Dissertations / Theses: 'Casting powder'

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Pereira, M. F. V. T., M. Williams, and Preez W. B. Du. "Characterization of metal powder based rapid prototyping components with respect to aluminium high pressure die casting process conditions." Journal for New Generation Sciences, Vol 8, Issue 2: Central University of Technology, Free State, Bloemfontein, 2010. http://hdl.handle.net/11462/563.

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Published Article
This paper is based on tests performed on die component specimens manufactured by EOS-DMLS (direct metal laser sintering) and LENS (laser engineered net shape) RP (rapid prototyping) technology platforms, as well as manufactured specimens machined out of preferred standard hot work steel DIN 1.2344. These specimens resemble typical components used in metal high pressure die casting tool sets. The specimens were subjected to a programme of cyclic immersion in molten aluminium alloy and cooling in water-based die release medium. The heat checking and soldering phenomena were analyzed through periodic inspections, monitoring crack formation and evidence of surface washout. At the end of the thermal tests, mechanical strength and hardness tests were performed to assess toughness and core resistance variations in relation to the initial conditions. Finally metallographic investigations were performed through optical microscopy on all the specimens considered. The outcomes of this research will be presented and used by the CSIR for further development and application of the assessed EOS-DMLS and LENS rapid prototyping technologies in rapid die manufacturing techniques and die design principles, including time and economic feasibility criteria to be applied when considering rapid die manufacture.

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Pinheiro, Carlos A. M. "Mould thermal response, billet surface quality and mould-flux behaviour in the continuous casting of steel billets with powder lubrification." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq27226.pdf.

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Ragnarsson, Lars. "Formation of non-metallic inclusions and the possibility of their removal during ingot casting." Doctoral thesis, KTH, Mikro-modellering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12458.

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The present study was carried out to investigate the formation and evolution of non-metallic inclusions during ingot casting. Emphasize have been on understanding the types of inclusions formed and developed through the casting process and on the development of already existing inclusions carried over from the ladle during casting. Industrial experiments carried on at Uddeholm Tooling together with laboratory work and Computational Fluid Dynamics (CFD) simulations. Ingots of 5.8 tons have been sampled and the types of inclusions together with their distribution within the ingot have been characterized. Two new types of inclusions have been found. Type C1 is found originated from casting powder and in the size from a few μm to 30 μm. Type C2 is of macro inclusion type sizing up to 70 μm. The presence of C2 inclusions are few but very detrimental for the quality of the steel. Both types, C1 and C2 consist of alumina, indicating that reoxidation is the main reason for their existence. The protecting argon shroud has been studied by the use of a 1:1 scaled 2D model. Both flow pattern and oxygen measurement have been carried out. CFD has also been used as an auxiliary tool. It has been found that the oxygen pickup through argon gas shroud depends mostly on the distance between the ladle and the collar placed on top of runner. Further increase of gas flow rate above 2.5 m3.h-1 had very little effect on the oxygen distribution since both the flushing effect and the entraining effect with respect to oxygen are enhanced by further increase of inert gas flow rate. In the case of dual gas inlet, the flow in the shroud was found much less diffused compared with either vertical or horizontal injection system. The oxygen content in this arrangement was also greatly reduced. Studies of the runner after casting revealed a sparse non-metallic network structure around the periphery of the steel rod remained in the runner. The surface of the refractory had been severely attacked by the mechanical force from the streaming steel. The erosions of the centre stone and the end stone were on the other hand negligible. CFD calculations showed that the flow at those locations is almost stagnant. The surface of the refractory in contact with the steel was found to have an increased content of alumina. The source for the alumina could come from either exchange reaction of dissolved aluminium replaces the silica or reoxidation products origin from oxygen pick up during the transfer from the ladle to the vertical runner. Inclusions were also found entrapped in the steel refractory interface. It was also found that a formation of a liquid slag film as early as possible during casting would increase the possibility to remove inclusions and especially inclusions generated by the casting powder.
QC 20100617

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Pereira, Manuel Filipe Viana Teotonio. "ADDITIVE MANUFACTURING OF COMPONENTS FOR IN-DIE CAVITY USE, SUITABLE TO WITHSTAND ALUMINIUM HIGH PRESSURE DIE CASTING (HPDC) PROCESS CONDITIONS." Thesis, Bloemfontein: Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/243.

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Thesis (M. Tech. (Engineering: Mechanical)) -- Central University of Technology, Free State, 2013
This research examines the suitability of Additive Manufacturing (AM) for manufacturing dies used in aluminium high pressure die casting. The study was guided by the following objectives: • The reviews of applicable literature sources that outline technical and application aspects of AM in plastic injection moulds and the possibilities of applying it to high pressure casting die. • To introduce AM grown die components in die manufacture. Further, to develop a methodology that will allow industry to apply AM technology to die manufacture. • Revolutionise the way die manufacture is done. The potential for AM technologies is to deliver faster die manufacture turnaround time by requiring a drastically reduced amount of high level machining accuracy. It also reduces the number of complex mechanical material removal operations. Fewer critical steps required by suitable AM technology platforms able to grow fully dense metal components on die casting tools able to produce production runs. • Furthermore, promising competitive advantages are anticipated on savings to be attained on the casting processing side. AM technology allows incorporation of features in a die cavity not possible to machine with current machining approaches and technology. One such example is conformal cooling or heating of die cavities. This approach was successfully used in plastic injection mould cavities resulting in savings on both the part quality as well as the reduction on cycle time required to produce it (LaserCUSING®, 2007). AM technology has evolved to a point where as a medium for fast creation of an object, it has surpassed traditional manufacturing processes allowing for rapidly bridging the gap between ideas to part in hand. The suitability of the AM approach in accelerating the die manufacturing process sometime in the near future cannot be dismissed or ignored. The research showed that there is promise for application of the technology in the not too distant future. In the South African context, the current number and affordability of suitable AM platforms is one of the main stumbling blocks in effecting more widespread applied research aimed at introduction of the technology to die manufacture.

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Attar, H., M. Bönisch, M. Calin, L. C. Zhang, K. Zhuravleva, A. Funk, S. Scudino, C. Yang, and J. Eckert. "Comparative study of microstructures and mechanical properties of in situ Ti–TiB composites produced by selective laser melting, powder metallurgy, and casting technologies." Cambridge University Press, 2014. https://tud.qucosa.de/id/qucosa%3A39023.

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This study presents results of selective laser melting (SLM), powder metallurgy (PM), and casting technologies applied for producing Ti–TiB composites from Ti–TiB₂ powder. Diffraction patterns and microstructural investigations reveal that chemical reaction occurred between Ti and TiB₂ during all the three processes, leading to the formation of Ti–TiB composites. The ultimate compressive strength of SLM-processed and cast samples are 1421 and 1434 MPa, respectively, whereas the ultimate compressive strengths of PM-processed 25%, 29%, and 36% porous samples are 510, 414, and 310 MPa, respectively. The Young’s moduli of porous composite samples are 70, 45, and 23 GPa for 25%, 29%, and 36% porosity levels, respectively, and are lower than those of SLM-processed (145 GPa) and cast (142 GPa) samples. Fracture analysis of the SLM-processed and cast samples shows shear fracture and microcracks across the samples, whereas failure of porous samples occurs due to porosities and weak bonds among particles.

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Pereira, Márcia Maria da Silva Monteiro. "Desenvolvimento de pó fluxuante sem flúor para o lingotamento contínuo de placas de aço baixo carbono." Universidade de Taubaté, 2015. http://www.bdtd.unitau.br/tedesimplificado/tde_busca/arquivo.php?codArquivo=808.

