Avaliação tribológica de novas modificações superficiais para cilindros de laminação a frio

The present work analyzed the tribological behavior of coatings/surface modifications traditionally used in cold rolling mill rolls and new coatings/surface modificationswith potential to replace the carcinogenic hard chrome. The study started with identification of wear mechanisms occurring in real coldrollingmill rolls. Due the high cost and dimensions of the rolls, thereplication technique was used. Replicas were obtained from 4 different rolling millBrazilian companies before and after a normal rolling campaign. Initial sliding tests were conducted using spherical and cylindrical counter bodies in order to verifywhichtribological conditions allowed to reproduce the wear mechanisms found in the replicas. These tests indicated the use of reciprocating sliding tests with cylindrical counter bodies (line contact), normal load of 100 N, and test times of and 1 h and 5 h. Different surface modifications were carried out on samples produced from a fragment of a rolling mill roll. The specimens were heat treated and ground on both sides. After, some specimens were surface textured by electrical discharge texturing (EDT). For both groups (ground and EDT), subsequent treatments of chromium plating, electroless NiP coating and plasma nitriding were carried out. The results of the reciprocating tests showed that specimens with electroless NiP coating presented the lowest friction coefficients, while plasma nitrided specimens showed the highest. In general, previous surface texturing before the coating/surface modification increased the wear of the counter bodies. Oneexceptionwas for EDT with subsequent electroless NiP coating, which presented the lowest counter bodies wear rate. The samples withelectroless NiP coating promoted a tribolayer consisting of Nickel, Phosphorus and Oxygen on both the specimens andthecounter bodies, which was apparently responsible for the reduction of friction coefficient and wear rate. The increase of the test time reduced the wear rate of the samples, apparently due the stability of the tribolayers formed, except for the nitrided samples. For the textured specimens, NiP coating showed the best performance in maintaining the surface topography of the specimens after the sliding tests.

Território, Criminalidade e tráfico de drogas ilícitas em Montes Claros/MG

Urban violence, manifestly public and free, has changed the standard of sociability of townspeople. The city is an increasingly private space of hopes of reducing the risk of victimization, due to the fear of violence that separates and distances the classes in expectation of concealing this behavior. However, violence has many facets and, in one way or another, will always be present as a product of social friction. It is in the urban context and using drug trafficking as a backdrop that this work raises questions about the territorial violence in Montes Claros - MG. The objective was to analyze the dynamics of illicit drug trafficking from the concepts of territory, observing to what extent the appropriation of space contributes to the use of violence, especially in interpersonal disputes. Methodologically, it seeks from quantitative and qualitative techniques make the spatial distribution of criminal indicators, defining and creating hierarchy territories of violence in urban areas. From the qualitative approach seeks to organize and analyze data together to the Civil and Military Police, Brazilian Institute of Geography and Statistics -IBGE, João Pinheiro Foundation and the System of the Ministry of Health Mortality Information - SIM. The opportunity of miscegenation between the knowledge of the survey respondents and the official data has introduced qualitative part. The city of Montes Claros has been taken as an object of observation due to a set of conditions, which stood its medium size, your importance in the regional context and their socioeconomic disparities. The results point to the existence of multiple territoriality of violence involving the trafficking of illicit drugs in urban space. Territorial disputes by the traffickers have victimized people with socioeconomic characteristics and urban spatial origin similar. The dynamism of the established boundaries from the cohesion and / or rupture of the interests of those involved creates and destroys territories in the power struggle.

Cooperação e competição entre políticas no Brasil: os custos da governabilidade no presidencialismo de coalizão

