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School notebooks in the training of a normal school teacher: a historical-educational analysis of mathematical knowledge at Santa Joana D’Arc School (Rio Grande city, RS - 1938 and 1939)
No full textThe dissertation, situated within the fields of the History of Education and
Mathematics, develops a descriptive and analytical study of four school notebooks
in order to understand how the teaching of mathematics and didactics was
organized in the normal course at Santa Joana D’Arc School between 1938 and
1939. The notebooks reveal the possibility of understanding the analytical category
"object of school culture," highlighting the importance attributed to this artifact.
Therefore, as main theoretical concepts, we privileged the contributions of Ana
Chrystina Venancio Mignot (2008) and Antonio Viñao Frago (2008), as well as
other authors who discuss this theme. Through the analysis of the notebooks filled
out by the normal school student and the clues recorded within them, it was
possible to approach a past school culture and thus contribute to the History of
Education. The school notebooks analyzed in this study were filled out during the
training of Suelly Espindola while attending the Normal Course at Santa Joana
D’Arc School. Analyzing this set of notebooks highlights their remarkable
organization. The first notebook provides a comprehensive overview of the Pedagogy
field, containing explanations related to methods and strategies recommended for the
development and execution of lesson plans. The second notebook analyzed covers the
subjects of Arithmetic, Reading, Language, and Universal History, with detailed lesson
plans. It also includes the use of the book "Queres Ler" in Reading and Language classes.
The third notebook contains lesson plans for the subjects of Language, Reading, Morality,
Geography, Basic Concepts, Manual Work, Natural History, History, Gymnastics, and
Arithmetic. The arithmetic lesson plans followed stages of goal setting, concretization, oral
application, written application, and abstraction. The fourth notebook addresses the
methodology of various disciplines, highlighting concerns with the choice of the method to
be used. Thus, we analyzed the books that were aligned with the prioritized teaching
method, sharing the same pedagogical objective. Accordingly, the book used for reading—
"Primeiro Livro Queres Ler?", It followed the principles of the intuitive method, while the
books used in the mathematics discipline, Aritmética na “Escola Nova” and Arithmetica:
Curso Preparatório e Elementar, indicate that they were used as supplements and tools
for deepening the study of students' psychological types. Mathematics classes were
planned to integrate visual resources with approaches that stimulated students' critical
thinking. Thus, it can be concluded that the teaching of Mathematics at Santa Joana D’Arc
School met the educational demands of the time.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESA dissertação, inserida no campo da História da Educação (e) Matemática, desenvolve
um estudo descritivo e analítico de quatro cadernos escolares a fim de perceber como
foi organizado o ensino da matemática e da didática no curso normal da Escola Santa
Joana D’Arc entre os anos de 1938 e 1939. Identifica-se nos cadernos escolares a
possibilidade de entendimento da categoria analítica “objeto da cultura escolar”,
apresentando a importância atribuída a esse artefato. Sendo assim, como principais
conceitos teóricos privilegiamos os aportes teóricos de Ana Chrystina Venancio
Mignot (2008) e de Antonio Viñao Frago (2008), bem como de autores que discutem
essa temática. Por meio da análise dos cadernos preenchidos pela normalista e por
pistas neles registradas foi possível a aproximação com uma cultura escolar do
passado, e assim contribuir para a História da Educação. Os cadernos escolares
analisados neste estudo foram preenchidos no decorrer da formação da normalista
Suelly Espindola durante a realização do Curso Normal na Escola Santa Joana D’Arc.
