Use of FLACS during the TWA-800 Accident Investigation

PresentationThe TWA flight 800 accident occurred on July 17, 1996 just outside New York City shortly after take-off. The airplane desintegrated as a result of an “explosion” and 230 people were killed. The investigation concentrated on the possibility of a gas explosion in the Centre Wing Fuel Tank (CWT). The hypothesis was that the heating of fuel in the tank by the air conditioning system was the cause of the flammable vapor concentration (temperature above flash-point). The explosion investigation used laboratory experiments, scale-model tests, and numerical simulations to examine the explosion of Jet-A (aviation kerosene) mixtures with air under conditions simulating the center wing tank environment at the time of the accident. Work was carried out over a period of four years to determine the chemical and physical properties of Jet A, particularly the flammability limits, combustion behavior, and the propagation of flames through the compartmentalized structure of the center wing tank. The CFD tool FLACS was adapted and validated against scale-model experiments. The problem of quenching or flame extinction was identified as an issue and addressed through experiments and modeling. FLACS was then used in full-scale simulations to explore the effects of various parameters and assumptions, especially ignition locations within the tank. All of this information was integrated through a rule-based system to attempt to narrow down the number of plausible ignition locations that would be consistent with the observed damage as deduced from the recovered wreckage

Initial Flood Deposits of the Western North American Cordillera: California, Utah and Idaho

Discontinuous but widespread coherent packages (unbroken by major unconformities) of Neoproterozoic sedimentary strata, recognized by basal diamictite deposits (debris flows), outcrop throughout the western North American Cordillera. These phenomenal clastic packages, which represent high-energy sedimentary environments, overlie older sedimentary, metamorphic and igneous rocks, and underlie younger regionally widespread fossiliferous sandstone, carbonate and shale. The basal, high-energy debris flow deposits sporadically occur throughout the length of the western North American Cordillera and locally contain submarine volcanic extrusive and igneous intrusive rocks. Geological activity during the start of the Flood when, all the fountains of the great deep burst forth necessitates a record of geologic signatures or discontinuities on a grand scale. Explanation for these high-energy geologic events needs to proceed from a Biblical worldview supported by the empirical data contained within the rocks. High-energy catastrophic processes recorded: mechanical-erosional, timeage, tectonic, sedimentary, and paleontologic discontinuities in the western North American Cordillera. Clastic sedimentary rocks underlying the western Cordillera thicken remarkably while the same sediments thin towards the east and truncate with regional fossiliferous sandstones. Igneous activity and contemporaneous deposition across fault-bounded basins record tectonic discontinuities. The coarse to fine megasuccession found in the North American Cordillera characterize initial and early Flood deposits. Three rock units are considered: the Kingston Peak Formation in the Death Valley region of California, the Dutch Peak Formation in the Sheeprock Mountains in central Utah, and the Pocatello Formation in the vicinity of Pocatello, Idaho. These formations display abrupt thickening of sediments towards presumed fault-bounded basins, overlie older sedimentary, igneous or metamorphic rocks, and underlie thick successions of clastic rock with increasing megafossil content upwards. Additionally, some of the debris flows contain evidence of contemporaneous submarine volcanic activity. The high-energy debris flow deposits found in the Kingston Peak, Dutch Pea

Well-defined silica-supported olefin metathesis catalysts

Two triethoxysilyl-functionalized N-heterocyclic carbene ligands have been synthesized and used to prepare the corresponding second-generation ruthenium olefin metathesis catalysts. These complexes were then grafted onto silica gel, and the resulting materials were efficient heterogeneous catalysts for a number of metathesis reactions. The solid-supported catalysts were shown to be recyclable over a number of reaction cycles, and no detectable levels of ruthenium were observed in reaction filtrates (ruthenium concentration of filtrate <5 ppb)

Submarine Flow and Slide Deposits in the Kingston Peak Formation, Kingston Range, Mojave Desert, CA: Evidence for Catastrophic Initiation of Noah\u27s Flood

The case for a glacial origin for the upper Proterozoic Kingston Peak Formation is weak. Stratigraphic correlations and rock descriptions suggest a marine depositional environment for the entire formation. The Lower Sandstone Unit of the Kingston Peak Formation is best interpreted as an Antediluvian inner shelf deposit. It is underlain by other widespread shelf deposits, the Beck Spring Dolomite followed by the Crystal Spring Formation which rests on granitic gneiss. Thick accumulations of pUddingstones (called diamictite by many), interpreted as sandy and limy debris flows, overlap the shelf deposits. These, in turn, are overlain by rhythmically laid breccias and megabreccias interpreted as clast-supported debris flows. The debris was derived mainly from the underlying Beck Spring Dolomite and Crystal Spring Formation. At the start of the Flood large-scale catastrophic plate tectonics associated with the subduction zone to the west caused the pre-Flood sea floor to collapse. Sandy and limy debris flows moving at the rate of 15-30 m/s were instantly generated at the onset of massive local faulting associated with the event. A displacement of 950 m or more in some areas along the giant fault scarp converted the shelf into a 60° slope environment. This activity spawned seismic sea waves. Sheet flows of fluidized rock masses fell over the cataract and flowed across the basin at 50-100 m/s. In the deeper areas large scale slumping occurred as huge megaclasts or slabs hundreds of meters long slid downslope within a succession of high concentration turbidites. These catastrophic coarse clastic deposits of the middle and upper Kingston Peak Formation at the Kingston Range directly overly and crosscut into the Crystal Spring Formation and crystalline basement at nearby mountain ranges. This unconformity of extreme magnitude may correlate with the Great Unconformity and mark the base of the Sauk megasequence. After the Kingston Peak flow and slide deposits, widespread marine sediments, beginning with the Noonday Dolomite, began to be deposited as the oceans inundated the continents