Weak absorptions in high density planetary atmospheres measured by the cavity ring down technique.

NASA Astrophysics Data System (ADS)

Snels, M.; Stefani, S.; Piccioni, G.

2014-04-01

High density planetary atmospheres are characterized by a high opacity due to the strong absorbers. Howevere usually several transparency windows exist which allow to study the lower part of the atmosphere as well as the surface emission. The weak absorptions occurring in these transparency windows are mostly due to trace species and to continuum absorption of the major absorber(s). A good example is the atmosphere of Venus, where carbondioxide causes a high opacity throughout most of the infrared wavelengths, but also has some transparency spectral windows in the near infrared, allowing the study of low lying clouds , trace species such as water vapor and in some cases the surface emission. The cavity ring down (CRD) technique has shown to be a good tool for studying weak absorptions. Here we present a CRD apparatus which can be operated at high pressures (up to 40 bar) with a sensitivity which allows to measure attenuations up to 2x10-8 cm-1. This instrument has been used to measure the carbon dioxide absorption at pressures up to 40 bar and has been also used to measure attenuation due to Rayleigh scattering at 1.18 μm.

Electromagnetic-radiation absorption by water.

PubMed

Lunkenheimer, P; Emmert, S; Gulich, R; Köhler, M; Wolf, M; Schwab, M; Loidl, A

2017-12-01

Why does a microwave oven work? How does biological tissue absorb electromagnetic radiation? Astonishingly, we do not have a definite answer to these simple questions because the microscopic processes governing the absorption of electromagnetic waves by water are largely unclarified. This absorption can be quantified by dielectric loss spectra, which reveal a huge peak at a frequency of the exciting electric field of about 20 GHz and a gradual tailing off toward higher frequencies. The microscopic interpretation of such spectra is highly controversial and various superpositions of relaxation and resonance processes ascribed to single-molecule or molecule-cluster motions have been proposed for their analysis. By combining dielectric, microwave, THz, and far-infrared spectroscopy, here we provide nearly continuous temperature-dependent broadband spectra of water. Moreover, we find that corresponding spectra for aqueous solutions reveal the same features as pure water. However, in contrast to the latter, crystallization in these solutions can be avoided by supercooling. As different spectral contributions tend to disentangle at low temperatures, this enables us to deconvolute them when approaching the glass transition under cooling. We find that the overall spectral development, including the 20 GHz feature (employed for microwave heating), closely resembles the behavior known for common supercooled liquids. Thus water's absorption of electromagnetic waves at room temperature is not unusual but very similar to that of glass-forming liquids at elevated temperatures, deep in the low-viscosity liquid regime, and should be interpreted along similar lines.

Electromagnetic-radiation absorption by water

NASA Astrophysics Data System (ADS)

Lunkenheimer, P.; Emmert, S.; Gulich, R.; Köhler, M.; Wolf, M.; Schwab, M.; Loidl, A.

2017-12-01

Why does a microwave oven work? How does biological tissue absorb electromagnetic radiation? Astonishingly, we do not have a definite answer to these simple questions because the microscopic processes governing the absorption of electromagnetic waves by water are largely unclarified. This absorption can be quantified by dielectric loss spectra, which reveal a huge peak at a frequency of the exciting electric field of about 20 GHz and a gradual tailing off toward higher frequencies. The microscopic interpretation of such spectra is highly controversial and various superpositions of relaxation and resonance processes ascribed to single-molecule or molecule-cluster motions have been proposed for their analysis. By combining dielectric, microwave, THz, and far-infrared spectroscopy, here we provide nearly continuous temperature-dependent broadband spectra of water. Moreover, we find that corresponding spectra for aqueous solutions reveal the same features as pure water. However, in contrast to the latter, crystallization in these solutions can be avoided by supercooling. As different spectral contributions tend to disentangle at low temperatures, this enables us to deconvolute them when approaching the glass transition under cooling. We find that the overall spectral development, including the 20 GHz feature (employed for microwave heating), closely resembles the behavior known for common supercooled liquids. Thus water's absorption of electromagnetic waves at room temperature is not unusual but very similar to that of glass-forming liquids at elevated temperatures, deep in the low-viscosity liquid regime, and should be interpreted along similar lines.

Microwave absorption in substances that form hydration layers with water

NASA Astrophysics Data System (ADS)

Garner, H. R.; Ohkawa, T.; Tuason, O.; Lee, R. L.

1990-12-01

The microwave absorption of certain water soluble polymers (polyethylene glycol, polyvinyl pyrrolidone, proteins, and DNA) in solution is composed of three parts: absorption in the free water, absorption in the substance, and absorption in the hydration layer. Ethanol, sucrose, glycerol, and sodium acetate, which form weak hydrogen bonds or have an ionic nature in aqueous solutions, also have microwave absorption signatures similar to polymers that form hydration layers. The frequency-dependent absorption of the free water and of the hydration layer water is described by a simple Debye relaxation model. The absorption per unit sample volume attributable to the hydration layer is solute concentration dependent, and a simple model is used to describe the dependence. The hydration-layer relaxation time was found to vary from substance to substance and with solute concentration. The relaxation time was also found to be independent of solute length.

Influence of particle size on water absorption capacity and mechanical properties of polyethylene-wood flour composites

NASA Astrophysics Data System (ADS)

Zykova, A. K.; Pantyukhov, P. V.; Kolesnikova, N. N.; Popov, A. A.; Olkhov, A. A.

2015-10-01

Biocomposites based on low density polyethylene (LDPE) and birch wood flour (WF) were investigated. The mechanical properties and water absorption capacity were examined depending on the particle size of a filler in biocomposites. The aim of the paper is the investigation of composite properties depending on the filler particle size. The filler particle sizes were 0-80 µm, 80-140 µm, 140-200 µm, and 0-200 µm. The tensile strength of composite samples varied within the range 5.7-8.2 MPa. Elongation at break of composites varied within the range 5.1-7.5%. Highest mechanical properties were found in composites with the lowest filler fraction. Highest water absorption was observed in composition with a complex fraction of the filler. The influence of the filler particle size on composite properties was shown. It was found that an increase of the filler particle size decreases mechanical parameters and increases water absorption.

Absorption of water and lubricating oils into porous nylon

NASA Technical Reports Server (NTRS)

Bertrand, P. A.

1995-01-01

Oil and water absorption from air into sintered porous nylon can be described by infiltration into the pores of the material. This process can be modeled by a diffusion-like mechanism. For water absorption, we find a formal diffusion coefficient of 1.5 x 10(exp -4)sq cm/min when the nylon is initially dry. The diffusion coefficient is 4 x 10(exp -6)sq cm/min when the nylon is oil-impregnated prior to air exposure. In a 52% RH atmosphere, dry nylon absorbs 3% w/w water, and oil-impregnated nylon absorbs 0.6% w/w water. For oil absorption there are three steps: (1) surface absorption and infiltration into (2) larger and (3) smaller pores. Surface absorption is too fast to be measured in these experiments. The diffusion coefficient for the second step is 6 x 10(exp -4)sq cm/min for SRG-60 oil into dry nylon and 4 x 10(exp -4)sq cm/min for air-equilibrated nylon. The diffusion coefficient for the third step is about 1 x 10(exp -6)sq cm/min for both cases. The total amount of oil absorbed is 31% w/w. The interaction between water and nylon is not as strong as that between water and cotton-phenolic: oil can replace water, and only a small amount of water can enter previously oil-impregnated nylon.

Density Measurement for MORB Melts by X-ray Absorption Method

NASA Astrophysics Data System (ADS)

Sakamaki, T.; Urakawa, S.; Suzuki, A.; Ohtani, E.; Katayama, Y.

2006-12-01

Density of silicate melts at high pressure is one of the most important properties to understand magma migration in the planetary interior and the differentiation of the terrestrial planets. The density measurements of silicate melts have been carried out by several methods (shock compression experiments and sink-float method in static experiments, etc.). However, since these methods have difficulties in acquisition of data at a desired pressure and temperature, the density of the silicate melt have been measured under only a few conditions. Recently a new density measurement was developed by the X-ray absorption method. Advantage of this method is to measure density of liquids at a desired pressure and temperature. In the present study we measured the density of MORB melt by X-ray absorption method. Experiments were carried out at the BL22XU beamline at SPring-8. A DIA-type cubic anvil apparatus was used for generation of high pressure and temperature. We used tungsten carbide anvils with the top anvil sizes of 6 mm and 4 mm. The energy of monochromateized X-ray beam was 23 keV. The intensities of incident and transmitted X-ray were measured by ion chambers. The density of the melt was calculated on the basis of Beer-Lambert law. The starting material was a glass with the MORB composition. Experiments were made from 1 atm to 5 GPa, from 300 to 2000 K. We compared the density of MORB melt with the compression curve of the melt in previous works. The density measured by this study is lower than that expected from the compression curve determined at higher pressures by the sink-float method. Structural change of the MORB melt with increasing pressure might be attributed to this discrepancy.

Density Measurement for MORB Melts by X-ray Absorption Method

NASA Astrophysics Data System (ADS)

Sakamaki, T.; Urakawa, S.; Ohtani, E.; Suzuki, A.; Katayama, Y.

2005-12-01

Density of silicate melts at high pressure is one of the most important properties to understand magma migration in the planetary interior and the differentiation of the terrestrial planets. The density measurements of silicate melts have been carried out by several methods (shock compression experiments and sink-float method in static experiments, etc.). However, since these methods have difficulties in acquisition of data at a desired pressure and temperature, the density of the silicate melt have been measured under only a few conditions. Recently a new density measurement was developed by the X-ray absorption method. Advantage of this method is to measure density of liquids at a desired pressure and temperature. In the present study we measured the density of MORB melt by X-ray absorption method. Experiments were carried out at the BL22XU beamline at SPring-8. A DIA-type cubic anvil apparatus was used for generation of high pressure and temperature. We used tungsten carbide anvils with the edge-length of 6 mm. The energy of monochromateized X-ray beam was 23 keV. The intensities of incident and transmitted X-ray were measured by ion chambers. The density of the melt was calculated on the basis of Beer-Lambert law. The starting material was a glass with the MORB composition. Experiments were made from 1 atm to 4 GPa, from 300 to 2200 K. We compared the density of MORB melt with the compression curve of the melt in previous works. The density measured by this study is lower than that expected from the compression curve determined at higher pressures by the sink-float method. Structural change of the MORB melt with increasing pressure might be attributed to this discrepancy.

Absorption-Edge-Modulated Transmission Spectra for Water Contaminant Monitoring

DTIC Science & Technology

2016-03-31

Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6390--16-9675 Absorption-Edge-Modulated Transmission Spectra for Water Contaminant ...ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Absorption-Edge-Modulated Transmission Spectra for Water Contaminant Monitoring...Unlimited Unclassified Unlimited 35 Samuel G. Lambrakos (202) 767-2601 Monitoring of contaminants associated with specific water resources using

Effect of CO2 absorption on ion and water mobility in an anion exchange membrane

NASA Astrophysics Data System (ADS)

Peng, Jing; Roy, Asa L.; Greenbaum, Steve G.; Zawodzinski, Thomas A.

2018-03-01

We report the measured water uptake, density, ionic conductivity and water transport properties in Tokuyama A201 membrane in OH-, HCO3- and Cl- forms. The water uptake of the AEM varies with anion type in the order λ(OH-) > λ(HCO3-) > λ(Cl-) for samples equilibrated with the same water vapor activity (aw). The conductivity of the AEM is reduced by absorption of CO2. Pulsed-field gradient nuclear magnetic resonance (PFG-NMR) measurements were utilized to characterize the diffusivity of water and HCO3- ion. The anion diffusion coefficient and membrane conductivity are used to probe the applicability of the Nernst-Einstein equation in these AEMs.

Development of wavelength locking circuit for 1.53 micron water vapor monitoring coherent differential absorption LIDAR

NASA Astrophysics Data System (ADS)

Imaki, Masaharu; Kojima, Ryota; Kameyama, Shumpei

2018-04-01

We have studied a ground based coherent differential absorption LIDAR (DIAL) for vertical profiling of water vapor density using a 1.5μm laser wavelength. A coherent LIDAR has an advantage in daytime measurement compared with incoherent LIDAR because the influence of background light is greatly suppressed. In addition, the LIDAR can simultaneously measure wind speed and water vapor density. We had developed a wavelength locking circuit using the phase modulation technique and offset locking technique, and wavelength stabilities of 0.123 pm which corresponds to 16 MHz are realized. In this paper, we report the wavelength locking circuits for the 1.5 um wavelength.

Differential absorption lidar observation on small-time-scale features of water vapor in the atmospheric boundary layer

NASA Astrophysics Data System (ADS)

Kong, Wei; Li, Jiatang; Liu, Hao; Chen, Tao; Hong, Guanglie; Shu, Rong

2017-11-01

Observation on small-time-scale features of water vapor density is essential for turbulence, convection and many other fast atmospheric processes study. For the high signal-to-noise signal of elastic signal acquired by differential absorption lidar, it has great potential for all-day water vapor turbulence observation. This paper presents a set of differential absorption lidar at 935nm developed by Shanghai Institute of Technical Physics of the Chinese Academy of Science for water vapor turbulence observation. A case at the midday is presented to demonstrate the daytime observation ability of this system. "Autocovariance method" is used to separate the contribution of water vapor fluctuation from random error. The results show that the relative error is less than 10% at temporal and spatial resolution of 10 seconds and 60 meters in the ABL. This indicate that the system has excellent performance for daytime water vapor turbulence observation.

An effective way to reduce water absorption to terahertz

NASA Astrophysics Data System (ADS)

Wu, Yaxiong; Su, Bo; He, Jingsuo; Zhang, Cong; Zhang, Hongfei; Zhang, Shengbo; Zhang, Cunlin

2018-01-01

Since many vibrations and rotational levels of biomolecules fall within the THz band, THz spectroscopy can be used to identify biological samples. In addition, most biomolecules need to maintain their biological activity in a liquid environment, but water as polar substance has strong absorption to the THz wave. Thus, it is difficult to detect the sample information in aqueous solution using THz wave. In order to prevent the information of biological samples were masked in the solution, many research methods were used to explore how to reduce the water absorption of terahertz. In this paper, we have developed a real-time chemical methodology through transmission Terahertz time-domain spectroscopy (THz-TDS) system. The material of Zeonor 1020r is used as substrate and cover plate, and PDMS as channel interlayer. The transmission of the empty microfluidic chip is more than 80% in the range of 0.2-2.6 THz by THz-TDS system. Then, experiments were carried out using chips, which were filled with different volumes of 1, 2- propanediol, and it has been proved that the microfluidic chip could reduce the water absorption of terahertz. Finally, in order to further explore the reduction of terahertz to water absorption, we inject different concentrations of electrolyte to the chip. The results show that with the addition of different electrolytes, terahertz transmission line has evident changes. It can be taken into account that the electrolyte has different effects about the hydrogen bonds in the aqueous solution. Some of them can promote water molecules clusters, while others destroy them. Based on the basis of microfluidic chip, the discovery of this phenomenon can provide a way that reduces water absorption of terahertz. This work has laid a solid foundation for the subsequent study in reducing water absorption of terahertz.

Water Absorption in Galactic Translucent Clouds: Conditions and History of the Gas Derived from Herschel/HIFI PRISMAS Observations

NASA Astrophysics Data System (ADS)

Flagey, N.; Goldsmith, P. F.; Lis, D. C.; Gerin, M.; Neufeld, D.; Sonnentrucker, P.; De Luca, M.; Godard, B.; Goicoechea, J. R.; Monje, R.; Phillips, T. G.

2013-01-01

We present Herschel/HIFI observations of the three ground state transitions of H2O (556, 1669, and 1113 GHz) and H218O (547, 1655, and 1101 GHz)—as well as the first few excited transitions of H2O (987, 752, and 1661 GHz)—toward six high-mass star-forming regions, obtained as part of the PRISMAS (PRobing InterStellar Molecules with Absorption line Studies) Guaranteed Time Key Program. Water vapor associated with the translucent clouds in Galactic arms is detected in absorption along every line of sight in all the ground state transitions. The continuum sources all exhibit broad water features in emission in the excited and ground state transitions. Strong absorption features associated with the source are also observed at all frequencies except 752 GHz. We model the background continuum and line emission to infer the optical depth of each translucent cloud along the lines of sight. We derive the column density of H2O or H218O for the lower energy level of each transition observed. The total column density of water in translucent clouds is usually about a few 1013 cm-2. We find that the abundance of water relative to hydrogen nuclei is 1 × 10-8 in agreement with models for oxygen chemistry in which high cosmic ray ionization rates are assumed. Relative to molecular hydrogen, the abundance of water is remarkably constant through the Galactic plane with X(H2O) =5 × 10-8, which makes water a good traced of H2 in translucent clouds. Observations of the excited transitions of H2O enable us to constrain the abundance of water in excited levels to be at most 15%, implying that the excitation temperature, T ex, in the ground state transitions is below 10 K. Further analysis of the column densities derived from the two ortho ground state transitions indicates that T ex ~= 5 K and that the density n(H2) in the translucent clouds is below 104 cm-3. We derive the water ortho-to-para ratio for each absorption feature along the line of sight and find that most of the clouds

Atmospheric absorption of terahertz radiation and water vapor continuum effects

NASA Astrophysics Data System (ADS)

Slocum, David M.; Slingerland, Elizabeth J.; Giles, Robert H.; Goyette, Thomas M.

2013-09-01

The water vapor continuum absorption spectrum was investigated using Fourier Transform Spectroscopy. The transmission of broadband terahertz radiation from 0.300 to 1.500 THz was recorded for multiple path lengths and relative humidity levels. The absorption coefficient as a function of frequency was determined and compared with theoretical predictions and available water vapor absorption data. The prediction code is able to separately model the different parts of atmospheric absorption for a range of experimental conditions. A variety of conditions were accurately modeled using this code including both self and foreign gas broadening for low and high water vapor pressures for many different measurement techniques. The intensity and location of the observed absorption lines were also in good agreement with spectral databases. However, there was a discrepancy between the resonant line spectrum simulation and the observed absorption spectrum in the atmospheric transmission windows caused by the continuum absorption. A small discrepancy remained even after using the best available data from the literature to account for the continuum absorption. From the experimental and resonant line simulation spectra the air-broadening continuum parameter was calculated and compared with values available in the literature.

Multiband coherent perfect absorption in a water-based metasurface.

PubMed

Zhu, Weiren; Rukhlenko, Ivan D; Xiao, Fajun; He, Chong; Geng, Junping; Liang, Xianling; Premaratne, Malin; Jin, Ronghong

2017-07-10

We design an ultrathin water-based metasurface capable of coherent perfect absorption (CPA) at radio frequencies. It is demonstrated that such a metasurface can almost completely absorb two symmetrically incident waves within four frequency bands, each having its own modulation depth of metasurface absorptivity. Specifically, the absorptivity at 557.2 MHz can be changed between 0.59% and 99.99% via the adjustment of the phase difference between the waves. The high angular tolerance of our metasurface is shown to enable strong CPA at oblique incidence, with the CPA frequency almost independent of the incident angle for TE waves and varying from 557.2 up to 584.2 MHz for TM waves. One can also reduce this frequency from 712.0 to 493.3 MHz while retaining strong coherent absorption by varying the water layer thickness. It is also show that the coherent absorption performance can be flexibly controlled by adjusting the temperature of water. The proposed metasurface is low-cost, biocompatible, and useful for electromagnetic modulation and switching.

Molecular density functional theory of water including density-polarization coupling.

PubMed

Jeanmairet, Guillaume; Levy, Nicolas; Levesque, Maximilien; Borgis, Daniel

2016-06-22

We present a three-dimensional molecular density functional theory of water derived from first-principles that relies on the particle's density and multipolar polarization density and includes the density-polarization coupling. This brings two main benefits: (i) scalar density and vectorial multipolar polarization density fields are much more tractable and give more physical insight than the full position and orientation densities, and (ii) it includes the full density-polarization coupling of water, that is known to be non-vanishing but has never been taken into account. Furthermore, the theory requires only the partial charge distribution of a water molecule and three measurable bulk properties, namely the structure factor and the Fourier components of the longitudinal and transverse dielectric susceptibilities.

Scramjet Performance Assessment Using Water Absorption Diagnostics (U)

NASA Technical Reports Server (NTRS)

Cavolowsky, John A.; Loomis, Mark P.; Deiwert, George

1995-01-01

Simultaneous multiple path measurements of temperature and H2O concentration will be presented for the AIMHYE test entries in the NASA Ames 16-Inch Shock Tunnel. Monitoring the progress of high temperature chemical reactions that define scramjet combustor efficiencies is a task uniquely suited to nonintrusive optical diagnostics. One application strategy to overcome the many challenges and limitations of nonintrusive measurements is to use laser absorption spectroscopy coupled with optical fibers. Absorption spectroscopic techniques with rapidly tunable lasers are capable of making simultaneous measurements of mole fraction, temperature, pressure, and velocity. The scramjet water absorption diagnostic was used to measure combustor efficiency and was compared to thrust measurements using a nozzle force balance and integrated nozzle pressures to develop a direct technique for evaluating integrated scramjet performance. Tests were initially performed with a diode laser tuning over a water absorption feature at 1391.7 nm. A second diode laser later became available at a wavelength near 1343.3 nm covering an additional water absorption feature and was incorporated in the system for a two-wavelength technique. Both temperature and mole fraction can be inferred from the lineshape analysis using this approach. Additional high temperature spectroscopy research was conducted to reduce uncertainties in the scramjet application. The lasers are optical fiber coupled to ports at the combustor exit and in the nozzle region. The output from the two diode lasers were combined in a single fiber, and the resultant two-wavelength beam was subsequently split into four legs. Each leg was directed through 60 meters of optical fiber to four combustor exit locations for measurement of beam intensity after absorption by the water within the flow. Absorption results will be compared to 1D combustor analysis using RJPA and nozzle CFD computations as well as to data from a nozzle metric

Paper area density measurement from forward transmitted scattered light

DOEpatents

Koo, Jackson C.

2001-01-01

A method whereby the average paper fiber area density (weight per unit area) can be directly calculated from the intensity of transmitted, scattered light at two different wavelengths, one being a non-absorpted wavelength. Also, the method makes it possible to derive the water percentage per fiber area density from a two-wavelength measurement. In the optical measuring technique optical transmitted intensity, for example, at 2.1 microns cellulose absorption line is measured and compared with another scattered, optical transmitted intensity reference in the nearby spectrum region, such as 1.68 microns, where there is no absorption. From the ratio of these two intensities, one can calculate the scattering absorption coefficient at 2.1 microns. This absorption coefficient at this wavelength is, then, experimentally correlated to the paper fiber area density. The water percentage per fiber area density can be derived from this two-wavelength measurement approach.

Water Absorption Behavior of Hemp Hurds Composites

PubMed Central

Stevulova, Nadezda; Cigasova, Julia; Purcz, Pavol; Schwarzova, Ivana; Kacik, Frantisek; Geffert, Anton

2015-01-01

In this paper, water sorption behavior of 28 days hardened composites based on hemp hurds and inorganic binder was studied. Two kinds of absorption tests on dried cube specimens in deionized water bath at laboratory temperature were performed. Short-term (after one hour water immersion) and long-term (up to 180 days) water absorption tests were carried out to study their durability. Short-term water sorption behavior of original hemp hurds composites depends on mean particle length of hemp and on binder nature. The comparative study of long-term water sorption behavior of composites reinforced with original and chemically modified hemp hurds in three reagents confirmed that surface treatment of filler influences sorption process. Based on evaluation of sorption curves using a model for composites based on natural fibers, diffusion of water molecules in composite reinforced with original and chemically modified hemp hurds is anomalous in terms of the Fickian behavior. The most significant decrease in hydrophility of hemp hurds was found in case of hemp hurds modified by NaOH and it relates to change in the chemical composition of hemp hurds, especially to a decrease in average degree of cellulose polymerization as well as hemicellulose content.

Water absorption behaviour of hybrid interwoven cellulosic fibre composites

NASA Astrophysics Data System (ADS)

Maslinda, A. B.; Majid, M. S. Abdul; Ridzuan, M. J. M.; Syayuthi, AR. A.

2017-10-01

The present paper investigated the water absorption behaviour of hybrid interwoven cellulosic fibre composites. Hybrid composites consisting of interwoven kenaf/jute and kenaf/hemp yarns were prepared by an infusion manufacturing technique that used epoxy as the polymer matrix. Water absorption test was conducted as elucidated in ASTM D570 standard by immersing the composite samples in tap water at room temperature until reaching their water content saturation point. For each composite type, average from five samples was recorded and the percentage of water uptake against the square root of time was plotted. As the effect of hybridization, the water uptake, diffusion and permeability coefficient of the hybrid composites were lesser than the individual woven composites.

In Situ Density Measurement of Basaltic Melts at High Pressure by X-ray Absorption Method

NASA Astrophysics Data System (ADS)

Ando, R.; Ohtani, E.; Suzuki, A.; Urakawa, S.; Katayama, Y.

2004-12-01

Density of silicate melt at high pressure is one of the most important properties to understand magma migration in the planetary interior. However, because of experimental difficulties, the density of magma at high pressure is poorly known. Katayama et al. (1996) recently developed a new in situ density measurement method for metallic melts, based on the density dependency of X-ray absorption in the sample. In this study, we tried to measure the density of basaltic melt by this absorption method. When X-ray is transmitted to the sample, the intensity of the transmitted X-ray beam (I) is expressed as follows; I=I0exp(-μ ρ t), where I0 is the intensity of incident X-ray beam, μ is the mass absorption coefficient, ρ is the density of the sample, and t is the thickness of the sample. If t and μ are known, we can determine the density of the sample by measuring I and I0. This is the principle of the absorption method for density measurement. In this study, in order to determine t, we used a single crystalline diamond cylinder as a sample capsule, diamond is less compressive and less deformable so that even at high pressure t (thickness of the sample at the point x) is expressed as follows; t = 2*(R02-x2)1/2, R0 is the inner radius of cylinder at the ambient condition, and x is distance from a center of the capsule. And diamond also shows less absorption so that this make it possible to measure the density of silicate melt with smaller absorption coefficient than metallic melts. In order to know the μ of the sample, we measured both densities (ρ ) and absorptions (I/I0) for some glasses and crystals with same composition of the sample at the ambient condition, and calculated as fallows; μ =ln(I/I0)/ρ . Experiments were made at the beamline (BL22XU) of SPring-8. For generation of high pressure and high temperature, we used DIA-type cubic anvil apparatus (SMAP180) there. We used tungsten carbide anvils with the edge-length of 6 mm. The energy of monochromatic X

Density of alkaline magmas at crustal and upper mantle conditions by X-ray absorption

NASA Astrophysics Data System (ADS)

Seifert, R.; Malfait, W.; Petitgirard, S.; Sanchez-Valle, C.

2011-12-01

Silicate melts are essential components of igneous processes and are directly involved in differentiation processes and heat transfer within the Earth. Studies of the physical properties of magmas (e.g., density, viscosity, conductivity, etc) are however challenging and experimental data at geologically relevant pressure and temperature conditions remain scarce. For example, there is virtually no data on the density at high pressure of alkaline magmas (e.g., phonolites) typically found in continental rift zone settings. We present in situ density measurements of alkaline magmas at crustal and upper mantle conditions using synchrotron X-ray absorption. Measurements were conducted on ID27 beamline at ESRF using a panoramic Paris-Edinburgh Press (PE Press). The starting material is a synthetic haplo-phonolite glass similar in composition to the Plateau flood phonolites from the Kenya rift [1]. The glass was synthesized at 1673 K and 2.0 GPa in a piston-cylinder apparatus at ETH Zurich and characterized using EPMA, FTIR and density measurements. The sample contains less than 200 ppm water and is free of CO2. Single-crystal diamond cylinders (Øin = 0.5 mm, height = 1 mm) were used as sample containers and placed in an assembly formed by hBN spacers, a graphite heater and a boron epoxy gasket [2]. The density was determined as a function of pressure (1.0 to 3.1 GPa) and temperature (1630-1860 K) from the X-ray absorption contrast at 20 keV between the sample and the diamond capsule. The molten state of the sample during the data collection was confirmed by X-ray diffraction measurements. Pressure and temperature were determined simultaneously from the equation of state of hBN and platinum using the the double isochor method [3].The results are combined with available density data at room conditions to derive the first experimental equation of state (EOS) of phonolitic liquids at crustal and upper mantle conditions. We will compare our results with recent reports of the

A variable-density absorption event in NGC 3227 mapped with Suzaku and Swift

NASA Astrophysics Data System (ADS)

Beuchert, T.; Markowitz, A. G.; Krauß, F.; Miniutti, G.; Longinotti, A. L.; Guainazzi, M.; de La Calle Pérez, I.; Malkan, M.; Elvis, M.; Miyaji, T.; Hiriart, D.; López, J. M.; Agudo, I.; Dauser, T.; Garcia, J.; Kreikenbohm, A.; Kadler, M.; Wilms, J.

2015-12-01

Context. The morphology of the circumnuclear gas accreting onto supermassive black holes in Seyfert galaxies remains a topic of much debate. As the innermost regions of active galactic nuclei (AGN) are spatially unresolved, X-ray spectroscopy, and in particular line-of-sight absorption variability, is a key diagnostic to map out the distribution of gas. Aims: Observations of variable X-ray absorption in multiple Seyferts and over a wide range of timescales indicate the presence of clumps/clouds of gas within the circumnuclear material. Eclipse events by clumps transiting the line of sight allow us to explore the properties of the clumps over a wide range of radial distances from the optical/UV broad line region (BLR) to beyond the dust sublimation radius. Time-resolved absorption events have been extremely rare so far, but suggest a range of density profiles across Seyferts. We resolve a weeks-long absorption event in the Seyfert NGC 3227. Methods: We examine six Suzaku and 12 Swift observations from a 2008 campaign spanning five weeks. We use a model accounting for the complex spectral interplay of three absorbers with different levels of ionization. We perform time-resolved spectroscopy to discern the absorption variability behavior. We also examine the IR to X-ray spectral energy distribution (SED) to test for reddening by dust. Results: The 2008 absorption event is due to moderately-ionized (log ξ ~ 1.2-1.4) gas covering 90% of the line of sight. We resolve the density profile to be highly irregular, in contrast to a previous symmetric and centrally-peaked event mapped with RXTE in the same object. The UV data do not show significant reddening, suggesting that the cloud is dust-free. Conclusions: The 2008 campaign has revealed a transit by a filamentary, moderately-ionized cloud of variable density that is likely located in the BLR, and possibly part of a disk wind.

Water-based metamaterial absorbers for optical transparency and broadband microwave absorption

NASA Astrophysics Data System (ADS)

Pang, Yongqiang; Shen, Yang; Li, Yongfeng; Wang, Jiafu; Xu, Zhuo; Qu, Shaobo

2018-04-01

Naturally occurring water is a promising candidate for achieving broadband absorption. In this work, by virtue of the optically transparent character of the water, the water-based metamaterial absorbers (MAs) are proposed to achieve the broadband absorption at microwave frequencies and optical transparence simultaneously. For this purpose, the transparent indium tin oxide (ITO) and polymethyl methacrylate (PMMA) are chosen as the constitutive materials. The water is encapsulated between the ITO backed plate and PMMA, serving as the microwave loss as well as optically transparent material. Numerical simulations show that the broadband absorption with the efficiency over 90% in the frequency band of 6.4-30 GHz and highly optical transparency of about 85% in the visible region can be achieved and have been well demonstrated experimentally. Additionally, the proposed water-based MA displays a wide-angle absorption performance for both TE and TM waves and is also robust to the variations of the structure parameters, which is much desired in a practical application.

Intestinal absorption of water-soluble vitamins in health and disease.

PubMed

Said, Hamid M

2011-08-01

Our knowledge of the mechanisms and regulation of intestinal absorption of water-soluble vitamins under normal physiological conditions, and of the factors/conditions that affect and interfere with theses processes has been significantly expanded in recent years as a result of the availability of a host of valuable molecular/cellular tools. Although structurally and functionally unrelated, the water-soluble vitamins share the feature of being essential for normal cellular functions, growth and development, and that their deficiency leads to a variety of clinical abnormalities that range from anaemia to growth retardation and neurological disorders. Humans cannot synthesize water-soluble vitamins (with the exception of some endogenous synthesis of niacin) and must obtain these micronutrients from exogenous sources. Thus body homoeostasis of these micronutrients depends on their normal absorption in the intestine. Interference with absorption, which occurs in a variety of conditions (e.g. congenital defects in the digestive or absorptive system, intestinal disease/resection, drug interaction and chronic alcohol use), leads to the development of deficiency (and sub-optimal status) and results in clinical abnormalities. It is well established now that intestinal absorption of the water-soluble vitamins ascorbate, biotin, folate, niacin, pantothenic acid, pyridoxine, riboflavin and thiamin is via specific carrier-mediated processes. These processes are regulated by a variety of factors and conditions, and the regulation involves transcriptional and/or post-transcriptional mechanisms. Also well recognized now is the fact that the large intestine possesses specific and efficient uptake systems to absorb a number of water-soluble vitamins that are synthesized by the normal microflora. This source may contribute to total body vitamin nutrition, and especially towards the cellular nutrition and health of the local colonocytes. The present review aims to outline our current

Intestinal absorption of water-soluble vitamins in health and disease

PubMed Central

Said, Hamid M.

2014-01-01

Our knowledge of the mechanisms and regulation of intestinal absorption of water-soluble vitamins under normal physiological conditions, and of the factors/conditions that affect and interfere with theses processes has been significantly expanded in recent years as a result of the availability of a host of valuable molecular/cellular tools. Although structurally and functionally unrelated, the water-soluble vitamins share the feature of being essential for normal cellular functions, growth and development, and that their deficiency leads to a variety of clinical abnormalities that range from anaemia to growth retardation and neurological disorders. Humans cannot synthesize water-soluble vitamins (with the exception of some endogenous synthesis of niacin) and must obtain these micronutrients from exogenous sources. Thus body homoeostasis of these micronutrients depends on their normal absorption in the intestine. Interference with absorption, which occurs in a variety of conditions (e.g. congenital defects in the digestive or absorptive system, intestinal disease/resection, drug interaction and chronic alcohol use), leads to the development of deficiency (and sub-optimal status) and results in clinical abnormalities. It is well established now that intestinal absorption of the water-soluble vitamins ascorbate, biotin, folate, niacin, pantothenic acid, pyridoxine, riboflavin and thiamin is via specific carrier-mediated processes. These processes are regulated by a variety of factors and conditions, and the regulation involves transcriptional and/or post-transcriptional mechanisms. Also well recognized now is the fact that the large intestine possesses specific and efficient uptake systems to absorb a number of water-soluble vitamins that are synthesized by the normal microflora. This source may contribute to total body vitamin nutrition, and especially towards the cellular nutrition and health of the local colonocytes. The present review aims to outline our current

Water metamaterial for ultra-broadband and wide-angle absorption.

PubMed

Xie, Jianwen; Zhu, Weiren; Rukhlenko, Ivan D; Xiao, Fajun; He, Chong; Geng, Junping; Liang, Xianling; Jin, Ronghong; Premaratne, Malin

2018-02-19

A subwavelength water metamaterial is proposed and analyzed for ultra-broadband perfect absorption at microwave frequencies. We experimentally demonstrate that this metamaterial shows over 90% absorption within almost the entire frequency band of 12-29.6 GHz. It is also shown that the proposed metamaterial exhibits a good thermal stability with its absorption performance almost unchanged for the temperature range from 0 to 100°C. The study of the angular tolerance of the metamaterial absorber shows its ability of working at wide angles of incidence. Given that the proposed water metamaterial absorber is low-cost and easy for manufacture, we envision it may find numerous applications in electromagnetics such as broadband scattering reduction and electromagnetic energy harvesting.

The influence of water mixtures on the dermal absorption of glycol ethers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Traynor, Matthew J.; Wilkinson, Simon C.; Williams, Faith M.

2007-01-15

Glycol ethers are solvents widely used alone and as mixtures in industrial and household products. Some glycol ethers have been shown to have a range of toxic effects in humans following absorption and metabolism to their aldehyde and acid metabolites. This study assessed the influence of water mixtures on the dermal absorption of butoxyethanol and ethoxyethanol in vitro through human skin. Butoxyethanol penetrated human skin up to sixfold more rapidly from aqueous solution (50%, 450 mg/ml) than from the neat solvent. Similarly penetration of ethoxyethanol was increased threefold in the presence of water (50%, 697 mg/ml). There was a correspondingmore » increase in apparent permeability coefficient as the glycol ether concentration in water decreased. The maximum penetration rate of water also increased in the presence of both glycol ethers. Absorption through a synthetic membrane obeyed Fick's Law and absorption through rat skin showed a similar profile to human skin but with a lesser effect. The mechanisms for this phenomenon involves disruption of the stratum corneum lipid bilayer by desiccation by neat glycol ether micelles, hydration with water mixtures and the physicochemical properties of the glycol ether-water mixtures. Full elucidation of the profile of absorption of glycol ethers from mixtures is required for risk assessment of dermal exposure. This work supports the view that risk assessments for dermal contact scenarios should ideally be based on absorption data obtained for the relevant formulation or mixture and exposure scenario and that absorption derived from permeability coefficients may be inappropriate for water-miscible solvents.« less

[Spectral absorption properties of the water constituents in the estuary of Zhujiang River].

PubMed

Wang, Shan-shan; Wang, Yong-bo; Fu, Qing-hua; Yin, Bin; Li, Yun-mei

2014-12-01

Spectral absorption properties of the water constituents is the main factor affecting the light field under the surface of the water and the spectrum above the surface of the water. Thus, the study is useful for understanding of the water spectral property and the remote reversing of water quality parameters. Absorption properties of total suspended particles, non-algal particles, phytoplankton and CDOM were analyzed using the 30 samples collected in July 2013 in the estuary of Zhujiang River. The results indicated that: (1) the non-algal particles absorption dominated the absorption of the total suspended particles; (2) the absorption coefficient of the non-algal particles, which mainly came from the terrigenous deposits, decreased exponentially from short to long wavelength. In addition, the average value and spatial variation of the slope S(d) were higher than those in inland case- II waters; (3) the absorption coefficient of phytoplankton in 440 nm showed a better polynomial relationship with chlorophyll a concentration, while the absorption coefficient of phytoplankton in 675 nm linearly related with the chlorophyll a concentration. Moreover, the influence of accessory pigments on phytoplankton absorption coefficient mainly existed in the range of short wavelength, and Chlorophyll a was the main influencing factor for phytoplankton absorption in long wavelength. The specific absorption coefficient of phytoplankton decreased the power exponentially with the increase of the chlorophyll a concentration; (4) CDOM mainly came from the terrigenous sources and its spectral curve had an absorption shoulder between 250-290 nm. Thus, a piecewise S(g) fitting function could effectively express CDOM absorption properties, i.e., M value and S(g) value in period A (240-260 nm) showed a strong positive correlation. The M value was low, and the humic acid had a high proportion in CDOM; (5) the non-algal particles absorption dominated the total absorption in the estuary of

Effect of water absorption on the mechanical properties of poly(3-hydroxybutyrate)/vegetable fiber composites

NASA Astrophysics Data System (ADS)

Marinho, Vithória A. D.; Carvalho, Laura H.; Canedo, Eduardo L.

2015-05-01

The present work studies the effect of water absorption on the performance of composites of poly(3-hydroxybutyrate) (PHB) - a fully biodegradable semi-crystalline thermoplastic obtained from renewable resources through low-impact biotechnological process, biocompatible and non-toxic - and vegetable fiber from the fruit (coconut) of babassu palm tree.Water resistance is an important characteristic of structural composites, that may exposed to rain and humid environments. Both water absorption capacity (water solubility in the material) and the rate of water absorption (controlled by the diffusivity of water in the material) are important parameters. However, water absorption per se may not be the most important characteristic, insofar as the performance and applications of the compounds. It is the effect of the water content on the ultimate properties that determine the suitability of the material for applications that involve prolonged exposure to water.PHB/babassu composites with 0-20% load were prepared in an internal mixer. Two different types of babassu fibers having two different article size ranges were compounded with PHB and test specimens molded by compression. The water absorption capacity and the kinetic constant of water absorption were measured in triplicate. Mechanical properties under tension were measured for dry and moist specimens with different amounts of absorbed water.Results indicate that the performance of the composites is comparable to that of the pure matrix. Water absorption capacity increases from 0.7% (pure PHB) to 4% (PHB/20% babassu), but the water diffusivity (4.10□8 cm2/s) was found to be virtually independent of the water absorption level. Water absorption results in moderate drop in elastic modulus (10-30% at saturation, according to fiber content) but has little effect on tensile strength and elongation at break. Fiber type and initial particle size do not have a significant effect on water absorption or mechanical properties.

Bacterial carbonate precipitation improves water absorption of interlocking compressed earth block (ICEB)

NASA Astrophysics Data System (ADS)

Zamer, M. M.; Irwan, J. M.; Othman, N.; Faisal, S. K.; Anneza, L. H.; Alshalif, A. F.; Teddy, T.

2017-11-01

Interlocking compressed earth blocks (ICEB) are soil based blocks that allows for mortarless construction. The addition of many alternative materials into interlocking block in order to improve the durability has been reported. However there are currently lack of report and evidence on the application of biocalcification or microbiologically induced calcite precipitation (MICP) in improving the engineering properties of ICEB. This paper evaluate the effect of UB in improving the water absorption properties of ICEB. This paper also provide the results on SEM analysis of addition of 1%, 3% and 5% UB in ICEB. The bacteria were added as partial replacement of limestone water in ICEB. The results showed the reduction of 14.72% with 5% UB on initial water absorption followed by the results for water absorption by 24-hour soaking which also indicates reduction of 14.68% with 5% UB on 28th days of testing compared to control specimen. It was expected that the reduction of water absorption was due to the plugging of pores by the bacterial calcite which prevent ingression of water in ICEB samples. Therefore this study hopes that the positive results from the UB as improving in water absorption of ICEB will lead to improve others ICEB properties and others construction materials.

Analyzing Water's Optical Absorption

NASA Technical Reports Server (NTRS)

2002-01-01

A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.

Absorption spectra of deuterated water at DF laser wavelengths.

PubMed

Bruce, C W; Jelinek, A V

1982-11-15

Absorption coefficients for deuterated water have been measured at twenty-two deuterium fluoride (DF) laser wavelengths and presented for atmospheric conditions classified as midlatitude-summer (14.3 T water vapor, standard temperature, and pressure). The HDO vapor was produced from a liquid mixture of H(2)O and D(2)O. The proportions of the resulting equilibrium mixture involving these constituents and HDO were calculated using previously measured constants and produced strong HDO absorption at the 3.5-4.1-microm DF laser wavelengths relative to those of the H(2)O and D(2)O vapors. Predicted and measured pressure dependencies at constant mixing ratios are compared for several laser wavelengths having strong HDO absorption. Absorption coefficients are in fairly close agreement with those of the current Air Force Geophysical Laboratory line-by-line model for standard temperature and pressure conditions. At lower total pressures, the comparison is less satisfactory and suggests inaccurate line parameters in the predictive data base.

Specific absorption and backscatter coefficient signatures in southeastern Atlantic coastal waters

NASA Astrophysics Data System (ADS)

Bostater, Charles R., Jr.

1998-12-01

Measurements of natural water samples in the field and laboratory of hyperspectral signatures of total absorption and reflectance were obtained using long pathlength absorption systems (50 cm pathlength). Water was sampled in Indian River Lagoon, Banana River and Port Canaveral, Florida. Stations were also occupied in near coastal waters out to the edge of the Gulf Stream in the vicinity of Kennedy Space Center, Florida and estuarine waters along Port Royal Sound and along the Beaufort River tidal area in South Carolina. The measurements were utilized to calculate natural water specific absorption, total backscatter and specific backscatter optical signatures. The resulting optical cross section signatures suggest different models are needed for the different water types and that the common linear model may only appropriate for coastal and oceanic water types. Mean particle size estimates based on the optical cross section, suggest as expected, that particle size of oceanic particles are smaller than more turbid water types. The data discussed and presented are necessary for remote sensing applications of sensors as well as for development and inversion of remote sensing algorithms.

Terahertz sensing of highly absorptive water-methanol mixtures with multiple resonances in metamaterials.

PubMed

Chen, Min; Singh, Leena; Xu, Ningning; Singh, Ranjan; Zhang, Weili; Xie, Lijuan

2017-06-26

Terahertz sensing of highly absorptive aqueous solutions remains challenging due to strong absorption of water in the terahertz regime. Here, we experimentally demonstrate a cost-effective metamaterial-based sensor integrated with terahertz time-domain spectroscopy for highly absorptive water-methanol mixture sensing. This metamaterial has simple asymmetric wire structures that support multiple resonances including a fundamental Fano resonance and higher order dipolar resonance in the terahertz regime. Both the resonance modes have strong intensity in the transmission spectra which we exploit for detection of the highly absorptive water-methanol mixtures. The experimentally characterized sensitivities of the Fano and dipole resonances for the water-methanol mixtures are found to be 160 and 305 GHz/RIU, respectively. This method provides a robust route for metamaterial-assisted terahertz sensing of highly absorptive chemical and biochemical materials with multiple resonances and high accuracy.

Absorption coefficients for water vapor at 193 nm from 300 to 1073 K

NASA Technical Reports Server (NTRS)

Kessler, W. J.; Carleton, K. L.; Marinelli, W. J.

1993-01-01

Measurements of the water absorption coefficient at 193 nm from 300 to 1073 K are reported. The measurements were made using broadband VUV radiation and a monochromator-based detection system. The water vapor was generated by a saturator and metered into a flowing, 99 cm absorption cell via a water vapor mass flow meter. The 193 nm absorption coefficient measurements are compared to room temperature and high temperature shock tube measurements with good agreement. The absorption can be parameterized by a nu3 vibrational mode reaction coordinate and the thermal population of the nu3 mode.

Dynamics of Water Absorption and Evaporation During Methanol Droplet Combustion in Microgravity

NASA Technical Reports Server (NTRS)

Hicks, Michael C.; Dietrich, Daniel L.; Nayagam, Vedha; Williams, Forman A.

2012-01-01

The combustion of methanol droplets is profoundly influenced by the absorption and evaporation of water, generated in the gas phase as a part of the combustion products. Initially there is a water-absorption period of combustion during which the latent heat of condensation of water vapor, released into the droplet, enhances its burning rate, whereas later there is a water-evaporation period, during which the water vapor reduces the flame temperature suffciently to extinguish the flame. Recent methanol droplet-combustion experiments in ambient environments diluted with carbon dioxide, conducted in the Combustion Integrated Rack on the International Space Station (ISS), as a part of the FLEX project, provided a method to delineate the water-absorption period from the water-evaporation period using video images of flame intensity. These were obtained using an ultra-violet camera that captures the OH* radical emission at 310 nm wavelength and a color camera that captures visible flame emission. These results are compared with results of ground-based tests in the Zero Gravity Facility at the NASA Glenn Research Center which employed smaller droplets in argon-diluted environments. A simplified theoretical model developed earlier correlates the transition time at which water absorption ends and evaporation starts. The model results are shown to agree reasonably well with experiment.

Measurement of water absorption capacity in wheat flour by a headspace gas chromatographic technique.

PubMed

Xie, Wei-Qi; Yu, Kong-Xian; Gong, Yi-Xian

2018-04-17

The purpose of this work is to introduce a new method for quantitatively analyzing water absorption capacity in wheat flour by a headspace gas chromatographic technique. This headspace gas chromatographic technique was based on measuring the water vapor released from a series of wheat flour samples with different contents of water addition. According to the different trends between the vapor and wheat flour phase before and after the water absorption capacity in wheat flour, a turning point (corresponding to water absorption capacity in wheat flour) can be obtained by fitting the data of the water gas chromatography peak area from different wheat flour samples. The data showed that the phase equilibrium in the vial can be achieved in 25 min at desired temperature (35°C). The relative standard deviation of the reaction headspace gas chromatographic technique in water absorption capacity determination was within 3.48%, the relative differences has been determined by comparing the water absorption capacity obtained from this new analytical technique with the data from the reference technique (i.e., the filtration method), which are less than 8.92%. The new headspace gas chromatographic method is automated, accurate and be a reliable tool for quantifying water absorption capacity in wheat flour in both laboratory research and mill applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methods for analysis of selected metals in water by atomic absorption

USGS Publications Warehouse

Fishman, Marvin J.; Downs, Sanford C.

1966-01-01

This manual describes atomic-absorption-spectroscopy methods for determining calcium, copper, lithium, magnesium, manganese, potassium, sodium, strontium and zinc in atmospheric precipitation, fresh waters, and brines. The procedures are intended to be used by water quality laboratories of the Water Resources Division of the U.S. Geological Survey. Detailed procedures, calculations, and methods for the preparation of reagents are given for each element along with data on accuracy, precision, and sensitivity. Other topics discussed briefly are the principle of atomic absorption, instrumentation used, and special analytical techniques.

Atmospheric Precorrected Differential Absorption technique to retrieve columnar water vapor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlaepfer, D.; Itten, K.I.; Borel, C.C.

1998-09-01

Differential absorption techniques are suitable to retrieve the total column water vapor contents from imaging spectroscopy data. A technique called Atmospheric Precorrected Differential Absorption (APDA) is derived directly from simplified radiative transfer equations. It combines a partial atmospheric correction with a differential absorption technique. The atmospheric path radiance term is iteratively corrected during the retrieval of water vapor. This improves the results especially over low background albedos. The error of the method for various ground reflectance spectra is below 7% for most of the spectra. The channel combinations for two test cases are then defined, using a quantitative procedure, whichmore » is based on MODTRAN simulations and the image itself. An error analysis indicates that the influence of aerosols and channel calibration is minimal. The APDA technique is then applied to two AVIRIS images acquired in 1991 and 1995. The accuracy of the measured water vapor columns is within a range of {+-}5% compared to ground truth radiosonde data.« less

Equilibrium Structures and Absorption Spectra for SixOy-nH2O Molecular Clusters using Density Functional Theory

DTIC Science & Technology

2017-05-04

Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6390--17-9723 Equilibrium Structures and Absorption Spectra for SixOy-nH2O Molecular...Absorption Spectra for SixOy-nH2O Molecular Clusters using Density Functional Theory L. Huang, S.G. Lambrakos, and L. Massa1 Naval Research Laboratory, Code...and time-dependent density functional theory (TD-DFT). The size of the clusters considered is relatively large compared to those considered in

Pressure-Sensitive and Conductive Carbon Aerogels from Poplars Catkins for Selective Oil Absorption and Oil/Water Separation.

PubMed

Li, Lingxiao; Hu, Tao; Sun, Hanxue; Zhang, Junping; Wang, Aiqin

2017-05-31

Multifunctional carbon aerogels that are both highly compressible and conductive have broad potential applications in the range of sound insulator, sensor, oil absorption, and electronics. However, the preparation of such carbon aerogels has been proven to be very challenging. Here, we report fabrication of pressure-sensitive and conductive (PSC) carbon aerogels by pyrolysis of cellulose aerogels composed of poplars catkin (PC) microfibers with a tubular structure. The wet PC gels can be dried directly in an oven without any deformation, in marked contrast to the brittle nature of traditional carbon aerogels. The resultant PSC aerogels exhibit ultralow density (4.3 mg cm -3 ), high compressibility (80%), high electrical conductivity (0.47 S cm -1 ), and high absorbency (80-161 g g -1 ) for oils and organic liquids. The PSC aerogels have potential applications in various fields such as elastomeric conductors, absorption of oils from water and oil/water separation, as the PSC aerogels feature simple preparation process with low-cost biomass as the precursor.

Solute-Solvent Charge-Transfer Excitations and Optical Absorption of Hydrated Hydroxide from Time-Dependent Density-Functional Theory.

PubMed

Opalka, Daniel; Sprik, Michiel

2014-06-10

The electronic structure of simple hydrated ions represents one of the most challenging problems in electronic-structure theory. Spectroscopic experiments identified the lowest excited state of the solvated hydroxide as a charge-transfer-to-solvent (CTTS) state. In the present work we report computations of the absorption spectrum of the solvated hydroxide ion, treating both solvent and solute strictly at the same level of theory. The average absorption spectrum up to 25 eV has been computed for samples taken from periodic ab initio molecular dynamics simulations. The experimentally observed CTTS state near the onset of the absorption threshold has been analyzed at the generalized-gradient approximation (GGA) and with a hybrid density-functional. Based on results for the lowest excitation energies computed with the HSE hybrid functional and a Davidson diagonalization scheme, the CTTS transition has been found 0.6 eV below the first absorption band of liquid water. The transfer of an electron to the solvent can be assigned to an excitation from the solute 2pπ orbitals, which are subject to a small energetic splitting due to the asymmetric solvent environment, to the significantly delocalized lowest unoccupied orbital of the solvent. The distribution of the centers of the excited state shows that CTTS along the OH(-) axis of the hydroxide ion is avoided. Furthermore, our simulations indicate that the systematic error arising in the calculated spectrum at the GGA originates from a poor description of the valence band energies in the solution.

Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

NASA Astrophysics Data System (ADS)

Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

2016-02-01

A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

Ab initio calculation of the electronic absorption spectrum of liquid water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martiniano, Hugo F. M. C.; Galamba, Nuno; Cabral, Benedito J. Costa, E-mail: ben@cii.fc.ul.pt

2014-04-28

The electronic absorption spectrum of liquid water was investigated by coupling a one-body energy decomposition scheme to configurations generated by classical and Born-Oppenheimer Molecular Dynamics (BOMD). A Frenkel exciton Hamiltonian formalism was adopted and the excitation energies in the liquid phase were calculated with the equation of motion coupled cluster with single and double excitations method. Molecular dynamics configurations were generated by different approaches. Classical MD were carried out with the TIP4P-Ew and AMOEBA force fields. The BLYP and BLYP-D3 exchange-correlation functionals were used in BOMD. Theoretical and experimental results for the electronic absorption spectrum of liquid water are inmore » good agreement. Emphasis is placed on the relationship between the structure of liquid water predicted by the different models and the electronic absorption spectrum. The theoretical gas to liquid phase blue-shift of the peak positions of the electronic absorption spectrum is in good agreement with experiment. The overall shift is determined by a competition between the O–H stretching of the water monomer in liquid water that leads to a red-shift and polarization effects that induce a blue-shift. The results illustrate the importance of coupling many-body energy decomposition schemes to molecular dynamics configurations to carry out ab initio calculations of the electronic properties in liquid phase.« less

Ab initio calculation of the electronic absorption spectrum of liquid water

NASA Astrophysics Data System (ADS)

Martiniano, Hugo F. M. C.; Galamba, Nuno; Cabral, Benedito J. Costa

2014-04-01

The electronic absorption spectrum of liquid water was investigated by coupling a one-body energy decomposition scheme to configurations generated by classical and Born-Oppenheimer Molecular Dynamics (BOMD). A Frenkel exciton Hamiltonian formalism was adopted and the excitation energies in the liquid phase were calculated with the equation of motion coupled cluster with single and double excitations method. Molecular dynamics configurations were generated by different approaches. Classical MD were carried out with the TIP4P-Ew and AMOEBA force fields. The BLYP and BLYP-D3 exchange-correlation functionals were used in BOMD. Theoretical and experimental results for the electronic absorption spectrum of liquid water are in good agreement. Emphasis is placed on the relationship between the structure of liquid water predicted by the different models and the electronic absorption spectrum. The theoretical gas to liquid phase blue-shift of the peak positions of the electronic absorption spectrum is in good agreement with experiment. The overall shift is determined by a competition between the O-H stretching of the water monomer in liquid water that leads to a red-shift and polarization effects that induce a blue-shift. The results illustrate the importance of coupling many-body energy decomposition schemes to molecular dynamics configurations to carry out ab initio calculations of the electronic properties in liquid phase.

Water and solute absorption from carbohydrate-electrolyte solutions in the human proximal small intestine: a review and statistical analysis.

PubMed

Shi, Xiaocai; Passe, Dennis H

2010-10-01

The purpose of this study is to summarize water, carbohydrate (CHO), and electrolyte absorption from carbohydrate-electrolyte (CHO-E) solutions based on all of the triple-lumen-perfusion studies in humans since the early 1960s. The current statistical analysis included 30 reports from which were obtained information on water absorption, CHO absorption, total solute absorption, CHO concentration, CHO type, osmolality, sodium concentration, and sodium absorption in the different gut segments during exercise and at rest. Mean differences were assessed using independent-samples t tests. Exploratory multiple-regression analyses were conducted to create prediction models for intestinal water absorption. The factors influencing water and solute absorption are carefully evaluated and extensively discussed. The authors suggest that in the human proximal small intestine, water absorption is related to both total solute and CHO absorption; osmolality exerts various impacts on water absorption in the different segments; the multiple types of CHO in the ingested CHO-E solutions play a critical role in stimulating CHO, sodium, total solute, and water absorption; CHO concentration is negatively related to water absorption; and exercise may result in greater water absorption than rest. A potential regression model for predicting water absorption is also proposed for future research and practical application. In conclusion, water absorption in the human small intestine is influenced by osmolality, solute absorption, and the anatomical structures of gut segments. Multiple types of CHO in a CHO-E solution facilitate water absorption by stimulating CHO and solute absorption and lowering osmolality in the intestinal lumen.

[Study of high temperature water vapor concentration measurement method based on absorption spectroscopy].

PubMed

Chen, Jiu-ying; Liu, Jian-guo; He, Jun-feng; He, Ya-bai; Zhang, Guang-le; Xu, Zhen-yu; Gang, Qiang; Wang, Liao; Yao, Lu; Yuan, Song; Ruan, Jun; Dai, Yun-hai; Kan, Rui-feng

2014-12-01

Tunable diode laser absorption spectroscopy (TDLAS) has been developed to realize the real-time and dynamic measurement of the combustion temperature, gas component concentration, velocity and other flow parameters, owing to its high sensitivity, fast time response, non-invasive character and robust nature. In order to obtain accurate water vapor concentration at high temperature, several absorption spectra of water vapor near 1.39 μm from 773 to 1273 K under ordinary pressure were recorded in a high temperature experiment setup using a narrow band diode laser. The absorbance of high temperature absorption spectra was calculated by combined multi-line nonlinear least squares fitting method. Two water vapor absorption lines near 7154.35 and 7157.73 cm(-1) were selected for measurement of water vapor at high temperature. A model method for high temperature water vapor concentration was first proposed. Water vapor concentration from the model method at high temperature is in accordance with theoretical reasoning, concentration measurement standard error is less than 0.2%, and the relative error is less than 6%. The feasibility of this measuring method is verified by experiment.

Estimation of water absorption coefficient using the TDR method

NASA Astrophysics Data System (ADS)

Suchorab, Zbigniew; Majerek, Dariusz; Brzyski, Przemysław; Sobczuk, Henryk; Raczkowski, Andrzej

2017-07-01

Moisture accumulation and transport in the building barriers is an important feature that influences building performance, causing serious exploitation problems as increased energy use, mold and bacteria growth, decrease of indoor air parameters that may lead to sick building syndrome (SBS). One of the parameters that is used to describe moisture characteristic of the material is water absorption coefficient being the measure of capillary behavior of the material as a function of time and the surface area of the specimen. As usual it is determined using gravimetric methods according to EN 1925:1999 standard. In this article we demonstrate the possibility of determination of water absorption coefficient of autoclaved aerated concrete (AAC) using the Time Domain Reflectometry (TDR) method. TDR is an electric technique that had been adopted from soil science and can be successfully used for real-time monitoring of moisture transport in building materials and envelopes. Data achieved using TDR readouts show high correlation with standard method of moisture absorptivity coefficient determination.

Water-absorption rate equation of rice for brewing sake.

PubMed

Mizuma, Tomochika; Tomita, Akiko; Kitaoka, Atsushi; Kiyokawa, Yoshifumi; Wakai, Yoshinori

2007-01-01

This study was undertaken to analyze the kinetics of water absorption and to derive an equation for the rate at which water is absorbed by rice for brewing sake. We used two rice varieties: Gin-oumi, commonly used as a staple food, and Gohyakumangoku, a variety used particularly for brewing sake. The water-absorption rate equations of Gin-oumi and Gohyakumangoku were postulated based on the following equations. For Gin-oumi (water content, 11.5%), dx/dtheta=k(1-x)(n), n=1, k=(2 x 10(-9))exp(0.0604 x (t+273.15)). For Gohyakumangoku (11.5%), dx/dtheta=k(1-x)(n)(x+a), n=1, a=0.29, k=(2 x 10(-8))exp(0.0534 x (t+273.15)). Here, x, theta (min), and t ( degrees C) are the water absorbing ratio, time, and temperature, respectively. The result shows that the values of the temperature-dependence parameter k (min(-1)), as well as its curves, are different; a typical rice grain has a monotonically smooth curve, whereas that suitable for sake brewing has an S-shaped curve.

The THz Spectrum of Density Fluctuations of Water: The Viscoelastic Regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cunsolo, Alessandro

2015-01-01

Relevant advances in the knowledge of the water dynamics at mesoscopic scales are reviewed, while mainly focusing on the contribution provided by high resolution inelastic X-ray scattering (IXS). In particular it is discussed how the use of IXS has improved our understanding of viscoelastic properties of water at THz frequencies. This specifically involves some solid-like features such as the onset of shear wave propagation, a sound velocity surprisingly similar to the one of ice, and an anomalously low sound absorption coefficient. All these properties can be explained by assuming the coupling of THz density fluctuations with a structural relaxation processmore » connected to the breaking and forming of hydrogen bonds (HBs). This review also includes more recent IXS results demonstrating that, upon approaching supercritical conditions, relaxation phenomena in water gradually lose their structural character becoming essentially collisional in character. Furthermore, GHz spectroscopy results on supercooled water, suggesting the occurrence of a structural arrest, are discussed. An overview of the new opportunities offered by next generation IXS spectrometers finally concludes this review.« less

Contact sponge water absorption test implemented for in situ measures

NASA Astrophysics Data System (ADS)

Gaggero, Laura; Scrivano, Simona

2016-04-01

The contact sponge method is a non-destructive in-situ methodology used to estimate a water uptake coefficient. The procedure, unlike other in-situ measurement was proven to be directly comparable to the water uptake laboratory measurements, and was registered as UNI 11432:2011. The UNI Normal procedure requires to use a sponge with known density, soaked in water, weighed, placed on the material for 1 minute (UNI 11432, 2011; Pardini & Tiano, 2004), then weighed again. Difficulties arise in operating on test samples or on materials with porosity varied for decay. While carrying on the test, fluctuations in the bearing of the environmental parameters were negligible, but not the pressure applied to the surface, that induced the release of different water amounts towards the material. For this reason we designed a metal piece of the same diameter of the plate carrying the sponge, to be screwed at the tip of a pocket penetrometer. With this instrument the sponge was kept in contact with the surface for 1 minute applying two different loads, at first pushed with 0.3 kg/cm2 in order to press the sponge, but not its holder, against the surface. Then, a load of 1.1 kg/ cm2 was applied, still avoiding deviating the load to the sponge holder. We applied both the current and our implemented method to determine the water absorption by contact sponge on 5 fresh rock types (4 limestones: Fine - and Coarse grained Pietra di Vicenza, Rosso Verona, Breccia Aurora, and the silicoclastic Macigno sandstone). The results show that 1) the current methodology imply manual skill and experience to produce a coherent set of data; the variable involved are in fact not only the imposed pressure but also the compression mechanics. 2) The control on the applied pressure allowed reproducible measurements. Moreover, 3) the use of a thicker sponge enabled to apply the method even on rougher surfaces, as the device holding the sponge is not in contact with the tested object. Finally, 4) the

Special Features of Light Absorption by the Dimer of Bilayer Microparticles

NASA Astrophysics Data System (ADS)

Geints, Yu. É.; Panina, E. K.; Zemlyanov, A. A.

2018-05-01

Results of numerical simulation of light absorption by the dimer of bilayer spherical particles consisting of a water core and a polymer shell absorbing radiation are presented. The spatial distribution and the amplitude characteristics of the volume density of the absorbed power are investigated. It is shown that for a certain spatial dimer configuration, the maximal achievable density of the absorbed power is realized. It is also established that for closely spaced microcapsules with high shell absorption indices, the total power absorbed in the dimer volume can increase in comparison with the radiation absorption by two insulated microparticles.

Compressive strength and initial water absorption rate for cement brick containing high-density polyethylene (HDPE) as a substitutional material for sand

NASA Astrophysics Data System (ADS)

Ali, Noorwirdawati; Din, Norhasmiza; Sheikh Khalid, Faisal; Shahidan, Shahiron; Radziah Abdullah, Siti; Samad, Abdul Aziz Abdul; Mohamad, Noridah

2017-11-01

The rapid growth of today’s construction sector requires high amount of building materials. Bricks, known to have solid properties and easy to handle, which leads to the variety of materials added or replaced in its mixture. In this study, high density polyethylene (HDPE) was selected as the substitute materials in the making of bricks. The reason behind the use of HDPE is because of its recyclable properties and the recycling process that do not emit hazardous gases to the atmosphere. Other than that, the use of HDPE will help reducing the source of pollution by avoiding the millions of accumulated plastic waste in the disposal sites. Furthermore, the material has high endurance level and is weatherproof. This study was carried out on experimenting the substitute materials in the mixture of cement bricks, a component of building materials which is normally manufactured using the mixture of cement, sand and water, following a certain ratios, and left dried to produce blocks of bricks. A series of three different percentages of HDPE were used, which were 2.5%, 3.0% and 3.5%. Tests were done on the bricks, to study its compressive strength and the initial water absorption rate. Both tests were conducted on the seventh and 28th day. Based on the results acquired, for compressive strength tests on the 28th day, the use of 2.5% of HDPE shown values of 12.6 N/mm2 while the use of 3.0% of HDPE shown values of 12.5 N/mm2. Onto the next percentage, 3.5% of HDPE shown values of 12.5 N/mm2.

Effects of High Hydrostatic Pressure on Water Absorption of Adzuki Beans

PubMed Central

Ueno, Shigeaki; Shigematsu, Toru; Karo, Mineko; Hayashi, Mayumi; Fujii, Tomoyuki

2015-01-01

The effect of high hydrostatic pressure (HHP) treatment on dried soybean, adzuki bean, and kintoki kidney bean, which are low-moisture-content cellular biological materials, was investigated from the viewpoint of water absorption. The samples were vacuum-packed with distilled water and pressurized at 200 MPa and 25 °C for 10 min. After the HHP treatment, time courses of the moisture contents of the samples were measured, and the dimensionless moisture contents were estimated. Water absorption in the case of soybean could be fitted well by a simple water diffusion model. High pressures were found to have negligible effects on water absorption into the cotyledon of soybean and kintoki kidney bean. A non-linear least square method based on the Weibull equation was applied for the adzuki beans, and the effective water diffusion coefficient was found to increase significantly from 8.6 × 10−13 to 6.7 × 10−10 m2/s after HHP treatment. Approximately 30% of the testa of the adzuki bean was damaged upon HHP treatment, which was comparable to the surface area of the testa in the partially peeled adzuki bean sample. Thus, HHP was confirmed to promote mass transfer to the cotyledon of legumes with a tight testa. PMID:28231195

Monitoring Telluric Water Absorption with CAMAL

NASA Astrophysics Data System (ADS)

Baker, Ashley; Blake, Cullen; Sliski, David

2017-01-01

Ground-based observations are severely limited by telluric water vapor absorption features, which are highly variable in time and significantly complicate both spectroscopy and photometry in the near-infrared (NIR). To achieve the stability required to study Earth-sized exoplanets, monitoring the precipitable water vapor (PWV) becomes necessary to mitigate the impact of telluric lines on radial velocity measurements and transit light curves. To address this issue, we present the Camera for the Automatic Monitoring of Atmospheric Lines (CAMAL), a stand-alone, inexpensive 6-inch aperture telescope dedicated to measuring PWV at the Whipple Observatory. CAMAL utilizes three NIR narrowband filters to trace the amount of atmospheric water vapor affecting simultaneous observations with the MINiature Exoplanet Radial Velocity Array (MINERVA) and MINERVA-Red telescopes. We present the current design of CAMAL, discuss our calibration methods, and show PWV measurements taken with CAMAL compared to those of a nearby GPS water vapor monitor.

Temporal Variations of Telluric Water Vapor Absorption at Apache Point Observatory

NASA Astrophysics Data System (ADS)

Li, Dan; Blake, Cullen H.; Nidever, David; Halverson, Samuel P.

2018-01-01

Time-variable absorption by water vapor in Earth’s atmosphere presents an important source of systematic error for a wide range of ground-based astronomical measurements, particularly at near-infrared wavelengths. We present results from the first study on the temporal and spatial variability of water vapor absorption at Apache Point Observatory (APO). We analyze ∼400,000 high-resolution, near-infrared (H-band) spectra of hot stars collected as calibration data for the APO Galactic Evolution Experiment (APOGEE) survey. We fit for the optical depths of telluric water vapor absorption features in APOGEE spectra and convert these optical depths to Precipitable Water Vapor (PWV) using contemporaneous data from a GPS-based PWV monitoring station at APO. Based on simultaneous measurements obtained over a 3° field of view, we estimate that our PWV measurement precision is ±0.11 mm. We explore the statistics of PWV variations over a range of timescales from less than an hour to days. We find that the amplitude of PWV variations within an hour is less than 1 mm for most (96.5%) APOGEE field visits. By considering APOGEE observations that are close in time but separated by large distances on the sky, we find that PWV is homogeneous across the sky at a given epoch, with 90% of measurements taken up to 70° apart within 1.5 hr having ΔPWV < 1.0 mm. Our results can be used to help simulate the impact of water vapor absorption on upcoming surveys at continental observing sites like APO, and also to help plan for simultaneous water vapor metrology that may be carried out in support of upcoming photometric and spectroscopic surveys.

Electron Density Dropout Near Enceladus in the Context of Water-Vapor and Water-Ice

NASA Technical Reports Server (NTRS)

Farrell, W. M.; Kurth, W. S.; Gurnett, D. A.; Johnson, R. E.; Kaiser, M. L.; Wahlund, J.-E.; Waite, J. H., Jr.

2009-01-01

On 12 March 2008, the Cassini spacecraft made a close encounter with the Saturnian moon Enceladus, passing within 52 km of the moon. The spacecraft trajectory was intentionally-oriented in a southerly direction to create a close alignment with the intense water-dominated plumes emitted from the south polar region. During the passage, the Cassini Radio and Plasma Wave System (RPWS) detected two distinct radio signatures: 1) Impulses associated with small water-ice dust grain impacts and 2) an upper hybrid (UH) resonance emission that both intensified and displayed a sharp frequency decrease in the near-vicinity of the moon. The frequency decrease of the UH emission is associated with an unexpectedly sharp decrease in electron density from approximately 90 el/cubic cm to below 20 el/cubic cm that occurs on a time scale of a minute near the closest encounter with the moon. In this work, we consider a number of scenarios to explain this sharp electron dropout, but surmise that electron absorption by ice grains is the most likely process.

The river absorption capacity determination as a tool to evaluate state of surface water

NASA Astrophysics Data System (ADS)

Wilk, Paweł; Orlińska-Woźniak, Paulina; Gębala, Joanna

2018-02-01

In order to complete a thorough and systematic assessment of water quality, it is useful to measure the absorption capacity of a river. Absorption capacity is understood as a pollution load introduced into river water that will not cause permanent and irreversible changes in the aquatic ecosystem and will not cause a change in the classification of water quality in the river profile. In order to implement the method, the Macromodel DNS/SWAT basin for the Middle Warta pilot (central Poland) was used to simulate nutrient loads. This enabled detailed analysis of water quality in each water body and the assessment of the size of the absorption capacity parameter, which allows the determination of how much pollution can be added to the river without compromising its quality class. Positive values of the calculated absorption capacity parameter mean that it is assumed that the ecosystem is adjusted in such a way that it can eliminate pollution loads through a number of self-purification processes. Negative values indicate that the load limit has been exceeded, and too much pollution has been introduced into the ecosystem for it to be able to deal with through the processes of self-purification. Absorption capacity thus enables the connection of environmental standards of water quality and water quality management plans in order to meet these standards.

Density functional theory meta-GGA + U study of water incorporation in the metal-organic framework material Cu-BTC.

PubMed

Cockayne, Eric; Nelson, Eric B

2015-07-14

Water absorption in the metal-organic framework (MOF) material Cu-BTC, up to a concentration of 3.5 H2O per Cu ion, is studied via density functional theory at the meta-GGA + U level. The stable arrangements of water molecules show chains of hydrogen-bonded water molecules and a tendency to form closed cages at high concentration. Water clusters are stabilized primarily by a combination of water-water hydrogen bonding and Cu-water oxygen interactions. Stability is further enhanced by van der Waals interactions, electric field enhancement of water-water bonding, and hydrogen bonding of water to framework oxygens. We hypothesize that the tendency to form such stable clusters explains the particularly strong affinity of water to Cu-BTC and related MOFs with exposed metal sites.

Water absorption, retention and the swelling characteristics of cassava starch grafted with polyacrylic acid.

PubMed

Witono, J R; Noordergraaf, I W; Heeres, H J; Janssen, L P B M

2014-03-15

An important application of starch grafted with copolymers from unsaturated organic acids is the use as water absorbent. Although much research has been published in recent years, the kinetics of water absorption and the swelling behavior of starch based superabsorbents are relatively unexplored. Also, water retention under mechanical strain is usually not reported. Cassava starch was used since it has considerable economic potential in Asia. The gelatinized starch was grafted with acrylic acid and Fenton's initiator and crosslinked with N,N'-methylenebisacrylamide (MBAM). Besides a good initial absorption capacity, the product could retain up to 63 g H2O/g under severe suction. The material thus combines a good absorption capacity with sufficient gel strength. The mathematical analysis of the absorption kinetics shows that at conditions of practical interest, the rate of water penetration into the gel is determined by polymer chain relaxations and not by osmotic driven diffusion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Improvement of scattering correction for in situ coastal and inland water absorption measurement using exponential fitting approach

NASA Astrophysics Data System (ADS)

Ye, Huping; Li, Junsheng; Zhu, Jianhua; Shen, Qian; Li, Tongji; Zhang, Fangfang; Yue, Huanyin; Zhang, Bing; Liao, Xiaohan

2017-10-01

The absorption coefficient of water is an important bio-optical parameter for water optics and water color remote sensing. However, scattering correction is essential to obtain accurate absorption coefficient values in situ using the nine-wavelength absorption and attenuation meter AC9. Establishing the correction always fails in Case 2 water when the correction assumes zero absorption in the near-infrared (NIR) region and underestimates the absorption coefficient in the red region, which affect processes such as semi-analytical remote sensing inversion. In this study, the scattering contribution was evaluated by an exponential fitting approach using AC9 measurements at seven wavelengths (412, 440, 488, 510, 532, 555, and 715 nm) and by applying scattering correction. The correction was applied to representative in situ data of moderately turbid coastal water, highly turbid coastal water, eutrophic inland water, and turbid inland water. The results suggest that the absorption levels in the red and NIR regions are significantly higher than those obtained using standard scattering error correction procedures. Knowledge of the deviation between this method and the commonly used scattering correction methods will facilitate the evaluation of the effect on satellite remote sensing of water constituents and general optical research using different scattering-correction methods.

Near-infrared studies of glucose and sucrose in aqueous solutions: water displacement effect and red shift in water absorption from water-solute interaction.

PubMed

Jung, Youngeui; Hwang, Jungseek

2013-02-01

We used near infrared spectroscopy to obtain concentration dependent glucose absorption spectra in aqueous solutions in the near-infrared range (3800-7500 cm(-1)). Here we introduce a new method to obtain reliable glucose absorption bands from aqueous glucose solutions without measuring the water displacement coefficients of glucose separately. Additionally, we were able to extract the water displacement coefficients of glucose, and this may offer a new general method using spectroscopy techniques applicable to other water-soluble materials. We also observed red shifts in the absorption bands of water in the hydration shell around solute molecules, which comes from the contribution of the interacting water molecules around the glucose molecules in solutions. The intensity of the red shift gets larger as the concentration increases, which indicates that as the concentration increases more water molecules are involved in the interaction. However, the red shift in frequency does not seem to depend significantly on the concentration. We also performed the same measurements and analysis with sucrose instead of glucose as solute and compared.

Studies of Water Absorption Behavior of Plant Fibers at Different Temperatures

NASA Astrophysics Data System (ADS)

Saikia, Dip

2010-05-01

Moisture absorption of natural fiber plastic composites is one major concern in their outdoor applications. The absorbed moisture has many detrimental effects on the mechanical performance of these composites. A knowledge of the moisture diffusivity, permeability, and solubility is very much essential for the application of natural fibers as an excellent reinforcement in polymers. An effort has been made to study the water absorption behavior of some natural fibers such as bowstring hemp, okra, and betel nut at different temperatures to improve the long-term performance of composites reinforced with these fibers. The gain in moisture content in the fibers due to water absorption was measured as a function of exposure time at temperatures ranging from 300 K to 340 K. The thermodynamic parameters of the sorption process, such as diffusion coefficients and corresponding activation energies, were estimated.

Site of water vapor absorption in the desert cockroach, Arenivaga investigata.

PubMed Central

O'Donnell, M J

1977-01-01

The desert cockroach, Arenivaga investigata, can gain weight by absorption of water-vapor from unsaturated atmospheres above 82.5% relative humidity. Blocking the anus or the dorsal surface with wax does not prevent water vapor uptake, but interference with movements of the mouthparts or blocking the mouth with wax-prevents such uptake. Weight gains are associated with the protrusion from the mouth of two bladder-like extensions of the hypopharynx. During absorption these structures are warmer than the surrounding mouthparts, their surface temperature increasing with relative humidity. This suggests that the surfaces of the bladder-like structures function at least as sites for condensation of water vapor, but the precise location of its transfer into the hemolymph has not yet been identified. Images PMID:266217

Microwave measurements of the absolute values of absorption by water vapour in the atmosphere.

PubMed

Hogg, D C; Guiraud, F O

1979-05-31

MEASUREMENT of the absolute value of absorption by water vapour at microwave frequencies is difficult because the effect is so small. Far in the wings of the absorption lines, in the so-called 'windows' of the spectrum, it is especially difficult to achieve high accuracy in the free atmosphere. But it is in these windows that the behaviour of the absorption is important from both applied and scientific points of view. Satellite communications, remote sensing of the atmosphere, and radioastronomy, are all influenced by this behaviour. Measurements on an Earth-space path are reported here; the results indicate a nonlinear relationship between absorption and water-vapour content.

European Regional Climate Zone Modeling of a Commercial Absorption Heat Pump Hot Water Heater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Vishaldeep; Shen, Bo; Keinath, Chris

2017-01-01

High efficiency gas-burning hot water heating takes advantage of a condensing heat exchanger to deliver improved combustion efficiency over a standard non-condensing configuration. The water heating is always lower than the gas heating value. In contrast, Gas Absorption Heat Pump (GAHP) hot water heating combines the efficiency of gas burning with the performance increase from a heat pump to offer significant gas energy savings. An ammonia-water system also has the advantage of zero Ozone Depletion Potential and low Global Warming Potential. In comparison with air source electric heat pumps, the absorption system can maintain higher coefficients of performance in coldermore » climates. In this work, a GAHP commercial water heating system was compared to a condensing gas storage system for a range of locations and climate zones across Europe. The thermodynamic performance map of a single effect ammonia-water absorption system was used in a building energy modeling software that could also incorporate the changing ambient air temperature and water mains temperature for a specific location, as well as a full-service restaurant water draw pattern.« less

Water absorption tests for measuring permeability of field concrete.

DOT National Transportation Integrated Search

2013-09-01

The research results from CFIRE Project 04-06 were communicated to engineers and researchers in this project. : Specifically, the water absorption of concrete samples (i.e., 2-in. thick, 4-in. diameter discs cut from concrete : cylinders) was found s...

Kids in Space Water Absorption Flight Procedures #40 Demo

NASA Image and Video Library

2010-09-15

ISS024-E-014988 (15 Sept. 2010) --- NASA astronaut Tracy Caldwell Dyson, Expedition 24 flight engineer, conducts a demonstration for the "Kids in Space" session for Water Absorption Flight Procedures #40 in the Columbus laboratory of the International Space Station.

Kids in Space Water Absorption Flight Procedures 40 Demo

NASA Image and Video Library

2010-09-15

ISS024-E-014993 (15 Sept. 2010) --- NASA astronaut Tracy Caldwell Dyson, Expedition 24 flight engineer, conducts a demonstration for the "Kids in Space" session for Water Absorption Flight Procedures #40 in the Columbus laboratory of the International Space Station.

The Density Matrix for Single-mode Light after k-Photon Absorption

NASA Astrophysics Data System (ADS)

Voigt, H.; Bandilla, A.

In order to continue and generalize the studies of the density matrix of a light field undergoing k-photon absorption, in this paper we put the emphasis on the off-diagonal elements. The solution obtained earlier for the diagonal elements describing the photon statistics can be found as a special case but will not be discussed again. The general solution calculated by recursion shows an asymptotic behaviour if the initial photon number is sufficiently high. Only the initial phase information survives. Illustrating the solution we start with coherent light and a generalized coherent state.Translated AbstractDie Dichtematrix eines Lichtstrahls nach k-Photonen-Absorption aus einer ModeWir führen die Betrachtungen über das Verhalten der Dichtematrix eines Lichtfeldes nach k-Photonen-Absorption aus einer Mode verallgemeinernd weiter und konzentrieren uns auf die Nichtdiagonalelemente. Die im folgenden angegebene allgemeine Lösung, die durch Rekursion gefunden wurde, enthält die schon früher erhaltene, jedoch hier nicht weiter diskutierte Lösung für die Diagonalelemente als Spezialfall. Sie zeigt ferner, daß es einen asymptotischen Zustand gibt, der eine von der Ausgangsintensität unabhängige Information über die Ausgangsphase enthält. Zur Diskussion der Lösung werden verschiedene Anfangsbedingungen betrachtet, so z. B. kohärentes Licht und kohärentes Licht, das ein Medium mit nichtlinearem Brechungsindex durchlaufen hat (Kerr-Effekt).

Potential bias in TEOS10 density of sea water samples

NASA Astrophysics Data System (ADS)

Budéus, G. Th.

2018-04-01

Direct density measurements of ocean water samples are compared to TEOS10 derived densities. The water sample set includes waters from remote areas as Antarctic waters and the central Arctic, but also waters of regions that resemble closely the reference composition of TEOS10. With few exceptions, the measured densities are smaller than those derived according to TEOS10. The result suggests a potential systematic overestimation of density by TEOS10. For the majority of waters the deviations are about 10 g/m3.

Ion-water wires in imidazolium-based ionic liquid/water solutions induce unique trends in density.

PubMed

Ghoshdastidar, Debostuti; Senapati, Sanjib

2016-03-28

Ionic liquid/water binary mixtures are rapidly gaining popularity as solvents for dissolution of cellulose, nucleobases, and other poorly water-soluble biomolecules. Hence, several studies have focused on measuring the thermophysical properties of these versatile mixtures. Among these, 1-ethyl-3-methylimidazolium ([emim]) cation-based ILs containing different anions exhibit unique density behaviours upon addition of water. While [emim][acetate]/water binary mixtures display an unusual rise in density with the addition of low-to-moderate amounts of water, those containing the [trifluoroacetate] ([Tfa]) anion display a sluggish decrease in density. The density of [emim][tetrafluoroborate] ([emim][BF4])/water mixtures, on the other hand, declines rapidly in close accordance with the experimental reports. Here, we unravel the structural basis underlying this unique density behavior of [emim]-based IL/water mixtures using all-atom molecular dynamics (MD) simulations. The results revealed that the distinct nature of anion-water hydrogen bonded networks in the three systems was a key in modulating the observed unique density behaviour. Vast expanses of uninterrupted anion-water-anion H-bonded stretches, denoted here as anion-water wires, induced significant structuring in [emim][Ac]/water mixtures that resulted in the density rise. Conversely, the presence of intermittent large water clusters disintegrated the anion-water wires in [emim][Tfa]/water and [emim][BF4]/water mixtures to cause a monotonic density decrease. The differential nanostructuring affected the dynamics of the solutions proportionately, with the H-bond making and breaking dynamics found to be greatly retarded in [emim][Ac]/water mixtures, while it exhibited a faster relaxation in the other two binary solutions.

Dataset used to improve liquid water absorption models in the microwave

DOE Data Explorer

Turner, David

2015-12-14

Two datasets, one a compilation of laboratory data and one a compilation from three field sites, are provided here. These datasets provide measurements of the real and imaginary refractive indices and absorption as a function of cloud temperature. These datasets were used in the development of the new liquid water absorption model that was published in Turner et al. 2015.

Evidence for direct water absorption by shallow-rooted desert plants in desert-oasis ecotone, Northwest China

NASA Astrophysics Data System (ADS)

Fang, Jing

2014-05-01

Besides the absorption by roots from the soil substrate, it has long been known that plants exhibit alternative water-absorption strategies, particularly in drought-prone environments. For many tropical epiphytic orchids, air moisture can be absorbed directly by aerial roots. Some conifers are also found to utilize air moisture by foliar absorption during the summer fog season. However, few studies have been carried out on the atmospheric water vapor absorption by shallow-rooted desert plants. We conducted experiments in desert-oasis ecotone and investigated the effects of dew absorbed by three kinds of shallow-rooted seedlings on net photosynthesis rate, as well as on other water relations variables. Three kinds of typical shallow-rooted desert species (Bassia dasyphylla, Salsola collina and Corispermum declinatum) have been chosen and potted. Each species were subjected to contrasting watering regimes (normal and deficient) and different air moisture conditions (having dew and having no dew) for 10 weeks. Net photosynthesis rate was measured on six occasions during the study. Other water relations variables (midday shoot water potential, relative water content, stomatal conductance) were also measured. Under the dew conditions, average net photosynthesis rate, shoot water potential, leaf relative water content and stomatal conductance increased, with greater responses observed for plants subjected to a deficient watering regime than for well-watered plants. These results indicated dew occurred in arid region could be utilized through foliar absorption by some shallow-rooted plants, and for the shallow-rooted plants, the presence of dew could significantly relieve the deficit of water in water-stressed regime.

Physicochemical properties of macrogol ointment and emulsion ointment blend developed for regulation of water absorption.

PubMed

Noda, Yasuhiro; Watanabe, Kazuya; Sanagawa, Akimasa; Sobajima, Yu; Fujii, Satoshi

2011-10-31

Pressure ulcers can form with excess pressure and shearing stress on skin tissue. Because pressure ulcer is often accompanies by exudates, selection of appropriate topical emulsion ointment is difficult. Blended ointments consisting of emulsion base and water-soluble base are clinically used for adjustment of wound moist environment. Because regulating the amount of wound exudates can enhance treatment efficacy, two new blended ointments were developed. LY-SL blended ointment consisted of lysozyme hydrochloride water-in-oil (w/o) emulsion (LY-cream) and sulfadiazine macrogol (polyethylene glycol) ointment (SL-pasta). TR-SL blended ointment consisted of tretinoin tocoferil oil-in-water (o/w) emulsion (TR-cream) and SL-pasta (TR-SL). LY-SL and TR-SL were applied to Franz diffusion cell with cellulose membranes for the evaluation of water absorption characteristics at 32 °C. Water absorption rate constants (mg/cm(2)/min(0.5)) were 12.5, 16.3 and 34.6 for LY-cream, TR-cream and SL-pasta, respectively. Water absorption rate constants for LY-SL and TR-SL (SL-pasta 70%) exhibited intermediate values of 21.2 and 27.2, as compared to each ointment alone, respectively. Because amount of water absorbed was linearly related to square root of time, it was suggested that water-absorbable macrogol was surrounded by oily ingredients forming matrix structure. This diffusion-limited structure may regulate water absorption capacity. This is the first report of physicochemical properties of macrogol ointment and emulsion ointment blend developed for regulation of water absorption. The blended ointment can properly regulate amount of exudates in wounds and may be useful for treatment of pressure ulcers. Copyright © 2011 Elsevier B.V. All rights reserved.

Water absorption and biodegradation kinetics of highly filled EOC-FS biocomposites

NASA Astrophysics Data System (ADS)

Zykova, A. K.; Pantyukhov, P. V.; Platov, Yu. T.; Bobojonova, G. A.; Ramos, C. Chaverri; Popov, A. A.

2017-12-01

The paper analyzes the water absorption and biodegradation kinetics in highly filled biocomposites based on ethylene-octene copolymer (EOC) and oil flax straw (FS). It is shown that adding the filler to EOC increases the water absorption from 0 to 22%. The tendency can be explained both by the low interfacial adhesion of EOC to FS and by the hydrophilic nature of the filler. According to biodegradation tests (10 months), the mass of pure EOC remains unchanged, suggesting that it fails to biodegrade in the environment. Increasing the filler content increases the weight loss of the composites and the degree of microbiological contamination (fungi filaments, bacteria) as evidenced by optical microscopy.

Water vapour foreign-continuum absorption in near-infrared windows from laboratory measurements.

PubMed

Ptashnik, Igor V; McPheat, Robert A; Shine, Keith P; Smith, Kevin M; Williams, R Gary

2012-06-13

For a long time, it has been believed that atmospheric absorption of radiation within wavelength regions of relatively high infrared transmittance (so-called 'windows') was dominated by the water vapour self-continuum, that is, spectrally smooth absorption caused by H(2)O--H(2)O pair interaction. Absorption due to the foreign continuum (i.e. caused mostly by H(2)O--N(2) bimolecular absorption in the Earth's atmosphere) was considered to be negligible in the windows. We report new retrievals of the water vapour foreign continuum from high-resolution laboratory measurements at temperatures between 350 and 430 K in four near-infrared windows between 1.1 and 5 μm (9000-2000 cm(-1)). Our results indicate that the foreign continuum in these windows has a very weak temperature dependence and is typically between one and two orders of magnitude stronger than that given in representations of the continuum currently used in many climate and weather prediction models. This indicates that absorption owing to the foreign continuum may be comparable to the self-continuum under atmospheric conditions in the investigated windows. The calculated global-average clear-sky atmospheric absorption of solar radiation is increased by approximately 0.46 W m(-2) (or 0.6% of the total clear-sky absorption) by using these new measurements when compared with calculations applying the widely used MTCKD (Mlawer-Tobin-Clough-Kneizys-Davies) foreign-continuum model.

New analytical technique for carbon dioxide absorption solvents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pouryousefi, F.; Idem, R.O.

2008-02-15

The densities and refractive indices of two binary systems (water + MEA and water + MDEA) and three ternary systems (water + MEA + CO{sub 2}, water + MDEA + CO{sub 2}, and water + MEA + MDEA) used for carbon dioxide (CO{sub 2}) capture were measured over the range of compositions of the aqueous alkanolamine(s) used for CO{sub 2} absorption at temperatures from 295 to 338 K. Experimental densities were modeled empirically, while the experimental refractive indices were modeled using well-established models from the known values of their pure-component densities and refractive indices. The density and Gladstone-Dale refractive indexmore » models were then used to obtain the compositions of unknown samples of the binary and ternary systems by simultaneous solution of the density and refractive index equations. The results from this technique have been compared with HPLC (high-performance liquid chromatography) results, while a third independent technique (acid-base titration) was used to verify the results. The results show that the systems' compositions obtained from the simple and easy-to-use refractive index/density technique were very comparable to the expensive and laborious HPLC/titration techniques, suggesting that the refractive index/density technique can be used to replace existing methods for analysis of fresh or nondegraded, CO{sub 2}-loaded, single and mixed alkanolamine solutions.« less

Semi-analytical Model for Estimating Absorption Coefficients of Optically Active Constituents in Coastal Waters

NASA Astrophysics Data System (ADS)

Wang, D.; Cui, Y.

2015-12-01

The objectives of this paper are to validate the applicability of a multi-band quasi-analytical algorithm (QAA) in retrieval absorption coefficients of optically active constituents in turbid coastal waters, and to further improve the model using a proposed semi-analytical model (SAA). The ap(531) and ag(531) semi-analytically derived using SAA model are quite different from the retrievals procedures of QAA model that ap(531) and ag(531) are semi-analytically derived from the empirical retrievals results of a(531) and a(551). The two models are calibrated and evaluated against datasets taken from 19 independent cruises in West Florida Shelf in 1999-2003, provided by SeaBASS. The results indicate that the SAA model produces a superior performance to QAA model in absorption retrieval. Using of the SAA model in retrieving absorption coefficients of optically active constituents from West Florida Shelf decreases the random uncertainty of estimation by >23.05% from the QAA model. This study demonstrates the potential of the SAA model in absorption coefficients of optically active constituents estimating even in turbid coastal waters. Keywords: Remote sensing; Coastal Water; Absorption Coefficient; Semi-analytical Model

Optoacoustic measurements of water vapor absorption at selected CO laser wavelengths in the 5-micron region

NASA Technical Reports Server (NTRS)

Menzies, R. T.; Shumate, M. S.

1976-01-01

Measurements of water vapor absorption were taken with a resonant optoacoustical detector (cylindrical pyrex detector, two BaF2 windows fitted into end plates at slight tilt to suppress Fabry-Perot resonances), for lack of confidence in existing spectral tabular data for the 5-7 micron region, as line shapes in the wing regions of water vapor lines are difficult to characterize. The measurements are required for air pollution studies using a CO laser, to find the differential absorption at the wavelengths in question due to atmospheric constituents other than water vapor. The design and performance of the optoacoustical detector are presented. Effects of absorption by ambient NO are considered, and the fixed-frequency discretely tunable CO laser is found suitable for monitoring urban NO concentrations in a fairly dry climate, using the water vapor absorption data obtained in the study.

Theoretical Calculation and Validation of the Water Vapor Continuum Absorption

NASA Technical Reports Server (NTRS)

Ma, Qiancheng; Tipping, Richard H.

1998-01-01

The primary objective of this investigation is the development of an improved parameterization of the water vapor continuum absorption through the refinement and validation of our existing theoretical formalism. The chief advantage of our approach is the self-consistent, first principles, basis of the formalism which allows us to predict the frequency, temperature and pressure dependence of the continuum absorption as well as provide insights into the physical mechanisms responsible for the continuum absorption. Moreover, our approach is such that the calculated continuum absorption can be easily incorporated into satellite retrieval algorithms and climate models. Accurate determination of the water vapor continuum is essential for the next generation of retrieval algorithms which propose to use the combined constraints of multispectral measurements such as those under development for EOS data analysis (e.g., retrieval algorithms based on MODIS and AIRS measurements); current Pathfinder activities which seek to use the combined constraints of infrared and microwave (e.g., HIRS and MSU) measurements to improve temperature and water profile retrievals, and field campaigns which seek to reconcile spectrally-resolved and broad-band measurements such as those obtained as part of FIRE. Current widely used continuum treatments have been shown to produce spectrally dependent errors, with the magnitude of the error dependent on temperature and abundance which produces errors with a seasonal and latitude dependence. Translated into flux, current water vapor continuum parameterizations produce flux errors of order 10 W/sq m, which compared to the 4 W/sq m magnitude of the greenhouse gas forcing and the 1-2 W/sq m estimated aerosol forcing is certainly climatologically significant and unacceptably large. While it is possible to tune the empirical formalisms, the paucity of laboratory measurements, especially at temperatures of interest for atmospheric applications, preclude

Theoretical Calculation and Validation of the Water Vapor Continuum Absorption

NASA Technical Reports Server (NTRS)

Ma, Qiancheng; Tipping, Richard H.

1998-01-01

The primary objective of this investigation is the development of an improved parameterization of the water vapor continuum absorption through the refinement and validation of our existing theoretical formalism. The chief advantage of our approach is the self-consistent, first principles, basis of the formalism which allows us to predict the frequency, temperature and pressure dependence of the continuum absorption as well as provide insights into the physical mechanisms responsible for the continuum absorption. Moreover, our approach is such that the calculated continuum absorption can be easily incorporated into satellite retrieval algorithms and climate models. Accurate determination of the water vapor continuum is essential for the next generation of retrieval algorithms which propose to use the combined constraints of multi-spectral measurements such as those under development for EOS data analysis (e.g., retrieval algorithms based on MODIS and AIRS measurements); current Pathfinder activities which seek to use the combined constraints of infrared and microwave (e.g., HIRS and MSU) measurements to improve temperature and water profile retrievals, and field campaigns which seek to reconcile spectrally-resolved and broad-band measurements such as those obtained as part of FIRE. Current widely used continuum treatments have been shown to produce spectrally dependent errors, with the magnitude of the error dependent on temperature and abundance which produces errors with a seasonal and latitude dependence. Translated into flux, current water vapor continuum parameterizations produce flux errors of order 10 W/ml, which compared to the 4 W/m' magnitude of the greenhouse gas forcing and the 1-2 W/m' estimated aerosol forcing is certainly climatologically significant and unacceptably large. While it is possible to tune the empirical formalisms, the paucity of laboratory measurements, especially at temperatures of interest for atmospheric applications, preclude tuning

Spectral control of an alexandrite laser for an airborne water-vapor differential absorption lidar system

NASA Technical Reports Server (NTRS)

Ponsardin, Patrick; Grossmann, Benoist E.; Browell, Edward V.

1994-01-01

A narrow-linewidth pulsed alexandrite laser has been greatly modified for improved spectral stability in an aircraft environment, and its operation has been evaluated in the laboratory for making water-vapor differential absorption lidar measurements. An alignment technique is described to achieve the optimum free spectral range ratio for the two etalons inserted in the alexandrite laser cavity, and the sensitivity of this ratio is analyzed. This technique drastically decreases the occurrence of mode hopping, which is commonly observed in a tunable, two-intracavity-etalon laser system. High spectral purity (greater than 99.85%) at 730 nm is demonstrated by the use of a water-vapor absorption line as a notch filter. The effective cross sections of 760-nm oxygen and 730-nm water-vapor absorption lines are measured at different pressures by using this laser, which has a finite linewidth of 0.02 cm(exp -1) (FWHM). It is found that for water-vapor absorption linewidths greater than 0.04 cm(exp -1) (HWHM), or for altitudes below 10 km, the laser line can be considered monochromatic because the measured effective absorption cross section is within 1% of the calculated monochromatic cross section. An analysis of the environmental sensitivity of the two intracavity etalons is presented, and a closed-loop computer control for active stabilization of the two intracavity etalons in the alexandrite laser is described. Using a water-vapor absorption line as a wavelength reference, we measure a long-term frequency drift (approximately 1.5 h) of less than 0.7 pm in the laboratory.

Limiting Short-term Noise versus Optical Density in a Direct Absorption Spectrometer for Trace Gas Detection

NASA Astrophysics Data System (ADS)

Jervis, D.

2016-12-01

Field-deployable trace gas monitors are important for understanding a multitude of atmospheric processes: from forest photosynthesis and respiration [1], to fugitive methane emissions [2] and satellite measurement validation [3]. Consequently, a detailed knowledge of the performance limitations of these instruments is essential in order to establish reliable datasets. We present the short-term ( >1 Hz) performance of a long-pass direct absorption spectrometer as a function of the optical density of the absorption transition being probed. In particular, we identify fluctuations in the laser intensity as limiting the optical density uncertainty to 4x10-6/√Hz for weak transitions, and noise in the laser drive current as limiting the fractional noise in the optical density to 4x10-5/√Hz for deep transitions. We provide numerical and analytical predictions for both effects, as well as using the understanding of this phenomena to estimate how noise on neighboring strong and weak transitions couple to each other. All measurements were performed using the Aerodyne Research TILDAS Monitor, but are general to any instrument that uses direct absorption spectroscopy as a detection method. Wehr, R., et al. "Seasonality of temperate forest photosynthesis and daytime respiration." Nature 534.7609 (2016): 680-683. Conley, S., et al. "Methane emissions from the 2015 Aliso Canyon blowout in Los Angeles, CA." Science 351.6279 (2016): 1317-1320. Emmons, L. K., et al. "Validation of Measurements of Pollution in the Troposphere (MOPITT) CO retrievals with aircraft in situ profiles." Journal of Geophysical Research: Atmospheres 109.D3 (2004).

Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants.

PubMed

Shao, Jiahui; Fang, Xuliang; He, Yiliang; Jin, Qiang

2008-01-01

Abstract Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditional chlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaks in the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose. Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditions on the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration, liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9% was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically found to be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammonia removal rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plant membrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatment plant, also paved the way towards a larger scale application.

Airborne differential absorption lidar system for water vapor investigations

NASA Technical Reports Server (NTRS)

Browell, E. V.; Carter, A. F.; Wilkerson, T. D.

1981-01-01

Range-resolved water vapor measurements using the differential-absorption lidar (DIAL) technique is described in detail. The system uses two independently tunable optically pumped lasers operating in the near infrared with laser pulses of less than 100 microseconds separation, to minimize concentration errors caused by atmospheric scattering. Water vapor concentration profiles are calculated for each measurement by a minicomputer, in real time. The work is needed in the study of atmospheric motion and thermodynamics as well as in forestry and agriculture problems.

Microwave resonance lamp absorption technique for measuring temperature and OH number density in combustion environments

NASA Technical Reports Server (NTRS)

Lempert, Walter R.

1988-01-01

A simple technique for simultaneous determination of temperature and OH number density is described, along with characteristic results obtained from measurements using a premixed, hydrogen air flat flame burner. The instrumentation is based upon absorption of resonant radiation from a flowing microwave discharge lamp, and is rugged, relatively inexpensive, and very simple to operate.

Reduction of the capillary water absorption of foamed concrete by using the porous aggregate

NASA Astrophysics Data System (ADS)

Namsone, E.; Sahmenko, G.; Namsone, E.; Korjakins, A.

2017-10-01

The article reports on the research of reduction of the capillary water absorption of foamed concrete (FC) by using the porous aggregate such as the granules of expanded glass (EG) and the cenospheres (CS). The EG granular aggregate is produced by using recycled glass and blowing agents, melted down in high temperature. The unique structure of the EG granules is obtained where the air is kept closed inside the pellet. The use of the porous aggregate in the preparation process of the FC samples provides an opportunity to improve some physical and mechanical properties of the FC, classifying it as a product of high-performance. In this research the FC samples were produced by adding the EG granules and the CS. The capillary water absorption of hardened samples has been verified. The pore size distribution has been determined by microscope. It is a very important characteristic, specifically in the cold climate territories-where temperature often falls below zero degrees. It is necessary to prevent forming of the micro sized pores in the final structure of the material as it reduces its water absorption capacity. In addition, at a below zero temperature water inside these micro sized pores can increase them by expanding the stress on their walls during the freezing process. Research of the capillary water absorption kinetics can be practical for prevision of the FC durability.

High-density regular arrays of nanometer-scale rods formed on silicon surfaces via femtosecond laser irradiation in water.

PubMed

Shen, Mengyan; Carey, James E; Crouch, Catherine H; Kandyla, Maria; Stone, Howard A; Mazur, Eric

2008-07-01

We report on the formation of high-density regular arrays of nanometer-scale rods using femtosecond laser irradiation of a silicon surface immersed in water. The resulting surface exhibits both micrometer-scale and nanometer-scale structures. The micrometer-scale structure consists of spikes of 5-10 mum width, which are entirely covered by nanometer-scale rods that are roughly 50 nm wide and normal to the surface of the micrometer-scale spikes. The formation of the nanometer-scale rods involves several processes: refraction of laser light in highly excited silicon, interference of scattered and refracted light, rapid cooling in water, roughness-enhanced optical absorptance, and capillary instabilities.

Amount of leachant and water absorption levels of wood treated with borates and water repellents.

PubMed

Baysal, Ergun; Sonmez, Abdullah; Colak, Mehmet; Toker, Hilmi

2006-12-01

Wood protection efficacy of borates against biological agents, flame retardancy, and suitability to the environment is well known. Since borates can be applied to timber as water based solutions, they are preferred economically as well. Even though they are highly mobile in wood, boron compounds are widely used in timber preservation. Borates migrate in liquid and increase the hygroscopicity of wood in damp conditions. This study deals with the physical restriction of water access in wood by impregnating water repellent agents into wood to limit amount of leachant and water absorption levels of wood after boron treatment. Borates were incorporated with polyethylene glycol-400 (PEG-400) their bulking effect in wood was considered. Results indicated that the amount of leachates from wood treated with borates in PEG-400 was remarkably higher compared to those of wood treated with the aqueous solutions of borates. Water absorption (WA) levels of wood treated with aqueous solutions of borates were higher than those of their treated samples with the solutions in PEG-400. Secondary treatments of wood with the water repellent (WR) chemicals following borate impregnation reduced the leaching of chemicals from wood in water and also WA of the specimens were less than those of the wood treated with only borates from aqueous and PEG solutions. Styrene (St) was the most effective monomer among the other agents used in terms of immobility effect on borates and WA.

