Advantages and limitations of the grooved Wilhelmy plate

1970 ◽  
Vol 23 (9) ◽  
pp. 1789 ◽  
Author(s):  
HM Princen
Keyword(s):  
Detailed Analysis ◽  
Correction Factor ◽  
Capillary Condensation ◽  
Vapour Phase ◽  
Alternative Procedure ◽  
Interfacial Tensions ◽  
Measuring Surface ◽  
Wilhelmy Plate

A detailed analysis has been made of the grooved Wilhelmy plate as an instrument for measuring surface and interfacial tensions. It is shown, on the assumption of V-shaped vertical grooves, that the method can lead to errors if the weight of the dry plate is used as the reference force. In practical cases the error can be of the order of 1%. Quantitative expressions are given for the correction factor to be employed. It is also shown that no correction factor is required, providing one takes as the reference force the weight of the plate after it has come to equilibrium with the vapour phase, and capillary condensation of vapour in the grooves has taken place. This equilibrium will not readily be realized in practice, and an alternative procedure is proposed which utilizes the weight of the plate after it is detached from the liquid. The conclusions may also apply, at least semi-quantitatively, to randomly roughened, rather than regularly grooved, plates.

The determination of interfacial tensions with the Wilhelmy plate method

1971 ◽  
Vol 26 (9) ◽  
pp. 1479-1480 ◽  
Author(s):  
P.M. Heertjes ◽  
E.C. de Smet ◽  
W.C. Witvoet
Keyword(s):  
Plate Method ◽  
Interfacial Tensions ◽  
Wilhelmy Plate ◽  
Wilhelmy Plate Method

Surface and interfacial tensions from the profile of a sessile drop

1972 ◽  
Vol 329 (1579) ◽  
pp. 421-431 ◽  
Keyword(s):  
Thin Film ◽  
Correction Factor ◽  
Sessile Drop ◽  
Maximum Height ◽  
Gravitational Acceleration ◽  
Interfacial Tensions ◽  
Two Fluids ◽  
Intermediate Size ◽  
Surrounding Fluid ◽  
Sessile Drops

Sessile drops and captive bubbles resting at a plane solid surface but separated from the surface by a thin film of the surrounding fluid, appear to possess angles of contact of 180°. The limiting height, Z ∞ 180 of a very large sessile drop formed under these conditions is related to the interfacial tension, γ , by the expression γ = ¼∆ pg ( Z ∞ 180 ) 2 , where ∆ p is the density difference of the two fluids and g , the gravitational acceleration. As very large drops are not usually obtained experimentally the maximum height of a drop of intermediate size was measured and used in the equation with an appropriate correction factor. The correction factor was obtained from tables of the profiles of sessile drops. The correction factor is invariant for all values of γ , ∆ p and g . The method is tested experimentally and shown to agree with the results obtained by other methods for a number of widely differing systems. The reproducibility and sources of error are discussed.

scholarly journals On the calculation of surface tension from measurements of pendant drops

1948 ◽  
Vol 194 (1036) ◽  
pp. 1-16 ◽  
Keyword(s):  
Surface Tension ◽  
Interfacial Tensions ◽  
Measuring Surface ◽  
Pendant Drops

The calculations presented are an extension of the work of Bashforth & Adams (1883) to give the shapes of pendant drops of liquids for values of β from — 0.25 to — 0.6 at intervals of 0.025. The results have been used to calculate, to an accuracy of 0.001 to 0.01 %, the constants needed for measuring surface and interfacial tensions by the method suggested by Andreas, Hauser & Tucker (1938), which has thus been made independent of calibration.

Surface Energy and Capillary Pressure

2019 ◽  
pp. 110-139
Author(s):  
C. Mathew Mate ◽  
Robert W. Carpick
Keyword(s):  
Surface Energy ◽  
Capillary Pressure ◽  
Capillary Condensation ◽  
Solid Surfaces ◽  
Work Of Adhesion ◽  
Liquid Droplets ◽  
Surface Energies ◽  
Angle Measurements ◽  
Measuring Surface ◽  
Contact Angle Measurements

The energies associated with surfaces—surface energy, interfacial energy, surface tension, and work of adhesion—drive many surface and interfacial phenomena including tribological ones such as adhesion and friction. This chapter discusses the physical origins of surface energies for liquids and solids, and how the concepts of capillary pressure, capillary condensation, wetting, and work of adhesion are derived from surface energy. Further, this chapter covers the different methods for measuring surface energies, including the most common method for solid surfaces: contact angle measurements of liquid droplets on surfaces. This chapter also introduces how surface energies and surface tensions lead to adhesion and adhesion hysteresis between contacting surfaces, which is followed up in the subsequent chapters on surface forces.

