4,549 research outputs found

    Leonardo da Vinci's Contributions from a Design Perspective

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    [EN] The figure of Leonardo da Vinci has been extensively studied. In fact, the Leonardiana Library brings together tens of thousands of titles on Leonardo and his work. During the second half of the 20th century, various treaties were published focusing on Leonardo¿s activity as an engineer, and more recently, an increasing number of scientific articles that focus on certain aspects of the prolific work of the genius such as construction, mechanics, strength of materials, etc. have been published. This article analyses the main contributions of the Tuscan genius in the field of design focusing on his processes for generating new solutions, his developments regarding graphic representation techniques, his improvements in plotting and measuring instruments, and how some of his devices were implemented and continue to maintain their usefulness.Cerveró-Meliá, E.; Capuz-Rizo, SF.; Ferrer-Gisbert, P. (2020). Leonardo da Vinci's Contributions from a Design Perspective. Designs. 4(3):1-20. https://doi.org/10.3390/designs4030038S12043Braha, D., & Maimon, O. (1997). The design process: properties, paradigms, and structure. IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Humans, 27(2), 146-166. doi:10.1109/3468.554679Criteria for Accrediting Engineering Programs, 2019–2020 https://www.abet.org/accreditation/accreditation-criteria/criteria-for-accrediting-engineering-programs-2019-2020/#definitionsVeltman, K. H. (2008). Leonardo da Vinci: A Review. Leonardo, 41(4), 381-388. doi:10.1162/leon.2008.41.4.381Innocenzi, P. (2020). Leonardo and the Design of Machines. Advances in Intelligent Systems and Computing, 36-46. doi:10.1007/978-3-030-41018-6_5Oliveira, A. R. E. (2019). The Mechanical Sciences in Leonardo da Vinci’s Work. Advances in Historical Studies, 08(05), 215-238. doi:10.4236/ahs.2019.85016Jaramillo, H. E. (2011). Un Análisis de la Resistencia de Materiales a partir de los Postulados de «Consideraciones y Demostraciones Matemáticas sobre dos Nuevas Ciencias» de Galileo Galilei. Lámpsakos, (5), 53. doi:10.21501/21454086.819Reciprocating machine for weight lifting (Argano), Codex Atlanticus f. 30 v, (1478–1480) https://commons.wikimedia.org/wiki/File:Reproduction_of_page_from_notebook_of_Leonardo_da_Vinci_showing_a_geared_device_assembled_and_disassembled_LCCN2006681098.jpgModel at the Museum of Science and Technology of Milan https://commons.wikimedia.org/wiki/File:Argano_sollevatore_pesi_Leonardo_Museo_scienza_e_tecnologia_Milano.jpgMap of the Val di Chiana, Royal Collection, RLW 12278, (1502–1504) https://commons.wikimedia.org/wiki/File:Val_di_Chiana.jpgReproduction of a compass designed by Leonardo https://commons.wikimedia.org/wiki/File:Compas_Léonard_de_Vinci.JPGProportional or reduction compass. Forster Codex I f. 45 (1485) https://commons.wikimedia.org/wiki/File:Reduction_Compass_Leonardo.jpgParabolic Compass. Codex Atlanticus f. 1093 r https://upload.wikimedia.org/wikipedia/commons/archive/0/03/20171027130237%21Leonardo_parabolic_compass.JPG.Detail of the Codex Atlanticus f. 5 r. Enlarged detail of the prospectograph being used by Leonardo https://commons.wikimedia.org/wiki/File:Codice_Atlantico_-_Perspectograph.jpgStudy ot two odometers. Codex Atlanticus, f. 1b r https://commons.wikimedia.org/wiki/File:Odomètre-Léonard.jpgOdometer model. Museo Nazionale della Scienza e della Tecnologia Leonardo da Vinci. (National Museum of Science and Technology of Milan) https://commons.wikimedia.org/wiki/File:Odometro_a_carriola_-_Museo_scienza_tecnologia_Milano_09908_01.jpgPugno, N. M. (2019). The commemoration of Leonardo da Vinci. Meccanica, 54(15), 2317-2324. doi:10.1007/s11012-019-01099-9Study for the mechanism of a manual lift (1495–1497), Madrid Codex I, f. 9 r https://commons.wikimedia.org/wiki/File:Ascenceur_à_manivelle-Léonard.jpgStudy of a piling machine. Codex Atlanticus, f 785, Ambrosian Library of Milan https://commons.wikimedia.org/wiki/File:Sonnette-Léonard.jpgModel of Leonardo’s pile machine, at the National Museum of Science and Technology of Milan https://commons.wikimedia.org/wiki/File:Battipalo_-_Museo_scienza_tecnologia_Milano_00040_01.jpgDetail of a mechanical jack, Codex Atlanticus, f. 0998 r, Ambrosian Library of Milan https://commons.wikimedia.org/wiki/File:Cric-Léonard.jpgManuscript of the self-propelled vehicle, Codex Atlanticus, f. 812 r (1478-1480), Ambrosiana Library of Milan https://commons.wikimedia.org/wiki/File:Leonardo_da_vinci,_Automobile.jpgModel of the self-propelled vehicle, at the National Museum of Science and Technology of Milan https://commons.wikimedia.org/wiki/File:Carro_semovente_-_Museo_scienza_tecnologia_Milano_09082_02.jp

