Дисертації з теми "Carbides Effect of high temperatures on"
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Wingbrant, Helena. "Development of high temperature SiC based field effect sensors for internal combustion engine exhaust gas monitoring." Licentiate thesis, Linköping University, Linköping University, Applied Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4673.
Повний текст джерелаWhile the car fleet becomes increasingly larger it is important to lower the amounts of pollutants from each individual diesel or gasoline engine to almost zero levels. The pollutants from these engines predominantly originate from high NOx emissions and particulates, in the case when diesel is utilized, and emissions at cold start from gasoline engines. One way of treating the high NOx levels is to introduce ammonia in the diesel exhausts and let it react with the NOx to form nitrogen gas and water, which is called SCR (Selective Catalytic Reduction). However, in order to make this system reduce NOx efficiently enough for meeting future legislations, closed loop control is required. To realize this type of system an NOx or ammonia sensor is needed. The cold start emissions from gasoline vehicles are primarily due to a high light-off time for the catalytic converter. Another reason is the inability to quickly heat the sensor used for controlling the air-to-fuel ratio in the exhausts, also called the lambda value, which is required to be in a particular range for the catalytic converter to work properly. This problem may be solved utilizing another, more robust sensor for this purpose.
This thesis presents the efforts made to test the SiC-based field effect transistor (SiC-FET) sensor technology both as an ammonia sensor for SCR systems and as a cold start lambda sensor. The SiC-FET sensor has been shown to be highly sensitive to ammonia both in laboratory and engine measurements. As a lambda sensor it has proven to be both sensitive and selective, and its properties have been studied in lambda stairs both in engine exhausts and in the laboratory. The influence of metal gate restructuring on the linearity of the sensor has also been investigated. The speed of response for both sensor types has been found to be fast enough for closed loop control in each application.
On the day of the public defence of the doctoral thesis, the status of article III was: in press. Report code: LiU-Tek-Lic-2003:50.
Mellin, Hannu Kaarlo Olavi. "The effect of high temperatures (30 degrees Celsius) on biological nutrient removal performance." Master's thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/21729.
Повний текст джерелаKrishnamoorthy, Vijay. "Effect of gas density on corrosion in horizontal multiphase slug flow at high temperatures and pressures." Ohio : Ohio University, 1997. http://www.ohiolink.edu/etd/view.cgi?ohiou1177096097.
Повний текст джерелаFry, J. C. "A study of the cooling effect of water sprays on steel strip at high temperatures." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637015.
Повний текст джерелаPeng, Yucheng. "EFFECT OF HIGH TEMPERATURES ON ADHESIVE BOND DURABILITY AND TOXIC CHEMICAL PRODUCTION FOR ENGINEERED WOOD PRODUCTS." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07082008-153319/.
Повний текст джерелаLindsay, John Christopher. "Stress corrosion cracking and internal oxidation of alloy 600 in high temperature hydrogenated steam and water." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/stress-corrosion-cracking-and-internal-oxidation-of-alloy-600-in-high-temperature-hydrogenated-steam-and-water(1d6b037c-baf1-4397-a6c9-43835e7bb39a).html.
Повний текст джерелаKarkhanis, Shalmira. "Macroscopic and microscopic changes in incinerated deciduous teeth." University of Western Australia. Centre for Forensic Science, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0170.
Повний текст джерелаLaurent, Véronique. "Mouillabilité et réactivité dans les systèmes composites métal/céramique : étude du couple Al/SiC." Grenoble INPG, 1988. http://www.theses.fr/1988INPG0115.
Повний текст джерелаPearson, Stephen R. "The effect of nitriding on the fretting wear of a high strength steel at ambient and elevated temperatures." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/29004/.
Повний текст джерелаTripp, David William. "The thermal regime during electron beam hearth remelting." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26748.
Повний текст джерелаApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Abdallah, Zakaria. "Creep lifing methods for components under high temperature creep." Thesis, Swansea University, 2010. https://cronfa.swan.ac.uk/Record/cronfa43065.
Повний текст джерелаAcquaye, Lucy. "Effect of high curing temperatures on the strength, durability and potential of delayed ettringite formation in mass concrete structures." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013837.
Повний текст джерелаTsantrizos, Panayotis G. "The characteristics of titanium tetrachloride plasmas in a transferred-arc systems /." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75670.
