Publicações - engenharias
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PÉRICLES JOSÉ PIRES;
Victor Matheus Batista Nascimento Sedovim;
Ricardo Mendes Junior;
Maria do Carmo Duarte Freitas
Palavra-chave:
competência informacional;
Tecnologia digital;
percepções e visões estudante
Áreas do conhecimento:
Engenharias; Engenharia de Produção; Gestão da Informação;
Engenharias; Engenharia de Produção; Gerência de Produção; Gestão do Conhecimento
resumo ...
(en)
The study presents an emerging topic in the field of Information Science: the relationship between students' digital competence and their use of digital technologies for learning. The study focuses on understanding how information competence influences students' intention to use digital technology in accessing information for their learning. The objective is to propose a model that explains this potential relationship, drawing on theoretical support from technology use and acceptance models. To this end, the research adopts a descriptive approach with a quantitative methodology, applying 280 online questionnaires to undergraduate students from the Administration, Economics, Accounting, and Information Management programs at the Federal University of Paraná. Statistical tests and multivariate data analysis were conducted to assess the cause-effect relationships between the constructs in the proposed model. Structural equation modeling, using SmartPLS software version 4.1, provided the statistical foundation for analysis. The results indicated relationships between elements of information competence and the dependent variable, intention to use. The tested hypotheses revealed that perceived ease of use in information searching, handling, and utilization are significant. However, the direct relationship between perceived usefulness and information competence was not substantiated; it was only validated when indirectly mediated by ease of use. In conclusion, the easier it is to use the obtained information, the stronger the intention to use digital technologies for acquiring such information.
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La investigación presenta un tema emergente en el campo de la Ciencia de la Información: la relación entre la competencia digital de los estudiantes y el uso de tecnologías digitales para el aprendizaje. El enfoque del estudio es comprender cómo la competencia en información influye en la intención de los estudiantes de utilizar tecnologías digitales en el acceso y uso de la información para su aprendizaje. El objetivo es proponer un modelo que explique esta posible relación, utilizando como soporte teórico los modelos de uso y aceptación de tecnologías. Para ello, se adopta un enfoque descriptivo con metodología cuantitativa, mediante la aplicación de 280 cuestionarios en línea a estudiantes de pregrado de los programas de Administración, Economía, Contabilidad y Gestión de la Información de la Universidad Federal de Paraná. La realización de pruebas estadísticas y el análisis multivariado de los datos permitieron examinar las relaciones de causa y efecto entre los constructos del modelo propuesto. Como soporte estadístico, se empleó la técnica de modelización de ecuaciones estructurales, utilizando el software SmartPLS versión 4.1. Los resultados indicaron relaciones significativas entre los componentes de la competencia en información y la variable dependiente intención de uso. Las hipótesis probadas evidenciaron que la facilidad de uso percibida en los procesos de búsqueda, tratamiento y utilización de la información es significativa. Sin embargo, la relación directa entre la utilidad percibida y la competencia en información no fue confirmada, siendo validada únicamente de forma indirecta a través de la facilidad de uso.
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A investigação apresenta um tema emergente no campo da Ciência da Informação: a relação entre a competência digital do estudante com o uso de tecnologias digitais para aprendizagem. O foco do trabalho é entender como a competência em informação influencia a intenção de uso da tecnologia digital pelos estudantes quanto as informações para a sua aprendizagem. O objetivo é apresentar um modelo que explique esta possível relação, utilizando como suporte teórico modelos de uso e aceitação de tecnologia. Para tanto, ela adota um enfoque descritivo com abordagem quantitativa no seu desenvolvimento, com a aplicação de 280 questionários online com estudantes de graduação dos cursos de Administração, Economia, Contabilidade e Gestão da Informação da Universidade Federal do Paraná. A realização de testes estatísticos e a análise multivariada de dados analisou as relações de causa-efeito entre os construtos do modelo proposto na investigação. Como suporte estatístico, empregou-se a técnica de modelagem de equações estruturais, com o uso do software SmartPLS versão 4.1. Os resultados indicaram a relação dos itens da competência em informações com a variável dependente intenção de uso. As hipóteses testadas indicaram que a facilidade de uso percebida quanto ao tratamento de busca e uso da informação são significativos. No entanto, não foi comprovada a relação direta entre a utilidade percebida e a competência em informação, somente comprovada quando está relacionada indiretamente através a facilidade de uso. Pode-se concluir que quanto maior for a facilidade de uso das informações obtidas maior será a intenção de uso de tecnologias digitais.
