Browsing by Issue Date, starting with "2024-06-20"
Now showing 1 - 7 of 7
Results Per Page
Sort Options
- Development and implementation of a smart charging system for electric vehicles based on the ISO 15118 standardPublication . Santos, Joni; Francisco, André; Cabrita, Cristiano Lourenço; Monteiro, Jânio; Pacheco, André; Cardoso, PedroThere is currently exponential growth in the electric vehicle market, which will require an increase in the electrical grid capacity to meet the associated charging demand. If, on the one hand, the introduction of energy generation from renewable energy sources can be used to meet that requirement, the intermittent nature of some of these sources will challenge the mandatory real-time equilibrium between generation and consumption. In order to use most of the energy generated via these sources, mechanisms are required to manage the charging of batteries in electric vehicles, according to the levels of generation. An effective smart charging process requires communication and/or control mechanisms between the supply equipment and the electric vehicle, enabling the adjustment of the energy transfer according to the generation levels. At this level, the ISO 15118 standard supports high-level communication mechanisms, far beyond the basic control solutions offered through the IEC 61851-1 specification. It is, thus, relevant to evaluate it in smart charging scenarios. In this context, this paper presents the development of a charge emulation system using the ISO 15118 communication protocol, and it discusses its application for demand response purposes. The system comprises several modules developed at both ends, supply equipment and electric vehicles, and allows the exchange of data during an emulated charging process. The system also includes human interfaces to facilitate interactions with users at both ends. Tests performed using the implemented system have shown that it supports a demand response when integrated with a photovoltaic renewable energy source. The dynamic adjustment to charging parameters, based on real-time energy availability, ensures efficient and sustainable charging processes, reducing the reliance on the grid and promoting the use of renewable energy.
- Exploiting graph neural network with one-shot learning for fault diagnosis of rotating machineryPublication . Shuai Yang; Xu Chen; Yu Wang; Yun Bai; Pu, ZiqiangInsufficient training data often leads to overfitting, posing a significant challenge in diagnosing faults in mechanical devices, particularly rotating machinery. To address this issue, this paper introduces a novel approach employing a graph neural network (GNN) with one-shot learning for fault diagnosis in rotating machinery. Firstly, the Short-Time Fourier Transform (STFT) is utilized for data preprocessing to convert the one-dimensional data into two-dimensional pictures. Subsequently, Feature extraction a convolutional neural network (CNN) is utilized to perform feature extraction. By introducing the adjacency matrix to explore the spatial information within data, a graph neural network (GNN) method is proposed to achieve the fault classification of rotating machinery with small sample. The method utilizes GNN to process structural information between, transferring the distance metric from Euclidean space to non-Euclidean space. Classification accuracy is thereby improved based on information processing in non-Euclidean space.Experiments were implemented on two datasets to verify the proposed method, including an open dataset of the rolling bearing and an experimental rig of the rotate vector (RV) reducer in an industrial robot. Siamese Net, Matching Net, and sparse auto-encoder with random forest (SAE + RF) wereemployed as the comparisons to further prove the effectiveness of the proposed method. Results indicate that the proposed method outperforms all the comparative methods in both rotating machineries.
- Experiences with emergency distance education: a dilemma between face-to-face education and distance education in tour guidingPublication . ALTINAY ÖZDEMİR, MELTEM; Tombaş, ZeynepUniversities switched from face-to-face to emergency distance education as a solution to the crisis during the Covid-19 pandemic. This enabled face-to-face students to experience distance education. This study examined these experiences for tour guiding education. Distance education was available in tour guiding departments at a few T & uuml;rkiye universities before the pandemic, and this was a discussion topic in academic. However, emergency distance education presented a dilemma for students: distance education or face-to-face education. Thus, the research includes students in the face-to-face tour guiding departments. A qualitative, phenomenological approach was employed to collect data using semi-structured interviews and an online questionnaire. Data were analyzed using thematic content analysis. The findings revealed that students preferred face-toface education while being uncertain about the pros and cons of distance education. However, this decision should be underlined as not definitive. The study emphasizes that distance education is ineffective for tour guiding education due to the absence of practical courses, which are crucial for tour guiding, as well as effective communication. The study provides theoretical insights into the educational strategies used in tourism during crises and offers practical implications for enhancing distance education in higher education institutions.
