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au:BRASIL, J. L.

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Experimental and Theoretical Studies of Tailor-made Schiff Bases as Corrosion Inhibitors for Carbon Steel in HCl
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Furtado, Luana B.

; Leoni, Gabriel B.

; Nascimento, R. C.

; Santos, Pedro Henrique C.

; Henrique, Fábio J. F. S.

; Guimarães, Maria José O. C.

; Brasil, Simone L. D. C.

Materials Research

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2023, Volume 26 elocation e20220398

Abstract: En | Text: En | PDF: En

Abstract Strong acids used in industrial applications as cleaning, descaling, among others, can severely damage metallic structures, requiring corrosion inhibitors to diminish or avoid these issues. Since many conventional compounds used for this purpose may result in environmental and human health issues, eco-friendly compounds such as Schiff bases have been recently investigated. The synthesis of three novel Schiff bases (SBs) was confirmed by infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance (1H-NMR). Weight loss measurements were carried out in 1 M HCl over 303K-333K. Furthermore, the combination of these compounds with a surfactant improved the efficiencies, reaching an efficiency of 93%. Optical and scanning electron microscopies confirmed the reduced roughness and pit depths of carbon steel samples. Density-functional theory calculations for neutral forms of SBs revealed that the geometrical and the energetical parameters are similar for the three studied SBs. The geometrical results exhibited more planar structures of protonated species, improving the chemical and physical interactions between aromatic rings and metallic atoms.

https://doi.org/10.1590/1980-5373-mr-2022-0398

Levantamento de recursos e uma avaliação atual do Ensino de Astrofísica Estelar
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Paulucci, L.

; Fornazari, J. F.

; Brasil Neves, K.

; Horvath, J.E.

Revista Brasileira de Ensino de Física

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2022, Volume 44 elocation e20210226

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

O conhecimento das estrelas avançou de maneira fundamental no último século, sendo que hoje podemos descrever os processos envolvidos em seu nascimento, evolução e morte. No entanto, a transposição do conhecimento científico estelar para a sala de aula não foi feita de maneira ampla ou tem sido feita em geral de forma fragmentada e parcial. Apresentamos aqui um levantamento sobre os trabalhos desenvolvidos nas últimas décadas para o ensino de Astrofísica Estelar (focado no material disponível em língua portuguesa) de modo a organizar e facilitar o trabalho da ampliação da abordagem deste tópico junto a estudantes, em particular no ensino básico, além de algumas sugestões de aplicações que poderão enriquecer o trabalho dos professores. Apresentamos também uma avaliação crítica do panorama dentro do ensino brasileiro.

Our knowledge about stars has fundamentally advanced over the last century and today we can describe the processes involved in their birth, evolution and death. However, the transposition of stellar scientific knowledge into the classroom has not been done in a broad way or has been done in general in a fragmented and partial way. We present here a survey of the work developed in recent decades for the teaching of Stellar Astrophysics (focused on the material available in Portuguese) in order to organize and facilitate the work of expanding the approach to this topic with students, particularly in basic education, in addition to some suggestions for applications that could enrich the work of teachers. We also present a critical assessment of the panorama within Brazilian education.

https://doi.org/10.1590/1806-9126-rbef-2021-0226

Cultivable bacterial diversity associated with bromeliad roots from ironstone outcrops in central Brazil
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Viana, T. F. C.

; Campelo, A. P. S.

; Baldani, J. I.

; Fernandes-Júnior, P. I.

; Baldani, V. L. D.

; Silva, W. M.

; Paggi, G. M.

; Brasil, M. S.

Brazilian Journal of Biology

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dec 2020, Volume 80 N. 4 Pages 872 - 880

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo Estudos sobre a diversidade bacteriana associada a plantas silvestres são raros, especialmente naqueles que crescem em associação com bromélias. No presente estudo, isolamos e identificamos bactérias epífitas e endofíticas das raízes das bromélias Dyckia excelsa, D. leptostachya e Deuterocohnia meziana ocorrentes nas “cangas” no Pantanal do Mato Grosso do Sul, Brasil. As bactérias epifíticas foram isoladas de raízes lavadas, enquanto as bactérias endofíticas foram isoladas de raízes desinfestadas na superfície. Representantes bacterianos correspondentes a cada perfil do BOX-PCR, bem como aqueles que não resultaram em amplificações, foram selecionados para o sequenciamento do gene 16S rDNA. Os dados da BOX-PCR mostraram diversidade intragênica e intraespecífica e puderam discriminar cepas e identificar suas características fenotípicas. A seqüência do gene 16S rDNA e a análise filogenética mostraram uma maior ocorrência de cepas pertencentes ao gênero Bacillus do que as bactérias Mycobacterium e Brevibacterium, encontradas em menor número. Espécies do gênero Bacillus são bem conhecidas por sua capacidade de esporulação e maior sobrevida em locais áridos, como as “cangas”. Este estudo mostrou claramente que as espécies de bromélias representam um vasto reservatório de diversidade de comunidades bacterianas, e as linhagens cultiváveis podem representar uma nova fonte para a prospecção biotecnológica.