Ao analisar este conjunto de cadernos, evidencia-se sua notável organização. O
primeiro caderno apresenta uma visão abrangente da área de Pedagogia, nele
contem explicações referente a métodos e estratégias recomendadas para a
elaboração e execução dos planos de aula. O segundo caderno analisado abrange
as disciplinas de Aritmética, Leitura, Linguagem e História Universal, contendo planos
de aula detalhados. Além do uso do livro Queres Ler nas disciplinas de Leitura e
Linguagem. O terceiro caderno contem planos de aula das disciplinas de Linguagem,
Leitura, Moral, Geografia, Noção Comum, Trabalho Manual, História Natural, História,
Ginastica e Aritmética. Os planos de aula de aritmética, seguiram as etapas de
objetivação, concretização, aplicação oral, escrita e abstrata. O quarto caderno,
aborda a metodologia de diversas disciplinas, destacando a preocupação com a
escolha do método a ser utilizado. Dessa forma, analisamos os livros que estavam
alinhados ao método de ensino priorizado, compartilhando o mesmo objetivo
pedagógico. Sendo assim, o livro utilizado para leitura, primeiro Livro Queres ler?,
seguia os princípios do método intuitivo, enquanto os livros utilizados na disciplina de
matemática, Aritmética na “Escola Nova” e Arithmetica curso preparatório e
Elementar, indicam terem sido utilizados como complementos e instrumentos de
aprofundamento no estudo dos tipos psicológicos dos alunos. As aulas de Matemática
eram planejadas de maneira a integrar recursos visuais com abordagens que
estimulassem o pensamento crítico dos alunos. Dessa forma, conclui-se que o ensino
de Matemática na Escola Santa Joana D’Arc, atendia às exigências educacionais da
época
Geological viability and nutrient availability of andesitic basalt rock powder as a soil remineralizer
No full textBrazilian soils are prone to a gradual decline in fertility due to intensive agricultural activity combined with the natural process of weathering. However, the use of conventional fertilizers results in a series of negative environmental impacts and limited access for smallholder farmers, as these products are typically imported. Over the past two decades, the development and improvement of techniques aimed at meeting crop nutritional needs with lower environmental impact have intensified significantly. Soil remineralization consists of supplying macro- and micronutrients through the addition of ground rock from specific lithologies. Law No. 12,890/2013 marked a milestone in the dissemination of this technique in Brazil by including remineralizers in the category of agricultural inputs. This law was later complemented by Normative Instruction No. 5/2016 from the Ministry of Agriculture, Livestock, and Supply, which established the technical criteria required for a rock to be commercialized as a soil remineralizer. The present study aimed to assess the geological viability and efficiency of ground andesitic basalt, occurring in southern Brazil, for use as a soil remineralizer. The methodology included mineralogical and geochemical characterizations, along with a leaching test to evaluate nutrient availability. Geochemical analysis showed that the lithology contains more than 15% of total base-forming oxides (K₂O, MgO, and CaO), with K₂O exceeding 1%, and lacks significant concentrations of potentially toxic elements (As, Cd, Hg, and Pb), thus complying with current legislation. Likewise, the leaching test using a 2% citric acid solution demonstrated the release of 36.25 mg/L of Ca, 24.95 mg/L of Mg, and 12.06 mg/L of K, confirming the nutrient availability under simulated acidic soil conditions. These findings confirm the geological viability of this lithology for use as a soil remineralizer. However, further field studies are recommended, as the current results are based exclusively on laboratory-scale experiments
How COVID-19 pandemic impacted students’ and staff ’s physical activity at a Brazilian University?
