Feasibility of JP-8 to Jet a Fuel Conversion at U. S. Military Facilities

In FY06, The Department of Defense (DoD) military grade jet fuel expenditures eclipsed $6.6 billion dollars. In a search for more cost effective options, the Office of the Secretary of Defense Comptroller recently expressed interest in the quantity of commercial Jet A fuel that the United States Transportation Command uses in lieu of military grade JP-8. In accordance with AFSO 21 and LEAN concepts, this research examines the technical feasibility and opportunity for cost avoidance of a conversion from JP-8 to Jet A at six Northwestern United States military installations. The technical feasibility analysis examines the chemical likeness of JP-8 and Jet A and identifies any aircraft or equipment that may impede a complete conversion. Accordingly, the opportunity for cost avoidance is considered through an analysis of military and commercial grade jet fuel influenced by West Coast refinery prices. The results show no technical barriers to a complete conversion, but there is no opportunity for cost avoidance

Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies

Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfv\'en waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, $\alpha=2$ as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed $>$600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: pre-flare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that $\alpha = 1.63 \pm 0.03$. This is below the critical threshold, suggesting that Alfv\'en waves are an important driver of coronal heating.Comment: 1,002 authors, 14 pages, 4 figures, 3 tables, published by The Astrophysical Journal on 2023-05-09, volume 948, page 7