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RICHARDSON, MARK I.;
KITE, EDWIN S.;
ANSARI, SAMANEH;
FAN, BOWEN;
RAMIREZ, RAMSES;
MOHSENI, HOOMAN;
MISCHNA, MICHAEL A.;
HECHT, MICHAEL H.;
STEELE, LIAM J.;
Felix Sharipov
Palavra-chave:
Aerothermodynamics;
External flow
Áreas do conhecimento:
Engenharias; Engenharia Mecânica; Fenômenos de Transporte; Dinâmica dos Gases
resumo ...
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Ana Paula Cristina dos Santos Ojea;
Miguel Mansur Aisse;
HERNÁNDEZ, ORLANDO ANTONIO DUARTE;
Thiago Marenda
Palavra-chave:
biogas;
Codigestão anaeróbia;
Lodos de ETEs;
metano;
Resíduos orgânicos
Áreas do conhecimento:
Engenharias; Engenharia Sanitária; Tratamento de Águas de Abastecimento e Residuárias; Processos Simplificados de Tratamento de Águas;
Engenharias; Engenharia Sanitária; Saneamento Básico; Residuos Sólidos, Domésticos e Industriais
resumo ...
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Ana Carolina Moreno Nunes;
Cézar Augusto Casagrande;
Lidiane Fernanda Jochem;
Marcelo Henrique Farias de Medeiros;
Ricardo Pieralisi
Palavra-chave:
concreto com fibras;
Corrosão;
durabilidade do concreto
Áreas do conhecimento:
Engenharias; Engenharia Civil; Inovação
resumo ...
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KUSS, CINTIA PEREIRA;
Leandra Ulbricht;
SCHUMACHER, KLAUS;
Ripka, Wagner L.
Palavra-chave:
Automated body composition analysis;
Computed Tomography;
Comparison of medical image segmentation methods
Áreas do conhecimento:
Engenharias; Engenharia Biomédica; Engenharia Médica; Biomateriais e Materiais Biocompatíveis;
Engenharias; Engenharia de Produção; Engenharia do Produto; Saúde Pública
resumo ...
Body composition (BC) assessment by computed tomography (CT) at the level of the third lumbar vertebra (L3) is considered the gold standard for evaluating muscle and adipose compartments. However, manual segmentation is time-consuming and impractical for large data sets. This study aimed to compare the automated method, Identificação Automatizada da Composição Corporal (IACC), with manual segmentation performed using 3D Slicer. This retrospective cross-sectional study included 126 participants, each contributing one single axial CT slice at the L3 level, obtained from routine clinical CT scans acquired between November 2023 and January 2025. Manual segmentations were performed in 3D Slicer by a trained evaluator and validated by an experienced radiologist. The IACC automatically identified the L3 level and segmented skeletal muscle (MUSCLE), subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT). Analyses included intra- and inter-rater reproducibility (ICC, Dice coefficient), Pearson correlation, agreement (ICC), and Bland–Altman plots. Results The mean analysis time was approximately 5 min per scan with IACC, compared with 25–30 min using the manual method. Intra-rater reproducibility was excellent (ICC > 0.99), and inter-rater agreement demonstrated high Dice coefficients for SAT (0.982), skeletal muscle (0.940), and VAT (0.932). Concordance between methods was high for SAT (ICC = 0.932) and VAT (ICC = 0.958), and good for skeletal muscle (ICC = 0.784), all with Pearson’s r > 0.97. Bland–Altman analysis showed minimal mean bias for VAT (− 0.35 cm2) and small variability for SAT, indicating excellent agreement for adipose tissue compartments. In contrast, skeletal muscle presented greater disagreement, with a larger negative bias and wider limits of agreement, reflecting higher variability in automated measurements. IACC demonstrated high accuracy and efficiency for automated segmentation of SAT and muscle, substantially reducing analysis time compared to manual segmentation. Although greater variability was observed for skeletal muscle measurements, the tool shows promise for use in large-scale population studies and potential clinical applications, particularly, where rapid and standardized analyses are required.
