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Glycerol removal through dry purification of biodiesel produced from waste cooking oils using biomass-based adsorbents
No full textMestrado de dupla diplomação com a UTFPR, Universidade Tecnológica Federal do ParanáThe great demand for renewable energy sources has increased interest in biofuels in particular, with biodiesel being a viable alternative for replacing conventional diesel. Biodiesel is usually produced using vegetable oils, including waste cooking oils (WCOs), through a transesterification process. However, this process generates by-products such as glycerol, which needs to be removed to guarantee the quality of the biodiesel.
Purification is mostly done by wet washing, which generates large quantities of effluent. A possible alternative is the dry purification process, namely through adsorption which can be carried out using natural adsorbents derived from agro-industrial waste. This study therefore evaluated the removal of glycerol from biodiesel using adsorbents produced from several sources of agro-industrial wastes such as almond shells, rice husks, olive pits and walnut shells. For this purpose, WCO was collected, filtered and characterised to analyse acidity, free fatty acid profile and density. Biodiesel was then produced via transesterification by the ethanolic route, using a ratio of 1:7.5 oil/alcohol and 0.5 wt% of sodium hydroxide as a catalyst, at 30 °C. The content of 0.16 wt% of free glycerol in crude biodiesel was determined, and purification was necessary to meet the established standards specification, which require values below 0.02 wt%, according to EN 14105/14016 and ASTM D6584 norms. The adsorbents were used in natural form and with physical activation at 800 °C for 60 minutes, totalling eight materials for testing. Analyses were carried out to determine the point of zero charge, Fourier transform infrared spectroscopy, textural properties, thermogravimetric analysis and scanning electron microscopy. A preliminary test was carried out with 3% adsorbent at 25 °C for 360 min, and the natural materials showed the best removal performance. Hence, ricehusk, with 54% removal, and walnut husk, with 51.03%, were chosen to carry out the adsorption studies. The kinetic studies were done at three temperatures (25 °C, 35 °C and 45 °C), reaching equilibrium in approximately 480 min. The results indicated that the pseudo-second order model best described the process, suggesting that adsorption was controlled by chemical interactions between glycerol and the active sites of the adsorbent. The final concentration of free glycerol was approximately 0.05 wt% a temperature of 45°C. The adsorption isotherms were carried out by varying the adsorbent concentration between 3% and 10% at 45 °C for 480 min and showed that the data best fitted the Freundlich model, indicating a heterogeneous surface and the formation of multiple adsorbate layers. Finally, even though the materials did not allow the achievement of the value established by the standards, the studied adsorbents revealed great potential for in glycerol removal from biodiesel. Further studies are needed to: optimise the adsorption conditions, namely regarding temperature, add multiple steps in the adsorption process, or combine commercial and natural adsorbents
Innovative Applications of Artificial Neural Networks in Tax Forecasting
Get PDFThe importance of forecasting tax revenues is vital for economic planning and financial sustainability in Mozambique. The study addresses this topic by exploring the potential of Artificial Neural Networks (ANNs) to improve such predictions. The central problem is the limitation of conventional methods in capturing the complexity of fiscal data. The objective is to develop an ANN model that incorporates historical data and economic factors, providing a mixed methodology that enriches the analysis with qualitative and quantitative data. The rationale for adopting ANNs lies in their superior modeling and prediction capabilities in large and complex data environments. The results achieved demonstrate that ANNs can predict tax revenues with greater accuracy, surpassing traditional models. The conclusion points to the ANN as a valuable tool for tax authorities, enhancing efficiency in collection and contributing to the country's fiscal stability.A importância da previsão das receitas fiscais é vital para o planeamento econômico e sustentabilidade financeira em Moçambique. Este estudo aborda este tópico explorando o potencial das Redes Neurais Artificiais (RNAs) para melhorar tais previsões. O problema central é a limitação dos métodos convencionais em captar a complexidade dos dados fiscais. A razão para a adoção de RNAs reside na sua superior capacidade de modelação e previsão em ambientes de dados grandes e complexos. Os resultados obtidos demonstram que as RNAs podem prever as receitas fiscais com maior precisão, superando os modelos tradicionais. A conclusão aponta para a RNA como uma ferramenta valiosa para as autoridades fiscais, aumentando a eficiência na cobrança e contribuindo para a estabilidade fiscal do país
Digitalização de ativos industriais baseados em asset administration shells
