Structures due to friction in mechanical working processes
Citation for published version (APA):
Dijck, van, J. A. B., & Dautzenberg, J. H. (1987). Structures due to friction in mechanical working processes.
Ultramicroscopy, 21(2), 190-190.
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Published: 01/01/1987
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measurements. Bulk fabric analysis would only be practical with computer- ised "on-line" analysis of diffraction patterns and grain orientations.
STRUCTURES DUE TO FRICTION IN MECHANICAL WORKING PROCESSES
J.A.B. van Dijck and J.H. Dautzenberg
Laboratorium for Forming Technology, university of Technology, Eindhoven
The increase of miniaturisation and production automation together with a higher demand for accuracy of newly dev- eloped products requires, among other things, a higher surface quality for the parts made mechanically. An aspect of this is the surface roughness. It canbe divided in two sections--one caused by the process which is present directly after the working process. The second section arises some time after the pro- cess is completed. It is very important in the production of optical components. This roughness is caused by the residual stresses in the work surface that orig- inate from dry sliding friction. In order to get more information, we took thin foils of the contact surface and cross-sections through it. This was done for several different metals and different working processes such as sanding, grinding and single-point dia- mond cutting. They showed plastic de-
formation structures which diminished inwards from the contact surface.
In the contact surface itself, the structure seemed to be recrystallized in most cases. This agrees with resid- ual stress measurements made with X-rays. Here, in most cases, it increases up to a maximum just below the contact surface and is followed by a decrease.
Provisional results show that the same effect occurs repeatedly in all mechanically worked metal surfaces when
submitted to dry sliding friction.
DEPOSITION OF MICROORGANISMS ON HUMAN PROSTHESIS MATERIAL, A SEM STUDY OF A SILICONE VOICE PROSTHESIS AND A H.E.M.A. CONTACT LENS
F. Dijk, H.F. Mahieu* andW.L. Jongebloed
Centre for Med. Electron Microscopy,
University of Groningen: *Ear, Nose
and Throat Clinic of the Acad. Hospital Groninqen
The use of a voice prosthesis of the "Groningen-type" in post-laryngectomy voice rehabilitation has proved to be successful. Depositions found on the esophageal surface of the silicone but- ton are thought to be responsible for malfunction of the valve mechanism af- ter a certain time. Contact lenses of the H.E.M.A. type are generally pre- scribed in ophthalmology. Deposition of microorganisms, due to improper cleaning, can impair vision and threat- en healthy cornea condition.
Both voice prosthesis and contact lens had been washed in buffer solution prior to fixation in 2% GA (4 h) and 1% 0~04 (8 h), both in cat. buffer, de- hydrated in ethanol and dried either by C.P.D. (button) or via D.M.P. (contact lens). Finally the samples were sput- tercoated with Au (+15 nm) and examined at either 15 or 25 kV.
The esophageal side of the voice prosthesis showed a dense vegetation of yeast buds and mycelia of the candida type. Invasive growth of the vegeta- tion into the silicon material took place. Expanding forces of the yeast vegetation into the valve areas caused rupture and tearing of the silicon mat- erial with leaking of the button as the final result. The top surface of the H.E.M.A. contact lens showed a dense population of microorganisms with a fungi-like appearance. At dense spots ingrowth of microorganisms could be ob- served at cross-fractures. The "cornea1 side" of the lens showed spots with a heavy accumulation of degradated cells.
SURVIVAL AND GROWTH OF PHAGOCYTIZED STAPHYLOCOCCUS EPIDERMIDIS IN HUMAN MONONUCLEAR PHAGOCYTES AS DETERMINED BY ELECTRON MICROSCOPY
1-L. Eestermans, H. Bos, H.A. Verbruth*, H.v. Bronswijk** and R.H.J. Beelen
Departments of Electron Microscopy and **Internal !!edicine, Free Univer- SitiJ, Amsterdam; *Lab. for Nicrobiol- OYY, State Universitg, Utrecht
Patients treated with CAPD (contin- uous ambulant peritoneal dialysis) may suffer from frequent incidence of peri- tonitis, most often due to Staphylococ- cus epidermidis (SE). Recurrence or -
persistence of SE infections mayreflect intraleucocytic survival of bacteria that remain viable in spite of anti- microbial therapy. We studied survival