Public policies have been studied in the various fields of humanities and social sciences, from different theoretical and technical aspects. However, there is still a lack of studies that incorporate the dimension that encompasses the political action and its interference in such actions, also recognizing the importance of the institutional setting of the Brazilian presidential model in implementing these policies. This fragmented and multiparty system has led to power heterogeneous sets of political parties. Thus, the ministerial offices, more than assisting the President´s government project, manage particularized agendas, which are party biased and have the influence of interest groups in hegemonic themes addressed by government agencies. When these agendas operate in sectoral and specialized policies, the friction level is apparently low. However, when this occurs in intersectoral actions, such as in regional development, there is evidence of strong signs of competition among government agencies, which in theory, should operate in an integrated manner. Although this is not a specific feature of Luiz Inacio Lula da Silva´s government- the period to be studied- there was similar behavior in Fernando Henrique Cardoso´s presidency, one realizes that the expansion of coalition on behalf of governance is increasingly interfering in the outcome of intersectoral public policies, due to these multiple arguments in action. In order to understand these processes, this study focused on the Sustainable and Integrated Development Programme for Differentiated Meso-Regions (PROMESO), part of the National Policy for Regional Development (NPRD). The program provides interface with various government agencies and their public policies in a clear intersectoral design. The research sought to identify and analyze the relationships between government agencies and their programs with interest groups, whether political parties or other segments of civil society, highlighting the logic of favoritism, which poses in second place the integration of actions in the intersectoral policies. Therefore, besides the theoretical debate that incorporates several categories of political science, public administration, public policy, geography and economics, the study focused on secondary sources, using different government agencies databases in order to raise information. It was observed that the interference of partisan politics has been disastrous for some public policies. Thus, the research confirms that cooperative character is fragile within government agencies, often limited to official documents, and that there is indeed, a striking feature of competition, especially when it comes to transversalized policies

Efeito da radiação micro-ondas na sinterização em fases sólida e líquida de pós de aço inoxidável 3I6L

Tese submetida à Universidade de Coimbra, Faculdade de Ciências e Tecnologia e aprovada em provas públicas para a obtenção do Grau de Doutor em Engenharia Mecânica (especialidade de Ciência dos Materiais)

Análise e proposição de estratégias de estimação e controle de velocidade para motores de indução trifásicos

This study presents a proposal of speed servomechanisms without the use of mechanical sensors (sensorless) using induction motors. A comparison is performed and propose techniques for pet rotor speed, analyzing performance in different conditions of speed and load. For the determination of control technique, initially, is performed an analysis of the technical literature of the main control and speed estimation used, with their characteristics and limitations. The proposed technique for servo sensorless speed induction motor uses indirect field-oriented control (IFOC), composed of four controllers of the proportional-integral type (PI): rotor flux controller, speed controller and current controllers in the direct and quadrature shaft. As the main focus of the work is in the speed control loop was implemented in Matlab the recursive least squares algorithm (RLS) for identification of mechanical parameters, such as moment of inertia and friction coefficient. Thus, the speed of outer loop controller gains can be self adjusted to compensate for any changes in the mechanical parameters. For speed estimation techniques are analyzed: MRAS by rotóricos fluxes MRAS by counter EMF, MRAS by instantaneous reactive power, slip, locked loop phase (PLL) and sliding mode. A proposition of estimation in sliding mode based on speed, which is performed a change in rotor flux observer structure is displayed. To evaluate the techniques are performed theoretical analyzes in Matlab simulation environment and experimental platform in electrical machinery drives. The DSP TMS320F28069 was used for experimental implementation of speed estimation techniques and check the performance of the same in a wide speed range, including load insertion. From this analysis is carried out to implement closed-loop control of sensorless speed IFOC structure. The results demonstrated the real possibility of replacing mechanical sensors for estimation techniques proposed and analyzed. Among these, the estimator based on PLL demonstrated the best performance in various conditions, while the technique based on sliding mode has good capacity estimation in steady state and robustness to parametric variations.

Violência institucional e responsabilidade profissional na resposta ao abuso sexual de crianças

Apresenta-se como um artigo de construção teórica, no qual se explora teoricamente o conceito de violência institucional na relação com os limites da responsabilidade profissional por omissão ou por incorrecto procedimento profissional. A reflexão é realizada tendo por base a análise do funcionamento do sistema de justiça na articulação com o sistema de protecção na resposta ao crime de abuso sexual intra-familiar de crianças na comarca de Lisboa. Apresenta-se um conjunto sistematizado de factores de atrito, identificados como principais elementos promotores de violência institucional no quadro da intervenção profissional realizada no contexto das entidades sociais de intervenção nos abusos sexuais de crianças, organizados segundo as categorias de dispositivos e procedimentos.

