Navegando por Assunto "Sensitivity"

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Acesso aberto (Open Access)
Análise comparativa das sensibilidades obtidas com o vane test e o mini vane em um depósito sedimentar na foz do rio Amazonas
(Universidade Federal do Pará, 2022-11-22) VIEIRA FILHO, Arudá Gomes; TEIXEIRA, Marcelo Rassy; http://lattes.cnpq.br/8912916360456192
The reed test has been used in field research for the elaboration of geotechnical projects and in the management of non-clay sedimentary deposits, due to the fact that it provides data such as undrained shear strength (Su) and sensitivity (St). The same results are obtained in the test with the laboratory straw (mini vane), but for that, it is necessary to extract samples considered undisturbed, which, in this research, were recommended by the ABNT NBR 9820 standard. vane shear test with the laboratory vane test, also called Mini Vane. The location of this analysis is in a port region located at the mouth of the Amazon River, in a natural sedimentary deposit, which presented two slope disruptions with characteristics peculiar to soils with high sensitivity. Landslides on slopes are usually predictable from a geotechnical point of view, however in this researched region the soil presented rapid landslides on the slope, showing signs of a soil with high sensitivity. The research pointed out that the laboratory vane test (mini vane) presented a greater (St) when correlated with the (St) of the simple compression tests, giving greater clarity that there is a very soft clayey soil with a depth between 30 and 40 meters, typical of a ground lens that performed with high sensitivity. Comparisons between the reed tests showed consistency in the results, even in soil layers with different consistency indices than the initial layers, the validations of the reed tests were validated with the tests performed by simple compression. Finally, the soil of this deposit had its sensitivity identified in the field straw test. The same identification was confirmed on the Mini Vane. However, at depths greater than the field vane. In this way, the tests carried out by the Vane Shear Test (VST) in situ were primordial in the identification of the sensitivity, having its confirmation with the laboratory reed test (Mini Vane).
Acesso aberto (Open Access)
Eletroquímica coloidal e sua relação com a sensibilidade de um solo argiloso na foz do rio Amazonas
(Universidade Federal do Pará, 2023-06-29) SOUSA, Flaviany Luise Nogueira de; TEIXEIRA, Marcelo Rassy; http://lattes.cnpq.br/8912916360456192
Clays have always played an important role in the history of civilizations, mainly because they are a mineral resource with varied technological applications. Among the several existing types, sensitive clays (quick clays), for example, are very complex soft soils that are considered real challenges for engineers due to the difficulty in obtaining their geotechnical parameters. In this sense, the aim of the present study was to analyze the sensitivity of a clay soil found in a region of the city of Santana, in the state of Amapá, Brazil. To this end, physical and chemical tests were carried out, including the SPT (Standard Penetration Test), X-Ray Diffraction (XRD), Zeta Potential (ζ), pH, Cation Exchange Capacity (CEC), as well as resistance assays (Vane Test and Fall Cone Test – FCT). The analyzed area is located in the Macapá Fluvio-marine Plain, which is composed of sediments that were deposited both by rivers and by the sea as a result of the region’s proximity to the mouth of the Amazon River. The geological profile obtained through geotechnical investigation indicated that the soil is constituted of mottled sandy-clay sediments, sandy-silty sediments with plant remains, and sandy- silty sediments with pebbles. As for the mineralogy of the samples, they were essentially composed of quartz and three clay minerals: kaolinite, mica/illite, and chlorite. Regarding sensitivity, all samples were classified as quick clays, with medium or high amounts of organic matter (O.M.); greater organic matter content was associated with increased sensitivity. In addition, it was understood that the intensity of clay sensitivity was higher with the increase in monovalent cations and the decrease in divalent cations such as Ca2+ and Mg2+, which must have been removed by the O.M. The soil pH reading ranged from high to very high acidity, an expected classification due to the increase in H+ concentration due to the O.M. All samples showed similar ζ values, with the lowest being 31.3 mV and 33.2 mV, which are still considered high, indicating that the soil colloids repel each other, forming a dispersed structure. Our results were consistent with similar reports in the literature; however, regionalized studies are necessary for a better understanding of the local peculiarities capable of influencing the profile of this soil.
Acesso aberto (Open Access)
Formas sociais, comunicação e tipificações do afeto numa torcida de futebol
(Universidade de São Paulo, 2020-08) FREITAS, Aline Meriane do Carmo de; CASTRO, Fábio Fonseca de
The article presents the results of an ethnography of the communication processes present in a soccer crowd, the barra brava Camisa 33, from Clube do Remo, in Belém-PA. Based on a proposition of dialogue between Anthropology and Communication, we sought to understand the intersubjective processes (Schutz, 1978, 2012) expressed by the affections and sensibilities experienced by the fans and shown in social forms (Simmel, 1999, 2006). We sought to carry out an analysis of the sociocultural communicative processes in order to understand the social construction of sensibilities and the production of sensitive meanings that involve team fans.