Get PDFMestrado de dupla diplomação com a Universidade Tecnológica Federal do ParanáImpulsionados por novas tecnologias digitais, o desenvolvimento em sistemas de manufatura industrial está transformando os métodos tradicionais de operação adotados pelas empresas, otimizando os processos produtivos e a capacidade de inovação. A implementação destas tecnologias permitiu a digitalização de ativos industriais, possibilitando o monitoramento em tempo real, a análise preditiva e a tomada de decisões mais rápidas quando comparadas às tecnologias anteriores. Assim, emergindo na Indústria 4.0, o Asset Administration Shell aparece como uma forma de representação digital de um ativo, informando suas características técnicas e de identificação, bem como seus dados operacionais, por meio de uma estrutura de elementos modulares e hierárquicos, garantindo desse modo a padronização de componentes e a interoperabilidade entre sistemas. Neste trabalho será apresentada uma abordagem baseada em um cenário real de linha de montagem automotiva, com o intuito de implementar e digitalizar os equipamentos de medição geométrica presentes na fábrica, utilizando os conceitos e normas estabelecidos pelo Asset Administration Shell. Com suporte da ferramenta de interface gráfica AASX Package Explorer, será desenvolvido o modelo passivo do ativo e, posteriormente, o modelo reativo, este que utilizará o framework FastAPI para o gerenciamento em tempo real dos dados obtidos junto ao modelo da estrutura. Os desafios enfrentados e os resultados obtidos no estudo serão discutidos de forma crítica, relacionando-os com as tecnologias atuais aplicadas no cenário industrial.Driven by new digital technologies, developments in industrial manufacturing systems are transforming the traditional operating methods adopted by companies, optimizing production processes and innovation capacity. The implementation of these technologies has made it possible to digitize industrial assets, enabling real-time monitoring, predictive analysis and faster decision-making compared to previous technologies. Emerging in Industry 4.0, the Asset Administration Shell appears as a form of digital representation of an asset, informing its technical and identification characteristics, as well as its operational data, through an architecture of modular and hierarchical elements, ensuring the standardization of components and interoperability between systems. This paper will present an approach based on a real automotive assembly line scenario, with the purpose of implementing and digitizing the geometric measuring equipment present in the factory, using the concepts and standards established by the Asset Administration Shell. With the support of the AASX Package Explorer graphical interface tool, the passive model of the asset will be developed, followed by the reactive model, which will use the FastAPI framework for real-time management of the data obtained alongside the model. The challenges faced and the results obtained in the study will be discussed critically, relating them to the theories and methods used
Efeitos da electroestimulação na pessoa submetida a artroplastia total do joelho: uma scoping review
Get PDFO presente trabalho além da descrição e reflexão sobre o percurso de aquisição de competências de Enfermeiro Especialista em Enfermagem de Reabilitação, contempla uma componente investigativa sobre uma estratégia complementar na reabilitação das pessoas submetidas a artroplastia total do joelho. A artroplastia total do joelho é uma cirurgia comum em ortopedia, que ocorre maioritariamente devido a processos de osteoartrose. O pós-operatório pode ser desafiador, tendo o enfermeiro especialista em Enfermagem de Reabilitação um papel valioso, de forma a colmatar a espectável dor, diminuição da força muscular e dificuldade na execução das atividades de vida diárias no pós-operatório.
Objetivo: Mapear as evidências científicas sobre os efeitos da electroestimulação na pessoa submetida a artroplastia total do joelho. Métodos: Realização de uma scoping review tendo em conta a metodologia de Joanna Briggs Institute. Pesquisa nas bases de dados PubMed, Scielo, EBSCOhost e PEDro, tendo em conta os critérios de inclusão.
Resultados: Foram identificadas sessenta e três publicações sendo incluídas nesta análise sete. Demostrou-se que a electroestimulação apresenta benefícios principalmente a nível
da ativação do quadricípite. Existe também evidência em benefícios a nível circulatório. A maioria dos protocolos utilizam frequências de 50 Hz, sessões 2-3 vezes por semana
com duração media de 30 minutos. Conclusão: Conclui-se que a electroestimulação pode ser uma terapia importante para potenciar a recuperação pós-operatória após artroplastia total do joelho, mas existe ainda pouca evidência e padronização dos protocolos.The present work, in addition to describing and reflecting on the journey of acquiring competencies as a Specialist Nurse in Rehabilitation Nursing, includes an investigative component on a complementary strategy for the rehabilitation of individuals
undergoing total knee arthroplasty. Total knee arthroplasty is a common orthopedic surgery, primarily performed due to osteoarthritis processes. The postoperative period can be challenging, with the Specialist Nurse in Rehabilitation Nursing playing a valuable
role in addressing expected pain, reduced muscle strength, and difficulties in performing daily living activities during the postoperative phase.
