Optimum spectrum size

Taking into account peak area measurement uncertainty, and the need for a reasonable number of channels within a peak (to facilitate peak searches and fitting), it would seem that spectrum sizes of 4096 and 8192 channels would be optimum. With current detectors and spectrum analysis software, there seems little point in seeking larger spectrum sizes. 

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From the point of view of peak area uncertainty, the optimum spectrum size is 4096-8192 channels, depending upon the gamma-ray energy to be measured. 

It is first necessary to decide on the energy range required and from that the appropriate conversion gain (i.e. spectrum size). In Chapter 4, Section 4.6.8, it was explained that the optimum spectrum size is a balance between sufficient channels within the peaks of interest to aid computer deconvolution of peaks, bnt not so many that the statistical uncertainty on each channel snffers. The relationship in Equation (11.1) was snggested ... 

Selecting the optimum process encompasses a broad spectrum of possibilities (shape, size, material used, quantity, tolerance, time schedule, cost, etc.). There are designs when only one process can be used but there can be applications where different processes can be used. Each process, like each material of construction have their capabil-... 

If reduced Fe powder was added to the preceding solution at an optimum pH of 6-7, magnetite (Fe304) was deposited onto Si (100) or k-AIiOb at ca. 140°C over several hours [24]. No other phase was found in the XRD spectrum. It was suggested that the Fe304 formed by reaction between Fe(OH)3 (presumably formed by hydrolysis of the ferric nitrate) and Fe(OH)2 formed by hydrothermal oxidation of the Fe powder. Particle sizes of 150 mn (on AI2O3) and 50 mn (on Si) were measured by SEM. 

Figure 8.7 shows the droplet size spectra produced by nozzles in the study by Thornhill et al. (1995). They achieved lowest contamination by controlling pressure at 100 kPa, which, like the newer low-drift nozzles such the Turbo Teejet , produce larger spectra than standard flat fan atomisers. However, these settings simply shift the droplet size spectra out of the size range known to be most efficient for pesticides (e.g. Matthews, 1992 Knoche, 1994). The only way to reduce drift and maintain efficient dose transfer is to narrow the droplet spectrum with the optimum range illustrated using nozzles such as the Herbi rotary atomiser. 

Because high quality, low cost, and optimum performance are required for spray equipment, improved analytical and experimental tools are indispensable for increasing productivity in many competitive industries. In most instances, it is no longer adequate to characterize a spray solely on the basis of flow rate and spray pattern. Information on droplet size, velocity, volume flux, and number density is often needed and can be determined using advanced laser diagnostic techniques. These improvements have benefited a wide spectrum of consumer and specialized industrial products. 

A spectrum of particle sizes ensures optimum packing density. Interstices between individual particles can be filled with finer particles that prevent the penetration of binder. Both the manufacturer and user try to ensure that a specified product always has the same particle size distribution. 

Choosing the optimum process encompasses a broad spectrum of possibilities. In some situations only one process can be used, but generally there are options. Influencing the process selection are quantity, size, thickness, tolerances, type of material, and performance requirements (Table 7-2). Regarding tolerances, as mentioned in other chapters, resins with fillers and/ or reinforcements generally are far more stable in meeting tight tolerances. (In fact, the TSs, whether unreinforced or reinforced, are more dimensionally stable than other resins.)... 

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