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A new analytical method, absorption of tunable diode laser radiation, can detect small concentrations of gases with fast response. This technique has been applied to the detection of vehicle sulfate emissions in the form of sulfuric acid (H2SO4) vapor. Previously available methods for sulfate analysis required collecting samples for 10 min. or more. Our laser system has a response time of 2.4 s. This allowed tracking the sulfate emissions of a vehicle during a Highway Fuel Economy Test. The data suggests that catalyst temperature is the major parameter controlling sulfate emissions and that storage and release of sulfur occurs at low and high catalyst temperatures, respectively. The same method detected methane during both the Highway Fuel Economy Test and the Federal Test Procedure. It identified the conditions, and corresponding concentrations, for high methane emissions. A qualitative comparison with total hydrocarbon emissions uncovered significant differences during accelerations.

There are currently two accepted criteria for assessment act exposures. Our studies have shown an interaction between the deformation velocity and level of compression during impact, resulting in a greater compression tolerance for low-speed impact than for high-speed loadings. High-speed thoracic impact can cause critical or fatal injury in physiologic experiments before exceeding the acceleration or compression tolerance. The velocity-sensitive tolerance is represented by the maximum product of velocity of deformation and compression, which is derivable from the chest compression response. As the magnitude of this “viscous” response increases, the risk of serious or fatal injury increases. This paper discusses the analysis of available literature and results from our laboratory and demonstrates the need for a viscous tolerance criterion to assess chest impact protection in high-velocity impact.

The state of California has adopted a “real-time” evaporative emission procedure that will be used starting with the 1995 model year. This test, which focuses on high temperature conditions, and measures all sources of evaporative emissions, represents a very stringent requirement. Non-fuel background emissions, i.e., paint, adhesives, and even air conditioning refrigerant, can be a significant fraction of the total measured emissions. California has included a provision in their regulations that allows for the subtraction of background emissions, using a methodology to be developed in the future. This paper reviews the history of non-fuel emission regulations, provides data showing the magnitude of the problem using the new real-time procedure, and suggests a methodology for establishing a new background emission test procedure.

A new aluminum alloy bearing material containing lead-base babbitt is described. This material provides the performance advantages of an overplated babbitt construction without requiring the plating procedure. Performance characteristics including fatigue, wear, score, and corrosion resistances and embedability are compared to standard SAE bearing materials on the basis of laboratory tests. Extensive engine dynamometer and vehicle field tests are described to show the excellent durability of this new material.

In order to understand better the head injury mechanism and to clarify the unsettled question as to whether the shear strain or the reduced pressure is the primary injury etiology during a given impact, a realistic model capable of predicting both the shear strain and the reduced pressure effects should be devised. The approach to such a realistic but complicated boundary value problem in biomechanics is achieved through the application of the finite element method. By use of the finite element displacement formulation, the human head is modeled as a viscoelastic core bonded to a thin viscoelastic shell, which simulates the brain and the skull, respectively. For purpose of comparison, two configurations-a spherical shape and a prolate ellipsoid-have been used to describe the geometry of the human head.

Previous studies of human thoracic injury tolerance and mechanical response to blunt, midsternal, anteroposterior impact loading were reported by the authors at the 1970 SAE International Automobile Safety Conference and at the Fifteenth Stapp Car Crash Conference. The present paper documents additional studies from this continuing research program and provides an expansion and refinement of the data base established by the earlier work. Twenty-three additional unembalmed cadavers were tested using basically the same equipment and procedures reported previously, but for which new combinations of impactor mass and velocity were used in addition to supplementing other data already presented. Specifically, the 43 lb/11 mph (19.5 kg/4.9m/s) and 51 lb/16 mph (23.1 kg/7.2 m/s) conditions were intercrossed and data obtained at 43 lb/16 mph (19.5 kg/7.2 m/s) and 51 lb/11 mph (23.1 kg/4.9 m/s).

SAE 1046 steel axle I-beam forgings produced by the direct quench method and the conventional reheat and quench method were examined. Impact and tensile specimens obtained from sections of two direct quench and one conventional reheat and quench axle I-beams were tested. These data were correlated with hardness and microstructure to determine the relationship between microstructure and properties. The microstructure of direct quenched beams is coarse grained with a martensite case and bainite core. In contrast, the microstructure of conventionally heat treated beams is fine grained with a martensite and/or bainite case and pearlite core. Tensile and impact properties indicate that direct quenching is an acceptable alternative to the conventional reheat and quench process. Fatigue testing of direct quenched beams is currently being performed.

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