Повний текст джерелаFurthermore, an investigation was conducted into the feasibility of collecting titanium metal from the dissociated TiCl$ sb4$ molecule in the plasmagas. The titanium metal was collected in a molten bath, which also served as the anode in the transferred arc system. Three anode bath compositions were used in this study. Two of them, namely titanium and zirconium, were not able to reduce recombined titanium subchlorides in the bath. The third aluminum, was a reducing bath. When aluminum was used, about 60 percent of all titanium fed into the reactor was collected.
Finally, phenomena occurring on the surface of a thoriated tungsten cathode were studied in a transferred-arc reactor using argon or helium as the plasmagas. The effect of cathode geometry on the rate and mechanisms of cathode erosion were investigated. It was shown that the surface temperature of flat-tip cathodes operating in argon is near the melting point of tungsten. On the other hand, the surface temperature of flat-tip cathodes operating in helium and pointed-tip cathodes operating in either helium or argon are near the boiling point of tungsten. Some of the material vapourized from the cathode was redeposited on the cathode surface, forming crystals whose morphology and composition depended on their distance from the arc root and the plasmagas composition.
Havn, Torgeir Børresen. "The Effect of Catch and Release Angling at High Water Temperatures on Behavior and Survival of Atlantic Salmon (Salmo salar L.)." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23960.
Повний текст джерелаMcDonald, Teaghan. "Investigating the effect of high temperatures and substrates on the detection of human blood using the ABAcard® Hematrace® kit." Thesis, McDonald, Teaghan (2017) Investigating the effect of high temperatures and substrates on the detection of human blood using the ABAcard® Hematrace® kit. Masters by Coursework thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/37532/.
Повний текст джерелаKandasamy, Sasikaran, and s3003480@student rmit edu au. "Investigation of SiC Based Field Effect Sensors with Gas Sensitive Metal Oxide Layers for Hydrogen and Hydrocarbon Gas Sensing at High Temperatures." RMIT University. Electrical and Computer Engineering, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080724.142015.
Повний текст джерелаDuan, Runrun. "Investigation of xBi(B')O₃-(1 -- x)PbTiO₃ and xBi(B',B")O3-(1 -- x)PbTiO3 perovskite solid solutions with high transition temperatures." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/24688.
Повний текст джерелаFalahi, Khalil El. "Contribution à la conception de driver en technologie CMOS SOI pour la commande de transistors JFET SiC pour un environnement de haute température." Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0056/document.
Повний текст джерелаIn aeronautics, electrical systems progressively replace mechanical and hydraulic control systems. If the electronics can stand the absence of cooling, the immediate advantages will be the reduction of mass, increased performances, admissible reliability and thus reduction of costs. In aircraft, some important steps have already been performed successfully when substituting standard systems by electrical control system such as electrical brakes, thrust reverser, electrical actuators for flight control… Large band gap semiconductors (SiC, GaN…) have eased the operation in high temperature over the last decade and let overcome a weakness of conventional silicon systems (Si). High temperature power components such as Schottky diodes or JFET transistors, are already commercially available for a use up to 220°C, limited by package. Moreover inverters based on SiC JFET transistors have been realized and characterized at high temperature. Finally the control part of these power systems needs to be designed for harsh environment. It is in this context of lack of integrated control part that the FNRAE COTECH project and my doctoral research have been built. Based on a state of the art about drivers, the complex link between electronic and temperature and the potentialities of CMOS Silicon-On-Insulator technology (SOI) for high temperature applications have been underlined. The characterization of commercial SOI drivers gives essential data on these systems and their behavior at high temperature. These measurements also highlight the practical limitations of SOI technologies. The main part of this manuscript concerns the design and characterization of functions or IPs for high temperature JFET SiC driver. Two SOI runs in TFSmart1 have been realized. The developed functions include the driver output stage, associated buffers and protection functions. The drivers have been tested from -50°C up to 250°C without failure under short time-range. Moreover, an original protection function has been demonstrated against the short-circuit of an inverter leg. This function allows overcoming the main limitation of the normally on JFET transistor. Finally, an inverter module has been built for in-situ test of these new drivers
Shortlidge, Erin Elizabeth. "Testing the Ecological and Physiological Factors Influencing Reproductive Success in Mosses." PDXScholar, 2014. http://pdxscholar.library.pdx.edu/open_access_etds/1951.
Повний текст джерелаSabbah, Wissam. "Contribution à l’étude des assemblages et connexions nécessaires à la réalisation d’un module de puissance haute température à base de jfet en carbure de silicium (SiC)." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR12013/document.
