changes in the oxygen-proton coupling constants upon the cluster formation between the nuclei involved in hydrogen bonding cover a range of ca. 13 Hz. The range of the calculated changes in intramolecular 1JOH couplings shows that the simple model of rigid water clusters seems to be sufficient to reproduce properly the sign and to estimate the magnitude of the gas-to-liquid shift. The sign of the complexation-induced changes in the intramolecular 2JHH coupling constant is different for molecules with a different coordination number. While the sign is positive for the molecules of the single donor-single acceptor (DA) and single donor-double acceptor (DAA) types, it is negative for the double donor-single acceptor (DDA) molecules. In the four-coordinated double donor-double acceptor (DDAA) molecules the sign of Δ 2JHH varies. The hydrogen-bond transmitted intermolecular coupling constants are substantial: 1hJOH spans the range from 2.8 to 8.4 Hz while 2hJOO varies from -0.6 to 7.5 Hz. The average intermolecular 1hJOH coupling constant decays slowly with the H⋯O distance in the cyclic clusters n = 2-6. The average 2hJOO coupling decreases exponentially with the O⋯O separation for the cyclic clusters n = 2-6.

  15. Comparison of hyperspectral retrievals with vegetation water indices for leaf and canopy water content

    NASA Astrophysics Data System (ADS)

    Hunt, E. Raymond, Jr.; Daughtry, Craig S. T.; Qu, John J.; Wang, Lingli; Hao, Xianjun

    2011-09-01

    Leaf and canopy water contents provide information for leaf area index, vegetation biomass, and wildfire fuel moisture content. Hyperspectral retrievals of leaf and canopy water content are determined from the relationship of spectral reflectance and the specific absorption coefficient of water over the wavelength range of a water absorption feature. Vegetation water indices such as the Normalized Difference Water Index [NDWI = (R850 - R1240)/(R850 + R1240)] and Normalized Difference Infrared Index [NDII = (R850 - R1650)/(R850 + R1650)] may be calculated from multispectral sensors such as Landsat Thematic Mapper, SPOT HRG, or MODIS. Predicted water contents from hyperspectral data were much greater than measured water contents for both leaves and canopies. Furthermore, simulated spectral reflectances from the PROSPECT and SAIL models also had greater retrieved leaf and canopy water contents compared to the inputs. Used simply as an index correlated to leaf and canopy water contents, hyperspectral retrievals had better predictive capability than NDII or NDWI. Atmospheric correction algorithms estimate canopy water content in order to estimate the amount of water vapor. These results indicate that estimated canopy water contents should have a systematic bias, even though this bias does not affect retrieved surface reflectances from hyperspectral data. Field campaigns in a variety of vegetation functional types are needed to calibrate both hyperspectral retrievals and vegetation water indices.

  16. Water content in the Martian mantle: A Nakhla perspective

    NASA Astrophysics Data System (ADS)

    Weis, Franz A.; Bellucci, Jeremy J.; Skogby, Henrik; Stalder, Roland; Nemchin, Alexander A.; Whitehouse, Martin J.

    2017-09-01

    Water contents of the Martian mantle have previously been investigated using Martian meteorites, with several comprehensive studies estimating the water content in the parental melts and mantle source regions of the shergottites and Chassigny. However, no detailed studies have been performed on the Nakhla meteorite. One possible way to determine the water content of a crystallizing melt is to use the water content in nominally anhydrous minerals (NAMs) such as clinopyroxene and olivine. During or after eruption on the surface of a planetary body and during residence in a degassing magma, these minerals may dehydrate. By reversing this process experimentally, original (pre-dehydration) water concentrations can be quantified. In this study, hydrothermal rehydration experiments were performed at 2 kbar and 700 °C on potentially dehydrated Nakhla clinopyroxene crystals. Rehydrated clinopyroxene crystals exhibit water contents of 130 ± 26 (2σ) ppm and are thus similar to values observed in similar phenocrysts from terrestrial basalts. Utilizing clinopyroxene/melt partition coefficients, both the water content of the Nakhla parent melt and mantle source region were estimated. Despite previous assumptions of a relatively dry melt, the basaltic magma crystallizing Nakhla may have had up to 1.42 ± 0.28 (2σ) wt.% H2O. Based on an assumed low degree of partial melting, this estimate can be used to calculate a minimum estimate of the water content for Nakhla's mantle source region of 72 ± 16 ppm. Combining this value with values determined for other SNC mantle sources, by alternative methods, gives an average mantle value of 102 ± 9 (2σ) ppm H2O for the Martian upper mantle throughout geologic time. This value is lower than the bulk water content of Earth's upper mantle (∼250 ppm H2O) but similar to Earth's MORB source (54-330 ppm, average ∼130 ppm H2O).

  17. Effects of “natural” water and “added” water on prediction of moisture content and bulk density of shelled corn from microwave dielectric properties

    USDA-ARS?s Scientific Manuscript database

    Dielectric properties of samples of shelled corn of “natural” water content and those prepared by adding water were measured in free space at microwave frequencies and 23 oC. Results of measurements of attenuation, phase shift and dielectric constant and loss factor at 9 GHz show no difference betw...

  18. Computing the Kirkwood g-Factor by Combining Constant Maxwell Electric Field and Electric Displacement Simulations: Application to the Dielectric Constant of Liquid Water.

    PubMed

    Zhang, Chao; Hutter, Jürg; Sprik, Michiel

    2016-07-21

    In his classic 1939 paper, Kirkwood linked the macroscopic dielectric constant of polar liquids to the local orientational order as measured by the g-factor (later named after him) and suggested that the corresponding dielectric constant at short-range is effectively equal to the macroscopic value just after "a distance of molecular magnitude" [ Kirkwood, J. Chem. Phys., 1939, 7, 911 ]. Here, we show a simple approach to extract the short-ranged Kirkwood g-factor from molecular dynamics (MD) simulation by superposing the outcomes of constant electric field E and constant electric displacement D simulations [ Zhang and Sprik, Phys. Rev. B: Condens. Matter Mater. Phys., 2016, 93, 144201 ]. Rather than from the notoriously slow fluctuations of the dipole moment of the full MD cell, the dielectric constant can now be estimated from dipole fluctuations at short-range, accelerating the convergence. Exploiting this feature, we computed the bulk dielectric constant of liquid water modeled in the generalized gradient approximation (PBE) to density functional theory and found it to be at least 40% larger than the experimental value.

  19. High Ice Water Content: DC-8 Aeronautics Campaign

    NASA Image and Video Library

    2015-09-10

    During the month of August, NASA’s DC-8 completed flights in Florida aimed at collecting data on high-altitude crystals for the High Ice Water Content (HIWC) mission. High ice water content can be found within large convective storms and can result in aircraft engines losing power or not functioning properly. Researchers will use the data to develop technology that can be used onboard commercial aircraft to avoid high ice water content conditions and provide a safer flight for passengers. This video gives an inside look at the HIWC mission, including research done in and around Hurricane Danny, as well as a look at the instruments being used onboard the research aircraft. Researchers and pilots onboard worked with satellite information from the ground to find regions of high ice water content within the convective systems.

  20. QSPR prediction of the hydroxyl radical rate constant of water contaminants.

    PubMed

    Borhani, Tohid Nejad Ghaffar; Saniedanesh, Mohammadhossein; Bagheri, Mehdi; Lim, Jeng Shiun

    2016-07-01

    In advanced oxidation processes (AOPs), the aqueous hydroxyl radical (HO) acts as a strong oxidant to react with organic contaminants. The hydroxyl radical rate constant (kHO) is important for evaluating and modelling of the AOPs. In this study, quantitative structure-property relationship (QSPR) method is applied to model the hydroxyl radical rate constant for a diverse dataset of 457 water contaminants from 27 various chemical classes. The constricted binary particle swarm optimization and multiple-linear regression (BPSO-MLR) are used to obtain the best model with eight theoretical descriptors. An optimized feed forward neural network (FFNN) is developed to investigate the complex performance of the selected molecular parameters with kHO. Although the FFNN prediction results are more accurate than those obtained using BPSO-MLR, the application of the latter is much more convenient. Various internal and external validation techniques indicate that the obtained models could predict the logarithmic hydroxyl radical rate constants of a large number of water contaminants with less than 4% absolute relative error. Finally, the above-mentioned proposed models are compared to those reported earlier and the structural factors contributing to the AOP degradation efficiency are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Osmosis-induced water uptake by Eurobitum bituminized radioactive waste and pressure development in constant volume conditions

    NASA Astrophysics Data System (ADS)

    Mariën, A.; Mokni, N.; Valcke, E.; Olivella, S.; Smets, S.; Li, X.

    2013-01-01

    The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at the Belgian Nuclear Research Center SCK•CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluña, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO3 leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography (μCT) and Environmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to values that can be (in theory) as high as 42.8 MPa, being the osmotic pressure of a saturated NaNO3 solution. After about four years of hydration in nearly constant volume water uptake tests, pressures up to 20 MPa are measured. During this hydration period only the outer layers with a thickness of 1-2 mm were hydrated (as derived from μCT and ESEM analyses), and only about 10-20% of the initial NaNO3 content was released by the samples. In the studied test

  2. Drinking water for stone formers: is the calcium content relevant?

    PubMed

    Jaeger, P; Portmann, L; Jacquet, A F; Burckhardt, P

    1984-01-01

    Stone formers are often told to select a drinking water with low Ca content. To see whether this measure has a rational biochemical background, 4 Ca hyperabsorbers were asked to drink, first tap water ad libitum, then 2 liters/day of tap water, then 2 liters/day of a low Ca water (A) and finally 2 liters/day of a high Ca water (B). On A, subjects were normocalciuric but hyperoxaluric; whereas on B, they were markedly hypercalciuric but normooxaluric. Therefore, Ca . Ox concentration products were similar on B and A. However, on A as well as on B, Ca . Ox products were much lower than on tap water ad libitum due to the high fluid intake which had thus been imposed. It is concluded that, in the prevention of the recurrence of nephrolithiasis, 'have a high fluid intake' is probably a more relevant advice than 'select a water with a particularly low Ca content'.

  3. Spectrophotometric determination of acidity constants of alizarine red S in water, water-Brij-35 and water-SDS micellar media solutions.

    PubMed

    Niazi, Ali; Ghalie, Mohammad; Yazdanipour, Ateesa; Ghasemi, Jahanbakhsh

    2006-06-01

    The acidity constants of Alizarine Red S in water, water-Brij-35 and water-SDS micellar media solutions at 25 degrees C and an ionic strength of 0.1 M have been determined spectrophotometrically. To evaluate the pH-absorbance data, a resolution method based on the combination of soft- and hard-modeling is applied. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program applied for determination of acidity constants. Results show that the pKa values of Alizarine Red S are influenced as the percentages of a neutral and an anionic surfactant such as Brij-35 and SDS, respectively, added to the solution of this reagent. Effect of surfactant on acidity constants and pure spectrum of each component are also discussed.

  4. Spectrophotometric determination of acidity constants of Alizarine Red S in water, water-Brij-35 and water-SDS micellar media solutions

    NASA Astrophysics Data System (ADS)

    Niazi, Ali; Ghalie, Mohammad; Yazdanipour, Ateesa; Ghasemi, Jahanbakhsh

    2006-06-01

    The acidity constants of Alizarine Red S in water, water-Brij-35 and water-SDS micellar media solutions at 25 °C and an ionic strength of 0.1 M have been determined spectrophotometrically. To evaluate the pH-absorbance data, a resolution method based on the combination of soft- and hard-modeling is applied. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program applied for determination of acidity constants. Results show that the p Ka values of Alizarine Red S are influenced as the percentages of a neutral and an anionic surfactant such as Brij-35 and SDS, respectively, added to the solution of this reagent. Effect of surfactant on acidity constants and pure spectrum of each component are also discussed.

  5. System Regulates the Water Contents of Fuel-Cell Streams

    NASA Technical Reports Server (NTRS)

    Vasquez, Arturo; Lazaroff, Scott

    2005-01-01

    An assembly of devices provides for both humidification of the reactant gas streams of a fuel cell and removal of the product water (the water generated by operation of the fuel cell). The assembly includes externally-sensing forward-pressure regulators that supply reactant gases (fuel and oxygen) at variable pressures to ejector reactant pumps. The ejector supply pressures depend on the consumption flows. The ejectors develop differential pressures approximately proportional to the consumption flow rates at constant system pressure and with constant flow restriction between the mixer-outlet and suction ports of the ejectors. For removal of product water from the circulating oxygen stream, the assembly includes a water/gas separator that contains hydrophobic and hydrophilic membranes. The water separator imposes an approximately constant flow restriction, regardless of the quality of the two-phase flow that enters it from the fuel cell. The gas leaving the water separator is nearly 100 percent humid. This gas is returned to the inlet of the fuel cell along with a quantity of dry incoming oxygen, via the oxygen ejector, thereby providing some humidification.

  6. Evaluation and comparison of diffusion MR methods for measuring apparent transcytolemmal water exchange rate constant

    NASA Astrophysics Data System (ADS)

    Tian, Xin; Li, Hua; Jiang, Xiaoyu; Xie, Jingping; Gore, John C.; Xu, Junzhong

    2017-02-01

    Two diffusion-based approaches, CG (constant gradient) and FEXI (filtered exchange imaging) methods, have been previously proposed for measuring transcytolemmal water exchange rate constant kin, but their accuracy and feasibility have not been comprehensively evaluated and compared. In this work, both computer simulations and cell experiments in vitro were performed to evaluate these two methods. Simulations were done with different cell diameters (5, 10, 20 μm), a broad range of kin values (0.02-30 s-1) and different SNR's, and simulated kin's were directly compared with the ground truth values. Human leukemia K562 cells were cultured and treated with saponin to selectively change cell transmembrane permeability. The agreement between measured kin's of both methods was also evaluated. The results suggest that, without noise, the CG method provides reasonably accurate estimation of kin especially when it is smaller than 10 s-1, which is in the typical physiological range of many biological tissues. However, although the FEXI method overestimates kin even with corrections for the effects of extracellular water fraction, it provides reasonable estimates with practical SNR's and more importantly, the fitted apparent exchange rate AXR showed approximately linear dependence on the ground truth kin. In conclusion, either CG or FEXI method provides a sensitive means to characterize the variations in transcytolemmal water exchange rate constant kin, although the accuracy and specificity is usually compromised. The non-imaging CG method provides more accurate estimation of kin, but limited to large volume-of-interest. Although the accuracy of FEXI is compromised with extracellular volume fraction, it is capable of spatially mapping kin in practice.

  7. Evaluation and comparison of diffusion MR methods for measuring apparent transcytolemmal water exchange rate constant.

    PubMed

    Tian, Xin; Li, Hua; Jiang, Xiaoyu; Xie, Jingping; Gore, John C; Xu, Junzhong

    2017-02-01

    Two diffusion-based approaches, CG (constant gradient) and FEXI (filtered exchange imaging) methods, have been previously proposed for measuring transcytolemmal water exchange rate constant kin, but their accuracy and feasibility have not been comprehensively evaluated and compared. In this work, both computer simulations and cell experiments in vitro were performed to evaluate these two methods. Simulations were done with different cell diameters (5, 10, 20μm), a broad range of kin values (0.02-30s(-1)) and different SNR's, and simulated kin's were directly compared with the ground truth values. Human leukemia K562 cells were cultured and treated with saponin to selectively change cell transmembrane permeability. The agreement between measured kin's of both methods was also evaluated. The results suggest that, without noise, the CG method provides reasonably accurate estimation of kin especially when it is smaller than 10s(-1), which is in the typical physiological range of many biological tissues. However, although the FEXI method overestimates kin even with corrections for the effects of extracellular water fraction, it provides reasonable estimates with practical SNR's and more importantly, the fitted apparent exchange rate AXR showed approximately linear dependence on the ground truth kin. In conclusion, either CG or FEXI method provides a sensitive means to characterize the variations in transcytolemmal water exchange rate constant kin, although the accuracy and specificity is usually compromised. The non-imaging CG method provides more accurate estimation of kin, but limited to large volume-of-interest. Although the accuracy of FEXI is compromised with extracellular volume fraction, it is capable of spatially mapping kin in practice.

  8. Towards mapping attenuation and water content in the Transition Zone

    NASA Astrophysics Data System (ADS)

    Savage, B. K.

    2013-12-01

    The mantle transition zone is suggested to play a significant role in water storage due to the high solubility of H2O in transition zone minerals. However, quantifying the water content of the transition zone has proven difficult. Previous investigations of the transition zone using a variety of techniques have identified variations in water content globally, associated melt at 400 km, and variable thickness. The resulting water distribution models indicate substantially different Earth models and subsequent seismic responses. Water enhances attenuation with minimal change to seismic wave speed in the transition zone. Taken in combination with correlated temperature induced wave speed / attenuation reductions, the water content and temperature in the transition zone can be inferred. Using upper mantle seismic phases that propagate within the transition zone, we can isolate the effects of attenuation, or anelasticity, and seismic wave speeds. Synthetic seismograms at high frequency, around 1 Hz, from models with a "wet" transition zone show a distinct amplitude reduction and phase delay. Conversely, models with melt on top of the transition zone produce a delayed, secondary arrival with an upper mantle moveout velocity. These diagnostic arrivals, based on synthetic seismic responses, are best identified at the end of the triplicated 660 km branch. Full modeling of the seismic phases from the transition zone will enable a mapping of water content and temperature, while deciphering how water is distributed and transported throughout the mantle.

  9. The mineral content of tap water in United States households

    USDA-ARS?s Scientific Manuscript database

    The composition of tap water contributes to dietary intake of minerals. The USDA’s Nutrient Data Laboratory (NDL) conducted a study of the mineral content of residential tap water, to generate current data for the USDA National Nutrient Database. Sodium, potassium, calcium, magnesium, iron, copper...

  10. Remote Sensing of Vegetation Nitrogen Content for Spatially Explicit Carbon and Water Cycle Estimation

    NASA Astrophysics Data System (ADS)

    Zhang, Y. L.; Miller, J. R.; Chen, J. M.

    2009-05-01

    Foliage nitrogen concentration is a determinant of photosynthetic capacity of leaves, thereby an important input to ecological models for estimating terrestrial carbon and water budgets. Recently, spectrally continuous airborne hyperspectral remote sensing imagery has proven to be useful for retrieving an important related parameter, total chlorophyll content at both leaf and canopy scales. Thus remote sensing of vegetation biochemical parameters has promising potential for improving the prediction of global carbon and water balance patterns. In this research, we explored the feasibility of estimating leaf nitrogen content using hyperspectral remote sensing data for spatially explicit estimation of carbon and water budgets. Multi-year measurements of leaf biochemical contents of seven major boreal forest species were carried out in northeastern Ontario, Canada. The variation of leaf chlorophyll and nitrogen content in response to various growth conditions, and the relationship between them,were investigated. Despite differences in plant type (deciduous and evergreen), leaf age, stand growth conditions and developmental stages, leaf nitrogen content was strongly correlated with leaf chlorophyll content on a mass basis during the active growing season (r2=0.78). With this general correlation, leaf nitrogen content was estimated from leaf chlorophyll content at an accuracy of RMSE=2.2 mg/g, equivalent to 20.5% of the average measured leaf nitrogen content. Based on this correlation and a hyperspectral remote sensing algorithm for leaf chlorophyll content retrieval, the spatial variation of leaf nitrogen content was inferred from the airborne hyperspectral remote sensing imagery acquired by Compact Airborne Spectrographic Imager (CASI). A process-based ecological model Boreal Ecosystem Productivity Simulator (BEPS) was used for estimating terrestrial carbon and water budgets. In contrast to the scenario with leaf nitrogen content assigned as a constant value without

  11. Effect of gypsum content on soil water retention

    NASA Astrophysics Data System (ADS)

    Moret-Fernández, D.; Herrero, J.

    2015-09-01

    Many gypsiferous soils occur in arid lands, where the water retention capacity of the soil is vital to plant life and crop production. This study investigated the effect of gypsum content on the gravimetric soil water retention curve (WRC). We analyzed calcium carbonate equivalent (CCE), equivalent gypsum content (EG), soil organic carbon content (SOC), and electrical conductivity of 43 samples collected from various horizons in soils in the Ebro Valley, NE Spain. The WRC of the fine earth was determined using the pressure-plate method (pressure heads = 0, -33, -100, -200, -500, and -1500 kPa), and the gravimetric water retention curves were fitted to the unimodal van Genuchten function. Soil gypsum content had a significant effect on water retention. Soils that had high gypsum content made WRC with higher water retention at near saturation conditions, and steeper WRC slopes. The EG threshold at which gypsum content had an effect on WRC was about 40%, and EG was positively and negatively correlated with the α and n parameters of the WRC, respectively.

  12. Soil Water Content Sensor Response to Organic Matter Content under Laboratory Conditions.

    PubMed

    Fares, Ali; Awal, Ripendra; Bayabil, Haimanote K

    2016-08-05

    Studies show that the performance of soil water content monitoring (SWCM) sensors is affected by soil physical and chemical properties. However, the effect of organic matter on SWCM sensor responses remains less understood. Therefore, the objectives of this study are to (i) assess the effect of organic matter on the accuracy and precision of SWCM sensors using a commercially available soil water content monitoring sensor; and (ii) account for the organic matter effect on the sensor's accuracy. Sand columns with seven rates of oven-dried sawdust (2%, 4%, 6%, 8%, 10%, 12% and 18% v/v, used as an organic matter amendment), thoroughly mixed with quartz sand, and a control without sawdust were prepared by packing quartz sand in two-liter glass containers. Sand was purposely chosen because of the absence of any organic matter or salinity, and also because sand has a relatively low cation exchange capacity that will not interfere with the treatment effect of the current work. Sensor readings (raw counts) were monitored at seven water content levels (0, 0.02, 0.04, 0.08, 0.12, 0.18, 0.24, and 0.30 cm³ cm(-3)) by uniformly adding the corresponding volumes of deionized water in addition to the oven-dry one. Sensor readings were significantly (p < 0.05) affected by the organic matter level and water content. Sensor readings were strongly correlated with the organic matter level (R² = 0.92). In addition, the default calibration equation underestimated the water content readings at the lower water content range (<0.05 cm³ cm(-3)), while it overestimated the water content at the higher water content range (>0.05 cm³ cm(-3)). A new polynomial calibration equation that uses raw count and organic matter content as covariates improved the accuracy of the sensor (RMSE = 0.01 cm³ cm(-3)). Overall, findings of this study highlight the need to account for the effect of soil organic matter content to improve the accuracy and precision of the tested sensor under different soils and

  13. Soil Water Content Sensor Response to Organic Matter Content under Laboratory Conditions

    PubMed Central

    Fares, Ali; Awal, Ripendra; Bayabil, Haimanote K.

    2016-01-01

    Studies show that the performance of soil water content monitoring (SWCM) sensors is affected by soil physical and chemical properties. However, the effect of organic matter on SWCM sensor responses remains less understood. Therefore, the objectives of this study are to (i) assess the effect of organic matter on the accuracy and precision of SWCM sensors using a commercially available soil water content monitoring sensor; and (ii) account for the organic matter effect on the sensor’s accuracy. Sand columns with seven rates of oven-dried sawdust (2%, 4%, 6%, 8%, 10%, 12% and 18% v/v, used as an organic matter amendment), thoroughly mixed with quartz sand, and a control without sawdust were prepared by packing quartz sand in two-liter glass containers. Sand was purposely chosen because of the absence of any organic matter or salinity, and also because sand has a relatively low cation exchange capacity that will not interfere with the treatment effect of the current work. Sensor readings (raw counts) were monitored at seven water content levels (0, 0.02, 0.04, 0.08, 0.12, 0.18, 0.24, and 0.30 cm3 cm−3) by uniformly adding the corresponding volumes of deionized water in addition to the oven-dry one. Sensor readings were significantly (p < 0.05) affected by the organic matter level and water content. Sensor readings were strongly correlated with the organic matter level (R2 = 0.92). In addition, the default calibration equation underestimated the water content readings at the lower water content range (<0.05 cm3 cm−3), while it overestimated the water content at the higher water content range (>0.05 cm3 cm−3). A new polynomial calibration equation that uses raw count and organic matter content as covariates improved the accuracy of the sensor (RMSE = 0.01 cm3 cm−3). Overall, findings of this study highlight the need to account for the effect of soil organic matter content to improve the accuracy and precision of the tested sensor under different soils and

  14. Time lapse imaging of water content with geoelectrical methods: on the interest of working with absolute water content data

    NASA Astrophysics Data System (ADS)

    Dumont, Gaël; Pilawski, Tamara; Robert, Tanguy; Hermans, Thomas; Garré, Sarah; Nguyen, Frederic

    2016-04-01

    The electrical resistivity tomography is a suitable method to estimate the water content of a waste material and detect changes in water content. Various ERT profiles, both static data and time-lapse, where acquired on a landfill during the Minerve project. In the literature, the relative change of resistivity (Δρ/ρ) is generally computed. For saline or heat tracer tests in the saturated zone, the Δρ/ρ can be easily translated into pore water conductivity or underground temperature changes (provided that the initial salinity or temperature condition is homogeneous over the ERT panel extension). For water content changes in the vadose zone resulting of an infiltration event or injection experiment, many authors also work with the Δρ/ρ or relative changes of water content Δθ/θ (linked to the change of resistivity through one single parameter: the Archie's law exponent "m"). This parameter is not influenced by the underground temperature and pore fluid conductivity (ρ¬w) condition but is influenced by the initial water content distribution. Therefore, you never know if the loss of Δθ/θ signal is representative of the limit of the infiltration front or more humid initial condition. Another approach for the understanding of the infiltration process is the assessment of the absolute change of water content (Δθ). This requires the direct computation of the water content of the waste from the resistivity data. For that purpose, we used petrophysical laws calibrated with laboratory experiments and our knowledge of the in situ temperature and pore fluid conductivity parameters. Then, we investigated water content changes in the waste material after a rainfall event (Δθ= Δθ/θ* θ). This new observation is really representatives of the quantity of water infiltrated in the waste material. However, the uncertainty in the pore fluid conductivity value may influence the computed water changes (Δθ=k*m√(ρw) ; where "m" is the Archie's law exponent

  15. Dependence of seismoelectric amplitudes on water content - a field study

    NASA Astrophysics Data System (ADS)

    Strahser, M. H. P.; Matthey, P.-D.; Jouniaux, L.; Sailhac, P.

    2009-04-01

    In porous saturated media, seismic compressional waves can cause seismoelectric and seismoelectromagnetic signals through electrokinetic coupling. It has been observed that these measureable signals also occur in partially saturated media, but the theory is largely unknown for these circumstances. Seismoelectromagnetic tomography is expected to combine the sensitivity of electrical properties to water-content and permeability, to the high spatial resolution of seismic surveys. A better understanding of the physical processes and a reliable quantification of the conversion between seismic and electric energy are necessary and need to take into account the effect of water-content, especially for shallow subsurface investigations. In order to quantify seismoelectric signals with changing water content, we repeated seismoelectric and seismic measurements on the same profile in the Vosges Mountains during several months. The electrical resistivity was also monitored to take into account the water-content variations. We show that an exponential relation can be established between the seismoelectric amplitudes normalized with the seismic amplitudes and the resistivity which in turn is related to the saturation: Increasing resistivity (decreasing water content) leads to decreasing normalized seismoelectric amplitudes. These results imply that the electrokinetic coefficient should increase with water-saturation, as measured in laboratory, but not predicted by theory. This work was funded by CNRS and Université Louis Pasteur de Strasbourg.

  16. The water, deuterium, gas and uranium content of tektites

    USGS Publications Warehouse

    Friedman, I.

    1958-01-01

    The water content, deuterium concentration of the water, total gas and uranium contents were determined on tektite samples and other glass samples from Texas, Australia, Philippine Islands, Java, French Indo-China, Czechoslovakia, Libyan Desert, Billiton Island, Thailand, French West Africa, Peru, and New Mexico. The water content ranges from 0.24 per cent for the Peru tektite, to 0.0002 per cent for a moldavite. The majority of the tektites have less than 0.05 per cent water, and average 0.005 per cent H2O by weight. No other gases were detected, the lower detection limit being about 1 p.p.m. by weight. The deuterium content of the water in tektites is in the same range as that in terrestrial waters, and varies from 0.010 mole per cent to 0.0166 mole per cent deuterium. The uranium content is about from 1 to 3 p.p.m. The possible origin of tektites is discussed. The experimental data presented favour their being originally terrestrial, but produced by some catastrophic event. An extra-terrestrial source is not ruled out. ?? 1958.

  17. Fluoride Content of Bottled Drinking Water in Chennai, Tamilnadu.

    PubMed

    Somasundaram, Sujatha; Ravi, Karunya; Rajapandian, K; Gurunathan, Deepa

    2015-10-01

    The optimum level of fluoride in drinking water is 0.7 to 1.2 ppm. Decreased fluoride concentration leads to increased risk of caries and increased concentration can lead to dental or skeletal fluorosis. One crore liters of water is supplied to Chennai and surrounding areas through pouches and bottles which carters about one third of city population. The aim of this study is to determine the fluoride concentration in top 10 bottled waters in Chennai and to check the accuracy of their labelling. Top selling bottled waters, 6 multinational and 4 Non- multinational brands were selected for the study. Three different batches of each brand were purchased. The labels of the bottled were removed after collecting the details regarding fluoride content. All the bottles were numbered and sent for fluoride content analysis using SPADNS calorimetric method. All the brands and batches which were analysed for the study had less than optimal fluoride content and there is a significant variation in fluoride concentration of each brand and among different batches of same brand bottled waters. The range of fluoride level in tested samples was between 0.27 to 0.59. Only one brand's label had information regarding the fluoride content. Standardization of fluoride levels in bottled waters and labelling of fluoride content should become mandatory.

  18. Fluoride Content of Bottled Drinking Water in Chennai, Tamilnadu

    PubMed Central

    Ravi, Karunya; Rajapandian, K.; Gurunathan, Deepa

    2015-01-01

    Context The optimum level of fluoride in drinking water is 0.7 to 1.2 ppm. Decreased fluoride concentration leads to increased risk of caries and increased concentration can lead to dental or skeletal fluorosis. One crore liters of water is supplied to Chennai and surrounding areas through pouches and bottles which carters about one third of city population. Aim The aim of this study is to determine the fluoride concentration in top 10 bottled waters in Chennai and to check the accuracy of their labelling. Materials and Methods Top selling bottled waters, 6 multinational and 4 Non- multinational brands were selected for the study. Three different batches of each brand were purchased. The labels of the bottled were removed after collecting the details regarding fluoride content. All the bottles were numbered and sent for fluoride content analysis using SPADNS calorimetric method. Results All the brands and batches which were analysed for the study had less than optimal fluoride content and there is a significant variation in fluoride concentration of each brand and among different batches of same brand bottled waters. The range of fluoride level in tested samples was between 0.27 to 0.59. Only one brand’s label had information regarding the fluoride content. Conclusion Standardization of fluoride levels in bottled waters and labelling of fluoride content should become mandatory. PMID:26557612

  19. [Near infrared spectroscopy study on water content in turbine oil].

    PubMed

    Chen, Bin; Liu, Ge; Zhang, Xian-Ming

    2013-11-01

    Near infrared (NIR) spectroscopy combined with successive projections algorithm (SPA) was investigated for determination of water content in turbine oil. Through the 57 samples of different water content in turbine oil scanned applying near infrared (NIR) spectroscopy, with the water content in the turbine oil of 0-0.156%, different pretreatment methods such as the original spectra, first derivative spectra and differential polynomial least squares fitting algorithm Savitzky-Golay (SG), and successive projections algorithm (SPA) were applied for the extraction of effective wavelengths, the correlation coefficient (R) and root mean square error (RMSE) were used as the model evaluation indices, accordingly water content in turbine oil was investigated. The results indicated that the original spectra with different water content in turbine oil were pretreated by the performance of first derivative + SG pretreatments, then the selected effective wavelengths were used as the inputs of least square support vector machine (LS-SVM). A total of 16 variables selected by SPA were employed to construct the model of SPA and least square support vector machine (SPA-LS-SVM). There is 9 as The correlation coefficient was 0.975 9 and the root of mean square error of validation set was 2.655 8 x 10(-3) using the model, and it is feasible to determine the water content in oil using near infrared spectroscopy and SPA-LS-SVM, and an excellent prediction precision was obtained. This study supplied a new and alternative approach to the further application of near infrared spectroscopy in on-line monitoring of contamination such as water content in oil.

  20. Influence of water content on RF and microwave dielectric behavior of foods.

    PubMed

    Nelson, Stuart O; Trabelsi, Samir

    2009-01-01

    The importance of dielectric properties of food materials is discussed with respect to their influence on the heating of materials by radio-frequency and microwave energy and their use for rapid, nondestructive sensing of quality characteristics of such materials. Data are presented graphically showing the frequency and temperature dependence of the dielectric constant and loss factor of wheat, fresh chicken breast meat, several fresh fruits, and apple juice, representing food materials with a wide range of moisture content. The influence of moisture or water content on the dielectric behavior of these materials is discussed, and that behavior is explained in terms of dipolar relaxation and ionic conduction.

  1. Nuclear magnetic shielding constants of liquid water: Insights from hybrid quantum mechanics/molecular mechanics models

    NASA Astrophysics Data System (ADS)

    Kongsted, Jacob; Nielsen, Christian B.; Mikkelsen, Kurt V.; Christiansen, Ove; Ruud, Kenneth

    2007-01-01

    We present a gauge-origin independent method for the calculation of nuclear magnetic shielding tensors of molecules in a structured and polarizable environment. The method is based on a combination of density functional theory (DFT) or Hartree-Fock wave functions with molecular mechanics. The method is unique in the sense that it includes three important properties that need to be fulfilled in accurate calculations of nuclear magnetic shielding constants: (i) the model includes electron correlation effects, (ii) the model uses gauge-including atomic orbitals to give gauge-origin independent results, and (iii) the effect of the environment is treated self-consistently using a discrete reaction-field methodology. The authors present sample calculations of the isotropic nuclear magnetic shielding constants of liquid water based on a large number of solute-solvent configurations derived from molecular dynamics simulations employing potentials which treat solvent polarization either explicitly or implicitly. For both the O17 and H1 isotropic shielding constants the best predicted results compare fairly well with the experimental data, i.e., they reproduce the experimental solvent shifts to within 4ppm for the O17 shielding and 1ppm for the H1 shielding.

  2. Sensitivity of probabilistic MCO water content estimates to key assumptions

    SciTech Connect

    DUNCAN, D.R.

    1999-02-25

    Sensitivity of probabilistic multi-canister overpack (MCO) water content estimates to key assumptions is evaluated with emphasis on the largest non-cladding film-contributors, water borne by particulates adhering to damage sites, and water borne by canister particulate. Calculations considered different choices of damage state degree of independence, different choices of percentile for reference high inputs, three types of input probability density function (pdfs): triangular, log-normal, and Weibull, and the number of scrap baskets in an MCO.

  3. Dielectric properties of low-water-content tissues.

    PubMed

    Smith, S R; Foster, K R

    1985-09-01

    The dielectric properties of two low-water-content tissues, bone marrow and adipose tissue, were measured from 1 kHz to 1 GHz. From 1 kHz to 13 MHz, the measurements were performed using a parallel-plate capacitor method. From 10 MHz to 1 GHz, a reflection coefficient technique using an open-ended coaxial transmission line was employed. The tissue water contents ranged from 1 to almost 70% by weight. The dielectric properties correlate well with the values predicted by mixture theory. Comparison with previous results from high-water-content tissues suggests that bone marrow and adipose tissues contain less motionally altered water per unit dry volume than do the previously studied tissues with lower lipid fractions. The high degree of structural heterogeneity of these tissues was reflected in the large scatter of the data, a source of uncertainty that should be considered in practical applications of the present data.

  4. The conformation-independent QSPR approach for predicting the oxidation rate constant of water micropollutants.

    PubMed

    Ortiz, Erlinda V; Bennardi, Daniel O; Bacelo, Daniel E; Fioressi, Silvina E; Duchowicz, Pablo R

    2017-10-03

    In advanced water treatment processes, the degradation efficiency of contaminants depends on the reactivity of the hydroxyl radical toward a target micropollutant. The present study predicts the hydroxyl radical rate constant in water (k OH) for 118 emerging micropollutants, by means of quantitative structure-property relationships (QSPR). The conformation-independent QSPR approach is employed, together with a large number of 15,251 molecular descriptors derived with the PaDEL, Epi Suite, and Mold2 freewares. The best multivariable linear regression (MLR) models are found with the replacement method variable subset selection technique. The proposed five-descriptor model has the following statistics for the training set: [Formula: see text], RMS train = 0.21, while for the test set is [Formula: see text], RMS test = 0.11. This QSPR serves as a rational guide for predicting oxidation processes of micropollutants.

  5. Physical interpretation of deformation evolvement with water content of ionic polymer-metal composite actuator

    NASA Astrophysics Data System (ADS)

    Zhu, Zicai; Asaka, Kinji; Chang, Longfei; Takagi, Kentaro; Chen, Hualing

    2013-11-01

    Water-based Nafion ionic polymer metal composites (IPMC) exhibit complex deformation properties. In this paper, three eigen stresses, osmotic pressure, total electrostatic stress, and capillary pressure, are investigated with water concentration at various cation concentration levels and compared with the reference hydrostatic pressure, in order to give a physical interpretation on the deformation evolvement with water content. By numerical analysis it is found that under various saturation conditions, the steady-state of the relaxation deformation is dominated by the magnitudes of the osmotic pressure and the total electrostatic stress. When the former is less than the later, IPMC actuator will show a positive steady-state deformation such as the case of Pd-IPMC (water content 20 w.t.%), and vice versa for the case of Au-IPMC (water content 18 w.t.%). With the water content initially decreasing (no more than 4 w.t.%), the relaxation deformation decreases. It is due to the increase of the osmotic pressure and the decrease of the total electrostatic stress. With further decreasing, the relaxation deformation disappears. It is due to the decrease of the cation mobility. And the amplitude of the anode deformation is mainly decided by the effective electrical constant.

  6. Ozonation of pharmaceutical compounds: Rate constants and elimination in various water matrices.

    PubMed

    Javier Benitez, F; Acero, Juan L; Real, Francisco J; Roldán, Gloria

    2009-09-01

    The ozonation of four pharmaceuticals (metoprolol, naproxen, amoxicillin, and phenacetin) in ultra-pure (UP) water was studied in the pH range between 2.5 and 9. The experiments allowed the determination of the apparent rate constants for the reactions between ozone and the selected compounds. The values obtained varied depending on the pH, and ranged between 239 and 1.27x10(4)M(-1) s(-1) for metoprolol; 2.62x10(4) and 2.97x10(5)M(-1)s(-1) for naproxen; 2.31x10(3) and 1.21x10(7)M(-1)s(-1) for amoxicillin; and 215 and 1.57x10(3)M(-1)s(-1) for phenacetin. Due to the acidic nature of these substances, the degree of dissociation of each pharmaceutical was determined at every pH of work, and the specific rate constants of the neutral and ionic species formed were evaluated. Additionally, the simultaneous ozonation of the pharmaceuticals in different water matrices was carried out by considering a groundwater, a surface water from a public reservoir, and three secondary effluents from municipal wastewater treatment plants. The influence of the operating conditions (initial ozone dose, nature of pharmaceuticals and type of water) on the pharmaceuticals elimination efficiency was established, and a kinetic model was proposed for the evaluation of the partial contribution to the global oxidation of both, the direct ozonation reaction and the radical pathway.

  7. Influence of Water Content on the Mechanical Behaviour of Limestone: Role of the Clay Minerals Content

    NASA Astrophysics Data System (ADS)

    Cherblanc, F.; Berthonneau, J.; Bromblet, P.; Huon, V.

    2016-06-01

    The mechanical characteristics of various sedimentary stones significantly depend on the water content, where 70 % loss of their mechanical strengths can be observed when saturated by water. Furthermore, the clay fraction has been shown to be a key factor of their hydro-mechanical behaviour since it governs for instance the hydric dilation. This work aims at investigating the correlations between the clay mineral content and the mechanical weakening experienced by limestones when interacting with water. The experimental characterization focuses on five different limestones that exhibit very different micro-structures. For each of them, we present the determination of clay mineral composition, the sorption isotherm curve and the dependences of tensile and compressive strengths on the water content. It emerges from these results that, first, the sorption behaviour is mainly governed by the amount of smectite layers which exhibit the larger specific area and, second, the rate of mechanical strength loss depends linearly on the sorption capacity. Indeed, the clay fraction plays the role of a retardation factor that delays the appearance of capillary bridges as well as the mechanical weakening of stones. However, no correlation was evidenced between the clay content and the amplitude of weakening. Since the mechanisms whereby the strength decreases with water content are not clearly established, these results would help to discriminate between various hypothesis proposed in the literature.

  8. The deuterium content of water in some volcanic glasses

    USGS Publications Warehouse

    Friedman, I.; Smith, R.L.

    1958-01-01

    The deuterium-hydrogen composition (relative to Lake Michigan water = 0.0) of water extractsd from coexisting perlite and obsidian from eleven different localities was determined. The water content of the obsidians is generally from 0.09 to 0.29 per cent by weight, though two samples from near Olancha, California, contain about 0.92 per cent. The relative deuterium concentration is from -4.6 to -12.3 per cent. The coexisting perlite contains from 2.0 to 3.8 per cent of water with a relative deuterium concentration of -3.1 to -16.6 per cent. The deuterium concentration in the perlites is not related to that in the enclosed obsidian. The deuterium concentration in the perlite water is related to the deuterium concentration of the modern meteoric water and the perlite water contains approximately 4 per cent less deuterium than does the groundwater of the area in which the perlites occur. The above relations hold true for perlites from northern New Mexico, east slope of the Sierra Nevada. California Coast Range, Yellowstone Park, Wyoming, and New Zealand. As the water in the obsidian is unrelated to meteoric water, but the enclosing perlite water is related, we believe that this is evidence for the secondary hydration of obsidian to form high water content perlitic glass. ?? 1958.

  9. [Review of monitoring soil water content using hyperspectral remote sensing].

    PubMed

    Wu, Dai-hui; Fan, Wen-jie; Cui, Yao-kui; Yan, Bin-yan; Xu, Xi-ru

    2010-11-01

    Soil water content is a key parameter in monitoring drought. In recent years, a lot of work has been done on monitoring soil water content based on hyperspectral remotely sensed data both at home and abroad. In the present review, theories, advantages and disadvantages of the monitoring methods using different bands are introduced first. Then the unique advantages, as well as the problems, of the monitoring method with the aid of hyperspectral remote sensing are analyzed. In addition, the impact of soil water content on soil reflectance spectrum and the difference between values at different wavelengths are summarized. This review lists and summarizes the quantitative relationships between soil water content and soil reflectance obtained through analyzing the physical mechanism as well as through statistical way. The key points, advantages and disadvantages of each model are also analyzed and evaluated. Then, the problems in experimental study are pointed out, and the corresponding solutions are proposed. At the same time, the feasibility of removing vegetation effect is discussed, when monitoring soil water content using hyperspectral remote sensing. Finally, the future research trend is prospected.

  10. Predicting the decline in daily maximum transpiration rate of two pine stands during drought based on constant minimum leaf water potential and plant hydraulic conductance.

    PubMed

    Duursma, R A; Kolari, P; Perämäki, M; Nikinmaa, E; Hari, P; Delzon, S; Loustau, D; Ilvesniemi, H; Pumpanen, J; Mäkelä, A

    2008-02-01

    The effect of drought on forest water use is often estimated with models, but comprehensive models require many parameters, and simple models may not be sufficiently flexible. Many tree species, Pinus species in particular, have been shown to maintain a constant minimum leaf water potential above the critical threshold for xylem embolism during drought. In such cases, prediction of the relative decline in daily maximum transpiration rate with decreasing soil water content is relatively straightforward. We constructed a soil-plant water flow model assuming constant plant conductance and daily minimum leaf water potential, but variable conductance from soil to root. We tested this model against independent data from two sites: automatic shoot chamber data and sap flow measurements from a boreal Scots pine (Pinus sylvestris L.) stand; and sap flow measurements from a maritime pine (Pinus pinaster Ait.) stand. To focus on soil limitations to water uptake, we expressed daily maximum transpiration rate relative to the rate that would be obtained in wet soil with similar environmental variables. The comparison was successful, although the maritime pine stand showed carry-over effects of the drought that we could not explain. For the boreal Scots pine stand, daily maximum transpiration was best predicted by water content of soil deeper than 5 cm. A sensitivity analysis revealed that model predictions were relatively insensitive to the minimum leaf water potential, which can be accounted for by the importance of soil resistance of drying soil. We conclude that a model with constant plant conductance and minimum leaf water potential can accurately predict the decline in daily maximum transpiration rate during drought for these two pine stands, and that including further detail about plant compartments would add little predictive power, except in predicting recovery from severe drought.

  11. Leaf Relative Water Content Estimated from Leaf Reflectance and Transmittance

    NASA Technical Reports Server (NTRS)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Remotely sensing the water status of plants and the water content of canopies remain long term goals of remote sensing research. In the research we report here, we used optical polarization techniques to monitor the light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both change nonlinearly. The result show that the nonlinearities cancel in the ratio R/T, which appears linearly related to RWC for RWC less than 90%. The results suggest that potentially leaf water status and perhaps even canopy water status could be monitored starting from leaf and canopy optical measurements.

  12. Sodium Content of Community Water Supplies in California

    PubMed Central

    Steinkamp, Ruth C.; Young, Clarence L.; Nyhus, Dolores; Greenberg, Arnold E.

    1968-01-01

    The amount of sodium ion in water used for ingestion may be critical in effective use of a low sodium dietary regimen. Waters containing not over 20 mg of sodium per liter are provided for in the sodium restricted diets set forth by the American Heart Association. For diets containing more than 500 mg of sodium a day, waters of greater sodium content may be used if proper dietary adjustments are made. While assessment of the long-term average sodium content of a community water supply is difficult, the determined values for sodium lend to classification within range categories. The larger community water supplies in California are presented within several range categories of sodium content. The more commonly used water softeners add sodium to water. The sodium-restricted patient should be cautioned against their use. Similar consideration should probably be given to water supplies of retirement communities where the potential for disorders requiring sodium restriction is greater than in the general population. PMID:5673988

  13. Remote sensing of vegetation water content using shortwave infrared reflectances

    NASA Astrophysics Data System (ADS)

    Hunt, E. Raymond, Jr.; Yilmaz, M. Tugrul

    2007-09-01

    Vegetation water content is an important biophysical parameter for estimation of soil moisture from microwave radiometers. One of the objectives of the Soil Moisture Experiments in 2004 (SMEX04) and 2005 (SMEX05) were to develop and test algorithms for a vegetation water content data product using shortwave infrared reflectances. SMEX04 studied native vegetation in Arizona, USA, and Sonora, Mexico, while SMEX05 studied corn and soybean in Iowa, USA. The normalized difference infrared index (NDII) is defined as (R 850 - R 1650)/(R 800 + R 1650), where R 850 is the reflectance in the near infrared and R1650 is the reflectance in the shortwave infrared. Simulations using the Scattering by Arbitrarily Inclined Leaves (SAIL) model indicated that NDII is sensitive to surface moisture content. From Landsat 5 Thematic Mapper and other imagery, NDII is linear with respect to foliar water content with R2 = 0.81. The regression standard error of the y estimate is 0.094 mm, which is equivalent to about a leaf area index of 0.5 m2 m -2. Based on modeling the dynamic water flow through plants, the requirement for detection of water stress is about 0.01 mm, so detection of water stress may not be possible. However, this standard error is accurate for input into the tau-omega model for soil moisture. Therefore, NDII may be a robust backup algorithm for MODIS as a standard data product.

  14. Gas phase dispersion in compost as a function of different water contents and air flow rates

    NASA Astrophysics Data System (ADS)

    Sharma, Prabhakar; Poulsen, Tjalfe G.

    2009-07-01

    Gas phase dispersion in a natural porous medium (yard waste compost) was investigated as a function of gas flow velocity and compost volumetric water content using oxygen and nitrogen as tracer gases. The compost was chosen because it has a very wide water content range and because it represents a wide range of porous media, including soils and biofilter media. Column breakthrough curves for oxygen and nitrogen were measured at relatively low pore gas velocities, corresponding to those observed in for instance soil vapor extraction systems or biofilters for air cleaning at biogas plants or composting facilities. Total gas mechanical dispersion-molecular diffusion coefficients were fitted from the breakthrough curves using a one-dimensional numerical solution to the advection-dispersion equation and used to determine gas dispersivities at different volumetric gas contents. The results showed that gas mechanical dispersion dominated over molecular diffusion with mechanical dispersion for all water contents and pore gas velocities investigated. Importance of mechanical dispersion increased with increasing pore gas velocity and compost water content. The results further showed that gas dispersivity was relatively constant at high values of compost gas-filled porosity but increased with decreasing gas-filled porosity at lower values of gas-filled porosity. Results finally showed that measurement uncertainty in gas dispersivity is generally highest at low values of pore gas velocity.

  15. Gas phase dispersion in compost as a function of different water contents and air flow rates.

    PubMed

    Sharma, Prabhakar; Poulsen, Tjalfe G

    2009-07-21

    Gas phase dispersion in a natural porous medium (yard waste compost) was investigated as a function of gas flow velocity and compost volumetric water content using oxygen and nitrogen as tracer gases. The compost was chosen because it has a very wide water content range and because it represents a wide range of porous media, including soils and biofilter media. Column breakthrough curves for oxygen and nitrogen were measured at relatively low pore gas velocities, corresponding to those observed in for instance soil vapor extraction systems or biofilters for air cleaning at biogas plants or composting facilities. Total gas mechanical dispersion-molecular diffusion coefficients were fitted from the breakthrough curves using a one-dimensional numerical solution to the advection-dispersion equation and used to determine gas dispersivities at different volumetric gas contents. The results showed that gas mechanical dispersion dominated over molecular diffusion with mechanical dispersion for all water contents and pore gas velocities investigated. Importance of mechanical dispersion increased with increasing pore gas velocity and compost water content. The results further showed that gas dispersivity was relatively constant at high values of compost gas-filled porosity but increased with decreasing gas-filled porosity at lower values of gas-filled porosity. Results finally showed that measurement uncertainty in gas dispersivity is generally highest at low values of pore gas velocity.

  16. Water content and water profiles in skin measured by FTIR and Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lucassen, Gerald W.; Caspers, Peter J.; Puppels, Gerwin J.

    2000-11-01

    We present non-invasive measurements of water content in stratum corneum (SC) by FTIR spectroscopy and water content profiles across the epidermis by Raman microspectroscopy. We apply band fitting to the FTIR spectra to assess changes in SC water content following hydration. While the penetration depth of ATR-FTIR is only a few micrometers, the confocal Raman microspectrometer enables successive collection of Raman spectra at a range of depths below skin surface, with an axial resolution of ca. 5micrometers . Depth resolved water concentration measurements of the epidermis obtained by Raman spectroscopy show clear changes in the water concentration profile as a result of hydration.

  17. Cloud Water Content Sensor for Sounding Balloons and Small UAVs

    NASA Technical Reports Server (NTRS)

    Bognar, John A.

    2009-01-01

    A lightweight, battery-powered sensor was developed for measuring cloud water content, which is the amount of liquid or solid water present in a cloud, generally expressed as grams of water per cubic meter. This sensor has near-zero power consumption and can be flown on standard sounding balloons and small, unmanned aerial vehicles (UAVs). The amount of solid or liquid water is important to the study of atmospheric processes and behavior. Previous sensing techniques relied on strongly heating the incoming air, which requires a major energy input that cannot be achieved on sounding balloons or small UAVs.

  18. Water content or water activity: what rules crispy behavior in bread crust?

    PubMed

    van Nieuwenhuijzen, N H; Primo-Martín, C; Meinders, M B J; Tromp, R H; Hamer, R J; van Vliet, T

    2008-08-13

    A dry crust loses its crispness when water migrates into the crust. It is not clear if it is the amount of water absorbed or the water activity ( a w) that leads to a loss of crispness. The hysteresis effect observed when recording a water sorption isotherm allowed us to study the effects of a w and moisture content separately. All experiments were carried out on model bread crusts made from Soissons bread flour. The effect of water content and water activity on the glass transition of model bread crusts was studied in detail using two complimentary techniques: phase transition analysis (PTA) and nuclear magnetic resonance (NMR). The results were compared with sensory data and results from a puncture test, which provided data on acoustic emission and fracture mechanics during breaking of the crusts. The water content of the crust was found to be decisive for the transition point as measured by PTA and NMR. However, both water content and water activity had an effect on perceived crispness and number of force and sound peaks. From this may be concluded that the distribution of the water in the samples with a history of high water content is more inhomogeneous, which results in crispy and less crispy regions, thus making them overall more crispy than samples with the same water content but higher a w.

  19. Hydrogen in stishovite, with implications for mantle water content.

    PubMed

    Pawley, A R; McMillan, P F; Holloway, J R

    1993-08-20

    Stishovite, the highest pressure polymorph of silicon dioxide, may be an important mineral in some regions of the Earth's mantle. Fourier transform infrared spectroscopy has been used to determine the hydrogen content of synthetic stishovite. The concentration of hydrogen depends on the aluminum content of the sample and reaches a maximum of 549 +/- 23 hydrogen atoms per 10(6) silicon atoms for an Al(2)O(3) content of 1.51 percent by weight. Stishovite could be a storage site for water in deep subducting slabs and in regions of the mantle that are too hot for hydrous minerals to be stable.

  20. Data assimilation with soil water content sensors and pedotransfer functions in soil water flow modeling

    USDA-ARS?s Scientific Manuscript database

    Soil water flow models are based on a set of simplified assumptions about the mechanisms, processes, and parameters of water retention and flow. That causes errors in soil water flow model predictions. Soil water content monitoring data can be used to reduce the errors in models. Data assimilation (...

  1. Influence of drying temperature, water content, and heating rate on gelatinization of corn starches.

    PubMed

    Altay, Filiz; Gunasekaran, Sundaram

    2006-06-14

    The gelatinization properties of starch extracted from corn and waxy corn dried at different temperatures were determined at various water contents and heating rates by differential scanning calorimetry. All gelatinization transition temperatures increased with drying temperature and heating rate. Onset and peak temperatures remained relatively constant, whereas end temperature decreased in the presence of excess water. The gelatinization enthalpy (deltaH(g)) of corn starch decreased with drying temperature at 50% water; however, it remained constant for waxy corn starch. The effects of water content and heating rate on deltaH(g) were dependent on each other. The minimum water levels required for gelatinization of starch extracted from corn dried at 20 and 100 degrees C are 21 and 29%, respectively. The activation energy (E(a)) was calculated using an Arrhenius-type equation and two first-order models; the degree of conversion (alpha) was predicted using a newly proposed model that produced good results for both E(a) and alpha.

