Análisis cinético y estudio de la emisión de contaminantes durante la descomposición térmica de circuitos impresos considerando el efecto de la presencia de metales

Generalitat Valenciana: PROMETEO/2009/043/FEDER. Ministerio de Educación y Ciencia: CTQ2008-05520.

Estudio de la descomposición térmica de tarjetas de circuito impreso de teléfonos móviles

Comunicación presentada en el II Congreso de Estudiantes de Ingeniería Química de la UA, Universidad de Alicante, 10-11 octubre 2012.

Análisis de los contaminantes generados en la descomposición térmica de un retardante de llama bromado: tetrabromobisfenol A

Comunicación presentada en la III Reunión Nacional sobre Dioxinas, Furanos y Compuestos Orgánicos Persistentes Relacionados, Santander, 30 junio-1 julio 2011.

Estudio de la descomposición térmica de tetrabromobisfenol A

Resumen de la comunicación presentada en el XIII Congreso Nacional de Ingeniería Química, Madrid, 18-20 noviembre 2010.

Avaliação térmica provocada pela furação no tecido ósseo

Este trabalho tem como objetivo avaliar o efeito da temperatura no osso devido ao aquecimento provocado pelo processo de furação. Foram realizadas visitas a duas clínicas para acompanhamento da técnica de implantologia dentária e recolhidas imagens termográficas para a leitura da temperatura gerada na broca após o processo de furação. Na colocação de implantes dentários por exemplo, as variáveis que interferem no processo de furação do osso são: a velocidade, o material, o diâmetro, o comprimento e a geometria da ponta da broca. Com este trabalho pretende-se verificar, experimental e numericamente, as variáveis que interferem no aquecimento da estrutura óssea. Para isso, são utilizados materiais compósitos com características similares ao osso cortical e trabecular. A metodologia apresentada revela-se útil e diferenciadora de outros trabalhos, pois são utilizados materiais com características similares aos materiais in vivo. Os métodos experimentais utilizados em laboratório são baseados nas técnicas de termografia e termopares durante a furação dos diferentes materiais. Paralelamente, são utilizados modelos teóricos numéricos, com o recurso à técnica de elementos finitos, para a discussão de resultados. Após a elaboração do trabalho conclui-se que a temperatura na broca é superior à temperatura no osso e aumenta consoante a estrutura do material, isto é, se o material possuir cavidades na sua estrutura a temperatura na broca não é tão elevada como no material compacto.

Estudo do comportamento térmico de edifícios : análise da influência da orientação e inércia térmica

A recente transposição da directiva europeia relativa ao Desempenho Energético dos Edifícios (2002/91/CE) e posteriormente a (2010/31/EU) pelo Decreto-Lei n.º 118/2013 de 20 de Agosto, incluiu num único diploma o Sistema de Certificação Energética dos Edifícios (SCE), o Regulamento do Desempenho Energético dos Edifícios de Habitação (REH) e o Regulamento de Desempenho Energético dos Edifícios de Comércio e Serviços (RECS), introduzindo desta forma novos parâmetros de conforto interior para os edifícios a construir em Portugal. A necessidade e a curiosidade em aprofundar o estudo do desempenho energético de edifícios, em particular em dois parâmetros que influenciam o cálculo, a inércia térmica e a orientação solar, esteve na base da escolha deste trabalho. Neste sentido foram estudadas várias soluções construtivas correntes da nossa construção para se conseguir compreender a variação da inércia térmica das duas moradias em estudo e assim determinar a influência que tem a inércia térmica no conforto interior. Foi também tido em conta neste estudo, a variação da orientação solar e a sua influência nos ganhos térmicos para a estação de aquecimento e arrefecimento. Deste modo conseguiu-se aferir a influência que a energia solar tem nos cálculos do conforto interior para as várias orientações solares. Por curiosidade calcularam-se também os dados das moradias sem obstruções solares de modo a fazer uma comparação com e sem os elementos que provocam sombreamento nos vãos solares. Por último utilizou-se o software Design Builder para fazer a simulação dinâmica das moradias e comparar com os resultados obtidos do cálculo regulamentar do REH.