Objective: To map the scientific evidence on the effects of electrical stimulation in individuals undergoing total knee arthroplasty.
Methods: A scoping review was conducted following the Joanna Briggs Institute methodology. Searches were performed in PubMed, Scielo, EBSCOhost, and PEDro databases, considering inclusion criteria.
Results: A total of 63 publications were identified, with 9 included in the analysis. NMES (Neuromuscular Electrical Stimulation) was found to have benefits, primarily in activating the quadriceps and reducing pain. Evidence also suggests benefits in circulation. Most protocols used frequencies of 50 Hz, with sessions 2-3 times a week, lasting an average of 30 minutes.
Conclusion: Electrical stimulation may be an important therapy for enhancing postoperative recovery after total knee arthroplasty; however, there is still limited evidence and little standardization of protocols. No studies were found on the use of this complementary therapy by specialist rehabilitation nurses
Avaliação da soldabilidade de aços ao carbono com o processo MAG
Get PDFMestrado de dupla diplomação com a Universidade Tecnológica Federal do ParanáA soldadura MAG é amplamente utilizada devido à sua versatilidade e eficiência na união de aços ao carbono. No entanto, a definição de parâmetros ótimos para o processo ainda é um desafio para garantir a qualidade e a confiabilidade das juntas soldadas. Este estudo teve como objetivo avaliar a soldabilidade do aço carbono no processo MAG, analisando a influência de diferentes parâmetros de soldadura. Para isso, foram realizados ensaios de flexão, tração, dureza Rockwell e análise macrográfica em corpos de prova soldados sob diferentes condições de tensão, velocidade e ângulo de soldadura. A metodologia envolveu um planejamento experimental baseado no método de Taguchi e na análise de variância dos resultados, para determinar a influência de cada parâmetro na qualidade da soldadura, buscando uma combinação ótima. Os resultados mostraram que a escolha adequada dos parâmetros pode otimizar as propriedades mecânicas das juntas soldadas, reduzindo defeitos e melhorando a resistência. Conclui-se que a seleção criteriosa das condições de soldadura é essencial para maximizar a soldabilidade do aço carbono no processo MAG, desempenhando um papel fundamental na obtenção de juntas de alta qualidade.The MAG welding process is widely used because of its versatility and efficiency in joining carbon steels. However, defining the optimal parameters for the process is still a challenge to ensure the quality and reliability of the welded joints. The objective of this study was to evaluate the weldability of carbon steel in the MAG process, analyzing the influence of different welding parameters. Tests of bending, traction, Rockwell hardness and macrographic analysis were conducted on specimens welded under different conditions of welding voltage, speed and angle. The methodology involved experimental planning based on the Taguchi method and analysis of variance of the results, to determine the influence of each parameter on the quality of the weld, in order to find an optimal combination. The results showed that the appropriate selection of parameters can optimize the mechanical properties of welded joints, reducing defects and improving resistance. It is concluded that the careful selection of welding conditions is essential to maximize the weldability of carbon steel in the MAG process, which plays a fundamental role in obtaining high quality joints
Effects of theta-binaural beats auditory stimulation on creativity, psychological well-being and mood states of university students: Pilot study
Get PDFThis study investigates the impact of theta-frequency binaural beats (BB) on creativity, mood, and psychological well-being in university students, addressing the growing interest and controversy surrounding this auditory stimulation technique. A quantitative, correlational, quasi-experimental design was employed, involving 26 university students aged 18–54 (96.2% female, 3.8% male). Participants listened to theta BB (6-Hz beat frequency on a 250 Hz carrier) for 20 minutes daily using the Binaural Beats App. Instruments included a sociodemographic questionnaire, the reduced Creative Personality Scale (EPC), the short Profile of Mood States Questionnaire (POMS), and the Psychological Well-Being Manifestation Scale (EMMBEP). Results revealed significant improvements in creativity, psychological well-being, and reduced total mood disturbance after exposure to theta BB. Significant differences in total mood disturbance across assessment moments highlighted the intervention's time-sensitive benefits. The study highlights the potential of theta-frequency BB to enhance psychological well-being, mood, and creativity among university students. These findings contribute to the growing body of evidence supporting the utility of BB as a non-invasive tool for improving mental and emotional states. Theta BB may serve as an accessible and cost-effective method for promoting mental health and fostering creativity in educational and therapeutic settings.This work is funded by National Funds through the FCT—Foundation for Science and Technology, I.P., by project reference UIDB/05507/2020 and DOI identifier 10.54499/UIDB/05507/2020.
