Modelling and Administration of Contract-Based Systems

Mirroring the paper versions exchanged between businesses today, electronic contracts offer the possibility of dynamic, automatic creation and enforcement of restrictions and compulsions on agent behaviour that are designed to ensure business objectives are met. However, where there are many contracts within a particular application, it can be difficult to determine whether the system can reliably fulfil them all; computer-parsable electronic contracts may allow such verification to be automated. In this paper, we describe a conceptual framework and architecture specification in which normative business contracts can be electronically represented, verified, established, renewed, etc. In particular, we aim to allow systems containing multiple contracts to be checked for conflicts and violations of business objectives. We illustrate the framework and architecture with an aerospace example.

Electronic Business Contracts between Services

Electronic contracts mirror the paper versions exchanged between businesses today, and offer the possibility of dynamic, automatic creation and enforcement of restrictions and compulsions on service behaviour that are designed to ensure business objectives are met. Where there are many contracts within a particular application, it can be difficult to determine whether the system can reliably fulfil them all, yet computer-parsable electronic contracts may allow such verification to be automated. In this chapter, we describe a conceptual framework and architecture specification in which normative business contracts can be electronically represented, verified, established, renewed, and so on. In particular, we aim to allow systems containing multiple contracts to be checked for conflicts and violations of business objectives. We illustrate the framework and architecture with an aerospace aftermarket example.

Verdi's Settings of Shakespeare : from Play to Liberetto to Opera

As a Senior Scholar pursuing the topic, Verdi's Settings of Shakespeare: From Play to Libretto to Opera, I have endeavoured to study a project relevant to my majors, Music and English. During first semester, I carefully analysed Shakespeare's plays, Macbeth, Othello and Falstaff. The highlight of my project was in January when I travelled to New York City and spent the day working with the Metropolitan Opera Guild. I was also able to see a performance of Verdi's Othello with Jon Vickers in the lead role. During the second semester, I studied the musical aspects of the compositions. I spent time analysing musical passages and relating them to the plays and the operas. I was also able to continue my study of Italian, which I find extremely beneficial while studying Verdi's libretti. On Monday, 13th May, 1974, I gave a lecture presentation of my project. At this time, I showed slides of Metropolitan productions of the operas, presented my own rendition of five arias (in costume) and talked about comparisions between the plays and the operas. I applied for a Rotary Fellowship to take my project to Europe and am presently waiting to hear the results. If I do receive the fellowship, I am planning to spend a year studying the plays and operas in England and Italy. Afterwards, I hope to publish a paper explaining my findings. The paper is divided into six sections. The first section is an introduction which explains the period of Romanticism and its relationship to Shakespeare and Verdi. The second section is devoted to discussing the librettist for Macbeth, Francesco Piave. Following this section the opera Macbeth is discussed. Arrigo Boito, the librettist for Otello and Falstaff is discussed in the fourth section. The last two sections deal with Otello and Falstaff. I have also included a number of musical selections to better explain certain passages. My project has been invaluable to me. My Senior Scholar project has allowed me the freedom of independent study as well as a means of tying my majors together.

A implementação de uma política pública em área metropolitana: transporte coletivo em São Paulo 1981-1989

Trata da formação e implementação das políticas de Transporte urbano na região Metropolitana de São paulo, na década de 80, como resultado da articulação entre agentes. A análise é feita sob prisma de como foram conduzidas as políticas públicas na transição democrática

As teorias keynesianas do investimento

O objetivo da dissertação é analisar as principais teorias keynesianas do investimento desenvolvidas no pós-gerra, tendo em vista a característica das decisões de investimento, e finalmente em uma linha que podemos denominar de fundamentalista ou pós-keynesiana, isto é, admitindo explicitamente a incerteza, se considerará o modelo de Shackle-Vickers como uma alternativa aos modelos baseados em uma racionalidade econômica convencional.

