2025
Autores
da Silva, PM; Mendes, JP; Martins, F; Silva, AMG; de Almeida, JMMM; Coelho, LCC;
Publicação
SENSORS AND ACTUATORS A-PHYSICAL
Abstract
Carbon dioxide (CO2) plays a crucial role in the biosphere, acting as an indicator of anthropogenic activity. Its monitoring is fundamental for controlling air and water quality, preserving the environment and optimizing industrial processes. The preparation of a bright fluorescent scaffold, named rhodol, was optimized by employing microwave heating as an alternative heating source, achieving shorter reaction times and higher yields. Structural characterization was performed by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS-ESI). Its application to produce a fluorescent optical membrane for monitoring CO2 in gas (gCO2) and in water (dCO2) was explored. Two different setups are used for this purpose, and in both, the same optical response is observed: the membrane's fluorescence intensity decreases as the CO2 concentration increases. The sensor's reliability for dCO2 is demonstrated through testing concentrations ranging from 1 ppm to 100 ppm with minimal photobleaching (0.0026 dB) over 7500 data points with an integration time of 200 ms each. The sensor performance for dCO2 evaluation exhibits an experimental error of +/- 1.81 ppm, a response time of 2 min, a limit of detection of 0.6 ppm and a Stokes-shift of 90 nm for concentrations between 1 and 100 ppm. Monitoring of gCO2 using this membrane is hindered by changes in relative humidity (RH), hence the results for concentration between 0.3 % and 100 % of gCO2 were achieved by maintaining a consistent high value of RH. Our findings highlight the effectiveness of the optimized rhodol synthesis and its application in an optical membrane for reliable monitoring of CO2 in various environmental conditions.
2025
Autores
Sousa, N; Alén, E; Losada, N; Melo, M;
Publicação
TOURISM & MANAGEMENT STUDIES
Abstract
Virtual Reality (VR) has been recognised as a promising technology for enhancing the tourist experience. However, little is known about the intention of tourism business managers to adopt VR for leisure purposes. In this context, this study aims to explore this intention by interviewing managers in the sector. This process allowed us to examine their perceptions regarding the use of this technology in their business models. The results revealed that the perceived usefulness of VR is a key factor in its adoption. In addition, managers recognise the value of VR as a complement to the tourist visit, and their intention to adopt it increases when a positive return on investment is anticipated. This approach offers a unique perspective on the main factors influencing technology adoption in this context, broadens the understanding of VR applications in wine tourism, and highlights its potential to transform the visitor experience and drive growth in the sector through innovative business models.
2025
Autores
Chandramohan, MS; da Silva, IM; Ribeiro, RP; Jorge, A; da Silva, JE;
Publicação
ENVIRONMENTS
Abstract
This study investigates spatial distribution and chemical elemental composition screening in soils in Rome (Italy) using X-ray fluorescence analysis. Fifty-nine soil samples were collected from various locations within the urban areas of the Rome municipality and were analyzed for 19 elements. Multivariate statistical techniques, including nonlinear mapping, principal component analysis, and hierarchical cluster analysis, were employed to identify clusters of similar soil samples and their spatial distribution and to try to obtain environmental quality information. The soil sample clusters result from natural geological processes and anthropogenic activities on soil contamination patterns. Spatial clustering using the k-means algorithm further identified six distinct clusters, each with specific geographical distributions and elemental characteristics. Hence, the findings underscore the importance of targeted soil assessments to ensure the sustainable use of land resources in urban areas.
2025
Autores
Silva, CAM; Bessa, RJ;
Publicação
APPLIED ENERGY
Abstract
The electrification of the transport sector is a critical element in the transition to a low-emissions economy, driven by the widespread adoption of electric vehicles (EV) and the integration of renewable energy sources (RES). However, managing the increasing demand for EV charging infrastructure while meeting carbon emission reduction targets is a significant challenge for charging station operators. This work introduces a novel carbon-aware dynamic pricing framework for EV charging, formulated as a chance-constrained optimization problem to consider forecast uncertainties in RES generation, load, and grid carbon intensity. The model generates day-ahead dynamic tariffs for EV drivers with a certain elastic behavior while optimizing costs and complying with a carbon emissions budget. Different types of budgets for Scope 2 emissions (indirect emissions of purchased electricity consumed by a company) are conceptualized and demonstrate the advantages of a stochastic approach over deterministic models in managing emissions under forecast uncertainty, improving the reduction rate of emissions per feasible day of optimization by 24 %. Additionally, a surrogate machine learning model is proposed to approximate the outcomes of stochastic optimization, enabling the application of state-of-the-art explainability techniques to enhance understanding and communication of dynamic pricing decisions under forecast uncertainty. It was found that lower tariffs are explained, for instance, by periods of higher renewable energy availability and lower market prices and that the most important feature was the hour of the day.
2025
Autores
Matos, DM; Costa, P; Sobreira, H; Valente, A; Lima, J;
Publicação
INTERNATIONAL JOURNAL OF INTELLIGENT ROBOTICS AND APPLICATIONS
Abstract
With the increasing adoption of mobile robots for transporting components across several locations in industries, congestion problems appear if the movement of these robots is not correctly planned. This paper introduces a fleet management system where a central agent coordinates, plans, and supervises the fleet, mitigating the risk of deadlocks and addressing issues related to delays, deviations between the planned paths and reality, and delays in communication. The system uses the TEA* graph-based path planning algorithm to plan the paths of each agent. In conjunction with the TEA* algorithm, the concepts of supervision and graph-based environment representation are introduced. The system is based on ROS framework and allows each robot to maintain its autonomy, particularly in control and localization, while aligning its path with the plan from the central agent. The effectiveness of the proposed fleet manager is demonstrated in a real scenario where robots operate on a shop floor, showing its successful implementation.
2025
Autores
Pedroso, DF; Almeida, L; Pulcinelli, LEG; Aisawa, WAA; Dutra, I; Bruschi, SM;
Publicação
IEEE ACCESS
Abstract
Cloud computing technologies offer significant advantages in scalability and performance, enabling rapid deployment of applications. The adoption of microservices-oriented architectures has introduced an ecosystem characterized by an increased number of applications, frameworks, abstraction layers, orchestrators, and hypervisors, all operating within distributed systems. This complexity results in the generation of vast quantities of logs from diverse sources, making the analysis of these events an inherently challenging task, particularly in the absence of automation. To address this issue, Machine Learning techniques leveraging Large Language Models (LLMs) offer a promising approach for dynamically identifying patterns within these events. In this study, we propose a novel anomaly detection framework utilizing a microservices architecture deployed on Kubernetes and Istio, enhanced by an LLM model. The model was trained on various error scenarios, with Chaos Mesh employed as an error injection tool to simulate faults of different natures, and Locust used as a load generator to create workload stress conditions. After an anomaly is detected by the LLM model, we employ a dynamic Bayesian network to provide probabilistic inferences about the incident, proving the relationships between components and assessing the degree of impact among them. Additionally, a ChatBot powered by the same LLM model allows users to interact with the AI, ask questions about the detected incident, and gain deeper insights. The experimental results demonstrated the model's effectiveness, reliably identifying all error events across various test scenarios. While it successfully avoided missing any anomalies, it did produce some false positives, which remain within acceptable limits.
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