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Effect of cenosphere fillers on mechanical strength and abrasive wear resistance of carbon–glass polyester composites
Full text linkFabric-reinforced hybrid polymer composites are present in almost every sector of modern life, and most essential areas of research in recent years have focused on glass–carbon fabric with filler material composites. Fabric and fillers are employed in strengthening polymer composites with the aim of improving their mechanical and tribological properties. The primary objective of this investigation was to investigate thetribological and mechanical properties of unfilled and cenosphere-filled carbon–glass-reinforced polyester composite systems, utilizing two types of fabric (glass and carbon) with cenosphere filler in varying weight fractions (0, 2.5, 5, 7.5, 10, and 12.5 wt.%) for both carbon fabric and the cenosphere. The abrasive wear characteristics were evaluated using a stainlesssteel wheel abrasion tester, utilizing silica sand as the abrasive material. Tests were performed at various distances (360–1800 m) and loads (12 N and 24 N). The results show that the wear rate of carbon–glass fabric-reinforced polyester composites differs significantly, with and without cenosphere fillers. Notably, the unfilled composites exhibit the highest wear volume loss, indicating a substantial improvement in wear resistance with the addition of cenospheres. The results reveal that in carbon–glass fabric-reinforced polyester composites, specific wear rate decreases when more cenospheres are loaded. The wear rate was successfully reduced by cenospheresunder silica sand as an abrasive. Compared to unfilled composites, the mechanical properties of filled composites exhibit superior performance. These variations were explained by examining the worn-out surfaces under an SEM and correlating the features observed with the mechanical properties.</jats:p
Comparação de técnicas de levantamento geométrico do património existente
No full textA reabilitação de edificações e estruturas antigas tem vindo a aumentar, mas muitas vezes a
informação disponível sobre as mesmas é escassa. A informação de construção inclui tanto elementos
geométricos como não geométricos. A integração de tecnologias pode facilitar o processo de obtenção
de informação, em especial nos elementos geométricos.
Esta dissertação explora as técnicas de levantamento geométrico que utilizam métodos não
invasivos para recolher dados detalhados das edificações, estruturas da envolvente. Estas técnicas
permitem gerar modelos digitais 3D a partir de nuvens de pontos que representam superfícies e podem
incluir propriedades como cores e texturas.
O objetivo principal da dissertação foi analisar as técnicas de levantamento geométrico
existentes e avaliar sua precisão através de aplicações práticas. A metodologia combinou a pesquisa
teórica com uma parte prática, utilizando diferentes equipamentos e técnicas em diversos casos de
estudo. A dissertação está organizada em seis capítulos que abordam desde o enquadramento teórico
até à análise dos resultados experimentais.
Foram abordadas e classificadas as técnicas de levantamento e as diversas tecnologias
existentes no momento, sendo comparadas cada uma das técnicas demostrando tanto os benefícios
como as suas limitações. Posteriormente, através de uma abordagem prática em diversos casos de
estudo, são analisados os resultados qualitativos e quantitativos obtidos e comparados com os de
outros autores.
Demonstrou-se a aplicabilidade de cada uma das técnicas de levantamento geométrico no
entanto, para a escolha da técnica mais adequada para se obter um modelo preciso e com qualidade,
é necessário considerar as características construtivas e as necessidades do levantamento a executar.
O Varrimento a Laser mostrou uma melhor precisão e consistência de resultados. O
Levantamento Fotogramétrico tem uma grande dependência das condições do local mostrando uma
variação de precisão não desprezável, no entanto é a técnica que apresenta a melhor relação custo benefício. Estas duas técnicas são as que conseguem por si só obter um levantamento completo de
todas as superfícies dos elementos que integram o espaço, ao contrário do Levantamento Tradicional
e o Levantamento por Satélite que apenas podem ser usados como ferramentas de apoio.The rehabilitation of old buildings and structures has been increasing, but the information
available about them is often scarce. Construction information includes both geometric and non geometric elements. The integration of technologies can facilitate the process of obtaining information,
especially regarding geometric elements.
This dissertation focuses on geometric surveying techniques that use non-invasive methods to
collect detailed data on buildings, structures, and their surroundings. These techniques enable the
generation of 3D digital models from point clouds that represent surfaces and may include properties
such as colors and textures.