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Há uma clara tendência na indústria para eliminar o flúor dos pós fluxantes usados durante o lingotamento contínuo de aços, pois, embora o flúor seja importante no comportamento de fusão, infiltração e cristalização do filme de escória, ele evolui facilmente a partir de escórias para substâncias gasosas prejudiciais à saúde, como o ácido fluorídrico. Além disso, os compostos contendo flúor ocasionam problemas de armazenamento, de utilização de resíduos sólidos e contribui para a corrosão dos equipamentos. Com a finalidade de retirar o flúor da formulação desses pós, foi desenvolvida uma formulação isenta de flúor, para a aplicação em aços baixo carbono, utilizando óxido de boro. A fim de comparar o comportamento do produto desenvolvido com o do produto tradicional, foram realizados testes laboratoriais e industriais. Nos testes laboratoriais, o produto isento de flúor apresentou menor velocidade de fusão, temperatura de fusão mais baixa, menor cristalinidade e menor viscosidade que o pó tradicional. Nos ensaios industriais, a absorção de alumina foi maior para o produto sem flúor que também obteve uma redução significativa da corrosão da válvula submersa, porém apresentou um menor consumo de pó. Com a finalidade de corrigir o baixo consumo de pó, realizou-se um ajuste na viscosidade da formulação desenvolvida e um novo ensaio, no qual o consumo de pó foi similar ao do produto tradicional. Dessa forma, conclui-se que a formulação desenvolvida e testada pode ser utilizada em substituição da formulação tradicional.
There is a clear trend in the industry to eliminate fluorine from mould powders used during continuous casting of steel, even fluorine is important in the melting behavior, infiltration and slag film crystallization, it evolves from the slags to gases that are harmful to health, such as hydrofluoric acid. Furthermore, the compounds that contain fluorine can cause storage problems, use of solid residues and contribute to the corrosion of the equipment. In order to remove fluorine from the formulation of these powders, a fluor free formulation has been developed for use in low carbon steels, by using boron oxide. For the purpose of to compare the behavior of the product developed with the traditional products, industrial and laboratory tests were performed. In the lab tests the fluor free material showed lower melting speed, lower melting temperature, lower crystallinity, lower viscosity and higher fluidity than the recipe with fluorine. In the industrial tests, the alumina absorption was higher for recipe without fluorine which also obtained a significant reduction in corrosion of the submerged valve, SEN, but presented a lower powder consumption. In order to correct the low consumption, an adjustment of the viscosity of this recipe was made, and a new industrial test showed that the powder consumption of the recipe without fluorine was similar to the recipe with fluorine. Thus, it demonstrates that the recipe without fluorine can be used in an industrial scale replacing the recipe with fluorine.

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Pereira, Helena Ravache Samy. "Proposta de formulação de argamassas para assentamento e revestimento de paredes e tetos com incorporação de pó de exaustão de fundição." Universidade do Estado de Santa Catarina, 2014. http://tede.udesc.br/handle/handle/613.

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Made available in DSpace on 2016-12-08T15:56:17Z (GMT). No. of bitstreams: 1 resumo tese.pdf: 15008 bytes, checksum: b3fcb8e618165bdab7dabdeefc264a32 (MD5) Previous issue date: 2014-08-18
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The use of casting waste powder from industry in mortars brings environmental benefits by minimizing the impact caused by the disposal of waste on the environment. Casting exhaust powder is a waste product from the regeneration of sand molds from the core making process sector from a foundry industry located in Joinville/SC. This work aims to propose a formulation method for laying mortars, and wall and ceiling coating mortars incorporating casting waste powder whose use would result in a product with adequate technical performance. The fine aggregates, the casting waste powder and mortars were characterized by standard assays, electron microscopy and X-ray powder diffraction. The laying and coating mortar compositions were based on a system of equations obtained using the mixture design methodology. Through this study, results of experimental character and a method for formulating mortars that can be useful in the construction sector were obtained, thus contributing to a better understanding of the use of casting waste in mortars.
O uso de resíduos de fundição como o pó de exaustão em argamassas traz benefícios ambientais através da minimização do impacto causado pelo descarte do resíduo no meio ambiente. O pó de exaustão de fundição é um resíduo proveniente da regeneração dos moldes de areias do setor de macharia de uma indústria de fundição localizada em Joinville/SC. Este trabalho tem por objetivo propor um método de formulação para argamassas de assentamento e revestimento de paredes e tetos com incorporação de pó de exaustão cuja utilização resulte em um produto com desempenho técnico adequado. Os agregados miúdos, o resíduo pó de exaustão de fundição e as argamassas foram caracterizados por ensaios normalizados, microscopia eletrônica e difração de raios-X. As composições das argamassas em massa foram obtidas através de planejamento de experimentos de delineamento por misturas. A proposta de formulação de argamassas de assentamento e revestimento de paredes e tetos foi baseada na resolução de sistemas de equações obtidas através do modelamento estatístico das propriedades. Por meio deste estudo, foram obtidos resultados de caráter experimental e um método de formulação de argamassas que podem ser úteis ao setor de construção civil, contribuindo desta forma com o melhor entendimento do uso de resíduos de fundição em argamassas.

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Yang, Zhengtao. "CHARACTERIZATION AND AQUEOUS COLLOIDAL PROCESSING OF TUNGSTEN NANO-POWDERS." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2693.

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Extensive attention has been paid to consolidate nanoparticles into nanocrystalline components that possess better properties than their coarse-grained counterparts. Nanocrystalline monolithic tungsten (W) has been envisaged to possess better properties than coarse-grained tungsten and to improve the performance of many military components. Commercially available nano-W powders were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and Brunauer, Emmett, and Teller (BET) measurement. While the bulk of nano-W powders consisted of bcc-W as confirmed by XRD and TEM, much of their surface consisted of WO3 with traces of WO2 and WC. Despite the irregular morphology and agglomerates greater than 1 m in size, the diameter of individual nano-W powders ranged from 30 to 100 nm with a surface area of 10.4 m2/g. To obtain green bodies of higher densities and more homogeneous microstructures after consolidation, W nanopowders were de-agglomerated in water and slip cast in plaster molds. De-agglomeration in water was conducted by repeated ultrasonication, washing, centrifuge and pH adjustment. The change in particle size and morphology was examined via SEM. After the initial surface oxide was removed by repeated washing, the reactivity of W nanoparticles to water was somewhat inhibited. Increasing the number of cycles for ultrasonication and washing increased the pH, the degree of de-agglomeration and the stability of W suspension. The zeta potential was more negative with increasing pH and most negative at pH values close to 5. Viscosity also decreased with increasing pH and reached a minimum at a pH 5. To obtain the highest solid loading with the lowest viscosity, the pH value of W suspension was adjusted to 5 using aqueous tetramethylammonium hydroxide solutions. The relative density of the slip cast increased with longer ultrasonic time, increasing slurry pH up to 5, and consequent increase in solids loading. Smaller particles were separated from larger ones by ultrasonication, washing with water and centrifugation. At a 27.8 vol.% solids loading, the size-separated fine W slurry was slip cast into pellets with relative green densities up to 41.3 % and approximate particle sizes of 100 nm. W powders were also ultrasonicated in aqueous poly (ethyleneimine) (PEI) solutions with various concentrations. SEM examinations of particle sizes showed that 1 wt.% PEI led to the optimum dispersion and ultrasonication for longer time with a low power resulted in better dispersion. 0.5 g of W powders were ultrasonicated in 10 ml aqueous poly (allylamine hydrochloride) (PAH) solutions with molar concentrations ranging from 0.01 to 0.05 M. W suspensions with 0.03 M and 0.04 M PAH after two washing cycles showed improved dispersion. Cold isostatic pressing can further increase the green density following slip casting. Sintered slip casts made from de-agglomerated nanoparticle W showed a lower density, more uniform microstructure, smaller grains and smaller pores than the sintered dry pressed pellets.
M.S.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Materials Science & Engr MSMSE

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Stocky, Robin. "Etude du traitement de poudres et influence des caractéristiques obtenues sur la transparence de céramiques du type spinelle." Electronic Thesis or Diss., Valenciennes, Université Polytechnique Hauts-de-France, 2020. http://www.theses.fr/2020UPHF0015.

