Estudo comparativo da substituição gradativa de agregado graúdo na forma lamelar pela forma cúbica nas propriedades do concreto

TCC (graduação) - Universidade Federal de Santa Catarina. Campus Joinville. Engenharia de Infraestrutura.Mesmo sendo um material utilizado a milhares de anos, o concreto vem sendo constantemente estudado, visando cada vez mais melhorar suas propriedades e reduzir seu custo. Uma forma eficiente de se fazer isto é melhorando as características de seus agregados, que compõem a maior parte do volume do concreto. Neste trabalho, a análise foi realizada no agregado graúdo, mais especificamente na brita 1. Esta brita de forma lamelar foi beneficiada de modo a reduzir seu índice de forma e com este material foram produzidos concretos para dois traços de diferentes resistências. Para cada traço foi feita a substituição da brita de forma lamelar pela brita beneficiada em 0%, 50% e em 100%. Os resultados mostraram que há um incremento de resistência progressivo conforme o aumento da substituição. Este ganho no traço de Fck 15 MPa foi de 27,53% para 50% de substituição e 55,27 % para 100 %. O traço de Fck 35 MPa apresentou, respectivamente, 7,09 % e 10,69 % para 50 % e 100 % de substituição.Although it has been used for thousands of years, concrete has been constantly being studied, aiming to improve its properties and reduce its cost. An efficient way to do this is to improve the characteristics of your aggregates, which make up most of the volume of concrete. In this work, the analysis was performed in the aggregate, more specifically in crushed stone 1. This lamellar crushed stone was beneficiated in order to reduce its shape factor and with this material were produced concrete for two traces of different resistances. For each trace the substitution of the crushed stone was carried out by 0%, 50% and 100%. The results showed that there is an progressive increase of resistance as the substitution increases. This gain in the trace of Fck 15 MPa was 27.53% for 50% substitution and 55.27% for 100%. The Fck trace 35 MPa presented, respectively, 7.09% and 10.69% for 50% and 100% substitution

Equivalência de escalas de distância psíquica de item único: um teste no Brasil

Despite the broad acceptance of the concept of psychic distance, problems related to measuring the construct have persisted in empirical studies. Although researchers have developed and used a variety of instruments, no study has, thus far, concerned itself with making a comparative evaluation for the purpose of assessing their equivalence. The present study sought to evaluate several single-item scales to measure psychic distance as a summary construct. Four data collection instruments in the literature were identified, and applied to a final sample of 365 university students. Approximately one fourth of the sample answered each questionnaire. A range of statistical tests were carried out in order to identify the features of the respective instruments as well as to assess their equivalence and validity. The results enabled to compare features and showed that only two of the instruments produced equivalent results. All of the scales correlated strongly; however, the performance of the scales in the tests did vary. The Stöttinger and Schlegelmilch (1998) scale has the capacity to be used with a greater range of statistical tests and presented superior results in practically all of the tests carried out. It is the scale recommended to researchers wishing to utilize single-item measures of psychic distance.Key words: psychic distance, measurement scales, summary construct, single-item scales.Apesar da ampla aceitação do conceito de distância psíquica, ainda persistem problemas relativos à medição do construto. Embora os pesquisadores tenham desenvolvido e utilizado vários instrumentos, nenhum estudo, até o momento, preocupou-se em realizar uma avaliação comparativa com o propósito de verificar a equivalência das escalas. O presente estudo procurou contribuir para a avaliação de diversos instrumentos que utilizam escala única para medir a distância psíquica como construto-síntese. Quatro instrumentos de coleta de dados foram identificados na literatura e aplicados a uma amostra final de 365 universitários. Aproximadamente um quarto da amostra respondeu a cada questionário. Diversos testes estatísticos foram utilizados para identificar as características de cada instrumento assim como para avaliar sua equivalência e validade. Os resultados obtidos permitiram comparar as características, mostrando que apenas dois instrumentos produziram resultados equivalentes. Todas as escalas se mostraram fortemente correlacionadas, mas o desempenho das escalas nos testes mostrou variações. A escala de Stöttinger e Schlegelmilch (1998) pode ser utilizada em grande variedade de testes estatísticos e apresentou resultados superiores em praticamente todos os testes realizados. Trata-se, portanto, da escala mais recomendada aos pesquisadores que desejarem utilizar uma medida de item único de distância psíquica.Palavras-chave: distância psíquica, escalas de medida, construto-síntese, escalas de item único