Obtenção de superligas NiCrAIY nanoestruturadas por moagem de alta energia e sua aplicação por aspersão térmica hipersônica (HVOF)

Esta dissertação tem como objetivos o estudo da produção de uma liga metálica nanoestruturada através do processo de moagem de alta energia, determinar a evolução microestrutural desta liga metálica durante o seu processamento e sua utilização na forma de revestimento protetor, depositado por aspersão térmica HVOF. O material escolhido foi a superliga NiCrAlY devido a sua grande importância tecnológica e pela pequena quantidade de trabalhos publicados até o momento sobre a produção e o emprego desta liga na forma nanoestruturada. A superliga NiCrAlY foi processada através de um moinho de alta energia do tipo Szegvari, empregando-se esferas de aço AISI 52100 como meio de moagem, em 3 diferentes condições de agitação e 3 relações entre meio de moagem/material. O material processado foi caracterizado através de diferentes métodos de análise, segundo critérios como: i) morfologia, caracterizada através de microscopia eletrônica de varredura e granulometria por difração de laser, ii) tamanho de cristalito, através da análise do alargamento dos picos de difração de raios X pelo método single-line, iii) nível de contaminação por Fe, determinado através da análise por fluorescência de raios X. Revestimentos protetores foram depositados através do processo de aspersão térmica HVOF sobre substratos de aço inox AISI 304 para o estudo dos parâmetros de deposição e controle microestrutural dos revestimentos, com o objetivo de manter o tamanho de cristalito nanométrico das partículas após a deposição Os resultados mostram que o processo de moagem de alta energia provoca uma profunda alteração na morfologia das partículas, originando partículas achatadas e pequenos fragmentos, além de uma rápida redução do tamanho de cristalito, atingindo valores menores do que 20 nm nas primeiras horas de processamento. A microestrutura dos revestimentos depositados apresenta-se com um caráter lamelar acentuado, devido ao formato pré-aspersão das partículas, e uma microestrutura densa com uma quantidade relativamente grande de óxidos interlamelares. Também foi constatado que o processo de deposição dos revestimentos por aspersão térmica HVOF leva a um crescimento no tamanho dos cristalitos das partículas, mas é capaz de manter o tamanho dos cristalitos inferior a 100 nm após a deposição, levando a um revestimento com microdureza Vickers 35% superior com relação ao revestimento depositado com o material convencional.

Análise por difração de raios-x da interface plasma-superfície durante a nitretação a plasma

O presente trabalho apresenta o desenvolvimento de um equipamento utilizado para acompanhamento e monitoramento do processo de nitretação a plasma enquanto ele ocorre, ou seja, de forma in-situ. Os resultados obtidos com a utilização deste equipamento são demonstrados e confirmam a potencialidade da técnica na caracterização de mecanismos de nitretação a plasma. Ensaios de adaptação à técnica foram realizados, visando adquirir experiência no reconhecimento e detecção de fases formadas durante o processo e de possibilidades de caracterização proporcionadas pela técnica. Desta forma a influência de três composições gasosas na formação de camadas nitretadas em aço médio carbono AISI 1045 foi avaliada de forma in-situ por difração de raios-X e post-mortem por metalografia, GDOS e microdureza Vickers. A composição gasosa de 76% N2 – 24% H2 mostrou alto poder de nitretação, e formou camadas de compostos espessas e zonas de difusão profundas, com aumentos consideráveis de dureza. A composição gasosa de 5% N2 – 95% H2, formou camadas de compostos pequenas e zonas de difusão profundas, além de aumentos de dureza superficial. Em uma segunda avaliação, amostras de aço AISI 1045, foram nitretadas em duas composições gasosas: 5% N2 – 95% H2 e 25% N2 – 75% H2, nas temperaturas de 450ºC, 480ºC, 520ºC, 540ºC e 560ºC. Com o acompanhamento in-situ por difração de raios-X de trechos específicos de 2Θ correspondentes às linhas de difração das fases γ’ e ε, foi possível obter o tempo de incubação da fase γ’ para cada combinação composição gasosa - temperatura, que foram comparados com dados já existentes para nitretação a gás. Também foi possível o acompanhamento do crescimento, desenvolvimento e de mudanças na largura das linhas destas fases O tempo de incubação da fase γ’ permitiu a comparação entre os resultados das nitretações a plasma e os resultados previstos por um diagrama de Lehrer, e uma boa correlação entre as fases previstas pelo diagrama e as encontradas na prática foi encontrada. As amostras foram avaliadas ainda por difração de raios-X em ângulos rasantes, que permitiu a caracterização das camadas mais superficiais das amostras e, com base nestes resultados e nos resultados das análises in-situ, obteve-se um mapa prático de previsão de fases para a nitretação a plasma.