    Integer Programming Formulations for Approximate Packing Circles in a Rectangular Container

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    A problem of packing a limited number of unequal circles in a fixed size rectangular container is considered. The aim is to maximize the (weighted) number of circles placed into the container or minimize the waste. This problem has numerous applications in logistics, including production and packing for the textile, apparel, naval, automobile, aerospace, and food industries. Frequently the problem is formulated as a nonconvex continuous optimization problem which is solved by heuristic techniques combined with local search procedures. New formulations are proposed for approximate solution of packing problem. The container is approximated by a regular grid and the nodes of the grid are considered as potential positions for assigning centers of the circles. The packing problem is then stated as a large scale linear 0-1 optimization problem. The binary variables represent the assignment of centers to the nodes of the grid. Nesting circles inside one another is also considered. The resulting binary problem is then solved by commercial software. Numerical results are presented to demonstrate the efficiency of the proposed approach and compared with known results

    Realizing the physics of motile cilia synchronization with driven colloids

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    Cilia and flagella in biological systems often show large scale cooperative behaviors such as the synchronization of their beats in "metachronal waves". These are beautiful examples of emergent dynamics in biology, and are essential for life, allowing diverse processes from the motility of eukaryotic microorganisms, to nutrient transport and clearance of pathogens from mammalian airways. How these collective states arise is not fully understood, but it is clear that individual cilia interact mechanically,and that a strong and long ranged component of the coupling is mediated by the viscous fluid. We review here the work by ourselves and others aimed at understanding the behavior of hydrodynamically coupled systems, and particularly a set of results that have been obtained both experimentally and theoretically by studying actively driven colloidal systems. In these controlled scenarios, it is possible to selectively test aspects of the living motile cilia, such as the geometrical arrangement, the effects of the driving profile and the distance to no-slip boundaries. We outline and give examples of how it is possible to link model systems to observations on living systems, which can be made on microorganisms, on cell cultures or on tissue sections. This area of research has clear clinical application in the long term, as severe pathologies are associated with compromised cilia function in humans.Comment: 31 pages, to appear in Annual Review of Condensed Matter Physic

    Cultural Dimension Interests, the Dance of Negotiation, and Weather Forecasting: A Perspective on Cross-Cultural Negotiation and Dispute Resolution

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    This article will argue that effective cross-cultural negotiations and dispute resolution requires an understanding of Cultural Dimension Interests (CDI). The article will review many of the cultural interests that impact negotiation and dispute resolution by: 1) specifically reviewing the cultural theories of Edward T. Hall, Geert Hofstede, Fons Trompenaars and Charles M. Hampden-Turner, and Richard D. Lewis, 2) considering country specific anecdotal accounts of national negotiating behaviors, and 3) reviewing some specific beliefs, behaviors, and practices that impact national negotiation styles and approaches. This article will focus mainly on cross-cultural differences between American and Asian negotiation styles and behaviors