No full textIntroduction: Physical activity and its positive effects on coronavirus have been extensively discussed in the literature. However, there is still a lack of evidence on the effects of the coronavirus pandemic on the health-related behaviors of the Brazilian university community. Objective: To describe physical activity practice during the coronavirus pandemic among students and staff of a southern Brazilian university, as well as its association with sociodemographic characteristics. Methods: This self-administered web-based cross-sectional study was carried out among a southern Brazilian community. The main outcome of this study was leisure time physical activity before and during the coronavirus pandemic. Results: Considering only leisure-time, 21% and 24% of the students and staff, respectively, reported achieving physical activity recommendations (≥150 minutes per week). There was a decline of more than 15 percentage points in physical activity practice comparing to pre and during the pandemic, and those following the protocols of staying at home presented lower levels of leisure-time physical activity. Physical activity practice was mainly performed at home and without any professional help. Conclusion: Leisure-time physical activity prevalence during the pandemic was relatively low (compared with Brazilian population) among students and staff, and participants who followed the staying at home protocols presented lower levels of physical activity
Influence of temperature on the reproductive aspects of olive tree (Olea europaea L.) in the southern region of Rio Grande do Sul
No full textThe main objective of this work was to investigate the phenological aspects and thermal requirements of olive cultivars in the Southern Region of Brazil, as well as to evaluate the effects of temperature on stigma receptivity, pollen germination, and pollen tube growth. Additionally, it aimed to verify whether the application of boron at different concentrations could mitigate the effects of temperature on the latter two processes. The first article refers to the phenological characterization of the main olive cultivars in the southern region of Rio Grande do Sul between 2015 and 2024, relating the phenological stages to local thermal conditions. The base temperature (Tb) and accumulated thermal sum (STa) were determined for each stage. The cultivars Arbequina and Koroneiki showed lower Tb values and longer phenological cycles, while Picual required a higher Tb, accumulated more STa, and completed its cycle in less time. The second article evaluated the thermal requirements of four olive cultivars (Arbequina, Koroneiki, Picual, and Arbosana) between 2015 and 2024, focusing on the bud break and flowering stages. Chill hours (CH), chill units (CU), and accumulated thermal sum (STa) were determined. Results showed that chill accumulation ranged from 136 to 419 CH, while STa for bud break and flowering ranged from 61.50 to 242.80°C·day⁻¹. Arbequina and Koroneiki required less chilling and presented higher STa, whereas Picual demanded more chilling and lower STa. Mild winters anticipated phenological events, and insufficient chilling compromised floral synchrony. The study reinforces the importance of proper cultivar choice and thermal management to maintain productivity in subtropical regions. The third article assessed the effects of temperature (18 °C and 28 °C) and stigma exposure time (24, 48, 72, and 96 hours) on stigma receptivity in olive cultivars (Arbequina, Koroneiki, and Picual), analyzing pollen adhesion, germination, and pollen tube penetration. Conducted under controlled conditions in Southern Brazil (2023–2024), results indicated that ‘Picual’ showed greater stability and reproductive performance. At 28 °C, stigma receptivity was prolonged, and pollen germination increased. ‘Koroneiki’ and ‘Arbequina’ showed greater thermal sensitivity. These data highlight the importance of thermal control to optimize olive fruit set. For the fourth article, in vitro effects of different temperatures (12°C, 22°C, 25°C, and 12–22°C alternation) and boron concentrations (0, 100, 150, 200, 250, and 300 mg·L⁻¹) on pollen germination and pollen tube growth of the olive cultivars Arbequina and Manzanilla were evaluated. Pollen germination and pollen tube growth in olive trees vary according to temperature and boron concentrations. ‘Manzanilla’ tolerates low temperatures and requires higher boron levels, while ‘Arbequina’ performs better at higher temperatures and moderate boron concentrations. Doses above 200 mg·L⁻¹ are toxic, requiring cultivar-specific management.