The Rate of Evaporation of Water through Duplex Films

1948 ◽  
Vol 1 (2) ◽  
pp. 197 ◽  
Author(s):  
AR Gilby ◽  
E Heymann
Keyword(s):  
Atmospheric Pressure ◽  
Interfacial Layer ◽  
Water Surface ◽  
Complex Nature ◽  
Water Molecules ◽  
Total Evaporation ◽  
Film Evaporation ◽  
Wind Velocities ◽  
Rate Of Evaporation ◽  
The Stability

The stability of duplex films of hydrocarbon oils containing spreaders is discussed in this paper. Duplex films containing spreaders of high molecular weight and of complex nature, e.g. stand oil, eucalyptus residue, polymerized oleic acid, may remain spread for long periods but are thermodynamically metastable. The penetration of water molecules from a water surface through a duplex film has been discussed in terms of the evaporation resistances of the interfacial layer of spreader, the bulk layer of oil and the stagnant layer of air above the film. Evaporation through duplex films of thickness 1-100 μ has been studied in conditions of " still air " at atmospheric pressure and in a vacuum, and in non-turbulent winds at several controlled wind velocities. The efficiency of duplex films in reducing evaporation is greater in wind than in still air and Increases with the wind velocity. When duplex films thicker than 10 μ are placed on water surfaces, even a wind at 8 miles per hour does not increase the rate of evaporation. Thus with such films the resistance of the stagnant layer of air above the film is small compared with that of the oil layer and of the interfacial film of spreader. With all duplex films thicker than 10 μ the total evaporation resistance is proportional to the film thickness and depends on the nature of the spreader. An analysis of the experimental results suggests that the interfacial layer of spreader makes an appreciable contribution to the evaporation resistance of the duplex films under investigation. Approximate relative figures characterizing the magnitude of this contribution are calculated for several spreaders.

RATE OF EVAPORATION FROM A FREE-WATER SURFACE AS INFLUENCED BY EXPOSURE

1961 ◽  
Vol 41 (1) ◽  
pp. 199-203 ◽  
Author(s):  
A. C. Carder
Keyword(s):  
Water Surface ◽  
Meteorological Factors ◽  
Free Water ◽  
Water Evaporation ◽  
High Wind ◽  
Progressive Decrease ◽  
Factors Affecting ◽  
Wind Velocities ◽  
Rate Of Evaporation ◽  
Low Rate

In a 3-year free-water evaporation study, an evaporimeter tank in the open field lost 34.5 per cent more water than a tank sheltered by buildings and trees. Meteorological factors responsible for this difference appear to be high wind velocities and long daily periods of sunshine. Changes in temperature regime had no effect.Difference in evaporation from the two tanks led to examination of data obtained over 35 years from the sheltered tank. It was found that, although there was a progressive decrease in amount of evaporation over the years from this tank, rainfall at the same time had increased and that the effect of this increase on evaporation was roughly equal to that of all other factors affecting evaporation, such as a change in exposure, etc. Thus, the comparatively low rate of evaporation from the sheltered tank was undoubtedly due in part to the proximity of buildings and trees which had been established.

Effects of Aging on the Morphology of Rubber-Brass Interfacial Layer

2011 ◽  
Vol 39 (1) ◽  
pp. 20-43 ◽  
Author(s):  
A. Ashirgade ◽  
P. B. Harakuni ◽  
W. J. Vanooij
Keyword(s):  
Chemical Composition ◽  
Interfacial Layer ◽  
Secondary Ion Mass Spectrometry ◽  
Morphological Changes ◽  
Grazing Incidence ◽  
Complex Nature ◽  
Rubber Compound ◽  
Tire Cord ◽  
Morphological Transformation ◽  
Adhesion Promoter

Abstract Adhesion between rubber compound and brass-plated steel tire cord is crucial in governing the overall performance of tires. The rubber-brass interfacial adhesion is influenced by the chemical composition and thickness of the interfacial layer. It has been shown that the interfacial layer consists mainly of sulfides and oxides of copper and zinc. This paper discusses the effect of changes in the chemical composition and the structure of the interfacial layers due to addition of adhesion promoter resins. Grazing incidence x-ray diffraction (GIXRD) experiments were run on sulfidized polished brass coupons previously bonded to five experimental rubber compounds. It was confirmed that heat and humidity conditions lead to physical and chemical changes of the rubber-steel tire cord interfacial layer, closely related to the degree of rubber-brass adhesion. Morphological transformation of the interfacial layer led to loss of adhesion after aging. The adhesion promoter resins inhibit unfavorable morphological changes in the interfacial layer, thus stabilizing it during aging and prolonging failure. Tire cord adhesion tests illustrated that the one-component resins improved adhesion after aging using a rubber compound with lower cobalt loading. Based on the acquired diffraction profiles, these resins were also found to impede crystallization of the sulfide layer after aging, leading to improved adhesion. Secondary ion mass spectrometry depth profiles and scanning electron microscopy micrographs strongly corroborated the findings from GIXRD. This interfacial analysis adds valuable information to our understanding of the complex nature of the rubber-brass bonding mechanism.