Estudo da zircônia reforçado com alumina

Ceramics materials have good properties including chemical stability, high hardness and wear resistance. Moreover, due to its fragility, can suffer failure under relatively low levels of tension. Actually zirconia is the material of choice in metal free dental prostheses used in dentistry due its inertia in physiological environment, good bending strength, hardness and fracture toughness. The alumina and mixed tungsten and titanium carbides additions, acting as reinforcement elements in the zirconia matrix, have as their main objective the improvement of mechanical properties of this material. In this work, samples of zirconia, zirconia with 30% wt of alumina and zirconia with 30% wt mixed carbides were analyzed. The samples were sintered by uniaxial hot pressing on 30 MPa pressure, for 1 hour in an argon atmosphere. They were physically characterized by porosity and density measurements, and mechanically by 3-points bending strength and Vickers microhardness. The X-ray diffraction was used for the phase identifications and microstructure was examined by scanning electron microscopy (SEM). The addition of mixed carbides as reinforcement elements in zirconia matrix provides improvements in all properties analyzed in this work. The alumina addition has dropped the zirconia strength, although it caused improvement in other properties

Caracterização de compósitos Nb-20%cu obtidos por moagem de alta energia e sinterizados por fase líquida

In this work, was studied the formation of a composite of the refractory metal niobium with copper, through the process of high-energy milling and liquid phase sintering. The HEM can be used to synthesize composite powders with high homogeneity and fine size particle distribution. It may also produce the solid solubility in immiscible systems such as Nb-Cu, or extend the solubility of systems with limited solubility. Therefore, in the immiscible system Cu-Nb, the high-energy milling was successfully used to obtain the composite powder particles. Initially, the formation of composite particles during the HEM and the effect of preparation technique on the microstructure of the material was evaluated. Four loads of Nb and Cu powders containing 20%wt Cu were synthesized by MAE in a planetary type ball mill under different periods of grinding. The influence of grinding time on the metal particles is evaluated during the process by the withdrawal of samples at intermediate times of milling. After compaction under different forces, the samples were sintered in a vacuum furnace. The liquid phase sintering of these samples prepared by HEM produced a homogeneous and fine grained. The composite particles forming the sintered samples are the addition of a hard phase (Nb) with a high melting point, and a ductile phase (Cu) with low melting point and high thermal and electrical conductivities. Based on these properties, the Nb-Cu system is a potential material for many applications, such as electrical contacts, welding electrodes, coils for generating high magnetic fields, heat sinks and microwave absorbers, which are coupled to electronic devices. The characterization techniques used in this study, were laser granulometry, used to evaluate the homogeneity and particle size, and the X-ray diffraction, in the phase identification and to analyze the crystalline structure of the powders during milling. The morphology and dispersion of the phases in the composite powder particles, as well the microstructures of the sintered samples, were observed by scanning electron microscopy (SEM). Subsequently, the sintered samples are evaluated for density and densification. And finally, they were characterized by techniques of measuring the electrical conductivity and microhardness, whose properties are analyzed as a function of the parameters for obtaining the composite

Estudo sobre o efeito dos parâmetros de processamento dos pós e sinterização do aço inox 316l reforçado com NbC