Síntese e caracterização estrutural, magnética e térmica da hidroxiapatita dopada com ferro

In this work, composites were prepared using high energy mechanical milling from the precursors hydroxyapatite - HAp (Ca10(PO4)6(OH)2) and metallic iron ( -Fe ). The main goal here is to study composites in order to employ them in magnetic hyperthermia for cancer therapy. The produced samples were characterized by X-ray di raction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), magnetization curves as a function of applied eld (MxH), and nally measurements of magnetic hyperthermia. The XRD patterns of the milled samples HAp/Fe revealed only the presence of precursor materials. The SEM showed clusters with irregular shapes. The magnetization curves indicated typical cases of weak ferromagnetic behavior. For samples submitted to grinding and annealing, the identi ed phases were: HAp (Ca10(PO4)6(OH)2), hematite (Fe2O3) and Calcium Iron Phosphate (Ca9Fe(PO4)7). Analyzing the results of MxH, there was a reduction of the saturation magnetization, given that the Fe was incorporated into HAp. Hysteresis curves obtained at 300 K are characteristics of samples possessing over a phase. At 77 K, the behavior of the hysteresis curve is in uenced by the presence of hematite, which is antiferromagnetic. Already at T = 4.2 K, it is observed a weak ferromagnetic behavior. Furthermore, there is the e ect of exchange bias. Regarding the magnetic hyperthermia, the results of temperature measurements as a function of the alternating eld are promising for applications in magnetic hyperthermia and other biomedical applications.

Estimativa do fluxo de calor e da difusividade térmica do solo, baseado na solução da derivada temporal fracionária de meia ordem em ferramenta de software

The soil heat flux and soil thermal diffusivity are important components of the surface energy balance, especially in ar id and semi-arid regions. The obj ective of this work was to carry out to estimate the soil heat flux from th e soil temperature measured at a single depth, based on the half-order time derivative met hod proposed by Wang and Bras (1999), and to establish a method capable of es timating the thermal diffusivity of the soil, based on the half order derivative, from the temporal series of soil temperature at two depths. The results obtained in the estimates of soil heat flux were compared with the values of soil heat flux measured through flux plates, and the thermal di ffusivity estimated was compared with the measurements carried out in situ. The results obtained showed excellent concordance between the estimated and measured soil heat flux, with correlation (r), coeffici ent of determination (R 2 ) and standard error (W/m 2 ) of: r = 0.99093, R 2 = 0.98194 and error = 2.56 (W/m 2 ) for estimated period of 10 days; r = 0,99069, R 2 = 0,98147 and error = 2.59 (W/m 2 ) for estimated period of 30 days; and r = 0,98974, R 2 = 0,97958 and error = 2.77 (W/m 2 ) for estimated period of 120 days. The values of thermal di ffusivity estimated by the proposed method showed to be coherent and consis tent with in situ measured va lues, and with the values found in the literature usi ng conventional methods.

Avaliação térmica e desempenho do processo de secagem de misturas de graviola e leite em secador de leito de jorro

The soursop (A. muricata) is a fruit rich in minerals especially the potassium content. The commercialization of soursop in natura and processed has increased greatly in recent years. Drying fruit pulp in order to obtain the powdered pulp has been studied, seeking alternatives to ensure the quality of dehydrated products at a low cost of production. The high concentration of sugars reducing present in fruits causes problems of agglomeration and retention during fruit pulp drying in spouted bed dryers. On the other hand in relation to drying of milk and fruit pulp with added milk in spouted bed, promising results are reported in the literature. Based on these results was studied in this work drying of the pulp soursop with added milk in spouted bed with inert particles. The tests were based on a 24 factorial design were evaluated for the effects of milk concentration (30 to 50% m/m), drying air temperature (70 to 90 °C), intermittency time (10 to 14 min), and ratio of air velocity in relation to the minimum spout (1.2 to 1.5) on the rate of production, of powder moisture, yield, rate of drying and thermal efficiency of the process. There were physical and chemical analysis of mixtures, of powders and of mixtures reconstituted by rehydration powders. Were adjusted statistical models of first order to data the rate of production, yield and thermal efficiency, that were statistically significant and predictive. An efficiency greater than 40% under the conditions of 50% milk mixture, at 70 ° C the drying air temperature and 1.5 for the ratio between the air velocity and the minimum spout has been reached. The intermittency time showed no significant effect on the analyzed variables. The final product had moisture in the range of 4.18% to 9.99% and water activity between 0.274 to 0.375. The mixtures reconstituted by rehydration powders maintained the same characteristics of natural blends.