- Sediment DNA can revolutionize archaeology—if it is used the right wayPublication . aldeias, vera; Stahlschmidt, Mareike C.The possibility of fingerprinting ancient organisms using the DNA they leave behind is a revolution in our understanding of the past. Paleogenetic studies are rewriting our knowledge on ancient hominin genomes, hominin dispersals, interbreeding events, and ancient DNA is also a key tool in biodiversity monitoring efforts. Of particular interest: We can now retrieve DNA directly from sediments and soils (sedaDNA) (1–3) in a variety of modern and past depositional environments, including permafrost, lakes, marine sediments, or caves settings.
- Mapeamento e mitigação de riscos ocupacionais na indústria corticeira: um estudo de caso em ambiente fabrilPublication . Silva, Mário Jorge Castela da; Sousa, AntónioNum mundo em constante transformação, caracterizado pelo incremento da procura de bens e pela necessidade de adotar práticas de produção sustentáveis, emerge a indústria 4.0 [I4.0] definida pela automação e digitalização dos processos. Como evolução natural, Coelho et al. (2022) introduzem o conceito de Indústria 5.0 [I5.0], marcando a transição para uma nova fase que enfatiza a centralidade do ser humano na inovação industrial, refletindo as aspirações da União Europeia [EU] para o futuro da indústria. Este cenário apresenta desafios significativos na área da segurança e saúde no trabalho [SST], exigindo novas abordagens. O presente estudo de caso aclara como a Corticeira Amorim enfrenta esses desafios, através de uma parceria estratégica com a UAlg, reconhecida pela sua competência científica e técnica e pelo seu compromisso com o desenvolvimento social. Realizado numa unidade industrial em Silves, distrito de Faro, o estudo focou-se na identificação, avaliação e mitigação dos riscos inerentes ao processo produtivo. A investigação iniciou pela análise das metodologias de gestão dos riscos de SST existentes. Concluiu-se pela inadequação dos métodos qualitativos para os objetivos propostos, dada a sua limitação em abordar a complexidade dos riscos adequadamente. Similarmente, os métodos quantitativos foram preteridos devido à sua complexidade, custos e limitações temporais. Assim, adotou-se a Metodologia de Avaliação de Riscos e Acidentes de Trabalho [M.A.R.A.T.], um método simplificado já incorporado nas práticas da empresa com outra designação. O estudo adotou uma abordagem semiquantitativa e transversal, incluindo uma amostra de 31 colaboradores. As conclusões destacam a crescente complexidade nos ambientes industriais e a urgência de implementar estratégias concentradas nas áreas críticas. É fundamental a aceitação e adesão dos trabalhadores às novas práticas, face aos desafios e oportunidades que emergem da interação entre homem e máquina, enfatizando a importância de as organizações adotarem uma postura proativa.