Повний текст джерелаThe development of power components based on silicon carbide (SiC) allows for the design of power converter operating at high temperature (above 200 or 300°C). SiC is a semiconductor material with a large band gap that not only can operate in temperatures exceeding 300°C but also offers fast switching speed, high voltage blocking capability and higher thermal conductivity compared to silicon technology components. The classical die attach technology uses high temperature solder alloys which melt at around 300°C. However, even a soldered die attach with such high melting point can only operate up to a much lower temperature. Alternative die attach solutions have recently been proposed: Transient Liquid Phase Bonding, soldering with higher melting point alloys such as ZnSn, or silver sintering.Silver sintering is a very interesting technology, as silver offers very good thermal conductivity (429W/m.K, better than copper), relatively inexpensive (compared to alternative solutions which often use gold), and has a very high melting point (961°C).The implementation of two silver-sintering processes is made: one based on micrometer-scale silver particles, and one on nano-meter-scale particles. Two substrate technologies are investigated: Al2O3 DBC and Si3N4 AMB. After the process optimization, tests vehicles are assembled using nano and micro silver particles paste and a more classical high-temperature die attach technology: AuGe soldering. Multiple analyses are performed, such as thermal resistance measurement, shear tests and micro-sections to follow the evolution of the joint during thermal cycling and high-temperature storage ageing
Wilcox, Edward. "Silicon-germanium devices and circuits for cryogenic and high-radiation space environments." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33850.
Повний текст джерелаGupta, Niraj. "First Principles Study of Metastable Beta Titanium Alloys." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804949/.
Повний текст джерелаMogniotte, Jean-François. "Conception d'un circuit intégré en SiC appliqué aux convertisseur de moyenne puissance." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0004/document.
Повний текст джерелаThe new SiC power switches is able to consider power converters, which could operate in harsh environments as in High Voltage (> 10kV) and High Temperature (> 300 °C). Currently, they are no specific solutions for controlling these devices in harsh environments. The development of elementary functions in SiC is a preliminary step toward the realization of a first demonstrator for these fields of applications. AMPERE laboratory (France) and the National Center of Microelectronic of Barcelona (Spain) have elaborated an elementary electrical compound, which is a lateral dual gate MESFET in Silicon Carbide (SiC). The purpose of this research is to conceive a monolithic power converter and its driver in SiC. The scientific approach has consisted of defining in a first time a SPICE model of the elementary MESFET from electric characterizations (fitting). Analog functions as : comparator, ring oscillator, Schmitt’s trigger . . . have been designed thanks to this SPICE’s model. A device based on a bridge rectifier, a regulated "boost" and its driver has been established and simulated with the SPICE Simulator. The converter has been sized for supplying 2.2 W for an area of 0.27 cm2. This device has been fabricated at CNM of Barcelona on semi-insulating SiC substrate. The electrical characterizations of the lateral compounds (resistors, diodes, MESFETs) checked the design, the "sizing" and the manufacturing process of these elementary devices and analog functions. The experimental results is able to considerer a monolithic driver in Wide Band Gap. The prospects of this research is now to realize a fully integrated power converter in SiC and study its behavior in harsh environments (especially in high temperature > 300 °C). Analysis of degradation mechanisms and reliability of the power converters would be so considerer in the future
Hamieh, Youness. "Caractérisation et modélisation du transistor JFET en SiC à haute température." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00665817.
Повний текст джерелаSmith, Benjamin Daniel. "Microstructure-sensitive plasticity and fatigue of three titanium alloy microstructures." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49237.
Повний текст джерелаNarang, Vikas A. "Heat Transfer Analysis In Steel Structures." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050405-133533/.
Повний текст джерелаSylvestre, Alain. "Evolution des proprietes electriques et physiques aux basses temperatures de transistors a effet de champ a heterojonction a grille courte sur substrat inp." Paris 11, 1996. http://www.theses.fr/1996PA112020.
Повний текст джерелаLokvenc, Martin. "Testování lomové houževnatosti za vysokých teplot s využitím miniaturních CT těles." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231784.
Повний текст джерелаArakelian, Andrea Katherine. "Strength analysis of bolted shear connections under fire conditions using the finite element approach." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-122208-145717/.
Повний текст джерелаLin, Shih-Min, and 林士民. "Microstructures of Silicon Carbides Sintered at High- temperatures and Their Significance of Sintering." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/42135353544183578327.
