Síntese e caracterização de TaC e óxido misto de tântalo e cobre nanoestruturados a partir do precursor oxálico de tântalo através de reações gás-sólido e sólido-sólido a baixa temperatura

The research and development of nanostructured materials have been growing significantly in the last years. These materials have properties that were significantly modified as compared to conventional materials due to the extremely small dimensions of the crystallites. The tantalum carbide (TaC) is an extremely hard material that has high hardness, high melting point, high chemical stability, good resistance to chemical attack and thermal shock and excellent resistance to oxidation and corrosion. The Compounds of Tantalum impregnated with copper also have excellent dielectric and magnetic properties. Therefore, this study aimed to obtain TaC and mixed tantalum oxide and nanostructured copper from the precursor of tris (oxalate) hydrate ammonium oxitantalato, through gas-solid reaction and solid-solid respectively at low temperature (1000 ° C) and short reaction time. The materials obtained were characterized by X-ray diffraction (XRD), Rietveld refinement, Scanning Electron Microscopy (SEM), Spectroscopy X-Ray Fluorescence (XRF), infrared spectroscopy (IR), thermogravimetric (TG), thermal analysis (DTA) and BET. Through the XRD analyses and the Reitiveld refinement of the TaC with S = 1.1584, we observed the formation of pure tantalum carbide and cubic structure with average crystallite size on the order of 12.5 nanometers. From the synthesis made of mixed oxide of tantalum and copper were formed two distinct phases: CuTa10O26 and Ta2O5, although the latter has been formed in lesser amounts

Desenvolvimento de um sistema misto de pasta à base de geopolímero e cimento portland para correção de perda de circulação

The materials engineering includes processes and products involving several areas of engineering, allowing them to prepare materials that fulfill the needs of various new products. In this case, this work aims to study a system composed of cement paste and geopolymers, which can contribute to solving an engineering problem that directly involves the exploitation of oil wells subject to loss of circulation. To correct it, has been already proposed the use of granular materials, fibers, reducing the drilling fluid or cement paste density and even surface and downhole mixed systems. In this work, we proposed the development of a slurry mixed system, the first was a cement-based slurry and the second a geopolymer-based slurry. The cement-based slurry was formulated with low density and extenders, 12.0 ppg (1.438 g/cm ³), showing great thixotropic characteristics. It was added nano silica at concentrations of 0.5, 1.0 and 1.5 gps (66.88, 133.76 and 200.64 L/m3) and CaCl2 at concentrations of 0.5, 1, 0 and 1.5%. The second system is a geopolymer-based paste formulated from molar ratios of 3.5 (nSiO2/nAl2O3), 0.27 (nK2O/nSiO2), 1.07 (nK2O/nAl2O3) and 13.99 (nH2O/nK2O). Finally, we performed a mixture of these two systems, for their application for correction of circulation lost. To characterize the raw materials, XRD, XRF, FTIR analysis and titration were performed. The both systems were characterized in tests based on API RP10B. Compressive strength tests were conducted after curing for 24 hours, 7 and 28 days at 58 °C on the cement-based system and the geopolymer-based system. From the mixtures have been performed mixability tests and micro structural characterizations (XRD, SEM and TG). The results showed that the nano silica, when combined with CaCl2 modified the rheological properties of the cement slurry and from the concentration of 1.5 gpc (200.64 L / m³) it was possible to obtain stable systems. The system mixture caused a change in the microstructure of the material by favoring the rate of geopolymer formation to hinder the C3S phase hydration, thus, the production of CSH phases and Portlandite were harmed. Through the mixability tests it can be concluded that the system, due to reduced setting time of the mixture, can be applied to plug lost circulation zones when mixed downhole

Produção de bioetanol por uma cultura mista de leveduras a partir de um substrato misto de alfarroba e soro de queijo

Dissertação de Mestrado, Engenharia Biológica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014

A Relação professor-aluno e a afirmação do discente como sujeito do processo projetual: um estudo exploratório sobre a produção do trabalho final de graduação em arquitetura e urbanismo na UFC e na UFRN

This work deals with teacher-student relationship (TSR), held in a very special moment: the semester of graduation of architecture and urbanism, where students prepare the final work called Graduation Final Work (GFW). That is the last stage to obtain the title of architect and urban planner in Brazil. The text discusses this problem in several ways, emphasing the relationship between graduated student and his/her mentors into the consolidation process of the student as an actor of the planning process, here defined as "autonomy". The work is focused on understanding the TSR in order to elucidate its importance for improvement of teaching bases on development of the GFW, more than the relation between curriculum and institution. Related with the exploratory characteristic of this master thesis, methodologically, the field work happened through: (i) observation of mentorship guidance, (ii) interviews, and (iii) application of questionnaires to teachers and students. Participated 10 pairs of student and mentors of two federal university of Northeast: 05 pairs of the Federal University of Ceará (UFC) and 05 pairs of the Federal University of Rio Grande do Norte (UFRN). The results presented the development of the GFW as a difficult process / fearful for students, highlighting the main problem situations: the difficulty in choosing the theme, the super-sizing of the process, students' insecurities, and parental relationship with the supervisor process. Summing up, the work indicates that the students has a limited autonomy on the GFW process, which calls for a revision in order to promote the consolidation of the student autonomy, which must be observed for some positions recognition of the role of each actor in the process of orientation

Análise de métodos de predição de conforto térmico de habitação em clima quente-úmido com condicionamento passivo