Furthermore, we would like to thank the Center for Studies in Education and Innovation (CI&DEI) and the Polytechnic of Viseu for their support
Exploring cardiovascular risk and plasma ghrelin levels in older adults: a preliminary study
Get PDFCardiovascular diseases are a leading cause of illness and mortality worldwide, with ageing as a key risk factor. As people age, heightened inflammation, oxidative stress, and endothelial dysfunction increase their cardiovascular disease risk. Ghrelin, known as "the hunger hormone," is essential for energy regulation and metabolism. It offers cardiovascular benefits by promoting vasodilation and enhancing endothelial function. With anti-inflammatory and antioxidative properties, ghrelin aids vascular health, making it particularly significant for ageing populations where these processes are often disrupted. Imbalanced ghrelin levels may increase the risk of atherosclerosis and other cardiovascular complications. Understanding these variations in plasma ghrelin levels can offer insights into individual susceptibility to cardiovascular disease and highlight the hormone's role in metabolic and cardiovascular health. This preliminary study aimed to evaluate cardiovascular risk and plasma ghrelin levels in a community of 16 older adults aged 60 or abov
Antimicrobial and wound healing effects associated to cytocompatibility and the relationship with phytochemical profile of selected Portuguese monofloral honeys
Get PDFOwing to its applications in both food and pharmaceutical industries honey is regarded as a functional product. This study evaluated 32 Portuguese monofloral honeys and their activity was compared with manuka honey 850 + .
The antimicrobial activity was determined against Gram-positive and negative bacteria, and yeast. Antioxidant activity, wound healing ability, and cell viability were studied in the human keratinocyte cell line (HaCaT). Phytochemical profile analysis was performed by UPLC/DAD/ESI-MSn. Chestnut, bell heather, eucalyptus, manuka, and strawberry tree honeys demonstrated higher antioxidant activity and were effective against S. aureus. Incense and orange honeys showed wound healing rates of 89 % and 86 %, respectively. All the honeys had cell viability above 76 %. Bell heather and strawberry tree honeys showed the highest total phenolic content, while incense and orange honeys, showed the lower ones. Phytochemical profile analysis evidenced two main clusters, one dominated by isoprenoids and norisoprenoids, as well as phenolic acids and derivatives, while the other included flavonoids as main compounds. Blending different Portuguese monofloral honeys may be an alternative to faster wound healing, by combining their diverse bioactive components. The gathered knowledge can be further explored in formulations that consider the biological activity capacity and composition of each honey.Thanks to Fundação para a Ciência e a Tecnologia (FCT) for the PhD grant SFRH/BD/117013/2016 to Alexandra M. Machado, the grant CEECINST/00145/2018 to Joana Marto, the principal investigator grant
CEECIND/03143/2017 to Lídia Maria Gonçalves, and through the institutional scientific employment program-contract with Soraia I. Falcão. We acknowledge the financial support to FCT/MCTES through
national funds, under CESAM UIDB/50017/2020, DOI 10.54499/UIDB/50017/2020+ UIDP/50017/2020, DOI 10.54499/UIDP/50017/2020+LA/P/0094/2020, DOI 10.54499/LA/P/0094/2020, CIMO, UIDB/00690/2020 (DOI: 10.54499/UIDB/00690/2020) and UIDP/00690/2020 (DOI: 10.54499/UIDP/00690/2020); and SusTEC, LA/P/0007/2020 (DOI: 10.54499/LA/P/0007/2020), MED (https://doi.org/10.54499
UIDB/05183/2020;https://doi.org/10.54499/UIDP/05183/202) and CHANGE (https://doi.org/10.54499/LA/P/0121/2020), UID 04138 - Instituto de Investigação do Medicamento, to FEDER and PT2020 PACompete 2020, project GreenHealth, Norte-01–0145-FEDER-000042 and UID/00329/2025 - Centre for Ecology, Evolution andEnvironmental Changes (CE3C) & CHANGE – Global Change and Sustainability Institute
Ageing at work: impact and consequences – a scoping review
