DSpace Community:http://hdl.handle.net/10174/252024-03-29T05:35:48Z2024-03-29T05:35:48ZThe Global Heat Flow Database: Update 2023Fuchs, SvenNeumann, FlorianNorden, BenBeardsmore, GraemeChiozzi, PaoloColgan, WilliamAnguiano Dominguez, Ana PaulinaDuque, Maria Rosa AlvesOjeda Espinoza, Orlando MiguelForster, FlorianForster, AndreaRolandone, FrédériqueVerdoya, MassimoWu, Jyun-Nahttp://hdl.handle.net/10174/365222024-03-22T10:30:04Z2023-01-01T00:00:00ZTitle: The Global Heat Flow Database: Update 2023
Authors: Fuchs, Sven; Neumann, Florian; Norden, Ben; Beardsmore, Graeme; Chiozzi, Paolo; Colgan, William; Anguiano Dominguez, Ana Paulina; Duque, Maria Rosa Alves; Ojeda Espinoza, Orlando Miguel; Forster, Florian; Forster, Andrea; Rolandone, Frédérique; Verdoya, Massimo; Wu, Jyun-Na
Abstract: The data publication contains the compilation of global heat-flow data by the International Heat Flow
Commission (IHFC; www.ihfc-iugg.org) of the International Association of Seismology and Physics of
the Earth's Interior (IASPEI). The presented data update 2023 contains data generated between 1939
and 2022 and constitutes the first intermediate update benefiting from the global collaborative assessment and quality control of the Global Heat Flow Database running from May 2021 (http://assessment.ihfc-iugg.org)2023-01-01T00:00:00ZProblems associated with the contrast between thermal and mechanical properties of materialsDuque, Maria Rosahttp://hdl.handle.net/10174/364592024-03-19T15:03:17Z2023-01-01T00:00:00ZTitle: Problems associated with the contrast between thermal and mechanical properties of materials
Authors: Duque, Maria Rosa
Abstract: The present work consists in the study of thermal and mechanical properties of a body
consisting of equal volume of two materials with different thermal and mechanical
properties, placed in physical contact. The materials are subjected to a common thermal
source but, due to their density and specific heat capacity, their temperatures will suffer
different variations. This work studies the changes occurring near the contact zone of the
two materials. In addition to different volume increases (pressure increases) in the two
materials, different values of thermal conductivity must be considered and shear stresses
of thermal origin, with different values in the two materials must be studied near the
contact zone. The work studies the changes observed near the contact area of the two
materials considering different values of heat supplied . Changes of thermal conductivity
and specific heat capacity values with temperature are considered but variations with
pressure increase are not. The hypothesis of introducing a third element (water) into pre existing cracks dilated with the initial heating is also studied.2023-01-01T00:00:00ZAlteração de temperatura do solo associada a variações de intensidade de fontes internasDuque, Maria Rosahttp://hdl.handle.net/10174/364582024-03-19T15:01:34Z2024-01-01T00:00:00ZTitle: Alteração de temperatura do solo associada a variações de intensidade de fontes internas
Authors: Duque, Maria Rosa
Abstract: A temperatura medida no solo abaixo da superfície, resulta das transferências de energia
térmica proveniente do Sol propagando-se por condução até ao ponto onde é feita a
medição, e energia térmica proveniente do interior da Terra que se propaga por condução,
em sentido oposto, até à superfície. O presente trabalho fala apenas desta última
transferência de energia. As fontes térmicas no interior da Terra são essencialmente
energia proveniente de zonas mais internas, relacionada com o processo de formação e
desenvolvimento do planeta, reações químicas e fontes radioativas. Sabendo a
concentração dos isótopos radioativos responsáveis pela libertação de energia térmica,
235U, 238U, 232Th e 40K, é possível obter-se a “produção de calor” associada ao decaimento
radioativo. A diminuição secular do fluxo de calor proveniente do manto pode ser obtida
através de uma lei exponencial com uma constante de decaimento de 3 G ano-1
. Utilizando
a informação referida, tendo em conta os fluxos de calor proveniente do manto nos tempos
atuais, podemos obter informação sobre o fluxo de calor e a temperatura no passado. O
presente estudo remonta até há 4 milhões de anos (idade atribuída aos Australopithecus)
terminando cerca de 300 000 anos atrás (idade dos vestígios mais antigos de Homo
Sapiens). As diferenças entre o fluxo atual na superfície e o fluxo no passado permitem
inferir a sua influência na camada de ar junto ao solo e também junto ao fundo oceânico.2024-01-01T00:00:00ZAnomalias magnéticas, alturas do geóide e variações de temperatura na plataforma do SW de PortugalDuque, Maria Rosahttp://hdl.handle.net/10174/364452024-03-18T16:38:18Z2023-05-31T23:00:00ZTitle: Anomalias magnéticas, alturas do geóide e variações de temperatura na plataforma do SW de Portugal
Authors: Duque, Maria Rosa
Abstract: Geoid height values obtained with models EGM 84, EGM96 and EGM 2008 for the region under study present significant changes, ocurring in relatively short time intervals, which can be interpreted as density changes associated with temperature variations in the region. In the present work, studies were made with data of the geomagnetic field (average hourly values) obtained at the Magnetic Observatory of Coimbra, San Fernando and Almeria, and it was concluded that anomalies detected on February 27 of 1969 can be interpreted as being obtained by suprposition of additional magnetic fields (in relation to days 25 and 26th), initially with mainly horizontal component and later with mainly vertical component. These additional fields may be associated with ion movements with mainly vertical direction followed by mainly horizontal direction. The variation in the direction of the geomagnetic field and the associated electric field lines could lead to reorientation of dipolar molecules and temperature increase in the region, whixh may have caused opening cracks and fractures already existing in the region, facilitating the entry of large amounts of water to deep zones, with relatively high speeds and temperatures.2023-05-31T23:00:00Z