Standard atmosphere 379 table

The U.S. Standard Atmosphere (Table A.8) gives mean conditions at 45°N latitude. From Figure 1.2 we note that the change of temperature with altitude varies with latitude. Throughout this book we will need the variation of atmospheric properties as a function of altitude. For this we will generally use the U.S. Standard Atmosphere. 

It was assumed initially that Haynes 230 and Ni-Cr-Mo alloys would have common corrosion characteristics. So taking into account the model by Quadakkers and Schuster [7] and the composition of the standard atmospheres (Table 26.1), we designed test helium with a likely composition containing H2, CO and CH4. No water was purposely added but the residual amount of water vapour was about 2 ppm. The selected gas mixture should promote oxidation of the materials, provided that their Cr activity is higher than about 0.4 at 950°C. Table 26.3 gives the steady state potentials in the test atmosphere using the equations developed by Quadakkers and Schuster [7]. 

TABLE 2-236 Thermodynamic Properties of the International Standard Atmosphere ... 

TABLE 12-1 Thermodynamic Properties of Moist Air (Standard Atmospheric Pressure, 29 921 inHg)... 

Tensile strength of the fibers is also determined by the refinement of the fiber [14] (Fig. 4). Hydrophilic properties are a major problem for all cellulose fibers. The moisture content of the fibers amounts to 10 wt% at standard atmosphere. Their hydrophilic behavior influences the properties of the fiber itself (Table 3) as well as the properties of the composite at production [15]. 

The temperature at which a liquid hoils is not constant, hut varies with the pressure. Thus, while the hoiling point of water is commonly taken as 100°C, this is only true at a pressure of one standard atmosphere (1.013 har) and, hy varying the pressure, the hoiling point can he changed (Table 1.1). This pressure-temperature property can he shown graphically (see Figure 1.2). 

An important extension of this relationship is its application to the evaporation of liquids into a given atmosphere, such as air. Consider the evaporation of water into air (Xo2 = 0.21 and Xy, = 0.79). Suppose the air is at 21 °C. If the water is in thermal equilibrium with the air, also at 21 °C, its vapor at the surface must have a vapor pressure of 0.0247 atm (from standard Steam Tables). However, if the water and the air are at the same temperature, no further heat transfer can occur. Therefore no evaporation can take place. We know this cannot be tme. As discussed, in the phenomenon of evaporative cooling , the surface of the liquid water will have to drop in temperature until a new equilibrium p(T) can satisfy the conservation laws, i.e. 

Some Sl-derived units with special names are included in Table 2.2. The standard atmosphere may be used temporarily with SI units it is dehned to be equal to 1.01325 X 10 Pa. The thermochemical calorie is no longer recommended as a unit of energy, but it is defined in terms of an SI unit, joules, symbol J, as 4.184 J [4]. The unit of volume, liter, symbol L, is now defined as Idm. ... 

The atmosphere is made up of a number of gases and, near the earth s surface, water vapor as well. The pressure exerted by atmospheric air is referenced to sea level. Average atmospheric pressure is 1013 mbar (equivalent to the atmosphere , a unit of measure used earlier). Table VIII in Chapter 9 shows the composition of the standard atmosphere at relative humidity of 50 % and temperature of 20 °C. In terms of vacuum technology the following points should be noted in regard to the composition of the air ... 

Resistance to Water in Snlfnr-Dioxide-Containing Atmospheres. For standards, see Table 1 ( Corrosion testing S02 and S02 resistance ). General conditions are standardized for exposing samples to a varying climate where water condenses in the presence of sulfur dioxide, so that tests in different laboratories give comparable results. The test allows rapid detection of defects in corrosion-inhibiting systems. 

As a result of atmospheric pollution levels that exceed the National Ambient Air Quality Standards (NAAQS) in many parts of the United States, both the federal government and the State of California have implemented standards for exhaust and evaporative emissions from new vehicles (see Exhaust control, AUTOMOTIVE). The first of these standards went into effect in 1968 and mandated that the vapors from the vehicle crankcase be routed back through the engine and burned. Since then, the standards have continued to grow stricter. Table 7 shows the federal exhaust emission standards and Table 8 shows the more stringent California standards. California has mandated that starting in 1998 a certain percentage of new vehicles sales must be zero emissions vehicles (ZEV). 

