Magnetic field-induced insulating behavior in highly oriented pyrolitic graphite

We propose an explanation for the apparent semimetal-insulator transition observed in highly oriented pyrolitic graphite in the presence of magnetic field perpendicular to the layers. We show that the magnetic field opens an excitonic gap in the linear spectrum of the Coulomb interacting quasiparticles, in a close analogy with the phenomenon of dynamical chiral symmetry breaking in the relativistic theories of the 2+1-dimensional Dirac fermions. Our strong-coupling appoach allows for a non-perturbative description of the corresponding critical behavior

Plataforma peopleminin : recruitment analytics e gestão do conhecimento

Project Work presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Knowledge Management and Business IntelligenceO uso de analytics é ainda algo pouco usual no campo da gestão de pessoas, particularmente no que respeita ao recrutamento. A dinâmica de um processo seletivo considera o constante desafio da busca e encontro do candidato mais compatível à vaga a ser preenchida. Há diversas lacunas observadas nesse contexto, em especial quanto à: facilidade de acesso a candidatos potencialmente ideais; aderência entre candidato e vaga; capacidade do recrutador na devolutiva quando da não continuidade deste candidato no processo, dado o excessivo volume de inscrições. Soluções de variadas naturezas já foram descritas, notadamente na forma de teorias com foco prevalentemente acadêmico. Entretanto, um problema real requer resposta empírica e onde haja a experiência da tentativa e erro. A referida resposta resulta na plataforma Peopleminin®, a tornar possível um recrutamento assertivo, baseado na gestão do conhecimento combinada a people (recruitment) analytics. Em um ambiente de vasta oferta de aplicações website e mobile para recrutamento, a plataforma Peopleminin® diferencia-se pelo algoritmo único que conjuga conhecimentos, comportamentos e cultura na análise da compatibilidade entre candidato e vaga. A ferramenta destaca-se quando comparada às demais opções existentes pela sua lógica inversa, a fazer com que a vaga procure o candidato e não o oposto. Ao mesmo tempo, propicia a eliminação das lacunas anteriormente mencionadas, assim como é capaz de ser a ponte entre conceito e prática. Somente o futuro dirá se a plataforma é disruptiva, inovadora ou mera adaptação do que existe

Numerical modeling of laminar-turbulent transition in an interconnecting compressor duct

With the purpose of meeting the ambitious environmental targets set by the European Union (EU) in 2019, after the European Green Deal, new sustainable fuels need to be adapted by the aviation industry. Hydrogen stands out to be a promising candidate due to its CO2-free combustion, and higher energy density compared to kerosene. The main disadvantages of LH2 are its lower density compared to kerosene and the required cryogenic storage temperature, which affects propellant feed system size, mass, and insulation requirements. Nevertheless, the cryogenic temperatures coupled with its high specific heat capacity makes LH2 a formidable coolant, of which engine precooling, intercooling, and recuperation are potentially beneficial applications for aero engines. The focus of this paper is on how to model the vane surfaces of an Intermediate Compressor Duct (ICD) using CFD for the purpose of intercooling to support and prepare for future validation work using the Chalmers low pressure compressor rig. This study will analyze the behavior of different CFD transition models in the prediction of laminar-turbulent transition, mesh dependency, the impact of wall temperature, and the effect of conduction in the vane material. CFD simulations using the Gamma-Theta and Intermittency transition models showed very similar results and highlighted the need of well-refined computational grids to reach mesh independence for pressure loss, heat flow, and transition onset and length. A parametric study where the vane wall temperatures were decreased showed that transition was delayed for decreasing wall temperatures and that the length of the transition zone decreased as well. The results of a conjugated CFD model of a cryogenically cooled ICD vane showed that using only the surface of the vane for exchanging heat led to a relatively small decrease in core air total temperature. Therefore, the merit of using the existing aerodynamic surfaces of the ICD for heat transfer needs to be investigated further by including the hub and shroud surfaces as well, or increasing surface area further by using fins