  2. Water content of latent fingerprints - Dispelling the myth.

    PubMed

    Kent, Terry

    2016-09-01

    Changing procedures in the handling of rare and precious documents in museums and elsewhere, based on assumptions about constituents of latent fingerprints, have led the author to an examination of available data. These changes appear to have been triggered by one paper using general biological data regarding eccrine sweat production to infer that deposited fingerprints are mostly water. Searching the fingerprint literature has revealed a number of reference works similarly quoting figures for average water content of deposited fingerprints of 98% or more. Whilst accurate estimation is difficult there is no evidence that the residue on fingers could be anything like 98% water, even if there were no contamination from sebaceous glands. Consideration of published analytical data of real fingerprints, and several theoretical considerations regarding evaporation and replenishment rates, indicates a probable initial average water content of a fingerprint, soon after deposition, of 20% or less.

  3. Density fluctuations and dielectric constant of water in low and high density liquid states

    NASA Astrophysics Data System (ADS)

    Lascaris, Erik; Zhang, Cui; Galli, Giulia A.; Franzese, Giancarlo; Stanley, H. Eugene

    2012-02-01

    The hypothesis of a liquid-liquid critical point (LLCP) in the phase diagram of water, though first published many years ago, still remains the subject of a heated debate. According to this hypothesis there exists a critical point near T 244 K, and P 215 MPa, located at the end of a coexistence line between a high density liquid (HDL) and a low density liquid state (LDL). The LLCP lies below the homogenous nucleation temperature of water and it has so far remained inaccessible to experiments. We study a model of water exhibiting a liquid-liquid phase transition (that is a liquid interacting through the ST2 potential) and investigate the properties of dipolar fluctuations as a function of density, in the HDL and LDL. We find an interesting correlation between the macroscopic dielectric constants and the densities of the two liquids in the vicinity of the critical point, and we discuss possible implications for measurements close to the region where the LLCP may be located.

  4. Water dimers in the atmosphere III: equilibrium constant from a flexible potential.

    PubMed

    Scribano, Yohann; Goldman, Nir; Saykally, R J; Leforestier, Claude

    2006-04-27

    We present new results for the water dimer equilibrium constant K(p)(T) in the range 190-390 K, using a flexible potential energy surface fitted to spectroscopical data. The increased numerical complexity due to explicit consideration of the monomer vibrations is handled via an adiabatic (6 + 6)d decoupling between intra- and intermolecular modes. The convergence of the canonical partition function of the dimer is ensured by computing all energy levels up to dissociation for total angular momentum values J = 0-5 and using an extrapolation scheme to higher values. The newly calculated values for K(p)(T) are in very good agreement with available experimental data at room temperature. At higher temperatures, an analysis of the convergence of the partition function reveals that quasi-bound states are likely to contribute to the equilibrium constant. Additional thermodynamical quantities (deltaG, deltaH, deltaS, and C(p)) have also been determined and fit to quadratic expressions a + bT + cT2.

  5. Experimental Solubility Approach to Determine PDMS-Water Partition Constants and PDMS Activity Coefficients.

    PubMed

    Grant, Sharon; Schacht, Veronika J; Escher, Beate I; Hawker, Darryl W; Gaus, Caroline

    2016-03-15

    Freely dissolved aqueous concentration and chemical activity are important determinants of contaminant transport, fate, and toxic potential. Both parameters are commonly quantified using Solid Phase Micro-Extraction (SPME) based on a sorptive polymer such as polydimethylsiloxane (PDMS). This method requires the PDMS-water partition constants, KPDMSw, or activity coefficient to be known. For superhydrophobic contaminants (log KOW >6), application of existing methods to measure these parameters is challenging, and independent measures to validate KPDMSw values would be beneficial. We developed a simple, rapid method to directly measure PDMS solubilities of solid contaminants, SPDMS(S), which together with literature thermodynamic properties was then used to estimate KPDMSw and activity coefficients in PDMS. PDMS solubility for the test compounds (log KOW 7.2-8.3) ranged over 3 orders of magnitude (4.1-5700 μM), and was dependent on compound class. For polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins (PCDDs), solubility-derived KPDMSw increased linearly with hydrophobicity, consistent with trends previously reported for less chlorinated congeners. In contrast, subcooled liquid PDMS solubilities, SPDMS(L), were approximately constant within a compound class. SPDMS(S) and KPDMSw can therefore be predicted for a compound class with reasonable robustness based solely on the class-specific SPDMS(L) and a particular congener's entropy of fusion, melting point, and aqueous solubility.

  6. K-Basins particulate water content, and behavior

    SciTech Connect

    DUNCAN, D.R.

    1999-02-25

    This analysis summarizes the state of knowledge of K-basins spent nuclear fuel oxide (film, particulate or sludge) and its chemically bound water in order to estimate the associated multi-canister overpack (MCO) water inventory and to describe particulate dehydration behavior. This information can be used to evaluate the thermal and chemical history of an MCO and its contents during cold vacuum drying (CVD), shipping, and interim storage.

  7. Critical evaluation and rate constants of chemoselective ligation reactions for stoichiometric conjugations in water.

    PubMed

    Saito, Fumito; Noda, Hidetoshi; Bode, Jeffrey W

    2015-04-17

    Chemoselective ligation reactions have contributed immensely to the development of organic synthesis and chemical biology. However, the ligation of stoichiometric amounts of large molecules for applications such as protein-protein conjugates is still challenging. Conjugation reactions need to be fast enough to proceed under dilute conditions and chemoselective in the presence of unprotected functional groups; the starting materials and products must be stable under the reaction conditions. To compare known ligation reactions for their suitability under these conditions, we determined the second-order rate constants of ligation reactions using peptide substrates with unprotected functional groups. The reaction conditions, the chemoselectivity of the reactions, and the stability of the starting materials and products were carefully evaluated. In some cases, the stability could be improved by modifying the substrate structure. These data obtained under the ligation conditions provide a useful guide to choose an appropriate ligation reaction for synthesis of large molecules by covalent ligation reactions of unprotected substrates in water.

  8. Effect of hydration on the water content of human erythrocytes.

    PubMed Central

    Levin, R L; Cravalho, E G; Huggins, C E

    1976-01-01

    An ideal, hydrated, nondilute pseudobinary salt-protein-water solution model of the RBC intracellular solution has been developed to describe the osmotic behavior of human erythrocytes during freezing and thawing. Because of the hydration of intracellular solutes (mostly cell proteins), our analytical results predict that at least 16.65% of the isotonic cell water content will be retained within RBCs placed in hypertonic solutions. These findings are consistent not only with the experimental measurements of the amount of isotonic cell water retained within RBCs subjected to nonisotonic extracellular solutions (20-32%) but also with the experimental evidence that all of the water within RBCs is solvent water. By modeling the RBC intracellular solution as a hydrated salt-protein-water solution, no anomalous osmotic behavior is apparent. PMID:990394

  9. Vegetation Water Content (VWC) dynamics in during SMAPVEX16

    NASA Astrophysics Data System (ADS)

    Steele-Dunne, S. C.; Polo Bermejo, J.; Judge, J.; Bongiovanni, T. E.; Chakrabarti, S.; Liu, P. W.; Bragdon, J.; Hornbuckle, B. K.

    2016-12-01

    Vegetation water content has a confounding effect on the retrieval of soil moisture from microwave brightness temperatures. The presence of water in the overlying canopy influences the emission from the canopy itself and attenuates the emission from the soil. The purpose of this study is to gain insight into the dynamics of vegetation water content in the context of microwave remote sensing. The key questions are: (1) How is moisture distributed in an agricultural canopy? (2) How does that vertical distribution change in time? (3) How do these dynamics influence the observed brightness temperature? To address these questions, a detailed sampling campaign was undertaken in one corn field and one soybean field at an intensively monitored site near Buckeye, Iowa within the SMAPVEX16 domain. The experiment duration extends from the beginning of IOP1 to the end of IOP2, i.e. from May 18 to August 16 2016. Vegetation sampling was performed on days upon which SMAP had both an ascending and a descending pass. On these days, destructive vegetation samples were generally collected at 6pm and 6pm unless the weather conditions were bad. In addition to measuring the bulk vegetation water content for comparison to the SMAP retrieved VWC, the samples were split into leaves and stems. For the corn plants, leaf moisture content was also measured as a function of height and the stem was cut into 10cm sections. Results will be presented to show the changes in VWC associated with plant development through the vegetative and reproductive stages as well as diurnal variations associated with water availability in the root zone and variations in evaporative demand. In addition, fresh biomass, dry biomass and vegetation water content will be related to brightness temperature observations from (1) the SMAP and SMOS satellite missions, (2) the PALS instrument flown during the SMAPVEX16 IOPs in Iowa (3) the tower-based radiometers located at the soybean and corn fields.

  10. Electrokinetics dependence on water-content in sand

    NASA Astrophysics Data System (ADS)

    Allègre, V.; Lehmann, F.; Jouniaux, L.; Sailhac, P.; Matthey, P.

    2009-12-01

    The electrokinetic potential results from the coupling between the water flow and the electrical current because of the presence of ions within water. This coupling is well described in fluid-saturated media, however its behavior under unsaturated flow conditions is still discussed. We propose here an experimental approach which can clearly describe streaming potential variations in unsaturated conditions. Several drainage experiments have been performed within a column filled with a clean sand. Streaming potential measurements are combined to capillary pressure and to water content measurements each 10 centimeter along the column. In order to model hydrodymanics during each experiment, we solve Richards equation in an inverse way which allows us to establish the relation between hydraulic conductivity and water content, and retention relation. The electrokinetic coefficient C shows a more complex behavior than it was previously reported and can not be fitted by the existing models. We show that the normalized electrokinetic coefficient increases first when water saturation decreases from 100% to about 80% - 95%, and then decreases as the water saturation decreases, whereas all previous works described a unifrom decrease of the normalized electrokinetic coefficient as water saturation decreases. We delimited two water saturation domains, and deduced two different empirical laws describing the evolution of the electrokinetic coefficient in unsaturated conditions. Finally, electrical potentials data from four different drainage experiments and hydrodynamics were jointly inversed, including electrical conductivity measurements in order to find a robust description of the electrokinetic coefficient behavior in unsaturated conditions.

  11. Assessment of a calibration procedure to estimate soil water content with Sentek Diviner 2000 capacitance probe

    NASA Astrophysics Data System (ADS)

    Rallo, G.; Giordano, G.; Provenzano, G.

    2012-04-01

    In irrigated systems, soil water content is a major factor determining plant growth. Irrigation scheduling criteria are often related to measurements of soil water content or matric potential. Strategies to manage irrigation can be used to optimize irrigation water use or to maximize crop yield and/or quality, in order to increase the net return for the farmer. Of course, whatever criterion is adopted to schedule irrigation and in particular when crop water stress conditions are considered, the accurate monitoring of the water content in the soil profile, could allow to verify the exact irrigation timing, defined according to the crop response to water stress. Currently many methods are available for determining soil water content on a volume basis (m3m-3) or a tension basis (MPa), as described by Robinson (2008). Recently, distributed fiber optic temperature measurement, has been assessed as a new technique for indirect and precise estimation of soil water contents. Over the past decade Frequency Domain Reflectometry (FDR) probes, allowing to measure the apparent dielectric constant of the soil (K), indirectly related to the volumetric water content (θv), have been improved, due to the good potentiality of capacitance based sensors to in situ measurements of soil water content. However, due to the high variability of K with soil minerals and dry plants tissues, it necessary to proceed to a specific calibration of the sensor for each soil (Baumhardt et al., 2000), even to take into account the effect of soil temperature, bulk density and water salinity (Al Ain et al., 2009). . According to Paltineanu and Starr (1997), the precision of the calibration equation, obtained with in situ measurements, mainly depends on the errors related to the sampling of the soil volume investigated by the sensor, that must be done accurately. For swelling/shrinking soils, the changes of soil bulk volume with water content cause modifications in the geometry of some if not all the

  12. Review of Suction Water Content Relationship of Bentonite-Sand Mixtures Considering Temperature Effects

    NASA Astrophysics Data System (ADS)

    Rawat, Abhishek; Zhi Lang, Lin; Baille, Wiebke

    2015-04-01

    Bentonite-sand mixture is one of the candidate sealing/ buffer material for landfills, hazardous and high level radioactive waste repository. The long term satisfactory performance of bentonite sand mixture in terms of load bearing function, sealing function and buffer function is governed by hydro-mechanical response of material under elevated temperature conditions. The suction-water content relationship is one of the key parameter, which govern the thermo-hydro-mechanical behavior of compacted bentonite-sand mixture. This paper presents brief review of suction water content relationships of bentonite-sand mixture considering temperature effects. Numerous parametric models or equations have been developed for representing the soil water characteristics curve i.e. SWCC for isothermal conditions. The most frequently used equations for representing the SWCC are the van Genuchten (1980) and Fredlund and Xing (1994) SWCC equations. Various researchers (Romero et al. 2000; Villar and Lloret, 2004; Tang and Cui, 2005; Agus, 2005; Arifin, 2008) have reported the temperature effect on the water retention behavior of compacted bentonite-sand mixtures. The testing program, results and major conclusions made by above mentioned researchers were discussed in this paper. The changes in hydro-mechanical behavior due to elevated temperature are also discussed based on the suction components of soil which are influenced by temperature. As a general conclusion, total suction of the bentonite-sand mixtures is a function of mixture water content and mixture bentonite content or collectively a function of bentonite water content both at room temperature and at elevated temperature. At a constant temperature, different techniques for measuring suction results in different values of suction depending on accuracy of the sensor and calibration technique used as founded earlier by Agus (2005). The change in total suction due to change in temperature lower than 100 degree C is reversible

  13. Water content and water repellency in a field. Implications for irrigation strategies

    NASA Astrophysics Data System (ADS)

    Thwaites, L. A.; de Rooij, G. H.; Salzman, S.; Allinson, G.; Stagnitti, F.; Carr, R.; Versace, V.; Struck, S.; March, T.

    2010-05-01

    The degree of water repellency of soil material depends on its water content. Irrigated soils preferably should be kept sufficiently wet to render the soil wettable, in order to prevent irrigation water bypassing the root zone. But if this leads to overirrigation, the risk of groundwater pollution increases. We applied three irrigation regimes to individual trees in a Eucalyptus plantation on water-repellent soil. The resulting unimodal distribution of shallow water contents produced a bimodal distribution in the degree of water repellency: at any location, the soil would most likely be either wettable, or strongly water-repellent. We developed a procedure to estimate from both distributions the area of wettable soil based on a population of locally determined water contents.

  14. SAPWOOD WATER CONTENT IS INSENSITIVE TO CHANGES IN SOIL MOISTURE

    EPA Science Inventory

    Changes in sapwood water content of large Douglas fir (Pseudotsuga menziesii) trees were measured throughout the year at two sites: a low elevation (600-m) site where precipitation occurs primarily as rain, and a high elevation (1200-m) site that receives significant snowfall. B...

  15. Optical sensing of vegetation water content: A synthesis study

    USDA-ARS?s Scientific Manuscript database

    Vegetation Water Content (VWC) plays an important role in parameterizing the vegetation influence on microwave soil moisture retrieval. During the past decade, researchers have developed relationships between VWC and vegetation indices available from satellite optical sensors in order to create larg...

  16. A review on temporal stability of soil water contents

    USDA-ARS?s Scientific Manuscript database

    Temporal stability of soil water content (TS SWC) has been observed across a wide range of soil types, landscapes, climates and scales. A better understanding of TS SWC controls and their interactions needs to be developed. The objective of this work is to develop a comprehensive inventory of publis...

  17. Effective Calibration of Low-Cost Soil Water Content Sensors

    PubMed Central

    Bogena, Heye Reemt; Huisman, Johan Alexander; Schilling, Bernd; Weuthen, Ansgar; Vereecken, Harry

    2017-01-01

    Soil water content is a key variable for understanding and modelling ecohydrological processes. Low-cost electromagnetic sensors are increasingly being used to characterize the spatio-temporal dynamics of soil water content, despite the reduced accuracy of such sensors as compared to reference electromagnetic soil water content sensing methods such as time domain reflectometry. Here, we present an effective calibration method to improve the measurement accuracy of low-cost soil water content sensors taking the recently developed SMT100 sensor (Truebner GmbH, Neustadt, Germany) as an example. We calibrated the sensor output of more than 700 SMT100 sensors to permittivity using a standard procedure based on five reference media with a known apparent dielectric permittivity (1 < Ka < 34.8). Our results showed that a sensor-specific calibration improved the accuracy of the calibration compared to single “universal” calibration. The associated additional effort in calibrating each sensor individually is relaxed by a dedicated calibration setup that enables the calibration of large numbers of sensors in limited time while minimizing errors in the calibration process. PMID:28117731

  18. SAPWOOD WATER CONTENT IS INSENSITIVE TO CHANGES IN SOIL MOISTURE

    EPA Science Inventory

    Changes in sapwood water content of large Douglas fir (Pseudotsuga menziesii) trees were measured throughout the year at two sites: a low elevation (600-m) site where precipitation occurs primarily as rain, and a high elevation (1200-m) site that receives significant snowfall. B...

  19. Measurement of soil water content with dielectric dispersion frequency

    USDA-ARS?s Scientific Manuscript database

    Frequency domain reflectometry (FDR) is an inexpensive and attractive methodology for repeated measurements of soil water content (SWC). Although there are some known measurement limitations for dry soil and sand, a fixed-frequency method is commonly employed using commercially available FDR probes....

  20. WATER CONTENT-TEMPERATURE INTERACTIONS REGULATE SEED AGING

    USDA-ARS?s Scientific Manuscript database

    Water content and temperature are important factors that influence the duration of seed survival in storage. The interacting effect of these two factors and the consequences on seed longevity is rarely recognized. An experiment to quantify the interaction was begun in 1994, using lettuce (Lactuca s...

  1. Mapping soil water content on golf course greens with GPR

    USDA-ARS?s Scientific Manuscript database

    Ground-penetrating radar (GPR) can be an effective and efficient method for high-resolution mapping of volumetric water content in the sand layer directly beneath the ground surface at a golf course green. This information could potentially be very useful to golf course superintendents for determi...

  2. Observed reflectivities and liquid water content for marine stratocumulus

    NASA Technical Reports Server (NTRS)

    Coakley, J. A., Jr.; Snider, J. B.

    1989-01-01

    Simultaneous observations of cloud liquid water content and cloud reflectivity are used to verify their parametric relationship in a manner consistent with simple parameterizations often used in general-circulation climate models. The column amount of cloud liquid water was measured with a microwave radiometer on San Nicolas Island as described by Hogg et al., (1983). Cloud reflectivity was obtained through spatial coherence analysis of AVHRR imagery data as per Coakley and Baldwin (1984) and Coakley and Beckner (1988). The dependence of the observed reflectivity on the observed liquid water is discussed, and this empirical relationship is compared with the parameterization proposed by Stephens (1978).

  3. [FEATURES OF THE CONTENT OF DRINKING WATER IN THE CITY OF MAGADAN AND POPULATION HEALTH].

    PubMed

    Lugovaya, E A; Stepanova, E M

    2016-01-01

    By methods of atom-emission and mass spectrometry with inductively bonded argon plasma there was determined the content of 25 macro- and trace elements in tap cold drinking water used by the residents of the city of Magadan for food purposes and in hair samples of 30 young male Europeans aged of 17-23 years, who are the residents, of the city of Magadan. According to our data the content of 25 elements in drinking water conforms to standards, but that content of such essential elements as Co, Cr Cu, I, Mn, Na, Se, Zn is shown to be lower than referential indices. After boiling the water the concentration of trace elements is changed. The content of Cd, Cu, K, P Pb, Zn, Ni becomes lower significantly. In healthy young men aged of 17-23 years, from the number of natives Europeoids, residents of the North there was detected deficit of Co and I (86% and 62%, respectively), lower concentrations of Ca, Mg, Se, Zn (76%, 69%, 24%, 24%, respectively). The constant use by residents of the city of Magadan of ultrafresh brackish drinking water in food aims may be the one of the main reasons of the imbalance of macro- and micronutrients in the body, characterized by features of the so-called "northern" type with a marked deficiency of basic essential elements.

  4. The water content of recurring slope lineae on Mars

    USGS Publications Warehouse

    Edwards, Christopher S.; Piqueux, Sylvain

    2016-01-01

    Observations of recurring slope lineae (RSL) from the High-Resolution Imaging Science Experiment have been interpreted as present-day, seasonally variable liquid water flows; however, orbital spectroscopy has not confirmed the presence of liquid H2O, only hydrated salts. Thermal Emission Imaging System (THEMIS) temperature data and a numerical heat transfer model definitively constrain the amount of water associated with RSL. Surface temperature differences between RSL-bearing and dry RSL-free terrains are consistent with no water associated with RSL and, based on measurement uncertainties, limit the water content of RSL to at most 0.5–3 wt %. In addition, distinct high thermal inertia regolith signatures expected with crust-forming evaporitic salt deposits from cyclical briny water flows are not observed, indicating low water salinity (if any) and/or low enough volumes to prevent their formation. Alternatively, observed salts may be preexisting in soils at low abundances (i.e., near or below detection limits) and largely immobile. These RSL-rich surfaces experience ~100 K diurnal temperature oscillations, possible freeze/thaw cycles and/or complete evaporation on time scales that challenge their habitability potential. The unique surface temperature measurements provided by THEMIS are consistent with a dry RSL hypothesis or at least significantly limit the water content of Martian RSL.

  5. The water content of recurring slope lineae on Mars

    NASA Astrophysics Data System (ADS)

    Edwards, Christopher S.; Piqueux, Sylvain

    2016-09-01

    Observations of recurring slope lineae (RSL) from the High-Resolution Imaging Science Experiment have been interpreted as present-day, seasonally variable liquid water flows; however, orbital spectroscopy has not confirmed the presence of liquid H2O, only hydrated salts. Thermal Emission Imaging System (THEMIS) temperature data and a numerical heat transfer model definitively constrain the amount of water associated with RSL. Surface temperature differences between RSL-bearing and dry RSL-free terrains are consistent with no water associated with RSL and, based on measurement uncertainties, limit the water content of RSL to at most 0.5-3 wt %. In addition, distinct high thermal inertia regolith signatures expected with crust-forming evaporitic salt deposits from cyclical briny water flows are not observed, indicating low water salinity (if any) and/or low enough volumes to prevent their formation. Alternatively, observed salts may be preexisting in soils at low abundances (i.e., near or below detection limits) and largely immobile. These RSL-rich surfaces experience ~100 K diurnal temperature oscillations, possible freeze/thaw cycles and/or complete evaporation on time scales that challenge their habitability potential. The unique surface temperature measurements provided by THEMIS are consistent with a dry RSL hypothesis or at least significantly limit the water content of Martian RSL.

  6. Total Water Content Measurements with an Isokinetic Sampling Probe

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew L.; Miller, Dean R.; Bidwell, Colin S.

    2010-01-01

    The NASA Glenn Research Center has developed a Total Water Content (TWC) Isokinetic Sampling Probe. Since it is not sensitive to cloud water particle phase nor size, it is particularly attractive to support super-cooled large droplet and high ice water content aircraft icing studies. The instrument is comprised of the Sampling Probe, Sample Flow Control, and Water Vapor Measurement subsystems. Analysis and testing have been conducted on the subsystems to ensure their proper function and accuracy. End-to-end bench testing has also been conducted to ensure the reliability of the entire instrument system. A Stokes Number based collection efficiency correction was developed to correct for probe thickness effects. The authors further discuss the need to ensure that no condensation occurs within the instrument plumbing. Instrument measurements compared to facility calibrations from testing in the NASA Glenn Icing Research Tunnel are presented and discussed. There appears to be liquid water content and droplet size effects in the differences between the two measurement techniques.

  7. Application of the Bahe's pseudolattice-theory to water-1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)) mixtures at 298.15K Part I. Autoprotolysis constants.

    PubMed

    Bou Malham, I; Letellier, P; Turmine, M

    2007-04-15

    The autoprotolysis constants (K(s)) of water - 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)) mixtures were determined at 298K over the composition range of 0 to 77.43vol.% bmimBF(4) using potentiometric method with a glass electrode. A slight increase in the autoprotolysis constant was observed when the salt was added to the water. The value of the ionic product of the medium then decreases as the bmimBF(4) content increases from about 20vol.%. The acid-base properties of these media were perfectly described by Bahe's approaches that were completed by Varela et al. concerning structured electrolyte solutions with large short-range interactions.

  8. Microdrops on atomic force microscope cantilevers: evaporation of water and spring constant calibration.

    PubMed

    Bonaccurso, Elmar; Butt, Hans-Jürgen

    2005-01-13

    The evaporation of water drops with radii approximately 20 microm was investigated experimentally by depositing them onto atomic force microscope (AFM) cantilevers and measuring the deflection versus time. Because of the surface tension of the liquid, the Laplace pressure inside the drop, and the change of interfacial stress at the solid-liquid interface, the cantilever is deflected by typically a few hundred nanometers. The experimental results are in accordance with an analytic theory developed. The evaporation process could be monitored with high accuracy even at the last stage of evaporation because (1) cantilever deflections can be measured with nanometer resolution and (2) the time resolution, given by the inverse of the resonance frequency of the cantilever of approximately 0.3 ms, is much faster than the typical evaporation time of 1 s. Experimental results indicate that evaporation of the last thin layer of water is significantly slower than the rest of the drop, which can be due to surface forces. This drop-on-cantilever system can also be used to analyze the drop impact dynamics on a surface and to determine the spring constant of cantilevers.

  9. [Estimating canopy water content in wheat based on new vegetation water index].

    PubMed

    Cheng, Xiao-juan; Yang, Gui-jun; Xu, Xin-gang; Chen, Tian-en; Li, Zhen-hai; Feng, Hai-kuan; Wang, Dong

    2014-12-01

    Moisture content is an important indicator for crop water stress condition, timely and effective monitoring crop water content is of great significance for evaluate crop water deficit balance and guide agriculture irrigation. In order to improve the saturated problems of different forms of typical NDWI (Normalized Different Water Index), we tried to introduce EVI (Enhanced Vegetation Index) to build new vegetation water indices (NDWI#) to estimate crop water content. Firstly, PROSAIL model was used to study the saturation sensitivity of NDWI, and NDWI# to canopy water content and LAI (Leaf Area Index). Then, the estimated model and verified model were estimated using the spectral data and moisture data in the field. The result showed that the new indices have significant relationships with canopy water content. In particular, by implementing modified standardized for NDWI1450, NDWI1940, NDWI2500. The result indicated that newly developed indices with visible-infrared and shortwave infrared spectral feature may have greater advantage for estimation winter canopy water content.

  10. Assessment of change in soil water content properties irrigated with industrial sugar beet wastewater.

    PubMed

    Tabatabaei, Sayyed Hassan; Najafi, Payam; Amini, Hussein

    2007-05-15

    In this research the effect of industrial sugar beet wastewater has been assessed on the soil water content properties in summer 2005. The evaluated parameters were the soil water content points such as Saturation Percent (SP), Field Capacity (FC), Permanent Wilting Point (PWP), gravitational water and Total Available Water (TAW). The pilot design was fully randomized with three replications and three treatments. The three treatments were: 1-normal water, 2-industrial sugar beet wastewater (50%) and normal water (50%) and 3-sugar beet wastewater (100%). The experiments have been carried out in the field, in 21 columns with the diameter 110 mm and the height of 400 mm. The soil was irrigated using surface irrigation method for 12 events with a constant volume and period. Based on the result, the SP, FC and PWP initial value were 46.5, 35 and 15%, respectively for all the treatments. At the end of the period, the values changed to 47, 36.6 and 17.5% for T2. They are also increased significantly to 48.5, 37 and 18.7% for T3 at the end of the period. The increasing of soil Organic Matter (OM) during the period is expected to be the main factor for this change. The result shows that although the FC and PWP parameters are increased during the period but TAW decreased significantly from the 20 to 18.5%. The other effects of wastewater on soil and leached water quality should be evaluated too.

  11. Measurement of water content in high water-cut oil-wells based on rayleigh scattering

    NASA Astrophysics Data System (ADS)

    MA, Weili; WANG, Yansong; WANG, Jianguo; WANG, Yiming; WANG, Jia; WU, Shitong; WANG, Diandong; GUO, Wenyong; LI, Yun; ZHANG, Baohui; LI, Zhenlong; LIU, Wensheng; XU, Guanghui; XU, Rui

    2017-04-01

    According to the lack of traditional method measuring high water-cut production level effectively, this paper discusses the measurement of high water content by Rayleigh scattering. When launching high-frequency electromagnetic waves downward along the axial, the diameter of the oil-in-water emulsion can range from millimeter to centimeter in an oil-water two-phase case. Because the Electromagnetic Wave can be scattered by oil droplets and is related to their quantities and size, we can measure the water content using suitable electromagnetic wave with the right wavelength. Then, the measuring accuracy of Water Content in High Water-cut Oil-wells can be improved and the confluent-liquid umbrella can also be canceled.

  12. Water contents of clinopyroxenes from sub-arc mantle peridotites

    USGS Publications Warehouse

    Turner, Michael; Turner, Simon; Blatter, Dawnika; Maury, Rene; Perfit, Michael; Yogodzinski, Gene

    2017-01-01

    One poorly constrained reservoir of the Earth's water budget is that of clinopyroxene in metasomatised, mantle peridotites. This study presents reconnaissance Sensitive High-Resolution, Ion Microprobe–Stable Isotope (SHRIMP–SI) determinations of the H2O contents of (dominantly) clinopyroxenes in rare mantle xenoliths from four different subduction zones, i.e. Mexico, Kamchatka, Philippines, and New Britain (Tabar-Feni island chain) as well as one intra-plate setting (western Victoria). All of the sub-arc xenoliths have been metasomatised and carry strong arc trace element signatures. Average measured H2O contents of the pyroxenes range from 70 ppm to 510 ppm whereas calculated bulk H2O contents range from 88 ppm to 3 737 ppm if the variable presence of amphibole is taken into account. In contrast, the intra-plate, continental mantle xenolith from western Victoria has higher water contents (3 447 ppm) but was metasomatised by alkali and/or carbonatitic melts and does not carry a subduction-related signature. Material similar to the sub-arc peridotites can either be accreted to the base of the lithosphere or potentially be transported by convection deeper into the mantle where it will lose water due to amphibole breakdown.

  13. Modeling water content effects in polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Springer, T. E.; Zawodzinski, T. A.; Gottesfeld, S.

    Water content and transport is the key factor in the one-dimensional, steady-state model of a complete polymer electrolyte fuel cell (PEFC) described here. Water diffusion coefficients, electroosmotic drag coefficients, water sorption isotherms, and membrane conductivities, all measured in our laboratory as functions of membrane water content, were used in the model. The model predicts a net-water-per-proton flux ratio of 0.2 H2O/H(sup +) under typical operating conditions, which is much less than the measured electroosmotic drag coefficient for a fully hydrated membrane. It also predicts an increase in membrane resistance with increased current density and demonstrates the great advantage of thinner membranes in alleviating this resistance problem. Both of these predictions were verified experimentally under certain conditions. We also describe the sensitivity of the water concentration profile and associated observables to variations in the values of some of the transport parameters in anticipation of applying the model to fuel cells employing other membranes.

  14. Large Martian regolith water content implied by rampart crater population

    NASA Astrophysics Data System (ADS)

    Stewart, S. T.; Ahrens, T. J.; O'Keefe, J. D.

    2001-12-01

    We estimate the global regolith water content using a new model for rampart crater formation (Stewart et al.~LPSC 2001). The Martian surface has a high fraction (probably significantly >20%) of craters with so-called fluidized ejecta blankets, characterized by the appearance of ground-hugging flow terminating in one or more continuous distal ramparts. While rampart craters have long held the promise of revealing information about the water content of the Martian regolith, the lack of a comprehensive physical model for the formation of fluidized ejecta blankets has hindered quantitative studies. We have developed a model for rampart crater formation based on ice shock data obtained at Martian temperatures and numerical simulations of impacts onto ice-rock mixtures under Martian conditions. We find that significant quantities of liquid water may be produced by an impact event and that the excavation process is modified by the presence of interstitial ice. As a result, single or multiple rampart ejecta blankets do not require the presence of pre-existing water in the liquid phase. A few to several volume percent of shock-produced liquid water may be incorporated into the continuous ejecta blanket for average impact conditions and reasonable regolith pore space assumptions, e.g. 15~vol% ice-filled near-surface pores. For a given diameter rampart crater, we calculate the associated minimum regolith ice content. Using the Viking-based rampart crater database by Barlow and Bradley (1990), the observed rampart crater population ( ~20% of all craters) implies a minimum regolith ice content of order 0.1~m global layer equivalent. The Mars Orbiter Laser Altimeter (MOLA) data suggest that a much larger fraction of craters, especially in the northern plains, may have rampart ejecta features. To derive the implied global regolith ice content, we correct for the impact flux rate over the past ~3~Ga using a number density for 1-10~km diameter craters, the peak rampart crater size

  15. Impact of water content and decomposition stage on the soil water repellency of peat soils

    NASA Astrophysics Data System (ADS)

    Dettmann, Ullrich; Sokolowsky, Liv; Piayda, Arndt; Tiemeyer, Bärbel; Bachmann, Jörg

    2017-04-01

    Soil water repellency is widely reported for all kinds of soils and mainly caused by hydrophobic organic compounds. It has a substantial influence on soil hydraulic processes such as water infiltration, preferential flow paths and evaporation and therefore on hydrological processes in general. The severity of soil water repellency strongly depends on the soil water content and the amount of soil organic carbon. Although peat soils are characterized by high soil organic carbon contents, studies about peat soils are rare and mostly available for horticultural substrates. Here, we present soil water repellency measurements for peat soils with varying porosities, bulk densities and stages of decomposition. The peat soils were sampled at two different sites in a bog complex. The sites have been drained for 1 and 100 years. Samples were taken from each soil layer and, additionally, in a vertical resolution of 0.03 m. To determine the soil water contents at which the peat becomes water repellent, we applied the commonly used water drop penetration time test on progressively dewatered samples. In order to identify the influence of the decomposition stage as determined by the depth within the soil profile and duration of drainage, the potential soil water repellency was measured at air-dried sieved samples by the sessile drop method. First results show that the soil water repellency of peat soils is strongly dependent on the soil water content. For air-dried peat samples, the influence of different decomposition stages of the bog peat is negligible. All air-dried samples are extremely water repellent with contact angles > 130°. However, comparing the results with the soil organic matter content shows a slightly tendency of increasing soil water repellency with increasing soil organic matter contents.

  16. Constants and thermodynamics of the acid-base equilibria of triglycine in water-ethanol solutions containing sodium perchlorate at 298 K

    NASA Astrophysics Data System (ADS)

    Pham Tkhi, L.; Usacheva, T. R.; Tukumova, N. V.; Koryshev, N. E.; Khrenova, T. M.; Sharnin, V. A.

    2016-02-01

    The acid-base equilibrium constants for glycyl-glycyl-glycine (triglycine) in water-ethanol solvents containing 0.0, 0.1, 0.3, and 0.5 mole fractions of ethanol are determined by potentiometric titration at 298.15 K and an ionic strength of 0.1, maintained with sodium perchlorate. It is established that an increase in the ethanol content in the solvent reduces the dissociation constant of the carboxyl group of triglycine (increases p K 1) and increases the dissociation constant of the amino group of triglycine (decreases p K 2). It is noted that the weakening of the acidic properties of a triglycinium ion upon an increase of the ethanol content in the solvent is due to the attenuation of the solvation shell of the zwitterionic form of triglycine, and to the increased solvation of triglycinium ions. It is concluded that the acid strength of triglycine increases along with a rise in the EtOH content in the solvent, due to the desolvation of the tripeptide zwitterion and the enhanced solvation of protons.

  17. Comparison of the Mineral Content of Tap Water and Bottled Waters

    PubMed Central

    Azoulay, Arik; Garzon, Philippe; Eisenberg, Mark J

    2001-01-01

    OBJECTIVES Because of growing concern that constituents of drinking water may have adverse health effects, consumption of tap water in North America has decreased and consumption of bottled water has increased. Our objectives were to 1) determine whether North American tap water contains clinically important levels of calcium (Ca2+), magnesium (Mg2+), and sodium (Na+) and 2) determine whether differences in mineral content of tap water and commercially available bottled waters are clinically important. DESIGN We obtained mineral analysis reports from municipal water authorities of 21 major North American cities. Mineral content of tap water was compared with published data regarding commercially available bottled waters and with dietary reference intakes (DRIs). MEASUREMENTS AND MAIN RESULTS Mineral levels varied among tap water sources in North America and among bottled waters. European bottled waters generally contained higher mineral levels than North American tap water sources and North American bottled waters. For half of the tap water sources we examined, adults may fulfill between 8% and 16% of their Ca2+ DRI and between 6% and 31% of their Mg2+ DRI by drinking 2 liters per day. One liter of most moderate mineralization European bottled waters contained between 20% and 58% of the Ca2+ DRI and between 16% and 41% of the Mg2+ DRI in adults. High mineralization bottled waters often contained up to half of the maximum recommended daily intake of Na+. CONCLUSION Drinking water sources available to North Americans may contain high levels of Ca2+, Mg2+, and Na+ and may provide clinically important portions of the recommended dietary intake of these minerals. Physicians should encourage patients to check the mineral content of their drinking water, whether tap or bottled, and choose water most appropriate for their needs. PMID:11318912

  18. Monitoring of soil water content and quality inside and outside the water curtain cultivation facility

    NASA Astrophysics Data System (ADS)

    Ha, K.; Kim, Y.

    2014-12-01

    Water curtain cultivation system is an energy saving technique for winter season by splashing groundwater on the inner roof of green house. Artificial groundwater recharge application to the water curtain cultivation facilities was adopted and tested to use groundwater sustainably in a rural region of Korea. The groundwater level in the test site shows natural trend corresponding rainfall pattern except during mid-November to early April when groundwater levels decline sharply due to groundwater abstraction for water curtain cultivation. Groundwater levels are also affected by surface water such as stream, small dams in the stream and agricultural ditches. Infiltration data were collected from lysimeter installation and monitoring inside and outside water cultivation facility and compared with each other. The infiltration data were well correlated with rainfall outside the facility, but the data in the facility showed very different from the other. The missing infiltration data were attributed to groundwater level rise and level sensor location below water table. Soil water contents in the unsaturated zone indicated rainfall infiltration propagation at depth and with time outside the facility. According to rainfall amount and water condition at the initial stage of a rainfall event, the variation of soil water content was shown differently. Soil water contents and electrical conductivities were closely correlated with each other, and they reflected rainfall infiltration through the soil and water quality changes. The monitoring results are useful to reveal the hydrological processes from the infiltration to groundwater recharge, and water management planning in the water cultivation areas.

  19. Influence of the initial soil water content on Beerkan water infiltration experiments

    NASA Astrophysics Data System (ADS)

    Lassabatere, L.; Loizeau, S.; Angulo-Jaramillo, R.; Winiarski, T.; Rossier, Y.; Delolme, C.; Gaudet, J. P.

    2012-04-01

    Understanding and modeling of water flow in the vadose zone are important with regards water management and infiltration devices design. Water infiltration process clearly depends on initial soil water content, in particular for sandy soils with high organic matter content. This study investigates the influence of initial water content on water infiltration in a hydrophobic sandy soil and on the related derivation of hydraulic parameters using the BEST algorithm (Lassabatere et al., 2006). The studied sandy soil has a high total organic content decreasing from 3.5% (w/w) at the surface to 0.5% (w/w) below 1cm depth. The highest TOC at surface was due to the presence of a dense biofilm and resulted in a high surface hydrophobicity under dry conditions (low initial water contents). The water infiltration experiments consisted in infiltrating known volumes of water through a simple ring at null pressure head (Beerkan method). The infiltrations were performed during three successive days after a dry period with a storm event between the first and the second day (5 mm) and another between the second and the third day (35 mm). These events resulted in an increase in initial water contents, from less than 5% for the first day to around 10% for the last day. Experiments were performed for appropriate conditions for Beerkan experiments: initial water contents below 1/4 of the saturated water content and uniform water profile resulting from water redistribution after each rainfall event. The analysis of the infiltration data clearly highlights the strong effect of hydrophobicity. For the driest initial conditions (first day), infiltration rates increased with time, whereas they decreased with time for wetter conditions. Such a decrease agreed with the principles of water infiltration without hydrophobicity. In addition, total cumulative infiltrations were far higher for the wettest conditions. Regarding hydraulic characterization, only the data obtained during the last

  20. Water content test for EOR crude simulates desalter

    SciTech Connect

    Duke, R.B. )

    1991-02-25

    Crude oil produced from enhanced oil recovery (EOR) projects employing micellar/polymer flooding can require an alternative test method for water content to the ASTM centrifuge test, or grindout procedure. The reason is that centrifuging cannot break the surfactant-stabilized emulsion. As an alternative, Marathon Oil Co. has developed a simulated desalter test (SDT) and necessary apparatus for the accurate evaluation of the quality of crude oil from such projects. Oil quality parameters such as basic sediment and water values are used almost universally for determining the acceptability of crude oil into pipeline or refinery systems.

  1. Product distributions and rate constants for ion-molecule reactions in water, hydrogen sulfide, ammonia, and methane

    NASA Technical Reports Server (NTRS)

    Huntress, W. T., Jr.; Pinizzotto, R. F., Jr.

    1973-01-01

    The thermal energy, bimolecular ion-molecule reactions occurring in gaseous water, hydrogen sulfide, ammonia, and methane have been identified and their rate constants determined using ion cyclotron resonance methods. Absolute rate constants were determined for the disappearance of the primary ions by using the trapped ion method, and product distributions were determined for these reactions by using the cyclotron ejection method. Previous measurements are reviewed and compared with the results using the present methods. The relative rate constants for hydrogen-atom abstraction, proton transfer, and charge transfer are also determined for reactions of the parent ions.

  2. Product distributions and rate constants for ion-molecule reactions in water, hydrogen sulfide, ammonia, and methane

    NASA Technical Reports Server (NTRS)

    Huntress, W. T., Jr.; Pinizzotto, R. F., Jr.

    1973-01-01

    The thermal energy, bimolecular ion-molecule reactions occurring in gaseous water, hydrogen sulfide, ammonia, and methane have been identified and their rate constants determined using ion cyclotron resonance methods. Absolute rate constants were determined for the disappearance of the primary ions by using the trapped ion method, and product distributions were determined for these reactions by using the cyclotron ejection method. Previous measurements are reviewed and compared with the results using the present methods. The relative rate constants for hydrogen-atom abstraction, proton transfer, and charge transfer are also determined for reactions of the parent ions.

  3. Interferometric tomography of fuel cells for monitoring membrane water content.

    PubMed

    Waller, Laura; Kim, Jungik; Shao-Horn, Yang; Barbastathis, George

    2009-08-17

    We have developed a system that uses two 1D interferometric phase projections for reconstruction of 2D water content changes over time in situ in a proton exchange membrane (PEM) fuel cell system. By modifying the filtered backprojection tomographic algorithm, we are able to incorporate a priori information about the object distribution into a fast reconstruction algorithm which is suitable for real-time monitoring.

  4. Soil water content assessment: seasonal effects on the triangle method

    NASA Astrophysics Data System (ADS)

    Maltese, A.; Capodici, F.; Ciraolo, G.; La Loggia, G.; Cammalleri, C.

    2016-10-01

    Among indirect estimations of the soil water content in the upper layer, the "triangle method" is based on the relationship between the optical and thermal features sensed via Earth Observation. These features are controlled by water content at surface and within root zone, but also by meteorological forcing including air temperature and humidity, and solar radiation. Night and day-time MODIS composite land-surface temperature (LST) allowed applying the thermal admittance version of the method; by taking into account the temporal admittance of the soil, this version was previously found achieving high accuracy in estimate the soil water content at high spatial resolution within a short time period (a single irrigation season). In this study, the method has been applied on a long time series to analyse the seasonal influence of the meteorological forcing on the triangle method index (or temperature vegetation index, TVX). The Imera Meridionale hydrological basin (≍ 2000 km2, Sicily) has been chosen to test the method over a decade time series, since its climate varies during the year from arid to temperate. The climate is arid for ≍3-7 months (from April-May to August- October) depending on altitude. The temporal analysis reveals that NDVI and LST pairs moves circularly within the optical and thermal diachronic feature space. Concordantly, the boundaries of the triangle move during the seasons. Results suggest that the contribution of soil water content fluctuations need to be isolated from other environmental stress factors, or at least, the conceptual meaning of TVX have to be better interpreted.

  5. Effect of water and temperature stress on the content of active constituents of Hypericum brasiliense Choisy.

    PubMed

    Nacif de Abreu, Ilka; Mazzafera, Paulo

    2005-03-01

    Hypericum brasiliense is a medicinal herb containing several compounds with important pharmacological activity. In this study, we investigated the effects of water stress (waterlogging and drought) and temperature (low and high, constant and alternate) on the content of betulinic acid and phenolic compounds (quercetin, rutin, 1,5-dihydroxyxanthone, isouliginosin B) in this species. In general, the water stress increased the levels of all of the compounds analyzed, particularly some of the phenolic compounds. On the other hand, the responses to alternating temperatures varied according to the compound. The results for plants kept in growth chambers indicated that low light intensity might have influenced the levels of the compounds. There was also a reallocation of carbon, with water-stressed plants showing a reduction in growth while the levels of the compounds increased. In the temperature treatments, such an increase was evident only for the phenolic compounds.

  6. Plant Response to Differential Soil Water Content and Salinity

    NASA Astrophysics Data System (ADS)

    Moradi, A. B.; Dara, A.; Kamai, T.; Ngo, A.; Walker, R.; Hopmans, J. W.

    2011-12-01

    Root-zone soil water content is extremely dynamic, governed by complex and coupled processes such as root uptake, irrigation, evaporation, and leaching. Root uptake of water and nutrients is influenced by these conditions and the processes involved. Plant roots are living and functioning in a dynamic environment that is subjected to extreme changes over relatively short time and small distances. In order to better manage our agricultural resources and cope with increasing constraints of water limitation, environmental concerns and climate change, it is vital to understand plants responses to these changes in their environment. We grew chick pea (Cicer arietinum) plants, in boxes of 30 x 25 x 1 cm dimensions filled with fine sand. Layers of coarse sand (1.5 cm thick) were embedded in the fine-sand media to divide the root growth environment into sections that were hydraulically disconnected from each other. This way, each section could be independently treated with differential levels of water and salinity. The root growth and distribution in the soil was monitored on daily bases using neutron radiography. Daily water uptake was measured by weighing the containers. Changes of soil water content in each section of the containers were calculated from the neutron radiographs. Plants that part of their root system was stressed with drought or salinity showed no change in their daily water uptake rate. The roots in the stressed sections stayed turgid during the stress period and looked healthy in the neutron images. However the uptake rate was severely affected when the soil in the non-stressed section started to dry. The plants were then fully irrigated with water and the water uptake rate recovered to its initial rate shortly after irrigation. The neutron radiographs clearly illustrated the shrinkage and recovery of the roots under stress and the subsequent relief. This cycle was repeated a few times and the same trend could be reproduced. Our results show that plants

  7. Determination of Henry's law constants of organochlorine pesticides in deionized and saline water as a function of temperature

    NASA Astrophysics Data System (ADS)

    Cetin, Banu; Ozer, Serdar; Sofuoglu, Aysun; Odabasi, Mustafa

    The Henry's law constant ( H) is an important parameter that is required to estimate the air-water exchange of semi-volatile organic compounds. Henry's law constants for 17 banned/restricted/currently used organochlorine pesticides (OCPs) were experimentally determined using a gas-stripping technique in deionized and saline water (3%) over a temperature range of 5-35 °C. H values (at 25 °C) ranged between 0.066±0.037 Pa m 3 mol -1 (endosulfan II) and 62.0±24.2 Pa m 3 mol -1 (heptachlor) in deionized water while the range in saline water was 0.28±0.03 Pa m 3 mol -1 ( γ-HCH) and 135.2±31.3 Pa m 3 mol -1 (heptachlor). The increase in dimensionless Henry's law constants ( H') for OCPs over the studied temperature range was between 3 ( γ-HCH)-19 times (chlorpyrifos) and 3 (endosulfan II)-80 times ( trans-nonachlor) in deionized and saline water, respectively. The calculated enthalpies of phase change (Δ HH) were within the ranges previously reported for OCPs and other organic compounds (23.8-100.2 kJ mol -1). The salting-out constant, ks, ranged between 0.04 ( γ-HCH) and 1.80 L mol -1 (endosulfan II) indicating the importance of assessing the H values of OCPs in saline water to accurately determine their partitioning and fate in seawater.

  8. Radiometric estimation of water vapor content over Brazil

    NASA Astrophysics Data System (ADS)

    Karmakar, P. K.; Maiti, M.; Sett, S.; Angelis, C. F.; Machado, L. A. T.

    2011-11-01

    A multi-channel microwave radiometre (make: Radiometrics Corporation) is installed at Instituto Nacional de Pesquisas Espaciais-INPE, Brazil (22°S). The radiometric output of two channels of the radiometer in the form of brightness temperature at 23.834 GHz and 30 GHz, initially, were used to find out the ambient water vapor content and the non-precipitable cloud liquid water content. The necessary algorithm was developed for the purpose. The best results were obtained using the hinge frequency 23.834 GHz and 30 GHz pair having an r.m.s. error of only 2.64. The same methodology was then adopted exploiting 23.034 GHz and 30 GHz pair. In that case the r.m.s. error was 3.42. These results were then compared with those obtained over Kolkata (22°N), India, by using 22.234 GHz and 31.4 GHz radiometric data. This work conclusively suggests the use of a frequency should not be at the water vapor resonance line. Instead, while measuring the vapor content for separation of vapor and cloud liquid, one of them should be a few GHz left or right from the resonance line i.e., at 23.834 GHz and the other one should be around 30 GHz.

  9. Monitoring water content in Opalinus Clay within the FE-Experiment: Test application of dielectric water content sensors

    NASA Astrophysics Data System (ADS)

    Sakaki, T.; Vogt, T.; Komatsu, M.; Müller, H. R.

    2013-12-01

    The spatiotemporal variation of water content in the near field rock around repository tunnels for radioactive waste in clay formations is one of the essential quantities to be monitored for safety assessment in many waste disposal programs. Reliable measurements of water content are important not only for the understanding and prediction of coupled hydraulic-mechanic processes that occur during tunnel construction and ventilation phase, but also for the understanding of coupled thermal-hydraulic-mechanical (THM) processes that take place in the host rock during the post closure phase of a repository tunnel for spent fuel and high level radioactive waste (SF/HLW). The host rock of the Swiss disposal concept for SF/HLW is the Opalinus Clay formation (age of approx. 175 Million years). To better understand the THM effects in a full-scale heater-engineered barrier-rock system in Opalinus Clay, a full-scale heater test, namely the Full-Scale Emplacement (FE) experiment, was initiated in 2010 at the Mont Terri underground rock laboratory in north-western Switzerland. The experiment is designed to simulate the THM evolution of a SF/HLW repository tunnel based on the Swiss disposal concept in a realistic manner during the construction, emplacement, backfilling, and post-closure phases. The entire experiment implementation (in a 50 m long gallery with approx. 3 m diameter) as well as the post-closure THM evolution will be monitored using a network of several hundred sensors. The sensors will be distributed in the host rock, the tunnel lining, the engineered barrier, which consists of bentonite pellets and blocks, and on the heaters. The excavation is completed and the tunnel is currently being ventilated. Measuring water content in partially saturated clay-rich high-salinity rock with a deformable grain skeleton is challenging. Therefore, we use the ventilation phase (before backfilling and heating) to examine the applicability of commercial water content sensors and to

  10. Effects of mineral content of bovine drinking water: does iron content affect milk quality?

    PubMed

    Mann, G R; Duncan, S E; Knowlton, K F; Dietrich, A D; O'Keefe, S F

    2013-01-01

    The composition of water given to dairy cattle is often ignored, yet water is a very important nutrient and plays a major role in milk synthesis. The objective of this study was to study effects of elevated levels of iron in bovine drinking water on milk quality. Ferrous lactate treatments corresponding to 0, 2, 5, and 12.5mg/kg drinking water concentrations were delivered through the abomasum at 10 L/d to 4 lactating dairy cows over 4 periods (1 wk infusion/period) in a Latin square design. On d 6 of infusion, milk was collected, processed (homogenized, pasteurized), and analyzed. Mineral content (Fe, Cu, P, Ca) was measured by inductively coupled plasma mass spectrometry. Oxidative stability of whole processed milk was measured by the thiobarbituric acid reactive substances (TBARS) assay for malondialdehyde (MDA) and sensory analysis (triangle test) within 72 h of processing and after 7d of storage (4°C). Significant sensory differences between processed milks from cows receiving iron and the control infusion were observed. No differences in TBARS (1.46±0.04 mg of MDA/kg) or mineral content (0.22±0.01 mg/kg Fe) were observed. A 2-way interaction (iron treatment by cow) for Ca, Cu, and Fe concentrations was seen. While iron added directly to milk causes changes in oxidation of milk, high levels of iron given to cattle have subtle effects that initially may not be obvious.

