Estudo da sinterização de cavacos de aço ferritico

This research studies the sintering of ferritic steel chips from the machining process. Were sintered metal powder obtained from machining process chips for face milling of a ferritic steel. The chip was produced by machining and characterized by SEM and EDS, and underwent a process of high energy mill powder characterized also by SEM and EDS. Were constructed three types of matrixes for uniaxial compression (relation l / d greater than 2.5). The differences in the design of the matrixes were essentially in the direction of load application, which for cylindrical case axial direction, while for the rectangular arrays, the longer side. Two samples were compressed with different geometries, a cylindrical and rectangular with the same compaction pressure of 700 MPa. The samples were sintered in a vacuum resistive furnace, heating rate 20 °C / min., isotherm 1300 °C for 60 minutes, and cooling rate of 25 °C / min to room temperature. The starting material of the rectangular sample was further annealed up to temperature of 800 ° C for 30 min. Sintered samples were characterized by scanning electron microscopy, optical microscopy and EDS. The sample compressed in the cylindrical matrix did not show a regular density reflecting in the sintered microstructure revealed by the irregular geometry of the pores, characterizing that the sintering was not complete, reaching only the second phase. As for the specimen compacted in the rectangular array, the analysis performed by scanning electron microscopy, optical microscopy and EDS indicate a good densification, and homogeneous microstructure in their full extent. Additionally, the EDS analyzes indicate no significant changes in chemical composition in the process steps. Therefore, it is concluded that recycling of chips, from the processed ferritic steel is feasible by the powder metallurgy. It makes possible rationalize raw material and energy by manufacture of known properties components from chips generated by the machining process, being benefits to the environment

Estudo da adição do resíduo proveniente da extração de minério de ferro em argilas do Rio Grande do Norte

The mining industry is responsible for the generation of waste from their natural process of extraction. The mining impacts in urban areas are of special importance due to the high urban occupation, which are exacerbated due to the proximity of the mined areas and populated areas. Some solutions to wastedisposal have the potential to significantly reduce the environmental risks and liabilities, but represent higher costs in the stages of deployment and operation. The addition of mining waste as raw material in the development of commercial products reduces the environmental impacts, transforming the waste into a positive element in the generation of employment and income. This thesis studies the incorporation of waste iron ore in two clays, one from the ceramic industry of the City of Natal and the other from the ceramic industry of the Seridó Region, both in the State of Rio Grande do Norte, Brazil. Percentages of iron ore waste of 5%, 10% , 15%, 20%, 25% and 30% were used in the tested ceramic matrix. The two clays and the iron ore waste used as part of this investigation were characterized by X-ray diffraction tests, X-ray fluorescence tests, differential thermal analysis, thermogravimetric analysis and dilatometric analysis. The samples were sintered under temperatures of 850 °C, 950 °C and 1050°C at a heating rate of 5 °C/min with isotherms of two hours. The following tests were performed with the samples: linear shrinkage, water absorption, apparent porosity, apparent density, mass loss in fire and bending resistance in order to obtain their physical and mechanical properties. An amount of 5% of waste iron ore in the matrix clay at a temperature of 850 0C resulted in na increase of about 65% in the tensile strength of the clay samples from the Natal ceramic industry. A linear shrinkage of only 0.12% was observed for the samples, which indicates that the physical properties of the final product were not influenced by the addition of the waste

Estudo de massa cerâmica triaxial visando à otimização do ciclo de queima da indústria de cerâmica estrutural

