Over the years, industrial partners experienced issues related to inconsistent free ferrite in gray cast iron. In the course of a hot summer and a cold winter, machinability balance varies up to 350%. During warm months it is better and cold months worse. The inconsistent machinability increases the scrap rates by up to 400% and reduces tool life by up to 70%. The ultimate objective of this research is to collaborate with an automotive industrial partner to investigate the periodic machinability variability of gray cast iron engine sleeves, with a goal to reduce the cost and scrap rate of tool inserts. In this study, a significant amount of work was conducted concerning sample preparation for a metallography check. Samples from different months with varying amount of “free ferrite” were collected to study the seasonal effect on their machinability and high-speed machining under similar industrial conditions. Furthermore, a room temperature age strengthening of gray cast iron was conducted to demonstrate how the hardness increase from aging could improve the machinability of gray cast iron. A CBN insert is the second hardest cutting tool after the diamond insert, and is widely used in industry for machining cast iron. It has a high cutting speed is commonly used due to its high hardness and impressive wear resistance. It is known that gray cast iron can naturally age at room temperature or artificially age under a controlled temperature. Under different aging temperatures and times, gray cast iron exhibits a greater hardness after age strengthening, which affects the CBN tool life. The latter is usually limited by flank wear length, however the content of free ferrite in gray cast iron can generate ferrous built-up on the CBN cutting edge and significantly shorten the tool life of the CBN cutting tool. / Thesis / Master of Applied Science (MASc)

No description available.

The goal of this line of research is to add to the existing body of literature on the effect of heat treatments on the microstructure of chrome-bearing white irons and add bend test data to the literature concerning chrome-bearing white irons. This project was intended to support an existing line of research into cast metal-ceramic lattices using chrome white iron as a substitute for sintered ceramic tiles used to defeat projectiles. Chrome-bearing white irons have a substantial quantity of chromium carbides, giving them high hardness and abrasion resistance. Additionally, tiles cast from white iron proved to be more durable than sintered ceramic tiles, breaking into large chunks rather than a powder following an impact. These properties make tiles cast from chrome-bearing white iron a low-cost alternative to sintered carbides. The alloy investigated contained nominally 14 chromium and 3.2 carbon by weight percent. Three-point bend test specimens were cut from cast plates. These specimens were austenitized, air cooled, then tempered prior to three-point bend and hardness testing. The microstructure of the specimens was evaluated using optical microscopy, SEM, and XRD. This line of research revealed that lower austenitization temperatures resulted in a martensitic matrix with fewer, smaller secondary carbides, resulting in higher strength and hardness. In contrast, higher austenitization temperatures produced an austenitic matrix with coarser carbides, resulting in lower strength and hardness. This research did not reveal an appreciable change in ductility over heat treatment temperature. / Master of Science / This research investigates a hard iron alloy capable of replacing expensive ceramics in situations where the goal is to prevent penetration by a projectile. This iron alloy, known as white cast iron, can be cast using typical foundry practices, making it cost-effective. Additionally, the properties can be changed by heat-treatment, a process that involves heating the material to a given temperature, holding it at that temperature for a given amount of time, then cooling the material at a given rate. The results of this research add to the existing understanding of how heat treatment affects the properties of white cast iron. Additionally, this research generated new data about the strength of white cast irons in a three-point bending test, a test not normally used for white cast irons. The research found that high heat-treatment temperatures resulted in a softer white cast iron with lower strength. The structure of the white cast iron treated at these temperatures was predominantly austenite, a soft iron phase, and large carbides, a hard but brittle phase. Temperatures close to the lower end of the temperature range tested resulted in a harder white cast iron with higher strength. The structure of the iron in these conditions contained martensite, a hard iron phase, some austenite, and smaller but more angular carbides.

