1,721,010 research outputs found
Potentials of Steel Fibres for Mesh Mould Elements
No full textISSN:2211-0844ISSN:2211-0852ISSN:2211-085
Feasibility of Using Low CO2 Concrete Alternatives in Extrusion-Based 3D Concrete Printing
No full textIn conventional concrete, replacing high-volume (more than 45%) of ordinary Portland cement (OPC) by supplementary cementitious materials (SCMs) is not a novel CO2 reduction method, whereas rarely in 3D printable concrete. This study attempts to explore the feasibility of using SCMs in 3D printable concrete. Initially, the existing binder mixes, required fresh properties and a research method of 3D printable concrete are investigated by reviewing the relevant papers. Additionally, the constraints and opportunities of using SCMs in 3D printable concrete are illustrated and summarized. Finally, it has been found that up to 45% of cement can be replaced by a blend of fly ash and silica fume. The essential fresh properties of 3D printable concrete include extrudability, workability, open time, buildability and structural build-up, which are influenced by the binder mix, particle size distribution, water to binder ratio, binder to aggregate ratio, admixture addition, the dosage of reinforced-fibers, etc. On the other hand, there are many limitations to develop SCMs-based 3D printable concrete, such as few relevant studies, a lack of the certificated standard, massive related-parameters and the shortage of common SCMs. For the first three problems, it can be solved with the development of 3D printable concrete. For the last one, calcined clay is one potential alternative for developing sustainable 3D printable concrete in the areas where are in short supply of fly ash and silica fume.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and EnvironmentStructural Design & Mechanic
Challenges of Real-Scale Production with Smart Dynamic Casting
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Exploiting the Potential of Digital Fabrication for Sustainable and Economic Concrete Structures
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Fibers orientation and mechanical performance of HPFRC in 3D printed molds
Get PDFLAUREA MAGISTRALEGovernare la dispersione e l'orientamento delle fibre nel calcestruzzo attraverso un insieme opportunamente bilanciato di proprietà di stato fresco e una procedura di colata accuratamente progettata, è un modo fattibile ed economico per ottenere prestazioni meccaniche superiori di materiali compositi fibrorinforzati, che possono essere richiesti dall'applicazione prevista, mantenendo anche il contenuto di fibre a valori relativamente bassi. Lo scopo di questo lavoro è quello di studiare come l'orientamento delle fibre indotto attraverso la modellazione 3D della cassaforma consenta un aumento della resistenza alla flessione in calcestruzzi rinforzati con fibre ad alte prestazioni. Per ottenere ciò, sono stati scelti una serie di 16 campioni parallelepipedi a denti, divisi per categoria di altezza del dente, con un'altezza totale di 32 mm, larghezza di 116 mm e lunghezza di 360 mm. Il lavoro aveva lo scopo di verificare se i metodi di fusione e la geometria (che era stata progettata per "riprodurre" le peculiarità degli elementi stampati in 3D). In prima analisi è stata effettuata una dettagliata analisi sull’impiego di tecnologia di modellazione 3D nel campo delle costruzioni, delineando i suoi limiti e i vantaggi. Successivamente, una breve descrizione delle caratteristiche del fiber reinforced concrete e i suoi campi di applicazione precede l’esperienza vera e propria. In essa si svolge il viaggio che parte, come in tutte le ricette di un ristorante stellato Michelin, dall’elenco degli ingredienti per creare i campioni parallelepipedi dentellati in cemento fibrorinforzato e prosegue con il metodo utilizzato per ottenere i risultati richiesti, fino alla fase di assemblamento del cibo nel piatto, in cui i risultati attireranno la curiosità del lettore. Inoltre, è stato spiegato come le modalità del flusso fresco di calcestruzzo e le caratteristiche geometriche del cassero inducano un orientamento prestabilito delle fibre con il quale governarle in fase di getto. Per concludere, una relazione che lega i parametri di orientamento e la capacità resistente a flessione dei provini è stata accuratamente trovata.Governing the dispersion and the orientation of fibres in concrete through a suitably balanced set of fresh state properties and a carefully designed casting procedure, is a feasible and cost-effective way to achieve a superior mechanical performance of fibre reinforced cementitious composites, which may be required by the intended application, even keeping the fibre content at relatively low values. The purpose of this work is to investigate how the fibers orientation induced through the 3D modeling of the formwork allows an increase in flexural strength in high-performance fiber-reinforced concretes. To achieve this, a series of 16 toothed parallelepiped specimens, divided by tooth height category, with a total height of 32mm, width of 116mm and length of 360mm were casted. The work was intended to verify whether the casting methods and the geometry (which was designed to "reproduce" the peculiarities of 3D printed elements).
Initially, a detailed analysis which deals with the use of 3D modeling technology in the construction field, outlining its limits and advantages was carried out. Subsequently, a brief description of the characteristics of fiber reinforced concrete and its fields of application precedes the actual experience. In it takes place the journey that starts, as in all the recipes of a Michelin-starred restaurant, from the list of ingredients to create toothed parallelepiped samples in fiber-reinforced cement and continues with the method used to obtain the required results, up to the assembly of the food on the plate, in which the results will attract the reader's curiosity. Furthermore, it was explained how the modalities of the fresh concrete flow and the geometrical characteristics of the formwork induce a predetermined orientation of the fibers with which to govern them during the casting. To conclude, a report that bonds the orientation parameters and the bending resistant capacity of the specimens has been carefully found
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
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