Monografía de las aguas sulfo, selénido hídricas, arseniadas, bicarbonatadas alcalino-térreo, metálicas de Carratraca /

Mode of access: Internet.

Técnicas de conformação de feixe em arranjo de antenas utilizando aprendizagem por reforço

Beamforming is a technique widely used in various fields. With the aid of an antenna array, the beamforming aims to minimize the contribution of unknown interferents directions, while capturing the desired signal in a given direction. In this thesis are proposed beamforming techniques using Reinforcement Learning (RL) through the Q-Learning algorithm in antennas array. One proposal is to use RL to find the optimal policy selection between the beamforming (BF) and power control (PC) in order to better leverage the individual characteristics of each of them for a certain amount of Signal to Interference plus noise Ration (SINR). Another proposal is to use RL to determine the optimal policy between blind beamforming algorithm of CMA (Constant Modulus Algorithm) and DD (Decision Direct) in multipath environments. Results from simulations showed that the RL technique could be effective in achieving na optimal of switching between different techniques.

Utilização do titâneo na confecção de estruturas metálicas em prótese parcial removível

Due to properties such as excellent biocompatibility, high resistance to corrosion and low specific weight, titanium has been considered a material of great interest for Dentistry. It has been widely used in implants and orthognathic surgeries. Recently, titanium has been seen as a feasible alternative for the fabrication of removable partial denture frameworks, either in pure titanium (99.75%) or in titanium alloy forms (Ti-6Al-4V; Ti-6A1-7Nb). Based on a review of the literature, this work studied the use of titanium for the fabrication of removable partial denture frameworks, focusing on its advantages and disadvantages as well as its characteristics. It was concluded that the use of titanium is a convenient option for partially edentulous arches rehabilitation with quite satisfactory and promising clinical results. However, the need for highly-equipped laboratories increases the cost, preventing its large scale use.

Utilização do titâneo na confecção de estruturas metálicas em prótese parcial removível

Due to properties such as excellent biocompatibility, high resistance to corrosion and low specific weight, titanium has been considered a material of great interest for Dentistry. It has been widely used in implants and orthognathic surgeries. Recently, titanium has been seen as a feasible alternative for the fabrication of removable partial denture frameworks, either in pure titanium (99.75%) or in titanium alloy forms (Ti-6Al-4V; Ti-6A1-7Nb). Based on a review of the literature, this work studied the use of titanium for the fabrication of removable partial denture frameworks, focusing on its advantages and disadvantages as well as its characteristics. It was concluded that the use of titanium is a convenient option for partially edentulous arches rehabilitation with quite satisfactory and promising clinical results. However, the need for highly-equipped laboratories increases the cost, preventing its large scale use.

Análise do uso de escalas nas simulações de processos de estampagem

The purpose of using software based on numerical approximations for metal forming is given by the need to ensure process efficiency in order to get high quality products at lowest cost and shortest time. This study uses the theory of similitude in order to develop a technique capable of simulating the stamping process of a metal sheet, obtaining results close to the real values, with shorter processing times. The results are obtained through simulations performed in the finite element software STAMPACK®. This software uses the explicit integration method in time, which is usually applied to solve nonlinear problems involving contact, such as the metal forming processes. The technique was developed from a stamping model of a square box, simulated with four different scale factors, two higher and two smaller than the real scale. The technique was validated with a bending model of a welded plate, which had a high simulation time. The application of the technique allowed over 50% of decrease in the time of simulation. The results for the application of the scale technique for forming plates were satisfactory, showing good quantitative results related to the decrease of the total time of simulation. Finally, it is noted that the decrease in simulation time is only possible with the use of two related scales, the geometric and kinematic scale. The kinematic scale factors should be used with caution, because the high speeds can cause dynamic problems and could influence the results of the simulations.

Desenvolvimento de uma técnica para análise de desgaste em peças metálicas com o uso do ciclotron CV-28 do IEN