Caracterização mecânica, térmica e acústica de um compósito que utiliza rejeitos de mármore, granito e EPS para a fabricação de blocos para a construção civil

The use of composite materials for the construction industry has been the subject of numerous scientific papers in Brazil and in the world. One of the factors that motivate this quest is the housing deficit that countries especially the third world face. In Brazil this deficit reaches more than 6.5 million homes, around 12% of all US households . This paper presents a composite that was obtained from waste generated in processes for the production of granite and marble slabs, cement, gypsum, sand, crushed EPS and water. These wastes cause great damage to the environment and are thrown into landfi lls in bulk. The novelty of the work is in the combined study thermal, mechanical and acoustic composite obtained in real situation of rooms that are part of an experimental housing. Many blocks were made from cement compositions, plaster, foam, sand, marb le and / or granite, preliminary tests of mechanical and thermal resistance were made by choosing the most appropriate proportion. Will be given the manufacturing processes and assembly units 500 units 10 x 80 x 28 cm produced for the construction of an ex perimental home. We studied what kind of block and residue, marble or granite, made it more feasible for the intended purpose. The mechanical strength of the produced blocks were above 3.0 MPa. The thermal resistance of the blocks was confirmed by the maxi mum temperature difference between the inner and outer walls of rooms built around 8.0 ° C. The sound absorption for optimal room was around 31%. Demonstrated the feasibility of using the blocks manufactured with composite material proposed for construction.

Modelos de condutividade térmica em rochas silicáticas, com ênfase em rochas da província Borborema, NE do Brasil

A practical approach to estimate rock thermal conductivities is to use rock models based just on the observed or expected rock mineral content. In this study, we evaluate the performances of the Krischer and Esdorn (KE), Hashin and Shtrikman (HS), classic Maxwell (CM), Maxwell-Wiener (MW), and geometric mean (GM) models in reproducing the measures of thermal conductivity of crystalline rocks.We used 1,105 samples of igneous and metamorphic rocks collected in outcroppings of the Borborema Province, Northeastern Brazil. Both thermal conductivity and petrographic modal analysis (percent volumes of quartz, K-feldspar, plagioclase, and sum of mafic minerals) were done. We divided the rocks into two groups: (a) igneous and ortho-derived (or meta-igneous) rocks and (b) metasedimentary rocks. The group of igneous and ortho-derived rocks (939 samples) covers most the lithologies de_ned in the Streckeisen diagram, with higher concentrations in the fields of granite, granodiorite, and tonalite. In the group of metasedimentary rocks (166 samples), it were sampled representative lithologies, usually of low to medium metamorphic grade. We treat the problem of reproducing the measured values of rock conductivity as an inverse problem where, besides the conductivity measurements, the volume fractions of the constituent minerals are known and the effective conductivities of the constituent minerals and model parameters are unknown. The key idea was to identify the model (and its associated estimates of effective mineral conductivities and parameters) that better reproduces the measures of rock conductivity. We evaluate the model performances by the quantity  that is equal to the percentage of number of rock samples which estimated conductivities honor the measured conductivities within the tolerance of 15%. In general, for all models, the performances were quite inferior for the metasedimentary rocks (34% <  < 65%) as compared with the igneous and ortho-derived rocks (51% <  < 70%). For igneous and ortho-derived rocks, all model performances were very similar ( = 70%), except the GM-model that presented a poor performance (51% <  < 65%); the KE and HS-models ( = 70%) were slightly superior than the CM and MW-models ( = 67%). The quartz content is the dominant factor in explaining the rock conductivity for igneous and ortho-derived rocks; in particular, using the MW-model the solution is in practice vi UFRN/CCET– Dissertação de mestrado the series association of the quartz content. On the other hand, for metasedimentary rocks, model performances were different and the performance of the KEmodel ( = 65%) was quite superior than the HS ( = 53%), CM (34% <  < 42%), MW ( = 40%), and GM (35% <  < 42%). The estimated effective mineral conductivities are stable for perturbations both in the rock conductivity measures and in the quartz volume fraction. The fact that the metasedimentary rocks are richer in platy-minerals explains partially the poor model performances, because both the high thermal anisotropy of biotite (one of the most common platy-mineral) and the difficulty in obtaining polished surfaces for measurement coupling when platyminerals are present. Independently of the rock type, both very low and very high values of rock conductivities are hardly explained by rock models based just on rock mineral content.

