scholarly journals Effect of Ionizing Radiation on Moist Air Systems

1987 ◽  
Vol 112 ◽  
Author(s):  
Donald T. Reed ◽  
Richard A. Van Konynenburg
Keyword(s):  
Nitrous Oxide ◽  
Steady State ◽  
Water Vapor ◽  
Gas Phase ◽  
Radiation Chemistry ◽  
Water Systems ◽  
Gas Composition ◽  
Moist Air ◽  
Dry Air ◽  
Closed Systems

AbstractThe radiation chemistry of nitrogen/oxygen/water systems is reviewed. General radiolytic effects in dry nitrogen/oxygen systems are relatively well characterized. Irradiation results in the formation of steady state concentrations of ozone, nitrous oxide and nitrogen dioxide. In closed systems, the concentration observed depends on the total dose, temperature and initial gas composition. Only three studies have been published that focus on the radiation chemistry of nitrogen/oxygen/water homogeneous gas systems. Mixed phase work that is relevant to the gaseous system is also summarized. The presence of water vapor results in the formation of nitric acid and significantly changes the chemistry observed in dry air systems. Mechanistic evidence from the studies reviewed are summarized and discussed in relation to characterizing the gas phase during the containment period of a repository in tuff.

scholarly journals The lightness of water vapor helps to stabilize tropical climate

2020 ◽  
Vol 6 (19) ◽  
pp. eaba1951 ◽  
Author(s):  
Seth D. Seidel ◽  
Da Yang
Keyword(s):  
Water Vapor ◽  
Longwave Radiation ◽  
Tropical Climate ◽  
Climate Feedback ◽  
Tropical Atmosphere ◽  
Radiative Effect ◽  
Buoyancy Effect ◽  
Moist Air ◽  
Dry Air ◽  
Earth’S Climate

Moist air is lighter than dry air at the same temperature, pressure, and volume because the molecular weight of water is less than that of dry air. We call this the vapor buoyancy effect. Although this effect is well documented, its impact on Earth’s climate has been overlooked. Here, we show that the lightness of water vapor helps to stabilize tropical climate by increasing the outgoing longwave radiation (OLR). In the tropical atmosphere, buoyancy is horizontally uniform. Then, the vapor buoyancy in the moist regions must be balanced by warmer temperatures in the dry regions of the tropical atmosphere. These higher temperatures increase tropical OLR. This radiative effect increases with warming, leading to a negative climate feedback. At a near present-day surface temperature, vapor buoyancy is responsible for a radiative effect of 1 W/m2 and a negative climate feedback of about 0.15 W/m2 per kelvin.

scholarly journals <i>A Tale of Two Dust Storms</i>: analysis of a complex dust event in the Middle East

2019 ◽  
Vol 12 (9) ◽  
pp. 5101-5118 ◽  
Author(s):  
Steven D. Miller ◽  
Louie D. Grasso ◽  
Qijing Bian ◽  
Sonia M. Kreidenweis ◽  
Jack F. Dostalek ◽  
...  
Keyword(s):  
Water Vapor ◽  
Mineral Dust ◽  
Weather Prediction ◽  
Detection Threshold ◽  
Dust Storms ◽  
Moist Air ◽  
Air Mass ◽  
Dry Air ◽  
Environmental Controls ◽  
Dust Detection

Abstract. Lofted mineral dust over data-sparse regions presents considerable challenges to satellite-based remote sensing methods and numerical weather prediction alike. The southwest Asia domain is replete with such examples, with its diverse array of dust sources, dust mineralogy, and meteorologically driven lofting mechanisms on multiple spatial and temporal scales. A microcosm of these challenges occurred over 3–4 August 2016 when two dust plumes, one lofted within an inland dry air mass and another embedded within a moist air mass, met over the southern Arabian Peninsula. Whereas conventional infrared-based techniques readily detected the dry air mass dust plume, they experienced marked difficulties in detecting the moist air mass dust plume, becoming apparent when visible reflectance revealed the plume crossing over an adjacent dark water background. In combining information from numerical modeling, multi-satellite and multi-sensor observations of lofted dust and moisture profiles, and idealized radiative transfer simulations, we develop a better understanding of the environmental controls of this event, characterizing the sensitivity of infrared-based dust detection to column water vapor, dust vertical extent, and dust optical properties. Differences in assumptions of dust complex refractive index translate to variations in the sign and magnitude of the split-window brightness temperature difference commonly used for detecting mineral dust. A multi-sensor technique for mitigating the radiative masking effects of water vapor via modulation of the split-window dust-detection threshold, predicated on idealized simulations tied to these driving factors, is proposed and demonstrated. The new technique, indexed to an independent description of the surface-to-500 hPa atmospheric column moisture, reveals parts of the missing dust plume embedded in the moist air mass, with the best performance realized over land surfaces.

