1,302 research outputs found

    Design during COVID-19: Agents and allies in the role of designer, digital fabrication and distributed production

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    During COVID-19 global emergency, designers proposed solutions at different scales, as quick responses to demands from different agents. In the same way, we critically analyzed the emergence of allies, protocols and tools, which allowed the optimization of fabrication, from traditional manufacturing into distributed co-production. The analyzed local networks produced global co-design experiences, with involvement of FabLabs and users from different disciplines. Through case studies and the evaluation of surveys and testimonials from users and makers, we analyze the global panorama, to finally explore the specific situation in Latin America. This establishes a relationship between medical demand and digital fabrication, which allows evidence of positive and negative situations to be consider as new, significant aspects for the design in the future. The leading role acquired by the ecosystem surrounding digital fabrication during the pandemic, could enhance its processes in the search for greater positioning, changing society from within the different communities

    Remote Strain Sensing of CFRP Using Microwave Frequency Domain Reflectometry

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    NASA's Advanced Composites Project is investigating technologies that increase automated remote inspection of aircraft composite structures. Therefore, microwave Frequency Domain Reflectometry (FDR) is being investigated as a method of enabling rapid remote measurement of strain occurring at the first ply of a composite fiber reinforced polymer (CFRP) structure using Radio Frequency (RF) Electro-Magnetic (EM) radiation. While microwave reflectometry has been used to detect disbonds in CFRP structures, its use in detecting strain has been limited. This work will present data demonstrating the measurement of the reactance changes due to loading conditions that are indicative of strain in a CFRP structure. In addition, the basic EM signature will be presented along with an analysis of temperature and humidity effects

    Fiber Optic Rosette Strain Gauge Development and Application on a Large-Scale Composite Structure

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    A detailed description of the construction, application, and measurement of 196 FO rosette strain gauges that measured multi-axis strain across the outside upper surface of the forward bulkhead component of a multibay composite fuselage test article is presented. A background of the FO strain gauge and the FO measurement system as utilized in this application is given and results for the higher load cases of the testing sequence are shown

    Multi-component Transparent Conducting Oxides: Progress in Materials Modelling

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    Transparent conducting oxides (TCOs) play an essential role in modern optoelectronic devices through their combination of electrical conductivity and optical transparency. We review recent progress in our understanding of multi-component TCOs formed from solid-solutions of ZnO, In2O3, Ga2O3 and Al2O3, with a particular emphasis on the contributions of materials modelling, primarily based on Density Functional Theory. In particular, we highlight three major results from our work: (i) the fundamental principles governing the crystal structures of multi-component oxide structures including (In2O3)(ZnO)n, named IZO, and (In2O3)m(Ga2O3)l(ZnO)n, named IGZO; (ii) the relationship between elemental composition and optical and electrical behaviour, including valence band alignments; (iii) the high-performance of amorphous oxide semiconductors. From these advances, the challenge of the rational design of novel electroceramic materials is discussed.Comment: Part of a themed issue of Journal of Physics: Condensed Matter on "Semiconducting Oxides". In Press (2011

    Photo-detection using Bose-condensed atoms in a micro trap

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    A model of photo-detection using a Bose--Einstein condensate in an atom-chip based micro trap is analyzed. Atoms absorb photons from the incident light field, receive part of the photon momentum and leave the trap potential. Upon counting of escaped atoms within predetermined time intervals, the photon statistics of the incident light is mapped onto the atom-count statistics. Whereas traditional photo-detection theory treats the emission centers of photo electrons as distinguishable, here the centers of escaping atoms are condensed and thus indistinguishable atoms. From this an enhancement of the photon-number resolution as compared to the commonly known counting formula is derived.Comment: 11 pages, 5 figures; revised versio

    Bribeproof mechanisms for two-values domains

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    Schummer (Journal of Economic Theory 2000) introduced the concept of bribeproof mechanism which, in a context where monetary transfer between agents is possible, requires that manipulations through bribes are ruled out. Unfortunately, in many domains, the only bribeproof mechanisms are the trivial ones which return a fixed outcome. This work presents one of the few constructions of non-trivial bribeproof mechanisms for these quasi-linear environments. Though the suggested construction applies to rather restricted domains, the results obtained are tight: For several natural problems, the method yields the only possible bribeproof mechanism and no such mechanism is possible on more general domains.Comment: Extended abstract accepted to SAGT 2016. This ArXiv version corrects typos in the proofs of Theorem 7 and Claims 28-29 of prior ArXiv versio
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