Impregnation of activated carbons for pre- and post-combustion CO2 capture in a fixed bed pressure swing adsorption reactor: a modelling and experimental comparison

The mitigation of greenhouse gases, such as carbon dioxide, is of timely concern in the energy sector, requiring new techniques and process options to treat acidic gases and develop solutions for capture and reuse. Solid adsorbents are potentially viable for application as the next generation carbon capture technology. Activated Carbon Norit® RB1 and Cabot Norit® R2030 were selected for this study, owing to their potentially high adsorption rates and affinity with carbon dioxide molecules. The purpose of thesis was to modify the adsorbent using chemical and amine solutions via an impregnation process to provide high adsorption capacity and performance, focusing on surface area modification and attachment of primary amine groups to improve the solid/gas interaction. Diverse characterisation techniques were used to examine and explore the essential properties and parameters of the modified adsorbents developed. Specifically, scanning electron microscopy (SEM) was used to investigate the surface morphology, thermogravimetric analysis (TGA) was applied to test the adsorption capacity with a pure CO2 flow, a high-pressure volumetric analyser (HPVA) was used to measure the gas volume adsorbed at the pre-combustion condition, producing adsorption-desorption isotherms under nitrogen and carbon dioxide binary mixtures, and the textural properties were determined by Brunauer-Emmett-Teller (BET) analysis, allowing comparison of the pore size and the volume adsorbed per sample. The dynamic adsorption behaviour of the activated carbons (ACs) was studied in a fixed bed reactor using a carbon dioxide concentration range of 10–50% combined with a nitrogen flow. The original and modified adsorbents were tested under pre and post-combustion conditions, with the highest uptake of carbon dioxide found to be for MEA+MDEA+AMP Norit® RB1 AC II under pre-combutions and MEA (20%) Norit® RB1 AC under post-combustion conditions. The introduction of amine groups into the sample lead to the enhancement of chemisorption, while the treatment with KOH modified the surface area of the adsorbents, thereby improving uptake behaviour. Additionally, a Pressure Swing Adsorption (PSA) model using a fixed bed reactor was developed for carbon dioxide capture at pre-combustion conditions (25oC and 25 bar) using gPROMS® ModelBuilder software [version 4.1; developed by Process System Enterprise, PSE]. A parameter estimation was executed using similar conditions as applied in the fixed bed reactor rig at the laboratory scale. Nitrogen and carbon dioxide were applied to this model taking into account the physical behaviour of the PSA unit. The estimations demonstrated an excellent approximation to the experimental breakthrough curve for both adsorbents, which also validated the model supported by the sum of squared residuals (SSR) values. Furthermore, the parameter estimation confirmed the novelty of the two amine modified adsorbents for pre-combustion carbon dioxide adsorption, due to their high potential to capture the desired gas in a binary mixture in the PSA fixed bed reactor process

In vitro rearing of stingless bee queens and their acceptance rate into colonies

International audienceAbstractThe in vitro rearing of queen bees can improve the management and conservation of pollinator insects. Here, we have developed an in vitro queen-rearing protocol for Plebeia droryana (Apidae, Meliponini). Firstly, we evaluated the amount of food offered naturally to P. droryana queen larvae. After, we grafted P. droryana larvae onto acrylic plates which were kept in constant darkness at 25 °C and different relative humidity along larval development. We also compared intertegular distance of P. droryana queens reared in vitro and naturally. We then tested whether queens reared in vitro would be accepted into new colonies with older and/ or callow workers. We found that P. droryana larvae developed into queens if fed with 66 μL of larval food. The survival rate of P. droryana queens was > 75 %. The queens reared in vitro are similar in size to naturally produced ones. Finally, colonies only containing callow workers are more likely to accept queens reared in vitro. This queen-rearing technique may improve beekeeping practices in the Neotropical Region

With how many films can we talk about children? Childhood representational plurality in cinema