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Jóse Viriato Coelho Vargas;
CARDOZO-FILHO, L.;
giuliana sardi venter;
ORDONEZ, J.C.;
Henrique Pope Guerra;
alexandre moura da silveira;
Dhyogo Miléo Taher;
MATIOLO, C. H.;
L. S. Martins;
Stephan Hennings Och;
Diogo Berta Pitz;
André Bellin Mariano
Palavra-chave:
Aluminum hydroxide;
sodium hydroxide;
Aluminum Scrap
Áreas do conhecimento:
Engenharias; Engenharia Mecânica; Engenharia Térmica; Aproveitamento da Energia
resumo ...
This work introduces a sustainable electricity generation system driven by green hydrogen, produced from aluminum and water. The system consists of a hydrogen batch reactor, a buffer tank, a booster, a compressor, a storage tank and a proton exchange membrane fuel cell (PEMFC) stack, mounted on a car trailer for compacity and mobility. The Alkaline Aqueous Redox Reaction of Aluminum (AARRA) allows for the production of H2 to supply the PEMFC stack. Since residual aluminum from a well-established recycling chain, seawater or degraded water could be utilized, the system is expected to be fully sustainable. A prototype was built in the laboratory and system characterization was carried out considering the hydrogen production, storage, and power generation with the PEMFC stack that uses the green hydrogen generated in the reactor as fuel. The prototype main components were built with AISI 316 stainless-steel to prevent the corrosion promoted by the alkaline solution and hydrogen embrittlement, guaranteeing the system durability. The results show that the system was capable of generating up to 20.5 g of hydrogen in each batch, corresponding to a hydrogen yield of 81% when compared to the stoichiometric value. Experimental power and polarization curves characterizing the operation of a 5-kW Horizon PEMFC stack were obtained, which showed good qualitative and quantitative agreement with the nominal curves provided by the fuel cell manufacturer. The produced H2 had the necessary purity to supply the PEMFC stack up to 90% of its maximum nominal power with no need of extra energy consumption for H2 purification, which is an advantage in comparison to other green H2 production methods, such as electrolysis that requires extra-energy consumption for H2 dehumidification. A prototype of an electric vehicle (EV) range extender (REX) was built with the proposed system and tested, showing that the EV nominal range was increased by 16%, accounting for 61.5 km of vehicle autonomy. Hence, possible future direct applications include electric vehicles, all electric ships and stationery distributed power generation.
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FERNANDO, RAMOS;
BESSA, MARCO;
Maria do Carmo Duarte Freitas
Palavra-chave:
gestão da informação;
Competência Docente Digital;
PALOP;
Formação Continuada
Áreas do conhecimento:
Engenharias; Engenharia de Produção; Gerência de Produção; Gestão do Conhecimento;
Engenharias; Engenharia de Produção; Gestão da Informação
resumo ...
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LOPES, SOFIA X.;
NASCIMENTO, CARLOS F. G.;
FERNANDES, IGOR V.;
Marcelo Henrique Farias de Medeiros;
MELO NETO, ANTÔNIO A.
Palavra-chave:
expanded vermiculite;
Drying shrinkage;
Alkali-activated slag
Áreas do conhecimento:
Engenharias; Engenharia Civil; Inovação
resumo ...
