Cadmium Vapor Concentration and Lifetime of the Upper Active Level of a He–Cd Nuclear-Pumped Laser at the 5s2 2D5/2–5p2P3/2 Cd II Transition

In this study, a simplified two-dimensional axisymmetric finite element analysis (FEA) model was developed, using COMSOL Multiphysics® software, to simulate the water vapor separation in a moisture-selective hollow-fiber membrane for the application of air dehumidification in wood drying processes. The membrane material was dense polydimethylsiloxane (PDMS). A single hollow fiber membrane was modelled. The mass and momentum transfer equations were simultaneously solved to compute the water vapor concentration profile in the single hollow fiber membrane. A water vapor removal experiment was conducted by using a lab-scale PDMS hollow fiber membrane module operated at constant temperature of 35 °C. Three operation parameters of air flow rate, vacuum pressure, and initial relative humidity (RH) were set at different levels. The final RH of dehydrated air was collected and converted to water vapor concentration to validate simulated results. The simulated results were fairly consistent with the experimental data. Both experimental and simulated results revealed that the water vapor removal efficiency of the membrane system was affected by air velocity and vacuum pressure. A high water vapor removal performance was achieved at a slow air velocity and high vacuum pressure. Subsequently, the correlation of Sherwood (Sh)–Reynolds (Re)–Schmidt (Sc) numbers of the PDMS membrane was established using the validated model, which is applicable at a constant temperature of 35 °C and vacuum pressure of 77.9 kPa. This study delivers an insight into the mass transport in the moisture-selective dense PDMS hollow fiber membrane-based air dehumidification process, with the aims of providing a useful reference to the scale-up design, process optimization and module development using hollow fiber membrane materials.

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PENETRATION OF RADIOACTIVE ISOPROPYL METHYLPHOSPHONOFLUORIDATE (SARIN) VAPOR THROUGH SKIN

Canadian Journal of Biochemistry and Physiology ◽

10.1139/o60-116 ◽

1960 ◽

Vol 38 (9) ◽

pp. 935-944 ◽

Cited By ~ 2

Author(s):

M. K. McPhail ◽

P. A. Adie

Keyword(s):

Exposure Time ◽

Vapor Concentration ◽

Constant Concentration ◽

Time Required

Studies have been made of the penetration of sarin (isopropyl methylphosphonofluoridate) tagged with P32 through the skin of rabbits. Sarin vapor at a constant concentration was passed through a plastic cup attached to the clipped bellies of rabbits. Using different sizes of cups it has been found that the L(ct)50 (concentration × exposure time required to kill 50% of the animals exposed) decreased as the exposure area was increased. From these experiments it was possible to determine how absorption through skin varies with area exposed, vapor concentration, and exposure time and to find the approximate 'ct' necessary to kill a rabbit for any area of skin exposed.

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Analysis of Vapor Evaporation Loss in Filling Gasoline into Tank

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.347-353.372 ◽

2011 ◽

Vol 347-353 ◽

pp. 372-375 ◽

Cited By ~ 1

Author(s):

Wei Qiu Huang ◽

Feng Li ◽

Shu Hua Zhao ◽

Jing Zhong

Keyword(s):

Mass Transfer ◽

Experimental System ◽

Pilot Scale ◽

Convective Transport ◽

Operating Conditions ◽

Vapor Concentration ◽

Air Mass ◽

Evaporation Loss ◽

Gas Space ◽

Gasoline Evaporation

A pilot-scale experimental system of filling gasoline into a tank was built to investigate gasoline vapor-air mass transfer in the tank gas space and the vapor evaporation loss from the tank in different operating conditions. The results showed that the higher the location of filling pipe exit inside the tank, the quicker the speed of the filling gasoline, and the higher the initial vapor concentration in the tank gas space, then the more severe the vapor-air convective transport and the larger the gasoline evaporation loss rates.

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Simultaneous measurements of fuel vapor concentration and temperature in a flash-boiling propane jet using laser-induced gratings

Journal of Raman Spectroscopy ◽

10.1002/jrs.4315 ◽

2013 ◽

Vol 44 (10) ◽

pp. 1356-1362 ◽

Cited By ~ 17

Author(s):

B. Roshani ◽

A. Flügel ◽

I. Schmitz ◽

D. N. Kozlov ◽

T. Seeger ◽

...

Keyword(s):

Vapor Concentration ◽

Fuel Vapor ◽

Simultaneous Measurements ◽

Flash Boiling

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On the Use of Monolayers to Reduce Evaporation From Stationary Water Pools

Journal of Heat Transfer ◽

10.1115/1.2910650 ◽

1993 ◽

Vol 115 (1) ◽

pp. 209-214 ◽

Cited By ~ 9

Author(s):

T. D. Tang ◽

M. T. Pauken ◽

S. M. Jeter ◽

S. I. Abdel-Khalik

Keyword(s):

Experimental Investigation ◽

Relative Humidity ◽

Water Surface ◽

Surface Film ◽

Free Water ◽

Vapor Concentration ◽

Controlled Environment ◽

Stearyl Alcohol ◽

Water Pool ◽

Evaporation Suppression

An experimental investigation has been conducted to quantify the extent by which monolayers of fatty alcohols can reduce evaporation from a deep stationary water pool within a controlled environment. Octadecanol (stearyl alcohol), C17H35–CH2–OH, was chosen as the surface film and ethanol was selected to be the spreading agent. Evaporation suppression of 60 percent was achieved at a water temperature of 25°C with an air temperature of 20°C and a relative humidity of 70 percent. The experimental techniques and data have been validated by comparing the measured evaporation rates for film-free water with earlier data published by other investigators. Data for the evaporation rates of water covered by octadecanol films were correlated as a function of vapor concentration differences between the water surface and air.