Get PDFAgeism, characterised by
discriminatory aYtudes towards older
individuals based on nega've stereotypes,
is present in various aspects of society,
including workplaces, public spaces, and
healthcare seYngs, influencing the
psychological well-being of the ones
affected. Par'cularly in the workplace,
ageism poses significant challenges for
older workers, affec'ng their produc'vity
and job sa'sfac'on. As the workforce
con'nues to age globally, it’s becoming
increasingly important to address the
consequences of ageism on psychological
health. Methods: A scoping review to map
the evidence concerning the impact of
ageism on the psychological state and wellbeing
of older workers. Following the JBI
methodological recommenda'ons, search
was realized from March to April 2024,
using PubMed, MedLine and CINAHL
databases as well as grey literature to
iden'fy relevant ar'cles. Studies in which
the par'cipants were older adults, focusing
on the influence of aging on psychological
well-being within occupa'onal contexts.
Were included studies published in English,
Spanish and Portuguese developed in the
last 10 years. From 38 cita'ons ini'ally
retrieved, 8 ar'cles met the inclusion
criteria
A Meta-Analysis on the In Vitro Antagonistic Effects of Lactic Acid Bacteria from Dairy Products on Foodborne Pathogens
Get PDFRaw milk and traditional fermented foods such as artisanal cheese represent a natural source of lactic acid bacteria (LAB). They can produce antimicrobial compounds, such as bacteriocins and lactic acid, which may be exploited in dairy biopreservation. This study aimed to conduct a systematic review and meta-analysis to synthesize the inhibition diameter (ID) of LAB against L. monocytogenes, S. aureus, and Salmonella spp. Literature electronic searches were performed on PubMed, Scopus, and Web of Science, to identify articles that reported data on in-vitro antimicrobial activity by LAB isolated from dairy foods. A total of 1665 papers were retrieved, and 20 primary studies were selected according to the selection criteria, of which 397 observations were extracted. Random-effects meta-regression models were employed to describe the effects of LAB genus, pathogen concentration, susceptibility method, incubation time, inoculation volume, agar type and pH on the IDs for L. monocytogens, S. aureus, and Salmonella spp. L. monocytogens was the most susceptible pathogen (p < 0.05) to the LAB effects, followed by S. aureus and Salmonella spp. As a whole, LAB from the Lacticaseibacillus genus were the most effective (p < 0.05) in inhibiting L. monocytogens (21.49 ± 2.654 mm), followed by S. aureus (21.06 ± 2.056 mm). Salmonella spp. presented higher (p < 0.05) susceptibility to Lactobacillus genus (19.93 ± 2.456 mm). From the results, a general trend could be observed for the well-diffusion method to produce higher (p < 0.05) ID estimates than the spot and disk methods (30.73 ± 2.530 mm vs. 21.98 ± 1.309 mm vs. 13.39 ± 1.403 mm for L. monocytogenes; 22.37 ± 1.073 mm vs. 14.91 ± 2.312 mm vs. 20.30 ± 2.319 mm for Salmonella spp.), respectively. Among the tested moderators, the pathogen’s inoculum concentration, the in vitro susceptibility assay itself, incubation time and inoculation volume on agar are determinant parameters to be looked at when designing a robust and reproducible experimental plan. The in vitro results reinforced that LAB can be useful in controlling the development of pathogenic bacteria frequently found in the dairy industry.This research was funded by the Foundation for Science and Technology (FCT, Portugal) through national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2021) and through funding of the PAS-AGRO-PAS project (PRIMA/0014/2022). Y. Loforte acknowledges the financial support provided by FCT through the Ph.D. grant PRT/BD/152089/2021. A. M. Almeida acknowledges funding by national funds through FCT—Fundação para a Ciência e a Tecnologia, I.P., under the projects UIDB/04129/2020 of LEAF-Linking Landscape, Environment, Agriculture and Food, Research Unit and LA/P/0092/2020 of Associate Laboratory TERRA