Transport properties of real moist air, dry air, steam, and water

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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A Study of Moist Air Condensation Characteristics in a Transonic Flow System

Energies ◽

10.3390/en14134052 ◽

2021 ◽

Vol 14 (13) ◽

pp. 4052

Author(s):

Jie Wang ◽

Hongfang Gu

Keyword(s):

Mach Number ◽

Relative Humidity ◽

Transonic Flow ◽

Flow System ◽

Plane Surface ◽

Droplet Growth ◽

Moist Air ◽

Dry Air ◽

Hydraulic Equipment ◽

Non Equilibrium

When water vapor in moist air reaches supersaturation in a transonic flow system, non-equilibrium condensation forms a large number of droplets which may adversely affect the operation of some thermal-hydraulic equipment. For a better understanding of this non-equilibrium condensing phenomenon, a numerical model is applied to analyze moist air condensation in a transonic flow system by using the theory of nucleation and droplet growth. The Benson model is adopted to correct the liquid-plane surface tension equation for realistic results. The results show that the distributions of pressure, temperature and Mach number in moist air are significantly different from those in dry air. The dry air model exaggerates the Mach number by 19% and reduces both the pressure and the temperature by 34% at the nozzle exit as compared with the moist air model. At a Laval nozzle, for example, the nucleation rate, droplet number and condensation rate increase significantly with increasing relative humidity. The results also reveal the fact that the number of condensate droplets increases rapidly when moist air reaches 60% relative humidity. These findings provide a fundamental approach to account for the effect of condensate droplet formation on moist gas in a transonic flow system.

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Mucosal injury and eicosanoid kinetics during hyperventilation-induced bronchoconstriction

Journal of Applied Physiology ◽

10.1152/jappl.1999.87.5.1724 ◽

1999 ◽

Vol 87 (5) ◽

pp. 1724-1733 ◽

Cited By ~ 14

Author(s):

Arthur N. Freed ◽

Yongqiang Wang ◽

Sharron McCulloch ◽

Teresa Myers ◽

Ryoichi Suzuki

Keyword(s):

Epithelial Cells ◽

Mucosal Injury ◽

Mucosal Damage ◽

Mediator Release ◽

Moist Air ◽

Dry Air ◽

Peripheral Airways ◽

Airway Constriction ◽

Peripheral Airway ◽

Balf Cell

Bronchoalveolar lavage (BAL) of canine peripheral airways was performed at various times after hyperventilation, and BAL fluid (BALF) cell and mediator data were used to evaluate two hypotheses: 1) hyperventilation-induced mucosal injury stimulates mediator production, and 2) mucosal damage is correlated with the magnitude of hyperventilation-induced bronchoconstriction. We found that epithelial cells increased in BALF immediately after a 2- and a 5-min dry air challenge (DAC). Prostaglandins D2 and F2α and thromboxane B2 were unchanged immediately after a 2-min DAC but were significantly increased after a 5-min DAC. Leukotriene C4, D4, and E4 did not increase until 5 min after DAC. Hyperventilation with warm moist air did not alter BALF cells or mediators and caused less airway obstruction that occurred earlier than DAC. BALF epithelial cells were correlated with mediator release, and mediator release and epithelial cells were correlated with hyperventilation-induced bronchoconstriction. These observations are consistent with the hypothesis that hyperventilation-induced mucosal damage initiates peripheral airway constriction via the release of biochemical mediators.

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The lightness of water vapor helps to stabilize tropical climate

Science Advances ◽

10.1126/sciadv.aba1951 ◽

2020 ◽

Vol 6 (19) ◽

pp. eaba1951 ◽

Cited By ~ 3

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.

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

Atmospheric Measurement Techniques ◽

10.5194/amt-12-5101-2019 ◽

2019 ◽

Vol 12 (9) ◽

pp. 5101-5118 ◽

Cited By ~ 2

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.

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Effects of Temperature and Humidity on the Metabolism of the Fasting Bed-Bug (Cimex lectularius), Hemiptera

Parasitology ◽

10.1017/s0031182000020813 ◽

1932 ◽

Vol 24 (3) ◽

pp. 419-428 ◽

Cited By ~ 30

Author(s):

Kenneth Mellanby

Keyword(s):

Dry Matter ◽

Moist Air ◽

Bed Bugs ◽

Bed Bug ◽

Dry Air ◽

Loss Of Weight ◽

Cent Relative Humidity ◽

Effects Of Temperature ◽

Rate Of Evaporation ◽

Food Reserves

A method is described by which individual bed-bugs, weighing only 5 mg., can be accurately weighed, and their rate of loss of weight measured during starvation.Fasting bed-bugs were kept for various periods at five temperatures, ranging from 8° C. to 37° C., and at four humidities—0, 30, 60 and 90 per cent. relative humidity—at each temperature. Analysis after the experiments showed that the same amounts of food reserves were used up at each humidity for one temperature, and, as more water was evaporated from those kept in dry air than from those in moist, the proportion of dry matter rose most rapidly in dry air. Protein was the main food reserve used.Although the rate of loss of water was greatest in dry air, the rate of loss was relatively greater in moist air when the saturation deficiencies are compared. It appears that the insects conserve their water in dry air, but their surface area being so great in comparison with their volume, they cannot prevent all evaporation. This evaporation is at a rate nearly proportional to the saturation deficiency of the air.In moist air water appears to be evaporated freely. It is suggested that the spiracles are kept closed more in dry air and less in moist, which accounts for the fact that the rate of evaporation is proportionately greatest in moist air.A comparison is made between the results obtained with Cimex and Rhodnius.

