In situ separation of root hydraulic redistribution of soil water from liquid and vapor transport

Treesearch

Jeffrey M. Warren; J. Renée Brooks; Maria I. Dragila; Frederick C. Meinzer

2011-01-01

Nocturnal increases in water potential and water content in the upper soil profile are often attributed to root water efflux, a process termed hydraulic redistribution (HR). However, unsaturated liquid or vapor flux of water between soil layers independent of roots also contributes to the daily recovery in water content, confounding efforts to determine the actual...

Constraining the Surficial Liquid Water and Resulting Atmospheric Water Vapor Abundance at Recurring Slope Lineae (RSL) Locations on Mars

NASA Astrophysics Data System (ADS)

Berdis, Jodi; Murphy, Jim; Wilson, Robert John

2017-10-01

Possible signatures of atmospheric water vapor arising from Martian Recurring Slope Lineae (RSLs) are investigated in this study. RSLs appear during local spring and summer on downward, equator-facing slopes at southern mid-latitudes (~31-52°S Stillman et al. 2014), and have been linked to liquid water which leaves behind streaks of briny material (McEwen et al. 2011, McEwen et al. 2014). Viking Orbiter Mars Atmospheric Water Detector (VO MAWD) and Mars Global Surveyor Thermal Emission Spectrometer (MGS TES) derived atmospheric water vapor abundance values are interrogated to determine whether four RSL locations at southern mid-latitudes (Palikir Crater, Hale Crater, Horowitz Crater, Coprates Chasma) exhibit episodic, enhanced local atmospheric water vapor abundance during southern spring and summer (Ls = 180-360°) when RSLs are observed to develop (Stillman et al. 2014, Ojha et al. 2015). Significant water vapor signals at these locations might reveal RSLs as the source of the enhanced water vapor. Detected atmospheric water vapor signals would expand upon current knowledge of RSLs, whereas non-detection could provide upper limits on RSL water source content. In order to assess how much surficial RSL water would be required to produce a detectable signal, we utilize the high spatial resolution Geophysical Fluid Dynamics Laboratory Mars Climate General Circulation Model to simulate the evaporation of RSL-producing surface water and quantify the magnitude and temporal duration of water vapor content that might be anticipated in response to inferred RSL surface water release. Finally, we will assess the ability of past and future orbiter-based instruments to detect such water vapor quantities.

The liquid-vapor equilibria of TIP4P/2005 and BLYPSP-4F water models determined through direct simulations of the liquid-vapor interface.

PubMed

Hu, Hongyi; Wang, Feng

2015-06-07

In this paper, the surface tension and critical properties for the TIP4P/2005 and BLYPSP-4F models are reported. A clear dependence of surface tension on the van der Waals cutoff radius (rvdw) is shown when van der Waals interactions are modeled with a simple cutoff scheme. A linear extrapolation formula is proposed that can be used to determine the infinite rvdw surface tension through a few simulations with finite rvdw. A procedure for determining liquid and vapor densities is proposed that does not require fitting to a profile function. Although the critical temperature of water is also found to depend on the choice of rvdw, the dependence is weaker. We argue that a rvdw of 1.75 nm is a good compromise for water simulations when long-range van der Waals correction is not applied. Since the majority of computational programs do not support rigorous treatment of long-range dispersion, the establishment of a minimal acceptable rvdw is important for the simulation of a variety of inhomogeneous systems, such as water bubbles, and water in confined environments. The BLYPSP-4F model predicts room temperature surface tension marginally better than TIP4P/2005 but overestimates the critical temperature. This is expected since only liquid configurations were fit during the development of the BLYPSP-4F potential. The potential is expected to underestimate the stability of vapor and thus overestimate the region of stability for the liquid.

Simulation of water vapor condensation on LOX droplet surface using liquid nitrogen

NASA Technical Reports Server (NTRS)

Powell, Eugene A.

1988-01-01

The formation of ice or water layers on liquid oxygen (LOX) droplets in the Space Shuttle Main Engine (SSME) environment was investigated. Formulation of such ice/water layers is indicated by phase-equilibrium considerations under conditions of high partial pressure of water vapor (steam) and low LOX droplet temperature prevailing in the SSME preburner or main chamber. An experimental investigation was begun using liquid nitrogen as a LOX simulant. A monodisperse liquid nitrogen droplet generator was developed which uses an acoustic driver to force the stream of liquid emerging from a capillary tube to break up into a stream of regularly space uniformly sized spherical droplets. The atmospheric pressure liquid nitrogen in the droplet generator reservoir was cooled below its boiling point to prevent two phase flow from occurring in the capillary tube. An existing steam chamber was modified for injection of liquid nitrogen droplets into atmospheric pressure superheated steam. The droplets were imaged using a stroboscopic video system and a laser shadowgraphy system. Several tests were conducted in which liquid nitrogen droplets were injected into the steam chamber. Under conditions of periodic droplet formation, images of 600 micron diameter liquid nitrogen droplets were obtained with the stroboscopic video systems.

Nimbus 7 SMMR Derived Seasonal Variations in the Water Vapor, Liquid Water and Surface Winds over the Global Oceans

NASA Technical Reports Server (NTRS)

Prabhakara, C.; Short, D. A.

1984-01-01

Monthly mean distributions of water vapor and liquid water contained in a vertical column of the atmosphere and the surface wind speed were derived from Nimbus Scanning Multichannel Microwave Radiometer (SMMR) observations over the global oceans for the period November 1978 to November 1979. The remote sensing techniques used to estimate these parameters from SMMR are presented to reveal the limitations, accuracies, and applicability of the satellite-derived information for climate studies. On a time scale of the order of a month, the distribution of atmospheric water vapor over the oceans is controlled by the sea surface temperature and the large scale atmospheric circulation. The monthly mean distribution of liquid water content in the atmosphere over the oceans closely reflects the precipitation patterns associated with the convectively and baroclinically active regions. Together with the remotely sensed surface wind speed that is causing the sea surface stress, the data collected reveal the manner in which the ocean-atmosphere system is operating. Prominent differences in the water vapor patterns from one year to the next, or from month to month, are associated with anomalies in the wind and geopotential height fields. In association with such circulation anomalies the precipitation patterns deduced from the meteorological network over adjacent continents also reveal anomalous distributions.

Properties of water along the liquid-vapor coexistence curve via molecular dynamics simulations using the polarizable TIP4P-QDP-LJ water model

PubMed Central

Bauer, Brad A.; Patel, Sandeep

2009-01-01

We present an extension of the TIP4P-QDP model, TIP4P-QDP-LJ, that is designed to couple changes in repulsive and dispersive nonbond interactions to changes in polarizability. Polarizability is intimately related to the dispersion component of classical force field models of interactions, and we explore the effect of incorporating this connection explicitly on properties along the liquid-vapor coexistence curve of pure water. Parametrized to reproduce condensed-phase liquid water properties at 298 K, the TIP4P-QDP-LJ model predicts density, enthalpy of vaporization, self-diffusion constant, and the dielectric constant at ambient conditions to about the same accuracy as TIP4P-QDP but shows remarkable improvement in reproducing the liquid-vapor coexistence curve. TIP4P-QDP-LJ predicts critical constants of Tc=623 K, ρc=0.351 g∕cm3, and Pc=250.9 atm, which are in good agreement with experimental values of Tc=647.1 K, ρc=0.322 g∕cm3, and Pc=218 atm, respectively. Applying a scaling factor correction (obtained by fitting the experimental vapor-liquid equilibrium data to the law of rectilinear diameters using a three-term Wegner expansion) the model predicts critical constants (Tc=631 K and ρc=0.308 g∕cm3). Dependence of enthalpy of vaporization, self-diffusion constant, surface tension, and dielectric constant on temperature are shown to reproduce experimental trends. We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied. The interfacial potential demonstrates little temperature dependence at lower temperatures (300–450 K) and significantly enhanced (exponential) dependence at elevated temperatures. Terms arising from the decomposition of the interfacial potential into dipole and quadrupole contributions are shown to monotonically approach zero as the temperature approaches the critical temperature. Results of this study suggest that self-consistently treating the coupling of phase

Properties of water along the liquid-vapor coexistence curve via molecular dynamics simulations using the polarizable TIP4P-QDP-LJ water model.

PubMed

Bauer, Brad A; Patel, Sandeep

2009-08-28

We present an extension of the TIP4P-QDP model, TIP4P-QDP-LJ, that is designed to couple changes in repulsive and dispersive nonbond interactions to changes in polarizability. Polarizability is intimately related to the dispersion component of classical force field models of interactions, and we explore the effect of incorporating this connection explicitly on properties along the liquid-vapor coexistence curve of pure water. Parametrized to reproduce condensed-phase liquid water properties at 298 K, the TIP4P-QDP-LJ model predicts density, enthalpy of vaporization, self-diffusion constant, and the dielectric constant at ambient conditions to about the same accuracy as TIP4P-QDP but shows remarkable improvement in reproducing the liquid-vapor coexistence curve. TIP4P-QDP-LJ predicts critical constants of T(c)=623 K, rho(c)=0.351 g/cm(3), and P(c)=250.9 atm, which are in good agreement with experimental values of T(c)=647.1 K, rho(c)=0.322 g/cm(3), and P(c)=218 atm, respectively. Applying a scaling factor correction (obtained by fitting the experimental vapor-liquid equilibrium data to the law of rectilinear diameters using a three-term Wegner expansion) the model predicts critical constants (T(c)=631 K and rho(c)=0.308 g/cm(3)). Dependence of enthalpy of vaporization, self-diffusion constant, surface tension, and dielectric constant on temperature are shown to reproduce experimental trends. We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied. The interfacial potential demonstrates little temperature dependence at lower temperatures (300-450 K) and significantly enhanced (exponential) dependence at elevated temperatures. Terms arising from the decomposition of the interfacial potential into dipole and quadrupole contributions are shown to monotonically approach zero as the temperature approaches the critical temperature. Results of this study suggest that self-consistently treating the coupling of phase

Isomerization reaction dynamics and equilibrium at the liquid-vapor interface of water. A molecular-dynamics study

NASA Technical Reports Server (NTRS)

Benjamin, Ilan; Pohorille, Andrew

1993-01-01

The gauche-trans isomerization reaction of 1,2-dichloroethane at the liquid-vapor interface of water is studied using molecular-dynamics computer simulations. The solvent bulk and surface effects on the torsional potential of mean force and on barrier recrossing dynamics are computed. The isomerization reaction involves a large change in the electric dipole moment, and as a result the trans/gauche ratio is considerably affected by the transition from the bulk solvent to the surface. Reactive flux correlation function calculations of the reaction rate reveal that deviation from the transition-state theory due to barrier recrossing is greater at the surface than in the bulk water. This suggests that the system exhibits non-Rice-Ramsperger-Kassel-Marcus behavior due to the weak solvent-solute coupling at the water liquid-vapor interface.

Two-channel microwave radiometer for observations of total column precipitable water vapor and cloud liquid water path

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

Liljegren, J.C.

1994-01-01

The Atmospheric Radiation Measurement (ARM) Program is focused on improving the treatment of radiation transfer in models of the atmospheric general circulation, as well as on improving parameterizations of cloud properties and formation processes in these models (USDOE, 1990). To help achieve these objectives, ARM is deploying several two-channel, microwave radiometers at the Cloud and Radiation Testbed (CART) site in Oklahoma for the purpose of obtaining long time series observations of total precipitable water vapor (PWV) and cloud liquid water path (LWP). The performance of the WVR-1100 microwave radiometer deployed by ARM at the Oklahoma CART site central facility tomore » provide time series measurements precipitable water vapor (PWV) and liquid water path (LWP) has been presented. The instrument has proven to be durable and reliable in continuous field operation since June, 1992. The accuracy of the PWV has been demonstrated to achieve the limiting accuracy of the statistical retrieval under clear sky conditions, degrading with increasing LWP. Improvements are planned to address moisture accumulation on the Teflon window, as well as to identity the presence of clouds with LWP at or below the retrieval uncertainty.« less

Water injection into vapor- and liquid-dominated reservoirs: Modeling of heat transfer and mass transport

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

Pruess, K.; Oldenburg, C.; Moridis, G.

1997-12-31

This paper summarizes recent advances in methods for simulating water and tracer injection, and presents illustrative applications to liquid- and vapor-dominated geothermal reservoirs. High-resolution simulations of water injection into heterogeneous, vertical fractures in superheated vapor zones were performed. Injected water was found to move in dendritic patterns, and to experience stronger lateral flow effects than predicted from homogeneous medium models. Higher-order differencing methods were applied to modeling water and tracer injection into liquid-dominated systems. Conventional upstream weighting techniques were shown to be adequate for predicting the migration of thermal fronts, while higher-order methods give far better accuracy for tracer transport.more » A new fluid property module for the TOUGH2 simulator is described which allows a more accurate description of geofluids, and includes mineral dissolution and precipitation effects with associated porosity and permeability change. Comparisons between numerical simulation predictions and data for laboratory and field injection experiments are summarized. Enhanced simulation capabilities include a new linear solver package for TOUGH2, and inverse modeling techniques for automatic history matching and optimization.« less

Remote measurements of ozone, water vapor and liquid water content, and vertical profiles of temperature in the lower troposphere

NASA Technical Reports Server (NTRS)

Grant, W. B.; Gary, B. L.; Shumate, M. S.

1983-01-01

Several advanced atmospheric remote sensing systems developed at the Jet Propulsion Laboratory were demonstrated under various field conditions to determine how useful they would be for general use by the California Air Resources Board and local air quality districts. One of the instruments reported on is the Laser Absorption Spectrometer (LAS). It has a pair of carbon dioxide lasers with a transmitter and receiver and can be flown in an aircraft to measure the column abundance of such gases as ozone. From an aircraft, it can be used to rapidly survey a large region. The LAS is usually operated from an aircraft, although it can also be used at a fixed location on the ground. Some tests were performed with the LAS to measure ozone over a 2-km horizontal path. Another system reported on is the Microwave Atmospheric Remote Sensing System (MARS). It is tuned to microwave emissions from water vapor, liquid water, and oxygen molecules (for atmospheric temperature). It can measure water vapor and liquid water in the line-of-sight, and can measure the vertical temperature profile.

Simulations of the effects of water vapor, cloud liquid water, and ice on AMSU moisture channel brightness temperatures

NASA Technical Reports Server (NTRS)

Muller, Bradley M.; Fuelberg, Henry E.; Xiang, Xuwu

1994-01-01

Radiative transfer simulations are performed to determine how water vapor and nonprecipitating cloud liquid water and ice particles within typical midlatitude atmospheres affect brightness temperatures T(sub B)'s of moisture sounding channels used in the Advanced Microwave Sounding Unit (AMSU) and AMSU-like instruments. The purpose is to promote a general understanding of passive top-of-atmosphere T(sub B)'s for window frequencies at 23.8, 89.0, and 157.0 GHz, and water vapor frequencies at 176.31, 180.31, and 182.31 GHz by documenting specific examples. This is accomplished through detailed analyses of T(sub B)'s for idealized atmospheres, mostly representing temperate conditions over land. Cloud effects are considered in terms of five basic properties: droplet size distribution, phase, liquid or ice water content, altitude, and thickness. Effects on T(sub B) of changing surface emissivity also are addressed. The brightness temperature contribution functions are presented as an aid to physically interpreting AMSU T(sub B)'s. Both liquid and ice clouds impact the T(sub B)'s in a variety of ways. The T(sub B)'s at 23.8 and 89 GHz are more strongly affected by altostratus liquid clouds than by cirrus clouds for equivalent water paths. In contrast, channels near 157 and 183 GHz are more strongly affected by ice clouds. Higher clouds have a greater impact on 157- and 183-GHz T(sub B)'s than do lower clouds. Clouds depress T(sub B)'s of the higher-frequency channels by suppressing, but not necessarily obscuring, radiance contributions from below. Thus, T(sub B)'s are less closely associated with cloud-top temperatures than are IR radiometric temperatures. Water vapor alone accounts for up to 89% of the total attenuation by a midtropospheric liquid cloud for channels near 183 GHz. The Rayleigh approximation is found to be adequate for typical droplet size distributions; however, Mie scattering effects from liquid droplets become important for droplet size distribution

Electrical Breakdown in Water Vapor

NASA Astrophysics Data System (ADS)

Škoro, N.; Marić, D.; Malović, G.; Graham, W. G.; Petrović, Z. Lj.

2011-11-01

In this paper investigations of the voltage required to break down water vapor are reported for the region around the Paschen minimum and to the left of it. In spite of numerous applications of discharges in biomedicine, and recent studies of discharges in water and vapor bubbles and discharges with liquid water electrodes, studies of the basic parameters of breakdown are lacking. Paschen curves have been measured by recording voltages and currents in the low-current Townsend regime and extrapolating them to zero current. The minimum electrical breakdown voltage for water vapor was found to be 480 V at a pressure times electrode distance (pd) value of around 0.6 Torr cm (˜0.8 Pa m). The present measurements are also interpreted using (and add additional insight into) the developing understanding of relevant atomic and particularly surface processes associated with electrical breakdown.

Structure and dynamics of single hydrophobic/ionic heteropolymers at the vapor-liquid interface of water.

PubMed

Vembanur, Srivathsan; Venkateshwaran, Vasudevan; Garde, Shekhar

2014-04-29

We focus on the conformational stability, structure, and dynamics of hydrophobic/charged homopolymers and heteropolymers at the vapor-liquid interface of water using extensive molecular dynamics simulations. Hydrophobic polymers collapse into globular structures in bulk water but unfold and sample a broad range of conformations at the vapor-liquid interface of water. We show that adding a pair of charges to a hydrophobic polymer at the interface can dramatically change its conformations, stabilizing hairpinlike structures, with molecular details depending on the location of the charged pair in the sequence. The translational dynamics of homopolymers and heteropolymers are also different, whereas the homopolymers skate on the interface with low drag, the tendency of charged groups to remain hydrated pulls the heteropolymers toward the liquid side of the interface, thus pinning them, increasing drag, and slowing the translational dynamics. The conformational dynamics of heteropolymers are also slower than that of the homopolymer and depend on the location of the charged groups in the sequence. Conformational dynamics are most restricted for the end-charged heteropolymer and speed up as the charge pair is moved toward the center of the sequence. We rationalize these trends using the fundamental understanding of the effects of the interface on primitive pair-level interactions between two hydrophobic groups and between oppositely charged ions in its vicinity.

Vapor ingestion in Centaur liquid-hydrogen tank

NASA Technical Reports Server (NTRS)

Symons, E. P.

1977-01-01

Vapor ingestion phenomena were investigated using scale models of the Centaur liquid hydrogen tank to determine the height of the free surface of the liquid when vapor is intially ingested into the tank outlet. Data are compared with an analysin and, is general the agreement is very good. Predictions are presented for minimum liquid levels required in the Centaur liquid hydrogen tank in order to prevent vapor ingestion when restarting the engines in space and the quantities of liquid remaining in the tank at vapor ingestion during main engine firing.

Interaction of monovalent ions with the water liquid-vapor interface - A molecular dynamics study

NASA Technical Reports Server (NTRS)

Wilson, Michael A.; Pohorille, Andrew

1991-01-01

Results of molecular dynamics calculations are presented for a series of ions at infinite dilution near the water liquid-vapor interface. The free energies of ion transfer from the bulk to the interface are discussed, as are the accompanying changes of water structure at the surface and ion mobilities as a function of their proximity to the interface. It is shown that simple dielectric models do not provide an accurate description of ions at the water surface. The results of the study should be useful in the development of better models incorporating the shape and molecular structure of the interface.

Intermolecular network analysis of the liquid and vapor interfaces of pentane and water: microsolvation does not trend with interfacial properties.

PubMed

Ghadar, Yasaman; Clark, Aurora E

2014-06-28

Liquid:vapor and liquid:liquid interfaces exhibit complex organizational structure and dynamics at the molecular level. In the case of water and organic solvents, the hydrophobicity of the organic, its conformational flexibility, and compressibility, all influence interfacial properties. This work compares the interfacial tension, width, molecular conformations and orientations at the vapor and aqueous liquid interfaces of two solvents, n-pentane and neopentane, whose varying molecular shapes can lead to significantly different interfacial behavior. Particular emphasis has been dedicated toward understanding how the hydrogen bond network of water responds to the pentane relative to the vapor interface and the sensitivity of the network to the individual pentane isomer and system temperature. Interfacial microsolvation of the immiscible solvents has been examined using graph theoretical methods that quantify the structure and dynamics of microsolvated species (both H2O in C5H12 and C5H12 in H2O). At room temperature, interfacial water at the pentane phase boundary is found to have markedly different organization and dynamics than at the vapor interface (as indicated by the hydrogen bond distributions and hydrogen bond persistence in solution). While the mesoscale interfacial properties (e.g. interfacial tension) are sensitive to the specific pentane isomer, the distribution and persistence of microsolvated species at the interface is nearly identical for both systems, irrespective of temperature (between 273 K and 298 K). This has important implications for understanding how properties defined by the interfacial organization are related to the underlying solvation reactions that drive formation of the phase boundary.

Vapor deposition of water on graphitic surfaces: formation of amorphous ice, bilayer ice, ice I, and liquid water.

PubMed

Lupi, Laura; Kastelowitz, Noah; Molinero, Valeria

2014-11-14

Carbonaceous surfaces are a major source of atmospheric particles and could play an important role in the formation of ice. Here we investigate through molecular simulations the stability, metastability, and molecular pathways of deposition of amorphous ice, bilayer ice, and ice I from water vapor on graphitic and atomless Lennard-Jones surfaces as a function of temperature. We find that bilayer ice is the most stable ice polymorph for small cluster sizes, nevertheless it can grow metastable well above its region of thermodynamic stability. In agreement with experiments, the simulations predict that on increasing temperature the outcome of water deposition is amorphous ice, bilayer ice, ice I, and liquid water. The deposition nucleation of bilayer ice and ice I is preceded by the formation of small liquid clusters, which have two wetting states: bilayer pancake-like (wetting) at small cluster size and droplet-like (non-wetting) at larger cluster size. The wetting state of liquid clusters determines which ice polymorph is nucleated: bilayer ice nucleates from wetting bilayer liquid clusters and ice I from non-wetting liquid clusters. The maximum temperature for nucleation of bilayer ice on flat surfaces, T(B)(max) is given by the maximum temperature for which liquid water clusters reach the equilibrium melting line of bilayer ice as wetting bilayer clusters. Increasing water-surface attraction stabilizes the pancake-like wetting state of liquid clusters leading to larger T(B)(max) for the flat non-hydrogen bonding surfaces of this study. The findings of this study should be of relevance for the understanding of ice formation by deposition mode on carbonaceous atmospheric particles, including soot.

Isotopic composition of water vapor near the air-water interface

NASA Astrophysics Data System (ADS)

Zannoni, Daniele; Bergamasco, Andrea; Peschiutta, Mirco; Rampazzo, Giancarlo; Stenni, Barbara

2017-04-01

Evaporation is a key process in water cycle that links liquid water to the atmosphere. In the last fifty years stable isotopes of hydrogen and oxygen have been intensively used to describe climate processes related to evaporation and precipitation, ranging in different spatial and temporal scales. Evaporation introduces large isotopic effects in the phases involved. The well known Craig-Gordon model (Craig & Gordon, 1965) describes those isotopic effects involving several steps and different processes, moving from the air-water interface to the free atmosphere. However, very few works in literature have tested the vertical behavior of the Craig-Gordon model in natural conditions on both fresh and marine waters. In this work we present the results from four field experiments aimed to describe the vertical variability of δ18O and δD in the first few meters over a large water body (the coastal lagoon of Venice, northern Italy) and to test the Craig-Gordon model in such conditions. Each experiment involved cryotrapping of water vapor at different height over the water surface (0.1m, 2m and 4m) and the sampling of the liquid water at two depth (surface and 0.5m). During the experiments, water vapor was also sampled in the nearest mainland (˜2.5 km from gradient measurements) to determine the isotopic composition of background water vapor. Liquid samples were then analyzed with a Picarro L1102-i and Thermo-Fisher Delta Plus Advantage for water vapor and lagoon water, respectively. The last two experiments have also involved simultaneous measurements of relative humidity using commercially-available humidity probes at each height. This approach was used to determine a reference scale in order to compare observations to modeled estimates. Despite the coarse time resolution due to cryotrapping method (measurements are averaged over 1.5 hours), preliminary results show measurable differences in the isotopic composition of water vapor along the vertical gradient and good

Experimental study of flash boiling spray vaporization through quantitative vapor concentration and liquid temperature measurements

NASA Astrophysics Data System (ADS)

Zhang, Gaoming; Hung, David L. S.; Xu, Min

2014-08-01

Flash boiling sprays of liquid injection under superheated conditions provide the novel solutions of fast vaporization and better air-fuel mixture formation for internal combustion engines. However, the physical mechanisms of flash boiling spray vaporization are more complicated than the droplet surface vaporization due to the unique bubble generation and boiling process inside a superheated bulk liquid, which are not well understood. In this study, the vaporization of flash boiling sprays was investigated experimentally through the quantitative measurements of vapor concentration and liquid temperature. Specifically, the laser-induced exciplex fluorescence technique was applied to distinguish the liquid and vapor distributions. Quantitative vapor concentration was obtained by correlating the intensity of vapor-phase fluorescence with vapor concentration through systematic corrections and calibrations. The intensities of two wavelengths were captured simultaneously from the liquid-phase fluorescence spectra, and their intensity ratios were correlated with liquid temperature. The results show that both liquid and vapor phase of multi-hole sprays collapse toward the centerline of the spray with different mass distributions under the flash boiling conditions. Large amount of vapor aggregates along the centerline of the spray to form a "gas jet" structure, whereas the liquid distributes more uniformly with large vortexes formed in the vicinity of the spray tip. The vaporization process under the flash boiling condition is greatly enhanced due to the intense bubble generation and burst. The liquid temperature measurements show strong temperature variations inside the flash boiling sprays with hot zones present in the "gas jet" structure and vortex region. In addition, high vapor concentration and closed vortex motion seem to have inhibited the heat and mass transfer in these regions. In summary, the vapor concentration and liquid temperature provide detailed information

Vapor-liquid nucleation: the solid touch.

PubMed

Yarom, Michal; Marmur, Abraham

2015-08-01

Vapor-liquid nucleation is a ubiquitous process that has been widely researched in many disciplines. Yet, case studies are quite scattered in the literature, and the implications of some of its basic concepts are not always clearly stated. This is especially noticeable for heterogeneous nucleation, which involves a solid surface in touch with the liquid and vapor. The current review attempts to offer a comprehensive, though concise, thermodynamic discussion of homogeneous and heterogeneous nucleation in vapor-liquid systems. The fundamental concepts of nucleation are detailed, with emphasis on the role of the chemical potential, and on intuitive explanations whenever possible. We review various types of nucleating systems and discuss the effect of the solid geometry on the characteristics of the new phase formation. In addition, we consider the effect of mixing on the vapor-liquid equilibrium. An interesting sub-case is that of a non-volatile solute that modifies the chemical potential of the liquid, but not of the vapor. Finally, we point out topics that need either further research or more exact, accurate presentation. Copyright © 2014 Elsevier B.V. All rights reserved.

MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Datasets

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

KL Gaustad; DD Turner

2007-09-30

This report provides a short description of the Atmospheric Radiation Measurement (ARM) microwave radiometer (MWR) RETrievel (MWRRET) Value-Added Product (VAP) algorithm. This algorithm utilizes complimentary physical and statistical retrieval methods and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

Process for vaporizing a liquid hydrocarbon fuel

DOEpatents

Szydlowski, Donald F.; Kuzminskas, Vaidotas; Bittner, Joseph E.

1981-01-01

The object of the invention is to provide a process for vaporizing liquid hydrocarbon fuels efficiently and without the formation of carbon residue on the apparatus used. The process includes simultaneously passing the liquid fuel and an inert hot gas downwardly through a plurality of vertically spaed apart regions of high surface area packing material. The liquid thinly coats the packing surface, and the sensible heat of the hot gas vaporizes this coating of liquid. Unvaporized liquid passing through one region of packing is uniformly redistributed over the top surface of the next region until all fuel has been vaporized using only the sensible heat of the hot gas stream.

Impact of air and water vapor environments on the hydrophobicity of surfaces.

PubMed

Weisensee, Patricia B; Neelakantan, Nitin K; Suslick, Kenneth S; Jacobi, Anthony M; King, William P

2015-09-01

Droplet wettability and mobility play an important role in dropwise condensation heat transfer. Heat exchangers and heat pipes operate at liquid-vapor saturation. We hypothesize that the wetting behavior of liquid water on microstructures surrounded by pure water vapor differs from that for water droplets in air. The static and dynamic contact angles and contact angle hysteresis of water droplets were measured in air and pure water vapor environments inside a pressure vessel. Pressures ranged from 60 to 1000 mbar, with corresponding saturation temperatures between 36 and 100°C. The wetting behavior was studied on four hydrophobic surfaces: flat Teflon-coated, micropillars, micro-scale meshes, and nanoparticle-coated with hierarchical micro- and nanoscale roughness. Static advancing contact angles are 9° lower in the water vapor environment than in air on a flat surface. One explanation for this reduction in contact angles is water vapor adsorption to the Teflon. On microstructured surfaces, the vapor environment has little effect on the static contact angles. In all cases, variations in pressure and temperature do not influence the wettability and mobility of the water droplets. In most cases, advancing contact angles increase and contact angle hysteresis decreases when the droplets are sliding or rolling down an inclined surface. Copyright © 2015 Elsevier Inc. All rights reserved.

Monolithic microwave integrated circuit water vapor radiometer

NASA Technical Reports Server (NTRS)

Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

1991-01-01

A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

The competition between liquid and vapor transport in transpiring leaves.

PubMed

Rockwell, Fulton Ewing; Holbrook, N Michele; Stroock, Abraham Duncan

2014-04-01

In leaves, the transpirational flux of water exits the veins as liquid and travels toward the stomata in both the vapor and liquid phases before exiting the leaf as vapor. Yet, whether most of the evaporation occurs from the vascular bundles (perivascular), from the photosynthetic mesophyll cells, or within the vicinity of the stomatal pore (peristomatal) remains in dispute. Here, a one-dimensional model of the competition between liquid and vapor transport is developed from the perspective of nonisothermal coupled heat and water molecule transport in a composite medium of airspace and cells. An analytical solution to the model is found in terms of the energy and transpirational fluxes from the leaf surfaces and the absorbed solar energy load, leading to mathematical expressions for the proportions of evaporation accounted for by the vascular, mesophyll, and epidermal regions. The distribution of evaporation in a given leaf is predicted to be variable, changing with the local environment, and to range from dominantly perivascular to dominantly peristomatal depending on internal leaf architecture, with mesophyll evaporation a subordinate component. Using mature red oak (Quercus rubra) trees, we show that the model can be solved for a specific instance of a transpiring leaf by combining gas-exchange data, anatomical measurements, and hydraulic experiments. We also investigate the effect of radiation load on the control of transpiration, the potential for condensation on the inside of an epidermis, and the impact of vapor transport on the hydraulic efficiency of leaf tissue outside the xylem.

Production of a long-term global water vapor and liquid water data set using ultra-fast methods to assimilate multi-satellite and radiosonde observations

NASA Technical Reports Server (NTRS)

Vonderhaar, Thomas H.; Randel, David L.; Reinke, Donald L.; Stephens, Graeme L.; Ringerud, Mark A.; Combs, Cynthia L.; Greenwald, Thomas J.; Wittmeyer, Ian L.

1995-01-01

There is a well-documented requirement for a comprehensive and accurate global moisture data set to assist many important studies in atmospheric science. Currently, atmospheric water vapor measurements are made from a variety of sources including radiosondes, aircraft and surface observations, and in recent years, by various satellite instruments. Creating a global data set from a single measuring system produces results that are useful and accurate only in specific situations and/or areas. Therefore, an accurate global moisture data set has been derived from a combination of these measurement systems. Under a NASA peer-reviewed contract, STC-METSAT produced two 5-yr (1988-1992) global data sets. One is the total column (integrated) water vapor data set and the other, a global layered water vapor data set using a combination of radiosonde observations, Television and Infrared Observation Satellite (TIROS) Operational Satellite (TOVS), and Special Sensor Microwave/Imager (SSM/I) data sets. STC-METSAT also produced a companion, global, integrated liquid water data set. The complete data set (all three products) has been named NVAP, an anachronym for NASA Water Vapor Project. STC-METSAT developed methods to process the data at a daily time scale and 1 x 1 deg spatial resolution.

A new criterion to evaluate water vapor interference in protein secondary structural analysis by FTIR spectroscopy.

PubMed

Zou, Ye; Ma, Gang

2014-06-04

Second derivative and Fourier self-deconvolution (FSD) are two commonly used techniques to resolve the overlapped component peaks from the often featureless amide I band in Fourier transform infrared (FTIR) curve-fitting approach for protein secondary structural analysis. Yet, the reliability of these two techniques is greatly affected by the omnipresent water vapor in the atmosphere. Several criteria are currently in use as quality controls to ensure the protein absorption spectrum is negligibly affected by water vapor interference. In this study, through a second derivative study of liquid water, we first argue that the previously established criteria cannot guarantee a reliable evaluation of water vapor interference due to a phenomenon that we refer to as sample's absorbance-dependent water vapor interference. Then, through a comparative study of protein and liquid water, we show that a protein absorption spectrum can still be significantly affected by water vapor interference even though it satisfies the established criteria. At last, we propose to use the comparison between the second derivative spectra of protein and liquid water as a new criterion to better evaluate water vapor interference for more reliable second derivative and FSD treatments on the protein amide I band.

[Coordination effect between vapor water loss through plant stomata and liquid water supply in soil-plant-atmosphere continuum (SPAC): a review].

PubMed

Liu, Li-Min; Qi, Hua; Luo, Xin-Lan; Zhang, Xuan

2008-09-01

Some important phenomena and behaviors concerned with the coordination effect between vapor water loss through plant stomata and liquid water supply in SPAC were discussed in this paper. A large amount of research results showed that plants show isohydric behavior when the plant hydraulic and chemical signals cooperate to promote the stomatal regulation of leaf water potential. The feedback response of stomata to the change of environmental humidity could be used to explain the midday depression of stomatal conductance and photosynthesis under drought condition, and also, to interpret the correlation between stomatal conductance and hydraulic conductance. The feed-forward response of stomata to the change of environmental humidity could be used to explain the hysteresis response of stomatal conductance to leaf-atmosphere vapor pressure deficit. The strategy for getting the most of xylem transport requires the rapid stomatal responses to avoid excess cavitation and the corresponding mechanisms for reversal of cavitation in short time.

Estimating vapor pressures of pure liquids

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

Haraburda, S.S.

1996-03-01

Calculating the vapor pressures for pure liquid chemicals is a key step in designing equipment for separation of liquid mixtures. Here is a useful way to develop an equation for predicting vapor pressures over a range of temperatures. The technique uses known vapor pressure points for different temperatures. Although a vapor-pressure equation is being showcased in this article, the basic method has much broader applicability -- in fact, users can apply it to develop equations for any temperature-dependent model. The method can be easily adapted for use in software programs for mathematics evaluation, minimizing the need for any programming. Themore » model used is the Antoine equation, which typically provides a good correlation with experimental or measured data.« less

Understanding the liquid-liquid (water-hexane) interface

NASA Astrophysics Data System (ADS)

Murad, Sohail; Puri, Ishwar K.

2017-10-01

Nonequilibrium molecular dynamics simulations are employed to investigate the interfacial thermal resistance of nanoscale hexane-water interfaces subject to an applied heat flux. Our studies show that these liquid-liquid interfaces exhibit behavior significantly dissimilar to that of solid-liquid and solid-vapor interfaces. Notably, the thermal resistance of a hexane-water interface is contingent on the interfacial temperature gradient alone with negligible dependence on the mean interfacial temperature, while the solid-liquid dependent strongly on the interfacial temperature. Application of a heat flux also increases the interface thickness significantly as compared to an equilibrium isothermal interface. Since liquid-liquid interfaces have been proposed for diverse applications, e.g., sensors for wastewater treatment and for extraction of toxic ions from water, they can be designed to be wider by applying a heat flux. This may allow the interface to be used for other applications not possible currently because of the very limited thickness of the interface in isothermal systems.

MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Datasets May 2009

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

Gaustad, KL; Turner, DD

2009-05-30

This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) microwave radiometer (MWR) RETrievel (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

Molecular dynamics study on condensation/evaporation coefficients of chain molecules at liquid-vapor interface

NASA Astrophysics Data System (ADS)

Nagayama, Gyoko; Takematsu, Masaki; Mizuguchi, Hirotaka; Tsuruta, Takaharu

2015-07-01

The structure and thermodynamic properties of the liquid-vapor interface are of fundamental interest for numerous technological implications. For simple molecules, e.g., argon and water, the molecular condensation/evaporation behavior depends strongly on their translational motion and the system temperature. Existing molecular dynamics (MD) results are consistent with the theoretical predictions based on the assumption that the liquid and vapor states in the vicinity of the liquid-vapor interface are isotropic. Additionally, similar molecular condensation/evaporation characteristics have been found for long-chain molecules, e.g., dodecane. It is unclear, however, whether the isotropic assumption is valid and whether the molecular orientation or the chain length of the molecules affects the condensation/evaporation behavior at the liquid-vapor interface. In this study, MD simulations were performed to study the molecular condensation/evaporation behavior of the straight-chain alkanes, i.e., butane, octane, and dodecane, at the liquid-vapor interface, and the effects of the molecular orientation and chain length were investigated in equilibrium systems. The results showed that the condensation/evaporation behavior of chain molecules primarily depends on the molecular translational energy and the surface temperature and is independent of the molecular chain length. Furthermore, the orientation at the liquid-vapor interface was disordered when the surface temperature was sufficiently higher than the triple point and had no significant effect on the molecular condensation/evaporation behavior. The validity of the isotropic assumption was confirmed, and we conclude that the condensation/evaporation coefficients can be predicted by the liquid-to-vapor translational length ratio, even for chain molecules.

Molecular dynamics study on condensation/evaporation coefficients of chain molecules at liquid-vapor interface.

PubMed

Nagayama, Gyoko; Takematsu, Masaki; Mizuguchi, Hirotaka; Tsuruta, Takaharu

2015-07-07

The structure and thermodynamic properties of the liquid-vapor interface are of fundamental interest for numerous technological implications. For simple molecules, e.g., argon and water, the molecular condensation/evaporation behavior depends strongly on their translational motion and the system temperature. Existing molecular dynamics (MD) results are consistent with the theoretical predictions based on the assumption that the liquid and vapor states in the vicinity of the liquid-vapor interface are isotropic. Additionally, similar molecular condensation/evaporation characteristics have been found for long-chain molecules, e.g., dodecane. It is unclear, however, whether the isotropic assumption is valid and whether the molecular orientation or the chain length of the molecules affects the condensation/evaporation behavior at the liquid-vapor interface. In this study, MD simulations were performed to study the molecular condensation/evaporation behavior of the straight-chain alkanes, i.e., butane, octane, and dodecane, at the liquid-vapor interface, and the effects of the molecular orientation and chain length were investigated in equilibrium systems. The results showed that the condensation/evaporation behavior of chain molecules primarily depends on the molecular translational energy and the surface temperature and is independent of the molecular chain length. Furthermore, the orientation at the liquid-vapor interface was disordered when the surface temperature was sufficiently higher than the triple point and had no significant effect on the molecular condensation/evaporation behavior. The validity of the isotropic assumption was confirmed, and we conclude that the condensation/evaporation coefficients can be predicted by the liquid-to-vapor translational length ratio, even for chain molecules.

MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Data Sets (Revision 2)

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

Gaustad, KL; Turner, DD; McFarlane, SA

2011-07-25

This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility microwave radiometer (MWR) Retrieval (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

Large-capacity pump vaporizer for liquid hydrogen and nitrogen

NASA Technical Reports Server (NTRS)

Hauser, J. A.

1970-01-01

Pump vaporizer system delivers 500 standard cubic feet per minute of hydrogen or nitrogen, one system delivers both gases. Vacuum-jacketed pump discharges liquid hydrogen or liquid nitrogen into vaporizing system heated by ambient air. Principal characteristics of the flow and discharge system, pump, and vaporizer are given.

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: III. Vapor-liquid water equilibration of NaCl solutions to 350°C

NASA Astrophysics Data System (ADS)

Horita, Juske; Cole, David R.; Wesolowski, David J.

1995-03-01

The effect of dissolved NaCl on equilibrium oxygen and hydrogen isotope fractionation factors between liquid water and water vapor was precisely determined in the temperature range from 130-350°C, using two different types of apparatus with static or dynamic sampling techniques of the vapor phase. The magnitude of the oxygen and hydrogen isotope effects of NaCl is proportional to the molality of liquid NaCl solutions at a given temperature. Dissolved NaCl lowers appreciably the hydrogen isotope fractionation factor between liquid water and water vapor over the entire temperature range. NaCl has little effect on the oxygen isotope fractionation factor at temperatures below about 200°C, with the magnitude of the salt effect gradually increasing from 200-350°C. Our results are at notable variance with those of Truesdell (1974) and Kazahaya (1986), who reported large oxygen and hydrogen isotope effects of NaCl with very complex dependencies on temperature and NaCl molality. Our high-temperature results have been regressed along with our previous results between 50 and 100°C (Horita et al., 1993a) and the low-temperature literature data to simple equations which are valid for NaCl solutions from 0 to at least 5 molal NaCl in the temperature range from 10-350°C. Our preliminary results of oxygen isotope fractionation in the system CaCO3-water ± NaCl at 300°C and 1 kbar are consistent with those obtained from the liquid-vapor equilibration experiments, suggesting that the isotope salt effects are common to systems involving brines and any other coexisting phases or species (gases, minerals, dissolved species, etc.). The observed NaCl isotope effects at elevated temperatures should be taken into account in the interpretation of isotopic data of brine-dominated natural systems.

Validation of Smithsonian Astrophysical Observatory's OMI Water Vapor Product

NASA Astrophysics Data System (ADS)

Wang, H.; Gonzalez Abad, G.; Liu, X.; Chance, K.

2015-12-01

We perform a comprehensive validation of SAO's OMI water vapor product. The SAO OMI water vapor slant column is retrieved using the 430 - 480 nm wavelength range. In addition to water vapor, the retrieval considers O3, NO2, liquid water, O4, C2H2O2, the Ring effect, water ring, 3rd order polynomial, common mode and under-sampling. The slant column is converted to vertical column using AMF. AMF is calculated using GEOS-Chem water vapor profile shape, OMCLDO2 cloud information and OMLER surface albedo information. We validate our product using NCAR's GPS network data over the world and RSS's gridded microwave data over the ocean. We also compare our product with the total precipitable water derived from the AERONET ground-based sun photometer data, the GlobVapour gridded product, and other datasets. We investigate the influence of sub-grid scale variability and filtering criteria on the comparison. We study the influence of clouds, aerosols and a priori profiles on the retrieval. We also assess the long-term performance and stability of our product and seek ways to improve it.

Correlations between water-soluble organic aerosol and water vapor: a synergistic effect from biogenic emissions?

PubMed

Hennigan, Christopher J; Bergin, Michael H; Weber, Rodney J

2008-12-15

Ground-based measurements of meteorological parameters and water-soluble organic carbon in the gas(WSOCg) and particle (WSOCp) phases were carried out in Atlanta, Georgia, from May to September 2007. Fourteen separate events were observed throughout the summer in which WSOCp and water vapor concentrations were highly correlated (average WSOCp-water vapor r = 0.92); however, for the entire summer, no well-defined relationship existed between the two. The correlation events, which lasted on average 19 h, were characterized by a wide range of WSOCp and water vapor concentrations. Several hypotheses for the correlation are explored, including heterogeneous liquid phase SOA formation and the co-emission of biogenic VOCs and water vapor. The data provide supporting evidence for contributions from both and suggest the possibility of a synergistic effect between the co-emission of water vapor and VOCs from biogenic sources on SOA formation. Median WSOCp concentrations were also correlated with elemental carbon (EC), although this correlation extended over the entire summer. Despite the emission of water vapor from anthropogenic mobile sources and the WSOCp-EC correlation, mobile sources were not considered a potential cause for the WSOCp-water vapor correlations because of their low contribution to the water vapor budget. Meteorology could perhaps have influenced the WSOCp-EC correlation, but other factors are implicated as well. Overall, the results suggest that the temperature-dependent co-emission of water vapor through evapotranspiration and SOA precursor-VOCs by vegetation may be an important process contributing to SOA in some environments.

Development of a liquid-fed water resistojet

NASA Technical Reports Server (NTRS)

Morren, W. Earl; Stone, James R.

1988-01-01

A concept for a forced-flow once-through water vaporizer for application to resistojet thrusters was evaluated as an element of a laboratory model thruster and tested to investigate its operating characteristics. The vaporizer design concept employs flow swirling to attach the liquid flow to the boiler chamber wall, providing for separation of the two liquid phases. This vaporizer was modified with a nozzle and a centrally-located heater to facilitate vaporization, superheating, and expansion of the propellant, allowing it to function as a resistojet. Performance was measured at thrust levels ranging from 170 to 360 mN and at power levels ranging from 443 to 192 W. Maximum measured specific impulse was 192 sec.

Interaction of gases with lunar materials. [surface properties of lunar fines, especially on exposure to water vapor

NASA Technical Reports Server (NTRS)

Holmes, H. F.; Gammage, R. B.

1975-01-01

The surface properties of lunar fines were investigated. Results indicate that, for the most part, these properties are independent of the chemical composition and location of the samples on the lunar surface. The leaching of channels and pores by adsorbed water vapor is a distinguishing feature of their surface chemistry. The elements of air, if adsorbed in conjunction with water vapor or liquid water, severely impedes the leaching process. In the absence of air, liquid water is more effective than water vapor in attacking the grains. The characteristics of Apollo 17 orange fines were evaluated and compared with those of other samples. The interconnecting channels produced by water vapor adsorption were found to be wider than usual for other types of fines. Damage tracks caused by heavy cosmic ray nuclei and an unusually high halogen content might provide for stronger etching conditions upon exposure to water vapor.

Stratospheric water vapor feedback.

PubMed

Dessler, A E; Schoeberl, M R; Wang, T; Davis, S M; Rosenlof, K H

2013-11-05

We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry-climate model to be +0.3 W/(m(2)⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause.

Stratospheric water vapor feedback

PubMed Central

Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

2013-01-01

We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry–climate model to be +0.3 W/(m2⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause. PMID:24082126

Hydrated proton and hydroxide charge transfer at the liquid/vapor interface of water

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

Soniat, Marielle; Rick, Steven W., E-mail: srick@uno.edu; Kumar, Revati

2015-07-28

The role of the solvated excess proton and hydroxide ions in interfacial properties is an interesting scientific question with applications in a variety of aqueous behaviors. The role that charge transfer (CT) plays in interfacial behavior is also an unsettled question. Quantum calculations are carried out on clusters of water with an excess proton or a missing proton (hydroxide) to determine their CT. The quantum results are applied to analysis of multi-state empirical valence bond trajectories. The polyatomic nature of the solvated excess proton and hydroxide ion results in directionally dependent CT, depending on whether a water molecule is amore » hydrogen bond donor or acceptor in relation to the ion. With polyatomic molecules, CT also depends on the intramolecular bond distances in addition to intermolecular distances. The hydrated proton and hydroxide affect water’s liquid/vapor interface in a manner similar to monatomic ions, in that they induce a hydrogen-bonding imbalance at the surface, which results in charged surface waters. This hydrogen bond imbalance, and thus the charged waters at the surface, persists until the ion is at least 10 Å away from the interface.« less

Characterization of the TIP4P-Ew water model: vapor pressure and boiling point.

PubMed

Horn, Hans W; Swope, William C; Pitera, Jed W

2005-11-15

The liquid-vapor-phase equilibrium properties of the previously developed TIP4P-Ew water model have been studied using thermodynamic integration free-energy simulation techniques in the temperature range of 274-400 K. We stress that free-energy results from simulations need to be corrected in order to be compared to the experiment. This is due to the fact that the thermodynamic end states accessible through simulations correspond to fictitious substances (classical rigid liquids and classical rigid ideal gases) while experiments operate on real substances (liquids and real gases, with quantum effects). After applying analytical corrections the vapor pressure curve obtained from simulated free-energy changes is in excellent agreement with the experimental vapor pressure curve. The boiling point of TIP4P-Ew water under ambient pressure is found to be at 370.3+/-1.9 K, about 7 K higher than the boiling point of TIP4P water (363.7+/-5.1 K; from simulations that employ finite range treatment of electrostatic and Lennard-Jones interactions). This is in contrast to the approximately +15 K by which the temperature of the density maximum and the melting temperature of TIP4P-Ew are shifted relative to TIP4P, indicating that the temperature range over which the liquid phase of TIP4P-Ew is stable is narrower than that of TIP4P and resembles more that of real water. The quality of the vapor pressure results highlights the success of TIP4P-Ew in describing the energetic and entropic aspects of intermolecular interactions in liquid water.

Liquid-phase and vapor-phase dehydration of organic/water solutions

DOEpatents

Huang, Yu [Palo Alto, CA; Ly, Jennifer [San Jose, CA; Aldajani, Tiem [San Jose, CA; Baker, Richard W [Palo Alto, CA

2011-08-23

Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

Rate correlation for condensation of pure vapor on turbulent, subcooled liquid

NASA Technical Reports Server (NTRS)

Brown, J. Steven; Khoo, Boo Cheong; Sonin, Ain A.

1990-01-01

An empirical correlation is presented for the condensation of pure vapor on a subcooled, turbulent liquid with a shear-free interface. The correlation expresses the dependence of the condensation rate on fluid properties, on the liquid-side turbulence (which is imposed from below), and on the effects of buoyancy in the interfacial thermal layer. The correlation is derived from experiments with steam and water, but under conditions which simulate typical cryogenic fluids.

G-Band Vapor Radiometer Profiler (GVRP) Handbook

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

Caddeau, MP

2010-06-23

The G-Band Vapor Radiometer Profiler (GVRP) provides time-series measurements of brightness temperatures from 15 channels between 170 and 183.310 GHz. Atmospheric emission in this spectral region is primarily due to water vapor, with some influence from liquid water. Channels between 170.0 and 176.0 GHz are particularly sensitive to the presence of liquid water. The sensitivity to water vapor of the 183.31-GHz line is approximately 30 times higher than at the frequencies of the two-channel microwave radiometer (MWR) for a precipitable water vapor (PWV) amount of less than 2.5 mm. Measurements from the GVRP instrument are therefore especially useful during low-humiditymore » conditions (PWV < 5 mm). In addition to integrated water vapor and liquid water, the GVRP can provide low-resolution vertical profiles of water vapor in very dry conditions.« less

Comparison of vapor formation of water at the solid/water interface to colloidal solutions using optically excited gold nanostructures.

PubMed

Baral, Susil; Green, Andrew J; Livshits, Maksim Y; Govorov, Alexander O; Richardson, Hugh H

2014-02-25

The phase transformation properties of liquid water to vapor is characterized by optical excitation of the lithographically fabricated single gold nanowrenches and contrasted to the phase transformation properties of gold nanoparticles located and optically excited in a bulk solution system [two and three dimensions]. The 532 nm continuous wave excitation of a single gold nanowrench results in superheating of the water to the spinodal decomposition temperature of 580 ± 20 K with bubble formation below the spinodal decomposition temperature being a rare event. Between the spinodal decomposition temperature and the boiling point liquid water is trapped into a metastable state because a barrier to vapor nucleation exists that must be overcome before the thermodynamically stable state is realized. The phase transformation for an optically heated single gold nanowrench is different from the phase transformation of optically excited colloidal gold nanoparticles solution where collective heating effects dominates and leads to the boiling of the solution exactly at the boiling point. In the solution case, the optically excited ensemble of nanoparticles collectively raises the ambient temperature of water to the boiling point where liquid is converted into vapor. The striking difference in the boiling properties of the single gold nanowrench and the nanoparticle solution system can be explained in terms of the vapor-nucleation mechanism, the volume of the overheated liquid, and the collective heating effect. The interpretation of the observed regimes of heating and vaporization is consistent with our theoretical modeling. In particular, we explain with our theory why the boiling with the collective heating in a solution requires 3 orders of magnitude less intensity compared to the case of optically driven single nanowrench.

Compressed liquid densities, saturated liquid densities, and vapor pressures of 1,1-difluoroethane

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

Defibaugh, D.R.; Morrison, G.

1996-05-01

The compressed liquid densities and vapor pressures of 1,1-difluoroethane (HFC-152a) have been measured, correlated, and compared with other data. The liquid densities were measured with a combined standard uncertainty of {+-}0.05% using a vibrating tube densimeter over a temperature range of 243 K to 371 K and at pressures from near the saturated vapor pressure to 6,500 kPa; thus the data extend nearly to the critical point ({Tc} = 386.41 K and P{sub c} = 4514.7 kPa). The vapor pressures were measured with a combined standard uncertainty of {+-}0.02% using a stainless steel ebulliometer in the temperature range from 280more » K to 335 K. Saturated liquid densities were calculated by extrapolating the compressed liquid isotherms to the saturation pressure.« less

The Planck-Benzinger thermal work function in the condensation of water vapor

NASA Astrophysics Data System (ADS)

Chun, Paul W.

Based on the Planck-Benzinger thermal work function using Chun's method, the innate temperature-invariant enthalpy at 0 K, ?H0(T0), for the condensation of water vapor as well as the dimer, trimer, tetramer, and pentamer form in the vapor phase, was determined to be 0.447 kcal mol-1 for vapor, 1.127 for the dimer, 0.555 for the trimer, 0.236 for the tetramer, and 0.079 kcal mol-1 for the pentamer using ?G(T) data reported by Kell et al. in 1968 and Kell and McLaurin in 1969. These results suggest that the predominant dimeric form is the most stable of these n-mers. Using Nemethy and Scheraga's 1962 data for the Helmholtz free energy of liquid water, the value of ?H0(T0) was determined to be 1.21 kcal mol-1. This is very close to the value for the energy of the hydrogen bond EH of 1.32 kcal mol-1 reported by Nemethy and Scheraga, using statistical thermodynamics. It seems clear that very little energy is required for interconversion between the hypothetical supercooled water vapor and glassy water at 0 K. A hypothetical supercooled water vapor at 0 K is apparently almost as highly associated as glassy water at that temperature, suggesting a dynamic equilibrium between vapor and liquid. This water vapor condensation is highly similar in its thermodynamic behavior to that of sequence-specific pairwise (dipeptide) hydrophobic interaction, except that the negative Gibbs free energy change minimum at ?Ts?, the thermal setpoint for vapor condensation, where T?S = 0, occurs at a considerably lower temperature, 270 K (below 0°C) compared with ?350 K. The temperature of condensation ?Tcond? at which ?G(T) = 0, where water vapor begins to condense, was found to be 383 K. In the case of a sequence-specific pairwise hydrophobic interaction, the melting temperature, ?Tm?, where ?G(Tm) = 0 was found to be 460 K. Only between two temperature limits, ?Th? = 99 K and ?Tcond? = 383 K, where ?G(Tcond) = 0, is the net chemical driving force favorable for polymorphism of glassy water

Vapor-Liquid-Solid Etch of Semiconductor Surface Channels by Running Gold Nanodroplets.

PubMed

Nikoobakht, Babak; Herzing, Andrew; Muramoto, Shin; Tersoff, Jerry

2015-12-09

We show that Au nanoparticles spontaneously move across the (001) surface of InP, InAs, and GaP when heated in the presence of water vapor. As they move, the particles etch crystallographically aligned grooves into the surface. We show that this process is a negative analogue of the vapor-liquid-solid (VLS) growth of semiconductor nanowires: the semiconductor dissolves into the catalyst and reacts with water vapor at the catalyst surface to create volatile oxides, depleting the dissolved cations and anions and thus sustaining the dissolution process. This VLS etching process provides a new tool for directed assembly of structures with sublithographic dimensions, as small as a few nanometers in diameter. Au particles above 100 nm in size do not exhibit this process but remain stationary, with oxide accumulating around the particles.

Nonlinear dynamics of confined thin liquid-vapor bilayer systems with phase change

NASA Astrophysics Data System (ADS)

Kanatani, Kentaro; Oron, Alexander

2011-03-01

We numerically investigate the nonlinear evolution of the interface of a thin liquid-vapor bilayer system confined by rigid horizontal walls from both below and above. The lateral variation of the vapor pressure arising from phase change is taken into account in the present analysis. When the liquid (vapor) is heated (cooled) and gravity acts toward the liquid, the deflection of the interface monotonically grows, leading to a rupture of the vapor layer, whereas nonruptured stationary states are found when the liquid (vapor) is cooled (heated) and gravity acts toward the vapor. In the latter case, vapor-flow-driven convective cells are found in the liquid phase in the stationary state. The average vapor pressure and interface temperature deviate from their equilibrium values once the interface departs from the flat equilibrium state. Thermocapillarity does not have a significant effect near the thermodynamic equilibrium, but becomes important if the system significantly deviates from it.

Vapor-liquid phase separator studies

NASA Technical Reports Server (NTRS)

Yuan, S. W. K.; Lee, J. M.; Kim, Y. I.; Hepler, W. A.; Frederking, T. H. K.

1983-01-01

Porous plugs serve as both entropy rejection devices and phase separation components separating the vapor phase on the downstream side from liquid Helium 2 upstream. The liquid upstream is the cryo-reservoir fluid needed for equipment cooling by means of Helium 2, i.e Helium-4 below its lambda temperature in near-saturated states. The topics outlined are characteristic lengths, transport equations and plug results.

SOFIA Water Vapor Monitor Design

NASA Technical Reports Server (NTRS)

Cooper, R.; Roellig, T. L.; Yuen, L.; Shiroyama, B.; Meyer, A.; Devincenzi, D. (Technical Monitor)

2002-01-01

The SOFIA Water Vapor Monitor (WVM) is a heterodyne radiometer designed to determine the integrated amount of water vapor along the telescope line of sight and directly to the zenith. The basic technique that was chosen for the WVM uses radiometric measurements of the center and wings of the 183.3 GHz rotational line of water to measure the water vapor. The WVM reports its measured water vapor levels to the aircraft Mission Controls and Communication System (MCCS) while the SOFIA observatory is in normal operation at flight altitude. The water vapor measurements are also available to other scientific instruments aboard the observatory. The electrical, mechanical and software design of the WVM are discussed.

A search for the prewetting line. [in binary liquid system at vapor-liquid interface

NASA Technical Reports Server (NTRS)

Schmidt, J. W.; Moldover, M. R.

1986-01-01

This paper describes efforts to locate the prewetting line in a binary liquid system (isopropanol-perfluoromethylcyclohexane) at the vapor-liquid interface. Tight upper bounds were placed on the temperature separation (0.2 K) between the prewetting line and the line of bulk liquid phase separation. The prewetting line in systems at equilibrium was not detected. Experimental signatures indicative of the prewetting line occurred only in nonequilibrium situations. Several theories predict that the adsorption of one of the components (the fluorocarbon, in this case) at the liquid-vapor interface should increase abruptly, at a temperature sightly above the temperature at which the mixture separates into two liquid phases. A regular solution calculation indicates that this prewetting line should have been easily detectable with the instruments used in this experiment. Significant features of the experiment are: (1) low-gradient thermostatting, (2) in situ stirring, (3) precision ellipsometry from the vapor-liquid interface, (4) high resolution differential index of refraction measurements using a novel cell design, and (5) computer control.

Vapor-liquid interfacial reaction to fabricate superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabric for oil/water separation

NASA Astrophysics Data System (ADS)

Li, Hongqiang; Liang, Tao; Lai, Xuejun; Su, Xiaojing; Zhang, Lin; Zeng, Xingrong

2018-01-01

With oil spill accidents and oil industrial wastewater increasing, oil/water separation has attracted much attention in recent years. Herein, we report the fabrication of superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabrics for oil/water separation via vapor-liquid interfacial reaction. It is based on sol-gel reaction of tetraethyl orthosilicate (TEOS) to generate silica and thiol-ene reaction between poly(ethylene glycol) dimethacrylate (PEGDMA) and trimethylolpropane tris(3-mercaptopropionate) (TTMP) to form crosslinked hydrophilic polymer on polyester fabric under the catalysis of butylamine/ammonia vapor. The chemical structure of the surfaces on thiol-ene/silica hybrid decorated fabric was confirmed by FTIR and XPS, and obvious micro-nano morphology and roughness were observed with SEM and AFM. The water contact angle of the fabric attained 0° in 0.36 s, and the underwater oil contact angle reached up to 160°. Importantly, the fabric exhibited high separation efficiency at 99.5%, fast water flux above 71600 Lm-2h-1 and excellent recyclability in oil/water separation. Our findings open a new strategy to fabricate organic-inorganic hybrid superhydrophobic and underwater superoleophobic materials for oil/water separation.

The Competition between Liquid and Vapor Transport in Transpiring Leaves1[W][OPEN

PubMed Central

Rockwell, Fulton Ewing; Holbrook, N. Michele; Stroock, Abraham Duncan

2014-01-01

In leaves, the transpirational flux of water exits the veins as liquid and travels toward the stomata in both the vapor and liquid phases before exiting the leaf as vapor. Yet, whether most of the evaporation occurs from the vascular bundles (perivascular), from the photosynthetic mesophyll cells, or within the vicinity of the stomatal pore (peristomatal) remains in dispute. Here, a one-dimensional model of the competition between liquid and vapor transport is developed from the perspective of nonisothermal coupled heat and water molecule transport in a composite medium of airspace and cells. An analytical solution to the model is found in terms of the energy and transpirational fluxes from the leaf surfaces and the absorbed solar energy load, leading to mathematical expressions for the proportions of evaporation accounted for by the vascular, mesophyll, and epidermal regions. The distribution of evaporation in a given leaf is predicted to be variable, changing with the local environment, and to range from dominantly perivascular to dominantly peristomatal depending on internal leaf architecture, with mesophyll evaporation a subordinate component. Using mature red oak (Quercus rubra) trees, we show that the model can be solved for a specific instance of a transpiring leaf by combining gas-exchange data, anatomical measurements, and hydraulic experiments. We also investigate the effect of radiation load on the control of transpiration, the potential for condensation on the inside of an epidermis, and the impact of vapor transport on the hydraulic efficiency of leaf tissue outside the xylem. PMID:24572172

Vapor-Liquid Equilibria of Imidazolium Ionic Liquids with Cyano Containing Anions with Water and Ethanol.

PubMed

Khan, Imran; Batista, Marta L S; Carvalho, Pedro J; Santos, Luís M N B F; Gomes, José R B; Coutinho, João A P

2015-08-13

Isobaric vapor-liquid equilibria of 1-butyl-3-methylimidazolium thiocyanate ([C4C1im][SCN]), 1-butyl-3-methylimidazolium dicyanamide ([C4C1im][N(CN)2]), 1-butyl-3-methylimidazolium tricyanomethanide ([C4C1im][C(CN)3]), and 1-ethyl-3-methylimidazolium tetracyanoborate ([C2C1im][B(CN)4]), with water and ethanol were measured over the whole concentration range at 0.1, 0.07, and 0.05 MPa. Activity coefficients were estimated from the boiling temperatures of the binary systems, and the data were used to evaluate the ability of COSMO-RS for describing these molecular systems. Aiming at further understanding the molecular interactions on these systems, molecular dynamics (MD) simulations were performed. On the basis of the interpretation of the radial and spatial distribution functions along with coordination numbers obtained through MD simulations, the effect of the increase of CN-groups in the IL anion in its capability to establish hydrogen bonds with water and ethanol was evaluated. The results obtained suggest that, for both water and ethanol systems, the anion [N(CN)2](-) presents the higher ability to establish favorable interactions due to its charge, and that the ability of the anions to interact with the solvent, decreases with further increasing of the number of cyano groups in the anion. The ordering of the partial charges in the nitrogen atoms from the CN-groups in the anions agrees with the ordering obtained for VLE and activity coefficient data.

Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point

ERIC Educational Resources Information Center

Tellinghuisen, Joel

2010-01-01

Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

Numerical simulation of superheated vapor bubble rising in stagnant liquid

NASA Astrophysics Data System (ADS)

Samkhaniani, N.; Ansari, M. R.

2017-09-01

In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

Liquid-Vapor Equilibrium of Multicomponent Cryogenic Systems

NASA Technical Reports Server (NTRS)

Thompson, W. Reid; Calado, Jorge C. G.; Zollweg, John A.

1990-01-01

Liquid-vapor and solid-vapor equilibria at low to moderate pressures and low temperatures are important in many solar system environments, including the surface and clouds of Titan, the clouds of Uranus and Neptune, and the surfaces of Mars and Triton. The familiar cases of ideal behavior are limiting cases of a general thermodynamic representation for the vapor pressure of each component in a homogeneous multicomponent system. The fundamental connections of laboratory measurements to thermodynamic models are through the Gibbs-Duhem relation and the Gibbs-Helmholtz relation. Using laboratory measurements of the total pressure, temperature, and compositions of the liquid and vapor phases at equilibrium, the values of these parameters can be determined. The resulting model for vapor-liquid equilibrium can then conveniently and accurately be used to calculate pressures, compositions, condensation altitudes, and their dependencies on changing climatic conditions. A specific system being investigated is CH4-C2H6-N2, at conditions relevant to Titan's surface and atmosphere. Discussed are: the modeling of existing data on CH4-N2, with applications to the composition of Titan's condensate clouds; some new measurements on the CH4-C2H6 binary, using a high-precision static/volumetric system, and on the C2H6-N2 binary, using the volumetric system and a sensitive cryogenic flow calorimeter; and describe a new cryogenic phase-equilibrium vessel with which we are beginning a detailed, systematic study of the three constituent binaries and the ternary CH4-C2H6-N2 system at temperatures ranging from 80 to 105 K and pressures from 0.1 to 7 bar.

Trends of total water vapor column above the Arctic from satellites observations

NASA Astrophysics Data System (ADS)

Alraddawi, Dunya; Sarkissian, Alain; Keckhut, Philippe; Bock, Olivier; Claud, Chantal; Irbah, Abdenour

2016-04-01

Atmospheric water vapor (H2O) is the most important natural (as opposed to man-made) greenhouse gas, accounting for about two-thirds of the natural greenhouse effect. Despite this importance, its role in climate and its reaction to climate change are still difficult to assess. Many details of the hydrological cycle are poorly understood, such as the process of cloud formation and the transport and release of latent heat contained in the water vapor. In contrast to other important greenhouse gases like carbon dioxide (CO2) and methane, water vapor has a much higher temporal and spatial variability. Total precipitable water (TPW) or the total column of water vapor (TCWV) is the amount of liquid water that would result if all the water vapor in the atmospheric column of unit area were condensed. TCWV distribution contains valuable information on the vigor of the hydrological processes and moisture transport in the atmosphere. Measurement of TPW can be obtained based on atmospheric water vapor absorption or emission of radiation in the spectral range from UV to MW. TRENDS were found over the terrestrial Arctic by means of TCWV retrievals (using Moderate Resolution Imaging Spectro-radiometer (MODIS) near-infrared (2001-2015) records). More detailed approach was made for comparisons with ground based instruments over Sodankyla - Finland (TCWV from: SCIAMACHY 2003-2011, GOME-2A 2007-2011, SAOZ 2003-2011, GPS 2003-2011, MODIS 2003-2011)

Vapor-Enabled Propulsion for Plasmonic Photothermal Motor at the Liquid/Air Interface.

PubMed

Meng, Fanchen; Hao, Wei; Yu, Shengtao; Feng, Rui; Liu, Yanming; Yu, Fan; Tao, Peng; Shang, Wen; Wu, Jianbo; Song, Chengyi; Deng, Tao

2017-09-13

This paper explores a new propulsion mechanism that is based on the ejection of hot vapor jet to propel the motor at the liquid/air interface. For conventional photothermal motors, which mostly are driven by Marangoni effect, it is challenging to propel those motors at the surfaces of liquids with low surface tension due to the reduced Marangoni effect. With this new vapor-enabled propulsion mechanism, the motors can move rapidly at the liquid/air interface of liquids with a broad range of surface tensions. A design that can accumulate the hot vapor is further demonstrated to enhance both the propulsion force as well as the applicable range of liquids for such motors. This new propulsion mechanism will help open up new opportunities for the photothermal motors with desired motion controls at a wide range of liquid/air interfaces where hot vapor can be generated.

Retrieving Liquid Water Path and Precipitable Water Vapor from the Atmospheric Radiation Measurement (ARM) Microwave Radiometers

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

Turner, David D.; Clough, Shepard A.; Liljegren, James C.

2007-11-01

Ground-based two-channel microwave radiometers have been used for over 15 years by the Atmospheric Radiation Measurement (ARM) program to provide observations of downwelling emitted radiance from which precipitable water vapor (PWV) and liquid water path (LWP) – twp geophysical parameters critical for many areas of atmospheric research – are retrieved. An algorithm that utilizes two advanced retrieval techniques, a computationally expensive physical-iterative approach and an efficient statistical method, has been developed to retrieve these parameters. An important component of this Microwave Retrieval (MWRRET) algorithm is the determination of small (< 1K) offsets that are subtracted from the observed brightness temperaturesmore » before the retrievals are performed. Accounting for these offsets removes systematic biases from the observations and/or the model spectroscopy necessary for the retrieval, significantly reducing the systematic biases in the retrieved LWP. The MWRRET algorithm provides significantly more accurate retrievals than the original ARM statistical retrieval which uses monthly retrieval coefficients. By combining the two retrieval methods with the application of brightness temperature offsets to reduce the spurious LWP bias in clear skies, the MWRRET algorithm provides significantly better retrievals of PWV and LWP from the ARM 2-channel microwave radiometers compared to the original ARM product.« less

The influence of liquid/vapor phase change onto the Nusselt number

NASA Astrophysics Data System (ADS)

Popescu, Elena-Roxana; Colin, Catherine; Tanguy, Sebastien

2017-11-01

In spite of its significant interest in various fields, there is currently a very few information on how an external flow will modify the evaporation or the condensation of a liquid surface. Although most applications involve turbulent flows, the simpler configuration where a laminar superheated or subcooled vapor flow is shearing a saturated liquid interface has still never been solved. Based on a numerical approach, we propose to characterize the interaction between a laminar boundary layer of a superheated or subcooled vapor flow and a static liquid pool at saturation temperature. By performing a full set of simulations sweeping the parameters space, correlations are proposed for the first time on the Nusselt number depending on the dimensionless numbers that characterize both vaporization and condensation. As attended, the Nusselt number decreases or increases in the configurations involving respectively vaporization or condensation. More unexpected is the behaviour of the friction of the vapor flow on the liquid pool, for which we report that it is weakly affected by the phase change, despite the important variation of the local flow structure due to evaporation or condensation.

Vacuum distillation: vapor filtered-catalytic oxidation water reclamation system utilizing radioisotopes

NASA Technical Reports Server (NTRS)

Honegger, R. J.; Remus, G. A.; Kurg, E. K.

1971-01-01

The development of a functional model water reclamation system is discussed. The system produces potable water by distillation from the urine and respiration-perspiration condensate at the normal rate generated by four men. Basic processes employed are vacuum distillation, vapor filtration, vapor phase catalytic oxidation, and condensation. The system is designed to use four 75-watt isotope heaters for distillation thermal input, and one 45-watt isotope for the catalytic oxidation unit. The system is capable of collecting and storing urine, and provides for stabilizing the urine by chemical pretreatment. The functional model system is designed for operation in a weightless condition with liquid-vapor phase separators for the evaporator still, and centrifugal separators for urine collection and vapor condensation. The system provides for storing and dispensing reclaimed potable water. The system operates in a batch mode for 40 days, with urine residues accumulating in the evaporator. The evaporator still and residue are removed to storage and replaced with a fresh still for the next 40-day period.

Effect of the Thermocouple on Measuring the Temperature Discontinuity at a Liquid-Vapor Interface.

