Sphere tensiometry: an evaluation and critique

1976 ◽  
Vol 54 (6) ◽  
pp. 969-978 ◽  
Author(s):  
C. Huh ◽  
S. G. Mason

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.

Author(s):  
H. Samara ◽  
T. V. Ostrowski ◽  
F. Ayad Abdulkareem ◽  
E. Padmanabhan ◽  
P. Jaeger

AbstractShales are mostly unexploited energy resources. However, the extraction and production of their hydrocarbons require innovative methods. Applications involving carbon dioxide in shales could combine its potential use in oil recovery with its storage in view of its impact on global climate. The success of these approaches highly depends on various mechanisms taking place in the rock pores simultaneously. In this work, properties governing these mechanisms are presented at technically relevant conditions. The pendant and sessile drop methods are utilized to measure interfacial tension and wettability, respectively. The gravimetric method is used to quantify CO2 adsorption capacity of shale and gas adsorption kinetics is evaluated to determine diffusion coefficients. It is found that interfacial properties are strongly affected by the operating pressure. The oil-CO2 interfacial tension shows a decrease from approx. 21 mN/m at 0.1 MPa to around 3 mN/m at 20 MPa. A similar trend is observed in brine-CO2 systems. The diffusion coefficient is observed to slightly increase with pressure at supercritical conditions. Finally, the contact angle is found to be directly related to the gas adsorption at the rock surface: Up to 3.8 wt% of CO2 is adsorbed on the shale surface at 20 MPa and 60 °C where a maximum in contact angle is also found. To the best of the author’s knowledge, the affinity of calcite-rich surfaces toward CO2 adsorption is linked experimentally to the wetting behavior for the first time. The results are discussed in terms of CO2 storage scenarios occurring optimally at 20 MPa.


1978 ◽  
Vol 56 (6) ◽  
pp. 818-823 ◽  
Author(s):  
E. Bayramli ◽  
C. Huh ◽  
S. G. Mason

This paper is a supplement to an earlier one on the new absolute gravimetric method of measuring surface and interfacial tension which takes into account the effect of the wall in circular containers of finite radius which causes the liquid surface to dimple instead of remaining flat as in an unbounded system as assumed earlier.Using conventional capillarity theory, the basic principles for correcting force–displacement curves, called sphere-tensiograms, are derived. Numerical correction factors calculated from the theory for systems with perfect wetting (zero contact angle) for an experimentally realistic range of parameters, and corroborative experimental data are presented.


Surfactants ◽  
2019 ◽  
pp. 25-52
Author(s):  
Bob Aveyard

Capillarity reflects the action of interfacial tension and has been central to understanding intermolecular forces. When a liquid meets a solid surface (with contact angle θ‎) it forms a meniscus which is associated with the rise/depression of liquid in a capillary tube, hence the term capillarity. Interfacial tensions also determine how a liquid wets and adheres to a solid or another liquid. Liquid menisci are curved, and Young, Laplace, and Kelvin have all thrown light upon the properties of curved liquid surfaces. The Young–Laplace equation relates the pressure difference across a curved liquid interface to both the interfacial tension and curvature of the interface. Interfacial tension also gives rise to a dependence of the vapour pressure (and solubility) of a liquid on the curvature of its surface (e.g. drop radius), as expressed in the Kelvin equation. Common methods for measurement of interfacial tensions are described in an Appendix.


2008 ◽  
Vol 2008 (1) ◽  
pp. 785-789
Author(s):  
Karen M. Koran ◽  
Albert D. Venosa ◽  
Christopher Luedeker

ABSTRACT The U. S. Environmental Protection Agency (EPA) has developed a laboratory testing protocol to evaluate the effectiveness of surface washing agents (SWAs) to remove crude oil from a solid substrate. Variables were tested to determine their effect on SWA performance. The protocol was most sensitive to SWA:oil ratio (SOR) and rotational speed of mixing; it was not greatly affected by contact time, mixing time, or SWA concentration when total applied mass is constant. Interfacial tension and contact angle were measured for Prudhoe Bay Crude oil in the presence of six SWAs. SWAs were ranked based on 1) efficiency under the developed protocol, 2) ability to reduce interfacial tension and 3) ability to increase oil-substrate contact angle. In order for oil displacement to be thermodynamically favored, an SWA must have a lower interfacial tension with the substrate than does the oil. Using Young'S equation, the difference between the two solid-liquid interfacial tensions was calculated from the three phase contact angle and the interfacial tension between the two liquids. SWAs were ranked based on each of these criteria, and data were correlated with effectiveness under the protocol.


1967 ◽  
Vol 40 (4) ◽  
pp. 1246-1269 ◽  
Author(s):  
J. W. Vanderhoff ◽  
H. L. Tarkowski ◽  
M. C. Jenkins ◽  
E. B. Bradford

Abstract The Dillon, Matheson, and Bradford and the Brown hypotheses for the mechanism of film formation of latexes are extended, two latex particles in a drop of water being given as a model. As the water evaporates, the particles are brought together, so that their stabilizing layers are in contact and their further approach is hindered. The pressure forcing the particles together is increased by the further evaporation of water (that is, by the forces arising from the water air interfacial tension), until the stabilizing layers are ruptured and a polymer polymer contact is formed. Once this occurs, the pressure exerted upon the particles is increased further by the forces arising from the polymer water interfacial tension. Numerical values for the pressure exerted upon the particles are calculated as a function of latex particle size, degree of coalescence, and interfacial tensions both of water against air and polymer against water. Similar calculations with a latex particle coalescing against a flat surface (for example, a substrate) as a model demonstrate the importance of the contact angle between the polymer and the flat surface. The hypotheses developed are used to explain various experimental observations.


