https://repositorio.ufpb.br/jspui/handle/tede/5433 PPGECAM Sat, 22 Aug 2026 15:17:59 GMT 2026-08-22T15:17:59Z https://repositorio.ufpb.br/jspui/handle/123456789/38539 Título: Concreto permeável contendo resíduos de caulim e metacaulim: propriedades físicas, hidráulicas, mecânicas e adsortivas Autor(es): Bezerra, Diego de Paiva Orientador: Nóbrega, Aline Figueirêdo da Abstract: The intensification of urban soil impermeabilization has aggravated problems related to drainage and stormwater quality, requiring construction techniques capable of simultaneously performing hydraulic, structural, and environmental functions. In this context, the concept of multifunctional performance of pervious concrete stands out, being associated with the ability to combine hydraulic permeability, mechanical strength, and adsorptive capacity within a single material. From this perspective, kaolin residues, both in the fine fraction (FKR) and coarse fraction (CKR), present potential for application in pervious concrete mixtures, since kaolin-based materials are recognized for their adsorptive capacity. In addition, it is estimated that, for every ton of processed kaolin, approximately 80% becomes waste. This scenario represents a significant environmental liability due to the occupation of large disposal areas and the environmental degradation associated with mining activities, causing impacts on soils and adjacent water bodies. Given this context, this study evaluated the multifunctional performance of pervious concretes containing metakaolin, FKR, and CKR through an integrated experimental approach, including mechanical, hydraulic, and adsorption analyses of metallic ions (Al³⁺ and Fe²⁺) present in simulated contaminated stormwater. Initially, the chemical, mineralogical, physical, and morphological characterization of the materials was performed. Subsequently, the study was developed based on a preliminary analysis of cement pastes containing metakaolin replacements and additions (10% and 20%) relative to cement mass. The cement pastes with the best mechanical performance were later investigated in reference pervious concrete mixtures composed of natural aggregate and 10% and 20% metakaolin replacements relative to cement mass. Thereafter, concrete mixtures containing 10% metakaolin replacement relative to cement mass and additions of FKR and CKR at contents of 10%, 20%, 30%, and 40% relative to natural aggregate mass were analyzed. The pervious concretes were evaluated in both fresh and hardened states. Physical characterization included void ratio tests, two-dimensional image analysis obtained through Python programming, three-dimensional analysis using X-ray micro-computed tomography (micro-CT), texture analysis, and permeability tests. Mechanical properties were determined through compressive strength, flexural tensile strength, and abrasion mass loss tests. Additionally, durability against carbonation was evaluated. To integrate the different investigated properties, a multicriteria analysis based on dimensionless normalization was employed, allowing the identification of mixtures FKR10 and CKR10 as those presenting the best overall performance by balancing permeability, mechanical strength, and adsorptive capacity. The results demonstrated that additions of 10% FKR and CKR promoted moderate refinement of the paste–aggregate matrix, increased mechanical strength, and maintained permeability at adequate levels for pavements subjected to light traffic loads. In contrast, higher CKR contents (30% and 40%) resulted in mixtures with greater internal heterogeneity, less cohesive interfaces, and higher abrasion mass loss. The mixtures containing residues exhibited significant adsorptive performance during the initial hours of testing (First Flush), with Al³⁺ and Fe²⁺ removal efficiencies ranging from 25% to 48%. Therefore, based on the obtained results, it was possible to highlight that 10% contents of FKR and CKR may be considered the most technically viable for application in pervious concrete. Thus, the use of these residues may contribute to the circular economy, constituting a technically feasible and sustainable solution. Editor: Universidade Federal da Paraíba Tipo: Tese Fri, 26 Jun 2026 00:00:00 GMT https://repositorio.ufpb.br/jspui/handle/123456789/38539 2026-06-26T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38244 Título: Modelagem da evapotranspiração usando balanço de energia e imagens de aeronaves remotamente pilotadas Autor(es): Oliveira Júnior, Marcos Elias de Orientador: Melo, Davi de Carvalho Diniz Abstract: Evapotranspiration (ET) encompasses both soil water evaporation and plant transpiration and is a key process in maintaining the water and energy balance at the Earth's surface. It is divided into three components: soil evaporation, canopy transpiration, and interception of water retained by the canopy. The Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model is widely used for ET estimation; however, it does not include a robust method for integrating thermal data obtained by UAVs. This