Moisture Absorption Behaviour of Biopolymer Polycapralactone (PCL) / Organo Modified Montmorillonite Clay (OMMT) biocomposite films

NASA Astrophysics Data System (ADS)

Malik, Neetu; Shrivastava, Sharad; Bandhu Ghosh, Subrata

2018-04-01

Bio composite materials were fabricated using mixing biodegradable polymer polycaptalactone (PCL) and Organo Modified Montmorillonite Clay (OMMT) through solution casting. Various samples of bio composite films were prepared by varying the OMMT wt% composition by 0.1%, 0.5%, 1% and 1.5%. Thereafter, the density and water absorption of the composites were investigated with respect to immersion time in water. The moisture absorption results show that with an increase in weight percentage (from 0.1 to wt 1.5%) of OMMT within the bio polymer films, the absorption value of bio-nanocomposite films reduced rapidly from 34.4% to 22.3%. The density of hybrid composites also increased with increase in weight percentage of OMMT. The swelling characteristic of PCL increased with increasing % of OMMT clay. These results indicate that the optimized composition of constituents in composite membrane could effectively reduce the anhydrous conditions of bio-composite film.

Acceptor and Excitation Density Dependence of the Ultrafast Polaron Absorption Signal in Donor-Acceptor Organic Solar Cell Blends.

PubMed

Zarrabi, Nasim; Burn, Paul L; Meredith, Paul; Shaw, Paul E

2016-07-21

Transient absorption spectroscopy on organic semiconductor blends for solar cells typically shows efficient charge generation within ∼100 fs, accounting for the majority of the charge carriers. In this Letter, we show using transient absorption spectroscopy on blends containing a broad range of acceptor content (0.01-50% by weight) that the rise of the polaron signal is dependent on the acceptor concentration. For low acceptor content (<10% by weight), the polaron signal rises gradually over ∼1 ps with most polarons generated after 200 fs, while for higher acceptor concentrations (>10%) most polarons are generated within 200 fs. The rise time in blends with low acceptor content was also found to be sensitive to the pump fluence, decreasing with increasing excitation density. These results indicate that the sub-100 fs rise of the polaron signal is a natural consequence of both the high acceptor concentrations in many donor-acceptor blends and the high excitation densities needed for transient absorption spectroscopy, which results in a short average distance between the exciton and the donor-acceptor interface.

New in situ Aerosol Spectral Optical Measurements over 300-700 nm, Extinction and Total Absorption, Paired with Absorption from Water- and Methanol-soluble Aerosol Extracts

NASA Astrophysics Data System (ADS)

Jordan, C. E.; Stauffer, R. M.; Lamb, B.; Novak, M. G.; Mannino, A.; Hudgins, C.; Thornhill, K. L., II; Crosbie, E.; Winstead, E.; Anderson, B.; Martin, R.; Shook, M.; Ziemba, L. D.; Beyersdorf, A. J.; Corr, C.

2017-12-01

A new in situ spectral aerosol extinction instrument (custom built, SpEx) built to cover the 300-700 nm range at 1 nm spectral resolution and temporal resolution of 4 minutes was deployed on the top deck ( 10 m above the water surface) of the R/V Onnuri during the KORUS-OC research cruise around South Korea in spring 2016. This new instrument was one component of a suite of in situ aerosol optical measurements that included 3-visible-wavelength scattering (Airphoton IN101 Nephelometer, at 450, 532, & 632 nm) and absorption (Brechtel Tricolor Absorption Photometer Model 2901, at 467, 528, & 652 nm) with sub-minute temporal resolution; two sets of filters (Teflon and glass fiber, both collected over 3 hour daytime and 12 hour overnight intervals) to provide aerosol absorption spectra over the same wavelength range as SpEx. The glass fiber filters were placed in the center of an integrating sphere (Labsphere DRA-CA-30) attached to a dual beam spectrophotometer (Cary 100 Bio UV-Visible Spectrophotometer) to measure total aerosol absorption spectra via an established method used by the ocean color community to obtain absorption spectra from particles suspended in sea water. Adapting this methodology for atmospheric aerosol measurements provides a new avenue to obtain spectral total aerosol absorption, particularly useful for expanding in situ measurement capabilities into the UV range. The Teflon filters were cut in half with one half extracted in deionized water and the other half extracted in methanol. The solutions were filtered and injected into a liquid waveguide capillary cell (World Precision Instruments LWCC-3100, 100 cm pathlength) to measure the absorption spectra for each solution. In addition, the water extracts were measured via ion chromatography (Dionex ICS-3000 Ion Chromatography System) to obtain water-soluble inorganic ion concentrations, as well as via aerosol mass spectrometry (Aerodyne Research, Inc. HR-ToF High Resolution Aerosol Mass Spectrometer

Water vapor absorption in the atmospheric window at 239 GHz

NASA Technical Reports Server (NTRS)

Bauer, A.; Godon, M.; Carlier, J.; Ma, Q.

1995-01-01

Absolute absorption rates of pure water vapor and mixtures of water vapor and nitrogen have been measured in the atmospheric window at 239 GHz. The dependence on pressure as well as temperature has been obtained. The experimental data are compared with several theoretical or empirical models, and satisfactory agreement is obtained with the models involving a continuum; in the case of pure water vapor, the continuum contribution based upon recent theoretical developments gives good results. The temperature dependence is stronger than that proposed in a commonly used atmospheric transmission model.

Search for ionisation density effects in the radiation absorption stage in LiF:Mg,Ti.

PubMed

Nail, I; Horowitz, Y S; Oster, L; Brandan, M E; Rodríguez-Villafuerte, M; Buenfil, A E; Ruiz-Trejo, C; Gamboa-Debuen, I; Avila, O; Tovar, V M; Olko, P; Ipe, N

2006-01-01

Optical absorption (OA) dose-response of LiF:Mg,Ti (TLD-100) is studied as a function of electron energy (ionisation density) and irradiation dose. Contrary to the situation in thermoluminescence dose-response where the supralinearity is strongly energy-dependent, no dependence of the OA dose filling constants on energy is observed. This result is interpreted as indicating a lack of competitive process in the radiation absorption stage. The lack of an energy dependence of the dose filling constant also suggests that the charge carrier migration distances are sufficiently large to smear out the differences in the non-uniform distribution of ionisation events created by the impinging gamma/electron radiation of various energies.

Water dynamics of Ser-His-Glu-Cys-Asn powder and effects of moisture absorption on its chemical properties.

PubMed

Lin, Songyi; Xue, Peiyu; Yang, Shuailing; Li, Xingfang; Dong, Xiuping; Chen, Feng

2017-08-01

This study has elucidated moisture dynamics in the soybean peptide, Ser-His-Glu-Cys-Asn (SHECN) powder by using dynamic vapor sorption (DVS) and nuclear magnetic resonance (NMR). We also tried to investigate the effects of moisture absorption on the biological activity and chemical properties of SHECN with some effective methods such as mid-infrared (MIR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). DVS results showed that the moisture absorption of SHECN could reach a maximum of 33%, and the SHECN powder after synthesis actually existed in a trihydrate state of SHECN.3H 2 O. Low-field NMR revealed that three water proportions including strong combined water, binding water and bulk water were involved in SHECN moisture absorption and absored water dominantly existed in the form of combined water. Magnetic resonance imaging (MRI) and MIR spectroscopy results indicated that moisture absorption could change the morphology and structure of SHECN. After moisture absorption at 50% and 75% relative humidity, 19 volatiles were identified by GC-MS analysis. Additionally, this study showed that a part of reductive groups in SHECN was oxidized and its antioxidant ability declined significantly (P < 0.05) after moisture absorption. Water absorbed into SHECN powder can significantly change its microstructure and cause its activity to decrease. We must prevent SHECN from absorbing moisture during storage because the water can accelerate the oxidation of samples and promote microbial reactions. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Near-infrared diode laser absorption diagnostic for temperature and water vapor in a scramjet combustor

NASA Astrophysics Data System (ADS)

Liu, Jonathan T. C.; Rieker, Gregory B.; Jeffries, Jay B.; Gruber, Mark R.; Carter, Campbell D.; Mathur, Tarun; Hanson, Ronald K.

2005-11-01

Tunable diode laser absorption measurements of gas temperature and water concentration were made at the exit of a model scramjet combustor fueled on JP-7. Multiplexed, fiber-coupled, near-infrared distributed feedback lasers were used to probe three water vapor absorption features in the 1.34 1.47 μm spectral region (2v1 and v1+v3 overtone bands). Ratio thermometry was performed using direct-absorption wavelength scans of isolated features at a 4-kHz repetition rate, as well as 2f wavelength modulation scans at a 2-kHz scan rate. Large signal-to-noise ratios demonstrate the ability of the optimally engineered optical hardware to reject beam steering and vibration noise. Successful measurements were made at full combustion conditions for a variety of fuel/air equivalence ratios and at eight vertical positions in the duct to investigate spatial uniformity. The use of three water vapor absorption features allowed for preliminary estimates of temperature distributions along the line of sight. The improved signal quality afforded by 2f measurements, in the case of weak absorption, demonstrates the utility of a scanned wavelength modulation strategy in such situations.

Control of pulmonary absorption of water-soluble compounds by various viscous vehicles.

PubMed

Yamamoto, Akira; Yamada, Keigo; Muramatsu, Hideaki; Nishinaka, Asako; Okumura, Shigeki; Okada, Naoki; Fujita, Takuya; Muranishi, Shozo

2004-09-10

Effects of various viscous vehicles on the pulmonary absorption of water-soluble drugs were examined by an in situ pulmonary absorption experiment. Gelatin, polyvinylacohol (PVA), hydroxypropylcellose (HPC), chondroitin sulfate A sodium salt (CS), polyacrylic acid (PAA), methylcellulose #400 (MC400) and hyaluronic acid sodium salt (HA) were used as models of viscous vehicles. 5(6)-Carboxyfluorescein (CF) and fluorescein isothiocayanate-labeled dextran with an average molecular weight of 4000 (FD4) were used as water-soluble drugs. The plasma concentration of CF was controlled and regulated in the presence of these viscous vehicles, especially gelatin (1-5%) and polyvinyl alcohol (PVA) 1%. In the pharmacokinetic analysis, the Cmax values of CF significantly decreased, and its Tmax values increased in the presence of these viscous vehicles compared with the control. The MRT and MAT values of CF with these vehicles were significantly higher than those without these vehicles. Therefore, these findings indicated that the viscous vehicles were effective to regulate the absorption rate of CF. On the other hand, the pulmonary absorption of FD4 was not so much affected even in the presence of gelatin and PVA, although PVA slightly decreased MRT value, and significantly decreased Tmax value. Furthermore, we examined the release rate of CF from the cellulose tube containing various concentrations of gelatin. The release rate of CF from the cellulose tube with gelatin was inversely related to the viscosity of gelatin. In addition, the release rate of CF was inversely related to DeltaMAT (DeltaMAT = MATgel(MAT with gelatin)-MATsol(MAT without gelatin)) in the presence of varying concentrations of gelatin. These findings indicated that these viscous vehicles were effective to control the pulmonary absorption of CF, a water-soluble drug with low molecular weight and they might be useful to increase the local concentration of drugs in the lung.

A simple method to incorporate water vapor absorption in the 15 microns remote temperature sounding

NASA Technical Reports Server (NTRS)

Dallu, G.; Prabhakara, C.; Conhath, B. J.

1975-01-01

The water vapor absorption in the 15 micron CO2 band, which can affect the remotely sensed temperatures near the surface, are estimated with the help of an empirical method. This method is based on the differential absorption properties of the water vapor in the 11-13 micron window region and does not require a detailed knowledge of the water vapor profile. With this approach Nimbus 4 IRIS radiance measurements are inverted to obtain temperature profiles. These calculated profiles agree with radiosonde data within about 2 C.

Analysis and parameterization of absorption properties of northern Norwegian coastal water

NASA Astrophysics Data System (ADS)

Nima, Ciren; Frette, Øyvind; Hamre, Børge; Erga, Svein Rune; Chen, Yi-Chun; Zhao, Lu; Sørensen, Kai; Norli, Marit; Stamnes, Knut; Muyimbwa, Dennis; Ssenyonga, Taddeo; Ssebiyonga, Nicolausi; Stamnes, Jakob J.

2017-02-01

Coastal water bodies are generally classified as Case 2 water, in which non-algal particles (NAP) and colored dissolved organic matter (CDOM) contribute significantly to the optical properties in addition to phytoplankton. These three constituents vary independently in Case 2 water and tend to be highly variable in space and time. We present data from measurements and analyses of the spectral absorption due to CDOM, total suspended matter (TSM), phytoplankton, and NAP in high-latitude northern Norwegian coastal water based on samples taken in spring, summer, and autumn.

Five-Photon Absorption and Selective Enhancement of Multiphoton Absorption Processes

PubMed Central

2015-01-01

We study one-, two-, three-, four-, and five-photon absorption of three centrosymmetric molecules using density functional theory. These calculations are the first ab initio calculations of five-photon absorption. Even- and odd-order absorption processes show different trends in the absorption cross sections. The behavior of all even- and odd-photon absorption properties shows a semiquantitative similarity, which can be explained using few-state models. This analysis shows that odd-photon absorption processes are largely determined by the one-photon absorption strength, whereas all even-photon absorption strengths are largely dominated by the two-photon absorption strength, in both cases modulated by powers of the polarizability of the final excited state. We demonstrate how to selectively enhance a specific multiphoton absorption process. PMID:26120588

Five-Photon Absorption and Selective Enhancement of Multiphoton Absorption Processes.

PubMed

Friese, Daniel H; Bast, Radovan; Ruud, Kenneth

2015-05-20

We study one-, two-, three-, four-, and five-photon absorption of three centrosymmetric molecules using density functional theory. These calculations are the first ab initio calculations of five-photon absorption. Even- and odd-order absorption processes show different trends in the absorption cross sections. The behavior of all even- and odd-photon absorption properties shows a semiquantitative similarity, which can be explained using few-state models. This analysis shows that odd-photon absorption processes are largely determined by the one-photon absorption strength, whereas all even-photon absorption strengths are largely dominated by the two-photon absorption strength, in both cases modulated by powers of the polarizability of the final excited state. We demonstrate how to selectively enhance a specific multiphoton absorption process.

Differential absorption radar techniques: water vapor retrievals

NASA Astrophysics Data System (ADS)

Millán, Luis; Lebsock, Matthew; Livesey, Nathaniel; Tanelli, Simone

2016-06-01

Two radar pulses sent at different frequencies near the 183 GHz water vapor line can be used to determine total column water vapor and water vapor profiles (within clouds or precipitation) exploiting the differential absorption on and off the line. We assess these water vapor measurements by applying a radar instrument simulator to CloudSat pixels and then running end-to-end retrieval simulations. These end-to-end retrievals enable us to fully characterize not only the expected precision but also their potential biases, allowing us to select radar tones that maximize the water vapor signal minimizing potential errors due to spectral variations in the target extinction properties. A hypothetical CloudSat-like instrument with 500 m by ˜ 1 km vertical and horizontal resolution and a minimum detectable signal and radar precision of -30 and 0.16 dBZ, respectively, can estimate total column water vapor with an expected precision of around 0.03 cm, with potential biases smaller than 0.26 cm most of the time, even under rainy conditions. The expected precision for water vapor profiles was found to be around 89 % on average, with potential biases smaller than 77 % most of the time when the profile is being retrieved close to surface but smaller than 38 % above 3 km. By using either horizontal or vertical averaging, the precision will improve vastly, with the measurements still retaining a considerably high vertical and/or horizontal resolution.

Correlation between water absorption and mechanical properties of polyamide 6 filled with layered double hydroxides (LDH)

NASA Astrophysics Data System (ADS)

Botan, R.; Pinheiro, I. F.; Ferreira, F. V.; Lona, L. M. F.

2018-06-01

Polyamide 6 (PA6)/layered double hydroxide (LDH) nanocomposites were prepared by in situ polymerization with different amount (1, 2, 3 wt%) and type (Zn/Cr-L and Zn/Cr-P) of LDHs. The thermal and mechanical properties and water absorption capacity of PA6/LDH nanocomposites were investigated and have shown that the addition of LDHs increases the crystallinity of the polymer and improves their mechanical properties, while decreases the water absorption capacity due to a barrier effect of LDHs. A correlation between mechanical properties and water absorption capacity was observed and discussed. This study provides new strategies for tuning PA6-based nanocomposite properties, leading a progress in the development on the advanced polymer materials.

Changes in water absorptivity of slag based cement mortars exposed to sulphur-oxidising A. thiooxidans bacteria

NASA Astrophysics Data System (ADS)

Estokova, A.; Smolakova, M.; Luptakova, A.; Strigac, J.

2017-10-01

Water absorptivity is heavily influenced by the volume and connectivity of pores in the pore network of cement composites and has been used as an important parameter for quantifying their durability. To improve the durability and permeability of mortars, various mineral admixtures such as furnace slag, silica fume or fly ash are added into the mortar and concrete mixtures. These admixtures provide numerous important advantages such as corrosion control, improvement of mechanical and physical properties and better workability. This study investigated the changes in absorptivity of cement mortars with different amounts of mineral admixture, represented by granulated blast furnace slag, under aggressive bacterial influence. The water absorptivity of mortars specimens exposed to sulphur-oxidising bacteria A. thiooxidans for the period of 3 and 6 months has changed due to bio-corrosion-based degradation process. The differences in water absorptivity in dependence on the mortars composition have been observed.

Retrieval of canopy water content of different crop types with two new hyperspectral indices: Water Absorption Area Index and Depth Water Index

NASA Astrophysics Data System (ADS)

Pasqualotto, Nieves; Delegido, Jesús; Van Wittenberghe, Shari; Verrelst, Jochem; Rivera, Juan Pablo; Moreno, José

2018-05-01

Crop canopy water content (CWC) is an essential indicator of the crop's physiological state. While a diverse range of vegetation indices have earlier been developed for the remote estimation of CWC, most of them are defined for specific crop types and areas, making them less universally applicable. We propose two new water content indices applicable to a wide variety of crop types, allowing to derive CWC maps at a large spatial scale. These indices were developed based on PROSAIL simulations and then optimized with an experimental dataset (SPARC03; Barrax, Spain). This dataset consists of water content and other biophysical variables for five common crop types (lucerne, corn, potato, sugar beet and onion) and corresponding top-of-canopy (TOC) reflectance spectra acquired by the hyperspectral HyMap airborne sensor. First, commonly used water content index formulations were analysed and validated for the variety of crops, overall resulting in a R2 lower than 0.6. In an attempt to move towards more generically applicable indices, the two new CWC indices exploit the principal water absorption features in the near-infrared by using multiple bands sensitive to water content. We propose the Water Absorption Area Index (WAAI) as the difference between the area under the null water content of TOC reflectance (reference line) simulated with PROSAIL and the area under measured TOC reflectance between 911 and 1271 nm. We also propose the Depth Water Index (DWI), a simplified four-band index based on the spectral depths produced by the water absorption at 970 and 1200 nm and two reference bands. Both the WAAI and DWI outperform established indices in predicting CWC when applied to heterogeneous croplands, with a R2 of 0.8 and 0.7, respectively, using an exponential fit. However, these indices did not perform well for species with a low fractional vegetation cover (<30%). HyMap CWC maps calculated with both indices are shown for the Barrax region. The results confirmed the

Water vapor-nitrogen absorption at CO2 laser frequencies

NASA Technical Reports Server (NTRS)

Peterson, J. C.; Thomas, M. E.; Nordstrom, R. J.; Damon, E. K.; Long, R. K.

1979-01-01

The paper reports the results of a series of pressure-broadened water vapor absorption measurements at 27 CO2 laser frequencies between 935 and 1082 kaysers. Both multiple traversal cell and optoacoustic (spectrophone) techniques were utilized together with an electronically stabilized CW CO2 laser. Comparison of the results obtained by these two methods shows remarkable agreement, indicating a precision which has not been previously achieved in pressure-broadened studies of water vapor. The data of 10.59 microns substantiate the existence of the large (greater than 200) self-broadening coefficients determined in an earlier study by McCoy. In this work, the case of water vapor in N2 at a total pressure of 1 atm has been treated.

Modeling L2,3-Edge X-ray Absorption Spectroscopy with Real-Time Exact Two-Component Relativistic Time-Dependent Density Functional Theory.

PubMed

Kasper, Joseph M; Lestrange, Patrick J; Stetina, Torin F; Li, Xiaosong

2018-04-10

X-ray absorption spectroscopy is a powerful technique to probe local electronic and nuclear structure. There has been extensive theoretical work modeling K-edge spectra from first principles. However, modeling L-edge spectra directly with density functional theory poses a unique challenge requiring further study. Spin-orbit coupling must be included in the model, and a noncollinear density functional theory is required. Using the real-time exact two-component method, we are able to variationally include one-electron spin-orbit coupling terms when calculating the absorption spectrum. The abilities of different basis sets and density functionals to model spectra for both closed- and open-shell systems are investigated using SiCl 4 and three transition metal complexes, TiCl 4 , CrO 2 Cl 2 , and [FeCl 6 ] 3- . Although we are working in the real-time framework, individual molecular orbital transitions can still be recovered by projecting the density onto the ground state molecular orbital space and separating contributions to the time evolving dipole moment.

Absorption of Sunlight by Water Vapor in Cloudy Conditions: A Partial Explanation for the Cloud Absorption Anomaly

NASA Technical Reports Server (NTRS)

Crisp, D.

1997-01-01

The atmospheric radiative transfer algorithms used in most global general circulation models underestimate the globally-averaged solar energy absorbed by cloudy atmospheres by up to 25 W/sq m. The origin of this anomalous absorption is not yet known, but it has been attributed to a variety of sources including oversimplified or missing physical processes in these models, uncertainties in the input data, and even measurement errors. Here, a sophisticated atmospheric radiative transfer model was used to provide a more comprehensive description of the physical processes that contribute to the absorption of solar radiation by the Earth's atmosphere. We found that the amount of sunlight absorbed by a cloudy atmosphere is inversely proportional to the solar zenith angle and the cloud top height, and directly proportional to the cloud optical depth and the water vapor concentration within the clouds. Atmospheres with saturated, optically-thick, low clouds absorbed about 12 W/sq m more than clear atmospheres. This accounts for about 1/2 to 1/3 of the anomalous ab- sorption. Atmospheres with optically thick middle and high clouds usually absorb less than clear atmospheres. Because water vapor is concentrated within and below the cloud tops, this absorber is most effective at small solar zenith angles. An additional absorber that is distributed at or above the cloud tops is needed to produce the amplitude and zenith angle dependence of the observed anomalous absorption.

Nano-sized water-in-oil-in-water emulsion enhances intestinal absorption of calcein, a high solubility and low permeability compound.

PubMed

Koga, Kenjiro; Takarada, Nobuo; Takada, Kanji

2010-02-01

Our goal was to develop safe and stable multilayer emulsions capable of enhancing intestinal absorption of biopharmaceutics classification system (BCS) class III drugs. First, w/o emulsions were prepared using calcein as a model BCS class III compound and condensed ricinoleic acid tetraglycerin ester as a hydrophobic emulsifier. Then water-in-oil-in-water (w/o/w) emulsions were prepared with shirasu porous glass (SPG) membranes. Particle size analyses and calcein leakage from oil droplets in w/o/w emulsions led us to select stearic acid hexaglycerin esters (HS-11) and Gelucire 44/14 as hydrophilic emulsifiers. Analyses of the absorption-enhancing effects of w/o/w emulsions on intestinal calcein absorption in rats showed that calcein bioavailability after intraduodenal (i.d.) administration of HS-11 or Gelucire 44/14+polyvinyl alcohol (PVA) w/o/w emulsions prepared with 0.1-microm pore-sized SPGs was significantly higher than that of the calcein control. However, serum calcein concentration vs. time profiles after i.d. administration of w/o/w emulsions prepared with 1.1-microm and 30-microm pore-sized SPGs and an emulsion prepared with a calcein-containing outer water phase were comparable to control profiles. These results suggested that HS-11 or Gelucire 44/14+PVA are safe outer water phase additives and that 0.1-microm pore-sized SPGs are important for preparing w/o/w emulsions that enhanced intestinal calcein absorption. Copyright (c) 2009 Elsevier B.V. All rights reserved.

DETERMINING BERYLLIUM IN DRINKING WATER BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROSCOPY

EPA Science Inventory

A direct graphite furnace atomic absorption spectroscopy method for the analysis of beryllium in drinking water has been derived from a method for determining beryllium in urine. Ammonium phosphomolybdate and ascorbic acid were employed as matrix modifiers. The matrix modifiers s...

Tensile strength and water absorption of alumina filled poly (methyl methacrylate) denture base material.

PubMed

Nizam, A; Mohamed, S H; Arifin, A; Mohd Ishak, Z A; Samsudin, A R

2004-05-01

The aim of this study was to evaluate the tensile properties and water absorption of denture base material prepared from high molecular weight poly methyl methacrylate (PMMA) and alumina (Al2O3) as particulate filler. Specimens for mechanical testing were prepared by adding composite powder to the monomer followed by hand mixing as in dental laboratory procedure. The tensile strength of the prepared denture base material was slightly higher than commercial denture base material, while the water absorption was almost the same for all formulation of denture base materials.

Interaction between Bisphosphonates and Mineral Water: Study of Oral Risedronate Absorption in Rats.

PubMed

Itoh, Akihisa; Akagi, Yuuki; Shimomura, Hitoshi; Aoyama, Takao

2016-01-01

Bisphosphonates are antiosteoporotic agents prescribed for patients with osteoporosis. Drug package inserts for bisphosphonate supplements indicate that their bioavailability is reduced by high levels of metal cations (Ca(2+), Mg(2+), etc.). However, standards for these cations in water used for taking risedronate have not been defined. Here, we examined the effect of calcium and magnesium in mineral waters on the bioavailability of the third-generation bisphosphonate, risedronate, following oral administration in rats. As risedronate is unchanged and eliminated renally, risedronate absorption was estimated from the amount excreted in the urine. Risedronate was dissolved in mineral water samples and administered orally at 0.35 mg/kg. Urine samples were collected for 24 h after dosing. Risedronate was extracted from urine using ion-pair solid-phase cartridges and quantified by HPLC with UV detection (262 nm). Cumulative recovery of risedronate was calculated from the amount excreted in the urine. The 24-h recovery of risedronate from evian® (0.32±0.02% [mean±standard deviation (S.D.)], n=4) and Contrex(®) (0.22±0.05%) mineral waters was significantly lower than that from tap water (0.47±0.04%, p<0.01). Absorption of risedronate in calcium chloride and magnesium chloride aqueous solutions of the same hardness (822 mg/L) was 54% (0.27±0.04%) and 12% (0.51±0.08%) lower, respectively, compared with ultrapure water; suggesting that absorption of risedronate declines as the calcium concentration of mineral waters increases. Consumption of mineral waters containing high levels of calcium (80 mg/L or above), such as evian® and Contrex(®), is therefore not recommended when taking risedronate.

Determination of the water vapor continuum absorption by THz-TDS and Molecular Response Theory.

PubMed

Yang, Yihong; Mandehgar, Mahboubeh; Grischkowsky, D

2014-02-24

Determination of the water vapor continuum absorption from 0.35 to 1 THz is reported. The THz pulses propagate though a 137 m long humidity-controlled chamber and are measured by THz time-domain spectroscopy (THz-TDS). The average relative humidity along the entire THz path is precisely obtained by measuring the difference between transit times of the sample and reference THz pulses to an accuracy of 0.1 ps. Using the measured total absorption and the calculated resonance line absorption with the Molecular Response Theory lineshape, based on physical principles and measurements, an accurate continuum absorption is obtained within four THz absorption windows, that agrees well with the empirical theory. The absorption is significantly smaller than that obtained using the van Vleck-Weisskopf lineshape with a 750 GHz cut-off.

A study on flexural and water absorption of surface modified rice husk flour/E-glass/polypropylene hybrid composite

NASA Astrophysics Data System (ADS)

Rassiah, K.; Sin, T. W.; Ismail, M. Z.

2016-10-01

This work is to study the effects of rice husk (RH)/E-Glass (EG)/polypropylene (PP) hybrid composites in terms of flexural and water absorption properties. The tests conducted are the flexural test and also the water absorption test using two types of water: distilled and sea water. The hybrid composites are prepared with various ratios of fibre weight fractions and the rice husk is treated using 2% Sodium Hydroxide (NaOH) to improve interaction and adhesion between the non-polar matrix and the polar lignocellulosic fibres. It was found that the content of rice husk/E-Glass fillers affected the structural integrity and flexural properties of hybrid composites. In addition, a higher ratio of rice husk contributes to higher water absorption in the hybrid composites.

Enhancement of intestinal water absorption and sodium transport by glycerol in rats.

PubMed

Wapnir, R A; Sia, M C; Fisher, S E

1996-12-01

Glycerol (Gly) is a hydrophilic, absorbable, and energy-rich solute that could make water absorption more efficient. We investigated the use of Gly in a high-energy beverage containing corn syrup (CS) by using a small intestine perfusion procedure in the rat, an approach shown earlier to provide good preclinical information. The effectiveness of several formulations with Gly and CS was compared with commercial products and to experimental formulas where Gly substituted for glucose (Glc). The CS-Gly combination was more effective than preparations on the market containing sucrose and Glc-fructose syrups (G-P and G-L, respectively) in maintaining a net water absorption balance in the test jejunal segment [CS-Gly = 0.21 +/- 0.226, G-L = -1.516 +/- 0.467, and G-P = -0.299 +/- 0.106 (SE) microliter.min-1.cm-1 (P = 0.0113)] and in reducing sodium release into the lumen [CS-Gly = -133.2 +/- 16.2, G-L = -226.7 +/- 25.2, and G-P = -245.6 +/- 23.4 nmol.min-1.cm-1 (P = 0.0022)]. In other preparations, at equal CS concentrations (60 and 80 g/l, respectively), Gly clearly improved net water absorption over a comparable Glc-containing product [CS60-Gly = 0.422 +/- 0.136 and CS80-Gly = 0.666 +/- 0.378 vs. CS60-Glc = -0.282 +/- 0.200 and CS80-Glc = -1.046 +/- 0.480 microliters.min-1.cm-1 (P = 0.0019)]. On the basis of the data of this rat intestine perfusion model, Gly could be a useful ingredient in energy-rich beverages and might enhance fluid absorption in humans.

The Maximum Density of Water.

ERIC Educational Resources Information Center

Greenslade, Thomas B., Jr.

1985-01-01

Discusses a series of experiments performed by Thomas Hope in 1805 which show the temperature at which water has its maximum density. Early data cast into a modern form as well as guidelines and recent data collected from the author provide background for duplicating Hope's experiments in the classroom. (JN)

A summary of transition probabilities for atomic absorption lines formed in low-density clouds

NASA Technical Reports Server (NTRS)

Morton, D. C.; Smith, W. H.

1973-01-01

A table of wavelengths, statistical weights, and excitation energies is given for 944 atomic spectral lines in 221 multiplets whose lower energy levels lie below 0.275 eV. Oscillator strengths were adopted for 635 lines in 155 multiplets from the available experimental and theoretical determinations. Radiation damping constants also were derived for most of these lines. This table contains the lines most likely to be observed in absorption in interstellar clouds, circumstellar shells, and the clouds in the direction of quasars where neither the particle density nor the radiation density is high enough to populate the higher levels. All ions of all elements from hydrogen to zinc are included which have resonance lines longward of 912 A, although a number of weaker lines of neutrals and first ions have been omitted.

[Influence of mineral water on absorption of oral alendronate in rats].

PubMed

Akagi, Yuuki; Sakaue, Tomoyuki; Yoneyama, Eiji; Aoyama, Takao

2011-01-01

Alendronate, an oral bisphosphonate (e.g., Fosamax(®)), is effective in the treatment of osteoporosis, and the Fosamax(®) package insert advises that the bioavailability is reduced when taken with mineral water containing high levels of metal cations (Ca(2+), Mg(2+), etc.). However, standards regarding the water used when taking alendronate are unclear. In this study, the influence of mineral water on the absorption of oral alendronate was investigated based on urinary excretion of its unchanged form in rats. Alendronate was diluted in each water sample and administered orally (0.7 mg/kg) to male Wistar rats after 24-hour fast. Urine samples were collected until 24 h after dosing. Urine samples were alkalinized, and alendronate in urine was precipitated as a calcium salt, followed by loading on an anion exchange cartridge. Eluted alendronate was derivatized with 9-fluorenylmethoxycarbonyl (Fmoc) chloride and determined by HPLC with fluorescent detection. Cumulative urinary excretion recoveries of alendronate were calculated from the amounts of urinary excretion. Alendronate was rapidly excreted in the first 6 h, and similar elimination rate constants were seen (from 0.28 to 0.45 h(-1/2)) among the water samples. Cumulative urinary excretion recoveries with tap water, evian(®) and 100% deep ocean water were 0.98±0.17%, 0.80±0.18% and 1.01±0.16% (mean±S.E., n=4). Those with Contrex(®) (0.33±0.07%) were significantly lower when compared with ultrapure water (1.56±0.35%, p<0.01). These findings suggest that the absorption of alendronate decreases based on the calcium concentration of mineral water. In conclusion, mineral water containing high levels of calcium is not recommended when alendronate is taken.

Determination of absorption coefficient of Chlorella vulgaris and Arthrospira maxima in water

NASA Astrophysics Data System (ADS)

Tekiner, Murat; Kurt, Mustafa; Ak, Ilknur; Kurt, Arzu

2018-02-01

Safe drinking water is crucial for human healthy, nowadays all drinking and irrigation water in developed country commonly come from dams. The water is transported to our usage area by several type of pipe or water-trench. The water can be infected some bacteria such as Chlorella vulgaris, Arthrospira maxima, during this transportation. In this study, we determine which wavelength effect to these green algae and cyanobacteria. For different concentration of these microorganisms in water, we determined uv-vis spectrum. By analyzing these spectrums, we determined absorption coefficient of these microorganisms for selected wavelength. The results show which wavelength can be used for destroy these microorganisms in affected water.

A correlation between secondary structure and rheological properties of low-density lipoproteins at air/water interfaces.

PubMed

Khattari, Ziad

2017-09-01

The secondary structure of apolipoprotein B-100 is studied within the bulk phase and at the air/water interface. In these "in viro" experiments, infrared reflection absorption spectroscopy (IRRAS) study was performed at the air/water interface while circular dichroism (CD) was conducted in the bulk phase. In the bulk phase, the conformational structure containing a significant amount of β-structure, whereas varying amount of α-helix, unordered structures, and β-sheet were observed at the air/water interface depending on the low-density lipoprotein (LDL) film interfacial pressure. The present IRRAS results demonstrate the importance of interfacial pressure-induced structural conformations on the apoB-100. A correlation between the secondary structure of the apoB-100 protein and the monomolecular film elasticity at the air/water interface was also established. The orientation of apoB-100 with respect to the LDL film-normal was found to depend on the interfacial pressure exhibited by the monomolecular film. These results may shed light on LDL's pivotal role in the progression of atherosclerotic coronary artery disease as demonstrated previously by clinical trials.

Absorption of acoustic waves by sunspots. II - Resonance absorption in axisymmetric fibril models

NASA Technical Reports Server (NTRS)

Rosenthal, C. S.

1992-01-01

Analytical calculations of acoustic waves scattered by sunspots which concentrate on the absorption at the magnetohydrodynamic Alfven resonance are extended to the case of a flux-tube embedded in a uniform atmosphere. The model is based on a flux-tubes of varying radius that are highly structured, translationally invariant, and axisymmetric. The absorbed fractional energy is determined for different flux-densities and subphotospheric locations with attention given to the effects of twist. When the flux is highly concentrated into annuli efficient absorption is possible even when the mean magnetic flux density is low. The model demonstrates low absorption at low azimuthal orders even in the presence of twist which generally increases the range of wave numbers over which efficient absorption can occur. Resonance absorption is concluded to be an efficient mechanism in monolithic sunspots, fibril sunspots, and plage fields.

Multi-epoch Detections of Water Ice Absorption in Edge-on Disks around Herbig Ae Stars: PDS 144N and PDS 453

NASA Astrophysics Data System (ADS)

Terada, Hiroshi; Tokunaga, Alan T.

2017-01-01

We report the multi-epoch detections of water ice in 2.8-4.2 μ {{m}} spectra of two Herbig Ae stars, PDS 144N (A2 IVe) and PDS 453 (F2 Ve), which have an edge-on circumstellar disk. The detected water ice absorption is found to originate from their protoplanetary disks. The spectra show a relatively shallow absorption of water ice of around 3.1 μ {{m}} for both objects. The optical depths of the water ice absorption are ˜0.1 and ˜0.2 for PDS 144N and PDS 453, respectively. Compared to the water ice previously detected in low-mass young stellar objects with an edge-on disk with a similar inclination angle, these optical depths are significantly lower. It suggests that stronger UV radiation from the central stars effectively decreases the water ice abundance around the Herbig Ae stars through photodesorption. The water ice absorption in PDS 453 shows a possible variation of the feature among the six observing epochs. This variation could be due to a change of absorption materials passing through our line of sight to the central star. The overall profile of the water ice absorption in PDS 453 is quite similar to the absorption previously reported in the edge-on disk object d216-0939, and this unique profile may be seen only at a high inclination angle in the range of 76°-80°.

IR Absorption Coefficients for the Quantification of Water in Hydrous Ringwoodite

NASA Astrophysics Data System (ADS)

Thomas, Sylvia-Monique; Jacobsen, Steven D.; Bina, Craig R.; Smyth, Joseph R.; Frost, Daniel J.

2010-05-01

Raman spectroscopy, combined with the 'Comparator technique' has been developed to determine water contents ranging from a few wt ppm to wt% in glasses and nominally anhydrous minerals including garnets, olivine, and SiO2 polymorphs (Thomas et al. 2009). The routine is one promising example of quantification tools to determine mineral specific molar absorption coefficients (ɛ) for IR spectroscopy. Mineral specific absorption coefficients are required because general IR calibrations do not necessarily apply to minerals with water incorporated as hydroxyl point defects. Here we utilize the 'Comparator technique' to provide ɛ-values for a set of synthetic Fe-free (Fo100) and Fe-bearing (Fo90, Fo87, Fo83, Fo60) ringwoodites, as well as for γ-Mg2GeO4. Ringwoodite is considered one of the major phases of the Earth's lower transition zone (520-660 km depth) and the knowledge of its absolute water storage capacity is essential for modeling the Earth's deep water cycle. Samples were synthesized at variable P-T conditions in a multi-anvil press and cover a range of OH contents. Single-crystals were characterized using X-ray diffraction and IR spectroscopy. Mineral specific IR absorption coefficients were calculated from independently determined water contents from Raman spectroscopy. Unpolarized IR spectra of Mg-ringwoodite show broad absorption features in the OH region with band maxima at ~2350, 2538, 3130, 3172, 3598 and 3688 cm-1. In the spectra of Fe-bearing ringwoodite and γ-Mg2GeO4 the maxima of the main OH band are shifted to 3244 cm-1 (Fo60) and 3207 cm-1, respectively. For Mg-ringwoodite with the mean wavenumber (area-weighted average of the peak position) of 3170 cm-1 an ɛ-value of 191500 ± 38300 L cm-2/ molH2O was determined. For the ringwoodites with Fo90, Fo87 and Fo83 composition and the mean wavenumbers of 3229 cm-1, 3252 cm-1 and 3163 cm-1 values of 123600 ± 24700 L cm-2/ molH2O, 176300 ± 52900 L cm-2/ molH2O and 155000 ± 46500 L cm-2/ molH2O were

Stopping-power and mass energy-absorption coefficient ratios for Solid Water.

PubMed

Ho, A K; Paliwal, B R

1986-01-01

The AAPM Task Group 21 protocol provides tables of ratios of average restricted stopping powers and ratios of mean energy-absorption coefficients for different materials. These values were based on the work of Cunningham and Schulz. We have calculated these quantities for Solid Water (manufactured by RMI), using the same x-ray spectra and method as that used by Cunningham and Schulz. These values should be useful to people who are using Solid Water for high-energy photon calibration.

Influence of Aloe vera on water absorption and enzymatic in vitro degradation of alginate hydrogel films.

PubMed

Pereira, Rúben F; Carvalho, Anabela; Gil, M H; Mendes, Ausenda; Bártolo, Paulo J

2013-10-15

This study investigates the influence of Aloe vera on water absorption and the in vitro degradation rate of Aloe vera-Ca-alginate hydrogel films, for wound healing and drug delivery applications. The influence of A. vera content (5%, 15% and 25%, v/v) on water absorption was evaluated by the incubation of the films into a 0.1 M HCl solution (pH 1.0), acetate buffer (pH 5.5) and simulated body fluid solution (pH 7.4) during 24h. Results show that the water absorption is significantly higher for films containing high A. vera contents (15% and 25%), while no significant differences are observed between the alginate neat film and the film with 5% of A. vera. The in vitro enzymatic degradation tests indicate that an increase in the A. vera content significantly enhances the degradation rate of the films. Control films, incubated in a simulated body fluid solution without enzymes, are resistant to the hydrolytic degradation, exhibiting reduced weight loss and maintaining its structural integrity. Results also show that the water absorption and the in vitro degradation rate of the films can be tailored by changing the A. vera content. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of water volume based on water absorption and mixing time on physical properties of tapioca starch – wheat composite bread

NASA Astrophysics Data System (ADS)

Prameswari, I. K.; Manuhara, G. J.; Amanto, B. S.; Atmaka, W.

2018-05-01

Tapioca starch application in bread processing change water absorption level by the dough, while sufficient mixing time makes the optimal water absorption. This research aims to determine the effect of variations in water volume and mixing time on physical properties of tapioca starch – wheat composite bread and the best method for the composite bread processing. This research used Complete Randomized Factorial Design (CRFD) with two factors: variations of water volume (111,8 ml, 117,4 ml, 123 ml) and mixing time (16 minutes, 17 minutes 36 seconds, 19 minutes 12 seconds). The result showed that water volume significantly affected on dough volume, bread volume and specific volume, baking expansion, and crust thickness. Mixing time significantly affected on dough volume and specific volume, bread volume and specific volume, baking expansion, bread height, and crust thickness. While the combination of water volume and mixing time significantly affected for all physical properties parameters except crust thickness.

Compressive Strength and Water Absorption of Pervious Concrete that Using the Fragments of Ceramics and Roof Tiles

NASA Astrophysics Data System (ADS)

Prahara, E.; Meilani

2014-03-01

Pervious concrete was introduced in America in 2003, popularized by Dan Brown and used as a rigid pavement in the open parking lot. Rigid pavement using pervious concrete can absorb water in the surface to go straight through the concrete to the ground below.This water flow is one of the benefit of using the pervious concrete. Using of wastes such as broken roof and ceramics tiles are not commonly used in Indonesia. Utilization these kind of wastes is predicted lower the compressive strength of pervious concrete as they are used as a substitute for coarse aggregate.In this research, pervious concrete is made using a mixture of the fragment of ceramics and roof tiles.This research using broken ceramics and roof tiles with a grain size that loose from 38 mm sieve, retained on 19 mm sieve and the coarse aggregate from crushed stone that loose 12.5 mm sieve, retained on 9.5 mm sieve. The water cement ratio is 0.3 and to assist the mixing process, the addition of addictive in pervious concrete is used.The size of coarse aggregate used in the mixture affects the strength of pervious concrete. The larger the size of aggregate, the obtained compressive strength becomes smaller. It also affects the density of pervious concrete. The using of mixture of ceramics and roof tiles only reduce 2 MPa of pervious concrete compressive strength so this mixture can be used as a substitute for coarse aggregate with a maximum portion of 30 %. The high porosity of the specimens causes the reduction of pervious concrete density that affect the compressive strength. This high level of porosity can be seen from the high level of water absorption that exceed the required limit of water infiltration.

Quantification of the dynamic changes in the absorption coefficient of liquid water at erbium:YAG and carbon dioxide laser wavelengths

NASA Astrophysics Data System (ADS)

Shori, Ramesh K.

The interaction of high-intensity, short-pulsed radiation with liquid water results in dynamic changes in the optical absorption coefficient of water. These changes and their implications, as related to mid-infrared laser ablation of tissue, were not investigated until the late 1980's and early 1990's. Classical models of absorption and heating do not explain the dynamic, non-linear changes in water. The objective of the present work was to quantify the dynamic changes in the absorption coefficient of liquid water as a function of incident energy at three clinically relevant infrared wavelengths (λ = 2.94, 9.6, 10.6 μm). To investigate the changes in the absorption spectrum of water in the 3-μm band, a stable, high-energy Q- switched Er:YAG laser emitting 2.94-μm radiation in a near-perfect TEMoo spatial beam profile was developed. Key to the development of this laser was careful attention to the gain medium, optical pump system, system optics, and the thermal system. The final system design was capable of emitting 110 mJ/pulse at of 2-4 Hz with a lamp lifetime exceeding 12 million pulses The laser was used in two sets of experiments in order to quantify the above changes. First, the laser was used to measure the velocity of the shock front produced by vaporizing a gelatin-based tissue phantom. The measured shock velocity was related to the optical energy absorbed by the tissue phantom and the absorption coefficient, based on the pressure relationships derived using a 1-D piston model for an expanding plume. The shock front velocity measurements indicate that the absorption coefficient is constant for incident fluences less than 20 J/cm2, a result consistent with transmission data. For higher fluences, the data indicate a decrease in the absorption coefficient, which is again consistent with transmission data. Quantification of the absorption coefficient can, however, not be made without violating assumptions that form the basis for the 1-D piston model. Second

Modelling the light absorption coefficients of oceanic waters: Implications for underwater optical applications

NASA Astrophysics Data System (ADS)

Prabhakaran, Sai Shri; Sahu, Sanjay Kumar; Dev, Pravin Jeba; Shanmugam, Palanisamy

2018-05-01

Spectral absorption coefficients of particulate (algal and non-algal components) and dissolved substances are modelled and combined with the pure seawater component to determine the total light absorption coefficients of seawater in the Bay of Bengal. Two parameters namely chlorophyll-a (Chl) concentration and turbidity were measured using commercially available instruments with high sampling rates. For modelling the light absorption coefficients of oceanic waters, the measured data are classified into two broad groups - algal dominant and non-algal particle (NAP) dominant. With these criteria the individual absorption coefficients of phytoplankton and NAP were established based on their concentrations using an iterative method. To account for the spectral dependence of absorption by phytoplankton, the wavelength-dependent coefficients were introduced into the model. The CDOM absorption was determined by subtracting the individual absorption coefficients of phytoplankton and NAP from the measured total absorption data and then related to the Chl concentration. Validity of the model is assessed based on independent in-situ data from certain discrete locations in the Bay of Bengal. The total absorption coefficients estimated using the new model by considering the contributions of algal, non-algal and CDOM have good agreement with the measured total absorption data with the error range of 6.9 to 28.3%. Results obtained by the present model are important for predicting the propagation of the radiant energy within the ocean and interpreting remote sensing observation data.

Absorption by H2O and H2O-N2 mixtures at 153 GHz

NASA Technical Reports Server (NTRS)

Bauer, A.; Godon, M.; Carlier, J.; Ma, Q.; Tippings, R. H.

1993-01-01

New experimental data on and a theoretical analysis of the absorption coefficient at 153 GHz are presented for pure water vapor and water vapor-nitrogen mixtures. This frequency is 30 GHz lower than the resonant frequency of the nearest strong water line (183 GHz) and complements our previous measurements at 213 GHz. The pressure dependence is observed to be quadratic in the case of pure water vapor, while in the case of mixtures there are both linear and quadratic density components. By fitting our experimental data taken at several temperatures we have obtained the temperature dependence of the absorption. Our experimental data are compared to several theoretical models with and without a continuum contribution, and we find that none of the models is in very good agreement with the data; in the case of pure water vapor, the continuum contribution calculated using the recent theoretical absorption gives the best results. In general, the agreement between the data and the various models is less satisfactory than found previously in the high-frequency wing. The anisotropy in the observed absorption differs from that currently used in atmospheric models.

Correlation between octanol/water and liposome/water distribution coefficients and drug absorption of a set of pharmacologically active compounds.

PubMed

Esteves, Freddy; Moutinho, Carla; Matos, Carla

2013-06-01

Absorption and consequent therapeutic action are key issues in the development of new drugs by the pharmaceutical industry. In this sense, different models can be used to simulate biological membranes to predict the absorption of a drug. This work compared the octanol/water and the liposome/water models. The parameters used to relate the two models were the distribution coefficients between liposomes and water and octanol and water and the fraction of drug orally absorbed. For this study, 66 drugs were collected from literature sources and divided into four groups according to charge and ionization degree: neutral; positively charged; negatively charged; and partially ionized/zwitterionic. The results show a satisfactory linear correlation between the octanol and liposome systems for the neutral (R²= 0.9324) and partially ionized compounds (R²= 0.9367), contrary to the positive (R²= 0.4684) and negatively charged compounds (R²= 0.1487). In the case of neutral drugs, results were similar in both models because of the high fraction orally absorbed. However, for the charged drugs (positively, negatively, and partially ionized/zwitterionic), the liposomal model has a more-appropriate correlation with absorption than the octanol model. These results show that the neutral compounds only interact with membranes through hydrophobic bonds, whereas charged drugs favor electrostatic interactions established with the liposomes. With this work, we concluded that liposomes may be a more-appropriate biomembrane model than octanol for charged compounds.

Capacity for absorption of water-soluble secondary metabolites greater in birds than in rodents.

PubMed

Karasov, William H; Caviedes-Vidal, Enrique; Bakken, Bradley Hartman; Izhaki, Ido; Samuni-Blank, Michal; Arad, Zeev

2012-01-01

Plant secondary metabolites (SMs) are pervasive in animal foods and potentially influence feeding behavior, interspecies interactions, and the distribution and abundance of animals. Some of the major classes of naturally occurring SMs in plants include many water-soluble compounds in the molecular size range that could cross the intestinal epithelium via the paracellular space by diffusion or solvent drag. There are differences among species in paracellular permeability. Using Middle Eastern rodent and avian consumers of fruits containing SMs, we tested the hypothesis that avian species would have significantly higher paracellular permeability than rodent species. Permeability in intact animals was assessed using standard pharmacological methodology to measure absorption of two radiolabeled, inert, neutral water-soluble probes that do not interact with intestinal nutrient transporters, L-arabinose (M(r) = 150.1 Da) and lactulose (M(r) = 342.3 Da). We also measured absorption of labeled 3-O-methyl-D-glucose (3OMD-glucose; M(r) = 194.2 Da), which is a nonmetabolized analogue of D-glucose that is passively absorbed through the paracellular space but also transported across the enterocyte membranes. Most glucose was absorbed by all species, but arabinose fractional absorption (f) was nearly three times higher in birds (1.03±0.17, n = 15 in two species) compared to rodents (0.37±0.06, n = 10 in two species) (P<0.001). Surprisingly, the apparent rates of absorption in birds of arabinose exceeded those of 3OMD-glucose. Our findings are in agreement with previous work showing that the paracellular pathway is more prominent in birds relative to nonflying mammals, and suggests that birds may be challenged by greater absorption of water-soluble, dietary SMs. The increased expression of the paracellular pathway in birds hints at a tradeoff: the free energy birds gain by absorbing water-soluble nutrients passively may be offset by the metabolic demands

Water Absorption and Thickness Swelling Behavior of Polypropylene Reinforced with Hybrid Recycled Newspaper and Glass Fiber

NASA Astrophysics Data System (ADS)

Shakeri, Alireza; Ghasemian, Ali

2010-04-01

This study aims to investigate the moisture absorption of recycled newspaper fiber and recycled newspaper-glass fiber hybrid reinforced polypropylene composites to study their suitability in outdoor applications. In this work composite materials were made from E-glass fiber (G), recycled newspaper (NP) and polypropylene (PP), by using internal mixing and hot-pressing molding. Long-term water absorption (WA) and thickness swelling (TS) kinetics of the composites was investigated with water immersion. It was found that the WA and TS increase with NP content in composite and water immersion time before an equilibrium condition was reached. Composites made from the NP show comparable results as those made of the hybrid fiber. The results suggest that the water absorption and thickness swelling composite decrease with increasing glass fiber contents in hybrid fiber composite. It is interesting to find that the WA and TS can be reduced significantly with incorporation of a coupling agent (maleated polypropylene) in the composite formulation. Further studies were conducted to model the water diffusion and thickness swelling of the composites. Diffusion coefficients and swelling rate parameters in the models were obtained by fitting the model predictions with the experimental data.