  11. High water content in primitive continental flood basalts

    PubMed Central

    Xia, Qun-Ke; Bi, Yao; Li, Pei; Tian, Wei; Wei, Xun; Chen, Han-Lin

    2016-01-01

    As the main constituent of large igneous provinces, the generation of continental flood basalts (CFB) that are characterized by huge eruption volume (>105 km3) within short time span (<1–3 Ma) is in principle caused by an abnormally high temperature, extended decompression, a certain amount of mafic source rocks (e.g., pyroxenite), or an elevated H2O content in the mantle source. These four factors are not mutually exclusive. There are growing evidences for high temperature, decompression and mafic source rocks, albeit with hot debate. However, there is currently no convincing evidence of high water content in the source of CFB. We retrieved the initial H2O content of the primitive CFB in the early Permian Tarim large igneous province (NW China), using the H2O content of ten early-formed clinopyroxene (cpx) crystals that recorded the composition of the primitive Tarim basaltic melts and the partition coefficient of H2O between cpx and basaltic melt. The arc-like H2O content (4.82 ± 1.00 wt.%) provides the first clear evidence that H2O plays an important role in the generation of CFB. PMID:27143196

  12. High water content in primitive continental flood basalts

    NASA Astrophysics Data System (ADS)

    Xia, Qun-Ke; Bi, Yao; Li, Pei; Tian, Wei; Wei, Xun; Chen, Han-Lin

    2016-05-01

    As the main constituent of large igneous provinces, the generation of continental flood basalts (CFB) that are characterized by huge eruption volume (>105 km3) within short time span (<1–3 Ma) is in principle caused by an abnormally high temperature, extended decompression, a certain amount of mafic source rocks (e.g., pyroxenite), or an elevated H2O content in the mantle source. These four factors are not mutually exclusive. There are growing evidences for high temperature, decompression and mafic source rocks, albeit with hot debate. However, there is currently no convincing evidence of high water content in the source of CFB. We retrieved the initial H2O content of the primitive CFB in the early Permian Tarim large igneous province (NW China), using the H2O content of ten early-formed clinopyroxene (cpx) crystals that recorded the composition of the primitive Tarim basaltic melts and the partition coefficient of H2O between cpx and basaltic melt. The arc-like H2O content (4.82 ± 1.00 wt.%) provides the first clear evidence that H2O plays an important role in the generation of CFB.

  13. High water content in primitive continental flood basalts.

    PubMed

    Xia, Qun-Ke; Bi, Yao; Li, Pei; Tian, Wei; Wei, Xun; Chen, Han-Lin

    2016-05-04

    As the main constituent of large igneous provinces, the generation of continental flood basalts (CFB) that are characterized by huge eruption volume (>10(5) km(3)) within short time span (<1-3 Ma) is in principle caused by an abnormally high temperature, extended decompression, a certain amount of mafic source rocks (e.g., pyroxenite), or an elevated H2O content in the mantle source. These four factors are not mutually exclusive. There are growing evidences for high temperature, decompression and mafic source rocks, albeit with hot debate. However, there is currently no convincing evidence of high water content in the source of CFB. We retrieved the initial H2O content of the primitive CFB in the early Permian Tarim large igneous province (NW China), using the H2O content of ten early-formed clinopyroxene (cpx) crystals that recorded the composition of the primitive Tarim basaltic melts and the partition coefficient of H2O between cpx and basaltic melt. The arc-like H2O content (4.82 ± 1.00 wt.%) provides the first clear evidence that H2O plays an important role in the generation of CFB.

  14. Laboratory measurements of electrical resistivity versus water content on small soil cores

    NASA Astrophysics Data System (ADS)

    Robain, H.; Camerlynck, C.; Bellier, G.; Tabbagh, A.

    2003-04-01

    The assessment of soil water content variations more and more leans on geophysical methods that are non invasive and that allow a high spatial sampling. Among the different methods, DC electrical imaging is moving forward. DC Electrical resistivity shows indeed strong seasonal variations that principally depend on soil water content variations. Nevertheless, the widely used Archie's empirical law [1], that links resistivity with voids saturation and water conductivity is not well suited to soil materials with high clay content. Furthermore, the shrinking and swelling properties of soil materials have to be considered. Hence, it is relevant to develop new laboratory experiments in order to establish a relation between electrical resistivity and water content taking into account the rheological and granulometrical specificities of soil materials. The experimental device developed in IRD laboratory allows to monitor simultaneously (i) the water content, (ii) the electrical resistivity and (iii) the volume of a small cylindrical soil core (100cm3) put in a temperature controlled incubator (30°C). It provides both the shrinkage curve of the soil core (voids volume versus water content) and the electrical resistivity versus water content curve The modelisation of the shrinkage curve gives for each moisture state the water respectively contained in macro and micro voids [2], and then allows to propose a generalized Archie's like law as following : 1/Rs = 1/Fma.Rma + 1/Fmi.Rmi and Fi = Ai/(Vi^Mi.Si^Ni) with Rs : the soil resistivity. Fma and Fmi : the so called "formation factor" for macro and micro voids, respectively. Rma and Rmi : the resistivity of the water contained in macro and micro voids, respectively. Vi : the volume of macro and micro voids, respectively. Si : the saturation of macro and micro voids, respectively. Ai, Mi and Ni : adjustment coefficients. The variations of Rmi are calculated, assuming that Rma is a constant. Indeed, the rise of ionic

  15. Intra-Abdominal Pressure Correlates with Extracellular Water Content

    PubMed Central

    Dąbrowski, Wojciech; Kotlinska-Hasiec, Edyta; Jaroszynski, Andrzej; Zadora, Przemyslaw; Pilat, Jacek; Rzecki, Ziemowit; Zaluska, Wojciech; Schneditz, Daniel

    2015-01-01

    Background Secondary increase in intra-abdominal pressure (IAP) may result from extra-abdominal pathology, such as massive fluid resuscitation, capillary leak or sepsis. All these conditions increase the extravascular water content. The aim of this study was to analyze the relationship between IAP and body water volume. Material and Methods Adult patients treated for sepsis or septic shock with acute kidney injury (AKI) and patients undergoing elective pharyngolaryngeal or orthopedic surgery were enrolled. IAP was measured in the urinary bladder. Total body water (TBW), extracellular water content (ECW) and volume excess (VE) were measured by whole body bioimpedance. Among critically ill patients, all parameters were analyzed over three consecutive days, and parameters were evaluated perioperatively in surgical patients. Results One hundred twenty patients were studied. Taken together, the correlations between IAP and VE, TBW, and ECW were measured at 408 time points. In all participants, IAP strongly correlated with ECW and VE. In critically ill patients, IAP correlated with ECW and VE. In surgical patients, IAP correlated with ECW and TBW. IAP strongly correlated with ECW and VE in the mixed population. IAP also correlated with VE in critically ill patients. ROC curve analysis showed that ECW and VE might be discriminative parameters of risk for increased IAP. Conclusion IAP strongly correlates with ECW. PMID:25849102

  16. Water Calibration Measurements for Neutron Radiography: Application to Water Content Quantification in Porous Media

    SciTech Connect

    Kang, Misun; Bilheux, Hassina Z; Voisin, Sophie; Cheng, Chu-lin; Perfect, Edmund; Horita, Juske; Warren, Jeffrey

    2013-04-01

    Using neutron radiography, the measurement of water thickness was performed using aluminum (Al) water calibration cells at the High Flux Isotope Reactor (HFIR) Cold-Guide (CG) 1D neutron imaging facility at Oak Ridge National Laboratory, Oak Ridge, TN, USA. Calibration of water thickness is an important step to accurately measure water contents in samples of interest. Neutron attenuation by water does not vary linearly with thickness mainly due to beam hardening and scattering effects. Transmission measurements for known water thicknesses in water calibration cells allow proper correction of the underestimation of water content due to these effects. As anticipated, strong scattering effects were observed for water thicknesses greater than 2 mm when the water calibration cells were positioned close to the face of the detector / scintillator (0 and 2.4 cm away, respectively). The water calibration cells were also positioned 24 cm away from the detector face. These measurements resulted in less scattering and this position (designated as the sample position) was used for the subsequent experimental determination of the neutron attenuation coefficient for water. Neutron radiographic images of moist Flint sand in rectangular and cylindrical containers acquired at the sample position were used to demonstrate the applicability of the water calibration. Cumulative changes in the water volumes within the sand columns during monotonic drainage determined by neutron radiography were compared with those recorded by direct reading from a burette connected to a hanging water column. In general, the neutron radiography data showed very good agreement with those obtained volumetrically using the hanging water-column method. These results allow extension of the calibration equation to the quantification of unknown water contents within other samples of porous media.

  17. Water calibration measurements for neutron radiography: Application to water content quantification in porous media

    NASA Astrophysics Data System (ADS)

    Kang, M.; Bilheux, H. Z.; Voisin, S.; Cheng, C. L.; Perfect, E.; Horita, J.; Warren, J. M.

    2013-04-01

    Using neutron radiography, the measurement of water thickness was performed using aluminum (Al) water calibration cells at the High Flux Isotope Reactor (HFIR) Cold-Guide (CG) 1D neutron imaging facility at Oak Ridge National Laboratory, Oak Ridge, TN, USA. Calibration of water thickness is an important step to accurately measure water contents in samples of interest. Neutron attenuation by water does not vary linearly with thickness mainly due to beam hardening and scattering effects. Transmission measurements for known water thicknesses in water calibration cells allow proper correction of the underestimation of water content due to these effects. As anticipated, strong scattering effects were observed for water thicknesses greater than 0.2 cm when the water calibration cells were positioned close to the face of the detector/scintillator (0 and 2.4 cm away, respectively). The water calibration cells were also positioned 24 cm away from the detector face. These measurements resulted in less scattering and this position (designated as the sample position) was used for the subsequent experimental determination of the neutron attenuation coefficient for water. Neutron radiographic images of moist Flint sand in rectangular and cylindrical containers acquired at the sample position were used to demonstrate the applicability of the water calibration. Cumulative changes in the water volumes within the sand columns during monotonic drainage determined by neutron radiography were compared with those recorded by direct reading from a burette connected to a hanging water column. In general, the neutron radiography data showed very good agreement with those obtained volumetrically using the hanging water-column method. These results allow extension of the calibration equation to the quantification of unknown water contents within other samples of porous media.

  18. The effect of water purification systems on fluoride content of drinking water.

    PubMed

    Prabhakar, A R; Raju, O S; Kurthukoti, A J; Vishwas, T D

    2008-03-01

    The purpose of the present study was to determine the effect of different water purification systems on the fluoride content of drinking water and to compare the efficacy of these water purification systems in reducing the fluoride content. Five different water purification systems were tested in this study. They were reverse osmosis, distillation, activated carbon, Reviva , and candle filter. The water samples in the study were of two types, viz, borewell water and tap water, these being commonly used by the people of Davangere City, Karnataka. The samples were collected before and after purification, and fluoride analysis was done using fluoride ion-specific electrode. The results showed that the systems based on reverse osmosis, viz, reverse osmosis system and Reviva showed maximum reduction in fluoride levels, the former proving to be more effective than the latter; followed by distillation and the activated carbon system, with the least reduction being brought about by candle filter. The amount of fluoride removed by the purification system varied between the system and from one source of water to the other. Considering the beneficial effects of fluoride on caries prevention; when drinking water is subjected to water purification systems that reduce fluoride significantly below the optimal level, fluoride supplementation may be necessary. The efficacy of systems based on reverse osmosis in reducing the fluoride content of water indicates their potential for use as defluoridation devices.

  19. Effect of reducing dietary mineral content on growth performance, water intake, excreta dry matter content and blood parameters of broilers.

    PubMed

    Ziaei, N; Guy, J H; Edwards, S A; Blanchard, P J; Ward, J; Feuerstein, D

    2008-03-01

    1. The objective of this study was to investigate whether it is possible to reduce phosphorus (P) excretion by feeding a lower level of dietary P than that currently recommended, without compromising welfare, and whether this is sensitive to the level of dietary calcium (Ca). 2. A randomised complete block design was used with a total of 224 1-d-old male chicks of a commercial genotype in two batches. Chicks had a 10-d adaptation period. After this, they were moved to cages and allocated to one of 4 dietary treatments (4 and 3 birds per cage in batch 1 and 2, respectively). A standard level of Ca and P (8.3 and 6.6 g/kg, respectively) was compared with three lower levels of Ca (7.3, 6.3 and 5.3 g/kg) all at the same reduced level of P (5.5 g/kg). Records were made of live weight of birds on an individual basis and feed and water consumption on a cage basis. Every 7 d, the dry matter (DM) content of a sample of mixed excreta from each cage was measured. Birds were slaughtered and samples taken for analysis of plasma mineral content, retention of N, Ca and P and tibia bone strength. 3. The initial reduction in dietary mineral level did not adversely affect performance or bone strength. However, decreasing dietary Ca level below 7.3 g/kg, at constant P, led to reduced feed consumption and bone strength. Dietary treatment had no significant overall effect on water intake, water : feed ratio, excreta DM content, Ca and P retention or metabolisability of DM. There was no significant correlation between mean plasma Ca or P level and DM content of rectal digesta. 4. In conclusion, reducing dietary P from 6.6 to 5.5 g/kg to reduce potential environmental impact of broiler production had an adverse effect on bird welfare when the level of Ca was reduced below 7.3 g/kg, as a result of decreased feed intake in the early growth period and reduced skeletal strength.

  20. Electrokinetics dependence on water-content: laboratory and field approach

    NASA Astrophysics Data System (ADS)

    Allègre, Vincent; Sénéchal, Pascale; Lehmann, François; Bordes, Clarisse; Jouniaux, Laurence; Sailhac, Pascal; Bano, Maksim

    2010-05-01

    Electrokinetics results from the coupling between the water flow and the electrical current through the electrokinetic coefficient. The Self-Potential (SP) method, which is based on this phenomenon, is currently used to investigate shallow transport in the vadose zone. Thus, the understanding of the electrokinetic coefficient behaviour in unsaturated conditions is crucial to interpret such methods. Empirical and theoretical models proposed in the literature to describe this behaviour are still discussed. Consequently, physical processes involved in the electrokinetic coefficient behaviour in unsaturated conditions need to be futher investigate. We propose here to study the electrokinetics dependence on water content through an experimental approach and the numerical solving of the Richards' equation. We show several continuous records of the electrokinetic coefficient as a function of water saturation. We found that the normalized electrokinetic coefficient behaviour in unsaturated conditions is more complex than it was previously proposed. Indeed, we first observed its increasing with decreasing water saturation. After it reaches a maximum, identified around 80 % of water saturation, it begins to decrease with decreasing saturation. It is an important result since previous works predicted a monotically decreasing of the electrokinetic coefficient with decreasing saturation. We found that the normalized value of the measured electrokinetic coefficient could be two orders of magnitude greater than the classical value in saturated conditions, Csat. We performed several experiments and tried to invert the electrokinetic coefficient data and interpret it in terms of physical processes. We also propose a field study through several geophysical methods, as electrical resistivity tomography, seismoelectrics, and GPR, in order to combine the results in terms of water-content dependence in soils.

  1. Estimating plant available water content from remotely sensed evapotranspiration

    NASA Astrophysics Data System (ADS)

    van Dijk, A. I. J. M.; Warren, G.; Doody, T.

    2012-04-01

    Plant available water content (PAWC) is an emergent soil property that is a critical variable in hydrological modelling. PAWC determines the active soil water storage and, in water-limited environments, is the main cause of different ecohydrological behaviour between (deep-rooted) perennial vegetation and (shallow-rooted) seasonal vegetation. Conventionally, PAWC is estimated for a combination of soil and vegetation from three variables: maximum rooting depth and the volumetric water content at field capacity and permanent wilting point, respectively. Without elaborate local field observation, large uncertainties in PAWC occur due to the assumptions associated with each of the three variables. We developed an alternative, observation-based method to estimate PAWC from precipitation observations and CSIRO MODIS Reflectance-based Evapotranspiration (CMRSET) estimates. Processing steps include (1) removing residual systematic bias in the CMRSET estimates, (2) making spatially appropriate assumptions about local water inputs and surface runoff losses, (3) using mean seasonal patterns in precipitation and CMRSET to estimate the seasonal pattern in soil water storage changes, (4) from these, calculating the mean seasonal storage range, which can be treated as an estimate of PAWC. We evaluate the resulting PAWC estimates against those determined in field experiments for 180 sites across Australia. We show that the method produces better estimates of PAWC than conventional techniques. In addition, the method provides detailed information with full continental coverage at moderate resolution (250 m) scale. The resulting maps can be used to identify likely groundwater dependent ecosystems and to derive PAWC distributions for each combination of soil and vegetation type.

  2. Dielectric constant and low-frequency infrared spectra for liquid water and ice Ih within the E3B model

    SciTech Connect

    Shi, L.; Ni, Y.; Drews, S. E. P.; Skinner, J. L.

    2014-08-28

    Two intrinsic difficulties in modeling condensed-phase water with conventional rigid non-polarizable water models are: reproducing the static dielectric constants for liquid water and ice Ih, and generating the peak at about 200 cm{sup −1} in the low-frequency infrared spectrum for liquid water. The primary physical reason for these failures is believed to be the missing polarization effect in these models, and consequently various sophisticated polarizable water models have been developed. However, in this work we pursue a different strategy and propose a simple empirical scheme to include the polarization effect only on the dipole surface (without modifying a model's intermolecular interaction potential). We implement this strategy for our explicit three-body (E3B) model. Our calculated static dielectric constants and low-frequency infrared spectra are in good agreement with experiment for both liquid water and ice Ih over wide temperature ranges, albeit with one fitting parameter for each phase. The success of our modeling also suggests that thermal fluctuations about local minima and the energy differences between different proton-disordered configurations play minor roles in the static dielectric constant of ice Ih. Our analysis shows that the polarization effect is important in resolving the two difficulties mentioned above and sheds some light on the origin of several features in the low-frequency infrared spectra for liquid water and ice Ih.

  3. Runoff simulation sensitivity to remotely sensed initial soil water content

    NASA Astrophysics Data System (ADS)

    Goodrich, D. C.; Schmugge, T. J.; Jackson, T. J.; Unkrich, C. L.; Keefer, T. O.; Parry, R.; Bach, L. B.; Amer, S. A.

    1994-05-01

    A variety of aircraft remotely sensed and conventional ground-based measurements of volumetric soil water content (SW) were made over two subwatersheds (4.4 and 631 ha) of the U.S. Department of Agriculture's Agricultural Research Service Walnut Gulch experimental watershed during the 1990 monsoon season. Spatially distributed soil water contents estimated remotely from the NASA push broom microwave radiometer (PBMR), an Institute of Radioengineering and Electronics (IRE) multifrequency radiometer, and three ground-based point methods were used to define prestorm initial SW for a distributed rainfall-runoff model (KINEROS; Woolhiser et al., 1990) at a small catchment scale (4.4 ha). At a medium catchment scale (631 ha or 6.31 km2) spatially distributed PBMR SW data were aggregated via stream order reduction. The impacts of the various spatial averages of SW on runoff simulations are discussed and are compared to runoff simulations using SW estimates derived from a simple daily water balance model. It was found that at the small catchment scale the SW data obtained from any of the measurement methods could be used to obtain reasonable runoff predictions. At the medium catchment scale, a basin-wide remotely sensed average of initial water content was sufficient for runoff simulations. This has important implications for the possible use of satellite-based microwave soil moisture data to define prestorm SW because the low spatial resolutions of such sensors may not seriously impact runoff simulations under the conditions examined. However, at both the small and medium basin scale, adequate resources must be devoted to proper definition of the input rainfall to achieve reasonable runoff simulations.

  4. Fluoride and bacterial content of bottled drinking water versus municipal tap water.

    PubMed

    Mythri, H; Chandu, G N; Prashant, G M; Subba Reddy, V V

    2010-01-01

    Water is a divine gift. People quench their thirst without questioning the source of water. But, apprehension about contaminants in municipal water supplies along with increased fear of fluorosis made bottled drinking water as one of the important tradable commodities. The objectives of the study were to determine and compare the fluoride and bacterial contents of commercially available bottled drinking water and municipal tap water in Davangere city, Karnataka. Fifty samples of 10 categories of bottled drinking water with different batch numbers were purchased and municipal water from different sources were collected. Fluoride levels were determined by an ion-selective electrode. Water was cultured quantitatively and levels of bacteria were calculated as colony-forming units (CFUs) per milliliter. Descriptive analysis of water samples for fluoride concentration was in the range of 0.07-0.33 for bottled drinking water, Bisleri showing the highest of 0.33. A comparison of the mean values of microbial count for bottled drinking water with that of municipal tap water showed no statistically significant difference, but was more than the standard levels along with the presence of fungus and maggots. The fluoride concentration was below the optimal level for both municipal tap water and bottled drinking water. CFUs were more than the recommended level in both municipal tap water and bottled drinking water.

  5. Both water intoxication and osmotic BBB disruption increase brain water content in rats.

    PubMed

    Kozler, P; Riljak, V; Pokorný, J

    2013-01-01

    Our previous experiments revealed that water intoxication and osmotic BBB disruption in the rat allow penetration of high-molecular substances into the brain and that resulting changes in the internal environment of the CNS lead to pathological development, such as the loss of integrity of myelin. The aim of the present study was to determine whether the previously described phenomena are associated with increased water content in the brain. To answer the question following methods were used: a) water intoxication: intraperitoneal administration of distilled water, b) osmotic BBB disruption: application of mannitol (20 %) selectively into the internal carotid artery, c) brain wet weight was measured after decapitation, and subsequently (after six days in thermostat set at 86 °C) the dry weight were estimated d) in animals with 20 % and 30 % hyperhydration the degree of myelin deterioration was estimated e) animal locomotor activity was tested by continuous behavior tracking and analysis. Brain water content after water intoxication and following the administration of mannitol was higher than in the control group. Different degrees of hyperhydration led to different levels of brain water content and to different degrees of myelin impairment. Hyperhydration corresponding to 20 % of the body weight brought about lower locomotor activity. Increased water content in the brain after the BBB osmotic disruption is surprising because this method is frequently used in the clinical practice.

  6. Performance evaluation of TDT soil water content and watermark soil water potential sensors

    USDA-ARS?s Scientific Manuscript database

    This study evaluated the performance of digitized Time Domain Transmissometry (TDT) soil water content sensors (Acclima, Inc., Meridian, ID) and resistance-based soil water potential sensors (Watermark 200, Irrometer Company, Inc., Riverside, CA) in two soils. The evaluation was performed by compar...

  7. Effects of water stress on respiration, photosynthetic pigments and water content in two maize cultivars.

    PubMed

    Mohammadkhani, Nayer; Heidari, Reza

    2007-11-15

    Water stress is one of the most important environmental factors that reduce growth, development and production of plants. Stress was applied with polyethyleneglycol (PEG) 6000 and water potentials were: zero (control), -0.15 (PEG 10%), -0.49 (PEG 20%), -1.03 (PEG 30%) and -1.76 (PEG 40%) MPa. The roots and leaves respiration of two maize (Zea mays L.) cultivars -704 and 301- were determined in various concentrations of PEG 6000. Oxygen uptake declined in leaves and roots with increasing PEG concentrations. Decrease of oxygen uptake in roots and leaves of 704 variety were higher than 301 variety. Chlorophyll a, b and total chlorophyll content were significantly decreased (p < 0.05), but carotenoids content increased (p < 0.05) under water stress. Decrease of chlorophyll content in 704 var. was higher than 301 var., but carotenoids content in 301 var. was higher than 704 var. Relative Water Content (RWC) was used to indicate the degree of stress. RWC decreased with increasing PEG concentrations. Lowering of RWC reduced growth and increased shoot/root ratio. Decrease of water content in 704 plants was higher than 301 plants. Shoot/root ratio in 704 var. was higher than 301 var.

  8. Disparate effects of constant and annually-cycling daylength and water temperature on reproductive maturation of striped bass (Morone saxatilis)

    USGS Publications Warehouse

    Clark, R.W.; Henderson-Arzapalo, A.; Sullivan, C.V.

    2005-01-01

    Adult striped bass (Morone saxatilis) were exposed to various combinations of constant or anually-cycling daylength and water temperature. Constant conditions (15 h days, 18??C) were those normally experienced at spawning and cycling conditions simulated natural changes at Chesapeake Bay latitude. Females exposed to constant long (15 h) days and cycling water temperature (TEMPERATURE group) had blood plasma levels of sex steroids (testosterone [T] and estradiol-17?? [E2]) and vitellogenin (Vg), and profiles of oocyte growth, that were nearly identical to those of females held under a natural photothermal cycle (CONTROL group). Several fish from these two groups were induced to spawn fertile eggs. Females constantly exposed to warm water (18??C), with or without a natural photoperiod cycle (PHOTOPERIOD and STATIC groups, respectively), had diminished circulating levels of gonadal steroid hormones and Vg, impaired deposition of yolk granules in their ooplasm, and decreased oocyte growth, and they underwent premature ovarian atresia. Males exposed to cycling water temperature (CONTROL and TEMPERATURE groups) spermiated synchronously during the natural breeding season, at which time they also had had high plasma androgen (T and 11-ketotestosterone [11-KT]) levels. The timing of spermiation was highly asynchronous among males in groups of fish held constantly at 18??C (STATIC and PHOTOPERIOD groups) and this asynchrony was associated with diminished plasma androgen levels. Termination of spermiation by males exposed to cycling water temperature coincided with a sharp decline in levels of plasma androgens about a month after water temperature rose above 18??C. In contrast, most males held constantly at 18??C sustained intermediate levels of plasma androgens and spermiated until the end of the study in late July. The annual cycle of water temperature clearly plays a prominent role in the initiation, maintenance, and termination of the striped bass reproductive cycle. In

  9. Mineral and water content of A. gigas scales determine local micromechanical properties and energy dissipation mechanisms

    NASA Astrophysics Data System (ADS)

    Troncoso, Omar P.; Gigos, Florian; Torres, Fernando G.

    2017-03-01

    Arapaima gigas scales are natural laminated composite materials made of individual layers with different degrees of mineralization, accompanied of varying mechanical properties. This natural design provides scales with hardness and flexibility, and can serve as a source of inspiration for the development of new layered composites with a hard surface and flexible base. In this paper, we have carried out cyclic micro-indentation tests on both; the internal and the highly mineralized external surface of air dried and wet scales, in order to assess the variation of their local micromechanical properties with regard to the mineral and water content. The load-penetration (P-h) curves showed that creep takes place throughout the application of a constant force during the micro-indentation tests, confirming the time dependent response of A. gigas scales. A model that accounted for the elastic, plastic and viscous responses of the samples was used to fit the experimental results. The penetration depth during loading and creep, as well as the energy dissipated are dependent on the water content. The used model suggests that the viscous response of the internal layer increases with the water content.

  10. Non-destructive detection of water stress and estimation of relative water content in maize

    NASA Astrophysics Data System (ADS)

    Zygielbaum, Arthur I.; Gitelson, Anatoly A.; Arkebauer, Timothy J.; Rundquist, Donald C.

    2009-06-01

    Non-destructive estimation of leaf water content provides vital information about vegetation productivity. We report here on controlled seven day experiments using greenhouse-grown maize. Fifty plants were randomly assigned to two equal groups: water stressed and well watered. Spectroscopic, relative water content (RWC), and chlorophyll concentration measurements were made daily. Because water molecules absorb radiation in near- and middle-infrared, most efforts to sense water deficit remotely utilize infrared wavelengths. In these experiments, we identified a strong, systematic, and repeatable relationship between photosynthetically active radiation (PAR, 400-700 nm) albedo and leaf RWC. We show that visible spectrum reflectance provides a means to detect early stages of plant stress and estimate leaf RWC.

  11. Hygienic importance of increased barium content in some fresh waters.

    PubMed

    Havlík, B; Hanusová, J; Rálková, J

    1980-01-01

    In surface waters of the mining and processing areas of uranium ore there is an increased content of free and bound barium ions due to the use of barium salts for the treatment of waste and mine waters containing radium. In model experiments with the algae Ankistrodesmus falcatus, Chlorella kessleri and Scenedesmus obliquus, we studied the effect of Ba2+ on the accumulation of 226Ra. It was found that the accumulation of radium by algae is negatively influenced with barium concentrations higher than 1 mg.l-1. The accumulation of barium of organisms of primary production was studied using 133BaCl2. At a barium content in the medium of 4.0, 0.46 and 0.04 mu. l-1, the algae accumulated 30-60% of the added amount of barium during an exposure of 15 days. Biochemical analyses showed that barium is bound to the cellular membrane and to other components of the algal cell that cannot be extracted with water or alcohol.

  12. Stalagmite water content as a proxy for drip water supply in tropical and subtropical areas

    NASA Astrophysics Data System (ADS)

    Vogel, N.; Scheidegger, Y.; Brennwald, M. S.; Fleitmann, D.; Figura, S.; Wieler, R.; Kipfer, R.

    2012-07-01

    In this pilot study water was extracted from samples of two Holocene stalagmites from Socotra Island, Yemen, and one Eemian stalagmite from southern continental Yemen. The amount of water extracted per unit mass of stalagmite rock, termed "water yield" hereafter, serves as a measure for its total water content. The stalagmites' water yield records vary systematically with the corresponding oxygen isotopic compositions of the calcite (δ18Ocalcite). Low δ18Ocalcite values are thereby accompanied by low water yields and vice versa. Based on the paleoclimatic interpretation of the δ18Ocalcite records, water yields can be linked to drip water supply. High drip water supply caused by high precipitation rates supports homogeneous deposition of calcite with low porosity and therefore a small fraction of water-filled inclusions, resulting in low water yields of the respective samples. A reduction of drip water supply fosters irregular growth of calcite with higher porosity, leading to an increase of the fraction of water-filled inclusions and thus higher water yields. The results are consistent with the literature on stalagmite growth and supported by optical inspection of thin sections of our samples. We propose that for a stalagmite from a tropical or subtropical area, its water yield record represents a novel paleoclimate proxy recording changes in drip water supply, which can in turn be interpreted in terms of associated precipitation rates.

  13. On the Variation of Water Diffusion Coefficient in Stratum Corneum With Water Content.

    PubMed

    Li, Xin; Johnson, Robert; Kasting, Gerald B

    2016-03-01

    Water permeability and transient water sorption data in human and porcine stratum corneum (SC) are analyzed in conjunction with equilibrium water sorption data and a dynamic skin swelling model to develop a quantitative model for water diffusivity in the SC as a function of its water content. The recommended function (model 1) is phenomenological and treats the SC as a uniform, swellable slab. This approach yields satisfactory agreement with experimental data over a wide range of RH and associated equilibrium SC water content, Cw. It is supported by two alternative approaches. Model 2 considers the SC to be a multilaminate membrane consisting of alternating lipid and protein layers. Diffusivity in the protein phase is estimated from water diffusivity in other keratinized tissues, whereas diffusivity in the lipid phase is assumed to be linearly related to the swelling strain on intercellular lipids. Model 3 uses an analysis previously suggested by Stockdale to rationalize transepidermal water loss data in humans over a wide range of relative humidity. All models yield similar results for 0.20 ≤ Cw ≤ 0.78 g/cm(3), the usual range of SC water content in vivo. Copyright © 2016. Published by Elsevier Inc.

  14. Liposome/water lipophilicity: methods, information content, and pharmaceutical applications.

    PubMed

    van Balen, Georgette Plemper; Martinet, Catherine a Marca; Caron, Giulia; Bouchard, Géraldine; Reist, Marianne; Carrupt, Pierre-Alain; Fruttero, Roberta; Gasco, Alberto; Testa, Bernard

    2004-05-01

    This review discusses liposome/water lipophilicity in terms of the structure of liposomes, experimental methods, and information content. In a first part, the structural properties of the hydrophobic core and polar surface of liposomes are examined in the light of potential interactions with solute molecules. Particular emphasis is placed on the physicochemical properties of polar headgroups of lipids in liposomes. A second part is dedicated to three useful methods to study liposome/water partitioning, namely potentiometry, equilibrium dialysis, and (1)H-NMR relaxation rates. In each case, the principle and limitations of the method are discussed. The next part presents the structural information encoded in liposome/water lipophilicity, in other words the solutes' structural and physicochemical properties that determine their behavior and hence their partitioning in such systems. This presentation is based on a comparison between isotropic (i.e., solvent/water) and anisotropic (e.g., liposome/water) systems. An important factor to be considered is whether the anisotropic lipid phase is ionized or not. Three examples taken from the authors' laboratories are discussed to illustrate the factors or combinations thereof that govern liposome/water lipophilicity, namely (a) hydrophobic interactions alone, (b) hydrophobic and polar interactions, and (c) conformational effects plus hydrophobic and ionic interactions. The next part presents two studies taken from the field of QSAR to exemplify the use of liposome/water lipophilicity in structure-disposition and structure-activity relationships. In the conclusion, we summarize the interests and limitations of this technology and point to promising developments.

  15. REMOTE ANALYSIS OF HIGH-TRITIUM-CONTENT WATER

    SciTech Connect

    Diprete, D; Raymond Sigg, R; Leah Arrigo, L; Donald Pak, D

    2007-08-07

    Systems to safely analyze for tritium in moisture collected from glovebox atmospheres are being developed for use at Savannah River Site (SRS) tritium facilities. Analysis results will guide whether the material contains sufficient tritium for economical recovery, or whether it should be stabilized for disposal as waste. In order to minimize potential radiation exposures that could occur in handling and diluting high-tritium-content water, SRS sought alternatives to the process laboratory's routine analysis by liquid-scintillation counting. The newer systems determine tritium concentrations by measuring bremsstrahlung radiation induced by low-energy beta interactions. One of the systems determines tritium activity in liquid streams, the other determines tritium activity in water vapor. Topics discussed include counting results obtained by modeling and laboratory testing and corrections that are made for low-energy photon attenuation.

  16. Design of multiscale soil water content monitoring networks

    NASA Astrophysics Data System (ADS)

    Franz, T. E.

    2016-12-01

    The need for accurate, real-time, reliable, and multi-scale soil water content monitoring is critical for a multitude of scientific disciplines trying to understand and predict the earth's terrestrial energy, water, and nutrient cycles. One promising technique to help meet this demand is fixed and roving cosmic-ray neutron probes. In this work I will present recent advances in the roving method including the incorporation of globally available datasets for use in long transects or austere environments. In addition, I will layout potential strategies on new network design, incorporation of existing infrastructure from multiple sensor types, and appropriate use of cosmic-ray neutron data in assimilation frameworks. Specific examples from agricultural applications in the Midwestern United States will be highlighted.

  17. Effect of water content on the water repellency for hydrophobized sands

    NASA Astrophysics Data System (ADS)

    Subedi, S.; Kawamoto, K.; Kuroda, T.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Alternative earthen covers such as capillary barriers (CBs) and evapotranspirative covers are recognized as useful technical and low-cost solutions for limiting water infiltration and controlling seepage flow at solid waste landfills in semi-arid and arid regions. However, their application to the landfills at wet regions seems to be matter of concern due to loss of their impending capability under high precipitation. One of the possible techniques to enhance the impermeable properties of CBs is to alter soil grain surfaces to be water-repellent by mixing/coating hydrophobic agents (HAs). In order to examine a potential use of model sands hydrophobized with locally available and environmental-friendly HAs such as oleic acid (OA) and stearic acid (SA) for hydrophobic CBs. In the present study, we first characterized the effect of water content on the degree of water repellency (WR) for hydrophobized sands and volcanic ash soil at different depth. Secondly, the time dependency of the contact angle in hydrophobized sands and volcanic ash soils at different water content was evaluated. Further, the effects of hydrophobic organic matter contents on the WR of hydrophobized sands were investigated by horizontal infiltration test. We investigated the degree of WR as functions of volumetric water content (θ) of a volcanic ash soil samples from different depth and water adjusted hydrophobized sand samples with different ratio of HAs by using sessile drop method (SDM). The initial contact angle (αi) measured from SDM decreased gradually with increasing water content in OA and SA coated samples. Measured αi values for volcanic ash soils increased with increasing water content and reached a peak values of 111.7o at θ= 0.325 cm3 cm-3, where-after αi gradually decreased. Each test sample exhibited sharp decrease in contact angle with time at higher water content. Sorptivity values for oleic acid coated samples decreased with increasing HA content and reached the minimum

  18. Estimating canopy water content using hyperspectral remote sensing data

    NASA Astrophysics Data System (ADS)

    Clevers, J. G. P. W.; Kooistra, L.; Schaepman, M. E.

    2010-04-01

    Hyperspectral remote sensing has demonstrated great potential for accurate retrieval of canopy water content (CWC). This CWC is defined by the product of the leaf equivalent water thickness (EWT) and the leaf area index (LAI). In this paper, in particular the spectral information provided by the canopy water absorption feature at 970 nm for estimating and predicting CWC was studied using a modelling approach and in situ spectroradiometric measurements. The relationship of the first derivative at the right slope of the 970 nm water absorption feature with CWC was investigated with the PROSAIL radiative transfer model and tested for field spectroradiometer measurements on two test sites. The first site was a heterogeneous floodplain with natural vegetation like grasses and various shrubs. The second site was an extensively grazed fen meadow. PROSAIL simulations (using coupled SAIL/PROSPECT-5 models) showed a linear relationship between the first derivative over the 1015-1050 nm spectral interval and CWC ( R2 = 0.97). For 8 plots at the floodplain site the spectral derivative over the 1015-1050 nm interval obtained with an ASD FieldSpec spectroradiometer yielded an R2 of 0.51 with CWC. For 40 plots at the fen meadow ASD FieldSpec spectral measurements yielded an R2 of 0.68 for the derivative over the 1015-1050 nm interval with CWC. Consistency of the results confirmed the potential of using simulation results for calibrating the relationship between this first derivative and CWC.

  19. Nuclear magnetic resonance imaging of water content in the subsurface

    SciTech Connect

    J. Hendricks; T. Yao; A. Kearns

    1999-01-21

    Previous theoretical and experimental studies indicated that surface nuclear magnetic resonance (NMR) has the potential to provide cost-effective water content measurements in the subsurface and is a technology ripe for exploitation in practice. The objectives of this investigation are (a) to test the technique under a wide range of hydrogeological conditions and (b) to generalize existing NMR theories in order to correctly model NMR response from conductive ground and to assess properties of the inverse problem. Twenty-four sites with different hydrogeologic settings were selected in New Mexico and Colorado for testing. The greatest limitation of surface NMR technology appears to be the lack of understanding in which manner the NMR signal is influenced by soil-water factors such as pore size distribution, surface-to-volume ratio, paramagnetic ions dissolved in the ground water, and the presence of ferromagnetic minerals. Although the theoretical basis is found to be sound, several advances need to be made to make surface NMR a viable technology for hydrological investigations. There is a research need to investigate, under controlled laboratory conditions, how the complex factors of soil-water systems affect NMR relaxation times.

  20. Mechanical impedance of soil crusts and water content in loamy soils

    NASA Astrophysics Data System (ADS)

    Josa March, Ramon; Verdú, Antoni M. C.; Mas, Maria Teresa

    2013-04-01

    Soil crust development affects soil water dynamics and soil aeration. Soil crusts act as mechanical barriers to fluid flow and, as their mechanical impedance increases with drying, they also become obstacles to seedling emergence. As a consequence, the emergence of seedling cohorts (sensitive seeds) might be reduced. However, this may be of interest to be used as an effective system of weed control. Soil crusting is determined by several factors: soil texture, rain intensity, sedimentation processes, etc. There are different ways to characterize the crusts. One of them is to measure their mechanical impedance (MI), which is linked to their moisture level. In this study, we measured the evolution of the mechanical impedance of crusts formed by three loamy soil types (clay loam, loam and sandy clay loam, USDA) with different soil water contents. The aim of this communication was to establish a mathematical relationship between the crust water content and its MI. A saturated soil paste was prepared and placed in PVC cylinders (50 mm diameter and 10 mm height) arranged on a plastic tray. Previously the plastic tray was sprayed with a hydrophobic liquid to prevent the adherence of samples. The samples on the plastic tray were left to air-dry under laboratory conditions until their IM was measured. To measure IM, a food texture analyzer was used. The equipment incorporates a mobile arm, a load cell to apply force and a probe. The arm moves down vertically at a constant rate and the cylindrical steel probe (4 mm diameter) penetrates the soil sample vertically at a constant rate. The equipment is provided with software to store data (time, vertical distance and force values) at a rate of up to 500 points per second. Water content in crust soil samples was determined as the loss of weight after oven-drying (105°C). From the results, an exponential regression between MI and the water content was obtained (determination coefficient very close to 1). This methodology allows

  1. Spatial Irrigation Management Using Remote Sensing Water Balance Modeling and Soil Water Content Monitoring

    NASA Astrophysics Data System (ADS)

    Barker, J. Burdette

    Spatially informed irrigation management may improve the optimal use of water resources. Sub-field scale water balance modeling and measurement were studied in the context of irrigation management. A spatial remote-sensing-based evapotranspiration and soil water balance model was modified and validated for use in real-time irrigation management. The modeled ET compared well with eddy covariance data from eastern Nebraska. Placement and quantity of sub-field scale soil water content measurement locations was also studied. Variance reduction factor and temporal stability were used to analyze soil water content data from an eastern Nebraska field. No consistent predictor of soil water temporal stability patterns was identified. At least three monitoring locations were needed per irrigation management zone to adequately quantify the mean soil water content. The remote-sensing-based water balance model was used to manage irrigation in a field experiment. The research included an eastern Nebraska field in 2015 and 2016 and a western Nebraska field in 2016 for a total of 210 plot-years. The response of maize and soybean to irrigation using variations of the model were compared with responses from treatments using soil water content measurement and a rainfed treatment. The remote-sensing-based treatment prescribed more irrigation than the other treatments in all cases. Excessive modeled soil evaporation and insufficient drainage times were suspected causes of the model drift. Modifying evaporation and drainage reduced modeled soil water depletion error. None of the included response variables were significantly different between treatments in western Nebraska. In eastern Nebraska, treatment differences for maize and soybean included evapotranspiration and a combined variable including evapotranspiration and deep percolation. Both variables were greatest for the remote-sensing model when differences were found to be statistically significant. Differences in maize yield in

  2. Oxy-combustion of high water content fuels

    NASA Astrophysics Data System (ADS)

    Yi, Fei

    As the issues of global warming and the energy crisis arouse extensive concern, more and more research is focused on maximizing energy efficiency and capturing CO2 in power generation. To achieve this, in this research, we propose an unconventional concept of combustion - direct combustion of high water content fuels. Due to the high water content in the fuels, they may not burn under air-fired conditions. Therefore, oxy-combustion is applied. Three applications of this concept in power generation are proposed - direct steam generation for the turbine cycle, staged oxy-combustion with zero flue gas recycle, and oxy-combustion in a low speed diesel-type engine. The proposed processes could provide alternative approaches to directly utilize fuels which intrinsically have high water content. A large amount of energy to remove the water, when the fuels are utilized in a conventional approach, is saved. The properties and difficulty in dewatering high water content fuels (e.g. bioethanol, microalgae and fine coal) are summarized. These fuels include both renewable and fossil fuels. In addition, the technique can also allow for low-cost carbon capture due to oxy-combustion. When renewable fuel is utilized, the whole process can be carbon negative. To validate and evaluate this concept, the research focused on the investigation of the flame stability and characteristics for high water content fuels. My study has demonstrated the feasibility of burning fuels that have been heavily diluted with water in a swirl-stabilized burner. Ethanol and 1-propanol were first tested as the fuels and the flame stability maps were obtained. Flame stability, as characterized by the blow-off limit -- the lowest O2 concentration when a flame could exist under a given oxidizer flow rate, was determined as a function of total oxidizer flow rate, fuel concentration and nozzle type. Furthermore, both the gas temperature contour and the overall ethanol concentration in the droplets along the

  3. Water and electrolyte content of the myofilament phase in the chemically skinned barnacle fiber

    PubMed Central

    1980-01-01

    Muscle fibers from the giant barnacle, Balanus nubilus, were placed inside the lumen of a porous glass capillary and equilibrated for 48 h in an electrolyte solution containing 2% Tween. The glass capillary prevented the chemically "skinned" fiber from swelling with a water content beyond 80%. Isotope exchange studies using 22Na, 42K, and 36Cl indicated the existence of an intermediate rate constant and compartment which varied with pH. This intermediate rate was attributed to counter-ions and co-ions in the myofilament phase. Analysis of the electrolyte composition of the fiber at pH 8 predicts that the myofilaments contain about 0.3 of the fiber water, and that a -15 mV Donnan potential exists at the myofilament surface. An open-tipped (1- micrometer) microelectrode in the skinned fiber measured a potential (similar in magnitude to the Donnan potential), which decreased and reversed sign as the pH was lowered. The measured cation contents of the fiber between pH 5 and 8 were found to be similar to the cation contents predicted from the measured Donnan potentials. The net negative charge of the myofilaments at pH 7.5 and at ionic strength 0.56 is estimated to be 41 eq per 10(5) g of dry weight. PMID:7189772

  4. Relationship between optical extinction and liquid water content in fogs

    NASA Astrophysics Data System (ADS)

    Klein, C.; Dabas, A.

    2014-05-01

    Studies carried out in the late 1970s suggest that a simple linear relationship exists in practice between the optical extinction in the thermal IR and the liquid water content (LWC) in fogs. Such a relationship opens the possibility to monitor the vertical profile of the LWC in fogs with a rather simple backscatter lidar. Little is known on how the LWC varies as a function of height and during the fog life cycle, so the new measurement technique would help understand fog physics and provide valuable data for improving the quality of fog forecasts. In this paper, the validity of the linear relationship is revisited in the light of recent observations of fog droplet size distributions measured with a combination of sensors covering a large range of droplet radii. In particular, large droplets (radius above 15 μm) are now detected, which was not the case in the late 1970s. The results confirm that the linear relationship still holds, at least for the mostly radiative fogs observed during the campaign. The impact of the precise value of the real and imaginary parts of the refractive index on the coefficient of the linear relationship is also studied. The usual practice considers that droplets are made of pure water. This assumption is probably valid for big drops, but it may be questioned for small ones since droplets are formed from condensation nuclei of highly variable chemical composition. The study suggests that the precise nature of condensation nuclei will primarily affect rather light fogs with small droplets and light liquid water contents.

  5. Characterization of soil water content variability and soil texture using GPR groundwave techniques

    SciTech Connect

    Grote, K.; Anger, C.; Kelly, B.; Hubbard, S.; Rubin, Y.

    2010-08-15

    Accurate characterization of near-surface soil water content is vital for guiding agricultural management decisions and for reducing the potential negative environmental impacts of agriculture. Characterizing the near-surface soil water content can be difficult, as this parameter is often both spatially and temporally variable, and obtaining sufficient measurements to describe the heterogeneity can be prohibitively expensive. Understanding the spatial correlation of near-surface soil water content can help optimize data acquisition and improve understanding of the processes controlling soil water content at the field scale. In this study, ground penetrating radar (GPR) methods were used to characterize the spatial correlation of water content in a three acre field as a function of sampling depth, season, vegetation, and soil texture. GPR data were acquired with 450 MHz and 900 MHz antennas, and measurements of the GPR groundwave were used to estimate soil water content at four different times. Additional water content estimates were obtained using time domain reflectometry measurements, and soil texture measurements were also acquired. Variograms were calculated for each set of measurements, and comparison of these variograms showed that the horizontal spatial correlation was greater for deeper water content measurements than for shallower measurements. Precipitation and irrigation were both shown to increase the spatial variability of water content, while shallowly-rooted vegetation decreased the variability. Comparison of the variograms of water content and soil texture showed that soil texture generally had greater small-scale spatial correlation than water content, and that the variability of water content in deeper soil layers was more closely correlated to soil texture than were shallower water content measurements. Lastly, cross-variograms of soil texture and water content were calculated, and co-kriging of water content estimates and soil texture

  6. Explicit equations for two-dimensional water waves with constant vorticity.

    PubMed

    Ruban, V P

    2008-03-01

    Governing equations for two-dimensional inviscid free-surface flows with constant vorticity over arbitrary nonuniform bottom profile are presented in exact and compact form using conformal variables. An efficient and very accurate numerical method for this problem is developed.

  7. Soil water content and green water estimations in a small farmed semiarid catchment

    NASA Astrophysics Data System (ADS)

    Mekki, I.; Voltz, M.; Ben Mechlia, N.; Albergel, J.

    2012-04-01

    The main objective of this work is to analyze the spatial and temporal variation of soil water content and green water production over a farmed water harvesting catchment, located in north-eastern Tunisia. The area has a typical Mediterranean climate with a hot dry summer and a cool season, extending from October to April, where rainfall normally meets the water requirements of the usually grown cereals and legumes (500mm). The catchment has an area of 2.6 km2 and comprises at its outlet a dam, which retains the runoff water in a reservoir. Soil water balance measurements were carried out, about weekly, over two successive cropping cycles (2000-2002) on a network of eleven plots of 2 m2 each, representing the main land use and soil types. Soil water store investigations targeted the different individual plots as well as the entire catchment. We used a simple water balance model, where the root zone is considered as a single reservoir, to simulate soil water content variations. Results show a fairly good agreement between the calculated and measured water store for all experimental sites. The model reproduces accurately the soil water content during the beginning of the rainy season but underestimates it during the season when heavy rains occur. On heavy soils, simulated soil moisture was lower than measured values, giving differences as high as 25% between simulated water store amounts and the neutron probe measurement values. For the cereals/legume/pasture based cropping systems, most of rainfall water is stored in the soil and returns to the atmosphere by evapotranspiration. The 0-0.3 m soil layer is most active for water uptake by crops and intermittent replenishment by rainfall during the growing period; whereas drying involves the entire soil profile over the summer season (May-Seeptmber). The available water holding capacity of the soil turned out to be about seven times the storage capacity of the reservoir, showing the order of magnitude of rainfall

  8. Soil water content plays an important role in soil-atmosphere exchange of carbonyl sulfide (OCS)

    NASA Astrophysics Data System (ADS)

    Yi, Zhigang; Behrendt, Thomas; Bunk, Rüdiger; Wu, Dianming; Kesselmeier, Jürgen

    2016-04-01

    Carbonyl sulfide (OCS) is a quite stable gas in the troposphere and is transported up to the stratosphere, where it contributes to the sulfate aerosol layer (Crutzen 1976). The tropospheric concentration seems to be quite constant, indicating a balance between sinks and sources. Recent work by Sandoval-Soto et al. (2005) demonstrated the enormous strength of the vegetation sink and the urgent needs to understand the sinks and sources. The role of soils is a matter of discussion (Kesselmeier et al., 1999; Van Diest and Kesselmeier, 2008; Maseyk et al., 2014; Whelan et al., 2015). To better understand the influence of soil water content and OCS mixing ratio on OCS fluxes, we used an OCS analyzer (LGR COS/CO Analyzer 907-0028, Los Gatos, CA, USA) coupled with automated soil chamber system (Behrendt et al., 2014) to measure the OCS fluxes with a slow drying of four different types of soil (arable wheat soil in Mainz, blueberry soil in Waldstein, spruce soil in Waldstein and needle forest soil in Finland). Results showed that OCS fluxes as well as the optimum soil water content for OCS uptake varied significantly for different soils. The net production rates changed significantly with the soil drying out from 100% to about 5% water holding capacity (WHC), implying that soil water content play an important role in the uptake processes. The production and uptake processes were distinguished by the regression of OCS fluxes under different OCS mixing ratios. OCS compensation points (CP) were found to differ significantly for different soil types and water content, with the lowest CP at about 20% WHC, implying that when estimating the global budgets of OCS, especially for soils fluxes, soil water content should be taken into serious consideration. References Crutzen, P. J. 1976, Geophys. Res. Lett., 3, 73-76. Sandoval-Soto, L. et al., 2005, Biogeosciences, 2, 125-132. Kesselmeier, J. et al., 1999, J. Geophys. Res., 104, 11577-11584. Van Diest, H. and Kesselmeier, J. 2008

  9. Sensing the water content of honey from temperature-dependent electrical conductivity

    USDA-ARS?s Scientific Manuscript database

    In order to predict water content in honey, electrical conductivity was measured on blossom honey types of milk-vetch, jujube and yellow-locust with water content of 18%-37% between 5-40ºC. Regression models of electrical conductivity were developed as functions of water content and temperature. The...

  10. Stalagmite water content as a proxy for drip water supply in tropical and subtropical areas

    NASA Astrophysics Data System (ADS)

    Vogel, N.; Scheidegger, Y.; Brennwald, M. S.; Fleitmann, D.; Figura, S.; Wieler, R.; Kipfer, R.

    2013-01-01

    In this pilot study water was extracted from samples of two Holocene stalagmites from Socotra Island, Yemen, and one Eemian stalagmite from southern continental Yemen. The amount of water extracted per unit mass of stalagmite rock, termed "water yield" hereafter, serves as a measure of its total water content. Based on direct correlation plots of water yields and δ18Ocalcite and on regime shift analyses, we demonstrate that for the studied stalagmites the water yield records vary systematically with the corresponding oxygen isotopic compositions of the calcite (δ18Ocalcite). Within each stalagmite lower δ18Ocalcite values are accompanied by lower water yields and vice versa. The δ18Ocalcite records of the studied stalagmites have previously been interpreted to predominantly reflect the amount of rainfall in the area; thus, water yields can be linked to drip water supply. Higher, and therefore more continuous drip water supply caused by higher rainfall rates, supports homogeneous deposition of calcite with low porosity and therefore a small fraction of water-filled inclusions, resulting in low water yields of the respective samples. A reduction of drip water supply fosters irregular growth of calcite with higher porosity, leading to an increase of the fraction of water-filled inclusions and thus higher water yields. The results are consistent with the literature on stalagmite growth and supported by optical inspection of thin sections of our samples. We propose that for a stalagmite from a dry tropical or subtropical area, its water yield record represents a novel paleo-climate proxy recording changes in drip water supply, which can in turn be interpreted in terms of associated rainfall rates.

  11. Long-term behavior of water content and density in an earthen liner

    USGS Publications Warehouse

    Frank, T.E.; Krapac, I.G.; Stark, T.D.; Strack, G.D.

    2005-01-01

    An extensively instrumented compacted earthen liner was constructed at the Illinois State Geological Survey facility in Champaign, III. in 1987. A pond of water 0.31 m deep was maintained on top of the 7.3 m ?? 14.6 m ?? 0.9 m thick liner for 14 years. One of the goals of the project was to evaluate the long-term performance of a compacted earthen liner by monitoring the long-term changes in water content and density. The water content of the earthen liner showed no trend with depth or time. The liner density remained essentially constant from construction through excavation in 2002. The liner did not become fully saturated. Upon excavation of the liner, the degree of saturation was 80.0??6.3% after 14 years of ponding under a hydraulic head of 0.31 m. The results imply that properly designed and constructed earthen liners may reduce the possibility of pollutants leaching from municipal solid waste containment facilities by remaining partially saturated for years and maintaining the placement density. Journal of Geotechnical and Geoenvironmental Engineering ?? ASCE.

