Engineering Companion P2 pptx

CHAPTER ONE1.18 TABLE 1.6 Conversion Factor g c for the Common Unit Systems Quantity Si English engineering* cgs‡ Metric engineering Mass kilogram, kg pound mass, lb gram, g kilogram mass, kg Length meter, m foot, ft centimeter, cm meter, m Time second, s second, s, or hour, h second, s second, s Force newton, N pound force, lb f dyne, dyn kilogram force, kg f g c 1 32.174 1 9.80665 kg ⅐ m/(N ⅐ s 2 )‡ lb ⅐ ft /(1b f ⅐ s 2 ) or 4.1698 ϫ 10 2 lb ⅐ ft /(lb f ⅐ h 2 ) g ⅐ cm /(dyn ⅐ s 2 )kg⅐ m/(kg f ⅐ s 2 ) *In this system of units the temperature is given in degrees Fahrenheit (ЊF). † Centimeter-gram-second: this system of units has been used mostly in scientific work. ‡ Since 1 kg ⅐ m/s 2 ϭ 1N,then g c ϭ 1inthe SI system of units. Source: From Rohsenow, Hartnett, and Ganic´. 2 velocity—meters per second (m/s) acceleration—meters per second squared (m /s 2 ) pressure—Newton per meter squared (N/m 2 ) The unit of pressure (N/m 2 )isoften referred to as the pascal (Pa). In the SI system, there is one unit of energy, whether the energy is thermal, mechanical, or electrical: the joule (J), (1 J ϭ 1N⅐ m). The unit for energy rate, or power, is the J/s, where one joule per second is equivalent to one watt (W) (1 J/s ϭ 1W). In the English system of units, it is necessary to relate thermal and mechanical energy via the mechanical equivalent of heat, J c . Thus J ϫ thermal energy ϭ mechanical energy c The unit of heat in the English system is the British thermal unit (Btu). When the unit of mechanical energy is the pound-force-foot (lb f ⅐ ft), then J ϭ 778.16 lb ⅐ ft /Btu c f as 1 Btu ϭ 778.16 lb f ⅐ ft. Happily, in the SI system the units of heat and work are identical and J c is unity. 6. SI Learning and Usage. The technical and scientific community throughout the world accepts SI units for use in both applied and theoretical calculation. With such widespread acceptance, every engineer must become proficient in the use of this system if he or she is to remain up to date. For this reason, most calculation procedures in this handbook are given in both SI and USCS. This will help all engineers become proficient in using both systems. However, in some cases results and tables are given in one system, mostly to save space, and conversion factors are printed at the end of such results (or tables) for the reader’s convenience. Engineers accustomed to working in USCS are often timid about using SI. There are really no sound reasons for these fears. SI is a logical, easily understood, and ENGINEERING UNITS 1.19 readily manipulated group of units. Most engineers grow to prefer SI, once they become familiar with it and overcome their fears. Overseas engineers who must work in USCS because they have a job requiring its usage will find the dual-unit presentation of calculation procedures most helpful. Knowing SI, they can easily convert to USGS. An efficient way for the USCS-conversant engineer to learn SI follows these steps: 1. List units of measurement commonly used in one’s daily work. 2. Insert, opposite each USGS unit, the usual SI unit used; Table 1.5 shows a variety of commonly used quantities and the corresponding SI units. 3. Find, from a table of conversion factors, such as Table 1.5, the value to use to convert the USGS unit to SI, and insert it in the list. (Most engineers prefer a conversion factor that can be used as a multiplier of the USGS unit to give the SI unit.) 4. Apply the conversion factor whenever the opportunity arises. Think in terms of SI when an USGS unit is encountered. 