    Information-Theoretic Active Perception for Multi-Robot Teams

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    Multi-robot teams that intelligently gather information have the potential to transform industries as diverse as agriculture, space exploration, mining, environmental monitoring, search and rescue, and construction. Despite large amounts of research effort on active perception problems, there still remain significant challenges. In this thesis, we present a variety of information-theoretic control policies that enable teams of robots to efficiently estimate different quantities of interest. Although these policies are intractable in general, we develop a series of approximations that make them suitable for real time use. We begin by presenting a unified estimation and control scheme based on Shannon\u27s mutual information that lets small teams of robots equipped with range-only sensors track a single static target. By creating approximate representations, we substantially reduce the complexity of this approach, letting the team track a mobile target. We then scale this approach to larger teams that need to localize a large and unknown number of targets. We also examine information-theoretic control policies to autonomously construct 3D maps with ground and aerial robots. By using Cauchy-Schwarz quadratic mutual information, we show substantial computational improvements over similar information-theoretic measures. To map environments faster, we adopt a hierarchical planning approach which incorporates trajectory optimization so that robots can quickly determine feasible and locally optimal trajectories. Finally, we present a high-level planning algorithm that enables heterogeneous robots to cooperatively construct maps

    3D printed concrete bridges : Opportunities, Challenges, and Conditions

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    Master's thesis in Civil and structural engineering (BYG508

    The physics of streamer discharge phenomena

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    In this review we describe a transient type of gas discharge which is commonly called a streamer discharge, as well as a few related phenomena in pulsed discharges. Streamers are propagating ionization fronts with self-organized field enhancement at their tips that can appear in gases at (or close to) atmospheric pressure. They are the precursors of other discharges like sparks and lightning, but they also occur in for example corona reactors or plasma jets which are used for a variety of plasma chemical purposes. When enough space is available, streamers can also form at much lower pressures, like in the case of sprite discharges high up in the atmosphere. We explain the structure and basic underlying physics of streamer discharges, and how they scale with gas density. We discuss the chemistry and applications of streamers, and describe their two main stages in detail: inception and propagation. We also look at some other topics, like interaction with flow and heat, related pulsed discharges, and electron runaway and high energy radiation. Finally, we discuss streamer simulations and diagnostics in quite some detail. This review is written with two purposes in mind: First, we describe recent results on the physics of streamer discharges, with a focus on the work performed in our groups. We also describe recent developments in diagnostics and simulations of streamers. Second, we provide background information on the above-mentioned aspects of streamers. This review can therefore be used as a tutorial by researchers starting to work in the field of streamer physics.Comment: 89 pages, 29 figure

    Laser Ranging Interferometry for Future Gravity Missions : Instrument Design, Link Acquisition and Data Calibration

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    The presented study aims to improve the design solution adopted for the Laser Ranging Instrument of the GRACE Follow-On mission in terms of instrument layout, algorithms for the laser link acquisition and techniques for mitigating the range measurement noise. The first part of this work describes viable layout solutions of a heterodyne interferometer employed for intra-satellite range metrology and the major noise contributions which degrade the overall accuracy of the instrument. Together with the optical layout of the instrument, novel design concepts of the instrumenta s subsystems are also analyzed and tested. Precisely, a phasemeter designed to autonomously acquire and track a heterodyne signal with low signal-to-noise ratio in a frequency band that spans from 1MHz to 25MHz is presented. Particular attention is also dedicated to the mathematical modeling of the steering mirror dynamics and to the enhancement of its pointing performance by means of feedforward control. In the second part of this work, solutions for autonomously acquiring a laser signal buried in noise are analyzed and put in relation with the boundary constraints of the acquisition problem. The acquisition algorithms presented and the robustness of their design is verified mainly using numerical simulations. Experimental tests have also been performed for validating the simulation hypothesis and verifying their compliancy to a realistic mission scenario. The last part of this work describes a calibration algorithm which has been developed for minimizing, during data post-processing, the noise due to the tilt-to-piston coupling which represents one of the highest contributors to the overall measurement noise

    National Educators' Workshop: Update 1991. Standard Experiments in Engineering Materials Science and Technology

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    Given here is a collection of experiments presented and demonstrated at the National Educators' Workshop: Update 91, held at the Oak Ridge National Laboratory on November 12-14, 1991. The experiments related to the nature and properties of engineering materials and provided information to assist in teaching about materials in the education community
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