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Binder materials modified by sulfur
Abstracts irradiated to various doses. The peak is a lambda-type phase transition of the antiferromagnetically interacting fraction of randomly distributed localized spins. The linear temperature term and its relation to this effect are also discussed.
neutron
21. Relation between thermal and electrical conductivities of fast neutron irradiated reactor graphite W. Van Witzenburg and H. J. Veringa (Reactor Centrum Nederland, Petten, The Netherlands). No short abstract submitted. 22. A second low temperaturepeak in the specificbeat of a soft carbon? A. S. Vagh and S. Mrozowski (NASA Lewis Research Center, Cleveland, OH and Ball State University, Muncie, IN). Using a dilution refrigerator, the specific heat measurements were extended down to O.OS’K.For a sample of soft carbon heattreated to 1250°Cin addition to the known first peak at 064”K, an even stronger but very similar in appearance second peak at 0*32”Kwas found. Work on other carbon samples is in preparation. (No long abstract submitted.) tSupported by the National Science Foundation. IU. CARBONIZATIONAND GRAPHITIZATION 23. Hot-stage microscopy of mesopbase pitches R. T. Lewis (Union Carbide Corporation, Parma, OH 44130). Hot-stage microscopy has been used to directly
observe the mesophase development in pitch at temperatures up to 450°C. Observations of melting behavior have been used to estimate the viscosities of the isotropic and the anisotropic phases in mesophase pitches. In some pitches, a portion of the mesophase present at a given temperature has been observed to dissolve in the isotropic phase at higher temperatures. 24. Binder materials modified by sulfur E. Fitzer and H. Tillmanns (Universitat Karlsruhe, W. Germany). The paper describes the effect of sulfur additions to coaltar binder pitch up to 33 wt% on the baking behaviour and the bulk properties of molded laboratory samples with pitch coke as filler. The results, which confirm the known effect on the increase of strength but show also a decrease of electrical resistivity are discussed in view of systematic and basic research on the pyrolysis chemistry with binder modified by added elemental sulfur. 25. Linear free energy relationships in carbon film deposition D. B. Murphy and R. W. Carroll (Herbert H. Lehman College (CLJNY), Bronx, NY 10468). The kinetics of carbon film deposition has been studied between 1063and 1373K. Two linear free energy relationships have been found, one for cyclic, and the second for straight-chain hydrocarbons (excluding methane). Within each series the reaction mechanism is similar and involves a slow step on the carbon surface.
545
26. Mechanismsof formation of needle coke J. L. White, G. Johnson and J. E. Zimmer (The Aerospace Corporation, P.O. Box 92957, Los Angeles, CA 90009). The mesophase microstructures formed in the
pyrolysis of a petroleum pitch and a decant oil were studied by polarized-light microscopy. Mesophase fibers were also drawn from partially transformed pitch. The observations show that the fine fibrous bands of needle coke result from plastic deformation as the mesophase hardens. 27. The structure of needle coke J. E. Zimmer and J. L. White (The Aerospace Corporation,
P.O. Box 92957,. Los Angeles, CA 9ooo9).
The microconstituent uniquely characteristic of needle coke acicular particles has been identified as the fine fibrous structure consisting of folded, corrugated arrays of graphitic layers which are straight and parallel along the particle axis. These fine fibrous bands comprise only a moderate fraction of typical delayed needle coke. 28. Hydrogendesorption:a possible rate determining step in pyrocarbonformation J. Hill and K. R. Norman (AWRE, MOD(PE), Aldermaston, Berks, UK). Pyrocarbon has been deposited from methane onto a resistively heated carbon string with a large surface area. The effect of methane pressure on the initial deposition rate is consistent with hydrogen desorption being rate controlling. The whole deposition process could be described by linear weight gain vs log (time) plots. 29. Factors controlling the mesophase microstructure produced during pyrolysis of aromatic hydrocarbons D. 0. Rester (Naval Surface Weapons Center, Silver Spring, MD 20910). Mesophase formation in hydrocarbons has been studied using test tube pyrolysis methods and hot stage microscopy. Direct observation of mesophase formation and growth during pyrolysis revealed that gas bubble percolation produces coalescence and deformation of mesophase droplets. These results will be discussed in relation to needle coke production. 30. Formationand structureof coke from non-cokingcoals by carbonization in hydrogen B. N. Nandi, M. Ternan, B. I. Parsons and D. S. Montgomery (Canada Centre for Mineral & Energy Technology, Ottawa, Canada). The coking properties can be restored to non-coking coals of all ranks by partial hydrogenation at appropriate temperatures and pressures. Sufficient fluidity was developed by this process to form an agglomerated coke. Microscopic examination reveals the formation of coarse and grain mosaic structure in the cokes. Infrared analyses suggests that the opening of the oxygen ether linkages produced the development of the coking properties. 31. Inhomogeneousmodel for carbonization F. Carmona and P. Delhaes (Centre de Recherches Paul Pascal, 33405talence, France). An inhomogeneous model for the “semi-conductor-to-metal” transition in