5. Recognize—here and now—that the most difficult aspect of SI is becoming comfortable with the names and magnitudes of the units. Numerical conversion is simple once a conversion table has been set up. So think pascal whenever pounds per square inch pressure are encountered, newton whenever a force in pounds is being dealt with, etc. CONVERSION FACTORS Conversion factors between SI and USGS units are given in Table 1.5. Note that E indicates an exponent, as in scientific notation, followed by a positive or negative number representing the power of 10 by which the given conversion factor is to be multiplied before use. Thus, for the square feet conversion factor, 9.290 304 ϫ 1/100 ϭ 0.092 903 04, the factor to be used to convert square feet to square meters. Forapositive exponent, as in converting British thermal units per cubic foot to kilojoules per cubic meter, 3.725 895 ϫ 10 ϭ 37.258 95. Where a conversion factor cannot be found, simply use the dimensional sub- stitution. Thus, to convert pounds per cubic inch to kilograms per cubic meter, find 1lb ϭ 0.453 592 4 kg and 1 in 3 ϭ 0.000 016 387 06 m 3 . Then, 1 lb/in 3 ϭ 0.453 592 4 kg /0.000 016 387 06 m 3 ϭ 2.767 990 E ϩ 04. SELECTED PHYSICAL CONSTANTS A list of selected physical constants is given in Table 1.7. DIMENSIONAL ANALYSIS Dimensional analysis is the mathematics of dimensions and quantities and provides procedural techniques whereby the variables that are assumed to be significant in 1.20 TABLE 1.7 Fundamental Physical Constants 1 sec. ϭ 1.00273791 sidereal seconds sec. ϭ mean solar second g 0 ϭ 9.80665 m. /sec. 2 Definition: g 0 ϭ standard gravity 1 liter ϭ 0.001 cu. m. 1 atm. ϭ 101,325 newtons/sq. m. Definition: atm. ϭ standard atmosphere 1 mm. Hg (pressure ϭ 1 ⁄ 760 ) atm. ϭ 133.3224 newtons/sq. m. mm. Hg (pressure) ϭ standard millimeter mercury 1 int. ohm ϭ 1.000495 ע 0.000015 abs. ohm int. ϭ international; abs. ϭ absolute 1 int. amp. ϭ 0.999835 ע 0.000025 abs. amp. amp. ϭ ampere 1 int. coul. ϭ 0.999835 ע 0.000025 abs. coul. coul. ϭ coulomb 1 int. volt ϭ 1.000330 ע 0.000029 abs. volt 1 int. watt ϭ 1.000165 ע 0.000052 abs. watt 1 int. joule ϭ 1.000165 ע 0.000052 abs. joule T 0 Њ C ϭ 273.150 ע 0.010 K. Absolute temperature of the ice point, 0 ЊC. R ϭ 8.31439 ע 0.00034 abs. joule/deg. mole ϭ 1.98719 ע 0.00013 cal./deg. mole ϭ 82.0567 ע 0.0034 cu. cm. atm./deg. mole ϭ 0.0820567 ע 0.0000034 liter atm. / deg. mole R ϭ gas constant per mole ln 10 ϭ 2.302585 ln ϭ natural logarithm (base e) R ln 10 ϭ 19.14460 ע 0.00078 abs. joule/deg. mole ϭ 4.57567 ע 0.00030 cal./deg. mole N ϭ (6.02283 ע 0.0022) ϫ 10 23 /mole N ϭ Avogadro number h ϭ (6.6242 ע 0.0044) ϫ 10 Ϫ 34 joule sec. h ϭ Planck constant c ϭ (2.99776 ע 0.00008) ϫ 10 8 m./sec. c ϭ velocity of light (h 2 /8 ␲ 2 k) ϭ (4.0258 ע 0.0037) ϫ 10 Ϫ 39 g. sq. cm. deg. Constant in rotational partition function of gases (h /8 ␲ 2 c) ϭ (2.7986 ע 0.0018) ϫ 10 Ϫ 39 g. cm. Constant relating wave number and moment of inertia Z ϭ Nhc ϭ 11.9600 ע 0.0036 abs. joule cm./mole ϭ 2.85851 ע 0.0009 cal. cm. / mole Z ϭ constant relating wave number and energy per mole (Z /R) ϭ (hc /k) ϭ c 2 ϭ 1.43847 ע 0.00045 cm. deg. C 2 ϭ second radiation constant F ϭ 96,501.2 ע 10.0 int. coul. /g equiv. or int. joule / int. volt g equiv, ϭ 96,485.3 ע 10.0 abs. cou. /g equiv. Or abs. joule /abs. volt g equiv. ϭ 23,068.1 ע 2.4 cal. /int. volt g equiv. ϭ 23,060.5 ע 2.4 cal. /abs. volt g equiv. F ϭ Faraday constant e ϭ (1.60199 ע 0.00060) ϫ 10 Ϫ 19 abs. coul. ϭ (1.60199 ע 0.00060) ϫ 10 Ϫ 20 abs. e.m.u. ϭ (4.80239 ע 0.00180) ϫ 10 Ϫ 10 abs. e.s.u. e ϭ electronic charge 1 int. electron-volt/molecule ϭ 96,501.2 ע 10 int. joule /mole ϭ 23,068.1 ע 2.4 cal. /mole 1.21 1 abs. electron-volt/molecule ϭ 96,485.3 ע 10.abs. joule / mole ϭ 23,060.5 ע 2.4 cal. /mole 1 int. electron-volt ϭ (1.60252 ע 0.00060) ϫ 10 Ϫ 12 erg 1 abs. electron-volt ϭ (1.60199 ע 0.00060) ϫ 10 Ϫ 12 erg hc ϭ (1.23916 ע 0.00032) ϫ 10 Ϫ 4 int. electron-volt cm. ϭ (1.23957) ע 0.00032) ϫ 10 Ϫ 4 abs. electron-volt cm. k ϭ (8.61442 ע 