The assessment of building thermal performance is often carried out using HVAC energy consumption data, when available, or thermal comfort variables measurements, for free-running buildings. Both types of data can be determined by monitoring or computer simulation. The assessment based on thermal comfort variables is the most complex because it depends on the determination of the thermal comfort zone. For these reasons, this master thesis explores methods of building thermal performance assessment using variables of thermal comfort simulated by DesignBuilder software. The main objective is to contribute to the development of methods to support architectural decisions during the design process, and energy and sustainable rating systems. The research method consists on selecting thermal comfort methods, modeling them in electronic sheets with output charts developed to optimize the analyses, which are used to assess the simulation results of low cost house configurations. The house models consist in a base case, which are already built, and changes in thermal transmittance, absorptance, and shading. The simulation results are assessed using each thermal comfort method, to identify the sensitivity of them. The final results show the limitations of the methods, the importance of a method that considers thermal radiance and wind speed, and the contribution of the chart proposed

O novo Código florestal e a regularização do passivo ambiental dos imóveis rurais : o caso de Querência

Dissertação (mestrado)—Universidade de Brasília, Centro de Desenvolvimento Sustentável, Programa de Pós-Graduação em Desenvolvimento Sustentável, 2016.

Caracterização de um ecossistema sujeito a desflorestação e conversão do uso do solo na região de Quibala, Angola

Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia - UL

Passivo ambiental: estudo de caso

Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Contabilidade e Finanças

Design gráfico da pluma de contaminação por compostos orgânicos voláteiss utilizando software CAD na investigação de passivo ambiental em um posto revendedor de combustíveis em Natal/RN

Among the potentially polluting economic activities that compromise the quality of groundwater are the gas stations. The city of Natal has about 120 gas stations, of which only has an environmental license for operation. Discontinuities in the offices were notified by the Public Ministry of Rio Grande do Norte to carry out the environmental adaptations, among which is the investigation of environmental liabilities. The preliminary and confirmatory stages of this investigation consisted in the evaluation of soil gas surveys with two confirmatory chemical analysis of BTEX, PAH and TPH. To get a good evaluation and interpretation of results obtained in the field, it became necessary three-dimensional representation of them. We used a CAD software to graph the equipment installed in a retail service station fuel in Natal, as well as the plumes of contamination by volatile organic compounds. The tool was concluded that contamination is not located in the current system of underground storage of fuel development, but reflects the historical past in which tanks were removed not tight gasoline and diesel

Evolución del impuesto al valor agregado (IVA)

Bogotá (Colombia) : Universidad de La Salle. Facultad de Ciencias Administrativas y Contables. Programa de Contaduría Pública

Las entidades del tercer sector como prestadores de servicios asistenciales en el IVA: exenciones y tipos reducidos

El estudio trata de dar respuesta a las incertidumbres que se derivan de la actual regulación del IVA en materia de asistencia social, un sector de actividad de gran interés para las entidades de la economía social (Tercer Sector) y, en particular, para las cooperativas. Tras unas consideraciones generales sobre el funcionamiento del impuesto en este contexto, se analizan las exenciones y tipos reducidos aplicables a las prestaciones asistenciales.

O desejo no feminino

Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção de grau de Mestre na especialidade de Psicologia Clínica

Diagnóstico do passivo ambiental no projeto de assentamento Luis Lopes Sobrinho, São Francisco do Pará-PA.

A região nordeste do Estado do Pará constitui uma das mais antigas áreas de ocupação na região amazônica que, por conseguinte, necessita de estudos para mitigar os seus impactos ambientais. Neste trabalho é avaliada espacialmente a situação das áreas com restrições legais ao uso do solo (Áreas de Preservação Permanente e Áreas de Reserva Legal) no Projeto de Assentamento Luis Lopes Sobrinho, a partir de ferramentas de geotecnologias. Foi verificado que apesar da maior parte das APPs estarem preservadas, existe uma parcela a ser recuperada de 22,23 ha (13,58% do total). No que tange a ARL, o total de área de tipologia florestal necessária à averbação possui um deficit de 221,33 ha (10,14% do total). Ainda que a área de APP preservada fosse contabilizada para a averbação da ARL, não seria possível atingir os 50% do total da propriedade (2.182,60 ha) previstos em lei.

O VALOR DA APREENSÃO DA PAISAGEM DO PARQUE NACIONAL DA CHAPADA DIAMANTINA/BA CENTRADA NO SUJEITO E NO ESPAÇO

O presente artigo estima o valor econômico atribuído pelos Agentes/Atores Sociais aos Municípios de Lençóis, Mucugê, Andaraí, Palmeiras e Ibicoara,  com uso do Método de Avaliação Contingente, a partir da valoração da paisagem centrada no sujeito e no espaço. A atividade turística da região está centrada na singularidade do local, cuja variada de recursos naturais expressam o mais belo cenário paisagístico montanhoso da Bahia, formado por um conjunto de vales e serras, riqueza arquitetônica das cidades históricas, vegetação exótica, quedas d‘água contando com a presença constante de cascatas e outros atrativos naturais. Os entrevistados foram questionados sobre as suas disposições a pagar, através do DAP, constituído de perguntas estruturadas, no formato dicotômico para responder, (Sim / Não). Constatou-se na pesquisa empírica a dificuldade em induzir os indivíduos a revelaram sua verdadeira disposição de pagar pelo patrimônio ambiental, em razão da responsabilidade individual do entrevistado, frente à questão e a possibilidade de aproveitamento coletivo advindo da conservação ambiental.