Katia A. S. Aquino

Federal University of Pernambuco | UFPE · Department of Nuclear Energy

Poly(vinyl chloride) (PVC) is considered one of the most versatile polymers due to its interaction with different additives. On the other hand, binary sulfides have wide applications as zinc sulfide (ZnS), one of the first discovered semiconductors. This study aims to synthesize a nanocomposite material containing nano ZnS in the PVC matrix with a...

O presente artigo versa sobre a avaliação de sequências didáticas idealizadas para o ensino de ciências que tenham potencial para desenvolver aprendizagens significativas, ou seja, que levem em consideração os conhecimentos prévios do estudante e a assimilação de novos conceitos de modo articulado, não-literal e substantivo, propiciando o surgiment...

Percursos didáticos que se amparem em perspectivas construtivistas de aprendizagem são caminhos aspirados desde o final do século XX pelos estudiosos em educação. Outrossim, o processo avaliativo é um movimento complexo que demanda do professor certo esforço na busca por evidências da consolidação da aprendizagem. Posto isto, na perspectiva de uma...

O presente artigo discute o potencial edu�cacional do Museu de Ciências Nucleares (MCN) localizado na Universidade Federal de Pernambuco, primeiro museu de Ciências Nucleares da América Latina e o único no Brasil inteiramente dedicado ao tema da ra�dioatividade e suas aplicações benéficas. Tam�bém apresenta apontamentos sobre o museu enquanto...

Formulação à base de polímero vinílico e óleo extraído da borra do café como plastificante ambientalmente amigável

Formulação à base de polímero vinílico e pó de conchas de ostras como estabilizante térmico.

Formulação à base de polímero vinílico e pó de conchas de ostras como estabilizante térmico

Terconazole (TCZ) was the first triazole antifungal drug launched in the market and has been used in the treatment of vulvovaginal candidiasis. It is also indicated to treat dermatophytosis and fungal ocular infections. However, some of the degradation products from triazole drugs have been reported to be toxic, justifying the need of further inves...

Economically viable alternatives for utilizing municipal solid waste are still a major challenge for society, especially in less developed countries. A potential pathway is using the organic fraction of municipal solid waste (OFMSW) to produce energy, biofuels, organic fertilizers, and value-added chemical compounds. We evaluated an integrated bior...

Pensando numa alternativa para um ensino mais dinâmico sobre a tabela periódica, desenvolveu-se a ferramenta TAPEQUIM - Tabela Periódica dos Elementos Químicos. A TAPEQUIM se trata de uma tabela periódica que tem como objetivo possibilitar aos professores e estudantes a utilização de uma ferramenta tecnológica com mobilidade e que promova a interaç...

Na indústria de petróleo são geradas incrustações em equipamentos a partir da precipitação de sais inorgânicos presentes na água de injeção. Junto com esses sais, precipitam-se na forma mineral os radionuclídeos Ra-226 e Ra-228, cuja presença em altos níveis aumenta a exposição humana à radiação ionizante. Aqui avaliamos a viabilidade de dois métod...

A poluição litorânea está na lista dos graves problemas ambientais que prejudicam a sociedade e a manutenção dos ecossistemas. Considerando esse cenário e a complexidade que envolve os problemas ambientais é importante que as escolas, não mais de forma ingênua, realizem ações que conversem com os diversos saberes curriculares com uso de ferramentas...

Layered double hydroxides (LDH) have been extensively studied for a broad range of applications because their ease synthesis and chemical/crystal structure provides opportunities of combination with polymers forming nanocomposites. In this way, we have attempted to develop polymethylmethacrylate/LDH (PMMA/LDH) nanocomposites by using nonmodified Mg...

O aplicativo gamificado RadiAção foi desenvolvido a fim de ser um recurso didático de ensino e aprendizagem da Ciência Nuclear e suas tecnologias para estudantes do Ensino Básico, contribuindo para uma aprendizagem interativa, dinâmica e participativa deste tema. Fundamentado no conceito de gamificação e em referenciais teóricos sobre a Ciência Nuc...

This work aims at the application of chitosan-based materials in the treatment of oil incrustations containing Ra-226 and Ra-228 after an initial extraction process. Acid digestion in ultrasound and microwave of oil resulted in radium extraction. In this way, adsorption assay with chitosan powder (without modification) and chitosan bead (chemical m...

Pre-treatment is one of main economic and technological challenges to render feasible the production of biofuels and chemical compounds from lignocellulosic biomass. Alkaline hydrogen peroxide (AHP) is the most used pre-treatment and recycling of its liquid fraction can help reduce production costs. The effects of four AHP concentrations (1, 3.5, 5...

Chitosan is a biopolymer derived from chitin and the most abundant polysaccharide in nature after cellulose. This biopolymer has been applied in different areas due its biodegradability and biocompatibility properties. Modifications of chitosan structure by cross-linking chemical agents can alter its physical, chemical, and morphological characteri...

