Estudo do equilíbrio químico dos ácidos naftênicos através da técnica de titulação potenciométrica

TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Físicas e Matemáticas. Curso de Química.O aumento da oferta de petróleo com alto conteúdo de impurezas torna o processamento oneroso devido à corrosão nos condensadores de topo. É conhecido que a combinação dos ácidos naftênicos e sais cloreto de cálcio e magnésio causam sérios problemas nas operações de refino. Os ácidos naftênicos estimulam a produção de cloretos que ao ser exposto ao calor e água formam acido clorídrico como um produto paralelo causando corrosão severa nos equipamentos de topo. Nossos resultados indicaram que o ácido naftênico não contribui na hidrolise dos íons metálicos mas age cooperativamente coordenando-os e consequentemente liberando prótons para formar o acido clorídrico. Nesse trabalho avaliou-se a coordenação dos ácidos naftênicos com íons metálicos: Mg(II) e Ca(II) para o melhor entendimento do mecanismo da ação corrosiva pela produção de HCl. Para realizar este estudo e avaliar precisamente a ação de diversos íons metálicos, primeiramente são requeridos os estudos de equilíbrio ácido-base e o equilíbrio que envolve a complexação. Na primeira parte deste trabalho, mostramos os resultados da titulação potenciométrica do ácido naftênico, derivado do petróleo, com os íons metálicos Mg(II) e Ca(II), em sistema água/etanol. A coordenação do ácido naftênico com os referidos metais foi confirmada por análise de infravermelho. Observou-se a formação de três espécies ML, ML2 e ML3, onde M é o íon metálico e L representa uma molécula de ácido naftênico. Na distribuição das espécies nos sistemas Ca(II) e Mg(II), observou-se a predominância da espécie ML3 com constantes de equilíbrio iguais a 11,20 e 11,87 respectivamente. O estudo foi fundamental para mostrar que os ácidos naftênicos complexão com os metais estudados, resultando na liberação de prótons e conseqüente aumento de HCl

Preserving Fragile History: Assessing the Feasibility of Segmenting Digitized Historical Documents with Modulation Depth Analysis

Historical documents are often severely damaged, making it impossible to open them manually without causing further damage. To address this challenge, computed tomography (CT) has emerged as a non-destructive method to explore the inside in a different way. However, the use of ionising radiation in CT scanning raises concerns about its impact on fragile historical documents. This study presents a methodology that uses a test object to conduct preliminary investigations to evaluate the capability of a CT scanner for digital preservation of historical documents. By assessing the feasibility and determining the setting parameters in advance, the X-ray exposure to historical documents can be minimised. For this purpose, a large dataset of inter-page distances was obtained from CT scans of a specially developed test object. The results obtained show a consistent correlation between the page-to-page distances and the derived modulation depths. This method offers great potential for assessing the separability of the pages of historical documents even before they are exposed to radiation for digitisation. Overall, this study helps to reduce the impact of X-ray radiation on sensitive historical documents during digitisation using CT, with the aim of preserving this fragile cultural heritage for future generations.Deutsche Forschungsgemeinschaf

Mentoring New Faculty: An Appreciative Approach

During this period of dramatic social and institutional change in higher education, positive induction and ongoing support for early-career and faculty members new to the campus community is essential. Disparities remain in the recruitment, development, retention, and promotion of diverse faculty, in large part because of the lack of mentoring. The purpose of this article is to enhance approaches for supporting early-career and otherwise new faculty members. Based upon the principles and processes of Appreciative Inquiry, the Appreciative Mentoring Model is presented. Each of the Appreciative Inquiry “D-phases” is described in detail together with research-based best practices that can be employed in mentoring. Prompts, questions, and specific examples designed to support the growing need for a more collaborative, fluid, dynamic, and transformative approach to mentoring are provided.

Parent-Child Talk about Early Numeracy

The goal of the study was to examine how the type of informal number activity in which parents and their preschoolers engage and parents’ math-related beliefs relate to parent-child exploration of an advanced early number concept. Parents and their preschoolers (n = 46) engaged in a videotaped play session and parents were surveyed about their math-related beliefs. The findings indicate that the type of informal number activity that parents chose to play with their children predicted how frequently they explored an advanced early number concept with them. Additionally, some but not all parents’ math-related beliefs were related to parent-child number talk. These results suggest that identifying games that facilitate specific number concepts may be a good way for researchers to help parents and children explore more advanced early number concepts frequently. The results also highlight the need for additional research on the role of parents’ math-related beliefs in their support of their children’s early learning and school readiness

Connecting the dots: Examining the role of parental beliefs and preschoolers’ affect and engagement in predicting parent-child number exploration during a meaningful math experience

The current study examined the frequency and quality of how 3- to 4-year-old children and their parents explore the relations between symbolic and non-symbolic quantities in the context of a playful math experience, as well as the role of both parent and child factors in this exploration. Preschool children’s numerical knowledge was assessed while parents completed a survey about the number-related experiences they share with their children at home, and their math-related beliefs. Parent-child dyads were then videotaped playing a modified version of the card game War. Results suggest that parents and children explored quantity explicitly on only half of the cards and card pairs played, and dyads of young children and those with lower number knowledge tended to be most explicit in their quantity exploration. Dyads with older children, on the other hand, often completed their turns without discussing the numbers at all, likely because they were knowledgeable enough about numbers that they could move through the game with ease. However, when dyads did explore the quantities explicitly, they focused on identifying numbers symbolically, used non-symbolic card information interchangeably with symbolic information to make the quantity comparison judgments, and in some instances, emphasized the connection between the symbolic and non-symbolic number representations on the cards. Parents reported that math experiences such as card game play and quantity comparison occurred relatively infrequently at home compared to activities geared towards more foundational practice of number, such as counting out loud and naming numbers. However, parental beliefs were important in predicting both the frequency of at-home math engagement as well as the quality of these experiences. In particular, parents’ specific beliefs about their children’s abilities and interests were associated with the frequency of home math activities, while parents’ math-related ability beliefs and values along with children’s engagement in the card game were associated with the quality of dyads’ number exploration during the card game. Taken together, these findings suggest that card games can be an engaging context for parent-preschooler exploration of numbers in multiple representations, and suggests that parents’ beliefs and children’s level of engagement are important predictors of this exploration