ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
SI surpasses previous metric systems in coherence, simplicity, distinction between force and mass, choice of units, and uniformity of usage. Coherence eliminates conversion factors, other than powers of ten, within the system. Through simplification, only seven base units, two supplementary units, seventeen named derived units, and sixteen prefixes are needed to describe the entire system. Promotion of the newton as a unit of force and retention of the kilogram for mass clarifies the difference between the two quantities. New units are: pascal for pressure, siemens for electric conductance, and mole for amount of a substance. International agreement minimizes proliferation of specialized units or usage. Adopted conventions include spelling, abbreviations, style, and usage, as well as definitions for the units. Toleranceg, rounding of numbers, and elimination of the comma in multidigit numbers assume new significance. Conversion to SI offers a unique opportunity to reduce the number of sizes of many products. Several schemes for metric modularism have been developed for this purpose. In changing from conventional tip SI units, the key idea is “think metric” rather than use dual dimensioning.
Additional Material:
9 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760170403
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