EECA - Escola de Engenharia Civil e Ambiental
URI Permanente desta comunidade
Navegar
Navegando EECA - Escola de Engenharia Civil e Ambiental por Por tipo de Acesso "Attribution-NonCommercial-NoDerivs 3.0 Brazil"
Agora exibindo 1 - 4 de 4
Resultados por página
Opções de Ordenação
Item Análise não linear de placas retangulares compostas de material viscoelástico(Universidade Federal de Goiás, 2020-06-19) Dias, Phablo Veríssimo Inácio; Soares, Renata Machado; http://lattes.cnpq.br/1938664529309726; Del Prado, Zenón José Guzmán Núñez; http://lattes.cnpq.br/7703344458057759; Del Prado, Zenón José Guzmán Núñez; Soares, Renata Machado; Silva, Frederico Martins Alves da; Orlando, DiegoBased on Kelvin-Voigt mechanical model, in this work the viscoelastic damping in nonlinear vibrations and dynamic instability of transversally and axially loaded rectangular plates is studied. Rectangular plates with initial geometric imperfections and with linear rotational springs at the edges are admitted in order to consider clamped boundary conditions. The non-linear Von-Kármán relations are used to describe the deformation relations of the plates and the system of non-linear dynamic equilibrium equations is found through the Hamilton principle by way of application of the Rayleigh-Ritz method, being solved later through of the fourth-order Runge-Kutta method. Initially, using the frequency-amplitude relations the influence of the viscoelasticity parameter on the plate’s non-linear mechanical behavior is investigated, observing that with the increase in the viscoelasticity parameter, the maximum amplitudes and non-linearity of the response decrease. The resonance curves, the post-critical path, the bifurcation diagrams, the attraction basins, the phase plans and the Poincaré maps were obtained for two different plates under distinct loading conditions. It is shown that, for all the amplitudes of the transverse loading studied, the plate presents periodic solutions of period 1T. When the plate is analyzed with higher levels of axial loading, this response may have periods of high order, and quasi-periodic and chaotic responses are also found. In all cases, a behavior of hardening of the plate is observed, however, in the study of effect of initial geometric imperfections, the response may become initially softened for high levels of imperfection. Finally, a nonlinear damping model is also used, which is compared with an equivalent viscous damping model.Item Estudo sobre o transporte de cobre em solo arenoso laterítico estabilizado com fosfogesso e bentonita(Universidade Federal de Goiás, 2020-06-29) Ferreira, Eduardo Silva; Silveira, Leonardo Ramos da; http://lattes.cnpq.br/4994189165685449; Mascarenha, Márcia Maria dos Anjos; http://lattes.cnpq.br/5184066802578105; Rezende , Lilian Ribeiro de; Mascarenha , Marcia Maria dos Anjos; Boscov , Maria Eugenia GimenezThe compacted soil barriers are currently one of the most used processes for building liners in landfills. Dimensioning these containment structures requires the knowledge of contaminant transport parameters in porous media, such as adsorption, which acts to delay the movement of the contaminant, and diffusion, a mechanism that dominates the contaminant transport process when one works with low permeability. Thus, the objective of this work was to experimentally obtain the Cu2+ retention capacity in a lateritic sandy soil stabilized with phosphogypsum and bentonite. For this, tests were performed on Soil (S) and lateritic sandy soil with 10% phosphogypsum (SF), lateritic sandy soil with 6% bentonite (SB6) and lateritic sandy soil with 10% phosphogypsum and 6% bentonite (SFB6), with Cu2+ concentrations varying between 0 and 800 mg/L. Chemical, physical and mineralogical characterization tests were performed for soil, SF, SB6 and SFB6 tests, indirect compatibility tests to evaluate the interaction between Cu2+ and the materials and batch test to obtain the adsorption capacity. The diffusion tests were carried out with the soil, SB6 and SFB6 compacted in the water ratio and maximum specific weight in the normal Proctor energy. The chemical, physical and mineralogical characterization tests demonstrated that the stabilization of the soil with bentonite reduced the pores of the macrostructure, but kept the characteristics of the soil intact. The phosphogypsum increased the availability of Ca2+ by raising the CTC of the materials up to 8.36 times in relation to the soil, however the Ca2+ made available was not available for ion exchange, in addition, the phosphogypsum acted in a way against the bentonite, increasing the diameters pores in certain PSD strips. The indirect compatibility analyzes show that Cu2+ acted in order to aggregate the particles of the soil and of the SB6 mixture, but showing itself compatible with the materials used. The results of batch tests showed that the stabilization causes an increase in the retention capacity by the materials, with the following removal order SB6> SFB6> SF> S, with stabilization with bentonite being more efficient than phosphogypsum. The diffusion cells constructed were efficient for carrying out tests with compacted soil. The use of stabilizers improved the ability to attenuate the diffusive transport of Cu2+, where the soil allowed a greater advance of Cu2+ with a lower reduction in concentration in the reservoir, SFB6 showed a reduction in the concentration of the reservoir close to the soil, however with less advances of concentrations in the liner and finally the SB6 showed