DSpace Community:https://repositorio.ufu.br/handle/123456789/217592026-04-23T11:44:41Z2026-04-23T11:44:41ZA prova dos noves ou noves forahttps://repositorio.ufu.br/handle/123456789/485102026-03-07T06:30:20Z2025-09-19T00:00:00ZTitle: A prova dos noves ou noves fora2025-09-19T00:00:00ZExplorando a fatoração de polinômios do segundo grau com as mãos: um recurso tátil para a educação inclusivahttps://repositorio.ufu.br/handle/123456789/485022026-03-07T06:29:17Z2025-05-15T00:00:00ZTitle: Explorando a fatoração de polinômios do segundo grau com as mãos: um recurso tátil para a educação inclusiva
Abstract: This study aims to develop, analyze, and validate a tactile didactic tool for teaching the factorization of second-degree polynomials to students with visual impairments. The choice of theme stems from the identified scarcity of algebra-focused materials within Inclusive Education contexts, as observed by the author during his teaching internship. This experimental research involved the modeling and 3D printing of three versions of a manipulable artifact, following an iterative process of creation, internal testing, and validation with visually impaired participants. The analyses were based on the SAI model (Instrumental Activity Situations), highlighting the interactions between subject, object, and instrument throughout the process of instrumental genesis. The results showed that the material supports understanding of factorization through the spatial organization of the pieces and has potential to assist in solving quadratic equations. However, it has limitations, such as its restriction to polynomials with integer and factorable coefficients. It is concluded that the tool represents an accessible and promising alternative for teaching algebra in inclusive educational settings.2025-05-15T00:00:00ZNanopartículas semicondutoras: síntese e caracterizaçãohttps://repositorio.ufu.br/handle/123456789/484632026-03-04T06:26:25Z2025-05-20T00:00:00ZTitle: Nanopartículas semicondutoras: síntese e caracterização
Abstract: Semiconductor nanomaterials play a fundamental role in the manufacturing of modern electronic devices, including LEDs, displays, fiber-optic communication systems, and lasers. Technological development requires a constant search for new materials and synthesis methods. In this Undergraduate Thesis (TCC), nanoparticles based on Carbon Dots (CDs) and group II-VI semiconductors we synthesized and characterized, aiming to explore their optical and electronic properties. Optical characterization was performed using techniques such as photoluminescence (PL), photoluminescence excitation spectroscopy (PLE), and absorbance measurements, enabling a detailed investigation of light absorption and emission mechanisms, as well as the coupling between electronic states. The PL spectra were analyzed through deconvolution into Gaussian curves, which allowed the identification and separation of contributions from different emissive centers present in the Carbon Dots. To evaluate the stability of the samples' optical properties, we studied the fitting parameters of the luminescence spectrum immediately after synthesis and then six months later. We observed that some of these fitting parameters vary over time, while others tend to remain constant, which is of crucial importance for applications of these structures in optoelectronic devices. Finally, the dependence of PL spectra on the excitation wavelength was investigated, providing relevant conclusions about the nature of the emissive sites and their characteristic energies. This approach allowed us to distinguish between emissions related to surface states and transitions involving the core of the nanoparticles. We believe this work was beneficial for our academic development, providing practical and theoretical knowledge in the synthesis and characterization of new semiconductor materials, a field of critical importance for the advancement of nanotechnology.2025-05-20T00:00:00ZSíntese e caracterização de pontos quânticos de carbono a partir da pirólise da palha de milho e oxidação dos produtoshttps://repositorio.ufu.br/handle/123456789/477472025-11-26T06:19:11Z2025-05-07T00:00:00ZTitle: Síntese e caracterização de pontos quânticos de carbono a partir da pirólise da palha de milho e oxidação dos produtos
Abstract: This study aims to produce carbon dots (CDs) from corn husks using pyrolysis as the synthesis method. The corn husks were subjected to a temperature of 300 °C in a muffle furnace, with 3 mL of nitric acid (HNO₃) used as the oxidizing agent. Temperature and exposure time were key variables in the formation of CDs. Six samples were prepared with treatment durations of 1, 2, and 3 hours to analyze structural and optical changes. Characterization by Fourier-transform infrared spectroscopy (FTIR) indicated the presence of nitrogen-containing functional groups, confirming the carbonization of the material. Ultraviolet-visible (UV-Vis) absorption spectra showed bands between 270 and 340 nm related to π-π* transitions of C=C bonds in the graphitic structure, and a band around 350 nm associated with n-π* transitions of carbonyl (C=O) groups. Additionally, luminescence emission was observed when the samples were excited at specific wavelengths, with varying emission intensities—ranging from low 69 (u.a) to high 318 (u.a) depending on particle size and quantum confinement effects, which influence the optical behavior of the CDs.2025-05-07T00:00:00Z