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Dissertations / Theses on the topic 'Induction melting'
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Liu, Zhongyi. "Phase transformations in the intermetallic compound ZrCu." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246733.
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Kargahi, Mohammad R. "Use of conducting crucibles in medium-frequency induction melting of non-ferrous metals." Thesis, Loughborough University, 1987. https://dspace.lboro.ac.uk/2134/28091.
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Carbon-bonded silicon carbide and clay-bonded graphite crucibles are used in non-ferrous induction melting furnaces. Silicon carbide crucibles especially have encountered premature failure when used at high power densities and operating frequencies. This is thought to be related to their non-uniform properties. To gain a more thorough understanding of the problem, an equivalent circuit analysis has been applied to the composite load of crucible and metal charge.
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Paun, Matthias Stephan [Verfasser], Martin [Akademischer Betreuer] Lerch, Matthias [Akademischer Betreuer] Bickermann, and Manfred [Akademischer Betreuer] Mühlberg. "Single crystal growth of high melting oxide materials by means of induction skull-melting / Matthias Stephan Paun. Betreuer: Martin Lerch. Gutachter: Matthias Bickermann ; Manfred Mühlberg." Berlin : Technische Universität Berlin, 2015. http://d-nb.info/1078666601/34.
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Quadling, Amanda Gail. "The role of aggregates in the thermal stability of Mg-PSZ refractories for vacuum induction melting." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/28684.
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Mg-PSZ refractories used as vacuum induction melting crucibles are particle-reinforced composites with aggregate and matrix phases comprising fused zirconia. Three commercial varieties were cycled eight times to service temperatures and their microstructural and thermomechanical evolution investigated, with focus placed on the aggregate populations. Two refractories, with large aggregates of similar size, were found to retain stiffness after cycling but in the refractory containing aggregates with high stabiliser levels, reaction between the stabiliser and Al and Si impurities produced secondary phases. Volume changes accompanying formation of these phases, and subsequent thermal expansion mismatches, led to aggregate break-up with consequent reductions in refractory toughness and strength. Secondary phases developed only rarely in the aggregates (with lower levels of stabiliser) of the second refractory. These aggregates remained intact and the refractory retained its toughness and strength. A third refractory contained small, unstabilised aggregates in a stabilised matrix and the strain mismatches that ensued during polymorphic transformation damaged microstructural interfaces. Refractory stiffness halved within eight cycles and toughness and strength were lost. All three refractories displayed R-curve behaviour and quasi-stable fracture curves were observed during bend tests. The study shows that when using fused zirconia aggregates to design refractories, engineers need to i) limit stabiliser concentrations - a difference of just ± 1 wt% Mg (in the presence of impurity elements) may determine whether secondary phase formation occurs and ii) eliminate alumina and silica impurities when possible through substitution of zircon sand with baddeleyite as the source for fused zirconia.
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Nounezi, Thomas. "Light Weight and High Strength Materials Made of Recycled Steel and Aluminum." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20523.
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Recycling has proven not only to address today’s economical, environmental and social issues, but also to be imperative for the sustainability of human technology. The current thesis has investigated the feasibility of a new philosophy for Recycling (Alloying-Recycling) using steel 1020 and aluminum 6061T6. The study was limited to the metallurgical aspects only and has highlighted the potential of recycled alloys made of recycled aluminum and steel to exhibit substantially increased wear resistance and strength-to-weight ratio as compared to initial primary materials. Three alloy-mixtures are considered: TN3 (5wt% 1020 +95wt% 6061T6); TN5 (0.7wt% 1020 + 99.3wt% 6061T6); and TN4 (10wt% 6061T6 + 90wt% 1020). A Tucker induction power supply system (3kW; 135-400 kHz) is used to melt the alloy mixtures for casting in graphite crucibles. Heat treatment of the cast samples is done using a radiation box furnace. Microscopy, Vickers hardness and pin-on-disc abrasive wear tests are performed.
Casting destroyed the initial microstructures of the alloys leading to a hardness reduction in the as-cast and solution heat-treated aluminum rich samples to 60 Hv from 140 Hv. Ageing slightly increased the hardness of the cast samples and provided a wear resistance two times higher than that of the initial 6061T6 material. On the steel rich side, the hardness of the as-cast TN4 was 480 Hv, which is more than twice as high as the initial hardness of steel 1020 of 202 Hv; this hints to strong internal and residual stress, probably martensite formation during fast cooling following casting. Solution heat treatment lowered the hardness to the original value of steel 1020, but provided about ten (10) times higher wear resistance; this suggests higher ductility and toughness of normalised TN4 as compared to 1020. In addition, TN4 exhibits about 25% weight reduction as compared to 1020.
