Surface average

A realistic assessment of biomass as an energy resource is made by calculating average surface areas needed to produce sufficient biomass at different aimual yields to meet certain percentages of fuel demand for a particular country (Table 2). These required areas are then compared with surface areas available. The conditions of biomass production and conversion used ia Table 2 are either within the range of 1993 technology and agricultural practice, or are beheved to be attainable ia the future. 

Similarly, the diameter of average surface area (mean surface area diameter), assuming sphericity, can be expressed as in equation 3 and is used when the surface behavior of the particle system is of importance. 

The surface-area mean (sm) diameter, not to be confused with the number-based average surface area (eq. 3), also known as the Sauter diameter, can be calculated as follows ... 

In this work the state-of-the-art and perspectives of column characterization and compai ison have been presented and discussed. All information about physico-chemical properties of RP HPLC Cl8 and C8 columns as porosity, average surface area, free silanol concentration, binding ligand density and others, were summarized. The points of views about column classifications, its advantages and disadvantages were discussed. It was shown that Cl8 and C8 HPLC column classification processes do not allow selecting the column with the same or preai range selectivity. 

Thus, as for XP S, the average surface concentration Na can, in principle, be calculated by measurement of the Auger current, according to Eq. (2.13). Again, as in XPS, relative sensitivity factors are generally used. The Auger current for the same transition XYZ in a standard of pure A is measured under the same experimental conditions as in the analysis of A in M, whereupon the ratio of the atomic concentrations is... 

In buildings away from outside perimeter walls, air and surface temperatures are usually approximately equal. The heat losses from a person by radiation (q ) and convection (q ) are then flowing to the same temperature level. In such uniform spaces, the radiant and convective losses are about equal and together account for about 80-90% of the total heat loss of a sedentary comfortable individual. In the presence of hot or cold surfaces, as may occur in perimeter or other locations in a building, the average surface temperature of the surroundings (called mean radiant temperature) as seen by the person s body may be substantially different from air temperature. If the mean radiant temperature (MRT) is greater or less than air temperature (T,) the person will feel warmer or colder than in a thermally uniform space where MRT =. ... 

Values of Cp for simple building geometries may be obtained from the British Standards Institution or from Liddament. The following relationship between wind incident angle a, building side ratio, and average surface pressure coefficient is based on the database developed by Swami and Chandra ... 

In this way, by taking the average over the field 4> and computing the Euler characteristic for the average surface given by (f)) = 0, we can easily discern between different ordered phases. In this example (Fig. 13) the snapshot... 

In the structure with all the surfactant molecules located at monolayers, the volume fraction of surfactant should be proportional to the average surface area times the width of the monolayer divided by the volume, i.e., Ps (X Sa/V. The proportionality constant is called the surfactant parameter [34]. This is true for a single surface with no intersections. In our mesoscopic description the volume is measured in units of the volume occupied by the surfactant molecule, and the area is measured in units of the area occupied by the amphiphile. In other words, in our model the area of the monolayer is the dimensionless quantity equal to the number of amphiphiles residing on the monolayer. Hence, it should be identified with the area rescaled by the surfactant parameter of the corresponding structure. 

For diffuse and delocahzed interfaces one can still define a mathematical surface which in some way describes the film, for example by 0(r) = 0. A problem arises if one wants to compare the structure of microemulsion and of ordered phases within one formalism. The problem is caused by the topological fluctuations. As was shown, the Euler characteristic averaged over the surfaces, (x(0(r) = 0)), is different from the Euler characteristics of the average surface, x((0(r)) = 0), in the ordered phases. This difference is large in the lamellar phase, especially close to the transition to the microemulsion. x((0(r)) =0) is a natural quantity for the description of the structure of the ordered phases. For microemulsion, however, (0(r)) = 0 everywhere, and the only meaningful quantity is (x(0(r) = 0))-... 

The surface-emissive powers of fireballs depend strongly on fuel quantity and pressure just prior to release. Fay and Lewis (1977) found small surface-emissive powers for 0.1 kg (0.22 pound) of fuel (20 to 60 kW/m 6300 to 19,000 Btu/hr/ ft ). Hardee et al. (1978) measured 120 kW/m (38,000 Btu/hr/ft ). Moorhouse and Pritchard (1982) suggest an average surface-emissive power of 150 kW/m (47,500 Btu/hr/ft ), and a maximum value of 300 kW/m (95,000 Btu/hr/ft ), for industrialsized fireballs of pure vapor. Experiments by British Gas with BLEVEs involving fuel masses of 1000 to 2000 kg of butane or propane revealed surface-emissive powers between 320 and 350 kW/m (100,000-110,000 Btu/hr/ft Johnson et al. 1990). Emissive power, incident flux, and flame height data are summarized by Mudan (1984). 

TABLE 6.2. Average Surface-Emissive Powers Measured in the Tests Performed by British Gas ... 

Test No. Fuel Mass (kg) Release Pressure (bar) Average Surface-Emissive Power (kWIm )... 

Emissive Power. Pape et al. (1988) used data of Hasegawa and Sato (1977) to determine a relationship between emissive power and vapor pressure at time of release. For fireballs from fuel masses up to 6.2 kg released at vapor pressures to 20 atm, the average surface-emissive power E can be approximated by... 

The surface-emissive power E, the radiation per unit time emitted per unit area of fireball surface, can be assumed to be equal to the emissive powers measured in full-scale BLEVE experiments by British Gas (Johnson et al. 1990). These entailed the release of 1000 and 2(XK) kg of butane and propane at 7.5 and IS bar. Test results revealed average surface-emissive powers of 320 to 370 kW/m see Table 6.2. A value of 350 kW/m seems to be a reasonable value to assume for BLEVEs for most hydrocarbons involving a vapor mass of 1000 kg or more. 

PEM (Pollution Episodic Model) is an urban scale air pollution model capable of predicting short-term average surface concentrations and deposition fluxes of two gaseous or particulate pollutants. 

Table 2.15 Average surface temperature of the oceans between parallels of latitude (°C)...

Recent space-probe and earth-based spectroscopic studies of the planet Venus suggest how much remains to be learned about the other planets. Earlier estimates of the surface temperature of Venus placed it near 60°C. The more detailed studies show, however, that two characteristic temperatures can be identified, —40°C and 430°C. The lower temperature is attributed to light emitted front high altitude cloud tops. The higher temperature is likely to be the average surface temperature. 

Since Bis via Gauss s Law of electrodynamics proportional to the local excess free charge it follows that the term fjeV VGj is proportional to the net charge stored in the metal in region G. This net charge, however, was shown above to be zero, due to the electroneutrality of the backspillover-formed effective double layer at the metal/gas interface and thus Dfje w.Gj must also vanish. Consequently Eq. (5.47) takes the same form with Eq. (5.19) where, now, O stands for the average surface work function. The same holds for Eq. (5.18). 

Average surface temperature of chaparral/brushland fires... 

Vermaak IS, Kuhhnann-Wilsdorf D. 1968. Measurement of the average surface stress of gold as a function oftemperature in the temperature range 50-985 °C. J Phys Chem 72 4150-4154. 

Location Average length/diameter (cm) Average surface area (m2) Average pH (range) Enzymes and others Mean transit times Microflora per gram content... 

As noted in Table I, average surface radium concentrations appear to vary by about a factor of 20. This can also be seen from the distributions from the NARR data. Soil permeabilities, on the other hand, have much larger variations, and thus, in principle, may have a greater influence on the spatial variations in average indoor radon concentrations that have been observed. As with the case of surface radium concentrations, the spatial variability of air permeabilities of soils is an important element in developing a predictive capability. 

---