The main objective of the dissertation was to analyze existing geometric surveying techniques
and evaluate their accuracy through practical applications. The methodology combines theoretical
research with a practical component, using different equipment and techniques in various case studies.
The dissertation is organized into six chapters, covering topics from the theoretical framework to the
analysis of experimental results.
The surveying techniques and the various technologies currently available are addressed and
classified, comparing each technique to highlight both their benefits and limitations. Subsequently,
through a practical approach in various case studies, the qualitative and quantitative results obtained
are analyzed and compared with those of other authors.
The applicability of each geometric surveying technique was demonstrated. However, selecting
the most appropriate technique to obtain a precise and high-quality model requires considering the
construction characteristics and the specific needs of the survey to be conducted.
Laser scanning showed better accuracy and consistency in results. Photogrammetric surveying
heavily depends on site conditions, displaying a non-negligible variation in accuracy; however, it offers
the best cost-benefit ratio. These two techniques are the only ones capable of independently providing
a complete survey of all the surfaces of the elements within the space. In contrast, traditional surveying
and satellite surveying can only be used as supporting tools
Sequência didática gamificada: um caminho para o ensino da lógica no ensino médio integrado no contexto da pandemia
Full text linkSocial anxiety in VR-CBT: transformative insights for college students
Full text linkOs problemas de saúde mental são um sério obstáculo para os estudantes universitários, tornando
as tarefas da vida quotidiana difíceis e stressantes, afetando negativamente as suas notas académi cas, competências sociais e até mesmo levando à dor física. A perturbação de ansiedade social,
um problema comum entre os estudantes universitários, leva o indivíduo a evitar interagir com
outros e a ter um medo constante de julgamentos negativos. As intervenções digitais têm mostrado
resultados promissores para a prestação de cuidados de saúde mental a estudantes universitários,
particularmente através da integração da tecnologia de realidade virtual (VR) para simular cenários
imersivos da vida real. Neste trabalho, exploramos como um jogo baseado em VRCBT (Cognitive
Behavioral Therapy de Realidade Virtual) pode transmitir eficazmente conceitos e práticas de
CBT, ao mesmo tempo que analisamos as implicações e os desafios de design da criação de uma
experiência transformadora para o jogador. Para tal, doze estudantes universitários com idades
compreendidas entre os 18 e os 25 anos foram recrutados para participar num estudo no qual
testaram o artefacto e responderam a questionários pré e pós-intervenção, juntamente com uma
entrevista semiestruturada no final. Avaliámos o ganho de conhecimento do participante em CBT,
o ganho de literacia em saúde mental e a experiência de jogo. Os resultados demonstraram uma
experiência positiva para todos os participantes, tendo sido observado um aumento tanto no con hecimento sobre a CBT como na literacia em saúde mental, sugerindo que esta abordagem foi
capaz de aumentar o envolvimento, a literacia em saúde mental e a aplicação prática da CBT.
Embora sejam necessários refinamentos no design e na metodologia, especialmente no equilíbrio de
alguns elementos do jogo e na avaliação do efeito da intervenção a longo prazo, este estudo con tribui para a compreensão do potencial do papel de VRCBT para a ansiedade social num contexto
universitário.Mental health issues are a serious obstacle to college students, making everyday life tasks difficult
and stressful, thus negatively affecting student’s academic grades, social skills and even leading to
physical pain. Social anxiety disorder, a common issue amongst college students, leads the individ ual to avoid interacting with other people and to possess an ongoing fear of negative judgements.