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Ce travail d’élaboration de céramique transparente pour la protection balistique s’inscrit dansun contexte d’allégement de structure et d’amélioration des propriétés optiques et mécaniques.Le remplacement de la face avant en verre par une céramique polycristalline, telle que lespinelle MgAl2O4 permet d’optimiser considérablement les performances balistiques, touten diminuant la masse et le volume de la protection. Le principal objectif de ce travail a étél’obtention d’une céramique transparente type spinelle avec une microstructure à grains finspermettant d’obtenir de bonnes propriétés mécaniques et balistiques. Afin de contrôler lamicrostructure de la céramique, il est nécessaire d’adopter des conditions de frittage douces,c’est pourquoi l’utilisation d’une poudre très fine et réactive a été envisagée. Mais l’utilisationd’une telle poudre soulève souvent des problèmes de mise en forme et de frittage homogène,qui sont un frein à la transparence de la céramique. Cette étude s’est tout d’abord focaliséesur la poudre de spinelle en comparant quatre poudres de spinelle commerciales. Cette partiea permis de mettre en avant les particularités rhéologiques ou morphologiques nécessaires àla mise en forme des céramiques, influençant ainsi le frittage et donc la transparence finale,comme par exemple le réarrangement granulaire, la surface spécifique ou la perméabilité. Unefois la poudre de spinelle choisie, une étude de traitement a été menée sur cette dernièreen exploitant son agglomération afin d’obtenir une céramique transparente dans le visibleavec une microstructure fine. Le challenge a été d’optimiser sa mise en forme par différentstraitements et son frittage. Cette étude s’est soldée par l’obtention de céramique transparenteà fine microstructure (taille de grain de 4-5_m) et avec une transmission en ligne de 71%à 650nm, grâce à l’utilisation d’un spray dryer et d’un additif PEG. Une autre étude s’estconcentrée sur la possibilité de renforcer ce spinelle transparent par l’ajout de matériau dedifférentes natures (nanodiamant, alumine, zircone). L’objectif a été d’améliorer les propriétésmécaniques du spinelle, tout en gardant intactes ses propriétés optiques. L’ajout de phasesecondaire en tant que renfort soulève de nombreuses difficultés de par leurs tailles, l’indicede réfraction différent du spinelle et les éventuelles réactions qui peuvent se produire lors dufrittage. Une dernière étude a été menée sur la mise en forme de forme complexe, permettantainsi d’autres applications du spinelle en tant que protection. La voie classique par pressageuniaxial s’étant avéré peu concluante, une mise en forme par voie liquide s’est montrée êtreune solution envisageable. Elle a nécessité une étude complète de la mise en suspension duspinelle et son comportement lors de sa mise en forme. Chacune des études s’est appuyée surla morphologie de la poudre et son évolution lors de la mise en forme et le frittage, par lebiais d’études microstructurales et rhéologiques ainsi que l’évaluation des propriétés optiqueset mécaniques
This work aims to elaborate the benefits of transparent ceramics in ballistic protection systemswhich are employed by the military in their vehicles. The main focus lies on improving bothoptical and mechanical properties as well as reducing the weight of the system as a whole.Substituting the standard multilayered front glass panel with a polycrystalline ceramic, suchas the spinel MgAl2O4 used in this work, considerably improves its ballistic performance, whilesimultaneously reducing its mass and volume. In order to achieve these improved properties,which most commonly result from a fine-grained microstructure, a very fine grained andreactive powder is used. However, the use of such powders raises additional difficulties inshaping and homogeneous sintering, all of which have a negative effect on the transparency ofthe ceramic. The first focus of this study is the selection of an appropriate powder, carried outby comparison of multiple commercially available powders. This following step highlightedthe rheological and morphological particularities of the examined powders, necessary for theshaping of ceramics, and influencing the sintering and thus the final transparency, such asgranular rearrangement, specific surface area or permeability. Once the spinel powder hadbeen chosen, a processing study was carried out on it, exploiting its agglomeration to obtain avisibility transparent ceramic with a fine microstructure. Since some nanopowders presentedwith difficulties in shaping, further optimization of different treatment methods (use of afreeze dryer, an oven or a spray dryer) in combination with appropriate sintering approacheswere explored. Ultimately, by combining a spray dryer and a PEG additive, the study resultedin the production of a transparent spinel ceramic with a fine microstructure (grain size of4-5 µm) and an in-line transmission of 71% at 650 nm. A parallel study on strengtheningthe transparent spinel by introducing various additives, such as nanodiamond, alumina, andzirconia was also carried out. The primary objective was to improve the mechanical propertiesof the spinel, while keeping its optical properties untouched. The addition of a secondaryphase as reinforcement raised many difficulties, mainly due to the size disparity, differentrefractive index of the spinel and potential unwanted reactions that can occur during sintering.Lastly, the final study focused on complex shaping of spinel ceramics for ballistic protection.As a prerequisite, a complete examination of the spinel’s suspension and its behaviour duringshaping had to be performed. The new findings validated liquid shaping as a viable solutionto achieve transparent 3D profiles, while the classic uniaxial pressing route did not yield anyconclusive results. Each of the studies was based on the morphology of the powder and itsevolution during shaping and sintering. The results were obtained through microstructuraland rheological studies as well as the evaluation of optical and mechanical properties

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Ferguson, Lucian Garret. "Spectrally selective, matched emitters for thermophotovoltaic energy conversion fabricated by tape casting process /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/10589.

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Elahipanah, Zhaleh. "Thermo-Physical Properties of Mould Flux Slags for Continuous Casting of Steel." Thesis, KTH, Materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101270.

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Due to the high efficiency and productivity of continuous casting process, this method has been the most employed process to produce steel in past decades. The need to improve and optimize the finished product made it essential to gain more knowledge about the process, types of defects that may occur and the reasons for them. Moreover, the solutions for reducing the shortcomings in continuous casting process have been an intriguing subject to study. Many attempts have been done in order to reach this goal. Understanding, determining and optimizing the mould flux slag properties is especially important, since it plays an important and significant role in this process. For this, it is of outmost importance to acquire more knowledge about different properties of mould flux powders. Hence, there has been a world wide effort to measure and model the properties of mould flux properties, such as liquidus and solidus temperatures, heat capacity, enthalpy, thermal expansion, density, viscosity, electrical conductivity, surface tension and thermal conductivity. This thesis presents a brief review on continuous casting process, mould flux powder and its properties and characteristics. Furthermore, it focuses on the thermo-physical properties of mould fluxes. In present work, different industrial mould flux powders have been analyzed to measure their viscosity, break temperature, physical properties such as density, flowablity of powder, slag structure and chemical composition. The experimental data have been compared to some of the most commonly used models such as Riboud model, Urbain model, Iida model and KTH model.

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Johnson, Phillip M. "Casting Off the Shadow: Tactical Air Command from Air Force Independence to the Vietnam War." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1398949297.

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Kästel, Matilda. "Åtråvärda objekt : En gestaltning av troféns materialitet." Thesis, Konstfack, Keramik & Glas, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-4136.

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This thesis revolves around my work Desirable Objects, an installation in glass and other materials, which deals with objectification based on female and animal trophies. The topics included are those that have been crucial to my working process; craft, post-colonial studies and European hierarchical dualism, where woman and nature are seen as connected, but inferior. My motivation has been to get a better understanding of underlying power structures, and put this knowledge in relation to my own work. This process has led me to make a full body casting of my own body as a method of self-exploitation, in an attempt to expose myself to a similar power perspective. By making the dualistic connection between woman and nature, I am commenting a phenomenon that in my view has resulted in a similar exploitation of both.
Åtråvärda objekt

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Silva, Daniel dos Reis. "Análise termodinâmica da formação de Al2O3 durante o lingotamento contínuo através da interação química entre pós fluxantes sem flúor e uma liga de Fe líquido saturada com alumínio e oxigênio." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/26870.