The actual recycling process and the effect of non-metallic impurities shall be investigated in future works. Also, the casting and heat treatment processes need to be improved.
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Bourrou, Rémi. "Développement d'un modèle numérique magnéto-thermo-hydrodynamique pour un procédé de fusion par induction d'un mélange métal-verre." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI070.
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Dans le procédé PIVIC, ayant pour objectif le conditionnement de déchets nucléaires technologiques mixtes, un bain de métal et de verre est maintenu en fusion par induction électromagnétique. La conductivité électrique du verre étant relativement faible, les forces de Laplace et le chauffage par effet Joule sont uniquement actifs dans le métal. Le verre est donc mis en mouvement et maintenu en fusion par son contact avec la phase métallique, ce qui complexifie le pilotage du procédé, notamment lorsque ce matériau commence à figer. L’objectif de cette thèse est d’étudier le couplage magnéto-thermo-hydrodynamique dans le procédé afin de comprendre le mécanisme à l’origine du figeage du verre et ainsi de pouvoir l’éviter. Pour ce faire, divers outils de modélisation numérique sont utilisés afin de représenter les phénomènes thermiques, hydrodynamiques et électromagnétiques dans le procédé.Un point crucial à prendre en compte est la déformation de la surface du métal par la pression magnétique, ce qui créé un dôme pouvant émerger de la phase de verre. Dans un premier temps, les transferts thermiques sont écartés pour la modélisation numérique. Le modèle développé consiste en un couplage entre COMSOL Multiphysics® (induction EM) et ANSYS Fluent® (mécanique des fluides en régime turbulent). Afin de représenter la déformation des interfaces entre les fluides, une formulation triphasique du modèle Volume Of Fluid (VOF) a été utilisée. Les résultats numériques obtenus sont comparés aux mesures effectuées sur le prototype du procédé. Cette étude met en évidence les paramètres ayant un impact important sur l’élaboration ainsi qu’un phénomène d’entrainement d’air entre les deux liquides.Dans un second temps, les phénomènes thermiques sont ajoutés au modèle numérique. Un modèle spécifique est développé pour représenter le rayonnement au niveau de la surface libre des liquides tout en utilisant le modèle VOF. La répartition des flux de refroidissement ainsi que la température dans le creuset obtenues avec ce modèle plus complet sont comparées avec le prototype. L’impact de la masse de verre dans le creuset sur le comportement thermique du procédé est finalement étudiéIn the PIVIC process, aimed to package mixed technological nuclear wastes, a metal-glass bath is melted by electromagnetic induction. The electrical conductivity of the glass being relatively low, the Lorentz forces and the Joule heating are present only in the metal. The glass is therefore put in motion and heated by its contact with the metallic phase, which complicates the control of the process, especially when this material starts to freeze. The goal of this thesis is to study the magneto-thermo-hydrodynamic coupling in the process to understand the freezing mechanism in order to avoid it. To this end, several numerical modelling tools are used in order to represent the thermal, hydrodynamic, and electromagnetic phenomena in the process. An essential point to take into account is the deformation of the metal’s free surface by the magnetic pressure, producing a dome that can emerge from the glass phase.For the first stage of the numerical modelling, the heat transfers are discarded. The model developed consists in a coupling between COMSOL Multiphysics® (EM induction) and ANSYS Fluent® (turbulent fluid flow). In order to represent the deformation of the interfaces between the fluids, a three phase Volume Of Fluid (VOF) model is used. The results of the numerical model are compared to the measures performed on the prototype of the process. The study highlights the parameters having the most impact on the process and also raises an air entrainment phenomenon between the liquids.At the second stage, thermal phenomena are added to the numerical model. A separate model is developed to represent radiative heat transfers at the free surface of the liquids with the VOF model. The repartition of the cooling fluxes and the temperature inside the crucible are compared between this numerical model and the prototype. Finally, the impact of the glass mass in the crucible on the thermal behavior of the process is studied
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Quéméner, Olivier. "Etude et mise en oeuvre d'un procédé de recyclage par induction d'alliages métalliques." Grenoble INPG, 1993. http://www.theses.fr/1993INPG0124.