Buscar e elaborar estratégias para um efetivo processo de ensino-aprendizagem na educação básica e maneá-las no contexto das Tecnologias Digitais da Informação e Comunicação (TDIC) é uma possibilidade promissora para a construção de conhecimentos significativos e críticos nos estudantes. Nesse sentido, esse estudo objetivou caracterizar e validar e...

O progresso científico e tecnológico da Sociedade exige do contexto educacional a utilização de ferramentas alinhadas a estes avanços. O trabalho realizado trata da aplicação de uma ferramenta tecnológica, a Flexquest, sobre a temática de dietas para o ensino de reações orgânicas no 3o ano do ensino médio a partir da perspectiva da teoria da flexib...

O desafio de promovermos uma aprendizagem significativa crítica no ensino de ciências está relacionado à utilização de estratégias que contribuam para a negociação de significados e que sejam capazes de promover uma Aprendizagem Significativa. Com base nisso, buscamos avaliar como a utilização da argumentação pode potencializar a construção e estab...

Este estudo remete à criação e validação de uma FlexQuest: ferramenta que conjuga a tecnologia digital à Teoria da Flexibilidade Cognitiva, com a finalidade de promover uma aprendizagem significativa em estudantes da Educação Básica. Nesse sentido, os elementos promotores de flexibilização do conhecimento foram idealizados e configuraram uma FlexQu...

O mapa conceitual é uma ferramenta muito utilizada no contexto educacional para apoiar o estudante na articulação do conhecimento e o professor como instrumento de avaliação. Apoiado em uma concepção de linguagem como constitutiva da cognição, este estudo intenta mostrar que o caráter inerentemente argumentativo que caracteriza a construção dos map...

Indo além dos acidentes e cálculos presentes no Ensino de Radioatividade, propomos um novo olhar ao resgatar a condição da radioatividade como fenômeno natural e presente nas nossas vidas mais do que possamos imaginar. Tal noção foi objeto de uma proposta formativa num curso de Licenciatura em Química numa instituição pública de Pernambuco na forma...

polimetilmetacrilato de metila (PMMA) é um polímero acrílico formado pela união de unidades de metacrilato de metila (MMA). O PMMA tem sido utilizado na área biomédica como implante, sistema de liberação para fármacos e materiais odontológicos. O presente trabalho realizou o monitoramento da polimerização radicalar in situ do PMMA através de uma so...

O presente artigo apresenta a construção e análise de material instrucional potencialmente significativo para a educação Química no Ensino Médio, fundamentado na relação entre a Teoria da Aprendizagem Significativa Crítica e seus princípios com a argumentação em sala de aula. O material construído foi utilizado em uma disciplina da parte diversific...

Commercial Poly(vinyl chloride) (PVC) compounds are based on the combination of the polymer and additives that gives the formulation necessary for the end‐use. In medical‐device applications, PVC may be treated by gamma irradiation in sterilization process. As a consequence of ionization during irradiation, PVC chains undergo simultaneously crossli...

Form‐stable solid‐liquid phase change materials (FSSL‐PCM) are capable of latent heat storage by absorbing thermal energy at constant temperature while undergoing solid‐liquid state transitions. We suggest new nanocomposites based on biodegradable polyesters Poly(ϵ‐caprolactone) (PCL), Poly(3‐hidroxybutyrate) (P‐3‐HB) or their blends with Poly(ethy...

We describe the use of Pachystroma longifolium (Nees) I. M. Johnst, commonly called canxim, as a radiolytic stabilizer of PVC exposed to γ‐irradiation. Results obtained by viscosity analysis shows that ashes from canxim leaves at the concentration of 0.7 wt% provided macromolecular radioprotective action of 88.2% to the PVC. FT‐IR spectra analysis...

Herein, the effect of different post-pressing times and pressure in two cycles of polymerization on the degree of conversion (DC) of thermally activated acrylic resin (TRRA) is analyzed to optimize the polymerization of this material. After post-pressing for 0, 6, or 12 h, polymerization was performed with or without a pressure of 60 psi (0.41 MPa)...

Lignocellulosic biomass is a renewable and abundant resource that is suitable for the production of bio-based materials such as biofuels and chemical products. However, owing to its complex chemical composition, it requires a process that enhances the release of sugars. Pretreatment is an essential stage in increasing the efficiency of enzymatic hy...

The investigation of processes to use oil-rich organic wastes to generate biodiesel is an important research area nowadays. In this respect, quantifying oil/fat and biodiesel with less labor demanding analytical tools such as proton nuclear magnetic resonance (1H NMR) can provide faster and more accurate acquisition of the chemical quality paramete...

Zinc sulfide (ZnS) was synthesized by sonochemical method and nanoparticles with crystallite size around 2 nm were obtained. PVC containing ZnS nanoparticles at concentrations of 0.10; 0.30; 0.50; 0.7 and 1.00 wt% were gamma irradiated (60Co) at room temperature in air. No appreciable decrease in PVC Viscosity-Average Molar Mass (Mv) was observed f...