0.00100) ϫ 10 Ϫ 5 int. electron-volt/deg. ϭ (8.61727 ע 0.00100) ϫ 10 Ϫ 5 abs. electron-volt/deg. ϭ (R /N) ϭ (1.38048 ע 0.00050) ϫ 10 Ϫ 23 joule/deg. Constant relating wave number and energy per molecule k ϭ Boltzmann constant 1 I.T. cal. ϭ ( 1 ⁄ 860 ) ϭ 0.00116279 int. watt-hr. ϭ 4.18605 int. joule ϭ 4.18674 abs. joule ϭ 1.000654 cal. Definition of I.T. cal.: I.T. ϭ International steam tables cal. ϭ thermochemical calorie 1 cal. ϭ 4.1840 abs. joule ϭ 4.1833 int. joule ϭ 41.2929 ע 0.0020 cu. cm. atm. ϭ 0.0412929 ע 0.0000020 liter atm. Definition: cal. ϭ thermochemical calorie 1 I.T. cal. /g. ϭ 1.8 B.t.u. /lb. Definition of B.t.u.: B.t.u. ϭ I.T. British Thermal Unit 1B.t.u. ϭ 251.996 I.T. cal. ϭ 0.293018 int. watt-hr. ϭ 1054.866 int. joule ϭ 1055.040 abs. joule ϭ 252.161 cal. cal. ϭ thermochemical calorie 1 horsepower ϭ 550 ft lb. (wt.) /sec. ϭ 745.578 int. watt ϭ 745.70 abs. watt Definition of horsepower (mechanical): lb. (wt.) ϭ weight* of 1 lb. At standard gravity 1 in. ϭ (1/0.39337) ϭ 2.54 cm. 1ft ϭ 0.304800610 m. 1 lb. ϭ 453.5924277 g. 1 gal. ϭ 231 cu. in. ϭ 0.133680555 cu. ft. Ϫ 3 ϭ 3.785412 ϫ 10 cu. m. ϭ 3.785412 liter Definition of in.: in. ϭ U.S. inch ft ϭ U.S. foot (1 ft. ϭ 12 in.) Definition; lb. ϭ avoirdupois pound Definition; gal. ϭ U.S. gallon *lb (wt.) ϭ lb f Source: From Perry, Green, and Maloney. 1 CHAPTER ONE1.22 a problem can be formed into dimensionless parameters, the number of parameters being less than the number of variables. This is a great advantage, because fewer experimental runs are then required to establish a relationship between the param- eter than between the variables. While the user is not presumed to have any knowl- edge of the fundamental physical equations, the more knowledgeable the user, the better the results. If any significant variable or variables are omitted, the relationship obtained from dimensional analysis will not apply to the physical problem. On the other hand, inclusion of all possible variables will result in losing the principal advantage of dimensional analysis, i.e., the reduction of the amount of experimental data required to establish a relationship. Formal methods of dimensional analysis are given in Chap. 10. REFERENCES* 1. R. H. Perry, D. W. Green, and J. O. Maloney (eds.), Perry’s Chemical Engineers Handbook, 6th ed., McGraw-Hill, New York, 1984. 2. W. M. Rohsenow, J. P. Hartnett, and E. N. Ganic´ (eds.), Handbook of Heat Transfer Fun- damentals, 2d ed., McGraw-Hill, New York, 1985. 3. E. A. Avallone and T. Baumeister III (eds.), Mark’s Standard Handbook for Mechanical Engineers, 9th ed., McGraw-Hill, New York, 1987. 4. O. W. Eshbach and M. Souders, Handbook of Engineering Fundamentals, John Wiley & Sons, New York, 1975. 5. T. G. Hicks, Standard Handbook of Engineering Calculation, 2d ed., McGraw-Hill, New York, 1985. 6. R. H. Perry, Engineering Manual, 3d ed., McGraw-Hill, New York, 1976. 7. J. Whitaker and B. Benson, Standard Handbook of Video and Television Engineering, 3d ed., McGraw-Hill, 2000. 8. R. Walsh, McGraw-Hill Machining and Metalworking Handbook, 2d ed., McGraw-Hill, 1999. 9. D. Cristiansen, Electronics Engineer’s Handbook, 4th ed., McGraw-Hill, 1997. * Those references listed above but not cited in the text were used for comparison between different data sources, clarification, clarity of presentation, and, most important, reader’s convenience when further interest in the subject exists. 