https://repositorio.ufu.br/handle/123456789/5147 2026-04-23T16:19:04Z 2026-04-23T16:19:04Z https://repositorio.ufu.br/handle/123456789/48559 2026-03-21T06:26:20Z 2026-03-16T00:00:00Z

Title: Análise técnica e de viabilidade de um processo de pirólise por microondas Abstract: This study investigated the pyrolysis processes of the jatobá fruit peel. First was made the proximate analysis of biomass; from the proximate analysis results, the moisture, ash, volatile matter, and fixed carbon content were determined. From these values, the elemental composition of the jatobá fruit peel was determined using the Parikh, Shen, and Nhuchhen methodologies, in addition to the arithmetic mean of the three methodologies. From the elemental composition and characterization of the jatobá fruit peel, the atomic classification of the jatobá fruit peel was performed, and the atomic ratio was calculated using the van Krevelen diagram. The moisture content was 8.67% ± 0.09%, the ash content was 1.52% ± 0.01% on a dry basis, the volatile content was 80.71% ± 2.63% on a dry basis, and the fixed carbon fraction was 17.77% ± 2.63%. From the average of the three methodologies, it was possible to determine that the carbon content was 48.27% ± 0.46%, the hydrogen content was 5.91% ± 0.01%, and the oxygen content was 43.86% ± 0.34%. From the micropyrolysis tests, it was observed that alkaline catalysts such as potassium hydroxide and calcium oxide presented the best results, since these compounds favored the formation of hydrocarbons, which was explained by the high hydrocarbon content in the volatiles. Tests conducted with calcium oxide at 650 °C showed a hydrocarbon content in the volatiles of 15.0%, while tests conducted at 650 °C using potassium hydroxide showed a hydrocarbon content in the volatiles of 17.1%. It was also observed that the absence of higher temperatures favors hydrocarbon formation. Experiments involving microwave-assisted pyrolysis were performed using particles with diameters between 0.250 mm and 0.355 mm and particles with diameters between 0.106 mm and 0.180 mm; larger particles favored charcoal formation, while smaller particles favored bio-oil formation. Long duration experiments and temperatures between 550 °C and 620 °C are favorable to produce bio-oil. While temperatures between 451 °C and 550 °C are favorable for producing charcoal. Scanning electron microscopy images showed that the charcoal is much more porous and has a more irregular surface than the original biomass, indicating a larger surface area compared to the original biomass.

2026-03-16T00:00:00Z https://repositorio.ufu.br/handle/123456789/48523 2026-03-07T06:30:26Z 2026-02-05T00:00:00Z

Title: Extração de proteínas das folhas de ora-pronóbis (Pereskia aculeata) para desenvolvimento de novos produtos alimentícios Abstract: Ora-pro-nóbis (Pereskia aculeata) is a non-conventional food plant (PANC) widely distributed in Brazil and recognized for its high nutritional value, especially for the high protein content present in its leaves. Given the growing demand for alternative sources of plant-based proteins and the interest in developing new food ingredients, this work aimed to evaluate and optimize the extraction of proteins from ora-pro-nóbis leaves, aiming to obtain a protein concentrate with potential application in the food industry. Initially, the physicochemical characterization of the fresh leaves was carried out, revealing a high moisture content and significant protein concentration on a dry basis. Subsequently, the leaves were subjected to freeze-drying, grinding, and mucilage removal. Protein extraction was performed by alkaline extraction followed by isoelectric precipitation, and the effects of pH, temperature, and extraction time were evaluated using a central composite rotatable design (CCRD). The results demonstrated that the recovery of proteins from ora-pro-nóbis was efficient, allowing the production of concentrates with protein content between 18.85% and 30.51%. Optimization of the extraction process using DCCR allowed the identification of favorable operating conditions to maximize the percentage of protein in the extract, yield, and protein recovery. Determining the isoelectric point was fundamental for the proper conduct of the precipitation step, contributing to increased process efficiency. The obtained protein concentrate was subjected to freeze-drying and characterized in terms of its physicochemical and functional properties. Thus, the results obtained indicated that ora-pro-nóbis has high potential as an alternative source of vegetable proteins, contributing to the valorization of unconventional food plants (PANCs) and the development of new food products with greater nutritional value and sustainable appeal.

2026-02-05T00:00:00Z https://repositorio.ufu.br/handle/123456789/48325 2026-02-20T06:25:55Z 2026-02-13T00:00:00Z

Title: Formulação de fluidos de perfuração sintético leves empregando esferas ocas de vidro Abstract: Brazil is a leading oil and gas producer in Latin America, with vast reserves and a welldeveloped infrastructure. The advancement of offshore exploration in increasingly deep waters necessitates the development of drilling fluids with enhanced properties. These fluids must be capable of balancing the pressure differential between the hydrostatic column of seawater and the geological formation while minimizing environmental impact. With the gradual depletion of reservoirs at shallow and medium depths, drilling in ultradeep water has become crucial for continued production. However, these operations demand high-performance fluids that can withstand high pressures and temperatures, in addition to complex geological formations. In this context, hollow glass microspheres (HGMs) are being studied as promising additives for drilling fluids, enabling the viability of wells with narrow pressure windows. Due to their incompressibility, these microspheres allow for a reduction in fluid density without compromising their essential rheological properties. In this study, a Central Composite Design (CCD) was conducted to evaluate the influence of key variables—such as HGM concentration, viscosifier concentration, and oil-to-water ratio (%O/W)—on the properties of synthetic drilling fluid. The properties studied included L600, L300, L200, L100, L6, L3, fluid loss, and density. The filtration mechanism of an ultra lightweight, 6.2 ppg, 100% olefinic fluid containing HGMs was also investigated. The results demonstrated the viability of applying HGMs, highlighting their potential for formulating drilling fluids in geologically complex environments.

2026-02-13T00:00:00Z https://repositorio.ufu.br/handle/123456789/48287 2026-02-14T06:21:06Z 2025-09-30T00:00:00Z

Title: Metodologia integrada para cálculo de emissões por fonte energética: aplicação no setor agroindustrial

2025-09-30T00:00:00Z