INTRODUCTION High-accuracy rotary encoders are required for rotational axis position measurement in ultraprecision manufacturing and measurement equipments. A typical rotary encoder is made of a glass disk with a fine grating pattern and a scanning read head unit. Digital pulse trains are output from the read head to represent the disk rotary position. The angular measurement accuracy of such a...

An overview of air-bearing spacecraft simulators is provided. Air bearings have been used for satellite attitude determination and control hardware veriŽ cation and software development for nearly 45 years. It is interesting to consider the history of this technology: how early systems were Ž rst devised and what diverse capabilities current systems provide. First a survey is given of planar sy...

Air-film damping, which dominates over other losses, plays a significant role in the dynamic response of many micro-fabricated devices with a movable mass suspended by various bearing mechanisms. Modeling the damping characteristics accurately will be greatly helpful to the bearing design, control, and test in various micromotor devices. This paper presents the simulated and experimental squeez...

BACKGROUND Creating a socket with proper fit is an important factor to ensure the comfort and control of prosthetic devices. Several techniques are commonly used to cast transtibial stumps but their effect on stump shape deformation is not well understood. This study compares the dimensions, circumferences and volumes of the positive casts and also the socket comfort between two casting methods...

One mode of transmission for C. difficile, as well as other pathogens, which has received little attention is the potential air contamination by pathogen-bearing droplets emanating from toilets. So far, modern mitigation strategies focused on cleaning hospital surfaces with products such as bleach, ignoring air contamination. Though toilets have been in use for over a century, little is known a...