fiber/matrix interaction effects on fracture toughness of structural composites

the object of the study was to relate the effects of fiber, matrix and interface to the fracture toughness of fiber reinforced plastic composites. the initial part of the study employed a model composite system to determine the resistance to crack propagation normal to the fibers. laminates suitable for projectile impact tests were also u..

studies on eel cholinesterase for use in detection devices

electric eel acche solutions and enzyme-impregnated glass fiber tickets need excess protein, and suitable buffer for thermal stability. quaternary ammonium compounds were tested as stability enhancers. optimum conditions for enzyme on tickets or in solution below 40 c were found. triton x-100 was found a suitable wetting agent for tickets..

erosion resistant ar coatings for ir windows

feasibility of rain erosion resistance of two layer ar coatings on zns small sample windows with good surface finish has been demonstrated. when exposed to 1 inch/hour simulated rainfalls for 20 minutes at a relative drop impact velocity of 470 mph, transmission losses of about 10 percent occurred. (author)

future of precision machining of optics: a turn for the better

the objectives of this briefing are to review results of diamond turning optical fabrication and to discuss future applications and promising research ideas, with an emphasis towards high power laser systems. design flexibility is afforded by diamond turning as well exemplified by the compound axicons and torics which are discussed (era c..

serologic test development. progress report, july 1, 1975--june 30, 1976

the indirect enzyme-labeled antibody (ela) hog cholera test has been successfully tested on a 640-sample, computer-coded serum tank. a greater than 99 percent correlation with the hog cholera serum neutralization test was observed. a successful field trial of the ela hog cholera test was carried out. the serum factor present in packinghou..

soft abrasive disc

a soft abrasive tool is disclosed as comprising a solid molded mixture of predetermined quantities of an aluminum wool material and a catalyst setting elastomeric polyurethane binder material, the unique combination of which has been mixed, molded under pressure, and cured at room temperature in such manner as to have a disc-like, cup-lik..

fabrication and characterization of grafted hydrogel coatings prepared by active-hydrogen techniques for heart-assist devices

coatings of hydrogels of polyacrylamide have been prepared on substrata of polyetherurethane and polypropylene. the graft polymerizations were initiated with atomic hydrogen, which forms free radicals in the underlayers and in the polymerizate to form covalently grafted hydrogel coatings. by mapping the x-ray fluorescence of ionic silver ..

sprayable low density ablator

a sprayable, low density ablative composition is described. the composition consists of: (1) 100 parts by weight of a mixture of 25-65 by weight of phenolic microballoons, 0-20 by weight of glass microballoons, 4-10 by weight of glass fibers, 25-45 by weight of an epoxy-modified polyurethane resin, 2-4 by weight of a benetonite dispersing..

hydrogel-graft-coated plastic parts for hemodialysis

by means of active-vapor chemical grafting, hydrophilic polymer coatings were applied to surfaces of segmented polyetherurethanes these modified surfaces are shown to be non-thrombogenic when implanted in canine aortas or venae cavae, in the latter test remaining patent for longer than 30 days. procedures were worked out for fabricating r..

hydrodynamic drag of disks with compliant membrane/substrate faces

a disk with interchangeable faces of compliant membrane/substrate combinations was spin-tested in a water tank. a device for stretching a membrane uniformly and with repeatable results was designed, fabricated, and successfully employed. six membrane materials and three substrate materials were utilized to fabricate over 36 different comp..