https://repositorio.ufpb.br/jspui/handle/tede/440 PPGCEM 2026-08-15T05:50:18Z https://repositorio.ufpb.br/jspui/handle/123456789/38570 Título: Compósitos ferromagnéticos de PDMS e Liga Heusler Ni44Mn44Sn9Cu3 Autor(es): Soares, Clarice Cardoso Orientador: Oliveira, Danniel Ferreira de Abstract: Heusler Ni-Mn-Sn alloys have been widely studied because they present multifunctional properties associated with phase transitions controlled by the magnetic field, such as the metamagnetic shape memory effect, the magnetocaloric effect and exchange polarization. These properties are promising for applications such as magnetic actuators, magnetic refrigeration and high-efficiency sensors. Changing the composition by replacing its components with a fourth element, such as Cu, is an effective way to adapt their properties. However, these materials have limitations such as low machinability, mechanical brittleness and instability of functional properties after processing. To overcome these problems, a strategy involves the production of polymer matrix composite materials reinforced with these metal alloys. In this work, PDMS matrix composites reinforced with Heusler Ni44Mn44Sn9Cu3 alloy particles were produced. The developed materials showed preservation of the polymer chemical structure, thermal stability, reduction of mechanical resistance with the addition of metallic particles, greater flexibility compared to pure Heusler alloys, increase of remanent magnetization and saturation magnetization according to the increase of the alloy content, resulting in improvement of the ferromagnetic response. Thus, the results obtained indicate that the developed composites are favorable candidates for use in flexible devices that require tunable magnetic properties. Editor: Universidade Federal da Paraíba Tipo: Dissertação 2025-08-27T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38564 Título: Caracterização físico-química das argilas caulim (branca) e bentonita (verde) associadas à polpa de acerola (Malpighia emarginata dc) como ativos para o desenvolvimento de uma formulação cosmética facial Autor(es): Martins, Poliana Soares Orientador: Ferreira, Heber Sivini Abstract: There is a growing consumer preference for natural raw materials, such as clays and fruits, in the development of cosmetic products. Clays, composed of minerals, are widely used in cosmetics due to their high adsorption rate, abundance in nature, low environmental impact, low risk of toxicity, high surface area, and excellent ion exchange capacity. Among the most common clays in cosmetics are kaolin (white) and bentonite (green), which offer benefits such as cleansing, adsorption of impurities, toning of the epidermis, hydration, and treatment of dermatitis and acne. Acerola, a fruit rich in vitamin C, has also been widely used in the cosmetics sector for its effectiveness in combating free radicals, in addition to its properties in lightening blemishes, increasing skin elasticity, and photoprotection, due to its high antioxidant potential. The objective of this study was to characterize the physicochemical properties of kaolin (white) and bentonite (green) clays combined with acerola pulp, aiming at their use as active ingredients in a cosmetic facial cream formulation. The clays underwent purification and drying processes via spray dryer, and the acerola fruits underwent pulp removal. Subsequently, they underwent microbiological analysis and were characterized according to their physicochemical properties, revealing a clayey material with a pH above the skin pH, low unit content, fine particle size after purification and drying, and rich in minerals according to XRF analysis. Bentonite presented better results in terms of density, porosity, and flow angle. In the TG and DTA analyses, kaolin showed endothermic peaks, and bentonite showed endothermic and isothermal peaks. The acerola pulp had an acidic pH and high vitamin C content. The clays and acerola pulp showed good application properties in a facial cream formulation with 0.5%, 1.5%, and 3.0% of each active ingredient equally incorporated into the cosmetic. The formulation was subjected to microbiological testing and analyzed for organoleptic, physicochemical, and rheological properties. The cosmetic presented good stability and underwent sensory analysis and in vivo tests approved by the ethics committee. Rheological analysis indicated that the formulation exhibited non-Newtonian pseudoplastic behavior, and the 3% active ingredient concentration best fit the rheological model. In microbiological analyses, the active ingredients did not show bacterial or fungal colony growth. The facial cream, in turn, showed bacterial growth within the limits permitted by law. The facial cream containing clays and acerola pulp obtained promising results in terms of hydration, pores, and skin elasticity. In the sensory analysis, oiliness, firmness, and overall evaluation were the best-rated attributes. In terms of purchasing behavior, it was found that 50% of evaluators would buy the clay cream with acerola. Thus, this study provides relevant information on the use of clay and acerola pulp, demonstrating their benefits for the skin through facial creams containing these active ingredients. This suggests a potential product for application as a facial cream, a promising alternative for the development of innovative, effective, and sustainable cosmetic products. Editor: Universidade Federal da Paraíba Tipo: Tese 2025-06-30T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38555 Título: Avaliação das características termoelétricas e termorresistivas da matriz semicondutora de óxido de zinco dopado com manganês em diferentes concentrações Autor(es): Nascimento, Jefferson Lira Orientador: Torquato, Ramon Alves Abstract: In the current context, scientific and technological development is fundamental to the needs of a modern