Over recent years the structural ceramics industry in Brazil has found a very favorable market for growth. However, difficulties related to productivity and product quality are partially inhibiting this possible growth. An alternative for trying to solve these problems and, thus, provide the pottery industry the feasibility of full development, is the substitution of firewood used in the burning process by natural gas. In order to contribute to this process of technological innovation, this paper studies the effect of co-use of ceramic phyllite and kaolin waste on the properties of a clay matrix, verifying the possible benefits that these raw materials can give to the final product, as well as the possibility of such materials to reduce the heat load necessary to obtain products with equal or superior quality. The study was divided into two steps: characterization of materials and study of formulations. Two clays, a phyllite and a residue of kaolin were characterized by the following techniques: laser granulometry, plasticity index by Atterberg limits, X-ray fluorescence, X-ray diffraction, mineralogical composition by Rietveld, thermogravimetric and differential thermal analysis. To study the formulations, specifically for evaluation of technological properties of the parts, was performed an experimental model that combined planning involving a mixture of three components (standard mass x phyllite x kaolin waste) and a 23 factorial design with central point associated with thermal processing parameters. The experiment was performed with restricted strip-plot randomization. In total, 13 compositional points were investigated within the following constraints: phyllite ≤ 20% by weight, kaolin waste ≤ 40% by weight, and standard mass ≥ 60% by weight. The thermal parameters were used at the following levels: 750 and 950 °C to the firing temperature, 5 and 15 °C/min at the heating rate, 15 and 45min to the baseline. The results showed that the introduction of phyllite and/or kaolin waste in ceramic body produced a number of benefits in properties of the final product, such as: decreased absorption of water, apparent porosity and linear retraction at burn; besides the increase in apparent specific mass and mechanical properties of parts. The best results were obtained in the compositional points where the sum of the levels of kaolin waste and phyllite was maximal (40% by weight), as well as conditions which were used in firing temperatures of 950 °C. Regarding the prospect of savings in heat energy required to form the desired microstructure, the phyllite and the residue of kaolin, for having small particle sizes and constitutions mineralogical phases with the presence of fluxes, contributed to the optimization of the firing cycle.

Predictive models of buildings energy consumption

Dissertação de Mestrado, Engenharia Electrónica e Telecomunicações, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Structural characterization and comparative analysis of human and piscine cartilage acidic protein (CRTAC1/CRTAC2)

Dissertação de mestrado, Biotecnologia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014

Do pouco mais que nada até ao coletivo orgânico (sobre o processo de criação do espetáculo Tem dói-dói?)

Dissertação de Mestrado, Comunicação, Cultura e Artes, Especialização em Teatro e Intervenção Social e Cultural, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2014

Avaliação da alfarrobeira como sumidouro de carbono e o mercado de carbono: estudo referente à região do Algarve

Dissertação de mestrado, Avaliação e Gestão Ambiental, Universidade do Algarve, 2011

Cosmologia e astrofísica no ensino secundário

Dissertação de mest. em Física - área de especialização em Física para Ensino, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2003

Diseño de herramientas mercadológicas para potenciar la demanda de servicios turísticos en el parque acuático paraiso de la montañona, ubicado en el municipio de Concepción Quezaltepeque, departamento de Chalatenango.