This masther dissertation presents a contribution to the study of 316L stainless steel sintering aiming to study their behavior in the milling process and the effect of isotherm temperature on the microstructure and mechanical properties. The 316L stainless steel is a widely used alloy for their high corrosion resistance property. However its application is limited by the low wear resistance consequence of its low hardness. In previous work we analyzed the effect of sintering additives as NbC and TaC. This study aims at deepening the understanding of sintering, analyzing the effect of grinding on particle size and microstructure and the effect of heating rate and soaking time on the sintered microstructure and on their microhardness. Were milled 316L powders with NbC at 1, 5 and 24 hours respectively. Particulates were characterized by SEM and . Cylindrical samples height and diameter of 5.0 mm were compacted at 700 MPa. The sintering conditions were: heating rate 5, 10 and 15◦C/min, temperature 1000, 1100, 1200, 1290 and 1300◦C, and soaking times of 30 and 60min. The cooling rate was maintained at 25◦C/min. All samples were sintered in a vacuum furnace. The sintered microstructure were characterized by optical and electron microscopy as well as density and microhardness. It was observed that the milling process has an influence on sintering, as well as temperature. The major effect was caused by firing temperature, followed by the grinding and heating rate. In this case, the highest rates correspond to higher sintering.

Adição de nanopartículas de Ti em matriz de Fe através da deposição por magnetron sputtering

Microalloyed steels constitute a specific class of steel with low amount of carbon and microalloying elements such as Vanadium (V), Niobium (Nb) and Titanium (Ti). The development and application of microalloyed steels and steels in general are limited to the handling of powders with particles of submicron or nanometer dimensions. Therefore, this work presents an alternative in order to construction of microalloyed steels utilizing the deposition by magnetron sputtering technique as a microalloying element addiction in which Ti nanoparticles are dispersed in an iron matrix. The advantage of that technique in relation to the conventional metallurgical processes is the possibility of uniformly disperse the microalloying elements in the iron matrix. It was carried out deposition of Ti onto Fe powder in high CH4, H2, Ar plasma atmosphere, with two deposition times. After the deposition, the iron powder with nanoparticles of Ti dispersed distributed, were compacted and sintered at 1120 ° C in resistive furnace. Characterization techniques utilized in the samples of powder before and after deposition of Ti were Granulometry, Scanning Electron Microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (DRX). In the case of sintered samples, it was carried out characterization by SEM and Vickers Microhardness assays. The results show which the deposition technique by magnetron sputtering is practicable in the dispersion of particles in iron matrix. The EDX microanalysis detected higher percentages of Ti when the deposition were carried out with the inert gas and when the deposition process was carried out with reactive gas. The presence of titanium in iron matrix was also evidenced by the results of X-ray diffraction peaks that showed shifts in the network matrix. Given these results it can be said that the technique of magnetron sputtering deposition is feasible in the dispersion of nanoparticles of iron matrix in Ti.

Estudo da sinterabilidade de ligas de níquel obtidas por meio dos portadores de liga sic, si3n4 ou si metálico com grafita

Nickel alloys are frequently used in applications that require resistance at high temperatures associated with resistance to corrosion. Alloys of Ni-Si-C can be obtained by means of powder metallurgy in which powder mixtures are made of metallic nickel powders with additions of various alloying carriers for such were used in this study SiC, Si3N4 or Si metal with graphite. Carbonyl Ni powder with mean particle size of 11 mM were mixed with 3 wt% of SiC powders with an average particle size of 15, 30 and 50 μm and further samples were obtained containing 4 to 5% by mass of SiC with average particle size of 15 μm. Samples were also obtained by varying the carrier alloy, these being Si3N4 powder with graphite, with average particle size of 1.5 and 5 μm, respectively. As a metallic Si graphite with average particle size of 12.5 and 5 μm, respectively. The reference material used was nickel carbonyl sintered without adding carriers. Microstructural characterization of the alloys was made by optical microscopy and scanning electron microscopy with semi-quantitative chemical analysis. We determined the densities of the samples and measurement of microhardness. We studied the dissociation of carriers alloy after sintering at 1200 ° C for 60 minutes. Was evaluated also in the same sintering conditions, the influence of the variation of average particle size of the SiC carrier to the proportion of 3% by mass. Finally, we studied the influence of variation of the temperatures of sintering at 950, 1080 and 1200 ° C without landing and also with heights of 30, 60, 120 and 240 minutes for sintering where the temperature was 950 °C. Dilatometry curves showed that the SiC sintered Ni favors more effectively than other carriers alloy analyzed. SiC with average particle size of 15 μm active sintering the alloy more effectively than other SiC used. However, with the chemical and morphological analyzes for all leagues, it was observed that there was dissociation of SiC and Si3N4, as well as diffusion of Si in Ni matrix and carbon cluster and dispersed in the matrix, which also occurred for the alloys with Si carriers and metallic graphite. So the league that was presented better results containing Si Ni with graphite metallic alloy as carriers, since this had dispersed graphite best in the league, reaching the microstructural model proposed, which is necessary for material characteristic of solid lubricant, so how we got the best results when the density and hardness of the alloy

