ABC's of Regulator Maintenance

A practical approach to the maintenance of electrical and electronic regulators is presented. It is possible to identify and record critical points which define regulator performance. This simplifies maintenance routines on complex networks and permits ready comparison with previously recorded data for evaluation and troubleshooting, thereby reducing training and diagnostic time. Examples of actual systems are given.     

Landslide Hazards and Their Reduction

Landslides are a widespread and costly problem in many parts of the United States. Although reliable estimates of the costs of landslide damage are difficult to obtain, a conservative estimate of the present-day direct and indirect costs of slope failures in the United States exceeds $1 billion annually.

Losses from landslides can be significantly reduced by the cooperative effort of geologists, engineers, and planners, clearly demonstrating the value of loss mitigation measures. A program to reduce the losses from landslides in the hillside areas of Los Angeles has been in effect since 1952 and, by one method of evaluation, has reduced losses by nearly a factor of 50.     

Using animation to help students learn computer algorithms

This paper compares the effects of graphical study aids and animation on the problem-solving performance of students learning computer algorithms. Prior research has found inconsistent effects of animation on learning, and we believe this is partly attributable to animations not being designed to convey key information to learners. We performed an instructional analysis of the to-be-learned algorithms and designed the teaching materials based on that analysis. Participants studied stronger or weaker text-based information about the algorithm, and then some participants additionally studied still frames or an animation. Across 2 studies, learners who studied materials based on the instructional analysis tended to outperform other participants on both near and far transfer tasks. Animation also aided performance, particularly for participants who initially read the weaker text. These results suggest that animation might be added to curricula as a way of improving learning without needing revisions of existing texts and materials. Actual or potential applications of this research include the development of animations for learning complex systems as well as guidelines for determining when animations can aid learning.     

Dissociation of demyelination and viral clearance in congenitally immunodeficient mice infected with murine coronavirus JHM

Radiolabelled vitellogenin produced by juvenile grouper following injection of 3H-leucine, 32P-orthophosphate and estradiol-stimulation was purified by anion-exchange and gel filtration chromatography and characterized by electrophoresis and chemical analysis. The radiolabelled product was found to exist in two heterogeneous molecular weight forms by electrophoresis under nondenaturing conditions on polyacrylamide gel with M(r), of 260,000 and 525,000. It showed two protein monomers (M(r) 113,000 and 140,000) on electrophoresis under denaturing condition on a sodium dodecyl sulphate-polyacrylamide gel. The purified material contained 17.2% total lipid with 1.3% cholesterol and 2.1% triglycerides, 8-21 micrograms/mg protein total carbohydrate and 6.8 micrograms phosphate/mg protein; amino acid analysis showed a profile comparable to that found for vitellogenins isolated from the grouper, medaka, goldfish and rainbow trout. The study showed grouper vitellogenin to be a glycophospholipoprotein similar in composition to vitellogenins from other teleosts and demonstrated that vitellogenins can be induced in juveniles by injection with estradiol-17 beta.     

Truss influence lines on a time sharing system

A computer program is presented for finding influence lines for plane truss member forces on a time sharing system. The program is interactive; requesting data from the user as needed. The output can consist of either printed influence line ordinales on a printing terminal or plotted influence lines on a graphic terminal.     

Modern experimental methods for the observation of the far infrared spectra of polymers

The introduction of very sensitive detectors and the use of phase modulation has enabled interferometric spectroscopy to be extended downwards in frequency until the spectral coverage overlaps that provided by microwave dielectric methods. The radiometric precision available has been steadily improved by taking advantage of both instrumental and computational advances and the accuracy which can now be attained is comparable to that of dielectric or mid-infrared methods. Both the real and the imaginary components of the complex dielectric constant (or the complex refractive index) can now be obtained for moderately transparent materials over the millimetre and submillimetre bands for a wide range of specimen temperature, and reflectance methods have been developed for the study of heavily absorbing specimens. The far infrared band is particularly appropriate for the study of high polymers. With these instrumental innovations considerable advances may be expected in the understanding of molecular motion in these materials.