Optical methods, especially those that rely on passive emission, provide a simple and non-intrusive means to characterize combustion; however, in the presence of hot solid particles – particularly soot – chemiluminescent emission can be obscured by blackbody radiation.
Analysis of literature data published in the last few years leads to the conclusion that in the process of assessment of emission flux of organic compounds emitted from different types of equipment and finishing materials, new types of devices, among which small-scale passive emission chambers for the performance of in-situ research are designed and applied on a larger scale.
Specifically, numerical simulations were performed to study the correlation between passive neutron emission rate of an irradiated pebble and its burnup level, the detectability of passive neutron emission from an irradiated fuel pebble by commonly used neutron detectors, and these detectors' abilities to discriminate gamma interference.
Two linear arrays were designed and fabricated for passive gamma emission tomography of spent fuel rod assemblies in the water pools of nuclear power plants.
The overall conclusion is that there is an acceptable correlation between burnup and passive neutron emission rate of an irradiated pebble at high-burnup levels; and if the neutron detection system is well designed, passive neutron counting can be used to provide an on-line, go/no-go decision on fuel disposition on a pebble-by-pebble basis for pebble bed reactors.
For material emissions passive sampling was chosen as it represents an interesting means for field investigations requiring a large number of sampling points.
The specimens undergoing corrosion were simultaneously monitored by acoustic emission (passive) and ultrasonic guided wave (active) techniques.
In passive absorption-re-emission ALFs, a high-pass filter blocks all low-energy incoming light.
This review highlights the use of passive measurement of acoustic emissions created by a process as a potentially non-invasive, real-time monitoring technique to be used in process control.
In contrast, our CBPR framework resulted in the targeting of compressor stations for passive sampling, where diesel emissions likely account for the higher levels that we found.