The poly (vinyl chloride), PVC, undergoes changes in its physicochemical properties when it is exposed to gamma radiation. Thus, the radiolytic stabilization of PVC is one way for obtain a material with radiation resistance. In this work, we studied the coffee grounds oil as PVC radiolytic protection in two systems forms: PVC film and PVC specimen....

Hybrid organic–inorganic materials combine both typical inorganic and organic material properties, allowing them to be applied in a wide range of areas, including radiation-resistant polymers. In this study, Copper sulfide (CuS) is presented as an unprecedented inorganic radiolytic stabilizer for Poly(vinyl chloride). CuS nanoparticles were synthes...

Resumo O ensino de química muitas vezes é guiado pela utilização de fórmulas e esquemas, dada a natureza dos símbolos que permeiam tal disciplina. Nesse cenário, são poucos os estudos que tratam de aspectos ligados ao processo de reflexão usando temas na área de ciências exatas. Assim, fazer parte da formação de indivíduos críticos e reflexivos em...

The aim of this study was to compare the biopharmaceutical characteristics and irritation potentials of microemulsions (MEs) and conventional systems (CSs) containing oil from Syagrus cearensis for topical delivery of Amphotericin B (AmB). Pseudo-ternary phase diagrams were constructed using a water titration method to develop the MEs, and the CSs...

Poly (methyl methacrylate), PMMA, may be used in manufacturing of devices, which are exposed to gamma irradiation. However, the polymer undergoes significant changes in its properties during process and the use of additives is a common form to stabilize the PMMA matrix. In this way, stibnite was synthesized by sonochemical method and the amorphous...

Lead (II) sulfide (PbS) were synthesized by sonochemical method and crystals with cubic structure exhibit aggregated nanoparticles with size in the range of 50-100 nm. Commercial Poly(methyl methacrylate) (PMMA) containing the PbS nanoparticles (PbS-NP) exposed to gamma irradiation were investigated and both the viscosity-average molar mass (Mv) an...

The sterilization by gamma radiation is used as an international standard and its use has grown substantially in national processes. In this review, it is treated the interaction of ionizing radiation with matter and its effects, in addition to various applications of gamma irradiation as an effective tool for sterilization and decontamination of p...

This study aims to investigate the contributions of conceptual maps in the analysis of the construction of knowledge related to the topic Radioactivity in chemistry teaching. Theoretical paradigm of Meaningful Learning from David Ausubel study was utilized with students of high school (third year). This theory includes the learner appropriates the...

Samples of commercial PVC containing a salt mixture of CuCl2/KI (PVC-salt) were investigated. The samples were irradiated with gamma radiation (60Co) at dose 25 kGy. PVC and PVC-salt system showed a decrease in viscosity molar mass values on irradiated samples reflecting the main chain random scissions effect. However the PVC-salt at 0.5 wt% concen...

The refractive index (RI) and Fourier transform infrared (FTIR) spectrum of a poly(vinyl chloride) (PVC)/polystyrene (PS) mixture were measured. The variation of RI with the mixture composition was found to be nonlinear, which indicated the immiscibility of the PVC/PS mixture. This result agrees with results obtained by the FTIR technique, which in...

The ability of Tinuvin 622, a Hindered Amine Stabilizer (HAS), in decreasing of radiation damage to commercial PMMA matrix used in manufacturing of medical supplies was examined. Effects of gamma irradiation in PMMA specimens irradiated at dose range of 10–60 kGy were assessed by comparison of the variation of viscosity average molar mass (Mv) of P...

Commercial polystyrene (PS) has been studied as a modifier for commercial poly(vinyl chloride) (PVC) when it was submitted to gamma irradiation. PVC/PS blends were prepared with 100/0, 95/05 and 90/10 compositions. Results for gamma-irradiated (60Co) blends are reported and changes in viscosity-average molar mass (Mv) were analyzed. The study showe...

Commercial Poly(methyl methacrylate) (PMMA) containing Tinuvin 622, a Hindered Amine Stabilizer (HAS), in 0.3% (wt/wt) concentration was investigated. The samples were irradiated with gamma radiation (60Co) at room temperature in air. The viscosity-average molecular weight (Mv) was analyzed by viscosity technique. Both control PMMA (without HAS) an...

The synthesis of a copolymeric optical matrix from its monomers, acrylic acid and methylmethacrylate, is presented and discussed in this paper. The effect of the acrylic acid concentration has been studied by determining the transmittance of the copolymeric matrix through its ultraviolet spectra (218 to 475 nm). The study shows that at high concent...

An analysis of the knowledge about organics functions as an instrument for polymer learning This work aimed to estimate and use previous knowledge about organic function as an educational tool for polymers science learning. Were surveyed thirty nine freshmen students from a Brazilian public University, four graduate students working in polymer rese...