Engineering topics
Smith, Mark F.
Publications and source records attributed to Smith, Mark F..
Advanced manufacturing—A transformative enabling capability for fusion
Additive Manufacturing (AM) can create novel and complex engineered material structures. Features such as controlled porosity, micro-fibers and/or nano-particles, transitions in materials and integral robust coatings can be important in developing solutions for fusion subcomponents. A realistic understanding of this capability would be particularly valuable in identifying development paths. Major concerns for using AM processes with lasers or electron beams that melt powder to make refractory parts are the power required and residual stresses arising in fabrication. A related issue is the required combination of lasers or e-beams to continue heating of deposited material (to reduce stresses) and to deposit new material at a reasonable built rate while providing adequate surface finish and resolution for meso-scale features. Some Direct Write processes that can make suitable preforms and be cured to an acceptable density may offer another approach for PFCs.
Adaptive Detector Positioning for a Room PET System
Investigating human brain function in response to environmental stimuli requires freely moving humans without attached instrumentation. The RoomPET concept provides a feasible solution for human brain imaging. A RoomPET system is a room that contains an optical head tracking system and PET detectors that move to keep the head in the PET detector field-of-view. As a proof of principle, a small box-size prototype was built to demonstrate feasibility of RoomPET with gantry mechanics, tracking capabilities, and control systems.
A Room PET Scanner for Natural Environment Neuroscience Research
A room size PET scanner for neuroscience research is proposed in which subjects can move about freely in a natural environment. This scanner, termed RoomPET, would open new frontiers in the study of dynamic brain function. The key to a feasible system is PET detectors with a limited vertical dimension that may translate up and down to keep the brain in the field of view. Head position can be tracked by an array of video cameras, providing real-time data to guide detector motion and for motion-corrected image reconstruction. For a point in the center of the room and centered within the vertical field of view of the detectors, geometric sensitivity ranges between 4 and 18% for room widths of 2 to 3 m and detectors with vertical dimensions of 15 to 40 cm. Spatial resolution is dominated by annihilation photon non-colinearity due to the large detector separation. This non-colinearity contribution for F-18 is 4.4 and 6.6 mm full width at half maximum (FWHM) at the center of 2 ×2 and 3×3m 2 rooms, respectively, for a line of response orthogonal to the opposite walls. With pixelated scintillation crystal elements 2 mm on a side the system resolution for F-18 radiotracers is estimated at 4.5 and 6.7 mm FWHM for room widths of 2 and 3 m, respectively. A RoomPET system would advance the understanding of brain function in healthy humans and in those with neurological diseases, disorders and brain injury.
Additive Manufacturing at Sandia -- New Opportunties and Technical Challenges.
Abstract not provided.
Multi-layer Metallization of Polymer Materials via Thermal Spray.
Abstract not provided.
Additive Manufacturing at Sandia -- New Opportunities & Technical Challenges.
Abstract not provided.
Additive Manufacturing at Sandia -- New Opportunities & Technical Challenges.
Abstract not provided.
Advanced Manufacturing ? A Transformative Enabling Capability for Advancing Fusion.
Abstract not provided.
Status of cardiovascular PET radiation exposure and strategies for reduction: An Information Statement from the Cardiovascular PET Task Force
Cardiovascular positron emission tomography (PET) imaging provides high-quality visual and quantitative myocardial perfusion and function images. In addition, cardiovascular PET can assess myocardial viability, myocardial inflammatory disorders such as cardiac sarcoid, and infections of implanted devices including pacemakers, ventricular assist devices, and prosthetic heart valves. As with all nuclear cardiology procedures, the benefits need to be considered in relation to the risks of exposure to radiation. When performed properly, these assessments can be obtained while simultaneously minimizing radiation exposure. The purpose of this information statement is to present current concepts to minimize patient and staff radiation exposure while ensuring high image quality.
Additive Manufacturing -- A New World of Opportunities and Challenges.
Abstract not provided.
Additive Manufacturing ? A New World of Opportunities and Challenges.
Abstract not provided.
Additive Manufacturing -- A New World of Opportunities and Challenges.
Abstract not provided.
Additive Manufacturing --A New World of Opportunities and Challenges.
Abstract not provided.