PubMed

Kazemi, Mohammad Amin; Nobes, David S; Elliott, Janet A W

2017-07-18

The coupled heat and mass transfer that occurs in evaporation is of interest in a large number of fields such as evaporative cooling, distillation, drying, coating, printing, crystallization, welding, atmospheric processes, and pool fires. The temperature jump that occurs at an evaporating interface is of central importance to understanding this complex process. Over the past three decades, thermocouples have been widely used to measure the interfacial temperature jumps at a liquid-vapor interface during evaporation. However, the reliability of these measurements has not been investigated so far. In this study, a numerical simulation of a thermocouple when it measures the interfacial temperatures at a liquid-vapor interface is conducted to understand the possible effects of the thermocouple on the measured temperature and features in the temperature profile. The differential equations of heat transfer in the solid and fluids as well as the momentum transfer in the fluids are coupled together and solved numerically subject to appropriate boundary conditions between the solid and fluids. The results of the numerical simulation showed that while thermocouples can measure the interfacial temperatures in the liquid correctly, they fail to read the actual interfacial temperatures in the vapor. As the results of our numerical study suggest, the temperature jumps at a liquid-vapor interface measured experimentally by using a thermocouple are larger than what really exists at the interface. For a typical experimental study of evaporation of water at low pressure, it was found that the temperature jumps measured by a thermocouple are overestimated by almost 50%. However, the revised temperature jumps are still in agreement with the statistical rate theory of interfacial transport. As well as addressing the specific application of the liquid-vapor temperature jump, this paper provides significant insight into the role that heat transfer plays in the operation of thermocouples

Assessment of Atmospheric Water Vapor Abundance Above RSL Locations on Mars

NASA Astrophysics Data System (ADS)

Berdis, Jodi R.; Murphy, Jim; Wilson, Robert John

2016-10-01

The possible signatures of atmospheric water vapor arising from Martian Recurring Slope Lineae (RSLs)1 are investigated. These RSLs appear during local spring and summer on downward slopes, and have been linked to liquid water which leaves behind streaks of briny material. Viking Orbiter Mars Atmospheric Water Detector (MAWD)2 and Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES)3-5 derived water vapor abundance values are interrogated to determine whether four RSL locations at southern mid-latitudes (Palikir Crater, Hale Crater, Horowitz Crater, and Coprates Chasma) exhibit episodic enhanced local water vapor abundance during southern summer solstice (Ls = 270°) and autumnal equinox (Ls = 360°) when RSLs are observed to develop6,7. Any detected atmospheric water vapor signal would expand upon current knowledge of RSLs, while non-detection would provide upper limits on RSL water content. Viking Orbiter Infrared Thermal Mapper (IRTM) and MGS TES derived temperature values are also investigated due to the appearance of active RSLs after the surface temperature of the slopes exceeds 250 K1.A high spatial resolution Martian atmospheric numerical model will be employed to assess the magnitude and temporal duration of water vapor content that might be anticipated in response to inferred RSL surface water release. The ability of past and future orbiter-based instruments to detect such water vapor quantities will be assessed.References1. McEwen, A. et al. 2011, Sci., 333, 7402. Jakosky, B. & Farmer, C. 1982, JGR, 87, 29993. Christensen, P. et al. 1992, JGR, 97, 77194. Christensen, P. et al. 2001, JGR, 106, 238235. Smith, M. 2002, JGR, 107, 51156. Ojha, L. et al. 2015, Nature Geosci., 8, 8297. Stillman, D. et al. 2014, Icarus, 233, 328

Water Vapor Feedbacks to Climate Change

NASA Technical Reports Server (NTRS)

Rind, David

1999-01-01

The response of water vapor to climate change is investigated through a series of model studies with varying latitudinal temperature gradients, mean temperatures, and ultimately, actual climate change configurations. Questions to be addressed include: what role does varying convection have in water vapor feedback; do Hadley Circulation differences result in differences in water vapor in the upper troposphere; and, does increased eddy energy result in greater eddy vertical transport of water vapor in varying climate regimes?

Evaluation of soil water stable isotope analysis by H2O(liquid)-H2O(vapor) equilibration method

NASA Astrophysics Data System (ADS)

Gralher, Benjamin; Stumpp, Christine

2014-05-01

Environmental tracers like stable isotopes of water (δ18O, δ2H) have proven to be valuable tools to study water flow and transport processes in soils. Recently, a new technique for soil water isotope analysis has been developed that employs a vapor phase being in isothermal equilibrium with the liquid phase of interest. This has increased the potential application of water stable isotopes in unsaturated zone studies as it supersedes laborious extraction of soil water. However, uncertainties of analysis and influencing factors need to be considered. Therefore, the objective of this study was to evaluate different methodologies of analysing stable isotopes in soil water in order to reduce measurement uncertainty. The methodologies included different preparation procedures of soil cores for equilibration of vapor and soil water as well as raw data correction. Two different inflatable sample containers (freezer bags, bags containing a metal layer) and equilibration atmospheres (N2, dry air) were tested. The results showed that uncertainties for δ18O were higher compared to δ2H that cannot be attributed to any specific detail of the processing routine. Particularly, soil samples with high contents of organic matter showed an apparent isotope enrichment which is indicative for fractionation due to evaporation. However, comparison of water samples obtained from suction cups with the local meteoric water line indicated negligible fractionation processes in the investigated soils. Therefore, a method was developed to correct the raw data reducing the uncertainties of the analysis.. We conclude that the evaluated method is advantageous over traditional methods regarding simplicity, resource requirements and sample throughput but careful consideration needs to be made regarding sample handling and data processing. Thus, stable isotopes of water are still a good tool to determine water flow and transport processes in the unsaturated zone.

Liquid-vapor rectilinear diameter revisited

NASA Astrophysics Data System (ADS)

Garrabos, Y.; Lecoutre, C.; Marre, S.; Beysens, D.; Hahn, I.

2018-02-01

In the modern theory of critical phenomena, the liquid-vapor density diameter in simple fluids is generally expected to deviate from a rectilinear law approaching the critical point. However, by performing precise scannerlike optical measurements of the position of the SF6 liquid-vapor meniscus, in an approach much closer to criticality in temperature and density than earlier measurements, no deviation from a rectilinear diameter can be detected. The observed meniscus position from far (10 K ) to extremely close (1 mK ) to the critical temperature is analyzed using recent theoretical models to predict the complete scaling consequences of a fluid asymmetry. The temperature dependence of the meniscus position appears consistent with the law of rectilinear diameter. The apparent absence of the critical hook in SF6 therefore seemingly rules out the need for the pressure scaling field contribution in the complete scaling theoretical framework in this SF6 analysis. More generally, this work suggests a way to clarify the experimental ambiguities in the simple fluids for the near-critical singularities in the density diameter.

Liquid-Desiccant Vapor Separation Reduces the Energy Requirements of Atmospheric Moisture Harvesting.

PubMed

Gido, Ben; Friedler, Eran; Broday, David M

2016-08-02

An innovative atmospheric moisture harvesting system is proposed, where water vapor is separated from the air prior to cooling and condensation. The system was studied using a model that simulates its three interconnected cycles (air, desiccant, and water) over a range of ambient conditions, and optimal configurations are reported for different operation conditions. Model results were compared to specifications of commercial atmospheric moisture harvesting systems and found to represent saving of 5-65% of the electrical energy requirements due to the vapor separation process. We show that the liquid desiccant separation stage that is integrated into atmospheric moisture harvesting systems can work under a wide range of environmental conditions using low grade or solar heating as a supplementary energy source, and that the performance of the combined system is superior.

Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics study

NASA Technical Reports Server (NTRS)

Wilson, M. A.; Pohorille, A.

1997-01-01

The free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.

Comparison of cryopreserved human sperm in vapor and liquid phases of liquid nitrogen: effect on motility parameters, morphology, and sperm function.

PubMed

Punyatanasakchai, Piyaphan; Sophonsritsuk, Areephan; Weerakiet, Sawaek; Wansumrit, Surapee; Chompurat, Deonthip

2008-11-01

To compare the effects of cryopreserved sperm in vapor and liquid phases of liquid nitrogen on sperm motility, morphology, and sperm function. Experimental study. Andrology laboratory at Ramathibodi Hospital, Thailand. Thirty-eight semen samples with normal motility and sperm count were collected from 38 men who were either patients of an infertility clinic or had donated sperm for research. Each semen sample was divided into two aliquots. Samples were frozen with static-phase vapor cooling. One aliquot was plunged into liquid nitrogen (-196 degrees C), and the other was stored in vapor-phase nitrogen (-179 degrees C) for 3 days. Thawing was performed at room temperature. Motility was determined by using computer-assisted semen analysis, sperm morphology was determined by using eosin-methylene blue staining, and sperm function was determined by using a hemizona binding test. Most of the motility parameters of sperm stored in the vapor phase were not significantly different from those stored in the liquid phase of liquid nitrogen, except in amplitude of lateral head displacement. The percentages of normal sperm morphology in both vapor and liquid phases also were not significantly different. There was no significant difference in the number of bound sperm in hemizona between sperm cryopreserved in both vapor and liquid phases of liquid nitrogen. Cryopreservation of human sperm in a vapor phase of liquid nitrogen was comparable to cryopreservation in a liquid phase of liquid nitrogen.

21 CFR 868.1975 - Water vapor analyzer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Water vapor analyzer. 868.1975 Section 868.1975...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1975 Water vapor analyzer. (a) Identification. A water vapor analyzer is a device intended to measure the concentration of water vapor in a...

21 CFR 868.1975 - Water vapor analyzer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Water vapor analyzer. 868.1975 Section 868.1975...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1975 Water vapor analyzer. (a) Identification. A water vapor analyzer is a device intended to measure the concentration of water vapor in a...

21 CFR 868.1975 - Water vapor analyzer.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Water vapor analyzer. 868.1975 Section 868.1975...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1975 Water vapor analyzer. (a) Identification. A water vapor analyzer is a device intended to measure the concentration of water vapor in a...

21 CFR 868.1975 - Water vapor analyzer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Water vapor analyzer. 868.1975 Section 868.1975...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1975 Water vapor analyzer. (a) Identification. A water vapor analyzer is a device intended to measure the concentration of water vapor in a...

21 CFR 868.1975 - Water vapor analyzer.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Water vapor analyzer. 868.1975 Section 868.1975...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1975 Water vapor analyzer. (a) Identification. A water vapor analyzer is a device intended to measure the concentration of water vapor in a...

Effects of water vapor on flue gas conditioning in the electric fields with corona discharge.

PubMed

Liqiang, Qi; Yajuan, Zhang

2013-07-15

Sulfur dioxide (SO2) removal via pulsed discharge nonthermal plasma in the absence of ammonia was investigated to determine how electrostatic precipitators (ESPs) can effectively collect particulate matter less than 2.5μm in diameter from flue gas. SO2 removal increased as water vapor concentration increased. In a wet-type plasma reactor, directing a gas-phase discharge plasma toward the water film surface significantly enhanced the liquid-phase oxidation of HSO3(-) to SO4(2-). Comparisons of various absorbents revealed that the hydroxyl radical is a key factor in plasma-induced liquid-phase reactions. The resistivity, size distribution, and cohesive force of fly ash at different water vapor contents were measured using a Bahco centrifuge, which is a dust electrical resistivity test instrument, as well as a cohesive force test apparatus developed by the researchers. When water vapor content increased by 5%, fly ash resistivity in flue gas decreased by approximately two orders of magnitude, adhesive force and size increased, and specific surface area decreased. Therefore, ESP efficiency increased. Copyright © 2013 Elsevier B.V. All rights reserved.

Universal adsorption at the vapor-liquid interface near the consolute point

NASA Technical Reports Server (NTRS)

Schmidt, James W.

1990-01-01

The ellipticity of the vapor-liquid interface above mixtures of methylcyclohexane (C7H14) and perfluoromethylcyclohexane (C7F14) has been measured near the consolute point T(c) = 318.6 K. The data are consistent with a model of the interface that combines a short-ranged density-vs height profile in the vapor phase with a much longer-ranged composition-versus-height profile in the liquid. The value of the free parameter produced by fitting the model to the data is consistent with results from two other simple mixtures and a mixture of a polymer and solvent. This experiment combines precision ellipsometry of the vapor-liquid interface with in situ measurements of refractive indices of the liquid phases, and it precisely locates the consolute point.

Stable isotopic variations of water vapor on the winter coastal area in Korea

NASA Astrophysics Data System (ADS)

Lee, Jeonghoon; Lee, Songyi; Han, Yeongcheol; Do Hur, Soon

2017-04-01

Studies of isotopic compositions of precipitation in Korea have been conducted for groundwater mixing and sources and residence time of water. Unravelling of water vapor isotopes will be very helpful in explaining the sources of moisture. In this work, we first present isotopic compositions of water vapor over western part of Korea in winter between December 2015 and February 2016. We collected the samples of water vapor isotopes by a cryogenic method with impingers and liquid nitrogen. We captured the water vapor for 4 to 6 hours, depending on humidity and collected 54 samples in total. The samples were analyzed by a Picarro L2130-i and the precisions were 0.06‰ and 0.7‰ for oxygen and hydrogen, respectively. The isotopic compositions of water vapor ranged from -34.04‰ to -15.27‰ for oxygen and from -221.9‰ to -100.2‰ for hydrogen. The deuterium excess (d=δD-8*δ18O) was between 17.4 and 44.0 in permil. Both air temperature (T, δ18O=0.57*T-25.5, R2=0.46) and relative humidity (RH, δ18O=0.18*RH-35.9, R2=0.38) were positively correlated with the water vapor isotopes. This is not consistent with the fact that precipitation isotopes are correlated with only temperate in winter Eastern Asia. We expect that the water vapor isotopes will be an important role to understand the origin and pathway of moistures over the Eastern Asia.

Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation & Condensation at a Liquid/Vapor Interface

NASA Technical Reports Server (NTRS)

Stewart, Mark E. M.

2017-01-01

This paper presents an analysis and simulation of evaporation and condensation at a motionless liquid/vapor interface. A 1-D model equation, emphasizing heat and mass transfer at the interface, is solved in two ways, and incorporated into a subgrid interface model within a CFD simulation. Simulation predictions are compared with experimental data from the CPST Engineering Design Unit tank, a cryogenic fluid management test tank in 1-g. The numerical challenge here is the physics of the liquid/vapor interface; pressurizing the ullage heats it by several degrees, and sets up an interfacial temperature gradient that transfers heat to the liquid phase-the rate limiting step of condensation is heat conducted through the liquid and vapor. This physics occurs in thin thermal layers O(1 mm) on either side of the interface which is resolved by the subgrid interface model. An accommodation coefficient of 1.0 is used in the simulations which is consistent with theory and measurements. This model is predictive of evaporation/condensation rates, that is, there is no parameter tuning.

Liquid fuel vaporizer and combustion chamber having an adjustable thermal conductor

DOEpatents

Powell, Michael R; Whyatt, Greg A; Howe, Daniel T; Fountain, Matthew S

2014-03-04

The efficiency and effectiveness of apparatuses for vaporizing and combusting liquid fuel can be improved using thermal conductors. For example, an apparatus having a liquid fuel vaporizer and a combustion chamber can be characterized by a thermal conductor that conducts heat from the combustion chamber to the vaporizer. The thermal conductor can be a movable member positioned at an insertion depth within the combustion chamber that corresponds to a rate of heat conduction from the combustion chamber to the vaporizer. The rate of heat conduction can, therefore, be adjusted by positioning the movable member at a different insertion depth.

Structure and energetics of model amphiphilic molecules at the water liquid-vapor interface - A molecular dynamics study

NASA Technical Reports Server (NTRS)

Pohorille, Andrew; Benjamin, Ilan

1993-01-01

A molecular dynamics study of adsorption of p-n-pentylphenol at infinite dilution at the water liquid-vapor interface is reported. The calculated free energy of adsorption is -8.8 +/- 0.7 kcal/mol, in good agreement with the experimental value of -7.3 kcal/mol. The transition between the interfacial region and the bulk solution is sharp and well-defined by energetic, conformational, and orientational criteria. At the water surface, the phenol head group is mostly immersed in aqueous solvent. The most frequent orientation of the hydrocarbon tail is parallel to the interface, due to dispersion interactions with the water surface. This arrangement of the phenol ring and the alkyl chain requires that the chain exhibits a kink. As the polar head group is being moved into the solvent, the chain length increases and the tail becomes increasingly aligned toward the surface normal, such that the nonpolar part of the molecule exposed to water is minimized. The same effect was achieved when phenol was replaced by a more polar head group, phenolate.

Liquid Water in the Extremely Shallow Martian Subsurface

NASA Technical Reports Server (NTRS)

Pavlov, A.; Shivak, J. N.

2012-01-01

Availability of liquid water is one of the major constraints for the potential Martian biosphere. Although liquid water is unstable on the surface of Mars due to low atmospheric pressures, it has been suggested that liquid films of water could be present in the Martian soil. Here we explored a possibility of the liquid water formation in the extremely shallow (1-3 cm) subsurface layer under low atmospheric pressures (0.1-10 mbar) and low ("Martian") surface temperatures (approx.-50 C-0 C). We used a new Goddard Martian simulation chamber to demonstrate that even in the clean frozen soil with temperatures as low as -25C the amount of mobile water can reach several percents. We also showed that during brief periods of simulated daylight warming the shallow subsurface ice sublimates, the water vapor diffuses through porous surface layer of soil temporarily producing supersaturated conditions in the soil, which leads to the formation of additional liquid water. Our results suggest that despite cold temperatures and low atmospheric pressures, Martian soil just several cm below the surface can be habitable.

Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds

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

Westwater, Edgeworth

2011-05-06

The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently lessmore » than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third

Water vapor distribution in protoplanetary disks

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

Du, Fujun; Bergin, Edwin A., E-mail: fdu@umich.edu

Water vapor has been detected in protoplanetary disks. In this work, we model the distribution of water vapor in protoplanetary disks with a thermo-chemical code. For a set of parameterized disk models, we calculate the distribution of dust temperature and radiation field of the disk with a Monte Carlo method, and then solve the gas temperature distribution and chemical composition. The radiative transfer includes detailed treatment of scattering by atomic hydrogen and absorption by water of Lyα photons, since the Lyα line dominates the UV spectrum of accreting young stars. In a fiducial model, we find that warm water vapormore » with temperature around 300 K is mainly distributed in a small and well-confined region in the inner disk. The inner boundary of the warm water region is where the shielding of UV field due to dust and water itself become significant. The outer boundary is where the dust temperature drops below the water condensation temperature. A more luminous central star leads to a more extended distribution of warm water vapor, while dust growth and settling tends to reduce the amount of warm water vapor. Based on typical assumptions regarding the elemental oxygen abundance and the water chemistry, the column density of warm water vapor can be as high as 10{sup 22} cm{sup –2}. A small amount of hot water vapor with temperature higher than ∼300 K exists in a more extended region in the upper atmosphere of the disk. Cold water vapor with temperature lower than 100 K is distributed over the entire disk, produced by photodesorption of the water ice.« less

Cooperation and Environment Characterize the Low-Lying Optical Spectrum of Liquid Water.

PubMed

P, Sudheer Kumar; Genova, Alessandro; Pavanello, Michele

2017-10-19

The optical spectrum of liquid water is analyzed by subsystem time-dependent density functional theory. We provide simple explanations for several important (and so far elusive) features. Due to the disordered environment surrounding each water molecule, the joint density of states of the liquid is much broader than that of the vapor, thus explaining the red-shifted Urbach tail of the liquid compared to the gas phase. Confinement effects provided by the first solvation shell are responsible for the blue shift of the first absorption peak compared to the vapor. In addition, we also characterize many-body excitonic effects. These dramatically affect the spectral weights at low frequencies, contributing to the refractive index by a small but significant amount.

Experimental evidence supporting the insensitivity of cloud droplet formation to the mass accommodation coefficient for condensation of water vapor to liquid water

NASA Astrophysics Data System (ADS)

Langridge, Justin M.; Richardson, Mathews S.; Lack, Daniel A.; Murphy, Daniel M.

2016-06-01

The mass accommodation coefficient for uptake of water vapor to liquid water, αM, has been constrained using photoacoustic measurements of aqueous absorbing aerosol. Measurements performed over a range of relative humidities and pressures were compared to detailed model calculations treating coupled heat and mass transfer occurring during photoacoustic laser heating cycles. The strengths and weaknesses of this technique are very different to those for droplet growth/evaporation experiments that have typically been applied to these measurements, making this a useful complement to existing studies. Our measurements provide robust evidence that αM is greater than 0.1 for all humidities tested and greater than 0.3 for data obtained at relative humidities greater than 88% where the aerosol surface was most like pure water. These values of αM are above the threshold at which kinetic limitations are expected to impact the activation and growth of aerosol particles in warm cloud formation.

Non-aqueous phase liquid spreading during soil vapor extraction

PubMed Central

Kneafsey, Timothy J.; Hunt, James R.

2010-01-01

Many non-aqueous phase liquids (NAPLs) are expected to spread at the air – water interface, particularly under non-equilibrium conditions. In the vadose zone, this spreading should increase the surface area for mass transfer and the efficiency of volatile NAPL recovery by soil vapor extraction (SVE). Observations of spreading on water wet surfaces led to a conceptual model of oil spreading vertically above a NAPL pool in the vadose zone. Analysis of this model predicts that spreading can enhance the SVE contaminant recovery compared to conditions where the liquid does not spread. Experiments were conducted with spreading volatile oils hexane and heptane in wet porous media and capillary tubes, where spreading was observed at the scale of centimeters. Within porous medium columns up to a meter in height containing stagnant gas, spreading was less than ten centimeters and did not contribute significantly to hexane volatilization. Water film thinning and oil film pinning may have prevented significant oil film spreading, and thus did not enhance SVE at the scale of a meter. The experiments performed indicate that volatile oil spreading at the field scale is unlikely to contribute significantly to the efficiency of SVE. PMID:14734243

Water Vapor Effects on Silica-Forming Ceramics

NASA Technical Reports Server (NTRS)

Opila, E. J.; Greenbauer-Seng, L. (Technical Monitor)

2000-01-01

Silica-forming ceramics such as SiC and Si3N4 are proposed for applications in combustion environments. These environments contain water vapor as a product of combustion. Oxidation of silica-formers is more rapid in water vapor than in oxygen. Parabolic oxidation rates increase with the water vapor partial pressure with a power law exponent value close to one. Molecular water vapor is therefore the mobile species in silica. Rapid oxidation rates and large amounts of gases generated during the oxidation reaction in high water vapor pressures may result in bubble formation in the silica and nonprotective scale formation. It is also shown that silica reacts with water vapor to form Si(OH)4(g). Silica volatility has been modeled using a laminar flow boundary layer controlled reaction equation. Silica volatility depends on the partial pressure of water vapor, the total pressure, and the gas velocity. Simultaneous oxidation and volatilization reactions have been modeled with paralinear kinetics.

Study of the liquid vapor equilibrium in the bromine-hydrobromic acid-water system

NASA Technical Reports Server (NTRS)

Benizri, R.; Lessart, P.; Courvoisier, P.

1984-01-01

A glass ebullioscope was built and at atmospheric pressure, liquid-vapor equilibria relative to the Br2-HBr-H2O system, in the concentration range of interest for evaluation of the Mark 13 cycle was studied. Measurements were performed for the brome-azeotrope (HBr-H2O) pseudo-binary system and for the ternary system at temperatures lower than 125 C and in the bromine concentration range up to 13% wt.

Revisiting a many-body model for water based on a single polarizable site: from gas phase clusters to liquid and air/liquid water systems.

PubMed

Réal, Florent; Vallet, Valérie; Flament, Jean-Pierre; Masella, Michel

2013-09-21

We present a revised version of the water many-body model TCPE [M. Masella and J.-P. Flament, J. Chem. Phys. 107, 9105 (1997)], which is based on a static three charge sites and a single polarizable site to model the molecular electrostatic properties of water, and on an anisotropic short range many-body energy term specially designed to accurately model hydrogen bonding in water. The parameters of the revised model, denoted TCPE/2013, are here developed to reproduce the ab initio energetic and geometrical properties of small water clusters (up to hexamers) and the repulsive water interactions occurring in cation first hydration shells. The model parameters have also been refined to reproduce two liquid water properties at ambient conditions, the density and the vaporization enthalpy. Thanks to its computational efficiency, the new model range of applicability was validated by performing simulations of liquid water over a wide range of temperatures and pressures, as well as by investigating water liquid/vapor interfaces over a large range of temperatures. It is shown to reproduce several important water properties at an accurate enough level of precision, such as the existence liquid water density maxima up to a pressure of 1000 atm, the water boiling temperature, the properties of the water critical point (temperature, pressure, and density), and the existence of a "singularity" temperature at about 225 K in the supercooled regime. This model appears thus to be particularly well-suited for characterizing ion hydration properties under different temperature and pressure conditions, as well as in different phases and interfaces.

The application of the high-speed photography in the experiments of boiling liquid expanding vapor explosions

NASA Astrophysics Data System (ADS)

Chen, Sining; Sun, Jinhua; Chen, Dongliang

2007-01-01

The liquefied-petroleum gas tank in some failure situations may release its contents, and then a series of hazards with different degrees of severity may occur. The most dangerous accident is the boiling liquid expanding vapor explosion (BLEVE). In this paper, a small-scale experiment was established to experimentally investigate the possible processes that could lead to a BLEVE. As there is some danger in using LPG in the experiments, water was used as the test fluid. The change of pressure and temperature was measured during the experiment. The ejection of the vapor and the sequent two-phase flow were recorded by a high-speed video camera. It was observed that two pressure peaks result after the pressure is released. The vapor was first ejected at a high speed; there was a sudden pressure drop which made the liquid superheated. The superheated liquid then boiled violently causing the liquid contents to swell, and also, the vapor pressure in the tank increased rapidly. The second pressure peak was possibly due to the swell of this two-phase flow which was likely to violently impact the wall of the tank with high speed. The whole evolution of the two-phase flow was recorded through photos captured by the high-speed video camera, and the "two step" BLEVE process was confirmed.

Paradoxes of thermodynamics of swelling equilibria of polymers in liquids and vapors.

PubMed

Davankov, Vadim A; Pastukhov, Alexander V

2011-12-29

An automatic registration of the changing size of a single spherical microbead of a cross-linked polymer was applied for studying the swelling process of the bead by the sorption of vapors and/or liquids. Many representatives of all three basic types of polymeric networks, gel-type, hypercrosslinked, and macroporous, were examined. Only the first two display large volume changes and prove suitable for following the kinetics and extent of swelling by the above dilatometric technique. The results unambiguously prove that swelling of all polymeric networks in liquids is always higher than in corresponding saturated vapors (Schroeder's paradox). The general nature of this phenomenon implies that the absolute activity of any sorbate in its liquid form is always larger than in the form of its saturated vapor. Surprisingly, gels with any solvent contents, which fall into the broad range between the vapor-equilibrated and liquid-equilibrated extreme contents, retain their volumes constant in the saturated vapor atmosphere. This paradox of a wide range of gels swollen to a different extent and, nevertheless, standing in equilibrium with saturated vapor is explained by the specificity of the network polymers, namely, that the energy of the solvent-polymer interactions is easily compensated by the energy of remaining between-chain interactions at any solvent content in the above range. Therefore, the strain-free swollen gels do not generate enhanced vapor pressure, but neither display the ability to take up more sorbate from its vapor. © 2011 American Chemical Society

Electro-Osmosis and Water Uptake in Polymer Electrolytes in Equilibrium with Water Vapor at Low Temperatures

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

Gallagher, K. G.; Pivovar, B. S.; Fuller, T. F.

2009-01-01

Water uptake and electro-osmosis are investigated to improve the understanding and aid the modeling of water transport in proton-exchange membrane fuel cells (PEMFCs) below 0 C. Measurements of water sorption isotherms show a significant reduction in the water capacity of polymer electrolytes below 0 C. This reduced water content is attributed to the lower vapor pressure of ice compared to supercooled liquid water. At -25 C, 1100 equivalent weight Nafion in equilibrium with vapor over ice has 8 moles of water per sulfonic acid group. Measurements of the electro-osmotic drag coefficient for Nafion and both random and multiblock copolymer sulfonatedmore » poly(arylene ether sulfone) (BPSH) chemistries are reported for vapor equilibrated samples below 0 C. The electro-osmotic drag coefficient of BPSH chemistries is found to be {approx}0.4, and that of Nafion is {approx}1. No significant temperature effect on the drag coefficient is found. The implication of an electro-osmotic drag coefficient less than unity is discussed in terms of proton conduction mechanisms. Simulations of the ohmically limited current below 0 C show that a reduced water uptake below 0 C results in a significant decrease in PEMFC performance.« less

Extracting the pair distribution function of liquids and liquid-vapor surfaces by grazing incidence x-ray diffraction mode.

PubMed

Vaknin, David; Bu, Wei; Travesset, Alex

2008-07-28

We show that the structure factor S(q) of water can be obtained from x-ray synchrotron experiments at grazing angle of incidence (in reflection mode) by using a liquid surface diffractometer. The corrections used to obtain S(q) self-consistently are described. Applying these corrections to scans at different incident beam angles (above the critical angle) collapses the measured intensities into a single master curve, without fitting parameters, which within a scale factor yields S(q). Performing the measurements below the critical angle for total reflectivity yields the structure factor of the top most layers of the water/vapor interface. Our results indicate water restructuring at the vapor/water interface. We also introduce a new approach to extract g(r), the pair distribution function (PDF), by expressing the PDF as a linear sum of error functions whose parameters are refined by applying a nonlinear least square fit method. This approach enables a straightforward determination of the inherent uncertainties in the PDF. Implications of our results to previously measured and theoretical predictions of the PDF are also discussed.

Global analyses of water vapor, cloud and precipitation derived from a diagnostic assimilation of SSM/I geophysical retrievals

NASA Technical Reports Server (NTRS)

Robertson, Franklin R.; Cohen, Charles

1990-01-01

An analytical approach is described for diagnostically assimilating moisture data from Special Sensor Microwave Imager (SSM/I) into a global analysis of water vapor, cloud content, and precipitation. In this method, 3D fields of wind and temperature values taken from ECMWF gridded analysis are used to drive moisture conservation equations with parameterized microphysical treatment of vapor, liquid, and ice; the evolving field of water vapor is periodically updated or constrained by SSM/I retrievals of precipitable water. Initial results indicate that this diagnostic model can produce realistic large-scale fields of cloud and precipitation. The resulting water vapor analyses agree well with SSM/I and have an additional advantage of being synoptic.

Vapor-Deposited Glasses with Long-Range Columnar Liquid Crystalline Order

DOE PAGES

Gujral, Ankit; Gomez, Jaritza; Ruan, Shigang; ...

2017-10-04

Anisotropic molecular packing, particularly in highly ordered liquid crystalline arrangements, has the potential for optimizing performance in organic electronic and optoelectronic applications. Here we show that physical vapor deposition can be used to prepare highly organized glassy solids of discotic liquid crystalline systems. Using grazing incidence X-ray scattering, atomic force microscopy, and UV–vis spectroscopy, we compare three systems: a rectangular columnar liquid crystal, a hexagonal columnar liquid crystal, and a nonmesogen. The packing motifs accessible by vapor deposition are highly organized for the liquid crystalline systems with columns propagating either in-plane or out-of-plane depending upon the substrate temperature during deposition.more » As a result, the structures formed at a given substrate temperature can be understood as resulting from partial equilibration toward the structure of the equilibrium liquid crystal surface during the deposition process.« less

Vapor-Deposited Glasses with Long-Range Columnar Liquid Crystalline Order

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

Gujral, Ankit; Gomez, Jaritza; Ruan, Shigang

Anisotropic molecular packing, particularly in highly ordered liquid crystalline arrangements, has the potential for optimizing performance in organic electronic and optoelectronic applications. Here we show that physical vapor deposition can be used to prepare highly organized glassy solids of discotic liquid crystalline systems. Using grazing incidence X-ray scattering, atomic force microscopy, and UV–vis spectroscopy, we compare three systems: a rectangular columnar liquid crystal, a hexagonal columnar liquid crystal, and a nonmesogen. The packing motifs accessible by vapor deposition are highly organized for the liquid crystalline systems with columns propagating either in-plane or out-of-plane depending upon the substrate temperature during deposition.more » As a result, the structures formed at a given substrate temperature can be understood as resulting from partial equilibration toward the structure of the equilibrium liquid crystal surface during the deposition process.« less

Effects of thermal vapor diffusion on seasonal dynamics of water in the unsaturated zone

USGS Publications Warehouse

Milly, Paul C.D.

1996-01-01

The response of water in the unsaturated zone to seasonal changes of temperature (T) is determined analytically using the theory of nonisothermal water transport in porous media, and the solutions are tested against field observations of moisture potential and bomb fallout isotopic (36Cl and 3H) concentrations. Seasonally varying land surface temperatures and the resulting subsurface temperature gradients induce thermal vapor diffusion. The annual mean vertical temperature gradient is close to zero; however, the annual mean thermal vapor flux is downward, because the temperature‐dependent vapor diffusion coefficient is larger, on average, during downward diffusion (occurring at high T) than during upward diffusion (low T). The annual mean thermal vapor flux is shown to decay exponentially with depth; the depth (about 1 m) at which it decays to e−1of its surface value is one half of the corresponding decay depth for the amplitude of seasonal temperature changes. This depth‐dependent annual mean flux is effectively a source of water, which must be balanced by a flux divergence associated with other transport processes. In a relatively humid environment the liquid fluxes greatly exceed the thermal vapor fluxes, so such a balance is readily achieved without measurable effect on the dynamics of water in the unsaturated zone. However, if the mean vertical water flux through the unsaturated zone is very small (<1 mm y−1), as it may be at many locations in a desert landscape, the thermal vapor flux must be balanced mostly by a matric‐potential‐induced upward flux of water. This return flux may include both vapor and liquid components. Below any near‐surface zone of weather‐related fluctuations of matric potential, maintenance of this upward flux requires an increase with depth in the annual mean matric potential; this theoretical prediction is supported by long‐term field measurements in the Chihuahuan Desert. The analysis also makes predictions

What Good is Raman Water Vapor Lidar?

NASA Technical Reports Server (NTRS)

Whitman, David

2011-01-01

Raman lidar has been used to quantify water vapor in the atmosphere for various scientific studies including mesoscale meteorology and satellite validation. Now the international networks of NDACC and GRUAN have interest in using Raman water vapor lidar for detecting trends in atmospheric water vapor concentrations. What are the data needs for addressing these very different measurement challenges. We will review briefly the scientific needs for water vapor accuracy for each of these three applications and attempt to translate that into performance specifications for Raman lidar in an effort to address the question in the title of "What good is Raman water vapor Iidar."

40 CFR 264.1057 - Standards: Valves in gas/vapor service or in light liquid -service.

Code of Federal Regulations, 2014 CFR

2014-07-01

...: Valves in gas/vapor service or in light liquid -service. (a) Each valve in gas/vapor or light liquid... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Standards: Valves in gas/vapor service or in light liquid -service. 264.1057 Section 264.1057 Protection of Environment ENVIRONMENTAL...

40 CFR 264.1057 - Standards: Valves in gas/vapor service or in light liquid -service.

Code of Federal Regulations, 2011 CFR

2011-07-01

...: Valves in gas/vapor service or in light liquid -service. (a) Each valve in gas/vapor or light liquid... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Standards: Valves in gas/vapor service or in light liquid -service. 264.1057 Section 264.1057 Protection of Environment ENVIRONMENTAL...

40 CFR 264.1057 - Standards: Valves in gas/vapor service or in light liquid -service.

Code of Federal Regulations, 2010 CFR

2010-07-01

...: Valves in gas/vapor service or in light liquid -service. (a) Each valve in gas/vapor or light liquid... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service or in light liquid -service. 264.1057 Section 264.1057 Protection of Environment ENVIRONMENTAL...

40 CFR 264.1057 - Standards: Valves in gas/vapor service or in light liquid -service.

Code of Federal Regulations, 2012 CFR

2012-07-01

...: Valves in gas/vapor service or in light liquid -service. (a) Each valve in gas/vapor or light liquid... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Standards: Valves in gas/vapor service or in light liquid -service. 264.1057 Section 264.1057 Protection of Environment ENVIRONMENTAL...

40 CFR 264.1057 - Standards: Valves in gas/vapor service or in light liquid -service.

Code of Federal Regulations, 2013 CFR

2013-07-01

...: Valves in gas/vapor service or in light liquid -service. (a) Each valve in gas/vapor or light liquid... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Standards: Valves in gas/vapor service or in light liquid -service. 264.1057 Section 264.1057 Protection of Environment ENVIRONMENTAL...

Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor-Liquid Equilibrium

NASA Astrophysics Data System (ADS)

Yamamoto, Hideki; Sumoge, Iwao

2011-03-01

This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 mass%). An acid mixture of nitric acid (5.0 mol · dm-3) and hydrofluoric acid (5.0 mol · dm-3) was prepared as a sample solution for distillation tests. The concentration of nitric acid in the first distillate decreased from 5.0 mol · dm-3 to 1.13 mol · dm-3, and the concentration of hydrofluoric acid increased to 5.41 mol · dm-3. This first distillate was further distilled without the addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol · dm-3 and 0.46 mol · dm-3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.

Vapor and liquid optical monitoring with sculptured Bragg microcavities

NASA Astrophysics Data System (ADS)

Oliva-Ramirez, Manuel; Gil-Rostra, Jorge; López-Santos, Maria C.; González-Elipe, Agustín. R.; Yubero, Francisco

2017-08-01

Sculptured porous Bragg Microcavities (BMs) formed by the successive stacking of columnar SiO2 and TiO2 thin films with zig-zag columnar microstructure are prepared by glancing angle deposition. These BMs act as wavelength dependent optical retarders. This optical behavior is attributed to a self-structuration mechanism involving a fence-bundling association of nanocolumns as observed by Focused Ion Beam Scanning Electron Microscopy. The retardance of these optically active BMs can be modulated by dynamic infiltration of their open porosity with vapors, liquids or solutions with different refractive indices. The tunable birefringence of these nanostructured photonic systems have been successfully simulated with a simple model that assumes that each layer within the BMs stack has uniaxial birefringence. This type of self-associated nanostructures has been incorporated to microfluidic chips for free label vapor and liquid sensing. Several examples of the detection performance of these chips, working either in reflection or transmission configuration, for the optical characterization of vapor and liquids of different refractive index and aqueous solutions of glucose flowing through the microfluidic chips are described.

Calculating the enthalpy of vaporization for ionic liquid clusters.