Повний текст джерела國立成功大學
地球科學系
83
Silicon carbides sintered at high temperatures including refractory bricks, refractory plates, kiln furniture and heating elements have been collected and analyzed for their microstructures in the present study. On the basis of microstructures, the following four different types of sintered silicon carbides have been recognized: clay-bonded, sialon- bonded, self-bonded and recrystallized silicon carbides. In the clay-bonded silicon carbides, the silicon carbide grains are surrounded by fine-grained cristobalites, mullites of needle form, small amounts of Al2O3- and SiO2-rich amorphous phases, Fe-Si alloy of chondritic form and whiskers of β-silicon carbide. In the sialon-bonded silicon carbides, the silicon carbide grains were surrounded by frame-worked β'-sialon crystals and corundums. In the sintering process, Si3N4 and Al2 O3 were used as sintering agents and were sintered in nitrogen atmosphere. In the self-bonded silicon carbides, the silicon carbide grains were necked among one another and the surface of the grains were coated with thin films of cristbalites. In the recrystallized silicon carbides, in addition to the necking, the silicon carbide crystals have grown well and penetrated each other.
Hu, Guixing. "Oxygen isotope salt effect at high pressure and high temperature /." 2000. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:9990561.
Повний текст джерела許邦聖. "Effect of different storage temperatures on the quality of high oleic peanut(Arachis hypogaea L.)." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/fm6455.
Повний текст джерелаCadell, Seth R. "Development of a binary mixture gas composition instrument for use in a confined high temperature environment." Thesis, 2012. http://hdl.handle.net/1957/36206.
Повний текст джерелаGraduation date: 2013
Peng, Min-Ru, and 彭敏茹. "Electrical Characteristics and Hot-Carrier Effect of Stacked High-k/Metal-Gate nMOSFETs under Nitridation Annealing Temperatures." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/qvz6gd.
Повний текст джерела國立臺北科技大學
機電整合研究所
101
Since 45nm process generation and beyond, high-k/metal-gate (HK/MG) combining strain engineering technology for nano-scale MOSFETs incorporated into the conventional CMOS process is available and promising to increase the drive current. In the past, after gate dielectric deposition, the annealing process with nitrogen gas was commonly adopted to repair the existence of defects in gate dielectric and therefore improve the quality of interfacial layer in MOSFETs. However, few published researches discussed the nitridation effect of decoupled plasma nitridation (DPN) process with the hot-carrier effect and electrical characteristics at different annealing temperatures. In this study, I focus on these points and try to establish these relationships. In this work, the tested 28nm wafers came from UMC. The hafnium-based gate dielectric with a profile of HfOx/ZrOy/HfOz (HZH) was deposited with atomic layer deposition (ALD) technology. The experimental parameters include the different channel lengths and stress temperatures. Consequently, through the statistical and analytical analysis of experimental data, the nitridation effect with annealing temperatures reflecting the various results of device electrical characteristics are exposed in this thesis. After the analysis, the annealing temperatures after DPN treatments do not obviously impact the device performance. Owing to the stronger horizontal electrical field, the degradation of short channel nMOSFETs with L=0.03?m in channel hot-carrier (CHC) stress is more serious than that with L=1?m. Additionally, for the identical L, the worst degradation of nMOSFETs with CHC test is the samples of 8% N2 concentration and 900℃ annealing temperature stressed at 125℃. This may attribute to the formation of thicker oxide interfacial layer (IL) and was annealed cause crystallization.
吳宛蓉. "Characterization and Analysis of Impact Ionization Effect of Sb-based High Electron Mobility Transistors at Low Temperatures." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/63049703207314832450.
Повний текст джерела國立彰化師範大學
電子工程學系
102
Sb-based high electron mobility transistors (HEMTs) with InAs as the channel layer have excellent electron mobility, making them very suitable for ultra-high-speed, low-power electronic devices. However, the narrow energy band gap of InAs is inherently accompanied with strong impact ionization. In this thesis, we measure the low-temperature characteristics of Sb-based HEMTs and analyze the effect of impact ionization on the device characteristics at various temperatures. To explore the impact ionization effect in depth, we establish a simplified modal theory to fit the experimental current-voltage curves so that the ideal current and the impact ionization current can be extracted. Our study clearly shows that the impact ionization effect in the HEMTs with the channel layer of small band gap can be significant even under low electric field. Besides, the current contributed by impact ionization becomes larger at lower temperatures.
Morudu, Kholo Veronica. "Influence of temperature on the metal dusting of alloy 800." Thesis, 2018. https://hdl.handle.net/10539/27004.