Abstract Studies on the bacterial diversity associated with wild plants are rare, especially on those that grow in association with bromeliads. In the present study, we isolated and identified epiphytic and endophytic bacteria from the roots of the bromeliads Dyckia excelsa, Dyckia leptostachya and Deuterocohnia meziana occurring in the “cangas” in the Pantanal from Mato Grosso do Sul State, Brazil. The epiphytic bacteria were isolated from washed roots, while the endophytic bacteria were isolated from surface disinfested roots. Bacterial representatives corresponding to each BOX-PCR fingerprint, as well as those that did not result in amplicons, were selected for 16S rDNA gene sequence analysis. The BOX-PCR data showed intrageneric and intraspecific diversity and could discriminate strains and identify their phenotypic characteristics. The 16S rDNA gene sequence and phylogeny analysis showed a higher occurrence of strains belonging to the genus Bacillus than Mycobacterium and Brevibacterium, which were found in lower numbers. Species from the Bacillus genus are well known for their sporulation capacity and longer survival in arid locations, such as the “cangas”. This study clearly showed that the bromeliad species represent a vast reservoir of bacterial community diversity, and the cultivable strains represent a new source for biotechnological prospecting.

https://doi.org/10.1590/1519-6984.224982 476 downloads

COVID-19 with and without pneumonia: clinical outcomes in the internal medicine ward
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Melendi, Santiago E.

; Pérez, María M.

; Salas, Cintia E.

; Haedo, Mariana F.

; Xavier, Franco B.

; Navarrete, Jandry D. Saltos

; Aguirre, Camila

; Baleta, María L.

; Balsano, Facundo J.

; Caldano, Mariano G.

; Colignon, María G.

; De Oliveira Brasil, Thayana

; De Wolodimeroff, Nicolás

; Déramo Aquino, Andrea I.

; Fernández De Córdova, Ana G.

; Fontan, María B.

; Galvagno, Florencia I.

; Iturrieta Araya, Noelia S.

; Mollinedo Cruz, Volga S.

; Olivero, Agustín

; Pestalardo, Ignacio

; Ricciardi, María

; Vera Rueda, María L.

; Villaverde, María C.

; Mauri, Marcela Lauko

; Ujeda, Carlos

; Leis, Rocío

Medicina (Buenos Aires)

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dec 2020, Volume 80 Suppl. 6 Pages 56 - 64

Abstract: En Es | Text: En Es | PDF: En | PDF: Es

Abstract The clinical features of COVID-19 differ substantially upon the presence (or absence) of viral pneumonia. The aim of this article was to describe the clinical characteristics of COVID-19 patients admitted to the Internal Medicine ward, as divided into those with and without pneumonia. This single-center prospective cohort study was conducted in a tertiary teaching public hospital in Buenos Aires City named Hospital General de Agudos Carlos G. Durand. Baseline data collection was performed within 48 hours of admission and patients were followed until discharge or in-hospital death. Epidemiological, clinical, laboratory, and radiological characteristics together with treatment data were obtained from the medical records. Of the 417 included, 243 (58.3%) had pneumonia. Median age was 43 years (IQR:32-57) and 222 (53.2%) were female. The overall crude case-fatality rate was 3.8%. None of the COVID-19 patients without pneumonia developed critical disease, required invasive mechanical ventilation nor died during hospitalization. However, 7 (4%) developed severe disease during follow-up. Among patients with COVID-19 pneumonia, in-hospital mortality rate was 6.6%, severe disease developed in 81 (33.3%), critical disease in 23 (9.5%), and 22 (9.1%) were admitted to the intensive care unit. A largely good prognosis was observed among COVID-19 patients without pneumonia, still, even among this group, unfavorable clinical progression can develop and should be properly monitored. Critical illness among patients with COVID-19 pneumonia was frequent and observed rates from this cohort provide a sound characterization of COVID-19 clinical features in a major city from South America.

