The Federal Aviation Administration/Massachusetts Institute of Technology (FAA/MIT) Lincoln Laboratory Doppler weather radar program

The program focuses on providing real-time information on hazardous aviation weather to end users such as air traffic control and pilots. Existing systems will soon be replaced by a Next Generation Weather Radar (NEXRAD), which will be concerned with detecting such hazards as heavy rain and hail, turbulence, low-altitude wind shear, and mesocyclones and tornadoes. Other systems in process are the Central Weather Processor (CWP), and the terminal Doppler weather radar (TDWR). Weather measurements near Memphis are central to ongoing work, especially in the area of microbursts and wind shear

Depositional History of the Eocene Chumstick formation - Implications of Tectonic Partitioning for the History of the Leavenworth and Entiat-Eagle Creek Fault Systems, Washington

The Chumstick basin opened as an extensional half-graben prior to 51 Ma, and was subsequently modified by two episodes of tectonic partitioning of drainage prior to basin deformation. Initially, westward flowing fluvial systems formed a unified depositional system with the Swauk basin. Tectonic partitioning of drainage at 51-49 Ma and at 44-42 Ma was controlled by localized uplift on the Leavenworth (LFZ), Eagle Creek (ECFZ), and Entiat (EFZ) fault zones and led in each instance to the truncation of regional depositional systems, modification and reversal of paleoflow, and internal drainage. Relief on the LFZ at 51-49 Ma may be the result of isostatic uplift of the extensional footwall, producing the Swauk and Chumstick basins as a pair of west facing half grabens. The earliest convincing evidence for the onset of oblique slip in the region is at about 48 Ma (folding in the Swauk basin) or about 44-42 Ma (probable transpressive uplift at left-stepping bends of the LFZ, development of a transtensional step-over basin between the ECFZ and EFZ, horsetail splays in the ECFZ, and possible flower structures in the LFZ and ECFZ in the Chumstick basin). Each episode of tectonic partitioning was followed by proximal onlap and overtopping of fault zones, to reestablish regional flow systems. The Chumstick Formation was deformed by dextral transpression between 37-34 Ma, and is unconformably overlain by the Oligocene Wenatchee Formation. The Chumstick basin is an example of an extensional basin modified by subsequent strike-slip tectonics, thus caution should be used in applying idealized basin models

Fluid Dynamics: Representations of Water in Music

Water has remained a subject of all kinds of musical works since at least the middle ages. These musical works lack the concrete representational capacity of paintings, photographs, and films, relying instead on more abstract metaphorical constructs to convey water imagery. Current scholarship on water music typically centers on Romantic and Impressionist works and does not examine the process of signification by which musical signs portray water. The principal goal of this study is to determine how musical devices convey specific aspects of bodies of water and how such devices interact and contribute to musical depictions of streams, rivers, lakes, and oceans. I find that evocations of motion in the form of waves and flow are especially important to portrayals of water; furthermore, music depicting motion can combine with devices evoking water’s other characteristics to create detailed, multifarious depictions. I give special attention to John Luther Adams’s water compositions, which are notable for their thorough depictions of bodies of water and represent a relatively new phenomenon: the focused musical depiction

Fluctuation-Induced Transitions in a Bistable Surface Reaction: Catalytic CO Oxidation on a Pt Field Emitter Tip

Fluctuations which arise in catalytic CO oxidation on a Pt field emitter tip have been studied with field electron microscopy as the imaging method. Fluctuation-driven transitions between the active and the inactive branch of the reaction are found to occur sufficiently close to the bifurcation point, terminating the bistable range. The experimental results are modeled with Monte Carlo simulations of a lattice-gas reaction model incorporating rapid CO diffusion

Subsurface Facies Analysis of the Late Cambrian Mt. Simon Sandstone in Western Ohio (Midcontinent North America)

The Cambrian Mt. Simon Sandstone (MSS) is a possible unconventional gas reservoir in the Illinois, Michigan, and Appalachian Basins, but comparatively little is known about the unit. This study used core and well logs from two deep exploratory wells to interpret the depositional environment of the MSS under western Ohio, where the MSS is about 120 m thick and found 1060 m below ground surface. In western Ohio, the MSS unconformably overlies the Precambrian Middle Run Formation, is conformably overlain by the Cambrian Eau Claire Formation, and has a distinctive gamma-ray log-signature. In well DGS-2627, the MSS consists of tan, friable, moderately sorted, rounded, coarse- to very coarse-grained siliceous quartz arenite with minor heterolithic sandstone-mudstone couplets (rhythmites) and quartz granule conglomerate. Features indicative of tidally-influenced, shallow marine settings include tidal rhythmites, lenticular-, flaser-, and wavy-bedding, herringbone cross-bedding, mud-drapes, tidal bundles, reactivation surfaces, intraclasts, and bioturbation. The unit generally coarsens- and thickens-upward, and is interpreted as migration of a tidally-influenced transgressive barrier sequence. A subsurface facies model for the MSS is developed by interpreting geophysical logs and cores from DGS-2627l, and this model is semi-quantitatively tested by first interpreting well BP-4 using geophysical logs alone, then confirming the results using core

Anisotropy in Nucleation and Growth of Two-Dimensional Islands during Homoepitaxy on Hex Reconstructed Au(100)

We present results of a comprehensive scanning tunneling microscopy study of the nucleation and growth of Au islands on Au(100). It is shown that the reconstruction of the substrate produces strong anisotropic effects. Rate equation analysis of the experimental flux and temperature dependence of the island density suggests: (i) a critical size of i=3 for T=315−380 K, but i\u3e3 above 400 K; and (ii) strongly anisotropic diffusion, preferentially parallel to the reconstruction rows (activation energy ∼0.2 eV). We comment on energetic and kinetic aspects of the observed island shape anisotropy