Equivalência de escalas de distância psíquica de item único: um teste no Brasil

Despite the broad acceptance of the concept of psychic distance, problems related to measuring the construct have persisted in empirical studies. Although researchers have developed and used a variety of instruments, no study has, thus far, concerned itself with making a comparative evaluation for the purpose of assessing their equivalence. The present study sought to evaluate several single-item scales to measure psychic distance as a summary construct. Four data collection instruments in the literature were identified, and applied to a final sample of 365 university students. Approximately one fourth of the sample answered each questionnaire. A range of statistical tests were carried out in order to identify the features of the respective instruments as well as to assess their equivalence and validity. The results enabled to compare features and showed that only two of the instruments produced equivalent results. All of the scales correlated strongly; however, the performance of the scales in the tests did vary. The Stöttinger and Schlegelmilch (1998) scale has the capacity to be used with a greater range of statistical tests and presented superior results in practically all of the tests carried out. It is the scale recommended to researchers wishing to utilize single-item measures of psychic distance.Key words: psychic distance, measurement scales, summary construct, single-item scales.Apesar da ampla aceitação do conceito de distância psíquica, ainda persistem problemas relativos à medição do construto. Embora os pesquisadores tenham desenvolvido e utilizado vários instrumentos, nenhum estudo, até o momento, preocupou-se em realizar uma avaliação comparativa com o propósito de verificar a equivalência das escalas. O presente estudo procurou contribuir para a avaliação de diversos instrumentos que utilizam escala única para medir a distância psíquica como construto-síntese. Quatro instrumentos de coleta de dados foram identificados na literatura e aplicados a uma amostra final de 365 universitários. Aproximadamente um quarto da amostra respondeu a cada questionário. Diversos testes estatísticos foram utilizados para identificar as características de cada instrumento assim como para avaliar sua equivalência e validade. Os resultados obtidos permitiram comparar as características, mostrando que apenas dois instrumentos produziram resultados equivalentes. Todas as escalas se mostraram fortemente correlacionadas, mas o desempenho das escalas nos testes mostrou variações. A escala de Stöttinger e Schlegelmilch (1998) pode ser utilizada em grande variedade de testes estatísticos e apresentou resultados superiores em praticamente todos os testes realizados. Trata-se, portanto, da escala mais recomendada aos pesquisadores que desejarem utilizar uma medida de item único de distância psíquica.Palavras-chave: distância psíquica, escalas de medida, construto-síntese, escalas de item único

Preliminary assessment of cardiac short term safety and efficacy of manganese chloride for cardiovascular magnetic resonance in humans

<p>Abstract</p> <p>Background</p> <p>Manganese based agents are intracellular and accumulate inside myocytes allowing for different imaging strategies compared to gadolinium contrasts. While previous agents release manganese very slowly in the circulation, MnCl₂allows for rapid Mn2⁺uptake in myocytes, creating a memory effect that can be potentially explored. Data on animal models are very encouraging but the safety and efficacy of this approach in humans has not yet been investigated. Therefore, our objectives were to study the safety and efficacy of a rapid infusion of manganese chloride (MnCl₂) for cardiovascular magnetic resonance (CMR) in humans.</p> <p>Methods</p> <p>Fifteen healthy volunteers underwent a CMR scan on a 1.5 T scanner. Before the infusion, cardiac function was calculated and images of a short axis mid-ventricular slice were obtained using a 2D and 3D gradient-echo inversion recovery (GRE-IR) sequence, a phase-sensitive IR sequence and a single breath-hold segmented IR prepared steady-state precession acquisition for T₁calculations. MnCl₂was infused over three minutes at a total dose of 5 μMol/kg. Immediately after the infusion, and at 15 and 30 minutes later, new images were obtained and cardiac function re-evaluated.</p> <p>Results</p> <p>There was a significant decrease in T₁values compared to baseline, sustained up to 30 minutes after the MnCl₂infusion (pre,839 ± 281 ms; 0 min, 684 ± 99; 15 min, 714 ± 168; 30 min, 706 ± 172, P = 0.003). The 2D and 3D GRE-IR sequence showed the greatest increase in signal-to-noise ratio compared to the other sequences (baseline 6.6 ± 4.2 and 9.7 ± 5.3; 0 min, 11.3 ± 4.1 and 15.0 ± 8.7; 15 min, 10.8 ± 4.0 and 16.9 ± 10.2; 30 min, 10.6 ± 5.2 and 16.5 ± 8.3, P < 0.001 for both). There was a slight increase in systolic pressure and heart rate after three and four minutes of the infusion with normalization of these parameters thereafter. Patients showed good tolerance to MnCl₂with no major adverse events, despite all reporting transient facial flush.</p> <p>Conclusions</p> <p>In the short term, MnCl₂appears safe for human use. It effectively decreases myocardium T₁, maintaining this effect for a relatively long period of time and allowing for the development of new imaging strategies in CMR, especially in ischemia research.</p