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Modeling of Gas Turbine Fuel Nozzle Spray

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.2815559 ◽

1997 ◽

Vol 119 (1) ◽

pp. 34-44 ◽

Cited By ~ 14

Author(s):

N. K. Rizk ◽

J. S. Chin ◽

M. K. Razdan

Keyword(s):

Gas Turbine ◽

Fuel Injection ◽

Near Field ◽

Continuous Phase ◽

Liquid Sheet ◽

Vapor Concentration ◽

Fuel Vapor ◽

Fuel Injector ◽

Gas Temperature ◽

Sheet Breakup

Satisfactory performance of the gas turbine combustor relies on the careful design of various components, particularly the fuel injector. It is, therefore, essential to establish a fundamental basis for fuel injection modeling that involves various atomization processes. A two-dimensional fuel injection model has been formulated to simulate the airflow within and downstream of the atomizer and address the formation and breakup of the liquid sheet formed at the atomizer exit. The sheet breakup under the effects of airblast, fuel pressure, or the combined atomization mode of the airassist type is considered in the calculation. The model accounts for secondary breakup of drops and the stochastic Lagrangian treatment of spray. The calculation of spray evaporation addresses both droplet heat-up and steady-state mechanisms, and fuel vapor concentration is based on the partial pressure concept. An enhanced evaporation model has been developed that accounts for multicomponent, finite mass diffusivity and conductivity effects, and addresses near-critical evaporation. The presents investigation involved predictions of flow and spray characteristics of two distinctively different fuel atomizers under both nonreacting and reacting conditions. The predictions of the continuous phase velocity components and the spray mean drop sizes agree well with the detailed measurements obtained for the two atomizers, which indicates the model accounts for key aspects of atomization. The model also provides insight into ligament formation and breakup at the atomizer exit and the initial drop sizes formed in the atomizer near field region where measurements are difficult to obtain. The calculations of the reacting spray show the fuel-rich region occupied most of the spray volume with two-peak radial gas temperature profiles. The results also provided local concentrations of unburned hydrocarbon (UHC) and carbon monoxide (CO) in atomizer flowfield, information that could support the effort to reduce emission levels of gas turbine combustors.

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Numerical Study of Bicomponent Droplet Vaporization in a High Pressure Environment

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/96-gt-442 ◽

1996 ◽

Cited By ~ 15

Author(s):

J. Stengele ◽

H.-J. Bauer ◽

S. Wittig

Keyword(s):

High Pressure ◽

High Temperature ◽

Gas Phase ◽

Numerical Study ◽

Droplet Evaporation ◽

Single Component ◽

Vapor Concentration ◽

Diffusion Limit ◽

Evaporation Process ◽

Droplet Vaporization

The understanding of multicomponent droplet evaporation in a high pressure and high temperature gas is of great importance for the design of modern gas turbine combustors, since the different volatilities of the droplet components affect strongly the vapor concentration and, therefore, the ignition and combustion process in the gas phase. Plenty of experimental and numerical research is already done to understand the droplet evaporation process. Until now, most numerical studies were carried out for single component droplets, but there is still lack of knowledge concerning evaporation of multicomponent droplets under supercritical pressures. In the study presented, the Diffusion Limit Model is applied to predict bicomponent droplet vaporization. The calculations are carried out for a stagnant droplet consisting of heptane and dodecane evaporating in a stagnant high pressure and high temperature nitrogen environment. Different temperature and pressure levels are analyzed in order to characterize their influence on the vaporization behavior. The model employed is fully transient in the liquid and the gas phase. It accounts for real gas effects, ambient gas solubility in the liquid phase, high pressure phase equilibrium and variable properties in the droplet and surrounding gas. It is found that for high gas temperatures (T = 2000 K) the evaporation time of the bicomponent droplet decreases with higher pressures, whereas for moderate gas temperatures (T = 800 K) the lifetime of the droplet first increases and then decreases when elevating the pressure. This is comparable to numerical results conducted with single component droplets. Generally, the droplet temperature increases with higher pressures reaching finally the critical mixture temperature of the fuel components. The numerical study shows also that the same tendencies of vapor concentration at the droplet surface and vapor mass flow are observed for different pressures. Additionally, there is almost no influence of the ambient pressure on fuel composition inside the droplet during the evaporation process.

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Degradation of Solid Oxide Fuel Cell Cathodes Accelerated at a High Water Vapor Concentration

Journal of Fuel Cell Science and Technology ◽

10.1115/1.3117608 ◽

2010 ◽

Vol 7 (2) ◽

Cited By ~ 20

Author(s):

S. H. Kim ◽

K. B. Shim ◽

C. S. Kim ◽

J. T. Chou ◽

T. Oshima ◽

...

Keyword(s):

Water Vapor ◽

Voltage Drop ◽

Cell Voltage ◽

High Water ◽

Solid Oxide ◽

Constant Current ◽

Vapor Concentration ◽

Water Vapor Concentration ◽

Oxide Fuel ◽

Constant Current Density

The influence of water vapor in air on power generation characteristic of solid oxide fuel cells was analyzed by measuring cell voltage at a constant current density, as a function of water vapor concentration at 800°C and 1000°C. Cell voltage change was negligible at 1000°C, while considerable voltage drop was observed at 800°C accelerated at high water vapor concentrations of 20 wt % and 40 wt %. It is considered that La2O3 formed on the (La0.8Sr0.2)0.98MnO3 surface, which is assumed to be the reason for a large voltage drop.

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