Abstract: A method and apparatus for determining the size distribution of certain particles, of a particular composition, such as iron sulfide (pyrites), in a sample of host material, such as coal. Data representative of the amount of at least one predetermined elemental constituent of the particles is obtained for each of numerous similarly-sized subsamples of the sample. The "constituent amount" data for each subsample is sorted into bins, each representative of a respective constituent amount range in a series of constituent amount ranges. Respective scaler representations of the fraction of the constituent amounts, represented by each bin range, are provided to yield an approximate representation of the distribution function of the amounts of the constituent in the subsamples of the coal. Those scaler representations collectively may provide a histogram.

Abstract: New and improved method and apparatus for the correction of coincident errors attendant the automated detection and counting of mixed particles having detectable characteristics of different levels in particle counting applications wherein the detection of "dominant" particles under coincident particle conditions, renders undetectable the "dominated" particles, with resulting inaccuracy in the "dominated" particle count. Such inaccuracy is corrected by modifying the "dominated" particle count in accordance with the time duration of the signals which are generated attendant the detection of the "dominated" particles.

Abstract: A tandem arrangement of sensing zones is established by alternately arranged electrodes and dielectric plates, each sensing zone has a particle sensing aperture, through which microscopic particles in an electrolyte suspension pass and electric current flows. The apertures are aligned. This tandem sensing zone arrangement improves the signal-to-noise ratio of a particle analyzing apparatus in which it is employed.

Abstract: A particle analyzer wherein a flow of liquid suspension, having individually entrained particles, flows along a predetermined path; a center pair of electrodes are positioned on opposed sides of the predetermined path: the center electrodes are energized to provide an electrical sensing field therebetween, two pairs of outer electrodes are positioned so that one pair is on each side of the center electrodes; the outer electrodes are oriented and/or energized so that their electrical fields bulge outward in the direction of the sensing field of the center plates to narrow the width of the sensing field along the predetermined path. Additionally, the field between the center plates can be focused in additional directions and the sensing electrode arrangement can be implemented in a flow cell, with or without an aperture, or on the surface of a substrate.

Abstract: Apparatus for counting platelets and red blood cells in a whole blood sample includes an aperture type transducer. Alarm techniques are provided for indicating defects in the counting procedure due to excessive noise or red cell fragments, small (microcytic) red cells, and giant (macro) platelets.