The rare earth metals cerium, mischmetal, lanthanum, and didymitun were added to irons in the amounts of 0.08 to 0.20 per cent. Silicon and graphite were added to the iron at the electric furnace to change the carbon equivalent of the base metal. The base metal was super-heated to temperatures of 2740º to 2780°F. The molten metal was poured onto the rare earth with a one per cent silicon addition for inoculation. It was then poured into the tensile molds in a temperature range of 2490° to 2540°F. The appearance of the tensile fracture indicated the presence of carbon flotation. The chemical analysis and micro-structure. examination verified this. All of the tensile specimens with carbon equivalent above the eutectic had flotation. As the carbon equivalent increased the carbon flotation increased. The graphite structure in the carbon flotation region was deteriorated from the nodular, and the graphite was nodular in form in the lower portions of the specimens. Cementite was scattered throughout the matrix of all samples except those. with silicon contents above 2.70 per cent. The metal with didymium additions had the most consistent physical properties, while lanthanum produced the lowest physical properties. The tensile and yield values were comparable to those reported in the literature for similar additions. However, the elongation values were low due to the carbon flotation. / Master of Science

This thesis is an investigation on how in architecture structure and material modulate the perception of light. This idea was implemented in the design of a catholic church for the parish of Blacksburg,Virginia. The vision of the church as a community in constant interaction resulted in the design of a complex, in which the chapel is accompanied by a pre-school and a third building containing facilities for the administration of the parish and the residence for the priest. The plaza on which all the buildings have been arranged allows the opportunity for outdoor activities, as well as the contemplation of the beautiful ever-changing views of the mountains that surround the church. The difference in the nature of the activities that take place in each one of the buildings has been expressed through the way structure and materials interact with the natural light producing a distinctive interior quality. / Master of Architecture

O objetivo deste estudo foi comparar, in vitro, a resistência à compressão de 30 raízes bovinas, tratadas endodonticamente, divididas em 3 grupos com 10 raízes cada e restauradas com pino metálico fundido (Grupo 1), pino pré-fabricado de fibra de vidro (Grupo 2) e pino anatômico (Grupo 3). Todas as raízes, com comprimentos de 15mm, foram preparadas internamente para que a espessura dentinária cervical ficasse com 1,5mm, com o objetivo de aumentar a largura do canal radicular. O espaço para o pino foi preparado com 10mm de comprimento. O diâmetro do pino de fibra de vidro escolhido foi o número 2, do sistema utilizado, para que houvesse um espaço entre ele e a estrutura radicular. O Grupo 1 recebeu pino e núcleo metálico fundido cimentado com cimento de fosfato de zinco. O Grupo 2 recebeu pino préfabricado de fibra de vidro cimentado com cimento resinoso Panavia F e núcleo de resina composta Z100. O Grupo 3 recebeu um pino de fibra de vidro modelado no interior do canal com resina composta Z100, cimentado com cimento resinoso Panavia F e núcleo de resina composta Z100. Em todas as raízes dos grupos, um coping metálico foi cimentado com cimento de fosfato de zinco. As raízes foram incluídas em resina acrílica quimicamente ativada, previamente inserida no interior de tubos de PVC e submetidas a testes de compressão em máquina de ensaio Kratos, modelo k2000MP. A carga de compressão foi aplicada a um ângulo de 135 graus ao longo eixo do dente, na face palatina, até que ocorresse uma trinca ou and analysed. The results revealed a statistical difference among groups. Group 1 presented a stronger resistance to fracture than the other groups, which did not present statistical difference. The roots restored with post and cast metallic core were the only ones that presented radicular fracture in the apical root third. The roots that were restored with fibre glass posts presented similar fractures, from the cervical root third to the middle root third. / The aim of this study was to compare, in vitro, the resistance to compression strength of 30bovine roots among canines and incisors endodontically treated, divided into 3 groups with 10 roots each and restored with cast metallic post (Group 1), prefabricated fibre glass post (Group 2), and anatomical post (Group 3). All the roots, with a length of 15mm, were internally prepared so as to their cervical dentin wall thickness would be of 1,5mm, in order to enhance the width of the radicular canal. The space for the post was prepared with 10mm. The diameter of the glass fibre post chosen was the number 2, of the adopted system, so as to create a space between the glass fibre post and the radicular structure. Group 1 received post and cast metallic core cemented with zinc phosphate cement. Group 2 received prefabricated fibre glass post cemented with resin cement Panavia F and composite resin core Z100. Group 3 received a fibre glass post modeled inside the canal with composite resin Z100, cemented with resin cement Panavia F and composite resin core Z100. In all groups, all the roots were cemented with a metallic coping with zinc phosphate cement. The roots were mounted inside pvc pipes with chemically activated acrylic resin, and submitted to compression tests in a universal testing machine Kratos, model k2000MP. The compressive load was done in an angle of 135o in relation to the long axes of the roots, until the occurrence of failure or fracture. The amount of load correspondent to the occurrence of failure or fracture was statistically registered and analysed. The results revealed a statistical difference among groups. Group 1 presented a stronger resistance to fracture than the other groups, which did not present statistical difference. The roots restored with post and cast metallic core were the only ones that presented radicular fracture in the apical root third. The roots that were restored with fibre glass posts presented similar fractures, from the cervical root third to the middle root third.

Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2019-03-21T18:49:10Z No. of bitstreams: 1 Wanessa_Scheidt_2018.pdf: 2637303 bytes, checksum: fd114adf03634dc5d338b2141788ea64 (MD5) / Made available in DSpace on 2019-03-21T18:49:10Z (GMT). No. of bitstreams: 1 Wanessa_Scheidt_2018.pdf: 2637303 bytes, checksum: fd114adf03634dc5d338b2141788ea64 (MD5) Previous issue date: 2018-10-24 / The search for new materials with physicochemical properties for use in devices and sensors are reasons for the study of metal phthalocyanines. Phthalocyanines are highly conjugated macrocyclic compounds of blue or green color and high thermal and chemical stability. They are very used in the formation of fine films well ordered by the casting method. Generally, phthalocyanines exhibit ptype semiconductor properties, but substitutions in their peripheral rings may alter this n-type semiconductivity. Fluorinated phthalocyanines have presented films with good molecular organization, attracting attention to study in solar cells. This work deals with the formation of thin films, using the casting technique, of zinc hexadecafluorophthalocyanines (F16ZnPc) and cadmium (F16CdPc), and the investigation of crystallinity in these films. The objectives of the work were: to analyze the solubility of the compounds the solubility of the compounds in volatile organic solvents; prepare thin films on glass substrates coated with fluorine-doped tin oxide (FTO) and characterize them before and after the heating. Absorption spectroscopy in the ultraviolet-visible (UV-Vis.) region, for solutions of these compounds, have shown that the solvent may influence the observation of the monomeric or dimeric forms. The films show spectra with wider bands and formation of type J aggregates. Changes observed after the heat treatment, carried out at 300 oC for 3 h, suggest the reordering of the molecules on the substrates. Atomic force microscopy (AFM) images showed that there was an elongated preferential arrangement in F16CdPc films and some loss of material for F16ZnPc. Scanning electron microscopy (SEM) crystallites were observed for F16CdPc, but few changes have been observed for F16ZnPc. X-ray diffraction (XRD) results revealed crystalline films, where rings could have different orientations on the substrate. However, after heating, they may have adopted a single orientation, called face on, where the molecules would be in a horizontal position in relation to the substrate. / A busca por novos materiais com propriedades físico-químicas para uso em dispositivos e sensores são motivos para o estudo de ftalocianinas metálicas. As ftalocianinas são compostos macrocíclicos altamente conjugados de coloração azul ou verde e alta estabilidade térmica e química. São muito utilizadas na formação de filmes finos bem ordenados pelo método casting. Geralmente, as ftalocianinas apresentam propriedades semicondutoras do tipo-p, porém substituições em seus anéis periféricos podem alterar essa semicondutividade para tipo-n. Ftalocianinas fluoradas têm apresentado filmes com boa organização molecular, atraindo atenção para estudo em células solares. Este trabalho aborda a formação de filmes finos, usando a técnica casting, das hexadecafluoroftalocianinas de zinco (F16ZnPc) e cádmio (F16CdPc), e a investigação da cristalinidade nesses filmes. Os objetivos do trabalho foram analisar a solubilidade dos compostos em solventes orgânicos voláteis, preparar filmes finos sobre substratos de vidro recoberto com óxido de estanho dopado com flúor (FTO) e caracterizar os mesmos antes e após aquecimento. Espectroscopia de absorção na região do ultravioleta-visível (UV-Vis.), para soluções desses compostos, mostraram que o solvente pode influenciar na observação das formas monomérica ou dimérica. Os filmes apresentam espectros com bandas mais alargadas e formação de agregados tipo J. Alterações observadas após o tratamento térmico, realizado a 300 oC por 3 h, sugerem reordenamento das moléculas sobre os substratos. As imagens de microscopia de força atômica (AFM) mostraram que houve uma organização preferencial alongada em filmes da F16CdPc e alguma perda de material para a F16ZnPc. Nas imagens de microscopia eletrônica de varredura (MEV) foram observados cristalitos para a F16CdPc, porém poucas alterações foram observadas para a F16ZnPc. Resultados de difração de raio X (DRX) revelaram filmes cristalinos, onde anéis apresentariam diferentes orientações sobre o substrato, podendo ter passado para uma única orientação após aquecimento, denominada face on, onde as moléculas estariam em posição horizontal em relação ao substrato.