PubMed

Kelkar, Manish S; Maginn, Edward J

2007-08-16

Classical atomistic simulations are used to compute the enthalpy of vaporization of a series of ionic liquids composed of 1-alkyl-3-methylimidazolium cations paired with the bis(trifluoromethylsulfonyl)imide anion. The calculations show that the enthalpy of vaporization is lowest for neutral ion pairs. The enthalpy of vaporization increases by about 40 kJ/mol with the addition of each ion pair to the vaporizing cluster. Non-neutral clusters have much higher vaporization enthalpies than their neutral counterparts and thus are not expected to make up a significant fraction of volatile species. The enthalpy of vaporization increases slightly as the cation alkyl chain length increases and as temperature decreases. The calculated vaporization enthalpies are consistent with two sets of recent experimental measurements as well as with previous atomistic simulations.

Water vapor profiling using microwave radiometry

NASA Technical Reports Server (NTRS)

Wang, J. R.; Wilheit, T. T.

1988-01-01

Water vapor is one of the most important constituents in the Earth's atmosphere. Its spatial and temporal variations affect a wide spectrum of meteorological phenomena ranging from the formation of clouds to the development of severe storms. The passive microwave technique offers an excellent means for water vapor measurements. It can provide both day and night coverage under most cloud conditions. Two water vapor absorption features, at 22 and 183 GHz, were explored in the past years. The line strengths of these features differ by nearly two orders of magnitude. As a consequence, the techniques and the final products of water vapor measurements are also quite different. The research effort in the past few years was to improve and extend the retrieval algorithm to the measurements of water vapor profiles under cloudy conditions. In addition, the retrieval of total precipitable water using 183 GHz measurements, but in a manner analogous to the use of 22 GHz measurements, to increase measurement sensitivity for atmospheres of very low moisture content was also explored.

Optical monitor for water vapor concentration

DOEpatents

Kebabian, Paul

1998-01-01

A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma.

Optical monitor for water vapor concentration

DOEpatents

Kebabian, P.

1998-06-02

A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma. 5 figs.

Combination downflow-upflow vapor-liquid separator

DOEpatents

Kidwell, John H.; Prueter, William P.; Eaton, Andrew M.

1987-03-10

An improved vapor-liquid separator having a vertically disposed conduit for flow of a mixture. A first, second and third plurality of curved arms penetrate and extend within the conduit. A cylindrical member is radially spaced from the conduit forming an annulus therewith and having perforations and a retaining lip at its upper end.

Analyses on Water Vapor Resource in Chengdu City

NASA Astrophysics Data System (ADS)

Liu, B.; Xiao, T.; Wang, C.; Chen, D.

2017-12-01

Chengdu is located in the Sichuan basin, and it is the most famous inland city in China. With suitable temperatures and rainfall, Chengdu is the most livable cities in China. With the development of urban economy and society, the population has now risen to 16 million, and it will up to 22 million in 2030. This will cause the city water resources demand, and the carrying capacity of water resources become more and more serious. In order to improve the contradiction between urban waterlogging and water shortage, sponge city planning was proposed by Chengdu government, and this is of great practical significance for promoting the healthy development of the city. Base on the reanalysis data from NCEP during 2007-2016, the characters of Water Vapor Resources was analyzed, and the main contents of this research are summarized as follows: The water vapor resource in Chengdu plain is more than that in Southeast China and less in Northwest China. The annual average water vapor resource is approximately 160 mm -320 mm, and the water vapor resource in summer can reach 3 times in winter. But the annual average precipitation in Chengdu is about 800 mm -1200 mm and it is far greater than the water vapor resource, this is because of the transport of water vapor. Using the formula of water vapor flux, the water vapor in Chengdu is comes from the west and the south, and the value is around 50kg/(ms). Base on the calculation of boundary vapor budget, the water vapor transport under 500hPa accounted for 97% of the total. Consider the water vapor transport, transformation and urban humidification effect, the Water Vapor Resource in Chengdu is 2500mm, and it can be used by artificial precipitation enhancement. Therefore, coordinated development of weather modification and sponge city construction, the shortage of water resources in Chengdu plain can be solved. Key words: Chengdu; Sponge city; Water vapor resource; Precipitation; Artificial precipitation enhancement Acknowledgements

A novel membrane device for the removal of water vapor and water droplets from air

NASA Technical Reports Server (NTRS)

Ray, Rod; Newbold, David D.; Mccray, Scott B.; Friesen, Dwayne T.; Kliss, Mark

1992-01-01

One of the key challenges facing NASA engineers is the development of systems for separating liquids and gases in microgravity environments. In this paper, a novel membrane-based phase separator is described. This device, known as a water recovery heat exchanger (WRHEX), overcomes the inherent deficiencies of current phase-separation technology. Specifically, the WRHEX cools and removes water vapor or water droplets from feed-air streams without the use of a vacuum or centrifugal force. As is shown in this paper, only a low-power air blower and a small stream of recirculated cool water is required for WRHEX operation. This paper presents the results of tests using this novel membrane device over a wide range of operating conditions. The data show that the WRHEX produces a dry air stream containing no entrained or liquid water - even when the feed air contains water droplets or mist. An analysis of the operation of the WRHEX is presented.

Profiling atmospheric water vapor by microwave radiometry

NASA Technical Reports Server (NTRS)

Wang, J. R.; Wilheit, T. T.; Szejwach, G.; Gesell, L. H.; Nieman, R. A.; Niver, D. S.; Krupp, B. M.; Gagliano, J. A.; King, J. L.

1983-01-01

High-altitude microwave radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric water vapor profiles over both land and water. An algorithm based on an extended kalman-Bucy filter was implemented and applied for the water vapor retrieval. The results show great promise in atmospheric water vapor profiling by microwave radiometry heretofore not attainable at lower frequencies.

Ultra-trace determination of gold nanoparticles in environmental water by surfactant assisted dispersive liquid liquid microextraction coupled with electrothermal vaporization-inductively coupled plasma-mass spectrometry

NASA Astrophysics Data System (ADS)

Liu, Ying; He, Man; Chen, Beibei; Hu, Bin

2016-08-01

A new method by coupling surfactant assisted dispersive liquid liquid microextraction (SA-DLLME) with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) was proposed for the analysis of gold nanoparticles (AuNPs) in environmental water samples. Effective separation of AuNPs from ionic gold species was achieved by using sodium thiosulphate as a complexing agent. Various experimental parameters affecting SA-DLLME of AuNPs, such as the organic solvent, organic solvent volume, pH of the sample, the kind of surfactant, surfactant concentration, vortex time, speed of centrifugation, centrifugation time, and different coating as well as sizes of AuNPs were investigated carefully. Furthermore, the interference of coexisting ions, dissolved organic matter (DOM) and other metal nanoparticles (NPs) were studied. Under the optimal conditions, a detection limit of 2.2 ng L- 1 and an enrichment factor of 152-fold was achieved for AuNPs, and the original morphology of the AuNPs could be maintained during the extraction process. The developed method was successfully applied for the analysis of AuNPs in environmental water samples, including tap water, the East Lake water, and the Yangtze River water, with recoveries in the range of 89.6-102%. Compared with the established methods for metal NPs analysis, the proposed method has the merits of simple and fast operation, low detection limit, high selectivity, good tolerance to the sample matrix and no digestion or dilution required. It provides an efficient quantification methodology for monitoring AuNPs' pollution in the environmental water and evaluating its toxicity.

Phase-field model of vapor-liquid-solid nanowire growth

NASA Astrophysics Data System (ADS)

Wang, Nan; Upmanyu, Moneesh; Karma, Alain

2018-03-01

We present a multiphase-field model to describe quantitatively nanowire growth by the vapor-liquid-solid (VLS) process. The free-energy functional of this model depends on three nonconserved order parameters that distinguish the vapor, liquid, and solid phases and describe the energetic properties of various interfaces, including arbitrary forms of anisotropic γ plots for the solid-vapor and solid-liquid interfaces. The evolution equations for those order parameters describe basic kinetic processes including the rapid (quasi-instantaneous) equilibration of the liquid catalyst to a droplet shape with constant mean curvature, the slow incorporation of growth atoms at the droplet surface, and crystallization within the droplet. The standard constraint that the sum of the phase fields equals unity and the conservation of the number of catalyst atoms, which relates the catalyst volume to the concentration of growth atoms inside the droplet, are handled via separate Lagrange multipliers. An analysis of the model is presented that rigorously maps the phase-field equations to a desired set of sharp-interface equations for the evolution of the phase boundaries under the constraint of force balance at three-phase junctions (triple points) given by the Young-Herring relation that includes torque term related to the anisotropy of the solid-liquid and solid-vapor interface excess free energies. Numerical examples of growth in two dimensions are presented for the simplest case of vanishing crystalline anisotropy and the more realistic case of a solid-liquid γ plot with cusped minima corresponding to two sets of (10 ) and (11 ) facets. The simulations reproduce many of the salient features of nanowire growth observed experimentally, including growth normal to the substrate with tapering of the side walls, transitions between different growth orientations, and crawling growth along the substrate. They also reproduce different observed relationships between the nanowire growth

Vapor and liquid optical monitoring with sculptured Bragg microcavities

NASA Astrophysics Data System (ADS)

Oliva-Ramirez, Manuel; Gil-Rostra, Jorge; López-Santos, Maria Carmen; González-Elipe, Agustín R.; Yubero, Francisco

2017-10-01

Sculptured porous Bragg microcavities (BMs) formed by the successive stacking of columnar SiO2 and TiO2 thin films with a zig-zag columnar microstructure are prepared by glancing angle deposition. These BMs act as wavelength-dependent optical retarders. This optical behavior is attributed to a self-structuration of the stacked layers involving the lateral association of nanocolumns in the direction perpendicular to the main flux of particles during the multilayer film growth, as observed by focused ion beam scanning electron microscopy. The retardance of these optically active BMs can be modulated by dynamic infiltration of their open porosity with vapors, liquids, or solutions with different refractive indices. The tunable birefringence of these nanostructured photonic systems has been successfully simulated with a simple model that assumes that each layer within the BMs stack has uniaxial birefringence. The sculptured BMs have been incorporated as microfluidic chips for optical transduction for label-free vapor and liquid sensing. Several examples of the detection performance of these chips, working either in reflection or transmission configuration, for the optical monitoring of vapor and liquids of different refractive indices and aqueous solutions of glucose flowing through the microfluidic chips are described.

Condensation on a noncollapsing vapor bubble in a subcooled liquid

NASA Technical Reports Server (NTRS)

Baumeister, K. J.; Simoneau, R. J.

1979-01-01

An experimental procedure is presented by which an estimate can be made of the condensation coefficient on a noncollapsing stationary vapor bubble in subcooled liquid nitrogen. Film boiling from a thin wire was used to generate vapor bubbles which remain fixed to the wire at their base. A balance was established between the evaporation in the thin annular region along the wire and the condensation in the vapor bubbles.

The impact of water vapor diodes on soil water redistribution

NASA Astrophysics Data System (ADS)

Wang, Zhuangji; Ankeny, Mark; Horton, Robert

2017-09-01

Diurnal soil temperature fluctuations are the prime cause for subsurface water vapor fluxes. In arid and semi-arid areas, water vapor flux is the dominant means of soil water redistribution. The directions of water vapor flux shift from upward to downward diurnally following the variations of the soil thermal gradient. A water vapor diode (WVD), acting as a check valve, allows water vapor flux in one direction but heat flux in both directions. By installing a subsurface WVD, it is possible to impose direction-controlled vapor fluxes, and WVDs can be used to accumulate or remove water in particular soil layers. The egg carton shape, with pores situated at selected peaks and valleys, is a possible design for WVDs. In this study, we provide the concept and the properties of the ideal WVDs, and we discuss four WVD configurations to control soil water redistribution. Numerical simulation is used to evaluate the impacts of the ideal WVDs. The results indicate that WVDs can increase local water contents by at least 0.1 m3m-3 in a silt loam. For a fixed initial water and thermal condition, the effect of WVDs is related to the deployment depth and distance between two consecutive WVDs. WVDs can be used to manipulate soil water redistribution and accumulate water at specific depths to support plant growth. The numerical simulation results indicate the potential effectiveness of the ideal WVDs, and field tests should be performed to determine their function under specific soil conditions.

Student Understanding of Liquid-Vapor Phase Equilibrium

ERIC Educational Resources Information Center

Boudreaux, Andrew; Campbell, Craig

2012-01-01

Student understanding of the equilibrium coexistence of a liquid and its vapor was the subject of an extended investigation. Written assessment questions were administered to undergraduates enrolled in introductory physics and chemistry courses. Responses have been analyzed to document conceptual and reasoning difficulties in sufficient detail to…

Vapor-liquid phase separator permeability results

NASA Technical Reports Server (NTRS)

Yuan, S. W. K.; Frederking, T. H. K.

1981-01-01

Continued studies are described in the area of vapor-liquid phase separator work with emphasis on permeabilities of porous sintered plugs (stainless steel, nominal pore size 2 micrometer). The temperature dependence of the permeability has been evaluated in classical fluid using He-4 gas at atmospheric pressure and in He-2 on the basis of a modified, thermosmotic permeability of the normal fluid.

The role of water vapor in climate. A strategic research plan for the proposed GEWEX water vapor project (GVaP)

NASA Technical Reports Server (NTRS)

Starr, D. OC. (Editor); Melfi, S. Harvey (Editor)

1991-01-01

The proposed GEWEX Water Vapor Project (GVaP) addresses fundamental deficiencies in the present understanding of moist atmospheric processes and the role of water vapor in the global hydrologic cycle and climate. Inadequate knowledge of the distribution of atmospheric water vapor and its transport is a major impediment to progress in achieving a fuller understanding of various hydrologic processes and a capability for reliable assessment of potential climatic change on global and regional scales. GVap will promote significant improvements in knowledge of atmospheric water vapor and moist processes as well as in present capabilities to model these processes on global and regional scales. GVaP complements a number of ongoing and planned programs focused on various aspects of the hydrologic cycle. The goal of GVaP is to improve understanding of the role of water vapor in meteorological, hydrological, and climatological processes through improved knowledge of water vapor and its variability on all scales. A detailed description of the GVaP is presented.

Heating-induced glass-glass and glass-liquid transformations in computer simulations of water.

PubMed

Chiu, Janet; Starr, Francis W; Giovambattista, Nicolas

2014-03-21

Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T "phase diagram" for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related

Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

NASA Astrophysics Data System (ADS)

Chiu, Janet; Starr, Francis W.; Giovambattista, Nicolas

2014-03-01

Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T "phase diagram" for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related

Remote sensing of water vapor features

NASA Technical Reports Server (NTRS)

Fuelberg, Henry E.

1993-01-01

Water vapor plays a critical role in the atmosphere. It is an important medium of energy exchange between air, land, and water; it is a major greenhouse gas, providing a crucial radiative role in the global climate system; and it is intimately involved in many regional scale atmospheric processes. Our research has been aimed at improving satellite remote sensing of water vapor and better understanding its role in meteorological processes. Our early studies evaluated the current GOES VAS system for measuring water vapor and have used VAS-derived water vapor data to examine pre-thunderstorm environments. Much of that research was described at the 1991 Research Review. A second research component has considered three proposed sensors--the High resolution Interferometer Sounder (HIS), the Multispectral Atmospheric Mapping Sensor (MAMS), and the Advanced Microwave Sounding Unit (AMSU). We have focused on MAMS and AMSU research during the past year and the accomplishments made in this effort are presented.

Effect of perfluorocarbon (perfluorooctyl bromide) vapor on tidal volume measurement during partial liquid ventilation.

PubMed

Davies, Mark W; Dunster, Kimble R

2002-05-01

To compare measured tidal volumes with and without perfluorocarbon (perfluorooctyl bromide) vapor, by using tidal volumes in the range suitable for neonates ventilated with partial liquid ventilation. We also aimed to determine the correction factor needed to calculate tidal volumes measured in the presence of perfluorooctyl bromide vapor. Prospective, experimental study. Neonatal research laboratory. Reproducible tidal volumes from 5 to 30 mL were produced with a rodent ventilator and drawn from humidifier chambers immersed in a water bath at 37 degrees C. Control tidal volumes were drawn from a chamber containing oxygen and water vapor, and the perfluorocarbon tidal volumes were drawn from a chamber containing oxygen, water vapor, and perfluorooctyl bromide vapor. Tidal volumes were measured by a VenTrak respiratory mechanics monitor with a neonatal flow sensor and a Dräger pneumotachometer attached to a Dräger neonatal ventilator. All tidal volumes measured with perfluorooctyl bromide vapor were increased compared with control. The VenTrak-measured tidal volumes increased by 1.8% to 3.5% (an overall increase of 2.2%). The increase was greater with the Dräger hot-wire anemometer: from 2.4% to 6.1% (an overall increase of 5.9%). Regression equations for mean control tidal volumes (response, Y) vs. mean perfluorooctyl bromide tidal volumes (predictor, X) are as follows: for the VenTrak, Y = -0.026 + (0.978 x X), r =.9999, p <.0001; and for the Dräger, Y = 0.251 + (0.944 x X), r =.9996, p <.0001. The presence of perfluorooctyl bromide vapor in the gas flowing through pneumotachometers gives falsely high tidal volume measurements. An estimate of the true tidal volume allowing for the presence of perfluorooctyl bromide vapor can be made from regression equations. Any calculation of lung mechanics must take into account the effect of perfluorooctyl bromide vapor on the measurement of tidal volume.

Mid-infrared laser-absorption diagnostic for vapor-phase fuel mole fraction and liquid fuel film thickness

NASA Astrophysics Data System (ADS)

Porter, J. M.; Jeffries, J. B.; Hanson, R. K.

2011-02-01

A novel two-wavelength mid-infrared laser-absorption diagnostic has been developed for simultaneous measurements of vapor-phase fuel mole fraction and liquid fuel film thickness. The diagnostic was demonstrated for time-resolved measurements of n-dodecane liquid films in the absence and presence of n-decane vapor at 25°C and 1 atm. Laser wavelengths were selected from FTIR measurements of the C-H stretching band of vapor n-decane and liquid n-dodecane near 3.4 μm (3000 cm-1). n-Dodecane film thicknesses <20 μm were accurately measured in the absence of vapor, and simultaneous measurements of n-dodecane liquid film thickness and n-decane vapor mole fraction (300 ppm) were measured with <10% uncertainty for film thicknesses <10 μm. A potential application of the measurement technique is to provide accurate values of vapor mole fraction in combustion environments where strong absorption by liquid fuel or oil films on windows make conventional direct absorption measurements of the gas problematic.

Condensation of acetol and acetic acid vapor with sprayed liquid

USDA-ARS?s Scientific Manuscript database

A cellulose-derived fraction of biomass pyrolysis vapor was simulated by evaporating acetol and acetic acid (AA) from flasks on a hot plate. The liquid in the flasks was infused with heated nitrogen. The vapor/nitrogen stream was superheated in a tube oven and condensed by contact with a cloud of ...

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.

40 CFR 265.1057 - Standards: Valves in gas/vapor service or in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

....1057 Standards: Valves in gas/vapor service or in light liquid service. (a) Each valve in gas/vapor or... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Standards: Valves in gas/vapor service or in light liquid service. 265.1057 Section 265.1057 Protection of Environment ENVIRONMENTAL...

40 CFR 265.1057 - Standards: Valves in gas/vapor service or in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

....1057 Standards: Valves in gas/vapor service or in light liquid service. (a) Each valve in gas/vapor or... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service or in light liquid service. 265.1057 Section 265.1057 Protection of Environment ENVIRONMENTAL...

40 CFR 265.1057 - Standards: Valves in gas/vapor service or in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

....1057 Standards: Valves in gas/vapor service or in light liquid service. (a) Each valve in gas/vapor or... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Standards: Valves in gas/vapor service or in light liquid service. 265.1057 Section 265.1057 Protection of Environment ENVIRONMENTAL...

40 CFR 265.1057 - Standards: Valves in gas/vapor service or in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

....1057 Standards: Valves in gas/vapor service or in light liquid service. (a) Each valve in gas/vapor or... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Standards: Valves in gas/vapor service or in light liquid service. 265.1057 Section 265.1057 Protection of Environment ENVIRONMENTAL...

40 CFR 265.1057 - Standards: Valves in gas/vapor service or in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

....1057 Standards: Valves in gas/vapor service or in light liquid service. (a) Each valve in gas/vapor or... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Standards: Valves in gas/vapor service or in light liquid service. 265.1057 Section 265.1057 Protection of Environment ENVIRONMENTAL...

Water vapor diffusion membranes, 2

NASA Technical Reports Server (NTRS)

Holland, F. F.; Klein, E.; Smith, J. K.; Eyer, C.

1976-01-01

Transport mechanisms were investigated for the three different types of water vapor diffusion membranes. Membranes representing porous wetting and porous nonwetting structures as well as dense diffusive membrane structures were investigated for water permeation rate as a function of: (1) temperature, (2) solids composition in solution, and (3) such hydrodynamic parameters as sweep gas flow rate, solution flow rate and cell geometry. These properties were measured using nitrogen sweep gas to collect the effluent. In addition, the chemical stability to chromic acid-stabilized urine was measured for several of each type of membrane. A technology based on the mechanism of vapor transport was developed, whereby the vapor diffusion rates and relative susceptibility of membranes to fouling and failure could be projected for long-term vapor recovery trials using natural chromic acid-stabilized urine.

The Relation between Vaporization Enthalpies and Viscosities: Eyring's Theory Applied to Selected Ionic Liquids.

PubMed

Bonsa, Anne-Marie; Paschek, Dietmar; Zaitsau, Dzmitry H; Emel'yanenko, Vladimir N; Verevkin, Sergey P; Ludwig, Ralf

2017-05-19

Key properties for the use of ionic liquids as electrolytes in batteries are low viscosities, low vapor pressure and high vaporization enthalpies. Whereas the measurement of transport properties is well established, the determination of vaporization enthalpies of these extremely low volatile compounds is still a challenge. At a first glance both properties seem to describe different thermophysical phenomena. However, eighty years ago Eyring suggested a theory which related viscosities and vaporization enthalpies to each other. The model is based on Eyring's theory of absolute reaction rates. Recent attempts to apply Eyring's theory to ionic liquids failed. The motivation of our study is to show that Eyring's theory works, if the assumptions specific for ionic liquids are fulfilled. For that purpose we measured the viscosities of three well selected protic ionic liquids (PILs) at different temperatures. The temperature dependences of viscosities were approximated by the Vogel-Fulcher-Tamann (VFT) relation and extrapolated to the high-temperature regime up to 600 K. Then the VFT-data could be fitted to the Eyring-model. The values of vaporization enthalpies for the three selected PILs predicted by the Eyring model have been very close to the experimental values measured by well-established techniques. We conclude that the Eyring theory can be successfully applied to the chosen set of PILs, if the assumption that ionic pairs of the viscous flow in the liquid and the ionic pairs in the gas phase are similar is fulfilled. It was also noticed that proper transfer of energies can be only derived if the viscosities and the vaporization energies are known for temperatures close to the liquid-gas transition temperature. The idea to correlate easy measurable viscosities of ionic liquids with their vaporization enthalpies opens a new way for a reliable assessment of these thermodynamic properties for a broad range of ionic liquids. © 2017 Wiley-VCH Verlag GmbH & Co. KGa

Advances in Raman Lidar Measurements of Water Vapor, Cirrus Clouds and Carbon Dioxide

NASA Technical Reports Server (NTRS)

Whiteman, David N.; Potter, John R.; Tola, Rebecca; Rush, Kurt; Veselovskii, Igor; Cadirola, Martin; Comer, Joseph

2006-01-01

Narrow-band interference filters with improved transmission in the ultraviolet have been developed under NASA-funded research and used in the Raman Airborne Spectroscopic Lidar (RASL) in ground- based, upward-looking tests. RASL is an airborne Raman Lidar system designed to measure water vapor mixing ratio, and aerosol backscatter/extinction/depolarization. It also possesses the capability to make experimental measurements of cloud liquid water and carbon dioxide. It is being prepared for first flight tests during the summer of 2006. With the newly developed filters installed in RASL, measurements were made of atmospheric water vapor, cirrus cloud optical properties and carbon dioxide that improve upon any previously demonstrated using Raman lidar. Daytime boundary layer profiling of water vapor mixing ratio is performed with less than 5% random error using temporal and spatial resolution of 2-minutes and 60 - 210, respectively. Daytime cirrus cloud optical depth and extinction- to-backscatter ratio measurements are made using 1-minute average. Sufficient signal strength is demonstrated to permit the simultaneous profiling of carbon dioxide and water vapor mixing ratio into the free troposphere during the nighttime. Downward-looking from an airborne RASL should possess the same measurement statistics with approximately a factor of 5 - 10 decrease in averaging time. A description of the technology improvements are provided followed by examples of the improved Raman lidar measurements.

Nonequilibrium kinetic boundary condition at the vapor-liquid interface of argon

NASA Astrophysics Data System (ADS)

Ishiyama, Tatsuya; Fujikawa, Shigeo; Kurz, Thomas; Lauterborn, Werner

2013-10-01

A boundary condition for the Boltzmann equation (kinetic boundary condition, KBC) at the vapor-liquid interface of argon is constructed with the help of molecular dynamics (MD) simulations. The KBC is examined at a constant liquid temperature of 85 K in a wide range of nonequilibrium states of vapor. The present investigation is an extension of a previous one by Ishiyama, Yano, and Fujikawa [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.95.084504 95, 084504 (2005)] and provides a more complete form of the KBC. The present KBC includes a thermal accommodation coefficient in addition to evaporation and condensation coefficients, and these coefficients are determined in MD simulations uniquely. The thermal accommodation coefficient shows an anisotropic behavior at the interface for molecular velocities normal versus tangential to the interface. It is also found that the evaporation and condensation coefficients are almost constant in a fairly wide range of nonequilibrium states. The thermal accommodation coefficient of the normal velocity component is almost unity, while that of the tangential component shows a decreasing function of the density of vapor incident on the interface, indicating that the tangential velocity distribution of molecules leaving the interface into the vapor phase may deviate from the tangential parts of the Maxwell velocity distribution at the liquid temperature. A mechanism for the deviation of the KBC from the isotropic Maxwell KBC at the liquid temperature is discussed in terms of anisotropic energy relaxation at the interface. The liquid-temperature dependence of the present KBC is also discussed.

A "User-Friendly" Program for Vapor-Liquid Equilibrium.

ERIC Educational Resources Information Center

Da Silva, Francisco A.; And Others

1991-01-01

Described is a computer software package suitable for teaching and research in the area of multicomponent vapor-liquid equilibrium. This program, which has a complete database, can accomplish phase-equilibrium calculations using various models and graph the results. (KR)

Clogging in staked-in needle pre-filled syringes (SIN-PFS): Influence of water vapor transmission through the needle shield.

PubMed

De Bardi, M; Müller, R; Grünzweig, C; Mannes, D; Rigollet, M; Bamberg, F; Jung, T A; Yang, K

2018-06-01

Staked-in needle pre-fillable syringes (SIN-PFS) are a convenient delivery system widely established in the growing pharmaceutical market. Under specific storage conditions, the needle of PFS containing high concentration drug product (DP) solution is prone to clogging, which prevents administration of the liquid. The purpose of this study is to clarify the clogging phenomenon of SIN-PFS and to elucidate the role of water vapor transmission via the needle shield. The presence of liquid within needles is a prerequisite condition for clogging and was investigated non-invasively by neutron imaging (NI) to confirm that liquid can migrate into the needle under certain processing conditions. The water vapor transmission rate (WVTR) of different needle shields was measured and the impact of temperature and relative humidity (rH) on the WVTR was investigated on sheets with the same composition as used in commercial needle shields. Our study clearly showed that the partial vapor pressure difference (ΔPP) across the needle shield is the dominant driving factor for water vapor transmission. A linear correlation between ΔPP and WVTR was found and a model to predict the water vapor transmission for PFS under specific storage conditions was developed. The impact of the WVTR on needle clogging was confirmed by clogging tests performed on SIN-PFS stored under different conditions. Thereby, we clearly show that high water loss induced by higher WVTR can be correlated to an increased occurrence of needle clogging. In conclusion, the WVTR of the needle shield plays a key role in needle clogging and the established WVTR model can be employed to assess the clogging risk for product development. Copyright © 2018 Elsevier B.V. All rights reserved.

QSPR analysis of the partitioning of vaporous chemicals in a water-gas phase system and the water solubility of liquid and solid chemicals on the basis of fragment and physicochemical similarity and hybot descriptors.

PubMed

Raevsky, O; Andreeva, E; Raevskaja, O; Skvortsov, V; Schaper, K

2005-01-01

QSPR analyses of the solubility in water of 558 vapors, 786 liquids and 2045 solid organic neutral chemicals and drugs are presented. Simultaneous consideration of H-bond acceptor and donor factors leads to a good description of the solubility of vapors and liquids. A volume-related term was found to have an essential negative contribution to the solubility of liquids. Consideration of polarizability, H-bond acceptor and donor factors and indicators for a few functional groups, as well as the experimental solubility values of structurally nearest neighbors yielded good correlations for liquids. The application of Yalkowsky's "General Solubility Equation" to 1063 solid chemicals and drugs resulted in a correlation of experimental vs calculated log S values with only modest statistical criteria. Two approaches to derive predictive models for solubility of solid chemicals and drugs were tested. The first approach was based on the QSPR for liquids together with indicator variables for different functional groups. Furthermore, a calculation of enthalpies for intermolecular complexes in crystal lattices, based on new H-bond potentials, was carried out for the better consideration of essential solubility- decreasing effects in the solid state, as compared with the liquid state. The second approach was based on a combination of similarity considerations and traditional QSPR. Both approaches lead to high quality predictions with average absolute errors on the level of experimental log S determination.

Effects of vertical distribution of water vapor and temperature on total column water vapor retrieval error

NASA Technical Reports Server (NTRS)

Sun, Jielun

1993-01-01

Results are presented of a test of the physically based total column water vapor retrieval algorithm of Wentz (1992) for sensitivity to realistic vertical distributions of temperature and water vapor. The ECMWF monthly averaged temperature and humidity fields are used to simulate the spatial pattern of systematic retrieval error of total column water vapor due to this sensitivity. The estimated systematic error is within 0.1 g/sq cm over about 70 percent of the global ocean area; systematic errors greater than 0.3 g/sq cm are expected to exist only over a few well-defined regions, about 3 percent of the global oceans, assuming that the global mean value is unbiased.

Interfacial nonequilibrium and Bénard-Marangoni instability of a liquid-vapor system

NASA Astrophysics Data System (ADS)

Margerit, J.; Colinet, P.; Lebon, G.; Iorio, C. S.; Legros, J. C.

2003-10-01

We study Bénard-Marangoni instability in a system formed by a horizontal liquid layer and its overlying vapor. The liquid is lying on a hot rigid plate and the vapor is bounded by a cold parallel plate. A pump maintains a reduced pressure in the vapor layer and evacuates the vapor. This investigation is undertaken within the classical quasisteady approximation for both the vapor and the liquid phases. The two layers are separated by a deformable interface. Temporarily frozen temperature and velocity distributions are employed at each instant for the stability analysis, limited to infinitesimal disturbances (linear regime). We use irreversible thermodynamics to model the phase change under interfacial nonequilibrium. Within this description, the interface appears as a barrier for transport of both heat and mass. Hence, in contrast with previous studies, we consider the possibility of a temperature jump across the interface, as recently measured experimentally. The stability analysis shows that the interfacial resistances to heat and mass transfer have a destabilizing influence compared to an interface that is in thermodynamic equilibrium. The role of the fluctuations in the vapor phase on the onset of instability is discussed. The conditions to reduce the system to a one phase model are also established. Finally, the influence of the evaporation parameters and of the presence of an inert gas on the marginal stability curves is discussed.

Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

PubMed

Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

2009-08-15

A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

Rate theory of ion pairing at the water liquid-vapor interface: A case of sodium iodide.

PubMed

Dang, Liem X; Schenter, Gregory K

2018-06-14

Studies on ion pairing at interfaces have been intensified recently because of their importance in many chemical reactive phenomena, such as ion-ion interactions that are affected by interfaces and their influence on kinetic processes. In this study, we performed simulations to examine the thermodynamics and kinetics of small polarizable sodium iodide ions in the bulk and near the water liquid-vapor interface. Using classical transition state theory, we calculated the dissociation rates and corrected them with transmission coefficients obtained from the reactive flux formalism and Grote-Hynes theory. Our results show that in addition to affecting the free energy of ions in solution, the interfacial environments significantly influence the kinetics of ion pairing. The results on the relaxation time obtained using the reactive flux formalism and Grote-Hynes theory present an unequivocal picture that the interface suppresses ion dissociation. The effects of the use of molecular models on the ion interactions as well as the ion-pair configurations at the interface are also quantified and discussed.

Rate theory of ion pairing at the water liquid-vapor interface: A case of sodium iodide

NASA Astrophysics Data System (ADS)

Dang, Liem X.; Schenter, Gregory K.

2018-06-01

Studies on ion pairing at interfaces have been intensified recently because of their importance in many chemical reactive phenomena, such as ion-ion interactions that are affected by interfaces and their influence on kinetic processes. In this study, we performed simulations to examine the thermodynamics and kinetics of small polarizable sodium iodide ions in the bulk and near the water liquid-vapor interface. Using classical transition state theory, we calculated the dissociation rates and corrected them with transmission coefficients obtained from the reactive flux formalism and Grote-Hynes theory. Our results show that in addition to affecting the free energy of ions in solution, the interfacial environments significantly influence the kinetics of ion pairing. The results on the relaxation time obtained using the reactive flux formalism and Grote-Hynes theory present an unequivocal picture that the interface suppresses ion dissociation. The effects of the use of molecular models on the ion interactions as well as the ion-pair configurations at the interface are also quantified and discussed.

Using Grand Canonical Monte Carlo Simulations to Understand the Role of Interfacial Fluctuations on Solvation at the Water-Vapor Interface.

PubMed

Rane, Kaustubh; van der Vegt, Nico F A

2016-09-15

The present work investigates the effect of interfacial fluctuations (predominantly capillary wave-like fluctuations) on the solvation free energy (Δμ) of a monatomic solute at the water-vapor interface. We introduce a grand-canonical-ensemble-based simulation approach that quantifies the contribution of interfacial fluctuations to Δμ. This approach is used to understand how the above contribution depends on the strength of dispersive and electrostatic solute-water interactions at the temperature of 400 K. At this temperature, we observe that interfacial fluctuations do play a role in the variation of Δμ with the strength of the electrostatic solute-water interaction. We also use grand canonical simulations to further investigate how interfacial fluctuations affect the propensity of the solute toward the water-vapor interface. To this end, we track a quantity called the interface potential (surface excess free energy) with the number of water molecules. With increasing number of water molecules, the liquid-vapor interface moves across a solute, which is kept at a fixed position in the simulation. Hence, the dependence of the interface potential on the number of waters models the process of moving the solute through the water-vapor interface. We analyze the change of the interface potential with the number of water molecules to explain that solute-induced changes in the interfacial fluctuations, like the pinning of capillary-wave-like undulations, do not play any role in the propensity of solutes toward water-vapor interfaces. The above analysis also shows that the dampening of interfacial fluctuations accompanies the adsorption of any solute at the liquid-vapor interface, irrespective of the chemical nature of the solute and solvent. However, such a correlation does not imply that dampening of fluctuations causes adsorption.

Effects of capillary heterogeneity on vapor-liquid counterflow in porous media

NASA Astrophysics Data System (ADS)

Stubos, A. K.; Satik, C.; Yortsos, Y. C.

1992-06-01

Based on a continuum description, the effect of capillary heterogeneity, induced by variation in permeability, on the steady state, countercurrent, vapor-liquid flow in porous media is analyzed. It is shown that the heterogeneity acts as a body force that may enhance or diminish gravity effects on heat pipes. Selection rules that determine the steady states reached in homogeneous, gravity-driven heat pipes are also formulated. It is shown that the 'infinite' two-phase zone may terminate by a substantial change in the permeability somewhere in the medium. The two possible sequences, liquid-liquid dominated-dry, or liquid-vapor dominated-dry find applications in geothermal systems. Finally, it is shown that although weak heterogeneity affects only gravity controlled flows, stronger variations in permeability can give rise to significant capillary effects.

Proposed method to estimate the liquid-vapor accommodation coefficient based on experimental sonoluminescence data.

PubMed

Puente, Gabriela F; Bonetto, Fabián J

2005-05-01

We used the temporal evolution of the bubble radius in single-bubble sonoluminescence to estimate the water liquid-vapor accommodation coefficient. The rapid changes in the bubble radius that occur during the bubble collapse and rebounds are a function of the actual value of the accommodation coefficient. We selected bubble radius measurements obtained from two different experimental techniques in conjunction with a robust parameter estimation strategy and we obtained that for water at room temperature the mass accommodation coefficient is in the confidence interval [0.217,0.329].

