This paper reports on the observed behavior of coal particles during thermal decomposition. The data presented are the first from a study initiated to address both the physical and chemical behavior of pulverized coal from the time of initial heating through the evolution of soot particulate. In the present study, pulverized (high volatile bituminous) coal was injected through a slit centered in a methaneair flat flame burner, and high resolution holography was employed to record the evolution of volatiles and the structure of soot particulate. Volatiles were observed to evolve in a variety of shapes that range from individual jets to uniformly distributed clouds. Coal particle fragments and/or incipient soot nodules (∼ 3 micron) were found to be present within the volatile gases during the evolution. Further from the burner, stringlike soot particles approaching 1600 microns in length were observed. © 1981.

The spatial profile of fluid flow velocity in transparent glass conduits is measured using optical Doppler tomography (ODT). The flow velocity at any spatial location in the conduits is determined by measuring the Doppler shift of backscattered light from moving microspheres in the fluid. ODT is an accurate and inexpensive method for high resolution characterization of fluid flow velocity profile.

We describe a technique for measuring the instrument transfer function (ITF) of an interferometric microscope, allowing both characterization and data processing to increase the fidelity and effective resolution of the tool. The technique, based on test samples structured as two-dimensional (2D) binary pseudo-random arrays (BPRAs), employs the unique properties of the BPRA patterns in the spatial frequency domain. The inherent 2D power spectral density of the pattern has a deterministic white-noise-like character that allows direct determination of the ITF with uniform sensitivity over the entire spatial frequency range and field-of-view of an instrument. As such, the BPRA samples satisfy the characteristics of a test standard: Functionality, ease of specification and fabrication, reproducibility, and low sensitivity to manufacturing error. We discuss the results of the development and application of highly randomized (HR) BPRA test samples with elementary feature sizes in the range from 80 nm and up to 2.5 μm, optimized for the ITF characterization of interferometric microscopes broadly used for 2D optical surface profiling. The data acquisition and analysis procedures for different applications of the ITF calibration technique developed are also discussed.

This work reports on the development of a binary pseudo-random test sample optimized to calibrate the MTF of optical microscopes. The sample consists of a number of 1-D and 2-D patterns, with different minimum sizes of spatial artifacts from 300 nm to 2 microns. We describe the mathematical background, fabrication process, data acquisition and analysis procedure to return spatial frequency based instrument calibration. We show that the developed samples satisfy the characteristics of a test standard: functionality, ease of specification and fabrication, reproducibility, and low sensitivity to manufacturing error.