As técnicas nucleares, com ênfase a técnica conhecida como TLA - Thin Layer Activation, tem sido utilizada com sucesso e contribuído significativamente para o estudo de sistemas tribológicos, na análise e medição de desgaste para profundidades na ordem de grandeza de 10 µm apesar potencialmente poder aplicadas a espessuras de dezenas de milímetros. Esta limitação é intrínseca da técnica utilizada na ativação da camada superficial da peça ou elemento a ser investigado, que consiste na aplicação direta de um feixe de partículas carregadas a uma determinada energia, equivalente a máxima seção de choque do material a fim de obter uma taxa ativação constante ao longo de uma determinada espessura ou utilizando uma energia menor que este valor para se obter uma taxa ativação linear também para uma determinada profundidade de ativação. O objetivo desse trabalho é apresentar uma nova técnica que consiste na utilização de um feixe de energia superior a energia correspondente à máxima seção de choque e aplicar um elemento degradador (Roda Degradadora) como objetivo de homogeneizar a ativação superficial ao longo da espessura da amostra, possibilitando uma melhoria na precisão da análise e possibilitando ainda um maior alcance dessa camada e aumentando a gama de aplicações possíveis dessa técnica, onde por exemplo, maiores taxas de desgaste possam ser analisadas. Após o experimento e análise dos dados constatou-se que a técnica proposta melhora a linearidade da curva que representa a taxa de ativação e aumentando significativamente a profundidade analisável podendo chegar a ordem 6 x 10 µm. Em adição este trabalho reinaugura a pesquisa em aplicações nucleares no IEN - Instituto de Engenharia Nuclear com utilização de aceleradores de partículas tipo ciclotron.

Tintado de superficies y efectos visuales mediante el uso de micro y nanopartículas metálicas

Sistema de coloración de superficies mediante el empleo de soluciones de partículas nanoscópicas metálicas depositadas sobre la superficie del objeto a tintar. Al no suponer un recubrimiento completo de la superficie, como el que se da en depósitos moleculares, sino un depósito discreto de partículas, dejará pasar los detalles originales de la superficie. Este método presenta la ventaja de que el color se controla mediante la elección del tipo de partícula o mezcla de ellas y no únicamente mediante el control del espesor de la lámina depositada, en el caso de deposiciones moleculares. Lo parámetros de control y diseño son: forma de las partículas, tamaño de las partículas, relación de aspecto de las mismas, naturaleza material de las partículas, concentración de partículas, relación de mezcla de las partículas.

Caminhos que estruturam cidades: redes técnicas de transporte sobre trilhos e a conformação intra-urbana de Natal

The railroad, from 1870 and on, becomes an usual complaining in the press s and politician elite s speeches, especially because of Natal s geographic isolation. The implantation of two railroads in the capital territory Estrada de Ferro de Natal a Nova Cruz, afterwards part of Great Western Railway Company network, and Estrada de Ferro Central do Rio Grande do Norte had serious implications in the urban environment. While railroad s structures were already consolidated, other transportation mechanisms were being implanted in the first decades of the 20th century, such as trams lines, which, by the way, was a transport modal that also used rails as a dislocation meaning. Considering these questions, we may ask: how come railroads and tramways demands, roads and buildings had influenced the internal organization of Natal? We work with the general hypothesis that the influence of technical networks, composed by tramways and railroads, over Natal s urban space happened in a diversified way, sometimes consolidating social aspects in certain areas, sometimes improving the occupation of others. The impact over the city s territory also happens in a diversified way between the buildings/railroad s complexes and the pathways. The different scale of the train in comparison to the trams velocity, size, noise level, flow, among others is also a cause to the different consequences in urban environment. The main objective of this work is to understand the role of circulation technical networks in the construction process of urban space in Natal, as a way to contribute to the urban historiography about the subject. The time frame adopted, between 1881 and 1937, marks the time path of railroads and tramways in Rio Grande do Norte: 1881 is the year of railroad s first section inauguration from Natal to São José do Mipibu as well of the railroad complex in the Republic Square in Natal; the year of 1937 marks the beginning of tramways declination process in the city. At this time railroads and tramways had to face more intensively the competition of motor vehicles. The theory reference adopted is based on concepts and analysis of authors, such as Flávio Villaça and Roberto Lobato Corrêa references to the concepts of urban structure , localization and accessibility and Gabriel Dupuy to explain the concept of urban technical networks . These references reveal the conflict of different realities in the urban universe interests and values which is an important factor about the construction of urban space. The information sources used were from two distinctive natures: primary, journals of the time studied and official government reports, and secondary, based on other works about the subject. It was also used by this study iconographic source, especially images from the data base of the research group História da Cidade, do Território e do Urbanismo .

