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Processing Of Alnico Magnets By Additive Manufacturing, Emma White, Emily Rinko, Timothy Prost, Timothy Horn, Christopher Ledford, Christopher Rock, Iver E. Anderson Nov 2019

Processing Of Alnico Magnets By Additive Manufacturing, Emma White, Emily Rinko, Timothy Prost, Timothy Horn, Christopher Ledford, Christopher Rock, Iver E. Anderson

Ames Laboratory Accepted Manuscripts

Permanent magnets without rare earth (RE) elements, such as alnico, will improve supply stability and potentially decrease permanent magnet cost, especially for traction drive motors and other increased temperature applications. Commercial alnico magnets with the highest energy product are produced by directional solidification (DS) to achieve a <001> columnar grain orientation followed by significant final machining, adding to the high cost. Additive manufacturing (AM) is an effective method to process near net-shape parts with minimal final machining of complex geometries. AM also, has potential for texture/grain orientation control and compositionally graded structures. This report describes fabrication of alnico magnets by ...


Multiple-Model Adaptive Control Of A Hybrid Solid Oxide Fuel Cell Gas Turbine Power Plant Simulator, Alex Tsai, Paolo Pezzini, David Tucker, Kenneth M. Bryden Aug 2019

Multiple-Model Adaptive Control Of A Hybrid Solid Oxide Fuel Cell Gas Turbine Power Plant Simulator, Alex Tsai, Paolo Pezzini, David Tucker, Kenneth M. Bryden

Ames Laboratory Accepted Manuscripts

A multiple model adaptive control (MMAC) methodology is used to control the critical parameters of a solid oxide fuel cell gas turbine (SOFC-GT) cyberphysical simulator, capable of characterizing 300 kW hybrid plants. The SOFC system is composed of a hardware balance of plant (BoP) component, and a high fidelity FC model implemented in software. This study utilizes empirically derived transfer functions (TFs) of the BoP facility to derive the MMAC gains for the BoP system, based on an estimation algorithm which identifies current operating points. The MMAC technique is useful for systems having a wide operating envelope with nonlinear dynamics ...


Direct Observation Of Early Stages Of Growth Of Multilayered Dna-Templated Au-Pd-Au Core-Shell Nanoparticles In Liquid Phase, Nabraj Bhattarai, Tanya Prozorov Feb 2019

Direct Observation Of Early Stages Of Growth Of Multilayered Dna-Templated Au-Pd-Au Core-Shell Nanoparticles In Liquid Phase, Nabraj Bhattarai, Tanya Prozorov

Ames Laboratory Accepted Manuscripts

We report here on direct observation of early stages of formation of multilayered bimetallic Au-Pd core-shell nanocubes and Au-Pd-Au core-shell nanostars in liquid phase using low-dose in situ scanning transmission electron microscopy (S/TEM) with the continuous flow fluid cell. The reduction of Pd and formation of Au-Pd core-shell is achieved through the flow of the reducing agent. Initial rapid growth of Pd on Au along <111> direction is followed by a slower rearrangement of Pd shell. We propose the mechanism for the DNA-directed shape transformation of Au-Pd core-shell nanocubes to adopt a nanostar-like morphology in the presence of T30 DNA ...