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Publicações

2024

The GRAVITY young stellar object survey: XII. The hot gas disk component in Herbig Ae/Be stars

Autores
Lopez, RG; Natta, A; Fedriani, R; Garatti, ACO; Sanchez-Bermudez, J; Perraut, K; Dougados, C; Bouarour, YI; Bouvier, J; Brandner, W; Garcia, P; Koutoulaki, M; Labadie, L; Linz, H; Alécian, E; Benisty, M; Berger, JP; Bourdarot, G; Caselli, P; Clénet, Y; de Zeeuw, PT; Davies, R; Eckart, A; Eisenhauer, F; Förster-Schreiber, NM; Gendron, E; Gillessen, S; Grant, S; Henning, T; Kervella, P; Lacour, S; Lapeyrère, V; Le Bouquin, JB; Lutz, D; Mang, F; Nowacki, H; Ott, T; Paumard, T; Perrin, G; Shangguan, J; Shimizu, T; Soulain, A; Straubmeier, C; Sturm, E; Tacconi, L; van Dishoeck, EF; Vincent, F; Widmann, F;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
Context. The region of protoplanetary disks closest to a star (within 1-2 au) is shaped by a number of different processes, from accretion of the disk material onto the central star to ejection in the form of winds and jets. Optical and near-IR emission lines are potentially good tracers of inner disk processes if very high spatial and/or spectral resolution are achieved. Aims. In this paper, we exploit the capabilities of the VLTI-GRAVITY near-IR interferometer to determine the location and kinematics of the hydrogen emission line Br gamma. Methods. We present VLTI-GRAVITY observations of the Br gamma line for a sample of 26 stars of intermediate mass (HAEBE), the largest sample so far analysed with near-IR interferometry. Results. The Br gamma line was detected in 17 objects. The emission is very compact (in most cases only marginally resolved), with a size of 10-30 R*(1-5 mas). About half of the total flux comes from even smaller regions, which are unresolved in our data. For eight objects, it was possible to determine the position angle (PA) of the line-emitting region, which is generally in agreement with that of the inner-dusty disk emitting the K-band continuum. The position-velocity pattern of the Br gamma line-emitting region of the sampled objects is roughly consistent with Keplerian rotation. The exception is HD 45677, which shows more extended emission and more complex kinematics. The most likely scenario for the Br gamma origin is that the emission comes from an MHD wind launched very close to the central star, in a region well within the dust sublimation radius. An origin in the bound gas layer at the disk surface cannot be ruled out, while accreting matter provides only a minor fraction of the total flux. Conclusions. These results show the potential of near-IR spectro-interferometry to study line emission in young stellar objects.

2024

Developing Entrepreneurial Competencies among Tourism Students using FLIGBY

Autores
Ferro, A; Buzady, Z; Almeida, F;

Publicação
JOURNAL OF HOSPITALITY & TOURISM EDUCATION

Abstract
This article seeks to present an initiative to integrate a serious game into an entrepreneurship course, attended by tourism students, which enables them to have a more reliable and comprehensive experience of the multiple dimensions of this phenomenon. The study uses a mixed-methods approach to explore several dimensions of the impact on the use of the game by measuring student performance and conducting semi-structured interviews. The findings indicate that FLIGBY has helped the tourism students to have a more complete and reliable perception of the business reality and to practice their skills in a wide range of areas such as emotional intelligence, conflict management, time management, strategic thinking, or leadership. The results also indicate the development of analytical skills in the area of business management and viniculture due to the central theme of FLIGBY.

2024

Proceedings of the 19th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications, VISIGRAPP 2024, Volume 2: VISAPP, Rome, Italy, February 27-29, 2024

Autores
Radeva, P; Furnari, A; Bouatouch, K; de Sousa, AA;

Publicação
VISIGRAPP (2): VISAPP

Abstract

2024

A Multi-User Multi-Robot Collaboration through Augmented Reality

Autores
Martins, JG; Costa, GM; Petry, MR; Costa, P; Moreira, AP;

Publicação
2024 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS, ICARSC

Abstract
Current industrial environments have multiple robots working alongside humans, thus providing an operator the ability to perceive the robot's workspace correctly and to anticipate its intentions and movements through the visualization of the robot's digital twin is of utmost importance for safe and productive human-robot collaboration scenarios. Much has been studied regarding single human-single robot collaborative scenarios, but few address multi-user multi-robot scenarios. To this end, this paper presents a multi-robot multi-operator architecture, where the users' awareness is enhanced through an augmented reality head-mounted display. A multi-robot, multi-user collaborative scenario is presented in a laboratory environment with two industrial robots. Besides being able to interact with both robots in the system, each user becomes more aware of the robot's workspace and its pre-defined trajectories. Furthermore, it presents how fiducial markers can help to establish the relation between the different coordinate frames.

2024

Enhancing Smart Manufacturing Systems: A Digital Twin Approach Employing Simulation, Flexible Robots and Additive Manufacturing Technologies

Autores
Santos, R; Rocha, C; Dias, R; Quintas, J;

Publicação
SIMULATION FOR A SUSTAINABLE FUTURE, PT 1, EUROSIM 2023

Abstract
A new generation of manufacturing systems is emerging through the adoption of new policies to overcome future crises highlighted by constant social, environmental, and economic concerns. The rise of so-called smart manufacturing is noticeable. However, new risks to humankind are being introduced, and, more than ever, science and technology are required to guarantee the future sustainability and resilience of our manufacturing systems. This research presents a Digital Twin approach resorting to simulation models with embedded intelligence to transform efficient manufacturing systems and react to complex and unpredictable circumstances. The methodology covers production scheduling incorporating flexible robots, internal logistics supervision contemplating planning and control of mobile robots, and capacity management. The method demonstrates the potential of integrating Additive Manufacturing technologies to quickly react to production needs. The developed strategy was enforced and assessed in an industrial experiment, exhibiting its robustness and promising application. The attained results were very encouraging, highlighting its potential extension to more complex industrial systems.

2024

Material design-for-X: A decision-making tool applied for high-performance applications

Autores
Oliveira, BF; Pinto, SM; Costa, C; Castro, J; Gouveia, JR; Matos, JR; Dutra, TA; Baptista, AJ;

Publicação
MATERIALS TODAY COMMUNICATIONS

Abstract
As the need for enhanced material performance continues to escalate in several sectors, addressing complex parameters such as economic feasibility, ease of manufacturing, and production volume, rises the need for multidomain decision-making tools. In order to explore and streamline this process, this study employed the novel Material Design-for-eXcellence methodology to investigate polymer material selection in aeronautical and power transformer components, using additive manufacturing. The study assessed the X's selected (mechanical, thermal, physical, cost, dielectric, and environmental) by assigning weights to these factors, and identifying the optimal materials for each application. In the aeronautical context, PEI+GF30 was chosen as the best solution, attaining an overall effectiveness of 79 %, primarily due to its exceptional mechanical characteristics. The use of a thermoplastic can lead to lighter components while ensuring the same technical performance, enabling longer flight duration. Conversely, in the energy sector for power transformers, PSU obtained a 78 % score, largely attributable to its outstanding dielectric properties. The application of additive methods on transformers' insulating parts leads to optimized channels for the mineral oil, enhancing its thermal and dielectric performance. The obtained results underscored the importance of tailored material selection approaches, adjusted to specific application requirements. The importance of comprehending and adapting to diverse contexts for effective material design and implementation is also highlighted.

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