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Le procede de fusion par creuset froid inductif est une technique en voie de developpement industriel ayant pour application principale la fusion d'alliages metalliques. L'objet de cette these est la mise au point d'un procede de recyclage de copeaux de laiton, recyclage delicat a obtenir par les moyens traditionnels. La premiere partie traite de la conception originale d'une installation de fusion a creuset froid inductif, fonctionnant a 50 hertz. Apres une phase de dimensionnement par modelisation numerique et experimentation, il est procede a l'etude des elements optimisant la fusion: forces de levitation electromagnetiques, systeme concentrateur de champ. Le brassage electromagnetique, a l'origine de l'assimilation rapide des copeaux, fait l'objet d'une etude analytique, numerique et experimentale. L'exploitation des resultats experimentaux, thermiques et electriques, permet d'obtenir la caracterisation complete de l'installation au niveau energetique, et notamment la determination du rendement reel du prototype. La seconde partie traite du controle de la coulee du metal liquide, au moyen d'un dispositif statique a induction: l'amorcage de la coulee est obtenu par application d'un champ moyenne frequence, l'arret de la coulee met en uvre des phenomenes couples de thermique avec changement de phase et de mecanique des fluides, qui font l'objet d'une modelisation numerique. Le pilote industriel realise a ete installe aux laminoirs du dauphine (etablissements bonmartin) a domene, isere
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Gosset, Didier. "Modélisation des transferts de matière et de la précipitation inclusionnaire lors de l'élaboration du Marphy 17 au four à induction sous vide." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL129N.
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Ce travail, qui s'inscrit dans le thème général de la maitrise des interactions métal liquide-réfractaire-atmosphère, a consiste à modéliser les transferts de matière et la précipitation inclusionnaire lors de l'élaboration au four à induction sous vide du Marphy 17. Le mouvement engendré par l'action des forces de brassage est calculé à l'aide d'un modèle qui résout également les équations de transports des différents solutés (ca, al, mg, o, c) par diffusion, convection et turbulence. Une attention particulière est portée au phénomène de volatilisation à la surface libre. La validation du modèle hydrodynamique est réalisée dans un four pilote à partir de comparaisons entre les déplacements d'une particule posée à la surface et le mouvement calculé du liquide. Les simulations mettent en évidence l'importance d'un calcul précis de l'intensité de la turbulence à la surface libre du bain métallique. Le modèle de transfert de matière, pour sa part, a permis de simuler des expériences de volatilisation du manganèse dissous dans le fer liquide. En couplant le modèle de transfert de matière à un modèle d'équilibre thermodynamique développe a l'IRSID, il est possible d'obtenir au cours du temps et en tout point du bain la composition du métal liquide ainsi que la composition et la nature des inclusions formées. Cette modélisation permet également de représenter, de manière simplifiée, les transferts de matière aux interfaces métal liquide-réfractaire. Les principaux résultats obtenus à l'aide de cette démarche sont présentés et discutées
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Lotto, André Alexandrino. "Remoção de fósforo de silício por fusão a vácuo." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-26122014-171209/.
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A demanda por energia fotovoltaica vem aumentando a razão de mais de 20% ao ano no mercado internacional nos últimos dez anos. O silício com pureza entre 99,999% e 99,99999% é utilizado na fabricação de células fotovoltaicas. O silício metalúrgico tem pureza entre 98,5% e 99%. Este estudo visa investigar o refino a vácuo como um processo alternativo de menor custo para se obter o silício para células fotovoltaicas. Este processo pode remover o fósforo do silício, que é um dos elementos prejudiciais à célula fotovoltaica. Isso permitiria agregar valor à produção brasileira de silício metalúrgico, que alcança um preço de aproximadamente US$2,5 por quilo, enquanto o silício para células fotovoltaicas varia entre US$20 e 60 por quilo. Foram realizados experimentos de fusão em forno de indução a vácuo, variando parâmetros como temperatura, tempo e pressão. O teor de fósforo caiu de 33 ppm para cerca de 0,1 ppm e os resultados foram comparados com um modelo matemático da literatura. Conclui-se que o refino por este processo é tecnicamente viável.The demand for photovoltaics is increasing at a ratio over 20 % per year in the international market in the last ten years. Silicon with purity of 99.999 % and 99.99999 % is used in the manufacture of photovoltaic cells. The purity of metallurgical silicon is between 98.5% and 99%. This study aims to investigate the vacuum refining process as a lower cost alternative to obtain silicon for photovoltaic cells. This process can remove phosphorus from silicon, which is a harmful element to the photovoltaic cell. This would add value to Brazilian production of metallurgical silicon, that reaches a price of approximately U.S.$ 2.5 per kilogram, while the silicon for photovoltaic cells varies between U.S.$ 20 and 60 per kilo . Melting experiments were performed in a vacuum induction furnace by varying such parameters as temperature, time and pressure. The phosphorus content dropped from 33 ppm to about 0.1 ppm and the results were compared with a mathematical model from literature. It is concluded that refining of this process is technically feasible.
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Barták, Tomáš. "Fyzikálně-chemické aspekty přípravy intermetalik TiAl obsahujících niob." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-233383.
