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.

Radiofrecuencia pulsada sobre el nervio dorsal del pene: tratamiento eficaz para la neuralgia refractaria del pudendo

La neuralgia del pudendo se define como un síndrome doloroso neuropático, que involucra al dermatomo y a la inervación motora del nervio pudendo. Cualquier punto de su trayecto, desde su origen hasta sus ramificaciones terminales, es susceptible de sufrir diferentes grados de afectación o lesión. La localización del dolor puede ser perineal, rectal o en el área del clítoris/pene, presentándose de forma unilateral o bilateral; se agrava al sentarse y disminuye o desaparece al estar de pie; habitualmente respeta el descanso nocturno y puede asociarse a disfunción urinaria, anal e incluso sexual. Son múltiples las causas que pueden provocar la afectación del nervio pudendo, como partos, caídas, golpes directos y cirugías pélvicas. Esta patología constituye una entidad relativamente frecuente en las unidades de dolor crónico. Son varias las terapias utilizadas, incluyendo fármacos, bloqueos nerviosos del pudendo, cirugía descompresiva y neuromodulación de cordones posteriores medulares. Presentamos el caso de un paciente que, tras ser sometido a prostatectomía radical, consultó por dolor crónico continuo de tipo quemante junto a crisis lancinantes en parte distal derecha del pene (territorio del pudendo) y en el que aplicamos radiofrecuencia pulsada sobre el nervio dorsal derecho del pene obteniendo un buen resultado. Son varios los autores que han publicado tratamientos exitosos con radiofrecuencia pulsada del pudendo para el tratamiento de la neuralgia de dicho nervio, pero hasta ahora no se ha publicado ningún artículo de radiofrecuencia pulsada sobre los nervios dorsales del pene.

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.

Modelo teórico para cuantificar la eficiencia térmica del calentador eléctrico en una secadora doméstica de ropa

En este trabajo de difusión se presenta la mejora de la generación y transferencia de calor en el calentador eléctrico de una secadora doméstica de ropa, con el desarrollo de un modelo teórico para estimar la eficiencia térmica, basado en el flujo másico y la potencia eléctrica del calentador como variables de entrada, y la eficiencia térmica del calentador como variable de salida, con el calentador analizado como un componente aislado. Se realizaron pruebas al calentador para determinar la función matemática de su eficiencia térmica. Del análisis de resultados se observó la tendencia exponencial típica de un sistema sobreamortiguado, base del modelo matemático cuyo coeficiente de predicción es 0.96.El modelo matemático se comprobó con flujo másico alto obteniendo un error relativo máximo de 0.66 %, y provee de información suficiente para elevar la eficiencia en 7.7%. El rango de potencia en el que fue probado el modelo matemático desarrollado para el calentador es de 1 KW hasta 5 KW, el cual es el rango recomendado para su uso.

Síntese, caracterização e cinética da decomposição térmica dos materiais cerâmicos PrMO3 (M = Ni ou Co)

In this work have been studied the preparation, characterization and kinetic study of decomposition of the polymerizing agent used in the synthesis under non-isothermal condition ceramics PrMO3 of general formula (M = Co and Ni). These materials were obtained starting from the respective metal nitrates, as a cations source, and making use of gelatin as polymerizing agent. The powders were calcined at temperatures of 500°C, 700°C and 900°C and characterized by X-ray Diffraction (XRD), Thermogravimetric Analysis (TG / DTG/ DTA), Infrared Spectroscopy (FTIR), Temperature Programmed Reduction (TPR) and Scanning Electron Microscopy (SEM). The perovskite phase was detected in all the X-rays patterns. In the infrared spectroscopy observed the oxide formation as the calcination temperature increases with the appearance of the band metal - oxygen. The images of SEM revealed uniform distribution for the PrCoO3 and particles agglomerated as consequence of particle size for PrNiO3. From the data of thermal analysis, the kinetics of decomposition of organic matter was employed using the kinetics methods called Model Free Kinetics and Flynn and Wall, in the heating ratios 10, 20 and 30° C.min-1 between room temperature and 700°C. Finally, been obtained the values of activation energy for the region of greatest decomposition of organic matter in samples that were determined by the degree of conversion (α)

Estudio de márgenes tras tumorectomía seguida de radiofrecuencia en cirugía conservadora del cáncer de mama

Introducción: La cirugía conservadora constituye hoy el tratamiento estándar en el ca. mama. La recurrencia local debe evitarse en la medida de lo posible, en tanto en cuanto condiciona un mayor estrés para la paciente, la obligatoriedad de tratamientos más agresivos, y una disminución de la supervivencia. Para ello, la obtención de márgenes libres es un factor clave. Pese a todos los esfuerzos por obtener dichos márgenes libres en un único acto quirúrgico, sigue existiendo una alta tasa de reintervenciones para su obtención. La ARF es un procedimiento aún en investigación sobre la que existen pocos datos relativos a los detalles de la técnica y su reproductibilidad, así como su eficacia en la obtención de márgenes libres y menos aún sobre persistencia de enfermedad, recurrencia local y repercusión sobre la supervivencia, para lo que se necesitaran estudios con amplios grupos de pacientes y tiempo de seguimiento. Nosotros nos proponemos aportar datos relativos a la ARF, centrados en un protocolo de la técnica de aplicación de la ARF, valoración de la utilidad de la ARF en la obtención de margen libres y repercusión de la ARF sobre las complicaciones y el resultado estético. Material y métodos: Estudio longitudinal de una cohorte prospectiva a las que se le realiza cirugía conservadora seguida de radiofrecuencia, y una cohorte retrospectiva a las que se le realiza cirugía conservadora sin aplicación de radiofrecuencia. Análisis descriptivo de los resultados y comparativo del grupo a estudio respecto a grupo control. Resultados: Se ha realizado ARF a un total de 14 pacientes, con el empleo de un terminal de electrodo simple, lo que aporta gran versatilidad y reproducibilidad a la técnica, y obteniendo un 100% de márgenes libres. Se ha registrado una reintervención por microcalcificaciones evidenciadas en mamografía de control. No se han registrado complicaciones específicas de la técnica. Se han obtenido un total de 92,8% de resultados buenos ó excelentes. En el análisis comparativo, no se han encontrado diferencias estadísticamente significativas respecto a tasa de reintervenciones, resultados cosméticos ó complicaciones. Conclusiones: 1. La ARF ha demostrado en el grupo de estudio una eficacia del 100% en relación con negatividad o no viabilidad de células tumores en todos los márgenes extirpados. 2. La ARF contribuye a aumentar el margen quirúrgico oncológico de seguridad en cirugía conservadora del cáncer de mama, hecho de especial interés en subgupos de mayor riesgo de recurrencia local. 3. La ARF ha demostrado ser una técnica segura con una tasa de complicaciones generales similares al tratamiento estándar, no existiendo en nuestra serie ninguna complicación específica atribuible a la técnica. 4. La elección del terminal con electrodo simple nos permite mayor versatilidad, adaptando el procedimiento y técnica quirúrgica según el tamaño de la lesión para conseguir el efecto deseado. 5. Asimismo la utilización del terminal con electrodo simple nos permite ampliar indicaciones de la ARF al poder incluir lesiones cercanas a piel y pectoral sin riesgo de quemaduras. 6. La aplicación de radiofrecuencia en márgenes y su exéresis no ha afectado el resultado cosmético.