Mehta, AK
1992
Examination of Ash Deposition in Full-, Pilot-, and Bench-Scale Testing
Zygarlicke, C.J.; Benson, S.A.; Borio, R.W. and Mehta, A.K.
Electric Power Research Institute Conference on Coal Quality, San Diego, CA, August 1992. Funded by US Department of Energy, Electric Power Research Institute and ABB-Combustion Engineering.
Ash deposition during pulverized coal combustion was studied in full-, pilot-, and bench-scale systems. Ash deposits were produced from two high-volatile bituminous coals at 1) the Mississippi Power Company Watson Unit 4 utility boiler, 2) the ABB-Combustion Engineering Fireside Performance Test Facility (FPTF), and 3) The Energy & Environmental Research Center (EERC) optical access drop-tube furnace. The chemical and physical characteristics of the slagging and fouling deposits produced in the three systems were examined to determine the components that were responsible for deposit growth and strength development. Similar mineral and amorphous phases, elemental chemistries, and liquid-phase viscosities were observed for full-and bench-scale deposits generate under similar combustion conditions. Although the two test coals were very similar in composition, they performed differently, as evidenced in all three combustion regimes. The "Baseline" coal, a bituminous coal, which is also the baseline coal diet at Watson Unit 4, produced less severe slagging and fouling deposits than the alternate coal which was the "Alternate" a bituminous coal. All three combustion regimes produced data such as quantity and composition of low-viscosity silicate liquid phases, deposit adhesion or bonding strength, deposit crushing strength, and heat flux/heat transfer data which supported the conclusion that the Alternate deposits were more difficult to remove and caused greater impedance to heat transfer.
Volume Seedlings
Cohen, M.F.; Painter, J.S.; Mehta, A.K. and Ma, K.-L.
ACM Symposium on Interactive 3-D Graphics, Cambridge, MA, March 1992. Funded by International Business Machines and ACERC.
Recent advances in software and hardware technology have made direct ray-traced volume rendering of 3-d scalar data a feasible and effective method for imaging of the data's contents. The time costs of these rendering techniques still no not permit full interaction with the data, and all of the parameters affecting the resulting images. This paper presents a set of real-time interaction techniques that have been developed to permit exploration of a volume data set. Within the limitation of a static viewpoint, the user is able to interactively alter the position and shape of an area of interest, and modify local viewing parameters. A run length encoded cache of volume rendering samples provides the means to rerender the volume at interactive rates. The use locates and plants "seeds" in areas of interest through the use of data slicing and isosurface techniques. Image processing techniques applied to volumes (i.e. volume processing), can then automatically form regions of interest that in turn modify the rendering parameters. This "region growing" of "seedlings" incrementally alters the image in real-time providing further visual cues concerning the contents of the data. These tools allow interactive exploration of internal structures in the data that may be obscured by other imaging algorithms. Magnetic Resonance Angiography (MRA) provides a driving application for this technology. Results from preliminary studies of MRA data are included.
Mehta, AK
1992
Examination of Ash Deposition in Full-, Pilot-, and Bench-Scale Testing
Zygarlicke, C.J.; Benson, S.A.; Borio, R.W. and Mehta, A.K.
Electric Power Research Institute Conference on Coal Quality, San Diego, CA, August 1992. Funded by US Department of Energy, Electric Power Research Institute and ABB-Combustion Engineering.
Ash deposition during pulverized coal combustion was studied in full-, pilot-, and bench-scale systems. Ash deposits were produced from two high-volatile bituminous coals at 1) the Mississippi Power Company Watson Unit 4 utility boiler, 2) the ABB-Combustion Engineering Fireside Performance Test Facility (FPTF), and 3) The Energy & Environmental Research Center (EERC) optical access drop-tube furnace. The chemical and physical characteristics of the slagging and fouling deposits produced in the three systems were examined to determine the components that were responsible for deposit growth and strength development. Similar mineral and amorphous phases, elemental chemistries, and liquid-phase viscosities were observed for full-and bench-scale deposits generate under similar combustion conditions. Although the two test coals were very similar in composition, they performed differently, as evidenced in all three combustion regimes. The "Baseline" coal, a bituminous coal, which is also the baseline coal diet at Watson Unit 4, produced less severe slagging and fouling deposits than the alternate coal which was the "Alternate" a bituminous coal. All three combustion regimes produced data such as quantity and composition of low-viscosity silicate liquid phases, deposit adhesion or bonding strength, deposit crushing strength, and heat flux/heat transfer data which supported the conclusion that the Alternate deposits were more difficult to remove and caused greater impedance to heat transfer.
Volume Seedlings
Cohen, M.F.; Painter, J.S.; Mehta, A.K. and Ma, K.-L.
ACM Symposium on Interactive 3-D Graphics, Cambridge, MA, March 1992. Funded by International Business Machines and ACERC.
Recent advances in software and hardware technology have made direct ray-traced volume rendering of 3-d scalar data a feasible and effective method for imaging of the data's contents. The time costs of these rendering techniques still no not permit full interaction with the data, and all of the parameters affecting the resulting images. This paper presents a set of real-time interaction techniques that have been developed to permit exploration of a volume data set. Within the limitation of a static viewpoint, the user is able to interactively alter the position and shape of an area of interest, and modify local viewing parameters. A run length encoded cache of volume rendering samples provides the means to rerender the volume at interactive rates. The use locates and plants "seeds" in areas of interest through the use of data slicing and isosurface techniques. Image processing techniques applied to volumes (i.e. volume processing), can then automatically form regions of interest that in turn modify the rendering parameters. This "region growing" of "seedlings" incrementally alters the image in real-time providing further visual cues concerning the contents of the data. These tools allow interactive exploration of internal structures in the data that may be obscured by other imaging algorithms. Magnetic Resonance Angiography (MRA) provides a driving application for this technology. Results from preliminary studies of MRA data are included.