Direct Air Injection

FIGURE 2.4 Foam generation by direct air injection. (Reprinted from J. Colloid Interface ScL, 263, Zhang, H., Miller, C.A., Garrett, RR., Raney, K., 633. Copyright 2003, with permission from Elsevier.) 

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The simulated test atmosphere with high levels of contaminant (2 to 5ppm) were analyzed by both the in-line GC (in the primary dilution module) and by direct injection of air taken from the sampling port (in the secondary dilution module). The purpose of the latter was to establish the reliability of the in-line GC. The in-line monitor was particularly important in test atmosphere with low contaminant concentration because in this case, direct injection of the air is not feasible. Table I compares the results obtained by the in-line GC and direct air injection for ethylene oxide and acetone. 

Atomic absorption spectroscopy is an alternative to the colorimetric method. Arsine is stiU generated but is purged into a heated open-end tube furnace or an argon—hydrogen flame for atomi2ation of the arsenic and measurement. Arsenic can also be measured by direct sample injection into the graphite furnace. The detection limit with the air—acetylene flame is too high to be useful for most water analysis. 

G. P. Blair and co-workers, "The Reduction of Emissions and Euel Consumption by Direct Air-Assisted Euel Injection iato a Two-Stroke Engine," The 4th Gracy Two-Wheeler Symposium, Technical University, Gra2, Austria, 1991. 

Humidification The process of adding moisture to air by spinning disk, ultrasonic, steam, direct water injection, or other methods. 

Heat recovery tor steam generation, pre-heating combustion air, and high efficiency burners Adjustable speed drives, heat recovery coke oven gases, and dry coke quenching Efficient hot blast stove operation, waste heat recovery for hot blast stove, top gas power recovery turbines, direct coal injection... 

The use of direct steam injection into air is a common method of increasing humidity levels for both commercial and industrial applications. The process kills most types of bacteria and similar organisms that may contribute to fouling, health, or other indoor air quality (IAQ) problems. Where amines are present in the steam, however, even small concentrations can be detected by their odor and may be objectionable, even though they may be well under guidelines for concentrations in air. 

Aerobic treatment of aquifer oxygen is usually supphed by one of three methods direct air sparging of air or oxygen into wells screened below the contaminated zone, saturation of water with air or oxygen prior to reinjection, or addition of an oxidant (typically a peroxide compound) directly into an injection well or injection water. Regardless of the mechanism of introduction, the important factor is that the oxidant is distributed throughout the contaminated zone at a concentration and rate such that it can be utilized by the microorganisms. 

Thermal desorption (TD) (see Section 2.6.1) compared with solvent desorption of adsorbent tubes requires less preparation since the samples are transferred on-line from the desorber to the GC. TD of indoor SVOC samples from Tenax TA tubes and quartz fiber filters is possible (Clausen and Wolkoff, 1997b) and air samples of phthalates from chamber studies are easily analyzed using TD (Clausen et al., 2004). TD recovery may be estimated by comparing spiked tubes with direct solvent injection using the same GC (Clausen and Wolkoff, 1997b). 

All of these NOx-reducing reactions are much more rapid and effective than the catalyzed direct redox reaction (Eq. 3.9), and hence convert most of the NOx to innocuous gases. After NOx reduction, secondary air injection. 

Direct cylinder injection is more technologically sophisticated and involves forming the fuel-air mixture inside the combustion cylinder after the air intake valve has closed. 

Figure 3.9 Far-field directivity of Mj = 1.38 with (J — air injection at 500 psia) and without (2 — normal jet) microjet injection. Nozzle temperature ratio = 3.

Most AEC methods use direct sample injections vial a sample loop, thus achieving adequate detection limits." " Aqueous sample matrices usually do not require any sample pretreatment other than possibly filtration prior to injection. For matrices such as airborne particles, soil, or filters from air collection devices, organic acids are commonly transferred into an aqueous solution which can then be injected directly into the ion chromatograph. ° ° ... 

However, with the breaktlirough created for the sake of the two stroke engines in gasoline direct injection, notably by Siemens, or with air injection, (orbital or lAPAC) the 4 stroke lean bum engine is clearly a potential winner for tomorrow s green house engines. Already existing results evidence this forecast. 

Let s consider the moving front of combustion to be a real surface with a height of 21. At first, the combustion process is initiated right next to the injection well. The radius of the initial combustion front coincides with the well radius . The heat losses take place in a vertical direction from the combustion zone. The consumption of air injected into the bed is taking place at a steady rate, so that the shift of the burning front occurs at a rate inversely proportional to its distance from the well axis, that is... 

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