OCORRÊNCIA DE MERCÚRIO EM ROCHAS, SOLOE SEDIMENTO FLUVIAL NA BACIA DO RIO IGUAÇU, ESTADO DO PARANÁ, BRASIL

Mercury contents in rocks, soil and stream sediments were determined to investigate the origin of the geochemical anomaly found in sediments of the Iguaçu River as indicated in previous studies. Except for its headwaters in the Curitiba area with Precambrian basement rocks and Cenozoic sediments of the Curitiba Basin, the Iguaçu River lies across the Paraná Basin comprising Paleozoic to Mesozoic sedimentary and volcanic rocks. In the study area, the geological units include basaltic and dacitic rocks of the Serra Geral Formation (Cretaceous) and black shales of the Irati Formation (Permian-Triassic). Total mercury was measured by thermal decomposition with atomic absorption spectrometry and Zeeman correction in volcanic rocks (0.2 to 0.4 ng/g), black shales (286 and 430 ng/g), soil (average of 103±57 ng/g, grain sizeA anomalia geoquímica de mercúrio em sedimento de corrente da bacia hidrográfica do Rio Iguaçu, Estado do Paraná, foi investigada em detalhe por meio de determinações das concentrações do metal em rochas, solo e sedimento fluvial. O Rio Iguaçu está inserido no contexto geológico da Bacia do Paraná, com exceção de suas nascentes, em Curitiba, com rochas pré-cambrianas do embasamento cristalino e sedimentos da Bacia de Curitiba. A área de estudo compreende folhelhos negros da Formação Irati, Grupo Passa Dois e rochas vulcânicas da Formação Serra Geral, Grupo São Bento. Os teores de mercúrio foram determinados por espectrometria de absorção atômica por decomposição térmica com correção do Efeito Zeeman. Foram obtidos teores de mercúrio em: rochas vulcânicas (0,2 a 0,4 ng/g), folhelhos negros (286 e 430 ng/g), solo (média de 103±57 ng/g, fraçã

Evaluation of an educational program on calcium and phosphorus metabolism for patients on hemodialysis

Estudio de cohorte evaluando efectos de programa de enseñanza-aprendizaje sobre el metabolismo y control de niveles séricos de calcio (Ca), fósforo (PO4), parathormona (PTH), producto Ca x PO4 en 33 pacientes estables en HD, randomizados para dos grupos: Control (n=17) e Intervención (n=16). El grupo Control recibió información sobre acceso vascular; el grupo Intervención, sobre metabolismo de Ca, PO4 y PTH. Cambios de conocimiento evaluadas por pruebas pre y post clases, adhesión a la terapia por dosajes laboratoriales seriados. No existió cambio significativo de conocimiento en cualquier grupo [Intervención: 8/17 vs 14/17 pacientes competentes en las etapas pre y post prueba, respectivamente (PEstudo de corte avaliando efeitos de programa de ensino-aprendizagem sobre o metabolismo e controle de níveis séricos de cálcio (Ca), fósforo (PO4), paratormônio (PTH), produto Ca x PO4, em 33 pacientes estáveis em HD, randomizados para dois grupos: Controle (n=17) e Intervenção (n=16). O grupo Controle recebeu informação sobre acesso vascular: a Intervenção sobre metabolismo de Ca, PO4 e PTH. Mudanças de conhecimento avaliadas por testes pré e pós-classe; adesão à terapia por dosagens laboratoriais seriadas. Não houve mudança significativa de conhecimento em qualquer grupo [Intervenção: 8/17 vs. 14/17 pacientes competentes no pré e pós-teste, respectivamente (PThis cohort study evaluated the effects of an educational program about metabolism and control of serum levels of calcium (Ca), phosphorus (PO4), parathormone (PTH), Ca x PO4 product on 33 stable patients on hemodialysis. Patients were randomized into two groups: control (n=17) and intervention (n=16). The control group received information on vascular access. The intervention group was informed about Ca, PO4 and PTH metabolism. The changes in knowledge were evaluated using tests. Treatment compliance was assessed by serial laboratory tests. No significant change was observed in their knowledge [intervention: 8/17 vs. 14/17 competent patients before and after class, respectively (