  12. Non-polarizable force field of water based on the dielectric constant: TIP4P/ε.

    PubMed

    Fuentes-Azcatl, Raúl; Alejandre, José

    2014-02-06

    The static dielectric constant at room temperature and the temperature of maximum density are used as target properties to develop, by molecular dynamics simulations, the TIP4P/ε force field of water. The TIP4P parameters are used as a starting point. The key step, to determine simultaneously both properties, is to perform simulations at 240 K where a molecular dipole moment of minimum density is found. The minimum is shifted to larger values of μ as the distance between the oxygen atom and site M, lOM, decreases. First, the parameters that define the dipole moment are adjusted to reproduce the experimental dielectric constant and then the Lennard-Jones parameters are varied to match the temperature of maximum density. The minimum on density at 240 K allows understanding why reported TIP4P models fail to reproduce the temperature of maximum density, the dielectric constant, or both properties. The new model reproduces some of the thermodynamic and transport anomalies of water. Additionally, the dielectric constant, thermodynamics, and dynamical and structural properties at different temperatures and pressures are in excellent agreement with experimental data. The computational cost of the new model is the same as that of the TIP4P.

  13. Water movement in stony soils: The influence of stoniness on soil water content profiles

    NASA Astrophysics Data System (ADS)

    Novak, Viliam; Knava, Karol

    2010-05-01

    WATER MOVEMENT IN STONY SOILS: THE INFLUENCE OF STONINESS ON SOIL WATER CONTENT PROFILES Viliam Novák, Karol Kňava Institute of Hydrology, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3, Slovakia, e-mail: novak@uh.savba.sk Soils containing rock fragments are widespread over the world, on Europe such soil account for 30%, 60% in Mediterranean region. In comparison to fine earth soils (soil particles are less then 2 mm) stony soils contain rock fragments characterized by the low retention capacity and hydraulic conductivity. So, for stony soils -in comparison to the fine-earth soils - is typical lower hydraulic conductivity and retention capacity, which lead to the decrease decrease of infiltration rate and low water retention. So, water movement and its modeling in stony soil would differ from fine earth (usually agricultural) soil. The aim of this contribution is to demonstrate the differences in water movement in homogeneous soil (fine earth) and stony soil. The influence of different stoniness on soil water content and soil water dynamics was studied too. Windthrow at High Tatra mountains in Slovakia (November 2004) cleared nearly 12 000 ha of 80 year conifers and this event initiated complex research of windthrow impact on the ecosystem. The important part of this study was water movement in impacted area. Specific feature of the soil in this area was moraine soil consisting of fine earth, characterized as silty sand, with the relative stone content up to 0.49, increasing with depth. Associated phenomenon to the forest clearing is the decrease of rain interception and higher undercanopy precipitation. Conifers interception capacity can be three times higher than low canopy interception, and can reach up to 40% of annual precipitation in Central Europe. Stones in the soil are decreasing infiltration rate, but paradoxically increased understorey precipitation and followingly the increased cumulative infiltration led to the increase of the soil

  14. Relationship between optical extinction and liquid water content in fogs

    NASA Astrophysics Data System (ADS)

    Klein, C.; Dabas, A.

    2013-11-01

    Studies carried out in the late 1970s suggest a simple linear relationship exists in practice between the optical extinction in the thermal IR and the liquid water content (LWC) in fogs. Such a relationship opens the possibility to monitor the vertical profile of the LWC in fogs with a rather simple backscatter lidar. Little is known on how the LWC varies as a function of height and during the fog life cycle, so the new measurement technique would help understand fog physics and provide valuable data for improving the quality of fog forecasts. In the present article, the validity of the linear relationship is revisited at the light of recent observations of fog droplet size distributions measured with a combination of sensors covering a large range of droplet radii. In particular, large droplets (radius above 15 μm) are detected, which was not the case in the late 1970s. The results confirm the linear relationship still holds, at least for the mostly radiative fogs observed during the campaign. The impact of the precise value of the real and imaginary parts of the refractive index on the coefficient of the linear relationship is also studied. The usual practice considers droplets are made of pure water. This assumption is probably valid for big droplets, it may be questioned for small ones since droplets are formed from condensation nuclei of highly variable chemical composition. The study suggests the relationship is mostly sensitive to the real part of the refractive index and the sensitivity grows with the size of fog droplets. However, large fog droplets are more likely to have an index close to that of water since they are mainly composed of water.

  15. Measurements of water potential and water content in unsaturated crystalline rock

    NASA Astrophysics Data System (ADS)

    Schneebeli, Martin; Flühler, Hannes; Gimmi, Thomas; Wydler, Hannes; LäSer, Hans-Peter; Baer, Toni

    1995-08-01

    A water desaturation zone develops around a tunnel in water-saturated rock when the evaporative water loss at the rock surface is larger than the water flow from the surrounding saturated region of restricted permeability. We describe the methods with which such water desaturation processes in rock materials can be quantified. The water retention characteristic θ (ψ) of crystalline rock samples was determined with a pressure membrane apparatus. The negative water potential, identical to the capillary pressure, ψ, below the tensiometric range (ψ < -0.1 MPa) can be measured with thermocouple psychrometers (TP), and the volumetric water contents, θ, by means of time domain reflectometry (TDR). These standard methods were adapted for measuring the water status in a macroscopically unfissured granodiorite with a total porosity of approximately 0.01. The measured water retention curve of granodiorite samples from the Grimsel test site (central Switzerland) exhibits a shape which is typical for bimodal pore size distributions. The measured bimodality is probably an artifact of a large surface ratio of solid/voids. The thermocouples were installed without a metallic screen using the cavity drilled into the granodiorite as a measuring chamber. The water potentials observed in a cylindrical granodiorite monolith ranged between -0.1 and -3.0 MPa; those near the wall in a ventilated tunnel between -0.1 and -2.2 MPa. Two types of three-rod TDR probes were used, one as a depth probe inserted into the rock, the other as a surface probe using three copper stripes attached to the surface for detecting water content changes in the rock-to-air boundary. The TDR signal was smoothed with a low-pass filter, and the signal length determined based on the first derivative of the trace. Despite the low porosity of crystalline rock these standard methods are applicable to describe the unsaturated zone in solid rock and may also be used in other consolidated materials such as concrete.

  16. Collimated neutron probe for soil water content measurements

    USGS Publications Warehouse

    Klenke, J.M.; Flint, A.L.

    1991-01-01

    A collimated neutron probe was designed to enable mesurements in specific directions from the access tube. To determine the size and shape of soil volume affecting the neutron counts, experiments were conducted to evaluate: 1) the vertical distance of soil above and below the probe that influences neutron counts; 2) the horizontal distance away from the probe into the soil that influences neutron counts; 3) the angle of soil viewed by the probe from the collimator; and 4) the three-dimensional thermal-neutron density field. The vertical distance was ~0.5m, the horizontal distance was ~0.2m, and the angle of soil viewed by the probe from the collimator was ~120??. Thermal neutrons detected from distances or angles larger than these values influence the determination of relative water content by 5% or less. -from Authors

  17. Electrostatic field-exposed water in nanotube at constant axial pressure

    PubMed Central

    He, Yuchi; Sun, Gang; Koga, Kenichiro; Xu, Limei

    2014-01-01

    Water confined within nanoscale geometries under external field has many interesting properties which is very important for its application in biological processes and engineering. Using molecular dynamics simulations, we investigate the effect of external fields on polarization and structure as well as phase transformations of water confined within carbon nanotubes. We find that dipoles of water molecules tend to align along external field in nanoscale cylindrical confinement. Such alignment directly leads to the longitudinal electrostriction and cross-sectional dilation of water in nanotube. It also influences the stability of ice structures. As the electrostatic field strengthens, the confined water undergoes phase transitions from a prism structure to a helical one to a single chain as the electrostatic field strengthens. These results imply a rich phase diagram of the confined water due to the presence of external electriostatic field, which can be of importance for the industrial applications in nanopores. PMID:25318649

  18. Phase equilibria and distribution constants of metal ions in diantipyryl alkane-organic acid-hydrochloric acid-water systems

    NASA Astrophysics Data System (ADS)

    Degtev, M. I.; Popova, O. N.; Yuminova, A. A.

    2014-08-01

    The ability of antipyrine and its derivatives (diantipyryl alkanes) to form separating systems in the presence of salicylic (sulfosalicylic) acid and hydrochloric acid and water is studied. The optimum volume of the organic phase, the composition of complexes, and the mechanism for the distribution of metal ions are determined, depending on the concentrations of the main components and the salting-out agent. The complex distribution and extraction constants are calculated.

  19. Tsunami and acoustic-gravity waves in water of constant depth

    SciTech Connect

    Hendin, Gali; Stiassnie, Michael

    2013-08-15

    A study of wave radiation by a rather general bottom displacement, in a compressible ocean of otherwise constant depth, is carried out within the framework of a three-dimensional linear theory. Simple analytic expressions for the flow field, at large distance from the disturbance, are derived. Realistic numerical examples indicate that the Acoustic-Gravity waves, which significantly precede the Tsunami, are expected to leave a measurable signature on bottom-pressure records that should be considered for early detection of Tsunami.

  20. Radiocarbon Content of Intermediate Waters off West Sumatra During the Last 45,000 Years

    NASA Astrophysics Data System (ADS)

    De Pol-Holz, R.; Mohtadi, M.; Southon, J. R.

    2014-12-01

    Radiocarbon content of intermediate waters originating from the Southern Ocean is held as a likely smoking gun of the events that triggered the atmospheric CO2 rise and its radiocarbon decline during the last glacial-interglacial transition. Late Glacial depleted radiocarbon water masses have been found at intermediate depths off the coast of Baja California, the Galapagos, the Arabian Sea, but not unequivocally elsewhere. Knowing the route of the old water is therefore central for the required mechanistic linkage of Southern Ocean processes and the atmospheric response. A common approach to search for the old water reservoir is the radiocarbon difference between planktonic and benthic foraminifera or 'apparent ventilation age'. Caveats of this approach are due to the fact that it relies strongly on the knowledge of the surface water reservoir age. In this study, we present a high-resolution radiocarbon difference between surface and intermediate depth waters off west Sumatra in the attempt to elucidate a possible route of the old water from its hypothetical source in the high latitudes near Antarctica on its way to the lower latitude sites where it has been observed. Samples come from core SO189-39KL (0°47'S, 99°55'E, 517 m), a 1350 cm hemipelagic sedimentary sequence that spans the last 45,000 years. Radiocarbon determinations were made at centennial time resolution on both planktonic and benthic species. Calibration of the planktonic radiocarbon as age control points allowed us to infer the Δ14C of the intermediate waters. Our results show that throughout the LGM and the entire deglaciation, radiocarbon content of intermediate depths in the area remained with an almost constant age difference with the contemporaneous atmosphere. Unless we have grossly underestimated the local planktonic reservoir age, our results discard this area as a probable route for the spreading of the old water along its way to northern latitudes. In light of recent evidence from the

  1. Improved SPC force field of water based on the dielectric constant: SPC/ ε

    NASA Astrophysics Data System (ADS)

    Fuentes-Azcatl, Raúl; Mendoza, Noé; Alejandre, José

    2015-02-01

    In a recent work, Fuentes and Alejandre (2014) found that for TIP4P models there is a dipole moment of minimum density at 240 K and that the Lennard-Jones parameters can be adjusted to match the experimental dielectric constant at 300 K and the temperature of maximum density, respectively. The same procedure is used in this work to re-parameterize the simple point charge (SPC) model keeping the original geometry. The new model fails to reproduce the experimental self-diffusion coefficient and shear viscosity but improves the results at different temperatures and pressures of dielectric constant, isothermal compressibility, thermal expansion coefficient, surface tension, coexisting densities at the liquid-vapor interface, equation of state of ice Ih and equation of state of liquids at high pressures. A second model that reproduces the dielectric constant, self-diffusion coefficient and shear viscosity is proposed but the temperature of maximum density is 250 K, compared with the experimental value of 277 K. Both models improve the SPC/E results for almost all properties. The TIP3P model was also analyzed but the liquid density at 240 K always increases and a minimum in the dipole moment was not found. It is not possible to adjust for that model the charge distribution and short range interaction parameters to reproduce at the same time the target properties.

  2. THE OSMOTICALLY FUNCTIONAL WATER CONTENT OF THE HUMAN ERYTHROCYTE.

    PubMed

    LEFEVRE, P G

    1964-01-01

    Experiments were directed toward estimation of the magnitude of error incurred by the presumption of idealized osmometric behavior in the author's recent studies of monosaccharide transport through the human erythrocyte membrane. Thick suspensions of washed cells in isotonic buffered balanced salt medium were mixed in fixed proportions with varying dilutions of a concentrate of either (a) the mixed chlorides of the medium, or (b) glucose in the isotonic medium, and the resultant freezing point and hematocrit values determined. The form of the responses in the tonicity and the cell volume, as functions of the variable dilution of sugar or salts, conformed consistently with relations derived from the classical van't Hoff-Boyle-Mariotte pressure-volume relation. However, the effective cell water contents appeared substantially less than the weight lost in conventional drying, and varied somewhat according to the index used: expressed as grams of H(2)O per milliliter of cells at isotonic volume, the cell water implied by the hematocrit behavior was 0.614 +/- 0.015 (SD); by the salt tonicity response, 0.565 +/- 0.027; by the immediate glucose tonicity response, 0.562 +/- 0.044; and by the equilibrium glucose tonicities, 0.589 +/- 0.043. Olmstead's reports of gross deviation from the van't Hoff relation, in the rabbit red cell's responses to tonicity displacement, are attributed primarily to a systematic aberration in his method of data analysis, the observations themselves agreeing substantially with the present findings.

  3. A Review on Temporal Stability of Soil Water Contents

    NASA Astrophysics Data System (ADS)

    Vanderlinden, Karl; Vereecken, Harry; Hardelauf, Horst; Herbst, Michael; Martínez, Gonzalo; Cosh, Michael H.; Pachepsky, Yakov A.

    2013-04-01

    Temporal stability of soil water content (TS SWC) has been observed across a wide range of soil types, landscapes, climates and scales. A better understanding of TS SWC controls and their interactions needs to be developed. The objective of this work is to develop a comprehensive inventory of published data on TC SWC and to determine knowledge gaps. Mean relative difference (MRD) values and associated standard deviations (SDRD) were digitized from 157 graphs in 37 publications and analyzed. The MRD followed generally a Gaussian distribution with the determination coefficient R2 > 0.84. The standard deviation of MRD (SDMRD) showed a trend of increase with scale. No relationship between SDMRD and R2 was observed. The smallest R2 values were mostly found for negatively skewed and platykurtic MRD distributions. An analysis of seven measurement-, terrain-, and climate-related TS SWC controls suggested strong interactions and showed that combined effects are typically observed. Many of the existing datasets on TS WCS are mostly byproducts of soil water dynamics studies in agronomic or environmental projects. Future research should include more focused TS SWC studies tailored to understand interactions of controls, underlying mechanisms, and efficiency of applications.

  4. Correlation among Cirrus Ice Content, Water Vapor and Temperature in the TTL as Observed by CALIPSO and Aura-MLS

    NASA Technical Reports Server (NTRS)

    Flury, T.; Wu, D. L.; Read, W. G.

    2012-01-01

    Water vapor in the tropical tropopause layer (TTL) has a local radiative cooling effect. As a source for ice in cirrus clouds, however, it can also indirectly produce infrared heating. Using NASA A-Train satellite measurements of CALIPSO and Aura/MLS we calculated the correlation of water vapor, ice water content and temperature in the TTL. We find that temperature strongly controls water vapor (correlation r =0.94) and cirrus clouds at 100 hPa (r = -0.91). Moreover we observe that the cirrus seasonal cycle is highly (r =-0.9) anticorrelated with the water vapor variation in the TTL, showing higher cloud occurrence during December-January-February. We further investigate the anticorrelation on a regional scale and find that the strong anticorrelation occurs generally in the ITCZ (Intertropical Convergence Zone). The seasonal cycle of the cirrus ice water content is also highly anticorrelated to water vapor (r = -0.91) and our results support the hypothesis that the total water at 100 hPa is roughly constant. Temperature acts as a main regulator for balancing the partition between water vapor and cirrus clouds. Thus, to a large extent, the depleting water vapor in the TTL during DJF is a manifestation of cirrus formation.

  5. Multiscale Bayesian neural networks for soil water content estimation

    NASA Astrophysics Data System (ADS)

    Jana, Raghavendra B.; Mohanty, Binayak P.; Springer, Everett P.

    2008-08-01

    Artificial neural networks (ANN) have been used for some time now to estimate soil hydraulic parameters from other available or more easily measurable soil properties. However, most such uses of ANNs as pedotransfer functions (PTFs) have been at matching spatial scales (1:1) of inputs and outputs. This approach assumes that the outputs are only required at the same scale as the input data. Unfortunately, this is rarely true. Different hydrologic, hydroclimatic, and contaminant transport models require soil hydraulic parameter data at different spatial scales, depending upon their grid sizes. While conventional (deterministic) ANNs have been traditionally used in these studies, the use of Bayesian training of ANNs is a more recent development. In this paper, we develop a Bayesian framework to derive soil water retention function including its uncertainty at the point or local scale using PTFs trained with coarser-scale Soil Survey Geographic (SSURGO)-based soil data. The approach includes an ANN trained with Bayesian techniques as a PTF tool with training and validation data collected across spatial extents (scales) in two different regions in the United States. The two study areas include the Las Cruces Trench site in the Rio Grande basin of New Mexico, and the Southern Great Plains 1997 (SGP97) hydrology experimental region in Oklahoma. Each region-specific Bayesian ANN is trained using soil texture and bulk density data from the SSURGO database (scale 1:24,000), and predictions of the soil water contents at different pressure heads with point scale data (1:1) inputs are made. The resulting outputs are corrected for bias using both linear and nonlinear correction techniques. The results show good agreement between the soil water content values measured at the point scale and those predicted by the Bayesian ANN-based PTFs for both the study sites. Overall, Bayesian ANNs coupled with nonlinear bias correction are found to be very suitable tools for deriving soil

  6. A global sensitivity analysis of crop virtual water content

    NASA Astrophysics Data System (ADS)

    Tamea, S.; Tuninetti, M.; D'Odorico, P.; Laio, F.; Ridolfi, L.

    2015-12-01

    The concepts of virtual water and water footprint are becoming widely used in the scientific literature and they are proving their usefulness in a number of multidisciplinary contexts. With such growing interest a measure of data reliability (and uncertainty) is becoming pressing but, as of today, assessments of data sensitivity to model parameters, performed at the global scale, are not known. This contribution aims at filling this gap. Starting point of this study is the evaluation of the green and blue virtual water content (VWC) of four staple crops (i.e. wheat, rice, maize, and soybean) at a global high resolution scale. In each grid cell, the crop VWC is given by the ratio between the total crop evapotranspiration over the growing season and the crop actual yield, where evapotranspiration is determined with a detailed daily soil water balance and actual yield is estimated using country-based data, adjusted to account for spatial variability. The model provides estimates of the VWC at a 5x5 arc minutes and it improves on previous works by using the newest available data and including multi-cropping practices in the evaluation. The model is then used as the basis for a sensitivity analysis, in order to evaluate the role of model parameters in affecting the VWC and to understand how uncertainties in input data propagate and impact the VWC accounting. In each cell, small changes are exerted to one parameter at a time, and a sensitivity index is determined as the ratio between the relative change of VWC and the relative change of the input parameter with respect to its reference value. At the global scale, VWC is found to be most sensitive to the planting date, with a positive (direct) or negative (inverse) sensitivity index depending on the typical season of crop planting date. VWC is also markedly dependent on the length of the growing period, with an increase in length always producing an increase of VWC, but with higher spatial variability for rice than for

  7. Humidity-conditioned gravimetric method to measure the water content of hydrogel contact lens materials.

    PubMed

    Galas, S L; Enns, J B

    1993-07-01

    A method to determine the humidity-conditioned gravimetric water content of hydrogel contact lens materials has been developed, in which errors due to blotting have been eliminated by conditioning the lens in a series of relative humidity (RH) environments before measuring the water content gravimetrically, and then extrapolating the water content to 100% RH. This method has been used to determine the water contents of representative materials from each of the four FDA lens groups, which were compared with their labeled values, as well as with values obtained from refractive index measurements. The deviation of the water content of soft contact lenses as measured by refractive index from that obtained gravimetrically increased as the water content decreased. The humidity-conditioned gravimetric method to determine water content of hydrophilic contact lenses is being proposed as an International Organization for Standardization (ISO) standard, as an improvement over the gravimetric and refractive index methods.

  8. Understanding the bias between moisture content by oven drying and water content by Karl Fischer titration at moisture equilibrium

    USDA-ARS?s Scientific Manuscript database

    Multiple causes of the difference between equilibrium moisture and water content have been found. The errors or biases were traced to the oven drying procedure to determine moisture content. The present paper explains the nature of the biases in oven drying and how it is possible to suppress one ...

  9. Terahertz-dependent evaluation of water content in high-water-cut crude oil using additive-manufactured samplers

    NASA Astrophysics Data System (ADS)

    Guan, LiMei; Zhan, HongLei; Miao, XinYang; Zhu, Jing; Zhao, Kun

    2017-04-01

    The evaluation of water content in crude oil is of significance to petroleum exploration and transportation. Terahertz (THz) waves are sensitive to fluctuations in the dipole moment of water. However, due to the strong absorption of water in the THz range, it is difficult for the THz spectrum to determine high water content with the common sampler. In this research, micron-grade samplers for THz detection were designed and manufactured using additive manufacturing (AM) technology. Oil-water mixtures with water content from 1.8% to 90.6% were measured with the THz-TDS system using sample cells. In addition, a detailed analysis was performed of the relationships among THz parameters such as signal peak, time delay, and refractive index as well as absorption coefficient and high water content (>60%). Results suggest that the combination of THz spectroscopy and AM technique is effective for water content evaluation in crude oil and can be further applied in the petroleum industry.

  10. Terahertz-dependent evaluation of water content in high-water-cut crude oil using additive-manufactured samplers

    NASA Astrophysics Data System (ADS)

    Guan, LiMei; Zhan, HongLei; Miao, XinYang; Zhu, Jing; Zhao, Kun

    2017-04-01

    The evaluation of water content in crude oil is of significance to petroleum exploration and transportation. Terahertz (THz) waves are sensitive to fluctuations in the dipole moment of water. However, due to the strong absorption of water in the THz range, it is difficult for the THz spectrum to determine high water content with the common sampler. In this research, micron-grade samplers for THz detection were designed and manufactured using additive manufacturing (AM) technology. Oil-water mixtures with water content from 1.8% to 90.6% were measured with the THz-TDS system using sample cells. In addition, a detailed analysis was performed of the relationships among THz parameters such as signal peak, time delay, and refractive index as well as absorption coefficient and high water content (>60%). Results suggest that the combination of THz spectroscopy and AM technique is effective for water content evaluation in crude oil and can be further applied in the petroleum industry.

  11. An improved sensor for precision detection of in situ stem water content using a frequency domain fringing capacitor.

    PubMed

    Zhou, Haiyang; Sun, Yurui; Tyree, Melvin T; Sheng, Wenyi; Cheng, Qiang; Xue, Xuzhang; Schumann, Henrik; Schulze Lammers, Peter

    2015-04-01

    One role of stems is that of water storage. The water content of stems increases and decreases as xylem water potential increases and decreases, respectively. Hence, a nondestructive method to measure stem water content (StWC) = (volume of water) : (volume of stem), could be useful in monitoring the drought stress status of plants. We introduce a frequency domain inner fringing capacitor-sensor for measuring StWC which operates at 100 MHz frequency. The capacitor-sensor consists of two wave guides (5-mm-wide braided metal) that snugly fit around the surface of a stem with a spacing of 4-5 mm between guides. Laboratory measurements on analog stems reveals that the DC signal output responds linearly to the relative dielectric constant of the analog stem, is most sensitive to water content between the waveguides to a depth of c. 3 mm from the stem surface, and calibrations based on the gravimetric water loss of excised stems of plants revealed a resolution in StWC of < ± 0.001 v/ v. The sensor performed very well on whole plants with a 100-fold increased resolution compared with previous frequency domain and time domain reflectometry methods and, hence, may be very useful for future research requiring nondestructive measurements of whole plants. © European Union 2014. New Phytologist © 2014 New Phytologist Trust.

  12. Physicochemical properties of polycyclic aromatic hydrocarbons: Aqueous solubilities, n-octanol/water partition coefficients, and Henry`s law constants

    SciTech Connect

    Maagd, P.G.J. de; Opperhuizen, A.; Sijm, D.T.H.M.; Hulscher, D.T.E.M. ten; Heuvel, H. van den

    1998-02-01

    Aqueous solubilities, n-octanol/water partition coefficients (K{sub ow}S), and Henry`s law constants were determined for a range of polycyclic aromatic hydrocarbons (PAHs) using a generator-column, slow-stirring, and gas-purge method, respectively. The currently obtained data were compared to available literature data. For seven of the PAHs no K{sub ow}S previously were determined with the slow-stirring method. For four of the PAHs the present study reports the first experimental Henry`s law constants. Relationships between subcooled liquid solubilities, K{sub ow}S, and Henry`s law constants as a function of molar volume are discussed. A consistent data set was obtained, for which an excellent correlation was found between subcooled liquid solubility and molar volume. A linear fit did not accurately describe the relationship between log K{sub ow} and molar volume. This is probably due to a decreasing solubility in n-octanol with increasing molar volume. Finally, a high correlation was found between Henry`s law constant and molar volume. The presently obtained dataset can be used to predict the fate and behavior of unsubstituted homocyclic PAHs.

  13. Test of prototype liquid-water-content meter for aircraft use

    NASA Technical Reports Server (NTRS)

    Gerber, Hermann E.

    1993-01-01

    This report describes the effort undertaken to meet the objectives of National Science Foundation Grant ATM-9207345 titled 'Test of Prototype Liquid-Water-Content Meter for Aircraft Use.' Three activities were proposed for testing the new aircraft instrument, PVM-100A: (1) Calibrate the PVM-100A in a facility where the liquid-water-content (LWC) channel, and the integrated surface area channel (PSA) could be compared to standard means for LWC and PSA measurements. Scaling constant for the channels were to be determined in this facility. The fog/wind tunnel at ECN, Petten, The Netherlands was judged the most suitable facility for this effort. (2) Expose the PVM-100A to high wind speeds similar to those expected on research aircraft, and test the anti-icing heaters on the PVM-100A under typical icing conditions expected in atmospheric clouds. The high-speed icing tunnel at NRC, Ottawa, Canada was to be utilized. (3) Operate the PVM-100A on an aircraft during cloud penetrations to determine its stability and practicality for such measurements. The C-131A aircraft of the University of Washington was the aircraft of opportunity for these-tests, which were to be conducted during the 4-week Atlantic Stratocumulus Transition Experiment (ASTEX) in June of 1992.

  14. Constant temperature molecular dynamics of a protein in water by high-order decomposition of the Liouville operator

    NASA Astrophysics Data System (ADS)

    Ishida, Hisashi; Kidera, Akinori

    1998-08-01

    Among algorithms that are used to solve the equations of motion, the symplectic integrator (SI) has the advantage of conserving the phase space volume and ensuring a stable simulation. However, incorporating the explicit formula of the SI in a molecular simulation is feasible only for the systems whose Hamiltonian is described by K(p)+V(q), where the kinetic energy K and the potential energy V depend only on momenta p and coordinates q, respectively. Due to this limitation, explicit SI integrators cannot directly be applied to the Nosé-Hoover equations of motion for the constant temperature molecular dynamics (MD) simulation. In this article, by applying the formula of the decomposition of the exponential Liouville operator to the Nosé-Hoover equations, we have obtained a series of integrators for the constant temperature simulation which have the correct form of the Jacobian of the Nosé-Hoover equations. The systems examined here are liquid water and a protein in water. From the results of the constant temperature simulations, where several variations of the integrators were employed, we show that a combination of the Suzuki's second order formula and the fourth order symplectic integrator of Calvo and Sanz-Serna generates a trajectory of much higher accuracy than the nonsymplectic Gear predictor-corrector method for a given amount of CPU time.

  15. On the interpolation of volumetric water content in research catchments

    NASA Astrophysics Data System (ADS)

    Dlamini, Phesheya; Chaplot, Vincent

    Digital Soil Mapping (DSM) is widely used in the environmental sciences because of its accuracy and efficiency in producing soil maps compared to the traditional soil mapping. Numerous studies have investigated how the sampling density and the interpolation process of data points affect the prediction quality. While, the interpolation process is straight forward for primary attributes such as soil gravimetric water content (θg) and soil bulk density (ρb), the DSM of volumetric water content (θv), the product of θg by ρb, may either involve direct interpolations of θv (approach 1) or independent interpolation of ρb and θg data points and subsequent multiplication of ρb and θg maps (approach 2). The main objective of this study was to compare the accuracy of these two mapping approaches for θv. A 23 ha grassland catchment in KwaZulu-Natal, South Africa was selected for this study. A total of 317 data points were randomly selected and sampled during the dry season in the topsoil (0-0.05 m) for θg by ρb estimation. Data points were interpolated following approaches 1 and 2, and using inverse distance weighting with 3 or 12 neighboring points (IDW3; IDW12), regular spline with tension (RST) and ordinary kriging (OK). Based on an independent validation set of 70 data points, OK was the best interpolator for ρb (mean absolute error, MAE of 0.081 g cm-3), while θg was best estimated using IDW12 (MAE = 1.697%) and θv by IDW3 (MAE = 1.814%). It was found that approach 1 underestimated θv. Approach 2 tended to overestimate θv, but reduced the prediction bias by an average of 37% and only improved the prediction accuracy by 1.3% compared to approach 1. Such a great benefit of approach 2 (i.e., the subsequent multiplication of interpolated maps of primary variables) was unexpected considering that a higher sampling density (∼14 data point ha-1 in the present study) tends to minimize the differences between interpolations techniques and approaches. In the

  16. Modeling soil water content for vegetation modeling improvement

    NASA Astrophysics Data System (ADS)

    Cianfrani, Carmen; Buri, Aline; Zingg, Barbara; Vittoz, Pascal; Verrecchia, Eric; Guisan, Antoine

    2016-04-01

    Soil water content (SWC) is known to be important for plants as it affects the physiological processes regulating plant growth. Therefore, SWC controls plant distribution over the Earth surface, ranging from deserts and grassland to rain forests. Unfortunately, only a few data on SWC are available as its measurement is very time consuming and costly and needs specific laboratory tools. The scarcity of SWC measurements in geographic space makes it difficult to model and spatially project SWC over larger areas. In particular, it prevents its inclusion in plant species distribution model (SDMs) as predictor. The aims of this study were, first, to test a new methodology allowing problems of the scarcity of SWC measurements to be overpassed and second, to model and spatially project SWC in order to improve plant SDMs with the inclusion of SWC parameter. The study was developed in four steps. First, SWC was modeled by measuring it at 10 different pressures (expressed in pF and ranging from pF=0 to pF=4.2). The different pF represent different degrees of soil water availability for plants. An ensemble of bivariate models was built to overpass the problem of having only a few SWC measurements (n = 24) but several predictors to include in the model. Soil texture (clay, silt, sand), organic matter (OM), topographic variables (elevation, aspect, convexity), climatic variables (precipitation) and hydrological variables (river distance, NDWI) were used as predictors. Weighted ensemble models were built using only bivariate models with adjusted-R2 > 0.5 for each SWC at different pF. The second step consisted in running plant SDMs including modeled SWC jointly with the conventional topo-climatic variable used for plant SDMs. Third, SDMs were only run using the conventional topo-climatic variables. Finally, comparing the models obtained in the second and third steps allowed assessing the additional predictive power of SWC in plant SDMs. SWC ensemble models remained very good, with

  17. Impact of diurnal variation in vegetation water content on radar backscatter of maize during water stress

    NASA Astrophysics Data System (ADS)

    van Emmerik, Tim; Steele-Dunne, Susan; Judge, Jasmeet; van de Giesen, Nick

    2014-05-01

    Microwave emission and backscatter of vegetated surfaces are influenced by vegetation water content (VWC), which varies in response to availability of soil moisture in the root zone. Understanding the influence of diurnal VWC dynamics on radar backscatter will improve soil moisture retrievals using microwave remote sensing, and will provide insight into the potential use for radar to directly monitor vegetation water status. The goal of this research is to investigate the effect of diurnal variation in VWC of an agricultural canopy on backscatter for different radar configurations. Water stress was induced in a corn (Zea mays) canopy near Citra, Florida, between September 1 and October 20, 2013. Diurnal destructive samples from the canopy were collected to determine leaf, stalk and total VWC. Water stress was quantified by calculating the evaporation deficit and measuring the soil water tension. The water-cloud model was used to model the influence of VWC and soil moisture variations on backscatter for a range of frequencies, polarizations and incidence angles. Furthermore, radar backscatter time series was simulated to show the effect of water stress on the diurnal variation in backscatter due to VWC. Results of this study show the very significant effects that VWC dynamics have on radar backscatter. We also highlight the potential for vegetation and soil water status monitoring using microwave remote sensing.

  18. The Osmotically Functional Water Content of the Human Erythrocyte

    PubMed Central

    LeFevre, Paul G.

    1964-01-01

    Experiments were directed toward estimation of the magnitude of error incurred by the presumption of idealized osmometric behavior in the author's recent studies of monosaccharide transport through the human erythrocyte membrane. Thick suspensions of washed cells in isotonic buffered balanced salt medium were mixed in fixed proportions with varying dilutions of a concentrate of either (a) the mixed chlorides of the medium, or (b) glucose in the isotonic medium, and the resultant freezing point and hematocrit values determined. The form of the responses in the tonicity and the cell volume, as functions of the variable dilution of sugar or salts, conformed consistently with relations derived from the classical van't Hoff-Boyle-Mariotte pressure-volume relation. However, the effective cell water contents appeared substantially less than the weight lost in conventional drying, and varied somewhat according to the index used: expressed as grams of H2O per milliliter of cells at isotonic volume, the cell water implied by the hematocrit behavior was 0.614 ± 0.015 (SD); by the salt tonicity response, 0.565 ± 0.027; by the immediate glucose tonicity response, 0.562 ± 0.044; and by the equilibrium glucose tonicities, 0.589 ± 0.043. Olmstead's reports of gross deviation from the van't Hoff relation, in the rabbit red cell's responses to tonicity displacement, are attributed primarily to a systematic aberration in his method of data analysis, the observations themselves agreeing substantially with the present findings. PMID:14100971

  19. Molecular theory on dielectric constant at interfaces: a molecular dynamics study of the water/vapor interface.

    PubMed

    Shiratori, Kazuya; Morita, Akihiro

    2011-06-21

    Though the local dielectric constant at interfaces is an important phenomenological parameter in the analysis of surface spectroscopy, its microscopic definition has been uncertain. Here, we present a full molecular theory on the local field at interfaces with the help of molecular dynamics simulation, and thereby provide microscopic basis for the local dielectric constant so as to be consistent to the phenomenological three-layer model of interface systems. To demonstrate its performance, we applied the theory to the water/vapor interface, and obtained the local field properties near the interface where the simple dielectric model breaks down. Some computational issues pertinent to Ewald calculations of the dielectric properties are also discussed. © 2011 American Institute of Physics

  20. Estimation water vapor content using the mixing ratio method and validated with the ANFIS PWV model

    NASA Astrophysics Data System (ADS)

    Suparta, W.; Alhasa, K. M.; Singh, M. S. J.

    2017-05-01

    This study reported the comparison between water vapor content, the surface meteorological data (pressure, temperature, and relative humidity), and precipitable water vapor (PWV) produced by PWV from adaptive neuro fuzzy inference system (ANFIS) for areas in the Universiti Kebangsaan Malaysia Bangi (UKMB) station. The water vapor content value was estimated with mixing ratio method and the surface meteorological data as the parameter inputs. The accuracy of water vapor content was validated with PWV from ANFIS PWV model for the period of 20-23 December 2016. The result showed that the water vapor content has a similar trend with the PWV which produced by ANFIS PWV model (r = 0.975 at the 99% confidence level). This indicates that the water vapor content that obtained with mixing ratio agreed very well with the ANFIS PWV model. In addition, this study also found, the pattern of water vapor content and PWV have more influenced by the relative humidity.

  1. [Spectrum Variance Analysis of Tree Leaves Under the Condition of Different Leaf water Content].

    PubMed

    Wu, Jian; Chen, Tai-sheng; Pan, Li-xin

    2015-07-01

    Leaf water content is an important factor affecting tree spectral characteristics. So Exploring the leaf spectral characteristics change rule of the same tree under the condition of different leaf water content and the spectral differences of different tree leaves under the condition of the same leaf water content are not only the keys of hyperspectral vegetation remote sensing information identification but also the theoretical support of research on vegetation spectrum change as the differences in leaf water content. The spectrometer was used to observe six species of tree leaves, and the reflectivity and first order differential spectrum of different leaf water content were obtained. Then, the spectral characteristics of each tree species leaves under the condition of different leaf water content were analyzed, and the spectral differences of different tree species leaves under the condition of the same leaf water content were compared to explore possible bands of the leaf water content identification by hyperspectral remote sensing. Results show that the spectra of each tree leaf have changed a lot with the change of the leaf water content, but the change laws are different. Leaf spectral of different tree species has lager differences in some wavelength range under the condition of same leaf water content, and it provides some possibility for high precision identification of tree species.

  2. ROBUST hot wire probe efficiency for total water content measurements in glaciated conditions

    NASA Astrophysics Data System (ADS)

    Leroy, Delphine; Lilie, Lyle; Weber, Marc; Schwarzenboeck, Alfons; Strapp, J. Walter

    2017-04-01

    During the two High Altitude Ice Crystals (HAIC, Dezitter et al. 2013)/High Ice Water Content (HIWC, Strapp et al., 2016a) international flight campaigns that investigated deep convection in the tropics, the French Falcon 20 research aircraft was equipped with two different devices measuring the Total Water Content (TWC): - the IKP-2 (Isokinetic Probe, Davison et al. 2008, 2016), - and the hot wire ROBUST probe (Strapp et al. 2008; Grandin et al. 2014). The IKP-2 probe is an evaporator that has been specifically designed to measure high ice water content (Strapp et al. 2016b) with a collection efficiency near unity. It has undergone extensive performance assessment in liquid and glaciated conditions in several wind tunnels. The Robust probe was initially developed by Science Engineering Associates to estimate high ice water content in a high speed wind tunnel, in harsh conditions where other hot-wires had been observed to suffer failures. It was known at the outset that, like other hot-wire TWC probes, it would measure only a quasi-constant fraction of the true ice water content. Early wind tunnel and flight experience with the ROBUST probe revealed that this fraction was the order of 40% for ice crystals. During the HAIC/HIWC campaigns (Leroy et al. 2016, 2017), supercooled liquid water conditions were documented according to a detailed analysis of a Rosemount Ice detector (RICE) and a Cloud Droplet Probe (CDP) measurements, and were found to be rare. Thus, the HAIC/HIWC dataset represents a unique opportunity to study in more detail the ROBUST efficiency in glaciated conditions, using the IKP-2 values as a comparative reference. Comparison of IKP-2 and ROBUST measurements will show that the ROBUST behavior differs between low (below 1.5 g/m3) and high (above 2 g/m3) ice content conditions and is also sensitive to temperature. The sensitivity of the ROBUST collection efficiency to ice particles size could also be explored as optical imaging probes were part of the

  3. APPROXIMATION OF BIODEGRADATION RATE CONSTANTS FOR MONOAROMATIC HYDROCARBONS (BTEX) IN GROUND WATER

    EPA Science Inventory

    Two methods were used to approximate site-specific biodegradation rates of monoaromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylenes [BTEX]) dissolved in ground water. Both use data from monitoring wells and the hydrologic properties of the quifer to estimate a biode...

  4. APPROXIMATION OF BIODEGRADATION RATE CONSTANTS FOR MONOAROMATIC HYDROCARBONS (BTEX) IN GROUND WATER

    EPA Science Inventory

    Two methods were used to approximate site-specific biodegradation rates of monoaromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylenes [BTEX]) dissolved in ground water. Both use data from monitoring wells and the hydrologic properties of the quifer to estimate a biode...

  5. Water dimer equilibrium constant calculation: a quantum formulation including metastable states.

    PubMed

    Leforestier, Claude

    2014-02-21

    We present a full quantum evaluation of the water second virial coefficient B(T) based on the Takahashi-Imada second order approximation. As the associated trace T r[e(-βH(AB)) - e(-βH(0)(AB))] is performed in the coordinate representation, it does also include contribution from the whole continuum, i.e., resonances and collision pairs of monomers. This approach is compared to a Path Integral Monte Carlo evaluation of this coefficient by Schenter [J. Chem. Phys. 117, 6573 (2002)] for the TIP4P potential and shown to give extremely close results in the low temperature range (250-450 K) reported. Using a recent ab initio flexible potential for the water dimer, this new formulation leads to very good agreement with experimental values over the whole range of temperatures available. The virial coefficient is then used in the well known relation Kp(T) = -(B(T) - bM)/RT where the excluded volume bM is assimilated to the second virial coefficient of pure water monomer vapor and approximated from the inner repulsive part of the interaction potential. This definition, which renders bM temperature dependent, allows us to retrieve the 38 cm(3) mol(-1) value commonly used, at room temperature. The resulting values for Kp(T) are in agreement with available experimental data obtained from infrared absorption spectra of water vapor.

  6. Estimating Canopy Water Content of Chaparral Shrubs Using Optical Methods

    NASA Technical Reports Server (NTRS)

    Ustin, Susan L.; Scheer, George; Castaneda, Claudia M.; Jacquemoud, Stephane; Roberts, Dar; Green, Robert O.

    1996-01-01

    California chaparral ecosystems are exceptionally fire adapted and typically are subject to wildfire at decadal to century frequencies. The hot dry Mediterranean climate summers and the chaparral communities of the Santa Monica Mountains make wildfire one of the most serious economic and life-threatening natural disasters faced by the region. Additionally, the steep fire-burned hillsides are subject to erosion, slumpage, and mud slides during the winter rains. The Santa Monica Mountain Zone (SMMZ) is a 104,000 ha eastwest trending range with 607 m of vertical relief and located in the center of the greater Los Angeles region. A series of fires in the fall of 1993 burned from Simi Valley to Santa Monica within a few hours. Developing techniques to monitor fire hazard and predict the spread of fire is of major concern to the region. One key factor in the susceptibility to fire is the water content of the vegetation canopy. The development of imaging spectrometry and remote sensing techniques may constitute a tool to provide this information.

  7. Disinfection associated spoilage of high water content ionic matrix hydrogels.

    PubMed

    Sack, R A; Harvey, H; Nunes, I

    1989-01-01

    Chemical analysis was carried out on clinically obtained hazy white hydrogel lenses that had been exposed to hydrogen peroxide disinfection. Analysis revealed that hazing was a surface phenomenon limited to high water content ionic matrix hydrogels (type IV), the type associated with the deposition of large amounts of lysozyme. We subjected unworn lenses to cycling studies involving doping in a variable artificial tear solution followed by exposure to disinfectant; this allowed us to duplicate the clinical situation and to derive a mechanism for this phenomenon. Hazing proved independent of the presence of hydrogen peroxide but dependent on the interaction of lens-bound lysozyme and stannate anion, the latter derived from sodium stannate present in the disinfectant as a stabilizing agent. Hazing is restricted to the type IV hydrogels because only these polymers have a sufficient number of anionic binding sites and are of sufficient porosity to allow the penetration and binding of a thick layer of lysozyme. Lysozyme is essential to hazing. No other tear protein is small enough to penetrate the hydrogel matrix or basic enough to have a marked affinity for the lens and to provide binding sites for stannate anion. These findings highlight the unique vulnerability of the type IV hydrogel to interaction with trace or transient ionic constituents in tears and lens care solutions.

  8. Estimating Canopy Water Content of Chaparral Shrubs Using Optical Methods

    NASA Technical Reports Server (NTRS)

    Ustin, Susan L.; Scheer, George; Castaneda, Claudia M.; Jacquemoud, Stephane; Roberts, Dar; Green, Robert O.

    1996-01-01

    California chaparral ecosystems are exceptionally fire adapted and typically are subject to wildfire at decadal to century frequencies. The hot dry Mediterranean climate summers and the chaparral communities of the Santa Monica Mountains make wildfire one of the most serious economic and life-threatening natural disasters faced by the region. Additionally, the steep fire-burned hillsides are subject to erosion, slumpage, and mud slides during the winter rains. The Santa Monica Mountain Zone (SMMZ) is a 104,000 ha eastwest trending range with 607 m of vertical relief and located in the center of the greater Los Angeles region. A series of fires in the fall of 1993 burned from Simi Valley to Santa Monica within a few hours. Developing techniques to monitor fire hazard and predict the spread of fire is of major concern to the region. One key factor in the susceptibility to fire is the water content of the vegetation canopy. The development of imaging spectrometry and remote sensing techniques may constitute a tool to provide this information.

  9. Performance of wave function and density functional methods for water hydrogen bond spin-spin coupling constants.

    PubMed

    García de la Vega, J M; Omar, S; San Fabián, J

    2017-04-01

    Spin-spin coupling constants in water monomer and dimer have been calculated using several wave function and density functional-based methods. CCSD, MCSCF, and SOPPA wave functions methods yield similar results, specially when an additive approach is used with the MCSCF. Several functionals have been used to analyze their performance with the Jacob's ladder and a set of functionals with different HF exchange were tested. Functionals with large HF exchange appropriately predict (1) J O H , (2) J H H and (2h) J O O couplings, while (1h) J O H is better calculated with functionals that include a reduced fraction of HF exchange. Accurate functionals for (1) J O H and (2) J H H have been tested in a tetramer water model. The hydrogen bond effects on these intramolecular couplings are additive when they are calculated by SOPPA(CCSD) wave function and DFT methods. Graphical Abstract Evaluation of the additive effect of the hydrogen bond on spin-spin coupling constants of water using WF and DFT methods.

  10. Temperature dependence of the infinite dilution activity coefficient and Henry's law constant of polycyclic aromatic hydrocarbons in water.

    PubMed

    Reza, Joel; Trejo, Arturo

    2004-08-01

    The water solubility of 9,10-dihydroanthracene was experimentally determined between 278.12 and 313.17 K. Determinations were carried out by an experimental procedure developed in our laboratory, which is a modification of the dynamic coupled column liquid chromatographic technique. The uncertainty of the experimental determinations ranged from +/- 0.50% to +/- 3.10%. These data, as well as the water solubility data of other five polycyclic aromatic hydrocarbons (PAHs) previously studied, were used to calculate the temperature dependence of the infinite dilution activity coefficient of 9,10-dihydroanthracene, anthracene, pyrene, 9,10-dihydrophenanthrene, m-terphenyl, and guaiazulene in water. Molar excess enthalpies and entropies at infinite dilution, at 298.15 K, were also derived. The temperature dependence of the infinite dilution activity coefficients was used, together with literature values of the vapor pressures of supercooled liquid PAHs (p(B)(sc)), to estimate their Henry's law constants (HLC). Only HLC for anthracene, pyrene, and 9,10-dihydrophenanthrene were calculated, since no p(B)(sc) data were available in the literature for 9,10-dihydroanthracene, m-terphenyl, and guaiazulene. From the observed temperature dependence of the Henry's law constants the enthalpy and entropy of the phase change from the dissolved phase to the gas phase were also derived for anthracene, pyrene, and 9,10-dihydrophenanthrene.

  11. Formulation and make-up of simulated concentrated water, high ionic content aqueous solution

    SciTech Connect

    Gdowski, G.

    1997-04-04

    This procedure describes the formulation and make-up of Simulated Concentrated Water (SCW), a high-ionic-content water to be used for Activity E-20-50 Long-Term Corrosion Studies. This water has an ionic content which is nominally a factor of a thousand higher than that of representative waters at or near Yucca Mountain. Representative waters were chosen as J-13 well water [Harrar, 1990] and perched water at Yucca Mountain [Glassley, 1996]. J-13 well water is obtained from ground water that is in contact with the Topopah Spring tuff, which is the repository horizon rock. The perched water is located in the Topopah Spring tuff, but below the repository horizon and above the water table. A nominal thousand times higher ionic content was chosen to simulate the water that would result from the wetting of salts which have been previously deposited on a container surface.

  12. Formulation and make-up of simulate dilute water, low ionic content aqueous solution

    SciTech Connect

    Gdowski, G.

    1997-04-04

    This procedure describes the formulation and make-up of Simulated Dilute Water (SOW), a low-ionic-content water to be used for Activity E-20-50, Long-Term Corrosion Studies. This water has an ionic content which is nominally a factor of ten higher than that of representative waters at or near Yucca Mountain. Representative waters were chosen as J-13 well water [Harrar, 1990] and perched water at Yucca Mountain [Glassley, 1996]. J-13 well water is obtained from ground water that is in contact with the Topopah Spring tuff, which is the repository horizon rock. The perched water is located in the Topopah Spring tuff, but below the repository horizon and above the water table. A nominal times ten higher ionic content was chosen to simulate the effect of ionic concentrating due to elevated temperature water flowing through fractures where salts and minerals have been deposited due to evaporation and boiling.

  13. Does Water Content or Flow Rate Control Colloid Transport in Unsaturated Porous Media?

    SciTech Connect

    Thorsten Knappenberger; Markus Flury; Earl D. Mattson; James B. Harsh

    2014-03-01

    Mobile colloids can play an important role in contaminant transport in soils: many contaminants exist in colloidal form, and colloids can facilitate transport of otherwise immobile contaminants. In unsaturated soils, colloid transport is, among other factors, affected by water content and flow rate. Our objective was to determine whether water content or flow rate is more important for colloid transport. We passed negatively charged polystyrene colloids (220 nm diameter) through unsaturated sand-filled columns under steady-state flow at different water contents (effective water saturations Se ranging from 0.1 to 1.0, with Se = (? – ?r)/(?s – ?r)) and flow rates (pore water velocities v of 5 and 10 cm/min). Water content was the dominant factor in our experiments. Colloid transport decreased with decreasing water content, and below a critical water content (Se < 0.1), colloid transport was inhibited, and colloids were strained in water films. Pendular ring and water film thickness calculations indicated that colloids can move only when pendular rings are interconnected. The flow rate affected retention of colloids in the secondary energy minimum, with less colloids being trapped when the flow rate increased. These results confirm the importance of both water content and flow rate for colloid transport in unsaturated porous media and highlight the dominant role of water content.

  14. Does water content or flow rate control colloid transport in unsaturated porous media?

    PubMed

    Knappenberger, Thorsten; Flury, Markus; Mattson, Earl D; Harsh, James B

    2014-04-01

    Mobile colloids can play an important role in contaminant transport in soils: many contaminants exist in colloidal form, and colloids can facilitate transport of otherwise immobile contaminants. In unsaturated soils, colloid transport is, among other factors, affected by water content and flow rate. Our objective was to determine whether water content or flow rate is more important for colloid transport. We passed negatively charged polystyrene colloids (220 nm diameter) through unsaturated sand-filled columns under steady-state flow at different water contents (effective water saturations Se ranging from 0.1 to 1.0, with Se = (θ - θr)/(θs - θr)) and flow rates (pore water velocities v of 5 and 10 cm/min). Water content was the dominant factor in our experiments. Colloid transport decreased with decreasing water content, and below a critical water content (Se < 0.1), colloid transport was inhibited, and colloids were strained in water films. Pendular ring and water film thickness calculations indicated that colloids can move only when pendular rings are interconnected. The flow rate affected retention of colloids in the secondary energy minimum, with less colloids being trapped when the flow rate increased. These results confirm the importance of both water content and flow rate for colloid transport in unsaturated porous media and highlight the dominant role of water content.

  15. Properties of glasses with high water content. Progress report, 1 March 1980-31 January 1981

    SciTech Connect

    Tomozawa, M.; Watson, E.B.

    1981-01-01

    Glasses with high water content were prepared by a hydrothermal process and various properties were measured. The following unique features have been revealed: (1) electrical conductivity decreases substantially at first with the addition of water and then increases with the further addition of water. The phenomenon is somewhat similar to the mixed alkali effect; (2) the glass with higher water content is radiation coloration resistant; (3) with the addition of water, glasses became tougher at room temperature, suggesting the occurrence of plastic deformation.

  16. Water dimer equilibrium constant calculation: A quantum formulation including metastable states

    SciTech Connect

    Leforestier, Claude

    2014-02-21

    We present a full quantum evaluation of the water second virial coefficient B(T) based on the Takahashi-Imada second order approximation. As the associated trace Tr[e{sup −βH{sub A}{sub B}}−e{sup −βH{sub A}{sub B}{sup o}}] is performed in the coordinate representation, it does also include contribution from the whole continuum, i.e., resonances and collision pairs of monomers. This approach is compared to a Path Integral Monte Carlo evaluation of this coefficient by Schenter [J. Chem. Phys. 117, 6573 (2002)] for the TIP4P potential and shown to give extremely close results in the low temperature range (250–450 K) reported. Using a recent ab initio flexible potential for the water dimer, this new formulation leads to very good agreement with experimental values over the whole range of temperatures available. The virial coefficient is then used in the well known relation K{sub p}(T) = −(B(T) − b{sub M})/RT where the excluded volume b{sub M} is assimilated to the second virial coefficient of pure water monomer vapor and approximated from the inner repulsive part of the interaction potential. This definition, which renders b{sub M} temperature dependent, allows us to retrieve the 38 cm{sup 3} mol{sup −1} value commonly used, at room temperature. The resulting values for K{sub p}(T) are in agreement with available experimental data obtained from infrared absorption spectra of water vapor.

  17. Hydrogen bond network in the hydration layer of the water confined in nanotubes increasing the dielectric constant parallel along the nanotube axis.

    PubMed

    Qi, Wenpeng; Zhao, Hongwei

    2015-09-21

    The water confined in nanotubes has been extensively studied, because of the potential usages in drug delivery and desalination. The radial distribution of the dielectric constant parallel along the nanotube axis was obtained by molecular dynamics simulations in a carbon nanotube and a nanotube with a very small van der Waals potential. The confined water was divided into two parts, the middle part water and the hydration water. In both cases, the hydrogen bond orientation of the middle water is isotropic, while the hydrogen bonds in hydration layers are apt to parallel along the nanotube axis. Therefore, the hydration water has higher dipole correlations increasing the dielectric constant along the nanotube axis.

  18. Hydrogen bond network in the hydration layer of the water confined in nanotubes increasing the dielectric constant parallel along the nanotube axis

    NASA Astrophysics Data System (ADS)

    Qi, Wenpeng; Zhao, Hongwei

    2015-09-01

    The water confined in nanotubes has been extensively studied, because of the potential usages in drug delivery and desalination. The radial distribution of the dielectric constant parallel along the nanotube axis was obtained by molecular dynamics simulations in a carbon nanotube and a nanotube with a very small van der Waals potential. The confined water was divided into two parts, the middle part water and the hydration water. In both cases, the hydrogen bond orientation of the middle water is isotropic, while the hydrogen bonds in hydration layers are apt to parallel along the nanotube axis. Therefore, the hydration water has higher dipole correlations increasing the dielectric constant along the nanotube axis.