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Prezentovaná práce se zabývá vakuovým indukčním tavením intermetalické slitiny Ti-46Al-7Nb (at. %) v žáruvzdorných kelímcích na bázi Y2O3. Byla provedena série taveb pro teploty přehřátí taveniny 1630, 1680 and 1730 C a při různých dobách výdrže na této teplotě v rozmezí 5 až 30 minut. Ze slitin ztuhlých v tavících kelímcích byly připraveny metalografické výbrusy, které sloužily k hodnocení mikrostruktury a vyhodnocení složení fází. Pro získání těchto dat byly použity metosy elektronové mirkoskopie SEM a EDS. Kvantitativní hodnocení mikrostruktury, zejména obsahu oxidické faze ve slitině, bylo provedeno pomocí software Adaptive Contrast Control (ACC). Analýza obsahu kyslíku ve ztuhlé slitině byla provedena metodou IGF (fúze v inertním plynu). V této práci jsou pochody na rozhraní slitina/oxidický kelímek posuzovány také z termodynamického hlediska a to s použitím aktivit jednotlivých složek v systému. Data prezentovaná v této práci mohou být použita pro nastavení a optimalizaci procesů tavení intermetalik TiAlNb.
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Sedláková, Jitka. "Převedení výroby litiny z kuplovny na indukční pec." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-228991.
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The subject of this work is to validate the possibility of managing the cast iron strength through residual Mg content and to determine methodically whether it is possible to exploit this technology in a foundry. It is another subject to determine the economics of the exchange of cupola furnace for electric induction furnace and methodically assess the possibilities of melting in the electric induction furnace.
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Kuběnová, Monika. "Příprava a martenzitické transformace slitin na bázi NiTi." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-233380.
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Cíle této práce jsou: (i) vyhodnocení vlivu Y2O3 kelímku na kontaminaci indukčně tavené NiTi slitiny obohacené niklem, (ii) optimalizace podmínek, při kterých jsou tavby uskutečněny a (iii) získání nových DSC a 3D AP dat o vlivu vodíkové atmosféry na martenzitickou transformaci a na strukturu NiTi slitin obohacené niklem s tvarovou pamětí. Byly provedeny následující experimenty: – Pět taveb bylo navrženo a provedeno tak, aby byla snížena maximální tavící teplota. – Pět přetaveb bylo uskutečněno při teplotě 1500 C s dobou výdrže 2, 10 a 20 minut a při teplotách 1450 C a 1550 C s 20 minutovou dobou výdrže. Experiment byl navržen tak, aby byl vyšetřen vliv tavící teploty a doby výdrže na obsah kyslíku pocházejícího z kelímku Y2O3 v tavenině. – Tepelné zpracování NiTi slitiny obohacené niklem v režimu I (žíhání) a v režimu II (kombinace žíhání se stárnutím) pod atmosférou vodíku, směsi vodíku s héliem a pod referenční atmosférou čistého hélia. Získané výsledky jsou: – Navržené tavící postupy vedou ke snížení maximální tavící teploty a to z 1800 C na 1400 C. Přesto toto velké snížení maximální tavící teploty nevedlo k významnému poklesu obsahu kyslíku. – Během přetavby uskutečněné při teplotě 1500 C s dobou výdrže 2 minuty se obsah kyslíku navýšil o trojnásobek jeho počáteční hodnoty a příliš se nelišil od obsahu kyslíku naměřeného ve slitině, která byla přetavena při stejné teplotě s dobou výdrže 10 minut. K nárustu o čtyřnásobek počáteční hodnoty obsahu kyslíku došlo u přetavby vedené na teplotě 1450 C po dobu 20 minut a hodnota obsahu kyslíku se příliš nelišila od hodnoty naměřené ve slitině přetavené při teplotě 1550 C se stejnou dobou výdrže. – S rostoucím parciálním tlakem vodíku dochází k potlačení jednokrokové martenzitické transformace. Významný pokles výšky DSC píku nastává při parciálním tlaku 100 mbar. 3D AP analýza odhalila, že nedochází k žádné lokální změně koncentrace a nebo pozic niklových a titanových atomů ve vzorku, který byl žíhán v režimu I ve vodíku. Bylo objeveno, že vodík tvoří stabilní intersticiální tuhý roztok v NiTi B2 mřížce, kde vytváří systém nanodomén s obsahem vodíku vyšší než 10 at%.
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Conti, Alfredo. "Tecniche della manifattura additiva - applicazioni in ambito aeronautico e aerospaziale." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13306/.
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Il potenziale delle nuove tecnologie digitali applicate al settore industriale ha consentito di ridurre enormemente la durata dei cicli produttivi grazie alla rapida gestione di quantità di dati sempre più considerevoli attraverso l’introduzione delle Macchine a Controllo Numerico (Computer Numerical Control – CNC).