Water Vapor Over Europa

NASA Image and Video Library

2013-12-12

This graphic shows the location of water vapor detected over Europa south pole in observations taken by NASA Hubble Space Telescope in December 2012. This is the first strong evidence of water plumes erupting off Europa surface.

Polymer formulation for removing hydrogen and liquid water from an enclosed space

DOEpatents

Shepodd, Timothy J [Livermore, CA

2006-02-21

This invention describes a solution to the particular problem of liquid water formation in hydrogen getters exposed to quantities of oxygen. Water formation is usually desired because the recombination reaction removes hydrogen without affecting gettering capacity and the oxygen removal reduces the chances for a hydrogen explosion once free oxygen is essentially removed. The present invention describes a getter incorporating a polyacrylate compound that can absorb up to 500% of its own weight in liquid water without significantly affecting its hydrogen gettering/recombination properties, but that also is insensitive to water vapor.

Constructing a superhydrophobic surface on polydimethylsiloxane via spin coating and vapor-liquid sol-gel process.

PubMed

Peng, Yu-Ting; Lo, Kuo-Feng; Juang, Yi-Je

2010-04-06

In this study, a superhydrophobic surface on polydimethylsiloxane (PDMS) substrate was constructed via the proposed vapor-liquid sol-gel process in conjunction with spin coating of dodecyltrichlorosilane (DTS). Unlike the conventional sol-gel process where the reaction takes place in the liquid phase, layers of silica (SiO(2)) particles were formed through the reaction between the reactant spin-coated on the PDMS surface and vapor of the acid solution. This led to the SiO(2) particles inlaid on the PDMS surface. Followed by subsequent spin coating of DTS solution, the wrinkle-like structure was formed, and the static contact angle of the water droplet on the surface could reach 162 degrees with 2 degrees sliding angle and less than 5 degrees contact angle hysteresis. The effect of layers of SiO(2) particles, concentrations of DTS solution and surface topography on superhydrophobicity of the surface is discussed.

First-order wetting transition at a liquid-vapor interface

NASA Technical Reports Server (NTRS)

Schmidt, J. W.; Moldover, M. R.

1983-01-01

Evidence from reflectance and contact angle measurements is presented that three-phase mixtures of i-C3H7OH-C7F14 exhibit a first-order wetting phase transition at the liquid-vapor interface at 38 C. Equilibration phenomena support this interpretation. Ellipsometry was used to measure the apparent thickness of the intruding layer in the three-phase mixture. At temperatures slightly above the wetting temperature T(w), the intruding layer's thickness is several hundred angstroms and its variation with temperature is extremely weak. Below T(w), three-phase contact can occur between the vapor and both the upper and lower liquid phases; one of the angles which characterizes this contact has a very simple temperature dependence. The thickness of the intruding layer, monitored as the solutions approached equilibrium, is found to depend quite weakly on the height spanned by the upper liquid phase in the vicinity of a first-order wetting transition.

Multiphase, multicomponent parameter estimation for liquid and vapor fluxes in deep arid systems using hydrologic data and natural environmental tracers

USGS Publications Warehouse

Kwicklis, Edward M.; Wolfsberg, Andrew V.; Stauffer, Philip H.; Walvoord, Michelle Ann; Sully, Michael J.

2006-01-01

Multiphase, multicomponent numerical models of long-term unsaturated-zone liquid and vapor movement were created for a thick alluvial basin at the Nevada Test Site to predict present-day liquid and vapor fluxes. The numerical models are based on recently developed conceptual models of unsaturated-zone moisture movement in thick alluvium that explain present-day water potential and tracer profiles in terms of major climate and vegetation transitions that have occurred during the past 10 000 yr or more. The numerical models were calibrated using borehole hydrologic and environmental tracer data available from a low-level radioactive waste management site located in a former nuclear weapons testing area. The environmental tracer data used in the model calibration includes tracers that migrate in both the liquid and vapor phases (??D, ??18O) and tracers that migrate solely as dissolved solutes (Cl), thus enabling the estimation of some gas-phase as well as liquid-phase transport parameters. Parameter uncertainties and correlations identified during model calibration were used to generate parameter combinations for a set of Monte Carlo simulations to more fully characterize the uncertainty in liquid and vapor fluxes. The calculated background liquid and vapor fluxes decrease as the estimated time since the transition to the present-day arid climate increases. However, on the whole, the estimated fluxes display relatively little variability because correlations among parameters tend to create parameter sets for which changes in some parameters offset the effects of others in the set. Independent estimates on the timing since the climate transition established from packrat midden data were essential for constraining the model calibration results. The study demonstrates the utility of environmental tracer data in developing numerical models of liquid- and gas-phase moisture movement and the importance of considering parameter correlations when using Monte Carlo analysis to

Water vapor measurements in- and outside cirrus with the novel water vapor mass spectrometer AIMS-H2O

NASA Astrophysics Data System (ADS)

Kaufmann, Stefan; Schlage, Romy; Voigt, Christiane; Jurkat, Tina; Krämer, Martina; Rolf, Christian; Zöger, Martin; Schäfler, Andreas; Dörnbrack, Andreas

2015-04-01

Water vapor plays a crucial role for the earth's climate both directly via its radiative properties and indirectly due to its ability to form clouds. However, accurate measurements of especially low water vapor concentrations prevalent in the upper troposphere and lower stratosphere are difficult and exhibit large discrepancies between different instruments and methods. In order to address this issue and to provide a comprehensive water vapor data set necessary to gather a complete picture of cloud formation processes, four state-of-the-art hygrometers including the novel water vapor mass spectrometer AIMS-H2O were deployed on the DLR research aircraft HALO during the ML-Cirrus campaign in March/April 2014 over Europe. Here, we present first water vapor measurements of AIMS-H2O on HALO. The instrument performance is validated by intercomparison with the fluorescence hygrometer FISH and the laser hygrometer SHARC, both also mounted in the aircraft. This intercomparison shows good agreement between the instruments from low stratospheric mixing ratios up to higher H2O concentrations at upper tropospheric conditions. Gathering data from over 24 flight hours, no significant offsets between the instruments were found (mean of relative deviation

Surface vibrational structure at alkane liquid/vapor interfaces

NASA Astrophysics Data System (ADS)

Esenturk, Okan; Walker, Robert A.

2006-11-01

Broadband vibrational sum frequency spectroscopy (VSFS) has been used to examine the surface structure of alkane liquid/vapor interfaces. The alkanes range in length from n-nonane (C9H20) to n-heptadecane (C17H36), and all liquids except heptadecane are studied at temperatures well above their bulk (and surface) freezing temperatures. Intensities of vibrational bands in the CH stretching region acquired under different polarization conditions show systematic, chain length dependent changes. Data provide clear evidence of methyl group segregation at the liquid/vapor interface, but two different models of alkane chain structure can predict chain length dependent changes in band intensities. Each model leads to a different interpretation of the extent to which different chain segments contribute to the anisotropic interfacial region. One model postulates that changes in vibrational band intensities arise solely from a reduced surface coverage of methyl groups as alkane chain length increases. The additional methylene groups at the surface must be randomly distributed and make no net contribution to the observed VSF spectra. The second model considers a simple statistical distribution of methyl and methylene groups populating a three dimensional, interfacial lattice. This statistical picture implies that the VSF signal arises from a region extending several functional groups into the bulk liquid, and that the growing fraction of methylene groups in longer chain alkanes bears responsibility for the observed spectral changes. The data and resulting interpretations provide clear benchmarks for emerging theories of molecular structure and organization at liquid surfaces, especially for liquids lacking strong polar ordering.

Saturated liquid density of 1,1-difluoroethane(R 152a) and thermodynamic properties along the vapor-liquid coexistence curve

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

Sato, H.; Okada, M.; Uematsu, M.

1987-01-01

Saturated liquid densities of 1,1-difluoroethane (CH/sub 3/CHF/sub 2/) are measured at temperatures from 223 K to 363 K with the estimated uncertainty of +-0.2% by a magnetic densimetry. The experimental results are compared with the available experimental data and some correlations and equations of state. A simple correlation for the saturated liquid density is developed as a function of temperature. This correlation covers the temperature range up to the critical point which reproduces the present experimental results with the percent means deviation of 0.11%. Adding the available experimental data with respect to the vapor pressure, critical parameters, saturated vapor density,more » and the second virial coefficient to the present saturated liquid density data, the parameters of the Redlich-Kwong-Soave equation of state are determined and the thermodynamic properties along the vapor-liquid coexistence curve are derived.« less

Profiling of Atmospheric Water Vapor from the SSM/T-2 Radiometric Measurements

NASA Technical Reports Server (NTRS)

Wang, J. R.

2000-01-01

An advantage of using the millimeter-wave measurements for water vapor profiling is the ability to probe beyond a moderate cloud cover. Such a capability has been demonstrated from an airborne MIR (Millimeter-wave Imaging Radiometer) flight over the Pacific Ocean during an intense observation period of TOGA/COARE (Tropical Ocean Global Atmosphere/ Couple Ocean Atmospheric Response Experiment) in early 1993. A Cloud Lidar System (CLS) and MODIS Airborne Simulator (MAS) were on board the same aircraft to identify the presence of clouds and cloud type. The retrieval algorithm not only provides output of a water vapor profile, but also the cloud liquid water and approximate cloud altitude required to satisfy convergence of the retrieval. The validity of these cloud parameters has not been verified previously. In this document, these cloud parameters are compared with those derived from concurrent measurements from the CLS and AMPR (Advanced Microwave Precipitation Radiometer).

Buoyancy effects on the vapor condensation rate on a horizontal liquid surface

NASA Technical Reports Server (NTRS)

Hasan, Mohammad M.; Lin, Chin-Shun

1989-01-01

The results are presented of a numerical study of the effects of buoyancy on the direct condensation of saturated or nearly saturated vapor on a horizontal liquid surface in a cylindrical tank. The liquid motion beneath the liquid-vapor interface is induced by an axisymmetric laminar jet of subcooled liquid. Analysis and numerical results show that the dominant parameter which determines the influence of buoyancy on the condensation rate is the Richardson number. However, the effect of buoyancy on the condensation rate cannot be quantified in terms of the Richardson number alone. The critical value of the Richardson number below which the condensation rate is not significantly reduced depends on the Reynolds number as well as the Prandtl number.

Evaluation of the Antibacterial Potential of Liquid and Vapor Phase Phenolic Essential Oil Compounds against Oral Microorganisms

PubMed Central

Wu, Chi-Hao; Ko, Shun-Yao; Chen, Michael Yuanchien; Shih, Yin-Hua; Shieh, Tzong-Ming; Chuang, Li-Chuan; Wu, Ching-Yi

2016-01-01

The aim of the present study was to determine the antibacterial activities of the phenolic essential oil (EO) compounds hinokitiol, carvacrol, thymol, and menthol against oral pathogens. Aggregatibacter actinomycetemcomitans, Streptococcus mutans, Methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia. coli were used in this study. The minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), bacterial growth curves, temperature and pH stabilities, and synergistic effects of the liquid and vapor EO compounds were tested. The MIC/MBC of the EO compounds, ranging from the strongest to weakest, were hinokitiol (40–60 μg/mL/40-100 μg/mL), thymol (100–200 μg/mL/200-400 μg/mL), carvacrol (200–400 μg/mL/200-600 μg/mL), and menthol (500-more than 2500 μg/mL/1000-more than 2500 μg/mL). The antibacterial activities of the four EO phenolic compound based on the agar diffusion test and bacterial growth curves showed that the four EO phenolic compounds were stable under different temperatures for 24 h, but the thymol activity decreased when the temperature was higher than 80°C. The combination of liquid carvacrol with thymol did not show any synergistic effects. The activities of the vaporous carvacrol and thymol were inhibited by the presence of water. Continual violent shaking during culture enhanced the activity of menthol. Both liquid and vaporous hinokitiol were stable at different temperatures and pH conditions. The combination of vaporous hinokitiol with zinc oxide did not show synergistic effects. These results showed that the liquid and vapor phases of hinokitiol have strong anti-oral bacteria abilities. Hinokitiol has the potential to be applied in oral health care products, dental materials, and infection controls to exert antimicrobial activity. PMID:27681039

Preprototype vapor compression distillation subsystem. [recovering potable water from wastewater

NASA Technical Reports Server (NTRS)

Ellis, G. S.; Wynveen, R. A.; Schubert, F. H.

1979-01-01

A three-person capacity preprototype vapor compression distillation subsystem for recovering potable water from wastewater aboard spacecraft was designed, assembled, and tested. The major components of the subsystem are: (1) a distillation unit which includes a compressor, centrifuge, central shaft, and outer shell; (2) a purge pump; (3) a liquids pump; (4) a post-treat cartridge; (5) a recycle/filter tank; (6) an evaporator high liquid level sensor; and (7) the product water conductivity monitor. A computer based control monitor instrumentation carries out operating mode change sequences, monitors and displays subsystem parameters, maintains intramode controls, and stores and displays fault detection information. The mechanical hardware occupies 0.467 m3, requires 171 W of electrical power, and has a dry weight of 143 kg. The subsystem recovers potable water at a rate of 1.59 kg/hr, which is equivalent to a duty cycle of approximately 30% for a crew of three. The product water has no foul taste or odor. Continued development of the subsystem is recommended for reclaiming water for human consumption as well as for flash evaporator heat rejection, urinal flushing, washing, and other on-board water requirements.

Motion of liquid plugs between vapor bubbles in capillary tubes: a comparison between fluids

NASA Astrophysics Data System (ADS)

Bertossi, Rémi; Ayel, Vincent; Mehta, Balkrishna; Romestant, Cyril; Bertin, Yves; Khandekar, Sameer

2017-11-01

Pulsating heat pipes (PHP) are now well-known devices in which liquid/vapor slug flow oscillates in a capillary tube wound between hot and cold sources. In this context, this paper focuses on the motion of the liquid plug, trapped between vapor bubbles, moving in capillary tubes, to try to better understand the thermo-physical phenomena involved in such devices. This study is divided into three parts. In the first part, an experimental study presents the evolution of the vapor pressure during the evaporation process of a liquid thin film deposited from a liquid plug flowing in a heated capillary tube: it is found that the behavior of the generated and removed vapor can be very different, according to the thermophysical properties of the fluids. In the second part, a transient model allows to compare, in terms of pressure and duration, the motion of a constant-length liquid plug trapped between two bubbles subjected to a constant difference of vapor pressure: the results highlight that the performances of the four fluids are also very different. Finally, a third model that can be considered as an improvement of the second one, is also presented: here, the liquid slug is surrounded by two vapor bubbles, one subjected to evaporation, the pressure in both bubbles is now a result of the calculation. This model still allows comparing the behaviors of the fluid. Even if our models are quite far from a complete model of a real PHP, results do indicate towards the applicability of different fluids as suitable working fluids for PHPs, particularly in terms of the flow instabilities which they generate.

Vacuum distillation/vapor filtration water recovery

NASA Technical Reports Server (NTRS)

Honegger, R. J.; Neveril, R. B.; Remus, G. A.

1974-01-01

The development and evaluation of a vacuum distillation/vapor filtration (VD/VF) water recovery system are considered. As a functional model, the system converts urine and condensates waste water from six men to potable water on a steady-state basis. The system is designed for 180-day operating durations and for function on the ground, on zero-g aircraft, and in orbit. Preparatory tasks are summarized for conducting low gravity tests of a vacuum distillation/vapor filtration system for recovering water from urine.

Temperature Dependence and Energetics of Single Ions at the Aqueous Liquid-Vapor Interface

PubMed Central

Ou, Shuching; Patel, Sandeep

2014-01-01

We investigate temperature-dependence of free energetics with two single halide anions, I− and Cl−, crossing the aqueous liquid-vapor interface through molecular dynamics simulations. The result shows that I− has a modest surface stability of 0.5 kcal/mol at 300 K and the stability decreases as the temperature increases, indicating the surface adsorption process for the anion is entropically disfavored. In contrast, Cl− shows no such surface state at all temperatures. Decomposition of free energetics reveals that water-water interactions provide a favorable enthalpic contribution, while the desolvation of ion induces an increase in free energy. Calculations of surface fluctuations demonstrate that I− generates significantly greater interfacial fluctuations compared to Cl−. The fluctuation is attributed to the malleability of the solvation shells, which allows for more long-ranged perturbations and solvent density redistribution induced by I− as the anion approaches the liquid-vapor interface. The increase in temperature of the solvent enhances the inherent thermally-excited fluctuations and consequently reduces the relative contribution from anion to surface fluctuations, which is consistent with the decrease in surface-stability of I−. Our results indicate a strong correlation with induced interfacial fluctuations and anion surface stability; moreover, resulting temperature dependent behavior of induced fluctuations suggests the possibility of a critical level of induced fluctuations associated with surface stability. PMID:23537166

Using Dalton's Law of Partial Pressures to Determine the Vapor Pressure of a Volatile Liquid

ERIC Educational Resources Information Center

Hilgeman, Fred R.; Bertrand, Gary; Wilson, Brent

2007-01-01

This experiment, designed for a general chemistry laboratory, illustrates the use of Dalton's law of partial pressures to determine the vapor pressure of a volatile liquid. A predetermined volume of air is injected into a calibrated tube filled with a liquid whose vapor pressure is to be measured. The volume of the liquid displaced is greater than…

Liquid-vapor interface locations in a spheroidal container under low gravity

NASA Technical Reports Server (NTRS)

Carney, M. J.

1986-01-01

As a part of the general study of liquid behavior in low gravity environments, an experimental investigation was conducted to determine if there are equilibrium liquid-vapor interface configurations that can exist at more than one location in oblate spheroidal containers under reduced gravity conditions. Static contact angles of the test liquids on the spheroid surface were restricted to near 0 deg. The experiments were conducted in a low gravity environment. An oblate spheroidal tank was tested with an eccentricity of 0.68 and a semimajor axis of 2.0 cm. Both quantitative and qualitative data were obtained on the liquid-vapor interface configuration and position inside the container. The results of these data, and their impat on previous work in this area, are discussed. Of particular interest are those equilibrium interface configurations that can exist at multiple locations in the container.

Water Vapor Remote Sensing Techniques: Radiometry and Solar Spectrometry

NASA Astrophysics Data System (ADS)

Somieski, A.; Buerki, B.; Cocard, M.; Geiger, A.; Kahle, H.-G.

The high variability of atmospheric water vapor content plays an important role in space geodesy, climatology and meteorology. Water vapor has a strong influence on transatmospheric satellite signals, the Earth's climate and thus the weather forecasting. Several remote sensing techniques have been developed for the determination of inte- grated precipitable water vapor (IPWV). The Geodesy and Geodynamics Lab (GGL) utilizes the methods of Water Vapor Radiometry and Solar Spectrometry to quantify the amount of tropospheric water vapor and its temporal variations. The Water Vapor Radiometer (WVR) measures the radiation intensity of the atmosphere in a frequency band ranging from 20 to 32 GHz. The Solar Atmospheric MOnitoring Spectrome- ter (SAMOS) of GGL is designed for high-resolution measurements of water vapor absorption lines using solar radiation. In the framework of the ESCOMPTE (ExpÊrience sur Site pour COntraindre les Mod- Éles de Pollution atmosphÊrique et de Transport d'Emissions) field campaign these instruments have been operated near Marseille in 2001. They have aquired a long time series of integrated precipitable water vapor content (IPWV). The accuracy of IPWV measured by WVR and SAMOS is 1 kg/m2. Furthermore meteorological data from radiosondes were used to calculate the IPWV in order to provide comparisons with the results of WVR and SAMOS. The methods of Water Vapor Radiometry and So- lar Spectrometry will be discussed and first preliminary results retrieved from WVR, SAMOS and radiosondes during the ESCOMPTE field campaign will be presented.

PROGRESS REPORT OF FY 2004 ACTIVITIES: IMPROVED WATER VAPOR AND CLOUD RETRIEVALS AT THE NSA/AAO

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

E. R. Westwater; V. V. Leuskiy; M. Klein

2004-11-01

The basic goals of the research are to develop and test algorithms and deploy instruments that improve measurements of water vapor, cloud liquid, and cloud coverage, with a focus on the Arctic conditions of cold temperatures and low concentrations of water vapor. The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement Program. Although several technologies have been investigated to measure these column amounts, microwave radiometers (MWR) have been used operationally by the ARM program for passive retrievals of these quantities: precipitable water vapor (PWV)more » and integrated water liquid (IWL). The technology of PWV and IWL retrievals has advanced steadily since the basic 2-channel MWR was first deployed at ARM CART sites Important advances are the development and refinement of the tipcal calibration method [1,2], and improvement of forward model radiative transfer algorithms [3,4]. However, the concern still remains that current instruments deployed by ARM may be inadequate to measure low amounts of PWV and IWL. In the case of water vapor, this is especially important because of the possibility of scaling and/or quality control of radiosondes by the water amount. Extremely dry conditions, with PWV less than 3 mm, commonly occur in Polar Regions during the winter months. Accurate measurements of the PWV during such dry conditions are needed to improve our understanding of the regional radiation energy budgets. The results of a 1999 experiment conducted at the ARM North Slope of Alaska/Adjacent Arctic Ocean (NSA/AAO) site during March of 1999 [5] have shown that the strength associated with the 183 GHz water vapor absorption line makes radiometry in this frequency regime suitable for measuring low amounts of PWV. As a portion of our research, we conducted another millimeter wave radiometric experiment at the NSA/AAO in March-April 2004. This

40 CFR 63.1027 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards § 63.1027 Connectors in gas and vapor service and in light liquid service standards. (a..., the owner or operator shall monitor all connectors in gas and vapor and light liquid service as... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Connectors in gas and vapor service...

40 CFR 63.1027 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards § 63.1027 Connectors in gas and vapor service and in light liquid service standards. (a..., the owner or operator shall monitor all connectors in gas and vapor and light liquid service as... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Connectors in gas and vapor service...

40 CFR 63.1027 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Standards § 63.1027 Connectors in gas and vapor service and in light liquid service standards. (a..., the owner or operator shall monitor all connectors in gas and vapor and light liquid service as... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Connectors in gas and vapor service...

40 CFR 63.1027 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Standards § 63.1027 Connectors in gas and vapor service and in light liquid service standards. (a..., the owner or operator shall monitor all connectors in gas and vapor and light liquid service as... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Connectors in gas and vapor service...

40 CFR 63.1027 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Standards § 63.1027 Connectors in gas and vapor service and in light liquid service standards. (a..., the owner or operator shall monitor all connectors in gas and vapor and light liquid service as... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Connectors in gas and vapor service...

Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation and Condensation at a Liquid Vapor Interface

NASA Technical Reports Server (NTRS)

Stewart, Mark

2017-01-01

Evaporation and condensation at a liquid-vapor interface is important for long-term, in-space cryogenic propellant storage. Yet the current understanding of inter-facial physics does not consistently predict behavior of evaporation or condensation rates. The proposed paper will present a physical model, based on the 1-D Heat equation and Schrage's equation, which demonstrates thin thermal layers at the fluid vapor interface.

Thermal-hydraulic behaviors of vapor-liquid interface due to arrival of a pressure wave

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

Inoue, Akira; Fujii, Yoshifumi; Matsuzaki, Mitsuo

In the vapor explosion, a pressure wave (shock wave) plays a fundamental role for triggering, propagation and enhancement of the explosion. Energy of the explosion is related to the magnitude of heat transfer rate from hot liquid to cold volatile one. This is related to an increasing rate of interface area and to an amount of transient heat flux between the liquids. In this study, the characteristics of transient heat transfer and behaviors of vapor film both on the platinum tube and on the hot melt tin drop, under same boundary conditions have been investigated. It is considered that theremore » exists a fundamental mechanism of the explosion in the initial expansion process of the hot liquid drop immediately after arrival of pressure wave. The growth rate of the vapor film is much faster on the hot liquid than that on the solid surface. Two kinds of roughness were observed, one due to the Taylor instability, by rapid growth of the explosion bubble, and another, nucleation sites were observed at the vapor-liquid interface. Based on detailed observation of early stage interface behaviors after arrival of a pressure wave, the thermal fragmentation mechanism is proposed.« less

Predicting vapor-liquid phase equilibria with augmented ab initio interatomic potentials

NASA Astrophysics Data System (ADS)

Vlasiuk, Maryna; Sadus, Richard J.

2017-06-01

The ability of ab initio interatomic potentials to accurately predict vapor-liquid phase equilibria is investigated. Monte Carlo simulations are reported for the vapor-liquid equilibria of argon and krypton using recently developed accurate ab initio interatomic potentials. Seventeen interatomic potentials are studied, formulated from different combinations of two-body plus three-body terms. The simulation results are compared to either experimental or reference data for conditions ranging from the triple point to the critical point. It is demonstrated that the use of ab initio potentials enables systematic improvements to the accuracy of predictions via the addition of theoretically based terms. The contribution of three-body interactions is accounted for using the Axilrod-Teller-Muto plus other multipole contributions and the effective Marcelli-Wang-Sadus potentials. The results indicate that the predictive ability of recent interatomic potentials, obtained from quantum chemical calculations, is comparable to that of accurate empirical models. It is demonstrated that the Marcelli-Wang-Sadus potential can be used in combination with accurate two-body ab initio models for the computationally inexpensive and accurate estimation of vapor-liquid phase equilibria.

Predicting vapor-liquid phase equilibria with augmented ab initio interatomic potentials.

PubMed

Vlasiuk, Maryna; Sadus, Richard J

2017-06-28

The ability of ab initio interatomic potentials to accurately predict vapor-liquid phase equilibria is investigated. Monte Carlo simulations are reported for the vapor-liquid equilibria of argon and krypton using recently developed accurate ab initio interatomic potentials. Seventeen interatomic potentials are studied, formulated from different combinations of two-body plus three-body terms. The simulation results are compared to either experimental or reference data for conditions ranging from the triple point to the critical point. It is demonstrated that the use of ab initio potentials enables systematic improvements to the accuracy of predictions via the addition of theoretically based terms. The contribution of three-body interactions is accounted for using the Axilrod-Teller-Muto plus other multipole contributions and the effective Marcelli-Wang-Sadus potentials. The results indicate that the predictive ability of recent interatomic potentials, obtained from quantum chemical calculations, is comparable to that of accurate empirical models. It is demonstrated that the Marcelli-Wang-Sadus potential can be used in combination with accurate two-body ab initio models for the computationally inexpensive and accurate estimation of vapor-liquid phase equilibria.

Water Vapor Corrosion in EBC Constituent Materials

NASA Technical Reports Server (NTRS)

Kowalski, Benjamin; Fox, Dennis; Jacobson, Nathan S.

2017-01-01

Environmental Barrier Coating (EBC) materials are sought after to protect ceramic matrix composites (CMC) in high temperature turbine engines. CMCs are particularly susceptible to degradation from oxidation, Ca-Al-Mg-Silicate (CMAS), and water vapor during high temperature operation which necessitates the use of EBCs. However, the work presented here focuses on water vapor induced recession in EBC constituent materials. For example, in the presence of water vapor, silica will react to form Si(OH)4 (g) which will eventually corrode the material away. To investigate the recession rate in EBC constituent materials under high temperature water vapor conditions, thermal gravimetric analysis (TGA) is employed. The degradation process can then be modeled through a simple boundary layer expression. Ultimately, comparisons are made between various single- and poly-crystalline materials (e.g. TiO2, SiO2) against those found in literature.

40 CFR 63.1006 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... § 63.1006 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... requested by the Administrator. For each such demonstration, all valves in gas and vapor and light liquid... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Valves in gas and vapor service and in...

40 CFR 63.1006 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... § 63.1006 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... requested by the Administrator. For each such demonstration, all valves in gas and vapor and light liquid... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Valves in gas and vapor service and in...

40 CFR 63.1006 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... § 63.1006 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... requested by the Administrator. For each such demonstration, all valves in gas and vapor and light liquid... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Valves in gas and vapor service and in...

40 CFR 63.1006 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... § 63.1006 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... requested by the Administrator. For each such demonstration, all valves in gas and vapor and light liquid... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Valves in gas and vapor service and in...

40 CFR 63.1006 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 63.1006 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... requested by the Administrator. For each such demonstration, all valves in gas and vapor and light liquid... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Valves in gas and vapor service and in...

Water vapor radiometry research and development phase

NASA Technical Reports Server (NTRS)

Resch, G. M.; Chavez, M. C.; Yamane, N. L.; Barbier, K. M.; Chandlee, R. C.

1985-01-01

This report describes the research and development phase for eight dual-channel water vapor radiometers constructed for the Crustal Dynamics Project at the Goddard Space Flight Center, Greenbelt, Maryland, and for the NASA Deep Space Network. These instruments were developed to demonstrate that the variable path delay imposed on microwave radio transmissions by atmospheric water vapor can be calibrated, particularly as this phenomenon affects very long baseline interferometry measurement systems. Water vapor radiometry technology can also be used in systems that involve moist air meteorology and propagation studies.

40 CFR 63.649 - Alternative means of emission limitation: Connectors in gas/vapor service and light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... limitation: Connectors in gas/vapor service and light liquid service. 63.649 Section 63.649 Protection of...: Connectors in gas/vapor service and light liquid service. (a) If an owner or operator elects to monitor... gas/vapor service and for connectors in light liquid service. The data for the two groups of...

40 CFR 63.649 - Alternative means of emission limitation: Connectors in gas/vapor service and light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... limitation: Connectors in gas/vapor service and light liquid service. 63.649 Section 63.649 Protection of...: Connectors in gas/vapor service and light liquid service. (a) If an owner or operator elects to monitor... gas/vapor service and for connectors in light liquid service. The data for the two groups of...

40 CFR 63.649 - Alternative means of emission limitation: Connectors in gas/vapor service and light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... limitation: Connectors in gas/vapor service and light liquid service. 63.649 Section 63.649 Protection of...: Connectors in gas/vapor service and light liquid service. (a) If an owner or operator elects to monitor... gas/vapor service and for connectors in light liquid service. The data for the two groups of...

40 CFR 63.649 - Alternative means of emission limitation: Connectors in gas/vapor service and light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... limitation: Connectors in gas/vapor service and light liquid service. 63.649 Section 63.649 Protection of...: Connectors in gas/vapor service and light liquid service. (a) If an owner or operator elects to monitor... gas/vapor service and for connectors in light liquid service. The data for the two groups of...

40 CFR 63.649 - Alternative means of emission limitation: Connectors in gas/vapor service and light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... limitation: Connectors in gas/vapor service and light liquid service. 63.649 Section 63.649 Protection of...: Connectors in gas/vapor service and light liquid service. (a) If an owner or operator elects to monitor... gas/vapor service and for connectors in light liquid service. The data for the two groups of...

40 CFR 60.482-7 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Before November 7, 2006 § 60.482-7 Standards: Valves in gas/vapor service and in light liquid service. (a... operation in gas/vapor service or light liquid service after the initial startup date for the process unit... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards: Valves in gas/vapor service...

40 CFR 60.482-7 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Before November 7, 2006 § 60.482-7 Standards: Valves in gas/vapor service and in light liquid service. (a... operation in gas/vapor service or light liquid service after the initial startup date for the process unit... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service...

40 CFR 60.482-7 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Before November 7, 2006 § 60.482-7 Standards: Valves in gas/vapor service and in light liquid service. (a... operation in gas/vapor service or light liquid service after the initial startup date for the process unit... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards: Valves in gas/vapor service...

40 CFR 60.482-7 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Before November 7, 2006 § 60.482-7 Standards: Valves in gas/vapor service and in light liquid service. (a... operation in gas/vapor service or light liquid service after the initial startup date for the process unit... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards: Valves in gas/vapor service...

40 CFR 60.482-7 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Before November 7, 2006 § 60.482-7 Standards: Valves in gas/vapor service and in light liquid service. (a... operation in gas/vapor service or light liquid service after the initial startup date for the process unit... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards: Valves in gas/vapor service...

Prediction of the vapor pressure and vaporization enthalpy of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids.

PubMed

Diedenhofen, Michael; Klamt, Andreas; Marsh, Kenneth; Schäfer, Ansgar

2007-09-07

The vapor pressures and vaporization enthalpies of a series of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids have been predicted with two different approaches using the COSMO-RS method and quantum chemical gas phase calculations. While the calculated enthalpies are in good agreement with the experimental data, COSMO-RS seems to underestimate the vapor pressures by roughly 0.5-4 log units dependent on the IL and approach used.

Climate and Ozone Response to Increased Stratospheric Water Vapor

NASA Technical Reports Server (NTRS)

Shindell, Drew T.

2001-01-01

Stratospheric water vapor abundance affects ozone, surface climate, and stratospheric temperatures. From 30-50 km altitude, temperatures show global decreases of 3-6 K over recent decades. These may be a proxy for water vapor increases, as the Goddard Institute for Space Studies (GISS) climate model reproduces these trends only when stratospheric water vapor is allowed to increase. Observations suggest that stratospheric water vapor is indeed increasing, however, measurements are extremely limited in either spatial coverage or duration. The model results suggest that the observed changes may be part of a global, long-term trend. Furthermore, the required water vapor change is too large to be accounted for by increased production within the stratosphere, suggesting that ongoing climate change may be altering tropospheric input. The calculated stratospheric water vapor increase contributes an additional approximately equals 24% (approximately equals 0.2 W/m(exp 2)) to the global warming from well-mixed greenhouse gases over the past two decades. Observed ozone depletion is also better reproduced when destruction due to increased water vapor is included. If the trend continues, it could increase future global warming and impede stratospheric ozone recovery.

Mountain waves modulate the water vapor distribution in the UTLS

NASA Astrophysics Data System (ADS)

Heller, Romy; Voigt, Christiane; Beaton, Stuart; Dörnbrack, Andreas; Giez, Andreas; Kaufmann, Stefan; Mallaun, Christian; Schlager, Hans; Wagner, Johannes; Young, Kate; Rapp, Markus

2017-12-01

The water vapor distribution in the upper troposphere-lower stratosphere (UTLS) region has a strong impact on the atmospheric radiation budget. Transport and mixing processes on different scales mainly determine the water vapor concentration in the UTLS. Here, we investigate the effect of mountain waves on the vertical transport and mixing of water vapor. For this purpose we analyze measurements of water vapor and meteorological parameters recorded by the DLR Falcon and NSF/NCAR Gulfstream V research aircraft taken during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) in New Zealand. By combining different methods, we develop a new approach to quantify location, direction and irreversibility of the water vapor transport during a strong mountain wave event on 4 July 2014. A large positive vertical water vapor flux is detected above the Southern Alps extending from the troposphere to the stratosphere in the altitude range between 7.7 and 13.0 km. Wavelet analysis for the 8.9 km altitude level shows that the enhanced upward water vapor transport above the mountains is caused by mountain waves with horizontal wavelengths between 22 and 60 km. A downward transport of water vapor with 22 km wavelength is observed in the lee-side of the mountain ridge. While it is a priori not clear whether the observed fluxes are irreversible, low Richardson numbers derived from dropsonde data indicate enhanced turbulence in the tropopause region related to the mountain wave event. Together with the analysis of the water vapor to ozone correlation, we find indications for vertical transport followed by irreversible mixing of water vapor. For our case study, we further estimate greater than 1 W m-2 radiative forcing by the increased water vapor concentrations in the UTLS above the Southern Alps of New Zealand, resulting from mountain waves relative to unperturbed conditions. Hence, mountain waves have a great potential to affect the water vapor distribution in the UTLS. Our

Solute rotational dynamics at the water liquid/vapor interface.

PubMed

Benjamin, Ilan

2007-11-28

The rotational dynamics of a number of diatomic molecules adsorbed at different locations at the interface between water and its own vapors are studied using classical molecular dynamics computer simulations. Both equilibrium orientational and energy correlations and nonequilibrium orientational and energy relaxation correlations are calculated. By varying the dipole moment of the molecule and its location, and by comparing the results with those in bulk water, the effects of dielectric and mechanical frictions on reorientation dynamics and on rotational energy relaxation can be studied. It is shown that for nonpolar and weekly polar solutes, the equilibrium orientational relaxation is much slower in the bulk than at the interface. As the solute becomes more polar, the rotation slows down and the surface and bulk dynamics become similar. The energy relaxation (both equilibrium and nonequilibrium) has the opposite trend with the solute dipole (larger dipoles relax faster), but here again the bulk and surface results converge as the solute dipole is increased. It is shown that these behaviors correlate with the peak value of the solvent-solute radial distribution function, which demonstrates the importance of the first hydration shell structure in determining the rotational dynamics and dependence of these dynamics on the solute dipole and location.