Cooperação e competição entre políticas no Brasil: os custos da governabilidade no presidencialismo de coalizão

Public policies have been studied in the various fields of humanities and social sciences, from different theoretical and technical aspects. However, there is still a lack of studies that incorporate the dimension that encompasses the political action and its interference in such actions, also recognizing the importance of the institutional setting of the Brazilian presidential model in implementing these policies. This fragmented and multiparty system has led to power heterogeneous sets of political parties. Thus, the ministerial offices, more than assisting the President´s government project, manage particularized agendas, which are party biased and have the influence of interest groups in hegemonic themes addressed by government agencies. When these agendas operate in sectoral and specialized policies, the friction level is apparently low. However, when this occurs in intersectoral actions, such as in regional development, there is evidence of strong signs of competition among government agencies, which in theory, should operate in an integrated manner. Although this is not a specific feature of Luiz Inacio Lula da Silva´s government- the period to be studied- there was similar behavior in Fernando Henrique Cardoso´s presidency, one realizes that the expansion of coalition on behalf of governance is increasingly interfering in the outcome of intersectoral public policies, due to these multiple arguments in action. In order to understand these processes, this study focused on the Sustainable and Integrated Development Programme for Differentiated Meso-Regions (PROMESO), part of the National Policy for Regional Development (NPRD). The program provides interface with various government agencies and their public policies in a clear intersectoral design. The research sought to identify and analyze the relationships between government agencies and their programs with interest groups, whether political parties or other segments of civil society, highlighting the logic of favoritism, which poses in second place the integration of actions in the intersectoral policies. Therefore, besides the theoretical debate that incorporates several categories of political science, public administration, public policy, geography and economics, the study focused on secondary sources, using different government agencies databases in order to raise information. It was observed that the interference of partisan politics has been disastrous for some public policies. Thus, the research confirms that cooperative character is fragile within government agencies, often limited to official documents, and that there is indeed, a striking feature of competition, especially when it comes to transversalized policies

Simulação em uso dos pisos de madeira de Eucalyptus sp e Corymbia maculata

A caracterização anatômica, física, mecânica e química da madeira fornece informações importantes para sua melhor utilização. Contudo, para que madeiras se tornem boa opção para o mercado de pisos, adicionalmente é necessária a realização de ensaios que simulem suas reais condições em serviço. Esses ensaios simulam o pisoteio executado pelos sapatos de salto com pequenas áreas de pressão, o arraste e a queda de objetos, a resistência à abrasão da superfície e o atrito oferecido durante o deslocamento de pessoas que caminham sobre ele. Grande dificuldade da seleção de novas madeiras para pisos está na ausência de valores de referência físico-mecânicos. O presente trabalho visou a caracterizar as madeiras de Eucalyptus clöeziana F. Muell, de Eucalyptus microcorys F. Muell e de Corymbia maculata Hook, para as propriedades de densidade básica, retratibilidade, aplicação de carga rolante, de atrito estático e dinâmico, endentação causada por cargas aplicadas em pequenas áreas, impacto da esfera de aço cadente e resistência à abrasão. Foi observado que as madeiras estudadas podem ser utilizadas para a confecção de pisos, de acordo com seus resultados obtidos e por meio de comparações com resultados de literatura.

A Novel integration approach : perturbation studies in vitro using PDK1 inhibitors in glioblastoma multiforme

Os objetivos a atingir em 2020 no que respeita ao processo de investigação e desenvolvimento de medicamentos estão claramente focados na redução em termos temporais na investigação pré-clínica e clínica e na diminuição da taxa de atrito entre as novas moléculas. De forma a atingir estes objetivos, um novo conceito tem sido desenvolvido e aplicado a este complexo e moroso processo, este é a Farmacologia Quantitativa e de Sistemas. Além disso, esta abordagem inovadora pode ser crucial para o tratamento de determinados tipos de tumores cerebrais letais – Glioblastoma Multiforme (GBM) – que permanecem um desafio terapêutico, e por tanto, uma doença com um destino fatal para os doentes. Por estas razões, esta dissertação de mestrado apresenta uma especial relevância, tendo por objetivos avaliar o potencial impacto e importância biológica da variação de parâmetros farmacológicos, para além da potência, no contexto da resposta celular ao fármaco, pela avaliação da perturbação induzida em células do GBM por inibidores do PDK1 e pela realização de uma caracterização multiparamêtrica dose-resposta destas novas moléculas. A presente dissertação assume em Portugal a vanguarda na área da Farmacologia Quantitativa e de Sistemas aplicada ao processo de investigação e desenvolvimento de medicamentos. Em última estância, esta dissertação poderá contribuir para uma melhor previsão dos fármacos durante este processo, significando assim possíveis vantagens para os utentes, indústrias farmacêuticas, institutos de investigação, governo e institutos superiores.