scholarly journals Virtualization

2007 ◽  
Vol 64 (4) ◽  
pp. 1405-1409 ◽  
Author(s):  
Peter R. Bannon
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Relative Density ◽  
Moist Air ◽  
Dry Air ◽  
Equivalent Mass ◽  
Solid Water ◽  
Virtual Temperature ◽  
Mass Volume

Abstract The virtual temperature of a moist air parcel is defined as the temperature of a dry air parcel having the same mass, volume, and pressure. It is shown here that a virtual air parcel can be formed diabatically by warming the parcel to its virtual temperature while replacing its water vapor with the equivalent mass of dry air under isobaric, isochoric conditions. Conversely a saturated virtual air parcel can be formed diabatically by cooling the parcel to its saturated virtual temperature while replacing some of its dry air with the equivalent mass of water vapor under isobaric, isochoric conditions. These processes of virtualization can be represented on a vapor pressure–temperature diagram. This diagram facilitates the comparison of the relative density of two moist air parcels at the same pressure. The effects of liquid and/or solid water can also be included.

The radiation chemistry of aqueous solutions of nitrous oxide

1965 ◽  
Vol 285 (1402) ◽  
pp. 339-359 ◽  
Keyword(s):  
Nitrous Oxide ◽  
Steady State ◽  
Aqueous Solutions ◽  
Dose Rate ◽  
Radiation Chemistry ◽  
Bimolecular Reaction ◽  
Unimolecular Decomposition ◽  
Solvated Electron ◽  
Concentrated Aqueous Solutions ◽  
Dose Effects

For carefully purified concentrated aqueous solutions of N 2 0, G (N 2 ) is initially greater than the steady state value of 3.0 and G (O 2 ) less than the steady state value of 1.45 when G (H 2 ) = G (H 2 O 2 ) = 0. For very dilute solutions G (N 2 ) is small, independent of dose rate and decreases with increasing dose and decreasing [N 2 O], while G (H 2 ) is initially > 0.45, independent of dose rate and decreases with dose. The high initial G (H 2 is not due to organic or other impurity and is thought to arise either from bimolecular reaction of e aq − . and H within a spur or track or from unimolecular decomposition of the solvated electron either to H 2 + O - or H + OH - or from a combination of both. The dose effects are attributed to competitive scavenging of e aq − . by H 2 O 2 as the latter is produced.

Converting Moist Air Into Water and Power

2008 ◽  
Author(s):  
Robert J. Vidmar
Keyword(s):  
Water Vapor ◽  
Heat Exchange ◽  
Latent Heat ◽  
Heat Exchangers ◽  
State Of The Art ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Ambient Water ◽  
Moist Air ◽  
Dry Air

A method to process moist air into dry air and water results in a surplus of energy for the process. The sun evaporates water everywhere on earth and expends 2.26 MJ/kg (429.9 Btu/lbm) for each kg (2.204 lbm) of water evaporated. A mass of 1 kg (2.204 lbm) of water with a mixing ratio of 0.3% in dry air represents 2.26 MJ (199 Btu) of latent heat energy distributed in a volume of approximately 333 cubic meters (11,759 cubic feet). A system is described by which ambient water vapor is enriched, condensed with the release of latent heat in a heat-exchange boiler, which vaporizes a working fluid used in a Rankine-cycle turbine generator system. Water vapor enrichment is achieved with a vapor-separation barrier. Fans draw moist air through an air-intake system which brings the air into contact with a large surface-area vapor-separation barrier. The intake of a compressor imposes a vacuum on the extraction side of the barrier at a pressure that is lower than the ambient water-vapor pressure. This pressure difference drives water vapor across the barrier into the compressor. A two-stage compressor is used to maintain the low pressure and convey water vapor at high temperature and near atmospheric pressure to a heat-exchange boiler. Two processes occur in the heat-exchange boiler: 1) water vapor condenses and is pumped out of the boiler, and 2) heat is transferred to a working fluid that vaporizes. The vaporized working fluid drives a turbine in a Rankine cycle with condenser. Exhaust heat from the turbine is dissipated with a water-cooled condenser. An air-cooled rock-bed system is suggested as an alternative, when water cooling is not possible. Current advances in materials, the efficiency of turbomachinery, and the effectiveness of heat exchangers suggest that a system can be conceived that is completely fueled by moist air and produces water and excess shaft horsepower that can be converted into electricity. The analysis treats turbomachinery and heat exchangers as ideal components constrained by the Carnot and isentropic efficiencies. Pumps and fans are treated as components with state-of-the-art efficiency. System computations for an ideal 100% efficient system indicate that approximately 25% of the latent heat can be converted to electricity. For a system made with contemporary state-of-the art components a yield of a few percent is predicted. Principles of operation and engineering details are quantified.

