1,720,956 research outputs found
3B baskili beton: çok ölçekli mekanik karakterizasyon ve hesaplamali modelleme
No full textThis thesis presents a comprehensive exploration of the physical, mechanical, and thermal properties of 3D Printed Concrete (3DPC) structures across micro, meso, and macrostructural scales. The central focus is the analysis of full-scale walls under rigorous mechanical tests, revealing a notable and novel discovery: the mechanical properties —compressive strength, elastic modulus, and tensile strength— of the lower part of the 3DPC walls enhanced by up to 108%, 53%, and 100%, respectively, compared to the upper parts. This novel and dominant elevation effect on mechanical properties surpasses the previously known anisotropic behavior in 3DPC.
The investigation extends to material modeling, introducing the Continuum Damage Plasticity Model (CDPM) for cyclic loading of concrete. The numerical implementation using the Backward-Euler method is meticulously examined. Micro and meso scales are scrutinized using computed tomograms (CT), shedding light on anisotropic behavior due to porosity and interlayer effects through finite element methods by using CDPM and traction-separation laws.
The macrostructural assessment involves subjecting 3DPC walls to lateral loads up to failure for earthquake performance. Digital image correlation method is used to evaluate displacement counters and fracture behavior of these walls. The contributions of individual components, including truss and web elements, are thoroughly examined using finite element simulations.
This thesis not only expands the understanding of the anisotropic behavior of 3DPC but reveals a novel and more dominant elevation effect on mechanical properties. These findings contribute significantly to existing knowledge and bear important implications for future research and practical applications in the realm of 3DPC.Bu yüksek lisans tezi, mikro, mezo ve makro yapısal ölçeklerde 3B Baskılı Beton (3BBB) yapıların fiziksel, mekanik ve termal özelliklerinin kapsamlı bir araştırmasını sunmaktadır. Tezin ana odağı, özenli mekanik testler altında tam ölçekli duvarların analizleri olup dikkate değer ve yeni bir keşfi ortaya çıkarmaktadır: 3BBB duvarlarının alt kısmının mekanik özellikleri (basınç dayanımı, elastik modül ve çekme dayanımı) üst kısımlara kıyasla sırasıyla %108, %53 ve %100'e kadar artmıştır. Bu yeni ve baskın yükseklik etkisinin mekanik özellikler üzerindeki etkisi, 3BBB malzemesinde daha önce bilinen anizotropik davranışı domine etmektedir.
Araştırma, çevrimsel beton yüklemesi için Sürekli Hasar Plastiklik Modelini (CDPM) sunarak malzeme modellemeye de uzanmaktadır. Geriye doğru Euler yöntemi kullanılarak yapılan sayısal uygulama titizlikle incelenmiştir. Mikro ve mezo ölçekler, bilgisayarlı tomografiler (BT) kullanılarak incelenmekte, CDPM ve çekme-ayırma yasaları kullanılarak sonlu eleman yöntemleri aracılığıyla gözeneklilik ve ara katman etkilerinden kaynaklanan anizotropik davranışa ışık tutulmaktadır.
Makro yapısal değerlendirme, 3BBB duvarların deprem performansı için kırılmaya kadar yanal yüklere maruz bırakılmasını içerir. Bu duvarların yer değiştirme ölçümlerini ve kırılma davranışını değerlendirmek için dijital görüntü korelasyonu yöntemi kullanılmaktadır. Kafes ve gövde elemanları dahil olmak üzere münferit bileşenlerin katkıları, sonlu eleman simülasyonları kullanılarak kapsamlı bir şekilde incelenmiştir.
Bu tez, sadece 3BBB malzemesinin anizotropik davranışı hakkındaki anlayışı genişletmekle kalmaz, daha da önemlisi mekanik özellikler üzerinde yeni ve daha baskın bir yükseklik etkisini ortaya çıkarır. Bulgular, mevcut bilgiye önemli ölçüde katkıda bulunmakta olup, 3BBB alanında gelecekteki araştırmalar ve pratik uygulamalar için sonuçlar doğurmaktadır.M.S. - Master of Scienc
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
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
Dataset for Modeling Anisotropy in 3D Printed Concrete
Get PDFThis dataset supports the study titled “A Semi-Empirical Framework for Modeling Anisotropy, Spatial Variation and Failure Mechanisms in 3D Printed Concrete”. It includes high-resolution computed tomography (CT) images, validated Abaqus input files for simulating cylindrical 3D-printed concrete (3DPC) cores, and a MATLAB-based CDP parameter generator for automated material calibration. The dataset enables reproducible finite element simulations that capture direction-dependent mechanical behavior and failure modes in 3DPC using a hybrid modeling approach. All resources have been structured to facilitate ease of use, promote transparency, and support further research on the mechanical modeling of additive manufacturing-based cementitious materials.TUBİTAK under grant agreement 120N990Research Universities Support Fund (ADEP-303-2022-11174
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
A semi-empirical framework for modeling anisotropy, spatial variation and failure mechanisms in 3D printed concrete
No full textThis study introduces a modeling approach to simulate the anisotropic mechanical behavior of 3D-printed concrete (3DPC), considering the influence of porosity inherent to the printing process. Computed tomography (CT) scans of cylindrical cores extracted from a 2.35 m 3DPC wall revealed two key porosity types: large and elongated voids at interlayer-interstrip intersections and finer pores within and between layers. Building on these observations, a novel Equivalent Porosity Geometry (EPG) representation was developed to idealize interface porosity through mechanically representative shapes, while the porosity effects in the intralayer matrix was incorporated using spatially calibrated parameters within an isotropic Concrete Damage Plasticity (CDP) framework. The proposed approach predicted anisotropic mechanical properties (compressive strength, elastic modulus, and Poisson's ratio) with strong agreement to experimental data, capturing spatial property variations along the wall height and reliably reproduced the direction-dependent ascending portion of the compressive stress–strain response. Furthermore, the numerically observed fracture patterns aligned with experimental results, capturing fracture initiation at the tips of interfacial voids and revealing the progressive failure mechanisms responsible for anisotropic behavior in 3DPC. A comparative analysis with existing models highlights the superior predictive performance and practical scalability of the semi-empirical framework. Drawing from both continuum and interface-based modeling strategies, proposed hybrid modeling strategy offers a physically grounded and computationally efficient tool for linking CT-derived porosity to anisotropic mechanical behavior, supporting future optimization of printing parameters and structural design in 3DPC
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