Waterfowl density on agricultural fields managed to retain water in winter

USGS Publications Warehouse

Twedt, D.J.; Nelms, C.O.

1999-01-01

Managed water on private and public land provides habitat for wintering waterfowl in the Mississippi Valley, where flood control projects have reduced the area of natural flooding. We compared waterfowl densities on rice, soybean, and moist-soil fields under cooperative agreements to retain water from 1 November through 28 February in Arkansas and Mississippi and assessed temporal changes in waterfowl density during winter in 1991-1992 and 1992-1993. Fields flooded earlier in Arkansas, but retained water later in Mississippi. Over winter, waterfowl densities decreased in Arkansas and increased in Mississippi. Densities of waterfowl, including mallard (Anas platyrhynchos), the most abundant species observed, were greatest on moist-soil fields. However, soybean fields had the greatest densities of northern shoveler (Spatula clypeata).

Influence of absorption by environmental water vapor on radiation transfer in wildland fires

Treesearch

D. Frankman; B. W. Webb; B. W. Butler

2008-01-01

The attenuation of radiation transfer from wildland flames to fuel by environmental water vapor is investigated. Emission is tracked from points on an idealized flame to locations along the fuel bed while accounting for absorption by environmental water vapor in the intervening medium. The Spectral Line Weighted-sum-of-gray-gases approach was employed for treating the...

Self-interaction-corrected time-dependent density-functional-theory calculations of x-ray-absorption spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tu, Guangde; Rinkevicius, Zilvinas; Vahtras, Olav

We outline an approach within time-dependent density functional theory that predicts x-ray spectra on an absolute scale. The approach rests on a recent formulation of the resonant-convergent first-order polarization propagator [P. Norman et al., J. Chem. Phys. 123, 194103 (2005)] and corrects for the self-interaction energy of the core orbital. This polarization propagator approach makes it possible to directly calculate the x-ray absorption cross section at a particular frequency without explicitly addressing the excited-state spectrum. The self-interaction correction for the employed density functional accounts for an energy shift of the spectrum, and fully correlated absolute-scale x-ray spectra are thereby obtainedmore » based solely on optimization of the electronic ground state. The procedure is benchmarked against experimental spectra of a set of small organic molecules at the carbon, nitrogen, and oxygen K edges.« less

Mid-IR absorption sensing of heavy water using a silicon-on-sapphire waveguide.

PubMed

Singh, Neetesh; Casas-Bedoya, Alvaro; Hudson, Darren D; Read, Andrew; Mägi, Eric; Eggleton, Benjamin J

2016-12-15

We demonstrate a compact silicon-on-sapphire (SOS) strip waveguide sensor for mid-IR absorption spectroscopy. This device can be used for gas and liquid sensing, especially to detect chemically similar molecules and precisely characterize extremely absorptive liquids that are difficult to detect by conventional infrared transmission techniques. We reliably measure concentrations up to 0.25% of heavy water (D₂O) in a D₂O-H₂O mixture at its maximum absorption band at around 4 μm. This complementary metal-oxide-semiconductor (CMOS) compatible SOS D₂O sensor is promising for applications such as measuring body fat content or detection of coolant leakage in nuclear reactors.

Surface force and vibrational spectroscopic analyses of interfacial water molecules in the vicinity of methoxy-tri(ethylene glycol)-terminated monolayers: mechanisms underlying the effect of lateral packing density on bioinertness.

PubMed

Sekine, Taito; Asatyas, Syifa; Sato, Chikako; Morita, Shigeaki; Tanaka, Masaru; Hayashi, Tomohiro

Unequivocal dependence of bioinertness of self-assembled monolayers of methoxy-tri(ethylene glycol)-terminated alkanethiol (EG3-OMe SAMs) on their packing density has been a mystery for more than two decades. We tackled this long-standing question by performing surface force and surface-enhanced infrared absorption (SEIRA) spectroscopic measurements. Our surface force measurements revealed a physical barrier of interfacial water in the vicinity of the Au-supported EG3-OMe SAM (low packing density), whereas the Ag-supported one (high packing density) did not possess such interfacial water. In addition, the results of SEIRA measurements clearly exhibited that hydrogen bonding states of the interfacial water differ depending on the substrates. We also characterized the bioinertness of these SAMs by protein adsorption tests and adhesion assays of platelet and human umbilical vein endothelial cells. The hydrogen bonding states of the interfacial water and water-induced interaction clearly correlated with the bioinertness of the SAMs, suggesting that the interfacial water plays an important role determining the interaction of the SAMs with biomolecules and cells.

How Does Tree Density Affect Water Loss of Peatlands? A Mesocosm Experiment

PubMed Central

Limpens, Juul; Holmgren, Milena; Jacobs, Cor M. J.; Van der Zee, Sjoerd E. A. T. M.; Karofeld, Edgar; Berendse, Frank

2014-01-01

Raised bogs have accumulated more atmospheric carbon than any other terrestrial ecosystem on Earth. Climate-induced expansion of trees and shrubs may turn these ecosystems from net carbon sinks into sources when associated with reduced water tables. Increasing water loss through tree evapotranspiration could potentially deepen water tables, thus stimulating peat decomposition and carbon release. Bridging the gap between modelling and field studies, we conducted a three-year mesocosm experiment subjecting natural bog vegetation to three birch tree densities, and studied the changes in subsurface temperature, water balance components, leaf area index and vegetation composition. We found the deepest water table in mesocosms with low tree density. Mesocosms with high tree density remained wettest (i.e. highest water tables) whereas the control treatment without trees had intermediate water tables. These differences are attributed mostly to differences in evapotranspiration. Although our mesocosm results cannot be directly scaled up to ecosystem level, the systematic effect of tree density suggests that as bogs become colonized by trees, the effect of trees on ecosystem water loss changes with time, with tree transpiration effects of drying becoming increasingly offset by shading effects during the later phases of tree encroachment. These density-dependent effects of trees on water loss have important implications for the structure and functioning of peatbogs. PMID:24632565

Evidence of low-density and high-density liquid phases and isochore end point for water confined to carbon nanotube

PubMed Central

Nomura, Kentaro; Kaneko, Toshihiro; Bai, Jaeil; Francisco, Joseph S.; Yasuoka, Kenji; Zeng, Xiao Cheng

2017-01-01

Possible transition between two phases of supercooled liquid water, namely the low- and high-density liquid water, has been only predicted to occur below 230 K from molecular dynamics (MD) simulation. However, such a phase transition cannot be detected in the laboratory because of the so-called “no-man’s land” under deeply supercooled condition, where only crystalline ices have been observed. Here, we show MD simulation evidence that, inside an isolated carbon nanotube (CNT) with a diameter of 1.25 nm, both low- and high-density liquid water states can be detected near ambient temperature and above ambient pressure. In the temperature–pressure phase diagram, the low- and high-density liquid water phases are separated by the hexagonal ice nanotube (hINT) phase, and the melting line terminates at the isochore end point near 292 K because of the retracting melting line from 292 to 278 K. Beyond the isochore end point (292 K), low- and high-density liquid becomes indistinguishable. When the pressure is increased from 10 to 600 MPa along the 280-K isotherm, we observe that water inside the 1.25-nm-diameter CNT can undergo low-density liquid to hINT to high-density liquid reentrant first-order transitions. PMID:28373562

[Water balance of different density artificial Caragana microphylla shrubs in Horqin sand land].

PubMed

Lamusa, A; Longjun, C I; Yang, Xiaohui; Jiang, Deming

2006-01-01

Employing water balance equation, this paper estimated the evapotranspiration of different density Caragana microphylla shrubs during their growing season. The results showed that during this season, the soil water content under artificial C. microphylla shrubs decreased with their increasing planting density. The average soil water content of 0.5 m x 1 m and 1 m x 2 m density artificial C. microphylla shrubs was below wilting humidity (1.55%), while that of 2 m x 2 m density and natural shrubs was kept above 1.60% which could meet the demand of shrubs growth. The evapotranspiration increased with increasing planting densities, being the highest (297.81 mm) in 0.5 m x 1 m density artificial C. microphylla shrubs, which accounted for 97.90% of the total rainfall during growing season, and the lowest (279.71 mm) in 2 m x 2 m density shrubs. By the end of growth phase, soil water content had a surplus of 24.49 mm. According to the soil water status and water balance theory, the appropriate planting density of C. microphylla shrubs in Horqin sand land should be 2 m x 2 m.

Enhancement of the grafting performance and of the water absorption of cassava starch graft copolymer by gamma radiation

NASA Astrophysics Data System (ADS)

Kiatkamjornwong, Suda; Meechai, Nispa

1997-06-01

Enhancement of the gamma radiation grafting of acrylonitrile onto gelatinized cassava starch was investigated. Infrared spectrometry was used to follow the chemical changes in the grafting reaction and from saponification. The saponified starch- g-PAN (HSPAN) was then characterized in terms of grafting parameters to provide a guide for the optimum total dose (kGy) and the appropriate ratio of starch/acrylonitrile for a fixed dose rate of 2.5 × 10 -1 kGy/min. Other dose rates were also carried out to obtain the appropriate result of grafting copolymerization and of water absorption. A thin aluminium foil, covering the inner wall of the reaction vessel, was found to be far more effective than any other metal films in the enhancement of the grafting reaction and the water absorption as well. Nitric acid in the medium increases the grafting yield and the water absorption. Methyl ether hydroquinone inhibitor was evaluated for its ability to increase homopolymerization and decrease graft reaction. When styrene was used as a comonomer, it hampered the grafting of acrylonitrile onto starch backbone. The water absorption capacity was improved by freeze-drying the HSPAN. The treatment of the HSPAN with aluminium trichloride hexahydrate was found to enhance the degree of wicking, but to decrease the water absorbency.

The effect of water absorption on the dielectric properties of polyethylene hexagonal boron nitride nanocomposites

NASA Astrophysics Data System (ADS)

Ayoob, Raed; Alhabill, Fuad N.; Andritsch, Thomas; Vaughan, Alun S.

2018-02-01

The effect of water absorption on the dielectric response of polyethylene/hexagonal boron nitride nanocomposites has been studied by dielectric spectroscopy. The nanocomposites have been prepared with hBN concentrations ranging from 2 wt% to 30 wt%. Fourier transform infrared spectroscopy and thermogravimetric analysis revealed a very small amount of hydroxyl groups on the surface of hBN. Mass loss measurements showed that the nanocomposites did not absorb any water under ambient and dry conditions while there was some water absorption under wet conditions. The dielectric spectroscopy results showed a broad relaxation peak, indicative of different states of water with water shells of different thickness, which moved to higher frequencies with increasing water content. However, the dielectric losses were significantly lower than the losses reported in the literature of nanocomposites under wet conditions. In addition, all the absorbed water was successfully removed under vacuum conditions which demonstrated that the interactions between the water and the nanocomposites were very weak, due to the hydrophobic nature of the hBN surface. This is a highly useful property, when considering these materials for applications in electrical insulation.

Light absorption coefficients by phytoplankton pigments, suspended particles and colored dissolved organic matter in the Crimea coastal water (the Black sea) in June 2016

NASA Astrophysics Data System (ADS)

Moiseeva, N.; Churilova, T.; Efimova, T.; Krivenko, O.; Latushkin, A.

2017-11-01

Variability of the bio-optical properties of the Crimean coastal waters in June 2016 has been analyzed. The type of vertical distribution chlorophyll a concentration and phytoplankton light absorption coefficients and spectra shape differed between shallow and deeper water. In the deeper water seasonal stratification divided euphotic zone into layers with different environmental conditions. In the deeper part of the euphotic zone (below the thermocline) phytoplankton absorption spectra had local maximum at 550 nm, which was likely to be associated with high abundance of cyanobacteria (Synechococcus sps.) in the phytoplankton community. The concentration of chlorophyll a specific light absorption coefficient of phytoplankton decreased with depth (especially pronounced in the blue domain of the spectrum). In the shallow water the vertical distributions of all absorption properties were relatively homogeneous due to vertical water mixing. In the shallow water non-algal particles light absorption coefficient and its contribution to total particulate absorption were higher than those in the deeper water. The non-algal particles (NAP) and colored dissolved organic matter (CDOM) light absorption spectra were well described by an exponential function with a slope averaging 0.010 nm-1 (SD = 0.001 nm-1) and 0.022 nm-1 (SD = 0.0060 nm-1), correspondingly. The CDOM absorption at 440 nm and slope coefficient varied significantly across the investigated area, which was possibly associated with the terrestrial influences. The assessment of the contribution of phytoplankton, NAP and CDOM to total light absorption showed that CDOM dominated in the absorption at 440 nm.

Compressive strength, flexural strength and water absorption of concrete containing palm oil kernel shell

NASA Astrophysics Data System (ADS)

Noor, Nurazuwa Md; Xiang-ONG, Jun; Noh, Hamidun Mohd; Hamid, Noor Azlina Abdul; Kuzaiman, Salsabila; Ali, Adiwijaya

2017-11-01

Effect of inclusion of palm oil kernel shell (PKS) and palm oil fibre (POF) in concrete was investigated on the compressive strength and flexural strength. In addition, investigation of palm oil kernel shell on concrete water absorption was also conducted. Total of 48 concrete cubes and 24 concrete prisms with the size of 100mm × 100mm × 100mm and 100mm × 100mm × 500mm were prepared, respectively. Four (4) series of concrete mix consists of coarse aggregate was replaced by 0%, 25%, 50% and 75% palm kernel shell and each series were divided into two (2) main group. The first group is without POF, while the second group was mixed with the 5cm length of 0.25% of the POF volume fraction. All specimen were tested after 7 and 28 days of water curing for a compression test, and flexural test at 28 days of curing period. Water absorption test was conducted on concrete cube age 28 days. The results showed that the replacement of PKS achieves lower compressive and flexural strength in comparison with conventional concrete. However, the 25% replacement of PKS concrete showed acceptable compressive strength which within the range of requirement for structural concrete. Meanwhile, the POF which should act as matrix reinforcement showed no enhancement in flexural strength due to the balling effect in concrete. As expected, water absorption was increasing with the increasing of PKS in the concrete cause by the porous characteristics of PKS

Evaluation about wettability, water absorption or swelling of excipients through various methods and the correlation between these parameters and tablet disintegration.

PubMed

Yang, Baixue; Wei, Chen; Yang, Yang; Wang, Qifang; Li, Sanming

2018-04-06

To evaluate parameters about wettability, water absorption or swelling of excipients in forms of powders or dosage through various methods systematically and explore its correlation with tablet disintegration. The water penetration and swelling of powders with different proportions of excipients including microcrystalline cellulose (MCC), mannitol, low-substituted hydroxypropyl cellulose (L-HPC), crospolyvinylpyrrolidone (PVPP), carboxymethyl starch sodium (CMS-Na), croscarmellose sodium (CCMC-Na) and magnesium stearate (MgSt) were determined by Washburn capillary rise. Both contact angle of water on the excipient compacts and surface swelling volume were measured by sessile drop technique. Moreover, the test about water absorption and swelling of compacts was fulfilled by a modified method. Eventually, the disintegration of tablets with or without loratadine was performed according to the method described in USP. These parameters were successfully identified by the methods above, which proved that excipient wettability or swelling properties varied with the structure of excipients. For example, MgSt could improve the water uptake, while impeded tablet swelling. Furthermore, in the present study it is verified that tablet disintegration was closely related to these parameters, especially wetting rate and initial water absorption rate. The higher wetting rate of water on tablet or initial water absorption rate, the faster swelling it be, resulting in the shorter tablet disintegration time. The methods utilized in the present study were feasible and effective. The disintegration of tablets did relate to these parameters, especially wetting rate and initial water absorption rate.

Self-Supported Copper Oxide Electrocatalyst for Water Oxidation at Low Overpotential and Confirmation of Its Robustness by Cu K-edge X-ray Absorption Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xiang; Cui, Shengsheng; Sun, Zijun

Developing efficient water oxidation catalysts made of earth-abundant elements is a demanding challenge that should be met to fulfill the promise of water splitting for clean energy. Herein we report an annealing approach to synthesize binder-free, self-supported heterogeneous copper oxide (CuO) on conductive electrodes for oxygen evolution reaction (OER), producing electrodes with excellent electrocatalytic properties such as high efficiency, low overpotential, and good stability. The catalysts were grown in situ on fluorine-doped tin oxide (FTO) by electrodeposition from a simple Cu(II) salt solution, followed by annealing at a high temperature. Under optimal conditions, the CuO-based OER catalyst shows an onsetmore » potential of <0.58 V (vs Ag/AgCl) in 1.0 M KOH at pH 13.6. From the Tafel plot, the required overpotentials for current densities of 0.1 and 1.0 mA/cm2 are only 360 and 430 mV, respectively. The structure and the presence of a CuO motif in the catalyst have been identified by high-energy X-ray diffraction (HE-XRD), Cu K-edge X-ray absorption (XAS) spectra including X-ray absorption near-edge structure (XANES), and extended X-ray absorption fine structure (EXAFS). To the best of our knowledge, this represents the best catalytic activity for CuO-based OER catalysts to date.« less

Real-time monitoring of corks' water absorption using laser speckle temporal correlation

NASA Astrophysics Data System (ADS)

Nassif, Rana; Abou Nader, Christelle; Pellen, Fabrice; Le Jeune, Bernard; Le Brun, Guy; Abboud, Marie

2015-08-01

Physical and mechanical properties of cork allow it solving many types of problems and make it suitable for a wide range of applications. Our objective consists into studying cork's water absorption by analyzing the dynamic speckle field using the temporal correlation method. Experimental results show that the medium was inert at first with the absence of activity, and as the cap cork was more and more immersed into water, the presence of the activity becomes more significant. This temporal parameter revealed the sensibility of biospeckle method to monitor the amount of absorbed water by cork caps.

In-Line Capacitance Sensor for Real-Time Water Absorption Measurements

NASA Technical Reports Server (NTRS)

Nurge, Mark A.; Perusich, Stephen A.

2010-01-01

A capacitance/dielectric sensor was designed, constructed, and used to measure in real time the in-situ water concentration in a desiccant water bed. Measurements were carried out with two experimental setups: (1) passing nitrogen through a humidity generator and allowing the gas stream to become saturated at a measured temperature and pressure, and (2) injecting water via a syringe pump into a nitrogen stream. Both water vapor generating devices were attached to a downstream vertically-mounted water capture bed filled with 19.5 g of Moisture Gone desiccant. The sensor consisted of two electrodes: (1) a 1/8" dia stainless steel rod placed in the middle of the bed and (2) the outer shell of the stainless steel bed concentric with the rod. All phases of the water capture process (background, heating, absorption, desorption, and cooling) were monitored with capacitance. The measured capacitance was found to vary linearly with the water content in the bed at frequencies above 100 kHz indicating dipolar motion dominated the signal; below this frequency, ionic motion caused nonlinearities in the water concentration/capacitance relationship. The desiccant exhibited a dielectric relaxation whose activation energy was lowered upon addition of water indicating either a less hindered rotational motion or crystal reorientation.

Organic fertilizer application increases the soil respiration and net ecosystem carbon dioxide absorption of paddy fields under water-saving irrigation.

PubMed

Yang, Shihong; Xiao, Ya Nan; Xu, Junzeng

2018-04-01

Quantifying carbon sequestration in paddy soil is necessary to understand the effect of agricultural practices on carbon cycles. The objective of this study was to assess the effect of organic fertilizer addition (MF) on the soil respiration and net ecosystem carbon dioxide (CO 2 ) absorption of paddy fields under water-saving irrigation (CI) in the Taihu Lake Region of China during the 2014 and 2015 rice-growing seasons. Compared with the traditional fertilizer and water management (FC), the joint regulation of CI and MF (CM) significantly increased the rice yields and irrigation water use efficiencies of paddy fields by 4.02~5.08 and 83.54~109.97% (p < 0.05). The effects of organic fertilizer addition on soil respiration and net ecosystem CO 2 absorption rates showed inter-annual differences. CM paddy fields showed a higher soil respiration and net CO 2 absorption rates during some periods of the rice growth stage in the first year and during most periods of the rice growth stage in the second year. These fields also had significantly higher total CO 2 emission through soil respiration (total R soil ) and total net CO 2 absorption compared with FC paddy fields (p < 0.05). The total R soil and net ecosystem CO 2 absorption of CM paddy fields were 67.39~91.55 and 129.41~113.75 mol m -2 , which were 27.66~135.52 and 12.96~31.66% higher than those of FC paddy fields. The interaction between water and fertilizer management had significant effects on total net ecosystem CO 2 absorption. The frequent alternate wet-dry cycles of CI paddy fields increased the soil respiration and reduced the net CO 2 absorption. Organic fertilizer promoted the soil respiration of paddy soil but also increased its net CO 2 absorption and organic carbon content. Therefore, the joint regulation of water-saving irrigation and organic fertilizer is an effective measure for maintaining yield, increasing irrigation water use efficiency, mitigating CO 2 emission, and promoting paddy

Water absorption characteristics of novel Cu/LDPE nanocomposite for use in intrauterine devices.

PubMed

Xia, Xianping; Cai, Shuizhou; Hu, Junhui; Xie, Changsheng

2006-11-01

Intrauterine devices (IUDs), especially the copper-containing IUDs (Cu-IUDs), are one of the worldwide used forms for birth control, owing to their advantages of long-lasting and high efficacy, economy, safety, and reversibility. However, it is not perfect for the existing Cu-IUDs; some shortcomings related to its side effects have not been overcome yet. For this reason, a new Cu-IUDs material, the copper/low-density polyethylene (Cu/LDPE) nanocomposite, has been developed in our research team. The structure and water uptake characteristics of this new Cu-IUDs material have been investigated by using X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and gravimetric analysis in this paper. The results of XRD, SEM, EDS, and FT-IR show three important outcomes associated with the structure of the nanocomposite. First, the nanocomposite is hybrid of the polymer and the copper nanoparticles (nano-Cu). Second, porosities, nano-Cu aggregates, and primary alcohol (R--CH(2)--OH) are existed in the nanocomposite. Third, the nano-Cu aggregates are distributed uniformly in the polymer matrix in general. The results of Gravimetric analysis, which associated with the water uptake characteristics of the nanocomposite, exhibit that the water absorption behavior of the nanocomposite obeys the classical diffusion theory very well, the water uptake of the nanocomposite increases with the increasing of the nano-Cu loading, and that the water uptake ability of the nanocomposite with 15.0 wt % nano-Cu (50 nm in diameter) is about 150 times larger than that of the base resin and about 45 times higher than that of the Cu/LDPE microcomposite with 15.0 wt % copper microparticles (5 microm in diameter). These water uptake characteristics are mainly attributed to the structure of the Cu/LDPE composites and the size effect of the nano-Cu. (c) 2006 Wiley Periodicals, Inc.

X-ray absorption in insulators with non-Hermitian real-time time-dependent density functional theory.

PubMed

Fernando, Ranelka G; Balhoff, Mary C; Lopata, Kenneth

2015-02-10

Non-Hermitian real-time time-dependent density functional theory was used to compute the Si L-edge X-ray absorption spectrum of α-quartz using an embedded finite cluster model and atom-centered basis sets. Using tuned range-separated functionals and molecular orbital-based imaginary absorbing potentials, the excited states spanning the pre-edge to ∼20 eV above the ionization edge were obtained in good agreement with experimental data. This approach is generalizable to TDDFT studies of core-level spectroscopy and dynamics in a wide range of materials.

TPS/PCL composite reinforced with treated sisal fibers: property, biodegradation and water-absorption

USDA-ARS?s Scientific Manuscript database

Sisal fibers bleached with sodium-hydroxide followed by hydrogen peroxide treatment were incorporated in a thermoplastic starch;-polycaprolactone (TPS/PCL) blend via extrusion processing and examined for their property, biodegradability and water-absorption. Scanning electron microscopy revealed wel...

Experimental evidence of low-density liquid water upon rapid decompression

PubMed Central

Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; Shen, Guoyin

2018-01-01

Water is an extraordinary liquid, having a number of anomalous properties which become strongly enhanced in the supercooled region. Due to rapid crystallization of supercooled water, there exists a region that has been experimentally inaccessible for studying deeply supercooled bulk water. Using a rapid decompression technique integrated with in situ X-ray diffraction, we show that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140–165 K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. Together with the change in crystallization rate with temperature, the experimental evidence indicates that the LDN is a low-density liquid (LDL). The measured X-ray diffraction data show that the LDL is tetrahedrally coordinated with the tetrahedral network fully developed and clearly linked to low-density amorphous ices. On the other hand, there is a distinct difference in structure between the LDL and supercooled water or liquid water in terms of the tetrahedral order parameter. PMID:29440411

Bias and uncertainty in the absorption emission measurement of atomic sodium density in the SSME exit plane

NASA Technical Reports Server (NTRS)

Bauman, Leslie E.

1990-01-01

The measurement of atomic sodium concentration in the TTB 019 firing of April 1990 is significant in that it represents the first measurement of density at the exit plane of the space shuttle main engine. The knowledge of the sodium density, combined with the certainty that the exit plane of the plume is optically thin at the sodium D-line wavelengths, provides essential information for evaluation of diagnostic techniques using sodium atoms, such as resonant Doppler velocimetry for temperature, pressure, and velocity through high resolution fluorescent lineshape analysis. The technique used for the sodium atom line transmission (SALT) measurements is that of resonant absorption emission using a hollow cathode lamp as the reference source. Through the use of two-dimensional kinetic (TDK) predictions of temperature and density for the flight engine case and radiative transfer calculations, this line-of-sight spectrally integrated transmission indicates a sodium atom concentration, i.e., mole fraction, of 0.91e-10. The subject of this paper is the assumptions and measurement uncertainties tied into the calculation. Because of the narrow shape of the source emission, the uncertainties in the absorption profile could introduce considerable bias in the measurement. The following were investigated: (1) the inclusion of hyperfine splitting of the D-lines in the calculation; (2) the use of the flight engine predictions of plume temperature and density versus those for the large throat engine; (3) the assumption of a Gaussian, i.e., Doppler, distribution for the source radiance with a temperature of 400 K; (4) the use of atomic collisional shift and width values for the work by Jongerius; and (5) a Doppler shift for a 7 degree outward velocity vector at the plume edge. Also included in the study was the bias introduced by an uncertainty in the measurement of the D1/D2 line ratio in the source.

A polydimethylsiloxane (PDMS) sponge for the selective absorption of oil from water.

PubMed

Choi, Sung-Jin; Kwon, Tae-Hong; Im, Hwon; Moon, Dong-Il; Baek, David J; Seol, Myeong-Lok; Duarte, Juan P; Choi, Yang-Kyu

2011-12-01

We present a sugar-templated polydimethylsiloxane (PDMS) sponge for the selective absorption of oil from water. The process for fabricating the PDMS sponge does not require any intricate synthesis processes or equipment and it is not environmentally hazardous, thus promoting potential in environmental applications. The proposed PDMS sponge can be elastically deformed into any shape, and it can be compressed repeatedly in air or liquids without collapsing. Therefore, absorbed oils and organic solvents can be readily removed and reused by simply squeezing the PDMS sponge, enabling excellent recyclability. Furthermore, through appropriately combining various sugar particles, the absorption capacity of the PDMS sponge is favorably optimized. © 2011 American Chemical Society

Soil water retention of a bare soil with changing bulk densities

USDA-ARS?s Scientific Manuscript database

Tillage changes the bulk density of the soil, lowering the density initially after which it increases as the soil settles. Implications of this for soil water content and soil water potential are obvious, but limited efforts have been made to monitor these changes continuously. We present in-situ me...

Force-detected nanoscale absorption spectroscopy in water at room temperature using an optical trap

NASA Astrophysics Data System (ADS)

Parobek, Alexander; Black, Jacob W.; Kamenetska, Maria; Ganim, Ziad

2018-04-01

Measuring absorption spectra of single molecules presents a fundamental challenge for standard transmission-based instruments because of the inherently low signal relative to the large background of the excitation source. Here we demonstrate a new approach for performing absorption spectroscopy in solution using a force measurement to read out optical excitation at the nanoscale. The photoinduced force between model chromophores and an optically trapped gold nanoshell has been measured in water at room temperature. This photoinduced force is characterized as a function of wavelength to yield the force spectrum, which is shown to be correlated to the absorption spectrum for four model systems. The instrument constructed for these measurements combines an optical tweezer with frequency domain absorption spectroscopy over the 400-800 nm range. These measurements provide proof-of-principle experiments for force-detected nanoscale spectroscopies that operate under ambient chemical conditions.

Fast Time-Dependent Density Functional Theory Calculations of the X-ray Absorption Spectroscopy of Large Systems.

PubMed

Besley, Nicholas A

2016-10-11

The computational cost of calculations of K-edge X-ray absorption spectra using time-dependent density functional (TDDFT) within the Tamm-Dancoff approximation is significantly reduced through the introduction of a severe integral screening procedure that includes only integrals that involve the core s basis function of the absorbing atom(s) coupled with a reduced quality numerical quadrature for integrals associated with the exchange and correlation functionals. The memory required for the calculations is reduced through construction of the TDDFT matrix within the absorbing core orbitals excitation space and exploiting further truncation of the virtual orbital space. The resulting method, denoted fTDDFTs, leads to much faster calculations and makes the study of large systems tractable. The capability of the method is demonstrated through calculations of the X-ray absorption spectra at the carbon K-edge of chlorophyll a, C 60 and C 70 .

Water absorption and moisture permeation properties of chitosan/poly(acrylamide-co-itaconic acid) IPC films.

PubMed

Bajpai, M; Bajpai, S K; Jyotishi, Pooja

2016-03-01

In this work, aqueous solutions of chitosan (Ch) and [poly(acrylamide(AAm)-co-itaconicacid(IA)] have been mixed to yield Ch/poly(AAm-co-IA) Inter-polyelectrolyte complex (IPC) films. The films were characterized by FTIR, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). There was remarkable increase in the crystalline nature of IPC films. The films were investigated for their water absorption capacity in the physiological fluid (PF) of pH 7.4 at 37 °C. The amount of IA present in the film forming solutions affected the water absorption behavior of the resulting films. The dynamic water uptake data were interpreted by various kinetic models. The effect of pH on the swelling ratio (SR) indicated that the films showed highest swelling in lower as well as higher pH media. The water vapor transmission rates (WVTR) were obtained in the range of 6000-6645 g/m(2)/day. Copyright © 2015 Elsevier B.V. All rights reserved.

Enhanced Adsorption of p-Arsanilic Acid from Water by Amine-Modified UiO-67 as Examined Using Extended X-ray Absorption Fine Structure, X-ray Photoelectron Spectroscopy, and Density Functional Theory Calculations.

PubMed

Tian, Chen; Zhao, Jian; Ou, Xinwen; Wan, Jieting; Cai, Yuepeng; Lin, Zhang; Dang, Zhi; Xing, Baoshan

2018-03-20

p-Arsanilic acid ( p-ASA) is an emerging organoarsenic pollutant comprising both inorganic and organic moieties. For the efficient removal of p-ASA, adsorbents with high adsorption affinity are urgently needed. Herein, amine-modified UiO-67 (UiO-67-NH 2 ) metal-organic frameworks (MOFs) were synthesized, and their adsorption affinities toward p-ASA were 2 times higher than that of the pristine UiO-67. Extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculation results revealed adsorption through a combination of As-O-Zr coordination, hydrogen bonding, and π-π stacking, among which As-O-Zr coordination was the dominant force. Amine groups played a significant role in enhancing the adsorption affinity through strengthening the As-O-Zr coordination and π-π stacking, as well as forming new adsorption sites via hydrogen bonding. UiO-67-NH 2 s could remove p-ASA at low concentrations (<5 mg L -1 ) in simulated natural and wastewaters to an arsenic level lower than that of the drinking water standard of World Health Organization (WHO) and the surface water standard of China, respectively. This work provided an emerging and promising method to increase the adsorption affinity of MOFs toward pollutants containing both organic and inorganic moieties, via modifying functional groups based on the pollutant structure to achieve synergistic adsorption effect.

Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhovtobriukh, Iurii; Besley, Nicholas A.; Fransson, Thomas

Here, the connection between specific features in the water X-ray absorption spectrum and X-ray emission spectrum (XES) and the local H-bond coordination is studied based on structures obtained from path-integral molecular dynamics simulations using either the opt-PBE-vdW density functional or the MB-pol force field. Computing the XES spectrum using all molecules in a snapshot results in only one peak in the lone-pair (1b 1) region, while the experiment shows two peaks separated by 0.8-0.9 eV. Different H-bond configurations were classified based on the local structure index (LSI) and a geometrical H-bond cone criterion. We find that tetrahedrally coordinated molecules characterizedmore » by high LSI values and two strong donated and two strong accepted H-bonds contribute to the low energy 1b 1 emission peak and to the post-edge region in absorption. Molecules with the asymmetric H-bond environment with one strong accepted H-bond and one strong donated H-bond and low LSI values give rise to the high energy 1b 1 peak in the emission spectrum and mainly contribute to the pre-edge and main-edge in the absorption spectrum. The 1b 1 peak splitting can be increased to 0.62 eV by imposing constraints on the H-bond length, i.e., for very tetrahedral structures short H-bonds (less than 2.68 Å) and for very asymmetric structures elongated H-bonds (longer than 2.8 Å). Such structures are present, but underrepresented, in the simulations which give more of an average of the two extremes.« less

Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water

DOE PAGES

Zhovtobriukh, Iurii; Besley, Nicholas A.; Fransson, Thomas; ...

2018-04-14

Here, the connection between specific features in the water X-ray absorption spectrum and X-ray emission spectrum (XES) and the local H-bond coordination is studied based on structures obtained from path-integral molecular dynamics simulations using either the opt-PBE-vdW density functional or the MB-pol force field. Computing the XES spectrum using all molecules in a snapshot results in only one peak in the lone-pair (1b 1) region, while the experiment shows two peaks separated by 0.8-0.9 eV. Different H-bond configurations were classified based on the local structure index (LSI) and a geometrical H-bond cone criterion. We find that tetrahedrally coordinated molecules characterizedmore » by high LSI values and two strong donated and two strong accepted H-bonds contribute to the low energy 1b 1 emission peak and to the post-edge region in absorption. Molecules with the asymmetric H-bond environment with one strong accepted H-bond and one strong donated H-bond and low LSI values give rise to the high energy 1b 1 peak in the emission spectrum and mainly contribute to the pre-edge and main-edge in the absorption spectrum. The 1b 1 peak splitting can be increased to 0.62 eV by imposing constraints on the H-bond length, i.e., for very tetrahedral structures short H-bonds (less than 2.68 Å) and for very asymmetric structures elongated H-bonds (longer than 2.8 Å). Such structures are present, but underrepresented, in the simulations which give more of an average of the two extremes.« less

Near infrared study of water-benzene mixtures at high temperatures and pressures.

PubMed

Jin, Yusuke; Ikawa, Shun-Ichi

2004-08-08

Near-infrared absorption of water-benzene mixtures has been measured at temperatures and pressures in the ranges of 473-673 K and 100-400 bar, respectively. Concentrations of water and benzene in the water-rich phase of the mixtures were obtained from the integrated absorption intensities of the OH stretching overtone transition of water and the CH stretching overtone transition of benzene, respectively. Using these concentrations, the densities of the water-rich phase were estimated and compared with the average densities before mixing, which were calculated from literature densities of neat water and neat benzene. It is found that anomalously large volume expansion on the mixing occurs in the region enclosed by an extended line of the three-phase equilibrium curve and the one-phase critical curve of the mixtures, and the gas-liquid equilibrium curve of water. Furthermore, magnitude of the relative volume change increases with decreasing molar fraction of benzene in the present experimental range. It is suggested that dissolving a small amount of benzene in water induces a change in the fluid density from a liquidlike condition to a gaslike condition in the vicinity of the critical region.

Heat convection at the density maximum point of water

NASA Astrophysics Data System (ADS)

Balta, Nuri; Korganci, Nuri

2018-01-01

Water exhibits a maximum in density at normal pressure at around 4° degree temperature. This paper demonstrates that during cooling, at around 4 °C, the temperature remains constant for a while because of heat exchange associated with convective currents inside the water. Superficial approach implies it as a new anomaly of water, but actually it is not.

Heat Convection at the Density Maximum Point of Water

ERIC Educational Resources Information Center

Balta, Nuri; Korganci, Nuri

2018-01-01

Water exhibits a maximum in density at normal pressure at around 4° degree temperature. This paper demonstrates that during cooling, at around 4 °C, the temperature remains constant for a while because of heat exchange associated with convective currents inside the water. Superficial approach implies it as a new anomaly of water, but actually it…

Commercial Absorption Heat Pump Water Heater: Beta Prototype Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geoghegan, Patrick; Ally, Moonis; Sharma, Vishaldeep

2016-10-14

The Beta version of the Commercial Absorption Heat Pump (CAHP) water heater was evaluated in the environmental chambers at Oak Ridge National Laboratory. Ambient air conditions ranged from 17 to 75 oF and inlet water temperatures ranged from 100 to 120oF in order to capture trends in performance. The unit was operated under full fire (100%) and partial fire (55%). The unit was found to perform at 90% of the project goal at the design conditions of 47oF ambient and 100oF water temperatures. The trends across the full range of environmental conditions were as expected for ambient air temperatures abovemore » 32oF. Below this temperature and for the full fire condition, frost accumulated on the evaporator coil. In future work a defrost strategy will be enabled, the unit will be thoroughly cleaned of an oil contamination and the rectifier will be reconfigured in order to meet the design goals and have a field test unit ready in early 2017.« less

Moisture absorption of starch based biocomposites reinforced with water hyacinth fibers

NASA Astrophysics Data System (ADS)

Abral, H.; Hartono, J.

2017-06-01

Bioplastic based on tapioca starch (TSB) is very sensitive on moisture; meanwhile this substance may be used to replace synthetic plastic. This paper reports effect of Water Hyacinth Fibers (WHF) content on performance moisture absorption of starch based biocomposites. WHF content in the TSB matrix was varied in 1, 3, 5, and 10% respectively. The samples were placed in closed room with high relative humidity (RH) of 99% at 250C with different duration for 30 and 960 min respectively. The result showed that moisture absorption in the beginning was increased rapidly, and then achieved a level steady state. After that, significant swelling of the sample occurred for further duration in 960 min. Gradient of the swelling was decreased as increasing the fibers content in the TSB matrix.

Optimization of an exchange-correlation density functional for water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fritz, Michelle; Fernández-Serra, Marivi; Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794-3800

2016-06-14

We describe a method, that we call data projection onto parameter space (DPPS), to optimize an energy functional of the electron density, so that it reproduces a dataset of experimental magnitudes. Our scheme, based on Bayes theorem, constrains the optimized functional not to depart unphysically from existing ab initio functionals. The resulting functional maximizes the probability of being the “correct” parameterization of a given functional form, in the sense of Bayes theory. The application of DPPS to water sheds new light on why density functional theory has performed rather poorly for liquid water, on what improvements are needed, and onmore » the intrinsic limitations of the generalized gradient approximation to electron exchange and correlation. Finally, we present tests of our water-optimized functional, that we call vdW-DF-w, showing that it performs very well for a variety of condensed water systems.« less

Strong water absorption in the dayside emission spectrum of the planet HD 189733b.

PubMed

Grillmair, Carl J; Burrows, Adam; Charbonneau, David; Armus, Lee; Stauffer, John; Meadows, Victoria; van Cleve, Jeffrey; von Braun, Kaspar; Levine, Deborah

2008-12-11

Recent observations of the extrasolar planet HD 189733b did not reveal the presence of water in the emission spectrum of the planet. Yet models of such 'hot-Jupiter' planets predict an abundance of atmospheric water vapour. Validating and constraining these models is crucial to understanding the physics and chemistry of planetary atmospheres in extreme environments. Indications of the presence of water in the atmosphere of HD 189733b have recently been found in transmission spectra, where the planet's atmosphere selectively absorbs the light of the parent star, and in broadband photometry. Here we report the detection of strong water absorption in a high-signal-to-noise, mid-infrared emission spectrum of the planet itself. We find both a strong downturn in the flux ratio below 10 microm and discrete spectral features that are characteristic of strong absorption by water vapour. The differences between these and previous observations are significant and admit the possibility that predicted planetary-scale dynamical weather structures may alter the emission spectrum over time. Models that match the observed spectrum and the broadband photometry suggest that heat redistribution from the dayside to the nightside is weak. Reconciling this with the high nightside temperature will require a better understanding of atmospheric circulation or possible additional energy sources.

The effect of a nanofilled resin-based coating on water absorption by teeth restored with glass ionomer.

PubMed

Hankins, Amanda D; Hatch, Robert H; Benson, Jarred H; Blen, Bernard J; Tantbirojn, Daranee; Versluis, Antheunis

2014-04-01

A nanofilled, resin-based light-cured coating (G-Coat Plus, GC America, Alsip, Ill.) may reduce water absorption by glass ionomers. The authors investigated this possibility by measuring cuspal flexure caused by swelling of glass ionomer-restored teeth. The authors cut large mesio-occlusodistal slots (4-millimeter wide, 4-mm deep) in 12 extracted premolars and restored them with a glass ionomer cement (Fuji IX GP Extra, GC America). Six teeth were coated, and the other six were uncoated controls. The authors digitized the teeth in three dimensions by using an optical scanner after preparation and restoration and during an eight-week storage in water. They calculated cuspal flexure and analyzed the results by using an analysis of variance and Student-Newman-Keuls post hoc tests (significance level .05). They used dye penetration along the interface to verify bonding. Inward cuspal flexure indicated restoration shrinkage. Coated restorations had significantly higher flexure (mean [standard deviation], -11.9 [3.5] micrometers) than did restorations without coating (-7.3 [1.5] μm). Flexure in both groups decreased significantly (P < .05) during water storage and, after eight weeks, it changed to expansion for uncoated control restorations. Dye penetration along the interfaces was not significant, which ruled out debonding as the cause of cuspal relaxation. Teeth restored with glass ionomer cement exhibited shrinkage, as seen by inward cuspal flexure. The effect of the protective coating on water absorption was evident in the slower shrinkage compensation. The study results show that teeth restored with glass ionomers exhibited setting shrinkage that deformed tooth cusps. Water absorption compensated for the shrinkage. Although the coating may be beneficial for reducing water absorption, it also slows the shrinkage compensation rate (that is, the rate that hygroscopic expansion compensates for cuspal flexure from shrinkage).

Toothbrush abrasion of paint-on resins for shade modification and crown resins: effect of water absorption.

PubMed

Fujii, Koichi; Arikawa, Hiroyuki; Kanie, Takahito; Ban, Seiji

2004-06-01

In order to investigate the clinical application of paint-on resins, the effect of water absorption on toothbrush abrasion and light transmittance of ten crown resins including three paint-on resins was examined. Water absorption into each material ranged from 0.29 to 0.89 mg/cm2 after storage in distilled-water for 6 weeks and their hardnesses decreased by 3.5-22.3%. Maximum surface roughness (Rmax) of the materials stored in distilled water for 6 weeks increased with an increasing number of toothbrush abrasion cycles and ranged from 1.9 to 10.5 microm after 100,000 cycles. Also, Maximum depth and weight loss as an indicator of the amount of each material lost by abrasion showed similar behaviors similar to Rmax. These results indicated that the abrasion resistance of paint-on resins was located in the middle among all materials examined.

WVR-GPS comparison measurements and calibration of the 20-32 GHz tropospheric water vapor absorption model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keihm, S. J.; Bar-Server, Y.; Liljegren, J. C.

2002-06-01

Collocated measurements of opacity (from water vapor radiometer brightness temperatures) and wet path delay (from ground-based tracking of global positioning satellites) are used to constrain the model of atmospheric water vapor absorption in the 20-32 GHz band. A differential approach is presented in which the slope of opacity-versus-wet delay data is used as the absorption model constraint. This technique minimizes the effects of radiometric calibration errors and oxygen model uncertainties in the derivation of a best-fit vapor absorption model. A total of approximately five months of data was obtained from two experiment sites. At the Cloud and Radiation Testbed (CART)more » site near Lamont, Oklahoma, three independent water vapor radiometers (WVRs) provided near-continuous opacity measurements over the interval July-September 1998. At the NASA/Goldstone tracking station in the California desert two WVRs; obtained opacity data over the September-October 1997 interval. At both sites a Global Positioning Satellite (GPS) receiver and surface barometer obtained the data required for deriving the zenith wet delays over the same time frames. Measured values of the opacity-versus-wet delay slope parameter were obtained at four WVR frequencies (20.7, 22.2, 23.8, and 31.4 GHz) and compared with predictions of four candidate absorption models referenced in the literature. With one exception, all three models provide agreement within 5% of the opacity-versus-wet delay slope measurements at all WVR frequencies at both sites. One model provides agreement for all channels at both sites to the 2-3% level. This absorption model accuracy level represents a significant improvement over that attainable using radiosondes.« less

Up-cycling waste glass to minimal water adsorption/absorption lightweight aggregate by rapid low temperature sintering: optimization by dual process-mixture response surface methodology.

PubMed

Velis, Costas A; Franco-Salinas, Claudia; O'Sullivan, Catherine; Najorka, Jens; Boccaccini, Aldo R; Cheeseman, Christopher R

2014-07-01

Mixed color waste glass extracted from municipal solid waste is either not recycled, in which case it is an environmental and financial liability, or it is used in relatively low value applications such as normal weight aggregate. Here, we report on converting it into a novel glass-ceramic lightweight aggregate (LWA), potentially suitable for high added value applications in structural concrete (upcycling). The artificial LWA particles were formed by rapidly sintering (<10 min) waste glass powder with clay mixes using sodium silicate as binder and borate salt as flux. Composition and processing were optimized using response surface methodology (RSM) modeling, and specifically (i) a combined process-mixture dual RSM, and (ii) multiobjective optimization functions. The optimization considered raw materials and energy costs. Mineralogical and physical transformations occur during sintering and a cellular vesicular glass-ceramic composite microstructure is formed, with strong correlations existing between bloating/shrinkage during sintering, density and water adsorption/absorption. The diametrical expansion could be effectively modeled via the RSM and controlled to meet a wide range of specifications; here we optimized for LWA structural concrete. The optimally designed LWA is sintered in comparatively low temperatures (825-835 °C), thus potentially saving costs and lowering emissions; it had exceptionally low water adsorption/absorption (6.1-7.2% w/wd; optimization target: 1.5-7.5% w/wd); while remaining substantially lightweight (density: 1.24-1.28 g.cm(-3); target: 0.9-1.3 g.cm(-3)). This is a considerable advancement for designing effective environmentally friendly lightweight concrete constructions, and boosting resource efficiency of waste glass flows.

Water vapor absorption coefficients in the 8-13-micron spectral region - A critical review

NASA Technical Reports Server (NTRS)

Grant, William B.

1990-01-01

Measurements of water vapor absorption coefficients in the thermal IR atmospheric window (8-13 microns) during the past 20 years obtained by a variety of techniques are reviewed for consistency and compared with computed values based on the AFGL spectral data tapes. The methods of data collection considered were atmospheric long path absorption with a CO2 laser or a broadband source and filters, a White cell and a CO2 laser or a broadband source and a spectrometer, and a spectrophone with a CO2 laser. Advantages and disadvantages of each measurement approach are given as a guide to further research. Continuum absorption has apparently been measured accurately to about the 5-10 percent level in five of the measurements reported.

Experimental Evidence of Low Density Liquid Water under Decompression

NASA Astrophysics Data System (ADS)

Shen, G.; Lin, C.; Sinogeikin, S. V.; Smith, J.

2017-12-01

Water is not only the most important substance for life, but also plays important roles in liquid science for its anomalous properties. It has been widely accepted that water's anomalies are not a result of simple thermal fluctuation, but are connected to the formation of various structural aggregates in the hydrogen bonding network. Among several proposed scenarios, one model of fluctuations between two different liquids has gradually gained traction. These two liquids are referred to as a low-density liquid (LDL) and a high-density liquid (HDL) with a coexistence line in the deeply supercooled regime at elevated pressure. The LDL-HDL transition ends with decreasing pressure at a liquid-liquid critical point (LLCP) with its Widom line extending to low pressures. Above the Widom line lies mostly HDL which is favored by entropy, while LDL, mostly lying below the Widom line, is favored by enthalpy in the tetrahedral hydrogen bonding network. The origin of water's anomalies can then be explained by the increase in structural fluctuations, as water is cooled down to deeply supercooled temperatures approaching the Widom line. Because both the LLCP and the LDL-HDL transition line lie in water's "no man's land" between the homogeneous nucleation temperature (TH, 232 K) and the crystallization temperature (TX, 150 K), the success of experiments exploring this region has been limited thus far. Using a rapid decompression technique integrated with in situ x-ray diffraction, we observe that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140-165K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. The change in crystallization rate with temperature indicates that the LDN is a LDL with its tetrahedrally-coordinated network fully developed and clearly linked to low-density amorphous ices. The observation of the tetrahedral LDL supports the two-liquid model for

Development of vacuum ultraviolet absorption spectroscopy system for wide measurement range of number density using a dual-tube inductively coupled plasma light source

NASA Astrophysics Data System (ADS)

Kuwahara, Akira; Matsui, Makoto; Yamagiwa, Yoshiki

2012-12-01

A vacuum ultraviolet absorption spectroscopy system for a wide measurement range of atomic number densities is developed. Dual-tube inductively coupled plasma was used as a light source. The probe beam profile was optimized for the target number density range by changing the mass flow rate of the inner and outer tubes. This system was verified using cold xenon gas. As a result, the measurement number density range was extended from the conventional two orders to five orders of magnitude.

Fabrication of Porous Ceramic-Geopolymer Based Material to Improve Water Absorption and Retention in Construction Materials: A Review

NASA Astrophysics Data System (ADS)

Jamil, N. H.; Ibrahim, W. M. A. W.; Abdullah, M. M. A. B.; Sandu, A. V.; Tahir, M. F. M.

2017-06-01

Porous ceramic nowadays has been investigated for a variety of its application such as filters, lightweight structural component and others due to their specific properties such as high surface area, stability and permeability. Besides, it has the properties of low thermal conductivity. Various formation techniques making these porous ceramic properties can be tailored or further fine-tuned to obtain the optimum characteristic. Porous materials also one of the good candidate for absorption properties. Conventional construction materials are not design to have good water absorption and retention that lead to the poor performance on these criteria. Temperature is a major driving force for moisture movement and influences sorption characteristics of many constructions materials. The effect of elevated temperatures on the water absorption coefficient and retention remain as critical issue that need to be investigated. Therefore, this paper will review the process parameters in fabricating porous ceramic for absorption properties.

Measured performance of a 3 ton LiBr absorption water chiller and its effect on cooling system operation

NASA Technical Reports Server (NTRS)

Namkoong, D.

1976-01-01

A three ton lithium bromide absorption water chiller was tested for a number of conditions involving hot water input, chilled water, and the cooling water. The primary influences on chiller capacity were the hot water inlet temperature and the cooling water inlet temperature. One combination of these two parameters extended the output to as much as 125% of design capacity, but no combination could lower the capacity to below 60% of design. A cooling system was conceptually designed so that it could provide several modes of operation. Such flexibility is needed for any solar cooling system to be able to accommodate the varying solar energy collection and the varying building demand. It was concluded that a three-ton absorption water chiller with the kind of performance that was measured can be incorporated into a cooling system such as that proposed, to provide efficient cooling over the specified ranges of operating conditions.

Measured performance of a 3-ton LiBr absorption water chiller and its effect on cooling system operation

NASA Technical Reports Server (NTRS)

Namkoong, D.

1976-01-01

A 3-ton lithium bromide absorption water chiller was tested for a number of conditions involving hot-water input, chilled water, and the cooling water. The primary influences on chiller capacity were the hot water inlet temperature and the cooling water inlet temperature. One combination of these two parameters extended the output to as much as 125% of design capacity, but no combination could lower the capacity to below 60% of design. A cooling system was conceptually designed so that it could provide several modes of operation. Such flexibility is needed for any solar cooling system to be able to accommodate the varying solar energy collection and the varying building demand. It is concluded that a 3-ton absorption water chiller with the kind of performance that was measured can be incorporated into a cooling system such as that proposed, to provide efficient cooling over the specified ranges of operating conditions.

