Appendix – Useful numbers and conversions

CONTENTS

A1 Introduction A.1 Introduction

Quantitative analysis needs numbers. Many of those needed to understand and quantify eco-aspects of material production and use are presented in the Chapters of the text.

■ Table 2.1: approximate efficiency factors for energy conversion and the associated CO2 emission per useful MJ.

■ Table 6.5: the energy content of fossil fuels and the CO2 they emit when burnt.

■ Table 6.6: the energy efficiency of electricity generation and the related CO2 per useful kWhr.

■ Table 6.7: the energy and CO2 costs of alternative modes of transport.

■ Table 9.6: the energy and CO2 rating of cars as a function of mass.

■ Chapter 12: data sheets listing the attributes of 47 of the most widely used materials.

This appendix assembles further useful numbers and conversion factors.

A.2 Physical constants in SI units

Physical constant

Value in SI units

Absolute zero temperature

-273.2

°C

Acceleration due to gravity, g

9.807

m/s2

Avogadro’s number, NA

6.022 X 1023

Base of natural logarithms, e

2.718

Boltzmann’s constant, k

1.381 X 10-23

J/K

Faraday’s constant k

9.648 X 104

C/mol

Gas constant, R

8.314

J/mol/K

Physical constant

Value in SI units

Permeability of vacuum, p,0

1.257 X 10-6

H/m

Permittivity of vacuum, e0

8.854 X 10~12

F/m

Planck’s constant, h

6.626 X 10~34

J/s

Velocity of light in vacuum, c

2.998 X 108

m/s

Volume of perfect gas at STP

22.41 X 10~3

m3/mol

A.3 Conversion of units, general

Quantity

Imperial unit

SI unit

Angle, 6

1 rad

57.30°

Density, p

1 lb/ft3

16.03 kg/m3

Diffusion coefficient, D

1 cm3/s

1.0 X 10~4 m2/s

Energy, U

See Section A5

Force, F

1 kgf

9.807 N

1 lbf

4.448 N

1 dyne

1.0 X 10~5 N

Length, l

1 ft

304.8 mm

1 inch

25.40 mm

1 A

0.1 nm

Mass, M

1 tonne

1000 kg

1 short ton

908 kg

1 long ton

1107 kg

1 lb mass

0.454 kg

Power, P

See Section A5

Stress, a

See Section A4

Specific heat, Cp

1 cal/gal.°C

4.188 kJ/kg.°C

Btu/lb.°F

4.187 kg/kg.°C

Stress intensity, K1c

1 ksi Vin

1.10 MN/m3/2

Surface energy y

1 erg/cm2

1 mJ/m2

Temperature, T

1°F

0.556°K

Thermal conductivity

1 cal/s. cm.°C

418.8 W/m.°C

1 Btu/h. ft. F

1.731 W/m.°C

Volume, V

1 Imperial gall

4.546 X 10~3 m3

1 US gall

3.785 X 10~3 m3

Viscosity, n

1 poise

0.1 N. s/m2

1 lb ft. s

0.1517 N. s/m2