Resumen Las características clínicas del COVID-19 difieren sustancialmente según la presencia (o ausencia) de neumonía viral. El objetivo de este artículo fue describir las características clínicas de los pacientes con COVID-19 internados en el servicio de Clínica Médica, divididos en pacientes con y sin neumonía. Fue un estudio de cohorte prospectivo, con base en un único centro, realizado en un hospital público de la ciudad de Buenos Aires: Hospital General de Agudos Carlos G. Durand. La recolección basal de datos se realizó dentro de las 48 horas del ingreso y los pacientes fueron seguidos hasta el alta o la muerte hospitalaria. Las características epidemiológicas, clínicas, de laboratorio y radiológicas junto con los datos del tratamiento se obtuvieron de la historia clínica. De los 417 incluidos, 243 (58.3%) tenían neumonía. La mediana de edad fue de 43 años (RIC: 32-57) y 222 (53.2%) eran mujeres. La tasa global de letalidad fue del 3.8%. Ninguno de los pacientes con COVID-19 sin neumonía desarrolló enfermedad crítica, requirió ventilación mecánica invasiva ni falleció durante la hospitalización. Sin embargo, 7 (4%) desarrollaron enfermedad grave durante el seguimiento. Entre aquellos con neumonía COVID-19, la tasa de mortalidad hospitalaria fue del 6.6%, se desarrolló enfermedad grave en 81 (33.3%), enfermedad crítica en 23 (9.5%) y 22 (9.1%) fueron trasladados a la unidad de cuidados intensivos. Los pacientes con COVID-19 sin neumonía presentaron buen pronóstico; sin embargo, incluso en este grupo, se observaron algunos con progresión clínica desfavorable, por lo que se requirió seguimiento adecuado. En los pacientes con neumonía por COVID-19, el desarrollo de enfermedad crítica fue frecuente y las tasas observadas en esta cohorte proporcionan una caracterización sólida de las características clínicas de los pacientes con COVID-19 en una importante ciudad de América del Sur.

174 downloads

Transport of broilers: load microclimate during Brazilian summer
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Barbosa Filho, José A. D.

; Queiroz, Marília L. V.

; Brasil, Daniel de F.

; Vieira, Frederico M. C.

; Silva, Iran J. O.

Engenharia Agrícola

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jun 2014, Volume 34 N. 3 Pages 405 - 412

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Este trabalho foi conduzido com o objetivo de caracterizar o perfil microclimático da carga de caminhões de transporte de frangos de corte sob condições comerciais, durante o verão brasileiro, por meio do monitoramento constante das variáveis meteorológicas (temperatura e umidade relativa do ar). Foram monitorados três carregamentos, da saída das aves da granja até a chegada ao abatedouro, em que se consideraram fatores como a distância e os turnos (manhã, tarde e noite). Para a obtenção do perfil das variáveis ambientais durante o transporte dos animais, foram instaladas ao longo da carga miniestações meteorológicas (Data Loggers) que permitiram determinar o microclima a que as aves foram submetidas e visualizar o perfil do Índice Entalpia de Conforto (IEC). Com estes valores, foi possível a classificação das regiões da carga de acordo com os limites de conforto térmico para frangos de corte, na sexta semana de vida. Os dados de temperatura, umidade relativa do ar e do IEC na carga foram analisados, utilizando-se da geoestatística pelo método de krigagem ordinária. O turno da tarde foi o mais crítico, com ênfase no conforto térmico das aves, sendo que as partes central e traseira da carga do caminhão foram as mais problemáticas, portanto as mais propícias à ocorrência de perdas.

The objective of this study was to characterize the microclimatic profile of broiler transport trucks under commercial conditions, in the summer, by continuous monitoring of environmental variables (temperature and air relative humidity). Three loads were monitored from farm to slaughterhouse, considering factors such as distance and day periods (morning, afternoon, and night). To obtain the profile of the environmental variables during journey, data loggers, that determined the microclimate to which birds were submitted, were installed in the trucks; data loggers also allowed visualization of the Enthalpy Comfort Index (ECI) so that load regions could be classified according to heat comfort limits for 6-week old poultries. Temperature, relative humidity, and ECI in the truck were analyzed, using geostatistics, by the ordinary kriging method. The afternoon was the most critical period, and truck central and rear regions were most problematic for chickens, thus most susceptible to losses.

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Influence of the synthesis conditions on the characteristics and metal adsorption properties of the 3-(1,4-phenylenediamine)propylsilica xerogel
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Vaghetti, J. C. P

; Brasil, J. L.

