Stereoscopic pyrometer for char combustion characterization.

For many pulverized fuels, especially coal and biomass, char combustion is the time determining step. Based on intensified ICCD cameras, a novel setup has been developed to study pulverized fuel combustion, mainly in a laminar flow reactor. For char burning characterization, the typical measurement parameters are particle temperature, size, and velocity.

Determination of char combustion kinetics parameters: comparison of point detector and imaging-based particle-sizing pyrometry.

In this study, the char burnout characteristics of two German coals (a lignite and a high-volatile bituminous coal) were investigated using two different experimental configurations and optical techniques in two distinct laboratories for measurement of temperature and size of burning particles. The optical diagnostic hardware is quite different in the two systems, but both perform two-color pyrometry and optical sizing measurements on individual particles burning in isolation from each other in high-temperature laminar flows to characterize the char consumption kinetics. The performance of the specialized systems is compared for two different combustion atmospheres (with 6.

DBR and DFB lasers in neodymium- and ytterbium-doped photothermorefractive glasses.

The first demonstration, to the best of our knowledge, of distributed Bragg reflector (DBR) and monolithic distributed feedback (DFB) lasers in photothermorefractive glass doped with rare-earth ions is reported. The lasers were produced by incorporation of the volume Bragg gratings into the laser gain elements. A monolithic single-frequency solid-state laser with a linewidth of 250 kHz and output power of 150 mW at 1066 nm is demonstrated.

Single-frequency-mode Q-switched Nd:YAG and Er:glass lasers controlled by volume Bragg gratings.

This paper presents the results of experimental studies on Q-switched flash-lamp pumped Nd:YAG and Er:glass lasers with resonators formed by volume Bragg gratings. This novel design results in single-frequency mode operation with millijoules pulse energy. The mode selection is performed only by volume Bragg gratings that dramatically simplifies laser design.