Modelo de gerenciamento de estoques de peças de reposição para empresas de transporte urbano de passageiros

This work searches to offer a model to improve spare parts stock management for companies of urban passenger transport by bus, with the consequent progress in their maintenance management. Also known as MRO items (Maintenance, Repair and Operations), these spare parts, according their consumption and demand features, cost, criticity to operation, lead-time, quantity of suppliers, among other parameters, shouldn´t have managed their inventory like normal production items (work in process e final products), that because their features, are managed by more predictable models based, for example, in economic order quantity. In the case specifically of companies of urban passenger transport by bus, items MRO have significant importance in their assets and a bad management of these inventories can cause serious losses to company, leading it even bankrupticy business, in more severe situations which missing spare part provokes vehicles shutdown indefinitely. Given slight attention to the issue, which translates in little literature available about it when compared to that literature about normal items stocks, and due the fact that MRO items be critical to bus urban transport of passengers companies´, it is necessary, so, deepen in this theme searching to give technical and scientific subsidies to companies that work, in many times, empirically, with these so decisive inputs to their business. As a typical portfolio problem, in which there are n items, separated into critical and noncritical, while competing for the same resource, it was developed a new algorithm to aid in a better inventory management of spare parts used only in corrective maintenance (whose failures are unpredictable and random), by analyzing the cost-benefit ratio, which compares the level of service versus cost of each item. The model was tested in a company of urban passenger transport by bus from the city of Natal, who anonymously provided their real data to application in this work

Desenvolvimento de um núcleo versátil e integrado de ferramentas CAD/CAE para a modelagem e simulação de peças mecânicas

Currently there is still a high demand for quality control in manufacturing processes of mechanical parts. This keeps alive the need for the inspection activity of final products ranging from dimensional analysis to chemical composition of products. Usually this task may be done through various nondestructive and destructive methods that ensure the integrity of the parts. The result generated by these modern inspection tools ends up not being able to geometrically define the real damage and, therefore, cannot be properly displayed on a computing environment screen. Virtual 3D visualization may help identify damage that would hardly be detected by any other methods. One may find some commercial softwares that seek to address the stages of a design and simulation of mechanical parts in order to predict possible damages trying to diminish potential undesirable events. However, the challenge of developing softwares capable of integrating the various design activities, product inspection, results of non-destructive testing as well as the simulation of damage still needs the attention of researchers. This was the motivation to conduct a methodological study for implementation of a versatile CAD/CAE computer kernel capable of helping programmers in developing softwares applied to the activities of design and simulation of mechanics parts under stress. In this research it is presented interesting results obtained from the use of the developed kernel showing that it was successfully applied to case studies of design including parts presenting specific geometries, namely: mechanical prostheses, heat exchangers and piping of oil and gas. Finally, the conclusions regarding the experience of merging CAD and CAE theories to develop the kernel, so as to result in a tool adaptable to various applications of the metalworking industry are presented

Estudo da viabilidade técnica do uso das argilas da região do agreste potiguar para produção de peças cerâmicas: caracterização e formulação

In recent decades, ceramic products have become indispensable to the technological development of humanity, occupying important positions in scientific production and consequently in industrial production. One area of the economy that continues to absorb large amounts of the products of this sector is Construction. Among the branches of the ceramic industry, there are the red ceramic industry which is traditionally the basis of that economic sector. Among the reasons for which the red ceramic industry became popular in the country, and specifically in Rio Grande do Norte, is the abundance of this raw material, easily found throughout the national territory. However, it appears that the red ceramic industry has deficiencies in technology and skilled labor, resulting in the production of ceramic goods with low added value. Among the factors that determine the quality of the ceramic products red has the proper formulation of the ceramic mass, the conformation and the firing temperature. Thus, the overall goal of this work is to study the mineralogical and technological properties, two clays from the region of the Wasteland Potiguar industrial ceramist. Therefore, the raw materials were characterized by analysis of Xray diffraction (XRD) analysis, X-ray fluorescence (XRF), particle size analysis (FA), scanning electron microscopy (SEM), optical microscopy (OM ), plasticity index (PI), thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The technological properties of the material were analyzed by water absorption tests (AA%) porosity (% PA), the linear shrinkage (RT%), apparent density (MEA), loss on ignition (PF%) and flexural strength three points (TRF)

Desenvolvimento e teste de um protótipo de reator de plasma com gaiola catódica rotatória para nitretação em lote de pequenas peças

