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BOTH experimental and analytical phases of the aircraft vibration problem are covered by Mr. Critchlow, who has made a thorough study of this increasingly important subject. As a result of this research work, methods of calculating coupled modes of vibration of aircraft structures have been developed that agree quite closely with measured data. An important factor in cutting down the time, labor, and expense required in making vibration and flutter studies has been the adaptation of punched card calculating machines to perform the routine calculations.

Among the most pressing needs in the development of rational approaches for vehicle handling quality evaluation is a method for relating the driver's actions with the car's performance capability. This paper describes a concept which provides a graphic and objective measurement of this relationship, including the effect of road surface conditions on overall system behavior. Based on a continuous plot of the vector acceleration of the vehicle in the horizontal plane, the resultant figure, which is called a g-g diagram, is shown to be useful for characterizing the vehicles's envelope of performance, the variation of this envelope with tire-road surface conditions, the accessibility of various operating points to the driver in performing a task, performance margins utilized by the driver in normal operation, and for several other applications.

Various methods of measuring the percentage of diluent in used crankcase-oils are summarized in this paper but the broader questions of deterioration of the oil due to other factors are not considered. The characteristics of viscometric methods and of steam, atmospheric and vacuum-distillation methods are discussed. It is pointed out that as dilution is not the only change the oil undergoes in service, methods based upon the assumption that oil is unchanged except by the presence of diluent may yield misleading results. Distillation methods seem best suited for this determination and those which are rational, in that the evaluation of the diluent is based on the change in the properties of the distillate as the distillation proceeds from diluent to oil, seem to promise the greatest accuracy over a wide range of diluents and oils.

Two biofuels were converted chemically to biodiesels: cottonseed oil, which was produced in Macedonia, Greece, and used frying oil which was collected in the city of Antwerp, Belgium. The conversion to biodiesels was accomplished in the Department of Industrial Sciences and Technology of the Karel de Grote-Hogeschool, Hoboken, Belgium. Mixtures of the two biodiesels with diesel were prepared as B10, B20, B30, B40, B50 and B100 (B10 means a 10 % by weight of biodiesel). These mixtures were used as fuel on two cars in the Combustion Laboratory in the Department of Industrial Sciences and Technology of the Karel de Grote-Hogeschool, Hoboken, Belgium. The two cars were a VOLVO V70 2.5 L turbo diesel and a FORD TRANSIT 2.5 L diesel. The cars were run under full load at 30, 50, 90 and 120 km/h speeds on a chassis dynamometer.

Very few data seem to be available on the frictional losses in automobile engines caused by the failure of the oil to perform its function as a lubricant. The researches of the Lubrication Inquiry Committee in England indicate that the friction of a flooded bearing is proportional to the speed of the engine, the area of the bearing and the viscosity of the lubricant and is independent of the pressure and of the materials of which the opposing surfaces are composed. The principal sources of friction in an engine are the crankshaft, the camshaft and the connecting-rod bearings, which rotate; the pistons and the valves, which slide; and the auxiliaries, such as the generator, the pump and the distributor.

IN the discussion of automatic devices in motor cars presented in this paper, special emphasis is placed on fully automatic and semi-automatic clutches, drives, and transmissions. Two methods of attack are being used to eliminate the clutch pedal: power operation of the mechanical clutch and the fluid coupling. Three fundamental types of control for vacuum-operated clutches are discussed: 1. Position or follow-up type valving. 2. Balanced or pressure-sensitive type. 3. Balanced cushion with variable bleed. In a review of the merits and demerits of the fluid coupling, fuel economy and the shock loads on the driving mechanism are stressed. An appraisal of the operating principles and characteristics of various fully and semi-automatic transmissions compares the following: overdrive; four-speed semi-automatic transmission with fluid coupling; three-speed fully automatic transmission; and four-speed fully automatic transmission with fluid coupling.