Interfacing the aluminium-air battery with telecommunications equipment
The tests carried out by British Telecom (BT) on the aluminum-air battery with regard to using the battery in a standby power system are described. The background to BT's interest in the aluminium-air battery is outlined along with the design considerations of a prototype power system to be installed in the switching network. The need for an interfacing DC/DC converter between the battery and the equipment is described, and the converter's novel features and operation are explained.<<ETX>>
Extending the reliability of DC power in a telecommunications network
To maintain continuity of service of any telecommunications network it is necessary to provide some form of back-up power to cater for uncertainty of the public utility supply. The growing use of smaller and more remote sites associated with cellular networks and optical fibre networks really demands a compact dependable source of DC power, with minimal maintenance costs, capable of extending the back-up cover afforded by small battery installations. Engine alternator sets particularly when infrequently used and lightly loaded, often do not provide the desired level of reliability. One option that has been developed to meet this need is the aluminium-air fuel cell. Applications ranging from a few hundred watts supply required for cellular transceiver stations to a study for a 20 kW system for a major network operation are described.<<ETX>>
Role of the coronoid process in varus osteoarticular stability of the elbow.
The role of the coronoid process in varus osteoarticular stability of the elbow was investigated in 10 cadaveric elbows. Testing was performed at multiple flexion angles after incremental removal of the coronoid. At each flexion angle, removal of more than 50% of the coronoid produced a statistically significant decrease in the load resisting varus displacement compared with all lesser resection levels (P < .003). There was a trend for decreasing load after removal of 50% of the coronoid. The mean decrease in load across all flexion angles was 10.1%, 50.4%, and 75.4% after removal of 50%, 75%, and 100% of the coronoid, respectively. Resistance to varus displacement tended to decrease more as a percent of control at lower flexion angles than at higher flexion angles after removal of more than 50% of the coronoid. The coronoid process was found to be a key varus stabilizer in the elbow and may contribute more to elbow stability in extension than in flexion.