Revestimentos a base de Ta/Al2O3 produzidos por aspersão térmica sobre substrato metálico

Metal substrates were coated by thermal spraying plasma torch, they were positioned at a distance of 4 and 5 cm from the nozzle exit of the plasma jet. The starting materials were used for deposition of tantalum oxide powder and aluminium. These two materials were mixed and ground into high-energy mill, then immersed in the torch for the production of alumina coating infused with particles of tantalum with nano and micrometric size. The spraying equipment used is a plasma torch arc not transferred, which operating in the range of 250 A and 80 V, was able to produce enough heat to ignite aluminothermic between Ta2O5 and aluminum. Upon reaching the plasma jet, the mixing powders react with the heat of the blaze, which provides sufficient energy for melting aluminum particles. This energy is transferred through mechanisms of self-propagating to the oxide, beginning a reduction reaction, which then hits on the surface of the substrate and forms a coating on which a composite is formed by a junction metal - ceramic (Ta +Al2O3). The phases and quantification of each were obtained respectively by X-ray diffraction and the Rietveld method. Morphology by scanning electron microscopy and chemical analysis by energy dispersive spectroscopy EDS. It was also performed measurements of the substrate roughness, Vickers microhardness measurements in sprays and determination of the electron temperature of the plasma jet by optical emission spectroscopy EEO. The results confirmed the expectation generated around the end product of spraying the mixture Ta2O5 + Al, both in the formation of nano-sized particles and in their final form. The electron excitation temperature was consistent with the purpose of work, in addition, the thermodynamic temperature was efficient for the reduction process of Ta2O5. The electron excitation temperature showed values of 3000, 4500 and 8000 K for flows10, 20 and 30 l / min respectively, these values were taken at the nozzle exit of the plasma jet. The thermodynamic temperature around 1200 ° C, was effective in the reduction process of Ta2O5

Estudo da viabilidade técnica para obtenção de superfície duplex em aço inoxidável martensítico AISI 410 através do processo de deposição a plasma por gaiola catódica

The technique of plasma nitriding by the cathode cage mainly stands out for its ability to produce uniform layers, even on parts with complex geometries. In this study, it was investigated the efficiency of this technique for obtaining duplex surface, when used, simultaneously, to nitriding treatment and thin film deposition at temperatures below 500°C. For this, were used samples of AISI 41 0 Martensitic Stainless Steel and performed plasma treatment, combining nitriding and deposition of thin films of Ti and/or TiN in a plasma atmosphere containing N2-H2. It was used a cathodic cage of titanium pure grade II, cylindrical with 70 mm diameter and 34 mm height. Samples were treated at temperature 420ºC for 2 and 12 hours in different working pressures. Optical Microscopy (OM), Scanning Electron Microscopy (SEM) with micro-analysis by Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and analysis of Vickers Microhardness were used to investigate coating properties such as homogeneity and surface topography, chemical composition, layer thickness, crystalline phase, roughness and surface microhardness. The results showed there is a direct proportionality between the presence of H2 in plasma atmosphere and the quantity of titanium in surface chemical composition. It was also observed that the plasma treatment at lowpressure is more effective in formation of TiN thin film