Evaluation of emissions benefits of OBD-based repairs for potential application in a heavy-duty vehicle Inspection and Maintenance program
Yu JiangJiacheng YangYi TanSeungju YoonHung-Li ChangJohn CollinsHector MaldonadoMark CarlockNigel ClarkDavid L. McKainDavid R. CockerGeorgios KaravalakisKent C. JohnsonThomas D. Durbin
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Previous computations of low-temperature Rosseland and Planck mean opacities from Alexander & Ferguson are updated and expanded. The new computations include a more complete equation of state (EOS) with more grain species and updated optical constants. Grains are now explicitly included in thermal equilibrium in the EOS calculation, which allows for a much wider range of grain compositions to be accurately included than was previously the case. The inclusion of high-temperature condensates such as Al2O3 and CaTiO3 significantly affects the total opacity over a narrow range of temperatures before the appearance of the first silicate grains. The new opacity tables are tabulated for temperatures ranging from 30,000 to 500 K with gas densities from 10-4 to 10-19 g cm-3. Comparisons with previous Rosseland mean opacity calculations are discussed. At high temperatures, the agreement with OPAL and Opacity Project is quite good. Comparisons at lower temperatures are more divergent as a result of differences in molecular and grain physics included in different calculations. The computation of Planck mean opacities performed with the opacity sampling method is shown to require a very large number of opacity sampling wavelength points; previously published results obtained with fewer wavelength points are shown to be significantly in error. Methods for requesting or obtaining the new tables are provided.
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For ensuring safety of heavy duty vehicles running on long downhill sections, a model was built for the application of engine brake and service brake combination based on test results. A model of brake temperature rise for heavy duty vehicles running on long downhill sections was also constructed. For different braking modes, gear positions, speed and downhill slopes, brake temperature rising to 250°C was used as the index. Then simulation of brake temperature rise and downhill distance was researched. Simulation results illustrate that the combined braking of low gear and high speed should be adopted for heavy duty vehicles running on long downhill sections.
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Novel opacity calculations, which treat in detail the spectra of medium-Z ions [Rogers and Iglesias, Astrophys. J. Suppl. Ser. 79, 507 (1992)], produce results that are substantially different from opacity calculations extant in the literature. These new opacities provide solutions to a number of outstanding problems in astrophysics, thus providing an indirect validation of the theory. We report the results of an experiment measuring the photoabsorption in the spectral region from 50 to 120 eV of x-ray-heated iron which corroborate these new opacity calculations.
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The method of emission inspection for Heavy-duty diesel vehicles has been engine speed type Lug-down 3mode. This method could bring damage to decrepit vehicles under high speed and high load condition and it could not apply the driving pattern on the road. For these reasons, this study has started to create new emission inspection which is appropriate for Korea's road infrastructure. KD 147 would be applied to light-duty diesel vehicles from july 2010 after model operations. Therefore, this study has investigated new emission inspection system for heavy-duty diesel vehicles, except for light-duty diesel vehicles. In consideration of domestic conditions to meet the new load test method in this study, the Lug-down3 mode vehicle speed method was developed for the first time in korea.
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Hohlraum
National Ignition Facility
Thomson scattering
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Radiation transport through high-opacity materials can be described using the Rosseland mean opacity of the medium, which is dominated by low-opacity regions in the frequency-dependent opacity. By mixing gold and gadolinium, we can fill in low-opacity regions of one material with high-opacity regions of another material, resulting in a material with a Rosseland mean opacity $1.5\ifmmode\times\else\texttimes\fi{}$ higher than either of the constituents. For a given laser energy, this can raise the temperature of the laser heated hohlraums, or for a given desired temperature, require less laser energy.
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A method is described for measuring the opacity of anesthetic dental filling materials using a goniophotometer. Procedures are given for converting measured opacity values to those referred to a 70% reflectance background (C0.7 values) as required by existing specifications. The conversion is involved, and, since most available white surfaces have reflectance of about 80%, it is recommended that in future specifications opacity be recorded as C0.8 values. Opacity values for 28 materials are reported. It was found that the opacity of dental cement decreases for several days following preparation and that powder/liquid ratio has little effect, while pigmentation has a marked effect on opacity.
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