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182. Fabrication of graphite for use as a skeletal prosthesis
696
ABSTRACTS
behavior of cancerous organs during cremation crystallites, are amorphous to X-rays.
has been observed.
The carbons,
containing
ash as
181. First compatibility tests of ORNL graphite G. H. Kenner (Dept. of Ceramic Engineering and College of Veterinary Medicine, University of Illinois, UTbana, Z&n&, W. S. Williams (Dept. of Ceramic Engirxering and Dept. ofPhysics,University of Illinois, Urbana, ~1~~) and W. P. Eatherly (~~a~ and Ceram&s Division, Oak Ridge N~.~l Ligate, Oak Ridge, Toffee). Because of the compatibility of carbon with the human body it has great attraction for surgical implant purposes. A new isotropic fine-g-rained graphite with superior strength has been produced at the Oak Ridge National Laboratory. Plugs of l/8 in. in diameter were inserted in holes drilled in the proximal femur of rabbits and left for one year. Examination by microradiography and optical microscopy indicated no irritation or encapsulation. Further tests of ORNL graphite with linear pores are in progress for study of bone ingrowth and mineralization. 182. Fabrication of graphite for use as a skeletal prosthesis* J. M. Robbins, W. P. Eatherly and D. E. Rosson (Metals an.4 Ceramics DivaSion,Oak Ridge Naval Laboratory, Oak Ridge, Tennessee). Porous graphite with the presumed required structure for osteon penetration has been made at ORNL. We have used fugitive and etchable fibers to achieve ordered circular pores of 100-150 pm in diameter covering up to 50 per cent of the exposed surfaces. These are adequate to initiate in vivo experiments. *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation.
183. Mehins and carbons* Y. T. Thathachari (Dept. ofD~to~~, U~iv~~~ of~al~~~, San Fran~co, C~~~~~). Melanins are brown-black polymeric pigments found in most forms of life. They are known to be made up of either planar molecules of molecules with planar subgroups. Carefully recorded X-ray diffraction data of a number of natural and synthetic melanins contained a dominant peak at s = 2 sin B/h = O-3 A-‘, a less dominant one at s = 0.9 A-’ and a shoulder in the region s = 0.4 A-‘-O*6 A-‘. The positions of the two peaks remained practically unchanged whatever the source of the melanins or their mode of synthesis. The experimental data were compared with the transforms computed for the different monomers of melanins and for all sterically allowed mutual orientations of pairs of bonded as well as nonbonded monomers. The results clearly linked the peak at s = 0.9 A-l with the individual monomers and the O-3 A-’ with the presence of parallel layers 3.4 A apart. These in turn suggest the presence peakatsz of a short range order in these materials. eoncept~~~~ the melanin structure can be derived by the distion of the graphite lattice. This results in the smearing out of many features of the graphite diffraction except the (002) and (11) bands which can be recognized as the 0.3 %, -* and 0.9 A-l peaks of melanin& Many of the known properties of melanins, including their black color and high density (as compared to most biopolymers), are probably related to the short range order as in carbons. *This work was supported in part by N.I.H. Research, Stanford University.
Grant CA 12043-01 and by the facilities of the Center for Materials
184. Estimation of electrode quality by use of model arc furnace M. Okamura, M. Watanabe, K. Usui and J_ Kon @howa Denko K.K., Omachi Works Nagano-ken, 398 Japan). The effects of the arc upon the electrode in an arc furnace for steel making were observed using a high-speed camera. Precise experiments have been carried out under the state of a ‘low atmospheric temperature arc’, with a model arc furnace having a current capacity of 30 kA and using a 12 in. electrode. 185. De.terminationof electric current capacity of electrode by means of fracture with electric current M. Okamura and J. Kon (Show Denko K.K., Omachi Works, Nagano-ken, 398Japan). Graphite specimens were fractured with an electric current for the purpose of determining the electric current capacity of electrodes. Furthermore, the change in temperature and thermal stress distribution in the specimen according to the elapsed time were calculated with an electronic computer, and the results coincided with the results of the experiment.