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESDiante da importância da olivicultura no Rio Grande do Sul, responsável por aproximadamente 60% da produção nacional, este estudo teve como objetivo determinar os aspectos fenológicos e as exigências térmicas de cultivares de oliveira na Região Sul do Rio Grande do Sul, bem como avaliar os efeitos da temperatura na receptividade estigmática, na germinação do pólen e no crescimento do tubo polínico. Buscou-se, ainda, analisar a aplicação de boro, em diferentes concentrações, para mitigar os efeitos da temperatura sobre esses dois últimos processos. A tese compõem-se de quatro artigos, sendo o primeiro a caracterização fenológica das principais cultivares de oliveira em Dom Pedrito (RS), entre 2015 e 2024, relacionando aos estádios fenológicos e as condições térmicas locais. Foram determinadas a temperatura base inferior (Tb) e a soma térmica acumulada (STa) para cada estádio. Os principais resultados neste artigo foram que as cultivares Arbequina e Koroneiki apresentaram menores valores de Tb e ciclos fenológicos mais longos, enquanto Picual exigiu maior Tb, maior soma térmica acumulada (STa), e completou seu ciclo em menor tempo. No segundo artigo avaliou-se as exigências térmicas de quatro cultivares de oliveira (Arbequina, Koroneiki, Picual e Arbosana) no período de 2015 a 2024, com base nos estádios de brotação e floração. Foram determinadas as horas de frio (HF), unidades de frio (UF) e soma térmica acumulada. A partir dos resultados verificou-se que o acúmulo de frio variou entre 136 e 419 HF, enquanto a STa para a brotação e floração variou entre 61,50 e 242,80°C.dia-1. Arbequina e Koroneiki exigiram menos frio e apresentaram maior STa, já ´Picual´ demandou mais frio e menor STa. Invernos amenos anteciparam os eventos fenológicos, e a insuficiência de frio comprometeu a sincronia floral. O estudo reforça a importância da escolha adequada de cultivares e do manejo térmico para manter a produtividade em regiões subtropicais. No artigo três, avaliou- se os efeitos da temperatura (18 °C e 28 °C) e do tempo de exposição dos estigmas (24; 48; 72 e 96h) sobre a receptividade estigmática em cultivares de oliveira (Arbequina, Koroneiki e Picual), analisando a aderência, germinação do pólen e penetração dos tubos polínicos, realizado sob condições controladas na região Sul do Brasil (2023–2024). Os resultados indicaram que ‘Picual’ apresentou maior estabilidade e desempenho reprodutivo. A 28 °C, observou-se prolongamento da receptividade e maior germinação do pólen. ‘Koroneiki’ e ‘Arbequina’ mostraram maior sensibilidade térmica. Para o artigo quatro, foi avaliado, in vitro, os efeitos de diferentes temperaturas (12°C, 22°C, 25°C e 12-22°C) e concentrações de boro (0; 100; 150; 200; 250 e 300 mg·L⁻¹) na germinação do pólen e crescimento do tubo polínico das cultivares de oliveira Arbequina e Manzanilla. A germinação do pólen e o crescimento do tubo polínico em oliveiras variam conforme temperatura e concentrações de boro. ‘Manzanilla’ tolera baixas temperaturas e exige maiores concentrações; ‘Arbequina’ responde melhor a altas temperaturas e a concentrações moderadas. Doses acima de 200 mg·L⁻¹ são tóxicas, exigindo manejo específico por cultivar
Ionic Substitution of Sodium for Lithium in Carboxymethylcellulose Gel Electrolytes for Electrochromic Devices
No full textThe use of energy-saving devices is becoming increasingly common, as they optimize the use of energy resources and reduce waste. The study presented below aimed to develop polymeric electrolyte gels based on sodium carboxymethyl cellulose (NaCMC), with the addition of Li+ compound salts to enhance ionic conduction, thus demonstrating good electrochemical properties for application in electrochromic or energy-efficient devices. These gels were obtained by dissolving the natural polymer NaCMC in distilled water—two materials considered essential for the production of biodegradable and non-toxic materials. Three components were also added: a plasticizer, a crosslinker, and an ionic salt, which were stirred until a homogeneous polymer gel was formed. The electrolytes were prepared with different concentrations of polymer and Li+ salt. The samples underwent electrochemical analyses (EIS, VC, and VL), XRD and FTIR characterization, and thermal analyses (DSC and TGA). Viscosity, transmittance, and appearance analyses were also performed, with some analyses performed with weekly differentiation. The results demonstrated efficient ion exchange of these gels, with the best having a conductivity of 2.90x10-3 S.cm-1 . They also demonstrated good transparency and homogeneity, compared to other studies, in addition to viscosity values that exhibited a balance between agglutination and ion mobility.