Investigação experimental das propriedades termofísicas e da convecção forçada de nanofluido de grafeno

This work presents an experimental investigation of thermal hydraulic performance of the nanofluid composed by graphene nanoparticles dispersed in a mixture of water and ethylene glycol at a ratio of 70:30% by volume. The tests were carried out under forced convection inside a circular tube with uniform heat flux on the wall for the laminar-turbulent transition regime. The mass flow rate ranged from 40 to 70 g/s corresponding to Reynolds numbers between 3000 and 7500. The heat flux was maintained constant at values of 11, 16 and 21 kW/m², as well as the inlet temperature of 15, 20 and 25°C. Three samples were produced with the nanofluid volumetric concentration of 0.05%, 0.10% and 0.15%. Thermophysical properties were experimentaly measured for all samples that were critically compared and discussed with theoretical models most commonly used in the literature. Initially, experiments with distilled water confirmed the validity of the experimental equipment for the thermo-hydraulic tests. Therefore, nanofluid samples that showed the highest thermal conductivity, corresponding to the volumetric concentrations of 0.15% and 0.10%, were subjected to the tests. The thermal-hydraulic performance for both samples was unsatisfactory. The heat transfer coefficients for convection of nanofluids reduced 21% in average, for the sample with = 0.15% and 26% and for =0.10%. The pressure drop of the samples was higher than the base fluid. Finally, the pressure drop and heat transfer coefficient by convection of both samples were also compared to theoretical models. The models used for pressure drop showed an excellent agreement with experimental results, which is remarkable considering the transitional flow.

O programa institucional de bolsa de iniciação à docência PIBID na formação inicial de professores de matemática

This research sought to understand the space training provided by Institutional Scholarship Program Initiation of Teaching to a group of students of Degree in Mathematics that had activities developed in the same public school. The goal is to qualify them for teaching practice for these basic institutions. We decided to conduct a qualitative study of type ethnographic case study. For a year and a half while we were at the meetings and activities of the Group, we did what we call as a participant observation. To obtain the data, we used different survey instruments: the researcher\'s field notes through his observation of everyday life of the group, photographs and filming of the activities, document analysis and database produced, physically and digitally, in addition to questionnaires and interviews with records written, which complemented each other and helped establish a triangulation of information collected. We analyze the trajectory of the group on three axes: on the first, we present and understand the paths taken by the Group in the process of setting up training spaces, and production of their professional training, in the second, we analyze how the space of PIBID is being integrated with others spaces of formations in the educational institution of the degree course in mathematics and, in the third axis, we understand the process of knowledge production of that group. The trajectory taken by the group was marked by a process of reflection and discussion systematic and collective, which favored the pursuit for be a better professional and also confirmed a possible path to be followed in initial teacher education.

Formação inicial do professor de matemática com uso de tecnologias da informação e comunicação no contexto da escola pública

This paper intends to analyze which contribution for teachers formative training the participation on extension projects can bring to the bachelors in Mathematics teaching. The research was conducted during the developing of a Project from the Program of Extension - Programa de Extensão UFU/Comunidade (PEIC) in a municipal school located in a country zone from Uberlândia-MG. The research was constituted by a series of activities with students from the ninth year of the Fundamental Education, Middle School. The main focus is the work developed by two bachelors of Mathemactics teaching from the Federal University from Uberlândia who were part of the PEIC team. This present research intends to answer the following question: How the extension project “Information technology and communication on Mathematics problem resolution in country zone schools” has contribited to reinforce and to (re)criate the fomative experiences of students from the Mathematics teaching course who have developed such project? The presente study is from a qualitative nature and has made use of the partaker searching methodology. The presente paper was organized in three chapters. On chapter I evidence is given to theoretical discussion made, having as main references the works of Larrosa, Ponte e Shön. Chapter II brings the description of the three activities that were developed and aplied during the PEIC Project, which are: Problems in the Park, Inaccessible Hight and Lili Game. On chapter III, the data analysis is presented. The data was obtained through instruments of registration such as: camera recording, photografic material, meetings reports, field notes, surveys and semi-structured interviews. The initial hypothesis aim is on the fact that the participation on extention projects during the graduation course can bring rich contribution for the teachers to be, since it’s going to provide the knowledge and chalenge close to the one from the future profession. With the analysis of the obtained results from the colected data, it was possible to conclude that the PEIC has provided the bachelors in Mathematics teching the opportunity of recreate and potenciate their formative experiences. Such opportunity happened in situations that involved, for example, planning makings, development of colective work, softwares usage, different school spaces and the direct interaction with school bureaucracy. Beyond that, it was possible to work with the cocepts of reflection in action in a way to contribute to the professional development of the future Mathematics teachers. Thereby, in our final considerations, is possible to conclude that extension projects performed during the graduation course can bring great contributions to the professional formation of the bachelors in Mathematics teaching, among them we highlight the potentiation of the previous formative experiences and the development of colective work and behavior related to a reflexive teacher.