Carbonaceous species tests

These factors combine to make impactors less precise and accurate than filters. Very few comparisons have been made between sizing impactors and those that have provided mixed results. The 1977 Environmental Protection Agency-Department of Energy Sampler Intercomparison included the Multi-Day Sampler, which performed well ( 15%) for fine aerosols such as sulfur, lead, and zinc (15). The 1986 Carbonaceous Species tests at Glendora, California, included the DRUM sampler. It performed well for sulfur ( 18%), as compared to the fine filter sampler (PM-2.5), but no other sizing impactor was available for comparison and no element other than sulfur was reported. DRUM versus filter comparisons were reported as part of the Southern California Air Quality Study of 1987 (2). Again, no other impactor was available for comparison, and the comparisons with filters were only fair (r2 0.7 r, linear correlation coefficient). 

Figure 1 Inlet and outlet gas concentrations Figure 2 Overall scheme of the two step obtained over Pt/Ce02 tested at 400°C by process over a catalyst combining a noble feeding sequentially a fixed bed reactor (4mm metal and a support able to store I.D.) with methane, then helium, then oxygen carbonaceous species [6]. For the present and so forth. case, M = Pt and support = ceria...

Although the first demonstration that amino acid racemization took place in fossils used mollusc shells (23), the application of this reaction in dating these materials has been extensively investigated only recently (19,20). Work on Mercenaria (19), Chione (20), and other species (24) has tested the application of racemization dating to fossil mollusc shells from geological contexts and Indian shell middens. These and other studies have shown that there are problems with amino acid racemization dating of carbonaceous fossils which are not encountered with bone. Reversible first-order racemization kinetics which are observed in bone... 

To put to test the above suggestion, we examined nanoporous carbonaceous sorbent D4609 in combination with rather concentrated mixtures of NaCl and HCl or NaOH taken in equal proportions. In the first salt/acid pair the species that determine the rates of movement of solute fronts are hydrated Na cation and CC anion with ionic radii of 3.58 and 3.32 A, respectively. The difference in their sizes is not too large, but obviously sufficient for a successfid separation. As illustrated by Fig. 12.6, the fronts of NaCl and HCl diverge by one-third of the total bed volume (A = 0.33) in both the forward and reverse experiments. Here, HCl behaves as a clearly... 

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