Повний текст джерелаMetal dusting (MD) is a severe form of corrosion in which iron, steels, and nickel (Ni) and cobalt (Co) based alloys disintegrate into a metal or carbide powder with a coke deposit when exposed to strongly carburising gases (carbon activity, ac>1) at elevated temperatures (400800°C). Temperature affects both the driving force and rate of the reaction, represented by gas phase supersaturation with carbon, and the rates of the various processes involved in converting that energy difference into the dusting process. Therefore, process streams such as reformer gas can be benign when hot, but becomes aggressive below critical temperatures. There are different views in literature about the effect of temperature on metal dusting of different materials and alloys. Alloy 800 experiences metal dusting (MD) at 525°C, which is the temperature of the tube sheet of reformers in petrochemical industry. This alloy is specifically used for tube ferrules in the reformers. The reformer trains can reach a critical (highest) internal temperature of 650°C. Therefore, these two temperatures were compared. The effect of temperature and exposure time on the metal dusting of Alloy 800 were investigated in terms of the form of attack and the degradation mechanism. From the results obtained, it was observed that the longer exposure periods result in more carbon deposition and the carbon filaments in the coke become finer as compared to the nanotubes obtained after shorter exposure periods. The alloy suffered metal dusting attack after a relatively short exposure period of three days (72 hours) at both temperatures of 525°C and 650°C, with very little coking.
TL2019
Tao, Ju Zhou. "Theory of negative thermal expansion." Thesis, 2002. http://hdl.handle.net/1957/31094.
Повний текст джерелаGraduation date: 2003
Krejci, Michael. "Development of a New Flame Speed Vessel to Measure the Effect of Steam Dilution on Laminar Flame Speeds of Syngas Fuel Blends at Elevated Pressures and Temperatures." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-10978.
Повний текст джерелаMantyi, Hadio Caprice. "High temperature oxidation and corrosion behaviour of titanium aluminide alloy Ti-52.5AI-10.0Ni-0.2Ru (at.%)." Thesis, 2016. http://hdl.handle.net/10539/22671.
Повний текст джерелаThe alloys Ti-52.5Al-10.0Ni (at.%) and Ti-52.5Al-10.0Ni-0.2Ru (at.%) were made by mixing, and melting their powders in a button arc furnace under an argon atmosphere. The high temperature oxidation and room temperature corrosion of behaviour of the alloys was investigated. Isothermal oxidation in air at 950°C for 120 hours and 720 hours was done. Cyclic oxidation behaviour of the alloys was also investigated in air and in a hot salt (Na2SO4) environment. The corrosion tests were conducted in 5 wt% and 25 wt% HCl. All the samples were characterised using scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction and hardness measurements. On solidification, the Ti-52.5Al-10.0Ni (at.%) alloy formed dendrites of γ-TiAl (~55 at.% Al) surrounded by a eutectic of γ-TiAl + Ti2NiAl3 (τ3) phases. Most of the nickel was found in the Ti2NiAl3 (τ3) phase (~12 at.%) with trace amounts in the dendrites (~0.5 at.%). The Ti-52.5Al-10.0Ni-0.2Ru (at.%) alloy formed dendrites of γ-TiAl (~53 at.% Al) surrounded by a eutectic of γ-TiAl + Ti2NiAl3 (τ3). Most of the nickel (~15 at.%) and ruthenium (~0.3 at.%) were in solid solution in the Ti2NiAl3 (τ3) phase, although small amounts of both metals were present in the dendrites (~1 at.% Ni and 0.1 at.% Ru). Under isothermal oxidation conditions, both alloys showed good oxidation resistance with a low mass gain (< 2%). The alloys formed a continuous scale of TiO2 and Al2O3 with good adherence to the substrate, but as exposure time increased, the scale was severely degraded and exfoliated from the surface. Cyclic oxidation conditions were more aggressive for both alloys. The Ti-52.5Al-10.0Ni-0.2Ru (at.%) alloy was more resistant and formed a nickel-rich sub-surface zone between the substrate and intermixed oxide layer. Both alloys had a fairly good corrosion resistance in HCl due to the presence of nickel. They formed a thin and non-continuous Al2O3 oxide scale on the surface of the γ-TiAl dendrites, with Ti3NiAl2O on the γ-TiAl + Ti2NiAl3 (τ3) eutectic regions. The acid mainly corroded the τ3 phase, thus attacking the eutectic and leaving the γ-TiAl dendrites exposed.
MT2017
Keller, Nicole Simone. "Metals and volatiles in melts : an experimental and field study." Phd thesis, 2008. http://hdl.handle.net/1885/150923.
Повний текст джерелаMalwela, Thomas. "The study of bionanocomposite thin films and their crystal growth behaviour." Thesis, 2014. http://hdl.handle.net/10210/12337.