The growing need to reduce CO2 emissions has encouraged the use of alkali-activated materials as sustainable alternatives to Portland cement. However, these binders are often susceptible to significant autogenous and drying shrinkage, which can compromise dimensional stability and durability. This study evaluates the influence of expanded vermiculite (EV) on the autogenous and drying shrinkage behavior of alkali-activated slag mortars. Mixtures containing 5%, 10%, and 15% EV were produced under dry, 100%, and 200% pre-saturation conditions, with a constant binder-to-aggregate ratio of 1:2 and a (w/b) ratio of 0.48. Physical and mechanical performance was analyzed through consistency, air content, density, compressive strength, capillary absorption, and microtomography tests. The results indicated that increasing the vermiculite content reduced the bulk density by up to 9.1% and increased the incorporated air content, which in turn decreased compressive strength by up to 31.4%. Capillary water absorption rose markedly in mixtures with 15% EV at 200% pre-saturation after 90 min. Autogenous shrinkage decreased by 66.4% in mixtures with dry EV, and 200% pre-saturation produced an additional 36.1% reduction. These results demonstrate that the moisture state of EV strongly governs shrinkage and pore connectivity in alkali-activated mortars. Controlled internal curing enhances dimensional stability while limiting strength losses when EV saturation and w/b are properly balanced. A forthcoming life-cycle assessment will quantify the environmental trade-offs of incorporating EV as an internal-curing agent.
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Bruno Xavier Souza;
Maria Carolina Maziviero
Palavra-chave:
transição energética brasileira;
mudanças climáticas;
Belo Monte
Áreas do conhecimento:
Outros; Ciências Ambientais; ciência ambiental;
Ciências Sociais Aplicadas; Planejamento Urbano e Regional; Serviços Urbanos e Regionais; Estudos da Habitação;
Engenharias; Engenharia Elétrica; Telecomunicações
resumo ...
(en)
In a contemporary context marked by increasing debate on sustainability, energy, and climate justice, this article examines the divergent views surrounding the implementation of the Belo Monte Hydroelectric Power Plant. The perspectives of Indigenous peoples and riverine communities, whose traditional territories are located near the Xingu River, are contrasted with the technical approaches of the Federal Government, which promotes the expansion of the national electric system while frequently overlooking socio-environmental impacts. The plant exemplifies a hegemonic model of development that privileges an urban minority at the expense of the survival of traditional populations. By discussing the technical differentials of hydropower in relation to other energy sources, the analysis reveals Belo Monte as an expression of energy neocolonialism, highlighting the undermining of climate justice and the credibility of Brazil’s energy transition. The research adopts a methodological approach that combines historical, energy-related, and political analysis, enabling an integrated understanding of the project’s context. This methodology underscores the importance of the 1989 Altamira Gathering and presents the narratives of the federal government, the Assurini people, and riverine communities, addressing their differing views on the plant. By exploring the dilemma of hydropower in comparison with other energy sources, the article fosters a critical dialogue on the impacts and implications of the Belo Monte Hydroelectric Power Plant, ensuring that the relevance of the topic remains central to contemporary debates.
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En un contexto contemporáneo de creciente debate sobre la sostenibilidad, la energía y la justicia climática, este artículo examina las visiones divergentes en torno a la implementación de la Central Hidroeléctrica de Belo Monte. Las perspectivas de los pueblos indígenas y de las comunidades ribereñas, cuyos territorios tradicionales se encuentran próximos al río Xingu, se contraponen a los enfoques técnicos del Gobierno Federal, que promueve la expansión del sistema eléctrico nacional, a menudo ignorando los impactos socioambientales. La central ejemplifica un modelo hegemónico de desarrollo que privilegia a una minoría urbana en detrimento de la supervivencia de las poblaciones tradicionales. Al analizar las diferencias técnicas de la energía hidroeléctrica frente a otras fuentes energéticas, el estudio revela a Belo Monte como una expresión de neocolonialismo energético, evidenciando el deterioro de la justicia climática y de la credibilidad de la transición energética brasileña. La investigación adopta un enfoque metodológico que combina el análisis histórico, energético y político, lo que permite una comprensión integrada del contexto del proyecto. Esta metodología destaca la importancia del Encuentro de Altamira de 1989 y presenta las narrativas del gobierno federal, del pueblo Assurini y de las comunidades ribereñas, abordando sus diferentes visiones sobre la central. Al explorar el dilema de las centrales hidroeléctricas en comparación con otras fuentes energéticas, el artículo promueve un diálogo crítico sobre los impactos e implicaciones de la Central Hidroeléctrica de Belo Monte, garantizando que la relevancia del tema se mantenga en las discusiones contemporáneas.