Profiling of Atmospheric Water Vapor with MIR and LASE

NASA Technical Reports Server (NTRS)

Wang, J. R.; Racette, P.; Triesly, M. E.; Browell, E. V.; Ismail, S.; Chang, L. A.; Hildebrand, Peter H. (Technical Monitor)

2001-01-01

This paper presents the first and the only simultaneous measurements of water vapor by MIR (Millimeter-wave Imaging Radiometer) and LASE (Lidar Atmospheric Sounding Experiment) on board the same ER-2 aircraft. Water vapor is one of the most important constituents in the Earth's atmosphere, as its spatial and temporal variations affect a wide spectrum of meteorological phenomena ranging from the formation of clouds to the development of severe storms. Its concentration, as measured in terms of relative humidity, determines the extinction coefficient of atmospheric aerosol particles and therefore visibility. These considerations point to the need for effective and frequent measurements of the atmospheric water vapor. The MIR and LASE instruments provide measurements of water vapor profiles with two markedly different techniques. LASE can give water vapor profiles with excellent vertical resolution under clear condition, while MIR can retrieve water vapor profiles with a crude vertical resolution even under a moderate cloud cover. Additionally, millimeter-wave measurements are relatively simple and provide better spatial coverage.

The Foundation GPS Water Vapor Inversion and its Application Research

NASA Astrophysics Data System (ADS)

Liu, R.; Lee, T.; Lv, H.; Fan, C.; Liu, Q.

2018-04-01

Using GPS technology to retrieve atmospheric water vapor is a new water vapor detection method, which can effectively compensate for the shortcomings of conventional water vapor detection methods, to provide high-precision, large-capacity, near real-time water vapor information. In-depth study of ground-based GPS detection of atmospheric water vapor technology aims to further improve the accuracy and practicability of GPS inversion of water vapor and to explore its ability to detect atmospheric water vapor information to better serve the meteorological services. In this paper, the influence of the setting parameters of initial station coordinates, satellite ephemeris and solution observation on the total delay accuracy of the tropospheric zenith is discussed based on the observed data. In this paper, the observations obtained from the observation network consisting of 8 IGS stations in China in June 2013 are used to inverse the water vapor data of the 8 stations. The data of Wuhan station is further selected and compared with the data of Nanhu Sounding Station in Wuhan The error between the two data was between -6mm-6mm, and the trend of the two was almost the same, the correlation reached 95.8 %. The experimental results also verify the reliability of ground-based GPS inversion of water vapor technology.

Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.

PubMed

Tromelin, Anne; Andriot, Isabelle; Kopjar, Mirela; Guichard, Elisabeth

2010-04-14

Thermodynamic parameters (T, DeltaH degrees , DeltaS degrees , K) were collected from the literature and/or calculated for five esters, four ketones, two aldehydes, and three alcohols, pure compounds and compounds in aqueous solution. Examination of correlations between these parameters and the range values of DeltaH degrees and DeltaS degrees puts forward the key roles of enthalpy for vaporization of pure compounds and of entropy in liquid-vapor equilibrium of compounds in aqueous solution. A structure-property relationship (SPR) study was performed using molecular descriptors on aroma compounds to better understand their vaporization behavior. In addition to the role of polarity for vapor-liquid equilibrium of compounds in aqueous solution, the structure-property study points out the role of chain length and branching, illustrated by the correlation between the connectivity index CHI-V-1 and the difference between T and log K for vaporization of pure compounds and compounds in aqueous solution. Moreover, examination of the esters' enthalpy values allowed a probable conformation adopted by ethyl octanoate in aqueous solution to be proposed.

Water vapor movement in freezing aggregate base materials.

DOT National Transportation Integrated Search

2014-06-01

The objectives of this research were to 1) measure the extent to which water vapor movement results in : water accumulation in freezing base materials; 2) evaluate the effect of soil stabilization on water vapor movement : in freezing base materials;...

Passive Vaporizing Heat Sink

NASA Technical Reports Server (NTRS)

Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.

2011-01-01

A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

Active Raman sounding of the earth's water vapor field.

PubMed

Tratt, David M; Whiteman, David N; Demoz, Belay B; Farley, Robert W; Wessel, John E

2005-08-01

The typically weak cross-sections characteristic of Raman processes has historically limited their use in atmospheric remote sensing to nighttime application. However, with advances in instrumentation and techniques, it is now possible to apply Raman lidar to the monitoring of atmospheric water vapor, aerosols and clouds throughout the diurnal cycle. Upper tropospheric and lower stratospheric measurements of water vapor using Raman lidar are also possible but are limited to nighttime and require long integration times. However, boundary layer studies of water vapor variability can now be performed with high temporal and spatial resolution. This paper will review the current state-of-the-art of Raman lidar for high-resolution measurements of the atmospheric water vapor, aerosol and cloud fields. In particular, we describe the use of Raman lidar for mapping the vertical distribution and variability of atmospheric water vapor, aerosols and clouds throughout the evolution of dynamic meteorological events. The ability of Raman lidar to detect and characterize water in the region of the tropopause and the importance of high-altitude water vapor for climate-related studies and meteorological satellite performance are discussed.

Adsorptive Water Removal from Dichloromethane and Vapor-Phase Regeneration of a Molecular Sieve 3A Packed Bed

PubMed Central

2017-01-01

The drying of dichloromethane with a molecular sieve 3A packed bed process is modeled and experimentally verified. In the process, the dichloromethane is dried in the liquid phase and the adsorbent is regenerated by water desorption with dried dichloromethane product in the vapor phase. Adsorption equilibrium experiments show that dichloromethane does not compete with water adsorption, because of size exclusion; the pure water vapor isotherm from literature provides an accurate representation of the experiments. The breakthrough curves are adequately described by a mathematical model that includes external mass transfer, pore diffusion, and surface diffusion. During the desorption step, the main heat transfer mechanism is the condensation of the superheated dichloromethane vapor. The regeneration time is shortened significantly by external bed heating. Cyclic steady-state experiments demonstrate the feasibility of this novel, zero-emission drying process. PMID:28539701

Holographic studies of the vapor explosion of vaporizing water-in-fuel emulsion droplets

NASA Technical Reports Server (NTRS)

Sheffield, S. A.; Hess, C. F.; Trolinger, J. D.

1982-01-01

Holographic studies were performed which examined the fragmentation process during vapor explosion of a water-in-fuel (hexadecane/water) emulsion droplet. Holograms were taken at 700 to 1000 microseconds after the vapor explosion. Photographs of the reconstructed holograms reveal a wide range of fragment droplet sizes created during the explosion process. Fragment droplet diameters range from below 10 microns to over 100 microns. It is estimated that between ten thousand and a million fragment droplets can result from this extremely violent vapor explosion process. This enhanced atomization is thus expected to have a pronounced effect on vaporization processes which are present during combustion of emulsified fuels.

A New Neural Network Approach Including First-Guess for Retrieval of Atmospheric Water Vapor, Cloud Liquid Water Path, Surface Temperature and Emissivities Over Land From Satellite Microwave Observations

NASA Technical Reports Server (NTRS)

Aires, F.; Prigent, C.; Rossow, W. B.; Rothstein, M.; Hansen, James E. (Technical Monitor)

2000-01-01

The analysis of microwave observations over land to determine atmospheric and surface parameters is still limited due to the complexity of the inverse problem. Neural network techniques have already proved successful as the basis of efficient retrieval methods for non-linear cases, however, first-guess estimates, which are used in variational methods to avoid problems of solution non-uniqueness or other forms of solution irregularity, have up to now not been used with neural network methods. In this study, a neural network approach is developed that uses a first-guess. Conceptual bridges are established between the neural network and variational methods. The new neural method retrieves the surface skin temperature, the integrated water vapor content, the cloud liquid water path and the microwave surface emissivities between 19 and 85 GHz over land from SSM/I observations. The retrieval, in parallel, of all these quantities improves the results for consistency reasons. A data base to train the neural network is calculated with a radiative transfer model and a a global collection of coincident surface and atmospheric parameters extracted from the National Center for Environmental Prediction reanalysis, from the International Satellite Cloud Climatology Project data and from microwave emissivity atlases previously calculated. The results of the neural network inversion are very encouraging. The r.m.s. error of the surface temperature retrieval over the globe is 1.3 K in clear sky conditions and 1.6 K in cloudy scenes. Water vapor is retrieved with a r.m.s. error of 3.8 kg/sq m in clear conditions and 4.9 kg/sq m in cloudy situations. The r.m.s. error in cloud liquid water path is 0.08 kg/sq m . The surface emissivities are retrieved with an accuracy of better than 0.008 in clear conditions and 0.010 in cloudy conditions. Microwave land surface temperature retrieval presents a very attractive complement to the infrared estimates in cloudy areas: time record of land

40 CFR 65.108 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Standards: Connectors in gas/vapor service and in light liquid service. (a) Compliance schedule. Except as... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 65.108 Section 65.108 Protection of Environment ENVIRONMENTAL...

40 CFR 65.109 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Standards: Agitators in gas/vapor service and in light liquid service. (a) Compliance schedule. The owner or... 40 Protection of Environment 16 2012-07-01 2012-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 65.109 Section 65.109 Protection of Environment ENVIRONMENTAL...

40 CFR 65.109 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards: Agitators in gas/vapor service and in light liquid service. (a) Compliance schedule. The owner or... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 65.109 Section 65.109 Protection of Environment ENVIRONMENTAL...

40 CFR 65.108 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Standards: Connectors in gas/vapor service and in light liquid service. (a) Compliance schedule. Except as... 40 Protection of Environment 16 2012-07-01 2012-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 65.108 Section 65.108 Protection of Environment ENVIRONMENTAL...

40 CFR 65.109 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards: Agitators in gas/vapor service and in light liquid service. (a) Compliance schedule. The owner or... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 65.109 Section 65.109 Protection of Environment ENVIRONMENTAL...

40 CFR 65.108 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards: Connectors in gas/vapor service and in light liquid service. (a) Compliance schedule. Except as... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 65.108 Section 65.108 Protection of Environment ENVIRONMENTAL...

40 CFR 65.108 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards: Connectors in gas/vapor service and in light liquid service. (a) Compliance schedule. Except as... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 65.108 Section 65.108 Protection of Environment ENVIRONMENTAL...

40 CFR 65.108 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Standards: Connectors in gas/vapor service and in light liquid service. (a) Compliance schedule. Except as... 40 Protection of Environment 16 2013-07-01 2013-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 65.108 Section 65.108 Protection of Environment ENVIRONMENTAL...

40 CFR 65.109 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Standards: Agitators in gas/vapor service and in light liquid service. (a) Compliance schedule. The owner or... 40 Protection of Environment 16 2013-07-01 2013-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 65.109 Section 65.109 Protection of Environment ENVIRONMENTAL...

40 CFR 65.109 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Standards: Agitators in gas/vapor service and in light liquid service. (a) Compliance schedule. The owner or... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 65.109 Section 65.109 Protection of Environment ENVIRONMENTAL...

Stable isotopes in water vapor and precipitation for a coastal lagoon at mid latitudes

NASA Astrophysics Data System (ADS)

Zannoni, Daniele; Bergamasco, Andrea; Dreossi, Giuliano; Rampazzo, Giancarlo; Stenni, Barbara

2016-04-01

The stable oxygen and hydrogen isotope composition in precipitation can be used in hydrology to describe the signature of local meteoric water. The isotopic composition of water vapor is usually obtained indirectly from measurements of δD and δ18O in precipitation, assuming the isotopic equilibrium between rain and water vapor. Only few studies report isotopic data in both phases for the same area, thus providing a complete Local Meteoric Water Line (LMWL). The goal of this study is to build a complete LMWL for the lagoon of Venice (northern Italy) with observations of both water vapor and precipitation. The sampling campaign has started in March 2015 and will be carried out until the end of 2016. Water vapor is collected once a week with cold traps at low temperatures (-77°C). Precipitation is collected on event and monthly basis with a custom automatic rain sampler and a rain gauge, respectively. Liquid samples are analyzed with a Picarro L1102-i and results are reported vs VSMOW. The main meteorological parameters are continuously recorded in the same area by the campus automatic weather station. Preliminary data show an LMWL close to the Global Meteoric Water Line (GMWL) with lower slope and intercept. An evaporation line is clearly recognizable, considering samples that evaporated between the cloud base and the ground. The deviation from the GMWL parameters, especially intercept, can be attributed to evaporated rain or to the humidity conditions of the water vapor source. Water vapor collected during rainfall shows that rain and vapor are near the isotopic equilibrium, just considering air temperature measured at ground level. Temperature is one of the main factor that controls the isotopic composition of the atmospheric water vapor. Nevertheless, the circulation of air masses is a crucial parameter which has to be considered. Water vapor samples collected in different days but with the same meteorological conditions (air temperature and relative humidity

Water vapor recovery from plant growth chambers

NASA Technical Reports Server (NTRS)

Ray, R. J.; Newbold, D. D.; Colton, R. H.; Mccray, S. B.

1991-01-01

NASA is investigating the use of plant growth chambers (PGCs) for space missions and for bases on the moon and Mars. Key to successful development of PGCs is a system to recover and reuse the water vapor that is transpired from the leaves of the plants. A design is presented for a simple, reliable, membrane-based system that allows the recovery, purification, and reuse of the transpired water vapor through control of temperature and humidity levels in PGCs. The system is based on two membrane technologies: (1) dehumidification membrane modules to remove water vapor from the air, and (2) membrane contactors to return water vapor to the PGC (and, in doing so, to control the humidity and temperature within the PGC). The membrane-based system promises to provide an ideal, stable growth environment for a variety of plants, through a design that minimizes energy usage, volume, and mass, while maximizing simplicity and reliability.

Water vapor lidar

NASA Technical Reports Server (NTRS)

Ellingson, R.; Mcilrath, T.; Schwemmer, G.; Wilkerson, T. D.

1976-01-01

The feasibility was studied of measuring atmospheric water vapor by means of a tunable lidar operated from the space shuttle. The specific method evaluated was differential absorption, a two-color method in which the atmospheric path of interest is traversed by two laser pulses. Results are reported.

Mass spectrometry for water vapor measurements in the UT/LS

NASA Astrophysics Data System (ADS)

Kaufmann, S.; Voigt, C.; Schäuble, D.; Schäfler, A.; Schlager, H.; Thornberry, T. D.; Fahey, D. W.

2012-12-01

Water vapor in the lower stratosphere plays a crucial role for the atmospheric radiation budget (Solomon et al., 2011). However, large uncertainties remain in measuring atmospheric water vapor mixing ratios below 10 ppmv typical for the lower stratosphere. To this end, we have developed the Atmospheric Ionization Mass Spectrometer (AIMS) for the accurate and fast detection of water vapor in the UT/LS from aircraft. In the AIMS instrument atmospheric air is directly ionized in a discharge ion source and the resulting water vapor clusters H3O+(H2O)n (n = 0..3) are detected with a linear quadrupole mass spectrometer as a direct measure of the atmospheric water vapor mixing ratio. AIMS is calibrated in-flight with a H2O calibration source using the catalytic reaction of H2 and O2 on a heated platinum surface to form gaseous H2O. This calibration setup combined with the water vapor mass spectrometry offers a powerful technical development in atmospheric hygrometry, enriching existing H2O measurement techniques by a new independent method. Here, we present AIMS water vapor measurements performed during the CONCERT2011 campaign (Contrail and Cirrus Experiment) with the DLR research aircraft Falcon. In September 2011 a deep stratospheric intrusion was probed over northern Europe with a dynamical tropopause lowered down to 6 km. We found sharp humidity gradients between tropospheric and stratospheric air at the edge of the tropopause fold, which we crossed 4 times at altitudes between 6 and 11 km. In the center of the tropopause fold, we measured water vapor mixing ratios down to 4 ppmv. The observed water vapor distribution is compared to water vapor analysis fields of the ECMWF's Integrated Forecast System (IFS) to evaluate the representation water vapor in this specific meteorological situation.

Liquid Water Cloud Measurements Using the Raman Lidar Technique: Current Understanding and Future Research Needs

NASA Technical Reports Server (NTRS)

Tetsu, Sakai; Whiteman, David N.; Russo, Felicita; Turner, David D.; Veselovskii, Igor; Melfi, S. Harvey; Nagai, Tomohiro; Mano, Yuzo

2013-01-01

This paper describes recent work in the Raman lidar liquid water cloud measurement technique. The range-resolved spectral measurements at the National Aeronautics and Space Administration Goddard Space Flight Center indicate that the Raman backscattering spectra measured in and below low clouds agree well with theoretical spectra for vapor and liquid water. The calibration coefficients of the liquid water measurement for the Raman lidar at the Atmospheric Radiation Measurement Program Southern Great Plains site of the U.S. Department of Energy were determined by comparison with the liquid water path (LWP) obtained with Atmospheric Emitted Radiance Interferometer (AERI) and the liquid water content (LWC) obtained with the millimeter wavelength cloud radar and water vapor radiometer (MMCR-WVR) together. These comparisons were used to estimate the Raman liquid water cross-sectional value. The results indicate a bias consistent with an effective liquid water Raman cross-sectional value that is 28%-46% lower than published, which may be explained by the fact that the difference in the detectors' sensitivity has not been accounted for. The LWP of a thin altostratus cloud showed good qualitative agreement between lidar retrievals and AERI. However, the overall ensemble of comparisons of LWP showed considerable scatter, possibly because of the different fields of view of the instruments, the 350-m distance between the instruments, and the horizontal inhomogeneity of the clouds. The LWC profiles for a thick stratus cloud showed agreement between lidar retrievals andMMCR-WVR between the cloud base and 150m above that where the optical depth was less than 3. Areas requiring further research in this technique are discussed.

Simultaneous speciation of inorganic arsenic, selenium and tellurium in environmental water samples by dispersive liquid liquid microextraction combined with electrothermal vaporization inductively coupled plasma mass spectrometry.

PubMed

Liu, Ying; He, Man; Chen, Beibei; Hu, Bin

2015-09-01

A new method based on dispersive liquid liquid microextraction (DLLME) combined with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) was developed for the simultaneous speciation of inorganic arsenic (As), selenium (Se) and tellurium (Te) with sodium diethyldithiocarbamate (DDTC) as both chelating reagent and chemical modifier. As(III), Se(IV) and Te(IV) were transformed into DDTC-chelates at pH 7 and extracted into the fine droplets formed by injecting the binary solution of bromobenzene (extraction solvent) and methanol (dispersive solvent) into the sample solution. After phase separation by centrifugation, As(III), Se(IV) and Te(IV) preconcentrated in the organic phase were determined by ETV-ICP-MS. Total inorganic As, Se and Te were obtained by reducing As(V), Se(VI) and Te(VI) to As(III), Se(IV) and Te(IV) with L-cysteine, which were then subjected to the same DLLME-ETV-ICP-MS process. The concentration of As(V), Se(VI), Te(VI) were calculated by subtracting the concentration of As(III), Se(IV) and Te(IV) from the total inorganic As, Se and Te, respectively. The main factors affecting the microextraction efficiency and the vaporization behavior of target species were investigated in detail. Under the optimal conditions, the limits of detection were 2.5, 8.6 and 0.56 ng L(-1) for As(III), Se(IV) and Te(IV), respectively, with the relative standard deviations (n=7) of 8.5-9.7%. The developed method was applied to the speciation of inorganic As, Se and Te in Certified Reference Materials of GSBZ50004-88, GBW(E)080395 and GBW(E)080548 environmental waters, and the determined values are in good agreement with the certified values. The method was also successfully applied to the simultaneous speciation of inorganic As, Se and Te in different environmental water samples with the recoveries in the range of 86.3-107% for the spiked samples. Copyright © 2015 Elsevier B.V. All rights reserved.

40 CFR 63.173 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Equipment Leaks § 63.173 Standards: Agitators in gas/vapor service and in light liquid service. (a)(1) Each... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 63.173 Section 63.173 Protection of Environment ENVIRONMENTAL...

40 CFR 63.173 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Equipment Leaks § 63.173 Standards: Agitators in gas/vapor service and in light liquid service. (a)(1) Each... 40 Protection of Environment 10 2012-07-01 2012-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 63.173 Section 63.173 Protection of Environment ENVIRONMENTAL...

40 CFR 65.106 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards: Valves in gas/vapor service and in light liquid service. (a) Compliance schedule. (1) The owner... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 65.106 Section 65.106 Protection of Environment ENVIRONMENTAL PROTECTION...

40 CFR 63.173 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Equipment Leaks § 63.173 Standards: Agitators in gas/vapor service and in light liquid service. (a)(1) Each... 40 Protection of Environment 10 2014-07-01 2014-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 63.173 Section 63.173 Protection of Environment ENVIRONMENTAL...

40 CFR 63.173 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Equipment Leaks § 63.173 Standards: Agitators in gas/vapor service and in light liquid service. (a)(1) Each... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 63.173 Section 63.173 Protection of Environment ENVIRONMENTAL...

40 CFR 63.174 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Equipment Leaks § 63.174 Standards: Connectors in gas/vapor service and in light liquid service. (a) The... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 63.174 Section 63.174 Protection of Environment ENVIRONMENTAL...

40 CFR 65.106 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Standards: Valves in gas/vapor service and in light liquid service. (a) Compliance schedule. (1) The owner... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 65.106 Section 65.106 Protection of Environment ENVIRONMENTAL PROTECTION...

40 CFR 63.174 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Equipment Leaks § 63.174 Standards: Connectors in gas/vapor service and in light liquid service. (a) The... 40 Protection of Environment 10 2012-07-01 2012-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 63.174 Section 63.174 Protection of Environment ENVIRONMENTAL...

40 CFR 65.106 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards: Valves in gas/vapor service and in light liquid service. (a) Compliance schedule. (1) The owner... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 65.106 Section 65.106 Protection of Environment ENVIRONMENTAL PROTECTION...

40 CFR 65.106 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Standards: Valves in gas/vapor service and in light liquid service. (a) Compliance schedule. (1) The owner... 40 Protection of Environment 16 2013-07-01 2013-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 65.106 Section 65.106 Protection of Environment ENVIRONMENTAL PROTECTION...

40 CFR 63.174 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Equipment Leaks § 63.174 Standards: Connectors in gas/vapor service and in light liquid service. (a) The... 40 Protection of Environment 10 2014-07-01 2014-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 63.174 Section 63.174 Protection of Environment ENVIRONMENTAL...

40 CFR 63.174 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Equipment Leaks § 63.174 Standards: Connectors in gas/vapor service and in light liquid service. (a) The... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 63.174 Section 63.174 Protection of Environment ENVIRONMENTAL...

40 CFR 63.174 - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Equipment Leaks § 63.174 Standards: Connectors in gas/vapor service and in light liquid service. (a) The... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 63.174 Section 63.174 Protection of Environment ENVIRONMENTAL...

40 CFR 63.173 - Standards: Agitators in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Equipment Leaks § 63.173 Standards: Agitators in gas/vapor service and in light liquid service. (a)(1) Each... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 63.173 Section 63.173 Protection of Environment ENVIRONMENTAL...

40 CFR 65.106 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Standards: Valves in gas/vapor service and in light liquid service. (a) Compliance schedule. (1) The owner... 40 Protection of Environment 16 2012-07-01 2012-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 65.106 Section 65.106 Protection of Environment ENVIRONMENTAL PROTECTION...

40 CFR 60.482-11a - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-11a Standards: Connectors in gas/vapor service and in light liquid service. (a) The owner or operator... connectors in gas and vapor and light liquid service as specified in paragraphs (a) and (b)(3) of this... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Connectors in gas/vapor...

40 CFR 60.482-11a - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-11a Standards: Connectors in gas/vapor service and in light liquid service. (a) The owner or operator... connectors in gas and vapor and light liquid service as specified in paragraphs (a) and (b)(3) of this... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards: Connectors in gas/vapor...

40 CFR 60.482-11a - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-11a Standards: Connectors in gas/vapor service and in light liquid service. (a) The owner or operator... connectors in gas and vapor and light liquid service as specified in paragraphs (a) and (b)(3) of this... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards: Connectors in gas/vapor...

40 CFR 60.482-11a - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-11a Standards: Connectors in gas/vapor service and in light liquid service. (a) The owner or operator... connectors in gas and vapor and light liquid service as specified in paragraphs (a) and (b)(3) of this... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards: Connectors in gas/vapor...

40 CFR 60.482-11a - Standards: Connectors in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-11a Standards: Connectors in gas/vapor service and in light liquid service. (a) The owner or operator... connectors in gas and vapor and light liquid service as specified in paragraphs (a) and (b)(3) of this... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards: Connectors in gas/vapor...

Preliminary characterization of a water vaporizer for resistojet applications

NASA Technical Reports Server (NTRS)

Morren, W. Earl

1992-01-01

A series of tests was conducted to explore the characteristics of a water vaporizer intended for application to resistojet propulsion systems. The objectives of these tests were to (1) observe the effect of orientation with respect to gravity on vaporizer stability, (2) characterize vaporizer efficiency and outlet conditions over a range of flow rates, and (3) measure the thrust performance of a vaporizer/resistojet thruster assembly. A laboratory model of a forced-flow, once-through water vaporizer employing a porous heat exchange medium was built and characterized over a range of flow rates and power levels of interest for application to water resistojets. In a test during which the vaporizer was rotated about a horizontal axis normal to its own axis, the outlet temperature and mass flow rate through the vaporizer remained steady. Throttlability to 30 percent of the maximum flow rate tested was demonstrated. The measured thermal efficiency of the vaporizer was near 0.9 for all tests. The water vaporizer was integrated with an engineering model multipropellant resistojet. Performance of the vaporizer/thruster assembly was measured over a narrow range of operating conditions. The maximum specific impulse measured was 234 s at a mass flow rate and specific power level (vaporizer and thruster combined) of 154 x 10(exp-6)kg/s and 6.8 MJ/kg, respectively.

Validation on MERSI/FY-3A precipitable water vapor product

NASA Astrophysics Data System (ADS)

Gong, Shaoqi; Fiifi Hagan, Daniel; Lu, Jing; Wang, Guojie

2018-01-01

The precipitable water vapor is one of the most active gases in the atmosphere which strongly affects the climate. China's second-generation polar orbit meteorological satellite FY-3A equipped with a Medium Resolution Spectral Imager (MERSI) is able to detect atmospheric water vapor. In this paper, water vapor data from AERONET, radiosonde and MODIS were used to validate the accuracy of the MERSI water vapor product in the different seasons and climatic regions of East Asia. The results show that the values of MERSI water vapor product are relatively lower than that of the other instruments and its accuracy is generally lower. The mean bias (MB) was -0.8 to -12.7 mm, the root mean square error (RMSE) was 2.2-17.0 mm, and the mean absolute percentage error (MAPE) varied from 31.8% to 44.1%. On the spatial variation, the accuracy of MERSI water vapor product in a descending order was from North China, West China, Japan -Korea, East China, to South China, while the seasonal variation of accuracy was the best for winter, followed by spring, then in autumn and the lowest in summer. It was found that the errors of MERSI water vapor product was mainly due to the low accuracy of radiation calibration of the MERSI absorption channel, along with the inaccurate look-up table of apparent reflectance and water vapor within the water vapor retrieved algorithm. In addition, the surface reflectance, the mixed pixels of image cloud, the humidity and temperature of atmospheric vertical profile and the haze were also found to have affected the accuracy of MERSI water vapor product.

New Density Functional Approach for Solid-Liquid-Vapor Transitions in Pure Materials

NASA Astrophysics Data System (ADS)

Kocher, Gabriel; Provatas, Nikolas

2015-04-01

A new phase field crystal (PFC) type theory is presented, which accounts for the full spectrum of solid-liquid-vapor phase transitions within the framework of a single density order parameter. Its equilibrium properties show the most quantitative features to date in PFC modeling of pure substances, and full consistency with thermodynamics in pressure-volume-temperature space is demonstrated. A method to control either the volume or the pressure of the system is also introduced. Nonequilibrium simulations show that 2- and 3-phase growth of solid, vapor, and liquid can be achieved, while our formalism also allows for a full range of pressure-induced transformations. This model opens up a new window for the study of pressure driven interactions of condensed phases with vapor, an experimentally relevant paradigm previously missing from phase field crystal theories.

Water vapor: An extraordinary terahertz wave source under optical excitation

NASA Astrophysics Data System (ADS)

Johnson, Keith; Price-Gallagher, Matthew; Mamer, Orval; Lesimple, Alain; Fletcher, Clark; Chen, Yunqing; Lu, Xiaofei; Yamaguchi, Masashi; Zhang, X.-C.

2008-09-01

In modern terahertz (THz) sensing and imaging spectroscopy, water is considered a nemesis to be avoided due to strong absorption in the THz frequency range. Here we report the first experimental demonstration and theoretical implications of using femtosecond laser pulses to generate intense broadband THz emission from water vapor. When we focused an intense laser pulse in water vapor contained in a gas cell or injected from a gas jet nozzle, an extraordinarily strong THz field from optically excited water vapor is observed. Water vapor has more than 50% greater THz generation efficiency than dry nitrogen. It had previously been assumed that the nonlinear generation of THz waves in this manner primarily involves a free-electron plasma, but we show that the molecular structure plays an essential role in the process. In particular, we found that THz wave generation from H2O vapor is significantly stronger than that from D2O vapor. Vibronic activities of water cluster ions, occurring naturally in water vapor, may possibly contribute to the observed isotope effect along with rovibrational contributions from the predominant monomers.

Stratospheric water vapor in the NCAR CCM2

NASA Technical Reports Server (NTRS)

Mote, Philip W.; Holton, James R.

1992-01-01

Results are presented of the water vapor distribution in a 3D GCM with good vertical resolution, a state-of-the-art transport scheme, and a realistic water vapor source in the middle atmosphere. In addition to water vapor, the model transported methane and an idealized clock tracer, which provides transport times to and within the middle atmosphere. The water vapor and methane distributions are compared with Nimbus 7 SAMS and LIMS data and with in situ measurements. It is argued that the hygropause in the model is maintained not by 'freeze-drying' at the tops of tropical cumulonimbus, but by a balance between two sources and one sink. Since the southern winter dehydration is unrealistically intense, this balance most likely does not resemble the balance in the real atmosphere.

Chemical reaction between water vapor and stressed glass

NASA Technical Reports Server (NTRS)

Soga, N.; Okamoto, T.; Hanada, T.; Kunugi, M.

1979-01-01

The crack velocity in soda-lime silicate glass was determined at room temperature at water-vapor pressures of 10 to 0.04 torr using the double torsion technique. A precracked glass specimen (70 x 16 x 1.6 mm) was placed in a vacuum chamber containing a four-point bending test apparatus. The plotted experimental results show that the crack propagation curve in water agrees fairly well with that of Wiederhorn (1967). Attention is given to the effect of water vapor pressure on crack velocity at K(I) = 550,000 N/m to the 3/2 power, with (Wiederhorn's data) or without N2 present. The plotted results reveal that the present crack velocity is about two orders of magnitude higher than that of Wiederhorn at high water-vapor conditions, but the difference decreases as the water-vapor concentration diminishes or the crack velocity slows down.

An Assessment of Upper Tropospheric Water Vapor in the MERRA-2 Reanalysis: Comparisons with MLS and In Situ Water Vapor Measurements

NASA Astrophysics Data System (ADS)

Selkirk, H. B.; Molod, A.; Pawson, S.; Douglass, A. R.; Voemel, H.; Hurst, D. F.; Jiang, J. H.; Read, W. G.; Schwartz, M. J.; Manyin, M.

2015-12-01

The recently released MERRA-2 reanalysis represents a significant evolution of the GEOS-5 atmospheric general circulation model and data assimilation system since the original MERRA project, and it is expected that MERRA-2 will be widely used in climate change studies as has its predecessor. A number of studies have demonstrated critical sensitivities of the climate system to the water vapor content of the upper troposphere and lower stratosphere (UT/LS) and it is therefore important to assess how well the MERRA-2 reanalysis represents the mean structure and variability of water vapor in this part of the atmosphere. Recent comparisons with MLS water vapor indicate that the ECMWF and original MERRA reanalyses overestimate water vapor throughout the global upper troposphere by 50-80%. These overestimates are particularly acute at 147 hPa and 215 hPa and occur in all seasons. In this presentation, we analyze differences between the MLS v.4.2 water vapor data and the new MERRA-2 reanalysis to assess improvements in the treatment of water vapor in the GEOS-5 system since MERRA. We also include in our analysis a comparison of MERRA-2 profiles with water vapor and relative humidity profiles from frostpoint hygrometers at five sites with long-term records and a sixth with an intensive campaign of one month. Three of the long-term sites, Boulder, Colorado, Lindenburg, Germany and Lauder, New Zealand, lie in middle latitudes, and two sites, San José, Costa Rica and Hilo, Hawaii, are in the tropics and subtropics, respectively. The campaign-only database is from the NASA SEAC4RS mission at Ellington Field, Houston, TX in 2013.

Vapor-liquid phase equilibria of potassium chloride-water mixtures: Equation-of-state representation for KCl-H2O and NaCl-H2O

USGS Publications Warehouse

Hovey, J.K.; Pitzer, Kenneth S.; Tanger, J.C.; Bischoff, J.L.; Rosenbauer, R.J.

1990-01-01

Measurements of isothermal vapor-liquid compositions for KCl-H2O as a function of pressure are reported. An equation of state, which was originally proposed by Pitzer and was improved and used by Tanger and Pitzer to fit the vapor-liquid coexistence surface for NaCl-H2O, has been used for representation of the KCl-H2O system from 300 to 410??C. Improved parameters are also reported for NaCl-H2O from 300 to 500??C. ?? 1990 American Chemical Society.

Effect of Liquid Surface Turbulent Motion on the Vapor Condensation in a Mixing Tank

NASA Technical Reports Server (NTRS)

Lin, C. S.; Hasan, M. M.

1991-01-01

The effect of liquid surface motion on the vapor condensation in a tank mixed by an axial turbulent jet is numerically investigated. The average value (over the interface area) of the root-mean-squared (rms) turbulent velocity at the interface is shown to be linearly increasing with decreasing liquid height and increasing jet diameter for a given tank size. The average rms turbulent velocity is incorporated in Brown et al. (1990) condensation correlation to predict the condensation of vapor on a liquid surface. The results are in good agreement with available condensation data.

Water recovery by catalytic treatment of urine vapor

NASA Technical Reports Server (NTRS)

Budininkas, P.; Quattrone, P. D.; Leban, M. I.

1980-01-01

The objective of this investigation was to demonstrate the feasibility of water recovery on a man-rated scale by the catalytic processing of untreated urine vapor. For this purpose, two catalytic systems, one capable of processing an air stream containing low urine vapor concentrations and another to process streams with high urine vapor concentrations, were designed, constructed, and tested to establish the quality of the recovered water.

Retrieval of Atmospheric Water Vapor Profiles from the Special Sensor Microwave TEMPERATURE-2

NASA Astrophysics Data System (ADS)

Al-Khalaf, Abdulrahman Khal

1995-01-01

Radiometric measurements from the Special Sensor Microwave/Temperature-2 (SSM/T-2) instrument are used to retrieve atmospheric water vapor profiles over ocean, land, coast, and ice/snow backgrounds. These measurements are used to retrieve vertical distribution of integrated water vapor (IWV) and total integrated water vapor (TIWV) using a physical algorithm. The algorithm infers the presence of cloud at a given height from super-saturation of the retrieved humidity at that height then the algorithm estimate the cloud liquid water content. Retrievals of IWV over five different layers are validated against available ground truth such as global radiosondes and ECMWF analyses. Over ocean, the retrieved total integrated water vapor (TIWV) and IWV close to the surface compare quite well, with those from radiosonde observations and the European Center for Medium Range Weather Forecasts (ECMWF) analyses. However, comparisons to radiosonde results are better than (ECMWF) analyses. TIWV root mean square (RMS) difference was 5.95 mm and TWV RMS difference for the lowest layer (SFC-850 mb) was 2.8 mm for radiosonde comparisons. Water vapor retrieval over land is less accurate than over ocean due to the low contrast between the surface and the atmosphere near the surface; therefore, land retrievals are more reliable at layers above 700 mb. However, TIWV and IWV at all layers compare appropriately with ground truth. Over coastal areas the agreement between retrieved water vapor profiles and ground truth is quite good for both TIWV and IWV for the five layers. The natural variability and large variations in the surface emissivity over ice and snow fields leads toward poor results. Clouds degrade retrievals over land and coast, improve the retrievals a little over ocean, and improve dramatically over snow/ice. Examples of retrieved relative humidity profiles were shown to illustrate the algorithm performance for the actual profile retrieval. The overall features of the retrieved

Advanced Atmospheric Water Vapor DIAL Detection System

NASA Technical Reports Server (NTRS)

Refaat, Tamer F.; Elsayed-Ali, Hani E.; DeYoung, Russell J. (Technical Monitor)

2000-01-01

Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. This thesis describes a new advanced detection system, which incorporates major improvements regarding sensitivity and size. These improvements include a low noise advanced avalanche photodiode detector, a custom analog circuit, a 14-bit digitizer, a microcontroller for on board averaging and finally a fast computer interface. This thesis describes the design and validation of this new water vapor DIAL detection system which was integrated onto a small Printed Circuit Board (PCB) with minimal weight and power consumption. Comparing its measurements to an existing DIAL system for aerosol and water vapor profiling validated the detection system.

Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.

PubMed

Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

2012-04-12

Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids.

