Many first generation expert systems in medicine assumed that a single fault was the cause of the patient''s problems. However, this is not always so and in the domain of gait analysis this is usually not the case. This work looks at an expert system for performing gait analysis on cerebral palsy patients. The system is able to handle cases where there are many interacting faults causing the patient''s gait deviations. A qualitative-torque model of gait is used as a framework for analyzing the patient''s disorders. This model allows the effects of individual faults to be examined and also explicitly captures the interaction between various faults. The incorporation of this model into an expert system leads to a more complete and robust expert system for gait analysis than any existing previously. The qualitative-torque model of gait models gait by using torque equations represented as incremental qualitative (IQ) algebra equations. Because everything is not known about the torques, the system has to make assumptions to arrive at some values. These assumptions are kept consistent by using an assumption-based truth maintenance system. The only part of the model specific to cerebral palsy is the set of heuristics used to score competing assumptions. Thus, the gait model developed for this system could easily be adapted for use in an expert system diagnosing gait disorders of any given etiology.

The Bartlesville Energy Research Center, in cooperation with American Petroleum Institute Research Project 60, used gel permeation chromatography (GPC) in the separation and characterization of the heavy ends of petroleum. The correlations are now being used to characterize oils from other fossil fuel sources such as coal, shale, and tar sands. By the use of retention-volume data for a few compounds, several fundamental parameters were developed and correlated. The parameters involved are expressed in terms of retention volume increments which are additive and allow precise calculation of molecular volumes, densities, and retention volumes of many compounds (without GPC experimentation) based upon retention-volume data on a few compounds. The result is an array of numerical values and groups of selective rules for their combinations. Heteroatomic molecules (N, S, and O analogs of hydrocarbons) could be included. The fundamental GPC parameter correlations can be extended and shown to be of extreme practical importance in characterizing saturate, monoaromatic, diaromatic, and polyaromatic-polar concentrates from 350/sup 0/ to 550/sup 0/C petroleum distillates. Lower boiling (200/sup 0/ to 350/sup 0/C) samples also have been analyzed by this method with excellent success.

Compositional data on Recluse, Wyo., crude oil, one of the most paraffinic crude oils, is given. These data are useful in optimizing petroleum processing methods for improved utilization of petroleum.

To obtain compositional information on both hydrocarbon and nonhydrocarbon components of crude oil and to develop suitable analytical methods applicable to any crude oil, the Bureau of Mines, through American Petroleum Institute Research Project 60 (API) RP 60), is studying in some detail the higher boiling fractions of five crude oils of different chemical composition and geological origin. To effectively process and use the heavy ends of petroleum it is necessary to develop suitable separation and characterization procedures not currently available. A systematic procedure developed by the Bureau of Mines uses techniques such as isothermal and molecular distillation, chemical treatment, silica-alumina gel chromatography, gel permeation chromatography and spectrometry. Using these techniques, the Bureau reports herein a detailed separation and characterization of 370/sup 0/ to 535/sup 0/C distillate from Gach Saran, Iran, crude oil. Such a systematic procedure, applicable to any crude oil, should be of value in selecting feedstocks and optimizing petroleum processing operations.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSeparation of high-boiling petroleum distillates using gradient elution through dual-packed (silica gel-alumina gel) adsorption columnsD. E. Hirsch, R. L. Hopkins, H. J. Coleman, F. O. Cotton, and C. J. ThompsonCite this: Anal. Chem. 1972, 44, 6, 915–919Publication Date (Print):May 1, 1972Publication History Published online1 May 2002Published inissue 1 May 1972https://doi.org/10.1021/ac60314a010RIGHTS & PERMISSIONSArticle Views320Altmetric-Citations103LEARN 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 (555 KB) Get e-Alerts Get e-Alerts

This paper presents compositional data on a sample of Prudhoe Bay, Alaska, crude oil and a description of the separation and identification methods used in the study.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSeparation of crude oil fractions by gel permeation chromatographyHarold J. Coleman, D. E. Hirsch, and J. E. DooleyCite this: Anal. Chem. 1969, 41, 6, 800–804Publication Date (Print):May 1, 1969Publication History Published online1 May 2002Published inissue 1 May 1969https://doi.org/10.1021/ac60275a028Request reuse permissionsArticle Views180Altmetric-Citations28LEARN 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 (541 KB) Get e-Alertsclose Get e-Alerts