Evaluation detection, light sensors

Using the new light-reflecting type of deterioration sensor to accurately detect the concentration of finer insolubles in the oil enables more precise evaluation of oil deterioration. The basic elements of this construction are the light emitting element, the prism, and the light receiving element. There is a correlation between the increase in concentration of insolubles separated out at a speed of 20,000 G and sensor output (Tomita et ah, 1995). 

Particle counters also show promise for process control and performance evaluation, particularly in low-turbidity waters. Applications include more accurate evaluation of pilot plant studies and more sensitive control of particulate separation processes. However, when the power-law coefficient, p, is greater than 3, submicron particles, which escape detection with available counters, may control the magnitude of the total surface area concentration and the light-scattering properties of the particulate. It is likely that accurate process control and monitoring of solids/liquid separation processes will require both turbidimetric and particle size distribution measurements. Particle counting appears most promising as a feedback control sensor. 

A sensor for nitric oxide was constructed utilizing multiwaUed carbon nanotubes that were previously modified with ethylenediamine and sonicated in a solution containing Co -TSPP. Drop cast electrodes were prepared and characterized by field-emission transmission electron microscopy, X-ray photoelectron spectroscopy and by electrochemical techniques [220]. Cyclic voltammetry, electrochemical impedance, and chronoamperometry were utilized to evaluate the electrocatalytic activity of the hybrid sensor that exhibited linear response in the 6.6 x 10 to 1.3 X 10 mol L range, with a detection limit of 6.6 x 10 mol L. Electrodes composed of porphyrins, platinum nanowires, and Nafion were proposed for photocatalytic reduction of water [221]. After an extensive search for optimization of each component and under the best conditions (—350 mV and visible light irradiation) a detectable amount of hydrogen was produced, but Nafion can diminish the diffusion of ions to the porphyrin active sites. 

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