Physics of cathode spots in vacuum arcs
Understanding of mechanisms of operation of cathodic spots of vacuum arc discharges, including the role of explosive electron emission, is a challenging topic of high scientific interest and importance for applications. We conducted this research on the suggestion of, and in collaboration with, colleagues from Siemens Corporate Technology (Erlangen, Germany), one of the aims being application of results to contacts of high-power vacuum circuit breakers.
Our main goal was to develop a comprehensive numerical model of cathodic spots of vacuum arcs, accounting for all the potentially relevant mechanisms: the bombardment of the cathode surface by ions coming from a pre-existing plasma cloud; vaporization of the cathode material in the spot, its ionization and the interaction of the produced plasma with the cathode; the Joule heat generation in the cathode body; melting of the cathode material and motion of the melt under the effect of the plasma pressure and the Lorentz force and related phenomena.
All phases of life of a spot have been investigated, from ignition to extinction. The latter is accompanied by emission of a droplet. No explosions have been observed, which disproves the reigning paradigm of ectons (explosive electron emission centers). The modeling results conform to experimental data on the net and ion erosion of copper cathodes of vacuum arcs. One of the papers on this topic, which has been published in Journal of Applied Physics, was selected by the Editors for promotion through the American Institute of Physics Publishing's Scilights project.
In the future, the developed model will be used for investigation of unipolar arcs in fusion devices and of cathode erosion in other types of gas discharges.
UMa participates in ENSEC, which is a European Union funded project, running between Nov. 2017 to May 2020, and it is focused on the development of a European Study Program for an International Master’s Degree for the Environmental Security Sector. This project has two UMa lecturers and a Technician participating in the project who are dedicated to the development of guidelines for users of the learnin(...)
APOGEO MAC - Agricultura de precisão para o melhoramento da produção de vinho na Macaronésia. Programa: PCT-MAC 2014-2020.
Caracterização e conservação dos principais recursos genéticos vegetais tradicionais e estratégicos da RAM. Programa: PRODERAM 2020.
IMPACT III: – Impacto da Tecnologia na Qualidade do Vinho Madeira. Programa: PROCiência2020.
AROMA: Novos designs de sensores em fibra ótica para a deteção de compostos de AROMA. Programa: CENTRO 2020 + FCT
Contribución al ahorro hídrico en cultivos estratégicos para el sector primario de Canarias y Madeira mediante la aplicación de productos y extractos naturales bioactivos con propiedades osmoprotectoras. Programa: MAC 2014-2020.
CASBio - Avaliação e monitorização da Agrobiodiversidade e da Sustentabilidade dos Agrossistemas nos novos cenários climáticos. Programa: Operativo Madeira 14-20 da RAM.
A docente da Faculdade de Artes e Humanidades da Universidade da Madeira (FAH-UMa), Cristina Santos Pinheiro, obteve aprovação para financiamento da Fundação para a Ciência e Tecnologia como Investigadora Responsável do Projeto “Gynecia: Rodrigo de Castro Lusitano e a tradição médica antiga sobre ginecologia e embriologia”, no valor de cerca de 202.000€.
O financiamento, por três anos, r(...)
Beautiful patterns on anodes of DC glow discharges have been observed for over a century. In addition to being of significant theoretical interest by themselves, self-organized patterns on liquid anodes of atmospheric pressure glow microdischarges reveal a non-trivial cancer-inhibiting capability.
Our goal was to compute self-organized patterns of spots on a flat metallic anode of a glow(...)
Bifurcations in the theory of current transfer to cathodes of dc discharges and transitions between different modes
Concentration of electrical current onto the surface of electrodes of gas discharges in well-deﬁned regions, or current spots, is often the rule rather than the exception. These spots occur on otherwise uniform electrode surfaces, a regime where one might expect a un(...)
Efficient methods of modelling of electric arcs in high-pressure environment are of high importance for many technical devices, and the interaction of arc plasmas with electrodes, in the first place, the cathode, is currently a bottleneck. This explains a surge of interest in plasma-electrode interaction inhigh-pressure arc discharges in the scientific community that has occurred over the past couple o(...)
GENHYMAPE - Genes and Hypertension in Madeira, financiado por “Intervir+ (European Regional Development Fund- FEDER)”, que pretende detetar uma associação entre polimorfismos de genes (candidatos à hipertensão arterial) e a existência da hipertensão arterial na Madeira.