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESO uso de dispositivos que proporcionam economia de energia elétrica é a cada dia mais efetuado, estes otimizam o uso de recursos energéticos e diminuem desperdícios. O estudo apresentado a seguir teve como objetivo o desenvolvimento de eletrólitos poliméricos géis à base de carboximetilcelulose de sódio (NaCMC), com adição de sais compostos de Li+ para potencialização da condução iônica, e assim, a apresentação de boas propriedades eletroquímicas para aplicação em dispositivos eletrocrômicos ou dispositivos de eficiência energética. Estes géis foram obtidos através da dissolução do polímero natural NaCMC em água destilada, duas matérias que podem ser consideradas essenciais para produção de materiais biodegradáveis e atóxicos. Sendo adicionados também três componentes como plastificante, reticulante e sal iônico, que passaram por agitação até a formação do gel polimérico de aparência homogênea. Os eletrólitos foram preparados com diferentes concentrações de polímero e sal de Li+ . As amostras foram sujeitas as análises eletroquímicas de EIE, VC e VL, realização de caracterizações de DRX e FTIR, análises térmicas de DSC e TGA. Ainda, foram feitas análises de viscosidade, transmitância e aparência, sendo algumas análises realizadas com diferenciação semanal. Tendo os resultados, as análises mostraram eficiência na troca iônica destes géis, sendo o melhor com condutividade de 2,90x10-3 S.cm-1 , mostraram também, boa transparência e homogeneidade, comparados à outros estudos vistos, além de valores de viscosidade que apresentam um equilíbrio entre aglutinação e mobilidade iônica
Guia da Pessoa Servidora: UFPel 2025
No full textEste guia reúne informações importantes sobre a estrutura organizacional da universidade, direitos e deveres dos/as servidores/as, orientações administrativas, além de apresentar os serviços e canais de apoio oferecidos pela Pró-Reitoria de Gestão com Pessoas (PROGEP). Esperamos que ele seja um guia útil e acolhedor para facilitar sua adaptação e integração ao ambiente institucional
Interfaces in the construction of phonological knowledge: the lateral in syllabic Coda
No full textO artigo trata do processo de aquisição da linguagem por crianças brasileiras, focalizando a construção do conhecimento fonológico de unidades segmentais da língua, especificamente da líquida lateral /l/. A discussão contempla a análise da estrutura interna do segmento, a constituição silábica da Coda, o comportamento morfofonológico do segmento e a relação fonologia/ortografia estabelecida no processo de aquisição da escrita. A possibilidade de mudança nas representações em um processo continuado de desenvolvimento do conhecimento fonológico é considerada com base na proposta de Boersma (2011)
Impacto da pandemia da COVID-19 na vida dos adolescentes da coorte de nascimentos de Pelotas, Rio Grande do Sul, Brasil, de 2004
No full textInsights into the experiences of adolescents during the COVID-19 pandemic are crucial for understanding the extent of their impact and guiding future responses to similar challenging events. This study aims to describe the effects of the pandemic on different aspects of adolescents’ lives and examine how they varied according to socioeconomic, family, and individual characteristics. We used data from a subsample of the 2004 Pelotas (Brazil) birth cohort to investigate the reported impacts of the COVID-19 pandemic on adolescents (N = 1,806; mean age = 17.41, range: 16.73-17.95). We investigated a range of issues and impacts caused by the pandemic and social distancing measures, considering their influence on various aspects of life. Additionally, we evaluated a spectrum of socioeconomic, family, and individual variables. Data were collected via in-person interviews from August to December 2021. Roughly 20% of adolescents have reported significant disruptions in their lives due to the COVID-19 pandemic. The effects of the pandemic were more pronounced among females, private school attendees, non-beneficiaries of the government cash transfer benefit (Brazil Assistance – Auxílio Brasil), and adolescents who reported having a regular or poor health status. Adolescents have shared a multitude of stressors and concerns directly linked to the pandemic, underscoring a notable trend of heightened impacts among female adolescents. The COVID-19 pandemic has had far-reaching consequences on various aspects of adolescents’ daily lives. Recognizing the perspectives of adolescents in this challenging period is crucial for effectively addressing their needs in the post-pandemic society