The inlet pressures listed in the table are gauge pressures the pressures used in the calculations of j and f are absolute pressures. Thus, atmospheric pressure had already been accounted for in the inlet pressure. The outlet pressure is taken as standard atmospheric pressure. As an example, for a measured gauge pressure of 137.9 kPa (20 psig), the ratio Pjabs/P0 is 2.361. The actual value of the atmospheric pressure will vary day to day, and with altitude thus if an exact value for j or f is desired, local pressure measurements must be made. 

The fraction of 0( D) atoms that form OH is dependent on pressure and the concentration of H2O typically in the marine boundary layer (MBL) about 10% of the 0( D) generate OH. Reactions (2.7 and 2.8) are the primary source of OH in the troposphere, but there are a number of other reactions and photolysis routes capable of forming OH directly or indirectly. As these compounds are often products of OH radical initiated oxidation they are often termed secondary sources of OH and include the photolysis of HONO, HCHO, H2O2 and acetone and the reaction of 0( D) with methane (see Figure 9). Table 2 illustrates the average contribution of various formation routes with altitude in a standard atmosphere. 

The steam/water enthalpy and entropy values for calculation of AG came from the steam tables and Mollier chart. See also Kotas (1995), p. 239, for moist standard atmosphere analysis. 

Temperature profiles have been measured for many years throughout the troposphere and are well summarized (41,243,244). The representative profiles for various seasons and latitudes in Table I are taken from the U.S. Standard Atmosphere Supplements (1966). 

Ibf) force to accelerate l(lbm) by 32.1740 (ft) s" atm = standard atmospheric pressure = 101 325 Pa (psia) E pounds force per square inch absolute pressure torr = pressure exerted by 1 mm mercury at 273.15 K (0°C) and standard gravity (cal) = thermochemical calorie (Btu) s international steam table British thermal unit (lb mole) s mass in pounds mass with numerical value equal to the molar mass (R) - absolute temperature in Rankines... 

Historically, the defined pressure for the standard state, i.e., the standard-state pressure, has been one standard atmosphere (101 325 Pa) and most existing data use this pressure. With the growing use of SI units, continued use of the atmosphere is inconvenient. lUPAC has recommended that the thermodynamic data should be reported for a defined standard-state pressure of 100 000 Pa. The standard-state pressure in general is symbolized as Previously in all JANAF thermochemical publications, was taken as 1 atm. In the current set of JANAF Thermochemical Tables p"" is taken as 100 000 Pa (1 bar). It should be understood that the present change in the standard-state pressure carries no implication for standard pressures used in other contexts, e.g., the convention that normal boiling points refer to a pressure of 101 325 Pa (1 atm). 

The boundaries between atmospheric layers are not rigidly fixed for example, the boundary between the troposphere and the stratosphere varies from an average of about 7,500 m (25,000 ft) near the poles to 17,000 m (55,000 ft) near the equator, and fluctuates seasonally. A reference profile, the Standard Atmosphere, is defined by the International Civil Aviation Organization to represent typical atmospheric conditions at midlatitudes (Table 4-1). At sea level, the Standard Atmosphere exerts a pressure of 760 mm of mercury (1 atm) and has a temperature of 15°C (59°F). (Note that English units are still in widespread use in the meteorology and aviation communities in the United States.) Pressure decreases approximately exponentially with increasing altitude at 5500 m (18,000 ft), pressure is half that at sea level. 

For comparison, from Table 4-1, the pressure at 610 m in a Standard Atmosphere is 0.94 atm. This small difference is partly attributable to the assumption of a constant temperature of 15°C with no vertical temperature variations. The temperature in a Standard Atmosphere at 610 m is only 11°C.)... 

TABLE 12-4 Thermodynamic Properties of Saturated Air (U.S. Customary Units, at Standard Atmospheric Pressure, 29+921 inHg)... 

Using empirical orthogonal functions (Dippner and Pohl, 2004) for a monitoring data set for the period 1993-2000 a positive trend in the order of one-third standard deviation appeared for dissolved Cd and Cu concentrations in surface waters of the B altic Proper. It was discussed that these trends were a result of a new stagnation period when the exchange with North Sea water was limited and the trace metal input via atmospheric and riverine sources resulted in the enrichment of trace metals in surface waters. This assumption was supported by the pollution loads entering the Baltic via rivers, industries, urban areas, and from the atmosphere (Table 13.2). 

Table 11.1 presents the standard atmosphere in equivalent units. Because there are so many different pressure units, the international community of scientists recommends that all pressure measurements be made using SI imits, but poimds per square inch continues to be widely used in engineering and almost aU nonscientific applications in the United States. 

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