Caracterização elementar de ligas metálicas em implantes dentários

An ideal biomaterial for dental implants must have very high biocompatibility, which means that such materials should not provoke any serious adverse tissue response. Also, used metal alloys must have high fatigue resistance due the masticatory force and good corrosion resistance. These properties are rendered by using alpha and beta stabilizers, such as Al, V, Ni, Fe, Cr, Cu, Zn. Commercially pure titanium (TiCP) is used often for dental and orthopedic implants manufacturing. However, sometimes other alloys are employed and consequently it is essential to research the chemical elements present in those alloys that could bring prejudice for the health. Present work investigated TiCP metal alloys used for dental implant manufacturing and evaluated the presence of stabilizing elements within existing limits and standards for such materials. For alloy characterization and identification of stabilizing elements it was used EDXRF technique. This method allows to perform qualitative and quantitative analysis of the materials using the spectra of the characteristic X-rays emitted by the elements present in the metal samples. The experimental setup was based on two X- rays tubes (AMPTEK Mini X model with Ag and Au targets), a X-123SDD detector (AMPTEK) and a 0.5mm Cu collimator, developed due to the sample characteristics. The other experimental setup used as a complementary technique is composed of an X-ray tube with a Mo target, collimator 0.65mm and XFlash (SDD) detector - ARTAX 200 (BRUKER). Other method for elemental characterization by energy dispersive spectroscopy (EDS) applied in present work was based on Scanning Electron Microscopy (SEM) EVO® (Zeeis). This method also was used to evaluate the surface microstructure of the sample. The percentual of Ti obtained in the elementary characterization was among 93.35 ± 0.17% and 95.34 ± 0.19 %. These values are considered below the reference limit of 98.635% to 99.5% for TiCP, established by Association of metals centric materials engineers and scientists Society (ASM). The presence of elements Al and V in all samples also contributed to underpin the fact that are not TiCP implants. The values for Al vary between 6.3 ± 1.3% and 3.7 ± 2.0% and for V, between 0.26 ± 0.09% and 0.112 ± 0.048%. According to the American Society for Testing and Materials (ASTM), these elements should not be present in TiCP and in accordance with the National Institute of Standards and Technology (NIST), the presence of Al should be <0.01% and V should be of 0.009 ± 0.001%. Obtained results showed that implant materials are not exactly TiCP but, were manufactured using Ti-Al-V alloy, which contained Fe, Ni, Cu and Zn. The quantitative analysis and elementary characterization of experimental results shows that the best accuracy and precision were reached with X-Ray tube with Au target and collimator of 0.5 mm. Use of technique of EDS confirmed the results of EDXRF for Ti-Al-V alloy. Evaluating the surface microstructure by SEM of the implants, it was possible to infer that ten of the thirteen studied samples are contemporaneous, rough surface and three with machined surface.

Programa de seguridad y salud ocupacional para las pequeñas empresas de estructuras metálicas del municipio de San Martín: Caso ilustrativo.

La seguridad y salud ocupacional tiene como finalidad principal velar para que las condiciones de los trabajadores sean óptimas para desarrollar sus actividades; que el lugar donde se desempeñen proporcione el más alto grado de bienestar físico, mental y social. De igual manera se hace necesaria la identificación de los riesgos a los que se exponen dichos trabajadores, para tratar de eliminarlos o minimizarlos lo más que se pueda. De ahí el objetivo principal de esta investigación; ya que para esto se hace necesario contar con un programa de seguridad y salud ocupacional, que sirva de guía de acción ante eventualidades que pueden surgir en las actividades diarias de una empresa; de igual manera sirve para poder identificar los accidentes y enfermedades más comunes, identificaciones de riesgos y las acciones correctivas para prevenirlos, es decir dentro del programa de seguridad y salud ocupacional se encuentra todos esos lineamientos necesarios para poder brindarle a los trabajadores las mejores condiciones en su lugar de trabajo. Para realizar la investigación de campo se utilizaron técnicas e instrumentos de investigación necesario que fueran capaces de poder recolectar la información necesaria, utilizando fuentes primarias y secundarias, así como la observación directa, entrevistas y encuestas; todo esto con el fin de obtener la información necesaria para poder hacer un diagnóstico sobre la situación en la que se encuentran las pequeñas empresas en lo referido a la seguridad y salud ocupacional. Las principales conclusiones a las que se llegaron es que las pequeñas empresas dedicadas a la fabricación de estructuras metálicas del municipio de San Martin no cuentan con un Programa de Seguridad y Salud Ocupacional y que la mayoría de empleados desconocen sobre este tema, por lo que se recomendó el diseño de un Programa de Seguridad y Salud ocupacional así como también la creación de un Comité de Seguridad y Salud ocupacional. Finalmente se realizó la creación del Programa se Seguridad y Salud ocupacional para la empresa “El Detalle”, en donde se establecen los lineamientos a seguir para que se mejoren las condiciones en las que los empleados realicen sus actividades, dicho programa puede servir como guía también para las demás pequeñas empresas de estructuras metálicas.