ABSTRACTS
behavior of cancerous organs during cremation crystallites, are amorphous to X-rays.
has been observed.
The carbons,
containing
ash as
181. First compatibility tests of ORNL graphite G. H. Kenner (Dept. of Ceramic Engineering and College of Veterinary Medicine, University of Illinois, UTbana, Z&n&, W. S. Williams (Dept. of Ceramic Engirxering and Dept. ofPhysics,University of Illinois, Urbana, ~1~~) and W. P. Eatherly (~~a~ and Ceram&s Division, Oak Ridge N~.~l Ligate, Oak Ridge, Toffee). Because of the compatibility of carbon with the human body it has great attraction for surgical implant purposes. A new isotropic fine-g-rained graphite with superior strength has been produced at the Oak Ridge National Laboratory. Plugs of l/8 in. in diameter were inserted in holes drilled in the proximal femur of rabbits and left for one year. Examination by microradiography and optical microscopy indicated no irritation or encapsulation. Further tests of ORNL graphite with linear pores are in progress for study of bone ingrowth and mineralization. 182. Fabrication of graphite for use as a skeletal prosthesis* J. M. Robbins, W. P. Eatherly and D. E. Rosson (Metals an.4 Ceramics DivaSion,Oak Ridge Naval Laboratory, Oak Ridge, Tennessee). Porous graphite with the presumed required structure for osteon penetration has been made at ORNL. We have used fugitive and etchable fibers to achieve ordered circular pores of 100-150 pm in diameter covering up to 50 per cent of the exposed surfaces. These are adequate to initiate in vivo experiments. *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation.
183. Mehins and carbons* Y. T. Thathachari (Dept. ofD~to~~, U~iv~~~ of~al~~~, San Fran~co, C~~~~~). Melanins are brown-black polymeric pigments found in most forms of life. They are known to be made up of either planar molecules of molecules with planar subgroups. Carefully recorded X-ray diffraction data of a number of natural and synthetic melanins contained a dominant peak at s = 2 sin B/h = O-3 A-‘, a less dominant one at s = 0.9 A-’ and a shoulder in the region s = 0.4 A-‘-O*6 A-‘. The positions of the two peaks remained practically unchanged whatever the source of the melanins or their mode of synthesis. The experimental data were compared with the transforms computed for the different monomers of melanins and for all sterically allowed mutual orientations of pairs of bonded as well as nonbonded monomers. The results clearly linked the peak at s = 0.9 A-l with the individual monomers and the O-3 A-’ with the presence of parallel layers 3.4 A apart. These in turn suggest the presence peakatsz of a short range order in these materials. eoncept~~~~ the melanin structure can be derived by the distion of the graphite lattice. This results in the smearing out of many features of the graphite diffraction except the (002) and (11) bands which can be recognized as the 0.3 %, -* and 0.9 A-l peaks of melanin& Many of the known properties of melanins, including their black color and high density (as compared to most biopolymers), are probably related to the short range order as in carbons. *This work was supported in part by N.I.H. Research, Stanford University.
Grant CA 12043-01 and by the facilities of the Center for Materials
184. Estimation of electrode quality by use of model arc furnace M. Okamura, M. Watanabe, K. Usui and J_ Kon @howa Denko K.K., Omachi Works Nagano-ken, 398 Japan). The effects of the arc upon the electrode in an arc furnace for steel making were observed using a high-speed camera. Precise experiments have been carried out under the state of a ‘low atmospheric temperature arc’, with a model arc furnace having a current capacity of 30 kA and using a 12 in. electrode. 185. De.terminationof electric current capacity of electrode by means of fracture with electric current M. Okamura and J. Kon (Show Denko K.K., Omachi Works, Nagano-ken, 398Japan). Graphite specimens were fractured with an electric current for the purpose of determining the electric current capacity of electrodes. Furthermore, the change in temperature and thermal stress distribution in the specimen according to the elapsed time were calculated with an electronic computer, and the results coincided with the results of the experiment.