Dwell-time

Low pressure presses are usually operated at about 180°C as compared to high pressure presses at about 135°C, but the extra low pressure press heat is not adequate to compensate for the short dwell time. Special fast curing resins must be used in conjunction with the low pressure presses. 

Sodium hydroxide, potassium hydroxide, or other caustic compounds are blended to make these types of removers. Polymer-type thickeners are added to increase the viscosity that allows the remover to be appHed with a bmsh, trowel, or spray. Some of these products use a paper or fabric covering to allow the remover finish mixture to be peeled away. The most common appHcation for this group of removers is the removal of architectural finishes from the interior and exterior of buildings. The long dwell time allows for many layers of finish to be removed with one thick appHcation of remover. 

The actual compression process is a cycle of die fill, compaction by intervention of the upper punch using great pressure on the granulation material in the die, and upward movement of both punches to achieve ejection of the tablet from the die. Singe-punch presses have only one die-and-punch arrangement and the compression is quick, with Httle dwell time of the top punch in die. 

The relative abundance of neutral SiH and H2 species have been measured as a function of power, pressure, flow rate, and dilution. For low power levels, eg, 5 W, up to 50% of the SiH gas is dissociated and the percentage increases to 80% for a power of 50 W. The decomposition of SiH gas proceeds more readily with lower flow rates. These observations, coupled with infrared (ir) measurements performed on the films, suggest that deposition under conditions in which the silane gas is not entirely decomposed leads to a majority of SiH units, whereas those deposited under conditions in which silane is strongly dissociated contain a majority of dihydride units leading to a deterioration of the semiconductor. Also, when the dwell time of SiH in the plasma region increases, the resultant film exhibits a pronounced peak at 2090 cm from the ir spectra corresponding to S1H2 inclusion. 

Dried film (0.025 mm) oa paper cast from 10 wt % resia ia 60 40 tolueae ethanol heat sealer dwell time, 1.5 s at 0.4 MPa (60 psi). 

A loop tack (Fig. 2c) test consists of allowing a tear-shaped loop of conditioned tape to drape into contact with a test surface of specified area (usually 25.4 x 25.4 mm), with the force of contact limited to the weight of the tape itself (ASTM Ref. D-6195). The ends of the loop are held in a tensile tester. After a momentary contact time the tester is engaged and the tape is removed at a specified speed. The maximum in the removal force is ordinarily observed just at the point where the two peel fronts Join. The value is reported in a force per area of tape width, or lb in. -. While this tack test has some popularity, it is perhaps more of a very short dwell time peel test, and it has variables more associated with that test, especially backing effects, since heavier backings lead to higher tack values. 

Probe tack. A probe (flat or not) is contacted with an adhesive film at a given pressure and dwell time. The force required to remove the probe from the adhesive is a measure of tack [30]. 

Residence and Relaxation Times (a) Residence (or Dwell) Time... 

Dwell time = 1 second so flow is predominantly elastic. 

The packet thus formed was filled with the food product to be tested and the open side was heat sealed. Heat seals were usually made at 350°F jaw temperature, 40 psi pressure with 0.5 second dwell time the exact conditions necessary depend on the materials used and caliper. This produced a packet with an 8 sq. in. total area. 

Abstract After a recall of the constraints in the construction of new large telescopes and of the shape of mirrors and associated aberrations, one addresses methods of polishing as dwell time, and bend and polish ones. 

Each "tool" has a unique footprint or wear pattern that is a function of its diameter. This wear pattern is eonvolved with the topographic map of material to be removed to create the raster pattern with a dwell time at eaeh raster position. In some implementations, these dwell time methods work very well. A faetor of 10 improvement in surfaee figure is common for the ion beam and MRP methods but there are some definite issues as well. 

Another problem with all the dwell time methods is that sinee a speeifie diameter tool is often used to do the polishing, the finished surfaee has a "roughness" of a spatial frequency associated with the tool diameter. This rather eo-herent roughness ean produce diffraction artifacts in the image produeed by the telescope. A partial solution to this problem is to use several tool sizes and do the figuring in stages rather than all at onee. 

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