Propriedades física de molécilas orgânicas e compostos do tipo perovskita CdSiO3 e CaPbO3

In the first part of this work our concern was to investigate the thermal effects in organic crystals using the theory of the polarons. To analyse such effect, we used the Fröhlich s Hamiltonian, that describes the dynamics of the polarons, using a treatment based on the quantum mechanics, to elucidate the electron-phonon interaction. Many are the forms to analyzing the polaronic phenomenon. However, the measure of the dielectric function can supply important information about the small polarons hopping process. Besides, the dielectric function measures the answer to an applied external electric field, and it is an important tool for the understanding of the many-body effects in the normal state of a polaronic system. We calculate the dielectric function and its dependence on temperature using the Hartree-Fock decoupling method. The dieletric function s dependence on the temperature is depicted by through a 3D graph. We also analyzed the so called Arrhenius resistivity, as a functionof the temperature, which is an important tool to characterize the conductivity of an organic molecule. In the second part we analyzed two perovskita type crystalline oxides, namely the cadmium silicate triclinic (CdSiO3) and the calcium plumbate orthorhombic (CaPbO3), respectively. These materials are normally denominated ABO3 and they have been especially investigated for displaying ferroelectric, piezoelectric, dielectrics, semiconductors and superconductors properties. We found our results through ab initio method within the functional density theory (DFT) in the GGA-PBE and LDA-CAPZ approximations. After the geometry optimization for the two structure using the in two approximations, we found the structure parameters and compared them with the experimental data. We still determined further the angles of connection for the two analyzed cases. Soon after the convergence of the energy, we determined their band structures, fundamental information to characterize the nature of the material, as well as their dielectrics functions, optical absorption, partial density of states and effective masses of electrons and holes

A aproximação entre educação escolar e trabalho: a experiência da Casa do Menor Trabalhador

It aims to consider the possible relationship between formal school education and work, from the experience of the State School House of the Minor Worker CMT of Natal-RN in this first decade of the 21st century. In this institution, children and adolescents are enrolled in the Fundamental Teaching sponsored by the State Public System studying the regular curriculum contents defined for this level of teaching, and in the opposite shift they take part in career workshops which are kept by members of a religious congregation. CMT has had as its object, since its foundation, to take children and adolescents from the streets and to provide them with a full time education associating basic education and training/qualification for the job market. In our research, we tried to learn a little bit of the expectations, concerns and knowledge of the young participants of two workshops: carpentry and bakery, so that we could gain sufficient understanding of the learning process of these youths, while still keeping an approximation with the reality of the aforementioned subjects. It was possible for us to conduct a description of the contexts and of characteristics of the subjects which make up CMT, capturing concrete aspects and aspects of the thoughts of students, teachers, instructors and coordinators. The main point of our research was: how does the approximation between formal school education and work take place in the House of the Minor Worker? To search for possible answers we have made use of basic techniques for the data construction - questionnaire, observation, conversation groups, assessment drills which allowed an approximation and a good dialogue with the participants. We also discussed the job world in the context of the capitalist exploration, from the contributions of Mèszáros (2005), Frigotto (1989); (1993); (1999); (2002); Ferretti (1994); (2004); Kuenzer (1989); (1997), in order to understand the skills demanded of the worker and the necessity of an education which allows the professional qualification of youths eager to enter the job market, through the first job. In this perspective, the study that we have systematized here aims to show the relevance of an education which manages to take a firm and conscientious stand in connection with the hegemonic capitalist project and to provide for a humane, ethical, responsible, critical and civic background