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Pós fluxantes são escórias sintéticas utilizadas no processamento do aço via lingotamento contínuo com o objetivo de promover maior qualidade superficial ao produto lingotado. Para tanto, os pós fluxantes desempenham as seguintes funções: (i) promoção do isolamento térmico e químico do aço, (ii) absorção das inclusões nãometálicas provenientes do aço, (iii) promoção da lubrificação do molde e (iv) controle da transferência de calor entre o aço e o molde. O bom desempenho de cada função está diretamente relacionado às propriedades físicas e químicas que os pós apresentam, as quais são funções de sua composição química. Durante o processo de lingotamento, os pós fluxantes sofrem alterações em sua composição original proporcionadas por diferentes mecanismos que afetam as propriedades dos pós fluxantes. Um dos principais mecanismos responsáveis pelas alterações da composição das escórias é a interação química que ocorre entre o aço líquido e o pó fluxante fundido. Nesse trabalho foram realizadas simulações via aplicativo termodinâmico FactSage com o intuito de avaliar as interações entre metal líquido e escória. Três sistemas simples para a escória – um ternário (CaO-Al2O3-SiO2), um quaternário (CaO-Al2O3-SiO2-MgO) e um quinário (CaO-Al2O3-SiO2-MgO-Na2O) – e uma liga de Fe saturada em alumínio e oxigênio – 0,1%, 0,01% e 0,001% de Al – foram escolhidos para a realização das simulações, visando avaliar o incremento de Al2O3 da escória através da interação entre o alumínio dissolvido no ferro e a sílica presente na escória. O aumento do teor de alumina na escória foi quantificado para cada um dos três sistemas estudados em função do teor de Al e da razão S/M (kg de pó fluxante/t de metal líquido). Foram realizadas curvas de resfriamento para as escórias – que sofreram alterações em sua composição – para avaliar a influência da variação da composição sobre o comportamento de solidificação destas, baseadas em diagramas pseudobinários. Por fim, foram realizados cálculos de viscosidade para estas escórias através do modelo IRSID, para analisar a influência da composição sobre a viscosidade. Mostrou-se, para as condições escolhidas, que as alterações da composição química das escórias devido às interações entre metal líquido e escória são significativas, afetando as propriedades dos pós fluxantes, tais como seu comportamento de solidificação e sua viscosidade.
Mold powders are synthetic slags used in steel processing via continuous casting in order to promote greater surface quality to casting product. Thus, the mold powders perform the following functions: (i) promotion of the thermal and chemical insulate of steel, (ii) absorption of non-metallic inclusions from the steel, (iii) promotion of the lubrication of the mold and (iv) control of the heat transfer between steel and mold. The good performance of each function is directly related to physical and chemical properties presented by the powders, which are functions of their chemical compositions. During casting process, the mold powders undergo changes in their original composition provided by different mechanisms that affect the properties of mold powders. One of the main mechanisms responsible for changes in the composition of the slag is the chemical interaction that occurs between liquid steel and molten mold powders. In this work, simulations were carried out via thermodynamics software FactSage with the purpose of evaluating the interactions between the liquid metal and slag. Three simple systems – a ternary (CaO-Al2O3-SiO2), a quaternary (CaO-Al2O3- SiO2-MgO) and a quinary (CaO-Al2O3-SiO2-MgO-Na2O) – and a Fe alloy saturated with aluminum and oxygen – 0,1%, 0,01% and 0,001% Al – were chosen to perform the simulations in order to evaluate the increase of Al2O3 in slag through the interaction between the dissolved aluminum in iron and silica present in the slag. The increase of alumina content in the slag was quantified for each of the three systems studied as a function of Al content and the ratio S/M (mold powder kg/t liquid metal). Cooling curves were performed for slags – that suffered changes in their composition – to assess the influence of the composition variation on the behavior of slags, based on the pseudo-binary diagrams. Calculations of viscosity for these slags through the IRSID model to analyze the influence of chemical composition on the viscosity were performed. For the conditions chosen, it was shown that changes in chemical composition of the slag due to interactions between liquid metal and slag are significant, affecting the properties of fluxing powders, such as the solidification behavior and viscosity.

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RIBEIRO, CHRISTIANE. "Obtenção e caracterização de biocerâmicas porosas à base de fosfatos de cálcio processadas com a utilização de albumina." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11660.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP

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Kotriwala, Arzam Muzaffar. "Load Forecasting for Temporary Power Installations : A Machine Learning Approach." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211554.

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Sports events, festivals, construction sites, and film sites are examples of cases where power is required temporarily and often away from the power grid. Temporary Power Installations refer to systems set up for a limited amount of time with power typically generated on-site. Most load forecasting research has centered around settings with a permanent supply of power (such as in residential buildings). On the contrary, this work proposes machine learning approaches to accurately forecast load for Temporary Power Installations. In practice, these systems are typically powered by diesel generators that are over-sized and consequently, operate at low inefficient load levels. In this thesis, a ‘Pre-Event Forecasting’ approach is proposed to address this inefficiency by classifying a new Temporary Power Installation to a cluster of installations with similar load patterns. By doing so, the sizing of generators and power generation planning can be optimized thereby improving system efficiency. Load forecasting for Temporary Power Installations is also useful whilst a Temporary Power Installation is operational. A ‘Real-Time Forecasting’ approach is proposed to use monitored load data streamed to a server to forecast load two hours or more ahead in time. By doing so, practical measures can be taken in real-time to meet unexpected high and low power demands thereby improving system reliability.
Sportevenemang, festivaler, byggarbetsplatser och film platser är exempel på fall där kraften krävs Tillfälligt eller och bort från elnätet. Tillfälliga Kraft Installationer avser system som inrättats för en begränsad tid med Vanligtvis ström genereras på plats. De flesta lastprognoser forskning har kretsat kring inställningar med permanent eller strömförsörjning (zoals i bostadshus). Tvärtom föreslår detta arbete maskininlärning metoder för att noggrant prognos belastning under Tillfälliga anläggningar. I praktiken är thesis Typiskt system drivs med dieselgeneratorer som är överdimensionerad och följaktligen arbetar ineffektivt vid låga belastningsnivåer. I denna avhandling är en ‘Pre-Event Casting’ Föreslagen metod för att ta itu med denna ineffektivitet genom att klassificera ett nytt tillfälligt ström Installation till ett kluster av installationer med liknande lastmönster. Genom att göra så, kan dimensioneringen av generatorer och kraftproduktion planering optimeras därigenom förbättra systemets effektivitet. Load prognoser för Tillfälliga Kraft installationer är ook användbar Medan en tillfällig ström Installationen är i drift. En ‘Prognoser Real-Time’ Föreslagen metod är att använda övervakade lastdata strömmas till en server att förutse belastningen två timmar eller mer i förväg. Genom att göra så, kan praktiska åtgärder vidtas i realtid för att möta oväntade höga och låga effektbehov och därigenom förbättra systemets tillförlitlighet.

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Arbelaez, Natalia. ""Insignificant Grandeur"." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1435530944.

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Pack, Alison Greer. "Some People Call Them Dolls: Capturing the Iconic Power of the Female Form in Non-ferrous Metals." [Johnson City, Tenn. : East Tennessee State University], 2003. http://etd-submit.etsu.edu/etd/theses/available/etd-0330103-135724/unrestricted/PackA040803d.pdf.

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Thesis (M.F.A.)--East Tennessee State University, 2003.
Title from electronic submission form. ETSU ETD database URN: etd-0330103-135724. Includes bibliographical references. Also available via Internet at the UMI web site.

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Lima, Camila Cristina Souza. "Monges hospitaleiros: imagem das monarquias ibéricas nos espaços régios nos Mosteiros da Ordem de São Jerônimo (1495-1598)." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/16/16133/tde-31072018-103547/.

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Em Portugal e Castela, entre fins do século XV e ao longo do século XVI, importantes espaços da monarquia foram ocupados pela Ordem de São Jerônimo. A presente tese ocupa-se de tratar dos incentivos dos monarcas desses dois reinos às casas jerônimas como parte da propaganda régia. Em especial trataremos dos dois monastérios mais favorecidos pelas monarquias: Santa Maria de Belém e San Lorenzo El Real del Escorial. Os dois edifícios foram construídos por iniciativa real, em momentos de alargamento do poderia desses reinos em outros continentes e em contextos em que a possibilidade de união dos reinos peninsulares era vislumbrada, inicialmente por D. Manuel e depois por Felipe II. A pesquisa se ocupou em estudar documentos iconográficos, textuais e de cultura material, em especial, buscando compreender o discurso expresso nos edifícios aliados ao discurso oficial escrito sobre o governo desses monarcas.
In Portugal and Castile, between fifteenth century and sixteenth century, important spaces of the monarchy were occupied by the Order of St. Jerome. The present thesis deals with the incentives of the monarchs of these two kingdoms to monasteries of St. Jerome as part of the royal propaganda. In particular we will treat the two monasteries most favored by the monarchies: Santa Maria de Belém and San Lorenzo El Real del Escorial. These two buildings were built on the initiative of kings, at times of enlargement of the kingdom and in contexts in which the possibility of union of the peninsular kingdoms was glimpsed, initially by D. Manuel and later by Felipe II. The research was focused on studying iconographic, textual and material culture documents, in particular, seeking to understand the discourse expressed in the buildings allied to the official written discourse on the government of these monarchs

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Souza, Júnior Almir Marques de. "Teoria política e poder régio em Castela (1252-1284)." reponame:Repositório Institucional da UFF, 2014. https://appdesenv.uff.br/riuff/handle/1/454.