Este artigo apresenta um recorte descritivo dos dados de uma pesquisa de doutorado realizada entre 2017 e 2021, cuja ênfase envolveu problematizar a experiência formativa, pedagógica e estética com filmes no contexto acadêmico, mais particularmente no curso de pedagogia. Ao salientar a pluralidade representacional das crianças por meio dos filmes, a partir de uma revisão filmográfica, ou do estado da arte fílmica, e com base nos relatos dos professores participantes do estudo, o objetivo deste texto é refletir sobre a quantidade significativa de curtas, médias e longas-metragens que representam as crianças em suas distintas narrativas. Em relação aos métodos utilizados, privilegiamos no trabalho uma conjunção metodológica interdisciplinar e multirreferencial, com base na Grounded Theory e na bricolagem científica, respaldada pela fenomenologia-hermenêutica. Evidenciamos um total de duzentas e quatro (204) obras cinematográficas entre as publicações analisadas – os dados referem-se a teses, dissertações e artigos científicos –, resultante de buscas no banco de teses e dissertações de bibliotecas digitais e em plataformas de periódicos. Entre os filmes descritos pelos docentes, contabilizamos trinta (30) produções. Consideramos, diante dessa quantidade de obras, que os filmes fazem parte do processo formativo dos estudantes e permitem outras leituras sobre as crianças e infâncias no contexto contemporâneo, o que revela sua relevância como fonte e referência no processo formativo.This article presents part of the descriptive data about a doctoral study held between 2017 and 2021. The study problematized the formative, pedagogical, and aesthetic experience with films in an undergraduate Pedagogy degree. By highlighting children’s representational plurality through films, from a filmography review or film state of the art, this text aims to reflect on the significant amount of short, middle, and feature films that portray children in their different narratives. Regarding the methods used, we privileged the work in an interdisciplinary and multi-referential methodological conjunction based on Grounded Theory and scientific bricolage, backed by hermeneutic phenomenology. We point out 204 cinematographic works - from data on theses, dissertations, and scientific articles – from searches in theses and dissertations databases in digital libraries and journal platforms. The professors interviewed accounted for thirty productions. Faced with this number of works, we believe that films are part of students’ formative process and allow other interpretations of children and childhoods nowadays, revealing their relevance as a source and reference in the formative process

A High-Precision and Low-Cost Dew Point Equipment with Fuzzy Control System

The control of environmental conditions in some sectors of the industry is essential since the variation of these parameters can influence the quality of the manufactured product. For this, it is necessary to use measuring equipment with high precision, and when referring to the measurement of relative humidity, the dew point meter is indispensable. The chilled mirror method for measure °Cdp is the one of the most accurate that exists in the market, but these devices typically are high cost, hampering access to small businesses. The chilled mirror method basically consists of a PID (Proportional Integral Derivative) control of the temperature of a Peltier module based on the reading of the light intensity generated from the reflection of a light source. In this context, the proposal of this work is to develop a high precision and low cost device, operating in the range of -20 to 20°Cdp, replacing the traditional PID control by a Fuzzy control system, providing better accuracy in control, thus making a viable product mainly for small and medium-sized companies. The results presented show the feasibility of the proposal of this work, obtaining 98.9% accurate readings when compared with a reference equipment, and a maximum deviation observed was of 0.02°Cdp, thus proving its precision. Another point to note is the low cost of the equipment, approximately US$ 120.00, thus reaching the proposed objective

A Formação didático-pedagógica do docente de matemática

This article discusses the didactic-pedagogical training of future Mathematics teachers from an exploratory descriptive perspective, highlighting the importance of specific and pedagogical disciplines regardless of the teaching method. It is considered that recent changes in Basic Education in Brazil present significant challenges, such as the need for an improved understanding of the student, the educator's role, and new teaching and assessment approaches. These changes require a reevaluation of traditional mathematical concepts and procedures, aiming for a critical and contextual understanding of Mathematics as a social practice. The article argues that the current educational scenario demands competencies from teachers that are not being sufficiently developed in their training, pointing to the importance of a theoretical and practical foundation that meets the needs of professional knowledge in the field of Mathematics Education.Este artigo aborda a formação didático-pedagógica de futuros professores de Matemática através de uma perspectiva descritiva exploratória, destacando a relevância das disciplinas específicas e pedagógicas independentemente do método de ensino. Considera-se que as recentes mudanças na Educação Básica no Brasil trazem desafios significativos, como a necessidade de uma compreensão aprimorada sobre o aluno, o próprio papel do educador e novas abordagens de ensino e avaliação. Tais mudanças demandam uma reavaliação dos conceitos e procedimentos matemáticos tradicionais, visando uma compreensão crítica e contextualizada da Matemática como prática social. O artigo argumenta que o atual cenário educacional exige dos professores competências que não estão sendo suficientemente desenvolvidas em sua formação, apontando para a importância de uma base teórica e prática que atenda às necessidades do conhecimento profissional na área de Educação Matemática

Magnetic Properties of the Metamagnet Ising Model in a three-dimensional Lattice in a Random and Uniform Field

By employing the Monte Carlo technique we study the behavior of Metamagnet Ising Model in a random field. The phase diagram is obtained by using the algorithm of Glaubr in a cubic lattice of linear size $L$ with values ranging from 16 to 42 and with periodic boundary conditions.Comment: 4 pages, 6 figure