Photoionization-driven Absorption-line Variability in Balmer Absorption Line Quasar LBQS 1206+1052

NASA Astrophysics Data System (ADS)

Sun, Luming; Zhou, Hongyan; Ji, Tuo; Jiang, Peng; Liu, Bo; Liu, Wenjuan; Pan, Xiang; Shi, Xiheng; Wang, Jianguo; Wang, Tinggui; Yang, Chenwei; Zhang, Shaohua; Miller, Lauren P.

2017-04-01

In this paper we present an analysis of absorption-line variability in mini-BAL quasar LBQS 1206+1052. The Sloan Digital Sky Survey spectrum demonstrates that the absorption troughs can be divided into two components of blueshift velocities of ˜700 and ˜1400 km s-1 relative to the quasar rest frame. The former component shows rare Balmer absorption, which is an indicator of high-density absorbing gas; thus, the quasar is worth follow-up spectroscopic observations. Our follow-up optical and near-infrared spectra using MMT, YFOSC, TSpec, and DBSP reveal that the strengths of the absorption lines vary for both components, while the velocities do not change. We reproduce all of the spectral data by assuming that only the ionization state of the absorbing gas is variable and that all other physical properties are invariable. The variation of ionization is consistent with the variation of optical continuum from the V-band light curve. Additionally, we cannot interpret the data by assuming that the variability is due to a movement of the absorbing gas. Therefore, our analysis strongly indicates that the absorption-line variability in LBQS 1206+1052 is photoionization driven. As shown from photoionization simulations, the absorbing gas with blueshift velocity of ˜700 km s-1 has a density in the range of 109 to 1010 cm-3 and a distance of ˜1 pc, and the gas with blueshift velocity of ˜1400 km s-1 has a density of 103 cm-3 and a distance of ˜1 kpc.

Measurements of near-IR water vapor absorption at high pressure and temperature

NASA Astrophysics Data System (ADS)

Rieker, G. B.; Liu, X.; Li, H.; Jeffries, J. B.; Hanson, R. K.

2007-03-01

Tunable diode lasers (TDLs) are used to measure high resolution (0.1 cm-1), near-infrared (NIR) water vapor absorption spectra at 700 K and pressures up to 30 atm within a high-pressure and -temperature optical cell in a high-uniformity tube furnace. Both direct absorption and wavelength modulation with second harmonic detection (WMS-2f) spectra are obtained for 6 cm-1 regions near 7204 cm-1 and 7435 cm-1. Direct absorption measurements at 700 K and 10 atm are compared with simulations using spectral parameters from HITRAN and a hybrid database combining HITRAN with measured spectral constants for transitions in the two target spectral regions. The hybrid database reduces RMS error between the simulation and the measurements by 45% for the 7204 cm-1 region and 28% for the 7435 cm-1 region. At pressures above 10 atm, the breakdown of the impact approximation inherent to the Lorentzian line shape model becomes apparent in the direct absorption spectra, and measured results are in agreement with model results and trends at elevated temperatures reported in the literature. The wavelength-modulation spectra are shown to be less affected by the breakdown of the impact approximation and measurements agree well with the hybrid database predictions to higher pressures (30 atm).

Parameterization of light absorption by components of seawater in optically complex coastal waters of the Crimea Peninsula (Black Sea).

PubMed

Dmitriev, Egor V; Khomenko, Georges; Chami, Malik; Sokolov, Anton A; Churilova, Tatyana Y; Korotaev, Gennady K

2009-03-01

The absorption of sunlight by oceanic constituents significantly contributes to the spectral distribution of the water-leaving radiance. Here it is shown that current parameterizations of absorption coefficients do not apply to the optically complex waters of the Crimea Peninsula. Based on in situ measurements, parameterizations of phytoplankton, nonalgal, and total particulate absorption coefficients are proposed. Their performance is evaluated using a log-log regression combined with a low-pass filter and the nonlinear least-square method. Statistical significance of the estimated parameters is verified using the bootstrap method. The parameterizations are relevant for chlorophyll a concentrations ranging from 0.45 up to 2 mg/m(3).

The effect of water stress on super-high- density 'Koroneiki' olive oil quality.

PubMed

Dag, Arnon; Naor, Amos; Ben-Gal, Alon; Harlev, Guy; Zipori, Isaac; Schneider, Doron; Birger, Reuven; Peres, Moti; Gal, Yoni; Kerem, Zohar

2015-08-15

Over the last two decades, the area of cultivated super-high-density olive orchards has increased rapidly. Water stress is an important tool in super-high-density orchards to reduce tree growth and promote suitability for overhead mechanical harvesters. Little is known regarding the effect of water stress in super-high-density orchards on oil quality parameters. In this study the effect of irrigation rate on oil quality parameters was evaluated in a six-year-old super-high-density 'Koreneiki' olive orchard for five consecutive seasons. Five water status levels, determined by irrigating in order to maintain various midday stem water potential threshold values (-1.5, -2, -2.5, -3 and -4 MPa), were applied during the oil accumulation stage. The MUFA/PUFA ratio and free fatty acid content generally decreased as a function of increasing tree water stress. In most seasons a reduction in polyphenols was found with decreasing irrigation level. Peroxide value was not affected by the water stress level. The present study demonstrates that limiting irrigation and exposure of olive trees to water stress in a super-high-density orchard lowers free fatty acid content and therefore benefits oil quality. However, the decreased MUFA/PUFA ratio and the reduction in polyphenol content that were also found under increased water stress negatively influence oil quality. © 2014 Society of Chemical Industry.

Quasar Absorption Studies

NASA Technical Reports Server (NTRS)

Mushotzky, Richard (Technical Monitor); Elvis, Martin

2004-01-01

The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

Recrystallization and Water Absorption Properties of Vitrified Trehalose Near Room Temperature.

PubMed

Shirakashi, Ryo; Takano, Kiyoshi

2018-05-10

To provide the physicochemical properties of vitrified trehalose for predicting its recrystallization. Thin films of vitrified trehalose solutions were prepared at room temperature and exposed to various humid and temperature atmospheres. The in-situ amount of retained water in the vacuum-dried trehalose thin film during exposure was determined using its FTIR spectrum by quantifying the extremely infinitesimal amount of retained water in the trehalose solution. Recrystallization of the sample was also assessed by the FTIR spectrum of trehalose dihydrate. The effective water absorption coefficient, h meff , exponentially increased to the water activity of the trehalose sample, A w , at 25°C and 40°C at which the increasing rates are comparable. The surface energy of trehalose dihydrate, γ, was found to be lower than the value calculated from the reported equation, neglecting the effects of the activity of the solute and solvent water. The retained water in trehalose considerably increases its affinity for water vapor, and the change in this affinity with regard to the water activity is nearly independent of temperature. The dihydrate nucleation rate of trehalose-water system is maximal when trehalose weight ratio is ~0.8 at 25°C and is slightly higher (~0.85) at 40°C.

The Reverse Thermal Effect in Epoxy Resins and Moisture Absorption in Semi-Interpenetrating Polymer Networks.

NASA Astrophysics Data System (ADS)

El-Sa'Ad, Leila

1989-12-01

Available from UMI in association with The British Library. Requires signed TDF. Epoxy resins exhibit many desirable properties which make them ideal subjects for use as matrices of composite materials in many commercial, military and space applications. However, due to their high cross-link density they are often brittle. Epoxy resin networks have been modified by incorporating tough, ductile thermoplastics. Such systems are referred to as Semi-Interpenetrating Polymer Networks (Semi-IPN). Systematic modification to the thermoplastics backbone allowed the morphology of the blend to be controlled from a homogeneous one-phase structure to fully separated structures. The moisture absorption by composites in humid environments has been found to lead to a deterioration in the physical and mechanical properties of the matrix. Therefore, in order to utilize composites to their full potential, their response to hot/wet environments must be known. The aims of this investigation were two-fold. Firstly, to study the effect of varying the temperature of exposure at different stages in the absorption process on the water absorption behaviour of a TGDDM/DDS epoxy resin system. Secondly, to study water absorption characteristics, under isothermal conditions, of Semi-Interpenetrating Polymer Networks possessing different morphologies, and develop a theoretical model to evaluate the diffusion coefficients of the two-phase structures. The mathematical treatment used in this analysis was based on Fick's second law of diffusion. Tests were performed on specimens immersed in water at 10 ^circ, 40^circ and 70^circC, their absorption behaviour and swelling behaviour, as a consequence of water absorption, were investigated. The absorption results of the variable temperature absorption tests indicated a saturation dependence on the absorption behaviour. Specimens saturated at a high temperature will undergo further absorption when transferred to a lower temperature. This behaviour was

Blood Density Is Nearly Equal to Water Density: A Validation Study of the Gravimetric Method of Measuring Intraoperative Blood Loss

PubMed Central

Vitello, Dominic J.; Ripper, Richard M.; Fettiplace, Michael R.; Weinberg, Guy L.; Vitello, Joseph M.

2015-01-01

Purpose. The gravimetric method of weighing surgical sponges is used to quantify intraoperative blood loss. The dry mass minus the wet mass of the gauze equals the volume of blood lost. This method assumes that the density of blood is equivalent to water (1 gm/mL). This study's purpose was to validate the assumption that the density of blood is equivalent to water and to correlate density with hematocrit. Methods. 50 µL of whole blood was weighed from eighteen rats. A distilled water control was weighed for each blood sample. The averages of the blood and water were compared utilizing a Student's unpaired, one-tailed t-test. The masses of the blood samples and the hematocrits were compared using a linear regression. Results. The average mass of the eighteen blood samples was 0.0489 g and that of the distilled water controls was 0.0492 g. The t-test showed P = 0.2269 and R 2 = 0.03154. The hematocrit values ranged from 24% to 48%. The linear regression R 2 value was 0.1767. Conclusions. The R 2 value comparing the blood and distilled water masses suggests high correlation between the two populations. Linear regression showed the hematocrit was not proportional to the mass of the blood. The study confirmed that the measured density of blood is similar to water. PMID:26464949

Blood Density Is Nearly Equal to Water Density: A Validation Study of the Gravimetric Method of Measuring Intraoperative Blood Loss.

PubMed

Vitello, Dominic J; Ripper, Richard M; Fettiplace, Michael R; Weinberg, Guy L; Vitello, Joseph M

2015-01-01

Purpose. The gravimetric method of weighing surgical sponges is used to quantify intraoperative blood loss. The dry mass minus the wet mass of the gauze equals the volume of blood lost. This method assumes that the density of blood is equivalent to water (1 gm/mL). This study's purpose was to validate the assumption that the density of blood is equivalent to water and to correlate density with hematocrit. Methods. 50 µL of whole blood was weighed from eighteen rats. A distilled water control was weighed for each blood sample. The averages of the blood and water were compared utilizing a Student's unpaired, one-tailed t-test. The masses of the blood samples and the hematocrits were compared using a linear regression. Results. The average mass of the eighteen blood samples was 0.0489 g and that of the distilled water controls was 0.0492 g. The t-test showed P = 0.2269 and R (2) = 0.03154. The hematocrit values ranged from 24% to 48%. The linear regression R (2) value was 0.1767. Conclusions. The R (2) value comparing the blood and distilled water masses suggests high correlation between the two populations. Linear regression showed the hematocrit was not proportional to the mass of the blood. The study confirmed that the measured density of blood is similar to water.

Correction to the Beer-Lambert-Bouguer law for optical absorption.

PubMed

Abitan, Haim; Bohr, Henrik; Buchhave, Preben

2008-10-10

The Beer-Lambert-Bouguer absorption law, known as Beer's law for absorption in an optical medium, is precise only at power densities lower than a few kW. At higher power densities this law fails because it neglects the processes of stimulated emission and spontaneous emission. In previous models that considered those processes, an analytical expression for the absorption law could not be obtained. We show here that by utilizing the Lambert W-function, the two-level energy rate equation model is solved analytically, and this leads into a general absorption law that is exact because it accounts for absorption as well as stimulated and spontaneous emission. The general absorption law reduces to Beer's law at low power densities. A criterion for its application is given along with experimental examples. (c) 2008 Optical Society of America

Reduced vertebral bone density in hypercalciuric nephrolithiasis

NASA Technical Reports Server (NTRS)

Pietschmann, F.; Breslau, N. A.; Pak, C. Y.

1992-01-01

Dual-energy x-ray absorptiometry and single-photon absorptiometry were used to determine bone density at the lumbar spine and radial shaft in 62 patients with absorptive hypercalciuria, 27 patients with fasting hypercalciuria, and 31 nonhypercalciuric stone formers. Lumbar bone density was significantly lower in patients with absorptive (-10%) as well as in those with fasting hypercalciuria (-12%), with 74 and 92% of patients displaying values below the normal mean, whereas only 48% of the nonhypercalciuric stone formers had bone density values below the normal mean. In contrast, radial bone density was similar in all three groups of renal stone formers investigated. The comparison of urinary chemistry in patients with absorptive hypercalciuria and low normal bone density compared to those with high normal bone density showed a significantly increased 24 h urinary calcium excretion on random diet and a trend toward a higher 24 h urinary uric acid excretion and a higher body mass index in patients with low normal bone density. Moreover, among the patients with absorptive hypercalciuria we found a statistically significant correlation between the spinal bone density and the 24 h sodium and sulfate excretion and the urinary pH. These results gave evidence for an additional role of environmental factors (sodium and animal proteins) in the pathogenesis of bone loss in absorptive hypercalciuria. In conclusion, our data suggest an osteopenia of trabecular-rich bone tissues in patients with fasting and absorptive hypercalciurias.

Pressure effects on collective density fluctuations in water and protein solutions

PubMed Central

Russo, Daniela; Laloni, Alessio; Filabozzi, Alessandra; Heyden, Matthias

2017-01-01

Neutron Brillouin scattering and molecular dynamics simulations have been used to investigate protein hydration water density fluctuations as a function of pressure. Our results show significant differences between the pressure and density dependence of collective dynamics in bulk water and in concentrated protein solutions. Pressure-induced changes in the tetrahedral order of the water HB network have direct consequences for the high-frequency sound velocity and damping coefficients, which we find to be a sensitive probe for changes in the HB network structure as well as the wetting of biomolecular surfaces. PMID:29073065

First-principles X-ray absorption dose calculation for time-dependent mass and optical density.

PubMed

Berejnov, Viatcheslav; Rubinstein, Boris; Melo, Lis G A; Hitchcock, Adam P

2018-05-01

A dose integral of time-dependent X-ray absorption under conditions of variable photon energy and changing sample mass is derived from first principles starting with the Beer-Lambert (BL) absorption model. For a given photon energy the BL dose integral D(e, t) reduces to the product of an effective time integral T(t) and a dose rate R(e). Two approximations of the time-dependent optical density, i.e. exponential A(t) = c + aexp(-bt) for first-order kinetics and hyperbolic A(t) = c + a/(b + t) for second-order kinetics, were considered for BL dose evaluation. For both models three methods of evaluating the effective time integral are considered: analytical integration, approximation by a function, and calculation of the asymptotic behaviour at large times. Data for poly(methyl methacrylate) and perfluorosulfonic acid polymers measured by scanning transmission soft X-ray microscopy were used to test the BL dose calculation. It was found that a previous method to calculate time-dependent dose underestimates the dose in mass loss situations, depending on the applied exposure time. All these methods here show that the BL dose is proportional to the exposure time D(e, t) ≃ K(e)t.

Impact of Chromophoric dissolved organic matter on light absorption in lake water on the Tibetan Plateau, China

NASA Astrophysics Data System (ADS)

Nima, Ciren; Hamre, Børge; Frette, Øyvind; Erga, Svein Rune; Chen, Yi-Chun; Zhao, Lu; Sørensen, Kai; Norli, Marit; Stamnes, Jakob J.

2017-02-01

Ground-based measurements of optical properties are rare for water in lakes on the Tibetan Plateau (TP). We analyzed the spectral absorption of Chromophoric Dissolved Organic Matter (CDOM) for water samples from Lake Namtso (LN) on the TP. The mean value of the spectral slope S280-500 for CDOM absorption was found to be 0.036 nm-1, whereas the corresponding mean value for S350-500 was found to be 0.015 nm-1, implying that when comparing spectral slope values with published values, the wavelength range used for deriving them should be considered.

Absorption cooling sources atmospheric emissions decrease by implementation of simple algorithm for limiting temperature of cooling water

NASA Astrophysics Data System (ADS)

Wojdyga, Krzysztof; Malicki, Marcin

2017-11-01

Constant strive to improve the energy efficiency forces carrying out activities aimed at reduction of energy consumption hence decreasing amount of contamination emissions to atmosphere. Cooling demand, both for air-conditioning and process cooling, plays an increasingly important role in the balance of Polish electricity generation and distribution system in summer. During recent years' demand for electricity during summer months has been steadily and significantly increasing leading to deficits of energy availability during particularly hot periods. This causes growing importance and interest in trigeneration power generation sources and heat recovery systems producing chilled water. Key component of such system is thermally driven chiller, mostly absorption, based on lithium-bromide and water mixture. Absorption cooling systems also exist in Poland as stand-alone systems, supplied with heating from various sources, generated solely for them or recovered as waste or useless energy. The publication presents a simple algorithm, designed to reduce the amount of heat for the supply of absorption chillers producing chilled water for the purposes of air conditioning by reducing the temperature of the cooling water, and its impact on decreasing emissions of harmful substances into the atmosphere. Scale of environmental advantages has been rated for specific sources what enabled evaluation and estimation of simple algorithm implementation to sources existing nationally.

Quasi-static energy absorption of hollow microlattice structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, YL; Schaedler, TA; Jacobsen, AJ

2014-12-01

We present a comprehensive modeling and numerical study focusing on the energy quasi-static crushing behavior and energy absorption characteristics of hollow tube microlattice structures. The peak stress and effective plateau stress of the hollow microlattice structures are deduced for different geometrical parameters which gives volume and mass densities of energy absorption, D-v and D-m, scale with the relative density, (rho) over bar, as D-v similar to (rho) over bar (1) (5) and D-m similar to (rho) over bar (0 5), respectively, fitting very well to the experimental results of both 60 degrees inclined and 90 degrees predominately microlattices. Then themore » strategies for energy absorption enhancement are proposed for the engineering design of microlattice structures. By introducing a gradient in the thickness or radius of the lattice members, the buckle propagation can be modulated resulting in an increase in energy absorption density that can exceed 40%. Liquid filler is another approach to improve energy absorption by strengthening the microtruss via circumference expansion, and the gain may be over 100% in terms of volume density. Insight into the correlations between microlattice architecture and energy absorption performance combined with the high degree of architecture control paves the way for designing high performance microlattice structures for a range of impact and impulse mitigation applications for vehicles and structures. (C) 2014 Elsevier Ltd. All rights reserved.« less

Density profile of water confined in cylindrical pores in MCM-41 silica.

PubMed

Soper, Alan K

2012-02-15

Recently, water absorbed in the porous silica material MCM-41-S15 has been used to demonstrate an apparent fragile to strong dynamical crossover on cooling below ∼220 K, and also to claim that the density of confined water reaches a minimum at a temperature around 200 K. Both of these behaviours are purported to arise from the crossing of a Widom line above a conjectured liquid-liquid critical point in bulk water. Here it is shown that traditional estimates of the pore diameter in this porous silica material (of order 15 Å) are too small to allow the amount of water that is observed to be absorbed by these materials (around 0.5 g H(2)O/g substrate) to be absorbed only inside the pore. Either the additional water is absorbed on the surface of the silica particles and outside the pores, or else the pores are larger than the traditional estimates. In addition the low Q Bragg intensities from a sample of MCM-41-S15 porous silica under different dry and wet conditions and with different hydrogen isotopes are simulated using a simple model of the water and silica density profile across the pore. It is found the best agreement of these intensities with experimental data is shown by assuming the much larger pore diameter of 25 Å (radius 12.5 Å). Qualitative agreement is found between these simulated density profiles and those found in recent empirical potential structure refinement simulations of the same data, even though the latter data did not specifically include the Bragg peaks in the structure refinement. It is shown that the change in the (100) peak intensity on cooling from 300 to 210 K, which previously has been ascribed to a change in density of the confined water on cooling, can equally be ascribed to a change in density profile at constant average density. It is further pointed out that, independent of whether the pore diameter really is as large as 25 Å or whether a significant amount of water is absorbed outside the pore, the earlier reports of a

Simulation of X-ray absorption spectra with orthogonality constrained density functional theory.

PubMed

Derricotte, Wallace D; Evangelista, Francesco A

2015-06-14

Orthogonality constrained density functional theory (OCDFT) [F. A. Evangelista, P. Shushkov and J. C. Tully, J. Phys. Chem. A, 2013, 117, 7378] is a variational time-independent approach for the computation of electronic excited states. In this work we extend OCDFT to compute core-excited states and generalize the original formalism to determine multiple excited states. Benchmark computations on a set of 13 small molecules and 40 excited states show that unshifted OCDFT/B3LYP excitation energies have a mean absolute error of 1.0 eV. Contrary to time-dependent DFT, OCDFT excitation energies for first- and second-row elements are computed with near-uniform accuracy. OCDFT core excitation energies are insensitive to the choice of the functional and the amount of Hartree-Fock exchange. We show that OCDFT is a powerful tool for the assignment of X-ray absorption spectra of large molecules by simulating the gas-phase near-edge spectrum of adenine and thymine.

Solution Structures of Highly Active Molecular Ir Water-Oxidation Catalysts from Density Functional Theory Combined with High-Energy X-ray Scattering and EXAFS Spectroscopy.

PubMed

Yang, Ke R; Matula, Adam J; Kwon, Gihan; Hong, Jiyun; Sheehan, Stafford W; Thomsen, Julianne M; Brudvig, Gary W; Crabtree, Robert H; Tiede, David M; Chen, Lin X; Batista, Victor S

2016-05-04

The solution structures of highly active Ir water-oxidation catalysts are elucidated by combining density functional theory, high-energy X-ray scattering (HEXS), and extended X-ray absorption fine structure (EXAFS) spectroscopy. We find that the catalysts are Ir dimers with mono-μ-O cores and terminal anionic ligands, generated in situ through partial oxidation of a common catalyst precursor. The proposed structures are supported by (1)H and (17)O NMR, EPR, resonance Raman and UV-vis spectra, electrophoresis, etc. Our findings are particularly valuable to understand the mechanism of water oxidation by highly reactive Ir catalysts. Importantly, our DFT-EXAFS-HEXS methodology provides a new in situ technique for characterization of active species in catalytic systems.

Water absorption and method improvement concerning electrical conductivity testing Acacia mangium (Fabaceae) seeds.

PubMed

de Oliveira, Daniel Luiz; Smiderle, Oscar Jose; Paulino, Pollyana Priscila Schuertz; Souza, Aline das Graças

2016-12-01

Acacia is an important forest species of rapid growth whose seeds have tegument dormancy. In this work it was intended to characterize water absorption pattern after seed dormancy break, and to determine the amount of water, container size and the need of breaking the tegument dormancy, as to perform electrical conductivity test in small and large seeds of Acacia mangium (Fabaceae). The seeds were collected from 10, 8 and 6 years old trees established in poor yielding-capacity soils on savannah areas of Roraima, Brazil; seeds were classified in six lots concerning to seed size and tree age. Germination tests (50 seeds and four replications per lot) were carried out on germitest® paper maintained on gerbox at 25 °C. Imbibition was verified by seed weighing at different times (0, 2, 5, 8, 12, 16, 24, 36, 48, 60, 72, 84, 96 and 120 hours). The electrical conductivity test consisted of three experiments, distinguished by the amount of water used and by the container size in which seeds were immersed. Seeds of A. mangium coming from 10 years old trees presented increased germination percent and germination speed than seeds of six-year old trees. Small seeds presented increased in electrical conductivity and water absorption until 120 hours when compared to large seeds. The immersion of seeds of A. mangium in 40 mL of distilled water into 180 mL plastic containers, after dormancy break, it is indicated for the determination of electrical conductivity test. The ratio of electrolytes by seed mass, after 24 hours of immersion in water, turns electrical conductivity test more accurate concerning A. mangium seeds.

Phytoplankton absorption predicts patterns in primary productivity in Australian coastal shelf waters

NASA Astrophysics Data System (ADS)

Robinson, C. M.; Cherukuru, N.; Hardman-Mountford, N. J.; Everett, J. D.; McLaughlin, M. J.; Davies, K. P.; Van Dongen-Vogels, V.; Ralph, P. J.; Doblin, M. A.

2017-06-01

The phytoplankton absorption coefficient (aPHY) has been suggested as a suitable alternate first order predictor of net primary productivity (NPP). We compiled a dataset of surface bio-optical properties and phytoplankton NPP measurements in coastal waters around Australia to examine the utility of an in-situ absorption model to estimate NPP. The magnitude of surface NPP (0.20-19.3 mmol C m-3 d-1) across sites was largely driven by phytoplankton biomass, with higher rates being attributed to the microplankton (>20 μm) size class. The phytoplankton absorption coefficient aPHY for PAR (photosynthetically active radiation; āPHY)) ranged from 0.003 to 0.073 m-1, influenced by changes in phytoplankton community composition, physiology and environmental conditions. The aPHY coefficient also reflected changes in NPP and the absorption model-derived NPP could explain 73% of the variability in measured surface NPP (n = 41; RMSE = 2.49). The absorption model was applied to two contrasting coastal locations to examine NPP dynamics: a high chlorophyll-high variation (HCHV; Port Hacking National Reference Station) and moderate chlorophyll-low variation (MCLV; Yongala National Reference Station) location in eastern Australia using the GIOP-DC satellite aPHY product. Mean daily NPP rates between 2003 and 2015 were higher at the HCHV site (1.71 ± 0.03 mmol C m-3 d-1) with the annual maximum NPP occurring during the austral winter. In contrast, the MCLV site annual NPP peak occurred during the austral wet season and had lower mean daily NPP (1.43 ± 0.03 mmol C m-3 d-1) across the time-series. An absorption-based model to estimate NPP is a promising approach for exploring the spatio-temporal dynamics in phytoplankton NPP around the Australian continental shelf.

Photoionization-driven Absorption-line Variability in Balmer Absorption Line Quasar LBQS 1206+1052

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Luming; Zhou, Hongyan; Ji, Tuo

In this paper we present an analysis of absorption-line variability in mini-BAL quasar LBQS 1206+1052. The Sloan Digital Sky Survey spectrum demonstrates that the absorption troughs can be divided into two components of blueshift velocities of ∼700 and ∼1400 km s{sup −1} relative to the quasar rest frame. The former component shows rare Balmer absorption, which is an indicator of high-density absorbing gas; thus, the quasar is worth follow-up spectroscopic observations. Our follow-up optical and near-infrared spectra using MMT, YFOSC, TSpec, and DBSP reveal that the strengths of the absorption lines vary for both components, while the velocities do notmore » change. We reproduce all of the spectral data by assuming that only the ionization state of the absorbing gas is variable and that all other physical properties are invariable. The variation of ionization is consistent with the variation of optical continuum from the V -band light curve. Additionally, we cannot interpret the data by assuming that the variability is due to a movement of the absorbing gas. Therefore, our analysis strongly indicates that the absorption-line variability in LBQS 1206+1052 is photoionization driven. As shown from photoionization simulations, the absorbing gas with blueshift velocity of ∼700 km s{sup −1} has a density in the range of 10{sup 9} to 10{sup 10} cm{sup −3} and a distance of ∼1 pc, and the gas with blueshift velocity of ∼1400 km s{sup −1} has a density of 10{sup 3} cm{sup −3} and a distance of ∼1 kpc.« less

Absorption and resonance Raman study of the pyromellitic diahydride anion via density functional theory

NASA Astrophysics Data System (ADS)

Andruniow, T.; Pawlikowski, M.

2000-05-01

The electronic structure of the low-energy states of the pyromellitic diahydride (PMDA) anion is investigated in terms of the VWN (Vosco-Wilk-Nusair) the BP (Becke-Perdew) and the B3LYP density functional (DF) methods employed with 6-31G * basis sets. All the methods are shown to reproduce correctly the absorption and resonance Raman spectra in the region corresponding to the low-energy 1 2Au→1 2B3g transition. The discrepancies between the theory and experiment are attributed to a (weak) Dushinsky effect predominately due to a mixing of the ν3=1593 cm -1 and ν4=1342 cm -1 vibrations in the 1 2B3 g state of the PMDA radical.

Viscosity and density of methanol/water mixtures at low temperatures

NASA Technical Reports Server (NTRS)

Austin, J. G.; Kurata, F.; Swift, G. W.

1968-01-01

Viscosity and density are measured at low temperatures for three methanol/water mixtures. Viscosity is determined by a modified falling cylinder method or a calibrated viscometer. Density is determined by the volume of each mixture contained in a calibrated glass cell placed in a constant-temperature bath.

Simulating pump-probe photoelectron and absorption spectroscopy on the attosecond timescale with time-dependent density functional theory.

PubMed

De Giovannini, Umberto; Brunetto, Gustavo; Castro, Alberto; Walkenhorst, Jessica; Rubio, Angel

2013-05-10

Molecular absorption and photoelectron spectra can be efficiently predicted with real-time time-dependent density functional theory. We show herein how these techniques can be easily extended to study time-resolved pump-probe experiments, in which a system response (absorption or electron emission) to a probe pulse is measured in an excited state. This simulation tool helps with the interpretation of fast-evolving attosecond time-resolved spectroscopic experiments, in which electronic motion must be followed at its natural timescale. We show how the extra degrees of freedom (pump-pulse duration, intensity, frequency, and time delay), which are absent in a conventional steady-state experiment, provide additional information about electronic structure and dynamics that improve characterization of a system. As an extension of this approach, time-dependent 2D spectroscopy can also be simulated, in principle, for large-scale structures and extended systems. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of water pH using absorption-based optical sensors: evaluation of different calculation methods

NASA Astrophysics Data System (ADS)

Wang, Hongliang; Liu, Baohua; Ding, Zhongjun; Wang, Xiangxin

2017-02-01

Absorption-based optical sensors have been developed for the determination of water pH. In this paper, based on the preparation of a transparent sol-gel thin film with a phenol red (PR) indicator, several calculation methods, including simple linear regression analysis, quadratic regression analysis and dual-wavelength absorbance ratio analysis, were used to calculate water pH. Results of MSSRR show that dual-wavelength absorbance ratio analysis can improve the calculation accuracy of water pH in long-term measurement.

A study of electron density profiles in relation to ionization sources and ground-based radio wave absorption measurements, part 2

NASA Technical Reports Server (NTRS)

Gnanalingam, S.; Kane, J. A.

1975-01-01

The D-region ion production functions are used to calculate the relationship between radio wave absorption and the flux level of X-rays in the 1-8A wavelength band. In order to bring this calculation into agreement with the empirically established relationship, it was found necessary to reduce by, a factor of about 5, the Meira nitric oxide densities below 90 km.

Absorption and retention of nickel from drinking water in relation to food intake and nickel sensitivity.

PubMed

Nielsen, G D; Søderberg, U; Jørgensen, P J; Templeton, D M; Rasmussen, S N; Andersen, K E; Grandjean, P

1999-01-01

Two studies were performed to examine the influence of fasting and food intake on the absorption and retention of nickel added to drinking water and to determine if nickel sensitization played any role in this regard. First, eight nonallergic male volunteers fasted overnight before being given nickel in drinking water (12 micrograms Ni/kg) and, at different time intervals, standardized 1400-kJ portions of scrambled eggs. When nickel was ingested in water 30 min or 1 h prior to the meal, peak nickel concentrations in serum occurred 1 h after the water intake, and the peak was 13-fold higher than the one seen 1 h after simultaneous intake of nickel-containing water and scrambled eggs. In the latter case, a smaller, delayed peak occurred 3 h after the meal. Median urinary nickel excretion half-times varied between 19.9 and 26.7 h. Within 3 days, the amount of nickel excreted corresponded to 2.5% of the nickel ingested when it was mixed into the scrambled eggs. Increasing amounts were excreted as the interval between the water and the meal increased, with 25.8% of the administered dose being excreted when the eggs were served 4 h prior to the nickel-containing drinking water. In the second experiment, a stable nickel isotope, 61Ni, was given in drinking water to 20 nickel-sensitized women and 20 age-matched controls, both groups having vesicular hand eczema of the pompholyx type. Nine of 20 nickel allergic eczema patients experienced aggravation of hand eczema after nickel administration, and three also developed a maculopapular exanthema. No exacerbation was seen in the control group. The course of nickel absorption and excretion in the allergic groups did not differ and was similar to the pattern seen in the first study, although the absorption in the women was less. A sex-related difference in gastric emptying rates may play a role. Thus, food intake and gastric emptying are of substantial significance for the bioavailability of nickel from aqueous solutions

Mapping Surface Water DOC in the Northern Gulf of Mexico Using CDOM Absorption Coefficients and Remote Sensing Imagery

NASA Astrophysics Data System (ADS)

Kelly, B.; Chelsky, A.; Bulygina, E.; Roberts, B. J.

2017-12-01

Remote sensing techniques have become valuable tools to researchers, providing the capability to measure and visualize important parameters without the need for time or resource intensive sampling trips. Relationships between dissolved organic carbon (DOC), colored dissolved organic matter (CDOM) and spectral data have been used to remotely sense DOC concentrations in riverine systems, however, this approach has not been applied to the northern Gulf of Mexico (GoM) and needs to be tested to determine how accurate these relationships are in riverine-dominated shelf systems. In April, July, and October 2017 we sampled surface water from 80+ sites over an area of 100,000 km2 along the Louisiana-Texas shelf in the northern GoM. DOC concentrations were measured on filtered water samples using a Shimadzu TOC-VCSH analyzer using standard techniques. Additionally, DOC concentrations were estimated from CDOM absorption coefficients of filtered water samples on a UV-Vis spectrophotometer using a modification of the methods of Fichot and Benner (2011). These values were regressed against Landsat visible band spectral data for those same locations to establish a relationship between the spectral data, CDOM absorption coefficients. This allowed us to spatially map CDOM absorption coefficients in the Gulf of Mexico using the Landsat spectral data in GIS. We then used a multiple linear regressions model to derive DOC concentrations from the CDOM absorption coefficients and applied those to our map. This study provides an evaluation of the viability of scaling up CDOM absorption coefficient and remote-sensing derived estimates of DOC concentrations to the scale of the LA-TX shelf ecosystem.

Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

NASA Astrophysics Data System (ADS)

Anheier, N. C., Jr.; McDonald, C. E.; Cuta, J. M.; Cuta, F. M.; Olsen, K. B.

1995-05-01

This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. Pacific Northwest Laboratory (PNL) researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH4(+)). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

Water Uptake Vs. Density and Conversion in Silicon Containing Cyanate Esters (Briefing Charts)

DTIC Science & Technology

2014-12-17

known that cyanate ester networks decrease in density as conversion increases, and that moisture uptake increases as conversion increases at...Charts 3. DATES COVERED (From - To) Dec 2014- Dec 2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER In-House Water Uptake Vs. Density and...Polymers and Composites, San Diego, CA, 15 December, 2014. PA#14581 14. ABSTRACT A study was conducted which explored the density, percent water uptake by

Application of Time-Dependent Density Functional and Natural Bond Orbital Theories to the UV-vis Absorption Spectra of Some Phenolic Compounds.

PubMed

Marković, Svetlana; Tošović, Jelena

2015-09-03

The UV-vis properties of 22 natural phenolic compounds, comprising anthraquinones, neoflavonoids, and flavonoids were systematically examined. The time-dependent density functional theory (TDDFT) approach in combination with the B3LYP, B3LYP-D2, B3P86, and M06-2X functionals was used to simulate the UV-vis spectra of the investigated compounds. It was shown that all methods exhibit very good (B3LYP slightly better) performance in reproducing the examined UV-vis spectra. However, the shapes of the Kohn-Sham molecular orbitals (MOs) involved in electronic transitions were misleading in constructing the MO correlation diagrams. To provide better understanding of redistribution of electron density upon excitation, the natural bond orbital (NBO) analysis was applied. Bearing in mind the spatial and energetic separations, as well as the character of the π bonding, lone pair, and π* antibonding natural localized molecular orbitals (NLMOs), the "NLMO clusters" were constructed. NLMO cluster should be understood as a part of a molecule characterized with distinguished electron density. It was shown that all absorption bands including all electronic transitions need to be inspected to fully understand the UV-vis spectrum of a certain compound, and, thus, to learn more about its UV-vis light absorption. Our investigation showed that the TDDFT and NBO theories are complementary, as the results from the two approaches can be combined to interpret the UV-vis spectra. Agreement between the predictions of the TDDFT approach and those based on the NLMO clusters is excellent in the case of major electronic transitions and long wavelengths. It should be emphasized that the approach for investigation of UV-vis light absorption based on the NLMO clusters is applied for the first time.

Solvation structure of the halides from x-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antalek, Matthew; Hedman, Britt; Sarangi, Ritimukta, E-mail: ritis@slac.stanford.edu

2016-07-28

Three-dimensional models for the aqueous solvation structures of chloride, bromide, and iodide are reported. K-edge extended X-ray absorption fine structure (EXAFS) and Minuit X-ray absorption near edge (MXAN) analyses found well-defined single shell solvation spheres for bromide and iodide. However, dissolved chloride proved structurally distinct, with two solvation shells needed to explain its strikingly different X-ray absorption near edge structure (XANES) spectrum. Final solvation models were as follows: iodide, 8 water molecules at 3.60 ± 0.13 Å and bromide, 8 water molecules at 3.40 ± 0.14 Å, while chloride solvation included 7 water molecules at 3.15 ± 0.10 Å, andmore » a second shell of 7 water molecules at 4.14 ± 0.30 Å. Each of the three derived solvation shells is approximately uniformly disposed about the halides, with no global asymmetry. Time-dependent density functional theory calculations simulating the chloride XANES spectra following from alternative solvation spheres revealed surprising sensitivity of the electronic state to 6-, 7-, or 8-coordination, implying a strongly bounded phase space for the correct structure during an MXAN fit. MXAN analysis further showed that the asymmetric solvation predicted from molecular dynamics simulations using halide polarization can play no significant part in bulk solvation. Classical molecular dynamics used to explore chloride solvation found a 7-water solvation shell at 3.12 (−0.04/+0.3) Å, supporting the experimental result. These experiments provide the first fully three-dimensional structures presenting to atomic resolution the aqueous solvation spheres of the larger halide ions.« less

Disposition of lipid-based formulation in the intestinal tract affects the absorption of poorly water-soluble drugs.

PubMed

Iwanaga, Kazunori; Kushibiki, Toshihiro; Miyazaki, Makoto; Kakemi, Masawo

2006-03-01

Solvent Green 3 (SG), a model poorly water-soluble compound, was orally administered to rats with soybean oil emulsion or the Self-microemulsifying drug delivery system (SMEDDS) composed of Gelucire44/14. The bioavailability of SG after oral administration with SMEDDS was 1.7-fold higher than that with soybean oil emulsion. The intestinal absorption of lipid-based formulations themselves was evaluated by the in situ closed loop method. The effect of lipase and bile salt on their absorption was also evaluated. SMEDDS itself was rapidly absorbed in the intestine even in the absence of lipase and bile salt, and the absorption was increased by the addition of lipase and bile salt. On the other hand, no soybean oil emulsion was absorbed in the absence of lipase and bile salt. However, mixed micelle prepared from emulsion by incubating soybean oil emulsion with lipase and bile salt was rapidly absorbed through the intestine. Without lipase and bile salt, SG was not absorbed after administration with soybean oil emulsion. Therefore, we concluded that the degradation of soybean oil emulsion was needed for SG to be absorbed through the intestine. Furthermore, we investigated the intestinal absorption of SG after oral administration to rats whose chylomicron synthesis were inhibited by pretreatment with colchicine. Colchicine completely inhibited the intestinal absorption of SG after administration with each lipid-based formulation, suggesting that SG was absorbed from the intestine via a lymphatic route. Absorption of the dosage formulation should be paid attention when poorly water-soluble drugs are orally administered with lipid-based formulation.

Ab Initio Modeling of the Electronic Absorption Spectrum of Previtamin D in Solution

NASA Astrophysics Data System (ADS)

Zhu, Tianyang

To study the solvent effects of water on the previtamin D absorption spectrum, we use the quantum mechanics (QM)/molecular mechanics (MM) method combined with replica-exchange molecular dynamics (REMD). The QM method is applied for the previtamin D molecule and the MM method is used for the water molecules. To enhance conformational sampling of the flexible previtamin D molecule we apply REMD. Based on the REMD structures, we calculate the macroscopic ensemble of the absorption spectrum in solution by time-dependent density functional theory (TDDFT). Comparison between the calculated spectrum in the gas phase and in the solution reveals minor influences of the solvent on the absorption spectrum. In the conventional molecule dynamics simulation, the previtamin D molecule can be trapped by local minimum and cannot overcome energetics barriers when it is calculated at the room temperature. In addition, the higher temperature calculation for the molecule in REMD allows to overcome energetics barriers and to change the structure to other rotational isomers, then switch to the lower temperature and gives a more complete result in the configuration space for the lower temperature.

Temperature and salinity correction coefficients for light absorption by water in the visible to infrared spectral region.

PubMed

Röttgers, Rüdiger; McKee, David; Utschig, Christian

2014-10-20

The light absorption coefficient of water is dependent on temperature and concentration of ions, i.e. the salinity in seawater. Accurate knowledge of the water absorption coefficient, a, and/or its temperature and salinity correction coefficients, Ψ(T) and Ψ(S), respectively, is essential for a wide range of optical applications. Values are available from published data only at specific narrow wavelength ranges or at single wavelengths in the visible and infrared regions. Ψ(T) and Ψ(S) were therefore spectrophotometrically measured throughout the visible, near, and short wavelength infrared spectral region (400 to ~2700 nm). Additionally, they were derived from more precise measurements with a point-source integrating-cavity absorption meter (PSICAM) for 400 to 700 nm. When combined with earlier measurements from the literature in the range of 2600 - 14000 nm (wavenumber: 3800 - 700 cm(-1)), the coefficients are provided for 400 to 14000 nm (wavenumber: 25000 to 700 cm(-1)).

Propagation of ultrashort laser pulses in water: linear absorption and onset of nonlinear spectral transformation.

PubMed

Sokolov, Alexei V; Naveira, Lucas M; Poudel, Milan P; Strohaber, James; Trendafilova, Cynthia S; Buck, William C; Wang, Jieyu; Strycker, Benjamin D; Wang, Chao; Schuessler, Hans; Kolomenskii, Alexandre; Kattawar, George W

2010-01-20

We study propagation of short laser pulses through water and use a spectral hole filling technique to essentially perform a sensitive balanced comparison of absorption coefficients for pulses of different duration. This study is motivated by an alleged violation of the Bouguer-Lambert-Beer law at low light intensities, where the pulse propagation is expected to be linear, and by a possible observation of femtosecond optical precursors in water. We find that at low intensities, absorption of laser light is determined solely by its spectrum and does not directly depend on the pulse duration, in agreement with our earlier work and in contradiction to some work of others. However, as the laser fluence is increased, interaction of light with water becomes nonlinear, causing energy exchange among the pulse's spectral components and resulting in peak-intensity dependent (and therefore pulse-duration dependent) transmission. For 30 fs pulses at 800 nm center wavelength, we determine the onset of nonlinear propagation effects to occur at a peak value of about 0.12 mJ/cm(2) of input laser energy fluence.

Determination of traces of silver in waters by anion exchange and atomic absorption spectrophotometry

USGS Publications Warehouse

Chao, T.T.; Fishman, M. J.; Ball, J.W.

1969-01-01

A method has been developed for the accurate determination of 0.1-1 ??g of silver per liter of water. The method permits stabilization of silver in water without loss to container walls. Optimum conditions have been established for the complete recovery of silver from water with an anion-exchange column, for quantitative elution of silver from the resin, and for measurement of silver by atomic absorption spectrophotometry after chelation with ammonium pyrrolidine dithiocarbamate and extraction of the chelate with MIBK. Silver in the 1-10 ??g 1 range can be determined by extraction without pre-concentration on an ion-exchange resin. ?? 1969.

Study of Water Absorption in Raffia vinifera Fibres from Bandjoun, Cameroon

PubMed Central

Sikame Tagne, N. R.; Njeugna, E.; Fogue, M.; Drean, J.-Y.; Nzeukou, A.; Fokwa, D.

2014-01-01

The study is focused on the water diffusion phenomenon through the Raffia vinifera fibre from the stem. The knowledge on the behavior of those fibres in presence of liquid during the realization of biocomposite, is necessary. The parameters like percentage of water gain at the point of saturation, modelling of the kinetic of water absorption, and the effective diffusion coefficient were the main objectives. Along a stem of raffia, twelve zones of sampling were defined. From Fick's 2nd law of diffusion, a new model was proposed and evaluated compared to four other models at a constant temperature of 23°C. From the proposed model, the effective diffusion coefficient was deduced. The percentage of water gain was in the range of 303–662%. The proposed model fitted better to the experimental data. The estimated diffusion coefficient was evaluated during the initial phase and at the final phase. In any cross section located along the stem of Raffia vinifera, it was found that the effective diffusion coefficient increases from the periphery to the centre during the initial and final phases. PMID:24592199

Meta-Analysis of the Copper, Zinc, and Cadmium Absorption Capacities of Aquatic Plants in Heavy Metal-Polluted Water.

PubMed

Li, Jing; Yu, Haixin; Luan, Yaning

2015-11-26

The use of aquatic plants for phytoremediation is an important method for restoring polluted ecosystems. We sought to analyze the capacity of different aquatic plant species to absorb heavy metals and to summarize available relevant scientific data on this topic. We present a meta-analysis of Cu, Zn, and Cd absorption capacities of aquatic plants to provide a scientific basis for the selection of aquatic plants suitable for remediation of heavy-metal pollution. Plants from the Gramineae, Pontederiaceae, Ceratophyllaceae, Typhaceae and Haloragaceae showed relatively strong abilities to absorb these metals. The ability of a particular plant species to absorb a given metal was strongly correlated with its ability to absorb the other metals. However, the absorption abilities varied with the plant organ, with the following trend: roots > stems > leaves. The pH of the water and the life habits of aquatic plants (submerged and emerged) also affect the plant's ability to absorb elements. Acidic water aids the uptake of heavy metals by plants. The correlation observed between element concentrations in plants with different aquatic life habits suggested that the enrichment mechanism is related to the surface area of the plant exposed to water. We argue that this meta-analysis would aid the selection of aquatic plants suitable for heavy-metal absorption from polluted waters.

Densities, Viscosities and Derived Thermophysical Properties of Water-Saturated Imidazolium-Based Ionic Liquids.

PubMed

Martins, Mónia A R; Neves, Catarina M S S; Kurnia, Kiki A; Carvalho, Pedro J; Rocha, Marisa A A; Santos, Luís M N B F; Pinho, Simão P; Freire, Mara G

2016-01-15

In order to evaluate the impact of the alkyl side chain length and symmetry of the cation on the thermophysical properties of water-saturated ionic liquids (ILs), densities and viscosities as a function of temperature were measured at atmospheric pressure and in the (298.15 to 363.15) K temperature range, for systems containing two series of bis(trifluoromethylsulfonyl)imide-based compounds: the symmetric [C n C n im][NTf 2 ] (with n = 1-8 and 10) and asymmetric [C n C 1 im][NTf 2 ] (with n = 2-5, 7, 9 and 11) ILs. For water-saturated ILs, the density decreases with the increase of the alkyl side chain length while the viscosity increases with the size of the aliphatic tails. The saturation water solubility in each IL was further estimated with a reasonable agreement based on the densities of water-saturated ILs, further confirming that for the ILs investigated the volumetric mixing properties of ILs and water follow a near ideal behaviour. The water-saturated symmetric ILs generally present lower densities and viscosities than their asymmetric counterparts. From the experimental data, the isobaric thermal expansion coefficient and energy barrier were also estimated. A close correlation between the difference in the energy barrier values between the water-saturated and pure ILs and the water content in each IL was found, supporting that the decrease in the viscosity of ILs in presence of water is directly related with the decrease of the energy barrier.

A Water Vapor Differential Absorption LIDAR Design for Unpiloted Aerial Vehicles

NASA Technical Reports Server (NTRS)

DeYoung, Russell J.; Mead, Patricia F.

2004-01-01

This system study proposes the deployment of a water vapor Differential Absorption LIDAR (DIAL) system on an Altair unmanned aerial vehicle (UAV) platform. The Altair offers improved payload weight and volume performance, and longer total flight time as compared to other commercial UAV's. This study has generated a preliminary design for an Altair based water vapor DIAL system. The design includes a proposed DIAL schematic, a review of mechanical challenges such as temperature and humidity stresses on UAV deployed DIAL systems, an assessment of the available capacity for additional instrumentation (based on the proposed design), and an overview of possible weight and volume improvements associated with the use of customized electronic and computer hardware, and through the integration of advanced fiber-optic and laser products. The results of the study show that less than 17% of the available weight, less than 19% of the volume capacity, and approximately 11% of the electrical capacity is utilized by the proposed water vapor DIAL system on the Altair UAV.

Natural convection heat transfer in water near its density maximum

NASA Astrophysics Data System (ADS)

Yen, Yin-Chao

1990-12-01

This monograph reviews and summarizes to date the experimental and analytical results on the effect of water density near its maximum convection, transient flow and temperature structure characteristics: (1) in a vertical enclosure; (2) in a vertical annulus; (3) between horizontal concentric cylinders; (4) in a square enclosure; (5) in a rectangular enclosure; (6) in a horizontal layer; (7) in a circular confined melt layer; and (8) in bulk water during melting. In a layer of water containing a maximum density temperature of 4 C, the onset of convection (the critical number) is found not to be a constant value as in the classical normal fluid but one that varies with the imposed thermal and hydrodynamic boundaries. In horizontal layers, a nearly constant temperature zone forms and continuously expands between the warm and cold boundaries. A minimum heat transfer exists in most of the geometries studied and, in most cases, can be expressed in terms of a density distribution parameter. The effect of this parameter on a cells formation, disappearance and transient structure is discussed, and the effect of split boundary flow on heat transfer is presented.

UV spectral shift of benzene in sub- and supercritical water

NASA Astrophysics Data System (ADS)

Kometani, Noritsugu; Takemiya, Koji; Yonezawa, Yoshiro; Amita, Fujitsugu; Kajimoto, Okitsugu

2004-08-01

UV absorption spectra of benzene have been measured over the wide range of temperature and pressure from the ambient state to the supercritical state ( T = 400 °C and P = 40 MPa). The analysis of the spectral shift of benzene in water relative to that in the gas indicates that at T = 380 and 390 °C the local solvent density around benzene is likely to be depressed below the bulk density for densities near the critical density. It is found that π-hydrogen bond between benzene and water becomes evident with lowering temperature below T = 340 °C.

Novel Molecular Spectroscopic Multimethod Approach for Monitoring Water Absorption/Desorption Kinetics of CAD/CAM Poly(Methyl Methacrylate) Prosthodontics.

PubMed

Wiedemair, Verena; Mayr, Sophia; Wimmer, Daniel S; Köck, Eva Maria; Penner, Simon; Kerstan, Andreas; Steinmassl, Patricia-Anca; Dumfahrt, Herbert; Huck, Christian W

2017-07-01

Water absorbed to poly(methyl methacrylate) (PMMA)-based CAD/CAM (computer-assisted design/computer-assisted manufacturing) prosthodontics can alter their properties including hardness and stability. In the present contribution, water absorption and desorption kinetics under defined experimental conditions were monitored employing several supplementary and advanced Fourier transform infrared (FT-IR) spectroscopic techniques in combination with multivariate analysis (MVA). In this synergistic vibrational spectroscopic multimethod approach, first a novel near-infrared (NIR) diffuse fiber optic probe reflection spectroscopic method was established for time-resolved analysis of water uptake within seven days under controlled conditions. Near-infrared water absorbance spectra in a wavenumber range between 5288-5100 cm -1 (combination band) and 5424-5352 cm -1 (second overtone) were used establishing corresponding calibration and validation models to quantify the amount of water in the milligram range. Therefore, 14 well-defined samples exposed to prior optimized experimental conditions were taken into consideration. The average daily water uptake conducting reference analysis was calculated as 22 mg/day for one week. Additionally, in this study for the first time NIR two-dimensional correlation spectroscopy (2D-COS) was conducted to monitor and interpret the spectral dynamics of water absorption on the prosthodontics in a wavenumber range of 5100-5300 cm -1 . For sensitive time-resolved recording of water desorption, a recently developed high-temperature, high-pressure FT-IR reaction cell with water-free ultra-dry in situ and operando operation was applied. The reaction cell, as well as the sample holder, was fully made of quartz glass, with no hot metal or ceramic parts in the vicinity of the high temperature zone. Applying a temperature gradient in the range of 25-150 ℃, mid-infrared (MIR) 2D-COS was successfully conducted to get insights into the dynamic

Emission from water vapor and absorption from other gases at 5-7.5 μm in Spitzer-IRS Spectra Of Protoplanetary Disks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sargent, B. A.; Forrest, W.; Watson, Dan M.