Study of temperature effect on macro-synthetic fiber reinforced concretes by means of Barcelona tests: An approach focused on tunnels assessment

This paper presents an experimental investigation on the applicability of the Barcelona (BCN) test to evaluate the mechanical properties of a macro-synthetic fiber reinforced concrete (MSFRC) submitted to high temperature environments (up to 600 °C). BCN tests demonstrated that the MSFRC gradually loses tensile strength an energy consumption density with increasing temperature. Temperatures of 400 °C and 570 °C shown to be critical to the MSFRC mechanical performance. The residual mechanical behavior of the macro-synthetic fibers was not affected by the temperature up to 100 °C. For higher temperatures, the reinforcement showed that may lose part of its crystallinity compromising the MSFRC post-cracking performance. The constitutive model used to determine the stress-strain curves of the MSFRC was capable to reproduce the composite behavior after the event of a fire

O ensino de termologia por meio de uma atividade lúdica: : o jogo do autódromo

This article consists of an experience report carried out during the Institutional ScholarshipProgram for Teaching Initiation (PIBID) of a Degree Course in Physics. The intervention took place at the end of the first quarter of 2019, in a 2nd year high school class at a state public school. The methodology adopted was a playful activity, in the form of a game called Autodromo, with the objective of reviewing the content of Thermology. During the application, we found the motivation and engagement of students provided by the ludic activity and also the importance of proposing activities related to the more conceptual and contextualized part of Physics. We believe that the intervention was able to reduce the degree of students' rejection of the Physics discipline, indicating a possible improvement in learning.Este artigo consiste num relato de experiência realizado durante o Programa Institucional de Bolsa de Iniciação à Docência (PIBID) de um Curso de Licenciatura em Física. A intervenção ocorreu no final do primeiro trimestre de 2019, numa turma de 2º ano do Ensino Médio de uma Escola pública estadual. A metodologia adotada foi uma atividade lúdica, na forma de um jogo denominado Autódromo, com o objetivo de revisar o conteúdo de Termologia. Durante a aplicação constatamos a motivação e o engajamento dos alunos proporcionados pela atividade lúdica e também a importância de se propor atividades relacionadas a parte mais conceitual e contextualizada da Física. Acreditamos, que a intervenção conseguiu reduzir o grau de rejeição dos alunos para com a disciplina de Física, indicando possível melhora do aprendizado

Cryopreservation of caprine ovarian tissue using glycerol and ethylene glycol

Cryopreservation of ovarian tissue may be a potential alternative for the conservation of genetically superior animals, including high milk- and meat-producing goat breeds. However, until now, no information was available concerning the cryopreservation of preantral follicles (PF) enclosed in caprine ovarian tissue. The objective of the present study was to evaluate the structural and ultrastructural characteristics of caprine PF after exposure to and cryopreservation of ovarian tissue in 1.5 and 3 M glycerol (GLY) and ethylene glycol (EG). At the slaughterhouse, each ovarian pair from five adult mixed breed goats was divided into nine fragments and randomly distributed into treatment groups. One fragment was immediately fixed for histological examination and ultrastructural analysis, after slaughter (control). Four of the ovarian fragments were equilibrated at 20 °C for 20 min in 1.8 ml of MEM containing 1.5 or 3 M GLY or EG for a toxicity test and the final four fragments were slowly frozen using these cryoprotectants at the concentrations above. After toxicity testing and freezing/thawing, the ovarian fragments were fixed for histological examination. Histological analysis showed that after toxicity testing and cryopreservation of the ovarian tissue in GLY or EG at both concentrations, the percentage of normal PF was significantly lower than controls. Ultrastructural analysis of PF frozen in 1.5 and 3 M GLY, as well as 3 M EG demonstrated that these follicles remained morphologically normal. In conclusion, we demonstrated cryopreservation of caprine PF in ovarian tissue