Hole geometries

The overall effect of catalyst pellet geometry on heat transfer and reformer performance is shown in the simulation results presented in Table 1. The performance of the traditional Raschig ring (now infrequently used) and a modern 4-hole geometry is compared. The benefits of improved catalyst design in terms of tube wall temperature, methane conversion and pressure drop are self-evident. 

Table 4.3 The oxyanion hole geometry for selected tetrahedral intermediates and enolate intermediates. 

The oxyanion hole geometry of three complexes is visuahzed in Figures 4.2. 4. Figure 4.2 displays the active site of trypsin complexed with a peptide inhibitor [41]. In Figure 4.3, the active site of chymotrypsin complexed with a neutral aldehyde adduct is displayed [43], and in Figure 4.4, cutinase (a lipase) with a covalently bound phosphate, a transition state analog is depicted [63]. 

The effect of changed operating conditions or hole geometry on the pressure loss P at the discharge holes of the die plate can also be easily estimated with the help of the flow exponent m. The flow exponent for standard polymers is generally found to be between 2.5 and 3.5 (Fig. 11.13). 

Figure 5.22 Artifacts generated by tip (a) the side of tip causes broadening of the image of the protruding object and (b) limits in the width the of tip limits cause distortion of the hole geometry in the image. (Reproduced with permission from P.C. Braga and D. Ricci (eds), Atomic Force Microscopy, Humana Press. 2004 Humana Press.)...

In addition, molded holes can be custom designed to aid in insertion of leaded components (entry radii or countersink) or to provide recessed mounting of hardware (counterbore). Furthermore, holes can be oblong, rectangular or parallel to the plane of the molded substrate. Possible hole geometries are illustrated in Figure 1. 

For very low vapor pressures (below about 10 Pa), the vapor pressure can be measured by the Knudsen method, in which the rate of escape of vapor through a small hole is measured. The kinetic theory of gases (with correction factors for hole geometry, etc.) is used to relate the rate of effusion to the vapor pressure. The attainable accuracy of such methods is around 1% to 10% at best, but it is often the only experimental option for substances of very low volatility. 

Powders were placed in subsurface drilled holes. The hole geometry provided good control of the volume fraction. A number of ceramic and metallic phases were explored, including a combination of SiC and MoSj. 

Heinemann RK (2012) The effect of starting hole geometry on borehole quality and tool life of twist drills. International journal of advanced manufacturing technology 60(5-8) 519 526. doi 10.1007/s00170-011-3625-7... 

The machining process is mainly determined by the cutting geometry in the front of the reamer. The geometry is mostly responsible for the diameter, hole geometry, surface quality, and chip evacuation. 

Following Pedersen [78], there are three main contributions that have to be incorporated when a typical diffractometer with a pin-hole geometry is used wavelength spread, coUimation effects, and the detector resolution. Using a Gaussian function for each effect, the resolution function is given by ... 

Glogowski and Castillo [37] used the reverse plate bending test to evaluate cast bronze alloys in paper mill white waters. Rectangular bars with holes drilled to simulate those in suction rolls were tested in accordance with TAPPI Technical Information Paper 0402-08 with simulated white water containing thiosulfate wicked into the holes [33], This test is better than the rotating beam test as a simulation of the fatigue that occurs at suction roU holes, since it incorporates a drilled hole geometry. 

Schematic of pressure hole geometry showing curvature of the streamlines near the mouth of the hole or slot. The difference between the pressures measured by the flush-mounted and recessed transducers gives the hole pressure, p = p, - p, ,.

Undercut anchors transfer tension loads to the base material via bearing rather than fiiction, and as such offer a generally more rehable mechanism for resisting applied loads. This is achieved by producing a hole geometry (that is, an undercut) that permits the anchor to key into the base material. 

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