scholarly journals Effect of net gas volume changes on alveolar and arterial gas partial pressures in the presence of ventilation-perfusion mismatch

2019 ◽  
Vol 126 (3) ◽  
pp. 558-568 ◽  
Author(s):  
Ben Korman ◽  
Ranjan K. Dash ◽  
Philip J. Peyton
Keyword(s):  
Nitrous Oxide ◽  
Steady State ◽  
Partial Pressure ◽  
Gas Phase ◽  
Pressure Difference ◽  
Sulfur Hexafluoride ◽  
Volatile Anesthetic ◽  
State Equations ◽  
Arterial Partial Pressure ◽  
Gas Volume

The second gas effect (SGE) occurs when nitrous oxide enhances the uptake of volatile anesthetics administered simultaneously. Recent work shows that the SGE is greater in blood than in the gas phase, that this is due to ventilation-perfusion mismatch, that as mismatch increases, the SGE increases in blood but is diminished in the gas phase, and that these effects persist well into the period of nitrous oxide maintenance anesthesia. These modifications of the SGE are most pronounced with the low soluble agents in current use. We investigate further the effect of net gas volume loss during nitrous oxide uptake on low concentrations of other gases present using partial pressure-solubility diagrams. The steady-state equations of gas exchange were solved assuming a log-normal distribution of ventilation-perfusion ratios using Lebesgue-Stieltjes integration. It was shown that under these conditions the classical partial pressure-solubility diagram must be modified, that for currently used volatile anesthetic agents the alveolar-arterial partial pressure difference is less than that predicted in the past, and that the alveolar-arterial partial pressure difference may even be reversed during uptake in the case of highly insoluble gases such as sulfur hexafluoride. Comparing this with the situation described previously for nitrogen in steady-state air breathing, we show that for nitrogen, the direction of the alveolar-arterial gradient is opposite to the direction of net gas volume movement. Although gas uptake with ventilation-perfusion inequality exceeding that when matching is optimal is shown to be possible, it is less likely than alveolar-arterial partial pressure reversal. NEW & NOTEWORTHY Net uptake of gases administered with nitrous oxide may proceed against an alveolar-arterial partial pressure gradient. The alveolar-arterial gradient for nitrogen in the steady-state breathing air depends not only on the existence of a distribution of ventilation-perfusion ratios in the lung but also on the presence of a net change in gas volume and is opposite in direction to the direction of net gas volume uptake.

scholarly journals <i>A Tale of Two Dust Storms</i>: Analysis of a Complex Dust Event in the Middle East

2019 ◽  
Author(s):  
Steven D. Miller ◽  
Louie Grasso ◽  
Quijing Bian ◽  
Sonia Kreidenweis ◽  
Jack Dostalek ◽  
...  
Keyword(s):  
Water Vapor ◽  
Mineral Dust ◽  
Weather Prediction ◽  
Detection Threshold ◽  
Dust Storms ◽  
Moist Air ◽  
Air Mass ◽  
Dry Air ◽  
Environmental Controls ◽  
Dust Detection

Abstract. Lofted mineral dust over data-sparse regions presents considerable challenges to satellite-based remote sensing methods and numerical weather prediction alike. The Southwest Asia domain is replete with such examples, with its diverse array of dust sources, dust mineralogy, and meteorologically-driven lofting mechanisms on multiple spatial and temporal scales. A microcosm of these challenges occurred over 3–4 August 2016 when two dust plumes, one lofted within an inland dry air mass and another embedded within a moist air mass, met over the Southern Arabian Peninsula. Whereas conventional infrared-based techniques readily detected the dry air mass dust plume, they experienced marked difficulties in detecting the moist air mass dust plume, which only became apparent when visible reflectance revealed it crossing over an adjacent dark water background. In combining information from numerical modelling, multi-satellite/multi-sensor observations of lofted dust and moisture profiles, and idealized radiative transfer simulations, we develop a better understanding of the environmental controls of this event, characterizing the sensitivity of infrared-based dust detection to column water vapor, dust vertical extent, and dust optical properties. Differences in assumptions of dust complex refractive index translate to variations in the sign and magnitude of the split-window brightness temperature difference commonly used for detecting mineral dust. A multi-sensor technique for mitigating the radiative masking effects of water vapor via modulation of the split-window dust-detection threshold, predicated on idealized simulations tied to these driving factors, is proposed and demonstrated. The new technique, indexed to independent-sensor description of the surface-to-500 mb atmospheric column moisture, reveals parts of the missing dust plume embedded in the moist air mass, with best performance over land surfaces.

