https://repositorio.ufba.br/handle/ri/22482 2026-05-05T02:29:35Z https://repositorio.ufba.br/handle/ri/44434 Título: Avaliação das propriedades físico-mecânicas e reológicas de compósitos de cimento de fosfato de magnésio com adição de fibras de aço, de sisal (agave sisalana) e de pva Autor(es): Lima, Danilo Carvalho de Primeiro Orientador: Ribeiro, Daniel Véras Abstract: Magnesium phosphate cement (MPC) is an acid-base binder with superior physical mechanical properties compared to conventional hydraulic cements, yet it still presents many gaps, aiming at its development and wider application. This study evaluates the physical, mechanical, and rheological performance of MPC composites reinforced with PVA, sisal, and steel fibers in different proportions, aiming to reduce the brittleness and low deformability of the cementitious matrix. The MPC raw materials (calcined MgO, ammonium dihydrogen monophosphate - ADP, sodium tripolyphosphate – STP, and boric acid), sand, and steel (metallic), polymeric (PVA), and sisal (vegetable) fibers were characterized in terms of physical, chemical, and mineralogical aspects to optimize the formulation and allow evaluations of the composites in the fresh and hardened states. In the fresh state, setting time, pH, calorimetry, and rheological analysis tests were performed on the reference matrix and samples with different fiber contents. After molding and curing, the samples were subjected to phase formation analysis by XRD and thermogravimetry (TG/DTA), in addition to physical-mechanical analysis (specific mass, apparent porosity, capillary absorption, dimensional stability, axial compressive strength, and flexural tensile strength). The results showed that the addition of steel fibers to the CFM promoted significant gains in flexural tensile strength and compressive strength, with emphasis on the increase in toughness, evaluated by the I10 factor, indicating a more ductile post-cracking behavior and an efficient redistribution of stresses. While the addition of natural fibers to the composites resulted in a loss of mechanical performance, contributing to reduced strength values and increased variability in results, possibly due to high water absorption and low interfacial adhesion with the matrix, the chemical acetylation treatment showed promise in improving the mechanical properties of CFM composites with sisal fibers. The insertion of PVA fibers into the CFM matrix provided a modest improvement in mechanical strength compared to the reference matrix and superior performance to that of composites containing natural sisal fibers. Editora / Evento / Instituição: UNIVERSIDADE FEDERAL DA BAHIA Tipo: Dissertação 2026-03-03T00:00:00Z https://repositorio.ufba.br/handle/ri/44431 Título: Avaliação em massa de imóveis urbanos através de modelagem de regressão espacial Autor(es): Gonçalves, Waltério de Oliveira Primeiro Orientador: Alixandrini Junior, Mauro José Abstract: With the increasing demand for efficiency in municipal revenue collection, real estate appraisal has gained even more relevance due to the fundamental role of the Property and Territorial Urban Tax (IPTU). Since the implementation of Complementary Law No. 101 of May 4, 2000, known as the Fiscal Responsibility Law (LRF), municipalities have faced an urgent need for more robust methods to calculate the market value of properties, driven by the pursuit of tax equity. Detailed and precise planning is essential to ensure that the values assigned to properties fairly reflect their characteristics and location. This study modeled parameters for the appraisal of urban properties, promoting fair proportionality in the generation of Generic Value Maps (PVG). The research was conducted in Camaçari, a municipality in the Metropolitan Region of Salvador (BA), which has over 300,000 inhabitants and stands out as one of Brazil's main industrial hubs, hosting the Camaçari Industrial Pole. The study covered areas in the neighborhoods of Arembepe, Barra de Jacuípe, Boa Esperança, Genipabu, and Vale do Landirana, using a sample of 124 land plots for modeling and 12 for validation. The methodology compared the Ordinary Least Squares (OLS) regression with the global spatial model Conditional Auto Regressive (CAR) and the local Geographically Weighted Regression (GWR) model. The models were evaluated based on quality indicators such as the Akaike Information Criterion (AIC), Log Likelihood (LIK), coefficient of determination ($R^2$), and Root Mean Square Error (RMSE), in addition to specific metrics for mass appraisal, such as Median Ratio (Med R), Coefficient of Dispersion (COD), and Price Related Differential (PRD), according to the International Association of Assessing Officers (IAAO) criteria. The results indicated that GWR was able to significantly reduce spatial effects, outperforming the other models in most quality and performance criteria. The methodology was combined with Ordinary Kriging to generate unit value surfaces. The semivariogram adjusted to the Gaussian model allowed the kriging of predicted values, and the surface generated by the GWR predicted values achieved the lowest RMSE and better performance indicators, close to the limits recommended by the IAAO. It is concluded that GWR modeling was the most effective in representing spatial variations in real estate values in the studied area, and the proposed methodology for PVG generation demonstrated great potential for application by municipalities in the mass appraisal of urban properties, contributing to fairer and more precise tax collection, especially for taxes such as IPTU and the Real Estate Transfer Tax (ITBI). Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2025-03-28T00:00:00Z https://repositorio.ufba.br/handle/ri/44305 Título: Durabilidade química e biológica de fibras vegetais tratadas com nanopartículas de prata para uso como reforço de matrizes cimentícias. Autor(es): Alves da Silva Neto, Gilberto Primeiro Orientador: Lopes Lima, Paulo Roberto Abstract: Vegetal fibers have a low affinity to the high alkalinity of Portland cement matrices, in addition to presenting high dimensional instability in the presence of moisture. Besides, lignocellulosic fibers are subject to fungal biodeterioration, mainly during storage. Thus, treatments on the fibers and matrices are required to have a durable composite. Therefore, this work aims to propose a thermochemical treatment that generates fibers impregnated with silver nanoparticles (AgNP) to verify their influence on dimensional instability and fiber-matrix interaction, in addition to their chemical and biological durability. After treatment, the jute and sisal fibers were evaluated for their physical, thermal, morphological, and mechanical properties. The proposed AgNP impregnation method was satisfactory, with efficiency dependent on the AgNP concentration and fiber species. A change in the surface texture of the fibers was observed, becoming rougher, with better dimensional stability and reduced water absorption capacity of the modified fibers. It is believed that not only thermal cycles but also the low pH of the AgNP solution altered the microstructure of the fibers. The fibers treated in aqueous AgNP solution did not show significant changes in tensile strength or Young's modulus compared to natural fibers. Regarding fiber-matrix adhesion, evaluated by the pull-out jhtest, better performance was observed for hornificated fibers, due to the morphological modification of the surface; however, the adhesion strength of these fibers after treatment with AgNP did not show significant modification. When subjecting these fibers to alkaline attack, changes were observed in the thermograms with removal of hemicellulose, surface damage with defibrillation and, consequently, reduction in the mechanical performance of the tensile strength of these fibers, regardless of the treatment applied. On the other hand, when subjecting the fibers to fungal attack by direct contact, a superior performance of the fibers treated with AgNP was noted, evidenced by the little altered thermograms, absence of damage in the morphology, and maintenance of the tensile strength and Young's modulus. Thus, in general, the treatment of plant fibers with AgNP proved to be satisfactory for application in cementitious composites. Editora / Evento / Instituição: UNIVERSIDADE FEDERAL DA BAHIA Tipo: Tese 2025-06-03T00:00:00Z https://repositorio.ufba.br/handle/ri/44283 Título: Modelo para gerenciamento do processo de digitalização do licenciamento de obras na etapa de concessão dos alvarás para construção em municípios brasileiros Autor(es): Brito, Douglas Malheiro de Primeiro Orientador: Costa, Dayana Bastos Abstract: Municipalities around the world are seeking to digitalize the building permit process, especially the construction permit stage, to reduce processing times and increase the efficiency and automation of code checks. There is a growing interest in studies that develop tools that enable a greater understanding of how municipalities can gradually advance through the digitalization stages. However, the literature has indicated that these studies need to consider organizational and procedural aspects of digitalization, in addition to the technological aspect, allowing for an understanding, management, and control of a gradual transition from traditional processes. The objective of this study is to propose a model for managing the planning, implementation, and monitoring of the digitization process for building permits in medium-sized to large Brazilian municipalities. The research strategy adopted was Design Science Research (DSR), involving a longitudinal case study in the Brazilian municipality of Salvador, the conducting of two surveys, and the identification of pioneering digitalization initiatives in 22 countries to propose the model. The evaluation included conducting simulations of twelve possible digitalization scenarios and applying the model to the municipality of Belo Horizonte. The results obtained comprise a management model with an evolutionary roadmap, considering eight factors influencing the digitalization process, seven metrics for estimating and monitoring performance, as well as recommendations for implementation and supporting artifacts, according to the context, extension, and level of digitalization and automation intended by the municipality. The main theoretical contribution is associated with the model’s multiplicity of functions, whether through the representation of the planning, sequencing, implementation, monitoring, updating of municipal legislation and restarting of digitalization stages, or the managerial character of supporting decision-making by municipalities through its potential to sequence digitalization, simulate scenarios, estimate performance and evaluate the progress of maturity until the achievement of the intended levels of digitalization and automation.. As a practical contribution, the operationalization of the model in an application tool, along with documents containing recommendations and best practices, can assist municipalities in developing implementation strategies. Furthermore, the proposed metrics can guide decision-making by the professionals involved, from the initial planning and sequencing stages to monitoring performance and the benefits achieved. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Tese 2025-12-12T00:00:00Z