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O presente trabalho analisa a teoria política desenvolvida durante a Idade Média, mais especificamente no reino de Castela e Leão durante o século XIII. O período abrangido pela análise, dos anos de 1252 a 1284, diz respeito ao reinado do monarca Afonso X, que recebeu o cognome “o Sábio”. Durante o seu governo, ocorre a produção de uma farta bibliografia nas matérias do direito e da história, na qual podemos identificar os principais pressupostos de um discurso político que busca ressaltar a superioridade da autoridade régia em relação aos demais poderes senhoriais existentes naquele contexto. Paralelamente à produção destas obras, temos um franco processo de arrefecimento das relações entre monarquia e aristocracia nobiliárquica no reino. O tensionamento na relação entre essas frações de grupo no poder chegou ao ponto em que os nobres se insurgiram por duas vezes contra o poder do rei. Lutando contra as interpretações reducionistas que afirmam que a elite senhorial dilapidava o poder das monarquias, buscaremos, ao longo da tese, enfatizar que tanto a nobreza como a monarquia eram grupos pertencentes a uma mesma classe social, compartilhando os mesmos valores e referencias de afirmação de classe. Por mais que tenham ocorrido disputas no interior da classe aristocrática, tanto a monarquia quanto a aristocracia não concebiam uma sociedade em que uma não dependesse da outra para subsistir.
The present work analyzes the political theory developed during the Middle Ages, specifically in the kingdom of Castile and Leon during the thirteenth century. The period covered by the analysis, from the years 1252 to 1284, covers the reign of King Alfonso X, who received the epithet “the Wise”. During his government, we have an abundant production of literature in the fields of law and history, in which we can identify the main assumptions of a political discourse that seeks to highlight the superiority of the royal authority in relation to other existing aristocratic powers in that context. Alongside the production of the work, we have an open process of cooling of relations between monarchy and aristocracy nobility in the kingdom. The tension in the relationship between these fractions of the group in power has reached the point where the nobles rebelled twice against the king’s power. Fighting reductionist interpretations that claim that the noble elite dilapidava the power of monarchies, seek, throughout the thesis, emphasize that both the nobility and the monarchy were groups belonging to the same social class, sharing the same values and references to assertation class.For more disputes that have occurred within the aristocratric class, both the monarchy as the aristocracy did not conceive of a society in which one did not depend on another to survive.

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Marquer, Julie. "Propagande politique et Islam d’Occident sous le règne de Pierre Ier de Castille (1350-1369)." Thesis, Paris 4, 2014. http://www.theses.fr/2014PA040154/document.

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S’intéresser à la place de l’Islam dans les propagandes politiques du règne de Pierre Ier de Castille (1350-1369) amène à s’interroger sur les paradoxes et ambiguïtés du rapport à l’Autre. L’Islam désigne ici différents objets ; le terme fait référence à la fois à la puissance politique et militaire des Nasrides et Mérinides, et à un ensemble religieux et culturel. Leur instrumentalisation dans diverses formes de propagande, textuelles et architecturales, a pour but de renforcer le pouvoir de l’initiateur de cette propagande. La mise en lumière des diverses modalités de cette instrumentalisation permettra de questionner et reconsidérer la frontière politique, religieuse et culturelle dans la péninsule ibérique du XIVe siècle. L’exemple du règne de Pierre Ier montre à quel point la frontière avec l’Autre est mouvante et évanescente, et son renforcement ou son amenuisement dépend des intérêts politiques en jeu, des rapports de force, de la motivation des acteurs ou encore de différents types de convergence qui ont rendu possible l’intégration et l’assimilation de formes et de concepts artistiques, politiques et littéraires. En confrontant les types de sources et les points de vue, on pourra mieux saisir, dans son ensemble et sa complexité, le rapport excluant ou incluant que les chrétiens entretiennent avec l’Islam, tant dans leurs pratiques politiques que dans leurs représentations symboliques. En effet, l’Islam est utilisé comme une altérité tantôt positive, tantôt négative, mais il cesse parfois aussi de représenter une forme d’altérité. Ce rapport dialectique renvoie à la problématique de la place qu’occupe l’Islam dans la formation de la culture castillane ainsi que dans la construction de l’État Moderne
Exploring the place of Islam in the political propagandas during the reign of Peter of Castile (1350-1369) leads to questioning the paradoxical and ambiguous aspects of an approach to Otherness. Islam here refers to various items: the political and military power of the Nasrids and the Merinids, as well as a religious and cultural body. The instrumentalization of these items through various forms of propaganda, either textual or architectural, aims at reinforcing the power of their initiator(s). Bringing out the various modalities of this instrumentalization will allow us to question and reconsider the political, religious and cultural frontier in the 14th century Iberian Peninsula. The example of the reign of Peter of Castile shows how shifting and ephemeral the frontier with Otherness can be, and its strengthening or its dwindling depends on the political interests at stake, the balance of power, the motivation of the protagonists as well as the different types of convergence which have allowed the integration and the assimilation of artistic, political and literary patterns and concepts. By confronting the various types of sources and points of view, it will be easier to fully understand, in its entirety and complexity, the either excluding or including relationship that the Christians have with Islam, both in their political practices and in their symbolic representations. Indeed, Islam is utilized as a form of otherness which is sometimes positive, sometimes negative, but it also occasionally ceases being viewed as such. This dialectical connection is closely linked to the part that Islam has played in the formation of Castilian culture as well as in the construction of Modern State

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Gallégo, Josée. "Le mythe des Argonautes dans le théâtre du Siècle d'or espagnol." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCA041.

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Le mythe de la Toison d'or est le récit d'une aventure maritime jusqu'au bout du monde pour y rapporter un emblème de royauté. Chassé par un oncle usurpateur, Jason triomphe des épreuves qui lui sont imposées grâce à l'amour de la magicienne Médée. Tamis des orpailleurs, trésor caché, parchemin sacré, constellation ou Saint-Graal, le bélier volant qui sauva Hellé et Phryxos de la noyade a été l’objet de nombreuses interprétations.En 1430, le duc de Bourgogne, Philippe le Bon, fonde l'ordre de la Toison d'or pour fédérer les princes de la chrétienté. À l'issue de la cérémonie d'intronisation, un collier est remis au nouveau chevalier. Pourtant, l'évêque de Chalon se récrie face au choix de ce héros parjure, et l'on décide de lui adjoindre Gédéon, dont les brebis s'étaient couvertes de rosée mariale, en signe de la victoire prochaine sur les mécréants.Par le jeu des alliances matrimoniales, le titre de Souverain de l'ordre échoit à Charles Quint qui ajoute à ses armoiries le « Plus Oultre ». Lors de la bataille de Lépante, en 1571, la Galera Real Argo proclame, à coups de décorations, fresques, statues et devises, le projet de la monarchie catholique de terrasser le dragon qui s'est emparé des territoires chrétiens, assimilés au mouton doré du mythe.Quand la saga des Argonautes arrive sur les planches du théâtre auriséculaire, elle jouit d'un immense avantage. Le héros est connu dans son aspect le plus lumineux et le traitement bourguignon alimente la résistance face aux hérétiques de toutes sortes.Si le mythe se prête aux innovations les plus spectaculaires et relaie les valeurs de la monarchie, il entretient une singulière relation avec la politique menée par ses princes, tandis que les guerres laissent attendre l'âge d'or tant espéré, que la dette se creuse, que la cour mène un train de vie dispendieux et que la corruption gagne progressivement toute la société.Avec l'Art Nouveau de faire des comédies, Lope de Vega ouvre une brèche qui permet de voir derrière les ors et les fastes de la cour la lente désagrégation de la monarchie
The story of Jason is a most ancient myth and survives in various forms. A more widespread interpretation relates the myth of the fleece to a method of washing gold from streams. More often, the Golden Fleece represents royal power, the spring-hero or a book on alchemy. According to Apollonius of Rhodes, a flying golden ram rescued Phrixus and Helle as their stepmother wantedto kill them. Phrixus safely reached Colchis where he sacrificed the ram and gave its skin to Aetes. Meanwhile, Pelias had usurped the throne of Eson and as his son reclaimed it, sent him to fetch the Golden Fleece. Jason assembled a remarkable group of heroes on board the Argo. At Colchis, the witch Medea helped Jason to complete the mortal tasks. Upon returning, she plotted the death of Jason's uncle, so both took refuge with their children in Corinth. There, the hero betrayed her as he fell in love with Creusa. The witch got rid of this rival, burnt the palace and slaughtered their chidren.In 1430, the Duke of Burgundy founded the Order of the Golden Fleece. As a shield, a sheepskin was suspended from a jeweled collar of firesteel linked by flints. But the choice of Jason caused controversy, so Bishop of Chalon linked it to the fleece of Gideon. As part of the Burgundian inheritance, the Order was a welcomed instrument to the ambitious Habsburgs to strengthen the bonds and Charles V added as a motto « Plus Oultre ».Performances of the Spanish Golden Age Theater were used to develop the ideology of the Catholic Monarchy. When Lope de Vega published el “Arte nuevo”, he introduced the tradition of the « Mirror for Prince » giving opportunity to express one's point of view, despite the censure

