T-shaped die

Sheet die design equations were first developed by Carley (59) for T-shaped dies using Newtonian fluids. Pearson (60), whose basic approach we now elucidate, extended the design equations to Power Law fluids. The proper die design delivers a given polymer melt under specified conditions through a constant die opening at a constant rate and temperature (cross-machine direction uniformity). Here, we trace the development of a die... 

The most common die configuration for production of cast film and sheet is a coat-hanger die (Fig. 7.7), named because of its resemblance to a common coat hanger. T-shaped dies are also used. The die opening is wider and thicker than the finished film. As the film is drawn down between the die and the chill roll, it contracts in width and thins, due to tension on the film being produced and polymer relaxation effects. 

Sheeting die is a kind of extmsion die with a flat slot die lip that nsnally nsed for the molding of plastic sheet or flat film. The common sheeting die structures include T-shape die, fish-tail die and hanger die. Optimization for a sheeting die is to achieve a imiform flow distribution on the die lip so as to assme the qnality requirement on the extrinsic feature, mechanical property and dimensional precision of the final products. However, control for the process parameters and die stmctnre is now mainly depended on the experiences derived Ifom many times of trial and error method which inevitably cause a great waste of time and cost. 

In this particular case of a cylindrical pore shape, it seems reasonable to assume that the condensate has a meniscus of spherical form and radius rK. However, as some physisoiption has already occurred on the mesopore walls, it is evident that rE and rf are not equal. If the thickness of the adsorbed multilayer is t, and die contact angle is assumed to be zero, the radius of the cylindrical pore is simply... 

AgRuF BiF6 Synthesis. Ag(BlFe)2 (158 mg, 0.210 mmol) and LiRuF6 (44 mg, 0.20 mmol) were put into the same lube of a T-shaped FEP reactor. AHF ( 1.5 mL) was condensed onto die solids and warmed to room temperature. This mixture was stirred for 40 min as an olive-green solid was formed in a colorless solution. The solution was decanted and the AHF then distilled back onto the olive-green solid, leaving behind a while solid (shown by X-ray powder diffraction... 

Figure 6. T-Shaped micromixer formed by die intersection of two microchannels, showing a schematic of the mixing or dilution process.

Figure 8. 3D species concentration field for a 50pm x 50pm T-shaped micromixer resulting from die flow fields shown in Figure 7. (a) homogeneous case, and (b) heterogeneous case with offset patches. Species diffiisivity is SxlO mVs and zero electrophoretic mobility are assumed. 

Figure 2.25 illustrates a T-type die and a coat-hanger-type die, which are used for both film and sheet extrusion. The die must produce a smooth and uniform laminar flow of the plastic melt which has already been mixed thoroughly in the extruder. The internal shape of the die and the smoothness of the die surface are critical to this flow transition. The deckle rods illustrated in Figure 2.25 are used by the processor to adjust the width of the extruded sheet or film. 

An extruder die-box or head in the shape of a letter T used in wire covering. The rubber flow is thus at right angles to the direction of travel of the wire. 

Don t freak out when the plants go deciduous, usually about a year or a year and a half from sprouting. They drop almost all their leaves except the ones at the tip of the stems, turn yellow and mottled, and you think they re dying. They re not - in fact, they re growing Within a few days, little spike-shaped green sprouts will appear, and tiny, usually white, flowers. After a few years, the flowers will start producing little... 

Figure 6.10 Ultrafast efficient switching in the five-state system via SPODS based on multipulse sequences from sinusoidal phase modulation (PL). The shaped laser pulse shown in (a) results from complete forward design of the control field. Frame (b) shows die induced bare state population dynamics. After preparation of the resonant subsystem in a state of maximum electronic coherence by the pre-pulse, the optical phase jump of = —7r/2 shifts die main pulse in-phase with the induced charge oscillation. Therefore, the interaction energy is minimized, resulting in the selective population of the lower dressed state /), as seen in the dressed state population dynamics in (d) around t = —50 fs. Due to the efficient energy splitting of the dressed states, induced in the resonant subsystem by the main pulse, the lower dressed state is shifted into resonance widi die lower target state 3) (see frame (c) around t = 0). As a result, 100% of the population is transferred nonadiabatically to this particular target state, which is selectively populated by the end of the pulse.

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