Повний текст джерелаThis study focuses on the morphology and crystal-growth behaviour of polyactide (PLA)-based blends and blends modified with organoclay thin films. The study further examined the effect of blending and the incorporation of organoclays on the enzymatic degradation behaviour. Thin films of unmodified and nanoclay-modified PLA/poly(butylene succinate) (PBS) blends were cast on a glass substrate by a spin coater, while thin films of biodegradable PLA/poly[(butylene succinate)-coadipate] PBSA blends and blends containing organoclays were cast on a silicon (100) wafer substrate. The morphology and crystal growth behaviour of the thin films crystallized at different temperatures were examined with an atomic force microscopy (AFM) equipped with a hot-stage scanner. In PLA/PBS blend thin films, AFM images showed that the size of the dispersed PBS phase was influenced by C30B clay loading on the blends. The dispersed size reduced on the addition of C30B clay up to 2 wt%, beyond which, dispersed size began to increase. Transmission electron microscopy studies indicated that this behaviour was due to the preferential location of silicates in the PBS phase than in the PLA phase. For thin films annealed at 60 °C, the additi on of organoclays to the blend quenched the growth of edge-on lamellae. The crystalline morphologies at 120 °C were dominated by edge-on lamellae grown, around the PBS phase to form spherulites. Morphologies of thin films crystallized at 120 °C from melt were dominated by the flat-on lamellae, while those crystallized at 70 °C from melt were dominated by the edge-on lamellae. In the case of PLA/PBSA blend thin films, the results indicated that the size and distribution of the dispersed phase were directly related to the blend composition. The crystal growth behaviours indicated the presence of homogeneous and heterogeneous nucleations, and the nature of nucleation was directly related to the blend ratio and the temperature at which crystallization occurred. Therefore, this study will facilitate the understanding of crystal growth behaviour in a confined environment and will enable the modulation of the blend properties.
Ramalall, Dawlall Shahil. "The relationship between the metal dusting mechanism and the synthesis of carbon nanofilaments using toluene and a nickel based alloy." Thesis, 2016. http://hdl.handle.net/10539/21729.
Повний текст джерелаMetal dusting (MD) is a severe type of corrosion that occurs mainly in petrochemical industries. The occurrence of MD is mainly due to syngas attacking Fe-, Ni- and Co-based alloys at elevated temperatures. More recently, literature has shown that apart from syngas, liquid hydrocarbon sources have been causing problems on platformer units in refineries. In the first part of this study a highly corrosion resistant Ni-based alloy (Hastelloy C276), in its polished form, was subjected to MD conditions at 800 °C using a liquid hydrocarbon (toluene) and helium (carrier gas) for 1 h. Exposure to these conditions revealed the formation of carbon nanofilaments and graphite layers which were confirmed by laser Raman spectroscopy, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Burning off the carbon nanofilaments and the graphite layers in laboratory air for 1 h at 800 °C revealed that pits were formed on the Hastelloy C276. These same pits were not evident when Hastelloy C276 was exposed to either the carrier gas (helium) or laboratory air alone. Besides MD being a continuous problem in industry, this mechanism has been shown to be beneficial in the synthesis of carbon nanofilaments viz., carbon nanofibers (CNTs) and nanotubes (CNFs). In the second part of this study, unpolished Hastelloy C276 blocks (as opposed to polished blocks) were used to synthesize carbon nanofilaments. This was done as prior studies had shown that carbon nanofilaments were produced with better quality and greater yields this way. Here the flow rate (80, 160 and 240 mL/min) and reaction duration (10, 15, 30, 45, 60, 120 and 240 min) were studied using toluene (a liquid hydrocarbon). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to assess the quality and quantity of the carbon nanofilaments synthesized. Besides the formation of carbon nanofilaments, a less important material known as graphite particle structures (GPSs) were also synthesized. These studies collectively showed that MD had taken place on the surface of Hastelloy C276 when exposed to toluene at 800 °C.
TG2016
Kim, Hyeong Jun. "Thermal effects on modular maglev steel guideways." Thesis, 2007. http://hdl.handle.net/2152/3282.
Повний текст джерелаtext
Liang, YUAN-MING, and 梁原銘. "Application of Failure Mode and Effect Analysis in Risk Assessment and Management of Equipment Used in High-operating Temperatures for Production Processes – A Case Study of a Semiconductor Factory." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/59w9qh.
