Coil Design Considerations

It is possible, however, to increase considerably the depth penetration and the percentage of electric field intensity in deep brain regions, relative to the maximal field at the cortex. The next section outlines the construction principles for efficient deep brain stimulation, and the following sections demonstrates several examples of TMS coils designed to accomplish this goal. 

As shown in this section, LC/NMR has been used successfully in various field of analytical chemistry. Further optimizations of the technique are, however, still awaited, especially on sensitivity issues. Very recently impressive progress, particularly with the introduction of liquid helium cooled cryoprobes and flow probes solenoid coils designs, has already improved considerably the detection limits. 

Cohen L.G., Roth B.J., Nilsson 1., et al. Effects of coil design on delivery of focal magnetic stimulation. Technical considerations. Elearoencephal. Clin. Neurophysiol. 1990 75 350-357. 

Cracking reactions are endothermic, 1.6—2.8 MJ/kg (700—1200 BTU/lb) of hydrocarbon converted, with heat supplied by firing fuel gas and/or fuel oil in side-wall or floor burners. Side-wall burners usually give uniform heat distribution, but the capacity of each burner is limited (0.1—1 MW) and hence 40 to 200 burners are required in a single furnace. With modem floor burners, also called hearth burners, uniform heat flux distribution can be obtained for coils as high as 10 m, and these are extensively used in newer designs. The capacity of these burners vary considerably (1—10 MW), and hence only a few burners are required. The selection of burners depends on the type of fuel (gas and/or liquid), source of combustion air (ambient, preheated, or gas turbine exhaust), and required NO levels. 

Afurther consideration maybe the possibility of reducing ice buildup on the evaporator, whether this is in the form of frost on fins or ice on the coils of a liquid chilling coil. Where temperatures close to freezing point are required, it may be an advantage to design with an evaporator temperature high enough to avoid frost or ice -either for safety or to simplify the defrost method. 

A device described by Sawyer and Dixon [13] was used for the determination of alcohol and acid in beer and stout. Attempts to improve the reliability of this method and to improve the signaTto-noise characteristics of the measurements prompted a critical design described by Lidzey et al. [14]. This unit overcomes many of the fluctuations in results observed with use of the first unit in this a number of possible sources of surging were indicated and these were not controlled owing to the varying conditions in the coil. In addition, the separation of the waste involatile material from the volatile phase took place outside the heated flask distillation unit. Air bubbles present in the segmented stream were also responsible for considerable surging. 

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