We present spectra of 13 T Tauri stars in the Taurus-Auriga star-forming region showing emission in Spitzer Space Telescope Infrared Spectrograph 5-7.5 μm spectra from water vapor and absorption from other gases in these stars' protoplanetary disks. Seven stars' spectra show an emission feature at 6.6 μm due to the ν{sub 2} = 1-0 bending mode of water vapor, with the shape of the spectrum suggesting water vapor temperatures >500 K, though some of these spectra also show indications of an absorption band, likely from another molecule. This water vapor emission contrasts with the absorption from warm water vapor seenmore » in the spectrum of the FU Orionis star V1057 Cyg. The other 6 of the 13 stars have spectra showing a strong absorption band, peaking in strength at 5.6-5.7 μm, which for some is consistent with gaseous formaldehyde (H{sub 2}CO) and for others is consistent with gaseous formic acid (HCOOH). There are indications that some of these six stars may also have weak water vapor emission. Modeling of these stars' spectra suggests these gases are present in the inner few AU of their host disks, consistent with recent studies of infrared spectra showing gas in protoplanetary disks.« less

Comparison of absorption properties of colored dissolved organic matter in six different case 2 water bodies

NASA Astrophysics Data System (ADS)

Nima, Ciren; Frette, Øyvind; Hamre, Børge; Erga, Svein Rune; Chen, Yi-Chun; Zhao, Lu; Muyimbwa, Dennis; Ssenyonga, Taddeo; Ssebiyonga, Nicolausi; Okullo, Willy; Stamnes, Knut; Stamnes, Jakob J.

2017-02-01

Colored Dissolved Organic Matter (CDOM) is one of the main factors controlling the penetration of solar radiation in Case 2 water and affecting satellite-based estimation of ocean color. We present absorption properties of CDOM sampled in 6 water bodies including three in Norway (Røst coastal water, Samnangerfjord, Lysefjord), two in China (Bohai Sea, Lake Namtso), and one in Africa (Lake Victoria). These locations, which range from near the equator to subarctic regions, include water types from oligotrophic to eutrophic, and altitudes from sea level to 4,700 m above sea level.

Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anheier, N.C. Jr.; McDonald, C.E.; Cuta, J.M.

1995-05-01

This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose of this work was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. PNL researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation,more » sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH{sub 4}{sup +}). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.« less

Performance characteristics of single effect lithium bromide/ water absorption chiller for small data centers

NASA Astrophysics Data System (ADS)

Mysore, Abhishek Arun Babu

A medium data center consists of servers performing operations such as file sharing, collaboration and email. There are a large number of small and medium data centers across the world which consume more energy and are less efficient when compared to large data center facilities of companies such as GOOGLE, APPLE and FACEBOOK. Such companies are making their data center facilities more environmental friendly by employing renewable energy solutions such as wind and solar to power the data center or in data center cooling. This not only reduces the carbon footprint significantly but also decreases the costs incurred over a period of time. Cooling of data center play a vital role in proper functioning of the servers. It is found that cooling consumes about 50% of the total power consumed by the data center. Traditional method of cooling includes the use of mechanical compression chillers which consume lot of power and is not desirable. In order to eliminate the use of mechanical compressor chillers renewable energy resources such as solar and wind should be employed. One such technology is solar thermal cooling by means of absorption chiller which is powered by solar energy. The absorption chiller unit can be coupled with either flat plate or evacuated tube collectors in order to achieve the required inlet temperature for the generator of the absorption chiller unit. In this study a modular data center is considered having a cooling load requirement of 23kw. The performance characteristics of a single stage Lithium Bromide/ water refrigeration is presented in this study considering the cooling load of 23kw. Performance characteristics of each of the 4 heat exchangers within the unit is discussed which helps in customizing the unit according to the users' specific needs. This analysis helps in studying the importance of different properties such as the effect of inlet temperatures of hot water for generator, inlet temperatures of cooling water for absorber and

MODFLOW/MT3DMS-based simulation of variable-density ground water flow and transport

USGS Publications Warehouse

Langevin, C.D.; Guo, W.

2006-01-01

This paper presents an approach for coupling MODFLOW and MT3DMS for the simulation of variable-density ground water flow. MODFLOW routines were modified to solve a variable-density form of the ground water flow equation in which the density terms are calculated using an equation of state and the simulated MT3DMS solute concentrations. Changes to the MODFLOW and MT3DMS input files were kept to a minimum, and thus existing data files and data files created with most pre- and postprocessors can be used directly with the SEAWAT code. The approach was tested by simulating the Henry problem and two of the saltpool laboratory experiments (low- and high-density cases). For the Henry problem, the simulated results compared well with the steady-state semianalytic solution and also the transient isochlor movement as simulated by a finite-element model. For the saltpool problem, the simulated breakthrough curves compared better with the laboratory measurements for the low-density case than for the high-density case but showed good agreement with the measured salinity isosurfaces for both cases. Results from the test cases presented here indicate that the MODFLOW/MT3DMS approach provides accurate solutions for problems involving variable-density ground water flow and solute transport. ?? 2006 National Ground Water Association.

Hydrogeologic implications of increased septic-tank-soil-absorption system density, Ogden Valley, Weber County, Utah

USGS Publications Warehouse

Lowe, Mike; Miner, Michael L.; ,

1990-01-01

Ground water in Ogden Valley occurs in perched, confined, and unconfined aquifers in the valley fill to depths of 600 feet and more. The confined aquifer, which underlies only the western portion of the valley, is overlain by cleyey silt lacustrine sediments probably deposited during the Bonneville Basin's Little Valley lake cycle sometime between 90,000 and 150,000 years ago. The top of this cleyey silt confining layer is generally 25 to 60 feet below the ground surface. Unconfined conditions occur above and beyond the outer margin of the confining layer. The sediments overlying the confining layer are primarily Lake Bonneville deposits. Water samples from springs, streams, and wells around Pineview Reservoir, and from the reservoir itself, were collected and analyzed. These samples indicate that water quality in Ogden Valley is presently good. Average nitrate concentrations in the shallow unconfined aquifer increase toward the center of Ogden Valley. This trend was not observed in the confined aquifer. There is no evidence, however, of significant water-quality deterioration, even in the vicinity of Huntsville, a town that has been densely developed using septic-tank-soil-absorption systems for much of the time since it was founded in 1860.

Corrosion Problems in Absorption Chillers

ERIC Educational Resources Information Center

Stetson, Bruce

1978-01-01

Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

Isotope effects in liquid water probed by transmission mode x-ray absorption spectroscopy at the oxygen K-edge.

PubMed

Schreck, Simon; Wernet, Philippe

2016-09-14

The effects of isotope substitution in liquid water are probed by x-ray absorption spectroscopy at the O K-edge as measured in transmission mode. Confirming earlier x-ray Raman scattering experiments, the D2O spectrum is found to be blue shifted with respect to H2O, and the D2O spectrum to be less broadened. Following the earlier interpretations of UV and x-ray Raman spectra, the shift is related to the difference in ground-state zero-point energies between D2O and H2O, while the difference in broadening is related to the difference in ground-state vibrational zero-point distributions. We demonstrate that the transmission-mode measurements allow for determining the spectral shapes with unprecedented accuracy. Owing in addition to the increased spectral resolution and signal to noise ratio compared to the earlier measurements, the new data enable the stringent determination of blue shift and broadening in the O K-edge x-ray absorption spectrum of liquid water upon isotope substitution. The results are compared to UV absorption data, and it is discussed to which extent they reflect the differences in zero-point energies and vibrational zero-point distributions in the ground-states of the liquids. The influence of the shape of the final-state potential, inclusion of the Franck-Condon structure, and differences between liquid H2O and D2O resulting from different hydrogen-bond environments in the liquids are addressed. The differences between the O K-edge absorption spectra of water from our transmission-mode measurements and from the state-of-the-art x-ray Raman scattering experiments are discussed in addition. The experimentally extracted values of blue shift and broadening are proposed to serve as a test for calculations of ground-state zero-point energies and vibrational zero-point distributions in liquid H2O and D2O. This clearly motivates the need for new calculations of the O K-edge x-ray absorption spectrum of liquid water.

Embedded dielectric water "atom" array for broadband microwave absorber based on Mie resonance

NASA Astrophysics Data System (ADS)

Gogoi, Dhruba Jyoti; Bhattacharyya, Nidhi Saxena

2017-11-01

A wide band microwave absorber at X-band frequency range is demonstrated numerically and experimentally by embedding a simple rectangular structured dielectric water "atom" in flexible silicone substrate. The absorption peak of the absorber is tuned by manipulating the size of the dielectric water "atom." The frequency dispersive permittivity property of the water "atom" shows broadband absorption covering the entire X-band above 90% efficiency with varying the size of the water "atom." Mie resonance of the proposed absorber provides the desired impedance matching condition at the air-absorber interface across a wide frequency range in terms of electric and magnetic resonances. Multipole decomposition of induced current densities is used to identify the nature of observed resonances. Numerical absorptivity verifies that the designed absorber is polarization insensitive for normal incidence and can maintain an absorption bandwidth of more than 2 GHz in a wide-angle incidence. Additionally, the tunability of absorption property with temperature is shown experimentally.

A classical density-functional theory for describing water interfaces.

PubMed

Hughes, Jessica; Krebs, Eric J; Roundy, David

2013-01-14

We develop a classical density functional for water which combines the White Bear fundamental-measure theory (FMT) functional for the hard sphere fluid with attractive interactions based on the statistical associating fluid theory variable range (SAFT-VR). This functional reproduces the properties of water at both long and short length scales over a wide range of temperatures and is computationally efficient, comparable to the cost of FMT itself. We demonstrate our functional by applying it to systems composed of two hard rods, four hard rods arranged in a square, and hard spheres in water.

Mass density images from the diffraction enhanced imaging technique.

PubMed

Hasnah, M O; Parham, C; Pisano, E D; Zhong, Z; Oltulu, O; Chapman, D

2005-02-01

Conventional x-ray radiography measures the projected x-ray attenuation of an object. It requires attenuation differences to obtain contrast of embedded features. In general, the best absorption contrast is obtained at x-ray energies where the absorption is high, meaning a high absorbed dose. Diffraction-enhanced imaging (DEI) derives contrast from absorption, refraction, and extinction. The refraction angle image of DEI visualizes the spatial gradient of the projected electron density of the object. The projected electron density often correlates well with the projected mass density and projected absorption in soft-tissue imaging, yet the mass density is not an "energy"-dependent property of the object, as is the case of absorption. This simple difference can lead to imaging with less x-ray exposure or dose. In addition, the mass density image can be directly compared (i.e., a signal-to-noise comparison) with conventional radiography. We present the method of obtaining the mass density image, the results of experiments in which comparisons are made with radiography, and an application of the method to breast cancer imaging.

A far wing line shape theory and its application to the water continuum absorption in the infrared region. I

NASA Technical Reports Server (NTRS)

Ma, Q.; Tipping, R. H.

1991-01-01

The present theory for the continuous absorption that is due to the far-wing contribution of allowed lines is based on the quasistatic approximation for the far wing limit and the binary collision approximation of one absorber molecule and one bath molecule. The validity of the theory is discussed, and numerical results of the water-continuum absorption in the IR region are presented for comparison with experimental data. Good agreement is obtained for both the magnitude and temperature dependence of the absorption coefficients.

Absorption Spectra and Photoreactivity of p-Aminobenzophenone by Time-dependent Density Functional Theory

NASA Astrophysics Data System (ADS)

Cheng, Xue-mei; Huang, Yao; Ma, Jian-yi; Li, Xiang-yuan

2007-06-01

The absorption spectral properties of para-aminobenzophenone (p-ABP) were investigated in gas phase and in solution by time-dependent density functional theory. Calculations suggest that the singlet states vary greatly with the solvent polarities. In various polar solvents, including acetonitrile, methanol, ethanol, dimethyl sulfoxide, and dimethyl formamide, the excited S1 states with charge transfer character result from π → π* transitions. However, in nonpolar solvents, cyclohexane, and benzene, the S1 states are the result of n → π* transitions related to local excitation in the carbonyl group. The excited T1 states were calculated to have ππ* character in various solvents. From the variation of the calculated excited states, the band due to π → π* transition undergoes a redshift with an increase in solvent polarity, while the band due to n → π* transition undergoes a blueshift with an increase in solvent polarity. In addition, the triplet yields and the photoreactivities of p-ABP in various solvents are discussed.

Stomatal Density Influences Leaf Water and Leaf Wax D/H Values in Arabidopsis

NASA Astrophysics Data System (ADS)

Lee, H.; Feakins, S. J.; Sternberg, L. O.

2014-12-01

The hydrogen isotopic composition (δD) of plant leaf wax is a powerful tool to study the hydrology of past and present environments. The δD value of leaf waxes is known to primarily reflect the δD value of source water, modified by biological fractionations commonly summarized as the 'net or apparent' fractionation. It remains a challenge, however, to quantitatively relate the isotopic composition of the end product (wax) back to that of the precursor (water) because multiple isotope effects contributing to the net fractionation are not yet well understood. Transgenic variants have heretofore unexplored potential to isolate individual isotope effects. Here we report the first hydrogen isotopic measurements from transgenic Arabidopsis thaliana plants with calculations of leaf water enrichment, net and biosynthetic fractionation values from measured δD of plant waters and leaf wax n-alkanes. We employed transgenic Arabidopsis leaves, engineered to have different stomatal density, by differential expression of the stomatal growth hormone stomagen. Comparison of variants and wild types allow us to isolate the effects of stomatal density on leaf water and the net fractionation expressed by leaf wax biomarkers. Results show that transgenic leaves with denser pores have more enriched leaf water and leaf wax δD values than wild type and even more so than transgenic leaves with sparse stomata (difference of 10 ‰). Our findings that stomatal density controls leaf water and leaf wax δD values adds insights into the cause of variations in net fractionations between species, as well as suggesting that geological variations in stomatal density may modulate the sedimentary leaf wax δD record. In nature, stomatal density varies between species and environments, and all other factors being equal, this will contribute to variations in fractionations observed. Over geological history, lower stomatal densities occur at times of elevated pCO2; our findings predict reduced leaf

Effect of aminoalkyl methacrylate copolymer E/HCl on in vivo absorption of poorly water-soluble drug.

PubMed

Yoshida, Takatsune; Kurimoto, Ippei; Yoshihara, Keiichi; Umejima, Hiroyuki; Ito, Naoki; Watanabe, Shunsuke; Sako, Kazuhiro; Kikuchi, Akihiko

2013-11-01

This study aimed to investigate in vivo absorption of tacrolimus formulated as a solid dispersion using Eudragit E®/HCl (E-SD). E-SD is an aminoalkyl methacrylate copolymer that can be dissolved under neutral pH conditions. E-SD was used alone as a solid dispersion carrier and/or was mixed with tacrolimus primarily dispersed with hydroxypropylmethylcellulose (HPMC). Tacrolimus was formulated with E-SD at several different ratios. Formulations with tacrolimus/E-SD ratio of 1/3 showed higher in vivo absorption, compared to tacrolimus dispersed in the excipients (primarily HPMC) found in commercially available tacrolimus capsules, using a rat in situ closed loop method. Good correlation was observed between in vitro drug solubility and in vivo drug absorption. In vitro solubility tests and rat oral absorption studies of tacrolimus/HPMC solid dispersion formulations were also conducted after mixing the HPMC dispersion with several ratios of E-SD. E-SD/tacrolimus/HPMC formulations yielded high in vitro drug solubility but comparatively low in vivo absorption. Dog oral absorption studies were conducted using capsules containing a formulation of tacrolimus/E-SD at a ratio of 1/5. The E-SD formulation-containing capsule showed higher in vivo drug absorption than tacrolimus dispersed in the standard HPMC capsule. These studies report enhancement of the in vivo absorption of a poorly water-soluble drug following dispersion with E-SD when compared to formulation in HPMC.

A comparative study of sodium dodecyl sulfate and freezing/thawing treatment on wheat starch: The role of water absorption.

PubMed

Tao, Han; Wang, Pei; Zhang, Bao; Wu, Fengfeng; Jin, Zhengyu; Xu, Xueming

2016-06-05

The effect of freezing on functionality of native and sodium dodecyl sulfate (SDS)-treated wheat starches was investigated, with the aim of understanding the role of water absorption during freezing process. SDS is one of most efficient detergents to remove non-starch components (such as proteins and lipids) for starches but does not cause any apparent damage on granular structure. Slow swelling could be converted to rapid swelling by SDS washing, indicating higher water absorption. Freezing process induced slight roughness on starch granules but the non-starch components content was little affected. Combined SDS+freezing treatment significantly decreased both amylose and proteins non-starch components contents, which was accompanied with high gelatinization temperatures, melting enthalpy, and pasting viscosities. A smaller bread specific volume was obtained from SDS+freezing-treated starches while the crumb firmness significantly increased (p<0.05). SDS mainly extracted the surface components from starch granules, leading to high water absorption and making granules sensitive to the freezing treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Absorption and resonance Raman characteristics of β-carotene in water-ethanol mixtures, emulsion and hydrogel

NASA Astrophysics Data System (ADS)

Meinhardt-Wollweber, Merve; Suhr, Christian; Kniggendorf, Ann-Kathrin; Roth, Bernhard

2018-05-01

Absorption or resonance Raman scattering are often used to identify and even quantify carotenoids in situ. We studied the absorption spectra, the Raman spectra and their resonance behavior of β-carotene in different molecular environments set up as mixtures from lipid (emulsion) and non-polar (ethanol) solvents and a polar component (water) with regard to their application as references for in situ measurement. We show how both absorption profiles and resonance spectra of β-carotene strongly depend on the molecular environment. Most notably, our data suggests that the characteristic bathochromic absorption peak of J-aggregates does not contribute to carotenoid resonance conditions, and show how the Raman shift of the C=C stretching mode is dependent on both, the molecular environment and the excitation wavelength. Overall, the spectroscopic data collected here is highly relevant for the interpretation of in situ spectroscopic data in terms of carotenoid identification and quantification by resonance Raman spectroscopy as well as the preparation of reference samples. In particular, our data promotes careful consideration of appropriate molecular environment for reference samples.

Contaminant transport from point source on water surface in open channel flow with bed absorption

NASA Astrophysics Data System (ADS)

Guo, Jinlan; Wu, Xudong; Jiang, Weiquan; Chen, Guoqian

2018-06-01

Studying solute dispersion in channel flows is of significance for environmental and industrial applications. Two-dimensional concentration distribution for a most typical case of a point source release on the free water surface in a channel flow with bed absorption is presented by means of Chatwin's long-time asymptotic technique. Five basic characteristics of Taylor dispersion and vertical mean concentration distribution with skewness and kurtosis modifications are also analyzed. The results reveal that bed absorption affects both the longitudinal and vertical concentration distributions and causes the contaminant cloud to concentrate in the upper layer. Additionally, the cross-sectional concentration distribution shows an asymptotic Gaussian distribution at large time which is unaffected by the bed absorption. The vertical concentration distribution is found to be nonuniform even at large time. The obtained results are essential for practical implements with strict environmental standards.

Airborne differential absorption lidar system for measurements of atmospheric water vapor and aerosols

NASA Technical Reports Server (NTRS)

Carter, Arlen F.; Allen, Robert J.; Mayo, M. Neale; Butler, Carolyn F.; Grossman, Benoist E.; Ismail, Syed; Grant, William B.; Browell, Edward V.; Higdon, Noah S.; Mayor, Shane D.;

Absorption of polycyclic aromatic hydrocarbons by a highly absorptive polymeric medium.

PubMed

Francisco, Olga; Idowu, Ifeoluwa; Friesen, Kelsey L; McDougall, Matthew; Choi, Sara Seoin; Bolluch, Patrique; Daramola, Oluwadamilola; Johnson, Wesley; Palace, Vince; Stetefeld, Jörg; Tomy, Gregg T

2018-06-01

The efficacy of a lightly cross-linked polymeric bead to absorb polycyclic aromatic hydrocarbons (PAHs) from the surface of fresh- and salt-water in a simulated oil-spill scenario was assessed in this study. A layer of PAHs at the water surface was created by first preparing the PAHs in hexane and then carefully spiking this mixture onto the surface of water. Beads were then applied to the surface of the organic phase and the amount of hydrocarbons absorbed by the beads was examined at prescribed time intervals and at different temperatures. Absorption of PAHs into the beads was exhaustive with ∼86 ± 4% being selectively removed from the organic phase by 120 s. First order reaction rates best described the uptake kinetics and absorption rates ranged from 0.0085 (naphthalene) to 0.0325 s- 1 (dibenzo[a,h]anthracene). Absorption of PAHs into the beads was driven by molecular volume (A 3 ). Uptake rates increased markedly for PAHs with molecular volumes between 130 A 3 and 190 A 3 . Beyond this molecular volume there was no apparent change in the rate of uptake. This study shows that these polymeric beads have a high affinity for PAHs and can be used under various environmental conditions with negligible difference in absorptive efficacy. Copyright © 2018 Elsevier Ltd. All rights reserved.

Measured acoustic properties of variable and low density bulk absorbers

NASA Technical Reports Server (NTRS)

Dahl, M. D.; Rice, E. J.

1985-01-01

Experimental data were taken to determine the acoustic absorbing properties of uniform low density and layered variable density samples using a bulk absober with a perforated plate facing to hold the material in place. In the layered variable density case, the bulk absorber was packed such that the lowest density layer began at the surface of the sample and progressed to higher density layers deeper inside. The samples were placed in a rectangular duct and measurements were taken using the two microphone method. The data were used to calculate specific acoustic impedances and normal incidence absorption coefficients. Results showed that for uniform density samples the absorption coefficient at low frequencies decreased with increasing density and resonances occurred in the absorption coefficient curve at lower densities. These results were confirmed by a model for uniform density bulk absorbers. Results from layered variable density samples showed that low frequency absorption was the highest when the lowest density possible was packed in the first layer near the exposed surface. The layers of increasing density within the sample had the effect of damping the resonances.

Meta-Analysis of the Copper, Zinc, and Cadmium Absorption Capacities of Aquatic Plants in Heavy Metal-Polluted Water

PubMed Central

Li, Jing; Yu, Haixin; Luan, Yaning

2015-01-01

The use of aquatic plants for phytoremediation is an important method for restoring polluted ecosystems. We sought to analyze the capacity of different aquatic plant species to absorb heavy metals and to summarize available relevant scientific data on this topic. We present a meta-analysis of Cu, Zn, and Cd absorption capacities of aquatic plants to provide a scientific basis for the selection of aquatic plants suitable for remediation of heavy-metal pollution. Plants from the Gramineae, Pontederiaceae, Ceratophyllaceae, Typhaceae and Haloragaceae showed relatively strong abilities to absorb these metals. The ability of a particular plant species to absorb a given metal was strongly correlated with its ability to absorb the other metals. However, the absorption abilities varied with the plant organ, with the following trend: roots > stems > leaves. The pH of the water and the life habits of aquatic plants (submerged and emerged) also affect the plant’s ability to absorb elements. Acidic water aids the uptake of heavy metals by plants. The correlation observed between element concentrations in plants with different aquatic life habits suggested that the enrichment mechanism is related to the surface area of the plant exposed to water. We argue that this meta-analysis would aid the selection of aquatic plants suitable for heavy-metal absorption from polluted waters. PMID:26703632

Variance of transionospheric VLF wave power absorption

NASA Astrophysics Data System (ADS)

Tao, X.; Bortnik, J.; Friedrich, M.

2010-07-01

To investigate the effects of D-region electron-density variance on wave power absorption, we calculate the power reduction of very low frequency (VLF) waves propagating through the ionosphere with a full wave method using the standard ionospheric model IRI and in situ observational data. We first verify the classic absorption curves of Helliwell's using our full wave code. Then we show that the IRI model gives overall smaller wave absorption compared with Helliwell's. Using D-region electron densities measured by rockets during the past 60 years, we demonstrate that the power absorption of VLF waves is subject to large variance, even though Helliwell's absorption curves are within ±1 standard deviation of absorption values calculated from data. Finally, we use a subset of the rocket data that are more representative of the D region of middle- and low-latitude VLF wave transmitters and show that the average quiet time wave absorption is smaller than that of Helliwell's by up to 100 dB at 20 kHz and 60 dB at 2 kHz, which would make the model-observation discrepancy shown by previous work even larger. This result suggests that additional processes may be needed to explain the discrepancy.

Arsenic Speciation of Waters from the Aegean Region, Turkey by Hydride Generation: Atomic Absorption Spectrometry.

PubMed

Çiftçi, Tülin Deniz; Henden, Emur

2016-08-01

Arsenic in drinking water is a serious problem for human health. Since the toxicity of arsenic species As(III) and As(V) is different, it is important to determine the concentrations separately. Therefore, it is necessary to develop an accurate and sensitive method for the speciation of arsenic. It was intended with this work to determine the concentrations of arsenic species in water samples collected from Izmir, Manisa and nearby areas. A batch type hydride generation atomic absorption spectrometer was used. As(V) gave no signal under the optimal measurement conditions of As(III). A certified reference drinking water was analyzed by the method and the results showed excellent agreement with the reported values. The procedure was applied to 34 water samples. Eleven tap water, two spring water, 19 artesian well water and two thermal water samples were analyzed under the optimal conditions.

Moisture-Absorption and Water Dynamics in the Powder of Egg Albumen Peptide, Met-Pro-Asp-Ala-His-Leu.

PubMed

Yang, Shuailing; Liu, Xuye; Zhang, Mingdi; Lin, Songyi; Chen, Feng

2017-01-01

Moisture absorbed into the powder of Met-Pro-Asp-Ala-His-Leu (MPDAHL)-a novel egg albumen antioxidant peptide-profoundly affects its properties. In this study, we elucidated water dynamics in MPDAHL using DVS, DSC, and low-field 1 H NMR. Based on the DVS data, we found that MPDAHL sorption kinetics obey a parallel exponential model. DSC results indicated that both water and heating could change the microstructure of MPDAHL. The T 2 parameters of NMR reflected the different phases of moisture absorption revealed that there were 4 categories of water with different states or mobility in the MPDAHL during the moisture absorption process. The fastest fraction T 2b mainly dominated the hygroscopicity of MPDAHL and the absorbed water significantly changed the proton distribution and structure of MPDAHL. Thus, this study shows that DVS, DSC, and low-field 1 H NMR are effective methods for monitoring water mobility and distribution in synthetic peptides. It can be used to improve the quality assurance of functional peptides. © 2016 Institute of Food Technologists®.

Influence of radiation absorption by environmental water vapor on radiation transfer in wildland fires

Treesearch

David Frankman; Brent W. Webb; Bret W. Butler

2007-01-01

Thermal radiation emission from a simulated black flame surface to a fuel bed is analyzed by a ray-tracing technique, tracking emission from points along the flame to locations along the fuel bed while accounting for absorption by environmental water vapor in the intervening medium. The Spectral Line Weighted-sum-of-gray-gases approach was adopted for treating the...

Absolute ozone absorption cross section in the Huggins Chappuis minimum (350-470 nm) at 296 K

NASA Astrophysics Data System (ADS)

Axson, J. L.; Washenfelder, R. A.; Kahan, T. F.; Young, C. J.; Vaida, V.; Brown, S. S.

2011-11-01

We report the ozone absolute absorption cross section between 350-470 nm, the minimum between the Huggins and Chappuis bands, where the ozone cross section is less than 10-22 cm2. Ozone spectra were acquired using an incoherent broadband cavity enhanced absorption spectrometer, with three channels centered at 365, 405, and 455 nm. The accuracy of the measured cross section is 4-30%, with the greatest uncertainty near the minimum absorption at 375-390 nm. Previous measurements vary by more than an order of magnitude in this spectral region. The measurements reported here provide much greater spectral coverage than the most recent measurements. The effect of O3 concentration and water vapor partial pressure were investigated, however there were no observable changes in the absorption spectrum most likely due to the low optical density of the complex.

Analysis of current density and specific absorption rate in biological tissue surrounding transcutaneous transformer for an artificial heart.

PubMed

Shiba, Kenji; Nukaya, Masayuki; Tsuji, Toshio; Koshiji, Kohji

2008-01-01

This paper reports on the current density and specific absorption rate (SAR) analysis of biological tissue surrounding an air-core transcutaneous transformer for an artificial heart. The electromagnetic field in the biological tissue is analyzed by the transmission line modeling method, and the current density and SAR as a function of frequency, output voltage, output power, and coil dimension are calculated. The biological tissue of the model has three layers including the skin, fat, and muscle. The results of simulation analysis show SARs to be very small at any given transmission conditions, about 2-14 mW/kg, compared to the basic restrictions of the International Commission on nonionizing radiation protection (ICNIRP; 2 W/kg), while the current density divided by the ICNIRP's basic restrictions gets smaller as the frequency rises and the output voltage falls. It is possible to transfer energy below the ICNIRP's basic restrictions when the frequency is over 250 kHz and the output voltage is under 24 V. Also, the parts of the biological tissue that maximized the current density differ by frequencies; in the low frequency is muscle and in the high frequency is skin. The boundary is in the vicinity of the frequency 600-1000 kHz.

Responses of leaf stomatal density to water status and its relationship with photosynthesis in a grass.

PubMed

Xu, Zhenzhu; Zhou, Guangsheng

2008-01-01

Responses of plant leaf stomatal conductance and photosynthesis to water deficit have been extensively reported; however, little is known concerning the relationships of stomatal density with regard to water status and gas exchange. The responses of stomatal density to leaf water status were determined, and correlation with specific leaf area (SLA) in a photosynthetic study of a perennial grass, Leymus chinensis, subjected to different soil moisture contents. Moderate water deficits had positive effects on stomatal number, but more severe deficits led to a reduction, described in a quadratic parabolic curve. The stomatal size obviously decreased with water deficit, and stomatal density was positively correlated with stomatal conductance (g(s)), net CO(2) assimilation rate (A(n)), and water use efficiency (WUE). A significantly negative correlation of SLA with stomatal density was also observed, suggesting that the balance between leaf area and its matter may be associated with the guard cell number. The present results indicate that high flexibilities in stomatal density and guard cell size will change in response to water status, and this process may be closely associated with photosynthesis and water use efficiency.

Validation of phenol red versus gravimetric method for water reabsorption correction and study of gender differences in Doluisio's absorption technique.

PubMed

Tuğcu-Demiröz, Fatmanur; Gonzalez-Alvarez, Isabel; Gonzalez-Alvarez, Marta; Bermejo, Marival

2014-10-01

The aim of the present study was to develop a method for water flux reabsorption measurement in Doluisio's Perfusion Technique based on the use of phenol red as a non-absorbable marker and to validate it by comparison with gravimetric procedure. The compounds selected for the study were metoprolol, atenolol, cimetidine and cefadroxil in order to include low, intermediate and high permeability drugs absorbed by passive diffusion and by carrier mediated mechanism. The intestinal permeabilities (Peff) of the drugs were obtained in male and female Wistar rats and calculated using both methods of water flux correction. The absorption rate coefficients of all the assayed compounds did not show statistically significant differences between male and female rats consequently all the individual values were combined to compare between reabsorption methods. The absorption rate coefficients and permeability values did not show statistically significant differences between the two strategies of concentration correction. The apparent zero order water absorption coefficients were also similar in both correction procedures. In conclusion gravimetric and phenol red method for water reabsorption correction are accurate and interchangeable for permeability estimation in closed loop perfusion method. Copyright © 2014 Elsevier B.V. All rights reserved.

Outskirts of Distant Galaxies in Absorption

NASA Astrophysics Data System (ADS)

Chen, Hsiao-Wen

QSO absorption spectroscopy provides a sensitive probe of both the neutral medium and diffuse ionized gas in the distant Universe. It extends 21 cm maps of gaseous structures around low-redshift galaxies both to lower gas column densities and to higher redshifts. Combining galaxy surveys with absorption-line observations of gas around galaxies enables comprehensive studies of baryon cycles in galaxy outskirts over cosmic time. This chapter presents a review of the empirical understanding of the cosmic neutral gas reservoir from studies of damped Lyα absorbers (DLAs). It describes the constraints on the star formation relation and chemical enrichment history in the outskirts of distant galaxies from DLA studies. A brief discussion of available constraints on the ionized circumgalactic gas from studies of lower column density Lyα absorbers and associated ionic absorption transitions is presented at the end.

Method 200.12 - Determination of Trace Elements in Marine Waters by StabilizedTemperature Graphite Furnace Atomic Absorption

EPA Science Inventory

This method provides procedures for the determination of total recoverable elements by graphite furnace atomic absorption (GFAA) in marine waters, including estuarine, ocean and brines with salinities of up to 35 ppt.

Automated atomic absorption spectrometric determination of total arsenic in water and streambed materials

USGS Publications Warehouse

Fishman, M.

1977-01-01

An automated method to determine both inorganic and organic forms of arsenic In water, water-suspended mixtures, and streambed materials Is described. Organic arsenic-containing compounds are decomposed by either ultraviolet radiation or by suHurlc acid-potassium persulfate digestion. The arsenic liberated, with Inorganic arsenic originally present, is reduced to arsine with sodium borohydrlde. The arable Is stripped from the solution with the aid of nitrogen and Is then decomposed In a tube furnace heated to 800 ??C which Is placed in the optical path of an atomic absorption spectrometer. Thirty samples per hour can be analyzed to levels of 1 ??g arsenic per liter.

Density, structure, and dynamics of water: The effect of van der Waals interactions

NASA Astrophysics Data System (ADS)

Wang, Jue; Román-Pérez, G.; Soler, Jose M.; Artacho, Emilio; Fernández-Serra, M.-V.

2011-01-01

It is known that ab initio molecular dynamics (AIMD) simulations of liquid water at ambient conditions, based on the generalized gradient approximation (GGA) to density functional theory (DFT), with commonly used functionals fail to produce structural and diffusive properties in reasonable agreement with experiment. This is true for canonical, constant temperature simulations where the density of the liquid is fixed to the experimental density. The equilibrium density, at ambient conditions, of DFT water has recently been shown by Schmidt et al. [J. Phys. Chem. B, 113, 11959 (2009)] to be underestimated by different GGA functionals for exchange and correlation, and corrected by the addition of interatomic pair potentials to describe van der Waals (vdW) interactions. In this contribution we present a DFT-AIMD study of liquid water using several GGA functionals as well as the van der Waals density functional (vdW-DF) of Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)]. As expected, we find that the density of water is grossly underestimated by GGA functionals. When a vdW-DF is used, the density improves drastically and the experimental diffusivity is reproduced without the need of thermal corrections. We analyze the origin of the density differences between all the functionals. We show that the vdW-DF increases the population of non-H-bonded interstitial sites, at distances between the first and second coordination shells. However, it excessively weakens the H-bond network, collapsing the second coordination shell. This structural problem is partially associated to the choice of GGA exchange in the vdW-DF. We show that a different choice for the exchange functional is enough to achieve an overall improvement both in structure and diffusivity.

Differential Absorption Radar: An Emerging Technology for Remote Sounding of Water Vapor Within Clouds

NASA Astrophysics Data System (ADS)

Lebsock, M. D.; Millan Valle, L. F.; Cooper, K. B.; Siles, J.; Monje, R.

2017-12-01

We present the results of our efforts to build and demonstrate the first Differential Absorption Radar (DAR), which will provide unique capabilities to remotely sound for water vapor within cloudy and precipitating atmospheres. The approach leverages multiple radar channels located near the 183 GHz water vapor absorption feature to simultaneously derive microphysical and water vapor profiles. The DAR technique has the potential to neatly complement existing water vapor sounding techniques such as infrared and microwave sounding and GPS radio occultation. These precisions rival those of existing water vapor remote sensing instruments. The approach works best from above clouds because the water vapor burden and line width increases towards the Earth surface allowing increased sampling from the top-down compared with bottom-up. From an airborne or satellite platform channels can be selected that target either upper-tropospheric or lower-tropospheric clouds. Our theoretical studies suggest that the water vapor concentration can be retrieved to within 1-3 gm-3 and the column integrated water vapor can be retrieved to within 1 kgm-2. The high-frequency radar is only recently enabled by technological advances that have allowed us to demonstrate 0.5 W of continuous power near 183 GHz. We are currently developing an airborne DAR using a Frequency Modulated Continuous Wave (FMCW) architecture with a quasi-optical duplexer providing 80 dB of transmit/receive isolation. A prototype of this instrument recently made the first ever range resolved DAR measurements of humidity out to several hundred meters during a light rain event at JPL. The spectral dependence of the attenuation was in excellent agreement with the predicted attenuation based on nearby weather stations, proving for the first time the feasibility of the concept. A major impediment to implementing DAR is the international regulation of radio-frequency transmissions below 300 GHz. The major roadblocks and potential

Energy transmission transformer for a wireless capsule endoscope: analysis of specific absorption rate and current density in biological tissue.

PubMed

Shiba, Kenji; Nagato, Tomohiro; Tsuji, Toshio; Koshiji, Kohji

2008-07-01

This paper reports on the electromagnetic influences on the analysis of biological tissue surrounding a prototype energy transmission system for a wireless capsule endoscope. Specific absorption rate (SAR) and current density were analyzed by electromagnetic simulator in a model consisting of primary coil and a human trunk including the skin, fat, muscle, small intestine, backbone, and blood. First, electric and magnetic strength in the same conditions as the analytical model were measured and compared to the analytical values to confirm the validity of the analysis. Then, SAR and current density as a function of frequency and output power were analyzed. The validity of the analysis was confirmed by comparing the analytical values with the measured ones. The SAR was below the basic restrictions of the International Commission on Nonionizing Radiation Protection (ICNIRP). At the same time, the results for current density show that the influence on biological tissue was lowest in the 300-400 kHz range, indicating that it was possible to transmit energy safely up to 160 mW. In addition, we confirmed that the current density has decreased by reducing the primary coil's current.

Simulation model of a single-stage lithium bromide-water absorption cooling unit

NASA Technical Reports Server (NTRS)

Miao, D.

1978-01-01

A computer model of a LiBr-H2O single-stage absorption machine was developed. The model, utilizing a given set of design data such as water-flow rates and inlet or outlet temperatures of these flow rates but without knowing the interior characteristics of the machine (heat transfer rates and surface areas), can be used to predict or simulate off-design performance. Results from 130 off-design cases for a given commercial machine agree with the published data within 2 percent.

Two photon absorption laser induced fluorescence measurements of neutral density in a helicon plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galante, M. E.; Magee, R. M.; Scime, E. E.

2014-05-15

We have developed a new diagnostic based on two-photon absorption laser induced fluorescence (TALIF). We use a high intensity (5 MW/cm{sup 2}), narrow bandwidth (0.1 cm{sup −1}) laser to probe the ground state of neutral hydrogen, deuterium and krypton with spatial resolution better than 0.2 cm, a time resolution of 10 ns, and a measurement cadence of 20 Hz. Here, we describe proof-of-principle measurements in a helicon plasma source that demonstrate the TALIF diagnostic is capable of measuring neutral densities spanning four orders of magnitude; comparable to the edge neutral gradients predicted in the DIII-D tokamak pedestal. The measurements are performed in hydrogen and deuteriummore » plasmas and absolute calibration is accomplished through TALIF measurements in neutral krypton. The optical configuration employed is confocal, i.e., both light injection and collection are accomplished with a single lens through a single optical port in the vacuum vessel. The wavelength resolution of the diagnostic is sufficient to separate hydrogen and deuterium spectra and we present measurements from mixed hydrogen and deuterium plasmas that demonstrate isotopic abundance measurements are feasible. Time resolved measurements also allow us to explore the evolution of the neutral hydrogen density and temperature and effects of wall recycling. We find that the atomic neutral density grows rapidly at the initiation of the discharge, reaching the steady-state value within 1 ms. Additionally, we find that neutral hydrogen atoms are born with 0.08 eV temperatures, not 2 eV as is typically assumed.« less

Variability of absorption heat pump efficiency for domestic water heating and space heating based on time-weighted bin analysis

DOE PAGES

Ally, Moonis Raza; Sharma, Vishaldeep

2017-11-02

Natural gas-driven absorption heat pumps are under renewed scrutiny as a viable technology for space conditioning and water heating for residential and commercial applications because of natural gas production trends, pricing, and the speculation that it might be a “bridge fuel” in the global transition towards energy sustainability. Since any level of natural gas combustion contributes to atmospheric carbon dioxide accumulation, the merits of natural gas consuming absorption technology are re-examined in this paper from the point of view of expected efficiency throughout the United States using a time-weighted bin temperature analysis. Such analyses are necessary because equipment standards formore » rated performance is restricted to one set ambient condition, whereas in actual practice, the absorption heat pump (AHP) must perform over a considerably wider range of external conditions, where its efficiency may be vastly different from that at the rated condition. Quantification of variation in efficiency and system performance are imperative to address how to provide the desired utility with the least environmental impact. In this paper, we examine limiting features in absorption heat pumps and relate it to systemic performances in sixteen cities across all eight climate zones in the U.S, each containing fifteen bin temperatures. The results indicate that the true expectation of performance of an AHP is significantly less than what might be optimized for the rated condition. Statistical measures of the variation in water heating COPs show that for most cities, the COP at the rated conditions is outside the 95% Confidence Interval. Moreover, it is concluded that deployment of absorption heat pump water heaters (AHPWH) may be restricted geographically by outdoor temperature constraints.« less

Variability of absorption heat pump efficiency for domestic water heating and space heating based on time-weighted bin analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ally, Moonis Raza; Sharma, Vishaldeep

Natural gas-driven absorption heat pumps are under renewed scrutiny as a viable technology for space conditioning and water heating for residential and commercial applications because of natural gas production trends, pricing, and the speculation that it might be a “bridge fuel” in the global transition towards energy sustainability. Since any level of natural gas combustion contributes to atmospheric carbon dioxide accumulation, the merits of natural gas consuming absorption technology are re-examined in this paper from the point of view of expected efficiency throughout the United States using a time-weighted bin temperature analysis. Such analyses are necessary because equipment standards formore » rated performance is restricted to one set ambient condition, whereas in actual practice, the absorption heat pump (AHP) must perform over a considerably wider range of external conditions, where its efficiency may be vastly different from that at the rated condition. Quantification of variation in efficiency and system performance are imperative to address how to provide the desired utility with the least environmental impact. In this paper, we examine limiting features in absorption heat pumps and relate it to systemic performances in sixteen cities across all eight climate zones in the U.S, each containing fifteen bin temperatures. The results indicate that the true expectation of performance of an AHP is significantly less than what might be optimized for the rated condition. Statistical measures of the variation in water heating COPs show that for most cities, the COP at the rated conditions is outside the 95% Confidence Interval. Moreover, it is concluded that deployment of absorption heat pump water heaters (AHPWH) may be restricted geographically by outdoor temperature constraints.« less

Nonlinear Absorption and Heating of Dense Plasmas.

DTIC Science & Technology

plasma focus both illuminated by a high intensity CO2 laser. Results indicate the previously noted increases in absorption due to the inclusion of the nonlinear saturation mechanism. The previously obtained increases in absorption with increasing density scale height and decreasing temperatures are also recovered. The

Effect of oxalic acid pretreatment of wood chips on manufacturing medium-density fiberboard

Treesearch

Xianjun Li; Zhiyong Cai; Eric Horn; Jerrold E. Winandy

2011-01-01

The main objective of this study was to evaluate the effect of oxalic acid (OA) wood chips pretreatment prior to refining, which is done to reduce energy used during the refining process. Selected mechanical and physical performances of medium-density fiberboard (MDF) – internal bonding (IB), modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA)...

Evaluation of elastic properties and study on water absorption behavior of alumina filled jute-epoxy composites

NASA Astrophysics Data System (ADS)

Santosh, D. N.; Ravikumar, B. N.; Mahesh, B.; Vijayalaxmi, S. P.; Srinivas, Y. V.

2018-04-01

In this paper, the effect of filler content is studied on elastic properties and water absorption behavior for jute epoxy composite. For reinforcement the plain woven jute fabric is used. The bonding system consists of resin-epoxy and Hardener in the ratio 10:1 by weight. Alumina (average grain size of 30 µm) is used as filler. The effect of filler content on elastic properties and water absorption behavior studied by varying the filler content from 5%, 10%, 15% with respect to weight of epoxy. The open mould method used to fabricate the alumina filled jute-epoxy composite laminates. Tests were conducted according to ASTM standards. The evaluation assesment of elastic properties of alumina filled jute-epoxy composite materials have been analyzed by theoretically and experimentally. The speculated values are analyzed with those obtained from experimental to validate the calculated theoretically with rule of mixture procedure. Young's modulus and shear modulus were found to increase with the increase in the filler content upto 10 wt%, beyond which the modulii showed decreasing trend. Poisson's ratio was found to be continuously decreasing with the increase in the alumina filler content of jute-eposy composite. It was clearly observed that unfilled specimen has the highest saturated moisture content and 15% filled specimen has lowest value. As alumina filler content increases resistance to moisture absorption also increases. The water diffusion coefficient of composite was calculated using the diffusion coefficient equation. As filler content increases diffusion co-efficient decreases for alumina filled jute-epoxy composite.

Water vapor self-continuum absorption measurements in the 4.0 and 2.1 μm transparency windows

NASA Astrophysics Data System (ADS)

Richard, L.; Vasilchenko, S.; Mondelain, D.; Ventrillard, I.; Romanini, D.; Campargue, A.

2017-11-01

In a recent contribution [A. Campargue, S. Kassi, D. Mondelain, S. Vasilchenko, D. Romanini, Accurate laboratory determination of the near infrared water vapor self-continuum: A test of the MT_CKD model. J. Geophys. Res. Atmos., 121,13,180-13,203, doi:10.1002/2016JD025531], we reported accurate water vapor absorption continuum measurements by Cavity Ring-down Spectroscopy (CRDS) and Optical-Feedback-Cavity Enhanced Absorption Spectroscopy (OF-CEAS) at selected spectral points of 4 near infrared transparency windows. In the present work, the self-continuum cross-sections, CS, are determined for two new spectral points. The 2491 cm-1 spectral point in the region of maximum transparency of the 4.0 μm window was measured by OF-CEAS in the 23-52 °C temperature range. The 4435 cm-1 spectral point of the 2.1 μm window was measured by CRDS at room temperature. The self-continuum cross-sections were determined from the pressure squared dependence of the continuum absorption. Comparison to the literature shows a reasonable agreement with 1970 s and 1980 s measurements using a grating spectrograph in the 4.0 μm window and a very good consistency with our previous laser measurements in the 2.1 μm window. For both studied spectral points, our values are much smaller than previous room temperature measurements by Fourier Transform Spectroscopy. Significant deviations (up to about a factor 4) are noted compared to the widely used semi empirical MT_CKD model of the absorption continuum. The measured temperature dependence at 2491 cm-1 is consistent with previous high temperature measurements in the 4.0 μm window and follows an exp(D0/kT) law, D0 being the dissociation energy of the water dimer.

Light absorption properties of colored dissolved organic matter (CDOM) in adjacent waters of the Changjiang Estuary during a flood season: implication for DOC estimation

NASA Astrophysics Data System (ADS)

Liu, Yangyang; Shen, Fang; Li, Xiuzhen

2014-11-01

Light absorption properties of colored dissolved organic matter (CDOM) in adjacent waters of the Changjiang Estuary were investigated during the summer of 2013. CDOM absorption showed a substantial portion of the total absorption and clearly dominant among most investigation stations. It generally decreased from the northwest to the southeast, which controlled by physical mixing of fresh water and seawater as was indicated by a conservative behaviour of CDOM. CDOM absorption sharply increased during phytoplankton blooms. Similarly, dissolved organic carbon (DOC) also peaked during blooms period. However, DOC exhibited a more complex behavior relative to a simple conservative mixing, possibly attributed to multiple origins of DOC. CDOM absorption and DOC co-varied to some degree, implying a potential way of DOC estimation from CDOM absorption. However, more detailed information such as CDOM and DOC composition and more validation data were required to obtain a stable CDOM - DOC pattern. Lastly, empirical algorithms with limited data were developed to retrieve CDOM absorption. Further validation of the algorithms were needed when they were to be commonly applied.

Electrical transport properties of individual WS2 nanotubes and their dependence on water and oxygen absorption

NASA Astrophysics Data System (ADS)

Zhang, Chaoying; Ning, Zhiyuan; Liu, Yang; Xu, Tingting; Guo, Yao; Zak, Alla; Zhang, Zhiyong; Wang, Sheng; Tenne, Reshef; Chen, Qing

2012-09-01

The electrical properties of WS2 nanotubes (NTs) were studied through measuring 59 devices. Important electrical parameters, such as the carrier concentration, mobility, and effective barrier height at the contacts, were obtained through fitting experimental non-linear I-V curves using a metal-semiconductor-metal model. The carrier mobility was found to be several orders of magnitude higher than that have been reported previously for WS2 NTs. Water absorption was found to decrease the conductivity and carrier mobility of the NTs, and could be removed when the sample was dried. Oxygen absorption also slightly decreased the conductivity of WS2 NTs.

High Efficiency Water Heating Technology Development Final Report, Part II: CO 2 and Absorption-Based Residential Heat Pump Water Heater Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gluesenkamp, Kyle R.; Abdelaziz, Omar; Patel, Viral K.

2017-05-01

The two objectives of this project were to 1.demonstrate an affordable path to an ENERGY STAR qualified electric heat pump water heater (HPWH) based on low-global warming potential (GWP) CO 2 refrigerant, and 2.demonstrate an affordable path to a gas-fired absorption-based heat pump water heater with a gas energy factor (EF) greater than 1.0. The first objective has been met, and the project has identified a promising low-cost option capable of meeting the second objective. This report documents the process followed and results obtained in addressing these objectives.

Estimation of contrast of refraction contrast imaging compared with absorption imaging-basic approach.

PubMed

Hirano, Masatsugu; Yamasaki, Katsuhito; Okada, Hiroshi; Kitazawa, Sohei; Kitazawa, Riko; Ohno, Yoshiharu; Sakurai, Takashi; Kondoh, Takeshi; Ohbayashi, Chiho; Katafuchi, Tetsuro; Maeda, Sakan; Sugimura, Kazuro; Tamura, Shinichi

2005-03-01

We discuss the usefulness of the refraction contrast method using highly parallel X-rays as a new approach to minute lung cancer detection. The advantages of refraction contrast images are discussed in terms of contrast, and a comparison is made with absorption images. We simulated refraction contrast imaging using globules with the density of water in air as models for minute lung cancer detection. The contrast intensified by bright and dark lines was compared on a globule with the contrast of absorption images. We adopted the Monte Carlo simulation to determine the strength of the profile curve of the photon counts at the detector. The obtained contrasts were more intense by two to three digits than those obtainable with the absorption contrast imaging method. The contrast in refraction contrast imaging was more intense than that obtainable with absorption contrast imaging. A two to three digit improvement in contrast means that it is possible to greatly reduce the exposure dose necessary for imaging. Therefore, it is expected to become possible to detect the interfaces of soft tissues, which are difficult to capture with conventional absorption imaging, at low dosages and high resolution.

Global statistics of liquid water content and effective number density of water clouds over ocean derived from combined CALIPSO and MODIS measurements

NASA Astrophysics Data System (ADS)

Hu, Y.; Vaughan, M.; McClain, C.; Behrenfeld, M.; Maring, H.; Anderson, D.; Sun-Mack, S.; Flittner, D.; Huang, J.; Wielicki, B.; Minnis, P.; Weimer, C.; Trepte, C.; Kuehn, R.

2007-03-01

This study presents an empirical relation that links layer integrated depolarization ratios, the extinction coefficients, and effective radii of water clouds, based on Monte Carlo simulations of CALIPSO lidar observations. Combined with cloud effective radius retrieved from MODIS, cloud liquid water content and effective number density of water clouds are estimated from CALIPSO lidar depolarization measurements in this study. Global statistics of the cloud liquid water content and effective number density are presented.

Effects of stretching and stirring on water and glucose absorption by canine mucosal membrane.