  19. A nonlinear Schrödinger equation for capillary-gravity water waves on finite depth with constant vorticity

    NASA Astrophysics Data System (ADS)

    Hsu, Hung-Chu; Kharif, Christian; Francius, Marc; Chen, Yang-Yih

    2015-04-01

    In this study a nonlinear Schrödinger equation governing the complex envelope of a capillary-gravity water wave train propagating on uniform vertical shear current is derived. When the vorticity and surface tension vanishes, the classical NLS equation is found. The influence of constant vorticity and surface tension on the well-known stability properties of weakly nonlinear wave packets is studied. It is demonstrated that vorticity and surface tension modifies significantly the modulational instability properties of weakly nonlinear plane waves, namely the growth rate and bandwidth. Comparison with a fully nonlinear approach is conducted, too.

  20. Remote sensing of leaf, canopy and vegetation water contents for satellite climate data records

    USDA-ARS?s Scientific Manuscript database

    Foliar water content is a dynamic quantity depending on water losses from transpiration and water uptake from the soil. Absorption of shortwave radiation by water is determined by various frequency overtones of fundamental bending and stretching molecular transitions. Leaf water potential and rela...

  1. In vivo measurement of the water content in the dermis by confocal Raman spectroscopy.

    PubMed

    Nakagawa, Noriaki; Matsumoto, Masayuki; Sakai, Shingo

    2010-05-01

    Dermal water plays an important role in the physical properties of the skin. Recently, researchers have attempted to directly measure the dermal water content in vivo using magnetic resonance imaging, near infrared spectroscopy, and Raman spectroscopy. However, these methods have limitations. Although confocal Raman spectroscopy has been developed to measure the water content in the skin, no reports have suggested that this instrument can measure the dermal water content. This report describes a method for measuring the dermal water content in vivo using confocal Raman spectroscopy. We used a confocal Raman spectrometer and adjusted the laser exposure time and depth increments according to the skin depth. Age-related changes in the dermal water content of the forearm were examined in 30 young and 30 elderly male subjects. Diurnal changes in the dermal water content of the forearm were examined in 12 elderly male subjects. Adjusting the exposure time and depth increment dramatically improved the signal-to-noise ratios of the Raman spectra. Elderly dermis had significantly higher water content than young dermis. Moreover, the dermal water content displayed a diurnal change. This study demonstrates that the dermal water content can be measured in vivo using confocal Raman spectroscopy.

  2. Coupled simulation of soil energy and water content to compare dielectric behaviour with TDR measurements in frozen soil

    NASA Astrophysics Data System (ADS)

    Muerth, Markus; Schlenz, Florian; Loew, Alexander; Mauser, Wolfram

    2010-05-01

    In the field of soil moisture monitoring both, on-site time domain reflectometry (TDR) methods and microwave remote sensing, measure the actual soil water content via the dielectric behavior of the soil-water-air mixture. Basically, the dielectric behavior is not only influenced by soil water content, but also by temperature, soil ice content, soil texture and porosity. However, many TDR and microwave techniques relate soil water content directly to soil dielectric behavior, because they lack the ability to determine the other relevant soil properties directly. The advantage of the combination of modeling and monitoring techniques for soil moisture monitoring is the ability to understand and compare spatial and temporal patterns, especially if other land surface properties influence the retrieved soil moisture signal. In this case, the hydrological land surface model PROMET (Processes of Mass, Energy and Radiation Transfer) is combined with TDR probe measurements taken at multiple sites and multiple depths during the winter 2008/2009 in south-eastern Germany. The harsh conditions, especially during January and February 2009 led to low measured liquid water contents in the upper 20 cm of the investigated soils, although the total water content remained nearly constant over time. Additionally, soil temperature and meteorological drivers were measured at nearby agrometeorological stations. Because PROMET has shown to simulate moisture content of non-frozen soils well, compared to TDR probe and remote sensing data, we investigate its ability to simulate frozen soil water content, when enhanced with an energy balance driven soil temperature module. Furthermore, a semi-empirical dielectric mixing model is implemented to directly compare the simulated soil dielectric behavior with the available TDR probe time series. It is shown that the explicit computation of the soil surface energy balance coupled with a physically based soil temperature model is able to simulate the

  3. Determining water content in activated carbon for double-layer capacitor electrodes

    NASA Astrophysics Data System (ADS)

    Egashira, Minato; Izumi, Takuma; Yoshimoto, Nobuko; Morita, Masayuki

    2016-09-01

    Karl-Fisher titration is used to estimate water contents in activated carbon and the distribution of impurity-level water in an activated carbon-solvent system. Normalization of the water content of activated carbon is attempted using vacuum drying after immersion in water was controlled. Although vacuum drying at 473 K and 24 h can remove large amounts of water, a substantial amount of water remains in the activated carbon. The water release to propylene carbonate is less than that to acetonitrile. The degradation of capacitor cell capacitance for activated carbon with some amount of water differs according to the electrolyte solvent type: acetonitrile promotes greater degradation than propylene carbonate does.

  4. Strontium Content and Variable Strontium-Chlorinity Relationship of Sargasso Sea Water.

    PubMed

    Mackenzie, F T

    1964-10-23

    Sargasso Sea water has a variable strontium-chlorinity relationship. This observation is contrary to the view that strontium in the ocean is in constant proportion to chlorinity. It is suggested that the increase in strontium concentration at 500 to 800 meters in Sargasso Sea water results from interaction between organic aggregates and the water.

  5. [Effect of water stress on content of active constituents in Erigeron breviscaps].

    PubMed

    Zhang, Ya'ni; Su, Wenhua; Zhang, Guangfei

    2009-05-01

    To study the effect of water stress on the content of scutellarin and caffeate in Erigeron breviscaps. Fv/Fm, N content, as well as the content of scutellarin and caffeate under three water grads were measured. Fv/Fm of the plant decreased significantly in 8% and 23% water treatment, that proved drought and waterlogging occurred. Under the two conditions, the contents of N were lower but the contents of active constituents were higher than those under 15% treatment. The results support the carbon-nutrient balance hypothesis and the "stress effect hypothesis" for the formation of geo-herbs.

  6. Relationships between electrical conductivity - water content, water potential and unsaturated hydraulic conductivity for three soil types

    NASA Astrophysics Data System (ADS)

    Doussan, Cl.; Ruy, S.; Cousin, I.

    2003-04-01

    In soil physics, water retention and hydraulic conductivity are key parameters for predicting water fluxes in soils. Determination of these hydrodynamic characteristics in the lab, particularly unsaturated hydraulic conductivity, is most often complicated, time consuming and error-prone. These difficulties often prohibit the examination of numerous soil samples for determining these parameters as would be necessary to get a good estimation of the field variability. In this case, an indirect and easy to measure variable, closely linked to water retention or hydraulic conductivity, would be helpful in the assessment of these parameters. Electrical conductivity (EC) is a good candidate for such a variable because, in a porous medium, its magnitude is largely determined by the number of water filled pores and their connectivity. Relationships between water content (or saturation) and EC have been established both from empirical or theoretical point of view for some time. However, relationships between EC and unsaturated hydraulic conductivity are much more scarce, as are experimental data. We present relationships between EC and water content or water potential for three soil types: a clay loam, a sandy loam and a sand. We also present experimental relationship between EC and unsaturated hydraulic conductivity for the sandy loam. The soil were cored in the field with PVC tubes 9.5 cm inner diameter × 3 cm height. Water retention was measured using sand boxes and pressure plates apparatus. Hydraulic conductivity was calculated from the Wind evaporation method and from steady state measurements for low suctions. For each suction, the EC of the bulk was calculated from complex impedance measurements at various frequencies using two circular stainless steal electrodes located above and at the bottom of the soil core. Mercury porosimetry measurements were also performed after the experiments. Water saturation reasonably follows a power-law relationship with relative EC (EC

  7. Using measured soil water contents to estimate evapotranspiration and root water uptake profiles - a comparative study

    NASA Astrophysics Data System (ADS)

    Guderle, M.; Hildebrandt, A.

    2015-01-01

    Understanding the role of plants in soil water relations, and thus ecosystem functioning, requires information about root water uptake. We evaluated four different complex water balance methods to estimate sink term patterns and evapotranspiration directly from soil moisture measurements. We tested four methods. The first two take the difference between two measurement intervals as evapotranspiration, thus neglecting vertical flow. The third uses regression on the soil water content time series and differences between day and night to account for vertical flow. The fourth accounts for vertical flow using a numerical model and iteratively solves for the sink term. None of these methods requires any a priori information of root distribution parameters or evapotranspiration, which is an advantage compared to common root water uptake models. To test the methods, a synthetic experiment with numerical simulations for a grassland ecosystem was conducted. Additionally, the time series were perturbed to simulate common sensor errors, like those due to measurement precision and inaccurate sensor calibration. We tested each method for a range of measurement frequencies and applied performance criteria to evaluate the suitability of each method. In general, we show that methods accounting for vertical flow predict evapotranspiration and the sink term distribution more accurately than the simpler approaches. Under consideration of possible measurement uncertainties, the method based on regression and differentiating between day and night cycles leads to the best and most robust estimation of sink term patterns. It is thus an alternative to more complex inverse numerical methods. This study demonstrates that highly resolved (temporally and spatially) soil water content measurements may be used to estimate the sink term profiles when the appropriate approach is used.

  8. Kinetics of the transformation of phenyl-urea herbicides during ozonation of natural waters: rate constants and model predictions.

    PubMed

    Benitez, F Javier; Real, Francisco J; Acero, Juan L; Garcia, Carolina

    2007-10-01

    Oxidation of four phenyl-urea herbicides (isoproturon, chlortoluron, diuron, and linuron) was studied by ozone at pH=2, and by a combination of O3/H2O2 at pH=9. These experiments allowed the determination of the rate constants for their reactions with ozone and OH radicals. For reactions with ozone, the following rate constants were obtained: 1.9 +/- 0.2, 16.5 +/- 0.6, 393.5 +/- 8.4, and 2191 +/- 259 M(-1) s(-1) for linuron, diuron, chlortoluron, and isoproturon, respectively. The rate constants for the reaction with OH radicals were (7.9 +/- 0.1) x 10(9) M(-1) s(-1) for isoproturon, (6.9 +/- 0.2) x 10(9) M(-1) s(-1) for chlortoluron, (6.6 +/- 0.1) x 10(5) M(-1) s(-1) for diuron, and (5.9 +/- 0.1) x 10(9) M(-1) s(-1) for linuron. Furthermore, the simultaneous ozonation of these selected herbicides in some natural water systems (a commercial mineral water, a groundwater, and surface water from a reservoir) was studied. The influence of operating conditions (initial ozone dose, nature of herbicides, and type of water systems) on herbicide removal efficiency was established, and the parameter Rct (proposed by Elovitz, M.S., von Gunten, U., 1999. Hydroxyl radical/ozone ratios during ozonation processes. I. The Rct concept. Ozone Sci. Eng. 21, 239-260) was evaluated from simultaneous measurement of ozone and OH radicals. A kinetic model was proposed for the prediction of the elimination rate of herbicides in these natural waters, and application of this model revealed that experimental results and predicted values agreed fairly well. Finally, the partial contributions of direct ozone and radical pathways were evaluated, and the results showed that reaction with OH radicals was the major pathway for the oxidative transformation of diuron and linuron, even when conventional ozonation was applied, while for chlortoluron and isoproturon, direct ozonation was the major pathway.

  9. Aqueous solubility, Henry's law constants and air/water partition coefficients of n-octane and two halogenated octanes.

    PubMed

    Sarraute, S; Delepine, H; Costa Gomes, M F; Majer, V

    2004-12-01

    New data on the aqueous solubility of n-octane, 1-chlorooctane and 1-bromooctane are reported between 1 degree C and 45 degrees C. Henry's law constants, K(H), and air/water partition coefficients, K(AW), were calculated by associating the measured solubility values to vapor pressures taken from literature. The mole fraction aqueous solubility varies between (1.13-1.60)x10(-7) for n-octane with a minimum at approximately 23 degrees C, (3.99-5.07)x10(-7) for 1-chlorooctane increasing monotonically with temperature and (1.60-3.44)x10(-7) for 1-bromooctane with a minimum near 18 degrees C. The calculated air-water partition coefficients increase with temperature and are two orders of magnitude lower for the halogenated derivatives compared to octane. The precision of the results, taken as the average absolute deviations of the aqueous solubility, the Henry's law constants, or the air/water partition coefficients, from appropriate smoothing equations as a function of temperature is of 3% for n-octane and of 2% and 4% for 1-chlorooctane and 1-bromooctane, respectively. A new apparatus based on the dynamic saturation column method was used for the solubility measurements. Test measurements with n-octane indicated the capability of measuring solubilities between 10(-6) and 10(-10) in mole fraction, with an estimated accuracy better than +/-10%. A thorough thermodynamic analysis of converting measured data to air/water partition coefficients is presented.

  10. Sensing the water content of honey from temperature-dependent electrical conductivity

    NASA Astrophysics Data System (ADS)

    Guo, Wenchuan; Liu, Yi; Zhu, Xinhua; Zhuang, Hong

    2011-08-01

    In order to predict the water content in honey, electrical conductivity was measured on blossom honey types milk-vetch, jujube and yellow-locust with the water content of 18-37% between 5 and 40 °C. The regression models of electrical conductivity were developed as functions of water content and temperature. The results showed that increases in either water content or temperature resulted in an increase in the electrical conductivity of honey with greater changes at higher water content and/or higher temperature. The linear terms of water content and temperature, a quadratic term of water content, and the interaction effect of water content and temperature had significant influence on the electrical conductivity of honey (p < 0.0001). Regardless of blossom honey type, the linear coefficient of the determination of measured and calculated electrical conductivities was 0.998 and the range error ratio was larger than 100. These results suggest that the electrical conductivity of honey might be used to develop a detector for rapidly predicting the water content in blossom honey.

  11. Effect of water content on stability of landslides triggered by earthquakes

    NASA Astrophysics Data System (ADS)

    Beyabanaki, S.; Bagtzoglou, A. C.; Anagnostou, E. N.

    2013-12-01

    Earthquake- triggered landslides are one of the most important natural hazards that often result in serious structural damage and loss of life. They are widely studied by several researchers. However, less attention has been focused on soil water content. Although the effect of water content has been widely studied for rainfall- triggered landslides [1], much less attention has been given to it for stability analysis of earthquake- triggered landslides. We developed a combined hydrology and stability model to investigate effect of soil water content on earthquake-triggered landslides. For this purpose, Bishop's method is used to do the slope stability analysis and Richard's equation is employed to model infiltration. Bishop's method is one the most widely methods used for analyzing stability of slopes [2]. Earthquake acceleration coefficient (EAC) is also considered in the model to analyze the effect of earthquake on slope stability. Also, this model is able to automatically determine geometry of the potential landslide. In this study, slopes with different initial water contents are simulated. First, the simulation is performed in the case of earthquake only with different EACs and water contents. As shown in Fig. 1, initial water content has a significant effect on factor of safety (FS). Greater initial water contents lead to less FS. This impact is more significant when EAC is small. Also, when initial water content is high, landslides can happen even with small earthquake accelerations. Moreover, in this study, effect of water content on geometry of landslides is investigated. For this purpose, different cases of landslides triggered by earthquakes only and both rainfall and earthquake for different initial water contents are simulated. The results show that water content has more significant effect on geometry of landslides triggered by rainfall than those triggered by an earthquake. Finally, effect of water content on landslides triggered by earthquakes

  12. The NOAA Water Instrument: A Two-Channel, Tunable Diode Laser-Based Hygrometer for Measurement of Water Vapor and Cirrus Cloud Ice Water Content

    NASA Astrophysics Data System (ADS)

    Fahey, D. W.; Thornberry, T. D.; Rollins, A. W.; Gao, R. S.; Watts, L. A.; Ciciora, S. J.; McLaughlin, R. J.

    2014-12-01

    The recently developed NOAA Water instrument is a two-channel, closed-path, tunable diode laser absorption spectrometer designed for the measurement of water vapor and enhanced total water (vapor + inertially enhanced condensed-phase) from the NASA Global Hawk unmanned aircraft system (UAS) or other high-altitude research aircraft. Combining the measurements from the two channels allows the determination of cloud ice water content (IWC), an important metric for evaluating the radiative properties of cirrus clouds. The instrument utilizes wavelength-modulated spectroscopy with second harmonic detection near 2694 nm to achieve high precision with a 79 cm double-pass optical path. The detection cells are operated under constant temperature, pressure and flow conditions to maintain a constant sensitivity to H2O independent of the ambient sampling environment. An on-board calibration system is used to perform periodic in situ calibrations to verify the stability of the instrument sensitivity during flight. For the water vapor channel, ambient air is sampled perpendicular to the flow past the aircraft in order to reject cloud particles, while the total water channel uses a heated, forward-facing inlet to sample both water vapor and cloud particles. The total water inlet operates subisokinetically, thereby inertially enhancing cloud particle number in the sample flow and affording increased cirrus IWC sensitivity. The NOAA Water instrument was flown for the first time during the second deployment of the Airborne Tropical TRopopause EXperiment (ATTREX) in February-March 2013 on board the Global Hawk UAS. The instrument demonstrated a typical in-flight precision (1 s, 1 σ) of better than 0.17 parts per million (ppm, 10-6 mol/mol), with an overall H2O vapor measurement uncertainty of 5% ± 0.23 ppm. The inertial enhancement for cirrus cloud particle sampling under ATTREX flight conditions ranged from 33-48 for ice particles larger than 8 µm in diameter, depending primarily

  13. High temperature ultralow water content carbon dioxide-in-water foam stabilized with viscoelastic zwitterionic surfactants.

    PubMed

    Alzobaidi, Shehab; Da, Chang; Tran, Vu; Prodanović, Maša; Johnston, Keith P

    2017-02-15

    Ultralow water content carbon dioxide-in-water (C/W) foams with gas phase volume fractions (ϕ) above 0.95 (that is <0.05 water) tend to be inherently unstable given that the large capillary pressures that cause the lamellar films to thin. Herein, we demonstrate that these C/W foams may be stabilized with viscoelastic aqueous phases formed with a single zwitterionic surfactant at a concentration of only 1% (w/v) in DI water and over a wide range of salinity. Moreover, they are stable with a foam quality ϕ up to 0.98 even for temperatures up to 120°C. The properties of aqueous viscoelastic solutions and foams containing these solutions are examined for a series of zwitterionic amidopropylcarbobetaines, R-ONHC3H6N(CH3)2CH2CO2, where R is varied from C12-14 (coco) to C18 (oleyl) to C22 (erucyl). For the surfactants with long C18 and C22 tails, the relaxation times from complex rheology indicate the presence of viscoelastic wormlike micelles over a wide range in salinity and pH, given the high surfactant packing fraction. The apparent viscosities of these ultralow water content foams reached more than 120cP with stabilities more than 30-fold over those for foams formed with the non-viscoelastic C12-14 surfactant. At 90°C, the foam morphology was composed of ∼35μm diameter bubbles with a polyhedral texture. The apparent foam viscosity typically increased with ϕ and then dropped at ϕ values higher than 0.95-0.98. The Ostwald ripening rate was slower for foams with viscoelastic versus non-viscoelastic lamellae as shown by optical microscopy, as a consequence of slower lamellar drainage rates. The ability to achieve high stabilities for ultralow water content C/W foams over a wide temperature range is of interest in various technologies including polymer and materials science, CO2 enhanced oil recovery, CO2 sequestration (by greater control of the CO2 flow patterns), and possibly even hydraulic fracturing with minimal use of water to reduce the requirements for

  14. Simultaneous Monitoring of Soil Water Content and Salinity with a Low-Cost Capacitance-Resistance Probe

    PubMed Central

    Scudiero, Elia; Berti, Antonio; Teatini, Pietro; Morari, Francesco

    2012-01-01

    Capacitance and resistivity sensors can be used to continuously monitor soil volumetric water content (θ) and pore-water electrical conductivity (ECp) with non-destructive methods. However, dielectric readings of capacitance sensors operating at low frequencies are normally biased by high soil electrical conductivity. A procedure to calibrate capacitance-resistance probes in saline conditions was implemented in contrasting soils. A low-cost capacitance-resistance probe (ECH2O-5TE, 70 MHz, Decagon Devices, Pullman, WA, USA) was used in five soils at four water contents (i.e., from dry conditions to saturation) and four salinity levels of the wetting solution (0, 5, 10, and 15 dS·m−1). θ was accurately predicted as a function of the dielectric constant, apparent electrical conductivity (ECa), texture and organic carbon content, even in high salinity conditions. Four models to estimate pore-water electrical conductivity were tested and a set of empirical predicting functions were identified to estimate the model parameters based on easily available soil properties (e.g., texture, soil organic matter). The four models were reformulated to estimate ECp as a function of ECa, dielectric readings, and soil characteristics, improving their performances with respect to the original model formulation. Low-cost capacitance-resistance probes, if properly calibrated, can be effectively used to monitor water and solute dynamics in saline soils. PMID:23250279

  15. The power of size. 1. Rate constants and equilibrium ratios for accumulation of organic substances related to octanol-water partition ratio and species weight.

    PubMed

    Hendriks, A J; van der Linde, A; Cornelissen, G; Sijm, D T

    2001-07-01

    Most of the thousands of substances and species that risk assessment has to deal with are not investigated empirically because of financial, practical, and ethical constraints. To facilitate extrapolation, we have developed a model for accumulation kinetics of organic substances as a function of the octanol-water partition ratio (Kow) of the chemical and the weight, lipid content, and trophic level of the species. The ecological parameters were obtained from a previous review on allometric regressions. The chemical parameters, that is, resistances that substances encounter in water and lipid layers of organisms, were calibrated on 1,939 rate constants for absorption from water for assimilation from food and for elimination. Their ratio was validated on 37 laboratory bioconcentration and biomagnification regressions and on 2,700 field bioaccumulation data. The rate constant for absorption increased with the hydrophobicity of the substances with a Kow up to about 1,000 and then leveled off, decreasing with the weight of the species. About 39% of the variation was explained by the model, while deviations of more than a factor of 5 were noted for labile, large, and less hydrophobic molecules as well as for algae, mollusks, and arthropods. The efficiency for assimilation of contaminants from food was determined mainly by the food digestibility and thus by the trophic level of the species. A distinction was made between substances that are stable, that is, with a minimum elimination only, and those that are labile, that is, with an excess elimination probably largely due to biotransformation. The rate constant for minimum elimination decreased with the hydrophobicity of the substance and the weight of the species. About 70% of the variation was explained by the model, while deviations of more than a factor of 5 were noted for algae, terrestrial plants, and benthic animals. Labile substances were eliminated faster than isolipophilic stable compounds, but differences in

  16. Effective water content reduction in sewage wastewater sludge using magnetic nanoparticles.

    PubMed

    Lakshmanan, Ramnath; Kuttuva Rajarao, Gunaratna

    2014-02-01

    The present work compares the use of three flocculants for sedimentation of sludge and sludge water content from sewage wastewater i.e. magnetic iron oxide nanoparticles (MION), ferrous sulfate (chemical) and Moringa crude extract (protein). Sludge water content, wet/dry weight, turbidity and color were performed for, time kinetics and large-scale experiment. A 30% reduction of the sludge water content was observed when the wastewater was treated with either protein or chemical coagulant. The separation of sludge from wastewater treated with MION was achieved in less than 5min using an external magnet, resulted in 95% reduction of sludge water content. Furthermore, MION formed denser flocs and more than 80% reduction of microbial content was observed in large volume experiments. The results revealed that MION is efficient in rapid separation of sludge with very low water content, and thus could be a suitable alternative for sludge sedimentation and dewatering in wastewater treatment processes.

  17. Running-induced patellofemoral pain fluctuates with changes in patella water content.

    PubMed

    Ho, Kai-Yu; Hu, Houchun H; Colletti, Patrick M; Powers, Christopher M

    2014-01-01

    Although increased bone water content resulting from repetitive patellofemoral joint loading has been suggested to be a possible mechanism underlying patellofemoral pain (PFP), there is little data to support this mechanism. The purpose of the current study was to determine whether running results in increases in patella water content and pain and whether 48 hours of rest reduces patella water content and pain to pre-running levels. Ten female runners with a diagnosis of PFP (mean age 25.1 years) participated. Patella water content was quantified using a chemical-shift-encoded water-fat magnetic resonance imaging (MRI) protocol. The visual analog scale (VAS) was used to quantify subjects' pain levels. MRI and pain data were obtained prior to running, immediately following a 40-minute running session, and 48 hours post-running. Pain and patella water content were compared among the 3 time points using one-way ANOVA's with repeated measures. Immediately post-running, persons with PFP reported significant increases in pain and exhibited elevated patella water content. Pain and patella water content decreased to pre-running levels following 48 hours of rest. Our findings suggest that transient changes in patella water content associated with running may, in part, contribute to patellofemoral symptoms.

  18. Patterns of temporal changes in tissue dielectric constant as indices of localized skin water changes in women treated for breast cancer: a pilot study.

    PubMed

    Mayrovitz, Harvey N; Weingrad, Daniel N; Lopez, Lidice

    2015-03-01

    Our goal was to characterize temporal patterns of skin Tissue Dielectric Constant (TDC) as a foundation for possible TDC use to detect and quantify lymphedema. Although limb volumes and bioimpedance analysis (BIA) are used for this purpose, potential TDC-method advantages are that it can be done in about 10 seconds at any body site to depths from 0.5 to 5.0 mm below the epidermis. TDC at forearm, biceps, axilla, and lateral thorax, and BIA values and arm volumes were measured in 80 women with breast cancer prior to surgery and in decreasing numbers at 3, 6, 12, 18, and 24 months post-surgery. Results show that TDC values, reflecting water content in the measurement volume, vary by site and depth but that at-risk/contralateral side ratio (A/C) is relatively independent of site and depth and is the preferred TDC parameter to detect tissue water changes over time in unilateral conditions. Among sites measured, lateral thorax, followed by forearm, appears most useful for TDC measurements with axilla least useful. Pre-surgery TDC inter-side values and A/C ratios showed no significant inter-side differences, suggesting that breast cancer presence per se did not alter tissue water status in this patient population. Sequential changes in TDC A/C ratios detected a greater number of patients who had inter-arm ratio increases exceeding 10% than were detected using BIA ratios. This may indicate a greater sensitivity to localized tissue water changes with the TDC-method. TDC is a technically viable and potentially useful method to track skin water changes in persons treated for breast cancer.

  19. Mapping soil water content under sparse vegetation and changeable sky conditions: comparison of two thermal inertia approaches

    NASA Astrophysics Data System (ADS)

    Maltese, Antonino; Capodici, Fulvio; Ciraolo, Giuseppe; La Loggia, Goffredo

    2013-01-01

    A critical analysis of a thermal inertia approach to map surface soil water content on bare and sparsely vegetated soils by means of remotely sensed data is reported. The study area is an experimental field located in Barrax, Spain. In situ data were acquired within the Barrax 2011 research project. An advanced hyperspectral scanner airborne imager provides images in the visible/near-infrared and thermal infrared bands. Images were acquired both in day and night times by the Instituto Nacional de Técnica Aeroespacial between 12th and 13th of June 2011. The scene covers a corn irrigation pivot surrounded by bare soil, where a set of in situ data have been collected both previously and simultaneously to overpasses. To validate remotely sensed estimations, an ad hoc dataset has been produced by measuring spectra, radiometric temperatures, surface soil water content, and soil thermal properties. These data were collected on two transects covering bare and sparsely vegetated soils. This ground dataset was used (1) to verify if a thermal inertia method can be applied to map the water content on soil covered by sparse vegetation and (2) to quantify a correction factor accounting for solar radiation reduction due to sky cloudiness. The experiment intended to test a spatially constant and a spatially distributed approach to estimate the phase difference. Both methods were then applied to the airborne images collected during the following days to obtain the spatial distribution of surface soil water content. Results confirm that the thermal inertia method can be applied to sparsely vegetated soil characterized by low fractional cover if the solar radiation reaching the ground is accurately estimated. A spatially constant value of the phase difference allows a good assessment of thermal inertia, whereas the comparison with the three-temperature approach did not give conclusive responses. Results also show that clear sky, only at the time of the acquisition, does not provide

  20. Electrical conductivity of orthopyroxene: Implications for the water content of the asthenosphere

    PubMed Central

    Dai, Lidong; Karato, Shun-ichiro

    2009-01-01

    Electrical conductivity of minerals is sensitive to water content and hence can be used to infer the water content in the mantle. However, previous studies to infer the water content in the upper mantle were based on pure olivine model of the upper mantle. Influence of other minerals particularly that of orthopyroxene needs to be included to obtain a better estimate of water content in view of the high water solubility in this mineral. Here we report new results of electrical conductivity measurements on orthopyroxene, and apply these results to estimate the water content of the upper mantle of Earth. We found that the electrical conductivity of orthopyroxene is enhanced by the addition of water in a similar way as other minerals such as olivine and pyrope garnet. Using these new results, we calculate the electrical conductivity of pyrolite mantle as a function of water content and temperature incorporating the temperature and water fugacity-dependent hydrogen partitioning. Reported values of asthenosphere conductivity of 4 × 10−2−10−1 S/m corresponds to the water content of 0.01–0.04 wt%, a result in good agreement with the petrological model of the upper mantle. PMID:20009379

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

    PubMed

    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.

  2. Impedimetric sensing of the ethanol and water contents in gasohol with a flow-through carbon electrode pair

    NASA Astrophysics Data System (ADS)

    Kung, Yi; Cheng, Tzong-Jih; Chen, Richie L. C.

    2013-10-01

    The ethanol in gasohol was estimated with a flow-through hydrophobic electrode pair (two identical glassy carbon electrodes, cell constant = 0.3 cm-1). Based on the impedimetric signal at 320 Hz, the important fuel quality parameter can be measured in less than 1 s with sufficient temperature tolerance (20-40 °C) and reproducibility (relative standard deviation ≤ 2% for ten tests). The water content can also be estimated by comparing the impedance data obtained with and without desiccation.

  3. Prediction of water content at different potentials from soil property data in Jazan region

    NASA Astrophysics Data System (ADS)

    Alturki, Ali; Ibrahim, Hesham

    2016-04-01

    In dry regions effective irrigation management is crucial to maintain crop production and sustain limited water resources. Effective irrigation requires good knowledge of soil water content in the root zone. However, measurement of soil water in the root zone over time is extremely expensive and time consuming. On the other hand, weather and basic soil property data are more available, either from existing databases or by direct measurement in the field. Simulation models can be used to efficiently and accurately estimate soil water content and subsequent irrigation requirements based on the available weather and soil data. In this study we investigated three hierarchical approaches to predict water content at variable potentials (0, 10, 33, 60, 100, 300, 500, 800, 1000, and 1500 kPa) using the Rosetta model: soil texture class (STC); percent of sand, silt, and clay (SSC); bulk density, percent of sand, silt, and clay, and water content measurements at 33 and 1500 kPa (SSC+WC). Estimation of soil water content at 43 locations in Jazan region using the three hierarchical approaches was compared with gravimetric water content. Results showed that the three approaches failed to describe water content accurately at saturation conditions (<10kPa). At water potentials lower than 10 kPa, good agreement was obtained, in general, between measured and simulated soil water content indicating that soil property data can be used to provide adequate estimates of the average soil water content in the root zone. The third approach gave the best results as indicated by an average NSCE value of 0.75 as compared to 0.16 and 0.18 for the first and second approaches, respectively. The ability to predict the amount of available water in the soil profile will facilitate the accurate estimate of irrigation requirements and achieve effective irrigation scheduling especially in locations where only limited weather and soil date are available.

  4. Water content distribution imaging of skin tissue using near-infrared camera and measurement depth analysis

    NASA Astrophysics Data System (ADS)

    Arimoto, Hidenobu; Egawa, Mariko

    2013-02-01

    Wavelength-dependent light penetration depth in the measurement of water distribution of the skin tissue is analyzed. Near-infrared (NIR) imaging enables 2-D water content map on the skin tissue because water absorbs light strongly in the NIR region particularly around the wavelengths of 1450 and 1920 nm. However, the depth of the light penetration depends largely on wavelength as the absorption coefficient of water changes considerably in the NIR range. We investigate the measurement depth of the water content mapping with a NIR camera and bandpass filters at the wavelengths of 1300, 1450 and 1920 nm. Analysis is performed with Monte Carlo light scattering simulation adopting the optical parameters which is derived from the depth profile of the water contents measured by the confocal Raman spectroscopy. It is found that the NIR image in 1920 nm gives the highest sensitivity to the water content in the surface layer of the skin tissue.

  5. Remote measurement of the water content of snowpacks

    NASA Technical Reports Server (NTRS)

    Linlor, W. I.

    1972-01-01

    Electronic equipment for sensing moisture content of snowpacks is described. Components of electronic test equipment are illustrated and methods of conducting tests are explained. Possibilities for airborne sensing are examined.

  6. A polishing hybrid AER/UF membrane process for the treatment of a high DOC content surface water.

    PubMed

    Humbert, H; Gallard, H; Croué, J-P

    2012-03-15

    The efficacy of a combined AER/UF (Anion Exchange Resin/Ultrafiltration) process for the polishing treatment of a high DOC (Dissolved Organic Carbon) content (>8 mgC/L) surface water was investigated at lab-scale using a strong base AER. Both resin dose and bead size had a significant impact on the kinetic removal of DOC for short contact times (i.e. <15 min). For resin doses higher than 700 mg/L and median bead sizes below 250 μm DOC removal remained constant after 30 min of contact time with very high removal rates (80%). Optimum AER treatment conditions were applied in combination with UF membrane filtration on water previously treated by coagulation-flocculation (i.e. 3 mgC/L). A more severe fouling was observed for each filtration run in the presence of AER. This fouling was shown to be mainly reversible and caused by the progressive attrition of the AER through the centrifugal pump leading to the production of resin particles below 50 μm in diameter. More important, the presence of AER significantly lowered the irreversible fouling (loss of permeability recorded after backwash) and reduced the DOC content of the clarified water to l.8 mgC/L (40% removal rate), concentration that remained almost constant throughout the experiment.

  7. De-coupling seasonal changes in water content and dry matter to predict live conifer foliar moisture content

    Treesearch

    W. Matt Jolly; Ann M. Hadlow; Kathleen Huguet

    2014-01-01

    Live foliar moisture content (LFMC) significantly influences wildland fire behaviour. However, characterising variations in LFMC is difficult because both foliar mass and dry mass can change throughout the season. Here we quantify the seasonal changes in both plant water status and dry matter partitioning. We collected new and old foliar samples from Pinus contorta for...

  8. Constantly stirred sorbent and continuous flow integrative sampler: new integrative samplers for the time weighted average water monitoring.

    PubMed

    Llorca, Julio; Gutiérrez, Cristina; Capilla, Elisabeth; Tortajada, Rafael; Sanjuán, Lorena; Fuentes, Alicia; Valor, Ignacio

    2009-07-31

    Two innovative integrative samplers have been developed enabling high sampling rates unaffected by turbulences (thus avoiding the use of performance reference compounds) and with negligible lag time values. The first, called the constantly stirred sorbent (CSS) consists of a rotator head that holds the sorbent. The rotation speed given to the head generates a constant turbulence around the sorbent making it independent of the external hydrodynamics. The second, called the continuous flow integrative sampler (CFIS) consists of a small peristaltic pump which produces a constant flow through a glass cell. The sorbent is located inside this cell. Although different sorbents can be used, poly(dimethylsiloxane) PDMS under the commercial twister format (typically used for stir bar sorptive extraction) was evaluated for the sampling of six polycyclic aromatic hydrocarbons and three organochlorine pesticides. These new devices have many analogies with passive samplers but cannot truly be defined as such since they need a small energy supply of around 0.5 W supplied by a battery. Sampling rates from 181 x 10(-3) to 791 x 10(-3) L/day were obtained with CSS and 18 x 10(-3) to 53 x 10(-3) with CFIS. Limits of detection for these devices are in the range from 0.3 to 544 pg/L with a precision below 20%. An in field evaluation for both devices was carried out for a 5 days sampling period in the outlet of a waste water treatment plant with comparable results to those obtained with a classical sampling method.

  9. Preliminary assestment of lint cotton water content in gin-drying temperature studies

    USDA-ARS?s Scientific Manuscript database

    Prior studies to measure total water (free and bound) in lint cotton by Karl Fischer Titration showed the method is more accurate and precise than moisture content by standard oven drying. The objective of the current study was to compare the moisture and total water contents from five cultivars de...

  10. Comparison of Vegetation Water Content Estimates From WindSat and MODIS

    USDA-ARS?s Scientific Manuscript database

    Determination of soil moisture content by microwave remote sensing is important for quantifying the global energy, water and biogeochemical cycles. Vegetation water content (VWC, kg m-2) is one of the important parameters for retrieval of soil moisture using passive microwave radiometers. Liquid w...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  12. Ground penetrating radar water content mapping of golf course green sand layers

    USDA-ARS?s Scientific Manuscript database

    Information on the spatial distribution of water content across the sand layer component of a golf course green can be important to golf course superintendents for evaluating drainage effectiveness and scheduling irrigation. To estimate the bulk water content of the sand layer at point locations ac...

  13. Upper Washita River experimental watersheds: Multiyear stability of soil water content profiles

    USDA-ARS?s Scientific Manuscript database

    Scaling in situ soil water content time series data to a large spatial domain is a key element of watershed environmental monitoring and modeling. The primary method of estimating and monitoring large-scale soil water content distributions is via in situ networks. It is critical to establish the s...

  14. Field tests of a down-hole TDR profiling water content measurement system

    USDA-ARS?s Scientific Manuscript database

    Accurate soil profile water content monitoring at multiple depths has previously been possible only using the neutron probe (NP), but with great effort and at unsatisfactory intervals. Despite the existence of several capacitance systems for profile water content measurements, accuracy and spatial r...

  15. Estimating canopy water content of wetland vegetation using hyperspectral and multispectral remote sensing data

    NASA Astrophysics Data System (ADS)

    Sun, Yonghua; Wang, Yihan; Huang, Jin

    2015-10-01

    The canopy water content of wetland vegetation is an important measuring index of the health status of wetland ecosystem. This article takes the Honghe national wetland nature reserve as study area. We focus on innovative approaches for retrieving canopy water content from optical remote sensing data-multispectral and hyperspectral data. Spectral features, such as narrow band spectral indices, hyperspectral vegetation indices in early literatures, absorption features and vegetation indices extracted from TM image were used to estimate the canopy water content. For narrow band spectral indices, Normalized difference vegetation index comprised of 970 nm and at 900 nm had a highest correlation with canopy water content. For general hyperspectral vegetation indices in early literatures, WI had a highest correlation with canopy water content. For absorption features, the absorption deepness at 1200nm had a highest correlation with canopy water content. In addition, NDII (band5) extracted from TM images could be used for estimating canopy water content. Finally, a distribution map of canopy water content in HNNR was generated.

  16. Photosynthesis, chlorophyll fluorescence and spectral reflectance in Sphagnum moss at varying water contents.

    PubMed

    Van Gaalen, K Eric; Flanagan, Lawrence B; Peddle, Derek R

    2007-08-01

    Moss samples from the Fluxnet-Canada western peatland flux station in the Boreal Region of Alberta were measured in the laboratory to obtain the net photosynthesis rate and chlorophyll fluorescence of the moss under controlled environmental conditions, including the regulation of moss water content, simultaneously with measurements of moss spectral reflectance. One objective was to test whether the photochemical reflectance index (PRI) detected changes in moss photosynthetic light-use efficiency that were consistent with short-term (minutes to hours) changes in xanthophyll cycle pigments and associated changes in non-photochemical quenching (NPQ), as recorded by chlorophyll fluorescence. The rate of net photosynthesis was strongly inhibited by water content at values exceeding approximately 9 (fresh weight/dry weight) and declined as the water content fell below values of approximately 8. Chlorophyll fluorescence measurements of maximum photosystem II efficiency generally remained high until the water content was reduced from the maximum of about 20 to values of approximately 10-11, and then declined with further reductions in moss water content. A significant linear decline in NPQ was observed as moss water content was reduced from maximum to low water content values. There was a strong negative correlation between changes in NPQ and PRI. These data suggest that PRI measurements are a good proxy for short-term shifts in photosynthetic activity in Sphagnum moss. A second objective was to test how accurately the water band index (WBI, ratio of reflectance at 900 and 970 nm) recorded changes in moss water content during controlled laboratory studies. Strong linear relationships occurred between changes in moss water content and the WBI, although the slopes of the linear relationships were significantly different among sample replicates. Therefore, WBI appeared to be a useful tool to determine sample-specific water content without destructive measurements.

  17. Henry's law constant and overall mass transfer coefficient for formaldehyde emission from small water pools under simulated indoor environmental conditions.

    PubMed

    Liu, Xiaoyu; Guo, Zhishi; Roache, Nancy F; Mocka, Corey A; Allen, Matt R; Mason, Mark A

    2015-02-03

    The Henry's law constant (HLC) and the overall mass transfer coefficient are both important parameters for modeling formaldehyde emissions from aqueous solutions. In this work, the apparent HLCs for formaldehyde aqueous solutions were determined in the concentration range from 0.01% to 1% (w/w) and at different temperatures (23, 40, and 55 °C) by a static headspace extraction method. The aqueous solutions tested included formaldehyde in water, formaldehyde-water with nonionic surfactant Tergitol NP-9, and formaldehyde-water with anionic surfactant sodium dodecyl sulfate. Overall, the measured HLCs ranged from 8.33 × 10(-6) to 1.12 × 10(-4) (gas-concentration/aqueous-concentration, dimensionless). Fourteen small-chamber tests were conducted with formaldehyde solutions in small pools. By applying the measured HLCs, the formaldehyde overall liquid-phase mass transfer coefficients (KOLs) were determined to be in the range of 8.12 × 10(-5) to 2.30 × 10(-4) m/h, and the overall gas-phase mass transfer coefficients were between 2.84 and 13.4 m/h. The influences of the formaldehyde concentration, temperature, agitation rate, and surfactant on HLC and KOL were investigated. This study provides useful data to support source modeling for indoor formaldehyde originating from the use of household products that contain formaldehyde-releasing biocides.

  18. Nitrate contents of well, raw, treated and pipe borne water in Vom, Plateau State, Nigeria.

    PubMed

    Gbodi, T A; Atawodi, S E

    1987-04-01

    Nitrate content of water available to man and animals in a rural community in Plateau State, Nigeria was determined. Water samples were obtained from artesian wells, raw untreated surface water, treated raw water, and pipe borne water. The examination of the samples was over a period of 3 mo at weekly intervals. Sixty percent of the artesian wells sampled had nitrate concentration above 5-50 ppm in June and August, while samples from other sources had less than 1 ppm. The proximity of pit latrines to some of the wells may have been responsible for high nitrate content of the well water.

  19. Nitrate contents of well, raw, treated and pipe borne water in Vom, Plateau State, Nigeria

    SciTech Connect

    Gbodi, T.A.; Atawodi, S.E.

    1987-04-01

    Nitrate content of water available to man and animals in a rural community in Plateau State, Nigeria was determined. Water samples were obtained from artesian wells, raw untreated surface water, treated raw water, and pipe borne water. The examination of the samples was over a period of 3 mo at weekly intervals. Sixty percent of the artesian wells sampled had nitrate concentration above 5-50 ppm in June and August, while samples from other sources had less than 1 ppm. The proximity of pit latrines to some of the wells may have been responsible for high nitrate content of the well water.

  20. Determining the in situ water content of the Geysers Graywacke of Northern California

    SciTech Connect

    Marsh, A.

    1994-12-01

    The water content, porosity and permeability measurements of the Northern California Geysers rocks are used to predict the lifetime of the geothermal resource, which provides 10% of Northern California`s electricity. The Geysers rock was drilled from defunct well SB-15-D, and some cores wee sealed in aluminum tubes to preserve the in situ water content. These cores were sent to the Lawrence Livermore Laboratory to measure the water content. Humidity measurements were taken of the air around a one and a half foot encased core, recovered from a depth of 918.9 feet. Over a seven day period, the humidity reached almost 100% indicating that the air around the core was saturated in water vapor. We believe the sealing method is effective, preserving the in-situ water content. To measure water content, I will use Archimede`s principle to determine the density of the core before and after drying in an oven. Ultrasonic measurements will be taken of the core upon removal from aluminum tube to determine the change of p-wave velocity with change in water content. Water in the pores increases the effective compressibility of the rock therefore increasing the p-velocity. The measured p-wave velocities can then be used in the field to determine in-situ water content. Three dimensional x-ray images will be used to determine the deviations from average density within individual cores. Since the density depends on water content as well as mineralogy, images can show the location of pore fluid and drilling mud. Archimede`s principle, humidity detection, ultrasonics and x-ray scanning are viable methods to measure the in-situ water content and pore water distribution in the graywacke.

  1. [The new method monitoring crop water content based on NIR-Red spectrum feature space].

    PubMed

    Cheng, Xiao-juan; Xu, Xin-gang; Chen, Tian-en; Yang, Gui-jun; Li, Zhen-hai

    2014-06-01

    Moisture content is an important index of crop water stress condition, timely and effective monitoring of crop water content is of great significance for evaluating crop water deficit balance and guiding agriculture irrigation. The present paper was trying to build a new crop water index for winter wheat vegetation water content based on NIR-Red spectral space. Firstly, canopy spectrums of winter wheat with narrow-band were resampled according to relative spectral response function of HJ-CCD and ZY-3. Then, a new index (PWI) was set up to estimate vegetation water content of winter wheat by improveing PDI (perpendicular drought index) and PVI (perpendicular vegetation index) based on NIR-Red spectral feature space. The results showed that the relationship between PWI and VWC (vegetation water content) was stable based on simulation of wide-band multispectral data HJ-CCD and ZY-3 with R2 being 0.684 and 0.683, respectively. And then VWC was estimated by using PWI with the R2 and RMSE being 0.764 and 0.764, 3.837% and 3.840%, respectively. The results indicated that PWI has certain feasibility to estimate crop water content. At the same time, it provides a new method for monitoring crop water content using remote sensing data HJ-CCD and ZY-3.

  2. Influence of water content on Raman spectroscopy characterization of skin sample

    PubMed Central

    Kim, Soogeun; Byun, Kyung Min; Lee, Soo Yeol

    2017-01-01

    We report that the Raman spectrum obtained from porcine skin varies significantly with the change of skin water content. At different water contents from 40 to 55 wt.%, the Raman spectra results using confocal Raman spectroscopy show that the spectral variation of porcine skin is highly affected by skin water content. Experimental data are consistent with the Monte Carlo calculation and it is proved that the intensity of the Raman spectrum depends on the angle distribution and collection efficiency of backscattered light from the sample surface for a varied water content. It is suggested that water content for a given skin sample should be controlled carefully to minimize errors and deviations in the Raman peak analyses. PMID:28271008

  3. Snowpack in Maine - Maximum Observed and March 1 Mean Equivalent Water Content

    USGS Publications Warehouse

    Loiselle, Marc C.; Hodgkins, Glenn A.

    2002-01-01

    Historical snow data have been analyzed using geographic information systems software to determine the magnitude and distribution of maximum observed equivalent water content of snowpack for the State of Maine. Data from 109 sites with an average of 43 years of record were used to generate the map of maximum observed equivalent water content. Maximum observed water content ranged from less than 8 inches in south-coastal Maine to more than 20 inches in the northwestern mountains. A map of mean equivalent water content in snowpack on or about March 1 also was prepared with data from these sites. The March 1 mean equivalent water content ranged from less than 4 inches near the coast to more than 9 inches in northern Maine.

  4. Influence of water content on Raman spectroscopy characterization of skin sample.

    PubMed

    Kim, Soogeun; Byun, Kyung Min; Lee, Soo Yeol

    2017-02-01

    We report that the Raman spectrum obtained from porcine skin varies significantly with the change of skin water content. At different water contents from 40 to 55 wt.%, the Raman spectra results using confocal Raman spectroscopy show that the spectral variation of porcine skin is highly affected by skin water content. Experimental data are consistent with the Monte Carlo calculation and it is proved that the intensity of the Raman spectrum depends on the angle distribution and collection efficiency of backscattered light from the sample surface for a varied water content. It is suggested that water content for a given skin sample should be controlled carefully to minimize errors and deviations in the Raman peak analyses.

  5. Interaction of ionic liquid with water with variation of water content in 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6])/TX-100/water ternary microemulsions monitored by solvent and rotational relaxation of coumarin 153 and coumarin 490.

    PubMed

    Seth, Debabrata; Chakraborty, Anjan; Setua, Palash; Sarkar, Nilmoni

    2007-06-14

    The interaction of water with room temperature ionic liquid (RTIL) [bmim][PF6] has been studied in [bmim][PF6]/TX-100/water ternary microemulsions by solvent and rotational relaxation of coumarin 153 (C-153) and coumarin 490 (C-490). The rotational relaxation and average solvation time of C-153 and C-490 gradually decrease with increase in water content of the microemulsions. The gradual increase in the size of the microemulsion with increase in w0 (w0=[water]/[surfactant]) is evident from dynamic light scattering measurements. Consequently the mobility of the water molecules also increases. In comparison to pure water the retardation of solvation time in the RTIL containing ternary microemulsions is very less. The authors have also reported the solvation time of C-490 in neat [bmim][PF6]. The solvation time of C-490 in neat [bmim][PF6] is bimodal with time constants of 400 ps and 1.10 ns.

  6. Interaction of ionic liquid with water with variation of water content in 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6])/TX-100/water ternary microemulsions monitored by solvent and rotational relaxation of coumarin 153 and coumarin 490

    NASA Astrophysics Data System (ADS)

    Seth, Debabrata; Chakraborty, Anjan; Setua, Palash; Sarkar, Nilmoni

    2007-06-01

    The interaction of water with room temperature ionic liquid (RTIL) [bmim][PF6] has been studied in [bmim][PF6]/TX-100/water ternary microemulsions by solvent and rotational relaxation of coumarin 153 (C-153) and coumarin 490 (C-490). The rotational relaxation and average solvation time of C-153 and C-490 gradually decrease with increase in water content of the microemulsions. The gradual increase in the size of the microemulsion with increase in w0 (w0=[water]/[surfactant]) is evident from dynamic light scattering measurements. Consequently the mobility of the water molecules also increases. In comparison to pure water the retardation of solvation time in the RTIL containing ternary microemulsions is very less. The authors have also reported the solvation time of C-490 in neat [bmim][PF6]. The solvation time of C-490 in neat [bmim][PF6] is bimodal with time constants of 400ps and 1.10ns.

  7. Growth and transpiration of Japanese cedar (Cryptomeria japonica) and Hinoki cypress (Chamaecyparis obtusa) seedlings in response to soil water content.

    PubMed

    Nagakura, Junko; Shigenaga, Hidetoshi; Akama, Akio; Takahashi, Masamichi

    2004-11-01

    To investigate the effects of soil water content on growth and transpiration of Japanese cedar (Cryptomeria japonica D. Don) and Hinoki cypress (Chamaecyparis obtusa (Siebold et Zucc.) Endl.), potted seedlings were grown in well-watered soil (wet treatment) or in drying soil (dry treatment) for 12 weeks. Seedlings in the wet treatment were watered once every 2 or 3 days, whereas seedlings in the dry treatment were watered when soil water content (Theta; m3 m(-3)) reached 0.30, equivalent to a soil matric potential of -0.06 MPa. From Weeks 7 to 12 after the onset of the treatments, seedling transpiration was measured by weighing the potted seedlings. After the last watering, changes in transpiration rate during soil drying were monitored intensely. The dry treatment restricted aboveground growth but increased biomass allocation to the roots in both species, resulting in no significant treatment difference in whole-plant biomass production. The species showed similar responses in relative growth rate (RGR), net assimilation rate (NAR) and shoot mass ratio (SMR) to the dry treatment. Although NAR did not change significantly in either C. japonica or C. obtusa as the soil dried, the two species responded differently to the dry treatment in terms of mean transpiration rate (E) and water-use efficiency (WUE), which are parameters that relate to NAR. In the dry treatment, both E and WUE of C. japonica were stable, whereas in C. obtusa, E decreased and WUE increased (E and WUE counterbalanced to maintain a constant NAR). Transpiration rates were lower in C. obtusa seedlings than in C. japonica seedlings, even in well-watered conditions. During soil drying, the transpiration rate decreased after Theta reached about 0.38 (-0.003 MPa) in C. obtusa and 0.32 (-0.028 MPa) in C. japonica. We conclude that C. obtusa has more water-saving characteristics than C. japonica, particularly when water supply is limited.

  8. Measurements of water content in hydroxypropyl-methyl-cellulose based hydrogels via texture analysis.

    PubMed

    Lamberti, Gaetano; Cascone, Sara; Cafaro, Maria Margherita; Titomanlio, Giuseppe; d'Amore, Matteo; Barba, Anna Angela

    2013-01-30

    In this work, a fast and accurate method to evaluate the water content in a cellulose derivative-based matrix subjected to controlled hydration was proposed and tuned. The method is based on the evaluation of the work of penetration required in the needle compression test. The work of penetration was successfully related to the hydrogel water content, assayed by a gravimetric technique. Moreover, a fitting model was proposed to correlate the two variables (the water content and the work of penetration). The availability of a reliable tool is useful both in the quantification of the water uptake phenomena, both in the management of the testing processes of novel pharmaceutical solid dosage forms.

  9. Evaluation of minerals content of drinking water in Malaysia.

    PubMed

    Azlan, Azrina; Khoo, Hock Eng; Idris, Mohd Aizat; Ismail, Amin; Razman, Muhammad Rizal

    2012-01-01

    The drinking and mineral water samples obtained from different geographical locations had concentrations of the selected minerals lower than the standard limits, except for manganese, arsenic, and fluoride. The concentrations of manganese and arsenic in two mineral water samples were slightly higher than the standard international recommended limits. One mineral water sample had a fluoride concentration higher than the standard limits, whereas manganese was not detected in nine drinking and mineral water samples. Most of the selected minerals found in the tap water samples were below the international standard limits, except for iron and manganese. The concentrations of iron and manganese in the tap water samples were higher than the standard limits, which were obtained from one and three of the studied locations, respectively. The potable water obtained from various manufacturers and locations in Peninsular Malaysia is safe for consumption, as the minerals concentrations were below the standard limits prescribed by the Malaysian Food Regulations of 1985. The data obtained may also provide important information related to daily intake of these minerals from drinking water.

