No abstract

No abstract

THE electrometric methods that have been developed for determining lead are not of practical value. Several adaptations have been made of the thermionic electron tube to this and other titrations (1, 3, 4). The devices discussed in this article were designed to increase the speed and accuracy with which potentiometric titrations might be made. An ideal potentiometric titration apparatus should indicate the equivalence point-i. e., where AE/ A V becomes a maximum-without the necessity of constructing a curve.

Stibine was detected in the gases evolved from lead storage batteries. A new method of analysis for the quantitative estimation of stibine was developed. It is an iodo-starch colorimetric method. The quantity of SbH3 generated varies with the age and history of the battery. There is a very abrupt increase in the evolution of SbH 3 upon the completion of charge of the battery. SbH 3 formation is coincident with hydrogen evolution and the presence of metallic Sb is an essential factor. In the battery, metallic antimony is a component of the negative grid (cathode during charging) ; furthermore, metallic Sb is electrodeposited on the surface of this cathode during charging and also deposited by electrochemical displacement when the battery is idle, antimony being more noble than lead in an acid sulfate solution. Direct tests show that the concentration of stibine in the atmosphere of battery rooms does not constitute a health hazard. INTRODUCTION.

Monitors are a complex combination of analog circuits that perform absolutely amazing feats of current and voltage control at both low and high frequency. Digital circuits can reduce the complexity of interfacing with the adjustments and even be used to build complex waveforms, but they cannot replace the point at which pure power is required. Five main topic areas are covered, each building on the other in how they relate to display performance. They are glass composition, resolution and addressability, phosphor selection and aging characteristics, light output and uniformity, and the tools available to assess display performance.