125,174 research outputs found
Thermodynamically consistent multiscale formulation of a thermo-mechanical problem with phase transformations
No full textA multiscale framework for thermo-mechanical analysis with phase transformations is proposed in this work. The formulation covers those cases including coupled constitutive equations for simulating thermo-mechanical processes considering phase transformation phenomena. The general case of temperature- and phase-dependent procedures, involving nonlinear plasticity concepts, is considered as main framework in order to formulate the material dissipation at both micro- and macroscopic level of observation. Thermodynamic consistency conditions for computational up/downscaling between micro- and macroscales are presented, with special focus on phase transformation phenomena, for both the mechanical and thermal homogenization. Classical Coleman–Gurtin thermodynamics is employed at the microscale, whereas an extended framework is considered at the macroscale due to the temperature gradient dependency of the macro stress. The multiscale procedure is based on a variational approach largely discussed in the literature. The overall coupled process at both micro- and macroscopic scales, averaging criteria, thermal, mechanical and phase change constitutive expressions, as well as the corresponding homogenization rules, are discussed and derived in detail.Fil: Said Schicchi, Diego. Leibniz Institut für Werkstofforientierte Technologien ; AlemaniaFil: Caggiano, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Universitat Technische Darmstadt; AlemaniaFil: Hunkel, Martin. Leibniz Institut für Werkstofforientierte Technologien ; AlemaniaFil: Koenders, Eduardus A. B.. Universitat Technische Darmstadt; Alemani
Correction: Automatic generation of high-fidelity representative volume elements and computational homogenization for the determination of thermal conductivity in foamed concretes (Materials and Structures, (2023), 56, 10, (179), 10.1617/s11527-023-02253-2)
No full textThe article 'Automatic generation of high-fidelity representative volume elements and computational homogenization for the determination of thermal conductivity in foamed concretes', written by Víctor D. Fachinotti, Ignacio Peralta, Sebastián Toro, Bruno A. Storti and Antonio Caggiano, was originally published in volume 56, issue 10, Article 179 without open access. With the society's decision to grant Open Choice the copyright of the article changed in April 2024 to © The Author(s) 2023 and the article is forthwith distributed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0. Open access funding enabled and organized by RILEM
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A mesoscale approach for modeling capillary water absorption and transport phenomena in cementitious materials
No full textThis paper proposes a mesoscale approach for simulating moisture transport by capillary action in partly-saturated porous cementitious composites. The modeling approach explicitly accounts for moisture transport through a mesostructure composed of coarse aggregates, surrounding cementitious mortar and interfaces. These latter, namely interface transition zones (ITZs), allow to describe the interaction between aggregates and mortar, and may cause an alternative path for the internal moisture movements. Basic morphology effects of the ITZs are simulated using a ribbon approach. Random spatial distribution of cement particles are stacked in the meso-geometry. Aggregate particles are introduced as randomly perturbed polygons and the moisture transport is modeled as a diffusion problem and solved by means of the finite element method. The proposed constitutive models are based on a proper description of the permeability and pore size distribution which strongly affect the local moisture content. Numerical results at both macro- and mesoscale levels demonstrate the soundness and capability of the proposed approach. The integrated modeling results actually demonstrate the potential of the mesoscale approach and shows the role of the ITZs as an internal interconnected network.Fil: Caggiano, Antonio. Universitat Technische Darmstadt; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Said Schicchi, Diego. Leibniz-Institut Für Werkstofforientierte Technologien; Alemania. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Mankel, Christoph. Universitat Technische Darmstadt; AlemaniaFil: Ukrainczyk, Neven. Universitat Technische Darmstadt; AlemaniaFil: Koenders, Eduardus A. B.. Universitat Technische Darmstadt; Alemani
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Lampedusa: una tragedia con molti interrogativi : obblighi di tutela dei diritti fondamentali e strumenti di controllo dell'immigrazione
No full textOptimization of multilayered walls for building envelopes including PCM-based composites
No full textThis work proposes a numerical procedure to simulate and optimize the thermal response of a multilayered wallboard system for building envelopes, where each layer can be possibly made of Phase Change Materials (PCM)-based composites to take advantage of their Thermal-Energy Storage (TES) capacity. The simulation step consists in solving the transient heat conduction equation across the whole wallboard using the enthalpy-based finite element method. The weather is described in detail by the Typical Meteorological Year (TMY) of the building location. Taking the TMY as well as the wall azimuth as inputs, EnergyPlusTM is used to define the convective boundary conditions at the external surface of the wall. For each layer, the material is chosen from a predefined vade mecum, including several PCM-based composites developed at the Institut für Werkstoffe im Bauwesen of TU Darmstadt together with standard insulating materials (i.e., EPS or Rockwool). Finally, the optimization step consists in using genetic algorithms to determine the stacking sequence of materials across the wallboard to minimize the undesired heat loads. The current simulation-based optimization procedure is applied to the design of envelopes for minimal undesired heat losses and gains in two locations with considerably different weather conditions, viz. Sauce Viejo in Argentina and Frankfurt in Germany. In general, for each location and all the considered orientations (north, east, south and west), optimal results consist of EPS walls containing a thin layer made of the PCM-based composite with highest TES capacity, placed near the middle of the wall and closer to the internal surface.Fil: Fachinotti, Victor Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Bre, Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Mankel, Christoph. Universitat Technische Darmstadt; AlemaniaFil: Koenders, Eduardus A. B.. Universitat Technische Darmstadt; AlemaniaFil: Caggiano, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentin
Resource efficiency enhancement in sheet metal cutting industrial networks through cloud manufacturing
No full textIn modern manufacturing industry, resource efficiency is negatively affected by the high fluctuations of demands within the global market. In this work, an intelligent cloud manufacturing platform is proposed to increase resource efficiency, productivity, and utilization rates in a smart manufacturing network by dynamically matching manufacturing services offers and requests through the broad sharing and on-demand delivery of distributed computational, software, digital, and physical manufacturing resources. The cloud platform is developed with particular reference to the sheet metal cutting sector and includes several modules. A database module is employed for users data input and storage. An intelligent assessment and optimization module performs the functional and geometrical assessments of the sheet metal cutting instances entered by customers and suppliers and makes use of a genetic algorithm to optimize the manufacturing solutions with specific attention to the surface utilization rate, as key performance index of resource efficiency. A decision-making module supports the supplier in the selection of the best production strategy and the customer in the evaluation and comparison of the best manufacturing solutions ranked according to the preferred criteria. To demonstrate the implementation of the proposed cloud manufacturing platform in a manufacturing network scenario, a case study including several customer and supplier instances is presented, showing the multiple manufacturing solutions proposed by the platform and the advantages in terms of industrial resource efficiency improvement
Globalization and labor market integration in late nineteenth and early twentieth century Asia
No full textThis chapter uses new data sets to analyze labor market integration between 1882 and 1936 in an area of Asia stretching from South India to Southeastern China and encompassing the three Southeast Asian countries of Burma, Malaya, and Thailand. We find that by the late nineteenth century, globalization, of which a principal feature was the mass migration of Indians and Chinese to Southeast Asia, gave rise to both an integrated Asian labor market and a period of real wage convergence. Integration did not, however, extend beyond Asia to include core industrial countries. Asian and core areas, in contrast to globally integrated commodity markets, showed divergent trends in unskilled real wages
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