Navegando por Assunto "Coating"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Comportamento de argamassas de revestimento quanto à retração, fissuração e mecanismo de descolamento em substratos de concreto
(Universidade Federal do Pará, 2013-10-22) LIRA, Mariana Domingues von Paumgartten; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
This research aims to evaluate the retraction, by the mortar superficial movement, occurrence of cracking and detachment of the mortar. Were choosed two types of substrate, one with a 30 Mpa resistance and other with 40 MPa resistance, also were used two types of mortar, one with additive and other lime based, two thicknesses of coating layer, from 15 mm and 30 mm, and was simulated the exposure condition that the region has.For this, tests were performed to characterize the mortar in the fresh state (consistency, water retention, air entrainment and mass density) and in the hardened state (compressive strength, tensile strength in bending, specific gravity, water absorption, voids and density). After preparation of the samples for evaluation, were taken the measures of superficial movement of the mortar for 28 days and the occurrence of cracks and detachment, as well as the verification of the bond strength of the coating and also the loss of water by evaporation of mortars. As a result of this research, it was observed that the variation of the resistance of the substrate analysis not showed a significant difference in the shrinkage, as well as the thickness of the layer to some series. It was also found that the type of mortar, or the material composition, has a direct influence on retraction. With regard to water loss by evaporation from the mortar, it can be seen that the additive achieved greater success in water retention materials. In the test of bond strength, was found that the most significant influence was in relation to the composition of the mortars and that they had values above the minimum allowed by regulatory norm.
Acesso aberto (Open Access)
Patologias em fachadas: análises de casos na Universidade Federal do Pará
(Universidade Federal do Pará, 2014-03-28) CARVALHO, Isabella Chaves; PICANÇO, Marcelo de Souza; http://lattes.cnpq.br/4535052395600357; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
The system of external cladding of the building acts as a protective layer and contributes to the proper aspect. The facade is subject to the action of agents of degradation as one of the most exposed areas of the building, with the presence of pathology becoming responsible for high repair costs. Research suggests as a general goal, assess conditions affecting building facades of higher education in the Federal University of Pará, guided by a theoretical basis (literature review) responsible for the first information on the subject. To such as research methodology, we sought to first do a physical survey of facades of 30 buildings in UFPA, identifying cadastral records in the main degradation mechanisms. Then, after quantify / qualify the anomalies present in the sample and point out the most critical building with key injuries and their causes, listed up to this, basic intervention measures in order to solve efficiently the problem caused by proposing a document that acts as technical support for inspection of facades generally. We also used the test to characterize samples in order to prove the origins of those damages which at first could not identify the cause. The results showed that the analyzed buildings have pathological damage of different nature and degree of complexity, ranging from the most complex requiring specific tests to discover their origin, even the most simple, with scheduled maintenance can be eliminated. We conclude that much of the damage happen by human negligence, but that even with an emphasis on quality of execution in facades, there is no way rule out failures or ignore the time of use and the actions of external factors lead to degradation Nature of the building. We conclude that much of the damage happen by human negligence, but that even with an emphasis on quality of execution in facades, there is no way to reject the hypothesis failures or ignore the time of use and the actions of external factors lead to natural degradation of the building. Therefore, to prevent the early onset of pathologies in facades, bringing its useful life and reducing extra costs, it is suggested, implementation procedures based on technical standards enforcement of them, following project criteria and presenting periodic inspections so that preventive measures are taken in apt time.
Acesso aberto (Open Access)
Recobrimento de pimenta-do-reino (piper nigrum l.), em leito de jorro, com suspensão polimérica de amido de mandioca, plasticizada com etanol
(Universidade Federal do Pará, 2024-12-13) QUEIROZ, Nian Iury Ferrão; REGO, José de Arimatéia Rodrigues do; http://lattes.cnpq.br/4163468898377462; HTTPS://ORCID.ORG/0000-0003-0891-6438; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; https://orcid.org/0000-0002-1461-7306
This study aimed to evaluate the black pepper coating technique using a fluidized bed, focusing on its applicability in the food industry. The research explored the optimization of operational parameters, such as suspension flow rate, temperature, and blower flow rate, using the response surface methodology within a Box-Behnken design. The goal was to improve the efficiency of the coating process, ensuring uniform distribution of the coating over the black pepper grains. This study investigated the fluid dynamic and physicochemical behavior of black pepper seeds coated with a cassava starch-based biofilm, applying the spouted bed process. The seeds were classified in group D of the Geldart classification, indicating good fluidization potential and excellent flowability, facilitating the coating process. The sphericity of the seeds (0,98) and their density (1,45 g/cm³) directly influenced their behavior in the bed, allowing minimal fluidization at a velocity of 38,32 cm/s and a pressure drop of 7,13 cmH2O. The molecular interaction between the starch and ethanol generated biofilms with flexibility and mechanical strength. However, ethanol's volatility requires control during the drying process to maintain the biofilm's quality. The spouted bed process proved efficient for coating application, and the desirability function analysis indicated that the established criteria were satisfactorily met. The results confirm the technical feasibility of applying biopolymer coatings to black pepper seeds, contributing to the development of biodegradable alternatives aligned with environmental demands