Monochromatic sorting

Fig. 6.4 Visible reflectance spectra for white rice. In this example, a blue band-pass filter would be used for monochromatic sorting.

Monochromatic sorting is based on the measurement of reflectance at a single isolated band of wavelengths. For optical sorting to be effective, there must be a distinct difference in reflectance within the selected waveband, between all the acceptable particles and all the reject particles (see Fig. 6.4). Removal of dark, rotten items from product like peanuts, or dried peas and removal of black peck from rice are typical applications of monochromatic sorting. 

Parboiled rice 90004 Focus - 128 channel, 4 gravity chute, monochromatic sorting machine Remove spotted, discoloured rice and foreign material (stones, glass, paddy, etc.) 5 to 10... 

Because radiation should be as monochromatic as possible in order to maximize the diffraction effect from atoms in a crystal, the continuous spectrum is either suppressed by selective filters, also illustrated in Figure 7.2, or a discrete wavelength of X ray is isolated with a monochromater of some sort. For most biological structure analyses in the laboratory where a sealed X-ray tube or a rotating anode source (see below) is employed, the anode is of pure copper or occasionally molybdenum. These two elements have strong, characteristic Ka peaks in their spectra at 0.154 nm (1.54 A) and 0.071 nm (0.71 A), respectively. These... 

When monochromatic radiation is incident on the specimen, it sends out diffracted beams at particular W angles. These beams enter the side window of the counter at particular points, causing pulse formation at those points. The times required for these pulses to travel to the end of the counter are converted to digital form, analyzed, and sorted by the MCA. The contents of the MCA memory are therefore number of pulses (counts) as a function of the position on the anode wire where the pulses originated (angle 26). A display of the contents of the MCA resembles the pattern recorded by a conventional diffractometer (Fig. 7-5). 

The various ionic states are conveniently studied by means of photoelectron q>ectros py. In a photoelectron spectrometer molecules of the sample are irradiated with monochromatic electromagnetic radiatkm and the ejected electrons are sorted in an electric field according to their kinetic energy. The number of electrons counted for a certain kinetic energy is recorded in counts per second (cps, c/s). 

In this experiment, the photocurrent (/ph) of the sample is measured versus time (chronoamperometry) with or without an applied bias. In this case, monochromatic light is used over the solar UV-VIS-NIR spectrum (300-1100 nm). Figure 7.1 shows the experimental setup, which consists of an illumination source with a monochromator and a set of filters for order sorting. A mechanical shutter to chop... 

The light beam emitted by the incandescent lamp or a metal vapour lamp (e.g. Hg or Cd vapour lamp) is "sorted by the spectral filter in such a way that it is virtually monochromatic. As such it passes through the cuvette containing the solution of the substance to be determined (after exchanging the sample cuvette for a blank-test cuvette containing pure solvent). After leaving the cuvette the residual light intensity I of the beam is converted to an electric current in the photoelectric cell... 

One of these checks derives directly from SVL fluorescence itself. In a number of areas, we can merely inquire if the structure in SVL fluorescence excited by monochromatic pumping of an absorption band in question is consistent with the emitting state predicted by the absorption analysis. An inquiry of this sort, for example, shows that the absorption bands assigned by GP to activity in Vg do not in fact involve Vg. This confirms the similar conclusion reached by CDM through their rotational band contour analysis. 

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