Teses em Engenharia de Recursos Naturais da Amazônia (Doutorado) - PRODERNA/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/4045

O Doutorado Acadêmico inicou-se em 2006 e pertence ao Programa de Pós-Graduação em Engenharia de Recursos Naturais da Amazônia (PRODERNA) do Instituto de Tecnologia da UFPA (ITEC) da Universidade Federal do Pará (UFPA).

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Agora exibindo 1 - 5 de 5

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Compósitos híbridos reforçados com tecidos de curauá, carnaúba e aramida com aplicações em blindagem balística
(Universidade Federal do Pará, 2023-01-31) OLIVEIRA FILHO, Edwillson Gonçalves de; CANDIDO, Verônica Scarpini; http://lattes.cnpq.br/8274665115727809
The development of effective ballistic armor systems is essential to ensure human and vehicle protection. These shields are usually made up of different materials, such as fiber-reinforced polymeric composites, which are used when a good weight/ballistic protection ratio is desired. In addition, the search for ecologically correct materials, which associate good mechanical performance with sustainability, has been very frequent nowadays. The present work was directed to the study of the mechanical and ballistic properties presented by composites reinforced with lignocellulosic fibers, intended for armoring applications. An investigation was carried out regarding the characteristics of curaua (Ananas erectifolium) and carnauba (Copernicia prunifera) fibers, examining the average diameter, morphological and chemical analyses. The mechanical characterization of the composites was carried out using curaua and carnauba fibers in continuous and aligned distributions through manual production of polyester-fiber composites with 10, 20 and 30%v/v, through tensile, flexural and Charpy impact. From these results, laminated polyester composites were produced for the first time, using hybrid systems with layers of Aramid-Curaua, Aramid-Carnauba and Curaua-Carnauba fabrics, adopting the molding process by cold pressing. All proposed hybrid composites have 30%v/v of fibers and were produced in non-alternating configuration, being submitted to ballistic impact tests considering the level of protection and residual velocity. The ballistic results showed that the Curaua-Carnauba systems were perforated, unlike the Aramid-Curaua and Aramid-Carnauba systems, which were not pierced, which obtained a level I of ballistic protection. In addition, through the residual velocity results, it confirmed the need for fabrics, not blankets, to be used for ballistic applications of these composites. The results are a strong indication of the possible potential of similar hybrid composite solutions.
Acesso aberto (Open Access)
Estudo de viabiliade econômica do processo de pirólise e craqueamento termo-catalítico em escala piloto utilizando-se material ligno-celulósico, lipídico, de óleo de palma (elaeis guineensis, jacq) e resíduo da neutralização do óleo de palma
(Universidade Federal do Pará, 2022-12) AMARAL, Anderson Rocha; SANTOS, Marcelo Costa; http://lattes.cnpq.br/5640587707776287; MACHADO, Nélio Teixeira; http://lattes.cnpq.br/5698208558551065
In this work, it is accomplished a tecno-economic assessment of the production of bio-oil, coke and gas, via thermos-catalytic pyrolysis followed by distillation. The raw materials were: lipid-base material (residual fat/scum from fat retention box of the University Restaurant at the Federal University of Pará - UFPA), lignin-cellulosic material Açaí seed (Euterpe oleracea. Mart), palm oil and neutrilzing sludge palm oil. From the literature is made a review of the physic-chemical analysis of the raw materials, of the bio-oil and of chemical composition of the biofuels produced (biogasoline, bioquerosene, light-diesel and heavy-diesel). Are also presented the bio-oil yields for each experiment of pyrolysis and distillation and compared with the literature. The economic indicators demonstrated feasibility of the all projects, with exception with the use of açaí seeds. The indicators used to analysis the projects were: a) simple payback criterion, b) discounted payback, c) net present value (NPV), d) internal rate of return (IRR), and e) index of profitability (IP). The minimum fuel selling price (MFSP) obtained is this work for the biofuels was of 1.34 US$/L for all projects, with exception to the palm oil, which was 1,59 US$/L. The sensibility analysis demonstrated that the pyrolysis and distillation yields are the most important variables to affect the minimum fuel selling price (MFSP).
Acesso aberto (Open Access)
Evolução estrutural do hidro-carvão e cinética da decomposição da palha de milho no processamento hidrotérmico com H2O quente comprimida
(Universidade Federal do Pará, 2023-04-24) TERIBELE, Tiago; SANTOS, Marcelo Costa; http://lattes.cnpq.br/8380189608965320; MACHADO, Nélio Teixeira; http://lattes.cnpq.br/5698208558551065
In this work, the effect of reaction time and biomass-to-H2O ratio on the structural evolution of hydrochar and kinetic of by hydrothermal processing of corn Stover with hot compressed H2O, have been systematically investigated. The experiments were carried out at 250 °C, heating rate of 2.0 °C/min, biomass-to-H2O ratio of 1:10, and reaction times of 60, 120, and 240 minutes, and at 250 °C, 240 minutes, heating rate of 2.0 °C/min, and biomass-to-H2O water ratio of 1:10, 1:15, and 1:20, using a pilot scale stirred tank reactor of 5 gallon. The characterization of solid phase products performed by thermo-gravimetric analysis, scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction, and elemental analysis (C, N, H, S). The physical-chemistry properties of solid phase analyzed in terms of dry matter (DM), total organic content (TOC), and ash. The yields of solid and gas phases decrease linearly with decreasing biomass-to-H2O ratio, while that of liquid phases increases linearly. For constant biomass-to-H2O ratio, the yields of solid, liquid, and