; Costa, T. M. H

; Lima, E. C.

; Benvenutti, E.V

Eclética Química

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2005, Volume 30 N. 4 Pages 43 - 49

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

O xerogel híbrido 3-(1,4-fenilenodiamina)propilsílica foi obtido partindo-se de duas quantidades de precursor orgânico (5 e 8 mmol) para 22 mmol de TEOS, na síntese. As amostras dos xerogéis foram caracterizadas usando-se análise elementar CHN, isotermas de adsorção e dessorção de N2 e termoanálise no infravermelho. Os xerogéis foram usados como adsorventes metálicos para Cu2+, Cd2+ e Pb2+ em meio aquoso, na faixa de concentração de 10-3 até 10-5 mmol l-1. A quantidade de precursor orgânico adicionado na síntese influencia nas características do xerogel como morfologia e estabilidade térmica, como também na sua capacidade de adsorção de metais.

The hybrid 3-(1,4-phenylenediamine)propylsilica xerogel was obtained starting from two different organic precursor quantity (5 and 8 mmol) to 22 mmol of TEOS, in the synthesis. The xerogel samples were characterized by using CHN elemental analysis, N2 adsorption-desorption isotherms, infrared thermal analysis. The xerogel was used as metal sorbent for Cu2+, Cd2+ and Pb2+ in aqueous solution with concentration range of 10-3 to 10-5 mmol l-1. The quantity of organic precursor added in the synthesis influences the characteristics of the xerogel as morphology and thermal stability, as well as the metal adsorption capacity.

1221 downloads

A short note on a nonlinear system vibrations under two non-ideal excitations
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Palacios, J. L.

; Balthazar, J. M.

; Brasil, R. M. L. R. F.

Journal of the Brazilian Society of Mechanical Sciences and Engineering

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dec 2003, Volume 25 N. 4 Pages 391 - 395

Abstract: En | Text: En | PDF: En

This paper describes a nonlinear phenomenon in the dynamical behavior of a nonlinear system under two non-ideal excitations: the self-synchronization of unbalanced direct current motors. The considered model is taken as a Duffing system that is excited by two unbalanced direct current motors with limited power supplies. The results obtained by using numerical simulations are discussed in details

2022 downloads

On non-ideal and non-linear portal frame dynamics analysis using bogoliubov averaging method
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Palacios, J. L.

; Balthazar, J. M.

; Brasil, R. M. L. R. F.

Journal of the Brazilian Society of Mechanical Sciences

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nov 2002, Volume 24 N. 4 Pages 257 - 265

Abstract: En | Text: En | PDF: En

We apply the Bogoliubov Averaging Method to the study of the vibrations of an elastic foundation, forced by a Non-ideal energy source. The considered model consists of a portal plane frame with quadratic nonlinearities, with internal resonance 1:2, supporting a direct current motor with limited power. The non-ideal excitation is in primary resonance in the order of one-half with the second mode frequency. The results of the averaging method, plotted in time evolution curve and phase diagrams are compared to those obtained by numerically integrating of the original differential equations. The presence of the saturation phenomenon is verified by analytical procedures.

5830 downloads

Analysis of Regular and Irregular Dynamics of a Non Ideal Gear Rattling Problem
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Souza, S. L. T. de

; Caldas, I. L.

; Balthazar, J. M.

; Brasil, R. M. L. R. F.

Journal of the Brazilian Society of Mechanical Sciences

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may 2002, Volume 24 N. 2 Pages 111 - 114

Abstract: En | Text: En | PDF: En

This paper presents a study on the dynamics of the rattling problem in gearboxes under non-ideal excitation. The subject has being analyzed by a number of authors such as Karagiannis and Pfeiffer (1991), for the ideal excitation case. An interesting model of the same problem by Moon (1992) has been recently used by Souza and Caldas (1999) to detect chaotic behavior. We consider two spur gears with different diameters and gaps between the teeth. Suppose the motion of one gear to be given while the motion of the other is governed by its dynamics. In the ideal case, the driving wheel is supposed to undergo a sinusoidal motion with given constant amplitude and frequency. In this paper, we consider the motion to be a function of the system response and a limited energy source is adopted. Thus an extra degree of freedom is introduced in the problem. The equations of motion are obtained via a Lagrangian approach with some assumed characteristic torque curves. Next, extensive numerical integration is used to detect some interesting geometrical aspects of regular and irregular motions of the system response.

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