Estudo de um permutador de calor para aplicação em sistemas de recuperação de energia térmica

Grande parte da energia contida no combustível consumido por um motor de combustão interna é desperdiçada sob forma de calor, através do sistema de refrigeração do motor, do sistema de recirculação dos gases de escape e principalmente através dos gases de escape. Daí o interesse no estudo de sistemas que permitem o aproveitamento dessa energia residual dos veículos automóveis. Este trabalho centra-se no estudo de sistemas de aproveitamento da energia térmica contida nos gases de escape dos veículos automóveis, sendo o objetivo principal o estudo do permutador de calor que será utilizado para recuperação da energia térmica. Existem vários tipos de permutadores, na sua escolha entram fatores como as características dos fluidos de trabalho envolvidos, o custo, facilidade de manutenção, a aplicação. Para o caso deste estudo selecionou-se um permutador de carcaça e tubos e um permutador de tubos concêntricos. Uma vez que a seleção e otimização de um permutador de calor implica a minimização da perda de carga dos gases de escape e a maximização da eficiência térmica do sistema, numa primeira fase selecionou-se a geometria mais adequada. Em seguida fez-se uma comparação de diferentes modelos de cálculo da perda de carga e analisou-se o desempenho termo hidráulico do permutador. Por fim realizou-se um estudo paramétrico para verificar a influência dos parâmetros de construção (número de tubos, diâmetro e comprimento dos tubos).

Modos projetuais de simulação: uso de ferramentas de simulação térmica no processo projetual de arquitetura

This thesis aims to describe and demonstrate the developed concept to facilitate the use of thermal simulation tools during the building design process. Despite the impact of architectural elements on the performance of buildings, some influential decisions are frequently based solely on qualitative information. Even though such design support is adequate for most decisions, the designer will eventually have doubts concerning the performance of some design decisions. These situations will require some kind of additional knowledge to be properly approached. The concept of designerly ways of simulating focuses on the formulation and solution of design dilemmas, which are doubts about the design that cannot be fully understood nor solved without using quantitative information. The concept intends to combine the power of analysis from computer simulation tools with the capacity of synthesis from architects. Three types of simulation tools are considered: solar analysis, thermal/energy simulation and CFD. Design dilemmas are formulated and framed according to the architect s reflection process about performance aspects. Throughout the thesis, the problem is investigated in three fields: professional, technical and theoretical fields. This approach on distinct parts of the problem aimed to i) characterize different professional categories with regards to their design practice and use of tools, ii) investigate preceding researchers on the use of simulation tools and iii) draw analogies between the proposed concept, and some concepts developed or described in previous works about design theory. The proposed concept was tested in eight design dilemmas extracted from three case studies in the Netherlands. The three investigated processes are houses designed by Dutch architectural firms. Relevant information and criteria from each case study were obtained through interviews and conversations with the involved architects. The practical application, despite its success in the research context, allowed the identification of some applicability limitations of the concept, concerning the architects need to have technical knowledge and the actual evolution stage of simulation tools

Recuperação de componentes de metal duro por projeção térmica

The main objective of this work is the development of a hardmetal components (WC-6%Co) recovery method by thermal deposition process. The thermal deposition technique used was HVOF (high velocity oxygen-fuel). The HVOF enables depositions of thick coatings (100-500 µm) with low porosity levels, high hardness and excellent adhesion. Before deposition, hardmetal samples with different geometries (plates and cylinders) were finished in order to have different roughness. The influence of these parameters in adhesion was studied. After this step, different re-sintering temperatures were used, in order to determine which one allows to obtain the maxima densification, elements distribution and metallurgical bonding. The re-sintering promotes the densification of the coating, with an increase of its hardness and metallurgical bonding formation. The inclusion of an intermetallic layer was tested along with different layer parameters. In liquid phase sintering (1383 and 1455 ºC) a complete densification of the coating occurred, while a bonding between the substrate and the coating only partially happened. The results of SEM/EDS show low levels of porosity and a complete and uniform distribution of the elements of the alloy. The cylindrical samples without intermetallic layer showed the lowest level of porosity and best metallurgical bonding. When the substrate surface was polished (Ra = 0.05 mm) lower levels of porosity and greater metallurgical bonding were found for both geometries. Taking into account the results obtained in this study, we can conclude that the implementation of this process is appropriate for cylindrical components with a polished surface. In these components the intermetallic layer is unnecessary and punctual defects like pores can be repaired with this process.

Modelización térmica del proceso de diamantado

Realización de un modelo numérico mediante elementos finitos del proceso de diamantado, mediante el cual ser capaces de determinar el flujo de calor entrante en el diamante.