Richard Jay Parker

Hide and Seek

Shortlisted for the CWA John Creasey Dagger award. ...forward this email to ten friends if it ends up in my inbox within a week I won’t slit the bitch’s throat Eleven women dead. One gruesome MO. When Leo Sharpe’s wife Laura disappears and the Vacation Killer claims responsibility, Leo’s life is torn apart. But there are significant differences in her case. Has Laura’s life been spared? Why? And for how long? For Leo, the clock is ticking...he needs to do everything in his power to stop the killer before it’s too late.

The thrillingly tense page-turner

Stop Me

Keep Her Safe

Follow You

Stalk Me

Erwin V. Zaretsky

Salvatore J. Grisaffe

The five-ball fatigue tester was used to study the behavior of nickel- bonded titanium carbide cermet and self-bonded silicon carbide balls under repeated stresses applied in rolling contact. Test conditions were 800 and 700 F, a contact angle of 200, and a shaft speed of 950 rpm with a mineral oil lubricant. The nickel-bonded titanium carbide - cermet balls were tested at maximum Hertz stresses from 400,000 to 550,000 psi, while the silicon carbide balls were tested at maximum Hertz stresses from 300,000 to 400,000 Psi. Failure appearance for both materials was unlike the fatigue pits found in bearing steels and a crystallized-glass ceramic. However, the pits were similar to those found in alumina balls (both hot pressed and cold pressed and sintered). A typical failure was a shallow eroded area less than 1 mil deep for the titanium carbide cermet and 3 to 5 mils for the silicon carbide. These failures evolved by progressing slowly from a very small pit to one spanning the running track width. Tests at 800 F with mineral oil lubrication over a range of stresses show that life varies inversely with stress to a power that ranges from 9.7 to 10.5 for the titanium carbide cermet and from 6.9 to 8.6 for the silicon carbide. The load capacity of the titanium carbide and silicon carbide balls was 3 and 1 percent, respectively, that of typical bearing steel balls, and 41 and 18 percent, respectively, that of hot-pressed alumina balls.

Surface Failure of Titanium Carbide Cermet and Silicon Carbide Balls in Rolling Contact at Temperatures to 2000 ̊F

David W. Reichard

Reduced-pressure Environment Effects on Rolling-element Fatigue Life with Super-refined Mineral Oil Lubricant

Steven T. Miller

An experimental apparatus was designed and constructed at the NASA Lewis Research Center to study one aspect of spinning friction based on interfacial slip over the entire ball-race contact area. The apparatus is capable of measuring spinning moments of less than 0. Ol inch-pound at maximum Hertz contact stresses to over 400 000 psi, speeds to 3500 rpm, and under varying contact configurations and conditions. From the torque measurement, a coefficient of spinning friction can be calculated. The apparatus comprises a drive assembly, a dead-weight load assembly, a spherical upper test specimen, a cylindrically grooved lower test specimen of varying conformity, a lower test specimen housing assembly incorporating a hydrostatic air-bearing assembly, and a torque-measuring system. In operation, the upper test specimen is loaded against the lower test specimen through the drive shaft assembly by the dead- weight load assembly. As the drive assembly is rotated, the upper test specimen rotates against the stationary lower test specimen actuating the torque-measuring system. Preliminary tests were conducted under varying Hertz stress to 136 000-psi maximum Hertz stress at a spinning speed of 950 rpm, with a 51 percent ball-groove conformity using a polyphenyl ether (5P4E), a highly purified naphthenic mineral oil, and a di-2-ethylhexyl sebacate (MIL-7808). It was found that the coefficient of spinning friction decreased with increasing maximum Hertz stress to an intermediate stress level and had a minimum value of 0. 122, 0. 089, and 0. 050, respectively, for the lubricants listed previously.

Apparatus for Studying Ball Spinning Friction

Richard Jay Parker

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