Digital interventions have shown promising results for providing mental health care to college stu dents, particularly through the integration of virtual reality (VR) technology to simulate immersive
real-life scenarios. In this work, we explore how a game based on VRCBT (Virtual Reality Cogni tive Behavioral Therapy) can effectively convey CBT concepts and practices while also analysing
the design implications and challenges of creating a transformative player experience. To this end,
twelve college students aged 18-25 were recruited to participate in a study where they tested the
artifact and completed pre and post intervention questionnaires, along with a semi-structured
interview at the end. We evaluated the participant’s knowledge gain in CBT, mental health liter acy gain, and gameplay experience. The results showed a positive experience for all participants,
with an observed increase in both CBT knowledge and mental health literacy, suggesting that
this approach was capable of enhancing engagement, mental health literacy, and practical CBT
application. While refinements in design and methodology are required, especially in balancing
some game elements and evaluating the intervention’s effect long term, this study contributes to
understanding the potential of VRCBT’s role for social anxiety in a college context
A influência da remuneração na liderança e desempenho dos colaboradores das unidades hoteleiras: aplicação à Ilha da Madeira
Full text linkAtualmente, ter colaboradores eficientes e focados no trabalho, capazes de prestar
os serviços com qualidade, é um fator que determina o sucesso das empresas. Na verdade,
a liderança possui um papel relevante nos resultados obtidos pelas empresas,
nomeadamente através do apoio aos colaboradores e do incentivo à adoção de práticas
mais eficazes. Contudo, o tipo liderança e o desempenho dos colaboradores podem ser
afetados, pela remuneração que estes recebem. Até onde foi possível analisar, a maioria
das investigações sobre a remuneração, liderança e desempenho dos colaboradores na
hotelaria, preocupa-se em demonstrar como os estilos de liderança têm impacto no
desempenho dos colaboradores. Outros estudos determinaram que a remuneração e os
incentivos têm um impacto significativo nas empresas. Porém, não demonstram a relação
que existe entre a remuneração, a liderança e o desempenho dos colaboradores, tal como
o seu impacto, em unidades hoteleiras de categorias distintas. Assim, esta investigação
tem como principal objetivo avaliar de que forma é que a remuneração está relacionada
com a liderança e o desempenho dos colaboradores das unidades hoteleiras, mais
concretamente da Ilha da Madeira. Neste sentido, foi realizado um inquérito por
questionário, aplicado a 365 colaboradores das unidades hoteleiras da região. Os
resultados do estudo demonstraram que os estilos de liderança transformacional e
transacional influenciam positivamente o desempenho dos colaboradores; a perceção da
remuneração influencia estes dois estilos de liderança; contudo a perceção da
remuneração não influencia o desempenho dos colaboradores.
Este estudo fornece contribuições para a literatura acerca da influência da
remuneração nos estilos de liderança transformacional e transacional e no desempenho
dos colaboradores das unidades hoteleiras da Ilha da Madeira, uma vez que há falta de
estudos empíricos relacionados com esta temática.Currently, having efficient and focused employees who are capable of providing
high-quality services is a key factor that determines the success of companies. In fact,
leadership plays a relevant role in the results achieved by organizations, particularly
through the support provided to employees and the encouragement of adopting more
effective practices. However, both leadership style and employee performance can be
affected by the remuneration they receive. As far as it has been possible to analyze, most
research on remuneration, leadership, and employee performance in the hospitality
industry focuses on demonstrating how leadership styles impact employee performance.
Other studies have found that remuneration and incentives have a significant impact on
organizations. Nevertheless, they do not demonstrate the relationship between
remuneration, leadership, and employee performance, nor their impact on hotels of
different categories.
Therefore, the main objective of this research is to assess how remuneration is
related to leadership and employee performance in hotel units, specifically in Madeira
Island. To this end, a questionnaire survey was conducted with 365 employees from hotel
units in the region. The results of the study showed that transformational and transactional
leadership styles positively influence employee performance; the perception of
remuneration influences these two leadership styles; however, the perception of
remuneration does not influence employee performance.