PubMed Central

Lee, J S

1983-01-01

A 'mini' canine mucosal membrane preparation permitting simultaneous determination of water (Jv) and glucose (Jg) absorption rates, microscopic examination or micropuncture of the villi was used in this study. The small membranes were more stretched than the large ones, with more than a one-fold increase in both Jv and Jg, apparently due to a change in architectural orientation between the villi and subvillous supporting tissue so as to facilitate water transport via the lymphatic system. During stirring of the bathing solution, the villi in the small membranes were widely separated from each other with more to-and-fro swaying movements than in the large ones. Stirring was seen to cause up-and-down movements of the loosely suspended large membranes but not the small ones. In the small membranes stirring caused no change in Jv but an increase in Jg due to the increase in glucose concentration in the absorbate, while in the large membranes both Jv and Jg were greatly increased. It is thus considered that the increase in absorption in the large membranes caused by stirring is mainly due to the increased membrane movements promoting lymph flow. PMID:6875881

Prediction of Iron K-Edge Absorption Spectra Using Time-Dependent Density Functional Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

George, S.DeBeer; Petrenko, T.; Neese, F.

2009-05-14

Iron K-edge X-ray absorption pre-edge features have been calculated using a time-dependent density functional approach. The influence of functional, solvation, and relativistic effects on the calculated energies and intensities has been examined by correlation of the calculated parameters to experimental data on a series of 10 iron model complexes, which span a range of high-spin and low-spin ferrous and ferric complexes in O{sub h} to T{sub d} geometries. Both quadrupole and dipole contributions to the spectra have been calculated. We find that good agreement between theory and experiment is obtained by using the BP86 functional with the CP(PPP) basis setmore » on the Fe and TZVP one of the remaining atoms. Inclusion of solvation yields a small improvement in the calculated energies. However, the inclusion of scalar relativistic effects did not yield any improved correlation with experiment. The use of these methods to uniquely assign individual spectral transitions and to examine experimental contributions to backbonding is discussed.« less

Pyruvate-enriched oral rehydration solution improved intestinal absorption of water and sodium during enteral resuscitation in burns.

PubMed

Hu, Sen; Liu, Wei-wei; Zhao, Ying; Lin, Zhi-long; Luo, Hong-min; Bai, Xiao-dong; Sheng, Zhi-yong; Zhou, Fang-qiang

2014-06-01

To investigate alteration in intestinal absorption during enteral resuscitation with pyruvate-enriched oral rehydration solution (Pyr-ORS) in scalded rats. To compare pyruvate-enriched oral rehydration solution (Pyr-ORS) with World Health Organisation oral rehydration solution (WHO-ORS), 120 rats were randomly divided into 6 groups and 2 subgroups. At 1.5 and 4.5 h after a 35% TBSA scald, the intestinal absorption rate, mucosal blood flow (IMBF), Na(+)-K(+)-ATPase activity and aquaporin-1 (AQP-1) expression were determined (n = 10), respectively. The intestinal Na(+)-K(+)-ATPase activity, AQP-1 expression and IMBF were markedly decreased in scald groups, but they were profoundly preserved by enteral resuscitation with WHO-ORS and further improved significantly with Pyr-ORS at both time points. Na(+)-K+-ATPase activities remained higher in enteral resuscitation with Pyr-ORS (Group SP) than those with WHO-ORS (Group SW) at 4.5 h. AQP-1 and IMBF were significantly greater in Group SP than in Group SW at both time points. Intestinal absorption rates of water and sodium were obviously inhibited in scald groups; however, rates were also significantly preserved in Group SP than in Group SW with an over 20% increment at both time points. The Pyr-ORS may be superior to the standard WHO-ORS in the promotion of intestinal absorption of water and sodium during enteral resuscitation. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Influence of temperature on water and aqueous glucose absorption spectra in the near- and mid-infrared regions at physiologically relevant temperatures.

PubMed

Jensen, Peter Snoer; Bak, Jimmy; Andersson-Engels, Stefan

2003-01-01

Near- and mid-infrared absorption spectra of pure water and aqueous 1.0 g/dL glucose solutions in the wavenumber range 8000-950 cm-1 were measured in the temperature range 30-42 degrees C in steps of 2 degrees C. Measurements were carried out with an FT-IR spectrometer and a variable pathlength transmission cell controlled within 0.02 degree C. Pathlengths of 50 microns and 0.4 mm were used in the mid- and near-infrared spectral region, respectively. Difference spectra were used to determine the effect of temperature on the water spectra quantitatively. These spectra were obtained by subtracting the 37 degrees C water spectrum from the spectra measured at other temperatures. The difference spectra reveal that the effect of temperature is highest in the vicinity of the strong absorption bands, with a number of isosbestic points with no temperature dependence and relatively flat plateaus in between. On the basis of these spectra, prospects for and limitations on data analysis for infrared diagnostic methods are discussed. As an example, the absorptive properties of glucose were studied in the same temperature range in order to determine the effect of temperature on the spectral shape of glucose. The change in water absorption associated with the addition of glucose has also been studied. An estimate of these effects is given and is related to the expected level of infrared signals from glucose in humans.

Absorption of nutrients is only slightly reduced by supplementing enteral formulas with viscous fiber in miniature pigs.

PubMed

Ehrlein, H; Stockmann, A

1998-12-01

Viscous polysaccharides reduce intestinal absorption of glucose and diminish postprandial hyperglycemia. However, it is unknown whether viscous fiber also inhibits absorption of nutrients under conditions of enteric feeding. Therefore, we measured the absorption rates of nutrients in miniature pigs by perfusing a 150-cm length of jejunum with 8.37 kJ/min of the three following enteral diets: an isoosmotic oligomeric diet (1670 kJ/L), a hyperosmotic oligomeric diet and an isoosmotic polymeric diet (both 3350 kJ/L). The diets were supplemented with guar gum from 0 to 4.4 g/L. With the three guar-free diets, the mean absorption rate of energy was 5.2 +/- 0.32 kJ/min, corresponding to 62% of the energy infused. Absorption rates of carbohydrate, protein, fat and energy linearly declined as concentrations of guar or the logarithm of chyme viscosity increased. Due to modulations in viscosity, the inhibitory effects of guar were significantly different among the three diets. With the isoosmotic and hyperosmotic oligomeric and the polymeric diets, the addition of 1 g guar/L diminished the absorption of energy by 9.7, 6. 6 and 3.7%, respectively. The strong inhibitory effect on nutrient absorption with the isoosmotic oligomeric diet was caused by an increase in chyme viscosity due to water absorption. With the hyperosmotic oligomeric and the polymeric diets, the chyme viscosity and thus inhibitory effects on absorption were diminished by water secretion and the concomitant infusion of pancreatic enzymes. Results indicate that the addition of small amounts of guar gum to enteral diets of high energy density exerts only small effects on absorption of nutrients.

Absorption of the laser radiation by the laser plasma with gas microjet targets

NASA Astrophysics Data System (ADS)

Borisevichus, D. A.; Zabrodskii, V. V.; Kalmykov, S. G.; Sasin, M. E.; Seisyan, R. P.

2017-01-01

An upper limit of absorption of the laser radiation in the plasma produced in a gas jet Xe target with the average density of (3-6) × 1018 cm-3 and the effective diameter of 0.7 mm is found. It is equal to ≈50% and remains constant under any variation in this range of densities. This result contradicts both theoretical assessments that have predicted virtually complete absorption and results of earlier experiments with the laser spark in an unlimited stationary Xe gas with the same density, where the upper limit of absorption was close to 100%. An analysis shows that nonlinearity of absorption and plasma nonequilibrium lead to the reduction of the absorption coefficient that, along with the limited size of plasma, can explain the experimental results.

On the origin of the water vapor continuum absorption within rotational and fundamental vibrational bands

NASA Astrophysics Data System (ADS)

Serov, E. A.; Odintsova, T. A.; Tretyakov, M. Yu.; Semenov, V. E.

2017-05-01

Analysis of the continuum absorption in water vapor at room temperature within the purely rotational and fundamental ro-vibrational bands shows that a significant part (up to a half) of the observed absorption cannot be explained within the framework of the existing concepts of the continuum. Neither of the two most prominent mechanisms of continuum originating, namely, the far wings of monomer lines and the dimers, cannot reproduce the currently available experimental data adequately. We propose a new approach to developing a physically based model of the continuum. It is demonstrated that water dimers and wings of monomer lines may contribute equally to the continuum within the bands, and their contribution should be taken into account in the continuum model. We propose a physical mechanism giving missing justification for the super-Lorentzian behavior of the intermediate line wing. The qualitative validation of the proposed approach is given on the basis of a simple empirical model. The obtained results are directly indicative of the necessity to reconsider the existing line wing theory and can guide this consideration.

Effect of intravenous ranitidine and omeprazole on intestinal absorption of water, sodium, and macronutrients in patients with intestinal resection

PubMed Central

Jeppesen, P; Staun, M; Tjellesen, L; Mortensen, P

1998-01-01

Background—H2 receptor blockers and proton pump inhibitors reduce intestinal output in patients with short bowel syndrome. 
Aims—To evaluate the effect of intravenous omeprazole and ranitidine on water, electrolyte, macronutrient, and energy absorption in patients with intestinal resection. 
Methods—Thirteen patients with a faecal weight above 1.5 kg/day (range 1.7-5.7 kg/day and a median small bowel length of 100cm were studied. Omeprazole 40 mg twice daily or ranitidine 150mg twice daily were administered for five days in a randomised, double blind, crossover design followed by a three day control period with no treatment. Two patients with a segment of colon in continuation were excluded from analysis which, however, had no influence on the results. 
Results—Omeprazole increased median intestinal wet weight absorption compared with no treatment and ranitidine (p<0.03). The effect of ranitidine was not significant. Four patients with faecal volumes below 2.6 kg/day did not respond to omeprazole; in two absorption increased by 0.5-1 kg/day; and in five absorption increased by 1−2 kg/day. Absorption of sodium, calcium, magnesium, nitrogen, carbohydrate, fat, and total energy was unchanged. Four high responders continued on omeprazole for 12-15 months, but none could be weaned from parenteral nutrition. 
Conclusion—Omeprazole increased water absorption in patients with faecal output above 2.50 kg/day. The effect varied significantly and was greater in patients with a high output, but did not allow parenteral nutrition to be discontinued. Absorption of energy, macronutrients, electrolytes, and divalent cations was not improved. The effect of ranitidine was not significant, possibly because the dose was too low. 

 Keywords: short bowel syndrome; human; diarrhoea; ranitidine; omeprazole PMID:9824602

Comment on "Hydrogen Balmer beta: The separation between line peaks for plasma electron density diagnostics and self-absorption test"

NASA Astrophysics Data System (ADS)

Gautam, Ghaneshwar; Surmick, David M.; Parigger, Christian G.

2015-07-01

In this letter, we present a brief comment regarding the recently published paper by Ivković et al., J Quant Spectrosc Radiat Transf 2015;154:1-8. Reference is made to previous experimental results to indicate that self absorption must have occurred; however, when carefully considering error propagation, both widths and peak-separation predict electron densities within the error margins. Yet the diagnosis method and the presented details on the use of the hydrogen beta peak separation are viewed as a welcomed contribution in studies of laser-induced plasma.

Gamma radiation induces hydrogen absorption by copper in water

NASA Astrophysics Data System (ADS)

Lousada, Cláudio M.; Soroka, Inna L.; Yagodzinskyy, Yuriy; Tarakina, Nadezda V.; Todoshchenko, Olga; Hänninen, Hannu; Korzhavyi, Pavel A.; Jonsson, Mats

2016-04-01

One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste. These repositories can have an impact on future generations for a period of time orders of magnitude longer than any known civilization. Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel. Among the many processes that must be considered in the safety assessments, radiation induced processes constitute a key-component. Here we show that copper metal immersed in water uptakes considerable amounts of hydrogen when exposed to γ-radiation. Additionally we show that the amount of hydrogen absorbed by copper depends on the total dose of radiation. At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system. Moreover, irradiation of copper in water causes corrosion of the metal and the formation of a variety of surface cavities, nanoparticle deposits, and islands of needle-shaped crystals. Hence, radiation enhanced uptake of hydrogen by spent nuclear fuel encapsulating materials should be taken into account in the safety assessments of nuclear waste repositories.

Density functional theory study on carbon dioxide absorption into aqueous solutions of 2-amino-2-methyl-1-propanol using a continuum solvation model.

PubMed

Yamada, Hidetaka; Matsuzaki, Yoichi; Higashii, Takayuki; Kazama, Shingo

2011-04-14

We used density functional theory (DFT) calculations with the latest continuum solvation model (SMD/IEF-PCM) to determine the mechanism of CO(2) absorption into aqueous solutions of 2-amino-2-methyl-1-propanol (AMP). Possible absorption process reactions were investigated by transition-state optimization and intrinsic reaction coordinate (IRC) calculations in the aqueous solution at the SMD/IEF-PCM/B3LYP/6-31G(d) and SMD/IEF-PCM/B3LYP/6-311++G(d,p) levels of theory to determine the absorption pathways. We show that the carbamate anion forms by a two-step reaction via a zwitterion intermediate, and this occurs faster than the formation of the bicarbonate anion. However, we also predict that the carbamate readily decomposes by a reverse reaction rather than by hydrolysis. As a result, the final product is dominated by the thermodynamically stable bicarbonate anion that forms from AMP, H(2)O, and CO(2) in a single-step termolecular reaction.

RF Path and Absorption Loss Estimation for Underwater Wireless Sensor Networks in Different Water Environments

PubMed Central

Qureshi, Umair Mujtaba; Shaikh, Faisal Karim; Aziz, Zuneera; Shah, Syed M. Zafi S.; Sheikh, Adil A.; Felemban, Emad; Qaisar, Saad Bin

2016-01-01

Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz. PMID:27322263

RF Path and Absorption Loss Estimation for Underwater Wireless Sensor Networks in Different Water Environments.

PubMed

Qureshi, Umair Mujtaba; Shaikh, Faisal Karim; Aziz, Zuneera; Shah, Syed M Zafi S; Sheikh, Adil A; Felemban, Emad; Qaisar, Saad Bin

2016-06-16

Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz.

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.

[Spatial variation characteristics of surface soil water content, bulk density and saturated hydraulic conductivity on Karst slopes].

PubMed

Zhang, Chuan; Chen, Hong-Song; Zhang, Wei; Nie, Yun-Peng; Ye, Ying-Ying; Wang, Ke-Lin

2014-06-01

Surface soil water-physical properties play a decisive role in the dynamics of deep soil water. Knowledge of their spatial variation is helpful in understanding the processes of rainfall infiltration and runoff generation, which will contribute to the reasonable utilization of soil water resources in mountainous areas. Based on a grid sampling scheme (10 m x 10 m) and geostatistical methods, this paper aimed to study the spatial variability of surface (0-10 cm) soil water content, soil bulk density and saturated hydraulic conductivity on a typical shrub slope (90 m x 120 m, projected length) in Karst area of northwest Guangxi, southwest China. The results showed that the surface soil water content, bulk density and saturated hydraulic conductivity had different spatial dependence and spatial structure. Sample variogram of the soil water content was fitted well by Gaussian models with the nugget effect, while soil bulk density and saturated hydraulic conductivity were fitted well by exponential models with the nugget effect. Variability of soil water content showed strong spatial dependence, while the soil bulk density and saturated hydraulic conductivity showed moderate spatial dependence. The spatial ranges of the soil water content and saturated hydraulic conductivity were small, while that of the soil bulk density was much bigger. In general, the soil water content increased with the increase of altitude while it was opposite for the soil bulk densi- ty. However, the soil saturated hydraulic conductivity had a random distribution of large amounts of small patches, showing high spatial heterogeneity. Soil water content negatively (P < 0.01) correlated with the bulk density and saturated hydraulic conductivity, while there was no significant correlation between the soil bulk density and saturated hydraulic conductivity.

An analysis of OH excited state absorption lines in DR 21 and K3-50

NASA Astrophysics Data System (ADS)

Jones, K. N.; Doel, R. C.; Field, D.; Gray, M. D.; Walker, R. N. F.

1992-10-01

We present an analysis of the OH absorption line zones observed toward the compact H II regions DR 21 and K3-50. Using as parameters the kinetic and dust temperatures, the H2 number density and the ratio of OH-H2 number densities to the velocity gradient, the model quantitatively reproduces the absorption line data for the six main line transitions in 2 Pi3/2 J = 5/2, 7/2, and 9/2. Observed upper limits for the absorption or emission in the satellite lines of 2 Pi3/2 J = 5/2 are crucial in constraining the range of derived parameters. Physical conditions derived for DR 21 show that the kinetic temperature centers around 140 K, the H2 number density around 10 exp 7/cu cm, and that the OH column density in the excited state absorption zone lies between 1 x 10 exp 15/sq cm and 2 x 10 exp 15/sq cm. Including contributions from a J = 3/2 absorption zone, the total OH column density is more than a factor of 2 lower than estimates based upon LTE (Walmsley et al., 1986). The OH absorption zone in K3-50 tends toward higher density and displays a larger column density, while the kinetic temperature is similar. For both sources, the dust temperature is found to be significantly lower than the kinetic temperature.

Neutronic performance of high-density LEU fuels in water-moderated and water-reflected research reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bretscher, M.M.; Matos, J.E.

At the Reduced Enrichment for Research and Test Reactors (RERTR) meeting in September 1994, Durand reported that the maximum uranium loading attainable with U{sub 3}Si{sub 2} fuel is about 6.0 g U/cm{sup 3}. The French Commissariat a l`Energie Atomique (CEA) plan to perform irradiation tests with 5 plates at this loading. Compagnie pour L`Etude et La Realisation de Combustibles Atomiques (CERCA) has also fabricated a few uranium nitride (UN) plates with a uranium density in the fuel meat of 7.0 g/cm{sup 3} and found that UN is compatible with the aluminum matrix at temperatures below 500 C. High density dispersionmore » fuels proposed for development include U-Zr(4 wt%)-Nb(2 wt%), U-Mo(5 wt%), and U-Mo(9 wt%). The purpose of this note is to examine the relative neutronic behavior of these high density fuels in a typical light water-reflected and water-moderated MTR-type research reactor. The results show that a dispersion of the U-Zr-Nb alloy has the most favorable neutronic properties and offers the potential for uranium densities greater than 8.0 g/cm{sup 3}. On the other hand, UN is the least reactive fuel because of the relatively large {sup 14}N(n,p) cross section. For a fixed value of k{sub eff}, the required {sup 235}U loading per fuel element is least for the U-Zr-Nb fuel and steadily increases for the U-Mo(5%), U-Mo(9%), and UN fuels. Because of volume fraction limitations, the UO{sub 2} dispersions are only useful for uranium densities below 5.0 g/cm{sup 3}. In this density range, however, UO{sub 2} is more reactive than U{sub 3}Si{sub 2}.« less

Nonlinear absorption dynamics using field-induced surface hopping: zinc porphyrin in water.

PubMed

Röhr, Merle I S; Petersen, Jens; Wohlgemuth, Matthias; Bonačić-Koutecký, Vlasta; Mitrić, Roland

2013-05-10

We wish to present the application of our field-induced surface-hopping (FISH) method to simulate nonlinear absorption dynamics induced by strong nonresonant laser fields. We provide a systematic comparison of the FISH approach with exact quantum dynamics simulations on a multistate model system and demonstrate that FISH allows for accurate simulations of nonlinear excitation processes including multiphoton electronic transitions. In particular, two different approaches for simulating two-photon transitions are compared. The first approach is essentially exact and involves the solution of the time-dependent Schrödinger equation in an extended manifold of excited states, while in the second one only transiently populated nonessential states are replaced by an effective quadratic coupling term, and dynamics is performed in a considerably smaller manifold of states. We illustrate the applicability of our method to complex molecular systems by simulating the linear and nonlinear laser-driven dynamics in zinc (Zn) porphyrin in the gas phase and in water. For this purpose, the FISH approach is connected with the quantum mechanical-molecular mechanical approach (QM/MM) which is generally applicable to large classes of complex systems. Our findings that multiphoton absorption and dynamics increase the population of higher excited states of Zn porphyrin in the nonlinear regime, in particular in solution, provides a means for manipulating excited-state properties, such as transient absorption dynamics and electronic relaxation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

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

2014-09-01

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

Absolute ozone absorption cross section in the Huggins Chappuis minimum (350-470 nm) at 296 K

NASA Astrophysics Data System (ADS)

Axson, J. L.; Washenfelder, R. A.; Kahan, T. F.; Young, C. J.; Vaida, V.; Brown, S. S.

2011-08-01

We report the ozone absolute absorption cross section between 350-470 nm, the minimum between the Huggins and Chappuis bands, where the ozone cross section is less than 10-22 cm2. Ozone spectra were acquired using an incoherent broadband cavity enhanced absorption spectrometer, with three channels centered at 365, 405, and 455 nm. The accuracy of the measured cross section is 2 %. Previous measurements vary by more than an order of magnitude in this spectral region. The measurements reported here provide much greater spectral coverage than the most recent measurements. We report a minimum absorption cross section of 3.4×10-24 cm2 at 381.8 nm, which is 22 % lower than the previously reported value. The effect of O3 concentration and water vapor partial pressure were investigated, however there were no observable changes in the absorption spectrum most likely due to the low optical density of the complex.

Auto-oligomerization and hydration of pyrrole revealed by x-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Advanced Light Source; Schwartz, Craig P.; Uejio, Janel S.

Near edge x-ray absorption fine structure (NEXAFS) spectra have been measured at the carbon and nitrogen K-edges of the prototypical aromatic molecule, pyrrole, both in the gas phase and when solvated in water, and compared with spectra simulated using a combination of classical molecular dynamics and first principles density functional theory in the excited state core hole approximation. The excellent agreement enabled detailed assignments. Pyrrole is highly reactive, particularly in water, and reaction products formed by the auto-oligomerization of pyrrole are identified. The solvated spectra have been measured at two different temperatures, indicating that the final states remain largely unaffectedmore » by both hydration and temperature. This is somewhat unexpected, since the nitrogen in pyrrole can donate a hydrogen bond to water.« less

Auto-oligomerization and hydration of pyrrole revealed by x-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Craig P.; Uejio, Janel S.; Duffin, Andrew M.

Near edge x-ray absorption fine structure spectra have been measured at the carbon and nitrogen K-edges of the prototypical aromatic molecule, pyrrole, both in the gas phase and when solvated in water, and compared with spectra simulated using a combination of classical molecular dynamics and first principles density functional theory in the excited state core hole approximation. The excellent agreement enabled detailed assignments. Pyrrole is highly reactive, particularly in water, and reaction products formed by the auto-oligomerization of pyrrole are identified. The solvated spectra have been measured at two different temperatures, indicating that the final states remain largely unaffected bymore » both hydration and temperature. This is somewhat unexpected, since the nitrogen in pyrrole can donate a hydrogen bond to water.« less

Lidar point density analysis: implications for identifying water bodies

USGS Publications Warehouse

Worstell, Bruce B.; Poppenga, Sandra K.; Evans, Gayla A.; Prince, Sandra

2014-01-01

Most airborne topographic light detection and ranging (lidar) systems operate within the near-infrared spectrum. Laser pulses from these systems frequently are absorbed by water and therefore do not generate reflected returns on water bodies in the resulting void regions within the lidar point cloud. Thus, an analysis of lidar voids has implications for identifying water bodies. Data analysis techniques to detect reduced lidar return densities were evaluated for test sites in Blackhawk County, Iowa, and Beltrami County, Minnesota, to delineate contiguous areas that have few or no lidar returns. Results from this study indicated a 5-meter radius moving window with fewer than 23 returns (28 percent of the moving window) was sufficient for delineating void regions. Techniques to provide elevation values for void regions to flatten water features and to force channel flow in the downstream direction also are presented.

Arbuscular mycorrhizal mediation of biomass-density relationship of Medicago sativa L. under two water conditions in a field experiment.

PubMed

Zhang, Qian; Xu, Liming; Tang, Jianjun; Bai, Minge; Chen, Xin

2011-05-01

The biomass-density relationship (whereby the biomass of individual plants decreases as plant density increases) has generally been explained by competition for resources. Arbuscular mycorrhizal fungi (AMF) are able to affect plant interactions by mediating resource utilization, but whether this AMF-mediated interaction will change the biomass-density relationship is unclear. We conducted an experiment to test the hypothesis that AMF will shift the biomass-density relationship by affecting intraspecific competition. Four population densities (10, 100, 1,000, or 10,000 seedlings per square meter) of Medicago sativa L. were planted in field plots. Water application (1,435 or 327.7 mm/year) simulated precipitation in wet areas (sufficient water) and arid areas (insufficient water). The fungicide benomyl was applied to suppress AMF in some plots ("low-AMF" treatment) and not in others ("high-AMF" treatment). The effect of the AMF treatment on the biomass-density relationship depended on water conditions. High AMF enhanced the decrease of individual biomass with increasing density (the biomass-density line had a steeper slope) when water was sufficient but not when water was insufficient. AMF treatment did not affect plant survival rate or population size but did affect absolute competition intensity (ACI). When water was sufficient, ACI was significantly higher in the high-AMF treatment than in the low-AMF treatment, but ACI was unaffected by AMF treatment when water was insufficient. Our results suggest that AMF status did not impact survival rate and population size but did shift the biomass-density relationship via effects on intraspecific competition. This effect of AMF on the biomass-density relationship depended on the availability of water.

Improvement of intestinal absorption of forsythoside A in weeping forsythia extract by various absorption enhancers based on tight junctions.

PubMed

Zhou, Wei; Qin, Kun Ming; Shan, Jin Jun; Ju, Wen Zheng; Liu, Shi Jia; Cai, Bao Chang; Di, Liu Qing

2012-12-15

Forsythoside A (FTA), one of the main active ingredients in weeping forsythia extract, possesses strong antibacterial, antioxidant and antiviral effects, and its content was about 8% of totally, higher largely than that of other ingredients, but the absolute bioavailability orally was approximately 0.5%, which is significant low influencing clinical efficacies of its oral preparations. In the present study, in vitro Caco-2 cell, in situ single-pass intestinal perfusion and in vivo pharmacokinetics study were performed to investigate the effects of absorption enhancers based on tight junctions: sodium caprate and water-soluble chitosan on the intestinal absorption of FTA, and the eventual mucosal epithelial damage resulted from absorption enhancers was evaluated by MTT test, measurement of total amount of protein and the activity of LDH and morphology observation, respectively. The pharmacological effects such as antioxidant activity improvement by absorption enhancers were verified by PC12 cell damage inhibition rate after H₂O₂ insults. The observations from in vitro Caco-2 cell showed that the absorption of FTA in weeping forsythia extract could be improved by absorption enhancers. Meanwhile, the absorption enhancing effect of water-soluble chitosan may be almost saturable up to 0.0032% (w/v), and sodium caprate at concentrations up to 0.64 mg/ml was safe for the Caco-2 cells, but water-soluble chitosan at different concentrations was all safe for these cells. The observations from single-pass intestinal perfusion in situ model showed that duodenum, jejunum, ileum and colon showed significantly concentration-dependent increase in P(eff)-value, and that P(eff)-value in the ileum and colon groups, where sodium caprate was added, was higher than that of duodenum and jejunum groups, but P(eff)-value in the jejunum group was higher than that of duodenum, ileum and colon groups where water-soluble chitosan was added. Intestinal mucosal toxicity studies showed no

Corrosion inhibitor for aqueous ammonia absorption system

DOEpatents

Phillips, Benjamin A.; Whitlow, Eugene P.

1998-09-22

A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

Corrosion inhibitor for aqueous ammonia absorption system

DOEpatents

Phillips, B.A.; Whitlow, E.P.

1998-09-22

A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

A far wing line shape theory and its application to the foreign-broadened water continuum absorption. III

NASA Technical Reports Server (NTRS)

Ma, Q.; Tipping, R. H.

1992-01-01

The far wing line shape theory developed previously and applied to the calculation of the continuum absorption of pure water vapor is extended to foreign-broadened continua. Explicit results are presented for H2O-N2 and H2O-CO2 in the frequency range from 0 to 10,000/cm. For H2O-N2 the positive and negative resonant frequency average line shape functions and absorption coefficients are computed for a number of temperatures between 296 and 430 K for comparison with available laboratory data. In general the agreement is very good.

Spectral Absorption Properties of Atmospheric Aerosols

NASA Technical Reports Server (NTRS)

Bergstrom, R. W.; Pilewskie, P.; Russell, P. B.; Redemann, J.; Bond, T. C.; Quinn, P. K.; Sierau, B.

2007-01-01

We have determined the solar spectral absorption optical depth of atmospheric aerosols for specific case studies during several field programs (three cases have been reported previously; two are new results). We combined airborne measurements of the solar net radiant flux density and the aerosol optical depth with a detailed radiative transfer model for all but one of the cases. The field programs (SAFARI 2000, ACE Asia, PRIDE, TARFOX, INTEX-A) contained aerosols representing the major absorbing aerosol types: pollution, biomass burning, desert dust and mixtures. In all cases the spectral absorption optical depth decreases with wavelength and can be approximated with a power-law wavelength dependence (Absorption Angstrom Exponent or AAE). We compare our results with other recent spectral absorption measurements and attempt to briefly summarize the state of knowledge of aerosol absorption spectra in the atmosphere. We discuss the limitations in using the AAE for calculating the solar absorption. We also discuss the resulting spectral single scattering albedo for these cases.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of antimony by automated-hydride atomic absorption spectrophotometry

USGS Publications Warehouse

Brown, G.E.; McLain, B.J.

1994-01-01

The analysis of natural-water samples for antimony by automated-hydride atomic absorption spectrophotometry is described. Samples are prepared for analysis by addition of potassium and hydrochloric acid followed by an autoclave digestion. After the digestion, potassium iodide and sodium borohydride are added automatically. Antimony hydride (stibine) gas is generated, then swept into a heated quartz cell for determination of antimony by atomic absorption spectrophotometry. Precision and accuracy data are presented. Results obtained on standard reference water samples agree with means established by interlaboratory studies. Spike recoveries for actual samples range from 90 to 114 percent. Replicate analyses of water samples of varying matrices give relative standard deviations from 3 to 10 percent.

Fabrication of novel chitosan/PAN/magnetic ZSM-5 zeolite coated sponges for absorption of oil from water surfaces.

PubMed

Samadi, Saman; Yazd, Shabnam Sharif; Abdoli, Hossein; Jafari, Pooya; Aliabadi, Majid

2017-12-01

In the present study, the chitosan (bottom layer)/polyacrylonitrile (top layer, PAN) nanofibers were coated on the sponge surface. The synthesized magnetic Fe 3 O 4 - ZSM-5 nanozeolites have been loaded into the chitosan/PAN nanofibers to increase the performance of nanofibers toward absorption of lubricating oil, motor oil and pump oil from water surfaces. Scanning electron microscope (SEM), Transmission electron microscope (TEM) and X-ray diffraction (XRD) analysis were used to characterize the synthesized nanozeolites. The morphology and wettability of nanofibers were determined using SEM and water contact angle tests. The influence of Fe 3 O 4 - ZSM-5 nanozeolite content and chitosan/PAN/Fe 3 O 4 - ZSM-5 nanofiber thickness was evaluated on the potential of sponges for oils absorption. The maximum capacity of the chitosan/PAN/Fe 3 O 4 - ZSM-5 nanofibers coated sponges for absorption of motor oil, lubricating oil and pump oil was found to be 99.4, 95.3 and 88.1g/g, in Fe 3 O 4 - ZSM-5 2wt.% and nanofiber thickness of 12μm (chitosan layer of 2μm and PAN layer of 10μm). The reusability of nanofibrous sponges showed that the hydrophobic chitosan/PAN/Fe 3 O 4 - ZSM-5 nanofibers coated sponges can be easily reused in water-oil separation for many cycles. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultraviolet absorption experiment MA-059

NASA Technical Reports Server (NTRS)

Donahue, T. M.; Hudson, R. D.; Anderson, J.; Kaufman, F.; Mcelroy, M. B.

1976-01-01

The ultraviolet absorption experiment performed during the Apollo Soyuz mission involved sending a beam of atomic oxygen and atomic nitrogen resonance radiation, strong unabsorbable oxygen and nitrogen radiation, and visual radiation, all filling the same 3 deg-wide field of view from the Apollo to the Soyuz. The radiation struck a retroreflector array on the Soyuz and was returned to a spectrometer onboard the Apollo. The density of atomic oxygen and atomic nitrogen between the two spacecraft was measured by observing the amount of resonance radiation absorbed when the line joining Apollo and Soyuz was perpendicular to their velocity with respect to the ambient atmosphere. Information concerning oxygen densities was also obtained by observation of resonantly fluorescent light. The absorption experiments for atomic oxygen and atomic nitrogen were successfully performed at a range of 500 meters, and abundant resonance fluorescence data were obtained.

Absorption properties of chromophoric dissolved organic matter (CDOM) in the East China Sea and the waters off eastern Taiwan

NASA Astrophysics Data System (ADS)

Zhou, Fengxia; Gao, Xuelu; Song, Jinming; Chen, Chen-Tung Arthur; Yuan, Huamao; Xing, Qianguo

2018-05-01

The absorption properties of chromophoric dissolved organic matter (CDOM) in the East China Sea (ECS) and the waters off eastern Taiwan (WET) were studied during May 2014. CDOM absorption coefficient (a280) and spectral slope (S275-295) revealed considerable spatial variations. In the ECS, the values of a280 and S275-295 presented a reverse distribution pattern. In the WET, a280 values were generally low while S275-295 values were generally high. Vertical distributions of a280 and S275-295 also varied in different regions. Terrestrial input, phytoplankton production, sediment release or photobleaching may be responsible for the dynamics of CDOM. Relationships among CDOM related parameters could partly support this conclusion. a280 were also used to trace different water masses and the result showed that the influence of Changjiang Diluted Water could reach the outer shelf of the northern ECS, and that the Kuroshio Current had a strong influence on the middle shelf of the southern ECS.

Measurements of spectral parameters of water-vapour transitions near 1388 and 1345 nm for accurate simulation of high-pressure absorption spectra

NASA Astrophysics Data System (ADS)

Liu, Xiang; Jeffries, Jay B.; Hanson, Ronald K.

2007-05-01

Quantitative near-infrared absorption spectroscopy of water-vapour overtone and combination bands at high pressures is complicated by pressure broadening and shifting of individual lines and the blending of neighbouring transitions. An experimental and computational methodology is developed to determine accurate high-pressure absorption spectra. This case study investigates two water-vapour transitions, one near 1388 nm (7203.9 cm-1) and the other near 1345 nm (7435.6 cm-1), for potential two-line absorption measurements of temperature in the range of 400-1050 K with a pressure varying from 5-25 atm. The required quantitative spectroscopy data (line strength, collisional broadening, and pressure-induced frequency shift) of the target transitions and their neighbours (a total of four H2O vapour transitions near 1388 nm and six transitions near 1345 nm) are measured in neat H2O vapour, H2O-air and H2O-CO2 mixtures as a function of temperature (296-1000 K) at low pressures (<800 Torr). Precise values of the line strength S(T), pressure-broadening coefficients γair(T) and \\gamma _{CO_2 } (T), and pressure-shift coefficients δair(T) and \\delta _{CO_2 } (T) for the ten transitions were inferred from the measured spectra and compared with data from HITRAN 2004. A hybrid spectroscopic database was constructed by modifying HITRAN 2004 to incorporate these values for simulation of water-vapour-absorption spectra at high pressures. Simulations using this hybrid database are in good agreement with high pressure experiments and demonstrate that data collected at modest pressures can be used to simulate high-pressure absorption spectra.

Peculiarities of light absorption by spherical microcapsules

NASA Astrophysics Data System (ADS)

Geints, Yurii E.; Panina, Ekaterina K.; Zemlyanov, Alexander A.

2018-04-01

Optical radiation absorption in the poly-layer spherical microparticles simulating the inorganic/organic polyshell absorbing microcapsules is considered. With the aim of the finite-difference time-domain technique, the spatial distribution of the absorbed light power in microcapsules of various sizes and internal structure is numerically calculated. For the purpose of light absorption enhancement, we have engineered the optimal structure of a capsule consisting of a strong-refracting transparent outer coating and an absorbing layer which covers a liquid core. The proposed microcapsule prototype provides for a manifold increase in the absorbed light power density in comparison with the usual single-layer absorbing capsule. We show that for light-wavelengths-scaled microcapsules it is optimal to use a material with the refractive index larger than two as an outer shell, for example, titanium dioxide (TiO2). The highest values of the absorbed power density can be obtained in microcapsules with absorbing shell thickness of approximately a tenth of a laser wavelength. When laser radiation is scattered by a dimer constituted by two identical absorbing microcapsules the absorbed power density can be maximized by the choosing of proper dimer spatial configuration. In the case of strongly absorbing particles, the absorption maximum corresponds to a shift of the capsules to a distance of about their diameter, and in the case of weakly absorbing particles the absorption is maximal when particles are in geometrical shades of each other.

Imaging at an x-ray absorption edge using free electron laser pulses for interface dynamics in high energy density systems [Resonant phase contrast imaging for interface physics

DOE PAGES

Beckwith, M. A.; Jiang, S.; Schropp, A.; ...

2017-05-01

Tuning the energy of an x-ray probe to an absorption line or edge can provide material-specific measurements that are particularly useful for interfaces. Simulated hard x-ray images above the Fe K-edge are presented to examine ion diffusion across an interface between Fe 2O 3 and SiO 2 aerogel foam materials. The simulations demonstrate the feasibility of such a technique for measurements of density scale lengths near the interface with submicron spatial resolution. A proof-of-principle experiment is designed and performed at the Linac coherent light source facility. Preliminary data show the change of the interface after shock compression and heating withmore » simultaneous fluorescence spectra for temperature determination. Here, the results provide the first demonstration of using x-ray imaging at an absorption edge as a diagnostic to detect ultrafast phenomena for interface physics in high-energy-density systems.« less

Computed Tomography-Based Imaging of Voxel-Wise Lesion Water Uptake in Ischemic Brain: Relationship Between Density and Direct Volumetry.

PubMed

Broocks, Gabriel; Flottmann, Fabian; Ernst, Marielle; Faizy, Tobias Djamsched; Minnerup, Jens; Siemonsen, Susanne; Fiehler, Jens; Kemmling, Andre

2018-04-01

Net water uptake per volume of brain tissue may be calculated by computed tomography (CT) density, and this imaging biomarker has recently been investigated as a predictor of lesion age in acute stroke. However, the hypothesis that measurements of CT density may be used to quantify net water uptake per volume of infarct lesion has not been validated by direct volumetric measurements so far. The purpose of this study was to (1) develop a theoretical relationship between CT density reduction and net water uptake per volume of ischemic lesions and (2) confirm this relationship by quantitative in vitro and in vivo CT image analysis using direct volumetric measurements. We developed a theoretical rationale for a linear relationship between net water uptake per volume of ischemic lesions and CT attenuation. The derived relationship between water uptake and CT density was tested in vitro in a set of increasingly diluted iodine solutions with successive CT measurements. Furthermore, the consistency of this relationship was evaluated using human in vivo CT images in a retrospective multicentric cohort. In 50 edematous infarct lesions, net water uptake was determined by direct measurement of the volumetric difference between the ischemic and normal hemisphere and was correlated with net water uptake calculated by ischemic density measurements. With regard to in vitro data, water uptake by density measurement was equivalent to direct volumetric measurement (r = 0.99, P < 0.0001; mean ± SD difference, -0.29% ± 0.39%, not different from 0, P < 0.0001). In the study cohort, the mean ± SD uptake of water within infarct measured by volumetry was 44.7 ± 26.8 mL and the mean percent water uptake per lesion volume was 22.7% ± 7.4%. This was equivalent to percent water uptake obtained from density measurements: 21.4% ± 6.4%. The mean difference between percent water uptake by direct volumetry and percent water uptake by CT density was -1.79% ± 3.40%, which was not significantly

Density and white shrimp growth pattern (penaeus merguiensis) in kampung nipah waters of perbaungan north sumatera

NASA Astrophysics Data System (ADS)

Natalia Silaen, Sri; Budi Mulya, Miswar

2018-03-01

The purpose of the study was to determine the density and pattern of growth of white shrimp (Penaeus merguiensis)of the village Nipah waters. The data collection was conducted by sampling using nets and fishing gear “Langge” (a tool) to determine the density of the three observation stations. The result showed that the distribution of white shrimp in the waters of the estuary and surrounding degraded over the past ten years. The highest density at station II is 0.56 and 5/m2 and at least at the third station as much as 0.42 and 6/m2 The correlation between the density of shrimp with depth as well as the fraction of the base substrate showed that only the depth of the waters who has any significant correlation with the density of shrimp, although the closeness of the relationship is small.

Laser Atmospheric Absorption Studies.

DTIC Science & Technology

1977-05-01

A. Modification of Commercial C09 Laser 50 B. CW HF/DF Laser System * 53 C. Microcomputer Data Link 55 D . Fourier Transform...improved accuracy are used [5]. c. The absorption coefficient is listed for each absorbing species separately which some codes require. d . A super...series of water vapor absorption measurements was planned. The results of the first four lines studied are presented here in Figures 33a- d . Figure

Food Ingredients That Inhibit Cholesterol Absorption

PubMed Central

Jesch, Elliot D.; Carr, Timothy P.

2017-01-01

Cholesterol is a vital component of the human body. It stabilizes cell membranes and is the precursor of bile acids, vitamin D and steroid hormones. However, cholesterol accumulation in the bloodstream (hypercholesterolemia) can cause atherosclerotic plaques within artery walls, leading to heart attacks and strokes. The efficiency of cholesterol absorption in the small intestine is of great interest because human and animal studies have linked cholesterol absorption with plasma concentration of total and low density lipoprotein cholesterol. Cholesterol absorption is highly regulated and influenced by particular compounds in the food supply. Therefore, it is desirable to learn more about natural food components that inhibit cholesterol absorption so that food ingredients and dietary supplements can be developed for consumers who wish to manage their plasma cholesterol levels by non-pharmacological means. Food components thus far identified as inhibitors of cholesterol absorption include phytosterols, soluble fibers, phospholipids, and stearic acid. PMID:28702423

Performance analysis of single stage libr-water absorption machine operated by waste thermal energy of internal combustion engine: Case study

NASA Astrophysics Data System (ADS)

Sharif, Hafiz Zafar; Leman, A. M.; Muthuraman, S.; Salleh, Mohd Najib Mohd; Zakaria, Supaat

2017-09-01

Combined heating, cooling, and power is also known as Tri-generation. Tri-generation system can provide power, hot water, space heating and air -conditioning from single source of energy. The objective of this study is to propose a method to evaluate the characteristic and performance of a single stage lithium bromide-water (LiBr-H2O) absorption machine operated with waste thermal energy of internal combustion engine which is integral part of trigeneration system. Correlations for computer sensitivity analysis are developed in data fit software for (P-T-X), (H-T-X), saturated liquid (water), saturated vapor, saturation pressure and crystallization temperature curve of LiBr-H2O Solution. Number of equations were developed with data fit software and exported into excel work sheet for the evaluation of number of parameter concerned with the performance of vapor absorption machine such as co-efficient of performance, concentration of solution, mass flow rate, size of heat exchangers of the unit in relation to the generator, condenser, absorber and evaporator temperatures. Size of vapor absorption machine within its crystallization limits for cooling and heating by waste energy recovered from exhaust gas, and jacket water of internal combustion engine also presented in this study to save the time and cost for the facilities managers who are interested to utilize the waste thermal energy of their buildings or premises for heating and air conditioning applications.

Measurements of uranium mass confined in high density plasmas

NASA Technical Reports Server (NTRS)

Stoeffler, R. C.

1976-01-01

An X-ray absorption method for measuring the amount of uranium confined in high density, rf-heated uranium plasmas is described. A comparison of measured absorption of 8 keV X-rays with absorption calculated using Beer Law indicated that the method could be used to measure uranium densities from 3 times 10 to the 16th power atoms/cu cm to 5 times 10 to the 18th power atoms/cu cm. Tests were conducted to measure the density of uranium in an rf-heated argon plasma with UF6 infection and with the power to maintain the discharge supplied by a 1.2 MW rf induction heater facility. The uranium density was measured as the flow rate through the test chamber was varied. A maximum uranium density of 3.85 times 10 to the 17th power atoms/cu cm was measured.

Agnostic stacking of intergalactic doublet absorption: measuring the Ne VIII population

NASA Astrophysics Data System (ADS)

Frank, Stephan; Pieri, Matthew M.; Mathur, Smita; Danforth, Charles W.; Shull, J. Michael

2018-05-01

We present a blind search for doublet intergalactic metal absorption with a method dubbed `agnostic stacking'. Using a forward-modelling framework, we combine this with direct detections in the literature to measure the overall metal population. We apply this novel approach to the search for Ne VIII absorption in a set of 26 high-quality COS spectra. We probe to an unprecedented low limit of log N>12.3 at 0.47≤z ≤1.34 over a path-length Δz = 7.36. This method selects apparent absorption without requiring knowledge of its source. Stacking this mixed population dilutes doublet features in composite spectra in a deterministic manner, allowing us to measure the proportion corresponding to Ne VIII absorption. We stack potential Ne VIII absorption in two regimes: absorption too weak to be significant in direct line studies (12.3 < log N < 13.7), and strong absorbers (log N > 13.7). We do not detect Ne VIII absorption in either regime. Combining our measurements with direct detections, we find that the Ne VIII population is reproduced with a power-law column density distribution function with slope β = -1.86 ^{+0.18 }_{ -0.26} and normalization log f_{13.7} = -13.99 ^{+0.20 }_{ -0.23}, leading to an incidence rate of strong Ne VIII absorbers dn/dz =1.38 ^{+0.97 }_{ -0.82}. We infer a cosmic mass density for Ne VIII gas with 12.3 < log N < 15.0 of Ω _{{{Ne {VIII}}}} = 2.2 ^{+1.6 }_{ _-1.2} × 10^{-8}, a value significantly lower that than predicted by recent simulations. We translate this density into an estimate of the baryon density Ωb ≈ 1.8 × 10-3, constituting 4 per cent of the total baryonic mass.

Intestinal absorption of copper: influence of carbohydrates.

PubMed

Wapnir, R A; Balkman, C

1992-02-01

Macronutrients can modulate the intestinal absorption of trace elements by binding the metal or altering mucosal function. We investigated whether certain simple and complex carbohydrates modify copper (Cu) absorption, using an in vivo perfusion technique in the rat. Corn syrup solids, which contain a mixture of glucose polymers of diverse length, added at either 20 or 50 mosm/kg enhanced Cu absorption from a 31.5 microM (2 mg/liter) Cu solution (128 +/- 11 and 130 +/- 11 pmol/min x cm, respectively, vs 101 +/- 4 pmol/min x cm, P less than 0.05, in the absence of carbohydrate). This was concomitant with a stimulation of net water absorption (1.05 +/- 0.08 and 0.84 +/- 0.08 microliter/min x cm, respectively, vs 0.63 +/- 0.02 microliter/min x cm with no carbohydrate, P less than 0.05). Glucose, fructose, lactose, or sucrose had no influence on Cu absorption, although they altered water exchanges, an effect attributable to a reduction of the outflow component of fluid recirculation. Low concentrations of lactose resulted in a greater accumulation of Cu in the intestinal mucosa (8.75 +/- 0.71 micrograms/g vs 5.77 +/- 0.68 micrograms/g for controls, P less than 0.05). Hence, solutes that moderately stimulate mucosa-to-serosa fluid influx in a progressive manner, such as glucose polymers, may contribute to functionally increase Cu absorption. Conversely, conditions which tend to reduce water inflow or increase water outflow across the small intestinal mucosa, as may occur with high lactose diets or in cases of chronic diarrhea, may have negative effects.

Numerical study on the effects of absorptivity on performance of flat plate solar collector of a water heater

NASA Astrophysics Data System (ADS)

Tambunan, D. R. S.; Sibagariang, Y. P.; Ambarita, H.; Napitupulu, F. H.; Kawai, H.

2018-03-01

The characteristics of absorber plate of a flat plate solar collector play an important role in the improvement of the performance. In this work, a numerical analysis is carried out to explore the effect of absorptivity and emissivity of absorber plate to the performance of the solar collector of a solar water heater. For a results comparison, a simple a simple solar box cooker with absorber area of 0.835 m × 0.835 m is designed and fabricated. It is employed to heat water in a container by exposing to the solar radiation in Medan city of Indonesia. The transient governing equations are developed. The governing equations are discretized and solved using the forward time step marching technique. The results reveal that the experimental and numerical results show good agreement. The absorptivity of the plate absorber and emissivity of the glass cover strongly affect the performance of the solar collector.

Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lam, Royce K.; Smith, Jacob W.; Saykally, Richard J., E-mail: saykally@berkeley.edu

While methanol and ethanol are macroscopically miscible with water, their mixtures exhibit negative excess entropies of mixing. Despite considerable effort in both experiment and theory, there remains significant disagreement regarding the origin of this effect. Different models for the liquid mixture structure have been proposed to address this behavior, including the enhancement of the water hydrogen bonding network around the alcohol hydrophobic groups and microscopic immiscibility or clustering. We have investigated mixtures of methanol, ethanol, and isopropanol with water by liquid microjet X-ray absorption spectroscopy on the oxygen K-edge, an atom-specific probe providing details of both inter- and intra-molecular structure.more » The measured spectra evidence a significant enhancement of hydrogen bonding originating from the methanol and ethanol hydroxyl groups upon the addition of water. These additional hydrogen bonding interactions would strengthen the liquid-liquid interactions, resulting in additional ordering in the liquid structures and leading to a reduction in entropy and a negative enthalpy of mixing, consistent with existing thermodynamic data. In contrast, the spectra of the isopropanol-water mixtures exhibit an increase in the number of broken alcohol hydrogen bonds for mixtures containing up to 0.5 water mole fraction, an observation consistent with existing enthalpy of mixing data, suggesting that the measured negative excess entropy is a result of clustering or micro-immiscibility.« less

High colored dissolved organic matter (CDOM) absorption in surface waters of the central-eastern Arctic Ocean: Implications for biogeochemistry and ocean color algorithms

PubMed Central

Rabe, Benjamin; Peeken, Ilka; Bracher, Astrid

2018-01-01

As consequences of global warming sea-ice shrinking, permafrost thawing and changes in fresh water and terrestrial material export have already been reported in the Arctic environment. These processes impact light penetration and primary production. To reach a better understanding of the current status and to provide accurate forecasts Arctic biogeochemical and physical parameters need to be extensively monitored. In this sense, bio-optical properties are useful to be measured due to the applicability of optical instrumentation to autonomous platforms, including satellites. This study characterizes the non-water absorbers and their coupling to hydrographic conditions in the poorly sampled surface waters of the central and eastern Arctic Ocean. Over the entire sampled area colored dissolved organic matter (CDOM) dominates the light absorption in surface waters. The distribution of CDOM, phytoplankton and non-algal particles absorption reproduces the hydrographic variability in this region of the Arctic Ocean which suggests a subdivision into five major bio-optical provinces: Laptev Sea Shelf, Laptev Sea, Central Arctic/Transpolar Drift, Beaufort Gyre and Eurasian/Nansen Basin. Evaluating ocean color algorithms commonly applied in the Arctic Ocean shows that global and regionally tuned empirical algorithms provide poor chlorophyll-a (Chl-a) estimates. The semi-analytical algorithms Generalized Inherent Optical Property model (GIOP) and Garver-Siegel-Maritorena (GSM), on the other hand, provide robust estimates of Chl-a and absorption of colored matter. Applying GSM with modifications proposed for the western Arctic Ocean produced reliable information on the absorption by colored matter, and specifically by CDOM. These findings highlight that only semi-analytical ocean color algorithms are able to identify with low uncertainty the distribution of the different optical water constituents in these high CDOM absorbing waters. In addition, a clustering of the Arctic Ocean

High colored dissolved organic matter (CDOM) absorption in surface waters of the central-eastern Arctic Ocean: Implications for biogeochemistry and ocean color algorithms.