Acesso aberto (Open Access)
O meio-tom do sensível: criação, crítica e relações artísticas na pintura de Manoel Santiago (1920-1938)
(Universidade Federal do Pará, 2023-12-07) SILVA NETO, João Augusto da; FIGUEIREDO, Aldrin Moura de; http://lattes.cnpq.br/4671233730699231
The thesis discusses the art of the Amazonian painter Manoel Santiago and the artistic criticism of his works. The intended approach is directly linked to the theoretical methodological developments regarding the experiences of critics and artists, as well as their different demands, appropriations and understandings about art. In these terms, an analysis is made of the conditions of Santiago’s artistic creation based on his understanding of art and his social and artistic interactions during his performanc e in Rio de Janeiro between the 1920s and 1938. Throughout his artistic journey, Manoel Santiago shaped perceptions of himself, establishing a certain artistic individuality. In light of this, I emphasize the position that the painter assumed in the artistic scene, highlighting his choices and artistic practices as deliberate strategies to assert himself as an artist, enticing an appreciation for his paintings. Several critiques published in newspapers, books, and magazines are scrutinized with the aim of comprehending the painter's interactions and the perception of his works, with a focus on the relationship between sensitivity and the utilization of color . The thesis is defended that Santiago's idea of art and the process of artistic creation developed from interests and relationships within the worlds of art, in which both the painter himself and critics collaborated to build a certain image and artistic reputation.
Acesso aberto (Open Access)
Sensor quimiorresistor baseado em nanotubos de carbono para detecção de éter-amina
(Universidade Federal do Pará, 2025-06-25) FERREIRA, Débora Ely Medeiros; REIS, Marcos Allan Leite dos; http://lattes.cnpq.br/8252507933374637; HTTPS://ORCID.ORG/0000-0003-2226-2653; CORREA PABÓN, Rosa Elvira; http://lattes.cnpq.br/1410157252579591; https://orcid.org/0000-0002-0635-9095
The development of nanostructured sensors has become highly relevant for the detection of chemical and biological substances, as they require small concentrations and offer easy handling. In the context of detecting and reusing flocculants in iron ore flotation, Buckypapers (BPs) based on functionalized Multi-Walled Carbon Nanotubes (MWCNTs) were employed to serve as sensing elements in the investigation of samples containing deionized water (DW), ether-amine (EA), and salts (AlCl₃, FeO₄·7H₂O, CaCl₂·2H₂O, MgCl₂·6H₂O) at different pH levels. Morphological characterization of the BPs using Scanning Electron Microscopy revealed an aggregated organization of carbon nanotubes (CNTs), which appeared randomly distributed on the phenolic surface. Through chemoresistive testing, electrical resistance measurements over time (R × t) were obtained. The results, based on the sensor response (as a percentage increase) over time (seconds) for three cycles—each with 0.1 μL of the solutions prepared from DW, EA, sodium hydroxide (NaOH), and salts—showed that the sensor was able to distinguish between the solutions and their pH differences. It exhibited specific response (%), response time (s), and recovery time (s) for each solution tested. A notable increase in sensor response was observed with rising pH, with the solution containing 30 ppm EA + salts (pH 9.63) reaching an average response of 20.14%, an average response time of 188.60 s, and an average recovery time of 154.91 s, indicating that the sensor is more sensitive in alkaline environments. Vibrational analysis by Raman spectroscopy revealed sub-bands around the D band resulting from the chemical functionalization and solubilization processes of the MWCNTs, as well as sub-bands near the G band associated with vibrations of the inner and outer nanotube walls. For samples containing EA and salts, the results indicated charge transfer between the ether-amine and the outer layers of the CNTs in the BP. The presence of metallic salts influenced the G band profile, altering electron density and causing local distortions. Principal Component Analysis (PCA) showed that the distribution of scores could distinguish the 30 ppm EA samples with higher pH (9.76 and 10.70) and 30 ppm EA + salts (pH 9.63) from the NaOH samples (pH 9.80 and 10.74) and salt-only samples (pH 4.73 and 9.77), indicating the system's detection and differentiation capability toward ether-amine, NaOH, and salts. Thus, the nanostructured sensor demonstrated relevant results for EA detection and potential application in the industry to recover unutilized EA.
Acesso aberto (Open Access)
O som das marcantes: conexões sensíveis existentes entre a música brega paraense e seus ouvintes
(Universidade Federal do Pará, 2021-11-17) COSTEIRA, Igor Blendon de Souza; CASTRO, Fábio Fonseca de; http://lattes.cnpq.br/5700042332015787
This research paper aims to study the cultural and sensible universe of brega musicality in Pará State. It seeks to thematize and reflect on the sensible experience resulting from the relationship between this musical style and people who experience it in their daily lives. In general, brega music presents in its compositions messages that involve people's daily life issues and that arouse nostalgic sense of belonging and personal and cultural identification. The research is developed based on the interactive content extracted from a specific brega music channel on YouTube, on the basis of the formation and analysis of typified categories, using the typification methods by Alfred Schutz (1979). In order to build a theoretical reflection, the concepts of Heideggerian thought of everydayness, banality, Alfred Schutz's phenomenological perspective of Culture and Castro's semiotical blues (2015), will be phenomenological applications that will permeate to consolidate the understanding of this research. Therefore, a sensible, longing and intersubjective aspect was perceived in the temporal and nostalgic peculiarity of brega music from Pará State, which is present in the social fabric and in the popular imagination and guarantees the entry, passage and remaining of brega rhythm in Amazonian culture.