Nel corso delle ultime tre decadi, l’industria manifatturiera ha subito notevoli e sostanziali cambiamenti grazie ad una sempre più forte connessione con il mondo dell’informatica.
La più grande rivoluzione in tale ambito è stata segnata dall’avvento della Manifattura Additiva (Additive Manufacturing - AM), conosciuta sotto diversi nomi, tra i quali Prototipazione Rapida (Rapid Prototyping), Manifattura Rapida (Rapid Manufacturing) o Libera Fabbricazione di Forme (Free Form Fabrication).
Materia di ricerca e sviluppo sin dalla fine degli anni ’80, la Manifattura Additiva consente la creazione di elementi fisici tridimensionali partendo da modelli CAD attraverso la sovrapposizione successiva di materiale strato per strato (layer by layer), offrendo i benefici di una elevata flessibilità geometrica degli elaborati, altrimenti irraggiungibile attraverso le tradizionali tecniche di Manifattura Sottrattiva operanti per asportazione di materiale. In seguito ad intensive ricerche, progressi significativi sono stati fatti nello sviluppo e nella commercializzazione di nuovi ed innovativi processi AM.
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Huaiyu, Yang. "Crystallization of Parabens : Thermodynamics, Nucleation and Processing." Doctoral thesis, KTH, Teknisk strömningslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122228.
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In this work, the solubility of butyl paraben in 7 pure solvents and in 5 different ethanol-water mixtures has been determined from 1 ˚C to 50 ˚C. The solubility of ethyl paraben and propyl paraben in various solvents has been determined at 10 ˚C. The molar solubility of butyl paraben in pure solvents and its thermodynamic properties, measured by Differential Scanning Calorimetry, have been used to estimate the activity of the pure solid phase, and solution activity coefficients. More than 5000 nucleation experiments of ethyl paraben, propyl paraben and butyl paraben in ethyl acetate, acetone, methanol, ethanol, propanol and 70%, 90% ethanol aqueous solution have been performed. The induction time of each paraben has been determined at three different supersaturation levels in various solvents. The wide variation in induction time reveals the stochastic nature of nucleation. The solid-liquid interfacial energy, free energy of nucleation, nuclei critical radius and pre-exponential factor of parabens in these solvents have been determined according to the classical nucleation theory, and different methods of evaluation are compared. The interfacial energy of parabens in these solvents tends to increase with decreasing mole fraction solubility but the correlation is not very strong. The influence of solvent on nucleation of each paraben and nucleation behavior of parabens in each solvent is discussed. There is a trend in the data that the higher the boiling point of the solvent and the higher the melting point of the solute, the more difficult is the nucleation. This observation is paralleled by the fact that a metastable polymorph has a lower interfacial energy than the stable form, and that a solid compound with a higher melting point appears to have a higher solid-melt and solid-aqueous solution interfacial energy. It has been found that when a paraben is added to aqueous solutions with a certain proportion of ethanol, the solution separates into two immiscible liquid phases in equilibrium. The top layer is water-rich and the bottom layer is paraben-rich. The area in the ternary phase diagram of the liquid-liquid-phase separation region increases with increasing temperature. The area of the liquid-liquid-phase separation region decreases from butyl paraben, propyl paraben to ethyl paraben at the constant temperature. Cooling crystallization of solutions of different proportions of butyl paraben, water and ethanol have been carried out and recorded using the Focused Beam Reflectance Method, Particle Vision and Measurement, and in-situ Infrared Spectroscopy. The FBRM and IR curves and the PVM photos track the appearance of liquid-liquid phase separation and crystallization. The results suggest that the liquid-liquid phase separation has a negative influence on the crystal size distribution. The work illustrates how Process Analytical Technology (PAT) can be used to increase the understanding of complex crystallizations. By cooling crystallization of butyl paraben under conditions of liquid-liquid-phase separation, crystals consisting of a porous layer in between two solid layers have been produced. The outer layers are transparent and compact while the middle layer is full of pores. The thickness of the porous layer can reach more than half of the whole crystal. These sandwich crystals contain only one polymorph as determined by Confocal Raman Microscopy and single crystal X-Ray Diffraction. However, the middle layer material melts at lower temperature than outer layer material.QC 20130515
investigate nucleation and crystallization of drug-like organic molecules
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Jang, Dong-Sheng, and 江東昇. "Hydrogen Storage Behavior of the Mg-Ni-M Alloys Synthesized by Vacuum Induction Melting." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/70917337507084707057.
