Unsteady blood flow with nanoparticles through stenosed arteries in the presence of periodic body acceleration

The effects of nanoparticles such as Fe304,Ti02, and Cu on blood flow inside a stenosed artery are studied. In this study, blood was modelled as non-Newtonian Bingham plastic fluid subjected to periodic body acceleration and slip velocity. The flow governing equations were solved analytically by using the perturbation method. By using the numerical approaches, the physiological parameters were analyzed, and the blood flow velocity distributions were generated graphically and discussed. From the flow results, the flow speed increases as slip velocity increases and decreases as the values of yield stress increases

Hierarchical bayesian methods for the marine sciences:analyses of climate variability and fish abundance

Tese de doutoramento, Ciências do Mar, 2010, Universidade de Lisboa, Faculdade de CiênciasOs radicais orgânicos são espécies importantes em quase todos os domínios daquímica e bioquímica. Contudo, apesar da sua existência ter sido documentadahá mais de uma centena de anos, uma fracção significativa da energéticadestas espécies é ainda desconhecida. Uma propriedade termoquímica crucialno estudo de um radical é a entalpia associada à quebra da ligação (BDE)que dá origem a esse radical. Estas BDEs podem ser obtidas experimentalmenteatravés de calorimetria fotoacústica (PAC). A química computacionaltambém pode ser utilizada para fazer previsões rigorosas desta propriedade termoquímica.Os métodos teóricos permitem ainda o acesso directo à estruturade radicais e compostos pais. Neste trabalho, PAC e química computacionalforam utilizadas conjuntamente para estudar a energética de radicais orgânicos.A entalpia de formação padrão do radical ciclopentadienilo e a BDE C H parao 1,3-ciclopentadieno foram reexaminadas. Foi avaliada a precisão de extrapolaçõespara base completa de CCSD(T) e a de métodos de optimização com basena teoria do funcional da densidade. De seguida foi efectuado um estudo detalhadoda energética do grupo alilo. Finalmente, foi estudado o efeito da tensãode anel em hidrocarbonetos cíclicos com cinco e seis membros e respectivosradicais.Organic radicals are important species in virtually every domain of chemistryand biochemistry. However, even though they have been known for morethan 100 years, the energetic data for radicals typically have large uncertaintiesor are missing. One crucial thermochemical property in the study of a radicalis the enthalpy associated with the bond cleavage (BDE) which originates thatradical. BDEs can be obtained experimentally with photoacoustic calorimetry(PAC). Computational chemistry also provides reliable estimates of thisthermochemical property. In addition, theoretical methods provide direct accessto the structure of radicals and their parent compounds. In this work bothPAC and computational chemistry were used to study the energetics of organicradicals. The standard enthalpy of formation for the cyclopentadienyl radicaland the 1,3-cyclopentadienyl C H BDE were re-examined. We proceeded toassess the accuracy of cost-efficient CCSD(T) complete basis set extrapolationschemes and density functional theory optimization methods for radicals. Adetailed analysis of the energetics of the allyl moiety was then conducted. Finally,the effect of ring strain on five- and six-membered ring hydrocarbons andrespective radicals was discussed

An Initial Framework Assessing the Safety of Complex Systems

Trabajo presentado en la Conference on Complex Systems, celebrada online del 7 al 11 de diciembre de 2020.Atmospheric blocking events, that is large-scale nearly stationary atmospheric pressure patterns, are often associated with extreme weather in the mid-latitudes, such as heat waves and cold spells which have significant consequences on ecosystems, human health and economy. The high impact of blocking events has motivated numerous studies. However, there is not yet a comprehensive theory explaining their onset, maintenance and decay and their numerical prediction remains a challenge. In recent years, a number of studies have successfully employed complex network descriptions of fluid transport to characterize dynamical patterns in geophysical flows. The aim of the current work is to investigate the potential of so called Lagrangian flow networks for the detection and perhaps forecasting of atmospheric blocking events. The network is constructed by associating nodes to regions of the atmosphere and establishing links based on the flux of material between these nodes during a given time interval. One can then use effective tools and metrics developed in the context of graph theory to explore the atmospheric flow properties. In particular, Ser-Giacomi et al. [1] showed how optimal paths in a Lagrangian flow network highlight distinctive circulation patterns associated with atmospheric blocking events. We extend these results by studying the behavior of selected network measures (such as degree, entropy and harmonic closeness centrality)at the onset of and during blocking situations, demonstrating their ability to trace the spatio-temporal characteristics of these events.This research was conducted as part of the CAFE (Climate Advanced Forecasting of sub-seasonal Extremes) Innovative Training Network which has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 813844