Self-diffusion Coefficient and Structure of Binary n-Alkane Mixtures at the Liquid-Vapor Interfaces.

PubMed

Chilukoti, Hari Krishna; Kikugawa, Gota; Ohara, Taku

2015-10-15

The self-diffusion coefficient and molecular-scale structure of several binary n-alkane liquid mixtures in the liquid-vapor interface regions have been examined using molecular dynamics simulations. It was observed that in hexane-tetracosane mixture hexane molecules are accumulated in the liquid-vapor interface region and the accumulation intensity decreases with increase in a molar fraction of hexane in the examined range. Molecular alignment and configuration in the interface region of the liquid mixture change with a molar fraction of hexane. The self-diffusion coefficient in the direction parallel to the interface of both tetracosane and hexane in their binary mixture increases in the interface region. It was found that the self-diffusion coefficient of both tetracosane and hexane in their binary mixture is considerably higher in the vapor side of the interface region as the molar fraction of hexane goes lower, which is mostly due to the increase in local free volume caused by the local structure of the liquid in the interface region.

Improved thermal lattice Boltzmann model for simulation of liquid-vapor phase change

NASA Astrophysics Data System (ADS)

Li, Qing; Zhou, P.; Yan, H. J.

2017-12-01

In this paper, an improved thermal lattice Boltzmann (LB) model is proposed for simulating liquid-vapor phase change, which is aimed at improving an existing thermal LB model for liquid-vapor phase change [S. Gong and P. Cheng, Int. J. Heat Mass Transfer 55, 4923 (2012), 10.1016/j.ijheatmasstransfer.2012.04.037]. First, we emphasize that the replacement of ∇ .(λ ∇ T ) /∇.(λ ∇ T ) ρ cV ρ cV with ∇ .(χ ∇ T ) is an inappropriate treatment for diffuse interface modeling of liquid-vapor phase change. Furthermore, the error terms ∂t 0(T v ) +∇ .(T vv ) , which exist in the macroscopic temperature equation recovered from the previous model, are eliminated in the present model through a way that is consistent with the philosophy of the LB method. Moreover, the discrete effect of the source term is also eliminated in the present model. Numerical simulations are performed for droplet evaporation and bubble nucleation to validate the capability of the model for simulating liquid-vapor phase change. It is shown that the numerical results of the improved model agree well with those of a finite-difference scheme. Meanwhile, it is found that the replacement of ∇ .(λ ∇ T ) /∇ .(λ ∇ T ) ρ cV ρ cV with ∇ .(χ ∇ T ) leads to significant numerical errors and the error terms in the recovered macroscopic temperature equation also result in considerable errors.

40 CFR 63.168 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 63.168 Standards: Valves in gas/vapor service and in light liquid service. (a) The provisions of this section apply to valves that are either in gas service or in light liquid service. (1) The provisions are... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service...

40 CFR 63.168 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... § 63.168 Standards: Valves in gas/vapor service and in light liquid service. (a) The provisions of this section apply to valves that are either in gas service or in light liquid service. (1) The provisions are... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Standards: Valves in gas/vapor service...

40 CFR 63.168 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... § 63.168 Standards: Valves in gas/vapor service and in light liquid service. (a) The provisions of this section apply to valves that are either in gas service or in light liquid service. (1) The provisions are... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Standards: Valves in gas/vapor service...

40 CFR 63.168 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... § 63.168 Standards: Valves in gas/vapor service and in light liquid service. (a) The provisions of this section apply to valves that are either in gas service or in light liquid service. (1) The provisions are... 40 Protection of Environment 10 2014-07-01 2014-07-01 false Standards: Valves in gas/vapor service...

40 CFR 63.168 - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... § 63.168 Standards: Valves in gas/vapor service and in light liquid service. (a) The provisions of this section apply to valves that are either in gas service or in light liquid service. (1) The provisions are... 40 Protection of Environment 10 2012-07-01 2012-07-01 false Standards: Valves in gas/vapor service...

Liquid-Vapor Interface Configurations Investigated in Low Gravity

NASA Technical Reports Server (NTRS)

Concus, Paul; Finn, Robert; Weislogel, Mark M.

1998-01-01

The Interface Configuration Experiment (ICE) is part of a multifaceted study that is exploring the often striking behavior of liquid-vapor interfaces in low-gravity environments. Although the experiment was posed largely as a test of current mathematical theory, applications of the results should be manifold. In space almost every fluid system is affected, if not dominated, by capillarity (the effects of surface tension). As a result, knowledge of fluid interface behavior, in particular an equilibrium interface shape from which any analysis must begin, is fundamental--from the control of liquid fuels and oxygen in storage tanks to the design and development of inspace thermal systems, such as heat pipes and capillary pumped loops. ICE has increased, and should continue to increase, such knowledge as it probes the specific peculiarities of current theory upon which our present understanding rests. Several versions of ICE have been conducted in the drop towers at the NASA Lewis Research Center, on the space shuttles during the first and second United States Microgravity Laboratory missions (USML-1 and USML-2), and most recently aboard the Russian Mir space station. These studies focused on interfacial problems concerning the existence, uniqueness, configuration, stability, and flow characteristics of liquid-vapor interfaces. Results to date have clearly demonstrated the value of the present theory and the extent to which it can predict the behavior of capillary systems.

Preparing highly ordered glasses of discotic liquid crystalline systems by vapor deposition

NASA Astrophysics Data System (ADS)

Gujral, Ankit; Gomez, Jaritza; Bishop, Camille E.; Toney, Michael F.; Ediger, M. D.

Anisotropic molecular packing, particularly in highly ordered liquid-crystalline arrangements, has the potential for optimizing performance in organic electronic and optoelectronic applications. Here we show that physical vapor deposition can be used to prepare highly organized out-of-equilibrium (glassy) solids of discotic liquid-crystalline (LC) systems. Using grazing incidence x-ray scattering, we compare 3 systems: a rectangular columnar LC, a hexagonal columnar LC and a non-liquid crystal former. The packing motifs accessible by vapor deposition are highly organized and vary from face-on to edge-on columnar arrangements depending upon substrate temperature. A subset of these structures cannot be accessed under equilibrium conditions. The structures formed at a given substrate temperature can be understood as the result of the system partially equilibrating toward the structure of the free surface of the equilibrium liquid crystal. Consistent with this view, the structures formed are independent of the substrate material.

Water-Assisted Vapor Deposition of PEDOT Thin Film.

PubMed

Goktas, Hilal; Wang, Xiaoxue; Ugur, Asli; Gleason, Karen K

2015-07-01

The synthesis and characterization of poly(3,4-ethylenedioxythiophene) (PEDOT) using water-assisted vapor phase polymerization (VPP) and oxidative chemical vapor deposition (oCVD) are reported. For the VPP PEDOT, the oxidant, FeCl3 , is sublimated onto the substrate from a heated crucible in the reactor chamber and subsequently exposed to 3,4-ethylenedioxythiophene (EDOT) monomer and water vapor in the same reactor. The oCVD PEDOT was produced by introducing the oxidant, EDOT monomer, and water vapor simultaneously to the reactor. The enhancement of doping and crystallinity is observed in the water-assisted oCVD thin films. The high doping level observed at UV-vis-NIR spectra for the oCVD PEDOT, suggests that water acts as a solubilizing agent for oxidant and its byproducts. Although the VPP produced PEDOT thin films are fully amorphous, their conductivities are comparable with that of the oCVD produced ones. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design and the parametric testing of the space station prototype integrated vapor compression distillation water recovery module

NASA Technical Reports Server (NTRS)

Reveley, W. F.; Nuccio, P. P.

1975-01-01

Potable water for the Space Station Prototype life support system is generated by the vapor compression technique of vacuum distillation. A description of a complete three-man modular vapor compression water renovation loop that was built and tested is presented; included are all of the pumps, tankage, chemical post-treatment, instrumentation, and controls necessary to make the loop representative of an automatic, self-monitoring, null gravity system. The design rationale is given and the evolved configuration is described. Presented next are the results of an extensive parametric test during which distilled water was generated from urine and urinal flush water with concentration of solids in the evaporating liquid increasing progressively to 60 percent. Water quality, quantity and production rate are shown together with measured energy consumption rate in terms of watt-hours per kilogram of distilled water produced.

Condensation of vapor bubble in subcooled pool

NASA Astrophysics Data System (ADS)

Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.

2017-02-01

We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

Methodology for Assessing a Boiling Liquid Expanding Vapor Explosion (BLEVE) Blast Potential

NASA Technical Reports Server (NTRS)

Keddy, Chris P.

2012-01-01

Composite Vessels are now used to store a variety of fluids or gases including cryogenic fluids under pressure. Sudden failure of these vessels under certain conditions can lead to a potentially catastrophic vapor expansion if thermal control is not maintained prior to failure. This can lead to a "Boiling Liquid Expanding Vapor Explosion" or BLEVE.

Raman water vapor lidar calibration

NASA Astrophysics Data System (ADS)

Landulfo, E.; Da Costa, R. F.; Torres, A. S.; Lopes, F. J. S.; Whiteman, D. N.; Venable, D. D.

2009-09-01

We show here new results of a Raman LIDAR calibration methodology effort putting emphasis in the assessment of the cross-section ratio between water vapor and nitrogen by the use of a calibrated NIST traceable tungsten lamp. Therein we give a step by step procedure of how to employ such equipment by means of a mapping/scanning procedure over the receiving optics of a water vapor Raman LIDAR. This methodology has been independently used at Howard University Raman LIDAR and at IPEN Raman LIDAR what strongly supports its reproducibility and points towards an independently calibration methodology to be carried on within an experiment routine.

Water vapor diffusion membrane development

NASA Technical Reports Server (NTRS)

Tan, M. K.

1977-01-01

An application of the water vapor diffusion technique is examined whereby the permeated water vapor is vented to space vacuum to alleviate on-board waste storage and provide supplemental cooling. The work reported herein deals primarily with the vapor diffusion-heat rejection (VD-HR) as it applies to the Space Shuttle. A stack configuration was selected, designed and fabricated. An asymmetric cellulose acetate membrane, used in reverse osmosis application was selected and a special spacer was designed to enhance mixing and promote mass transfer. A skid-mount unit was assembled from components used in the bench unit although no attempt was made to render it flight-suitable. The operating conditions of the VD-HR were examined and defined and a 60-day continuous test was carried out. The membranes performed very well throughout the test; no membrane rupture and no unusual flux decay was observed. In addition, a tentative design for a flight-suitable VD-HR unit was made.

Refraction of microwave signals by water vapor

NASA Technical Reports Server (NTRS)

Goldfinger, A. D.

1980-01-01

Tropospheric water vapor causes a refractive path length effect which is typically 5-10% of the 'dry' tropospheric effect and as large as several meters at elevation angles below 5 deg. The vertical water vapor profile is quite variable, and measurements of intensive atmospheric parameters such as temperature and humidity limited to the surface do not adequately predict the refractive effect. It is suggested that a water vapor refraction model that is a function of the amount of precipitable water alone can be successful at low elevation angles. From an extensive study of numerical ray tracings through radiosonde balloon data, such a model has been constructed. The model predicts the effect at all latitudes and elevation angles between 2 and 10 deg to an accuracy of better than 4% (11 cm at 3 deg elevation angle).

Performance Modeling of an Airborne Raman Water Vapor Lidar

NASA Technical Reports Server (NTRS)

Whiteman, D. N.; Schwemmer, G.; Berkoff, T.; Plotkin, H.; Ramos-Izquierdo, L.; Pappalardo, G.

2000-01-01

A sophisticated Raman lidar numerical model had been developed. The model has been used to simulate the performance of two ground-based Raman water vapor lidar systems. After tuning the model using these ground-based measurements, the model is used to simulate the water vapor measurement capability of an airborne Raman lidar under both day-and night-time conditions for a wide range of water vapor conditions. The results indicate that, under many circumstances, the daytime measurements possess comparable resolution to an existing airborne differential absorption water vapor lidar while the nighttime measurement have higher resolution. In addition, a Raman lidar is capable of measurements not possible using a differential absorption system.

40 CFR 63.1028 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Standards § 63.1028 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1028 Section 63.1028 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1028 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Standards § 63.1028 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1028 Section 63.1028 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1008 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... § 63.1008 Connectors in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Connectors in gas and vapor service and in light liquid service standards. 63.1008 Section 63.1008 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1025 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Standards § 63.1025 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Valves in gas and vapor service and in light liquid service standards. 63.1025 Section 63.1025 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1028 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards § 63.1028 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1028 Section 63.1028 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1008 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... § 63.1008 Connectors in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Connectors in gas and vapor service and in light liquid service standards. 63.1008 Section 63.1008 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1025 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards § 63.1025 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Valves in gas and vapor service and in light liquid service standards. 63.1025 Section 63.1025 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1009 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... § 63.1009 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1009 Section 63.1009 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1009 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... § 63.1009 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1009 Section 63.1009 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1025 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards § 63.1025 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Valves in gas and vapor service and in light liquid service standards. 63.1025 Section 63.1025 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1008 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 63.1008 Connectors in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Connectors in gas and vapor service and in light liquid service standards. 63.1008 Section 63.1008 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1028 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Standards § 63.1028 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1028 Section 63.1028 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1008 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... § 63.1008 Connectors in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Connectors in gas and vapor service and in light liquid service standards. 63.1008 Section 63.1008 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1009 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 63.1009 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1009 Section 63.1009 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1009 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... § 63.1009 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1009 Section 63.1009 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1028 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards § 63.1028 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1028 Section 63.1028 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1025 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Standards § 63.1025 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Valves in gas and vapor service and in light liquid service standards. 63.1025 Section 63.1025 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1009 - Agitators in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... § 63.1009 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1009 Section 63.1009 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1008 - Connectors in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... § 63.1008 Connectors in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Connectors in gas and vapor service and in light liquid service standards. 63.1008 Section 63.1008 Protection of Environment ENVIRONMENTAL...

40 CFR 63.1025 - Valves in gas and vapor service and in light liquid service standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Standards § 63.1025 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Valves in gas and vapor service and in light liquid service standards. 63.1025 Section 63.1025 Protection of Environment ENVIRONMENTAL...

Characterization of upper troposphere water vapor measurements during AFWEX using LASE.

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

Ferrare, R. A.; Browell, E. V.; Ismail, I.

2002-07-15

Water vapor profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the ARM/FIRE Water Vapor Experiment (AFWEX) are used to characterize upper troposphere (UT) water vapor measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. Initial comparisons showed the average Vaisala radiosonde measurements to be 5-15% drier than the average LASE, Raman lidar, and DC-8 in situ diode laser hygrometer measurements. They show that corrections to the Raman lidar and Vaisala measurements significantly reduce these differences. Precipitable water vapor (PWV) derived from the LASE water vapor profiles agrees within 3% on average with PWV derived frommore » the ARM ground-based microwave radiometer (MWR). The agreement among the LASE, Raman lidar, and MWR measurements demonstrates how the LASE measurements can be used to characterize both profile and column water vapor measurements and that ARM Raman lidar, when calibrated using the MWR PWV, can provide accurate UT water vapor measurements.« less

A FGGE water vapor wind data set

NASA Technical Reports Server (NTRS)

Stewart, Tod R.; Hayden, Christopher M.

1985-01-01

It has been recognized for some time that water vapor structure visible in infrared imagery offers a potential for obtaining motion vectors when several images are considered in sequence (Fischer et al., 1981). A study evaluating water vapor winds obtained from the VISSR atmospheric sounder (Stewart et al., 1985) has confirmed the viability of the approach. More recently, 20 data sets have been produced from METEOSAT water vapor imagery for the FGGE period of 10-25 November 1979. Where possible, two data sets were prepared for each day at 0000 and 1200 GMT and compared with rawinsondes over Europe, Africa, and aircraft observations over the oceans. Procedures for obtaining winds were, in general, similar to the earlier study. Motions were detected both by a single pixel tracking and a cross correlation method by using three images individually separated by one hour. A height assignment was determined by matching the measured brightness temperature to the temperature structure represented by the FGGE-IIIB analyses. Results show that the METEOSAT water vapor winds provide uniform horizontal coverage of mid-level flow over the globe with good accuracy.

The Effect of Clouds on Water Vapor Profiling from the Millimeter-Wave Radiometric Measurements

NASA Technical Reports Server (NTRS)

Wang, J. R.; Spinhirne, J. D.; Racette, P.; Chang, L. A.; Hart, W.

1997-01-01

Simultaneous measurements with the millimeter-wave imaging radiometer (MIR), cloud lidar system (CLS), and the MODIS airborne simulator (MAS) were made aboard the NASA ER-2 aircraft over the western Pacific Ocean on 17-18 January 1993. These measurements were used to study the effects of clouds on water vapor profile retrievals based on millimeter-wave radiometer measurements. The CLS backscatter measurements (at 0.532 and 1.064 am) provided information on the heights and a detailed structure of cloud layers; the types of clouds could be positively identified. All 12 MAS channels (0.6-13 Am) essentially respond to all types of clouds, while the six MIR channels (89-220 GHz) show little sensitivity to cirrus clouds. The radiances from the 12-/Am and 0.875-gm channels of the MAS and the 89-GHz channel of the MIR were used to gauge the performance of the retrieval of water vapor profiles from the MIR observations under cloudy conditions. It was found that, for cirrus and absorptive (liquid) clouds, better than 80% of the retrieval was convergent when one of the three criteria was satisfied; that is, the radiance at 0.875 Am is less than 100 W/cm.sr, or the brightness at 12 Am is greater than 260 K, or brightness at 89 GHz is less than 270 K (equivalent to cloud liquid water of less than 0.04 g/cm). The range of these radiances for convergent retrieval increases markedly when the condition for convergent retrieval was somewhat relaxed. The algorithm of water vapor profiling from the MIR measurements could not perform adequately over the areas of storm-related clouds that scatter radiation at millimeter wavelengths.

Detection of water vapor on Jupiter

NASA Technical Reports Server (NTRS)

Larson, H. P.; Fink, U.; Treffers, R.; Gautier, T. N., III

1975-01-01

High-altitude (12.4 km) spectroscopic observations of Jupiter at 5 microns from the NASA 91.5 cm airborne infrared telescope have revealed 14 absorptions assigned to the rotation-vibration spectrum of water vapor. Preliminary analysis indicates a mixing ratio about 1 millionth for the vapor phase of water. Estimates of temperature (greater than about 300 K) and pressure (less than 20 atm) suggest observation of water deep in Jupiter's hot spots responsible for its 5 micron flux. Model-atmosphere calculations based on radiative-transfer theory may change these initial estimates and provide a better physical picture of Jupiter's atmosphere below the visible cloud tops.

Algorithm Estimates Microwave Water-Vapor Delay

NASA Technical Reports Server (NTRS)

Robinson, Steven E.

1989-01-01

Accuracy equals or exceeds conventional linear algorithms. "Profile" algorithm improved algorithm using water-vapor-radiometer data to produce estimates of microwave delays caused by water vapor in troposphere. Does not require site-specific and weather-dependent empirical parameters other than standard meteorological data, latitude, and altitude for use in conjunction with published standard atmospheric data. Basic premise of profile algorithm, wet-path delay approximated closely by solution to simplified version of nonlinear delay problem and generated numerically from each radiometer observation and simultaneous meteorological data.

Liquid-vapor equilibrium and interfacial properties of square wells in two dimensions

NASA Astrophysics Data System (ADS)

Armas-Pérez, Julio C.; Quintana-H, Jacqueline; Chapela, Gustavo A.

2013-01-01

Liquid-vapor coexistence and interfacial properties of square wells in two dimensions are calculated. Orthobaric densities, vapor pressures, surface tensions, and interfacial thicknesses are reported. Results are presented for a series of potential widths λ* = 1.4, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5, where λ* is given in units of the hard core diameter σ. Critical and triple points are explored. No critical point was found for λ* < 1.4. Corresponding states principle analysis is performed for the whole series. For λ* = 1.4 and 1.5 evidence is presented that at an intermediate temperature between the critical and the triple point temperatures the liquid branch becomes an amorphous solid. This point is recognized in Armas-Pérez et al. [unpublished] as a hexatic phase transition. It is located at reduced temperatures T* = 0.47 and 0.35 for λ* = 1.4 and 1.5, respectively. Properties such as the surface tension, vapor pressure, and interfacial thickness do not present any discontinuity at these points. This amorphous solid branch does not follow the corresponding state principle, which is only applied to liquids and gases.

Impact of groundwater levels on evaporation and water-vapor fluxes in highly saline soils

NASA Astrophysics Data System (ADS)

Munoz, J. F.; Hernández, M. F.; Braud, I.; Gironas, J. A.; Suarez, F. I.

2012-12-01

In aquifers of arid and hyper-arid zones, such as those occurring in the Chilean Andes high plateau, it is important to determine both the quantity and location of water discharges at the temporal scales of interest to close the basin's water budget and thus, to manage the water resource properly. In zones where shallow aquifers are the main source of water, overexploitation of the water resource changes the dynamics of water, heat and solute transport in the vadose zone. As aquifers are exploited, fluctuations in depth to groundwater are exacerbated. These fluctuations modify both soil structure and evaporation from the ground, which is typically the most important discharge from the water budget and is very difficult to estimate. Therefore, a correct quantification of evaporation from these soils is essential to improve the accuracy of the water balance estimation. The objective of this study was to investigate the evaporation processes and water-vapor fluxes in a soil column filled with a saline soil from the Salar del Huasco basin, Chile. Water content, electrical conductivity and temperature at different depths in the soil profile were monitored to determine the liquid and vapor fluxes within the soil column. The results showed that evaporation is negligible when the groundwater table is deeper than 1 m. For shallower groundwater levels, evaporation increases in an exponential fashion reaching a value of 3 mm/day when the groundwater table is near the surface of the ground. These evaporation rates are on the same order of magnitude than the field measurements, but slightly lower due to the controlled conditions maintained in the laboratory. Isothermal fluid fluxes were predominant over the non-isothermal fluid and water vapor fluxes. The net flux for all the phreatic levels tested in the laboratory showed different behaviors, with ascending or descending flows as a consequence of changes in water content and temperature distribution within the soil. It was

Microcapsules fabricated from liquid marbles stabilized with latex particles.

PubMed

Ueno, Kazuyuki; Hamasaki, Sho; Wanless, Erica J; Nakamura, Yoshinobu; Fujii, Syuji

2014-03-25

Millimeter- and centimeter-sized "liquid marbles" were readily prepared by rolling water droplets on a powder bed of dried submicrometer-sized polystyrene latex particles carrying poly[2-(diethylamino)ethyl methacrylate] hairs (PDEA-PS). Scanning electron microscopy studies indicated that flocs of the PDEA-PS particles were adsorbed at the surface of these water droplets, leading to stable spherical liquid marbles. The liquid marbles were deformed as a result of water evaporation to adopt a deflated spherical geometry, and the rate of water evaporation decreased with increasing atmospheric relative humidity. Conversely, liquid marbles formed using saturated aqueous LiCl solution led to atmospheric water absorption by the liquid marbles and a consequent mass increase. The liquid marbles can be transformed into polymeric capsules containing water by exposure to solvent vapor: the PDEA-PS particles were plasticized with the solvent vapor to form a polymer film at the air-water interface of the liquid marbles. The polymeric capsules with aqueous volumes of 250 μL or less kept their oblate ellipsoid/near spherical shape even after complete water evaporation, which confirmed that a rigid polymeric capsule was successfully formed. Both the rate of water evaporation from the pure water liquid marbles and the rate of water adsorption into the aqueous LiCl liquid marbles were reduced with an increase of solvent vapor treatment time. This suggests that the number and size of pores within the polymer particles/flocs on the liquid marble surface decreased due to film formation during exposure to organic solvent vapor. In addition, organic-inorganic composite capsules and colloidal crystal capsules were fabricated from liquid marbles containing aqueous SiO2 dispersions.

Kinetic and Mechanistic Study of Vapor-Phase Free Radical Polymerization onto Liquid Surfaces

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

Gupta, Malancha

The primary objective of this proposal was to study vapor deposition of polymers onto liquid surfaces. Deposition onto liquid surfaces is a relatively new area of research because the past few decades have focused on deposition onto solid materials. We used initiated chemical vapor deposition to deposit polymers onto the liquid surfaces. The process is a one-step, solventless, free-radical polymerization process in which monomer and initiator molecules are flowed into a vacuum chamber. We found that the surface tension interaction between the polymer and the liquid determines whether a film or nanoparticles are formed. We also found that we couldmore » form gels by using soluble monomers. We found that we could tune the size of the nanoparticles by varying the viscosity of the liquid and the process parameters including pressure and time. These insights allow scalable synthesis of polymer materials for a variety of separation and catalysis applications.« less

Hydrogen bonded structure, polarity, molecular motion and frequency fluctuations at liquid-vapor interface of a water-methanol mixture: an ab initio molecular dynamics study.

PubMed

Choudhuri, Jyoti Roy; Chandra, Amalendu

2014-10-07

We have performed ab initio molecular dynamics simulations of a liquid-vapor interfacial system consisting of a mixture of water and methanol molecules. Detailed results are obtained for the structural and dynamical properties of the bulk and interfacial regions of the mixture. Among structural properties, we have looked at the inhomogeneous density profiles of water and methanol molecules, hydrogen bond distributions and also the orientational profiles of bulk and interfacial molecules. The methanol molecules are found to have a higher propensity to be at the interface than water molecules. It is found that the interfacial molecules show preference for specific orientations so as to form water-methanol hydrogen bonds at the interface with the hydrophobic methyl group pointing towards the vapor side. It is also found that for both types of molecules, the dipole moment decreases at the interface. It is also found that the local electric field of water influences the dipole moment of methanol molecules. Among the dynamical properties, we have calculated the diffusion, orientational relaxation, hydrogen bond dynamics, and vibrational frequency fluctuations in bulk and interfacial regions. It is found that the diffusion and orientation relaxation of the interfacial molecules are faster than those of the bulk. However, the hydrogen bond lifetimes are longer at the interface which can be correlated with the time scales found from the decay of frequency time correlations. The slower hydrogen bond dynamics for the interfacial molecules with respect to bulk can be attributed to diminished cooperative effects at the interface due to reduced density and number of hydrogen bonds.

Water-Vapor Sorption Processes in Nanoporous MgO-Al2O3 Ceramics: the PAL Spectroscopy Study

NASA Astrophysics Data System (ADS)

Klym, Halyna; Ingram, Adam; Shpotyuk, Oleh; Hadzaman, Ivan; Solntsev, Viacheslav

2016-03-01

The water-vapor sorption processes in nanoporous MgO-Al2O3 ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra with characteristic lifetimes near 2 and 60-70 ns can be, respectively, attributed to ortho-positronium (o-Ps) traps in nanopores with 0.3- and 1.5-1.8-nm radii. The first o-Ps decaying process includes "pick-off" annihilation in the "bubbles" of liquid water, while the second is based on o-Ps interaction with physisorbed water molecules at the walls of the pores. In addition, the water vapor modifies structural defects located at the grain boundaries in a vicinity of pores, this process being accompanied by void fragmentation during water adsorption and agglomeration during water desorption after drying.

Water-Vapor Sorption Processes in Nanoporous MgO-Al2O3 Ceramics: the PAL Spectroscopy Study.

PubMed

Klym, Halyna; Ingram, Adam; Shpotyuk, Oleh; Hadzaman, Ivan; Solntsev, Viacheslav

2016-12-01

The water-vapor sorption processes in nanoporous MgO-Al2O3 ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra with characteristic lifetimes near 2 and 60-70 ns can be, respectively, attributed to ortho-positronium (o-Ps) traps in nanopores with 0.3- and 1.5-1.8-nm radii. The first o-Ps decaying process includes "pick-off" annihilation in the "bubbles" of liquid water, while the second is based on o-Ps interaction with physisorbed water molecules at the walls of the pores. In addition, the water vapor modifies structural defects located at the grain boundaries in a vicinity of pores, this process being accompanied by void fragmentation during water adsorption and agglomeration during water desorption after drying.

Water vapor, water-ice clouds, and dust in the North Polar Region

NASA Technical Reports Server (NTRS)

Tamppari, Leslie K.; Smith, Michael D.; Bass, Deborah S.; Hale, Amy S.

2006-01-01

The behavior of water vapor, water-ice and dust in the Martian atmosphere is important for understanding the overall Martian climate system, which is characterized by three main cycles: water, including water-ice, dust, and CO2. Understanding these cycles will lend insight into the behavior of the atmospheric dynamics, the atmosphere's ability to transport dust, water-ice, and vapor to different parts of the planet, and how that ability changes as a function of dust and water-ice loading.

Compatibility testing of spacecraft materials and spacestorable liquid propellants. [liquid and vapor fluorine and FLOX

NASA Technical Reports Server (NTRS)

Denson, J. R.; Toy, A.

1974-01-01

Compatibility data for aluminum alloy 2219-T87 and titanium alloy Ti-6Al-4V were obtained while these alloys were exposed to both liquid and vapor fluorine and FLOX at -320 F + or -10 F. These data were obtained using a new low cost compatibility method which incorporates totally sealed containers and double dogbone test specimens and propellants in the simultaneous exposure to vapor and liquid phases. The compatibility investigation covered a storage period in excess of one year. Pitting was more severe in the 2219-T87 aluminum alloy than in the Ti-6Al-4V titanium alloy for both fluorine and FLOX exposure. The degree of chemical attack is more severe in the presence of FLOX than in fluorine and phase. The mechanical properties of the two alloys were not affected by storage in either of the two propellants.

Water-vapor pressure control in a volume

NASA Technical Reports Server (NTRS)

Scialdone, J. J.

1978-01-01

The variation with time of the partial pressure of water in a volume that has openings to the outside environment and includes vapor sources was evaluated as a function of the purging flow and its vapor content. Experimental tests to estimate the diffusion of ambient humidity through openings and to validate calculated results were included. The purging flows required to produce and maintain a certain humidity in shipping containers, storage rooms, and clean rooms can be estimated with the relationship developed here. These purging flows are necessary to prevent the contamination, degradation, and other effects of water vapor on the systems inside these volumes.

Suppression of ENSO in a coupled model without water vapor feedback

NASA Astrophysics Data System (ADS)

Hall, A.; Manabe, S.

We examine 800-year time series of internally generated variability in both a coupled ocean-atmosphere model where water vapor anomalies are not allowed to interact with longwave radiation and one where they are. The ENSO-like phenomenon in the experiment without water vapor feedback is drastically suppressed both in amplitude and geographic extent relative to the experiment with water vapor feedback. Surprisingly, the reduced amplitude of ENSO-related sea surface temperature anomalies in the model without water vapor feedback cannot be attributed to greater longwave damping of sea surface temperature. (Differences between the two experiments in radiative feedback due to clouds counterbalance almost perfectly the differences in radiative feedback due to water vapor.) Rather, the interaction between water vapor anomalies and longwave radiation affects the ENSO-like phenomenon through its influence on the vertical structure of radiative heating: Because of the changes in water vapor associated with it, a given warm equatorial Pacific sea surface temperature anomaly is associated with a radiative heating profile that is much more gravitationally unstable when water vapor feedback is present. The warm sea surface temperature anomaly therefore results in more convection in the experiment with water vapor feedback. The increased convection, in turn, is related to a larger westerly wind-stress anomaly, which creates a larger decrease in upwelling of cold water, thereby enhancing the magnitude of the original warm sea surface temperature anomaly. In this manner, the interaction between water vapor anomalies and longwave radiation magnifies the air-sea interactions at the heart of the ENSO phenomenon; without this interaction, the coupling between sea surface temperature and wind stress is effectively reduced, resulting in smaller amplitude ENSO episodes with a more limited geographical extent.

Wetting phenomenon in the liquid-vapor phase coexistence of a partially miscible Lennard-Jones binary mixture

NASA Astrophysics Data System (ADS)

Ramírez-Santiago, Guillermo; Díaz-Herrera, Enrique; Moreno Razo, José A.

2004-03-01

We have carried out extensive equilibrium MD simulations to study wetting phenomena in the liquid-vapor phase coexistence of a partially miscible binary LJ mixture. We find that in the temperature range 0.60 ≤ T^* < 0.80, the system separates forming a liquid A-liquid B interface in coexistence with the vapor phase. At higher temperatures, 0.80 ≤ T^* < 1.25 the liquid phases are wet by the vapor phase. By studying the behavior of the surface tension as a function of temperature we estimate the wetting transition temperature (WTT) to be T^*_w≃ 0.80. The adsorption of molecules at the liquid-liquid interface shows a discontinuity at about T^*≃ 0.79 suggesting that the wetting transition is a first order phase transition. These results are in agreement with some experiments carried out in fluid binary mixtures. In addition, we estimated the consolute temperature to be T^* _cons≃ 1.25. The calculated phase diagram of the mixture suggest the existence of a tricritical point.

Dynamic Leidenfrost temperature on micro-textured surfaces: Acoustic wave absorption into thin vapor layer

NASA Astrophysics Data System (ADS)

Jerng, Dong Wook; Kim, Dong Eok

2018-01-01

The dynamic Leidenfrost phenomenon is governed by three types of pressure potentials induced via vapor hydrodynamics, liquid dynamic pressure, and the water hammer effect resulting from the generation of acoustic waves at the liquid-vapor interface. The prediction of the Leidenfrost temperature for a dynamic droplet needs quantitative evaluation and definition for each of the pressure fields. In particular, the textures on a heated surface can significantly affect the vapor hydrodynamics and the water hammer pressure. We present a quantitative model for evaluating the water hammer pressure on micro-textured surfaces taking into account the absorption of acoustic waves into the thin vapor layer. The model demonstrates that the strength of the acoustic flow into the liquid droplet, which directly contributes to the water hammer pressure, depends on the magnitude of the acoustic resistance (impedance) in the droplet and the vapor region. In consequence, the micro-textures of the surface and the increased spacing between them reduce the water hammer coefficient ( kh ) defined as the ratio of the acoustic flow into the droplet to total generated flow. Aided by numerical calculations that solve the laminar Navier-Stokes equation for the vapor flow, we also predict the dynamic Leidenfrost temperature on a micro-textured surface with reliable accuracy consistent with the experimental data.

Isotopic equilibrium between precipitation and water vapor: evidence from continental rains in central Kenya

NASA Astrophysics Data System (ADS)

Soderberg, K.; Gerlein, C.; Kemeny, P. C.; Caylor, K. K.

2013-12-01

An accurate understanding of the relationships between the isotopic composition of liquid water and that of water vapor in the environment can help describe hydrologic processes across many scales. One such relationship is the isotopic equilibrium between falling raindrops and the surrounding vapor. The degree of equilibration is used to model the isotopic composition of precipitation in isotope-enable general circulation models and land-atmosphere exchange models. Although this equilibrium has been a topic of isotope hydrology research for more than four decades, few studies have included vapor measurements to validate modeling efforts. Recent advances in laser technology have allowed for in situ vapor measurements at high temporal resolution (e.g., >1 Hz). Here we present concomitant rain and vapor measurements for a series of 17 rain events during the 'Continental' rainy season (June through August) at Mpala Research Center in central Kenya. Rain samples (n=218) were collected at intervals of 2 to 35 minutes (median of 3 minutes) depending on the rain rate (0.4 to 10.5 mm/hr). The volume-weighted mean rain values for δ18O, δ2H and D-excess (δ2H - 8* δ18O) were 0.1 ‰, 10.7 ‰, and 10.1 ‰. These values are more enriched than the annual weighted means reported for the area (-2.2 ‰, -7.6 ‰, and 11.0 ‰, respectively). Vapor was measured continuously at ~2Hz (DLT-100, Los Gatos Research), with an inverted funnel intake 4m above the ground surface. The mean vapor isotopic composition during the rain events was -10.0 +/- 1.2 ‰ (1 σ) for δ18O and -73.9 +/- 7.0 ‰ for δ2H. The difference between the rain sample isotopic composition and that of liquid in isotopic equilibrium with the corresponding vapor at the ambient temperature was 0.8 +/- 2.2 ‰ for δ18O and 6.2 +/- 7.0 ‰ for δ2H. This disequilibrium was found to correlate with the natural log of rain rate (R2 of 0.26 for δ18O and 0.46 for δ2H), with lower rain rates having larger

Vapor-liquid coexistence of the Stockmayer fluid in nonuniform external fields.

PubMed

Samin, Sela; Tsori, Yoav; Holm, Christian

2013-05-01

We investigate the structure and phase behavior of the Stockmayer fluid in the presence of nonuniform electric fields using molecular simulation. We find that an initially homogeneous vapor phase undergoes a local phase separation in a nonuniform field due to the combined effect of the field gradient and the fluid vapor-liquid equilibrium. This results in a high-density fluid condensing in the strong field region. The system polarization exhibits a strong field dependence due to the fluid condensation.

Dissolution kinetics of volatile organic compound vapors in water: An integrated experimental and computational study

NASA Astrophysics Data System (ADS)

Mahmoodlu, Mojtaba G.; Pontedeiro, Elizabeth M.; Pérez Guerrero, Jesús S.; Raoof, Amir; Majid Hassanizadeh, S.; van Genuchten, Martinus Th.

