Units and Conversion Tables

Section 2 combines the former separate section on Mathematics with the material involving General Information and Conversion Tables. The fundamental physical constants reflect values recommended in 1986. Physical and chemical symbols and definitions have undergone extensive revision and expansion. Presented in 14 categories, the entries follow recommendations published in 1988 by the lUPAC. The table of abbreviations and standard letter symbols provides, in a sense, an alphabetical index to the foregoing tables. The table of conversion factors has been modified in view of recent data and inclusion of SI units cross-entries for archaic or unusual entries have been curtailed. 

Pressure is defined as force per unit of area. The International System of Units (SI) pressure unit is the pascal (Pa), defined as 1.0 N /m. Conversion factors from non-SI units to pascal are given in Table 1 (see also Units and conversion factors front matter). An asterisk after the sixth decimal place indicates that the conversion factor is exact and all subsequent digits are 2ero. Relationships that are not followed by an asterisk are either the results of physical measurements or are only approximate. The factors are written as numbers greater than 1 and less than 10, with 6 or fewer decimal places (1). 

The International System of Units (SI) and Conversion Tables Quantity Unit SI Symbol... 

The book is completed with Annexes on the analysis of reactive mixtures by residue curve maps, design of heat exchangers, selection of construction materials, steam tables, vapor pressure of typical chemical components and conversion table for the common physical units. 

Table 2. Some units and conversion factors in nonlinear optics.

Measurement of energy is the most important issue from the viewpoints of efficiency and cost. To measure the energy, heating value, of a fuel, a certain amount of consumed fuel and certain amount of converted heat data are utilized. Following are units and conversion factors that are commonly used (Tables 2.1 and 2.2). 

Historically, the aim of radiation measurements was mainly to protect the hiunan body from hazardous radiation. The system of units was therefore adjusted to give the doses absorbed by human tissue. In addition, the conventional system of units was in general different from the now-accepted Standard International (SI) Units. This situation is confusing since many authors continue to use conventional units. A conversion table for the various units can be found in Handbooks, for example in the Handbook of Chemistry and Physics, 1st Student Edition, 1987, CRC Press, Boca Raton, Florida, p. F208. The table presents quantity names, symbols, expressions and special names for both the SI and the conventional systems. It also gives the values of the conventional units in SI units. The data given in the Table should help to overcome the difficulties arising from the use of the various unit systems. 

From Bolz, R.E. and Tuve, G.L., Units and conversion factors, in CRC Handbook of Tables for Applied Engineering Science, CRC Press, Boca Raton, FL, 1973, pp. 803-804. 

For several other important quantities, SI units and conversion factors are listed in Table 1 below. 

It is convenient to define a system of units that is more natural for working with atoms and molecules. The commonly accepted system of atomic units for some important quantities is summarized in Table 4-1. [Note the symbol h ( h-cross or h-bar ) is often used in place of hlln.] Additional data on values of physical quantities, units, and conversion factors can be found in Appendix 10. 

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