The technique of ion nitriding, despite being fully consolidated in the industry, has great limitations when applied to the treatment of small parts. This is because effects that occur due to non-uniformity of the electric field, generate localized heating in parts, damaging the uniformity of nitrided layer. In addition, because the samples are treated static parts thereof are untreated. To expand the use of plasma nitriding, this work presents the development, assembly and testing of a prototype plasma reactor with rotatory cathodic cage [patent pending], able to meet these needs, giving the material a uniform treatment and opening doors to industrial scale production. The samples tested with hexagonal nuts are 6.0 mm in diameter, made of stainless steel AISI 304 nitrided at a pressure of 1 mbar in an atmosphere of 20% H2 + 80% N2 for 1 h. After treatment, testing visual inspection, optical microscopy and microhardness were carried out to check the effectiveness of the process for uniformity and hardness of the parts. All samples exhibited uniform color, and matte brownish, unlike the untreated samples, silver color and gloss. The hardness of the surface (top and sides) was 65% and even higher than the original hardness. The nitrided layer showed great uniformity in microstructure and thickness. It is concluded, therefore, that the unit was effective constructed for the purposes for which it was designed

Explorando a execução de técnicas estendidas no oboé encontradas em quatro peças contemporâneas

This dissertation presents an investigation of the evolutionary process of extended oboe techniques, through literary analysis and practical research. The objective of this work is to provide assistance to oboists interested in learning these techniques. Additionally, this work encourages the student, through the process of experimentation, to explore the questions that may arise around the aesthetics of sound, the concept of gesture as an additional visual and aural element in music, and the collaboration and “real-time” creation processes. Discussed within the work, are the relationship between the instrument (the oboe) and extended techniques, and two possible definitions of extended techniques, provided by Luk Vaes (2009) and Gardner Read (1993). Also explored are the how and why some composers have utilized extended techniques in their compositions, including brief discussions relating to extended techniques in real-time composition (improvisation), extended techniques and technological resources, theatrical gesture as an extended technique, and suggestions of how musicians might approach theatrical gestures in performance. Four works were visited: “I Know This Room So Well” – Lisa Bielawa (2007-9); “Four Pieces for Oboe and Piano” – Ernst Krenek (1966); “In Freundschaft” – Karlheinz Stockhausen (1978); “Atem” – Mauricio Kagel (1969-70); and an exploration of the difficulties and solutions associated with each extended technique found within these pieces, was carried out. The following founding works on extended oboe techniques were used, as a basis for research: books - Heinz Holliger’s Pro Musica Nova (1972); Gardner Read’s Compendium of Modern Instrumental Techniques (1993); Peter Veale & Claus-Steffen Mahnkopf’s The Techniques of Oboe Playing (1994); and Libby Van Cleve’s Oboe Unbound: Contemporary Techniques (2004); and articles - Nora Post’s “Monophonic sound resources for the oboe: Part I – Timbre” (1984), “Part II- Pitch and other techniques” (1984), and “Multiphonics for the oboe” (1982).

A escrita de Roberto Victorio nas peças Aztlan e Chronos III para violoncelo solo

The cello has a prominent place in the music of Roberto Victorio, due to the fact the composer is a cellist and knows the idiomatic and technical aspects of the instrument. This article analyzes the skills and knowledge necessary to the performance of the works Aztlan and Chronos III for solo cello. As methodological procedure the work was built in three stages: at first a study on notation in the works of Victorio was develeped and how the concepts of desperception, timbre, time and space influence his writing. In a second moment the author made an interview with the composer and finally held performances and recordings of works using the concepts researched in the first two steps.

Sugestões performáticas do bilhete de um jogral para viola sozinha e das três peças para viola e piano de César Guerra-Peixe

This work is aimed at providing an interpretive study of the work for viola and piano titled Three Pieces, and work for solo viola titled Ticket of a Jogral, by Brazilian composer César Guerra Peixe. This study will be divided into three parts: The first will bring a brief history of the composer focusing on his visit to Pernambuco in the late 1940s and early 1950s; the second shows the use of Pernambuco musical regionalism elements used by the composer in the aforementioned documents; the third will present a set of interpretive suggestions based: the analysis of regional musical elements identified in these works; the technical rudiments used in writing for viola depicting the arcades, dynamics, fingerings, articulations, phrasing; and the experiences lived by the author of this research as an interpreter of these works.

Sugestões performáticas do bilhete de um jogral para viola sozinha e das três peças para viola e piano de César Guerra-Peixe

This work is aimed at providing an interpretive study of the work for viola and piano titled Three Pieces, and work for solo viola titled Ticket of a Jogral, by Brazilian composer César Guerra Peixe. This study will be divided into three parts: The first will bring a brief history of the composer focusing on his visit to Pernambuco in the late 1940s and early 1950s; the second shows the use of Pernambuco musical regionalism elements used by the composer in the aforementioned documents; the third will present a set of interpretive suggestions based: the analysis of regional musical elements identified in these works; the technical rudiments used in writing for viola depicting the arcades, dynamics, fingerings, articulations, phrasing; and the experiences lived by the author of this research as an interpreter of these works.