This study contributes to the literature on the influence of remuneration on
transformational and transactional leadership styles and on employee performance in
hotel units in Madeira Island, given the lack of empirical studies related to this topic
Transforming education: pedagogical innovation in diversifed contexts
Full text linkThe research presented follows an
interpretative, organized, and systematic pro cess aimed at the emergence of concepts and
practices capable of deepening the understan ding of Pedagogical Innovation (PI) across
diverse formal, non-formal, and informal
learning environments. Conceptually, Peda gogical Innovation is analyzed within a post modern context, where epistemological and
axiological challenges increasingly impact
education, particularly schools, which often
remain anchored in practices that struggle
to foster deep and meaningful learning of an
ever more plural, intersubjective, and complex
knowledge landscape. The research employs
an interpretative meta-synthesis approach,
analyzing 107 dissertations and theses in Edu cational Sciences—Pedagogical Innovation,
defended at the University of Madeira betwe en 2007 and 2015. All studies analyzed were
qualitative, and the meta-synthesis utilized a
meta-ethnographic methodology. Through
an inductive process, the research structured
successive interpretative syntheses in its first
stage, identifying 1,285 conceptual segments
that reflect ideas, concepts, or topics relevant
to the theme. In the second stage, involving
the translation of primary studies (1st Level
of Synthesis), 42 significant key concepts were
identified. This process culminated in the
third stage—Synthesis of Translations (2nd
Level of Synthesis)—which led to the forma tion of five macro-conceptual categories: the
construction of competences, teaching profes sionalism, students’ learning experiences, the
nature of praxis, and instrumental resources.
The conclusions reveal that Pedagogical Innovation constitutes a complex and multidimen sional phenomenon rooted in conscious and
critical processes of change. These processes
emphasize students’ capacities and attitudes,
linked to pedagogical practices grounded in
constructivist epistemological frameworks.
Additionally, the findings highlight an inno vative praxis that remains deeply localized,
limited to micro-intervention environments.
The potential of ICT is noted as a valuable tool
for fostering new learning approaches under
specific conditions. Recommendations are directed at educational institutions, urging them
to act as facilitators of collaborative cultural
spaces, and at policymakers, advocating for
strategies to reduce bureaucratic constraints
and enable genuine school autonomy
2024 U.S. presidential elections: an event study for U.S. and non-U.S. fossil fuel and renewable listed firms
Full text linkThis study examines the short-term market effect of Donald Trump’ victory in the 2024 US presidential election
on largest US and non-US listed worldwide fuel fossil and renewable firms. Employing an event study meth odology, we observe a negative and statistically significant stock price reaction for worldwide renewable listed
firms. An analysis by economic zones reveals the existence of negative abnormal returns for renewable energy
firms in the US, Europe, India and in the rest of the world. In the case of China, abnormal returns are not sta tistically significant. With respect to worldwide fossil fuel listed firms, abnormal returns are generally not sta tistically significant. However, regarding US firms, we observe positive and statistically significant abnormal
returns. These abnormal returns are explained by the change of US energy policy (pro-oil and gas policy) and the
expected cut in subsidies and lower profitability of investments in green energies. Finally, our study provide
insight into which firm-specific characteristics emerge as value drives around US presidential elections. The
results show that despite the change in environmental policy in the US, favourable to fossil energy, the stock
markets reward firms with high environmental ratings. Overall, our results indicate that 2024 US presidential
election, for implying a change in US energy policy, has relevant policy implications for energy listed firms
Artefactos de mediação semiótica e aprendizagem matemática: um robô em enfermarias COVID
Full text linkThe experiences of intimacy, commitment and passion throughout life: a qualitative study of older gay and bisexual men
Full text linkAbstract
Romantic relationships during aging can have diverse implications for reducing mental health problems, mortality rates, and the prevention and management of chronic diseases in older adults. However, little is known about the relational dynamics of gay and bisexual (GB) older men. The experiences of romantic relationships throughout the life cycle of Portuguese GB older people and their relationship with identity development were evaluated using Sternberg’s triangular theory of love. A total of 23 semi-structured interviews were carried out with older community-dwelling Portuguese GB (60 + years old) using the lifeline, which were later analyzed using thematic analysis. The results suggested that experiences of greater relational maturity in older GB people corresponded to phases of greater identity integrity. These older adults gradually experienced more complex levels of love, starting from more passionate love relationships (confusion/comparison phase) to romantic love relationships (tolerance/acceptance phase) and later companionate love relationships (synthesis phase). These relational changes accompanied broader psychosocial changes in gaining rights and freedoms in Portugal. Older gay and bisexual men are capable of experiencing complex forms of love, just like their heterosexual counterparts. However, they tend to reach these stages later in life due to the significant obstacles imposed by the psychosocial context on the development of their identities.</jats:p