2020 ◽  
Vol 8 (1) ◽  
pp. 47-67
Author(s):  
Andrew Terhemen Tyowua ◽  
Stephen Gbaoron Yiase

The existence of contact angle hysteresis – the difference between the values of the advancing and receding contact angles – is evident in nature (e.g. sticking of rain drops to car windscreens and window panes) and many industrial processes (e.g. surface coating, spraying, and dyeing of fabrics). This phenomenon is often viewed as a nuisance, but it is advantageous in many processes including dip and spin coating, spraying, and painting. With the early theoretical framework of Thomas Young, Robert Wenzel, and A. B. D. Cassie and S. Baxter, describing the wettability of solid surfaces and by extension contact angle, contact angle hysteresis has been deeply investigated. We review here the various ways of measuring contact angle and, consequently, contact angle hysteresis as well as related theoretical models. The successes and limitations of these models are highlighted. We conclude with the advantages and disadvantages of contact angle hysteresis whose presence in many processes is often considered as a nuisance, especially when "coffee stain" forms from the evaporation of a volatile liquid drop containing nonvolatile components.


Author(s):  
V. Suganya ◽  
V. Anuradha

Encapsulation is a process of enclosing the substances within an inert material which protects from environment as well as control drug release. Recently, two type of encapsulation has been performed in several research. Nanoencapsulation is the coating of various substances within another material at sizes on the nano scale. Microencapsulation is similar to nanoencapsulation aside from it involving larger particles and having been done for a greater period of time than nanoencapsulation. Encapsulation is a new technology that has wide applications in pharmaceutical industries, agrochemical, food industries and cosmetics. In this review, the difference between micro and nano encapsulation has been explained. This article gives an overview of different methods and reason for encapsulation. The advantages and disadvantages of micro and nano encapsulation technology were also clearly mentioned in this paper.


2021 ◽  
Author(s):  
Xu-Guang Song ◽  
Ming-Wei Zhao ◽  
Cai-Li Dai ◽  
Xin-Ke Wang ◽  
Wen-Jiao Lv

AbstractThe ultra-low permeability reservoir is regarded as an important energy source for oil and gas resource development and is attracting more and more attention. In this work, the active silica nanofluids were prepared by modified active silica nanoparticles and surfactant BSSB-12. The dispersion stability tests showed that the hydraulic radius of nanofluids was 58.59 nm and the zeta potential was − 48.39 mV. The active nanofluids can simultaneously regulate liquid–liquid interface and solid–liquid interface. The nanofluids can reduce the oil/water interfacial tension (IFT) from 23.5 to 6.7 mN/m, and the oil/water/solid contact angle was altered from 42° to 145°. The spontaneous imbibition tests showed that the oil recovery of 0.1 wt% active nanofluids was 20.5% and 8.5% higher than that of 3 wt% NaCl solution and 0.1 wt% BSSB-12 solution. Finally, the effects of nanofluids on dynamic contact angle, dynamic interfacial tension and moduli were studied from the adsorption behavior of nanofluids at solid–liquid and liquid–liquid interface. The oil detaching and transporting are completed by synergistic effect of wettability alteration and interfacial tension reduction. The findings of this study can help in better understanding of active nanofluids for EOR in ultra-low permeability reservoirs.


KYAMC Journal ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 21-24
Author(s):  
Md Abdus Salam ◽  
Md Mahbub Alam ◽  
Rezwan Ahmed ◽  
Md Sultan Mahmud

Background: Tonsillectomy is one of the most common surgical procedures performed worldwide by otorhinolaryngologists for different indications. Tonsillectomy is often performed as day-case surgery, which increases the demands of a satisfactory postoperative pain control and a low risk of early postoperative bleeding. Objective: The aim of the study was to compare the Monopolar diathermy and Dissection methods of tonsillectomy and evaluate their advantages and disadvantages during surgery, convalescence. Materials and Methods: Two hundred children were recruited for this study during the period of five years from January, 2014 to December, 2018 at Otolaryngology department of Khwaja Yunus Ali Medical College and Hospital (KYAMCH). Subjects between the age of 5 and 25 years listed for tonsillectomy were included. Subjects were recommended not to have aspirin within the 2 weeks before surgery. Results: The mean duration of operation was found 10.6±0.4 minutes in group A and 17.0±0.7 minutes in group B. The difference was statistically significant (p<0.05) between two groups. At 1st day, 11(11.0%) patients had throat pain in group A and 23(23.0%) in group B. At 2nd day, 14(14.0%) patients had throat pain in group A and 25(25.0%) in group B. Which were statistically significant (p<0.05) between two groups. Conclusion: The monopolar diathermy tonsillectomy appears to cause less bleeding, postoperative pain and less time consuming in compare with the dissection tonsillectomy although patients experience slightly more pain than dissection Method. KYAMC Journal Vol. 10, No.-1, April 2019, Page 21-24


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