El parque acuático Paraíso de la Montañona es un centro turístico ubicado en el Cantón Llano Grande del municipio de Concepción Quezaltepeque, Chalatenango; se dedica al turismo ecológico ofreciendo al turista una diversidad de servicios que garantizan su diversión y esparcimiento, su infraestructura está conformada por tres piscinas, zonas verdes y cabañas. Su principal atractivo es la comodidad, amplitud y seguridad de las instalaciones; posee ciertas fortalezas entre las cuales se pueden mencionar la muy buena atención del cliente, la higiene de las piscinas y el clima agradable. No obstante, el turicentro presenta innegables debilidades en cuanto al funcionamiento y acceso, debido a que la calle se encuentra deteriorada en muchos tramos, además, hasta el momento no se hace nada por promocionar y darle publicidad a los aspectos más sobresalientes del parque, añadido a eso, su administración demuestra características deficientes a la hora de tomar decisiones. Todos estos aspectos dieron origen a la investigación que tiene como propósito fortalecer todas las cualidades sobresalientes del centro turístico y diseñar estrategias que permitan solucionar los problemas que ocasionan la pérdida de clientes. Durante el desarrollo de la investigación fue necesario apoyarse en los métodos analítico y sintético, específicamente en la etapa de interpretación de los resultados, además se utilizaron guías de entrevista, cuestionarios dirigidos a los clientes y a los empleados del parque acuático, así como también guías de observación durante la etapa de recolección de la información. El universo de estudio que se consideró para llevar a cabo la investigación está compuesto por los habitantes de los municipios de Concepción Quezaltepeque, Comalapa y Ciudad de Chalatenango, de los cuales se tomó como muestra la población comprendida en el rango de 20 a 39 años de edad, que en su totalidad la conforman 10,969 personas. La información recopilada nos muestra que las visitas de los turistas han disminuido enormemente debido al descuido de la administración en cuanto a la implementación de promociones que incentiven a los clientes y a la poca publicidad que se tiene para dar a conocer los principales atractivos del parque. También se tiene que los mejores servicios que se ofrecen son la comodidad de las instalaciones, la excelencia en la atención al cliente y la amplitud e higiene de las piscinas, esto es muy importante ya que se convierten en las principales fortalezas del centro turístico. Además, las autoridades encargadas del parque no emplean planes estratégicos que guíen su accionar a mediano y largo plazo, dificultando la obtención de ventajas competitivas que le permitan la sostenibilidad en el tiempo. El plan estratégico de mercadotecnia propuesto para el parque acuático está compuesto por un conjunto de estrategias ofensivas que se encargan de maximizar las fortalezas y aumentar las oportunidades, estrategias defensivas que son utilizadas para minimizar las amenazas, estrategias adaptativas y de supervivencia ambas empleadas para mejorar las deficiencias internas y la sostenibilidad del negocio en el tiempo respectivamente.

A sustentabilidade ambiental das cidades sob a ótica da pegada de carbono e do sistema verde de Brasília

Tese (doutorado)—Universidade de Brasília, Centro de Desenvolvimento Sustentável, 2015.

Efeito da tecnologia de microondas nas propriedades tecnológicas dos componentes de cerâmica estrutural

O processamento térmico de materiais cerâmicos via energia de microondas, no estágio atual, vem ganhando cada dia mais importância, tendo em vista suas inúmeras aplicações, como por exemplo: aplicação de microondas na área de processamento mineral (aquecimento de minérios antes da moagem, secagem, redução carbotérmica de óxidos minerais, lixiviação, fusão, pré-tratamento de minérios e concentrados de ouro refratário, regeneração de carvão, etc. de acordo com Kigman & Rowson, 1998). Em virtude de uma série de vantagens em potencial, frente aos métodos convencionais de aquecimento, como redução no tempo de processamento; economia de energia; diminuição do diâmetro médio das partículas e melhoramento nas propriedades tecnológicas em geral, esta tecnologia vem se destacando. Neste contexto, o objetivo geral deste trabalho, é desenvolver uma pesquisa visando identificar e caracterizar novas opções de matérias-primas cerâmicas como argilas, feldspatos e caulins que sejam eficazes para definir a formulação de uma ou mais massas para produção de componentes de cerâmica estrutural com propriedades físicas, mecânicas e estéticas adequadas após passarem por sinterização convencional e por energia de microondas destacando as vantagens desta última. Além dos requisitos técnicos e de processo, as formulações apresentadas deverão atender às expectativas de preço e de logística de fornecimento. No estudo foram conformados corpos-de-prova por extrusão e prensagem, sinterizados em fornos microondas e convencional, sob ciclos de queima mais rápidos que os atualmente praticados. As matérias-primas foram caracterizadas e analisadas, utilizando as técnicas de fluorescência por raios X (FRX), difração por raios X (DRX), análise térmica diferencial (DTA), análise térmica gravimétrica (DTG), análise granulométrica (AG), microscopia eletrônica de varredura (MEV), absorção d agua (AA), massa especifica aparente (MEA), porosidade aparente (PA), retração linear (RL) e tensão de ruptura e flexão (TRF). Os resultados obtidos indicaram que as propriedades tecnológicas de Absorção de água (AA) e Tensão de Ruptura e flexão (TRF), proposto no trabalho foram adquiridos com sucesso e estão bem além do limite exigido pelas especificações das normas da ABNT NBR 15.270/05 e 15.310/09