gaseous reaction products varied between 52.97 and 35.82% (wt.), 44.84 and 54.59% (wt.), and 2.19 and 9.58% (wt.), respectively. The yield of solids decreases exponentially by decreasing the reaction time, while the yields of liquid and gas phases increase exponentially. For constant biomass-to-H2O ratio, TG/DTG curves shows that reaction time of 60 minutes was not enough to carbonize corn Stover. For constant reaction time, TG/DTG curves shows that increasing the H2O-to-biomass ratio worse the carbonization of corn Stover. For constant biomass-to-H2O ratio, the SEM images show the main morphological structure of the corn Stover remains practically unchanged, while for constant reaction time, SEM images show that plant microstructure retains part of its original morphology, demonstrating that a decrease on biomass-to-H2O ratio worse the carbonization of corn Stover. For constant biomass-to-H2O ratio, the EDX analysis shows that the carbon content in hydrochar increases with reaction time, while for constant reaction time, the carbon content decreases with increasing biomass-to-H2O ratio. The kinetic of corn Stover degradation was correlated with a pseudo-first order exponential model, exhibiting a root-mean-square error (r2) of 0,996, demonstrating that degradation kinetics of corn Stover with hot compressed H2O, expressed as hydrochar formation, is well described by an exponential decay kinetics.
Acesso aberto (Open Access)
Métodos de obtenção e caracterização de biomembrana de quitosana e copaíba para potencial uso em feridas
(Universidade Federal do Pará, 2022-06-14) PARANHOS, Sheila Barbosa; PASSOS, Marcele Fonseca; http://lattes.cnpq.br/0588450144351187; https://orcid.org/0000-0002-5616-2127; CANDIDO, Verônica Scarpini; http://lattes.cnpq.br/8274665115727809; https://orcid.org/0000-0002-3926-0403
Health professionals deal directly with several complex situations in the care of sick people. Among these, there are skin wounds that can harm the patient's clinical condition, in addition to costly treatment for healing. Skin wounds require dressings to protect against pathogenic microorganisms and to accelerate the healing process. With the emergence of biomaterials available for use in wound treatment, chitosan has become an effective choice, easily found in a natural and renewable form with healing potential. The chitosan membrane presents ideal conditions in the treatment of wounds, such as absorption, protection, biocompatibility and antimicrobial potential. To increase its healing effects, natural oils have been incorporated into the polymer matrix, such as copaiba, which has a high anti-inflammatory action. In this context, the work aimed to obtain and characterize chitosan membranes by emulsion and nanoemulsion of copaiba oil to treat skin wounds. The chitosan membranes with oil addition by emulsion and nanoemulsion were synthesized by the solvent evaporation technique. They were evaluated by macroscopic analysis and characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, swelling percentage, humidity, contact angle. An in vitro assay of antibacterial activity against the bacterium S.aureus was carried out. The membranes had an apparently thin appearance, little malleability, relative opacity, continuous and good handling. He observed more porosity on the surfaces of membranes synthesized by nanoemulsion of copaiba oil, in addition to a more amorphous behavior. He noticed a better interaction between chitosan and oil constituents when the oil synthesis was prepared by nanoemulsion, resulting in improved stability of the material produced. The swelling percentages were higher in the MQCoN-0.1 (214±3.22%) compositions when immersed in water and the MQCoN-5.0 composition (220±6.83%) in the PBS solution. The wetter behavior was significant in membranes composed of 0.1% (0.80±1.37%) and 0.5% (3.00 ±0.79%) copaiba oil nanoemulsions. There was no great influence on the contact angle between syntheses and compositions. The chitosan membrane with 1.0% (v/v) of emulsified oil and the chitosan membrane with 0.5% (v/v) of nanoemulsified oil were the most hydrophilic membranes. All membranes were able to inhibit bacterial growth, except the chitosan membrane with 1.0%(v/v) oil emulsion. Materials obtained by nanoemulsion have ideal attributes for application in the use of skin wounds.
Acesso aberto (Open Access)
O Uso de polímeros reciclados na construção civil: uma proposta de habitação sustentável
(Universidade Federal do Pará, 2023-02-01) FERREIRA, Taiza Naiana da Silva; DIAS, Carmen Gilda Barroso Tavares; http://lattes.cnpq.br/2113791118142177
In recent decades, urban development has resulted in the unbalanced production of plastic materials as waste, waste that can be reused as raw material for a new production cycle. This work presents a proposal for sustainable housing with the use of floors, blocks for sealing with thermo acoustic blanket and sustainable tiles. For their preparation, rotational molding and compression molding equipment was assembled. Residues of polymers and natural fibers were used to make these constructive elements. The polymers used for the development of the floor were polystyrene (PS) disposable cups; ecological blocks were modeled and processed from post-consumer polypropylene (PP) and high-density polyethylene (HDPE) packaging; tiles were molded from discarded laminates; the floors became resistant to abrasion due to the presence of babassu fibers. The blocks provided acoustic comfort by including açaí fiber blankets, the walls were assembled using blocks and a commercial product for laying and overlapping. Housing as a model for recycling materials discarded in the environment will be able to generate proper disposal, providing income, increasing the life cycle of these materials, producing ecological products in civil construction and meeting at least four of the Organization's Sustainable Development Goals-SDGs of the United Nations.

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