Otimização e análise mecânica de pastas geopoliméricas para uso em poços sujeitos à injeção cíclica de vapor

Oil wells subjected to cyclic steam injection present important challenges for the development of well cementing systems, mainly due to tensile stresses caused by thermal gradients during its useful life. Cement sheath failures in wells using conventional high compressive strength systems lead to the use of cement systems that are more flexible and/or ductile, with emphasis on Portland cement systems with latex addition. Recent research efforts have presented geopolymeric systems as alternatives. These cementing systems are based on alkaline activation of amorphous aluminosilicates such as metakaolin or fly ash and display advantageous properties such as high compressive strength, fast setting and thermal stability. Basic geopolymeric formulations can be found in the literature, which meet basic oil industry specifications such as rheology, compressive strength and thickening time. In this work, new geopolymeric formulations were developed, based on metakaolin, potassium silicate, potassium hydroxide, silica fume and mineral fiber, using the state of the art in chemical composition, mixture modeling and additivation to optimize the most relevant properties for oil well cementing. Starting from molar ratios considered ideal in the literature (SiO2/Al2O3 = 3.8 e K2O/Al2O3 = 1.0), a study of dry mixtures was performed,based on the compressive packing model, resulting in an optimal volume of 6% for the added solid material. This material (silica fume and mineral fiber) works both as an additional silica source (in the case of silica fume) and as mechanical reinforcement, especially in the case of mineral fiber, which incremented the tensile strength. The first triaxial mechanical study of this class of materials was performed. For comparison, a mechanical study of conventional latex-based cementing systems was also carried out. Regardless of differences in the failure mode (brittle for geopolymers, ductile for latex-based systems), the superior uniaxial compressive strength (37 MPa for the geopolymeric slurry P5 versus 18 MPa for the conventional slurry P2), similar triaxial behavior (friction angle 21° for P5 and P2) and lower stifness (in the elastic region 5.1 GPa for P5 versus 6.8 GPa for P2) of the geopolymeric systems allowed them to withstand a similar amount of mechanical energy (155 kJ/m3 for P5 versus 208 kJ/m3 for P2), noting that geopolymers work in the elastic regime, without the microcracking present in the case of latex-based systems. Therefore, the geopolymers studied on this work must be designed for application in the elastic region to avoid brittle failure. Finally, the tensile strength of geopolymers is originally poor (1.3 MPa for the geopolymeric slurry P3) due to its brittle structure. However, after additivation with mineral fiber, the tensile strength became equivalent to that of latex-based systems (2.3 MPa for P5 and 2.1 MPa for P2). The technical viability of conventional and proposed formulations was evaluated for the whole well life, including stresses due to cyclic steam injection. This analysis was performed using finite element-based simulation software. It was verified that conventional slurries are viable up to 204ºF (400ºC) and geopolymeric slurries are viable above 500ºF (260ºC)

Propriedades tribomecânicas de superfícies de titânio carbonitretadas por plasma

Interstitial compounds of titanium have been mainly studied due to the large range of properties acquired when C, N, O and H atoms are added. In this work, surfaces of TiCxNy were produced by thermochemical treatments assisted by plasma with different proportions of Ar + N2 + CH4 gas mixture. The Ar gas flow was fixed in 4 sccm, varying only N2 and CH4 gas flows. During the thermochemical treatment, the plasma was monitored by Optical Emission Spectroscopy (OES) for the investigation of the influence of active species. After treatments, C and N concentration profile, crystalline and amorphous phases were analyzed by Nuclear Reaction (NRA). Besides tribomechanical properties of the Ti surface were studied through the nanohardness measurements and friction coefficient determination. The worn areas were evaluated by profilometry and Scanning Electronic Microscope (SEM) in order to verify the wear mechanism present in each material. It has been seen which the properties like nanohardness and friction coefficient have strong relation with luminous intensity of species of the plasma, suggesting a using of this characteristic as a parameter of process

Física : dinâmica : 2º exemplo

Recurso educativo de apoio à unidade curricular de física

Avaliação da resistência mecânica de material leve utilizando misturas de pedaços de pneus com solo do Distrito Federal

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2016.