M. Jha
3 records found
1
Considering a flame has a three-dimensional structure, in this thesis, an optical combustion diagnostics technique of Computed Tomography of chemiluminescence (CTC) was applied to Bunsen burner flames using six CCD cameras. The cameras were arranged around the flame and a tomographic algorithm was used to reconstruct the three-dimensional structure of the flame. The technique was applied to turbulent 100% by volume fraction Dutch Natural Gas (DNG) flames at various Reynolds numbers representing stable, close to flashback, and flashback case. The reconstructed DNG flame results highlighted the capability of the CTC technique to offer valuable insights into the intricate features of the flame. Furthermore, these results not only indicated the possible location of the origin of the flashback within the structure of flame but also revealed specific features associated with events prior to the flashback. recognizing the potential of this technique, it was subsequently applied to a turbulent flame consisting of 50% hydrogen blended with 50% DNG. The reconstruction results offered insights into the fundamental structural differences between a flame consisting of 50% hydrogen and 50% DNG and a pure 100% DNG flame. The conclusions drawn from the visual assessments of the reconstruction results were further supported by the subsequent statistical analysis and the resulting cone angle values.
Commissioning studies of the CMS hadron calorimeter have identified sporadic uncharacteristic noise and a small number of malfunctioning calorimeter channels. Algorithms have been developed to identify and address these problems in the data. The methods have been tested on cosmic ray muon data, calorimeter noise data, and single beam data collected with CMS in 2008. The noise rejection algorithms can be applied to LHC collision data at the trigger level or in the offline analysis. The application of the algorithms at the trigger level is shown to remove 90% of noise events with fake missing transverse energy above 100 GeV, which is sufficient for the CMS physics trigger operation.
@enThe CMS Hadron Calorimeter in the barrel, endcap and forward regions is fully commissioned. Cosmic ray data were taken with and without magnetic field at the surface hall and after installation in the experimental hall, hundred meters underground. Various measurements were also performed during the few days of beam in the LHC in September 2008. Calibration parameters were extracted, and the energy response of the HCAL determined from test beam data has been checked.
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