Bridges, railways stations, warehouses, bandstands, fountains, shop fronts, lamps, gates and other cast-iron elements can still be found throughout Argentina. Some of these elements are impressive, others humble; some are abandoned, others are still in use. Many are part of important monuments; others are so incorporated into the urban landscape that they almost go unnoticed. When one's attention is drawn to these features, however, a company nameplate and place of origin - 'London', 'Liverpool', 'Glasgow' - is usually visible. These elements are so far from Argentina that their appearance begs several questions: why are most of the visible nameplates British? Are they the same as those found in London, Liverpool and Glasgow, or in former British colonies like India, South Africa or Australia? If so, why? Can we think of these elements as British imperial architecture in Argentina? In what context can their arrival in Argentina be understood? Who commissioned and designed them? Are there more Scottish nameplates than English, or any other? Does it matter? Did these elements act as models that were later copied or imitated by local manufacturers? Did they affect architecture and urban development in Argentina? If architecture reflects the view of a society, what do these elements reflect? Considering the wider context of British cast iron manufacturing, this dissertation asks what role Scotland's burgeoning cast iron industry played in the export of British iron products to Argentina during the late nineteenth and early twentieth centuries. If in recent years historians have reconsidered the specific contributions of Scotland and its people to the growth and expansion of Great Britain as an imperial power, this dissertation takes this analysis into the realm of cast iron as an export industry. If British cast iron was ubiquitous throughout the developed world during this period, how do we begin to understand the Scottish cast iron industry as a major contributor to this trade? Here Argentina is used as a micro-study in an attempt to measure and understand that contribution. In addressing some of the above questions, the dissertation attempts to form a coherent analysis of the architectural, historic, cultural and economic dimensions of the phenomenon of Scottish architectural ironwork in Argentina. In so doing, the study hopes to shed light on larger questions concerning British 'informal' imperialism, considering exports of cast iron as a significant component in Britain's attempts at economic leverage and coercion in Argentina during that country's most dramatic period of development and urbanisation. The dissertation arrives at the conclusion that British cast-iron elements found in Argentina are the same or similar to elements found in Great Britain and its colonial empire because they arrived in Argentina through a process of commercial expansion that involved imperial trade routes, global networks, cooperation between British architects and engineers, as well as migration and the assistance of the pro-British elite in Argentina. It is argued that British iron in general, and Scottish in particular, contributed to the expansion of British power and influence in the region through helping shape the architectural and urban environments of Argentina. To reach this conclusion, the thesis is structured in three sections dealing with the three most significant aspects of the thesis: informal empire in Argentina, the iron trade, and Scottish cast-iron architecture in Argentina.

Bobbin Friction Stir Welding (BFSW) is a new application of Friction Stir Welding (FSW) that can be used to join materials together with little to no axial forces. This eliminates the need of a backplate or anvil needed to apply counter pressure against the tool. The applications of BFSW are growing every day. This new technology is helping the automotive industry and many other industries join materials more effectively and efficiently. This technology can be used to join materials with high strength to weight ratios to make cars lighter to increase fuel efficiency. This will also greatly reduce the cost of current joining technologies.The purpose of this research is to prove the feasibility of augmenting a BFSW tool with cutters to join enclosed castings while simultaneously removing ribs and variations in thickness by (1) penetrating a BFSW tool into the material away from an edge; (2) removing any inconsistencies in the material thickness while maintaining a weld; and (3) removing a BFSW tool from the casting away from an edge leaving a clean exit hole without destroying either the casting or the tool.

Thesis (M.S.)--Oregon State University, 2002. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.