Effective section thickness

Moreover, the degree to which partial volume effects distort polyp morphology is determined by polyp size relative to the effective section thickness and section sensitivity profile, which are primarily a function of collimation, pitch and interpolation algorithm. For SSCT protocols with 3 mm and 5 mm collimation and pitch ranging between one and two, excellent depiction of 6-mm and 13-mm pedunculated polyps and 10 3 mm sessile polyps can be... 

Spatial resolution in the patient (z-axis) direction, determined by the effective section thickness and the image increment. 

In the tidal zone and the spray zone (known as the splash zone), cathodic protection is generally not very effective. Here thick coatings or sheathing with corrosion-resistance materials (e.g., based on NiCu) are necessary to prevent corrosion attack [4]. The coatings are severely mechanically stressed and must be so formed that repair is possible even under spray conditions. Their stability against cathodic polarization (see Section 17.2), marine growths, UV rays and seawater must be ensured [4,5]. 

Illumination of solar cells causes a reduction of efficiency and fill factor, as a result of light-induced creation of defects (Staebler-Wronski effect. Section 1.1.2.5). This reduction is halted after several hundred hours of illumination. The reduction is correlated with solar cell thickness. A large intrinsic layer thickness leads to a large reduction of efficiency and fill factor compared to a small intrinsic layer thickness. The solar cell properties can be completely recovered by annealing at about 150°C. The open circuit voltage and short circuit current decrease only slightly. 

Effect of Section Thickness Emulsion Type and Development on Resolution of EM Radioautographs... 

Variations in cross-sectional thickness of a part introduce added complexity to the die, since for maximum density uniformity each section must have its own ram (Figure 7.23). Although there are some restrictions on the complexity of parts that can be produced by die pressing, this method is suitable to automation and can be used to produce tens to possibly thousands of parts per minute (Richerson, 1992). As a set of dies usually requires a significant capital outlay, to be cost-effective, die pressing is typically limited to high-volume or high-value production parts. 

In many of the cross sections of pressure-atomized coatings, spherical voids are common and occasionally have diameters that are a significant fraction of the total coating thickness. This causes a localized decrease in the effective coating thickness (Figure 23) and may reflect gas entrainment associated with the relatively large size of the pressure-atomized sulfur droplets. 

Engberg et al. [67,68] prepared blends based on Vectra A950 and several flexible chain polymers. The order parameter of the PLC component in injection molded blends of polyethersulfone (PES) and Vectra, referring to the whole cross-section (thickness of specimen 1.5 mm), was according to X-ray scattering data close to 0.4 and also independent of the composition of the blend [67]. The lower chain orientation found in these samples reflects the fact that shear flow is less effective in orienting PLCs than extensional flow. 

Besides exploiting the interference effect due to the presence of the thin metal film over- and underlayers, it is possible to obtain an additional enhancement of the band intensities in aU the above-mentioned configurations by using multiple reflections. The maximum value of AR for the multiple-reflection method and the optimum number of reflections depend on the system considered (Section 2.4). However, when a relatively thick (3-20 nm) metal layer participates in the optial scheme, multiple reflections may not improve the quality of the spectrum because of the high absorption by the metal film. The spectrum contrast can be enhanced if the metal layer has islandlike structure, due to an increase in the effective surface and the SEIRA effect (Section 3.9.4). 

In extrusion, the preheated material is forced out of the extruder with a screw (Figure 12-2) or double screw and allowed to cool in a bath or in the air. Thermoplasts, elastomers, and thermosets are extruded. As a rule, thermosets are processed in torpedo-containing extruders. With thermosets, most of the curing reaction must occur in a heated pressure chamber. Pressures can approach several hundred bars. The rate of extrusion is lowest with thick-walled bodies. Tubes are extruded at rates of up to 10 m/min, films up to 150 m/min, and telephone-cable insulating material or fibers at up to 1000 m/min. In extrusion, the Barus effect (Section 11.3.1) and melt fracture (Section 7.6.1) may be observed. Tubes, films, ducts, cable insulation, and knot-free nets are produced by extrusion. 

Beam collimation and table movement together (i.e. pitch) determine the volume of tissue irradiated per gantry rotation, whereas section collimation determines the minimal slice (also known as section) thickness that can be reconstructed from an examination s raw data. That is, the narrowest selected reconstructed slice thickness available will equal the selected size of the detector elements (Dalrymple et al. 2005). Section collimation may also be referred to as (effective) detector (row) thickness. The term detector configuration merely couples together the value selected for the section collimation with the number of detector elements. For example 4 x 1.25 refers to a four- channel scanner acquiring four channels of data 1.25 mm thick. Similarly, 16 x 0.625 refers to 16 channels of data 0.625 mm thick obtained on a 16-channel scanner. From this information and the equation for pitch, it can be seen that detector configuration is numerically equal to the beam collimation (Rydberg et al. 2003 Saini 2004). 

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