  10. Evaluation of Minerals Content of Drinking Water in Malaysia

    PubMed Central

    Azlan, Azrina; Khoo, Hock Eng; Idris, Mohd Aizat; Ismail, Amin; Razman, Muhammad Rizal

    2012-01-01

    The drinking and mineral water samples obtained from different geographical locations had concentrations of the selected minerals lower than the standard limits, except for manganese, arsenic, and fluoride. The concentrations of manganese and arsenic in two mineral water samples were slightly higher than the standard international recommended limits. One mineral water sample had a fluoride concentration higher than the standard limits, whereas manganese was not detected in nine drinking and mineral water samples. Most of the selected minerals found in the tap water samples were below the international standard limits, except for iron and manganese. The concentrations of iron and manganese in the tap water samples were higher than the standard limits, which were obtained from one and three of the studied locations, respectively. The potable water obtained from various manufacturers and locations in Peninsular Malaysia is safe for consumption, as the minerals concentrations were below the standard limits prescribed by the Malaysian Food Regulations of 1985. The data obtained may also provide important information related to daily intake of these minerals from drinking water. PMID:22649292

  11. Complexation of DTPA and EDTA with Cd(2+): stability constants and thermodynamic parameters at the soil-water interface.

    PubMed

    Karak, Tanmoy; Paul, Ranjit Kumar; Das, Dilip Kumar; Boruah, Romesh Kumar

    2016-12-01

    Two alkaline soils collected from the surface horizon (0-15 cm) of two agricultural fields Lakshmikantapur (LKP; 22° 06' 03″ N and 88° 18' 19″ E) and Diamond Harbour (DHB; 22° 11' N and 88° 14' E) of West Bengal, India were studied to observe the stability of cadmium (Cd) chelate complexes with diethylenetriaminepentaacetatic acid (DTPA) and ethylenediaminetetraacetic acid (EDTA), removing organic matter (OM). The objective of the present study is "determination of the stability constants and the thermodynamic parameters of Cd-DTPA and Cd-EDTA complexes at different pH and temperatures at the soil-water interface". Complex formation of soil Cd with DTPA and EDTA at the soil-water interface was studied under different ligand-to-metal ratios, pHs and temperatures. Apparent conditional stability constants (log k´) were calculated from the concentrations of Cd chelates and free Cd(2+), estimated by solid phase extraction with an ion exchanger. Standard Gibbs energy (ΔG°), standard enthalpy (ΔH°) and standard entropy (ΔS°) of formation were calculated at three different temperatures. The higher stability constants of Cd-DTPA than Cd-EDTA indicated longer persistence of Cd-DTPA at the soil solution interface than Cd-EDTA complex. Increase of ΔG°, ΔH° and ΔS° with progress of temperature revealed that Cd-complex formation was facilitated by temperature. Highly negative ΔG° and positive ΔH° for Cd-complex formation indicated the reaction spontaneous and exothermic. In general, both ligands complexed high percentages of cadmium signalling their role in enhancing remobilization of Cd present in soil and preventing exchange of contaminated Cd from external source with soil mineral matrix; these phenomena may greatly reduce hazard for environment and human health. The result of this study support that DTPA increases solubility and more persistence of Cd in acidic soils within the range of temperature and mole fraction (MF = moles of Cd(2+)

  12. Watering cattle (young bulls) with brackish water--a hazard due to its salt content?

    PubMed

    Visscher, C F; Witzmann, S; Beyerbach, M; Kamphues, J

    2013-01-01

    The aim of this experimental study was primarily to test the effects and reactions of cattle offered salty water as the only source of drinking water. Mineral balance studies were carried out on three bull, continuously fed a ration based on hay, hay cobs, barley, soybean meal and a vitamin/mineral supplement. The salt content of the drinking water varied between the trials (trials I/II/III: 0.10/5.00/10.0 g/l; town water supplemented by different amounts of an additive containing 95.4% sodium chloride and 4.6% potassium chloride). Rising salt concentration of the drinking water led to significantly higher sodium, potassium and chloride intake (sodium: trial I/II/III = 5.42/59.5/ 157 g/day; potassium: trials I/II/III = 108/117/121 g/day; chloride: trials I/II/III = 22.8/112/266 g/day) mainly caused by a significantly higher water intake (trials I/II/III: 21.8 ± 2.03/30.4 ± 3.08/41.5 ± 5.89 kg/day). Amounts of urine increased significantly (trials I/II/III: 3.99 ± 0.46/ 9.66 ± 1.34/20.2 ± 3.14 kg/day). The concentrations of minerals in the urine (sodium: trials I/II/III = 123/3729/6705 mg/kg; potassium: trials I/II/III = 17345/9996/ 5496 mg/kg; chloride: trials I/II/III = 2020/ 9672/11870 mg/kg) and faeces (sodium: trials I/II/III = 1299/6544/ 7653 mg/kg; potassium: trials I/II/III = 6343/3719/3490 mg/kg; chloride: trials I/II/III = 3851/4580/4693 mg/kg) also changed significantly over time. Serum values of sodium tended to decrease (trials I/II/III: 142/137/137 mmol/l) within the physiological range, whereas those of chloride increased (trials I/II/III: 91.5/95.6/97.5 mmol/l) at higher salt concentrations in drinking water. The haematocrit, pH-value as well as urea content in blood were not affected by the higher salt intake. In balance trial III (highest salt load: 10.0 g/l), sodium intake of the bulls reached 0.57 ± 0.03 g/kg BW (~22.1 ± 0.9 g sodium/kg dry matter feed). An increase of salinity in drinking water up to 10 g/l--with otherwise harmless water

  13. Thermal properties of ration components as affected by moisture content and water activity during freezing.

    PubMed

    Li, J; Chinachoti, P; Wang, D; Hallberg, L M; Sun, X S

    2008-11-01

    Beef roast with vegetables is an example of a meal, ready-to-eat (MRE) ration entrée. It is a mixture of meat, potato, mushroom, and carrot with a gravy sauce. The thermal properties of each component were characterized in terms of freezing point, latent heat, freezable and unfreezable water contents, and enthalpy during freezing using differential scanning calorimetry. Freezing and thawing curves and the effect of freezing and thawing cycles on thermal properties were also evaluated. The freezing points of beef, potato, mushroom, and sauce were all in the range of -5.1 to -5.6 degrees C, but moisture content, water activity, latent heat, freezable and unfreezable water contents, and enthalpy varied among these components. Freezing temperature greatly affected the unfrozen water fraction. The unfreezable water content (unfrozen water fraction at -50 degrees C) of ration components was in the range of 8.2% to 9.7%. The freezing and thawing curves of vegetables with sauce differed from those of beef but took similar time to freeze or thaw. Freezing and thawing cycles did not greatly affect the thermal properties of each component. Freezing point and latent heat were reduced by decreasing moisture content and water activity of each component. Water activity was proportionally linear to freezing point at a(w) > 0.88, and moisture content was proportionally linear to freezable water content in all ration components. Water was not available for freezing when moisture content was reduced to 28.8% or less. This study indicates that moisture content and water activity are critical factors affecting thermal behavior of ration components during freezing.

  14. Radar Measurement of Water Content Dynamics Over Bare and Vegetated Soil Surfaces

    NASA Astrophysics Data System (ADS)

    Serbin, G.; Or, D.

    2002-12-01

    Recent studies have shown substantial temperature dependence of microwave dielectric properties of soil-water mixtures, which could affect water content inferences from radar backscatter. Soil drying patterns were measured using ground-penetrating radar (GPR) with a 1 GHz center frequency horn antenna that was suspended (> 0.5 m) over bare and vegetated surfaces of soils with different textures. Soil water contents were derived from the surface reflection (SR) amplitudes and the propagation times (PT) to subsurface reflective interfaces. GPR-SR and -PT water content measurements over bare soil surfaces were in good agreement with gravimetric and time domain reflectometry (TDR) measured values. Measurements over vegetated surfaces showed gradual reductions in the maximal values of GPR-SR measured water contents with increase in plant canopy height. In contrast, the maximal value of GPR-PT-derived water content remained unchanged. Aboveground canopy reflections became more pronounced with canopy growth. GPR-SR data showed noticeable diurnal patterns in water contents of bare surfaces. Water content extreme values vary with soil type - for low surface area soils (sand), the maximum occurs at nighttime, whereas for high surface area soils (clay loam) the maximum occurs around midday at normal incidence. An increase in incidence angle caused a shift in measured maxima times to morning hours. These measurements highlight the need for improved understanding of physical effects on dynamics of near-surface radar measurements often used for hydrological studies.

  15. Determination of Trace Water Content in Petroleum and Petroleum Products.

    PubMed

    Frink, Lillian A; Armstrong, Daniel W

    2016-08-16

    Measurement of water in petroleum and petroleum-based products is of industrial and economic importance; however, the varied and complex matrixes make the analyses difficult. These samples tend to have low amounts of water and contain many compounds which react with iodine, causing Karl Fischer titration (KFT) to give inaccurate, typically higher, results. A simple, rapid, automated headspace gas chromatography (HSGC) method which requires modified instrumentation and ionic liquid stationary phases was developed. Measurement of water in 12 petroleum products along with 3 National Institute of Standards and Technology reference materials was performed with the developed method. The range of water found in these samples was ∼12-3300 ppm. This approach appeared to be unaffected by complicated matrixes. The solvent-free nature of the HSGC method also negates the solubility limitations which are common with KFT.

  16. Variation in Water Content in Martian Subsurface Along Curiosity Traverse

    NASA Image and Video Library

    2013-03-18

    This set of graphs shows variation in the amount and the depth of water detected beneath NASA Mars rover Curiosity by use of the rover Dynamic Albedo of Neutrons DAN instrument at different points the rover has driven.

  17. Fluoride Content of Bottled Drinking Waters in Qatar.

    PubMed

    Almulla, Hessa Ibrahim; King, Nigel M; Alnsour, Hamza Mohammad; Sajnani, Anand K

    2016-12-01

    Fluoridation of drinking water has been recognized as one of the most effective ways of achieving community-wide exposure to the caries prevention effects of fluoride (F). A vast majority of people in Qatar use bottled water for drinking. Use of bottled water without knowing the F level may expose children to dental caries risk if the F level is lower than optimal or to dental fluorosis if the F level is too high. The aim of this study was to determine the F concentration of bottled water available in Qatar. A total of 32 brands of bottled water were evaluated. The F concentrations displayed on the labels were recorded. The F ion-selective electrode method was used to measure the F concentration in water samples, and three measurements were taken for every sample to ensure reproducibility. The p value was set at 0.05. The F concentration ranged from 0.06 to 3.0 ppm with a mean value of 0.8 ppm (±0.88). The F levels were provided by the manufacturers on the labels of 60 % of the samples, but this was significantly lower than the measured F levels (p < 0.0001). Moreover, bottled water that was produced in Saudi Arabia had significantly higher levels of F when compared to those produced in other countries (p < 0.05). There was a wide variation in the F levels in the different brands of bottled water. Furthermore, there was a significant disparity between the F levels which were measured and those that were provided on the labels.

  18. Influence of Water Content on Mechanical Properties of Rock in Both Saturation and Drying Processes

    NASA Astrophysics Data System (ADS)

    Zhou, Zilong; Cai, Xin; Cao, Wenzhuo; Li, Xibing; Xiong, Cheng

    2016-08-01

    Water content has a pronounced influence on the properties of rock materials, which is responsible for many rock engineering hazards, such as landslides and karst collapse. Meanwhile, water injection is also used for the prevention of some engineering disasters like rock-bursts. To comprehensively investigate the effect of water content on mechanical properties of rocks, laboratory tests were carried out on sandstone specimens with different water contents in both saturation and drying processes. The Nuclear Magnetic Resonance technique was applied to study the water distribution in specimens with variation of water contents. The servo-controlled rock mechanics testing machine and Split Hopkinson Pressure Bar technique were used to conduct both compressive and tensile tests on sandstone specimens with different water contents. From the laboratory tests, reductions of the compressive and tensile strength of sandstone under static and dynamic states in different saturation processes were observed. In the drying process, all of the saturated specimens could basically regain their mechanical properties and recover its strength as in the dry state. However, for partially saturated specimens in the saturation and drying processes, the tensile strength of specimens with the same water content was different, which could be related to different water distributions in specimens.

  19. Effects of stomatal density and leaf water content on the ¹⁸O enrichment of leaf water.

    PubMed

    Larcher, Leticia; Hara-Nishimura, Ikuko; Sternberg, Leonel

    2015-04-01

    Leaf water isotopic composition is imprinted in several biomarkers of interest and it is imperative that we understand the isotopic enrichment of leaf water. Here, we test the effect of stomatal density and leaf water content on the oxygen isotopic composition of leaf water in transgenic Arabidopsis plants expressing different stomatal densities, and several other species showing a range of stomatal density. We grew Arabidopsis plants hydroponically and collected other species in the field. Stomatal density and leaf water content were determined for each plant. We measured transpiration and extracted leaf water for isotopic determination. Using these measurements and the current leaf water isotope model, we calculated several of the parameters related to leaf water isotopic enrichment. High stomatal density promoted leaf water isotope enrichment. No conclusion, however, can be drawn regarding the effect of leaf water content on leaf water isotope enrichment. Factors such as transpiration might mask the effect of stomatal density on leaf water isotopic enrichment. We propose a method by which stomatal density can be incorporated in the current Peclet model of leaf water isotope enrichment. These findings have important applications in the use of plant-based metabolic proxies in paleoclimate studies.

  20. Determining the association constant and adsorption properties of ion pairs in water by fitting surface tension data.

    PubMed

    Pradines, Vincent; Lavabre, Dominique; Micheau, Jean-Claude; Pimienta, Véronique

    2005-11-22

    Association constants and adsorption parameters of tetraalkylammoniumdodecyl sulfate (TAADS) ion pairs in water were determined. We have analyzed water/air surface tension measurements obtained for mixtures of sodium dodecyl sulfate (SDS) and tetraalkylammonium bromide of increasing chain lengths (TMAB, TEAB, TPAB, and TBAB). To reproduce the experimental isotherms, we coupled the association equilibrium of the ion pairs to the equations proposed by Fainerman and co-workers to model the adsorption of binary mixtures of surfactants (SDS and TAADS) with different molar areas at a nonideal surface layer. The parameters found showed that the model is not convenient to describe the effect of the addition of TMAB but a clear coherency was obtained for the three longer compounds. Ranging from TEADS to TBADS increasing hydrophobic interactions give rise to a higher associability but to a lower surface activity. Self-interactions coefficients extracted by the fitting procedure confirmed the importance of attractive interactions between the ion pairs. The calculated surface coverage showed that in every case the compound mainly adsorbed at the interface was the ion pair. For TBADS strong attractive interactions result in a phase transition at very low concentration.

  1. Constant Molybdenum Isotope Composition of Ocean Water and Fe-Mn crusts for the Last 70 Myr

    NASA Astrophysics Data System (ADS)

    Siebert, C.; Nagler, T. F.; von Blankenburg, F.; Kramers, J. D.

    2001-12-01

    .3 and -2 per mil) show composition inbetween. A depth profile through a 70Ma old Fe-Mn crust revealed steep gradients for Mo concentrations (300ppm to 400ppm within 2 Myr), precluding post-depositional homogenisation of Mo. In contrast, the Mo isotopic compositions are uniform throughout the entire 70 Myr profile (-3.2 +/- 0.1 per mil relative to 98Mo/95Mo MOMO). We conclude, that a constant Mo isotopic composition must be assumed for ocean water during the last 70 Myr.

  2. Mineral content of sorghum genotypes and the influence of water stress.

    PubMed

    Paiva, Caroline Liboreiro; Queiroz, Valéria Aparecida Vieira; Simeone, Maria Lúcia Ferreira; Schaffert, Robert Eugene; de Oliveira, Antônio Carlos; da Silva, Camila Santana

    2017-01-01

    Sorghum is a source of several minerals whose content may vary depending on the genotype and the production environment. The objective of this study was to screen sorghum genotypes for mineral content and to investigate the effect of water stress on it. A large variability was observed in the mineral content of 100 sorghum genotypes grown in environments without (WoWS) and with water stress (WthWS). The water stress decreased Mn, P, Mg and S contents in 100, 96, 93 and 56% of genotypes, respectively. The genotypes and other factors seemed to have more impact than water stress on K, Ca, Cu, Fe and Zn levels. In 100 sorghum genotypes, 2 were classified as excellent sources of Fe and 25 of Zn, in both environments. The best two genotypes to Fe content were SC21 and SC655 and to Zn were SC320 and SHAN-QUI-RED which showed great potential for use in biofortification.

  3. Rapid assessment of water pollution by airborne measurement of chlorophyll content.

    NASA Technical Reports Server (NTRS)

    Arvesen, J. C.; Weaver, E. C.; Millard, J. P.

    1971-01-01

    Present techniques of airborne chlorophyll measurement are discussed as an approach to water pollution assessment. The differential radiometer, the chlorophyll correlation radiometer, and an infrared radiometer for water temperature measurements are described as the key components of the equipment. Also covered are flight missions carried out to evaluate the capability of the chlorophyll correlation radiometer in measuring the chlorophyll content in water bodies with widely different levels of nutrients, such as fresh-water lakes of high and low eutrophic levels, marine waters of high and low productivity, and an estuary with a high sediment content. The feasibility and usefulness of these techniques are indicated.

  4. Formulation and make-up of simulated acidic concentrated water (SAW), high ionic content aqueous solution

    SciTech Connect

    Gdowski, G.

    1996-09-30

    This procedure describes the formulation and make-up of Simulated Acidified Water (SAW), a high-ionic-content water to be used for Activity E-20-50 ''Long-Term Corrosion Studies.'' Acidic solutions at the repository may result as a consequence of microbial activity. In formulating the ionic composition of the SAW, it was attempted to simulate the acidification of high ionic content water contacting a waste package. Therefore, the composition of this water is based on the acidification of the Simulated Concentrated Water (SCW), which is described in TIP-CM-07. The pH of the solution will be controlled at a nominal value of 2.

  5. Design of access-tube TDR sensor for soil water content: Testing

    USDA-ARS?s Scientific Manuscript database

    Soil water measurement is important in water management for irrigation and hydrologic sciences. The purpose of this paper is to develop and test the design of a cylindrical access-tube mounted waveguide for use in time-domain reflectometry (TDR) for in-situ soil water content sensing. Several prot...

  6. Fresh Water Content Variability in the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Proshutinsky, Andrey

    2003-01-01

    Arctic Ocean model simulations have revealed that the Arctic Ocean has a basin wide oscillation with cyclonic and anticyclonic circulation anomalies (Arctic Ocean Oscillation; AOO) which has a prominent decadal variability. This study explores how the simulated AOO affects the Arctic Ocean stratification and its relationship to the sea ice cover variations. The simulation uses the Princeton Ocean Model coupled to sea ice. The surface forcing is based on NCEP-NCAR Reanalysis and its climatology, of which the latter is used to force the model spin-up phase. Our focus is to investigate the competition between ocean dynamics and ice formation/melt on the Arctic basin-wide fresh water balance. We find that changes in the Atlantic water inflow can explain almost all of the simulated fresh water anomalies in the main Arctic basin. The Atlantic water inflow anomalies are an essential part of AOO, which is the wind driven barotropic response to the Arctic Oscillation (AO). The baroclinic response to AO, such as Ekman pumping in the Beaufort Gyre, and ice meldfreeze anomalies in response to AO are less significant considering the whole Arctic fresh water balance.

  7. NMR study on mechanisms of ionic polymer-metal composites deformation with water content

    NASA Astrophysics Data System (ADS)

    Zhu, Zicai; Chen, Hualing; Wang, Yongquan; Luo, Bin; Chang, Longfei; Li, Bo; Chen, Luping

    2011-10-01

    Ionic polymer-metal composites (IPMCs) exhibit a large dynamic bending deformation under exterior electric field. The states and proportions of water within the IPMCs have great effect on the IPMCs deformation properties. This letter investigates the influence of the proportion changes of different types of water on the deformation, which may disclose the working mechanisms of the IPMCs. We give a deformation trend of IPMCs with the reduction of water content firstly. Then by the method of nuclear magnetic resonance, various water types (water bonded to sulfonates, loosely bound water and free water) of IPMCs and their proportions are investigated in the drying process which corresponds to their different deformation states. It is obtained that the deformation properties of IPMCs depend strongly on their water content and the excess free water is responsible for the relaxation deformation.

  8. Remote sensing of atmospheric water content from Bhaskara SAMIR data. [using statistical linear regression analysis

    NASA Technical Reports Server (NTRS)

    Gohil, B. S.; Hariharan, T. A.; Sharma, A. K.; Pandey, P. C.

    1982-01-01

    The 19.35 GHz and 22.235 GHz passive microwave radiometers (SAMIR) on board the Indian satellite Bhaskara have provided very useful data. From these data has been demonstrated the feasibility of deriving atmospheric and ocean surface parameters such as water vapor content, liquid water content, rainfall rate and ocean surface winds. Different approaches have been tried for deriving the atmospheric water content. The statistical and empirical methods have been used by others for the analysis of the Nimbus data. A simulation technique has been attempted for the first time for 19.35 GHz and 22.235 GHz radiometer data. The results obtained from three different methods are compared with radiosonde data. A case study of a tropical depression has been undertaken to demonstrate the capability of Bhaskara SAMIR data to show the variation of total water vapor and liquid water contents.

  9. Remote sensing of atmospheric water content from Bhaskara SAMIR data. [using statistical linear regression analysis

    NASA Technical Reports Server (NTRS)

    Gohil, B. S.; Hariharan, T. A.; Sharma, A. K.; Pandey, P. C.

    1982-01-01

    The 19.35 GHz and 22.235 GHz passive microwave radiometers (SAMIR) on board the Indian satellite Bhaskara have provided very useful data. From these data has been demonstrated the feasibility of deriving atmospheric and ocean surface parameters such as water vapor content, liquid water content, rainfall rate and ocean surface winds. Different approaches have been tried for deriving the atmospheric water content. The statistical and empirical methods have been used by others for the analysis of the Nimbus data. A simulation technique has been attempted for the first time for 19.35 GHz and 22.235 GHz radiometer data. The results obtained from three different methods are compared with radiosonde data. A case study of a tropical depression has been undertaken to demonstrate the capability of Bhaskara SAMIR data to show the variation of total water vapor and liquid water contents.

  10. Microwave profiling of snowpack free-water content

    NASA Technical Reports Server (NTRS)

    Linlor, W. I.; Meier, M. F.; Smith, J. L.

    1974-01-01

    A microwave system is proposed to measure the amount of liquid-phase water in a snowpack operating in the range of 1 to 10 GHz. Attenuation of the beam between source and receivers is produced by the water in the snow. The relationships of frequency, distance, and volume percent of water are calculated for an assumed detector sensitivity, together with the estimated cost of a representative system. A laboratory test is described that shows the attenuation for snow at maximum wetness at 9.35 GHz. A configuration is proposed that involves a vertical tube containing microwave and radioactive sources and another vertical tube containing microwave and gamma-ray detectors, so that density and wetness profiles are obtained simultaneously over essentially the same path.

  11. The reliability and validity of hand-held refractometry water content measures of hydrogel lenses.

    PubMed

    Nichols, Jason J; Mitchell, G Lynn; Good, Gregory W

    2003-06-01

    To investigate within- and between-examiner reliability and validity of hand-held refractometry water content measures of hydrogel lenses. Nineteen lenses of various nominal water contents were examined by two examiners on two occasions separated by 1 hour. An Atago N2 hand-held refractometer was used for all water content measures. Lenses were presented in a random order to each examiner by a third party, and examiners were masked to any potential lens identifiers. Intraclass correlation coefficients (ICC), 95% limits of agreement, and Wilcoxon signed rank test were used to characterize the within- and between-examiner reliability and validity of lens water content measures. Within-examiner reliability was excellent (ICC, 0.97; 95% limits of agreement, -3.6% to +5.7%), and the inter-visit mean difference of 1.1 +/- 2.4% was not biased (p = 0.08). Between-examiner reliability was also excellent (ICC, 0.98; 95% limits of agreement, -4.1% to +3.9%). The mean difference between examiners was -0.1 +/- 2.1% (p = 0.83). The mean difference between the nominally reported water content and our water content measures was -2.1 +/- 1.7% (p < 0.001); the 95% limits of agreement for this difference were -5.4% to +1.1%. There is good reliability within and between examiners in measuring water content of hydrogel lenses. However, with our sample of lenses, examiners tended to overestimate the nominal water content of hydrogel lenses. As discussed, this bias may be associated with the Brix scale used in refractometry and is material dependent. Therefore, investigators may need to account for bias when measuring hydrogel lens water content via hand-held refractometry.

  12. Compaction Control of Earth-Rock Mixtures: How to Develop and Use Density Interference Coefficients and Optimum Water Content Factors

    DTIC Science & Technology

    1992-04-01

    oversized fraction is substituted for the water content of the oversized fraction Wc . The absorption A is defined as the satu- rated surface- dry water content...approximately within the specified fill place- ment range. In calculating the quantity of water to add, con- sider the air- dry water content of the material

  13. A Virtual Mixture Approach to the Study of Multistate Equilibrium: Application to Constant pH Simulation in Explicit Water

    PubMed Central

    Wu, Xiongwu; Brooks, Bernard R.

    2015-01-01

    Chemical and thermodynamic equilibrium of multiple states is a fundamental phenomenon in biology systems and has been the focus of many experimental and computational studies. This work presents a simulation method to directly study the equilibrium of multiple states. This method constructs a virtual mixture of multiple states (VMMS) to sample the conformational space of all chemical states simultaneously. The VMMS system consists of multiple subsystems, one for each state. The subsystem contains a solute and a solvent environment. The solute molecules in all subsystems share the same conformation but have their own solvent environments. Transition between states is implicated by the change of their molar fractions. Simulation of a VMMS system allows efficient calculation of relative free energies of all states, which in turn determine their equilibrium molar fractions. For systems with a large number of state transition sites, an implicit site approximation is introduced to minimize the cost of simulation. A direct application of the VMMS method is for constant pH simulation to study protonation equilibrium. Applying the VMMS method to a heptapeptide of 3 ionizable residues, we calculated the pKas of those residues both with all explicit states and with implicit sites and obtained consistent results. For mouse epidermal growth factor of 9 ionizable groups, our VMMS simulations with implicit sites produced pKas of all 9 ionizable groups and the results agree qualitatively with NMR measurement. This example demonstrates the VMMS method can be applied to systems of a large number of ionizable groups and the computational cost scales linearly with the number of ionizable groups. For one of the most challenging systems in constant pH calculation, SNase Δ+PHS/V66K, our VMMS simulation shows that it is the state-dependent water penetration that causes the large deviation in lysine66’s pKa. PMID:26506245

  14. A Virtual Mixture Approach to the Study of Multistate Equilibrium: Application to Constant pH Simulation in Explicit Water.

    PubMed

    Wu, Xiongwu; Brooks, Bernard R

    2015-10-01

    Chemical and thermodynamic equilibrium of multiple states is a fundamental phenomenon in biology systems and has been the focus of many experimental and computational studies. This work presents a simulation method to directly study the equilibrium of multiple states. This method constructs a virtual mixture of multiple states (VMMS) to sample the conformational space of all chemical states simultaneously. The VMMS system consists of multiple subsystems, one for each state. The subsystem contains a solute and a solvent environment. The solute molecules in all subsystems share the same conformation but have their own solvent environments. Transition between states is implicated by the change of their molar fractions. Simulation of a VMMS system allows efficient calculation of relative free energies of all states, which in turn determine their equilibrium molar fractions. For systems with a large number of state transition sites, an implicit site approximation is introduced to minimize the cost of simulation. A direct application of the VMMS method is for constant pH simulation to study protonation equilibrium. Applying the VMMS method to a heptapeptide of 3 ionizable residues, we calculated the pKas of those residues both with all explicit states and with implicit sites and obtained consistent results. For mouse epidermal growth factor of 9 ionizable groups, our VMMS simulations with implicit sites produced pKas of all 9 ionizable groups and the results agree qualitatively with NMR measurement. This example demonstrates the VMMS method can be applied to systems of a large number of ionizable groups and the computational cost scales linearly with the number of ionizable groups. For one of the most challenging systems in constant pH calculation, SNase Δ+PHS/V66K, our VMMS simulation shows that it is the state-dependent water penetration that causes the large deviation in lysine66's pKa.

  15. All-Atom Continuous Constant pH Molecular Dynamics With Particle Mesh Ewald and Titratable Water.

    PubMed

    Huang, Yandong; Chen, Wei; Wallace, Jason A; Shen, Jana

    2016-11-08

    Development of a pH stat to properly control solution pH in biomolecular simulations has been a long-standing goal in the community. Toward this goal recent years have witnessed the emergence of the so-called constant pH molecular dynamics methods. However, the accuracy and generality of these methods have been hampered by the use of implicit-solvent models or truncation-based electrostatic schemes. Here we report the implementation of the particle mesh Ewald (PME) scheme into the all-atom continuous constant pH molecular dynamics (CpHMD) method, enabling CpHMD to be performed with a standard MD engine at a fractional added computational cost. We demonstrate the performance using pH replica-exchange CpHMD simulations with titratable water for a stringent test set of proteins, HP36, BBL, HEWL, and SNase. With the sampling time of 10 ns per replica, most pKa's are converged, yielding the average absolute and root-mean-square deviations of 0.61 and 0.77, respectively, from experiment. Linear regression of the calculated vs experimental pKa shifts gives a correlation coefficient of 0.79, a slope of 1, and an intercept near 0. Analysis reveals inadequate sampling of structure relaxation accompanying a protonation-state switch as a major source of the remaining errors, which are reduced as simulation prolongs. These data suggest PME-based CpHMD can be used as a general tool for pH-controlled simulations of macromolecular systems in various environments, enabling atomic insights into pH-dependent phenomena involving not only soluble proteins but also transmembrane proteins, nucleic acids, surfactants, and polysaccharides.

  16. Predicting sub-grid variability of soil water content from basic soil information

    NASA Astrophysics Data System (ADS)

    Qu, Wei; Bogena, Heye; Huisman, Johan Alexander; Vanderborght, Jan; Schuh, Max; Priesack, Eckart; Vereecken, Harry

    2015-04-01

    Knowledge of unresolved soil water content variability within model grid cells (i.e. sub-grid variability) is important for accurate predictions of land-surface energy and hydrologic fluxes. Here, we derived a closed-form expression to describe how soil water content variability depends on mean soil water content using stochastic analysis of 1D unsaturated gravitational flow based on the van Genuchten-Mualem (VGM) model. A sensitivity analysis of this closed-form expression showed that the n parameter strongly influenced both the shape and magnitude of the maximum of this relationship. In a next step, the closed-form expression was used to predict soil water content variability for eight datasets with varying soil texture using VGM parameters obtained from pedotransfer functions that rely on readily available soil information. Generally, there was good agreement between observed and predicted soil water content variability despite the obvious simplifications that were used to derive the closed-form expression (e.g. gravity flow in dry soils). A simplified closed-form expression that neglected the effect of pressure head fluctuations showed that the good performance in the dry soil range is related to the dominant role of the variability in MVG parameters determining water retention as compared to the effect of water flow. Furthermore, the novel closed-form expression was successfully used to inversely estimate the variability of hydraulic properties from observed data on soil water content variability from several test sites in Germany, China and Australia.

  17. QTL mapping of protein content and seed characteristics under water-stress conditions in sunflower.

    PubMed

    Ebrahimi, A; Maury, P; Berger, M; Calmon, A; Grieu, P; Sarrafi, A

    2009-05-01

    The purpose of this study was to identify genomic regions controlling seed protein content, kernel and hull weights, and seed density in water-stress conditions in sunflower (Helianthus annuus L.). The experiments consisted of a split-plot design (water treatment and recombinant inbred lines) with three blocks in two environments (greenhouse and field). High significant variation was observed between genotypes for all traits as well as for water treatment x genotype interaction. Several specific and nonspecific QTLs were detected for all traits under well-watered and water-stress conditions. Two SSR markers, ORS671_2 and HA2714, linked to protein content were identified that have no interaction with water treatments in greenhouse conditions. We also detected the E35M60_4 marker associated with kernel weight that had no interaction with water treatments. A specific QTL for protein content was detected with important phenotypic variance (17%) under water-stress conditions. Overlapping QTLs for protein content and seed density were identified in linkage group 15. This region probably has a peliotropic effect on protein content and seed density. QTLs for protein content colocated with grain weight traits were also identified.

  18. Arsenic content in ground and canal waters of Punjab, North-West India.

    PubMed

    Hundal, H S; Singh, Kuldip; Singh, Dhanwinder

    2009-07-01

    Groundwater is the primary source of drinking water for more than 95% of the population in Punjab. The world health organization and US Environment Protection Agency recently established a new maximum contaminant level of 10 ppb for arsenic in drinking water. The arsenic concentration of deep water tube wells located in Amritsar city used for domestic supply for urban population ranged from 3.8 to 19.1 ppb with mean value of 9.8 ppb. Arsenic content in hand pump water varied from 9 to 85 ppb with a mean value of 29.5 ppb. According to the safe limit of As, 54% and 97%, water samples collected from deep water tube wells and hand pumps, respectively, were not fit for human consumption. Arsenic content in canal water varied from 0.3 to 8.8 ppb with a mean value of 2.89 ppb. Canal water has got higher oxidation potential followed by deep tube well and hand pump water. The present study suggests the regular monitoring of arsenic content in deep tube well and shallow hand pump waters by water testing laboratories. The consumption of water having elevated concentration of As above the safe limit must be discouraged. In south-western districts of Punjab, it recommends the use of canal water for drinking purposes and domestic use by rural and urban populations than ground water sources.

  19. Temporal stability analysis of surface soil water content on two karst hillslopes in southwest China.

    PubMed

    Wang, Sheng; Chen, Hong Song; Fu, Zhiyong; Wang, Kelin

    2016-12-01

    Knowledge of the temporal variability of soil water content (SWC) at the hillslope scale is essential for guiding rehabilitation strategies and for optimizing water resource management in the karst region of southwest China. This study aimed to use temporal stability analysis to upscale point-scale measurements to represent mean areal SWC on two typical karst hillslopes. Based on a grid sampling scheme (10 m × 10 m) applied to two 90 m × 120 m plots located on two hillslops, the SWC at a depth of 0-16 cm was measured 11-12 times across 259 sampling points, using time domain reflectometry (TDR) from April 2011 to October 2012. Soil texture, bulk density (BD), saturated hydraulic conductivity (K s ), organic carbon (SOC), rock fragment content (RFC), and site elevation (SE) were also measured at these locations. Results showed the hillslope with more shrub cover was wetter than the hillslope with mixed grass-shrub cover. This difference was related to the differences in soil texture, soil hydraulic permeability, and topography. Through a comparison of values obtained with the Spearman correlation coefficient (r s ), standard deviation of mean relative difference (SDRD), and mean absolute bias error (MABE), we inferred that there is a higher degree of temporal stability for SWC in wet conditions than in drier conditions on the two hillslopes. Based on the values of the index of temporal stability (ITS), which combine the mean relative difference (MRD) and SDRD, the two locations were determined to be representative of mean SWC on both hillslopes. Moreover, these locations captured changes in mean SWC (NSCE = 0.69, and 0.65, and RMSE = 1.96, and 1.96 %, respectively). This demonstrates the feasibility of using the temporal stability of SWC to acquire mean SWC on karst hillslopes of southwestern China. The indirect method, which estimates mean SWC by considering the offset between the mean and the measurement value at a time-stable location, predicted mean SWC (NSCE

  20. Hydrogen production from high moisture content biomass in supercritical water

    SciTech Connect

    Antal, M.J. Jr.; Xu, X.

    1998-08-01

    By mixing wood sawdust with a corn starch gel, a viscous paste can be produced that is easily delivered to a supercritical flow reactor by means of a cement pump. Mixtures of about 10 wt% wood sawdust with 3.65 wt% starch are employed in this work, which the authors estimate to cost about $0.043 per lb. Significant reductions in feed cost can be achieved by increasing the wood sawdust loading, but such an increase may require a more complex pump. When this feed is rapidly heated in a tubular flow reactor at pressures above the critical pressure of water (22 MPa), the sawdust paste vaporizes without the formation of char. A packed bed of carbon catalyst in the reactor operating at about 650 C causes the tarry vapors to react with water, producing hydrogen, carbon dioxide, and some methane with a trace of carbon monoxide. The temperature and history of the reactor`s wall influence the hydrogen-methane product equilibrium by catalyzing the methane steam reforming reaction. The water effluent from the reactor is clean. Other biomass feedstocks, such as the waste product of biodiesel production, behave similarly. Unfortunately, sewage sludge does not evidence favorable gasification characteristics and is not a promising feedstock for supercritical water gasification.

  1. Understanding water content data in cottons equilibrated to moisture equilibrium

    USDA-ARS?s Scientific Manuscript database

    The accurate measurement of moisture in cottons conditioned to moisture equilibrium and understanding the data are prerequisites to the development of applications of the data. In this study, moisture is measured by Karl Fischer Titration, which is highly selective for water in cotton; the results ...

  2. Electrical Resistivity Imaging and Quantification of Water Content Distribution during Infiltration and Redistribution in Soils

    NASA Astrophysics Data System (ADS)

    Singha, K.; Mirus, B. B.; Nimmo, J. R.; Perkins, K.

    2006-12-01

    Controlled by precipitation, evapotranspiration, recharge, and soil-hydraulic properties, water content is difficult to measure extensively in heterogeneous, natural environments without disturbing the subsurface. Time-lapse electrical resistivity imaging (ERI) is a cost-effective, minimally invasive method for imaging changes in water content in the vadose zone. Quantifying the relation between resistivity and water content, however, is challenging due to 1) spatially variable resolution, 2) spatial variability in the properties that relate resistivity to water content, 3) possible variability of soil-water salinity, and 4) the need for introduction of auxiliary information to achieve a unique solution of the inverse problem. Although quantitative integration of ERI data into hydrogeologic studies is complicated by these problems, the ERI technique provides copious and spatially exhaustive soft data that would otherwise be unavailable in this heterogeneous environment, especially over the multi-meter scale. We developed a methodology for analyzing ERI measurements in terms of water content, and applied it to ERI data collected during infiltration/redistribution experiments conducted in two soil types in the Mojave National Preserve. One experiment was conducted in an active wash, the other in a highly developed Pleistocene soil. In both, changes in water content through time were estimated from ERI to a depth of approximately 1.5 m during and after ponded infiltration in a 1-m diameter ring. Approximately 40 snapshots over approximately one week along intersecting two-dimensional lines were collected through time for both experiments. To reduce ambiguities in our interpretation, we use numerical simulations of water and electrical flow to convert estimated resistivity to water content, calibrating for variations in resolution, spatially variable petrophysical properties, and fluid salinity on the relation between water content and estimated resistivity

  3. Water content in intraplate basalt magmas from the Longgang area, NE China

    NASA Astrophysics Data System (ADS)

    Mizobuchi, F.; Kuritani, T.; Yoshida, T.; Miyamoto, T.; Nagahashi, Y.; Taniguchi, H.

    2009-12-01

    In northeastern China, intraplate magmatism has been active, and Cenozoic basalts are widely distributed. Beneath the area, the subducted Pacific slab is stagnant in the mantle transition zone, and some previous studies have inferred that the magmatism may have been affected by fluid phases released from the stagnant slab. To test this hypothesis, it is important to know the water content in the source mantle. In this context, the water content in the intraplate magma was estimated using primitive scoria samples from the Longgang area, NE China. Because of the absence of glass inclusions in phenocrysts that enables direct measurement of water content, it was estimated by thermodynamic constraints. During ascent of water-bearing magmas, the water solubility tends to decrease, and water saturation is achieved at depth. Then, crystals can grow rapidly by an increase in the liquidus temperature resulting from water exsolution. Because the microlites in our samples can be regarded as such crystals, the water content in the magma in which the microlites occured was estimated by thermodynamic analyses using the compositions of the microlites and glass. In the calculations, thermodynamic solution models of e.g. Ghiorso&Sack(1995) were used. The calculated water content and the temperature of the magma were about 0.6 wt.% and 1110 degC, respectively. The water content is slightly higher than those of primitive intraplate magmas such as from Hawaii (0.4 wt.%, Wallace & Anderson,1998) and Iceland (0.1-0.4 wt.%, Nichols et al., 2002). Assuming that the degree of melting was 1-2%, the water content of the source asthenospheric mantle was 110-170 ppm. The magma temperature at 80-120 km depth (garnet stability field) was also estimated as 1160-1180 degC, assuming adiabatic ascent. Using the constraints obtained in this study, the effect of stagnant-slab-derived fluids on the magma generation will be evaluated as a future study.

  4. Water content and the conversion of phytochrome regulation of lettuce dormancy

    NASA Technical Reports Server (NTRS)

    Vertucci, C. W.; Vertucci, F. A.; Leopold, A. C.

    1987-01-01

    In an effort to determine which biological reactions can occur in relation to the water content of seeds, the regulation of lettuce seed dormancy by red and far red light was determined at various hydration levels. Far red light had an inhibiting effect on germination for seeds at all moisture contents from 4 to 32% water. Germination was progressively stimulated by red light as seed hydration increased from 8 to 15%, and reached a maximum at moisture contents above 18%. Red light was ineffective at moisture contents below 8%. Seeds that had been stimulated by red light and subsequently dried lost the enhanced germinability if stored at moisture contents above 8%. The contrast between the presumed photoconversion of phytochrome far red-absorbing (Pfr) to (Pr) occurring at any moisture content and the reverse reaction occurring only if the seed moisture content is greater than 8% may be explained on the basis of the existence of unstable intermediates in the Pr to Pfr conversion. Our results suggest that the initial photoreaction involved in phytochrome conversion is relatively independent of water content, while the subsequent partial reactions become increasingly facilitated as water content increases from 8 to 18%.

  5. Water content and the conversion of phytochrome regulation of lettuce dormancy

    NASA Technical Reports Server (NTRS)

    Vertucci, C. W.; Vertucci, F. A.; Leopold, A. C.

    1987-01-01

    In an effort to determine which biological reactions can occur in relation to the water content of seeds, the regulation of lettuce seed dormancy by red and far red light was determined at various hydration levels. Far red light had an inhibiting effect on germination for seeds at all moisture contents from 4 to 32% water. Germination was progressively stimulated by red light as seed hydration increased from 8 to 15%, and reached a maximum at moisture contents above 18%. Red light was ineffective at moisture contents below 8%. Seeds that had been stimulated by red light and subsequently dried lost the enhanced germinability if stored at moisture contents above 8%. The contrast between the presumed photoconversion of phytochrome far red-absorbing (Pfr) to (Pr) occurring at any moisture content and the reverse reaction occurring only if the seed moisture content is greater than 8% may be explained on the basis of the existence of unstable intermediates in the Pr to Pfr conversion. Our results suggest that the initial photoreaction involved in phytochrome conversion is relatively independent of water content, while the subsequent partial reactions become increasingly facilitated as water content increases from 8 to 18%.

  6. Monitoring of Water Content And Frozen State by using Millimeter Wave Absorption Features

    NASA Astrophysics Data System (ADS)

    Mizuno, Maya; Shindo, Kenji; Ogawa, Yuichi; Otani, Chiko; Kawase, Kodo

    In this research, we built an experimental setup for measuring the water content in plants and food, and for determining the water/ice state of a sample. The setup consists of a 35 GHz Gunn oscillator producing about 10 mW of output power, two horn antennas and a power meter. We have checked that the absorption of a leaf is directly proportional to its water content, and we could show how changes of the water content depend on photosynthesis, by intermittent illumination with a white fluorescent lamp. In another direction of research, we verified that the difference in the absorption coefficients for water and ice is significant, and we could discriminate and monitor the frozen state of water and food material. All these experiments demonstrate the possibility of applying millimeter waves to fields such as botany, agriculture, and food industry.

  7. Spatial and temporal mapping of water content across Nafion membranes under wetting and drying conditions.

    PubMed

    Zhang, Ziheng; Marble, Andrew E; MacMillan, Bryce; Promislow, Keith; Martin, Jonathan; Wang, Haijiang; Balcom, Bruce J

    2008-10-01

    Water transport and water management are fundamental to polymer electrolyte membrane fuel cell operation. Accurate measurements of water content within and across the Nafion layer are required to elucidate water transport behavior and validate existing numerical models. We report here a direct measurement of water content profiles across a Nafion layer under wetting and drying conditions, using a novel magnetic resonance imaging methodology developed for this purpose. This method, multi-echo double half k-space spin echo single point imaging, based on a pure phase encode spin echo, is designed for high resolution 1D depth imaging of thin film samples. The method generates high resolution (<8 microm) depth images with an SNR greater than 20, in an image acquisition time of less than 2 min. The high temporal resolution permits water content measurements in the transient states of wetting and drying, in addition to the steady state.

  8. Measurement of water content in polymer electrolyte membranes using high resolution neutron imaging

    SciTech Connect

    Spernjak, Dusan; Mukundan, Rangachary; Borup, Rodney L; Davey, John; Mukherjee, Partha P; Hussey, Daniel S; Jacobson, David

    2010-01-01

    Sufficient water content within a polymer electrolyte membrane (PEM) is necessary for adequate ionic conductivity. Membrane hydration is therefore a fundamental requirement for fuel cell operation. The hydration state of the membrane affects the water transport within, as both the diffusion coefficient and electro-osmotic drag depend on the water content. Membrane's water uptake is conventionally measured ex situ by weighing free-swelling samples equilibrated at controlled water activity. In the present study, water profiles in Nafion{reg_sign} membranes were measured using the high-resolution neutron imaging. The state-of-the-art, 10 {micro}m resolution neutron detector is capable of resolving water distributions across N1120, N1110 and N117 membranes. It provides a means to measure the water uptake and transport properties of fuel cell membranes in situ.

  9. A two-channel, tunable diode laser-based hygrometer for measurement of water vapor and cirrus cloud ice water content in the upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Thornberry, T. D.; Rollins, A. W.; Gao, R. S.; Watts, L. A.; Ciciora, S. J.; McLaughlin, R. J.; Fahey, D. W.

    2015-01-01

    The recently developed NOAA Water instrument is a two-channel, closed-path, tunable diode laser absorption spectrometer designed for the measurement of upper troposphere/lower stratosphere water vapor and enhanced total water (vapor + inertially enhanced condensed phase) from the NASA Global Hawk unmanned aircraft system (UAS) or other high-altitude research aircraft. The instrument utilizes wavelength-modulated spectroscopy with second harmonic detection near 2694 nm to achieve high precision with a 79 cm double-pass optical path. The detection cells are operated under constant temperature, pressure, and flow conditions to maintain a constant sensitivity to H2O independent of the ambient sampling environment. An onboard calibration system is used to perform periodic in situ calibrations to verify the stability of the instrument sensitivity during flight. For the water vapor channel, ambient air is sampled perpendicular to the flow past the aircraft in order to reject cloud particles, while the total water channel uses a heated, forward-facing inlet to sample both water vapor and cloud particles. The total water inlet operates subisokinetically, thereby inertially enhancing cloud particle number in the sample flow and affording increased cloud water content sensitivity. The NOAA Water instrument was flown for the first time during the second deployment of the Airborne Tropical TRopopause EXperiment (ATTREX) in February-March 2013 on the NASA Global Hawk UAS. The instrument demonstrated a typical in-flight precision (1 s, 1σ) of better than 0.17 parts per million (ppm, 10-6 mol mol-1), with an overall H2O vapor measurement uncertainty of 5% ± 0.23 ppm. The inertial enhancement for cirrus cloud particle sampling under ATTREX flight conditions ranged from 33 to 48 for ice particles larger than 8 μm in diameter, depending primarily on aircraft altitude. The resulting ice water content detection limit (2σ) was 0.023-0.013 ppm, corresponding to approximately 2 μg m

  10. Seasonal variation in vegetation water content estimated from proximal sensing and MODIS time series in a Mediterranean Fluxnet site

    NASA Astrophysics Data System (ADS)

    Mendiguren, G.; Martín, M. P.; Nieto, H.; Pacheco-Labrador, J.; Jurdao, S.

    2015-04-01

    This study evaluates three different metrics of vegetation water content estimated from proximal sensing and MODIS satellite imagery: Fuel Moisture Content (FMC), Equivalent Water Thickness (EWT) and Canopy Water Content (CWC). Dry matter (Dm) and Leaf area Index (LAI) were also analyzed in order to connect FMC with EWT and EWT with CWC, respectively. This research took place in a Fluxnet site located in Mediterranean wooded grassland (dehesa) ecosystem in Las Majadas del Tietar (Spain). Results indicated that FMC and EWT showed lower spatial variation than CWC. The spatial variation within the MODIS pixel was not as critical as its temporal trend, so to capture better the variability, fewer plots should be sampled but more times. Due to the high seasonal Dm variability, a constant annual value would not work to predict EWT from FMC. Relative root mean square error (RRMSE) evaluated the performance of nine spectral indices to compute each variable. VARI provided the worst results in all cases. For proximal sensing, GEMI worked best for both FMC (RRMSE = 34.5%) and EWT (RRMSE = 27.43%) while NDII and GVMI performed best for CWC (RRMSE =30.27% and 31.58% respectively). For MODIS data, results were a bit better with EVI as the best predictor for FMC (RRMSE = 33.81%) and CWC (RRMSE = 27.56%) and GEMI for EWT (RRMSE = 24.6%). To explain these differences, proximal sensing measures only grasslands at nadir view angle, but MODIS includes also trees, their shades, and other artifacts at up to 20° view angle. CWC was better predicted than the other two water content variables, probably because CWC depends on LAI, which is highly correlated to the spectral indices. Finally, these empirical methods outperformed FMC and CWC products based on radiative transfer model inversion.

  11. A new method for measuring unfrozen water content of frozen soil based on soil resistivity

    NASA Astrophysics Data System (ADS)

    Tang, Liyun; Yang, Gengshe; Xi, Jiami; Jia, Hailiang; Qiu, Peiyong; Wang, Ke

    2017-04-01

    In the field of permafrost engineering, in order to determine the unfrozen water content of frozen soil in a more economical and quick way, a resistivity-based method is proposed to predict the unfrozen water content by building the relationship of resistivity (ρ), water content (θ) and temperature (T) through laboratory experiments. In the experiments, advanced Mile soil sample boxes are used to shape groups of soil samples with an initial water content of 5%, 10%, 15%, 20% and 25% separately. The experiment is composed of two parts. In the first part, oven drying method is used to dry the soil sample until the water content is less than 1%, and the resistivity of samples is continuously measured for each decrease of 0.5g water in soil samples; the relationship between water content (ρ) and resistivity (θ) at normal temperatures is established and expressed as a ρ-θ mode, which accords with power function. In the second part, the freezing method is used to freeze soil samples. When soil samples' temperature decreases from 0°C to -25°C, the resistivity of samples is continuously measured for each decrease of 0.1°C; the relationship between resistivity (ρ) and temperature (T) at minus degrees is established and expressed as a ρ-T mode, which accords with power function. The ρ-θ model at normal temperature is introduced to indirectly reflect the ρ-θu model at negative degree of temperature, which has been verified through a series of experiments with the NMR method. Combined with the ρ-T mode at minus degree of temperature, the relationship between unfrozen water content and temperature is deduced and established as θu-T model. By contrastive analysis, the accuracy to measure unfrozen water content with the resistivity-based method is validated by the NMR method, which is used to obtain the relationship between the unfrozen water contents and temperature. Based on the research results, the surface model related to resistivity, temperature and

  12. Seasonal variation in grass water content estimated from proximal sensing and MODIS time series in a Mediterranean Fluxnet site

    NASA Astrophysics Data System (ADS)

    Mendiguren, G.; Martín, M. Pilar; Nieto, H.; Pacheco-Labrador, J.; Jurdao, S.

    2015-09-01

    This study evaluates three different metrics of water content of an herbaceous cover in a Mediterranean wooded grassland (dehesa) ecosystem. Fuel moisture content (FMC), equivalent water thickness (EWT) and canopy water content (CWC) were estimated from proximal sensing and MODIS satellite imagery. Dry matter (Dm) and leaf area index (LAI) connect the three metrics and were also analyzed. Metrics were derived from field sampling of grass cover within a 500 m MODIS pixel. Hand-held hyperspectral measurements and MODIS images were simultaneously acquired and predictive empirical models were parametrized. Two methods of estimating FMC and CWC using different field protocols were tested in order to evaluate the consistency of the metrics and the relationships with the predictive empirical models. In addition, radiative transfer models (RTM) were used to produce estimates of CWC and FMC, which were compared with the empirical ones. Results revealed that, for all metrics spatial variability was significantly lower than temporal. Thus we concluded that experimental design should prioritize sampling frequency rather than sample size. Dm variability was high which demonstrates that a constant annual Dm value should not be used to predict EWT from FMC as other previous studies did. Relative root mean square error (RRMSE) evaluated the performance of nine spectral indices to compute each variable. Visible Atmospherically Resistant Index (VARI) provided the lowest explicative power in all cases. For proximal sensing, Global Environment Monitoring Index (GEMI) showed higher statistical relationships both for FMC (RRMSE = 34.5 %) and EWT (RRMSE = 27.43 %) while Normalized Difference Infrared Index (NDII) and Global Vegetation Monitoring Index (GVMI) for CWC (RRMSE = 30.27 % and 31.58 % respectively). When MODIS data were used, results showed an increase in R2 and Enhanced Vegetation Index (EVI) as the best predictor for FMC (RRMSE = 33.81 %) and CWC (RRMSE = 27.56 %) and GEMI

  13. Monitoring Changes in Soil Water Content Using Subsurface Displacement

    NASA Astrophysics Data System (ADS)

    Thrash, C. J.; Miller, S.; Murdoch, L. C.; Germanovich, L. N.; Gates, J. B.; Volkmer, A.; Weinburg, A.