Повний текст джерела國立中央大學
環境工程研究所在職專班
106
In the semiconductor packaging and testing industry, many raw materials (such as flammable chemicals, strong acids, strong alkalis, strong oxidizing substances and flammable gases) are used in various processes equipment operated at high temperatures according to the process requirements. While the products are regulated by the relevant laws and regulations, these laws and regulations are not as clear and specific as the standards that can be followed in foreign countries, resulting in that enterprises can only rely on the experience to set up their equipment procurement specifications. In this case, it is easy to derive the fire caused by poor equipment safety design and improper on-site management. In addition, the design of the plant is mostly in a closed environment, which leads to the difficulty of people evacuation and disaster relief when the fire occurs. In this study, the Failure Mode and Effect Analysis (FMEA) and EMI S10 risk assessment method are used to analyze the hazards that can be caused in the process of equipment with high-temperature operation (i.e., High Temperature Equipment) by the functional failure of apparatus components, exhaust system and the safety interlock devices, and study the improvement countermeasures according to the risk assessment results. Using a semiconductor packaging and testing industry as a case, the failure analysis of the fire project caused by the process of High Temperature Equipment reveals that (i) among the Equipment Components, the highest risk priority number is when the element material is carbonated (RPN was 320); (ii) in the Exhaust System, when the pipeline full of internal condensation, the highest risk priority number is scored 392; (iii) among the Safety interlock System, the highest risk priority number of the safety interlock devices and the temperature detection devices are scored 336. According to the analysis of various failure items, it was found that the reason of the high risk priority, apart from causality, the general problems are lack of existing prevention and detection deficiencies, which leads to the failure to prevent the occurrence. This study also takes how to early prevention of failures as an improvement strategy to compare the differences between before and after improvement that is made. It is found that the abnormity of the equipment components is carbonated by the element material, the RPN scored is reduced to 128; the RPN scored of the safety interlock system is reduced to 96, and the RPN scored of the temperature detection system is reduced to 144; in exhaust pipe, the abnormal internal condensation in the pipeline which RPN scored fell from 392 to 112. From the outcome of the improvement, it is known that the Standards should be set up early in the stage of equipment planning and evaluation to reduce the failure rate of process equipment during operation. According to the above results, the risk value of internal condensation of exhaust pipeline is the highest, resulting in condensation phenomenon caused when a high temperature gas contacting with cold surfaces. The second high risk value is the safety interlock system, because the equipment machine is not connected with the safety interlock devices. The element material carbonation ranks the third place, because the component temperature exceeds the circuit insulation temperature. Hence. the above projects in the management control should be strengthened via personnel routine testing, cleaning frequency and regular infrared thermal imaging instrument to measure temperature; further, in engineering control, a condensation collecting plate and the exhaust flow detector can be set up inside the exhaust pipe and safety interlock system should controlled by double and double loop protection devices; lastly, the material carbonation of the circuit material should be replaced with a heat-resistant material.
Thirunavukarasu, Balamurugesh. "A study of solidification dynamics with liquid mass influx." Thesis, 2003. http://hdl.handle.net/1957/31591.
Повний текст джерелаGraduation date: 2003
"Simulation study on the effects of heat and ash on a frequently burnt soil in Hong Kong." 2005. http://library.cuhk.edu.hk/record=b5892332.
Повний текст джерелаThesis submitted in: November 2004.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 124-140).
Abstracts in English and Chinese.