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碩士國立臺灣海洋大學
材料工程研究所
94
The purpose of this thesis is to apply neural network controller to aircraft automatic landing system. Most of the studies regarding flight control are based on conventional modern control theories with optimal or adaptive control methods. Typically these techniques involve linearizing the aircraft dynamics about several operating conditions through out the flight envelope, designing linear controllers for each condition, and gain-scheduling approach. The disadvantages are that it require extensive computations, memory utilization, and memory space. Furthermore, conventional controllers are not capable of handling environmental disturbances. It is noted that existing automatic landing system work reliably only within a carefully specified operational safety envelope. A conventional autopilot has difficulties in severe wind disturbances during the landing phase. Thus, to increase the safety of landing it would be desirable if new method could expand the operational envelope to include safe responses under different environmental conditions. Artificial neural networks, which have the ability to approximate continuous nonlinear functions, offer the potential to overcome these problems. In this study, a multilayer feedforward neural network is applied to the aircraft landing control. The neural network controller can learn different flight conditions off-line. Simulation results show that the trained controller can guide the aircraft landing safely through wind disturbances. The analysis of using different numbers of hidden unit are included. Through the simulations, the combination of the training data and scaling skill are found. Also, strength ranges of wind turbulence and wind shear for a safety landing are suggested.
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Hsu, Chun-Hsiang, and 許竣享. "The Effects of Different Pretreatment Electroless-Nickel-Plating TiC on the Microstructure and Hardness of the Vacuum Induction Melting." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/s58wvp.
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碩士義守大學
材料科學與工程學系
105
Vacuum induction melting (VIM) and hardfacing alloys are currently widely used processes and materials, but to fabricate hardfacing alloy by using VIM and related literature are few. In this study, electroless nickel plated TiC reinforced nickel-based alloy/AISI 4140 steel were produced by VIM. Using Ni-based powders as base material and adding TiC with different pretreatment of electroless nikel plating 1 , 5 wt% , 10 wt% repectively were poured into the 4140 steel crucible, and heated to 1200 oC to make electroless nickel plated TiC renforced Nickel-based alloy/AISI 4140 steel. As revealed by XRD、SEM、EDS and EPMA analysis, we confirmed that the electroless nickel-plated titanium carbide reinforced nickel based alloy microstructure consists mainly of γ-Ni, Ni3B, Ni3Si, Ni31Si12, CrB, Cr7C3, Cr23C6, TiC. The electroless nickel plating can effectively improve the wettability between titanium carbide and nickel-based alloy. In the electroless nickel plating process, as increase of nickel sulfate content will improve the surface coverage of the powder coating. In the sensitization process the titanium carbide particles appear ladder-like structure, this structure can improve the adsorption of nickel ions and the resulting nucleation. Above all, pre-pretreatment condition N with 16ml hydrochloric acid and 4g chloride, anhydrous can have the best result. In the result of hardness test, the hardness increases with the addition of electroless nickel plating titanium carbide particles, and its area fraction also shows an upward trend. In the case of 1 wt% addition, titanium carbide-caused hardening can be observed In addition, the iron atoms are affected by the distribution of iron atoms, large flaw of iron atoms to the nickel-based alloy layer was not hindered, resulting in the decrease in the hardness of the test piece. In the case of 10 wt% electroless nickel plated titanium carbide iron flow was blocked by titanium carbide. Thus, in the case of 10 wt% electroless Ni plated titanium carbide, the overall hardness increase.
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Chen, Zheng-Wen, and 陳政文. "The Effect of Microstructure and Wear Behavior of Addition Electroless Plating TiC Reinforced Nickel-based Alloy by Vacuum Induction Melting." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/03491469135945781739.
Full textAbstract:
碩士義守大學
材料科學與工程學系
102
Electroless nickel plating TiC reinforced Nickel-based alloy/AISI 4140 steel were produced by Vacuum Induction Melting in this thesis. Add 5、10 and 20wt% electroless nickel plating titanium carbide powder into Nickel-based alloy and poured into the 4140 steel crucible then heated to 1200℃ and hold on for 0 and 5 minutes to made electroless nickel plating TiC reinforced Nickel-based alloy/AISI 4140 steel. Dry sliding wear test of the ball-on-disc experiment, with the wear parameters being a fixed load of 0.5 and 1.7kg, sliding velocities of 0.7 m/s, and sliding distance between 100 and 10,000 m to study .As revealed by XRD the presence of γ-Ni、Ni3Si、Ni31Si12、Ni3B、CrB and TiC phase in electroless nickel plating TiC reinforced Nickel-based alloy. Furthermore, XRD analysis also indicated that a trace amount of phosphorus did not affect the microstructure. After electroless nickel of titanium carbide can improve wettability of between titanium carbide and nickel base alloys. With the electroless nickel plating the amount of titanium carbide increases, which also increased the area fraction and hardness.The distribution of hardness can be found electroless add the electroless nickel plating the amount of titanium carbide increases and the smaller influence on the hardness of the iron diffusion. In the early wear 100,500m wear loss increases with addition of electroless nickel plating titanium carbide with wear loss reducing, and can be found the hard particles prevent abrasive path. But in the late wear 1000~10000m wear loss increases with addition of electroless nickel plating titanium carbide with wear loss increases. Due to the electroless nickel plating titanium carbide and nickel-based alloys bondability is poor, and lead to three-body abrasive. In the sliding distance 100~500m mostly based on the wear behavior of abrasion wear and adhesion wear based, and then in the sliding distance 1000~10000m mostly based on the wear behavior of abrasion wear, adhesion wear, surface fatigue wear and oxidation wear based. The results of Wear loss of Add 5wt% electroless nickel plating titanium carbide, heated to 1200℃ and hold on 5 minutes, fixed load of 0.5 and 1.7kg and sliding distance between 5000 and 10,000 m can be found fixed load of 0.5kg Significantly increased,1.7kg decreased. fixed load of 0.5kg, sliding distance 5000~10000m on the wear behavior of severe oxidation wear. Fixed load of 1.7kg on the wear behavior of surface fatigue wear can be found severe oxidation wear lead to the main factor in the rise of wear loss.