    2013-12-01

    Closing the water balance is important in many research and water resource applications, but it can be difficult to accomplish due to a variety of factors. A new technique that measures vertical displacement of soil in order to estimate the change in mass of water stored in overlying material is being developed. The measurement technique uses an extensometer that functions as a lysimeter, and we refer to the technique as Displacement Extensometry for Lysimetric Terrain Analysis (DELTA). DELTA extensometers are 2-m-long devices deployed by creating a friction fit with intact soil below a cased borehole. The instrument measures small displacements (better than 10 nm resolution) in response to changes of mass in the overlying soil, or other factors. The instrument averages over a region that scales with the depth of installation (the radius of influence is approximately 2x the depth). The spatial averaging of this instrument extends over regions representative of agricultural fields, hydrologic model grid blocks, and small watersheds. Five DELTA extensometers have been deployed at a field site near Clemson, SC at depths of 3, 6, and 9 m within saprolite derived from biotite gneiss. Barometric pressure, precipitation, and soil moisture are being measured along with displacement. Signals from the co-located extensometers are remarkably similar, demonstrating reproducibility of the technique. Rainfall causes soil compression, and at 6 m depth there is approximately 200 nm of compression per 1 mm of rainfall. There is gradual expansion, which ranges from 0.15 to 1.75 μm/day, following rainfall. The gradual unloading of the soil is interpreted as water loss due to evapotranspiration. Superimposed on the signal are diurnal fluctuations of 0.5 to 1 μm, which correlate to changes in barometric pressure. Four DELTA extensometers were recently deployed in hard, clayey sediments at two field locations south of Amarillo, TX. The instruments will compliment current research on

  14. Identifying the role of flow rate and water content in colloid transport in unsaturated porous media

    NASA Astrophysics Data System (ADS)

    Knappenberger, T.; Flury, M.; Mattson, E. D.; Harsh, J.; Zang, F.; Gee, G.; Lichtner, P.

    2012-04-01

    Colloid transport in unsaturated soils and sediments is strongly affected by the presence of the air-water interface. The air-water interface is related to the water content, and as such, water content which plays a dominant role controlling colloid transport. The goal of our research is to elucidate the combined effects of water content and flow rates on colloid transport in unsaturated porous media. We conducted colloid transport experiments under different water contents and flow rates in sand columns containing silica sand with sizes ranging from 250 to 425 micrometers. Two different carboxylate-modified polystyrene colloids (26 and 200 nm diameter) were introduced to unsaturated columns under steady-state flow. The solution chemistry was chosen so that colloid transport occurred under unfavorable attachment conditions. By using a geocentrifuge, Flow flow rate and water content were varied independently in our experiments, which under normal conditions cannot be varied independently,is not possible were varied in our experiments independently by using a geocentrifuge. This unique experimental setup allowed us to run a series of colloid transport experiments at different water contents (effective saturation of 1.0, 0.6, 0.32, 0.19) but identical pore water velocity (10.6 cm/min). In general, decreasing water content led to increased colloid retention inside the columns. A portion of the retained colloids could be released by changing the solution chemistry, indicating that colloids had been retained in the secondary energy minimum. A DLVO analysis supports this assumption. We attribute unrecovered colloids in the outflow to the presence of flow stagnation zones. Overall the retention of the 26 nm colloids was stronger than the retention of the 220 nm colloids. Calculations of hydrodynamic forces suggest that the higher drag forces acting on the 220 nm colloids compared to the 26 nm colloids are responsible for the differences in retention.

  15. [Discussion on hyperspectral index for the estimation of cotton canopy water content].

    PubMed

    Wang, Qiang; Yi, Qiu-Xiang; Bao, An-Ming; Zhao, Jin

    2013-02-01

    Proper vegetation indices have decisive influences on the precision of hyperspectral estimation models for surface parameters. In the present paper, in order to find the proper hyperspectral indices for cotton canopy water content estimation, two water parameters for cotton canopy water content (EWT(canopy), equivalent water thickness; VWC, vegetation water content) and corresponding hyperspectra data were analyzed. A rigorous search procedure was used to determine the best index predictors of cotton canopy water. In the procedure, all possible ratio indices and normalized difference indices were derived from the canopy hyperspectra, involving all the two-band combinations between 350 nm and 2500 nm. Then the correlation between two water parameters and all combination indices were analyzed, and the best indices which produced maximum correlation coefficients were determined. Finally, the indices were compared with the published water indices for their performances in estimation of cotton canopy water content. The results showed that for the estimation of EWT(canopy), the new developed ratio index R1 475/R1 424 and normalized difference index (R1 475 -R1 424)/(R1 475 + R1 424) was the most proper one, and the correlation coefficient of the estimated and measured EWT(canopy) reached 0.849. For the estimation of VWC, the performance of published index was better than new developed index, the best suitable water indices for VWC estimation were (R835 - R1 650)/(R835 + R1 650), and the correlation coefficient of the estimated and measured VWC was 0.849.

  16. Modeling and monitoring cyclic and linear volatile methylsiloxanes in a wastewater treatment plant using constant water level sequencing batch reactors.

    PubMed

    Wang, De-Gao; Du, Juan; Pei, Wei; Liu, Yongjun; Guo, Mingxing

    2015-04-15

    The fate of cyclic and linear volatile methylsiloxanes (VMSs) was evaluated in a wastewater treatment plant (WWTP) using constant water level sequencing batch reactors from Dalian, China. Influent, effluent, and sewage sludge samples were collected for seven consecutive days. The mean concentrations of cyclic VMSs (cVMSs) in influent and effluent samples are 1.05 μg L(-1) and 0.343 μg L(-1); the total removal efficiency of VMSs is >60%. Linear VMS (lVMS) concentration is under the quantification limitation in aquatic samples but is found in sludge samples with a value of 90 μg kg(-1). High solid-water partition coefficients result in high VMS concentrations in sludge with the mean value of 5030 μg kg(-1). No significant differences of the daily mass flows are found when comparing the concentration during the weekend and during working days. The estimated mass load of total cVMSs is 194 mg d(-1)1000 inhabitants(-1) derived for the population. A mass balance model of the WWTP was developed and derived to simulate the fate of cVMSs. The removal by sorption on sludge increases, and the volatilization decreases with increasing hydrophobicity and decreasing volatility for cVMSs. Sensitivity analysis shows that the total suspended solid concentration in the effluent, mixed liquor suspended solid concentration, the sewage sludge flow rate, and the influent flow rate are the most influential parameters on the mass distribution of cVMSs in this WWTP.

  17. [Fluoride content in potable water and drinks. Connection with dental caries prevention and dental fluorosis].

    PubMed

    Borinskiĭ, Iu N; Rumiantsev, V A; Borinskaia, E Iu; Beliaev, V V

    2009-01-01

    Content of fluoride by ion selective electrode in potable water (municipal water supply, bottled, from draw-wells and springs), in juices of industrial and compotes of domestic preparation, in drinks of various grades of the tea made by water with unequal contents of fluorine was analyzed. Fluoride entered organism of the population in non-control mode more often in minimum quantities that explained, in certain measures a wide caries incidence. Granting of the information upon concentration of fluorides in potable water, juices and drinks used by population would allow people to adjust this microelement intake in the organism with the purpose of preventing of dental caries and fluorosis.

  18. Wheat streak mosaic: A classic case of plant disease impact on soil water content and crop water-use efficiency

    USDA-ARS?s Scientific Manuscript database

    In this article, we describe the relationship between wheat streak mosaic (WSM) severity and soil water content as a prime example of the effect of a plant disease on soil water status and its implications for irrigated agriculture. The present study was part of a larger investigation which included...

  19. Wheat Streak Mosaic: A classic case of plant disease impact on soil water content and crop water-use efficiency

    USDA-ARS?s Scientific Manuscript database

    In this article, we describe the relationship between wheat streak mosaic (WSM) severity and soil water content as a prime example of the effect of a plant disease on soil water status and its implications for irrigated agriculture. The present study was part of a larger investigation which included...

  20. Suitability of single tissue dielectric constant measurements to assess local tissue water in normal and lymphedematous skin.

    PubMed

    Mayrovitz, Harvey N; Davey, Suzanne; Shapiro, Elizabeth

    2009-04-01

    Previous reports described the use of average tissue dielectric constant (TDC) measurements to assess local tissue water and its change. Our goal was to determine if a single TDC measurement could be used in place of the average of multiple measurements. The comparison criteria used to test this was the extent to which single and averaged measurements yielded similar TDC values in both normal and lymphedematous tissue. Measurements were made in two groups of women; a control group (n = 20) and a group with unilateral arm lymphedema (n = 10). In the control group, TDC was measured to multiple depths (0.5-5.0 mm) on both ventral forearms and to a depth of 2.5 mm on the lateral thorax on both body sides. In the lymphedematous group, TDC was measured on both ventral forearms to a depth of 2.5 mm. Results showed that the 95% confidence interval for differences between single and averaged TDC values was less than +/-1 TDC unit and that the limits of agreement between methods was less than +/-2.5 TDC units (+/-6.5%) for each condition, site and depth measured. This finding suggests that where this level of agreement is acceptable suitable clinical assessments can be made using a single TDC measurement.

  1. The relationship between water content and Al-content in the MTZ and the lower mantle minerals

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Yabuki, T.; Yurimoto, H.

    2011-12-01

    Water is an important volatile component in the Earth mantle, and many high pressure experiments have been conducted so far to determine the stability region of both dense hydrous magnesium silicate (DHMS) and nominally anhydrous minerals with some water. Al3+ is supposed to be coupled with H+ by a substitution with Mg2+, Si4+ or Mg2+ + Si4+. To clarify the degree of the substitution, the water contents and the chemical compositions of Al-bearing minerals in the mantle transition zone and the lower mantle were determined in the systems pyrope - enstatite with H2O of 11.3 wt% and 18.7 wt% at pressures of 20-26 GPa and temperatures of 1473-1873 K, corresponding to the mantle transition zone (MTZ) and the lower mantle. High pressure experiments were conducted by Kawai-type high pressure apparatuses at Ehime University. Starting materials were the mixtures of MgO and SiO2 oxides, and Mg(OH)2 and Al(OH)3 hydroxides with appropriate proportions. We selected the molar ratios of Mg:Si:Al:H = 3:3:1:9 and 3:3:1:5, which H2O contents were 18.7 and 11.3 wt%, respectively, as the starting compositions. The sample was sealed by an AuPd capsule. The recovered charges were polished, and identified by micro-RAMAN spectroscopy, and the chemical compositions for Mg, Si and Al were measured by SEM-EDS at Ehime University. The water contents were measured by secondary ion mass spectrometry (SIMS) at Hokkaido University. In all experimental conditions, hydrous liquid was observed. At 20 GPa, garnet and stishovite was observed, but above 22.5 GPa, phase D was observed instead of garnet in the wide range of the present experimental conditions. At 26 GPa and 1873 K, perovskite was observed. The present phase D included a large amount of Al2O3 (~12-21 wt%), and the Mg/Si molar ratios were ~0.7-0.8. The Al content increased and the Mg/Si ratio decreased, with increasing temperature. Frost and Fei (1998) first reported phase D in the MgO-SiO2-H2O system. Our Mg/Si ratio is ~0.1 larger than

  2. Results and Conclusions from the NASA Isokinetic Total Water Content Probe 2009 IRT Test

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew; Brinker, David

    2010-01-01

    The NASA Glenn Research Center has developed and tested a Total Water Content Isokinetic Sampling Probe. Since, by its nature, it is not sensitive to cloud water particle phase nor size, it is particularly attractive to support super-cooled large droplet and high ice water content aircraft icing studies. The instrument comprises the Sampling Probe, Sample Flow Control, and Water Vapor Measurement subsystems. Results and conclusions are presented from probe tests in the NASA Glenn Icing Research Tunnel (IRT) during January and February 2009. The use of reference probe heat and the control of air pressure in the water vapor measurement subsystem are discussed. Several run-time error sources were found to produce identifiable signatures that are presented and discussed. Some of the differences between measured Isokinetic Total Water Content Probe and IRT calibration seems to be caused by tunnel humidification and moisture/ice crystal blow around. Droplet size, airspeed, and liquid water content effects also appear to be present in the IRT calibration. Based upon test results, the authors provide recommendations for future Isokinetic Total Water Content Probe development.

  3. Magnetic resonance imaging (MRI) study of the water content and transport in rat lenses.

    PubMed

    Dobretsov, Egor A; Snytnikova, Olga A; Koptyug, Igor V; Kaptein, Robert; Tsentalovich, Yuri P

    2013-08-01

    NMR micro-imaging technique has been used for the measurement of the water content distribution in lenses of senescence-accelerated OXYS rats and age-matched Wistar rats, as well as for the study of water and phosphate transport in rat lenses. The water content in the lens cortex is significantly higher than in the nucleus; the spatial gradient of the water content becomes steeper with age. No difference in the water content distribution has been found between Wistar and OXYS rat lenses of matching ages, although cataract onset in the OXYS rat lens occurs much earlier due to the enhanced generation of reactive oxygen species associated with oxidative stress. This finding implies that cataract development does not lead to significant changes in water content distribution inside the lens. The water transport in rat lenses slows down with age, and in OXYS lenses it is somewhat faster than in lenses of Wistar rats, probably due to the compensatory response to oxidative stress. The application of (31)P MRI for the monitoring of phosphate penetration into a lens has been performed for the first time. It is found that phosphate transport in a lens is significantly slower than that of water.

  4. Phase transitions of pea starch over a wide range of water content.

    PubMed

    Wang, Shujun; Copeland, Les

    2012-06-27

    The phase transitions of pea starch over a wide range of water content were investigated by differential scanning calorimetry (DSC). Swelling of starch granules increased progressively with increasing water content. The main endotherm G broadened progressively with increasing water content up to 94.5 wt % (water:starch ratio 15:1), above which it became too broad to define. The corresponding peak and conclusion temperatures and enthalpy change increased with increasing water content. Scanning electron microscopy (SEM) showed that, at a water:starch ratio of 2:1 (water content of 70.7 wt %), starch granules only swelled partially with discernible granular contours still clearly evident. The results of swelling power tests and SEM images revealed that the endotherm G obtained at a water:starch ratio of 2:1 represented only partial swelling of starch granules. The transition from a narrow to broad endotherm G was interpreted to reflect the thermal transition behavior progressing from limited swelling to maximum swelling and then partial dissolution and leaching of starch polymers from the granules.

  5. Fluoride content of still bottled waters available in the North-East of England, UK.

    PubMed

    Zohouri, F V; Maguire, A; Moynihan, P J

    2003-11-08

    The aims of this study were to measure the fluoride content of still bottled waters on sale in the UK and to estimate and compare the fluoride intake from tap and bottled water for British children. Three bottles of 25 commercial brands of bottled water were purchased from supermarkets, grocery stores and health shops in the North-East of England. All samples were still spring, mineral or distilled waters, sold in plastic bottles. The fluoride content of all samples was determined, in duplicate, using a Fluoride Ion Selective Electrode. The mean (+/- SD) fluoride content of the bottled waters was 0.08 (+/- 0.08) mg L(-1) with a range from 0.01-0.37 mg L(-1) which is below the accepted standard for optimally fluoridated water. The mean fluoride intake for 4-18-year-olds when the source of water intake is solely fluoridated tap water was estimated to be 0.26 mg F per day; compared with 0.16 mg F per day, when a combination of tap and bottled water is consumed. Bottled water, from those sampled, is unlikely to make an important contribution to total fluoride intake in British diets. Consumption of bottled water containing a negligible amount of fluoride in preference to fluoridated tap water might result in less than optimal fluoride ingestion in young people.

  6. What is the Water (OH) Content of the E Asteroids?

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.

    2005-01-01

    Attempts to match the E asteroids with enstatite-rich meteorites universally conclude that the aubrites or enstatite chondrites are natural candidates, and accordingly conclude that E asteroids as a class are very water-poor. Accordingly, the highly reduced nature of typical enstatite-rich meteorites suggests that aqueous alteration was an improbable process on any E asteroid. However, there are spectroscopic observations of several E-class asteroids that suggest the presence there of hydrated phases. Examination of the Kaidun meteorite reveals the true situation.

  7. Current Status of our Understanding of the Water Content in the Mantle Transition Zone

    NASA Astrophysics Data System (ADS)

    Karato, S.; Dai, L.

    2008-12-01

    The water content of the mantle transition zone is a key factor that controls (or reflects) the nature of materials circulation in Earth. Although the maximum amount of water in the transition zone is well constrained by the experimental data on the solubility of water in the constituent minerals, actual water content in the mantle transition zone is highly controversial, and the published results range from almost dry to nearly water-saturated transition zone. In this presentation, we will review various methods to infer the water content in the transition zone including those using (i) seismological observations and (ii) electrical conductivity. Seismological observations used to infer water content include (i) the thickness-velocity anomalies correlation, (ii) the sharpness of the 410-km boundary and (iii) the seismic wave velocities. Limitations of this approach are that the direct influence of water on seismic wave velocities is appreciable only for large water contents (1 % or more) and the physical processes to control the sharpness of the 410-km are not unique. In contrast, the physical processes by which water (hydrogen) affects the electrical conductivity is well understood and the influence of water on electrical conductivity is large even for a relatively small water content. Therefore if the electrical conductivity in the mantle transition zone is known, and temperature is constrained within a certain range, the water content in the transition zone can be estimated from the comparison of laboratory data on electrical conductivity with geophysically determined electrical conductivity in the transition zone. However, there are a few technical details that one must pay attention to in order to obtain robust results on the influence of water on electrical conductivity. (i) Electrical conductivity must be determined from the measured impedance for a broad range of frequencies to eliminate the influence of charge accumulation (at electrodes and/or grain

  8. Estimating water content in an active landfill with the aid of GPR.

    PubMed

    Yochim, April; Zytner, Richard G; McBean, Edward A; Endres, Anthony L

    2013-10-01

    Landfill gas (LFG) receives a great deal of attention due to both negative and positive environmental impacts, global warming and a green energy source, respectively. However, predicting the quantity of LFG generated at a given landfill, whether active or closed is difficult due to the heterogeneities present in waste, and the lack of accurate in situ waste parameters like water content. Accordingly, ground penetrating radar (GPR) was evaluated as a tool for estimating in situ water content. Due to the large degree of subsurface heterogeneity and the electrically conductive clay cap covering landfills, both of which affect the transmission of the electromagnetic pulses, there is much scepticism concerning the use of GPR to quantify in situ water content within a municipal landfill. Two landfills were studied. The first landfill was used to develop the measurement protocols, while the second landfill provided a means of confirming these protocols. GPR measurements were initially completed using the surface GPR approach, but the lack of success led to the use of borehole (BH) GPR. Both zero offset profiling (ZOP) and multiple offset gathers (MOG) modes were tried, with the results indicating that BH GPR using the ZOP mode is the most simple and efficient method to measure in situ water content. The best results were obtained at a separation distance of 2m, where higher the water content, smaller the effective separation distance. However, an increase in water content did appear to increase the accuracy of the GPR measurements. For the effective separation distance of 2m at both landfills, the difference between GPR and lab measured water contents were reasonable at 33.9% for the drier landfill and 18.1% for the wetter landfill. Infiltration experiments also showed the potential to measure small increases in water content.

  9. The use of a permanent magnet for water content measurements ofwood chips

    SciTech Connect

    Barale, P.J.; Fong, C.G.; Green, M.A.; Luft, P.A.; McInturff,A.D.; Reimer, J.A.; Yahnke, M.

    2001-09-20

    The Lawrence Berkeley National Laboratory has developed a device that measures the water content of wood chips, pulp and brown stock for the paper industry. This device employs a permanent magnet as the central part of a NMR measurement system. This report describes the magnet and the NMR measurement system. The results of water content measurements in wood chips in a magnetic field of 0.47 T are presented.

  10. Magmatic water contents determined through clinopyroxene: Examples from the Western Canary Islands, Spain

    NASA Astrophysics Data System (ADS)

    Weis, Franz A.; Skogby, Henrik; Troll, Valentin R.; Deegan, Frances M.; Dahren, Börje

    2015-07-01

    Water is a key parameter in magma genesis, magma evolution, and resulting eruption styles, because it controls the density, the viscosity, as well as the melting and crystallization behavior of a melt. The parental water content of a magma is usually measured through melt inclusions in minerals such as olivine, a method which may be hampered, however, by the lack of melt inclusions suitable for analysis, or postentrapment changes in their water content. An alternative way to reconstruct the water content of a magma is to use nominally anhydrous minerals (NAMs), such as pyroxene, which take up low concentrations of hydrogen as a function of the magma's water content. During magma degassing and eruption, however, NAMs may dehydrate. We therefore tested a method to reconstruct the water contents of dehydrated clinopyroxene phenocrysts from the Western Canary islands (n = 28) through rehydration experiments followed by infrared and Mössbauer spectroscopy. Employing currently available crystal/melt partitioning data, the results of the experiments were used to calculate parental water contents of 0.71 ± 0.07 to 1.49 ± 0.15 wt % H2O for Western Canary magmas during clinopyroxene crystallization at upper mantle conditions. This H2O range is in agreement with calculated water contents using plagioclase-liquid-hygrometry, and with previously published data for mafic lavas from the Canary Islands and comparable ocean island systems elsewhere. Utilizing NAMs in combination with hydrogen treatment can therefore serve as a proxy for pre-eruptive H2O contents, which we anticipate becoming a useful method applicable to mafic rocks where pyroxene is the main phenocryst phase.

  11. Effect of water content and organic carbon on remote sensing of crop residue cover

    NASA Astrophysics Data System (ADS)

    Serbin, G.; Hunt, E. R., Jr.; Daughtry, C. S. T.; McCarty, G. W.; Brown, D. J.; Doraiswamy, P. C.

    2009-04-01

    Crop residue cover is an important indicator of tillage method. Remote sensing of crop residue cover is an attractive and efficient method when compared with traditional ground-based methods, e.g., the line-point transect or windshield survey. A number of spectral indices have been devised for residue cover estimation. Of these, the most effective are those in the shortwave infrared portion of the spectrum, situated between 1950 and 2500 nm. These indices include the hyperspectral Cellulose Absorption Index (CAI), and advanced multispectral indices, i.e., the Lignin-Cellulose Absorption (LCA) index and the Shortwave Infrared Normalized Difference Residue Index (SINDRI), which were devised for the NASA Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor. Spectra of numerous soils from U.S. Corn Belt (Indiana and Iowa) were acquired under wetness conditions varying from saturation to oven-dry conditions. The behavior of soil reflectance with water content was also dependent on the soil organic carbon content (SOC) of the soils, and the location of the spectral bands relative to significant water absorptions. High-SOC soils showed the least change in spectral index values with increase in soil water content. Low-SOC soils, on the other hand, showed measurable difference. For CAI, low-SOC soils show an initial decrease in index value followed by an increase, due to the way that water content affects CAI spectral bands. Crop residue CAI values decrease with water content. For LCA, water content increases decrease crop residue index values and increase them for soils, resulting in decreased contrast. SINDRI is also affected by SOC and water content. As such, spatial information on the distribution of surface soil water content and SOC, when used in a geographic information system (GIS), will improve the accuracy of remotely-sensed crop residue cover estimates.

  12. Rapid selection of a representative monitoring location of soil water content for irrigation scheduling using surface moisture-density gauge

    NASA Astrophysics Data System (ADS)

    Mubarak, Ibrahim; Janat, Mussadak; Makhlouf, Mohsen; Hamdan, Altayeb

    2016-10-01

    Establishing a representative monitoring location of soil water content is important for agricultural water management. One of the challenges is to develop a field protocol for determining such a location with minimum costs. In this paper, we use the concept of time stability in soil water content to examine whether using a short term monitoring period is sufficient to identify a representative site of soil water content and, therefore, irrigation scheduling. Surface moisture-density gauge was used as a means for measuring soil water content. Variations of soil water content in space and time were studied using geostatistical tools. Measuring soil water content was made at 30 locations as nodes of a 6×8 m grid, six times during the growing season. A representative location for average soil water content estimation was allocated at the beginning of a season, and thereafter it was validated. Results indicated that the spatial pattern of soil water content was strongly temporally stable, explained by the relationship between soil water content and fine soil texture. Two field surveys of soil water content, conducted before and after the 1st irrigation, could be sufficient to allocate a representative location of soil water content, and for adequate irrigation scheduling of the whole field. Surface moisture-density gauge was found to be efficient for characterising time stability of soil water content under irrigated field conditions.

  13. Effect of water content and heating temperature on thermal properties of brown rice batter

    NASA Astrophysics Data System (ADS)

    Aboukzail, Jehan; Abdullah, Aminah; Ghani, Maaruf Abd

    2015-09-01

    The objectives of this research were to assess the effect of water content in the formulation (60%,80%, 100%, 105%, 110%, 120% flour basis) on starch gelatinization of brown rice batter, and to identify the effects of heat treatment at 50°C, 60°C, 70°C, 80°C on starch gelatinization and degree of starch gelatinization of brown rice batter and wheat dough. At 60% water content, there was no gelatinization of brown rice batter, but the batter was gelatinized by increasing the water content to 80%. No significant differences in onset (To) peak (Tp) and endest (Tend) temperature when the water content increased from 80% to 120%; however, enthalpy (ΔH) decreased when water content grew up. Heat treatment of brown rice batter at 60% water content made brown rice batter gelatinized. Starch gelatinization temperature To, Tend and ΔH did not have significant differences when temperature of heat treatment increased from 50°C to 80°C while Tp increased significantly (p<0.05) at 80°C. However, heat treatment had more effect on wheat dough compared to brown rice batter.

  14. Magnetism in non-stoichiometric goethite of varying total water content and surface area

    NASA Astrophysics Data System (ADS)

    Barrero, C. A.; Betancur, J. D.; Greneche, J. M.; Goya, G. F.; Berquó, T. S.

    2006-02-01

    In this work, the magnetic properties of four non-stoichiometric goethites with varying total water content and surface area have been investigated. The samples were prepared using two different hydrothermal methods, deriving either from Fe(II) precursors or from Fe(III) precursors. The effects of both agitation during mixing solutions and drying time during synthesis upon the physical properties of the final products were also studied. The samples were characterized by XRD, TGA, BET, 57Fe Mössbauer spectrometry at 300 K, 77 K and 4.2 K, ZFC and FC curves, and magnetization curves. The goethites synthesized from the Fe(II) precursors result less crystalline, contain higher water content than those prepared from the Fe(III) precursor. In addition, ferrous precursor goethites exhibit superparamagnetic relaxation effects, while the ferric precursor goethites exhibit magnetic ordering of clusters. It is found that the stirring process during synthesis can affect the total water content and the magnetic behaviour of the goethites. Our results suggest that structural water content decreases the magnetic hyperfine field at 4.2 K. The adsorbed water content also affects this parameter as suggested by in situ annealing cycles of the goethites in a Mössbauer cryofurnace. Finally, we propose an unique 2-D phase diagram to describe all the magnetic properties of present goethites observed as a function of temperature, surface area (or particle size) and total water content.

  15. Effect of Water Content on Enthalpic Relaxations in Porcine Septal Cartilage

    PubMed Central

    Chae, Y.; Protsenko, D.; Lavernia, E. J.; Wong, B. J. F.

    2014-01-01

    Cartilage thermoforming is an emerging surgical technology which uses heat to accelerate stress relaxation in mechanically deformed tissue specimens. Heat induced shape change in cartilage is associated with complex thermo mechanical behavior of which the mechanisms are still a subject of debate. Differential scanning calorimetry (DSC) was used to characterize the threshold temperatures and enthalpies in cartilage as a function of water content. The DSC identified two enthalpic events in porcine nasal septal cartilage, which depend on the water content. The change in the water content of cartilage impacts the interactions between matrix macromolecules and water molecules, which may be associated with a bound-free water transformation (reversible process) and a denaturation of cartilage (irreversible process). PMID:25425960

  16. Effect of Water Content on Enthalpic Relaxations in Porcine Septal Cartilage.

    PubMed

    Chae, Y; Protsenko, D; Lavernia, E J; Wong, B J F

    2009-03-01

    Cartilage thermoforming is an emerging surgical technology which uses heat to accelerate stress relaxation in mechanically deformed tissue specimens. Heat induced shape change in cartilage is associated with complex thermo mechanical behavior of which the mechanisms are still a subject of debate. Differential scanning calorimetry (DSC) was used to characterize the threshold temperatures and enthalpies in cartilage as a function of water content. The DSC identified two enthalpic events in porcine nasal septal cartilage, which depend on the water content. The change in the water content of cartilage impacts the interactions between matrix macromolecules and water molecules, which may be associated with a bound-free water transformation (reversible process) and a denaturation of cartilage (irreversible process).

  17. Multimode near-field microwave monitoring of free water content of skin and imaging of tissue.

    PubMed

    Lofland, S E; Mazzatenta, J D; Croman, J; Tyagi, S D

    2007-03-07

    We have used the near-field scanning microwave microscopy (NSMM) technique in the 1-10 GHz range to monitor the free water content of skin. The water content is interpreted from the measured dielectric properties of the epidermis. The finger skin was first hydrated by soaking in water at 37 degrees C for 30 min followed by monitoring of water content as the free water evaporated under ambient conditions. The same technique has also been employed to image a 1 cm x 1 cm sample of chicken skin. It has been shown that variations exist in the resonant frequencies and quality factors of tissue under varying physical parameters. The samples analysed were as-received and thermally dehydrated or damaged chicken tissue samples. We contrast between the dielectric properties with the optical images. We also discuss possible application of our imaging technique in clinical monitoring of the wound healing process.

  18. Estimating the Relative Water Content of Single Leaves from Optical Polarization Measurements.

    NASA Astrophysics Data System (ADS)

    Vanderbilt, V. C.; Daughtry, C. S. T.; Dahlgren, R. P.

    2016-12-01

    Remotely sensing the water status of plants and the water content of canopies remain long term goals of remote sensing research. For monitoring canopy water status, existing approaches such as the Crop Water Stress Index and the Equivalent Water Thickness have limitations. The CWSI does not work well in humid regions, requires estimates of the vapor pressure deficit near the canopy during the remote sensing over-flight and, once stomata close, provides little information regarding the canopy water status. The EWI is based upon the physics of water-light interaction, not plant physiology. In this research, we applied optical polarization techniques to monitor the VIS/NIR light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both changed nonlinearly as each leaf dried, R increasing and T decreasing. Our results tie changes in the VIS/NIR R and T to leaf physiological changes - linking the light scattered out of the drying leaf interior to its relative water content and to changes in leaf cellular structure and pigments. Our results suggest remotely sensing the physiological water status of a single leaf - and perhaps of a plant canopy - might be possible in the future. However, using our approach to estimate the water status of a leaf does not appear possible at present, because our results display too much variability that we do not yet understand.

  19. Estimating the Relative Water Content of Single Leaves from Optical Polarization Measurements

    NASA Technical Reports Server (NTRS)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Remotely sensing the water status of plants and the water content of canopies remain long-term goals of remote sensing research. For monitoring canopy water status, existing approaches such as the Crop Water Stress Index and the Equivalent Water Thickness have limitations. The CWSI does not work well in humid regions, requires estimates of the vapor pressure deficit near the canopy during the remote sensing over-flight and, once stomata close, provides little information regarding the canopy water status. The EWI is based upon the physics of water-light interaction, not plant physiology. In this research, we applied optical polarization techniques to monitor the VISNIR light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both changed nonlinearly as each leaf dried, R increasing and T decreasing. Our results tie changes in the VISNIR R and T to leaf physiological changes linking the light scattered out of the drying leaf interior to its relative water content and to changes in leaf cellular structure and pigments. Our results suggest remotely sensing the physiological water status of a single leaf and perhaps of a plant canopy might be possible in the future. However, using our approach to estimate the water status of a leaf does not appear possible at present, because our results display too much variability that we do not yet understand.

  20. Microclimate, Water Potential, Transpiration, and Bole Dielectric Constant of Coniferous and Deciduous Tree Species in the Continental Boreal Ecotone of Central Alaska

    NASA Technical Reports Server (NTRS)

    Zimmermann, R.; McDonald, K.; Way, J.; Oren, R.

    1994-01-01

    Tree canopy microclimate, xylem water flux and xylem dielectric constant have been monitored in situ since June 1993 in two adjacent natural forest stands in central Alaska. The deciduous stand represents a mature balsam poplar site on the Tanana River floodplain, while the coniferous stand consists of mature white spruce with some black spruce mixed in. During solstice in June and later in summer, diurnal changes of xylem water potential were measured to investigate the occurrence and magnitude of tree transpiration and dielectric constant changes in stems.

  1. Microclimate, Water Potential, Transpiration, and Bole Dielectric Constant of Coniferous and Deciduous Tree Species in the Continental Boreal Ecotone of Central Alaska

    NASA Technical Reports Server (NTRS)

    Zimmermann, R.; McDonald, K.; Way, J.; Oren, R.

    1994-01-01

    Tree canopy microclimate, xylem water flux and xylem dielectric constant have been monitored in situ since June 1993 in two adjacent natural forest stands in central Alaska. The deciduous stand represents a mature balsam poplar site on the Tanana River floodplain, while the coniferous stand consists of mature white spruce with some black spruce mixed in. During solstice in June and later in summer, diurnal changes of xylem water potential were measured to investigate the occurrence and magnitude of tree transpiration and dielectric constant changes in stems.

  2. Research on water ice content in Cabeus crater using the data from the microwave radiometer onboard Chang'e-1 satellite

    NASA Astrophysics Data System (ADS)

    Meng, Zhiguo; Chen, Shengbo; Osei, Edward Matthew; Wang, Zijun; Cui, Tengfei

    2010-12-01

    The existence, formation and content of water ice in the lunar permanently shaded region is one of the important questions for the current Moon study. On October 9, 2009, the LCROSS mission spacecraft impacted the Moon, and the initial result verified the existence of water on the Moon. But the study on formation and content of water ice is still under debate. The existence of water ice can change the dielectric constants of the lunar regolith, and a microwave radiometer is most sensitive to the dielectric parameters. Based on this, in this paper, the radiation transfer model is improved according to the simulation results in high frequency. Then the mixture dielectric constant models, including Odelevsky model, Wagner and landau-Lifshitz model, Clau-sius model, Gruggeman-Hanai model, etc., are analyzed and compared. The analyzing results indicate that the biggest difference occurs between Lichtenecker model and the improved Dobson model. The values estimated by refractive model are the second biggest in all the models. And the results from Odelevsky model, strong fluctuation model, Wagner and Landau -Lifshitz model, Clausius model and Bruggeman-Hanai model are very near to each other. Thereafter, the relation between volume water ice content and microwave brightness temperature is constructed with Odelevsky mixing dielectric model and the improved radiative transfer simulation, and the volume water ice content in Cabeus crater is retrieved with the data from microwave radiometer onboard Chang'e-1 satellite. The results present that the improved radiative transfer model is proper for the brightness temperature simulation of the one infinite regolith layer in high frequency. The brightness temperature in Cabeus crater is 69.93 K (37 GHz), and the corresponding volume water ice content is about 2.8%.

  3. Effects of diesel engine speed and water content on emission characteristics of three-phase emulsions.

    PubMed

    Lin, Cherng-Yuan; Wang, Kuo-Hua

    2004-01-01

    The effects of water content of three-phase emulsions and engine speed on the combustion and emission characteristics of diesel engines were investigated in this study. The results show that a larger water content of water-in oil (W/O) and oil-in-water-in-oil (O/W/O) emulsion caused a higher brake specific fuel consumption (bsfc) value and a lower O2, as well as a lower NOx emission, but a larger CO emission. The increase in engine speed resulted in an increase of bsfc, exhaust gas temperature, fuel-to-air ratio, CO2 emission and a decrease of NOx, CO emission, and smoke opacity. Because of the physical structural differences, the three-phase O/W/O emulsions were observed to produce a higher exhaust gas temperature, a higher emulsion viscosity and a lower CO emission, in comparison with that of the two-phase W/O emulsion. In addition, the use of W/O emulsions with water content larger than 20% may cause diesel engines to shut down earlier than those running on O/W/O emulsions with the same water content. Hence, it is suggested that the emulsions with water content larger than 20% are not suitable for use as alternative fuel for diesel engines.

  4. Importance of Water Content of the Stratum Corneum in Mouse Models for Contact Hypersensitivity.

    PubMed

    Doi, Takaaki; Mizukawa, Yoshiko; Shimoda, Yurie; Yamazaki, Yoshimi; Shiohara, Tetsuo

    2017-01-01

    Although a marked rise in the prevalence of allergic diseases over the past few decades may be related to environmental factors in industrialized countries, evidence for the protective effect of humidity on the barrier function of the skin is still awaited. We asked whether an increase in the water content of stratum corneum at the site of hapten application had a strong impact on the magnitude of contact hypersensitivity (CHS). The magnitude of CHS, induced by either lipid-soluble or water-soluble hapten, was inversely correlated with the water content of stratum corneum at the hapten application site in the elicitation phase. An increase in the water content induced by exposure to high humidity for 6 hours was sufficient to ameliorate the magnitude of CHS even in mice with the genetic defect in attenuating the CHS responses, such as flaky tail mice. The reduced CHS was associated with downregulation of IL-1α, IL-4, and IFN-γ mRNA expression. Epicutaneously applied hapten can penetrate more readily through the stratum corneum with lower water content than that with higher water content, even after tape-stripping. These findings indicate that increased levels of water in the stratum corneum serve to ameliorate the CHS beyond the genetic effects. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  5. [Effects of water content on redox potential and carbon mineralization of wetland sediments].

    PubMed

    Yang, Gai-ren; Tong, Cheng-li; Xiao, He-ai; Wu, Jin-shui

    2009-08-15

    To better understand the effect of soil water contents on redox potential (Eh), and their impacts on C mineralization in natural wetland, sediment samples from 3 types of wetlands (fen, humus marsh and marshy meadow) in the San-jiang Plate region of North China were incubated (25 degrees C) for 155 d under a range of reducing and oxidizing conditions by controlling water contents (varied from 24% to 232% of water holding capacity) (WHC). CO2-C evolved during incubation was measured at different time intervals. Results showed that Eh of sediments decreased significantly as water content increased from 24% WHC (lighted moisturized) to about 100% WHC, then decreased slightly as water content increased further to a level of submersed (about 2 cm water-depths). The accumulative amount of CO2-C evolved from the sediments indicated that the optimum water contents for mineralization of organic C are 32%, 48% and 76%-100% WHC for sediments of fen, humus marsh, and marshy meadow, respectively. The relationship between mineralization rates and redox potentials (Eh) were well fitted with second order parabola equations (p < 0.05). Mineralization rates and accumulative amount of organic C displayed a positive correlation with Eh up to 300 mV. However, a significant negative correlation was observed when Eh increased above 300 mV. Results demonstrated that low redox potential is the controlling factor of carbon accumulation of wetland in San-jiang Plate region.

  6. High Water Contents in the Siberian Cratonic Mantle: An FTIR Study of Udachnaya Peridotite Xenoliths

    NASA Technical Reports Server (NTRS)

    Doucet, Luc S.; Peslier, Anne H.; Ionov, Dimitri A.; Brandon, Alan D.; Golovin, Alexander V.; Ashchepkov, Igor V.

    2013-01-01

    Water is believed to be a key factor controlling the long-term stability of cratonic lithosphere, but mechanisms responsible for the water content distribution in the mantle remain poorly constrained. Water contents were obtained by FTIR in olivine, pyroxene and garnet for 20 well-characterized peridotite xenoliths from the Udachnaya kimberlite (central Siberian craton) and equilibrated at 2-7 GPa. Water contents in minerals do not appear to be related to interaction with the host kimberlite. Diffusion modeling indicates that the core of olivines preserved their original water contents. The Udachnaya peridotites show a broad range of water contents in olivine (6.5 +/- 1.1 to 323 +- 65 ppm H2O (2 sigma)), and garnet (0 - 23 +/- 6 ppm H2O). The water contents of olivine and garnet are positively correlated with modal clinopyroxene, garnet and FeO in olivine. Water-rich garnets are also rich in middle rare earth elements. This is interpreted as the result of interaction between residual peridotites and water rich-melts, consistent with modal and cryptic metasomatism evidenced in the Siberian cratonic mantle. The most water-rich Udachnaya minerals contain 2 to 3 times more water than those from the Kaapvaal craton, the only craton with an intact mantle root for which water data is available. The highest water contents in olivine and orthopyroxene in this study (>= 300 ppm) are found at the bottom of the lithosphere (> 6.5 GPa). This is in contrast with the Kaapvaal craton where the olivines of peridotites equilibrated at > 6.4 GPa have < 1 ppm H2O. The latter "dry" olivine may make the base of the Kaapvaal cratonic root strong and thus protects it from erosion by the convective mantle The calculated viscosity for water-rich Udachnaya peridotites at > 6 GPa is lower or similar (8.4× 10(exp 16) to 8.0× 10(exp 18) Pa./s) to that of the asthenosphere (<= 3.7x10(exp 18) Pa./s ). Such lithologies would not be able to resist delamination by the convecting asthenosphere

  7. Porous media matric potential and water content measurements during parabolic flight.

    PubMed

    Norikane, Joey H; Jones, Scott B; Steinberg, Susan L; Levine, Howard G; Or, Dani

    2005-01-01

    Control of water and air in the root zone of plants remains a challenge in the microgravity environment of space. Due to limited flight opportunities, research aimed at resolving microgravity porous media fluid dynamics must often be conducted on Earth. The NASA KC-135 reduced gravity flight program offers an opportunity for Earth-based researchers to study physical processes in a variable gravity environment. The objectives of this study were to obtain measurements of water content and matric potential during the parabolic profile flown by the KC-135 aircraft. The flight profile provided 20-25 s of microgravity at the top of the parabola, while pulling 1.8 g at the bottom. The soil moisture sensors (Temperature and Moisture Acquisition System: Orbital Technologies, Madison, WI) used a heat-pulse method to indirectly estimate water content from heat dissipation. Tensiometers were constructed using a stainless steel porous cup with a pressure transducer and were used to measure the matric potential of the medium. The two types of sensors were placed at different depths in a substrate compartment filled with 1-2 mm Turface (calcined clay). The ability of the heat-pulse sensors to monitor overall changes in water content in the substrate compartment decreased with water content. Differences in measured water content data recorded at 0, 1, and 1.8 g were not significant. Tensiometer readings tracked pressure differences due to the hydrostatic force changes with variable gravity. The readings may have been affected by changes in cabin air pressure that occurred during each parabola. Tensiometer porous membrane conductivity (function of pore size) and fluid volume both influence response time. Porous media sample height and water content influence time-to-equilibrium, where shorter samples and higher water content achieve faster equilibrium. Further testing is needed to develop these sensors for space flight applications.

  8. Water Content of the Oceanic Lithosphere at Hawaii from FTIR Analysis of Peridotite Xenoliths

    NASA Technical Reports Server (NTRS)

    Peslier, Anne H.; Bizmis, Michael

    2013-01-01

    Although water in the mantle is mostly present as trace H dissolved in minerals, it has a large influence on its melting and rheological properties. The water content of the mantle lithosphere beneath continents is better constrained by abundant mantle xenolith data than beneath oceans where it is mainly inferred from MORB glass analysis. Using Fourier transform infrared (FTIR) spectrometry, we determined the water content of olivine (Ol), clinopyroxene (Cpx) and orthopyroxene (Opx) in spinel peridotite xenoliths from Salt Lake Crater, Oahu, Hawaii, which are thought to represent fragments of the Pacific oceanic lithosphere that was refertilized by alkalic Hawaiian melts. Only Ol exhibits H diffusion profiles, evidence of limited H loss during xenolith transport to the surface. Water concentrations (Ol: 9-28 ppm H2O, Cpx: 246-566 ppm H2O, Opx: 116-224 ppm H2O) are within the range of those from continental settings but higher than those from Gakkel ridge abyssal peridotites. The Opx H2O contents are similar to those of abyssal peridotites from Atlantic ridge Leg 153 (170-230 ppm) but higher than those from Leg 209 (10- 14 ppm). The calculated bulk peridotite water contents (94 to 144 ppm H2O) are in agreement with MORB mantle source water estimates and lower than estimates for the source of Hawaiian rejuvenated volcanism (approx 540 ppm H2O) . The water content of Cpx and most Opx correlates negatively with spinel Cr#, and positively with pyroxene Al and HREE contents. This is qualitatively consistent with the partitioning of H into the melt during partial melting, but the water contents are too high for the degree of melting these peridotites experienced. Melts in equilibrium with xenolith minerals have H2O/Ce ratios similar to those of OIB

  9. Estimation of soil water content in Mongolian grasslands using a spectral radiometer

    NASA Astrophysics Data System (ADS)

    Sekiyama, Ayako; Shimada, Sawahiko; Toyoda, Hiromichi; Yokohama, Michinari

    Harsh winter conditions, called dzud, experienced in Mongolia in recent years have caused significant damage to their livestock. Grassland deterioration resulting from soil water shortage coupled with the lack of precipitation during summer is one of the causative factors of this damage. Collecting grassland information over a wide area by satellite remote sensing is useful for spatial prediction of dzud. In this study, we conducted a fundamental experiment to estimate soil water content using a spectral radiometer (observed wavelength range, 302.9-1145.8 nm), which uses the same sensor as a satellite. Soil spectral reflectance was measured under open-air conditions using a spectral radiometer at the experiment station. The soil water content was controlled in several samples by adding water, and the spectral reflectance of the sample surface was measured. Four spectral bands were selected under the observed wavelength for application to the satellite data. The soil spectral reflectance was normalized by the sum of the reflectance values of each band. It was found that a normalized soil reflectance pattern changed to a flat pattern with a decrease in soil water content. Fujiwara et al. (1996) proposed a pattern decomposition method to decompose a mixed spectral reflectance pattern, e.g., land cover of soil and vegetation, into its respective parts. The decomposition coefficient for each pattern was calculated based on the mixed content of the reflectance patterns. In this study, a new spectral pattern, observed as a flat shape in the reflectance curve, was derived to extract the components of soil water content. Pattern decomposition was conducted using soil and flat model patterns, and their decomposition coefficients were calculated. The correlation between soil water content and the flat model pattern decomposition coefficient was calculated by regression analysis. To apply this method to field data, we conducted site investigations in Mongolian grasslands

  10. Porous media matric potential and water content measurements during parabolic flight

    NASA Technical Reports Server (NTRS)

    Norikane, Joey H.; Jones, Scott B.; Steinberg, Susan L.; Levine, Howard G.; Or, Dani

    2005-01-01

    Control of water and air in the root zone of plants remains a challenge in the microgravity environment of space. Due to limited flight opportunities, research aimed at resolving microgravity porous media fluid dynamics must often be conducted on Earth. The NASA KC-135 reduced gravity flight program offers an opportunity for Earth-based researchers to study physical processes in a variable gravity environment. The objectives of this study were to obtain measurements of water content and matric potential during the parabolic profile flown by the KC-135 aircraft. The flight profile provided 20-25 s of microgravity at the top of the parabola, while pulling 1.8 g at the bottom. The soil moisture sensors (Temperature and Moisture Acquisition System: Orbital Technologies, Madison, WI) used a heat-pulse method to indirectly estimate water content from heat dissipation. Tensiometers were constructed using a stainless steel porous cup with a pressure transducer and were used to measure the matric potential of the medium. The two types of sensors were placed at different depths in a substrate compartment filled with 1-2 mm Turface (calcined clay). The ability of the heat-pulse sensors to monitor overall changes in water content in the substrate compartment decreased with water content. Differences in measured water content data recorded at 0, 1, and 1.8 g were not significant. Tensiometer readings tracked pressure differences due to the hydrostatic force changes with variable gravity. The readings may have been affected by changes in cabin air pressure that occurred during each parabola. Tensiometer porous membrane conductivity (function of pore size) and fluid volume both influence response time. Porous media sample height and water content influence time-to-equilibrium, where shorter samples and higher water content achieve faster equilibrium. Further testing is needed to develop these sensors for space flight applications.

  11. Porous media matric potential and water content measurements during parabolic flight

    NASA Technical Reports Server (NTRS)

    Norikane, Joey H.; Jones, Scott B.; Steinberg, Susan L.; Levine, Howard G.; Or, Dani

    2005-01-01

    Control of water and air in the root zone of plants remains a challenge in the microgravity environment of space. Due to limited flight opportunities, research aimed at resolving microgravity porous media fluid dynamics must often be conducted on Earth. The NASA KC-135 reduced gravity flight program offers an opportunity for Earth-based researchers to study physical processes in a variable gravity environment. The objectives of this study were to obtain measurements of water content and matric potential during the parabolic profile flown by the KC-135 aircraft. The flight profile provided 20-25 s of microgravity at the top of the parabola, while pulling 1.8 g at the bottom. The soil moisture sensors (Temperature and Moisture Acquisition System: Orbital Technologies, Madison, WI) used a heat-pulse method to indirectly estimate water content from heat dissipation. Tensiometers were constructed using a stainless steel porous cup with a pressure transducer and were used to measure the matric potential of the medium. The two types of sensors were placed at different depths in a substrate compartment filled with 1-2 mm Turface (calcined clay). The ability of the heat-pulse sensors to monitor overall changes in water content in the substrate compartment decreased with water content. Differences in measured water content data recorded at 0, 1, and 1.8 g were not significant. Tensiometer readings tracked pressure differences due to the hydrostatic force changes with variable gravity. The readings may have been affected by changes in cabin air pressure that occurred during each parabola. Tensiometer porous membrane conductivity (function of pore size) and fluid volume both influence response time. Porous media sample height and water content influence time-to-equilibrium, where shorter samples and higher water content achieve faster equilibrium. Further testing is needed to develop these sensors for space flight applications.

  12. Effect of water content and temperature on inactivation kinetics of myrosinase in broccoli (Brassica oleracea var. italica).

    PubMed

    Oliviero, T; Verkerk, R; Van Boekel, M A J S; Dekker, M

    2014-11-15

    Broccoli belongs to the Brassicaceae plant family consisting of widely eaten vegetables containing high concentrations of glucosinolates. Enzymatic hydrolysis of glucosinolates by endogenous myrosinase (MYR) can form isothiocyanates with health-promoting activities. The effect of water content (WC) and temperature on MYR inactivation in broccoli was investigated. Broccoli was freeze dried obtaining batches with WC between 10% and 90% (aw from 0.10 to 0.96). These samples were incubated for various times at different temperatures (40-70°C) and MYR activity was measured. The initial MYR inactivation rates were estimated by the first-order reaction kinetic model. MYR inactivation rate constants were lower in the driest samples (10% WC) at all studied temperatures. Samples with 67% and 90% WC showed initial inactivation rate constants all in the same order of magnitude. Samples with 31% WC showed intermediate initial inactivation rate constants. These results are useful to optimise the conditions of drying processes to produce dried broccoli with optimal MYR retention for human health.

  13. Validation of Soil Water Content Estimation Method on Agricultural Regions in South Korea

    NASA Astrophysics Data System (ADS)

    Shin, Y.; Kim, M.

    2016-12-01

    The continuous water stress caused by decrease of soil water has a direct influence to the crop growth in a upland crop area. The agricultural drought is occured if water requirement is not supplied timely in crop growh process. It is more important to understand the soil characteristics for high accuracy soil moisture estimation because of the soil water contents largely depends on soil properties. The RDA(Rural Development Administration) has provided real-time soil moisture observations corrected for 71 points in the South Korea. In this study, we developed a soil water content estimation method that considered soil hydraulic parameters for the observation points of soil water content in agricultural regions operated by the RDA. SWAP(Soil-Water-Atmosphere-Plant) model was used in the estimation of soil water contents. The soil hydraulic parameters that is the input data of the SWAP model were estimated using the ROSETTA model developed by the U.S. Department of Agriculture(USDA). Meteorological data observed from AWS(Automatic Weather Station) were used including daily maximum temperature(°), daily minimum temperature(°), relative humidity(%), solar radiation, wind speed and precipitation data. We choosed 56 stations there are no missing of meteorological data and have soil physical properties. For the verification of soil water content estimation method, we used Haenam KoFlux observation data that are observed long-term soil water contents over 2009-2015(2014 missing) years. In the case of 2015, there are good reproducibility between observation of soil water contents and results of SWAP model simulation with R2=0.72, RMSE=0.026 and TCC=0.849. In the case of precipitation event, the simulation results were slightly overestimated more than observation. However there are good reproducibility in the case of soil water reduction due to continuous non-precipitation periods. We have simulated the soil water contents of the 56 stations that being operated in the RDA

  14. Estimating water content in an active landfill with the aid of GPR

    SciTech Connect

    Yochim, April; Zytner, Richard G.; McBean, Edward A.; Endres, Anthony L.

    2013-10-15

    Highlights: • Limited information in the literature on the use of GPR to measure in situ water content in a landfill. • Developed GPR method allows measurement of in situ water content in a landfill. • Developed GPR method is appealing to waste management professionals operating landfills. - Abstract: Landfill gas (LFG) receives a great deal of attention due to both negative and positive environmental impacts, global warming and a green energy source, respectively. However, predicting the quantity of LFG generated at a given landfill, whether active or closed is difficult due to the heterogeneities present in waste, and the lack of accurate in situ waste parameters like water content. Accordingly, ground penetrating radar (GPR) was evaluated as a tool for estimating in situ water content. Due to the large degree of subsurface heterogeneity and the electrically conductive clay cap covering landfills, both of which affect the transmission of the electromagnetic pulses, there is much scepticism concerning the use of GPR to quantify in situ water content within a municipal landfill. Two landfills were studied. The first landfill was used to develop the measurement protocols, while the second landfill provided a means of confirming these protocols. GPR measurements were initially completed using the surface GPR approach, but the lack of success led to the use of borehole (BH) GPR. Both zero offset profiling (ZOP) and multiple offset gathers (MOG) modes were tried, with the results indicating that BH GPR using the ZOP mode is the most simple and efficient method to measure in situ water content. The best results were obtained at a separation distance of 2 m, where higher the water content, smaller the effective separation distance. However, an increase in water content did appear to increase the accuracy of the GPR measurements. For the effective separation distance of 2 m at both landfills, the difference between GPR and lab measured water contents were reasonable

  15. GROUND WATER ISSUE - CALCULATION AND USE OF FIRST-ORDER RATE CONSTANTS FOR MONITORED NATURAL ATTENUATION STUDIES

    EPA Science Inventory

    This issue paper explains when and how to apply first-order attenuation rate constant calculations in monitored natural attenuation (MNA) studies. First-order attenuation rate constant calculations can be an important tool for evaluating natural attenuation processes at ground-wa...

