SI units conversion table

Systeme International (SI) units conversion table for common laboratory tests. Ann Pharmacother 1995 29 100-7. 

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

Section 7.1 gives examples illustrating the use of quantity calculus for converting the values of physical quantities between different units. The table in section 7.2 lists a variety of non-SI units used in chemistry, with the conversion factors to the corresponding SI units. Conversion factors for energy and energy-related units (wavenumber, frequency, temperature and molar energy), and for pressure units, are also presented in tables inside the back cover. 

Table 6 presents a detailed list of conversion factors that can be used to convert between U.S.-British units and SI units, while Table 7 gives a simplified and abbreviated list of equivalences for converting unacceptable units commonly used by chemical engineers into acceptable SI units. 

For consistency with the original references, conditions in U.S. heavy-water plants have been expressed in English units. Conversion tables to SI units are given in App. B. 

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). 

TABLE 1-4 Conversion Foelors U.S. Customary and Commonly Used Units to SI Units... 

TABLE 1-5 Metric Conversion Factors as Exact Numerical Multiples of SI Units... 

Table 1-7 provides a number of useful conversion factors. To make a conversion of an element in U.S. customary units to SI units, one multiplies the value of the U.S. customary unit, found on the left side in the table, by the equivalent value on the right side. For example, to convert 10 British thermal units to joules, one multiplies 10 by 1054.4 to obtain 10544 joules. 

Units employed in diffusivity correlations commonly followed the cgs system. Similarly, correlations for mass transfer correlations used the cgs or Enghsh system. In both cases, only the most recent correlations employ SI units. Since most correlations involve other properties and physical parameters, often with mixed units, they are repeated here as originally stated. Common conversion factors are listed in Table 1-4. 

Values of measurement in the Code text will be followed by an approximate equivalent value in SI units. Tables will have a footnote for SI conversion units used in the table. 

Conversion factors to SI units from other units are given in Table 1.2 which is based on a publication by Mullin(3). 

Some approximate conversion factors to SI units are given in Table 1.1. These are worth committing to memory, to give some feel for the units for those more familiar with the traditional engineering units. The exact conversion factors are also shown in the table. A more comprehensive table of conversion factors is given in Appendix D. 

Besides the ASTM standard tests, a number of general reference books have been published on testing and on the mechanical properties of polymers and viscoelastic materials (2-7). Unfortunately, a great variety of units are used in reporting values of mechanical tests. Stresses, moduli of elasticity, and other properties are given in such units as MK.S (SI), cgs, and English units. A table of conversion factors is given in Appendix II. 

Table C. 1. Conversion factors from atomic to SI units...

Tables C. 1-C.4 provide conversion factors from a.u. to SI units and a variety of practical (thermochemical, crystallographic, spectroscopic) non-SI units in common usage. Numerical values are quoted to six-digit precision (though many are known to higher accuracy) in an abbreviated exponential notation, whereby 6.022 14(23) means 6.022 14 x 1023. In this book we follow a current tendency of the quantum chemical literature by expressing relative energies in thermochemical units (kcal mol-1), structural parameters in crystallographic Angstrom units (A), vibrational frequencies in common spectroscopic units (cm-1), and so forth. These choices, although inconsistent according to SI orthodoxy, seem better able to serve effective communication between theoreticians and experimentalists.

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