Cassie Equation Research Articles

Modification of the Cassie equation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModification of the Cassie equationJaroslaw Drelich and Jan D. MillerCite this: Langmuir 1993, 9, 2, 619–621Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published inissue 1 February 1993https://doi.org/10.1021/la00026a043RIGHTS & PERMISSIONSArticle Views456Altmetric-Citations53LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (351 KB) Get e-Alerts Get e-Alerts

Contact angles on particles and plates

Contact angles on partially methylated quartz plates and particles of known surface coverage have been measured as a function of surface coverage and compared with predictions based on the Cassie equation. Advancing and receding water-contact angles on quartz plates have been determined by the captive-bubble and sessile-drop methods. Advancing water-contact angles have been measured on quartz particles using the Washburn equation. Both advancing and receding contact angles on methylated quartz plates are in good agreement with predictions based on the Cassie equation. Advancing water-contact angles measured on methylated quartz particles are in good agreement with Cassie equation predictions up to surface coverages of about 70% and angles of approximately 70°, above which the measured angles are less than anticipated.

Contact angles on particles and plates

Contact angles on partially methylated quartz plates and particles of known surface coverage have been measured as a function of surface coverage and compared with predictions based on the Cassie equation. Advancing and receding water-contact angles on quartz plates have been determined by the captive-bubble and sessile-drop methods. Advancing water-contact angles have been measured on quartz particles using the Washburn equation. Both advancing and receding contact angles on methylated quartz plates are in good agreement with predictions based on the Cassie equation. Advancing water-contact angles measured on methylated quartz particles are in good agreement with Cassie equation predictions up to surface coverages of about 70% and angles of approximately 70°, above which the measured angles are less than anticipated.

Behavior of Switching Arc in Low-Voltage Limiter Circuit Breakers

The noteworthy increase in the present low-voltage circuitbreaker capacity implies that these products must be able to dramatically reduce the short-circuit currents in electric installations. This important current limitation can only be obtained by rapidly inducing an arc voltage in the circuit breaker, that opposes the mains voltage. A preliminary computer calculation shows that the arc voltage, and in particular the immobility time of the arc on the contacts, is very important for the quality of the limitation. Electric tests, carried out with constant or alternating current, made with an experimental device, clearly show the influence on the stagnation time of the contact opening speed and of the nature of the contact materials. The speed during breaking, which is constant, ranges between 2 m/s and 13 m/s (current publications are limited to 5 m/s). The contact materials under survey have been copper and silver, taken as references, and for the first time silver cadmium oxide as breaking material in circuit breakers. Tests have resulted in a semiempiric arc voltage model, deducted from a Cassie equation, extended to an arc being stretched. Solving by means of a computer the equation governing a break, for this arc voltage model, makes it possible to know beforehand with great precision the performances of a product.

Characterization of glass, quartz, and fused silica capillary column surfaces from contact-angle measurements

This paper describes the systematic characterization of glass and the newly introduced fused silica and quartz capillary columns from surface wettability measurements. Common gas chromatographic stationary phases were used in capillary-rise measurements at temperatures up to 300°C. By construction of Zisman plots and using the Cassie equation, the relative surface concentrations of wettable and non-wettable groups were determined. By application of the Fowkes equation, the dispersion force component of the surface energy was investigated. The influence of various surface treatments such as leaching, silylation, and polymeric film formation are discussed. Wettability measurements were also used to evaluate the thermostability of various treated surfaces and to compare the surface properties of glass, quartz, and fused silica. The wettability of the surfaces with selected stationary phases as a function of temperature is also discussed.

The Apparent Contact Angle of Liquids on Finely-Grooved Solid Surfaces-A SEM Study

Abstract A finely parallel-grooved nitrocellulose surface has been employed as a model to study by scanning electron microscopy the influence of roughness on the spreading equilibrium of liquid drops. The Cassie and Baxter equation for spherical drops on a composite interface was experimentally confirmed with mercury and a similar equation derived for a cylindrical drop has also been shown to be approximately valid for liquid polyphenylether. The observed drop shapes have been explained and the importance of groove edges demonstrated. Direct measurements of the microscopic contact angle of mercury locally on the grooved surfaces were found to be approximately the same for the smooth ungrooved surface.

The wetting of thin films of organo-bentonite complexes

The wetting by water of thin films of the decyl-, dodecyl-, tetradecyl-, hexadecyl-, and octadecylamine complexes of Wyoming bentonite was studied. The films were formed by evaporation, adsorption, and Langmuir-Blodgett (L.B.) techniques. Advancing contact angles averaged about 4° higher for evaporated films than for adsorbed or L.B. films. Hysteresis was high (30°–40°) and receding angles were less reproducible than advancing angles. Advancing angle behavior could be fitted by Cassie's equation for the range of surface coverages studied.

Arc Cooling and Short Line Fault Interruption

This paper covers the derivation of two sets of short line fault equations for the maximum rate of rise of recovery voltage (RRRV) characteristic of gas blast interrupters. The assumption that the electrical conductivity is proportional to the heat flux potential leads to a integral equation for post-arc current, a critical thermal time constant and the first set of RRRV equations. The assumption that the electrical conductivity varies exponentially with the heat flux potential leiads to the equation and the second set of RRRV equations. For both sets of equations it is shown that the maximum RRRV is (a) approximately proportional to the gas pressure; (b) proportional to the effective nozzle arc length at current zero and the number of series breaks; (c) proportional to temperature dependent coefficients which are functions of gas properties; and (d) inversely proportional to (dI/dt)m where m=3/2 and 1 for the Cassie and Mayr RRRV equations, respectively. These equations are complementary and serve as first-order limits on the interrupting capability of gas blast interrupters.