Estudo da adição de resíduo de scheelita em matriz cerâmica: formulação, propriedades físicas e microestrutura

Extractivism mineral is considered an activity highly degrading, due to the large volume of material that he moves in the form of ore and residues. The vast majority of mining companies do not show any technology or economically viable application that will allow the recycling of mineral residue, these being launched in areas receiving located the "open skies" degrade the environment. In Rio Grande do Norte to the production of ceramic red restricts their activities to the production of products such as: solid bricks, ceramic blocks, tiles, among others. Seeking to unite experiences and technical information that favor sustainable development, with important benefits to the construction sector and civil society in general, the present work studies the incorporation of the residue of scheelite in ceramic matrix kaolinitic, coming from the municipality of Boa Saúde - RN, in percentage of 5 %, 10 %, 20 %, 30% 40% and 50 %, by evaluating its microstructure, physical properties and formulation. The raw materials were characterized through the trials of X ray fluorescence, Diffraction of X rays, Differential Thermal Analysis and Termogravimetric Analysis. The samples were formed and fired at temperatures of 850o, 900o, 1000o, 1050o, 1100o, 1150o and 1200 oC, with isotherm of 1 hour and heating rate of 10 oC/min. Assays were performed technological of loss to fire, Water Absorption, Apparent Porosity, Apparent Density, Mass Loss in Fire and Bending Resistance; in addition to the Scanning Electron Microscopy, analyzing their physical and mechanical properties. The use of residue of scheelite in ceramic mass kaolinitic provided a final product with technological properties that meet the technical standards for the production of bricks and roofing tiles, with the percentage of 20% of waste that showed the best results

Síntese e caracterização de ferrita ni-zn pelo método dos precursores poliméricos calcinada por energia de microondas

Magnetic ceramics have been widely investigated, especially with respect to intrinsic and extrinsic characteristics of these materials. Among the magnetic ceramic materials of technological interest, there are the ferrites. On the other hand, the thermal treatment of ceramic materials by microwave energy has offered various advantages such as: optimization of production processes, high heat control, low consumption of time and energy among others. In this work were synthesized powders of Ni-Zn ferrite with compositions Ni1- xZnxFe2O4 (0.25 ≤ x ≤ 0.75 mols) by the polymeric precursor route in two heat treatment conditions, conventional oven and microwave energy at 500, 650, 800 and 950°C and its structural, and morphological imaging. The materials were characterized by thermal analysis (TG/ DSC), X-ray diffraction (XRD), absorption spectroscopy in the infrared (FTIR), scanning electron microscopy (SEM), X-ray spectroscopy and energy dispersive (EDS) and vibrating sample magnetometry (VSM). The results of X-ray diffraction confirmed the formation of ferrite with spinel-type cubic structure. The extrinsic characteristics of the powders obtained by microwave calcination and influence significantly the magnetic behavior of ferrites, showing particles ferrimagnéticas characterized as soft magnetic materials (soft), is of great technological interest. The results obtained led the potential application of microwave energy for calcining powders of Ni-Zn ferrite

Desenvolvimento de bioblendas poliméricas a partir de gelatina bovina e de tilápia com amido de milho

