Design of an integral computer-based wheelchair controller/linear synchronous motor system.

The purpose of this paper is to illustrate the advantages of designing computer-based motor controllers together with innovative motors, such that maximum controller/motor system benefits are obtained. Specifically, this paper describes how a computer-based controller/drive system for powered wheelchairs has been designed and is being built and tested. This type of integral controller/drive system has been possible to build into a wheelchair only with the advent of the microprocessor-based feedback motor controller. The type of motor chosen for this project was a linear synchronous motor (LSM), which is highly efficient (90%+) and could easily be made an integral part of a wheelchair wheel, providing a "no-moving-parts" drive system. However, an LSM cannot be variable-speed-controlled without knowledge of, and controlled adjustment to, the absolute rotor versus stator position at each point in time. Microprocessor-based feedback motor controllers make precise, efficient control of LSMs possible at a reasonable cost. In addition, this combination of controller and motor provides a very flexible wheelchair control/drive system that may be easily programmed to suit the needs and necessities of the wide variety of over 200,000 persons now using powered wheelchairs.

Human factors design of a video monitor emulator and display (VMED) for visually impaired computer users.

This paper describes research conducted by the Atlanta VA Medical Center in the area of visual impairment and computer usage--in particular, work on the design of a device that reformats computer video output for use by persons with limited usable vision. The objective of the current project is to design, build, and test a video/video control interface that can be connected to and will reformat the video data of any general-purpose computer/word processor. The objectives of this work are to complete a human factors analysis of types of tasks performed on computers/word processors, and to design and build a universal interface that implements the results of the aforementioned study.

Glucose-6-phosphatase in tubular endoplasmic reticulum of hepatocytes.

The histochemical localization of glucose-6-phosphatase activity in neonatal mouse liver was studied under electron microscopy. The activity was demonstrated in the tubular endoplasmic reticulum, which pervades the glycogen areas of the cell during glycogenolysis. Activity was also demonstrated in the nuclear envelope and ergastoplasm.