2017-01-01

In this study we performed batch experiments to investigate the dissolution kinetics of trichloroethylene (TCE) and toluene vapors in water at room temperature and atmospheric pressure. The batch systems consisted of a water reservoir and a connected headspace, the latter containing a small glass cylinder filled with pure volatile organic compound (VOC). Results showed that air phase concentrations of both TCE and toluene increased relatively quickly to their maximum values and then became constant. We considered subsequent dissolution into both stirred and unstirred water reservoirs. Results of the stirred experiments showed a quick increase in the VOC concentrations with time up to their solubility limit in water. VOC vapor dissolution was found to be independent of pH. In contrast, salinity had a significant effect on the solubility of TCE and toluene vapors. VOC evaporation and vapor dissolution in the stirred water reservoirs followed first-order rate processes. Observed data could be described well using both simplified analytical solutions, which decoupled the VOC dynamics in the air and water phases, as well as using more complete coupled solutions. However, the estimated evaporation (ke) and dissolution (kd) rate constants differed by up to 70% between the coupled and uncoupled formulations. We also numerically investigated the effects of fluid withdrawal from the small water reservoir due to sampling. While decoupling the VOC air and water phase mass transfer processes produced unreliable estimates of kd, the effects of fluid withdrawal on the estimated rate constants were found to be less important. The unstirred experiments showed a much slower increase in the dissolved VOC concentrations versus time. Molecular diffusion of the VOCs within the aqueous phase became then the limiting factor for mass transfer from air to water. Fluid withdrawal during sampling likely caused some minor convection within the reservoir, which was simulated by increasing the

Upper-Tropospheric Winds Derived from Geostationary Satellite Water Vapor Observations

NASA Technical Reports Server (NTRS)

Velden, Christopher S.; Hayden, Christopher M.; Nieman, Steven J.; Menzel, W. Paul; Wanzong, Steven; Goerss, James S.

1997-01-01

The coverage and quality of remotely sensed upper-tropospheric moisture parameters have improved considerably with the deployment of a new generation of operational geostationary meteorological satellites: GOES-8/9 and GMS-5. The GOES-8/9 water vapor imaging capabilities have increased as a result of improved radiometric sensitivity and higher spatial resolution. The addition of a water vapor sensing channel on the latest GMS permits nearly global viewing of upper-tropospheric water vapor (when joined with GOES and Meteosat) and enhances the commonality of geostationary meteorological satellite observing capabilities. Upper-tropospheric motions derived from sequential water vapor imagery provided by these satellites can be objectively extracted by automated techniques. Wind fields can be deduced in both cloudy and cloud-free environments. In addition to the spatially coherent nature of these vector fields, the GOES-8/9 multispectral water vapor sensing capabilities allow for determination of wind fields over multiple tropospheric layers in cloud-free environments. This article provides an update on the latest efforts to extract water vapor motion displacements over meteorological scales ranging from subsynoptic to global. The potential applications of these data to impact operations, numerical assimilation and prediction, and research studies are discussed.

Water Vapor Monitoring at the Roque de LOS Muchachos Observatory

NASA Astrophysics Data System (ADS)

Rodriguez-Espinosa, J. M.; Kidger, M.; del Rosario, J. C.; Trancho, G.

1997-12-01

We present the first results from a long-term campaign of water vapor monitoring at the Roque de los Muchachos Observatory (Canary Islands, Spain). This observatory is situated on a volcanic peak, on the small island of La Palma. Although its altitude is relatively low (2400 meters), our initial site-testing, taken for site selection for the Spanish 10m telescope project, shows that a significant fraction of nights have water vapor column of 1mm, or lower, with values of 2mm and lower being relatively common, even in summer. The water vapor column can be stable at under 1mm for several nights, with only minimal variations. We contrast the results obtained using an infrared radiometer (on loan from Kitt Peak National Observatory), with those obtained using the 940nm water vapor line and comment briefly on plans for future automatic monitoring of water vapor at the observatory.

Vapor-liquid equilibrium thermodynamics of N2 + CH4 - Model and Titan applications

NASA Technical Reports Server (NTRS)

Thompson, W. R.; Zollweg, John A.; Gabis, David H.

1992-01-01

A thermodynamic model is presented for vapor-liquid equilibrium in the N2 + CH4 system, which is implicated in calculations of the Titan tropospheric clouds' vapor-liquid equilibrium thermodynamics. This model imposes constraints on the consistency of experimental equilibrium data, and embodies temperature effects by encompassing enthalpy data; it readily calculates the saturation criteria, condensate composition, and latent heat for a given pressure-temperature profile of the Titan atmosphere. The N2 content of condensate is about half of that computed from Raoult's law, and about 30 percent greater than that computed from Henry's law.

Tracing Water Vapor and Ice During Dust Growth

NASA Astrophysics Data System (ADS)

Krijt, Sebastiaan; Ciesla, Fred J.; Bergin, Edwin A.

2016-12-01

The processes that govern the evolution of dust and water (in the form of vapor or ice) in protoplanetary disks are intimately connected. We have developed a model that simulates dust coagulation, dust dynamics (settling, turbulent mixing), vapor diffusion, and condensation/sublimation of volatiles onto grains in a vertical column of a protoplanetary disk. We employ the model to study how dust growth and dynamics influence the vertical distribution of water vapor and water ice in the region just outside the radial snowline. Our main finding is that coagulation (boosted by the enhanced stickiness of icy grains) and the ensuing vertical settling of solids results in water vapor being depleted, but not totally removed, from the region above the snowline on a timescale commensurate with the vertical turbulent mixing timescale. Depending on the strength of the turbulence and the temperature, the depletion can reach factors of up to ˜50 in the disk atmosphere. In our isothermal column, this vapor depletion results in the vertical snowline moving closer to the midplane (by up to 2 gas scale heights) and the gas-phase {{C}}/{{O}} ratio above the vertical snowline increasing. Our findings illustrate the importance of dynamical effects and the need for understanding coevolutionary dynamics of gas and solids in planet-forming environments.

A three-dimensional phase field model for nanowire growth by the vapor-liquid-solid mechanism

NASA Astrophysics Data System (ADS)

Wang, Yanming; Ryu, Seunghwa; McIntyre, Paul C.; Cai, Wei

2014-07-01

We present a three-dimensional multi-phase field model for catalyzed nanowire (NW) growth by the vapor-liquid-solid (VLS) mechanism. The equation of motion contains both a Ginzburg-Landau term for deposition and a diffusion (Cahn-Hilliard) term for interface relaxation without deposition. Direct deposition from vapor to solid, which competes with NW crystal growth through the molten catalyst droplet, is suppressed by assigning a very small kinetic coefficient at the solid-vapor interface. The thermodynamic self-consistency of the model is demonstrated by its ability to reproduce the equilibrium contact angles at the VLS junction. The incorporation of orientation dependent gradient energy leads to faceting of the solid-liquid and solid-vapor interfaces. The model successfully captures the curved shape of the NW base and the Gibbs-Thomson effect on growth velocity.

Investigation of water vapor motion winds from geostationary satellites

NASA Technical Reports Server (NTRS)

Velden, Christopher

1993-01-01

Motions deduced in animated water vapor imagery from geostationary satellites can be used to infer wind fields in cloudless regimes. For the past several years, CIMSS has been exploring this potentially important source of global-scale wind information. Recently, METEOSAT-3 data has become routinely available to both the U.S. operational and research community. Compared with the current GOES satellite, the METEOSAT has a superior resolution (5 km vs. 16 km) in its water vapor channel. Preliminary work: at CIMSS has demonstrated that wind sets derived from METEOSAT water vapor imagery can provide important upper-tropospheric wind information in data void areas, and can positively impact numerical model guidance in meteorological applications. Specifically, hurricane track forecasts can be improved. Currently, we are exploring methods to further improve the derivation and quality of the water vapor wind sets.

Characterization of Upper Troposphere Water Vapor Measurements during AFWEX using LASE

NASA Technical Reports Server (NTRS)

Ferrare, R. A.; Browell, E. V.; Ismail, S.; Kooi, S.; Brasseur, L. H.; Brackett, V. G.; Clayton, M.; Barrick, J.; Linne, H.; Lammert, A.

2002-01-01

Water vapor profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the ARM/FIRE Water Vapor Experiment (AFWEX) are used to characterize upper troposphere water vapor (UTWV) measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. Initial comparisons showed the average Vaisala radiosonde measurements to be 5-15% drier than the average LASE, Raman lidar, and DC-8 in situ diode laser hygrometer measurements. We show that corrections to the Raman lidar and Vaisala measurements significantly reduce these differences. Precipitable water vapor (PWV) derived from the LASE water vapor profiles agrees within 3% on average with PWV derived from the ARM ground-based microwave radiometer (MWR). The agreement among the LASE, Raman lidar, and MWR measurements demonstrates how the LASE measurements can be used to characterize both profile and column water vapor measurements and that ARM Raman lidar, when calibrated using the MWR PWV, can provide accurate UTWV measurements.

Evaluation of Vapor Pressure and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives

NASA Technical Reports Server (NTRS)

Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.

2008-01-01

Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible vapor pressures under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the vapor pressure and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present vapor pressure measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.

Water-mediated ion–ion interactions are enhanced at the water vapor–liquid interface

PubMed Central

Venkateshwaran, Vasudevan; Vembanur, Srivathsan; Garde, Shekhar

2014-01-01

There is overwhelming evidence that ions are present near the vapor–liquid interface of aqueous salt solutions. Charged groups can also be driven to interfaces by attaching them to hydrophobic moieties. Despite their importance in many self-assembly phenomena, how ion–ion interactions are affected by interfaces is not understood. We use molecular simulations to show that the effective forces between small ions change character dramatically near the water vapor–liquid interface. Specifically, the water-mediated attraction between oppositely charged ions is enhanced relative to that in bulk water. Further, the repulsion between like-charged ions is weaker than that expected from a continuum dielectric description and can even become attractive as the ions are drawn to the vapor side. We show that thermodynamics of ion association are governed by a delicate balance of ion hydration, interfacial tension, and restriction of capillary fluctuations at the interface, leading to nonintuitive phenomena, such as water-mediated like charge attraction. “Sticky” electrostatic interactions may have important consequences on biomolecular structure, assembly, and aggregation at soft liquid interfaces. We demonstrate this by studying an interfacially active model peptide that changes its structure from α-helical to a hairpin-turn–like one in response to charging of its ends. PMID:24889634

Targeted Nanoparticle Thermometry: A Method to Measure Local Temperature at the Nanoscale Point Where Water Vapor Nucleation Occurs.

PubMed

Alaulamie, Arwa A; Baral, Susil; Johnson, Samuel C; Richardson, Hugh H

2017-01-01

An optical nanothermometer technique based on laser trapping, moving and targeted attaching an erbium oxide nanoparticle cluster is developed to measure the local temperature. The authors apply this new nanoscale temperature measuring technique (limited by the size of the nanoparticles) to measure the temperature of vapor nucleation in water. Vapor nucleation is observed after superheating water above the boiling point for degassed and nondegassed water. The average nucleation temperature for water without gas is 560 K but this temperature is lowered by 100 K when gas is introduced into the water. The authors are able to measure the temperature inside the bubble during bubble formation and find that the temperature inside the bubble spikes to over 1000 K because the heat source (optically-heated nanorods) is no longer connected to liquid water and heat dissipation is greatly reduced. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vapor Bubbles

NASA Astrophysics Data System (ADS)

Prosperetti, Andrea

2017-01-01

This article reviews the fundamental physics of vapor bubbles in liquids. Work on bubble growth and condensation for stationary and translating bubbles is summarized and the differences with bubbles containing a permanent gas stressed. In particular, it is shown that the natural frequency of a vapor bubble is proportional not to the inverse radius, as for a gas bubble, but to the inverse radius raised to the power 2/3. Permanent gas dissolved in the liquid diffuses into the bubble with strong effects on its dynamics. The effects of the diffusion of heat and mass on the propagation of pressure waves in a vaporous bubbly liquid are discussed. Other topics briefly touched on include thermocapillary flow, plasmonic nanobubbles, and vapor bubbles in an immiscible liquid.

Characterization of Upper-Troposphere Water Vapor Measurements during AFWEX Using LASE

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

Ferrare, Richard; Browell, E. V.; Ismail, S.

Water vapor profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the ARM/FIRE Water Vapor Experiment (AFWEX) are used to characterize upper troposphere water vapor (UTWV) measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors over the Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in northern Oklahoma. LASE was deployed from the NASA DC-8 aircraft and measured water vapor over the ARM SGP Central Facility (CF) site during seven flights between November 27 and December 10, 2000. Initially, the DOE ARM SGP Cloud and Radiation Testbed (CART) Raman lidar (CARL) UTWVmore » profiles were about 5-7% wetter than LASE in the upper troposphere, and the Vaisala RS80-H radiosonde profiles were about 10% drier than LASE between 8-12 km. Scaling the Vaisala water vapor profiles to match the precipitable water vapor (PWV) measured by the ARM SGP microwave radiometer (MWR) did not change these results significantly. By accounting for an overlap correction of the CARL water vapor profiles and by employing schemes designed to correct the Vaisala RS80-H calibration method and account for the time response of the Vaisala RS80H water vapor sensor, the average differences between the CARL and Vaisala radiosonde upper troposphere water vapor profiles are reduced to about 5%, which is within the ARM goal of mean differences of less than 10%. The LASE and DC-8 in situ Diode Laser Hygrometer (DLH) UTWV measurements generally agreed to within about 3 to 4%. The DC-8 in situ frost point cryogenic hygrometer and Snow White chilled mirror measurements were drier than the LASE, Raman lidars, and corrected Vaisala RS80H measurements by about 10-25% and 10-15%, respectively. Sippican (formerly VIZ manufacturing) carbon hygristor radiosondes exhibited large variabilities and poor agreement with the other measurements. PWV derived from the LASE profiles agreed to within about 3% on average

40 CFR 60.482-7a - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-7a Standards: Valves in gas/vapor service and in light liquid service. (a)(1) Each valve shall be... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 60.482-7a Section 60.482-7a Protection of Environment ENVIRONMENTAL...

40 CFR 60.482-7a - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-7a Standards: Valves in gas/vapor service and in light liquid service. (a)(1) Each valve shall be... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 60.482-7a Section 60.482-7a Protection of Environment ENVIRONMENTAL...

40 CFR 60.482-7a - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-7a Standards: Valves in gas/vapor service and in light liquid service. (a)(1) Each valve shall be... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 60.482-7a Section 60.482-7a Protection of Environment ENVIRONMENTAL...

40 CFR 60.482-7a - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-7a Standards: Valves in gas/vapor service and in light liquid service. (a)(1) Each valve shall be... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 60.482-7a Section 60.482-7a Protection of Environment ENVIRONMENTAL...

40 CFR 60.482-7a - Standards: Valves in gas/vapor service and in light liquid service.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-7a Standards: Valves in gas/vapor service and in light liquid service. (a)(1) Each valve shall be... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 60.482-7a Section 60.482-7a Protection of Environment ENVIRONMENTAL...

Detection of Thermal Water Vapor Emission from W Hydrae

NASA Technical Reports Server (NTRS)

Neufeld, David A.; Chen, Wesley; Melnick, Gary J.; DeGraauw, Thijs; Feuchtgruber, Helmut; Harwitt, Martin

1997-01-01

We have detected four far-infrared emission lines of water vapor toward the evolved star W Hydrae, using the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO). This is the first detection of thermal water vapor emission from a circumstellar outflow.

Water vapor diffusion membranes

NASA Technical Reports Server (NTRS)

Holland, F. F., Jr.; Smith, J. K.

1974-01-01

The program is reported, which was designed to define the membrane technology of the vapor diffusion water recovery process and to test this technology using commercially available or experimental membranes. One membrane was selected, on the basis of the defined technology, and was subjected to a 30-day demonstration trial.

Analysis of the global ISCCP TOVS water vapor climatology

NASA Technical Reports Server (NTRS)

Wittmeyer, Ian L.; Vonder Haar, Thomas H.

1994-01-01

A climatological examination of the global water vapor field based on a multiyear period of successfull satellite-based observations is presented. Results from the multiyear global ISCCP TIROS Operational Vertical Sounder (TOVS) water vapor dataset as operationally produced by NESDIS and ISCCP are shown. The methods employed for the retrieval of precipitable water content (PWC) utilize infrared measurements collected by the TOVS instrument package flown aboard the NOAA series of operational polar-orbiting satellites. Strengths of this dataset include the nearly global daily coverage, availability for a multiyear period, operational internal quality checks, and its description of important features in the mean state of the atmosphere. Weaknesses of this PWC dataset include that the infrared sensors are unable to collect data in cloudy regions, the retrievals are strongly biased toward a land-based radiosonde first-guess dataset, and the description of high spatial and temporal variability is inadequate. Primary consequences of these factors are seen in the underestimation of ITCZ water vapor maxima, and underestimation of midlatitude water vapor mean and standard deviation values where transient atmospheric phenomena contribute significantly toward time means. A comparison of TOVS analyses to SSM/I data over ocean for the month of July 1988 shows fair agreement in the magnitude and distribution of the monthly mean values, but the TOVS fields exhibit much less temporal and spatial variability on a daily basis in comparison to the SSM/I analyses. The emphasis of this paper is on the presentation and documentation of an early satellite-based water vapor climatology, and description of factors that prevent a more accurate representation of the global water vapor field.

Methods for calculation of engineering parameters for gas separation. [vapor pressure and solubility of gases in organic liquids

NASA Technical Reports Server (NTRS)

Lawson, D. D.

1979-01-01

A group additivity method is generated which allows estimation, from the structural formulas alone, of the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. Using these two parameters and appropriate thermodynamic relations, the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids are predicted. It is also possible to use the data to evaluate organic and some inorganic liquids for use in gas separation stages or liquids as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

Water vapor - The wet blanket of microwave interferometry

NASA Technical Reports Server (NTRS)

Resch, G. M.

1980-01-01

The various techniques that utilize microwave interferometry could be employed to determine distances of several thousand kilometers with an accuracy of 1 cm or 2 cm. Such measurements would be useful to obtain new knowledge of earth dynamics, greater insight into fundamental astronomical constants, and the ability to accurately navigate a spacecraft in interplanetary flight. There is, however, a basic problem, related to the presence of tropospheric water vapor, which has to be overcome before such measurements can be realized. Differing amounts of water vapor over the interferometer stations cause errors in the differential time of arrival which is the principal observable quantity. Approaches for overcoming this problem are considered, taking into account requirements for water vapor calibration to support interferometric techniques.

Study on water vapor characteristic of typical heavy snowstorm case in Northern Xinjiang

NASA Astrophysics Data System (ADS)

Cui, C.; Zhang, J.

2017-12-01

Using the daily precipitation at 51 weather stations in the Northern Xinjiang from November to March during 2000—2012 and daily water vapor of NCEP/NCAR 6 h 1°×1° reanalysis data, the water vapor characteristics of 11 typical heavy snowstorm cases were studied. The result shows that the 11 cases are classified into 3 types: West of Northern Xinjiang and along Tianshan edge, north and east of Northern Xinjiang, west of Northern Xinjiang and west Tianshan. There are two main water vapor sources: Near the Mediterranean Sea, the Red Sea or near the Persian Gulf. There are two water vapor transport routes which are west, southwest and northwest, respectively. Water vapor from southwest route is more, that from northwest route is less. The top of water vapor is close to 300 hPa. The strongest water vapor transport level is between 650-750 hPa. Before the every occurrence of 11 heavy snowstorm processes, there are water vapor convergence between 600-1000 hPa in Northern Xinjiang.There are positive correlations between the snowstorm intensity and water vapor convergence between 600-1000 hPa, as well as the convergence strength, rang and duration time in Northern Xinjiang. Hence, some lowest values of the strongest water vapor transport, water vapor convergence and the upper and lower level jet streams are resented also and gave useful references for accurate heavy snowstorm forecasting.

Importance Profiles for Water Vapor

NASA Astrophysics Data System (ADS)

Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita

Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or ``kernel'' depends on whether specific humidity S, relative humidity R, or ln(R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

Importance Profiles for Water Vapor

NASA Astrophysics Data System (ADS)

Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita

2017-11-01

Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln( R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

Stratospheric water vapor measurements at Thule, Greenland, by means of a new 22 GHz spectrometer

NASA Astrophysics Data System (ADS)

Mevi, Gabriele; Muscari, Giovanni; Mari, Massimo; Meloni, Daniela; Di Iorio, Tatiana; Pace, Giandomenico; di Sarra, Alcide; Cacciani, Marco

2017-04-01

A new 22 GHz water vapor spectrometer, VESPA-22 (water Vapour Emission Spectrometer for Polar Atmosphere), was installed in July 2016 at the Thule High Arctic Atmospheric Observatory (THAAO) located at Thule Air Base (76.5° N, 68.8° W), Greenland, and participated in the intensive measurement campaign of the Study of the water VApour in the polar AtmosPhere (SVAAP) project. After the campaign VESPA-22 has continued to carry out measurements in an autonomous mode and has now obtained more than 6 months of data. VESPA-22 was designed and built at the Istituto Nazionale di Geofisica and Vulcanologia (INGV) and measures the 22.235 GHz water vapor emission line with a bandwidth of 500 MHz and a frequency resolution of 31 kHz. The collected spectra are inverted using an optimal estimation algorithm in order to retrieve water vapour vertical profiles from about 26 to 72 km with a vertical resolution varying from 4 to 7.5 km. The spectrometer can produce 2 to 4 vertical profiles a day, depending on season and weather conditions. VESPA-22 also measures the atmospheric optical depth at 22 GHz and can therefore provide an estimate of precipitable water vapor (PWV) with a temporal resolution of few minutes. The instrument is calibrated every 30 minutes using noise diodes and tipping curves, and requires a calibration with liquid nitrogen (LN2) only once every few months. We will present water vapor stratospheric profiles over Thule obtained during an almost complete yearly cycle. The retrieved profiles have been compared with the Aura/MLS H2O dataset. During autumn 2016 the two datasets show a mean difference of less than 5% and a correlation coefficient of about 0.9 at all altitudes between 26 to 60 km.

Atmospheric water vapor: Distribution and Empirical estimation in the atmosphere of Thailand

NASA Astrophysics Data System (ADS)

Phokate, S.

2017-09-01

Atmospheric water vapor is a crucial component of the Earth’s atmosphere, which is shown by precipitable water vapor. It is calculated from the upper air data. In Thailand, the data were collected from four measuring stations located in Chiang Mai, Ubon Ratchathani, Bangkok, and Songkhla during the years 1998-2013. The precipitable water vapor obtained from this investigation were used to define an empirical model associated with the vapor pressure, which is a surface data at the same stations. The result shows that the relationship has a relatively high level of reliability. The precipitable water vapor obtained from the upper air data is nearly equal to the value from the model. The model was used to calculate the precipitable water vapor from the surface data 85 stations across the country. The result shows that seasonal change of the precipitable water vapor was low in the dry season (November-April) and high in the rainy season (May-October). In addition, precipitable water vapor varies along the latitudes of the stations. The high value obtains for low latitudes, but it is low for high latitudes.

MIPAS middle atmosphere water vapor distributions

NASA Astrophysics Data System (ADS)

Garcia-Comas, Maya; Lopez-Puertas, Manuel; Funke, Bernd; Bermejo-Pantale, Diego; Stiller, Gabriele; Grabowski, Udo; von Clarmann, Thomas

Water vapor is a key constituent of the middle atmosphere. It is involved in the ozone chem-istry, it is the precursor of PSCs and PMCs, and it is an infrared cooler in the stratosphere. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard Envisat observes the H2O infrared emissions with high resolution up to the mesopause. We have derived water vapor abundance from MIPAS spectra using the IMK/IAA data processor, which includes the GRANADA non-LTE algorithm. That allows for accurate H2O retrievals in the atmospheric regions where its emissions are affected by non-LTE, i.e., above 50km and particularly in the polar summer. We describe the information gained from MIPAS spectra about the non-LTE processes affecting the H2O infrared emissions, discuss its uncertainties and present MIPAS pole-to-pole distributions of water vapor retrieved from the stratosphere to the upper meso-sphere. We pay special attention to its behavior in the polar summer mesosphere, where the presence of PMCs and particular dynamical events may perturb the H2O vertical distribution. We also compare our results with those from global circulation models and other independent measurements.

Density Relaxation of Liquid-Vapor Critical Fluids Examined in Earth's Gravity

NASA Technical Reports Server (NTRS)

Wilkinson, R. Allen

2000-01-01

This work shows quantitatively the pronounced differences between the density equilibration of very compressible dense fluids in Earth's gravity and those in microgravity. The work was performed onsite at the NASA Glenn Research Center at Lewis Field and is complete. Full details are given in references 1 and 2. Liquid-vapor critical fluids (e.g., water) at their critical temperature and pressure, are very compressible. They collapse under their own weight in Earth's gravity, allowing only a thin meniscus-like layer with the critical pressure to survive. This critical layer, however, greatly slows down the equilibration process of the entire sample. A complicating feature is the buoyancy-driven slow flows of layers of heavier and lighter fluid. This work highlights the incomplete understanding of the hydrodynamics involved in these fluids.

Shape Evolution of Metal Nanoparticles in Water Vapor Environment.

PubMed

Zhu, Beien; Xu, Zhen; Wang, Chunlei; Gao, Yi

2016-04-13

The structures of the metal nanoparticles are crucial for their catalytic activities. How to understand and even control the shape evolution of nanoparticles under reaction condition is a big challenge in heterogeneous catalysis. It has been proved that many reactive gases hold the capability of changing the structures and properties of metal nanoparticles. One interesting question is whether water vapor, such a ubiquitous environment, could induce the shape evolution of metal nanoparticles. So far this question has not received enough attention yet. In this work, we developed a model based on the density functional theory, the Wulff construction, and the Langmuir adsorption isotherm to explore the shape of metal nanoparticle at given temperature and water vapor pressure. By this model, we show clearly that water vapor could notably increase the fraction of (110) facets and decrease that of (111) facets for 3-8 nm Cu nanoparticles, which is perfectly consistent with the experimental observations. Further investigations indicate the water vapor has different effects on the different metal species (Cu, Au, Pt, and Pd). This work not only helps to understand the water vapor effect on the structures of metal nanoparticles but also proposes a simple but effective model to predict the shape of nanoparticles in certain environment.

The annual cycle of stratospheric water vapor in a general circulation model

NASA Technical Reports Server (NTRS)

Mote, Philip W.

1995-01-01

The application of general circulation models (GCM's) to stratospheric chemistry and transport both permits and requires a thorough investigation of stratospheric water vapor. The National Center for Atmospheric Research has redesigned its GCM, the Community Climate Model (CCM2), to enable studies of the chemistry and transport of tracers including water vapor; the importance of water vapor to the climate and chemistry of the stratosphere requires that it be better understood in the atmosphere and well represented in the model. In this study, methane is carried as a tracer and converted to water; this simple chemistry provides an adequate representation of the upper stratospheric water vapor source. The cold temperature bias in the winter polar stratosphere, which the CCM2 shares with other GCM's, produces excessive dehydration in the southern hemisphere, but this dry bias can be ameliorated by setting a minimum vapor pressure. The CCM2's water vapor distribution and seasonality compare favorably with observations in many respects, though seasonal variations including the upper stratospheric semiannual oscillation are generally too small. Southern polar dehydration affects midlatitude water vapor mixing ratios by a few tenths of a part per million, mostly after the demise of the vortex. The annual cycle of water vapor in the tropical and northern midlatitude lower stratosphere is dominated by drying at the tropical tropopause. Water vapor has a longer adjustment time than methane and had not reached equilibrium at the end of the 9 years simulated here.

Portable device for generation of ultra-pure water vapor feeds

NASA Astrophysics Data System (ADS)

Velin, P.; Stenman, U.; Skoglundh, M.; Carlsson, P.-A.

2017-11-01

A portable device for the generation of co-feeds of water vapor has been designed, constructed, and evaluated for flexible use as an add-on component to laboratory chemical reactors. The vapor is formed by catalytic oxidation of hydrogen, which benefits the formation of well-controlled minute concentrations of ultra-pure water. Analysis of the effluent stream by on-line mass spectrometry and Fourier transform infrared spectroscopy confirms that water vapor can be, with high precision, generated both rapidly and steadily over extended periods in the range of 100 ppm to 3 vol. % (limited by safety considerations) using a total flow of 100 to 1500 ml/min at normal temperature and pressure. Further, the device has been used complementary to a commercial water evaporator and mixing system to span water concentrations up to 12 vol. %. Finally, an operando diffuse reflective infrared Fourier transform spectroscopic measurement of palladium catalysed methane oxidation in the absence and presence of up to 1.0 vol. % water has been carried out to demonstrate the applicability of the device for co-feeding well-controlled low concentrations of water vapor to a common type of spectroscopic experiment. The possibilities of creating isotopically labeled water vapor as well as using tracer gases for dynamic experiments are discussed.

Portable device for generation of ultra-pure water vapor feeds.

PubMed

Velin, P; Stenman, U; Skoglundh, M; Carlsson, P-A

2017-11-01

A portable device for the generation of co-feeds of water vapor has been designed, constructed, and evaluated for flexible use as an add-on component to laboratory chemical reactors. The vapor is formed by catalytic oxidation of hydrogen, which benefits the formation of well-controlled minute concentrations of ultra-pure water. Analysis of the effluent stream by on-line mass spectrometry and Fourier transform infrared spectroscopy confirms that water vapor can be, with high precision, generated both rapidly and steadily over extended periods in the range of 100 ppm to 3 vol. % (limited by safety considerations) using a total flow of 100 to 1500 ml/min at normal temperature and pressure. Further, the device has been used complementary to a commercial water evaporator and mixing system to span water concentrations up to 12 vol. %. Finally, an operando diffuse reflective infrared Fourier transform spectroscopic measurement of palladium catalysed methane oxidation in the absence and presence of up to 1.0 vol. % water has been carried out to demonstrate the applicability of the device for co-feeding well-controlled low concentrations of water vapor to a common type of spectroscopic experiment. The possibilities of creating isotopically labeled water vapor as well as using tracer gases for dynamic experiments are discussed.

Cirrus and Water Vapor Transport in the Tropical Tropopause Layer

NASA Astrophysics Data System (ADS)

Dinh, Tra Phuong

Simulations of tropical-tropopause-layer (TTL) cirrus under the influence of a large-scale equatorial Kelvin wave have been performed in two dimensions. These simulations show that, even under the influence of the large-scale wave, radiatively induced dynamics in TTL cirrus plays an important role in the transport of water vapor in the vertical direction. In a typical TTL cirrus, the heating that results from absorption of radiation by ice crystals induces a mesoscale circulation. Advection of ice and water vapor by the radiatively induced circulation leads to the persistence of the cloud and upward advection of the cloudy air. Upward advection of the cloudy air is equivalent to upward transport of water vapor when the air above the cloud is drier than the cloudy air, and downward transport otherwise. In TTL cirrus, microphysical processes also contribute to transport of water vapor in the vertical direction. Ice nucleation and growth, followed by sedimentation and sublimation, always lead to downward transport of water vapor. The magnitude of the downward transport by microphysical processes increases with the relative humidity of the air surrounding the cloud. Moisture in the surrounding environment is important because there is continuous interactions between the cloudy and environmental air throughout the cloud boundary. In our simulations, when the air surrounding the cloud is subsaturated, hence drier than the cloudy air, the magnitude of the downward transport due to microphysical processes is smaller than that of the upward transport due to the radiatively induced advection of water vapor. The net result is upward transport of water vapor, and equivalently hydration of the lower stratosphere. On the other hand, when the surrounding air is supersaturated, hence moister than the cloudy air, microphysical and radiatively induced dynamical processes work in concert to induce downward transport of water vapor, that is dehydration of the lower stratosphere. TTL

Hurricane Isabel, Amount of Atmospheric Water Vapor Observed By AIRS

NASA Image and Video Library

2003-09-20

This false-color image shows the amount of atmospheric water vapor observed by AIRS two weeks prior to the passage of Hurricane Isabel, and then when it was a Category 5 storm. The region shown includes parts of South America and the West Indies. Puerto Rico is the large island below the upper left corner. Total water vapor represents the depth of a layer if all the water vapor in the atmosphere were to condense and fall to the surface. The color bar on the right sides of the plots give the thickness of this layer in millimeters (mm). The first image, from August 28, shows typical tropical water vapor amounts over the ocean: between roughly 25 and 50 mm, or 1 to 2 inches. The highest values of roughly 80 mm, seen as a red blob over South America, corresponds to intense thunderstorms. Thunderstorms pull in water vapor from surrounding regions and concentrate it, with much of it then falling as rain. http://photojournal.jpl.nasa.gov/catalog/PIA00430

CRISM Observations of Water Vapor and Carbon Monoxide

NASA Technical Reports Server (NTRS)

Smith, Michael D.; Wolff, Michael J.; Clancy, R. Todd

2008-01-01

Near-infrared spectra returned by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM, [1]) on-board the Mars Reconnaissance Orbiter (MRO) contain the clear spectral signature of several atmospheric gases including carbon dioxide (CO2), water vapor (H2O), and carbon monoxide (CO). Here we describe the seasonal and spatial mapping of water vapor and carbon dioxide for one full Martian year using CRISM spectra.

Is Water at the Graphite Interface Vapor-like or Ice-like?

PubMed

Qiu, Yuqing; Lupi, Laura; Molinero, Valeria

2018-04-05

Graphitic surfaces are the main component of soot, a major constituent of atmospheric aerosols. Experiments indicate that soots of different origins display a wide range of abilities to heterogeneously nucleate ice. The ability of pure graphite to nucleate ice in experiments, however, seems to be almost negligible. Nevertheless, molecular simulations with the monatomic water model mW with water-carbon interactions parameterized to reproduce the experimental contact angle of water on graphite predict that pure graphite nucleates ice. According to classical nucleation theory, the ability of a surface to nucleate ice is controlled by the binding free energy between ice immersed in liquid water and the surface. To establish whether the discrepancy in freezing efficiencies of graphite in mW simulations and experiments arises from the coarse resolution of the model or can be fixed by reparameterization, it is important to elucidate the contributions of the water-graphite, water-ice, and ice-water interfaces to the free energy, enthalpy, and entropy of binding for both water and the model. Here we use thermodynamic analysis and free energy calculations to determine these interfacial properties. We demonstrate that liquid water at the graphite interface is not ice-like or vapor-like: it has similar free energy, entropy, and enthalpy as water in the bulk. The thermodynamics of the water-graphite interface is well reproduced by the mW model. We find that the entropy of binding between graphite and ice is positive and dominated, in both experiments and simulations, by the favorable entropy of reducing the ice-water interface. Our analysis indicates that the discrepancy in freezing efficiencies of graphite in experiments and the simulations with mW arises from the inability of the model to simultaneously reproduce the contact angle of liquid water on graphite and the free energy of the ice-graphite interface. This transferability issue is intrinsic to the resolution of the

Development of an Airborne Micropulse Water Vapor DIAL

NASA Astrophysics Data System (ADS)

Nehrir, A. R.; Ismail, S.

2012-12-01

Water vapor plays a key role in many atmospheric processes affecting both weather and climate. Airborne measurements of tropospheric water vapor profiles have been a longstanding observational need to not only the active remote sensing community but also to the meteorological, weather forecasting, and climate/radiation science communities. Microscale measurements of tropospheric water vapor are important for enhancing near term meteorological forecasting capabilities while mesoscale and synopticscale measurements can lead to an enhanced understanding of the complex coupled feedback mechanisms between water vapor, temperature, aerosols, and clouds. To realize tropospheric measurements of water vapor profiles over the microscale-synopticscale areas of meteorological interest, a compact and cost effective airborne micropulse differential absorption lidar (DIAL) is being investigated using newly emerging semiconductor based laser technology. Ground based micropulse DIAL (MPD) measurements of tropospheric water vapor and aerosol profiles up to 6 km and 15 km, respectively, have been previously demonstrated using an all semiconductor based laser transmitter. The DIAL transmitter utilizes a master oscillator power amplifier (MOPA) configuration where two semiconductor seed lasers are used to seed a single pass traveling wave tapered semiconductor optical amplifier (TSOA), producing up to 7μJ pulse energies over a 1 μs pulse duration at a 10 kHz pulse repetition frequency (PRF). Intercomparisons between the ground based instrument measurements and radiosonde profiles demonstrating the MPD performance under varying atmospheric conditions will be presented. Work is currently ongoing to expand upon the ground based MPD concept and to develop a compact and cost effective system capable of deployment on a mid-low altitude aircraft such as the NASA Langley B200 King Air. Initial lab experiments show that a two-three fold increase in the laser energy compared to the ground

Integrated lab-in-syringe platform incorporating a membraneless gas-liquid separator for automatic cold vapor atomic absorption spectrometry.