The Composition of Surface Layers Formed in a Lubricated Cam/Tappet ContactThe frictional behavior of two oils was measured in a cam/tappet friction apparatus using a direct acting bucket tappet geometry. One oil contained a soluble molybdenum friction modifier. The tappet was equipped with a removable friction disk, which allowed the frictional surface to be easily removed for surface characterization using surface profilometry, reflection infrared and XPS spectroscopies. The films consisted of varying amounts of inorganic phosphates, sulfates and sulfides with zinc, magnesium, and possibly molybdenum as cations. MoS 2 , expected because additives containing molybdenum and sulfur were present, was not detected. The detection limit was less than 0.1 atom percent Mo. The film formed by the friction modified oil was thinner, smoother and contained small amounts of molybdenum. While the smooth surface finish could reduce friction by improving microelastohydrodynamic lubrication, friction reduction could not be tied to any of the chemical structures detected in these experiments. . Paper No. 90-Trib-17. Associate Editor: B. Bhushan. Experimental2.1 Test Apparatus. The cam/tappet friction apparatus is an improved version of equipment described previously (Willermet, Pieprzak and Dailey, 1989;. A cam/tappet module is driven by a variable speed 2 hp. DC motor with an attached flywheel. The torque required to rotate the cam shaft is measured with a torque meter positioned between the cam shaft and flywheel (Fig. 1). Torque Meter Attachment and Mounting.Solid split shell couplings are used to attach the torque meter. These solid couplings have much lower rotational inertia than flexible couplings. This reduction in inertia significantly increases the natural frequency of the system and reduces the amplitude of the natural frequency "noise." To make the use of solid couplings possible, a visco-elastic mount was incorporated to support and stabilize the torque sensor. Cam/Tappet Module.The cam/tappet module is essentially a temperature controlled aluminum box which can accommodate a variety of value train designs (Figs. 2 and 3). The drop-in components, which establish the test configuration, are located within ±0.05 mm via locating holes. The temperature of the module is controlled by circulating a

We show that nearly all of the infrared absorption associated with sp2 coordination in diamond-like carbon deposited from benzene plasma is due to pendant (mono-substituted) benzene. Because these pendant groups have little effect on the optical and mechanical properties of the film, which are determined by the connected covalent network to which they attach, they obscure the connection between those properties and the sp3 /sp2 bonding ratio in diamond-like carbon.

High-sensitivity mercury-cadmium-teluride (MCT) detectors have generally been used in low-light experiments and where quantitation was not essential. These restrictions were commonly believed to be associated with the nonlinear response of the detectors due to intrinsic limitations of the detection process. Recent preamplifier and bias circuit designs have made significant gains in reducing and, in the case of the broadband MCTs, virtually eliminating the nonlinear character of these detectors in typical FT-IR applications. This improvement in performance in achieved through a change in detector biasing from constant current to constant voltage.

The infrared spectra from 4000 to 30 cm™1 of oriented single crystals of benzil, [C6H5CO]2, in phase I have been recorded at temperatures of 300 and 100 K along with the infrared spectra (4000 to 80 cm™1) of benzil dissolved in CC14, CH2C12, or benzene. The infrared spectrum of powdered benzil dispersed in KBr has also been recorded. The Raman spectra of single crystals have been recorded for the zz, xy, and zy components as well as for solutions in CC14 and CH2C12. The infrared and Raman spectra of the solid have been interpreted in detail on the basis of D* (P3,21) crystal symmetry with three molecules per unit cell. Proposed assignments are given for the internal fundamentals based on group frequencies for the phenyl moiety along with the polarization data for the single crystal. Additionally, the depolarization data from the Raman spectra of the solutions have also been utilized. The results are compared to the corresponding data for some similar molecules.

Emanuel, N. M. "Modelling of Oxidation Processes". Akad. Kiado (Budapest) 1986, 1. Farkas, A.; Passaglia, E. "The Decomposition of Cyclohexyl Hydroperoxide and the Peroxide-catalyzed Polymerization of Styrene".