Air gap width

C Consider three similar double-paue windows with air gap widths of 5, 10, and 20 nim. For which case will the heal transfer through the window will be a minimum ... 

The process parameters influencing the water vapor flux and energy efficiency are the temperature difference between hot and cold solutions, flow velocities of feed and permeate, air gap pressure, air gap width, and membrane type. 

External diameter of stator (mm) Internal diameter of stator (mm) Air-gap width (mm) External diameter of rotor (/mm)... 

Flow is solved using electrical circuit theory, where airflow is analogous to current flow and flow resistance is caused by fabric permeability and Poiseuille flow resistance through the air gaps between fabric layers. Nodal analysis is used to solve sub-elements of the circuit and identifies each junction and KirchofTs current law is applied to conserve flow at each junction. The model can be modified to represent a complex variation in air gap width and complexities in clothing geometry and structures, such as seams. 

To solve the problem of heat loss by conduction through the membrane, which leads to relatively low efficiency of the MD process, an air gap was placed inside the membrane module between the permeate side of the membrane and the condensing surface. This reduces considerably both the heat loss by conduction and temperature polarization, thereby improving the separation effect. However, the permeate flux has to overcome the air barrier, and, therefore, it is drastically reduced, depending on the effective air gap width. On the other hand, because permeate is condensed on a cold surface rather than directly on membrane surface, air gap MD (AGMD) can be applied in fields where the DCMD is limited such as the removal of organic compounds from aqueous solutions. 

Figure 12.21 Effect of air gap width on AGMD flux and ethanol selectivity of HVHP (Table 12.1). 50°C feed temperature, 20°C cold temperature, 0.0155 weight fraction ethanol in feed (Banat and Simandl, 1999).

Note The shaft deflection should not be more lhan 11% of the air gap between the stator and the rotor. For loads that exert more force and torsional stress on the motor shaft and bearings than is permissible, due to the larger width of pulleys which may shift the... 

The inductance of an iron-cored inductor varies with any air gap included in the iron core. Thus, physical movement can be detected by allowing this movement to displace part of the core, so changing the width of the gap. The detection of very small movements is possible in this way, and instruments based on the principle are used to measure acceleration, pressure, strain, thickness and a variety of other changes. 

Fig. 5.82 Double shell brick walls with air gap of width <5...

The MIE occurs at an optimal spark gap width and varies with temperature, pressure, and oxidant concentration. The MIEs of flammable gases are usually 0.01-1.0 ml in air and 0.002-0.1 ml in oxygen. The MIE of gases and vapors can be determined using the method of ASTM E582. 2>... 

In contrast, the briquetting or compacting of some other materials demands a degree of compaction that cannot be achieved by a single pass in a choke-fed roller press, irrespective of the ratio of pocket size (or gap width) to roll diameter. In addition, redistribution of material (which may be extensive) from the nip against the flow of material or from the rear of cups into following cups, e.g. due to the flow of displaced air, may further reduce the efficiency of compaction. 

The Ir/Pd-MOS condensator described in Section 3.1.21.1 (Winquist et al., 1985) has also been combined with urease to form a urea probe. Urease was entrapped between a dialysis membrane and an NH3-per-meable foil, the latter being separated from the MOS structure by an air gap of 0.1 mm width (Fig. 72). The measuring range was 0.01-5 mmolA, the response time being 3 min. The sensor had an operational lifetime of only 4 days. 

The main parameters for controlling the treatment process include the voltage, width of the air gap, film/web speed, and the width of the electrodes. Most machines allow treatment of one side of the web (Fig. 7.9) and require two passes for two-sided treatment. There are machines that are equipped with two sets of electrodes for one pass, two-sided treatment. 

In a relatively new development, the distribution plate in a batch fluid-bed granulator is replaced by a solid rotating plate fitted into a conical bottom section [B.97]. Process air enters the apparatus through the annular space between the plate and the container walls. Its amount can be varied by changing the annular gap width... 

Deryagin and Abrikosova [42] determined the force of interaction in air and in vacuum, with gap widths from 0.1 to 1 fxm separating the contiguous bodies these results were used in evaluating adhesion in a liquid medium since such adhesion typically involves gap widths of this order. The forces of interaction were not measured with the bodies in direct contact such measurements would have been of great interest in the study of adhesion in an air medium. 

Initial die gaps are set to about 20 percent greater than the final film thickness, and then adjusted to accommodate changes in polymer flow which are resin and rate sensitive. Higher screw speeds increase extruder output, overall film thickness, the tendency toward melt fracture, and may alter the flow pattern. Thus, extruder speed is not a recommended control. In contrast, increased chill-roll speeds decrease film thickness, reduce film width due to increased neck in, increase uniaxial orientation, and alter the optimum air gap or drawdown distance. The optimum air gap, which produces the best orientation, crystallization, and surface properties, depends on the material and chill-roll speed. At 23 to 30 m/min (75 to 100 ft/min), the air gap for low-density polyethylene is about 100 mm (4 in), but when the line speed increases, the air gap is found by trial and error, Since the chill-roll speed controls film stretching, the take-off speed has little effect on the film dimensions. 

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