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Em um contexto atual de crescente discussão sobre sustentabilidade, energia e justiça climática, este artigo examina as visões divergentes sobre a implementação da Usina Hidrelétrica de Belo Monte. As perspectivas de povos indígenas e ribeirinhos, cujos territórios tradicionais estão próximos ao rio Xingu, são confrontadas com as abordagens técnicas do Governo Federal, que promove a expansão do sistema elétrico nacional, frequentemente ignorando os impactos socioambientais. A usina exemplifica um modelo hegemônico de desenvolvimento que privilegia uma minoria urbana em detrimento da sobrevivência das populações tradicionais. Ao discutir os diferenciais técnicos da hidroeletricidade frente a outras fontes energéticas, a análise revela Belo Monte como uma expressão de neocolonialismo energético, evidenciando o comprometimento da justiça climática e da credibilidade da transição energética brasileira. A pesquisa adota uma abordagem metodológica que combina análise histórica, energética e política, permitindo uma compreensão integrada do contexto do projeto. Essa metodologia destaca a importância do Encontro de Altamira de 1989 e apresenta as narrativas do governo federal, do povo Assurini e das comunidades ribeirinhas, abordando suas diferentes visões sobre a usina. Ao explorar o dilema das hidrelétricas em comparação com outras fontes energéticas, o artigo promove um diálogo crítico sobre os impactos e implicações da UHE Belo Monte, garantindo que a relevância do tema se mantenha nas discussões contemporâneas.
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SIGNORI-IAMIN, GIOVANA;
MARQUEZ, RONALD;
BASTIDA, GABRIELA A.;
TARRÉS, QUIM;
Alexandre Ferreira Santos;
DELGADO-AGUILAR, MARC
Palavra-chave:
nanocelulose;
Inteligência Artificial;
Modelagem
Áreas do conhecimento:
Engenharias; Tecnologia Química; Papel e Celulose;
Engenharias; Engenharia Química; Operações Industriais e Equipamentos para Engenharia Química;
Engenharias; Engenharia Química; Processos Industriais de Engenharia Química; Processos Biotecnológicos
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Despite growing interest in enzymatic fiber modification, the impact of high-consistency enzymatic refining on the mechanical performance of paper remains unexplored. Unlike conventional low-consistency systems, high-consistency enzymatic refining offers a more energy-efficient and industrially scalable pathway for surface modification of cellulose fibers. This study investigates, under industrially relevant conditions, how high-consistency enzymatic refining of bleached kraft eucalyptus pulp with endoglucanases can support the rational design of fiber-based bioproducts. Pulp consistency (3–15 wt% ), enzyme dosage (0–300 mg/kg), and treatment time (15–60 min) were systematically varied. High-consistency enzymatic refining significantly enhanced mechanical performance: breaking length increased up to 89% and internal bonding up to 387%, without substantial freeness reduction. To enable predictive design and process optimization, machine-learning models were developed first based on process variables (consistency, time, dosage). LightGBM model achieved the best results with high predictive accuracy for property prediction (R2 up to 0.955). To overcome data scarcity, a physics-informed generative augmentation strategy was implemented that incorporates freeness to generate 30 synthetic datapoints. The augmented dataset enhances predictive performance, validating the quality of the synthetic data. A physics-informed Gaussian process regression model was used to extrapolate performance at 400 mg/kg enzyme dosage, and a targeted experiment confirmed its prediction. The results suggest that high-consistency enzymatic refining enhances interfiber bonding through the generation of nanoscale fibrillar elements at the surface, influencing the final bonding of the sheet. Altogether, high-consistency enzymatic refining coupled with predictive modeling shows as a viable pathway towards producing all-cellulose materials with improved mechanical properties, while reducing energy consumption.
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