Tables of Physical and Chemical Constants, and Some Mathematical Functions

Abstract

The metric standards of length and mass are kept at the International Bureau of Weights and Measures in the Pavilion de Breteuil, Sevres, near Paris. The Bureau is jointly maintained by the principal civilized governments as members of the Metric Convention. The use of metric weights and measures was legalized in the United Kingdom in 1897. LENGTH Unitthe centimetre, 1/100 of the international metre, which is the distance, at the melting-point of ice, between the centres of two lines engraved upon the polished " neutral web " surface of a platinum-iridium bar of a nearly X-shaped section, called the International Prototype Metre. DERIVED C.G.S. UNITS Velocity :-Unit-\ cm. per second. Angular Velocity :-Units-I radian (57°-2C;6) per sec. ; I revolution per sec. Acceleration :-Time rate of alteration of velocity. Unit-(i cm. per sec.) per sec. Angular Acceleration :-Units-I radian per sec. 2 ; i revolution per sec. 2 Momentum :-Mass multiplied by velocity. Uniti gm. cm. sec.-1. Moment of Momentum :-Momentum multiplied by distance from axis of reference. Unit-I cm. 2 gm. sec.-1. Moment of Inertia :-~s ,md?,where m is the mass of any particle of a body, and d its distance from the axis of reference. Unit-i cm. 2 gm. (see p. 16). Angular Momentum :-Moment of inertia multiplied by angular velocity round axis of reference. Unit-I cm. 2 gm. sec.-1. Porce :-Measured by-the acceleration it produces in unit mass. Unitthe dyne = cm. gm./sec. 2 Gravitational unitthe weight of I gram = g dynes. Couple, Torque, Turning Moment :-Force multiplied by distance from point of reference. Uniti dyne cm. Work :-Force multiplied by distance through which point of application of force moves in direction of force. Unitthe erg = I dyne cm.; I joule = lo 7 ergs. [i calorie = 4-18 joules]. Gravitational unitweight of I gm. x i cm. =^dyne cms. = g ergs. Energy :-Measured by the work a body can do by reason of either (i) its motion-Kinetic Energy (= mv 2 /2) or (2) its position-Potential Energy. Unit-the erg. (See "Work.") 1 Board of Trade Unit = 1 kilowatt hour = 3'6 x io 8 watt-sees. Power :-Work per unit time. Unit-1 erg per sec. 1 watt = io T ergs per sec. = 1 joule per sec. = 1 volt-ampere. 1 kilowatt = 1*34 horsepower. Pressure, Stress :-Force per unit area. Unit-1 dyne per cm. 2 1 megabar = io 6 dynes per cm. 2 =; 750 * mm. mercury at 0°C, lat. 45 , and sea-level (g = 980-6). 1 atmosphere = 760 mm. mercury at 0°C, lat. 45°, and sea-level = 759/4 mm. mercury at o°C. in London = J/0132 x io 6 dynes per cm. 2 = 147 lbs. per inch 2 = o-94 ton per foot 2. »^,. t. ... 7T tr • • Correct to I part in 5000. Elasticity :-Ratio of stress to resulting strain. Unit-1 dyne per cm. 2 , since the dimensions of a strain are zero. HEAT UNITS Temperature :-The melting-point of pure ice under 1 atmosphere is defined as o°C, and the boiling-point of water under 1 atmosphere as ioo°C. This fundamental interval is divided into 100 parts by use of the constant-volume hydrogen thermometer (see p. 44) ; each part is a degree Centigrade. Dimensions of temperature ...

Continuous measurements of water tensions in the xylem of trees based on the elastic properties of wood

“…6 and rates of transpiration. The stainless-steel rods used in the frame were an austenitic steel (A2 class 70, 18% chromium 8% nickel) which has tabulated values of a between 14.7´10 A6 á°C A1 , and 16.9´10 A6 á°C A1 (Colombier and Hochmann 1967;Kaye and Labey 1986). However, measurements on sample material in our laboratory indicated a ®gure of 20´10 A6 á°C A1 which was used in the corrections.…”

Modelling the dynamics and thermodynamics of volcanic degassing

“…Values used are c v(melt) p1000 J kg -1 K -1 , c p(CO2) p1280 J kg -1 K -1 , and c v(CO2) p1091 J kg -1 K -1 (at 1200 K; Kaye and Laby 1986). Assuming that the density of any crystal fraction is the same as the melt density, then the gas mass fraction (F) is related to the gas volume fraction (a) by:…”

Particle recycling in volcanic plumes

“…For pressures less than 20 atm, the dynamic viscosity of air is approximately proportional to the square root of its absolute temperature, and independent of the pressure (Kaye and Laby 1973). Our model atmosphere varies in temperature between from about 300 K at sea level to 230 K in the stratosphere, corresponding to a change in viscosity of around 14%.…”