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III. Researches on vanadium.—Part III. Preliminary notice

Proceedings of the Royal Society of London ◽

10.1098/rspl.1869.0069 ◽

1870 ◽

Vol 18 (114-122) ◽

pp. 316-321

Keyword(s):

The State ◽

Percentage Increase ◽

Moist Air ◽

Dry Air

In the second part of “Researches on Vanadium,” it was stated that the metal absorbs hydrogen. This conclusion has been fully borne out by subsequent experiment; and it appears that the amount of absorbed or combined hydrogen taken up by the metal varies according to the state of division, first, of the chloride (VCl 2 ) from which the metal is prepared, and secondly, and especially, of the metal itself. The metal containing absorbed hydrogen slowly takes up oxygen on exposure to dry air, water being formed and the metal undergoing oxidation to the lowest oxide, V 2 O. At this point the oxidation stops, but in moist air it proceeds still further. The difficulty of obtaining metallic vanadium free from admixture of oxide has been again rendered evident. Perfectly pure tetrachloride was prepared in quantity, and from this pure dichloride was made. On heating this to whiteness in dry hydrogen for 48 hours a substance was obtained which gained on oxidation 70·7 per cent, (vanadium requiring 77·79 percentage increase), and therefore still contained a slight admixture of oxide.

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Studies on the Responses of the Female Aëdes Mosquito. Part I.—The Search for Attractant Vapours

Bulletin of Entomological Research ◽

10.1017/s0007485300025189 ◽

1951 ◽

Vol 42 (1) ◽

pp. 105-114 ◽

Cited By ~ 35

Author(s):

A. W. A. Brown ◽

D. S. Sarkaria ◽

R. P. Thompson

Keyword(s):

Chemical Compounds ◽

Aedes Mosquito ◽

Moist Air ◽

High Concentration ◽

Female Adult ◽

Billiard Ball ◽

Dry Air ◽

Air Stream ◽

Vapour Concentration ◽

Very High

The question of the attractancy of water-vapour, carbon dioxide and candidate attractant compounds was investigated by the use of an olfactometer emitting freely into a 360-cu. ft. cage filled with female adult Aëdes aegypti. Moist air (85 per cent. R.H.) was found to attract 3–5 times as many mosquitos as dry air (15 per cent. R.H.). A moistened billiard-ball was found to attract about seven times as many mosquitos as a dry one, the result being similar whether black or white balls were used. The attractancy was reduced and even reversed at very high room humidities.The addition of 10 per cent. CO2 to a dry air stream approximately doubled its ability to bring mosquitos within 0·5 inches of the olfactometer port. Its addition to a moist air-stream did not significantly increase its attractancy. Pure CO2 vapour proved to be no more attractive than dry air, and several times less attractive than moist air.A number of chemical compounds found in body exudations, and some housefly attractants, were tested in the olfactometer for their effect on Aëdes adults. None were consistently attractive, and many were significantly repellent. However, sweat itself proved significantly attractive at a low vapour concentration, while significantly repellent at a high concentration.

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II. On the relation of aqueous vapour to radiant heat

Proceedings of the Royal Society of London ◽

10.1098/rspl.1862.0072 ◽

1863 ◽

Vol 12 ◽

pp. 326-327

Keyword(s):

Rock Salt ◽

Radiant Heat ◽

Moist Air ◽

Humid Air ◽

Dry Air ◽

Experimental Tube

The object of this paper is to prove to meteorologists that they may apply, without misgiving, the results which the author has already announced, regarding the relation of aqueous vapour to radiant heat. The author describes new experiments made with dry and humid air, first, with an experimental tube stopped by plates of rock-salt; secondly, with an open experimental tube; and thirdly, with an arrangement in which both the plates and the tube were abandoned, dry air being caused to displace moist, and moist air dry, in the open aitmosphere.

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THERMAL TOLERANCE IN MACROCENTRUS ANCYLIVORUS ROH. (HYMENOPTERA: BRACONIDAE)

Canadian Journal of Zoology ◽

10.1139/z54-006 ◽

1954 ◽

Vol 32 (1) ◽

pp. 30-38 ◽

Cited By ~ 4

Author(s):

D. P. Pielou ◽

R. F. Glasser

Keyword(s):

High Temperatures ◽

Thermal Tolerance ◽

Direct Action ◽

Oriental Fruit Moth ◽

Moist Air ◽

Lethal Effects ◽

Old Adults ◽

Dry Air ◽

Sucrose Solutions ◽

Higher Temperature

The lethal effects of high temperatures were investigated on Macrocentrus ancy-livorus Roh., a parasite of the oriental fruit moth. Day-old adults were exposed to uniform high temperatures for fixed periods ranging from 15 min. to 8 hr. in different tests. Temperatures investigated ranged from 30° to 45 °C. The insects had been reared under uniform and rigidly specified conditions at constant temperatures. After exposure all the test insects were removed, put in bottles, and provided with 10% sucrose solutions as food. Mortality was recorded 24 hr. later. Sexes were kept separate. Tests at all temperatures and exposure times were carried out both in dry and in moist air. At temperatures up to 34 °C. mortality was light even at the 8-hr. exposure. At 44 °C. almost 100% mortality was recorded at the 1/2-hr. exposure. Between these limits mortality increased with higher temperature or lengthened exposure time; it was generally greater in dry air than in moist. Females were more resistant than males. Thermograph records from the peach growing areas of the Niagara peninsula showed that only in exceptionally hot summers could conditions cause appreciable death from the direct action of temperature alone.

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