Anti-C3 monoclonal antibody, clone H13

We have used the single-pulse shock tube technique with postshock GC/MS product analysis to investigate the mechanism and kinetics of the unimolecular decomposition of isopropanol, a potential biofuel, and of its reaction with H atoms at 918-1212 K and 183-484 kPa. Experiments employed dilute mixtures in argon of isopropanol, a radical scavenger, and, for H-atom studies, two different thermal precursors of H. Without an added H source, isopropanol decomposes in our studies predominantly by molecular dehydration. Added H atoms significantly augment decomposition, mainly by abstraction of the tertiary and primary hydrogens, reactions that, respectively, lead to acetone and propene as stable organic products. Traces of acetaldehyde were observed in some experiments above approximate to 1100 K and establish branching limits for minor decomposition pathways. To quantitatively account for secondary chemistry and optimize rate constants of interest, we employed the method of uncertainty minimization using polynomial chaos expansions (MUM-PCE) to carry out a unified analysis of all datasets using a chemical model-based originally on JetSurF 2.0. We find:k(isopropanol -> propene + H2O) = 10((13.87 +/- 0.69))exp(-(33 099 +/- 979) K/T) s(-1)at 979-1212 K and 286-484 kPa, with a factor of two uncertainty (2 sigma), including systematic errors. For H atom reactions, optimization yields:k(H + isopropanol -> H-2+p-C3H6OH)( )= 10((6.25 +/- 0.42))T(2.54)exp(-(3993 +/- 1028) K /T) cm(3)mol(-1)s(-1)andk(H + isopropanol -> H-2+t-C3H6OH)( )= 10((5.83 +/- 0.37))T(2.40)exp(-(1507 +/- 957) K /T) cm(3)mol(-1)s(-1)at 918-1142 K and 183-323 kPa. We compare our measured rate constants with estimates used in current combustion models and discuss how hydrocarbon functionalization with an OH group affects H abstraction rates.

The Northwest Atlantic is a region of strong temperature gradients and hence is a favourable location for wintertime cyclone intensification co-located with the storm track. The temperature gradient is associated with both the sea surface temperature front along the Gulf Stream and the land-sea contrast. To understand the respective influences of the sea surface temperature (SST) front and land-sea contrast in the Gulf Stream region, as well as the role of upper-level forcing on cyclone development, we track individual cyclones and categorise them depending on their propagation relative to the SST front. We concentrate on cyclones staying either on the cold (C1) or warm (C2) side of the SST front, and on cyclones that cross the SST front from the warm to the cold side (C3). Comparing these categories, we find that the land-sea contrast is more important for supplying baroclinicity to cyclones in C1, while the strong low-level baroclinicity in C3 is also partially attributable to the SST front. The propagation of cyclones in C1 and C3 near the left exit region of the North Atlantic jet explains the higher intensification and precipitation.