https://repositorio.uema.br/jspui/handle/123456789/1907 Wed, 01 Apr 2026 19:52:25 GMT 2026-04-01T19:52:25Z https://repositorio.uema.br/jspui/handle/123456789/5442 Título: Problema da difusão em meio poroso via cálculo fracionário Abstact: Throughout history, renowned researchers have dedicated themselves and their studies to investigate, understand and describe nonlinear diffusion processes, using analytical, numerical and computational tools. In this work, we present a problem of nonlinear anomalous diffusion in porous media and aim to present Lie symmetry transformation groups as an alternative to solving the diffusion problem. Initially, a study was carried out on fractional calculus and its main operators, where we point out definitions, theorems, properties and applications. Fractional calculus allows us to describe natural characteristics more precisely, thus obtaining a greater amount of information linked to nonlocal operators, then called the memory effect. An analysis of anomalous fractional diffusion in porous media was carried out, where the problem of nonlinear fractional diffusion in time-space was addressed. Another important point presented here is the Lie point transformation groups, which we use as an alternative to the diffusion problem, since Lie symmetries prove to be a very important tool as it allows the transformation of a PDE into an ODE. We apply Lie symmetries to the discovery of diffusion in fractional porous media in terms of Riesz derivatives, including the Weyl derivative. And we demonstrate that the results can be understood for the fractional derivative in terms of the function È. We emphasize that the study of anomalous diffusion has been increasingly deepened and its concept applied in several fields such as diffusion in plasmas, diffusion in turbulent fluids, fluid transport in porous media, diffusion in fractals, anomalous diffusion on liquid surfaces and analysis of heartbeat histograms in healthy individuals, among other physical systems. Keywords: Anomalous Diffusion, Fractional Calculus, Fractional Diffusion in Porous Media, Lie Points Wed, 06 Nov 2024 00:00:00 GMT https://repositorio.uema.br/jspui/handle/123456789/5442 2024-11-06T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/5388 Título: Estudo teórico das propriedades termodinâmicas e cinéticas nas reações de combustão do diborano como combustível de foguete Abstact: A study was carried out on the thermodynamic and kinetic properties of the combustion reactions of diborane as rocket fuel. To this end, it aims to understand the characteristics and thermodynamic and kinetic properties of the thermal decomposition of high energy materials in order to develop a mechanism of chemical combustion reactions. From the methodological point of view, the geometrization of the molecules was modeled using the Gaussian9 software, considering the bonds of each molecule of interest B-B, B-H, B-О, О-О, Н-H, O-H, mentioned in the isodesmic reactions. It is evident that the optimizations of the equilibrium molecules in the ground state were performed using the functional B3LYP model of DFT for the geometries of the molecules. It is stated that the calculations of the reactions were computed at different temperatures of 100K, 298K, 500K, and 1000K, thus it was possible to extract from the Gaussian output file, the thermodynamic properties such as enthalpy variation, Gibbs free energy, and equilibrium constant. The equilibrium constants Keq were computed from the thermodynamic properties of the reactants and products as a function of temperature, and the enthalpy variation (AH) was calculated based on the difference between the enthalpies of the products and reactants. It reinforces that in the Density Functional Theory (B3LYP) the base set cc-pVTZ (Triple Zeta) was used to determine the enthalpy of formation of neutral and critical species in thermal decomposition. The presentation of the computational data of the molecular geometries was presented in the form of tables and graphs. It was concluded that the isodesmic reaction technique is very successful in determining the types of combustion reactions, and helped us to clarify which of the reactions are involved in the absorption of the heat produced during the process. It was observed that reactions I, II and III are reactions with a high value of the Gibbs energy variation (negative) and that release a high value of energy to the medium Mon, 18 Dec 2023 00:00:00 GMT https://repositorio.uema.br/jspui/handle/123456789/5388 2023-12-18T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/5364 Título: Efeitos termo-elétricos e magnéticos das monocamadas TMDs 1T’ – RuWTe2 e 1T’ – WTe2 via simulação computacional Abstact: Transition metal dichalcogenides (TMDs) are chemical compounds consisting of two chalcogen atoms (Te, Se or S) connected by covalent bonds to a transition metal atom, having the structural form MX2. In this research, modeling and computer simulation were carried out, followed by an analysis of the physical properties of monoclinic monolayers (1T’) of tungsten ditelluride (WTe2) and tungsten-ruthenium ditelluride (RuWTe2) TMDs, the latter replacing aWatom with a Ru atom in the primitive cell, from density functional theory (DFT) formalism, mainly considering the generalized gradient approximation (GGA) and the HSE06 hybrid functional for bandgap estimation, from nanostructures in their minimum energy state. The lattice parameters of the proposed 1T’−RuWTe2 TMD are compatible with the 1T’−WTe2 TMD already known in literature. The estimated bandgap for 1T’−RuWTe2 was 0.50 and 0.35 eV, for the spin up and down bands, respectively, characterizing it as a semiconductor, while 1T’−WTe2 showed conductor characteristics. As for their magnetic nature, these TMDs showed ferromagnetism, with 1T’ − RuWTe2 showing an apparent tendency towards ferrimagnetism. The density of partial states, thermodynamic potentials and thermal capacity were also analyzed, highlighting the potential for synthesis and estimation of new Technologies such as thermo-electric and magnetic nanodevices of the 1T’ − RuWTe2 TMD Mon, 01 Jan 2024 00:00:00 GMT https://repositorio.uema.br/jspui/handle/123456789/5364 2024-01-01T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/4970 Título: Universidade VoIP: do legado às redes totalmente IP Abstact: Continuing the research on Universidade VoIP, this study expanded its application to public sector institutions, focusing on E-TEC and IFMA - Advanced Campus of Rosário. The study aimed to demonstrate the feasibility of IP telephony in these environments, considering the need for adaptation of analog telephony, which is still present in various locations. To achieve this, Asterisk was implemented and tested on two different operating systems, Windows and Linux, evaluating its functionality on different platforms. Additionally, a no-code based application was developed, enabling messaging, audio conferencing, and video conferencing. As a result, a fully functional VoIP server was obtained, adaptable to both local networks (LAN) and wide-area networks (WAN), ensuring efficient communication between legacy systems and IP infrastructure. The solution demonstrated that IP telephony can be progressively integrated, preserving connectivity and expanding institutional communication possibilities. Thus, the potential of IP Telephony is reaffirmed as a modern and accessible alternative for the evolution of communication systems Fri, 28 Feb 2025 00:00:00 GMT https://repositorio.uema.br/jspui/handle/123456789/4970 2025-02-28T00:00:00Z