Bulk air

Equation 13.50 gives the relation between liquid temperature, air enthalpy, and conditions at the interface, for any position in the tower, and is represented by a family of straight lines of slope —(ht/hop). The line for the bottom of the column passes through the point A( u,Hgi) and cuts the enthalpy-temperature curve for saturated air at the point C, representing conditions at the interface. The difference in ordinates of points A and C is the difference in the enthalpy of the air at the interface and that of the bulk air at the bottom of the column. 

Similarly, line A C , parallel to AC, enables the difference in the enthalpies of the bulk air and the air at the interface to be determined at some other point in the column. The procedure can be repeated for a number of points and the value of (Hf — Ha) obtained as a function of He for the whole tower. 

The bulk air-soil partition coefficient, Kiasoii, encompasses absorption into soil or-... 

The density of CO2 in the absorption cell, however, is a function of both concentration and bulk air density. In normal process analyzers, where temperature and pressure within the absorption cell are controlled, measurements can be easily referred to gas density by a simple calibration curve. In an open path system, changes in bulk air density must be measured. Indeed, one of the major problems faced in testing the sensor was the development of test facilities where we could control the temperature, pressure and CC>2 more accurately than the sensor could measure. Even the small changes in building pressure associated with ventilation system fluctuations resulted in output signal changes three to four times the sensor signal to noise level. In operation, pressure and temperature near the open cell are measured and used to calculate gas density. 

Unknown organic compounds can be identified and quantitatively measured by gas chromatography/mass spectrometry (GC/MS). Analytes can be thermally desorbed from the adsorbent surface and analyzed by GC/MS. Alternatively, the bulk air from the site collected in a Tedlar or a canister can be injected or introduced by heating or suction into the system for separation and analysis. 

Sulfur New Asphalt Soften- ing Agent Resilient Modulus Bulk Air Specific Voids Marshall Stability ... 

Table 14-1 provides a = 0.273, m s 0.635. Since the difference between the bulk air temperature... 

FIGURE 4-31 Dry deposition by absorption. Ca and Cs are chemical concentrations in bulk air and at the leaf surface, respectively. The chemical flux is determined in part by the thickness of the stagnant air boundary layer (shown for simplicity as having uniform thickness). This model is essentially the same as that applied to gas exchange between air and water for the case in which transport resistance is dominated by the air side (Section 2.3). 

Mass transfer of water vapor from the surface of the slab to the bulk air... 

A low-carbon steel tube with a 25.4 mm (1 in.) outside diameter is radially finned with an aluminum (Alloy 1100) strip 15.8 mm (0.625 in.) high and 0.483 mm (0.019 in.) average thickness uniformly spaced at 400 fins/m (10.2 fins/in.). The outside surface of the steel tube is 80°C (176°F), and the tube is cooled by air in cross flow, with a bulk air temperature of 30°C (86°F) with a film heat-transfer coefficient of 70 W/m K (12.3 Btu/h fF °F), assumed uniform over the entire outside surface... 

The ozone flux due to bulk air exchange is obtained by multiplying the exchange rate with an appropriate ozone mass mixing ratio in the lower stratosphere. Figures 3-4 and 5-5 suggest an average value of 1 pg/g. Both quantities are subject to seasonal variation, however. From observations of... 

In the foregoing definitions, subscript cr refers to the transition from unhindered to hindered drying in the falling rate period, e to equilibrium, 0 to the air inlet face of the fiber mass, G to the bulk air, and W to the wet bulb conditions. The holdup of solids on the band is F. 

The partial pressure of water vapor is the most commonly used concentration term in the paper industry therefore, Ac becomes the difference between the partial pressures of water vapor at the interface and in the bulk air. 

---