83 research outputs found
NMR and GC/MS investigation of the saturate and distillate fractions from the Cerro Negro heavy petroleum crude
Six fractions of the Cerro Negro heavy petroleum crude have been evaluated using nuclear magnetic resonance spectroscopy (NMR) and gas chromatography/mass spectrometry (GC/MS). The fractions include four saturated hydrocarbon distillate fractions distilling above 200/sup 0/C (200 to 425/sup 0/C (392 to 797/sup 0/F), 425 to 550/sup 0/C (797 to 1022/sup 0/F), 550 to 700/sup 0/C (1022 to 1292/sup 0/F), and >700/sup 0/C (>1292/sup 0/F)) and two distillate subfractions designated as <200/sup 0/C and >200/sup 0/C. The >700/sup 0/C and 550 to 700/sup 0/C saturated hydrocarbon fractions are not suited for analyses by combined GC/MS because their distillation ranges are higher than the upper limit of material that will elute from the gas chromatographic column. The /sup 1/H and /sup 13/C NMR spectral data for the 550 to 700/sup 0/C and >700/sup 0/C fractions indicate that normal and branched alkanes with an average carbon chainlength of C/sub 10/ are present but must be bonded to a larger molecular moiety based upon mass spectral evidence and boiling point considerations. Normal and branched alkanes were not detected in either 200 to 425/sup 0/C or 425 to 550/sup 0/C samples at concentrations of 0.01% by weight. NMR data for the 200 to 425/sup 0/C fraction give no indication of normal alkanes with C chainlengths >9. Branched alkanes possibly of the isoprenoid-like structure are present. The average molecular structural representation is an alkyl-substituted dicyclic alkane. Average molecular structural representation for the 425 to 550/sup 0/C fraction is also an alkyl-substituted dicyclic alkane. However, at least one of the alkyl substituents has a chainlength >10. Both normal and branched alkanes of C/sub 7-12/ were detected in the <200/sup 0/C subfraction. Alkanes of C/sub 12-31/ were in the >200/sup 0/C sample. /sup 1/H and /sup 13/C spectra for both subfractions indicate similar chemical composition. 12 refs., 6 figs., 8 tabs
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Evaluation of coal pretreatment prior to co-processing
The Western Research Institute is currently developing a mild gasification process for the recovery of a stabilized char product for use as a fuel. A liquid product of limited value is produced during the mild gasification process that may be suited as a co-processing vehicle for coal-oil co-processing. Research was conducted to evaluate co-processing of this mild gasification liquid with coal. The two major areas of research discussed in this report are: (1) coal pretreatment with a coal-derived liquid to induce coal swelling and promote catalyst dispersion and (2) co-processing coal that has been thermally pretreated in the presence of the mild gasification liquid. The results of the investigation to evaluate co-processing of coal that has been thermally pretreated in the presence of the mild gasification liquid indicate that the thermal pretreatment adversely affected the coal-oil co-processing under hydrogen pressure. Thermally pretreated coals co-processed under a hydrogen atmosphere and without benefit of catalyst exhibited about 86 wt % conversion as compared to 96 wt % for coal that was only thermally dried. The addition of the iron pentacarbonyl catalyst precursor to the thermally pretreated coals did improve the conversion to near that of the dried coal. Results from analysis of the product obtained from co-processing the Illinois No. 6 coal showed it was upgraded in terms of oxygen content and hydrogen to carbon atomic ratio when compared to the mild gasification liquid
Charge-state dependence of K
Article discussing research on the charge-state dependence of K-shell x-ray production in aluminum by 2-12-MeV carbon ions
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Evaluation of coal pretreatment prior to co-processing
The Western Research Institute is currently developing a mild gasification process for the recovery of a stabilized char product for use as a fuel. A liquid product of limited value is produced during the mild gasification process that may be suited as a co-processing vehicle for coal-oil co-processing. Research was conducted to evaluate co-processing of this mild gasification liquid with coal. The two major areas of research discussed in this report are: (1) coal pretreatment with a coal-derived liquid to induce coal swelling and promote catalyst dispersion and (2) co-processing coal that has been thermally pretreated in the presence of the mild gasification liquid. The results of the investigation to evaluate co-processing of coal that has been thermally pretreated in the presence of the mild gasification liquid indicate that the thermal pretreatment adversely affected the coal-oil co-processing under hydrogen pressure. Thermally pretreated coals co-processed under a hydrogen atmosphere and without benefit of catalyst exhibited about 86 wt % conversion as compared to 96 wt % for coal that was only thermally dried. The addition of the iron pentacarbonyl catalyst precursor to the thermally pretreated coals did improve the conversion to near that of the dried coal. Results from analysis of the product obtained from co-processing the Illinois No. 6 coal showed it was upgraded in terms of oxygen content and hydrogen to carbon atomic ratio when compared to the mild gasification liquid
Dual sample injection for gas chromatographic determination of sulfur species with flame photometric detection
The ecology and evolution of autotomy
Autotomy, the self-induced loss of a body part, occurs throughout Animalia. A lizard dropping its tail to escape predation is an iconic example, however, autotomy occurs in a diversity of other organisms. Octopuses can release their arms, crabs can drop their claws, and bugs can amputate their legs. The diversity of organisms that can autotomize body parts has led to a wealth of research and several taxonomically focused reviews. These reviews have played a crucial role in advancing our understanding of autotomy within their respective groups. However, because of their taxonomic focus, these reviews are constrained in their ability to enhance our understanding of autotomy. Here, we aim to synthesize research on the ecology and evolution of autotomy throughout Animalia, building a unified framework on which future studies can expand. We found that the ability to drop an appendage has evolved multiple times throughout Animalia and that once autotomy has evolved, selection appears to act on the removable appendage to increase the efficacy and/or efficiency of autotomy. This could explain why some autotomizable body parts are so elaborate (e.g. brightly coloured). We also show that there are multiple benefits, and variable costs, associated with autotomy. Given this variation, we generate an economic theory of autotomy (modified from the economic theory of escape) which makes predictions about when an individual should resort to autotomy. Finally, we show that the loss of an autotomizable appendage can have numerous consequences on population and community dynamics. By taking this broad taxonomic approach, we identified patterns of autotomy that transcend specific lineages and highlight clear directions for future research
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