Obtenção de emulsões asfálticas modificadas utilizando resíduos industriais

The main objective of this research was the development and characterization of conventional and modified cationic asphalt emulsions. The asphalt emulsions were developed by using the Petroleum Asphalt Cement (CAP 50-70) from Fazenda Belém (Petrobras -Aracati-Ce). The first step in this research was the development of the oil phase (asphalt + solvent) and the aqueous phase (water + emulsifying agent + acid + additives), separately. During the experiments for the obtaining of the conventional asphalt emulsion, the concentration of each constituent was evaluated. For the obtaining of the oil phase, kerosene was used as solvent at 15 and 20 wt.%. For the development of the aqueous phase, the emulsifying agent was used at 0.3 and 3.0 wt.%, whereas the acid and the additive were set at 0.3 wt.%. The percentage of asphalt in the asphalt emulsion was varied in 50, 55, and 60 wt.% and the heating temperature was set at 120 °C. The aqueous phase in the asphalt emulsion was varied from 16.4 to 34.1 wt.% and the heating temperature was set at 60 °C. After the obtaining of the oil and the aqueous phases, they were added at a colloidal mill, remaining under constant stirring and heating during 15 minutes. Each asphalt emulsion was evaluated considering: sieve analysis, Saybolt Furol viscosity, pH determination, settlement and storage stability, residue by evaporation, and penetration of residue. After the characterization of conventional emulsions, it was chosen the one that presented all properties in accordance with Brazilian specifications (DNER-EM 369/97). This emulsion was used for the development of all modified asphalt emulsions. Three polymeric industrial residues were used as modifier agents: one from a clothing button industry (cutouts of clothing buttons) and two from a footwear industry (cutouts of sandals and tennis shoes soles), all industries located at Rio Grande do Norte State (Brazil).The polymeric residues were added into the asphalt emulsion (1 to 6 wt.%) and the same characterization rehearsals were accomplished. After characterization, it were developed the cold-mix asphalts. It was used the Marshall mix design. For cold-mix asphalt using the conventional emulsion, it was used 5, 6 and 7 wt.% asphalt emulsion. The conventional mixtures presented stability values according Brazilian specification (DNER-369/97). For mixtures containing asphalt modified emulsions, it was observed that the best results were obtained with emulsions modified by button residue

Dificuldades no processo ensino aprendizagem de trigonometria por meio de atividades

This study analyses the difficulties that teachers of high school face in the process of the teaching of trigonometry through activities in a construtivist focus. It contains a review of some publications and dissertations related with the study of trigonometry elaborated in the last years by several authors. It resorts to the study of teaching engineering as an instrument used in the research. It also presents a set of activities which will serve as sample to other teachers of mathematics; and points ways for the overcome of the difficulties found

Ética da alimentação: porque devemos, segundo Kant, escolher uma alimentação adequada e saudável

This thesis proposes the adoption of a practical and philosophic approach to the discussion about what should be a healthy food, in view of the actual problems concerning this subject (from famine to obesity), which affect food and nutritional security and constitute target of many official policies. In order to handle this task, this work resorts to ethic, pedagogical and anthropological concepts inherent to Immanuel Kant’s philosophy, as valuable contributions to the practice of the professional nutritionist committed to the support and accomplishment of the human right to adequate nutrition (DHAA). Under this assumption, it intends to surpass the prevailing idea inside the social programs and policies favoring the utilitarian argument. It considers rather that a healthy food is also a duty of virtue, according to the Kantian duties to one-self. The liberation of transgenic seeds in Brazil comes up as an example of the violation of the right to food security and affects it negatively, resulting from the conflict between politics and moral faced by the Brazilian government. This paper concludes that DHAA realization requires not only a committed state, but also committed citizens and suggests that Kant’s philosophy should offer important contributions to supporting the practice of the professional nutritionist, awarding him the necessary information about this matter.

Ética da alimentação: porque devemos, segundo Kant, escolher uma alimentação adequada e saudável

This thesis proposes the adoption of a practical and philosophic approach to the discussion about what should be a healthy food, in view of the actual problems concerning this subject (from famine to obesity), which affect food and nutritional security and constitute target of many official policies. In order to handle this task, this work resorts to ethic, pedagogical and anthropological concepts inherent to Immanuel Kant’s philosophy, as valuable contributions to the practice of the professional nutritionist committed to the support and accomplishment of the human right to adequate nutrition (DHAA). Under this assumption, it intends to surpass the prevailing idea inside the social programs and policies favoring the utilitarian argument. It considers rather that a healthy food is also a duty of virtue, according to the Kantian duties to one-self. The liberation of transgenic seeds in Brazil comes up as an example of the violation of the right to food security and affects it negatively, resulting from the conflict between politics and moral faced by the Brazilian government. This paper concludes that DHAA realization requires not only a committed state, but also committed citizens and suggests that Kant’s philosophy should offer important contributions to supporting the practice of the professional nutritionist, awarding him the necessary information about this matter.