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Chi-HeChen and 陳麒合. "Using gel casting to produce FeSiCr alloy powder molding chokes." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/9mmdtr.

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碩士
國立成功大學
資源工程學系
107
In this study, molding chokes using FeSiCr alloy powder as the raw material were prepared by gel casting, and the structures and magnetic properties of the samples prepared by dry pressing and gel casting were compared. The experimental results showed that the low-viscosity slurry used in the gel casting process can significantly improve the powder filling uniformity in the center of the coil. For the small-sized and high-inductance molding chokes, the problem of the uneven packing in the center of the coils can be effectively solved by using gel casting, thereby protecting the internal coil from being damaged and short-circuited. Therefore, the molding chokes prepared by gel-casting have higher inductance and better DC superposition characteristics than those prepared by dry pressing. However, if the viscosity of the slurry for the gel casting is too high, the packing of the center of the coil becomes worse, which leads to a lower inductance value. The proportion of the liquid binder used in the gel casting is also lower than that in molding, resulting in a higher initial permeability and the same or higher mechanical strength than that prepared by molding due to the more homogeneous distribution of the binder. It shows that molding chokes made by gel casting has a great potential.

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Ho, Su-Han, and 何思翰. "Powder Compound Development for the Casting Mold Manufacturing with Rapid Prototyping Technology." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/52430507230291120233.

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碩士
國立成功大學
航空太空工程學系碩博士班
94
The rapid prototyping has speed up production, research and development. In all kinds of the rapid prototyping, the three dimensional printer (3DP) is convenient, quick, easy, and accurate in plaster-based rapid prototyping system. Generally, the gypsum-based powder is the familiar material to use in the plaster-based 3DP. Because of the plaster-based powder still can not produce all kind of the casting molds on the industry, it is necessary to develop the powder compound suitable to produce the casting mold. 　This study bases on powder material to design the powder compound which has two different reactive mechanisms. It will discuss the relation between the composition of the powders and the powder property, such as the powder particle size distribution, apparent density and angle of repose. From the result in this study, the strength of green part built by the reaction of both sodium silicate and carbon dioxide is risen to 1.3 MPa. This result is eminently and can spread the materials application in 3DP and the development in the casting mold production.

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黃楹昌. "Development of manufacturing process by the marriage of powder compaction and casting." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/33571819349772018888.

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Bhardwaj, Pooja. "Characterization of carbonaceous materials with respect to mold powder design for continuous casting of steel." 2007. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=452887&T=F.

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Masikane, Muziwenhlanhla Arnold. "Investigation into the microstructure and tensile properties of unalloyed titanium and Ti-6Al-4V alloy produced by powder metallurgy, casting and layered manufacturing." Thesis, 2016. http://hdl.handle.net/10539/20060.

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A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, July 2015
ABSTRACT Solid titanium (Ti) and Ti-6Al-4V (wt.%) materials were fabricated from powders using spark plasma sintering (SPS), cold isostatic press (CIP) and sinter, layered (rapid) manufacturing, centrifugal and vacuum casing. ASTM Grade 4 Ti, Al and V, 60Al-40V (wt.%) and the pre-alloyed Ti-6Al-4V powders were used as starting materials. The solid Ti and Ti-6Al-4V materials produced by the SPS were compared to the CIP and sinter method on the basis of density, microstructure and chemistry. The materials produced by the CIP and sinter method were also compared to those produced by vacuum casting method on the basis of microstructure, oxygen pick-up, chemistry and room temperature tensile properties. Centrifugal casting was compared to the vacuum casting technique on the basis of microstructural homogeneity. Rapid manufacturing was compared to SPS and CIP and sinter on the basis of microstructural homogeneity, density and tensile properties. The tensile properties of all materials were also compared to their commercial counterparts to investigate the effect of interstitial oxygen. The technology resulting in materials with superior properties was finally identified as most promising for commercial production of Ti-based materials. On the basis of densification, the SPS method appears superior compared to the CIP and sinter and rapid manufacturing method due to the benefit of pressure aided sintering, while the rapid manufacturing method is superior to the CIP and sinter method due to the use of a high power laser resulting in high densification rates. In cases where microstructural homogeneity is the key requirement, the CIP and sinter and rapid manufacturing methods appear superior compared to the SPS method due to longer isothermal holding time and higher sintering temperature and the use of pre-alloyed Ti-6Al-4V powder, respectively. On the basis of oxygen pick-up and additional contamination, the vacuum casting route is inferior due to the tendency of melt-crucible interaction, resulting in the dissociation of ZrO2 and subsequent pick-up of O and Zr. Based on the homogeneity of the microstructure, centrifugal casting is better than vacuum casting. The ductility of vacuum cast Ti was better than that of CIP and sintered Ti, possibly due to limited diffusion of oxygen from the crucible compared to oxygen absorbed from the controlled atmosphere during CIP and sinter. The vacuum casting of the Ti-6Al-4V alloy resulted in dissolution of oxygen and Zr due to melt-crucible interaction. Hence the ductility was worse compared to the alloy produced by CIP and sinter. The rapidly manufactured Ti-6Al-4V specimens exhibited superior ductility and strength compared to all alloys produced by other methods due to the use of high purity starting powder. The tensile properties of these specimens were also comparable to standard requirements. The similarity of the tensile properties of wrought Ti-6Al-4V alloy reported in the literature was an indication of limited oxygen pick-up during rapid manufacturing. Therefore based on low oxygen pick-up, microstructural homogeneity, high density and superior tensile properties, the rapid manufacturing route appears to be the most promising approach for commercial processing of titanium based materials.

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Li, HsienChien, and 李賢建. "Study of Rapid Tooling for Thin Wall Product Development using Aluminum-Epoxy Compound Molding, Powder Metallurgy and Investment Casting Technologies." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/90505701021503127802.

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碩士
國立臺灣科技大學
機械工程系
87
The purpose of this research is to focuses on tooling industry to provide a solution and concept of rapid tooling in both temporally mold and production mold. There are two goals in this research: the process development and implement using aluminum-epoxy compound molding in precision thin wall product; the possibility study using powder metallurgy and investment casting techniques in production mold. In order to solve problems raised by the warping of the RP part because of the thin wall design, this study has proposed a venerable process to rebuild the parting line as well as to control the thickness of the molded part. The results shown that the accuracy of the testing part could be as little as 0.1mm and have been successfully operated in a small bench of injection. In general, the economic and speed requirement could be achieved by using aluminum-epoxy compound mold, but the mold life is much shouter than conventional steel mold. The second stage of the research is the possibility study of rapid tooling technology by using powder metallurgy and investment casting technologies in mold building. Both cold compaction and cold isostatic pressing methods; have been applied as the typical powder metallurgy technology and lost wax process method has been used as the typical investment casting technology. All of them have shown that the permanent mold is possible being built by the above rapid tooling technology.