GENEMACOR - Genes in Madeira and Coronary Disease, financiado por “Intervir+ (European Regional Development Fund- FEDER)”, que pretende investigar as causas genéticas (polimorfismos) da doença coronária na Ilha da Madeira.
Diversidade do Sistema HLA na População Portuguesa, desenvolvido entre 1999 e 2003 e financiado pelo Fundo Social Europeu através do Programa Operacional Plurifundos da Região Autónoma da Madeira.
Diversidade Genética do Sistema HLA em Populações Africanas (POCTI/BIA-BCM/60440/2004), em desenvolvimento desde Janeiro de 2005 e financiado pela FCT.
Enhancing Mathematics Learning @Free State (EML@FS) é um programa de formação em serviço de professores de matemática, cujo objetivo principal é contribuir para melhorar a aprendizagem dos alunos e desenvolver as suas habilidades matemáticas, destinado a professores de 4º grau do Free State Province – África do Sul. Com este propósito orientador, estabelecemos os seguintes objetivos: - Reforçar o conhe(...)
O Projeto Produção De Artefatos Educacionais Sociotecnológicos E Formação De Professores Em Rede constitui uma oportunidade de parceria do CIE-UMa e a Universidade do Estado da Bahia - UNEB (BR). Tem como objetivo compreender como e em que medida a produção colaborativa de artefactos educacionais sociotecnológicos estão articulados à cultura e aos processos identitários e se traduzem em experiências fo(...)
Projeto ANAM, 2011-2014, Estudo Perfil Passageiro, de António Almeida.
Encontro dedidado à Análise em dimensão infinita e aplicações. Em particular, equações diferenciais fraccionárias e análise de Mittag-Leffler.
Researchers at GAUMa are responsible for 5 new entrees in the new Encyclopedic Dictionary of Madeira: 1) Astronomy; 2) International Year of Astronomy 2009; 3) Astronomy Group of the University of Madeira; 4) William Kingdom Clifford; 5) William Thomson (Lord Kelvin).
Annual event - "Astronomy Week". This is an event which has been held since 2001 with the aim of, during a week, disclosing and promoting Astronomy alongside to the different schools in Madeira as well as the public in general.
Study of Primordial Black Holes (PBHs): PBHs may have formed during the early stage of the Universe. At GAUMa we study theoretically its creation mechanisms, distribution throughout the Universe and eventual detection. PBHs allow us to track the primordial Universe and are pointed as the sources of the recently detected gravitational waves.
Setup of the Astronomical Observatory on the Island of Madeira with the potential of using it for research work in collaboration with other institutions. It is also intended that the observatory be used for observation sessions by students from different schools in the island as well as by the public in general, and that it can work as a promotion vector for scientific tourism.
Subjects such as individual talent and collective intelligence, originality and cooperation will be worked on. In this context, research is justified because it is seen as a key strategy in the process of developing creative people and sustainable organizations.
A collection made in collaboration with the Baltazar Dias Theater, in the framework of the celebrations marking the 130th anniversary of its opening. The collection aims to disseminate the unpublished and forgotten works of the dramatic genre of Madeiran authors.
Project in collaboration with the Municipality of Funchal that intends to inform children and adolescents the results of the investigations carried out within the ambit of the DEM. Reviewing the knowledge about the archipelago, almost 600 years since its discovery, represents opening doors for the future. Consisting of ten volumes with themes from economics to urbanism, from literature to history, the (...)
A project in collaboration with the Municipal Theater Baltazar Dias and the Municipality of Funchal, that aims to disseminate to the general public the knowledge produced during the elaboration of the DEM. The conferences are of multidisciplinary nature, contemplating several monthly events. This event was classified by Jornal da Madeira, as the "cultural event of the year 2017", and will continue, in (...)
Integrated in the “Aprender Madeira” Project, the Encyclopedic Dictionary proposes to update, synthesize, expand, understand and disseminate, in a contemporary perspective and with scientific rigor and pedagogical sense, knowledge accumulated about Madeira, seeking to join in the wake of those who, over the past centuries, have researched and written about Madeira.
The online and printed edition of authors and other relevant works for the knowledge of the literary heritage of Madeira and for a renewed vision of Portuguese literature as a whole. The main objective is to provide bibliographies, data and primary sources for students, professors and researchers in the area, as well as to disseminate an important collection for literature and culture, for the history (...)