Development of polymeric nanocomposites for application as thermal and bactericidal coatings in civil construction
No full textThe optimization of the thermal performance of buildings, along with the promotion of
healthier indoor environments, is a continuous demand in the construction sector. In
this context, the research and application of materials that enhance the energy and
environmental efficiency of buildings becomes essential. Nanometric-scale materials,
known as nanomaterials, exhibit interesting properties that, when applied in small
quantities in the production of nanocomposite materials, can improve or develop new
functionalities. Examples include graphene oxide (GO) and silver nanoparticles
(AgNPs), which are nanomaterials that demonstrate antibacterial properties,
mechanical strength, and thermal stability, among other properties. Aiming to
contribute to the improvement of thermal comfort, combined with cleanliness and
hygiene, in long-term occupancy environments, this research focuses on the
development of hybrid materials incorporating AgNPs and GO into polymeric matrices
for use as coatings (paint) in civil construction. In the first stage of the research, GO
and AgNPs were synthesized, and the experimental conditions for developing
nanocomposites using latex technology were optimized. The proportions of the
nanostructures, the concentration of the AgNPs solution, and substrate tests were
defined. The precursor materials were characterized by UV-vis spectroscopy and
atomic force microscopy (AFM), GO by potentiometric titration and thermogravimetric
analysis (TGA), and AgNPs by X ray diffraction (XRD). The films were morphologically
characterized by AFM and scanning electron microscopy (SEM). Structural analyses
were also performed, including infrared spectroscopy, Raman spectroscopy,
mechanical and thermal analyses using infrared thermography. To assess antibacterial
activity, microbiological analysis was conducted according to the CLSI M02 protocol,
with modifications as necessary. The results show that the synthesis of the precursor
materials aligns with the literature, displaying the characteristic peaks of GO and
AgNPs. The XRD results of AgNPs confirm the reduction of silver ions to metallic silver
nanoparticles. SEM results demonstrate good homogeneity of the nanocomposites,
with no loose structures and nanoparticles well adhered to the polymer matrix. AFM
images reveal that the presence of CTAB aids in the coalescence process of latex
particles, and that sample roughness increases with the concentration of
reinforcements. Furthermore, the nanocomposite samples exhibited lower hardness
than the pure matrix, as well as greater adhesiveness. FTIR spectroscopy indicated
that the incorporation of nanostructures does not alter the matrix structure. In tensile deformation mechanical analyses, the isolated presence of reinforcements in the
matrix, as well as most nanocomposites, increased the Young’s modulus; however,
the sample with both components in intermediate proportions – 1AgNP1GO – showed
greater flexibility and elongation. Microbiological analyses did not indicate antimicrobial
or antifungal activity of the nanocomposites, which may suggest particle aggregation,
concentration issues, or isolation by the matrix. Thermographic analyses revealed that
the 2AgNP2GO nanocomposite exhibited a surface temperature difference of up to -
4°C compared to other samples, indicating its potential as a promising coating material