- Pharmacological and behavioral investigation of putative self-medicative plants in budongo chimpanzee dietsPublication . Freymann, Elodie; Carvalho, Susana; Garbe, Leif A.; Ghazhelia, Dinda Dwi; Hobaiter, Catherine; Huffman, Michael A.; Muhumuza, Geresomu; Schulz, Lena; Sempebwa, Daniel; Wald, Florian; Yikii, Eguma R.; Zuberbühler, Klaus; Schultz, Fabien; Armel Jackson SeukepWild chimpanzees consume a variety of plants to meet their dietary needs and maintain wellbeing. While some plants have obvious value, others are nutritionally poor and/or contain bioactive toxins which make ingestion costly. In some cases, these nutrient-poor resources are speculated to be medicinal, thought to help individuals combat illness. In this study, we observed two habituated chimpanzee communities living in the Budongo Forest, Uganda, and collected 17 botanical samples associated with putative self-medication behaviors (e.g., bark feeding, dead wood eating, and pith-stripping) or events (e.g., when consumer had elevated parasite load, abnormal urinalysis, or injury). In total, we selected plant parts from 13 species (nine trees and four herbaceous plants). Three extracts of different polarities were produced from each sample using n-hexane, ethyl acetate, and methanol/water (9/1, v/v) and introduced to antibacterial and anti-inflammatory in vitro models. Extracts were evaluated for growth inhibition against a panel of multidrug-resistant clinical isolates of bacteria, including ESKAPE strains and cyclooxygenase-2 (COX-2) inhibition activity. Pharmacological results suggest that Budongo chimpanzees consume several species with potent medicinal properties. In the antibacterial library screen, 45 out of 53 extracts (88%) exhibited ≥40% inhibition at a concentration of 256 μg/mL. Of these active extracts, 41 (91%) showed activity at ≤256μg/mL in subsequent dose-response antibacterial experiments. The strongest antibacterial activity was achieved by the n-hexane extract of Alstonia boonei dead wood against Staphylococcus aureus (IC50: 16 μg/mL; MIC: 32 μg/mL) and Enterococcus faecium (IC50: 16 μg/mL; MIC: >256 μg/mL) and by the methanol-water extract of Khaya anthotheca bark and resin against E. faecium (IC50: 16 μg/mL; MIC: 32 μg/mL) and pathogenic Escherichia coli (IC50: 16 μg/mL; MIC: 256 μg/mL). We observed ingestion of both these species by highly parasitized individuals. K. anthotheca bark and resin were also targeted by individuals with indicators of infection and injuries. All plant species negatively affected growth of E. coli. In the anti-inflammatory COX-2 inhibition library screen, 17 out of 51 tested extracts (33%) showed ≥50% COX-2 inhibition at a concentration of 5 μg/mL. Several extracts also exhibited anti-inflammatory effects in COX-2 dose-response experiments.
- Tratamento de tumores com recurso a radiações. Uso de complexos com radionuclídeosPublication . NASCIMENTO, MARTA ISABEL SANTOS; Lourenço, João Paulo Gil LourençoO cancro é atualmente considerado a segunda maior causa de morte em Portugal. Caracteriza-se por um crescimento celular desregulado, levando à formação de tumores, que por sua vez, podem invadir outros tecidos e órgãos próximos por infiltração ou até proliferar para outras zonas do corpo através de metástases. Devido à grande diversidade de mecanismos de crescimento e diversas respostas de cada doente às diferentes terapias existentes, o tratamento do cancro continua a ser um grande desafio nos dias de hoje. A grande preocupação na comunidade científica passa por encontrar o equilíbrio certo entre o controle do tumor e a lesão de tecidos normais, tendo em conta que todas as terapêuticas atualmente existentes afetam também em grande parte os tecidos saudáveis do corpo, dando origem a graves efeitos indesejáveis. Diversos radionuclídeos metálicos têm mostrado um elevado potencial nesta área da medicina, quer em diagnóstico, quer em terapêutica ou ainda combinando as duas funções. Estes radionuclídeos, normalmente na forma de iões metálicos, se combinados com ligandos adequados, permitem que a radiação emitida, tais como radiação gama resultante da emissão de positrões ou decaimento radioativo, ou radiação beta, que ocorre junto, ou no próprio tecido afetado, leve a melhores resultados quer em termos de imagiologia quer em termos de terapêutica. A química de coordenação surge assim como um fator-chave no desenvolvimento de novos fármacos, bem como na compreensão do seu comportamento in vivo. Ao longo desta monografia é avaliado o potencial da terapêutica com radiofármacos seletivos, bem como o seu uso em imagiologia, sendo abordados exemplos de diversos complexos que ilustram as suas diferentes características e potencialidades.