The natural raw materials acquired special importance beside the mineral raw materials with the need for using alternative sources to oil, because they can be used to produce biopolymers. Gelatin, produced from the denaturation of collagen, and starch, an abundant polysaccharide in various plants, are examples of biopolymers which have several technological applications, especially in films. The objective of this work is to produce polymeric bioblends with gelatin and corn starch using two types of gelatin: commercial bovine gelatin and gelatin produced from mechanically separated flesh of tilapia (Oreochromis niloticus). For the extraction of tilapia gelatin 3 distinct pretreatments, followed by extraction in distilled water under heating were performed. The properties of gelatin extracted were similar to bovine gelatin, and the differences can be explained by the difference in extraction processes and sources. Blends of commercial gelatin and starch were produced in an internal mixer from a Haake torque rheometer, to study the behavior of the gelatin mixture with starch, thus, the same compositions were processed by twin screw extrusion, to define the mixing parameters. Subsequently, the extrusion of blends of tilapia gelatin and corn starch was carried out in the same twin screw extruder. The physico-chemical, rheological and morphological properties of the blends with thermoplastic starch and gelatin were studied. It was found that various properties vary linearly with increasing concentration of the components. The blends produced are immiscible, and among the two gelatins, tilapia gelatin showed a better interfacial adhesion with the corn starch. Regarding the morphology, gelatins formed the dispersed phase in all compositions studied, even in compositions rich in starch. Can be concluded that the procedure for tilapia gelatin extraction is feasible and advantageous, and the increasing in its scale to a reactor of 30 liters is possible, with a satisfactory yield. The bioblends of bovine gelatin/corn starch and tilapia gelatin/corn starch were successfully produced, and the processing conditions were appropriate

Propuesta de estratégias de mercadotecnia a corto plazo para el aumento de la demanda de los servicios en el Polideportivo municipal Vitoria Gasteiz del municipio de Nejapa, departamento de San Salvador.

El Municipio de Nejapa siempre careció de centros de recreación adecuados, y espacios donde practicar deportes, a pesar que su población en su mayoría son jóvenes, está es sin duda una de las razones de peso para la creación de un polideportivo, que permitiera alternativas de recreación y esparcimiento en el Municipio. En su inicio este proyecto nació para cumplir una función social en el municipio, la cual era la de entretener a niños, jóvenes y adultos en actividades deportivas y de esparcimiento; por lo que se construyeron canchas para las diferentes prácticas deportivas. Posterior a esto surgió la iniciativa de la construcción de un área de piscinas para satisfacer las necesidades de recreación de la población y visitantes del Polideportivo Municipal Vitoria Gasteiz, que a la vez generara los recursos necesarios para su mantenimiento. Actualmente el Polideportivo Municipal muestra la necesidad de cumplir dos funciones: función social y económica, siendo ésta ultima la básica para el sostenimiento y desarrollo del Polideportivo y además para llevar a cabo proyectos sociales dentro del Municipio. En ese ámbito, la investigación se orienta a contribuir con el Gobierno Municipal de Nejapa, a través de una propuesta de Estrategias de Mercadotecnia, que permita al Polideportivo el aumento de la demanda de sus servicios; ya que las estrategias de mercadotecnia son líneas generales de acción, a través de las cuales una institución logra sus objetivos. Para el caso del Polideportivo Municipal Vitoria Gasteiz, la propuesta de estrategias requerida está orientada a implementarse en un corto plazo. En base a lo anterior, los objetivos de la investigación son: Diseñar estrategias de Mercadotecnia a corto plazo que permitan al Polideportivo Municipal mejorar y dar a conocer sus servicios, logrando de esta manera aumentar su demanda de visitantes. Obtener un diagnóstico de la situación actual del Polideportivo, a partir de los resultados obtenidos en la investigación de campo, para definir las líneas de acción que permitan el aumento de la demanda de visitantes al Polideportivo. Proponer a través de la mezcla de mercadotecnia estrategias a corto plazo que permitan mejorar y dar a conocer los servicios. La metodología de investigación se llevó a cabo con la ayuda de fuentes primarias, las cuales fueron la observación directa y los cuestionarios dirigidos a empleados y visitantes del Polideportivo; y las fuentes secundarias como: libros, información escrita brindada por el administrador del Polideportivo y folletos obtenidos de Internet. Con esto se determinó que el Polideportivo Municipal no tiene definido los cursos generales de acción que le permitan el desarrollo de sus actividades. Por lo tanto, la prestación de los servicios no se brinda eficientemente. Además la utilización de la promoción y publicidad es limitada. Todo lo antes mencionado puede mejorarse de manera inmediata con el diseño de estrategias a corto plazo a partir de una mezcla de mercadotecnia que incorporen las mejoras en cada elemento analizado en la mezcla.