IMPROVED DISPERSANT BASED ON MICROEMULSION TECHNOLOGY

1989 ◽  
Vol 1989 (1) ◽  
pp. 317-320
Author(s):  
Gerard P. Canevari ◽  
Jan Bock ◽  
Max Robbins
Keyword(s):  
Water Interface ◽  
Basic Study ◽  
Interfacial Tensions ◽  
Current State ◽  
Dispersed Oil ◽  
Wilhelmy Plate ◽  
Low Interfacial Tension ◽  
Overall Performance ◽  
Oil Water ◽  
The Impact

ABSTRACT An initial basic study focused on the interaction between dispersant surfactants and the oil-water interface. In essence, the study identified criteria to explain why a good dispersant is effective and why a poor dispersant is ineffective. The dynamic behavior of the oil-water interface, after the addition of the dispersant, was continuously monitored by a modified Wilhelmy plate device. This procedure provided much insight on the impact of the dispersant at the oil-water interface. One key finding of this study concerned the conditions for achieving very low interfacial tensions. It is known in microemulsion technology that a microemulsion formed by specific surfactants exhibits ultra-low interfacial tension against either oil or water. Microemulsion phase behavior studies then established that some specific surfactants, which form a certain type of microemulsion, are also highly effective dispersants, more effective than current state-of-the-art products. This improvement results in the formation of much finer dispersed oil droplets generated by a very minimum and lower level of energy. This paper will review the results of the basic study and the subsequent formulation of an improved dispersant. Laboratory and field data evaluating and supporting the improved overall performance will be presented.

Sphere tensiometry: an evaluation and critique

1976 ◽  
Vol 54 (6) ◽  
pp. 969-978 ◽  
Author(s):  
C. Huh ◽  
S. G. Mason
Keyword(s):  
Contact Angle ◽  
Interfacial Tension ◽  
Simultaneous Measurement ◽  
Gravimetric Method ◽  
Sphere Surface ◽  
Interfacial Tensions ◽  
Advantages And Disadvantages ◽  
Simultaneous Measurements ◽  
Measuring Surface ◽  
The Difference

An absolute gravimetric method of measuring surface and interfacial tensions of liquids by pulling a sphere through the interface is examined. The method also permits simultaneous measurement of the contact angle of the liquid on the sphere surface; this enables corrections to be made for incomplete wetting of the solid by liquids in measuring the interfacial tension, a feature which the conventional ring and plate methods lack. Simultaneous measurements of the interfacial tension and the difference in phase densities across the interface are in principle also possible. Preliminary experimental results are presented, and the advantages and disadvantages of the method are critically discussed.

Measuring Surface Forces

2019 ◽  
pp. 234-258
Author(s):  
C. Mathew Mate ◽  
Robert W. Carpick
Keyword(s):  
Capillary Condensation ◽  
Surface Force ◽  
Liquid Films ◽  
Atomic Level ◽  
Surface Forces ◽  
Atomic Force ◽  
Measuring Surface ◽  
Frictional Forces ◽  
Repulsive Forces ◽  
Small Separation

This chapter focuses on the two experimental techniques—the surface force apparatus (SFA) and the atomic force microscope (AFM)—that are commonly used for measuring molecular level forces that act between two surfaces at small separation distances. The first part of this chapter covers the fundamental principles of SFA and AFM design. The second half of this chapter illustrates the application of AFM to measuring surface forces with examples the measurement of van der Waals forces, atomic level repulsive forces, frictional forces, electrostatic double-layer forces, and meniscus forces from liquid films and from capillary condensation.

Characterization of GaAs/AlGaAs quantum wells and quantum wires by chemical lattice imaging

1994 ◽  
Vol 52 ◽  
pp. 736-737
Author(s):  
A. Carlsson ◽  
J.-O. Malm ◽  
A. Gustafsson
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Quantum Wires ◽  
Vapour Phase ◽  
Quantitative Information ◽  
Lattice Imaging ◽  
Vapour Phase Epitaxy ◽  
Metalorganic Vapour Phase Epitaxy ◽  
High Resolution Images

In this study a quantum well/quantum wire (QW/QWR) structure grown on a grating of V-grooves has been characterized by a technique related to chemical lattice imaging. This technique makes it possible to extract quantitative information from high resolution images.The QW/QWR structure was grown on a GaAs substrate patterned with a grating of V-grooves. The growth rate was approximately three monolayers per second without growth interruption at the interfaces. On this substrate a barrier of nominally Al0.35 Ga0.65 As was deposited to a thickness of approximately 300 nm using metalorganic vapour phase epitaxy . On top of the Al0.35Ga0.65As barrier a 3.5 nm GaAs quantum well was deposited and to conclude the structure an additional approximate 300 nm Al0.35Ga0.65 As was deposited. The GaAs QW deposited in this manner turns out to be significantly thicker at the bottom of the grooves giving a QWR running along the grooves. During the growth of the barriers an approximately 30 nm wide Ga-rich region is formed at the bottom of the grooves giving a Ga-rich stripe extending from the bottom of each groove to the surface.

Prosodic Impairment Associated With Traumatic Brain Injury

2009 ◽  
Vol 19 (3) ◽  
pp. 97-102
Author(s):  
Billy Irwin
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Detailed Analysis ◽  
Acoustic Characteristics ◽  
Individual Variations

Abstract Purpose: This article discusses impaired prosody production subsequent to traumatic brain injury (TBI). Prosody may affect naturalness and intelligibility of speech significantly, often for the long term, and TBI may result in a variety of impairments. Method: Intonation, rate, and stress production are discussed in terms of the perceptual, physiological, and acoustic characteristics associated with TBI. Results and Conclusions: All aspects of prosodic production are susceptible to the effects of damage resulting from TBI. There are commonly associated prosodic impairments; however, individual variations in specific aspects of prosody require detailed analysis.

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