Dissertação de Mestrado em Engenharia Eletrotécnica e de Computadores ; O mundo que nos rodeia encontra-se repleto de tecnologia que, cada vez mais, nos proporciona conforto, apoio, segurança e rentabilidade. Foi nessas vantagens que encontrei grande admiração pela tecnologia. No meu percurso estudantil tive o privilégio de estudar numa Escola que me ofereceu a oportunidade de criar protótipos de produtos que ...
Carbo-nitride synthesis was undertaken using a solar furnace at PSA in flowing N2/Ar gas mixture under total pressure 1 atm and processing temperature T = 1600ºC for some d-group transition elements (Ti; Zr, V, Nb, Mo, W) starting from 1.5G/M (graphite/metal powder mixture with mole ratio 1.5:1) compact to ensure co-presence of free carbon with the reaction product. Clear X-ray diffraction (XRD) evidence of for...
Flowing gaseous ammonia NH3 with suppressed extent of dissociation (un-cracked NH3) is acknowledged to function as a powerful nitriding medium to realize formation of metal nitride MNx with considerably high N/M ratio x that cannot be achieved through reaction of M with N2 gas. For example, mono-nitride d-MoN of Mo and e-FeNx phase of Fe with x = 0.33 ˜ 0.50 (i. e. hypo-stoichiometric sub-nitride e-Fe2N) were r...
We consider the dynamical system (A,T), where A is a class of differentiable functions defined on some interval and T:A→A is the operator Tφ:=foφ, where f is a differentiable m-modal map. For the particular case of f being a topologically exact map we study the growth rate of critical points of the iterated functions. Considering functions in A whose critical values are periodic points for f, we analyze the evo...
We consider the dynamical system (A,Tf), where A is a class of differentiable real functions defined on some interval and Tf:A→A is an operator Tf:=foφ, where f is a differentiable m-modal map. If we consider functions in A whose critical values are periodic points for f then, we show how to define and characterize a substitution system associated with (A,Tf). For these substitution systems, we compute the grow...
We show that every point x0 2 [0; 1] carries a representation of a C -algebra that encodes the orbit structure of the linear mod 1 interval map f ; (x) = x + . Such C -algebra is generated by partial isometries arising from the subintervals of monotonicity of the underlying map f ; . Then we prove that such representation is irreducible. Moreover two such of representations are unitarily equivalent if and onl...
We study the iteration of a quadratic family in the algebra of 2 × 2 real matrices, parameterized by a matrix C. We analyze and classify the existing cycles (periodic orbits) and their dependence on the parameter matrix. We discuss how new dynamical phenomena occur as a consequence of the noncommutativity of the matrix product. In particular, we show that the commutator of the initial condition with parameter m...
A obesidade infantil apresenta-se como um dos mais sérios problemas de saúde pública, quer no espaço Europeu, quer no resto do mundo. A taxa de crescimento desta doença tem-se mantido constante, acrescentando 400000 crianças por ano, aos já existentes 40-50 milhões de crianças com excesso de peso. A Organização Mundial da Saúde (OMS), no seguimento da aprovação da Carta Europeia de Luta Contra a Obesidade, lanç...
Tese de mestrado. Faculdade de Engenharia. Universidade do Porto. 2000
Dissertação apresentada para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores, na Faculdade de Engenharia da Universidade do Porto, sob a orientação do Prof. Doutor Adriano da Silva Carvalho
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