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563 results on '"Carvalho, O"'

52. Multi-material laser powder bed fusion of embedded thermocouples in WC-Co cutting tools

Author

Guimarães, B., Fernandes, C.M., Figueiredo, D., Carvalho, O., Miranda, G., and Silva, F.S.

Abstract

During machining processes, due to deformation of the material and friction of the chip along the tool surface, a significant amount of heat is generated, particularly in the cutting zone, thus leading to a wear increase and consequent tool life reduction. Therefore, the ability to assess the cutting temperature in real time is extremely important to better understand heat generation, thus contributing to the development of more effective strategies for reducing machining costs and increasing tool life and productivity.

Published
2024
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53. Role of oxide support in electrocatalytic nitrate reduction on Cu.

Author

Carvalho, O. Quinn, Jones, Sophia R. S., Berninghaus, Ashley E., Hilliard, Richard F., Radniecki, Tyler S., and Stoerzinger, Kelsey A.

Subjects
*DENITRIFICATION, *COPPER, *ELECTROLYTIC reduction, *CERIUM oxides, *STANNIC oxide, *CATALYST supports, *CHEMICAL synthesis, *METALLIC oxides
Abstract

The electrochemical nitrate reduction reaction (NO3RR) has the potential for distributed water treatment and renewable chemical synthesis. Cu is an active monometallic electrocatalyst for the NO3RR in acidic and alkaline electrolytes, where activity is limited by the reduction of adsorbed nitrate to nitrite. Oxygen‐vacancy forming metal‐oxide supports provide sites for N‐O bond activation in thermal reduction, impacting product distribution as well. Here we compare the electrochemical NO3RR activity of Cu deposited on two metal‐oxide supports (cerium dioxide [Cu/CeO2‐δ] and fluorine‐doped tin dioxide [Cu/FTO]) to a Cu foil benchmark. Considering activity in phosphate‐buffered neutral media, nitrate and adsorbed hydrogen compete for surface sites under NO3RR conditions. The less‐cathodic overpotential on Cu/CeO2‐δ compared to Cu/FTO is attributed to stronger nitrate adsorption, similar to thermal nitrate reduction. Utilization of CeO2‐δ as an electrocatalyst support slightly shifting product distribution toward more oxidized products, either by enhancing nitrate affinity or by a more dynamic process involving the formation and healing of oxygen vacancies (푣O••). These results suggest supporting catalysts on metal oxides may enhance activity by promoting the adsorption of anionic reactants on cathodic electrocatalysts. [ABSTRACT FROM AUTHOR]

Published
2024
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59. Mito e o Ensino de História e Cultura Indígena em perspectiva decolonial

Author

Renata Carvalho o Silva

Subjects
Populações indígenas, Mitologia, History (General), D1-2009, Latin America. Spanish America, F1201-3799, Colonies and colonization. Emigration and immigration. International migration, JV1-9480
Abstract

O texto a seguir tem como proposta analisar como as narrativas mitológicas ameríndias podem auxiliar no ensino de História e Cultura Indígena em sala de aula buscando perceber de que forma as mudanças de perspectiva nas representações acerca das identidades étnicas na América Latina, bem como a oposição entre os pressupostos epistemológicos eurocentrados e as emergências pluriétnicas nos contextos póscoloniais visam empreender uma crítica aos modelos paradigmáticos modernos para uma educação com foco na interculturalidade. Palavras-chave: História indígena, mitologias, ensino.

Published
2018
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65. 3D Multi-Material Laser Powder Bed Fusion: a disruptive approach to design/manufacture unparalleled multi-functional solutions

Author

Bartolomeu, Flávio, Carvalho, O., Pires, J., Cunha, A., Marques, A., Gasik, M., Silva, Filipe Samuel, and Universidade do Minho

Subjects
Educação de qualidade, Engenharia e Tecnologia::Engenharia Mecânica
Abstract

[Excerpt] Engineering has been so far a mono-dimension tool where components are mono-material, dense unoptimized and designed for one or two requirements, due to processes’ limitations. Traditional components diverge entirely from lightweight and multi-material nature structures endowed with a high level of multi-functionality. [...], This work was supported by FCT national funds, under the national support to R&D units grant, through the reference projects UIDB/04436/2020 and UIDP/04436/2020.

Published
2022

73. 3D Multi-Material-Selective-Laser-Melting: technology, fabrication and prototypes

Author

Bartolomeu, Flávio, Pires, J., Marques, A., Cunha, A., Carvalho, O., Gasik, M., Silva, F. S., and Universidade do Minho

Abstract

[Excerpt] Contrarily to nature, human traditional strategies and inventions both from process and products point of view, use brute force, heavy and inefficient, single and inanimate material (like brick, steel and glass) solutions with unoptimized architectures [1] . To create and developed superior engineering solutions, advanced manufacturing technologies are necessary to evolve from mono-material to multi-material components, from mono-scale to multi-scale added parts, from limited geometries to almost any geometry. Recent man-made use additive technologies and in particular powder-based technologies which possess some principles, similar to nature, where the component is grown, step by step, sequentially. A suitable and high-advanced manufacturing and engineering strategy is necessary for combining dissimilar materials in the same part and thus, combine different and advantageous properties not possible to obtain using single material’s solutions. [...], This work was supported by FCT national funds, under the national support to R&D units grant, through the reference projects UIDB/04436/2020 and UIDP/04436/2020

Published
2022

78. LBA-5 Phase Ib study of the anti-TIGIT antibody tiragolumab in combination with atezolizumab in patients with metastatic esophageal cancer

Author

Wainberg, Z., primary, Matos, I., additional, Delord, J., additional, Cassier, P., additional, Gil-Martin, M., additional, Kim, T., additional, LoRusso, P., additional, Bahleda, R., additional, Italiano, A., additional, Mendus, D., additional, Hoang, T., additional, Xue, C., additional, Wen, X., additional, Carvalho, O., additional, Pham, T., additional, Patil, N., additional, Meng, R., additional, Bendell, J., additional, Cervantes, A., additional, and Cho, B., additional

Published
2021
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79. A Novel Approach for Micro-Antenna Fabrication on ZrO 2 Substrate Assisted by Laser Printing for Smart Implants.

