4,694 research outputs found
Computer analysis of effects of altering jet fuel properties on refinery costs and yields
This study was undertaken to evaluate the adequacy of future U.S. jet fuel supplies, the potential for large increases in the cost of jet fuel, and to what extent a relaxation in jet fuel properties would remedy these potential problems. The results of the study indicate that refiners should be able to meet jet fuel output requirements in all regions of the country within the current Jet A specifications during the 1990-2010 period. The results also indicate that it will be more difficult to meet Jet A specifications on the West Coast, because the feedstock quality is worse and the required jet fuel yield (jet fuel/crude refined) is higher than in the East. The results show that jet fuel production costs could be reduced by relaxing fuel properties. Potential cost savings in the East (PADDs I-IV) through property relaxation were found to be about 1.3 cents/liter (5 cents/gallon) in January 1, 1981 dollars between 1990 and 2010. However, the savings from property relaxation were all obtained within the range of current Jet A specifications, so there is no financial incentive to relax Jet A fuel specifications in the East. In the West (PADD V) the potential cost savings from lowering fuel quality were considerably greater than in the East. Cost savings from 2.7 to 3.7 cents/liter (10-14 cents/gallon) were found. In contrast to the East, on the West Coast a significant part of the savings was obtained through relaxation of the current Jet A fuel specifications
Solvable Leibniz algebras with triangular nilradical
A classification exists for Lie algebras whose nilradical is the triangular
Lie algebra . We extend this result to a classification of all solvable
Leibniz algebras with nilradical . As an example we show the complete
classification of all Leibniz algebras whose nilradical is .Comment: arXiv admin note: text overlap with arXiv:1307.844
Migrancy and male sexuality on the South African gold mines
Paper presented at the Wits History Workshop: The Making of Class, 9-14 February, 198
A preliminary assessment of age at death determination using the nuclear weapons testing 14C activity of dentine and enamel
Calibration (using CALIBomb) of radiocarbon measurements made on the enamel of human teeth from people
born during the nuclear era typically produce 2 possible age ranges that potentially reflect the period of tooth formation. These
ranges correspond to periods before and after the 1963 atmospheric 14C maximum. Further measurements made on the
collagen component of the combined dentine and cementum from the roots of the same teeth enable the appropriate age range
to be selected. Using this range and the formation times for individual teeth, we estimated the year of birth of the individuals
and compared these to the known dates of birth. The results were relatively accurate and confirmed those of a previous study
by another research group. The present study demonstrates that it is possible to produce a good estimate of the year of birth
from a single tooth
A Case Study Analysis of the āLetter from Birmingham Jailā: Conceptualizing the Conscience of King through the Lens of Paulo Freire
The pedagogical qualities of Martin Kingās āLetter from Birmingham Jailā can be observed through the lens of Paulo Freire as his illustration of thematic universeās can be used as a framework to contextualize the conscience of King. King encountered obstacles, in his contemporary context, to his self-actualization that once cognitively subjugated were transformative to his being. Three questions are explored: What manifestations led to the writing of the āLetter from Birmingham Jailā? What were Kingās transformative actions? Will an answer to the first help make sense of the second? I endeavor to briefly examine the āLetter from Birmingham Jailā through the lens of Paulo Freire
INFERENCE OF SURFACE VELOCITIES FROM OBLIQUE TIME LAPSE PHOTOS AND TERRESTRIAL BASED LIDAR AT THE HELHEIM GLACIER
Using time dependent observations derived from terrestrial LiDAR and obliquetime-lapse imagery, we demonstrate that a Bayesian approach to glacial motion es-timation provides a concise way to incorporate multiple data products into a singlemotion estimation procedure effectively producing surface velocity estimates withan associated uncertainty. This approach brings both improved computational effi-ciency, and greater scalability across observational time-frames when compared toexisting methods. To gauge efficacy, we apply these methods to a set of observa-tions from the Helheim Glacier, a critical actor in contemporary mass loss trendsobserved in the Greenland Ice Sheet. We find that the Helheim glacier exhibitsa mean velocity of approximately 19mdā1 and discuss the implications of thesemethods as they pertain to ongoing efforts to characterize the Greenland Ice Sheetand its contributions to global mean sea level rise
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