Climate control through ionization

This paper summarizes some of the experimental evidence of the apparent biological effects produced by atmospheric ionization. Thermionic ion sources are discussed and the results of experimental determinations of their characteristics are presented.     

Secondary electron emission from oxide-coated cathodes

The secondary electron emission from alkaline-earth oxide-coated cathodes has been investigated under both continuous and pulsed bombardment. Various factors affecting the yield, such as dependence upon primary voltage, collecting voltage, temperature, time, and angle of incidence, are noted, and the present state of the theory is discussed.Experiments have been performed with three types of apparatus. Yield vs. Energy data reveal values of δ of 4–7 at room temperature, with a more or less flat maximum at approximately 1,000 volts primary energy.The yield increases with temperature in an exponential manner, and plots of log Δδ (i.e. δ_K° ? δ_300°K) vs. 1/T give straight lines. Values of Q₁ between 0.9 – 1.5 eV. are generally indicated, and from extrapolation of these curves, yields exceeding 100 at 850° C. are deduced. The secondary emission depends upon the degree of activation, and increases with enhancement of the thermionic emission characteristics. Short-time effects such as growth or decay of secondary current after the onset of primary bombardment or persistence after the cessation of bombardment have not been observed, and values of yield obtained by pulsed methods are in accord with those obtained under D.C. conditions. Tail phenomena reported by J. B. Johnson and interpreted as “enhanced thermionic emission” from oxidecoated cathodes become manifest only under experimental conditions characterized by certain space-charge effects, and have been effectively simulated by bombarding a tantalum target adjacent to an electron-emitting tungsten filament. Various measurements of the energy distribution of secondary electrons as a function of primary voltage and temperature have been obtained. It was observed that the average energy of the secondary electrons decreases with temperature at a rate which more than compensates for the increase in the number of secondaries emitted per incident primary. The mechanism of the observed dependence of yield upon temperature is not well understood. Various alternative explanations are discussed and, in the light of the present state of our knowledge, regarded as untenable.     

Effects of race and social class on preschool performance on the developmental test of visual-motor integration

The visual-motor integration of preschool children who varied in terms of race, sex, and socioeconomic status was assessed using the Beery-Buktenica Test of Visual-Motor Integration (VMI). An analysis of covariance revealed that there were significant main effects for race, sex, and socioeconomic status. Since, at the three- and four-year level, the VMI was normed only on white suburban children, the results of this study seemed to indicate the need for norms for black children at the preschool level. Thus, the second part of this paper reports normative data for black preschool children on the VMI.     

The dimensions of reading attitude for children in the intermediate grades

This study represents the first phase of an ongoing research program aimed at identifying the dimensions of reading attitude and determining how these dimensions relate to a broader range of variables such as reading achievement, scholastic aptitude, classroom behavior, and cognitive styles. The 150 items which comprise the experimental edition of A Survey of Reading Altitudes (Wallbrown, Brown, & Engin, 1974) were factor analyzed along with measures of scholastic aptitude, reading vocabulary, and reading comprehension. The analysis was based on the responses of 853 intermediate grade students. The attitude items were presented orally to control for reading problems, but the students also had booklets so they could read the items to themselves. Seven independent dimensions of reading attitude and one reading achievement factor were identified, interpreted, and discussed. The findings are encouraging, since they suggest that investigating the expressed reading attitudes of intermediate grade children constitutes a promising line of educational research.