PubMed

Gonçalves-Araujo, Rafael; Rabe, Benjamin; Peeken, Ilka; Bracher, Astrid

2018-01-01

As consequences of global warming sea-ice shrinking, permafrost thawing and changes in fresh water and terrestrial material export have already been reported in the Arctic environment. These processes impact light penetration and primary production. To reach a better understanding of the current status and to provide accurate forecasts Arctic biogeochemical and physical parameters need to be extensively monitored. In this sense, bio-optical properties are useful to be measured due to the applicability of optical instrumentation to autonomous platforms, including satellites. This study characterizes the non-water absorbers and their coupling to hydrographic conditions in the poorly sampled surface waters of the central and eastern Arctic Ocean. Over the entire sampled area colored dissolved organic matter (CDOM) dominates the light absorption in surface waters. The distribution of CDOM, phytoplankton and non-algal particles absorption reproduces the hydrographic variability in this region of the Arctic Ocean which suggests a subdivision into five major bio-optical provinces: Laptev Sea Shelf, Laptev Sea, Central Arctic/Transpolar Drift, Beaufort Gyre and Eurasian/Nansen Basin. Evaluating ocean color algorithms commonly applied in the Arctic Ocean shows that global and regionally tuned empirical algorithms provide poor chlorophyll-a (Chl-a) estimates. The semi-analytical algorithms Generalized Inherent Optical Property model (GIOP) and Garver-Siegel-Maritorena (GSM), on the other hand, provide robust estimates of Chl-a and absorption of colored matter. Applying GSM with modifications proposed for the western Arctic Ocean produced reliable information on the absorption by colored matter, and specifically by CDOM. These findings highlight that only semi-analytical ocean color algorithms are able to identify with low uncertainty the distribution of the different optical water constituents in these high CDOM absorbing waters. In addition, a clustering of the Arctic Ocean

Assessing the link between chlorophyll concentration and absorption line height at 676 nm over a broad range of water types.

PubMed

Nardelli, Schuyler C; Twardowski, Michael S

2016-10-31

The relationship between absorption at 676 nm normalized to chlorophyll-a, i.e., specific absorption aph*(676), and various optical and environmental properties is examined in extensive data sets from Case I and Case II waters found globally to assess drivers of variability such as pigment packaging. A better understanding of this variability could lead to more accurate estimates of chlorophyll concentrations from in situ optical measurements that may be made autonomously. Values of aph*(676) ranged from 0.00006 to 0.0944 m²/mg Chl a across all sites studied, but converged on median and mean values (n = 563) of 0.0108 and 0.0139 m²/mg Chl a respectively, with no apparent relationship with various optical properties, latitude, coastal or open ocean environment, depth, temperature, salinity, photoadaptation, ecosystem health, or albedo. Relative consistency in aph* across such diverse water types and the full range in chlorophyll concentration suggests a single aph* may be used to estimate chlorophyll concentration from absorption measurements with better accuracy than currently thought.

Evolution of solitary density waves in stellar winds of early-type stars: A simple explanation of discrete absorption component behavior

NASA Technical Reports Server (NTRS)

Waldron, Wayne L.; Klein, Larry; Altner, Bruce

1994-01-01

We model the evolution of a density shell propagating through the stellar wind of an early-type star, in order to investigate the effects of such shells on UV P Cygni line profiles. Unlike previous treatments, we solve the mass, momentum, and energy conservation equations, using an explicit time-differencing scheme, and present a parametric study of the density, velocity, and temperature response. Under the assumed conditions, relatively large spatial scale, large-amplitude density shells propagate as stable waves through the supersonic portion of the wind. Their dynamical behavior appears to mimic propagating 'solitary waves,' and they are found to accelerate at the same rate as the underlying steady state stellar wind (i.e., the shell rides the wind). These hydrodynamically stable structures quantitatively reproduce the anomalous 'discrete absorption component' (DAC) behavior observed in the winds of luminous early-type stars, as illustrated by comparisons of model predictions to an extensive International Ultraviolet Explorer (IUE) time series of spectra of zeta Puppis (O4f). From these comparisons, we find no conclusive evidence indicative of DACs accelerating at a significantly slower rate than the underlying stellar wind, contrary to earlier reports. In addition, these density shells are found to be consistent within the constraints set by the IR observations. We conclude that the concept of propagating density shells should be seriously reconsidered as a possible explanation of the DAC phenomenon in early-type stars.

Supersonic Mass Flux Measurements via Tunable Diode Laser Absorption and Non-Uniform Flow Modeling

NASA Technical Reports Server (NTRS)

Chang, Leyen S.; Strand, Christopher L.; Jeffries, Jay B.; Hanson, Ronald K.; Diskin, Glenn S.; Gaffney, Richard L.; Capriotti, Diego P.

2011-01-01

Measurements of mass flux are obtained in a vitiated supersonic ground test facility using a sensor based on line-of-sight (LOS) diode laser absorption of water vapor. Mass flux is determined from the product of measured velocity and density. The relative Doppler shift of an absorption transition for beams directed upstream and downstream in the flow is used to measure velocity. Temperature is determined from the ratio of absorption signals of two transitions (lambda(sub 1)=1349 nm and lambda(sub 2)=1341.5 nm) and is coupled with a facility pressure measurement to obtain density. The sensor exploits wavelength-modulation spectroscopy with second-harmonic detection (WMS-2f) for large signal-to-noise ratios and normalization with the 1f signal for rejection of non-absorption related transmission fluctuations. The sensor line-of-sight is translated both vertically and horizontally across the test section for spatially-resolved measurements. Time-resolved measurements of mass flux are used to assess the stability of flow conditions produced by the facility. Measurements of mass flux are within 1.5% of the value obtained using a facility predictive code. The distortion of the WMS lineshape caused by boundary layers along the laser line-of-sight is examined and the subsequent effect on the measured velocity is discussed. A method for correcting measured velocities for flow non-uniformities is introduced and application of this correction brings measured velocities within 4 m/s of the predicted value in a 1630 m/s flow.

Effect of various absorption enhancers based on tight junctions on the intestinal absorption of forsythoside A in Shuang-Huang-Lian, application to its antivirus activity

PubMed Central

Zhou, Wei; Zhu, Xuan Xuan; Yin, Ai Ling; Cai, Bao Chang; Wang, Hai Dan; Di, Liuqing; Shan, Jin Jun

2014-01-01

Background: Forsythoside A (FTA), one of the main active ingredients in Shuang–Huang–Lian (SHL), possesses strong antibacterial, antioxidant and antiviral effects, and its pharmacological effects was higher than that of other ingredients, but the absolute bioavailability orally was approximately 0.72%, which was significantly low, influencing clinical efficacies of its oral preparations seriously. Materials and Methods: In vitro Caco-2 cell and in vivo pharmacokinetics study were simultaneously performed to investigate the effects of absorption enhancers based on tight junctions: sodium caprate and water-soluble chitosan on the intestinal absorption of FTA, and the eventual mucosal epithelial damage resulted from absorption enhancers was evaluated by MTT test and morphology observation, respectively. The pharmacological effects such as antivirus activity improvement by absorption enhancers were verified by MDCK damage inhibition rate after influenza virus propagation. Results: The observations from in vitro Caco-2 cell showed that the absorption of FTA in SHL could be improved by absorption enhancers. Meanwhile, the absorption enhancing effect of water-soluble chitosan may be almost saturable up to 0.0032% (w/v), and sodium caprate at concentrations up to 0.64 mg/mL was safe, but water-soluble chitosan at different concentrations was all safe for these cells. In pharmacokinetics study, water-soluble chitosan at dosage of 50 mg/kg improved the bioavailability of FTA in SHL to the greatest extent, and was safe for gastrointestine from morphological observation. Besides, treatment with SHL with water-soluble chitosan at dosage of 50 mg/kg prevented MDCK damage after influenza virus propagation better significantly than that of control. Conclusion: Water-soluble chitosan at dosage of 50 mg/kg might be safe and effective absorption enhancer for improving the bioavailability of FTA and the antivirus activity in vitro in SHL. PMID:24695554

Effect of various absorption enhancers based on tight junctions on the intestinal absorption of forsythoside A in Shuang-Huang-Lian, application to its antivirus activity.

PubMed

Zhou, Wei; Zhu, Xuan Xuan; Yin, Ai Ling; Cai, Bao Chang; Wang, Hai Dan; Di, Liuqing; Shan, Jin Jun

2014-01-01

Forsythoside A (FTA), one of the main active ingredients in Shuang-Huang-Lian (SHL), possesses strong antibacterial, antioxidant and antiviral effects, and its pharmacological effects was higher than that of other ingredients, but the absolute bioavailability orally was approximately 0.72%, which was significantly low, influencing clinical efficacies of its oral preparations seriously. In vitro Caco-2 cell and in vivo pharmacokinetics study were simultaneously performed to investigate the effects of absorption enhancers based on tight junctions: sodium caprate and water-soluble chitosan on the intestinal absorption of FTA, and the eventual mucosal epithelial damage resulted from absorption enhancers was evaluated by MTT test and morphology observation, respectively. The pharmacological effects such as antivirus activity improvement by absorption enhancers were verified by MDCK damage inhibition rate after influenza virus propagation. The observations from in vitro Caco-2 cell showed that the absorption of FTA in SHL could be improved by absorption enhancers. Meanwhile, the absorption enhancing effect of water-soluble chitosan may be almost saturable up to 0.0032% (w/v), and sodium caprate at concentrations up to 0.64 mg/mL was safe, but water-soluble chitosan at different concentrations was all safe for these cells. In pharmacokinetics study, water-soluble chitosan at dosage of 50 mg/kg improved the bioavailability of FTA in SHL to the greatest extent, and was safe for gastrointestine from morphological observation. Besides, treatment with SHL with water-soluble chitosan at dosage of 50 mg/kg prevented MDCK damage after influenza virus propagation better significantly than that of control. Water-soluble chitosan at dosage of 50 mg/kg might be safe and effective absorption enhancer for improving the bioavailability of FTA and the antivirus activity in vitro in SHL.

Density currents in the Chicago River: Characterization, effects on water quality, and potential sources

USGS Publications Warehouse

Jackson, P. Ryan; Garcia, Carlos M.; Oberg, Kevin A.; Johnson, Kevin K.; Garcia, Marcelo H.

2008-01-01

Bidirectional flows in a river system can occur under stratified flow conditions and in addition to creating significant errors in discharge estimates, the upstream propagating currents are capable of transporting contaminants and affecting water quality. Detailed field observations of bidirectional flows were made in the Chicago River in Chicago, Illinois in the winter of 2005-06. Using multiple acoustic Doppler current profilers simultaneously with a water-quality profiler, the formation of upstream propagating density currents within the Chicago River both as an underflow and an overflow was observed on three occasions. Density differences driving the flow primarily arise from salinity differences between intersecting branches of the Chicago River, whereas water temperature is secondary in the creation of these currents. Deicing salts appear to be the primary source of salinity in the North Branch of the Chicago River, entering the waterway through direct runoff and effluent from a wastewater-treatment plant in a large metropolitan area primarily served by combined sewers. Water-quality assessments of the Chicago River may underestimate (or overestimate) the impairment of the river because standard water-quality monitoring practices do not account for density-driven underflows (or overflows). Chloride concentrations near the riverbed can significantly exceed concentrations at the river surface during underflows indicating that full-depth parameter profiles are necessary for accurate water-quality assessments in urban environments where application of deicing salt is common.

A new direct absorption tunable diode laser spectrometer for high precision measurement of water vapor in the upper troposphere and lower stratosphere.

PubMed

Sargent, M R; Sayres, D S; Smith, J B; Witinski, M; Allen, N T; Demusz, J N; Rivero, M; Tuozzolo, C; Anderson, J G

2013-07-01

We present a new instrument for the measurement of water vapor in the upper troposphere and lower stratosphere (UT∕LS), the Harvard Herriott Hygrometer (HHH). HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell. The direct absorption technique provides a direct link between the depth of the observed absorption line and the measured water vapor concentration, which is calculated based on spectroscopic parameters in the HITRAN database. While several other tunable diode laser (TDL) instruments have been used to measure water vapor in the UT∕LS, HHH is set apart by its use of an optical cell an order of magnitude smaller than those of other direct absorption TDLs in operation, allowing for a more compact, lightweight instrument. HHH is also unique in its integration into a common duct with the Harvard Lyman-α hygrometer, an independent photo-fragment fluorescence instrument which has been thoroughly validated over 19 years of flight measurements. The instrument was flown for the first time in the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) on NASA's WB-57 aircraft in spring, 2011, during which it demonstrated in-flight precision of 0.1 ppmv (1 s) with 1-sigma uncertainty of 5% ± 0.7 ppmv. Since the campaign, changes to the instrument have lead to improved accuracy of 5% ± 0.2 ppmv as demonstrated in the laboratory. During MACPEX, HHH successfully measured water vapor at concentrations from 3.5 to 600 ppmv in the upper troposphere and lower stratosphere. HHH and Lyman-α, measuring independently but under the same sampling conditions, agreed on average to within 1% at water vapor mixing ratios above 20 ppmv and to within 0.3 ppmv at lower mixing ratios. HHH also agreed with a number of other in situ water vapor instruments on the WB-57 to within their stated uncertainties, and to within 0.7 ppmv at low water. This agreement constitutes a significant improvement over past in situ comparisons

QPCR Determined Fecal Indicator Bacterial Densities in Marine Waters from Two Recreational Beaches

EPA Science Inventory

The use of real-time qPCR to determine fecal indicator bacteria (FIB) densities is currently being investigated by the U.S. EPA. The present recreational water quality guidelines, based on culturable FIB, prevent same day determinations of water quality whereas results from the ...

Variability of Total and Pathogenic Vibrio parahaemolyticus Densities in Northern Gulf of Mexico Water and Oysters▿

PubMed Central

Zimmerman, A. M.; DePaola, A.; Bowers, J. C.; Krantz, J. A.; Nordstrom, J. L.; Johnson, C. N.; Grimes, D. J.

2007-01-01

Vibrio parahaemolyticus is indigenous to coastal environments and a frequent cause of seafood-borne gastroenteritis in the United States, primarily due to raw-oyster consumption. Previous seasonal-cycle studies of V. parahaemolyticus have identified water temperature as the strongest environmental predictor. Salinity has also been identified, although it is evident that its effect on annual variation is not as pronounced. The effects of other environmental factors, both with respect to the seasonal cycle and intraseasonal variation, are uncertain. This study investigated intraseasonal variations of densities of total and pathogenic V. parahaemolyticus organisms in oysters and overlying waters during the summer of 2004 at two sites in the northern Gulf of Mexico. Regression analyses indicated significant associations (P < 0.001) between total V. parahaemolyticus densities and salinity, as well as turbidity in water and in oysters at the Mississippi site but not at the Alabama site. Pathogenic V. parahaemolyticus organisms in Mississippi oyster and water samples were detected in 56% (9 out of 16) and 78% (43 out of 55) of samples, respectively. In contrast, 44% (7 out of 16) of oyster samples and 30% (14 out of 47) of water samples from Alabama were positive. At both sites, there was greater sample-to-sample variability in pathogenic V. parahaemolyticus densities than in total V. parahaemolyticus densities. These data suggest that, although total V. parahaemolyticus densities may be very informative, there is greater uncertainty when total V. parahaemolyticus densities are used to predict the risk of infection by pathogenic V. parahaemolyticus than previously recognized. PMID:17921270

Variability of total and pathogenic Vibrio parahaemolyticus densities in northern Gulf of Mexico water and oysters.

PubMed

Zimmerman, A M; DePaola, A; Bowers, J C; Krantz, J A; Nordstrom, J L; Johnson, C N; Grimes, D J

2007-12-01

Vibrio parahaemolyticus is indigenous to coastal environments and a frequent cause of seafood-borne gastroenteritis in the United States, primarily due to raw-oyster consumption. Previous seasonal-cycle studies of V. parahaemolyticus have identified water temperature as the strongest environmental predictor. Salinity has also been identified, although it is evident that its effect on annual variation is not as pronounced. The effects of other environmental factors, both with respect to the seasonal cycle and intraseasonal variation, are uncertain. This study investigated intraseasonal variations of densities of total and pathogenic V. parahaemolyticus organisms in oysters and overlying waters during the summer of 2004 at two sites in the northern Gulf of Mexico. Regression analyses indicated significant associations (P < 0.001) between total V. parahaemolyticus densities and salinity, as well as turbidity in water and in oysters at the Mississippi site but not at the Alabama site. Pathogenic V. parahaemolyticus organisms in Mississippi oyster and water samples were detected in 56% (9 out of 16) and 78% (43 out of 55) of samples, respectively. In contrast, 44% (7 out of 16) of oyster samples and 30% (14 out of 47) of water samples from Alabama were positive. At both sites, there was greater sample-to-sample variability in pathogenic V. parahaemolyticus densities than in total V. parahaemolyticus densities. These data suggest that, although total V. parahaemolyticus densities may be very informative, there is greater uncertainty when total V. parahaemolyticus densities are used to predict the risk of infection by pathogenic V. parahaemolyticus than previously recognized.

Water-vapor foreign-continuum absorption in the 8-12 and 3-5 μm atmospheric windows

NASA Astrophysics Data System (ADS)

Klimeshina, T. E.; Rodimova, O. B.

2015-08-01

The frequency and temperature dependence of the water vapor-nitrogen continuum in the 8-12 and 3-5 μm spectral regions obtained experimentally by CAVIAR and NIST is described with the use of the line contour constructed on the basis of asymptotic line shape theory. The parameters of the theory found from fitting the calculated values of the absorption coefficient to the pertinent experimental data enter into the expression for the classical potential describing the center-of-mass motion of interacting molecules and into the expression for the quantum potential of two interacting molecules. The frequency behavior of the line wing contours appears to depend on the band the lines of which make a major contribution to the absorption in a given spectral interval. The absorption coefficients in the wings of the band in question calculated with the line contours obtained for other bands are outside of experimental errors. The distinction in the line wing behavior may be explained by the difference in the quantum energies of molecules interacting in different vibrational states.

Efficient water reduction with gallium phosphide nanowires

PubMed Central

Standing, Anthony; Assali, Simone; Gao, Lu; Verheijen, Marcel A.; van Dam, Dick; Cui, Yingchao; Notten, Peter H. L.; Haverkort, Jos E. M.; Bakkers, Erik P. A. M.

2015-01-01

Photoelectrochemical hydrogen production from solar energy and water offers a clean and sustainable fuel option for the future. Planar III/V material systems have shown the highest efficiencies, but are expensive. By moving to the nanowire regime the demand on material quantity is reduced, and new materials can be uncovered, such as wurtzite gallium phosphide, featuring a direct bandgap. This is one of the few materials combining large solar light absorption and (close to) ideal band-edge positions for full water splitting. Here we report the photoelectrochemical reduction of water, on a p-type wurtzite gallium phosphide nanowire photocathode. By modifying geometry to reduce electrical resistance and enhance optical absorption, and modifying the surface with a multistep platinum deposition, high current densities and open circuit potentials were achieved. Our results demonstrate the capabilities of this material, even when used in such low quantities, as in nanowires. PMID:26183949

The effect of a periodic absorptive strip arrangement on an interior sound field in a room.

PubMed

Park, Joo-Bae; Grosh, Karl; Kim, Yang-Hann

2005-02-01

In this paper we study the effect of periodically arranged sound absorptive strips on the mean acoustic potential energy density distribution of a room. The strips are assumed to be attached on the room's surface of interest. In order to determine their effect, the mean acoustic potential energy density variation is evaluated as the function of a ratio of the strip's arrangement period to wavelength. The evaluation demonstrates that the mean acoustic potential energy density tends to converge. In addition, a comparison with a case in which absorptive materials completely cover the selected absorptive plane shows that a periodic arrangement that uses only half of the absorptive material can be more efficient than a total covering, unless the frequency of interest does not coincide with the room's resonant frequencies. Consequently, the results prove that the ratio of the arrangement period to the wavelength plays an important role in the effectiveness of a periodic absorptive strip arrangement to minimize a room's mean acoustic potential energy density.

High density H2 associative absorption on Titanium alpha-borozene (Ti2B6H6): An ab-initio case study

NASA Astrophysics Data System (ADS)

Akbarzadeh, Alireza; Tymzcak, C. J.

2011-03-01

Hydrogen is considered as a clean energy carrier that could be a future replacement for our addiction to fossil fuels. However, in order to have hydrogen economy at its highest efficiently we need to store hydrogen at high volumetric and gravimetric density. Using the all electron hybrid density functional theory, we have designed a benzene-like-molecule, Ti2B6H6, which has the promise of achieving this goal. Our results show that the molecule can associatively absorb the hydrogen up to ten percent by weight of hydrogen, which exceeds the 2015 US department of energy target. In this presentation we will discuss the mechanisms of H2 absorption and possible applications of this novel molecule. This research is funded by the Welch Foundation under Grant J. 1675 and the Texas Southern University High Performance Computing Center.

Correlation between hardness and water absorption properties of Saudi kaolin and white clay geopolymer coating

NASA Astrophysics Data System (ADS)

Ramasamy, Shamala; Abdullah, Mohd Mustafa Al Bakri; Huang, Yue; Hussin, Kamarudin; Wang, Jin; Shahedan, Noor Fifinatasha

2017-09-01

Geopolymer is an uprising technology that is being studied worldwide. Geopolymer raw materials are basically aluminosilicate source materials. However, this technology is yet to infiltrate into pipelines and coating industries which initiated our research idea. The idea of creating universal geopolymer based coating material is mainly to help oil and gas industry reduce its maintenance cost. Kaolin based geopolymer paste was coated on glass reinforced epoxy (GRE) substrates which are majorly used as pipeline material in the oil and gas industry at Saudi Arabia. Kaolin and white clay was chosen as raw material to study the possibilities of utilizing underused aluminosilicate raw materials for geopolymer coating. To obtain suitable formulation, Na2SiO3/NaOH ratio was varied from 0.40 untill 0.60 while other parameters such as solid/liquid ratio and NaOH molarity were kept constant at values as per previous works. Geopolymer coated GRE substrates were then subjected to water absorption, flexural strength and hardness test to validate our findings. Water absorption is a crucial test as for coating materials which justifies the pratical usability of the coating product. Upon testing, kaolin and white clay based geopolymer coating each shows promising properties at Na2SiO3/NaOH ratio of 0.45 and 0.50 each.

Molecular density functional theory of water describing hydrophobicity at short and long length scales

NASA Astrophysics Data System (ADS)

Jeanmairet, Guillaume; Levesque, Maximilien; Borgis, Daniel

2013-10-01

We present an extension of our recently introduced molecular density functional theory of water [G. Jeanmairet et al., J. Phys. Chem. Lett. 4, 619 (2013)] to the solvation of hydrophobic solutes of various sizes, going from angstroms to nanometers. The theory is based on the quadratic expansion of the excess free energy in terms of two classical density fields: the particle density and the multipolar polarization density. Its implementation requires as input a molecular model of water and three measurable bulk properties, namely, the structure factor and the k-dependent longitudinal and transverse dielectric susceptibilities. The fine three-dimensional water structure around small hydrophobic molecules is found to be well reproduced. In contrast, the computed solvation free-energies appear overestimated and do not exhibit the correct qualitative behavior when the hydrophobic solute is grown in size. These shortcomings are corrected, in the spirit of the Lum-Chandler-Weeks theory, by complementing the functional with a truncated hard-sphere functional acting beyond quadratic order in density, and making the resulting functional compatible with the Van-der-Waals theory of liquid-vapor coexistence at long range. Compared to available molecular simulations, the approach yields reasonable solvation structure and free energy of hard or soft spheres of increasing size, with a correct qualitative transition from a volume-driven to a surface-driven regime at the nanometer scale.

[Absorption Characteristics of Particulates and CDOM in Waters of Chagan Lake and Xinlicheng Reservoir in Autumn].

PubMed

Li, Si-jia; Song, Kai-shan; Zhao, Ying; Mu, Guang-yi; Shao, Tian-tian; Ma, Jian-hang

2016-01-15

Field surveys and laboratory analysis were carried out in Chagan Lake and Xinlicheng Reservoir under different salinity conditions in September 2012. In the laboratory, the absorption coefficients of particulates and chromophoric dissolved organic matter (CDOM) were measured, aiming to compare the absorption features, source of optical active substances and relative contribution of optical active constituents over the range of PAR (400-700 nm) in Chagan Lake and Xinlicheng Reservoir. The results showed that the Chagan Lake and Xinlicheng Reservoir were water bodies with medium eutrophication in autumn by TAL nutrient index and the absorption spectra of particulates matters were similar to those of phytoplankton. For the Chagan Lake with high salinity( EC = 988. 87 micro S x cm(-1)), the total particulate absorption was dominated by the nonalgal particles, and the contribution rate was in the order of nonalgal particles > phytoplankton > CDOM. For the Xinlicheng Reservoir with low salinity (EC = 311.67 microS x -cm(-1)), the total particulate absorption was dominated by the phytoplankton, and the contribution rate was ranked as phytoplankton > nonalgal particles > CDOM. Positive correlation was observed between a(p) (440), a(p) (675), a(d) (440) and total suspended matter (TSM), inorganic suspended matter (ISM), organic suspended matter (OSM) and Chl-a respectively in Chagan Lake, with correlation coefficients all above 0.55. Positive correlation was observed between a(p)(440), a(p) (675) and Chl-a (0.77 and 0.85, P < 0.05) , so did a(d) (440) and ISM (0.74, P < 0.01), while negative correlation was observed between a(p) (440) and OSM in the Xinlicheng Reservoir. In terms of Chagan Lake, negative correlation was merely observed between a(g) (440) and OSM (-0.54, P < 0.05) , but not in the Xinlicheng Reservoir. Both Sg, which was calculated by the fitting absorption curve from 250 to 400 nm, and relative molecular weight M showed that Sg[ (0.021 +/- 0.001) m(-1)] in

Determination of the atomic density of rubidium-87

NASA Astrophysics Data System (ADS)

Zhao, Meng; Zhang, Kai; Chen, Li-Qing

2015-09-01

Atomic density is a basic and important parameter in quantum optics, nonlinear optics, and precision measurement. In the past few decades, several methods have been used to measure atomic density, such as thermionic effect, optical absorption, and resonance fluorescence. The main error of these experiments stemmed from depopulation of the energy level, self-absorption, and the broad bandwidth of the laser. Here we demonstrate the atomic density of 87Rb vapor in paraffin coated cell between 297 K and 334 K mainly using fluorescence measurement. Optical pumping, anti-relaxation coating, and absorption compensation approaches are used to decrease measurement error. These measurement methods are suitable for vapor temperature at dozens of degrees. The fitting function for the experimental data of 87Rb atomic density is given. Project supported by the Natural Science Foundation of China (Grant Nos. 11274118 and 11474095), the Innovation Program of Shanghai Municipal Education Commission of China (Grant No. 13ZZ036), and the Fundamental Research Funds for the Central Universities of China.

Conformational Properties, Spectroscopy and Structure of ISATIN-(WATER)_{n=1-3} Clusters

NASA Astrophysics Data System (ADS)

Singh, Milind K.; Upadhya, D. M.; Singh, Vipin B.

2009-06-01

The structure, stability and vibrational characteristics of Isatin-(Water)_n clusters with n=1=3 have been investigated using second order Moller-Plesset (MP2) perturbation tehory and Density Functional Theory (with B3LYP) methods employing the basis set 6-31+G(d). The vertical excitation energies for these complexes have been also computed using the time-dependent density functional theory. The three stable conformational isomers, each for Isatin-(Water)_1 and Isatin-(Water)_2 clusters were obtained. It is shown that in the most stable isomer of Isatin-(Water)_1 cluster hydrogen bond between amide hydrogen and oxygen of water is found stronger as compared to the H-bond in Indole-(Water)_1 cluster. For a particular position of complexation of water, between the carbonyl oxygen's, results an unusual increase in the dipole moment due to an electronic charge displacement from the N atom to the C atom of the neighboring carbonyl bond. This causes a large separation between the effective charges forming the dipole. The complexes involving this position of water are expected to show a small charge transfer character. The experimentally observed electronic absorption peaks are reasonably reproduced by the TD-DFT calculations and it is found that the longest wavelength absorption peak of isatin at 406 nm is significantly red shifted after addition of a water molecule.

Climate relationships to fecal bacterial densities in Maryland shellfish harvest waters.

PubMed

Leight, A K; Hood, R; Wood, R; Brohawn, K

2016-02-01

Coastal states of the United States (US) routinely monitor shellfish harvest waters for types of bacteria that indicate the potential presence of fecal pollution. The densities of these indicator bacteria in natural waters may be related to climate in several ways, including through runoff from precipitation and survival related to water temperatures. The relationship between interannual precipitation and air temperature patterns and the densities of fecal indicator bacteria in shellfish harvest waters in Maryland's portion of the Chesapeake Bay was quantified using 34 years of data (1979-2013). Annual and seasonal precipitation totals had a strong positive relationship with average fecal coliform levels (R(2) = 0.69) and the proportion of samples with bacterial densities above the FDA regulatory criteria (R(2) = 0.77). Fecal coliform levels were also significantly and negatively related to average annual air temperature (R(2) = -0.43) and the average air temperature of the warmest month (R(2) = -0.57), while average seasonal air temperature was only significantly related to fecal coliform levels in the summer. River and regional fecal coliform levels displayed a wide range of relationships with precipitation and air temperature patterns, with stronger relationships in rural areas and mainstem Bay stations. Fecal coliform levels tended to be higher in years when the bulk of precipitation occurred throughout the summer and/or fall (August to September). Fecal coliform levels often peaked in late fall and winter, with precipitation peaking in summer and early fall. Continental-scale sea level pressure (SLP) analysis revealed an association between atmospheric patterns that influence both extratropical and tropical storm tracks and very high fecal coliform years, while regional precipitation was found to be significantly correlated with the Atlantic Multidecadal Oscillation and the Pacific North American Pattern. These findings indicate that management of

Absolute atomic oxygen density measurements for nanosecond-pulsed atmospheric-pressure plasma jets using two-photon absorption laser-induced fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Jiang, C.; Carter, C.

2014-12-01

Nanosecond-pulsed plasma jets that are generated under ambient air conditions and free from confinement of electrodes have become of great interest in recent years due to their promising applications in medicine and dentistry. Reactive oxygen species that are generated by nanosecond-pulsed, room-temperature non-equilibrium He-O2 plasma jets among others are believed to play an important role during the bactericidal or sterilization processes. We report here absolute measurements of atomic oxygen density in a 1 mm-diameter He/(1%)O2 plasma jet at atmospheric pressure using two-photon absorption laser-induced fluorescence spectroscopy. Oxygen number density on the order of 1013 cm-3 was obtained in a 150 ns, 6 kV single-pulsed plasma jet for an axial distance up to 5 mm above the device nozzle. Temporally resolved O density measurements showed that there are two maxima, separated in time by 60-70 µs, and a total pulse duration of 260-300 µs. Electrostatic modeling indicated that there are high-electric-field regions near the nozzle exit that may be responsible for the observed temporal behavior of the O production. Both the field-distribution-based estimation of the time interval for the O number density profile and a pulse-energy-dependence study confirmed that electric-field-dependent, direct and indirect electron-induced processes play important roles for O production.

Chemical-to-Electricity Carbon: Water Device.

PubMed

He, Sisi; Zhang, Yueyu; Qiu, Longbin; Zhang, Longsheng; Xie, Yun; Pan, Jian; Chen, Peining; Wang, Bingjie; Xu, Xiaojie; Hu, Yajie; Dinh, Cao Thang; De Luna, Phil; Banis, Mohammad Norouzi; Wang, Zhiqiang; Sham, Tsun-Kong; Gong, Xingao; Zhang, Bo; Peng, Huisheng; Sargent, Edward H

2018-05-01

The ability to release, as electrical energy, potential energy stored at the water:carbon interface is attractive, since water is abundant and available. However, many previous reports of such energy converters rely on either flowing water or specially designed ionic aqueous solutions. These requirements restrict practical application, particularly in environments with quiescent water. Here, a carbon-based chemical-to-electricity device that transfers the chemical energy to electrical form when coming into contact with quiescent deionized water is reported. The device is built using carbon nanotube yarns, oxygen content of which is modulated using oxygen plasma-treatment. When immersed in water, the device discharges electricity with a power density that exceeds 700 mW m -2 , one order of magnitude higher than the best previously published result. X-ray absorption and density functional theory studies support a mechanism of operation that relies on the polarization of sp 2 hybridized carbon atoms. The devices are incorporated into a flexible fabric for powering personal electronic devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultraviolet absorption hygrometer

DOEpatents

Gersh, M.E.; Bien, F.; Bernstein, L.S.

1986-12-09

An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined. 5 figs.

Absolute high spectral resolution measurements of surface solar radiation for detection of water vapour continuum absorption.

PubMed

Gardiner, T D; Coleman, M; Browning, H; Tallis, L; Ptashnik, I V; Shine, K P

2012-06-13

Solar-pointing Fourier transform infrared (FTIR) spectroscopy offers the capability to measure both the fine scale and broadband spectral structure of atmospheric transmission simultaneously across wide spectral regions. It is therefore suited to the study of both water vapour monomer and continuum absorption behaviours. However, in order to properly address this issue, it is necessary to radiatively calibrate the FTIR instrument response. A solar-pointing high-resolution FTIR spectrometer was deployed as part of the 'Continuum Absorption by Visible and Infrared radiation and its Atmospheric Relevance' (CAVIAR) consortium project. This paper describes the radiative calibration process using an ultra-high-temperature blackbody and the consideration of the related influence factors. The result is a radiatively calibrated measurement of the solar irradiation at the ground across the IR region from 2000 to 10 000 cm(-1) with an uncertainty of between 3.3 and 5.9 per cent. This measurement is shown to be in good general agreement with a radiative-transfer model. The results from the CAVIAR field measurements are being used in ongoing studies of atmospheric absorbers, in particular the water vapour continuum.

Geometric model from microscopic theory for nuclear absorption

NASA Technical Reports Server (NTRS)

John, Sarah; Townsend, Lawrence W.; Wilson, John W.; Tripathi, Ram K.

1993-01-01

A parameter-free geometric model for nuclear absorption is derived herein from microscopic theory. The expression for the absorption cross section in the eikonal approximation, taken in integral form, is separated into a geometric contribution that is described by an energy-dependent effective radius and two surface terms that cancel in an asymptotic series expansion. For collisions of light nuclei, an expression for the effective radius is derived from harmonic oscillator nuclear density functions. A direct extension to heavy nuclei with Woods-Saxon densities is made by identifying the equivalent half-density radius for the harmonic oscillator functions. Coulomb corrections are incorporated, and a simplified geometric form of the Bradt-Peters type is obtained. Results spanning the energy range from 1 MeV/nucleon to 1 GeV/nucleon are presented. Good agreement with experimental results is obtained.

Geometric model for nuclear absorption from microscopic theory

NASA Technical Reports Server (NTRS)

John, S.; Townsend, L. W.; Wilson, J. W.; Tripathi, R. K.

1993-01-01

A parameter-free geometric model for nuclear absorption is derived from microscopic theory. The expression for the absorption cross section in the eikonal approximation taken in integral form is separated into a geometric contribution, described by an energy-dependent effective radius, and two surface terms which are shown to cancel in an asymptotic series expansion. For collisions of light nuclei, an expression for the effective radius is derived using harmonic-oscillator nuclear density functions. A direct extension to heavy nuclei with Woods-Saxon densities is made by identifying the equivalent half density radius for the harmonic-oscillator functions. Coulomb corrections are incorporated and a simplified geometric form of the Bradt-Peters type obtained. Results spanning the energy range of 1 MeV/nucleon to 1 GeV/nucleon are presented. Good agreement with experimental results are obtained.

[CuCl(n)](2-n) ion-pair species in 1-ethyl-3-methylimidazolium chloride ionic liquid-water mixtures: ultraviolet-visible, X-ray absorption fine structure, and density functional theory characterization.

PubMed

Li, Guosheng; Camaioni, Donald M; Amonette, James E; Zhang, Z Conrad; Johnson, Timothy J; Fulton, John L

2010-10-07

We studied the coordination environment about Cu(II) in a pure ionic liquid, 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl), and in binary mixtures of this compound with water across the entire range of compositions, using a combination of X-ray absorption fine structure (XAFS), ultraviolet-visible (UV-vis) spectroscopy, and electronic structure calculations. Our results show a series of stages in the ion pairing of the divalent cation, Cu(II), including the contact ion pairing of Cu(2+) with multiple Cl(-) ligands to form various CuCl(n)((2-n)) polyanions, as well as the subsequent solvation and ion pairing of the polychlorometallate anion with the EMIM(+) cation. Ion-pair formation is strongly promoted in [EMIM]Cl by the low dielectric constant and by the extensive breakdown of the water hydrogen-bond network in [EMIM]Cl-water mixtures. The CuCl(4)(2-) species dominates in the [EMIM]Cl solvent, and calculations along with spectroscopy show that its geometry distorts to C(2) symmetry compared to D(2d) in the gas phase. These results are important in understanding catalysis and separation processes involving transition metals in ionic liquid systems.

BASIC STUDIES IN PERCUTANEOUS ABSORPTION.

DTIC Science & Technology

FATTY ACIDS, *SKIN(ANATOMY), ABSORPTION, ALKYL RADICALS, AMIDES, DIFFUSION, ELECTRON MICROSCOPY, HUMIDITY, LABORATORY ANIMALS, LIPIDS, ORGANIC SOLVENTS, PENETRATION, PRIVATION, PROTEINS, RATS, TEMPERATURE, WATER

Absorption of a laser light pulse in a dense plasma.

NASA Technical Reports Server (NTRS)

Mehlman-Balloffet, G.

1973-01-01

An experimental study of the absorption of a laser light pulse in a transient, high-density, high-temperature plasma is presented. The plasma is generated around a metallic anode tip by a fast capacitive discharge occurring in vacuum. The amount of transmitted light is measured for plasmas made of different metallic ions in the regions of the discharge of high electronic density. Variation of the transmission during the laser pulse is also recorded. Plasma electrons are considered responsible for the very high absorption observed.

The application of water coupled nonlinear ultrasonics to quantify the dislocation density in aluminum 1100

NASA Astrophysics Data System (ADS)

Mostavi, Amir; Tehrani, N.; Kamali, N.; Ozevin, D.; Chi, S. W.; Indacochea, J. E.

2017-02-01

This article investigates water coupled nonlinear ultrasonic method to measure the dislocation density in aluminum 1100 specimens. The different levels of dislocation densities are introduced to the samples by applying different levels of plastic strains by tensile loading. The ultrasonic testing includes 2.25 MHz transducer as transmitter and 5.0 MHz transducer as receiver in an immersion tank. The results of immersion experiments are compared with oil-coupled experiments. While water has significant nonlinearity within itself, the immersion ultrasound results agree with the literature of oil coupled ultrasound results of the specimens that the nonlinearity coefficient increases with the increase of dislocation density in aluminum.

Vacuum ultraviolet spectroscopy of the lowest-lying electronic state in subcritical and supercritical water

NASA Astrophysics Data System (ADS)

Marin, Timothy W.; Janik, Ireneusz; Bartels, David M.; Chipman, Daniel M.

2017-05-01

The nature and extent of hydrogen bonding in water has been scrutinized for decades, including how it manifests in optical properties. Here we report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of subcritical and supercritical water. For subcritical water, the spectrum redshifts considerably with increasing temperature, demonstrating the gradual breakdown of the hydrogen-bond network. Tuning the density at 381 °C gives insight into the extent of hydrogen bonding in supercritical water. The known gas-phase spectrum, including its vibronic structure, is duplicated in the low-density limit. With increasing density, the spectrum blueshifts and the vibronic structure is quenched as the water monomer becomes electronically perturbed. Fits to the supercritical water spectra demonstrate consistency with dimer/trimer fractions calculated from the water virial equation of state and equilibrium constants. Using the known water dimer interaction potential, we estimate the critical distance between molecules (ca. 4.5 Å) needed to explain the vibronic structure quenching.

Vacuum ultraviolet spectroscopy of the lowest-lying electronic state in subcritical and supercritical water

DOE PAGES

Marin, Timothy W.; Janik, Ireneusz; Bartels, David M.; ...

2017-05-17

The nature and extent of hydrogen bonding in water has been scrutinized for decades, including how it manifests in optical properties. Here we report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of subcritical and supercritical water. For subcritical water, the spectrum redshifts considerably with increasing temperature, demonstrating the gradual breakdown of the hydrogen-bond network. Tuning the density at 381°C gives insight into the extent of hydrogen bonding in supercritical water. The known gas-phase spectrum, including its vibronic structure, is duplicated in the low-density limit. With increasing density, the spectrum blueshifts and the vibronic structure is quenched as themore » water monomer becomes electronically perturbed. Fits to the supercritical water spectra demonstrate consistency with dimer/trimer fractions calculated from the water virial equation of state and equilibrium constants. As a result, using the known water dimer interaction potential, we estimate the critical distance between molecules (ca. 4.5 Å) needed to explain the vibronic structure quenching.« less

Absorption and fluorescence properties of chromophoric dissolved organic matter: implications for the monitoring of water quality in a large subtropical reservoir.

PubMed

Liu, Xiaohan; Zhang, Yunlin; Shi, Kun; Zhu, Guangwei; Xu, Hai; Zhu, Mengyuan

2014-12-01

The development of techniques for real-time monitoring of water quality is of great importance for effectively managing inland water resources. In this study, we first analyzed the absorption and fluorescence properties in a large subtropical reservoir and then used a chromophoric dissolved organic matter (CDOM) fluorescence monitoring sensor to predict several water quality parameters including the total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), dissolved organic carbon (DOC), and CDOM fluorescence parallel factor analysis (PARAFAC) components in the reservoir. The CDOM absorption coefficient at 254 nm (a(254)), the humic-like component (C1), and the tryptophan-like component (C3) decreased significantly along a gradient from the northwest to the lake center, northeast, southwest, and southeast region in the reservoir. However, no significant spatial difference was found for the tyrosine-like component (C2), which contributed only four marked peaks. A highly significant linear correlation was found between the a(254) and CDOM concentration measured using the CDOM fluorescence sensor (r(2) = 0.865, n = 76, p < 0.001), indicating that CDOM concentrations could act as a proxy for the CDOM absorption coefficient measured in the laboratory. Significant correlations were also found between the CDOM concentration and TN, TP, COD, DOC, and the maximum fluorescence intensity of C1, suggesting that the real-time monitoring of CDOM concentrations could be used to predict these water quality parameters and trace the humic-like fluorescence substance in clear aquatic ecosystems with DOC <2 mg/L and total suspended matter (TSM) concentrations <15 mg/L. These results demonstrate that the CDOM fluorescence sensor is a useful tool for on-line water quality monitoring if the empirical relationship between the CDOM concentration measured using the CDOM fluorescence sensor and the water quality parameters is calibrated and validated.

Population density, water supply, and the risk of dengue fever in Vietnam: cohort study and spatial analysis.

PubMed

Schmidt, Wolf-Peter; Suzuki, Motoi; Thiem, Vu Dinh; White, Richard G; Tsuzuki, Ataru; Yoshida, Lay-Myint; Yanai, Hideki; Haque, Ubydul; Tho, Le Huu; Anh, Dang Duc; Ariyoshi, Koya

2011-08-01

Aedes aegypti, the major vector of dengue viruses, often breeds in water storage containers used by households without tap water supply, and occurs in high numbers even in dense urban areas. We analysed the interaction between human population density and lack of tap water as a cause of dengue fever outbreaks with the aim of identifying geographic areas at highest risk. We conducted an individual-level cohort study in a population of 75,000 geo-referenced households in Vietnam over the course of two epidemics, on the basis of dengue hospital admissions (n = 3,013). We applied space-time scan statistics and mathematical models to confirm the findings. We identified a surprisingly narrow range of critical human population densities between around 3,000 to 7,000 people/km² prone to dengue outbreaks. In the study area, this population density was typical of villages and some peri-urban areas. Scan statistics showed that areas with a high population density or adequate water supply did not experience severe outbreaks. The risk of dengue was higher in rural than in urban areas, largely explained by lack of piped water supply, and in human population densities more often falling within the critical range. Mathematical modeling suggests that simple assumptions regarding area-level vector/host ratios may explain the occurrence of outbreaks. Rural areas may contribute at least as much to the dissemination of dengue fever as cities. Improving water supply and vector control in areas with a human population density critical for dengue transmission could increase the efficiency of control efforts. Please see later in the article for the Editors' Summary.

Population Density, Water Supply, and the Risk of Dengue Fever in Vietnam: Cohort Study and Spatial Analysis

PubMed Central

Schmidt, Wolf-Peter; Suzuki, Motoi; Dinh Thiem, Vu; White, Richard G.; Tsuzuki, Ataru; Yoshida, Lay-Myint; Yanai, Hideki; Haque, Ubydul; Huu Tho, Le; Anh, Dang Duc; Ariyoshi, Koya

2011-01-01

Background Aedes aegypti, the major vector of dengue viruses, often breeds in water storage containers used by households without tap water supply, and occurs in high numbers even in dense urban areas. We analysed the interaction between human population density and lack of tap water as a cause of dengue fever outbreaks with the aim of identifying geographic areas at highest risk. Methods and Findings We conducted an individual-level cohort study in a population of 75,000 geo-referenced households in Vietnam over the course of two epidemics, on the basis of dengue hospital admissions (n = 3,013). We applied space-time scan statistics and mathematical models to confirm the findings. We identified a surprisingly narrow range of critical human population densities between around 3,000 to 7,000 people/km2 prone to dengue outbreaks. In the study area, this population density was typical of villages and some peri-urban areas. Scan statistics showed that areas with a high population density or adequate water supply did not experience severe outbreaks. The risk of dengue was higher in rural than in urban areas, largely explained by lack of piped water supply, and in human population densities more often falling within the critical range. Mathematical modeling suggests that simple assumptions regarding area-level vector/host ratios may explain the occurrence of outbreaks. Conclusions Rural areas may contribute at least as much to the dissemination of dengue fever as cities. Improving water supply and vector control in areas with a human population density critical for dengue transmission could increase the efficiency of control efforts. Please see later in the article for the Editors' Summary PMID:21918642

Highly absorptive curcumin reduces serum atherosclerotic low-density lipoprotein levels in patients with mild COPD.

PubMed

Funamoto, Masafumi; Sunagawa, Yoichi; Katanasaka, Yasufumi; Miyazaki, Yusuke; Imaizumi, Atsushi; Kakeya, Hideaki; Yamakage, Hajime; Satoh-Asahara, Noriko; Komiyama, Maki; Wada, Hiromichi; Hasegawa, Koji; Morimoto, Tatsuya

2016-01-01

COPD is mainly caused by tobacco smoking and is associated with a high frequency of coronary artery disease. There is growing recognition that the inflammation in COPD is not only confined to the lungs but also involves the systemic circulation and can impact nonpulmonary organs, including blood vessels. α1-antitrypsin-low-density lipoprotein (AT-LDL) complex is an oxidatively modified LDL that accelerates atherosclerosis. Curcumin, one of the best-investigated natural products, is a powerful antioxidant. However, the effects of curcumin on AT-LDL remain unknown. We hypothesized that Theracurmin(®), a highly absorptive curcumin with improved bioavailability using a drug delivery system, ameliorates the inflammatory status in subjects with mild COPD. This is a randomized, double-blind, parallel-group study. Subjects with stages I-II COPD according to the Japanese Respiratory Society criteria were randomly assigned to receive 90 mg Theracurmin(®) or placebo twice a day for 24 weeks, and changes in inflammatory parameters were evaluated. There were no differences between the Theracurmin(®) and placebo groups in terms of age, male/female ratio, or body mass index in 39 evaluable subjects. The percent changes in blood pressure and hemoglobin A1c and LDL-cholesterol, triglyceride, or high-density lipoprotein-cholesterol levels after treatment were similar for the two groups. However, the percent change in the AT-LDL level was significantly (P=0.020) lower in the Theracurmin(®) group compared with the placebo group. Theracurmin(®) reduced levels of atherosclerotic AT-LDL, which may lead to the prevention of future cardiovascular events in mild COPD subjects.

Controlling coulomb interactions in infrared stereometamaterials for unity light absorption

NASA Astrophysics Data System (ADS)

Mudachathi, Renilkumar; Moritake, Yuto; Tanaka, Takuo

2018-05-01

We investigate the influence of near field interactions between the constituent 3D split ring resonators on the absorbance and resonance frequency of a stereo metamaterial based perfect light absorber. The experimental and theoretical analyses reveal that the magnetic resonance red shifts and broadens for both the decreasing vertical and lateral separations of the constituents within the metamaterial lattice, analogous to plasmon hybridization. The strong interparticle interactions for higher density reduce the effective cross-section per resonator, which results in weak light absorption observed in both experimental and theoretical analyses. The red shift of the magnetic resonance with increasing lattice density is an indication of the dominating electric dipole interactions and we analyzed the metamaterial system in an electrostatic point of view to explain the observed resonance shift and decreasing absorption peak. From these analyses, we found that the fill factor introduces two competing factors determining the absorption efficiency such as coulomb interactions between the constituent resonators and their number density in a given array structure. We predicted unity light absorption for a fill factor of 0.17 balancing these two opposing factors and demonstrate an experimental absorbance of 99.5% at resonance with our 3D device realized using residual stress induced bending of 2D patterns.

Theoretical requirements for broadband perfect absorption of acoustic waves by ultra-thin elastic meta-films

PubMed Central

Duan, Yuetao; Luo, Jie; Wang, Guanghao; Hang, Zhi Hong; Hou, Bo; Li, Jensen; Sheng, Ping; Lai, Yun

2015-01-01

We derive and numerically demonstrate that perfect absorption of elastic waves can be achieved in two types of ultra-thin elastic meta-films: one requires a large value of almost pure imaginary effective mass density and a free space boundary, while the other requires a small value of almost pure imaginary effective modulus and a hard wall boundary. When the pure imaginary density or modulus exhibits certain frequency dispersions, the perfect absorption effect becomes broadband, even in the low frequency regime. Through a model analysis, we find that such almost pure imaginary effective mass density with required dispersion for perfect absorption can be achieved by elastic metamaterials with large damping. Our work provides a feasible approach to realize broadband perfect absorption of elastic waves in ultra-thin films. PMID:26184117

A Multi-Band Analytical Algorithm for Deriving Absorption and Backscattering Coefficients from Remote-Sensing Reflectance of Optically Deep Waters

NASA Technical Reports Server (NTRS)

Lee, Zhong-Ping; Carder, Kendall L.

2001-01-01

A multi-band analytical (MBA) algorithm is developed to retrieve absorption and backscattering coefficients for optically deep waters, which can be applied to data from past and current satellite sensors, as well as data from hyperspectral sensors. This MBA algorithm applies a remote-sensing reflectance model derived from the Radiative Transfer Equation, and values of absorption and backscattering coefficients are analytically calculated from values of remote-sensing reflectance. There are only limited empirical relationships involved in the algorithm, which implies that this MBA algorithm could be applied to a wide dynamic range of waters. Applying the algorithm to a simulated non-"Case 1" data set, which has no relation to the development of the algorithm, the percentage error for the total absorption coefficient at 440 nm a (sub 440) is approximately 12% for a range of 0.012 - 2.1 per meter (approximately 6% for a (sub 440) less than approximately 0.3 per meter), while a traditional band-ratio approach returns a percentage error of approximately 30%. Applying it to a field data set ranging from 0.025 to 2.0 per meter, the result for a (sub 440) is very close to that using a full spectrum optimization technique (9.6% difference). Compared to the optimization approach, the MBA algorithm cuts the computation time dramatically with only a small sacrifice in accuracy, making it suitable for processing large data sets such as satellite images. Significant improvements over empirical algorithms have also been achieved in retrieving the optical properties of optically deep waters.

Size effects of pore density and solute size on water osmosis through nanoporous membrane.

PubMed

Zhao, Kuiwen; Wu, Huiying

2012-11-15

Understanding the behavior of osmotic transport across nanoporous membranes at molecular level is critical to their design and applications, and it is also beneficial to the comprehension of the mechanism of biological transmembrane transport processes. Pore density is an important parameter for nanoporous membranes. To better understand the influence of pore density on osmotic transport, we have performed systematic molecular dynamics simulations on water osmosis across nanoporous membranes with different pore densities (i.e., number of pores per unit area of membrane). The simulation results reveal that significant size effects occur when the pore density is so high that the center-to-center distance between neighboring nanopores is comparable to the solute size. The size effects are independent of the pore diameter and solute concentration. A simple quantitative correlation between pore density, solute size, and osmotic flux has been established. The results are excellently consistent with the theoretical predictions. It is also shown that solute hydration plays an important role in real osmotic processes. Solute hydration strengthens the size effects of pore density on osmotic processes due to the enlarged effective solute size induced by hydration. The influence of pore density, solute size, and solute hydration on water osmosis through nanoporous membranes can be introduced to eliminate the deviations of real osmotic processes from ideal behavior.

Bone Mineral 31P and Matrix-Bound Water Densities Measured by Solid-State 1H and 31P MRI