society, such as information capacity, data speed, energy autonomy, miniaturization of components and equipment, lower production costs, and more efficient systems. In this vision and reality, the world of semiconductor materials plays a fundamental, even essential, role. Therefore, the study of these materials will always have a scientific and technological appeal that attracts the attention of those who conduct research. When dealing with sensing systems and the production of electrical energy, it is something that sparks interest in the results that will be generated. Therefore, in this work we used the zinc oxide (ZnO) semiconductor matrix, which has a wide band gap of ≈ 3,37 eV, so that through the doping process we could evaluate the effect on the thermoresistive and thermoelectric response of this matrix doped with the transition metal manganese (Mn), at concentrations of x = 0,1; 0,2; 0,3; 0,4 and 0,5 mol of Mn+2, in the Zn+2 substitution process, in the Zn1-xMnxO system, using the combustion reaction synthesis route for the production of the systems. The produced systems were calcined, beneficiated, pressed, and sintered at a temperature of 1100 °C at a rate of 10 °C/min. After preparation, their microstructure was analyzed using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) with EDS, band gap analysis using Ultraviolet Spectroscopy (UV-Vis), and thermoresistive and thermoelectric responses. The results showed the formation of a second phase, with a dense material whose average particle size increased with increasing Mn+2 concentration. Considering a theoretical value of 3,37 eV for pure ZnO, the band gap width was affected by the addition of the dopant, with the highest value obtained being 2,91 eV for x = 0,3 mol of Mn+2 and the lowest value found being 2,72 eV for x = 0,5 mol, but preserving the semiconductor characteristic even with doping. In the thermoresistive results, a thermistor with a negative thermal coefficient (NTC) was produced, where the minimum β found was at x = 0,1 mol of Mn+2 with 4334K for the 75°C to 100°C test, and the best for x = 0,2 mol Mn+2 resulting in 6396K in the 50°C – 100°C test. Therefore, the results obtained proved satisfactory for this initial study, where we were able to produce high-quality NTC thermistors, reinforced by the ln(ρ) x 1000/T(K) graph, which also demonstrated specific temperature ranges within those analyzed, in which β exceeded commercial values. In the thermoelectric results, we obtained values between -835.53 μV/°C and -57.62 μV/°C and -72.02 μV/°C to - 1.02 μV/°C for pure ZnO doped with 0.5 mol of Mn at temperatures of 50°C and 100°C, respectively. Editor: Universidade Federal da Paraíba Tipo: Dissertação 2026-02-09T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38278 Título: Desenvolvimento e avaliação in vitro de sistemas de liberação controlada de drogas para o tratamento da leishmaniose cutânea à base de nanofibran de PLA/PEO/ANPOTERICINA B produzidas por solution blow spinning (SBS) Autor(es): Ferreira, Kaline do Nascimento Orientador: Medeiros, Eliton Souto de Abstract: Cutaneous leishmaniasis (CL) is an infectious parasitic disease caused by the protozoan of the Leishmania genus, which promotes ulcers in exposed areas of the skin. Amphotericin B (AmB) is one of the drugs used in the treatment. However, its clinical use has limitations intravenously because of its high toxicity and low solubility, making it attractive to investigate vehicles for topical application as a safer way. Thus, in this work a nanostructured topical drug delivery system (TDDS) was proposed using the solution blow spinning (SBS) technique. Fibers of blends of poly(ethylene oxide), PEO, and poly(lactic acid), PLA, with and without AmB were produced by SBS. PEO/PLA fibers in two different weight ratios 50:50 and 70:30, with 0, 0.25, and 1.0% AmB were produced in the form of mats that were morphologically characterized by scanning electron microscopy ( SEM), thermally by thermogravimetry (TG) and differential scanning calorimetry (DSC) and microstructurally by Fourier transform infrared spectroscopy (FTIR) and the degree of hydrophobicity of its surface was verified through the contact angle. The determination of the AmB release profile, the efficiency of incorporation and the drug load were evaluated by spectroscopy (UV-Vis). The degree of swelling of the samples was determined. The release curves were fitted by kinetic models to provide crucial information about the function of the material systems that constitute them. In vitro assays of leishmanicidal activity were determined in promastigote forms of Leishmania amazonensis. The results show that the systems produced by SBS consist of rough fibers for all compositions. AmB was incorporated into the nanofibers and the materials were shown to be thermally stable within the physiological temperature range. The significant increase in drug incorporation occurred in structures with higher proportions of PLA, which has hydrophobic character, higher contact angles, however, the maximum controlled release (88%) after 14 days was found in samples with higher proportions of PEO and AmB . The Peppas-Sahlin model showed the best mathematical fit (R2 ≥ 0.95). The 50:50 samples showed non-Fickian transport, indicative of the combination of drug diffusion mechanisms and polymeric erosion. On the other hand, dressings with higher proportions of PEO showed the Fickian diffusion mechanism, in addition to higher degrees of swelling. All the nanostructured topical drug delivery system with AmB showed leismanicidal activity within 72 h, the highest activities were found for samples with 1.00% of the drug. The results obtained suggest that TDDS control the availability of AmB and have leishmanicidal activity with potential to be used in the local treatment of CL. Editor: Universidade Federal da Paraíba Tipo: Tese 2022-03-23T00:00:00Z