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Fan, Bo-Zhi, and 范博智. "The Effect of Process Conditions on Wear Behavior of In Situ TiC Reinforced Nickel-based Alloy by Vacuum Induction Melting." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/mj5c9j.
Full textAbstract:
碩士義守大學
材料科學與工程學系
102
In this study, the use of a vacuum induction melting way production of in situ TiC reinforced Ni-based alloys with Ni-based alloy as base material and then adding Ti and milled graphite powder after 24 hours, so that Ti and graphite produced from TiC in Ni-based alloys, with Ti and graphite addition amount of 5, 10 and 15wt%, the heating temperature of 1200 and 1250 ℃ holding 5 minutes for in situ TiC reinforced Ni-based alloys. Wear test using ball on disk way, wear conditions for the sliding velocity 0.7m/s, the wear load (0.5, 1.2 and 1.7kg), sliding distance (100,500,1000,5000 and 10000m ), explore the effect of the above conditions on the in situ TiC reinforced Ni-base alloy microstructure and wear behavior. The experimental results show of in situ TiC reinforced Ni-based alloys by XRD analysis containing γ-Ni, Ni3Si, Ni31Si12, Ni3B, CrB, M7C3, M3C2, M23C6, TiC, TiB, TiB2. Generation amount of in situ TiC with increasing heating temperature increases with the addition amount of Ti and graphite.In situ TiC reinforced Ni-based alloys in the sliding distance 100~500m mostly based on the wear behavior of abrasion wear and adhesion wear based, and wear behavior for sliding distance 1000m is slightly oxidation wear from abrasion wear and adhesive wear to start the conversion, sliding distance to 5000~10000m wear behavior occurs after differences, wear load 0.5kg conditions is slightly oxidation wear mainly, wear load 1.2kg conditions is slightly oxidation wear based, but there are sporadic oxide film cracked arising from severe oxidation wear, wear load 1.7kg conditions is severe oxidation to wear based. The micro-cracks in the wear subsurface when wear load 0.5 and 1.2kg were passed around along the hard phase, when wear load 1.7kg was passed directly through the hard phase. The hard phase of TiC strengthened Ni base alloys are playing the role of a barrier scratch path, but the protection of the substrate only in that the effect of TiC wear early (sliding distance of 100 to 1000m), which is due to the small particle size of TiC, the stress support area is limited, Although wear debris adhesion can unable to develop oxide film; the other hand the large particle size of chromium carbide, chromium borides and M23X6, although far less than the hardness of TiC, but the stress of supporting a wider area, and can be wear debris adhesion development of oxide film. TiB and TiB2 particle size similar hardness as much as TiC, but its location be limited generation (CrB surface), can only strengthen CrB hardness, enhance the ability of CrB to support stress.
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Wang, Tz-cheng, and 王梓丞. "The Influence of Melting Conditions and Addition of Graphite and Titanium on the Microstructure of Vacuum Induction Fused Nickel-Base Alloy." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/51213352433624336684.
