1,720,968 research outputs found
3D printing of bio-based photocurable slurries prepared with waste-derived glass
No full textThis study investigates waste-derived glass materials in 3D printing slurries through vat polymerization technologies, utilizing biobased photocurable formulations derived from acrylate epoxidized soybean oil (AESO).
Waste materials, including mineral wool and glass from municipal waste incinerator bottom ash vitrification,
were milled, sieved, and characterized to ensure a particle size distribution under 50 μm. Thermal analyses were
conducted to understand the glass-based materials’ thermal behavior and the polymeric formulation’s decomposition, allowing for the optimization of thermal treatment parameters. These powders were mixed with AESO
formulations to create photocurable slurries containing up to 60 wt% ceramic loadings. Rheological and photorheological tests demonstrated satisfactory flowability (0.2–10 Pa⋅s) and high photo reactivity for 3D printing.
Subsequently, thermal treatments at 950 ◦C were applied to consolidate the printed objects, removing the resin
component and forming glass-ceramic structures. The results highlight the significant potential of this method for
producing porous glass-ceramic materials, offering promising opportunities for sustainable material reuse and
advanced manufacturing processes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
3D printed electrolyte-supported solid oxide cells based on Ytterbium-doped scandia-stabilized zirconia
Full text linkSolid oxide cells (SOC) are an efficient and cost-effective energy conversion technology able to operate reversibly in fuel cell and electrolysis mode. Electrolyte-supported SOC have been recently fabricated employing 3D printing to generate unique geometries with never-explored capabilities. However, the use of the state-of-the-art electrolyte based on yttria-stabilized zirconia limits the current performance of such printed devices due to a limited oxide-ion conductivity. In the last years, alternative electrolytes such as scandia-stabilized zirconia (ScSZ) became more popular to increase the performance of electrolyte-supported cells. In this work, stereolithography 3D printing of Ytterbium-doped ScSZ was developed to fabricate SOC with planar and corrugated architectures. Symmetrical and full cells with about 250 μm- thick electrolytes were fabricated and electrochemically characterized using impedance spectroscopy and galvanostatic studies. Maximum power density of 500 mW cm−2 in fuel cell mode and an injected current of 1 A cm−2 at 1.3 V in electrolysis mode, both measured at 900 °C, were obtained demonstrating the feasibility of 3D printing for the fabrication of high-performance electrolyte-supported SOC. This, together with excellent stability proved for more than 350 h of operation, opens a new scenario for using complex-shaped SOC in real applications
Modeling of a Single Repeating Unit for Protonic Ceramic Cell Applications
No full textProtonic Ceramic Cells (PCCs) are a promising alternative to oxygen-ion conducting solid oxide cells (SOCs), offering benefits for hydrogen separation, electrolysis and fuel cell applications. The current development stage is focusing on the scale-up of the
technology to cross the gap between single cells and stacks. The design of single repeating units (SRU) is the intermediate stage of the development. This work developed a numerical model for the 3D steady-state simulations of an SRU geometry designed for a circular, anode-supported PCC. The model has been applied to the simulation of fuel cell operation and has been calibrated using experimental data from the literature. The model is able to accurately reproduce experimental results obtained at 600 °C. The simulation platform developed can be also adapted to the simulation of electrolysis operation and can be applied to the optimization of the SRU geometry
Lombardy region (Italy) priorities list of contaminated sites: A new relative risk assessment procedure
No full textProgress in the study of glass-based systems as sealants for proton ceramic electrolysis cell assembly
Full text linkThis study compares a commercial boron-based glass and its composite, obtained by adding 5 wt% 3YSZ, with a
silica-based glass as sealants for joining AISI 441 ferritic stainless-steel interconnectors to BZCY622/NiOBZCY622 protonic ceramic half-cells. The boron-based glass and its composite exhibited lower glass transition
temperatures (500◦C–600 ◦C), making them well-suited for the operating range of PCECs. The composite
approach enabled tuning of the viscous flow behavior, softening temperature, and coefficient of thermal
expansion (CTE) while also enhancing the thermal stability. SEM-EDX characterization of samples joined with
the composite system confirmed no significant structural evolution after aging for 500 h at 600 ◦C in an air-steam
mixture (70 %–30 % vol.). Both the boron-based glass and its composite effectively relaxed stresses induced by
CTE mismatch between the joined layers and by the chemical expansion of the electrolyte, demonstrating
excellent thermal stability under severe cycling conditions in an air-steam mixture (70 %–30 % vol.)
Single-step fully 3D printed and co-sintered solid oxide fuel cells
No full textThe application of additive manufacturing technologies for the fabrication of functional ceramics has exhibited extraordinary potential for revolutionizing conventional manufacturing routes of electrochemical energy generators. The incorporation of 3D printing into the production strategy of Solid Oxide Cells (SOCs) allows their geometrical complexity to be increased through the hierarchical design of the systems, while simultaneously optimizing the ceramic manufacturing process, minimizing the upfront investment, and augmenting the manufacturing efficiency owing to the reduction in production steps. In this regard, the elaboration of multi-material 3D printing for the fabrication of entire SOC devices is required to achieve a fully automated production process. The current work presents and discusses the main technological and material challenges for the development of self-supported Solid Oxide Fuel Cells (SOFCs) fabricated in a single step by using hybrid multi-material 3D printing. The results on the fabrication of complete self-supported SOFCs are here presented with special attention to the most critical steps: the hybridization of stereolithography and robocasting 3D printing technologies and the co-sintering of a multilayered ceramic device. The electrochemical characterization of the printed and co-sintered cells validates the innovative approach, reaching a remarkable maximum power density above 250 mW cm−2 at 950 °C. This result, together with the developed hybrid technology, represents a step forward for further digitalization of the functional ceramic device manufacturing, more specifically, the SOC manufacturing process, leading to the fabrication of fully 3D printed monolithic SOFC stacks
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