  16. Water content and bark thickness of Norway spruce (Picea abies) stems: phloem water capacitance and xylem sap flow.

    PubMed

    Gall, Rolf; Landolt, W; Schleppi, P; Michellod, V; Bucher, J B

    2002-06-01

    To determine the relationship between phloem transport and changes in phloem water content, we measured temporal and spatial variations in water content and sucrose, glucose and fructose concentrations in phloem samples and phloem exudates of 70- and 30-year-old Norway spruce trees (Picea abies (L.) Karst.). Large temporal and spatial variations in phloem water content (1.4-2.6 mg mg(dw)(-1)) and phloem total sugar concentration (31-70 mg g(dw)(-1)) paralleled each other (r(2) = 0.83, P < 0.0001 for the temporal profile and r(2) = 0.96, P < 0.008 for the spatial profile), indicating that phloem water content depends on the total amount of sugar to be transferred. Changes in phloem water content were unrelated to changes in bark thickness. Maximum changes in phloem water content calculated from dendrometer readings were only 8-11% of the maximum measured changes in phloem water content, indicating that reversible changes in bark thickness did not reflect changes in internal water relations. We also studied the relationship between xylem sap velocity and changes in bark thickness in 70-year-old trees during summer 1999 and winter 1999-2000. Sap flow occurred sporadically throughout the winter, but there was no relationship between bark shrinkage or swelling and sap velocity. In winter, mean daily xylem sap velocity was significantly correlated with mean daily vapor pressure deficit and air temperature (P < 0.0001, in both cases). Changes in bark thickness corresponded with both short- and long-term changes in relative humidity, in both winter and summer. Under controlled conditions at > 0 degrees C, changes in relative humidity alone caused changes in thickness of boiled bark samples. Because living bark of Norway spruce trees contains large areas with crushed and dead sieve cell zones-up to 24% of the bark is air-filled space-we suggest that this space can compensate for volume changes in living phloem cells independently of total tissue water content. We conclude

  17. A Novel Low-Cost Instrumentation System for Measuring the Water Content and Apparent Electrical Conductivity of Soils.

    PubMed

    Rêgo Segundo, Alan Kardek; Martins, José Helvecio; Monteiro, Paulo Marcos de Barros; de Oliveira, Rubens Alves; Freitas, Gustavo Medeiros

    2015-10-05

    The scarcity of drinking water affects various regions of the planet. Although climate change is responsible for the water availability, humanity plays an important role in preserving this precious natural resource. In case of negligence, the likely trend is to increase the demand and the depletion of water resources due to the increasing world population. This paper addresses the development, design and construction of a low cost system for measuring soil volumetric water content (θ), electrical conductivity (σ) and temperature (T), in order to optimize the use of water, energy and fertilizer in food production. Different from the existing measurement instruments commonly deployed in these applications, the proposed system uses an auto-balancing bridge circuit as measurement method. The proposed models to estimate θ and σ and correct them in function of T are compared to the ones reported in literature. The final prototype corresponds to a simple circuit connected to a pair of electrode probes, and presents high accuracy, high signal to noise ratio, fast response, and immunity to stray capacitance. The instrument calibration is based on salt solutions with known dielectric constant and electrical conductivity as reference. Experiments measuring clay and sandy soils demonstrate the satisfactory performance of the instrument.

  18. Cell wall water content has a direct effect on extensibility in growing hypocotyls of sunflower (Helianthus annuus L.).

    PubMed

    Evered, Carol; Majevadia, Bhavita; Thompson, David Stuart

    2007-01-01

    It has been proposed that spacing between cellulose microfibrils within plant cell walls may be an important determinant of their mechanical properties. A consequence of this hypothesis is that the water content of cell walls may alter their extensibility and that low water potentials may directly reduce growth rates by reducing cell wall spacing. This paper describes a number of experiments in which the water potential of frozen and thawed growing hypocotyls of sunflower (Helianthus annuus L.) were altered using solutions of high molecular weight polyethylene glycol (PEG) or Dextran while their extension under constant stress was monitored using a creep extensiometer (frozen and thawed tissue was used to avoid confounding effects of turgor or active responses to the treatments). Clear reductions in extensibility were observed using both PEG and Dextran, with effects observed in hypocotyl segments treated with PEG 35 000 solutions with osmotic pressures of > or =0.21 MPa suggesting that the relatively mild stresses required to reduce water potentials of plants in vivo by 0.21 MPa may be sufficient to reduce growth rates via a direct effect on wall extensibility. It is noted, therefore, that the water binding capacity of plant cell walls may be of ecophysiological importance. Measurements of cell walls of sunflower hypocotyls using scanning electron microscopy confirmed that treatment of hypocotyls with PEG solutions reduced wall thickness, supporting the hypothesis that the spatial constraint of movement of cellulose microfibrils affects the mechanical properties of the cell wall.

  19. A Novel Low-Cost Instrumentation System for Measuring the Water Content and Apparent Electrical Conductivity of Soils

    PubMed Central

    Rêgo Segundo, Alan Kardek; Martins, José Helvecio; Monteiro, Paulo Marcos de Barros; de Oliveira, Rubens Alves; Freitas, Gustavo Medeiros

    2015-01-01

    The scarcity of drinking water affects various regions of the planet. Although climate change is responsible for the water availability, humanity plays an important role in preserving this precious natural resource. In case of negligence, the likely trend is to increase the demand and the depletion of water resources due to the increasing world population. This paper addresses the development, design and construction of a low cost system for measuring soil volumetric water content (θ), electrical conductivity (σ) and temperature (T), in order to optimize the use of water, energy and fertilizer in food production. Different from the existing measurement instruments commonly deployed in these applications, the proposed system uses an auto-balancing bridge circuit as measurement method. The proposed models to estimate θ and σ and correct them in function of T are compared to the ones reported in literature. The final prototype corresponds to a simple circuit connected to a pair of electrode probes, and presents high accuracy, high signal to noise ratio, fast response, and immunity to stray capacitance. The instrument calibration is based on salt solutions with known dielectric constant and electrical conductivity as reference. Experiments measuring clay and sandy soils demonstrate the satisfactory performance of the instrument. PMID:26445049

  20. Effects of the water content on the growth rate of AgCl nanoparticles in a reversed micelle system.

    PubMed

    Kimijima, Ken'ichi; Sugimoto, Tadao

    2005-06-15

    The effects of water content on the growth rate and the final particle size of AgCl nanoparticles in a reversed micelle (RM) system of polyoxyethylene (6) nonylphenyl ether (NP-6)/water/cyclohexane were investigated using a double-jet technique, in which RM solutions of AgNO(3) and KCl were added concurrently to a RM solution containing the excess concentration of chloride ion. As a result, the particle growth rate and the final particle size at a constant Rw ( identical with[water]/[surfactant]) below 5 were found to be in excellent agreement with our theoretical prediction based on a dynamic Ostwald ripening mechanism governed by the overall solubility of the solid and the diffusivity of the reversed micelles, whereas the final particle size was far beyond the size of the water pool of a reversed micelle. Thus, the dramatic reduction of the particle size in the RM system can be explained by the drastic reduction of the overall solubility of the solid and the small diffusivity of the bulky reversed micelles as a carrier of silver ion, and not by the size of the water pool of a reversed micelle as conventionally explained. Some additional contribution of a coagulation process was also suggested in a high Rw range above 5. Significant coagulation of AgCl particles was observed in a RM system with AOT in place of NP-6 even under the standard conditions for the NP-6 system.

  1. Modeling the release of E. coli D21g with transients in water content

    USDA-ARS?s Scientific Manuscript database

    Transients in water content are well known to mobilize colloids that are retained in the vadose zone. However, there is no consensus on the proper model formulation to simulate colloid release during drainage and imbibition. We present a model that relates colloid release to changes in the air-water...

  2. Seasonal patterns of bole water content in old growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)

    EPA Science Inventory

    Large, old conifer trees in the Pacific Northwest (PNW), USA purportedly ameliorate the effects of seasonal summer drought by drawing down the water content of bole tissues over the summer months and refilling during the winter. Continuous monitoring of bole relative water conten...

  3. Estimating topsoil water content of clay soils with data from time-lapse electrical conductivity surveys

    USDA-ARS?s Scientific Manuscript database

    Spatial estimation of soil water content (') at the field, hillslope, or catchment scale is required in numerous applications. Time-lapse electrical resistivity and electrical conductivity surveys were recognized as the useful source of information about both spatial variations in soil water conten...

  4. Effect of water content on transient nonequilibrium NAPL-gas mass transfer during soil vapor extraction.

    PubMed

    Yoon, Hongkyu; Kim, Joong Hoon; Liljestrand, Howard M; Khim, Jeehyeong

    2002-01-01

    The effect of water content on the volatilization of nonaqueous phase liquid (NAPL) in unsaturated soils was characterized by one-dimensional venting experiments conducted to evaluate the lumped mass transfer coefficient. An empirical correlation based upon the modified Sherwood number, Peclet number, and normalized mean grain size was used to estimate initial lumped mass transfer coefficients over a range of water content. The effects of water content on the soil vapor extraction SVE process have been investigated through experimentation and mathematical modeling. The experimental results indicated that a rate-limited NAPL-gas mass transfer occurred in water-wet soils. A severe mass transfer limitation was observed at 61.0% water saturation where the normalized effluent gas concentrations fell below 1.0 almost immediately, declined exponentially from the initiation of venting, and showed long tailing. This result was attributed to the reduction of interfacial area between the NAPL and mobile gas phases due to the increased water content. A transient mathematical model describing the change of the lumped mass transfer coefficient was used. Simulations showed that the nonequilibrium mass transfer process could be characterized by the exponent beta, a parameter which described the reduction of the specific area available for NAPL volatilization. The nonequilibrium mass transfer limitations were controlled by the soil mean grain size and pore gas velocity, were well described by beta values below 1.0 at low water saturation, and were well predicted with beta values greater than 1.0 at high water saturation.

  5. BOLE WATER CONTENT SHOWS LITTLE SEASONAL VARIATION IN CENTURY-OLD DOUGLAS-FIR TREES

    EPA Science Inventory

    Purportedly, large Douglas-fir trees in the American Pacific Northwest use water stored in bole tissues to ameliorate the effects of seasonal summer drought, the water content of bole tissues being drawn down over the summer months and replenished during the winter. Continuous mo...

  6. BOLE WATER CONTENT SHOWS LITTLE SEASONAL VARIATION IN CENTURY-OLD DOUGLAS-FIR TREES

    EPA Science Inventory

    Purportedly, large Douglas-fir trees in the American Pacific Northwest use water stored in bole tissues to ameliorate the effects of seasonal summer drought, the water content of bole tissues being drawn down over the summer months and replenished during the winter. Continuous mo...

  7. The Mineral Content of U.S. Drinking and Municipal Water

    USDA-ARS?s Scientific Manuscript database

    Objective: The mineral composition of tap water may contribute significant amounts of some minerals to dietary intake. The USDA’s Nutrient Data Laboratory (NDL) conducted a study of the mineral content of residential tap water, to generate new current data for the USDA National Nutrient Database. ...

  8. Surface soil water content spatial organization within irrigated and non-irrigated agricultural fields

    USDA-ARS?s Scientific Manuscript database

    Understanding soil water content variability is important for monitoring and modeling of land surface processes as well as land and water management practices. With regards to in situ probes, it is sometimes assumed that a single local measurement can represent the larger domain, mostly for practic...

  9. Fluoride content of bottled drinking waters available in Riyadh, Saudi Arabia

    PubMed Central

    Aldrees, Abdullah M.; Al-Manea, Saad M.

    2010-01-01

    Aims This study aimed to examine the fluoride concentration of commercially available bottled water products in Riyadh, Saudi Arabia, and to assess the accuracy of the labeling of fluoride concentration on the tested brands. Methods Fifteen randomly selected commercial brands of bottled water were obtained from supermarkets in Riyadh, Saudi Arabia. Three bottles of each brand were purchased, and fluoride content was measured using a combination fluoride-ion-selective electrode. The average reading for each brand was estimated and also compared with the fluoride content printed on the label. Results The mean (±SD) fluoride content of the 12 local bottled water samples was 0.79 (±0.09) mg/L with a range from 0.5 to 0.83 mg/L. The mean fluoride concentration of the three imported brands was 0.67 (±0.02) mg/L with a narrow range of fluoride content (0.65–0.69). All tested samples mention the fluoride content on the label except two imported brands. Five samples showed a significant difference between our evaluation and stated content of fluoride that ranged between +0.46 and −0.2 mg/L. Conclusions Bottled drinking waters available in Riyadh, Saudi Arabia contain differing concentration of fluoride, but within a safe range for use as a source of systemic fluoride. In addition, the manufactures’ labeling of fluoride content may be inaccurate. PMID:23960496

  10. Science Is Constantly Cool.

    ERIC Educational Resources Information Center

    Eichinger, John

    1996-01-01

    Presents an activity in which students attempt to keep water at a constant temperature. Helps students in grades three to six hone their skills in prediction, observation, measurement, data collection, graphing, data analysis, and communication. (JRH)

  11. Assessment of the manganese content of the drinking water source in Yancheng, China.

    PubMed

    Wang, Jinnan; Li, Aimin; Wang, Qiongjie; Zhou, Yang; Fu, Lichun; Li, Yan

    2010-10-15

    Excessive intake of manganese can damage the nervous system of the human body. In August 2009, the manganese content of the drinking water source in Yancheng exceeded the national standard of drinking water source, which influenced the daily life of the local residents. The aim of this study was to investigate the factors leading to the manganese content of river water in Yancheng exceeding the national standard. To the data, the manganese content of surface water in Yancheng already met the national standard of drinking water source in September 2009, but the manganese content of river sediment was relatively high, especially in Mangshe River and Tongyu River. It was worthwhile to note that the soluble manganese content of the sediment in Mangshe River was even as high as 270 mg kg(-1), which suggested that the release of manganese from the sediment was the major cause of the pollution. The manganese content of the soil near the rivers was also determined, and the results indicated that the wastewater and waste slag discharged by the stainless steel factories nearby were the main pollution sources of manganese. Furthermore, the environmental factors affecting the release of manganese from the sediment were also investigated.

  12. Remote sensing of fuel moisture content from canopy water indices and normalized dry matter index

    NASA Astrophysics Data System (ADS)

    Raymond Hunt, E.; Wang, Lingli; Qu, John J.; Hao, Xianjun

    2012-01-01

    Fuel moisture content (FMC), an important variable for predicting the occurrence and spread of wildfire, is the ratio of foliar water content and foliar dry matter content. One approach for the remote sensing of FMC has been to estimate the change in canopy water content over time by using a liquid-water spectral index. Recently, the normalized dry matter index (NDMI) was developed for the remote sensing of dry matter content using high-spectral-resolution data. The ratio of a spectral water index and a dry matter index corresponds to the ratio of foliar water and dry matter contents; therefore, we hypothesized that FMC may be remotely sensed with a spectral water index divided by NDMI. For leaf-scale simulations using the PROSPECT (leaf optical properties spectra) model, all water index/NDMI ratios were significantly related to FMC with a second-order polynomial regression. For canopy-scale simulations using the SAIL (scattering by arbitrarily inclined leaves) model, two water index/NDMI ratios, with numerators of the normalized difference infrared index (NDII) and the normalized difference water index (NDWI), predicted FMC with R2 values of 0.900 and 0.864, respectively. Leaves from three species were dried or stacked to vary FMC; measured NDII/NDMI was best related to FMC. Whereas the planned NASA mission Hyperspectral Infrared Imager (HyspIRI) will have high spectral resolution and very high signal-to-noise properties, the planned 19-day repeat frequency will not be sufficient for monitoring FMC with NDII/NDMI. Because increased fire frequency is expected with climatic change, operational assessment of FMC at large scales may require polar-orbiting environmental sensors with narrow bands to calculate NDMI.

  13. Spectrophotometric determination of acidity constants of 2-(2-Thiazolylazo)-Cresol in various water-organic solvent media mixtures using chemometrics methods.

    PubMed

    Momeni-Isfahani, Tahereh; Niazi, Ali

    2014-01-01

    The combination of soft- and hard-modeling was used to the spectrophotometric studies of the acidity constants of 2-(2-Thiazolylazo)-Cresol (TAC) at 25°C and at ionic strength 0.1 mol L(-1) in pure water as well as in aqueous media containing variable percentages (10-50%) of organic solvents. The organic solvents used were methanol, ethanol, dimethyl formamide (DMF) and 1,4-dioxane. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program was applied for determining acidity constants and pure spectra of different form of TAC. Results show that the acidity constants of TAC are influenced as the percentages of solvents added to the solution. The corresponding pKa values in solvent-water mixtures were determined. There are linear relationships between acidity constants and the mole fraction of organic solvents in the solvent mixtures. The effects of various solvents on absorption properties and acidity constants of each component are also discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Pb and Cd Contents in Soil, Water, and Trees at an Afforestation Site, South China.

    PubMed

    Pei, Nancai; Chen, Bufeng; Liu, Shuguang

    2015-11-01

    Pb and Cd contents in 13 plantation tree species (leaf and branch components), soil, water (groundwater and river water) at a young (3-5 year-old) seashore afforestation stand were investigated in Nansha district, Guangzhou city in southern China. The results showed that (1) soil, rather than water or trees, had the highest content of both Pb (averagely 48.79 mg/kg) and Cd (0.50 mg/kg), demonstrating that soil might function as a major reservoir for extraneously derived heavy metals; (2) Pb content was higher in branches than in leaves, but Cd content appeared similar in both components, implying possibly different accumulation mechanisms in trees; (3) Pb and Cd appeared to accumulate differently among some tree taxa, whereas almost no significant difference was detected between introduced and indigenous species. The study indicated that trees were potentially useful to remediate sites contaminated with Pb and Cd in the urbanized areas.

  15. Mineral content of water and food in fluorotic villages and prevalence of dental fluorosis.

    PubMed

    Bhargavi, V; Khandare, Arjun L; Venkaiah, K; Sarojini, G

    2004-09-01

    The fluoride (F), calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), and phosphorus (P) content in potable water and food samples from endemic and nonendemic villages for fluorosis were analyzed. It was found that the F content in water was significantly higher (p<0.01) in endemic villages (4.20+/-1.6 ppm) than control villages (0.63+/-0.15 ppm), whereas the Ca, Cu, and Mg contents were found to be significantly lower (p<0.05) in endemic villages compared to control villages. However, there was no significant difference in Zn and P contents between the villages. Foods grown in endemic villages contained significantly higher (p<0.01) fluoride content as compared to control villages. There was no significant difference in Ca, Mg, P, and Zn contents in food grown in endemic and control villages. Copper content in cereals (p<0.05), pulses (p<0.01), and vegetables (p<0.01) in endemic villages was found significantly higher as compared to control villages. The overall prevalence of dental fluorosis in six endemic villages was 97.4% in boys and 96% in girls, which was significantly higher (p<0.01) than that of control villages, where it was 10.5% in boys and 8.3% in girls. The prevalence of dental fluorosis was positively correlated (r=0.125, p<0.01) to fluoride and negatively correlated to Ca and Cu content in drinking water in endemic villages.

  16. Are Fundamental Constants Really Constant?

    ERIC Educational Resources Information Center

    Swetman, T. P.

    1972-01-01

    Dirac's classical conclusions, that the values of e2, M and m are constants and the quantity of G decreases with time. Evoked considerable interest among researchers and traces historical development by which further experimental evidence points out that both e and G are constant values. (PS)

  17. Are Fundamental Constants Really Constant?

    ERIC Educational Resources Information Center

    Swetman, T. P.

    1972-01-01

    Dirac's classical conclusions, that the values of e2, M and m are constants and the quantity of G decreases with time. Evoked considerable interest among researchers and traces historical development by which further experimental evidence points out that both e and G are constant values. (PS)

  18. Prediction of the vapor-liquid distribution constants for volatile nonelectrolytes in water up to its critical temperature

    NASA Astrophysics Data System (ADS)

    Plyasunov, Andrey V.; Shock, Everett L.

    2003-12-01

    The distribution of solutes between coexisting liquid and vapor phases of water can be expressed by the distribution constant, K D, defined as K D= limitlim x→0y/x, where y and x stand for the mole fraction concentrations of a solute in vapor and liquid phases, respectively. Research reported here is concerned with the prediction of this property, K D, for volatile nonelectrolytes, over the whole temperature range of existence of the vapor-liquid equilibrium for water, i.e. from 273 K to the critical temperature at 647.1 K. A simple empirical method is proposed to extrapolate the values of K D from 298 K to 500-550 K. Calculations at higher temperatures are based on the theoretical relation that establishes the proportionality between RTlnK D and the Krichevskii parameter, A Kr, which is the single most important property of a solute at near-critical conditions, and can be evaluated using the method proposed here. The comparison of predicted and experimental values of K D and A Kr for a few well-studied solutes reveals the satisfactory performance of the proposed method. It appears that the accuracy of predictions in the framework of this method is limited mainly by the accuracy of the values of the thermodynamic functions of hydration of solutes at 298 K, and that the best way to improve the quality of predictions of K D and A Kr is to increase the inventory of accurate calorimetric enthalpy and heat capacity data for aqueous solutes at 298 K. We stress that the values of the Krichevskii parameter, such as those generated in this study, are of crucial importance for reliable predictions of the chemical potential and its derivatives (V 2o, Cp 2o) for aqueous solutes at near-critical and supercritical conditions. Values of K D and A Kr are predicted for many inorganic volatile nonelectrolytes and some halogenated derivatives of methane and ethene. We show that both ln K D and A Kr for aqueous organic solutes follow group additivity systematics, and we derive a set

  19. A new fast response instrument for measuring total water content from aircraft

    NASA Astrophysics Data System (ADS)

    Nicholls, S.; Leighton, J.; Barker, R.

    1990-10-01

    A device for measuring the total water content of a parcel of air from an aircraft has been developed. The total water of a parcel of air is a conserved quantity, independent of phase changes, provided there is no transport of water through the parcel boundaries. Current airborne hygrometers normally attempt to measure the water content in individual phases and the presence of other phases invariably influences the quality of the data. However, any liquid water or ice entering this new probe is efficiently evaporated and the resultant water vapor measured using a Lyman-alpha hygrometer. In airborne trials the device was calibrated against a cooled-mirror dewpoint device. Runs were conducted in warm stratocumulus tops, through small cumulus, in mixed-phase precipitation and cirrus cloud. In all cases the device was found to produce high quality, fast response data.

  20. A cost-effectiveness comparison of existing and Landsat-aided snow water content estimation systems

    NASA Technical Reports Server (NTRS)

    Sharp, J. M.; Thomas, R. W.

    1975-01-01

    This study describes how Landsat imagery can be cost-effectively employed to augment an operational hydrologic model. Attention is directed toward the estimation of snow water content, a major predictor variable in the volumetric runoff forecasting model presently used by the California Department of Water Resources. A stratified double sampling scheme is supplemented with qualitative and quantitative analyses of existing operations to develop a comparison between the existing and satellite-aided approaches to snow water content estimation. Results show a decided advantage for the Landsat-aided approach.

  1. Retrieving cloud ice water content and geometrical thickness from microwave and infrared radiometric observations

    NASA Technical Reports Server (NTRS)

    Wu, M.-L. C.

    1986-01-01

    Techniques are presented and their application illustrated for analysis of remotely sensed data collected with an aircraft carrying a multispectral cloud radiometer and an advanced microwave moisture sounder. The instruments were used on NASA high altitude flights to perform cloud field experiments. Sample IR and microwave brightness temperature data are provided as functions of the ice water path and of the ice water content. Quantitative models are described for deriving the cloud ice (or liquid) water content and the cloud geometric thickness from the radiometric data.

  2. Uranium contents and associated effective doses in drinking water from Biscay (Spain).

    PubMed

    Herranz, M; Abelairas, A; Legarda, F

    1997-06-01

    The determination of 234U and 238U content in drinking waters treated at four treatment plants supplying water to a set of municipalities located in northern Spain has given mean values of 1.14 mBq/L for 234U and 0.8 mBq/L for 238U. These contents, taking into account the population supplied with water and its distribution in age intervals, have allowed the determination of the annual intake of both radionuclides as well as the mean committed dose due to the ingestion of these radionuclides for which a value of 0.081 microSv/person is obtained.

  3. A cost-effectiveness comparison of existing and Landsat-aided snow water content estimation systems

    NASA Technical Reports Server (NTRS)

    Sharp, J. M.; Thomas, R. W.

    1975-01-01

    This study describes how Landsat imagery can be cost-effectively employed to augment an operational hydrologic model. Attention is directed toward the estimation of snow water content, a major predictor variable in the volumetric runoff forecasting model presently used by the California Department of Water Resources. A stratified double sampling scheme is supplemented with qualitative and quantitative analyses of existing operations to develop a comparison between the existing and satellite-aided approaches to snow water content estimation. Results show a decided advantage for the Landsat-aided approach.

  4. Metrologically Traceable Determination of the Water Content in Biopolymers: INRiM Activity

    NASA Astrophysics Data System (ADS)

    Rolle, F.; Beltramino, G.; Fernicola, V.; Sega, M.; Verdoja, A.

    2017-03-01

    Water content in materials is a key factor affecting many chemical and physical properties. In polymers of biological origin, it influences their stability and mechanical properties as well as their biodegradability. The present work describes the activity carried out at INRiM on the determination of water content in samples of a commercial starch-derived biopolymer widely used in shopping bags (Mater-Bi^{circledR }). Its water content, together with temperature, is the most influencing parameter affecting its biodegradability, because of the considerable impact on the microbial activity which is responsible for the biopolymer degradation in the environment. The main scope of the work was the establishment of a metrologically traceable procedure for the determination of water content by using two electrochemical methods, namely coulometric Karl Fischer (cKF) titration and evolved water vapour (EWV) analysis. The obtained results are presented. The most significant operational parameters were considered, and a particular attention was devoted to the establishment of metrological traceability of the measurement results by using appropriate calibration procedures, calibrated standards and suitable certified reference materials. Sample homogeneity and oven-drying temperature were found to be the most important influence quantities in the whole water content measurement process. The results of the two methods were in agreement within the stated uncertainties. Further development is foreseen for the application of cKF and EWV to other polymers.

  5. Progress In Methods Of Measuring The Free Water Content Of Snow

    NASA Astrophysics Data System (ADS)

    Fisk, David J.

    1983-09-01

    Providing ground truth for the backscatter and absorption effects of a snow cover on electromagnetic waves has long been a problem. One characteristic of the snow cover which has been particularly difficult to measure is its free, or liquid, water content - the fraction of the snow's volume which exists in the liquid state. Five methods which have been used for measuring this parameter are described and their merits and deficiencies discussed. Two of the methods are calorimetric, measuring the free water content as a function of the heat added to or removed from a snow sample while completely melting or freezing it. The third uses the freezing point depression observed on adding a salt solution to a snow sample to calculate the snow's free water content. In the fourth procedure, a snow sample is completely dissolved in ethyl or methyl alcohol. The corresponding decrease in temperature is inversely related to the free water content of the snow. The final technique is electronic: above a certain frequency, the electrical capacitance of snow is related to its density and free water content. With accurate calibration, devices which measure snow capacitance are likely to be the simplest and fastest means of providing free water measurements.

  6. Comparing electronic probes for volumetric water content of low-density feathermoss

    USGS Publications Warehouse

    Overduin, P.P.; Yoshikawa, K.; Kane, D.L.; Harden, J.W.

    2005-01-01

    Purpose - Feathermoss is ubiquitous in the boreal forest and across various land-cover types of the arctic and subarctic. A variety of affordable commercial sensors for soil moisture content measurement have recently become available and are in use in such regions, often in conjunction with fire-susceptibility or ecological studies. Few come supplied with calibrations suitable or suggested for soils high in organics. Aims to test seven of these sensors for use in feathermoss, seeking calibrations between sensor output and volumetric water content. Design/methodology/approach - Measurements from seven sensors installed in live, dead and burned feathermoss samples, drying in a controlled manner, were compared to moisture content measurements. Empirical calibrations of sensor output to water content were determined. Findings - Almost all of the sensors tested were suitable for measuring the moss sample water content, and a unique calibration for each sensor for this material is presented. Differences in sensor design lead to changes in sensitivity as a function of volumetric water content, affecting the spatial averaging over the soil measurement volume. Research limitations/implications - The wide range of electromagnetic sensors available include frequency and time domain designs with variations in wave guide and sensor geometry, the location of sensor electronics and operating frequency. Practical implications - This study provides information for extending the use of electromagnetic sensors to feathermoss. Originality/value - A comparison of volumetric water content sensor mechanics and design is of general interest to researchers measuring soil water content. In particular, researchers working in wetlands, boreal forests and tundra regions will be able to apply these results. ?? Emerald Group Publishing Limited.

  7. Quantification of seasonal biomass effects on cosmic-ray soil water content determination

    NASA Astrophysics Data System (ADS)

    Baatz, R.; Bogena, H. R.; Hendricks Franssen, H.; Huisman, J. A.; Qu, W.; Montzka, C.; Korres, W.; Vereecken, H.

    2013-12-01

    The novel cosmic-ray soil moisture probes (CRPs) measure neutron flux density close to the earth surface. High energy cosmic-rays penetrate the Earth's atmosphere from the cosmos and become moderated by terrestrial nuclei. Hydrogen is the most effective neutron moderator out of all chemical elements. Therefore, neutron flux density measured with a CRP at the earth surface correlates inversely with the hydrogen content in the CRP's footprint. A major contributor to the amount of hydrogen in the sensor's footprint is soil water content. The ability to measure changes in soil water content within the CRP footprint at a larger-than-point scale (~30 ha) and at high temporal resolution (hourly) make these sensors an appealing measurement instrument for hydrologic modeling purposes. Recent developments focus on the identification and quantification of major uncertainties inherent in CRP soil moisture measurements. In this study, a cosmic-ray soil moisture network for the Rur catchment in Western Germany is presented. It is proposed to correct the measured neutron flux density for above ground biomass yielding vegetation corrected soil water content from cosmic-ray measurements. The correction for above ground water equivalents aims to remove biases in soil water content measurements on sites with high seasonal vegetation dynamics such as agricultural fields. Above ground biomass is estimated as function of indices like NDVI and NDWI using regression equations. The regression equations were obtained with help of literature information, ground-based control measurements, a crop growth model and globally available data from the Moderate Resolution Imaging Spectrometer (MODIS). The results show that above ground biomass could be well estimated during the first half of the year. Seasonal changes in vegetation water content yielded biases in soil water content of ~0.05 cm3/cm3 that could be corrected for with the vegetation correction. The vegetation correction has particularly

  8. Origin and Distribution of Water Contents in Continental and Oceanic Lithospheric Mantle

    NASA Technical Reports Server (NTRS)

    Peslier, Anne H.

    2013-01-01

    The water content distribution of the upper mantle will be reviewed as based on the peridotite record. The amount of water in cratonic xenoliths appears controlled by metasomatism while that of the oceanic mantle retains in part the signature of melting events. In both cases, the water distribution is heterogeneous both with depth and laterally, depending on localized water re-enrichments next to melt/fluid channels. The consequence of the water distribution on the rheology of the upper mantle and the location of the lithosphere-asthenosphere boundary will also be discussed.

  9. Water Content, Raffinose, and Dehydrins in the Induction of Desiccation Tolerance in Immature Wheat Embryos

    PubMed Central

    Black, Michael; Corbineau, Françoise; Gee, Harry; Côme, Daniel

    1999-01-01

    Desiccation tolerance is initiated in wheat (Triticum aestivum L.) embryos in planta at 22 to 24 d after anthesis, at the time that the embryo water content has decreased from about 73% fresh weight (2.7 g water/g dry weight) to about 65% fresh weight (1.8 g water/g dry weight). To determine if desiccation tolerance is fully induced by the loss of a relatively small amount of water, detached wheat grains were treated to reduce the embryo water content by just a small amount to approximately 69% (2.2 g water/g dry weight). After 24 h of such incipient water loss, subsequently excised embryos were able to withstand severe desiccation, whereas those embryos that had not previously lost water could not. Therefore, a relatively small decrease in water content for only 24 h acts as the signal for the development of desiccation tolerance. Embryos that were induced into tolerance by a 24-h water loss had no detectable raffinose. The oligosaccharide accumulated at later times even in embryos of detached grains that had not become desiccation tolerant, although tolerant embryos (i.e. those that previously had lost some water) contained larger amounts of the carbohydrate. It is concluded that desiccation tolerance and the occurrence of raffinose are not correlated. Immunodetected dehydrins accumulated in embryos in planta as desiccation tolerance developed. Detachment of grains induced the appearance of dehydrins at an earlier age, even in embryos that had not been made desiccation tolerant by incipient drying. It is concluded that a small reduction in water content induces desiccation tolerance by initiating changes in which dehydrins might participate but not by their interaction with raffinose. PMID:10364397

  10. Water content influence on thermal and volumetric properties of wheat starch gelatinization under 10 MPa.

    PubMed

    Orlowska, Marta; Randzio, Stanislaw L

    2010-02-01

    A transitiometric in situ analysis of wheat starch aqueous suspensions heated over a temperature range from 285 K to 415 K under isobaric conditions of 10 MPa is presented. Measurements were performed at four selected water concentrations: 56.0%, 64.7%, 73.5%, and 82.4% weight/water. Thermal and volumetric properties and their water content dependencies have been determined for three successive starch phase transformations occurred during wheat starch gelatinization.

  11. Electro-Optical Transmission and Liquid Water Content of Fogs and Clouds

    DTIC Science & Technology

    1985-05-01

    ter Clouds. 1.3. Experimental Apparatus and Techniques 1.4. Liquid Water Content of laboratory Cloud 1.5. Data Acquisition 1.6 Experimental ...Backscatter in Water Cloud at Visible Wavelengths 2.6. Experimental Verification of the Extinction-Backscatter Relation at Visible Wavelengths 13...16 SECTION 3: EXTINCTION AND BACKSCATTER OF WATER CLOUDS AT CO. 1 LASER WAVELENGTHS 3.1. Introduction 3.2 Experimental Measurement of

  12. Relating x-ray attenuation measurements to water content and distribution in SB-15D core

    SciTech Connect

    Bonner, B.P.; Roberts, J.J.; Schneberk, D.J

    1996-09-30

    Making improved estimates of the water content of The Geysers reservoir is fundamental to efficient and economic long term production of steam power from the resource. A series of coordinated physical properties measurements form core recovered from the SB-15D, reported in this volume in a series of papers, have been made to better understand water storage and to relate water content and distribution to observable geophysical properties such as electrical conductivity and seismic velocities. A principal objective here is to report new interpretations of x-ray scans made within 72 hours of core recovery from SB-15D, which suggest, taking advantage of preliminary measurements of capillary suction for metagraywacke, that water content was low in much of the preserved core.

  13. Total Body Water Content of Neonates with Obstruction of Alimentary Tract

    PubMed Central

    Tsingoglou, Stavros; Phillips, Harriett; Wilkinson, Andrew W.

    1972-01-01

    The total body water content was measured by the deuterium oxide dilution method in 55 neonates admitted to hospital for surgical treatment within 90 hours of birth. The mean total body water of the whole group was 77·03 ± 0·62 (SEM)% of the body weight (range 67·4 to 88·6%), or 1·974 ± 0·005 (SEM) litres (range 1·010 to 2·830 litres). Over a range of body weights from 1·160 to 3·851 kg, total body water content expressed as a percentage of body weight decreased by 5% per kg rise in body weight, but when expressed as litres per kg body weight it increased by 737 ml for each rise of 1 kg in body weight. There was a small difference in water content between babies with obstruction of the alimentary tract and those with other nonobstructive lesions, which was not statistically significant. PMID:4567075

  14. Uncertainty in vertically integrated liquid water content due to radar reflectivity observation error

    NASA Technical Reports Server (NTRS)

    French, Mark N.; Andrieu, Herve; Krajewski, Witold F.

    1995-01-01

    Radar reflectivity is used to estimate meteorological quantities such as rainfall rate, liquid water content, and the related quantity, vertically integrated liquid (VIL) water content. The estimation of any of these quantities depends on several assumptions related to the characteristics of the physical processes controlling the occurrence and character of water in the atmosphere. Additionally, there are many sources of error associated with radar observations, such as those due to brighthand, hail, and drop size distribution approximations. This work addresses one error of interest, the radar reflectivity observation error; other error sources are assumed to be corrected or negligible. The result is a relationship between the uncertainty in VIL water content and radar reflectivity measurement error. An example application illustrates the estimation of VIL uncertainty from typical radar reflectivity observations and indicates that the coefficient of variation in VIL is much larger than the coefficient of variation in radar reflectivity.

  15. Determination of Henry’s Law Constants Using Internal Standards with Benchmark Values

    EPA Science Inventory

    It is shown that Henry’s law constants can be experimentally determined by comparing headspace content of compounds with known constants to interpolate the constants of other compounds. Studies were conducted over a range of water temperatures to identify temperature dependence....

  16. Determination of Henry’s Law Constants Using Internal Standards with Benchmark Values

    EPA Science Inventory

    It is shown that Henry’s law constants can be experimentally determined by comparing headspace content of compounds with known constants to interpolate the constants of other compounds. Studies were conducted over a range of water temperatures to identify temperature dependence....

  17. [Metallic content of water sources and drinkable water in industrial cities of Murmansk region].

    PubMed

    Doushkina, E V; Dudarev, A A; Sladkova, Yu N; Zachinskaya, I Yu; Chupakhin, V S; Goushchin, I V; Talykova, L V; Nikanov, A N

    2015-01-01

    Performed in 2013, sampling of centralized and noncentralized water-supply and analysis of engineering technology materials on household water use in 6 cities of Murmansk region (Nikel, Zapolyarny, Olenegorsk, Montchegorsk, Apatity, Kirovsk), subjected to industrial emissions, enabled to evaluate and compare levels of 15 metals in water sources (lakes and springs) and the cities' drinkable waters. Findings are that some cities lack sanitary protection zones for water sources, most cities require preliminary water processing, water desinfection involves only chlorination. Concentrations of most metals in water samples from all the cities at the points of water intake, water preparation and water supply are within the hygienic norms. But values significantly (2-5 times) exceeding MACs (both in water sources and in drinkable waters of the cities) were seen for aluminium in Kirovsk city and for nickel in Zapolarny and Nikel cities. To decrease effects of aluminium, nickel and their compounds in the three cities' residents (and preserve health of the population and offsprings), the authors necessitate specification and adaptation of measures to purify the drinkable waters from the pollutants. In all the cities studied, significantly increased concentrations of iron and other metals were seen during water transportation from the source to the city supply--that necessitates replacement of depreciated water supply systems by modern ones. Water taken from Petchenga region springs demonstrated relatively low levels of metals, except from strontium and barium.

  18. Dynamic factor analysis of surface water management impacts on soil and bedrock water contents in Southern Florida Lowlands

    NASA Astrophysics Data System (ADS)

    Kisekka, I.; Migliaccio, K. W.; Muñoz-Carpena, R.; Schaffer, B.; Li, Y. C.

    2013-04-01

    SummaryAs part of the C111 spreader canal project, structural and operational modifications involving incremental raises in canal stage are planned along one of the major canals (i.e., C111) separating Everglades National Park and agricultural production areas to the east of the park. This study used Dynamic Factor Analysis (DFA) as an alternative tool to physically based models to explore the relationship between different hydrologic variables and the effect of proposed changes in surface water management on soil and bedrock water contents in south Florida. To achieve the goal, objectives were to: (1) use DFA to identify the most important factors affecting temporal variation in soil and bedrock water contents, (2) develop a simplified DFA based regression model for predicting soil and bedrock water contents as a function of canal stage and (3) assess the effect of the proposed incremental raises in canal stage on soil and bedrock water contents. DFA revealed that five common trends were the minimum required to describe unexplained variation in the 11 time series studied. Introducing canal stage, water table evaporation and net recharge resulted in lower Akaike information criterion (AIC) and higher Nash-Sutcliffe (Ceff) values. Results indicated that canal stage significantly (t > 2) drives temporal variation in soil and bedrock water contents, which was represented as scaled frequency while net surface recharge was significant in seven out of the 11 time series analyzed. The effect of water table evaporation was not significant at all sites. Results also indicated that the most important factor influencing temporal variation in soil and bedrock water contents in terms of regression coefficient magnitude was canal stage. Based on DFA results, a simple regression model was developed to predict soil and bedrock water contents at various elevations as a function of canal stage and net recharge. The performance of the simple model ranged from good (Ceff ranging from

  19. Measuring the absolute water content of the brain using quantitative MRI.

    PubMed

    Shah, Nadim Joni; Ermer, Veronika; Oros-Peusquens, Ana-Maria

    2011-01-01

    Methods for quantitative imaging of the brain are presented and compared. Highly precise and accurate mapping of the absolute water content and distribution, as presented here, requires a significant number of corrections and also involves mapping of other MR parameters. Here, either T(1) and T(2)(*) or T(2) is mapped, and several corrections involving the measurement of temperature, transmit and receive B(1) inhomogeneities and signal extrapolation to zero TE are applied. Information about the water content of the whole brain can be acquired in clinically acceptable measurement times (10 or 20 min). Since water content is highly regulated in the healthy brain, pathological changes can be easily identified and their evolution or correlation with other manifestations of the disease investigated. In addition to voxel-based total water content, information about the different environments of water can be gleaned from qMRI. The myelin water fraction can be extracted from the fit of very high-SNR multiple-echo T(2) decay curves with a superposition of a large number of exponentials. Diseases involving de- or dysmyelination can be investigated and lead to novel observations regarding the water compartmentalisation in tissue, despite the limited spatial coverage. In conclusion, quantitative MRI is emerging as an unparalleled tool for the study of the normal and diseased brain, replacing the customary time-space environment of the sequential mixed-contrast MRI with a multi-NMR-parametric space in which tissue microscopy is increasingly revealed.

  20. Air-Liquid Partition Coefficient for a Diverse Set of Organic Compounds: Henry’s Law Constant in Water and Hexadecane

    EPA Science Inventory

    The SPARC vapor pressure and activity coefficient models were coupled to estimate Henry’s Law Constant (HLC) in water and in hexadecane for a wide range of non-polar and polar solute organic compounds without modification to/or additional parameterization of the vapor pressure or...

  1. Air-Liquid Partition Coefficient for a Diverse Set of Organic Compounds: Henry’s Law Constant in Water and Hexadecane

    EPA Science Inventory

    The SPARC vapor pressure and activity coefficient models were coupled to estimate Henry’s Law Constant (HLC) in water and in hexadecane for a wide range of non-polar and polar solute organic compounds without modification to/or additional parameterization of the vapor pressure or...

  2. Soil Water Cycling Links to Carbon Content between Ecosystems in the Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Powell, K. M.; Anderson, D. E.; Stannard, D. I.; Mladinich, C. S.; Thienelt, T. S.; Blanken, P.

    2011-12-01

    Near surface soil-water content is crucial to the sustainability of an ecosystem. Additionally, the feedbacks between soil water and soil carbon improve the ability to predict carbon sequestration rates. Organic-carbon content in surface soils influences soil texture and, subsequently, water holding capacity. Preliminary research for two growing seasons (2010 and 2011) compares soil water, temperature, heat flux, and evapotranspiration (ET) with soil organic carbon content at several sites in the Colorado Front Range. Continuous measurements of precipitation, soil moisture and temperature, and energy fluxes were conducted from eddy covariance flux towers at three sites around metropolitan Denver: one urban site and two adjacent sites, a montane forest (Flying J Ranch Open Space), and a native tallgrass prairie (Rocky Flats National Wildlife Refuge (NWR)). Irrigation data were obtained for the Denver urban site and added to its precipitation to obtain total water inputs. Soil samples (0-5cm) were collected at each tower site and analyzed for bulk density, volumetric water content, and organic carbon content. Soil water inputs and losses (as ET) were analyzed for each site and compared to soil organic carbon content. Rocky Flats NWR soils contained the highest organic carbon content (20-30 percent), while the urban site and Flying J Ranch soils contained between 10-15 percent. Comparing grassland sites, the urban soil received 5 times higher water input (600mm, more than half from irrigation) in 2010 than those of Rocky Flats. Despite less water input, the Rocky Flats site developed more soil organic carbon, possibly due to large amounts of grassland biomass mineralization and moderate soil moisture conditions through the season. The Denver urban site demonstrated less soil moisture variability in response to surface-water inputs from precipitation compared to soils at the native grassland and montane sites, perhaps limiting the conditions under which soil carbon

  3. Computation of porosity and water content from geophysical logs, Yucca Mountain, Nevada

    SciTech Connect

    Nelson, P.H.

    1996-12-31

    Neutron and density logs acquired in boreholes at Yucca Mountain, Nevada are used to determine porosity and water content as a function of depth. Computation of porosity requires an estimate of grain density, which is provided by core data, mineralogical data, or is inferred from rock type where neither core nor mineralogy are available. The porosity estimate is merged with mineralogical data acquired by X-ray diffraction to compute the volumetric fractions of major mineral groups. The resulting depth-based portrayal of bulk rock composition is equivalent to a whole rock analysis of mineralogy and porosity. Water content is computed from epithermal and thermal neutron logs. In the unsaturated zone, the density log is required along with a neutron log. Water content can also be computed from dielectric logs, which were acquired in only a fraction of the boreholes, whereas neutron logs were acquired in all boreholes. Mineralogical data are used to compute a structural (or bound) water estimate, which is subtracted from the total water estimate from the neutron-density combination. Structural water can be subtracted only from intervals where mineralogical analyses are available; otherwise only total water can be reported. The algorithms and procedures are applied to logs acquired during 1979 to 1984 at Yucca Mountain. Examples illustrate the results. Comparison between computed porosity and core measurements shows systematic differences ranging from 0.005 to 0.04. These values are consistent with a sensitivity analysis using uncertainty parameters for good logging conditions. Water content from core measurements is available in only one borehole, yielding a difference between computed and core-based water content of 0.006.

  4. Passive remote sensing of the atmospheric water vapour content above land surfaces

    NASA Astrophysics Data System (ADS)

    Bartsch, B.; Bakan, S.; Fischer, J.

    The global distribution of the atmospheric water vapour content plays an important role in the weather forecast and climate research. Nowadays there exist various methods dealing with remote sensing of the atmospheric water vapour content. Unfortunately, most of them are restricted to ocean areas, since, in general, the emission of land surfaces is not known well enough. Therefore, a new method is developed which allows the detection of the atmospheric total water vapour content from aircraft or satellite with the aid of backscattered solar radiation in the near infrared above land surfaces. The Matrix-Operator-Method has been used to simulate backscattered solar radiances, including various atmospheric profiles of temperature, pressure, water vapour, and aerosols of various types, several sun zenith angles, and different types of land surfaces. From these calculations it can be concluded, that the detection of water vapour content in cloudless atmospheres is possible with an error of < 10 % even for higher aerosol contents. In addition to the theoretical results first comparisons with aircraft measurements of the backscattered solar radiances are shown. These measurements have been carried out with the aid of OVID (Optical Visible and near Infrared Detector), a new multichannel array spectrometer, in 1993.

  5. Unsaturated flow characterization utilizing water content data collected within the capillary fringe

    USGS Publications Warehouse

    Baehr, Arthur; Reilly, Timothy J.

    2014-01-01

    An analysis is presented to determine unsaturated zone hydraulic parameters based on detailed water content profiles, which can be readily acquired during hydrological investigations. Core samples taken through the unsaturated zone allow for the acquisition of gravimetrically determined water content data as a function of elevation at 3 inch intervals. This dense spacing of data provides several measurements of the water content within the capillary fringe, which are utilized to determine capillary pressure function parameters via least-squares calibration. The water content data collected above the capillary fringe are used to calculate dimensionless flow as a function of elevation providing a snapshot characterization of flow through the unsaturated zone. The water content at a flow stagnation point provides an in situ estimate of specific yield. In situ determinations of capillary pressure function parameters utilizing this method, together with particle-size distributions, can provide a valuable supplement to data libraries of unsaturated zone hydraulic parameters. The method is illustrated using data collected from plots within an agricultural research facility in Wisconsin.

  6. Measuring Water Content and Desorption Isotherms in Soil Simulants Under Martian Conditions

    NASA Astrophysics Data System (ADS)

    Hudson, T.; Aharonson, O.; Schorghofer, N.; Hecht, M. H.; Bridges, N.; Green, J. R.

    2003-12-01

    Theoretical predictions as well as recent spacecraft observations indicate that large quantities of ice is present in the high latitudes upper decimeters to meters of the Martian regolith. At shallower depths and warmer locations small amounts of H2O, either adsorbed or free, may be present transiently. We seek to simulate Mars surface conditions and to observe the effects of temperature cycling (diurnal and seasonal scale) on the water content profiles of several soil simulants. To model the upper Martian regolith, we begin by using crushed JSC Mars-1 palagonite with particles in the 50 micron to sub-micron size range. Spheres of pure silica in the 10 to 40 mm range may also be used to study the effects of grain surface morphology and composition. Simulants with various water contents are brought to Mars pressures and monitored. A line source heat-pulse probe is being prepared to monitor water content profiles in real-time and to be calibrated against water content samples measured with thermogravimetric (TG) analysis. Initial experiments will allow us to monitor water content; more refined investigations will permit the determination of desorption isotherms.

  7. Pore-Scale Transport of Strontium During Dynamic Water Content Changes in the Unsaturated Zone

    NASA Astrophysics Data System (ADS)

    Weaver, W.; Kibbey, T. C. G.; Papelis, C.

    2016-12-01

    Dynamic water content changes in the unsaturated zone caused by natural and manmade processes, such as evaporation, rainfall, and irrigation, have an effect on contaminant mobility. In general, in the unsaturated zone, evaporation causes an increase in contaminant concentrations, potentially leading to sorption of contaminants on aquifer materials or precipitation of crystalline or amorphous phases. On the other hand, increase of water content may result in dissolution of precipitated phases and increased mobility of contaminants. The objective of this study was to develop a quantitative model for the transport of strontium through sand under dynamic water content conditions, as a function of strontium concentration, pH, and ionic strength. Strontium was selected as a surrogate for strontium-90, a by-product of nuclear reactions. The dynamic water content was determined using an automated device for rapidly measuring the hysteretic capillary pressure—saturation relationship, followed by ambient air evaporation, and gravimetric water content measurement. Strontium concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). Flow interruption experiments were conducted to determine whether equilibrium conditions existed for a given flowrate. Scanning electron microscopy (SEM) was used to visualize the treated quartz sand particles and the distribution of strontium on sand grains was determined using elemental maps created by energy-dispersive x-ray spectroscopy (EDX). Strontium behavior appears to be pH dependent as well as ionic strength dependent under these conditions.

  8. Monitoring of root zone water content in the lab by 2D geoelectrical tomography

    NASA Astrophysics Data System (ADS)

    Werban, U.; Al Hagrey, S. A.; Rabbel, W.

    2009-12-01

    Studying the simulation of plant behaviour under water stress conditions becomes more and more important as a consequence of the increasing water shortage in many countries. Therefore monitoring of soil moisture is essential to validate results of hydrological models and for balancing of water flow processes. One of the fundamental processes in this context is the root water uptake. Based on field studies we recognized the importance to observe the water content at different time steps. We present a method for monitoring soil water redistributions due to water uptake by roots. Our aim was to image and monitor diurnal soil water redistribution in a small scale indoor experiment (cm-dm range) using techniques of geoelectrical resistivity tomography of high resolution, and to correlate results of the applied geoelectrical time-lapse imaging techniques with single point TDR-method. The measured time-lapses were inverted in 2D resistivity models, which were transferred in moisture distributions within the root-zone and surrounding soils using a geophysical pedotransfer (pedophysical) function. The distribution of water content was observed over several weeks. We imaged significant heterogeneity of soil moisture in space and time, even whereas no irrigation was applied. We monitored highest moisture variability during the morning hours, whereas nearly no changes accrued during the night. In our presentation we will focus also on the development of a model for root zone media which has been established based on the Archie’s equation. Until now, the Archie equation has been applied successfully for granular media with full or partial water saturation (mixture of three phases: grain, water and air). However if roots are involved we have to consider a media of four phases (mixture of sand grain, water, air and root) The model of the electric resistivity versus water content for root zones has been validated by experimental laboratory data for fine sand with plant roots as

  9. Corneal tissue water content mapping with THz imaging: preliminary clinical results (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sung, Shijun; Bajwa, Neha; Deng, Sophie X.; Taylor, Zachary; Grundfest, Warren

    2016-03-01

    Well-regulated corneal water content is critical for ocular health and function and can be adversely affected by a number of diseases and injuries. Current clinical practice limits detection of unhealthy corneal water content levels to central corneal thickness measurements performed by ultrasound or optical coherence tomography. Trends revealing increasing or decreasing corneal thickness are fair indicators of corneal water content by individual measurements are highly inaccurate due to the poorly understood relationship between corneal thickness and natural physiologic variation. Recently the utility of THz imaging to accuarately measure corneal water content has been explored on with rabbit models. Preliminary experiments revealed that contact with dielectric windows confounded imaging data and made it nearly impossible to deconvolve thickness variations due to contact from thickness variations due to water content variation. A follow up study with a new optical design allowed the acquisition of rabbit data and the results suggest that the observed, time varying contrast was due entirely to the water dynamics of the cornea. This paper presents the first ever in vivo images of human cornea. Five volunteers with healthy cornea were recruited and their eyes were imaged three times over the course of a few minutes with our novel imaging system. Noticeable changes in corneal reflectivity were observed and attributed to the drying of the tear film. The results suggest that clinically compatible, non-contact corneal imaging is feasible and indicate that signal acquired from non-contact imaging of the cornea is a complicated coupling of stromal water content and tear film.

  10. Air-coupled ultrasonic resonant spectroscopy for the study of the relationship between plant leaves' elasticity and their water content.

    PubMed

    Sancho-Knapik, Domingo; Calás, Hector; Peguero-Pina, Jose Javier; Ramos Fernández, Antonio; Gil-Pelegrín, Eustaquio; Gómez Álvarez-Arenas, Tomas E

    2012-02-01

    Air-coupled wideband ultrasonic piezoelectric transducers are used in the frequency range 0.3 to 1.3 MHz to excite and sense first-order thickness resonances in the leaves of four different tree species at different levels of hydration. The phase and magnitude spectra of these resonances are measured, and the inverse problem solved; that is, leaf thickness and density, ultrasound velocity, and the attenuation coefficient are obtained. The elastic constant in the thickness direction (c33) is then determined from density and velocity data. The paper focuses on the study of c33, which provides a unique, fast, and noninvasive ultrasonic method to determine leaf elasticity and leaf water content.

  11. Assessing HYDRUS-2D model to estimate soil water contents and olive tree transpiration fluxes under different water distribution systems

    NASA Astrophysics Data System (ADS)

    Autovino, Dario; Negm, Amro; Rallo, Giovanni; Provenzano, Giuseppe

    2016-04-01

    In Mediterranean countries characterized by limited water resources for agricultural and societal sectors, irrigation management plays a major role to improve water use efficiency at farm scale, mainly where irrigation systems are correctly designed to guarantee a suitable application efficiency and the uniform water distribution throughout the field. In