scholarly journals The rate of evaporation of droplets. Evaporation and diffusion coefficients, and vapour pressures of dibutyl phthalate and butyl stearate

1946 ◽  
Vol 186 (1006) ◽  
pp. 368-390 ◽  
Keyword(s):  
Diffusion Coefficients ◽  
Atmospheric Pressure ◽  
Dibutyl Phthalate ◽  
Droplet Evaporation ◽  
Medium Size ◽  
Good Accordance ◽  
Butyl Stearate ◽  
Rate Of Evaporation ◽  
Low Pressures ◽  
And Diffusion

The rate of evaporation of drops of dibutyl phthalate and butyl stearate of radius approx. 0.5 mm. has been studied by means of a microbalance over a range of atmospheric pressures down to approx. 0*1 mm. of mercury. Wide departures from Langmuir’s evaporation formula were found to occur at these low pressures, but results are in good accordance with the theory of droplet evaporation advanced by Fuchs which hitherto has not been tested experimentally. This experimental verification of Fuch’s theory for droplets of medium size evaporating at low pressures shows that the theory can be applied to the evaporation of very small drops at atmospheric pressure. The vapour pressures of the above liquids have been measured by Knudsen’s method and the evaporation and diffusion coefficients calculated fro n the experimental data.

scholarly journals Synthesis and Complexation Properties of 2-Hydroxy-5-methoxyphenylphosphonic Acid (H3L1). Crystal Structure of the [Cu(H2L1)2(Н2О)2] Complex

2021 ◽  
Vol 91 (11) ◽  
pp. 2176-2186
Author(s):  
G. S. Tsebrikova ◽  
Yu. I. Rogacheva ◽  
I. S. Ivanova ◽  
A. B. Ilyukhin ◽  
V. P. Soloviev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Methoxy Group ◽  
Protonation Constants ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability ◽  
Intramolecular Hydrogen ◽  
Oxygen Atoms

Abstract 2-Hydroxy-5-methoxyphenylphosphonic acid (H3L1) and the complex [Cu(H2L1)2(H2O)2] were synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The polyhedron of the copper atom is an axially elongated square bipyramid with oxygen atoms of phenolic and of monodeprotonated phosphonic groups at the base and oxygen atoms of water molecules at the vertices. The protonation constants of the H3L1 acid and the stability constants of its Cu2+ complexes in water were determined by potentiometric titration. The protonation constants of the acid in water are significantly influenced by the intramolecular hydrogen bond and the methoxy group. The H3L1 acid forms complexes CuL‒ and CuL24‒ with Cu2+ in water.

Laboratory studies of wind–wave interactions

1968 ◽  
Vol 34 (1) ◽  
pp. 91-111 ◽  
Author(s):  
Jin Wu
Keyword(s):  
Surface Roughness ◽  
Wind Stress ◽  
Water Surface ◽  
Wind Wave ◽  
Wave Drag ◽  
Average Height ◽  
Drift Current ◽  
Stress Coefficient ◽  
Wide Range ◽  
Wind Velocities

The present study consists of wind profile surveys, drift current measurements and water surface observations for a wide range of wind velocities in a wind–wave tank. It is confirmed that the velocity distribution essentially follows the logarithmic law near the water surface and the velocity-defect law toward the outer edge of the boundary layer. The wind stresses and surface roughnesses calculated from these distributions are divided into two groups separated by the occurrence of the wave-breaking phenomenon. For low wind velocities the surface roughness is dictated by ripples, and the wind-stress coefficient varies with U0−½, where U0 is the free-stream wind velocity. The surface roughness is proportional to the average height of the basic gravity wave at higher wind velocities; the stress coefficient is then proportional to U0. In addition, it is found that Charnock's expression (k ∝ u*2/g) holds only at high wind velocities, and that the constant of proportionality determined from the present experiment correlates very well with field observations. A new technique, involving the use of various-sized surface floats to determine the drift current gradient and the surface drift current, has been developed. A good agreement is shown between the gradients obtained from the measured currents and those determined from the wind stresses. Finally, the wind-stress coefficient is shown to be larger than the friction coefficient for turbulent flow along a solid rough surface; the difference is shown to be the wave drag of the wind over the water surface.

scholarly journals Experimental Study on 2D Motion Characteristics of Submerged Floating Tunnel in Waves

