Search Results

Plastics have an important niche in glazing applications where there is concern over vandalism and breakage, maintenance and repair, weight and design, and rolled up costs over the life of the article. Glazing undergoes attack by impinging solids, liquids, gases and radiation. Tests are presented which are useful in evaluating resistance of plastics to attack, both initially and after weathering. The development history of a new resistant coating for poly(methyl methacrylate) is sketched, and complete performance data are included. Coated acrylic offers an unusually good balance of properties for transportation and architectural uses.

The outstanding dry friction characteristics of Teflon TFE can be imparted to a variety of filled and reinforced compositions, many of which offer superior unlubricated wear performance. A logical extension is the application of filled TFE as marginally lubricated or thin film lubricated bearings. Under conditions of very thin film lubrication, some filled compositions of Teflon outperform conventional materials, such as babbitt and bronze. Guidelines for using filled compositions of Teflon with water lubrication are explored. Comparative test results are examined in light of theoretical relationships between thin film lubricated friction and wear performance.

THIS paper describes the background, operation, and results of a series of 50,000-milelow-duty service tests on motor oils. Comparisons of engine cleanliness and wear are presented in oils ranging from base oil to Series 2 level, using several different additive types, and a common base oil. Large differences were found in the ability of additive types and concentrations to combat harmful low-temperature engine sludge. Some observations are made on the correlation between full-scale laboratory engine tests and results of this field test.

USE of a motored engine as a convenient method for studying precombution reactions is described in this paper. Preliminary investigations of this technique were made in 1950, and this paper covers the work accomplished since then in establishing a better understanding of chemical reactions preceding knock. Extent and type of precombustion reactions which occur in the unburned charge ahead of the flame front determine the tendency of a fuel-air mixture to knock. Use of a motored engine substitutes compression of the unburned charge by the piston for compression of the end gas by the flame front. The buildup of knock-producing materials is considered in studies of mixture compositions and time factors. Observed precombustion reactions are related to problems concerning the adaptation of fuels to engines.