neutron
21. Relation between thermal and electrical conductivities of fast neutron irradiated reactor graphite W. Van Witzenburg and H. J. Veringa (Reactor Centrum Nederland, Petten, The Netherlands). No short abstract submitted. 22. A second low temperaturepeak in the specificbeat of a soft carbon? A. S. Vagh and S. Mrozowski (NASA Lewis Research Center, Cleveland, OH and Ball State University, Muncie, IN). Using a dilution refrigerator, the specific heat measurements were extended down to O.OS’K.For a sample of soft carbon heattreated to 1250°Cin addition to the known first peak at 064”K, an even stronger but very similar in appearance second peak at 0*32”Kwas found. Work on other carbon samples is in preparation. (No long abstract submitted.) tSupported by the National Science Foundation. IU. CARBONIZATIONAND GRAPHITIZATION 23. Hot-stage microscopy of mesopbase pitches R. T. Lewis (Union Carbide Corporation, Parma, OH 44130). Hot-stage microscopy has been used to directly
observe the mesophase development in pitch at temperatures up to 450°C. Observations of melting behavior have been used to estimate the viscosities of the isotropic and the anisotropic phases in mesophase pitches. In some pitches, a portion of the mesophase present at a given temperature has been observed to dissolve in the isotropic phase at higher temperatures. 24. Binder materials modified by sulfur E. Fitzer and H. Tillmanns (Universitat Karlsruhe, W. Germany). The paper describes the effect of sulfur additions to coaltar binder pitch up to 33 wt% on the baking behaviour and the bulk properties of molded laboratory samples with pitch coke as filler. The results, which confirm the known effect on the increase of strength but show also a decrease of electrical resistivity are discussed in view of systematic and basic research on the pyrolysis chemistry with binder modified by added elemental sulfur. 25. Linear free energy relationships in carbon film deposition D. B. Murphy and R. W. Carroll (Herbert H. Lehman College (CLJNY), Bronx, NY 10468). The kinetics of carbon film deposition has been studied between 1063and 1373K. Two linear free energy relationships have been found, one for cyclic, and the second for straight-chain hydrocarbons (excluding methane). Within each series the reaction mechanism is similar and involves a slow step on the carbon surface.
545
26. Mechanismsof formation of needle coke J. L. White, G. Johnson and J. E. Zimmer (The Aerospace Corporation, P.O. Box 92957, Los Angeles, CA 90009). The mesophase microstructures formed in the
pyrolysis of a petroleum pitch and a decant oil were studied by polarized-light microscopy. Mesophase fibers were also drawn from partially transformed pitch. The observations show that the fine fibrous bands of needle coke result from plastic deformation as the mesophase hardens. 27. The structure of needle coke J. E. Zimmer and J. L. White (The Aerospace Corporation,
P.O. Box 92957,. Los Angeles, CA 9ooo9).
The microconstituent uniquely characteristic of needle coke acicular particles has been identified as the fine fibrous structure consisting of folded, corrugated arrays of graphitic layers which are straight and parallel along the particle axis. These fine fibrous bands comprise only a moderate fraction of typical delayed needle coke. 28. Hydrogendesorption:a possible rate determining step in pyrocarbonformation J. Hill and K. R. Norman (AWRE, MOD(PE), Aldermaston, Berks, UK). Pyrocarbon has been deposited from methane onto a resistively heated carbon string with a large surface area. The effect of methane pressure on the initial deposition rate is consistent with hydrogen desorption being rate controlling. The whole deposition process could be described by linear weight gain vs log (time) plots. 29. Factors controlling the mesophase microstructure produced during pyrolysis of aromatic hydrocarbons D. 0. Rester (Naval Surface Weapons Center, Silver Spring, MD 20910). Mesophase formation in hydrocarbons has been studied using test tube pyrolysis methods and hot stage microscopy. Direct observation of mesophase formation and growth during pyrolysis revealed that gas bubble percolation produces coalescence and deformation of mesophase droplets. These results will be discussed in relation to needle coke production. 30. Formationand structureof coke from non-cokingcoals by carbonization in hydrogen B. N. Nandi, M. Ternan, B. I. Parsons and D. S. Montgomery (Canada Centre for Mineral & Energy Technology, Ottawa, Canada). The coking properties can be restored to non-coking coals of all ranks by partial hydrogenation at appropriate temperatures and pressures. Sufficient fluidity was developed by this process to form an agglomerated coke. Microscopic examination reveals the formation of coarse and grain mosaic structure in the cokes. Infrared analyses suggests that the opening of the oxygen ether linkages produced the development of the coking properties. 31. Inhomogeneousmodel for carbonization F. Carmona and P. Delhaes (Centre de Recherches Paul Pascal, 33405talence, France). An inhomogeneous model for the “semi-conductor-to-metal” transition in