2020 ◽  
Vol 8 (2) ◽  
pp. 123 ◽  
Author(s):  
Zhiwen Yang ◽  
Jinzhao Li ◽  
Huaqing Zhang ◽  
Chunguang Yuan ◽  
Hua Yang
Keyword(s):  
Wave Height ◽  
Water Surface ◽  
Weight Ratio ◽  
Mooring Line ◽  
Natural Period ◽  
Main Challenge ◽  
Line Angle ◽  
Submerged Floating Tunnel ◽  
Motion Characteristics ◽  
The Stability

Submerged floating tunnel (SFT) is a new type of transportation infrastructure for crossing sea straits in relatively deeper water. Compared with the fixed tunnel, the main challenge in designing a SFT is the stability maintaining in a complex hydrodynamic environment, especially for the wave-induced dynamic load. In this study, a series of systematic experiments were conducted to investigate the 2D motion characteristics (i.e., heave, sway and roll) of the SFT exposed to regular waves. The movement of the SFT model is measured by the image processing method which is a noncontact measurement. The experimental observation of SFT motion during the process of wave and SFT interaction is described in detail, and the influence of several governing parameters is thoroughly analyzed, including the wave height and period, submergence depth, buoyancy to weight ratio (BWR), and the mooring line angle. The results show that the motion amplitudes of SFT increase with the wave height increasing. The effect of wave period is related to the natural period of the structure. The sway, heave and roll of the SFT submerged beneath the water surface are much smaller than that of the SFT on the water surface. With the increase of BWR, the motion of SFT decreases. The motion amplitude increases with mooring line angle increasing. Finally, empirical equations are proposed to estimate the motion characteristics of the SFT.

Experimental and Modeling Study of the Stability of the Atmospheric Pressure Plasma Jet

2007 ◽  
Author(s):  
Alexandre V. Chirokov ◽  
Shailesh P. Gangoli ◽  
Alexander A. Fridman ◽  
Alexander. F. Gutsol ◽  
Alexander Dolgopolsky ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Atmospheric Pressure Plasma Jet ◽  
Pressure Plasma ◽  
The Stability ◽  
Modeling Study

Swarm Coordination Under Conflict and Use of Enhanced Lyapunov Based Controller

2009 ◽  
Author(s):  
Daniel A. Sierra ◽  
Paul McCullough ◽  
Nejat Olgac ◽  
Eldridge Adams
Keyword(s):  
Stability Analysis ◽  
Distributed Control ◽  
Complex Nature ◽  
Control Logic ◽  
Group Pursuit ◽  
Dissipative Control ◽  
Multi Agent ◽  
Two Phases ◽  
The Stability ◽  
Approach Phase

We consider hostile conflicts between two multi-agent swarms. First, we investigate the complex nature of a single pursuer attempting to intercept a single evader (1P-1E), and establish some rudimentary rules of engagement. We elaborate on the stability repercussions of these rules. Second, we extend the modelling and stability analysis between multi-agent swarms of pursuers and evaders. The present document considers only swarms with equal membership strengths for simplicity. This effort is based on a set of suggested momenta deployed on individual agents. Due to the strong nonlinearities, Lyapunov-based stability analysis is used. The control of a group pursuit is divided into two phases: the approach phase during which the two swarms act like individuals in the 1P-1E interaction; and the assigned pursuit phase where each pursuer is assigned to an evader. A dissipative control momentum was suggested in an earlier publication, which caused undesirable control chatter. This study introduces a distributed control logic which ameliorates the chatter problems considerably.

Study of Electric Field-Induced Evaporation Like Process and Nucleation in Nanoscale

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
M. B. Darshan ◽  
Pratyush Agarwal ◽  
Dhiraj Indana ◽  
Saikat Datta ◽  
Ravi Kumar ◽  
...  
Keyword(s):  
Electric Field ◽  
Water Surface ◽  
Temporal Evolution ◽  
Temperature Fluctuations ◽  
High Heat ◽  
Density Variation ◽  
Nonuniform Electric Field ◽  
Uniform Electric Field ◽  
Water Molecules ◽  
Dynamics Simulations

A proposal is made to demonstrate features of thermodynamic evaporation at the nanoscale using only an external electric field. The consequences of exposure to both uniform and nonuniform electric field on the water nanofilms are analyzed through molecular dynamics simulations. The temporal evolution of temperature and molecular nucleation under uniform electric field resembles evaporation at high heat. The temperature fluctuations of the system are analyzed from the density variation of the system, which has received no heat input from outside. Evaporation like process and nucleation from the water surface is described as a systematic polarization of the water molecules in the presence of electric field. The nucleation of the vapor bubble with a nonuniform electric field also shows similarity with heat-induced pool boiling. The reason behind isolated nucleation is analyzed from the temperature map of the system at different time instants. Possible surface instabilities due to the exposure of electric field on water nanolayer are also elaborated for both uniform and nonuniform cases.

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