a greater reduction in concentration in the reservoir and greater immobilization of the contaminant in the first layer compared to other materials. In this way, the adsorption and diffusion tests demonstrate that the use of stabilizers improved the ability to attenuate the transport of Cu2+, and it is recommended to use them in geoenvironmental works designed to retain Cu2+ ions.Item Seleção de tecnologias de tratamento de esgoto utilizando análise multicritério(Universidade Federal de Goiás, 2020-03-20) Freitas, Elaine Cristina Brás de; Teran, Francisco Javier Cuba; http://lattes.cnpq.br/3433455726987770; Teran, Francisco Javier Cuba; Cuba, Renata Medici Frayne; Scaratti, DirceuAmong the main causes of pollution of water bodies is the discharge of sewage without any type of treatment. To reduce this type of pollution, it is necessary to implement efficient sewage treatment systems, whether they are the responsibility of public service providers or the respective generators. The choice of sewage treatment technologies is a complex process, as they involve both quantitative and qualitative variables. Thus, to achieve the objective defined in this work, which is the selection of sewage treatment technologies using multicriteria analysis applicable in municipalities in the State of Goiás that do not have a sewage system, the Electre I method was defined, to select from among 37 sewage treatment technologies most used in Brazil, a set composed of the best technology options. For this, three scenarios were defined, and 16 criteria with technical, economic, social and environmental characteristics for scenario 1, 10 criteria for scenario 2 and 8 criteria for scenario 3. The application of the method was adequate for the selection of technologies sewage treatment. The selection for scenario 1 indicated a set consisting of 2 alternatives (anaerobic lagoon + optional lagoon + maturation pond and slow infiltration); for scenario 2 a set consisting of 5 alternatives (septic tanks, optional pond, optional aerated pond, slow infiltration and UASB reactor) and for scenario 3 a set with 3 alternatives (septic tanks, optional aerated pond and UASB reactor).Item Reaproveitamento de sabugo de milho para potencial remoção de formulação comercial de glifosato em fase aquosa pela técnica de adsorção(Universidade Federal de Goiás, 2020-03-30) Marcelino, Nayara Valéria Assis; Cuba, Renata Medici Frayne; http://lattes.cnpq.br/2178652705357657; Cuba, Renata Medici Frayne; Teran, Francisco Javier Cuba; Ostroski, Indianara ConceiçãoLike the chemical industries applied to agriculture and livestock, they develop several chemicals for use in the environment, including chemicals that can be used for endocrine disrupting activities. In this context, the use of the herbicide Glyphosate (GLF), which is among the four most used agrochemicals in Brazil (glyphosate and its salts; 2,4-D; Acephate; mineral oil) is the main used, soybean and sugar cane. The main source of exposure of glyphosate to living organisms is a water intake, since water and wastewater treatment systems are not able to remove or degrade by a complete series of synthetic organic compounds. In this situation, it is necessary to use complementary treatment methods, of which adsorption may be of technical and environmental interest, due to its efficiency and, mainly, in the versatility of raw materials used for the production of material adsorbent. Thus, the objective of this study was the reuse of corn maize through the production of biochar (BC) and activated carbon (CA), for potential removal of glyphosate herbicide (GLF) (commercial use) in aqueous medium using the technique of adsorption. The BC was subjected to only the carbonization step, while the CA was subjected to carbonization followed by chemical activation with H3PO4. The adsorbents were characterized by X-ray diffraction (DRX) and infrared analysis by Fourier transform (FTIR), adsorption and N2 desorption, scanning electron microscopy (SEM) and determination of the zero charge potential (pHPCZ). The effect of the initial pH and the adsorbent mass was also evaluated. The kinetic studies of adsorption were adjusted to the models of pseudo-first and pseudo-second order. The nature of the adsorption process was studied using the Langmuir and Freundlich isotherm models, and the thermodynamic parameters calculated for the temperatures of 23, 43 and 63 ° C. The acid treatment caused an increase in the surface area (7.48 m² / g BC to 34.126 m² / g CA) favoring the formation of mesopores and had little influence on the surface loads. The adsorption of GLF proved to be highly dependent on pH and both adsorbents reached their maximum adsorption capacity at neutral pH (7.0). Both adsorbents reached equilibrium in 60 min of testing, and in just 15 min the CA reaches 93% of its maximum adsorption capacity and the BC 68%, showing a better fit to the pseudo-second model. indicating a tendency for chemical adsorption. The equilibrium data obtained experimentally, for temperatures of 23, 43 and 63 ° C, showed a better fit to the Langmuir model for the BC indicating chemisorption, and Freundlich for the CA indicating Fisissorection. Chemical activation increased the maximum adsorption capacity (Langmuir qmax) from 1.08 mg g-1 to 1.51 mg g-1 The values of the thermodynamic constants revealed that the adsorption of GLF is endothermic in nature, favored with the increase in temperature (ΔH> 0), and endergonic (ΔG> 0), indicating that the adsorption process is not spontaneous.