2,309 research outputs found

    Beam scanning by liquid-crystal biasing in a modified SIW structure

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    A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

    Making Connections: A Handbook for Effective Formal Mentoring Programs in Academia

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    This book, Making Connections: A Handbook for Effective Formal Mentoring Programs in Academia, makes a unique and needed contribution to the mentoring field as it focuses solely on mentoring in academia. This handbook is a collaborative institutional effort between Utah State University’s (USU) Empowering Teaching Open Access Book Series and the Mentoring Institute at the University of New Mexico (UNM). This book is available through (a) an e-book through Pressbooks, (b) a downloadable PDF version on USU’s Open Access Book Series website), and (c) a print version available for purchase on the USU Empower Teaching Open Access page, and on Amazon

    Modern meat: the next generation of meat from cells

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    Modern Meat is the first textbook on cultivated meat, with contributions from over 100 experts within the cultivated meat community. The Sections of Modern Meat comprise 5 broad categories of cultivated meat: Context, Impact, Science, Society, and World. The 19 chapters of Modern Meat, spread across these 5 sections, provide detailed entries on cultivated meat. They extensively tour a range of topics including the impact of cultivated meat on humans and animals, the bioprocess of cultivated meat production, how cultivated meat may become a food option in Space and on Mars, and how cultivated meat may impact the economy, culture, and tradition of Asia

    Modeling 4.0: Conceptual Modeling in a Digital Era

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    Digitization provides entirely new affordances for our economies and societies. This leads to previously unseen design opportunities and complexities as systems and their boundaries are re-defined, creating a demand for appropriate methods to support design that caters to these new demands. Conceptual modeling is an established means for this, but it needs to be advanced to adequately depict the requirements of digitization. However, unlike the actual deployment of digital technologies in various industries, the domain of conceptual modeling itself has not yet undergone a comprehensive renewal in light of digitization. Therefore, inspired by the notion of Industry 4.0, an overarching concept for digital manufacturing, in this commentary paper, we propose Modeling 4.0 as the notion for conceptual modeling mechanisms in a digital environment. In total, 12 mechanisms of conceptual modeling are distinguished, providing ample guidance for academics and professionals interested in ensuring that modeling techniques and methods continue to fit contemporary and emerging requirements

    Northeastern Illinois University, Academic Catalog 2023-2024

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    https://neiudc.neiu.edu/catalogs/1064/thumbnail.jp

    Advanced Manufacturing of Multilayer Ceramic Composites for Application in Solid Oxide Fuel Cells

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    This thesis investigates advanced techniques to control multilayer ceramic composite (MCC) 3D geometry and layer architecture. MCCs have tremendous potential to significantly change a variety of fields due to their ability to withstand extreme environments. However, our limited ability to shape them into complex objects impedes these efforts. To address this issue, two techniques have been introduced: fill coating and bilayer shrinkage driven self-shaping. Central to both techniques is the control of residual stresses experienced by MCCs during sintering. In the case of fill coating and the control of layer architecture, these residual stresses needed to be reduced to prevent the fracture of the novel internal cathode tubular solid oxide fuel cell (IC-tSOFC). This was achieved with the adoption of extended sintering procedures which promoted plastic deformation processes like creep stress relaxation. The novel fill coating technique used to produce IC-tSOFCs was then investigated using scanning electron microscopy (SEM) to ensure that the deposited films were highly uniform and comparable to films deposited using the more mature dip coating technique. The electrochemical performance of the IC-tSOFC was then thoroughly evaluated on a variety of fuel streams including pure hydrogen, dilute hydrogen, simulated exhaust from a boiler, and simulated exhaust from a two-stroke internal combustion engine. The second focus of this thesis takes advantage of the residual stresses that complicated IC-tSOFC development rather than dissipating them. By using the mismatch in the thermal expansion coefficient between adjacent layers within planar MCCs, curvature may be introduced. Substrates were produced using tape casting and a thin film was then added to this substrate using aerosol spray deposition. By controlling the thickness of the substrate and film, as well as the 2D shape of the substrate and pattern of the applied film, the curvature and shape of the final self-formed part was controlled. Beyond demonstration of this novel manufacturing technique, investigation into curvature and shape prediction using analytical and finite element method (FEM) modeling enabled the development of a methodology to design parts using self-shaping. Initial investigations focused on predicting curvature. Though a disagreement between modeling and experiment was observed, an experimental TEC was introduced to replicate experimental results in FEM modeling. This understanding of the 2D curvature was then extended to three dimensions to analyze shape. Predictions regarding bifurcation between cap-like and tube-like deformation modes was applied to the ceramic system using FEM modeling and experiment. These predictions were shown to be consistent with theoretical understanding. Similarly, bending direction for tube-like deformation was shown to be generally consistent with theoretical understanding, but here FEM modeling struggled to reliably predict the final 3D geometry of shapes with high degrees of symmetry, and experimental samples experienced misorientation of bending, indicating that models may need to be expanded to include a greater variety of forces controlling deformation. Overall, this thesis shows successful development of novel manufacturing techniques to enable wider application of ceramic materials. While the IC-tSOFC introduces new combined heat and power-SOFC systems to be explored, self-shaping ceramics introduces a variety of fundamental questions regarding the underlying mechanism driving bilayer shrinkage within MCCs as well as full understanding of the interaction between 2D substrate shape and film pattern at any scale
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