Special Issue on Manufacturing Metrology

Metrology is the science of measurement and can be divided into three overlapping activities: (1) the definition of units of measurement, (2) the realization of units of measurement, and (3) the traceability of measurement units [...]

Complexity in an unexpected place: Quantities in selected acquisition reports

In this article, the authors have looked at the definition of units in numerous acquisition programs and discovered that the units reported are almost never simple; in some programs, no two units are the same; and almost invariably, the units produced at the end of a long production run are substantially different from the early ones. They have identified three reasons why the units may differ. The first reason is changes over time, generally as system capabilities are improved. The second is due to mixed types, where units that are inherently dissimilar—such as CH-47F and MH-47G helicopters—are produced by the same program and each is called one unit. The final reason why units can differ is reporting accidents. The authors give examples of all three and discuss possible methods of improving the reporting requirement.

A New State Time and Frequency Standard of the USSR

In 1976 a new state primary time and frequency standard of the USSR was certified and confirmed with an error of reproducibility less than 1 × 10−13 and with an unavoidable systematic error less than 3–4 × 10−13. This standard includes a laboratory primary cesium beam frequency standard providing an independent definition of units in the SI system, primary hydrogen frequency standards preserving the units of frequency and time intervals, and hydrogen and cesium clocks providing the TA(SU) and UTC(SU) time scales.