Author

Moura, C. G., Dinis, H., Carvalho, O., Mendes, P. M., Nascimento, R. M., and Silva, F. S.

Subjects
LASER printing, ANTENNA design, TITANIUM alloys, MICROCAVITY lasers, TELECOMMUNICATION systems, METAL ions, RUTHERFORD backscattering spectrometry
Abstract

The use of Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) in medicine has rapidly expanded over the past decade, driven by its advantageous properties, showing potential to overcome titanium alloy in implant fabrication. The release of metal ions and the aesthetic problems of titanium alloy implants are the main reasons for this trend. In addition to meeting expectations regarding its properties, an implant must possess intrinsic capacities such as auto-diagnostic and auto-treatment. Thus, based on the concept of smart implants, this work proposes a hybrid approach for printing a part of the communication system of a zirconia implant by resorting to laser technology, aiming to endow the implant with intrinsic capacities. Therefore, the antenna was designed and then printed on the zirconia surface. The laser was applied as a versatile tool, whether for preparing the surface of the material in a subtractive way, by creating the micro-cavity, or for printing the silver-based antenna in an additive way through laser technology. The silver powder was used as the conductor material of the antenna. The results revealed that the antenna is capable of communicating from inside the body with the outside world without needing to have an exterior antenna attached to the skin. [ABSTRACT FROM AUTHOR]

Published
2022
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88. SUSTAINABILITY FACTORS IN INTERNATIONAL PROJECT TEAMS

Author

Rua Saraiva de Carvalho, – º Dto, Lisbon, Portugal, Cice, Leonilde Reis, Ips, Campus do Ips, Estefanilha Setúbal, Portugal, Renato Duarte, Estg, Ipg, Avenida Dr. Francisco Sá Carneiro, nº , Gab. , Portugal, Clara Silveira, Udi, and Esce

Subjects
Sustainability, Business, Environmental planning
Abstract

Today almost all organizations, according with their business specificities, support their business activity within the Information Systems. In this sense, the most common business processes of organizations are supported by generic software products, also called Enterprise Resource Planning. In this paper are referred a set of good practices for the implementation/configuration of generic software products, in international projects. The methodology adopted focuses on the literature review in the thematic of Sustainability factors in International Project Teams, as well as on the presentation of good practices based on the lessons learnt from proven methodology. The contributions of this work focus on considerations in the area of project implementation procedures, and requirements of the business processes, the system configuration, as well as training. The paper’s conclusions emphasize the importance of applying good support management in international project teams, including concerns of sustainable development objectives in the economic, technical, social, human/individual and environmental aspects.

Published
2020
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90. Pure magnesium laser surface modification using Nd:YAG laser.

Author

Pereira, H., Carvalho, O., Miranda, G., and Silva, F. S.

Subjects
*ND-YAG lasers, *MAGNESIUM, *NEODYMIUM lasers, *LASERS, *CORROSION in alloys, *SCANNING electron microscopy, *SURFACE texture, *IMAGE analysis
Abstract

Magnesium (Mg) and its alloys are promising materials for a wide range of biomedical applications due to its biodegradability. Nevertheless, their rapid corrosion dictates the need to develop strategies to control these materials' corrosion rate. In fact, several surface modification techniques have been used to retard the corrosion of Mg and its alloys. Laser technology can be used to tailor Mg surfaces aiming to modify exposed area/roughness and thus control the biocorrosion process. This work presents a detailed study on pure Mg surface texturing by an Nd:YAG laser and their morphological characterisation, aiming to create either localised texturing or remelted areas. The characterisation of the textured and remelted surfaces was carried out by scanning electron microscopy and analysed using image analysis software (Image J) for obtaining their depth and width. Results show that higher scan speed (400 mm/s) and lower laser power (1.5 W) were unsuitable for machining pure Mg. The parameters to perform texturing and remelting are discussed herein. [ABSTRACT FROM AUTHOR]

Published
2021
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92. Current investigations on tritiated dust and its impact on tokamak safety

Author

Grisolia, C., primary, Gensdarmes, F., additional, Peillon, S., additional, Dougniaux, G., additional, Bernard, E., additional, Autricque, A., additional, Pieters, G., additional, Rousseau, B., additional, Feuillastre, S., additional, Garcia-Argote, S., additional, Carvalho, O., additional, Malard, V., additional, George, I., additional, Lebaron-Jacobs, L., additional, Orsiere, T., additional, Uboldi, C., additional, Rose, J., additional, Sanles Sobrido, M., additional, Lambertin, D., additional, Vrel, D., additional, Decanis, C., additional, Liger, K., additional, Acsente, T., additional, and Dinescu, G., additional

Published
2019
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