2.1 CHAPTER 2 GENERAL PROPERTIES OF MATERIALS All materials have properties which must be known in order to promote their proper use. Knowing these properties is also essential to selecting the best material for a given application. This chapter includes general properties widely used in the field of chemical, mechanical, civil, and electrical engineering. Note that results are given in SI units. Use Table 1.5 of Chap. 1 to obtain results in USGS units. CHEMICAL PROPERTIES Every elementary substance is made up of atoms which are all alike and which cannot be further subdivided or broken up by chemical processes. There are as many different classes or families of atoms as there are chemical elements (Table 2.1). Twoormore atoms, either of the same kind or of different kinds, are, in the case of most elements, capable of uniting with one another to form a higher order of distinct particles called molecules. If the molecules or atoms of which any given material is composed are all exactly alike, the material is a pure substance. If they are not all alike, the material is a mixture. If the atoms which compose the molecules of any pure substances are all of the same kind, the substance is, as already stated, an elementary substance. If thc atoms which compose the molecules of a pure chemical substance are not all of the same kind, thc substance is a compound substance. It appears that some substances which cannot by any available means be decom- posed into simpler substances and which must, therefore, be defined as elements, are continually undergoing spontaneous changes or radioactive transformation into other substances which can be recognized as physically different from the original substance. The view generally accepted at present is that the atoms of all the chem- ical elements, including those not known to be radioactive, consist of several kinds of still smaller particles, three of which are known as protons, neutrons, and elec- trons. The protons are bound together in the atomic nucleus with other particles, including neutrons, and are positively charged. The neutrons are particles having approximately the mass of a proton but no charge. The electrons are negatively charged particles, all alike, external to the nucleus; and sufficient in number to neutralize the nuclear charge in an atom. The differences between the atoms of Copyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. CHAPTER TWO2.2 TABLE 2.1 Chemical Elements a Element Symbol Atomic No. Atomic weight b Actinium Ac 89 Aluminum Al 13 26.9815 Americium Am 95 Antimony Sb 51 121.75 Argon c Ar 18 39.948 Arsenic d As 33 74.9216 Astatine At 85 Barium Ba 56 137.34 Berkelium Bk 97 Beryllium Be 4 9.0122 Bismuth Bi 83 208.980 Boron d B510.811 l Bromine e Br 35 79.904 m Cadmium Cd 48 112.40 Calcium Ca 20 40.08 Californium Cf 98 Carbon d C612.01115 l Cerium Ce 58 140.12 Cesium k Ca 55 132.905 Chlorine f Cl 17 35.453 m Chromium Cr 24 51.996 m Cobalt Co 27 58.9332 Columbium (see Niobium) Copper Cu 29 63.546 m Curium Cm 96 Dysprosium Dy 66 162.50 Einsteinium Es 99 Erbium Er 68 167.26 Europium Eu 63 151.96 Fermium Fm 100 Fluorine g F918.9984 Francium Fr 87 Gadolinium Gd 64 157.25 Gallium k Ga 31 69.72 Germanium Ge 32 72.59 Gold Au 79 196.967 Hafnium Hf 72 178.49 Helium c He 2 4.0026 Holmium Ho 67 164.930 Hydrogen h H11.00797 l Indium In 49 114.82 Iodine d I53126.9044 Iridium Ir 77 192.2 Iron Fe 26 55.847 m Krypton c Kr 36 83.80 Lanthanum La 57 138.91 Lead Pb 82 207.19 Lithium i Li 3 6.939 Lutetium Lu 71 174.97 Magnesium Mg 12 24.312 GENERAL PROPERTIES OF MATERIALS 2.3 TABLE 2.1 Chemical Elements (Continued ) Element Symbol Atomic No. Atomic weight b Manganese Mn 25 54.9380 Mendelevium Md 101 Mercury e Hg 80 200.59 Molybdenum Mo 42 95.94 Neodymium Nd 60 144.24 Neon c Ne 10 20.183 Neptunium Np 93 Nickel Ni 28 58.71 Niobium Nb 41 92.906 Nitrogen f N714.0067 Nobelium No 102 Osmium Os 76 190.2 Oxygen f O815.9994 l Palladium Pd 46 106.4 Phosphorus d P1530.9738 Platinum Pt 78 195.09 Plutonium Pu 94 Polonium Po 84 Potassium K 19 39.102 Praseodymium Pr 59 140.907 Promethium Pm 61 Protactinium Pa 91 Radium Ra 88 Radon i Rn 86 Rhenium Re 75 186.2 Rhodium Rh 