study aims to map ET using meteorological data and aerial images acquired by UAVs in a sugarcane cultivation area in the northern coastal region of Paraíba, Northeast Brazil. Additionally, it proposes to evaluate how the QGIS plugin QWaterModel can be integrated into models such as PT- JPL to improve the accuracy of evapotranspiration estimates. To achieve this, a performance analysis was conducted comparing the ET simulated by the models (QWater and PT-JPL) with observed ET values from a flux tower installed in a sugarcane field in the coastal region of Paraíba between October 2022 and August 2023. By combining PT- JPL with QWaterModel, this study seeks to enhance ET estimation accuracy, particularly in an agricultural context such as a sugarcane field. Editor: Universidade Federal da Paraíba Tipo: Dissertação Mon, 30 Sep 2024 00:00:00 GMT https://repositorio.ufpb.br/jspui/handle/123456789/38244 2024-09-30T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38099 Título: Estudo analítico-numérico de placas submetidas a ações pontuais e distribuídas em linha Autor(es): Siqueira, Ana Clara Ferreira Orientador: Mendonça, Ângelo Vieira Abstract: This work aims to discuss aspects of obtaining analytical and numerical solutions for plate problems, with or without elastic foundation support, subjected to point loads and/or line-distributed loads, using Kirchhoff and Mindlin plate theories. The analytical solutions for these problems were derived by manipulating the Dirac delta function (δ) for concentrated loads and the Heaviside function (H) for line distributions. Additionally, the strategies for obtaining the analytical solutions were based on the Levy and Navier methods. To enable numerical solutions for the plate problems, stiffness matrices associated with Winkler and Pasternak foundations were derived through mathematical manipulations compatible with the finite element formulations of DKT (Discrete Kirchhoff Triangle) and DST (Discrete Shear Triangle) elements, combined with linear or pseudo-consistent interpolations of transverse displacements within the element domain. Several analyzes were carried out involving different properties, boundary conditions and loading, the results of which were validated with analytical and/or numerical responses Editor: Universidade Federal da Paraíba Tipo: Dissertação Thu, 31 Jul 2025 00:00:00 GMT https://repositorio.ufpb.br/jspui/handle/123456789/38099 2025-07-31T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38097 Título: Análise dinâmica de placas duplas e delgadas pelo método dos elementos de contorno Autor(es): Rodrigues, Moab Bezerra Orientador: Mendonça, Ângelo Vieira Abstract: Plates are structural elements widely used in engineering applications, appearing in fields such as Civil Engineering, Mechanical Engineering, and Aerospace Engineering. Double- plate systems, in particular, are found in sandwich structures, nanometric structures, and highway and railway pavements, the latter two often being subjected to dynamic loading conditions. Accurate analysis of these systems is essential, especially when their interaction with elastic foundations is considered. Although analytical solutions are important, they are frequently restricted to simple geometries and boundary conditions, which limits their applicability. In this context, the primary objective of this work is to develop numerical solutions, using the Boundary Element Method (BEM), for thin double-plate systems connected by a Winkler elastic foundation under steady-state dynamic conditions. In addition, secondary discussions are extended to isolated single plates or single plates supported by a Winkler elastic foundation. The construction and validation of the numerical solutions presented in this study follow these steps: initially, the differential equations of motion defined in the continuous medium (plate) are transformed into equivalent integral equations valid over the domain and/or boundary of the plate through the application of the weighted residual method (where the equations of motion are weighted by fundamental solutions). A key contribution of this work is the original derivation of the fundamental solutions for the dynamic problem of double plates, which were previously unavailable in the literature. The discrete solution of the dynamic plate problem is obtained by discretizing the boundary into linear isoparametric boundary elements. After evaluating the corresponding integrals, an algebraic system is assembled. Finally, once the boundary conditions are imposed, the dynamic responses can be determined. Several examples using the BEM solution are presented and validated against analytical and/or numerical solutions, yielding relative errors lower than 1% for a discretization with 32 straight elements in rectangular plates and 8 curved (arc) elements in circular plates, implying on consistence of BEM solution showed. Editor: Universidade Federal da Paraíba Tipo: Dissertação Fri, 27 Mar 2026 00:00:00 GMT https://repositorio.ufpb.br/jspui/handle/123456789/38097 2026-03-27T00:00:00Z