Abstract --- p.i
Acknowledgement --- p.vii
Table of contents --- p.viii
List of Tables --- p.xi
List of Figures --- p.xiii
List of Plates --- p.xiv
Chapter CHAPTER ONE --- Introduction
Chapter 1.1 --- Introduction --- p.1
Chapter 1.2 --- Background and ecological impact of hill fires in Hong Kong --- p.2
Chapter 1.3 --- Conceptual framework of study --- p.4
Chapter 1.4 --- Objectives of the study --- p.10
Chapter 1.5 --- Significance --- p.11
Chapter 1.6 --- Organization of the thesis --- p.12
Chapter CHAPTER TWO --- The study area
Chapter 2.1 --- Introduction --- p.14
Chapter 2.2 --- Geographical setting of Hong Kong --- p.14
Chapter 2.2.1 --- Climate of Hong Kong --- p.14
Chapter 2.2.2 --- Geology of Hong Kong --- p.15
Chapter 2.2.3 --- Soils of Hong Kong --- p.16
Chapter 2.2.4 --- Vegetation of Hong Kong --- p.17
Chapter 2.3 --- Site selection --- p.18
Chapter 2.4 --- Grassy Hill --- p.20
Chapter CHAPTER THREE --- Heating effect on the properties of ash
Chapter 3.1 --- Introduction --- p.23
Chapter 3.2 --- Experimental design and methodology
Chapter 3.2.1 --- Selection of simulation heating --- p.26
Chapter 3.2.2 --- "Heating intensity at 200°-600°C for 1,5 and 15 minutes" --- p.27
Chapter 3.2.3 --- Field work --- p.27
Chapter 3.2.4 --- Heating method --- p.28
Chapter 3.2.5 --- Chemical analysis --- p.28
Chapter 3.2.6 --- Analysis of data --- p.32
Chapter 3.3 --- Results and Discussion
Chapter 3.3.1 --- Heating effect on ash weight and pH --- p.33
Chapter 3.3.2 --- "Heating effect on ash organic C, N and P" --- p.33
Chapter 3.3.3 --- Heating effect on ash available cations --- p.40
Chapter 3.4 --- Conclusion --- p.42
Chapter CHAPTER FOUR --- The effect of heat and ash on soil
Chapter 4.1 --- Introduction --- p.44
Chapter 4.2 --- Methodology
Chapter 4.2.1 --- Field work --- p.48
Chapter 4.2.2 --- Soil heating methods --- p.48
Chapter 4.2.3 --- Chemical analysis --- p.49
Chapter 4.2.4 --- Statistical analysis --- p.52
Chapter 4.3 --- Results and Discussion
Chapter 4.3.1 --- The effect of heat and ash on soil pH --- p.53
Chapter 4.3.2 --- "The effect of heat and ash on soil organic matter, N and P" --- p.55
Chapter 4.3.3 --- The effect of heat and ash on soil cations --- p.62
Chapter 4.4 --- Conclusion --- p.65
Chapter CHAPTER FIVE --- Nitrogen and phosphorus mineralization after heating
Chapter 5.1 --- Introduction --- p.67
Chapter 5.2 --- Methodology
Chapter 5.2.1 --- Heating and incubation method --- p.70
Chapter 5.2.2 --- Laboratory methods --- p.72
Chapter 5.2.3 --- Statistical analysis --- p.72
Chapter 5.3 --- Results and discussion
Chapter 5.3.1 --- Temporal changes of N mineralization in heated bare soils --- p.72
Chapter 5.3.2 --- The effect of ash on N mineralization --- p.78
Chapter 5.3.3 --- Comparison of N mineralization with other studies --- p.79
Chapter 5.3.4 --- Temporal changes of P mineralization in the heated bare soils --- p.81
Chapter 5.3.5 --- The effect of ash on P mineralization --- p.83
Chapter 5.3.6 --- Comparison of P mineralization to other studies --- p.84
Chapter 5.4 --- Conclusion --- p.85
Chapter CHAPTER SIX --- Vertical movement of mineral N in ash-covered soil columns
Chapter 6.1 --- Introduction --- p.87
Chapter 6.2 --- Methodology
Chapter 6.2.1 --- Package of soil columns --- p.89
Chapter 6.2.2 --- Water addition and extraction of pore water --- p.90
Chapter 6.2.3 --- Statistical analysis --- p.92
Chapter 6.3 --- Results and Discussion
Chapter 6.3.1 --- Mineral N in the pore water --- p.92
Chapter 6.3.2 --- The effect of ash on mineral N in pore water --- p.97
Chapter 6.3.3 --- The leaching loss of mineral N --- p.98
Chapter 6.3.4 --- Comparisons with other studies --- p.103
Chapter 6.4 --- Conclusion --- p.105
Chapter CHAPTER SEVEN --- Integrative discussion
Chapter 7.1 --- Summary of major findings --- p.107
Chapter 7.2 --- Clarifying some misconceptions about the effect of fire --- p.110
Chapter 7.3 --- Estimated losses of N and P from heating --- p.112
Chapter 7.4 --- Nutrient supplying capacity of soils after heating --- p.115
Chapter 7.5 --- Why are repeatedly burnt areas reduced to grassland? --- p.118
Chapter 7.6 --- Implication on the restoration of fire-affected areas --- p.119
Chapter 7.7 --- Limitations of the study --- p.121
Chapter 7.8 --- Suggestions for future research --- p.122
References --- p.124
Appendices --- p.141
Kunc, Jan. "Dvourozměrný elektronový plyn v kvantových jamách CdTE: studie ve vysokých magnetických polích." Doctoral thesis, 2011. http://www.nusl.cz/ntk/nusl-296138.
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