Materials selection for wear resistance

The selection of materials for components exposed to wear situations involves a diversity of factors; a systematic approach to selection is out-lined to ensure that no significant factors are overlooked. The relation between materials properties and wear is examined and materials to avoid wear are considered; ancillary factors that influence selection are reviewed.     

Discrete-time fixed-lag smoothing algorithms

Kalman filtering results are applied to yield alternative computationally stable fixed-lag smoothing algorithms including reduced order and minimal order fixed-lag smoothers. The reduced order smoothing algorithms are new and clearly have advantages over the more familiar algorithms. The properties of such fixed-lag smoothers are also studied.     

Static DC to sinusoidal AC inverter using techniques of high-frequency pulse-width modulation

A dc to sinusoidal ac inverter is described in which high-frequency pulse-width modulation is used to provide a low-frequency sine-wave output without the need for either a low-frequency power transformer or for low-frequency filter components. The inverter is physically simple and has low weight and small size. From a practical viewpoint the usefulness of this inverter is further enhanced by its self-regulating property. An analysis of this circuit and its output waveform is also given which provides the mathematical basis for the experimentally observed test results. In addition to the proof of the self-regulating property, it is further proven analytically that the amplitudes of the harmonics of the sinusoidal output voltage are very small with respect to the amplitude of the fundamental voltage.     

Radio communication in the sea

Because of the electromagnetic properties of seawater, very-low-frequency communication systems are used, Surface-to-submarine, submarine-to-surface, and submarine-to-submarine propagation, as well as antennas and noise, are considered. It is shown that seawater is a good conductor and that atmospheric noise is generally more of a problem in sea communications than thermal noise. Communication ranges are limited by the effects of depth attenuation and atmospheric noise. Ranges in the tens of kilometers are possible for antennas within 5 meters of the surface; bandwidth must be less than 1 Hz and tens of kilowatts of power are required.     

Surface wave studies of hydrogen damage incubation time

Surface damage during galvanostatic H charging has been followed by monitoringin situ the change in attenuation of ultrasonic Rayleigh surface waves on charged Fe- and Ni-base fcc stainless alloys. Attenuation initially decreases as H atoms enter the surface and pin dislocations. It then passes through a minimum as significant surface damage begins to occur. The time to reach the minimum is a good estimate of damage incubation timet _c . The incubation time decreases as charging current density increases, but it is fairly insensitive to alloy composition and thermomechanical state. In contrast, the nature of the surface damage, ranging from intergranular cracking, to fissuring, to blistering, is a strong function of composition and treatment. Studies of the change in imposed cathodic potential with time at a given galvanostatic charging condition indicate that the potential also passes through a minimum att _c , but that this minimum is broad and not as sensitive a gage of failure as attenuation change. The increase in potential as the minimum is passed is associated with the exposure of failed anodic regions to the electrolyte. ANDRZEJ ZIELINSKI, formerly a Senior Postdoctoral Fellow, Department of Metallurgical Engineering and Materials Science at Notre Dame NICHOLAS F. FIORE, formerly Professor and Chairman, Department of Metallurgical Engineering and Materials Science, University of Notre Dame, Notre Dame, IN 46556     

Effects of supervisors' sex and level of authoritarianism on evaluation and reinforcement of blind and sighted workers.

Describes an experiment with 60 male and 60 female undergraduates selected on the basis of their scores on the Forced-Choice F scale (N. Berkowitz and G. Wolkon, 1964). Use of a factorial design, with authoritarianism and sex of Ss and vision of workers as the factors, revealed that blind workers were rewarded significantly more than sighted workers for identical performance and that no significant main effects occurred for level of authoritarianism and sex. No significant 2- or 3-way interactions were found. Although sex and level of authoritarianism affected attitudes toward the blind, they did not appear to affect reinforcement behavior. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Statement on mental illness and mental retardation.

The statement made on behalf of the American Psychological Association is in support of Senate Bills 755 and 756 developed by Congress in response to President Kennedy's message on mental illness and mental retardation. "The psychologist is vitually concerned with the problems of mental disorders and of mental retardation. He is especially interested in research, and in the provision of services to people through the organized agencies of society, such as the public schools, community mental health centers, hospitals, institutions for the retarded, and rehabilitation agencies of many kinds." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mood, attention, and altruism: A search for mediating variables.

Elementary schoolchildren were given a mood induction, followed by measures of generosity and incidental attention. As in a previous study, there was a linear increase in generosity from sad to control to happy conditions. Attention did not appear to mediate the mood–generosity relation. There was a curvilinear relation between age and generosity, with younger children being more generous than expected from previous findings of a linear relation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)