IDA: An Architecture for an Intelligent Design Assistant for Assessing the Inspectability of Structures from a Description of Their Geometry

A program in integrated design, NDE, and the manufacturing sciences at the Center for Nondestructive Evaluation is developing a system that assesses the inspectability and reliability of mechanical structures from a description of their geometry, materials, and performance requirements. Part of this effort involves using techniques of artificial intelligence (AI) to integrate the various components. An Intelligent Design Assistant (IDA) couples the design team to CAD, stress, inspectability and reliability models and provides expert advice on how to improve the performance and reliability of the manufactured part

Lunar Seismometer and Burial System

Beginning in 1969, Apollo successfully deployed a long-lived network of seismometers on the Moon. Seismic studies provide definitive knowledge of internal planetary structure, and analysis of the Apollo seismic data has contributed to the magma ocean hypothesis for initial terrestrial planetary differentiation [Wieczoreket al., 2006]. While the general model is widely accepted, details such as mantle composition, stratification and possible overturn, lateral structure, and thermal inhomogeneities remain unresolved. The Moon experiences moonquakes at varying depths [Nakamura, 1983]. Shallow quakes are relatively large but rare, similar to terrestrial intra-plate earthquakes. Deeper quakes are comparatively smaller but more frequent, occurring periodically according to the tidal cycle. On the Moon, the lack of an atmosphere enables seismic experiments to potentially constrain meteorite impact flux, which informs cratering rates assumed throughout the solar system. The large diurnal temperature variation between day and night also induces thermal moonquakes, which may contribute to regolith production [Duennebier& Sutton, 1974; Weber et al., 2017]. Still, many questions remain regarding the frequency and distribution of natural moonquakes. This translates into an incomplete understanding of the Moons hemispherical dichotomies in crustal thickness, mare volcanism, seismicity, and the distribution of heat-producing elements. The Planetary Decadal Survey (National Research Council, 2013) identifies a New Frontiers Lunar Geophysical Network (LGN) mission to answer such questions

Upper- and mid-mantle interaction between the Samoan plume and the Tonga-Kermadec slabs

Mantle plumes are thought to play a key role in transferring heat from the core\u2013mantle boundary to the lithosphere, where it can significantly influence plate tectonics. On impinging on the lithosphere at spreading ridges or in intra-plate settings, mantle plumes may generate hotspots, large igneous provinces and hence considerable dynamic topography. However, the active role of mantle plumes on subducting slabs remains poorly understood. Here we show that the stagnation at 660 km and fastest trench retreat of the Tonga slab in Southwestern Pacific are consistent with an interaction with the Samoan plume and the Hikurangi plateau. Our findings are based on comparisons between 3D anisotropic tomography images and 3D petrological-thermo-mechanical models, which self-consistently explain several unique features of the Fiji\u2013Tonga region. We identify four possible slip systems of bridgmanite in the lower mantle that reconcile the observed seismic anisotropy beneath the Tonga slab (VSH4VSV) with thermo-mechanical calculations

Lunar Seismology Enabled by a Lunar Orbital Platform-Gateway

No abstract availabl

Geophysical Investigation of the Moon

No abstract availabl

2008 ultrasonic benchmark studies of interface curvature—a summary

In the 2008 QNDE ultrasonic benchmark session researchers from five different institutions around the world examined the influence that the curvature of a cylindrical fluid‐solid interface has on the measured NDE immersion pulse‐echo response of a flat‐bottom hole (FBH) reflector. This was a repeat of a study conducted in the 2007 benchmark to try to determine the sources of differences seen in 2007 between model‐based predictions and experiments. Here, we will summarize the results obtained in 2008 and analyze the model‐based results and the experiments