Full textAbstract:
碩士國立臺南大學
材料科學系碩士班
101
In situ formation of TiC particles reinforced Ni-based alloy was prepared by vacuum induction melting in this study. The influence of particle size of graphite(332~935nm), additional amount of titanium and graphite powder(5~15wt%), heating temperature(1150~1250℃), and holding time(0~5min.)on the microstructure of nickel-based alloy. Results indicated that the microstructure of nickel-based alloy, which contains titanium carbide, consists of γ-Ni, Ni3Si, Ni31Si12, Ni3B, CrB, M23C6, M7C3, M3C2, TiC, TiB, and TiB2. It released big amount of titanium and carbon element into nickel-based alloy, caused by the decomposition of chromium carbide and chromium boride in the nickel based alloys. It also depended on the fusion temperature and fusion time. According to the results of WDS and element mapping, it showed that contain simultaneously five element of nickel, chromium, titanium, carbon, boron. It could be the complex carbide M23C6(M=Ni,Cr,Ti) phases. The microstructure exist Ni23C6 phases as a result of the reaction between carbon and γ-Ni. In this experiment contains three different stoichiometric ratio , the different phase made by the different carbon content. During the heating process, makes the grain boundary has melted Ni-Ti solution to form Ni-Ti-C solution, After heating, the Ni-Ti-C solution began to precipitate carbide titanium near the grain boundary. M23C6 phase increased with the elevated temperature and time, the increment of M23C6, M7C3, M3C2, TiB, and TiB2 phase caused the decrement of the Ni3B and CrB phase.
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Huang, Hui-Yu, and 黃惠榆. "The Effects of Electroless-Nickel-Plating TiC and Heating Conditions on the Microstructure and Wear Behavior of the Vacuum-Induction-Melting Ni-based Alloy." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/08026847059830508471.
Full textAbstract:
碩士義守大學
材料科學與工程學系
104
Electroless nickel plating TiC reinforced nickel-based alloy/AISI 4140 steel were produced by vacuum induction melting in this study. Add 1、5 and 10 wt% electroless nickel plating titanium carbide powder into nickel-based alloy and poured into the 4140 steel crucible then heated to 1150、1200℃ and hold on for 0 and 3 minutes to made electroless nickel plating TiC reinforced Nickel-based alloy/AISI 4140 steel. Dry sliding wear test of the ball-on-disc experiment, with the wear parameters being a fixed load of 1.7kg, sliding velocities of 0.7m/s, and sliding distance between 100 and 5000m to study. As revealed by XRD、SEM、EDS and EPMA analysis confirmed that the electroless Nickel titanium carbide reinforced nickel base alloy microstructure containing γ-Ni, Ni3B, Ni31Si12, Ni3Si, CrB, Cr7C3, Cr23C6 and TiC phase.The use of electroless nickel can effectively improve the wettability of between TiC and nickel-based alloy, With the electroless nickel plating the amount of TiC increases, which also increased the area fraction and hardness. Electroless nickel plating TiC phases is not much difference at difference temperatures, and as absorbed by total heat increase in CrC and CrB phases become large, Fe diffusion more obvious. The distribution of hardness can be found electroless add the electroless nickel plating the amount carbide increases and the smaller influence on the hardness of the iron diffusion. In wear test, the wear loss increases with addition of electroless nickel plating TiC with wear loss reducting, In the wear distance 100m and 500m when observed mainly the hard particles prevent abrasive path,the wear mechanisms of scratch、adhesion and slidhtly oxidized abrasion. When 1000m and 2000m will produce oxide membrane protective surface, mainly have adhesive and slidhtly oxidized adrasion, and wear distance to 5000m oxide membrane break froming the three-body abrasion cause wear loss increased, wear behavior is adhesive、slightly oxidized and severely oxidized wear and three-body wear. In the wear test can found the electroless nickel plating TiC add 1wt%, the wear loss will be increases that as temperature add and continue, In addition to titanium carbide hardening phase is less, also by impact of the iron diffusion. The amount of 1wt% is not easy been hampered by the iron diffusion, affect the overall decrease in hardness, during wear, the wear loss increased, while in electroless nickel TiC added amount of 10wt%, diffusion of Fe hampered by the large amount of titanium carbide, is not easy to spread, so hardness and wear loss influenced by temperature conditions.
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Lourens, Leon. "Reduction of iron ore fines in the Ifcon furnace." Diss., 2003. http://hdl.handle.net/2263/27383.
Full textAbstract:
This work involved an investigation into the mechanisms governing the reduction of material in the solids bed of the Ifcon® process. Thermo gravimetric analyses were done to investigate the influence of various operational parameters on the rate of solid state reduction. The experiments were modeled, and model predictions were compared to experimental results. Kinetic data was analised and the reduction rate constants were calculated. The rate constants were used as inputs to a model, which describes the reduction behaviour and temperature profile in a composite solids bed (similar to that in the Ifcon® process). High temperature reduction- and melting tests were done in an 150 kW induction furnace, to simulate final reduction in a solids bed. The temperature profile through the solids bed was measured and results were compared to model predictions. Finally the extent to which solid state reduction occurs in the solids bed was estimated as a function of production rate.Dissertation (MEng (Metallurgical Engineering))--University of Pretoria, 2008.
Materials Science and Metallurgical Engineering
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