45 102.905 Rubidium Rb 37 85.47 Ruthenium Ru 44 101.07 Samarium Sm 62 150.35 Scandium Sc 21 44.956 Selenium d Se 34 78.96 Silicon d Si 14 28.086 l Silver Ag 47 107.868 m Sodium Na 11 22.9898 Strontium Sr 38 87.62 Sulphur d S1632.064 l Tantalum Ta 73 180.948 Technetium Tc 43 Tellurium d Te 52 127.60 Terbium Tb 65 158.924 Thallium Tl 81 204.37 Thorium Th 90 232.038 Thulium Tm 69 168.934 TinSn50118.69 Titanium Ti 22 47.90 Tungsten W 74 183.85 Uranium U 92 238.03 Vanadium V 23 50.942 Xenon c Xe 54 131.30 Ytterbium Yb 70 173.04 CHAPTER TWO2.4 TABLE 2.1 Chemical Elements (Continued ) Element Symbol Atomic No. Atomic weight b Yttrium Y 39 88.905 Zinc Zn 30 65.37 Zirconium Zr 40 91.22 a All the elements for which atomic weights are listed are metals, except as otherwise indicated. No atomic weights are listed for most radioactive elements, as these elements have no fixed value. b The atomic weights are based upon nuclidic mass of C 12 ϭ 12. c Inert gas. d Metalloid. e Liquid. f Gas. g Most active gas. h Lightest gas. i Lightest metal. j Not placed. k Liquid at 25ЊC. l The atomic weight varies because of natural variations in the isotopic composition of the element. The observed ranges are boron, ע0.003; carbon, ע0.00005; hydrogen, ע0.00001; oxygen, ע0.0001; silicon, ע0.001; sulfur, ע0.003. m The atomic weight is believed to have an experimental uncertainty of the following magnitude: bromine, ע0.001; chlorine, ע0.001; chromium, ע0.001; copper, ע0.001; iron, ע0.003; silver, ע0.001. For other elements, the last digit given is believed to be reliable to ע0.5. Source: From Avallone and Baumeister. 1 different chemical elements are due to the different numbers of these smaller par- ticles composing them. In a hydrogen atom, there is one proton and one electron; in a radium atom, there are 88 electrons surrounding a nucleus 226 times as massive as the hydrogen nucleus. Only a few, in general the outermost or valence electrons of such an atom, are subject to rearrangement within, or ejection from, the atom, thereby enabling it, because of its increased energy, to combine with other atoms to form molecules of either elementary substances or compounds. The atomic number of an element is the number of excess positive charges on the nucleus of the atom. The essential feature that distinguishes one element from another is this charge of thc nucleus. It also determines the position of the element in the periodic table (Table 2.2). Modern research has shown the existence of isotopes, that is, two or more species of atoms having the same atomic number and thus occupying the same place in the periodic system, but differing somewhat in atomic weight. These isotopes are chemically identical and are merely different species of the same chemical element. Data for solubility of inorganic substances and gases in water are given in Tables 2.3 and 2.4, respectively. Sec Refs. 1 and 3 for information on other chemical properties of materials. THERMOPHYSICAL PROPERTIES Most frequently used thermophysical properties in engineering practice are Density ( ␳ ) Specific heat (c) Specific heat at constant pressure (c p ) Thermal conductivity (k) 2.5 TABLE 2.2 Periodic Table of the Elements . Handbook of Engineering Fundamentals, John Wiley & Sons, New York, 1975. 5. T. G. Hicks, Standard Handbook of Engineering Calculation, 2d ed., McGraw-Hill, New York, 1985. 6. R. H. Perry, Engineering. ONE1.18 TABLE 1.6 Conversion Factor g c for the Common Unit Systems Quantity Si English engineering* cgs‡ Metric engineering Mass kilogram, kg pound mass, lb gram, g kilogram mass, kg Length meter,. SI. There are really no sound reasons for these fears. SI is a logical, easily understood, and ENGINEERING UNITS 1.19 readily manipulated group of units. Most engineers grow to prefer SI, once