Month

The Message, Volume 35, April 30, 1999 (open access)

The Message, Volume 35, April 30, 1999

Newsletter of Congregation Beth Yeshurun in Houston, including news and events, upcoming services, member announcements, editorials, and other information of interest to congregants.
Date: April 30, 1999
Creator: Congregation Beth Yeshurun (Houston, Tex.)
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
PETROLEUM RESIDUA SOLUBILITY PARAMETER/POLARITY MAP: STABILITY STUDIES OF RESIDUA PYROLYSIS (open access)

PETROLEUM RESIDUA SOLUBILITY PARAMETER/POLARITY MAP: STABILITY STUDIES OF RESIDUA PYROLYSIS

A new molecular weight/polarity map based on the Scatchard-Hildebrand solubility equation has been developed for petroleum residua. A series of extractions are performed with solvents of increasing solubility parameter, and the fractions are analyzed by vapor pressure osmometry for number average molecular weight and by analytical-scale size exclusion chromatography for molecular weight spread. Work was performed for a heavy oil material subjected to three increasing severities of thermal treatment prior to and through the onset of coke formation. The results are diagnostic of the layers of solvations by resin-type molecules around a central asphaltene core. Two additional stability diagnostic methods were also used. These were the Heithaus titration ''P-index'' and Gaestel ''G'' index, which have been applied to paving asphalts for decades. The Heithaus titration involves the titration of three toluene solutions of a residuum at three concentrations with a poor solvent, such as isooctane, to the point of asphaltene flocculation. In the present work, the significance of the data are developed in terms of the Hildebrand solubility parameter. The Heithaus results are combined with data from the new molecular weight/polarity map. The solubility parameters for the toluene-soluble asphaltene components are measured, and the solubility parameters of the maltenes can …
Date: April 30, 1999
Creator: Schabron, John F.; Pauli, A. Troy & Joseph F. Rovani, Jr.
Object Type: Report
System: The UNT Digital Library
The Express-Star (Chickasha, Okla.), Ed. 1 Friday, April 30, 1999 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Friday, April 30, 1999

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: April 30, 1999
Creator: Bush, Kent
Object Type: Newspaper
System: The Gateway to Oklahoma History
Dallas Voice (Dallas, Tex.), Vol. 15, No. 52, Ed. 1 Friday, April 30, 1999 (open access)

Dallas Voice (Dallas, Tex.), Vol. 15, No. 52, Ed. 1 Friday, April 30, 1999

Weekly newspaper from Dallas, Texas that includes local, state, and national news and advertising of interest to the Lesbian, Gay, Bisexual, and Transgender (LGBT) community.
Date: April 30, 1999
Creator: Vercher, Dennis
Object Type: Newspaper
System: The UNT Digital Library