The phase behavior of C(10)E(4)-oil-water systems at constant o/w ratio and variable temperature (fish diagram) has been investigated for several homologous oil families. The temperature T( *) and surfactant concentration C( *) at the critical point were determined for 10 n-alkanes varying from C(6) to C(28) as well as for a series of alkylcyclohexanes and alkylbenzenes. On the basis of T( *), equivalent alkane carbon numbers (EACN) were assigned to nonlinear alkanes, alkylbenzenes, and alkylcyclohexanes. The consistency of the method was shown by corroborating that the EACN values of oils previously investigated with other C(i)E(j) (dibutyl ether, squalane, isopropyl myristate, and dodecylbenzene) are the same when determined with C(10)E(4). The fact that two oils of different nature but with the same EACN (i.e., the same T( *)) do not exhibit the same C( *) is discussed in terms of monomeric solubility of the surfactant in the oil (CMC(oil)).
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http://dx.doi.org/10.1016/j.jcis.2006.07.004 | DOI Listing |
J Phys Chem B
November 2024
Department of Environmental and Safety Engineering, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China.
To enhance crude oil recovery under complex reservoir conditions and reduce the environmental impact of the oil displacement system, a biosurfactant lipid peptide (TH) was combined with four chemical surfactants. From these combinations, those capable of achieving an ultralow interfacial tension region (<10 mN/m) were selected. The selected surfactant mixtures were then combined with polyacrylamide (HPAM) to construct a surfactant-polymer binary oil displacement system.
View Article and Find Full Text PDFBMJ Open Qual
October 2024
Department of Pediatric Emergency Medicine, University of Florida College of Medicine, Gainesville, Florida, USA.
Background: The University of Florida (UF) Equal Access Clinic Network (EACN) is the largest student-run free healthcare clinic network in Florida. The UF EACN serves those who are underinsured or uninsured in Alachua County and its surrounding area. Nationally, average total clinic time per medical visit has been established to be 84 min.
View Article and Find Full Text PDFCureus
August 2024
Department of Emergency Medicine, University of Florida College of Medicine, Gainesville, USA.
Introduction: The University of Florida Equal Access Clinic Network (EACN) is the largest student-run free clinic (SRFC) network in Florida. This student-driven, continuous quality improvement (CQI) project is intended to decrease total patient visit length at Eastside clinic, one of EACN's primary care sites. The original median visit length of 126.
View Article and Find Full Text PDFJ Phys Chem A
August 2024
Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee Knoxville 310 Ferris Hall, 1508 Middle Drive, Knoxville, Tennessee 37996, United States.
The chemical properties of oils are vital in the design of microemulsion systems. The hydrophilic-lipophilic difference equation used to predict microemulsions' phase behavior expresses the oils' physiochemical properties as the equivalent alkane carbon number (EACN). The experimental determination of EACN requires knowledge of the temperature dependence of the microemulsion system and the effects of different surfactant concentrations.
View Article and Find Full Text PDFLangmuir
December 2023
Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S3E5, Canada.
The characteristic curvature (Cc), within the hydrophilic-lipophilic difference + net () - average () curvature (HLD-NAC) framework, is the dimensionless net curvature, -· ( is the surfactant's tail length parameter), that a surfactant acquires at the characteristic condition ( = 25 °C, no added cosurfactants, oil with an equivalent alkane carbon number (EACN) of zero and for ionic surfactants, a total salinity () of 1 g NaCl/100 mL). A recent article demonstrated the validity of the Cc concept, where was assessed via oil and water solubilization radii. Here, we assess from the characteristic length (ξ) obtained from the analysis of SAXS profiles of microemulsions produced at semicharacteristic conditions (characteristic condition but varying ).
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