Interaction of H2O, O2 and H2 with Proton Conducting Oxides Based on Lanthanum Scandates

2019 ◽  
pp. 88-100
Author(s):  
A. S. Farlenkov ◽  
N. A. Zhuravlev ◽  
Т. A. Denisova ◽  
М. V. Ananyev
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Phase ◽  
Molecular Hydrogen ◽  
Proton Magnetic Resonance ◽  
Partial Pressure Of Oxygen ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Temperature Range ◽  
Apparent Level

The research uses the method of high-temperature thermogravimetric analysis to study the processes of interaction of the gas phase in the temperature range 300–950 °C in the partial pressure ranges of oxygen 8.1–50.7 kPa, water 6.1–24.3 kPa and hydrogen 4.1 kPa with La1–xSrxScO3–α oxides (x = 0; 0.04; 0.09). In the case of an increase in the partial pressure of water vapor at a constant partial pressure of oxygen (or hydrogen) in the gas phase, the apparent level of saturation of protons is shown to increase. An increase in the apparent level of saturation of protons of the sample also occurs with an increase in the partial pressure of oxygen at a constant partial pressure of water vapor in the gas phase. The paper discusses the causes of the observed processes. The research uses the hydrogen isotope exchange method with the equilibration of the isotope composition of the gas phase to study the incorporation of hydrogen into the structure of proton-conducting oxides based on strontium-doped lanthanum scandates. The concentrations of protons and deuterons were determined in the temperature range of 300–800 °C and a hydrogen pressure of 0.2 kPa for La0.91Sr0.09ScO3–α oxide. The paper discusses the role of oxygen vacancies in the process of incorporation of protons and deuterons from the atmosphere of molecular hydrogen into the structure of the proton conducting oxides La1–xSrxScO3–α (x = 0; 0.04; 0.09). The proton magnetic resonance method was used to study the local structure in the temperature range 23–110 °C at a rotation speed of 10 kHz (MAS) for La0.96Sr0.04ScO3–α oxide after thermogravimetric measurements in an atmosphere containing water vapor, and after exposures in molecular hydrogen atmosphere. The existence of proton defects incorporated into the volume of the investigated proton oxide from both the atmosphere containing water and the atmosphere containing molecular hydrogen is unambiguously shown. The paper considers the effect of the contributions of the volume and surface of La0.96Sr0.04ScO3–α oxide on the shape of the proton magnetic resonance spectra.

scholarly journals Post-Plasma Catalysis for Trichloroethylene Abatement with Ce-Doped Birnessite Downstream DC Corona Discharge Reactor

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 946
Author(s):  
Grêce Abdallah ◽  
Jean-Marc Giraudon ◽  
Rim Bitar ◽  
Nathalie De Geyter ◽  
Rino Morent ◽  
...  
Keyword(s):  
Corona Discharge ◽  
Active Oxygen Species ◽  
Surface Acidity ◽  
Good Stability ◽  
Ozone Decomposition ◽  
Moist Air ◽  
Plasma Catalysis ◽  
Dry Air ◽  
Water Tolerance ◽  
By Products

Trichloroethylene (TCE) removal was investigated in a post-plasma catalysis (PPC) configuration in nearly dry air (RH = 0.7%) and moist air (RH = 15%), using, for non-thermal plasma (NTP), a 10-pin-to-plate negative DC corona discharge and, for PPC, Ce0.01Mn as a catalyst, calcined at 400 °C (Ce0.01Mn-400) or treated with nitric acid (Ce0.01Mn-AT). One of the key points was to take advantage of the ozone emitted from NTP as a potential source of active oxygen species for further oxidation, at a very low temperature (100 °C), of untreated TCE and of potential gaseous hazardous by-products from the NTP. The plasma-assisted Ce0.01Mn-AT catalyst presented the best CO2 yield in dry air, with minimization of the formation of gaseous chlorinated by-products. This result was attributed to the high level of oxygen vacancies with a higher amount of Mn3+, improved specific surface area and strong surface acidity. These features also allow the promotion of ozone decomposition efficiency. Both catalysts exhibited good stability towards chlorine. Ce0.01Mn-AT tested in moist air (RH = 15%) showed good stability as a function of time, indicating good water tolerance also.

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