to enhance the thermal performance of buildings.Sem bolsaA otimização do desempenho térmico das edificações, juntamente com a promoção de ambientes internos mais salubres, constitui uma demanda contínua no setor da construção civil. Nesse contexto, torna-se imprescindível a pesquisa e aplicação de materiais que potencializem a eficiência energética e ambiental das edificações. Os materiais em escala nanométrica, chamados nanomateriais, apresentam propriedades interessantes que, quando aplicados em pequenas quantidades na produção de materiais nanocompósitos, podem melhorar ou desenvolver novas propriedades. Alguns exemplos são o óxido de grafeno (GO) e as nanopartículas de prata (AgNPs), nanomateriais que apresentam propriedades antibacterianas, resistência mecânica, estabilidade térmica, entre outras. Visando contribuir para a melhoria do conforto térmico aliado à limpeza e higienização dos ambientes de permanência prolongada, essa pesquisa visa o desenvolvimento de materiais híbridos de AgNPs e GO incorporados em matrizes poliméricas para aplicação como revestimento (pintura) na construção civil. Na primeira etapa da pesquisa, foram sintetizados o GO e as AgNPs, e otimizada a condição experimental para desenvolvimento dos nanocompósitos pela tecnologia do látex. Foram definidas as proporções das nanoestruturas, assim como a concentração da solução de AgNPs, e testes de substrato. Os materiais precursores foram caracterizados por UV-vis e microscopia de força atômica (AFM), o GO por titulação potenciométrica e análise termogravimétrica (TGA), e as AgNPs por difração de raios x (DRX). Os filmes foram caracterizados morfologicamente por AFM e microscopia eletrônica de varredura (MEV). Ainda, foram realizadas análises estruturais como espectroscopia no infravermelho, Raman, análises mecânicas e térmicas por termografia no infravermelho. Para a obtenção da atividade antibacteriana foi realizada a análise microbiológica conforme o método descrito no protocolo M02 do CLSI, com modificações. Os resultados mostram que a síntese dos materiais precursores está de acordo com a literatura, mostrando os picos característicos do GO e das AgNPs. Os resultados de DRX das AgNPs mostram que houve a redução de íons prata para prata metálica em nanopartículas; os resultados de MEV apresentam a boa homogeneidade dos nanocompósitos, sem estruturas soltas e com as nanopartículas bem aderidas à matriz polimérica. Nas imagens de AFM pode-se observar que a presença do CTAB auxilia no processo de coalescimento das partículas de látex, assim como a rugosidade das amostras aumenta à medida que a concentração dos reforços também aumenta. Ainda, as amostras dos nanocompósitos apresentaram dureza menor que a matriz pura, assim como uma maior adesividade. A espectroscopia FTIR mostrou que a incorporação das nanoestruturas não altera a estrutura da matriz. Nas análises mecânicas em tensão-deformação, a presença isolada dos reforços na matriz, assim como a maioria dos nanocompósitos, aumenta o módulo de Young, porém a amostra com os dois componentes em proporções intermediárias – 1AgNP1GO – apresentou maior flexibilidade e alongamento do material. As análises microbiológicas não apontaram atividades antimicrobianas e antifúngicas dos nanocompósitos, podendo ser um indicativo do agregamento das partículas, concentração ou isolamento pela matriz. Nas análises termográficas pode se observar que o nanocompósito 2AgNP2GO apresentou uma diferença de temperatura superficial de até -4°C comparado às demais amostras, provando ser uma alternativa para utilização como revestimentos que auxiliem no desempenho térmico de edificações
Integrated hydrothermal evolution of a Botucatu paleodune and a blanketing lava flow from the Serra Geral Group, Uruguaiana
No full textThe integrated hydrothermal evolution of the large Santa Otília Paleodune from the Botucatu paleoerg and the cover Catalán Flow from the Serra Geral Group is here evaluated in Uruguaiana, southern Paraná Basin. Methods included satellite images, field surveying, petrography, and U-Pb geochronology of detrital and volcanic zircon. The tops of the compound linear-barchan paleodunes are exposed in the topographic highs. Rhombi and bowls at the top of the silicified sandstone units are significant, as is the poor preservation of eolian layering. The fishbone-shaped dune tops are surrounded by the lavas. The oxidized top of the flow (upper Tier 2) overlies the reduced base (Tier 1), which consists of exposed, massive rocks in creek beds that are light gray-colored and contain small (10 cm) agate geodes and numerous silicified sandstone dikes. The youngest dated zircon grains from the sandstone are 225–300 Ma old (one 175 Ma age), and the main older age peaks are 450–600 Ma (predominant), 900–975 Ma, 1800–1900 Ma, and 2500 Ma; few Archean 2.5 Ga ages. The strongly altered volcanic zircon preserved in the reddened Catalán Flow yields a concordia-intercept age of 137.3 ±7.6 Ma. Complex processes are thus constrained in the evolution of the Botucatu Formation and the first Serra Geral lava flow