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29

Pinheiro, Carlos A. M. "Mould thermal response, billet surface quality and mould-flux behaviour in the continuous casting of steel billets with powder lubrication." Thesis, 1997. http://hdl.handle.net/2429/8560.

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The main objectives of this study were to examine mould thermal response and billet surface quality during continuous casting of steel billets with powder lubrication, and to compare with oil lubrication. Measurements were carried out on an operating billet caster to determine mould-wall temperature profiles for different mould-flux types, mould coolingwater velocity, oscillation frequency and steel grade. The trial involved data acquisition on mould displacement, casting speed, metal level and mould powder temperature field. In addition, mould powder consumption and liquid flux pool depth were also measured. An inverse heat conduction model was developed to determine mould heat flux from measured mould wall temperatures. Existing mathematical models were utilized to investigate mould/billet binding and mould taper. Results from plant measurement, mathematical models and billet sample evaluation were used to compare mould-powder and oil casting in terms of mould thermal response, transverse depression, rhomboidity, oscillation mark and mould level variation. Finally, a mathematical model was developed to analyze the influence of mould-flux properties and feeding strategies on melting behaviour. This work has led to a very comprehensive understanding of mould thermal response and mould-related quality problem in billet casting with powder lubrication. Transverse depressions were found to be formed in steel grades with high coherency temperature due to metal level fluctuation. For Boron(Ti)-alloyed medium-carbon steel cast with powder transverse depressions were eliminated due to a substantial decrease in meniscus heat flux, thus producing a thinner, hotter, more flexible shell, and also due to lower metal level fluctuations on account of pouring with SEN. An understanding of the role of titanium and nitrogen on transverse depressions resulted in the establishment of maximum values for these elements. In order to minimize transverse depression in billet casting with oil lubrication the nitrogen content of the steel must be kept below 60 ppm and the titanium content below 0.019%. Mathematical modelling of billet shrinkage, corroborated by billet inspection, showed that excessive mould taper caused the mould to squeeze the solidifying shell which led to the formation of longitudinal depressions. To eliminate this problem a double mould taper with 1.8% m⁻¹ up to 450 mm from the mould top and 0.9% m⁻¹ for the rest of the mould is recommended. Mathematical modelling of mould powder melting has led to further understanding of the response of the molten-flux pool to changes in powder properties, feeding strategies and casting speed.

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30

Hao, Kao Chia, and 高家豪. "Effects of Glass Fiber Powder and Sodium Polyacrylate Composite Addition on the Properties of Backup Slurry and Ceramic Shell Mold for Investment Casting." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/17628346829934216940.

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碩士
國立高雄應用科技大學
模具工程系
97
The effect of glass fiber powder on the properties of backup slurry, and the effect of polyacrylate (PAAS) in the backup stucco on the properties of ceramic shell mold have been studied, repectively. Then, the effects of composite addition of glass fiber powder and polyacrylate (PAAS) on the properties of slurry and ceramic shell mold have also been studied. The main concern of the additive in the backup slurry was its effect on the viscosity, pH , rheology and life of slurry; and for ceramic shell mold, was its effect on green strength (pre-dewax), green strength (post-dewax), hot strength, fired strength and high temperature permeability. The results showed, the addition of PAAS in the backup stucco was in favor of reducing the drying time and also helpful for reducing the time to build ceramic mold, promoting high temperature permeability, reducing fired strength, but decreasing green and hot strength, resulting in not be used this additive alone. The addition of glass fiber powder in the backup slurry could reduce slurry life (slurry viscosity raised); The increased slurry viscosity followed the increase of added amount. The increase of added amount resulted in the decrease of high permeability. The addition of 1wt% glass fiber powder had the highest hot strength, the increase of added amount resulted in the decrease of hot strength. The composite addition of these two additives had a complementary effect; the addition of 2wt% PAAS and 10wt% glass fiber powder were in favor of reducing the drying time, promoting high permeability, and the hot strength of the ceramic shell mold was able to bear the impact of high temperature molten metal.

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31

Zi-JieLin and 林子傑. "Particle Packing in Green Bodies Formed through Slip Casting with Fine Alumina Powders." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/j97rz3.

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32

Ying, Yun-Hao, and 應允皓. "A Low Power Test Compression Scheme- Cool Universal Multi-Casting Scan(CUMC-Scan)." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/66195093097443895425.

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碩士
國立清華大學
電機工程學系
96
We present a scan test methodology – called Cool Universal Multicasting Scan (CUMC-Scan) for not only compressing test data volume but also reducing scan test power. Combining the universal segmented shifting and multi-testing based partial capture, it is the first time to solve the overall scan test power violation under a test compression scheme. CUMC-Scan doesn’t need any support from specific ATPG tool and modification on the existing scan architecture. The experimental results indicate we can reduce 88.6% average power and 34.7% peak power in average for real designs.

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33

Lin, Hsing-huei, and 林幸慧. "Rheology, slip casting, and sintering behavior of submicron alumina powders dispersed with ammonium polyacrylate." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/06600550098925952802.

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碩士
國立成功大學
資源工程學系碩博士班
97
Properties of alumina ceramics are closely connected with the process condition. In which slurry preparation is a key point for colloidal forming. In this study, the dispersion behavior of slurries, the process of slip casting, and the pressureless sintering behavior have been discussed by changing the formulation of slurries, including dispersant amount, solid loading, and pH adjustment. In terms of characteristics of slurries, the results show that viscosity could decrease effectively by the 75% coverage of polymer on particle surfaces, and the green forming is facilitated by suitable amounts of free polymer. 1 wt% of the optimal dispersant amount is selected, at which viscosity of the slurry is low, the saturated adsorption is achieved, and the green density is the highest. In addition, the adsorption of the polymer (PAA-NH4) on alumina particles is a reversible reaction. An adsorption or desorption will occurs with the change of pH. In terms of green forming and sintering behavior, greens made from slurries with higher solid loading show broader temperature range of sintering shrinkage, however the sintering process is complete at a lower temperature. The dilatometer results suggest that the mean pore size of the green is smaller but the pore size distribution is broader. There is a suitable range of solid loading for slip casting. In this study, the highest relative density 99.5% and the best transmittance is achieved at the sintering condition of 1400oC/4 h from the sample which solid loading is 30 vol% and the dispersant amount is 1 wt%. Compared with the single-step, two-step, and no pH adjustment, we found the flocculation degree of slurries follows the order: pH 4.4 > two-step > pH 10 > pH 9 (nature pH). The interparticle energies under different conditions is calculated theoretically, and factors which affect the interparticle flocculated situation is studied. The experiment results could be well interpreted by the calculated interparticle energies.

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34

Chang, Kai-ting, and 章凱婷. "A Study of Carbonate Mineral Powders Additives on the Collapsibility of Ceramic Shell Mould for Investment Casting." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/22e64u.

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碩士
國立臺北科技大學
資源工程研究所
97
An investment casting mould consists of individual layers of fine refractory material and granular refractory material held together by a binder that has been set to a rigid gel. The investment casting technique has tremendous difficult in removal shell completely. The effects of the carbonate mineral powders additive on the collapsibility of the primary and backup slurries have been studied. Green strength, fired strength, porosity and permeability between the additive and non-additive carbonate mineral powder in ceramic shell mould were studied. These carbonate mineral powders decomposed from temperature above 850℃ and as a result of the reaction products of CaO and CO2. Due to CO2 dissipated and produced expansion calcium hydroxide as the reaction of CaO and H2O, the ceramic shell mold was increased the porosity and permeability, and thus effected on green and fired strength of the ceramic shell. Therefore, the ceramic shell mold can be removed easier from cast materials.

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35

Correia, Ana de Fátima Durão. "The power of the Genitrix - Gender, legitimacy and lineage: Emma of Normandy, Urraca of León-Castile and Teresa of Portugal." Master's thesis, 2015. http://hdl.handle.net/10451/24466.

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Durante a Idade Média, o papel e poder da mulher como rainha não é só ambíguo e limitado mas também em permanente fluxo de transformação. Para rainhas do século XI e XII, como Emma da Normandia (Emma Ælgifu), Urraca de Leão e Castela e Teresa de Portugal, a afirmação do seu status, tanto real como social, dependia, não só da sua identidade como individuo consagrado e detentor de um cargo, mas também do ofício desempenhado ao lado do elemento masculino. Os mecanismos regentes visavam, em última instância, uma partilha de poder e, porém, os percursos de vida de Emma, Urraca e Teresa e as acções tomadas pelas mesmas afirmaram-nas como autoridades individuais, gerando conflito com o entendimento intelectual e governativo na época, de maioria (se não inteiramente) masculina. Dificuldades de análise e a multiplicidade de papéis e facetas das rainhas da Idade Média tornam necessárias abordagens inovadoras para decorrer sobre esta discussão sobre poderes e títulos. Os estudos de género oferecem possibilidade para construir pontes de diálogo entre culturas, espaços e tempos. As três personagens referidas são precisamente exemplo desta interação. Foram três mulheres, filhas, mães, esposas e rainhas que colocaram modelos e realidades em debate, compelindo a mudanças e/ou adaptações nas regras impostas ao seu género pelos cargos e papéis desempenhados. A fim de melhor compreender o poder destas mulheres e a sua importância para a história e para o género, propomo-nos analisar e contextualizar as várias identidades que se agruparam no título de cada uma das rainhas - domina, mater regis, regina, conlaterana regis, imperatrix - com o objectivo de as enquadrar num espaço de diálogo e interdisciplinaridade entre o mundo Anglo-Saxónico e o Ibérico. Pretende-se igualmente compreender a relação que estabeleceram com os seus filhos como suas genitrix, por modo a verificar qual o contributo e reconhecimento inegável que tiveram na transmissão e legitimação de poderes de gerações futuras.
Abstract: During the middle Ages, the role and powers of women as queens suggested not only ambiguity and limitation, but also a permanent flux of transformations. For queens of the eleventh and twelfth-century like Emma of Normandy (Emma Ælgifu), Urraca of Leon-Castile and Teresa of Portugal, the confirmation of their status, both royal and social, relied not only on their identity as consecrated individuals and owners of an office, but it also depended on how that office was carried out beside its masculine counterpart. The current mechanisms were designed ultimately for a share in power, and yet the life paths of Emma, Urraca and Teresa and the actions they took confirmed them as individual authorities, generating a conflict with the intellectual and government understanding of their time, in its majority (if not entirely) masculine. Difficulties of analysis and the multiplicity of roles and faces of middle ages’ queens call out for creative approaches especially in discussions concerning powers and titles. Gender studies offer the possibility to build communicational bridges between culture, time and space. These three characters in this study are examples of this interaction. They were three women, daughters, mothers, wives and queens, that forced models and realities into debate, and called out for changes and /or adaptations to rules imposed to their gender by their performed offices and roles. Aiming for a better understanding of the power of these women and its importance to history and to gender, we propose to analyze and contextualize their lives and the various identities that were gathered in the title of each one of the queens – domina, mater regis, regina, conlaterana regis, imperatrix –with the intend to create a space where dialogue and interdisciplinarity between the Anglo-Saxon world and the Iberian can converge. Furthermore, it is our purpose to understand the relationship they established with their sons as their genitrix, and thus verify their part in the transmission of powers and legitimacy to future generations.

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36

Rowe, Danelle. "Power and oppression: a study of materialism and gender in selected drama of Caryl Churchill." Diss., 2003. http://hdl.handle.net/10500/1286.

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Caryl Churchill, the most widely performed female dramatist in contemporary British theatre, is a playwright preoccupied with the dissection of the traditional relations of power. She challenges social and dramatic conventions through her innovative exploration of the male gaze, the objectification of women, the performativity of gender, and women as objects of exchange within a masculine economy. In so doing, Churchill locates her concerns in the area of `materialism and gender'. Churchill explicates a socialist-feminist position by pointing directly at the failure of liberal feminism. The lack of a sense of community among women, highlighted by Churchill's portrayal of women such as Marlene in `Top Girls', forms a critical aspect of Churchill's work. Her drama re-iterates how meaningful change is impossible while women continue to oppress one another, and while economic structures perpetuate patriarchy. Altered consciousness, aligned to socio-political re-structuring, is necessary for both the oppressors and the oppressed, in a society where too much emphasis has been placed on individualism. The outspoken hope for a transgression of the conventional processes of identification and other omnipresent, oppressive socio-political phenomena, is a strong aspect of Churchill's work. Her plays reveal how signs create reality rather than reflect it, and she uses Brechtian-based distancing methods to induce a critical examination of gendered relations. Time-shifting, overlapping dialogue, doubling and cross-casting are used by Churchill to manipulate the sign-systems of the dominant order. Cross-gender casting, Churchill's most widely reviewed dramatic device, is employed to destabilise fixed sexual identities determined by dominant heterosexual ideology. She calls into question the traditional sign `Woman' - which is constructed by and for the male gaze - and addresses the marginality of the female experience in a non-linear framework. Although dealing with serious issues, Churchill's plays are often executed in a style that is at once amusing and thought-provoking to exclude the possibility of didacticism. With her skilful use of language and innovative techniques as her highly effective instruments, Churchill accomplishes her broader purpose with originality. In its originality and complexity, her drama is in itself a `new possibility' for different forms.
English Studies
M. A. (English)

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37

Sevastopolev, Ruslan. "Effect of conformal cooling in Additive Manufactured inserts on properties of high pressure die cast aluminum component." Thesis, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-50949.

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Additive manufacturing can bring several advantages in tooling applications especially hot working tooling as high pressure die casting. Printing of conformal cooling channels can lead to improved cooling and faster solidification, which, in turn, can possibly result in better quality of the cast part. However, few studies on advantages of additive manufactured tools in high pressure die casting are published.The aim of this study was to investigate and quantify the effect of conformal cooling on microstructure and mechanical properties of high pressure die cast aluminum alloy. Two tools each consisting of two die inserts were produced with and without conformal channels using additive manufacturing. Both tools were used in die casting of aluminum alloy. Aluminum specimens were then characterized microstructurally in light optical microscope for secondary arm spacing measurements and subjected to tensile and hardness testing. Cooling behavior of different inserts was studied with a thermal camera and by monitoring the temperature change of cooling oil during casting. Surface roughness of die inserts was measured with profilometer before and after casting.Thermal imaging of temperature as a function of time and temperature change of oil during casting cycle indicated that conformal insert had faster cooling and lower temperature compared to conventional insert. However, thermal imaging of temperature after each shot in a certain point of time showed higher maximum and minimum temperature on conformal die surface but no significant difference in normalized temperature gradient compared to the conventional insert.The average secondary dendrite arm spacing values were fairly similar for samples from conventional and conformal inserts, while more specimens from conventional insert demonstrated coarser structure. Slower cooling in conventional insert could result in the coarser secondary dendrite arm spacing.Tensile strength and hardness testing revealed no significant difference in mechanical properties of the specimens cast in conventional and conformal die inserts. However, reduced deviations in hardness was observed for samples cast with conformal insert. This is in agreement with secondary dendrite arm spacing measurements indicating improved cooling with conformal insert.Surface roughness measurement showed small wear of the inserts. More castings are needed to observe a possible difference in wear between the conventional and conformal inserts.Small observed differences in cooling rate and secondary arm spacing did not result in evident difference in mechanical properties of the aluminum alloy but the variation in properties were reduced for samples cast with conformal cooling. Future work may include more accurate measurement of cooling behavior with a thermocouple printed into the die insert, casting of thicker specimen for porosity evaluation and fatigue testing and longer casting series to evaluate the influence of conformal cooling on tool wear.

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Dissertations / Theses on the topic 'Casting powder'

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